lonaprisan and Breast-Neoplasms

Progesterone is a major female steroid hormone produced by the ovarian corpus luteum and by the placental syncytiotrophoblast during the second trimester. The biological effects of this steroid hormone are mediated by the ubiquitously expressed progesterone receptor. The exact link between progesterone and female reproductive organ cancer is a controversial issue with various cross-talks. The present review summarizes recent trends in the development of some (anti)progestagen in the cure and management of breast and uterine cancers.

Topics: Antineoplastic Agents; Breast Neoplasms; Estrenes; Estrogens; Female; Humans; Oxazoles; Progesterone; Pyrazoles; Receptors, Progesterone; Uterine Neoplasms

The progesterone-receptor (PR) antagonists onapristone (type I) and mifepristone (type II) showed modest activity in hormone-receptor-positive breast cancer; however, onapristone in particular was associated with hepatotoxicity. Lonaprisan is a novel, type III PR antagonist that was well tolerated in phase I studies.. This randomized, open-label, phase II study evaluated the efficacy and tolerability of lonaprisan as second-line endocrine therapy in postmenopausal women with stage IV, PR-positive, HER2-negative, metastatic breast cancer.. Patients received once-daily lonaprisan 25 mg (n = 34) or 100 mg (n = 34). The primary objective was not met (≥ 35% clinical benefit rate: complete/partial responses at any time until month 6 or stable disease [SD] for ≥ 6 months from start of treatment). There were no complete/partial responses. In the 25 mg and 100 mg groups, 6 of 29 patients (21%) and 2 of 29 patients (7%), respectively, had SD ≥ 6 months. Overall, 61 of 68 patients (90%) had ≥ 1 adverse event (AE), the most frequent (≥ 10% overall) being fatigue, hot flush, dyspnoea, nausea, asthenia, headache, constipation, vomiting, and decreased appetite; 33 patients had serious AEs.. Lonaprisan showed limited efficacy as second-line endocrine therapy in postmenopausal women with PR-positive metastatic breast cancer.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents, Hormonal; Breast Neoplasms; Estrenes; Female; Humans; Middle Aged; Receptors, Progesterone; Treatment Outcome

The ovarian steroid hormone progesterone is essential for normal mammary gland physiology but may also play a role in breast cancer. Highly potent and selective antiprogestins may therefore represent a new treatment option for this disease. Here we studied the effects of the new antiprogestin Lonaprisan on the T47D breast cancer cell line. Strong inhibition of cell proliferation and arrest in the G0/G1 phase were observed, as well as induction of a senescence-like phenotype. This was accompanied by p21 induction through direct binding of Lonaprisan-bound progesterone receptor (PR) to the promoter. Reduction of p21 levels blunted the antiproliferative effects of Lonaprisan. Mutation analysis showed that intact PR DNA-binding properties were needed for p21 induction. Phosphorylation of PR Ser345 was stimulated by Lonaprisan, but this post-translational modification was not required for p21 promoter activation, nor was the interaction with c-Src needed. These results support the rationale for using antiprogestins in breast cancer treatment and warrant further studies to better understand their mode of action.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cellular Senescence; Cyclin-Dependent Kinase Inhibitor p21; Estrenes; Female; Humans; Ligands; Mutation; Phosphorylation; Progesterone; Progestins; Promoter Regions, Genetic; Receptors, Progesterone; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Sp1 Transcription Factor

The progesterone receptor (PR) is a key regulator of female reproductive functions. Compounds with progesterone inhibiting effects (PR antagonists) have found numerous utilities in female reproductive health, ranging from contraception to potential treatment of progesterone-dependent diseases like uterine leiomyomas. Based on in vitro characteristics such as DNA binding activity and partial agonistic transcriptional behavior in the presence of protein kinase A activators (cyclic-AMP), three types of PR modulators with antagonistic properties have been defined. In this study, we analyzed the in vitro characteristics of the PR antagonist ZK 230211 in comparison to the classical antagonists onapristone and mifepristone. We focused on PR actions in genomic signaling pathways, including DNA binding activity, nuclear localization and association with the nuclear receptor corepressor (NCoR) as well as actions in non-genomic signaling, such as the activation of c-Src kinase signaling and cyclin D1 gene promoter activity. ZK 230211 represents a type of PR antagonist with increased inhibitory properties in comparison to mifepristone and onapristone. When liganded to the progesterone receptor, ZK 230211 induces a strong and persistent binding to its target response element (PRE) and increases NCoR recruitment in CV-1 cells. Furthermore, ZK 230211 displays less agonistic properties with regard to the association of PR isoform B and the cytoplasmic c-Src kinase in HeLa cells. It represses T47D cell cycle progression, in particular estradiol-induced S phase entry. In summary, our studies demonstrate ZK 230211 to be a type III progesterone receptor antagonist which is characterized by very strong DNA binding activity and strong antiproliferative effects in the cancer cell lines HeLa and T47D.

Topics: Adenocarcinoma; Animals; Breast Neoplasms; Cell Nucleus; Cell Proliferation; Cells, Cultured; Chlorocebus aethiops; Cytostatic Agents; Drug Evaluation, Preclinical; Efficiency; Estrenes; Female; HeLa Cells; Humans; Protein Binding; Protein Transport; Receptors, Progesterone; Response Elements; Transcriptional Activation