Many protein-coding oncofetal genes are highly expressed in murine and human fetal liver and silenced in adult liver. The protein products of these hepatic oncofetal genes have been used as clinical markers for the recurrence of hepatocellular carcinoma (HCC) and as therapeutic targets for HCC. Herein we examined the expression profiles of long noncoding RNAs (lncRNAs) found in fetal and adult liver in mice. Many fetal hepatic lncRNAs were identified; one of these, lncRNA-mPvt1, is an oncofetal RNA that was found to promote cell proliferation, cell cycling, and the expression of stem cell-like properties of murine cells. Interestingly, we found that human lncRNA-hPVT1 was up-regulated in HCC tissues and that patients with higher lncRNA-hPVT1 expression had a poor clinical prognosis. The protumorigenic effects of lncRNA-hPVT1 on cell proliferation, cell cycling, and stem cell-like properties of HCC cells were confirmed both in vitro and in vivo by gain-of-function and loss-of-function experiments. Moreover, mRNA expression profile data showed that lncRNA-hPVT1 up-regulated a series of cell cycle genes in SMMC-7721 cells. By RNA pulldown and mass spectrum experiments, we identified NOP2 as an RNA-binding protein that binds to lncRNA-hPVT1. We confirmed that lncRNA-hPVT1 up-regulated NOP2 by enhancing the stability of NOP2 proteins and that lncRNA-hPVT1 function depends on the presence of NOP2. Conclusion: Our study demonstrates that the expression of many lncRNAs is up-regulated in early liver development and that the fetal liver can be used to search for new diagnostic markers for HCC. LncRNA-hPVT1 promotes cell proliferation, cell cycling, and the acquisition of stem cell-like properties in HCC cells by stabilizing NOP2 protein. Regulation of the lncRNA-hPVT1/NOP2 pathway may have beneficial effects on the treatment of HCC. (Hepatology 2014;60:1278–1290)
Hepatocytes are the primary functional cells of the liver, performing its metabolic, detoxification, and endocrine functions. Functional hepatocytes are extremely valuable in drug discovery and evaluation, as well as in cell therapy for liver diseases. However, it has been a long-standing challenge to maintain the functions of hepatocytes in vitro. Even freshly isolated hepatocytes lose essential functions after short-term culture for reasons that are still not well understood. In the present study, we find that mechanical tension-induced yes-associated protein activation triggers hepatocyte dedifferentiation. Alleviation of mechanical tension by confining cell spreading is sufficient to inhibit hepatocyte dedifferentiation. Based on this finding, we identify a small molecular cocktail through reiterative chemical screening that can maintain hepatocyte functions over the long term and in vivo repopulation capacity by targeting actin polymerization and actomyosin contraction. Our work reveals the mechanisms underlying hepatocyte dedifferentiation and establishes feasible approaches to maintain hepatocyte functions.
20 October 2014 in Proceedings of the National Academy of Sciences
Significance: With a combination of HPLC and carbon fiber electrodes, we demonstrate that grafted neural stem cells directly release dopamine in the damaged striatum in vivo and partially rescue a Parkinson’s disease (PD) model. (i) Primitive neural stem cell–dopamine-like neuron (pNSC–DAn) retained tyrosine hydroxylase expression and reduced the PD-like asymmetric rotation; (ii) depolarization-evoked dopamine release and reuptake were significantly rescued in striatum in vitro (brain slices) and in vivo, as determined jointly by microdialysis-based HPLC and electrochemical micro-carbon fiber electrodes; and (iii) the rescued dopamine was released directly from the grafted pNSC–DAn (not from the injured original cells). Thus, pNSC–DAn grafts release and reuptake dopamine in the striatum in vivo and alleviate PD symptoms in rats, providing proof-of-concept for human clinical translation.
Interleukin-13 (IL-13), a Th2 cytokine, plays an important role in fibrosis, inflammation, tissue hyperresponsiveness and tumor development. Although studies have demonstrated that IL-13 exerts its roles through signal transducer and activator of transcription 6 (STAT6) signaling pathway, recent studies have revealed that I kappa B kinase (IKK)/nuclear factor kappa B (NFκB) pathway may also be involved in. The aim of this study was to investigate whether IL-13 delivers signals to IKKβ/NFκBp65 and whether autophagy genes are IL-13-induced the activation of NFκBp65 transcriptional targets in fibroblasts of breast tumor stroma. We examined the phosphorylation of IKKβ, the activation of NFκBp65 and NFκBp65-targeted autophagy genes in fibroblasts co-cultured with breast cancer cells under the condition of IL-13 stimulation. Results of this study showed that IL-13 induced IKKβ phosphorylation in the fibroblast line ESF co-cultured with breast cancer cell line BT474, and subsequently NFκBp65 was activated and aimed at beclin 1 and microtubule-associated protein 1 light chain 3 B (MAP1LC3B or LC3B) in these ESF cells. BMS345541, an inhibitor of IKK/NFκB pathway, significantly inhibited the IL-13-induced the activation of NFκB and also inhibited NFκB-targeted beclin 1 and LC3B expression. Our results suggest that IL-13 regulates beclin 1 and LC3B expression through IKKβ/NFκBp65 in fibroblasts co-cultured with breast cancer cells, and IL-13 plays role in activating IKKβ/NFκBp65.
1 March 2021 in Pesticide Biochemistry and Physiology