BACKGROUND Colorectal cancer(CRC)is the third most common cancer and a significant cause of cancer-related mortality globally.Resistance to chemotherapy,especially during CRC treatment,leads to reduced effectiveness o...BACKGROUND Colorectal cancer(CRC)is the third most common cancer and a significant cause of cancer-related mortality globally.Resistance to chemotherapy,especially during CRC treatment,leads to reduced effectiveness of drugs and poor patient outcomes.Long noncoding RNAs(lncRNAs)have been implicated in various pathophysiological processes of tumor cells,including chemotherapy resistance,yet the roles of many lncRNAs in CRC remain unclear.AIM To identify and analyze the lncRNAs involved in oxaliplatin resistance in CRC and to understand the underlying molecular mechanisms influencing this resistance.METHODS Gene Expression Omnibus datasets GSE42387 and GSE30011 were reanalyzed to identify lncRNAs and mRNAs associated with oxaliplatin resistance.Various bioinformatics tools were employed to elucidate molecular mechanisms.The expression levels of lncRNAs and mRNAs were assessed via quantitative reverse transcription-polymerase chain reaction.Functional assays,including MTT,wound healing,and Transwell,were conducted to investigate the functional implications of lncRNA alterations.Interactions between lncRNAs and trans-cription factors were examined using RIP and luciferase reporter assays,while Western blotting was used to confirm downstream pathways.Additionally,a xenograft mouse model was utilized to study the in vivo effects of lncRNAs on chemotherapy resistance.RESULTS LncRNA prion protein testis specific(PRNT)was found to be upregulated in oxaliplatin-resistant CRC cell lines and negatively correlated with homeodomain interacting protein kinase 2(HIPK2)expression.PRNT was demonstrated to sponge transcription factor zinc finger protein 184(ZNF184),which in turn could regulate HIPK2 expression.Altered expression of PRNT influenced CRC cell sensitivity to oxaliplatin,with overexpression leading to decreased sensitivity and decreased expression reducing resistance.Both RIP and luciferase reporter assays indicated that ZNF184 and HIPK2 are targets of PRNT.The PRNT/ZNF184/HIPK2 axis was implicated in promoting CRC progression and oxaliplatin resistance both in vitro and in vivo.CONCLUSION The study concludes that PRNT is upregulated in oxaliplatin-resistant CRC cells and modulates the expression of HIPK2 by sponging ZNF184.This regulatory mechanism enhances CRC progression and resistance to oxaliplatin,positioning PRNT as a promising therapeutic target for CRC patients undergoing oxaliplatin-based chemotherapy.展开更多
BACKGROUND Trastuzumab constitutes the fundamental component of initial therapy for patients with advanced human epidermal growth factor receptor 2(HER-2)-positive gastric cancer(GC).However,the efficacy of this treat...BACKGROUND Trastuzumab constitutes the fundamental component of initial therapy for patients with advanced human epidermal growth factor receptor 2(HER-2)-positive gastric cancer(GC).However,the efficacy of this treatment is hindered by substantial challenges associated with both primary and acquired drug resistance.While S-phase kinase associated protein 2(Skp2)overexpression has been implicated in the malignant progression of GC,its role in regulating trastuzumab resistance in this context remains uncertain.Despite the numerous studies investigating Skp2 inhibitors among small molecule compounds and natural products,there has been a lack of successful commercialization of drugs specifically targeting Skp2.AIM To discover a Skp2 blocker among currently available medications and develop a therapeutic strategy for HER2-positive GC patients who have experienced progression following trastuzumab-based treatment.METHODS Skp2 exogenous overexpression plasmids and small interfering RNA vectors were utilized to investigate the correlation between Skp2 expression and trastuzumab resistance in GC cells.Q-PCR,western blot,and immunohistochemical analyses were conducted to evaluate the regulatory effect of thioridazine on Skp2 expression.A cell counting kit-8 assay,flow cytometry,a amplex red glucose/glucose oxidase assay kit,and a lactate assay kit were utilized to measure the proliferation,apoptosis,and glycolytic activity of GC cells in vitro.A xenograft model established with human GC in nude mice was used to assess thioridazine's effectiveness in vivo.RESULTS The expression of Skp2 exhibited a negative correlation with the sensitivity of HER2-positive GC cells to trastuzumab.Thioridazine demonstrated the ability to