The thyroid hormone/µ-crystalline axis is a key player in prostate cancer growth and a novel marker for prostate cancer progression in men
Osman Aksoy1,19, Jan Pencik1,2,19 Markus Hartenbach2,19, Ali Moazzami3, Michaela Schlederer1, Theresa Balber2, Martin Susani1, Elisa Redl1, Andrea Haitel1, Melanie Hassler4, Markus Mitterhauser2,5, Harald Esterbauer6, Rodrig Marculescu6, Georg Greiner6, Gero Kramer4, Pascal A. Baltzer7, Karin Schlangen8, Martin Schreiber9, Franz Quehenberger10, Tahereh Javaheri11,12, Dagmar Stoiber11,13, Jaqueline Horvath11,13, Sabrina Hartenbach14, Simone Roos15, Tim I. Malcolm16, Suzanne D. Turner16, Helmut H. Popper17, Gerda Egger1,5, Richard Moriggl11,12,13, Zoran Culig18 , Gregor Hoermann6, Marcus Hacker2, Olaf Merkel1,20,21 and Lukas Kenner1,11,15,20
1. Department of Pathology, Medical University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria 2. Department of Biomedical Imaging and Image guided Therapy, Division of Nuclear Medicine, Medical University Vienna, Vienna, Austria. 3. Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden. 4. Department of Urology, Medical University Vienna, Vienna, Austria. 5. Ludwig Boltzmann Institute Applied Diagnostics, Vienna, Austria. 6. Department of Laboratory Medicine, Medical University Vienna, Vienna, Austria. 7. Department of Biomedical Imaging and Image guided Therapy, Division of General and Pediatric Radiology, Medical University Vienna, Vienna, Austria. 8. Department of Biosimulation and Bioinformatics, Medical University Vienna, Vienna, Austria. 9. Department of Obstetrics & Gynecology, Medical University Vienna, Vienna, Austria. 10. Institute for Medical Informatics, Statistics and Documentation, Medical University Graz, Auenbruggerplatz 2, 8036 Graz, Austria. 11. Ludwig Boltzmann Institute for Cancer Research, Waehringerstrasse 13a, 1090 Vienna, Austria.12. Institute of Animal Breeding and Genetics, University of Veterinary Medicine Vienna. 13. Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria. 14. HistoConsulting Hartenbach, Ulm, Germany. 15. Unit of Pathology of Laboratory Animal Pathology, University of Veterinary Medicine, Veterinaerplatz 1,1210 Vienna, Austria. 16. Division of Cellular and Molecular Pathology, Department of Pathology, University of Cambridge, Lab Block Level 3, Box 231, Addenbrooke’s Hospital, Cambridge CB20QQ, United Kingdom. 17. Research Unit Molecular Lung and Pleura Pathology, Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, Graz, 8036, Austria. 18. Department of Urology, Innsbruck Medical University, Innsbruck, Austria
Key words: prostate cancer, PSA, TRß, µ-Crystallin, CRYM
Prostate cancer is the most often diagnosed malignant disease in men worldwide and millions of men are diagnosed with this disease each year. It has been well identified that androgens drive prostate tumorigenesis through androgen receptor signaling. In addition to androgens, thyroid hormones have been shown to regulate transcriptional regulation of multiple cancers. Triiodothyronine (T3), a hormone synthesized in the thyroid gland, acts through the interaction with nuclear receptors and binding proteins in cytosol such as μ- crystallin (CRYM). Cytosolic NADPH-dependent 3,5,3’-triiodo-L-thyronine is one of the thyroid hormone-binding component found in the cytoplasm. In this study, we inspected the role of CRYM in prostate cancer in response to thyroid hormone metabolic action. We evaluated CRYM and thyroid hormone receptor beta (TRβ1) expression levels in a panel ofprostate cancer Tissue microarray (TMA) containing patient samples from primary and metastatic sites by histopathological analyses and immunohistochemistry (IHC). CRYM was highly expressed in normal prostate tissues but the expression continuously decreased in primary and metastatic patient samples, whereas TRβ1 expression dramatically increased during disease progression. Low CRYM expression was associated with early biochemical recurrence and poor prognosis of patients. We used human prostate cell lines derived from metastases (LNCaP, PC3, DU145, 22RV-1 and LAPC4) and from non-transformed prostate epithelium (RWPE-1) to evaluate the protein expression of CRYM and TRβ1. RNA-seq analysis was performed using LNCaP CRYM over-expression and validated by RT-PCR. Intracellular T3 hormone-binding capacity increased in cells with high expression of cytosolic thyroid hormone-binding protein CRYM. Furthermore, CRYM led to the mitochondrial membrane potential (Δψ) depolarization in PCa cells being considered to release apoptotic enzymes to induce cell death. CRYM over-expression led to suppression of androgen- regulated target genes and intracellular choline metabolism. Non-invasive F18-methyl-choline (FMC) PET/MRI imaging of PCa patients correlated with TRβ1 and negatively with CRYM levels. Therefore, [18F]fluoromethylcholine (FMC) can be viewed as a novel predictive marker for PCa active surveillance. Inhibiton of thyroid hormone signaling resulted in decreasedgrowth and loss of tumor weight in xenografted PC3 in vivo. In conclusion, high expression of CRYM might inhibit the transcriptional regulatory effect of T3 by sequestering cytosolic T3 and reducing intracellular T3 levels. Thyroid hormone synthesis inhibitors might have a therapeutic relevance by deducing free T3/T4 levels that might slow down the disease progression and delay recurrence in patients with PCa.