In silico investigation of the role of miRNAs in a possible developmental origin of prostate cancer in F1 and F2 offspring of mothers exposed to a phthalate mixture

A previous study using miRNA sequencing revealed that exposure to a mixture of phthalates during pregnancy and lactation dysregulated rno-miR-184 and rno-miR-141-3p in the ventral prostate (VP) of offspring. Here, rno-miR-184 and rno-miR-141-3 expressions were obtained by RT-qPCR in the VP of F1 males as well as in F2 offspring, aiming to establish a relationship with possible oncogenic targets through in silico analyses with multigenerational approach. Additionally, some targets were measured by western blots to highlight a possible relationship between the deregulated miRNAs and some of their targets. VP samples from rats exposed to a mixture of phthalates maternally during pregnancy and lactation (GD10 to PND21-F1) and VP from offspring (F2) were examined. The phthalate mixture at both concentrations (20 μg and 200 mg/kg/day) increased the expression of both miRNAs in the F1 (PND22 and 120) and F2 (descendants of F1-treated males) prostate. Target prediction analysis revealed that both microRNAs are responsible for modulating the expression and synthesis of 40 common targets. A phthalate target association analysis and the HPA database showed an interesting relationship among these possible miRNAs modulated targets with prostate adenocarcinoma and other oncogenic processes. Western blots showed alteration in P63, P53, WNT5, and STAT3 expression, which are targeted by the miRNAs, in the VP of F1/F2 males. The data draw attention to the epigenetic modulation in the prostate of descendants exposed to phthalates and adds to one of the few currently found in the literature to point to microRNAs signature as biomarkers of exposure to plasticizers.

An overview of chemically induced rodent models for sporadic colorectal cancer: Histopathological and translational perspectives

Globally, colorectal cancer (CRC) is one of the most frequently diagnosed human gastrointestinal neoplasia and the second leading cause of cancer-related death in both men and women. Despite considerable efforts currently devoted to the study of the biology and treatment of CRC, patient prognosis and survival are still poor. Sporadic CRC is a complex multistep disease and usually emerges in the setting of lifestyle and dietary changes mainly observed in industrialized countries with high human development index (HDI) (westernized style). The molecular pathogenesis of sporadic CRC presents genetic heterogeneity with APC, RAS, PIK3CA, TGFBR, SMAD4, and TP53 mutations usually detected during the progression of this malignancy. The establishment of sporadic CRC models has become essential for both basic and translational research to improve our understanding of the pathophysiology, unravel new molecular drivers, and preventive/therapeutic improvement of this malignancy. Chemically induced rodent models of sporadic CRC recapitulate most key morphological and genetic/epigenetic events observed during the promotion and progression of this malignancy, establishing effective diagnostic and prevention strategies to be translated into clinical practice. The present review gathers the main features of the state-of-the-art evidence on chemically induced rodent models, widely applied for translational modelling of sporadic CRC with a specific focus on histopathology and prevention perspectives. Our narrative review reinforces the persistent value of these bioassays and encourages the use of multimodel strategies for further investigations.

A mixture of glyphosate and 2,4-D herbicides enhances the deleterious reproductive outcomes induced by Western diet in obese male mice

The consumption of Western diet (WD) - enriched in fats and sugars - is associated with overweight, obesity and male reproductive disorders. In addition to WD intake, crops and dairy products display residues of herbicides, including glyphosate and 2,4-D that are widely applied worldwide. The concomitant exposure to WD and herbicides - mimicking contemporary scenarios - is not fully investigated. Thus, we evaluated the effects of glyphosate and 2,4-D, alone or in mixture, on WD-induced alterations in the male genital system. Male C57BL6J mice were submitted to WD (chow containing 20% lard, 0.2% cholesterol, 20% sucrose, and high sugar solution with 23.1 and 18.9 g/L of D-fructose and D-glucose) for 6 months. Concomitantly to WD, the animals received glyphosate (0.05, 5, or 50 mg/kg/day), 2,4-D (0.02, 2 or 20 mg/kg/day) or their mixture (0, 05 + 0.02, 5 + 2, or 50 + 20 mg/kg/day) by intragastrical administration (5×/week). Doses were based on Acceptable Daily Intake (ADIs) or No Observed Adverse Effect Level (NOAEL) values. Herbicide exposure did not alter the WD-induced obesity, hypercholesterolemia and hyperglycemia. WD induced sperm cell abnormalities, reduced the number, volume and area of Leydig cells, enhanced the frequency of epididymal abnormalities, decreased the proliferation in both germinal and epididymal epithelia, and reduced the number of androgen receptor (AR) positive epididymal cells. Remarkably, the herbicide mixtures promoted such WD-induced effects: increased the frequency of sperm cell and epididymal abnormalities (absence of sperm, cytoplasmic vacuoles, and clear cell hypertrophy) (5 + 2 and 50 + 20 doses); decreased Leydig cell nuclei volume and area (5 + 2 and 50 + 20 doses), reduced epididymal cell proliferation (all mixtures), and AR expression (50 + 20 dose). In addition, herbicide mixtures reduced serum testosterone levels (5 + 2 and 50 + 20 doses). Our findings indicate that the mixture of glyphosate and 2,4-D herbicides, mimicking environmentally relevant scenarios, promotes WD-induced changes in the male genital system.

Modifying effects of 2,4-D and Glyphosate exposures on gut-liver-adipose tissue axis of diet-induced non-alcoholic fatty liver disease in mice

Nonalcoholic fatty liver disease (NAFLD), which is linked to western diet (WD) intake, affects 30% of the world's population and involves the crosstalk of liver steatosis, hypertrophy/inflammation of adipose tissue and deregulation of gut microbiome. Glyphosate and 2,4-D are some of the most applied herbicides worldwide, and their roles in NAFLD have not been investigated. Thus, the present study evaluated whether glyphosate and 2,4-D, in single or mixed exposure, alter WD-induced NAFLD in a mouse model. Male C57Bl/6 mice (n = 10/group) received a fat (30% lard, 0.02% cholesterol), and sucrose-rich diet (20%) and high sugar solution (23.1 and 18.9 g/L of fructose and glucose) for 6 months. Simultaneously, animals received glyphosate (0.05 or 5 mg/kg/day), 2,4-D (0.02 or 2 mg/kg/day), or their combination (0.05 +0.02 or 5 +2 mg/kg/day) by intragastrical administration (5 ×/week). Doses were based on the Acceptable Daily Intake (ADIs) or No Observed Adverse Effect Level (NOAEL) levels. Herbicide exposures featured differential responses. WD-induced obesity, hypercholesterolemia, and hyperglycemia remained unaltered. Compared to the group receiving only WD, only the concomitant exposure to WD and 2,4-D (2 mg) enhanced the percentage of mice with moderate/severe hepatic inflammation, CD68 macrophage infiltration, and malondialdehyde levels in the liver. In line, this herbicide modulated immune response- (including Cd4, C8b, Cd28, Cxcr3, Cxcr6) and oxidative stress-related (such as Gsta1, Gsta2, Gsta4, Gstm1, Gstm2, Gstm3, Gstm4, Nqo1, Gpx2) genes in the hepatic transcriptome analysis. This exposure also enriched pro-inflammatory Deferribacteres phylum in fecal microbiome. In general, the herbicide mixtures did not feature the same effects attributed to 2,4-D isolated exposure. Our findings indicate that 2,4-D, at a dose within the toxicological limits, was able to induce disturbances in mainly at the liver and gut axes involved in NAFLD development in male mice.

Panx1 knockout promotes preneoplastic aberrant crypt foci development in a chemically induced model of mouse colon carcinogenesis

Colorectal cancer, which is the third leading cause of cancer-related deaths worldwide, is a multistep disease, featuring preneoplastic aberrant crypt foci (ACF) as the early morphological manifestation. The roles of hemichannel-forming transmembrane Pannexin 1 (Panx1) protein have not been investigated in the context of colon carcinogenesis yet, although it has contrasting roles in other cancer types. Thus, this study was conducted to examine the effects of Panx1 knockout (Panx1-/- ) on the early events of chemically induced colon carcinogenesis in mouse. Wild type (WT) and Panx1-/- female C57BL6J mice were submitted to a chemically induced model of colon carcinogenesis by receiving six intraperitoneal administrations of 1,2-dimethylhydrazine (DMH) carcinogen. Animals were euthanized 8 h (week 7) or 30 weeks (week 37) after the last DMH administration in order to evaluate sub-acute colon toxicity outcomes or the burden of ACF, respectively. At week 7, Panx1 genetic ablation increased DMH-induced genotoxicity in peripheral blood cells, malondialdehyde levels in the colon, and apoptosis (cleaved caspase-3) in colonic crypts. Of note, at week 37, Panx1-/- animals showed an increase in aberrant crypts (AC), ACF mean number, and ACF multiplicity (AC per ACF) by 56%, 57% and 20%, respectively. In essence, our findings indicate that Panx1 genetic ablation promotes preneoplastic ACF development during chemically induced mouse colon carcinogenesis, and a protective role of Panx1 is postulated.