directly bind to Skp2,resulting in a reduction in Skp2 expression at both the transcriptional and translational levels.Moreover,thioridazine effectively inhibited cell proliferation,exhibited antiapoptotic properties,and decreased the glucose uptake rate and lactate production by suppressing Skp2/protein kinase B/mammalian target of rapamycin/glucose transporter type 1 signaling pathways.The combination of thioridazine with either trastuzumab or lapatinib exhibited a more pronounced anticancer effect in vivo,surpassing the efficacy of either monotherapy.CONCLUSION Thioridazine demonstrates promising outcomes in preclinical GC models and offers a novel therapeutic approach for addressing trastuzumab resistance,particularly when used in conjunction with lapatinib.This compound has potential benefits for patients with Skp2-proficient tumors.展开更多
Populus tomentosa seedlings used for cold acclimation at -3℃ were pretreated with or without 10?mmol·L -1 CaCl 2, 3?mmol·L -1 of Ca 2+ chelator EGTA, 0 1?mmol·L -1 of Ca 2+ ...Populus tomentosa seedlings used for cold acclimation at -3℃ were pretreated with or without 10?mmol·L -1 CaCl 2, 3?mmol·L -1 of Ca 2+ chelator EGTA, 0 1?mmol·L -1 of Ca 2+ channel inhibitor LaCl 3,and 0 05?mmol·L -1 of CaM antagonist CPZ. The changes in the contents of total soluble protein and CaM, and freezing resistance in all pretreated seedlings in various periods ( viz: following cold acclimation, chilling stress and recovery) were investigated. Results showed that cold acclimation increased the contents of total soluble protein and CaM, and freezing resistance of seedlings, which could be strongly reduced by the pretreatments of EGTA CPZ and LaCl 3 Cold acclimation combined with CaCl 2 pretreatment enhanced the effect of cold acclimation on freezing resistance, and obviously increased the contents of total soluble protein and CaM, reduced the declining degree of the contents of total soluble protein and CaM caused by chilling stress as compared with cold acclimation, augmented the increase in the level of total soluble protein and CaM during the recovery periods. Further analysis found that an increase in total soluble protein content during cold acclimation with or without CaCl 2 pretreatment mainly resulted from the increase in content of heat stable protein in total soluble protein. It is suggested that Ca 2+ calmodulin may be involved in the synthesis of total soluble protein, and the induction of freezing resistance of seedlings.展开更多
BACKGROUND:Multidrug resistance(MDR)is extremely common in hepatocellular carcinoma(HCC)and is a major problem in cancer eradication by limiting the efficacy of chemotherapy.Modulation of c-Jun NH2-terminal kinase(JNK...BACKGROUND:Multidrug resistance(MDR)is extremely common in hepatocellular carcinoma(HCC)and is a major problem in cancer eradication by limiting the efficacy of chemotherapy.Modulation of c-Jun NH2-terminal kinase(JNK)activation could be a new method to reverse MDR.However,the relationship between JNK activity and MDR in HCC cells is unknown.This study aimed to explore the relationship between MDR and JNK in HCC cell lines with different degrees of MDR.METHODS:A MDR human HCC cell line,SMMC-7721/ ADM,was developed by exposing parental cells to gradually increasing concentrations of adriamycin.The MTT assay was used to determine drug sensitivity.Flow cytometry was used to analyze the cell cycle distribution and to measure the expression levels of P-glycoprotein(P-gp)and MDR-related protein(MRP)-1 in these cells.JNK1,JNK2 and JNK3 mRNA expression levels were quantified by real-time PCR.Expression and phosphorylation of JNK1,JNK2,and JNK3 were analyzed by Western blotting.RESULTS:The MDR of SMMC-7721/ADM cells resistant to 0.05 mg/L adriamycin was mainly attributed to the overexpression of P-gp but not MRP1.In addition,these cells had a significant increase in percentage in the S phase,accompanied by a decrease in percentage in the G0/G1 phase,which is likely associated with a reduced ability for cell proliferation and MDR generation.We found that JNK1,JNK2,and JNK3 activities were negatively correlated with the degree of MDR in HCC cells.CONCLUSION:This study suggests that JNK1,JNK2,and JNK3 activities are negatively correlated with the degree of MDR in HCC cells.展开更多
