Tamoxifen induced-non-alcoholic steatohepatitis (NASH): has the time come for the oncologist to be diabetologist

Identification of protein partners for small molecules reshapes the understanding of nonalcoholic steatohepatitis and drug discovery

AIMS

Nonalcoholic steatohepatitis (NASH) is the severe subtype of nonalcoholic fatty diseases (NAFLD) with few options for treatment. Patients with NASH exhibit partial responses to the current therapeutics and adverse effects. Identification of the binding proteins for the drugs is essential to understanding the mechanism and adverse effects of the drugs and fuels the discovery of potent and safe drugs. This paper aims to critically discuss recent advances in covalent and noncovalent approaches for identifying binding proteins that mediate NASH progression, along with an in-depth analysis of the mechanisms by which these targets regulate NASH.

MATERIALS AND METHODS

A literature search was conducted to identify the relevant studies in the database of PubMed and the American Chemical Society. The search covered articles published from January 1990 to July 2024, using the search terms with keywords such as NASH, benzophenone, diazirine, photo-affinity labeling, thermal protein profiling, CETSA, target identification.

KEY FINDINGS

The covalent approaches utilize drugs modified with diazirine and benzophenone to covalently crosslink with the target proteins, which facilitates the purification and identification of target proteins. In addition, they map the binding sites in the target proteins. By contrast, noncovalent approaches identify the binding targets of unmodified drugs in the intact cell proteome. The advantages and limitations of both approaches have been compared, along with a comprehensive analysis of recent innovations that further enhance the efficiency and specificity.

SIGNIFICANCE

The analyses of the applicability of these approaches provide novel tools to delineate NASH pathogenesis and promote drug discovery.

Investigating the tamoxifen/high-fat diet synergy: a promising paradigm for nonalcoholic steatohepatitis induction in a rat model

Non-alcoholic steatohepatitis (NASH) is a severe liver condition characterized by excessive fat deposition, ballooning, and lobular inflammation. This investigation was conducted to estimate the capability of concomitant tamoxifen administration (TAM) with a high fat diet (HFD) to induce a reliable NASH model that mimics human NASH features. Rats were administered TAM (25 mg/kg/day p.o.) and consumed HFD for 5 weeks. A time-course investigation was conducted to determine the optimal time for NASH development. Liver function indices, hepatic lipid profile factors, oxidative stress biomarkers, and inflammatory mediators were estimated. Additionally, macroscopic and microscopic changes were examined. Compared with the time-matched control group receiving vehicle alone, TAM/HFD significantly impaired liver function indices represented as marked elevation in ALT, AST, and ALP serum levels. TAM/HFD significantly increased lipid profile factors including high TG and TC hepatic levels. Additionally, TAM/HFD remarkably raised hepatic levels of TNF-α and IL-17 and significantly decreased IL-10. The combination also increases the oxidative status evidenced by high content of MDA as well as low activity of GPx and SOD. Accordingly, the combination of TAM and HFD for 5 weeks collaboratively promotes NASH development by initiating compromised hepatocyte functionality, elevated lipid levels, oxidative stress, and liver inflammation.

Fatty Liver in Hormone Receptor-Positive Breast Cancer and Its Impact on Patient's Survival

Purpose

Long-term estrogen inhibition may cause fatty liver disease (non-alcoholic fatty liver disease; NAFLD) among other adverse conditions such as osteoporosis, climacteric symptoms, thromboembolism, dyslipidemia, and metabolic syndrome. The prevalence of NAFLD among breast cancer patients ranges from 2.3%–45.2%. This study aimed to determine the risk factors for newly developed NAFLD among breast cancer patients after hormonal treatment and whether it influences survival outcomes.

