Sex-steroid receptors in the diethylnitrosamine model of hepatocarcinogenesis: modifications by gonadal ablation and steroid replacement therapy

Hormone replacement therapy is associated with reduced hepatocellular carcinoma risk and improved survival in postmenopausal women with hepatitis B: A nationwide long-term population-based cohort study

Postmenopausal women with hepatitis B virus (HBV) infection are more likely to have accelerated liver fibrosis, eventually advancing to liver cirrhosis or hepatocellular carcinoma (HCC). The association between sex hormones and HBV-related HCC risk is unclear. We investigated whether hormone replacement therapy (HRT) is beneficial to postmenopausal women with HBV infection. This retrospective study selected the data of 44,465patients with HBV infection between January 2000 and December 2018 from Taiwan’s National Health Insurance Research Database. After excluding patients with preexisting liver diseases, liver cirrhosis, or liver malignancies, we grouped the remaining 10,474 patients by whether they had undergone HRT for at least 3 months (n = 5,638) and whether they had not received HRT (n = 4,836). After propensity score matching, we assigned 3080 patients to an HRT cohort and matched them (1:1) with those in a non-HRT cohort. The incidence of HCC (P < 0.022) and all-cause mortality rate (P < 0.001) were lower in the HRT cohort than in the non-HRT cohort. The liver cirrhosis risk was not significantly higher in the HRT cohort (P = 0.355). HRT is associated with reduced HCC risk and improved survival outcomes but is unrelated to liver cirrhosis development in postmenopausal women.

Nonalcoholic steatohepatitis-related hepatocellular carcinoma: is there a role for the androgen receptor pathway?

The epidemic of insulin resistance, obesity, and metabolic syndrome has led to the emergence of nonalcoholic steatohepatitis (NASH) as the most common cause of liver disease in the US. Patients with NASH are at an increased risk for hepatic disease-related morbidity and death, and chronic inflammation in NASH patients can lead to hepatocellular carcinoma (HCC). The prevalence of HCC is higher in males than in females, and genetic studies have identified androgen and androgen receptors (ARs) as partially responsible for the gender disparity in the development of liver disease and HCC. Although many factors are known to play important roles in the progression of inflammation in NASH patients, the role of androgen and AR in the progression of NASH to HCC has been understudied. This review summarizes the evidence for a potential role of androgen and the AR pathway in the development of NASH-related HCC and in the treatment of HCC. It has been proposed that AR plays a role in the progression of HCC: inhibitory roles in early stages of hepatocarcinogenesis and tumor-promoting roles in advanced stages. AR can be activated by several pathways, even in the absence of androgen. While AR has been explored as a potential therapeutic target in HCC, several clinical trials have failed to demonstrate a clinical benefit of antiandrogen drugs in HCC. This review discusses the potential reason for these observations and discuss the potential future trials design in this important setting.

Reproductive factors, exogenous hormone use and risk of hepatocellular carcinoma among US women: results from the Liver Cancer Pooling Project

BACKGROUND

Hepatocellular carcinoma (HCC) occurs less commonly among women than men in almost all regions of the world. The disparity in risk is particularly notable prior to menopause suggesting that hormonal exposures during reproductive life may be protective. Exogenous oestrogenic exposures such as oral contraceptives (OCs), however, have been reported to increase risk, suggesting that estrogens may be hepatocarcinogenic. To examine the effects of reproductive factors and exogenous hormones on risk, we conducted a prospective analysis among a large group of US women.

METHODS

In the Liver Cancer Pooling Project, a consortium of US-based cohort studies, data from 799,500 women in 11 cohorts were pooled and harmonised. Cox proportional hazards regression models were used to generate hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations of reproductive factors and exogenous hormones with HCC (n=248).

RESULTS

Bilateral oophorectomy was associated with a significantly increased risk of HCC (HR=2.67, 95% CI=1.22-5.85), which did not appear to be related to a shorter duration of exposure to endogenous hormones or to menopausal hormone therapy use. There was no association between OC use and HCC (HR=1.12, 95% CI=0.82-1.55). Nor were there associations with parity, age at first birth, age at natural menopause, or duration of fertility.

CONCLUSIONS

The current study suggests that bilateral oophorectomy increases the risk of HCC but the explanation for the association is unclear. There was no association between OC use and HCC risk. Examination of endogenous hormone levels in relation to HCC may help to clarify the findings of the current study.

