Potential use of TIA-1, MFF, microRNA-200a-3p, and microRNA-27 as a novel marker for hepatocellular carcinoma.

Precise and early diagnosis is critical to improve the survival rate of hepatocellular carcinoma (HCC) patients. Although several genetic and protein markers have been developed and are currently used for diagnosis, prognosis, risk stratification, and therapeutic monitoring, application of these markers still needs to be improved for better specificity and efficacy. In this study, we investigated the relative expression of mitochondrial dynamics-regulating factors including T-cell intercellular antigen protein-1 (TIA-1), mitochondrial fission factor (MFF), microRNA (miR)-200a-3p, and miR-27a/b in the liver tissues from HCC patients. The expressions of TIA-1 and MFF were augmented in the cancerous liver tissues compared to the corresponding non-tumor tissues at mRNA and protein level, while the levels of miR-200a-3p and miR-27a/b were relatively lower in the cancerous liver tissues. In addition, high levels of TIA-1 and MFF mRNA were related to the poor survival rate of HCC patients. Our results indicated that the expressions of TIA-1, MFF, miR-200a-3p, and miR-27a/b in the cancerous liver tissues differed to these in non-cancerous tissues of HCC patients, demonstrating that these gene expressions could be potential markers for the diagnosis and prognosis of HCC.

Spectral and Hydrodynamic Analysis of West Nile Virus RNA-Protein Interactions by Multiwavelength Sedimentation Velocity in the Analytical Ultracentrifuge.

Interactions between nucleic acids and proteins are critical for many cellular processes, and their study is of utmost importance to many areas of biochemistry, cellular biology, and virology. Here, we introduce a new analytical method based on sedimentation velocity (SV) analytical ultracentrifugation, in combination with a novel multiwavelength detector to characterize such interactions. We identified the stoichiometry and molar mass of a complex formed during the interaction of a West Nile virus RNA stem loop structure with the human T cell-restricted intracellular antigen-1 related protein. SV has long been proven as a powerful technique for studying dynamic assembly processes under physiological conditions in solution. Here, we demonstrate, for the first time, how the new multiwavelength technology can be exploited to study protein-RNA interactions, and show how the spectral information derived from the new detector complements the traditional hydrodynamic information from analytical ultracentrifugation. Our method allows the protein and nucleic acid signals to be separated by spectral decomposition such that sedimentation information from each individual species, including any complexes, can be clearly identified based on their spectral signatures. The method presented here extends to any interacting system where the interaction partners are spectrally separable.

Tumor-promoting function and prognostic significance of the RNA-binding protein T-cell intracellular antigen-1 in esophageal squamous cell carcinoma.

T-cell intracellular antigen-1 (TIA1) is an RNA-binding protein involved in many regulatory aspects of mRNA metabolism. Here, we report previously unknown tumor-promoting activity of TIA1, which seems to be associated with its isoform-specific molecular distribution and regulation of a set of cancer-related transcripts, in esophageal squamous cell carcinoma (ESCC). Immunohistochemical overexpression of TIA1 ectopically localized in the cytoplasm of tumor cells was an independent prognosticator for worse overall survival in a cohort of 143 ESCC patients. Knockdown of TIA1 inhibited proliferation of ESCC cells. By exogenously introducing each of two major isoforms, TIA1a and TIA1b, only TIA1a, which was localized to both the nucleus and cytoplasm, promoted anchorage-dependent and anchorage-independent ESCC cell proliferation. Ribonucleoprotein immunoprecipitation, followed by microarray analysis or massive-parallel sequencing, identified a set of TIA1-binding mRNAs, including SKP2 and CCNA2. TIA1 increased SKP2 and CCNA2 protein levels through the suppression of mRNA decay and translational induction, respectively. Our findings uncover a novel oncogenic function of TIA1 in esophageal tumorigenesis, and implicate its use as a marker for prognostic evaluation and as a therapeutic target in ESCC.