Tumors In Male Mice Research Articles

Resistance Training and Resveratrol Supplementation Improve Cancer Cachexia and Tumor Volume in Muscle Tissue of Male Mice Bearing Colon Cancer CT26 Cell Tumors.

Losing muscle functions due to reducing muscle mass and quality is one of the main features of cancer cachexia that impairs patients' quality of life and decrease their survival. This study aimed to investigate the synergistic effects of resistance training and resveratrol supplementation on cachexia induced by CT26 tumors in male mice. Forty-eight mice were divided into eight groups randomly: healthy sedentary vehicle (HSV), healthy exercise vehicle (HEV), healthy sedentary resveratrol (HSR), healthy exercise resveratrol (HER), CT-26 tumor-bearing sedentary vehicle (TSV), CT-26 tumor-bearing exercise vehicle (TEV), CT-26 tumor-bearing sedentary resveratrol (TSR) and CT-26 tumor-bearing exercise resveratrol (TER). Training groups performed ladder climbing with weights tied to their tails, for six weeks. Resveratrol-treated groups received 50 mg/kg daily by gavage. The results showed muscle weight, and mTORC1 phosphorylation decreased in TSV compared to the HSV group. mTORC1 phosphorylation was increased in TER compared to TSV, TEV, and TSR. In addition, AMPK phosphorylation was more elevated in HER compared to HSV, HEV, and HSR. LC3BII/I ratio was higher in TSV than HSV group. Tumor volume was increased in all groups, with the lowest increase in TER group. In tumor tissue, mTORC1 phosphorylation was decreased in TER than in TSV, TEV, and TSR groups; AMPK phosphorylation and LC3BII/I ratio were increased in TSV than in TEV, TSR, and TER groups. In conclusion, the synergistic effect of resistance training and resveratrol supplementation is the most effective in reducing tumor volume. These advantages were mostly in line with molecular findings.

Protective Effects of Hepatocyte Stress Defenders, Nrf1 and Nrf2, against MASLD Progression.

Progression of metabolic dysfunction-associated steatites liver disease (MASLD) to steatohepatitis (MASH) is driven by stress-inducing lipids that promote liver inflammation and fibrosis, and MASH can lead to cirrhosis and hepatocellular carcinoma. Previously, we showed coordinated defenses regulated by transcription factors, nuclear factor erythroid 2-related factor-1 (Nrf1) and -2 (Nrf2), protect against hepatic lipid stress. Here, we investigated protective effects of hepatocyte Nrf1 and Nrf2 against MASH-linked liver fibrosis and tumorigenesis. Male and female mice with flox alleles for genes encoding Nrf1 (Nfe2l1), Nrf2 (Nfe2l2), or both were fed a MASH-inducing diet enriched with high fat, fructose, and cholesterol (HFFC) or a control diet for 24-52 weeks. During this period, hepatocyte Nrf1, Nrf2, or combined deficiency for ~7 days, ~7 weeks, and ~35 weeks was induced by administering mice hepatocyte-targeting adeno-associated virus (AAV) expressing Cre recombinase. The effects on MASH, markers of liver fibrosis and proliferation, and liver tumorigenesis were compared to control mice receiving AAV-expressing green fluorescent protein. Also, to assess the impact of Nrf1 and Nrf2 induction on liver fibrosis, HFFC diet-fed C57bl/6J mice received weekly injections of carbon tetrachloride, and from week 16 to 24, mice were treated with the Nrf2-activating drug bardoxolone, hepatocyte overexpression of human NRF1 (hNRF1), or both, and these groups were compared to control. Compared to the control diet, 24-week feeding with the HFFC diet increased bodyweight as well as liver weight, steatosis, and inflammation. It also increased hepatocyte proliferation and a marker of liver damage, p62. Hepatocyte Nrf1 and combined deficiency increased liver steatosis in control diet-fed but not HFFC diet-fed mice, and increased liver inflammation under both diet conditions. Hepatocyte Nrf1 deficiency also increased hepatocyte proliferation, whereas combined deficiency did not, and this also occurred for p62 level in control diet-fed conditions. In 52-week HFFC diet-fed mice, 35 weeks of hepatocyte Nrf1 deficiency, but not combined deficiency, resulted in more liver tumors in male mice, but not in female mice. In contrast, hepatocyte Nrf2 deficiency had no effect on any of these parameters. However, in the 15-week CCL4-exposed and 24-week HFFC diet-fed mice, Nrf2 induction with bardoxolone reduced liver steatosis, inflammation, fibrosis, and proliferation. Induction of hepatic Nrf1 activity with hNRF1 enhanced the effect of bardoxolone on steatosis and may have stimulated liver progenitor cells. Physiologic Nrf1 delays MASLD progression, Nrf2 induction alleviates MASH, and combined enhancement synergistically protects against steatosis and may facilitate liver repair.

