Role of Toll like receptor in progression and suppression of oral squamous cell carcinoma

FGFR2 and miR-889-3p expression in oral cancer is associated with cervical lymph node metastasis

OBJECTIVE

Fibroblast growth factor receptor-2 (FGFR2) and miR-889-3p expression in oral squamous cell carcinoma (OSCC) tumours were compared to normal controls. We then examined the relationship between miR-889-3p, FGFR2 expression and patient clinicopathological features.

MATERIALS AND METHODS

The interaction of FGFR2 and miR-889-3p was investigated using bioinformatics. Then, OSCC tumour biopsies and normal gingiva were collected and processed for expression analysis of FGFR2-specific mRNA and miR-889-3p using real-time PCR. Immunohistochemistry evaluated the expression of the FGFR2 protein.

RESULTS

The protein and mRNA expression levels of FGFR2 were significantly greater in tumours when contrasted with controls. Expression of miR-889-3p was significantly lower in OSCC compared to normal tissues. The FGFR2 and miR-889-3p expressions were inversely related (-0.86 and -0.73, respectively) in both cases and controls. Changes in miR-889-3p and FGFR2 expression in tumour tissues were associated with lymph node metastasis (LNM), with ~0.57 and ~3.0 folds of change in positive-LNM patients, respectively.

CONCLUSION

Decreased expression of miR-889-3p in OSCC tumours suggests that miR-889-3p functions as a tumour suppressor gene. Overexpression of FGFR2 further proves the role of miR-889-3p in the regulation of the FGFR2 pathway. This was further confirmed by showing differences in miR-889-3p expression in positive and negative LNM cases.

Impact of TLR9 and TLR7 gene polymorphisms on prognosis and survival of patients with oral squamous cell carcinoma

Despite significant efforts in developing new diagnostic and therapeutic modalities, oral squamous cell carcinomas (OSCCs) still exhibit a high recurrence rate, a low five-year survival rate, and an increasing prevalence. Toll-like receptors (TLRs), which initiate and perpetuate immune mechanisms upon activation, have been linked to immune surveillance and the antitumor immune response. The aim of this study was to investigate the association between the polymorphisms of the TLR7 rs3853839 and TLR9 rs187084 genes and OSCC risk, clinicopathological features, and survival. Genotyping was assessed by real-time polymerase chain reaction (PCR) in 95 HPV negative OSCC patients and 107 age- and sex-matched healthy controls. Patients with lymph node metastases had higher frequencies of the TLR9 rs187084 CC variant genotype compared to the major TT genotype (P = 0.020) and to T-allele carriers (combined TT + CT genotypes, P = 0.015). A higher prevalence of advanced stage III was observed in patients with the TLR9 rs187084 variant CC genotype compared to TT (P = 0.047) and to T-allele carriers (TT + CT, P = 0.037). Kaplan-Meier analysis revealed a lower overall survival (OS) rate in patients with the TLR9 rs187084 variant CC genotype compared to the TT genotype (P = 0.010, log-rank test) and to T-allele carriers (TT + CT genotypes, P = 0.002), though it was not an independent predictor of OS. Both TLR9 rs187084 and TLR7 rs3853839 polymorphisms were associated with high alcohol consumption (P = 0.027 and P = 0.001, respectively). The investigated genetic variations were not associated with OSCC susceptibility. The variant CC genotype of the TLR9 rs187084 polymorphism might be a marker of poor survival and tumor progression in OSCC.

Immunoexpression pattern of TLR3 and TLR7 in minor salivary gland adenoid cystic carcinoma and its role in prognosis

OBJECTIVES

Adenoid cystic carcinoma (ACC) of the salivary glands has poor long-term prognosis and a high metastatic rate. Toll-like receptors (TLRs), first-line immune activators, have been associated with both tumor progression and suppression. We aimed to study TLR3 and TLR7 behavior in ACC.

MATERIALS AND METHODS

We studied TLR3 and TLR7 immunoexpression of 46 minor salivary gland ACCs diagnosed at the Department of Otorhinolaryngology - Head and Neck Surgery, Helsinki University Hospital, Helsinki, Finland over the period 1974-2012. The associations of TLR3 and TLR7 immunoexpression with clinicopathological factors were evaluated by χ2-test and Fisher's exact test.

