Can interventional radiotherapy (brachytherapy) be an alternative to surgery in early-stage oral cavity cancer? A systematic review.

PURPOSE: Brachytherapy (BT), also known as interventional radiotherapy (IRT), has proven its utility in the treatment of localized tumors. The aim of this review was to examine the efficacy of modern BT in early-stage oral cavity cancer (OCC) in terms of local control (LC), overall survival (OS), disease-free survival (DFS), cancer-specific survival (CSS), and safety. METHODS: The SPIDER framework was used, with sample (S), phenomena of interest (PI), design (D), evaluation (E), and research type (R) corresponding to early-stage oral cavity cancer (S); BT (PI); named types of qualitative data collection and analysis (D); LC, OS, DFS, CSS, and toxicity (E); qualitative method (R). Systematic research using PubMed and Scopus was performed to identify full articles evaluating the efficacy of BT in patients with early-stage OCC. The studies were identified using medical subject headings (MeSH). We also performed a PubMed search with the keywords "brachytherapy oral cavity cancer, surgery." The search was restricted to the English language. The timeframe 2002-2022 as year of publication was considered. We analyzed clinical studies of patients with OCC treated with BT alone only as full text; conference papers, surveys, letters, editorials, book chapters, and reviews were excluded. RESULTS: The literature search resulted in 517 articles. After the selection process, 7 studies fulfilled the inclusion criteria and were included in this review, totaling 456 patients with early-stage node-negative OCC who were treated with BT alone (304 patients). Five-year LC, DFS, and OS for the BT group were 60-100%, 82-91%, and 50-84%, respectively. CONCLUSION: In conclusion, our review suggests that BT is effective in the treatment of early-stage OCC, particularly for T1N0 of the lip, mobile tongue, and buccal mucosa cancers, with good functional and toxicity profiles.

Radiation-induced exosomes promote oral squamous cell carcinoma progression via enhancing SLC1A5-glutamine metabolism.

BACKGROUND: Radiotherapy (RT) can drive cancer cells to enter a state of cellular senescence in which cells can secrete senescence-associated secretory phenotype (SASP) and produce small extracellular vesicles (sEVs) to interact with cells in the tumor microenvironment (TME). Tumor-derived sEVs that are taken up by recipient cells contribute to cancer cell metabolic plasticity, resistance to anticancer therapy, and adaptation to the TME. However, how radiation-induced sEVs support oral squamous cell carcinoma (OSCC) progression remains unclear. METHODS: Beta-galactosidase staining and SASP mRNA expression analysis were used to evaluate the senescence-associated activity of OSCC cells after irradiation. Nanoparticle tracking analysis was performed to identify radiation-induced sEVs. Liquid chromatography-tandem mass spectrometry (LC-MS) was used to explore changes in the levels of proteins in radiation-induced sEVs. Cell Counting Kit-8 and colony formation assays were performed to investigate the function of radiation-induced SASP and sEVs in vitro. A xenograft tumor model was established to investigate the functions of radiation-induced sEVs and V-9302 in vivo as well as the underlying mechanisms. Bioinformatics analysis was performed to determine the relationship between glutamine metabolism and OSCC recurrence. RESULTS: We determined that the radiation-induced SASP triggered OSCC cell proliferation. Additionally, radiation-induced sEVs exacerbated OSCC cell malignancy. LC-MS/MS and bioinformatics analyses revealed that SLC1A5, which is a cellular receptor that participates in glutamine uptake, was significantly enriched in radiation-induced sEVs. In vitro and in vivo, inhibiting SLC1A5 could block the oncogenic effects of radiation-induced sEVs in OSCC. CONCLUSION: Radiation-induced sEVs might promote the proliferation of unirradiated cancer cells by enhancing glutamine metabolism; this might be a novel molecular mechanism underlying radiation resistance in OSCC patients.

Metformin Radiosensitizing Effect on Hypoxic Oral Squamous Cell Carcinoma Cells by GAPDH and TAGLN2.

