Clinical behavior of recurrent pleomorphic adenoma in the palate: a systematic review.

PURPOSE: This systematic review analyzed the clinical behavior and odds of malignancy of the palatal recurrent pleomorphic adenomas. METHODS: Systematic review of patients with recurrent pleomorphic adenoma arising in the palate. Database search: MEDLINE, Scopus, Web of Science, Cochrane, EMBASE, Virtual Health Library, Google Scholar, and OpenGrey. A binomial logistic regression was performed to assess the odds of detecting recurrence five, 10 and 20 years after the treatment of primary tumor. RESULTS: Thirteen studies (n = 18 patients) out of 336 were included. The recurrent pleomorphic adenoma in palate was more common in females (61.6%), average age was 49 years old (range 9-73 years old). Four patients progressed to malignant transformation. The odds ratio (OR) of detecting a recurrence at 10 (OR = 5.57; 95% confidence interval - 95%CI 1.13-27.52), and 20 years (OR = 18.78; 95%CI 3.18-110.84) after treatment of primary pleomorphic adenoma was significantly higher than at one-year follow-up. CONCLUSIONS: The recurrence of pleomorphic adenoma in palate remains a rare event of late occurrence. It mainly affects middle-aged female and carries a risk of malignant transformation. Although uncommon, patients with palatal pleomorphic adenoma should be warned about the possibility of recurrence or malignant transformation of tumor at advanced ages.

The interaction between social determinants of health and cervical cancer survival: A systematic review.

OBJECTIVE: This systematic review aimed to investigate what are the most relevant social determinants of health (SDH), how they are measured, how they interact among themselves and what is their impact on the outcomes of cervical cancer patients. METHODS: Search was performed in PubMed, Scopus, Web of Science, Embase, Cochrane, and Google Scholar databases from January 2001 to September 2022. The protocol was registered at PROSPERO (CRD42022346854). We followed the PICOS strategy: Population- Patients treated for cervical cancer in the United States; Intervention - Any SDH; Comparison- None; Outcome measures- Cancer treatment outcomes related to the survival of the patients; Types of studies- Observational studies. Two reviewers extracted the data following the PRISMA guidelines. Joanna Briggs Institute Critical Appraisal Checklist for Analytical Cross-Sectional Studies was used for risk of bias (ROB) assessment. RESULTS: Twenty-four studies were included (22 had low and 2 had moderate ROB). Most manuscripts analyzed data from public registries (83.3%) and only one SDH (54.17%). The SDH category of Neighborhood was not included in any study. Although the SDH were measured differently across the studies, not being married, receiving treatment at a low-volume hospital, and having public insurance (Medicaid or Medicare) or not being insured was associated with shorter survival of cervical cancer patients in most studies. CONCLUSIONS: There is a deficit in the number of studies comprehensively assessing the impact of SDH on cervical cancer treatment-related outcomes. Marital status, hospital volume and health insurance status are potential predictors of worse outcome.

Clinical behavior of recurrent pleomorphic adenoma in the palate: a systematic review

Purpose: This systematic review analyzed the clinical behavior and odds of malignancy of the palatal recurrent pleomorphic adenomas. Methods: Systematic review of patients with recurrent pleomorphic adenoma arising in the palate. Database search: MEDLINE, Scopus, Web of Science, Cochrane, EMBASE, Virtual Health Library, Google Scholar, and OpenGrey. A binomial logistic regression was performed to assess the odds of detecting recurrence five, 10 and 20 years after the treatment of primary tumor. Results: Thirteen studies (n = 18 patients) out of 336 were included. The recurrent pleomorphic adenoma in palate was more common in females (61.6%), average age was 49 years old (range 9-73 years old). Four patients progressed to malignant transformation. The odds ratio (OR) of detecting a recurrence at 10 (OR = 5.57; 95% confidence interval - 95%CI 1.13-27.52), and 20 years (OR = 18.78; 95%CI 3.18-110.84) after treatment of primary pleomorphic adenoma was significantly higher than at one-year follow-up. Conclusions: The recurrence of pleomorphic adenoma in palate remains a rare event of late occurrence. It mainly affects middle-aged female and carries a risk of malignant transformation. Although uncommon, patients with palatal pleomorphic adenoma should be warned about the possibility of recurrence or malignant transformation of tumor at advanced ages.

