Oral cancers: Current status

Inhibin A contributes to the tumorigenesis of oral squamous cell carcinoma by KIAA1429-mediated m6A modification

BACKGROUND

Inhibin A and N6-methyladenosine methylation modifications participate in oral squamous cell carcinoma development. However, the N6-methyladenosine modification of Inhibin A in oral squamous cell carcinoma has not been revealed. This study reveals a key gene "Inhibin A" that may affect the tumorigenesis of oral squamous cell carcinoma and its molecular mechanisms on N6-methyladenosine methyltransferase KIAA1429-mediated N6-methyladenosine methylation modification.

METHODS

Bioinformatics analysis and quantitative real-time polymerase chain reaction identified the potential regulatory genes in oral squamous cell carcinoma. We examined the changes in the proliferation (Cell Counting Kit-8 assay), migration (transwell migration assay), and invasion (transwell invasion assays) of oral squamous cell carcinoma cells. We performed a xenograft tumor experiment to validate the role of Inhibin A in oral squamous cell carcinoma in vivo. The interactions between Inhibin A and KIAA1429 were analyzed using bioinformatics, methylated RNA immunoprecipitation-qPCR, quantitative real-time polymerase chain reaction, and Western blotting experiments.

RESULTS

Inhibin A had the highest expression in patients with oral squamous cell carcinoma. Inhibin A silencing impaired the ability of oral squamous cell carcinoma cells to proliferate, migrate, and invade, as well as limited the tumorous growth of oral squamous cell carcinoma cells in vivo. Bioinformatics analysis showed that Inhibin A expression positively interacted with KIAA1429 expression in The Cancer Genome Atlas database. The levels were also upregulated in our clinical samples. Furthermore, KIAA1429 silencing repressed the N6-methyladenosine level of Inhibin A in oral squamous cell carcinoma.

CONCLUSIONS

Inhibin A promotes the tumorigenesis of oral squamous cell carcinoma by KIAA1429-mediated N6-methyladenosine modification. This study adds to our current knowledge of the molecular mechanisms underlying oral squamous cell carcinoma malignancy.

Comparison of mutation landscapes of pretreatment versus recurrent squamous cell carcinoma of the oral cavity: The possible mechanism of resistance to standard treatment

BACKGROUND

A high recurrent rate of oral squamous cell carcinoma (OSCC) is a major concern in head and neck cancer treatment. The study of the genetic mutation landscape in recurrent OSCC may provide information on certain mutations associated with the pathobiology and treatment response of the OSCC.

AIM

We investigated the mutation landscape of matched pretreatment and recurrent tumors to understand the influence of genetic mutations on the pathobiology and clinical outcomes in OSCC.

METHODS AND RESULTS

We sequenced 33 formalin-fixed paraffin-embedded (FFPE) recurrent tumors, primary tumors, and primary tumors before recurrence that matched the recurrent tumors collected from Rajavithi Hospital during 2019-2021. We identified recurrent mutations from these samples by the Oncomine Ion Torrent-based next-generation sequencing on the 517 cancer-associated gene panel. From the results, we found that the most commonly mutated gene in the cohort is a histone methyltransferase KMT2D (54.55%), implicating that aberrance in epigenetic regulation may play a role in oral cancer tumorigenesis. Functional protein association network analysis of the gene frequently mutated in the recurrent tumors showed enrichment of genes that regulate the cancer cell cycle, that is, MRE11A, CDKN2A, and CYLD. This finding was confirmed in the primary-recurring matched pair. We found that recurrent tumors possess a small but recurring group of genes, with presumably the subclonal mutations driving the recurrence of the tumor, suggesting that the recurrent disease originated from a small fraction of the cancer cell that survives standard treatment. These genes were absent in the primary tumor with a good response to the standard treatment. On the other hand, we found an enrichment of DNA repair genes, namely ATR, BRCA1, BRCA2, RAD50, and MUTYH, in nonrecurrent tumors suggesting that the mutations in the DNA repair pathway may at least partially explain the different response to the standard treatment.

CONCLUSIONS

Our pilot study identified pathways of carcinogenesis in oral cancer and specific gene sets that indicate treatment responses and prognoses in this group of patients.

Steroid hormone receptor based gene delivery systems as potential oral cancer therapeutics

Glucocorticoid and Mineralocorticoid receptors are principally ligand-dependent intracellular transcription factors that are known to influence the development and growth of many human cancers. Our study investigates the potential of these receptors to act as a target for oral cancer treatment since findings in this regard are sparse till date. Leveraging the aberrant behavior of steroid hormone receptors (SHRs) in cancer, we have targeted oral cancer cells in 2D-culture using liposomes containing both synthetic as well as crude, natural SHR ligands isolated from an aqueous Indian medicinal plant. Lipoplexes thus formulated demonstrated targeted transfectability as indicated by expression of green fluorescent protein. Transfection of oral squamous cell carcinoma cells with exogenous, anticancer gene p53 lipoplexed with crude saponin-based liposome induced apoptosis of cancer cells via regulation of BAX and B-cell leukemia/lymphoma-2 (BCL2) protein levels at levels comparable with pre-established delivery systems based on synthetic SHR ligands. Our findings strongly indicate a possibility of developing plant saponin-based inexpensive delivery systems which would target cancer cells selectively with reduced risks of off target delivery and its side effects.

Esculetin unveiled: Decoding its anti-tumor potential through molecular mechanisms-A comprehensive review

BACKGROUND

The growing complexity of cancer has made it a significant concern in the medical community. Although cancer research has advanced, it is still challenging to create new effective medications due to the limitations and side effects of existing treatment strategies. These are enforcing the development of some alternative drugs from natural compounds with fewer drawbacks and side effects.

AIM

Therefore, this review aims to provide up-to-date, crucial, and all-encompassing data on esculetin's anticancer activity, including all relevant molecular and cellular processes based on in vivo and in vitro investigations.

RESULTS

According to the literature review, esculetin is available in nature and is effective against 16 different types of cancer. The general mechanism shown by esculetin is modulating signaling cascades and its related pathways, like cell proliferation, cell growth, autophagy, apoptosis, necrosis, inflammation, angiogenesis, metastasis, invasion, and DNA damage. Nanoformulation of esculetin improves this natural product's efficacy by improving water solubility. Esculetin's synergistic effects with both natural substances and conventional treatments have been shown, and this method aids in reversing resistance mechanisms by modulating resistance-related proteins. In addition, it has fewer side effects on humans than other phytochemicals and standard drugs with some good pharmacokinetic features.

CONCLUSION

Therefore, until standard chemotherapeutics are available in pharmaceutical markets, esculetin should be used as a therapeutic drug against various cancer types.

Using network pharmacological analysis and molecular docking to investigate the mechanism of action of quercetin's suppression of oral cancer

OBJECTIVE

This investigation seeks to explore the mechanism of quercetin in oral cancer by incorporating network pharmacology analysis and molecular docking.

METHODS

First, we use the network pharmacology analysis to discover possible core targets for quercetin and oral cancer. We subsequently utilized the docking of molecules techniques to calculate the affinities of critical targets and quercetin for verification.

RESULTS

TCMSP and the Swiss Target Prediction database found 190 quercetin action targets, while GeneCards, OMIM, PharmGkb, and the Therapeutic Target Database found 8971 oral cancer-related targets. Venny 2.1.0 online software conducted an intersection analysis of quercetin-related target information with information about oral cancer, and 172 putative quercetin-anti-oral cancer targets were examined. Six prospective core targets for quercetin treatment of oral cancer were identified from the PPI network topology analysis of 172 putative therapeutic targets. These targets include AKT1, PIK3R1, MYC, HIF1A, SRC, and HSP90AA1. GO enrichment function analysis showed that 2372 biological processes, 98 cell components, and 201 molecular functions were involved. Through enrichment analysis of the KEGG pathway, 172 signal pathways were obtained. A few examples are PI3K-AKT, HIF-1, IL-17, and other signaling pathways. The molecular docking scores of quercetin and the primary therapeutic targets AKT1, HIF1A, HSP90AA1, MYC, PIK3R1, and SRC are all less than -0.7 points, demonstrating good compatibility between the medicine and small molecules and suggesting that quercetin may affect oral cancer through the primary target.

