Epithelial-mesenchymal transition in oral squamous cell carcinoma: An insight into molecular mechanisms and clinical implications

Integrated analysis of non‑coding RNAs (HOTAIR and miR‑130a) and their cross‑talk with TGF‑β1, SIRT1 and E‑cadherin as potential biomarkers in colorectal cancer

Molecular changes have a substantial impact on the onset of colorectal cancer (CRC). Complexes of HOTAIR and miRNAs disrupt several cellular functions during carcinogenesis, primarily by disrupting several carcinogenic signaling pathways. In the present study, the relationships between the serum levels of transforming growth factor-β1 (TGF-β1), sirtuin-1 (SIRT1) and E-cadherin and those of HOX transcript antisense intergenic RNA (HOTAIR) and microRNA-130a (miR-130a) in individuals with CRC were analyzed, including their correlations and diagnostic potential. Patients with colon cancer and healthy volunteers were enrolled in the study. Blood samples were collected from 70 patients with CRC and 30 age-matched healthy control volunteers and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to determine the serum levels of HOTAIR and miR-130a. In addition, the levels of TGF-β1, SIRT1 and E-cadherin were determined utilizing enzyme-linked immunosorbent assays. Patients with CRC were found to have significantly higher TGF-β1, SIRT1, HOTAIR and miR-130a serum levels than those of healthy participants. In addition, patients with high-grade CRC had significantly higher levels of TGF-β1, SIRT1, HOTAIR and miR-130a compared with those of patients with low-grade CRC. A significant reduction in the serum levels of E-cadherin was observed in participants with CRC compared with healthy participants, but no significant difference was detected according to the grade of CRC. Positive correlations were found between HOTAIR and miR-130a, as well as TGF-β1 and SIRT1. By contrast, negative correlations were noted between E-cadherin and HOTAIR, miR-130a, TGF-β1 and SIRT1. Therefore, it may be concluded that the miR-130a/HOTAIR and TGF-β1/SIRT1/E-cadherin axes may serve as novel biomarkers for the early diagnosis of CRC.

Antiproliferative Effects of Methanolic Fruit Extract of Solanum xenthocarpum (L.) on Human Breast Cancer Cells

Solanum xanthocarpum, a perennial herb native to India, contains steroidal glycoalkaloids with notable anticancer properties. This study investigated the antioxidant and antiproliferative effects of methanolic fruit extract of S. xanthocarpum on human breast cancer cells (MDA-MB-231). Phytochemical screening and LC-HRMS analysis confirmed presence of various primary and secondary metabolites. Antioxidant activity was assessed through DPPH, ABTS radical scavenging, reducing power, and phosphomolybdate assays. The extract demonstrated significant antioxidant potential with EC50 values of 60.10±0.88 μg/mL (DPPH) and 392.29±3.93 μg/mL (ABTS). Cytotoxicity against MDA-MB-231 cells was evaluated via morphological analysis, MTT assays, and IC50 determination (24.19±0.56 μg/L). Apoptosis was confirmed using dual staining techniques (AO/EB, Hoechst 33342/PI, DAPI), revealing condensed nuclei, apoptotic bodies, and reduced mitochondrial membrane potential, as indicated by Rhodamine staining. Additionally, increased reactive oxygen species (ROS) levels were observed using H2-DCF-DA staining. The total phenolic and flavonoid contents of the extract were 127.78±3.547 mg GAE/g and 98.06±4.289 mg QE/g, respectively. These findings suggest that the methanolic fruit extract of S. xanthocarpum possesses strong antioxidant and anticancer activities, indicating its potential role in cancer treatment. Further studies are warranted to explore its bioactive compounds for developing novel anticancer therapies.

FNDC5 affects invasion and migration of oral cancer by inhibiting PI3K/Akt/Snail signaling pathway

This study first investigated how FNDC5 affected the development of oral cancer and revealed the role of FNDC5 in the migration and invasion of oral cancer. The present work evaluated differential FNDC5 expression within oral cancer samples versus matched non-carcinoma samples based on GEO database analysis and immunohistochemistry. We then generated oral cancer cell lines with FNDC5 overexpression and knockdown to determine the role of altered FNDC5 expression in the migration and invasion of oral cancer. PI3K inhibitor was used for investigating the possible mechanism underlying FNDC5 during EMT of oral cancer. Finally, these in-vitro results were validated using the lung metastatic nude mouse model. According to our results, FNDC5 level markedly decreased within oral cancer compared with adjacent samples and FNDC5 overexpression inhibited migration, invasion as well as EMT of oral cancer, while FNDC5 knockdown promoted oral cancer cell EMT. In addition, PI3K inhibitors blocked the induction of oral cancer cells EMT by FNDC5 knockdown. In vivo experiments further demonstrated the above results. This work is the first to illustrate the impact of FNDC5 on inhibiting migration and invasion of oral cancer, and our results suggest that FNDC5 affects EMT of oral cancer via the inhibition of PI3K/Akt/Snail pathway.

Isolation and phenotypic characterization of cancer stem cells from metastatic oral cancer cells

OBJECTIVES

To isolate cancer stem cells (CSC) from a metastatic oral squamous cell carcinoma (OSCC) cell line and investigate their in vitro and in vivo phenotypic characteristics.

MATERIALS AND METHODS

Subpopulations with individual staining intensities for CD44 and CD326 were isolated from the OSCC cell line LN-1A by FACS: CD44Low/CD326- (CSC-M1), CD44Low/CD326High (CSC-E), and CD44High/CD326- (CSC-M2). Proliferation, clonogenic potential, adhesion, migration, epithelial-mesenchymal transition markers, and sensitivity to cisplatin and TVB-3166 were analyzed in vitro. Tumor formation and metastasis were assessed by subcutaneous and orthotopic inoculations into BALB/c mice.

RESULTS

E-cadherin levels were higher in CSC-E cells while vimentin and Slug more produced by CSC-M2 cells. CSC-M1 and CSC-M2 subpopulations showed higher proliferation, produced more colonies, and have stronger adhesion to the extracellular matrix. All cell lines established tumors; however, CSC-E and CSC-M2 formed larger masses and produced more metastases.

CONCLUSION

The CSC subpopulations here described show increased cancer capabilities in vitro, tumorigenic and metastatic potential in vivo, and may be exploited in the search for novel therapeutic targets for OSCC.

The roles of lncRNAs in the development of drug resistance of oral cancers

Oral cancers are a significant global health concern, with a high incidence of treatment failure primarily due to the development of drug resistance. Long non-coding RNAs (lncRNAs) have emerged as critical regulators of gene expression, playing pivotal roles in various cellular processes, including tumor progression and response to therapy. This review explores the multifaceted roles of lncRNAs in the development of drug resistance in oral cancers. We highlight the mechanisms by which lncRNAs modulate drug efflux, apoptosis, epithelial-mesenchymal transition (EMT), and other pathways associated with chemoresistance. Key lncRNAs implicated in resistance to commonly used chemotherapeutic agents in oral cancers are discussed, along with their potential as therapeutic targets. Understanding the involvement of lncRNAs in drug resistance mechanisms offers promising avenues for overcoming treatment barriers and improving patient outcomes. This review underscores the need for further research to elucidate the precise roles of lncRNAs in oral cancer resistance and their translation into clinical interventions.

