Expression of toll-like receptors on human rectal adenocarcinoma cells

Mechanisms of colon toxicity induced by long-term perfluorooctanoic acid exposure in mice

Perfluorooctanoic acid (PFOA), a persistent organic pollutant known for its chemical stability, is widely dispersed in the environment, posing significant health risks to mammals through various exposure routes such as ingestion, inhalation, and dermal contact. In this study, mice were exposed to PFOA (0, 0.2, 2 mg/L) through drinking water for 180 days to investigate its toxic effects on the colon. We identified differentially expressed genes through RNA sequencing and validated the impact of PFOA on the expression of these genes in colon tissue. Our findings revealed that long-term exposure to PFOA caused inflammatory bowel disease (IBD)-like damage to the mouse colon. We found PFOA could induce damage to the intestinal barrier. Inhibition of the Wnt signaling pathway following PFOA exposure results in impaired stem cell function in the colon of mice. Furthermore, PFOA activated the PPAR signaling pathway, disrupting cellular lipid metabolism in colon tissues. Additionally, PFOA induced inflammatory responses in colon tissue, facilitating NLR family, pyrin domain containing 3 (NLRP3) inflammasome activation and cell apoptosis. This study offers a thorough understanding of the mechanisms responsible for the damage to mouse colon tissue resulting from long-term exposure to PFOA.

The role of microbiota in the development of colorectal cancer

Colorectal cancer is the third largest cancer in worldwide and has been proven to be closely related to the intestinal microbiota. Many reports and clinical studies have shown that intestinal microbial behavior may lead to pathological changes in the host intestines. The changes can be divided into epigenetic changes and carcinogenic changes at the gene level, which ultimately promote the production and development of colorectal cancer. This article reviews the pathways of microbial signaling in the intestinal epithelial barrier, the role of microbiota in inflammatory colorectal tumors, and typical microbial carcinogenesis. Finally, by gaining a deeper understanding of the intestinal microbiota, we hope to achieve the goal of treating colorectal cancer using current microbiota technologies, such as fecal microbiological transplantation.

TLR4 Polymorphisms and Expression in Solid Cancers

Toll-like receptors (TLRs) are a type of pattern-recognition receptor (PRR) that are part of the innate immune system known to recognize pathogen-associated molecular patterns and thereby play a crucial role in host immune response. Among the various known TLRs, TLR4 is one of the most extensively studied PRRs expressed by immune, certain nonimmune, and tumor cells. When TLR4 binds with the bacterial lipopolysaccharide, it induces production of proinflammatory cytokines, chemokines, and effector molecules as part of the immune response. Continuous exposure to pathogens and TLR4 signaling results in chronic inflammation that may further lead to malignant transformation. TLR4 is a highly polymorphic gene, and genetic variations are known to influence host immune response, leading to dysregulation of signaling pathway, which may affect an individual's susceptibility to various diseases, including cancer. Furthermore, TLR4 expression in different tumor types may also serve as a marker for tumor proliferation, differentiation, metastasis, prognosis, and patient survival. This review aims to summarize various reports related to TLR4 polymorphisms and expression patterns and their influences on different cancer types with a special focus on solid tumors.

Potential role of Toll-like receptor 2 expression and polymorphisms in colon cancer susceptibility in the Saudi Arabian population

Background

Inflammation is a fundamental factor that contributes to the development and progression of several types of cancer including colon cancer. Toll-like receptors (TLRs) and their signaling pathways have been reported to be associated with chronic inflammation and thereby induced cancer. Our aim was to investigate the expression and polymorphisms of TLR2 and their association with colon cancer.

Methods

Real-time PCR and immunohistochemistry were used to investigate TLR2 gene expression and to evaluate the potential risk of predisposition to colon cancer caused by three tagging single-nucleotide polymorphisms (SNPs) on TLR2, including rs3804100, rs4696480, and rs3804099. TaqMan assay was conducted on samples from 115 patients with colon cancer and 102 age- and sex-matched normal individuals.

Results

We found that, TLR2 was highly expressed in epithelial colon cancer cells and both TLR2 mRNA and protein levels, and significantly decreased in tumor tissues compared to normal tissues. Two of three TLR2 SNPs increased the risk of colon cancer. However, TLR2 rs3804099 increased the risk of colon cancer development by more than 3.8- and 5-fold in female patients and patients aged less than 57 years, respectively. The T allele of TLR2 rs3804100 showed a significant association with patients less than 57 years. In silico analysis of the TLR2 nucleotide substitution in SNP rs3804100 and rs3804099 determined that 67% and 70% probability of these single nucleotide variants alter splicing phenotypes, rs3804100 more specifically result on activating an additional splice site. Genotype and allele frequencies of rs4696480 were similar between the overall study populations. Thus, TLR2 rs4696480 appear to be not involved in colon cancer in our study population.

Conclusions

There was a significant link between innate immunity deregulation through disruption of the TLRs and potential development of colon cancer. These SNPs can be used as screening markers for predicting colon cancer risk earlier in life to implement necessary prevention.

