Loss of epithelial markers is an early event in oral dysplasia and is observed within the safety margin of dysplastic and T1 OSCC biopsies

Exogenous BMI1 expression aggravates oral squamous cell carcinomas in tongue epithelia

Oral squamous cell carcinoma (OSCC) is characterized by aggressiveness and a poor prognosis, in part because most patients are diagnosed during the later stages of the disease. B cell-specific Moloney murine leukemia virus integration site 1 (BMI1), part of polycomb repressive complex 1 (PRC1), is a key transcription factor overexpressed in OSCC. Although increased BMI1 has been linked to tumor formation in mouse models of the disease, the molecular mechanisms have not been elucidated. Here we used a transgenic mouse line (KrTB) that selectively overexpresses BMI1 in the tongue basal epithelial stem cells (SCs) to delineate BMI1 actions during oral tumorigenesis. By tumor pathological classification after 4-nitroquinoline 1-oxide (4-NQO)-induced carcinogenesis we detected more severe tumors in mice with ectopic BMI1 expression. Genome-wide transcriptomics indicated that mRNAs associated with human OSCC, including SOX9, HIF1A, MMP9, INHBB, and MYOF, were further increased by ectopic BMI1 expression in murine tongue epithelia. mRNAs encoding multiple metabolic targets, such as SLC2A1 (GLUT1), PKM, LDHA, and HK2, were also increased upon BMI1 overexpression in 4-NQO-treated tongue epithelia. Furthermore, we detected BMI1, SOX9, and GLUT1 proteins in the infiltrating cells of invasion fronts identified by markers of invasive SCCs. Finally, metabolomic data show that BMI1 overexpression in tongue epithelia promotes glycolysis during 4-NQO-induced carcinogenesis. Thus, our data demonstrate that BMI1 causes OSCC cells to alter cell metabolism, as changes in many of these transcripts are linked to increased glycolysis and metabolic reprograming that occurs during carcinogenesis.

Epithelial membrane protein 1 in human cancer: a potential diagnostic biomarker and therapeutic target

Epithelial membrane protein 1 (EMP1) is a member of the small hydrophobic membrane protein subfamily. EMP1 is aberrantly expressed in various tumor tissues and governs multiple cellular behaviors (e.g., proliferation, differentiation, and migration). The resultant regulation of the cancer pathway is responsible for the metastasis of cancer cells and determines the risk of malignant tumor progression. This review provides an updated overview of EMP1 as either an oncogene or a tumor suppressor contingent on the cancer type and summarizes its upstream regulators and downstream target genes. This systematic review summarizes our current understanding of the role of EMP1 in malignant tumor development, including critical functional mechanisms and implications for its potential use as the biomarker and therapeutic target.

Fusobacterium nucleatum induces invasive growth and angiogenic responses in malignant oral keratinocytes that are cell line- and bacterial strain-specific

Fusobacterium nucleatum is an anaerobic commensal of the oral cavity recently reported to be associated with cancers of the gastrointestinal tract and oral squamous cell carcinoma (OSCC). In this study, we investigate the impact on oral keratinocytes of infection with a genetically diverse set of strains of F. nucleatum subsp. polymorphum recovered from patients with oral dysplasia (n=6). We employed H357 oral keratinocytes derived from a stage 1 OSCC and H376 cells derived from a stage 3 OSCC. Adhesion phenotypes were strain specific, with 3/6 clinical isolates examined exhibiting higher adherence to the stage 3 H376 cell line. Conversely, intracellular invasion was greatest in the H357 cells and was associated with specific transcriptional responses including autophagy and keratinization. Infection of both H357 and H376 cell lines induced transcriptional and cytokine responses linked to cancer cell migration and angiogenesis. F. nucleatum infection induced greater levels of MMP9 secretion in the H376 cell line which was associated with enhanced motility and invasion phenotypes. Additionally, the degree of F. nucleatum induced invasive growth by H376 cells varied between different clinical isolates of F. nucleatum subsp. polymorphum. Blockage of CCL5 signalling using the inhibitor metCCL5 resulted in reduced keratinocyte invasion. F. nucleatum infection also induced expression of the pro-angiogenic chemokine MCP-1 and the angiogenic growth factor VEGF-A resulting in increased capillary-like tube formation in HUVEC cells, most significantly in H376 cells. Treatment of HUVEC cells with resveratrol, a VEGF-A signalling inhibitor, significantly attenuated F. nucleatum induced tube formation. Our data indicate that the outcomes of F. nucleatum-oral cell interactions can vary greatly depending on the bacterial genotype and the malignant phenotype of the host cell.

