Hepatocellular carcinoma(HCC)is one of the most common human cancers,and its incidence is still increasing in many countries.The prognosis of HCC patients remains poor,and identification of useful molecular prognostic...Hepatocellular carcinoma(HCC)is one of the most common human cancers,and its incidence is still increasing in many countries.The prognosis of HCC patients remains poor,and identification of useful molecular prognostic markers is required.Many recent studies have shown that functional alterations of cell-cycle regulators can be observed in HCC.Among the various types of cell-cycle regulators,p16 and p27 are frequently inactivated in HCC and are considered to be potent tumor suppressors.p16,a G1-specific cell-cycle inhibitor that prevents the association of cyclindependent kinase(CDK)4 and CDK6 with cyclin D1,is frequently inactivated in HCC via CpG methylation of its promoter region.p16 may be involved in the early steps of hepatocarcinogenesis,since p16 gene methylation has been detected in subsets of pre-neoplastic liver cirrhosis patients.p27,a negative regulator of the G1-S phase transition through inhibition of the kinase activities of Cdk2/cyclin A and Cdk2/cyclin E complexes,is now considered to be an adverse prognostic factor in HCC.In some cases of HCC with increased cell proliferation,p27 is overexpressed but inactivated by sequestration into cyclin D1-CDK4-containing complexes.Since loss of p16 is closely related to functional inactivation of p27 in HCC, investigating both p16 and p27 may be useful for precise prognostic predictions in individuals with HCC.展开更多
Aim: To determine the mechanisms of glucocorticoids in inhibiting advanced prostate cancer growth. Methods: The cell proliferation and cell cycle of prostate cancer DU145 cells following dexamethasone treatment were...Aim: To determine the mechanisms of glucocorticoids in inhibiting advanced prostate cancer growth. Methods: The cell proliferation and cell cycle of prostate cancer DU145 cells following dexamethasone treatment were determined by proliferation assay and fluorescence-activated cell sorter. Western blot analysis was carried out to evaluate the effects of dexamethasone on phosphorylation of extracellular signal-regulated kinase (ERK)1/2 and expression of cyclin D1 in DU145 cells with or without glucocorticoid receptor (GR) antagonist RU486. Reverse transcription- polymerase chain reaction verified the expression of GR mRNA in DU145 cells. Results: Dexamethasone significantly inhibited DU 145 cell proliferation at the G0/G1 phase. Westem blot analysis showed a dramatic reduction of ERK1/2 activity and cyclin D1 expression in dexamethasone-treated cells. The decreased phosphorylation of ERK1/2 in dexamethasone-treated cells was attenuated by GR blockade. Additionally, the effects of dexamethasone in inhibiting cyclin D1 expression were altered by GR blockade. Conclusion: Dexamethasone suppresses DU145 cell proliferation and cell cycle, and the underlying mechanisms are through the inhibition of phosphorylation of ERK1/2 and cyclin D1 expression. The inhibition of ERK1/2 phosphorylation and cyclin D1 expression is attenuated by GR blockade, suggesting that GR regulates ERK1/2 and cyclin D1 pathways. These observations suggest that dexamethasone has a potential clinical application in prostate cancer therapy.展开更多
AIM: To investigate the growth inhibitory mechanism of NS-398, a selective cyclooxygenase-2 (COX-2) inhibitor, in two hepatocellular carcinoma (HCC) cell lines (HepG2 and Huh7). METHODS: HepG2 and Huh7 cells were trea...AIM: To investigate the growth inhibitory mechanism of NS-398, a selective cyclooxygenase-2 (COX-2) inhibitor, in two hepatocellular carcinoma (HCC) cell lines (HepG2 and Huh7). METHODS: HepG2 and Huh7 cells were treated with NS-398. Its effects on cell viability, cell proliferation, cell cycles, and gene expression were respectively evaluated by water-soluble tetrazolium salt (WST-1) assay, 4’-6-diamidino-2-phenylindole (DAPI) staining, flow cytometer analysis, and Western blotting, with dimethyl sulfoxide (DMSO) as positive control. RESULTS: NS-398 showed dose- and time-dependent growth-inhibitory effects on the two cell lines. Proliferating cell nuclear antigen (PCNA) expressions in HepG2 and Huh7 cells, particularly in Huh7 cells were inhibited in a time- and dose-independent manner. NS-398 caused cell cycle arrest in the G1 phase with cell accumulation in the sub-G1 phase in HepG2 and Huh7 cell lines. No evidence of apoptosis was observed in two cell lines. CONCLUSION: NS-398 reduces cell proliferation by inducing cell cycle arrest in HepG2 and Huh7 cell lines, and COX-2 inhibitors may have potent chemoprevention effects on human hepatocellular carcinoma.展开更多
Background:The cell cycle is at the center of cellular activities and is orchestrated by complex regulatory mechanisms,among which transcriptional regulation is one of the most important components.Alternative splicin...Background:The cell cycle is at the center of cellular activities and is orchestrated by complex regulatory mechanisms,among which transcriptional regulation is one of the most important components.Alternative splicing dramatically expands the regulatory network by producing transcript isoforms of genes to exquisitely control the cell cycle.However,the patterns of transcript isoform expression in the cell cycle are unclear.Therapies targeting cell cycle checkpoints are commonly used as anticancer therapies,but none of them have been designed or evaluated at the alternative splicing transcript level.The utility of these transcripts as markers of cell cycle-related drug sensitivity is still unknown,and studies on the expression patterns of cell cycle-targeting drug-related transcripts are also rare.Methods:To explore alternative splicing patterns during cell cycle progression,we performed sequential transcriptomic assays following cell cycle synchronization in colon cancer HCT116 and breast cancer MDA-MB-231 cell lines,using flow cytometry and reference cell cycle transcripts to confirm the cell cycle phases of samples,and we developed a new algorithm to describe the periodic patterns of transcripts fluctuating during the cell cycle.Genomics of Drug Sensitivity in Cancer(GDSC)drug sensitivity datasets and Cancer Cell Line Encyclopedia(CCLE)transcript datasets were used to assess the correlation of genes and their transcript isoforms with drug sensitivity.We identified transcripts associated with typical drugs targeting cell cycle by determining correlation coefficients.Cytotoxicity assays were used to confirm the effect of ENST00000257904 against cyclin dependent kinase 4/6(CDK4/6)inhibitors.Finally,alternative splicing transcripts associated with mitotic(M)phase arrest were analyzed using an RNA