Impact of diet on irinotecan toxicity in mice

Irinotecan-Induced Steatohepatitis: Current Insights

The hepatotoxicity of irinotecan is drawing wide concern nowadays due to the widespread use of this chemotherapeutic against various solid tumors, particularly metastatic colorectal cancer. Irinotecan-induced hepatotoxicity mainly manifests as transaminase increase and steatosis with or without transaminase increase, and is accompanied by vacuolization, and lobular inflammation. Irinotecan-induced steatohepatitis (IIS) increases the risk of morbidity and mortality in patients with colorectal cancer liver metastasis (CRCLM). The major risks and predisposing factors for IIS include high body mass index (BMI) or obesity, diabetes, and high-fat diet. Mitochondrial dysfunction and autophagy impairment may be involved in the pathogenesis of IIS. However, there is currently no effective preventive or therapeutic treatment for this condition. Thus, the precise mechanisms underlying the pathogenesis of IIS should be deciphered for the development of therapeutic drugs. This review summarizes the current knowledge and research progress on IIS.

Discovery of a series of 5-phenyl-2-furan derivatives containing 1,3-thiazole moiety as potent Escherichia coli β-glucuronidase inhibitors

Gut microbial β-glucuronidases have drawn much attention due to their role as a potential therapeutic target to alleviate some drugs or their metabolites-induced gastrointestinal toxicity. In this study, fifteen 5-phenyl-2-furan derivatives containing 1,3-thiazole moiety (1-15) were synthesized and evaluated for their inhibitory effects against Escherichia coli β-glucuronidase (EcGUS). Twelve of them showed satisfactory inhibition against EcGUS with IC₅₀ values ranging from 0.25 μM to 2.13 μM with compound 12 exhibited the best inhibition. Inhibition kinetics studies indicated that compound 12 (K_i = 0.14 ± 0.01 μM) was an uncompetitive inhibitor for EcGUS and molecular docking simulation further predicted the binding model and capability of compound 12 with EcGUS. A preliminary structure-inhibitory activity relationship study revealed that the heterocyclic backbone and bromine substitution of benzene may be essential for inhibition against EcGUS. The compounds have the potential to be applied in drug-induced gastrointestinal toxicity and the findings would help researchers to design and develop more effective 5-phenyl-2-furan type EcGUS inhibitors.

Green tea catechins in combination with irinotecan attenuates tumorigenesis and treatment-associated toxicity in an inflammation-associated colon cancer mice model

BACKGROUND

Administration of green tea (GT) catechins has been reported to ensue antitumor activity in combination with chemotherapeutic drugs against different cancer types. Irinotecan (IRN) is a highly effective chemotherapeutic drug against various types of cancer including colon cancer along with its analogous dose-limiting side effects viz. diarrhea, neutropenia, leucopenia, and non-alcoholic fatty liver disease (NAFLD) as major toxicities.

METHODS

In this study, we investigated the antitumor effects of GT alone or in combination with IRN in inflammation-associated colon cancer mouse model induced by azoxymethane (AOM) and dextran sulfate sodium (DSS). We also evaluated the effect of GT- on IRN-induced toxicity and histopathological alterations. Animals were divided into six groups (n = 5 per group). After induction of cancer model, animals were treated with GT and/or IRN. We observed the inflammation, tumor progression, and ameliorative effects of GT and IRN alone or in combination.

RESULTS

Because of antioxidant potential of GT, IRN-induced toxicity ameliorative effect of GT was also studied in combined treated groups. It was found that co-administration of IRN and GT significantly decreased number of tumors and simultaneously was found to ameliorate diarrhea along with leucopenia and neutropenia. Besides these, mitigation of adenomatous characters and NAFLD was also observed in the IRN- and GT-treated group when analyzed histologically.

CONCLUSIONS

GT significantly reduced the toxicity induced by IRN in terms of diarrhea, neutropenia, leucopenia, and NAFLD and works as an effective anticancer agent as it mitigates histopathology of colon adenocarcinoma.

Irinotecan and berberine co-delivery liposomes showed improved efficacy and reduced intestinal toxicity compared with Onivyde for pancreatic cancer

Onivyde is the first irinotecan (IRI) nanoliposome that could improve pharmacokinetics and tumor biodistribution of irinotecan. Although FDA approves Onivyde for the treatment of pancreatic cancer patients who are not effective for GEM, the gastrointestinal toxicity caused by Onivyde is still a problem to be solved in clinical application. Berberine (BER), an isoquinolone alkaloid extracted from several different plants, has been reported to exhibit beneficial effect in alleviating intestinal mucositis and generating synergistic anticancer effect in combination with cytotoxic drugs. However, its therapeutic effect is affected by the different pharmacokinetic behavior of two drugs. Therefore, we utilized triethylamine-sucrose octasulfate gradient to construct nanoliposomes for co-delivery of irinotecan and berberine, termed as lipBI. This co-delivery nanoliposomes remained the synergistic ratio in the body and improved tumor distribution of IRI and BER. The lipBI significantly inhibited tumor growth in the BXPC-3 pancreatic cancer model compared with Onivyde (p < 0.05) and reduced the gastrointestinal toxicity in mice caused by IRI. Overall, IRI/BER co-loaded liposomes possessed great potential in the treatment of pancreatic cancer.

