Cancer chemotherapy and pharmacology
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Cancer Chemother. Pharmacol. · Jan 1994
Preclinical pharmacology of bizelesin, a potent bifunctional analog of the DNA-binding antibiotic CC-1065.
Bizelesin (NSC-615291), a potent, bifunctional analog of the cyclopropylpyrroloindole antitumor antibiotics CC-1065 and adozelesin, has been selected by the National Cancer Institute for evaluation as a potential chemotherapeutic agent. All three compounds bind to and alkylate DNA at the N-3 position of adenine in a sequence-selective manner. Bizelesin is unique among the analogs with bifunctional alkylating capability due to two chloromethyl moieties that are converted to the cyclopropyl alkylating species that interact with DNA. ⋯ Following i.v. administration of bizelesin (15 micrograms/kg) to male CD2F1 mice, the plasma elimination of cytotoxic activity determined with the bioassay was described by a two compartment open model; the alpha-phase (t1/2 alpha) and beta-phase (t1/2 beta) half-lives, steady-state volume of distribution (VSS), and total body clearance (ClTB) were 3.5 min, 7.3 h, 7,641 ml/kg, and 16.3 ml min-1 kg-1, respectively. The systemic drug exposure following i.p. administration was at least 10 times lower than that resulting from i.v. infusion. Following i.v. or i.p. administration the recovery of material in urine was < 0.1% of the delivered dose.
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Cancer Chemother. Pharmacol. · Jan 1993
Treatment of subcutaneous and intracranial brain tumor xenografts with O6-benzylguanine and 1,3-bis(2-chloroethyl)-1-nitrosourea.
O6-Alkylguanine-DNA alkyltransferase (AT) is a cellular protein that protects cells from the cytotoxic effects of nitrosoureas by repairing alkyl lesions at the O6 position of guanine. We have studied the ability of O6-benzylguanine to deplete AT activity in brain tumor xenografts and thereby increase the sensitivity of these tumors to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). In toxicity studies, pretreatment of athymic mice with O6-benzylguanine increased the toxicity of BCNU significantly. ⋯ These studies suggest that O6-benzylguanine may be a useful adjuvant to nitrosourea therapy in human malignancies that exhibit a range of AT activities and that dose and timing are important variables in achieving therapeutic success. These data also indicate that therapeutic potentiation of BCNU by O6-benzylguanine can be achieved in i.c. tumors. As a result, this approach may be useful in the treatment of neoplasms of the central nervous system.
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Cancer Chemother. Pharmacol. · Jan 1993
Cisplatin-induced neuropathy in mature rats: effects of the melanocortin-derived peptide ORG 2766.
A major side effect of cisplatin treatment is peripheral neuropathy. In the past few years we have provided evidence that the ACTH4-9 analogue ORG 2766 provides protection against this neuropathy in rats and man. In this study we investigated the development of a cisplatin-induced neuropathy and the protective and therapeutic actions of ORG 2766 in mature rats. ⋯ ORG 2766 did not enhance the rate of recovery. In the young adult rats neither ORG 2766 administration nor restricted weight gain significantly influenced either the motor or the sensory nerve conduction velocity. These results validate the animal model of cisplatin-induced neuropathy.
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Cancer Chemother. Pharmacol. · Jan 1992
Antitumor activity of treosulfan against human breast carcinomas.
Treosulfan (L-threitol-1,4-bismethanesulfonate, Ovastat) is a bifunctional alkylating agent that shows a formal structural similarity to busulfan and is applied clinically to patients suffering from ovarian cancer. The present study demonstrated the pronounced antitumor activity of this drug against three of five human breast carcinomas xenografted to athymic mice. It was shown that treosulfan is capable of inducing irreversible and complete remission of the heterotransplanted human breast carcinomas MDA-MB-436 and MX-1 within 14 days after drug application and of effecting growth inhibition by more than 90% in the MDA-MB-435S xenograft. ⋯ The FM 2 breast carcinoma, finally, was the only xenograft whose growth was not influenced by treosulfan at doses up to that which was lethal to 50% of the treated mice (LD50 value). These results confirm that treosulfan is effective against human breast carcinomas. Because of this activity as well as the known low toxicity and good clinical compatibility of treosulfan, it should be considered for introduction into nonendocrine chemotherapeutic regimens against human breast carcinomas and investigation in clinical trials.
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Cancer Chemother. Pharmacol. · Jan 1990
Effect of ribonucleotide reductase inhibitors on the growth of human colon carcinoma HT-29 cells in culture.
The effects of ribonucleotide reductase inhibitors on the growth of the human colon carcinoma cell line HT-29 were examined. Inhibitors were chosen for these studies that were specifically directed at each of the subunits of ribonucleotide reductase. The concentrations of drugs required to inhibit the growth of HT-29 cells by 50% (IC50) for hydroxyurea, 2,3-dihydro-lH-pyrazole-[2,3a]imidazole (IMPY), and 4-methyl-5-amino-l-formyl-isoquinoline thiosemicarbazone (MAIQ) were 206, 996, and 3.2 microM, respectively. ⋯ The addition of 8-aminoguanosine to protect deoxyguanosine from phosphorolysis by purine nucleoside phosphorylase did not increase the toxicity of deoxyguanosine in HT-29 cells. The combination of MAIQ or IMPY and deoxyadenosine/EHNA gave strong synergistic inhibition of HT-29 cell growth. The results of these studies indicate that ribonucleotide reductase inhibitors effectively block the growth of human colon carcinoma HT-29 cells and that combinations of inhibitors directed at the individual subunits of reductase result in synergistic inhibition of HT-29 cell growth in culture.