Effects of Vitamin K3 Combined with UVB on the Proliferation and Apoptosis of Cutaneous Squamous Cell Carcinoma A431 Cells

PURPOSE: Cutaneous squamous cell carcinoma (cSCC) is the second most common form of skin cancer and its incidence continues to rise yearly. Photodynamic therapy (PDT) is a non-invasive form of cancer therapy, which utilizes the combined action of a photosensitizer, light, and oxygen molecules to selectively cause cellular damage to tumor cells. Vitamin K3 (VitK3) has been shown to induce apoptosis and inhibit the growth of tumor cells in humans. The purpose of this study was to determine the effect of VitK3 and ultraviolet radiation B (UVB) on oxidative damage, proliferation and apoptosis of A431 cells. METHODS: CCK-8 assay was used to detect cell proliferation; Hoechst staining, TUNEL assay and flow cytometry analysis were used to detect apoptosis. Western Blot was perfomed to measure the expression of apoptosis-related proteins. Flow cytometry analysis was employed to detect the reactive oxygen species (ROS) levels and mitochondrial membrane potential. Finally, the role of VitK3 in combination with UVB on the proliferation and apoptosis of A431 cells was investigated using mice xenograft models. RESULTS: We found that the co-treatment of VitK3 combined with UVB more significantly inhibited the growth and proliferation of A431 cells than either VitK3 or UVB alone. Hoechst 33258 staining and flow cytometry analysis revealed that apoptosis was more pronounced in the VitK3-UVB group compared to the VitK3 and UVB groups. Moreover, flow cytometry analysis showed that ROS and the depolarization of the mitochondrial membrane potential were higher in all the co-treatment groups compared to the control, VitK3, and UVB groups. The VitK3-UVB group exhibited a significantly lower tumor growth rate in mouse xenograft models. CONCLUSION: This study reveals that VitK3 combined with UVB inhibits the growth and induces apoptosis of A431 cells in vitro and suppresses tumor growth and promotes apoptosis of cSCC in vivo.