an-207 and Ovarian-Neoplasms

Targeted chemotherapy is a modern approach aimed at increasing the efficacy of systemic chemotherapy and reducing its side effects. The peptide receptors expressed primarily on cancerous cells can serve as targets for a selective destruction of malignant tumors. Binding sites for LHRH (now known in genome and microarray databases as GNRH1), were found on 52% of human breast cancers, about 80% of human ovarian and endometrial cancers, and 86% of human prostatic carcinoma specimens. Because LHRH receptors are not expressed on most normal tissues, they represent a specific target for cancer chemotherapy with antineoplastic agents linked to an LHRH vector molecule. To test the efficacy of targeted chemotherapy based on LHRH analogs, we recently developed a cytotoxic analog of LHRH, designated AN-152, which consists of [D-Lys6]LHRH covalently linked to one of the most widely used chemotherapeutic agents, doxorubicin (DOX). In addition, we designed and synthesized a highly active derivative of DOX, 2-pyrrolino-DOX (AN-201), which is 500-1000 times more potent than DOX in vitro. AN-201 is active against tumors resistant to DOX, and noncardiotoxic. As in the case of DOX, AN-201 was coupled to carrier peptide [D-Lys6]LHRH to form a superactive targeted cytotoxic LHRH analog, AN-207. Both AN-152 and AN-207 can effectively inhibit the growth of LHRH receptor-positive human breast, ovarian, endometrial, and prostate cancers xenografted into nude mice. DOX-containing cytotoxic LHRH analog AN-152 is scheduled for clinical phase I/IIa trials in patients with advanced ovarian and breast cancers in 2005.

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Doxorubicin; Endometrial Neoplasms; Epithelial Cells; Female; Gonadotropin-Releasing Hormone; Humans; Male; Ovarian Neoplasms; Prostatic Neoplasms; Pyrroles; Receptors, LHRH

The receptors for luteinizing hormone-releasing hormone (LHRH) are found in 80% of human ovarian carcinomas. These receptors can be used for targeted chemotherapy with cytotoxic analogs of LHRH, such as AN-207, consisting of 2-pyrrolinodoxorubicin (AN-201) linked to [D-Lys ]LHRH. We investigated the effects of AN-207 and AN-201 on the growth of LHRH receptor-positive ES-2 human ovarian cancers. The effects of the treatment on mRNA and protein levels of human epidermal growth factor (EGF) receptors (EGFR and HER-2) in ovarian tumors were determined by RT-PCR and immunoblotting. In Experiment 1, nude mice bearing ES-2 ovarian tumors were injected i.v. with 250 nmol/kg doses of AN-207, AN-201, the carrier [D-Lys ]LHRH, an unconjugated mixture of AN-201 and [D-Lys ]LHRH or vehicle. AN-207 caused a significant ( <0.01) 59.5% inhibition in tumor growth while its components were ineffective. In Experiment 2, mice with large ES-2 tumors were treated with AN-207 or AN-201 at 250 nmol/kg. Again, AN-207, but not AN-201, inhibited tumor growth. In Experiment 3, the site of action of AN-207 was investigated. The blockade of LHRH receptors with Cetrorelix partially suppressed the antitumor effect of AN-207. Treatment with AN-207 significantly ( <0.01) decreased the expression of mRNA for EGFR, and HER-2 by 27 and 34%, respectively, as compared to controls and reduced the receptor protein levels of EGFR and HER-2 by 35 and 36%, respectively ( <0.05). The results indicate that cytotoxic LHRH analog AN-207 could be considered for chemotherapy of ovarian cancers expressing LHRH receptors.

