Chemical carcinogenesis

Temozolomide alleviates breast carcinoma via the inhibition of EGFR/ERK/ MMP-1 pathway with induction of apoptotic events

PURPOSE

To evaluate the chemotherapeutic activity of temozolomide counter to mammary carcinoma.

METHODS

In-vitro anticancer activity has been conducted on MCF7 cells, and mammary carcinoma has been induced in Wistar rats by introduction of 7, 12-Dimethylbenz(a)anthracene (DMBA), which was sustained for 24 weeks. Histopathology, immunohistochemistry, cell proliferation study and apoptosis assay via TUNEL method was conducted to evaluate an antineoplastic activity of temozolomide in rat breast tissue.

RESULTS

IC50 value of temozolomide in MCF7 cell has been obtained as 103 μM, which demonstrated an initiation of apoptosis. The temozolomide treatment facilitated cell cycle arrest in G2/M and S phase dose dependently. The treatment with temozolomide suggested decrease of the hyperplastic abrasions and renovation of the typical histological features of mammary tissue. Moreover, temozolomide therapy caused the downregulation of epidermal growth factor receptor, extracellular signal-regulated kinase, and metalloproteinase-1 expression and upstream of p53 and caspase-3 proliferation to indicate an initiation of apoptotic events.

CONCLUSIONS

The occurrence of mammary carcinoma has been significantly decreased by activation of apoptotic pathway and abrogation of cellular propagation that allowable for developing a suitable mechanistic pathway of temozolomide in order to facilitate chemotherapeutic approach.

Current views on in vivo models for breast cancer research and related drug development

INTRODUCTION

Animal models play a crucial role in breast cancer research, in particular mice and rats, who develop mammary tumors that closely resemble their human counterparts. These models allow the study of mechanisms behind breast carcinogenesis, as well as the efficacy and safety of new, and potentially more effective and advantageous therapeutic approaches. Understanding the advantages and disadvantages of each model is crucial to select the most appropriate one for the research purpose.

AREA COVERED

This review provides a concise overview of the animal models available for breast cancer research, discussing the advantages and disadvantages of each one for searching new and more effective approaches to treatments for this type of cancer.

EXPERT OPINION

Rodent models provide valuable information on the genetic alterations of the disease, the tumor microenvironment, and allow the evaluation of the efficacy of chemotherapeutic agents. However, in vivo models have limitations, and one of them is the fact that they do not fully mimic human diseases. Choosing the most suitable model for the study purpose is crucial for the development of new therapeutic agents that provide better care for breast cancer patients.

Duality of the SVIL expression in bladder cancer and its correlation with immune infiltration

SVIL is a member of the villin/gelsolin superfamily and is responsible for encoding supervillin. It has been reported to be closely related to the occurrence and development of various tumors. However, the mechanism of SVIL in bladder cancer has not been reported yet. In this research, we evaluated the relationship between SVIL expression and bladder cancer in public dataset and examined the expression of SVIL in bladder cancer cell lines, tissue microarrays and patients in our cohort. Our work determined that the expression of SVIL in bladder cancer tissue was significantly lower than that in normal tissue. However, in bladder cancer tissues, the high expression of SVIL is significantly associated with poor prognosis. This kind of duality is very novel and has great research value. The expression level of SVIL can well predict the survival time of bladder cancer patients, and is an independent risk factor of bladder cancer patients. The expression of SVIL is also closely related to the immune tumor microenvironment of bladder cancer. Our research provides a basis for personalized therapeutic targets for bladder cancer.

Monitoring residues of pesticides in food in Brazil: A multiscale analysis of the main contaminants, dietary cancer risk estimative and mechanisms associated

Introduction

Pesticides pose a risk for cancer development and progression. People are continuously exposed to such substances by several routes, including daily intake of contaminated food and water, especially in countries that are highly pesticide consumers and have very permissive legislation about pesticide contamination as Brazil. This work investigated the relationship among pesticides, food contamination, and dietary cancer risk.

Methods

Analyzed two social reports from the Brazilian Government: the Program for Analysis of Residues of Pesticides in Food (PARA) and The National Program for Control of Waste and Contaminants (PNCRC).

Results and discussion

First, we characterized the main pesticide residues detected over the maximum limits allowed by legislation or those prohibited for use in food samples analyzed across the country. Based on this list, we estimated the dietary cancer risks for some of the selected pesticides. Finally, we searched for data about dietary cancer risks and carcinogenic mechanisms of each pesticide. We also provided a critical analysis concerning the pesticide scenario in Brazil, aiming to discuss the food contamination levels observed from a geographical, political, and public health perspective. Exposures to pesticides in Brazil violate a range of human rights when food and water for human consumption are contaminated.

Is GRP78 (Glucose-regulated protein 78) a prognostic biomarker in differents types of cancer? A systematic review and meta-analysis

GRP78 is a chaperone with anti-apoptotic function associated with aggressive tumors. This systematic review aimed to evaluate GRP78 expression in cancer and its relation to prognosis outcomes. This review was conducted in different databases searching for human cancer studies assessing GRP78 immunohistochemical levels on tissue samples. A total of 98 manuscripts were included. In 62% of the studies, GRP78 was associated with a worse prognosis. A meta-analysis included 29 studies that detected a significantly higher expression of GRP78 in cancer tissues (RR= 2.35, 95% CI 1.75-3.15) compared to control. A meta-analysis of 3 and 5-years Overall Survival revealed an increased risk of death for tumors with high expression of GRP78 (RR=1.36, 95%CI 1.16-1,59, I² = 57%) and (RR=1.65, 95%CI 1.22-2.21, I² =64%), respectively. GRP78 is an important prognostic biomarker for different types of cancer and a promising therapeutic target.

Contribution of common plastic-related endocrine disruptors to epithelial-mesenchymal transition (EMT) and tumor progression

Many chemicals, including many endocrine disruptors (EDCs) are known to leach out from various plastic consumer products and waste, and are widespread in the environment. EDCs are a large group of contaminants that can interfere with hormonal metabolism or function. In addition, there are in the literature implications of contribution by EDCs in tumor progression, the last stage of carcinogenesis driven by cells with a metastatic phenotype. The process of epithelial cells losing their apical-basal polarity and cell-to-cell contacts, and acquiring migration and invasive properties typical of mesenchymal cells is called epithelial-mesenchymal transition (EMT). It is essential for tumor progression. In human cells, plastic-related EDCs, (phthalates, bisphenol A, and the alkylphenols: nonylphenol and octylphenol) reduce epithelial E-cadherin, and increase mesenchymal N-cadherin and extracellular matrix metalloproteinases. These changes are hallmarks of EMT. In xenograft mouse studies, EDCs increase migration of cells and metastatic growth in distant tissues. Their contribution to EMT and tumor progression, the topic of this review, is important from public health perspective, because of the ubiquitous exposure to these EDCs. In this mini-review we also discuss molecular mechanisms associated with EDC-induced EMT and tumor progression.

Analysis of the Whole-Genome Sequences from an Equus Parent-Offspring Trio Provides Insight into the Genomic Incompatibilities in the Hybrid Mule

Interspecific hybridization often shows negative effects on hybrids. However, only a few multicellular species, limited to a handful of plants and animals, have shown partial genetic mechanisms by which hybridization leads to low fitness in hybrids. Here, to explore the outcome of combining the two genomes of a horse and donkey, we analyzed the whole-genome sequences from an Equus parent-offspring trio using Illumina platforms. We generated 41.39× and 46.21× coverage sequences for the horse and mule, respectively. For the donkey, a 40.38× coverage sequence was generated and stored in our laboratory. Approximately 24.86 million alleles were discovered that varied from the reference genome. Single nucleotide polymorphisms were used as polymorphic markers for assigning alleles to their parental genomic inheritance. We identified 25,703 Mendelian inheritance error single nucleotide polymorphisms in the mule genome that were not inherited from the parents through Mendelian inheritance. A total of 555 de novo single nucleotide polymorphisms were also identified. The rate of de novo single nucleotide polymorphisms was 2.21 × 10^-7 in the mule from the Equus parent-offspring trio. This rate is obviously higher than the natural mutation rate for Equus, which is also consistent with the previous hypothesis that interracial crosses may have a high mutation rate. The genes associated with these single nucleotide polymorphisms are mainly involved in immune processes, DNA repair, and cancer processes. The results of the analysis of three genomes from an Equus parent-offspring trio improved our knowledge of the consequences of the integration of parental genomes in mules.