CONCLUSION

This study explores quercetin's mechanism and possible targets for oral cancer treatment, offering novel approaches. Quercetin may be a multitarget medication against oral cancer in the future.

Mitochondrial DNA content as a biomarker for oral carcinogenesis: correlation with clinicopathologic parameters

BACKGROUND

Mitochondrial genome (mtDNA) exhibits greater vulnerability to mutations and/or copy number variations than nuclear counterpart (nDNA) in both normal and cancer cells due to oxidative stress generated by inflammation, viral infections, physical, mechanical, and chemical load. The study was designed to evaluate the mtDNA content in oral potentially malignant disorders (OPMDs) and oral squamous cell carcinoma (OSCC). Various parameters were analyzed including its variation with human papillomavirus (HPV) during oral carcinogenesis.

METHODS

The present cross-sectional study comprised of two hundred patients (100 OPMDs and 100 OSCCs) and 100 healthy controls. PCR amplifications were done for mtDNA content and HPV in OPMDs and OSCC using real-time and conventional PCR respectively.

RESULTS

The relative mtDNA content was assessed quantitatively and it was observed that mtDNA was greater in OSCC (7.60±0.94) followed by OPMDs (5.93±0.92) and controls (5.37±0.95). It showed a positive linear correlation with habits and increasing histopathological grades. Total HPV-positive study groups showed higher mtDNA content (7.06±1.64) than HPV-negative counterparts (6.21±1.29).

CONCLUSIONS

An elevated mutant mtDNA may be attributed to increased free radicals and selective cell clonal proliferation in test groups. Moreover, sustained HPV infection enhances tumorigenesis through mitochondria mediated apoptosis. Since, mtDNA content is directly linked to oxidative DNA damage, these quantifications might serve as a surrogate measure for invasiveness in dysplastic lesions and typify their malignant potential.

Prognostic significance of the harmonized maximum standardized uptake value of 18F-FDG-PET/CT in patients with resectable oral tongue squamous cell carcinoma: a multicenter study

OBJECTIVES

To investigate the usefulness of harmonized 18F-FDG-PET/CT parameters for predicting the postoperative recurrence and prognosis of oral tongue squamous cell carcinoma (OTSCC).

METHODS

We retrospectively analyzed the cases of 107 OTSCC patients who underwent surgical resection at four institutions in Japan in 2010-2016 and evaluated the harmonized PET parameters of the maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) for the primary tumor as the pSUVmax, pMTV, and pTLG. For lymph node metastasis, we used harmonized PET parameters of nodal-SUVmax, nodal-total MTV (tMTV), and nodal-total TLG (tTLG). The associations between the harmonized PET parameters and the patients' relapse-free survival (RFS) and overall survival (OS) were evaluated by the Kaplan-Meier method and Cox proportional hazard regression analysis for model 1 (preoperative stage) and model 2 (preoperative  +  postoperative stages).

RESULTS

The harmonized SUVmax values were significantly lower than those before harmonization (p=0.012). The pSUVmax was revealed as a significant preoperative risk factor for RFS and OS. Nodal-SUVmax, nodal-tMTV, and nodal-tTLG were significant preoperative risk factors for OS. The combination of pSUVmax + nodal-SUVmax significantly stratified the patients into a low-risk group (pSUVmax <3.97 + nodal-SUVmax <2.85 or ≥2.85) and a high-risk group (pSUVmax ≥3.97 + nodal-SUVmax <2.85 or pSUVmax ≥3.97 + nodal-SUVmax ≥2.85) for recurrence and prognosis (RFS: p=0.001; OS: p<0.001).

CONCLUSIONS

The harmonized pSUVmax is a significant prognostic factor for the survival of OTSCC patients. The combination of pSUVmax and nodal-SUVmax identified OTSCC patients at high risk for recurrence and poor prognosis at the preoperative stage.

Cytotoxic, anti-proliferative, and apoptotic evaluation of Ramalina sinensis (Ascomycota, Lecanoromycetes), lichenized fungus on oral squamous cell carcinoma cell line; in-vitro study

BACKGROUND

Scientists and medical professionals are actively striving to improve the efficacy of treatment methods for oral squamous cell carcinoma (OSCC), the most frequently occurring cancer within the oral cavity, by exploring the potential of natural products. The active pharmacological compounds found in lichenized fungi have shown potential for aiding in cancer treatment. Recent research aims to evaluate the impact of the lichenized fungus Ramalina sinensis (R. sinensis) on the cell viability and apoptosis of OSCC cell lines, considering the anti-inflammatory and anti-cancer capabilities of lichens.

METHODS

Ramalina sinensis (Ascomycota, Lecanoromycetes) was selected for investigation of its effects on a human oral squamous cell carcinoma cell line. Acetone and methanol extracts of R. sinensis on an OSCC cell line (KB cell line, NCBI Code: C152) were investigated. Viability was assessed by MTT assay analysis, and apoptotic cells were measured using flow cytometry analysis. Scratch assay was used to assess cell migration. The chemical composition and metabolic profiling of R. sinensis were investigated.

RESULTS

The growth and multiplication of KB cells were observed to undergo a gradual but remarkable inhibition when exposed to various concentrations. Specifically, concentrations of 6.25, 12.5, 25, 50, 100, and 200 μg/mL exhibited a significant suppressive effect on the proliferation of KB cells. The inhibition of cell proliferation exhibited a statistically significant difference between the extracts obtained from acetone and methanol. Flow cytometry results show an increase in apoptosis of OSCC cells by acetone extract. R. sinensis exerted a concentration-dependent inhibitory effect on the migration of OSCC cells. The chemical composition of R. sinensis was investigated using liquid chromatography positive ion electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS), and 33 compounds in the acetone and methanol extracts of R. sinensis were detected.

CONCLUSION

The findings provide evidence supporting the beneficial effects of R. sinensis extract on inducing apoptosis in OSCC cells and exerting anti-cancer properties.

Neoadjuvant immunochemotherapy for locally advanced resectable oral squamous cell carcinoma: a prospective single-arm trial (Illuminate Trial)

BACKGROUND

Locally advanced oral squamous cell carcinoma (LAOSCC) is associated with a high rate of recurrence and poor survival. Given the recent successes of neoadjuvant immunochemotherapy (NAICT) in solid tumors, it is promising to use this treatment modality to achieve a better pathological response and improve the survival of LAOSCC, and clinical evidence is needed to assess its safety and efficacy.

PATIENTS AND METHODS

A prospective trial of NAICT with toripalimab (PD-1 inhibitor) and albumin paclitaxel/cisplatin (TTP) was conducted in patients with clinical stage III and IVA OSCC. Intravenous albumin paclitaxel (260 mg/m 2 ), cisplatin (75 mg/m 2 ), and toripalimab (240 mg) were given in sequence on day 1 of each 21 day cycle for two cycles, followed by radical surgery and risk-adapted adjuvant (chemo)radiotherapy. The primary endpoints were safety and major pathological response (MPR). Targeted next generation sequencing and multiplex immunofluorescence were performed to assess clinical molecular characteristics and the tumor immune microenvironment in the pre-NAICT and post-NAICT tumor samples.

RESULTS

Twenty patients were enrolled. NAICT was well-tolerated with a low incidence of grades 3-4 adverse events in three patients. The completion rates of NAICT and subsequent R0 resection were 100%. The MPR rate was 60%, including a 30% pathological complete response. MPR was achieved in all four patients with a combined positive score of PD-L1>10. The density of tertiary lymphatic structure in post-NAICT tumor samples predicted the pathological response to NAICT. During the median 23-month follow-up, the disease-free survival was 90%, and the overall survival was 95%.

CONCLUSIONS

NAICT with the TTP protocol in LAOSCC is feasible and well tolerated, with a promising MPR and no obstruction on subsequent surgery. This trial is supportive of further randomized trials using NAICT in LAOSCC.

