tranilast and Pancreatic-Neoplasms

Numerous studies have investigated the mechanism of the antitumor effect of tranilast, well known as an antiallergic drug. Herein, we investigated the mechanism of the antitumor effects of tranilast using murine PAN 02 cell line.. In an allograft mouse model, the number of metastatic sites in the liver was counted. Wound healing and chemoinvasion assay were performed to evaluate migration and invasive ability of PAN 02, respectively. Activities of matrix metalloproteinases (MMPs) were evaluated by gelatin zymography. The expression of cofactors in the activation of MMP-2 was assessed by immunohistochemical staining at the front of metastasis.. The number of metastatic sites was reduced in tranilast-treated groups. Migration ability and tumor invasiveness were significantly inhibited by tranilast in a dose-dependent manner. Gelatin zymography revealed inhibition of MMP-2 activity. Immunohistochemical staining showed remarkable attenuation of tissue inhibitor of metalloproteinase (TIMP-) 2 expression in tranilast-treated groups.. Tissue inhibitor of metalloproteinase 2 is necessary for MMP-2 activation with interaction between membrane type 1-MMP and proMMP-2. These results suggested that tranilast may inhibit MMP-2 activation through attenuating TIMP-2 expression, resulting in inhibition of tumor invasion and metastasis. Our results showed possibility of tranilast in clinical application for novel cancer therapy.

Topics: Allografts; Animals; Anti-Allergic Agents; Cell Line, Tumor; Cell Movement; Cell Proliferation; Liver Neoplasms; Matrix Metalloproteinase 2; Mice, Inbred C57BL; Neoplasm Invasiveness; Neoplasms, Experimental; ortho-Aminobenzoates; Pancreatic Neoplasms; Tissue Inhibitor of Metalloproteinase-2

Gemcitabine (Gem) is a dFdC analogue with activity against several solid tumors. Gem is intracellularly phosphorylated by dCK, leading to the production of the metabolite dFdCDP. dFdCDP exhibits the cytotoxic effect by inactivating ribonucleotide reductase larger subunit 1 (RRM1), which is a rate limiting enzyme for de novo DNA synthesis. To date, RRM1 expression is believed to determine sensitivity to Gem in pancreatic and non-small cell lung cancer. In the present study, we found that an anti-allergic drug, tranilast strongly enhanced the sensitivity of pancreatic cancer cell line KP4 to Gem. In growth inhibition assay, 100 microM of tranilast plus 1 microM of Gem more strongly suppressed the growth of KP4 at 12.7-fold in IC50 than single Gem treatment, while this compound no longer affected the sensitivity to other drugs such as 5-fluorouracil, irinotecan or paclitaxel. FACS and TUNEL analysis demonstrated the increased apoptotic population in KP4 cells under tranilast plus Gem, compared with single Gem treatment. In Western blot analysis, tranilast treatment decreased RRM1 expression at protein level with dose-dependency in KP4 cells. Proteasome inhibitor MG132 disturbed the reduction of RRM1 expression in tranilast treated KP4 cells, indicating protein degradation by the activated proteasome. Transfection using siRNA against RRM1 increased the sensitivity of KP4 to Gem, suggesting that RRM1 suppression is an important step in increasing Gem efficacy. Finally, we demonstrated that tranilast reduced RRM1 protein and increased Gem efficacy in 4 other pancreatic cell lines. In a future, a novel chemotherapeutic strategy by Gem along with tranilast might improve Gem efficacy against pancreatic cancer.

Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Blotting, Western; Cell Line, Tumor; Cell Proliferation; Cell Separation; Deoxycytidine; Drug Synergism; Flow Cytometry; Gemcitabine; Humans; In Situ Nick-End Labeling; ortho-Aminobenzoates; Pancreatic Neoplasms; Reverse Transcriptase Polymerase Chain Reaction; Ribonucleotide Reductases

The anti-tumor effect of N- [3,4-dimethoxycinnamoyl] -anthranilic acid (tranilast) was examined in experimental pancreatic cancer. Proliferation of PGHAM-1 cells was inhibited by tranilast in a dose-dependent manner, showing a significant difference at a concentration of 25 microgram/ml (p<0.05). In colony formation, tranilast reduced the number of colonies at a concentration of 25 microgram/ml (p<0.01). DNA synthesis for 12 hours was attenuated dose-dependently and a significant difference was observed at concentrations of greater than 50 microgram/ml (p<0.05). From cell cycle analysis, a dose-dependent increase in the distribution of G0-G1 phase was observed. In the dorsal air sac model, the mean angiogenesis indices in PGHAM-1 chambers were 4.17 +/- 0.22 (control group) and 2.33 +/- 0.84 (treatment group), and in VEGF chambers they were 3.60 +/- 0.67 (control group) and 1.92 +/- 0.42 (treatment group), In the peritoneal dissemination model, the quantity of sanguineous ascites, the number and the size of diaphragmatic nodules and the microvessel density (MVD) of the metastatic site were reduced by tranilast significantly. In conclusion, the anti-tumor effect of tranilast on proliferation and on tumor-angiogenesis was confirmed in experimental pancreatic cancer.

Topics: Animals; Antineoplastic Agents; Cell Division; Cricetinae; Dose-Response Relationship, Drug; Female; Mesocricetus; Neovascularization, Pathologic; ortho-Aminobenzoates; Pancreatic Neoplasms; Tumor Cells, Cultured