miR-214-mediated downregulation of RNF8 induces chromosomal instability in ovarian cancer cells

Current Understanding on Why Ovarian Cancer Is Resistant to Immune Checkpoint Inhibitors

The standard treatment of ovarian cancer (OC) patients, including debulking surgery and first-line chemotherapy, is unsatisfactory because of recurrent episodes in the majority (~70%) of patients with advanced OC. Clinical trials have shown only a modest (10-15%) response of OC individuals to treatment based on immune checkpoint inhibitors (ICIs). The resistance of OC to therapy is caused by various factors, including OC heterogeneity, low density of tumor-infiltrating lymphocytes (TILs), non-cellular and cellular interactions in the tumor microenvironment (TME), as well as a network of microRNA regulating immune checkpoint pathways. Moreover, ICIs are the most efficient in tumors that are marked by high microsatellite instability and high tumor mutation burden, which is rare among OC patients. The great challenge in ICI implementation is connected with distinguishing hyper-, pseudo-, and real progression of the disease. The understanding of the immunological, molecular, and genetic mechanisms of OC resistance is crucial to selecting the group of OC individuals in whom personalized treatment would be beneficial. In this review, we summarize current knowledge about the selected factors inducing OC resistance and discuss the future directions of ICI-based immunotherapy development for OC patients.

Pervasive role of the long noncoding RNA DNM3OS in development and diseases

Thousands of unique noncoding RNAs (ncRNAs) are expressed in human cells, some are tissue or cell type specific whereas others are considered as house-keeping molecules. Studies over the last decade have modified our perception of ncRNAs from transcriptional noise to functional regulatory transcripts that influence a variety of molecular processes such as chromatin remodeling, transcription, post-transcriptional modifications, or signal transduction. Consequently, aberrant expression of many ncRNAs plays a causative role in the initiation and progression of various diseases. Since the identification of its developmental role, the long ncRNA DNM3OS (Dynamin 3 Opposite Strand) has attracted attention of researchers in distinct fields including oncology, fibroproliferative diseases, or bone disorders. Mechanistic studies have in particular revealed the multifaceted nature of DNM3OS and its important pathogenic role in several human disorders. In this review, we summarize the current knowledge of DNM3OS functions in diseases, with an emphasis on its potential as a novel therapeutic target. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.

Epi-miRNAs: Regulators of the Histone Modification Machinery in Human Cancer

Cancer is a leading cause of death and disability worldwide. Epigenetic deregulation is one of the most critical mechanisms in carcinogenesis and can be classified into effects on DNA methylation and histone modification. MicroRNAs are small noncoding RNAs involved in fine-tuning their target genes after transcription. Various microRNAs control the expression of histone modifiers and are involved in a variety of cancers. Therefore, overexpression or downregulation of microRNAs can alter cell fate and cause malignancies. In this review, we discuss the role of microRNAs in regulating the histone modification machinery in various cancers, with a focus on the histone-modifying enzymes such as acetylases, deacetylases, methyltransferases, demethylases, kinases, phosphatases, desumoylases, ubiquitinases, and deubiquitinases. Understanding of microRNA-related aberrations underlying histone modifiers in pathogenesis of different cancers can help identify novel therapeutic targets or early detection approaches that allow better management of patients or monitoring of treatment response.

Single-cell transcriptome atlas of human mesenchymal stem cells exploring cellular heterogeneity

BACKGROUND

The heterogeneity of mesenchymal stem cells (MSCs) is poorly understood, thus limiting clinical application and basic research reproducibility. Advanced single-cell RNA sequencing (scRNA-seq) is a robust tool used to analyse for dissecting cellular heterogeneity. However, the comprehensive single-cell atlas for human MSCs has not been achieved.

METHODS

This study used massive parallel multiplexing scRNA-seq to construct an atlas of > 130 000 single-MSC transcriptomes across multiple tissues and donors to assess their heterogeneity. The most widely clinically utilised tissue resources for MSCs were collected, including normal bone marrow (n = 3), adipose (n = 3), umbilical cord (n = 2), and dermis (n = 3).

