Effect of cigarette smoke extract on mitochondrial heme-metabolism: An in vitro model of oral cancer progression

Connecting the dots: investigating the link between environmental, genetic, and epigenetic influences in metabolomic alterations in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) accounts for around 90% of all oral cancers and is the eighth most common cancer worldwide. Despite progress in managing OSCC, the overall prognosis remains poor, with a survival rate of around 50-60%, largely due to tumor size and recurrence. The challenges of late-stage diagnosis and limitations in current methods emphasize the urgent need for less invasive techniques to enable early detection and treatment, crucial for improving outcomes in this aggressive form of oral cancer. Research is currently aimed at unraveling tumor-specific metabolite profiles to identify candidate biomarkers as well as discover underlying pathways involved in the onset and progression of cancer that could be used as new targets for diagnostic and therapeutic purposes. Metabolomics is an advanced technological approach to identify metabolites in different sample types (biological fluids and tissues). Since OSCC promotes metabolic reprogramming influenced by a combination of genetic predisposition and environmental factors, including tobacco and alcohol consumption, and viral infections, the identification of distinct metabolites through screening may aid in the diagnosis of this condition. Moreover, studies have shown the use of metabolites during the catalysis of epigenetic modification, indicating a link between epigenetics and metabolism. In this review, we will focus on the link between environmental, genetic, and epigenetic influences in metabolomic alterations in OSCC. In addition, we will discuss therapeutic targets of tumor metabolism, which may prevent oral tumor growth, metastasis, and drug resistance.

Decoding Oral Carcinogenesis and Tumor Progression in Whole Cigarette Smoke Exposure: A Systematic Review

This systematic review aims to highlight the molecular mechanisms by which whole cigarette smoke affects oral carcinogenesis and its progression in human oral cells, based on evidence from original research articles published in the literature. A literature search was conducted using three databases: Web of Science, Scopus, and PubMed from May to June 2024. The articles were screened, and the data were extracted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines (2020). The included studies were subsequently evaluated using the Systematic Review Center for Laboratory Animal Experimentation (SYRCLE) tool for bias factors. From the 14 included studies, two types of cell lines were frequently utilized: human oral mucosal epithelial cells or oral squamous cell carcinoma cells. In these cell lines, one of three forms of exposure was applied: cigarette smoke, its extract, or condensate. The mechanism of oral carcinogenesis and tumor progression includes aberrations in the heme metabolic pathway, modulation of miRNA-145, NOD1 and BiP expression, MMP-2, MMP-9, and cathepsin modulation, abnormal TSPO binding, RIP2-mediated NF-κB activation, MZF1-mediated VEGF binding, and activation of the RAGE signaling pathway. In conclusion, cigarette smoke significantly influences the development and progression of oral squamous cell carcinoma, based on the evidence highlighted in human oral cells. While previous studies have focused on specific carcinogens and pathways, this review added to our understanding of the overall impact of whole cigarette smoke on oral carcinogenesis at the molecular and cellular levels.

Potential Utilisation of Theobroma cacao Pod Husk Extract: Protective Capability Evaluation Against Pollution Models and Formulation into Niosomes

Theobroma cacao L. beans have long been used for food and medicinal purposes. However, up to 52%-76% of Theobroma cacao L. fruit comprises its husk, which are regarded as waste and oftentimes thrown away. In fact, cocoa pod husks actually possess a high antioxidant capacity. Antioxidants can be used to fight free radicals that are produced by environmental pollution. In order to simulate the effects of pollution, H2O2 and cigarette smoke extract models were used respectively. However, the antioxidant properties are limited on the skin due to poor penetration. Hence, in order to increase the topical penetration, cocoa pod husk extract (CPHE) was also formulated into niosomes thereafter. CPHE was characterised using total phenolic content, total flavonoid content and three antioxidant assays. After that, cytotoxicity and cytoprotective assay were conducted on HaCaT cells, which represent the skin epidermis. CPHE was then formulated into niosomes subjected to stability and penetration studies for three months. CPHE was shown to contain 164.26 ± 1.067 mg GAE/g extract in total phenolic content and 10.72 ± 0.32 mg QCE/g extract in total flavonoid content. In addition, our results showed that CPHE possesses similar antioxidant capacity through 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, around eight-fold less through ABTS assay and approximately twelve-fold less through Ferric reducing power (FRAP) assay. The extract also showed comparable cytoprotective properties to that of standard (ascorbic acid). The niosome formulation was also able to increase the penetration compared to unencapsulated extract, as well as possess a good stability profile. This showed that CPHE, in fact, could be repurposed for other uses other than being thrown away as waste.

Heme Metabolism Mediates the Effects of Smoking on Gut Microbiome

INTRODUCTION

The number of smokers worldwide increased greatly during the past decades and reached 1.14 billion in 2019, becoming a leading risk factor for human health. Tobacco smoking has wide effects on human genetics, epigenetics, transcriptome, and gut microbiome. Although many studies have revealed effects of smoking on host transcriptome, research on the relationship between smoking, host gene expression, and the gut microbiome is limited.

