Effective therapies for CRC still remain a critical unmet medical need. One of the most important drivers of CRC is K-Ras, which is mutated in 40% of human CRCs. Indeed, Ras proteins play essential roles as molecular switches, controlling cell proliferation, growth, differentiation, and apoptosis. Deregulation of the Ras signaling pathway by activating mutations, overexpression, or upstream activation is common in many human tumors. Thus, K-Ras represents a highly validated and important target for CRC and a wide variety of other cancers. Although a number of different approaches have been attempted to target upstream or downstream proteins in the K-Ras signaling pathway, it would be ideal to target K-Ras itself However, KRas is considered to be a poor drug target. In order to test whether K-Ras could be druggable with a small molecule, we cloned, expressed, isotopically labeled, and purified K-Ras (G12D) and conducted a fragment-based screen on GDP- and GTP-bound K-Ras using NMR. In these screens we identified over 100 small molecules that bind to K-Ras, suggesting that K-Ras may be a druggable target. In addition, we obtained several X-ray crystal structures of K-Ras bound to the hits identified in the screen, which we are currently using to guide the synthesis of K-Ras inhibitors. We propose to discover small molecules that potently bind to K-Ras, inhibit its functions, and are highly efficacious against in vivo CRC tumor models with the goal of discovering a compound that is suitable for entry into a CRC clinical trial. We hypothesize that a K-Ras inhibitor will be highly effective for treating CRC patients.
Aim 1. Generate lead compounds that bind K-RAS tightly (nM) from our fragment-based screens and recently determined three-dimensional structures of K-RAS/inhibitor complexes using iterative structure-based design.
Aim 2. Optimize lead K-RAS binders for their K-RAS inhibitory effects in biochemical assays and their cell-based activities against colon cancer cells.
Aim 3. Prioritize K-RAS inhibitors with excellent pharmaceutical properties that are efficacious in vivo using a new stem cell-derived, tamoxifen-inducible Cre driver (Lrig1-CreERT2) mouse to activate mutant KRAS in the mouse colon. Select a compound that is suitable for a clinical trial in colon cancer by the end of the granting period.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Specialized Center (P50)
Project #
5P50CA095103-12
Application #
8557695
Study Section
Special Emphasis Panel (ZCA1-RPRB-M)
Project Start
Project End
Budget Start
2013-05-01
Budget End
2014-04-30
Support Year
12
Fiscal Year
2013
Total Cost
$133,427
Indirect Cost
Name
Vanderbilt University Medical Center
Department
Type
DUNS #
004413456
City
Nashville
State
TN
Country
United States
Zip Code
37212
Singh, Kshipra; Coburn, Lori A; Asim, Mohammad et al. (2018) Ornithine Decarboxylase in Macrophages Exacerbates Colitis and Promotes Colitis-Associated Colon Carcinogenesis by Impairing M1 Immune Responses. Cancer Res 78:4303-4315
Idrees, Kamran; Padmanabhan, Chandrasekhar; Liu, Eric et al. (2018) Frequent BRAF mutations suggest a novel oncogenic driver in colonic neuroendocrine carcinoma. J Surg Oncol 117:284-289
Zhang, Qin; Jeppesen, Dennis K; Higginbotham, James N et al. (2018) Mutant KRAS Exosomes Alter the Metabolic State of Recipient Colonic Epithelial Cells. Cell Mol Gastroenterol Hepatol 5:627-629.e6
Choksi, Yash A; Reddy, Vishruth K; Singh, Kshipra et al. (2018) BVES is required for maintenance of colonic epithelial integrity in experimental colitis by modifying intestinal permeability. Mucosal Immunol 11:1363-1374
Saito-Diaz, Kenyi; Benchabane, Hassina; Tiwari, Ajit et al. (2018) APC Inhibits Ligand-Independent Wnt Signaling by the Clathrin Endocytic Pathway. Dev Cell 44:566-581.e8
Davenport, James R; Su, Timothy; Zhao, Zhiguo et al. (2018) Modifiable lifestyle factors associated with risk of sessile serrated polyps, conventional adenomas and hyperplastic polyps. Gut 67:456-465
Liu, Qi; Herring, Charles A; Sheng, Quanhu et al. (2018) Quantitative assessment of cell population diversity in single-cell landscapes. PLoS Biol 16:e2006687
Means, Anna L; Freeman, Tanner J; Zhu, Jing et al. (2018) Epithelial Smad4 Deletion Up-Regulates Inflammation and Promotes Inflammation-Associated Cancer. Cell Mol Gastroenterol Hepatol 6:257-276
Weiss, Vivian L; Kiernan, Colleen; Wright, Jesse et al. (2018) Fine-Needle Aspiration-Based Grading of Pancreatic Neuroendocrine Neoplasms Using Ki-67: Is Accurate WHO Grading Possible on Cytologic Material? J Am Soc Cytopathol 7:154-459
Roberts, Jordan; Gonzalez, Raul S; Revetta, Frank et al. (2018) Mesenteric tumour deposits arising from small-intestine neuroendocrine tumours are frequently associated with fibrosis and IgG4-expressing plasma cells. Histopathology 73:795-800

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