synthesis inhibition assay and transcriptome analysis.Results:We established high-resolution transcriptome datasets of synchronized cell cycle samples from colon cancer HCT116 and breast cancer MDA-MB-231 cells.The results of the cell cycle assessment showed that 43,326,41,578 and 29,244 transcripts were found to be periodically expressed in HeLa,HCT116 and MDA-MB-231 cells,respectively,among which 1280 transcripts showed this expression pattern in all three cancer cell lines.Drug sensitivity assessments showed that a large number of these transcripts displayed a higher correlation with drug sensitivity than their corresponding genes.Cell cycle-related drug screening showed that the level of the CDK4 transcript ENST00000547281 was more significantly associated with the resistance of cells to CDK4/6 inhibitors than the level of the CDK4 reference transcript ENST00000257904.The transcriptional inhibition assay following M phase arrest further confirmed the M-phase-specific expression of the splicing transcripts.Combined with the cell cycle-related drug screening,the results also showed that a set of periodic transcripts,for example,ENST00000314392(a dolichylphosphate mannosyltransferase polypeptide 2 isoform transcript),was more associated with drug sensitivity than the levels of their corresponding gene transcripts.Conclusions:In summary,we identified a panel of cell cycle-related periodic transcripts and found that the levels of transcripts of drug target genes showed different values for predicting drug sensitivity,providing novel insights into alternative splicing-related drug development and evaluation.展开更多
Aurora kinases play an important role in the cell cycle. These enzymes help establish mitotic spindles by directing centrosome duplication and separation and by regulating the spindle assembly checkpoint thereby helpi...Aurora kinases play an important role in the cell cycle. These enzymes help establish mitotic spindles by directing centrosome duplication and separation and by regulating the spindle assembly checkpoint thereby helping control cytokinesis. An over-expression of aurora kinases has been reported in a variety of human tumors. In this study, we identified the expression of aurora-A and aurora-B kinases in canine malignant lymphoid cells. We also evaluated the effects of the aurora kinase inhibitor (ZM447439), and found that this inhibitor decreases cell viability, increases DNA content change, and leads to apoptosis in canine B- and T-cell lymphoid cell lines. The lymphotoxicity induced by ZM447439 in these canine lymphoid cell lines suggests that further in vivo evaluation of aurora kinase inhibitors as a potential treatment for canine malignant lymphoid tumors is warranted.展开更多
BACKGROUND Growth arrest-specific gene 2(GAS2)plays a role in modulating in reversible growth arrest cell cycle,apoptosis,and cell survival.GAS2 protein is universally expressed in most normal tissues,particularly in ...BACKGROUND Growth arrest-specific gene 2(GAS2)plays a role in modulating in reversible growth arrest cell cycle,apoptosis,and cell survival.GAS2 protein is universally expressed in most normal tissues,particularly in the liver,but is depleted in some tumor tissues.However,the functional mechanisms of GAS2 in hepatocellular carcinoma(HCC)are not fully defined.AIM To investigate the function and mechanism of GAS2 in HCC.METHODS GAS2 expression in clinic liver and HCC specimens was analyzed by real-time PCR and western blotting.Cell proliferation was analyzed by counting,MTS,and colony formation assays.Cell cycle analysis was performed by flow cytometry.Cell apoptosis was investigated by Annexin V apoptosis assay and western blotting.RESULTS GAS2 protein expression was lower in HCC than in normal tissues.Overexpression of GAS2 inhibited the proliferation of HCC cells with wide-type p53,while knockdown of GAS2 promoted the proliferation of hepatocytes(P<0.05).Furthermore,GAS2 overexpression impeded the G1-to-S cell cycle transition and arrested more G1 cells,particularly the elevation of sub G1(P<0.01).Apoptosis induced by GAS2 was dependent on p53,which was increased by etoposide addition.The expression of p53 and apoptosis markers was further enhanced when GAS2 was upregulated,but became diminished upon downregulation of GAS2.In the clinic specimen,GAS2 was downregulated in more than 60%of HCCs.The average fold changes of GAS2 expression in tumor tissues were significantly lower than those in paired non-tumor tissues(P<0.05).CONCLUSION GAS2 plays a vital role in HCC cell proliferation and apoptosis,possibly by regulating the cell cycle and p53-dependent apoptosis pathway.展开更多
Background:Astrocytes become reactive following many types of CNS injuries.Excessive astrogliosis is detrimental and contributes to neuronal damage.We sought to determine whether inhibition of cell cycle could decreas...Background:Astrocytes become reactive following many types of CNS injuries.Excessive astrogliosis is detrimental and contributes to neuronal damage.We sought to determine whether inhibition of cell cycle could decrease the proliferation of astroglial cells and therefore reduce excessive gliosis and glial scar formation after focal ischemia.Methods:Cerebral infarction model was induced by photothrombosis method.Rats were examined using MRI,and lesion volumes were estimated on day 3 post-infarction.The expression of glial fibrillary acidic protein(GFAP) and proliferating cell nuclear antigen(PCNA) was observed by immunofluorescence staining.Protein levels for GFAP,PCNA,Cyclin A and Cyclin B1 were determined by Western blot analysis from the ischemic and sham animals sacrificed at 3,7,30 days after operation.Results:Cell cycle inhibitor olomoucine significantly suppressed GFAP and PCNA expression and reduced lesion volume after cerebral ischemia.In parallel studies,we found dense astroglial scar in boundary zone of vehicle-treated rats at 7 and 30 days.Olomoucine can markedly attenuate astroglial scar formation.Western blot analysis showed increased protein levels of GFAP,PCNA,Cyclin A and Cyclin B1 after ischemia,which was reduced by olomoucine treatment.Conclusion: Our results suggested that astroglial activation,proliferation and subsequently astroglial scar formation could be partially inhibited by regulation of cell cycle.Cell cycle modulation thereby provides a potential promising strategy to treat cerebral ischemia.展开更多
