Estrogen-ERα signaling and DNA hypomethylation co-regulate expression of stem cell protein PIWIL1 in ERα-positive endometrial cancer cells

Effects of cadmium exposure during pregnancy on genome-wide DNA methylation and the CREB/CREM pathway in the testes of male offspring rats

This experimental study explored the multigenerational and transgenerational effects of cadmium (Cd) exposure during pregnancy on the testicular tissue and spermatogenesis of male offspring rats. CdCl2 at different doses (0, 0.5, 1, 2 mg/kg/day) were dispensed to pregnant SD rats, thus producing generation F1. Adult females in F1 (PND 56) were mated with untreated fertile males so as to produce generation F2. Likewise, adult females in F2 were mated to produce generation F3. Damages to testicular tissue were observed in all the three generations, with serum testosterone (T) increased in F2 and F3. Notably, the genome-wide DNA methylation level in the testicular tissue of F1 was altered, as was the expression of F1-F3 methyltransferases. In addition, the expression of Creb/Crem pathway, a pathway critical for the metamorphosis from postmeiotic round spermatocytes to spermatozoa, was also remarkably altered in the three generations. In concludion, prenatal Cd exposure might bring multigenerational and transgenerational toxic effects to testes via genome-wide DNA methylation and the regulation of CREB/CREM pathway.

Roles of estrogen receptor α in endometrial carcinoma (Review)

Endometrial carcinoma (EC) is a group of endometrial epithelial malignancies, most of which are adenocarcinomas and occur in perimenopausal and postmenopausal women. It is one of the most common carcinomas of the female reproductive system. It has been shown that the occurrence and development of EC is closely associated with the interaction between estrogen (estradiol, E2) and estrogen receptors (ERs), particularly ERα. As a key nuclear transcription factor, ERα is a carcinogenic factor in EC. Its interactions with upstream and downstream effectors and co-regulators have important implications for the proliferation, metastasis, invasion and inhibition of apoptosis of EC. In the present review, the structure of ERα and the regulation of ERα in multiple dimensions are described. In addition, the classical E2/ERα signaling pathway and the crosstalk between ERα and other EC regulators are elucidated, as well as the therapeutic targeting of ERα, which may provide a new direction for clinical applications of ERα in the future.

Novel roles of PIWI proteins and PIWI-interacting RNAs in human health and diseases

Non-coding RNA has aroused great research interest recently, they play a wide range of biological functions, such as regulating cell cycle, cell proliferation, and intracellular substance metabolism. Piwi-interacting RNAs (piRNAs) are emerging small non-coding RNAs that are 24-31 nucleotides in length. Previous studies on piRNAs were mainly limited to evaluating the binding to the PIWI protein family to play the biological role. However, recent studies have shed more lights on piRNA functions; aberrant piRNAs play unique roles in many human diseases, including diverse lethal cancers. Therefore, understanding the mechanism of piRNAs expression and the specific functional roles of piRNAs in human diseases is crucial for developing its clinical applications. Presently, research on piRNAs mainly focuses on their cancer-specific functions but lacks investigation of their expressions and epigenetic modifications. This review discusses piRNA's biogenesis and functional roles and the recent progress of functions of piRNA/PIWI protein complexes in human diseases. Video Abstract.

Srd5a1 is Differentially Regulated and Methylated During Prepubertal Development in the Ovary and Hypothalamus