AIMS AND METHODS

We first explored transcriptome and metagenome profile differences between smokers and nonsmokers. To evaluate the relationship between host gene expression and gut microbiome, we then applied bidirectional mediation analysis to infer causal relationships between smoking, gene expression, and gut microbes.

RESULTS

Metagenome and transcriptome analyses revealed 71 differential species and 324 differential expressed genes between smokers and nonsmokers. With smoking as an exposure variable, we identified 272 significant causal relationships between gene expression and gut microbes, among which there were 247 genes that mediate the effect of smoking on gut microbes. Pathway-based enrichment analysis showed that these genes were significantly enriched in heme metabolic pathway, which mainly mediated the changes of Bacteroides finegoldii and Lachnospiraceae bacterium 9_1_43BFAA. Additionally, by performing metabolome data analysis in the Integrated Human Microbiome Project (iHMP) database, we verified the correlation between the intermediate products of the heme metabolism pathway (porphobilinogen, bilirubin, and biliverdin) and gut microbiome.

CONCLUSIONS

By investigating the bidirectional interaction between smoking-related host gene expression and gut microbes, this study provided evidence for the mediation of smoking on gut microbes through co-involvement or interaction of heme metabolism.

IMPLICATIONS

By comparing the metagenome and transcriptome sequencing profiles between 34 smokers and 33 age- and gender-matched nonsmokers, we are the first to reveal causal relationships among tobacco smoking, host gene expression, and gut microbes. These findings offer insight into how smoking affects gut microbes through host gene expression and metabolism, which highlights the importance of heme metabolism in modulating the effects of smoking on gut microbiome.

Development and validation of a CTNNB1-associated metabolic prognostic model for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a heterogeneous malignancy closely related to metabolic reprogramming. We investigated how CTNNB1 mutation regulates the HCC metabolic phenotype and thus affects the prognosis of HCC. We obtained the mRNA expression profiles and clinicopathological data from The Cancer Genome Atlas (TCGA), the International Cancer Genomics Consortium (ICGC) and the Gene Expression Omnibus database (GSE14520 and GSE116174). We conducted gene set enrichment analysis on HCC patients with and without mutant CTNNB1 through TCGA dataset. The Kaplan‐Meier analysis and univariate Cox regression analysis assisted in screening metabolic genes related to prognosis, and the prognosis model was constructed using the Lasso and multivariate Cox regression analysis. The prognostic model showed good prediction performance in both the training cohort (TCGA) and the validation cohorts (ICGC, GSE14520, GSE116174), and the high‐risk group presented obviously poorer overall survival compared with low‐risk group. Cox regression analysis indicated that the risk score can be used as an independent predictor for the overall survival of HCC. The immune infiltration in different risk groups was also evaluated in this study to explore underlying mechanisms. This study is also the first to describe an metabolic prognostic model associated with CTNNB1 mutations and could be implemented for determining the prognoses of individual patients in clinical practice.

Role of Reactive Oxygen Species in Cancer Progression: Molecular Mechanisms and Recent Advancements

Reactive oxygen species (ROS) play a pivotal role in biological processes and continuous ROS production in normal cells is controlled by the appropriate regulation between the silver lining of low and high ROS concentration mediated effects. Interestingly, ROS also dynamically influences the tumor microenvironment and is known to initiate cancer angiogenesis, metastasis, and survival at different concentrations. At moderate concentration, ROS activates the cancer cell survival signaling cascade involving mitogen-activated protein kinase/extracellular signal-regulated protein kinases 1/2 (MAPK/ERK1/2), p38, c-Jun N-terminal kinase (JNK), and phosphoinositide-3-kinase/ protein kinase B (PI3K/Akt), which in turn activate the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), matrix metalloproteinases (MMPs), and vascular endothelial growth factor (VEGF). At high concentrations, ROS can cause cancer cell apoptosis. Hence, it critically depends upon the ROS levels, to either augment tumorigenesis or lead to apoptosis. The major issue is targeting the dual actions of ROS effectively with respect to the concentration bias, which needs to be monitored carefully to impede tumor angiogenesis and metastasis for ROS to serve as potential therapeutic targets exogenously/endogenously. Overall, additional research is required to comprehend the potential of ROS as an effective anti-tumor modality and therapeutic target for treating malignancies.

Cigarette smoking promotes cancer-related transformation of oral epithelial cells through activation of Wnt and MAPK pathway

Aim: Study aims to investigate the effect of cigarette smoking on cancer-related transformation in oral epithelial cells of smokers through evaluating the alteration in Wnt/β-catenin and MAPK pathways. Materials & methods: Exfoliated oral epithelial cells were collected from 138 subjects and categorized into nonsmokers, smokers and clinically diagnosed precancer and cancer patients. Real-time quantitative PCR was performed to detect the fold changes of related genes. Expressions of biomarkers were assessed using immunofluorescence and western blot. Results: Study shows significant (p < 0.001) alteration in mRNA level of TNF-α, NF-κβ, FZD1, β-catenin, PARD 3, MAPK1 and vimentin genes under cigarette smoking. Conclusion: Results suggested the progression of oral cancer under cigarette smoking occurs through multiple events and activation of canonical Wnt/MAPK pathways.