Invasion-Related Factors as Potential Diagnostic and Therapeutic Targets in Oral Squamous Cell Carcinoma-A Review

Capnocytophaga gingivalis is a potential tumor promotor in oral cancer

OBJECTIVES

To investigate the role of oral microbiome in promoting oral squamous cell carcinoma (OSCC) development.

MATERIALS AND METHODS

We investigated the salivary microbiome of 108 controls and 70 OSCC cases by16S rRNA gene sequencing and detected the fluorescence signal of OSCC-related pathological bacteria by fluorescence in situ hybridization assay (FISH). The invasion and migration assays were used to show the differences of invasive and migrative abilities between control and experimental groups. Quantitative real-time PCR and Western blotting were used to verify the epithelial-to-mesenchymal transition (EMT).

RESULTS

In our study, the overall microbiome abundance and composition were richer in the 108 controls than in the 70 OSCC cases. We demonstrated that Streptococcus, Capnocytophaga, Peptostreptococcus, and Lactobacillus were highly abundant in the saliva of OSCC patients by 16S rDNA sequencing and FISH. Moreover, we found that Capnocytophaga gingivalis (C. gingivalis) was highly presented in OSCC tissues by FISH. We focused on C. gingivalis and found that its supernatant induced OSCC cells to undergo EMT, causing the cells to acquire a mesenchymal phenotype associated with highly invasive and metastatic properties.

CONCLUSION

Taken together, these results indicated that C. gingivalis might invade OSCC tissues and played an important role in OSCC by promoting OSCC invasion and metastasis by inducing EMT. Hence, the role of C. gingivalis in cancer progression revealed a new direction for the research of OSCC.

Machine learning modeling and prognostic value analysis of invasion-related genes in cutaneous melanoma

In this study, we aimed to develop an invasion-related risk signature and prognostic model for personalized treatment and prognosis prediction in skin cutaneous melanoma (SKCM), as invasion plays a crucial role in this disease. We identified 124 differentially expressed invasion-associated genes (DE-IAGs) and selected 20 prognostic genes (TTYH3, NME1, ORC1, PLK1, MYO10, SPINT1, NUPR1, SERPINE2, HLA-DQB2, METTL7B, TIMP1, NOX4, DBI, ARL15, APOBEC3G, ARRB2, DRAM1, RNF213, C14orf28, and CPEB3) using Cox and LASSO regression to establish a risk score. Gene expression was validated through single-cell sequencing, protein expression, and transcriptome analysis. Negative correlations were discovered between risk score, immune score, and stromal score using ESTIMATE and CIBERSORT algorithms. High- and low-risk groups exhibited significant differences in immune cell infiltration and checkpoint molecule expression. The 20 prognostic genes effectively differentiated between SKCM and normal samples (AUCs >0.7). We identified 234 drugs targeting 6 genes from the DGIdb database. Our study provides potential biomarkers and a risk signature for personalized treatment and prognosis prediction in SKCM patients. We developed a nomogram and machine-learning prognostic model to predict 1-, 3-, and 5-year overall survival (OS) using risk signature and clinical factors. The best model, Extra Trees Classifier (AUC = 0.88), was derived from pycaret's comparison of 15 classifiers. The pipeline and app are accessible at https://github.com/EnyuY/IAGs-in-SKCM.

Relevance of micro-RNAs and their targets as a diagnostic and prognostic marker in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) ranks sixth among all cancers in the world, affecting various sites of the oral cavity with associated several risk factors. High mortality has been associated with the presence of metastasis during the time of diagnosis and an increase in therapeutic relapses. Micro-RNAs (miRNAs) are a group of small non-coding RNAs with salient roles in the initiation and progression of cancer. The tumorigenesis of OSCC is associated with the dysregulation of several miRNAs. MicroRNAs are an area of recent interest, and numerous studies have been reported and are being undertaken to identify their role in diagnostic and prognostic value for oral cancers. Most of the miRNA processing machinery is considered to be either up-/down-regulated in OSCC, but the underlying mechanism of miRNA dysregulation and their activity as either a tumour suppressor or an oncogene in oral carcinogenesis is not yet clear. The article presents a concise review of the available current literature regarding the various miRNAs' signatures in OSCC and their role as diagnostic/prognostic biomarkers.

A Novel Tongue Squamous Cell Carcinoma Cell Line Escapes from Immune Recognition due to Genetic Alterations in HLA Class I Complex

Immune checkpoint inhibitors (ICI) have made progress in the field of anticancer treatment, but a certain number of PD-L1 negative OSCC patients still have limited benefits from ICI immuno-therapy because of primary immune evasion due to immunodeficiency. However, in existing human OSCC cell lines, cell models that can be used to study immunodeficiency have not been reported. The objective of this study was to establish a PD-L1 negative OSCC cell line, profile whether the presence of mutated genes is associated with immune deficiency, and explore its influence on the immune recognition of CD8⁺ T cells in vitro. Here, we established a novel tongue SCC cell line (WU-TSC-1), which escapes from immune recognition by antigen presentation defects. This cell line was from a female patient who lacked typical causative factors. The expression of PD-L1 was negative in the WU-TSC-1 primary tumor, transplanted tumor, cultured cells and lipopolysaccharide stimulation. Whole exome sequencing (WES) revealed that WU-TSC-1 harbored missense mutations, loss of copy number and structural variations in human leukocyte antigen (HLA) class I/II genes. The tumor mutation burden (TMB) score was high at 292.28. In addition, loss of heterozygosity at beta-2-microglobulin (B2M)-a component of all HLA class I complex allotypes-was detected. Compared with the commonly used OSCC cell lines, genetic alterations in HLA class I and B2M impeded the proteins' translation and inhibited the activation and killing effect of CD8⁺ T cells. In all, the WU-TSC-1 cell line is characterized by genetic variations and functional defects of the HLA class I complex, leading to escape from recognition by CD8⁺ T cells.

