The full scale of human miRNome in specific cell or tissue, especially in cancers, remains to be determined. An in-depth analysis of miRNomes in human normal liver, hepatitis liver, and ...hepatocellular carcinoma (HCC) was carried out in this study. We found nine miRNAs accounted for ∼88.2% of the miRNome in human liver. The third most highly expressed miR-199a/b-3p is consistently decreased in HCC, and its decrement significantly correlates with poor survival of HCC patients. Moreover, miR-199a/b-3p can target tumor-promoting PAK4 to suppress HCC growth through inhibiting PAK4/Raf/MEK/ERK pathway both in vitro and in vivo. Our study provides miRNomes of human liver and HCC and contributes to better understanding of the important deregulated miRNAs in HCC and liver diseases.
► Identification of miRNomes in human normal liver, hepatitis liver and HCC ► miR-199a/b-3p is the most consistently decreased miRNA in HCC ► Low miR-199-3p expression correlates with poor survival of HCC patients ► miR-199-3p inhibits PAK4/Raf/MEK/ERK prosurvival pathway in HCC
The ankyrin‐repeat–containing, SH3‐domain–containing, and proline‐rich‐region–containing protein (ASPP) family of proteins regulates apoptosis through interaction with p53 and its family members. ...This study evaluated the epigenetic regulation of ASPP1 and ASPP2 in hepatitis B virus (HBV)‐positive hepatocellular carcinoma (HCC) and explores the effects of down‐regulation of ASPP1 and ASPP2 on the development of HCC. HCC cell lines and tissues from HCC patients were used to examine the expression and methylation of ASPP1 and ASPP2. The expression of ASPP1 and ASPP2 was diminished in HCC cells by epigenetic silence owing to hypermethylation of ASPP1 and ASPP2 promoters. Analyses of 51 paired HCC and surrounding nontumor tissues revealed that methylation of ASPP1 and ASPP2 was associated with the decreased expression of ASPP1 and ASPP2 in tumor tissues and the early development of HCC. Moreover, ASPP2 became methylated upon HBV x protein (HBx) expression. The suppressive effects on tumor growth by ASPP1 and ASPP2 were examined with RNA interference‐mediated gene silence. Down‐regulation of ASPP1 and ASPP2 promoted the growth of HCC cells in soft agar and in nude mice and decreased the sensitivity of HCC cells to apoptotic stimuli. Conclusion: ASPP1 and ASPP2 genes are frequently down‐regulated by DNA methylation in HBV‐positive HCC, which may play important roles in the development of HCC. These findings provide new insight into the molecular mechanisms leading to hepatocarcinogenesis and may have potent therapeutic applications. (HEPATOLOGY 2010;51:142–153.)
Purpose: To investigate Tip30 promoter methylation status in human hepatocellular carcinoma (HCC) and the correlation with clinicopathologic features and
prognosis.
Experimental Design: The ...methylation status of CpG islands in Tip30 promoter was examined in 15 HCC cell lines as well as 59 paired HCC and adjacent nontumor tissues. The associations between
Tip30 methylation status and the survival of patients were analyzed.
Results: Tip30 promoter was hypermethylated in 6 of 10 HCC cell lines with reduced Tip30 mRNA. DNA methyltransferase inhibitor, 5-aza-2′-deoxycytidine, greatly enhanced TIP30 expression and sensitized HCC cells
to cytotoxic drug-induced cell death. The promoter region of Tip30 was identified and the main promoter activity was located in the -135 to -45 region sited within a CpG island. The minimal
promoter element contained four Sp1 binding sites, which were hypermethylated in HCC cell-derived promoters. Moreover, analyses
of Tip30 promoter methylation status in 59 paired HCC tissues showed that 47% of the cases were hypermethylated. Recurrence rate (95%
versus 67%; P = 0.011) and mortality (82% versus 53%; P = 0.033) were significantly higher in patients with methylated Tip30 . Disease-free survival was significantly higher in patients with unmethylated Tip30 (33.3% versus 4.5%; P = 0.036).
Conclusions: Our results show that epigenetic silencing of Tip30 gene expression by CpG island DNA hypermethylation is associated with poor prognosis in patients with HCC.