OBJECTIVE: Tumor hypoxia is associated with a poorer prognosis in cancer patients and can diminish the efficacy of radiation therapy (RT). This study investigates the potential of metformin to enhance radiosensitivity in hypoxic cancer cells. METHODS: Preliminary experiments were conducted to validate the impact of hypoxia on radiation response. Reactive oxygen species (ROS) levels, cell migration, and cell death were assessed in hypoxic, radiated cells treated with metformin. Proteomic and ontological analyses were employed to identify molecular targets associated with the radiosensitizing effect of metformin. Proteomic and ontological findings were validated through patient samples and in vitro studies. RESULTS: Metformin amplified cell death, induced DNA fragmentation, decreased cell migration, and elevated ROS levels in hypoxic, radiated cells. Proteomic analyses revealed that GAPDH and TAGLN2 were identified as pivotal targets linked to the radiosensitizing effect of metformin. Oral cancer patients exhibited elevated levels of TAGLN2 and reduced levels of GAPDH. Metformin downregulated TAGLN2 and upregulated GAPDH in hypoxic, radiated cells. Additionally, metformin reduced levels of mutated p53. CONCLUSIONS: This study suggests that metformin can enhance radiosensitivity in hypoxic cells, operating through modulation of GAPDH and TAGLN2. Furthermore, metformin effectively reduces mutated p53 levels in radiated cells under hypoxic conditions.

Successful definitive radiation treatment of refractory canine oral papillomatosis.

This case report describes a three-year-old male intact border collie diagnosed with canine papillomavirus type 1 (CPV-1+) oral papillomas resistant to standard-of-care. With time, he developed lesions consistent with squamous cell carcinoma. Malignant tumors were incompletely excised and treated with definitive external beam radiation therapy (45 Gy, 3 Gy × 15 daily). The remaining oral cavity received 27 Gy (1.8 Gy x 15 daily) to treat the disseminated oral papillomatosis. A temporary treatment delay of 2 weeks was instituted due to grade 3 mucositis. The patient remained in complete remission after 10 months from radiotherapy. No tumor recurrences were noted by the owners after >1 year from treatment.

A retrospective study of chemotherapeutic effect without wide-margin surgery or radiation therapy in dogs with oral malignant melanoma.

Background: Effective treatment for canine oral malignant melanoma (e.g., curative-intent surgery) may not be feasible or radiation therapy may be unavailable. However, chemotherapy is usually an option, and more information is needed regarding its use without adequate local treatments. Objective: Our objective was to investigate the efficacy of chemotherapy in canine oral malignant melanoma without adequate local control, using carboplatin with dose reduction in small-breed dogs and metronomic chemotherapy. Animals and procedure: Client-owned dogs with histopathologically diagnosed oral malignant melanoma were retrospectively enrolled from 2016 to 2022. The chemotherapy protocol in each case was determined by the attending clinician. Results: Thirteen dogs were included. The median progression-free interval of all 13 dogs was 42 d (14 to 953 d). The median overall survival time of dogs with chemotherapy as their only systemic treatment was 181 d (50 to 960 d; n = 11). The median dosage of carboplatin was 250 mg/m2. Response to treatment and clinical stage were significant prognostic factors. Conclusion and clinical relevance: As chemotherapy provided a median survival of 6 mo, it could be considered when adequate local control is infeasible. Earlier clinical stages or achievement of at least stable disease during chemotherapy may indicate better survival in dogs.

Une étude rétrospective de l'effet chimiothérapeutique sur le mélanome malin buccal canin dépourvu de chirurgie et de radiothérapie á large marge : le stade clinique et la réponse au traitement prédisent les résultats du patient. Mise en contexte: Des traitements efficaces pour le mélanome malin oral canin, tels que la chirurgie á visée curative, ne sont parfois pas réalisables ou la radiothérapie n'est pas disponible dans certaines régions. La chimiothérapie reste une option de traitement et davantage d'informations devraient être fournies pour les cas qui n'ont pas eu accés á un traitement local adéquat. Objectif: Cette étude visait á étudier l'efficacité de la chimiothérapie dans le mélanome malin oral canin sans contrôle local adéquat, en utilisant le carboplatine avec réduction de dose chez les chiens de petite race et la chimiothérapie métronomique. Animaux et procédure: Treize chiens appartenant á des clients atteints d'un mélanome malin oral diagnostiqué par histopathologie ont été rétrospectivement inscrits de 2016 á 2022. Le protocole de chimiothérapie a été déterminé par le clinicien traitant. Résultats: L'intervalle médian sans progression des treize chiens était de 42 jours (14­953 jours). La durée médiane de survie globale des chiens ayant reçu une chimiothérapie comme seul traitement systémique était de 181 jours (50­960 jours; n = 11). La dose médiane de carboplatine était de 250 mg/m2. La réponse au traitement et le stade clinique étaient des facteurs pronostiques importants. Conclusion et pertinence clinique: La chimiothérapie pouvait encore être envisagée lorsqu'un contrôle local adéquat était impossible. Des stades cliniques plus précoces ou des patients atteignant au moins une maladie stable pendant la chimiothérapie peuvent indiquer une meilleure survie.(Traduit par les auteurs).