In this paper,we study the ability of DNA-PK-deficient(M059J) and -proficient(M059K) cells to undergo the rate of cellular proliferation,cell cycle distribution and apoptosis after 10 Gy X-ray irradiation,and the role...In this paper,we study the ability of DNA-PK-deficient(M059J) and -proficient(M059K) cells to undergo the rate of cellular proliferation,cell cycle distribution and apoptosis after 10 Gy X-ray irradiation,and the role of DNA-PK in radiosensitivity.The results showed that M059J cells exhibited hyper-radiosensitivity compared with M059K cells.A strong G2 phase arrest was observed in M059J cells post irradiation.Significant accumulation in the G2 phase in M059J cells was accompanied by apoptosis at 12 h.Altogether,the data suggested that DNA-PK may have two roles in mammalian cells after DNA damage,a role in DNA DSB repair and a second role in DNA-damaged cells to traverse a G2 checkpoint,by which DNA-PK may affect cellular sensitivity to ionizing radiation.展开更多
This study was designed to investigate the relationship of the expression of cyclin-dependent kinases (CDKs) with theeffects of all-trans retinoic acid (ATRA) on the proliferation of HL-cells. HL-60 cells were treated...This study was designed to investigate the relationship of the expression of cyclin-dependent kinases (CDKs) with theeffects of all-trans retinoic acid (ATRA) on the proliferation of HL-cells. HL-60 cells were treated with ATRA for 1-4 d. Then thecapacity of DNA Synthesis was evaluated with 3H-TdR incorporation and the expression of cyclin E, cyclin D, CDK2 and CDK4protein determined with immunocytochemical staining. In addition, the expression Of CDC2, CDK2 and CDK4 mRNA was deter-mined with in situ hybridization. It was found that ATRA suppressed the proliferation of HL-60 cells and decreased their capacityof DNA synthesis to result in a down-regulation of the expression of cyclin E, cyclin D and CDC2 without comcomittant suppressionon the expression of CDK2 and CDK4. It is concluded that the effects of ATRA on the proliferation of HL-60 cells may be relatedto the down-regulation of the expression of cyclin E, cyclin D and CDC2.展开更多
Actinolactomycin 1, a new 2-oxonanonoidal antitumor antibiotic, was isolated from the fermentation broth of Streptomyces flavoretus 18522 through a bioassay-guided separation procedure. The structure of 1 was determ...Actinolactomycin 1, a new 2-oxonanonoidal antitumor antibiotic, was isolated from the fermentation broth of Streptomyces flavoretus 18522 through a bioassay-guided separation procedure. The structure of 1 was determined as 4,7-dihydroxy-3,9-dimethyl-2-oxonanone by the spectroscopic methods. Compound 1 inhibited the proliferation of A2780, K562, HCT-15, A549 and HeLa cells with the IC50 values of 1.4 ± 0.4 μmol/L, 8.4 ± 4.7 μmol/L, 9.4 ± 2.2 μmol/L, 15.4 ± 5.6 μmol/L and 13.7 ± 2.0 μmol/L, respectively. Flow cytometric analysis indicated that 1 could inhibit the cell cycle of tsFT210, A2780 and K562 cells mainly at the G0/G1 phase and could also induce apoptosis in K562 cells.展开更多
Cellular growth,development,and differentiation are tightly controlled by a conserved biological mechanism:the cell cycle.This cycle is primarily regulated by cyclin-dependent kinase(CDK)-cyclin complexes,checkpoint k...Cellular growth,development,and differentiation are tightly controlled by a conserved biological mechanism:the cell cycle.This cycle is primarily regulated by cyclin-dependent kinase(CDK)-cyclin complexes,checkpoint kinases,and CDK inhibitors.Deregulation of the cell cycle is a hallmark of the transformation of normal cells into tumor cells.Given its importance in tumorigenesis,several cell cycle inhibitors have emerged as potential therapeutic drugs for the treatment of cancers-both as singleagent therapy and in combination with traditional cytotoxic or molecular targeting agents.In this review,we discuss the mechanisms underlying cell cycle regulation and present small-molecule anticancer drugs that are under development,including both pan-CDK inhibitors and CDK4/6-selective inhibitors.In addition,we provide an outline of some promising CDK inhibitors currently in preclinical and clinical trials that target cell cycle abnormalities in various cancers.展开更多
In any multi-cellular organism, the balance between cell division and cell death maintains a constant cell number. Both cell division cycle and cell death are highly regulated events. Whether the cell will proceed thr...In any multi-cellular organism, the balance between cell division and cell death maintains a constant cell number. Both cell division cycle and cell death are highly regulated events. Whether the cell will proceed through the cycle or not, depends upon whether the conditions required at the checkpoints during the cycle are fulfilled. In higher eucaryotic cells, such as mammalian cells, signals that arrest the cycle usually act at a G1 checkpoint. Cells that pass this restriction point are committed to complete the cycle. Regulation of the GI phase of the cell cycle is extremely complex and involves many different families of proteins such as retinoblastoma family cyclin dependent kinases, cyclins, and cyclic kinase inhibitors.展开更多
Esophageal adenocarcinoma is a major cause of cancer death in men in the developed world.Continuing poor outcomes with conventional therapies that predominantly target apoptosis pathways have lead to increasing intere...Esophageal adenocarcinoma is a major cause of cancer death in men in the developed world.Continuing poor outcomes with conventional therapies that predominantly target apoptosis pathways have lead to increasing interest in treatments that target the cell cycle.A large international effort has led to the development of a large number of inhibitors,which target cell cycle kinases,including cyclin-dependent kinases,Aurora kinases and polo-like kinase.Initial phase Ⅰ/Ⅱ trials in solid tumors have often demonstrated only modest clinical benefits of monotherapy.This may relate in part to a failure to identify the patient populations that will gain the most clinical benefit.Newer compounds lacking the side effect profile of first-generation compounds may show utility as adjunctive treatments targeted to an individual's predicted response to treatment.展开更多
