Supporting data for "The Role of Planar Cell Polarity in Mammary Gland Development and Tumorigenesis"

Planar cell polarity (PCP) is a fundamental mechanism that provides directional information to ensure coordinated cellular behaviors in a group of cells. It plays a vital role in the development and function of a multitude of organs such as brain, inner ear, and skin. We found that the core PCP protein Vangl2 is abundantly expressed in mammary epithelial cells, exhibiting an asymmetric distribution. Our data reveals that the genetic ablation of Vangl2, along with its homologue Vangl1, results in a significant impairment of mammary gland morphogenesis, indicating their critical roles in this biological process. Notably, both Vangl1 and Vangl2 are highly expressed in mammary tumors and have been linked to a negative prognosis in breast cancer patients. Interestingly, we found that genetic ablation of Vangl1 and Vangl2 in cancer cells or in a spontaneous breast cancer PyMT mouse model does not influence the primary tumor growth, but markedly inhibits cancer metastasis. Prior research has shown that metastasis, a lethal factor in breast cancer progression, is strongly associated with the presence of circulating tumor cell (CTC) clusters in the bloodstream. However, the factors modulating the abundance of these CTC clusters remain largely unclear. Our results suggested that Vangl1 and Vangl2 play a significant role in promoting breast cancer metastasis by modulating the formation of CTC clusters within the bloodstream, by regulating the expression of laminin. Collectively, our findings unveil an important function of PCP in both mammary gland development and tumorigenesis.This dataset contains the raw data for the above project.