Comparison of a daily and alternate-day photobiomodulation protocol in the prevention of oral mucositis in patients undergoing radiochemotherapy for oral cancer: a triple-blind, controlled clinical trial.

BACKGROUND: Preventive Photobiomodulation Therapy (PBMT) significantly reduces oral mucositis (OM) severity in patients undergoing Radiochemotherapy (RCT) for the treatment of oral cancer, but daily applications generate cost, overload the dental team, and reduce the number of patients assisted.To evaluate the effectiveness of two PBMT protocols in preventing OM in patients undergoing RCT for oral cancer. MATERIAL AND METHODS: 16 patients diagnosed with oral cancer undergoing RCT were included, equally divided into two groups: a group treated daily with PBMT, and another group also submitted to daily treatment, however, performing the application of PBMT every three days, interspersed with a simulation of PBMT (placebo). A red laser was used (~660 nm), 0.1W power, 1J of energy applied per point, 9 points per area (labial mucosa, buccal mucosa, lateral borders of the tongue, body of the tongue, and floor of the mouth) from the beginning of RCT until the end of the oncological treatment. Daily assessments were performed regarding OM scores, the World Health Organization (WHO) pain scale, and the visual analog scale (VAS). Weight, salivary flow (SGAPP), OHIP-14, and DMFT were evaluated on the initial and final days of RT. OM incidence and clinical data were compared by Pearson's chi-square test or Fisher's exact test. Pain and other scale scores were compared using the Mann-Whitney and Friedman/Dunn tests (SPSS v20.0 p<0.05). RESULTS: In the group with PBMT on alternate days, there was an increase in the frequency of grade 2 and grade 3 oral mucositis and an increased risk of grade 2 oral mucositis, in addition to higher mean pain scores and greater reduction in salivary flow. CONCLUSIONS: The daily PBMT protocol proved more effective in controlling the frequency and severity of OM, pain, and salivary flow.

FOXM1-Mediated Regulation of Reactive Oxygen Species and Radioresistance in Oral Squamous Cell Carcinoma Cells.

Radioresistance is a major obstacle to the successful treatment of oral squamous cell carcinoma (OSCC). To help overcome this issue, we have developed clinically relevant radioresistant (CRR) cell lines generated by irradiating parental cells over time, which are useful for OSCC research. In the present study, we conducted gene expression analysis using CRR cells and their parental lines to investigate the regulation of radioresistance in OSCC cells. Based on gene expression changes over time in CRR cells and parental lines subjected to irradiation, forkhead box M1 (FOXM1) was selected for further analysis in terms of its expression in OSCC cell lines, including CRR cell lines and clinical specimens. We suppressed or upregulated the expression of FOXM1 in OSCC cell lines, including CRR cell lines, and examined radiosensitivity, DNA damage, and cell viability under various conditions. The molecular network regulating radiotolerance was also investigated, especially the redox pathway, and the radiosensitizing effect of FOXM1 inhibitors was examined as a potential therapeutic application. We found that FOXM1 was not expressed in normal human keratinocytes but was expressed in several OSCC cell lines. The expression of FOXM1 was upregulated in CRR cells compared with that detected in the parental cell lines. In a xenograft model and clinical specimens, FOXM1 expression was upregulated in cells that survived irradiation. FOXM1-specific small interfering RNA (siRNA) treatment increased radiosensitivity, whereas FOXM1 overexpression decreased radiosensitivity, and DNA damage was altered significantly under both conditions, as well as the levels of redox-related molecules and reactive oxygen species production. Treatment with the FOXM1 inhibitor thiostrepton had a radiosensitizing effect and overcame radiotolerance in CRR cells. According to these results, the FOXM1-mediated regulation of reactive oxygen species could be a novel therapeutic target for the treatment of radioresistant OSCC; thus, treatment strategies targeting this axis might overcome radioresistance in this disease.

lncRNA HOXA11-AS maintains the stemness of oral squamous cell carcinoma stem cells and reduces the radiosensitivity by targeting miR-518a-3p/PDK1.