Acidity-activatable upconversion afterglow luminescence cocktail nanoparticles for ultrasensitive in vivo imaging

Activatable afterglow luminescence nanoprobes enabling switched “off-on” signals in response to biomarkers have recently emerged to achieve reduced unspecific signals and improved imaging fidelity. However, such nanoprobes always use a biomarker-interrupted energy transfer to obtain an activatable signal, which necessitates a strict distance requisition between a donor and an acceptor moiety (<10 nm) and hence induces low efficiency and non-feasibility. Herein, we report organic upconversion afterglow luminescence cocktail nanoparticles (ALCNs) that instead utilize acidity-manipulated singlet oxygen (1O2) transfer between a donor and an acceptor moiety with enlarged distance and thus possess more efficiency and flexibility to achieve an activatable afterglow signal. After in vitro validation of acidity-activated afterglow luminescence, ALCNs achieve in vivo imaging of 4T1-xenograft subcutaneous tumors in female mice and orthotopic liver tumors in male mice with a high signal-to-noise ratio (SNR). As a representative targeting trial, Bio-ALCNs with biotin modification prove the enhanced targeting ability, sensitivity, and specificity for pulmonary metastasis and subcutaneous tumor imaging via systemic administration of nanoparticles in female mice, which also implies the potential broad utility of ALCNs for tumor imaging with diverse design flexibility. Therefore, this study provides an innovative and general approach for activatable afterglow imaging with better imaging performance than fluorescence imaging.

Promising growth inhibitory potential of extracted natural silk sericin biopolymer against DEN‐induced liver tumor in male mice

AbstractSilk sericin (SS), a protein biopolymer, is gaining an increasing attention in a variety of biomedical applications. Our objective was to identify the optimal extraction method yielding the highest silk protein content, to assess its chemical elemental composition, to characterize it, and to compare its conformation by X‐ray diffraction and Fourier‐transform infrared versus that of the commercial one. Herein, alkali and high temperature is the perfect approach. This study aimed further to test whether extracted SS could attenuate the adverse hepatotoxic effects induced by diethylnitrosamine (DEN) in mice. Animals were injected intraperitoneally once weekly for four consecutive weeks with physiological saline (0.9% NaCl), DEN (25 mg/kg), SS (1 g/kg) 90 min prior to DEN injection, melatonin (10 mg/kg) followed within 1 h with the administration of SS and 30 min later with DEN. The results confirmed the hepatotoxicity of DEN manifested by an increase in liver enzymes' activity, and pathological changes in the liver tissue. The combined use of SS and/or melatonin with DEN returned most of the parameters to values similar to the controls. Briefly, chemically characterized SS seems a valuable extract for further consideration as anti‐carcinogenic agent. It has the potential to upgrade liver cancer chemotherapeutic agents.

Transplantation of mitochondria from human malignant tumor cells as a method of tumor growth formation in the lungs of laboratory animals

Purpose of the study. Obtaining lung cancer tumors in Balb/c Nude mice by transplantation of mitochondria isolated from human malignant tumors.Materials and methods. Human lung cancer mitochondria were isolated using differential centrifugation on a high-speed refrigerated centrifuge. Mitochondrial samples were diluted with 0.9 % NaCl solution to a protein concentration of 3 mg per animal. Freshly isolated lung cancer mitochondria were once transplanted into the tail vein of male Balb/c Nude mice (n = 6) at the rate of 3 mg of protein per 1 animal in 0.4 ml of saline. Male mice of Balb/c Nude line (n = 4), which were injected with 0.4 ml of physiological solution into the tail vein once a day, served as a control group. All animals were killed by guillotine decapitation 4 months after intravenous transplantation of mitochondria isolated from lung cancer.Results. After the introduction of mitochondria into the tail vein of mice, no changes were found in the animals’ behavior, coloration of coverings. No respiratory problems, and no allergic reactions to the introduction of foreign protein were detected. Respiratory problems in mice with mitochondrial transplantation occurred between days 113 and 123, when a drop in body weight ≥ 25 % was observed. A uniform formation of tumor nodes together with an active filling of the lung space with blood was clearly visible on lung preparations of a Balb/c Nude male mouse after intravenous transplantation of mitochondria from the lung of a patient with non-keratinizing squamous cell carcinoma. Similar characteristics of tumor growth in the lung parenchyma of the patient and Balb/c Nude mice as direct recipients of tumor mitochondria involved solid structures consisting of fields, cells and strands of tightly fitting atypical polymorphic cells of the squamous epithelium with poorly developed cytoplasm. In addition, signs of adenocarcinoma included glandular and papillary-like structures and cell complexes with large nucleoli. Squamous epithelial cells were characterized by severe atypia and polymorphism. The shape of the nuclei was irregular in most cells, with large sizes, the color was heterogeneous, and the nucleoli were enlarged. Multinucleated cells, as well as pathological mitoses with clearly marked division figures, which testified to their proliferative activity, were encountered with a rather high frequency.Conclusions. Application of intravenous transplantation of mitochondria isolated from malignant human lung tumor in male mice of Balb/c Nude line causes growth and development of malignant foci in male Balb/c Nude mice. This is previously unknown fact in experimental oncology, allowing the study of new properties of mitochondria of human cancer cells.

