Syringic acid suppresses oral squamous cell carcinoma SCC131 cell proliferation via modulation of mitochondria-mediated apoptosis signaling pathways.

Apoptosis is an important process of cell death that controls the intrinsic and extrinsic pathways. Syringic acid (SRA)-a phenolic compound well-known in traditional Indian Ayurvedic medicine-has been reported to suppress cell proliferation of various cancer cells. Therefore, the current study aimed to investigate the inhibitory role of SRA on the proliferation of oral squamous cell carcinoma cells (SCC131) via reactive oxygen species (ROS) and induced mitochondria-mediated apoptosis. The study results showed that SRA (IC50 ) was able to induce apoptosis in SCC131 cells via increased ROS generation, alteration of mitochondrial membrane potential, nuclear fragmentation, apoptotic morphological differences, and DNA injury. Moreover, SRA inhibited proliferative markers such as proliferating cell nuclear antigen and cyclin D1 protein expression in SCC131 cells. A diminished level of B-cell lymphoma 2 (Bcl-2) and augmented level of Bcl-2-associated X protein (Bax) were considered as markers of apoptotic cell death. In addition, SRA was able to decrease Bcl-2 and increase mutant p53, caspase-9, Bax, and caspase-3 expression in SCC131 cells. Taken together, SRA succeeded in inhibiting SCC131 cell growth through the ROS and mitochondria-mediated apoptosis in oral cancer cells.