OBJECTIVE: Oral squamous cell carcinoma (OSCC) is the most prevailing oral malignancy. The lncRNA HOXA11-AS shows prominent roles in OSCC. This study explored the effects of lncRNA HOXA11-AS on regulating OSCC stem cell stemness and radiosensitivity by targeting miR-518a-3p/PDK1. METHODS: Human OSCC cell lines SCC9 and SCC15 were selected. CD133+ cancer stem cells (CSCs) were sorted by immunomagnetic beads. CD133 expression in cells and HOXA11-AS expression in SCC9, SCC15, and CD133+ SCC9, CD133+ SCC15 cells were assessed by flow cytometry and RT-qPCR. HOXA11-AS was silenced/overexpressed in SCC9, SCC15, CD133+ SCC9, and CD133+ SCC15 cells. Cell proliferation, radiosensitivity, invasion, and stem cell sphere formation ability were examined by CCK-8, colony formation, Transwell, and stem cell sphere formation. The levels of stemness-related genes (Oct4, Nanog, Sox2), miR-518a-3p, epithelial-mesenchymal transition (EMT)-related proteins (E-cadherin, Vimentin, N-cadherin), and PDK1 were assessed by RT-qPCR and Western blot assay. RESULTS: HOXA11-AS was up-regulated in SCC9, SCC15, CD133+ SCC9, and CD133+ SCC15 cells. HOXA11-AS silencing inhibited OSCC proliferation and invasion and enhanced radiosensitivity. HOXA11-AS maintained CSC stemness in OSCC. HOXA11-AS silencing reduced CD133+ SCC9 and CD133+ SCC15 stem cell sphere formation ability, reduced stem cell stemness-related gene levels, and inhibited EMT. HOXA11-AS regulated OSCC stem cell stemness and radiosensitivity by targeting miR-518a-3p. PDK1 overexpression annulled the regulatory effects of HOXA11-AS silencing on OSCC cell stem cell stemness and radiosensitivity. CONCLUSION: In vitro lncRNA HOXA11-AS silencing inhibited OSCC stem cell stemness by targeting the miR-518a-3p/PDK1 axis, thus enhancing OSCC cell radiosensitivity.

The T-N tract involvement as a new prognostic factor for PORT in locally advanced oral cavity tumors.

OBJECTIVE: The space comprised between tumor and neck lymph nodes (T-N tract) is one of the main routes of tumor spread in oral cavity tumors. Aim of the study was to investigate the impact of T-N tract involvement on the postoperative radiotherapy (PORT) outcomes. MATERIALS AND METHODS: Patients (pts) treated between 2000 and 2016 with indication to PORT were retrospectively retrieved. Inclusion criteria were: (a) locally advanced tumors of the oral cavity, (b) who received with indication to PORT (c) with a minimum follow-up of six months. RESULTS: One hundred and fifty-seven pts met the inclusion criteria (136 pts treated with PORT and 21 pts not treated with PORT). In the PORT cohort, the T-N tract involvement had no impact on both OS (p = .09) and LRFS (p = .2). Among the non-PORT cohort, both OS (p = .007) and LRFS (p = .017) were worse for pts with positive T-N tract compared to those with negative T-N tract. PORT improved both OS (p = .008) and LRFS (p = .003) in pts with positive T-N tract but not in those with negative T-N tract (p = .36 and p = .37, respectively). CONCLUSIONS: Our results suggest that involvement of T-N tract should be considered as prognostic factors informing the indication to PORT.

Impact of photobiomodulation in a patient-derived xenograft model of oral squamous cell carcinoma.

BACKGROUND: Photobiomodulation therapy (PBMT) is an effective method for the prevention of oral mucositis. However, the effects of PBMT on oral squamous cell carcinoma (OSCC) have not yet been fully elucidated. This study aimed to evaluate the impact of PBMT in an OSCC-patient-derived xenograft (OSCC-PDX) model. METHODS: BALB/c nude mice with OSCC-PDX models were divided into Control, without PBMT (n = 8); Immediate irradiation, PBMT since one week after tumor implantation (n = 6); and Late irradiation, PBMT after tumors reached 200 mm3 (n = 6). OSCC-PDX were daily irradiated (660 nm; 100 mW; 6 J/cm2 ; 0,2 J/point) for 12 weeks. The tumors were collected and submitted to volumetric, histological, immunohistochemistry, and cell cycle analysis. RESULTS: No significant differences in the volumetric measurements (p = 0.89) and in the histopathological grade (p > 0.05) were detected between the groups. The immunohistochemical analysis of Ki-67 (p = 0.9661); H3K9ac (p = 0.3794); and BMI1 (p = 0.5182), and the evaluation of the cell cycle phases (p > 0.05) by flow cytometry also did not demonstrate significant differences between the irradiated and non-irradiated groups. CONCLUSION: In this study, PBMT did not impact the behavior of OSCC-PDX models. This is an important preclinical outcome regarding safety concerns of the use of PBMT in cancer patients.

Need for adjuvant radiotherapy in oral cancer: depth of invasion rather than tumor diameter.

