NOV (Nephroblastoma OVerexpressed) C-ter (NOV C-ter) is the carboxy-terminal sequence (170aa) of NOV/CCN3 protein. NOV/CCN3 (357aa), a member of CCN family, is secreted by quiescent endothelial cells and is involved in the regulation of various cellular functions including angiogenesis, proliferation, differentiation, survival, adhesion and migration. Although NOV C-ter does not have a direct cytotoxic effect when tested on a large panel of human cell lines including the NCI 60 cell lines (NCI Drug Screening Program), our data demonstrates significant anti-angiogenic and anti-tumor effects in a variety of experimental models. NOV C-ter inhibits in vitro endothelial cell tube formation in a dose-dependent fashion, using endothelial cells derived from porcine aorta, human microvasculature, or human umbilical vein (HUVECs). In addition, NOV C-ter impairs HUVEC proliferation, migration, invasion and adhesion. Interestingly, inhibition of HUVEC proliferation occurs via interference with growth-promoting signals involving Apelin-13 and adenomedullin. Furthermore, NOV C-ter specifically reduced phosphorylation of PI3K/Akt in endothelial cells, with no significant effect on the p44/42 (ERK1/2) pathway. In vivo, NOV C-ter had significant anti-tumor effect as a single agent in a murine glioblastoma xenograft model using human X-12 culture-adapted cells and in a nude mouse xenograft model using human non-small-cell lung cancer cells (A549). In these two systems, NOV C-ter provided superior survival benefit compared to treatment with bevacizumab or vehicle (PBS). Similarly, NOV C-ter significantly increased overall survival versus vehicle (PBS), an effect which was comparable to temozolomide treatment, in a murine syngeneic orthotopic glioblastoma model using the GL-261 cell line. To directly study the effect of NOV C-ter on angiogenesis, we treated zebrafish embryos prior to the onset of angiogenesis, and found a considerable reduction in vessel formation compared to bevacizumab-treated or untreated zebrafish. NOV C-ter also reduced tumor neovascularization in human breast cancer (T47D cell line) implanted in zebrafish. In summary, NOV C-ter demonstrates anti-angiogenic and tumoricidal effects via a novel mechanism of action. Mechanistic studies of NOV C-ter are underway to evaluate its precise effects on key signaling pathways in endothelial cells. Preclinical pharmacology and toxicology studies are also underway with a plan to advance to early-phase clinical trials.
Citation Format: Junfeng Luo, Yong Teng, Minghui Li, Theodore S. Johnson, Franck Cuttitta, Zhengtao Chu, Xiaoyang Qi, John K. Cowell, Olivier Rixe. NOV C-ter: A novel preclinical anti-angiogenic agent. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1023. doi:10.1158/1538-7445.AM2014-1023