Methods

This retrospective study investigated hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative (HR+/HER2−), nonmetastatic breast cancer patients diagnosed between January 2010 and December 2018. All patients received adjuvant hormonal treatment for at least 6 months. Clinical data on metabolic profile indicators such as body mass index (BMI), waist circumference, serum cholesterol, triglycerides, low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C), diabetes, and presence of metabolic syndrome (MetS) were collected. In total, 160 eligible patients with complete covariate data and survival follow-up were included.

Results

NAFLD was diagnosed in 35% of patients. There were significant associations of being overweight (BMI ≥ 25 kg/m²), waist circumference > 80 cm, triglycerides ≥ 150 mg/dL, HDL-C ≤ 50 mg/dL, LDL-C < 150 mg/dL, and presence of MetS with the development of NAFLD. However, unlike other factors, MetS and HDL-C were not independently associated with NAFLD. Patients with breast cancer who developed NAFLD had longer disease-free survival (DFS). The median DFS was not reached in the NAFLD group, whereas it was 59.3 (45.6–73.0) months in the non-NAFLD group. No worsening of overall survival was observed in patients with breast cancer and NAFLD.

Conclusion

The development of NAFLD during treatment in patients with HR+/HER2− breast cancer was associated with several independent risk factors: being overweight, waist circumference, triglycerides, and LDL-C. Interestingly, breast cancer patients with NAFLD during treatment had longer DFS than those without NAFLD.

Drug-induced hepatotoxicity in cancer patients - implication for treatment

INTRODUCTION

All anticancer drugs can cause idiosyncratic liver injury. Therefore, hepatoprotective agents assume particular importance to preserve liver function. Hepatic injury represents 10% of cases of acute hepatitis in adults; drug-related damage is still misjudged because of relative clinical underestimation and difficult differential diagnosis. Chemotherapeutic agents can produce liver toxicity through different pathways, resulting in different categories of liver injuries, but these drugs are not homogeneously hepatotoxic. Frequently, anticancer-induced hepatotoxicity is idiosyncratic and influenced by multiple factors.

AREAS COVERED

The aim of this paper is to perform a review of the literature regarding anticancer-induced liver toxicity. We described hepatotoxicity mechanisms of principal anticancer agents and respective dose reductions. Furthermore, we reviewed studies on hepatoprotectors and their optimal use. Tiopronin, magnesium isoglycyrrhizinate and S-Adenosylmethionine (AdoMet) demonstrated, in some small studies, a potential hepatoprotective activity.

EXPERT OPINION

Actually, in the literature only small experiences are reported. Even though hepatoprotective agents seem to be useful in the oncologic setting, the lack of well-designed prospective Phase III randomized controlled trials is a major limit in the introduction of hepatoprotectors in cancer patients and these kind of studies are warranted to support their use and to give further recommendations for the clinical practice.

Liver injury induced by anticancer chemotherapy and radiation therapy

Cytotoxic chemotherapy prolongs survival of patients with advanced and metastatic tumors. This is, however, a double-edged sword with many adverse effects. Since the liver has a rich blood supply and plays an active role in the metabolism of medications, it is not surprising that there can be hepatic injury related to chemotherapy. In addition, radioembolization may affect the parenchyma of normal and cirrhotic livers. We review chemotherapy-associated liver injury in patients with colorectal liver metastases, including downsizing chemotherapy and neoadjuvant chemotherapy. We discuss the mechanism of the hepatic injury, secondary to reactive oxygen species, and the spectrum of hepatic injury including, steatosis, steatohepatitis, hepatic sinusoidal injury and highlight the pharmacogenomics of such liver insults. Methods for reducing and treating the hepatotoxicity are discussed for specific agents including tamxifen and the newly introduced targeted antibodies.