Evaluation of the mode of action and human relevance of liver tumors in male mice treated with epyrifenacil

Epyrifenacil (trademark name: Rapidicil®), a novel protoporphyrinogen oxidase (PPO)-inhibiting herbicide, induces hepatocellular adenomas and carcinomas in male CD-1 mice after 78 weeks treatment. The mode of action (MOA) of these mouse liver tumors and their relevance to humans was assessed based on the 2006 International Programme on Chemical Safety (IPCS) Human Relevance Framework. Epyrifenacil is not genotoxic and induced liver tumors via the postulated porphyria-mediated cytotoxicity MOA with the following key events: (#1) PPO inhibition; (#2) porphyrin accumulation; (#3) hepatocellular injury; with (#4) subsequent regenerative cell proliferation; and ultimately (#5) development of liver tumors. This article evaluates the weight of evidence for this MOA based on the modified Bradford Hill criteria. The MOA data were aligned with the dose and temporal concordance, biological plausibility, coherence, strength, consistency, and specificity for a porphyria-mediated cytotoxicity MOA while excluding other alternative MOAs. Although the postulated MOA could qualitatively potentially occur in humans, we demonstrate that it is unlikely to occur in humans because of quantitative toxicodynamic and toxicokinetic differences between mice and humans. Therefore, this MOA is considered not relevant to humans, utilizing the IPCS Human Relevance Framework; consequently, a nonlinear, threshold dose response would be appropriate for human risk assessment.

Risk Assessment of the Fungicide Luna Privilege with the Active Substance Fluopyram

Luna Privilege is a new fungicide for use in apples, pears, outdoor and indoor strawberries, outdoor and indoor lettuces, peas, beans and indoor tomatoes, and contains the new active substance fluopyram.&#x0D; VKM was requested by the Norwegian Food Safety Authority to consider the possible health risk for operators related to the properties of Luna Privilege and fluopyram; in particular to evaluate the potential for bioaccumulation, reproductive and neurotoxic effects, and discuss possible mechanisms involved in liver and thyroid tumor formation observed in rats, and the establishment of NOAELs and reference values.&#x0D; VKM was also asked to evaluate the fate and behaviour of fluopyram in the environment, and the ecotoxicological effects and risks related to its use, in particular the potential for groundwater contamination, safety margins and possible effects on birds and aquatic organisms.&#x0D; The assessment was finalized in a meeting on December 13. 2013 by VKM’s Panel on Plant Protection Products.&#x0D; VKM’s conclusions are as follows:&#x0D; Health:&#x0D; It is the opinion of VKM that:&#x0D; &#x0D; The active ingredient fluopyram has low potential for bioaccumulation, and the data do not suggest a sex-specific excretion.&#x0D; &#x0D; &#x0D; &#x0D; An in vivo Comet Assay in rat liver could help to further elucidate the genotoxic potential of fluopyram.&#x0D; &#x0D; &#x0D; &#x0D; It can not be excluded that the reported incidence of “gall bladder absent” is treatment related.&#x0D; &#x0D; &#x0D; &#x0D; NOAEL for the 90-day feeding study in rats should be set to 3.06 mg/kg bw/day, resulting in an AOEL of 0.03 mg/kg bw/day.&#x0D; &#x0D; &#x0D; &#x0D; The “dumb-bell or incomplete ossification and/or bipartite/normal cartilage” should be considered as a malformation and regarded as treatment related.&#x0D; &#x0D; &#x0D; &#x0D; The time points used for neurotoxic measurements are not optimal to detect neurotoxic effects from acute exposure, since the time window between the first and second measurements is too long.&#x0D; &#x0D; &#x0D; &#x0D; The studies where effects of fluopyram and phenobarbital are compared can not be used to exclude human relevance of the tumor-inducing effect of fluopyram in the liver of female rats.&#x0D; &#x0D; &#x0D; &#x0D; The results from the mechanistic studies are insufficient to support the proposed mode of action for the induction of thyroid follicular cell tumors in male mice, and thus the induction of thyroid tumors in male mice could be relevant for humans.&#x0D; &#x0D; VKM proposes:&#x0D; &#x0D; &#x0D; NOAEL of 1.2 mg/kg bw/day based on a 2 year feeding study in rats.&#x0D; &#x0D; &#x0D; &#x0D; ADI: 0.012 mg/kg bw/day&#x0D; &#x0D; &#x0D; &#x0D; AOEL: 0.03 mg/kg bw/day&#x0D; &#x0D; &#x0D; &#x0D; ARfD: 0.25 mg/kg bw/day&#x0D; &#x0D; &#x0D; Risk calculations for field use of Luna Privilege show minimal risk if personal protective equipment is used. The AOEL of fluopyram for greenhouse use is not exceeded, even without protective equipment. Re-entry and bystander exposure is calculated to be well below the AOEL.&#x0D; Environment:&#x0D; It is the opinion of VKM that:&#x0D; &#x0D; Worst case degradation rates from laboratory studies should preferably be used to calculate PECsoil values for fluopyram.&#x0D; Both fluopyram and fluopyram-7-hydroxy have a high potential for groundwater contamination.&#x0D; &#x0D; &#x0D; &#x0D; The efficacy of buffer zones needs to be considered on a case-by-case basis, and further validation of values for efficacy from the model simulation is necessary.&#x0D; &#x0D; &#x0D; &#x0D; It is further the opinion of VKM that all the refinements used in the risk assessment for birds are relevant. Since the TER values estimated for all crops except for orchards are below the trigger following refinements, it is the view of VKM that the data indicate medium risk for strawberries and pulses, and high risk for lettuce in open field.&#x0D; &#x0D; &#x0D; &#x0D; The use of LC50 values for fluopyram in the TER calculations with a TER trigger value of 100 is overly conservative, and a reduction of the acute trigger for both invertebrates and fish from 100 to 10 for such calculations are suggested.&#x0D; &#x0D; &#x0D; &#x0D; The trigger for acute toxicity is not exceeded for any of the crops. For chronic toxicity, VKM concludes that there is a moderate risk for effects on fish when Luna Privilege is applied to beans/strawberries without the use of a vegetated mitigation buffer-strip.&#x0D;

