dolastatin-10 and bryostatin-1

Marine antitumor drugs have been the research focus in the world. Recently, advancement has been made in the investigation of six types of compounds including bryostatin-1, ecteinascidin-743, dolastatin, didemnin B, psammaplin and halichondrin B. In this review, we summarized the recent research progress of the above mentioned marine antitumor drugs and their derivatives. Also, the development tendency of marine antitumor drugs was discussed.

Topics: Animals; Antineoplastic Agents; Apoptosis; Biological Products; Bryostatins; Cell Line, Tumor; Depsipeptides; Dioxoles; Disulfides; Ethers, Cyclic; Humans; Macrolides; Marine Biology; Neoplasms; Tetrahydroisoquinolines; Trabectedin; Tyrosine

Topics: Animals; Antineoplastic Agents, Alkylating; Antineoplastic Agents, Phytogenic; Bryostatins; Clinical Trials, Phase I as Topic; Depsipeptides; Dioxoles; Drug Screening Assays, Antitumor; Humans; Isoquinolines; Lactones; Macrolides; Marine Biology; Neoplasms; Oligopeptides; Peptides, Cyclic; Tetrahydroisoquinolines; Trabectedin

Previous studies have shown that bryostatin 1 induces a decrease in the expression of the antiapoptotic protooncogene Bcl-2 in the human acute lymphoblastic leukemia (ALL) cell line Reh. This down-regulation has been shown to reduce drug resistance of the Reh cells to anti-tubulin polymerization agents. In the present study we investigated the effect of bryostatin 1 alone and in combination with novel anti-tubulin agents (dolastatin 10 and auristatin PE) and the chemotherapeutic vincristine on the inhibitor of apoptosis protein cIAP-1. Cells were cultured with bryostatin 1 (1 nM), dolastatin 10 (0.1 ng/ml), auristatin PE (0.1 ng/ml), or vincristine (0.5 ng/ml) alone or the combination of these anti-tubulins with bryostatin 1. Western blots were conducted to assess the effects of the above agents on cIAP-1 protein level. Flow-cytometric analysis [7-amino-actinomycin D (7AAD)] was conducted to assess apoptosis as well as staining for morphology using tetrachrome stain. Our results show that cIAP-1 is induced in a time-dependent fashion after bryostatin 1 exposure up to 72 h. However, upon treatment of cells with a combination of bryostatin 1 and dolastatin 10 or auristatin PE, the induction of cIAP-1 was abolished, leading to a significant increase in apoptosis. The initial 24- and 48-h reduction in cIAP-1 protein level recorded in the bryostatin 1 and vincristine combination recovered to control levels by 72 h. We believe that this phenomenon is responsible for the reduced apoptosis recorded in this combination. Results of this study should prove useful in guiding the clinical application of these novel agents in the treatment of ALL.

Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Bryostatins; Depsipeptides; Down-Regulation; Flow Cytometry; Humans; Inhibitor of Apoptosis Proteins; Lactones; Macrolides; Oligopeptides; Precursor B-Cell Lymphoblastic Leukemia-Lymphoma; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Proteins; Proto-Oncogene Proteins c-bcl-2; Tumor Cells, Cultured; Vincristine

We studied the antitumor effects of dolastatin 10, its structural modification, auristatin PE (TZT-1027), and vincristine alone and in combination with bryostatin 1 on a human diffuse large cell lymphoma line (WSU-DLCL2) in vitro and in vivo. WSU-DLCL2 cells were cultured in RPMI 1640 at a concentration of 2 x 10(5)/ml using a 24-well plate. Agents were added to triplicate wells, and cell count, viability, mitosis and apoptosis were assessed. Dolastatin 10 showed no apparent inhibition of cell growth at concentrations less than 500 pg/ ml. Auristatin PE showed significant growth inhibition at concentrations as low as 10 pg/ml, while vincristine had a minimal effect at 50 pg/ml. Dolastatin 10, auristatin PE and vincristine-treated cultures, at 50 pg/ml, exhibited 11, 1.7; 45, 11.8%; and 39, 25% mitosis and apoptosis, respectively. In the WSU-DLCL2 SCID mouse xenograft model, the efficacy of these agents alone or in combination with bryostatin 1 was evaluated. Tumor growth inhibition (T/C), tumor growth delay (T-C) and log10 kill for dolastatin 10, auristatin PE, vincristine and bryostatin 1 were 30%, 14 days and 1.4; 0.0%, 55 days and 5.5; 29.6%, 16 days and 1.6; and 39%, 7 days and 0.7, respectively. When given in combination, two out of five mice treated with auristatin PE + bryostatin 1 were free of tumors for 150 days and were considered cured. Dolastatin 10 + bryostatin 1 and vincristine + bryostatin 1 combinations were highly active but no cure was observed. We conclude that: (i) auristatin PE is more effective in this model than dolastatin 10, vincristine or bryostatin 1, (ii) auristatin PE can be administered at a concentration 10 times greater than dolastatin 10, and (iii) there is a synergistic effect between these agents and bryostatin 1, which is more apparent in the bryostatin 1 + auristatin PE combination. The use of these agents should be further explored clinically in the treatment of lymphoma.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Bryostatins; Depsipeptides; Drug Synergism; Humans; Lactones; Lymphoma, Large B-Cell, Diffuse; Macrolides; Mice; Mice, Inbred ICR; Oligopeptides; Time Factors; Tumor Cells, Cultured; Vincristine

