Regulation of habenular G-protein gamma 8 on learning and memory via modulation of the central acetylcholine system.

Guanine nucleotide binding protein (G protein) gamma 8 (Gng8) is a subunit of G proteins and expressed in the medial habenula (MHb) and interpeduncular nucleus (IPN). Recent studies have demonstrated that Gng8 is involved in brain development; however, the roles of Gng8 on cognitive function have not yet been addressed. In the present study, we investigated the expression of Gng8 in the brain and found that Gng8 was predominantly expressed in the MHb-IPN circuit of the mouse brain. We generated Gng8 knockout (KO) mice by CRISPR/Cas9 system in order to assess the role of Gng8 on cognitive function. Gng8 KO mice exhibited deficiency in learning and memory in passive avoidance and Morris water maze tests. In addition, Gng8 KO mice significantly reduced long-term potentiation (LTP) in the hippocampus compared to that of wild-type (WT) mice. Furthermore, we observed that levels of acetylcholine (ACh) and choline acetyltransferase (ChAT) in the MHb and IPN of Gng8 KO mice were significantly decreased, compared to WT mice. The administration of nAChR α4ß2 agonist A85380 rescued memory impairment in the Gng8 KO mice, suggesting that Gng8 regulates cognitive function via modulation of cholinergic activity. Taken together, Gng8 is a potential therapeutic target for memory-related diseases and/or neurodevelopmental diseases.

Peroxiredoxin II Is Essential for Maintaining Stemness by Redox Regulation in Liver Cancer Cells.

Redox regulation in cancer stem cells (CSCs) is viewed as a good target for cancer therapy because redox status plays an important role in cancer stem-cell maintenance. Here, we investigated the role of Peroxiredoxin II (Prx II), an antioxidant enzyme, in association with maintenance of liver CSCs. Our study demonstrates that Prx II overexpressed in liver cancer cells has high potential for self-renewal activity. Prx II expression significantly corelated with expression of epithelial-cell adhesion molecules (EpCAM) and cytokerain 19 in liver cancer tissues of hepatocellular carcinoma (HCC) patients. Downregulation of Prx II in Huh7 cells with treatment of siRNA reduced expression of EpCAM and CD133 as well as Sox2 in accordance with increased ROS and apoptosis, which were reversed in Huh7-hPrx II cells. Huh7-hPrx II cells exhibited strong sphere-formation activity compared with mock cells. Vascular endothelial growth factor (VEGF) exposure enhanced sphere formation, cell-surface expression of EpCAM and CD133, and pSTAT3 along with activation of VEGF receptor 2 in Huh7-hPrx II cells. The result also emerged in Huh7-H-ras(G12V) and SK-HEP-1-H-ras(G12V) cells with high-level expression of Prx II. Prx II was involved in regulation of VEGF driving cancer stem cells through VEGFR-2/STAT3 signaling to upregulate Bmi1 and Sox2. In addition, knockdown of Prx II in Huh7-H-ras(G12V) cells showed significant reduction in cell migration in vitro and in tumorigenic potential in vivo. Taken together, all the results demonstrated that Prx II plays a key role in the CSC self-renewal of HCC cells through redox regulation. Stem Cells 2016;34:1188-1197.

Hepatitis B virus X promotes hepatocellular carcinoma development via nuclear protein 1 pathway.

Hepatocellular carcinoma (HCC) is one of the most common malignancies and chronic hepatitis B virus (HBV) infection is a major risk factor for HCC. Hepatitis B virus X (HBx) protein relates to trigger oncogenesis. HBx has oncogenic properties with a hyperproliferative response to HCC. Nuclear protein 1 (NUPR1) is a stress-response protein, frequently upregulated in several cancers. Recent data revealed that NUPR1 is involved in tumor progression, but its function in HCC is not revealed yet. Here we report HBx can induce NUPR1 in patients, mice, and HCC cell lines. In an HBx transgenic mouse model, we found that HBx overexpression upregulates NUPR1 expression consistently with tumor progression. Further, in cultured HBV positive cells, HBx knockdown induces downregulation of NUPR1. Smad4 is a representative transcription factor, regulated by HBx, and we showed that HBx upregulates NUPR1 by Smad4 dependent way. We found that NUPR1 can inhibit cell death and induce vasculogenic mimicry in HCC cell lines. Moreover, NUPR1 silencing in HepG2-HBx showed reduced cell motility. These results suggest that HBx can modulate NUPR1 expression through the Smad4 pathway and NUPR1 has a role in hepatocellular carcinoma progression.

In vivo genome editing using the Cpf1 ortholog derived from Eubacterium eligens.