5α-reductase-1 catalyzes production of various steroids, including neurosteroids. We reported previously that expression of its encoding gene, Srd5a1, drops in murine ovaries and hypothalamic preoptic area (POA) after early-life immune stress, seemingly contributing to delayed puberty and ovarian follicle depletion, and in the ovaries the first intron was more methylated at two CpGs. Here, we hypothesized that this CpG-containing locus comprises a methylation-sensitive transcriptional enhancer for Srd5a1. We found that ovarian Srd5a1 mRNA increased 8-fold and methylation of the same two CpGs decreased up to 75% between postnatal days 10 and 30. Estradiol (E2) levels rise during this prepubertal stage, and exposure of ovarian cells to E2 increased Srd5a1 expression. Chromatin immunoprecipitation in an ovarian cell line confirmed ESR1 binding to this differentially methylated genomic region and enrichment of the enhancer modification, H3K4me1. Targeting dCas9-DNMT3 to this locus increased CpG2 methylation 2.5-fold and abolished the Srd5a1 response to E2. In the POA, Srd5a1 mRNA levels decreased 70% between postnatal days 7 and 10 and then remained constant without correlation to CpG methylation levels. Srd5a1 mRNA levels did not respond to E2 in hypothalamic GT1-7 cells, even after dCas9-TET1 reduced CpG1 methylation by 50%. The neonatal drop in POA Srd5a1 expression occurs at a time of increasing glucocorticoids, and treatment of GT1-7 cells with dexamethasone reduced Srd5a1 mRNA levels; chromatin immunoprecipitation confirmed glucocorticoid receptor binding at the enhancer. Our findings on the tissue-specific regulation of Srd5a1 and its methylation-sensitive control by E2 in the ovaries illuminate epigenetic mechanisms underlying reproductive phenotypic variation that impact life-long health.

Cancer-biomarkers associated with sex hormone receptors and recent therapeutic advancements: a comprehensive review

Hormones and its regulation plays vital role in causing breast, prostate, ovarian and endometrial cancers collectively known as hormone-sensitive cancers. This review discusses the various functions of the sex hormones and the biological pathways involved in causing hormone-associated cancer under differential regulation. We have also attempted to explore the biomarkers associated with the cancers and the current therapeutic availability to treat such cancers. Among various sex hormones such as estrogen, progesterone and androgen, estrogen the female sex hormone and its receptor had a major contribution in causing cancer and hence are considered a predominant target in treating the associated cancers. Other hormones and receptors such a androgen, progesterone, and their respective receptors were also reported to have a significant correlation in causing cancers. Apart from these receptors certain enzymes that act as precursors or as promoters are also targeted for treatment strategies. The drugs commonly used belong to the selective drug classes such as selective estrogen receptor modulators and selective progesterone receptor modulators. In the case of androgen regulation androgen deprivation therapies are practiced. It is also suggested that the use of natural substances to treat cancer could prevent resistance and reduce side effects. Identification of significant targets and the discovery of many efficient drugs shall be possible in the future with better understanding of hormone regulation and its influence on cancer causative mechanisms.

Short-term exposure to norethisterone affected swimming behavior and antioxidant enzyme activity of medaka larvae, and led to masculinization in the adult population

Norethisterone (NET), one of the synthetic progestins, is detected with increasing frequency in the water environment and distributed in the ocean, with a potential toxicity risk to marine organisms. However, current studies on the adverse effects of progestins (including NET) in aquatic environments have focused on freshwater organisms, mainly fish. In the present, marine medaka (Oryzias melastigma) larvae were exposed to 91.31 ng/L NET for 10 days, and then the swimming behavior, oxidation-antioxidant-related enzyme activities, sex and thyroid hormone levels, and the gene transcription patterns of the larvae were measured. After NET treatment, medaka larvae were raised in artificial seawater until 5 months of age, and the sex ratio was counted. Ten-day exposure to 91.31 ng/L NET inhibited swimming behavior, of marine medaka larvae, which showed that the time in the resting state was significantly prolonged, while the time in the large motor state was significantly reduced; disrupted oxidative-antioxidant system, significantly up-regulated the enzymatic activities of reactive oxygen species (ROS), malondialdehyde (MDA), and glutathione peroxidase (GSH-Px); affected the hormone levels of larvae, lowered 11- keto testosterone (11-KT) and triiodothyronine (T3) concentrations. RNA-seq results showed that 91.31 ng/L NET exposure for 10 days changed the transcript levels of 275 genes, of which 28 were up-regulated and 247 were down-regulated. Differentially expressed genes (DEGs) were mainly significantly enriched in piwi interacting RNA (piRNA), gonadal development, gametogenesis, and steroidogenesis biological processes, etc. After removing NET exposure and returning to breeding for 140 days, a significant increase in male proportions (69.67%) was observed in sexually mature medaka populations in the NET-treated group. These results show that exposure to 91.31 ng/L NET for 10 days can lead to various adverse effects on marine medaka larvae. These findings shed light on the potential ecological risks of synthetic progestins to marine organisms.

