adrenomedullin and Carcinoma--Hepatocellular

The transcriptional profile of adrenomedullin (AM), a new metastasis-related factor involved in hepatocellular carcinoma (HCC), and its specific receptors (CLR, RAMP1, RAMP3) were evaluated in liver tissues of HCV-positive HCC subjects undergoing liver transplantation (LR) and in donors (LD). AM and its specific receptor expression were also assessed in extracellular vesicles (EVs) secreted by tumorigenic (HepG2) and non-tumorigenic (WRL68) cells by Real-Time PCR. AM expression resulted significantly elevated in LR concerning LD (p = 0.0038) and, for the first time, significantly higher levels in HCC patients as a function of clinical severity (MELD score), were observed. RAMP3 and CLR expression increased in LR as a function of clinical severity while RAMP1 decreased. Positive correlations were found among AM, its receptors, and apoptotic markers. No AM mRNA expression difference was observed between HepG2 and WRL68 EVs. RAMP1 and RAMP3 resulted lower in HepG2 concerning WRL68 while significantly higher levels were observed for CLR. While results at tissue level characterize AM as a regulator of carcinogenesis-tumor progression, those obtained in EVs do not indicate AM as a target candidate, neither as a pathological biomarker nor as a marker involved in cancer therapy.

Topics: Adrenomedullin; Calcitonin Receptor-Like Protein; Carcinogenesis; Carcinoma, Hepatocellular; Cell Line; Humans; Liver Neoplasms; Receptor Activity-Modifying Protein 2; Receptor Activity-Modifying Protein 3

Adrenomedullin (ADM) is an angiogenic peptide that has been shown to increase the risk of endometrial hyperplasia and to promote tumor cell survival following hypoxia. ADM may induce microvessel proliferation and partially decrease hypoxia in solid tumors, thus contributing to the proliferation of tumor cells, as well as tumor invasion and metastasis. However, the impact of hypoxia‑induced ADM expression on hepatocellular carcinoma (HCC) cells requires further elucidation. In the present study it was found that the levels of ADM mRNA in tumor tissue from patients with HCC were significantly increased compared with the mRNA levels in adjacent non‑tumorous liver tissue. Under hypoxic conditions, the mRNA and protein levels of ADM, as well as those of the cancer‑promoting genes vascular endothelial growth factor and hypoxia‑inducible factor 1α, were significantly elevated in a time‑dependent manner in three human HCC cell lines. In addition, knockdown of ADM expression using short hairpin RNA (shRNA) in SMMC‑7721 cells resulted in apoptosis that was not observed in untransfected cells. Furthermore, combined treatment with cisplatin and ADM‑shRNA significantly decreased tumor growth in vivo compared with treatment with cisplatin or ADM‑shRNA alone. These data demonstrate that ADM acts as a critical promoter of cell cycle progression in HCC and that the inhibition of ADM may be an effective interventional therapeutic strategy in HCC.

Topics: Adrenomedullin; Adult; Aged; Animals; Carcinoma, Hepatocellular; Cell Hypoxia; Cell Line, Tumor; Cell Proliferation; Cisplatin; Dose-Response Relationship, Drug; Female; Gene Expression Regulation, Neoplastic; Hep G2 Cells; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Liver Neoplasms; Male; Mice; Mice, Inbred BALB C; Middle Aged; Promoter Regions, Genetic; RNA Interference; RNA, Messenger; RNA, Small Interfering; Vascular Endothelial Growth Factor A

We studied the roles of JMJD1A and its target gene ADM in the growth of hepatocellular carcinomas (HCCs) and breast cancer cells under hypoxic conditions. Hypoxia stimulated HepG2 and Hep3B cell proliferation but had no effect on MDA-MB-231 cell proliferation. Interestingly, the JMJD1A and ADM expressions were enhanced by hypoxia only in HepG2 and Hep3B cells. Our ChIP results showed that hypoxia-induced HepG2 and Hep3B cell proliferation is mediated by JMJD1A upregulation and subsequent decrease in methylation in the ADM promoter region. Furthermore, JMJD1A gene silencing abrogated the hypoxia-induced ADM expression and inhibited HepG2 and Hep3B cell growth. These data suggest that JMJD1A might function as a proliferation regulator in some cancer cell types.

