PDK1 regulates the progression of esophageal squamous cell carcinoma through metabolic reprogramming.

Esophageal squamous cell carcinoma (ESCC) is one of the deadliest human malignancies characterized by late-stage diagnosis, drug resistance, and poor prognosis. Pyruvate dehydrogenase kinase 1 (PDK1) plays an important role in regulating the metabolic reprogramming of cancer cells. However, its expression, function, and regulatory mechanisms of PDK1 in ESCC have not been reported. In this study, we found that PDK1 silence and dichloroacetic acid (DCA) significantly inhibited the growth of ESCC cells and induced cell apoptosis. Interestingly, PDK1 is a direct target of miR-6516-5p, and miR-6516-5p/PDK1 axis suppressed the growth of ESCC cell by inhibiting glycolysis. Moreover, DCA and cisplatin (cis-diammine-dichloroplatinum, DDP) synergistically inhibited the progression and glycolysis ability of ESCC cells both in vitro and in vivo by increasing oxidative stress via the inhibition of the Keap1/Nrf2 signaling pathway. And, Tert-butylhydroquinone (TBHQ), a specific activator of the Keap1/Nrf2 signaling, could diminish the synergic antitumor effects of DCA and DDP on ESCC cells. Collectively, our findings indicate that PDK1 may regulate the progression of ESCC by metabolic reprogramming, which provides new strategy for the treatment of ESCC.

CCT4 knockdown enhances the sensitivity of cisplatin by inhibiting glycolysis in human esophageal squamous cell carcinomas.

Esophageal squamous cell carcinoma (ESCC) is a common human malignancy characterized by late-stage diagnosis, metastasis, and poor prognosis. Cisplatin (DDP)-based chemotherapy has been the most predominant treatment for patients with ESCC. However, the high rate of DDP resistance and toxicity seriously hinder its clinical application. Then, the optimized strategy and mechanisms for ESCC to enhance DDP sensitivity are in great demand. Accumulating evidence have shown that chaperone proteins are closely related to the tumorigenesis and drug resistance of cancers. Chaperonin containing TCP1 complex 4 (CCT4) is a recent identified member of the family. However, its expression and function in ESCC have not been well illustrated. In this study, we found that CCT4 was highly expressed in human ESCC tissues and cell lines, and closely related to the poor prognosis. Moreover, CCT4 silence raised oxidative stress and inhibited glycolysis of ESCC cells, which significantly inhibited cell proliferation and migration, promoted apoptosis and caused cell cycle arrest in ESCC cells. Interestingly, CCT4 knockdown enhanced the sensitivity of KYSE150 cells to DDP by regulating AMPK/AKT/Nrf2 signaling pathway and inhibiting glycolysis ability. Taken together, our results indicate that targeting CCT4 may be a therapeutic target in ESCC patients, which provides a theoretical basis to enhance the sensitivity of DDP in ESCC.