Enriched Riceberry Bran Oil Exerts Chemopreventive Properties through Anti-Inflammation and Alteration of Gut Microbiota in Carcinogen-Induced Liver and Colon Carcinogenesis in Rats

Riceberry has recently been acknowledged for its beneficial pharmacological effects. Riceberry bran oil (RBBO) exhibited anti-proliferation activity in various cancer cell lines. However, animal studies of RBBO on anti-carcinogenicity and its molecular inhibitory mechanism have been limited. This study purposed to investigate the chemopreventive effects of RBBO on the carcinogen-induced liver and colorectal carcinogenesis in rats. Rats were injected with diethylnitrosamine (DEN) and 1,2-dimethylhydrazine (DMH) and further orally administered with RBBO equivalent to 100 mg/kg body weight of γ-oryzanol 5 days/week for 10 weeks. RBBO administration suppressed preneoplastic lesions including hepatic glutathione S-transferase placental form positive foci and colorectal aberrant crypt foci. Accordingly, RBBO induced hepatocellular and colorectal cell apoptosis and reduced pro-inflammatory cytokine expression. Interestingly, RBBO effectively promoted the alteration of gut microbiota in DEN- and DMH-induced rats, as has been shown in the elevated Firmicutes/Bacteroidetes ratio. This outcome was consistent with an increase in butyrate in the feces of carcinogen-induced rats. The increase in butyrate reflects the chemopreventive properties of RBBO through the mechanisms of its anti-inflammatory properties and cell apoptosis induction in preneoplastic cells. This would indicate that RBBO containing γ-oryzanol, phytosterols, and tocols holds significant potential in the prevention of cancer.

Mouse Models for Immune Checkpoint Blockade Therapeutic Research in Oral Cancer

The most prevalent oral cancer globally is oral squamous cell carcinoma (OSCC). The invasion of adjacent bones and the metastasis to regional lymph nodes often lead to poor prognoses and shortened survival times in patients with OSCC. Encouraging immunotherapeutic responses have been seen with immune checkpoint inhibitors (ICIs); however, these positive responses to monotherapy have been limited to a small subset of patients. Therefore, it is urgent that further investigations into optimizing immunotherapies are conducted. Areas of research include identifying novel immune checkpoints and targets and tailoring treatment programs to meet the needs of individual patients. Furthermore, the advancement of combination therapies against OSCC is also critical. Thus, additional studies are needed to ensure clinical trials are successful. Mice models are advantageous in immunotherapy research with several advantages, such as relatively low costs and high tumor growth success rate. This review paper divided methods for establishing OSCC mouse models into four categories: syngeneic tumor models, chemical carcinogen induction, genetically engineered mouse, and humanized mouse. Each method has advantages and disadvantages that influence its application in OSCC research. This review comprehensively surveys the literature and summarizes the current mouse models used in immunotherapy, their advantages and disadvantages, and details relating to the cell lines for oral cancer growth. This review aims to present evidence and considerations for choosing a suitable model establishment method to investigate the early diagnosis, clinical treatment, and related pathogenesis of OSCC.

Transcriptome analysis of human cholangiocytes exposed to carcinogenic 1,2-dichloropropane in the presence of macrophages in vitro

1,2-Dichloropropane (1,2-DCP), a synthetic organic solvent, has been implicated in causality of cholangiocarcinoma (bile duct cancer). 1,2-DCP-induced occupational cholangiocarcinoma show a different carcinogenic process compared to common cholangiocarcinoma, but its mechanism remains elusive. We reported previously that exposure of MMNK-1 cholangiocytes co-cultured with THP-1 macrophages, but not monocultured MMNK-1 cholangiocytes, to 1,2-DCP induced activation-induced cytidine deaminase (AID) expression, DNA damage and ROS production. The aim of this study was to identify relevant biological processes or target genes expressed in response to 1,2-DCP, using an in vitro system where cholangiocytes are co-cultured with macrophages. The co-cultured cells were exposed to 1,2-DCP at 0, 0.1 or 0.4 mM for 24 h, and then the cell lysates were assessed by transcriptome analysis. 1,2-DCP upregulated the expression of base excision repair genes in MMNK-1 cholangiocytes in the co-cultures, whereas it upregulated the expression of cell cycle-related genes in THP-1 macrophages. Activation of the base excision repair pathway might result from the previously observed DNA damage in MMNK-1 cholangiocytes co-cultured with THP-1 macrophages, although involvement of other mechanisms such as DNA replication, cell death or other types of DNA repair was not disproved. Cross talk interactions between cholangiocytes and macrophages leading to DNA damage in the cholangiocytes should be explored.

Periodontal Pathogens: A Crucial Link Between Periodontal Diseases and Oral Cancer

Emerging evidence shows a striking link between periodontal diseases and various human cancers including oral cancer. And periodontal pathogens, leading to periodontal diseases development, may serve a crucial role in oral cancer. This review elucidated the molecular mechanisms of periodontal pathogens in oral cancer. The pathogens directly engage in their own unique molecular dialogue with the host epithelium to acquire cancer phenotypes, and indirectly induce a proinflammatory environment and carcinogenic substance in favor of cancer development. And functional, rather than compositional, properties of oral microbial community correlated with cancer development are discussed. The effect of periodontal pathogens on periodontal diseases and oral cancer will further detail the pathogenesis of oral cancer and intensify the need of maintaining oral hygiene for the prevention of oral diseases including oral cancer.

Alternariol ameliorates lung carcinoma via reprogramming cytokine signaling associated with PI3K/Akt cascade in vitro and in vivo

Objectives

The lung cancer is most frequently diagnosed cancer incidence worldwide. A large number of populations are heavily affected to this every year with poor prognosis.

Methods

Our study investigated the anticancer effect of alternariol, a secondary metabolite, on A549 lung cancer cell line and benzo-α-pyrene induced lung carcinoma model on balb/c mice. The cytotoxicity assay, DAPI staining and the flow cytometry was performed to assess the anticancer efficacy of alternariol in A549 lung cancer cell. For in vivo study the toxicity study was performed. The lung cancer was developed in the animals via intraperitoneal administration of benzo-α-pyrene and subsequently 2 weeks later alternariol treatment was carried out for 24 weeks. The chemotherapeutic effect of alternariol was assessed through histopathological analysis, followed by immunohistochemistry and in vivo antioxidant study.

Results

The in vitro data suggested a significant percentage of early and late apoptotic events in A549 cells with G0/G1 phase arrest which ultimately caused apoptosis followed by alternariol therapy. The in vivo study showed that alternariol therapy decreased the pulmonary fibrosis and formation of granuloma in lung tissue and restored the normal histopathological characteristics of lung. Furthermore, alternariol treatment downregulated the expression of PI3K, Akt and inflammatory mediators such as IL-6, TNF-α and increased the expression of apoptotic markers, p53.

Conclusion

In conclusion, the treatment with alternariol effectively decreased the progression of lung cancer through the inhibition of carcinogenic markers by reprogramming the p53/PI3K/Akt pathway and IL-6/TNF-α mediated cytokine signaling in mice.

Release of particulate matter from nano-enabled building materials (NEBMs) across their lifecycle: Potential occupational health and safety implications

The present study investigates potential nanomaterial releases and occupational health risks across the lifecycle of nano-enabled building materials (NEBMs), namely, insulations and coatings. We utilized real-world degradation scenarios of a) sanding (mechanical), b) incineration (thermal), and c) accelerated UV-aging (environmental) followed by incineration. Extensive physicochemical characterization of the released lifecycle particulate matter (LCPM) was performed. The LCPM2.5 aerosol size fraction was used to assess the acute biological, cytotoxic and inflammatory effects on Calu-3 human lung epithelial cells. RNA-Seq analysis of exposed cells was performed to assess potential for systemic disease. Findings indicated that release dynamics and characteristics of LCPM depended on both the NEBM composition and the degradation scenario(s). Incineration emitted a much higher nanoparticle number concentration than sanding (nearly 4 orders of magnitude), which did not change with prior UV-aging. Released nanofillers during sanding were largely part of the matrix fragments, whereas those during incineration were likely physicochemically transformed. The LCPM from incineration showed higher bioactivity and inflammogenicity compared to sanding or sequential UV-aging and incineration, and more so when metallic nanofillers were present (such as Fe2O3). Overall, the study highlights the need for considering real-world exposure and toxicological data across the NEBM lifecycle to perform adequate risk assessments and to ensure workplace health and safety.

