1 alpha,25-Dihydroxyvitamin D(3) inhibits rat liver ultrastructural changes in diethylnitrosamine-initiated and phenobarbital promoted rat hepatocarcinogenesis

Current therapies in alleviating liver disorders and cancers with a special focus on the potential of vitamin D

Background

Liver dysfunction is a topic of global concern with many advancing therapies being researched. Though vitamin D takes a center place, other therapies especially nutritional are also gaining ground. Vitamin D has gone beyond its role in skeletal disorders by showcasing its associations in other metabolic dysfunctions too.

Result

Epidemiological evidences show a correlation between the status of vitamin D and different forms of cancer. Vitamin D receptors and alterations in gene expression appear decisive in the development of chronic liver disorders. Nutritional status therefore plays a significant role in avoiding the complications related to liver dysfunctions, making it mandatory in maintaining vitamin D sufficiency in the body. Therapies with omega-3 fatty acids, antioxidants, amino acids, steroids also render benefits which could be further explored. Recent research on the progression of certain forms of liver cancer using vitamin D analogs like Seocalcitol EB 1089 has shown good promise.

Conclusion

The anti-inflammatory and immuno- regulatory properties of vitamin D makes its analogs, suitable candidates of better choice for the prevention and treatment of liver disorders and cancer.

Synergistic effect of curcumin and piperine in suppression of DENA-induced hepatocellular carcinoma in rats

Curcumin has been reported to suppress different types of clinical and experimentally-induced tumors, but due to less absorption and quick metabolism it show poor bioavailability. The present study was envisaged to investigate the possible synergistic effect of combined treatment of curcumin with piperine in suppression of diethylnitrosamine (DENA)-induced hepatocellular carcinoma (HCC) in rats, owing to permeability enhancing effect of latter. HCC was induced by supplying DENA (0.01%) in drinking water for 10 weeks. The rats were treated with curcumin (100mg/kg; p.o.) per se and curcumin along with piperine (20mg/kg; p.o.) for 4 weeks post HCC induction. The combined treatment significantly attenuated the morphological, histopathological, biochemical, apoptotic and proliferative changes in the liver and serum in comparison to curcumin per se and vehicle control group. The results of present study concluded that curcumin in combination with piperine shows better suppression of DENA-induced HCC in contrast to curcumin per se.

Targeting the inflammation in HCV-associated hepatocellular carcinoma: a role in the prevention and treatment

Epidemiological, preclinical and clinical studies demonstrated that chronic inflammation induced by hepatitis C virus (HCV) is crucial in hepatocellular carcinogenesis. The interaction between hepatocytes and microenvironment regards virus, inflammatory and immunocompetent cells, chemo- and cyto-kines, reactive oxygen species (ROS) and nitric oxide (NO), generating cell transformation. We suggest hepatocarcinoma (HCC) as a model in which the targeting of microenvironment determine neoplastic transformation. The present review focuses on: the role of inflammation in carcinogenesis, the clinical impact of HCC and the inadequacy of the actual therapy, the chemoprevention targeting the microenvironment.

Impact of chewing betel-nut (Areca catechu) on liver cirrhosis and hepatocellular carcinoma: a population-based study from an area with a high prevalence of hepatitis B and C infections

BACKGROUND

Chewing betel-nuts (Areca catechu) is carcinogenic but the risk for hepatocellular carcinoma (HCC) and liver cirrhosis (LC) is little considered. Worldwide 600 million people chew betel, including emigrants from palm-growing countries.

OBJECTIVE

We aimed to assess the relationships and dose-response effects of betel chewing on LC and HCC risks, since habit cessation could reduce the increased risks of HCC and LC found in such communities.

SUBJECTS

Screening 60 326 subjects aged 30-79 years in a population-based study in Taiwan identified LC in 588 and HCC in 131 subjects. Demographic features, hepatitis B/C infections, other risk factors and betel chewing were noted. Multiple Cox regression models were used to assess independent relationships, interactions and synergisms between age, betel chewing and hepatitis B/C.

