LncRNA TMPO-AS1 aggravates the cisplatin resistance in cervical cancer via miR-140-5p/DNMT1 axis-mediated DNA methylation of KLK10
Cisplatin resistance severely limits the efficacy of chemotherapy for cervical cancer (CC), and its molecular mechanisms remain incompletely understood. While epigenetic alterations such as DNA methylation are recognized as important contributors, the upstream regulatory networks, particularly the role of long non-coding RNAs (lncRNAs), are still unclear. This study aimed to explore novel mechanisms influencing cisplatin resistance in cervical cancer. Cisplatin-resistant CC cells (HeLa and SiHa) were established. A comprehensive approach employing mRNA and lncRNA microarrays, RT-qPCR, methylation-specific PCR (MSP-PCR), chromatin immunoprecipitation, luciferase reporter assays, RNA pull-down, RNA immunoprecipitation, cellular functional assays, and a mouse subcutaneous xenograft tumor model was utilized. The study found that Kallikrein 10 (KLK10) expression was significantly downregulated in cisplatin-resistant CC cells due to promoter hypermethylation mediated by DNA methyltransferase 1 (DNMT1). LncRNA microarray analysis revealed that TMPO-AS1 was the most significantly upregulated lncRNA in resistant cells. Functional assays confirmed that TMPO-AS1 promoted cisplatin resistance, proliferation, migration, and invasion of CC cells. Mechanistically, TMPO-AS1 acted as a competitive endogenous RNA (ceRNA) by sponging miR-140-5p, thereby relieving its inhibitory effect on DNMT1 mRNA, upregulating DNMT1 expression, enhancing KLK10 promoter methylation, and leading to its silencing. In vivo experiments further demonstrated that silencing TMPO-AS1 inhibited tumor growth. This study unveils a novel TMPO-AS1/miR-140-5p/DNMT1/KLK10 regulatory axis that plays a critical role in cisplatin resistance in CC, providing a potential therapeutic target for overcoming chemoresistance.