Objective： To study the relationship between the methylation status of multi-drug resistance protein （MRP） gene and the expression of its mRNA and protein in lung cancer cell lines. Methods： Human embryo lung cell...Objective： To study the relationship between the methylation status of multi-drug resistance protein （MRP） gene and the expression of its mRNA and protein in lung cancer cell lines. Methods： Human embryo lung cell line WI-38, lung adenocarcinoma cell line SPCA-1 and its drug-resistant cells induced by different concentrations of doxorubicin were treated with restriction endonuclease Eco47III. The methylation status of MRP was examined by PCR, and the expressions of its mRNA and protein were evaluated by in situ hybridization and immunohistochemistry. Results： MRP gene promoter region of WI-38 cells was in hypermethylation status, but the promoter region of MRP in SPCA-1 cells and their resistant derivatives induced by different concentrations of doxorubicin were in hypomethylation status. There were significant differences in the expression of MRP mRNA among WI-38 cell line, SPCA-1 cells and their drug-resistant derivatives induced by different concentration of doxorubicin. Consistently, MRP immunostaining presented similar significant differences. Conclusion： The promoter region of MRP in SPCA-1 lung adenocarcinoma cells was in hypomethylation status. The hypomethylation status of 5＇ regulatory region of MRP promoter is an important structural basis that can increase the activity of transcription and results in the development of drug resistance in lung cancer.展开更多
Free fatty acids are known to play a key role in promoting loss of insulin sensitivity in type 2 diabetes mellitus but the underlying mechanism is still unclear.It has been postulated that an increase in the intracell...Free fatty acids are known to play a key role in promoting loss of insulin sensitivity in type 2 diabetes mellitus but the underlying mechanism is still unclear.It has been postulated that an increase in the intracellular concentration of fatty acid metabolites activates a serine kinase cascade,which leads to defects in insu-lin signaling downstream to the insulin receptor.In addition,the complex network of adipokines released from adipose tissue modulates the response of tissues to insulin.Among the many molecules involved in the intracellular processing of the signal provided by insulin,the insulin receptor substrate-2,the protein kinase B and the forkhead transcription factor Foxo 1a are of particular interest,as recent data has provided strong evidence that dysfunction of these proteins results in insulin resistance in vivo.Recently,studies have revealed that phosphoinositidedependent kinase 1-independent phosphorylation of protein kinase Cε causes a reduction in insulin receptor gene expression.Additionally,it has been suggested that mitochondrial dysfunction triggers activation of several serine kinases,and weakens insulin signal transduction.Thus,in this review,the current developments in understanding the pathophysiological processes of insulin resistance in type 2 diabetes have been summarized.In addition,this study provides potential new targets for the treatment and prevention of type 2 diabetes.展开更多
AIM:To clarify the specific roles and mechanisms of long interspersed nuclear element-1 ORF-1 protein [human long interspersed nuclear element-1(LINE-1),ORF-1p] in chemotherapeutic drug resistance and cell proliferati...AIM:To clarify the specific roles and mechanisms of long interspersed nuclear element-1 ORF-1 protein [human long interspersed nuclear element-1(LINE-1),ORF-1p] in chemotherapeutic drug resistance and cell proliferation regulation in hepatocellular carcinoma(HCC) cells.METHODS:MTT assays were performed to identify the effect of the chemotherapeutic drug toxicity on HepG2 cells.Cell proliferation inhibition and the IC 50 were calculated by the Origin 8.0 software.Western blotting assays were performed to investigate whether LINE-1 ORF-1p modulates the expression of some important genes,including p53,p27,p15,Bcl-2,mdr,and p-gp.To corroborate the proliferation and anchor-independent growth results,the HepG2 cells were analyzed by flow cytometry to investigate the effect of LINE-1 ORF1p on the apoptosis regulation.RESULTS:LINE-1 ORF-1p contributed to the resistance to several chemotherapeutic drugs(cisplatin and epirubicin) in HepG2 cells.The IC 50 of the epirubicin and cisplatin increased from 36.04 nmol/L to 59.11 nmol/L or from 37.94 nmol/L to 119.32 nmol/L.Repression of LINE-1 ORF-1p expression by the siRNA could markedly enhance the response of HepG2 cells to the epirubicin and cisplatin.The IC 50 correspondingly decreased from 28.06 nmol/L to 3.83 nmol/L or from 32.04 nmol/L to 2.89 nmol/L.Interestingly,down-regulation of LINE-1 ORF-1p level by siRNA could promote the response of HepG2 cells to the paclitaxel.The IC 50 decreased from 35.90 nmol/L to 7.36 