Hydrangea serrata extract exerts tumor inhibitory activity against hepatocellular carcinoma HepG2 cells via inducing p27/CDK2-mediated cell cycle arrest and apoptosis

Objective:To examine the inhibitory effect of Hydrangea serrata extract against hepatocellular carcinoma HepG2 cells and its underlying mechanisms.Methods:The effects of Hydrangea serrata extract on growth inhibition of tumor cells and spheroids were assessed using MTT and 3D culture assays.Quantitative real-time PCR and Western blot analyses were employed to investigate the changes in mRNA and protein expression levels of molecules related to cell cycle and apoptosis.Results:Hydrangea serrata extract effectively inhibited the growth of both tumor cells and spheroids.The extract also significantly upregulated p27 mRNA expression and downregulated CDK2 mRNA expression,leading to cell cycle arrest.Moreover,increased BAX/Bcl-2 ratio as well as caspase-9 and-3 were observed after treatment with Hydrangea serrata extract,indicating the induction of tumor cell apoptosis.Conclusions:Hydrangea serrata extract has the potential to alleviate tumors by effectively modulating cell-cycle-related gene expressions and inducing apoptosis,thereby inhibiting tumor growth.

The MORC2 p.S87L mutation reduces proliferation of pluripotent stem cells derived from a patient with the spinal muscular atrophy-like phenotype by inhibiting proliferation-related signaling pathways

Mutations in the microrchidia CW-type zinc finger protein 2(MORC2)gene are the causative agent of Charcot-Marie-Tooth disease type 2Z(CMT2Z),and the hotspot mutation p.S87L is associated with a more seve re spinal muscular atrophy-like clinical phenotype.The aims of this study were to determine the mechanism of the severe phenotype caused by the MORC2 p.S87L mutation and to explore potential treatment strategies.Epithelial cells were isolated from urine samples from a spinal muscular atrophy(SMA)-like patient[MORC2 p.S87L),a CMT2Z patient[MORC2 p.Q400R),and a healthy control and induced to generate pluripotent stem cells,which were then differentiated into motor neuron precursor cells.Next-generation RNA sequencing followed by KEGG pathway enrichment analysis revealed that differentially expressed genes involved in the PI3K/Akt and MAP K/ERK signaling pathways were enriched in the p.S87L SMA-like patient group and were significantly downregulated in induced pluripotent stem cells.Reduced proliferation was observed in the induced pluripotent stem cells and motor neuron precursor cells derived from the p.S87L SMA-like patient group compared with the CMT2Z patient group and the healthy control.G0/G1 phase cell cycle arrest was observed in induced pluripotent stem cells derived from the p.S87L SMA-like patient.MORC2 p.S87Lspecific antisense oligonucleotides(p.S87L-ASO-targeting)showed significant efficacy in improving cell prolife ration and activating the PI3K/Akt and MAP K/ERK pathways in induced pluripotent stem cells.Howeve r,p.S87L-ASO-ta rgeting did not rescue prolife ration of motor neuron precursor cells.These findings suggest that downregulation of the PI3K/Akt and MAP K/ERK signaling pathways leading to reduced cell proliferation and G0/G1 phase cell cycle arrest in induced pluripotent stem cells might be the underlying mechanism of the severe p.S87L SMA-like phenotype.p.S87L-ASO-targeting treatment can alleviate disordered cell proliferation in the early stage of pluripotent stem cell induction.

Combinatorial effect of diclofenac with piperine and D-limonene on inducing apoptosis and cell cycle arrest of breast cancer cells

