[show abstract][hide abstract] ABSTRACT: The mammalian homolog of yeast Sir2 protein is the sirtuin family of histone deacetylases (HDACs), a NAD+-dependent protein deacetylase in humans. Accumulating evidence suggests that sirtuin 2 (SIRT2) co-localizes with the microtubule network and deacetylates α-tubulin, and is involved in various cellular processes including calorie restriction-dependent life span extension, mitotic cell cycle regulation, cellular apoptosis, DNA damage repair, and genomic silencing. However, the underlying mechanisms of action remains poorly understood, especially in hepatocarcinogenesis. Hence in this study, to determine the association between the aberrant expression of SIRT2 and liver cancer development and progression, SIRT2 expression was investigated in ten selected hepatocellular carcinoma (HCC) tissues and matched normal liver tissues, using RT-PCR and Western blot analysis. Next, SIRT2 was disrupted by siRNA-mediated protein knockdown method to investigate the biological role of SIRT2 in hepatocarcinogenesis in Hep3B cells. As a result, we identified that SIRT2 expression was significantly up-regulated in HCC tissues compared to corresponding normal liver tissues. In addition, suppression of SIRT2 caused regression of tumor cell growth and proliferation. We also found that SIRT2 could interact with α-tubulin and regulates the acetylation status of α-tubulin in Hep3B cells. In conclusion, we suggest that SIRT2 is aberrantly regulated in HCCs which may contribute to the mitogenic potential of tumor cells during the development and progression of HCC, and could be a novel molecular target for therapeutic intervention in liver cancer.
Molecular and Cellular Toxicology 08/2013; 7(4). · 0.72 Impact Factor
[show abstract][hide abstract] ABSTRACT: Aberrant regulation of histone deacetylase 2 (HDAC2) plays a pivotal role in the development of hepatocellular carcinoma (HCC), but, the underlying mechanism leading to HDAC2 overexpression is not well understood. We performed microRNA (miRNA) profiling analysis in a subset of HCCs, and identified four down-regulated miRNAs that may target HDAC2 in HCC. Ectopic expression of miRNA mimics evidenced that miR-145 suppresses HDAC2 expression in HCC cells. This treatment repressed cancer cell growth and recapitulated HDAC2 knockdown effects on HCC cells. In conclusion, we suggest that loss or suppression of miR-145 may cause aberrant overexpression of HDAC2 and promote HCC tumorigenesis.
[show abstract][hide abstract] ABSTRACT: Aberrant regulation of histone deacetylase 2 (HDAC2) was reported for gastric cancers. However, responsive cancer genes in disease onset and progression are less understood. HDAC2 expression was studied by qRT-PCR and western blotting. The functional consequences of HDAC2 knockdown on cell cycle regulation, programmed cell death and gene target identification was investigated by flow cytometry, western blotting, electron microscopy, anchorage-independent colony formation and cell migration assay and by whole-genome microarray. Therapeutic efficacy of HDAC2 knockdown was determined in nude mice with small hairpin expressing human gastric cancer cells. Epigenetic regulation of p16INK4a was studied by methylation-specific PCR and chromatin-IP to evidence HDAC2 or acetylated-histone-H4 binding at gene specific promoter sequences. HDAC2 gene and protein expression was significantly up-regulated in different histopathological grades of human gastric cancers and cancer cell lines. HDAC2 inactivation significantly reduced cell motility, cell invasion, clonal expansion and tumor growth. HDAC2 knockdown induced G1/S cell cycle arrest and restored activity of p16INK4a and the pro-apoptotic factors. This treatment caused PARP cleavage and hypophosphorylation of the Rb-protein, repressed cyclinD1, CDK4 and Bcl-2 expression and induced autophagic phenotype, i.e. LC3B-II conversion. Some gastric tumors and cancer cells displayed p16INK4a promoter hypermethylation but treatment with 5-aza-deoxycitidine restored activity. With others the methylation status was unchanged. Here, chromatin-IP evidenced HDAC2 binding. Nonetheless, expression of p16INK4a was restored by HDAC2 knockdown with notable histone-4-acetylation, as determined by chromatin-IP. Thus, p16INK4a is regulated by HDAC2. HDAC2 is a bona fide target for novel molecular therapies in gastric cancers.
