Therapeutic targeting of C-terminal binding protein in human cancer.

Abstract

The CtBP transcriptional corepressors promote cancer cell survival and migration/invasion. CtBP senses cellular metabolism via a regulatory dehydrogenase domain, and is antagonized by p14/p19(ARF) tumor suppressors. The CtBP dehydrogenase substrate 4-methylthio-2-oxobutyric acid (MTOB) can act as a CtBP inhibitor at high concentrations, and is cytotoxic to cancer cells. MTOB induced apoptosis was p53-independent, correlated with the derepression of the proapoptotic CtBP repression target Bik, and was rescued by CtBP overexpression or Bik silencing. MTOB did not induce apoptosis in mouse embryonic fibroblasts (MEFs), but was increasingly cytotoxic to immortalized and transformed MEFs, suggesting that CtBP inhibition may provide a suitable therapeutic index for cancer therapy. In human colon cancer cell peritoneal xenografts, MTOB treatment decreased tumor burden and induced tumor cell apoptosis. To verify the potential utility of CtBP as a therapeutic target in human cancer, the expression of CtBP and its negative regulator ARF was studied in a series of resected human colon adenocarcinomas. CtBP and ARF levels were inversely-correlated, with elevated CtBP levels (compared with adjacent normal tissue) observed in greater than 60% of specimens, with ARF absent in nearly all specimens exhibiting elevated CtBP levels. Targeting CtBP may represent a useful therapeutic strategy in human malignancies.

• Authors: Michael W Straza, Seema Paliwal, Ramesh C Kovi, Barur Rajeshkumar, Peter Trenh, Daniel Parker, Giles F Whalen, Stephen Lyle, Celia A Schiffer, Steven R Grossman
• Journal: Cell cycle (Georgetown, Tex.) (Cell Cycle) Vol. 9 Issue 18 Pg. 3740-50 (Sep 15 2010) ISSN: 1551-4005 [Electronic] United States
• PMID: 20930544 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Antineoplastic Agents
• Apoptosis Regulatory Proteins
• BIK protein, human
• DNA-Binding Proteins
• Membrane Proteins
• Mitochondrial Proteins
• Repressor Proteins
• Tumor Suppressor Protein p53
• 2-keto-4-methylthiobutyric acid
• Methionine
• Alcohol Oxidoreductases
• C-terminal binding protein

Topics

• Alcohol Oxidoreductases (antagonists & inhibitors, chemistry, metabolism)
• Animals
• Antineoplastic Agents (pharmacology)
• Apoptosis
• Apoptosis Regulatory Proteins (genetics, metabolism)
• Chromatin Immunoprecipitation
• Colonic Neoplasms (metabolism)
• DNA-Binding Proteins (antagonists & inhibitors, chemistry, metabolism)
• HCT116 Cells
• Humans
• Membrane Proteins (genetics, metabolism)
• Methionine (analogs & derivatives, pharmacology)
• Mice
• Mice, Nude
• Mitochondrial Proteins
• Repressor Proteins (antagonists & inhibitors, chemistry, metabolism)
• Transplantation, Heterologous
• Tumor Suppressor Protein p53 (metabolism)