Expression profile of the PI3K-AKT-mTOR pathway in head and neck squamous cell carcinoma: Data from Brazilian population.

OBJECTIVE: The phosphatidylinositol 3-kinase/protein kinase-B/mammalian target of the rapamycin (PI3K-AKT-mTOR) signaling pathway is an important regulator of cell proliferation, survival, and motility. The gain or loss of function of proteins related to this pathway results in the neoplastic transformation in several types of cancers. This study aimed to evaluate the expression profile of the PI3K-AKT-mTOR pathway in patients with head and neck squamous cell carcinoma (HNSCC) and HNSCC cell lines. STUDY DESIGN: The study involved 26 formalin-fixed paraffin-embedded tissue samples from patients with HNSCC. The analysis of immunohistochemical expression of PI3K, AKT, p-mTOR, and phosphatase and tensin homolog (PTEN) proteins was performed by a quantitative assessment. The in vitro gene and protein expression evaluation was performed by real-time polymerase chain reaction and Western blot assay, respectively, in the human cell lines SCC-9 and FaDu. RESULTS: High levels of PI3K, AKT, and p-mTOR were found in most HNSCC tumors. Following this result, we observed low amounts or absence of PTEN in most samples. Additionally, the FaDu cells (pharynx) showed higher AKT expression but lower expression of p-mTOR compared with SCC-9 cells (oral cavity), which hints at a loco-anatomical relevance. CONCLUSION: Overall, this study found increased expression of the PI3K-AKT-mTOR pathway along with evident PTEN reduction in head and neck cancer.

Differences between bisphosphonate-related and denosumab-related osteonecrosis of the jaws: a systematic review.

OBJECTIVE: Bisphosphonates and denosumab are both antiresorptive medications, each with their own mechanism of action; yet both may result in the same adverse effect: medication-related osteonecrosis of the jaw (ONJ). The present systematic review aims to answer the following question: "Are bisphosphonate-related ONJ and denosumab-related ONJ any different, regarding clinical and imaging aspects?" METHODS: This review followed the Joanna Briggs Review's Manual, and the searches were performed on PubMed, Cochrane, Scopus, Web of Science, and Lilacs databases and on the grey literature (ProQuest, Open Grey, and Google Scholar). RESULTS: The searches resulted in 7535 articles that were critically assessed. Based on the selection criteria, seven studies were included in the review: five cross-sectional studies and two randomized clinical trials. A total of 7755 patients composed the final population. An increase in bone sequestra, cortical bone lysis, and bone density was observed in bisphosphonate-related ONJ, while larger bone sequestra, more frequent periosteal reactions, and mandibular canal enhancement were noted in denosumab-related ONJ. CONCLUSION: This systematic review demonstrated that the imaging characteristics of bisphosphonate-related and denosumab-related ONJ are not similar. Although clinically similar conditions, they were found to be radiographically distinct. More studies are necessary to further elucidate these differences.

Curcumin downregulates the PI3K-AKT-mTOR pathway and inhibits growth and progression in head and neck cancer cells.

Curcumin, a polyphenol isolated from the rhizome of Curcuma longa, has been studied because of its antioxidant, antimicrobial, and antiinflammatory properties. This study aimed to evaluate the effects of curcumin on head and neck cancer (HNC) cell lines and how it modulates the PI3K-AKT-mTOR signaling pathway. Dose-response curves for curcumin were established for hypopharynx carcinoma (FaDu), tongue carcinoma (SCC-9), and keratinocytes (HaCaT) cell lines and IC50 values were calculated. Cell cycle and cell death were investigated through flow cytometry. Cytoskeleton organization was assessed through phalloidin+FITC staining. qPCR array and western blot were performed to analyze gene and protein expression. Curcumin reduced cell viability in a dose-dependent and selective manner, induced cell death on SCC-9 cells (necrosis/late apoptosis: 44% curcumin vs. 16.4% vehicle), and arrested cell cycle at phase G2 /M on SCC-9 and FaDu (G2 : SCC-9-19.1% curcumin vs. 13.4% vehicle; FaDu-37.8% curcumin vs. 12.9% vehicle). Disorganized cytoskeleton and altered cell morphology were observed. Furthermore, curcumin downregulated the PI3K-AKT-mTOR signaling pathway by modifying the expression of key genes and proteins. These findings highlight the promising therapeutic potential of curcumin to inhibit HNC growth and progression and to modulate the PI3K-AKT-mTOR pathway.