PURPOSE: The 8th edition of the TNM Cancer Staging Manual incorporates depth of invasion (DOI) into the pathologic tumor classification for oral squamous cell carcinoma (OSSC). While deep invading tumors with small tumor diameters (TD) have been categorized as early stage tumors in the 7th edition, they are now upstaged, potentially influencing the decision to initiate adjuvant radiotherapy (RT). METHODS: OSCC patients surgically treated with curative intent between 2010 and 2019 were consecutively included. Tumors were staged based on TD only (according to the 7th edition TNM Cancer Staging Manual), then restaged based solely on DOI. RESULTS: Of the 133 included patients, 58 patients (43.6%) had a different pT-stage when using DOI instead of TD for staging (upstaging in 23.3%). Overall survival (OS) was significantly worse in patients who were upstaged with DOI. In addition, stratification by adjuvant RT showed significant worse OS in upstaged patients without receiving adjuvant RT. CONCLUSIONS: DOI seems to be an import indicator for adjuvant RT in OSCC-patients.

Wound healing after therapy of oral potentially malignant disorders with a 445-nm semiconductor laser: a randomized clinical trial.

OBJECTIVES: Oral potentially malignant disorders (OPMDs) are the most clinically relevant precursor lesions of the oral squamous cell carcinoma (OSCC). OSCC is one of the 15 most common cancers worldwide. OSCC is with its high rate of mortality an important cause of death worldwide. The diagnosis and therapy of clinically relevant precursor lesions of the OSCC is one of the main parts of prevention of this malignant disease. Targeted therapy is one of the main challenges concerning an oncologically safe tissue removal without overwhelming functional and aesthetic impairment. MATERIALS AND METHODS: In this randomized controlled trial, a newly introduced intraoral 445-nm semiconductor laser (2W; cw-mode; SIROLaser Blue, Dentsply Sirona, Bensheim, Germany) was used in the therapy of OPMDs. Duration and course of wound healing, pain, and scar tissue formation were compared to classical cold blade removal with primary suture by measuring remaining wound area, tissue colorimetry, and visual analogue scale. The study includes 40 patients randomized using a random spreadsheet sequence in two groups (n1 = 20; n2 = 20). RESULTS: This comparative analysis revealed a significantly reduced remaining wound area after 1, 2, and 4 weeks in the laser group compared to the cold blade group (p < 0.05). In the laser group, a significantly reduced postoperative pain after 1 week was measured (p < 0.05). CONCLUSION: Laser coagulation of OPMDs with the investigated 445-nm semiconductor laser is a safe, gentle, and predictable surgical procedure with beneficial wound healing and reduced postoperative discomfort. CLINICAL RELEVANCE: Compared to the more invasive and bloody cold blade removal with scalpel, the 445-nm semiconductor laser could be a new functional less traumatic tool in the therapy of OPMDs. The method should be further investigated with regard to the identification of further possible indications. TRAIL REGISTRATION: German Clinical Trials Register No: DRKS00032626.

IRAK2, an Immune and Radiation-Response Gene, Correlates with Advanced Disease Features but Predicts Higher Post-Irradiation Local Control in Non-Metastatic and Resected Oral Cancer Patients.

Gene Ontology (GO) analysis can provide a comprehensive function analysis for investigating genes, allowing us to identify the potential biological roles of genes. The present study conducted GO analysis to explore the biological function of IRAK2 and performed a case analysis to define its clinical role in disease progression and mediating tumor response to RT. Methods: We performed a GO enrichment analysis on the RNA-seq data to validate radiation-induced gene expression. A total of 172 I-IVB specimens from oral squamous cell carcinoma patients were collected for clinical analysis, from which IRAK2 expression was analyzed by immunohistochemistry. This was a retrospective study conducted between IRAK2 expression and the outcomes of oral squamous cell carcinoma patients after radiotherapy treatment. We conducted Gene Ontology (GO) analysis to explore the biological function of IRAK2 and performed a case analysis to define its clinical role in mediating tumor response to radiotherapy. GO enrichment analysis to validate radiation-induced gene expression was performed. Clinically, 172 stage I-IVB resected oral cancer patients were used to validate IRAK2 expression in predicting clinical outcomes. GO enrichment analysis showed that IRAK2 is involved in 10 of the 14 most enriched GO categories for post-irradiation biological processes, focusing on stress response and immune modulation. Clinically, high IRAK2 expression was correlated with adverse disease features, including pT3-4 status (p = 0.01), advanced overall stage (p = 0.02), and positive bone invasion (p = 0.01). In patients who underwent radiotherapy, the IRAK2-high group was associated with reduced post-irradiation local recurrence (p = 0.025) compared to the IRAK2-low group. IRAK2 plays a crucial role in the radiation-induced response. Patients with high IRAK2 expression demonstrated more advanced disease features but predicted higher post-irradiation local control in a clinical setting. These findings support IRAK2 as a potential predictive biomarker for radiotherapy response in non-metastatic and resected oral cancer patients.

