Nanoencapsulation of Docetaxel Induces Concurrent Apoptosis and Necroptosis in Human Oral Cancer Cells (SCC-9) via TNF-α/RIP1/RIP3 Pathway

Human oral squamous cell carcinoma is the sixth most frequent malignant cancer, with an unacceptably high death rate that affects people's health. Albeit, there are several clinical approaches for diagnosing and treating oral cancer they are still far from ideal. We previously synthesised and characterised the docetaxel nanoformulation (PLGA-Dtx) and discovered that docetaxel nanoencapsulation may suppress oral cancer cells. The goal of this study was to figure out the mechanism involved in the suppression of oral cancer cell proliferation. We discovered that PLGA-Dtx inhibited SCC-9 cell growth considerably as compared to free docetaxel (Dtx), and that the viability of SCC-9 cells treated with PLGA-Dtx was decreased dose-dependently. MTT assay showed that PLGA-Dtx selectively inhibited the growth of PBMCs from oral cancer patients while sparing PBMCs from normal healthy controls. Further, flow cytometry analysis showed that PLGA-Dtx induced apoptosis and necroptosis in SCC-9 cells. G2/M cell cycle arrest has been confirmed on exposure of PLGA-Dtx for 24 h in SCC-9 cells. Interestingly, western blot investigation found that PLGA-Dtx increased the amounts of necroptic proteins and apoptosis-related proteins more efficiently than Dtx. Furthermore, PLGA-Dtx was more effective in terms of ROS generation, and mitochondrial membrane potential depletion. Pretreatment with necroptosis inhibitor Nec-1 efficiently reversed the ROS production and further recover MMP caused by PLGA-Dtx. Overall, this study revealed a mechanistic model of therapeutic response for PLGA-Dtx in SCC-9 cells and proposed its potency by inducing cell death via activation of concurrent apoptosis and necroptosis in SCC-9 cells via TNF-α/RIP1/RIP3 and caspase-dependent pathway.