fenretinide and Uterine-Neoplasms

Although tamoxifen appears to markedly reduce breast cancer risk in women with a prior diagnosis of atypical hyperplasia or in situ carcinoma, it is not clear what other groups of women receive substantial benefit. Major breast chemoprevention priorities are to (1) develop new agents that (a) have fewer side effects, (b) are effective in ER--as well as tamoxifen-resistant precancerous tissue, and (c) are compatible with hormone therapy; and (2) develop efficient clinical strategies including prognostic and predictive morphologic and molecular biomarkers. Breast tissue may be repeatedly sampled for evidence of intraepithelial neoplasia by fine needle aspiration, ductal lavage, or needle biopsy to select candidates at highest short-term risk as well as to monitor response in small proof of principle studies prior to a large cancer incidence trial. Molecular marker expression may also be used to select a cohort most likely to respond to a particular agent. A large number of new agents are attractive as potential prevention agents and some are already in clinical prevention testing. Compounds which should be effective in ER + precancerous tissue but may have a better side-effect profile include new selective estrogen receptor modulators which lack uterine estrogen agonist activity, isoflavones, aromatase inactivators/inhibitors for postmenopausal women, and gonadotropin-releasing hormone regimens for premenopausal women. Retinoids, rexinoids, and deltanoids may be efficacious in ER+ tissue resistant to tamoxifen. Agents which should theoretically have activity in ER- or ER+ precancerous tissue include polyamine synthesis inhibitors, tyrosine kinase inhibitors, combined demethylating agents and histone deacetylase inhibitors, as well as metalloprotease and angiogenesis inhibitors. Sample Phase I and Phase II clinical trial designs are reviewed using modulation of molecular markers and breast intraepithelial neoplasia as the major endpoints.

Topics: Aneuploidy; Angiogenesis Inhibitors; Anticarcinogenic Agents; Apoptosis; Aromatase Inhibitors; Breast Neoplasms; Carcinoma in Situ; Clinical Trials, Phase II as Topic; Cyclooxygenase Inhibitors; Disease Progression; Eflornithine; Endpoint Determination; Enzyme Inhibitors; Estrogens; Female; Fenretinide; Gonadotropin-Releasing Hormone; Humans; Hyperplasia; Isoflavones; Neoplasm Proteins; Neoplasms, Hormone-Dependent; Phenotype; Piperidines; Polyamines; Precancerous Conditions; Protein-Tyrosine Kinases; Receptors, Estrogen; Selective Estrogen Receptor Modulators; Tamoxifen; Thiophenes; Uterine Neoplasms

This study examined the effects of the chemopreventive agents 4-(N-hydroxyphenyl)retinamide (4-HPR) and alpha-difluoromethylornithine (DFMO) on leiomyoma growth.. Primary cultures of human uterine leiomyomas and matched normal myometrium were established from hysterectomy specimens. After treatment with 4-HPR, DFMO, or the combination 4-HPR plus DFMO, cell growth was analyzed. Apoptosis was quantified with the use of a flow cytometric terminal deoxynucleotidyl transferase-mediated fluorescein-deoxyuridine-triphosphate nick-end labeling assay. Protein extracts were analyzed with Western blot for p53, p21, and p16.. 4-HPR and DFMO inhibited the growth and induced apoptosis of leiomyoma cells, but not matched normal myometrial cells. Both 4-HPR and DFMO caused cells to accumulate at G0/G1, with a corresponding decrease in the S-phase fraction. Both agents also caused the induction of p53, p21, and p16.. The chemopreventive agents 4-HPR and DFMO inhibit leiomyoma cell growth in vitro and induce apoptosis, which implies that retinoids and polyamines are important regulators of leiomyoma growth.

Topics: Antineoplastic Agents; Apoptosis; Cell Division; Cyclin-Dependent Kinase Inhibitor p16; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; Eflornithine; Female; Fenretinide; Humans; Leiomyoma; Tumor Cells, Cultured; Tumor Suppressor Protein p53; Uterine Neoplasms

The effect of the chemopreventive synthetic retinoid N-(4-hydroxyphenyl)-retinamide (4-HPR) on aromatase activity and expression was examined. 4-HPR caused a dose-dependent inhibition of aromatase activity in microsomes isolated from JEG-3 human placental carcinoma cells. The kinetics of inhibition were analysed by double-reciprocal plot. The Km of the substrate increased and the Vmax of the reaction decreased in the presence of 4-HPR, indicating that enzyme inhibition involved both competition for the substrate-binding site and non-competitive mechanisms. To determine whether 4-HPR would also inhibit aromatase activity in intact cells, MCF-7 human breast cancer cells were incubated with or without cAMP in the presence of 4-HPR. 4-HPR inhibited both basal and cAMP-induced aromatase activity in intact MCF-7 cells. The induction of aromatase mRNA expression in MCF-7 cells by cAMP was inhibited in cells treated with 4-HPR. These results indicate that 4-HPR inhibits both the enzymatic activity and expression of aromatase. These activities may play an important role in the known chemopreventive effect of 4-HPR towards breast cancer.

Topics: Anticarcinogenic Agents; Aromatase; Aromatase Inhibitors; Breast Neoplasms; Choriocarcinoma; Enzyme Induction; Female; Fenretinide; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; Microsomes; Pregnancy; RNA, Messenger; RNA, Neoplasm; Tumor Cells, Cultured; Uterine Neoplasms