Tolfenamic acid and pancreatic cancer growth, angiogenesis, and Sp protein degradation.
BACKGROUND
Sp1, Sp3, and Sp4 are transcription factors that regulate cell proliferation and vascular endothelial growth factor (VEGF) expression and are overexpressed in many cancer cell lines. For some cancers, Sp1 overexpression is associated with poor survival. Cyclooxygenase inhibitors decrease Sp1 expression in cancer cells, and therefore different structural classes of nonsteroidal anti-inflammatory drugs (NSAIDs) were screened for their ability to decrease levels of Sp1, Sp3, and Sp4 and to decrease pancreatic tumor growth and metastasis in an in vivo model.


METHODS
Levels of Sp1, Sp3, Sp4, and VEGF proteins in pancreatic cancer cell lines were assessed by immunoblot analysis. mRNA was assessed by reverse transcription-polymerase chain reaction. Panc-1 pancreatic cancer cells transfected with VEGF promoter constructs were used to assess VEGF promoter activation. Pancreatic tumor weight and size and liver metastasis were assessed in an orthotopic mouse model of pancreatic cancer (groups of 10 mice). Protein expression in tumors was assessed immunohistochemically.


RESULTS
Tolfenamic acid and structurally related biaryl derivatives induced degradation of Sp1, Sp3, and Sp4 in pancreatic cancer cells. Tolfenamic acid also inhibited VEGF mRNA and protein expression in pancreatic cancer cells; this inhibition was associated with the decreased Sp-dependent activation of the VEGF promoter. In the mouse model for pancreatic cancer, treatment with tolfenamic acid (50 mg/kg of body weight), compared with control treatment, statistically significantly decreased tumor growth and weight (P = .005), liver metastasis (P = .027), and levels of Sp3 and VEGF (P = .009) and Sp1 and Sp4 (P = .006) proteins in tumors. For example, tumors from mice treated with tolfenamic acid (50 mg/kg) had statistically significantly lower VEGF levels (45%, 95% confidence interval = 39% to 51%; P = .009) than tumors from control mice.


CONCLUSIONS
Tolfenamic acid is a new antipancreatic cancer NSAID that activates degradation of transcription factors Sp1, Sp3, and Sp4; reduces VEGF expression; and decreases tumor growth and metastasis.
Abdelrahim
Maen
M
Institute of Biosciences and Technology, Health Science Center, Texas A&M University, Houston, TX 77843-4466, USA.
Baker
Cheryl H
CH
Abbruzzese
James L
JL
Safe
Stephen
S
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000494:pharmacology*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D003841:Deoxycytidine / Q000031:analogs & derivatives / Q000494:pharmacology; D024202:Electrophoretic Mobility Shift Assay; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D047569:Laser Scanning Cytometry; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000188:drug therapy / Q000517:prevention & control; D010190:Pancreatic Neoplasms / Q000098:blood supply / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051703:Sp Transcription Factors / Q000187:drug effects / Q000378:metabolism*; D016329:Sp1 Transcription Factor / Q000378:metabolism; D051705:Sp3 Transcription Factor / Q000378:metabolism; D051706:Sp4 Transcription Factor / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*; D062367:ortho-Aminobenzoates / Q000494:pharmacology*; D000093542:Gemcitabine
D000894:Anti-Inflammatory Agents, Non-Steroidal; D000970:Antineoplastic Agents; D016861:Cyclooxygenase Inhibitors; D012333:RNA, Messenger; D051703:Sp Transcription Factors; D016329:Sp1 Transcription Factor; D051706:Sp4 Transcription Factor; D042461:Vascular Endothelial Growth Factor A; D062367:ortho-Aminobenzoates; D003841:Deoxycytidine; D051705:Sp3 Transcription Factor; C009500:tolfenamic acid; D008156:Luciferases; D000093542:Gemcitabine