Treatment of nonalcoholic fatty liver disease in adults and children: a closer look at the arsenal

Nonalcoholic fatty liver disease encompasses a spectrum of disease from asymptomatic steatosis, with or without elevated aminotransferases, to cirrhosis with relative complications and hepatocellular carcinoma. Owing to the increasing prevalence of nonalcoholic fatty liver disease and the potential for nonalcoholic steatohepatitis to progress to cirrhosis and liver-related mortality, more research has been focused on therapy of this important liver disease over the last two decades. To date, weight loss and physical activity represent the cornerstone of treatment, with interventions being limited to subjects at risk of disease progression, but the type of treatment remains a matter of debate. A few medications have shown promising results in preliminary pilot studies, but few agents have been tested rigorously. Today, multiple therapeutic approaches are considered the way to go in treating nonalcoholic steatohepatitis patients. In this paper we review the status of current and emerging therapeutic strategies for children and adult patients with nonalcoholic steatohepatitis.

Incidence and risk factors for non-alcoholic steatohepatitis in females treated with tamoxifen for breast cancer

BACKGROUND AND STUDY AIMS

Tamoxifen used in the treatment of breast cancer is reported to cause hepatic steatosis. This study aimed to assess the incidence and risk factors of the development of fatty liver disease, resulting from tamoxifen use, in females with breast cancer.

PATIENTS AND METHODS

Seventy females aged between 28 and 80years with breast cancer were recruited from Shahid Sadoughi Clinic, Yazd, Iran in 2006-2008. The patients underwent chemotherapy followed by 20mg tamoxifen daily as postoperative endocrine treatment. Only in patients with normal baseline liver function, negative test for hepatitis C virus (HCV) and hepatitis B surface antigen (HbsAg) and normal liver ultrasonography were included. The development of fatty changes over a 6-months period of treatment was the main outcome measurement assessed by ultrasonography.

RESULTS

Thirty-five of 70 patients developed fatty change during follow-up, in which nine were in grade one, 20 in grade two and six patients in grade three. Risk factors associated with the development of fatty change were elevation of triglycerides (2.4, 1.2-4.8), elevation of fasting blood sugar (FBS) and low high-density lipoprotein (HDL) (3.4, 1.4-7.8). No relation was found between the development of fatty change and age (1.3, 0.87-2.00), menopause (1.13, 0.69-1.9), previous history of diabetes (2.4, 0.7-8.4), previous chemotherapy regimen and receptors type (c-erbB2, P53, progesterone receptor (PR), oestrogen receptor (ER)) and stage of breast cancer. Further, there was no relation between the development of fatty change and hypercholesterolemia, low-density lipoprotein (LDL), arterial hypertension and body mass index (BMI).

CONCLUSION

Tamoxifen was associated with a high risk of development of non-alcoholic steatohepatitis in patients with higher triglycerides and FBS and lower HDL. However, no relationship was found with the level of BMI, LDL, hypertension, overweight and obesity.

Gene expression profiling of murine hepatic steatosis induced by tamoxifen

Tamoxifen is an antiestrogenic agent used widely in the treatment of estrogen receptor-positive breast cancer. However, hepatic steatosis has been reported during clinical trials of tamoxifen. To explore the mechanism responsible for this tamoxifen-induced hepatic steatosis, we used microarray analysis to profile the gene expression pattern of mouse liver after tamoxifen treatment. Tamoxifen was administered orally as a single dose of 10mg/kg (low dose), 50mg/kg (medium dose), or 100mg/kg (high dose) to C57BL/6 mice, and the livers were removed 2h, 4h, 8h, and 24h later. From microarray data obtained from the liver samples, 414 genes were selected as tamoxifen-responsive genes (P<0.05, two-way ANOVA; cutoff ≥ 1.5-fold response). These genes were classified into three groups: 308 of the 414 genes showed a time-dependent response, nine genes showed a dose-dependent response, and 97 genes showed a time- and dose-dependent response. Most of the 308 time-dependent-responsive genes were associated predominantly with the biological processes involved in lipid metabolism. Overrepresented transcription factor binding site analysis showed that the following nuclear receptors that are important in lipid and carbohydrate metabolism were overrepresented: the androgen receptor (AR), nuclear receptor subfamily 2 group F member 1 (NR2F1), hepatocyte nuclear factor 4α (HNF4α), and retinoic acid receptor-related orphan receptor alpha 1 (RORα1). Reporter gene analysis further revealed that tamoxifen repressed the 5α-dihydrotestosterone-induced activation of the AR and the intrinsic transactivation function of RORα1, HNF4α, and NR2F1. Taken together, these data provide a better understanding of the molecular mechanism underlying tamoxifen-induced steatogenic hepatotoxicity and useful information for predicting steatogenic hepatotoxicity.