Dehydroepiandrosterone-induces miR-21 transcription in HepG2 cells through estrogen receptor β and androgen receptor

Although oncomiR miR-21 is highly expressed in liver and overexpressed in hepatocellular carcinoma (HCC), its regulation is uncharacterized. We examined the effect of physiologically relevant nanomolar concentrations of dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEA-S) on miR-21 expression in HepG2 human hepatoma cells. 10nM DHEA and DHEA-S increase pri-miR-21 transcription in HepG2 cells. Dietary DHEA increased miR-21 in vivo in mouse liver. siRNA and inhibitor studies suggest that DHEA-S requires desulfation for activity and that DHEA-induced pri-miR-21 transcription involves metabolism to androgen and estrogen receptor (AR and ER) ligands. Activation of ERβ and AR by DHEA metabolites androst-5-ene-3,17-dione (ADIONE), androst-5-ene-3β,17β-diol (ADIOL), dihydrotestosterone (DHT), and 5α-androstane-3β,17β-diol (3β-Adiol) increased miR-21 transcription. DHEA-induced miR-21 increased cell proliferation and decreased Pdcd4 protein, a bona fide miR-21. Estradiol (E2) inhibited miR-21 expression via ERα. DHEA increased ERβ and AR recruitment to the miR-21 promoter within the VMP1/TMEM49 gene, with possible significance in hepatocellular carcinoma.

Androgen receptor enhances cell adhesion and decreases cell migration via modulating β1-integrin-AKT signaling in hepatocellular carcinoma cells

The androgen receptor (AR) has been shown to promote the initiation and development of hepatocellular carcinoma (HCC) during the early stage of the disease process and to suppress HCC cell invasion during the later stages of the disease. The mechanisms governing these dual yet opposite roles have yet to be elucidated. Using carcinogen-induced HCC in vivo mouse models and the in vitro human HCC cell line SKhep1, we found that knockout of AR in primary HCC cells led to a decrease in HCC cell focal adhesion capacity compared to cells from wildtype mice. Similar results were obtained after adding functional AR into human HCC SKhep1 cells. Further analysis revealed that the role AR plays in adhesion of HCC cells is governed, at least in part, by its ability to up-regulate β1-integrin and activate the PI3K/AKT pathway. We also found that AR-β1-integrin-mediated cell adhesion suppresses cell migration. Those findings indicate that the AR-β1-integrin-PI3K/AKT signaling pathway might play a role in the bimodal function of AR on cell adhesion and migration at the cellular level.

Androgen receptor roles in hepatocellular carcinoma, fatty liver, cirrhosis and hepatitis

Androgen/androgen receptor (AR) signaling plays important roles in normal liver function and in progression of liver diseases. In studies of noncancerous liver diseases, AR knockout mouse models of liver disease have revealed that androgen/AR signaling suppresses the development of steatosis, virus-related hepatitis, and cirrhosis. In addition, studies have shown that targeting AR in bone marrow-derived mesenchymal stem cells (BM-MSCs) improves their self-renewal and migration potentials, thereby increasing the efficacy of BM-MSC transplantation as a way to control the progression of cirrhosis. Androgen/AR signaling is known to be involved in the initiation of carcinogen- or hepatitis B virus-related hepatocellular carcinoma (HCC). However, studies have demonstrated that AR, rather than androgen, plays the dominant role in cancer initiation. Therefore, targeting AR might be an appropriate therapy for patients with early-stage HCC. In contrast, androgen/AR signaling has been shown to suppress metastasis of HCC in patients with late-stage disease. In addition, there is evidence that therapy comprising Sorafenib and agents that enhance the functional expression of AR may suppress the progression of late-stage HCC.

Activation of androgen receptor induces ID1 and promotes hepatocellular carcinoma cell migration and invasion

Androgen receptor (AR) activity is associated with cancer development and progression. In hepatocellular carcinoma (HCC), AR contributes to HCC incidence, but the role of AR in HCC cell migration and invasion remains largely unknown. In this study, we found that AR was expressed at high levels in a subgroup of HCC cell lines with high metastatic potential. Experiments using lentiviral overexpression or small hairpin RNA knockdown of AR as well as activation of AR by its ligand indicated that AR activation promoted HCC cell migration and invasion. We also found that AR activation enhanced the expression of a metastasis-promoting gene, ID1, which led to increased HCC cell migration and invasion. An AR antagonist was able to block this process, suggesting that AR activation in AR-positive HCC may be therapeutically inhibited as a potential intervention strategy.

Hepatic androgen receptor suppresses hepatocellular carcinoma metastasis through modulation of cell migration and anoikis

Early reports suggested androgen/androgen receptor (AR) signals promote hepatocarcinogenesis. However, all antiandrogen clinical trials failed in advanced hepatocellular carcinoma (HCC) without reasonable explanations. We examined AR functions in HCC cancer metastasis in this study. We examined hepatic AR roles in HCC metastasis by comparing liver hepatocyte AR knockout and wildtype in a carcinogen-induced HCC mouse model. We examined tumor histology, cancer metastatic risks, and cancer survival in vivo, as well as cell anoikis and migration using primary hepatic tumor culture in vitro. We also examined therapeutic potentials of AR expression combined with the molecular targeting agent sorafenib in an HCC metastasis mouse model. We found a novel cancer phenotype in which mice lacking hepatic AR developed more undifferentiated tumors and larger tumor size at the metastatic stage. These mice also died earlier with increased lung metastasis, suggesting that hepatic AR may play dual yet opposite roles to promote HCC initiation but suppress HCC metastasis. Mechanistic dissection found that hepatic AR could enhance anoikis and suppress migration of HCC cells by way of suppression of p38 phosphorylation/activation and the nuclear factor kappa B (NF-κB)/matrix metallopeptidase 9 (MMP9) pathway, respectively. In addition, the in vivo preclinical trials concluded that a combination therapy of increased AR expression and reduced multiple-kinase inhibitor (sorafenib) exhibited better therapeutic efficacy.

