The Combination Of Drugs In Treating B-cell Malignancies: Pre-clinical Study

PART ?:MK2206 enhances the cytocidal effects of bufalin in Multiple Myeloma by inhibiting the AKT/m TOR pathwayDespite the development of promising cancer therapeutic drugs,multiple myeloma(MM)remains an incurable disease.Bufalin is a bufanolide steroid compound of the traditional Chinese medicine Chan Su that was previously shown to exert growth suppression effects on myeloma cell lines.Previous studies conducted by our group demonstrated that bufalin activated the AKT/m TOR pathway in myeloma cells,which is considered an essential pathway to disease progression and is related to drug resistance in MM.In view of the significant role of AKT in MM,the allosteric AKT inhibitor MK2206 was selected in order to enhance the antitumor effects of bufalin in different MM cell lines(NCI-H929,U266,LP-1,RPMI-8226).The data indicated that MK2206 enhanced the cytotoxicity of bufalin in MM cells,via the suppression of cellular proliferation and the induction of apoptosis,as demonstrated by cleavage of apoptosis-related proteins.This effect was further noted in the presence of exogenous interleukin-6 and/or following the co-culture of MM cells with bone marrow stromal cells(BMSC).This process was associated with the inhibition of the AKT/m TOR pathway.The combination of bufalin with MK2206 reduced the secretion of IL-6 in U266 cells.The combined treatment exhibited similar anti-MM effects in bortezomib-resistant cell lines(NCI-H929 R,U266R).In addition to the in vitro cell line models,the synergistic effect was noted in primary MM cells and in MM xenografts of BALB-c and NOD-SCID mice.In conclusion,the data suggested that MK2206 significantly enhanced the cytocidal effects of bufalin in MM cells,regardless of the sensitivity to bortezomib,via the inhibition of the AKT/m TOR pathway.The study provided the basis of a promising treatment approach for MM.PART ?:In vivo study of Lenalidomide combined with Thirdgeneration CART19 in the treatment of diffuse large B-cell lymphomaChimeric antigen receptor T cells recognizing CD19(CART19)is a novel tumor immunotherapy for the treatment of refractory B-cell malignancies;complete remission rate in relapsed/refractory B-cell acute lymphoblastic leukemia(B-ALL)reaches 80 %,however only 40 % in relapse/refractory diffuse large B-cell lymphoma(DLBCL).Lenalidomide is an immunomodulatory drug currently approved by FDA for the treatment of multiple myeloma(MM)and mantle cell lymphoma(MCL),while it is clinically tested in the therapy of ABC-DLBCL.In order to enhance the effectiveness of CART19 in DLBCL,we assessed the anti-lymphoma efficacy of combining Lenalidomide with CART19 using various murine models of DLBCL.In GCB or ABC-DLBCL PDX model,Lenalidomide enhanced antitumor activity of CART19 cells by antiangiogenesis and improving the infiltration of CART19 cells in tumor tissues.In a xenograft ABC-DLBCL model,combination with Lenalidomide clearly enhanced the antitumor effect of CART19 cells via increasing the number of circulating CART19 cells and the distribution of CD8 central memory T cells,meanwhile reducing the expression of PD1 and TIM3.The in vivo results were similiar with our previous studies.In summary,combining lenalidomide with CART19 cells represents a rational way to incorporate two of the most recent therapies in DLBCL.