Detection of Deregulated Pathways to Lymphatic Metastasis in Oral Squamous Cell Carcinoma

Comprehensive Analysis of Tumor Immune Microenvironment Characteristics for the Prognostic Prediction and Immunotherapy of Oral Squamous Cell Carcinoma

Background: Oral squamous cell carcinoma (OSCC) is the most common cancer of oral and maxillofacial region. A recent clinical research has shown that tumor immune microenvironment (TIME)cells are closely related to immunotherapy sensitivity and OSCC prognosis. Nonetheless, a comprehensive analysis of TIME in OSCC has not been reported.

Methods: Bioinformatics and computational algorithms were employed to determine the significance of TIME cells in 257 OSCC patients. TIME scores were measured by three TIME models, and then used to evaluate the prognosis of OSCC patients.

Results: High TIME score was characterized by better prognosis in OSCC patients less than 60 years old, overexpression of immunotherapy targets (e.g., PD-1 and CLTA-4), and higher T-cell activity to inhibit tumor growth. Besides, poor prognosis was associated with low time score.

Conclusion: TIME score exhibited potential as a prognostic biomarker and an indicator in predict immunotherapeutic outcomes. Through the understanding of TIME model, this study can provide a better scheme for immunotherapy as the effective treatment of OSCC patients in the future.

CNV Analysis of the Correlation between Preoperative Lymph Node Metastasis and Prognosis of Early Tongue Cancer

Objective: To investigate the relationship between preoperative concealed lymph node metastasis (LNM) and prognosis in patients with early tongue cancer.

Methods: According to preoperative lymph node dissection, 41 patients with tongue cancer were divided into the LNM group (n=19) and the non-LNM group (n=22). Analysis of single nucleotide variation (SNV), tumor mutation burden (TMB), mutant allele tumor heterogeneity (MATH), aneuploidy and copy number variation (CNV) was performed to identify differentially expressed genes (DEGs) related to LNM. While KEGG analysis was conducted to reveal the CNV differentially expressed genes and main enriched pathways, the correlation between pathways and genes was analyzed by hierarchical clustering. The clinical information of LNM and data on overall survival (OS) rate were obtained from The Cancer Genome Atlas (TCGA), and survival analysis was performed based on combined LNM information.

Results: We observed significant correlations for the mTOR signaling pathway, Hippo signaling pathway and Wnt signaling pathway with the LNM group, while leukocyte transendothelial migration and cytokine-cytokine receptor interaction were markedly correlated with the non-LNM group. Moreover, TNFRSF10C was identified as the main DEG in the leukocyte transendothelial migration pathway. TCGA-based validation revealed that the disease-free survival (DFS) of the non-LNM group was significantly higher than that of the LNM group (P<0.005) when TNFRSF10C CNV was set to a log2 ratio>-0.163.

Conclusion: The differential expression of TNFRSF10C in leukocyte transendothelial migration, an immune-related pathway, is associated with LNM and DFS. The TNFRSF10C CNV log2 ratio could potentially serve as an indicator of good prognosis for tongue cancer patients with non-LNM after neck dissection.

Epigenomic dysregulation-mediated alterations of key biological pathways and tumor immune evasion are hallmarks of gingivo-buccal oral cancer

BACKGROUND

Gingivo-buccal oral squamous cell carcinoma (OSCC-GB) is the most common cancer among men in India and is associated with high mortality. Although OSCC-GB is known to be quite different from tongue cancer in its genomic presentation and its clinical behavior, it is treated identically as tongue cancer. Predictive markers of prognosis and therapy that are specific to OSCC-GB are, therefore, required. Although genomic drivers of OSCC-GB have been identified by whole exome and whole genome sequencing, no epigenome-wide study has been conducted in OSCC-GB; our study has filled this gap, and has discovered and validated epigenomic hallmarks of gingivobuccal oral cancer.

METHODS

We have carried out integrative analysis of epigenomic (n = 87) and transcriptomic (n = 72) profiles of paired tumor-normal tissues collected from OSCC-GB patients from India. Genome-wide DNA methylation assays and RNA-sequencing were performed on high-throughput platforms (Illumina) using a half-sample of randomly selected patients to discover significantly differentially methylated probes (DMPs), which were validated on the remaining half-sample of patients.

RESULTS

About 200 genes showed significant inverse correlation between promoter methylation and expression, of which the most significant genes included genes that act as transcription factors and genes associated with other cancer types. Novel findings of this study include identification of (a) potential immunosuppressive effect in OSCC-GB due to significant promoter hypomethylation driven upregulation of CD274 and CD80, (b) significant dysregulation by epigenetic modification of DNMT3B (upregulation) and TET1 (downregulation); and (c) known drugs that can reverse the direction of dysregulation of gene expression caused by promoter methylation.