Alternariol alleviates breast carcinoma by inhibiting cellular proliferation correlated with increased apoptotic events in rats

The breast cancer is most frequently diagnosed cancer in the women worldwide. Our study investigated the anticancer effect of alternariol, a secondary metabolite originated from endophytic fungi, against DMBA induced breast carcinoma on Wistar rats. The toxicity study investigated the LD50 and the subsequent doses of alternariol for the carcinogenic study. The breast cancer was developed in rats via induction of DMBA (5 mg/kg, i.v.) and the carcinogenic study was continued for 24 weeks. The induction of breast cancer and the chemotherapeutic effect of alternariol were assessed through histopathological analysis of rat mammary tissue, followed by immunohistochemical analysis, cell proliferation assay and apoptosis assay by TUNEL method. The result showed that alternariol therapy decreased the hyperplastic lesions of mammary tissue and restored the normal histopathological characteristics of breast tissue. Furthermore, alternariol treatment downregulated the expression of carcinogenic markers such as PI3K and Akt increased the expression of apoptotic markers including p53, caspase-3 and Bax. Alternariol therapy also decreased the cellular proliferation and enhanced the apoptotic events. In conclusion, the breast cancer progression was significantly reduced via induction of apoptotic events and inhibition of cell propagation which allowed constructing of suitable mechanism for alternariol mediated chemotherapeutic approach.

Potential lncRNA Biomarkers for HBV-Related Hepatocellular Carcinoma Diagnosis Revealed by Analysis on Coexpression Network

Background

Increasing evidence demonstrated that long noncoding RNA (lncRNA) could affect inflammatory tumor immune microenvironment by modulating gene expression and could be used as a biomarker for HBC-related hepatocellular carcinoma (HCC) but still needs further research. The aim of the present study was to determine an lncRNA signature for the diagnosis of HBV-related HCC.

Methods

HBV-related HCC expression profiles (GSE55092, GSE19665, and GSE84402) were abstracted from the GEO (Gene Expression Omnibus) data resource, and R package limma and RobustRankAggreg were employed to identify common differentially expressed genes (DEGs). Using machine learning, optimal diagnostic lncRNA molecular markers for HBV-related HCC were identified. The expression of candidate lncRNAs was cross-validated in GSE121248, and an ROC (receiver operating characteristic) curve of lncRNA biomarkers was carried out. Additionally, a coexpression network and functional annotation was built, after which a PPI (protein-protein interaction) network along with module analysis were conducted with the Cytoscape open source software.

Result

A total of 38 DElncRNAs and 543 DEmRNAs were identified with a fold change larger than 2.0 and a P value < 0.05. By machine learning, AL356056.2, AL445524.1, TRIM52-AS1, AC093642.1, EHMT2-AS1, AC003991.1, AC008040.1, LINC00844, and LINC01018 were screened out as optional diagnostic lncRNA biosignatures for HBV-related HCC. The AUC (areas under the curve) of the SVM (support vector machine) model and random forest model were 0.957 and 0.904, respectively, and the specificity and sensitivity were 95.7 and 100% and 94.3 and 86.5%, respectively. The results of functional enrichment analysis showed that the integrated coexpressed DEmRNAs shared common cascades in the p53 signaling pathway, retinol metabolism, PI3K-Akt signaling cascade, and chemical carcinogenesis. The integrated DEmRNA PPI network complex was found to be comprised of 87 nodes, and two vital modules with a high degree were selected with the MCODE app.

Conclusion

The present study identified nine potential diagnostic biomarkers for HBV-related HCC, all of which could potentially modulated gene expression related to inflammatory conditions in the tumor immune microenvironment. The functional annotation of the target DEmRNAs yielded novel evidence in evaluating the precise functions of lncRNA in HBV-related HCC.

Alcohol Drinking Pattern and Risk of Head and Neck Cancer: A Nationwide Cohort Study

Alcohol consumption is a major risk factor for head and neck cancer (HNC), yet little data exist examining drinking patterns and HNC risk. In this population-based, retrospective cohort study, 11,737,467 subjects were recruited from the Korean National Health Insurance Service database. The risks of overall HNC and HNC subtypes according to average alcohol consumption, drinking frequency, and daily amount were examined using Cox proportional hazard models. Over the median follow-up of 6.4 years, 15,832 HNC cases were identified. HNC risk linearly increased with drinking frequency (p-trend < 0.01; adjusted hazard ratio [aHR] 1.55, 95% confidence interval [CI] 1.45–1.67 in subjects who drank 7 days/week). HNC risk also increased according to daily amount of alcohol consumption (p-trend < 0.01), but plateaued from 5–7 units/occasion (aHR 1.25, 95% CI 1.19–1.31) to >14 units/occasion (aHR 1.26, 95% CI 1.13–1.40). When stratified by average alcohol consumption, drinking frequency, but not daily amount, showed a linear relationship with HNC risk in moderate and heavy drinkers. When comparing the HNC subtypes, similar tendencies were observed in cancers of the oral cavity, pharynx, and larynx, but not in the salivary gland. In conclusion, drinking frequency is a stronger risk factor for HNC, especially for cancer of the oral cavity, pharynx, and larynx, than the daily amount of alcohol consumption.

Brigatinib loaded poly(d,l-lactide-co-glycolide) nanoparticles for improved anti-tumoral activity against non-small cell lung cancer cell lines

OBJECTIVE

The aim of the current investigation was to develop poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles (NPs) to sustain the brigatinib (BTB) release for prolong time period and to examine the antitumor effect of the optimized NPs.

SIGNIFICANCE

Optimized PLGA-based NPs of BTB could be potentially used as a promising nanocarrier for the treatment of non-small cell lung cancer.

METHODS

BTB-loaded NPs were fabricated with core-shell of PLGA by solvent evaporation technique using different proportions of PLGA polymer and poly-vinyl alcohol (PVA) stabilizer. The prepared NPs were evaluated for particle characterizations; size, polydispersity index (PDI), zeta-potential, entrapment efficiency (EE), and drug loading (DL), Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and X-ray diffraction studies. The optimized NPs (BN5) were further evaluated for morphology, stability, and cytotoxicity studies against A549 cell-lines.

RESULTS

Among the nine different NPs formulae (BN1-BN9), BN5 was optimized with composition of BTB (30 mg), PLGA (75 mg), PVA (0.55% w/v), represents an average particle size of (267.1 ± 1.01 nm), PDI (0.101 ± 0.007), and zeta potential (-42.1 ± 0.75 mV), high EE (66.83 ± 0.06%), and DL (6.17 ± 0.69%). SEM image of selected NPs was spherical with smooth surface. In vitro drug release profile in phosphate buffers (pH 5 and pH 7.4) showed a biphasic release with initial burst phase followed by sustained release for prolong time. Furthermore, optimized NPs (BN5) exhibited excellent cytotoxic activity against A549 cell-lines with IC₅₀ value of 5.25 ± 0.23 µg/mL.

CONCLUSION

The overall results suggest that BTB-loaded PLGA NPs could be a potential nanocarrier for lung cancer treatment.