Cpf1 is an RNA-guided endonuclease that can be programmed to cleave DNA targets. Specific features, such as containing a short crRNA, creating a staggered cleavage pattern and having a low off-target rate, render Cpf1 a promising gene-editing tool. Here, we present a new Cpf1 ortholog, EeCpf1, as a genome-editing tool; this ortholog is derived from the gut bacterial species Eubacterium eligens. EeCpf1 exhibits a higher cleavage activity with the Mn2+ metal cofactor and efficiently cuts the target DNA with an engineered, nucleotide extended crRNA at the 5' target site. When mouse blastocysts were injected with multitargeting crRNAs against the IL2R-γ gene, an essential gene for immunodeficient mouse model production, EeCpf1 efficiently generated IL2R-γ knockout mice. For the first time, these results demonstrate that EeCpf1 can be used as an in vivo gene-editing tool for the production of knockout mice. The utilization of engineered crRNA with multiple target sites will help to explore the in vivo DNA cleavage activities of Cpf1 orthologs from other species that have not been demonstrated.

IGF-II induced by hepatitis B virus X protein regulates EMT via SUMO mediated loss of E-cadherin in mice.

Hepatocellular carcinoma (HCC) is one of the most common cancers and a leading cause of cancer mortality. Prognosis of this disease largely depends on its stage. An Enlarged liver, due to dysplasia, may be a critical point in the multi-step progression to HCC. The mechanism underlying hepatomegaly in human and mouse models are poorly understood. We previously reported we observed enlarged liver in hepatitis B virus X protein (HBx) expressing mice (HBx mice). Here we identify the critical role of HBx induced IGF-II in hepatomegaly in mice and abnormal cell growth in human hepatoma cells. We found that HBx induced IGF-II is essential to induce epithelial-mesenchymal transition (EMT) through loss of E-cadherin. In mouse liver, loss of E-cadherin was mediated by post-translational regulation, at least in part, by protease and SUMOylation not by transcriptional regulation. In contrast, in hepatoma cell line (HepG2 cells) Akt signal pathway controls the mRNA expression level of EMT-related transcription factors, especially Twist, in addition to post- translational modification through SUMOylation. Thus, IGF-II-mediated loss of E-cadherin is central in developing hepatomegaly in mice and abnormal cell growth in the hepatoma cell line. HBx induced IGF-II represents a potential biomarker, which is also a therapeutic target in HCC.

IL-32θ inhibits stemness and epithelial-mesenchymal transition of cancer stem cells via the STAT3 pathway in colon cancer.

Interleukin (IL)-32 is a well-known cytokine associated with inflammation, virus infections and cancer. IL-32θ is a newly identified isoform of IL-32, whose function has yet to be elucidated. In this study, we investigated IL-32θ function in colon cancer stem cells. Using samples from colon cancer patients, we found that the expression of IL-32θ mRNAs was significantly suppressed in tumor regions. We investigated the effects of IL-32θ on colon cancer. Ectopic expression of IL-32θ attenuated invasion, migration in vitro and in vivo tumorigenicity of colon cancer cells. IL-32θ inhibited epithelial-mesenchymal transition (EMT), resulting in the suppression of their migratory and invasive capabilities of HT29 colon cancer cells. In addition, IL-32θ altered various properties of CSCs, including sphere formation and expression of stemness related genes. IL-32θ directly bound to STAT3 and inhibited its nuclear translocation, leading to inhibited transcription of downstream factors, including Bmi1 and ZEB1. We showed that IL-32θ inhibited the STAT3-ZEB1 pathway and consequently inhibited key factors of stemness and EMT. Taken together, our findings reveal that IL-32θ can be a tumor suppressor, indicating that IL-32θ could possibly be used in therapies for colon cancer.

Peroxiredoxin I is important for cancer-cell survival in Ras-induced hepatic tumorigenesis.

Peroxiredoxin I (Prx I), an antioxidant enzyme, has multiple functions in human cancer. However, the role of Prx I in hepatic tumorigenesis has not been characterized. Here we investigated the relevance and underlying mechanism of Prx I in hepatic tumorigenesis. Prx I increased in tumors of hepatocellular carcinoma (HCC) patients that aligned with overexpression of oncogenic H-ras. Prx I also increased in H-rasG12V transfected HCC cells and liver tumors of H-rasG12V transgenic (Tg) mice, indicating that Prx I may be involved in Ras-induced hepatic tumorigenesis. When Prx I was knocked down or deleted in HCC-H-rasG12V cells or H-rasG12V Tg mice, cell colony or tumor formation was significantly reduced that was associated with downregulation of pERK pathway as well as increased intracellular reactive oxygen species (ROS) induced DNA damage and cell death. Overexpressing Prx I markedly increased Ras downstream pERK/FoxM1/Nrf2 signaling pathway and inhibited oxidative damage in HCC cells and H-rasG12V Tg mice. In this study, we found Nrf2 was transcriptionally activated by FoxM1, and Prx I was activated by the H-rasG12V/pERK/FoxM1/Nrf2 pathway and suppressed ROS-induced hepatic cancer-cell death along with formation of a positive feedback loop with Ras/ERK/FoxM1/Nrf2 to promote hepatic tumorigenesis.