Topics: Animals; Antineoplastic Agents; Doxorubicin; Drug Evaluation, Preclinical; ErbB Receptors; Female; Gonadotropin-Releasing Hormone; Humans; Mice; Mice, Nude; Neoplasm Transplantation; Ovarian Neoplasms; Pyrroles; Receptor, ErbB-2; Receptors, LHRH; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Treatment Outcome; Tumor Cells, Cultured

Targeting of cytotoxic agents represents a modern approach to the treatment of various cancers, that improves the efficacy and reduces peripheral toxicity. Recently we developed a powerful cytotoxic analog of luteinizing hormone-releasing hormone (LHRH), AN-207, designed to be targeted to tumors that express LHRH receptors. This analog consists of the superactive derivative of doxorubicin (DOX), 2-pyrrolino-DOX (AN-201), linked to [D-Lys6]LHRH carrier. In the present study we investigated the cytocidal effects of AN-207 and AN-201 on the LHRH receptor-positive ES-2 ovarian cancer cells. The targeting of AN-207 to ES-2 cells in the presence of LHRH receptor-negative UCI-107 ovarian cancer cells was also evaluated by semi-quantitative polymerase chain reaction (PCR) amplification of microsatellite markers. Ligand competition assays showed a single class of high-affinity and low-capacity binding sites in ES-2 cells with a mean dissociation constant (KD) of 3.93 +/- 0.1 nM and a mean maximal binding capacity (Bmax) of 271 +/- 26.1 fmol/mg membrane protein. Kinetic assays indicated that AN-207 caused cell death in a concentration- and time-dependent manner in ES-2 cells, but not in UCI-107 cells, while the kinetics of cytotoxic effects of AN-201 were similar in both cell lines. To investigate targeting, ES-2 cells were co-cultured with UCI-107 cells, treated with 10 nM AN-207 or AN-201 for different times and then cultured for 48 h in the absence of cytotoxic agents. Genomic DNA was extracted for microsatellite analyses using different markers. Semi-quantitative analyses of the intensity of the alleles that correspond to each cell line indicated that AN-207 was selectively targeted to ES-2 cells, while AN-201 showed no selectivity for either cell line. These results extend our previous findings that AN-207 can be targeted to ovarian cancers and other tumors that express receptors for LHRH. Cytotoxic analogs of LHRH, such as AN-207, should be considered for treatment of LHRH receptor-positive tumors.

Topics: Antineoplastic Agents; Coculture Techniques; Doxorubicin; Drug Delivery Systems; Female; Gonadotropin-Releasing Hormone; Humans; Microsatellite Repeats; Middle Aged; Ovarian Neoplasms; Receptors, LHRH; Toxicity Tests; Tumor Cells, Cultured

The aim of the study was to investigate the effects of the cytotoxic analog of luteinizing hormone-releasing hormone AN-207 on the growth of the OV-1063 human epithelial ovarian cancers, which express luteinizing hormone-releasing hormone receptor. AN-207 consists of doxorubicin derivative 2-pyrrolinodoxorubicin (AN-201) linked with the carrier [D-lysine6 ]luteinizing hormone-releasing hormone.. Female nude mice bearing xenografts of OV-1063 ovarian cancers were treated with analog AN-207, cytotoxic radical AN-201, or agonist [D-lysine6 ]luteinizing hormone-releasing hormone. The levels and expression of messenger ribonucleic acid of receptors for luteinizing hormone-releasing hormone and epidermal growth factor were evaluated.. The growth of OV-1063 tumor was significantly inhibited by 3 to 5 nmol AN- 207 but not by [D-lysine6 ]luteinizing hormone-releasing hormone. Cytotoxic radical AN-201 was toxic at these doses. After treatment with AN-207 receptors for luteinizing hormone-releasing hormone were not detectable, epidermal growth factor receptor levels declined, and expressions of their respective messenger ribonucleic acids were decreased.. Targeted cytotoxic luteinizing hormone-releasing hormone analog AN-207 is less toxic than equimolar doses of its radical 2-pyrrolinodoxorubicin and effectively inhibits ovarian tumor growth. Targeted chemotherapy may improve management of ovarian cancer.

Topics: Animals; Antineoplastic Agents; Cell Division; Cystadenocarcinoma, Papillary; Doxorubicin; ErbB Receptors; Female; Glyceraldehyde-3-Phosphate Dehydrogenases; Gonadotropin-Releasing Hormone; Humans; Mice; Mice, Nude; Middle Aged; Neoplasm Transplantation; Ovarian Neoplasms; Receptors, LHRH; RNA, Messenger; Tumor Cells, Cultured