RESULTS

Betel chewing increased LC and HCC risk 4.25-fold (95 % CI 2.9, 6.2) in current chewers and 1.89-fold (95 % CI 1.13, 3.16) in ex-chewers v. never-chewers, with dose effects for quantity, duration and cumulative exposure in chewers. Subjects without hepatitis B/C infections had 5.0-fold (95 % CI 2.87, 9.03) increased risk of LC/HCC v. never-chewers, and betel chewing had an additive synergistic effect on hepatitis B/C-related risks. Risk reduction with betel habit cessation could exceed that expected from immunization programmes for hepatitis B and C.

CONCLUSION

Increased risks of cirrhosis and hepatocellular cancer were found in betel chewers free of hepatitis B/C infection, and these risks were synergistically additive to those of hepatitis B/C infections. Estimated risk reduction from effective anti-betel chewing programmes would be sizeable.

Prevention of hepatocarcinogenesis with phosphatidylcholine and menaquinone-4: in vitro and in vivo experiments

BACKGROUND/AIMS

We examined whether phosphatidylcholine inhibited growth of hepatic cancer, as previously shown for menaquinone-4 (vitamin K2).

METHODS

Growth inhibitions by phosphatidylcholine and/or menaquinone-4 and apoptosis induction by phosphatidylcholine were evaluated in vitro using human hepatic cancer cell lines (Hep-3B, Hep-G2, HuH-7, and Alexander). Effects of these agents were then investigated in male Sprague-Dawley rats against hepatocarcinogenesis induced by diethylnitrosamine plus phenobarbital. All rats were killed to examine livers to evaluate inhibitory potential macroscopically and immunohistochemically using an antibody against the marker of carcinogenesis, glutathione S-transferase and apoptotic induction by phosphatidylcholine using TUNEL staining. Blood samples were obtained by cardiac puncture.

RESULTS

In vitro, phosphatidylcholine and menaquinone-4 each inhibited cancer cell growth and phosphatidylcholine induced apoptosis dose-dependently. Moreover, exposure to both synergistically inhibited growth in Hep-3B. In vivo, diets containing phosphatidylcholine with or without menaquinone-4 significantly reduced the number of macroscopic hepatic tumor nodules and the extent of abnormally immunoreactive foci conserving hepatic function on serum examinations compared with controls given only the carcinogens. Moreover, phosphatidylcholine supplementation induced apoptosis on TUNEL staining of liver sections.

CONCLUSIONS

Given together, phosphatidylcholine and menaquinone-4 may exhibit synergy against hepatocarcinogenesis conserving hepatic function that could benefit patients at high risk for hepatocellular carcinoma.

Strategies for cancer prevention: the role of diet

Linkages between diet habits and cancer risk have surfaced from a multitude of epidemiological and preclinical studies. Collectively these studies provide rather compelling evidence that dietary components modify the incidence and biological behavior of tumors. While the risk of breast, prostate, colon, lung and liver cancers are frequently associated with dietary patterns, inconsistencies are not uncommon. These inconsistencies likely reflect the multi-factorial and complex nature of cancer and the specificity that individual dietary constituents have in modifying cancer related genetic pathways. The complexity of defining the role of diet is underscored by the numerous and diverse essential and non-essential components that may alter one or more phases of the cancer process. The explosive increase in the recognition of genes and pathways for regulating cell growth and development, and evaluating the response to hormones and other chemicals synthesized by the body, offers exciting opportunities for unraveling the molecular targets by which dietary components influence cancer prevention. It is recognized that all cells have unique ‘signatures’ that are characterized by active and inactive genes and cellular products. It is certainly plausible that bridging knowledge about these unique cellular characteristics with the molecular targets for nutrients can be used to assist in optimizing nutrition and minimizing cancer risk.