Effects of glyphosate exposure on western diet-induced non-alcoholic fatty liver disease in mice

We evaluated whether glyphosate promotes western diet (WD)-induced non-alcoholic fatty liver disease (NAFLD). Male C57BL/6J mice were fed WD and received intragastrical glyphosate (0.05, 5 or 50 mg/kg) for 6 months. Glyphosate did not promote WD-induced obesity, hypercholesterolemia, glucose intolerance, hepatic steatosis, and fibrosis. Nonetheless, the higher dose (50 mg) enhanced hepatic CD68+ macrophage density, p65, TNF-α, and IL-6 protein levels. Furthermore, this dose decreased hepatic Nrf2 levels, while enhancing lipid peroxidation in the liver and adipose tissue. Hepatic transcriptome revealed that glyphosate at 50 mg upregulated 212 genes and downregulated 731 genes. Genes associated with oxidative stress and inflammation were upregulated, while key cell cycle-related genes were downregulated. Our results indicate that glyphosate exposure - in a dose within the toxicological limits - impairs hepatic inflammation/redox dynamics in a NAFLD microenvironment.

Integrated transcriptome and proteome analysis indicates potential biomarkers of prostate cancer in offspring of pregnant rats exposed to a phthalate mixture during gestation and lactation

As the second leading cause of death for cancer among men worldwide, prostate cancer (PCa) prevention and detection remain a critical challenge. One aspect of PCa research is the identification of common environmental agents that may increase the risk of initiation and progression of PCa. Endocrine disrupting chemicals (EDCs) are strong candidates for risk factors, partially because they alter essential pathways for prostate gland development and oncogenesis. Phthalates correspond to a set of commercially used plasticizers that humans are exposed to ubiquitously. Here, we show that maternal exposure to a phthalate mixture interferes with the expression profile of mRNA and proteins in the ventral prostate of offspring and increases the susceptibility to prostate adenocarcinomas in aged animals. The data highlight Ubxn11, Aldoc, Kif5c, Tubb4a, Tubb3, Tubb2, Rab6b and Rab3b as differentially expressed targets in young and adult offspring descendants (PND22 and PND120). These phthalate-induced targets were enriched for pathways such as: dysregulation in post-translational protein modification (PTPM), cell homeostasis, HSP90 chaperone activity, gap junctions, and kinases. In addition, the Kif5c, Tubb3, Tubb2b and Tubb4a targets were enriched for impairment in cell cycle and GTPase activity. Furthermore, these targets showed strong relationships with 12 transcriptional factors (TF), which regulate the phosphorylation of eight protein kinases. The correlation of TF-kinases is associated with alterations in immune system, RAS/ErbB/VEGF/estrogen/HIF-1 signaling pathways, cellular senescence, cell cycle, autophagy, and apoptosis. Downregulation of KIF5C, TUBB3 and RAB6B targets is associated with poor prognosis in patients diagnosed with adenocarcinoma. Collectively, this integrative investigation establishes the post-transcriptional mechanisms in the prostate that are modulated by maternal exposure to phthalate mixture during gestation and lactation.

Past, present, and future of chemically induced hepatocarcinogenesis rodent models: Perspectives concerning classic and new cancer hallmarks

Hepatocellular carcinoma (HCC), the main primary liver cancer, accounts for 5 % of all incident cases and 8.4 % of all cancer-related deaths worldwide. HCC displays a spectrum of environmental risk factors (viral chronic infections, aflatoxin exposure, alcoholic- and nonalcoholic fatty liver diseases) that result in molecular complexity and heterogeneity, contributing to a rising epidemiological burden, poor prognosis, and non-satisfactory treatment options. The emergence of HCC (i.e., hepatocarcinogenesis) is a multistep and complex process that addresses many (epi)genetic alterations and phenotypic traits, the so-called cancer hallmarks. "Polymorphic microbiomes", "epigenetic reprogramming", "senescent cells" and "unlocking phenotypic plasticity" are trending hallmarks/enabling features in cancer biology. As the main molecular drivers of HCC are still undruggable, chemically induced in vivo models of hepatocarcinogenesis are useful tools in preclinical research. Thus, this narrative review aimed at recapitulating the basic features of chemically induced rodent models of hepatocarcinogenesis, eliciting their permanent translational value regarding the "classic" and the "new" cancer hallmarks/enabling features. We gathered state-of-art preclinical evidence on non-cirrhotic, inflammation-, alcoholic liver disease- and nonalcoholic fatty liver-associated HCC models, demonstrating that these bioassays indeed express the recently added hallmarks, as well as reflect the interplay between classical and new cancer traits. Our review demonstrated that these protocols remain valuable for translational preclinical application, as they recapitulate trending features of cancer science. Further "omics-based" approaches are warranted while multimodel investigations are encouraged in order to avoid "model-biased" responses.

2,4-dichlorophenoxyacetic acid (2,4-D) exposure during postnatal development alters the effects of western diet on mouse prostate

Western diet (WD), abundant in saturated fats and simple carbohydrates, has been associated with the development of prostate diseases. In addition, 2,4-dichlorophenoxyacetic acid (2,4-D), an herbicide used in agricultural and non-agricultural settings, may interfere with the endocrine system impacting reproductive health. The association of both factors is something common in everyday life, however, there are no relevant studies associating them as possible modulators of prostatic diseases. This study evaluated the action of the herbicide 2,4-D on the postnatal development of the prostate in mice fed with WD. Male C57Bl/6J mice received simultaneously a WD and 2,4-D at doses of 0.02, 2.0, or 20.0 mg/kg b.w./day for 6 months. The prolongated WD intake induced obesity and glucose intolerance, increasing body weight and fat. WD induced morphological changes and increased PCNA-positive epithelial cells in prostate. Additionally, the WD increased gene expression of AR, antioxidant targets, inflammation-related cytokines, cell repair and turnover, and targets related to methylation and miRNAs biosynthesis compared to the counterpart (basal diet). 2,4-D (0.02 and 2.0) changed prostate morphology and gene expression evoked by WD. In contrast, the WD group exposed to 20 mg/kg of 2,4-D reduced feed intake and body weight, and increased expression of androgen receptor and genes related to cell repair and DNA methylation compared to the negative control. Our results showed that 2,4-D was able to modulate the effects caused by WD, mainly at lower doses. However, further studies are needed to elucidate the mechanisms of 2,4-D on the obesogenic environment caused by the WD.

Safety of lactational exposure to venlafaxine on the rat mammary gland development and carcinogenesis in F1 female offspring

The chronic use of selective serotonin reuptake inhibitors or serotonin-norepinephrine reuptake inhibitors (SNRIs) may result in human gynecomastia, mammoplasia, galactorrhea, and elevated breast cancer risk. As antidepressants are frequently used for postpartum depression (PPD) treatment, this study investigated the adverse effects of lactational exposure to venlafaxine (VENL, a selective SNRI) on mammary gland development and carcinogenesis in F1 female offspring. Thus, lactating Wistar rats (F0) received VENL by oral gavage at daily doses of 3.85, 7.7, or 15.4 mg/kg (N = 9, each group) from lactational day (LD 1) until the weaning of the offspring (LD 21). F1 female offspring were euthanized for mammary gland, and ovary histological analyses on the post-natal day (PND) 22 and 30 (1 pup/litter/period, N = 9, each group). At PND 22, other females (2 pups/litter, N = 18, each group) received a single dose of carcinogen N-methyl-N-nitrosourea (MNU, 50 mg/kg) intraperitoneally (i.p.) for tumor susceptibility assay until PND 250. Tumor incidence and latency were recorded and representative tumor samples were collected for histopathology. The results indicate that lactational exposure to VENL did not alter the development of the mammary gland (epithelial ductal tree or the mean number of terminal end buds), or the ovary (weight and primary, secondary, tertiary, and Graafian follicles) in prepubertal F1 female offspring. In addition, VENL exposure did not influence tumor incidence or tumor latency in adult female offspring that received MNU. Thus, the findings of this animal study indicated that lactational VENL exposure, a period similar to human PPD, did not exert an adverse effect on the mammary gland development at the prepubertal phase or on chemically induced mammary tumorigenesis in adult F1 female rats.

Assessment of the impact of glyphosate and 2,4-D herbicides on the kidney injury and transcriptome changes in obese mice fed a Western diet

The development of chronic kidney disease has been associated with comorbidities resulting from the consumption of Westernized dietary (WD) patterns, including obesity and other metabolic dysfunctions. Kidneys also have a crucial role in the metabolism and excretion of xenobiotics, including herbicides. There is limited knowledge regarding the simultaneous exposure to WD and glyphosate (glypho) and 2,4-D, the most used herbicides globally. Thus, this study examined whether exposure to glypho and/or 2,4-D, either individually or in mixed, could impact the early effects of WD intake on kidney histology and gene expression in a rodent model. Male C57BL6J mice were fed a WD containing 20% lard, 0.2% cholesterol, 20% sucrose, and high sugar solution with 23.1 and 18.9 g/L of D-fructose and D-glucose for six months. During this period, the mice also received glypho (0.05 or 5 mg/kg/day), 2,4-D (0.02 or 2 mg/kg/day), or a mixture of both (0.05 +0.02, 5 +2 mg/kg/day) via intragastric administration five times per week. The doses were within or below the established regulatory limits. While single or mixed exposures did not alter WD-induced obesity, tubular lipid vacuolation, or increased serum creatinine levels; the exposure to higher doses of the mixture (5 +2) reduced the mesangial matrix area and tubular cell proliferation, while increasing the density of F4/80 macrophages in the renal interstitium. In terms of transcriptomic analysis, the herbicide mixture altered the expression of 415 genes in the kidney, which were found to be associated with immune response processes, particularly those related to phagocyte activity. While discrete, findings indicate that herbicide mixtures, rather than single exposures, might induce minor deleterious effects on the kidneys of obese mice under WD intake.