Tailored point-of-care biosensors for liquid biopsy in the field of oncology

In the field of cancer detection, technologies to analyze tumors using biomarkers circulating in fluids such as blood have developed rapidly based on liquid biopsy. A proactive approach to early cancer detection can lead to more effective treatments with minimal side effects and better long-term patient survival. However, early detection of cancer is hindered by the existing limitations of conventional cancer diagnostic methods. To enable early diagnosis and regular monitoring and improve automation, the development of integrated point-of-care (POC) and biosensors is needed. This is expected to fundamentally change the diagnosis, management, and monitoring of response to treatment of cancer. POC-based techniques will provide a way to avoid complications that occur after invasive tissue biopsy, such as bleeding, infection, and pain. The aim of this study is to provide a comprehensive view of biosensors and their clinical relevance in oncology for the detection of biomarkers with liquid biopsies of proteins, miRNA, ctDNA, exosomes, and cancer cells. The preceding discussion also illustrates the changing landscape of liquid biopsy-based cancer diagnosis through nanomaterials, machine learning, artificial intelligence, wearable devices, and sensors, many of which apply POC design principles. With the advent of sensitive, selective, and timely detection of cancer, we see the field of POC technology for cancer detection and treatment undergoing a positive paradigm shift in the foreseeable future.

miR-125b Promotes the Proliferation, Migration and Invasion of Oral Squamous Cell Carcinoma (OSCC)

miR-125b is involved in several tumors. However, miR-125b’s role in oral squamous cell carcinoma (OSCC) is unclear. Tumor tissues and oral normal mucosa tissues of OSCC patients were collected to measure miR-125b level. Oral cancer Tca8113 cells were separated into control group, miR-125b inhibitor group, and miR-125b mimics group, followed by measuring miR-125b level by real time PCR, cell survival, migration and invasion, PI3K/mTOR signaling protein level by Western blot. miR-125b was upregulated in OSCC tumor tissues and related to clinical/TNM stage, metastasis and overall survival (P < 0.05). miR-125b overexpression significantly promoted tumor cell behaviors and increased PI3K/mTOR phosphorylation (P < 0.05); while inhibiting miR-125b expression significantly inhibited tumor cell biological behaviors, and decreased PI3K/mTOR phosphorylation (P < 0.05). miR-125b level is increased in OSCC tumor tissues, which is related to clinicopathological characteristics. miR-125b overexpression promotes OSCC cell behaviors by regulating PI3K/mTOR signaling.

HMG20A was identified as a key enhancer driver associated with DNA damage repair in oral squamous cell carcinomas

Background

Oral squamous cell carcinoma (OSCC) is the main type of oral cancer. Disturbing DNA repair is an invaluable way to improve the effectiveness of tumor treatment. Here, we aimed to explore the key enhancer drivers associated with DNA damage repair in OSCC cells.

Methods

Gene Set Enrichment Analysis (GSEA), Gene Set Variation Analysis (GSVA) and Kaplan-Meier analysis were applied to explore the relationship among DNA repair-related genes expression and clinical phenotypes based on The Cancer Genome Atlas (TCGA) database. HOMER software and Integrative Genomics Viewer were applied to identify and visualize enhancers using GSE120634. Toolkit for Cistrome Data Browser was applied to predict transcription factors. Human Protein Atlas Database was used to analyze the protein levels of transcription factors in OSCC and control tissues. Seventy-two OSCC patients were included in this study. qRT-PCR was used to detect transcription factor expression in OSCC and adjacent control tissues collected in this study. qRT-PCR and ChIP-qPCR were used to verify the binding of transcription factors to enhancers, and regulation of target genes transcription. Transcription factor knockdown and control cells were treated with cisplatin. CCK8 was used to detect cell viability and proliferation. Western blotting was implemented to detect the levels of DNA repair-related proteins. Transwell assay was used to detect cell invasion.

Results

DNA repair was positively associated with the OSCC metastatic phenotype. Patients in the cluster with high expression of DNA repair-related genes had a worse prognosis and a higher proportion of advanced stage, low-differentiation, alcohol consumption and smoking compared to the cluster with low DNA repair-related gene expression. Seventeen metastasis-specific enhancer-controlled upregulated DNA repair-related genes, with the top two upregulated genes being ADRM1 26 S proteasome ubiquitin receptor (ADRM1) and solute carrier family 12 member 7 (SLC12A7) were screened. High mobility group 20 A (HMG20A) was the key prognostic enhancer driver regulating metastasis-specific DNA repair-related genes, with higher expression in OSCC tissues than normal control tissues, and higher expression in metastatic OSCC tissues than non-metastatic OSCC tissues. HMG20A bound to the metastasis-specific enhancers of ADRM1 and SLC12A7, thereby promoting ADRM1 and SLC12A7 expression. Knockdown of HMG20A enhanced cisplatin sensitivity of cells, and inhibited OSCC cells from repairing DNA damage caused by cisplatin, as well as proliferation and invasion of OSCC cells.

Conclusion

HMG20A was identified as the key prognostic enhancer driver regulating DNA repair in OSCC cells, providing a new therapeutic target for OSCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02500-y.

Diversity of the Origin of Cancer Stem Cells in Oral Squamous Cell Carcinoma and Its Clinical Implications

Simple Summary

Oral squamous cell carcinoma (OSCC) histopathologically accounts for ≥90% of oral cancer. In this review article, we focus on the diversity of the origin of OSCC and also discuss cancer stem cells (CSCs). CSCs are a subset of cancer cells that occupy a very small portion of the cancer mass and have characteristics of stem cells. When gene abnormalities accumulate in somatic stem cells, those cells transform into CSCs. CSCs as the origin of cancer then autonomously grow and develop into cancer. The histopathological phenotype of cancer cells is determined by the original characteristics of the somatic stem cells and/or surrounding environment. OSCC may be divided into the following three categories with different malignancy based on the origin of CSCs: cancer from oral epithelial stem cell-derived CSCs, cancer from stem cells in salivary gland-derived CSCs, and cancer from bone marrow-derived stem cell-derived CSCs.

Abstract

Oral squamous cell carcinoma (OSCC) histopathologically accounts for ≥90% of oral cancer. Many clinicopathological risk factors for OSCC have also been proposed, and postoperative therapy is recommended in guidelines based on cancer stage and other risk factors. However, even if the standard treatment is provided according to the guidelines, a few cases rapidly recur or show cervical and distant metastasis. In this review article, we focus on the diversity of the origin of OSCC. We also discuss cancer stem cells (CSCs) as a key player to explain the malignancy of OSCC. CSCs are a subset of cancer cells that occupy a very small portion of the cancer mass and have characteristics of stem cells. When gene abnormalities accumulate in somatic stem cells, those cells transform into CSCs. CSCs as the origin of cancer then autonomously grow and develop into cancer. The histopathological phenotype of cancer cells is determined by the original characteristics of the somatic stem cells and/or surrounding environment. OSCC may be divided into the following three categories with different malignancy based on the origin of CSCs: cancer from oral epithelial stem cell-derived CSCs, cancer from stem cells in salivary gland-derived CSCs, and cancer from bone marrow-derived stem cell-derived CSCs.