In vitro antimetastatic potential of pseudolaric acid B in HSC-3 human tongue squamous carcinoma cell line

OBJECTIVE

Pseudolaric acid B (PAB) is a novel diterpenoid derived from the traditional Chinese medicinal herb Cortex pseudolaricis that exerts anticancer, anti-inflammatory, and immunomodulatory properties. While the anticancer potential of PAB has been studied, its effects on metastasis have not been well-studied. This study aims to determine the inhibitory effects of PAB on HSC-3 human tongue squamous cell carcinoma (TSCC) cell line.

DESIGN

Cell viability and soft agar colony formation assays were conducted to assess cellular proliferation and in vitro tumorigenic capacity of TSCC cells, respectively. Additionally, wound healing, transwell migration, and invasion assays were conducted to monitor the aggressive behavior of TSCC cells. Furthermore, Western blotting analysis was conducted to reveal the signaling pathways involved in the modulation of epithelial-mesenchymal transition (EMT).

RESULTS

The migratory and invasive capacities of HSC-3 cells were suppressed by PAB irrespective of their proliferation states. PAB's effects on EMT involved upregulation of E-cadherin expression and downregulation of Twist; these were concomitantly accompanied by downregulated phosphorylation of epidermal growth factor receptor (EGFR).

CONCLUSIONS

PAB suppresses human TSCC in vitro by regulating Twist/E-cadherin through the EGFR signaling pathway. PAB may have potential as a candidate antimetastatic drug for TSCC treatment.

EMP3: A promising biomarker for tumor prognosis and targeted cancer therapy

Epithelial membrane protein 3 (EMP3) belongs to the peripheral myelin protein 22 kDa (PMP22) gene family, characterized by four transmembrane domains and widespread expression across various human tissues and organs. Other members of the PMP22 family, including EMP1, EMP2, and PMP22, have been linked to various cancers, such as glioblastoma, laryngeal cancer, nasopharyngeal cancer, gastric cancer, breast cancer, and endometrial cancer. However, few studies report on the function and relevance of EMP3 in tumorigenicity. Given the significant structural similarities among members of the PMP22 family, there are likely potential functional similarities as well. Previous studies have established the regulatory role of EMP3 in immune cells like T cells and macrophages. Additionally, EMP3 is found to be involved in critical signaling pathways, including HER-2/PI3K/Akt, MAPK/ERK, and TGF-beta/Smad. Furthermore, EMP3 is associated with cell cycle regulation, cellular proliferation, and apoptosis. Hence, it is likely that EMP3 participates in cancer development through these aforementioned pathways and mechanisms. This review aims to systematically examine and summarize the structure and function of EMP3 and its association to various cancers. EMP3 is expected to emerge as a significant biological marker for tumor prognosis and a potential target in cancer therapeutics.

Specific Oral Microbial Differences in Proteobacteria and Bacteroidetes Are Associated with Distinct Sites When Moving from Healthy Mucosa to Oral Dysplasia-A Microbiome and Gene Profiling Study and Focused Review

