A truncated phosphorylated p130Cas substrate domain is sufficient to drive breast cancer growth and metastasis formation in vivo

Abstract

Elevated p130Cas (Crk-associated substrate) levels are found in aggressive breast tumors and are associated with poor prognosis and resistance to standard therapeutics in patients. p130Cas signals majorly through its phosphorylated substrate domain (SD) that contains 15 tyrosine motifs (YxxP) which recruit effector molecules. Tyrosine phosphorylation of p130Cas is important for mediating migration, invasion, tumor promotion, and metastasis. We previously developed a Src*/SD fusion molecule approach, where the SD is constitutively phosphorylated. In a polyoma middle T-antigen (PyMT)/Src*/SD double-transgenic mouse model, Src*/SD accelerates PyMT-induced tumor growth and promotes a more aggressive phenotype. To test whether Src*/SD also drives metastasis and which of the YxxP motifs are involved in this process, full-length and truncated SD molecules fused to Src* were expressed in breast cancer cells. The functionality of the Src*/SD fragments was analyzed in vitro, and the active proteins were tested in vivo in an orthotopic mouse model. Breast cancer cells expressing the full-length SD and the functional smaller SD fragment (spanning SD motifs 6-10) were injected into the mammary fat pads of mice. The tumor progression was monitored by bioluminescence imaging and caliper measurements. Compared with control animals, the complete SD promoted primary tumor growth and an earlier onset of metastases. Importantly, both the complete and truncated SD significantly increased the occurrence of metastases to multiple organs. These studies provide strong evidence that the phosphorylated p130Cas SD motifs 6-10 (Y236, Y249, Y267, Y287, and Y306) are important for driving mammary carcinoma progression.

The miR-24-3p/p130Cas: a novel axis regulating the migration and invasion of cancer cells

“…4A). Our previous studies and others indicated that p130Cas is a proto-oncogene governing cell migration/invasion and its differential expression is related to cancer progression15162027. To test whether miR-24-3p regulates p130Cas expression, we investigated p130Cas expression in MCF7 cells after the transfection of miR-24-3p.…”

“…It has been reported that p130Cas promotes the growth and migration of cancer cells and its expression was found to be augmented in several cancers14151617. Since p130Cas has the potential as a proto-oncogene, the mechanisms regulating p130Cas expression and activity needs to be understood.…”

Breast Cancer Antiestrogen Resistance-3 (BCAR3) in Mammary Gland Development and Breast Cancer

“…For example, overexpression of Cas in MMTVHER2Neu transgenic mice accelerates the timeto tumorappearance while Cas depletion in a TGFβ driven model of mammary tumorigenesis significantly reduces tumor outgrowth (Cabodi et al, 2006, Wendt, Smith, & Schiemann, 2009. Furthermore, overexpression of the phosphorylated substrate domain of Cas in MMTVpolyoma middle T (PyMT) mice accelerates tumor growth and promote metastasis (Zhao et al, 2013;Kumbrink et al, 2016). Src activity enhances cell growth, proliferation, angiogenesis, invasion, and metastasis (Finn, 2008).…”