Loss of PTEN sensitizes head and neck squamous cell carcinoma to 5-AZA-2'-deoxycytidine.

OBJECTIVE: Head and neck squamous cell carcinoma (HNSCC) is an aggressive cancer associated with poor survival. Phosphatase and tensin homolog (PTEN) is a tumor suppressor gene involved in the maintenance of stem cells. DNA methylation is a known epigenetic modification involved in tumor progression. In this study, we investigated the effect of the DNA demethylation agent 5-AZA-2'-deoxycytidine (5-AZA) over HNSCC and its population of cancer stem cells (CSCs) presenting dysfunctional PTEN. STUDY DESIGN: The effects of 5-AZA on HNSCC were evaluated by using WSU-HN13 cells. CSC was assessed by sphere-forming assays, along with the endogenous levels of aldehyde dehydrogenase. The clonogenic potential of tumors was evaluated, along with the protein expression of mTOR signaling and the identification of nuclear factor-κB (NF-κB) and epithelial-mesenchymal transition (EMT)-associated genes, using real-time polymerase chain reaction (PCR). RESULTS: We observed that loss of PTEN enhances tumor biologic behavior, including colony- and tumor sphere-forming abilities. We also found that 5-AZA has an inhibitory effect over the CSCs and molecular markers associated with the NF-κB and EMT pathways. CONCLUSIONS: Our findings suggest that the stratification of treatment of HNSCC based on PTEN status may identify a subset of patients who can benefit from the coadministration of 5-AZA.

Immunotherapy improves efficacy and safety of patients with HPV positive and negative head and neck cancer: A systematic review and meta-analysis.

BACKGROUND: Despite multiple modalities used to management of head and neck squamous cell carcinoma (HNSCC), disease control remains unsatisfactory. Immunotherapy is emerging as a novel therapeutic approach. This systematic review assesses clinical data regarding immunotherapy efficacy and safety. METHODS: Data from 11 clinical trials testing immunotherapy in HNSCC were assessed. We performed the meta-analysis to correlate the overall survival (OS), response rate (RR), adverse effects, HPV status, and PD-L1 expression. RESULTS: Immunotherapy extended OS (hazard ratio = 0.77, p < 0.0001) and RR significantly (risk ratio = 1.41, p = 0.02). Patients with HPV-positive HNSCC exhibited a better RR (risk ratio = 1.29, p = 0.24) and OS (11.5 vs. 6.3 months). PD-L1 positive tumors showed a higher OS (9.9 vs. 6.5 months). Moreover, immunotherapy caused less adverse effects than standard therapy. CONCLUSION: Our results indicate the benefit of immunotherapy for improving RR and OS of HNSCC patients. The benefit is higher in patients with HPV and PD-L1 positive tumors.

Stanniocalcin 2 contributes to aggressiveness and is a prognostic marker for oral squamous cell carcinoma.

