Abstract 5891: DCIS to invasive progression in breast cancer is delayed by restoring CCN5

Malignant progression of breast cancer from pre-invasive to invasive lesions remains a mechanistically unknown event and a major challenge in medical research. By revealing the mechanism of action, our new and substantially different approach aims to demonstrate that CCN5/WISP2 might play a role in negative regulation of progression of pre-invasive lesion ductal carcinoma in-situ (DCIS) to invasive carcinoma (IC). DCIS to IC transition results primarily from the loss of the myoepithelial cell (MEC) layer surrounding the breast ducts & lobules and basement membrane (BM) degradation followed by invasion of cancer cells into the surrounding stromal tissue and vasculature. It has been recently discovered that CCN5, a matricellular protein, is highly expressed in DCIS patient specimens and facilitates regression of aggressive phenotypes. Our in-vitro studies with myoepithelial cell lines (MECs) indicate that CCN5 may prevent the DCIS to IC transition through the protection of the MEC layer. CCN5 performs it’s protective role by regulating sonic hedgehog (SHh) expression in MECs. It has been previously shown in separate studies that Neuropilin1 (Nrp1) positively regulates expression of SHh and Nrp1 is exclusively expressed in MEC layer in breast tissues. An extension of our studies indicate that CCN5 might regulate the integrity of the mammary ductal architecture by protecting the MEC layer through a novel Nrp1-SHh signaling axis. Collectively, our studies indicate that regulating CCN5 expression level in breast cancer tissues might help us controlling the rate of progression of the disease from DCIS to an invasive stage. Citation Format: Sandipto Sarkar, Arnab Ghosh, Gargi Maity, Snigdha Banerjee, Sushanta Banerjee. DCIS to invasive progression in breast cancer is delayed by restoring CCN5 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5891. doi:10.1158/1538-7445.AM2017-5891