We tested the activity of dolastatin 10 (a natural product derived from the shell-less marine mollusk, Dolabella auricularia, a sea hare) and its structural modification, auristatin PE, alone and in combination with bryostatin 1 (a protein kinase C activator derived from the marine bryozoan Bugula neritina) on a human B-cell chronic lymphocytic leukemia cell line (WSU-CLL) and in a severe combined immune deficient (SCID) mouse xenograft model bearing this cell line. WSU-CLL cells were cultured in RPMI 1640 at a concentration of 2 x 10(5)/ml using a 24-well plate. Agents were added to triplicate wells, and cell count, viability, mitosis, and apoptosis were assessed after 24 h of incubation at 37 degrees C. Results showed that dolastatin 10 had no apparent inhibition of cell growth at concentrations less than 500 pg/ml. Auristatin PE, on the other hand, showed significant growth inhibition at concentrations as low as 50 pg/ml. Auristatin PE-treated cultures, at this concentration, exhibited 27 and 4.5% mitosis and apoptosis, respectively. Dolastatin 10, at the same concentration, did not exert any effect and was comparable with that of control cultures. In the WSU-CLL-SCID mouse xenograft model, the efficacy of these agents alone and in combination with bryostatin 1 was evaluated. Tumor growth inhibition (T/C), tumor growth delay (T-C), and log10 kill for dolastatin 10, auristatin PE, and bryostatin 1 were 14%, 25 days, and 1.98; 2%, 25 days, and 1.98; 19%, 13 days, and 1.03, respectively. Auristatin-PE produced cure in three of five mice, whereas dolastatin 10 showed activity but no cures. When given in combination, auristatin PE + bryostatin 1-treated animals were all free of tumors (five of five) for 150 days and were considered cured. Dolastatin 10 + bryostatin 1-treated animals produced cure in only two of five mice. We conclude that: (a) auristatin-PE is more effective in this model than dolastatin 10; (b) auristatin PE can be administered at a concentration 10 times greater than dolastatin 10; (c) there is a synergetic effect between these agents and bryostatin 1, which is more apparent in the bryostatin 1 + auristatin PE combination. The use of these agents should be explored clinically in the treatment of CLL.

Topics: Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Bryostatins; Cell Count; Depsipeptides; Drug Screening Assays, Antitumor; Female; Humans; Lactones; Leukemia, Lymphocytic, Chronic, B-Cell; Macrolides; Mice; Mice, SCID; Mitosis; Oligopeptides; Subrenal Capsule Assay; Survival Analysis; Treatment Outcome; Tumor Cells, Cultured

The effects of dolastatin 10 (Dol10) and dolastatin 15 (Dol15) alone, and after treatment with bryostatin 1 (Bryo1), on human diffuse large cell lymphoma cell line (WSU-DLCL2) were studied. At a concentration of 1.0 ng/ml Dol10 and Dol15 showed significant growth inhibition (p < 0.05). This inhibition was intensified when the cells were pretreated for 24 h with 200 nM Bryo1. Bryo1, Dol10 and Dol15 induced apoptosis which was seen on morphological examination, by flow cytometry and DNA fragmentation on agarose gel electrophoresis. Cells pretreated with Bryo1 and then exposed to Dol10 showed an increase in apoptosis compared with cells that were treated with the Dol10, Dol15 alone. Immunocytochemistry revealed that WSU-DLCL2 cells express the bcl-2 oncoprotein constitutively. bcl-2 expression was decreased when cells were treated with Bryo1, Dol10 or Dol15 and abolished with the Bryo1/Dol10 combination. WSU-DLCL2 cells were negative for p53 protein expression, upon treatment with Bryo1 or Dol10, the expression of p53 was weak and moderate with the Bryo1/Dol10 combination. The inverse correlation between bcl-2 and p53 oncoprotein expression seems to be related to induction of apoptosis in this lymphoma cell line.

Topics: Antineoplastic Agents; Apoptosis; Bryostatins; Cell Division; Depsipeptides; DNA, Neoplasm; Electrophoresis, Agar Gel; Flow Cytometry; Humans; Immunohistochemistry; Lactones; Lymphoma, Large B-Cell, Diffuse; Macrolides; Oligopeptides; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Tumor Cells, Cultured; Tumor Suppressor Protein p53

The effects of two natural peptides, dolastatin 10 and dolastatin 15, on growth and differentiation of hematopoietic cells were studied using freshly explanted leukemia cells and continuous leukemia cell lines. The proliferation of several myeloid cell lines and of growth-factor-stimulated peripheral blood cells from patients with acute myeloid leukemia (AML) was efficiently inhibited by the two agents at concentrations between 1 and 0.01 nM. Growth inhibition was dose-dependent and reversible. Neither of the dolastatins exhibited significant cytotoxicity on dividing cells, nor did they interfere with the viability of resting cells. The 12-O-tetradecanoylphorbol 13-acetate or bryostatin I induced differentiation of AML cells was not affected by the dolastatins. Short-term exposure to the phorbol ester conferred reduced sensitivity of the cell line HL-60 to the antiproliferative effect of the drugs. Our data suggest that the dolastatins alone or in combination with other drugs could exert a role in the treatment of human myeloid leukemia.

Topics: Antineoplastic Agents; Bryostatins; Cell Differentiation; Cell Division; Depsipeptides; Humans; In Vitro Techniques; Lactones; Leukemia; Macrolides; Oligopeptides; Tetradecanoylphorbol Acetate; Tumor Cells, Cultured