Natural Products: Implication in Cancer Prevention and Treatment through Modulating Various Biological Activities

Cancer is one of the most leading causes of death worldwide. It is one of the primary global diseases that cause morbidity and mortality in millions of people. It is usually caused by different carcinogenic agents that damage the genetic material and alter the cell signaling pathways. Carcinogens are classified into two groups as genotoxic and non-genotoxic agents. Genotoxic carcinogens are capable of directly altering the genetic material, while the non-genotoxic carcinogens are capable of producing cancer by some secondary mechanisms not related to direct gene damage. There is undoubtedly the greatest need to utilize some novel natural products as anticancer agents, as these are within reach everywhere. Interventions by some natural products aimed at decreasing the levels and conditions of these risk factors can reduce the frequency of cancer incidences. Cancer is conventionally treated by surgery, radiation therapy and chemotherapy, but such treatments may be fast-acting and causes adverse effects on normal tissues. Alternative and innovative methods of cancer treatment with the least side effects and improved efficiency are being encouraged. In this review, we discuss the different risk factors of cancer development, conventional and innovative strategies of its management and provide a brief review of the most recognized natural products used as anticancer agents globally.

Role of Macrophages in Cytotoxicity, Reactive Oxygen Species Production and DNA Damage in 1,2-Dichloropropane-Exposed Human Cholangiocytes In Vitro

1,2-Dichloropropane (1,2-DCP), a synthetic chlorinated organic compound, was extensively used in the past in offset color proof-printing. In 2014, the International Agency for Research on Cancer (IARC) reclassified 1,2-DCP from its initial Group 3 to Group 1. Prior to the reclassification, cholangiocarcinoma was diagnosed in a group of workers exposed to 1,2 -DCP in an offset color proof-printing company in Japan. In comparison with other forms of cholangiocarcinoma, 1,2-DCP-induced cholangiocarcinoma was of early onset and accompanied by extensive pre-cancerous lesions in large bile ducts. However, the mechanism of 1,2-DCP-induced cholangiocarcinoma is poorly understood. Inflammatory cell proliferation was observed in various sites of the bile duct in the noncancerous hepatic tissues of the 1,2-DCP-induced cholangiocarcinoma. The aim of this study was to enhance our understanding of the mechanism of 1,2-DCP-related cholangiocarcinogenesis. We applied an in vitro system to investigate the effects of 1,2-DCP, using MMNK-1 cholangiocytes cultured alone or with THP-1 macrophages. The cultured cells were exposed to 1,2-DCP at 0, 0.1, 0.2, 0.4, and 0.8 mM for 24 h, and then assessed for cell proliferation, cell cytotoxicity, DNA damage, and ROS production. Exposure to 1,2-DCP increased proliferation of MMNK-1 cholangiocytes cultured alone, but not those cultured with macrophages. 1,2-DCP also increased LDH cytotoxicity, DNA damage, and ROS production in MMNK-1 cholangiocytes co-cultured with macrophages but not those cultured alone. 1,2-DCP increased TNFα and IL-1β protein expression in macrophages. The results highlight the role of macrophages in enhancing the effects of 1,2-DCP on cytotoxicity, ROS production, and DNA damage in cholangiocytes.

β-Hexachlorocyclohexane Drives Carcinogenesis in the Human Normal Bronchial Epithelium Cell Line BEAS-2B

Organochlorine pesticides constitute the majority of the total environmental pollutants, and a wide range of compounds have been found to be carcinogenic to humans. Among all, growing interest has been focused on β-hexachlorocyclohexane (β-HCH), virtually the most hazardous and, at the same time, the most poorly investigated member of the hexachlorocyclohexane family. Considering the multifaceted biochemical activities of β-HCH, already established in our previous studies, the aim of this work is to assess whether β-HCH could also trigger cellular malignant transformation toward cancer development. For this purpose, experiments were performed on the human normal bronchial epithelium cell line BEAS-2B exposed to 10 µM β-HCH. The obtained results strongly support the carcinogenic potential of β-HCH, which is achieved through both non-genotoxic (activation of oncogenic signaling pathways and proliferative activity) and indirect genotoxic (ROS production and DNA damage) mechanisms that significantly affect cellular macroscopic characteristics and functions such as cell morphology, cell cycle profile, and apoptosis. Taking all these elements into account, the presented study provides important elements to further characterize β-HCH, which appears to be a full-fledged carcinogenic agent.

Selection of safe artemisinin derivatives using a machine learning-based cardiotoxicity platform and in vitro and in vivo validation

The majority of drug candidates fails the approval phase due to unwanted toxicities and side effects. Establishment of an effective toxicity prediction platform is of utmost importance, to increase the efficiency of the drug discovery process. For this purpose, we developed a toxicity prediction platform with machine-learning strategies. Cardiotoxicity prediction was performed by establishing a model with five parameters (arrhythmia, cardiac failure, heart block, hypertension, myocardial infarction) and additional toxicity predictions such as hepatotoxicity, reproductive toxicity, mutagenicity, and tumorigenicity are performed by using Data Warrior and Pro-Tox-II software. As a case study, we selected artemisinin derivatives to evaluate the platform and to provide a list of safe artemisinin derivatives. Artemisinin from Artemisia annua was described first as an anti-malarial compound and later its anticancer properties were discovered. Here, random forest feature selection algorithm was used for the establishment of cardiotoxicity models. High AUC scores above 0.830 were achieved for all five cardiotoxicity indications. Using a chemical library of 374 artemisinin derivatives as a case study, 7 compounds (deoxydihydro-artemisinin, 3-hydroxy-deoxy-dihydroartemisinin, 3-desoxy-dihydroartemisinin, dihydroartemisinin-furano acetate-d3, deoxyartemisinin, artemisinin G, artemisinin B) passed the toxicity filtering process for hepatotoxicity, mutagenicity, tumorigenicity, and reproductive toxicity in addition to cardiotoxicity. Experimental validation with the cardiomyocyte cell line AC16 supported the findings from the in silico cardiotoxicity model predictions. Transcriptomic profiling of AC16 cells upon artemisinin B treatment revealed a similar gene expression profile as that of the control compound, dexrazoxane. In vivo experiments with a Zebrafish model further substantiated the in silico and in vitro data, as only slight cardiotoxicity in picomolar range was observed. In conclusion, our machine-learning approach combined with in vitro and in vivo experimentation represents a suitable method to predict cardiotoxicity of drug candidates.

Formaldehyde exposure and leukemia risk: a comprehensive review and network-based toxicogenomic approach

Formaldehyde is a widely used but highly reactive and toxic chemical. The International Agency for Research on Cancer classifies formaldehyde as a Group 1 carcinogen, based on nasopharyngeal cancer and leukemia studies. However, the correlation between formaldehyde exposure and leukemia incidence is a controversial issue. To understand the association between formaldehyde exposure and leukemia, we explored biological networks based on formaldehyde-related genes retrieved from public and commercial databases. Through the literature-based network approach, we summarized qualitative associations between formaldehyde exposure and leukemia. Our results indicate that oxidative stress-mediated genetic changes induced by formaldehyde could disturb the hematopoietic system, possibly leading to leukemia. Furthermore, we suggested major genes that are thought to be affected by formaldehyde exposure and associated with leukemia development. Our suggestions can be used to complement experimental data for understanding and identifying the leukemogenic mechanism of formaldehyde.

Pro-Tumoral Functions of Autophagy Receptors in the Modulation of Cancer Progression

Cancer progression involves a variety of pro-tumorigenic biological processes including cell proliferation, migration, invasion, and survival. A cellular pathway implicated in these pro-tumorigenic processes is autophagy, a catabolic route used for recycling of cytoplasmic components to generate macromolecular building blocks and energy, under stress conditions, to remove damaged cellular constituents to adapt to changing nutrient conditions and to maintain cellular homeostasis. During autophagy, cells form a double-membrane sequestering a compartment termed the phagophore, which matures into an autophagosome. Following fusion with the lysosome, the cargo is degraded inside the autolysosomes and the resulting macromolecules released back into the cytosol for reuse. Cancer cells use this recycling system during cancer progression, however the key autophagy players involved in this disease is unclear. Accumulative evidences show that autophagy receptors, crucial players for selective autophagy, are overexpressed during cancer progression, yet the mechanisms whereby pro-tumorigenic biological processes are modulated by these receptors remains unknown. In this review, we summarized the most important findings related with the pro-tumorigenic role of autophagy receptors p62/SQSTM1, NBR1, NDP52, and OPTN in cancer progression. In addition, we showed the most relevant cargos degraded by these receptors that have been shown to function as critical regulators of pro-tumorigenic processes. Finally, we discussed the role of autophagy receptors in the context of the cellular pathways implicated in this disease, such as growth factors signaling, oxidative stress response and apoptosis. In summary, we highlight that autophagy receptors should be considered important players of cancer progression, which could offer a niche for the development of novel diagnosis and cancer treatment strategies.

