Esketamine Enhances the Chemosensitivity of Colorectal Adenocarcinoma Cells to 5-Fluorouracil via AMPK/mTOR/HMMR Signaling Pathway.

Background: The efficacy of standard 5-fluorouracil (5-FU) chemotherapy for colorectal cancer is limited by drug resistance and adverse effects, prompting research into esketamine, a potent ketamine variant with analgesic, antidepressant, and recently discovered anti-tumor properties, to determine if it can enhance 5-FU's chemosensitivity. This study investigates whether esketamine synergizes with 5-FU to enhance therapeutic efficacy in colorectal adenocarcinoma cell models. Methods: We performed functional assays to evaluate proliferation (CCK-8), migration (wound healing), invasion (Transwell), and apoptosis (flow cytometry) in colorectal adenocarcinoma cell lines treated with 5-FU alone or in combination with esketamine. Transcriptomic profiling was conducted using RNA sequencing, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was employed to identify critical molecular targets and signaling networks. Protein-level validation of key pathway components was performed via western blotting. Results: Combination therapy with esketamine and 5-FU synergistically inhibited cellular proliferation, migration, and invasion while significantly inducing apoptosis compared to monotherapy. Mechanistically, esketamine potentiated 5-FU-driven AMP-activated protein kinase (AMPK) phosphorylation, leading to inhibition of both mammalian target of rapamycin (mTOR) and hyaluronan-mediated motility receptor (HMMR). Conclusion: Esketamine enhances 5-FU chemosensitivity in colorectal adenocarcinoma by activating the AMPK/mTOR/HMMR signaling axis, thereby suppressing tumor progression and metastatic potential. These findings position esketamine as a potential adjunctive therapy for 5-FU-based regimens, offering the dual benefit of enhancing chemotherapeutic efficacy while addressing cancer-associated comorbidities including pain and depression.