[Toxic hepatitis associated with tamoxifen use. A case report and literature review]

Pioglitazone attenuates tamoxifen-induced liver damage in rats via modulating Keap1/Nrf2/HO-1 and SIRT1/Notch1 signaling pathways: In-vivo investigations, and molecular docking analysis

BACKGROUND

Tamoxifen (TAM) is a chemotherapeutic drug widely utilized to treat breast cancer. On the other hand, it exerts deleterious cellular effects in clinical applications as an antineoplastic agent, such as liver damage and cirrhosis. TAM-induced hepatic toxicity is mainly attributed to oxidative stress and inflammation. Pioglitazone (PIO), a peroxisome proliferator-activated receptor-gamma (PPAR-γ) agonist, is utilized to treat diabetes mellitus type-2. PIO has been reported to exert anti-inflammatory and antioxidant effects in different tissues. This research assessed the impact of PIO against TAM-induced hepatic intoxication.

METHODS

Rats received PIO (10 mg/kg) and TAM (45 mg/kg) orally for 10 days.

RESULTS

TAM increased aspartate aminotransferase (AST) and alanine aminotransferase (ALT), triggered several histopathological alterations, NF-κB p65, increased hepatic oxidative stress, and pro-inflammatory cytokines. PIO protects against TAM-induced liver dysfunction, reduced malondialdehyde (MDA), and pro-inflammatory markers along with improved hepatic antioxidants. Moreover, PIO, increased hepatic Bcl-2 expression while reducing Bax expression and caspase-3 levels. In addition, PIO decreased Keap-1, Notch1, and Hes-1 while upregulated HO-1, Nrf2, and SIRT1. Molecular docking showed the binding affinity of PIO for Keap-1, NF-κB, and SIRT1.

CONCLUSION

PIO mitigated TAM hepatotoxicity by decreasing apoptosis, inflammation, and oxidative stress. The protecting ability of PIO was accompanied by reducing Keap-1 and NF-κB and regulating Keap1/Nrf2/HO-1 and Sirt1/Notch1 signaling. A schematic diagram illustrating the protective effect of PIO against TAM hepatotoxicity. PIO prevented TAM-induced liver injury by regulating Nrf2/HO-1 and SIRT1/Notch1 signaling and mitigating oxidative stress, inflammation, and apoptosis.

Cyanocobalamin and/or calcitriol mitigate renal damage-mediated by tamoxifen in rats: Implication of caspase-3/NF-κB signaling pathways

AIM

Tamoxifen (TAMO) is a chemotherapeutic drug used for the treatment of breast cancer. Nevertheless, there is a lack of information available in regarding its nephrotoxicity. The purpose of this work was to investigate the impact of cyanocobalamin (COB) and/or calcitriol (CAL) injections on TAMO-induced nephrotoxicity.

MAIN METHODS

Animals were allocated into five groups as follows: normal control group; TAMO (45 mg/kg) administered group; TAMO+COB (6mg/kg, i.p) treated group; TAMO+CAL (0.3 μg/kg, i.p) treated group; TAMO+COB+CAL combination groups.

KEY FINDINGS

Renal injury induced by TAMO was confirmed by the alteration in renal function parameters in the serum (urea and creatinine), as well as in the urine (creatinine clearance, total protein and albumin). These results were supported by histopathological examination. Upregulation of renal inflammatory parameters; tumor necrosis factor (TNF)-α, interleukin (IL)-6, C-reactive protein (CRP); and transforming growth factor (TGF)-β1 as well as in protein expression of nuclear factor-kappa B (NF-κB) and cleaved caspase-3 were observed to a greater extent in the TAMO-treated rats compared with the control. Renal fibrosis was also evidenced by a elevation in renal L-hydroxyproline level as well as by histomorphological collagen deposition in TAMO-treated groups compared to the control group. Administration of COB and/or CAL concurrently with TAMO significantly ameliorated the deviation in the above-studied parameters and improved the histopathological renal picture.

SIGNIFICANCE

Inhibition of NF-κβ-mediated inflammation and caspase-3-induced apoptosis are possible renoprotective mechanisms of COB and/or CAL against TAMO nephrotoxicity, which was more noticeable in the TAMO group treated with the combination of the two vitamins in question.

Thymoquinone: A Tie-Breaker in SARS-CoV2-Infected Cancer Patients?