RESULTS

Seven tissue-specific and five conserved MSC subpopulations with distinct gene-expression signatures were identified from multiple tissue origins based on the high-quality data, which has not been achieved previously. This study showed that extracellular matrix (ECM) highly contributes to MSC heterogeneity. Notably, tissue-specific MSC subpopulations were substantially heterogeneous on ECM-associated immune regulation, antigen processing/presentation, and senescence, thus promoting inter-donor and intra-tissue heterogeneity. The variable dynamics of ECM-associated genes had discrete trajectory patterns across multiple tissues. Additionally, the conserved and tissue-specific transcriptomic-regulons and protein-protein interactions were identified, potentially representing common or tissue-specific MSC functional roles. Furthermore, the umbilical-cord-specific subpopulation possessed advantages in immunosuppressive properties.

CONCLUSION

In summary, this work provides timely and great insights into MSC heterogeneity at multiple levels. This MSC atlas taxonomy also provides a comprehensive understanding of cellular heterogeneity, thus revealing the potential improvements in MSC-based therapeutic efficacy.

MicroRNA-214 in Health and Disease

MicroRNAs (miRNAs) are endogenously expressed, non-coding RNA molecules that mediate the post-transcriptional repression and degradation of mRNAs by targeting their 3′ untranslated region (3′-UTR). Thousands of miRNAs have been identified since their first discovery in 1993, and miR-214 was first reported to promote apoptosis in HeLa cells. Presently, miR-214 is implicated in an extensive range of conditions such as cardiovascular diseases, cancers, bone formation and cell differentiation. MiR-214 has shown pleiotropic roles in contributing to the progression of diseases such as gastric and lung cancers but may also confer cardioprotection against excessive fibrosis and oxidative damage. These contrasting functions are achieved through the diverse cast of miR-214 targets. Through silencing or overexpressing miR-214, the detrimental effects can be attenuated, and the beneficial effects promoted in order to improve health outcomes. Therefore, discovering novel miR-214 targets and understanding how miR-214 is dysregulated in human diseases may eventually lead to miRNA-based therapies. MiR-214 has also shown promise as a diagnostic biomarker in identifying breast cancer and coronary artery disease. This review provides an up-to-date discussion of miR-214 literature by describing relevant roles in health and disease, areas of disagreement, and the future direction of the field.

miRNA dysregulation is an emerging modulator of genomic instability

Genomic instability consists of a range of genetic alterations within the genome that contributes to tumor heterogeneity and drug resistance. It is a well-established characteristic of most cancer cells. Genome instability induction results from defects in DNA damage surveillance mechanisms, mitotic checkpoints and DNA repair machinery. Accumulation of genetic alterations ultimately sets cells towards malignant transformation. Recent studies suggest that miRNAs are key players in mediating genome instability. miRNAs are a class of small RNAs expressed in most somatic tissues and are part of the epigenome. Importantly, in many cancers, miRNA expression is dysregulated. Consequently, this review examines the role of miRNA dysregulation as a causal step for induction of genome instability and subsequent carcinogenesis. We focus specifically on mechanistic studies assessing miRNA(s) and specific subtypes of genome instability or known modes of genome instability. In addition, we provide insight on the existing knowledge gaps within the field and possible ways to address them.

Current Implications of microRNAs in Genome Stability and Stress Responses of Ovarian Cancer

Genomic alterations and aberrant DNA damage signaling are hallmarks of ovarian cancer (OC), the leading cause of mortality among gynecological cancers worldwide. Owing to the lack of specific symptoms and late-stage diagnosis, survival chances of patients are significantly reduced. Poly (ADP-ribose) polymerase (PARP) inhibitors and replication stress response inhibitors present attractive therapeutic strategies for OC. Recent research has focused on ovarian cancer-associated microRNAs (miRNAs) that play significant regulatory roles in various cellular processes. While miRNAs have been shown to participate in regulation of tumorigenesis and drug responses through modulating the DNA damage response (DDR), little is known about their potential influence on sensitivity to chemotherapy. The main objective of this review is to summarize recent findings on the utility of miRNAs as cancer biomarkers, in particular, ovarian cancer, and their regulation of DDR or modified replication stress response proteins. We further discuss the suppressive and promotional effects of various miRNAs on ovarian cancer and their participation in cell cycle disturbance, response to DNA damage, and therapeutic functions in multiple cancer types, with particular focus on ovarian cancer. Improved understanding of the mechanisms by which miRNAs regulate drug resistance should facilitate the development of effective combination therapies for ovarian cancer.