Objective:To investigate the potential synergistic activity of diclofenac with piperine and D-limonene in inducing apoptosis and cell cycle arrest in breast cancer MCF-7 cells.Methods:Molecular docking study was conducted to evaluate the binding affinity of diclofenac with piperine and D-limonene against p53,Bax,and Bcl-2.The MTT assay was used to determine IC50,and the Chou-Talay method was used to determine the synergistic concentration of the combination treatment of diclofenac plus piperine and diclofenac plus D-limonene.Apoptosis detection,cell cycle arrest,reactive oxygen species production,and mitochondrial membrane potential were also investigated.Results:Diclofenac,piperine,and D-limonene showed potent binding affinity for p53,Bax,and Bcl-2.Diclofenac plus piperine and diclofenac plus D-limonene enhanced the formation of reactive oxygen species,which also had an effect on the mitochondrial membrane’s integrity and caused DNA fragmentation.Diclofenac plus piperine and diclofenac plus D-limonene arrested the cells in the sub-G0phase while drastically lowering the percentage of cells in the G2/M phase.Furthermore,the elevated apoptosis in the combined therapy was confirmed by annexin V/propidium iodide staining.Conclusions:The combined therapy prominently enhanced the antiproliferative and apoptotic effects on MCF-7 cells compared with treatment with diclofenac,piperine,and D-limonene alone.

Wild pink bayberry free phenolic extract induces mitochondria-dependent apoptosis and G0/G1 cell cycle arrest through p38/MAPK and PI3K/Akt pathway in MDA-MB-231 cancer cells

Polyphenol-rich foods have been shown to be good for cancer prevention as powerful antioxidants. In this study, the mechanisms of wild pink bayberry free phenolic extract(WPBFE)inhibiting the proliferation and inducing apoptotic of MDA-MB-231 breast cancer cells was examined. The main phenolic acids and flavonols in WPBFE were gallic acid((18.83 ± 0.44)μg/g FW)and myricetin((1.52 ± 0.05)μg/g FW), respectively. The maximum inhibition rate of WPBFE at non-cytotoxicity dose(below 80 mg/mL)was 81%. Western blotting analysis showed that WPBFE could cause the arrest of cell cycle in G0/G1 phase by down-regulating expression levels of PCNA, CDK4, cyclin D1 and up-regulating the expression level of p21. Meanwhile, WPBFE induced apoptosis through initiating the mitochondrial death pathway by up-regulating cleaved caspase-3 and enhancing the ratio of Bax/Bcl-2, with the maximum expression levels of 1.29 and 2.03 folds that of control group, respectively. Further study of the upstream protein, we found that WPBFE down-regulated TRAF2, while upregulated p-ASK1, p-p38 and p-p53. Furthermore, WPBFE could down-regulate the expression of p-PI3K and p-Akt. These observations indicated that WPBFE might play an anticancer role through regulating the p38 MAPK together with PI3K/Akt pathway.

Novel coumarone-derived(S,E)-4-(4-fluorobenzylidene)-3-phenylchroman-3-ol inhibits muscle-invasive bladder cancer cells by repressing the S and G2 cell cycle phases

Background:This study aimed to select compounds with unique inhibitory effects on muscle-invasive bladder cancer(MIBC)from coumarone derivatives with similar parent nuclear structures and to reveal their tumor-suppressive effects using various approaches.Methods:Bladder cancer cell lines SW780 and T24,as well as human normal bladder epithelial cell line SV-HUC-1 were selected as the study model,and these urinary system cells were co-incubated with various concentrations of(S,E)-4-(4-methylbenzylidene)-3-phenylchroman-3-ol,(S,E)-4-(4-isocyanobenzylidene)-3-phenylchroman-3-ol,(S,E)-4-(4-fluorobenzylidene)-3-phenylchroman-3-ol(FPO),and(S,E)-3-phenyl-4-(4-(trifluoromethoxy)benzylidene)chroman-3-ol.Cell activity was detected using cell counting kit-8.FPO showed the strongest inhibitory effect on MIBC cells;therefore,it was selected for further experiments.We monitored the FPO-induced T24 cell morphological changes with an inverted microscope.The FPO-inhibited migration of T24 cells was examined using a cell scratch assay.We detected the clonogenic ability of T24 cells through a clone formation test and evaluated their proliferative ability using a 5-ethynyl-2’-deoxyuridine fluorescence staining kit.The inhibitory effect of FPO against the cell cycle was monitored using flow cytometry,and its suppressive effect on the DNA replication ability of T24 cells was detected using double fluorescence staining(Ki67 and phalloidin).Results:Among the four candidate coumarone derivatives,FPO showed the most significant inhibitory effect on MIBC cells and was less toxic to normal urothelial cells.FPO inhibited T24 cell growth in time and dose-dependent manners(the half-inhibitory concentration is 8μM).FPO significantly repressed the proliferation,migration,and clonogenic ability of bladder cancer T24 cells.Cell mobility was significantly inhibited by FPO:30μM FPO almost completely repressed migration occurred at after 24 h treatment.Moreover,FPO significantly suppressed the clonogenicity of bladder cancer cells in a dose-dependent manner.Mechanistically,FPO targeted the cell cycle,arresting the S and G2 phases on bladder cancer T24 cells.Conclusion:We discovered a novel anticancer chemical,FPO,and proposed a potential mechanism,through which it suppresses MIBC T24 cells by repressing the cell cycle in the S and G2 phases.This study contributes to the development of novel anticancer drugs for MIBC.

