Abstract 2855: Epithelial-mesenchymal transition profile after cisplatin-resistance induction in OSCC cell line
Authors: De Lima Dieila Giomo , Borgato Gabriell Bonifácio , Guimarães Gustavo Narvaes , Bastos Débora Campanella , Coletta Ricardo Della , De Souza Ana Paula 
Published: June 2023

Abstract
Oral cancer is among the most common types of cancer in humans. Chemotherapy, mainly based on cisplatin, is utilized in the treatment of advanced cases. However, a loss of chemotherapy effectiveness is frequent and can be related to both inherent or acquired resistance to the chemotherapy agent, resulting in high relapse rates. Epithelial-mesenchymal transition (EMT) plays an important role in different stages of cancer, and it is correlated to resistance to therapy, but the process is still unclear. The purpose of this study is to explore EMT markers in a cisplatin resistant-based model. After determination of IC50, SCC9 cells were intermittently exposed to stepwise increasing concentrations of cisplatin, and Resistance Index (RI) was calculated. Population Doubling (PD) and Population Doubling Time (PDT) were calculated counting the number of viable cells using Trypan Blue method. Scratch assay was performed to investigate the impact on cellular migration. EMT-correlated markers were accessed by RT-qPCR and western blot. After 4 intermittent exposures to cisplatin, we obtained different clones with cisplatin resistance level, SCC9/CPR5 (intermediate cisplatin resistance) and SCC9/CPR11 (final cisplatin resistance) the SCC9/CPR5 clone was obtained showing a mixed morphology between polygonal and fusiform. The complete fusiform morphology resembling mesenchymal cells was seen in SCC9/CPR11, which demonstrated 2-fold of cisplatin resistance in comparison to parental cell line. SCC9/CPR11 showed a difference of less than 1.16 PD and more than 15.5 hours PDT in relation to SCC9. Interestingly, the migratory profile was increased in SCC9/CPR5. Snail1 and Vimentin mRNA levels and protein expression were increased at SCC9/CPR11, but surprisingly E-cadherin was overexpressed but not in protein level. Others markers such as Zeb1, N-cadherin, Vimentin, Snail2 and Twist showed an increase in mRNA levels only in SCC-9-CPR11, however only Twist exhibited high protein expression. Our study showed the establishment of cisplatin resistant SCC9 cells in different moments in relation to a resistance level based on the main two protein markers of EMT, Snail1 and Vimentin. Our data need to be further validated in larger well characterized techniques and we further envision investigating the epigenetic in DNA damage pathways correlating with cisplatin resistance and EMT status.
Citation Format: Dieila Giomo De Lima, Gabriell Bonifácio Borgato, Gustavo Narvaes Guimarães, Débora Campanella Bastos, Ricardo Della Coletta, Ana Paula De Souza. Epithelial-mesenchymal transition profile after cisplatin-resistance induction in OSCC cell line [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2855.