PRELP inhibits the progression of oral squamous cell carcinoma via inactivation of the NF-κB pathway

OBJECTIVES

The aim of this study was to investigate the role and molecular mechanism of proline/arginine-rich end leucine-rich repeat protein (PRELP), a secreted protein in extracellular matrix, in oral squamous cell carcinoma (OSCC) progression.

DESIGN

PRELP expression in OSCC was analyzed in the Gene Set Enrichment (GSE) 138206, GSE37991, and GSE23558 datasets as well as cell lines. Also, PRELP expression and its relationship with prognosis and immune infiltration in head and neck squamous cell carcinoma (HNSCC) were confirmed by bioinformatics analysis. The proliferation, apoptosis, invasion, epithelial-to-mesenchymal transition (EMT) and NF-κB activation were detected after alteration of PRELP expression in OSCC cells using CCK-8, EdU, flow cytometry, Transwell, real-time PCR, immunofluorescence and Western blot. Additionally, an NF-κB inhibitor PDTC was used to confirm the regulation mechanism of PRELP.

RESULTS

The expression of PRELP in OSCC tissues, cells and in HNSCC samples was low. HNSCC patients with higher PRELP expression was associated with longer overall survival. A positive correlation between PRELP expression and immune cell infiltration was found in HNSCC. Upregulation of PRELP inhibited, whereas PRELP silencing promoted, the proliferation, invasion and EMT of OSCC cells. Also, overexpression of PRELP promoted cell apoptosis. Mechanistically, PRELP suppressed p65 phosphorylation and nuclear translocation. And PDTC treatment partially reversed the influences of PRELP knockdown on the malignant behaviors in OSCC cells.

CONCLUSION

PRELP suppressed OSCC progression via inactivation of the NF-κB pathway. Targeting PRELP may be a potential approach for OSCC treatment.

Conotoxins: emerging analgesics for neck and spinal surgery pain management

Conotoxins, peptides derived from the venom of marine cone snails, have emerged as promising analgesics for managing pain associated with neck and spinal surgery. These toxins target specific neurotransmitter receptors and ion channels in the nervous system, offering an alternative to traditional opioids with potentially fewer side effects. By interacting with receptors such as nicotinic acetylcholine and voltage-gated sodium and calcium channels, conotoxins disrupt pain signal transmission and induce muscle relaxation, providing effective pain relief. Research into conotoxins is ongoing, with the goal of developing novel, safer analgesics that mitigate the risks of opioid addiction. This exploration not only holds promise for surgical pain management but also advances our understanding of venom pharmacology and its therapeutic applications.

Vitamin D-metabolizing enzyme CYP24A1 affects oncogenic behaviors of oral squamous cell carcinoma and its prognostic implication

Vitamin D is an essential molecule for cellular homeostasis, playing a critical role in cell fate decisions including cell proliferation, differentiation, and viability. Accumulating evidence has revealed that expression of the vitamin D-metabolizing enzyme CYP24A1 is dysregulated in different types of human malignancy. CYP24A1 has been shown to be involved in the oncogenic property of a variety of carcinoma cells. However, the pathological relevance of CYP24A1 expression level in human oral malignancy remains to be clarified. In the present study, suppression of CYP24A1 expression in oral squamous cell carcinoma (OSCC) cells increased cell proliferation, invasive activity, colony formation efficacy, and tumor growth in vivo. In addition, knockout of CYP24A1 expression inhibited cell death induced by two different types of anticancer drugs, i.e., fluorouracil and cisplatin. Gene clustering by RNA-sequence analysis revealed that several signaling molecules associated with MYC are involved in CYP24A1-mediated oncogenic behaviors. Furthermore, decreased expression level of CYP24A1 was observed in 124/204 cases (61%) of OSCC and was shown to be associated with short relapse-free and overall survival periods. The results showed that a low expression level of CYP24A1 promotes the oncogenic activity of OSCC and is significantly associated with poor prognosis in patients with this malignancy.

Waterpipe smoke condensate induces epithelial-mesenchymal transformation and promotes metastasis of oral cancer by FOXD1 expression

BACKGROUND/PURPOSE

Smoking is a major contributor to global oral cancer cases, necessitating urgent intervention. FOXD1, involved in developmental processes and various cancers, shows promise as a prognostic marker in oral squamous cell carcinoma (OSCC). This study investigates the impact of waterpipe smoke condensate (WPSC) on OSCC, focusing on FOXD1 role in inducing epithelial-mesenchymal transition (EMT) and metastasis.

METHODS

The study involved using OSCC cells treated with WPSC to evaluate their proliferation, colony formation, gene expression, and protein levels. The researchers also explored the clinical relevance of their findings using online databases to analyze FOXD1 expression in cancer tissues and its correlation with clinicopathological features and patient survival. Additionally, in silico tools were employed for functional analysis, pathway enrichment, and network exploration.

RESULTS

The study found that WPSC increased the expression of FOXD1 in OSCC cells, which led to increased cell growth. The study also showed that FOXD1 plays a critical role in the EMT process induced by WPSC, as evidenced by changes in the expression of EMT-related genes and proteins. Clinical analysis revealed that FOXD1 was significantly associated with more aggressive tumor features and poorer prognosis in cancer patients.

CONCLUSION

The study highlights FOXD1 as a key player in OSCC pathogenesis and a potential prognostic marker and therapeutic target, particularly when influenced by WPSC exposure. Further research is needed to explore FOXD1 molecular mechanisms and clinical implications to enhance OSCC treatment strategies.

A Comparative immunohistochemical analysis of epithelial-mesenchymal transition biomarkers in odontogenic keratocyst, dentigerous cyst, and radicular cyst

Background

Odontogenic keratocyst (OKC) is one of the common odontogenic cysts with aggressive clinical behavior and a high recurrence rate. Epithelial-mesenchymal transition (EMT) is a process, in which the epithelial cell loses its epithelial characteristics and acquires mesenchymal features. Since the evidence for the involvement of EMT in the development of OKC is still limited, the present study aimed to investigate the immunohistochemical expression of EMT-related proteins (E-cadherin and N-cadherin) in OKC and compare them to radicular cyst (RC) and dentigerous cyst (DC).

Materials and Methods

In this descriptive analytical study, 75 paraffin blocks, including 25 DCs, 25 OKC, and 25 RCs, were selected. Immunohistochemical staining was performed to determine the expression and staining intensity of E-cadherin and N-cadherin proteins. The specimens were examined under an optical microscope, and the data were analyzed using the Kruskal-Wallis test in SPSS statistical software (version 23) with a significance level of 5%.