nmol/L.However,overexpression of LINE-1 ORF-1p did not modulate the paclitaxel toxicity in HepG2 cells.Further Western blotting revealed that LINE-1 ORF-1p enhanced mdr and p-gp gene expression.As a protein arrested in the nucleus,LINE-1 ORF-1p may function through modulating transcriptional activity of some important transcription factors.Indeed,LINE-1 ORF-1p promoted HepG2 cell proliferation,anchor-independent growth and protected the cells against apoptosis through modulating the expression of p15,p21,p53,and Bcl-2 genes.CONCLUSION:LINE-1 ORF-1p promotes HepG2 cell proliferation and plays an important role in the resistance of chemotherapeutic drugs.By establishing novel roles and defining the mechanisms of LINE-1 ORF1p in HCC chemotherapeutic drug resistance and cell proliferation regulation,this study indicates that LINE-1 ORF-1p is a potential target for overcoming HCC chemotherapeutic resistance.展开更多
PM2 gene （accession number： M80664） with high lysine content from soybean （Glycine max） was found in GenBank by changing three BLASTp parameters. Amino acid composition analysis of PM2 showed that Lys content was...PM2 gene （accession number： M80664） with high lysine content from soybean （Glycine max） was found in GenBank by changing three BLASTp parameters. Amino acid composition analysis of PM2 showed that Lys content was on the high level of 18.22%. Protein encoded by PM＇2 also belonged to the family of late embryogenesis abundant （LEA） proteins, which was considered that it had a strong relation with the abiotic stress resistance. In this experiment, PM2 gene was obtained from dry soybean seeds by RT-PCR, plant expression vector pEMTPM2 was constructed, and then transformed into tobacco by using agrobacterium-mediated method. Eight salt and drought tolerant lines were obtained from 31 differentiated lines. Real-time PCR showed that PM2 gene overexpressed in all four PCR positive lines with the osmotic stress resistance. These results confirmed that the overexpression of PM2 gene enhanced the osmotic stress resistance of transgenic tobacco.展开更多
基金Supported by Hebei Provincial Health Commission Youth Science and Technology Project,No.20210027.
文摘BACKGROUND Colorectal cancer(CRC)is the third most common cancer and a significant cause of cancer-related mortality globally.Resistance to chemotherapy,especially during CRC treatment,leads to reduced effectiveness of drugs and poor patient outcomes.Long noncoding RNAs(lncRNAs)have been implicated in various pathophysiological processes of tumor cells,including chemotherapy resistance,yet the roles of many lncRNAs in CRC remain unclear.AIM To identify and analyze the lncRNAs involved in oxaliplatin resistance in CRC and to understand the underlying molecular mechanisms influencing this resistance.METHODS Gene Expression Omnibus datasets GSE42387 and GSE30011 were reanalyzed to identify lncRNAs and mRNAs associated with oxaliplatin resistance.Various bioinformatics tools were employed to elucidate molecular mechanisms.The expression levels of lncRNAs and mRNAs were assessed via quantitative reverse transcription-polymerase chain reaction.Functional assays,including MTT,wound healing,and Transwell,were conducted to investigate the functional implications of lncRNA alterations.Interactions between lncRNAs and trans-cription factors were examined using RIP and luciferase reporter assays,while Western blotting was used to confirm downstream pathways.Additionally,a xenograft mouse model was utilized to study the in vivo effects of lncRNAs on chemotherapy resistance.RESULTS LncRNA prion protein testis specific(PRNT)was found to be upregulated in oxaliplatin-resistant CRC cell lines and negatively correlated with homeodomain interacting protein kinase 2(HIPK2)expression.PRNT was demonstrated to sponge transcription factor zinc finger protein 184(ZNF184),which in turn could regulate HIPK2 expression.Altered expression of PRNT influenced CRC cell sensitivity to oxaliplatin,with overexpression leading to decreased sensitivity and decreased expression reducing resistance.Both RIP and luciferase reporter assays indicated that ZNF184 and HIPK2 are targets of PRNT.The PRNT/ZNF184/HIPK2 axis was implicated in promoting CRC progression and oxaliplatin resistance both in vitro and in vivo.CONCLUSION The study concludes that PRNT is upregulated in oxaliplatin-resistant CRC cells and modulates the expression of HIPK2 by sponging ZNF184.This regulatory mechanism enhances CRC progression and resistance to oxaliplatin,positioning PRNT as a promising therapeutic target for CRC patients undergoing oxaliplatin-based chemotherapy.
