Aflatoxin B1 inhibits the type 1 interferon response pathway via STAT1 suggesting another mechanism of hepatocellular carcinoma

When less is more: The association between the expression of polymorphic CYPs and AFB1-induced HCC

BACKGROUND

An individual's genetic fingerprint is emerging as a pivotal predictor of numerous disease- and treatment-related factors. Single nucleotide polymorphisms (SNPs) in drug-metabolizing enzymes play key roles in an individual's exposure to a malignancy-associated risk, such as Aflatoxin B1 (AFB1)-induced hepatocellular carcinoma (HCC).

AIM

This study aimed at reviewing literature on the polymorphisms that exist in CYP enzymes and their possible link with susceptibility to AFB1-induced HCC.

MATERIALS & METHODS

A set of keywords associated with the study subject of interest was used to search the Google Scholar and the PubMed database. The last ten years' worth of research projects were included in the results filter. The research involved HCC patients and any connection between polymorphic forms of CYP enzymes and their susceptibility to AFB1-induced HCC, including older but significant data.

RESULTS

Variations in CYP1A2 and CYP3A4 were reported to impact the rate and magnitude of AFB1 bio-activation, thus influencing an individual's vulnerability to develop HCC. In HCC patients, the activity of CYP isoforms varies, where increased activity has been reported with CYP2C9, CYP2D6, and CYP2E1, while CYP1A2, CYP2C8, and CYP2C19 exhibit decreased activity. CYP2D6*10 frequency has been discovered to differ considerably in HCC patients. Rs2740574 (an upstream polymorphism in CYP3A4 as detected in CYP3A4*1B) and rs776746 (which affects CYP3A5 RNA splicing), both of which influence CYP3A expression, thus impacting the variability of AFB1-epoxide adducts in HCC patients.

DISCUSSION

CYP1A2 is the primary enzyme accountable for the formation of harmful AFBO globally. CYP3A4, CYP3A5, CYP3A7, CYP2B7, and CYP3A3 are also implicated in the bio-activation of AFB1 to mutagenic metabolites. It is thought that CYP3A4 is the protein that interacts with AFB1 metabolism the most.

CONCLUSION

Polymorphic variants of CYP enzymes have a functional impact on the susceptibility to AFB1-induced HCC. Outlining such variation and their implications may provide deeper insights into approaching HCC in a more personalized manner for guiding future risk-assessment, diagnosis, and treatment.

Genotoxic and cytotoxic effects of aflatoxin on the reproductive system: Focus on cell cycle dynamics and apoptosis in testicular tissue

Aflatoxins (AFs) are inevitable environmental contaminants that are detrimental to human and animal health. AFs interfere with metabolic processes, metabolizing into different hydroxylated derivatives in the liver, as well as mechanistically induce ROS accumulation, S-phase arrest, DNA damage, and cell apoptosis. Chronic consumption of aflatoxin-contaminated foods can adversely affect the male reproductive system, cause testicular damage, prevent testosterone synthesis, decline sperm quality, and cause infertility. Oxidative stress is the fundamental pathogenesis of aflatoxin-induced reproductive toxicity. The overproduction of reactive oxygen substances can cause testicular failure and disturb the process of spermatogenesis. Mitochondria are susceptible to being impaired by oxidative stress, and its damage is associated with infertility. AFs also disturb the process of spermatogenesis by disrupting the regulation of genes related to the progression of the cell cycle such as cyclins and inducing genes related to apoptosis, thereby weakening fertility and negatively affecting the testicular endocrine potential by suppressing androgen synthesis. Additionally, AFs downregulate ERα expression, potentially negatively impacting spermatogenesis by enhancing the apoptotic mechanism. In this review, we provide new insights into the genotoxic and cytotoxic effects of AFB1 on the male reproductive system with a focus on the cell cycle and apoptosis destruction of testicular tissue.

Aflatoxin B1 in poultry liver: Toxic mechanism

Aflatoxin B1 (AFB1) is the most common carcinogenic toxin in livestock and poultry feed, seriously endangering poultry production and public health. Liver is the most important organ for the metabolism of exogenous and endogenous substances in the body. AFB1 produces toxicity under the biotransformation of cytochrome P450 microparticle oxidase (CYP450). Hepatocytes are the most important cells for synthesizing CYP450 enzymes, so that AFB1 has the most significant effect on the liver. AFB1 can induce liver cell damage in poultry through a variety of molecular mechanisms, and the main of damage mechanisms have been discovered so far include oxidative damage, promoting apoptosis, influencing hepatocyte gene expression, interfering with hepatocyte autophagy, pyroptosis and necroptosis. This article reviewed the molecular mechanism of AFB1 inducing liver injury in poultry, hopefully, to provid a new direction and theoretical basis for the development of a new AFB1 detoxification method.

