The male-specific factor Sry harbors an oncogenic function

Sex-determining region Y gene promotes liver fibrosis and accounts for sexual dimorphism in its pathophysiology

BACKGROUND & AIMS

Men are more prone to develop and die from liver fibrosis than women. In this study, we aim to investigate how sex-determining region Y gene (SRY) in hepatocytes promotes liver fibrosis.

METHODS

Hepatocyte-specific Sry knock-in (KI), Sry knockout (KO), and Sry KI with platelet-derived growth factor receptor α (Pdgfrα) KO mice were generated. Liver fibrosis was induced in mice by bile duct ligation for 2 weeks or carbon tetrachloride treatment for 6 weeks. In addition, primary hepatocytes, hepatic stellate cells (HSCs), and immortalized cell lines were used for in vitro studies and mechanistic investigation.

RESULTS

Compared to females, the severity of toxin- or cholestasis-induced liver fibrosis is similarly increased in castrated and uncastrated male mice. Among all Y chromosome-encoded genes, SRY was the most significantly upregulated and consistently increased gene in fibrotic/cirrhotic livers in male patients and in mouse models. Sry KI mice developed exacerbated liver fibrosis, whereas Sry KO mice had alleviated liver fibrosis, compared to age- and sex-matched control mice after bile duct ligation or administration of carbon tetrachloride. Mechanistically, both our in vivo and in vitro studies illustrated that SRY in hepatocytes can transcriptionally regulate Pdgfrα expression, and promote HMGB1 (high mobility group box 1) release and subsequent HSC activation. Pdgfrα KO or treatment with the SRY inhibitor DAX1 in Sry KI mice abolished SRY-induced HMGB1 secretion and liver fibrosis.

CONCLUSIONS

SRY is a strong pro-fibrotic factor and accounts for the sex disparity observed in liver fibrosis, suggesting its critical role as a potentially sex-specific therapeutic target for prevention and treatment of the disease.

IMPACT AND IMPLICATION

We identified that a male-specific gene, sex-determining region Y gene (SRY), is a strong pro-fibrotic gene that accounts for the sex disparity observed in liver fibrosis. As such, SRY might be an appropriate target for surveillance and treatment of liver fibrosis in a sex-specific manner. Additionally, SRY might be a key player in the sexual dimorphism observed in hepatic pathophysiology more generally.

Mosaic loss of the Y chromosome in human neurodegenerative and oncological diseases

The development of new biomarkers for prediction and early detection of human diseases, as well as for monitoring the response to therapy is one of the most relevant areas of modern human genetics and genomics. Until recently, it was believed that the function of human Y chromosome genes was limited to determining sex and controlling spermatogenesis. Thanks to occurance of large databases of the genome-wide association study (GWAS), there has been a transition to the use of large samples for analyzing genetic changes in both normal and pathological conditions. This has made it possible to assess the association of mosaic aneuploidy of the Y chromosome in somatic cells with a shorter lifespan in men compared to women. Based on data from the UK Biobank, an association was found between mosaic loss of the Y chromosome (mLOY) in peripheral blood leukocytes and the age of men over 70, as well as a number of oncological, cardiac, metabolic, neurodegenerative, and psychiatric diseases. As a result, mLOY in peripheral blood cells has been considered a potential marker of biological age in men and as a marker of certain age-related diseases. Currently, numerous associations have been identified between mLOY and genes based on GWAS and transcriptomes in affected tissues. However, the exact cause of mLOY and the impact and consequences of this phenomenon at the whole organism level have not been established. In particular, it is unclear whether aneuploidy of the Y chromosome in blood cells may affect the development of pathologies that manifest in other organs, such as the brain in Alzheimer's disease, or whether it is a neutral biomarker of general genomic instability. This review examines the main pathologies and genetic factors associated with mLOY, as well as the hypotheses regarding their interplay. Special attention is given to recent studies on mLOY in brain cells in Alzheimer's disease.

