Abstract 1061: Advanced quantitative mass-spectrometry-based SILAC proteome profiling of Y-box binding protein-1 (YB-1) overexpressing breast cancer cells unravels proteins involved in metastasis

Abstract Metastasis is responsible for the majority of cancer related deaths and remains a global medical challenge in cancer treatment. The Y-box binding protein-1 (YB-1), a DNA and RNA binding protein, is known to regulate a plethora of fundamental cellular processes, including cell proliferation, chemoresistance and DNA repair. There is also cumulative evidence that YB-1 enhances breast cancer spread although the exact mechanism of YB-1-mediated metastasis is still not clear. Hence, we aim to determine the role of YB-1 overexpression in breast cancer progression. We first stably overexpressed YB-1 in non-aggressive MCF7 breast cancer cells (MCF7-YB-1) using a turboGFP tagged plasmid and performed phenotypic assays. We observed a significant increase in cell migration in MCF7-YB-1 in the Boyden chamber migration assay, which was substantiated by performing live imaging of the cells in a wound healing assay. Furthermore, a significant decrease in cell proliferation with G1 phase arrest was observed by the alamarBlue assay and flow cytometry analysis of propidium iodide staining, respectively for MCF7-YB-1 cells. We then performed a whole proteome analysis by stable isotope labelling with amino acids in cell culture (SILAC), a powerful proteomics platform. The whole proteome analysis identified 122 upregulated proteins and 120 downregulated proteins in the MCF-7-YB-1 cells. Bioinformatics analysis of the differentially regulated proteins using the Metacore software revealed the involvement of proteins that promote cell migration and invasion, such as those belonging to the S100 family which are enriched in the extracellular vesicles and exosome compartment, providing some mechanistic insights into the metastasis promoting role of YB-1. Taken together, our results showed that YB-1 could enhance the migratory potential of breast cancer cells, an important step in the metastatic cascade and therefore warrants a more in-depth study. Acknowledgement: Jia Pei Lim is a recipient of Ong Hin Tiang Scholarship in Cancer Research. This research was supported by Ministry of Education Grant (MOE2013-T2-1-129). Citation Format: Jia Pei Lim, Sunitha Nair, Sukanya Shyamasundar, Jayantha Gunaratne, Boon Huat Bay. Advanced quantitative mass-spectrometry-based SILAC proteome profiling of Y-box binding protein-1 (YB-1) overexpressing breast cancer cells unravels proteins involved in metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1061.