Objective： To investigate the effect of berberine, one of the main alkaloids of Rhizoma coptidis, on myocardial morphology and the expressions of cyclin-dependent kinase 9 （Cdk9） and cyclin T1 protein in the myocar...Objective： To investigate the effect of berberine, one of the main alkaloids of Rhizoma coptidis, on myocardial morphology and the expressions of cyclin-dependent kinase 9 （Cdk9） and cyclin T1 protein in the myocardium of type 2 diabetic rats. Methods： Type 2 diabetes mellitus rats were induced by an injection of 35 mg/kg streptozotocin （STZ） and a high-carbohydrate/high-fat diet for 16 weeks. Diabetic rats were given low-, middle-, high-dose berberine （75, 150, 300 mg/kg）, fenofibrate （100 mg/kg） and rosiglitazone （4 mg/kg） for another 16 weeks, respectively. The myocardium structure was observed with hematoxylin ＆ eosin （H＆E） staining and Cdk9 and cyclin T1 protein expressions were detected by immunohistochemistry. Results： Middle-dose, high-dose berberine improved myocardial hypertrophy and interstitial fibrosis of diabetic rats. Cdk9 and cyclin T1 protein were significantly lower in diabetic myocardium than in control one （P〈0.01）, and middle-dose, high-dose berberine and fenofibrate obviously increased both Cdk9 and cyclin T1 expression to near control level （P〈0.01）. Conclusion： Berberine modulates Cdk9 and cyclin T1 protein expression in diabetic myocardium which may contribute to ameliorate myocardium damage.展开更多
The aberrant overexpression of cyclin-dependent kinase 9 (CDK9) in cancer cells results in the loss of proliferative control, making it an attractive therapeutic target for various cancers. However, the highly structu...The aberrant overexpression of cyclin-dependent kinase 9 (CDK9) in cancer cells results in the loss of proliferative control, making it an attractive therapeutic target for various cancers. However, the highly structural similarity between CDK9 and CDK2 makes the development of novel selective CDK9 inhibitors a challenging task and thus limits their clinical applications. Here, an effective two-stage virtual screening strategy was developed to identify novel CDK9 inhibitors with better inhibitory activity and higher selectivity. The first screening stage aims to select potential compounds with better inhibitory activity than Roniciclib, one of the most effective CDK9 inhibitors, through reliable structure-based pharmacophoric virtual screening and accurate molecular docking analyses. The second stage employs a very detailed visual inspection process, in which several structural criteria describing the major difference between the binding pockets of CDK9 and CDK2 are taken into consideration, to identify compounds with higher selectivity than CAN508, one of the CDK9 inhibitors with distinguished selectivity. Finally, three compounds (NCI207113 from NCI database and TCM0004 and TCM3282 from TCM database) with better inhibitory activity and higher selectivity were successfully identified as novel CDK9 inhibitors. These three compounds also display excellent binding stabilities, great pharmacokinetic properties and low toxicity in MD simulations and ADMET predictions. Besides, the results of binding free energy calculations suggest that enhancing van der Waals interaction and nonpolar solvation energy and/or reducing polar solvation energy can significantly improve the binding affinity of these CDK9 inhibitors. Their clinical potentials to serve as anticancer drug candidates can be further evaluated through a series of <em>in vitro/in vivo</em> bioassays in the future. To the best of our knowledge, this is the first attempt to identify novel CDK9 inhibitors with both better inhibitory activity and higher selectivity through an effective two-stage virtual screening strategy.展开更多
Venetoclax,an FDA-approved Bcl-2 selective inhibitor for the treatment of chronic lymphocytic leukemia and acute myeloid leukemia(AML),is tolerated well in elderly patients with AML and has good overall response rates...Venetoclax,an FDA-approved Bcl-2 selective inhibitor for the treatment of chronic lymphocytic leukemia and acute myeloid leukemia(AML),is tolerated well in elderly patients with AML and has good overall response rates;however,resistance remains a concern.In this study,we show that targeting CDK9 with voruciclib in combination with venetoclax results in synergistic antileukemic activity against AML cell lines and primary patient samples.CDK9 inhibition enhances venetoclax activity through downregulation of Mcl-1 and c-Myc.However,downregulation of Mcl-1 is transient,which necessitates an intermittent treatment schedule to allow for repeated downregulation of Mcl-1.Accordingly,an every other day schedule of the CDK9 inhibitor is effective in vitro and in vivo in enhancing the efficacy of venetoclax.Our preclinical data provide a rationale for an intermittent drug administration schedule for the clinical evaluation of the combination treatment for AML.展开更多