Topics: Adrenomedullin; Animals; Blotting, Western; Carcinoma, Hepatocellular; Cell Hypoxia; Cell Line, Tumor; Cell Proliferation; DNA Methylation; Female; Gene Expression Regulation, Neoplastic; Hep G2 Cells; Humans; Jumonji Domain-Containing Histone Demethylases; Liver Neoplasms; Mice; Mice, Inbred BALB C; Mice, Nude; Promoter Regions, Genetic; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Xenograft Model Antitumor Assays

Adrenomedullin is implicated in tumor progression and induced by hypoxia. We evaluated if adrenomedullin signaling is active in hepatocellular carcinoma (HCC), especially under hypoxic conditions, and to analyze its prognostic implication in HCC patients. HCC cells expressed adrenomedullin and its receptor, and hypoxia induced adrenomedullin expression. Adrenomedullin stimulated HCC cell growth via Akt activation, which was prevented by adrenomedullin peptide inhibitor. Clinico-pathological analysis revealed adrenomedullin extent was related to vascular invasion and N-cadherin intensity, which were reported to indicate a poor prognosis. In conclusion, adrenomedullin signaling is hypoxia-inducible and functionally active in HCCs, and its expression may be a prognostic factor.

Topics: Adrenomedullin; Adult; Base Sequence; Blotting, Western; Carcinoma, Hepatocellular; Cell Division; Cell Line; DNA Primers; Female; Humans; Hypoxia; Immunohistochemistry; Liver Neoplasms; Male; Middle Aged; Prognosis; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction

Acyl-CoA:cholesterol acyltransferase (ACAT) is an important enzyme in the pathways of cholesterol esterification. It has been shown that new ACAT inhibitor 1-(2,6-diisopropyl-phenyl)-3-[4-(4'-nitrophenylthio)phenyl] urea (VULM1457) significantly reduced atherogenic activity in animal experimental atherosclerosis. Proliferative hormone adrenomedullin (AM) has been shown to be released in response to hypoxia, however, its role in cellular protection has remained elusive. The effect of increased local production of AM in cells and resultant down-regulation of AM receptors has not been investigated yet. We hypothesized that increased expression of AM in hypoxic cells was the result of excessive AM production with resultant AM receptor down-regulation, surface-membrane protein degradation and that the new specific ACAT inhibitor would reduce AM induction in hypoxia and thus proliferation of cells. In order to investigate specific cellular AM signaling and protection induced by VULM1457, we characterized specific surface-membrane [125I]AM receptors expressed on cells, evaluated AM secretion (RIA assays), AM mRNA expression in cultured cells (RT-PCR analysis) and proliferation (incorporation of [3H]thymidine) in control, hypoxic and metabolically stressed human hepatoblastoma cell lines exposed to gradually increasing concentrations of VULM1457. The new ACAT inhibitor VULM1457 in concentration 0.03 and 0.1 micromol/l significantly down-regulated specific AM receptors on HepG2 cells, reduced AM secretion of HepG2 cells exposed to hypoxia. These results suggest that VULM1457, as new member of ACAT family of inhibitors could negatively regulate cell proliferation induced by AM, which may correlate with down-regulation of membrane-bound AM receptors on HepG2 cells, and moreover, with the induction and expression of AM in hypoxia.

Topics: Adrenomedullin; Carcinoma, Hepatocellular; Cell Hypoxia; Cell Line, Tumor; Clofibrate; Dose-Response Relationship, Drug; Down-Regulation; Humans; Peptides; Receptors, Adrenomedullin; Receptors, Peptide; Sterol O-Acyltransferase