Protective Effects of Omega-3 Supplementation against Doxorubicin-Induced Deleterious Effects on the Liver and Kidneys of Rats

Anthracycline doxorubicin (DOX) is still widely used as a chemotherapeutic drug for some solid tumors. Although DOX is highly effective, its side effects are limiting factors, such as cardio, nephro and hepatotoxicity. As such, approaches used to mitigate these adverse effects are highly encouraged. Omega 3 (ω-3), which is a class of long-chain polyunsaturated fatty acids, has been shown to have anti-inflammatory and antioxidant effects in preclinical bioassays. Thus, we evaluated the protective effects of ω-3 supplementation on hepatotoxicity and nephrotoxicity induced by multiple DOX administrations in rodents. Male Wistar rats (10 rats/group) were treated daily with ω-3 (400 mg/kg/day) by gavage for six weeks. Two weeks after the first ω-3 administration, the rats received DOX (3.5 mg/kg, intraperitoneal, 1×/week) for four weeks. DOX treatment reduced body weight gain increased systemic genotoxicity and caused liver-related (increase in serum ALT levels, thickness of the Glisson’s capsule, compensatory proliferation and p65 levels) and kidney-related (increase in serum urea and creatinine levels, and incidence of tubular dilatation) deleterious outcomes. In contrast, ω-3 supplementation was safe and abrogated the DOX-related enhancement of systemic genotoxicity, serum urea and creatinine levels. Furthermore, ω-3 intervention reduced by 50% the incidence of kidney histological lesions while reducing by 40–50% the p65 protein level, and the proliferative response in the liver induced by DOX. Our findings indicate that ω-3 intervention attenuated the DOX-induced deleterious effects in the liver and kidney. Therefore, our findings may inspire future mechanistical investigations and clinical interventions with ω-3 on the reported outcomes.

Dietary Capsaicin Reduces Chemically Induced Rat Urinary Bladder Carcinogenesis

Capsaicin (CAP) is the compound responsible for pungency in chili peppers, presenting several biological properties. But its general safety and effectiveness in the context of carcinogenesis has not been fully clarified. Thus, the present study evaluated whether dietary CAP modifies the development of urothelial lesions induced by the carcinogen N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in male Sprague-Dawley rats. Animals were randomly allocated into 6 groups: G1 - treated with 0.05% BBN in drinking water (weeks 1-12) and received a balanced diet (weeks 1-20); G2 and G3-treated with BBN (weeks 1-12) and received a balanced diet with 0.01 or 0.02% CAP (weeks 1-20), respectively; G4 and G5- only received a balanced diet with 0.01 or 0.02% CAP (weeks 1-20), respectively; G6 - only received a balanced diet (weeks 1-20). At the end of week 20, the incidence and types of urothelial lesions, proliferating cell nuclear antigen (PCNA) labeling index, and matrix metalloproteinases (MMP) 2 and 9 activities were analyzed. A significant reduction was observed in the incidence and multiplicity of simple (p = 0.020 and p = 0.011) and nodular/papillary (p = 0.030 and p = 0.003) hyperplasias and papillomas/carcinomas (p = 0.023 and p = 0.020), epithelial proliferation (p = 0.007) and in the activity of the intermediate form of MMP-2 (p < 0.001) and pro-MMP-9 activities (p < 0.002), in BBN + 0.02% CAP (G3) group in comparison to BBN (G1) group. Capsaicin intake per se did not alter body weight, liver and kidney weights, urothelial histology or serum biochemical parameters. Thus, dietary CAP was safe and showed a protective effect against rat BBN-induced urothelial carcinogenesis.

The Implications of Connexin 43 Deficiency during the Early Stages of Chemically Induced Mouse Colon Carcinogenesis

Colorectal cancer (CRC), associated with an increased intake of processed red meats, saturated fats, and simple carbohydrates accompanied by low dietary fiber, fruits, and vegetables consumption, presents a high epidemiological burden. Connexin43 (Cx43) protein, which forms gap junctions or hemichannels, has tumor suppressor or oncogenic activities in a cancer type- and stage-dependent manner. Cx43 expression varies during colon carcinogenesis, and its functional role is not fully understood. Thus, we evaluated the implications of Cx43 heterologous deletion (Cx43^+/-) during the early stages of a chemically induced model of colon carcinogenesis. Female C57BL/6J mice (wild-type or Cx43^+/-) were submitted to a colon carcinogenesis model induced by 1,2 dimethylhydrazine (DMH). Mice were euthanized eight hours (week 7) or 30 weeks (week 37) after the last DMH administration to evaluate subacute colon toxicity outcomes or the burden of (pre)neoplastic lesions, respectively. At week 7, Cx43 deficiency inferred no alterations in the DMH-induced increase in systemic (peripheral blood), in situ (colonocytes) DNA damage, and apoptosis in the colonocytes. At week 30, Cx43^+/- mice presented an increase in preneoplastic aberrant crypt foci (ACF) multiplicity, while no alterations were observed in colorectal adenoma (CRA) occurrence, multiplicity, volume, proliferation, growth, and β-catenin immunoexpression. Similarly, an in silico analysis of human CRA showed decreased mRNA expression of Cx43 with no correlation with proliferation, apoptosis, and β-catenin markers. These findings indicate the discrete role of Cx43 in the early stages of chemically induced mouse colon carcinogenesis.

Are isothiocyanates and polyphenols from Brassicaceae vegetables emerging as preventive/therapeutic strategies for NAFLD? The landscape of recent preclinical findings

Nonalcoholic fatty liver disease (NAFLD) is a lipid impairment-related chronic metabolic disease that affects almost 25% of the worldwide population and has become the leading cause of liver transplantation in the United States of America (USA). NAFLD may progress from simple hepatic steatosis (HS) to nonalcoholic steatohepatitis (NASH), which occurs simultaneously in an inflammatory and fibrotic microenvironment and affects approximately 5% of the global population. Recently, NASH has been suggested to be a relevant driver in progressive liver cirrhosis and a population-attributable factor in hepatocellular carcinoma patients. Moreover, predictions show that NAFLD-related annual health costs in the USA have reached ∼$100 bi., but effective therapies are still scarce. Thus, new preventative strategies for this hepatic disease urgently need to be developed. The Brassicaceae vegetable family includes almost 350 genera and 3500 species and these are one of the main types of vegetables harvested and produced worldwide. These vegetables are well-known sources of glucobrassicin-derivative molecules, such as isothiocyanates and phenolic compounds, which have shown antioxidant and antilipogenic effects in preclinical NAFLD data. In this review, we gathered prominent evidence of the in vivo and in vitro effects of these vegetable-derived nutraceutical compounds on the gut-liver-adipose axis, which is a well-known regulator of NAFLD and may represent a new strategy for disease control.

Caffeine and Chlorogenic Acid Combination Attenuate Early-Stage Chemically Induced Colon Carcinogenesis in Mice: Involvement of oncomiR miR-21a-5p

Colorectal cancer (CRC) is one of most common cancers worldwide, with high rates of mortality. Epidemiological findings demonstrate that coffee consumption reduces the risk of developing CRC by ~13%. In general, in vivo and in vitro findings demonstrate the antiproliferative, antioxidant and proapoptotic effects of brewed coffee or major bioavailable coffee compounds. Thus, it was assessed whether caffeine (CAF) and/or chlorogenic acid (CGA) attenuates the early-stage of chemically induced mouse colon carcinogenesis. Male Swiss mice were submitted to a 1,2-dimethylhydrazine/deoxycholic acid (DMH/DCA)-induced colon carcinogenesis model. These animals received CAF (50 mg/kg), CGA (25 mg/kg) or CAF+CGA (50 + 25 mg/kg) intragastrically for five times/week for ten weeks. CAF+CGA had the most pronounced effects on decreasing epithelial cell proliferation (Ki-67) and increasing apoptosis (cleaved caspase-3) in colonic crypts. This treatment also decreased the levels of proinflammatory cytokines IL-6, IL-17 and TNF-α, and downregulated the oncomiR miR-21a-5p in the colon. Accordingly, the analysis of miR-21a-5p targets demonstrated the genes involved in the negative regulation of proliferation and inflammation, and the positive regulation of apoptosis. Ultimately, CAF+CGA attenuated preneoplastic aberrant crypt foci (ACF) development. Our findings suggest that a combination of coffee compounds reduces early-stage colon carcinogenesis by the modulation of miR-21a-5p expression, highlighting the importance of coffee intake to prevent CRC.