Antitumor Effect of Apcin on Endometrial Carcinoma via p21-Mediated Cell Cycle Arrest and Apoptosis

Objective Endometrial carcinoma(EC)is a prevalent gynecological malignancy characterized by increasing incidence and mortality rates.This underscores the critical need for novel therapeutic targets.One such potential target is cell division cycle 20(CDC20),which has been implicated in oncogenesis.This study investigated the effect of the CDC20 inhibitor Apcin on EC and elucidated the underlying mechanism involved.Methods The effects of Apcin on EC cell proliferation,apoptosis,and the cell cycle were evaluated using CCK8 assays and flow cytometry.RNA sequencing(RNA-seq)was subsequently conducted to explore the underlying molecular mechanism,and Western blotting and coimmunoprecipitation were subsequently performed to validate the results.Animal studies were performed to evaluate the antitumor effects in vivo.Bioinformatics analysis was also conducted to identify CDC20 as a potential therapeutic target in EC.Results Treatment with Apcin inhibited proliferation and induced apoptosis in EC cells,resulting in cell cycle arrest.Pathways associated with apoptosis and the cell cycle were activated following treatment with Apcin.Notably,Apcin treatment led to the upregulation of the cell cycle regulator p21,which was verified to interact with CDC20 and consequently decrease the expression of downstream cyclins in EC cells.In vivo experiments confirmed that Apcin treatment significantly impeded tumor growth.Higher CDC20 expression was observed in EC tissue than in nonmalignant tissue,and increased CDC20 expression in EC patients was associated with shorter overall survival and progress free interval.Conclusion CDC20 is a novel molecular target in EC,and Apcin could be developed as a candidate antitumor drug for EC treatment.

A comparative in vitro study on the effect of SGLT2 inhibitors on chemosensitivity to doxorubicin in MCF-7 breast cancer cells

Cancer frequently develops resistance to the majority of chemotherapy treatments.This study aimed to examine the synergistic cytotoxic and antitumor effects of SGLT2 inhibitors,specifically Canagliflozin(CAN),Dapagliflozin(DAP),Empagliflozin(EMP),and Doxorubicin(DOX),using in vitro experimentation.The precise combination of CAN+DOX has been found to greatly enhance the cytotoxic effects of doxorubicin(DOX)in MCF-7 cells.Interestingly,it was shown that cancer cells exhibit an increased demand for glucose and ATP in order to support their growth.Notably,when these medications were combined with DOX,there was a considerable inhibition of glucose consumption,as well as reductions in intracellular ATP and lactate levels.Moreover,this effect was found to be dependent on the dosages of the drugs.In addition to effectively inhibiting the cell cycle,the combination of CAN+DOX induces substantial modifications in both cell cycle and apoptotic gene expression.This work represents the initial report on the beneficial impact of SGLT2 inhibitor medications,namely CAN,DAP,and EMP,on the responsiveness to the anticancer properties of DOX.The underlying molecular mechanisms potentially involve the suppression of the function of SGLT2.

