The Clinical Significance Of CRBN Pathway Proteins In Multiple Myeloma Patients

Part ? Expression of CRBN signaling pathway proteins as candidate biomarkers for outcome in myeloma patientsPurposes Multiple myeloma(MM)is a clonal plasma cell malignancy with genetic and clinical heterogeneity,whose incidence rate stands the second place of hematologic malignances.With in-depth study of MM and rapid development of novel anti-MM drugs,survival rate and living quality of MM patients have been greatly improved during the past decade.Cereblon(CRBN),Ikaros(IKZF1),Aialos(IKZF3)and multiple myeloma oncogene 1(MUM1)were important components of CRBN signaling pathway.In previous studies,CRBN was considered as the main target of the anti-MM effect of IMi Ds.In vivo and in vitro experiments confirmed that the sensitivity to IMi Ds was strongly related to CRBN protein level.Therapeutic effect of IMi Ds was almost completely cancelled and IMi Ds-resistant cells formed if CRBN was knocked down or down-regulated.In this study,we evaluate the expression level of CRBN signaling pathway protein in newly diagnosed MM patients,and to further analyze the relationship between the efficacy and prognosis of patients.Methods In this study,we evaluated CRBN signaling pathway proteins expression level in bone marrow(BM)by immunohistochemical(IHC)staining in 123 newly diagnosed MM patients.We also reviewed medical records and investigated the relationship between expression level and treatment outcome.Results 1.After treated with IMi Ds,patients with high level of CRBN and MUM1 achieved better overall response rate than those expressed low level(CRBN,88.0% vs.42.3%,P=0.001;MUM1,83.3% vs.43.1%,P=0.009).2.1)Patients with CRBN and MUM1 overexpression also had better overall survival(median OS,CRBN,not reached vs.21.0 months,P=0.004;MUM1,both are not reached,P=0.021)and progression free survival(median PFS,CRBN,28.0 vs.12.0 months,P=0.002;MUM1,32.0 vs.12.0,P<0.001)than patients with low level,as well as 2-year OS rate(CRBN,86% vs.44%,P=0.005;MUM1,81% vs.51%,P=0.003)and PFS rate(CRBN,66% vs.17%,P=0.001;MUM1,63% vs.20%,P<0.001).2)In high CRBN expression group,patients treated with IMi Ds had a higher 2-year OS and PFS rate than those treated with Bortezomib(OS,86% vs.68%,P=0.079;PFS,66% vs.45%,P=0.04).3)In high MUM1 expression group,patients treated with IMi Ds had a better OS(not reached vs.34.0 months,P=0.021)and PFS(32.0 vs.16.0 months,P=0.017)than patients with low level,as well as 2-year OS(81% vs.58%,P=0.014)rate and PFS rate(63% vs.36%,P=0.003).Conclusions The protein expression level of CRBN signaling pathway is significantly correlated with the efficacy and prognosis of MM patients receiving IMi Ds treatment.Patients with high level of CRBN or MUM1 had a better overall response and survival.Part ? Combination of clarithromycin and lanalidomide synergistically inhibits proliferation of multiple myeloma cells through CRBN signaling pathwayPurposes Multiple myeloma(MM)is a kind of heterogeneous plasma cells malignant which is characterized by bone disease,impaired renal function,anemia and hypercalcaemia.However,there is still a great difference in the prognosis of MM patients.CRBN signaling pathway is a direct target for immunomodulatory and antiproliferative activities of lenalidomide.Expression of CRBN signaling pathway proteins play an important role for patients' sensitivity to IMi Ds.Our research aims to identify the effect and potential mechanism of combination clarithromycin with lenalidomide.Methods We detected cell proliferation rates by CCK8 assay,cell cycle and apoptosis by flow cytometric analysis,m RNA expression of CRBN signaling pathway by q RT-PCR and expression of proteins by Western blot.Results Cell growth assays showed that combination of clarithromycin and lenalidomide synergistically induced growth inhibition of MM cell line.Flow cytometric analysis found that their combination dramatically increased G0/G1 phase arrest.Western blot assays revealed that combination clarithromycin with lenalidomide decreased CRBN signaling pathway proteins level,especially CRBN,IKZF3 and IRF4 levels.Conclusion There is a synergistical effect when combination of lenalidomide with clarithromycin.Combination effect increased the degradation of CRBN signaling pathway proteins.