Oral Squamous Cell Carcinoma (OSCC) Imitates Denosumab-Induced Osteonecrosis of the Mandibular Alveolus: A Diagnostic Challenge

Oral squamous cell carcinoma (OSCC) may arise in the the alveolar ridge (in a minority of cases). Smoking, chronic mucosal injuries, and poor oral hygiene are involved in its pathogenesis. It mostly occurs to men instead of women and affects the mandible on a 3:2 ratio to the maxilla. The objective of the current study is to present an interesting case of an OSCC of the alveolar ridge mimicking jaw osteonecrosis due to denosumab, resulting in differential diagnostic dilemmas. A 78-year-old female patient, edentulous and bearing total dentures, was referred with a persistent (four months), severely painful, ulcerative lesion in the anterior lateral (right) region of the residual alveolar ridge of the mandible. Medical history referred to a long-term systemic steroid use due to sarcoidosis as well as the subcutaneous use of denosumab for osteoporosis one/month for one year. Cone-beam CT (CBCT) examination was performed where bone resorption was detected and a differential diagnosis of osteonecrosis of the jaws (ONJs) from denosumab or neoplasia was made. A biopsy was carried out, and the histological examination showed that soft tissues and underlying bone were infiltrated by abnormal, confluent, compact islands of malignant squamous cells with intense atypia and numerous mitoses indicating a moderately differentiated OSCC. Denosumab inhibits the binding of receptor activator of nuclear factor ligand (RANKL) to receptor activator of nuclear factor-kappa (RANK); this decreases bone resorption and results in increased bone density. However, denosumab may induce ONJ. The area of exposed bone and abnormal soft tissue alterations may resemble both benign and malignant diseases. Osteonecrosis may mimic OSCC or may even provide the suitable substrate for the development of OSCC. Biopsy as well as bone imaging examination are required to accurately determine the possibility of neoplastic formation and its boundaries in cases of osteonecrosis especially in patients under treatment with denosumab or bisphosphonate-related ONJ (BRONJ).

Factors associated with follow-up attendance of patients with oral squamous cell carcinoma: A retrospective cohort study

BACKGROUND

This study examined the postoperative follow-up attendance of oral squamous cell carcinoma (OSCC) patients, evaluated some of the factors associated with it, and assessed its relationship with early detection of postoperative disease progression.

METHODS

An exploratory retrospective cohort study of 430 OSCC patients was conducted. We examined associations of follow-up attendance within the first year after surgery with selected demographic and clinical factors, and with early detection of disease progression.

RESULTS

The mean number of follow-up visits within the first year after surgery was 3.9 out of the 12 recommended at our center; few patients were fully adherent. Age ≥70 years, unmarried status, high education level, and negative history of surgery for premalignant or malignant lesions from oral cavity or other sites were significantly associated with lower follow-up attendance. Greater follow-up attendance was significantly associated with early detection of disease progression during the first year after surgery (p = 0.025).

CONCLUSIONS

Adherence to follow-up visits was poor. Several sociodemographic and clinical factors were related to follow-up attendance, greater follow-up attendance was significantly associated with early detection of disease progression, and these should be further explored in future research.

Changing Epidemiology of Oral Cavity Cancer in the United States

OBJECTIVE

We aim to more accurately characterize the current distribution and rates of squamous cell carcinoma (SCC) cases across various oral cavity subsites in the United States.

STUDY DESIGN

Retrospective cohort.

SETTING

Database study evaluating cancer incidence in the United States from 2001 to 2017.

METHODS

We utilized the US Cancer Statistics Public Use Database, which includes deidentified cancer data reported to the Centers for Disease Control and Prevention's National Program of Cancer Registries and the National Cancer Institute's SEER (Surveillance, Epidemiology, and End Results), capturing 97% of newly diagnosed cancers. We restricted our analysis to SCC arising from oral cavity subsites from 2001 to 2017. We calculated trends in annual cancer incidence rates using SEER*Stat, as well as annual and average annual percentage change and joinpoints with the National Cancer Institute's Joinpoint program.

RESULTS

Most oral cavity SCC cases arise from the oral tongue (41.7%), followed equally by lip and floor of mouth (each 16.5%), gingival (10.6%), buccal (6.7%), retromolar trigone (5.6%), and hard palate (2.3%) involvement. The overall incidence of oral tongue SCC continues to rise with an average annual percentage change of 1.8% (95% CI, 1.6%-2.1%; P < .001), with a 2.3% increase among women. This increase is seen among males and females of all age groups. Cancers involving the gum, buccal mucosa, and hard palate were also found to be increasing in rate, albeit to a lesser degree and with substantially lower incidence.

CONCLUSIONS

The tongue is the most frequently involved subsite of oral cavity SCC and is increasing in incidence among males and females of all ages.

Monopolar electrocautery versus sharp dissection in the neck dissection: a retrospective study

The cold scalpel/scissors (CS) and the monopolar electrocautery (ME) are still the most commonly used instruments for neck dissection in head and neck oncology. However, a direct comparison of these techniques does not exist. This study aims to compare these techniques concerning blood loss, the decline of hemoglobin levels, and surgery duration. Data on 200 patients who received tumor resection, neck dissection and either a radial forearm free flap (RFFF)or a primary closure (PC) were examined retrospectively. The patients were divided according to the performed defect closure (RFFF or PC) and the main instrument usedfor the beck dissection (Group 1: RFFF and ME, Group 2: RFFF and CS, Group 3: PC and ME Group 4: PC and CS). The intraoperative blood loss, decline of hemoglobin values and surgery duration were analyzed and compared between the corresponding groups. The patients where the ME was used lost on average 409.93 ml (group 1 vs. 2) and 242.4 ml (group 3 vs. 4) less blood. The median decrease in the hemoglobin levels was by 1.01 g/dL (group 1 vs. 2) and 0.85 g/dL (group 3 vs. 4) lower for the ME. The median surgery duration was by 102 min (group 1 vs. 2) and 83 min (group 3 vs. 4) shorterfor the ME. All differences were statistically significant. Traditional scalpel and scissors used for neck dissection lead to significantly higher blood loss and longer operation time than the monopolar electrocautery.

Silencing LCN2 suppresses oral squamous cell carcinoma progression by reducing EGFR signal activation and recycling

BACKGROUND

EGFR is an important signal involved in tumor growth that can induce tumor metastasis and drug resistance. Exploring targets for effective EGFR regulation is an important topic in current research and drug development. Inhibiting EGFR can effectively inhibit the progression and lymph node metastasis of oral squamous cell carcinoma (OSCC) because OSCC is a type of cancer with high EGFR expression. However, the problem of EGFR drug resistance is particularly prominent, and identifying a new target for EGFR regulation could reveal an effective strategy.

METHODS

We sequenced wild type or EGFR-resistant OSCC cells and samples from OSCC patients with or without lymph node metastasis to find new targets for EGFR regulation to effectively replace the strategy of directly inhibiting EGFR and exert an antitumor effect. We then investigated the effect of LCN2 on OSCC biological abilities in vitro and in vivo through protein expression regulation. Subsequently, we elucidated the regulatory mechanism of LCN2 through mass spectrometry, protein interaction, immunoblotting, and immunofluorescence analyses. As a proof of concept, a reduction-responsive nanoparticle (NP) platform was engineered for effective LCN2 siRNA (siLCN2) delivery, and a tongue orthotopic xenograft model as well as an EGFR-positive patient-derived xenograft (PDX) model were applied to investigate the curative effect of siLCN2.

RESULTS

We identified lipocalin-2 (LCN2), which is upregulated in OSCC metastasis and EGFR resistance. Inhibition of LCN2 expression can effectively inhibit the proliferation and metastasis of OSCC in vitro and in vivo by inhibiting EGFR phosphorylation and downstream signal activation. Mechanistically, LCN2 binds EGFR and enhances the recycling of EGFR, thereby activating the EGFR-MEK-ERK cascade. Inhibition of LCN2 effectively inhibited the activation of EGFR. We translated this finding by systemic delivery of siLCN2 by NPs, which effectively downregulated LCN2 in the tumor tissues, thereby leading to a significant inhibition of the growth and metastasis of xenografts.

CONCLUSIONS

This research indicated that targeting LCN2 could be a promising strategy for the treatment of OSCC.

Microneedles: structure, classification, and application in oral cancer theranostics

Oral cancer is a malignant tumor that threatens the health of individuals on a global scale. Currently available clinical treatment methods, including surgery, radiotherapy, and chemotherapy, significantly impact the quality of life of patients with systemic side effects. In the treatment of oral cancer, local and efficient delivery of antineoplastic drugs or other substances (like photosensitizers) to improve the therapy effect is a potential way to optimize oral cancer treatments. As an emerging drug delivery system in recent years, microneedles (MNs) can be used for local drug delivery, offering the advantages of high efficiency, convenience, and noninvasiveness. This review briefly introduces the structures and characteristics of various types of MNs and summarizes MN preparation methods. An overview of the current research application of MNs in different cancer treatments is provided. Overall, MNs, as a means of transporting substances, demonstrate great potential in oral cancer treatments, and their promising future applications and perspectives of MNs are outlined in this review.