Nicotinamide overload may play a role in the development of type 2 diabetes

AIM: To investigate whether nicotinamide overload plays a role in type 2 diabetes.

METHODS: Nicotinamide metabolic patterns of 14 diabetic and 14 non-diabetic subjects were compared using HPLC. Cumulative effects of nicotinamide and N¹-methylnicotinamide on glucose metabolism, plasma H₂O₂ levels and tissue nicotinamide adenine dinucleotide (NAD) contents of adult Sprague-Dawley rats were observed. The role of human sweat glands and rat skin in nicotinamide metabolism was investigated using sauna and burn injury, respectively.

RESULTS: Diabetic subjects had significantly higher plasma N¹-methylnicotinamide levels 5 h after a 100-mg nicotinamide load than the non-diabetic subjects (0.89 ± 0.13 μmol/L vs 0.6 ± 0.13 μmol/L, P < 0.001). Cumulative doses of nicotinamide (2 g/kg) significantly increased rat plasma N¹-methylnicotinamide concentrations associated with severe insulin resistance, which was mimicked by N¹-methylnicotinamide. Moreover, cumulative exposure to N¹-methylnicotinamide (2 g/kg) markedly reduced rat muscle and liver NAD contents and erythrocyte NAD/NADH ratio, and increased plasma H₂O₂ levels. Decrease in NAD/NADH ratio and increase in H₂O₂ generation were also observed in human erythrocytes after exposure to N¹-methylnicotinamide in vitro. Sweating eliminated excessive nicotinamide (5.3-fold increase in sweat nicotinamide concentration 1 h after a 100-mg nicotinamide load). Skin damage or aldehyde oxidase inhibition with tamoxifen or olanzapine, both being notorious for impairing glucose tolerance, delayed N¹-methylnicotinamide clearance.

CONCLUSION: These findings suggest that nicotinamide overload, which induced an increase in plasma N¹-methylnicotinamide, associated with oxidative stress and insulin resistance, plays a role in type 2 diabetes.

The association of nonalcoholic steatohepatitis and tamoxifen in patients with breast cancer

BACKGROUND

Nonalcoholic steatohepatitis (NASH) is a form of liver damage that can progress to cirrhosis. NASH is associated with obesity and diabetes. The condition also may be associated with some medications, including tamoxifen. Early case reports and small series have documented NASH in patients who received tamoxifen.

METHODS

The records of patients registered in the St. Vincent Hospital Cancer Registry of Green Bay Wisconsin from January 1, 1992 to December 31, 2000 were reviewed.

RESULTS

In total, 1105 patients with breast cancer were evaluated for NASH, and 24 cases of NASH were documented (2.2%). Seven patients had NASH before their diagnosis of breast cancer, and 17 patients developed NASH after their diagnosis of breast cancer. In multivariate analysis, the factors associated with NASH were tamoxifen use (odds ratio [OR], 8.2; 95% confidence interval [CI], 1.06-63.72), body mass index (BMI) (OR, 1.13; 95% CI, 1.06-1.20), and age (OR, 95% CI, 0.91-0.99). NASH improved after tamoxifen was stopped. After discontinuation of tamoxifen, transaminase levels returned to normal in 14 of 16 patients.

CONCLUSIONS

NASH was present in 24 of 1105 patients with breast cancer (2.2%). Seven patients had NASH before they were diagnosed with breast cancer, and 17 patients developed NASH after their diagnosis. NASH was associated with the use of tamoxifen and improved when tamoxifen was stopped.

