Tumor-associated myoepithelial cells promote the invasive progression of ductal carcinoma in situ through activation of TGF{beta} signaling [RNA]

The normal myoepithelium has a tumor-suppressing nature and inhibits the progression of ductal carcinoma in situ (DCIS) into invasive ductal carcinoma (IDC). Conversely, a growing number of studies have shown that tumor-associated myoepithelial cells have a tumor-promoting effect. Moreover, the exact role of tumor-associated myoepithelial cells in the DCIS-to-IDC development remains undefined. To address this, we explored the role of tumor-associated myoepithelial cells in the DCIS-to-IDC progression. We developed a direct coculture system to study the cell-cell interactions between DCIS cells and tumor-associated myoepithelial cells. Coculture studies indicated that tumor-associated myoepithelial cells promoted the invasive progression of a DCIS cell model in vitro, and mechanistic studies revealed that the interaction with DCIS cells stimulated tumor-associated myoepithelial cells to secrete TGFβ1, which subsequently contributed to activating the TGFβ/Smads pathway in DCIS cells. We noted that activation of the TGFβ signaling pathway promoted the epithelial-mesenchymal transition (EMT), basal-like phenotypes, stemness, and invasiveness of DCIS cells. Importantly, xenograft studies further demonstrated that tumor-associated myoepithelial cells enhanced the DCIS-to-IDC progression in vivo. Furthermore, we found that TGFβ-mediated induction of oncogenic miR-10b-5p expression and downregulation of RB1CC1, a miR-10b-5p-targeted tumor suppressor gene, contributed to the invasive progression of DCIS. Our findings provide the first experimental evidence to directly support the paradigm that altered DCIS-associated myoepithelial cells promote the invasive progression of DCIS into IDC via TGFβ signaling activation.

from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2qOFiZO
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