Gonadotrophin-releasing hormone: physiological significance and relevance to cancer

Ovarian Function Suppression with the Gonadotrophin-Releasing Hormone (GnRH) Analogue Goserelin in Premenopausal Advanced Breast Cancer

Aims and background

Goserelin is a gonadotrophin-releasing hormone (GnRH) analogue that induces the suppression of gonadal steroidogenesis, and it could therefore be a medical alternative to irreversible surgical castration. We report the clinical and endocrine results from 40 goserelin-treated premenopausal patients with advanced breast cancer.

Methods

A depot formulation of the drug (3.6 mg s.c.) was administered fortnightly for the first 4 doses, and monthly thereafter. Gonadotrophins and estradiol (E2) levels were measured before and at specific times during the treatment.

Results

Objective responses were observed in 17 of the 38 evaluable patients (45%), six of whom achieved complete remission. The best responses were observed on soft tissues (65%). Castration E2 levels were achieved in all of the patients.

Conclusions

Our results confirm that goserelin is as effective as surgical oophorectomy in premenopausal advanced breast cancer.

LHRH-conjugated lytic peptides directly target prostate cancer cells

Prostate cancer is the second leading cause of cancer deaths among men. For patients with hormone-refractory disease, few treatments are available once the tumor has metastasized beyond the prostate. In the present study, two conjugated lytic peptide sequences (named JCHLHRH and JC21LHRH) were designed to target luteinizing hormone-releasing hormone receptors (LHRH-R). Our results indicate that human prostate cancer cell lines were sensitive to both LHRH-conjugated and non-conjugated lytic peptides, with IC(50) concentrations for LNCaP cells, 4.4 and 9.1μM; for DU-145 cells, 4.8 and 5.7μM; and for PC-3 cells, 4.4 and 8.2μM, respectively. JCHLHRH and JC21LHRH were nontoxic to normal primary human prostate epithelial cells or to bone marrow stromal cells in co-culture. There were morphological changes in PC-3 cells after 3h of exposure to either peptide; after 6h, there were significant reductions in cell numbers. Exposure of PC-3 cells for 24h to either JCHLHRH or JC21LHRH blocked their growth over 3 days. Since JCHLHRH and JC21LHRH have specificity for and anti-proliferative activity against tumor cells, and low toxicity for normal prostate cells, these peptides could serve as a new type of therapy for prostate cancer.