Sex specific regulation of TSPY-Like 2 in the DNA damage response of cancer cells

Females have a lower probability to develop somatic cancers and a better response to chemotherapy than males. However, the reasons for these differences are still not well understood. The X-linked gene TSPY-Like 2 (TSPYL2) encodes for a putative tumor suppressor protein involved in cell cycle regulation and DNA damage response (DDR) pathways. Here, we demonstrate that in unstressed conditions TSPYL2 is maintained at low levels by MDM2-dependent ubiquitination and proteasome degradation. Upon genotoxic stress, E2F1 promotes TSPYL2 expression and protein accumulation in non-transformed cell lines. Conversely, in cancer cells, TSPYL2 accumulates only in females or in those male cancer cells that lost the Y-chromosome during the oncogenic process. Hence, we demonstrate that while TSPYL2 mRNA is induced in all the tested tumor cell lines after DNA damage, TSPYL2 protein stability is increased only in female cancer cells. Indeed, we found that TSPYL2 accumulation, in male cancer cells, is prevented by the Y-encoded protein SRY, which modulates MDM2 protein levels. In addition, we demonstrated that TSPYL2 accumulation is required to sustain cell growth arrest after DNA damage, possibly contributing to protect normal and female cancer cells from tumor progression. Accordingly, TSPYL2 has been found more frequently mutated in female-specific cancers. These findings demonstrate for the first time a sex-specific regulation of TSPYL2 in the DDR of cancer cells and confirm the existence of sexual dimorphism in DNA surveillance pathways.

Comprehensive analysis of histone methylation modification regulators for predicting prognosis and drug sensitivity in lung adenocarcinoma

Histone methylation is an epigenetic modification regulated by histone methyltransferases, histone demethylases, and histone methylation reader proteins that play important roles in the pathogenic mechanism of cancers. However, the prognostic value of histone methylation in lung adenocarcinoma (LUAD) remains unknown. Here, we found that LUAD cases could be divided into 2 subtypes by the 144 histone methylation modification regulators (HMMRs), with a significant difference in OS time. Ninety-five of the HMMRs were identified as differentially expressed genes (DEGs) between normal and tumor samples, and 13 of them were further discovered to be survival-related genes (SRGs). By applying the least absolute shrinkage and selector operator (LASSO) Cox regression, we constructed an 8-gene-based risk signature according to the TCGA (training) cohort, and the risk score calculated by the signature was proven to be an independent factor in both the training and validation cohorts. We then discovered that the immune functions were generally impaired in the high-risk groups defined by the HMMR signature (especially for the DCs and immune check-point pathway). Functional analyses showed that the DEGs between the low- and high-risk groups were related to the cell cycle. The drug sensitivity analysis indicated that our risk model could predict the sensitivity of commonly used drugs. Moreover, according to the DEGs between the low- and high-risk groups, we discovered several new compounds that showed potential therapeutic value for high-risk LUAD patients. In conclusion, our study demonstrated that HMMRs were promising predictors for the prognoses and drug therapeutic effects for LUAD patients.

Sex-limited chromosomes and non-reproductive traits

Sex chromosomes are typically viewed as having originated from a pair of autosomes, and differentiated as the sex-limited chromosome (e.g. Y) has degenerated by losing most genes through cessation of recombination. While often thought that degenerated sex-limited chromosomes primarily affect traits involved in sex determination and sex cell production, accumulating evidence suggests they also influence traits not sex-limited or directly involved in reproduction. Here, we provide an overview of the effects of sex-limited chromosomes on non-reproductive traits in XY, ZW or UV sex determination systems, and discuss evolutionary processes maintaining variation at sex-limited chromosomes and molecular mechanisms affecting non-reproductive traits.

Recruitment of DNA to tumor-derived microvesicles

The shedding of extracellular vesicles (EVs) represents an important but understudied means of cell-cell communication in cancer. Among the currently described classes of EVs, tumor-derived microvesicles (TMVs) comprise a class of vesicles released directly from the cell surface. TMVs contain abundant cargo, including functional proteins and miRNA, which can be transferred to and alter the behavior of recipient cells. Here, we document that a fraction of extracellular double-stranded DNA (dsDNA) is enclosed within TMVs and protected from nuclease degradation. dsDNA inclusion in TMVs is regulated by ARF6 cycling and occurs with the cytosolic DNA sensor, cGAS, but independent of amphisome or micronuclei components. Our studies suggest that dsDNA is trafficked to TMVs via a mechanism distinct from the multivesicular body-dependent secretion reported for the extracellular release of cytosolic DNA. Furthermore, TMV dsDNA can be transferred to recipient cells with consequences to recipient cell behavior, reinforcing its relevance in mediating cell-cell communication.