Results

The expression of N-cadherin in OKC was higher than that in other cysts; nonetheless, there was no statistically significant difference (P = 0.331). The staining intensity of N-cadherin was weak in most cases, and this difference was not statistically significant (P = 0.252). E-cadherin expression in OKC was significantly lower than that in radicular and DCs (P = 0.003). In addition, the staining intensity of E-cadherin in OKC was weak and moderate (P = 0.003).

Conclusion

In this study, we observed an increase in the expression of N-cadherin in OKC. In addition, the protein expression levels of E-cadherin in OKC were significantly lower compared to DC and RC. Therefore, it appears that the EMT process likely occurs in OKC and may contribute to its local aggressive behavior.

FAM122A functions as a tumor suppressor in oral squamous cell carcinoma

Family with sequence similarity 122a (FAM122A), identified as an endogenous inhibitor of protein phosphatase 2A (PP2A) previously, is involved in multiple important physiological processes, and essential for the growth of acute myeloid leukemia and hepatocellular carcinoma cells. However, the function of FAM122A in oral squamous cell carcinoma (OSCC) is undetermined. In this study, by analyzing TCGA and GEO databases, we found that the expression of FAM122A was significantly down-regulated in head and neck squamous cell carcinoma and OSCC patients, meanwhile this low expression was tightly associated with the poor prognosis and advanced clinical stage during OSCC development. The similar low expression pattern of FAM122A could also been seen in OSCC cell lines compared with normal human oral keratinocytes. Further, we demonstrated that FAM122A knockdown significantly promoted the growth, clonogenic potential as well as migration capabilities of OSCC cells, while these alterations could be rescued by the re-expression of FAM122A. Over-expression of FAM122A suppressed OSCC cell proliferation and migration. FAM122A also inhibited the epithelial-mesenchymal transition (EMT) in OSCC cells by the up-regulation of epithelial marker E-cadherin and down-regulation of mesenchymal markers Fibronectin and Vimentin, which is presumably mediated by transforming growth factor β receptor 3 (TGFBR3), a novel tumor suppressor. In addition, FAM122A could induce T cell infiltration in OSCC, indicating that FAM122A might influence the immune cell activity of tumor environment and further interfere the tumor development. Collectively, our results suggest that FAM122A functions as a tumor suppressor in OSCC and possibly acts as a predictive biomarker for the diagnosis and/or treatment of OSCC.

NK cell based immunotherapy against oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC), a major subtype of head and neck cancers, presents significant challenges due to its aggressive feature and limited therapeutic efficacy of conventional treatments. In response to these challenges, Natural Killer (NK) cells, a vital component of the innate immune system, are being explored for their therapeutic potential in OSCC due to their inherent ability to target and eliminate cancer cells without prior sensitization. This review uniquely focuses on the evolving role of NK cells specifically in OSCC, incorporating recent advancements in CAR-NK cell engineering and personalized therapy approaches that have not been comprehensively covered in previous reviews. The mechanisms through which NK cells exert cytotoxic effects on tumor cells include direct killing through the engagement of natural cytotoxic receptors and antibody-dependent cellular cytotoxicity (ADCC), making them promising agents in cancer immunotherapy. Additionally, the article explores recent advancements in engineering NK cells to enhance their antitumor activity, such as the modification with chimeric antigen receptors (CARs) to target specific tumor antigens. Clinical implications of NK cell-based therapies, including the challenges of integrating these treatments with existing protocols and the potential for personalized therapy, are examined. The review highlights the promise of NK cell therapies in improving outcomes for OSCC patients and outlines future directions for research in this dynamic field of oncological immunotherapy.

Matrix-based molecular mechanisms, targeting and diagnostics in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a head and neck cancer (HNC) with a high mortality rate. OSCC is developed in the oral cavity and it is triggered by many etiologic factors and can metastasize both regionally and distantly. Recent research advances in OSCC improved our understanding on the molecular mechanisms involved in and the initiation of OSCC metastasis. The key roles of the extracellular matrix (ECM) in OSCC are an emerging area of intensive research as the ECM macromolecular network is actively involved in events that regulate cellular morphological and functional properties, transcription and cell signaling mechanisms in invasion and metastasis. The provisional matrix that is formed by cancer cells is profoundly different in composition and functions as compared with the matrix of normal tissue. Fibroblasts are mainly responsible for matrix production and remodeling, but in cancer, the tumor matrix in the tumor microenvironment (TME) also originates from cancer cells. Even though extensive research has been conducted on the role of ECM in regulating cancer pathogenesis, its role in modulating OSCC is less elucidated since there are several issues yet to be fully understood. This critical review is focused on recent research as to present and discuss on the involvement of ECM macromolecular effectors (i.e., proteoglycans, integrins, matrix metalloproteinases) in OSCC development and progression.

NANOS1 restricts oral cancer cell motility and TGF-ß signaling

Oral squamous cell carcinoma (OSCC) is the most frequent type of cancer of the head and neck area accounting for approx. 377,000 new cancer cases every year. The epithelial-to-mesenchymal transition (EMT) program plays an important role in OSCC progression and metastasis therefore contributing to a poor prognosis in patients with advanced disease. Transforming growth factor beta (TGF-ß) is a powerful inducer of EMT thereby increasing cancer cell aggressiveness. Here, we aimed at identifying RNA-binding proteins (RBPs) that affect TGF-ß-induced EMT. To this end we treated oral cancer cells with TGF-ß and identified a total of 643 significantly deregulated protein-coding genes in response to TGF-ß. Of note, 19 genes encoded RBPs with NANOS1 being the most downregulated RBP. Subsequent cellular studies demonstrated a strong inhibitory effect of NANOS1 on migration and invasion of SAS oral cancer cells. Further mechanistic studies revealed an interaction of NANOS1 with the TGF-ß receptor 1 (TGFBR1) mRNA, leading to increased decay of this transcript and a reduced TGFBR1 protein expression, thereby preventing downstream TGF-ß/SMAD signaling. In summary, we identified NANOS1 as negative regulator of TGF-ß signaling in oral cancer cells.

Apigenin suppresses the low oxaliplatin-induced epithelial-mesenchymal transition in oral squamous cell carcinoma cells via LINC00857

Background

Apigenin is a natural flavonoid compound with proven antitumor activity. However, its precise underlying pharmacological mechanism remains unclear. Oxaliplatin (OXA) is commonly utilized for cancer treatment as a platinum-based chemotherapy drug. However, the utilization of low-dose OXA carries the risk of inducing epithelial-mesenchymal transition (EMT) in cancer cells and promoting tumor metastasis, thereby giving rise to potential side effects. The purpose of this study is to investigate the synergistic inhibitory effect of apigenin and OXA and its potential mechanism.