Triple-negative breast cancer(TNBC)is a highly aggressive and metastasizing cancer that has the worst prognosis out of all breast cancer subtypes.The epithelial emesenchymal transition(EMT)and cancer stem cells(CSCs)h...Triple-negative breast cancer(TNBC)is a highly aggressive and metastasizing cancer that has the worst prognosis out of all breast cancer subtypes.The epithelial emesenchymal transition(EMT)and cancer stem cells(CSCs)have been proposed as important mechanisms underlying TNBC metastasis.CDK9 is highly expressed in breast cancer,including TNBC,where it promotes EMT and induces cancer cell stemness.In this study,we have identified a tetrahydroisoquinoline derivative(compound 1)as a potent and selective CDK9-cyclin T1 inhibitor via virtual screening.Interestingly,by targeting the ATP binding site,compound 1 not only inhibited CDK9 activity but also disrupted the CDK9-cyclin T1 proteineprotein interaction(PPI).Mechanistically,compound 1 reversed EMT and reduced the ratio of CSCs by blocking the CDK9-cyclin T1 interaction,leading to reduced TNBC cell proliferation and migration.To date,compound 1 is the first reported tetrahydroisoquinoline-based CDK9-cyclin T1 ATP-competitive inhibitor that also interferes with the interaction between CDK9 and cyclin T1.Compound 1 may serve as a promising scaffold for developing more selective and potent anti-TNBC agents.Our work also provides insight into the role of the CDK9-cyclin T1 PPI on EMT and CSCs and highlights the feasibility and significance of targeting CDK9 for the treatment of TNBC.展开更多
MYC is an oncogenic transcription factor with a novel role in enhancing global transcription when overexpressed. However, how MYC promotes global transcription remains controversial. Here, we used a series of MYC muta...MYC is an oncogenic transcription factor with a novel role in enhancing global transcription when overexpressed. However, how MYC promotes global transcription remains controversial. Here, we used a series of MYC mutants to dissect the molecular basis for MYC-driven global transcription. We found that MYC mutants deficient in DNA binding or known transcriptional activation activities can still promote global transcription and enhance serine 2 phosphorylation(Ser2P) of the RNA polymerase(Pol) II Cterminal domain(CTD), a hallmark of active elongating RNA Pol II. Two distinct regions within MYC can promote global transcription and Ser2P of Pol II CTD. The ability of various MYC mutants to promote global transcription and Ser2P correlates with their ability to suppress CDK9 SUMOylation and enhance positive transcription elongation factor b(P-TEFb) complex formation. We showed that MYC suppresses CDK9 SUMOylation by inhibiting the interaction between CDK9 and SUMO enzymes including UBC9 and PIAS1. Furthermore, MYC's activity in enhancing global transcription positively contributes to its activity in promoting cell proliferation and transformation. Together, our study demonstrates that MYC promotes global transcription, at least in part, by promoting the formation of the active P-TEFb complex via a sequence-specific DNA-binding activity-independent manner.展开更多
文摘Objective： To investigate the effect of berberine, one of the main alkaloids of Rhizoma coptidis, on myocardial morphology and the expressions of cyclin-dependent kinase 9 （Cdk9） and cyclin T1 protein in the myocardium of type 2 diabetic rats. Methods： Type 2 diabetes mellitus rats were induced by an injection of 35 mg/kg streptozotocin （STZ） and a high-carbohydrate/high-fat diet for 16 weeks. Diabetic rats were given low-, middle-, high-dose berberine （75, 150, 300 mg/kg）, fenofibrate （100 mg/kg） and rosiglitazone （4 mg/kg） for another 16 weeks, respectively. The myocardium structure was observed with hematoxylin ＆ eosin （H＆E） staining and Cdk9 and cyclin T1 protein expressions were detected by immunohistochemistry. Results： Middle-dose, high-dose berberine improved myocardial hypertrophy and interstitial fibrosis of diabetic rats. Cdk9 and cyclin T1 protein were significantly lower in diabetic myocardium than in control one （P〈0.01）, and middle-dose, high-dose berberine and fenofibrate obviously increased both Cdk9 and cyclin T1 expression to near control level （P〈0.01）. Conclusion： Berberine modulates Cdk9 and cyclin T1 protein expression in diabetic myocardium which may contribute to ameliorate myocardium damage.
文摘The aberrant overexpression of cyclin-dependent kinase 9 (CDK9) in cancer cells results in the loss of proliferative control, making it an attractive therapeutic target for various cancers. However, the highly structural similarity between CDK9 and CDK2 makes the development of novel selective CDK9 inhibitors a challenging task and thus limits their clinical applications. Here, an effective two-stage virtual screening strategy was developed to identify novel CDK9 inhibitors with better inhibitory activity and higher selectivity. The first screening stage aims to select potential compounds with better inhibitory activity than Roniciclib, one of the most effective CDK9 inhibitors, through reliable structure-based pharmacophoric virtual screening and accurate molecular docking analyses. The second stage employs a very detailed visual inspection process, in which several structural criteria describing the major difference between the binding pockets of CDK9 and CDK2 are taken into consideration, to identify compounds with higher selectivity than CAN508, one of the CDK9 inhibitors with distinguished selectivity. Finally, three compounds (NCI207113 from NCI database and TCM0004 and TCM3282 from TCM database) with better inhibitory activity and higher selectivity were successfully identified as novel CDK9 inhibitors. These three compounds also display excellent binding stabilities, great pharmacokinetic properties and low toxicity in MD simulations and ADMET predictions. Besides, the results of binding free energy calculations suggest that enhancing van der Waals interaction and nonpolar solvation energy and/or reducing polar solvation energy can significantly improve the binding affinity of these CDK9 inhibitors. Their clinical potentials to serve as anticancer drug candidates can be further evaluated through a series of <em>in vitro/in vivo</em> bioassays in the future. To the best of our knowledge, this is the first attempt to identify novel CDK9 inhibitors with both better inhibitory activity and higher selectivity through an effective two-stage virtual screening strategy.