Proton Compared to X-Irradiation Induces Different Protein Profiles in Oral Cancer Cells and Their Derived Extracellular Vesicles.

Extracellular vesicles (EVs) are membrane-bound particles released from cells, and their cargo can alter the function of recipient cells. EVs from X-irradiated cells have been shown to play a likely role in non-targeted effects. However, EVs derived from proton irradiated cells have not yet been studied. We aimed to investigate the proteome of EVs and their cell of origin after proton or X-irradiation. The EVs were derived from a human oral squamous cell carcinoma (OSCC) cell line exposed to 0, 4, or 8 Gy from either protons or X-rays. The EVs and irradiated OSCC cells underwent liquid chromatography-mass spectrometry for protein identification. Interestingly, we found different protein profiles both in the EVs and in the OSCC cells after proton irradiation compared to X-irradiation. In the EVs, we found that protons cause a downregulation of proteins involved in cell growth and DNA damage response compared to X-rays. In the OSCC cells, proton and X-irradiation induced dissimilar cell death pathways and distinct DNA damage repair systems. These results are of potential importance for understanding how non-targeted effects in normal tissue can be limited and for future implementation of proton therapy in the clinic.

Cold Atmospheric Plasma Jet Irradiation Decreases the Survival and the Expression of Oncogenic miRNAs of Oral Carcinoma Cells.

Despite recent advancements, therapies against advanced oral squamous cell carcinoma (OSCC) remain ineffective, resulting in unsatisfactory therapeutic outcomes. Cold atmospheric plasma (CAP) offers a promising approach in the treatment of malignant neoplasms. Although the effects of CAP in abrogating OSCC have been explored, the exact mechanisms driving CAP-induced cancer cell death and the changes in microRNA (miRNA) expression are not fully understood. We fabricated and calibrated an argon-CAP device to explore the effects of CAP irradiation on the growth and expression of oncogenic miRNAs in OSCC. The analysis revealed that, in OSCC cell lines following CAP irradiation, there was a significant reduction in viability; a downregulation of miR-21, miR-31, miR-134, miR-146a, and miR-211 expression; and an inactivation of the v-akt murine thymoma viral oncogene homolog (AKT) and extracellular signal-regulated kinase (ERK) signals. Pretreatment with blockers of apoptosis, autophagy, and ferroptosis synergistically reduced CAP-induced cell death, indicating a combined induction of variable death pathways via CAP. Combined treatments using death inhibitors and miRNA mimics, alongside the activation of AKT and ERK following the exogenous expression, counteracted the cell mortality associated with CAP. The CAP-induced downregulation of miR-21, miR-31, miR-187, and miR-211 expression was rescued through survival signaling. Additionally, CAP irradiation notably inhibited the growth of SAS OSCC cell xenografts on nude mice. The reduced expression of oncogenic miRNAs in vivo aligned with in vitro findings. In conclusion, our study provides new lines of evidence demonstrating that CAP irradiation diminishes OSCC cell viability by abrogating survival signals and oncogenic miRNA expression.

PAICS/DYRK3 Multienzyme Interactions as Coregulators of Purinosome Formation and Metabolism on Radioresistance in Oral Squamous Cell Carcinoma.

Oral squamous cell carcinoma (OSCC) is a prevalent type of oral cancer. While therapeutic innovations have made strides, radioresistance persists as a significant hindrance in OSCC treatment. Despite identifying numerous targets that could potentially suppress the oncogenic attributes of OSCC, the exploration of oncogenic protein kinases for cancer therapy remains limited. Consequently, the functions of many kinase proteins in OSCC continue to be largely undetermined. In this research, we aim to disclose protein kinases that target OSCC and elaborate their roles and molecular mechanisms. Through the examination of the kinome library of radiotherapy-resistant/sensitive OSCC cell lines (HN12 and SAS), we identified a key gene, the tyrosine phosphorylation-regulated kinase 3 (DYRK3), a member of the DYRK family. We developed an in vitro cell model, composed of radiation-resistant OSCC, to scrutinize the clinical implications and contributions of DYRK3 and phosphoribosylaminoimidazole carboxylase and phosphoribosylaminoimidazolesuccinocarboxamide synthase (PAICS) signaling in OSCC. This investigation involves bioinformatics and human tissue arrays. We seek to comprehend the role of DYRK3 and PAICS signaling in the development of OSCC and its resistance to radiotherapy. Various in vitro assays are utilized to reveal the essential molecular mechanism behind radiotherapy resistance in connection with the DYRK3 and PAICS interaction. In our study, we quantified the concentrations of DYRK3 and PAICS proteins and tracked the expression levels of key pluripotency markers, particularly PPAT. Furthermore, we extended our investigation to include an analysis of Glut-1, a gene recognized for its linkage to radioresistance in oral squamous cell carcinoma (OSCC). Furthermore, we conducted an in vivo study to affirm the impact of DYRK3 and PAICS on tumor growth and radiotherapy resistance, focusing particularly on the role of DYRK3 in the radiotherapy resistance pathway. This focus leads us to identify new therapeutic agents that can combat radiotherapy resistance by inhibiting DYRK3 (GSK-626616). Our in vitro models showed that inhibiting PAICS disrupts purinosome formation and influences the survival rate of radiation-resistant OSCC cell lines. These outcomes underscore the pivotal role of the DYRK3/PAICS axis in directing OSCC radiotherapy resistance pathways and, as a result, influencing OSCC progression or therapy resistance. Our findings also reveal a significant correlation between DYRK3 expression and the PAICS enzyme in OSCC radiotherapy resistance.

