Project description:T-cell intracellular antigen-1 (TIA1) is an RNA-binding protein modulating many regulatory aspects of target mRNA metabolism. Despite several reports referring to the role of TIA1 in carcinogenesis, little is known about the significance of its expression and function in human cancers including esophageal squamous cell carcinoma (ESCC). In the present study, we found that ectopic localization of overexpressed TIA1 in the cytoplasm was observed in a cohort of 143 ESCC patients using immunohistochemistry, and the cytoplasmic TIA1 was an independent prognosticator for worse overall survival. Moreover, we revealed that TIA1 was overexpression in many ESCC cell lines, and silencing of TIA1 in those cells inhibited cell growth with an accumulation of cells in G0âG1 and sub-G1 phases. The human TIA1 gene generates two major protein isoforms, TIA1a and TIA1b. Expression of TIA1a isoform tended to be higher than that of TIA1b in ESCC cells, and TIA1a was expressed both in the nucleus and cytoplasm but TIA1b was expressed mainly in the nucleus. Further studies revealed that each isoform showed opposite effects on cell proliferation through ectopically introducing each gene: TIA1a promotes anchorage-dependent and independent cell proliferation, whereas TIA1b inhibits cell proliferation and/or induces cell death. The ribonucleoprotein immunoprecipitation followed by a microarray analysis or massive-parallel sequencing identified a set of TIA1-associating mRNAs including enriched cell cycle-associated genes. Among them, SKP2 and CCNA2 mRNA were shown to be interacted with TIA1 protein through their different regions, and SKP2 and CCNA2 protein levels were positively regulated by TIA1 through suppression of mRNA decay and translational induction, respectively. These findings provide new insights into the previously unknown role of TIA1 and its isoforms as tumor-promoting molecules regulating a set of downstream oncogenic proteins, and implicate their potential application as a useful marker of malignant potential and a therapeutic target in ESCC. To investigate the target molecules regulated by TIA1 in esophageal squamous cell carcinoma cell line (KYSE180), the expression levels of mRNAs (total) and transcripts captured by RIP with TIA1 antibody (TIA1_RIP) were analyzed using microarray.

Project description:T-cell intracellular antigen-1 (TIA1) is an RNA-binding protein modulating many regulatory aspects of target mRNA metabolism. Despite several reports referring to the role of TIA1 in carcinogenesis, little is known about the significance of its expression and function in human cancers including esophageal squamous cell carcinoma (ESCC). In the present study, we found that ectopic localization of overexpressed TIA1 in the cytoplasm was observed in a cohort of 143 ESCC patients using immunohistochemistry, and the cytoplasmic TIA1 was an independent prognosticator for worse overall survival. Moreover, we revealed that TIA1 was overexpression in many ESCC cell lines, and silencing of TIA1 in those cells inhibited cell growth with an accumulation of cells in G0–G1 and sub-G1 phases. The human TIA1 gene generates two major protein isoforms, TIA1a and TIA1b. Expression of TIA1a isoform tended to be higher than that of TIA1b in ESCC cells, and TIA1a was expressed both in the nucleus and cytoplasm but TIA1b was expressed mainly in the nucleus. Further studies revealed that each isoform showed opposite effects on cell proliferation through ectopically introducing each gene: TIA1a promotes anchorage-dependent and independent cell proliferation, whereas TIA1b inhibits cell proliferation and/or induces cell death. The ribonucleoprotein immunoprecipitation followed by a microarray analysis or massive-parallel sequencing identified a set of TIA1-associating mRNAs including enriched cell cycle-associated genes. Among them, SKP2 and CCNA2 mRNA were shown to be interacted with TIA1 protein through their different regions, and SKP2 and CCNA2 protein levels were positively regulated by TIA1 through suppression of mRNA decay and translational induction, respectively. These findings provide new insights into the previously unknown role of TIA1 and its isoforms as tumor-promoting molecules regulating a set of downstream oncogenic proteins, and implicate their potential application as a useful marker of malignant potential and a therapeutic target in ESCC.

Project description:Objective: Globally, esophageal cancer is among the most deadly cancer forms. Long non-coding RNAs (lncRNA) are frequently found to have important regulatory roles. We aim to assess the lncRNA expression profile of esophageal squamous cell carcinoma (ESCC) and identify prognosis related lncRNAs. Design: LncRNA expression profiles were studied by microarray in paired tumor and normal tissues from 119 ESCC patients, and validated by qRT-PCR. The 119 patients were subsequently divided randomly into training (n=60) and test (n=59) groups. A prognostic signature was developed from the training group using a random forest supervised classification algorithm and a nearest shrunken centroid algorithm, and validated in test group and further in an independent cohort (n=60). The independence of the signature in survival prediction was evaluated by Multivariable Cox regression analysis. Results: LncRNAs showed significantly altered expression in ESCC tissues. From the training group, we identified a three-lncRNA signature (including the lncRNAs ENST00000435885•1, XLOC_013014, and ENST00000547963•1) which classified the patients into two groups with significantly different overall survival (median survival 19•2 months vs. not reached, p<0•0001). The signature was applied to the test group (median survival 21•5 months vs. not reached, p=0•0030) and independent cohort (median survival 25•8 months vs. not reached, p=0•0187) and showed similar prognostic values in both. Multivariable Cox regression analysis showed that the signature was an independent prognostic factor for ESCC patients. Stratified analysis suggested that the signature was prognostic within clinical stages. Conclusions: Our results suggest that the three-lncRNA signature can serve as a novel biomarker for the prognosis of ESCC patients. Application of it allows for more accurate survival prediction. The lncRNA expression profiles of cancer and adjacent normal tissues form 119 ESCC patients were studied by microarray and an lncRNA signature that can perdict the survival of ESCC patients was identified.

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Homo sapiens

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