Sciadopitysin exerts anticancer effects on HepG2 hepatocellular carcinoma cells by regulating reactive oxygen species-mediated signaling pathways

Objectives:Sciadopitysin(SP)is aflavonoid in Ginkgo biloba that exhibits various pharmacological activities.This study aimed to investigate its antitumor effects and the underlying molecular mechanism of SP in hepatocellular carcinoma(HCC)cells.Methods:Network pharmacology was used for target prediction analysis.Cell Counting Kit-8(CCK-8)assay was used to test the cell viability.Flow cytometry was used to test the cell cycle distribution,apoptosis status,and reactive oxygen species(ROS)levels.Transwell and wound-healing assay was used to test the migration effect of SP on HepG2 cells.Western Blot assay was used to test the expression levels of proteins.Results:Network pharmacology analysis results showed that the mitogen-activated protein kinase(MAPK)and other signaling pathways are involved in the SP anti-HCC biological process.CCK-8 assay results demonstrated that SP showed an obvious killing effect on three types of HCC cells and low cytotoxic effect on normal cells.Western Blot andflow cytometry results showed that SP regulated MAPK/signal transducer and activator of transcription 3(STAT3)/nuclear factor kappa-B(NF-κB)signaling pathway to induce mitochondrion-dependent apoptosis in HepG2 cells.Additionally,SP can arrest the G0/G1 phase cell cycle via the protein kinase B(AKT)/p21/p27/cyclin-dependent kinase(CDK)/Cyclin signaling pathway.Wound healing and transwell assays showed that SP inhibited cell motility and invasion through the AKT/glycogen synthase kinase3β(GSK-3β)/vimentin/β-catenin signaling pathway.Conclusion:Thesefindings demonstrated that SP induced mitochondrion-dependent apoptosis,arrested cell cycle in the G0/G1 phase,and inhibited cell migration by regulating the ROS-mediated signaling pathway in HepG2 cells.Thus,SP could serve as a therapeutic agent for the treatment of human HCC.

Meiotic nuclear divisions 1 suppresses the proliferation and invasion of pancreatic cancer cells via regulating H2A.X variant histone

Introduction:Among all malignant tumors of the digestive system,pancreatic carcinoma exhibits the highest mortality rate.Currently,prevention and effective treatment are urgent issues that need to be addressed.Methods:The study focused on meiotic nuclear divisions 1(MND1),integrating data from the Gene Expression Profiling Interactive Analysis(GEPIA)database with prognostic survival analysis.Simultaneously,experiments at cellular level were employed to demonstrate the effect of MND1 on the proliferation and migration of PC.The small-molecule inhibitor of MND1 was used to suppress the migration of PC cells by knocking down MND1 using small interfering RNA(siRNA)in Patu-8988 and Panc1 cell lines.Results:The results of Cell Counting Kit-8 indicated that the suppression of MND1 resulted in a decrease in cell proliferation.Wound healing and Transwell assays revealed that MND1 knockdown reduced cell migration and invasion.Flow cytometry revealed that inhibiting MND1 hindered the cell cycle.Furthermore,MND1 could stimulate the proliferation,migration,and invasion of Patu-8988 and Panc1 cells by increasing the expression of MND1.Notably,MND1 had a positive effect on H2AFX expression in PC cells.Elevated MND1 expression suggests the low overall survival rate of individuals diagnosed with PC.Conclusion:These findings suggest that MND1 has the potential to be a gene with the ability to accurately diagnose and treat PC.

Down-regulation of Hsp90 could change cell cycle distribution and increase drug sensitivity of tumor cells