Protective effects of honey and bee venom against lipopolysaccharide and carbon tetrachloride-induced hepatoxicity and lipid peroxidation in rats

In the present study, the protective effects of honey and bee venom (BV) either independently or in combination against lipopolysaccharide (LPS) and carbon tetrachloride (CCl₄)-induced hepatoxicity, lipid peroxidation, and hematological alterations in male albino rats were investigated. In addition, histopathological alterations of hepatic tissues induced by LPS/CCL₄ were recorded. Sixty-four of male albino rats of average weight 120-150 g were included in this study. Rats were divided into eight equal groups of eight. The obtained results demonstrated that treatment with LPS/CCl₄ caused an increase in the levels of alpha-fetoprotein, which was accompanied by changes in the hepatic function biomarkers that characterized by the increased levels of transaminases (AST, ALT). The results showed oxidative stress as assigned by the increase in lipid peroxide. Meantime detraction in the antioxidants, including glutathione peroxidase was observed. Interruptions in biochemical parameters accompanied by disturbances in hematological parameters and liver histopathology were resulted due to exposure to LPS/CCl₄. This study showed the use of honey and BV provided a protective effect on hepatotoxicity induced by LPS/CCl₄. This might have been occurred through the reduction of hepatic transaminases and the "Alpha-fetoprotein" in serum and the equilibration of the antioxidation system, thereby, inhibiting the reactive oxygen species accumulation. Honey and BV administration reestablish disturbed hematological parameters and liver histopathology persuaded by LPS/CCl₄. More interesting, we demonstrated that using a combination of the honey and BV showed promising enhancement in their protective effects over the use of just one of the two reagents.

Withania somnifera (L.) Dunal: A potential therapeutic adjuvant in cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Withania somnifera (L.) Dunal (WS) is one of the moststudied Rasayana botanicals used in Ayurveda practice for its immunomodulatory, anti-aging, adaptogenic, and rejuvenating effects. The botanical is being used for various clinical indications, including cancer. Several studies exploring molecular mechanisms of WS suggest its possible role in improving clinical outcomes in cancer management. Therefore, research on WS may offer new insights in rational development of therapeutic adjuvants for cancer.

AIM OF THIS REVIEW

The review aims at providing a detailed analysis of in silico, in vitro, in vivo, and clinical studies related to WS and cancer. It suggests possible role of WS in regulating molecular mechanisms associated with carcinogenesis. The review discusses potential of WS in cancer management in terms of cancer prevention, anti-cancer activity, and enhancing efficacy of cancer therapeutics.

MATERIAL AND METHODS

The present narrative review offers a critical analysis of published literature on WS studies in cancer. The reported studies were analysed in the context of pathophysiology of cancer, commonly referred as 'cancer hallmarks'. The review attempts to bridge Ayurveda knowledge with biological insights into molecular mechanisms of cancer.

RESULTS

Critical analysisof the published literature suggests an anti-cancer potential of WS with a key role in cancer prevention. The possible mechanisms for these effects are associated with the modulation of apoptotic, proliferative, and metastatic markers in cancer. WS can attenuate inflammatory responses and enzymes involved in invasion and metastatic progression of cancer.The properties of WS are likely to be mediated through withanolides, which may activate tumor suppressor proteins to restrict proliferation of cancer cells. Withanolides also regulate the genomic instability, and energy metabolism of cancer cells. The reported studies indicate the need for deeper understanding of molecular mechanisms of WS in inhibiting angiogenesis and promoting immunosurveillance. Additionally, WS can augment efficacy and safety of cancer therapeutics.

CONCLUSION

The experimentally-supported evidence of immunomodulatory, anti-cancer, adaptogenic, and regenerative attributes of WS suggest its therapeutic adjuvant potential in cancer management. The adjuvant properties of withanolides can modulate multidrug resistance and reverse chemotherapy-induced myelosuppression. These mechanisms need to be further explored in systematically designed translational and clinical studies that will pave the way for integration of WS as a therapeutic adjuvant in cancer management.

Molecular modeling approaches of selective adenosine receptor type 2A agonists as potential anti-inflammatory drugs

Adenosine A_2A receptor (A_2AR) is the predominant receptor in immune cells, where its activation triggers cAMP-mediated immunosuppressive signaling and the underlying inhibition of T cells activation and T cells-induced effects mediated by cAMP-dependent kinase proteins mechanisms. In this study, were used ADME/Tox, molecular docking and molecular dynamics simulations to investigate selective adenosine A_2AR agonists as potential anti-inflammatory drugs. As a result, we obtained two promising compounds (A and B) that have satisfactory pharmacokinetic and toxicological properties and were able to interact with important residues of the A_2AR binding cavity and during the molecular dynamics simulations were able to keep the enzyme complexed.Communicated by Ramaswamy H. Sarma.

Bioinformatics analysis of key biomarkers and potential molecular mechanisms in hepatocellular carcinoma induced by hepatitis B virus

BACKGROUND

Hepatocellular carcinoma (HCC) accounts for up to 90% of all primary hepatic malignancies; it is the sixth most common cancer and the second most common cause of cancer mortality worldwide. Numerous studies have shown that hepatitis B virus and its products, HBV integration, and mutation can induce HCC. However, the molecular mechanisms underpinning the regulation of HCC induced by HBV remain unclear.

METHODS

We downloaded 2 gene expression profiling datasets, of HBV and of HCC induced by HBV, from the gene expression omnibus (GEO) database. Differentially expressed genes (DEGs) between HCC and HBV were identified to explore any predisposing changes in gene expression associated with HCC. DEGs between HCC and adjacent healthy tissues were investigated to identify genes that may play a key role in HCC. Any overlapping genes among these DEGs were included in our bioinformatics analysis. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of overlapping genes were performed using the Metascape online database; the protein-protein interaction (PPI) network was analyzed using the STRING online database; and we obtained the hub genes of the PPI network using Cytoscape software. An overall survival (OS) analysis of hub genes was performed using km-plotter and the gene expression profiling interactive analysis (GEPIA) online database. The expression levels of hub genes were determined using the TCGA and GEPIA databases. Finally, the relationships between hub genes and tumors were analyzed using the comparative toxicogenomics database (CTD).

RESULTS

We identified 113 overlapping genes from the 2 datasets. Using functional and pathway analyses, we found that the overlapping genes were mainly related to the AMPK signaling pathway and cellular responses to cadmium ions. C8A, SPP2, KLKB1, PROZ, C6, FETUB, MBL2, HGFAC, C8B, and ANGPTL3 were identified as hub genes and C8A, SPP2, PROZ, C6, HGFAC, and C8B were found to be significant for survival.

CONCLUSION

The DEGs re-analyzed between HCC and hepatitis B enable a systematic understanding of the molecular mechanisms of HCC reliant on hepatitis B virus.

Effect of High-Dose Topical Minoxidil on Erythrocyte Quality in SKH1 Hairless Mice

Simple Summary

In any animal species, involuntary exposure to unknown agents may increase genetic material damage. This genetic damage can also induce the appearance of diseases such as cancer or other pathologies, including problems that can be passed on to the offspring of the damaged individual. For instance, living organisms may be affected due to the use of medications or exposure to certain chemical, physical, or biological agents which cause cell failure. This impaired function acts as an indicator that helps identify and evaluate damage in order to avoid or minimize it. In this work, excessive doses of a cosmetic drug for topical use in dermatological treatments, known as minoxidil, produced defects in the blood of hairless mice, particularly in red cells, indicating loss of DNA, a situation that may compromise life or the offspring by causing damage to their genetic material. It is important to consider that compounds may be tissue- or species-specific, although we cannot rule out the possibility that similar damage could occur in other animal species. Thus, excessive exposure to this compound should be prevented.