A novel cuproptosis-related lncRNA signature predicts the prognosis and immunotherapy for hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most serious malignant tumors with a poor prognosis worldwide. Cuproptosis is a novel copper-dependent cell death form, involving mitochondrial respiration and lipoylated components of the tricarboxylic acid (TCA) cycle. Long non-coding RNAs (lncRNAs) have been demonstrated to affect the tumorigenesis, growth, and metastasis of HCC.

OBJECTIVE

We explored the potential roles of cuproptosis-related lncRNAs in predicting the prognosis for HCC.

METHODS

The RNA-seq transcriptome data, mutation data, and clinical information data of HCC patients were downloaded from The Cancer Genome Atlas (TCGA) database. The least absolute shrinkage and selection operator (LASSO) algorithm and Cox regression analyses were performed to identify a prognostic cuproptosis-related lncRNA signature. The receiver operating characteristic (ROC) analysis was used to evaluate the predictive value of the lncRNA signature for HCC. The enrichment pathways, immune functions, immune cell infiltration, tumor mutation burden, and drug sensitivity were also analyzed.

RESULTS

We constructed a prognostic model consisting of 8 cuproptosis-related lncRNAs for HCC. The patients were divided into high-risk group and low-risk group according to the riskscore calculated using the model. Kaplan-Meier analysis revealed that the high-risk lncRNA signature was correlated with poor overall survival [hazard ratio (HR) =1.009, 95% confidence interval (CI) = 1.002-1.015; p= 0.010)] of HCC. A prognostic nomogram incorporated the lncRNA signature and clinicopathological features were constructed and showed favorable performance for predicting prognosis of HCC patients. In addition, the most immune-related functions were significantly different between the high-risk and low-risk groups. Tumor mutation burden (TMB) and immune checkpoints were also expressed differently between the two risk groups. Finally, HCC patients with low-risk score were more sensitive to several chemotherapy drugs.

CONCLUSIONS

The novel cuproptosis-related lncRNA signature could be used to predict prognosis and evaluate the effect of chemotherapy for HCC.

CD5L-associated gene analyses highlight the dysregulations, prognostic effects, immune associations, and drug-sensitivity predicative potentials of LCAT and CDC20 in hepatocellular carcinoma

BACKGROUND

The dysregulation of CD5L has been reported in hepatocellular carcinoma (HCC). However, its functions in HCC were controversial. In this study, we aimed to identify CD5L-associated pathways and markers and explore their values in HCC diagnosis, prognosis and treatment.

METHODS

HCC datasets with gene expression profiles and clinical data in TCGA and ICGC were downloaded. The immune/stroma cell infiltrations were estimated with xCell. CD5L-associated pathways and CD5L-associated genes (CD5L-AGs) were identified with gene expression comparisons and gene set enrichment analysis (GSEA). Cox regression, Kaplan-Meier survival analysis, and least absolute shrinkage and selection operator (LASSO) regression analysis were performed. The correlations of the key genes with immune/stroma infiltrations, immunoregulators, and anti-cancer drug sensitivities in HCC were investigated. At protein level, the key genes dysregulations, their correlations and prognostic values were validated in clinical proteomic tumor analysis consortium (CPTAC) database. Serum CD5L and LCAT activity in 50 HCC and 30 normal samples were evaluated and compared. The correlations of serum LCAT activity with alpha-fetoprotein (AFP), albumin (ALB) and high-density lipoprotein (HDL) in HCC were also investigated.

RESULTS

Through systemic analyses, 14 CD5L-associated biological pathways, 256 CD5L-AGs and 28 CD5L-associated prognostic and diagnostic genes (CD5L-APDGs) were identified. A risk model consisting of LCAT and CDC20 was constructed for HCC overall survival (OS), which could discriminate HCC OS status effectively in both the training and the validation sets. CD5L, LCAT and CDC20 were shown to be significantly correlated with immune/stroma cell infiltrations, immunoregulators and 31 anti-cancer drug sensitivities in HCC. At protein level, the dysregulations of CD5L, LCAT and CDC20 were confirmed. LCAT and CDC20 were shown to be significantly correlated with proliferation marker MKI67. In serum, no significance of CD5L was shown. However, the lower activity of LCAT in HCC serum was obvious, as well as its significant positive correlations ALB and HDL concentrations.

CONCLUSIONS

CD5L, LCAT and CDC20 were dysregulated in HCC both at mRNA and protein levels. The LCAT-CDC20 signature might be new predicator for HCC OS. The associations of the three genes with HCC microenvironment and anti-cancer drug sensitivities would provide new clues for HCC immunotherapy and chemotherapy.