Modeling of multiple primary malignant tumors in experiment

Purpose of the study. Creation and study of models of primary multiple malignant tumors (MMPT model) under experimental conditions.Materials and methods. The study was carried out involving male and female BALB/c Nude mice (n = 42). Experimental groups of mice: with melanoma B16/F10 (B16/F10), males (control 1) and females (control 3) by n = 7; control 2 – with sarcoma 45 (C45), males n = 7; control 4 – with Guerin carcinoma (KG), females n = 7; basic: MMPT model No. 1 – B16/F10 and S45, males n = 7, and MMPT model No. 2 – B16/F10 and GC, females n = 7. 0.5 ml suspension of murine B16/F10 melanoma tumor cells diluted in the saline proportions 1:20 was injected under the skin of the left dorsal side to all animals with MMPT model, as well as 0.5 ml of a suspension containing 0.50 × 106 S45 or GC tumor cells in the saline under the skin on the right dorsum. Control groups received the same amount of tumors as the MMPT model.Results. Tumors in male mice in MMPT model No. 1 appeared simultaneously and significantly earlier than in controls: В16/ F10 melanoma by 3 times, S45 by 2 times. Tumor zises in MMPT model No. 1 were larger than in the corresponding controls: by 8.5 times at the area of В16/F10 melanoma inoculation and by 2.2 times at the area of S45 inoculation. Melanoma metastasized under the S45 capsule. Tumor at the area of GC transplantation in MMPT model No. 2 grew 5 times faster than at the area of В16/F10 melanoma injection; both tumors appeared on average 3 times earlier than in control groups 3 and 4. Tumor volumes in MMPT model No. 2 were larger than in the corresponding controls: by 7.5 times at the area of В16/F10 melanoma inoculation and by 2.2 times at the area of GC inoculation. However, almost the entire volume of the tumor node in the area of B16/F10 melanoma transplantation was represented by GC tumor tissue due to metastasis from the primary GC tumor. Melanoma remained as a small black spot with a diameter of 5–6 mm at the area of its inoculation under the skin. The average survival of mice in MMPT models No. 1 and No. 2 was 1.5–2 times (p &lt; 0.05) lower than in the corresponding controls.Conclusions. Sequential subcutaneous transplantation of mouse B16/F10 melanoma and rat sarcoma 45 to BALB/c Nude mice increased the malignant potential of each tumor: the time of their onset was shorter, and the growth rate of tumors increased which decreased the survival of animals. Sequential subcutaneous transplantation of mouse B16/F10 melanoma and Guerin's rat carcinoma to female BALB/c Nude mice suppressed tumor growth of B16/F10 melanoma and increased the malignant potential of rat GC.

