Sex-determination gene SRY potentially associates with poor prognosis but not sex bias in hepatocellular carcinoma

Diverse functions of SOX9 in liver development and homeostasis and hepatobiliary diseases

The liver is the central organ for digestion and detoxification and has unique metabolic and regenerative capacities. The hepatobiliary system originates from the foregut endoderm, in which cells undergo multiple events of cell proliferation, migration, and differentiation to form the liver parenchyma and ductal system under the hierarchical regulation of transcription factors. Studies on liver development and diseases have revealed that SRY-related high-mobility group box 9 (SOX9) plays an important role in liver embryogenesis and the progression of hepatobiliary diseases. SOX9 is not only a master regulator of cell fate determination and tissue morphogenesis, but also regulates various biological features of cancer, including cancer stemness, invasion, and drug resistance, making SOX9 a potential biomarker for tumor prognosis and progression. This review systematically summarizes the latest findings of SOX9 in hepatobiliary development, homeostasis, and disease. We also highlight the value of SOX9 as a novel biomarker and potential target for the clinical treatment of major liver diseases.

The role of sex hormones and receptors in HBV infection and development of HBV-related HCC

Gender disparity in hepatitis B virus (HBV)-related diseases has been extensively documented. Epidemiological studies consistently reported that males have a higher prevalence of HBV infection and incidence of hepatocellular carcinoma (HCC). Further investigations have revealed that sex hormone-related signal transductions play a significant role in gender disparity. Sex hormone axes showed significantly different responses to virus entry and replication. The sex hormones axes change the HBV-specific immune responses and antitumor immunity. Additionally, Sex hormone axes showed different effects on the development of HBV-related disease. But the role of sex hormones remains controversial, and researchers have not reached a consensus on the role of sex hormones and the use of hormone therapies in HCC treatment. In this review, we aim to summarize the experimental findings on sex hormones and provide a comprehensive understanding of their roles in the development of HCC and their implications for hormone-related HCC treatment.

Gender Differences in the Pathogenesis and Risk Factors of Hepatocellular Carcinoma

Several chronic liver diseases are characterized by a clear gender disparity. Among them, hepatocellular carcinoma (HCC) shows significantly higher incidence rates in men than in women. The different epidemiological distribution of risk factors for liver disease and HCC only partially accounts for these gender differences. In fact, the liver is an organ with recognized sexual dysmorphism and is extremely sensitive to the action of androgens and estrogens. Sex hormones act by modulating the risk of developing HCC and influencing its aggressiveness, response to treatments, and prognosis. Furthermore, androgens and estrogens are able to modulate the action of other factors and cofactors of liver damage (e.g., chronic HBV infection, obesity), significantly influencing their carcinogenic power. The purpose of this review is to examine the factors related to the different gender distribution in the incidence of HCC as well as the pathophysiological mechanisms involved, with particular reference to the central role played by sex hormones.

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.

Clinical implications of cancer stem cells in digestive cancers: acquisition of stemness and prognostic impact

Digestive system cancers are the most frequent cancers worldwide and often associated with poor prognosis because of their invasive and metastatic characteristics. Recent studies have found that the plasticity of cancer cells can impart cancer stem-like properties via the epithelial-mesenchymal transition (EMT). Cancer stem-like properties such as tumor initiation are integral to the formation of metastasis, which is the main cause of poor prognosis. Numerous markers of cancer stem cells (CSCs) have been identified in many types of cancer. Therefore, CSCs, via their stem cell-like functions, may play an important role in prognosis after surgery. While several reports have described prognostic analysis using CSC markers, few reviews have summarized CSCs and their association with prognosis. Herein, we review the prognostic potential of eight CSC markers, CD133, CD44, CD90, ALDH1A1, EPCAM, SOX2, SOX9, and LGR5, in digestive cancers including those of the pancreas, colon, liver, gastric, and esophagus.

SOX9 Stem-Cell Factor: Clinical and Functional Relevance in Cancer

Transcriptional and epigenetic embryonic programs can be reactivated in cancer cells. As result, a specific subset of undifferentiated cells with stem-cells properties emerges and drives tumorigenesis. Recent findings have shown that ectoderm- and endoderm-derived tissues continue expressing stem-cells related transcription factors of the SOX-family of proteins such as SOX2 and SOX9 which have been implicated in the presence of cancer stem-like cells (CSCs) in tumors. Currently, there is enough evidence suggesting an oncogenic role for SOX9 in different types of human cancers. This review provides a summary of the current knowledge about the involvement of SOX9 in development and progression of cancer. Understanding the functional roles of SOX9 and clinical relevance is crucial for developing novel treatments targeting CSCs in cancer.