Oral health related quality of life of oral cancer patients treated with radiotherapy alone or with chemotherapy in a tertiary referral centre in Sri Lanka.

BACKGROUND: Oral cancer is the number one cancer among males in Sri Lanka. Radiotherapy is a common treatment modality for oral cancer, but this can affect oral health related quality of life (OHRQOL). This study assessed the OHRQOL and its changes from baseline to the last week of radiotherapy and three months post radiotherapy among oral cancer patients who received this treatment alone or with chemotherapy. METHODS: A prospective longitudinal study was conducted among 90 oral cancer patients awaiting for radiotherapy alone or with chemotherapy. The modified Sinhala version of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Oral Health Module (EORTC QLQ-OH15) was used to gather data related to OHRQOL before radiotherapy. Socio-demographic and clinical data were also recorded. The same cohort of patients were followed up and assessed their OHRQOL during the last week of radiotherapy and three months post radiotherapy. The Modified EORTC QLQ-OH15 assesses the OHRQOL under three domains namely 'Eating problem', 'Gum and speech problem' and 'Soreness', and one item named as 'Teeth'. RESULTS: The majority of the sample (88%) was males. The anterior two-thirds of the tongue (40%) and buccal mucosa (22%) were the most common sites. The median scores of 'Eating problem' domain at baseline, last week of radiotherapy and three months post radiotherapy were 20 (IQR = 6.7-33.3), 100 (IQR = 86.9-100.0) and 66.7 (IQR = 46.7-93.3) respectively. 'Gum and speech problem' was higher during last week of radiotherapy (median, 50.0, IQR, 25.0-58.3) than three months post radiotherapy (median, 8.3, IQR, 0.0-33.3). The changes of OHRQOL between the time frames were statistically significant (p < 0.05). Baseline OHRQOL in relation to 'Gum and speech problem' domain and 'Teeth' item was identified as an influential factor for OHRQOL during last week of radiotherapy. CONCLUSION: The OHRQOL of oral cancer patients who received radiotherapy alone or with chemotherapy had deteriorated from the baseline level to the last week of radiotherapy but then improved at three months post radiotherapy. The OHRQOL however did not return to the baseline level three months post radiotherapy. OHRQOL during the last week of radiotherapy was influenced by the OHRQOL at baseline, civil status and sites of metastasis.

Knowledge and Practice of Radiation Stents for Oral Cancer Patients among the Sudanese's Maxillofacial Surgeons, Prosthodontists, Oncologists, and Radiotherapists.