Comprehensive Review on Development of Early Diagnostics on Oral Cancer with a Special Focus on Biomarkers

One of the most frequent head and neck cancers is oral cancer, with less than half of those diagnosed surviving five years. Despite breakthroughs in the treatment of many other cancers, the prognosis for people with OSCC remains dismal. The conventional methods of detection include a thorough clinical examination, biochemical investigations, and invasive biopsies. Early identification and treatment are important for a better chance of extending a patient’s life. Early diagnosis may be possible by identifying biomarkers in biological fluids. Currently, the primary method for diagnosing oral lesions is a visual oral examination; however, such a technique has certain drawbacks, as individuals are recognized after their cancer has advanced to a severe degree. The first section of this review discusses several diagnostic techniques for cancer detection, while the second section discusses the present state of knowledge about known existing predictive markers for the timely identification of malignant lesions, as well as disease activity tracking. The aim of the paper is to conduct a critical review of existing oral cancer diagnostic processes and to consider the possible application of innovative technology for early detection. This might broaden our diagnostic choices and enhance our capacity to identify and treat oral malignant tumors more effectively.

Involvement of RUVBL1 in WNT/β-Catenin Signaling in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is the most common malignant tumor of head and neck squamous cell carcinoma (HNSCC), but the causes and molecular mechanisms remain unclear. The wingless-integrated/β-catenin (WNT/β-catenin) signaling pathway plays a vital role in cancer cell proliferation, differentiation, and metastasis, including OSCC. To screen potential β-catenin-associated genes involved in OSCC, the intersection of these genes in the STRING and IMEx databases was assessed using differential expression genes (DEG) from public microarrays, and 22 were further selected to construct a β-catenin-protein interaction network. The top 14 hub genes (node degree > 10) within the network were selected. Pearson's correlation analysis showed that β-catenin expression correlated positively with the expression of 11 genes, including AR, BIRC5, CDK6, DKK1, GSK3B, MET, MITF, PARD3, RUVBL1, SLC9A3R1, and SMAD7. A heat map of overall hub gene survival was created, and elevated expression of DKK1 and RUVBL1 was associated with poor survival using the Mantel-Cox test. To identify the function of RUVBL1, colony formation assay, transwell assay, and western blotting revealed that knock-down of RUVBL1 by siRNA decreased H157 and Cal-27 cell proliferation and metastasis by inhibiting β-catenin signaling. These findings suggest that RUVBL1 may serve as a diagnostic and prognostic biomarker for OSCC, as well as a therapeutic target, and may help to uncover additional molecular mechanisms of β-catenin-driven OSCC tumorigenesis.

Phytochemically Derived Zingerone Nanoparticles Inhibit Cell Proliferation, Invasion and Metastasis in Human Oral Squamous Cell Carcinoma

Due to its aggressiveness and high mortality rate, oral cancer still represents a tough challenge for current cancer therapeutics. Similar to other carcinomas, cancerous invasion and metastasis are the most important prognostic factors and the main obstacles to therapy for human oral squamous cell carcinoma (OSCC). Fortunately, with the rise of the nanotechnical era and innovative nanomaterial fabrication, nanomaterials are widely used in biomedicine, cancer therapeutics, and chemoprevention. Recently, phytochemical substances have attracted increasing interest as adjuvants to conventional cancer therapy. The ginger phenolic compound zingerone, a multitarget pharmacological and bioactive phytochemical, possesses potent anti-inflammatory, antioxidant, and anticancer activities. In our previous study, we generated phytochemically derived zingerone nanoparticles (NPs), and documented their superior antitumorigenic effect on human hepatoma cells. In the present study, we further investigated the effects of zingerone NPs on inhibiting the invasiveness and metastasis of human OSCC cell lines. Zingerone NPs elicited significant cytotoxicity in three OSCC cell lines compared to zingerone. Moreover, the lower dose of zingerone NPs (25 µM) markedly inhibited colony formation and colony survival by at least five-fold compared to zingerone treatment. Additionally, zingerone NPs significantly attenuated cell motility and invasiveness. In terms of the signaling mechanism, we determined that the zingerone NP-mediated downregulation of Akt signaling played an important role in the inhibition of cell viability and cell motility. Zingerone NPs inhibited matrix metalloproteinase (MMP) activity, which was highly correlated with the attenuation of cell migration and cell invasion. By further detecting the roles of zingerone NPs in epithelial–mesenchymal transition (EMT), we observed that zingerone NPs substantially altered the levels of EMT-related markers by decreasing the levels of the mesenchymal markers, N-cadherin and vimentin, rather than the epithelial proteins, ZO-1 and E-cadherin, compared with zingerone. In conclusion, as novel and efficient phytochemically derived nanoparticles, zingerone NPs may serve as a potent adjuvant to protect against cell invasion and metastasis, which will provide a beneficial strategy for future applications in chemoprevention and conventional therapeutics in OSCC treatment.

