Project description:mTORC1-driven noninflammatory HCC and provide insight into further development of a protective strategy against noninflammatory HCC. Background & Aims: Mammalian target of rapamycin complex 1 (mTORC1) is frequently hyperactivated in hepatocellular carcinoma (HCC). Cases of HCC without inflammation and cirrhosis are not rarely seen in clinics. However, the molecular basis of noninflammatory HCC remains unclear. Methods: Spontaneous noninflammatory HCC in mice was triggered by constitutive elevation of mTORC1 by liver-specific Tsc1 knockout (LTsc1KO). A multi-omics approach was utilized on tumor tissues to better understand the molecular basis for the development of HCC in the LTsc1KO model. Results: We showed that LTsc1KO in mice triggered spontaneous noninflammatory HCC, with molecular characteristics similar to those of diethylnitrosamine-mediated noncirrhotic HCC. Mitochondrial and autophagy defects, as well as hepatic metabolic disorder were manifested in HCC development by LTsc1KO. mTORC1 activation on its own regulated an oncogenic network (DNA-damage-inducible transcript 4, nuclear protein 1 and fibroblast growth factor 21), and mTORC1–signal transducer and activator of transcription pathway crosstalk that altered specific metabolic pathways contributed to the development of noninflammatory HCC. Conclusion: Our findings reveal the mechanisms of mTORC1-driven noninflammatory HCC and provide insight into further development of a protective strategy against noninflammatory HCC.
Project description:Background and aimsMammalian target of rapamycin complex 1 (mTORC1) is frequently hyperactivated in hepatocellular carcinoma (HCC). Cases of HCC without inflammation and cirrhosis are not rarely seen in clinics. However, the molecular basis of non-inflammatory HCC remains unclear.MethodsSpontaneous non-inflammatory HCC in mice was triggered by constitutive elevation of mTORC1 by liver-specific TSC1 knockout (LTsc1KO). A multi-omics approach was utilized on tumor tissues to better understand the molecular basis for the development of HCC in the LTsc1KO model.ResultsWe showed that LTsc1KO in mice triggered spontaneous non-inflammatory HCC, with molecular characteristics similar to those of diethylnitrosamine-mediated non-cirrhotic HCC. Mitochondrial and autophagy defects, as well as hepatic metabolic disorder were manifested in HCC development by LTsc1KO. mTORC1 activation on its own regulated an oncogenic network (DNA-damage-inducible transcript 4, nuclear protein 1, and fibroblast growth factor 21), and mTORC1-signal transducer and activator of transcription pathway crosstalk that altered specific metabolic pathways contributed to the development of non-inflammatory HCC.ConclusionOur findings reveal the mechanisms of mTORC1-driven non-inflammatory HCC and provide insight into further development of a protective strategy against non-inflammatory HCC.
Project description:Gp130 receptor engagement on neoplastic cells provides a link by which an inflammatory microenvironment facilitates tumour promotion. Although hyperactivation of the gp130-dependent Stat3 signalling node is commonly observed in solid tumours, Stat3 remains a challenging therapeutic target. To mimic excessive Stat3 signalling, we molecularly validate the gp130FF mouse as a preclinical model for inflammation-associated intestinal-type gastric cancer (IGC), with aberrant mammalian target of rapamycin (mTOR) pathway activity as shared feature. Accordingly, administration of the mTorc1 inhibitor RAD001 reversibly reduced IGC burden in gp130FF mice and suppressed colitis-associated cancer in wild-type mice. Since the therapeutic effect of RAD001 occurs independently of Stat3 hyperactivation, which is also dispensable for gp130-dependent engagement of the PI3K/Akt/mTorc1 pathway, we conclude that mTorc1 signalling limits tumour promoting Stat3 activity The mouse whole-genome gene expression profiling was performed on Illumina's MouseWG-6 v2.0 Expression BeadChips for 24 mice, with 8 mice in each group (gp130WT antral tissue, gp130FF unaffected antral tissue and gp130FF tumour tissue).
Project description:Gp130 receptor engagement on neoplastic cells provides a link by which an inflammatory microenvironment facilitates tumour promotion. Although hyperactivation of the gp130-dependent Stat3 signalling node is commonly observed in solid tumours, Stat3 remains a challenging therapeutic target. To mimic excessive Stat3 signalling, we molecularly validate the gp130FF mouse as a preclinical model for inflammation-associated intestinal-type gastric cancer (IGC), with aberrant mammalian target of rapamycin (mTOR) pathway activity as shared feature. Accordingly, administration of the mTorc1 inhibitor RAD001 reversibly reduced IGC burden in gp130FF mice and suppressed colitis-associated cancer in wild-type mice. Since the therapeutic effect of RAD001 occurs independently of Stat3 hyperactivation, which is also dispensable for gp130-dependent engagement of the PI3K/Akt/mTorc1 pathway, we conclude that mTorc1 signalling limits tumour promoting Stat3 activity
Project description:Lung cancer is the second leading cause of cancer death worldwide and is strongly associated with cisplatin resistance. The transcription factor STAT3 is constitutively activated in cancer cells and coordinates critical cellular processes as survival, self-renewal, and inflammation. In several types of cancer, STAT3 controls the development, immunogenicity, and malignant behavior of tumor cells while dictates the responsiveness to radio- and chemotherapy. It is known that STAT3 phosphorylation on Ser727 by mTOR is necessary for its maximal activation, but the crosstalk between STAT3 and mTOR signaling in cisplatin resistance remains elusive. In this study, using a proteomic label-based approach, we reveal important targets and signaling pathways increased and decreased in cisplatin-resistant A549 lung adenocarcinoma cells.
