Knockdown of CKAP2 Inhibits Proliferation, Migration, and Aggregate Formation in Aggressive Breast Cancer

SIMPLE SUMMARY: Cancer is a complex disease where cells grow and divide in an uncontrolled manner. It is well established that its development and progression involve major alterations in the activity of mitotic regulators. In order to improve our understanding of the contribution of cell-cycle progression defects to the development of disease, the aim of this study is to identify genes relevant to the proper progression of mitosis that are deregulated in breast cancer. Our findings identified CKAP2 as an important mitotic regulator in BC tumors. Moreover, in vitro experiments showed that gene silencing of CKAP2 blocked cell growth, cell migration, and formation of cell aggregates. These results demonstrated the important role of CKAP2 in breast cancer tumor formation. ABSTRACT: Loss of mitotic regulation is commonly observed in cancer and is a major cause of whole-chromosome aneuploidy. The identification of genes that play a role in the proper progression of mitosis can help us to understand the development and evolution of this disease. Here, we generated a list of proteins implicated in mitosis that we used to probe a patient-derived breast cancer (BC) continuum gene-expression dataset generated by our group by human transcriptome analysis of breast lesions of varying aggressiveness (from normal to invasive). We identified cytoskeleton-associated protein 2 (CKAP2) as an important mitotic regulator in invasive BC. The results showed that CKAP2 is overexpressed in invasive BC tumors when compared with normal tissues, and highly expressed in all BC subtypes. Higher expression of CKAP2 is also related to a worse prognosis in overall survival and relapse-free survival in estrogen receptor (ER)-positive and human epidermal growth factor receptor type 2 (HER2)-negative BC patients. Knockdown of CKAP2 in SKBR3 cells impaired cell proliferation and cell migration and reduced aggregate formation in a 3D culture. Our results show the important role of CKAP2 in BC tumorigenesis, and its potential utility as a prognostic marker in BC.