Abstract 2946: Effects of two novel quinoline-based non-nucleoside DNA methyltransferase inhibitors against bone sarcomas

Abstract

Abstract Introduction. Identification of new drugs against sarcomas still represents an urgent clinical need due to the rarity of these diseases. Aberrant DNA methylation of gene promoter regions is recognized to be highly involved in cancer and efforts have been made to synthesize non-nucleoside compounds that can effectively modulate gene expression, with bearable side effects. Two novel DNMT inhibitors (DNMTi), MC3353 and MC3343, were tested in Ewing sarcoma (EWS) and osteosarcoma (OS) cell lines to determine their effects on proliferation, apoptosis/necrosis induction, and cell differentiation. Methods and Results. We evaluated specificity on DNMTs inhibition of these compounds together with anticancer activities (cell growth inhibition, cell cycle perturbations, effects on programmed cell death) in a panel of EWS and OS cell lines. Cellular response to DNMTi treatment was assessed also at the molecular level by evaluation of key regulators of cell cycle and apoptosis. Effects on neural differentiation were assessed by β-III tubulin and heavy neurofilament modulation in Ewing sarcoma cells. Concurrently, effects on osteoblastic differentiation were carried out on Saos-2 OS cell line and evaluated by RT-PCR. Both inhibitors determined a significant inhibition of DNMTs activity. In vitro, MC3343 was found to slow cell proliferation by increasing the percentage of cells in G1 or G2/M phases, while MC3353 compound was unable to modulate cell cycle but induced an increase in cell death indicating a cytotoxic rather than a cytostatic effect. Modulation of key regulators of cell cycle and evaluation of PARP cleavage confirmed these results. Both DNMTi induced cell differentiation. In EWS, treatment significantly modulated the expression of neural markers (positivity to β-III tubulin; NF-H; neurite outgrowth). In OS cells, DNMTi increased both matrix mineralization and expression of genes specifically related to osteoblastogenesis. Conclusions. Non-nucleoside DNMTi may represent a possible new therapeutic approach to bone sarcoma. Grants from: Association for Cancer Research (IG2013_14049; to KS); 5 per mille contributions to Rizzoli Institute. FIRB RBFR10ZJQT, IIT-Sapienza Project, and FP7 Projects BLUEPRINT/282510 and A-ParaDDise/602080 to AM. CC is a recipient of a fellowship from the Associazione Onlus “il Pensatore: Matteo Amitrano” Citation Format: Maria Cristina Manara, Sergio Valente, Camilla Cristalli, Cristina Baricordi, Clemens Zwergel, Paola B Arimondo, Piero Picci, Antonello Mai, Katia Scotlandi. Effects of two novel quinoline-based non-nucleoside DNA methyltransferase inhibitors against bone sarcomas. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2946. doi:10.1158/1538-7445.AM2015-2946