Stanniocalcin 2 (STC2), a glycoprotein that regulates calcium and phosphate homeostasis during mineral metabolism, appears to display multiple roles in tumorigenesis and cancer progression. This study aimed to access the prognostic value of STC2 in oral squamous cell carcinoma (OSCC) and its implications in oral tumorigenesis. STC2 expression was examined in 2 independent cohorts of OSCC tissues by immunohistochemistry. A loss-of-function strategy using shRNA targeting STC2 was employed to investigate STC2 in vitro effects on proliferation, apoptosis, migration, invasion, epithelial-mesenchymal transition (EMT) and possible activation of signaling pathways. Moreover, STC2 effects were assessed in vivo in a xenograft mouse cancer model. High expression of STC2 was significantly associated with poor disease-specific survival (HR: 2.67, 95% CI: 1.37-5.21, p = 0.001) and high rate of recurrence with a hazard ratio of 2.80 (95% CI: 1.07-5.71, p = 0.03). In vitro downregulation of STC2 expression in OSCC cells attenuated proliferation, migration and invasiveness while increased apoptotic rates. In addition, the STC2 downregulation controlled EMT phenotype of OSCC cells, with regulation on E-cadherin, vimentin, Snail1, Twist and Zeb2. The reactivation of STC2 was observed in the STC2 knockdown cells in the in vivo xenograft model, and no influence on tumor growth was observed. Modulation of STC2 expression levels did not alter consistently the phosphorylation status of CREB, ERK, JNK, p38, p70 S6K, STAT3, STAT5A/B and AKT. Our findings suggest that STC2 overexpression is an independent marker of OSCC outcome and may contribute to tumor progression via regulation of proliferation, survival and invasiveness of OSCC cells.

Asparaginase induces selective dose- and time-dependent cytotoxicity, apoptosis, and reduction of NFκB expression in oral cancer cells.

Asparaginase is fundamental to the treatment of haematological malignancies. However, little has been studied on the effects that asparaginase could exert on solid tumours. Thus, this study aimed to evaluate the effects of asparaginase on an oral carcinoma cell line. The cytotoxicity of asparaginase in SCC-9 (tongue squamous cell carcinoma) and HaCaT (human keratinocyte) cell lines was evaluated with MTT cell viability assay. The cells were treated with asparaginase at 0.04, 0.16, 0.63, 1.0, 1.5, 2.5, and 5.0 IU/mL. Dose-response curves and IC50 values were obtained and the Tumour Selectivity Index (TSI) was calculated. The effect of asparaginase on procaspase-3 and nuclear factor κB (NFκB) expression was evaluated with western blot because it was reported that the overexpression of NFκB has been shown to contribute to tumour cell survival, proliferation, and migration. Caspase 3/7 staining was performed to identify cell death using flow cytometry. Effective asparaginase concentrations were lower for SCC-9 cells when compared to HaCaT cells. The cytotoxicity results at 48 and 72 hours were significantly different for SCC-9 cells. The TSI indicated that asparaginase was selective for the tumour cells. A decrease in procaspase-3 and NFκB protein levels was observed in SCC-9 cells. Furthermore, asparaginase resulted in significant apoptosis after 48 and 72 hours. Based on these results, asparaginase was cytotoxic in a dose- and time-dependent manner, induces apoptosis, and reduces NFκB expression in oral cancer cells. These results encourage further studies on the effectiveness of this enzyme as a treatment for solid tumours, especially head and neck cancer.

Effects of turmeric and curcumin on oral mucositis: A systematic review.

The aim of this study was to evaluate the effects of turmeric and curcumin in the management of oral mucositis in cancer patients undergoing chemo and/or radiotherapy. The systematic review was reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses. The search was performed in the following database: Cochrane Library, LILACS, LIVIVO, PubMed, Scopus, and Web of Science. A gray literature search was undertaken using Google Scholar, Open Grey, and ProQuest. The methodology of included studies was evaluated by the Meta-Analysis of Statistics Assessment and Review Instrument. After a two-step selection process, four randomized and one nonrandomized clinical trials were included in the analysis. Two studies were categorized as low and three as moderate risk of bias. Turmeric/curcumin was applied topically as a gel or as a mouthwash. Patients treated with turmeric/curcumin experienced reduced grade of mucositis, pain, erythema intensity, and ulcerative area. Current evidence suggests that topical application of turmeric or curcumin is effective in controlling signs and symptoms of oral mucositis. Thus, further investigation is required to confirm the promising effect of turmeric and curcumin in oral inflammatory lesions.