Since the beginning of the SARS-CoV-2(severe acute respiratory syndrome-coronavirus-2) pandemic, arace to develop a vaccine has been initiated, considering the massive and rather significant economic and healthcare hits that this virus has caused. The pathophysiology occurring following COVID-19(coronavirus disease-2019) infection has givenhints regarding the supportive and symptomatic treatments to establish for patients, as no specific anti-SARS-CoV-2 is available yet. Patient symptoms vary greatly and range from mild symptoms to severe fatal complications. Supportive treatments include antipyretics, antiviral therapies, different combinations of broad-spectrum antibiotics, hydroxychloroquine and plasma transfusion. Unfortunately, cancer patients are at higher risk of viral infection and more likely to develop serious complications due to their immunocompromised state, the fact that they are already administering multiple medications, as well as combined comorbidity compared to the general population. It may seem impossible to find a drug that possesses both potent antiviral and anticancer effects specifically against COVID-19 infection and its complications and the existing malignancy, respectively. Thymoquinone (TQ) is the most pharmacologically active ingredient in Nigella sativa seeds (black seeds); it is reported to have anticancer, anti-inflammatory and antioxidant effects in various settings. In this review, we will discuss the multiple effects of TQ specifically against COVID-19, its beneficial effects against COVID-19 pathophysiology and multiple-organ complications, its use as an adjuvant for supportive COVID-19 therapy and cancer therapy, and finally, its anticancer effects.

Tamoxifen and Sulphoraphane for the breast cancer management: A synergistic nanomedicine approach

Breast cancer is second most leading cause of death in all over the world and not only limited to the females. Tamoxifen has been considered as the gold line therapy for estrogen receptor positive breast cancer. However, this chemopreventive approach has been focused at individuals in high risk group and limits its clinical applications to moderate and/or lower risk groups. Moreover, Tamoxifen treatment is associated with a dose related hepatotoxicity and nephrotoxicity and eventually results in poor quality of life of patients. Sulphoraphane, a naturally occurring isothiocyanate derivative has been investigated for its numerous potential biological activities including anticancer effects. The present hypothesis aims to put forward in which Tamoxifen is combined with a natural bioactive Sulphoraphane, both incorporated into a novel lipid based nanocarrier at a reduced dose, which would eventually shuttle the cargo to the target site. At the breast cancer, Sulphoraphane sensitizes the estrogen receptors and ameliorates the binding affinity of Tamoxifen to these receptors, thereby potentiating the anticancer efficacy and reducing the offsite toxicity of Tamoxifen. This dual loaded zero-dimension lipid carrier would be a value addition to the current treatment regimen for breast cancer management.

Oxidative Stress Plays an Important Role in the Pathogenesis of Drug-Induced Retinopathy

Several pharmaceutical agents have been associated with rare but serious retinopathies, some resulting in blindness. Little is known of the mechanism(s) that produce these injuries. Mechanisms proposed thus far have not been embraced by the medical and scientific communities. However, preclinical and clinical data indicate that oxidative stress may contribute substantially to iatrogenic retinal disease. Retinal oxidative stress may be precipitated by the interaction of putative retinal toxins with the ocular redox system. The retina, replete with cytochromes P450 and myeloperoxidase, may serve to activate xenobiotics to oxidants, resulting in ocular injury. These activated agents may directly form retinal adducts or may diminish ocular reduced glutathione concentrations. Data are reviewed that suggest that indomethacin, tamoxifen, thioridazine, and chloroquine all produce retinopathies via a common mechanism—they produce ocular oxidative stress.

In vitro evaluation of hepatotoxic drugs in human hepatocytes from multiple donors: Identification of P450 activity as a potential risk factor for drug-induced liver injuries