Imaging Recommendations for Diagnosis, Staging, and Management of Oral Cancer

Oral cavity cancers contribute to a majority of cancers in India. Clinical examination alone cannot determine the deeper extent of the disease; therefore, need for cross-sectional imaging including computed tomography and magnetic resonance imaging becomes indispensable for pre-treatment evaluation to decide optimal plan of management. Oral cavity squamous cell cancers (OSCC) can be treated with surgery alone, whereas deep muscle, neurovascular, osseous, or nodal involvement on imaging suggests advanced disease that requires a combination of surgery, radiation, and/or chemotherapy. Because of the complex anatomy of the oral cavity and its surrounding structures, imaging is crucial for locoregional staging and early detection of distant metastases. Imaging plays indispensable role not only in diagnosis but also in planning the management. An optimal guideline paper for developing countries like India is lacking that not only helps standardize the management but will also assist oncologists make reasonable decisions and reduce the unnecessary imaging. This imaging guideline paper will discuss the optimal imaging in diagnosis and management OSCC for Indian subcontinent.

Clinical outcomes for microvascular reconstruction in oral cancers: experience from a single surgical centre

INTRODUCTION

Reconstruction of a surgical defect is an important part of the management of oral cancers. Microvascular free flap construction provides better functional and cosmetic outcomes.

METHODS

Between 2014 and 2020, some 524 patients underwent microvascular reconstruction. Comorbidity variables were scored using the Charlson Comorbidity Index (CCI). Complications were recorded using Clavien-Dindo criteria.

RESULTS

Eighty-three (15.84%), 339 (64.69%) and 102 (19.47%) patients underwent free radial forearm flap, free anterolateral thigh flap and free fibula osteocutaneous flap (FFOCF), respectively. Clavien-Dindo complications of grade III and above were seen in 39 (7.44%) patients. Total flap loss was seen in 18 patients and of these, 16 were salvaged using alternative free flaps or pedicled flaps. On univariate analysis, overall and major complication rates were higher in FFOCF (p=0.171). Major complications significantly more common in patients with a CCI score >4 (p=0.001). Patients aged >65 years had higher rates of complications (p=0.03).

CONCLUSION

Microvascular free tissue transfer is a reliable, safe and gold standard modality in surgical reconstruction and can be replicated in non-institutional settings.

Salivary protein kinase C alpha and novel microRNAs as diagnostic and therapeutic resistance markers for oral squamous cell carcinoma in Indian cohorts

Oral squamous cell carcinoma (OSCC) is the second leading cause of cancer-related morbidity and mortality in India. Tobacco, alcohol, poor oral hygiene, and socio-economic factors remain causative for this high prevalence. Identification of non-invasive diagnostic markers tailored for Indian population can facilitate mass screening to reduce overall disease burden. Saliva offers non-invasive sampling and hosts a plethora of markers for OSCC diagnosis. Here, to capture the OSCC-specific salivary RNA markers suitable for Indian population, we performed RNA-sequencing of saliva from OSCC patients (n = 9) and normal controls (n = 5). Differential gene expression analysis detected an array of salivary RNAs including mRNAs, long non-coding RNAs, transfer-RNAs, and microRNAs specific to OSCC. Computational analysis and functional predictions identified protein kinase c alpha (PRKCA), miR-6087, miR-449b-5p, miR-3656, miR-326, miR-146b-5p, and miR-497-5p as potential salivary indicators of OSCC. Notably, higher expression of PRKCA, miR-6087 and miR-449b-5p were found to be associated with therapeutic resistance and poor survival, indicating their prognostic potential. In addition, sequencing reads that did not map to the human genome, showed alignments with microbial reference genomes. Metagenomic and statistical analysis of these microbial reads revealed a remarkable microbial dysbiosis between OSCC patients and normal controls. Moreover, the differentially abundant microbial taxa showed a significant association with tumor promoting pathways including inflammation and oxidative stress. Summarily, we provide an integrated landscape of OSCC-specific salivary RNAs relevant to Indian population which can be instrumental in devising non-invasive diagnostics for OSCC.

Effects of tobacco on the DNA of smokers and non-smokers affected by OSCC: systematic review and meta-analysis

Scientific evidence about genetic and molecular changes in oral squamous cell carcinoma (OSCC) among smokers and non-smokers is inconclusive. This systematic review and meta-analysis assessed the effects of tobacco on the DNA of individuals with OSCC based on protein mutations. Electronic searches were conducted on PubMed, Ovid, Web of Science, and Scopus to identify observational studies published up to January/2022. The Joanna Briggs Institute tool was used for the critical appraisal of studies. The certainty of the evidence was evaluated. Twenty-three studies assessing 4,060 individuals (2,967 smokers vs. 1,093 non-smokers) were included in this review. Fifteen groups of proteins/genes were investigated. Analysis of the quality of articles revealed low risk of bias in most studies. The certainty of the evidence was very low. The meta-analysis confirmed no significant difference between smokers and non-smokers with respect to damage to GSTM1 (OR: 0.60; 95%CI: 0.30-1.18), GSTT1 (OR: 1.18; 95%CI:0.49-2.83), hydrolase proteins (Ku70 and Ku80) (OR: 0.74; 95%CI: 0.18-3.05), and transferase proteins (GSTM1, GSTT1, GSTM3) (OR: 0.74; 95%CI: 0.47-1.18). Most of the studies included showed that smokers are more likely to exhibit genetic instability. However, the meta-analysis revealed that smokers do not necessarily have more genetic alterations in the DNA than non-smokers.

A study of RNA m6A demethylases in oral epithelial dysplasia and oral squamous cell carcinoma

Purpose

N6-Methyladenosine (m6A) modification is involved in the tumorigenesis of various cancers. However, the roles of RNA m6A demethylases, fat mass and obesity-associated protein (FTO), and AlkB homolog 5 (ALKBH5) in oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC) remain unclear. This study focuses on FTO and ALKBH5 expression by using immunohistochemistry.

Material and methods

Twenty specimens each of OED, OSCC, and normal oral mucosa (NOM) were included. The expression pattern, the number of positive cells, the cell-staining intensity, and the histochemical scoring (H-score) were examined and analyzed.

Results

In all the OED and OSCC specimens, FTO and ALKBH5 were mainly expressed with moderate to strong staining intensity in the nuclei of the abnormal epithelial cells, respectively. Regarding the NOM, both RNA demethylases showed mild cell staining intensity and was present in 50-60% of the specimens. Interestingly, the percentage of cell positivity, the cell-staining intensity, and the H-score of the FTO and ALKBH5 in NOM, OED, and OSCC were increased, respectively (p < 0.001). There was also a positive correlation between the FTO and ALKBH5 expressions in OSCC (r = 0.62, p = 0.003), but not in the NOM and OED.

Conclusion

These results suggest a possible prognostic role of FTO and ALKBH5 expression in the malignant transformation of OED and tumor progression. Further studies are needed to elucidate the mechanisms underlying the roles of FTO and ALKBH5 in carcinogenesis.

Role Played by Paraoxonase-2 Enzyme in Cell Viability, Proliferation and Sensitivity to Chemotherapy of Oral Squamous Cell Carcinoma Cell Lines

Oral squamous cell carcinoma represents the most aggressive and frequent form of head and neck cancer. Due to drug resistance, the 5-year survival rate of patients with advanced disease is less than 50%. In order to identify molecular targets for effective oral cancer treatment, we focused on paraoxonase-2 enzyme. Indeed, based on data previously obtained from preliminary immunohistochemistry and Western blot analyses performed on tissue specimens, the enzyme was found to be upregulated in tumor compared with normal oral mucosa. Therefore, paraoxonase-2 gene silencing was achieved in HSC-3 and HOC621 oral cancer cell lines, and the effect on cell proliferation, viability, apoptosis induction and sensitivity to cisplatin and 5-fluorouracil treatment was evaluated. Fourier Transform InfraRed Microspectroscopy analyzed alterations of cellular macromolecules upon treatment. Enzyme level and cell proliferation were also determined in cisplatin-resistant clones obtained from HOC621 cell line, as well as in parental cells. Reported data showed that paraoxonase-2 knockdown led to a reduction of cell proliferation and viability, as well as to an enhancement of sensitivity to cisplatin, together with the activation of apoptosis pathway. Spectroscopical data demonstrated that, under treatment with cisplatin, oxidative damage exerted on lipids and proteins was markedly more evident in cells down-regulating paraoxonase-2 compared to controls. Interestingly, enzyme expression, as well as cell proliferation were significantly higher in cisplatin-resistant compared with control HOC621 cells. Taken together these results seem to candidate the enzyme as a promising target for molecular treatment of this neoplasm.