AIM: To determine the effect of cis-9, trans-1l-conjugated linoleic acid ( c9, tl 1-CLA) on the cell cycle of gastric cancer cells( SGC-7901 ) and its possible mechanism in inhibition cancer growth.METHODS: Using cell...AIM: To determine the effect of cis-9, trans-1l-conjugated linoleic acid ( c9, tl 1-CLA) on the cell cycle of gastric cancer cells( SGC-7901 ) and its possible mechanism in inhibition cancer growth.METHODS: Using cell culture and immunocytochemicaltechniques, we examined the cell growth, DNA synthesis,expression of PCNA, cyclin A, B1, D1, pl6nink4a and p21clp/wafl ofSGC-7901 cells which were heated with various c9, tll-CLAconcentrations (25,50,100 and 200μnol@L-1)of c9, tll-CLA for 24and 48 h, with a negative control (0.1% ethane).RESULTS: The cell growth and DNA synthesis of SGC-7901cells were inhibited by c9, tll-CLA. SGC-7901 cells. Eightday after treatment with various concentrations of c9, tl1-CLA mentioned above, the inhibition rates were 5.92 % ,20.15 % ,75.61% and 82.44 % ,respectively and inhibitory effeotof c9, tll-CLA on DNA synthesis (except for 25 tmol/L,24h) showed significantly less 3H-TdR incorporation than thatin the negative controls (P < 0. 05 and P < 0. 01).Immunocytochemical staining demonstrated that SGC-7901cells preincubated in media supplemented with different c9,tl1-CLA concentrations at various times significantlydecreased the expressions of PCNA (the expression rateswere7.2-3.0 %,24 h and 9.1-0.9 % at 48 h, respectively),Cyclin A (l1.0-2.3 %, 24 h and 8.5-0.5 % ,48 h), B1 (4.8-1.8% at 24 h and 5.5-0.6 % at 48 h)and D1 (3.6-1.4 % at 24 hand 3.7 %-0 at 48 h) as compared with those in the negativecontrols(the expressions of PCNA, Cyclin A, B1 and D1were 6.5 % at 24h and 9.0 % at 48 h, 4.2% at 24h and5.1% at 48 h, 9.5 % at 24h and 6.0 % at 48 h,respectively)(P< 0.01), whereas the expressions of p16ink4a and p21clp/waf1,cyclin-dependent kinases inhibltors(CDKI), were increased.CONCLUSION: The cell growth and proliferation of SGC-7901cell is inhibited by c9, tll-CLA via blocking the cell cycle,with reduced expressions of cyclin A, B1 and D1 andenhanced expressions of CDKI( p16ink4a and p21cip/waf1).展开更多
Human polo-like kinases (PLK1-PLK4) have been implicated in mitotic regulation and carcinogenesis. PLK1 phosphorylates early mitotic inhibitor 1 (Emil) to ensure mitosis entry, whereas Emi2 plays a key role during...Human polo-like kinases (PLK1-PLK4) have been implicated in mitotic regulation and carcinogenesis. PLK1 phosphorylates early mitotic inhibitor 1 (Emil) to ensure mitosis entry, whereas Emi2 plays a key role during the meiotic cell cycle. Transcription factor E2F is primarily considered to regulate the G1/S transition of the cell cycle but its involvement in the regulation of mitosis has also been recently suggested. A gap still exists between the molecular basis of E2F and mitotic regulation. The present study was designed to characterize the transcriptional regulation of human PLK and Emi genes. Adenoviral overexpression of E2F1 increased PLK1 and PLK3 mRNA levels in A549 cells. A reporter gene assay revealed that the putative promoter regions of PLK1, PLK3, and PLK4 genes were responsive to activators E2F, E2F1-E2F3. We further characterized the putative promoter regions of Emil and Emi2 genes, and these could be regulated by activators E2F and E2F1-E2F4, respectively. Finally, PLK1-PLK4, Emil, and Emi2 mRNA expression levels in human adult, fetal tissues, and several cell lines indicated that each gene has a unique expression pattern but is uniquely expressed in common tissues and cells such as the testes and thymus. Collectively, these results indicate that E2F can integrate G1/S and G2/M to oscillate the cell cycle by regulating mitotic genes PLK and Emi, leading to determination of the cell fate.展开更多
This study investigated the effect and mechanism of cell cycle reentry induced by 6-hydrodopamine (6-OHDA) in PC12 cells. By using neural differentiated PC12 cells treated with 6-OHDA, the apoptosis model of dopamin...This study investigated the effect and mechanism of cell cycle reentry induced by 6-hydrodopamine (6-OHDA) in PC12 cells. By using neural differentiated PC12 cells treated with 6-OHDA, the apoptosis model of dopaminergic neurons was established. Cell viability was measured by MTT. Cell apoptosis and the distribution of cell cycle were assessed by flow cytometry. Western blot was used to detect the activation of extracellular regulator kinasel/2 (ERK1/2) pathway and the phosphorylation of retinoblastoma protein (RB). Our results showed that after PC12 cells were treated wtih 6-OHDA, the viability of PC12 cells was declined in a concentration-dependent manner. Flow cytornetry revealed that 6-OHDA could increase the apoptosis ratio of PC12 cells in a time-dependent manner. The percentage of ceils in G0/G1 phase of cell cycle was decreased and that in S phase and G2/M phase increased. Simultaneously, ERK1/2 pathway was activated and phosphorylated RB increased. It was concluded that 6-OHDA could induce cell cycle reentry of dopaminergic neurons through the activation of ERK1/2 pathway and RB phosphorylation. The aberrant cell cycle reentry contributes to the apoptosis of dopaminergic neurons.展开更多
AIM: To investigate the effect of herbal compound 861 (Cpd861) on the transforming growth factor-β1 (TGFβ1)/ activin receptor-like kinase 1 (ALK1, type Ⅰ receptor) signaling-pathway-related gene expression in the L...AIM: To investigate the effect of herbal compound 861 (Cpd861) on the transforming growth factor-β1 (TGFβ1)/ activin receptor-like kinase 1 (ALK1, type Ⅰ receptor) signaling-pathway-related gene expression in the LX-2 cell line, and the inhibitory mechanism of Cpd861 on the activation of LX-2 cells. METHODS: LX-2 cells were treated with TGFβ1 (5 ng/mL) Cpd861 (0.1 mg/mL), TGFβ1 (5 ng/mL) plus Cpd861 (5 ng/mL) for 24 h to investigate the effect of Cpd861 on the TGFβ1/ALK1 pathway. Real-time PCR was performed to examine the expression of α-SMA (α-smooth muscle actin), ALK1, Id1 (inhibitor of differentiation 1). Western blotting was carried out to measure the levels of α-SMA and phosphorylated Smad1, and immunocytochemical analysis for the expression of α-SMA. RESULTS: In LX-2 cells, TGFβ1/ALK1-pathway-related gene expression could be stimulated by TGFβ1, which led to excessive activation of the cells. Cpd861 decreased the activation of LX-2 cells by reducing the expression of α-SMA mRNA and protein expression. This effect was related to inhibition of the above TGFβ1/ALK1-pathway- related expression of genes such as Id1 and ALK1, and phosphorylation of Smad1 in LX-2 cells, even with TGFβ1 co-treatment for 24 h. CONCLUSION: Cpd861 can restrain the activation of LX-2 cells by inhibiting the TGFβ1/ALK1/Smad1 pathway.展开更多
Ethanol is a hepatotoxin. It appears that the liver is the target of ethanol induced toxicity primarily because it is the major site of ethanol metabolism. Metabolism of ethanol results in a number of biochemical chan...Ethanol is a hepatotoxin. It appears that the liver is the target of ethanol induced toxicity primarily because it is the major site of ethanol metabolism. Metabolism of ethanol results in a number of biochemical changes that are thought to mediate the toxicity associated with ethanol abuse. These include the production of acetaldehyde and reactive oxygen species, as well as an accumulation of nicotinamide adenine dinucleotide (NADH). These biochemical changes are associated with the accumulation of fat and mitochondrial dysfunction in the liver. If these changes are severe enough they can themselves cause hepatotoxicity, or they can sensitize the liver to more severe damage by other hepatotoxins. Whether liver damage is the result of ethanol metabolism or some other hepatotoxin, recovery of the liver from damage requires replacement of cells that have been destroyed. It is now apparent that ethanol metabolism not only causes hepatotoxicity but also impairs the replication of normal hepatocytes. This impairment has been shown to occur at both the G1/S, and the G2/M transitions of the cell cycle. These impairments may be the result of activation of the checkpoint kinases, which can mediate cell cycle arrest at both of these transitions. Conversely, because ethanol metabolism results in a number of biochemical changes, there may be a number of mechanisms by which ethanol metabolism impairs cellular replication. It is the goal of this article to review the mechanisms by which ethanol metabolism mediates impairment of hepatic replication.展开更多