Abstract

SKH1 hairless mice are widely used in carcinogenesis and dermatology research due to their bare skin, as exposure to different agents is facilitated. Minoxidil is a cosmetic drug that is recognized as a mitogenic agent, and mitogens are suggested to have carcinogenic and mutagenic potential by inducing cell division and increasing the possibility of perpetuating DNA damage. Therefore, we hypothesized that the application of high doses of minoxidil to the skin of hairless mice would increase the number of micronucleated erythrocytes (MNEs) in peripheral blood. The objective of this study was to evaluate the topical administration of high doses of minoxidil on peripheral blood erythrocytes of SKH1 mice by means of micronucleus assay. Minoxidil was administered on the entire body surface of mice every 12 or 24 h. Minoxidil dosing every 24 h increased the number of micronucleated polychromatic erythrocytes (MNPCEs), and dosing every 12 h increased the number of MNEs and MNPCEs, as compared to baseline and the negative control group. No decrease in polychromatic erythrocyte frequencies was observed in the minoxidil groups. Therefore, topical application of high minoxidil doses to mice can produce DNA damage, as observed through an increase in the number of MNEs, without producing cytotoxicity, possibly due to its mitogenic effect.

Adverse outcome pathways for chemical toxicity and their applications to workers' health: a literature review

OBJECTIVE AND METHODS

Various papers related to the application of adverse outcome pathways (AOPs) for the prevention of occupational disease were reviewed. The Internet was used as the primary tool to search for the necessary research data and information, using such online resources as Google Scholar, ScienceDirect, Scopus, NDSL, and PubMed. The key search terms were "adverse outcome pathway," "toxicology," "risk assessment," "human," "worker," "occupational safety and health," and so on.

RESULTS AND CONCLUSION

The aim of this paper is to explain the use of AOP for the understanding of chemical toxicity as a conceptual means and to predict the toxic mechanism. The tools of AOP have emerged as a forward-looking alternative to the existing chemical risk assessment paradigm. AOP is being applied to the assessment of acute toxicity and to chronic toxic chemicals in the workplace. Not only can it lead to breakthroughs in occupational and environmental cancer prevention, it is also widely used in chemical risk assessment and has led to breakthroughs in the prevention of occupational disease in the workplace.

A link between environmental pollution and civilization disorders: a mini review

Most civilization disorders have a complex etiology, involving factors such as genetics, lifestyle, and environmental pollution (EP) due to different chemicals. Among harmful chemicals, the major ones include particulate matter (PM), nitrogen oxides, polycyclic aromatic hydrocarbons (PAHs), heavy metals, pesticides, plasticizers, polychlorinated biphenyls (PCBs), dioxins, furans, some food additives, hormones, and antibiotics. In fact, potential pollutants are countless and most of them have never been evaluated in terms of their toxicity and health risks, especially that new chemicals emerge all the time due to interactions between the existing ones. It is almost impossible to determine the effects of these new compounds on health. Previous studies have revealed a broad spectrum of diseases related to pollution. EP has been associated with an increased incidence of some malignancies, an increased rate of all-cause mortality, development or exacerbation of cardiovascular diseases, recurrent infections, impairment of intellectual and psychomotor development in children, development of type 2 diabetes, respiratory and immune system diseases, and also brain degenerative disorders. EP is an important cause of morbidity and mortality worldwide, generating high health care costs. Global pollution questions the common recommendation to eat vegetables, fruit, and fish regularly as part of a healthy diet, if they do not have ecological certification. Research in the fields of ecology, biology, and toxicology is needed to determine which environmental contaminants are the most hazardous to wildlife and humans and at what levels. Only an interdisciplinary cooperation and measures to raise public awareness could help improve environmental protection.

Chemopreventive role of arabinogalactan against experimentally induced pulmonary carcinogenesis: a study in relation to its initiation phase

The aim of the present study is to divulge the chemopreventive potential of arabinogalactan (AG) on benzo(a)pyrene [B(a)P] induced initiation of lung carcinogenesis. AG is one of the naturally occurring bioactive polysaccharides which is widely found in medicinal plants. Male Balb/c mice were divided into four experimental groups. Group I served as control. Group II animals were injected with B(a)P (50 mg/kg b. wt. i.p.). Group III animals were administered with AG (7.5 mg/kg b.wt.) orally. Group IV animals received B(a)P and AG as in group II and group III, respectively. B(a)P treatment in mice resulted in imbalance of carcinogen metabolizing enzymes and respiratory marker enzymes at 2nd, 6th and 10th week of the experimental protocol. Also, it leads to the increased protein synthesis as depicted by increased argyrophilic nucleolar organizer regions (AgNOR) positive cells and altered histopathological features. Studies on bronchoalveolar lavage fluid (balf) of B(a)P exposed animals revealed increase in surface tension when compared with control counterparts. Apart from target tissue (lung), B(a)P also led to the clastogenic damage in other tissues (spleen and bone marrow) as depicted by increase in percentage of micronucleus cells at different time intervals. Treatment with AG efficiently counteracted all the above anomalies and restored cellular homeostasis. These observations suggest that AG has the potential to modulate B(a)P induced changes in the pulmonary tissue as well as other tissues which could have implications in delaying the initiation of carcinogenesis, however, further investigations are required to explore its complete mechanism of action.

Changes in Biological Pathways During 6,000 Years of Civilization in Europe

The beginning of civilization was a turning point in human evolution. With increasing separation from the natural environment, mankind stimulated new adaptive reactions in response to new environmental factors. In this paper, we describe direct signs of these reactions in the European population during the past 6,000 years. By comparing whole-genome data between Late Neolithic/Bronze Age individuals and modern Europeans, we revealed biological pathways that are significantly differently enriched in nonsynonymous single nucleotide polymorphisms in these two groups and which therefore could be shaped by cultural practices during the past six millennia. They include metabolic transformations, immune response, signal transduction, physical activity, sensory perception, reproduction, and cognitive functions. We demonstrated that these processes were influenced by different types of natural selection. We believe that our study opens new perspectives for more detailed investigations about when and how civilization has been modifying human genomes.

A Polymorphic Variant in p19Arf Confers Resistance to Chemically Induced Skin Tumors by Activating the p53 Pathway

Identification of the specific genetic variants responsible for the increased susceptibility to familial or sporadic cancers is important. Using a forward genetics approach to map such loci in a mouse skin cancer model, we previously identified a strong genetic locus, Stmm3, conferring resistance to chemically induced skin papillomas on chromosome 4. Here, we report the cyclin-dependent kinase inhibitor gene Cdkn2a/p19^Arf as a major responsible gene for the Stmm3 locus. We provide evidence that the function of Stmm3 is dependent on p53 and that p19^ArfMSM confers stronger resistance to papillomas than p16^Ink4aMSMin vivo. In addition, we found that genetic polymorphism in p19^Arf between a resistant strain, MSM/Ms (Val), and a susceptible strain, FVB/N (Leu), alters the susceptibility to papilloma development, malignant conversion, and the epithelial-mesenchymal transition. Moreover, we demonstrated that the p19^ArfMSM allele more efficiently activates the p53 pathway than the p19^ArfFVB allele in vitro and in vivo. Furthermore, we found polymorphisms in CDKN2A in the vicinity of a polymorphism in mouse Cdkn2a associated with the risk of human cancers in the Japanese population. Genetic polymorphisms in Cdkn2a and CDKN2A may affect the cancer risk in both mice and humans.

Application of the Adverse Outcome Pathway Framework to Risk Assessment for Predicting Carcinogenicity of Chemicals

As industry develops in modern society, many chemicals are being used. The safety of chemicals is an important issue because humans are constantly exposed to chemicals throughout their daily life. Through a risk assessment, the hazardous human effects of chemicals can be identified. Recently, the adverse outcome pathway (AOP) framework has been used to predict the adverse effects of chemicals. As a conceptual framework for organizing existing biological knowledge, the AOP consists of a molecular initiating event, key events, and an adverse outcome. These independent elements represent biological responses and are connected by key event relationships. This AOP framework provides intuitive hazard identification that can be helpful for carcinogenic risk assessment of chemicals. In this review, we introduce the application of the AOP framework to risk assessment for predicting carcinogenicity of chemicals and illustrate the utility of this approach for cancer prevention.