Methods

HSC-3 cells of oral squamous carcinoma cells (OSCCs) were divided into control, apigenin-treated and co-treated groups. A wound healing assay was conducted to assess alterations in cellular motility and migration, an invasion assay was performed to assess invasiveness, and a three-dimensional culture assay was employed to evaluate angiogenic capacity. Cultured cells were utilized for total DNA extraction, followed by reverse transcription. Relative RNA levels were obtained, and quantitative polymerase chain reaction (qPCR) analysis was conducted to assess the efficiency of LINC00857 expression.

Results

The administration of a low dose of OXA promoted the migratory, invasive, and angiogenic capabilities of HSC-3 cells, while also regulating EMT-associated molecular markers to facilitate the process of EMT. The inhibitory impact on OSCC proliferation was enhanced by the synergistic effect of apigenin and OXA. Furthermore, the tumor-promoting effects induced by low-dose OXA were notably suppressed through LINC00857.

Conclusions

Evidence from this study indicates that apigenin can effectively suppress the metastasis of OSCC cancer cells induced by low-dose OXA through inhibiting the level of LINC00857, suggesting a promising therapeutic strategy.

CSChighE-cadherinlow immunohistochemistry panel predicts poor prognosis in oral squamous cell carcinoma

Identifying marker combinations for robust prognostic validation in primary tumour compartments remains challenging. We aimed to assess the prognostic significance of CSC markers (ALDH1, CD44, p75NTR, BMI-1) and E-cadherin biomarkers in OSCC. We analysed 94 primary OSCC and 67 metastatic lymph node samples, including central and invasive tumour fronts (ITF), along with clinicopathological data. We observed an increase in ALDH1+/CD44+/BMI-1- tumour cells in metastatic lesions compared to primary tumours. Multivariate analysis highlighted that elevated p75NTR levels (at ITF) and reduced E-cadherin expression (at the tumour centre) independently predicted metastasis, whilst ALDH1high exhibited independent predictive lower survival at the ITF, surpassing the efficacy of traditional tumour staging. Then, specifically at the ITF, profiles characterized by CSChighE-cadherinlow (ALDH1highp75NTRhighE-cadherinlow) and CSCintermediateE-cadherinlow (ALDH1 or p75NTRhighE-cadherinlow) were significantly associated with worsened overall survival and increased likelihood of metastasis in OSCC patients. In summary, our study revealed diverse tumour cell profiles in OSCC tissues, with varying CSC and E-cadherin marker patterns across primary tumours and metastatic sites. Given the pivotal role of reduced survival rates as an indicator of unfavourable prognosis, the immunohistochemistry profile identified as CSChighE-cadherinlow at the ITF of primary tumours, emerges as a preferred prognostic marker closely linked to adverse outcomes in OSCC.

AKR1B10 accelerates glycolysis through binding HK2 to promote the malignant progression of oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) remains a rampant oral cavity neoplasm with high degree of aggressiveness. Aldo-keto reductase 1B10 (AKR1B10) that is an oxidoreductase dependent on nicotinamide adenine dinucleotide phosphate (NADPH) has been introduced to possess prognostic potential in OSCC. The present work was focused on specifying the involvement of AKR1B10 in the process of OSCC and its latent functional mechanism.

METHODS

AKR1B10 expression in OSCC tissues and cells were detected by RT-qPCR and Western blot analysis. CCK-8 method, EdU staining, wound healing and transwell assays respectively assayed cell viability, proliferation, migration and invasion. Immunofluorescence staining and Western blot evaluated epithelial mesenchymal transition (EMT). Adenosine triphosphate (ATP) contents, glucose consumption and extracellular acidification rate (ECAR) were measured by relevant commercially available kits and Seahorse XF96 Glycolysis Analyzer, severally. The expressions of proteins associated with metastasis and glycolysis were examined with Western blot. Co-IP assay confirmed the binding between AKR1B10 and hexokinase 2 (HK2).

RESULTS

It was observed that AKR1B10 expression was increased in OSCC tissues and cells. After AKR1B10 was knocked down, the proliferation, migration, invasion and EMT of OSCC cells were all hampered. Additionally, AKR1B10 silencing suppressed glycolysis and bound to HK2 in OSCC cells. Up-regulation of HK2 partially abolished the hampered glycolysis, proliferation, migration, invasion and EMT of AKR1B10-silenced OSCC cells.

CONCLUSION

To sum up, AKR1B10 could bind to HK2 to accelerate glycolysis, thereby facilitating the proliferation, migration, invasion and EMT of OSCC cells.

Role of prognostic gene DKK1 in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most common squamous cell carcinomas of the head and neck. The morbidity and mortality rates of OSCC have increased in recent years. However, the pathogenesis of this disease remains unknown. The present study aimed to identify predictive biomarkers and therapeutic targets for OSCC. Bioinformatics screening of differentially expressed genes in OSCC was performed based on data from The Cancer Genome Atlas and Gene Expression Omnibus databases. Dickkopf Wnt signaling pathway inhibitor 1 (DKK1) was identified to be associated with survival, tumor immunity and DNA repair in OSCC. Furthermore, the effects of DKK1 were evaluated by the knockdown of DKK1 in two OSCC cell lines. The proliferation, clonogenicity, migration and invasion of the cells were assessed in vitro using Cell Counting Kit-8, colony formation, wound healing and Transwell assays, respectively, and were found to be inhibited by DKK1 knockdown. The present study suggests that DKK1 may be used in the prognosis of patients with OSCC and that targeting DKK1 is a potential strategy for OSCC therapy.

Potential role of epithelial-mesenchymal transition induced by periodontal pathogens in oral cancer

With the increasing incidence of oral cancer in the world, it has become a hotspot to explore the pathogenesis and prevention of oral cancer. It has been proved there is a strong link between periodontal pathogens and oral cancer. However, the specific molecular and cellular pathogenic mechanisms remain to be further elucidated. Emerging evidence suggests that periodontal pathogens-induced epithelial-mesenchymal transition (EMT) is closely related to the progression of oral cancer. Cells undergoing EMT showed increased motility, aggressiveness and stemness, which provide a pro-tumour environment and promote malignant metastasis of oral cancer. Plenty of studies proposed periodontal pathogens promote carcinogenesis via EMT. In the current review, we discussed the association between the development of oral cancer and periodontal pathogens, and summarized various mechanisms of EMT caused by periodontal pathogens, which are supposed to play an important role in oral cancer, to provide targets for future research in the fight against oral cancer.

