Study Of HSP90 Inhibitor Ganetespib Increasing The Sensitivity Of Mantle Cell Lymphoma Cells To The PARP Inhibitor And Investigation Of The Mechanism

Objective: Mantle cell lymphoma(MCL)is a non-Hodgkin’s lymphoma(NHL)with a high degree of malignancy,the median overall survival of patients is only 3 to5 years.Because of its complicated clinical characteristics,diverse disease progression and frequent relapses,there is no cure at present.Conventional chemotherapy drugs have unignorable side effects on MCL patients and are prone to cause drug resistance.Therefore,it is urgent to develop new therapy strategies.Poly-ADP-ribose polymerase(PARP)inhibitors are a new type of targeted anti-tumor drugs which affect the DNA damage repair in tumor cells,and are more effective in patients with homologous recombination(HR)repair dysfunction.The previous studies of our group found that heat shock protein 90(HSP90)inhibitors can affect the DNA damage repair in tumor cells.Therefore,we hope to explore whether it can be used in combination with PARP inhibitors to enhance the cytotoxicity effects of PARP inhibitors.This thesis aims to investigate whether the second-generation HSP90 inhibitor Ganetespib can enhance the cytotoxity of the PARP inhibitor Olaparib on MCL and to investigate the corresponding mechanism.Methods: First,MCL cell lines Jeko-1 and REC-1 were treated with the HSP90 inhibitor Ganetespib,and the changes of DNA damage repair-related genes were detected by transcriptome sequencing.At the same time,the changes of m RNA expression and protein expression of these genes were verified by qRT-PCR and western Blot,respectively.Then MTT assays were used to detect whether the treatment of Ganetespib enhanced the inhibitory effects of PARP inhibitor Olaparib on proliferation of MCL cells.Flow cytometry and Western blot were used to detect the effects of Ganetespib and Olaparib on cell cycle and apoptosis of MCL cells.Immunofluorescence and western blot were used to detect the effects of drug combination on DNA damage and HR repair of MCL cells.Finally,through the subcutaneous transplantation mouse model of MCL,the effects of drug combination on the growth inhibition of tumors in nude mice and the effects on HR repair were studied.Results: The results of transcriptome sequencing,qRT-PCR,and Western blot experiments showed that Ganetespib inhibited the m RNA and protein expression of HR repair-related genes in MCL cells Jeko-1 and REC-1.And Ganetespib significantly enhances proliferation inhibitory effects of Olaparib on MCL cell lines;it also enhances Olapaib induced apoptosis and cycle arrest of MCL cells.It was also found that Ganetespib treatment can enhance Olaparib-induced DNA damage and inhibit HR repair functions.Therefore,it may lead to the accumulation of cellular DNA damage and apoptosis.The cell cycle-related proteins Cyclin D1 and CDK4 in drug combination group decreased more significantly,and the effects of cell cycle arrest was also more significant in drug combination group.The results of in vivo experiments in mice show that the combined use of Ganetespib and Olaparib can significantly inhibit the growth of subcutaneous transplanted tumors of MCL in mice,and inhibit the protein levels of RAD51 in tumor tissues.Conclusion: In vivo and in vitro studies have shown that the HSP90 inhibitor Ganetespib has an inhibitory effect on DNA damage repair in MCL cells and can enhance Olaparib induced apoptosis and cell cycle arrest in MCL cells.It can also enhance Olaparib induced DNA damage in MCL cells.Therefore,the damaged DNA may not be repaired in time,and it may lead to cell death.This study may provides a novel strategy and insights for the treatment of MCL.