The effect of thyrosine kinase, calmodulin and voltage-dependent Ca 2+ channel on the proliferation of hepatoma cells induced by EGF was studied. Hepatoma cell line SMMC7721 was cultured in RPMI1640 serum-free me...The effect of thyrosine kinase, calmodulin and voltage-dependent Ca 2+ channel on the proliferation of hepatoma cells induced by EGF was studied. Hepatoma cell line SMMC7721 was cultured in RPMI1640 serum-free medium. DNA synthesis rate of hepatoma cells was measured by 3H-TdR incorporation. 10 -9 mol/L EGF could significantly stimulate the proliferation of hepatoma cells (P<0.05), and this effect might be significantly inhibited by tyrosine kinase inhibitor (P<0.001). Calmodulin inhibitor W-7 had no effect on the basic phase of cultured hepatoma cells (P> 0.05), but it had very significantly inhibitory effect on the proliferation of hepatoma cells induced by EGF (P<0.001). Voltage-dependent Ca 2+ channel inhibitor Varapamil had no inhibition on the proliferation of hepatoma cells induced by EGF (P>0.05). It had no effect on the basic phase of cultured hepatoma cells (P>0.05). It is suggested that tyrosine kinase and Ca 2+-calmodulin-dependent pathway may play a critical role on the proliferation of heptoma cells induced by EGF, and voltage-dependent Ca 2+ channel is independent of the effect of EGF.展开更多
文摘Hepatocellular carcinoma(HCC)is one of the most common human cancers,and its incidence is still increasing in many countries.The prognosis of HCC patients remains poor,and identification of useful molecular prognostic markers is required.Many recent studies have shown that functional alterations of cell-cycle regulators can be observed in HCC.Among the various types of cell-cycle regulators,p16 and p27 are frequently inactivated in HCC and are considered to be potent tumor suppressors.p16,a G1-specific cell-cycle inhibitor that prevents the association of cyclindependent kinase(CDK)4 and CDK6 with cyclin D1,is frequently inactivated in HCC via CpG methylation of its promoter region.p16 may be involved in the early steps of hepatocarcinogenesis,since p16 gene methylation has been detected in subsets of pre-neoplastic liver cirrhosis patients.p27,a negative regulator of the G1-S phase transition through inhibition of the kinase activities of Cdk2/cyclin A and Cdk2/cyclin E complexes,is now considered to be an adverse prognostic factor in HCC.In some cases of HCC with increased cell proliferation,p27 is overexpressed but inactivated by sequestration into cyclin D1-CDK4-containing complexes.Since loss of p16 is closely related to functional inactivation of p27 in HCC, investigating both p16 and p27 may be useful for precise prognostic predictions in individuals with HCC.
文摘Aim: To determine the mechanisms of glucocorticoids in inhibiting advanced prostate cancer growth. Methods: The cell proliferation and cell cycle of prostate cancer DU145 cells following dexamethasone treatment were determined by proliferation assay and fluorescence-activated cell sorter. Western blot analysis was carried out to evaluate the effects of dexamethasone on phosphorylation of extracellular signal-regulated kinase (ERK)1/2 and expression of cyclin D1 in DU145 cells with or without glucocorticoid receptor (GR) antagonist RU486. Reverse transcription- polymerase chain reaction verified the expression of GR mRNA in DU145 cells. Results: Dexamethasone significantly inhibited DU 145 cell proliferation at the G0/G1 phase. Westem blot analysis showed a dramatic reduction of ERK1/2 activity and cyclin D1 expression in dexamethasone-treated cells. The decreased phosphorylation of ERK1/2 in dexamethasone-treated cells was attenuated by GR blockade. Additionally, the effects of dexamethasone in inhibiting cyclin D1 expression were altered by GR blockade. Conclusion: Dexamethasone suppresses DU145 cell proliferation and cell cycle, and the underlying mechanisms are through the inhibition of phosphorylation of ERK1/2 and cyclin D1 expression. The inhibition of ERK1/2 phosphorylation and cyclin D1 expression is attenuated by GR blockade, suggesting that GR regulates ERK1/2 and cyclin D1 pathways. These observations suggest that dexamethasone has a potential clinical application in prostate cancer therapy.
基金Supported by the Songeui Foundation of the Catholic University of Korea for Medical Research
文摘AIM: To investigate the growth inhibitory mechanism of NS-398, a selective cyclooxygenase-2 (COX-2) inhibitor, in two hepatocellular carcinoma (HCC) cell lines (HepG2 and Huh7). METHODS: HepG2 and Huh7 cells were treated with NS-398. Its effects on cell viability, cell proliferation, cell cycles, and gene expression were respectively evaluated by water-soluble tetrazolium salt (WST-1) assay, 4’-6-diamidino-2-phenylindole (DAPI) staining, flow cytometer analysis, and Western blotting, with dimethyl sulfoxide (DMSO) as positive control. RESULTS: NS-398 showed dose- and time-dependent growth-inhibitory effects on the two cell lines. Proliferating cell nuclear antigen (PCNA) expressions in HepG2 and Huh7 cells, particularly in Huh7 cells were inhibited in a time- and dose-independent manner. NS-398 caused cell cycle arrest in the G1 phase with cell accumulation in the sub-G1 phase in HepG2 and Huh7 cell lines. No evidence of apoptosis was observed in two cell lines. CONCLUSION: NS-398 reduces cell proliferation by inducing cell cycle arrest in HepG2 and Huh7 cell lines, and COX-2 inhibitors may have potent chemoprevention effects on human hepatocellular carcinoma.
基金supported by grants from the National Key Research and Development Program of China(2021YFF1201300)the National Natural Science Foundation of China(81872280,82073094)+2 种基金the CAMS Innovation Fund for Medical Sciences(CIFMS)(2021-I2M-1-014)the Open Issue of State Key Laboratory of Molecular Oncology(SKL-KF-2021-16)the Independent Issue of State Key Laboratory of Molecular Oncology(SKL-2021-16).
