An adenosine derivative promotes mitochondrial supercomplexes reorganization and restoration of mitochondria structure and bioenergetics in a diethylnitrosamine-induced hepatocellular carcinoma model.

Hepatocellular carcinoma (HCC) progression is associated with dysfunctional mitochondria and bioenergetics impairment. However, no data about the relationship between mitochondrial supercomplexes (hmwSC) formation and ATP production rates in HCC are available. Our group has developed an adenosine derivative, IFC-305, which improves mitochondrial function, and it has been proposed as a therapeutic candidate for HCC. We aimed to determine the role of IFC-305 on both mitochondrial structure and bioenergetics in a sequential cirrhosis-HCC model in rats. Our results showed that IFC-305 administration decreased the number and size of liver tumors, reduced the expression of tumoral markers, and reestablished the typical architecture of the hepatic parenchyma. The livers of treated rats showed a reduction of mitochondria number, recovery of the mtDNA/nDNA ratio, and mitochondrial length. Also, IFC-305 increased cardiolipin and phosphatidylcholine levels and promoted hmwSC reorganization with changes in the expression levels of hmwSC assembly-related genes. IFC-305 in HCC modified the expression of several genes encoding elements of electron transport chain complexes and increased the ATP levels by recovering the complex I, III, and V activity. We propose that IFC-305 restores the mitochondrial bioenergetics in HCC by normalizing the quantity, morphology, and function of mitochondria, possibly as part of its hepatic restorative effect.

Compromised very-low density lipoprotein induced polyunsaturated triglyceride accumulation in N-nitrosodiethylamine-induced hepatic steatosis.

N-Nitrosodiethylamine (NDEA), a carcinogen in some foods and medications, is linked to liver damage similar to non-alcoholic fatty liver disease (NAFLD). This study explores how NDEA disrupts liver lipid metabolism. Sprague-Dawley rats were given two doses of NDEA (100 mg/kg) orally, 24 h apart. Liver response was assessed through tissue staining, blood tests, and biochemical markers, including fatty acids, lipid peroxidation, and serum very-low density lipoprotein (VLDL) levels. Additionally, lipidomic analysis of liver tissues and serum was performed. The results indicated significant hepatic steatosis (fat accumulation in the liver) following NDEA exposure. Blood analysis showed signs of inflammation and liver damage. Biochemical tests revealed decreased liver protein synthesis and specific enzyme alterations, suggesting liver cell injury but maintaining mitochondrial function. Increased fatty acid levels without a rise in lipid peroxidation were observed, indicating fat accumulation. Lipidomic analysis showed increased polyunsaturated triglycerides in the liver and decreased serum VLDL, implicating impaired VLDL transport in liver dysfunction. In conclusion, NDEA exposure disrupts liver lipid metabolism, primarily through the accumulation of polyunsaturated triglycerides and impaired fat transport. These findings provide insight into the mechanisms of NDEA-induced liver injury and its progression to hepatic steatosis.

Linagliptin, a DPP-4 inhibitor, activates AMPK/FOXO3a and suppresses NFκB to mitigate the debilitating effects of diethylnitrosamine exposure in rat liver: Novel mechanistic insights.

Accumulating evidence suggests that dysregulation of FOXO3a plays a significant role in the progression of various malignancies, including hepatocellular carcinoma (HCC). FOXO3a inactivation, driven by oncogenic stimuli, can lead to abnormal cell growth, suppression of apoptosis, and resistance to anticancer drugs. Therefore, FOXO3a emerges as a potential molecular target for the development of innovative treatments in the era of oncology. Linagliptin (LNGTN), a DPP-4 inhibitor known for its safe profile, has exhibited noteworthy anti-inflammatory and anti-oxidative properties in previous in vivo studies. Several potential molecular mechanisms have been proposed to explain these effects. However, the capacity of LNGTN to activate FOXO3a through AMPK activation has not been investigated. In our investigation, we examined the potential repurposing of LNGTN as a hepatoprotective agent against diethylnitrosamine (DENA) intoxication. Additionally, we assessed LNGTN's impact on apoptosis and autophagy. Following a 10-week administration of DENA, the liver underwent damage marked by inflammation and early neoplastic alterations. Our study presents the first experimental evidence demonstrating that LNGTN can reinstate the aberrantly regulated FOXO3a activity by elevating the nuclear fraction of FOXO3a in comparison to the cytosolic fraction, subsequent to AMPK activation. Moreover, noteworthy inactivation of NFκB induced by LNGTN was observed. These effects culminated in the initiation of apoptosis, the activation of autophagy, and the manifestation of anti-inflammatory, antiproliferative, and antiangiogenic outcomes. These effects were concomitant with improved liver function and microstructure. In conclusion, our findings open new avenues for the development of novel therapeutic strategies targeting the AMPK/FOXO3a signaling pathway in the management of chronic liver damage.