AIM: To assess the knowledge and practice of radiation stents for oral cancer patients among the Sudanese's maxillofacial surgeons, prosthodontists, oncologists, and radiotherapists in Khartoum state. MATERIALS AND METHODS: A self-administered questionnaire composed of three sections, including the participant's sociodemographic, knowledge, and practice data, was conducted and distributed among the specialists and Registrars of maxillofacial surgery, prosthodontics, oncology, and radiotherapy who were working at the Khartoum Teaching Dental Hospital, the Faculty of Dentistry (University of Khartoum), and the Khartoum Oncology Hospital, respectively, during the study's duration. A cluster sampling technique was used, and within the cluster group, simple randomization was used. The sample size was 137 participants. The participant's knowledge and practice scores were calculated as percentages achieved by dividing the numbers of the accurate answers of the participants by the total number of questions and categorized as good (66.6%-100%), average (33.3%-66.6%), and poor (less than 33.3%). RESULT: The response rate was 80%. Forty five (40.9%) of the respondents were males, and 65 (59.1%) were females. The high-frequency age-group was 30-40 years (59 subjects, 53.6%). Thirty-eight participants (75.5%) were unfamiliar with the radiation stent. The overall knowledge score was poor, with a significant difference between the different groups (p = 0.0001*). Only the prosthodontists reported a good level of knowledge about the radiation stent (73%), while the oncologists and the radiologists showed a zero level of knowledge. Despite this, the practice score of the radiation stent was poor among all groups. The level of knowledge regarding the complications of radiation and the different protective measures among the maxillofacial surgeons, oncologists, and radiotherapists was 55%, 60%, and 50%, respectively, while the prosthodontists reported 70%. Only 27 (24.5%) participants reported a multidisciplinary treatment approach. At the same time, the majority, 59.1%, declared that they do not follow a formal clinical guideline and/or protocol for dental treatment in oral cancer patients. The lack of knowledge and communication between the different health providers were the main barriers preventing the use of radiation stents. CONCLUSION: The knowledge and practice of the radiation stent were poor. A highlighted need was strengthened to improve the training and communication among the multidisciplinary oral cancer team members, and standard clinical guidelines and protocols need to be conducted and followed to improve patient treatment outcomes. CLINICAL SIGNIFICANCE: Radiation stents have a significant role in reducing the complications of radiation therapy. Improving the knowledge and practice of radiation stents will have a substantial influence on the quality of health services provided for the oral cancer patients and their quality of life.

The antioxidative stress regulator Nrf2 potentiates radioresistance of oral squamous cell carcinoma accompanied with metabolic modulation.

Nuclear factor erythroid 2-related factor 2 (Nrf2), which regulates the expression of critical antioxidant proteins, was recently demonstrated to play a key role in cancer progression. Resistance to radiotherapy is a major obstacle in treating oral squamous cell carcinoma (OSCC). However, little is known about the association between Nrf2 and radioresistance in OSCC. Two OSCC cell lines (SAS and HSC-2) and their clinically relevant radioresistant (CRR) clones (SAS-R, HSC-2-R) were used. The effects of Nrf2 downregulation on radiosensitivity and the involvement of glycolysis in Nrf2-mediated radioresistance were evaluated. Immunohistochemistry of phosphorylated Nrf2 (p-Nrf2) was performed in 110 patients with OSCC who underwent preoperative chemoradiotherapy and surgery. Nrf2 was stably upregulated in CRR cells in vitro and in a mouse xenograft model. Moreover, elevated Nrf2 expression was associated with radioresistance. The enhancement of Nrf2-dependent glycolysis and glutathione synthesis was involved in the development of radioresistance. Additionally, p-Nrf2 expression was closely related to the pathological response to chemoradiotherapy, and its expression was predictive of prognosis in patients with advanced OSCC. Our results suggest that Nrf2 plays an important role in the radioresistance of OSCC accompanied by metabolic reprogramming. Targeting Nrf2 antioxidant pathway may represent a promising treatment strategy for highly malignant OSCC.

Adjuvant brachytherapy for oral squamous cell carcinomas: a single-center experience comparing low-dose and pulsed-dose-rate techniques.

OBJECTIVE: This study aims to assess the outcomes of adjuvant interstitial brachytherapy (BT) to the tumor bed for oral cavity squamous cell carcinoma (SCC), and to compare the oncological outcomes and toxicity profile of low-dose-rate (LDR) and pulsed-dose-rate (PDR) BT. DESIGN: This retrospective single-center study included all patients who underwent postoperative LDR- or PDR-BT to the tumor bed as the sole adjuvant treatment for an oral tongue or floor of the mouth SCC between January 2000 and December 2020. RESULTS: A total of 79 patients were eligible for this study. The cohort was divided into an LDR group (n = 38) and a PDR group (n = 41). The median time interval between surgery and brachytherapy was 55 days. Median delivered total dose was 55 Gy and median hospital stay was 5 days. Five patients (8.3%) experienced grade 3-4 early toxicity, 2 in the LDR group and 3 in the PDR group. Late toxicities were present in 28 patients (44.4%) and were dominated by grade 1-2 residual pain and dysesthesia, without a statistical difference between the groups. After a median follow-up of 65.1 months, 5­year local control (LC), disease-free survival (DFS), and overall survival (OS) for the whole cohort were 76.3% (95% CI = 63.4-85.1), 61.6% (95% CI = 49.0-72.0), and 71.4% (95% CI = 58.6-80.8), respectively. CONCLUSION: Adjuvant BT after excision of oral cavity SCC provides satisfactory oncological outcomes along with good tolerance. In our study, PDR-BT showed similar oncological and functional results to LDR-BT in this indication.