The role of granulocyte-macrophage colony-stimulating factor in head and neck cancer.

OBJECTIVE: To review the molecular mechanisms and biological roles of granulocyte-macrophage colony-stimulating factor (GM-CSF) in head and neck squamous cell carcinoma, highlighting its potential clinical applications. DESIGN: The search terms "granulocyte-macrophage colony-stimulating factor", "GM-CSF", "CSF2″ and "head and neck squamous cell carcinoma" or "head and neck cancer" were queried in the PubMed/MEDLINE and Scopus databases. RESULTS: Despite of being a widely expressed cytokine, the number of studies investigating the specific roles of GM-CSF in head and neck cancer was limited. Most of them investigated GM-CSF in conjunction with other cytokines. When studied alone, conflicting findings were observed in head and neck squamous cell carcinoma. GM-CSF has been shown to induce angiogenesis and local tumor invasion. Additionally, it has also been implicated in immune evasion. On the other hand, GM-CSF stimulated the differentiation of dendritic cells, which are responsible for presenting tumor antigens, and for the regulation of T cell function. Even with these paradoxical effects, there are few studies investigating the potential of GM-CSF as adjuvant therapy in head and neck cancer. CONCLUSION: The effects of GM-CSF in head and neck cancer may be pro- or antitumor. Understanding how one arm and not the other is activated is essential to assess the applicability and the safety of this cytokine as a therapeutic agent.

Propranolol inhibits cell viability and expression of the pro-tumorigenic proteins Akt, NF-ĸB, and VEGF in oral squamous cell carcinoma.

BACKGROUND: Propranolol (PPL) has been suggested as an option for the treatment of various types of cancer. However, data regarding its effectiveness against oral cancer are scarce. Thus, we aimed to evaluate the antitumor potential of PPL in oral squamous cell carcinoma (OSCC) in vitro. METHODS: OSCC cell lines, SCC-9, SCC-25, and Cal27, were treated with PPL at different times and concentrations. OSCC cells were treated with PPL alone or in combination with cisplatin (CDDP) or 5-fluorouracil (5-FU). Cell viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The expression of phosphorylated (p)-Akt, p-S6, p-PTEN, p-P65, and VEGF was verified by immunofluorescence. The migratory activity of OSCC cells was evaluated using a wound-healing assay. RESULTS: PPL reduced OSCC cell viability in a dose- and time-dependent manner. Concentrations above 300 µM, 110 µM, and 100 µM for SCC-9, Cal27, and SCC-25, respectively, significantly eliminated tumor cells. The combination of PPL with CDDP and 5-FU enhanced their antitumor effects. There was a modest difference between the use of the IC30 and IC50 of PPL in the combinatory options. PPL downregulated p-P65 NF-ĸB and VEGF expression in SCC-9 and Cal27 cells but not in SCC-25 cells. PPL inhibited the phosphorylation of Akt and s6 and increased the phosphorylation of PTEN in all OSCC cell lines studied. PPL inhibited OSCC cell migration after 24 h of treatment. CONCLUSION: PPL was effective against oral cancer cells and enhanced standard-of-care. PPL inhibited cell viability and the expression of pAkt, NF-ĸB, and VEGF.

Stress hormone norepinephrine incites resistance of oral cancer cells to chemotherapy.