Oral potentially malignant disorders (OPMDs) are a group of conditions that carry a risk of oral squamous cell carcinoma (OSCC) development. Recent studies indicate that periodontal disease-associated pathogenic bacteria may play a role in the transition from healthy mucosa to dysplasia and to OSCC. Yet, the microbial signatures associated with the transition from healthy mucosa to dysplasia have not been established. To characterize oral microbial signatures at these different sites, we performed a 16S sequencing analysis of both oral swab and formalin-fixed, paraffin-embedded tissue (FFPE) samples. We collected oral swabs from healthy mucosa (from healthy patients), histologically normal mucosa adjacent to dysplasia, and low-grade oral dysplasia. Additionally, FFPE samples from histologically normal mucosa adjacent to OSCC, plus low grade and high-grade oral dysplasia samples were also collected. The collected data demonstrate significant differences in the alpha and beta microbial diversities of different sites in oral mucosa, dysplasia, and OSCC, as well as increased dissimilarities within these sites. We found that the Proteobacteria phyla abundance increased, concurrent with a progressive decrease in the Firmicutes phyla abundance, as well as altered levels of Enterococcus cecorum, Fusobacterium periodonticum, Prevotella melaninogenica, and Fusobacterium canifelinum when moving from healthy to diseased sites. Moreover, the swab sample analysis indicates that the oral microbiome may be altered in areas that are histologically normal, including in mucosa adjacent to dysplasia. Furthermore, trends in specific microbiome changes in oral swab samples preceded those in the tissues, signifying early detection opportunities for clinical diagnosis. In addition, we evaluated the gene expression profile of OSCC cells (HSC-3) infected with either P. gingivalis, T. denticola, F. nucelatum, or S. sanguinis and found that the three periodontopathogens enrich genetic processes related to cancer progression, including skin keratinization/cornification, while the commensal enriched processes related to RNA processing and adhesion. Finally, we reviewed the dysplasia microbiome literature and found a significant decrease in commensal bacteria, such as the Streptococci genus, and a simultaneous increase in pathogenic bacteria, mainly Bacteroidetes phyla and Fusobacterium genus. These findings suggest that features of the oral microbiome can serve as novel biomarkers for dysplasia and OSCC disease progression.

TWIST1 regulates proliferation, migration, and invasion and is a prognostic marker for oral tongue squamous cell carcinoma

BACKGROUND

Epithelial-mesenchymal transition is one of the main mechanisms for tumor progression and metastasis. Transcription factors such as TWIST1 are key regulators of the epithelial-mesenchymal transition and are regarded as potential therapeutic targets for the treatment of cancer. The purpose of this study was to examine TWIST1 as a possible epithelial-mesenchymal transition-related prognostic biomarker in oral epithelial dysplasia and oral tongue squamous cell carcinomas, as well as the biological behavior of TWIST1-silencing in oral tongue squamous cell carcinomas cell lines.

METHODS

Immunohistochemical analysis of TWIST1, E-cadherin, and N-cadherin was carried out in 47 samples representing oral epithelial dysplasia and 41 oral tongue squamous cell carcinomas. The suppression of TWIST1 expression was performed using shRNA-expression vectors in HSC-3 and SCC-9 cells to investigate in vitro the impact of TWIST1 on proliferation, apoptosis, viability, migration, and invasion of SCC-9 and HSC-3 cells.

RESULTS

The expression of nuclear TWIST1 was significantly higher in oral tongue squamous cell carcinomas than in oral epithelial dysplasis (p < 0.0001), whereas TWIST1 in the cytoplasm was more expressed in oral epithelial dysplasis (p = 0.012). The high cytoplasmic expression of TWIST1 was significantly associated with shortened overall survival (p < 0.05), and increased nuclear TWIST1 expression was significantly related to high risk of recurrence (p = 0.03). Knockdown of TWIST1 in oral tongue squamous cell carcinomas cells induced the expression of E-cadherin and inhibited N-cadherin, which were followed by decreased proliferation, migration, and invasion.

CONCLUSIONS

Our research suggests that TWIST1 is linked to the development of oral tongue carcinogenesis and may be used as a prognostic indicator and therapeutic target for oral tongue squamous cell carcinomas patients.

Influence of site and smoking on malignant transformation in the oral cavity: Is the microbiome the missing link?

The tongue and floor of the mouth are high-risk sites for oral squamous cell carcinoma (OSCC), while smoking is its most significant risk factor. Recently, questions have been raised as to the role of the oral microbiome in OSCC because of a wealth of evidence demonstrating that the microbiome of OSCC differs from that of healthy mucosa. However, oral site and smoking also have a significant impact on oral microbial communities, and to date, the role these factors play in influencing the dysbiotic microbial communities of OSCC and precursor lesions has not been considered. This review aims to examine the influence of site and smoking on the oral microbiome and, in turn, whether these microbiome changes could be involved in oral carcinogenesis.

