withaferin-a and Carcinoma--Ehrlich-Tumor

The eukaryotic translation initiation factor 4E (eIF4E) is considered as a key survival protein involved in cell cycle progression, transformation and apoptosis resistance. Herein, we demonstrate that medicinal plant derivative 3-AWA (from Withaferin A) suppressed the proliferation and metastasis of CaP cells through abrogation of eIF4E activation and expression via c-FLIP dependent mechanism. This translational attenuation prevents the de novo synthesis of major players of metastatic cascades viz. c-FLIP, c-Myc and cyclin D1. Moreover, the suppression of c-FLIP due to inhibition of translation initiation complex by 3-AWA enhanced FAS trafficking, BID and caspase 8 cleavage. Further ectopically restored c-Myc and GFP-HRas mediated activation of eIF4E was reduced by 3-AWA in transformed NIH3T3 cells. Detailed underlying mechanisms revealed that 3-AWA inhibited Ras-Mnk and PI3-AKT-mTOR, two major pathways through which eIF4E converges upon eIF4F hub. In addition to in vitro studies, we confirmed that 3-AWA efficiently suppressed tumor growth and metastasis in different mouse models. Given that 3-AWA inhibits c-FLIP through abrogation of translation initiation by co-targeting mTOR and Mnk-eIF4E, it (3-AWA) can be exploited as a lead pharmacophore for promising anti-cancer therapeutic development.

Topics: Adaptor Proteins, Signal Transducing; Adenosine Triphosphatases; Animals; Carcinoma, Ehrlich Tumor; Carrier Proteins; CASP8 and FADD-Like Apoptosis Regulating Protein; Caspase 8; Cation Transport Proteins; Cell Cycle Proteins; Cell Line, Tumor; Cell Movement; Copper-Transporting ATPases; Disease Models, Animal; Eukaryotic Initiation Factor-4E; Eukaryotic Initiation Factors; fas Receptor; Humans; Male; Mice; Neoplasm Metastasis; Phosphatidylinositol 3-Kinases; Phosphoproteins; Phosphorylation; Protein Biosynthesis; Protein Transport; Proto-Oncogene Proteins c-akt; ras Proteins; Signal Transduction; TOR Serine-Threonine Kinases; Withanolides

The antitumor and radiosensitizing effects of withaferin A (WA), a steroidal lactone from Withania somnifera, was studied on Ehrlich ascites carcinoma in vivo. The acute LD50(14) for WA in Swiss mice was approximately 80 mg/kg. Twenty-four hours after i.p. inoculation of 10(6) tumor cells, WA was injected i.p. at different dose fractions (5 or 7.5 mg/kg x 8, 10 mg/kg x 5, 20 or 30 mg/kg x 2) with or without abdominal gamma irradiation (RT, 75. Gy) after the first drug dose. Increase in life span and tumor-free survival were studied up to 120 days. The drug inhibited tumor growth and increased survival, which was dependent on the WA dose per fraction rather than the total dose. Combination of RT with all the drug schedules increased tumor cure and tumor-free survival, the best effect seen after 2 fractions of 30 mg/kg each. In another experiment WA was given as 2 (40 mg/kg x 2), 3 (30 mg/kg x 3) or 4 (20 mg/kg x 4) fractions at 5, 7 or 10 days after tumor inoculation with or without RT after the first drug dose. At 7 and 10 days after inoculation the drug was effective only at 40 mg/kg x 2, but with RT 30 mg/kg x 3 produced an equal effect (20% survival) on 7 day old tumors.

Topics: Abdominal Neoplasms; Animals; Antineoplastic Agents, Phytogenic; Carcinoma, Ehrlich Tumor; Cobalt Radioisotopes; Combined Modality Therapy; Disease-Free Survival; Dose-Response Relationship, Drug; Ergosterol; Female; Injections, Intraperitoneal; Lethal Dose 50; Longevity; Male; Mice; Radiation-Sensitizing Agents; Radioisotope Teletherapy; Radiotherapy Dosage; Remission Induction; Survival Rate; Withanolides

Adult Swiss albino mice were inoculated intraperitoneally (i.p.) with 10 (6) Ehrlich ascites carcinoma cells. Twenty-four hours later they were given an i.p. injection of 10-60 mg/kg of withaferin A (WA), isolated from the roots of Withania somnifera. The tumor growth and tumor free animal survival were studied for up to 120 days. In another experiment 30 mg/kg WA was injected i.p. to mice at 1, 3 or 5 days after tumor cell injection with or without acute abdominal exposure to 7.5 Gy gamma radiation and the tumor growth and 120-day survival were studied. WA inhibited tumor growth and increased tumor free survival in a dose-dependent manner. The drug ED50 for 120-day survival was approximately 30 mg/kg body wt. Drug treatment before irradiation synergistically increased 120-day even in advanced tumors. A dose of 30 mg/kg seems to be optimum for combination with radiation.

Topics: Animals; Antineoplastic Agents, Phytogenic; Carcinoma, Ehrlich Tumor; Dose-Response Relationship, Drug; Ergosterol; Female; Gamma Rays; Male; Mice; Mice, Inbred Strains; Radiation-Sensitizing Agents; Withanolides