:AIM To construct Hsp90 antisense RNAeukaryotic expression vector, transfect it intoSGC7901 and SGC7901/VCR of MDR-type humangastric cancer cell lines, HCC7402 of humanhepatic cancer and Eel09 of human esophagealcancer cell lines, and to study the cell cycledistribution of the gene transected cells andtheir response to chemotherapeutic drugs.METHODS A I .03kb cDNA sequence of Hsp90Pwas obtained from the primary plasmid phHsp90by EcoR 1 and BamH I nuclease digestion andwas cloned to the EcoR 1 and BamH 1 site ofthe pcDNA by T4DNA ligase and an antisenseorientation of Hsp900 expression vector wasconstructed. The constructs were transfectedwith lipofectamine and positive clones wereselected with G418. The expression of RNA wasdetermined with dot blotting and RNaseprotection assay, and the expression of Hsp90protein determined with Western blot. Cell cycledistribution of the transfectants was analyzedwith flow cytometry, and the drug sensitivity ofthe transfectants to adriamycin (ADR ),vincrinstine (VCR ), mitomycin (MMC ) andcyclophosphamide (CTX ) with MTT andintracellular drug concentration of thetransfectants was determined with flowcytometry.RESULTS In EcoR 1 and BamH I restrictionanalysis, the size and the direction of the clonedsequence of Hsp900 remained what had beendesigned and the gene constructs were namedpcDNA-Hsp90. AH^SGC7901, AH^SGC7901/ VCR,AH-HCC7402 and AH-Eel09 cell clones allexpressed Hsp90 anti--sense RNA. Theexpression of Hsp90 was down--regulated in AHSGC7901, AH--SGC7901/ VCR, AH-HCC7402 andAH--Eel09 cell clones. Cell cycle distribution waschanged differently. In AH-SGC7901/ VCR andAH-Ec109 cells, G, phase cells were increased; Sphase and G, phase cells were decreased ascompared with their parental cell lines. In AHSGC7901 cell, G, phase cells were decreased, Qphase cells increased and S phase cells were notchanged, and in AH-HCC7402 cells G,, S and qphase cells remained unchanged as comparedwith their parental cell lines. The sensitivity ofAH--SGC7901, AH--SGC7901/ VCR, AH-HCC7402 andAH-Ec109 to chemotherapeutic drugs, thesensitivity ot AH--SGC7901/ VCR to ADR, VCR,MMC and CTX the sensitivity of AH-HCC7402 toADR and VCR, and the sensitivity of Eel09 toADR, VCR and CTX all increased as comparedwith their parental cell lines. The meanfluorescence intensity of ADR in AH--SGC7901,AH-SGC7901/ VCR, AH--HCC7402 and AH-Ec109was also significantly elevated (P< 0. 05).CONCLUSION Down-regulation of HsP90 couldchange cell cycle distribution and increase thedrug sensitivity of tumor cells.

Osthole inhibits proliferation of human breast cancer cells by inducing cell cycle arrest and apoptosis

Recent studies have revealed that osthole,an active constituent isolated from the fruit of Cnidium monnieri（L.） Cusson,a traditional Chinese medicine,possesses anticancer activity.However,its effect on breast cancer cells so far has not been elucidated clearly.In the present study,we evaluated the effects of osthole on the proliferation,cell cycle and apoptosis of human breast cancer cells MDA-MB 435.We demonstrated that osthole is effective in inhibiting the proliferation of MDA-MB 435 cells,The mitochondrion-mediated apoptotic pathway was involved in apoptosis induced by osthole,as indicated by activation of caspase-9 and caspase-3 followed by PARP degradation.The mechanism underlying its effect on the induction of G1 phase arrest was due to the up-regulation of p53 and p21 and down-regulation of Cdk2 and cyclin D1 expression.Were observed taken together,these findings suggest that the anticancer efficacy of osthole is mediated via induction of cell cycle arrest and apoptosis in human breast cancer cells and osthole may be a potential chemotherapeutic agent against human breast cancer.

Change of the cell cycle after flutamide treatment in prostate cancer cells and its molecular mechanism

Aim： To explore the effect of androgen receptor （AR） on the expression of the cell cycle-related genes, such as CDKNIA and BTG1, in prostate cancer cell line LNCaP. Methods： After AR antagonist flutamide treatment and confirmation of its effect by phase contrast microscope and flow cytometry, the differential expression of the cell cycle-related genes was analyzed by a cDNA microarray. The flutamide treated cells were set as the experimental group and the LNCaP cells as the control. We labeled cDNA probes of the experimental group and control group with Cy5 and Cy3 dyes, respectively, through reverse transcription. Then we hybridized the cDNA probes with cDNA microarrays, which contained 8 126 unique human cDNA sequences and the chip was scanned to get the fluorescent values of Cy5 and Cy3 on each spot. After primary analysis, reverse transcription polymerase chain reaction （RT- PCR） tests were carried out to confirm the results of the chips. Results：After AR antagonist flutamide treatment, three hundred and twenty-six genes （3.93 %） expressed differentially, 97 down-regulated and 219 up-regulated. Among them, eight up-regulated genes might be cell cycle-related, namely CDCIO, NRAS, BTG1, Wee1, CLK3, DKFZP564A122, CDKNIA and BTG2. The CDKNIA and BTG1 gene mRNA expression was confirmed to be higher in the experimental group by RT-PCR, while p53 mRNA expression had no significant changes. Conclusion： Flutamide treatment might up-regulate CDKN1A and BTG1 expression in prostate cancer cells. The protein expressions of CDKN1A and BTG1 play an important role in inhibiting the proliferation of cancer cells. CDKN1A has a great impact on the cell cycle of prostate cancer cells and may play a role in the cancer cells in a p53-independent pathway. The prostate cancer cells might affect the cell cycle-related genes by activating AR and thus break the cell cycle control.

