Miz1 Limits Tumor-promoting Function of Hepatocyte NF-κB independently of Its Transcriptional Activity in Chemical Hepatocarcinogenesis
Ontology highlight
ABSTRACT: NF-κB has a crucial tumor-suppression role in chemical hepatocarcinogenesis (HCC) by preventing hepatocyte apoptosis-induced compensatory proliferation. However, NF-κB is typically activated in chemical HCC animal models and in ~40% HCC patients, in which its role in tumor progression is largely not known. Here we report that transcription factor Miz1 limits tumor-promoting function of NF-κB independently of its transcriptional activity in chemical HCC. In a murine model, hepatocyte-specific deletion of Miz1 exacerbates HCC progression. Miz1 loss results in a unique sub-group of hepatocytes with upregulated NF-κB activity and pro-inflammatory cytokine production, skewing infiltrating macrophages toward M1-like pro-inflammatory phenotype. Mechanistically, Miz1 sequestrates and prevents IKK-phosphorylation of Metadherin (MTDH), thereby inhibiting NF-κB nuclear translocation and transcription activity. In HCC patient specimens, Miz1 expression is inversely correlated with phosphorylation of RelA and MTDH, and poor prognosis. Thus, Miz1 preventing hepatocytes from promoting infiltrating macrophage M1-like phenotype and inflammation in chemical HCC progression.
Project description:Previous studies have revealed that nuclear Miz1 is implicated in the regulation of several cancers mainly relying on its POZ domain. Current study, however, uncovers an unexpected function of cytoplasmic Miz1 in hepatocellular carcinoma (HCC). In vivo HCC models in Miz1 and Miz1(POZ) KO mice along with RNA-sequencing experiments show that hepatocyte specific ablation of Miz1 exacerbates TNF-α-induced NF-κB activation and promotes the progression of HCC independent of its transcriptional activity. Ubiquitination and proteosomal degradation of cytoplasmic Miz1 liberates its novel partner Metadherin (MTDH), and its site specific phosphorylation is critical to NF-κB activation. These findings reveal a brand new role of cytosolic Miz1 as a suppressor of HCC, and provide profound insights into liver cancer diagnosis and treatment.
Project description:Miz1 Limits Tumor-promoting Function of Hepatocyte NF-κB independently of Its Transcriptional Activity in Chemical Hepatocarcinogenesis
Project description:Nuclear factor κB (NF-κB) pathway plays an important role in hepatocellular carcinoma (HCC) progression. miR-194 was previously shown to reduce the induction of NF-κB activity upon addition of tumor necrosis factor α (TNFα). To clarify the molecular mechanism responsible for the effect of miR-194 on NF-κB pathway, mRNA microarray assays were performed to identify the genes that were suppressed by miR-194. HEK-293T cells transfected with miR-194 mimics were cultured for RNA extraction and hybridization on Affymetrix mRNA microarrays. These were compared against the control, which were HEK-293T cells transfected with negative control mimics.
Project description:Nuclear factor κB (NF-κB) pathway plays an important role in hepatocellular carcinoma (HCC) progression. miR-194 was previously shown to reduce the induction of NF-κB activity upon addition of tumor necrosis factor α (TNFα). To clarify the molecular mechanism responsible for the effect of miR-194 on NF-κB pathway, mRNA microarray assays were performed to identify the genes that were suppressed by miR-194.
Project description:Tumor microenvironment with distinctive cell types and a complex extracellular matrix has a tremendous effect on cancer progression. In the present study we investigated the effects of proinflammatory (M1) and immunosuppressive (M2) macrophages on melanoma cell hyaluronan (HA) metabolism and inflammatory response. M1 macrophages stimulated the formation of a thick pericellular HA matrix in melanoma cells, and the overall HA synthesis was increased due to upregulation of HA synthases (HAS) 1 and 2. HAS2 silencing reversed the effect of M1 CM (conditioned medium) on pericellular HA coat formation, similarly as the chemical inhibitors for TNFR (R-7050), IKK2 (IKK16) and MEK (U0126). RNA sequencing analysis indicated that several inflammation related genes (IL1, IL6, CXCL6) were highly upregulated in M1 CM treated melanoma cells. Gene set enrichment analysis identified that genes related to inflammatory response and TNFα signaling via NF-κB are enriched in M1 CM treated cells. Our results indicate that the activation of MEK and TNFR-NF-κB signaling leads to HAS2 upregulation, while MEK signaling pathway is not involved in cytokine upregulation. Furthermore, HAS2 silencing downmodulated the M1 CM-induced cytokine expression. Our results indicate that proinflammatory macrophages induce an inflammatory response in melanoma cells, where HAS2 upregulation associates with a protumor inflammatory gene signature.
Project description:Background:
HCC incidence is increasing worldwide due to the obesity epidemic, which drives metabolic dysfunction-associated steatohepatitis (MASH) that can lead to HCC. However, the molecular pathways driving MASH-HCC are poorly understood. We have previously reported that male mice with haploinsufficiency of hypoxia-associated factor, HAF (SART1+/-) spontaneously develop MASH-HCC. However, the cell type(s) responsible for HCC associated with HAF loss are unclear.