Platelet CLEC2-Podoplanin Axis as a Promising Target for Oral Cancer Treatment

Cancer tissues are not just simple masses of malignant cells, but rather complex and heterogeneous collections of cellular and even non-cellular components, such as endothelial cells, stromal cells, immune cells, and collagens, referred to as tumor microenvironment (TME). These multiple players in the TME develop dynamic interactions with each other, which determines the characteristics of the tumor. Platelets are the smallest cells in the bloodstream and primarily regulate blood coagulation and hemostasis. Notably, cancer patients often show thrombocytosis, a status of an increased platelet number in the bloodstream, as well as the platelet infiltration into the tumor stroma, which contributes to cancer promotion and progression. Thus, platelets function as one of the important stromal components in the TME, emerging as a promising chemotherapeutic target. However, the use of traditional antiplatelet agents, such as aspirin, has limitations mainly due to increased bleeding complications. This requires to implement new strategies to target platelets for anti-cancer effects. In oral squamous cell carcinoma (OSCC) patients, both high platelet counts and low tumor-stromal ratio (high stroma) are strongly correlated with increased metastasis and poor prognosis. OSCC tends to invade adjacent tissues and bones and spread to the lymph nodes for distant metastasis, which is a huge hurdle for OSCC treatment in spite of relatively easy access for visual examination of precancerous lesions in the oral cavity. Therefore, locoregional control of the primary tumor is crucial for OSCC treatment. Similar to thrombocytosis, higher expression of podoplanin (PDPN) has been suggested as a predictive marker for higher frequency of lymph node metastasis of OSCC. Cumulative evidence supports that platelets can directly interact with PDPN-expressing cancer cells via C-type lectin-like receptor 2 (CLEC2), contributing to cancer cell invasion and metastasis. Thus, the platelet CLEC2-PDPN axis could be a pinpoint target to inhibit interaction between platelets and OSCC, avoiding undesirable side effects. Here, we will review the role of platelets in cancer, particularly focusing on CLEC2-PDPN interaction, and will assess their potentials as therapeutic targets for OSCC treatment.

EPHB4 Regulates the Proliferation and Metastasis of Oral Squamous Cell Carcinoma through the HMGB1/NF-κB Signalling Pathway

Background: Malignant proliferation and cervical lymphatic metastasis restrict the prognosis of oral squamous cell carcinoma (OSCC). Erythropoietin-producing human hepatocellular B4 (EPHB4) regulates a series of tumour functions involving tumourigenesis, cancer cell attachment and metastasis. However, the mechanism of EphB4 regulating the malignant progression of OSCC has not been fully elucidated. Methods: EPHB4 expression was analysed in 65 OSCC samples and adjacent noncancerous tissues through immunohistochemistry (IHC). siRNA and overexpression plasmids were transfected into OSCC cells to modify EPHB4 expression, and then, regulatory functions were explored in vitro and in vivo. Co-immunoprecipitation (Co-IP) and mass spectrometry were applied to detect proteins interacting with EPHB4. Subsequently, protein stability assays and NF-κB pathway inhibition assays were used to verify the regulation of EPHB4, high-mobility group box 1 (HMGB1) and nuclear factor-κB (NF-κB) activation. Results: EPHB4 was found to be highly expressed in OSCC tissues, which was related to tumour stage and lymphatic metastasis and resulted in a poor prognosis. Cellular experiments and mouse tongue xenograft models further confirmed that high EPHB4 expression promoted the proliferation and metastasis of OSCC tumours. Mechanistically, co-IP and mass spectrometry studies indicated that EPHB4 could bind to HMGB1 and maintain HMGB1 stability. Downregulation of HMGB1 inhibited the proliferation and metastasis of OSCC cells and inhibited NF-κB phosphorylation activation but did not affect EPHB4 expression. Conclusion: This study revealed the mechanism by which EPHB4 promotes the proliferation and metastasis of OSCC by activating the HMGB1-mediated NF-κB signalling pathway, which can be exploited as a novel marker or therapeutic target to control metastasis and improve the survival rate of OSCC.

LncRNA MIR31HG Drives Oncogenicity by Inhibiting the Limb-Bud and Heart Development Gene (LBH) during Oral Carcinoma

The miR-31 host gene (MIR31HG) encodes a long non-coding RNA (LncRNA) that harbors miR-31 in its intron 2; miR-31 promotes malignant neoplastic progression. Overexpression of MIR31HG and of miR-31 occurs during oral squamous cell carcinoma (OSCC). However, the downstream effectors modulated by MIR31HG during OSCC pathogenesis remain unclear. The present study identifies up-regulation of MIR31HG expression during the potentially premalignant disorder stage of oral carcinogenesis. The potential of MIR31HG to enhance oncogenicity and to activate Wnt and FAK was identified when there was exogenous MIR31HG expression in OSCC cells. Furthermore, OSCC cell subclones with MIR31HG deleted were established using a Crispr/Cas9 strategy. RNA sequencing data obtained from cells expressing MIR31HG, cells with MIR31HG deleted and cells with miR-31 deleted identified 17 candidate genes that seem to be modulated by MIR31HG in OSCC cells. A TCGA database algorithm pinpointed MMP1, BMP2 and Limb-Bud and Heart development (LBH) as effector genes controlled by MIR31HG during OSCC. Exogenous LBH expression decreases tumor cell invasiveness, while knockdown of LBH reverses the oncogenic suppression present in MIR31HG deletion subclones. The study provides novel insights demonstrating the contribution of the MIR31HG-LBH cascade to oral carcinogenesis.

Ubiquitin D Promotes Progression of Oral Squamous Cell Carcinoma via NF-Kappa B Signaling

Ubiquitin D (UBD) is highly upregulated in many cancers, and plays a pivotal role in the pathophysiological processes of cancers. However, its roles and underlying mechanisms in oral squamous cell carcinoma (OSCC) are still unclear. In the present study, we investigated the role of UBD in patients with OSCC. Quantitative real-time polymerase chain reaction and Western blot were used to measure the expression of UBD in OSCC tissues. Immunohistochemistry assay was used to detect the differential expressions of UBD in 244 OSCC patients and 32 cases of normal oral mucosae. In addition, CCK-8, colony formation, wound healing and Transwell assays were performed to evaluate the effect of UBD on the cell proliferation, migration, and invasion in OSCC. Furthermore, a xenograft tumor model was established to verify the role of UBD on tumor formation in vivo. We found that UBD was upregulated in human OSCC tissues and cell lines and was associated with clinical and pathological features of patients. Moreover, the overexpression of UBD promoted the proliferation, migration and invasion of OSCC cells; however, the knockdown of UBD exerted the opposite effects. In this study, our results also suggested that UBD promoted OSCC progression through NF-κB signaling. Our findings indicated that UBD played a critical role in OSCC and may serve as a prognostic biomarker and potential therapeutic target for OSCC treatment.

Paradoxical Roles of Desmosomal Components in Head and Neck Cancer

Desmosomes are intercellular adhesion complexes involved in various aspects of epithelial pathophysiology, including tissue homeostasis, morphogenesis, and disease development. Recent studies have reported that the abnormal expression of various desmosomal components correlates with tumor progression and poor survival. In addition, desmosomes have been shown to act as a signaling platform to regulate the proliferation, invasion, migration, morphogenesis, and apoptosis of cancer cells. The occurrence and progression of head and neck cancer (HNC) is accompanied by abnormal expression of desmosomal components and loss of desmosome structure. However, the role of desmosomal components in the progression of HNC remains controversial. This review aims to provide an overview of recent developments showing the paradoxical roles of desmosomal components in tumor suppression and promotion. It offers valuable insights for HNC diagnosis and therapeutics development.