Plasmid encoding miRNA-200c delivered by CaCO3-based nanoparticles enhances rat alveolar bone formation

Aim: miRNAs have been shown to improve the restoration of craniofacial bone defects. This work aimed to enhance transfection efficiency and miR-200c-induced bone formation in alveolar bone defects via plasmid DNA encoding miR-200c delivery from CaCO₃ nanoparticles. Materials & methods: The CaCO₃/miR-200c delivery system was evaluated in vitro (microscopy, transfection efficiency, biocompatibility) and miR-200c-induced in vivo alveolar bone formation was assessed via micro-computed tomography and histology. Results: CaCO₃ nanoparticles significantly enhanced the transfection of plasmid DNA encoding miR-200c without inflammatory effects and sustained miR-200c expression. CaCO₃/miR-200c treatment in vivo significantly increased bone formation in rat alveolar bone defects. Conclusion: CaCO₃ nanoparticles enhance miR-200c delivery to accelerate alveolar bone formation, thereby demonstrating the application of CaCO₃/miR-200c to craniofacial bone defects.

RPS3 Promotes the Metastasis and Cisplatin Resistance of Adenoid Cystic Carcinoma

Background

Adenoid cystic carcinoma (ACC) is a malignant tumor in salivary gland tissue, that is characterized by strong invasiveness and lung metastasis, leading to poor survival rates. RPS3 is been reported to be associated with the biological functions of tumor cells. This study explored the regulatory effect of RPS3 in ACC to provide new therapeutic targets for ACC therapy.

Methods

We reviewed the clinical and pathologic data of 73 ACC patients. The expression of RPS3 was examined in ACC by immunohistochemistry. Transwell, wound healing, half-maximal inhibitory concentration (IC50) and other experiments were used to determine the regulatory effect of RPS3 on ACC functions. Coimmunoprecipitation and mass spectrometry analysis were used to detect the binding proteins of RPS3, mechanisms by which RPS3/STAT1/NF-kB signaling regulates ACC behavior were assessed using western blotting (WB), qPCR, etc. To explore the regulatory effect of RPS3 on ACC in vivo, we constructed nude mouse sciatic nerve infiltration model and a lung metastasis model for studies.

Results

High RPS3 expression was associated with metastasis and a poor prognosis in ACC patients. Inhibition of RPS3 expression reduced ACC migration, invasion and cisplatin resistance, and overexpression of RPS3 promoted ACC migration, invasion and cisplatin resistance. Further experiments revealed that RPS3 can activate the STAT1/NF-kB signaling pathway and regulate ACC behavior through binding to STAT1. The incidence of sciatic nerve infiltration and lung metastasis in nude mice after RPS3 knockdown was lower than that of the control group in vivo.

Conclusion

RPS3 is highly expressed and associated with the prognosis and survival of ACC patients. The RPS3/STAT1/NF-kB pathway may play an important regulatory role in ACC migration, invasion and chemoresistance. As a new therapeutic target of ACC, its clinical application value is worthy of attention and further exploration.

Analysis of the Role of Selective Neck Dissection in Clinically Node-Positive T3/T4 Oral Cancers

Introduction

The concept of selective neck dissection (SND) in locally advanced oral cancers is emerging. Contemporary studies support the feasibility of SND in selected node-positive oral cancers with early primaries. Nevertheless, the suitability of SND in clinically node-positive (cN+) oral cancers with advanced primaries (T3/T4) is unknown.

Aim

This study explores if patients with cN+ advanced primaries were suitable candidates for SND by spotting the involved lymph node distribution in various stations of the neck. Secondary objectives were to check if predictive clinicopathological factors for metastases to the neck in general also apply for lymph node metastases to levels IV and V.

Methods

The present retrospective study analysed the distribution of pathologically involved lymph nodes in 134 patients and explored the interrelation of various predictive factors and cervical metastases overall and those specific to levels IV and V.

Results

Level V was involved in 6.7% (6/83) of T4 and none of the T3 primaries. Depth of invasion (DOI), perineural invasion (PNI), and skin invasion were statistically significant predictors for nodal metastases in general on multivariate analysis.

Conclusion

Our analysis supports the option of considering SND, sparing level V in patients with cN+ oral cancers in a subset with T3 primary and nodal stage N2 and below.

Salvage Surgery in Recurrent Oral Squamous Cell Carcinoma

More than half of patients with oral cancer recur even after multimodality treatment and recurrent oral cancers carry a poorer prognosis when compared to other sites of head and neck. The best survival outcome in a recurrent setting is achieved by salvage surgery; however, objective criteria to select an ideal candidate for salvage surgery is difficult to frame, as the outcome depends on various treatment-, tumor-, and patient-related factors. The following is summarizes various tumor- and treatment-related factors that guide our decision-making to optimize oncologic and functional outcomes in surgical salvage for recurrent oral cancers. Short disease-free interval, advanced tumor stage (recurrent and primary), extracapsular spread and positive tumor margins in a recurrent tumor, regional recurrence, and multimodality treatment of primary tumor all portend worse outcomes after surgical salvage. Quality of life after surgical intervention has shown improvement over 1 year with a drastic drop in pain scores. Various trials are underway evaluating the combination of immunotherapy and surgical salvage in recurrent head and neck tumors, including oral cavity, which may widen our indications for salvage surgery with improved survival and preserved organ function.

A Systematic Review of MicroRNA Signatures Associated with the Progression of Leukoplakia with and without Epithelial Dysplasia

Oral cancer is a significant public health issue, being the eighth most common cancer worldwide with over 300,000 cases diagnosed annually. Early diagnosis and adequate management of oral potentially malignant disorders (OPMDs) before transformation into oral squamous cell carcinoma (OSCC) is critical to reduce deaths, morbidity, and to improve overall prognosis. MicroRNAs (miRNAs) are small noncoding RNAs involved in the post-transcriptional regulation of protein expression and implicated in the control of numerous cellular pathways and impacting physiological, developmental, and pathological processes. Dysregulation of miRNAs has been reported in many cancers and has been demonstrated to play a critical role in cancer initiation, progression, apoptosis, invasion and metastasis. This systematic review provides a comprehensive summary of the prevailing literature on miRNA signatures in OPMDs, specifically leukoplakia with or without oral epithelial dysplasia, and their utility in predicting malignant transformation into OSCC. Eighteen articles describing 73 unique and differentially expressed microRNAs met the criteria for inclusion in this review. We reviewed the characteristics and methodology for each of these studies and assessed the sensitivity and specificity of the studied miRNAs in predicting malignant transformation. This systematic review highlights the significant interest in miRNAs and their tremendous potential as prognostic markers for predicting the malignant transformation of OPMDs into OSCC.

Modeling oral cancer screening in the United States population

OBJECTIVES

To evaluate the impact of oral cancer screening if applied to the United States (US) population or various high-risk populations in the US.

METHODS

We modeled the effects of applying an oral cancer screening program to the US population assuming a similar mortality reduction as seen in the randomized Kerala trial. We combined data on the incidence of oral cancer in the Surveillance, End Results, and Epidemiology database, data on the relative risk in various high-risk groups from the Prostate, Lung, Cervical, and Ovarian screening trial, and the National Lung Screening Trial and data on the prevalence of cigarette use from the National Health Interview Survey.

RESULTS

When extrapolating to the US population we predict the number needed to screen to prevent one oral cancer death (NNS) = 9,845 in all individuals aged 35 + . Screening efficiency would increase if applied to higher-risk populations. If oral cancer screening were applied to male ≥ 60 pack-year current smokers or former smokers who have quit within 15 years aged 50-79 we predict a 4.6% reduction in oral cancer mortality with an NNS = 1,485.