Ent-11α-Hydroxy-15-oxo-kaur-16-en-19-oic-acid Inhibits Growth of Human Lung Cancer A549 Cells by Arresting Cell Cycle and Triggering Apoptosis

Objective： To examine the apoptotic effect of ent-llα-hydroxy-15-oxo-kaur-16-en-19-oic-acid （5F）, a compound isolated from Pteris semipinnata L （PsL）, in human lung cancer A549 cells. Methods： A549 cells were treated with 5F （0-80 lag/ml） for different time periods. Cytotoxicity was examined using a Ml-I- method. Cell cycle was examined using propidium iodide staining. Apoptosis was examined using Hoechst 33258 staining, enzyme-linked immunosorbent assay （ELISA） and caspase-3 activity analysis. Expression of representative apoptosis-related proteins was evaluated by Western blot analysis. Reactive oxygen species （ROS） level was measured using standard protocols. Potential interaction of 5F with cisplatin was also examined. Results： 5F inhibited the proliferation of A549 cells in a concentration- and time-dependent manner. 5F increased the accumulation of cells in sub-G1 phase and arrested the cells in the G2 phase. Exposure to 5F induced morphological changes and DNA fragmentation that are characteristic of apoptosis. The expression of p21 was increased. 5F exposure also increased Bax expression, release of cytochrome c and apoptosis inducing factor （AIF）, and activation of caspase-3. 5F significantly sensitized the cells to cisplatin toxicity. Interestingly, treatment with 5F did not increase ROS, but reduced ROS production induced by cisplatin. Conclusion： 5F could inhibit the proliferation of A549 cells by arresting the cells in G2 phase and by inducing mitochondrial-mediated apoptosis.

Effects of Rapamycin on Expression of Bcl-2 and Bax in Human Lens Epithelial Cells and Cell Cycle in Rats

The effects of rapamycin on the expression of Bcl-2 and Bax protein in in vitro cultured human lens epithelial cells（LECs） and cell cycle were investigated in order to provide the theoretical basis for the development of new inhibitory drugs for clinical prevention and treatment of after-cataract.The cultured LECs of second and third passages were collected and treated with rapamycin.The LECs were transferred into 96-well culture plates and divided into 6 groups,and each group was set to have 8 duplicate wells.In the negative control group,the LECs were given culture medium only,and in the blank control group,only culture medium was given.In the four rapamycin-treated groups,different concentrations（20,40,60 and 80 ng/mL） of rapamycin were given.After treatment for 24,48 and 72 h,the absorbance（A） values in each well were determined by MTT assay.The cell cycles of all groups were detected by using flow cytometry.Real-time fluorescent quantitative polymerase chain reaction（RFQ-PCR） and Western blot were used to detect the mRNA and protein expression of Bcl-2 and Bax respectively.MTT assay showed that rapamycin could inhibit proliferation of LECs in a time-and dose-dependent manner.Flow cytometry revealed that rapamycin could block the conversion of LECs from G1 phase to S phase,resulting in the increase of cells in G1 phase and the decrease of the cells in S phase.RFQ-PCR indicated that rapamycin could down-regulate the expression of Bcl-2 mRNA,but up-regulate the expression of Bax mRNA,suggesting it could induce apoptosis of LECs.Western blot demonstrated that rapamycin could suppress the expression of Bcl-2 protein,but promote the expression of Bax protein.It is concluded that rapamycin could inhibit proliferation of LECs probably not only by blocking the progression of cell cycle,but also by promoting the induction of apoptosis.