Additive cytotoxic effects of radiation and mTOR inhibitors in a cervical cancer cell line.

The PI3K/AKT/mTOR signaling pathway is frequently activated in HPV-positive cervical squamous cell cancer (CC). This study investigated the biological effects of mTOR inhibitors associated with radiotherapy in a CC cell line (HeLa). A human keratinocyte cell line (HaCaT) was used as control. Temsirolimus, everolimus, resveratrol, curcumin and epigallocatechin gallate (EGCG) were the mTOR inhibitors assessed. The 50% cell cytotoxicity rate (CC50) for each treatment was determined by MTT cell viability assay. Cells were pre-treated with mTOR inhibitors at CC50 followed by radiotherapy (RT) at 2Gy. Cell death profile after treatment with temsirolimus, resveratrol and curcumin was assessed with flow cytometry. Everolimus, temsirolimus, EGCG, resveratrol and curcumin were cytotoxic to HeLa. Radiation induced a statistically significant (p<0.01) supra-additive cytotoxic effect in the cervical cancer cell line when combined with mTOR inhibitors. After a 24-h treatment, EGCG and resveratrol were more cytotoxic to HeLa cells than to HaCaT cells. After 48h of treatment, resveratrol, curcumin and everolimus were more cytotoxic to HeLa cells when compared to HaCaT cells. After 24h, temsirolimus induced late apoptosis or necrosis in HeLa cells. Based on these data, new studies with mTOR inhibitors as treatment options for cervical cancer are recommended, mainly combined to radiotherapy.

In vitro evaluation of wound healing and antimicrobial potential of ozone therapy.

Although ozone therapy is extensively applied when wound repair and antimicrobial effect are necessary, little is known about cellular mechanisms regarding this process. Thus, this study aimed to evaluate ozone cytotoxicity in fibroblasts (L929) and keratinocytes (HaCaT) cell lines, its effects on cell migration and its antimicrobial activity. Cells were treated with ozonated phosphate-buffered saline (8, 4, 2, 1, 0.5 and 0.25 µg/mL ozone), chlorhexidine 0.2% or buffered-solution, and cell viability was determined through MTT assay. The effect of ozone on cell migration was evaluated through scratch wound healing and transwell migration assays. The minimum inhibitory concentrations for Candida albicans and Staphylococcus aureus were determined. Ozone showed no cytotoxicity for the cell lines, while chlorhexidine markedly reduced cell viability. Although no significant difference between control and ozone-treated cells was observed in the scratch assay, a considerable increase in fibroblasts migration was noticed on cells treated with 8 µg/mL ozonated solution. Ozone alone did not inhibit growth of microorganisms; however, its association with chlorhexidine resulted in antimicrobial activity. This study confirms the wound healing and antimicrobial potential of ozone therapy and presents the need for studies to elucidate the molecular mechanisms through which it exerts such biological effects.

In vivo and in vitro effects of curcumin on head and neck carcinoma: a systematic review.

BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) contributes globally to a great number of deaths and morbidity, in spite of new therapeutic strategies. There is a great need of new drugs that are significantly effective and less deleterious to the patients' general health. In this sense, phytotherapy is a tendency, with results pointing to its use as a chemo-preventive and adjuvant therapy. Therefore, the objective of this systematic review was to investigate the effects of curcumin on proliferation and survival of HNSCC. MATERIALS AND METHODS: The search was conducted on six databases: Cochrane, LILACS, EMBASE, MEDLINE, PubMed, and Web of Science. In vitro and in vivo studies that evaluated the effects of curcumin on cell viability, tumor growth, cell cycle and/or cell death pattern in HNSCC cell lines or animal models were selected. RESULTS: Of the 525 initially gathered studies, 30 met the inclusion criteria. These studies demonstrated that curcumin induces cytotoxicity, apoptosis (via intrinsic pathway), and cell cycle arrest in G2 /M phase in HSNCC cell lines. It also reduces tumor measurements in animal models. These events were mostly studied through MTT assay, flow cytometry, and cell cycle- and apoptosis-related proteins expression. CONCLUSION: This systematic review demonstrated that curcumin is effective on HNSCC cell proliferation and survival, reinforcing the currently available evidence that curcumin could be an adjuvant drug in HNSCC treatment.