Diethylnitrosamine Induction of Hepatocarcinogenesis in Mice.

Diethylnitrosamine (DEN) is a chemical hepatocarcinogenic agent that triggers a large array of oncogenic mutations after a single injection. Initiated hepatocytes subsequently undergo clonal expansion within a proliferative environment, rendering the DEN model a comprehensive carcinogen. In rodent studies, DEN finds extensive utility in experimental liver cancer research, mimicking several aspects of human hepatocellular carcinoma (HCC), including angiogenesis, metabolic reprogramming, immune exhaustion, and the ability to metastasize. Beyond the wealth of scientific insights gleaned from this model, the objective of this chapter is to review morphological, genomic, and immunological characteristics associated to DEN-induced HCC. Furthermore, this chapter provides a detailed procedural guide to effectively induce hepatocarcinogenesis in mice through a single intraperitoneal injection of DEN.

Diethylnitrosamine-Induced Liver Tumorigenesis in Mice Under High-Hat High-Sucrose Diet: Stepwise High-Resolution Ultrasound Imaging and Histopathological Correlations.

The hepatotoxic N-nitroso compound diethylnitrosamine (DEN) administered intraperitoneally (i.p.) induces liver neoplasms in rodents that reproducibly recapitulate some aspects of human hepatocarcinogenesis. In particular, DEN drives the stepwise formation of pre-neoplastic and neoplastic (benign or malignant) hepatocellular lesions reminiscent of the initiation-promotion-progression sequence typical of chemical carcinogenesis. In humans, the development of hepatocellular carcinoma (HCC) is also a multi-step process triggered by continuous hepatocellular injury, chronic inflammation, and compensatory hyperplasia that fuel the emergence of dysplastic liver lesions followed by the formation of early HCC. The DEN-induced liver tumorigenesis model represents a versatile preclinical tool that enables the study of many tumor development modifiers (genetic background, gene knockout or overexpression, diets, pollutants, or drugs) with a thorough follow-up of the multistage process on live animals by means of high-resolution imaging. Here, we provide a comprehensive protocol for the induction of hepatocellular neoplasms in wild-type C57BL/6J male mice following i.p. DEN injection (25 mg/kg) at 14 days of age and 36 weeks feeding of a high-fat high-sucrose (HFHS) diet. We emphasize the use of ultrasound liver imaging to follow tumor development and provide histopathological correlations. We also discuss the extrinsic and intrinsic factors known to modify the course of liver tumorigenesis in this model.

Loss of hepatic Sirt7 accelerates diethylnitrosamine (DEN)-induced formation of hepatocellular carcinoma by impairing DNA damage repair.

The mammalian sirtuin family (SIRT1-SIRT7) has shown diverse biological roles in the regulation and maintenance of genome stability under genotoxic stress. SIRT7, one of the least studied sirtuin, has been demonstrated to be a key factor for DNA damage response (DDR). However, conflicting results have proposed that Sirt7 is an oncogenic factor to promote transformation in cancer cells. To address this inconsistency, we investigated properties of SIRT7 in hepatocellular carcinoma (HCC) regulation under DNA damage and found that loss of hepatic Sirt7 accelerated HCC progression. Specifically, the number, size, and volume of hepatic tumor colonies in diethylnitrosamine (DEN) injected Sirt7-deficient liver were markedly enhanced. Further, levels of HCC progression markers and pro-inflammatory cytokines were significantly elevated in the absence of hepatic Sirt7, unlike those in the control. In chromatin, SIRT7 was stabilized and colocalized to damage site by inhibiting the induction of γH2AX under DNA damage. Together, our findings suggest that SIRT7 is a crucial factor for DNA damage repair and that hepatic loss-of-Sirt7 can promote genomic instability and accelerate HCC development, unlike early studies describing that Sirt7 is an oncogenic factor [BMB Reports 2024; 57(2): 98-103].