The interplay of sex steroid hormones and microRNAs in endometrial cancer: current understanding and future directions

Introduction

Endometrial cancer is a hormone-dependent malignancy, and sex steroid hormones play a crucial role in its pathogenesis. Recent studies have demonstrated that microRNAs (miRNAs) can regulate the expression of sex steroid hormone receptors and modulate hormone signaling pathways. Our aim is to provide an overview of the current understanding of the role of miRNAs in endometrial cancer regulated by sex steroid hormone pathways.

Methods

A thorough literature search was carried out in the PubMed database. The articles published from 2018 to the present were included. Keywords related to miRNAs, endometrial cancer, and sex steroid hormones were used in the search.

Results

Dysregulation of miRNAs has been linked to abnormal sex steroid hormone signaling and the development of endometrial cancer. Various miRNAs have been identified as modulators of estrogen and progesterone receptor expression, and the miRNA expression profile has been shown to be a predictor of response to hormone therapy. Additionally, specific miRNAs have been implicated in the regulation of genes involved in hormone-related signaling pathways, such as the PI3K/Akt/mTOR and MAPK/ERK pathways.

Conclusion

The regulation of sex steroid hormones by miRNAs is a promising area of research in endometrial cancer. Future studies should focus on elucidating the functional roles of specific miRNAs in sex steroid hormone signaling and identifying novel miRNA targets for hormone therapy in endometrial cancer management.

Unexplored Functions of Sex Hormones in Glioblastoma Cancer Stem Cells

Biological sex impacts a wide array of molecular and cellular functions that impact organismal development and can influence disease trajectory in a variety of pathophysiological states. In nonreproductive cancers, epidemiological sex differences have been observed in a series of tumors, and recent work has identified previously unappreciated sex differences in molecular genetics and immune response. However, the extent of these sex differences in terms of drivers of tumor growth and therapeutic response is less clear. In glioblastoma (GBM), the most common primary malignant brain tumor, there is a male bias in incidence and outcome, and key genetic and epigenetic differences, as well as differences in immune response driven by immune-suppressive myeloid populations, have recently been revealed. GBM is a prototypic tumor in which cellular heterogeneity is driven by populations of therapeutically resistant cancer stem cells (CSCs) that underlie tumor growth and recurrence. There is emerging evidence that GBM CSCs may show a sex difference, with male tumor cells showing enhanced self-renewal, but how sex differences impact CSC function is not clear. In this mini-review, we focus on how sex hormones may impact CSCs in GBM and implications for other cancers with a pronounced CSC population. We also explore opportunities to leverage new models to better understand the contribution of sex hormones vs sex chromosomes to CSC function. With the rising interest in sex differences in cancer, there is an immediate need to understand the extent to which sex differences impact tumor growth, including effects on CSC function.

The Regulation and Role of piRNAs and PIWI Proteins in Cancer

P-element-induced wimpy testis (PIWI)-interacting RNAs (piRNAs) are regulatory small non-coding RNAs that participate in transposon inactivation, chromatin regulation, and endogenous gene regulation. Numerous genetic and epigenetic factors regulate cell proliferation and tumor metastasis. PIWI proteins and piRNAs have been revealed to function in regulating upstream or downstream of oncogenes or tumor-suppressor genes in cancer tissues. In the present review, we summarize major recent findings in uncovering the regulation and role of PIWI proteins and piRNAs in tumorigenesis and highlight some of the promising applications of specific piRNAs in cancer therapeutics and as cancer biomarkers.