Combined paclitaxel, cisplatin and fluorouracil therapy enhances ionizing radiation effects, inhibits migration and induces G0/G1 cell cycle arrest and apoptosis in oral carcinoma cell lines.

Although taxels (in particular paclitaxel), cisplatin and fluorouracil (TPF) chemotherapy has been approved for use in the treatment of head and neck squamous cell carcinoma (HNSCC), little is known with regard to the cellular mechanisms of this novel drug association. In order to investigate the reaction of cells to this novel treatment, the present study aimed to examine the cytotoxic effect of TPF in HNSCC cell lines in combination with irradiation, to analyze its effect on cell cycle progression and cell death, and to evaluate its ability to alter cell migration. An MTT assay was used to determine cell viability following TPF and cisplatin treatments in two human HNSCC cell lines (FaDu and SCC-9) and one keratinocyte cell line (HaCaT). The concurrent use of TPF or cisplatin and irradiation was also analyzed. Flow cytometric analysis was utilized to determine the cell cycle distribution and to verify the induction of apoptosis. The capacity of the drugs to alter oral cancer cell migration was also evaluated using a Transwell migration assay. The results indicated that TPF and cisplatin were cytotoxic to all cell lines, and enhanced the effects of ionizing radiation. FaDu cells were significantly more sensitive to the two treatments, and TPF was more cytotoxic than cisplatin for all cells. Flow cytometric analysis revealed that TPF increased the number of cells in G0/G1 phase in the SCC-9 cell line, and indicated apoptotic cell death. The results of the Transwell assay demonstrated that TPF inhibited migration in oral carcinoma cell lines. The results of the present study indicated that TPF functions in oral carcinoma cell lines through the enhancement of ionizing radiation effects, inducing cell cycle arrest at G0/G1 and apoptosis, in addition to inhibiting migration.

Rosiglitazone Inhibits Proliferation and Induces Osteopontin Gene Expression in Human Dental Pulp Cells.

INTRODUCTION: Rosiglitazone (RSG) is a synthetic full agonist of transcription factor peroxisome proliferator activated receptor gamma. Previous studies have suggested an anti-inflammatory effect of RSG on lipopolysaccharide-induced pulp inflammation. However, its role in other cellular events related to pulp repair has not been investigated. Therefore, the aim of the present study was to evaluate the effect of RSG on human dental pulp cell viability, proliferation, migration, and osteoblastic/odontoblastic differentiation. METHODS: Cell proliferation was evaluated by [3H]-thymidine assay. Cell viability was assessed by a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay and by measuring the percentage of apoptotic cells by flow cytometry. Cell migration was estimated by scratch wound healing assay. Mineralization and cell differentiation were evaluated by alizarin red S staining and real-time polymerase chain reaction gene expression assay, respectively. RESULTS: RSG significantly decreased cell proliferation and did not have effect on cell viability, apoptosis/necrosis, or migration. Alizarin red S showed that RSG accelerated calcified nodule formation. Results of real-time polymerase chain reaction demonstrated that RSG upregulated osteopontin expression, whereas expression of dentin sialophosphoprotein, dentin matrix protein-1, and osteocalcin was not affected. CONCLUSIONS: These findings suggest that RSG decreases human dental pulp cell proliferation, while positively regulating osteopontin expression.