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Chemical probes that target Stat3 to treat cancer

Award Information

Agency:
Department of Health and Human Services
Branch:
N/A
Award ID:
Program Year/Program:
2012 / STTR
Agency Tracking Number:
R41CA153658
Solicitation Year:
2012
Solicitation Topic Code:
NCI
Solicitation Number:
PA11-097
Small Business Information
STEMMED, LTD
8100 WASHINGTON AVE, STE 1000 HOUSTON, TX 77007-1059
View profile »
Woman-Owned: Yes
Minority-Owned: No
HUBZone-Owned: No
 
Phase 1
Fiscal Year: 2012
Title: Chemical probes that target Stat3 to treat cancer
Agency: HHS
Contract: 1R41CA153658-01A1
Award Amount: $277,365.00
 

Abstract:

DESCRIPTION (provided by applicant): We have shown for the first time in human breast cancer patients that residual tumors after standard chemotherapy are enriched for a CD44+/CD24-/low population of breast cancer stem or tumor-initiating cells (TIC) thatexhibit enhanced mammosphere-forming efficiency (MSFE) and display an increase in xenograft transplant outgrowths in mice (1, 2, 11). In addition, we have determined from gene expression analysis and shRNA library screening of the CD44+/CD24-/low-mammosphere-forming population that the top canonical pathways involved in breast TIC self-renewal include Stat3 signaling (3). Using virtual ligand screening, we identified three small-molecule probes that target the Src homology (SH) 2 domain of Stat3 and that competitively and selectively inhibited Stat3 activation (5). The most active of these hits, C188, was shown to dramatically reduce human-into-mouse breast cancer tumorgraft volumes and to increase tumor-free survival of engrafted mice 4-fold when used in combination with standard chemotherapy (3). We performed 2-D similarity screening using the scaffold of C188 as the query structure and a commercial compound library (Life Chemicals) followed by 3-D pharmacophore analysis and identified 33 active derivatives. One derivative (C188-9), now owned by StemMed, is 1-log more active than C188 at inhibiting Stat3 binding in SPR assays and in blocking ligand-mediated Stat3 phosphorylation (6). In addition, C188-9 exhibited minimal toxicity in mice up to a dose of 100mg/kg/day for 14 days, did not inhibit normal murine bone marrow colony formation in vitro, and, prevented weight loss and sarcopenia in a murine model of cachexia. The specific hypothesis that will be examined in this Phase I STTR is that C188-9 or one ofits derivatives will be highly active against Stat3, will be well tolerated in mice, and will demonstrate efficacy in breast tumorgraft models. We have proposed 2 tightly focused specific aims to pursue this hypothesis: AIM 1: To synthesize candidate third (3rd) generation C188 probes based on modifications of the C188-9 lead structure and to identify those with increased potency and favorable ADMET features. Synthesis of new probes is straightforward; probes with greater potency and favorable ADMET features will be identified using well-established assays. AIM 2. To examine the most potent and least toxic 3rd generation Stat3 probes for the ability to target breast TICs and inhibi tumorgraft growth when used in combination with standard chemotherapy. Two C188-9 derivatives that are the most potent, least toxic, and have the best ADMET profile will be examined for the ability to target TIC and inhibit tumor growth when combined with standard chemotherapy using the most informative subset of the 29 breast tumorgraft models we have developed. These studies will set the stage for a Phase II STTR application in which we will propose GMP synthesis and in vivo ADMET studies of the most promising lead compound identified in preparation for a Phase I clinical trial in metastatic breast cancer. PUBLIC HEALTH RELEVANCE: Successfully curing cancers that are resistant to standard chemotherapy will require new drugs including those directed at a subset of cancer cells referred to as cancer stem cells. Cancer stemcells are resistant to standard chemotherapy and are responsible for tumor recurrence. We have identified a pathway in breast cancer stem cells essential for their survival that involves a protein called Stat3 and propose in this application t develop potent and selective small-molecule inhibitors of Stat3 for development into a novel and effective drug treatment for metastatic breast cancer.

Principal Investigator:

David J. Tweardy
713-798-8918
dtweardy@bcm.edu

Business Contact:

Prof D. John
713-798-8919
dtweardy@bcm.edu
Small Business Information at Submission:

STEMMED, LTD
8100 WASHINGTON AVE, STE 1000 HOUSTON, TX 77007-1059

EIN/Tax ID: 127075273
DUNS: N/A
Number of Employees: N/A
Woman-Owned: Yes
Minority-Owned: No
HUBZone-Owned: No
Research Institution Information:
BAYLOR COLLEGE OF MEDICINE
BAYLOR COLLEGE OF MEDICINE
1 BAYLOR PLAZA MS-310
HOUSTON, TX 77030-3411
Contact: