Molecular pathways of oral cancer that predict prognosis and survival: A systematic review

Potential targets of diosgenin for the treatment of oral squamous cell carcinoma and their bioinformatics and transcriptional profiling analyses

Diosgenin can inhibit the proliferation and cause apoptosis of various tumor cells, and its inhibitory effect on oral squamous cell carcinoma (OSCC) and its mechanism are still unclear. In this study, we predicted the targets of diosgenin for the treatment of OSCC through the database, then performed bioinformatics analysis of the targets, and further verified the effect of diosgenin on the activity of OSCC cell line HSC-3, the transcriptional profile of the targets and the molecular docking of the targets with diosgenin. The results revealed that there were 146 potential targets of diosgenin for OSCC treatment, which involved signaling pathways such as Ras, TNF, PI3K-AKT, HIF, NF-κB, and could regulate cellular activity through apoptosis, autophagy, proliferation and differentiation, inflammatory response, DNA repair, etc. Diosgenin significantly inhibited HSC-3 cell activity. The genes such as AKT1, MET1, SRC1, APP1, CCND1, MYC, PTGS2, AR, NFKB1, BIRC2, MDM2, BCL2L1, MMP2, may be important targets of its action, not only their expression was regulated by diosgenin but also their proteins had a high binding energy with diosgenin. These results suggest that diosgenin may have a therapeutic effect on OSCC through AKT1, MMP2 and other targets and multiple signaling pathways, which is of potential clinical value.

Expression of Toll-like receptors in oral squamous cell carcinoma

Almost 380,000 new cases of oral cancer were reported worldwide in 2020. Oral squamous cell carcinoma (OSCC) accounts for 90% of all types of oral cancers. Emerging studies have shown association of Toll-like receptors (TLRs) in carcinogenesis. The present study aimed to investigate the expression levels and tissue localization of TRL1 to TRL10 and NF-κB between OSCC and healthy oral mucosa, as well as effect of Candida colonization in TRL expression in OSCC. Full thickness biopsies and microbial samples from 30 newly diagnosed primary OSCC patients and 26 health controls were collected. The expression of TLR1 to TLR10 and NF-κB was analyzed by immunohistochemistry. Microbial samples were collected from oral mucosa to detect Candida. OSCC epithelium showed lower staining intensity of TRL1, TRL2 TRL5, and TRL8 as compared to healthy controls. Similarly, staining intensity of TRL3, TRL4, TRL7, and TRL8 were significantly decreased in basement membrane (BM) zone. Likewise, OSCC endothelium showed lower staining intensity of TLR4, TLR7 and TLR8. Expression of NF-κB was significantly stronger in normal healthy tissue compared to OSCC sample. Positive correlation was found between the expression of NF-κB, TRL9 and TRL10 in basal layer of the infiltrative zone OSCC samples (P = 0.04 and P = 0.002, respectively). Significant increase in TRL4 was seen in BM zone of sample colonized with Candida (P = 0.01). According to the limited number of samples, our data indicates downregulation of TLRs and NF-κB in OSCC, and upregulation of TLR4 expression with presence of Candida.

Comprehensive analysis of the prognosis and biological significance of RORβ in head and neck squamous cell carcinoma

Recent studies have shown that abnormal expression of the core circadian clock gene, retinoic acid-related orphan receptor β (RORβ ), is closely associated with the occurrence and progression of various malignant tumors. However, the expression and function of RORβ in head and neck squamous cell carcinoma (HNSCC) remains unclear. Here, we comprehensively investigated the altered expression, clinical significance, prognostic value, and biological functions of RORβ in HNSC, as well as its correlation with changes in the tumor immune microenvironment. We found that RORβ expression was decreased in HNSC and 19 other cancers. Low RORβ expression was significantly associated with tumor size, clinical stage, and survival time in HNSC patients, indicating that it may have diagnostic and prognostic value in HNSCC. Epigenetic analysis showed that the promoter methylation level of RORβ was significantly higher in HNSCC compared to adjacent noncancerous tissues. Furthermore, RORβ hypermethylation was significantly associated with low expression levels of RORβ and poor prognosis in HNSCC patients (p < 0.05). Enrichment analysis found that RORβ was involved in immune system regulation and T-cell activation, as well as the PI3K/AKT and ECM receptors interaction pathways. In vitro assays revealed that RORβ regulated the proliferation, migration and invasion ability of HNSCC cells. Additionally, we found that RORβ expression was significantly correlated with changes in the tumor immune microenvironment, suggesting it may affect prognosis by regulating immune infiltration in HNSC patients. Therefore, RORβ may serve as a potential prognostic biomarker and therapeutic target for HNSCC patients.

Scirpusin B isolated from Passiflora edulis Var. flavicarpa attenuates carbohydrate digestive enzymes, pathogenic bacteria and oral squamous cell carcinoma

Passiflora edulis Var. flavicarpa (passion fruit) generates vast waste (60-70%) in the form of peel and seed after the juice extraction. The study aimed to isolate Scirpusin B (SB) from passion fruit (PF) seed waste collected from Northeast India and to analyse its anti-radical, antibacterial, anti-diabetic, and anti-oral cancer activities. Scirpusin B was isolated following hydro-alcoholic extraction, fractionation, and column chromatography. The isolated fraction was further identified through NMR and mass spectroscopy. SB exhibited significant antiradical activity against six standard antioxidant compounds, indicating its commercial application. SB inhibited α-amylase (IC50 Value: 76.38 ± 0.25 µg/mL) and α-glucosidase digestive enzymes (IC50 Value: 2.32 ± 0.04 µg/mL), signifying its antidiabetic properties. In addition, SB showed profound antibacterial activity against eight gram-positive and gram-negative bacteria reported for the first time. Furthermore, SB inhibited SAS and TTN oral cancer cell proliferation up to 95% and 83%, respectively. SB significantly inhibited colonies of SAS and TTn cells in the clonogenic assay, attributing to its anticancer properties. The PI-FACS assay confirmed the ability of SB (75 µM) to kill SAS and TTn cells by 40.26 and 44.3% in 72 h. The mechanism of SB inhibiting oral cancer cell proliferation was understood through western blot analysis, where SB significantly suppressed different cancer hallmark proteins, such as TNF-α, survivin, COX-2, cyclin D1, and VEGF-A. The present study suggests that SB isolated from PF seed can add noteworthy value to the waste biomass for various industrial and medical applications.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03876-6.

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 tissue markers associated with tumor microenvironment in the progression and immune suppression of oral squamous cell carcinoma

Head and neck cancers (HNC) continues to dominate major cancers contributing to  mortality worldwide. Squamous cell carcinoma is the major type of HNC. Oral Squamous Cell Carcinoma grouped under HNC is a malignant tumor occurring in the oral cavity. The primary risk factors of OSCC are tobacco, alcohol consumption, etc. This review focuses on modulations, mechanisms, growth and differentiation of oral squamous cell carcinoma. Cancer cell surrounds itself with a group of elements forming a favorable environment known as tumor microenvironment (TME). It consists of numerous cells which includes immune cells, blood cells and acellular components that are responsible for the progression, immunosuppression, metastasis and angiogenesis of cancer. This review highlights the most important tissue biomarkers (mTOR, CAF, FOXp3, CD163, CD33, CD34) that are associated with TME cells. mTOR remains as the primary regulator responsible in cancer and its importance towards immune-suppression is highlighted. Tumor-associated macrophages associated with cancer development and its relationship with immunomodulatory mechanism and Tregs, which are potential blockers of immune response and its mechanism and aberrations are discussed. Cancer-associated fibroblasts that are a part of TME and their role in evading the immune response and myeloid derived suppressor cells that have slight control over the immune response and their mechanism in the tumor progression is further explained. These markers have been emphasised as therapeutic targets and are currently in different stages of clinical trials.

Conceptual model for progression of oral cancer - our perspective

Oral cancer was and still is an underestimated disease in terms of incidence and mortality rates. As a result, requires early detection and urgent prevention. This article describes a framework that covers the significant stages of conceptual development of oral cancer. Conceptual model is useful in understanding the pathogenesis and understand the disease processes. This article signifies information on various aspects of perspective risk and the role played by it. Article covers the following aspects: what are the perspective risks, what changes it causes to normal cell, what are the direct and indirect effects on normal cell, cellular changes seen with normal cell when affected with perspective risk, transformation of normal cell to oral potentially malignant disorders (OPMD) and changes seen during transformation into cancer. Understanding the conceptual model of oral cancer transformation will be a paradigm shift in future research in the field and early management of oral cancer, which will reduce the disease burden on the nation.

Tumour microenvironment and aberrant signaling pathways in cisplatin resistance and strategies to overcome in oral cancer

OBJECTIVE

Oral cancer is the sixteenth most prevalent cancer in the world and the third-most in India. Despite of several treatment modalities, the cure rate of oral cancer is still low due to drug resistance mechanisms, which are caused by many reasons. It is necessary to improve the existing treatment strategies and discover neoteric therapy to kill cancer cells, which will give oral cancer's cure rate more success. So this review aims to delineate the molecular mechanisms behind cisplatin resistance, specifically the role of the tumor microenvironment, extracellular vesicles, and altered signaling pathways and its overcoming strategies in oral cancer.

DESIGN

This review was designed by searching words like cancer, oral cancer, cisplatin-resistance, tumor microenvironment, aberrant signalings, and extracellular vesicles, overcoming strategies for cisplatin resistance in databases like PubMed, Google Scholar, web science, and Scopus. Data available in this review is from 2017 to 2021.

RESULTS

After searching too much data, we found these 98 data appropriate for our review. From these data, we found that tumor microenvironment, extracellular vesicles, and altered signaling pathways like PI3K/AKT, EGFR, NOTCH, Ras, PTEN, Nf-κβ, and Wnt signaling have a crucial role in resistance development towards cisplatin in oral cancer.

CONCLUSIONS

Lastly, this review explores the alternative strategies to overcome cisplatin resistance likely, the combination therapy and targeted therapy by combining more than one chemotherapeutic drug or inhibitors of signaling pathways and also by using nanoparticle loaded drugs that will reduce the drug efflux, which gives new treatment strategies.

Knockdown of Stromal Interaction Molecule 1 (STIM1) Suppresses Acute Myeloblastic Leukemia-M5 Cell Line Survival Through Inhibition of Reactive Oxygen Species Activities

Objective

This study aimed to investigate the role of the stromal interaction molecule 1 (STIM1) gene in the survival of the acute myeloblastic leukemia (AML)-M5 cell line (THP-1).

Materials and Methods

The STIM1 effect was assessed via dicersubstrate siRNA-mediated STIM1 knockdown. The effect of STIM1 knockdown on the expression of AKT and MAPK pathway-related genes and reactive oxygen species (ROS) generation-related genes was tested using real-time polymerase chain reaction. Cellular functions, including ROS generation, cell proliferation, and colony formation, were also evaluated following STIM1 knockdown.

Results

The findings revealed that STIM1 knockdown reduced intracellular ROS levels via downregulation of NOX2 and PKC. These findings were associated with the downregulation of AKT, KRAS, MAPK, and CMYC. BCL2 was also downregulated, while BAX was upregulated following STIM1 knockdown. Furthermore, STIM1 knockdown reduced THP-1 cell proliferation and colony formation.

Conclusion

This study has demonstrated the role of STIM1 in promoting AML cell proliferation and survival through enhanced ROS generation and regulation of AKT/MAPK-related pathways. These findings may help establish STIM1 as a potential therapeutic target for AML treatment.

Micrometastasis detection using modified papanicolaou stain in nodal tissues of oral squamous cell carcinoma - A histological study

CONTEXT

Cervical lymph node metastasis is the most important prognostic factor in Squamous Cell Carcinoma of Head and Neck (SCCHN). Detection and evaluation of micro-metastasis forms the basis for diagnosis, staging, treatment options and prognosis. Lymph node prognostic factors are extremely important for the survival and recurrence in the patient. Assessing lymph node metastasis in the absence of clinical enlargement is challenging.

AIM

To evaluate micrometastasis and individual tumor cells (ITC) in regional lymph nodes of oral squamous cell carcinoma (OSCC) by modified papanicolaou (PAP) stain and re-evaluate the tumor staging.

SETTINGS AND DESIGN

The retrospective study was executed at MS Ramaiah University of Applied Sciences.

METHODS AND MATERIALS

The current study constituted a total of 40 lymph nodes from OSCC patients, metastatic (n=20) and non-metastatic lymph nodes (n=20). All sections were stained with H & E followed by modified PAP stain. Modified PAP was used for identification of micrometastasis deposits.

STATISTICAL ANALYSIS USED

The Chi square test was employed to analyze significance.

RESULTS

Modified PAP stain proved to be more accurate (p = 0.006) than H and E stain in detecting micrometastasis which accounted for 15% of non-metastatic lymph node sections used in our study.

CONCLUSION

Special stain like modified PAP stain is valuable and sensitive in detecting micro-metastasis over H and E stain. Detection of micrometastasis in OSCC patients is advantageous for the patient as it influences staging, it modifies the treatment plan in terms of both radiotherapy and chemotherapy.

Identifying Drug Targets of Oral Squamous Cell Carcinoma through a Systems Biology Method and Genome-Wide Microarray Data for Drug Discovery by Deep Learning and Drug Design Specifications

In this study, we provide a systems biology method to investigate the carcinogenic mechanism of oral squamous cell carcinoma (OSCC) in order to identify some important biomarkers as drug targets. Further, a systematic drug discovery method with a deep neural network (DNN)-based drug–target interaction (DTI) model and drug design specifications is proposed to design a potential multiple-molecule drug for the medical treatment of OSCC before clinical trials. First, we use big database mining to construct the candidate genome-wide genetic and epigenetic network (GWGEN) including a protein–protein interaction network (PPIN) and a gene regulatory network (GRN) for OSCC and non-OSCC. In the next step, real GWGENs are identified for OSCC and non-OSCC by system identification and system order detection methods based on the OSCC and non-OSCC microarray data, respectively. Then, the principal network projection (PNP) method was used to extract core GWGENs of OSCC and non-OSCC from real GWGENs of OSCC and non-OSCC, respectively. Afterward, core signaling pathways were constructed through the annotation of KEGG pathways, and then the carcinogenic mechanism of OSCC was investigated by comparing the core signal pathways and their downstream abnormal cellular functions of OSCC and non-OSCC. Consequently, HES1, TCF, NF-κB and SP1 are identified as significant biomarkers of OSCC. In order to discover multiple molecular drugs for these significant biomarkers (drug targets) of the carcinogenic mechanism of OSCC, we trained a DNN-based drug–target interaction (DTI) model by DTI databases to predict candidate drugs for these significant biomarkers. Finally, drug design specifications such as adequate drug regulation ability, low toxicity and high sensitivity are employed to filter out the appropriate molecular drugs metformin, gefitinib and gallic-acid to combine as a potential multiple-molecule drug for the therapeutic treatment of OSCC.

Seco-Lupane Triterpene Derivatives Induce Ferroptosis through GPX4/ACSL4 Axis and Target Cyclin D1 to Block the Cell Cycle

In this study, 70 new seco-lupane triterpene derivatives were designed, synthesized, and characterized, and their in vitro anticancer activities were evaluated. Structure-activity relationship studies showed that most compounds inhibited the growth of a variety of tumor cells in vitro. With the extension of alkyl chains, the activity of azole compounds gradually increased while that of indole compounds first increased and then decreased. Moreover, all indole derivatives showed stronger anticancer activity than azole derivatives. In addition, compound 21 showed the strongest inhibitory effect on HepG2 cells with an IC₅₀ value of 0.97 μM. Mechanistic studies showed that compound 21 coregulates the cell death process by inducing ferroptosis and regulating the cell cycle. In conclusion, compound 21 can be used as a ferroptosis inducer and cycle blocker to regulate the HepG2 death process, and it has the potential to become an effective new drug for the treatment of hepatocellular carcinoma.

BTC as a Novel Biomarker Contributing to EMT via the PI3K-AKT Pathway in OSCC

Purpose: Oral squamous cell carcinoma (OSCC) is one of the most common malignant tumors of the head and neck, while metastasis is the main cause of OSCC-related death. There is an urgent need to explore novel prognostic biomarkers and identify biological targets related to metastasis in OSCC treatment.

Methods: Analysis of differential expression was performed using datasets in The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). Immunohistochemistry (IHC) was conducted to assess the expression of betacellulin (BTC) in OSCC. SCC4 and CAL27 cells were used for in vitro experiments, in which CCK-8, transwell assays, and wounding healing assays were performed to verify the biological functions of BTC. The role of BTC in EMT was analyzed by EMT score and Western blot.

Results: Through the analysis of the mRNA expression profile data from TCGA database in OSCC, we found that only low expression of BTC was significantly correlated with a poor prognosis in OSCC patients. The results of IHC assays and TCGA databases showed that the expression level of BTC was related to the tumor stage, histological grade, and metastasis status. In vitro analysis showed that overexpression of BTC significantly suppressed the proliferation and migration of OSCC cells. Furthermore, we confirmed that BTC could affect EMT through the PI3K-AKT signaling pathway.

Conclusion: The overexpression of BTC suppresses the proliferation, migration, and EMT of OSCC cells via the PI3K-AKT pathways, leading to a better prognosis in OSCC. BTC may be used as a novel molecular marker to assess the prognosis of OSCC patients.

NFκB (RelA) mediates transactivation of hnRNPD in oral cancer cells

Heterogeneous Ribonucleoprotein D (hnRNPD) is an RNA binding protein involved in post-transcriptional regulation of multiple mediators of carcinogenesis. We previously demonstrated a strong association of hnRNPD over expression with poor outcome in Oral Squamous Cell Carcinoma (OSCC). However, hitherto the precise molecular mechanism of its overexpression in oral cancer was not clear. Therefore, in an attempt to elucidate the transcriptional regulation of hnRNPD expression, we cloned 1406 bp of 5ʹ flanking region of human hnRNPD gene along with 257 bp of its first exon upstream to promoterless luciferase reporter gene in pGL3-Basic. Transfection of the resulting construct in SCC-4 cells yielded 1271 fold higher luciferase activity over parent vector. By promoter deletion analysis, we identified a canonical TATA box containing 126 bp core promoter region that retained ~ 58% activity of the full length promoter. In silico analysis revealed the presence of four putative NFκB binding motifs in the promoter. Sequential deletion of these motifs from the full-length promoter reporter construct coupled with luciferase assays revealed an 82% decrease in promoter activity after deletion of the first (−1358/−1347) motif and 99% reduction after the deletion of second motif (−1052/−1041). In-vivo binding of NFκB (RelA) to these two motifs in SCC-4 cells was confirmed by ChIP assays. Site directed mutagenesis of even one of these two motifs completely abolished promoter activity, while mutagenesis of the remaining two motifs had marginal effect on the same. Consistent with these findings, treatment of SCC-4 cells with PDTC, a known inhibitor of NFκB dramatically reduced the levels hnRNPD mRNA and protein. Finally, the expression of hnRNPD and NFκB in clinical specimen from 37 oral cancer patients was assessed and subjected to Spearmen’s Correlation analysis which revealed a strong positive correlation between the two. Thus, results of the present study for the first time convincingly demonstrate NFκB (RelA) mediated transcriptional upregulation of hnRNPD expression in oral cancer.

Multiple approaches to oral epithelial dysplasia degree analyses: a pilot study

BACKGROUND

Oral epithelial dysplasia (OED) is the presence of cells of an abnormal type within a tissue, which may signify a stage preceding the development of cancer. Our aim was to determine the interrelation between the expression of multiple molecular markers and the histological features of oral dysplasia.

METHODS

Fifteen samples of OED (five for each severity degree) were analyzed through software assisted image cytometry nuclear morphology. p53 (wild-type and mutated form), Bax and Bcl2 expression was immunohistochemically determined, and the gene expression of MMP1, MMP2, MMP9 and hTERT was determined by RT-PCR. The mean, standard deviation, ANOVA and Fisher's Exact Test (P<0.05) were performed.

RESULTS

Our analysis indicated congruence between the software-assisted measurement of nuclear morphology and severity degree. Only five samples were positive to p53-mutated form; and Bax was more expressed than Bcl-2. hTERT expression was significantly expressed in relation to severity, and MMP1 was predominantly expressed, followed by MMP9 and MMP2.

CONCLUSIONS

Our results reinforce that software-assisted measurement is an alternative to severity degree determination. MMP1 is an important marker for severity dysplasia degree; however, the predominant expression of Bax over Bcl-2 suggests that this pro-apoptotic state could be used to minorize the progression, perhaps, as a future therapeutic target.

Liquid biopsy: Exosomal microRNAs as novel diagnostic and prognostic biomarkers in cancer

BACKGROUND

Detecting cancer at an early stage before clinical manifestation could be an effective strategy to decrease cancer mortality. Thus, identifying liquid biopsy biomarkers with high efficacy could be a promising approach for non-invasive diagnosis of cancer.

MAIN TEXT

Liquid biopsies are increasingly used as a supplement to biopsy, as it enables disease progression to be detected months before clinical and radiographic confirmation. Many bodily fluids contain exosomal microRNAs (miRNAs) which could provide a new class of biomarkers for early and minimally invasive cancer diagnosis due to the stability of miRNAs in exosomes. In this review, we mainly focused on the exosomal miRNAs (liquid biopsy) as biomarkers in the diagnosis and prognosis of various cancers.

CONCLUSION

Exosomal miRNAs can be used as diagnostic and prognosis biomarkers that provide unique insights and a more dynamic perspective of the progression and therapeutic responses in various malignancies. Therefore, the development of novel and more sensitive technologies that exploit exosomal miRNAs should be a priority for cancer management.

Role of the Tumor Microenvironment and the Influence of Epigenetics on the Tumor Microenvironment in Oral Carcinogenesis: Potential Implications

Oral cancer has become a significant problem throughout the world, particularly in countries that are still developing. Recent literature supports the contribution of components of the tumor microenvironment (TME) and the effect of epigenetic changes happening in the cells of the TME on oral cancer development and progression. In this review, we comprehensively examine the significance of TME in the development of OC along with the current understanding of the epigenetic modifications that regulate the TME and their cohesive impact on tumor traits and their potential as therapeutic targets.

Exosome-derived microRNAs in oral squamous cell carcinomas impact disease prognosis

OBJECTIVES

microRNA (miRNA) expression patterns have provided new insight as biomarkers of prognosis as well as novel therapeutic targets for several neoplasms. However, the role of exosomal miRNA in the prognosis of oral squamous cell carcinoma (OSCC) has not yet been completely clarified. Paired primary tumor and normal oral epithelial cells from OSCC patients were obtained, and the exosomal miRNA profiles between them were compared by miRNA microarray analysis. The miRNA levels in the serum exosomes of OSCC patients were verified by real-time quantitative reverse transcription PCR (qRT-PCR) analysis. Finally, the biological functions and the potential as a prognostic marker of the selected miRNA candidates were analyzed in the OSCC cells and patients, respectively.