Molecular Cancer Research 11/2012; · 4.35 Impact Factor
[show abstract][hide abstract] ABSTRACT: Persistent organic pollutants (POPs) are degradation-resistant anthropogenic chemicals that accumulate in the food chain and in adipose tissue, and are among the most hazardous compounds ever synthesized. However, their toxic mechanisms are still undefined. To investigate whether characteristic molecular signatures can discriminate individual POP and provide prediction markers for the early detection of POPs exposure in an animal model, we performed transcriptomic analysis of rat liver tissues after exposure to POPs. The six different POPs (toxaphene, hexachlorobenzene, chlordane, mirex, dieldrin, and heptachlor) were administered to 11-week-old male Sprague-Dawley rats, and after 48 h of exposure, RNAs were extracted from liver tissues and subjected to rat whole genome expression microarrays. Early during exposure, conventional toxicological analysis including changes in the body and organ weight, histopathological examination, and blood biochemical analysis did not reflect any toxicant stresses. However, unsupervised gene expression analysis of rat liver tissues revealed in a characteristic molecular signature for each toxicant, and supervised analysis identified 2,708 outlier genes that discerned the POPs exposure group from the vehicle-treated control. Combination analysis of two different multi-classifications suggested 384 genes as early detection markers for predicting each POP exposure with 100% accuracy. The data from large-scale gene expression analysis of a different POP exposure in rat model suggest that characteristic expression profiles exist in liver hepatic cells and multi-classification of POP-specific molecular signatures can discriminate each toxicant at an early exposure time. The use of these molecular markers may be more widely implemented in combination with more traditional techniques for assessment and prediction of toxicity exposure to POPs from an environmental aspect.
[show abstract][hide abstract] ABSTRACT: Predictions of toxicity are central for the assessment of chemical toxicity, and the effects of environmental toxic compounds are still a major issue for predicting potential human health risks. Among the various environmental toxicants, polycyclic aromatic hydrocarbons (PAHs) are an important class of environmental pollutant, and many PAHs are known or suspected carcinogens. In the present study, to investigate whether characteristic expression profiles of PAHs exist in rat liver and whether a characteristic molecular signature can discriminate and predict among different PAHs at an early exposure time, we analyzed the genome-wide expression profiles of rat livers exposed to PAHs (benzo[a]anthracene, benzo[a]pyrene, phenanthrene and naphthalene). At early time-point PAH exposure, large-scale gene expression analysis resulted in characteristic molecular signatures for each PAH, and supervised analysis identified 1,183 outlier genes as a distinct molecular signature discerning PAHs from the normal control group. We identified 158 outlier genes as early predictive and surrogate markers for predicting each tested PAH by combination of two different multi-classification algorithms with 100% accuracy through a leave-one out cross-validation method. In conclusion, the characteristic gene expression signatures from a rat model system could be used as predictable and discernible gene-based biomarkers for the detection and prediction of PAHs, and these molecular markers may provide insights into the underlying mechanisms for genotoxicity of exposure to PAHs from environmental aspect.
[show abstract][hide abstract] ABSTRACT: The putative tumor suppressor, DBC1 (deleted in breast cancer-1), was recently found to negatively regulate SIRT1 in vitro and in vivo, but the mechanism whereby DBC1 regulates SIRT1 in liver cancer remains to be elucidated. In this study, it was found that although the expression of DBC1 and SIRT1 was not aberrantly regulated in a large cohort of human hepatocellular carcinoma (HCC) patients, these proteins were highly overexpressed in a subset of HCC tissues compared with surrounding non-cancer tissues. In liver cancer, DBC1 and SIRT1 were found to be positively correlated. Inactivation of DBC1 or SIRT1 reduced SNU-182 (a liver cancer cell line) proliferation as determined by MTT viability assays. Notably, although DBC1 functions as a negative regulator of SIRT1 in A549 lung cancer cells since it suppresses the deacetylase activity of the p53 protein, it did not affect the p53 deacetylase activity of SIRT1 in SNU-182 cells. Taken together, we conclude that DBC1 is associated with SIRT1 in HCC, but that it does not inhibit SIRT1.