This study investigated whether norepinephrine (NE) and epinephrine (E) interfere in the response of head and neck squamous cell carcinoma (SCC) cell lines to cisplatin and explored the mechanisms of chemoresistance. Head and neck SCC-derived cell lines SCC-9, Cal27, SCC-25, and FaDu were stimulated with NE or E and treated with the inhibitory concentration of cisplatin for 24 h. As for adrenergic receptors (ADRB) inhibition, cells were treated with propranolol. The results showed that, when combined with NE, cisplatin effectiveness against SCC-9 and Cal27 but not SCC-25 and FaDu cells were notably reduced. E did not affect the response of the cells to cisplatin. Further experiments were performed with the responsive SCC-9 and SCC-25 cell lines and the hormone NE. The time course assay showed that stimulation of oral SCC cells with NE decreased the cleavage of caspase-3 and expression of multidrug resistance protein 1 (MDR-1) but only transiently affected ATP-binding cassette (ABC) subfamily G, isoform 2 protein (ABCG2) expression. The expression of cleaved caspase-3 and Bcl-2 were, respectively, decreased and increased by the combination of NE and cisplatin in SCC-9 and Cal27 cells. NE-induced resistance was reverted by previous treatment with propranolol. Expressions of ABCG2, and p-Akt but not of MDR-1, were enhanced by NE plus cisplatin when compared to cisplatin only in both cell lines. Migratory activity of oral SCC cells challenged with cisplatin was not affected by NE. These findings reveal for the first time that stress hormone NE induces resistance of oral cancer cells to cisplatin in vitro through the ADRB/Akt/ABCG2 pathway, pumping the drug out of the cell and inhibiting apoptosis.

Assessment of the knowledge of canalis sinuosus amongst dentists and dental students: An online-based cross-sectional study.

INTRODUCTION: Canalis sinuosus (CS) is a neurovascular canal that corresponds to a small branch of the infraorbital canal. This study aimed at assessing the knowledge and detection performance of CS amongst dentists and dental students. MATERIALS AND METHODS: Four-hundred and five dentists and dental students answered a questionnaire with three parts: 1. Socio-demographical; 2. Clinical cases with cone- beam computed tomography (CBCT) sections showing CS and 3. Previous knowledge about CS. The chi-squared test and Spearman's correlation test were used to compare results as appropriate. p-values below .05 were considered statistically significant. RESULTS: Most participants did not identify CS in any CBCT. There was an association between the number of correct answers and dental specialties. Most individuals had not learned about CS previously. There was an association between past knowledge of CS and gender, highest academic degree, working environment, dental specialty and number of correct answers but not with age or experience in Dentistry. CONCLUSION: This study suggests that most dentists are not aware about CS and do not know how to diagnose it. Previous knowledge about CS positively influenced its identification in CBCT.

Stress hormones promote DNA damage in human oral keratinocytes.

Chronic stress increases the systemic levels of stress hormones norepinephrine and cortisol. As well as tobacco-specific carcinogen NNK (4-(methylnitrosamine)-1-(3-pyridyl)-1-butanone), they can induce expressive DNA damage contributing to the cancer development. However, it is unknown whether stress hormones have genotoxic effects in oral keratinocytes. This study investigated the effects of stress hormones on DNA damage in a human oral keratinocyte cell line (NOK-SI). NOK-SI cells stimulated with norepinephrine or cortisol showed higher DNA damage compared to untreated cells. Norepinephrine-induced DNA damage was reversed by pre-treatment with beta-adrenergic blocker propranolol. Cells treated with NNK combined to norepinephrine displayed reduced levels of caspases 3 and 7. Cortisol also reduced the activity of pro-apoptotic enzymes. NNK or norepinephrine promoted single-strand breaks and alkali-label side breaks in the DNA of NOK-SI cells. Pre-treatment of cells with propranolol abolished these effects. Carcinogen NNK in the presence or absence of cortisol also induced DNA damage of these cells. The genotoxic effects of cortisol alone and hormone combined with NNK were blocked partially and totally, respectively, by the glucocorticoid receptor antagonist RU486. DNA damage promoted by NNK or cortisol and carcinogen combined to the hormone led to intracellular γH2AX accumulation. The effects caused by NNK and cortisol were reversed by propranolol and glucocorticoid receptor antagonist RU486, respectively. Propranolol inhibited the oxidation of basis induced by NNK in the presence of DNA-formamidopyrimidine glycosylase. DNA breaks induced by norepinephrine in the presence or absence of NNK resulted in higher 8OHdG cellular levels. This effect was also induced through beta-adrenergic receptors. Together, these findings indicate that stress hormones induce DNA damage of oral keratinocytes and could contribute to oral carcinogenesis.

Beta-adrenergic pathway activation enhances aggressiveness and inhibits stemness in head and neck cancer.

