Downregulation of MUTYH contributes to cisplatin‑resistance of esophageal squamous cell carcinoma cells by promoting Twist‑mediated EMT

Abstract

Acquired resistance to cisplatin (CDDP) in esophageal squamous cell carcinoma (ESCC) remains a major challenge in cancer therapy. Although progress has been made in identifying the mechanisms responsible for resistance to CDDP, the underlying mechanisms of resistance in ESCC are still not entirely understood. In the present study, a CDDP-resistant ESCC cell line EC109/CDDP was established by culturing parental EC109 cells in increasing concentrations of CDDP, and it was demonstrated that MutY homolog (MUTYH), a critical base excision repair gene, was significantly downregulated in the resistant EC109/CDDP cells compared with that noted in the parental cells. Ectopic expression of MUTYH by transient transfection of pcDNA3.1-MUTYH plasmid significantly enhanced the CDDP-mediated inhibitory effect on resistant cell proliferation and induction of apoptosis, while silencing of MUTYH by transiently transfecting MUTYH-targeted siRNA in parental cells led to decreased sensitivity to CDDP as demonstrated by MTT assay, suggesting the crucial involvement of MUTYH in CDDP resistance. Further experiments demonstrated that the CDDP-resistant cells went through epithelial-mesenchymal transition (EMT) driven by its master regulator Twist, and MUTYH overexpression significantly reduced the Twist expression level and reversed the phenotype of EMT as detected by western blot analysis and RT-qPCR assays, suggesting that downregulation of MUTYH contributed to the Twist-mediated EMT. Moreover, it was observed that the effect of MUTYH on Twist was also associated with its degradation in addition to transcription. MUTYH acted as a positive regulator of reactive oxygen species (ROS) that showed a low level in resistant cells via flow cytometry assay, as demonstrated by increased ROS production in response to MUTYH overexpression. Reduced ROS by using N-acetylcysteine led to a decrease in proteasome activity and sequentially inhibited the degradation of Twist. In conclusion, the present data demonstrated that EMT activation mediated by MUTYH downregulation, by both enhancing Twist transcription and blocking its degradation, is one of the mechanisms for acquisition of CDDP resistance in ESCC.

Low expression of PRDM5 predicts poor prognosis of esophageal squamous cell carcinoma

“…Studies have shown that patients with esophageal squamous cell carcinoma overexpressing TWIST1 had a poor prognosis, and the increase of TWIST1 can affected the invasion and migration ability of esophageal squamous cell carcinoma [30][31][32] . Relevant studies have shown that silence of TWIST1 in esophageal squamous cell carcinoma, cervical cancer and non-small cell lung cancer can enhance its drug sensitivity to cisplatin [33][34][35] , and studies have also shown that increased expression of TWIST1 can enhance the radiotherapy resistance of esophageal squamous cell carcinoma cells 36 . We suspect that this may be related to the longer overall survival of patients with high expression of PRDM5 that we have observed after adjuvant treatment after surgery.…”

Molecular mechanisms of chemo‐ and radiotherapy resistance and the potential implications for cancer treatment

“…The expression of pivotal BER gene MutY homolog (MUTYH) was found to be significantly downregulated in an esophageal cancer cell line with cisplatin resistance. CDDP‐resistant cells undergo EMT driven by the master regulator Twist, and MUTYH overexpression prominently reduces Twist expression levels and reverses the EMT phenotype 151 . In addition to affecting transcription, MUTYH is also related to the degradation of Twist 152 .…”

“…CDDP‐resistant cells undergo EMT driven by the master regulator Twist, and MUTYH overexpression prominently reduces Twist expression levels and reverses the EMT phenotype. 151 In addition to affecting transcription, MUTYH is also related to the degradation of Twist. 152 Overall, activation of EMT mediated by MUTYH downregulation is one of the mechanisms by which ESCC acquires CDDP resistance.…”

MicroRNAs and Their Influence on the ZEB Family: Mechanistic Aspects and Therapeutic Applications in Cancer Therapy

“…It is then processed by Drosha/Pasha and DICER1 proteins, which cleave the pri-miR to generate a mature miR. Next, the mature miR is incorporated in a complex to form miR-RNA-induced silencing complex assembly [ 66 , 67 , 68 , 69 , 70 ].…”