文摘Background:The cell cycle is at the center of cellular activities and is orchestrated by complex regulatory mechanisms,among which transcriptional regulation is one of the most important components.Alternative splicing dramatically expands the regulatory network by producing transcript isoforms of genes to exquisitely control the cell cycle.However,the patterns of transcript isoform expression in the cell cycle are unclear.Therapies targeting cell cycle checkpoints are commonly used as anticancer therapies,but none of them have been designed or evaluated at the alternative splicing transcript level.The utility of these transcripts as markers of cell cycle-related drug sensitivity is still unknown,and studies on the expression patterns of cell cycle-targeting drug-related transcripts are also rare.Methods:To explore alternative splicing patterns during cell cycle progression,we performed sequential transcriptomic assays following cell cycle synchronization in colon cancer HCT116 and breast cancer MDA-MB-231 cell lines,using flow cytometry and reference cell cycle transcripts to confirm the cell cycle phases of samples,and we developed a new algorithm to describe the periodic patterns of transcripts fluctuating during the cell cycle.Genomics of Drug Sensitivity in Cancer(GDSC)drug sensitivity datasets and Cancer Cell Line Encyclopedia(CCLE)transcript datasets were used to assess the correlation of genes and their transcript isoforms with drug sensitivity.We identified transcripts associated with typical drugs targeting cell cycle by determining correlation coefficients.Cytotoxicity assays were used to confirm the effect of ENST00000257904 against cyclin dependent kinase 4/6(CDK4/6)inhibitors.Finally,alternative splicing transcripts associated with mitotic(M)phase arrest were analyzed using an RNA synthesis inhibition assay and transcriptome analysis.Results:We established high-resolution transcriptome datasets of synchronized cell cycle samples from colon cancer HCT116 and breast cancer MDA-MB-231 cells.The results of the cell cycle assessment showed that 43,326,41,578 and 29,244 transcripts were found to be periodically expressed in HeLa,HCT116 and MDA-MB-231 cells,respectively,among which 1280 transcripts showed this expression pattern in all three cancer cell lines.Drug sensitivity assessments showed that a large number of these transcripts displayed a higher correlation with drug sensitivity than their corresponding genes.Cell cycle-related drug screening showed that the level of the CDK4 transcript ENST00000547281 was more significantly associated with the resistance of cells to CDK4/6 inhibitors than the level of the CDK4 reference transcript ENST00000257904.The transcriptional inhibition assay following M phase arrest further confirmed the M-phase-specific expression of the splicing transcripts.Combined with the cell cycle-related drug screening,the results also showed that a set of periodic transcripts,for example,ENST00000314392(a dolichylphosphate mannosyltransferase polypeptide 2 isoform transcript),was more associated with drug sensitivity than the levels of their corresponding gene transcripts.Conclusions:In summary,we identified a panel of cell cycle-related periodic transcripts and found that the levels of transcripts of drug target genes showed different values for predicting drug sensitivity,providing novel insights into alternative splicing-related drug development and evaluation.
文摘Aurora kinases play an important role in the cell cycle. These enzymes help establish mitotic spindles by directing centrosome duplication and separation and by regulating the spindle assembly checkpoint thereby helping control cytokinesis. An over-expression of aurora kinases has been reported in a variety of human tumors. In this study, we identified the expression of aurora-A and aurora-B kinases in canine malignant lymphoid cells. We also evaluated the effects of the aurora kinase inhibitor (ZM447439), and found that this inhibitor decreases cell viability, increases DNA content change, and leads to apoptosis in canine B- and T-cell lymphoid cell lines. The lymphotoxicity induced by ZM447439 in these canine lymphoid cell lines suggests that further in vivo evaluation of aurora kinase inhibitors as a potential treatment for canine malignant lymphoid tumors is warranted.
基金Supported by the National Natural Science Foundation of China,No.81702777Natural Science Foundation of Guangdong Province,No.2015A030310053
文摘BACKGROUND Growth arrest-specific gene 2(GAS2)plays a role in modulating in reversible growth arrest cell cycle,apoptosis,and cell survival.GAS2 protein is universally expressed in most normal tissues,particularly in the liver,but is depleted in some tumor tissues.However,the functional mechanisms of GAS2 in hepatocellular carcinoma(HCC)are not fully defined.AIM To investigate the function and mechanism of GAS2 in HCC.METHODS GAS2 expression in clinic liver and HCC specimens was analyzed by real-time PCR and western blotting.Cell proliferation was analyzed by counting,MTS,and colony formation assays.Cell cycle analysis was performed by flow cytometry.Cell apoptosis was investigated by Annexin V apoptosis assay and western blotting.RESULTS GAS2 protein expression was lower in HCC than in normal tissues.Overexpression of GAS2 inhibited the proliferation of HCC cells with wide-type p53,while knockdown of GAS2 promoted the proliferation of hepatocytes(P<0.05).Furthermore,GAS2 overexpression impeded the G1-to-S cell cycle transition and arrested more G1 cells,particularly the elevation of sub G1(P<0.01).Apoptosis induced by GAS2 was dependent on p53,which was increased by etoposide addition.The expression of p53 and apoptosis markers was further enhanced when GAS2 was upregulated,but became diminished upon downregulation of GAS2.In the clinic specimen,GAS2 was downregulated in more than 60%of HCCs.The average fold changes of GAS2 expression in tumor tissues were significantly lower than those in paired non-tumor tissues(P<0.05).CONCLUSION GAS2 plays a vital role in HCC cell proliferation and apoptosis,possibly by regulating the cell cycle and p53-dependent apoptosis pathway.
基金This study was supported by a grant from the National Nature Science Foundation of China(No.30230140,30400142)
文摘Background:Astrocytes become reactive following many types of CNS injuries.Excessive astrogliosis is detrimental and contributes to neuronal damage.We sought to determine whether inhibition of cell cycle could decrease the proliferation of astroglial cells and therefore reduce excessive gliosis and glial scar formation after focal ischemia.Methods:Cerebral infarction model was induced by photothrombosis method.Rats were examined using MRI,and lesion volumes were estimated on day 3 post-infarction.The expression of glial fibrillary acidic protein(GFAP) and proliferating cell nuclear antigen(PCNA) was observed by immunofluorescence staining.Protein levels for GFAP,PCNA,Cyclin A and Cyclin B1 were determined by Western blot analysis from the ischemic and sham animals sacrificed at 3,7,30 days after operation.Results:Cell cycle inhibitor olomoucine significantly suppressed GFAP and PCNA expression and reduced lesion volume after cerebral ischemia.In parallel studies,we found dense astroglial scar in boundary zone of vehicle-treated rats at 7 and 30 days.Olomoucine can markedly attenuate astroglial scar formation.Western blot analysis showed increased protein levels of GFAP,PCNA,Cyclin A and Cyclin B1 after ischemia,which was reduced by olomoucine treatment.Conclusion: Our results suggested that astroglial activation,proliferation and subsequently astroglial scar formation could be partially inhibited by regulation of cell cycle.Cell cycle modulation thereby provides a potential promising strategy to treat cerebral ischemia.
基金Supported by National Natural Science Foundation of China (10675151)Western Talent Program of Chinese Academy of Sciences (0860260XBO)
文摘In this paper,we study the ability of DNA-PK-deficient(M059J) and -proficient(M059K) cells to undergo the rate of cellular proliferation,cell cycle distribution and apoptosis after 10 Gy X-ray irradiation,and the role of DNA-PK in radiosensitivity.The results showed that M059J cells exhibited hyper-radiosensitivity compared with M059K cells.A strong G2 phase arrest was observed in M059J cells post irradiation.Significant accumulation in the G2 phase in M059J cells was accompanied by apoptosis at 12 h.Altogether,the data suggested that DNA-PK may have two roles in mammalian cells after DNA damage,a role in DNA DSB repair and a second role in DNA-damaged cells to traverse a G2 checkpoint,by which DNA-PK may affect cellular sensitivity to ionizing radiation.