SOX9 is a proliferation and stem cell factor in hepatocellular carcinoma and possess widespread prognostic significance in different cancer types

SOX9 has been previously shown to be involved in hepatocellular carcinoma (HCC) and other types of cancer. However, prognostic studies so far involved rather small cohorts or lack external validation and experimental data. In this study, we firstly determined the histological expression pattern of SOX9 in human HCC by immunohistochemistry (n = 84) and evaluated its prognostic value. External cohorts of publicly available datasets were used to validate its prognostic relevance in HCC (n = 359) and other types of cancer including breast (n = 3951), ovarian (n = 1306), lung (n = 1926) and gastric cancer (n = 876). Functional SOX9 knock-down studies using siRNA and cancer stem cell models were generated in a panel of liver and breast cancer cell lines. High level of SOX9 was associated with poor survival even after adjustment for other prognostic factors in multivariate analysis (HR = 2.103, 95%CI = 1.064 to 4.156, p = 0.021). SOX9 prevailed a poor prognostic factor in all cancer validation cohorts (p<0.05). Reduced SOX9 expression by siRNA decreased the growth of liver cancer cells (p<0.05). SOX9 expression was associated with stem cell features in all tested cell lines (p<0.05). In conclusion, this study demonstrated in a large number of patients from multiple cohorts that high levels of SOX9 are a consistent negative prognostic factor.

Upregulated SOX9 expression indicates worse prognosis in solid tumors: a systematic review and meta-analysis

It was recently reported that increased SOX9 expression drives tumor growth and promotes cancer invasion during human tumorigenicity and metastasis. However, the prognostic value of SOX9 for the survival of patients with solid tumors remains controversial. The present meta-analysis was thus performed to highlight the link between dysregulated SOX9 expression and prognosis in cancer patients. A systematic literature search was conducted using the electronic databases PubMed, Web of Science and Embase to identify eligible studies. A random-effects meta-analytical model was employed to correlate SOX9 expression with overall survival (OS), disease-free survival (DFS) and clinicopathological features. In total, 17 studies with 3307 patients were eligible for the final analysis. Combined hazard ratios (HRs) and 95% confidence intervals (CIs) suggested that high SOX9 expression has an unfavourable impact on OS (HR = 1.66, 95% CI 1.36-2.02, P < 0.001) and DFS (HR = 3.54, 95% CI 2.29-5.47, P = 0.008) in multivariate analysis. Additionally, the pooled odds ratios (ORs) indicated that SOX9 over-expression is associated with large tumor size, lymph node metastasis, distant metastasis and a higher clinical stage. Overall, these results indicated that SOX9 over-expression in patients with solid tumors might be related to poor prognosis and could serve as a potential predictive marker of poor clinicopathological prognosis factor.

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.

CircRNAs: a regulator of cellular stress

Circular RNAs (CircRNAs) were first identified as a viroid and later found to also be an endogenous RNA splicing product in eukaryotes. In recent years, a series of RNA-sequencing analyses from a diverse range of eukaryotes have shed new light on these eukaryotic circRNAs, revealing dynamic expression patterns in various developmental stages and physiological conditions. In this review, we focus on circRNAs implicated in stress response pathways and explore potential mechanisms underlying their regulation. To date, circRNAs have been shown to act as scaffolds in the assembly of protein complexes, sequester proteins from native subcellular localization, activate transcription of parental genes, inhibit RNA-protein interactions, and function as regulators of microRNA activity. Although the mechanism modulating circRNA levels during stress remains unclear, circRNAs are shown to be regulated during biogenesis, degradation, and exportation. As circRNAs do not have 5' and 3' ends, there are no entry points for exoribonucleases to initiate degradation. Such inherent stability makes this class of RNA a strong candidate to maintain homeostasis in the face of environmental challenges.

Alpha-fetoprotein-L3 and Golgi protein 73 may serve as candidate biomarkers for diagnosing alpha-fetoprotein-negative hepatocellular carcinoma

Currently, there is no reliable biomarker for use in diagnosing alpha-fetoprotein (AFP)-negative hepatocellular carcinoma (HCC). Such a biomarker would aid in making an early diagnosis of AFP-negative HCC, ensuring the timely initiation of treatment. This study examined AFP-L3 and Golgi protein 73 (GP73) as candidate biomarkers for AFP-negative HCC. The affinity adsorption method and enzyme-linked immunoassays were separately used to determine serum levels of AFP-L3 and GP73 in 50 patients with AFP-negative HCC, 30 non-HCC patients, and 50 healthy subjects. Fifty percent of patients with AFP-negative HCC tested positive for AFP-L3, while 3.33% of non-HCC patients and 2.00% of healthy subjects were AFP-L3 positive. Patients with AFP-negative HCC had significantly higher serum levels of AFP-L3 compared to non-HCC patients and healthy individuals; however, there was no significant difference in the AFP-L3 levels of non-HCC patients and healthy subjects. Sixty-six percent of patients with AFP-negative HCC tested positive for GP73, while 10% of non-HCC patients and 0% of healthy subjects were GP73-positive. Patients with AFP-negative HCC had significantly higher serum levels of GP73 compared to non-HCC patients and healthy subjects, but there was no significant difference between the GP73 levels of non-HCC patients and healthy individuals. Moreover, 20 patients with AFP-negative HCC were both AFP-L3- and GP73-positive, while no non-HCC patients or healthy subjects tested positive for both markers. Either AFP-L3 or GP73 may be used as a biomarker for diagnosing AFP-negative HCC, while their combined use provides improved diagnostic accuracy and greater sensitivity.