Non-POU Domain-Containing Octomer-Binding (NONO) protein expression and stability promotes the tumorigenicity and activation of Akt/MAPK/β-catenin pathways in human breast cancer cell Running title: NONO promotes the tumorigenicity of breast cancer

Breast cancer is one of the most common cancers with high mortality, highlighting the vital need to identify new therapeutic targets. Here we report that Non-POU Domain-Containing Octamer-Binding (NONO) Protein is overexpressed in breast cancers and validated the interaction of WW domain of PIN1 with c-terminal Threonine-Proline (thr-pro) motifs of NONO. The interaction of NONO with PIN1 enhances NONO’s stability by inhibiting its proteasomal degradation, and this identifies PIN1 as a positive regulator of NONO to promote breast tumor development. Functionally, silencing of NONO inhibits the growth, survival, migration and invasion, epithelial-to-mesenchymal transition (EMT), and stemness of breast cancer cells in vitro. A human metastatic breast cancer cell xenograft was established in transparent zebrafish (Danio rerio) embryos to study the metastasis inability of NONO silenced breast cancer cells in vivo. Biochemical analysis indicated NONO as a master regulator of the molecules associated with different hallmarks of cancer. Mechanistically, depletion of NONO promotes the expression of PDL1 cell surface protein in breast cancer cells. The identification of novel interactions of NONO with c-Jun and β-catenin proteins and activating the Akt/MAPK/β-catenin signalling suggests NONO as novel regulator of Akt/MAPK/β-catenin signalling pathways. Taken together, our results demonstrated an essential role of NONO in the tumorigenicity of breast cancer and could be a potential target for anti-cancerous drugs.