IAP-1 promoted cisplatin resistance in nasopharyngeal carcinoma via inhibition of caspase-3-mediated apoptosis.

Recurrent/metastatic nasopharyngeal carcinoma (NPC) is known for having a poor prognosis due to its unfavorable response to chemoradiotherapy. However, the specific processes involved remain poorly understood. This study focused on the cisplatin-resistance mechanism in NPC to help understand the occurrence of advanced NPC and aims to explore the potential therapeutic target for cisplatin-resistant NPC. Two cisplatin-resistant NPC cell lines, HNE-1/DDP and CNE-2/DDP, were established and the differentially expressed genes (DEGs) between parental and cisplatin-resistance cell lines, filtering from high-throughput sequencing results, were analyzed. Next, the effects of IAP-1 on cisplatin-resistant nasopharyngeal cancer cell proliferation, apoptosis, drug resistance and associated cell signaling were evaluated in vitro and in vitro. From our bioinformatic results, more than 15,000 differentially expressed genes (DEGs) were found between parental and resistant cell lines. Nine related DEGs were found in the classic platinum resistance pathway, three of which (ATM, IAP-1, and IAP-2) also appeared in the top five differentially expressed pathways, with elevated IAP-1 showing the highest fold change. Further studies revealed that high IAP-1 expression can lead to an increased cisplatin inhibitory concentration and apoptosis inhibition. IAP-1 silencing can induce upregulation of the caspase-3 and enhance the antiproliferation and proapoptotic effects of cisplatin. Clinical data also showed that IAP-1 overexpression was associated with a worse survival status. In summary, in vitro and in vivo experiments demonstrated that IAP-1 plays a vital role in cisplatin resistance by regulating caspase induced apoptosis and serve as a potential novel therapeutic target and a prognostic indicator for advanced NPC. AJCR