A possible risk factor for drug-induced hepatotoxicity is drug metabolizing enzyme activity, which is known to vary among individuals due to genetic (genetic polymorphism) and environmental factors (environmental pollutants, foods, and medications that are inhibitors or inducers of drug metabolizing enzymes). We hypothesize that hepatic cytochrome P450-dependent monooxygenase (CYP) activity is one of the key risk factors for drug induced liver injuries (DILI) in the human population, especially for drugs that are metabolically activated to cytotoxic/reactive metabolites. Human hepatocytes from 19 donors were evaluated for the activities of 8 major P450 isoforms: CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4. Extensive individual variations were observed, consistent with what is known to be in the human population. As CYP3A4 is known to be one of the most important P450 isoforms for drug metabolism, studies were performed to evaluate the relationship between the in vitro cytotoxicity of hepatotoxic drugs and CYP3A4 activity. In a proof of concept study, hepatocytes from six donors (lots) representing the observed range of CYP3A4 activities were chosen for the evaluation of in vitro hepatotoxicity of four drugs known to be associated with acute liver failure: acetaminophen, cyclophosphamide, ketoconazole, and tamoxifen. The hepatocytes were cultured in collagen-coated plates and treated with the hepatotoxicants for approximately 24 h, followed by viability determination based on cellular adenosine triphosphate (ATP) contents. HH1023, the lot of hepatocytes with the highest CYP3A4 activity, was found to be the most sensitive to the cytotoxicity of all 4 hepatotoxic drugs, thereby suggesting that high CYP3A4 activity may be a risk factor. To further validate the relationship, a second study was performed with hepatocytes from 16 donors. In this study, the hepatocytes were quantified for CYP3A4 activity at the time of treatment. Results of the second study show confirm the correlation between with high CYP3A4 activity and sensitivity to hepatotoxic drugs. Our results with primary cultured hepatocytes from multiple donors support the hypothesis that elevated P450 activity may be a risk factor for drug-induced liver injuries.

Evaluation of endometrial thickness and bone mineral density based on CYP2D6 polymorphisms in Turkish breast cancer patients receiving tamoxifen treatment

BACKGROUND

Several previous studies have examined the effect of CYP2D6 gene polymorphism on the efficacy and metabolism of tamoxifen (Tamoxifen Teva, Nolvadex) in the treatment of breast cancer. In the present study, the metabolic profiles associated with various CYP2D6 genotypes were evaluated.

METHOD

In the present study 92 Turkish breast cancer patients with early-stage hormone receptor-positive tumors treated with adjuvant tamoxifen (20 mg) were evaluated for CYP2D6 genotype and metabolic profiles. Known side effects of tamoxifen treatment, including endometrial thickening, changes in serum lipid levels and bone density, and hepatosteatosis, were evaluated according to the CYP2D6 polymorphism.

RESULT

The distribution of metabolic characteristics in the Turkish population was as follows: 77.1% normal metabolism, 11.5% intermediate metabolism, 5.2% ultrarapid metabolism, and 2.1% poor metabolism. The CYP2D6 genotypes associated with rapid metabolism were CYP2D6 3X*1/*1 duplication (DUP) and CYP2D6 2X*1/*2, while poor metabolism was associated with the genotypes CYP2D6 *3/*4 and CYP2D6 *6/*6. There was no statistically significant relationship between metabolic characteristics and bone density or hepatosteatosis. A statistically significant difference in total cholesterol and triglycerides was detected in lipid profile analysis (p = 0.003, p = 0.02). Assessment of endometrial thickness revealed a significant association of hyperplasia and poor metabolism, and an association between atrophy and ultrarapid metabolism (p = 0.01).

CONCLUSION

Significant development of endometrial hyperplasia was identified among individuals with poor tamoxifen metabolism. As a result, tamoxifen may be a significant predictor of endometrial thickening among individuals with poor metabolic characteristics.

A prospective, randomized study on hepatotoxicity of anastrozole compared with tamoxifen in women with breast cancer

Tamoxifen and anastrozole are widely used as adjuvant treatment for early stage breast cancer, but their hepatotoxicity is not fully defined. We aimed to compare hepatotoxicity of anastrozole with tamoxifen in the adjuvant setting in postmenopausal breast cancer patients. Three hundred and fifty-three Chinese postmenopausal women with hormone receptor-positive early breast cancer were randomized to anastrozole or tamoxifen after optimal primary therapy. The primary end-point was fatty liver disease, defined as a liver–spleen ratio <0.9 as determined using a computed tomography scan. The secondary end-points included abnormal liver function and treatment failure during the 3-year follow up. The cumulative incidence of fatty liver disease after 3 years was lower in the anastrozole arm than that of tamoxifen (14.6% vs 41.1%, P < 0.0001; relative risk, 0.30; 95% CI, 0.21–0.45). However, there was no difference in the cumulative incidence of abnormal liver function (24.6% vs 24.7%, P = 0.61). Interestingly, a higher treatment failure rate was observed in the tamoxifen arm compared with anastrozole and median times to treatment failure were 15.1 months and 37.1 months, respectively (P < 0.0001; HR, 0.27; 95% CI, 0.20–0.37). The most commonly reported adverse events were ‘reproductive system disorders’ in the tamoxifen group (17.1%), and ‘musculoskeletal disorders’ in the anastrozole group (14.6%). Postmenopausal women with hormone receptor-positive breast cancer receiving adjuvant anastrozole displayed less fatty liver disease, suggesting that this drug had a more favorable hepatic safety profile than tamoxifen and may be preferred for patients with potential hepatic dysfunction.