CONCLUSIONS

In OSCC-GB patients, there are significant alterations in expression of key genes that (a) regulate normal cell division by maintenance of balanced DNA methylation and transcription process, (b) maintain normal physiological signaling (PPAR, B cell receptor) and metabolism (arachidonic acid) pathways, and (c) provide immune protection against antigens, including tumor cells. These findings indicate novel therapeutic targets, including immunotherapeutic, for treatment of OSCC-GB.

miR‑148a modulates the viability, migration and invasion of oral squamous cell carcinoma cells by regulating HLA‑G expression

Oral squamous cell carcinoma (OSCC) is a common malignancy of the oral and maxillofacial regions. MicroRNAs (miRs) are a group of endogenous small noncoding RNAs that inhibit gene expression by binding to the mRNA of target genes, and serve important roles in numerous biological processes. Reverse transcription-quantitative polymerase chain reaction and western blotting were used to detect gene and protein expression levels, respectively. Cell proliferation, migration and invasion were detected using MTT, wound healing and Matrigel assays, respectively. The association between miR-148a and human leukocyte antigen-G (HLA-G) was analyzed using Targetscan and Luciferase reporter assays. In the present study, miR-148a was revealed to be significantly downregulated in OSCC cells. To further investigate the functions of miR-148a in OSCC, the viability, migration, and invasive abilities of SCC-9 cells were investigated following transfection with miR-148a mimics or miR-148a inhibitor. It was revealed that transfection with miR-148a mimics significantly reduced the viability, migration and invasion of cells, whereas miR-148a inhibitor significantly enhanced these properties. In addition, HLA-G was identified as a direct target of miR-148a and demonstrated to be downregulated in OSCC cells. Furthermore, it was revealed that transfection with miR-148a mimics decreased the expression levels of HLA-G mRNA and protein in SCC-9 cells, whereas transfection with miR-148a inhibitor increased the expression of HLA-G mRNA and protein. The results indicated that there was an association between miR-148a and HLA-G expression, and suggested that miR-148a may be a potential target in the treatment of OSCC.

Combined Expression of c-jun, c-fos, and p53 Improves Estimation of Prognosis in Oral Squamous Cell Carcinoma

To identify the prognostic value of c-jun, c-fos, and p53 in oral cancer, we examined the impact of immunohistochemical expression of these markers on tumor progression in 157 oral squamous cell carcinoma (OSCC). We found that c-jun or c-fos was significantly associated with lymph node metastasis, and coexpression of c-jun/c-fos, or c-jun/c-fos/p53 were significantly associated with lymph node metastasis, poor differentiation and clinical stage. The coexpression of c-jun/c-fos/p53 was identified as independent prognostic factors for overall survival. Simultaneous coexpression of these markers in OSCCs might prove to be a useful indicator for differentiation of low and high-risk patients.

Annexin A1 attenuates EMT and metastatic potential in breast cancer

Metastasis is the major cause of carcinoma-induced death, but mechanisms involved are poorly understood. Metastasis crucially involves epithelial-to-mesenchymal transition (EMT), causing loss of epithelial polarity. Here we identify Annexin A1 (AnxA1), a protein with important functions in intracellular vesicle trafficking, as an efficient suppressor of EMT and metastasis in breast cancer. AnxA1 levels were strongly reduced in EMT of mammary epithelial cells, in metastatic murine and human cell lines and in metastatic mouse and human carcinomas. RNAi-mediated AnxA1 knockdown cooperated with oncogenic Ras to induce TGFβ-independent EMT and metastasis in non-metastatic cells. Strikingly, forced AnxA1 expression in metastatic mouse and human mammary carcinoma cells reversed EMT and abolished metastasis. AnxA1 knockdown stimulated multiple signalling pathways but only Tyk2/Stat3 and Erk1/2 signalling were essential for EMT.

The association between hypoxia inducible factor-1alpha gene polymorphisms and increased susceptibility to oral cancer

The aim of this study was to estimate the relations between hypoxia inducible factor-1alpha (HIF-1alpha) gene polymorphisms, C1772T and G1790A, to the susceptibility and clinicopathological status of oral cancer. A total of 521 subjects, including 347 controls and 174 oral cancer patients, were recruited in this study and subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to analyze the impact of these two polymorphic variants on oral cancer. A significant association between oral cancer susceptibility and G1790A polymorphism was demonstrated since individuals with heterozygotes, that is GA, had a higher risk for oral cancer, compared to GG genotypes after adjusting for other confounders (AOR=3.31; 95%CI=1.27-8.61). Compared to individuals with both C1772C and G1790G homozygotes, individuals with at least one of either C1772T or G1790A of HIF-1alpha gene had a risk of 2.17-folds (95% CI=1.0-4.75) to develop oral cancer. Moreover, results also revealed the presence of synergistic effect between gene polymorphisms of HIF-1alpha and environmental risk factors, such as tobacco and betel nut consumptions while there was no significant association between HIF-1alpha gene polymorphism and clinicopathological parameters of oral cancer. Genetic polymorphism, including C1772T and G1790A, of HIF-1alpha is an important factor for the susceptibility to oral cancer.