Structural abnormality of hepatic glycogen in rat liver with diethylnitrosamine-induced carcinogenic injury.

Growing evidence confirms associations between glycogen metabolic re-wiring and the development of liver cancer. Previous studies showed that glycogen structure changes abnormally in liver diseases such as cystic fibrosis, diabetes, etc. However, few studies focus on glycogen molecular structural characteristics during liver cancer development, which is worthy of further exploration. In this study, a rat model with carcinogenic liver injury induced by diethylnitrosamine (DEN) was successfully constructed, and hepatic glycogen structure was characterized. Compared with glycogen structure in the healthy rat liver, glycogen chain length distribution (CLD) shifts towards a short region. In contrast, glycogen particles were mainly present in small-sized ß particles in DEN-damaged carcinogenic rat liver. Comparative transcriptomic analysis revealed significant expression changes of genes and pathways involved in carcinogenic liver injury. A combination of transcriptomic analysis, RT-qPCR, and western blot showed that the two genes, Gsy1 encoding glycogen synthase and Gbe1 encoding glycogen branching enzyme, were significantly altered and might be responsible for the structural abnormality of hepatic glycogen in carcinogenic liver injury. Taken together, this study confirmed that carcinogenic liver injury led to structural abnormality of hepatic glycogen, which provided clues to the future development of novel drug targets for potential therapeutics of carcinogenic liver injury.

Obesity phenotype induced by high-fat diet promotes diethylnitrosamine (DEN)-induced precancerous lesions by M1 macrophage polarization in mice liver.

Liver precancerous lesions are the key to improving the efficacy of cancer treatment because of the extremely poor prognosis of HCC patients in moderate and late stages. Obesity-related HCC progression is closely related to the inflammatory microenvironment, in which macrophages are one of the major constituents. In the present study, we ask whether obesity promotes diethylnitrosamine (DEN)-induced precancerous lesions by M1 macrophage polarization. First, an association between obesity and liver precancerous lesions was determined by histopathological observations, immunochemistry and immunoblotting. The characteristics of early precancerous lesions (trabecular thickening) appeared earlier eight weeks in obese mice than in normal diet mice after DEN induction. The glutathione S-transferase placental-1 (Gstp 1) and alpha-fetoprotein (AFP) expression in obese mice after DEN induction was higher than that in the same period after DEN injection in normal diet mice. Furthermore, there was a significant increase in the total macrophage number (F4/80+) of DEN and M1 macrophage number (CD86+F4/80+) in obese mice compared with that in normal diet mice. Besides, the expressions of four pro-inflammatory factors in DEN-induced obese mice were significantly higher compared with that in normal diet mice. Additionally, angiogenesis was revealed by immunostaining assay to be associated with the inflammatory response. All the results demonstrate that obesity promotes DEN-induced precancerous lesions by inducing M1 macrophage polarization and angiogenesis.

Improvement of rat hepatocellular carcinoma model induced by diethylnitrosamine.

OBJECTIVE: To construct a new diethylnitrosamine (DEN)-induced rat hepatocellular carcinoma (HCC) model with short induction time, high incidence, and survival rate. METHODS: 60 male Sprague-Dawley rats were randomly divided into 4 groups: the control group, the model A (MA) group, the model B (MB) group, and the model C (MC) group. The control group was intraperitoneally injected with 0.9% saline for 6 weeks. The MA group was injected with the DEN solution at 30 mg/kg three times a week for 6 weeks. The MB group was injected with the DEN solution at 30 mg/kg three times a week for 6 weeks, and discontinued the induction for 2 weeks. The MC group was injected with the DEN solution at 30 mg/kg three times a week for 8 weeks. The levels of albumin (ALB), alanine transaminase (ALT), and aspartate aminotransferase (AST) in serum were assayed. Meanwhile, the pathological conditions, apoptosis of hepatocytes, expression of NF-κBp65, and the reactive oxygen species level were detected. RESULTS: All rats in the control group and the MA group survived, and none of the rats occurred HCC. HCC occurred in rats of the MB group and the MC group. The serum ALB level in the MB group was higher than that in the MC group. The serum ALT and AST levels and the number of proliferating and apoptotic hepatocyte cells in the MB group were lower than those in the MC group. The expression of ROS- and NF-κBp6- positive cells in the MA group, MB group, and MC group were significantly higher than that of the control group. CONCLUSION: This study developed a new DEN-induced rat HCC model with short induction time, high incidence, and survival rate. NF-κB pathway may be one of the main pathways involved in the development of this model.

