title: Tolfenamic acid inhibits esophageal cancer through repression of specificity proteins and c-Met.
abstract: The non-steroidal anti-inflammatory drug tolfenamic acid (TA) inhibits proliferation of SEG-1 and BIC-1 esophageal cancer cells with half-maximal growth inhibitory concentration values of 36 and 48 muM, respectively. TA also increased Annexin V staining in both cell lines, indicative of proapoptotic activity. Treatment of SEG-1 and BIC-1 cells with TA for up to 72 h decreased expression of specificity protein (Sp) transcription factors Sp1, Sp3 and Sp4 and this was accompanied by decreased expression of the well-characterized Sp-regulated genes cyclin D1, vascular endothelial growth factor and survivin. TA also decreased hepatocyte growth factor receptor, (c-Met), a receptor tyrosine kinase that is overexpressed in esophageal cancer cells and tumors and is an important drug target. Knockdown of Sp1, Sp3 and Sp4 by RNA interference in SEG-1 and BIC-1 cells also decreased c-Met expression, demonstrating that c-Met is an Sp-regulated gene in esophageal cancer cells. Sp1 was overexpressed in esophageal cancer cells and tumors and increased Sp1 staining was observed in esophageal tumors from patients. TA (20 mg/kg/day) also decreased tumor growth and weight in athymic nude mice bearing SEG-1 cells as xenografts and this was accompanied by increased apoptosis and decreased Sp1 and c-Met staining in tumors from treated mice. Thus, TA-dependent downregulation of Sp transcription factors and c-Met defines a novel chemotherapeutic approach for treatment of esophageal cancer.
authors.affiliation: Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466, USA.
authors.forename: Sabitha
authors.initials: S
authors.lastname: Papineni
authors.forename: Sudhakar
authors.initials: S
authors.lastname: Chintharlapalli
authors.forename: Maen
authors.initials: M
authors.lastname: Abdelrahim
authors.forename: Syng-ook
authors.initials: SO
authors.lastname: Lee
authors.forename: Robert
authors.initials: R
authors.lastname: Burghardt
authors.forename: Ala
authors.initials: A
authors.lastname: Abudayyeh
authors.forename: Cheryl
authors.initials: C
authors.lastname: Baker
authors.forename: Luis
authors.initials: L
authors.lastname: Herrera
authors.forename: Stephen
authors.initials: S
authors.lastname: Safe
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D045744:Cell Line, Tumor; D015536:Down-Regulation; D004938:Esophageal Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D019859:Proto-Oncogene Proteins c-met / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051703:Sp Transcription Factors / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014183:Transplantation, Heterologous; D062367:ortho-Aminobenzoates / Q000494:pharmacology*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D051703:Sp Transcription Factors; D062367:ortho-Aminobenzoates; C009500:tolfenamic acid; D019859:Proto-Oncogene Proteins c-met