Kutkoside-an iridoid glycoside, exerts anti-proliferative effects in drug-resistant human oral carcinoma cells by targeting PI3K/AKT signalling pathway, inducing apoptosis and suppressing cell migration and invasion.

ABSTRACT

PURPOSE: The main purpose of the current research work was to investigate the anticancer potential of Kutkoside -a naturally occurring iridoid glycoside, against drug-resistant human oral carcinoma cells along with evaluating its effects on PI3K/AKT signalling pathway, cellular apoptosis, cell migration and cell invasion. METHODS: Cell viability was assessed by using MTT colorimetric assay, while effects on cellular apoptosis were evaluated by acridine orange (AO)/ethidium bromide (EB) as well as by using flow cytometry employing annexin V-FITC. Effects on cell migration and cell invasion were evaluated by in vitro wound healing assay and transwell Matrigel assay. Effects on PI3K/AKT signalling pathway were evaluated by western blot method. RESULTS: Kutkoside led to significant and dose-dependent inhibition of HSC-2 human oral cancer cells using doses of 0, 1.25, 2.5, 5, 10, 20, 40, 80 and 160 µM. Fluorescence microscopy revealed that on increasing the dose of kutkoside, the number of both apoptotic and necrotic cells increased, showing that Kutkoside induces apoptotic cell death in HSC-2 oral cancer cell line in dose-dependent manner. Flow cytometry indicated that the percentage of apoptotic cells at different dose exposures of Kutkoside, namely 0, 8, 16 and 32 µM was 4.9%, 12.18%, 22.18% and 34.10%, respectively. Kutkoside treatment also led to cell migration inhibition and cell invasion inhibition. This molecule upregulated the expression of AKT and PI3K, simultaneously downregulating the expressions of p-AKT and p-PI3K in a dose-dependent manner. CONCLUSION: Kutkoside shows potential anticancer and pro-apoptotic effects in HSC-2 oral carcinoma cells and as such may be developed as a possible anticancer agent provided further studies are performed.