Critical Roles of PIWIL1 in Human Tumors: Expression, Functions, Mechanisms, and Potential Clinical Implications

P-element-induced wimpy testis (PIWI)-interacting RNAs (piRNAs) are a class of small non-coding RNA molecules that are 24-31 nucleotides in length. PiRNAs are thought to bind to PIWI proteins (PIWL1-4, a subfamily of Argonaute proteins), forming piRNA/PIWI complexes that influence gene expression at the transcriptional or post-transcriptional levels. However, it has been recently reported that the interaction of PIWI proteins with piRNAs does not encompass the entire function of PIWI proteins in human tumor cells. PIWIL1 (also called HIWI) is specifically expressed in the testis but not in other normal tissues. In tumor tissues, PIWIL1 is frequently overexpressed in tumor tissues compared with normal tissues. Its high expression is closely correlated with adverse clinicopathological features and shorter patient survival. Upregulation of PIWIL1 drastically induces tumor cell proliferation, epithelial-mesenchymal transition (EMT), invasion, cancer stem-like properties, tumorigenesis, metastasis and chemoresistance, probably via piRNA-independent mechanisms. In this article, we summarize the current existing literature on PIWIL1 in human tumors, including its expression, biological functions and regulatory mechanisms, providing new insights into how the dysregulation of PIWIL1 contributes to tumor initiation, development and chemoresistance through diverse signaling pathways. We also discuss the most recent findings on the potential clinical applications of PIWIL1 in cancer diagnosis and treatment.

[Single nucleotide polymorphism of rs28416520 in Piwil1 gene promoter region is associated with an increased risk of gastric cancer]

OBJECTIVE

To analyze the correlation between the single nucleotide polymorphisms (SNPs) in the promoter of Piwil1 gene and gastric cancer.

METHODS

The expression of Piwil1 mRNA in the tumor tissues of 3 patients with gastric cancer was detected by RT-qPCR, and RNA-Sequencing data from the Cancer RNA-Seq Nexus were analyzed for Piwil1 mRNA expression in gastric patients. Blood samples were collected from 24 gastric cancer patients and 29 healthy control subjects for PCR amplification of Piwil1 gene promoter region. The SNP loci in the promoter region of Piwil1 gene were determined by direct sequencing, and the results were analyzed by SnapGene software.

RESULTS

Analysis of the data from Cancer RNA-Seq Nexus and the results of RT-qPCR in 3 gastric cancer patients all showed significantly increased Piwil1 expression in gastric cancer tissues compared with the adjacent tissues. Seven SNP loci in two CpG regions of the Piwil1 gene promoter were genotyped, and only one SNP locus was found to be related to gastric cancer. The frequencies of GG, GA, and AA genotypes at the rs28416520 locus in CpG 67 region were 79.2%, 16.7%, and 4.1% in the gastric cancer group, and were 37.9%, 55.2%, and 6.9% in the control group, respectively, showing a significantly higher frequency of the GG genotype in gastric cancer group (OR=0.144, 95%CI: 0.045-0.564, χ²=9.071, P < 0.01). The frequency of allele G of the rs28416520 locus was significantly higher in gastric cancer group than in the control group (87.5% vs 65.5%; OR=0.271, 95%CI: 0.099-0.766, χ²=6.856, P < 0.01). The genotype or allele frequencies of the other 6 SNPs locus did not differ significantly between gastric cancer group and control group.

CONCLUSIONS

The expression of Piwil1 is increased in gastric cancer tissues as compared with the adjacent tissues. The GG genotype and G allele of rs28416520 within CpG 67 region are associated with an increased risk of gastric cancer.

Involvement of the Estrogen and Progesterone Axis in Cancer Stemness: Elucidating Molecular Mechanisms and Clinical Significance

Estrogen and progesterone regulate the growth and development of human tissues, including the reproductive system and breasts, through estrogen and progesterone receptors, respectively. These receptors are also important indicators for the clinical prognosis of breast cancer and various reproductive cancers. Many studies have reported that cancer stem cells (CSCs) play a key role in tumor initiation, progression, metastasis, and recurrence. Although the role of estrogen and progesterone in human organs and various cancers has been studied, the molecular mechanisms underlying the action of these hormones on CSCs remain unclear. Therefore, further elucidation of the effects of estrogen and progesterone on CSCs should provide a new direction for developing pertinent therapies. In this review, we summarize the current knowledge on the estrogen and progesterone axis involved in cancer stemness and discuss potential therapeutic strategies to inhibit CSCs by targeting relevant pathways.