Evaluation of Anti Cancer Activity of selected medicinal plant extracts on the Squamous Cell Carcinoma cell Lines

Abstract

ABSTRACT newlineAccording to World Health Organization (WHO), cancer is a leading cause of death worldwide and accounted for 7.6 million deaths (around 13% of all deaths) in 2008 and deaths are projected to rise over 11 million in 2030. Since epithelial cells cover the skin, line the respiratory and alimentary tracts, and metabolize ingested carcinogens, it is not surprising that over 90% of cancers occur in epithelia. Therefore, in the present study we are dealing with two major epidermoid cancers i.e. squamous cell carcinoma of skin and oral cancer, which belong to the same cell type the epithelia. Several approaches are implicated to treat cancer; one of the major effective modality against most of the cancers is chemotherapy but due to drug resistance and lack of specificity, successful outcome in most cases is limited; a major problem that is further augmented by subsequent relapses. Thus, major thrust in cancer treatment is on search for better, safer and cancer-cell- targeted drug options of natural origin, which may enhance the effectual cancer treatment. In the present study, we endeavored to evaluate selected medicinal plants newlineSemecarpus anacardium (SA) and Cissus quadrangularis (CQ) for their effects against signaling events associated with cancer employing Skin epidermoid carcinoma cells (A431) and Oral epidermoid carcinoma cells (KB), simultaneously comparing their effects on normal keratinocyte cells (HaCaT) with a positive control 5-Flourouracil. The findings of the present study suggested selective targeted-cancer-cell based anticancer potential of methanolic extract of nut of SA and ethanolic extract of stem of CQ. The SA extract selectively elevated levels of reactive oxygen species (ROS), resulted in loss of mitochondrial membrane potential (MMP), induced apoptosis, and led to G1 phase cell cycle arrest in cancer cells. The SA extract also upregulated p53 and Casp-3 by several folds and led to seven-fold downregulation of Bcl-2 expression. The major bioactive compounds of SA nut methanolic newlineextract as detected by GC-MS analysis were docked with mutant and wild type p53 exhibited higher binding affinity towards mutant p53 as compared to wild type p53. The CQ extract also led to increased levels of ROS, loss of MMP, induction of apoptosis and G1 phase cell cycle arrest in cancer cells as compared to normal cells (HaCaT). The effect of CQ extract on proteins associated with apoptosis i.e. p53, Casp-3 and Bcl-2 was evaluated by western blotting. The data obtained for protein profiling revealed that CQ extract down-regulated Bcl-2 to a higher extent i.e. upto nine fold as compared to up-regulation of p53 and Casp-3. The in silico analysis also showed that the active constituents found in CQ extract, sequester Bcl-2 with higher affinity as compared to p53, which may be the reason for induction of selective growth arrest and apoptosis in KB and A431 cells as compared to normal cells (HaCaT). Apart from this, the spheroid HeLa in vitro model was generated for analyzing the CQ extract response on the growth of HeLa tumoroid. CQ extract also significantly inhibits the growth of tumoroid and finally leads to cell death as revealed by phase contrast microscopy. newlineTherefore, it can be concluded from the present findings that the extracts from selected parts of SA and CQ exhibit targeted and selective anticancer activity via induction of apoptotic pathway. newline newline