Salivary glands are a target for SARS-CoV-2: a source for saliva contamination.

The ability of the new coronavirus SARS-CoV-2 to spread and contaminate is one of the determinants of the COVID-19 pandemic status. SARS-CoV-2 has been detected in saliva consistently, with similar sensitivity to that observed in nasopharyngeal swabs. We conducted ultrasound-guided postmortem biopsies in COVID-19 fatal cases. Samples of salivary glands (SGs; parotid, submandibular, and minor) were obtained. We analyzed samples using RT-qPCR, immunohistochemistry, electron microscopy, and histopathological analysis to identify SARS-CoV-2 and elucidate qualitative and quantitative viral profiles in salivary glands. The study included 13 female and 11 male patients, with a mean age of 53.12 years (range 8-83 years). RT-qPCR for SARS-CoV-2 was positive in 30 SG samples from 18 patients (60% of total SG samples and 75% of all cases). Ultrastructural analyses showed spherical 70-100 nm viral particles, consistent in size and shape with the Coronaviridae family, in the ductal lining cell cytoplasm, acinar cells, and ductal lumen of SGs. There was also degeneration of organelles in infected cells and the presence of a cluster of nucleocapsids, which suggests viral replication in SG cells. Qualitative histopathological analysis showed morphologic alterations in the duct lining epithelium characterized by cytoplasmic and nuclear vacuolization, as well as nuclear pleomorphism. Acinar cells showed degenerative changes of the zymogen granules and enlarged nuclei. Ductal epithelium and serous acinar cells showed intense expression of ACE2 and TMPRSS receptors. An anti-SARS-CoV-2 antibody was positive in 8 (53%) of the 15 tested cases in duct lining epithelial cells and acinar cells of major SGs. Only two minor salivary glands were positive for SARS-CoV-2 by immunohistochemistry. Salivary glands are a reservoir for SARS-CoV-2 and provide a pathophysiological background for studies that indicate the use of saliva as a diagnostic method for COVID-19 and highlight this biological fluid's role in spreading the disease. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Embryonic stem cells markers Oct4 and Nanog correlate with perineural invasion in human salivary gland mucoepidermoid carcinoma.

BACKGROUND: Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy and is successfully treated by surgery and radiation. However, some patients have recurrent tumours and in these cases, few treatments options are available. Cancer stem cells (CSC) have been observed and isolated from different solid tumours based on the expression of stem cell markers. These cells are associated with tumour initiation, progression as well as treatment resistance. In this study, the expression of stem cell markers CD44, Bmi1, Oct4 and Nanog was evaluated in non-neoplastic salivary tissue and in MEC. METHODS: Twenty-eight samples of MEC and their corresponding non-neoplastic salivary tissue were examined by immunohistochemistry and the stem cell markers expression was correlated with histological and clinical parameters. RESULTS: CD44 was expressed in the membrane of serous and mucous acini as well as in the ductal cells in normal gland tissue. Bmi1, Oct4 and Nanog were mainly expressed in ductal structures. In MEC, CD44 and Bmi1 showed strong expression in all types of neoplastic cells and both markers revealed intense expression in tumour invasive front. Oct4 and Nanog protein expression was associated with desmoplasia and perineural invasion. Only Oct4 positive tumours were associated with dissociative growth pattern and committed margins. CONCLUSION: The stem cell markers CD44, Bmi1, Oct4 and Nanog are frequently expressed in MEC in relation to normal salivary gland and Oct4 and Nanog expression may contribute to aggressiveness and worst prognosis in MEC patients.

Fatal hepatocellular carcinoma presenting with oral metastasis in a patient with synchronic primary malignancies of prostate and liver.

BACKGROUND: Hepatocellular carcinoma (HCC) is the most frequent type of liver cancer and its occurrence in the oral cavity as a metastatic neoplasm is a rare event. We describe a fatal case of HCC with oral metastasis in a patient firstly diagnosed with prostatic and hepatic carcinomas. The histopathological examination revealed a hepatocyte-like tumour cells arranged in organoid structures as well as positivity to cytokeratin 8 and Hep Par 1. The present findings highlight the importance of a complete medical evaluation of the patient to identify possible oral repercussions of primary diseases.

