Tetrahydrocannabinol derivative ameliorates 5-FU mediated DNA damage propensity coupled with Vimentin suppression leading to autophagy induction

Abstract Anastasis cascade including induction of Epithelial to Mesenchymal Transition ( EMT), DNA repair, and stimulation of pro-survival mediators collectively exaggerate therapy resistance in cancer prognosis. The extensive implications of DNA-damaging agents are clinically proven futile for the rapid development of disease recurrence during treatment regime. In order to tackle this catastrophic event, recently, combinatorial approaches to prevent the pro-survival and pro-metastatic mediators responsible for incurring resistance to tumor cells are rapidly emerging. Herein we report a glycosidic derivative of Δ9-tetrahydrocannabinol (THC-9-OG) abrogates 5-Fluorouracil (5FU) induced EMT in colon cancer cells nullifying DNA repairing mechanism. Our in vitro and in vivo data strongly proclaims that THC-9-OG could not only abrogated 5FU mediated background EMT activation through stalling matrix gelatin degradation as well as murine 4T1 lung metastasis but also strongly diminished Rad51 DNA damage repairing mediator along with stimulation of γH2AX foci formation. The combinatorial treatment (5FU + THC-9-OG) in Apc knockout colorectal carcinoma model conferred remission of the crypt progenitor phenotype which was prominently identified in alone 5FU treatment. Mechanistically, we demonstrated that 5FU plus THC-9-OG significantly attenuated the major EMT inducer Vimentin via extensive ROS generation which simultaneously triggered autophagy induction via LC3B I-II conversion and p62 degradation in a p-ATM dependent manner. Additionally, Cannabinoid receptor CB1 was responsible for abrogation of Vimentin since we found increase in the expression of γH2AX and decrease in vimentin expression in CB1 agonist (ACEA) plus 5FU treated cells. Nutshell, our results unveil a new direction of Cannabinoid based combinatorial approach to control background EMT along with robust enhancing of DNA damage potential of sub-toxic concentration of 5FU resulting immense inhibition of distant metastasis coupled with triggering cell death in vitro and in vivo .