Evaluation of the effects of FASN silencing on the mitochondrial morphology of oral squamous cell carcinoma cell lines (SCC-9 and LN-1A).

• Grant number: 22/14514-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date until: August 01, 2023
• End date until: February 29, 2024
• Field of knowledge: Biological Sciences - Morphology - Histology
• Principal Investigator: Débora Campanella Bastos
• Grantee: Clara Adamoli Zaninetti Caputo
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil

Abstract

Oral squamous cell carcinoma (OSCC) is the most common histological subtype of oral cancer and has a high rate of metastasis and poor survival for patients. The most common form of treatment for OSCC is surgical removal and, in more advanced stages, radiochemotherapeutic protocols may be indicated. The fatty acid synthase enzyme (FASN - fatty acid synthase, EC 2.3.1.85) is responsible for the endogenous synthesis of long-chain fatty acids, being overexpressed in CCEO and associated with greater aggressiveness and risk of metastases for this neoplasm. Several natural or synthetic FASN inhibitors have already been demonstrated to have antiproliferative and antineoplastic properties. Previous results from our research group showed that the antibiotic Triclosan (TCS), which is also considered a FASN inhibitor because it covalently binds to one of its catalytic domains, was able to reduce cell proliferation, migration, invasion and adhesion. SCC-9 more efficiently when compared to the other inhibitors tested (C75 and orlistat). According to the endosymbiotic theory of mitochondrial arising, we can speculate that the greater efficiency of TCS may be associated with inhibitory effects of TCS on mitochondrial FASN, altering the biogenesis of this organelle and its energy metabolism. Our research group recently investigated and demonstrated that the treatment of SCC-9 and LN-1A cells (highly metastatic derivative of SCC-9) with TCS results in important alterations in the mitochondrial morphology of these cells. Despite the important results obtained with TCS treatment on the mitochondrial morphology of malignant OSCC cells, it is important to emphasize that TCS can promote non-specific effects, not yet described, in tumor cells and their mitochondrial metabolism independent of FASN inhibition. Therefore, we sought to verify the effects of specific inhibition of FASN, through gene silencing techniques by short hairpin RNA (shRNA), on the area, perimeter, amount of mitochondria in autophagic vacuoles, as well as the integrity of mitochondrial cristae and processes of fission and fusion of this organelle in SCC-9 and LN-1A cells, derived from CCEO. Thus, we will discern and compare these mitochondrial morphological alterations, which reflect functional alterations resulting from TCS treatment of alterations caused by specific FASN inhibition, through transmission electron microscopy and image analysis.