In Vivo and In Vitro Models of Hepatocellular Carcinoma: Current Strategies for Translational Modeling

Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide and the third leading cause of cancer-related death globally. HCC is a complex multistep disease and usually emerges in the setting of chronic liver diseases. The molecular pathogenesis of HCC varies according to the etiology, mainly caused by chronic hepatitis B and C virus infections, chronic alcohol consumption, aflatoxin-contaminated food, and non-alcoholic fatty liver disease associated with metabolic syndrome or diabetes mellitus. The establishment of HCC models has become essential for both basic and translational research to improve our understanding of the pathophysiology and unravel new molecular drivers of this disease. The ideal model should recapitulate key events observed during hepatocarcinogenesis and HCC progression in view of establishing effective diagnostic and therapeutic strategies to be translated into clinical practice. Despite considerable efforts currently devoted to liver cancer research, only a few anti-HCC drugs are available, and patient prognosis and survival are still poor. The present paper provides a state-of-the-art overview of in vivo and in vitro models used for translational modeling of HCC with a specific focus on their key molecular hallmarks.

Modifying effects of menthol against benzo(a)pyrene-induced forestomach carcinogenesis in female Swiss mice

Benzo(a)pyrene (BaP) is a polycyclic aromatic hydrocarbon widespread in the environment and closely associated to tobacco use, which is an important risk factor for highly incident stomach cancer. Menthol, a monoterpene extracted from Mentha genus species, has multiple biological properties, including anti-inflammatory and gastroprotective properties, but its effects on carcinogenesis are still to be fully understood. Thus, we evaluated the modifying effects of Ment against BaP-induced forestomach carcinogenesis. Female Swiss mice received BaP by intragastrical (i.g.) administration (50 mg/kg of body weight [b wt], 2×/week), from weeks 1-5 weeks. Concomitantly, mice received Menthol at 25 (Ment25) or 50 (Ment50) mg/kg b wt (i.g, 3×/week). Animals were euthanized at weeks 5 (n = 5 mice/group) or 30 (n = 10 mice/group). At week 5, both Ment doses reduced peripheral leukocyte blood genotoxicity 4 h after the last BaP administration, but only Ment50 attenuated this biomarker 8 h after the last BaP administration. In accordance to these findings, both Ment interventions attenuated BaP-induced increase in the percentage of H2A.X-positive forestomach epithelial cells. Moreover, Ment50 reduced cell proliferation and apoptosis (i.e., Ki-67 and caspase-3, respectively) in forestomach epithelium but exerted no significant effects on NFκB, and Nrf2 protein levels. At week 30, Ment50 reduced by ~55% the incidence of BaP-induced forestomach diffuse hyperplasia and multiplicity of forestomach tumors (squamous cell papillomas and carcinomas). Our findings indicate that Ment50, administered during initiation phase, attenuates forestomach carcinogenesis by reducing early genotoxicity, cell proliferation, and apoptosis induced by BaP.

Synbiotic supplementation attenuates the promoting effect of indole-3-carbinol on colon tumorigenesis

Indole-3 carbinol (I3C) has shown dual effects on the promotion and progression stages of colon carcinogenesis while synbiotics (Syn) have exerted anti-carcinogenic activities in most rodent studies. This study aimed to investigate the effects of I3C given alone or together with a Syn intervention on 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis. All animals were given four subcutaneous DMH injections (4×40 mg/kg bodyweight, twice a week for two weeks) and then received either basal diet (G1), basal diet containing I3C (1g/kg chow) (G2) or basal diet containing I3C+Syn (I3C + inulin 50g/kg chow + Bifidobacterium lactis BB-12^®), 2.5×10¹⁰ cfu/g of basal diet), (G3) for 21 weeks. Dietary I3C (G2) significantly increased tumour volume and cell proliferation when compared to the DMH control group (G1). Syn intervention (G3) significantly reduced tumour volume and cell proliferation when compared to I3C (G2). The colon tumours found were classified into well-differentiated tubular adenomas or adenocarcinomas. Dietary I3C or I3C+Syn did not significantly affect the incidence and the multiplicity of tumours in comparison with the DMH control group. Furthermore, Syn intervention (G3) increased Gstm1 and reduced Mapk9 gene expression in colonic tumours. The findings of the present study show that the dietary I3C shows a weak promoting activity, while the combination with Syn ameliorates I3C effects.

Capsaicin lacks tumor-promoting effects during colon carcinogenesis in a rat model induced by 1,2-dimethylhydrazine

Capsaicin (CPS, 8-methyl-N-vanillyl-trans-6-nonenamide), a pungent alkaloid from chili peppers, has contradictory effects in both experimental and human carcinogenesis. Thus, we evaluated the modifying effects of chronic CPS during the promotion and progression stages of rat colon carcinogenesis induced by 1,2-dimethylhydrazine (DMH). Male Wistar rats were given four subcutaneous injections of DMH (40 mg/body weight (b.w.)) twice a week, for 2 weeks. After DMH-induced tumor initiation, the animals were treated with CPS at 5 or 50 mg/kg b.w. by gavage for 24 weeks (three times a week). High-dose CPS reduced both cell proliferation in adjacent "normal-appearing" colonic crypts and the total number of preneoplastic aberrant crypt foci (ACF) but did not change the number of dysplastic ACF or ACF multiplicity. Although the proportion of adenomas was increased, and tubular adenocarcinomas decreased in high-dose CPS, both CPS interventions exerted no effects on total tumor incidence, volume, multiplicity, cell proliferation (Ki-67), and apoptosis (caspase-3). In accordance, high-dose CPS treatment had discrete effects on gene expression in colon tumors, as only 3/94 (3.19%) genes were significantly modified (downregulation of Cebpd and Fasl, and upregulation of Jag1). The findings of the present study show that CPS does not impact on the promotion/progression stages of rat colon carcinogenesis. Therefore, CPS at a high-dose intervention showed to be a safe food ingredient.

Beneficial effects of anthocyanin-rich peels of Myrtaceae fruits on chemically-induced liver fibrosis and carcinogenesis in mice

Hepatocellular carcinoma (HCC) arising from fibrosis/cirrhosis is the most common type of primary liver cancer. Conversely, a higher intake of fruits and vegetables might play a protective role in HCC risk. Recently, Myrtaceae family tropical fruits have raised great interest due to the high levels of anthocyanins especially in their peels, which are usually discarded upon consumption. Anthocyanins are antioxidant pigments known to have beneficial effects in vivo/in vitro cancer bioassays. Thus, we evaluated whether dietary Myrciaria jaboticaba, Syzygium cumini, and Syzygium malaccense fruit peel powders reduce fibrosis and hepatocarcinogenesis in mice. Female C3H/HeJ mice were submitted to the model of diethylnitrosamine/carbon tetrachloride-induced liver fibrosis and carcinogenesis. Concomitantly, mice received a basal diet containing 2% of M. jaboticaba, S. cumini, or S. malaccense fruit peel powders, obtained by convective drying, for 10 weeks. M. jaboticaba peel powder showed the highest levels of total anthocyanins, while S. cumini peel powder displayed the greatest diversity of these pigments. All Myrtaceae family peel powders reduced the serum levels of the liver injury marker alanine aminotransferase. M. jaboticaba peel feeding reduced the incidence of liver preneoplastic foci, hepatocyte proliferation (Ki-67), and the protein levels of hepato-mitogen tumor necrosis factor-alpha (TNF-α). M. jaboticaba peel feeding also diminished liver lipid peroxidation and increased total glutathione levels. S. cumini peel feeding reduced hepatic collagen, lipid peroxidation, and TNF-α levels while increased catalase activity. Although S. malaccense peel powder, which displayed the lowest anthocyanin levels, decreased oxidative stress, and cytokine levels, no effects were observed on liver fibrosis or preneoplastic lesion outcomes. Findings indicate a protective effect of anthocyanin-rich M. jaboticaba and S. cumini peel powder feeding on preneoplastic lesion development and fibrosis, respectively. Results indicate that differential biological responses may be attributed to distinct anthocyanin profiles and levels, assigning a functional/market value to the underutilized peel fraction.

The combination of coffee compounds attenuates early fibrosis-associated hepatocarcinogenesis in mice: involvement of miRNA profile modulation

Aberrant microRNA expression implicates on hepatocellular carcinoma (HCC) development. Conversely, coffee consumption reduces by ~40% the risk for fibrosis/cirrhosis and HCC, while decaffeinated coffee does not. It is currently unknown whether these protective effects are related to caffeine (CAF), or to its combination with other common and/or highly bioavailable coffee compounds, such as trigonelline (TRI) and chlorogenic acid (CGA). We evaluated whether CAF individually or combined with TRI and/or CGA alleviates fibrosis-associated hepatocarcinogenesis, examining the involvement of miRNA profile modulation. Then, male C3H/HeJ mice were submitted to a diethylnitrosamine/carbon tetrachloride-induced model. Animals received CAF (50 mg/kg), CAF+TRI (50 and 25 mg/kg), CAF+CGA (50 and 25 mg/kg) or CAF+TRI+CGA (50, 25 and 25 mg/kg), intragastrically, 5×/week, for 10 weeks. Only CAF+TRI+CGA combination reduced the incidence, number and proliferation (Ki-67) of hepatocellular preneoplastic foci while enhanced apoptosis (cleaved caspase-3) in adjacent parenchyma. CAF+TRI+CGA treatment also decreased hepatic oxidative stress and enhanced the antioxidant Nrf2 axis. CAF+TRI+CGA had the most pronounced effects on decreasing hepatic pro-inflammatory IL-17 and NFκB, contributing to reduce CD68-positive macrophage number, stellate cell activation, and collagen deposition. In agreement, CAF+TRI+CGA upregulated tumor suppressors miR-144-3p, miR-376a-3p and antifibrotic miR-15b-5p, frequently deregulated in human HCC. CAF+TRI+CGA reduced the hepatic protein levels of pro-proliferative EGFR (miR-144-3p target), antiapoptotic Bcl-2 family members (miR-15b-5p targets), and the number of PCNA (miR-376a-3p target) positive hepatocytes in preneoplastic foci. Our results suggest that the combination of most common and highly bioavailable coffee compounds, rather than CAF individually, attenuates fibrosis-associated hepatocarcinogenesis by modulating miRNA expression profile.