[show abstract][hide abstract] ABSTRACT: Sirtuins are NAD(+) -dependent deacetylases and function in cellular metabolism, stress resistance and ageing. For Sirtuin7 (SIRT7), a role in ribosomal gene transcription is proposed, but its function in cancer has been unclear. In this study, we showed that SIRT7 expression was up-regulated in a large cohort of human hepatocellular carcinoma (HCC) patients. SIRT7 knockdown influenced the cell cycle and caused a significant increase of liver cancer cells to remain in the G1/S phase and to suppress growth. This treatment restored p21(WAF1/Cip1) , induced Beclin-1 and repressed cyclin D1. In addition, sustained suppression of SIRT7 reduced the in vivo tumor growth rate in a mouse xenograft model. To explore mechanisms in SIRT7 regulation, microRNA (miRNA) profiling was carried out. This identified five significantly down-regulated miRNAs in HCC. Bioinformatics analysis of target sites and ectopic expression in HCC cells evidenced miR-125a-5p and miR-125b to suppress SIRT7 and cyclin D1 expression and to induce p21(WAF1/Cip1) -dependent G1 cell cycle arrest. Furthermore, treatment of HCC cells with 5-aza-2'-deoxycytidine or ectopic expression of wild-type but not mutated p53 restored miR-125a-5p and miR-125b expression and inhibited tumor cell growth to suggest their regulation by promoter methylation and p53 activity. To evidence clinical significance of these findings, mutations in the DNA binding domain of p53 and promoter methylation of miR-125b were investigated. Four out of nine patients with induced SIRT7 carried mutations in p53 gene and one patient showed hypermethylation of miR-125b promoter region. Conclusion: Our findings suggest oncogenic potential of SIRT7 in hepatocarcinogenesis. A regulatory loop is proposed whereby SIRT7 inhibits transcriptional activation of p21(WAF1/Cip1) via repression of miR-125a-5p and miR-125b. This makes SIRT7 a promising target in cancer therapy. (HEPATOLOGY 2012.).
[show abstract][hide abstract] ABSTRACT: Histone deacetylase 2 (HDAC2) is crucial for embryonic development, affects cytokine signaling relevant for immune responses, and is often significantly overexpressed in solid tumors, but little is known of its role in human lung cancer. In this study, we demonstrated the aberrant expression of HDAC2 in lung cancer tissues and investigated oncogenic properties of HDAC2 in human lung cancer cell lines. HDAC2 inactivation resulted in regression of tumor cell growth and activation of cellular apoptosis via p53 and Bax activation and Bcl2 suppression. In cell cycle regulation, HDAC2 inactivation caused induction of p21WAF1/CIP1 expression, and simultaneously suppressed the expressions of cyclin E2, cyclin D1, and CDK2, respectively. Consequently, this led to the hypophosphorylation of pRb protein in G1/S transition and thereby inactivated E2F/DP1 target gene transcriptions of A549 cells. In addition, we demonstrated that HDAC2 directly regulated p21WAF1/CIP1 expression in a p53-independent manner. However, HDAC1 was not related to p21WAF1/CIP1 expression and tumorigenesis of lung cancer. Lastly, we observed that sustained-suppression of HDAC2 in A549 lung cancer cells attenuated in vitro tumorigenic properties and in vivo tumor growth of the mouse xenograft model. Taken together, we suggest that the aberrant regulation of HDAC2 and its epigenetic regulation of gene transcription in apoptosis and cell cycle components play an important role in the development of lung cancer.
Journal of Cellular Biochemistry 06/2012; 113(6):2167-77. · 3.06 Impact Factor
[show abstract][hide abstract] ABSTRACT: The trefoil factor family (TFF) of peptides, which are protease-resistant and have a strong affinity for mucins, play an important
role in gastrointestinal mucosal protection and restitution. Prior studies have indicated that dysregulation of TFF2 was associated
with cell migration, resistance to apoptosis, and gastric cancer invasion; however, the underlying mechanism associated with
these actions remains unclear. Thus, to investigate the relationship between TFF2 and carcinogenesis in gastric cancer, TFF2
expression was analyzed by Western blot analysis in nine selected gastric cancer tissues and immunohistochemical staining
was performed in paraffin-embedded samples from 157 gastric cancers. A reduced TFF2 expression was observed by Western blot
analysis in the gastric cancer tissues. However, there was no significant difference in the TFF2 expression according to clinical
and pathological parameters of the gastric cancers. To investigate the biological role of TFF2 in the development and progression
of gastric cancer, a TFF2 expression plasmid was constructed for in vitro experiments of function. Introduction of TFF2 cDNA into a gastric cancer cell line did not affect tumor cell growth, cell
migration or invasion. In conclusion, down-regulation of TFF2 in gastric cancer cells and restoration of TFF2 did not affect
the tumorigenic potential of gastric cancer cells in vitro. The loss of TFF2 expression might be an early event of the multi-step process of gastrocarcinogenesis and may play a limited
role in the mucosal protection of the normal gastric physiology.