CONCLUSIONS

Targeted screening of individuals at high risk for oral cancer has the potential to maximize the efficiency of screening and meaningfully impact oral cancer mortality. We suggest a future screening trial in high-risk individuals be considered to clarify the role of oral cancer screening in the US.

Free Flap Reconstruction and Its Management in Sickle Cell Trait: Lessons Learned from a Case

Oral cancers are amongst the most common cancers in the Indian subcontinent; in India alone, an estimated 1.2 lakh new patients were diagnosed with it. Reconstruction with free flaps slowly gained popularity over time to become the standard for care for treating large head and neck defects. Flap selection is a complex process; more specifically, the preoperative conditions of patients, the extent of the disease, and the resources available are critical considerations to consider when selecting the best reconstructive technique. It is very well established that certain parts of India, especially the tribal area of Central and southern India, have high prevalence of sickle cell trait (SCT) and sickle cell disease compared to the rest of the country. The sickle cell trait poses a potential increase in morbidity in the perioperative care due to surgical stress. Unfortunately, there are no published articles on the management of a free flap in a case of SCT. Here, in this article, we investigate the issues encountered during the perioperative care in a patient who undergone oral cavity composite resection with free fibula reconstruction. SCT screening must be undertaken mainly to identify, mitigate, and manage the adverse events in the perioperative period. The screening test is very inexpensive and has good sensitivity to detect the heterozygous and homozygous disease. We would recommend screening of all the patients hailing from high-risk endemic areas. The free flap in a case of sickle cell trait is not a contraindication, but a surgeon must understand the nuances in the management of complications in such case. Screening for sickle cell trait followed by perioperative blood transfusions, anticoagulation seems beneficial in a patient undergoing free flaps with sickle cell trait.

Multiple Sequential Free Flap Reconstructions of the Head and Neck: A Single-Center Experience

BACKGROUND

Free flap reconstruction is the standard of care in extensive defects of the head and neck area, and although most patients may be treated sufficiently with one flap, recurrence of a malignant tumor or failure of a previous reconstruction may make the use of a second (or more) flap necessary. The aim of this study was to evaluate the indications and success rates of multiple consecutive reconstructive procedures in a large cohort of patients.

METHODS

Nine hundred ninety-six free flap reconstructions were retrospectively analyzed and cases of sequential reconstructions in the same patient were identified. Indications, success rates, perioperative procedures, and frequently used flaps were evaluated.

RESULTS

Two hundred twenty cases of sequential microvascular reconstructions were identified, ranging from two to six flaps per patient. The overall flap success rate was 89.1 percent. A history of diabetes was identified as a risk factor for flap failure (p = 0.029). There was no association of flap loss with the number of reconstructive procedures per patient.

CONCLUSIONS

The use of several free flaps in the same patient is a feasible option for patients suffering from recurrent tumors or to improve quality of life by a secondary reconstruction. A salvage free flap transfer to replace a lost transplant exhibits good success rates.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Outcomes of salvage treatment in patients with recurrent oral squamous cell carcinoma

BACKGROUND

The survival outcomes of different salvage treatments for patients with recurrent oral cancer remain unclear.

METHODS

A total of 556 patients with recurrent oral cancer between 2010 and 2015 were reviewed. Clinical/pathological risk factors and different salvage treatments were analyzed.

RESULTS

The 2-year disease-free survival rates after recurrence in patients not receiving salvage operation (305 patients), receiving salvage operation with (121 patients), and without (130 patients) major pathological risk factors (margin or extranodal extension) were 5.3%, 32.4%, and 77.2%, respectively (p < 0.001). The 2-year overall survival rates were 20.3%, 58.4%, and 89.2%, respectively (p < 0.001). A late-onset recurrence, salvage radiation, and salvage operation were independent factors for good disease-free and overall survival. Salvage radiation showed survival benefits among patients not indicated for salvage operations.

CONCLUSIONS

Salvage operation was the first choice for recurrent oral cancer. Patients who received the salvage operation without major risk factors had the best survival.

Relationship between anemia and oral cancer: a case-control study

The aim of this study was to investigate the occurrence, type and severity of anemia at the time of diagnosis of oral cancer, and its potential association with the degree of tumor cell differentiation. This case-control study used 366 medical records of patients treated at two referral centers for oral cancer diagnosis, specifically: cases (n=70) with a histopathological diagnosis of oral squamous cell carcinoma (OSCC) of the oral cavity, and controls (n=296) with benign oral lesions. Sociodemographic, behavioral, and clinical variables of both groups, as well as complete blood count values, were analyzed by descriptive statistics and crude/adjusted logistic regression. Anemia was detected in 15.7% of the cases and 11.8% of the controls. The presence of anemia had an OR=1.64 (odds ratio) (95%CI 0.54-5.00) for OSCC, with no significantly statistical association. Normocytic anemia was the most prevalent form of anemia when oral cancer was diagnosed (91.4% of the controls and 72.7% of the cases), and moderate to severely low hemoglobin levels were associated with OSCC diagnosis (OR 6.49; 95%CI 1.18-35.24), albeit data on hematological examinations were missing.

Bcl-xL expression and regulation in the progression, recurrence, and cisplatin resistance of oral cancer

BACKGROUND

Bcl-xL is an anti-apoptotic molecule, but its role in the progression and recurrent/ drug-resistant oral squamous cell carcinoma (OSCC) is poorly understood.

MATERIALS AND METHODS

A total of one hundred twenty-five human OSCC tissue specimens including twenty-nine adjacent normals (AN), sixty-nine primary tumors (PT), twenty-seven recurrent chemoradiation resistance (RCRT) samples, and oral tongue SCC derived cisplatin-resistant (CisR SCC-4/-9) cells were used, for this study. Protein/mRNA expression levels of Bcl-xL and its regulation by ERK1/2, Stat-3, p53, NFκB, AP-1 (components: c-Jun, c-Fos, and Fra-2) molecules, and cell viability were measured by immunohistochemistry, Western blot, RT-PCR, and MTT analysis. Further, the individual and synergistic effects of Fra-2 (siRNA) and nimbolide were tested in CisR SCC-4/-9 cells.

RESULTS

Progressive increase of Bcl-xL expression and its transcriptional-deregulation was observed with OSCC progression and resistance. Among all the possible upstream regulators of Bcl-xL, such as ERK1/2, Stat-3, p53, AP-1, and NFκB, the TF AP-1 (r = 0.644, p = 0.0001) showed maximum association with Bcl-xL mRNA expression. Though differential expression of AP-1 components were detected in OSCC specimens, with more striking positive-correction of c-Jun (r = 0.381, p = 0.049), c-Fos (r = 0.139, p = 0.488, ns) and Fra-2 (r = 0.664, p = 0.0001) with Bcl-xL expression observed stronger in RCRT tumor subgroup. Further, knockdown of Fra-2 and the application of plant-based phytochemical nimbolide decreased Bcl-xL expression and induced apoptosis in CisR SCC-4/-9 cells.

CONCLUSION

Collectively, we have demonstrated the role of Bcl-xL and AP-1 (Fra-2), causing OSCC progression and cisplatin resistance. Targeting Bcl-xL upstream pathway along with the application of nimbolide might be beneficial in eliminating drug-resistant OSCC.

Favorable Lip and Oral Cancer Mortality-to-Incidence Ratios in Countries with High Human Development Index and Expenditures on Health

BACKGROUND

The incidence rates of lip and oral cancer have continued to increase, and prognosis is associated with a country's socioeconomic status. The mortality-to-incidence ratio (MIR) is a reasonable indicator of disparities in cancer screening and treatment. In this study, we aimed to understand the association between economic status and cancer prognosis.

METHODS

Data were obtained from the Global Cancer Observatory (GLOBOCAN) and the World Health Organization (WHO). The MIRs were compared to evaluate the correlation with the human development index (HDI), the current health expenditure (CHE), and the ratio of CHE over gross domestic product (CHE/GDP) disparities via Spearman's rank correlation coefficient.

RESULTS

The results showed that Asia had the most cases and deaths. In addition, they showed a significant association (p < 0.001, p = 0.005, and p < 0.001, respectively) of the crude rate (CR) of incidence with the HDI, the CHE, and the CHE/GDP. However, their associations with mortality rate (p = 0.303, p = 0.997, and p = 0.101) were not significant. Regarding the correlation of the MIRs, the results revealed a significant association with the HDI, the CHE, and the CHE/GDP (p < 0.001, p < 0.001, and p < 0.001, respectively).