RESULTS

Exosomal miR-155 and miR-21 were significantly upregulated, and exosomal miR-126 was dramatically downregulated in the primary OSCC cells and the serum of OSCC patients. In the analysis of oncogenic behaviors, coculture with either miR-155-rich or miR-21-rich exosomes could promote cell proliferation and invasion accompanied with downregulation of PTEN and Bcl-6 tumor suppressors. Moreover, treatment with miR-126-rich exosomes inhibited oncogenic behaviors and oncogene EGFL7 expression in OSCC cells. Finally, exosomal miR-126 was reduced in the serum of the late-staged OSCC patients, and downregulation of blood exosomal miR-126 was associated with poor survival in OSCC patients.

CONCLUSION

Exosomal miR-155 and miR-21 are oncogenic miRNAs which suppress PTEN and Bcl-6 expression, and exosomal miR-126 acts as a tumor suppressor which downregulates EGFL7 in OSCC. Furthermore, blood exosomal miRNAs may serve as biomarkers for the diagnosis and prognosis of OSCC.

Overexpression of miRNA-9 enhances galectin-3 levels in oral cavity cancers

Oral cavity cancer (OCC) is the predominant subtype of head and neck cancer (HNC) and has up to 50% mortality. Genome-wide microRNA (miR) sequencing data indicates overexpression of miR-9-5p in HNC tumours, however, the biological role of miR-9-5p in OCC is complex; it can either act as a tumour suppressor or an oncomir, regulating many target genes at the post-transcriptional level. We have investigated the overexpression of miR-9-5p in three OCC cell lines. We have evaluated its expression levels and Galectin-3 as potential biomarkers in saliva samples collected from controls and OCC patients. We found that over expression of miR-9-5p in OCC cell lines resulted in a significant reduction in cell proliferation and migration, and an increase in apoptosis, which was paralleled by an increase in Galectin-3 secretion and export of Galectin-3 protein. Our data are consistent with miR-9-5p being a modulator of Galectin-3 via the AKT/γ-catenin pathway. In addition, the positive correlation between the levels of miR-9-5p expression and secreted Galectin-3 in saliva reflects a similar relationship in vivo, and supports the utility of their integrative evaluation in OCC. Our findings indicate that both miR-9-5p and Galectin-3 are critical biomolecules in the progression of OCC.

Prognostic biomarkers and therapeutic targets in oral squamous cell carcinoma: a study based on cross-database analysis

Background

Oral squamous cell carcinoma (OSCC) is a malignant cancer, the survival rate of patients is disappointing. Therefore, it is necessary to identify the driven-genes and prognostic biomarkers in OSCC.

Methods

Four Gene Expression Omnibus (GEO) datasets were integratedly analyzed using bioinformatics approaches, including identification of differentially expressed genes (DEGs), GO and KEGG analysis, construction of protein-protein interaction (PPI) network, selection of hub genes, analysis of prognostic information and genetic alterations of hub genes. ONCOMINE, The Cancer Genome Atlas (TCGA) and Human Protein Atlas databases were used to evaluate the expression and prognostic value of hub genes. Tumor immunity was assessed to investigate the functions of hub genes. Finally, Cox regression model was performed to construct a multiple-gene prognostic signature.

Results

Totally 261 genes were found to be dysregulated. 10 genes were considered to be the hub genes. The Kaplan-Meier analysis showed that upregulated SPP1, FN1, CXCL8, BIRC5, PLAUR, and AURKA were related to poor outcomes in OSCC patients. FOXM1 and TPX2 were considered as the potential immunotherapeutic targets with future clinical significance. Moreover, we constructed a nine-gene signature (TEX101, DSG2, SCG5, ADA, BOC, SCARA5, FST, SOCS1, and STC2), which can be utilized to predict prognosis of OSCC patients effectively.

Conclusion

These findings may provide new clues for exploring the molecular mechanisms and targeted therapy in OSCC. The hub genes and risk gene signature are helpful to the personalized treatment and prognostic judgement.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41065-021-00181-1.

SPINK7 expression changes accompanied by HER2, P53 and RB1 can be relevant in predicting oral squamous cell carcinoma at a molecular level

The oral squamous cell carcinoma (OSCC), which has a high morbidity rate, affects patients worldwide. Changes in SPINK7 in precancerous lesions could promote oncogenesis. Our aim was to evaluate SPINK7 as a potential molecular biomarker which predicts OSCC stages, compared to: HER2, TP53, RB1, NFKB and CYP4B1. This study used oral biopsies from three patient groups: dysplasia (n = 33), less invasive (n = 28) and highly invasive OSCC (n = 18). The control group consisted of clinically suspicious cases later to be confirmed as normal mucosa (n = 20). Gene levels of SPINK7, P53, RB, NFKB and CYP4B1 were quantified by qPCR. SPINK7 levels were correlated with a cohort of 330 patients from the TCGA. Also, SPINK7, HER2, TP53, and RB1, were evaluated by immunohistofluorescence. One-way Kruskal–Wallis test and Dunn's post-hoc with a p < 0.05 significance was used to analyze data. In OSCC, the SPINK7 expression had down regulated while P53, RB, NFKB and CYP4B1 had up regulated (p < 0.001). SPINK7 had also diminished in TCGA patients (p = 2.10e-6). In less invasive OSCC, SPINK7 and HER2 proteins had decreased while TP53 and RB1 had increased with respect to the other groups (p < 0.05). The changes of SPINK7 accompanied by HER2, P53 and RB1 can be used to classify the molecular stage of OSCC lesions allowing a diagnosis at molecular and histopathological levels.

