Osteosarcoma metastatic cells impact in the induction of chemoresistant phenotype in fibroblast: impact on tumoral microenvironment and treatment response

VALENZUELA ALVAREZ, MATIAS; RIZZO, MATIAS; AUZMENDI, JERONIMO; LAZAROWSKI, ALBERTO; BOLONTRADE, MARCELA F.

Congreso; LXVI Reunión Anual SAIC, Sociedad Argentina de Investigación Clínica; 2021

Tumor associated fibroblast (TAF) have been implicated in almost every aspect of tumoral biology. Of relevance TAF could be modulating response to treatment and overall microenvironment development. Given that Osteosarcoma (OS) have the same 5-year survival rate for metastatic and treatment resistant patients since 1970 ́s, we dediced to investigate the role of TAF in OS primary and metastatic niches. Aim: Evaluate TAF and human OS cell lines interaction in primary and pulmonary metastatic environments. To analyze if metastatic OS cell line has a higher inducing power than non-metastatic OS cell line analyzing the expression of different ABC transporters im-plicated in chemoresistance and the ability to exclude doxorubicin and rhodamine. Methods: The expression of ABC transporters was analyzed by RT-qPCR on conditioned fibroblast. Rhodamine 123 exclution assay was used to determine the activity of P-glycoprotein (P-gp) mediated transport and doxorubicin (DOX) exclution was performed to analysis the overall ABC-related chemoresistant capacity. To evaluate the interaction of fibroblast with metastatic (LM7) and non-metastatic (SAOS2) OS human cells hetero – spheroid formation assays were performed. Results: LM7 conditioned medium (CM) induced an overall upregulation of ABC transporters in comparison with SAOS2 CM. Conditioned fibroblast with LM7 CM showed lower levels of intracellular DOX and Rhodomine in comparison with SAOS2 CM fibroblast. Mixed spheroid compose of fibroblast ans OS cell lines display a lower area and more compact than single type aggregates. OS has not changed the 5-year rate survival for metastatic patients since the 70’, so the need to understand aspects of OS metastatic biology and chemoresistance could be helpful to develop new treat-ments to this group. Knowing aspects of the associated stroma and in particular TAF, could allow the development of new therapeutic possibilities targeting the tumoral associated stroma.