A case-control study of non-alcoholic fatty liver disease in breast cancer

BACKGROUND

Patients with breast cancer sometimes present with increased liver enzymes during follow-up period that may be consistent with hepatic steatosis. This effect known as non-alcoholic fatty liver disease may be associated with the malignancy itself, drugs or some other well-known risk factors that may induce steatosis. We studied the influences of primary disease and treatment on steatosis in patients with breast cancer.

MATERIALS AND METHODS

There were four groups of patients in our study. Group 1: 40 newly diagnosed, previously untreated breast cancer; Group 2: 45 cases of breast cancer treated with systemic therapy; Group 3: 40 cases of ovarian cancer; Group 4: 40 healthy women. Hepatic steatosis was evaluated by sonography by two radiologist, independently. We also evaluated major risk factors, biochemical findings, and influences of treatment on hepatic steatosis.

RESULTS

We detected steatosis in 63%, 72%, 77%, and 48% of patients in groups 1, 2, 3, and 4, respectively. There was a statistically significant difference only between groups 3 and 4 (P = 0.045). However, grade 2 and 3 steatosis were more frequent in breast cancer patients (group 1 and 2), compared with mild steatosis in ovarian cancer patients and healthy women. Although a good correlation was found between tamoxifen use and chemotherapy on development of non-alcoholic fatty liver disease, no association of hepatic steatosis with transaminase levels was found, which might be of help for earlier detection of steatosis. AST/ALT ratio was found to have no impact on the rate of hepatic steatosis, contrary to the literature.

CONCLUSION

Hepatic steatosis, excluding patients with grade 1 steatosis, which may be a normal variant, were more readily detected in patients with breast cancer. This effect was aggravated by use of tamoxifen, but not the chemotherapy. Non-alcoholic fatty liver disease in patients with breast cancer may be associated with the primary tumor itself or some well-known risk factors such as obesity, hyperlipidemia, and diabetes mellitus, which needs to be explored.

Tamoxifen-induced non-alcoholic steatohepatitis: where are we now and where are we going?

Tamoxifen is a cheap and effective estrogen-receptor antagonist, used as the adjuvant hormonal treatment of choice in women with estrogen-receptor-positive breast cancer. Tamoxifen-induced non-alcoholic steatohepatitis (NASH) may increase the demand on oncologists, not only with regard to screening for diabetes, but also for the suggested link of NASH with high incidence of coronary heart disease. At present, there is no guideline for treatment of hyperlipidaemia associated with tamoxifen-induced NASH. However, exemstane (and other aromatase inhibitors) has been shown to lower triglyceride and have a neutral effect on low-denisty lipoprotein and cholesterol levels. These may be alternative agents if severe progressive liver disease or hyperlipidaemia were encountered with tamoxifen administration. Other lipid-lowering medications may have potential benefits in the treatment of tamoxifen-induced NASH and is discussed in this article.

Statins and breast cancer: a smoking gun or guilt by association?

Statins are widely prescribed, effective cholesterol-lowering drugs. Indeed, atorvastatin and simvastatin were the most commonly prescribed drugs in the US in 2004, with > 70 million prescriptions written for atorvastatin alone. Statins are pleiotropic agents and, after an early study of patients with coronary heart disease showed a lower than expected incidence of cancers, preclinical studies were carried out that have supported the potential anticancer activity of these compounds. However, clinical reports on the relationship between statin use and breast cancer risk have yielded mixed results, with no association and both positive and negative associations being observed. Because breast cancer is the most frequent cancer in women, any link between statin use and breast cancer risk would have major public health implications. The current evidence suggests that statins are safe and effective agents in treating hyperlipidaemia and no evidence of increase or decrease risk of breast cancer. Indeed, more research is needed to define whether long-term statin therapy may decrease or increase the risk of breast cancer.