Abstract 5471: Ribosome heterogeneity and RNA polI inhibition in osteosarcoma heterogeneity

Abstract

Abstract Osteosarcoma is the most common primary bone tumour in adolescents and young adults, with an incidence rate of 3.8 per million. These tumors affect the long bones of the body such as femur. Current standard therapy includes tumour resection associated with multi-drug chemotherapy. The 5-year survival rate can reach 65% but is significantly reduced to 30% when pulmonary metastases are detected at the time of diagnosis. As this rate has not improved in the last 50 years, it is necessary to identify new therapeutic strategies. Inhibition of ribosomal biogenesis is one of the strategies developed in many cancer studies. This can be obtained by inhibition of RNA pol I, and in particular by BMH-21. The objective of this study was to analyze the complexity and heterogeneity of osteosarcomas through the ribosomal spectrum. The effect of BMH-1 on survival was also studied in osteosarcoma cell lines. The data obtained showed that there was no difference in ribosome protein composition in the “core” ribosome in different osteosarcoma cell lines. In addition, BMH-21 decreased cell viability in all osteosarcoma and chemoresistant cell lines. However, any activation of the apoptotic pathway by caspases was detected, nor any impact on the formation of new colonies after treatment with BMH-21. These results suggest a rather cytostatic mechanism. Moreover, a G0/G1 arrest in cell cycle was shown for U2OS cells. Finally, BMH-21 does not appear to have any impact on migration in HOS and U2OS cells. The different molecular mechanisms involved in the regulation of proliferation need to be further investigated. Citation Format: Marc Baud'huin, Elvina Colleville, Rose Anne Thepault, Emilien Orgebin, Francois Lamoureux, Benjamin Ory. Ribosome heterogeneity and RNA polI inhibition in osteosarcoma heterogeneity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5471.