Chronic stress leads to the activation of the beta-adrenergic pathway. Its activation has been implicated in the progression of different types of cancer but its role on head and neck squamous cell carcinomas (HNSCCs) remains undefined. The aim of this study was to investigate the influence of the beta-adrenergic pathway activation in the progression of HNSCCs and offer a panel of potential treatments for patients with the active beta-adrenergic pathway. Five hundred and twenty TCGA patients with primary HNSCCs were divided in two groups: ADRB2low / SLC6A2low and ADRB2high / SLC6A2high. Differentially expressed genes (DEGs) were identified through differential expression analysis. The association of clinicopathological and genomic features between the groups was analyzed using a bioinformatic approach. Potential drugs for treatment of HNSCC were identified based on the DEGs. There was association between ADRB2 and SLC6A2 expressions with age, race, tumor site, histologic grade, perineural invasion, and HPV p16 status. It was identified 898 DEGs between the groups. High ADRB2/SLC6A2 expression stimulated HNSCC proliferation, adhesion, invasion, and angiogenesis. On the other hand, genes related to cell stemness were downregulated in patients with activation of the beta- adrenergic pathway. Finally, 56 FDA-approved antineoplastic and immunotherapeutic drugs were identified as potential targets for the personalized treatment.

Craniofacial Features in Richieri-Costa-Pereira Syndrome.

OBJECTIVE: Patients with Richieri-Costa-Pereira syndrome (RCPS) present severe craniofacial alterations and frequently require orthodontic and surgical procedures. Thus, this study aims to describe the craniofacial relationships in patients with RCPS. DESIGN: Panoramic radiographs and lateral cephalometric teleradiographs of 7 patients with RCPS and 7 age- and sex-matched nonsyndromic patients were analyzed. Cephalometric measurements were used to determine the size of apical bases, the relationship between them, the pattern of craniofacial growth, and the facial heights of the patients. Interobservers' concordance was verified by intraclass coefficient. For comparison between the groups, paired t test was employed. P values <.05 indicated statistical significance. RESULTS: Average age of patients with RCPS was 18.5 years. Six patients were female. All patients with RCPS had Pierre-Robin sequence while 2 also presented cleft mandible. Most patients with RCPS had missing lower central incisors (100%), lower lateral incisors (85.7%), lower second premolars (85.7%), and/or upper lateral incisors (57.1%). Concordance between observers was excellent for all cephalometric measurements (0.87-0.99). Patients with RCPS presented severe craniofacial alterations when compared to control group: sella-nasion-B point (SNB) angle (73.8o ± 4.86o vs 78.85o ± 4.53o, P = .029), maxillary length (7.89 cm ± 0.58 cm vs 16.36 cm ± 0.75 cm, P = .001), mandibular length (9.90 cm ± 0.46 cm vs 20.61 cm ± 0.45 cm, P = .001), upper anterior face height (5.41 cm ± 0.50 cm vs 9.40 cm ± 0.47 cm, P = .001), lower anterior face height (5.48 cm ± 0.75 cm vs 11.66 cm ± 0.55 cm, P = .001), and posterior face height (6.70 cm ± 0.33 cm vs 13.65 cm ± 1.06 cm, P = .001). There was no difference in SNB, A point-nasion-B point, pogonion-nasion-B point, and mandibular place angles between the groups (P > .05). CONCLUSION: Patients with RCPS present deficient development of maxilla and mandible when compared with nonsyndromic patients.

Relevance of Cone-beam computed tomography on diagnosis and surgical planning of the cementoblastoma.

The cementoblastoma is a rare odontogenic tumor occurring in the mandibular molar and premolar of the patients in the second and third decades of life. Despite its typical benign behavior, this tumor may promote local destruction by perforating the cortical bone and displacing the mandibular canal. This case report shows a 31-year-old man with an aggressive cementoblastoma attached to the apex of the mandibular first molar. Cone-beam computed tomography revealed a hyperdense mass connected to the root of mandibular molar surrounded by a hypodense area. Multiplanar reconstructions showed rupture of buccal bone plate and tumor invasion of the mandibular canal roof. The surgical planning included enucleation of tumor with the first and second molars extractions and the diagnosis of cementoblastoma was confirmed by histopathology. This case report emphasizes the contribution of cone-beam computed tomography on diagnosis and appropriate surgical planning of the cementoblastoma. Key words:Cone-Beam computed tomography, odontogenic tumors, diagnosis.