Chemopreventive effects of embelin and curcumin against N-nitrosodiethylamine/phenobarbital-induced hepatocarcinogenesis in Wistar rats

The effects of embelin (50 mg/kg/day), a benzoquinone derivative of Embelia ribes, and the effects of curcumin (100 mg/kg/day), the active principle of Curcuma longa, against N-nitrosodiethylamine (DENA)-initiated and phenobarbital (PB)-promoted hepatocarcinogenesis were studied in Wistar rats. They were able to prevent the induction of hepatic hyper plastic nodules, body weight loss, increase in the levels of hepatic diagnostic markers, and hypoproteinemia induced by DENA/PB treatment. Hence, results of our study suggest the possible chemopreventive effects of embelin (EMB) and curcumin (CUR) against DENA/PB-induced hepatocarcinogenesis in Wistar rats.

Chemoprevention against hepatocellular carcinoma of Cornus officinalis in vitro

The water extracts of Cornus officinalis Sieb. et Zuce against hepatocellular carcinoma (HCC) was studied for its chemopreventive potential. Three HCC cell lines (HepG2, SK-Hep1 and PLC/PRF/5) and three leukemic cell lines (U937, K562 and Raji) were tested with XTT assay. Extracts of C. officinalis inhibited all these HCC cells and leukemic cells at a concentration of 100 microg/ml (P < 0.05) and was dose-dependent (P < 0.0001). P53 (P< 0.0001) and Ras (P = 0.001) significantly affected its activity against HCC. Extracts of C. officinalis also possessed the anti-oxidant activity through free radicals scavenging activity at a concentration of 50 microg/ml (P < 0.05). In summary, our experiment implied that C. officinalis might be a candidate for chemopreventive agent against HCC through the antioxidant and anti-neoplastic effects.

Suppression of diethylnitrosamine and 2-acetylaminofluorene-induced hepatocarcinogenesis in rats by tocotrienol-rich fraction isolated from rice bran oil

The anticancer efficacy of tocotrienol-rich fraction (TRF) was evaluated during diethylnitrosamine (DEN)/2-acetylaminofluorene (AAF)-induced hepatocarcinogenesis in male Sprague-Dawley rats. TRF treatment was carried out for 6 months, and was started 2 weeks before initiation phase of hepatocarcinogenesis. Morphological examination of the livers from DEN/AAF rats showed numerous off-white patches and few small nodules, which were significantly reduced by TRF treatment. Cytotoxic damage by DEN/AAF was estimated by alkaline phosphatase (ALP) release into the plasma from the cell membranes. DEN/AAF caused a twofold increase in the activity of ALP in plasma as compared with normal control rats, and this increase was prevented significantly by TRF treatment. We observed an increase of 79% in liver ALP activity in DEN/AAF rats, which was further increased by another 48% after the administration of TRF. Hepatic activity of glutathione S-transferase (GST) was also increased (3.5-fold) during the induction of hepatic carcinogenesis. Lipid peroxidation and low-density lipoprotein (LDL) oxidation increased threefold following initiation by DEN/AAF as compared with normal control rats. However, TRF treatment to DEN/AAF-treated rats substantially decreased (62-66%) the above parameters and thus limited the action of DEN/AAF. We conclude that long-term intake of TRF could reduce cancer risk by preventing hepatic lipid peroxidation and protein oxidation damage due to its antioxidant actions.

