MULTICELLULAR TUMOR SPHEROIDS (MCTS) AS AN IN VITRO MODEL FOR STUDYING SORAFENIB (SFB) RESISTANCE IN HEPATOCELLULAR CARCINOMA (HCC): EFFECT OF THE SIRTUINS 1/2 INHIBITOR EX-527 (EX) ON CELLULAR VIABILITY

PALMA, NICOLAS F; LIVORE, VERÓNICA INÉS; CHARES, LAURA G; FERRETTI, ANABELA CECILIA

Mar del Plata

Congreso; SAIC, SAI, SAFIS; 2022

SAIC, SAI, SAFIS

It is essential to count with more relevant preclinical models to study possible chemotherapy strategies for HCC. Tumors are 3D structures and their inner stromal cells contribute to cancer progression and chemoresistance (CR). MCTS composed of cancer and stroma cells provide reliable results in vitro since they mimic features of in vivo tumors. CR counteracts the efficacy of SFB, a first-line drug used for HCC, and better therapies are still missing. Sirtuins 1/2 promote cancer progression and CR. Aim: to study the effect of EX addition during SFB treatment in MCTS composed of Huh7 or SFB-resistant Huh7 (Huh7-SR) cells together with stromal cells. Methods: Huh7-SR cells were established after incubating Huh7 cells for 6 months with increasing doses of SFB. Resistance was evaluated in 2D cultures (MTT; Western Blot). MCTS of Huh7 or Huh7-SR, endothelial (EA.hy926) and hepatic stellate (LX-2) cells were obtained andtreated for 72 h with different doses of SFB, EX, SFB+EX or DMSO (control group). Cell viability was studied (acid phosphatase assay) and IC50 and combination index (CI) values were determined (CompuSyn). Results and discussion: Huh7-SR cells presented with a higher IC50 value for SFB (6.7µM*) compared to Huh7 cells (2.7µM) as well as more PCNA, cyclin D1, P-gp and MRP3 protein levels, confirming SFB resistance. SFB and EX reduced MCTS viability in a dose-dependent manner compared to the control group. Huh7-SR-formed MCTS were more resistance to SFB than Huh7-formed MCTS (IC50: 11µM* and 7µM, respectively). Different SFB+EX combinations decreased MCTS viability compared to the individual treatments (synergistic effect; CI