An integrated approach for identification of a panel of candidate genes arbitrated for invasion and metastasis in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is known for its aggressiveness associated with poor prognosis. The molecular mechanisms underlying the invasion and metastasis are still poorly understood. An improved understanding of these mechanisms shall precede the development of new diagnostic tools and targeted therapies. We report an integrated approach using bioinformatics to predict candidate genes, coupled with proteomics and immunohistochemistry for validating their presence and involvement in OSCC pathways heralding invasion and metastasis. Four genes POSTN, TNC, CAV1 and FSCN1 were identified. A protein–protein interaction network analysis teamed with pathway analysis led us to propose the role of the identified genes in invasion and metastasis in OSCC. Further analyses of archived FFPE blocks of various grades of oral cancer was carried out using TMT-based mass spectrometry and immunohistochemistry. Results of this study expressed a strong communiqué and interrelationship between these candidate genes. This study emphasizes the significance of a molecular biomarker panel as a diagnostic tool and its correlation with the invasion and metastatic pathway of OSCC. An insight into the probable association of CAF's and these biomarkers in the evolution and malignant transformation of OSCC further magnifies the molecular-biological spectrum of OSCC tumour microenvironment.

Relationship Between mir15b and Sal-Like Protein 4 and Biological Behavior of Oral Squamous Cell Carcinoma

miR15b and SALL4 are involved in a variety of tumor progression. The roles of miR15b and SALL4 in oral squamous cell carcinoma (OSCC) remains unclear. The tumors and normal mucosa of OSCC patients were collected to detect miR15b and SALL4 level by Real-time PCR and analyze their correlation with OSCC clinicopathological features. Oral cancer Tca8113 cells were separated into control group; miR15b mimics group and miR15b inhibitor group followed by analysis of SALL4 expression, cell survival by MTT assay; cell invasion by Transwell chamber assay, as well as expression of N-cadherin and Vimentin and correlated with TNM stage, tumor volume and metastasis, and positively with differentiation TGF-β by Western blot. miR15b expression was decreased and SALL4 expression was increased in OSCC tumor tissues. miR15b was negatively degree (P < 0.05), whereas, opposite correlation of SALL4 with the above parameters was found (P < 0.05). miR15b and SALL4 were negatively correlated. MiR15b mimics significantly up-regulated MiR15b, decreased SALL4 expression, inhibited Tca8113 cell proliferation and invasion, as well as reduced N-cadherin, Vimentin and TGF-βexpression (P < 0.05). Opposite results were found in MiR15b inhibitor group. MiR15b expression is decreased and SALL 4 is increased in OSCC tumor tissues. MiR15b and SALL4 is closely related to OSCC clinicopathological features. MiR15b regulates the expression of EMT-related genes and TGF-β, thereby altering the proliferation and invasion of OSCC cells.

Detecting cancer metastasis and accompanying protein biomarkers at single cell levels using a 3D-printed microfluidic immunoarray

A low-cost microfluidic microarray capable of lysing cells and quantifying proteins released after lysis was designed and 3D-printed. The array lyses cells on-chip in lysis buffer augmented with a 2s pulse of a sonic cell disruptor. Detection of desmoglein 3 (DSG3), a metastatic biomarker for head and neck squamous cell carcinoma (HNSCC), along with two accompanying HNSCC biomarkers from a single cell lysate of oral cancer cell cultures was demonstrated. A lysis chamber and reagent compartments deliver sample and reagents into detection chambers decorated with capture antibodies immobilized onto inner walls coated with a highly swollen 3D chitosan hydrogel film. Sandwich immunoassays are achieved when captured analytes labeled with biotinylated secondary antibodies, which then capture streptavidin-poly [horse radish peroxidase] (Poly-HRP). Subsequent delivery of super-bright femto-luminol with H2O2 generates chemiluminescence captured with a CCD camera. DSG3 is membrane-bound protein in HNSCC cells of invaded lymph nodes, vascular endothelial growth factor-A (VEGF-A), vascular endothelial growth factor-C (VEGF-C) were positive controls overexpressed into the HNSCC culture medium. Beta-tubulin (β-Tub) was used as a loading control to estimate the number of cells in analyzed samples. Limits of detection (LOD) were 0.10 fg/mL for DSG3, and 0.20 fg/mL for VEGF-A, VEGF-C and β-Tub. Three orders of magnitude semilogarithmic dynamic ranges were achieved. VEGF-A showed high in-cell expression, but VEGF-C had low levels inside cells. The very low LODs enabled quantifying these proteins released from single cells. Strong correlation between results from on-chip cell lysis, conventional off-line lysis and ELISA confirmed accuracy.

SNHG3/miR-2682-5p/HOXB8 promotes cell proliferation and migration in oral squamous cell carcinoma

OBJECTIVE

The potential molecular mechanism underlying the disease progression of oral squamous cell carcinoma (OSCC) remains largely elusive. The purpose of the study is to figure out the role and molecular mechanism of homeobox B8 (HOXB8) in OSCC.

MATERIALS AND METHODS

The expression level of HOXB8 in OSCC was validated by RT-qPCR. The functions of HOXB8 in OSCC cells were identified through loss-of-function assays, including CCK-8 assay, colony formation assay, transwell assay, and immunofluorescence (IF). The upstream miRNA that could directly target HOXB8 was searched out through bioinformatics analysis and luciferase reporter assay. Mechanism experiments were further conducted to predict the long non-coding RNA (lncRNA) that could positively regulate HOXB8 and compete for miR-2682-5p with HOXB8.

RESULTS

HOXB8 was markedly upregulated in OSCC tissues and cell lines. Furthermore, cell proliferation and migration were inhibited due to the shortage of HOXB8. HOXB8 was targeted by miR-2682-5p that negatively regulated cell proliferation and migration. Small nucleolar RNA host gene 3 (SNHG3) acted as a sponge for miR-2682-5p. Inhibition of miR-2682-5p or the overexpression of HOXB8 rescued the effects of SNHG3 silencing on the proliferation and migration.