Protective Effects of Dietary Capsaicin on the Initiation Step of a Two-Stage Hepatocarcinogenesis Rat Model

Capsaicin (CPS), an ingredient of Capsicum plants, has anti-inflammatory, antioxidant and antitumoral properties. The mechanisms of CPS on hepatocarcinogenesis preclinical bioassays are not described. Thus, the protective effects CPS were evaluated in the early stages of chemically-induced hepatocarcinogenesis. Male Wistar rats received diet containing 0.01% or 0.02% CPS for 3 weeks. Afterwards, animals received a dose of hepatocarcinogen diethylnitrosamine (DEN, 100 mg/kg body weight). From weeks 4-12, groups had their diet replaced by a 0.05% phenobarbital supplemented one to promote DEN-induced preneoplastic lesions. Animals were euthanized 24 h after DEN administration (n = 5/group) or at week 12 (n = 9/group). The estimated CPS intake in rats resembled human consumption. At the end of week 3, dietary 0.02% CPS attenuated DEN-induced oxidative damage and, consequently, hepatocyte necrosis by reducing serum alanine aminotransferase levels, liver CD68-positive macrophages, lipid peroxidation, while increasing antioxidant glutathione system. Additionally, 0.02% CPS upregulated vanilloid Trpv1 receptor and anti-inflammatory epoxygenase Cyp2j4 genes in the liver. Ultimately, previous 0.02% CPS intake decreased the number of GST-P-positive preneoplastic lesions at week 12. Thus, CPS attenuated preneoplastic lesion development, primarily by diminishing DEN-induced oxidative liver injury. Findings indicate that CPS is a promising chemopreventive agent when administered after and during the early stages of hepatocarcinogenesis.

Early molecular events associated with liver and colon sub-acute responses to 1,2-dimethylhydrazine: Potential implications on preneoplastic and neoplastic lesion development

This study unveiled the early cellular and molecular events induced by 1,2-dimethylhydrazine (DMH) in the colon and liver and their implications on pre- and neoplastic lesion burden in a late timepoint. Male Wistar rats received four DMH injections (40 mg/kg body weight) for 2 weeks and were sacrificed 24 h (short-term study) or 22 (medium-term study) weeks after the last DMH administration. In the short-term study, DMH led to increased leukocyte (comet assay) and colon (H2AX) genotoxicity, enhanced proliferation (Ki-67) and apoptosis (caspase-3) indexes in both liver and colon. Furthermore, the expression of mRNA (Cat, Gsta1, Gsta2, Gpx1, Gstm1, Sod1, Sod2 and Sod3) and the activity of antioxidant agents were diminished in the colon and liver of DMH-induced rats, eliciting an environment of oxidative stress featuring elevated lipid hydroperoxide levels. Apoptosis effectors were upregulated in the liver (Bax, Casp3 and Fas), and developmental genes were downregulated in both colon and liver (Foxa1, Foxa2, Smad2 and Smad4). In the medium-term study, DMH led to a high number of preneoplastic colonic aberrant crypt foci and tumors (adenomas and invasive adenocarcinomas) but few preneoplastic hepatic glutathione S-transferase (GST-P)-positive foci. Our novel gene expression data highlights overlooked mechanisms in the liver (main metabolizing organ) and colon (main target organ) on toxicity and carcinogenesis induced by repeated doses of DMH, as both organs should be considered in further interventions on the initiation stage of colon carcinogenesis.

Fibrosis-associated hepatocarcinogenesis revisited: Establishing standard medium-term chemically-induced male and female models

Hepatocellular carcinoma causes ~10% of all cancer-related deaths worldwide, usually emerging in a background of liver fibrosis/cirrhosis (70%-90% of cases). Chemically-induced mouse models for fibrosis-associated hepatocarcinogenesis are widely-applied, resembling the corresponding human disease. Nonetheless, a long time is necessary for the development of preneoplastic/neoplastic lesions. Thus, we proposed an early fibrosis-associated hepatocarcinogenesis model for male and female mice separately, focusing on reducing the experimental time for preneoplastic/neoplastic lesions development and establishing standard models for both sexes. Then, two-week old susceptible C3H/HeJ male and female mice (n = 8 animals/sex/group) received a single dose of diethylnitrosamine (DEN, 10 or 50 mg/Kg). During 2 months, mice received 3 weekly doses of carbon tetrachloride (CCl4, 10% corn oil solution, 0.25 to 1.50 μL/g b.wt.) and they were euthanized at week 17. DEN/CCl4 protocols for males and females displayed clear liver fibrosis, featuring collagen accumulation and hepatic stellate cell activation (α-SMA). In addition, liver from males displayed increased CD68+ macrophage number, COX-2 protein expression and IL-6 levels. The DEN/CCl4 models in both sexes impaired antioxidant defense as well as enhanced hepatocyte proliferation and apoptosis. Moreover, DEN/CCl4-treated male and female developed multiple preneoplastic altered hepatocyte foci and hepatocellular adenomas. As expected, the models showed clear male bias. Therefore, we established standard and suitable fibrosis-associated hepatocarcinogenesis models for male and female mice, shortening the experimental time for the development of hepatocellular preneoplastic/neoplastic lesions in comparison to other classical models.

An integrative analysis of chemically-induced cirrhosis-associated hepatocarcinogenesis: Histological, biochemical and molecular features

This study aimed the integrative characterization of morphological, biochemical and molecular features of chemically-induced cirrhosis-associated hepatocarcinogenesis. Thus, male Wistar rats were submitted to a diethylnitrosamine (DEN)/thioacetamide (TAA)-induced model. Liver tissue was processed for global gene expression, histopathological and collagen evaluations; as well as immunohistochemical and oxidative stress analysis. Gene Ontology and functional analysis showed the upregulation of extracellular matrix deposition genes, such as collagen type I alpha 1 and 2 (Col1α1 and Col1α2) and tissue inhibitor of metalloproteinase 1 and 2 genes (Timp1 and Timp2). In agreement these findings, animals presented extensive liver cirrhosis with increased collagen deposition (Sirius red). Besides, the animals developed many glutathione S-transferase pi (GST-P)-positive preneoplastic lesions showing high cell proliferation (Ki-67), in keeping with the Gstp1 and Gstp2 increased gene expression. DEN/TAA-treated rats also showed the upregulation of tumorigenesis-related annexin A2 gene (Anxa2) and few neoplastic lesions (hepatocellular adenomas, carcinomas, and cholangiocarcinoma). In contrast, gene expression and activity of antioxidant enzymes were decreased (glutathione peroxidase, total glutathione-S-transferase, and catalase). The model featured remarkable similarities to human hepatocarcinogenesis. Our findings could bring up new molecular insights into cirrhosis-associated hepatocarcinogenesis, and provide a suitable animal model for the establishment of further diagnostic, preventive and therapeutic approaches.

Diuron Lacks Promoting Potential in a Rat Liver Bioassay

The promoting activity of the herbicide Diuron was evaluated in a medium-term rat liver carcinogenesis bioassay that uses as endpoint immunohistochemically identified glutathione S-transferase positive (GST-P+) foci. Male Wistar rats were allocated to the following groups: G1 to G6 were initiated for liver carcinogenesis by a single dose of diethylnitrosamine (DEN, 200 mg/kg) while groups G7 and G8 received only 0.9% NaCl (DEN vehicle). From the 2nd week animals were fed a basal diet (G1 and G7) or a diet added with Diuron at 125, 500, 1250, 2500 and 2500 ppm (G2 to G5 and G8, respectively) or 200 ppm Hexaclorobenzene (HCB; G6). The animals were submitted to 70% partial hepatectomy at the 3rd week and sacrificed at the 8th week. The herbicide did not alter ALT or creatinine serum levels. No conspicuous GST-P+ foci development was registered in non-initiated rats fed Diuron at 2500 ppm. While DEN-initiated animals fed Diuron at 1250 or 2500 ppm developed mild centrilobular hypertrophy, DEN-initiated HCB-fed animals showed severe liver centrilobular hypertrophy and significant GST-P+ foci development. These findings indicate that the medium-term assay adopted in this study does not reveal any liver carcinogenesis initiating or promoting potential of Diuron in the rat.

