Selective Estrogen Receptor Modulators in Gynecology Practice

ERβ-activated LINC01018 promotes endometriosis development by regulating the CDC25C/CDK1/CyclinB1 pathway

Endometriosis refers to as an estrogen-dependent disease. Estrogen receptor β (ERβ), the main estrogen receptor subtype which is encoded by the estrogen receptor 2 (ESR2) gene, can mediate the action of estrogen in endometriosis. Although selective estrogen receptor modulators can target the ERβ, they are not specific due to the wide distribution of ERβ. Recently, long noncoding RNAs have been implicated in endometriosis. Therefore, we aim to explore and validate the downstream regulatory mechanism of ERβ, and to investigate the potential role of long intergenic noncoding RNA 1018 (LINC01018) as a nonhormonal treatment for endometriosis. Our study demonstrates that the expression levels of ESR2 and LINC01018 are increased in ectopic endometrial tissues and reveals a significant positive correlation between the ESR2 and LINC01018 expression. Mechanistically, ERβ directly binds to an estrogen response element located in the LINC01018 promoter region and activates LINC01018 transcription. Functionally, ERβ can regulate the CDC25C/CDK1/CyclinB1 pathway and promote ectopic endometrial stromal cell proliferation via LINC01018 in vitro. Consistent with these findings, the knockdown of LINC01018 inhibits endometriotic lesion proliferation in vivo. In summary, our study demonstrates that the ERβ/LINC01018/CDC25C/CDK1/CyclinB1 signaling axis regulates endometriosis progression.

A review of synthetic strategy, SAR, docking, simulation studies, and mechanism of action of isoxazole derivatives as anticancer agents

Breast cancer (BC) is a global health concern and the leading cause of cancerous death among women across the world, BC has been characterized by fresh lump in the breast or underarm (armpit), thickened or swollen. Worldwide estimated 9.6 million deaths in 2018-2019. Numerous drugs have been approved by FDA for BC treatment but showed numerous adverse effects like bioavailability issues, selectivity issues, and toxicity issues. Therefore, there is an immediate need to develop new molecules that are non-toxic and more efficient for treating cancer. Isoxazole derivatives have gained popularity over the few years due to their effective antitumor potential. These derivatives work against cancer by inhibiting the thymidylate enzyme, inducing apoptosis, inhibiting tubulin polymerization, protein kinase inhibition, and aromatase inhibition. In this study, we have concentrated on the isoxazole derivative with structure-activity relationship study, various synthesis techniques, mechanism of action, docking, and simulation studies pertaining to BC receptors. Hence the development of isoxazole derivatives with improved therapeutic efficacy will inspire further progress in improving human health.Communicated by Ramaswamy H. Sarma.

Current and novel approaches in the pharmacological treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most lethal malignant tumours worldwide. The mortality-to-incidence ratio is up to 91.6% in many countries, representing the third leading cause of cancer-related deaths. Systemic drugs, including the multikinase inhibitors sorafenib and lenvatinib, are first-line drugs used in HCC treatment. Unfortunately, these therapies are ineffective in most cases due to late diagnosis and the development of tumour resistance. Thus, novel pharmacological alternatives are urgently needed. For instance, immune checkpoint inhibitors have provided new approaches targeting cells of the immune system. Furthermore, monoclonal antibodies against programmed cell death-1 have shown benefits in HCC patients. In addition, drug combinations, including first-line treatment and immunotherapy, as well as drug repurposing, are promising novel therapeutic alternatives. Here, we review the current and novel pharmacological approaches to fight HCC. Preclinical studies, as well as approved and ongoing clinical trials for liver cancer treatment, are discussed. The pharmacological opportunities analysed here should lead to significant improvement in HCC therapy.