文摘Venetoclax,an FDA-approved Bcl-2 selective inhibitor for the treatment of chronic lymphocytic leukemia and acute myeloid leukemia(AML),is tolerated well in elderly patients with AML and has good overall response rates;however,resistance remains a concern.In this study,we show that targeting CDK9 with voruciclib in combination with venetoclax results in synergistic antileukemic activity against AML cell lines and primary patient samples.CDK9 inhibition enhances venetoclax activity through downregulation of Mcl-1 and c-Myc.However,downregulation of Mcl-1 is transient,which necessitates an intermittent treatment schedule to allow for repeated downregulation of Mcl-1.Accordingly,an every other day schedule of the CDK9 inhibitor is effective in vitro and in vivo in enhancing the efficacy of venetoclax.Our preclinical data provide a rationale for an intermittent drug administration schedule for the clinical evaluation of the combination treatment for AML.
基金This work was supported by the Health and Medical Research Fund(No.HMRF/14150561)the National Natural Science Foundation of China(No.201575121 and 21775131)+3 种基金the Hong Kong Baptist University Century Club Sponsorship Scheme 2020,Teaching Development Fund(No.TDG/1920/02)the Science and Technology Development Fund,Macao SAR,China(File no.0072/2018/A2 and 0007/2020/A1)SKLQRCM(UM)-2020-2022the University of Macao,China(MYRG2019e00002eICMS).
文摘Triple-negative breast cancer(TNBC)is a highly aggressive and metastasizing cancer that has the worst prognosis out of all breast cancer subtypes.The epithelial emesenchymal transition(EMT)and cancer stem cells(CSCs)have been proposed as important mechanisms underlying TNBC metastasis.CDK9 is highly expressed in breast cancer,including TNBC,where it promotes EMT and induces cancer cell stemness.In this study,we have identified a tetrahydroisoquinoline derivative(compound 1)as a potent and selective CDK9-cyclin T1 inhibitor via virtual screening.Interestingly,by targeting the ATP binding site,compound 1 not only inhibited CDK9 activity but also disrupted the CDK9-cyclin T1 proteineprotein interaction(PPI).Mechanistically,compound 1 reversed EMT and reduced the ratio of CSCs by blocking the CDK9-cyclin T1 interaction,leading to reduced TNBC cell proliferation and migration.To date,compound 1 is the first reported tetrahydroisoquinoline-based CDK9-cyclin T1 ATP-competitive inhibitor that also interferes with the interaction between CDK9 and cyclin T1.Compound 1 may serve as a promising scaffold for developing more selective and potent anti-TNBC agents.Our work also provides insight into the role of the CDK9-cyclin T1 PPI on EMT and CSCs and highlights the feasibility and significance of targeting CDK9 for the treatment of TNBC.
基金supported by the National Natural Science Foundation of China (32070643, 32130051, 31961133009)Science and Technology Commission of Shanghai Municipality (20JC1411500)+3 种基金the ECNU Public Platform for Innovation (011)the Instruments Sharing Platform of the School of Life Sciences,East China Normal Universitysupported by the US National Institutes of Health (NIH) grant 1RO1CA251698-01Cancer Prevention and Research Institute of Texas (CPRIT) grant RP190077。
文摘MYC is an oncogenic transcription factor with a novel role in enhancing global transcription when overexpressed. However, how MYC promotes global transcription remains controversial. Here, we used a series of MYC mutants to dissect the molecular basis for MYC-driven global transcription. We found that MYC mutants deficient in DNA binding or known transcriptional activation activities can still promote global transcription and enhance serine 2 phosphorylation(Ser2P) of the RNA polymerase(Pol) II Cterminal domain(CTD), a hallmark of active elongating RNA Pol II. Two distinct regions within MYC can promote global transcription and Ser2P of Pol II CTD. The ability of various MYC mutants to promote global transcription and Ser2P correlates with their ability to suppress CDK9 SUMOylation and enhance positive transcription elongation factor b(P-TEFb) complex formation. We showed that MYC suppresses CDK9 SUMOylation by inhibiting the interaction between CDK9 and SUMO enzymes including UBC9 and PIAS1. Furthermore, MYC's activity in enhancing global transcription positively contributes to its activity in promoting cell proliferation and transformation. Together, our study demonstrates that MYC promotes global transcription, at least in part, by promoting the formation of the active P-TEFb complex via a sequence-specific DNA-binding activity-independent manner.