GLI3 knockdown decreases stemness, cell proliferation and invasion in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is an extremely aggressive disease associated with a poor prognosis. Previous studies have established that cancer stem cells (CSCs) actively participate in OSCC development, progression and resistance to conventional treatments. Furthermore, CSCs frequently exhibit a deregulated expression of normal stem cell signalling pathways, thereby acquiring their distinctive abilities, of which self-renewal is an example. In this study, we examined the effects of GLI3 knockdown in OSCC, as well as the differentially expressed genes in CSC-like cells (CSCLCs) expressing high (CD44high) or low (CD44low) levels of CD44. The prognostic value of GLI3 in OSCC was also evaluated. The OSCC cell lines were sorted based on CD44 expression; gene expression was evaluated using a PCR array. Following this, we examined the effects of GLI3 knockdown on CD44 and ESA expression, colony and sphere formation capability, stem-related gene expression, proliferation and invasion. The overexpression of genes related to the Notch, transforming growth factor (TGF)ß, FGF, Hedgehog, Wnt and pluripotency maintenance pathways was observed in the CD44high cells. GLI3 knockdown was associated with a significant decrease in different CSCLC fractions, spheres and colonies in addition to the downregulation of the CD44, Octamer-binding transcription factor 4 (OCT4; also known as POU5F1) and BMI1 genes. This downregulation was accompanied by an increase in the expression of the Involucrin (IVL) and S100A9 genes. Cellular proliferation and invasion were inhibited following GLI3 knockdown. In OSCC samples, a high GLI3 expression was associated with tumour size but not with prognosis. On the whole, the findings of this study demonstrate for the first time, at least to the best of our knowledge, that GLI3 contributes to OSCC stemness and malignant behaviour. These findings suggest the potential for the development of novel therapies, either in isolation or in combination with other drugs, based on CSCs in OSCC.

Prognostic implications of CD44, NANOG, OCT4, and BMI1 expression in tongue squamous cell carcinoma.

BACKGROUND: Tongue squamous cell carcinoma (SCC) contains a cell subpopulation referred to as cancer stem cells (CSCs), which are responsible for tumor growth, metastasis, and resistance to chemotherapy and radiotherapy. The CSC markers have been used to isolate these cells and as biomarkers to predict overall survival. METHODS: The CSC markers CD44, NANOG, OCT4, and BMI1 were investigated using reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry and correlated with clinicopathological parameters. RESULTS: The CD44 overexpression was associated with disease-related death (P = 0.02) and worst prognosis. NANOG was upregulated in nontumoral margins and associated with T1/T2 classification, lymph node metastasis, and worst prognosis. OCT4 was associated with lymph node metastasis and worst overall survival. BMI1 and CD44v3 were overexpressed in tongue SCC. Coexpression of CD44++ /NANOG++ was associated with worst overall survival when compared with patients with CD44-/+ /NANOG-/+ . CONCLUSION: The CSC markers might play an important role not only in CSC trait acquisition but also in tongue SCC development and progression.

Cancer stem cell, cytokeratins and epithelial to mesenchymal transition markers expression in oral squamous cell carcinoma derived from ortothopic xenoimplantation of CD44high cells.

Oral squamous cell carcinoma (OSCC) is the most prevalent neoplasia of oral cavity worldwide and prognosis remains unchanged in decades. Recently, different authors reported that head and neck squamous cell carcinomas have a subpopulation of tumor initiating cells that apparently correspond to cancer stem cells (CSC) and are also responsible for tumor growth and metastasis. The purpose of the present study was to investigate the microscopic and phenotypic characteristics of OSCC tumors induced after orthotopic xenoimplantation of SCC9WT cell line and CSC-enriched subpopulation isolated from SCC9 cell line based on high expression of the putative CSC marker CD44. Different numbers of FACS-sorted SCC9 CD44high and CD44low cells as well as SCC9WT (wild type) were transplanted into the tongue of BALB/C nude (NOD/SCID) mice to evaluate their tumorigenic potential. Sixty days post-induction, tumors were morphologically characterized and immunostained for CSC markers (CD44, Nanog and Bmi-1), epithelial-mesenchymal transition (Snail, Slug) and epithelial differentiating cell markers (cytokeratins 4, 13, 15, 17 and 19), as well as E-cadherin and ß-catenin. The data presented here shows that SCC9 CD44high cells have higher ability to form tumors than SCC9 CD44low cells, even when significantly lower numbers of SCC9 CD44high cells were transplanted. Immunoassessment of tumors derived from SCC9 CD44high cells revealed high expression of cytokeratin CK19, ß-catenin, E-cadherin and CD44, and negative or low expression of CK17, CK4, CK15, CK13, Nanog, Bmi-1, Snail and Slug. While tumors derived from SCC9WT showed high expression of CK17, CK19, CD44, Nanog, Bmi-1, Snail and Slug, and negative or low expression of CK4, CK15, CK13, ß-catenin and E-cadherin. Thus, SCC9 CD44high cells were highly tumorigenic, capable of originating heterogeneous tumors and these tumors have a immunohistochemical profile different from those formed by the wild type cell line.