Ames test study designs for nitrosamine mutagenicity testing: qualitative and quantitative analysis of key assay parameters.

The robust control of genotoxic N-nitrosamine (NA) impurities is an important safety consideration for the pharmaceutical industry, especially considering recent drug product withdrawals. NAs belong to the 'cohort of concern' list of genotoxic impurities (ICH M7) because of the mutagenic and carcinogenic potency of this chemical class. In addition, regulatory concerns exist regarding the capacity of the Ames test to predict the carcinogenic potential of NAs because of historically discordant results. The reasons postulated to explain these discordant data generally point to aspects of Ames test study design. These include vehicle solvent choice, liver S9 species, bacterial strain, compound concentration, and use of pre-incubation versus plate incorporation methods. Many of these concerns have their roots in historical data generated prior to the harmonization of Ames test guidelines. Therefore, we investigated various Ames test assay parameters and used qualitative analysis and quantitative benchmark dose modelling to identify which combinations provided the most sensitive conditions in terms of mutagenic potency. Two alkyl-nitrosamines, N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) were studied. NDMA and NDEA mutagenicity was readily detected in the Ames test and key assay parameters were identified that contributed to assay sensitivity rankings. The pre-incubation method (30-min incubation), appropriate vehicle (water or methanol), and hamster-induced liver S9, alongside Salmonella typhimurium strains TA100 and TA1535 and Escherichia coli strain WP2uvrA(pKM101) provide the most sensitive combination of assay parameters in terms of NDMA and NDEA mutagenic potency in the Ames test. Using these parameters and further quantitative benchmark dose modelling, we show that N-nitrosomethylethylamine (NMEA) is positive in Ames test and therefore should no longer be considered a historically discordant NA. The results presented herein define a sensitive Ames test design that can be deployed for the assessment of NAs to support robust impurity qualifications.

Hepatoprotective effects of aspirin on diethylnitrosamine-induced hepatocellular carcinoma in rats by reducing inflammation levels and PD-L1 expression.

Aspirin, as a widely used anti-inflammatory drug, has been shown to exert anti-cancer effects in a variety of cancers. PD-L1 is widely expressed in tumor cells and inhibits anti-tumor immunity. This study aims to clarify whether aspirin exerts its anti-hepatocellular carcinoma (HCC) effect by inhibiting PD-L1 expression. The rat model of HCC was established by drinking 0.01% diethylnitrosamine (DEN), and aspirin was given by gavage. The gross and blood biochemical indexes of rats were analyzed. CD4 and CD8 expression in liver tissues were investigated by immunohistochemistry. CCK8 assay was used to detect the inhibitory effect of aspirin on the proliferation of HCC cells. The regulatory effect of aspirin on PD-L1 expression was analyzed by western blot. As a result, the tumor number and liver weight ratio in the DEN + ASA group were lower than those in the DEN group (P = 0.006, P = 0.046). Compared with the DEN group, the expression of CD4 in the DEN + ASA group was significantly increased, while CD8 was decreased (all P < 0.01). Biochemical indexes showed that there were differences in all indexes between the DEN and control group (P < 0.05). The levels of DBIL, ALP, and TT in the DEN + ASA group were lower than those in the DEN group (P = 0.038, P = 0.042, P = 0.031). In the DEN group, there was an obvious fibrous capsule around the tumor, and the portal vein was dilated. The pathological changes were mild in the DEN + ASA group. Compared with the DEN group, the expression of PD-L1 in liver tissue of the DEN + ASA group was decreased (P = 0.0495). Cytological experiments further showed that aspirin could inhibit the proliferation and PD-L1 expression in Hep G2 and Hep 3B cells. In conclusion, aspirin can inhibit the proliferation of HCC cells and reduce tumor burden by reducing inflammation and targeting PD-L1.