Pterocarine, a New Diarylheptanoid from Pterocarya tonkinesis, its Cell Cycle Inhibition at G_0/G_1 Phase and Induction of Apoptosis in HCT-15 and K562 Cells

Pterocarine (1), a new diarylheptanoidal compound, was isolated from Pterocaryatonkinesis (Franch.) Dode. together with a known diarylheptanoid, myricatomentogenin (2), througha bioassay-guided fractionation procedure. The structure of 1 was elucidated as (+)-3', 4''-epoxy-1-(4'-hydroxyphenyl)-7-(3''-hydroxyphenyl)-heptane-3-one by the spectroscopic methods.Pterocarine (1) inhibited the proliferation of tsFT210, HCT-15 and K562 cells with the inhibitionrates of 20.2±2.4, 23.8±2.4 and 50.5±1.2% at 100 μg/mL, respectively. Flow cytometric analysisindicated that 1 could inhibit the cell cycle of tsFT210, HCT-15 and K562 cells at the G0/G1 phaseand could also induce apoptosis in HCT-15 (19%) and K562 (11%) cells.

Paris Saponin Ⅰ Induces G_2/M Cell Cycle Arrest and Apoptosis in Human Gastric Carcinoma SGC7901 Cells

The aim of this study was to investigate the effect of Paris saponin I （PSI ） on human gastric carcinoma cell growth and apoptosis and to explore the potential mechanisms. The proliferation of SGC7901 cells was monitored by the MTT cell viability assay, while the nuclear morphology of apoptotic cells was assessed by Hoechst 33258 staining. Flow cytometry was performed to analyze the cell cycle progression of propidium iodide （PI）-stained SGC7901 cells and the apoptotic rate of annexin V/PI-stained ceils. Western blotting was used to examine the expression of several cell cycle proteins, including cyclin 131 and Cdkl, and the apoptosis-regulated proteins Bcl-2, Bax, cytochrome c, procaspase-9, and procaspase-3. The MTT assay demonstrated that PSI could induce significant dose- and time-dependent inhibition of SGC7901 cell proliferation. Marked morphological changes, including condensation of chromatin, nuclear fragmentation and apoptotic bodies were clearly shown on Hoechst 33258 staining. PS I treatment also resulted in the disruption of the cell cycle at Gz/M and the induction of apoptosis. Following PSI treatment, the cell cycle-related proteins cyclin B 1 and Cdkl were down- regulated. Expression of the pro-apoptotic protein Bax was increased, while anti-apoptotic protein Bcl-2 decreased. PSI treatment resulted in elevated cytoplasmic cytochrome c and activation of the apoptotic proteases caspase-9 and caspase-3. These data indicate that PS I acts as an inhibitor of proliferation in SGC7901 cells by inducing cell cycle arrest and mitochondria-dependent apoptosis. PSI is a potential therapeutic agent against human gastric carcinoma.

Downregulation of SNRPG induces cell cycle arrest and sensitizes human glioblastoma cells to temozolomide by targeting Myc through a p53-dependent signaling pathway

Objective:Temozolomide(TMZ)is commonly used for glioblastoma multiforme(GBM)chemotherapy.However,drug resistance limits its therapeutic effect in GBM treatment.RNA-binding proteins(RBPs)have vital roles in posttranscriptional events.While disturbance of RBP-RNA network activity is potentially associated with cancer development,the precise mechanisms are not fully known.The SNRPG gene,encoding small nuclear ribonucleoprotein polypeptide G,was recently found to be related to cancer incidence,but its exact function has yet to be elucidated.Methods:SNRPG knockdown was achieved via short hairpin RNAs.Gene expression profiling and Western blot analyses were used to identify potential glioma cell growth signaling pathways affected by SNRPG.Xenograft tumors were examined to determine the carcinogenic effects of SNRPG on glioma tissues.Results:The SNRPG-mediated inhibitory effect on glioma cells might be due to the targeted prevention of Myc and p53.In addition,the effects of SNRPG loss on p53 levels and cell cycle progression were found to be Myc-dependent.Furthermore,SNRPG was increased in TMZ-resistant GBM cells,and downregulation of SNRPG potentially sensitized resistant cells to TMZ,suggesting that SNRPG deficiency decreases the chemoresistance of GBM cells to TMZ via the p53 signaling pathway.Our data confirmed that SNRPG suppression sensitizes GBM cells to TMZ by targeting Myc via the p53 signaling cascade.Conclusions:These results indicated that SNRPG is a probable molecular target of GBM and suggested that suppressing SNRPG in resistant GBM cells might be a substantially beneficial method for overcoming essential drug resistance.

