ALYREF-Mediated Regulation of TBL1XR1 and KMT2E Synergistically Upregulates APOC1, Contributing to Oxaliplatin Resistance in Esophageal Cancer.

Abstract

Purpose: Esophageal cancer (EC) is a rapidly progressing malignancy characterized by a low survival rate and limited treatment success, largely due to late-stage detection, frequent recurrence, and a high propensity for metastasis, despite ongoing advances in therapeutic strategies. While oxaliplatin (L-OHP) is a potent chemotherapeutic agent that induces apoptosis in EC cells, its effectiveness is significantly hindered by the development of resistance.

Materials and methods: The assessment of gene and protein expression was conducted through a combination of RT-qPCR, Western blot, and IHC staining. Cell viability was assessed using the CCK-8 assay. The interactions among ALYREF, TBL1XR1, KMT2E, and APOC1 were investigated through RIP, ChIP, ChIP-reChIP, RNA pulldown, and dual-luciferase assays. An in vivo mouse model of EC was established.

Results: Expression levels of both APOC1 and ALYREF were elevated in L-OHP-resistant EC tissues and cell lines, and their silencing enhanced sensitivity to L-OHP. TBL1XR1 and KMT2E synergistically upregulated APOC1 expression. Moreover, ALYREF recognized the m5C sites on TBL1XR1 and KMT2E mRNAs, stabilizing these transcripts and promoting APOC1 expression. The regulatory role of these interactions was further validated in vivo.

Conclusion: This study demonstrated that ALYREF interacted with the m5C sites on TBL1XR1 and KMT2E mRNAs, enhancing their stability and leading to increased transcription of APOC1, which in turn contributed to L-OHP resistance in EC. These findings suggest that targeting APOC1 could be a promising strategy for overcoming L-OHP resistance in EC.