KeywordsTFF2 expression-Gastric cancer-Cell growth-Motility-Invasion
Molecular and Cellular Toxicology 04/2012; 6(3):261-269. · 0.72 Impact Factor
[show abstract][hide abstract] ABSTRACT: Inappropriate activation of the Wnt signaling pathway has been repeatedly implicated in the tumorigenesis of colon, liver,
and gastric cancers. There is accumulating evidences that transcriptional factor 7 (TCF7; also called T cell factor 1) might also be one of the tumor suppressor genes in the Wnt pathway. We performed PCR-based sequencing analysis of the TCF7 gene in 234 alimentary tract cancers. The TCF7 mutants detected in this study were functionally analyzed after they were generated by a QuickChange site-directed mutagenesis
kit. We detected 7 somatic mutations in the TCF7 gene, including 4 missense, 2 frameshift, and one 28-bp deletion. In a yeast two-hybrid assay, most of the mutants showed
varying degrees of decreased binding to an amino-terminal enhancer of split (AES), a truncated form of Groucho-related protein
lacking WD40 repeats. To determine whether mutant TCF7 proteins had decreased DNA binding, we performed electrophoretic mobility
shift assays, and the 2 frameshift mutants were shown to have no DNA binding activity. Furthermore, luciferase reporter assays
revealed that TCF7 mutants in the presence of AES failed in the AES-dependent transcriptional repression of the reporter gene. In addition,
human embryonic kidney 293 cells transfected with TCF7 mutants expressed high levels of cyclin D1, up to 6 times more than cells transfected with wild-type TCF7. Therefore, the TCF7 mutations detected in this study seem to be “loss-of-function mutations“ caused by loss of TCF7 repressor activity through
decreased binding to Groucho-related protein and/or DNA, thereby contributing to neoplastic transformation by causing accumulation
of cylin D1.
-Wnt signaling pathway-Somatic mutations-Loss of heterozygosity-Alimentary tract cancers
Molecular and Cellular Toxicology 04/2012; 6(3):271-278. · 0.72 Impact Factor
[show abstract][hide abstract] ABSTRACT: Ubiquitin-binding histone deacetylase 6 (HDAC6) is uniquely endowed with tubulin deacetylase activity and plays an important role in the clearance of misfolded protein by autophagy. In cancer, HDAC6 has become a target for drug development due to its major contribution to oncogenic cell transformation. In the present study we show that HDAC6 expression was down-regulated in a large cohort of human hepatocellular carcinoma (HCC) patients, and that low expression of HDAC6 was significantly associated with poor prognosis of HCC patients in 5-year overall, disease-free, and recurrence-free survival. Notably, we observed that ectopic overexpression of HDAC6 suppressed tumor cell growth and proliferation in various liver cancer cells, and elicited increased LC3B-II conversion and autophagic vacuole formation without causing apoptotic cell death or cell cycle inhibition. In addition, the sustained overexpression of HDAC6 reduced the in vivo tumor growth rate in a mouse xenograft model. It was also found that HDAC6 mediated autophagic cell death by way of Beclin 1 and activation of the LC3-II pathway in liver cancer cells, and that HDAC6 overexpression activated c-Jun NH2-terminal kinase (JNK) and increased the phosphorylation of c-Jun. In contrast, the induction of Beclin 1 expression was blocked by SP600125 (a specific inhibitor of JNK) or by small interfering RNA directed against HDAC6. CONCLUSION: Our findings suggest that loss of HDAC6 expression in human HCCs and tumor suppression by HDAC6 occur by way of activation of caspase-independent autophagic cell death through the JNK/Beclin 1 pathway in liver cancer and, thus, that a novel tumor suppressor function mechanism involving HDAC6 may be amenable to nonepigenetic regulation.