A NMR study of binding the metabolite of SN38 derivatives to a model nicked DNA decamer mimicking target of Topo I inhibitors

In this account we present NMR based results of the interaction of 7-ethyl-9-hydroxymethyl-10-hydroxycamptothecin (1), a derivative of SN38, with a model nicked DNA decamer mimicking the wild type DNA target of Topoisomerase I inhibitors from the camptothecin family. The title compound 1 can be considered a main metabolite of phase I in the metabolic pathway of camptothecin derivatives bearing the alkylamino substituent. Therefore, its pharmacodynamic properties are of interest. It was established by DOSY (Diffusion Ordered Spectroscopy) that compound 1 forms a fairly stable molecular complex with a model nicked DNA decamer with affinity constant K_a 3.02 mM^-1. The analysis of NOESY experiments revealed intermolecular cross peaks and mutual induced shifts on both interacting components allowing the conclusion that guest molecule 1 is stacking the nitrogen bases inside the nick. MD (Molecular Dynamics) analysis of four possible inclusions of 1 inside the nick allows establishing the detailed geometry of a complex. Two conformations are suggested as the ones best representing the results of molecular modeling reconciled with experimental NOESY results. The aromatic core of both structures is stacking the nitrogen bases in a nick facing the unbroken strand with ring A. The protons in ring E interact with ribose protons of edge bases of a nick. In conclusion, it can be asserted that SN38 derivative 1 can effectively bind the molecular target of Topo I enzyme and play a role as a Topo I inhibitor.

Potential role of drug metabolizing enzymes in chemotherapy-induced gastrointestinal toxicity and hepatotoxicity

INTRODUCTION

Toxicity of chemotherapy drugs is the leading cause of poor therapeutic outcome in many cancer patients. Gastrointestinal (GI) toxicity and hepatotoxicity are among the most common side effects of current chemotherapies. Emerging studies indicate that many chemotherapy-induced toxicities are driven by drug metabolism, but very few reviews summarize the role of drug metabolism in chemotherapy-induced GI toxicity and hepatotoxicity. In this review, we highlighted the importance of drug metabolizing enzymes (DMEs) in chemotherapy toxicity.

AREAS COVERED

Our review demonstrated that altered activity of DMEs play important role in chemotherapy-induced GI toxicity and hepatotoxicity. Besides direct changes in catalytic activities, the transcription of DMEs is also affected by inflammation, cell-signaling pathways, and/or by drugs in cancer patients due to the disease etiology.

EXPERT OPINION

More studies should focus on how DMEs are altered during chemotherapy treatment, and how such changes affect the metabolism of chemotherapy drug itself. This mutual interaction between chemotherapies and DMEs can lead to excessive exposure of parent drug or toxic metabolites which ultimately cause GI adverse effect.

Drug-induced liver injury in obesity and nonalcoholic fatty liver disease

Obesity is commonly associated with nonalcoholic fatty liver (NAFL), a benign condition characterized by hepatic lipid accumulation. However, NAFL can progress in some patients to nonalcoholic steatohepatitis (NASH) and then to severe liver lesions including extensive fibrosis, cirrhosis and hepatocellular carcinoma. The entire spectrum of these hepatic lesions is referred to as nonalcoholic fatty liver disease (NAFLD). The transition of simple fatty liver to NASH seems to be favored by several genetic and environmental factors. Different experimental and clinical investigations showed or suggested that obesity and NAFLD are able to increase the risk of hepatotoxicity of different drugs. Some of these drugs may cause more severe and/or more frequent acute liver injury in obese individuals whereas others may trigger the transition of simple fatty liver to NASH or may worsen hepatic lipid accumulation, necroinflammation and fibrosis. This review presents the available information regarding drugs that may cause a specific risk in the context of obesity and NAFLD. These drugs, which belong to different pharmacological classes, include acetaminophen, halothane, methotrexate, rosiglitazone and tamoxifen. For some of these drugs, experimental investigations confirmed the clinical observations and unveiled different pathophysiological mechanisms which may explain why these pharmaceuticals are particularly hepatotoxic in obesity and NAFLD. Because obese people often take several drugs for the treatment of different obesity-related diseases, there is an urgent need to identify the main pharmaceuticals that may cause acute liver injury on a fatty liver background or that may enhance the risk of severe chronic liver disease.