The Role of Versican in Modulating Breast Cancer Cell Self-renewal

Abstract

Versican is highly expressed during the early stages of tissue development and its expression is elevated during wound repair and tumor growth. There is little literature on the potential role of breast cancer stem cells on the cellularextracellular matrix interactions involving versican. An anti-versican short hairpin RNA (shRNA) was used to observe the effect of reduction of versican on breast cancer self-renewal. A versican G3 construct was exogenously expressed in breast cancer cell lines. Colony formation and mammosphere formation assays were conducted; flow cytometry was applied to analyze the prevalence of side population cells. The versican G3-and vector-transfected 66c14 cells were injected transdermally into BALB/c mice as a 10-fold dilution series from 1 Â 10 5 to 1 Â 10 2 cells per mouse. Versican G3 domain enhanced breast cancer self-renewal in both experimental in vitro and in vivo models. Versican G3-transfected cells contained high levels of side population cells, formed more mammospheres when cultured in the serum-free medium, and formed a greater number and larger colonies. Reduction of versican's functionality through anti-versican shRNA or knocking out the EGF-like motifs reduced the effect of versican on enhancing mammosphere and colony formation. Versican-enhanced self-renewal played a role in enhanced chemotherapeutic drug resistance, relating partly to the upregulated expression of EGF receptor (EGFR) signaling. Versican is highly expressed in breast cancer progenitor cells and was maintained at high levels before cell differentiation.

Insights into the key roles of proteoglycans in breast cancer biology and translational medicine

“…G3-induced EGFR/AKT/GSK-3β (S9P) signaling in breast cancer cells also enhances breast cancer cell self-renewal both in vitro and in vivo . In this model, versican is highly expressed in breast cancer progenitor cells and confers resistance to chemotherapeutic drugs [56]. It is obvious that accumulated versican in ECM is capable of stimulating several cell types through activation of various signaling pathways promoting the secretion of inflammatory mediators that augment tumor growth and metastasis.…”

The wound healing, chronic fibrosis, and cancer progression triad

“…This proteoglycan interacts with multiple ECM and cell surface components, promoting cell proliferation, cell motility, and metastasis (301,310,382). Intriguingly, in breast cancer, versican has been associated with chemotherapy resistance related to EGFR hypersignaling and enhanced cancer cell self-renewal (78,79). Moreover, versican synthesis appears to be upregulated by TAFs in the ovarian cancer stroma (407) where TGF-␤ signaling triggers versican expression, and together they contribute to promote ovarian cancer aggressiveness (407).…”

Expression of microRNA miR-17-3p inhibits mouse cardiac fibroblast senescence by targeting Par4

“…The stained cells were analyzed by flow cytometry using a dual-wavelength analysis (blue, 424-444 nm; red, 675 nm) after excitation with 350-nm UV light. Side population cell analysis was performed as previously described (Du et al, 2013b;Fang et al, 2013).…”