Mechanism of tumour microenvironment in the progression and development of oral cancer

Oral cancer has been a major problem all across the globe, majorly in the developing countries. With a growing emphasis in the field of cancer research, the contribution of the tumour microenvironment has been gaining a lot of importance in identifying the role of components other than the tumour cells that cause the development of cancer, thus changing the outlook. The review will shed light on the studies that describe the role of microenvironment, its components as well as summarize the studies related to their mechanism in the progression of oral cancer. The literature for the review was derived mainly from Google Scholar and PubMed, in particular concentrating on the most recent papers published in 2019 and 2020, by using the keywords "Cancer, Oral Cancer, Metastasis, OSCC, Tumour microenvironment, CAFs, ECM, Cytokines, Hypoxia, Therapeutics targeting the microenvironment". The study provides insight into the world of micro-environmental regulation of oral cancer, the mechanism by which they interact and how to exploit it as a potential therapeutic haven for treating the disease. The components Cancer-Associated Fibroblasts (CAFs), Tumour-associated Macrophages (TAMs), Tumour-associated neutrophils (TANs), Hypoxic environment, myeloid-derived stem cells (MDSCs) and T regulatory (Tregs) cells and underlying mechanisms that control them will be the targets of study to understand the microenvironment.

Long non‑coding RNA AFAP1‑AS1 facilitates the growth and invasiveness of oral squamous cell carcinoma by regulating the miR‑145/HOXA1 axis

Long non-coding RNA (lncRNA) actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1) has been reported to serve important roles in multiple types of cancer. However, the biological function and underlying mechanism of AFAP1-AS1 in oral squamous cell carcinoma (OSCC) remain largely unknown. The present study aimed to investigate the biological roles and clarify the potential mechanism of AFAP1-AS1 in OSCC. The expression levels of AFAP1-AS1 in OSCC tissues and cells were determined using reverse transcription-quantitative PCR. Cell proliferation, colony formation, migration and invasion were analyzed using Cell Counting Kit-8, colony formation, wound healing and Transwell invasion assays, respectively. The potential binding between AFAP1-AS1 and microRNA (miR)-145 was validated using dual luciferase reporter and RNA pull-down assays. A xenograft tumor model was established to evaluate the effect of AFAP1-AS1 in vivo. The results revealed that AFAP1-AS1 expression levels were markedly upregulated in OSCC tissues and cells. In addition, patients with OSCC with high expression levels of AFAP1-AS1 had a poor prognosis. Functionally, the knockdown of AFAP1-AS1 in OSCC cells significantly inhibited cell proliferation, migration and invasion in vitro. Similarly, in vivo AFAP1-AS1 knockdown prevented tumor growth and reduced tumor size and weight. Mechanistically, AFAP1-AS1 was discovered to regulate the expression levels of Homeobox A1 (HOXA1) by competing with miR-145. The inhibition of miR-145 partially attenuated the inhibitory effects of AFAP1-AS1 knockdown on OSCC cells. In conclusion, the findings of the present study suggested that AFAP1-AS1 may promote the progression of OSCC by regulating the miR-145/HOXA1 axis.

Autophagy-A Hidden but Important Actor on Oral Cancer Scene

The duration of denture use, oral hygiene, smoking and male sex were identified as risk factors for oral mucosal lesions. As it is well known, all the oral mucosal lesions associated with risk factors have an important degree of malignity. Chronic mechanical irritation can be another cause of oral cancer and it is produced by the constant action of a deleterious agent from the oral cavity. Autophagy represents a complex evolutionary conserved catabolic process in which cells self-digest intracellular organelles in order to regulate their normal turnover and remove the damaged ones with compromised function to further maintain homeostasis. Autophagy is modulated by mTOR kinase and indirectly by PI3K/AKT survival pathway. Due to its dual capacity to either induce cell death or promote cell survival, important evidence pointed that autophagy has a two-faced role in response to chemotherapy in cancer. In conclusion, understanding how to overcome cytoprotective autophagy and how to take advantage of autophagic cell death is critical in order to enhance the cancer cells sensitivity to particular therapeutic agents.

Antitumor Activity of the Cardiac Glycoside αlDiginoside by Modulating Mcl-1 in Human Oral Squamous Cell Carcinoma Cells

We recently isolated a cardiac glycoside (CG), αldiginoside, from an indigenous plant in Taiwan, which exhibits potent tumor-suppressive efficacy in oral squamous cell carcinoma (OSCC) cell lines (SCC2095 and SCC4, IC₅₀ < 0.2 µM; 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays). Here, we report that αldiginoside caused Sphase arrest and apoptosis, through the inhibition of a series of signaling pathways, including those mediated by cyclin E, phospho-CDC25C (p-CDC25C), and janus kinase/signal transducer and activator of transcription (JAK/STAT)3. αldiginoside induced apoptosis, as indicated by caspase activation and poly (ADP-ribose) polymerase (PARP) cleavage. Equally important, αldiginoside reduced Mcl-1 expression through protein degradation, and overexpression of Mcl-1 partially protected SCC2095 cells from αldiginoside’s cytotoxicity. Taken together, these data suggest the translational potential of αldiginoside to foster new therapeutic strategies for OSCC treatment.

Blood-based circulating microRNAs as potential biomarkers for predicting the prognosis of head and neck cancer-a systematic review

OBJECTIVE

The aim of the present study was to systematically review the role of circulating miRNAs as potential prognostic biomarkers in head and neck cancer patients.

MATERIALS AND METHODS

PubMed, EMBASE, Scopus, Web of Science, and gray literature from January 1990 up to and including September 2019 were searched. The study selection was performed by two independent reviewers according to eligibility criteria.

RESULTS

A total of 13 studies that met the eligibility criteria were included. Significant number of studies were executed majorly in China and predominant number of them were case-control in nature. A total of 22 different miRNAs were found to be concomitant with very poor prognosis in cancers of the head and neck region. Of these, eighteen miRNAs (miR-375, miR-1234, miR-103, miR-638, miR-200b-3p, miR-191-5p, miR-24-3p, miR-572, miR-483-5p, miR-20a, miR-22, miR-29a, miR-29b, mir-let-7c, miR-17, miR-374b-5p, miR-425-5p, and miR-196a) were upregulated and four miRNAs (miR-9, miR-29c, miR-223, and miR-187∗) were downregulated. The hazard ratio (HR) ranged from twofold to fivefold.