Mitochondria in oral cancer stem cells: Unraveling the potential drug targets for new and old drugs

Head and neck cancer is a major health problem worldwide, with most cases arising in the oral cavity. Oral squamous cell carcinoma (OSCC) is the most common type of oral cancer, accounting for over 90% of all cases. Compared to other types of cancer, OSCC, has the worse prognosis, with a 5-year survival rate of 50%. Additionally, OSCC is characterized by a high rate of resistance to chemotherapy treatment, which may be partly explained by the presence of cancer stem cells (CSC) subpopulation. CSC can adapt to harmful environmental condition and are highly resistant to both chemotherapy and radiotherapy treatments, thus contributing to tumor relapse. The aim of this review is to highlight the role of mitochondria in oral CSC as a potential target for oral cancer treatment. For this purpose, we reviewed some fundamental aspects of the most validated protein markers of stemness, autophagy, the mitochondrial function and energy metabolism in oral CSC. Moreover, a discussion will be made on why energy metabolism, especially oxidative phosphorylation in CSC, may offer such a diverse source of original pharmacological target for new drugs. Finally, we will describe some drugs able to disturb mitochondrial function, with emphasis on those aimed to interrupt the electron transport chain function, as novel therapeutic strategies in multidrug-resistant oral CSC. The reutilization of old drugs approved for clinical use as new antineoplastics, in cancer treatment, is also matter of revision.

Decoding the host-pathogen interspecies molecular crosstalk during oral candidiasis in humans: an in silico analysis

Introduction: The objective of this study is to investigate the interaction between Candida albicans and human proteins during oral candidiasis, with the aim of identifying pathways through which the pathogen subverts host cells. Methods: A comprehensive list of interactions between human proteins and C. albicans was obtained from the Human Protein Interaction Database using specific screening criteria. Then, the genes that exhibit differential expression during oral candidiasis in C. albicans were mapped with the list of human-Candida interactions to identify the corresponding host proteins. The identified host proteins were further compared with proteins specific to the tongue, resulting in a final list of 99 host proteins implicated in oral candidiasis. The interactions between host proteins and C. albicans proteins were analyzed using the STRING database, enabling the construction of protein-protein interaction networks. Similarly, the gene regulatory network of Candida proteins was reconstructed using data from the PathoYeastract and STRING databases. Core module proteins within the targeted host protein-protein interaction network were identified using ModuLand, a Cytoscape plugin. The expression levels of the core module proteins under diseased conditions were assessed using data from the GSE169278 dataset. To gain insights into the functional characteristics of both host and pathogen proteins, ontology analysis was conducted using Enrichr and YeastEnrichr, respectively. Result: The analysis revealed that three Candida proteins, HHT21, CYP5, and KAR2, interact with three core host proteins, namely, ING4 (in the DNMT1 module), SGTA, and TOR1A. These interactions potentially impair the immediate immune response of the host against the pathogen. Additionally, differential expression analysis of fungal proteins and their transcription factors in Candida-infected oral cell lines indicated that Rob1p, Tye7p, and Ume6p could be considered candidate transcription factors involved in instigating the pathogenesis of oral candidiasis during host infection. Conclusion: Our study provides a molecular map of the host-pathogen interaction during oral candidiasis, along with potential targets for designing regimens to overcome oral candidiasis, particularly in immunocompromised individuals.

Role of desmosomal components in the initiation and metastasis of oral cancer-A review

Desmosomes are composed of a number of proteins, including cadherins, armadillo proteins and plakoplilins, which are responsible for mediating cell-cell adhesion. Cadherins are transmembrane proteins that bind to each other on adjacent cells, forming a strong adhesive bond between the cells. In normal tissues, desmosomes help to maintain the structural integrity of the tissue by holding the cells together. During carcinogenesis, the structure and function of desmosomes may be altered. For example, in oral cancer, the expression of certain cadherins may be increased, leading to increased cell-cell adhesion and a more cohesive tumour mass. This may contribute to the ability of cancer cells to evade the immune system and resist chemotherapy. In addition to their role in cell adhesion, desmosomes also play a role in cell signaling. The proteins that make up desmosomes can interact with signaling pathways that regulate cell proliferation, migration and survival. Dysregulation of these pathways may contribute to the development and progression of oral cancer. There is also evidence that desmosomes may be involved in the process of invasion and metastasis, which is the spread of cancer cells from the primary tumour to other parts of the body. Cancer cells that have disrupted or abnormal desmosomes may be more likely to migrate and invade other tissues. Overall, desmosomes appear to be important in the development and progression of oral cancer. Further research is needed to fully understand the role of these cell-cell junctions in the disease and to identify potential therapeutic targets.

Prognostic impact of the loss of E-cadherin and de novo expression of N-cadherin at the invasive front of primary and recurrent oral squamous cell carcinoma

The epithelial-mesenchymal transition (EMT) is a biological mechanism in multiple pathophysiological diseases. Related alterations in cadherin expression play a crucial role in carcinogenesis, progression, angiogenesis, and immune response. EMT cells exhibit a transition from an epithelial to a mesenchymal phenotype (cadherin-switch). This process is characterized by the de novo development of N-cadherin (N-CAD), which replaces E-cadherin (E-CAD) and signifies an increased migratory capacity and malignant transformation. The cadherin switch is a hallmark of EMT and has been studied in various cancer entities. We predicted that the cadherin switch in the primary and recurrent oral squamous cell carcinoma (re-OSCC) tissues is an inherent characteristic of the tumor, affects the biologic behavior, and further reflects the post-recurrence survival outcome of these patients. Survival outcome was analyzed by calculating the post-recurrence survival of the high-risk group and correlating the standardized h-score-based IHC expression of both cadherin types with the clinical follow-up. 94 patients with re-OSCC were observed within the cohort. Tissue samples from both primary and recurring tumors were collected. There was a significant association between loss of E-CAD expression and both oral cancer-specific and overall survival, (HR=2.72, CI:1.50-4.95, p=0.001) and (HR=3.84, CI:1.93-7.63, p=0.001), respectively, for expression loss higher than 60%. There was no statistically significant correlation between N-CAD de novo expression and Overall, oral cancer-specific and disease-free post-recurrence survival. The current study clearly shows that cadherin-switch, identified as E-CAD loss and N-CAD de novo expression in the invasion front of a re-OSCC, appears to be an inherent histological hallmark that does not change from primary manifestation to recurrence within the same tumor, regardless of the form of adjuvant therapy used for the primary tumor. The loss of E-CAD expression in re-OSCC is an independent risk factor for poor survival, and may be used to stratify therapy and de/escalate the multimodal treatment.

