Effect of D-tryptophan-6-luteinizing hormone-releasing hormone on the tumoral growth and plasma sex steroid levels in cirrhotic patients with hepatocellular carcinoma

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.

Molecular Immune Mechanism of Intestinal Microbiota and Their Metabolites in the Occurrence and Development of Liver Cancer

Intestinal microorganisms are closely associated with immunity, metabolism, and inflammation, and play an important role in health and diseases such as inflammatory bowel disease, diabetes, cardiovascular disease, Parkinson’s disease, and cancer. Liver cancer is one of the most fatal cancers in humans. Most of liver cancers are slowly transformed from viral hepatitis, alcoholic liver disease, and non-alcoholic fatty liver disease. However, the relationship between intestinal microbiota and their metabolites, including short-chain fatty acids, bile acids, indoles, and ethanol, and liver cancer remains unclear. Here, we summarize the molecular immune mechanism of intestinal microbiota and their metabolites in the occurrence and development of liver cancer and reveal the important role of the microbiota-gut-liver axis in liver cancer. In addition, we describe how the intestinal flora can be balanced by antibiotics, probiotics, postbiotics, and fecal bacteria transplantation to improve the treatment of liver cancer. This review describes the immunomolecular mechanism of intestinal microbiota and their metabolites in the occurrence and development of hepatic cancer and provides theoretical evidence support for future clinical practice.

TDO Promotes Hepatocellular Carcinoma Progression

Purpose

Tryptophan 2,3-dioxygenase (TDO), encoded by the gene TDO2, is an enzyme that catalyses the first and rate-limiting step of tryptophan (Try) degradation in the kynurenine (Kyn) pathway in the liver. Recently, TDO has been demonstrated to be expressed in various human tumours, especially hepatocellular carcinoma (HCC). However, the role of TDO in HCC is still not very clear. Here, we studied the role of TDO in HCC.

Methods

We demonstrated that TDO is overexpressed in human HCC tissues and is significantly correlated with malignant phenotype characteristics, including tumour size, tumour differentiation, vascular invasion, etc. Kaplan–Meier analysis showed a poor overall survival rate in patients with TDO-overexpressing tumours. In addition, the effects of TDO on HCC tumour growth and metastasis were detected both in vivo and in vitro. TDO overexpression facilitated HCC cell growth, invasion and migration.

Conclusion

Our results suggest that TDO positively regulates HCC proliferation and invasion and acts as a new prognostic biomarker of HCC.

The androgen receptor as an emerging target in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the male-dominant liver diseases with poor prognosis, although treatments for HCC have been progressing in the past decades. Androgen receptor (AR) is a member of the nuclear receptor superfamily. Previous studies reported that AR was expressed in human HCC and non-HCC tissues. AR is activated both ligand-dependently and ligand-independently. The latter is associated with a mitogen-activated protein kinase–, v-akt murine thymoma viral oncogene homolog 1–, or signal-transducer and activator of transcription–signaling pathway, which has been implicated in the development of HCC. It has been reported that more than 200 RNA expression levels are altered by androgen treatment. In the liver, androgen-responsive genes are cytochrome P450s, transforming growth factor β, vascular endothelial growth factor, and glucose-regulated protein 78 kDa, which are also associated with human hepatocarcinogenesis. Recent studies also revealed that AR plays a role in cell migration and metastasis. It is possible that cross-talk among AR-signaling, endoplasmic reticulum stress, and innate immune response is important for human hepatocarcinogenesis and HCC development. This review shows that AR could play a potential role in human HCC and represent one of the important target molecules for the treatment of HCC.

The Influence of High Serum Testosterone Levels on the Long-term Prognosis in Male Patients Undergoing Hepatectomy for Early Stage Hepatocellular Carcinoma without Vascular Invasion

BACKGROUND

The influence of high serum testosterone levels on the long-term prognosis in male patients undergoing hepatectomy for hepatocellular carcinoma (HCC) remains to be fully elucidated. The aim of the present study was to conduct a retrospective investigation of the impact of high serum testosterone levels on the risk of tumor recurrence and long-term prognosis in male patients undergoing hepatectomy for early stage HCC without vascular invasion.

