Although one of the first comprehensive examinations of long non-coding RNA (lncRNA) expression was performed in human CD8 T lymphocytes, little is known about their roles in CD8 T cells functions during the progression of hepatocellular carcinoma (HCC). Here, we show that Lnc-Tim3 is upregulated and negatively correlates with IFN-γ and IL-2 production in tumor-infiltrating CD8 T cells of HCC patients. Lnc-Tim3 plays a pivotal role in stimulating CD8 T exhaustion and the survival of the exhausted CD8 T cells. Mechanistically, Lnc-Tim3 specifically binds to Tim-3 and blocks its interaction with Bat3, thus suppressing downstream Lck/ NFAT1/AP-1 signaling, leading to nuclear localization of Bat3, and enhancing p300-dependent p53 and RelA transcriptional activation of anti-apoptosis genes including MDM2 and Bcl-2. In summary, Lnc-Tim3 promotes T cell exhaustion, a phenotype which is correlated with compromised anti-tumor immunity, suggesting that Lnc-Tim3 and its associated signaling pathways may influence the outcome of cancer therapies aimed at modulating the acquired immune system.

Background/Aims: Long non-coding RNAs (lncRNAs) have been reported to play pivotal roles in multiple tumors and can act as tumor biomarkers. In this study, we explored the association of the expression of an lncRNA, DGCR5 with clinicopathological features and prognosis in HCC. Methods: Expression levels of DGCR5 were detected by quantitative real-time PCR (qRT-PCR) and the clinical data was obtained, including basic information, data of clinicopathology and cancer specific survival rate. Receiver operating characteristic (ROC) curve, Kaplan-Meier methods and multivariable Cox regression models were used to analyze predictive efficiency, long-term survival outcomes and risk factors. Results: DGCR5 was found down-regulated in HCC tissues (P<0.001) and serum (P = 0.0035) and low expression of DGCR5 was correlated with a poor cancer specific survival (CSS) (P = 0.0019), as the overall 5-year CSS rates were 10.3% (low expression group) and 36.6% (high expression group), respectively. A stratified analysis demonstrated that low DGCR5 expression was an independent negative prognostic factor for HCC. In addition, the area under the ROC curve was 0.782 with a sensitivity of 0.633 and a specificity of 0.833. Conclusions: Our results suggest that DGCR5 may be a participator in HCC and can serve as potential biomarker for the diagnosis and prognosis in HCC.

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Cluster of differentiation 97 (CD97) is a member of the epidermal growth factor seven-transmembrane family belonging to the class B G protein-coupled receptors (GPCRs). The protein affects tumor aggressiveness through its cellular ligand CD55 stimulation and exhibits adhesive properties. Studies have demonstrated the involvement of CD97 in dedifferentiation, migration, invasiveness, and metastasis of tumors. However, little information is currently available on the specific role of CD97 in hepatocellular carcinoma (HCC). Here, we have shown that CD97 up-regulation in HCCs is positively correlated with tumor metastasis. Functionally, CD97 promoted cell migration and invasion in vitro. In an in vivo mouse model, overexpression of CD97 in HCC cells led to accelerated lung metastasis. Mechanistically, CD97 cooperated with the altered regulator, GPCR kinase 6 (GRK6), to mediate GPCR desensitization and internalization. Down-regulation of GRK6 suppressed CD97 internalization and promoted CD97 expression. Integrated regulatory interactions between CD97 and GRK6 stimulated downstream matrix metalloproteinase 2/9 secretion and, consequently, HCC metastasis. Conclusion: Our collective findings support the utility of CD97 as an effective potential prognosticator and therapeutic target for HCC.

The retinoblastoma gene (RB1), a known tumor-suppressor gene (TSG), was decreased in multiple cancers including hepatocellular carcinoma (HCC). Here we focused on the bidirectional transcripted long noncoding RNA (Linc00441) with neighbor gene RB1 to investigate whether Linc00441 is involved in the suppression of RB1 in HCC. We found that aberrant upregulated intranuclear Linc00441 was reversely correlated with RB1 expression in human HCC samples. The gain- and loss-of-function investigation revealed that Linc00441 could promote the proliferation of HCC cells in vitro and in vivo with an apoptosis suppression and cell cycle rearrangement. Furthermore, RNA pull-down assay indicated the decreased level of RB1 induced by Linc00441 was associated with the incidental methylation by DNMT3A recruited by Linc00441. On the contrary, the transcription factor (TCF-4) enhanced H3K27 acetylation and direct transcription factor for Linc00441 was responsible for the upregulation of Linc00441 in HCC. In conclusion, the epigenetic interaction between Linc00441 and bidirectional transcripted neighbor RB1 may be a de novo theory cutting-point for the inactivation of RB1 in HCC and may serve as targeting site for tumor therapy in the future.

Background and Aims Liver cancer stem cells (CSCs) exist in the tumor environment and are critically involved in the initiation and progression of hepatocellular carcinoma (HCC). However, the underlying molecular mechanisms of self‐renewal and maintenance of liver CSCs remain poorly understood. Approach and Results We identified that xanthine oxidoreductase (XOR), which was expressed at low levels in human HCC samples and liver CSCs, restrained HCC formation and chemoresistance by attenuating liver CSC propagation. Mechanistically, XOR physically interacts with ubiquitin‐specific peptidase 15 (USP15), thereby promoting deubiquitination of Kelch‐like ECH associated protein 1 (KEAP1) to stabilize its expression, which leads to degradation of Nrf2 (nuclear factor erythroid 2–related factor 2) through ubiquitination and subsequently reactive oxygen species accumulation in liver CSCs. Finally, our data reveal that XOR promotes USP15‐mediated Nrf2‐KEAP1 signaling to block liver CSCs and tumor propagation. Conclusion We identified that XOR may represent a potential therapeutic target for clinical intervention in HCC driven by liver CSCs.

Hepatocellular carcinoma (HCC) is the most prevalent subtype of liver cancer, and it is characterized by high rate of metastasis and recurrence. Recent studies have boosted our understanding that Gankyrin contributes to both of these pathological properties, but the mechanisms underlying its aberrant regulation are poorly understood. Recently, many long noncoding RNAs (lncRNAs) have been reported to be involved in regulating the expression of oncogenes and anti-oncogenes through various mechanisms. Here, using transcriptome microarray analysis, we identified a long intergenic noncoding RNA termed Linc-GALH that was highly expressed and concordance with Gankyrin expression in HCC. In addition, we revealed that Linc-GALH was an independent unfavorable prognostic indicator for HCC, followed functional experiments showed that Linc-GALH promoted HCC cells migration and invasion in vitro, and enhanced lung metastasis ability of HCC cells in vivo. Mechanistically, we found that Linc-GALH could regulate the expression of Gankyrin through controlling the methylation status of Gankyrin by adjusting the ubiquitination status of DNMT1 in HCC. Collectively, our results demonstrated the role and functional mechanism of Linc-GALH in HCC, and indicated that Linc-GALH may act as a prognostic biomarker and potential therapeutic target for HCC.