CONCLUSION

HOXB8 is regulated by SNHG3/miR-2682-5p axis to promote OSCC cell proliferation and migration.

ASC modulates HIF-1α stability and induces cell mobility in OSCC

High-level expression of ASC (Apoptosis-associated speck-like protein containing a CARD) leads to lymph node metastasis in OSCC, but the underlying mechanism remains unclear. Here, we show that HIF-1α participates in ASC-induced metastasis. We identified 195 cell-motion-associated genes that were highly activated in ASC-overexpressed SAS_ASC cells; of them, 14 representative genes were found to be overexpressed in OSCC tissues in our previously reported RNA-seq dataset, OSCC-Taiwan. Nine of the 14 genes were also upregulated in OSCC-TCGA samples. Among the nine genes, RRAS2, PDGFA, and VEGFA, were correlated with poor overall survival of patients in OSCC-TCGA dataset. We further demonstrated that the promoters of these 14 ASC-induced genes contained binding motifs for the transcription-regulating factor, HIF-1α. We observed that ASC interacted with and stabilized HIF-1α in both the cytoplasm and the nucleus under normoxia. Molecules involved in the HIF-1α pathway, such as VHL and PHD2, showed no difference in their gene and protein levels in the presence or absence of ASC, but the expression of HIF-1α-OH, and the ubiquitination of HIF-1α were both decreased in SAS_ASC cells versus SAS_con cells. The migration and invasion activities of SAS_ASC cells were reduced when cells were treated with the HIF-1α synthesis inhibitor, digoxin. Taken together, our results demonstrate that the novel ASC-HIF-1α regulatory pathway contributes to lymph node metastasis in OSCC, potentially suggesting a new treatment strategy for OSCC.

Interleukin-22 promotes the migration and invasion of oral squamous cell carcinoma cells

The roles of interleukin-22 (IL-22) in carcinogenesis have been proposed in various neoplasms. Increased expression of IL-22 has been observed in oral squamous cell carcinoma (OSCC) lesions as well as in other cancers. OSCC is still associated with poor prognosis and a high mortality rate because of its invasiveness and frequent lymph node metastasis. In the present study, we investigated the effects of IL-22 on OSCC cells. The human OSCC cell lines Ca9-22 and SAS were stimulated with IL-22 (1-10 ng/mL), and their migration abilities were examined using a cell scratch assay. A Matrigel invasion assay was performed to evaluate the invasion abilities of OSCC cells. Signal transducer and activator of transcription 3 (STAT3) phosphorylation, matrix metalloproteinase (MMP) and epithelial-mesenchymal transition (EMT)-related genes and proteins were also examined. IL-22 treatment promoted the migration and invasion abilities of OSCC cells without increasing their viability. IL-22 stimulation also induced STAT3 phosphorylation, MMP-9 activity and EMT-related genes and proteins. Our findings suggest that IL-22 has possible roles in the development of OSCC.

Oral Potentially Malignant Disorders and Oral Cavity Cancer

The Surveillance, Epidemiology, and End Results program from the National Cancer Institute reports that the aggregate number of oral cavity and pharyngeal cancer cases has been increasing over the past decade and, despite an overall decline in oral cavity cancers, this increase is largely related to a dramatic increase in cancers involving oropharyngeal subsites. Early detection of oral cavity cancers is commensurate with improved survival, and opportunistic screening by trained clinicians to detect oral cavity cancer and oral potentially malignant disorders is recommended by the American Dental Association and the American Academy of Oral Medicine.

Distribution pattern of invasion-related bio-markers in head Marjolin's ulcer

Marjolin's ulcer (MU) is a rare and aggressive cutaneous malignancy that typically presented in an area of traumatized or chronically inflamed skin and particularly in burn scars. Among them, the MU in the scalp with extensive invasion of the skull is exceptional and severe. The principle of management for MU is to obtain an early diagnosis and perform prompt surgical interventions. The invasive capacity of MU may vary among different sites of the scalp, which may require different therapeutic strategies for surgical excision. However, no clear evidence has been provided to determine the invasion ability of MU at different regions of the lesion as a surgical guidance. In present study, a 41-year-old female with a 40-year history of scalp ulceration has been examined. After resection of the MU lesion, hematoxylin and eosin (H&E) staining was performed to confirm the pathology of the cutaneous malignancy after surgical excision. Furthermore, reverse transcription-quantitative PCR experiment was performed out to determine the expression levels of invasion-associated biomarkers at different sites of the scalp affected by MU. Pathological analysis with H&E staining indicated a differentiated squamous cell carcinoma with invasion of the skull. The invasion-associated biomarkers were highly expressed in the core region compared to the middle region as well as the edge of MU tissue. Taken together, the present study suggests that the expression pattern of invasion-associated biomarkers varies between different regions of the MU lesion. High expression levels in the core region of MU indicates that the resection of the center area may be critical for the successful surgical treatment of MU.

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.

Chrysophanol Regulates Cell Death, Metastasis, and Reactive Oxygen Species Production in Oral Cancer Cell Lines

Background

Oral cancer belongs to the class of head and neck cancers and can be life threatening if not diagnosed and treated early. Activation of cell death via apoptosis or reactive oxygen species (ROS) accumulation and inhibition of cell cycle progression, migration, and epithelial-to-mesenchymal transition (EMT) may be a good strategy to arrest the development of oral cancer. In this study, we analyzed the possible action of chrysophanol isolated from the rhizomes of Rheum palmatum on the oral cancer cell lines FaDu (human pharynx squamous cell carcinoma) and SAS (human tongue squamous carcinoma) by investigating whether chrysophanol could influence cell death.

Method

Cell viability was measured by using the MTT assay. For the detection of apoptosis, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining and subG1 population analysis were used. We also examined cell cycle progression and ROS levels by flow cytometry. Additionally, the expression of p53, p21, procaspase 3, cyclin D1, CDK4, cdc2, CDK2, E-cadherin, vimentin, and PCNA was evaluated by western blotting.

Conclusion

Chrysophanol has an anticancer effect on FaDu and SAS cell lines. There is an increase in subG1 accumulation, ROS production, and cell cycle G1 arrest after treatment with chrysophanol. On the other hand, chrysophanol inhibited cell migration/metastasis and EMT. We proposed that chrysophanol may be a good candidate compound on oral cancer treatment in the further.

