Ubiquitin-like protein D enhances the sensitivity of MDA-MB-231 cells to cisplatin via the Bcl-2/Bax/caspase-3 pathway in triple-negative breast cancer

Objective: To study the effects of ubiquitin-like protein D (UBD) expression on the sensitivity of cisplatin to human triple negative breast cancer MDA-MB-231 cells. Methods: Thirty-five cases of triple negative breast cancer patients who were treated by chemotherapy with cisplatin and surgery in our hospital were divided into a CR group and PR group according to postoperative pathological diagnosis. Expression of UBD was compared before chemotherapy and UBD over expression and silenced expression were generated in MDA-MB-231 cells. The expression of UBD, Bax, Bcl-2, and caspase-3 were compared and the IC50 to cisplatin was determined in different MDA-MB-231 cells. Results: The positive cell ratio of UBD and Bcl-2 was (20.8+ 7.9%) and (41.3+ 12.9%) respectively in tumor tissue of the CR group, which was significantly lower than the PR group (68.3+ 12.4%) and (77.8+ 20.4%) (P< 0.05). The positive cell ratio of Bax and activated caspase-3 was (56.9+ 15.7%) and (67.3+ 21.4%) respectively in tumor tissue of the CR group, which was significantly higher than the PR group that was (30.6+ 11.5%) and (36.6+ 10.1%) (P< 0.05). The IC50 of cisplatin in 231-Silence, MDA-MB-231, and 231-Over was (19.82+ 1.08) mu mol/L, (35.69+ 1.21) mu mol/L and (67.79+ 1.54) mu mol/L respectively. The relative expression of Bcl-2 in MDA-MB-231 cells was (0.66+ 0.17), which was significantly higher than 231-Silence (0.075+ 0.05) (P< 0.05), and significantly lower than 231-Over (1.05+ 0.22) (P< 0.05). The relative expression of Bax and activated caspase-3 in MDA-MB-231 cells was (0.44+ 0.10) and (0.70+ 0.19) respectively, which was significantly lower than 231-Silence [(1.08+ 0.24) and (1.28+ 0.31)] (P< 0.05) and significantly higher than 231-Over [(0.17+ 0.09) and (0.36+ 0.12)] (P< 0.05). Conclusion: The high expression of UBD enhanced the resistance of cisplatin to MDA-MB-231, and the mechanism may be related to the high expression of UBD reduced Bax and caspase-3 gene expression and increased Bcl-2 gene expression.