Design And Find Novel BTK/HDAC Dual Target Inhibitors To Treat Mantle Cell Lymphoma

Mantle cell lymphoma(MCL)is a non-Hodgkin lymphoma(NHL)with a high degree of malignancy and poor prognosis.It is characterized by chromosome translocation t(11;14)(q13;q32)which lead to overexpression of cyclin D1.MCL is mostly invasive clinically,and it is still an incurable lymphoma.There is no standard first-line chemotherapy.Compared with other B-cell lymphomas,MCL is difficult to maintain long-term efficacy through chemotherapy.In recent years,with the in-depth study of the pathogenesis of MCL,molecular targeted therapy has made some progress,including mTOR inhibitors,BTK inhibitors,HDAC inhibitors and CDK inhibitors.BTK is a regulatory factor downstream of the B cell receptor signaling pathway,which plays a crucial role in the development and maturation of B cells.Abnormal expression and activation of BTK are prevalent in MCL cells.Ibrutinib(IBN)is the first listed BTK inhibitor,which has shown good clinically therapeutic effect on MCL.The FDA approved it for the treatment of relapse-refractory MCL.With the wide range of clinical applications,the drug resistance of ibrutinib appears gradually.The cysteine mutation at the site of BTK481 is serine,and about one third of patients have no response for treatment of ibrutinib.At present,how to improve the overall response rate and improve drug resistance in this group of patients is a hot topic in MCL therapy research.The abnormal expression and mutation of HDAC are closely related to the occurrence and development of tumor.High expression of HDAC in lymphoma results in low acetylation of histone.Therefore,inhibition of HDAC can arrest cell cycle and induce apoptosis.Vorinostat(SAHA)was the first commercially available HDAC inhibitor and was approved by the FDA for the treatment of cutaneous T-cell lymphoma.Clinical trials show that the use of vorinostat in the treatment of relapsed refractory MCL shows a certain therapeutic effect,but the effect of a single drug is limited.At present,the clinical treatment of MCL patients with multiple combinations of treatment.It has been reported in the literature that BTK inhibitors and HDAC inhibitors show a good synergistic effect in MCL cells,manifesting in inhibition of the NF-kB pathway and downregulation of cyclin D1.Moreover,there are no reports of dual target inhibition of BTK/HDAC in the literature.Based on a thorough analysis of proteins and ligands,we adopted the method of molecular fusion to retain the basic skeleton of 3-(4-phenoxyphenyl)-4-aminopyrazolopyrimidine in Ibrutinib as a Cap group,introduced a functional group capable of chelating with zinc ions(ZBG),and optimized the Linker part of the linker between the two parts.We synthesized a total of 20 novel BTK/HDAC dual target inhibitors in three series,of which 10 are YB series of terminal hydroxamic acids and 4 are YK series of o-phenylenediamine and 6 are YS series of carboxylic acids.We performed preliminary in vitro bioactivity evaluations on these 20 compounds,including inhibition of BTK,inhibition of HDAC,on Jurkat cells and mantle cell lymphoma cells(Rec-1,Jeko-1,Marver-1,Z138,Mino)anti-proliferative effects.All three series showed good inhibitory activity against BTK,and the inhibition rate was greater than 90%at a concentration of 1μM.However they did not reach the level of the lead compound IBN(IC50=8 nM),we speculated it was due to the removal of the acrylamide side chains in IBN structure which could attach of Cys-481.In an in vitro HDAC inhibitory activity assay,compound YB1 showed comparable HDAC inhibitory activity to the positive control SAHA,which was superior to YK1.In vitro antiproliferative activity assay of Jurkat cells,YB and YK series showed good growth inhibitory activity,YK series activity was slightly better than YB series,in which YK1 showed better anti-proliferation activity than the positive control SAHA and IBN.In the growth inhibitory activity assay of multiple mantle cell lymphomas,compounds YB1,YB7,and YK1 all showed good antiproliferative activity,especially YB1 and YK1 showed significantly better results than the positive control drug IBN.Moreover,the anti-proliferative activity of YB1 on BTK-resistant Maver-1 and Z138 MCL cells was 17 and 19 times higher than IBN,respectively,which we speculated was due to the dual inhibition of BTK and HDAC leading to the synergistic apoptosis.Finally,we tested the selectivity of compound YB1 against other 26 kinases at a concentration of 1 μM.The results showed that YB1 showed a strong inhibitory effect on Bmx and Tec of the same kinase family as BTK.