naphthoquinones and Intestinal-Neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) represent a rare and heterogenous tumor entity. Importantly, the highly proliferative subgroup of neuroendocrine carcinoma (GEP-NEC) is characterized by high resistance to conventional chemotherapy. Consequently, there is an urgent need to identify novel therapeutic targets, especially for GEP-NEC. Thus, we focused on Inhibitor of apoptosis protein (IAP) family members survivin and XIAP that orchestrate inhibition of apoptosis, induce resistance against chemotherapeutics and facilitate tumor metastasis. Copy number gains (CNGs) could be detected by microarray comparative genomic hybridization for survivin and XIAP in 60 % and 26.7 % of all GEP-NENs, respectively. Immunohistochemical staining of tissue specimens from 77 consecutive patients with GEP-NEN demonstrated increased survivin protein expression levels in tissue specimens of highly proliferative GEP-NEC or GEP-NEN located in the stomach and colon. In contrast, XIAP overexpression was associated with advanced tumor stages. Knockdown of survivin and XIAP markedly reduced cell proliferation and tumor growth. In vitro, YM155 induced apoptotic cell death accompanied by a reduction in cell proliferation and inhibited GEP-NEC xenograft growth. Taken together, our data provide evidence for a biological relevance of these IAPs in GEP-NEN and support a potential role of survivin as therapeutic target especially in the subgroup of aggressive GEP-NEC.

Topics: Animals; Antineoplastic Agents; Apoptosis; Biomarkers, Tumor; Carcinoma, Neuroendocrine; Cell Line, Tumor; Cell Proliferation; Comparative Genomic Hybridization; DNA Copy Number Variations; Dose-Response Relationship, Drug; Female; Gene Dosage; Gene Expression Regulation, Neoplastic; Humans; Imidazoles; Immunohistochemistry; Inhibitor of Apoptosis Proteins; Intestinal Neoplasms; Male; Masoprocol; Mice, Inbred NOD; Mice, SCID; Molecular Targeted Therapy; Naphthoquinones; Oligonucleotide Array Sequence Analysis; Pancreatic Neoplasms; Retrospective Studies; RNA Interference; Signal Transduction; Stomach Neoplasms; Survivin; Time Factors; Transfection; Tumor Burden; X-Linked Inhibitor of Apoptosis Protein; Xenograft Model Antitumor Assays

The effects of two naphthoquinones, juglone and plumbagin, and an isocoumarin, hydrangenol, on intestinal carcinogenesis in rats were examined by dietary exposure during the initiation phase. Starting at 5 weeks of age, male F344 rats were fed the diets containing either of the test chemicals at a concentration of 200 ppm or the control diet without the compounds. At 6 weeks of age, all animals were treated with s.c. injections of azoxymethane (AOM) (15 mg/kg body weight, once weekly for 3 weeks) or saline alone. Animals fed experimental diets were changed to the control diet 1 week after the last carcinogen treatment. Animals given plumbagin together with the carcinogen had a lower incidence (41%) and smaller multiplicity (0.48 +/- 0.62) of tumors in the entire intestine compared with those exposed to carcinogen alone (68% and 1.04 +/- 0.62) (P < 0.05 and < 0.01, respectively). The incidence and multiplicity of tumors in the small intestine (7% and 0.07 +/- 0.25) and the multiplicity of tumors in the entire intestine (0.60 +/- 0.76) of animals treated with juglone and the carcinogen were significantly less than those of animals treated with carcinogen alone (P < 0.05 in each). Hydrangenol tended to decrease the incidence and the multiplicity of tumors in the entire intestine induced by AOM, but the effect was not statistically significant. The present data suggest that the naphthoquinones, juglone and plumbagin, could be promising chemopreventive agents for human intestinal neoplasia.

Topics: Animals; Antineoplastic Agents, Phytogenic; Azo Compounds; Benzopyrans; Colonic Neoplasms; Coumarins; Diet; Intestinal Neoplasms; Isocoumarins; Male; Naphthoquinones; Rats; Rats, Inbred F344

Modifying effects of a fungal product, flavoglaucin, and four plant-derived chemicals, shikonin, gingerol, oleanolic acid and paeoniflorin, on intestinal carcinogenesis were examined in a rat model using azoxymethane (AOM). A total of 280 male F344 rats, 6 weeks old, were divided into 12 groups. Group 1 (30 rats) was given two subcutaneous injections of 15 mg/kg of AOM at the start of the experiment. Groups 2 (30 rats), 3 (20 rats), 4 (20 rats), 5 (30 rats) and 6 (30 rats) received a test chemical (flavoglaucin, shikonin, gingerol, oleanolic acid or paeoniflorin, respectively) in the diet at a concentration of 0.02% for 3 weeks, during which time AOM was applied, and then kept on basal diet until the end of experiment (one year). Groups 7-11 (each 20 rats) were given a test chemical corresponding to Groups 2-6, respectively. Group 12 (20 rats) served as a control. The incidence and average number of intestinal tumors in Group 2 (47%, 0.57 +/- 0.68) were significantly less than in Group 1 (74%, 1.07 +/- 0.87) (P < 0.05, respectively). Multiplicity of intestinal neoplasms of Group 3 (0.55 +/- 0.60) or 4 (0.47 +/- 0.51) was also significantly smaller than that of Group 1 (P < 0.05 and P < 0.01, respectively). These results suggest that flavoglaucin, shikonin and gingerol might be promising chemopreventive agents for intestinal neoplasia.

Topics: Animals; Antineoplastic Agents, Phytogenic; Azoxymethane; Benzoates; Bridged-Ring Compounds; Catechols; Drug Screening Assays, Antitumor; Fatty Alcohols; Gentisates; Glucosides; Intestinal Neoplasms; Male; Monoterpenes; Mutagens; Naphthoquinones; Oleanolic Acid; Rats; Rats, Inbred F344