基金Supported by Youth Fund of National Natural Science Foundation of China,No.81803575,No.31902287Kaifeng Science and Technology Development Plan Project,No.2203008+2 种基金Key Specialized Research and Promotion Project of Henan Province in 2023,No.232102311205Henan Medical Science and Technology Research Program Project,No.LHGJ20210801College Students Innovation and Entrepreneurship Training Program of Henan University,No.20231022007.
文摘BACKGROUND Trastuzumab constitutes the fundamental component of initial therapy for patients with advanced human epidermal growth factor receptor 2(HER-2)-positive gastric cancer(GC).However,the efficacy of this treatment is hindered by substantial challenges associated with both primary and acquired drug resistance.While S-phase kinase associated protein 2(Skp2)overexpression has been implicated in the malignant progression of GC,its role in regulating trastuzumab resistance in this context remains uncertain.Despite the numerous studies investigating Skp2 inhibitors among small molecule compounds and natural products,there has been a lack of successful commercialization of drugs specifically targeting Skp2.AIM To discover a Skp2 blocker among currently available medications and develop a therapeutic strategy for HER2-positive GC patients who have experienced progression following trastuzumab-based treatment.METHODS Skp2 exogenous overexpression plasmids and small interfering RNA vectors were utilized to investigate the correlation between Skp2 expression and trastuzumab resistance in GC cells.Q-PCR,western blot,and immunohistochemical analyses were conducted to evaluate the regulatory effect of thioridazine on Skp2 expression.A cell counting kit-8 assay,flow cytometry,a amplex red glucose/glucose oxidase assay kit,and a lactate assay kit were utilized to measure the proliferation,apoptosis,and glycolytic activity of GC cells in vitro.A xenograft model established with human GC in nude mice was used to assess thioridazine's effectiveness in vivo.RESULTS The expression of Skp2 exhibited a negative correlation with the sensitivity of HER2-positive GC cells to trastuzumab.Thioridazine demonstrated the ability to directly bind to Skp2,resulting in a reduction in Skp2 expression at both the transcriptional and translational levels.Moreover,thioridazine effectively inhibited cell proliferation,exhibited antiapoptotic properties,and decreased the glucose uptake rate and lactate production by suppressing Skp2/protein kinase B/mammalian target of rapamycin/glucose transporter type 1 signaling pathways.The combination of thioridazine with either trastuzumab or lapatinib exhibited a more pronounced anticancer effect in vivo,surpassing the efficacy of either monotherapy.CONCLUSION Thioridazine demonstrates promising outcomes in preclinical GC models and offers a novel therapeutic approach for addressing trastuzumab resistance,particularly when used in conjunction with lapatinib.This compound has potential benefits for patients with Skp2-proficient tumors.
文摘Populus tomentosa seedlings used for cold acclimation at -3℃ were pretreated with or without 10?mmol·L -1 CaCl 2, 3?mmol·L -1 of Ca 2+ chelator EGTA, 0 1?mmol·L -1 of Ca 2+ channel inhibitor LaCl 3,and 0 05?mmol·L -1 of CaM antagonist CPZ. The changes in the contents of total soluble protein and CaM, and freezing resistance in all pretreated seedlings in various periods ( viz: following cold acclimation, chilling stress and recovery) were investigated. Results showed that cold acclimation increased the contents of total soluble protein and CaM, and freezing resistance of seedlings, which could be strongly reduced by the pretreatments of EGTA CPZ and LaCl 3 Cold acclimation combined with CaCl 2 pretreatment enhanced the effect of cold acclimation on freezing resistance, and obviously increased the contents of total soluble protein and CaM, reduced the declining degree of the contents of total soluble protein and CaM caused by chilling stress as compared with cold acclimation, augmented the increase in the level of total soluble protein and CaM during the recovery periods. Further analysis found that an increase in total soluble protein content during cold acclimation with or without CaCl 2 pretreatment mainly resulted from the increase in content of heat stable protein in total soluble protein. It is suggested that Ca 2+ calmodulin may be involved in the synthesis of total soluble protein, and the induction of freezing resistance of seedlings.