Results:
We generated SART1-floxed mice, which were crossed with mice expressing Cre-recombinase within hepatocytes (Alb-Cre; hepS-/-) or myeloid cells (LysM-Cre, macS-/-). HepS-/- mice (both male and female) developed HCC associated with profound inflammatory and lipid dysregulation suggesting that HAF protects against HCC primarily within hepatocytes. HAF-deficient hepatocytes showed decreased P-p65 and P-p50 and in many components of the NF-kB pathway, which was recapitulated using HAF siRNA in vitro. HAF depletion also triggered apoptosis, suggesting that HAF protects against HCC by suppressing hepatocyte apoptosis. We show that HAF regulates NF-kB activity by regulating transcription of TRADD and RIPK1. Mice fed a high-fat diet (HFD) showed marked suppression of HAF, P-p65 and TRADD within their livers after 26 weeks, but showed profound upregulation of these proteins after 40 weeks, implicating deregulation of the HAF-NF-kB axis in the progression to MASH. In humans, HAF was significantly decreased in livers with simple steatosis but significantly increased in HCC compared with normal liver.
Conclusions:
HAF is novel transcriptional regulator of the NF-kB pathway and is a key determinant of cell fate during progression to MASH and MASH-HCC.
Project description:Over activation of NF-κB has close relationship with hepatitis and hepatocellular carcinoma (HCC). In this study, by manipulating NF-κB activity with its recognized activator TNFα and using ChIP-seq and RNA-seq techniques, we identified 699 NF-κB direct target genes (DTGs) in a widely used HCC cell line, HepG2, including 399 activated and 300 repressed genes. In these NF-κB DTGs, 216 genes (126 activated and 90 repressed genes) are among the current HCC gene signature. Functional annotation revealed that NF-κB DTGs in HepG2 cell are mainly related with many typical NF-κB-related biological processes, such as immune system process, response to stress, response to stimulus, defense response and signaling pathways of NF-kappa B. Some NF-κB DTGs are also involved in Hepatitis C and B pathways. The NF-κB DTGs were further confirmed by detecting the NF-κB binding and expression of 14 genes with ChIP-PCR and RT-PCR.
Project description:Over activation of NF-κB has close relationship with hepatitis and hepatocellular carcinoma (HCC). In this study, by manipulating NF-κB activity with its recognized activator TNFα and using ChIP-seq and RNA-seq techniques, we identified 699 NF-κB direct target genes (DTGs) in a widely used HCC cell line, HepG2, including 399 activated and 300 repressed genes. In these NF-κB DTGs, 216 genes (126 activated and 90 repressed genes) are among the current HCC gene signature. Functional annotation revealed that NF-κB DTGs in HepG2 cell are mainly related with many typical NF-κB-related biological processes, such as immune system process, response to stress, response to stimulus, defense response and signaling pathways of NF-kappa B. Some NF-κB DTGs are also involved in Hepatitis C and B pathways. The NF-κB DTGs were further confirmed by detecting the NF-κB binding and expression of 14 genes with ChIP-PCR and RT-PCR.
Project description:The inflammatory tumor microenvironment (TME) is a key driver of tumor-promoting processes. Tumor-associated macrophages are one of the main immune cell types in the TME and their density increases during cancer progression. Here, we investigated the influence of pro-inflammatory (M1) and immunosuppressive (M2) macrophages on prostate cancer lineage plasticity. Our findings reveal that M1 macrophage secreted factors upregulate genes related to stemness while downregulating genes associated with androgen response in LNCaP prostate cancer cells. Cancer stem cell plasticity markers NANOG, KLF4, SOX2, OCT4 and CD44 were stimulated by the secreted factors from M1 macrophages. Moreover, AR and its target gene KLK3 were observed to be suppressed in LNCaP cells treated exposed to secreted factors from M1 macrophages. Inhibition of NF-κB signaling using the IKK16 inhibitor resulted in downregulation of NANOG, SOX2 and CD44. Our study highlights that the secreted factors from M1 macrophages drive prostate cancer cell plasticity by upregulating the expression of cancer stem cell plasticity markers through NF-κB signaling pathway.
Project description:Post-translational modification of NF-κB subunits provides a mechanism to differentially regulate their activity in response to the many stimuli that can induce this pathway. However, the physiological significance of these modifications is largely unknown and it remains unclear if these have a critical role in the normal and pathological functions of NF-κB in vivo. Among these, phosphorylation of the RelA(p65) Thr505 residue has been described as an important regulator of NF-κB activity in cell lines but its physiological significance was not known. Therefore, to learn more about the role of this pathway in vivo, we generated a knockin mouse with a RelA T505A mutation. Unlike RelA knockout mice, the RelA T505A mice develop normally but exhibit aberrant hepatocyte proliferation following liver partial hepatectomy or damage resulting from carbon tetrachloride treatment. Consistent with these effects, RelA T505A mice exhibit earlier onset of cancer in the N-nitrosodiethylamine (DEN) model of hepatocellular carcinoma. This data reveals a critical pathway controlling NF-κB function in the liver that acts to suppress tumour-promoting activities of RelA.