Estrogen Attenuates Diethylnitrosamine-Induced Hepatocellular Carcinoma in Female Rats via Modulation of Estrogen Receptor/FASN/CD36/IL-6 Axis.

This study was designed to evaluate the potential protective impact of estrogen and estrogen receptor against diethylnitrosamine (DEN)-induced hepatocellular carcinoma (HCC) in rats. The levels of liver injury serum biomarkers, liver content of interleukin-6 (IL-6), relative liver weight and distortion of liver histological pictures were significantly increased in ovariectomized (OVX) rats and SHAM rats that received DEN alone and were further exaggerated when DEN was combined with fulvestrant (F) compared to non-DEN treated rats. The OVX rats showed higher insults than SHAM rats. The tapering impact on these parameters was clear in OVX rats that received estradiol benzoate (EB), silymarin (S) or orlistat (ORS). The immunohistochemistry and/or Western blot analysis of liver tissues showed a prominent increase in fatty acid synthase (FASN) and cluster of differentiation 36 (CD36) expressions in OVX and SHAM rats who received DEN and/ or F compared to SHAM rats. In contrast to S, treatment of OVX rats with EB mitigated DEN-induced expression of FASN and CD36 in liver tissue, while ORS improved DEN-induced expression of FASN. In conclusion, the protective effect against HCC was mediated via estrogen receptor alpha (ER-α) which abrogates its downstream genes involved in lipid metabolism namely FASN and CD36 depriving the tumor from survival vital energy source. In addition, ORS induced similar mitigating effect against DEN-induced HCC which could be attributed to FASN inhibition and anti-inflammatory effect. Furthermore, S alleviated DEN-induced HCC, independent of its estrogenic effect.

Novel miRNA-based drug CD5-2 reduces liver tumor growth in diethylnitrosamine-treated mice by normalizing tumor vasculature and altering immune infiltrate.

Introduction: Liver cancers exhibit abnormal (leaky) vasculature, hypoxia and an immunosuppressive microenvironment. Normalization of tumor vasculature is an emerging approach to treat many cancers. Blockmir CD5-2 is a novel oligonucleotide-based inhibitor of the miR-27a interaction with VE-Cadherin, the endothelial-specific cadherin. The combination of a vasoactive medication with inhibition of immune checkpoints such as programmed cell death protein 1 (PD1) has been shown to be effective in treating liver cancer in humans. We aimed to study the effect of CD5-2 combined with checkpoint inhibition (using an antibody against PD1) on liver tumor growth, vasculature and immune infiltrate in the diethylnitrosamine (DEN)-induced liver tumor mouse model. Methods: We first analyzed human miR-27a and VE-Cadherin expression data from The Cancer Genome Atlas for hepatocellular carcinoma. CD5-2 and/or anti-PD1 antibody were given to the DEN-treated mice from age 7-months until harvest at age 9-months. Tumor and non-tumor liver tissues were analyzed using histology, immunohistochemistry, immunofluorescence and scanning electron microscopy. Results: Human data showed high miR-27a and low VE-Cadherin were both significantly associated with poorer prognosis. Mice treated with CD5-2 plus anti-PD1 antibody had significantly smaller liver tumors (50% reduction) compared to mice treated with either agent alone, controls, or untreated mice. There was no difference in tumor number. Histologically, tumors in CD5-2-treated mice had less leaky vessels with higher VE-Cadherin expression and less tumor hypoxia compared to non-CD5-2-treated mice. Only tumors in the combination CD5-2 plus anti-PD1 antibody group exhibited a more favorable immune infiltrate (significantly higher CD3+ and CD8+ T cells and lower Ly6G+ neutrophils) compared to tumors from other groups. Discussion: CD5-2 normalized tumor vasculature and reduced hypoxia in DEN-induced liver tumors. CD5-2 plus anti-PD1 antibody reduced liver tumor size possibly by altering the immune infiltrate to a more immunosupportive one.

Comparison of the transgenic rodent mutation assay, error corrected next generation duplex sequencing, and the alkaline comet assay to detect dose-related mutations following exposure to N-nitrosodiethylamine.