Research progress in toxicological effects and mechanism of aflatoxin B1 toxin

Fungal contamination of animal feed can severely affect the health of farm animals, and result in considerable economic losses. Certain filamentous fungi or molds produce toxic secondary metabolites known as mycotoxins, of which aflatoxins (AFTs) are considered the most critical dietary risk factor for both humans and animals. AFTs are ubiquitous in the environment, soil, and food crops, and aflatoxin B₁(AFB₁) has been identified by the World Health Organization (WHO) as one of the most potent natural group 1A carcinogen. We reviewed the literature on the toxic effects of AFB₁ in humans and animals along with its toxicokinetic properties. The damage induced by AFB₁ in cells and tissues is mainly achieved through cell cycle arrest and inhibition of cell proliferation, and the induction of apoptosis, oxidative stress, endoplasmic reticulum (ER) stress and autophagy. In addition, numerous coding genes and non-coding RNAs have been identified that regulate AFB₁ toxicity. This review is a summary of the current research on the complexity of AFB₁ toxicity, and provides insights into the molecular mechanisms as well as the phenotypic characteristics.

Proteomic Changes in Oral Keratinocytes Chronically Exposed to Shisha (Water Pipe)

Shisha (water pipe) smoking is falsely believed to be a hazard-free habit and has become a major public health concern. Studies have reported shisha smoking to be associated with oral lesions, as well as carcinomas of the lung, esophagus, bladder, and pancreas. A deeper understanding of the underlying molecular mechanisms would contribute to identification of biomarkers for targeted public health screening, therapeutic innovation, and better prognosis of associated diseases. In this study, we have established an in vitro chronic cellular model of shisha-exposed oral keratinocytes to study the effect of shisha on oral cells. Normal nontransformed, immortalized oral keratinocytes were chronically exposed to shisha extract for 8 months. This resulted in significant increase in cellular proliferation and cell invasion in shisha-exposed cells compared to the parental cells. Quantitative proteomic analysis of OKF6/TERT1-Parental and OKF6/TERT1-Shisha cells resulted in the identification of 5515 proteins. Forty-three differentially expressed proteins were found to be common across all conditions. Bioinformatic analysis of the dysregulated proteins identified in the proteomic study revealed dysregulation of interferon pathway, upregulation of proteins involved in cell growth, and downregulation of immune processes. The present findings reveal that chronic exposure of normal oral keratinocytes to shisha leads to cellular transformation and dysregulation of immune response. To the best of our knowledge, this is the first report that has developed a model of oral keratinocytes chronically exposed to shisha and identified proteomic alterations associated with shisha exposure. However, further research is required to evaluate the health burden of shisha smoking.

Identification of a Tumor Microenvironment-Related Eight-Gene Signature for Predicting Prognosis in Lower-Grade Gliomas

Lower-grade gliomas (LrGG), characterized by invasiveness and heterogeneity, remain incurable with current therapies. Clinicopathological features provide insufficient information to guide optimal individual treatment and cannot predict prognosis completely. Recently, an increasing amount of studies indicate that the tumor microenvironment plays a pivotal role in tumor malignancy and treatment responses. However, studies focusing on the tumor microenvironment (TME) of LrGG are still limited. In this study, taking advantage of the currently popular computational methods for estimating the infiltration of tumor-associated normal cells in tumor samples and using weighted gene co-expression network analysis, we screened the co-expressed gene modules associated with the TME and further identified the prognostic hub genes in these modules. Furthermore, eight prognostic hub genes (ARHGDIB, CLIC1, OAS3, PDIA4, PARP9, STAT1, TAP2, and TAGLN2) were selected to construct a prognostic risk score model using the least absolute shrinkage and selection operator method. Univariate and multivariate Cox regression analysis demonstrated that the risk score was an independent prognostic factor for LrGG. Moreover, time-dependent ROC curves indicated that our model had favorable efficiency in predicting both short- and long-term prognosis in LrGG patients, and the stratified survival analysis demonstrated that our model had prognostic value for different subgroups of LrGG patients. Additionally, our model had potential value for predicting the sensitivity of LrGG patients to radio- and chemotherapy. Besides, differential expression analysis showed that the eight genes were aberrantly expressed in LrGG compared to normal brain tissue. Correlation analysis revealed that the expression of the eight genes was significantly associated with the infiltration levels of six types of immune cells in LrGG. In summary, the TME-related eight-gene signature was significantly associated with the prognosis of LrGG patients. They might act as potential prognostic biomarkers for LrGG patients, offer better stratification for future clinical trials, and be candidate targets for immunotherapy, thus deserving further investigation.