The Reserch On MiRNAs As Markers Of Diagnosis And Drug Resistance Of Multiple Myeloma

Objective: To evaluate whether the abnormal expression of serum mi RNAs can be used as the diagnosis of multiple myeloma marks; To analyze the abnormal expression of mi RNAs in drug resistance of myeloma chemotherapy; To explore the mi RNAs as targets by inhibiting the targeted mi RNAs expression to increase the possibility of chemotherapy sensitivity, and further analyze the molecular mechanism.Methods: The expression of mi RNAs, includes mi R29 a, mi R155, mi R16, mi R92 a were measured by q RT-PCR in multiple myeloma patients serum. And the change of serum mi R29 a in case observation was also investigated by q RT-PCR. The doxorubicin RPMI8226 cell lines(RPMI8226/DOX) was established by culturing 8226 cells with continuous low concentration and intermittent gradually increasing concentration of doxorubicin in vitro, the expression of mi R155, FOXO3 a and E-cadherin m RNAs were measured by q RT-PCR and the FOXO3 a and BCL-2 protein expression was detected by Western blot in RPMI8226 cell lines. The RPMI8226/DOX cells were treated with certain concentration of mi R155 Inhibitor and Mimic for 48 h and 72 h, and CCK8 to measure proliferation and inhibition ratio. The m RNA expression of mi R155、FOXO3a and E-cadherin were detected by RT-PCR. The FOXO3 a and BCL-2 protein were detected by Western blot.Results: The results showed that mi R-29 a, miR155 and mi R-16 can not discriminate between MM and HD alone; while the combination of mi R-29 a and mi R155 was demonstrated to be an effective biomarker for distinguishing MM from HD, with an AUC(area under of ROC curve) of 0.8739, sensitivity of 80.77%, and specificity of 83.33%. Case observation showed that the expression level of mi R-29 a in MM decreased as chemotherapy progressed, the same with the change of plasma cells and M protein. The level of mi R155 m RNA and BCL-2 protein expression was obviously upregulated in RPMI8226/DOX, but decreased in FOXO3 a and E-cadherin expression compared with RPMI8226 cells. The proliferation of RPMI8226/DOX wasobviously decreased after certain concentration of mi R155 Inhibitor for 72 h. MiR155 Inhibitor mediated a significant decrease of m RNA expression of mi R155 and the protein expression of BCL-2, and increase of m RNA expression of E-cadherin and the protein expression of FOXO3. Mi R155 Inhibitor can decrease the DOX IC50 of RPMI8226/DOX, but mi R155 Mimic can increase the IC50.Conclusions: 1.The abnormal expression of serum mi RNAs can be used as diagnostic markers for multiple myeloma; mi R29a/mi R155 can be used as the diagnosis mark of multiple myeloma. 2. The abnormal expression of mi R155 is closely associated with the chemotherapy drug-resistance of multiple myeloma and its mechanism may be related to the cancer gene FOXO3 a, the generation of EMT and the antiapoptotic gene expression of BCL-2. 3. The targeted inhibition mi R155 expression can increase the chemotherapy sensitivity of multiple myeloma cells, its mechanism is by inhibiting the expression of mi R155 increase FOXO3 a cancer gene expression, reverse EMT generated, and decrease the BCL-2 protein expression. 4. It is a new way of mi RNAs to overcome the chemotherapy drug-resistance of multiple myeloma.