Role of Indian Mustard Honey in Inhibiting Colon Cancer Stem Cells and 5-Fluorouracil Resistant Colorectal Adenocarcinoma by Acting on Lgr5

Abstract

Colon cancer is the third most prevalent cause of cancer related deaths across the globe. The origin of Colorectal cancer lies in the “clonogenic core”, i.e., a small population of highly proliferative Cancer stem cells. Colon cancer stem cells (CSC) predominantly express Lgr5 which correlates to their stemness and tumorigenic potential. Association of Lgr5 with its ligand R-spondin triggers the Wnt signaling pathway to upregulate proliferation and metastasis of Colon cancer. Chemotherapy against colon cancer has been partly successful, however, associated toxicity and drug resistance have become the primary concern regarding survival of patients. Alternative medicine has been widely employed in cancer treatment since past two decades due to its beneficial effects on health, sustainability and different bioactive properties. Honey is a popular form of alternative medicine which possesses antioxidant, anti inflammatory and anticancer properties owing to its constituents, e.g., flavonoids and polyphenols. In this study, we aim to circumvent drug resistance in colon cancer by combining traditional anticancer drug 5-Fluorouracil (5-FU) and Indian Mustard Honey in 5-FU resistant Colon cancer. To develop drug resistant Colon cancer model, COLO-205 cells were subjected to suboptimal doses of 5-FU. Lgr5 was presumed to be highly overexpressed in this model which was conclusive of the role of Lgr5 in rendering drug resistance. The expression profiles of different EMT markers, e.g., E-cadherin, N-cadherin, Vimentin and drug efflux transporters, e.g., ABCB1, ABCC1 and ABCG2 were evaluated before and after treatment of Indian Mustard Honey, using Western blotting and real time PCR. A decrease in expression of the aforementioned genes was expected after treatment with Indian Mustard Honey, taking a cue from its anticancer properties from existing literature. Additionally, Lgr5 expression was also expected to decrease following honey treatment. Decreased expression of CSC marker, Mesenchymal markers as well as drug efflux transporters incurred by Indian Mustard honey is hypothesized to result in increased efficacy of 5-FU based chemotherapy. Therefore, the present study aims to alleviate the current scenario of 5-FU resistance in Colorectal cancer with the help of Indian Mustard honey.