Mechanism of all-transretinoic acid increasing retinoblastoma sensitivity to vincristine.

Abstract

To explore the mechanism of all-transretinoic acid (ATRA) increasing retinoblastoma (RB) sensitivity to vincristine, and the inhibiting effect of vincristine combined with ATRA treatment on the SO-RB50cell proliferation. SO-RB50cells were cultivated by routine culture method. Different concentrations of vincristine or ATRA were added into culture solution. After 48h, cell counting kit-8 was used to detect the median inhibitory concentration (IC50) of vincristine combined with ATRT treatment to SO-RB50cells. SO-RB50cells were divided into drug combination group, vincristine group, ATRA group and control group. Different drugs were added into the culture solution respectively for cell culture based on the IC50 value. Cell counting kit-8 was used to detect the cell proliferation every 24-h cultivation. After continuous determination for 6d, data was processed to draw the cell growth curve. After drug use for 72h, flow cytometry was used to detect the proportion of different cell cycles of SO-RB50cells in each group. After drug use for 48h, annexin V/propidium iodide method was used to detect the SO-RB50cell apoptosis in each group. The IC50 value of vincristine treatment on the SO-RB50cells was 0.11μmol/L, and ATRT was 12.84μmol/L. The cell growth curve in control group rose gradually along with the extended culture time, but after vincristine and ATRA treatment, the cell growth curve was smooth and steady. The cell increment was the least in drug combination group and its cell growth curve was the smoothest. There was significant difference in A450 48h and 72h after treatment (Fgrouping=77.316, P<0.001; Ftime=86.985, P<0.001). Compared with control group, A450 value in drug combination group, vincristine group, ATRA group was significant lower (P<0.001). Compared with control group, the G2/M phase cell proportion in vincristine group was significantly increased, while the G0/G1 phase cell proportion was significantly decreased; the G0/G1 phase cell proportion in ATRA group was significantly increased, while the S phase cell proportion was significantly decreased (FG0/G1=85.878, Fs=56.455, FG2/M=85.878, P<0.001). After 48h, there was significant difference in SO-RB50cell apoptosis rate among groups (F=11.312, P<0.05). The apoptosis rate in drug combination group was significantly higher than that of other groups (P<0.001). ATRA can increase the sensitivity of SO-RB50cells to vincristine. Vincristine combined with ATRA treatment can significantly increase the inhibiting effect on SO-RB50cells, which may be related with promoting cell apoptosis and involving in cell cycle control.