Hepatic Tumor Formation in Adult Mice Developmentally Exposed to Organotin.

Background:Tributyltin (TBT) is a persistent and bioaccumulative environmental toxicant. Developmental exposure to TBT has been shown to cause fatty liver disease (steatosis), as well as increased adiposity in many species, leading to its characterization as an obesogen.Objective:We aimed to determine the long-term effects of developmental TBT exposure on the liver.Methods:C57BL/6J mice were exposed to a dose of TBT ( body weight per day; ) below the current developmental no observed adverse effect level (NOAEL) via drinking water, or drinking water alone, provided to the dam from preconception through lactation. Sires were exposed during breeding and lactation. Pups from two parity cycles were included in this study. Animals were followed longitudinally, and livers of offspring were analyzed by pathological evaluation, immunohistochemistry, immunoblotting, and RNA sequencing.Results:Developmental exposure to TBT led to increased adiposity and hepatic steatosis at 14 and 20 weeks of age and increased liver adenomas at 45 weeks of age in male offspring. Female offspring displayed increased adiposity as compared with males, but TBT did not lead to an increase in fatty liver or tumor development in female offspring. Liver tumors in male mice were enriched in pathways and gene signatures associated with human and rodent nonalcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC). This includes down-regulation of growth hormone receptor (GHR) and of STAT5 signaling, which occurred in response to TBT exposure and preceded liver tumor development.Conclusions:These data reveal a previously unappreciated ability of TBT to increase risk for liver tumorigenesis in mice in a sex-specific manner. Taken together, these findings provide new insights into how early life environmental exposures contribute to liver disease in adulthood. https://doi.org/10.1289/EHP5414

Perfluorocarbon nanodroplets can reoxygenate hypoxic tumors in vivo without carbogen breathing.

Nanoscale perfluorocarbon (PFC) droplets have enormous potential as clinical theranostic agents. They are biocompatible and are currently used in vivo as contrast agents for a variety of medical imaging modalities, including ultrasound, computed tomography, photoacoustic and 19F-magnetic resonance imaging. PFC nanodroplets can also carry molecular and nanoparticulate drugs and be activated in situ by ultrasound or light for targeted therapy. Recently, there has been renewed interest in using PFC nanodroplets for hypoxic tumor reoxygenation towards radiosensitization based on the high oxygen solubility of PFCs. Previous studies showed that tumor oxygenation using PFC agents only occurs in combination with enhanced oxygen breathing. However, recent studies suggest that PFC agents that accumulate in solid tumors can contribute to radiosensitization, presumably due to tumor reoxygenation without enhanced oxygen breathing. In this study, we quantify the impact of oxygenation due to PFC nanodroplet accumulation in tumors alone in comparison with other reoxygenation methodologies, in particular, carbogen breathing.Methods: Lipid-stabilized, PFC (i.e., perfluorooctyl bromide, CF3(CF2)7Br, PFOB) nanoscale droplets were synthesized and evaluated in xenograft prostate (DU145) tumors in male mice. Biodistribution assessment of the nanodroplets was achieved using a fluorescent lipophilic indocarbocyanine dye label (i.e., DiI dye) on the lipid shell in combination with fluorescence imaging in mice (n≥3 per group). Hypoxia reduction in tumors was measured using PET imaging and a known hypoxia radiotracer, [18F]FAZA (n≥ 3 per group).Results: Lipid-stabilized nanoscale PFOB emulsions (mean diameter of ~250 nm), accumulated in the xenograft prostate tumors in mice 24 hours post-injection. In vivo PET imaging with [18F]FAZA showed that the accumulation of the PFOB nanodroplets in the tumor tissues alone significantly reduced tumor hypoxia, without enhanced oxygen (i.e., carbogen) breathing. This reoxygenation effect was found to be comparable with carbogen breathing alone.Conclusion: Accumulation of nanoscale PFOB agents in solid tumors alone successfully reoxygenated hypoxic tumors to levels comparable with carbogen breathing alone, an established tumor oxygenation method. This study confirms that PFC agents can be used to reoxygenate hypoxic tumors in addition to their current applications as multifunctional theranostic agents.