Canalis sinuosus: An Anatomic Repair that May Prevent Success of Dental Implants in Anterior Maxilla.

Canalis sinuosus (CS) is a neurovascular canal that corresponds to a small branch of the infraorbital canal. It contains the anterior superior alveolar nerve and vessels, supplying the anterior maxilla. Despite having been described 81 years ago, CS is not recognized by many dental practitioners and may be the cause of unintended injuries during dental procedures. The aims of this study are to report a case of a patient who suffered pain due to exposure of the CS, to provide a comprehensive review of other CS cases that were challenging to diagnose, and to propose guidelines for preoperative examination of patients undergoing surgical procedures in the anterior maxilla. The review of the literature revealed six cases, in addition to the one presented here, of unintended or potential damage to CS. Five out of seven cases were related to dental implant placement and resulted in postoperative pain and/or paresthesia. The dental implant was removed in 4 out of the 5 cases. This study reinforces the importance of awareness of CS by dental practitioners and provides a protocol for the preoperative examination of the patient to prevent avoidable injuries to CS.

High p16INK4a immunoexpression is not HPV dependent in oral leukoplakia.

OBJECTIVE: To evaluate the prevalence of HPV DNA detection in fresh tissue from oral leukoplakia by Linear Array assay, and its correlation with p16INK4a immunoexpression in the northwest region of the São Paulo state, Brazil. PATIENTS AND METHODS: Fifty patients diagnosed with oral leukoplakia were included in the study. Sociodemographic, clinicopathologic and lifestyle data, fresh tissue and formalin fixed paraffin embedded (FFPE) tissue samples were collected. The fresh tissue was stored at -80 °C and then submitted to further viral DNA detection by the Linear Array method. Immunohistochemical analysis for the p16INK4a expression was performed. RESULTS: Of the 50 patients included in the study, 62 % were men, and the age ranged from 25 to 82 years. Twenty-three (46 %) were elderly, 46 % were middle-aged adults, and only 12 % were young adults. Most patients were smokers (76 %), 14 % were former smokers, and 10 % were non-smokers. Most patients (56 %) were current drinkers, 22 % were ex-drinkers and 22 % were non-drinkers. Thirty-two percent of the lesions presented some degree of dysplasia. No lesions were positive to HPV by Linear Array detection. Thirty (60 %) OL had p16-low immunoexpression and 20 (40 %) had p16-high immunoexpression. CONCLUSION: HPV was not identified in the population studied. The high p16INK4a immunoexpression is not dependent on HPV in oral leukoplakia. Broader epidemiological studies are required to clarify the geographic variability in the prevalence of HPV in head and neck squamous cell carcinoma and oral potentially malignant lesions.

Sialolitíase em glândula salivar menor: relato de caso e revisão de literatura / Sialolithiasis in minor salivary gland: case report and literature review

A sialolitíase é uma afecção que se caracteriza pela obstrução da glândula salivar ou de seu ducto devido à formação de estruturas calcificadas acometendo predominantemente as glândulas submandibulares e muito raramente as glândulas salivares menores. O objetivo deste trabalho é realizar um relato de caso sobre sialolitíase em glândula salivar menor. Paciente do sexo masculino, leucoderma, 54 anos, se apresentou com queixa principal de "tumor na boca". O exame físico intrabucal revelou um nódulo localizado na mucosa labial do lado superior direito, próximo a comissura, único, medindo aproximadamente 2 centímetros no seu maior diâmetro. A ultrassonografia da região do lábio superior evidenciou a hipótese diagnóstica de corpo estranho. O diagnóstico diferencial e o clínico incluíram reação a corpo estranho. Foi realizada a biópsia excisional e durante o ato cirúrgico, foi encontrado um material endurecido, de aproximadamente 3 mm, de cor amarelada, que foi enviado para análise histopatológica, a qual revelou fragmento mineralizado compatível com sialolito. Com base nos achados clínicos e imaginológicos o diagnóstico foi de sialolitíase. Após três meses de acompanhamento, o paciente se apresentou sem evidência da doença. Esta revisão de literatura e o presente relato permitiram concluir que um exame clínico criterioso associado a exames imaginológicos adequados são essenciais para a obtenção de um diagnóstico clínico correto(AU)