N-Nitrosodiethylamine (NDEA), a well-studied N-nitrosamine, was tested in rats to compare the dose-response relationship of three genotoxicity endpoints. Mutant / mutation frequencies were determined using the transgenic rodent (TGR) gene mutation assay and error corrected next generation sequencing (ecNGS) (i.e., duplex sequencing (DS)), and genetic damage was detected by the alkaline comet assay. Big Blue® (cII Locus) animals (n = 6 per dose group) were administered doses of 0.001, 0.01, 0.1, 1, 3 mg/kg/day NDEA by oral gavage. Samples were collected for cII mutation and DS analyses following 28-days of exposure and 3 days recovery. In a separate study, male Sprague-Dawley (SD) rats (n = 6 per dose group) were administered the same doses by oral gavage for two consecutive days and then samples collected for the alkaline comet assay. A dose-related increase in mutant / mutation frequencies of the liver but not duodenum was observed using the TGR assay and DS with DS resulting in a slightly more sensitive response, with a lower benchmark dose (BMD). In addition, a dose-related increase in percent tail DNA was observed in the liver using the alkaline comet assay. Therefore, DS and comet assays showed good utility for hazard identification and dose-response analysis of a representative N-nitrosamine comparable to the TGR gene mutation assay.

ZEB1 Transcriptionally Activates PHGDH to Facilitate Carcinogenesis and Progression of HCC.

BACKGROUND & AIMS: Phosphoglycerate dehydrogenase (PHGDH), the rate-limiting enzyme of the de novo serine synthesis pathway (SSP), has been implicated in the carcinogenesis and metastasis of hepatocellular carcinoma (HCC) because of its excessive expression and promotion of SSP. In previous experiments we found that SSP flux was diminished by knockdown of zinc finger E-box binding homeobox 1 (ZEB1), a stimulator of HCC metastasis, but the underlying mechanism remains largely unknown. Here, we aimed to determine how SSP flux is regulated by ZEB1 and the contribution of such regulation to carcinogenesis and progression of HCC. METHODS: We used genetic mice with Zeb1 knockout in liver specifically to determine whether Zeb1 deficiency impacts HCC induced by the carcinogen diethylnitrosamine plus CCl4. We explored the regulatory mechanism of ZEB1 in SSP flux using uniformly-labeled [13C]-glucose tracing analyses, liquid chromatography-mass spectrometry, real-time quantitative polymerase chain reaction, luciferase report assay, and chromatin immunoprecipitation assay. We determined the contribution of the ZEB1-PHGDH regulatory axis to carcinogenesis and metastasis of HCC by cell counting assay, methyl thiazolyl tetrazolium (MTT) assay, scratch wound assay, Transwell assay, and soft agar assay in vitro, orthotopic xenograft, bioluminescence, and H&E assays in vivo. We investigated the clinical relevance of ZEB1 and PHGDH by analyzing publicly available data sets and 48 pairs of HCC clinical specimens. RESULTS: We identified that ZEB1 activates PHGDH transcription by binding to a nonclassic binding site within its promoter region. Up-regulated PHGDH augments SSP flux to enable HCC cells to be more invasive, proliferative, and resistant to reactive oxygen species and sorafenib. Orthotopic xenograft and bioluminescence assays have shown that ZEB1 deficiency significantly impairs the tumorigenesis and metastasis of HCC, and such impairments can be rescued to a large extent by exogenous expression of PHGDH. These results were confirmed by the observation that conditional knockout of ZEB1 in mouse liver dramatically impedes carcinogenesis and progression of HCC induced by diethylnitrosamine/CCl4, as well as PHGDH expression. In addition, analysis of The Cancer Genome Atlas database and clinical HCC samples showed that the ZEB1-PHGDH regulatory axis predicts poor prognosis of HCC. CONCLUSIONS: ZEB1 plays a crucial role in stimulating carcinogenesis and progression of HCC by activating PHGDH transcription and subsequent SSP flux, deepening our knowledge of ZEB1 as a transcriptional factor in fostering the development of HCC via reprogramming the metabolic pathway.

The anticarcinogenic effect of eugenol on lung cancer induced by diethylnitrosamine/2-acetylaminofluorene in Wistar rats: insight on the mechanisms of action.