Flavonoid display ability to target microRNAs in cancer pathogenesis

MicroRNAs (miRNAs) are non-coding, conserved, single-stranded nucleotide sequences involved in physiological and developmental processes. Recent evidence suggests an association between miRNAs' deregulation with initiation, promotion, progression, and drug resistance in cancer cells. Besides, miRNAs are known to regulate the epithelial-mesenchymal transition, angiogenesis, autophagy, and senescence in different cancer types. Previous reports proposed that apart from the antioxidant potential, flavonoids play an essential role in miRNAs modulation associated with changes in cancer-related proteins, tumor suppressor genes, and oncogenes. Thus, flavonoids can suppress proliferation, help in the development of drug sensitivity, suppress metastasis and angiogenesis by modulating miRNAs expression. In the present review, we summarize the role of miRNAs in cancer, drug resistance, and the chemopreventive potential of flavonoids mediated by miRNAs. The potential of flavonoids to modulate miRNAs expression in different cancer types demonstrate their selectivity and importance as regulators of carcinogenesis. Flavonoids as chemopreventive agents targeting miRNAs are extensively studied in vitro, in vivo, and pre-clinical studies, but their efficiency in targeting miRNAs in clinical studies is less investigated. The evidence presented in this review highlights the potential of flavonoids in cancer prevention/treatment by regulating miRNAs, although further investigations are required to validate and establish their clinical usefulness.

Absence of Sirtuin 1 impairs the testicular development in cattleyak by inactivating SF-1

Cattleyak, which are interspecific hybrids between cattle and yak, display much higher growth performances than yak. However, F1 male cattleyak are infertile due to defective testicular development. Sirtuin 1 (SIRT1) is a histone deacetylase that is essential for various biological processes, while the roles of testicular SIRT1 in yak and cattleyak are still poorly understood. Here, we found that SIRT1 was localized in various kinds of yak testicular cells except elongated spermatids while it was deficient in cattleyak testis. Further studies indicated that cattleyak testis exhibited decreased histone acetylation levels on H3 and H4. One of SIRT1 co-factors, steroidogenic factor-1 (SF-1), was lost in cattleyak testis at protein level. Expressions of several SF-1 target genes responsible for Sertoli cell development and steroidogenesis, including STAR, CYP11A1, CYP26B1, FDX1 and HSD3B, decreased significantly in cattleyak testis. In addition, SIRT1-mediated P53 acetylation was not responsible for the cell apoptosis in cattleyak testis. Taken together, our results suggested the deficiency of SIRT1 in yak testis caused inactivation of SF-1 and the impairment of testicular development. This research provides theoretical bases for understanding the mechanism of cattleyak sterility and gives new insights in revealing the roles of SIRT1 in regulating yak testicular development.

Esculentoside A rescues granulosa cell apoptosis and folliculogenesis in mice with premature ovarian failure

Follicular atresia is one of the main processes for the loss of granulosa cells and oocytes from the mammalian ovary and any impairment to premature ovarian failure. Large numbers of studies have demonstrated that granulosa cell apoptosis causes follicular atresia, yet the rescue of these cells remains elusive. We aimed to use Esculentoside A (3-O-b-D-glucopyranosyl-1, 4-b-D-xylopyranosyl) phytolaccagenin, a saponin extracted from Phytolacca esculenta roots, as a potential rescue agent for the apoptosis of granulosa cells. Our results revealed the rescue of normal body and ovary weights, normal ovarian histo-architecture of ovaries, and hormones levels with regular estrus cycle. Consistently, the expression of proliferating and anti-apoptotic markers, i.e. KI67 and BCL-2 in granulosa cells, was enhanced. Meanwhile, the expressions of pro-apoptotic markers, which were BAX and CASPASEs (CASPASE-9 and CASPASE-3), were prominently reduced in Esculentoside A-induced premature ovarian failure mice. Additionally, PPARγ, a potential therapeutic target, has also rescued its expression by treating the premature ovarian failure mice with Esculentoside A. Our results advocated that Esculentoside A could restore folliculogenesis in premature ovarian failure mice. Furthermore, it has the potential to be investigated as a therapeutic agent for premature ovarian failure.