Project description:Interleukin-27 (IL27) is a type-I-cytokine of the IL6/IL12 family predominantly secreted by activated macrophages and dendritic cells. Best understood are the effects of IL27 on immune cells where it has been described to have pro- or anti-inflammatory properties, either promoting TH1 responses or suppressing TH1 and TH2 responses. The action on other cell types is less well studied. In the liver, IL27 expression was observed to be upregulated in patients with hepatitis B, and sera of hepatocellular carcinoma (HCC) patients contain significantly elevated levels of IL27 compared to healthy controls or patients with hepatitis and/or liver cirrhosis. We previously reported interferon-gamma-like antiviral activity of IL27 in hepatic cells. Here we further studied the effects of IL27 on HCC cells in comparison to other cytokines. We were especially interested in the relevance of the IL27-induced STAT3 activation. Thus we compared its response with those induced by IFNg (STAT1-dominated response) or IL6-type cytokines (IL6, Hyper-IL6 or OSM) (STAT3-dominated response). We find that in hepatocytes, IL27 induces an IFNg-like, STAT1-dependent transcriptional response, but we do not find an effective STAT3-dependent response. The availability of STAT1 seems critical in the shaping of the IL27 response, as the siRNA knock-down of STAT1 revealed its ability to induce the acute-phase protein gamma-fibrinogen, a typical IL6 family characteristic. Moreover, we describe a crosstalk between the signaling of IL6-type cytokines and IL27: responses to the gp130-engaging cytokine IL27 (but not those to IFNs) can be inhibited by IL6-type cytokine pre-stimulation, likely by a SOCS3-mediated mechanism. This experiment represents microarray analysis of three hepatocellular carcinoma cell lines treated with IL-27, IFNg, hyper-IL6 or OSM in combination with shRNA knockdown of STAT3.
Project description:The liver plays a protective role in myocardial infarction (MI). However, very little is known about the mechanisms. Here, we identify mineralocorticoid receptor (MR) as a pivotal nexus that conveys communications between the liver and the heart during MI. On one hand, hepatocyte MR deficiency and MR antagonist spironolactone both improve cardiac repair after MI through regulation on hepatic fibroblast growth factor 21 (FGF21), illustrating an MR/FGF21 axis that underlies the liver-to-heart protection against MI. On the other hand, an upstreaming acute interleukin-6 (IL6) / signal transducer and activator of transcription 3 (STAT3) pathway transmits the heart-to-liver signal to suppress MR expression after MI. Hepatocyte IL6 receptor (IL6R) deficiency and STAT3 deficiency both aggravate cardiac injury through their regulation on the MR/FGF21 axis. Therefore, we have unveiled an IL6/STAT3/MR/FGF21 signaling axis that mediates heart-liver crosstalk during MI. Targeting the signaling axis and the crosstalk may provide novel strategies to treat MI and heart failure.
Project description:We identified a novel mechanism by which IL-6/STAT3 signaling up-regulates CD133 expression and promotes HCC progression. STAT3 activation upregulates the expression of CD133 during liver carcinogenesis. Targeting STAT3-mediated CD133 overexpression may represent a promising therapeutic strategy for HCC patients via eradicating the liver tumor microenviornment. To develop novel cancer therapeutic strategies by identification of signaling pathways or biomarkers and understanding their functions on cancer stem cell biology, we determined CD133 expression and STAT3 activation with tumor microenvironment in HCC patient tissues. The relation of STAT3 activation and CD133 expression was investigated by luciferase assay, shRNA knock-down, and chromatin immunoprecipitation assay in HCC cells, and in vivo xenograft model.
Project description:We identified a novel mechanism by which IL-6/STAT3 signaling up-regulates CD133 expression and promotes HCC progression. STAT3 activation upregulates the expression of CD133 during liver carcinogenesis. Targeting STAT3-mediated CD133 overexpression may represent a promising therapeutic strategy for HCC patients via eradicating the liver tumor microenviornment.
Project description:The RNA biding protein, LARP1, has been proposed to function downstream of mTORC1 to positively regulate the translation of 5M-bM-^@M-^YTOP mRNAs such as ribosome protein (RP) mRNAs. However, its regulatory roles in mTORC1-mediated translation remain unclear. PAR-CLIP of LARP1 revealed its direct and dynamic interactions with RP mRNAs through pyrimidine-enriched sequences in the 5M-bM-^@M-^YUTR of RP mRNAs when mTOR activity is inhibited. Importantly, this LARP1 is a direct substrate of mTORC1 and S6K1/Akt, and phosphorylated LARP1 scaffolds mTORC1 on translation-competent mRNAs to facilitate 4EBP1 and S6K1 phosphorylation. Ablation of LARP1 causes multiple defects in the processes of translation including abnormal eIF4G1 interaction with RP mRNAs and inefficient RP mRNA elongation thereby reducing ribosome biogenesis and cell proliferation. These observations illustrate that LARP1 functions both an effector and a regulator for local mTORC1 activity, and acts as a molecular switch for ribosome biogenesis by sensing growth factor/nutrient signaling. LARP1-bound RNA regions were sequenced from HEK293T cells under growing or mTOR-inactive conditions. In parallel, mRNA abundance was quantified, in biological duplicate, from HEK293T cells under the same conditions.