[show abstract][hide abstract] ABSTRACT: Histone deacetylases (HDACs) are known to play a central role in the regulation of several cellular properties interlinked with the development and progression of cancer. Recently, HDAC1 has been reported to be overexpressed in hepatocellular carcinoma (HCC), but its biological roles in hepatocarcinogenesis remain to be elucidated. In this study, we demonstrated overexpression of HDAC1 in a subset of human HCCs and liver cancer cell lines. HDAC1 inactivation resulted in regression of tumor cell growth and activation of caspase-independent autophagic cell death, via LC3B-II activation pathway in Hep3B cells. In cell cycle regulation, HDAC1 inactivation selectively induced both p21(WAF1/Cip1) and p27(Kip1) expressions, and simultaneously suppressed the expression of cyclin D1 and CDK2. Consequently, HDAC1 inactivation led to the hypophosphorylation of pRb in G1/S transition, and thereby inactivated E2F/DP1 transcription activity. In addition, we demonstrated that HDAC1 suppresses p21(WAF1/Cip1) transcriptional activity through Sp1-binding sites in the p21(WAF1/Cip1) promoter. Furthermore, sustained suppression of HDAC1 attenuated in vitro colony formation and in vivo tumor growth in a mouse xenograft model. Taken together, we suggest the aberrant regulation of HDAC1 in HCC and its epigenetic regulation of gene transcription of autophagy and cell cycle components. Overexpression of HDAC1 may play a pivotal role through the systemic regulation of mitotic effectors in the development of HCC, providing a particularly relevant potential target in cancer therapy.
PLoS ONE 01/2012; 7(4):e34265. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Histone deacetylase 2 (HDAC2) is crucial for embryonic development, affects cytokine signaling relevant for immune responses and is often significantly overexpressed in solid tumors; but little is known about its role in human hepatocellular carcinoma (HCC). In this study, we showed that targeted-disruption of HDAC2 resulted in reduction of both tumor cell growth and de novo DNA synthesis in Hep3B cells. We then demonstrated that HDAC2 regulated cell cycle and that disruption of HDAC2 caused G1/S arrest in cell cycle. In G1/S transition, targeted-disruption of HDAC2 selectively induced the expression of p16(INK4A) and p21(WAF1/Cip1), and simultaneously suppressed the expression of cyclin D1, CDK4 and CDK2. Consequently, HDAC2 inhibition led to the down-regulation of E2F/DP1 target genes through a reduction in phosphorylation status of pRb protein. In addition, sustained suppression of HDAC2 attenuated in vitro colony formation and in vivo tumor growth in a mouse xenograft model. Further, we found that HDAC2 suppresses p21(WAF1/Cip1) transcriptional activity via Sp1-binding site enriched proximal region of p21(WAF1/Cip1) promoter. In conclusion, we suggest that the aberrant regulation of HDAC2 may play a pivotal role in the development of HCC through its regulation of cell cycle components at the transcription level providing HDAC2 as a relevant target in liver cancer therapy.
PLoS ONE 01/2011; 6(11):e28103. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Whole blood is one of the most easily accessible biofluids, and circulating leukocytes would include informative transcripts as a first line of immune defense for many disease processes. To demonstrate that transcriptomic responses of circulating blood cells reflect the exposure to environmental toxicants and the characteristic molecular signatures can discriminate and predict the type of toxicant at an early exposure time, we identified and validated characteristic gene expression profiles of rat whole blood after exposure to polycyclic aromatic hydrocarbons (PAHs). At an early exposure time point, conventional toxicological analysis including changes in the body and organ weight, histopathological examination, and blood biochemical analysis did not reflect any toxicant stresses. However, unsupervised gene expression analysis of blood cells resulted in a characteristic molecular signature for each toxicant. Further analysis of multiclassification suggested 220 genes as early detective and surrogate markers for predicting each PAH with 100% accuracy. These findings suggest that the blood expression signature could be used as a predictable and discernible surrogate marker for detection and prediction of PAHs, and the use of these molecular markers may be more widely implemented in combination with more traditional techniques for assessment and prediction of toxicity exposure to PAHs from an environmental aspect.
