Data from ASR490, a Small Molecule, Overrides Aberrant Expression of <i>Notch1</i> in Colorectal Cancer

Abstract

<div>Abstract<p><i>Notch1</i> activation triggers significant oncogenic signaling that manifests as enhanced metastatic potential and tumorigenesis in colorectal cancer. Novel small-molecule inhibitors, mainly plant-derived analogs, have low toxicity profiles and higher bioavailability. In this study, we have developed a small molecule, ASR490, by modifying structure of naturally occurring compound Withaferin A. ASR490 showed a growth-inhibitory potential by downregulating <i>Notch1</i> signaling in HCT116 and SW620 cell lines. Docking studies and thermal shift assays confirmed that ASR490 binds to <i>Notch1</i>, whereas no changes in <i>Notch2</i> and <i>Notch3</i> expression were seen in colorectal cancer cells. <i>Notch1</i> governs epithelial-to-mesenchymal transition signaling and is responsible for metastasis, which was abolished by ASR490 treatment. To further confirm the therapeutic potential of ASR490, we stably overexpressed <i>Notch1</i> in HCT-116 cells and determined its inhibitory potential in transfected colorectal cancer (Notch1/HCT116) cells. ASR490 effectively prevented cell growth in both the vector (<i>P</i> = 0.005) and <i>Notch1</i> (<i>P</i> = 0.05) transfectants. The downregulation of <i>Notch1</i> signaling was evident, which corresponded with downregulation of mesenchymal markers, including <i>N-cadherin</i> and <i>β-catenin</i> and induction of <i>E-cadherin</i> in HCT-116 transfectants. Intraperitoneal administration of a 1% MTD dose of ASR490 (5 mg/kg) effectively suppressed the tumor growth in control (pCMV/HCT116) and Notch1/HCT116 in xenotransplanted mice. In addition, downregulation of <i>Notch1</i> and survival signaling in ASR-treated tumors confirmed the <i>in vitro</i> results. In conclusion, ASR490 appears to be a potent agent that can inhibit <i>Notch1</i> signaling in colorectal cancer.</p></div>