THE ROLE OF AMPK-MEDIATED AUTOPHAGY IN COLON CANCER AND ITS THERAPEUTIC IMPLICATION IN PHOTODYNAMIC THERAPY WITH METHYL-AMINOLEVULINATE

COGNO I.S.; PLACCI ARDITI M.; IBARRA L.E.

Mar del Plata

Congreso; REUNIÓN DE SOCIEDADES DE BIOCIENCIAS 2020; 2020

SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA

Colorectal cancer (CRC) is the second leading cause of cancer death. The increased resistance of CRC to conventional therapies led to the need to seek new treatments such as photodynamic therapy (PDT). However, autophagy has been recently linked to the resistance of different antitumor treatments including PDT. Although autophagy is considered mainly as a cell survival mechanism, autophagy-mediated cell death has also been described evidencing the dual role of this process whose effects on therapeutic resistance are not yet fully elucidated. The increase in adenosine monophosphate (AMP) levels in cells will activate the AMP-dependent kinase (AMPK), who induce autophagy through the inhibition of the mTOR complex. Based on the above, we propose to characterize the mechanisms that govern autophagy in CRC through the AMPK-induced pathway and its implication in the therapeutic response to PDT. For this, we used the GEPIA and Human Protein Atlas database to study the relevance of AMPK and its correlation with the main modulators of autophagy in CRC. We also established two autophagy induction systems using SW480 CCR cells. For the AMPK-dependent pathway, cells were incubated in phosphate buffer saline (PBS 1X, 15min - 2 h) and for the AMPK-independent pathway, Compound C (10-20 μM, 18 and 8 h) in growth medium was implemented. It was shown that the induction of autophagy, by both conditions, produces a decrease in cell viability (MTT) in CRC cells (p value < 0.0001) over time where apoptosis is the main mechanism of cell death (determined by an Annexin V/Propidium iodide assay 24 hours post-autophagy induction measured by flow cytometry). Lastly, it was shown that cells with active autophagy (dependent and independent of AMPK) does not affect the cell viability (MTT) of CRC cells (p value = ns) treated with PDT (1.8 J/cm2; Me-ALA 0.5 mM); which suggests that neoadjuvant treatments, which induce autophagy through these pathways, could be beneficial for the success of PDT.