Noncoding RNAs in oral cancer

Oral cancer (OC) is the most prevalent subtype of cancer arising in the head and neck region. OC risk is mainly attributed to behavioral risk factors such as exposure to tobacco and excessive alcohol consumption, and a lesser extent to viral infections such as human papillomaviruses and Epstein-Barr viruses. In addition to these acquired risk factors, heritable genetic factors have shown to be associated with OC risk. Despite the high incidence, biomarkers for OC diagnosis are lacking and consequently, patients are often diagnosed in advanced stages. This delay in diagnosis is reflected by poor overall outcomes of OC patients, where 5-year overall survival is around 50%. Among the biomarkers proposed for cancer detection, noncoding RNA (ncRNA) can be considered as one of the most promising categories of biomarkers due to their role in virtually all cellular processes. Similar to other cancer types, changes in expressions of ncRNAs have been reported in OC and a number of ncRNAs have diagnostic, prognostic, and therapeutic potential. Moreover, some ncRNAs are capable of regulating gene expression by various mechanisms. Therefore, elucidating the current literature on the four main types of ncRNAs namely, microRNA, lncRNA, snoRNA, piwi-RNA, and circular RNA in the context of OC pathogenesis is timely and would enable further improvements and innovations in diagnosis, prognosis, and treatment of OC. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.

Critical roles of adherens junctions in diseases of the oral mucosa

The oral cavity is directly exposed to a variety of environmental stimuli and contains a diverse microbiome that continuously interacts with the oral epithelium. Therefore, establishment and maintenance of the barrier function of the oral mucosa is of paramount importance for its function and for the body's overall health. The adherens junction is a cell-cell adhesion complex that is essential for epithelial barrier function. Although a considerable body of work has associated barrier disruption with oral diseases, the molecular underpinnings of these associations have not been equally investigated. This is critical, since adherens junction components also possess significant signaling roles in the cell, in addition to their architectural ones. Here, we summarize current knowledge involving adherens junction components in oral pathologies, such as cancer and oral pathogen-related diseases, while we also discuss gaps in the knowledge and opportunities for future investigation of the relationship between adherens junctions and oral diseases.

Epithelial-mesenchymal transition in cancer stem cells: Therapeutic implications

Cancer stem cells (CSCs) are cancer cells that possess characteristics associated with normal stem cells, specifically the ability to give rise to all cell types found in a particular cancer sample. CSCs may generate tumors through the processes of self-renewal and differentiation into multiple cell types. CSCs present in tumors are normally resistant to conventional therapy and may contribute to tumor recurrence. Tumor residuals present after therapy, with CSCs enrichment, have all the hallmarks of epithelial-mesenchymal transition (EMT). In this review, we discuss the relationship between EMT and CSCs in cancer progression and its therapeutic implications in oral squamous cell carcinoma.

Different molecular weights of hyaluronan research in knee osteoarthritis: A state-of-the-art review

Osteoarthritis (OA), the most common form of arthritis, is characterized by progressive cartilage destruction, concomitant adaptive osteogenesis, and loss of joint function. The progression of OA with aging is associated with a decrease in native hyaluronan (HA, hyaluronate or hyaluronic acid) with a high molecular weight (HMW) in synovial fluid and a subsequent increase in lower MW HA and fragments. As HMW HA possesses numerous biochemical and biological properties, we review new molecular insights into the potential of HA to modify OA processes. Different MWs in the formulation of products appear to have varying effects on knee OA (KOA) pain relief, improved function, and postponing surgery. In addition to the safety profile, more evidence indicates that intraarticular (IA) HA administration may be an effective option to treat KOA, with a particular emphasis on the use of HA with fewer injections of higher MW, including potential applications of HA of very HMW. We also analyzed published systemic reviews and meta-analyses of IA HA in treating KOA in order to discuss their conclusions and consensus statements. According to its MW, HA may offer a simple way to refine therapeutic information in selective KOA.

Melatonin: Emerging Player in the Management of Oral Cancer

Oral cancer (OC) has emerged as a major medical and social issue in many industrialized nations due to the high death rate. It is becoming increasingly common in people under the age of 45, although the underlying causes and mechanisms of this increase remain unclear. Melatonin, as a pleiotropic hormone, plays a pivotal role in a wide variety of cellular and physiological functions. Mounting evidence supports melatonin's ability to modify/influence oral carcinogenesis, help in the reduction of the incidence of OC, and increase chemo- and radiosensitivity. Despite its potential anti-carcinogenic effects, the precise function of melatonin in the management of OC is not well understood. This review summarizes the current knowledge regarding melatonin function in anti-carcinogenesis mechanisms for OC. In addition, clinical assessment and the potential therapeutic utility of melatonin in OC are discussed. This review will provide a basis for researchers to create new melatonin-based personalized medicines for treating and preventing OC.

Molecular Crosstalk between the Immunological Mechanism of the Tumor Microenvironment and Epithelial–Mesenchymal Transition in Oral Cancer

Oral cancer is a significant non-communicable disease affecting both emergent nations and developed countries. Squamous cell carcinoma of the head and neck represent the eight major familiar cancer types worldwide, accounting for more than 350,000 established cases every year. Oral cancer is one of the most exigent tumors to control and treat. The survival rate of oral cancer is poor due to local invasion along with recurrent lymph node metastasis. The tumor microenvironment contains a different population of cells, such as fibroblasts associated with cancer, immune-infiltrating cells, and other extracellular matrix non-components. Metastasis in a primary site is mainly due to multifaceted progression known as epithelial-to-mesenchymal transition (EMT). For the period of EMT, epithelial cells acquire mesenchymal cell functional and structural characteristics, which lead to cell migration enhancement and promotion of the dissemination of tumor cells. The present review links the tumor microenvironment and the role of EMT in inflammation, transcriptional factors, receptor involvement, microRNA, and other signaling events. It would, in turn, help to better understand the mechanism behind the tumor microenvironment and EMT during oral cancer.

Identification of Nine M6A-Related Long Noncoding RNAs as Prognostic Signatures Associated with Oxidative Stress in Oral Cancer Based on Data from The Cancer Genome Atlas

Objective

Although the expression of long noncoding RNAs (lncRNAs) and N6-methyladenosine (M6A) is correlated with different tumors, it remains unclear how M6A-related lncRNA functioning affects the initiation and progression of oral squamous cell carcinoma (OSCC).

Materials and Methods

Gene expression and clinical data were retrieved from The Cancer Genome Atlas. The prognostic value of M6A-related lncRNAs was determined using univariate Cox regression analyses. Gene set enrichment analysis of OSCC patient clusters revealed the pathways that elucidate the mechanism. Furthermore, a risk-based model was established. The difference in the overall survival (OS) between groups, including low-/high-risk groups, was determined by Kaplan-Meier analysis. Relationships among immune cells, clusters, clinicopathological characteristics, and risk scores were explored.

Results

Among 1,080 M6A-related lncRNAs, 36 were prognosis-related. Patients with OSCC were divided into two clusters. T stage and the pathological grade were noticeably lower in cluster 2 than in cluster 1. Epithelial-mesenchymal transition showed greater enrichment in cluster 1. Nine hub M6A-related lncRNAs were identified for the model of risk score for predicting OSCC prognosis. The OS was longer in patients with a low-risk score than in patients with a high-risk score. The risk score was an independent prognostic factor of OSCC and was associated with the infiltration of different immune cells. T stages and the American Joint Committee on Cancer (AJCC) stages were more advanced in the high-risk score group than in the low-risk score group. Finally, expression correlation analysis showed that the risk score is associated with the expression of oxidative stress markers.