Transcriptional profiling of male CD-1 mouse lungs and Harderian glands supports the involvement of calcium signaling in acrylamide-induced tumors

Acrylamide (AA) exposure causes increased incidence of forestomach, lung, and Harderian gland tumors in male mice. One hypothesized mode of action (MOA) for AA-carcinogenicity includes genotoxicity/mutagenicity as a key event, possibly resulting from AA metabolism to the direct genotoxic metabolite glycidamide. Alternatively, altered calcium signaling (CS) has been proposed as a central key event in the MOA. To examine the plausibility of these proposed MOAs, RNA-sequencing was performed on tumor target tissues: Harderian glands (the most sensitive tumor target tissue in the rodent 2-year cancer bioassay) and lungs of AA-exposed male CD-1 mice. Animals were exposed to 0.0, 1.5, 3.0, 6.0, 12.0, or 24.0 mg AA/kg bw-day in drinking water for 5, 15, or 31 days. We observed a pronounced effect on genes involved in CS and cytoskeletal processes in both tissues, but no evidence supporting a genotoxic MOA. Benchmark dose modeling suggests transcriptional points of departure (PODs) of 0.54 and 2.21 mg/kg bw-day for the Harderian glands and lungs, respectively. These are concordant with PODs of 0.17 and 1.27 mg/kg bw-day derived from the cancer bioassay data for these tissues in male mice, respectively. Overall, this study supports the involvement of CS in AA-induced mouse carcinogenicity, which is consistent with a recently proposed CS-based MOA in rat thyroid, and with other published reports of aberrant CS in malignant tumors in rodents and humans.

Sex differences and pathology status correlated to the toxicity of some common carcinogens in experimental skin carcinoma

The increased susceptibility of men as compared to women to develop different types of cancer, including skin cancer, is well known; however, the mechanisms involved in this process are still a matter of debate. This study aimed to obtain animal models of photo-chemically-induced skin carcinogenesis by exposure to ultraviolet radiation B (UVB) coupled with topical applications of a tumor initiator (7,12-dimethylbenz(a)anthracene, DMBA) and a tumor promoter (12-O-tetradecanoylphorbol-13-acetate, TPA) in order to characterize the gender disparities regarding the skin lesions developed by the female and male SKH-1 hairless mice included in this study. Histopathological analysis confirmed the presence of malignant lesions in both cases, in female and male mice, following chronic exposure (24 weeks) to the noxious effects of the carcinogens applied, whereas the tumors in male mice had a more severe histological grade. In addition, tumor incidence, size and multiplicity were higher in male mice than in female mice.

Environmental chemical exposure may contribute to uterine cancer development: studies with tetrabromobisphenol A.

Tetrabromobisphenol A (TBBPA), a widely used flame retardant, caused uterine tumors in rats. In this study, TBBPA was administered to male and female Wistar Han rats and B6C3F1/N mice by oral gavage in corn oil for 2 years at doses up to 1,000 mg/kg. TBBPA induced uterine epithelial tumors including adenomas, adenocarcinomas, and malignant mixed Müllerian tumors (MMMTs). In addition, endometrial epithelial atypical hyperplasia occurred in TBBPA-treated rats. Also found to be related to TBBPA treatment, but at lower incidence and at a lower statistical significance, were testicular tumors in rats, and hepatic tumors, hemangiosarcomas (all organs), and intestinal tumors in male mice. It is hypothesized that the TBBPA uterine tumor carcinogenic mechanisms involve altered estrogen levels and/or oxidative damage. TBBPA treatment may affect hydroxysteroid-dehydrogenase-17β (HSD17β) and/or sulfotransferases, enzymes involved in estrogen homeostasis. Metabolism of TBBPA may also result in the formation of free radicals. The finding of TBBPA-mediated uterine cancer in rats is of concern because TBBPA exposure is widespread and endometrial tumors are a common malignancy in women. Further work is needed to understand TBBPA cancer mechanisms.

Pyrogallol-associated dermal toxicity and carcinogenicity in F344/N rats and B6C3F1/N mice

Pyrogallol (CAS No. 87-66-1), a benzenetriol used historically as a hair dye and currently in a number of industrial applications, was nominated to the National Toxicology Program (NTP) for testing based on the lack of toxicity and carcinogenicity data. Three-month and two-year toxicity studies to determine the toxicity and carcinogenicity of pyrogallol when applied to naïve skin (i.e. dermal administration) were conducted in both sexes of F344/N rats and B6C3F1/N mice. In the three-month studies, adult rodents were administered pyrogallol in 95% ethanol five days per week for 3 months at doses of up to 150 mg/kg body weight (rats) or 600 mg/kg (mice). Based on the subchronic studies, the doses for the two-year studies in rats and mice were 5, 20 and 75 mg/kg of pyrogallol. All mice and most rats survived until the end of the three-month study and body weights were comparable to controls. During the two-year study, survival of dosed rats and male mice was comparable to controls; however survival of 75 mg/kg female mice significantly decreased compared to controls. The incidences of microscopic non-neoplastic lesions at the site of application were significantly higher in all dosed groups of rats and mice and in both the 3-months and two-year studies. In the two-year study, hyperplasia, hyperkeratosis and inflammation tended to be more severe in mice than in rats, and in the mice they tended to be more severe in females than in males. The incidence of squamous cell carcinoma at the site of application (SOA) in 75 mg/kg female mice and SOA squamous cell papillomas in 75 mg/kg male mice were greater than controls. Pyrogallol was carcinogenic in female mice and may have caused tumors in male mice.