Antiproliferative role of vitamin D and its analogs--a brief overview

The active metabolite of vitamin D, 1alpha, 25-dihydroxyvitamin D3 [1,25(OH)2D3]--a seco-steroid hormone is a pivotal regulator of cellular proliferation and differentiation those are independent of its classical function of calcium homeostasis and bone mineralization. The existence of the nuclear vitamin D receptor (VDR) has been found in numerous tissues in different organs, which are the so-called 'non-classical' targets of this seco-steroid hormone. Vitamin D has been documented as a potent antiproliferative agent in different tissues and cells. Epidemiological studies reveal a negative correlation between physiological level of vitamin and cancer risk. Studies using animal models clearly demonstrate protective role of vitamin D in different cancer types by the reduction in tumor progression and by monitoring biochemical parameters. Experiments with cultured human and animal cancer cell lines show similar antiproliferative role of vitamin D manifested by up or down regulations of crucial genes leading to inhibition of cellular growth. Hypercalcemia hinders broad-spectrum therapeutic uses of vitamin D in cancer chemotherapy. Application of vitamin D analogs having similar chemical structures or other compounds having vitamin D like actions but lacking calcemic adverse effects are getting significant attention towards rational therapeutics to treat cancer. The current review focuses on the application of vitamin D and its analogs in different forms of cancer and on the molecular mechanism involved in vitamin D mediated inhibition in cellular proliferation, cell cycle, induction of apoptosis and tumor suppression, which may eventually evolve as a meaningful cancer therapy.

Prevention of liver cancer

Hepatocellular carcinoma (HCC) is among the most prevalent and deadly cancers worldwide. Prominent risk factors for HCC include viral hepatitis infection; dietary exposure to hepatotoxic contaminants such as aflatoxins; alcoholism; smoking; and male gender. This review highlights ongoing efforts in HCC prevention. Strategies include vaccination against, and treatment of, viral hepatitis infection. In addition to interferon alpha, an acyclic retinoid (all-trans-3,7,11, 15-tetramethyl-2,4,6,10,14-hexadecapentanoic acid), glycyrrhizin and ginseng are currently under clinical investigation for HCC prevention in Japanese hepatitis C patients. Several recent clinical studies in a Chinese region of pervasive aflatoxin contamination also support the approach of favorably altering aflatoxin metabolism and excretion using the chemopreventive agents oltipraz or chlorophyllin. Agents exhibiting chemopreventive efficacy in preclinical HCC models include vitamins A, D, and E, herbal extracts, a 5alpha-reductase inhibitor, green tea, and D-limonene. Efforts to elucidate the molecular lesions and processes underlying HCC development have identified several putative molecular targets for preventive interventions. These include genes and gene products controlling viral replication, carcinogen metabolism, signal transduction, cell-cycle arrest, apoptosis, proliferation, and oxidative stress.

1alpha,25-Dihydroxyvitamin D(3) inhibits rat liver ultrastructural changes and the development of gamma-glutamyltranspeptidase-positive foci in diethylnitrosamine-initiated and streptozotocin-induced diabetes-promoted hepatocarcinogenesis

In the present study, the chemopreventive effect of the active metabolite of vitamin D, 1alpha,25-dihydroxyvitamin D(3) (VD(3)), against chemically-induced and diabetes-promoted rat liver carcinogenesis was investigated. Hepatocarcinogenesis was initiated with a single intraperitoneal (i.p.) injection of diethylnitrosamine (DEN) (125 mg kg(-1) body weight) at week 4 followed by promotion with streptozotocin (STZ) (65 mg kg(-1) body weight with a single i.p. injection) at week 7. With this basic experimental regimen, the effect of VD(3) (0.3 microg (0.1 ml)(-1) propylene glycol per os twice a week) was investigated with effect from 4 weeks prior to the exposure of DEN. The results showed that VD(3) supplementation throughout the experimental period reduced the incidence, total number and multiplicity and altered the size of visible persistent nodules (PNs) in DEN- or DEN + STZ-treated rats as compared with their respective controls. In these two groups, it also caused a significant decrease in the number (p < 0.002 and 0.001 respectively) and focal area (p < 0.05) of gamma-glutamyltranspeptidase (GGT)-positive hepatic foci. Moreover, continuous supplementation of VD(3) exhibits a protective effect in maintaining the normal cellular architecture of the hepatocytes in DEN- or DEN + STZ-treated rats. Our results thus strongly suggest that VD(3) is very effective in the inhibition of DEN-initiated and STZ-induced diabetes-promoted rat liver carcinogenesis.