Therapeutic effect of simvastatin on DMBA-induced breast cancer in mice

Preclinical studies have shown positive effects of statins against specific cancers. This study aimed to determine the therapeutic effect of simvastatin in 12-dimethylbenz(a)anthracene (DMBA)-induced breast cancer. Female albino mice were divided into two groups, with or without DMBA administration. After tumor appearance, DMBA-treated group was further divided into four groups (D1-D4) as control (D1), treated with simvastatin at 80 and 40 mg/kg/day, orally (D2 and D3) and tamoxifen (50 mg/kg/day, orally) treated group (D4). After 4 weeks, animals were sacrificed, serum samples were collected and tumors were dissected for histopathological study and determination of selected parameters. The tumor marker carcinoma antigen 15-3 (CA15-3), oxidative stress parameters and prostaglandin E2 (PGE2) levels were analyzed in serum and tumors in experimental groups. Tamoxifen and high dose of simvastatin improved parameters of mammary carcinogenesis including mean tumor volume, body weight and percent of mortality as compared to mice with breast tumors without treatment (D1). Additionally, simvastatin usage increased total antioxidant capacity (TAC) level, paraoxonase 1 (PON1) activity in serum and decreased total oxidant status (TOS) and malondialdehyde (MDA) levels in tumors similar to tamoxifen. No significant decrease was found in serum CA 15-3 and tumor PGE2 levels in simvastatin and tamoxifen treated groups as compared to D1 group. These data suggest that simvastatin has anticancer effects which are relatively similar to that of tamoxifen in an animal model of breast cancer.

Vanadium quercetin complex attenuates mammary cancer by regulating the P53, Akt/mTOR pathway and downregulates cellular proliferation correlated with increased apoptotic events

Flavonoid metal ion complexes have been deliberated in recent years and are considered as a new class of medicinal agents with enhanced therapeutic activity and low toxicity. Our study deals with chemotherapeutic effects of vanadium, when coordinated with the flavonoid quercetin on a defined model of chemically induced rat mammary carcinogenesis in vivo and on human breast cancer cell line MCF-7 in vitro. The characterization of the complex was achieved through UV-Visible, IR, and Mass spectra and antioxidant activity was assessed by DPPH, FRAP and ABTS methods. In vitro studies established that the complex upregulated the expressions of p53, Caspase 3 and 9, whereas down regulating Akt, mTOR and VEGF expressions and also induced apoptosis and DNA fragmentation in a dose dependent manner. Acute and Sub-acute toxicity was performed to determine safe doses. 7,12-Dimethylbenz(α)anthracene (0.5 mg/100 g body weight) was used for induction of breast cancer in female Sprague-Dawley rats via single tail vein injection. The histopathological analysis after 24 weeks of carcinogenesis study depicted substantial repair of hyperplastic lesions. TUNEL assay showed an increase in apoptotic index (0.14 ± 0.03; 0.15 ± 0.01) in vanadium-quercetin treated groups as compared to the carcinogen control (0.02 ± 0.01) along with upregulation of Bcl-2 and downregulation of Bax and p53. Immunohistochemical analysis also exhibited decrease in cell proliferation in the vanadium-quercetin treated groups (11.3 ± 0.12; 11.8 ± 0.10). Thus, results from both in vivo and in vitro studies revealed that vanadium-quercetin complex could be a potential candidate for development of approved drug for breast cancer in the near future.

Antimutagenic and Antioxidant Activities of Thai Rice Brans

Background

Rice bran is the outer layer of the rice grain, and contains high amounts of bioactive phytochemicals. Here, we investigated and compared chemopreventive properties of purple and white rice bran extracts.

Methods

Rice bran was extracted with dichloromethane and methanol. Chemical constituents in the extracts were analyzed by colorimetric assay and high performance liquid chromatography. The mutagenicity and antimutagenicity of the extracts were determined via the Salmonella mutation assay. The anticarcinogenic enzyme induction and antioxidant activities of the extracts were examined using Hepa1c1c7 cells and 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay, respectively.

Results

The methanol extracts of rice bran contained high amounts of phenolic acids, flavonoids, anthocyanins, and phytic acid, whereas large amounts of γ-oryzanol and vitamin E were presented in the dichloromethane extract. None of the extracts were mutagenic to Salmonella typhimurium. All rice bran extracts had strong antimutagenic effects against aflatoxin B₁- and 2-amino-3,4-dimethylimidazo [4,5-f]quinoline-induced mutagenesis. The inhibitory effect against 2-aminofluorene-induced mutagenesis was found in the dichloromethane extract, while only the methanol extract of purple rice bran exhibited antimutagenic effects against benzo(a)pyrene. None of the extracts induced quinone reductase activity in Hepa1c1c7 cells. Additionally, the greatest antioxidant capacity was found in the methanol extract of purple rice bran.

Conclusions

The methanol extract of purple rice bran containing high amount of phenolic acids, flavonoids, anthocyanins, and phytic acid showed the most effective antioxidant and antimutagenic activities by inhibiting mutagenic metabolizing enzymes and/or scavenging free radicals. These results demonstrate the nutritional and medical value of Thai rice for cancer prevention.

Quercetin Reverses Rat Liver Preneoplastic Lesions Induced by Chemical Carcinogenesis

Quercetin is a flavonoid widely studied as a chemopreventive agent in different types of cancer. Previously, we reported that quercetin has a chemopreventive effect on the liver-induced preneoplastic lesions in rats. Here, we evaluated if quercetin was able not only to prevent but also to reverse rat liver preneoplastic lesions. We used the modified resistant hepatocyte model (MRHM) to evaluate this possibility. Treatment with quercetin was used 15 days after the induction of preneoplastic lesions. We found that quercetin reverses the number of preneoplastic lesions and their areas. Our results showed that quercetin downregulates the expression of EGFR and modulates this signaling pathway in spite of the activated status of EGFR as detected by the upregulation of this receptor, with respect to that observed in control rats. Besides, quercetin affects the phosphorylation status of Src-1, STAT5, and Sp-1. The better status of the liver after the treatment with quercetin could also be confirmed by the recovery in the expression of IGF-1. In conclusion, we suggest that quercetin reversed preneoplastic lesions by EGFR modulation and the activation state of Src, STAT5, and Sp1, so as the basal IGF-1.

Animal models as a tool in hepatocellular carcinoma research: A Review

Cancer is the first cause of death in developed countries and the second in developing countries. Concerning the most frequent worldwide-diagnosed cancer, primary liver cancer represents approximately 4% of all new cancer cases diagnosed globally. However, among primary liver cancer, hepatocellular carcinoma is by far the most common histological subtype. Notwithstanding the health promotion and disease prevention campaigns, more than half a million new hepatocellular carcinoma cases are reported yearly, being estimated to growth continuously until 2020. Taking this scenario under consideration and the fact that some aspects concerning hepatocellular carcinoma evolution and metastasize process are still unknown, animal models assume a crucial role to understand this disease. The animal models have also provided the opportunity to screen new therapeutic strategies. The present review was supported on research and review papers aiming the complexity and often neglected chemically induced animal models in hepatocarcinogenesis research. Despite the ongoing debate, chemically induced animal models, namely, mice and rat, can provide unique valuable information on the biotransformation mechanisms against xenobiotics and apprehend the deleterious effects on DNA and cell proteins leading to carcinogenic development. In addition, taking under consideration that no model achieves all hepatocellular carcinoma research purposes, criteria to define the " ideal" animal model, depending on the researchers' approach, are also discussed in this review.

Experimental mammary carcinogenesis - Rat models

Mammary cancer is one of the most common cancers, victimizing more than half a million of women worldwide every year. Despite all the studies in this field, the current therapeutic approaches are not effective and have several devastating effects for patients. In this way, the need to better understand the mammary cancer biopathology and find effective therapies led to the development of several rodent models over years. With this review, the authors intended to provide the readers with an overview of the rat models used to study mammary carcinogenesis, with a special emphasis on chemically-induced models.