Conclusion

M6A-related lncRNAs play an important role in OSCC progression. Immune cell infiltration was related to the risk score model in OSCC and could accurately predict OSCC prognosis.

Risk Factors of Microscopically Tumor-Free Surgical Margins for Recurrence and Survival of Oral Squamous Cell Carcinoma Patients

Objectives

The concept of adequate surgical margins remains controversial in oral squamous cell carcinoma (OSCC) surgery. This study aimed to identify surgical margin-related indicators that might impact recurrence and survival of OSCC patients.

Materials and Methods

Histopathological examination was performed using hematoxylin-eosin-stained surgical margin tissue sections in 235 OSCC patients. Axin2 and Snail expression at the surgical margin was detected by immunohistochemistry. The impact of the Axin2-Snail cascade on tumorigenesis of the immortalized human oral keratinocyte (IHOK) line was investigated in vivo.

Results

The width and dysplasia of surgical margins were not significantly associated with the outcome of OSCC patients. In a multivariate analysis using variable clinicopathologic factors and with Axin2 and Snail expression as cofactors, higher age (hazard ratio [HR]:1.050; P=0.047), Axin2 (HR:6.883; P=0.014), and Snail abundance (HR:5.663; P=0.009) had independent impacts on worsened overall survival. Similarly, lesion site in retromolar trigone (HR:4.077; P=0.010), upper (HR:4.332; P=0.005) and lower gingiva (HR:3.545; P=0.012), presence of extranodal extension (HR:9.967; P<0.001), perineural invasion (HR:3.627; P=0.024), and Snail abundance (HR:3.587; P<0.001) had independent impacts on worsened recurrence-free survival. Furthermore, Axin2 knockdown induced decreased Snail expression and attenuated tumorigenesis in the IHOK line.

Conclusion

Histopathological examination of surgical margins may not be reliable to predict OSCC patient outcome. Molecular analysis may provide a more accurate risk assessment of surgical margins in OSCC. In particular, Axin2 and Snail are potential predictive biomarkers for the risk assessment of surgical margins in OSCC.

Single-cell sequencing: a promising approach for uncovering the mechanisms of tumor metastasis

Single-cell sequencing (SCS) is an emerging high-throughput technology that can be used to study the genomics, transcriptomics, and epigenetics at a single cell level. SCS is widely used in the diagnosis and treatment of various diseases, including cancer. Over the years, SCS has gradually become an effective clinical tool for the exploration of tumor metastasis mechanisms and the development of treatment strategies. Currently, SCS can be used not only to analyze metastasis-related malignant biological characteristics, such as tumor heterogeneity, drug resistance, and microenvironment, but also to construct metastasis-related cell maps for predicting and monitoring the dynamics of metastasis. SCS is also used to identify therapeutic targets related to metastasis as it provides insights into the distribution of tumor cell subsets and gene expression differences between primary and metastatic tumors. Additionally, SCS techniques in combination with artificial intelligence (AI) are used in liquid biopsy to identify circulating tumor cells (CTCs), thereby providing a novel strategy for treating tumor metastasis. In this review, we summarize the potential applications of SCS in the field of tumor metastasis and discuss the prospects and limitations of SCS to provide a theoretical basis for finding therapeutic targets and mechanisms of metastasis.

ET-1 Promotes Epithelial-Mesenchymal Transition in Oral Squamous Cell Carcinoma Cells via the microRNA-489-3p /TWIST Axis

OBJECTIVE

Oral squamous cell carcinoma (OSCC) constitutes almost 90% of head and neck malignancies and has a poor prognosis. To improve the efficacy of OSCC therapy, it is of great significance to explore other therapy for OSCC. Endothelin-1 (ET-1), a potent vasoconstrictor peptide, is implicated in cancer pathogenesis. Moreover, ET-1 promotes epithelial-mesenchymal transition (EMT) during the development of human cancers. We further to found that ET-1 exposure induced EMT in human squamous cell carcinoma cell lines SCC4 and SAS, by enhancing the expression of EMT biomarkers N-cadherin and vimentin and reducing E-cadherin expression via upregulation of the transcription factor TWIST.

MATERIALS AND METHODS

Cell motility was examined by migration, invasion and wound-healing assays. Quantitative real time polymerase chain reaction (q-PCR), and promoter assays confirmed the inhibitory effects of ET-1 on miRNAs expression in oral cancer cells. We demonstrate an intravenous injection model of lung metastasis followed by an advanced method for quantifying metastatic tumor using image analysis software.

RESULTS

In addition, ET-1/ETAR reduced levels of microRNA-489-3p (miR-489-3p), a transcriptional repressor of TWIST. We have identified a novel bypass mechanism through which ET-1/ETAR are involved in TWIST signaling and downregulate miR-489-3p expression, enabling OSCC cells to acquire the EMT phenotype. Notably, ET-1 knockdown dramatically decreased levels of EMT markers and cell migration potential.

CONCLUSION

The role of ET-1 in OSCC progression is supported by our findings from an in vivo murine model of OSCC. ET-1 may therefore represent a novel molecular therapeutic target in OSCC metastasis.

Understanding the complex pathogenesis of oral cancer: A comprehensive review

The pathogenesis of oral cancer is a complex and multifactorial process that requires a deep understanding of the underlying mechanisms involved in the development and progress of malignancy. The ever-improving comprehension of the diverse molecular characteristics of cancer, the genetic and epigenetic alterations of tumor cells, and the complex signaling pathways that are activated and frequently cross talk open up promising horizons for the discovery and application of diagnostic molecular markers and set the basis for an era of individualized management of the molecular defects underlying and governing oral premalignancy and cancer. The purpose of this article is to review the key molecular concepts that are implicated in oral carcinogenesis, especially focusing on oral squamous cell carcinoma, and to review selected biomarkers that play a substantial role in controlling the so-called "hallmarks of cancer," with special reference to recent advances that shed light on their deregulation during the different steps of oral cancer development and progression.

Identification of lymphocyte cell-specific protein-tyrosine kinase (LCK) as a driver for invasion and migration of oral cancer by tumor heterogeneity exploitation

BACKGROUND

Cancer metastases are the main cause of lethality. The five-year survival rate for patients diagnosed with advanced stage oral cancer is 30%. Hence, the identification of novel therapeutic targets is an urgent need. However, tumors are comprised of a heterogeneous collection of cells with distinct genetic and molecular profiles that can differentially promote metastasis making therapy development a challenging task. Here, we leveraged intratumoral heterogeneity in order to identify drivers of cancer cell motility that might be druggable targets for anti-metastasis therapy.