This study was designed to assess the ameliorative effects of eugenol and to propose the possible mechanisms of action of eugenol in diethylnitrosamine (DENA)/acetylaminofluorene (AAF)-caused lung cancer in Wistar rats. To induce lung cancer, DENA at a dose of 150 mg/kg body weight (b.wt) for 2 weeks were intraperitoneally injected once each week and AAF was administered orally at a dose of 20 mg/kg b.wt. four times each week for the next 3 weeks. DENA/AAF-administered rats were orally supplemented with eugenol at a dose of 20 mg/kg b.wt administered once a day until 17 weeks starting from the 1st week of DENA administration. Lung histological lesions, including sheets of tumor cells, micropapillary adenocarcinoma, and apoptotic cells, resulting from the DENA/AAF dosage, were ameliorated by eugenol treatment. However, a significant drop in the levels of LPO in the lungs and a remarkable rise in GSH content and GPx and SOD activities were observed in DENA/AAF-administered rats treated with eugenol compared with those in DENA/AAF-administered controls. Moreover, in DENA/AAF-administered rats, eugenol supplementation significantly reduced TNF-α and IL-1ß levels and mRNA expression levels of NF-κB, NF-κB p65, and MCP-1 but significantly elevated the level of Nrf2. Furthermore, the DENA/AAF-administered rats treated with eugenol exhibited a significant downregulation of Bcl-2 expression levels in addition to a significant upregulation in P53 and Bax expression levels. Otherwise, the administration of DENA/AAF elevated the protein expression level of Ki-67, and this elevation was reversed by eugenol treatment. In conclusion, eugenol has effective antioxidant, anti-inflammatory, proapoptotic, and antiproliferative properties against lung cancer.

Chronic Administration of Diethylnitrosamine and 2-Acetylaminofluorene Induces Hepatocellular Carcinoma in Wistar Rats.

This study aimed to analyze the biochemical, histological, and gene expression alterations produced in a hepatocarcinogenesis model induced by the chronic administration of diethylnitrosamine (DEN) and 2-acetylaminofluorene (2-AAF) in Wistar rats. Thirteen rats weighing 180 to 200 g were divided into two groups: control and treated. Rats in the treated group were administered an intraperitoneal (i.p.) injection of DEN (50 mg/kg/week) and an intragastric (i.g.) dose of 2-AAF (25 mg/kg/week) for 18 weeks. The treated group had significant increases in their total cholesterol, HDL-C, AST, ALT, ALKP, and GGT levels. Furthermore, a histological analysis showed the loss of normal liver architecture with nuclear pleomorphism in the hepatocytes, atypical mitosis, and fibrous septa that were distributed between the portal triads and collagen fibers through the hepatic sinusoids. The gene expressions of 24 genes related to fibrosis, inflammation, apoptosis, cell growth, angiogenesis, lipid metabolism, and alpha-fetoprotein (AFP) were analyzed; only TGFß, COL1α1, CYP2E1, CAT, SOD, IL6, TNF-α, and ALB showed significant differences when both groups were compared. Additionally, lung histopathological alterations were found in the treated group, suggesting metastasis. In this model, the chronic administration of DEN+2-AAF induces characteristic alterations of hepatocellular carcinoma in Wistar rats without AFP gene expression changes, highlighting different signatures in hepatocellular carcinoma heterogeneity.

Protective effects of butylated hydroxytoluene on the initiation of N-nitrosodiethylamine-induced hepatocellular carcinoma in albino rats.

Diethylnitrosamine (DEN), a hepatocarcinogen, is found in a variety of smoked and fried foods and was reported to be hepatotoxic in mice. Butylated hydroxytoluene (BHT) is a potent antioxidant used in cosmetic formulations and as a food additive and preservative. As a result, BHT was studied as a potential inhibitor in the early stages of diethylnitrosamine (DEN)-induced HCC. Male Wistar albino rats (n = 24) were equally subdivided. Group 1 was the negative control; Group 2 and 3 administered BHT and DEN, respectively; Group 4 received BHT followed by DEN. Blood samples and rat livers were taken for biochemical and histological investigation. Hepatotoxicity was assessed by increased liver enzymes and HCC indicators, along with reduced antioxidant and pro-apoptotic factors. AFP, AFPL3, GPC3, GSH, SOD, MDA, CASP3 and BAX expression increased significantly after DEN treatment. DEN also reduced GPx, CAT, and CYP2E1 activity, and BCl-2 expression. Moreover, in the hepatic parenchyma, the DEN caused histological alterations. Pretreatment with BHT enhanced antioxidant status while preventing histopathological and most biochemical alterations. BHT pretreatment suppresses DEN-initiated HCC by decreasing oxidative stress, triggering intrinsic mitotic apoptosis, and preventing histopathological changes in liver tissue.