Gene silencing of Nox4 by CpG island methylation during hepatocarcinogenesis in rats

The association between the downregulation of genes and DNA methylation in their CpG islands has been extensively studied as a mechanism that favors carcinogenesis. The objective of this study was to analyze the methylation of a set of genes selected based on their microarray expression profiles during the process of hepatocarcinogenesis. Rats were euthanized at: 24 h, 7, 11, 16 and 30 days and 5, 9, 12 and 18 months post-treatment. We evaluated the methylation status in the CpG islands of four deregulated genes (Casp3, Cldn1, Pex11a and Nox4) using methylation-sensitive high-resolution melting technology for the samples obtained from different stages of hepatocarcinogenesis. We did not observe methylation in Casp3, Cldn1 or Pex11a. However, Nox4 exhibited altered methylation patterns, reaching a maximum of 10%, even during the early stages of hepatocarcinogenesis. We observed downregulation of mRNA and protein of Nox4 (97.5% and 40%, respectively) after the first carcinogenic stimulus relative to the untreated samples. Our results suggest that Nox4 downregulation is associated with DNA methylation of the CpG island in its promoter. We propose that methylation is a mechanism that can silence the expression of Nox4, which could contribute to the acquisition of neoplastic characteristics during hepatocarcinogenesis in rats.

Summary: Many genes downregulated by DNA methylation are tumor suppressor genes. In the present study, DNA methylation of Nox4 is observed, with implications for Nox4 as a potential therapeutic target for liver or other cancers.

Environmental carcinogenesis and pH homeostasis: Not only a matter of dysregulated metabolism

According to the World Health Organization, around 20% of all cancers would be due to environmental factors. Among these factors, several chemicals are indeed well recognized carcinogens. The widespread contaminant benzo[a]pyrene (B[a]P), an often used model carcinogen of the polycyclic aromatic hydrocarbons' family, has been suggested to target most, if not all, cancer hallmarks described by Hanahan and Weinberg. It is classified as a group I carcinogen by the International Agency for Research on Cancer; however, the precise intracellular mechanisms underlying its carcinogenic properties remain yet to be thoroughly defined. Recently, the pH homeostasis, a well known regulator of carcinogenic processes, was suggested to be a key actor in both cell death and Warburg-like metabolic reprogramming induced upon B[a]P exposure. The present review will highlight those data with the aim of favoring research on the role of H⁺ dynamics in environmental carcinogenesis.

Chemopreventive Agents Attenuate Rapid Inhibition of Gap Junctional Intercellular Communication Induced by Environmental Toxicants

Altered gap junctional intercellular communication (GJIC) has been associated with chemical carcinogenesis, where both chemical tumor promoters and chemopreventive agents (CPAs) are known to conversely modulate GJIC. The aim of this study was to investigate whether attenuation of chemically inhibited GJIC represents a common outcome induced by different CPAs, which could be effectively evaluated using in vitro methods. Rat liver epithelial cells WB-F344 were pretreated with a CPA for either 30 min or 24 h, and then exposed to GJIC-inhibiting concentration of a selected tumor promoter or environmental toxicant [12-O-tetradecanoylphorbol-13-acetate (TPA), lindane, fluoranthene, 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT), perfluorooctanoic acid (PFOA), or pentachlorophenol]. Out of nine CPAs tested, quercetin and silibinin elicited the most pronounced effects, preventing the dysregulation of GJIC by all the GJIC inhibitors, but DDT. Metformin and curcumin attenuated the effects of three GJIC inhibitors, whereas the other CPAs prevented the effects of two (diallyl sulfide, emodin) or one (indole-3-carbinol, thymoquinone) GJIC inhibitor. Significant attenuation of chemically induced inhibition of GJIC was observed in 27 (50%) out of 54 possible combinations of nine CPAs and six GJIC inhibitors. Our data demonstrate that in vitro evaluation of GJIC can be used as an effective screening tool for identification of chemicals with potential chemopreventive activity.

Interleukin-17A Plays a Pivotal Role in Chemically Induced Hepatocellular Carcinoma in Mice

AIM

The aim of the present study was to investigate the role of interleukin (IL)-17A in the initiation and progression of hepatocellular carcinoma.

METHODS

IL-17A deficient (KO) and wild-type (WT) mice were intraperitoneal injected with diethyl nitrosamine (DEN) to induce hepatocellular carcinoma, and the incidence of tumours was assessed 38 weeks later. In order to investigate the effects of DEN on hepatocytes in the acute phase of DEN administration, DEN-treated mice were sacrificed at designated time points. Serum and liver tissues were harvested for further analyses.

RESULTS

The tumor incidence was approximately 65 % in WT mice, but was significantly lower (by 20 %) in KO mice. The number of tumours was also less in KO mice. Serum ALT levels increased in WT mice 7 days after the administration of DEN, but were significantly lower in KO mice. Furthermore, the number of neutrophils and Kupffer cells, and the expression of TNF-α and IL-6 were reduced in KO mice. The intrahepatic expression of the oxidative DNA damage marker 8-OHdG and lipid oxidative marker 4-HNE was markedly increased in WT mice, but was significantly lower in KO mice. In addition, the increase of cell proliferation, as assessed by Ki-67 immunohistochemistry, in WT mice was significantly reduced in KO mice.

CONCLUSION

These results demonstrated that IL-17A plays a pivotal role in chemically induced hepatic carcinogenesis, which is most likely through inflammation-initiated oxidative DNA damage and cell proliferation.

Dietary mycotoxins, co-exposure, and carcinogenesis in humans: Short review

Mycotoxins, toxic secondary metabolites of fungi, affect global agriculture so prolifically that they are virtually ubiquitous at some concentration in the average human diet. Studies of in vitro and in vivo toxicity are discussed, leading to investigations of co-exposed mycotoxins, as well as carcinogenic effects. Some of the most common and toxicologically significant mycotoxins, such as the aflatoxins, ochratoxins, fumonisins, deoxynivalenol, T-2 toxin, HT-2 toxin, patulin, zearalenone, and some ergot alkaloids are outlined. The wide variety of pathogenic mechanisms these compounds employ are shown capable of inducing a complex set of interactions. Of particular note are potential synergisms between mycotoxins with regard to carcinogenic attributable risk, indicating an important field for future study.

Mammalian models of chemically induced primary malignancies exploitable for imaging-based preclinical theragnostic research

Compared with transplanted tumor models or genetically engineered cancer models, chemically induced primary malignancies in experimental animals can mimic the clinical cancer progress from the early stage on. Cancer caused by chemical carcinogens generally develops through three phases namely initiation, promotion and progression. Based on different mechanisms, chemical carcinogens can be divided into genotoxic and non-genotoxic ones, or complete and incomplete ones, usually with an organ-specific property. Chemical carcinogens can be classified upon their origins such as environmental pollutants, cooked meat derived carcinogens, N-nitroso compounds, food additives, antineoplastic agents, naturally occurring substances and synthetic carcinogens, etc. Carcinogen-induced models of primary cancers can be used to evaluate the diagnostic/therapeutic effects of candidate drugs, investigate the biological influential factors, explore preventive measures for carcinogenicity, and better understand molecular mechanisms involved in tumor initiation, promotion and progression. Among commonly adopted cancer models, chemically induced primary malignancies in mammals have several advantages including the easy procedures, fruitful tumor generation and high analogy to clinical human primary cancers. However, in addition to the time-consuming process, the major drawback of chemical carcinogenesis for translational research is the difficulty in noninvasive tumor burden assessment in small animals. Like human cancers, tumors occur unpredictably also among animals in terms of timing, location and the number of lesions. Thanks to the availability of magnetic resonance imaging (MRI) with various advantages such as ionizing-free scanning, superb soft tissue contrast, multi-parametric information, and utility of diverse contrast agents, now a workable solution to this bottleneck problem is to apply MRI for noninvasive detection, diagnosis and therapeutic monitoring on those otherwise uncontrollable animal models with primary cancers. Moreover, it is foreseeable that the combined use of chemically induced primary cancer models and molecular imaging techniques may help to develop new anticancer diagnostics and therapeutics.