[show abstract][hide abstract] ABSTRACT: In a previous report we demonstrated that the transcriptomic response of liver tissue was specific to toxicants, and a characteristic molecular signature could be used as an early prognostic biomarker in rats. It is necessary to determine the transcriptomic response to toxicants in peripheral blood for application to the human system. Volatile organic compounds (VOCs) comprise a major group of pollutants which significantly affect the chemistry of the atmosphere and human health. In this study we identified and validated the specific molecular signatures of toxicants in rat whole blood as early predictors of environmental toxicants. VOCs (dichloromethane, ethylbenzene, and trichloroethylene) were administered to 11-week-old SD male rats after 48h of exposure, peripheral whole blood was subjected to expression profiling analysis. Unsupervised gene expression analysis resulted in a characteristic molecular signature for each toxicant, and supervised analysis identified 1,217 outlier genes as distinct molecular signatures discerning VOC exposure from healthy controls. Further analysis of multi-classification suggested 337 genes as early detective molecular markers for three VOCs with 100% accuracy. A large-scale gene expression analysis of a different VOC exposure animal model suggested that characteristic expression profiles exist in blood cells and multi-classification of this VOC-specific molecular signature can discriminate each toxicant at an early exposure time. This blood expression signature can thus be used as discernable surrogate marker for detection of biological responses to VOC exposure in an environment.
Toxicology and Applied Pharmacology 10/2010; 250(2):162-9. · 3.98 Impact Factor
[show abstract][hide abstract] ABSTRACT: Gastric carcinoma is the most common neoplasm in Southeast Asian populations and is the second leading cause of cancer death worldwide. Annexins are a family of cytosolic calcium and membrane binding proteins that have been implicated in a wide variety of cell functions. Recent studies have suggested that Annexin A10 (ANXA10), a member of the Annexin protein family, is down-regulated in specific types of cancer. However, the underlying molecular mechanisms of the dysregulation of ANXA10 remain to be elucidated. In the present study, to investigate the biological effects of ANXA10 on gastric carcinoma, aberrant expression of ANXA10 was evaluated by Western blot analysis, reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC), in gastric cancer tissues and cell lines. Decreased expression of ANXA10 was observed in five selected gastric cancer tissues compared to the normal surrounding mucosa. In the cancer cell lines, seven out of nine selected gastric cancer cell lines had no detectable ANXA10 by RT-PCR. Among these, when an ANXA10 expressing plasmid was introduced into MKN-1 cells, cell growth was suppressed and apoptosis augmented. The results of this study demonstrated that ANXA10 was aberrantly regulated in gastric carcinoma and suggests that down-regulation of ANXA10 might be involved in gastric carcinogenesis. In addition, ANXA10 may play a role, as a tumor suppressor, in the development and progression of gastric cancer.
[show abstract][hide abstract] ABSTRACT: The Wnt/beta-catenin signaling pathway regulates various aspects of development and plays important role in human carcinogenesis. Nemo-like kinase (NLK), which is mediator of Wnt/beta-catenin signaling pathway, phosphorylates T-cell factor/lymphoid enhancer factor (TCF/LEF) factor and inhibits interaction of beta-catenin/TCF complex. Although, NLK is known to be a tumor suppressor in Wnt/beta-catenin signaling pathway of colon cancer, the other events occurring downstream of NLK pathways in other types of cancer remain unclear. In the present study, we identified that expression of NLK was significantly up-regulated in the HCCs compared to corresponding normal tissues in five selected tissue samples. Immunohistochemical analysis showed significant over-expression of NLK in the HCCs. Targeted-disruption of NLK suppressed cell growth and arrested cell cycle transition. Suppression of NLK elicited anti-mitogenic properties of the Hep3B cells by simultaneous inhibition of cyclinD1 and CDK2. The results of this study suggest that NLK is aberrantly regulated in HCC, which might contribute to the mitogenic potential of tumor cells during the initiation and progression of hepatocellular carcinoma; this process appears to involve the induction of CDK2 and cyclin D1 and might provide a novel target for therapeutic intervention in patients with liver cancer.
