The Study Of Bcl-2 Network Based Apoptosis Induction By Bcl-2 Inhibitors And Hsp70 Inhibitors

The cancer burden continues to grow globally and is among the leading causes of death.Targeted therapy is the most useful and a cornerstone therapy recently,which request the identification of cancer specific proteins as targets.The Bcl-2 protein family has been discovered to be essential in cancer growth and metastasis.The protein-protein interactions(PPIs)between more than 20 Bcl-2 members determine cell fate.Additionally,the post-modification of Bcl-2 render the network more complexity,which are under extensive investigation.Hsp70,an ATP-dependent chaperone,is a protein that is activated in response to a wide range of physiological and environmental insults,including anti-cancer chemotherapy,allowing the cell to survive lethal conditions.Although Hsp70 level has been found to be elevated in cancer cells and helps in chemotherapy resistance,it itself cannot behave as a therapeutic target due to its physical functions.Hsp70 has been found to be a new BH3 receptor where its interaction with Bim was revealed.They bound in vitro and in cells through the BH3 domain,and this interaction was suspected to have a major role in chemotherapy resistance.The current study investigate how Bcl-2 networks involved phosphorylation Bcl-2 protein and Hsp70 protein contribute to cancer.Firstly,we used Bcl-2 and Hsp70 inhibitors in cervical and breast cancer cell lines to target these essential proteins.In the cervical cancer trial,seven cervical cancer cell lines were used to assess the ABT-199/Paclitaxel combination strategy.Combination treatment assays were used to evaluate the combination effect by calculating the combination index(CI).Using poly(ADP-ribose)polymerase(PARP)cleavage and CoImmunoprecipitation assays,the mechanism by which the ABT-199 and paclitaxel combination elicits synergistic effects was investigated.The association between the c-Jun N-terminal kinase(JNK)level and the CI value in cancer cells was examined to provide a preliminary evaluation of the JNK1 protein as a biomarker to forecast the combination effect of ABT-199/paclitaxel.Consequently,the Hsp70 inhibitor S1g-6,which was developed by our group to specifically disrupt Hsp70/Bim,was tested on two breast cancer cell lines to see how it affected the cancer.Cell viability,Co-Immunoprecipitation and western blot assays were used to investigate the mechanism of S1g-6 in Tamoxifen-resistant breast cancer cells to determine its efficacy.Hsp70-Bim PPI was developed to provide increased defence against apoptosis in breast cancer cells as well as increased levels of ER α-36 independent resistance to endocrine therapy.In Breast cancer cells resistant to tamoxifen,S1g-6 destabilizes ER α-36 and inhibits ER signalling.Tamoxifen-resistant breast cancer cells respond better to S1g-6 than Tamoxifensensitive breast cancer cells.For breast cancer cells that are resistant to Tamoxifen,combining S1g-6 with Tamoxifen resulted in a synergetic inhibition effect.In Tamoxifen-resistant Er α+breast cancer,the HSP70/Bim complex was discovered to play a key role.Tamoxifen-resistant cells are re-sensitized to Tamoxifen when HSP70/Bim is inhibited.Inhibitors of Bcl-2 and Hsp-70 provide therapeutic hope for cancer treatment.