CONCLUSION

Based on the results, circulating miRNA may assist in the prediction of prognosis of head and neck cancer. Further multi-center randomized controlled clinical trials with large sample size are required to validate the results of the present review.

CLINICAL RELEVANCE

Decoding the circulating miRNA profile could aid in accurate prognostication of head and neck cancer.

CCL18-induced LINC00319 promotes proliferation and metastasis in oral squamous cell carcinoma via the miR-199a-5p/FZD4 axis

Long non-coding RNAs (lncRNAs), which may be modulated by chemokines, are key regulators in many cancers including oral squamous cell carcinoma (OSCC). An understanding of lncRNAs involved in chemokine (CC motif) ligand 18 (CCL18)-induced OSCC promotion remains elusive. The present study using lncRNA sequencing found LINC00319 to be significantly upregulated in OSCC cells subjected to rCCL18 stimulation. Furthermore, LINC00319 knockdown was found to attenuate the carcinogenic function of CCL18 in OSCC, reducing OSCC proliferation, metastasis, epithelial-mesenchymal transition (EMT), and angiogenesis. LINC00319 was demonstrated to act as a ceRNA in OSCC, which directly responded to miR-199a-5p and rescued the repression of FZD4 by miR-199a-5p. Functionally, in vitro and in vivo experiments showed that LINC00319 promoted OSCC growth and metastasis via downregulating miR-199a-5p and upregulating FZD4. In vitro rescue assays demonstrated that miR-199a-5p inhibitor or FZD4 overexpression reversed the effects of LINC00319 silencing in OSCC. Importantly, the expression of miR-199a-5p and FZD4 were found to be mediated by CCL18, and miR-199a-5p mimics inhibited the CCL18-promoting effects in oral cancer cells. Taken together, these results evidenced a mechanism of CCL18 action in OSCC mediated through the LINC00319/miR-199a-5p/FZD4 signaling pathway, which may comprise a potential target for OSCC therapeutic development.

LINC00941 promotes oral squamous cell carcinoma progression via activating CAPRIN2 and canonical WNT/β-catenin signaling pathway

Dysregulation of long non-coding RNAs (lncRNAs) has been implicated in many cancer developments. Previous studies showed that lncRNA LINC00941 was aberrantly expressed in oral squamous cell carcinoma (OSCC). However, its role in OSCC development remains elusive. In this study, we demonstrated that in OSCC cells, EP300 activates LINC00941 transcription through up-regulating its promoter H3K27ac modification. Up-regulated LINC00941 in turn activates CAPRIN2 expression by looping to CAPRIN2 promoter. Functional assays suggest that both LINC00941 and CAPRIN2 play pivotal roles in promoting OSCC cell proliferation and colony formation. In vivo assay further confirmed the role of LINC00941 in promoting OSCC cell tumour formation. Lastly, we showed that the role of LINC00941 and CAPRIN2 in OSCC progression was mediated through activating the canonical WNT/β-catenin signaling pathway. Thus, LINC00941/CAPRIN2/ WNT/β-catenin signaling pathway provides new therapeutic targets for OSCC treatment.

Ilimaquinone Induces Apoptosis and Autophagy in Human Oral Squamous Cell Carcinoma Cells

In this study, the anti-tumor activity of ilimaquinone (IQ), a sesquiterpene quinone isolated from marine sponge Halichondria sp., in oral squamous cell carcinoma (OSCC) cells, was investigated. IQ suppressed the viability of the OSCC cell lines SCC4 and SCC2095 with IC₅₀ values of 7.5 and 8.5 μM, respectively. Flow cytometric analysis demonstrated that IQ induced caspase-dependent apoptosis in SCC4 cells and modulated the expression of several cell growth-related gene products, including Akt, p38, Mcl-1, and p53. Notably, p53 knockdown caused higher resistance to IQ’s anti-tumor activity. In addition, IQ increased reactive oxygen species generation, which was partially reversed by the addition of antioxidants. Furthermore, it triggered autophagy, as evidenced by acidic organelle formation and LC3B-II and Atg5 expression in SCC4 cells. Pretreatment with the autophagy inhibitor 3-methyladenine or chloroquine partially decreased IQ-induced apoptosis, suggesting that IQ induced protective autophagy. In summary, IQ has potential to be used in OSCC therapy.

Construction and analysis of a lncRNA-miRNA-mRNA network based on competitive endogenous RNA reveal functional lncRNAs in oral cancer

Background

A growing evidence suggests that long non-coding RNAs (lncRNAs) can function as a microRNA (miRNA) sponge in various diseases including oral cancer. However, the pathophysiological function of lncRNAs remains unclear.

Methods

Based on the competitive endogenous RNA (ceRNA) theory, we constructed a lncRNA-miRNA-mRNA network in oral cancer with the human expression profiles GSE74530 from the Gene Expression Omnibus (GEO) database. We used topological analysis to determine the hub lncRNAs in the regulatory ceRNA network. Then, function enrichment analysis was performed using the clusterProfiler R package. Clinical information was downloaded from The Cancer Genome Atlas (TCGA) database and survival analysis was performed with Kaplan-Meier analysis.

Results

A total of 238 potential co-dysregulated competing triples were obtained in the lncRNA-associated ceRNA network in oral cancer, which consisted of 10 lncRNA nodes, 41 miRNA nodes and 122 mRNA nodes. Additionally, we found lncRNA HCG22 exhibiting superior potential as a diagnostic and prognostic marker of oral cancer.

Conclusions

Our findings provide novel insights to understand the ceRNA regulation in oral cancer and identify a novel lncRNA as a potential molecular biomarker.