EZH2 Knockout in Oral Cavity Basal Epithelia Causes More Invasive Squamous Cell Carcinomas

Oral squamous cell carcinoma (oral SCC) is an aggressive disease and despite intensive treatments, 5-year survival rates for patients have remained low in the last 20 years. Enhancer of zeste homolog 2 (EZH2), part of polycomb repressive complex 2 (PRC2), is highly expressed in human oral SCC samples and cell lines and has been associated with greater epithelia-to-mesenchymal transition (EMT), invasion, and metastasis. Here we developed a tamoxifen-regulated, transgenic mouse line (KcEZH2) in which EZH2 is selectively knocked out (KO) in some tongue epithelial basal stem cells (SCs) in adult mice. EZH2 KO SCs do not show the H3K27me3 mark, as assessed by double-label immunofluorescence. We used this mouse line to assess EZH2 actions during oral tumorigenesis with our immunocompetent 4-nitroquinoline 1-oxide (4-NQO) model of oral SCC. We report that higher percentages of mice with invasive SCCs and high-grade neoplastic lesions are observed in mice containing EZH2 KO SCs (KcEZH2-2TΔ and KcEZH2-5TΔ mice). Moreover, EZH2 expression does not correlate with the expression of markers of invasive SCCs. Finally, EZH2 KO cells that are E-cadherin+ are present at invasion fronts infiltrating underlying muscle tissue. Our findings indicate that the knockout of EZH2 in basal SCs of tongue epithelia results in more aggressive carcinomas, and this should be considered when targeting EZH2 as a therapeutic strategy.

Microbiome and oral squamous cell carcinoma: a possible interplay on iron metabolism and its impact on tumor microenvironment

There is increasing evidence showing positive association between changes in oral microbiome and the occurrence of oral squamous cell carcinoma (OSCC). Alcohol- and nicotine-related products can induce microbial changes but are still unknown if these changes are related to cancerous lesion sites. In an attempt to understand how these changes can influence the OSCC development and maintenance, the aim of this study was to investigate the oral microbiome linked with OSCC as well as to identify functional signatures and associate them with healthy or precancerous and cancerous sites. Our group used data of oral microbiomes available in public repositories. The analysis included data of oral microbiomes from electronic cigarette users, alcohol consumers, and precancerous and OSCC samples. An R-based pipeline was used for taxonomic and functional prediction analysis. The Streptococcus spp. genus was the main class identified in the healthy group. Haemophilus spp. predominated in precancerous lesions. OSCC samples revealed a higher relative abundance compared with the other groups, represented by an increased proportion of Fusobacterium spp., Prevotella spp., Haemophilus spp., and Campylobacter spp. Venn diagram analysis showed 52 genera exclusive of OSCC samples. Both precancerous and OSCC samples seemed to present a specific associated functional pattern. They were menaquinone-dependent protoporphyrinogen oxidase pattern enhanced in the former and both 3',5'-cyclic-nucleotide phosphodiesterase (purine metabolism) and iron(III) transport system ATP-binding protein enhanced in the latter. We conclude that although precancerous and OSCC samples present some differences on microbial profile, both microbiomes act as "iron chelators-like" potentially contributing to tumor growth.

Oral Potentially Malignant Disorders (OPMD): What is the clinical utility of dysplasia grade?

INTRODUCTION

Oral epithelial dysplasia is considered a potential histologic precursor of subsequent squamous cell cancer. As standard clinical practice, pathologists grade dysplasia to assess risk for progression to malignancy. Except for the most advanced grade, severe dysplasia, dysplasia grading has failed to correlate well with the risk to develop invasive cancer. The questions of what process dysplasia grading best represents and what clinical utility dysplasia grading may have are explored.

AREAS COVERED

This narrative review is based on PubMed search with emphasis on papers since 2010. Epithelial dysplasia as a precursor lesion of cancer and dysplasia grading as a risk assessment tool for progression to cancer are discussed. The close clinical association of dysplasia with known carcinogens, alcohol, and tobacco products is presented.

EXPERT OPINION

Oral epithelial dysplasia is often, associated with prolonged exposure to tobacco and alcohol products. With reduction of carcinogen exposure, dysplasia is known to regress in some cases. It is proposed that histologic dysplasia grade together with macroscopic images of dysplastic clinical lesions be used as an educational tool to incentivize patients to reduce their known carcinogen exposure. This strategy has the potential to reduce lesion progression thereby reducing the disease burden of oral cancer.