CONCLUSION

Countries with higher HDI, CHE per capita, and CHE/GDP tend to have lower MIRs, which indicates favorable clinical outcomes.

Extracellular Vesicle-Mediated Chemoresistance in Oral Squamous Cell Carcinoma

Oral Squamous Cell Carcinoma (OSCC) remains a cancer with poor prognosis and high recurrence rate. Even with multimodal treatment options available for OSCC, tumor drug resistance is still a persistent problem, leading to increased tumor invasiveness among OSCC patients. An emerging trend of thought proposes that extracellular vesicles (EVs) play a role in facilitating tumor progression and chemoresistance via signaling between tumor cells. In particular, exosomes and microvesicles are heavily implicated in this process by various studies. Where primary studies into a particular EV-mediated chemoresistance mechanism in OSCC are limited, similar studies on other cancer cell types will be used in the discussion below to provide ideas for a new line of investigation into OSCC chemoresistance. By understanding how EVs are or may be involved in OSCC chemoresistance, novel targeted therapies such as EV inhibition may be an effective alternative to current treatment options in the near future. In this review, the current understandings on OSCC drug mechanisms under the novel context of exosomes and microvesicles were reviewed, including shuttling of miRNA content, drug efflux, alteration of vesicular pH, anti-apoptotic signaling, modulation of DNA damage repair, immunomodulation, epithelial-to-mesenchymal transition and maintenance of tumor by cancer stem cells.

Manoalide Shows Mutual Interaction between Cellular and Mitochondrial Reactive Species with Apoptosis in Oral Cancer Cells

We previously found that marine sponge-derived manoalide induced antiproliferation and apoptosis of oral cancer cells as well as reactive species generations probed by dichloro-dihydrofluorescein diacetate (DCFH-DA) and MitoSOX Red. However, the sources of cellular and mitochondrial redox stresses and the mutual interacting effects between these redox stresses and apoptosis remain unclear. To address this issue, we examined a panel of reactive species and used the inhibitors of cellular reactive species (N-acetylcysteine (NAC)), mitochondrial reactive species (MitoTEMPO), and apoptosis (Z-VAD-FMK; ZVAD) to explore their interactions in manoalide-treated oral cancer Ca9-22 and CAL 27 cells. Hydroxyl (˙OH), nitrogen dioxide (NO₂˙), nitric oxide (˙NO), carbonate radical-anion (CO₃ ^˙-), peroxynitrite (ONOO^-), and superoxide (O₂ ^˙-) were increased in oral cancer cells following manoalide treatments in terms of fluorescence staining and flow cytometry. Cellular reactive species (˙OH, NO₂ ^·, ˙NO, CO₃ ^˙-, and ONOO^-) as well as cellular and mitochondrial reactive species (O₂ ^˙-) were induced in oral cancer cells following manoalide treatment for 6 h. NAC, MitoTEMPO, and ZVAD inhibit manoalide-induced apoptosis in terms of annexin V and pancaspase activity assays. Moreover, NAC inhibits mitochondrial reactive species and MitoTEMPO inhibits cellular reactive species, suggesting that cellular and mitochondrial reactive species can crosstalk to regulate each other. ZVAD shows suppressing effects on the generation of both cellular and mitochondrial reactive species. In conclusion, manoalide induces reciprocally activation between cellular and mitochondrial reactive species and apoptosis in oral cancer cells.

circBICD2 targets miR-149-5p/IGF2BP1 axis to regulate oral squamous cell carcinoma progression

BACKGROUND

Circular RNAs (circRNAs) are related to oral squamous cell carcinoma (OSCC) progression. circRNA bicaudal D cargo adaptor 2 (circBICD2) has been reported to be abnormally expressed in OSCC. However, the function and mechanism of this circRNA in OSCC progression remain largely unknown.

METHODS

circBICD2, microRNA-149-5p (miR-149-5p), and insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) abundances were examined via quantitative reverse transcription polymerase chain reaction or Western blot. The function of circBICD2 was investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), colony formation, flow cytometry, wound healing, transwell, specific kits, Western blot, and xenograft analyses. Dual-luciferase reporter analysis and RNA immunoprecipitation were carried out to analyze the binding interaction.

RESULTS

circBICD2 expression was enhanced in OSCC tissues and cells. circBICD2 silence suppressed OSCC cell proliferation, migration, invasion, and glutaminolysis and facilitated apoptosis. miR-149-5p was targeted via circBICD2 and decreased in OSCC tissues and cells. miR-149-5p knockdown attenuated silence of circBICD2 on the influence of OSCC cell proliferation, apoptosis, migration, invasion, and glutaminolysis. IGF2BP1 was targeted via miR-149-5p, and circBICD2 could regulate IGF2BP1 via miR-149-5p. IGF2BP1 interference constrained OSCC cell proliferation, migration, invasion, and glutaminolysis and promoted apoptosis. circBICD2 silence reduced OSCC cell growth in xenograft model.

CONCLUSION

circBICD2 knockdown repressed OSCC cell proliferation, migration, invasion, and glutaminolysis and increased apoptosis via modulating miR-149-5p/IGF2BP1 axis, which might act as a potential target for OSCC treatment.

Effects of Maackia amurensis seed lectin (MASL) on oral squamous cell carcinoma (OSCC) gene expression and transcriptional signaling pathways

PURPOSE

Oral cancer causes over 120,000 deaths annually and affects the quality of life for survivors. Over 90% of oral cancers are derived from oral squamous cell carcinoma cells (OSCCs) which are generally resistant to standard cytotoxic chemotherapy agents. OSCC cells often exhibit increased TGFβ and PDPN receptor activity compared to nontransformed oral epithelial cells. Maackia amurensis seed lectin (MASL) can target the PDPN receptor and has been identified as a novel agent that can be used to treat oral cancer. However, mechanisms by which MASL inhibits OSCC progression are not yet clearly defined.

METHODS

Here, we performed cell migration and cytotoxicity assays to assess the effects of MASL on OSCC motility and viability at physiologically relevant concentrations. We then performed comprehensive transcriptome analysis combined with transcription factor reporter assays to investigate the how MASL affects OSCC gene expression at these concentration. Key data were then confirmed by western blotting to evaluate the effects of MASL on gene expression and kinase signaling activity at the protein level.

RESULTS

MASL significantly affected the expression of about 27% of approximately 15,000 genes found to be expressed by HSC-2 cells used to model OSCC cells in this study. These genes affected by MASL include members of the TGFβ-SMAD, JAK-STAT, and Wnt-βCTN signaling pathways. In particular, MASL decreased expression of PDPN, SOX2, and SMAD5 at the RNA and protein levels. MASL also inhibited SMAD and MAPK activity, and exhibited potential for combination therapy with doxorubicin and 5-fluorouracil.

CONCLUSIONS

Taken together, results from this study indicate that MASL decreases activity of JAK-STAT, TGFβ-SMAD, and Wnt-βCTN signaling pathways to inhibit OSCC growth and motility. These data suggest that further studies should be undertaken to determine how MASL may also be used alone and in combination with other agents to treat oral cancer.

Secretory clusterin promotes oral cancer cell survival via inhibiting apoptosis by activation of autophagy in AMPK/mTOR/ULK1 dependent pathway

AIMS

Secretory clusterin (sCLU) plays an important role in tumor development and cancer progression. However, the molecular mechanisms and physiological functions of sCLU in oral cancer is unclear. We examined the impact of sCLU-mediated autophagy in cell survival and apoptosis inhibition in oral cancer.

MAIN METHODS

Immunohistochemical analysis was performed to analyze protein expression in patient samples. Autophagy and mitophagy was studied by immunofluorescence microscopy and Western blot. The gain and loss of function was studied by overexpression of plasmid and siRNA approaches respectively. Cellular protection against nutrient starvation and therapeutic stress by sCLU was studied by cell viability, caspase assay and meta-analysis.