Aberrant Expression of miR-103, miR-184, miR-378, miR-497 and miR-506 in Tumor Tissue from Patients with Oral Squamous Cell Carcinoma Regulates the Clinical Picture of the Patients

BACKGROUND

This study aimed to evaluate the expression patterns of miR-103, miR-184, miR-378, miR497 and in squamous cell carcinoma (SCC) of the tongue and to be compared with normal peripheral tissues.

METHODS

Tumor and marginal tissues were obtained from 50 patients with OSCC. After RNA extraction, expression level of miR-103, miR-184, miR-378, miR497, and miR506 was estimated using SYBR green master mix and real-time quantitative PCR.

RESULTS

It was observed that, there was no detectable difference in expression level of miR-103 between tumoral and marginal tissues. However, expression level of miR-184, and miR-378 showed significant increase in tumor tissue samples compared to marginal tissue samples. MiR-497 and miR-506 demonstrated considerable decrease in tumoral cells in comparison with peripheral tissues. Moreover, the expression level of miRNAs was associated with clinicopathological features of the patients.

CONCLUSIONS

Our data indicated that miR-184, miR-378, miR-497, and miR-506 can be used as a potential diagnostic and prognostic biomarker in OSCC. Nevertheless, more studies are needed to confirm this claim.
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The antilymphatic metastatic effect of hyaluronic acid in a mouse model of oral squamous cell carcinoma

Objectives: Lymphatic metastasis is the main cause of low patient survival in cases of oral squamous cell carcinoma (OSCC). Several animal models have been established to uncover the mechanism that regulates lymph node metastasis of OSCC cells. Unfortunately, these models often take a long time to establish. The prolonged tumor burden can lead to animal cachexia, which may ultimately affect the experimental outcome. To overcome the disadvantages of these models, we established an orthotopic metastatic animal model of OSCC that showed quick lymph node metastasis potential.Results: DiR dye-labeled CAL27 cells were injected into tongue tissues of BALB/c nude mice, and the cells metastasized to lymph nodes on day 3. Metastasis was monitored using an in vivo imaging system and confirmed by histological observation. Using this model, we investigated the role of hyaluronic acid (HA) on the cervical metastasis of OSCC cells. Surprisingly, we found that the presence of HA significantly reduced the incidence of metastasis to cervical lymph nodes compared with the control group. Further analysis revealed that the presence of exogenous HA promoted mesenchymal-epithelial transition (MET) in primary tumors while reducing the metastatic potential of OSCC.Conclusion: Our findings confirmed the establishment of a fast and reliable lymphatic metastatic mouse model of OSCC that can be used for investigating metastatic mechanisms and analyzing various antimetastasis strategies. An equally important discovery is the antimetastatic property of HA, which could provide a potential therapeutic strategy for OSCC.

Tumor markers in oral cancer: A review

Tumor markers are the substances produced in response to the presence of cancer either by the body itself or by the cancer cells. These markers mostly are the proteins that are produced at a greater rate by the cancer cells. Increased levels of these substances can be detected in urine, blood, or body tissues of the patients with certain types of cancer. These markers are useful in differentiating primary or secondary tumors. In few noncancerous conditions, these markers are often found to be elevated. For these reasons, the knowledge regarding these biomarkers has increased tremendously. This article classifies the different types of tumor markers and implicates their role in some diseases.

Effect of silencing of mediator of DNA damage checkpoint protein 1 on the growth of oral squamous cell carcinoma in vitro and in vivo

Mediator of DNA damage checkpoint protein 1 (MDC1) is involved in DNA damage repair and has been linked to tumor invasion, metastasis, and prognosis. This study investigated the effects of MDC1 in oral squamous cell carcinoma (OSCC) in vitro and in vivo. RNA interference-mediated knockdown of MDC1 was performed in two OSCC cell lines (Tca-8113 and KB). Real-time PCR and western blotting were performed to determine expression of mRNA and protein, respectively, of MDC1. Cell viability was assessed using the MTT assay. Colony-formation assays were performed by staining with 0.5% crystal violet. Cell migration and invasion were detected by Transwell assays. The role of MDC1 in OSCC was examined in vivo via injection of Tca-8113 cells transfected with MDC1 small interfering (si)RNA or negative-control siRNA into a mouse xenograft model of OSCC. Our results showed that MDC1 knockdown decreased cell proliferation. Inhibition of MDC1 decreased colony formation of Tca-8113 and KB cells by 62% and 68%, respectively, and MDC1 knockdown reduced the number of migratory and invasive cells compared with the control group. Moreover, the xenograft mouse model of MDC1 knockdown showed reduced tumor growth. Our study suggests that MDC1 plays a role in tumorigenesis and might be a potential target for the treatment of patients with OSCC.

Licochalcone A inhibits cell proliferation, migration, and invasion through regulating the PI3K/AKT signaling pathway in oral squamous cell carcinoma

Background: Oral squamous cell carcinoma (OSCC) is one of the most common cancers, with high metastasis and mortality. Licochalcone A (LCA) is a chalconoid from the root of Glycyrrhiza inflata, which has anti-tumor, anti-inflammatory, anti-angiogenesis effects in many cancers. However, the mechanism that underlies LCA regulating cell proliferation, migration, and invasion in OSCC remains poorly understood.

Methods: LY294002 or insulin-like growth factor 1 (IGF-1) were used to block or stimulate the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT) pathway in OSCC cells. Cell proliferation was investigated by MTT assay and proliferating cell nuclear antigen (PCNA) protein level using Western blot. The expression of metastasis-related protein was detected via Western blot. Cell migration and invasion abilities were evaluated by trans-well assay. A murine xenograft model of OSCC was established to investigate the anti-tumor effect of LCA in vivo.

Results: Treatment of LCA inhibited cell proliferation in SCC4 and CAL-27 cells. Moreover, PI3K/AKT signaling was blocked by LY294002, and activated by IGF-1. LCA could suppress proliferation, migration, and invasion of OSCC cells, which was similar to the treatment of LY294002. In addition, LCA decreased IGF-1-induced OSCC progression. In a murine xenograft model, LCA treatment protected against tumor growth and metastasis in vivo.

Conclusions: LCA might inhibit cell proliferation, migration, and invasion through regulating the PI3K/AKT pathway in OSCC, developing a potential chemotherapeutic agent for OSCC.

