Abstract. miRNA profile deregulation affecting downstream signaling pathways activates endpoints that represent potential biomarkers for prognosis and treatment of tumor patients. In the past 20 years conventional therapy for osteosarcoma (OS) reached a survival plateau, highlighting the need for new therapeutic approaches. In this study, microarray unsupervised and supervised analysis identified, respectively, 100 and 40 differentially expressed miRNAs in OS samples with different grades of malignancy compared to normal bone. When analyzing low-grade and high-grade OS by unsupervised analysis, 12 miRNAs were found to be differentially expressed. Real-time PCR performed on a larger series of OS confirmed a significant lower expression of miR-1, miR-133b and miR-378 * in tumors with respect to control, also showing lower mRNA levels in 31 high-grade OS than in 25 low-grade and in metastatic versus non-metastatic patients. We demonstrated that miR-1 and miR133b were downregulated in OS cell lines compared to normal osteoblasts. Secondly, by transfection with miRNA precursor molecules, we demonstrated that the ectopic expression of miR-1 and miR-133b in U2-OS cell lines significantly reduced cell proliferation and MET protein expression and negatively regulated cell invasiveness and motility in a short-term assay. Cell cycle distribution revealed block in G 1 and delay of cell cycle progression associated with increased apoptosis in miR-1-and miR-133b-transfected cells, respectively. Our data assessed specific miRNA profiling deregulation in OS clinical samples and suggest that the expression of miR-1 and miR-133b may control cell proliferation and cell cycle through MET protein expression modulation. IntroductionOsteosarcoma (OS) is a rare malignant bone neoplasm for which biologic and pathologic information are still largely incomplete. OS has multiple genetic risk factors (1) and is characterized by complex chromosomal abnormalities and genetic cell heterogeneity that in over 70% provide a complex karyotype and drug resistance (2). MicroRNAs (miRNAs) are endogenous non-coding RNAs of 19-24 nucleotides that interacting with the 3' untranslated region (UTR) of mRNA target induce mRNA cleavage when pairing is complete and protein synthesis repression when pairing is incomplete. The relationship between miRNAs and their targets shows combinatorial complication, in terms of both target multiplicity and signal integration (3). MiRNAs are differentially expressed in relation to the developmental state, cell type and tissue (4-6). In literature, there are approximately 1,000 miRNA molecules per cell, with some cells exceeding 50,000 molecules (7). miRNA expression follows a dynamic range and this underscores the regulatory functional importance of miRNAs (3). Recent studies indicate that miRNAs called 'oncomirs' can function either as tumor suppressors or as oncogenes (8).Interconnection between miRNA and cancer is even more evident when analyzing the genomic location of known miRNA genes, more than 50% are in cancer-as...

Our genetic studies highlight the heightened vulnerability of liver cells to subtle changes in nononcogenic RTK levels, allowing them to acquire a molecular profile that facilitates the full tumorigenic program; furthermore, our outcomes uncover new synthetic lethal interactions as potential therapies for a cluster of HCC patients. (Hepatology 2017;66:1644-1661).

The rare and highly aggressive adult soft tissue sarcomas leiomyosarcoma (LMS) and undifferentiated pleomorphic sarcoma (UPS) contain complex genomes characterized by a multitude of rearrangements, amplifications, and deletions. Differential diagnosis remains a challenge. MicroRNA (miRNA) profiling was conducted on a series of LMS and UPS samples to initially investigate the differential expression and to identify specific signatures useful for improving the differential diagnosis. Initially, 10 high-grade LMS and 10 high-grade UPS were profiled with a miRNA microarray. Two cultured human mesenchymal stem cell samples were used as controls. 38 and 46 miRNAs classified UPS and LMS samples, respectively, into separate groups compared to control samples. When comparing the two profiles, miR-199b-5p, miR-320a, miR-199a-3p, miR-126, miR-22 were differentially expressed. These were validated by RT-PCR on a further series of 27 UPS and 21 LMS for a total of 68 cases. The levels of miR-199-5p and miR-320a, in particular, confirmed the microarray data, the former highly expressed in UPS and the latter in LMS. Immunohistochemistry was performed on all 68 cases to confirm original diagnosis. Recently reported LMS- and UPS-associated genes were correlated with miRNA targets based on target algorithms of three databases. Several genes including IMP3, ROR2, MDM2, CDK4, and UPA, are targets of differentially expressed miRNAs. We identified miRNA expression patterns in LMS and UPS, linking them to chromosomal regions and mRNA targets known to be involved in tumor development/progression of LMS and UPS.

Although further studies are needed to evaluate miRNA involvement in osteosarcoma progression, miR-93 overexpression seems to play an important role in osteosarcoma cell growth and invasion.

Hepatocellular carcinoma (HCC) represents the fifth and ninth cause of mortality among male and female cancer patients, respectively and typically arises on a background of a cirrhotic liver. HCC develops in a multi-step process, often encompassing chronic liver injury, steatosis and cirrhosis eventually leading to the malignant transformation of hepatocytes. Aberrant expression of the class I homeobox gene family (HOX), a group of genes crucial in embryogenesis, has been reported in a variety of malignancies including solid tumors. Among HOX genes, HOXA13 is most overexpressed in HCC and is known to be directly regulated by the long non-coding RNA HOTTIP. In this study, taking advantage of a tissue microarray containing 305 tissue specimens, we found that HOXA13 protein expression increased monotonically from normal liver to cirrhotic liver to HCC and that HOXA13-positive HCCs were preferentially poorly differentiated and had fewer E-cadherin-positive cells. In two independent cohorts, patients with HOXA13-positive HCC had worse overall survival than those with HOXA13-negative HCC. Using HOXA13 immunohistochemistry and HOTTIP RNA in situ hybridization on consecutive sections of 16 resected HCCs, we demonstrated that HOXA13 and HOTTIP were expressed in the same neoplastic hepatocyte populations. Stable overexpression of HOXA13 in liver cancer cell lines resulted in increased colony formation on soft agar and migration potential as well as reduced sensitivity to sorafenib in vitro. Our results provide compelling evidence of a role for HOXA13 in HCC development and highlight for the first time its ability to modulate response to sorafenib.