The Research of Specific Inhibition of Survivin Expression To Reverse Drug Resistance with RNA Interference Technology.

Objective:Use RNA interference technology to down-regulate the expression of survivin gene in KM3 cells, observe its induction of apoptosis of KM3 cells, and if it can increase chemotherapy sensitivity of KM3 cells to adriamycin.

Methods: SiRNA designed and in-vitro chemosynthesized aiming to survivin was transfected into human myeloma cell line KM3 mediated by liposome. Survivin mRNA transcription and protein expression of KM3 cells were then detected using RT-PCR and Western-blot 24, 48 and 72 hours after transfection, so as to invest the silencing effect. Besides, the apoptosis of the cell line were observed under fluorescence microscopy before and after transfection. Furthermore, cytotoxic analysis was used to compare the sensitivity variation of KM3 cells to adriamycin before and after transfection.

Results: Down-regulations of survivin mRNA transcription and protein expression of KM3 cells could be observed 24 hours after siRNA tranfection, which were (12±2.3)% and (9.4±1.8)% respectively. After 48 hours, they were (61.4±7.9)% and (38.6±6.7)% respectively, while the survivin mRNA transcription and protein expression was increased quickly 72 hours later. Under fluorescence microscopy, the apoptosis rate of KM3 cells transfected with survivin siRNA 48 hours later was 28±7%, which was significantly higher than the control cells. (P<0.05). The IC50 value of KM3 cells to adriamycin decreased from 1.12±0.14uM to 0.21±0.03uM, which means the sensitivity of KM3 cells to adriamycin was 5.3 fold increased.

Conclusions: SiRNA which was designed and synthesized to target survivin could effectively down-regulate survivin mRNA transcription and protein expression in KM3 cells, induce KM3 cells to apoptosis, increase its sensitivity to adriamycin after down-regulation, and effectively reverse drug-resistance of MM cells.