METHODS

Between August 1995 and March 1999, 42 male patients undergoing curative hepatectomy for HCC of tumor-node-metastasis (TNM) stages I and II without vascular invasion were enrolled in the study. Preoperative serum testosterone concentration was measured. The clinicopathological features, tumor recurrence rates, and 5-year disease-free and actuarial survival after hepatectomy were compared between the patients with serum testosterone levels in the upper half (group I, n = 21) and the patients in the lower half (group II, n = 21).

RESULTS

The background and clinicopathological features did not differ significantly between groups I and group II. All survivors were followed up for more than 5 years. Until March 2005, patients in group I, with serum testosterone levels in the upper half, had a significantly higher percentage of 5-year tumor recurrence than group II, with lower testosterone levels (76.2% versus 28.6%; p < 0.005). The patients in group I also had a significantly inferior 5-year disease-free (p < 0.01) and actuarial (p < 0.05) survival rates than patients in group II.

CONCLUSIONS

Male patients with high serum testosterone levels undergoing hepatectomy for early stage HCC without vascular invasion have significantly higher 5-year tumor recurrence rates and an inferior long-term prognosis than patients with low testosterone levels. These findings signal a strategy of adjuvant anti-androgen treatment selectively targeted for the male patients with high serum testosterone levels after hepatectomy for early stage HCC without vascular invasion to achieve better long-term outcome.

Randomized trial of leuprorelin and flutamide in male patients with hepatocellular carcinoma treated with tamoxifen

The growth of hepatocellular carcinoma (HCC) is thought to be dependent on androgens, as androgen receptors are present in most of these tumors. The aim of this multicenter trial was to assess the effect of antiandrogens in patients who have advanced HCC. Male patients with advanced HCC were randomized into 2 groups treated with (1) leuprorelin (3.75 mg/mo subcutaneously), flutamide (750 mg/d orally), and tamoxifen (30 mg/d orally) or (2) tamoxifen alone (30 mg/d orally) administered until death. Survival was the main end point (log-rank test). The required sample size was 375 patients (alpha, 5%; beta, 10%; 1-year survival, 45% in treated group and 30% in controls). Between February 1994 and January 1998, 376 male patients (mean age, 66 years; treated group, n = 192; control group, n = 184) were included. No baseline imbalance was found between the groups. At the reference date (January 1, 2003), 183 deaths (95.3%) were observed in the treated group and 177 deaths (96.2%) were observed in controls. Thirteen patients were lost to follow-up. Median survival time was estimated to be 135.5 days (95% CI, 112-189) and 176 days (95% CI, 141-227) in treated and control groups, respectively (P = .21). Crude and adjusted relative risks of death in the treated group were estimated at 1.14 (95% CI, 0.93-1.40) and 1.08 (95% CI, 0.87-1.33; P = .48) respectively. Premature interruption of treatment was more frequent in the treated group (n = 45) than in controls (n = 22; P = .0045), mainly because of digestive side effects. In conclusion, no benefit in survival was found with antiandrogenic treatment in male patients with advanced HCC.

Sex hormone dependency of diethylnitrosamine-induced liver tumors in mice and chemoprevention by leuprorelin

The prevalence of liver tumors throughout the world makes it imperative to seek chemopreventive agents. This tumor appears to be hormone-responsive and hormonal manipulations may therefore be beneficial. On this basis, both sexes of 12-day-old B6C3F(1) mice were injected i.p. with diethylnitrosamine (DEN) at the dose of 2.5 mg / g body weight and observed for 32 weeks (males) or 36 weeks (females). In 100% of male mice, liver tumors were observed with an average diameter of 2.72 mm and multiplicity of 60.8. Orchidectomy at 6 weeks of age in these mice inhibited the incidence, multiplicity and size to 63%, 5.6 and 1.54 mm, respectively. By further implantation with an E(2) pellet at monthly intervals, these parameters were reduced to 26%, 0.6 and 0.61 mm, respectively. Administration of a gonadotropin-blocking chemical, leuprorelin, to DEN-treated male mice significantly reduced the multiplicity and size of tumors to 18.3 and 2.54 mm (P < 0.01 compared to those of DEN only). In female mice, the incidence of liver tumor was significantly smaller than that of males. However, ovariectomy and / or testosterone supplement significantly increased the occurrence of liver tumor. An anti-estrogen, toremifene, caused a marked further decrease of liver tumors. Mitotic indices with bromodeoxyuridine in tumor tissues paralleled the occurrence of liver tumors. Serum testosterone levels were significantly reduced by orchidectomy or by leuprorelin administration. These results further confirm that liver tumor is testosterone-responsive and hormonal manipulation by surgical orchidectomy or by chemical orchidectomy i.e. by leuprorelin, could substantially prevent the appearance of liver tumors.