Advance of SOX Transcription Factors in Hepatocellular Carcinoma: From Role, Tumor Immune Relevance to Targeted Therapy

Simple Summary

Hepatocellular carcinoma (HCC) is one of the deadliest human health burdens worldwide. However, the molecular mechanism of HCC development is still not fully understood. Sex determining region Y-related high-mobility group box (SOX) transcription factors not only play pivotal roles in cell fate decisions during development but also participate in the initiation and progression of cancer. Given the significance of SOX factors in cancer and their ‘undruggable’ properties, we summarize the role and molecular mechanism of SOX family members in HCC and the regulatory effect of SOX factors in the tumor immune microenvironment (TIME) of various cancers. For the first time, we analyze the association between the levels of SOX factors and that of immune components in HCC, providing clues to the pivotal role of SOX factors in the TIME of HCC. We also discuss the opportunities and challenges of targeting SOX factors for cancer.

Abstract

Sex determining region Y (SRY)-related high-mobility group (HMG) box (SOX) factors belong to an evolutionarily conserved family of transcription factors that play essential roles in cell fate decisions involving numerous developmental processes. In recent years, the significance of SOX factors in the initiation and progression of cancers has been gradually revealed, and they act as potential therapeutic targets for cancer. However, the research involving SOX factors is still preliminary, given that their effects in some leading-edge fields such as tumor immune microenvironment (TIME) remain obscure. More importantly, as a class of ‘undruggable’ molecules, targeting SOX factors still face considerable challenges in achieving clinical translation. Here, we mainly focus on the roles and regulatory mechanisms of SOX family members in hepatocellular carcinoma (HCC), one of the fatal human health burdens worldwide. We then detail the role of SOX members in remodeling TIME and analyze the association between SOX members and immune components in HCC for the first time. In addition, we emphasize several alternative strategies involved in the translational advances of SOX members in cancer. Finally, we discuss the alternative strategies of targeting SOX family for cancer and propose the opportunities and challenges they face based on the current accumulated studies and our understanding.

Alternate Roles of Sox Transcription Factors beyond Transcription Initiation

Sox proteins are known as crucial transcription factors for many developmental processes and for a wide range of common diseases. They were believed to specifically bind and bend DNA with other transcription factors and elicit transcriptional activation or repression activities in the early stage of transcription. However, their functions are not limited to transcription initiation. It has been showed that Sox proteins are involved in the regulation of alternative splicing regulatory networks and translational control. In this review, we discuss the current knowledge on how Sox transcription factors such as Sox2, Sry, Sox6, and Sox9 allow the coordination of co-transcriptional splicing and also the mechanism of SOX4-mediated translational control in the context of RNA polymerase III.

Deletions on Chromosome Y and Downregulation of the SRY Gene in Tumor Tissue Are Associated with Worse Survival of Glioblastoma Patients

BACKGROUND

Biological causes of sex disparity seen in the prevalence of cancer, including glioblastoma (GBM), remain poorly understood. One of the considered aspects is the involvement of the sex chromosomes, especially loss of chromosome Y (LOY).

METHODS

Tumors from 105 isocitrate dehydrogenase (IDH) wild type male GBM patients were tested with droplet digital PCR for copy number changes of ten genes on chromosome Y. Decreased gene expression, a proxy of gene loss, was then analyzed in 225 IDH wild type GBM derived from TCGA and overall survival in both cohorts was tested with Kaplan-Meier log-rank analysis and maximally selected rank statistics for cut-off determination.

RESULTS

LOY was associated with significantly shorter overall survival (7 vs. 14.6 months, p = 0.0016), and among investigated individual genes survival correlated most prominently with loss of the sex-determining region Y gene (SRY) (10.8 vs. 14.8 months, p = 0.0031). Gene set enrichment analysis revealed that epidermal growth factor receptor, platelet-derived growth factor receptor, and MYC proto-oncogene signaling pathways are associated with low SRY expression.

CONCLUSION

Our data show that deletions and reduced gene expression of chromosome Y genes, especially SRY, are associated with reduced survival of male GBM patients and connected to major susceptibility pathways of gliomagenesis.