Astragaloside IV suppresses transforming growth factor-β1-induced epithelial-mesenchymal transition through inhibition of Wnt/β-catenin pathway in glioma U251 cells

Astragaloside IV (AS#IV) has previously demonstrated antitumoractivity. We investigated the effect and mechanisms of AS#IV in relation to epithelial-mesenchymal transition (EMT), viainterference with the Wnt/β-catenin signaling pathway in gliomaU251 cells. Induction of glioma U251 cells by transforming growthfactor (TGF)#β1 activated EMT, including switching E#cadherin toN-cadherin and altering the expression of Wnt/β-catenin signalingpathway components such as vimentin, β-catenin, and cyclin-D1.AS-IV inhibited the viability, invasion, and migration of TGF-β1-induced glioma U251 cells. AS-IV also interfered with the TGF#β1-induced Wnt/β-catenin signaling pathway in glioma U251 cells.These findings indicate that AS#IV prohibits TGF#β1-induced EMTby disrupting the Wnt/β-catenin pathway in glioma U251 cells. AS#IV may thus be a potential candidate agent for treating glioma andother central nervous system tumors.

Potential microRNA-related targets in clearance pathways of amyloid-β: novel therapeutic approach for the treatment of Alzheimer's disease

Imbalance between amyloid-beta (Aβ) peptide synthesis and clearance results in Aβ deregulation. Failure to clear these peptides appears to cause the development of Alzheimer's disease (AD). In recent years, microRNAs have become established key regulators of biological processes that relate among others to the development and progression of neurodegenerative diseases, such as AD. This review article gives an overview on microRNAs that are involved in the Aβ cascade and discusses their inhibitory impact on their target mRNAs whose products participate in Aβ clearance. Understanding of the mechanism of microRNA in the associated signal pathways could identify novel therapeutic targets for the treatment of AD.

miR-214 inhibits epithelial-mesenchymal transition of breast cancer cells via downregulation of RNF8

MicroRNAs (miRNAs) are a class of endogenous noncoding genes that regulate gene expression at the posttranscriptional level. In recent decades, miRNAs have been reported to play important roles in tumor growth and metastasis, while some reported functions of a specific miRNA in tumorigenesis are contradictory. In this study, we reevaluated the role of miR-214, which has been reported to serve as an oncogene or anti-oncogene in breast cancer metastasis. We found that miR-214 inhibited breast cancer via targeting RNF8, a newly identified regulator that could promote epithelial-mesenchymal transition (EMT). Specifically, the survival rate of breast cancer patients was positively correlated with miR-214 levels and negatively correlated with RNF8 expression. The overexpression of miR-214 inhibited cell proliferation and invasion of breast cancer, while suppression of miR-214 by chemically modified antagomir enhanced the proliferation and invasion of breast cancer cells. Furthermore, miR-214 could modulate the EMT process via downregulating RNF8. To our knowledge, this is the first report that reveals the role of the miR-214-RNF8 axis in EMT, and our results demonstrate a novel mechanism for miR-214 acting as a tumor suppressor through the regulation of EMT.

Exosomal miR-214-5p Released from Glioblastoma Cells Modulates Inflammatory Response of Microglia after Lipopolysaccharide Stimulation through Targeting CXCR5

Methods:

The relative expression of miR-214-5p was determined by real-time PCR. Cell viability and migration were measured by MTT and transwell chamber assays, respectively. The secretory cytokines were measured with ELISA kits. The regulatory effect of miR-214-5p on CXCR5 expression was interrogated by luciferase reporter assay. Protein level was analyzed by Western blot.

Results:

We demonstrated that miR-214-5p was aberrantly overexpressed in GBM and associated with poorer clinical prognosis. High level of miR-214-5p significantly contributed to cell proliferation and migration. GBM-derived exosomal miR-214-5p promoted inflammatory response in primary microglia upon lipopolysaccharide challenge. We further identified CXCR5 as the direct target of miR-214- 5p in this setting.

Conclusion:

Overexpression of miR-214-5p in GBM modulated the inflammatory response in microglia via exosomal transfer.