基金supported by grants from the Medical Innovation Fundation of Fujian Province(No.2007-CXB-7)the Natural Science Foundation of Fujian Province(No.2009D010)
文摘BACKGROUND:Multidrug resistance(MDR)is extremely common in hepatocellular carcinoma(HCC)and is a major problem in cancer eradication by limiting the efficacy of chemotherapy.Modulation of c-Jun NH2-terminal kinase(JNK)activation could be a new method to reverse MDR.However,the relationship between JNK activity and MDR in HCC cells is unknown.This study aimed to explore the relationship between MDR and JNK in HCC cell lines with different degrees of MDR.METHODS:A MDR human HCC cell line,SMMC-7721/ ADM,was developed by exposing parental cells to gradually increasing concentrations of adriamycin.The MTT assay was used to determine drug sensitivity.Flow cytometry was used to analyze the cell cycle distribution and to measure the expression levels of P-glycoprotein(P-gp)and MDR-related protein(MRP)-1 in these cells.JNK1,JNK2 and JNK3 mRNA expression levels were quantified by real-time PCR.Expression and phosphorylation of JNK1,JNK2,and JNK3 were analyzed by Western blotting.RESULTS:The MDR of SMMC-7721/ADM cells resistant to 0.05 mg/L adriamycin was mainly attributed to the overexpression of P-gp but not MRP1.In addition,these cells had a significant increase in percentage in the S phase,accompanied by a decrease in percentage in the G0/G1 phase,which is likely associated with a reduced ability for cell proliferation and MDR generation.We found that JNK1,JNK2,and JNK3 activities were negatively correlated with the degree of MDR in HCC cells.CONCLUSION:This study suggests that JNK1,JNK2,and JNK3 activities are negatively correlated with the degree of MDR in HCC cells.
基金This work was supported by grants from Shanghai Educational Committee Funds(No.99B18).
文摘Objective： To study the relationship between the methylation status of multi-drug resistance protein （MRP） gene and the expression of its mRNA and protein in lung cancer cell lines. Methods： Human embryo lung cell line WI-38, lung adenocarcinoma cell line SPCA-1 and its drug-resistant cells induced by different concentrations of doxorubicin were treated with restriction endonuclease Eco47III. The methylation status of MRP was examined by PCR, and the expressions of its mRNA and protein were evaluated by in situ hybridization and immunohistochemistry. Results： MRP gene promoter region of WI-38 cells was in hypermethylation status, but the promoter region of MRP in SPCA-1 cells and their resistant derivatives induced by different concentrations of doxorubicin were in hypomethylation status. There were significant differences in the expression of MRP mRNA among WI-38 cell line, SPCA-1 cells and their drug-resistant derivatives induced by different concentration of doxorubicin. Consistently, MRP immunostaining presented similar significant differences. Conclusion： The promoter region of MRP in SPCA-1 lung adenocarcinoma cells was in hypomethylation status. The hypomethylation status of 5＇ regulatory region of MRP promoter is an important structural basis that can increase the activity of transcription and results in the development of drug resistance in lung cancer.
文摘Free fatty acids are known to play a key role in promoting loss of insulin sensitivity in type 2 diabetes mellitus but the underlying mechanism is still unclear.It has been postulated that an increase in the intracellular concentration of fatty acid metabolites activates a serine kinase cascade,which leads to defects in insu-lin signaling downstream to the insulin receptor.In addition,the complex network of adipokines released from adipose tissue modulates the response of tissues to insulin.Among the many molecules involved in the intracellular processing of the signal provided by insulin,the insulin receptor substrate-2,the protein kinase B and the forkhead transcription factor Foxo 1a are of particular interest,as recent data has provided strong evidence that dysfunction of these proteins results in insulin resistance in vivo.Recently,studies have revealed that phosphoinositidedependent kinase 1-independent phosphorylation of protein kinase Cε causes a reduction in insulin receptor gene expression.Additionally,it has been suggested that mitochondrial dysfunction triggers activation of several serine kinases,and weakens insulin signal transduction.Thus,in this review,the current developments in understanding the pathophysiological processes of insulin resistance in type 2 diabetes have been summarized.In addition,this study provides potential new targets for the treatment and prevention of type 2 diabetes.