Investigating the Potential for Toxicity from Long-Term Use of the Herbal Products, Goldenseal and Milk Thistle

Two-year toxicity studies were conducted on the widely used herbal products, goldenseal and milk thistle, in male and female F344/N rats and B6C3F1 mice. With goldenseal root powder, the primary finding was an increase in liver tumors in rats and mice, and with milk thistle extract, a decrease in spontaneous background tumors including mammary gland tumors in female rats and liver tumors in male mice. Increased tumorigenicity in rodents exposed to goldenseal root powder may be due in part to the topoisomerase inhibition properties of berberine, a major alkaloid constituent in goldenseal, or its metabolite, berberrubine. In the clinic, use of topoisomerase-inhibiting agents has been associated with secondary tumor formation and inhibition in DNA repair processes. In contrast, the radical-scavenging and antioxidant properties of silibinin and other flavonolignans in milk thistle extract may have contributed to the decrease in background tumors in rodents in the present studies. The fate of the active constituents of goldenseal and milk thistle is similar in humans and rodents; therefore, the modes of action may translate across species. Further studies are needed to extrapolate the findings to humans.

Potency of Andrographolide as an Antitumor Compound in BHC-Induced Liver Damage

The present investigation relates to the influence of andrographolide, an active compound of Andrographis paniculata Nees. It reverses an experimental liver carcinogenic condition of mice to normal and might be a potential therapeutic/preventive agent for human liver cancer. A. paniculata (Kalmegh) is extensively used in the Indian traditional system of medicine as a hepatoprotective and hepatostimulative agent and has been reported to have protective effect against different hepatotoxins. Histomorphological, ultrastructural, and biochemical studies were performed for the effect of the andrographolide on control mice, mice treated with hexachlorocyclohexane (BHC) only and BHC + andrographolide. Enzymes for liver function tests were analyzed by spectrophotometric method. The BHC experimental model forms an irreversible liver tumor in male mice. The histological and ultrastructural changes observed in andrographolide supplementation emphasize the recovery of the damaged liver. This recovery was also reflected in the neoplastic nodule formation. The activity of phosphorylase and glucose-6-phosphatase in the liver of the andrographolide-supplemented group suggests improved glycogenolysis in liver. Serum glutamate pyruvate transaminase, serum glutamate oxalate transaminase, alkaline phosphatase, acid phosphatase, and gamma-glutamyl transpeptidase showed a significant decrease in andrographolide-supplemented animals as compared with BHC-treated animals, suggesting regenerative effects elicited by andrographolide. The study indicates that the regenerative capability elicited by andrographolide is possibly due to its ability to reactivate liver function enzymes that catalyze the reaction of several biochemical and synthetic processes and that it may be useful for severe liver damage conditions.

Impact of life stage and duration of exposure on arsenic-induced proliferative lesions and neoplasia in C3H mice

Epidemiological studies suggest that chronic exposure to inorganic arsenic is associated with cancer of the skin, urinary bladder and lung as well as the kidney and liver. Previous experimental studies have demonstrated increased incidence of liver, lung, ovary, and uterine tumors in mice exposed to 85 ppm (∼8 mg/kg) inorganic arsenic during gestation. To further characterize age susceptibility to arsenic carcinogenesis we administered 85 ppm inorganic arsenic in drinking water to C3H mice during gestation, prior to pubescence and post-pubescence to compare proliferative lesion and tumor outcomes over a one-year exposure period. Inorganic arsenic significantly increased the incidence of hyperplasia in urinary bladder (48%) and oviduct (36%) in female mice exposed prior to pubescence (beginning on postnatal day 21 and extending through one year) compared to control mice (19 and 5%, respectively). Arsenic also increased the incidence of hyperplasia in urinary bladder (28%) of female mice continuously exposed to arsenic (beginning on gestation day 8 and extending though one year) compared to gestation only exposed mice (0%). In contrast, inorganic arsenic significantly decreased the incidence of tumors in liver (0%) and adrenal glands (0%) of male mice continuously exposed from gestation through one year, as compared to levels in control (30 and 65%, respectively) and gestation only (33 and 55%, respectively) exposed mice. Together, these results suggest that continuous inorganic arsenic exposure at 85 ppm from gestation through one year increases the incidence and severity of urogenital proliferative lesions in female mice and decreases the incidence of liver and adrenal tumors in male mice. The paradoxical nature of these effects may be related to altered lipid metabolism, the effective dose in each target organ, and/or the shorter one-year observational period.