Differential MicroRNA Expression of miR-21 and miR-155 within Oral Cancer Extracellular Vesicles in Response to Melatonin

Objective: Extracellular vesicles derived from oral cancer cells, which include Exosomes and Oncosomes, are membranous vesicles secreted into the surrounding extracellular environment. These extracellular vesicles can regulate and modulate oral squamous cell carcinoma (OSCC) progression through the horizontal transfer of bioactive molecules including proteins, lipids and microRNA (miRNA). The primary objective of this study was to examine the potential to isolate and evaluate extracellular vesicles (including exosomes) from various oral cancer cell lines and to explore potential differences in miRNA content. Methods: The OSCC cell lines SCC9, SCC25 and CAL27 were cultured in DMEM containing 10% exosome-free fetal bovine serum. Cell-culture conditioned media was collected for exosome and extracellular vesicle isolation after 72 h. Isolation was completed using the Total Exosome Isolation reagent (Invitrogen) and extracellular vesicle RNA was purified using the Total Exosome RNA isolation kit (Invitrogen). Extracellular vesicle miRNA content was evaluated using primers specific for miR-16, -21, -133a and -155. Results: Extracellular vesicles were successfully isolated from all three OSCC cell lines and total extracellular vesicle RNA was isolated. Molecular screening using primers specific for several miRNA revealed differential baseline expression among the different cell lines. The addition of melatonin significantly reduced the expression of miR-155 in all of the OSCC extracellular vesicles. However, miR-21 was significantly increased in each of the three OSCC isolates. No significant changes in miR-133a expression were observed under melatonin administration. Conclusions: Although many studies have documented changes in gene expression among various cancers under melatonin administration, few studies have evaluated these effects on microRNAs. These results may be among the first to evaluate the effects of melatonin on microRNA expression in oral cancers, which suggests the differential modulation of specific microRNAs, such as miR-21, miR-133a and miR-155, may be of significant importance when evaluating the mechanisms and pathways involved in melatonin-associated anti-tumor effects.

Molecular Biomarkers Related to Oral Carcinoma: Clinical Trial Outcome Evaluation in a Literature Review

Backgrounds

The objective of the present research was to systematically revise the international literature about the genetic biomarkers related to oral cancer (OC) evaluating the recent findings in clinical studies.

Methods

A comprehensive review of the current literature was conducted according to the PRISMA guidelines by accessing the NCBI PubMed database. The authors conducted the search of articles in the English language published from 2008 to 2018. The present systematic review included only papers with significant results about correlation between wound healing, genetic alteration, and OC. Prognostic capacity of genetic markers was not evaluated in vivo.

Results

The first analysis with filters recorded about 1884 published papers. Beyond reading and consideration of suitability, only 20 and then 8 papers, with case report exclusion, were recorded for the revision.

Conclusion

All the researches recorded the proteomic and genetic alterations in OC human biopsy cells. The gene modification level in the different studies, compared with samples of healthy tissues, has always been statistically significant, but it is not possible to associate publications with each other because each job is based on the measurement of different biomarkers and gene targets. Further investigations should be required in order to state scientific evidence about a clear advantage of using these biomarkers for diagnostic purpose.

MiR-495/IGF-1/AKT Signaling as a Novel Axis Is Involved in the Epithelial-to-Mesenchymal Transition of Oral Squamous Cell Carcinoma

PURPOSE

Increasing evidence suggests that aberrant expression of miR-495 is associated with the progression of various cancers. The aim of this study was to investigate the function and underlying mechanism of miR-495 in oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

OSCC specimens and oral cancer cell lines, as well as the OSCC microRNA expression profile from the Gene Expression Omnibus database, were used to detect the expression of miR-495 in OSCC. Cell proliferation, migration, and invasion assays were performed to analyze the function of miR-495. Bioinformatics and luciferase reporter assays were used to identify the target gene of miR-495. Pearson analysis was carried out to investigate the correlation between miR-495 and insulin-like growth factor 1 (IGF1) or AKT levels. Transfection of pcDNA3.1 vector and small interfering RNA was performed to overexpress or downregulate the expression of IGF1. OSCC xenografts in mice were constructed to validate the function and mechanism of miR-495 in vivo.

RESULTS

MiR-495 was downregulated in OSCC tissues and cell lines, and it markedly inhibited cell proliferation, migration, and invasion, as well as epithelial-to-mesenchymal transition (EMT)-related proteins of OSCC cells. IGF1 was identified as a direct target gene of miR-495. Besides, AKT was confirmed to be regulated by miR-495/IGF-1 signaling, and miR-495 was negatively correlated with IGF1 and AKT in OSCC. In vivo, miR-495 inhibited the growth and EMT-related proteins of OSCC xenografts in mice.

CONCLUSIONS

The miR-495/IGF-1/AKT signaling axis played a tumor-suppressive role in OSCC by regulating cell proliferation, invasion, and migration, as well as EMT.

Targeting ROR1 inhibits epithelial to mesenchymal transition in human lung adenocarcinoma via mTOR signaling pathway

The receptor tyrosine kinase-like orphan receptor 1 (ROR1) is a type I surface transmembrane protein that contributes to progression of tumor-cell growth and metastasis. We and others have shown that the roles of ROR1 include inhibiting apoptosis, potentiating EGFR signaling, and inducing proliferation in lung cancer, but the roles and mechanisms of ROR1 in lung adenocarcinoma metastasis have not been elucidated. Here we chose four lung adenocarcinoma cell lines, PC9 (erlotinib-sensitive), PC9erlo (acquired erlotinib-resistant), NCI-H358 (partial erlotinib-resistant), and NCI-H1975 (erlotinib-resistant) as cell models to simulate the clinical situation. We found that ROR1 prompted epithelial to mesenchymal transition (EMT) by increasing the expression level of a key epithelial gene, E-cadherin, while decreasing the expression level of the key mesenchymal gene vimentin. Silencing ROR1 by siRNA significantly reduced the migration and invasion of lung adenocarcinoma cells in vitro and also significantly inhibited the phosphorylation of Akt (Ser473), mTOR (Ser2448), Raptor (Ser792) and p70S6K (Thr389) in all four cell lines. This strongly supports our proposal that ROR1 may play a central role in tumor progression and metastasis in lung adenocarcinoma through mTOR signaling, regardless of its EGFR-TKI sensitivity status.