Endocrine treatment of hepatocellular carcinoma. Any evidence of benefit?

In the past 20 years, a number of studies have investigated the relationship between sex hormones and liver cancer. Experimental studies indicate that a dynamic process, with sequential modifications in the pattern of sex hormones in the serum and of sex hormone receptors in the liver, occurs progressively during hepatocarcinogenesis. Overall, it seems that both androgens and oestrogens may enhance liver carcinogenesis, while androgens may also support the growth of established liver tumours. Unfortunately, clinical studies of endocrine treatment of hepatocellular carcinoma (HCC) have not adequately tested the suggestions from biological studies. So far, no clinical trial has been performed to test the efficacy of endocrine manipulation for the chemoprevention of HCC in cirrhotic patients nor in preventing relapse after radical resection of primary HCC. Anti-oestrogens have been the most studied agents for the endocrine treatment of established HCC, although the rationale that supports their use is weaker than for anti-androgens. Studies with anti-androgens have produced prevalently negative results, due to either a lack of activity or excessive toxicity. The use of chemical castration, which theoretically could enhance the activity of antihormonal compounds, yielded no benefit at all. In summary, there is, as yet, no definitive evidence that endocrine treatment favourably affects the outcome of patients with HCC.

Heterogeneity in androgen receptor levels and growth response to dihydrotestosterone in sublines derived from human hepatocellular carcinoma line (KYN-1)

Heterogeneity in the growth response to androgen and androgen receptor (AR) status in an AR-positive human hepatocellular carcinoma (HCC) line, KYN-1, was investigated in the present study. Seven sublines were obtained from KYN-1 by the limited dilution method. Four of them had no detectable amounts of AR and did not show any growth response to dihydrotestosterone (DHT) at the concentration up to 1000 nM, while the other three had varying amounts of both cytosolic and nucleosolic AR that were 5- to 7-fold higher than that of the parent cell. In the parent cell, the addition of DHT caused a modest but significant increase in the cell number (21%) in a 14-day culture. Such effect was increased by 2- to 7-fold in two AR-positive sublines. In addition, the sensitivity of the response in these two sublines was increased by up to 24-fold. The one remaining AR-positive subline did not show any growth response to DHT, although the behavior of its AR in sucrose gradient ultracentrifugation and Western blotting was the same as that of the other two sublines. These data clearly show that sublines derived from an established human HCC line have a broad heterogeneity in the growth response of HCC to androgen as well as in AR status and could be classified into three groups on the basis of the growth responsiveness to androgen and the AR expression.

Cellular distribution of androgen receptors in the liver

In order to determine the cellular distribution of androgen receptors (AR) in normal liver and to examine whether phenotypic changes occur in a variety of non-neoplastic liver diseases, cryostat sections of explanted livers removed from 52 consecutive patients undergoing orthotopic transplantation were immunostained using an anti-androgen receptor monoclonal antibody. In histologically normal liver, AR was immunolocalised to the nuclei of hepatocytes. The proportion of positive hepatocytes varied from about 50% to greater than 90%. Staining, of variable intensity, was restricted to parenchymal cells with no evidence of zonal heterogeneity with respect to labelling intensity. In tissue from patients with biliary cirrhoses and in some cases of alcoholic cirrhosis, labelling for AR was observed in areas of ductular metaplasia but not in areas of "typical" ductular reaction (ductular proliferation). Otherwise, no consistent abnormalities in immunolabelling were seen in any of the diseased livers.