In silico and in vivo hepatoprotective activity of the synthesized 5-benzylidene-2-thiohydantoin against diethylnitrosamine-induced liver injury in a rat model.

In the present study, the hepatoprotective effect of 5-benzylidine-2-thiohydantoin (5B2T), a unique derivative of the thiohydantoin group, on liver injury induced by diethylnitrosamine (DEN) in male rats was investigated. The experimental animals were divided into three groups, each with 14 rats. Rats in group I were considered to be controls and received only 10% Tween 80. Rats in group II were injected with 200 mg/kg DEN intraperitoneally. Rats in group III were injected with a single dose of DEN 200 mg/kg intraperitoneally and received the treatment orally (50 mg/kg, 5B2T) for two durations, 3 and 6 weeks. At the end of the experiment, blood was collected for the analysis of liver function and pro-inflammatory cytokine IL-6 and tumor necrosis factor α (TNF-α) levels. Additionally, liver specimens were used for histopathological examination and immunohistochemistry. The single intraperitoneal injection of 200 mg/kg DEN into rats resulted in significant elevation of serum enzyme levels of AST, ALT and ALP, which are indicators of hepatocellular damage, along with elevation in TNF-α and IL-6 in the DEN group. The results of both LFTs and ELISA in the treatment group showed improvements and a decline in the levels of the markers. Histopathological examination showed fibrosis, necrosis and infiltration of inflammatory cells in the DEN group, with lower intensity in the treatment group. The results of immunohistochemical staining revealed strong positive staining of both HSA and Ki-67 antibodies in the DEN group, with much lower intensity in the treatment group. The results of the docking study indicated that 5B2T has a remarkable interaction with TNF-α (PDB ID: 1TNF) and human IL-6 (PDB ID: 1IL6) with binding site energies of - 7.1 and - 6.1 (kcal/mol), respectively. The correct absorption and binding between the drug and the receptor was evaluated through computerized molecular docking by using the AutoDock program. The conclusion of the results from the current study reflected the interesting hepatoprotective abilities of 5B2T against DEN-induced hepatocellular damage and cancer in experimental rats.

Saroglitazar suppresses the hepatocellular carcinoma induced by intraperitoneal injection of diethylnitrosamine in C57BL/6 mice fed on choline deficient, l-amino acid- defined, high-fat diet.

BACKGROUND: Saroglitazar is a novel PPAR-α/γ agonist with predominant PPAR-α activity. In various preclinical models, saroglitazar has been shown to prevent & reverse symptoms of NASH. In view of these observations, and the fact that NASH is a progressive disease leading to HCC, we hypothesized that saroglitazar may prevent the development of HCC in rodents. METHODS: HCC was induced in C57BL/6 mice by a single intraperitoneal injection of 25 mg/kg diethylnitrosamine (DEN) at the age of 4 weeks and then feeding the animal a choline-deficient, L-amino acid- defined, high-fat diet (CDAHFD) for the entire study duration. Eight weeks after initiation of CDAHFD, saroglitazar (1 and 3 mg/kg) treatment was started and continued for another 27 weeks. RESULTS: Saroglitazar treatment significantly reduced the liver injury markers (serum ALT and AST), reversed hepatic steatosis and decreased the levels of pro-inflammatory cytokines like TNF-α in liver. It also resulted in a marked increase in serum adiponectin and osteopontin levels. All disease control animals showed hepatic tumors, which was absent in saroglitazar (3 mg/kg)- treatment group indicating 100% prevention of hepatic tumorigenesis. This is the first study demonstrating a potent PPARα agonist causing suppression of liver tumors in rodents, perhaps due to a strong anti-NASH activity of Saroglitazar that overrides its rodent-specific peroxisome proliferation activity. CONCLUSION: The data reveals potential of saroglitazar for chemoprevention of hepatocellular carcinoma in patients with NAFLD/NASH.