It has been previously demonstrated that the 30‐kDa Tat‐interacting protein (TIP30) plays an important role in the suppression of hepatocarcinogenesis by acting as a tumor suppressor. Here we report ...that TIP30 suppresses metastasis of hepatocellular carcinoma (HCC) through inhibiting the transcription of osteopontin (OPN), a key molecule in the development of tumor metastasis. The expression of TIP30 messenger RNA was reverse to that of OPN messenger RNA in HCC cell lines. Ectopic expression of TIP30 greatly suppressed OPN expression, inhibited invasion of HCC cells through extracellular matrix (ECM) and adhesion with fibronectin in vitro, whereas down‐regulation of TIP30 by RNA‐mediated interference enhanced OPN expression and promoted metastatic abilities of HCC cells in vitro. Moreover, overexpression of TIP30 significantly inhibited the growth and lung metastases of HCC cells in nude mice. In contrast, down‐regulation of TIP30 greatly promoted tumor cell growth and metastases in vivo. TIP30 repressed OPN transcription through interaction with Ets‐1 and suppressed the transcriptional activity of Ets‐1 and synergistic actions of Ets‐1 and alkaline phosphatase‐1. Thus, TIP30 may act as an Ets‐1 modulator and inhibit tumor metastasis through abrogating Ets‐1–dependent transcription. Moreover, expression of TIP30 was inversely associated with OPN expression in HCC tissue samples as detected by immunohistochemistry assay. Conclusion: Our results reveal a novel pathway by which OPN and possibly other Ets‐1 target genes involved in tumor metastasis are regulated by TIP30 and elucidate a mechanism for metastasis promoted by TIP30 deficiency. (HEPATOLOGY 2008.)
In hepatocellular carcinoma (HCC), biomarkers for prediction of prognosis and response to immunotherapy such as interferon-α (IFN-α) would be very useful in the clinic. We found that expression of ...retinoic acid-inducible gene-I (RIG-I), an IFN-stimulated gene, was significantly downregulated in human HCC tissues. Patients with low RIG-I expression had shorter survival and poorer response to IFN-α therapy, suggesting that RIG-I is a useful prognosis and IFN-α response predictor for HCC patients. Mechanistically, RIG-I enhances IFN-α response by amplifying IFN-α effector signaling via strengthening STAT1 activation. Furthermore, we found that RIG-I deficiency promotes HCC carcinogenesis and that hepatic RIG-I expression is lower in men than in women. RIG-I may therefore be a tumor suppressor in HCC and contribute to HCC gender disparity.
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•RIG-I is the most significantly downregulated IFN-stimulated gene in HCC•Patients with low RIG-I have shorter survival and poorer response to IFN-α therapy•RIG-I amplifies IFN-JAK-STAT effector signaling by enhancing STAT1 activation•Lower hepatic RIG-I expression in men may contribute to HCC gender disparity
Epithelial to mesenchymal transition (EMT), and the reverse mesenchymal to epithelial transition (MET), are known examples of epithelial plasticity that are important in kidney development and cancer ...metastasis. Here we identify ASPP2, a haploinsufficient tumour suppressor, p53 activator and PAR3 binding partner, as a molecular switch of MET and EMT. ASPP2 contributes to MET in mouse kidney in vivo. Mechanistically, ASPP2 induces MET through its PAR3-binding amino-terminus, independently of p53 binding. ASPP2 prevents β-catenin from transactivating ZEB1, directly by forming an ASPP2-β-catenin-E-cadherin ternary complex and indirectly by inhibiting β-catenin's N-terminal phosphorylation to stabilize the β-catenin-E-cadherin complex. ASPP2 limits the pro-invasive property of oncogenic RAS and inhibits tumour metastasis in vivo. Reduced ASPP2 expression results in EMT, and is associated with poor survival in hepatocellular carcinoma and breast cancer patients. Hence, ASPP2 is a key regulator of epithelial plasticity that connects cell polarity to the suppression of WNT signalling, EMT and tumour metastasis.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
R3; Direct intratumoral introduction of therapeutic or regulatory genes is a developing technology with potential application for cancer gene therapy. Macrophage inflammatory protein-1 beta (MIP-1β) ...is a chemokine which can chemoattract immune cells such as T cells. In the present study, murine colorectal adenocarcinoma CT26 cells were transfected with a recombinant adenovirus (AdhMIP-1β) carrying the human MIP-1β gene. 24 h post-transfection, hMIP-1β levels reached approximately 980 pg/ml in supernatants of 106 hMIP-1β-transfected CT26 cells. Moreover, the supernatants exhibited chemotactic activity for CD8+ T cells, CD4+ T cells, NK cells and immature DCs. Intratumoral injection of AdhMIP-1β significantly inhibited tumor growth and prolonged the survival time of tumor-bearing mice. Intratumoral hMIP-1β gene transfer also induced powerful tumor- specific CTL responses in vivo. The therapeutic effects of hMIP-1β gene therapy were greatly reduced following in vivo depletion of both CD4+ and CD8+T cells, but were unaffected by depletion of single T cell subsets. Immune cell depletion experiments also revealed that NK cells played an important role in hMIP-1β-induced antitumor responses. These results suggest that intratumoral expression of hMIP-1β has the potential effect to induce host antitumor immunity and may prove to be a useful form of cancer gene therapy.