Early Life and Postnatal Western Diet Feeding and Susceptibility to Chemically Induced Colonic Aberrant Crypt Foci in Male Rats Offspring

The modifying effects of a Western diet (WD) during early life on the susceptibility to colon carcinogenesis induced by dimethylhydrazine (DMH) were examined in male rats as later adults. Three groups were studied: a lifetime control diet-fed group, a test group fed WD since pregnancy from dams until postnatal day (PND) 42, and a group fed WD at adulthood. At PND 70, all groups received the carcinogen DMH and were euthanized 10 wk later. Colonic aberrant crypt foci (ACF) were scored (number and crypt multiplicity) and the altered pattern of β-catenin expression was evaluated in the colonic lesions. ACF multiplicity (≥4 crypts) was significantly higher in the group fed WD at early life than in the group fed the control diet. ACF number, crypt multiplicity, and the number of high-grade dysplastic lesions were significantly higher in the group fed WD at adulthood than in the groupfed the control diet. The number of lesions with altered β-catenin expression was higher in the groups receiving WD at early life or at adulthood than in the lifetime control-diet-fed group. These findings indicate that WD exposure at early life increased the susceptibility to colon carcinogenesis at adulthood.

Lipidomic fatty acid profile and global gene expression pattern in mammary gland of rats that were exposed to lard-based high fat diet during fetal and lactation periods associated to breast cancer risk in adulthood

The persistent effects of animal fat consumption during pregnancy and nursing on the programming of breast cancer risk among female offspring were studied here. We have previously found that female offspring of rat dams that consumed a lard-based high-fat (HF) diet (60% fat-derived energy) during pregnancy, or during pregnancy and lactation, were at a reduced risk of developing mammary cancer. To better understand the unexpected protective effects of early life lard exposure, we have applied lipidomics and nutrigenomics approaches to investigate the fatty acid profile and global gene expression patterns in the mammary tissue of the female offspring. Consumption of this HF diet during gestation had few effects on the mammary tissue fatty acids profile of young adult offspring, while exposure from gestation throughout nursing promoted significant alterations in the fatty acids profile. Major differences were related to decreases in saturated fatty acids (SFA) and increases in omega-6 polyunsaturated fatty acids (PUFAs), monounsaturated fatty acids (MUFAs) and conjugated linolenic acid (CLA) concentrations. In addition several differences in gene expression patterns by microarray analysis between the control and in utero or in utero and during lactation HF exposed offspring were identified. Differential dependency network (DDN) analysis indicated that many of the genes exhibited unique connections to other genes only in the HF offspring. These unique connections included Hrh1-Ythdf1 and Repin1-Elavl2 in the in utero HF offspring, and Rnf213-Htr3b and Klf5-Chrna4 in the in utero and lactation HF offspring, compared with the control offspring. We conclude that an exposure to a lard-based HF diet during early life changes the fatty acid profile and transcriptional network in mammary gland in young adult rats, and these changes appear to be consistent with reduced mammary cancer risk observed in our previous study.

Yacon (Smallanthus sonchifolius) and Lactobacillus acidophilus CRL 1014 reduce the early phases of colon carcinogenesis in male Wistar rats

The modifying effects of aqueous yacon extract (AYE) and Lactobacillus acidophilus CRL 1014 against colon carcinogenesis induced by 1,2-dimethylhydrazine (DMH) in male Wistar rats were investigated. Animals were allocated into five groups: G1: untreated group; G2: DMH-treated group; G3: DMH+L. acidophilus-treated group; G4: DMH+AYE-treated group; G5: DMH+L. acidophilus and AYE-treated group. A significant reduction (p<0.05) in leukocyte DNA damage and in colonic cell proliferation was observed after the first DMH administration in G3 (probiotic), G4 (prebiotic) and G5 (synbiotic) groups. In this moment, a significant increase (p<0.05) in colonic apoptosis was also observed in G3 (probiotic) and G5 (synbiotic) groups. In special, at five months after DMH administrations, a significant reduction (p<0.05) in ACF development was observed in G3 (probiotic), G4 (prebiotic) and G5 (synbiotic) groups. Incidence of colon tumors was lower at five months in G4 (prebiotic) and G5 (synbiotic) groups but not in eight months after DMH administrations. In conclusion, the findings suggest that the oral treatments have potential effects as a chemopreventive agent against colon carcinogenesis on an early stage of tumor development.

Effects of Ginkgo biloba on chemically-induced mammary tumors in rats receiving tamoxifen

Background

Ginkgo biloba extract (GbE) is used extensively by breast cancer patients undergoing treatment with Tamoxifen (TAM). Thus, the present study investigated the effects of GbE in female Sprague–Dawley (SD) rats bearing chemically-induced mammary tumors and receiving TAM.

Methods

Animals bearing mammary tumors (≥1 cm in diameter) were divided into four groups: TAM [10 mg/kg, intragastrically (i.g.)], TAM plus GbE [50 and 100 mg/kg, intraperitoneally (i.p.)] or an untreated control group. After 4 weeks, the therapeutic efficacy of the different treatments was evaluated by measuring the tumor volume (cm³) and the proportions of each tumor that were alive, necrotic or degenerative (mm²). In addition, labeling indexes (LI%) were calculated for cell proliferation (PCNA LI%) and apoptosis (cleaved caspase-3 LI%), expression of estrogen receptor-alpha (ER-α) and p63 biomarkers.

Results

Overall, the tumor volume and the PCNA LI% within live tumor areas were reduced by 83% and 99%, respectively, in all TAM-treated groups when compared to the untreated control group. GbE treatment (100 mg/kg) reduced the proportions of live (24.8%) and necrotic areas (2.9%) (p = 0.046 and p = 0.038, respectively) and significantly increased the proportion of degenerative areas (72.9%) (p = 0.004) in mammary tumors when compared to the group treated only with TAM. The expression of ER-α, p63 and cleaved caspase-3 in live tumor tissues was not modified by GbE treatment.

Conclusions

Co-treatment with 100 mg/kg GbE presented a slightly beneficial effect on the therapeutic efficacy of TAM in female SD rats bearing mammary tumors.

Macrophage activity and histopathology of the lymphohematopoietic organs in male Wistar rats orally exposed to single or mixed pesticides

The noxious effects of low or effective dose exposure to single or mixed pesticides on macrophage activity and the lymphohematopoietic organs were investigated. Male Wistar rats were orally exposed to dichlorvos, dicofol, endosulfan, dieldrin and permethrin, either as single or combined mixtures during a 28-day study containing eight groups: one group received a semipurified diet (non-treated); two groups received a semipurified diet containing low dose mixture (dieldrin 0.025 mg/kg, endosulfan, 0.6 mg/kg, dicofol 0.22 mg/kg, dichlorvos 0.23 mg/kg, permethrin 5 mg/kg) or an effective dose mixture (dichlorvos 2.3 mg/kg, dicofol 2.5 mg/kg, endosulfan 2.9 mg/kg, dieldrin 0.05 mg/kg and permethrin 25.0 mg/kg), respectively; the other five groups received a semipurified diet containing each single pesticide in effective doses. At sacrifice, the thymus, spleen, mesenteric lymph nodes, Payer's patches and bone marrow were removed for histological analysis. Peritoneal macrophages were obtained to determine the phagocytosis and spreading indexes and tumoral necrosis factor alpha (TNF-α), nitric oxide (NO) and H₂O₂ production. Exposure to pesticide mixtures did not alter the percentage of macrophage phagocytosis and spreading, TNF-α production or the NO and H₂O₂ release when compared to the non-treated group. Neither was there any apparent evidence that a pesticide mixture at low or effective doses altered the histological structure of the lymphohematopoietic organs. The findings indicate that short-term treatment with pesticide mixtures did not induce an apparent immunotoxic effect in male Wistar rats.

Evaluation of carcinogenic potential of diuron in a rat mammary two-stage carcinogenesis model

This study aimed to evaluate the carcinogenic potential of the herbicide Diuron in a two-stage rat medium-term mammary carcinogenesis model initiated by 7,12-dimethylbenz(a)anthracene (DMBA). Female seven-week-old Sprague-Dawley (SD) rats were allocated to six groups: groups G1 to G4 received intragastrically (i.g.) a single 50 mg/kg dose of DMBA; groups G5 and G6 received single administration of canola oil (vehicle of DMBA). Groups G1 and G5 received a basal diet, and groups G2, G3, G4, and G6 were fed the basal diet with the addition of Diuron at 250, 1250, 2500, and 2500 ppm, respectively. After twenty-five weeks, the animals were euthanized and mammary tumors were histologically confirmed and quantified. Tumor samples were also processed for immunohistochemical evaluation of the expressions of proliferating cell nuclear antigen (PCNA), cleaved caspase-3, estrogen receptor-α (ER-α), p63, bcl-2, and bak. Diuron treatment did not increase the incidence or multiplicity of mammary tumors (groups G2 to G4 versus Group G1). Also, exposure to Diuron did not alter tumor growth (cell proliferation and apoptosis indexes) or immunoreactivity to ER-α, p63 (myoephitelial marker), or bcl-2 and bak (apoptosis regulatory proteins). These findings indicate that Diuron does not have a promoting potential on mammary carcinogenesis in female SD rats initiated with DMBA.

