Abstract 1251: Novel potential role of m6A-demethylase FTO (fat mass and obesity) protein in colorectal cancer

Colorectal cancer (CRC) is the one of the most frequent and deadly cancer worldwide. The regulation mediated by the N6methyladenosine (m6A) demethylase protein called FTO in CRC is quite controversial. As previously studied in obesity and food intake, currently is being linked to stemness, epithelial-mesenchymal transition, chemotherapy resistance and proliferation in colon cancer cells, however, its localization and function in the tumor microenvironment (TME) and how it connects with progression remains unclear. The aim of this study was to evaluate FTO protein in tumor and healthy corresponding tissue from 22 colorectal cancer patients with different histological TNM stages (hTNM) by immunohistochemistry and multiple immunofluorescence analysis; classifying the tumor and stromal FTO localization and associating this data with clinical and histopathological features. As for content, the frequency of FTO+ cells in stromal compartments increases in more invasive stages compared to non-tumor tissue and in tumors with low desmoplasia. Regarding to localization, FTO is mostly nuclear and present in the lamina propria cells in non-tumor tissues and in immune and fibro-immune compartments in the TME, such as T cells, cancer associated fibroblasts and macrophages. In tumor cells, the percentage of FTO+ cells increase in early carcinogenic stages (hTNM I vs healthy tissue) and in moderately differentiated tumors. In addition, nuclear FTO expression increases in normal T cells and fibroblasts with a particular pattern after exposure for 24h to a colon adenocarcinoma cell-derived conditioned media, suggesting FTO activity in the TME interaction following a paracrine signal. In conclusion, the increase of the FTO protein in both tumor and stroma from CRC suggests its participation mediating TME communication.

Citation Format: Glauben T. Landskron-Ramos, Antonia L. Domínguez-Beltrando, Mauricio Zambra-Rojas, Antonella Sanguineti, Gonzalo Vasquez, Marjorie De la Fuente, Daniela Simian, Silvana Valdebenito-Silva, Juan Saavedra, Solange Gouet, Ricardo Soto-Rifo, Daniela Sauma, Eliseo Eugenin, Mario Abedrapo, Marcela A. Hermoso, Marcela A. Hermoso. Novel potential role of m6A-demethylase FTO (fat mass and obesity) protein in colorectal cancer [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 1251.

Fluconazole-resistant Candida albicans after long-term suppressive therapy

Candida albicans is generally considered to be susceptible, in vivo, to fluconazole. In the population infected with human immunodeficiency virus, recurrent bouts of oral and esophageal candidiasis have led to increasing use of fluconazole for long-term prophylaxis. With prolonged therapy, the issue of developing resistance emerges. We report a case of fluconazole-resistant C albicans esophagitis that developed after fluconazole was used for more than 600 days.

Cell adhesion to silicon substrata: characterization by means of optical and acoustic cytometric techniques

The adhesion and growth of cells on silicon dioxide substrata are analysed. The adhesion of human red blood cells to silicon dioxide layers of different depth and doping compares well with that to glass. Rat pheochromocytoma cells also grow on the same substrata. The adhesion of these two biological systems is characterized at the microscopic level by using the quite new technique of scanning reflection acoustic microscopy. Possible future developments towards the functional coupling of living cells to microelectronic integrated circuits are briefly discussed.