Sialolithiasis is a condition characterized by obstruction of salivary gland or its duct due to formation of calcified structure, predominantly affecting the submandibular glands or, rarely, the minor salivary glands. The main objective is to report a case of sialolithiasis in the minor salivary gland on a male patient, leucoderma,54, and his main complaint was a "tumor in the mouth". Intraoral physical examination revealed a nodule located on labial mucosa of the upper right side of the mouth, near the commissure, single, and its diameter measuring approximately 2 cm. The ultrasound examination on the upper lip region resulted in a strange body. The differencial and clinical diagnosis was included strange body. During the excision biopsy surgery, a hardened material, measuring about 3 mm and yellowish was removed and sent for histopathologic exams and the diagnosis was sialolithiasis. After three mouths' follow-up, the patient was free of the disease. This literature review and the present case concluded that a careful clinical examination associated with imaging and histopathology examinations are essential for obtaining a correct clinical diagnosis(AU)

Extra-Gingival Pyogenic Granuloma Displacing Teeth.

Pyogenic granuloma is a common cause of growth of soft tissue in the oral cavity, especially in the gingiva. It is mainly associated with local and chronic irritants besides hormonal changes during pregnancy. Here, the authors present an unusual patient of an extra-gingival pyogenic granuloma with large dimensions and displacing teeth arising in a male patient. This is an interesting patient to be reported due to its exacerbated and atypical clinical features.

Pemphigus Vulgaris: How to Perform an Oral Biopsy Properly?

Oral biopsy of vesiculobullous diseases such as pemphigus vulgaris often raises questions due to some particularities involving this procedure. The adequate selection of the area to be biopsied defines if the final diagnosis will be reached, being the Achiles heel of the proper management of the patient. Here, the authors report a case of a woman who sought for treatment of generalized oral blisters and ulcers that caused severe pain. She had undergone a previous biopsy by other professionals that was inconclusive. The authors' team diagnosed the patient with pemphigus vulgaris and treated her properly. The authors provide a brief discussion about the adequate oral site to be chosen when dealing with vesiculobullous diseases once it still remains a source of doubts for the dental surgeons.

Luteolin Impacts on the DNA Damage Pathway in Oral Squamous Cell Carcinoma.

Oral squamous cell carcinoma (OSCC) exhibited high chemoresistance to current treatments. Here we aimed at identifying and repositioning approved drugs that could be selectively toxic toward OSCC cells. Through a cell-based drug screening of 1,280 chemical molecules, we selected compounds lethal to oral cancer SCC-25 cells, while sparing normal keratinocyte HaCaT cells. Within the chemical library, the natural flavonoid luteolin was identified as a potent cytotoxic agent against oral cancer cells in vitro, along with metixene hydrochloride and nitazoxanide. Of note, they exhibit low toxicity and high efficiency compared to the standard-of-care, such as cisplatin and the epidermal growth factor receptor inhibitor tyrphostin. From a molecular standpoint, luteolin causes phosphorylation of ataxia telangiectasia mutated (ATM) and H2AX in a DNA repair pathway and can be efficiently combined with a checkpoint kinase (CHK) pharmacological inhibitor. Thus, luteolin emerges as a potent cytotoxic and/or adjuvant therapy in oral cancer, as it is a natural compound presenting better effects in vitro compared to conventional chemotherapeutic agents. Future in vivo exploration is next required to provide the proof-of-concept that luteolin could be an efficient anticancer molecule.

Tongue phlebothrombosis: Pathogenesis and potential risks.

Phlebothrombosis is a thrombus which develops within a vein. About 90% of phlebothrombosis takes place in the extremities and constitutes a risk factor for deep venous thrombosis, a lifethreatening disease. The occurrence of this lesion in the oral cavity is rare. To our knowledge, besides this case, there is only one previously reported case of tongue phlebothrombosis. Here, we report the second case in addition to a comprehensive discussion of the pathogenesis and potential risks of this uncommon lesion.