Unconventional isoquinoline-based SERMs elicit fulvestrant-like transcriptional programs in ER+ breast cancer cells

Estrogen receptor alpha (ERα) is a ligand-dependent master transcriptional regulator and key driver of breast cancer pathology. Small molecule hormones and competitive antagonists favor unique ERα conformational ensembles that elicit ligand-specific transcriptional programs in breast cancer and other hormone-responsive tissues. By affecting disparate ligand binding domain structural features, unconventional ligand scaffolds can redirect ERα genomic binding patterns to engage novel therapeutic transcriptional programs. To improve our understanding of these ERα structure-transcriptional relationships, we develop a series of chemically unconventional antagonists based on the antiestrogens elacestrant and lasofoxifene. High-resolution x-ray co-crystal structures show that these molecules affect both classical and unique structural motifs within the ERα ligand binding pocket. They show moderately reduced antagonistic potencies on ERα genomic activities but are effective anti-proliferative agents in luminal breast cancer cells. Interestingly, they favor a 4-hydroxytamoxifen-like accumulation of ERα in breast cancer cells but lack uterotrophic activities in an endometrial cell line. Importantly, RNA sequencing shows that the lead molecules engage transcriptional pathways similar to the selective estrogen receptor degrader fulvestrant. This advance shows that fulvestrant-like genomic activities can be achieved without affecting ERα accumulation in breast cancer cells.

Estradiol and Estrogen-like Alternative Therapies in Use: The Importance of the Selective and Non-Classical Actions

Estrogen is one of the most important female sex hormones, and is indispensable for reproduction. However, its role is much wider. Among others, due to its neuroprotective effects, estrogen protects the brain against dementia and complications of traumatic injury. Previously, it was used mainly as a therapeutic option for influencing the menstrual cycle and treating menopausal symptoms. Unfortunately, hormone replacement therapy might be associated with detrimental side effects, such as increased risk of stroke and breast cancer, raising concerns about its safety. Thus, tissue-selective and non-classical estrogen analogues have become the focus of interest. Here, we review the current knowledge about estrogen effects in a broader sense, and the possibility of using selective estrogen-receptor modulators (SERMs), selective estrogen-receptor downregulators (SERDs), phytoestrogens, and activators of non-genomic estrogen-like signaling (ANGELS) molecules as treatment.

The Optimized Formulation of Tamoxifen-Loaded Niosomes Efficiently Induced Apoptosis and Cell Cycle Arrest in Breast Cancer Cells

The aim, as proof of concept, was to optimize niosomal formulations of tamoxifen in terms of size, morphology, encapsulation efficiency, and release kinetics for further treatment of the breast cancer (BC). Different assays were carried out to evaluate the pro-apoptotic and cytotoxicity impact of tamoxifen-loaded niosomes in two BC cells, MDA-MB-231 and SKBR3. In this study, tamoxifen was loaded in niosomes after optimization in the formulation. The formulation of niosomes supported maximized drug entrapment and minimized their size. The novel formulation showed improvement in storage stability, and after 60 days only, small changes in size, polydispersity index, and drug entrapment were observed. Besides, a pH-dependent release pattern of formulated niosomes displayed slow release at physiological pH (7.4) and a considerable increase of release at acidic pH (5.4), making them a promising candidate for drug delivery in the BC treatment. The cytotoxicity study exhibited high biocompatibility with MCF10A healthy cells, while remarkable inhibitory effects were observed after treatment of cancerous lines, MDA-MB-231, and SKBR3 cells. The IC50 values for the tamoxifen-loaded niosomes were significantly less than other groups. Moreover, treatment with drug-loaded niosomes significantly changed the gene expression pattern of BC cells. Statistically significant down-regulation of cyclin D, cyclin E, VEGFR-1, MMP-2, and MMP-9 genes and up-regulation of caspase-3 and caspase-9 were observed. These results were in correlation with cell cycle arrest, lessoned migration capacity, and increased caspase activity and apoptosis induction in cancerous cells. Optimization in the formulation of tamoxifen-loaded niosomes can make them a novel candidate for drug delivery in BC treatment.