PO-190 In silico and in vitro screening of polyphenolic compounds for their mTOR modulatory capacity

Introduction The phosphoinositide 3-kinase (PI3Ks)/protein kinase B (PKB or AKT)/mammalian target of rapamycin (mTOR) signalling pathway is essential for tumorigenesis and metastasis in many types of human tumours and some tumour cells owe their hyperproliferative capacity to the overactivation of this pathway, in response to mutations that abolish some repressing genes. Therefore, the inhibition of mTOR and the subsequent activation of autophagy has been postulated as a therapeutic target in certain types of tumours. Therefore, the control of the route governed by mTOR can be a therapeutic target, both positively and negatively, depending on the type of tumour. It is economically unfeasible to analyse libraries of millions of bioactive compounds in vitro. For this reason, in recent years in silico methodologies are being used since reduce the size of these libraries to an affordable number of compounds that can be tested in vitro. In this work we studied the modulatory effect on mTOR in the highly invasive HCT-116 colon cancer model of 11 compounds of plant origin, that were selected an in silico screening. Material and methods Citotoxicity assay Cell viability was measured through the MTT assay and the dose-response curves were used to calculate the optimal concentrations of each compound to study its activity upon mTOR. In silico screening A library of compounds, previously selected with ADMET criteria, were tested in silico with molecular docking experiments, using AutoDock/vina. Protein expression The expression of mTOR and activation (phosphorylated form) were measured by western blot. β-actin was used as a loading control and PARP as a viability control. Results and discussions The results of IBMC-C, IBMC-F, IBMC-H and IBMC-J compounds show a decrease similar to that caused by rapamycin, that is a mTOR inhibitor, immunosuppressant and kinase inhibitor. Conclusion Compounds IBMC-C, IBMC-F, IBMC-H and IBMC-J may have potential to inhibit the proliferation of highly invasive colon cancer cells. Their mechanism of action in relation to the inhibition of mTOR and autophagy activation may deserve further studies.