RESULTS

In the majority of samples, both TLR3 and TLR7 were immunoexpressed in cytoplasm. The immunoexpression was heterogeneous between individual tumors. Stronger TLR7 immunoexpression associated with recurrence rate and poorer disease-specific survival (DSS). TLR3 did not associate significantly with survival although we found an inverse correlation between TLR3 and TLR7 immunopositivity. Hence, when TLR3 immunoexpression was negative or mild, TLR7 immunoexpression was moderate to strong, and vice versa.

CONCLUSIONS

TLR3 and TLR7 are immunoexpressed in minor salivary gland ACC. TLR7 is potentially an independent prognostic marker for recurrence rate and DSS.

Role of toll-like receptor in the pathogenesis of oral cancer

Toll-like receptors are important molecules of innate immunity. They are known as pattern recognition receptors. They recognise certain molecules known as pathogen-associated molecular pattern on a pathogen and release chemicals that causes inflammation. Toll-like receptors (TLR) help in the removal of the infected cell and thus stop the spread of infection and are being studied for their association with cancer. Oral carcinoma has emerged as a major problem of our country today; it is found ranks first in men and third in women. Toll-like receptors have been implicated in the development of cancer. Certain polymorphisms in toll-like receptor can make a cell more susceptible to develop oral cancer. The identification of toll-like receptors and the different genotypes that are involved in the development of cancer can be utilised for using them as biomarkers of the disease. The study revealed that toll-like receptors like TLR7 and TLR5 are found to have a role in suppression of oral cancer while toll-like receptors like TLR4 and TLR2 are found to be associated with the progression of oral cancer. Toll-like receptors can turn out as important target molecules in the future in designing therapeutic strategies for oral cancer.

Genetic Association of Toll-Like Receptor 4 (TLR4) Gene Polymorphism (rs4986790) With Oral Squamous Cell Carcinoma (OSCC): A Pilot Case-Control Study

Introduction Oral squamous cell carcinoma (OSCC) is a highly prevalent and most common form of oral malignancy in the Indian population. Toll-like receptors belong to an important family of receptors that are involved in the process of pathogen recognition and mounting immune response. The expression of this receptor is dysregulated on the tumor cells as reported across several cancer types. The genetic variants in this gene could have a profound impact on the expression of the Toll-like receptor 4 (TLR4) gene.  Objective This study aimed to understand the association of TLR4 gene polymorphism (rs4986790) with OSCC. The objective of this study was to compare the allele and genotype frequencies between the two groups, viz., OSCC and normal healthy subjects, recruited in the study. Materials and methods The blood samples were collected from normal healthy subjects (N = 25) and OSCC patients (N = 25). Genomic DNA was isolated from all samples, and genotyping was performed for the TLR4 gene polymorphism (rs4986790) employing the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) approach. The frequency distribution of genotypes and alleles across the study groups was determined by the Chi-square test.  Results The allele frequency for TLR4 gene polymorphism (rs4986790) in the case group was found to be 60% (A allele) and 40% (G allele), respectively. The study population in both groups were found to agree with the Hardy-Weinberg equilibrium (HWE). The genotype frequency did not differ significantly among the two study groups which was evident from the p-value = 0.8285.  Conclusion The present study did not report any significant association of the TLR4 polymorphic marker rs4986790 with OSCC. Further investigations into the association of other polymorphic markers in the TLR4 gene, among the larger population of OSCC patients, could provide evidence of their association with OSCC.

Oral tumor heterogeneity, its implications for patient monitoring and designing anti-cancer strategies

Oral cancer tumors occur in the mouth and are mainly derived from oral mucosa linings. It is one of the most common and fatal malignant diseases worldwide. The intratumor heterogeneity (ITH) of oral cancerous tumor is vast, so it is challenging to study and interpret. Due to environmental selection pressures, ITH arises through diverse genetic, epigenetic, and metabolic alterations. The ITH also talks about peri-tumoral vascular/ lymphatic growth, perineural permeation, tumor necrosis, invasion, and clonal expansion/ the coexistence of multiple subclones in a single tumor. The heterogeneity offers tumors the adaptability to survive, induce growth/ metastasis, and, most importantly, escape antitumor therapy. Unfortunately, the ITH is prioritized less in determining disease pathology than the traditional TNM classifications or tumor grade. Understanding ITH is challenging, but with the advancement of technology, this ITH can be decoded. Tumor genomics, proteomics, metabolomics, and other modern analyses can provide vast information. This information in clinics can assist in understanding a tumor's severity and be used for diagnostic, prognostic, and therapeutic decision-making. Lastly, the oral tumor ITH can lead to individualized, targeted therapy strategies fighting against OC.

