dolastatin-10 and Lung-Neoplasms

Topics: Aged; Antineoplastic Agents; Carcinoma, Non-Small-Cell Lung; Depsipeptides; Dose-Response Relationship, Drug; Female; Follow-Up Studies; Humans; Infusions, Intravenous; Lung Neoplasms; Male; Middle Aged; Oligopeptides; Severity of Illness Index; Survival Rate; Treatment Outcome

Malevamide D (1), a highly cytotoxic peptide ester, and the known compound curacin D (5) were isolated from a Hawaiian sample of Symploca hydnoides. The structure of 1 was elucidated by spectroscopic analysis including NMR and high-resolution MS/MS. Partial stereochemical assignments of 1 were made by chiral HPLC analysis of acid and base hydrolysates. Malevamide D (1) demonstrated toxicity against P-388, A-549, HT-29, and MEL-28 cell lines in the subnanomolar range, while curacin D (5) was weakly cytotoxic. Malevamide D (1) is closely related to isodolastatin H (2), which was previously isolated in low yield from the sea hare Dolabella auricularia. A second Hawaiian sample of S. hydnoides yielded curacin D (5) along with the known dolastatin-10 analogue symplostatin-1 (3).

Topics: Animals; Antineoplastic Agents, Phytogenic; Chromatography, High Pressure Liquid; Colonic Neoplasms; Cyanobacteria; Depsipeptides; Drug Screening Assays, Antitumor; Hawaii; Hydrolysis; Inhibitory Concentration 50; Leukemia P388; Lung Neoplasms; Melanoma; Mice; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Oligopeptides; Stereoisomerism; Thiazoles; Tumor Cells, Cultured

Dolastatin 10 is a natural cytotoxic peptide which acts through the inhibition of microtubule assembly. Studies have suggested that such agents can induce apoptosis in association with bcl-2 phosphorylation. Since bcl-2 overexpression is common in small-cell lung cancer (SCLC), we evaluated the activity of dolastatin 10 in SCLC cell lines and xenografts.. In vitro growth inhibition was evaluated with a standardized MTT assay and apoptosis with fluorescent microscopy and a TUNEL assay. Immunoblot analysis and phosphatase digestion were used to determine bcl-2 modification. In vivo activity was evaluated in subcutaneous and metastatic SCLC xenograft models in SCID mice.. Dolastatin 10 had growth inhibitory activity against four SCLC cell lines (NCI-H69, -H82, -H446, -H510) with IC50 values ranging from 0.032 to 0.184 nM. All four cell lines exhibited evidence of apoptosis after 48 h of exposure to 1.3 nM dolastatin 10. Immunoblot analysis revealed that 1.3 nM dolastatin 10 altered the electrophoretic mobility of bcl-2 in NCI-H69 and -H510 cells within 16 h of treatment. Incubation of protein extract from dolastatin 10-treated NCI-H69 and -H510 cells with calcineurin resulted in the disappearance of the altered mobility species, suggesting dolastatin 10-induced bcl-2 phosphorylation. In in vivo studies, 450 microg/kg of dolastatin 10 IV x 2 given after intravenous injection of NCI-H446 cells completely inhibited tumor formation. In established subcutaneous NCI-H446 xenografts, 450 microg/kg of dolastatin 10 IV induced apoptosis in the majority of tumor cells within 96 h, resulting in a log10 cell kill of 5.2 and an increase in median survival from 42 to 91 days.. These findings suggest that dolastatin 10 has potent activity against SCLC and that the modulation of apoptotic pathways deserves further evaluation as an anticancer strategy.

Topics: Animals; Antineoplastic Agents; Apoptosis; Carcinoma, Small Cell; Depsipeptides; Female; Humans; Lung Neoplasms; Mice; Mice, SCID; Neoplasm Transplantation; Oligopeptides; Phosphorylation; Proto-Oncogene Proteins c-bcl-2; Transplantation, Heterologous; Tumor Cells, Cultured

Dolastatin 10, a pentapeptide isolated from the marine mollusk Dolabella auricularia, has antitumor activity. TZT-1027, a dolastatin 10 derivative, is a newly synthesized antitumor compound. We evaluated its antitumor activity against a variety of transplantable tumors in mice. Intermittent injections of TZT-1027 were more effective than single or repeated injections in mice with P388 leukemia and B16 melanoma. Consequently, TZT-1027 shows schedule dependency. TZT-1027 was effective against P388 leukemia not only when administered i.p., but also when given i.v. However, although TZT-1027 given i.v. was active against murine solid tumors, TZT-1027 administered i.p. was ineffective against all the tumors tested with the exception of colon 26 adenocarcinoma. The i.v. injection of TZT-1027 at a dose of 2.0 mg/kg remarkably inhibited the growth of three murine solid tumors; colon 26 adenocarcinoma, B16 melanoma and M5076 sarcoma, with T/C values of less than 6%. The antitumor activities of TZT-1027 against these tumors were superior or comparable to those of the reference agents; dolastatin 10, cisplatin, vincristine, 5-fluorouracil (5-FU) and E7010. In experiments with drug-resistant P388 leukemia, TZT-1027 showed good activity against cisplatin-resistant P388 and moderate activity against vincristine- and 5-fluorouracil-resistant P388, but no activity against adriamycin-resistant P388. TZT-1027 was also effective against human xenografts, that is, tumor regression was observed in mice bearing MX-1 breast and LX-1 lung carcinomas. TZT-1027 at 10 microM almost completely inhibited the assembly of porcine brain microtubules. Therefore, its mechanism of antitumor action seems to be, at least in part, ascribable to the inhibition of microtubule assembly. Because of its good preclinical activity, TZT-1027 has been entered into phase I clinical trials.

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Cell Division; Cisplatin; Crosses, Genetic; Depsipeptides; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Screening Assays, Antitumor; Female; Humans; Leukemia P388; Lung Neoplasms; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred DBA; Mice, Nude; Mollusca; Neoplasms, Experimental; Oligopeptides; Transplantation, Heterologous