NAMPT Regulates TP53-Mutated Mantle Cell Lymphoma Chemosensitivity By Targeting The DNA Damage Response Pathway

Background: Mantle cell lymphoma has the biological characteristics of aggressive lymphoma and the incurable characteristics of indolent lymphoma.This disease has a poor prognosis and is prone to relapse,with a 5-year survival rate of only 34% in highrisk patients.Therefore,it is essential to find new therapeutic targets,overcome drug resistance and improve the efficacy of MCL.Previous genetic sequencing studies of mantle cell lymphoma have found that the DNA damage response(DDR)pathway may play a vital role in the initiation and development of MCL.In contrast,P53,an essential protein in the DNA damage response pathway,is an independent prognostic factor for MCL.Compared with TP53 wild-type patients,patients with TP53 mutations have more clinical features,shorter progression-free survival(PFS)and overall survival(OS),and are more difficult to treat clinically.Nicotinamide phosphoribosyl transferase(NAMPT),a limiting enzyme in the NAD salvage pathway,regulates the metabolism and NAD synthesis of malignant tumor cells and has been considered an ideal anticancer target in recent years.Previous studies in our group have shown that NAMPT is highly expressed in indolent lymphoma and can affect the sensitivity of alkylating agents by regulating the DDR pathway.However,it is not reported whether NAMPT plays a role in the development and progression of MCL patients and whether it affects the prognosis and clinical treatment efficacy.Objective: Patients with TP53 mutations in MCL have shorter PFS and OS and a poor prognosis and are currently a clinical treatment challenge.Therefore,it is imperative to find new treatment targets and further improve the efficacy of MCL.Methods:This study selects four MCL cell lines,TP53 mutant cells Mino and Jeko-1,and TP53 wild-type cells Granta-519 and Z138.The specific research through the following experiments to carry out:1.To explore the expression of NAMPT Protein in lymphoma using the Human Protein Atlas and GEPIA databases.Moreover,it explores the correlation between expression and clinical prognosis.2.Collected the clinical and pathological features of 16 patients with MCL in the recent ten years from the Department of Oncology,the Second Hospital of Medical University.Immunohistochemistry detects the expression of NAMPT and P53.Retrospectively analyze the correlation between NAMPT and P53 expression and the expression correlation between the clinical pathological characteristics and the survival prognosis.3.Cell proliferation assay detects the growth inhibitory effects of KPT-9274,a NAMPT inhibitor,on four MCL cell lines.Flow cytometry detects the percentage of apoptotic cells in different treatment groups.Western blot analysis the changes of apoptosis pathway-related proteins in different treatment groups.4.Use Quantitative proteomics analysis of the proteins of mutant TP53 cells Mino and wild-type TP53 cells Z138 treated with NAMPT inhibitor 48 h.The differential proteins carry out the functional cluster analysis.5.Cell proliferation assay detects the growth inhibition of NAMPT inhibitor KPT-9274 combined with Bendamustine on TP53 mutant Mino cells and TP53 wild-type Z138 cells.The apoptosis test detects the percentage of apoptotic cells,and Western blot analysis the changes of DDR pathway-related proteins.6.Cell proliferation assay examines the effect of the combination of NAMPT inhibitor KPT-9274 and DDR pathway targeting drug on the proliferation of TP53 mutant Mino cells.Results:1.NAMPT is highly expressed in mantle cell lymphoma,and high expression of NAMPT is associated with poor prognosis.Inhibition of NAMPT function can significantly inhibit the proliferation of MCL cells and induce apoptosis.2.Inhibition of NAMPT function in TP53 mutant MCL cells induced DNA damage accumulation and downregulated DNA damage repair function.Inhibition of NAMPT in TP53 wild-type MCL cells mainly affects BCR and immune-related pathways.3.Inhibition of NAMPT down-regulated DNA homologous recombination repair in MCL cells enhanced Bendamustine sensitivity.4.Inhibition of NAMPT function in TP53-mutated MCL cells enhanced the sensitivity of DDR pathway-targeting drugs AZD2281(PARP inhibitor),AZD7762(Chk1 inhibitor),and AZD1775(WEE1 inhibitor).Conclusion:1.NAMPT can be a new target for mantle cell lymphoma therapy.2.NAMPT has a different mechanism of action in mantle cell lymphoma with different TP53 mutation statuses.3.Inhibition of NAMPT function enhanced the sensitivity of Bendamustine.The combination with small molecule inhibitors of the DDR pathway is also expected to be a novel scheme for TP53 mutant MCL.