Androgen receptors in hepatocellular carcinoma and surrounding liver: relationship with tumor size and recurrence rate after surgical resection

BACKGROUND/AIMS

This study aimed to evaluate the parameters associated with the presence of androgen receptors in hepatocellular carcinoma and surrounding non-tumoral liver. Furthermore, we have assessed whether androgen receptor positivity influences disease recurrence after surgical resection.

METHODS

Androgen receptor concentration was calculated by receptor binding assay in tumoral and non-tumoral liver in 43 patients (40 of them with cirrhosis) with hepatocellular carcinoma who underwent surgical resection.

RESULTS

Androgen receptors were found in 28 of the tumoral and in 30 of the non-tumoral samples, at concentrations ranging between 5 and 211 fmol/mg protein. The presence of androgen receptors within the tumor was significantly related to a smaller tumor size. Thereby, 22 of the 29 nodules < or = 3 cm contained androgen receptors, while this occurred in only six of the 14 tumors larger than 3 cm (p < 0.05). In contrast, the only parameter associated with the presence of androgen receptors in the non-tumoral liver was a lower gamma-glutamyltranspeptidase concentration. Disease recurrence after surgical resection was not only related to some tumor characteristics (increased alfa-fetoprotein concentration, presence of satellites, differentiation degree), but also to the presence of androgen receptors in the surrounding liver. Thus, the probability of recurrence after 1- and 2-year follow up in patients with androgen-positive livers was 33% and 50%, respectively, while it was 0% and 20% in those with androgen-negative livers (p < 0.05). In contrast, the presence of androgen receptors within the tumor was not associated with a higher recurrence rate.

CONCLUSIONS

These results show that only two thirds of hepatocellular carcinomas contained androgen receptors and that this feature was more frequent in small tumors. In addition, our data indicate that the presence of androgen receptors within the tumor does not imply a different outcome after surgical resection. In contrast, the presence of these receptors in the surrounding non-tumoral liver may be considered a risk factor for a higher incidence of disease recurrence.

Androgen and oestrogen receptors in hepatocellular carcinoma and surrounding liver parenchyma: impact on intrahepatic recurrence after hepatic resection

Seventy-eight patients in whom androgen or oestrogen receptors, or both, were assayed in hepatocellular carcinoma (HCC) and the surrounding liver were discharged from hospital after curative resection of the tumour. Intrahepatic recurrence was evaluated retrospectively after 28-128 months follow-up to determine the association with receptor status. Androgen and oestrogen receptors in HCC significantly influenced the intrahepatic recurrence rate. The recurrence-free 5-year survival rate was 55 per cent for patients who had androgen receptor-negative tumours, 24 per cent for oestrogen receptor-negative, 10 per cent for oestrogen receptor-positive and 0 for androgen receptor-positive (P = 0.0322). Recurrence-free 5-year survival in 57 patients who had both receptor assays was 75 per cent for patients who had androgen receptor-negative, oestrogen receptor-negative tumours, 50 per cent for androgen receptor-negative, oestrogen receptor-positive, but 0 for androgen receptor-positive, oestrogen receptor-positive and androgen receptor-positive, oestrogen receptor-negative (P = 0.0104). The presence or absence of androgen or oestrogen receptor in the liver, however, was not associated with intrahepatic recurrence (P = 0.7534). Thus, androgen receptors are strongly associated with intrahepatic recurrence of HCC, while oestrogen receptors are weakly associated. Receptor status in the normal liver was not related to intrahepatic recurrence.

Effect of androgens and their manipulation on cell growth and androgen receptor (AR) levels in AR-positive and -negative human hepatocellular carcinomas

BACKGROUND/AIMS

Little is known about genuine roles of androgens and their receptor in hepatocellular carcinoma.

METHODS

In the present study, two sublines derived from a human hepatocellular carcinoma cell line KYN-1 were used: KYN-1/SM10 with androgen receptor and KYN-1/SM2 without androgen receptor.