CONCLUSION

Our study demonstrates that AR could orchestrate intrahepatic signaling hierarchies and cellular behaviors, consequently affect HCC progression. Results from combination therapy shed light on developing new therapeutic paradigms for battling HCC at later metastatic stages.

Osteopontin is involved in estrogen-mediated protection against diethylnitrosamine-induced liver injury in mice

Diethylnitrosamine (DEN) is a potent hepatotoxin and hepatocarcinogen in animals and possible in humans. Estrogen has been reported to play a protective role against DEN exposure. Osteopontin (OPN), a downstream molecular of estrogen, plays a role in many pathophysiological processes. In this study, we evaluate the role of OPN in estrogen-mediated hepatoprotection in DEN-treated mice. DEN was administrated intraperitoneally to C57BL/6 and OPN(-/-) mice. Compared to male mice, female mice exhibited significantly higher hepatic OPN expression with less liver damage 48 h after DEN treatment. Interestingly, enhanced OPN expression was predominantly detected in hepatocytes after DEN treatment. OPN deficiency enhanced the susceptibility to DEN, which was more apparent in females than males. Estrogen-mediated protection against DEN in males was abrogated by OPN deficiency. The protective activities of estrogen could be mimicked by exogenous OPN. Consistent with liver injury, oxidative stress in liver was enhanced with OPN depletion. OPN reduced DEN-induced oxidative stress likely through inhibition of CYP2A5 expression. In conclusion, we demonstrate that OPN may be involved in estrogen-mediated hepatoprotection in DEN-induced liver injury through enhancement of hepatocyte survival and inhibition of DEN biotransformation. Our findings may provide new insight into gender differences in chemical-induced liver injury and related diseases.

Role of sex steroid receptors in pathobiology of hepatocellular carcinoma

The striking gender disparity observed in the incidence of hepatocellular carcinoma (HCC) suggests an important role of sex hormones in HCC pathogenesis. Though the studies began as early as in 1980s, the precise role of sex hormones and the significance of their receptors in HCC still remain poorly understood and perhaps contribute to current controversies about the potential use of hormonal therapy in HCC. A comprehensive review of the existing literature revealed several shortcomings associated with the studies on estrogen receptor (ER) and androgen receptor (AR) in normal liver and HCC. These shortcomings include the use of less sensitive receptor ligand binding assays and immunohistochemistry studies for ERα alone until 1996 when ERβ isoform was identified. The animal models of HCC utilized for studies were primarily based on chemical-induced hepatocarcinogenesis with less similarity to virus-induced HCC pathogenesis. However, recent in vitro studies in hepatoma cells provide newer insights for hormonal regulation of key cellular processes including interaction of ER and AR with viral proteins. In light of the above facts, there is an urgent need for a detailed investigation of sex hormones and their receptors in normal liver and HCC. In this review, we systematically present the information currently available on androgens, estrogens and their receptors in normal liver and HCC obtained from in vitro, in vivo experimental models and clinical studies. This information will direct future basic and clinical research to bridge the gap in knowledge to explore the therapeutic potential of hormonal therapy in HCC.

Androgen receptor is a new potential therapeutic target for the treatment of hepatocellular carcinoma

BACKGROUND & AIMS

Androgen effects on hepatocellular carcinoma (HCC) remain controversial and androgen ablation therapy to treat HCC also leads to inconsistent results. Here we examine androgen receptor (AR) roles in hepatocarcinogenesis using mice lacking AR in hepatocytes.

METHODS

By using the Cre-Lox conditional knockout mice model injected with carcinogen, we examined the AR roles in hepatocarcinogenesis. We also tested the possible roles of AR in cellular oxidative stress and DNA damage sensing/repairing systems. By using AR degrading compound, ASC-J9, or AR-small interference RNA, we also examined the therapeutic potentials of targeting AR in HCC.

RESULTS

We found AR expression was increased in human HCC compared with normal livers. We also found mice lacking hepatic AR developed later and less HCC than their wild-type littermates with comparable serum testosterone in both male and female mice. Addition of functional AR in human HCC cells also resulted in the promotion of cell growth in the absence or presence of 5alpha-dihydrotestosterone. Mechanistic dissection suggests that AR may promote hepatocarcinogenesis via increased cellular oxidative stress and DNA damage, as well as suppression of p53-mediated DNA damage sensing/repairing system and cell apoptosis. Targeting AR directly via either AR-small interference RNA or ASC-J9 resulted in suppression of HCC in both ex vivo cell lines and in vivo mice models.

CONCLUSIONS

Our data point to AR, but not androgens, as a potential new and better therapeutic target for the battle of HCC.