Targeting AKT/mTOR in Oral Cancer: Mechanisms and Advances in Clinical Trials

Oral cancer (OC) is a devastating disease that takes the lives of lots of people globally every year. The current spectrum of treatment modalities does not meet the needs of the patients. The disease heterogeneity demands personalized medicine or targeted therapies. Therefore, there is an urgent need to identify potential targets for the treatment of OC. Abundant evidence has suggested that the components of the protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) pathway are intrinsic factors for carcinogenesis. The AKT protein is central to the proliferation and survival of normal and cancer cells, and its downstream protein, mTOR, also plays an indispensable role in the cellular processes. The wide involvement of the AKT/mTOR pathway has been noted in oral squamous cell carcinoma (OSCC). This axis significantly regulates the various hallmarks of cancer, like proliferation, survival, angiogenesis, invasion, metastasis, autophagy, and epithelial-to-mesenchymal transition (EMT). Activated AKT/mTOR signaling is also associated with circadian signaling, chemoresistance and radio-resistance in OC cells. Several miRNAs, circRNAs and lncRNAs also modulate this pathway. The association of this axis with the process of tumorigenesis has culminated in the identification of its specific inhibitors for the prevention and treatment of OC. In this review, we discussed the significance of AKT/mTOR signaling in OC and its potential as a therapeutic target for the management of OC. This article also provided an update on several AKT/mTOR inhibitors that emerged as promising candidates for therapeutic interventions against OC/head and neck cancer (HNC) in clinical studies.

METTL3 Facilitates Oral Squamous Cell Carcinoma Tumorigenesis by Enhancing c-Myc Stability via YTHDF1-Mediated m6A Modification

N⁶-Methyladenosine (m⁶A) is the most common internal modification of eukaryotic messenger RNA (mRNA) that occurred on the N⁶ nitrogen of adenosine. However, the roles of m⁶A in oral squamous cell carcinoma (OSCC) are still elusive. Here, we investigate the function and mechanism of methyltransferase-like 3 (METTL3) in OSCC tumorigenesis. Clinically, METTL3 was significantly upregulated in tissue samples and correlated with the poor prognosis of OSCC patients. Functionally, loss and gain studies illustrated that METTL3 promoted the proliferation, invasion, and migration of OSCC cells in vitro, and METTL3 knockdown inhibited tumor growth in vivo. Mechanistically, methylated RNA immunoprecipitation sequencing (MeRIP-seq) illustrated that METTL3 targeted the 3′ UTR (near to stop codon) of the c-Myc transcript to install the m⁶A modification, thereby enhancing its stability. Furthermore, results revealed that YTH N⁶-methyladenosine RNA binding protein 1 (YTH domain family, member 1 [YTHDF1]) mediated the m⁶A-increased stability of c-Myc mRNA catalyzed by METTL3. In conclusion, our findings herein identify that METTL3 accelerates the c-Myc stability via YTHDF1-mediated m⁶A modification, thereby giving rise to OSCC tumorigenesis.

Prognostic Significance of ALDH1, Bmi1, and OCT4 Expression in Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma

BACKGROUND

Increasing evidence suggests the involvement of cancer stem cells (CSCs) in both oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC). Among the various CSC markers, aldehyde dehydrogenase (ALDH) 1, B cell-specific Moloney murine leukaemia virus integration site 1 (Bmi1), and octamer-binding protein 4 (OCT4) have been noted to increase in OSCC. The aim of the study was to analyze ALDH1, Bmi1, and OCT4 expression in OED and OSCC with clinicopathologic correlation and survival analysis.

METHODS

A total of 40 cases each of OED and OSCC were retrieved from departmental archives. Expression of ALDH1, Bmi1, and OCT4 was analyzed using immunohistochemistry and was correlated with clinicopathological parameters. A follow-up ranging from 6 to 52 months was considered for Kaplan-Meier survival analysis. The log-rank test was performed to analyze significant difference in survival rates.

RESULTS

The expression levels of ALDH1, Bmi1, and OCT4 increased significantly from OED through OSCC (P < .05). The expression of ALDH1 and OCT4 showed a significant correlation with lymph node metastasis. Positive cases of ALDH1 showed a significantly reduced survival rate compared to cases showing negative expression. Kaplan-Meier survival analysis showed a significant reduction of survival rate (P = .00) in patients showing a positive expression for all the 3 markers.

CONCLUSION

ALDH1 and OCT4 could be used as individual prognostic markers for assessing prognosis. ALDH1, Bmi1, and OCT4 could be used as a collective panel of markers to enable surgeons in predicting the prognosis of patients and thereby carry out prompt follow-up for such cases.

Identification of Novel MicroRNAs and Their Diagnostic and Prognostic Significance in Oral Cancer

Background: Oral cancer is one of the most prevalent cancers worldwide. Despite that the oral cavity is easily accessible for clinical examinations, oral cancers are often not promptly diagnosed. Furthermore, to date no effective biomarkers are available for oral cancer. Therefore, there is an urgent need to identify novel biomarkers able to improve both diagnostic and prognostic strategies. In this context, the development of innovative high-throughput technologies for molecular and epigenetics analyses has generated a huge amount of data that may be used for the identification of new cancer biomarkers. Methods: In the present study, GEO DataSets and TCGA miRNA profiling datasets were analyzed in order to identify miRNAs with diagnostic and prognostic significance. Furthermore, several computational approaches were adopted to establish the functional roles of these miRNAs. Results: The analysis of datasets allowed for the identification of 11 miRNAs with a potential diagnostic role for oral cancer. Additionally, eight miRNAs associated with patients' prognosis were also identified; six miRNAs predictive of patients' overall survival (OS) and one, hsa-miR-let.7i-3p, associated with tumor recurrence. Conclusion: The integrated analysis of different miRNA expression datasets allows for the identification of a set of miRNAs that, after validation, may be used for the early detection of oral cancers.