Arsenic Trioxide Inhibits Proliferation in K562 Cells by Changing Cell Cycle and Survivin Expression

To study the mechanisms involved in the inhibition of chronic myeloid leukemic cells (K562) proliferation induced by arsenic trioxide (As 2O 3) and to explore the potential role of Survivin, an inhibitor of apoptosis protein, in the regulation of As 2O 3 induced cell apoptosis, K562 cells were cultured with As 2O 3 of different concentrations. Cells were collected for proliferation analysis by MTT assay. Cell cycle distribution and cell apoptosis were analyzed by flow cytometry. Expression of Survivin protein and mRNA were detected by flow cytometry and RT-PCR, respectively. Our results showed that As 2O 3 (2-10 μmol/L) inhibited K562 cells growth effectively, but it did not induce cells apoptosis significantly. The percentage of K562 cells at G 2/M phase increased in proportion to As 2O 3 concentrations, and the expression of Survivin mRNA and content of Survivin protein was up-regulated accordingly. It is concluded that As 2O 3 inhibited K562 cells growth by inducing cell cycle arrest mainly at G 2/M phase. Over-expression of Survivin gene and protein might be one of the possible mechanisms contributing to K562 cells' resistance to As 2O 3-induced apoptosis.

Artesunate Reduces Proliferation, Interferes DNA Replication and Cell Cycle and Enhances Apoptosis in Vascular Smooth Muscle Cells

Summary: This study examined the effect of artesunate (Art) on the proliferation, DNA replication, cell cycles and apoptosis of vascular smooth muscle cells (VSMCs). Primary cultures of VSMCs were established from aortas of mice and artesunate of different concentrations was added into the medium. The number of VSMCs was counted and the curve of cell growth was recorded. The activity of VSMCs was assessed by using MTT method and inhibitory rate was calculated. DNA replication was evaluated by [3H]-TdR method and apoptosis by DNA laddering and HE staining. Flowmetry was used for simultaneous analysis of cell apoptosis and cell cycles. Compared with the control group, VSMCs proliferation in Art interfering groups were inhibited and [3H]-TdR incorprating rate were decreased as well as cell apoptosis was induced. The progress of cell cycle was blocked in G 0/G 1 by Art in a dose-dependent manner. It is concluded that Art inhibits VSMCs proliferation by disturbing DNA replication, inducing cell apoptosis and blocking cell cycle in G 0/G 1 phase.

Effect of Lithium on Cell Cycle Progression of Pig Airway Epithelial Cells

To investigate the effect of lithium on cell cycle progression of airway epithelial cells, primary pig tracheobronchial epithelial cells were incubated with lithium chloride (LiCl) at different concentrations (0, 5 mmol/L, and 10 mmol/L) and time (12 h, 16 h and 24 h). After the treatment, cells were counted, cell cycle profile was measured by BrdU labeling and flow cytometry, and expression of cyclin D1 and cyclin B1 were detected by Western blotting. The results showed that after 24h of 10mmol/L but not 5mmol/L LiCl treatment, proliferation of cells was slowed down as manifested by delayed confluence and cell number accumulation (P<0.05). Lithium did not change the percentage of cells in S phase (P>0.05), but 24 h incubation with 10 mmol/L LiCl induced a G 2/M cell cycle arrest. Furthermore, 10mmol/L LiCl elevated cyclin D1 expression after 12h treatment, while expression of cyclin B1 increased more significantly after 24h incubation. These data demonstrate that lithium inhibits proliferation of pig airway epithelial cells by inhibiting cell cycle progression, and suggest that lithium-sensitive molecule(s) such as glycogen synthase kinase 3 may have a role in the regulation of growth of airway epithelial cells.