P22077 enhances the antitumor efficacy of Cisplatin and its mechanism

Activation of DNA damage repair pathways in tumor cells may reduce the treatment efficacy of platinum-based chemotherapeutic agents. Ubiquitin-specific protease 7 (USP7) is one of the deubiquitinating enzymes that can remove the ubiquitin from target proteins and protect substrate proteins from degradation. Although ubiquitin-specific protease 7(USP7) is highly expressed in cervical cancer tissues and plays an important role in DNA damage repair, the role of USP7 inhibition in the antitumor efficacy of cisplatin remains unknown. This study explored the effects and mechanisms of a USP7 inhibitor P22077 on the anti-cervical cancer efficacy of cisplatin. In in vitro studies, P22077 and cisplatin both significantly reduced HeLa cell proliferation and colony formation, and the combination produced preferable effects. In in vivo xenograft tumor model, P22077 and cisplatin both demonstrated significant antitumor efficacy. The drug combination produced greater antitumor activity than the individual drug alone. Cisplatin evoked DNA damage repair-related molecules and P22077 tended to prevent this change. The drug combination produced higher cell death rate than the individual drug alone. Collectively, These results suggest that the USP7 inhibitor P22077 alone has significant antitumor efficacy and also can enhance the antitumor effects of cisplatin. The USP7 inhibitor P22077 combined with cisplatin may be an effective treatment strategy for cervical cancer.