Hepatoprotective Effect of Andrographolide Against Hexachlorocyclohexane-Induced Oxidative Injury

Many plant products are known to exert antioxidative effects by quenching various free radicals and singlet molecular oxygen. Andrographis paniculata (Kalmegh) is used extensively in the Indian traditional system of medicine as a hepatoprotective and hepatostimulative agent and has been reported to have antioxidant effects against different hepatotoxins. The present study aims to analyze antioxidant properties of an active component, andrographolide (ANDLE), extracted from A paniculata. This study investigates the effect of andrographolide on the hepatocellular antioxidant defense system and lipid peroxidation of control mice, mice treated with hexachlorocyclohexane (BHC) only, and andrographolide + BHC. Glutathione (GSH), glutathione-s-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GSH-Px), gamma-glutamyl transpeptidase (gamma-GTP), superoxide dismutase (SOD), catalase (CAT), and lipid peroxidation (LPO) are studied by spectrophotometric methods. The BHC experimental model forms an irreversible liver tumor in male mice. The activities of GSH, GR, GSH-Px, SOD, and CAT show significant (P <or= .05) increases, while gamma-GTP and GST show significant decreases (P <or= .05) in andrographolide-supplemented mice as compared with BHC-treated mice. This study indicates that the antioxidant effect of andrographolide could be due to its ability to activate antioxidant enzymes that catalyze the reaction of oxidants and are effective in severe liver damage.

Androgen receptor targets NFκB and TSP1 to suppress prostate tumor growth in vivo

The androgen role in the maintenance of prostate epithelium is subject to conflicting opinions. While androgen ablation drives the regression of normal and cancerous prostate, testosterone may cause both proliferation and apoptosis. Several investigators note decreased proliferation and stronger response to chemotherapy of the prostate cancer cells stably expressing androgen receptor (AR), however no mechanistic explanation was offered. In this paper we demonstrate in vivo anti-tumor effect of the AR on prostate cancer growth and identify its molecular mediators. We analyzed the effect of AR on the tumorigenicity of prostate cancer cells. Unexpectedly, the AR-expressing cells formed tumors in male mice at a much lower rate than the AR-negative controls. Moreover, the AR-expressing tumors showed decreased vascularity and massive apoptosis. AR expression lowered the angiogenic potential of cancer cells, by increasing secretion of an anti-angiogenic protein, thrombospondin-1. AR activation caused a decrease in RelA, a subunit of the pro-survival transcription factor NFkappaB, reduced its nuclear localization and transcriptional activity. This, in turn, diminished the expression of its anti-apoptotic targets, Bcl-2 and IL-6. Increased apoptosis within AR-expressing tumors was likely due to the NFkappaB suppression, since it was restricted to the cells lacking nuclear (active) NFkappaB. Thus we for the first time identified combined decrease of NFkappaB and increased TSP1 as molecular events underlying the AR anti-tumor activity in vivo. Our data indicate that intermittent androgen ablation is preferable to continuous withdrawal, a standard treatment for early-stage prostate cancer. (c) 2007 Wiley-Liss, Inc.

Gender Differences in UVB-Induced Skin Carcinogenesis, Inflammation, and DNA Damage

The American Cancer Society reports the incidence of squamous cell carcinoma in males to be thrice the incidence in females. This increased squamous cell carcinoma incidence has been attributed to men accumulating more sun exposure and using less sun protection than women. To date, there have been no controlled studies examining the effect of gender on skin tumor development following equal doses of UVB. Gender differences in UVB-induced skin carcinogenesis were examined using the Skh-1 mouse model. After chronic exposure to equal doses of UVB, male mice developed tumors earlier and had more tumors than female mice; tumors in male mice tended to be larger, and the total tumor burden was greater than in females. In addition, tumors in males were of more advanced histologic grade compared with those of female mice. To evaluate the contribution of differences in inflammation and DNA damage to differences in skin carcinogenesis, male and female Skh-1 mice were exposed once to 2,240 J/m(2) UVB and examined 48 h after exposure. Surprisingly, male mice developed less of an inflammatory response, as determined by skin fold thickness and myeloperoxidase activity, compared with females. Interestingly, male mice showed more cutaneous oxidative DNA damage than the females and lower antioxidant levels. These results show a gender bias in skin carcinogenesis and suggest that the gender difference in tumor development is more influenced by the extent of oxidative DNA damage and antioxidant capacities than by inflammatory response.