MiR-194 regulates nasopharyngeal carcinoma progression by modulating MAP3K3 expression

Despite the recent development of treatment strategies for nasopharyngeal carcinoma, the effective management of this disease remains a challenging clinical problem. A better understanding of the regulatory roles of miR‐194 and mitogen‐activated protein kinase kinase kinase 3 (MAP3K3) in the nasopharyngeal‐carcinoma‐related gene network is required to address this issue. Here, we measured relative expression of miR‐194 in human nasopharyngeal carcinoma tissues and normal epithelial tissues by quantitative real time PCR. We transfected cultured CNE‐1 and C666‐1 cells with miR‐194 mimics, and then examined the effects on cell proliferation, cell migration and invasion. Luciferase reporter assay was used to validate the putative binding between miR‐194 and MAP3K3. We then examined the effect of knockdown and overexpression of MAP3K3 on cell tumorigenesis. Expression of miR‐194 is significantly down‐regulated in nasopharyngeal carcinoma specimens and tumor cell lines when compared with normal controls. In addition, miR‐194 suppressed tumor cell proliferation and viability, as well as migration and invasion of carcinoma cells. We found that miR‐194 binds the 3′ untranslated region of MAP3K3, and knockdown of miR‐194 inhibited nasopharyngeal carcinoma cell proliferation, migration and invasion. In accordance, overexpression of MAP3K3 reversed the inhibitory effects of miR‐194 in carcinoma cells. This study suggests that expression of miR‐194 is down‐regulated in nasopharyngeal carcinoma, and that miR‐194 can directly target MAP3K3 to regulate tumor progression. Given the pivotal involvement of MAP3K3 in nasopharyngeal carcinoma development, targeting miR‐194 may be a novel strategy for the treatment of nasopharyngeal carcinoma.

Role of miR-214 in modulating proliferation and invasion of human colon cancer SW620 cells

This study investigated the role of miR-214 in modulating proliferation and invasion of human colon cancer SW620 cells. Fifty-five patients with colon cancer who were treated in China-Japan Union Hospital of Jilin University from March 2014 to March 2015 were enrolled into this study. Their cancer and corresponding paracancerous tissues were collected and the expression levels of miR-214 were determined by RT-qPCR. A miR-214 expression vector was constructed. SW620 cells were transfected with the miR-214 expression vector and a blank vector. Cells transfected with the miR-214 expression vector were assigned to the miR-214 positive group and cells transfected with the blank vector were assigned to the miR-214 negative group. Cell proliferation, invasion and apoptosis were assessed by MTT assay, Transwell migration assay and TUNEL apoptosis assay, respectively. The RT-qPCR results showed that the expression level of miR-214 in colon cancer tissue, as well as in miR-214 negative cells, was significantly lower than that in paracancerous tissue (P<0.05 for both). In cell comparison, the expression level of miR-214 in the miR-214 positive group was significantly higher than that in the miR-214 negative group (0.483±0.001 vs. 0.172±0.001; P<0.05). The proliferation level of SW620 cells in the miR-214 positive group was lower than that in the miR-214 negative group (P<0.05). The Transwell migration assay indicated that there were less cells penetrating the membrane in the miR-214 positive group than in the miR-214 negative group (P<0.05). In addition, The apoptosis rate of cells in the miR-214 negative group was significantly lower than that in the miR-214 positive group (P<0.05). Finally, the low expression of miR-214 was found in colon cancer, indicating that miR-214 is a cancer suppressor playing an opposing role in colon cancer onset and progression. Therefore, miR-214 can promote apoptosis of colon cancer cells SW620 by inhibiting their proliferation and invasion.

Increasing sensitivity to DNA damage is a potential driver for human ovarian cancer

Ovarian cancer is one of the most common cancers among women, accounting for more deaths than any other gynecological diseases. However, the survival rate for ovarian cancer has not essentially improved over the past thirty years. Thus, to understand the molecular mechanism of ovarian tumorigenesis is important for optimizing the early diagnosis and treating this disease. In this study, we observed obvious DNA lesions, especially DNA double strand breaks (DSBs) accompanying cell cycle checkpoint activation, in the human epithelial ovarian cancer samples, which could be due to the impaired DNA response machinery. Following this line, we found that these DNA damage response-deficient primary cancer cells were hypersensitive to DNA damage and lost their ability to repair the DNA breaks, leading to genomic instability. Of note, three key DNA damage response factors, RNF8, Ku70, and FEN1 exhibited dramatically decreased expression level, implying the dysfunctional DNA repair pathways. Re-expression of wild type RNF8, Ku70, or FEN1 in these cells restored the DNA lesions and also partially rescued the cells from death. Our current study therefore proposes that accumulated DNA lesions might be a potential driver of ovarian cancer and the impaired DNA damage responders could be the targets for clinical treatment.

