Nomegestrol acetate (NOMAC) has been successfully used for the treatment of some gynecological disorders, and as a combined oral contraceptive with approval in many countries. In this study, we investigated the effects of NOMAC on human endometrial cancer cells in vitro and in vivo. The proliferation of human endometrial cancer cells (RL95-2 and KLE) were assessed using CCK-8 and EdU incorporation assays. Whole-genome cDNA microarray analysis was used to identify the effects of NOMAC on gene expression profiles in RL95-2 cells. RL95-2 xenograft nude mice were treated with NOMAC (50, 100, and 200 mg/kg) or medroxyprogesterone acetate (MPA; 100 and 200 mg/kg) for 28 consecutive days. The results showed that NOMAC significantly inhibited the growth of RL95-2 cells in a concentration-dependent manner, but not in KLE cells. Further investigation demonstrated that NOMAC produced a stronger inhibition of tumor growth (inhibition rates for 50, 100, and 200 mg/kg NOMAC were 24.74%, 47.04%, and 58.06%, respectively) than did MPA (inhibition rates for 100 and 200 mg/kg MPA were 41.06% and 27.01%, respectively) in the nude mice bearing the cell line of RL95-2. NOMAC altered the expression of several genes related to cancer cell proliferation, including SUFU and Wnt7a. The upregulation of SUFU and Wnt7a was confirmed using real-time quantitative polymerase chain reaction and Western blotting in RL95-2 cells and RL95-2 xenograft tumor tissues, but not in KLE cells. These data indicate that NOMAC can inhibit the proliferation of RL95-2 cell in vitro and suppress the growth of xenografts in the nude mice bearing the cell line of RL95-2 in vivo. This effect could be related to the upregulating expression of SUFU and Wnt7a.

This study investigated the effect of a novel progestin and its combination with metformin on the growth of endometrial cancer (EC) cells. Inhibitory effects of four progestins, including nomegestrol acetate (NOMAC), medroxyprogesterone acetate, levonorgestrel, and cyproterone acetate, were evaluated in RL95-2, HEC-1A, and KLE cells using cell counting kit-8 assay. Flow cytometry was performed to detect cell cycle and apoptosis. The activity of Akt (protein kinase B), mTOR (mammalian target of rapamycin) and its downstream substrates 4EBP1 (4E-binding protein 1) and eIF4G (Eukaryotic translation initiation factor 4G) were assayed by Western blotting. Nude mice were used to assess antitumor effects in vivo. NOMAC inhibited the growth of RL95-2 and HEC-1A cells, accompanied by arresting the cell cycle at G0/G1 phase, inducing apoptosis, and markedly down-regulating the level of phosphorylated mTOR/4EBP1/eIF4G in both cell lines (p < 0.05). Metformin significantly increased the inhibitory effect of and apoptosis induced by NOMAC and strengthened the depressive effect of NOMAC on activity of mTOR and its downstream substrates, compared to their treatment alone (p < 0.05). In xenograft tumor tissues, metformin (100 mg/kg) enhanced the suppressive effect of NOMAC (100 mg/kg) on mTOR signaling and increased the average concentration of NOMAC by nearly 1.6 times compared to NOMAC treatment alone. Taken together, NOMAC suppressing the growth of EC cells likely correlates to down-regulating the activity of the mTOR pathway and metformin could strengthen this effect. Our findings open a new window for the selection of progestins in hormone therapy of EC.

In the present study, a novel dimer, SM1044, selected from a series of dihydroartemisinin (DHA) derivatives containing nitrogen atoms comprising simple aliphatic amine linkers, showed strong growth inhibition in six types of human endometrial cancer (EC) cells, with half maximal inhibitory concentration (IC₅₀) and 95% confidence interval (CI) < 3.6 (1.16~11.23) μM. SM1044 evoked apoptosis and activated caspase-3, −8 and −9 in a concentration- and time-dependent manner, and these effects were manifested early in RL95-2 compared to KLE cells, possibly correlated with the induction of intracellular ONOO⁻. Catalase and uric acid attenuated the growth inhibitory effects of SM1044 on EC cells, but sodium pyruvate did not. In vivo, the average xenograft tumour growth inhibition rates ranged from 35.8% to 49.9%, respectively, after 2.5 and 5.0 mg/kg SM1044 intraperitoneal treatment, and no obvious behavioural and histopathological abnormalities were observed in SM1044-treated mice in this context. SM1044 predominantly accumulated in the uteri of mice after a single injection. SM1044 displayed efficacy as a tumour suppressor with distinct mechanism of action and unique tissue distribution, properties that distinguish it from other artemisinin analogues. Our findings provide a new clue for artemisinin analogue against cancer.

Progestin resistance is a major obstacle to conservative therapy in patients with endometrial cancer (EC) and endometrial atypical hyperplasia (EAH). However, the related inducing factor is yet unclear. In this study, thyroid hormone and its receptor α (TRα) and β (TRβ) of patients were assayed. THRB-silenced RL95-2 and KLE EC cells were cultured to investigate the response of progestins. Transcriptomics and Western blotting were performed to investigate the changes in signaling pathways. We found that THRB, rather than THRA, knockdown promoted the viability and motilities of RL95-2 cells but not KLE cells. The suppressive effect of progestins on cell growth and motility significantly decreased in THRB-silenced RL95-2 cells. Multiple proliferation-related signaling pathways were enriched, and the activities of mammalian targets of rapamycin (mTOR)/4e-binding protein 1 (4EBP1)/eukaryotic translation initiation factor 4G (eIF4G) rather than phosphorylated protein kinase B (Akt) were remarkably boosted. Progestin treatment enhanced the effects, and the augmentation was partially abated on supplementation with T3. In THRB-knockdown KLE cells, the progestins-activated partial signaling pathway expression (either mTOR or eIF4G), and supplementation with T3 did not induce noticeable alterations. The serum levels of triiodothyronine (T3) were significantly lower in patients with EC compared with healthy women. A strong expression of TRβ was observed in most patients with EC and EAH sensitive to progestin treatment. In contrast, TRα positive expression was detected in less than half of the patients sensitive to progestin therapy. In conclusion, THRB knockdown enhanced the viability and motility of type I EC cells and attenuated the suppressive effects of progestins by activating the mTOR-4EBP1/eIF4G pathway. Lower expression of THRB is likely correlated with progesterone resistance.

Background: Spermatozoa become mature and acquire fertilizing capacity during their passage through the epididymal lumen. In this study, we identified new epididymal luminal fluid proteins involved in sperm maturation in infertile rats by dutasteride, a dual 5α-reductase inhibitor, in order to provide potential epididymal targets for new contraceptives and infertility treatment. Methods: Male rats were treated with dutasteride for 28 consecutive days. We observed the protein expression profiles in the epididymal luminal fluids in infertile and normal rats using isobaric tags for relative and absolute quantitation (iTRAQ) technique. The confidence of proteome data was validated by enzyme-linked immunosorbent assays. Results: 1045 proteins were tested, and 23 of them presented different expression profiling in the infertile and normal rats. The seven proteins were down-regulated, and 16 proteins were up-regulated. Among the seven proteins which were significantly down-regulated by dutasteride in the epididymal luminal fluids, there were three β-defensins (Defb2, Defb18 and Defb39), which maybe the key proteins involved in epididymal sperm maturation and male fertility. Conclusions: We report for the first time that dutasteride influences the protein expression profiling in the epididymal luminal fluids of rats, and this result provides some new epididymal targets for male contraception and infertility therapy.