Let's Talk About Sex-Biological Sex Is Underreported in Biomaterial Studies

Precision medicine aims to better individualize healthcare. It requires that biomaterials be designed for the physiological characteristics of a specific patient. To make this a reality, biomaterials research and development must address differences of biological sex. More specifically, biomaterials should be designed with properties optimized and appropriate for male and female patients. In analyzing research articles from seven prominent biomaterials journals, sex as a biological variable is missing from an overwhelming majority of in vitro biomaterial studies. From the survey, the reporting of the sex of primary cell cultures happened only 10.3% of the time. Contributing to this trend is that commercial vendors bias cell lines toward one sex or another by not disclosing information of cell line sex at the time of purchase; researchers do not communicate this pertinent information in published studies; and many journal policies have little to no requirements for reporting cell line characteristics. Omitting this valuable information leads to a gap in the understanding of sex-specific cell-biomaterial interactions and it creates a bias in research findings towards one sex or another. To curb this concerning trend and make precision biomaterials a reality will require the biomaterials field to "talk about sex" by reporting cell sex more broadly.

Recent advances in the molecular mechanism of sex disparity in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is more frequently observed and aggressive in men compared with women. Increasing evidence demonstrates that the sex disparity appears to be mediated by the stimulatory effects of androgens and the protective effects of estrogen in the development and progression of HCC. In the past few decades, studies on the sex difference of HCC mainly focused on the effect of sex hormones on the transactivation of hepatitis B virus X protein and the release of inflammatory cytokines, and these studies have further intensified in recent years. Sex hormones are also involved in genetic alterations and DNA damage repair in hepatocytes through binding to their specific cellular receptors and affecting the corresponding signaling pathways. Furthermore, the theory of sex chromosomes participating in HCC has been considered. The present review discussed the recent advances in the molecular mechanisms of sex disparity in HCC, with the aim of improving the understanding of the underlying critical factors and exploring more effective methods for the prevention and treatment of HCC.

Sexual dimorphism in hepatitis B and C and hepatocellular carcinoma

The incidence of viral hepatitis B or C (HBV/HCV) infection and hepatocellular carcinoma is higher in male compared to female populations, showing a faster disease progression and results in a worse overall survival. Indeed, women are in general better protected from viral infections and show a lower risk of death from malignant cancer in comparison to men. Females mount stronger innate and adaptive immune responses than males, and therefore, most of the autoimmune diseases occur predominantly in females. Next to occupational and/or behavioral factors, cellular and molecular differences between the two sexes contribute to this observation. In this review, we will discuss underlying mechanisms that are important for the observed sex-related differences in liver diseases. A better appreciation of these differences between the two sexes might be of value for better and gender-specific treatment options.

Activation of SRY accounts for male-specific hepatocarcinogenesis: Implication in gender disparity of hepatocellular carcinoma

Sex affects the risk, treatment responses and outcome of many types of cancers. The mechanism of gender disparity in development of hepatocellular carcinoma (HCC) remains obscure. Sex-determining region on Y chromosome (SRY) was overexpressed in approximate 84% male patient HCC. Moreover, we are the first to generate a liver-specific transgenic (TG) murine model with overexpression of the male specific gene SRY. Subject to a single intraperitoneal injection N-nitrosodiethylamine (DEN) at day 14, TG and wildtype (WT) mice of both genders were sacrificed at different time points (6-13.5 months). Overexpression of SRY in male TG and ectopic expression of SRY in female TG livers promoted DEN-induced hepatocarcinogenesis compared to age- and sex-matched WT. This accelerated tumorigenesis in TG of both genders was a consequence of increased injury and inflammation, fibrosis, and compensatory enhancement in hepatocytes proliferation secondary to activation of downstream targets Sox9 and platelet-derived growth factor receptor α (PDGFRα)/phosphoinositide 3-kinase (PI3K)/Akt and c-myc/CyclinD1. In conclusion, activation of SRY and its downstream Sox9 and PDGFRα pathways are commonly involved in male hepatocarcinogenesis, which provides novel insights into gender disparity and sex-specific therapeutic strategies of HCC.

Sexual dimorphism in cancer

The incidence of many types of cancer arising in organs with non-reproductive functions is significantly higher in male populations than in female populations, with associated differences in survival. Occupational and/or behavioural factors are well-known underlying determinants. However, cellular and molecular differences between the two sexes are also likely to be important. In this Opinion article, we focus on the complex interplay that sex hormones and sex chromosomes can have in intrinsic control of cancer-initiating cell populations, the tumour microenvironment and systemic determinants of cancer development, such as the immune system and metabolism. A better appreciation of these differences between the two sexes could be of substantial value for cancer prevention as well as treatment.