Toll-like receptor-guided therapeutic intervention of human cancers: molecular and immunological perspectives

Toll-like receptors (TLRs) serve as the body's first line of defense, recognizing both pathogen-expressed molecules and host-derived molecules released from damaged or dying cells. The wide distribution of different cell types, ranging from epithelial to immune cells, highlights the crucial roles of TLRs in linking innate and adaptive immunity. Upon stimulation, TLRs binding mediates the expression of several adapter proteins and downstream kinases, that lead to the induction of several other signaling molecules such as key pro-inflammatory mediators. Indeed, extraordinary progress in immunobiological research has suggested that TLRs could represent promising targets for the therapeutic intervention of inflammation-associated diseases, autoimmune diseases, microbial infections as well as human cancers. So far, for the prevention and possible treatment of inflammatory diseases, various TLR antagonists/inhibitors have shown to be efficacious at several stages from pre-clinical evaluation to clinical trials. Therefore, the fascinating role of TLRs in modulating the human immune responses at innate as well as adaptive levels directed the scientists to opt for these immune sensor proteins as suitable targets for developing chemotherapeutics and immunotherapeutics against cancer. Hitherto, several TLR-targeting small molecules (e.g., Pam3CSK4, Poly (I:C), Poly (A:U)), chemical compounds, phytocompounds (e.g., Curcumin), peptides, and antibodies have been found to confer protection against several types of cancers. However, administration of inappropriate doses of such TLR-modulating therapeutics or a wrong infusion administration is reported to induce detrimental outcomes. This review summarizes the current findings on the molecular and structural biology of TLRs and gives an overview of the potency and promises of TLR-directed therapeutic strategies against cancers by discussing the findings from established and pipeline discoveries.

Cytokines secreted by inflamed oral mucosa: implications for oral cancer progression

The oral mucosa has an essential role in protecting against physical, microbial, and chemical harm. Compromise of this barrier triggers a wound healing response. Key events in this response such as immune infiltration, re-epithelialization, and stroma remodeling are coordinated by cytokines that promote cellular migration, invasion, and proliferation. Cytokine-mediated cellular invasion and migration are also essential features in cancer dissemination. Therefore, exploration of cytokines that regulate each stage of oral wound healing will provide insights about cytokines that are exploited by oral squamous cell carcinoma (SCC) to promote tumor development and progression. This will aid in identifying potential therapeutic targets to constrain SCC recurrence and increase patient survival. In this review, we discuss cytokines that overlap in oral wounds and SCC, emphasizing how these cytokines promote cancer progression.

Polymorphisms and haplotypes of TLR-4/9 associated with bacterial infection, gingival inflammation/recession and oral cancer

BACKGROUND

The expression and SNPs of innate immunity genes TLR-4/9 for bacterial infection, gingival inflammation/gingival recession (GIGR), and oral squamous cell carcinoma (OSCC) are largely unknown.

PATIENTS AND METHOD

235 specimens (120 OSCC cases, among which 85 cases with either Porphyromonas gingivalis, Fusobacterium nucleatum or Treponema denticola infection and GIGR) and 115 healthy controls were used to know the expression and polymorphisms (TLR-4: N1:rs10759931, N2:rs11536889, N3:rs1927911, N4:rs4986790; TLR-9: N5:rs5743836, N6:rs352140, N7:rs187084 and N8:rs352139) of TLR-4/9 by western blot, RT-PCR, and allele-specific (AS)-PCR followed by sequencing.

