RESUMEN
Objective: To investigate the influence of maximum-tolerated dose chemotherapy with cisplatin (MTD-DDP) and low-dose metronomic chemotherapy with DDP (LDM-DDP) on human ovarian carcinoma xenograft tumor in nude mice and the expression of aldehyde dehydrogenase 1 (ALDH1) in xenograft tumor. Methods: Murine subcutaneous xenograft tumors of human epithelial ovarian cancer SKOV3 cells were established in nude mice and treated with MTD-DDP and LDM-DDP, respectively. The growth of xenograft tumor was observed. The xenograft tumor primary cells were established. ALDH1-positive cells were obtained by fluorescence-activated cell sorting. The abilities of colony formation and tumorigenicity of ALDH1-positive cells in vitro and in vivo were detected by colony formation assay and tumor formation in nude mice, respectively. The expression levels of Ki-67, breast cancer resistant protein (BCRP) and CD133 in ALDH1-positive cells were detected by Western blotting. Results: The growth of xenograft tumor in nude mice was inhibited by MTD-DDP and LDMDDP, and this inhibition effect was significant in LDM-DDP group (P < 0.001). The proportion of ALDH1-positive cells in xenograft tumor primary cells was lower in MTD-DDP group and higher in LDM-DDP group as compared with that in the control group (0.9% NaCl solution) (both P < 0.001). The abilities of colony formation and tumorigenicity of ALDH1-positive cells were higher than those of ALDH1-negative cells (both P < 0.001). The expression level of Ki-67 was lower but the expression levels of BCRP and CD133 were higher in ALDH1-positive cells than those in ALDH1-negative cells (all P < 0.001). Conclusion: LDM-DDP can effectively inhibit the growth of human ovarian carcinoma xenograft tumors in nude mice and reduce the proportion of ALDH1-positive cells.