Markers of Angiogenesis, Lymphangiogenesis, and Epithelial-Mesenchymal Transition (Plasticity) in CIN and Early Invasive Carcinoma of the Cervix: Exploring Putative Molecular Mechanisms Involved in Early Tumor Invasion

The establishment of a proangiogenic phenotype and epithelial-to-mesenchymal transition (EMT) are considered as critical events that promote the induction of invasive growth in epithelial tumors, and stimulation of lymphangiogenesis is believed to confer the capacity for early dissemination to cancer cells. Recent research has revealed substantial interdependence between these processes at the molecular level as they rely on common signaling networks. Of great interest are the molecular mechanisms of (lymph-)angiogenesis and EMT associated with the earliest stages of transition from intraepithelial development to invasive growth, as they could provide the source of potentially valuable tools for targeting tumor metastasis. However, in the case of early-stage cervical cancer, the players of (lymph-)angiogenesis and EMT processes still remain substantially uncharacterized. In this study, we used RNA sequencing to compare transcriptomes of HPV(+) preinvasive neoplastic lesions and early-stage invasive carcinoma of the cervix and to identify (lymph-)angiogenesis- and EMT-related genes and pathways that may underlie early acquisition of invasive phenotype and metastatic properties by cervical cancer cells. Second, we applied flow cytometric analysis to evaluate the expression of three key lymphangiogenesis/EMT markers (VEGFR3, MET, and SLUG) in epithelial cells derived from enzymatically treated tissue specimens. Overall, among 201 differentially expressed genes, a considerable number of (lymph-)angiogenesis and EMT regulatory factors were identified, including genes encoding cytokines, growth factor receptors, transcription factors, and adhesion molecules. Pathway analysis confirmed enrichment for angiogenesis, epithelial differentiation, and cell guidance pathways at transition from intraepithelial neoplasia to invasive carcinoma and suggested immune-regulatory/inflammatory pathways to be implicated in initiation of invasive growth of cervical cancer. Flow cytometry showed cell phenotype-specific expression pattern for VEGFR3, MET, and SLUG and revealed correlation with the amount of tumor-infiltrating lymphocytes at the early stages of cervical cancer progression. Taken together, these results extend our understanding of driving forces of angiogenesis and metastasis in HPV-associated cervical cancer and may be useful for developing new treatments.

Spinal N-Cadherin/CREB Signaling Contributes to Chronic Alcohol Consumption-Enhanced Postsurgical Pain

BACKGROUND

It has been reported that N-cadherin and cAMP response element binding protein (CREB) in the spinal cord are critical for synaptogenesis and regulation of excitatory synapse function, which could underlie chronic pain development. The aim of the present study was to investigate the role of spinal N-cadherin/CREB signaling in postsurgical pain chronicity following chronic alcohol consumption.

METHODS

C57BL/6 male mice were randomly assigned into different groups. Plantar incision was used to induce postsurgical pain. Chronic alcohol consumption was conducted by giving mice unlimited access to different concentrations of ethanol for five weeks. We measured paw withdrawal thresholds to test postsurgical pain. Using Western blotting, we examined the expression of N-Cadherin and CREB in the spinal dorsal horn. We further performed intrathecal injection of specific N-cadherin and CREB inhibitors to assess the role of spinal N-cadherin/CREB signaling in chronic alcohol consumption-enhanced postsurgical pain.

RESULTS

We observed that the chronic alcohol consumption significantly prolonged postsurgical pain and enhanced plantar incision-increased N-cadherin expression and CREB phosphorylation at the Ser133 in the spinal cord. Intrathecal injection of specific N-cadherin and CREB inhibitors attenuated chronic alcohol consumption-prolonged postsurgical pain.

CONCLUSION

Our results suggest that spinal N-cadherin/CREB signaling is involved in chronic alcohol consumption-caused postsurgical pain chronicity.