Efficacy of geraniol but not of β-ionone or their combination for the chemoprevention of rat colon carcinogenesis

β-ionone (βI), a cyclic isoprenoid, and geraniol (GO), an acyclic monoterpene, represent a promising class of dietary chemopreventive agents against cancer, whose combination could result in synergistic anticarcinogenic effects. The chemopreventive activities of βI and GO were evaluated individually or in combination during colon carcinogenesis induced by dimethylhydrazine in 48 3-week-old male Wistar rats (12 per group) weighing 40-50 g. Animals were treated for 9 consecutive weeks with βI (16 mg/100 g body weight), GO (25 mg/100 g body weight), βI combined with GO or corn oil (control). Number of total aberrant crypt foci (ACF) and of ACF ≥4 crypts in the distal colon was significantly lower in the GO group (66 ± 13 and 9 ± 2, respectively) compared to control (102 ± 9 and 17 ± 3) and without differences in the βI (91 ± 11 and 14 ± 3) and βI+GO groups (96 ± 5 and 19 ± 2). Apoptosis level, identified by classical apoptosis morphological criteria, in the distal colon was significantly higher in the GO group (1.64 ± 0.06 apoptotic cells/mm²) compared to control (0.91 ± 0.07 apoptotic cells/mm²). The GO group presented a 0.7-fold reduction in Bcl-2 protein expression (Western blot) compared to control. Colonic mucosa concentrations of βI and GO (gas chromatography/mass spectrometry) were higher in the βI and GO groups, respectively, compared to the control and βI+GO groups. Therefore, GO, but not βI, represents a potential chemopreventive agent in colon carcinogenesis. Surprisingly, the combination of isoprenoids does not represent an efficient chemopreventive strategy.

Screening for in vitro and in vivo antitumor activities of the mushroom Agaricus blazei

We have investigated the in vitro antitumor activity of the mushroom Agaricus blazei Murill on human cancer cell lines as well as its potential anticancer activity in a model of rat colon carcinogenesis. The in vitro anticancer analysis was performed using 9 human cancer cell lines incubated with organic and aqueous extracts of A. blazei. Antitumor activity was observed with the dichloromethane/methanol and hexanic extracts of A. blazei at 250 mu g/ml for all cancer cell lines tested. No antiproliferative/cytotoxic activities were detected for the aqueous, methanol, ethyl acetate, or n-butanolic extracts. In the in vivo analysis, crude A. blazei was given orally after carcinogen treatment in a rat medium-term study (20 weeks) of colon carcinogenesis using aberrant crypt foci (ACF) as biomarker. Male Wistar rats were given dimethylhydrazine (DMH) and then were fed A. blazei at 5% in the diet until Week 20. ACF were scored for number and crypt multiplicity. A. blazei intake did not suppress ACF development or crypt multiplicity induced by DMH. No differences in tumor incidence in the colon were observed among the DMH-treated groups. Our results indicate that employing A. blazei in the diet does not have a suppressive effect on colon carcinogenesis.

Lack of chemoprevention of dietary Agaricus blazei against rat colonic aberrant crypt foci

The mushroom Agaricus blazei (Ab) has been widely used in folk medicine to treat various diseases including cancer. No information is available on its possible protective effects on the development of colon cancer. The potential blocking effect of Ab intake on the initiation stage of colon carcinogenesis was investigated in a short-term (4-week) bioassay using aberrant crypt foci (ACF) as biomarker. Male Wistar rats were given four subcutaneous injections of the carcinogen 1,2-dimethylhydrazine (DMH, 40 mg/kg bw, twice a week), during 2 weeks to induce ACF. The diet containing Ab at 5% was given 2 weeks before and during carcinogen treatment to investigate the potential beneficial effects of this edible mushroom on DMH-induced ACF. All groups were killed at the end of the fourth week. The colons were analyzed for ACF formation in 1% methylene blue whole-mount preparations and for cell proliferation in histological sections immunohistochemically stained for the proliferating cell nuclear antigen (PCNA). All DMH-treated rats developed ACF mainly in the middle and distal colon. Agaricus blazei intake at 5% did not alter the number of ACF induced by DMH or the PCNA indices in the colonic mucosa. Thus, the results of the present study did not confirm a chemopreventive activity of Ab on the initiation stage of rat colon carcinogenesis.

Lycopene activity against chemically induced DNA damage in Chinese hamster ovary cells

Lycopene is a natural pigment synthesized by plants and microorganisms, and it is mainly found in tomatoes. It is an acyclic isomer of beta-carotene and one of the most potent antioxidants. Several studies have demonstrated the ability of lycopene to prevent chemically induced DNA damage; however, the mechanisms involved are still not clear. In the present study, we investigated the antigenotoxic/antimutagenic effects of lycopene in Chinese Hamster Ovary Cells (CHO) treated with hydrogen peroxide, methylmethanesulphonate (MMS), or 4-nitroquinoline-1-oxide (4-NQO). Lycopene (97%), at final concentrations of 10, 25, and 50 microM, was tested under three different protocols: before, simultaneously, and after the treatment with the mutagens. Comet and cytokinesis-block micronucleus assays were used to evaluate the level of DNA damage. Data showed that lycopene reduced the frequency of micronucleated cells induced by the three mutagens. However, this chemopreventive activity was dependent on the concentrations and treatment schedules used. Similar results were observed in the comet assay, although some enhancements of primary DNA damage were detected when the carotenoid was administered after the mutagens. In conclusion, our findings confirmed the chemopreventive activity of lycopene, and showed that this effect occurs under different mechanisms.

Chemopreventive property of dietary ginger in rat urinary bladder chemical carcinogenesis

The modifying potential of ginger on the development of preneoplasia and tumors in the male Wistar rat urinary bladder was investigated in a 36-week-long initiation-promotion assay for chemical carcinogenesis. Groups G1 to G3 were given 0.05% N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) in drinking water for 5 weeks and a 3% uracil meal for the subsequent 3 weeks. Groups G4 and G5 were treated with 3% uracil only for the same period. After these steps, groups G2, and G3 and G4 were fed for 26 weeks a ginger extract mixed at 0.5 and 1.0% in a basal diet, respectively. Thirty six weeks after the beginning of the experiment all rats were killed. The multiplicity of urothelial lesions (hyperplasia and neoplasia) was significantly lower (P = 0.013) in group G3 than in groups G1 and G2. The results suggest that 1.0% ginger meal exerts a protective effect on the post-initiation stage of rat chemically-induced urothelial carcinogenesis.

Effects of ginger (Zingiber officinale Roscoe) on DNA damage and development of urothelial tumors in a mouse bladder carcinogenesis model

Extracts of the spice ginger (Zingiber officinale Roscoe) are rich in gingerols and shogaols, which exhibit antioxidant, anti-inflammatory, antifungal, antimycobacterial, and anticarcinogenic proprieties. The present study evaluated the chemoprotective effects of a ginger extract on the DNA damage and the development of bladder cancer induced by N-butyl-N-(4-hydroxibutyl) nitrosamine (BBN)/N-methyl-N-nitrosourea (MNU) in male Swiss mice. Groups G1-G3 were given 0.05% BBN in drinking water for 18 weeks and four i.p. injections of 30 mg/kg body weight MNU at 1, 3, 10, and 18 weeks. Group G4 and G5 received only the BBN or MNU treatments, respectively, and groups G6 and G7 were not treated with BBN or MNU. Additionally, Groups G2, G3, and G6 were fed diets containing 1, 2, and 2% ginger extract, respectively, while Groups G1, G4, G5, and G7 were fed basal diet. Samples of peripheral blood were collected during the experiment for genotoxicity analysis; blood collected 4 hr after each MNU dose was used for the analysis of DNA damage with the Comet assay (assay performed on leukocytes from all groups), while reticulocytes collected 24 hr after the last MNU treatment of Groups G5-G7 were used for the micronucleus assay. At the end of the experiment, the urinary bladder was removed, fixed, and prepared for histopathological, cell proliferation, and apoptosis evaluations. Ginger by itself was not genotoxic, and it did not alter the DNA damage levels induced by the BBN/MNU treatment during the course of the exposure. The incidence and multiplicity of simple and nodular hyperplasia and transitional cell carcinoma (TCC) were increased by the BBN/MNU treatment, but dietary ginger had no significant effect on these responses. However, in Group G2 (BBN/MNU/2% ginger-treated group), there was an increased incidence of Grade 2 TCC. The results suggest that ginger extract does not inhibit the development of BBN-induced mouse bladder tumors.

Lack of chemopreventive effects of ginger on colon carcinogenesis induced by 1,2-dimethylhydrazine in rats

Ginger (Zingiber officinale Roscoe) has been proposed as a promising candidate for cancer prevention. Its modifying potential on the process of colon carcinogenesis induced by 1,2-dimethylhydrazine (DMH) was investigated in male Wistar rats using the aberrant crypt foci (ACF) assay. Five groups were studied: Groups 1-3 were given four s.c. injections of DMH (40 mg/kg b.w.) twice a week, during two weeks, whereas Groups 4 and 5 received similar injections of EDTA solution (DMH vehicle). After DMH-initiation, the animals were fed a ginger extract mixed in the basal diet at 0.5% (Group 2) and 1.0% (Groups 3 and 4) for 10 weeks. All rats were killed after 12 weeks and the colons were analyzed for ACF formation and crypt multiplicity. The rates of cell proliferation and apoptosis were also evaluated in epithelial colonic crypt cells. Dietary consumption of ginger at both dose levels did not induce any toxicity in the rats, but ginger meal at 1% decreased significantly serum cholesterol levels (p<0.038). Treatment with ginger did not suppress ACF formation or the number of crypts per ACF in the DMH-treated group. Dietary ginger did not significantly change the proliferative or apoptosis indexes of the colonic crypt cells induced by DMH. Thus, the present results did not confirm a chemopreventive activity of ginger on colon carcinogenesis as analyzed by the ACF bioassay and by the growth kinetics of the colonic mucosa.