JARID1D Is a Suppressor and Prognostic Marker of Prostate Cancer Invasion and Metastasis

Entire or partial deletions of the male-specific Y chromosome are associated with tumorigenesis, but whether any male-specific genes located on this chromosome play a tumor-suppressive role is unknown. Here, we report that the histone H3 lysine 4 (H3K4) demethylase JARID1D (also called KDM5D and SMCY), a male-specific protein, represses gene expression programs associated with cell invasiveness and suppresses the invasion of prostate cancer cells in vitro and in vivo. We found that JARID1D specifically repressed the invasion-associated genes MMP1, MMP2, MMP3, MMP7, and Slug by demethylating trimethyl H3K4, a gene-activating mark, at their promoters. Our additional results demonstrated that JARID1D levels were highly downregulated in metastatic prostate tumors compared with normal prostate tissues and primary prostate tumors. Furthermore, the JARID1D gene was frequently deleted in metastatic prostate tumors, and low JARID1D levels were associated with poor prognosis in prostate cancer patients. Taken together, these findings provide the first evidence that an epigenetic modifier expressed on the Y chromosome functions as an anti-invasion factor to suppress the progression of prostate cancer. Our results also highlight a preclinical rationale for using JARID1D as a prognostic marker in advanced prostate cancer.

SGF29 and Sry pathway in hepatocarcinogenesis

Deregulated c-Myc expression is a hallmark of many human cancers. We have recently identified a role of mammalian homolog of yeast SPT-ADA-GCN5-acetyltransferas (SAGA) complex component, SAGA-associated factor 29 (SGF29), in regulating the c-Myc overexpression. Here, we discuss the molecular nature of SFG29 in SPT3-TAF9-GCN5-acetyltransferase complex, a counterpart of yeast SAGA complex, and the mechanism through which the elevated SGF29 expression contribute to oncogenic potential of c-Myc in hepatocellularcarcinoma (HCC). We propose that the upstream regulation of SGF29 elicited by sex-determining region Y (Sry) is also augmented in HCC. We hypothesize that c-Myc elevation driven by the deregulated Sry and SGF29 pathway is implicated in the male specific acquisition of human HCCs.

SRY and OCT4 Are Required for the Acquisition of Cancer Stem Cell-Like Properties and Are Potential Differentiation Therapy Targets

The acquisition of stemness is a hallmark of aggressive human hepatocellular carcinoma (hHCC). The stem cell marker OCT4 is frequently expressed in HCCs, and its expression correlates with those of putative cancer stem cell (CSC) markers and CSC properties. Here, we describe a novel mechanism of CSC maintenance by SRY through OCT4. We previously reported that Sry is involved in tumor malignancy in rodent HCCs. However, the oncogenic function of SRY in hHCCs is poorly understood. Ectopic expression of SRY increased multiple stem cell factors, including OCT4 and CD13. The OCT4 promoter contained SRY-binding sites that were directly activated by SRY. In HCC-derived cells, SRY knockdown decreased OCT4 expression and cancer stem-like phenotypes such as self-renewal, chemoresistance, and tumorigenicity. Conversely, OCT4 and SRY overexpression promoted cancer stem-like phenotypes. OCT4 knockdown in SRY clones downregulated the self-renewal capacity and chemoresistance. These data suggest that SRY is involved in the maintenance of cancer stem-like characteristics through OCT4. Moreover, CSCs of HCC-derived cells differentiated into Tuj1-positive neuron-like cells by retinoic acid. Noteworthily, SRY was highly expressed in some hHCC patients. Taken together, our findings imply a novel therapeutic strategy against CSCs of hHCCs.

Functions of SAGA in development and disease

Precise regulation of gene expression programs during embryo development requires cooperation between transcriptional factors and histone-modifying enzymes, such as the Gcn5 histone acetyltransferase. Gcn5 functions within a multi-subunit complex, called SAGA, that is recruited to specific genes through interactions with sequence-specific DNA-binding proteins to aid in gene activation. Although the transcriptional programs regulated by SAGA in embryos are not well defined, deletion of either Gcn5 or USP22, the catalytic subunit of a deubiquitinase module in SAGA, leads to early embryonic lethality. Here, we review the known functions of Gcn5, USP22 and associated proteins during development and discuss how these functions might be related to human disease states, including cancer and neurodegenerative diseases.