Identification of SPRR3 as a novel diagnostic/prognostic biomarker for oral squamous cell carcinoma via RNA sequencing and bioinformatic analyses

Oral squamous cell carcinoma (OSCC) has always been one of the most aggressive and invasive cancers among oral and maxillofacial malignancies. As the morbidity and mortality of the disease have increased year by year, the search for a promising diagnostic and prognostic biomarker for the disease is becoming increasingly urgent. Tumorous and adjacent tissues were collected from three OSCC sufferers and we obtained 229 differentially expressed genes (DEGs) between tumor and normal tissues via high-throughput RNA sequence. Function and pathway enrichment analyses for DEGs were conducted to find a correlation between tumorigenesis status and DEGs. Protein interaction network and molecular complex detection (MCODE) were constructed to detect core modules. Two modules were enriched in MCODE. The diagnostic and prognostic values of the candidate genes were analyzed, which provided evidence for the candidate genes as new tumor markers. Small Proline Rich Protein 3 (SPRR3), a potential tumor marker that may be useful for the diagnosis of OSCC, was screened out. The survival analysis showed that SPRR3 under expression predicted the poor prognosis of OSCC patients. Further experiments have also shown that the expression of SPRR3 decreased as the malignancy of OSCC increased. Therefore, we believe that SPRR3 could be used as a novel diagnostic and prognostic tumor marker.

[Study on expression of LIM domain only protein 1 in SD rat oral buccal mucosa carcinogenesis induced by 4-nitro-quinoline N-oxide]

OBJECTIVE

This work aimed to determine the expression changes in LIM domain only protein 1 (LMO1) in gene transcription and protein levels during oral squamous cell carcinoma (OSCC) development.

METHODS

The tissues in this study were taken from our team's previous animal model building, and we performed hematoxylin-eosin (HE) staining on 49 cases. The pathological classification of the experiment group was determined on the basis of the abnormal epithelial hyperplasia degree. The expression part of LMO1 was determined by immunohistochemistry staining. The mRNA and protein LMO1 expression levels in five groups were detected by real-time fluorescent quantitative of nucleotide polymer chain reaction (RT-qPCR) and Western blot, respectively.

RESULTS

HE staining determined 7 cases of the control group, 6 cases of mild epithelial dysplasia, 11 cases of moderate epithelial dysplasia, 9 cases of severe epithelial dysplasia, and 16 cases of OSCC. Immunohistochemistry results: LMO1 expression was localized in the cytoplasm, and the positive expression rates of the protein LMO1 in the control and experiment groups were 14.3% for normal buccal mucosal tissue, 33.3% for mild epithelial dysplasia, 81.8% for moderate epithelial dysplasia, 88.9% for severe epithelial dysplasia, and 93.8% for OSCC. RT-qPCR results: mRNA expression was lowest in the control group and highest in the OSCC group, the difference between the mild dysplasia and control groups was not significant (P>0.05). Pairwise comparison among other groups showed statistically significant differences (P<0.05). Western blot results: with the aggravation of the pathological degree, the protein LMO1 expression level increased gradually. The OSCC group expressed the highest LMO1 expression level.

CONCLUSIONS

The oral mucosa carcinogenesis models showed abnormal the mRNA and protein LMO1 expression levels, and the mRNA and protein expression levels were positively correlated with the degree of abnormal proliferation.

Prognostic value of the immunohistochemical detection of epithelial-mesenchymal transition biomarkers in oral epithelial dysplasia: A systematic review

BACKGROUND

Oral potentially malignant disorders (OPMDs) comprise a range of clinical-pathological alterations that are frequently characterized as architectural and cytological derangements upon histological analysis. Epithelial-mesenchymal transition (EMT) has been proposed as a critical mechanism for the acquisition of the malignant phenotype in neoplastic epithelial processes. This study aims to systematically review the current findings on the immunohistochemical expression of epithelial-mesenchymal transition markers in oral potentially malignant disorders and to evaluate their possible application as biomarkers associated with the progression of oral epithelial dysplasias.

MATERIAL AND METHODS

A systematic search was performed in the following databases: PubMed, EMBASE, Chinese BioMedical Literature Database, and Cochrane Library. Articles that evaluated the relationship between the expression of EMT markers and the degree of oral epithelial dysplasia were selected for the systematic review. The quality of each eligible study was evaluated by independent reviewers that used operationalized prognostic biomarker reporting guidelines (REMARK).

RESULTS

Seventeen articles met all inclusion criteria and were selected. The EMT markers analyzed exhibited an important association with the prognosis of the cases evaluated. The results showed a progressive increase in the expression of nuclear transcription factors and markers of mesenchymal differentiation, as well as negative regulation of epithelial and cell adhesion markers, according to the stage of oral epithelial dysplasia.

CONCLUSIONS

The dysregulation of expression of important EMT components in oral dysplastic epithelium is a potential prognostic marker in OPMDs.