Salivary glands are a target for SARS-CoV-2: a source for salivacontamination

The ability of the new coronavirus SARS-CoV-2 to spread and contaminate is one of the determinants of the COVID-19 pandemic status. SARS-CoV-2 has been detected in saliva consistently, with similar sensitivity to that observed innasopharyngeal swabs. We conducted ultrasound-guided postmortem biopsies in COVID-19 fatal cases. Samples ofsalivary glands (SGs; parotid, submandibular, and minor) were obtained. We analyzed samples using RT-qPCR, immu-nohistochemistry, electron microscopy, and histopathological analysis to identify SARS-CoV-2 and elucidate qual-itative and quantitative viral proles in salivary glands. The study included 13 female and 11 male patients, with amean age of 53.12 years (range 8­83 years). RT-qPCR for SARS-CoV-2 was positive in 30 SG samples from18 patients (60% of total SG samples and 75% of all cases). Ultrastructural analyses showed spherical 70­100 nm viral particles, consistent in size and shape with the Coronaviridae family, in the ductal lining cell cytoplasm,acinar cells, and ductal lumen of SGs. There was also degeneration of organelles in infected cells and the presence of acluster of nucleocapsids, which suggests viral replication in SG cells. Qualitative histopathological analysis showedmorphologic alterations in the duct lining epithelium characterized by cytoplasmic and nuclear vacuolization, as wellas nuclear pleomorphism. Acinar cells showed degenerative changes of the zymogen granules and enlarged nuclei.Ductal epithelium and serous acinar cells showed intense expression of ACE2 and TMPRSS receptors. An anti-SARS-CoV-2 antibody was positive in 8 (53%) of the 15 tested cases in duct lining epithelial cells and acinar cellsof major SGs. Only two minor salivary glands were positive for SARS-CoV-2 by immunohistochemistry. Salivaryglands are a reservoir for SARS-CoV-2 and provide a pathophysiological background for studies that indicate theuse of saliva as a diagnostic method for COVID-19 and highlight this biological uid's role in spreading the disease.© 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Inibidores de mTOR são potencial terapia com alvo em células tronco tumorais para o carcinoma mucoepidermóide / Targeting cancer stem cells by mTOR inhibition in human mucoepidermoid carcinoma

O carcinoma mucoepidermóide (CME) é o tumor mais comum entre as neoplasias malignas de glândula salivar. Recentemente, uma rara população de células com características de multipotência, autorrenovação e potencial tumorigênico, denominadas como células tronco tumorais (CTT), foi descrita no CME. As CTT são resistentes as terapias atuais, e têm sido consideradas responsáveis pela recorrência e metástase, levando a um pior prognóstico para o paciente. A descoberta de que as CTT do CME superexpressam componentes da via de sinalização mTOR, levantou a hipótese que os pacientes poderiam ser beneficiados com o uso inibidores de mTOR como terapia para eliminação das CTT. O objetivo desse estudo foi avaliar o potencial uso de inibidores de mTOR como terapia para o CME com foco em CTT, assim como, investigar o funcionamento da via de sinalização mTOR e os efeitos moleculares do tratamento com inibidores dessa via nas CTT do CME. Foi realizada imuno-histoquímica para p-mTOR e p-S6K-1 em casos de pacientes diagnosticados com CME, os resultados foram correlacionados com os dados clínicos dos pacientes e também foi realizada dupla marcação por imunofluorescência para ALDH/p-mTOR. Estudos in vitro foram realizados em 3 linhagens de CME (UM-HMC-1, -3A, -3B) e com inibidores da via de sinalização mTOR. Após exposição aos inibidores, realizou-se ensaios de western blot (proteínas da via mTOR e BMI-1), citometria de fluxo para ALDH/CD44; salisfera; e apoptose, esse último comparando com quimioterápicos utilizados atualmente. Adicionalmente, foi utilizado o silenciamento genético de mTOR para confirmar os resultados obtidos com inibidores químicos. Por fim, foram realizados ensaios in vivo com as células silenciadas e com o inibidor de mTOR tensirolimo. Os resultados evidenciaram que a via de sinalização mTOR está ativa no CME, é correlacionada com pior prognóstico clínico e está superexpressa nas CTT. O tratamento com inibidores da via mTOR levaram a diminuição da fração de CTT, devido a perda de autorrenovação e apoptose das CTT. A apoptose, junto a diminuição de p-AKT revelada por western blot, sugeriram que esteja ocorrendo inibição de mTORC2 nas CTT, um importante componente na eficácia do tratamento com inibição de mTOR no câncer. Além disso, também houve redução de vasos sanguíneos, nichos das CTT, e diminuição do crescimento tumoral com uso de inibidores ou silenciando mTOR in vivo. Coletivamente, os resultados mostraram que a inibição de mTOR foi capaz de agir nas CTT por mecanismos diretos (indução de apoptose e diminuição da autorrenovação) e indiretamente através da redução de angiogênese, sugerindo que o uso de inibidores de mTOR no tratamento do CME é uma estratégia molecular eficiente para a redução de CTT, e uma potencial terapia adjuvante.