Multiple Gene-Environment Interactions on the Angiogenesis Gene-Pathway Impact Rectal Cancer Risk and Survival

Characterization of gene-environment interactions (GEIs) in cancer is limited. We aimed at identifying GEIs in rectal cancer focusing on a relevant biologic process involving the angiogenesis pathway and relevant environmental exposures: cigarette smoking, alcohol consumption, and animal protein intake. We analyzed data from 747 rectal cancer cases and 956 controls from the Diet, Activity and Lifestyle as a Risk Factor for Rectal Cancer study. We applied a 3-step analysis approach: first, we searched for interactions among single nucleotide polymorphisms on the pathway genes; second, we searched for interactions among the genes, both steps using Logic regression; third, we examined the GEIs significant at the 5% level using logistic regression for cancer risk and Cox proportional hazards models for survival. Permutation-based test was used for multiple testing adjustment. We identified 8 significant GEIs associated with risk among 6 genes adjusting for multiple testing: TNF (OR = 1.85, 95% CI: 1.10, 3.11), TLR4 (OR = 2.34, 95% CI: 1.38, 3.98), and EGR2 (OR = 2.23, 95% CI: 1.04, 4.78) with smoking; IGF1R (OR = 1.69, 95% CI: 1.04, 2.72), TLR4 (OR = 2.10, 95% CI: 1.22, 3.60) and EGR2 (OR = 2.12, 95% CI: 1.01, 4.46) with alcohol; and PDGFB (OR = 1.75, 95% CI: 1.04, 2.92) and MMP1 (OR = 2.44, 95% CI: 1.24, 4.81) with protein. Five GEIs were associated with survival at the 5% significance level but not after multiple testing adjustment: CXCR1 (HR = 2.06, 95% CI: 1.13, 3.75) with smoking; and KDR (HR = 4.36, 95% CI: 1.62, 11.73), TLR2 (HR = 9.06, 95% CI: 1.14, 72.11), EGR2 (HR = 2.45, 95% CI: 1.42, 4.22), and EGFR (HR = 6.33, 95% CI: 1.95, 20.54) with protein. GEIs between angiogenesis genes and smoking, alcohol, and animal protein impact rectal cancer risk. Our results support the importance of considering the biologic hypothesis to characterize GEIs associated with cancer outcomes.

Human TLR gene family members are differentially expressed in patients with urothelial carcinoma of the bladder

PURPOSE

Toll-like receptors (TLRs) have an important role in the activation of both innate and adaptive immunity in response to pathogens and endogenous danger signals from damaged or dying cells. The aim of this study was to determine the relationship between urothelial carcinoma (UC) and TLR expression.

BASIC PROCEDURES

Real-time polymerase chain reaction evaluation was made of the messenger RNA expression of TLRs 1-10 in 24 UC samples and 46 nontumoral bladder tissue samples. The levels of proinflammatory cytokines (IL-1β, IL-6, and IL-8) in the urine samples were also determined with enzyme-linked immunosorbent assay.

MAIN FINDINGS

TLR2-7 and TLR10 expressions were significantly higher in UC than in the control group (P<0.05 for all comparisons). No concordance was found between matched tumor tissue and urine samples in terms of TLR expression. IL-1β, IL-6, and IL-8 levels were significantly higher in urine specimens of patients with UC (P = 0.033, P = 0.001, and P = 0.008, respectively).

PRINCIPAL CONCLUSIONS

The results of this study demonstrated that the TLR gene expression profiles reflect the heterogeneity within UC. These results might also prompt further investigation to better understand the role of the TLR gene family expression in the tumor progression of UC.

Profile of gene expression of TLR-signaling pathways in colorectal cancer tissues

Toll-like receptors (TLRs) are involved in transduction of molecular signals in immune process such as induction and regulation of immunity, production of cytokines, and recognition of specific molecular patterns on the surface of microorganisms, but also in cancer development—which was partially proven in previous studies. There is a lack of detailed research on differentiating levels of TLR expression in colorectal cancer at different stages of its advancement, so in our study we want to determine whether there is such a difference of TLRs and TLR-connected protein expression. In this study, 83 samples of colorectal adenocarcinoma (varying clinical degrees) and 40 slices of healthy colon tissue have been analyzed. The delivered material was subjected to homogenization and extraction of total RNA. The isolated RNA was subsequently purified and valued quantitatively and qualitatively. Quantification was performed using a spectrophotometer GeneQuant II. The RNA concentration in the tested samples was determined spectrophotometrically. A qualitative assessment was performed by performing electrophoresis on a 1% agarose gel stained with ethidium bromide. The expression profile of the genes encoding the TLRs was determined using oligonucleotide microarray HG-U133A. To determine the mRNA (messenger RNA), differentiate cancerous tissue from normal colon using PL-Grid Infrastructure. The results were analyzed statistically, taking a significance level P < 0.05. In the study were found three proteins, DUSP2, IFNγ, EIF4A1, associated with TLR system, that differentiate early stages of colorectal cancer of healthy tissue, moreover eleven, inter alia: vascular endothelial growth factor (VEGF), which differentiate high stage of cancer of healthy tissues. The results emphasize the role of pathways associated with TLR activation in the pathogenesis of colorectal cancer. In summary, molecular studies on the development of colorectal cancer will enable the introduction of minimally invasive genetic diagnosis of early forms of cancer. In addition, identification of new signaling pathways can provide the basis for developing new therapeutic methods.