[Research progress on antitumor effect and molecular mechanism of capsaicin].

Capsaicin is a lipid-soluble vanillin alkaloid extracted from Capsicum plants in the Solanaceae family, which is the main active ingredient in capsicum, with multiple functions such as anti-inflammation, analgesia, cardiovascular expansion, and gastric mucosa protection. Recently, capsaicin has been confirmed as a potential antitumor compound. It can induce cell cycle arrest, inhibit cancer cell proliferation, metastasis, invasion, and angiogenesis, and promote apoptosis or autophagy in malignancy cell models and animal models of lung cancer, breast cancer, gastric cancer, and liver cancer. Meanwhile, capsaicin shows a synergistic antitumor effect when combined with other antitumor drugs such as sorafenib. Based on the recent literature on the antitumor effect of capsaicin, the present study analyzed the molecular mechanism of capsaicin in resisting tumors by inducing apoptosis and reviewed the effects of capsaicin in inducing tumor cell cycle arrest, inhibiting tumor cell proliferation, metastasis, and angiogenesis, and combating tumors with other drugs, thereby providing a theoretical basis for further research of capsaicin and its rational development and utilization.

The activation of adenosine monophosphate-activated protein kinase inhibits the migration of tongue squamous cell carcinoma cells by targeting Claudin-1 via epithelial-mesenchymal transition.

BACKGROUND: The role of Claudin-1 in tongue squamous cell carcinoma (TSCC) metastasis needs further clarification, particularly its impact on cell migration. Herein, our study aims to investigate the role of Claudin-1 in TSCC cell migration and its underlying mechanisms. METHODS: 36 TSCC tissue samples underwent immunohistochemical staining for Claudin-1. Western blotting and immunofluorescence analyses were conducted to evaluate Claudin-1 expression and distribution in TSCC cells. Claudin-1 knockdown cell lines were established using short hairpin RNA transfection. Migration effects were assessed through wound healing assays. Furthermore, the expression of EMT-associated molecules was measured via western blotting. RESULTS: Claudin-1 expression decreased as TSCC malignancy increased. Adenosine monophosphate-activated protein kinase (AMPK) activation led to increased Claudin-1 expression and membrane translocation, inhibiting TSCC cell migration and epithelial-mesenchymal transition (EMT). Conversely, Claudin-1 knockdown reversed these inhibitory effects on migration and EMT caused by AMPK activation. CONCLUSIONS: Our results indicated that AMPK activation suppresses TSCC cell migration by targeting Claudin-1 and EMT pathways.

Capsaicin exerts synergistic pro-apoptotic effects with cisplatin in TSCC through the calpain pathway via TRPV1.

Capsaicin (CAP) exerts significant anti-tumor effects on a variety of tumors, with low intrinsic toxicity. Cisplatin (DDP) is currently the first-line drug for the treatment of oral cancer; however, its clinical efficacy is impeded by chemoresistance and negligible side effects. Whether the combined use of CAP and DDP has a synergistic antitumor effect on tongue squamous cell carcinoma (TSCC) cells and its underlying mechanisms remains unclear. The present study revealed that CAP reduced the activity of TSCC cells in a dose- and time-dependent manner. We also observed changes in the mitochondrial functional structure of TSCC cells, along with the induction of mitochondrial apoptosis. Moreover, when CAP was combined with DDP, a synergistic cytotoxic effect on TSCC cells was observed, which had a significant impact on inducing apoptosis, inhibiting proliferation, and disrupting the mitochondrial membrane potential in TSCC cells compared to the single-drug treatment and control groups. These effects are associated with TRPV1, a high-affinity CAP receptor. The combined use of CAP and DDP can activate the TRPV1 receptor, resulting in intracellular Ca2+ overload and activation of the calpain pathway, ultimately leading to mitochondrial apoptosis. This potential mechanism was validated in TSCC xenograft models. In conclusion, our findings clearly demonstrate that CAP exerts synergistic pro-apoptotic effects with DDP in TSCC through the calpain pathway mediated by TRPV1. Thus, CAP can be considered an effective adjuvant drug for DDP in the treatment of TSCC.