Abstract 1784: High expression of PTK-7 regulates the growth and invasion of triple-negative breast cancer cells

Background: Triple negative breast cancer (TNBC) is the most aggressive form of breast cancer with poor prognosis. Due to the frequent distant metastasis and lack of successful targeted therapies, the overall survival rate for the patients with TNBC is significantly lower than estrogen receptor positive and HER2 positive breast cancers. To identify potential druggable targets, previously, we performed a gene expression analysis and identified protein kinases that are highly expressed in ER-negative breast cancers. Through these studies, we discovered that the expression of pseudo kinase-7 (PTK-7) is highly elevated in TNBCs and correlated with p53 mutation status and disease progression. We hypothesize that high expression of PTK-7 is required for the growth and invasiveness of TNBC cells. Experimental design and methods: In this study, we analyzed the expression status of PTK-7 in TNBC and the association of PTK-7 expression with p53 status and disease prognosis using publicly available datasets. Protein levels of PTK-7 were determined through western blotting analysis. The association of p53 and PTK-7 expression was determined using Oncomine analysis. Using specific siRNAs against PTK-7, we determined whether PTK-7 is required for the growth of TNBC cells. The role of PTK-7 in migration and invasion of TNBC cells was determined using Boyden trans-well assays. Results: Analysis of publicly available datasets reveals that PTK-7 expression is elevated in TNBCs compared with normal breast and ER-positive breast cancers. High PTK-7 expression was found to be associated with p53 mutations. Knockdown of PTK-7 using siRNA significantly reduced the growth of TNBC cells in vitro. In vitrotrans-well migration and invasion studies also demonstrated that knockdown of PTK-7 significantly reduced the migration and invasion of TNBC cells. In contrast knockdown of PTK-7 did not affect the growth and invasiveness non-TNBC cells. Conclusion: Our results suggest that the expression of PTK-7, a critical regulator of growth and invasion of TNBCs. These results suggest that PTK-7 is a promising target for the treatment of women with TNBC. This work was supported by Susan G Komen Promise Grant (PB), SAB Komen grant (PB) and Young Foundation grant (PB). Citation Format: Lakshmi Reddy Bollu. High expression of PTK-7 regulates the growth and invasion of triple-negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1784.