The impact of SEC23A on 5-FU chemotherapy sensitivity and its involvement in endoplasmic reticulum stress-induced apoptosis in colorectal cancer

Colorectal cancer (CRC) represents a significant global health burden, with chemotherapy resistance representing a significant challenge to effective treatment. SEC23A, a core component of the COPII vesicle trafficking system, is of critical importance with regard to protein transport and cellular homeostasis. Nevertheless, its function in CRC progression and chemoresistance remains uncertain. The present study investigates the correlation between SEC23A expression and sensitivity to 5-fluorouracil (5-FU), a widely used chemotherapeutic agent, with particular emphasis on ER stress-induced apoptosis. A bioinformatic analysis was conducted to evaluate SEC23A expression in CRC and its association with patient prognosis. Chemotherapy sensitivity was predicted using GDSC data and validated experimentally using CRC cell lines with manipulated SEC23A expression. In order to explore the role of SEC23A in acquired drug resistance, patient-derived xenograft (PDX) models and 5-FU-resistant cell lines were employed. Apoptosis assays, cell cycle analysis, and ER stress modulation experiments were performed to elucidate the underlying mechanisms. SEC23A expression was significantly reduced in CRC samples compared to normal tissues. This reduction was linked to a poorer prognosis, including both overall and disease-specific survival. A correlation was observed between low SEC23A expression and increased resistance to 5-FU, as evidenced by both bioinformatic predictions and in vitro experiments. In PDX models, metastatic lesions exhibited decreased SEC23A expression following 5-FU treatment in comparison to primary tumors. Overexpression of SEC23A in 5-FU-resistant cell lines restored sensitivity to the drug and increased apoptosis. Bioinformatic and experimental analyses revealed a robust correlation between SEC23A and ER stress-related apoptotic pathways. Elevated expression of SEC23A was observed to facilitate the accumulation of misfolded proteins in response to 5-FU treatment, which in turn resulted in increased ER stress and apoptosis. SEC23A plays a crucial role in modulating the sensitivity of CRC cells to 5-FU by regulating ER stress-induced apoptosis. Its downregulation contributes to chemoresistance, indicating that SEC23A may serve as a prognostic marker and therapeutic target in CRC. Strategies aimed at upregulating SEC23A or enhancing ER stress may provide new avenues for overcoming chemoresistance and improving treatment outcomes for CRC patients.