RESULTS

Increased TLR-4/9 mRNA/protein expression, bacterial infection (BI) and GIGR were associated with OSCC incidence. One of the three BI and GIGR was observed in 70.83% of OSCC cases, whereas all the HC used were free from any of these three BI/GIGR. The N3: CT-genotype (Odds Ratio hereafter as O.R.=1.811, p = 0.0338), TT-genotype (O.R.=3.094, p = 0.0124), 'T'-allele (O.R.=1.821, p = 0.003), N4: AG-genotype (O.R.=2.015, p = 0.0222) and 'G'-allele (O.R.=1.86, p = 0.018) of TLR-4 as well as the N5: CC-genotype (O.R.=3.939, p = 0.0017), 'C'-allele (O.R.=1.839, p = 0.0042), N6: AA-genotype (O.R.=2.195, p = 0.0234), 'A'-allele (O.R.=1.569, p = 0.0163), N7: TC-genotype (O.R.=2.083, p = 0.0136), CC-genotype (O.R.=2.984, p = 0.003) and 'C'-allele (O.R.=1.885, p = 0.0008) of TLR-9 were associated with increased OSCC risk. Similarly, the N2:'C'-allele (O.R.=1.615, p = 0.0382), N3: TT-genotype (O.R.=2.829, p = 0.0336), 'T'-allele (O.R.=1.742, p = 0.0115), N4: AG-genotype (O.R.=2.221, p = 0.0147) and 'G'-allele (O.R.=1.890, p = 0.0238) of TLR-4 as well as the N5: CC-genotype (O.R.=2.830, p = 0.031), N6: AA-genotype (O.R.=2.6, p = 0.0122) and 'A'-allele (O.R.=1.746, p = 0.0064), N7:CC-genotype (O.R.2.706, p = 0.0111) and 'C'-allele (O.R. 1.774, p = 0.0055) of TLR-9 were correlated with GIGR and BI. TLR-4 (N1-N2-N3-N4: A-C-T-A (O.R.=2.1, p = 0.0069) and TLR-9 (N5-N6-N7-N8: T-A-C-A (O.R.=2.019, p = 0.0263); C-A-C-A (O.R.=6.0, p = 0.0084); C-A-C-G (O.R.=4.957, p = 0.0452) haplotypes were linked with OSCC vulnerability, while the TLR-4 (N1-N2-N3-N4: G-C-C-A (O.R.=0.5752, p = 0.0131) and TLR-9 (N5-N6-N7-N8: T-G-T-A (O.R.=0.5438, p = 0.0314); T-G-T-G (O.R.=0.5241, p = 0.036) haplotypes offered protection.

CONCLUSION

TLR-4/9 expression, polymorphisms, and BI-induced GIGR could increase OSCC risk. This may be used in pathogenesis and oral cancer prediction.

Association between Tissue Expression of Toll-Like Receptor and Some Clinicopathological Indices in Oral Squamous Cell Carcinoma

BACKGROUND

The oral squamous cell carcinoma (OSCC) composes about 90% of all head and neck cancers. The toll-like receptor (TLR)⁺ immune cells have potential of invasion and malignancy transformation. The aim of this study was assessment of possible associations between clinicopathological indices and TLR2 and TLR9 gene expression in OSCC.

METHODS

Forty-two OSCC samples with related healthy margins including 25 early and 17 advanced stages were gathered. The samples were classified histologically from grade I to II. The expression of TLR2 and TLR2 was evaluated by Real-time PCR. The patient's disease-free survival (DFS) and overall survival (OS) were analyzed using SPSS V.23 software.

RESULTS

The expression of TLR2 and TLR9 genes in tumor tissues (especially in grade I and II) were higher than healthy surgical margin tissue (p< 0.001). TLR9 expression in grade II was statistically significant than grade I in tumor tissue (p< 0.001). TLR9 expression in advanced stage was statistically significant in compare to early stage (p= 0.012). In advanced stage both overall survival (p= 0.029) and disease-free survival (p= 0.012) were statistically lower than early stage. The follow-up time to recurrence in advanced stage was statistically lower than early stage (p= 0.007).

CONCLUSION

Overexpression of TLRs 2, 9 play role in the pathogenesis and tumor development of OSCC and can be applied as biomarker in prognostic approaches.

Protein overexpression of toll-like receptor 4 and myeloid differentiation factor 88 in oral squamous cell carcinoma and clinical significance

Oral squamous cell carcinoma (OSCC) is the most common type of malignancy of the head and neck. In the present study, the expression of Toll-like receptor 4 (TLR4) and myeloid differentiation primary response gene 88 (MyD88) was evaluated in 55 OSCC tissues and their corresponding adjacent tissues using immunohistochemistry and reverse-transcription quantitative PCR. The results indicated that TLR4 and MyD88 were overexpressed in OSCC. Furthermore, high expression of MyD88 was negatively associated with a poor degree of differentiation, recurrence and metastasis of the tumor and was positively associated with underlying disease, including hypertension, heart disease and diabetes mellitus. Furthermore, high expression of TLR4 was positively associated with a long growth time of the tumor. In conclusion, the present study evaluated the expression levels of TLR4 and MyD88 in OSCC, as well as the association between them and clinicopathological factors, to provide markers for the prognosis and treatment of OSCC. These two genes may serve as biomarkers to optimize OSCC treatment, setting a new direction for stratifying patients and developing precise and personalized treatment regimens; the TLR4/MyD88 pathway may serve as a potential therapeutic target in the future.