文摘This study was designed to investigate the relationship of the expression of cyclin-dependent kinases (CDKs) with theeffects of all-trans retinoic acid (ATRA) on the proliferation of HL-cells. HL-60 cells were treated with ATRA for 1-4 d. Then thecapacity of DNA Synthesis was evaluated with 3H-TdR incorporation and the expression of cyclin E, cyclin D, CDK2 and CDK4protein determined with immunocytochemical staining. In addition, the expression Of CDC2, CDK2 and CDK4 mRNA was deter-mined with in situ hybridization. It was found that ATRA suppressed the proliferation of HL-60 cells and decreased their capacityof DNA synthesis to result in a down-regulation of the expression of cyclin E, cyclin D and CDC2 without comcomittant suppressionon the expression of CDK2 and CDK4. It is concluded that the effects of ATRA on the proliferation of HL-60 cells may be relatedto the down-regulation of the expression of cyclin E, cyclin D and CDC2.
文摘Actinolactomycin 1, a new 2-oxonanonoidal antitumor antibiotic, was isolated from the fermentation broth of Streptomyces flavoretus 18522 through a bioassay-guided separation procedure. The structure of 1 was determined as 4,7-dihydroxy-3,9-dimethyl-2-oxonanone by the spectroscopic methods. Compound 1 inhibited the proliferation of A2780, K562, HCT-15, A549 and HeLa cells with the IC50 values of 1.4 ± 0.4 μmol/L, 8.4 ± 4.7 μmol/L, 9.4 ± 2.2 μmol/L, 15.4 ± 5.6 μmol/L and 13.7 ± 2.0 μmol/L, respectively. Flow cytometric analysis indicated that 1 could inhibit the cell cycle of tsFT210, A2780 and K562 cells mainly at the G0/G1 phase and could also induce apoptosis in K562 cells.
文摘Cellular growth,development,and differentiation are tightly controlled by a conserved biological mechanism:the cell cycle.This cycle is primarily regulated by cyclin-dependent kinase(CDK)-cyclin complexes,checkpoint kinases,and CDK inhibitors.Deregulation of the cell cycle is a hallmark of the transformation of normal cells into tumor cells.Given its importance in tumorigenesis,several cell cycle inhibitors have emerged as potential therapeutic drugs for the treatment of cancers-both as singleagent therapy and in combination with traditional cytotoxic or molecular targeting agents.In this review,we discuss the mechanisms underlying cell cycle regulation and present small-molecule anticancer drugs that are under development,including both pan-CDK inhibitors and CDK4/6-selective inhibitors.In addition,we provide an outline of some promising CDK inhibitors currently in preclinical and clinical trials that target cell cycle abnormalities in various cancers.
文摘In any multi-cellular organism, the balance between cell division and cell death maintains a constant cell number. Both cell division cycle and cell death are highly regulated events. Whether the cell will proceed through the cycle or not, depends upon whether the conditions required at the checkpoints during the cycle are fulfilled. In higher eucaryotic cells, such as mammalian cells, signals that arrest the cycle usually act at a G1 checkpoint. Cells that pass this restriction point are committed to complete the cycle. Regulation of the GI phase of the cell cycle is extremely complex and involves many different families of proteins such as retinoblastoma family cyclin dependent kinases, cyclins, and cyclic kinase inhibitors.
基金Supported by UK National Institute of Health Research/Cancer Research Network and Research and Development Department of Wrightington Wigan and Leigh NHS Foundation Trust (to Ang YS)Wrightington Wigan and Leigh NHS Foundation Trust Cancer Therapy Fund (to Dibb M)
文摘Esophageal adenocarcinoma is a major cause of cancer death in men in the developed world.Continuing poor outcomes with conventional therapies that predominantly target apoptosis pathways have lead to increasing interest in treatments that target the cell cycle.A large international effort has led to the development of a large number of inhibitors,which target cell cycle kinases,including cyclin-dependent kinases,Aurora kinases and polo-like kinase.Initial phase Ⅰ/Ⅱ trials in solid tumors have often demonstrated only modest clinical benefits of monotherapy.This may relate in part to a failure to identify the patient populations that will gain the most clinical benefit.Newer compounds lacking the side effect profile of first-generation compounds may show utility as adjunctive treatments targeted to an individual's predicted response to treatment.
基金the National Natural Science Foundation of China,No.39870661
文摘AIM: To determine the effect of cis-9, trans-1l-conjugated linoleic acid ( c9, tl 1-CLA) on the cell cycle of gastric cancer cells( SGC-7901 ) and its possible mechanism in inhibition cancer growth.METHODS: Using cell culture and immunocytochemicaltechniques, we examined the cell growth, DNA synthesis,expression of PCNA, cyclin A, B1, D1, pl6nink4a and p21clp/wafl ofSGC-7901 cells which were heated with various c9, tll-CLAconcentrations (25,50,100 and 200μnol@L-1)of c9, tll-CLA for 24and 48 h, with a negative control (0.1% ethane).RESULTS: The cell growth and DNA synthesis of SGC-7901cells were inhibited by c9, tll-CLA. SGC-7901 cells. Eightday after treatment with various concentrations of c9, tl1-CLA mentioned above, the inhibition rates were 5.92 % ,20.15 % ,75.61% and 82.44 % ,respectively and inhibitory effeotof c9, tll-CLA on DNA synthesis (except for 25 tmol/L,24h) showed significantly less 3H-TdR incorporation than thatin the negative controls (P < 0. 05 and P < 0. 01).Immunocytochemical staining demonstrated that SGC-7901cells preincubated in media supplemented with different c9,tl1-CLA concentrations at various times significantlydecreased the expressions of PCNA (the expression rateswere7.2-3.0 %,24 h and 9.1-0.9 % at 48 h, respectively),Cyclin A (l1.0-2.3 %, 24 h and 8.5-0.5 % ,48 h), B1 (4.8-1.8% at 24 h and 5.5-0.6 % at 48 h)and D1 (3.6-1.4 % at 24 hand 3.7 %-0 at 48 h) as compared with those in the negativecontrols(the expressions of PCNA, Cyclin A, B1 and D1were 6.5 % at 24h and 9.0 % at 48 h, 4.2% at 24h and5.1% at 48 h, 9.5 % at 24h and 6.0 % at 48 h,respectively)(P< 0.01), whereas the expressions of p16ink4a and p21clp/waf1,cyclin-dependent kinases inhibltors(CDKI), were increased.CONCLUSION: The cell growth and proliferation of SGC-7901cell is inhibited by c9, tll-CLA via blocking the cell cycle,with reduced expressions of cyclin A, B1 and D1 andenhanced expressions of CDKI( p16ink4a and p21cip/waf1).