METHODS

We used 2D migration and 3D matrigel-based invasion assays to characterize the invasive heterogeneity among and within four human oral cancer cell lines in vitro. Subsequently, we applied mRNA-sequencing to map the transcriptomes of poorly and strongly invasive subclones as well as primary tumors and matched metastasis.

RESULTS

We identified SAS cells as a highly invasive oral cancer cell line. Clonal analysis of SAS yielded a panel of 20 subclones with different invasive capacities. Integrative gene expression analysis identified the Lymphocyte cell-specific protein-tyrosine kinase (LCK) as a druggable target gene associated with cancer cell invasion and metastasis. Inhibition of LCK using A-770041 or dasatinib blocked invasion of highly aggressive SAS cells. Interestingly, reduction of LCK activity increased the formation of adherens junctions and induced cell differentiation.

CONCLUSION

Analysis of invasive heterogeneity led to the discovery of LCK as an important regulator of motility in oral cancer cells. Hence, small molecule mediated inhibition of LCK could be a promising anti-metastasis therapy option for oral cancer patients.

Comparison of Androgen Receptor, VEGF, HIF-1, Ki67 and MMP9 Expression between Non-Metastatic and Metastatic Stages in Stromal and Tumor Cells of Oral Squamous Cell Carcinoma

Objectives: Oral squamous cell carcinoma (OSCC) is the most common oral malignancy with low survival as it is very often diagnosed at an advanced stage, which is why the accurate profiling of the tumor is essential. The aim of this study was to, for the first time, compare in OSCC the frequency of AR, VEGF, MMP9, HiF1beta and Ki67 between the non-metastatic and metastatic disease. Materials and Methods: In the study, 96 non-metastatic and 91 metastatic OSCC patients were analysed for AR, VEGF, MMP9, HiF1beta and Ki67 levels by immunohistochemistry. Results: All of the tested biomarkers significantly differed between non-metastatic and metastatic disease. A significant association was found between >/=20% AR positive epithelium cells in cytoplasm, Ki67 and VEGF in cancer stroma. Ki67, HiF1beta, VEGF and MMP9 were significantly associated with TNM stages. Conclusion: Our results show for the first time an interplay between AR, VEGF, MMP9, HiF1beta and Ki67 in OSCC which may contribute to better diagnostics and therapy selection.

lncRNA‑CASC15 promotes osteosarcoma proliferation and metastasis by regulating epithelial‑mesenchymal transition via the Wnt/β‑catenin signaling pathway

Osteosarcoma (OS) is a rare type of tumor and mostly occurs in children and adolescents. Approximately 10–25% of patients with OS have lung metastases, and lung damage caused by lung metastasis is the main cause of mortality. Therefore, studying the growth and metastasis of OS is key in reducing OS mortality and improving prognosis. The expression of long non-coding RNA (lncRNA) cancer susceptibility 15 (CASC15) in OS patients or OS cell lines were quantified by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The expression of vimentin, E-cadherin, N-cadherin, and cyclin D were detected by RT-qPCR and western blotting. Mice were injected with OS cell lines via the tail vein to observe tumor formation in the lung. CCK-8 and EdU assays were utilized to evaluate cell proliferation. Both Ttranswell assay and cell scratch test detected cell migration. The results revealed that lncRNA-CASC15 was highly expressed in clinical samples and OS cells. In vitro verification experiments revealed that CASC15 promoted the growth of OS cells. Rescue experiments demonstrated that CASC15 affected the cell cycle by activating the Wnt/β-catenin pathway, thereby promoting cell proliferation. Furthermore, the transfection dose test indicated that lentiviruses expressing various doses of CASC15-overexpression (oe-CASC15) altered the proliferation and migration status of OS cells. CASC15 promoted OS cell metastasis both in vivo and in vitro. The overexpression of CASC15 revealed that the occurrence of metastasis was also related to the Wnt/β-catenin pathway. The western blotting results revealed that CASC15 could lead to β-catenin entering the nucleus via the Wnt pathway to promote the epithelial-mesenchymal transition (EMT) of OS cells. To sum up, CASC15 promoted the proliferation of OS cells in vitro and the growth of OS xenograft tumors in vivo. Moreover, CASC15 promoted the entry of β-catenin into the nucleus, thus activating the Wnt pathway and subsequently promoting the EMT of OS cells.

Trophoblast cell surface antigen 2 expression predicts outcome in oral squamous cell carcinomas

BACKGROUND

Trophoblast cell surface antigen 2 (TROP2) has unclear clinical role in oral squamous cell carcinomas (OSCC). Here, we investigated the association of TROP2 immunoexpression with clinicopathological parameters and survival of OSCC patients.

SUBJECTS AND METHODS

Cancer-specific survival (CSS) and disease-free survival (DFS) were assessed in a cohort composed of 266 OSCC. An independent cohort with 88 OSCC samples matched with the normal oral tissue, as well as 17 metastatic lymph nodes, was used for validation.

RESULTS

Multivariate analysis showed TROP2 as an independent marker of favorable prognosis for both CSS (HR: 0.60, 95% CI: 0.40-0.90, p = .01) and DFS (HR: 0.57, 95% CI: 0.36-0.89, p = .01). Furthermore, TROP2 protein expression was significantly higher in morphologically normal tissues compared to primary tumors (p < .0001) and lymph node metastases (p = .001), and it was significantly associated with CSS (HR: 0.26, 95% CI: 0.09-0.74, p = .008) in the validation cohort. A pooled mRNA analysis performed on the Oncomine™ database confirmed the underexpression in OSCC compared with normal tissues (p = .014).

CONCLUSIONS

In summary, our results point to a favorable prognostic significance of TROP2 overexpression in a large cohort of oral cancer patients, suggesting it as an attractive clinical marker.

RNA-Binding Proteins as Regulators of Migration, Invasion and Metastasis in Oral Squamous Cell Carcinoma

Nearly 7.5% of all human protein-coding genes have been assigned to the class of RNA-binding proteins (RBPs), and over the past decade, RBPs have been increasingly recognized as important regulators of molecular and cellular homeostasis. RBPs regulate the post-transcriptional processing of their target RNAs, i.e., alternative splicing, polyadenylation, stability and turnover, localization, or translation as well as editing and chemical modification, thereby tuning gene expression programs of diverse cellular processes such as cell survival and malignant spread. Importantly, metastases are the major cause of cancer-associated deaths in general, and particularly in oral cancers, which account for 2% of the global cancer mortality. However, the roles and architecture of RBPs and RBP-controlled expression networks during the diverse steps of the metastatic cascade are only incompletely understood. In this review, we will offer a brief overview about RBPs and their general contribution to post-transcriptional regulation of gene expression. Subsequently, we will highlight selected examples of RBPs that have been shown to play a role in oral cancer cell migration, invasion, and metastasis. Last but not least, we will present targeting strategies that have been developed to interfere with the function of some of these RBPs.