基金Supported by The Key Scientific and Technological Research Foundation of the National Special Purpose Program,No.2008ZX10002-018
文摘AIM:To clarify the specific roles and mechanisms of long interspersed nuclear element-1 ORF-1 protein [human long interspersed nuclear element-1(LINE-1),ORF-1p] in chemotherapeutic drug resistance and cell proliferation regulation in hepatocellular carcinoma(HCC) cells.METHODS:MTT assays were performed to identify the effect of the chemotherapeutic drug toxicity on HepG2 cells.Cell proliferation inhibition and the IC 50 were calculated by the Origin 8.0 software.Western blotting assays were performed to investigate whether LINE-1 ORF-1p modulates the expression of some important genes,including p53,p27,p15,Bcl-2,mdr,and p-gp.To corroborate the proliferation and anchor-independent growth results,the HepG2 cells were analyzed by flow cytometry to investigate the effect of LINE-1 ORF1p on the apoptosis regulation.RESULTS:LINE-1 ORF-1p contributed to the resistance to several chemotherapeutic drugs(cisplatin and epirubicin) in HepG2 cells.The IC 50 of the epirubicin and cisplatin increased from 36.04 nmol/L to 59.11 nmol/L or from 37.94 nmol/L to 119.32 nmol/L.Repression of LINE-1 ORF-1p expression by the siRNA could markedly enhance the response of HepG2 cells to the epirubicin and cisplatin.The IC 50 correspondingly decreased from 28.06 nmol/L to 3.83 nmol/L or from 32.04 nmol/L to 2.89 nmol/L.Interestingly,down-regulation of LINE-1 ORF-1p level by siRNA could promote the response of HepG2 cells to the paclitaxel.The IC 50 decreased from 35.90 nmol/L to 7.36 nmol/L.However,overexpression of LINE-1 ORF-1p did not modulate the paclitaxel toxicity in HepG2 cells.Further Western blotting revealed that LINE-1 ORF-1p enhanced mdr and p-gp gene expression.As a protein arrested in the nucleus,LINE-1 ORF-1p may function through modulating transcriptional activity of some important transcription factors.Indeed,LINE-1 ORF-1p promoted HepG2 cell proliferation,anchor-independent growth and protected the cells against apoptosis through modulating the expression of p15,p21,p53,and Bcl-2 genes.CONCLUSION:LINE-1 ORF-1p promotes HepG2 cell proliferation and plays an important role in the resistance of chemotherapeutic drugs.By establishing novel roles and defining the mechanisms of LINE-1 ORF1p in HCC chemotherapeutic drug resistance and cell proliferation regulation,this study indicates that LINE-1 ORF-1p is a potential target for overcoming HCC chemotherapeutic resistance.
基金Supported by Key Program of Natural Science Foundation of Heilongjiang Province (ZJN03-5)
文摘PM2 gene （accession number： M80664） with high lysine content from soybean （Glycine max） was found in GenBank by changing three BLASTp parameters. Amino acid composition analysis of PM2 showed that Lys content was on the high level of 18.22%. Protein encoded by PM＇2 also belonged to the family of late embryogenesis abundant （LEA） proteins, which was considered that it had a strong relation with the abiotic stress resistance. In this experiment, PM2 gene was obtained from dry soybean seeds by RT-PCR, plant expression vector pEMTPM2 was constructed, and then transformed into tobacco by using agrobacterium-mediated method. Eight salt and drought tolerant lines were obtained from 31 differentiated lines. Real-time PCR showed that PM2 gene overexpressed in all four PCR positive lines with the osmotic stress resistance. These results confirmed that the overexpression of PM2 gene enhanced the osmotic stress resistance of transgenic tobacco.