文摘Human polo-like kinases (PLK1-PLK4) have been implicated in mitotic regulation and carcinogenesis. PLK1 phosphorylates early mitotic inhibitor 1 (Emil) to ensure mitosis entry, whereas Emi2 plays a key role during the meiotic cell cycle. Transcription factor E2F is primarily considered to regulate the G1/S transition of the cell cycle but its involvement in the regulation of mitosis has also been recently suggested. A gap still exists between the molecular basis of E2F and mitotic regulation. The present study was designed to characterize the transcriptional regulation of human PLK and Emi genes. Adenoviral overexpression of E2F1 increased PLK1 and PLK3 mRNA levels in A549 cells. A reporter gene assay revealed that the putative promoter regions of PLK1, PLK3, and PLK4 genes were responsive to activators E2F, E2F1-E2F3. We further characterized the putative promoter regions of Emil and Emi2 genes, and these could be regulated by activators E2F and E2F1-E2F4, respectively. Finally, PLK1-PLK4, Emil, and Emi2 mRNA expression levels in human adult, fetal tissues, and several cell lines indicated that each gene has a unique expression pattern but is uniquely expressed in common tissues and cells such as the testes and thymus. Collectively, these results indicate that E2F can integrate G1/S and G2/M to oscillate the cell cycle by regulating mitotic genes PLK and Emi, leading to determination of the cell fate.
基金supported by a grant from National Natu-ral Sciences Foundation of China (No. 30570627).
文摘This study investigated the effect and mechanism of cell cycle reentry induced by 6-hydrodopamine (6-OHDA) in PC12 cells. By using neural differentiated PC12 cells treated with 6-OHDA, the apoptosis model of dopaminergic neurons was established. Cell viability was measured by MTT. Cell apoptosis and the distribution of cell cycle were assessed by flow cytometry. Western blot was used to detect the activation of extracellular regulator kinasel/2 (ERK1/2) pathway and the phosphorylation of retinoblastoma protein (RB). Our results showed that after PC12 cells were treated wtih 6-OHDA, the viability of PC12 cells was declined in a concentration-dependent manner. Flow cytornetry revealed that 6-OHDA could increase the apoptosis ratio of PC12 cells in a time-dependent manner. The percentage of ceils in G0/G1 phase of cell cycle was decreased and that in S phase and G2/M phase increased. Simultaneously, ERK1/2 pathway was activated and phosphorylated RB increased. It was concluded that 6-OHDA could induce cell cycle reentry of dopaminergic neurons through the activation of ERK1/2 pathway and RB phosphorylation. The aberrant cell cycle reentry contributes to the apoptosis of dopaminergic neurons.
文摘AIM: To investigate the effect of herbal compound 861 (Cpd861) on the transforming growth factor-β1 (TGFβ1)/ activin receptor-like kinase 1 (ALK1, type Ⅰ receptor) signaling-pathway-related gene expression in the LX-2 cell line, and the inhibitory mechanism of Cpd861 on the activation of LX-2 cells. METHODS: LX-2 cells were treated with TGFβ1 (5 ng/mL) Cpd861 (0.1 mg/mL), TGFβ1 (5 ng/mL) plus Cpd861 (5 ng/mL) for 24 h to investigate the effect of Cpd861 on the TGFβ1/ALK1 pathway. Real-time PCR was performed to examine the expression of α-SMA (α-smooth muscle actin), ALK1, Id1 (inhibitor of differentiation 1). Western blotting was carried out to measure the levels of α-SMA and phosphorylated Smad1, and immunocytochemical analysis for the expression of α-SMA. RESULTS: In LX-2 cells, TGFβ1/ALK1-pathway-related gene expression could be stimulated by TGFβ1, which led to excessive activation of the cells. Cpd861 decreased the activation of LX-2 cells by reducing the expression of α-SMA mRNA and protein expression. This effect was related to inhibition of the above TGFβ1/ALK1-pathway- related expression of genes such as Id1 and ALK1, and phosphorylation of Smad1 in LX-2 cells, even with TGFβ1 co-treatment for 24 h. CONCLUSION: Cpd861 can restrain the activation of LX-2 cells by inhibiting the TGFβ1/ALK1/Smad1 pathway.
基金Supported by the National Institutes of Health Grant RO1 AA11291 and the Department of Veterans Affairs
文摘Ethanol is a hepatotoxin. It appears that the liver is the target of ethanol induced toxicity primarily because it is the major site of ethanol metabolism. Metabolism of ethanol results in a number of biochemical changes that are thought to mediate the toxicity associated with ethanol abuse. These include the production of acetaldehyde and reactive oxygen species, as well as an accumulation of nicotinamide adenine dinucleotide (NADH). These biochemical changes are associated with the accumulation of fat and mitochondrial dysfunction in the liver. If these changes are severe enough they can themselves cause hepatotoxicity, or they can sensitize the liver to more severe damage by other hepatotoxins. Whether liver damage is the result of ethanol metabolism or some other hepatotoxin, recovery of the liver from damage requires replacement of cells that have been destroyed. It is now apparent that ethanol metabolism not only causes hepatotoxicity but also impairs the replication of normal hepatocytes. This impairment has been shown to occur at both the G1/S, and the G2/M transitions of the cell cycle. These impairments may be the result of activation of the checkpoint kinases, which can mediate cell cycle arrest at both of these transitions. Conversely, because ethanol metabolism results in a number of biochemical changes, there may be a number of mechanisms by which ethanol metabolism impairs cellular replication. It is the goal of this article to review the mechanisms by which ethanol metabolism mediates impairment of hepatic replication.
文摘The effect of thyrosine kinase, calmodulin and voltage-dependent Ca 2+ channel on the proliferation of hepatoma cells induced by EGF was studied. Hepatoma cell line SMMC7721 was cultured in RPMI1640 serum-free medium. DNA synthesis rate of hepatoma cells was measured by 3H-TdR incorporation. 10 -9 mol/L EGF could significantly stimulate the proliferation of hepatoma cells (P<0.05), and this effect might be significantly inhibited by tyrosine kinase inhibitor (P<0.001). Calmodulin inhibitor W-7 had no effect on the basic phase of cultured hepatoma cells (P> 0.05), but it had very significantly inhibitory effect on the proliferation of hepatoma cells induced by EGF (P<0.001). Voltage-dependent Ca 2+ channel inhibitor Varapamil had no inhibition on the proliferation of hepatoma cells induced by EGF (P>0.05). It had no effect on the basic phase of cultured hepatoma cells (P>0.05). It is suggested that tyrosine kinase and Ca 2+-calmodulin-dependent pathway may play a critical role on the proliferation of heptoma cells induced by EGF, and voltage-dependent Ca 2+ channel is independent of the effect of EGF.