RESULTS

The binding assay with 3H-R1881 identified the presence of both cytosolic and nucleosolic androgen receptors in KYN-1/SM10 but not in KYN-1/SM2. In serum-free medium, dihydrotestosterone was able to enhance the cell proliferation and 3H-thymidine incorporation in androgen receptor positive KYN-1/SM10 cells. Such effects of dihydrotestosterone were partially inhibited by an antiandrogen cyproterone acetate in a concentration-dependent manner. On the other hand, the growth of androgen receptor negative KYN-1/SM2 cells was not influenced by dihydrotestosterone and cyproterone acetate at all. When dihydrotestosterone was removed from the medium of KYN-1/SM10 cultures, the nucleosolic androgen receptor decreased to undetectable levels within 8 h and the cytosolic androgen receptor within 48 h. Addition of dihydrotestosterone (10 nM) to the cells that had been deprived of dihydrotestosterone for 24 h partially restored both cytosolic and nucleosolic androgen receptor within 12 h.

CONCLUSION

The current results seem to indicate that the growth of androgen receptor positive human hepatocellular carcinoma may be enhanced with androgen through androgen receptors and that antiandrogen therapy with cyproterone acetate may be effective in the treatment of androgen receptor-positive hepatocellular carcinoma.

Detection of human androgen receptor mRNA in hepatocellular carcinoma by in situ hybridisation

Recent evidence suggests that anti-androgen therapy may be useful in patients with androgen receptor (AR)-positive hepatocellular carcinomas (HCC), as determined by a steroid binding assay. To evaluate the AR expression of HCC, in both histological and cytological material, we developed a non-radioisotopic in situ hybridisation (NISH) assay specific for the human AR mRNA. A synthetic oligonucleotide complementary to positions 661-695 of the human AR coding sequence was end-labelled with digoxigenin-dUTP and revealed by an alkaline phosphatase-conjugated anti-digoxigenin antibody. We analysed 22 formalin-fixed, paraffin-embedded HCC, obtained at surgery, together with the corresponding non-neoplastic liver tissues (19 cases). In six cases, cell blocks obtained by fine-needle aspiration (FNA) prior to surgery were also available. Positive controls included seminal vesicles and prostate tissues. Sixteen HCCs (73%) expressed a variable amount of AR mRNA, with the proportion of positive cells ranging from very few to more than 90%. Normal hepatocytes were stained weakly and focally in eight cases (42%). Appropriate controls, inclusive of immunohistochemical detection of the AR protein in selected cases, established the specificity of the assay. Data obtained on FNA specimens were predictive of the results on histologic material. However, in two cases the NISH assay was negative on the cytological specimen but stained rare hepatocytes within the surgically resected tumor. In conclusion, NISH is a novel procedure for rapid and specific assessment of the expression of AR in HCC tissue. Its clinical significance, in terms of predictivity of response to anti-androgen treatment, needs to be assessed in large correlative studies.

Sex hormone receptors in hepatocellular carcinoma. Is there a rationale for hormonal treatment?

The present study assessed the tumor concentration of receptors for estrogens, progesterone and androgens in a series of Western patients with hepatocellular carcinoma. Receptors for estrogens and for progesterone were determined by enzyme immunoassay, while androgen receptors were determined by receptor binding assay. Receptors for progesterone were always absent. Estrogen receptors were detected in only 4 tumors, while in the remaining specimens estrogen receptor concentration was lower than 5 fmol/mg of protein. The concentration of receptors within the tumor was not related to the presence of receptor in the non-tumoral liver, which contained estrogen receptors in 12 cases, ranging between 5 and 27 fmol/mg of protein. In contrast, 14 of the 26 tumors contained androgen receptors at concentrations ranging between 2 and 211 fmol/mg of protein; these were not related to the characteristics of the underlying liver, which contained androgen receptors in 14 cases. The results suggest that the beneficial effects of tamoxifen on the survival of patients with hepatocellular carcinoma cannot be explained by the action of this drug on estrogen receptors and that anti-androgen therapy may have some benefit in patients with androgen-receptor-positive tumors.