Journal of Cellular Biochemistry 06/2010; 110(3):687-96. · 3.06 Impact Factor
[show abstract][hide abstract] ABSTRACT: The compound 3,4-methylenedioxymethamphetamine (MDMA or ecstasy) is a synthetic, psychoactive drug chemically similar to the stimulant methamphetamine and the hallucinogen mescaline. Accumulated data has revealed potential toxic effects associated with MDMA on brain serotonin and dopamine neurons in animal models. However, the relevance of these adverse effects on prenatal exposure to this drug remains unknown. In this study, we demonstrated that prenatal (F0) exposure to MDMA caused permanent large-scale transcriptional changes in the brains of the offspring (F1), especially in the cerebral cortex, by gene expression profiling analysis. The expression analysis of the brain of F1 pups, after maternal ingestion of MDMA (20 mg/kg MDMA), revealed significant transcriptional changes in both male and female pups. Supervised analysis resulted in the identification of 804 outlier genes in males and 1784 outlier genes in females as MDMA-associated genes in the F1 generation. Most of the functional categories of genes, among the outlier genes, were intracellular signaling pathways, including the MAPK signaling pathway, Wnt signaling pathway, and neuroactive ligand-receptor interaction pathway. Although these genes were affected by MDMA exposure in utero, their association with brain dysfunction requires further investigation. The results of this study suggest that prenatal MDMA exposure may affect the developing brain.
[show abstract][hide abstract] ABSTRACT: Hepatocellular carcinoma (HCC) is the third leading cause of cancer death worldwide. The number of cases of HCC has continued to increase in recent decades. Previous studies have suggested that S100P, a member of the S100P calcium-binding protein family, is aberrantly regulated in several malignant neoplasms. However, the underlying molecular mechanisms of the dysregulation of S100P remain to be elucidated. To investigate biological effects of S100P on hepatocarcinogenesis, aberrant expression of S100P was investigated by immunohistochemistry (IHC), Western blot analysis and reverse transcriptase-polymerase chain reaction (RT-PCR) in HCC tissues and cell lines. Endogenous expression of S100P was disrupted by the RNA interference-mediated protein knockdown method in the human Hep3B liver cancer cell line. Then, cell growth and cellular apoptosis were compared with control siRNA transfectants. The effects of S100P-silencing on the major components of cell cycle regulation were assessed by Western blot analysis. As results, elevated levels of S100P were observed in the HCC tissues compared to the corresponding normal tissues. Targeted disruption of S100P suppressed cell growth and augmented cellular apoptosis. In addition, inhibition of S100P resulted in the down-regulation of cyclinD1 and CDK2. In conclusion, this study showed over-expression of S100P in HCC. The aberrant regulation of S100P in HCC might activate cyclin D1 and CDK expression and contribute to the mitogenic potential of tumor cells during HCC carcinogenesis. These findings provide information that suggests new therapeutic strategies for the treatment of liver cancer.
International Journal of Oncology 12/2009; 35(6):1257-64. · 2.66 Impact Factor
[show abstract][hide abstract] ABSTRACT: The transforming growth factor receptor III (TGFbetaRIII) is the most abundant and essential TGF-beta binding protein that functions as a co-receptor with other receptors in TGF-beta signaling. In earlier studies, expression of TGFbetaRIII was reported to be decreased in a variety of human cancers. Functional assessment of TGFbetaRIII was performed in many previously studied cancers but not in hepatocellular carcinoma. Therefore, in this study, we investigated the expression and genetic alterations of TGFbetaRIII in hepatocellular carcinoma (HCC) by quantitative real-time PCR (qRT-PCR) and single-strand conformation polymorphism (SSCP) analysis. The qRT-PCR showed down-regulation of TGFbetaRIII in the tumor samples. To investigate whether genetic alterations mediated decreased expression of TGFbetaRIII, we performed mutation analysis of 67 human HCC tissues by SSCP and direct sequencing. We found five previously reported and one novel single nucleotide polymorphisms in exons 2, 3, 5, 13 and 14, but no mutations were detected. These polymorphisms were not associated with amino acid changes except for a base change found in exon 2 (TCC-->TTC, S15F). The loss of heterozygosity (LOH) analysis performed on 10 tumors and corresponding normal pairs, showed a low rate of LOH (2/10). The results of this study suggest that TGFbetaRIII is transcriptionally down-regulated in hepatocellular carcinoma. In addition, genetic alterations did not appear to be associated with the reduced expression level of TGFbetaRIII. To clarify the role of TGFbetaRIII in hepatocellular tumor development and progression, functional analysis is needed in future studies.