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.

Drug-induced liver injury: Is it somehow foreseeable?

The classic view on the pathogenesis of drug-induced liver injury is that the so-called parent compounds are made hepatotoxic by metabolism (formation of neo-substances that react abnormally), mainly by cytochromes P-450 (CYP), with further pathways, such as mitochondrial dysfunction and apoptosis, also playing a role. Risk factors for drug-induced liver injury include concomitant hepatic diseases, age and genetic polymorphisms of CYP. However, some susceptibility can today be predicted before drug administration, working on the common substrate, by phenotyping and genotyping studies and by taking in consideration patients’ health status. Physicians should always think of this adverse effect in the absence of other clear hepatic disease. Ethical and legal problems towards operators in the health care system are always matters to consider.

Toremifene: an evaluation of its safety profile

Toremifene has been in clinical use for 8 years for the treatment of advanced hormone-sensitive breast cancer and the adjuvant treatment of early breast cancer. More than 350,000 patient treatment years have accumulated, sufficient to allow evaluation of its longer-term safety profile in comparison with tamoxifen and, where possible, with raloxifene and aromatase inhibitors. We reviewed all preclinical and clinical safety data from 1978 to 2004 and comparative clinical safety data between October 1995 and the end of 2004. Secondary endometrial cancer incidence was lower with toremifene than with tamoxifen and was similar to that with raloxifene. It is speculated that toremifene may unmask existing endometrial tumors rather than induce new events. The risk of stroke, pulmonary embolism, and cataract may be lower with toremifene than with tamoxifen and the risk of pulmonary embolism and deep vein thrombosis lower than with raloxifene. Beneficial estrogen agonistic effects were equivalent to those of tamoxifen regarding bone mineral density and superior regarding lipid profiles.

Tamoxifen induced hepatotoxicity in breast cancer patients with pre-existing liver steatosis: the role of glucose intolerance

OBJECTIVE

Tamoxifen induced hepatotoxicity has not been investigated in breast cancer patients with pre-existing liver steatosis. The aim of our study was to investigate the most common predisposing factors for non-alcoholic fatty liver disease in breast cancer patients with liver steatosis, treated with adjuvant tamoxifen therapy, in order to evaluate their role in the appearance of tamoxifen induced hepatotoxicity.

METHODS

Clinical and laboratory evaluation, including an oral glucose tolerance test, was done in 60 women with breast cancer and liver steatosis before the beginning of adjuvant tamoxifen treatment and every 6 months during treatment. Tamoxifen induced hepatotoxicity was defined as abnormal liver function tests during tamoxifen treatment whereas these test results were below the normal range at baseline control. Statistical evaluation of data was performed using parametric methodology (the chi-squared test, and Student's t-test, P < 0.05).

RESULTS

Twenty-six patients (43.3%) exhibited tamoxifen induced hepatotoxicity (group A) whereas 34 (56.7%) did not (group B). The mean overall follow-up period for the whole group was 37.5 months (SD 27.8, range 6-120 months) and did not differ between the two groups (P = 0.055). There was significant statistical difference in body mass index (BMI) and baseline fasting glucose, cholesterol and triglyceride levels between the two groups. Eighteen of 26 patients (69.2%) from group A had impaired glucose tolerance compared with only 8/34 patients (23.5%) from group B (P < 0.001), a finding observed even in BMI matched patients from the two groups (62.5% vs 12.5%, P = 0.002).

CONCLUSIONS

Tamoxifen induced hepatotoxicity is observed in a great proportion of breast cancer patients with pre-existing liver steatosis, especially those with higher BMI and higher glucose and lipid levels at baseline control. Glucose intolerance before the beginning of tamoxifen treatment seems to be a predictor of the hepatotoxicity, unrelated to baseline BMI.