KEY FINDINGS

The data from oral cancer patients showed that the expression levels of sCLU, ATG14, ULK1, and PARKIN increased in grade-wise manners. Interestingly, sCLU overexpression promoted autophagy through AMPK/Akt/mTOR signaling pathway leading to cell survival and protection from long exposure serum starvation induced-apoptosis. Additionally, sCLU was demonstrated to interact with ULK1 and inhibition of ULK1 activity by SBI206965 was found to abolish sCLU-induced autophagy indicating critical role of ULK1 in induction of autophagy. Furthermore, sCLU was observed to promote expression of mitophagy-associated proteins in serum starvation conditions to protect cells from nutrient deprivation. The meta-analysis elucidated that high CLU expression is associated with therapy resistance in cancer and we demonstrated that sCLU-mediated mitophagy was revealed to inhibit cell death by cisplatin.

SIGNIFICANCE

The present investigation has highlighted the probable implications of the clusterin-induced autophagy in cell survival and inhibition of apoptosis in oral cancer.

Epidemiology and pathology of oral squamous cell carcinoma in a multi-ethnic population: Retrospective study of 154 cases over 7 years in Qatar

Background

Oral cancer (OC) is a neoplastic process of the oral cavity that has high mortality and significant effects on patients' aesthetics. The majority of OC is oral squamous cell carcinoma (OSCC) and resection remains the most frequent treatment. Recurrence is the main cause of tumor-related mortality.

Material and methods

A retrospective review of patients' charts at Hamad Medical Corporation examined 154 adults who were diagnosed as OSCC and referred to the national head and neck cancer multi-disciplinary team meetings between 2012 and 2018. The data extracted was demographic, pathologic and clinical. All patients with oral cavity tumors other than squamous cell carcinoma were excluded.

Results

Males comprised the majority of the sample, mean age was 46.93 years. Tongue was the most common location. The majority of the patients were diagnosed at early stages, and a small subset of patients had histologically-proven local recurrence.

Conclusion

The young male predominance of OSCC patients in Qatar is unprecedented worldwide. Most patients were non-Qataris, mainly from South Asia. Loss of follow-up was a challenge in assessing the long-term outcomes of OSCC. Our findings suggest the need for a more vigilant surveillance approach to oral lesions particularly in male South-Asian patients, as well as improving the follow-up strategies.

Oncogenes overexpressed in metastatic oral cancers from patients with pain: potential pain mediators released in exosomes

Oral cancer patients experience pain at the site of the primary cancer. Patients with metastatic oral cancers report greater pain. Lack of pain identifies patients at low risk of metastasis with sensitivity = 0.94 and negative predictive value = 0.89. In the same cohort, sensitivity and negative predictive value of depth of invasion, currently the best predictor, were 0.95 and 0.92, respectively. Cancer pain is attributed to cancer-derived mediators that sensitize neurons and is associated with increased neuronal density. We hypothesized that pain mediators would be overexpressed in metastatic cancers from patients reporting high pain. We identified 40 genes overexpressed in metastatic cancers from patients reporting high pain (n = 5) compared to N0 cancers (n = 10) and normal tissue (n = 5). The genes are enriched for functions in extracellular matrix organization and angiogenesis. They have oncogenic and neuronal functions and are reported in exosomes. Hierarchical clustering according to expression of neurotrophic and axon guidance genes also separated cancers according to pain and nodal status. Depletion of exosomes from cancer cell line supernatant reduced nociceptive behavior in a paw withdrawal assay, supporting a role for exosomes in cancer pain. The identified genes and exosomes are potential therapeutic targets for stopping cancer and attenuating pain.

Comparison of contrast-enhanced ultrasound and contrast-enhanced computed tomography for the diagnosis of cervical lymph node metastasis in squamous cell carcinoma of the oral cavity

Early detection of cervical lymph node metastasis (CLNM) from squamous cell carcinoma (SCC) of the oral cavity remains challenging. This prospective study was performed to evaluate the ability of contrast-enhanced ultrasound (CEUS) to detect CLNM from oral cavity SCC. Additionally, its diagnostic value was compared with that of contrast-enhanced computed tomography (CECT). Forty-eight consecutive patients with SCC of the oral cavity were enrolled. All subjects were examined preoperatively with both CEUS and CECT. Subsequently, neck dissections were performed for these patients, and cervical lymph nodes separated from the surgical specimens were assessed histologically. The diagnostic performance of these two examinations was compared based on the results of histopathology. The sensitivity, specificity, accuracy, positive predictive value, negative predictive value, and Youden index for CEUS and CECT were 69.39% vs. 44.90%, 94.71% vs. 97.12%, 89.88%% vs. 87.16%, 75.56% vs. 78.57%, 92.92% vs. 88.21%, and 64.10% vs. 42.02%, respectively. A significant difference was observed in terms of sensitivity (P=0.024) and Youden index (rate difference 22.08%, 95% confidence interval 2.72-41.44%). Therefore, CEUS appears to be a promising diagnostic tool that is superior to CECT for detecting CLNM from SCC of the oral cavity, with a higher sensitivity.

microRNAs in oral cancer: Moving from bench to bed as next generation medicine

Oral cancer is the thirteenth most common cancer in the world, with India contributing to 33% of the global burden. Lack of specific non-invasive markers, non-improvement in patient survival and tumor recurrence remain a major clinical challenge in oral cancer. Epigenetic regulation in the form of microRNAs (miRs) that act as tumor suppressor miRs or oncomiRs has gained significant momentum with the advancement in the field, suggesting the potential for clinical application of miRs in oral cancer. The current review of literature identified miR-21, miR-27a(-3p), miR-31, miR-93, miR-134, miR-146, miR-155, miR-196a, miR-196b, miR-211, miR-218, miR-222, miR-372 and miR-373 to be up-regulated and let-7a, let-7b, let-7c, let-7d, let-7e, let-7f, let-7g, let-7i, miR-26a, miR-99a-5p, miR-137, miR-139-5p, miR-143-3p, miR-184 and miR-375 to be down-regulated in oral cancer. Mechanistic studies have uncovered several miRs that are deregulated at varying levels and in different stages of oral cancer progression, thus providing clinical utility in better diagnosis as well as usefulness in prognosis by identifying patients with poor prognosis or stratifying patients based on responsiveness to chemo- and radio-therapy. Lastly, exogenous modulation of miR expression using miRNA-based drugs in combination with first-line agents may be adopted as a new therapeutic modality to treat oral cancer. Knowledge of miRs and their involvement in key molecular processes, clinical association, responsiveness to therapy and clinical advancement may highlight additional avenues in order to improve patient morbidity and mortality. Furthermore, combinatorial approaches with miR-therapy may be efficacious in oral cancer.

Prognostic factors associated with overall survival in patients with oral cavity squamous cell carcinoma

Background

Low socioeconomic status, increasing age, and poor lifestyle behaviors are associated with poor survival in patients with oral cavity squamous cell carcinoma (OCSCC). To determine the overall survival (OS) and the risk of OCSCC death by tumor subsite.

Material and Methods

A retrospective cohort study of OCSCC patients diagnosed from 2007 to 2009 and treated at a single cancer center in Rio de Janeiro, Brazil. Patient information was obtained from the Hospital Cancer Registry (HCR) database and complemented by individual search of physical and electronic medical records. Descriptive statistics of population characteristics were computed. OS was estimated using the Kaplan-Meier method. Univariate and multivariate Cox proportional hazards regression analyses were used to estimate the risk of death by tumor subsite.

Results

Seven hundred and three patients with OCSCC were identified. Most patients were men (77.4%) with low levels of education (67.5%), who drank (73.9%) and smoked (79.7%). The most prevalent tumor site was the tongue (45.4%), 73.4% of patients had advanced (clinical stage III or IV) OCSCC at diagnosis and 74.1% died during follow-up. For the entire cohort, the OS was 39.1% at two years and 27.9% at five years. The median survival time was 1.4 years (95%CI: 1.2‒1.5). Non-operative treatment (HR: 3.11; 95%CI: 2.26‒4.29; p <0.001), advanced stage (HR 2.14; 95%CI 1.68-2.74; p <0.001), and age >60 years at diagnosis (HR: 1.37; 95%CI: 1.15‒1.64; p <0.001) were independently associated with the risk of death. However, these factors varied by tumour subsite.

Conclusions

Analysis of specific subsites of the oral cavity revealed substantial differences in prognostic factors associated with poor survival in OCSCC.

Key words:Squamous cell carcinoma, oral cavity cancer, survival, prognosis.