o:25317 Focal adhesion kinase splicing and protein activation in papillary thyroid carcinoma progression Splajs varijante fokalne adhezione kinaze i proteinska aktivacija u progresiji papilarnog karcinoma štitaste žlezde en ABSTRACT Papillary thyroid carcinoma (PTC), a common endocrine malignancy, presents a challenge from a prognostic standpoint. Molecular alterations underlying PTC progression include deregulation of focal adhesion kinase (FAK) at post-transcriptional and post-translational levels. Searching for candidate markers of PTC progression, we investigated the prognostic significance of FAK alterations on mRNA/protein level. The expression levels and subcellular localisation of auto-phosphorylated FAK (pY397-FAK) were determined by western blot (WB) and immunohistochemistry. The quantity of total FAK mRNA, alternatively spliced FAK-Del26 and FAK-Del33 variants were analysed by RT-qPCR and related to pY397-FAK expression and subcellular distribution. The results were correlated with clinicopathological parameters of the patients. The expression of pY397-FAK was significantly elevated in malignant samples. Active FAK showed predominant cytoplasmic distribution with co-occurrence along the membrane, while nuclear staining was found less frequently. Expression of pY397-FAK in separate cellular compartments correlated with adverse clinicopathological parameters, but the strongest association was found when their mean scores were calculated. Alternatively spliced FAK-Del33 and total FAK transcripts positively correlated to pY397-FAK protein levels as well as to characteristics of PTC advancement. Over-expression of FAK on mRNA (total and Del-33) and activated protein (pY397-FAK) levels is a feature of PTC advanced stages. Of the analysed alterations, the mean pY397-FAK IHC score showed the best predictive performance. Correlation between mRNA FAK-Del33 and pY397-FAK expression implies a regulatory role of alternative splicing in PTC patients. Sažetak alternative splicing, focal adhesion kinase, papillary thyroid carcinoma, tumour prognostic factors, pY397-FAK 1552099 10.1007/s00418-021-02056-y 2022-05-12T12:44:29.925Z 44 yes 46 Valentina Ignjatović University of Belgrade, Institute for the Application of Nuclear Energy INEP, Serbia 0000-0002-9887-4237 Jelena Janković Miljuš University of Belgrade, Institute for the Application of Nuclear Energy INEP, Serbia doktor biohemijskih nauka person 0000-0002-2589-3306 Jelena Rončević University of Belgrade, Institute for the Application of Nuclear Energy INEP, Serbia person 0000-0003-3656-6420 Svetislav Tatić University of Belgrade, Faculty of Medicine, Insitute of Pathology, Serbia person Tijana Išić Denčić University of Belgrade, Institute for the Application of Nuclear Energy INEP, Serbia doktor bioloških nauka person 0000-0001-8475-2266 Ilona Đorić University of Belgrade, Institute for the Application of Nuclear Energy INEP, Serbia doktor bioloških nauka person 0000-0001-5322-4559 Sonja Šelemetjev University of Belgrade, Institute for the Application of Nuclear Energy INEP, Serbia doktor bioloških nauka person 0000-0002-2898-6671 application/pdf 6831 https://phaidrabg.bg.ac.rs/o:25317 no yes 1 70 92000001 11A29 11A2902 11A32 11A3240 Histochemistry and cell biology 157 2 183 194 Springer 2021