Background & Aims iASPP is an inhibitory member of the ankyrin-repeat-, SH3-domain- and proline-rich-region-containing protein (ASPP) family; iASPP expression is up-regulated in different human tumor ...types. We explored the molecular mechanism increased expression of iASPP and its role in hepatocellular carcinoma (HCC). Methods iASPP expression levels in human liver samples and cell lines were determined by polymerase chain reaction, immunoblot, and immunohistochemical analyses. Luciferase reporter, chromatin immunoprecipitation, and electrophoretic mobility shift assays were used to measure transcriptional activation by nuclear factor-κB (NF-κB). Effects on tumor growth were characterized with MTS, soft agar colony formation, and flow cytometry analyses. Tumorigenicity of cells was studied in nude mice. Results Compared with normal liver cells or tissues, iASPP was expressed at significantly higher levels in HCC cell lines (9/14) and liver samples from patients with HCC, cirrhosis, or hepatitis B virus infection. Increased expression of iASPP was significantly associated with time to recurrence and survival time of patients with HCC. NF-κB activation increased the expression of iASPP through p65/p50 binding to a putative NF-κB–binding site in the iASPP promoter; hepatitis B virus X gene product might up-regulate expression of iASPP. Transgenic expression of iASPP promoted tumor cell proliferation and resistance to chemotherapeutic drugs in vitro and in vivo. Conclusions iASPP is up-regulated in HCC; it is a direct transcription target of NF-κB. Increased iASPP expression contributes to tumor progression by proliferative and antiapoptotic effects. iASPP might be developed as an HCC therapeutic target or to sensitize cancer cells to chemotherapeutic drugs; it might also be used as a prognostic factor.
Rice blast disease caused by
Magnaporthe oryzae
is an important limiting factor to rice production in the world. Introgression of blast resistance genes into improved germplasm by marker-assisted ...selection has been considered as an effective and environmentally beneficial means to control this disease.
Pike
, a broad-spectrum blast resistance gene, was cloned by map-based strategy recently in our laboratory. Two adjacent CC-NBS-LRR genes (designated as
Pike
-
1
and
Pike
-
2
) were required for
Pike
-mediated resistance. In the current study, sequence alignment of the SNP G1328C and the SNP-surrounding region let us find that the
Pik
DNA variants of the studied rice lines appear to be divided into G-, C-, T- and G’-types. Based on the four genotypes, a
Pike
-specific marker system consisting of three PCR-based markers CP-G1328C, CP-G1328T and CP-G1328G’ was developed and used to effectively differentiate G-type allele from each of the others. Using this marker system, we investigated distribution of the
Pik
DNA variants in a set of 326 rice varieties or breeding lines and found that there were 2, 130, 135 and 59 rice lines identified to carry G-, C-, T- and G’-type alleles, respectively. In addition, with sequence data of the SNP G1328C-containing genomic region derived from 56 rice lines, we constructed a phylogenetic tree with three major clades which just corresponded to the types of the
Pik
DNA variants described above.
Epithelial to mesenchymal transition (EMT), and the reverse mesenchymal to epithelial transition (MET), are known examples of epithelial plasticity that are important in kidney development and cancer ...metastasis. Here we identify ASPP2, a haploinsufficient tumour suppressor, p53 activator and PAR3 binding partner, as a molecular switch of MET and EMT. ASPP2 contributes to MET in mouse kidney in vivo. Mechanistically, ASPP2 induces MET through its PAR3-binding amino-terminus, independently of p53 binding. ASPP2 prevents beta-catenin from transactivating ZEB1, directly by forming an ASPP2-beta-catenin-E-cadherin ternary complex and indirectly by inhibiting beta-catenin's N-terminal phosphorylation to stabilize the beta-catenin-E-cadherin complex. ASPP2 limits the pro-invasive property of oncogenic RAS and inhibits tumour metastasis in vivo. Reduced ASPP2 expression results in EMT, and is associated with poor survival in hepatocellular carcinoma and breast cancer patients. Hence, ASPP2 is a key regulator of epithelial plasticity that connects cell polarity to the suppression of WNT signalling, EMT and tumour metastasis.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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