Silencing of E3 Ubiquitin Ligase RNF8 Enhances Ionizing Radiation Sensitivity of Medulloblastoma Cells by Promoting the Deubiquitination of PCNA

DNA damage response induced by ionizing radiation (IR) is an important event involved in the sensitivity and efficiency of radiotherapy in human medulloblastoma. RNF8 is an E3 ubiquitin ligase and has key roles in the process of DNA damage and repair. Our study aimed to evaluate the effect of RNF8 in the DNA damage repair induced by IR exposure in medulloblastoma cells. We found that the levels of RNF8 were significantly upregulated by γ-ray irradiation in a dose-dependent manner in medulloblastoma cells and colocalized with γ-H2AX, a sensitive marker of DNA double-strand breaks induced by γ-ray radiation. RNF8 knockdown was observed to enhance the sensitivity of IR in medulloblastoma cells, as evaluated by reduced cell survival. The apoptosis and cell cycle arrest of medulloblastoma cells were dramatically increased by RNF8 suppression after IR treatment. Furthermore, RNF8 inhibition did not affect the protein levels of BRCA1, a crucial protein involved in IR-induced DNA damage repair, but significantly decreased the recruitment of BRCA1 and increased the level of γ-H2AX at DNA damage sites compared to the control. A significant increase in OTM was observed in medulloblastoma cells treated by RNF8 shRNA after exposure to IR, indicating the effect of RNF8 on DNA damage and repair. Additionally, PCNA, a major target for ubiquitin modification during DNA damage response, was found to be monoubiquitinated by E3 ligase RNF8 and might contribute to the low radiosensitivity in medulloblastoma cells. Altogether, our findings may provide RNF8 as a novel target for the improvement of radiotherapy in medulloblastoma.

The expression of miRNAs is associated with tumour genome instability and predicts the outcome of ovarian cancer patients treated with platinum agents

miRNAs, a class of short but stable noncoding RNA molecules, have been revealed to play important roles in the DNA damage response (DDR). However, their functions in cancer genome instability and the consequent clinical effect as the response to chemotherapy have not been fully elucidated. In this study, we utilized multidimensional TCGA data and the known miRNAs involved in DDR to identify a miRNA-regulatory network that responds to DNA damage. Additionally, based on the expression of ten miRNAs in this network, we developed a 10-miRNA-score that predicts defects in the homologous recombination (HR) pathway and genome instability in ovarian cancer. Importantly, consistent with the association between HR defects and improved response to chemotherapeutic agents, the 10-miRNA-score predicts the outcome of ovarian cancer patients treated with platinum agents, with a surprisingly better performance than the indexes of DNA damage. Therefore, our study demonstrates the implication of miRNA expression on cancer genome instability and provides an alternative method to identify DDR defects in patients who show the best effect with platinum drug treatment.

MicroRNA in Glioblastoma: An Overview

Glioblastoma is the most aggressive brain tumor and, even with the current multimodal therapy, is an invariably lethal cancer with a life expectancy that depends on the tumor subtype but, even in the most favorable cases, rarely exceeds 2 years. Epigenetic factors play an important role in gliomagenesis, are strong predictors of outcome, and are important determinants for the resistance to radio- and chemotherapy. The latest addition to the epigenetic machinery is the noncoding RNA (ncRNA), that is, RNA molecules that are not translated into a protein and that exert their function by base pairing with other nucleic acids in a reversible and nonmutational mode. MicroRNAs (miRNA) are a class of ncRNA of about 22 bp that regulate gene expression by binding to complementary sequences in the mRNA and silence its translation into proteins. MicroRNAs reversibly regulate transcription through nonmutational mechanisms; accordingly, they can be considered as epigenetic effectors. In this review, we will discuss the role of miRNA in glioma focusing on their role in drug resistance and on their potential applications in the therapy of this tumor.

