Influence of Padina gymnospora on Apoptotic Proteins of Oral Cancer Cells-a Proteome-Wide Analysis

Abstract

Oral carcinoma is one of the most vicious forms of cancer with a very low survival rate, as its patients often respond poorly to conventional chemotherapy. Presently several researchers are attempting to pursue an alternative to this therapy using natural products. Considering the promising strategy and induction of apoptosis to target the cancer cells, we evaluated the influence of a seaweed Padina gymnospora (15 µg/ml and 20 µg/ml) in enhancing apoptosis of oral cancer cells (KB-CHR-8-5) after 24-h incubation. The morphological changes indicating apoptosis were primarily assessed using a light microscope after which the apoptosis was confirmed by performing AO/EB staining method. Subsequently, MMP and ROS levels in the cells were assessed using Rh 123 and DCFH-DA staining procedures, respectively. All the above tests confirmed the ability of P. gymnospora to accelerate apoptosis in the oral cancer cells. As a next step, wide proteome analysis was performed where the proteins from P. gymnospora-treated cells were separated using the 2D electrophoresis technique and compared with that of control cells to isolate the differentially expressed proteins. This procedure resulted in the isolation of 10 proteins which were identified using MALDI-TOF/TOF MS, which established that most of the isolated proteins were part of the apoptotic process of the cell. The proteins identified are part of huge and complex pathways where it gets linked with many more genes which are also associated with apoptosis. Bioinformatics of these identified proteins was analyzed using STRING and PANTHER databases. These proteins contribute to cell apoptosis by affecting various functions, biological processes, and the synthesis of cellular components. PANTHER also demonstrated that these proteins belong to the classes of proteins that take part in several vital pathways of the cell among which the apoptotic pathway is the predominant one.

Keywords: 2D electrophoresis; Apoptosis; MALDI-TOF/TOF MS; Oral cancer; PANTHER; Padina gymnospora; STRING.