Absence of carcinogenic and anticarcinogenic effects of annatto in the rat liver medium-term assay

Annatto (Bixa orellana L.) is a natural food colorant extensively used in many processed foods, especially dairy products. The lower cost of production and the low toxicity, make annatto a very attractive and convenient pigment in substitution to the many synthetic colorants. In the present study we investigate the carcinogenic and anticarcinogenic effects of dietary annatto in Wistar rat liver using the preneoplastic glutathione S-transferase (GST-P) foci and DNA damage biomarkers. Annatto, containing 5% bixin, was administered in the diet at concentrations of 20, 200, and 1000 ppm (0.07; 0.80 and 4.23 bixin/kg body wt/day, respectively), continuously during 2 weeks before, or 8 weeks after DEN treatment (200 mg/kg body wt, i.p.), to evaluate its effect on the liver-carcinogenesis medium-term bioassay. The comet assay was used to investigate the modifying potential of annatto on DEN (20 mg/kg body wt)-induced DNA damage. The results showed that annatto was neither genotoxic nor carcinogenic at the highest concentration tested (1000 ppm). No protective effects were also observed in both GST-P foci development and comet assays. In conclusion, in such experimental conditions, annatto shows no hepatocarcinogenic effect or modifying potential against DEN-induced DNA damage and preneoplastic foci in the rat liver.

Chemically induced immunotoxicity in a medium-term multiorgan bioassay for carcinogenesis with Wistar rats

A variety of chemicals can adversely affect the immune system and influence tumor development. The modifying potential of chemical carcinogens on the lymphoid organs and cytokine production of rats submitted to a medium-term initiation-promotion bioassay for carcinogenesis was investigated. Male Wistar rats were sequentially initiated with N-nitrosodiethylamine (DEN), N-methyl-N-nitrosourea (MNU), N-butyl-N-(4hydroxybutyl)nitrosamine (BBN), dihydroxy-di-n-propylnitrosamine (DHPN), and 1,2-dimethylhydrazine (DMH) during 4 weeks. Two initiated groups received phenobarbital (PB) or 2-acetylaminofluorene (2-AAF) for 25 weeks and two noninitiated groups received only PB or 2-AAF. A nontreated group was used as control. Lymphohematopoietic organs, liver, kidneys, lung, intestines, and Zymbal's gland were removed for histological analysis. Interleukin (IL)-2, IL-12, interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), IL-10, and transforming growth factor beta1 (TGF-beta1) levels were determined by ELISA in spleen cell culture supernatants. At the fourth week, exposure to the initiating carcinogens resulted in cell depletion of the thymus, spleen and bone marrow, and impairment of IL-2, IL-12, and IFN-gamma production. However, at the 30th week, no important alterations were observed both in lymphoid organs and cytokine production in the different groups. The results indicate that the initiating carcinogens used in the present protocol exert toxic effects on the lymphoid organs and affect the production of cytokines at the initiation step of carcinogenesis. This early and reversible depression of the immune surveillance may contribute to the survival of initiated cells facilitating the development of future neoplasia.

Chemoprevention of preneoplastic liver foci development by dietary mushroom Agaricus blazei Murrill in the rat

The chemopreventive potential of an Agaricus blazei (Ab) Murrill mushroom meal was investigated in a medium-term rat liver carcinogenesis assay. Male Wistar rats initiated for hepatocarcinogenesis with diethylnitrosamine (DEN, 200 mg/kg i.p.) were fed during a 6-week period with the dry powdered mushroom strains Ab 29 or 26, each one with opened (OB) or closed basidiocarp (CB), mixed at 10% level in a basal diet. All experimental animals and controls were subjected to partial hepatectomy at week 3 and killed at week 8. Chemopreventive activity of the mushroom meal was observed for the Ab 29 (OB and CB) and Ab 26 (CB) strains in terms of the number of putative preneoplastic altered foci of hepatocytes which express either the enzyme glutathione S-transferase, placental form (GST-P+) or the transforming growth factor-alpha, and for the Ab 29 (OB) and Ab 26 (CB) strains on the size of GST-P+ foci. This was associated with inhibition of foci cell proliferation in the animals fed the Ab 29 (OB) and Ab 26 (CB) strains. The results suggest that the protective influence of the Ab meal against the DEN potential for rat liver carcinogenicity depends on both the strain and period of mushroom harvest.

Effects of crude extracts of Agaricus blazei on DNA damage and on rat liver carcinogenesis induced by diethylnitrosamine

The effects of crude extracts of the mushroom Agaricus blazei Murrill (Agaricaceae) on both DNA damage and placental form glutathione S-transferase (GST-P)-positive liver foci induced by diethylnitrosamine (DEN) were investigated. Six groups of adult male Wistar rats were used. For two weeks, animals of groups 3 to 6 were treated with three aqueous solutions of A. blazei (mean dry weight of solids being 1.2, 5.6, 11.5 and 11.5 mg/ml, respectively). After this period, groups 2 to 5 were given a single ip injection 200 mg/kg DEN and groups 1 and 6 were treated with 0.9% NaCl. All animals were subjected to 70% partial hepatectomy at week five and sacrificed 4, 24 and 48 h or 8 weeks after DEN or 0.9% NaCl treatments (10th week after the beginning of the experiment). The alkaline comet assay and GST-P-positive liver foci development were used to evaluate the influence of the mushroom extracts on liver cell DNA damage and on the initiation of liver carcinogenesis, respectively. Previous treatment with the highest concentration of A. blazei (11.5 mg/ml) significantly reduced DNA damage, indicating a protective effect against DEN-induced liver cytotoxicity/genotoxicity. However, the same dose of mushroom extract significantly increased the number of GST-P-positive liver foci.

Agaricus blazei (Himematsutake) does not alter the development of rat diethylnitrosamine-initiated hepatic preneoplastic foci

The modifying potential of crude extracts of the mushroom Agaricus blazei Murrill (Himematsutake) on the development and growth of glutathione S-transferase placental form (GST-P)-positive liver foci (liver preneoplastic lesion) was investigated in adult male Wistar rats. Six groups of animals were used. Groups 2 to 5 were given a single i.p. injection of 200 mg/kg b.w. of diethylnitrosamine (DEN) and groups 1 and 6 were treated with saline at the beginning of the experiment. After 2 weeks, animals of groups 3 to 6 were orally treated with three dose levels of aqueous extracts of the mushroom A. blazei (1.2, 5.6, 11.5, and 11.5 mg/ml of dry weight of solids) for 6 weeks. All animals were subjected to two-thirds partial hepatectomy at week 3 and sacrificed at week 8. Two hours before sacrifice, ten animals of each group were administered a single i.p injection of 100 mg/kg of bromodeoxyuridine (BrdU). Apoptotic bodies and BrdU-positive hepatocyte nuclei were quantified in liver sections stained for hematoxylin and eosin (H&E) (eosinophilic foci) and simultaneously stained for GST-P expression (GST-P-positive foci), respectively. The 6-week treatment with A. blazei did not alter the development (number and size) of GST-P-positive foci and did not affect the growth kinetics of liver normal parenchyma or foci in DEN-initiated animals. Our results indicate that the treatment with aqueous extracts of the mushroom A. blazei during the post-initiation stage of rat liver carcinogenesis does not exert any protective effect against the development of GST-P-positive foci induced by DEN.

Influence of aqueous extract of Agaricus blazei on rat liver toxicity induced by different doses of diethylnitrosamine

The modifying potential of prior administration of an aqueous extract of the mushroom Agaricus blazei Murrill (Agaricaceae) (Ab) on hepatotoxicity induced by different doses of diethylnitrosamine (DEN) in male Wistar rats was evaluated. During 2 weeks, animals of groups G3 (Ab+DEN(50)), G5 (Ab+DEN(100)), G7 (Ab+DEN(200)), and G8 (Ab-treated) were treated with the A. blazei through drinking water. After this period, groups G2 (DEN(50)), G3 (Ab+DEN(50)), G4 (DEN(100)) G5 (Ab+DEN(100)), G6 (DEN(200)), and G7 (Ab+DEN(200)) were given a single i.p. injection of 50, 100 and 200 mg/kg of DEN, respectively, while groups G1 (non-treated) and G8 (Ab-treated) were treated with 0.9% NaCl only. All animals were killed 48 h after DEN or NaCl treatments. The hepatocyte replication rate was estimated by the index of the proliferating cell nuclear antigen (PCNA) positive hepatocytes and the appearance of putative preneoplastic hepatocytes through expression of the enzyme glutathione S-transferase placental form (GST-P). After DEN-treatment, ALT levels, PCNA labeling index, and the number of GST-P positive hepatocytes were lower in rats that received A. blazei treatment and were exposed to 100 mg/kg of DEN. Our findings suggest that previous treatment with A. blazei exerts a hepatoprotective effect on both liver toxicity and hepatocarcinogenesis process induced by a moderately toxic dose of DEN.