Histone acetyltransferase KAT8 is essential for mouse oocyte development by regulating reactive oxygen species levels

Proper oocyte development is crucial for female fertility and requires timely and accurate control of gene expression. K (lysine) acetyltransferase 8 (KAT8), an important component of the X chromosome dosage compensation system in Drosophila, regulates gene activity by acetylating histone H4 preferentially at lysine 16. To explore the function of KAT8 during mouse oocyte development, we crossed Kat8^flox/flox mice with Gdf9-Cre mice to specifically delete Kat8 in oocytes. Oocyte Kat8 deletion resulted in female infertility, with follicle development failure in the secondary and preantral follicle stages. RNA-seq analysis revealed that Kat8 deficiency in oocytes results in significant downregulation of antioxidant genes, with a consequent increase in reactive oxygen species. Intraperitoneal injection of the antioxidant N-acetylcysteine rescued defective follicle and oocyte development resulting from Kat8 deficiency. Chromatin immunoprecipitation assays indicated that KAT8 regulates antioxidant gene expression by direct binding to promoter regions. Taken together, our findings demonstrate that KAT8 is essential for female fertility by regulating antioxidant gene expression and identify KAT8 as the first histone acetyltransferase with an essential function in oogenesis.

miR-214 inhibits invasion and migration via downregulating GALNT7 in esophageal squamous cell cancer

Previous studies verified that miR-214 is of great significance in the invasion and migration of a variety of cancers. It has been demonstrated that UDP-N-acetyl-α-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase 7(GALNT7) is a putative target of miR-214. We performed this study to figure out how miR-214 and GALNT7 play their roles in the invasion and migration of esophageal squamous cell carcinoma (ESCC). The expression of miR-214 was significantly downregulated in tumors compared to the corresponding non-tumor tissues while GALNT7 showed an opposite tendency. The low expression of miR-214 and the high expression of GALNT7 were found positively correlated with poor tumor differentiation (P = 0.004), tumor invasion (P = 0.013), and lymph node metastasis (P = 0.012) in ESCC patients. Functional study demonstrated that overexpression of miR-214 or knockdown of GALNT7 could weaken invasive and migratory ability in Eca109, TE1, and KYSE150. Moreover, tumorigenicity assay showed us mice injected with cells containing miR-214 mimic or GALNT7 small interfering RNA formed substantially smaller tumors than that in miR-214 inhibitor group. Consequently, we concluded that miR-214 shows potential to be a diagnostic marker and therapeutic target in ESCC.

Dysregulation of ubiquitin ligases in cancer

Ubiquitin ligases (UBLs) are critical components of the ubiquitin proteasome system (UPS), which governs fundamental processes regulating normal cellular homeostasis, metabolism, and cell cycle in response to external stress signals and DNA damage. Among multiple steps of the UPS system required to regulate protein ubiquitination and stability, UBLs define specificity, as they recognize and interact with substrates in a temporally- and spatially-regulated manner. Such interactions are required for substrate modification by ubiquitin chains, which marks proteins for recognition and degradation by the proteasome or alters their subcellular localization or assembly into functional complexes. UBLs are often deregulated in cancer, altering substrate availability or activity in a manner that can promote cellular transformation. Such deregulation can occur at the epigenetic, genomic, or post-translational levels. Alterations in UBL can be used to predict their contributions, affecting tumor suppressors or oncogenes in select tumors. Better understanding of mechanisms underlying UBL expression and activities is expected to drive the development of next generation modulators that can serve as novel therapeutic modalities. This review summarizes our current understanding of UBL deregulation in cancer and highlights novel opportunities for therapeutic interventions.

Impact of Nutrition on Non-Coding RNA Epigenetics in Breast and Gynecological Cancer

Cancer is the second leading cause of death in females. According to the American Cancer Society, there are 327,660 new cases in breast and gynecological cancers estimated in 2014, placing emphasis on the need for cancer prevention and new cancer treatment strategies. One important approach to cancer prevention involves phytochemicals, biologically active compounds derived from plants. A variety of studies on the impact of dietary compounds found in cruciferous vegetables, green tea, and spices like curry and black pepper have revealed epigenetic changes in female cancers. Thus, an important emerging topic comprises epigenetic changes due to the modulation of non-coding RNA levels. Since it has been shown that non-coding RNAs such as microRNAs and long non-coding RNAs are aberrantly expressed in cancer, and furthermore are linked to distinct cancer phenotypes, understanding the effects of dietary compounds and supplements on the epigenetic modulator non-coding RNA is of great interest. This article reviews the current findings on nutrition-induced changes in breast and gynecological cancers at the non-coding RNA level.