Pharmacological fatty acid synthase inhibitors differently affect the malignant phenotype of oral cancer cells.

Objective: Fatty acid synthase levels are associated with aggressiveness, prognosis, and risk of metastasis in oral squamous cell carcinomas. This enzyme contains seven catalytic domains and its inhibition by synthetic or natural drugs has antineoplastic properties such as C75, which is a synthetic inhibitor of the beta-ketoacyl synthase domain, the antibiotic triclosan, ligand of the enoyl reductase domain, and the antiobesity drug orlistat, which inhibits the thioesterase domain. Here, we sought to investigate and compare the in vitro effects of C75, triclosan, and orlistat on malignant phenotypes of the cell line SCC-9: proliferation, cell cycle, apoptosis, adhesion, migration, and invasion.& nbsp;Design: Half-maximal inhibitory concentration (IC50) was determined using cell viability assays. Cell death and cell cycle progression were analyzed by Annexin V-PE/7-ADD-PerCP labeling and propidium iodide staining, respectively. Cell migration and invasion were assayed by transwells assays and cell adhesion using collagen and fibronectin.& nbsp;Results: C75 showed the lowest IC50 and higher inhibition of lipid droplets at low concentrations and reduced cell motility. Triclosan showed the intermediate IC50 value, excellent reduction of lipid bodies at the IC50 when compared with C75 and orlistat. Also, triclosan reduced cell cycle progression, adhesion, migration, and invasion of SCC-9 and induced the highest levels of apoptosis. Orlistat promoted cell cycle arrest, but showed the lowest induction of apoptosis and did not affected invasion and adhesion of SCC-9.& nbsp;Conclusion: Altogether, despite the particular effects of the analyzed fatty acid synthase inhibitors, triclosan showed to better interfere in tumorigenic phenotypes of SCC-9 cells.Peer reviewe

Extracellular vesicles derived from cancer-associated fibroblasts induce the migration and invasion of oral squamous cell carcinoma

As one of the most abundant constituents of the tumour microenvironment (TME), cancer-associated fibroblasts (CAF) display critical roles during tumour progression and metastasis. Multiple classes of molecules including growth factors, cytokines, proteases and extracellular matrix proteins, are produced by CAF to act as mediators of the stroma-tumour interactions. One of the main channels for this communication is associated with extracellular vesicles (EV), which are secreted particles loaded with protein and genetic information. In this study, we evaluated the effects of EV derived from CAF primary human cell lines (n = 5) on proliferation, survival, migration, and invasion of oral squamous cell carcinoma (OSCC) cells. As controls, EV from human primary-established normal oral fibroblasts (NOF, n = 5) were used. Our in vitro assays showed that CAF-EV significantly induces migration and invasion of OSCC cells and promote a disseminated pattern of HSC-3 cell invasion in the 3D organotypic assay. Furthermore, gene expression analysis of EV-treated cancer cells revealed changes in the pathways associated with tumour metabolism and up-regulation of tumour invasion genes. Our findings suggest a significant role of CAF-EV in promoting the migration and invasion of OSCC cells, which are related to the activation of cancer-related pathways.Peer reviewe

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, Snaill, 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.Peer reviewe

Efeitos da inibição da enzima FAS sobre a proliferação de células derivadas de melanomas

A ácido graxo sintase (FAS) é a principal enzima responsável pela síntese endógena de ácidos graxos de cadeia longa a partir dos precursores acetil-CoA e malonil-CoA. Estudos recentes têm demonstrado que a expressão desta enzima é anormalmente alta em diversas neoplasias malignas humanas, pois sua atividade é necessária para a síntese de fosfolipídios da membrana das células malignas, fato que parece estar associado a uma maior agressividade e pior prognóstico para os portadores de algumas destas doenças. Dentre estas incluem-se os melanomas, neoplasia malignas originadas dos melanócitos da pele e mucosas, que apresentam altas taxas de metástases. O bloqueio irreversível da atividade de FAS nas diversas linhagens tumorais provoca inibição da fase S do ciclo celular e apoptose. A inibição de FAS reduz também o crescimento de tumores em modelos animais. Não há informações na literatura sobre o efeito do bloqueio de FAS em células de meianoma. No presente trabalho, o tratamento de linhagens celulares derivadas de melanomas de origem humana ou murina com cerulenina ou orlistat foi avaliado através da construção de curvas de proliferação. As células foram tratadas pela adição de 2 ou 5 ug/ml de cerulenina (inibidor natural e específico de FAS) ao meio de cultura de células SKMel, A2058 e B16F10, o que provocou significativa inibição do crescimento celular, em comparação com as células controle. Orlistat é uma droga aprovada pela "Food and Drug Admin istration" (FDA) utilizada para o tratamento da obesidade, com atividade inibitória específica sobre a enzima FAS. A adição de 250uM desta droga ao meio de cultura das mesmas linhagens de melanoma também reduziu a proliferação celular. Estes resultados sugerem que a inibição de FAS possa ser um alvo em potencial para a terapia dos melanomas, merecendo estudos futuros mais detalhados