1. Department of Traumatology and Orthopedics, University of Tartu, Estonia.
2. Traumatology and Orthopaedics Clinic, Tartu University Hospital, Tartu, Estonia.
4. Department of Pathology, Tartu University Hospital, Tartu, Estonia.
Osteosarcoma (OS) is primary malignant bone tumour with complicated early diagnosis. There are no specific markers currently available for predicting the prognosis and chemosensitivity of OS. In present study we performed transcriptome profiling of single patient tumour tissue with RNA-seq technology. We analysed surgically removed sarcoma sample from single 16 years old male patient. Transciptome analysis was done with RNA-seq technology, bioinformatics with Lifescope and R Bioconductor. Validation experiments were done with quantitative real-time PCR (QRTPCR). After quality and coverage filtering, RNA-seq experiment resulted 29,311,899 mapped reads for sarcoma and 22,099,159 mapped reads for normal bone tissue. 65 genes were differentially expressed with FDR corrected statistical significance below 0.05. Seven genes were down-regulated and 58 genes were up-regulated in sarcoma. The most highly up-regulated gene in sarcoma was adiponectin, ADIPOQ (with adjusted p-value 5.5E-07, log2 fold change was 7.9). Many of the genes we found are related to the adipose tissue metabolism (ADIPOQ, PLIN1, FABP4) and to the Wnt signalling suppression (WIF1, SOST). We also found novel fusion transcript between the genes LMTK2 and ZSWIM5. LMTK2 is lemur tyrosine kinase 2, and it has been shown to be involved in NGF-TrkA signalling. Interestingly, studies support the involvement of LMTK2 in development of prostate cancer. ZSWIM5 is zinc finger SWIM domain protein 5 and its function is not known. Immunohistochemical analysis confirmed positive staining for adiponectin in osteosarcoma. This paper is a good illustration how transcriptome analysis can find new biomarkers and targets for complex diseases.
Keywords: Osteosarcoma, transcriptome, adiponectin, WIF1