Reposicionamento de fármacos no câncer de boca: Identificação de possíveis agentes / Drug repositioning for oral cancer: Identifying candidate therapeutic agents

Objetivos: O objetivo deste estudo foi o de identificar compostos seletivamente tóxicos ao carcinoma espinocelular de boca in vitro por meio do reposicionamento de fármacos. Material e Métodos: Por meio de um escaneamento baseado na viabilidade celular de 1.280 fármacos, nós selecionamos três princípios ativos (luteolin, metixene hydrochloride e nitazoxanide) letais às células de câncer de boca SCC-25 e pouco tóxicos às células de queratinócitos cutâneos imortalizados HaCaT. Os fármacos candidatos foram investigados quanto à sua dose- e tempo-resposta bem como comparados e combinados à agentes quimioterápicos padrão por meio do ensaio por colorimetria com brometo de tiazolil azul de tetrazolio (MTT). O impacto dos fármacos na motilidade do SCC-25 e do HaCaT foi verificado pelo ensaio de migração celular e seus mecanismos de ação também foram explorados por meio da verificação dos níveis das proteínas fosforiladas pelo western blotting. Todos os experimentos foram realizados em triplicata e, pelo menos, três vezes independentes. O teste t de student foi utilizado para confrontar as variáveis e nível de significância de 5% foi estabelecido para todos os testes. Resultados: O flavonoide natural luteolin exerceu citotoxicidade potente contra as células de câncer de boca in vitro, apresentando baixa toxicidade ao HaCaT e alta eficiência quando comparado a quimioterápicos como a cisplatina e o AG1478. Do ponto de vista molecular, a luteolin ativou a via de sinalização do dano do DNA e, combinada com um inibidor do Chk, apresentou efeitos potencializados. Além disso, nós demonstramos que a nitazoxanide e o metixene hydrochloride são capazes de destruir células SCC-25 porém não as HaCaT de maneira proporcional à dose e ao tempo de tratamento. As combinações entre os três fármacos hit e com a cisplatina ou o AG1478 potencializaram seus efeitos contra as células malignas. Conclusões: O presente estudo traz a luteolin, o metixene hydrochloride e a nitazoxanide como...

Objectives: Here we aimed at identifying and reposition approved drugs that could be selectively toxic towards oral squamous cell carcinoma cells. Materials and Methods: Through a cell-based drug screening of 1,280 chemical molecules, we selected 3 compounds (luteolin, metixene hydrochloride, and nitazoxanide) lethal to oral cancer SCC-25 cells, while sparing immortalized keratinocyte HaCaT cells. The drugs were then further challenged for their time- and dose-responses, as well as their comparison and combination to standard chemotherapeutic agents by colorimetric assay 1-(4,5-Dimethylthiazol-2-yl)-3,5-diphenylformazan, Thiazolyl blue formazan (MTT). The impact on SCC-25 and HaCaT motility as well as the mode of action of the drugs was then further explored by scratching assay and western blotting, respectively. All the experiments were performed in triplicated and, at least, three independent times. Students t test was performed to verify the differences among the variables and the level of significance was set at 5%. Results: The natural flavonoid luteolin was a potent cytotoxic agent against oral cancer cells in vitro, presenting low toxicity against HaCaT cells and high efficiency as compared to standard-of-care, such as cisplatin and AG1478. From a molecular standpoint, luteolin coopted the DNA-damage pathway and could be efficiently combined with Chk pharmacological inhibitor. Moreover, we demonstrated that nitazoxanide and metixene hydrochloride kill the SCC-25 but not the HaCaT cells in a dose- and time-dependent. The combinations among the three drugs hit and with cisplatin and AG1478 improved their effect against the malignant cells. Conclusions: Luteolin, metixene hydrochloride, and nitazoxanide emerge as strong cytotoxic and/or adjuvant therapy in oral cancer, as these compounds present higher efficiency and lower toxicity against oral cancer cells in vitro than conventional chemotherapeutic agents.