All-trans-retinoic acid (ATRA), the primary active metabolite of vitamin A, was examined for its antiestrogenic activity in rats using an in vivo uterotrophic assay. All rats were ovariectomized 2 weeks prior to receiving 5 mg/kg/day ATRA or 0.3 micro g/kg/day ethynyl estradiol (EE) subcutaneously once a day for 3 consecutive days. Rats were sacrificed 1, 3, 6, 12 or 24 h after the last treatment. EE increased uterine weight and the coinjection of ATRA with EE significantly suppressed this effect 3 and 24 h after treatment. mRNA expression was examined during this 24-h period and the mRNA expression levels of estrogen receptor alpha (ER alpha), retinoic acid receptor beta (RAR beta), retinoid X receptor gamma (RXR gamma) and cellular retinol-binding protein I (CRBP I) were found to have significantly increased in the ATRA+EE group compared with those in the EE group. This is the first report on the antiestrogenic activity of ATRA determined using an in vivo adult rat uterotrophic assay. The up-regulation of RAR or RXR mRNA expression level was probably responsible for the antiestrogenic activity of ATRA.
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http://dx.doi.org/10.1016/j.lfs.2006.11.026 | DOI Listing |
Breast Cancer Res
January 2025
Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL, 50153, USA.
Resistance to endocrine therapies remains a major clinical hurdle in breast cancer. Mutations to estrogen receptor alpha (ERα) arise after continued therapeutic pressure. Next generation selective estrogen receptor modulators and degraders/downregulators (SERMs and SERDs) show clinical efficacy, but responses are often non-durable.
View Article and Find Full Text PDFNat Commun
January 2025
Genor Biopharma Co., Ltd, Beijing, China.
Lerociclib (GB491), a highly selective oral CDK4/6 inhibitor, has displayed anti-tumor activity and differentiated safety and tolerability profile in previous ph1/2 clinical trials. The LEONARDA-1, a randomized, double-blind, phase III study, was conducted to evaluate the efficacy and safety of lerociclib in HR+/HER2- locally advanced or metastatic breast cancer patients, who had relapsed or progressed on prior endocrine therapy. A total of 275 patients were randomized at 1:1 ratio to receive lerociclib (137 patients, 150 mg twice daily) or placebo (138 patients) plus fulvestrant.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Obstetrics and Gynecology, Shiga University of Medical Science, 520-2192/Seta Tsukinowa-cho, Otsu, Shiga, Japan.
Tamoxifen, a common adjuvant therapy for hormone receptor-positive breast cancer, is associated with an increased risk of endometrial pathologies, such as hyperplasia, polyps, and carcinoma. This study investigates rapamycin, an mTOR inhibitor, as a potential novel strategy for preventing tamoxifen-induced endometrial proliferation. This in vitro study utilised endometrial stromal cells isolated from infertile women.
View Article and Find Full Text PDFIUBMB Life
January 2025
Department of General Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China.
Tamoxifen (TAM) is employed to treat premenopausal ER-positive breast cancer patients, but TAM resistance is the main reason affecting its efficacy. Thus, addressing TAM resistance is crucial for improving therapeutic outcomes. This study explored the potential role of Tinagl1, a secreted extracellular matrix protein, whose expression is compromised in TAM-resistant MCF-7 breast cancer cells (MCF-7R).
View Article and Find Full Text PDFComb Chem High Throughput Screen
January 2025
APIGENEX s.r.o., Poděbradská 173/5, Prague 19000, Czech Republic.
Objective: In search of efficient anticancer agents, we aimed at the design and synthesis of a library of tetrasubstituted alkenes. These are structural analogues of tamoxifen, one of the widely used anticancer therapeutics.
Methods: Our small organic compound library was prepared via a chemical synthesis in the solution using the Larock three-component coupling reaction, which is known to tolerate diverse functional groups.
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