An overview on possible links between aflatoxin B1 exposure and gallbladder cancer

Protective Effects of Propolis Supplementation on Aflatoxin B1-Induced Oxidative Stress, Antioxidant Status, Intestinal Barrier Damage, and Gut Microbiota in Rats

Aflatoxin B1 (AFB1) is common in the diets of humans and animals and often leads to adverse health effects. Propolis, with its strong antioxidant activity, can reduce oxidative stress and modulate gut microbiota composition. However, the underlying mechanism by which propolis alleviates AFB1-induced intestinal barrier damage remains unclear. This study was designed to investigate the protective effects of oral propolis supplementation in AFB1-exposed rats. Thirty-two male Sprague-Dawley rats were divided into four groups: control, AFB1, propolis, and AFB1+propolis. After 4 weeks, serum oxidative stress markers were examined, and gut microbiota was analyzed by 16S rRNA sequencing. Intestinal sections were processed by Hematoxylin & Eosin staining, and the expression level of tight junction proteins was assessed by immunostaining. Propolis supplementation in AFB1-exposed rats tended to decrease oxidative stress, and it also restructured the gut microbiota by preventing a decrease in the relative abundances of Lactobacillus, Roseburia, and Phascolarctobacterium. Propolis restored intestinal permeability impaired by AFB1 by ameliorating intestinal morphological damage and increasing the expression levels of tight junction proteins. Propolis supplementation may contribute to the modulation of gut microbiota by alleviating oxidative stress and improving intestinal barrier damage in AFB1-exposed rats.

Aflatoxin exposure is associated with an increased risk of gallbladder cancer

Gall bladder cancer (GBC) is common among the socioeconomically deprived populations of certain geographical regions. Aflatoxin is a genotoxic hepatocarcinogen, which is recognized to have a role in the pathogenesis of hepatocellular carcinoma. However, the role of aflatoxin in the pathogenesis of GBC is largely unknown. We determined serum AFB1-Lys albumin adduct (AAA) levels as a marker of aflatoxin exposure in the patients with GBC and compared to those without GBC. The relationship of AAA levels to cytogenetic (TP53mutation&HER2/neu amplification) and radiological characteristics of the tumor was assessed. We included GBC cases (n = 51) and non-GBC controls (n = 100). Mean serum AAA levels were higher in the GBC group (n = 51) than those without GBC (n = 100) (26.1 ± 12.2 vs. 13.1 ± 11.9 ng/mL; p < .001). HER2/neu expression was associated with higher AAA levels compared to those with equivocal or negative expression (43.9 ± 3 vs. 28.6 ± 10 vs. 19.3 ± 7 ng/mL; p < .001). Older age (age >50 years) (odds ratio [OR] = 3.2 [CI: 1.3-8.2]; p = .013), positive Helicobacter pylori serology (OR = 5.1 [CI: 1.4-17.8]; p = .012), presence of GS (OR = 5 [CI: 1.5-16.9]; p = .009) and detectable AAA levels (OR = 6.8 [CI: 1.3-35.7]; p = .024) were independent risk factors for the presence of the GBC among all study subjects. Among patients harboring GS, older age (age >50 years) (OR = 4.5 [CI: 1.3-14.9]; p = .015), female gender (OR = 3.8 [CI: 1.2-12.5]; p = .027), presence of multiple GS (OR = 21.9 [CI: 4.8-100.4]; p < .001) and high serum AAA levels (OR = 5.3 [CI: 1.6-17.3]; p = .006) were independent risk factors for the presence of the GBC. Elderly age >50 years (OR = 2.6 [CI: 1.3-5.2]; p = .010) and frequent peanut consumption (OR = 2.3 [CI: 1.1-4.9]; p = .030) were independent risk factors for high serum AAA levels. The current study has implications for the prevention of GBC through the reduction of dietary aflatoxin exposure.

Microcystin-leucine-arginine promotes the development of gallbladder carcinoma via regulating ELAC2

Gallbladder carcinoma (GBC) is the most prevalent cancer of the bile tract, with unexpected GBC accounting for almost half of all GBC cases in some tertiary medical centers. Although the involvement of microcystin-leucine-arginine (MC-LR) in the development of intrahepatic cholangiocarcinoma has been established, there is a paucity of data regarding its association with GBC. The present study aims to investigate whether MC-LR level in the gallbladder of patients is associated with GBC development and, if so, to characterize the underlying mechanism in GBC cells. Our clinical data revealed that MC-LR level was significantly increased in GBC patients compared to patients with gallbladder stones only (P = 0.009). Moreover, our findings demonstrated that MC-LR could promote the proliferation and metastasis of human GBC cell lines. Furthermore, ELAC2 was identified as a critical mRNA involved in GBC progression through RNA sequencing. Collectively, our study suggests that MC-LR might be involved in the development of GBC by modulating the expression of ELAC2.

Identification of Potential Hub Genes Related to Aflatoxin B1, Liver Fibrosis and Hepatocellular Carcinoma via Integrated Bioinformatics Analysis

The molecular mechanism of the hepatotoxicant aflatoxin B1 to induce liver fibrosis and hepatocellular carcinoma (HCC) remains unclear, to offer fresh perspectives on the molecular mechanisms underlying the onset and progression of AFB1-Fibrosis-HCC, which may offer novel targets for the detection and therapy of HCC caused by AFB1. In this study, expression profiles of AFB1, liver fibrosis and liver cancer-related datasets were downloaded from the Gene Expression Omnibus (GEO), and differentially expressed genes (DEGs) were identified by the GEO2R tool. The STRING database, CytoHubba, and Cytoscape software were used to create the protein-protein interaction and hub genes of the combined genes, and the ssGSEA score for inflammatory cells related gene sets, the signaling pathway, and immunotherapy were identified using R software and the GSEA database. The findings revealed that AFB1-associated liver fibrosis and HCC combined genes were linked to cell process disruptions, the BUB1B and RRM2 genes were identified as hub genes, and the BUB1B gene was significantly increased in JAK-STAT signaling gene sets pathways as well as having an immunotherapy-related impact. In conclusion, BUB1B and RRM2 were identified as potential biomarkers for AFB1-induced fibrosis and HCC progression.

Occurrence of Aflatoxins and Ochratoxin A during Merkén Pepper Powder Production in Chile

Berry fruits of Capsicum annuum L. cv. "Cacho de Cabra" are used for the manufacture of a traditional pepper powder known as Merkén. In the present study, aflatoxins (AFs) and ochratoxin A (OTA) contamination in berry fruits of C. annuum was determined at harvest, drying, and smoking stages of Merkén production, in cumin and coriander seeds used as Merkén ingredients, and in the final packaged Merkén produced by local farmers. Additionally, Merkén samples from local markets in the region of La Araucanía (Chile) were also evaluated. Chromatographic analysis was based on a qualitative method. AFs and OTA were not detected on pepper pods and seeds. There was no detection of AFs and OTA on cultured Aspergillus and Penicillium strains isolated from pepper pods, cumin and coriander seeds and Merkén. The lack of AFs/OTA-producers among the isolated fungal species can explain and support the absence of contamination in pepper pods. In contrast, the AFB₁ was detected in 75% of Merkén obtained from farmers and 46% of Merkén samples purchased from local markets; while OTA was detected in 100% of Merkén samples obtained from farmers and local markets. In the Merkén production chain, the harvest and post-harvest are key stages for fungal growth while the commercialization stage is highly susceptible to AFs and OTA contamination.

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.