-
Yulan Cheng,
Zhe Jin,
Rachana Agarwal,
Ke Ma,
Jian Yang,
Soibrahim Ibrahim,
Alexandru V Olaru, Stefan David,
Hassan Ashktorab,
Duane T Smoot,
Mark D Duncan,
David F Hutcheon,
John M Abraham,
Stephen J Meltzer,
Yuriko Mori
[show abstract]
[hide abstract]
ABSTRACT: We previously reported frequent truncating mutations of the RNA-binding protein gene, La ribonucleoprotein domain family, member-7 (LARP7) in gastric cancers (GCs) with frequent microsatellite instability. LARP7 negatively regulates positive transcription elongation factor-b (p-TEFb) by binding to and stabilizing 7sk RNA. p-TEFb has been linked to proliferation and de-differentiation in various tissues. Therefore, we reasoned that loss of LARP7 may contribute to gastric tumorigenesis. In this study, we evaluated LARP7 mRNA expression in 18 GCs, their corresponding non-neoplastic gastric tissues (N(GC)), and 18 normal gastric tissues from healthy individuals (N(N)). We also assessed the effects of transient small interfering (siRNA)-mediated LARP7 knockdown in immortalized non-neoplastic gastric epithelial cells. LARP7 mRNA was significantly decreased in GCs (median 2.5) relative to N(N)s (median 14.9, P<0.01) as well as relative to their corresponding N(GC)s (median 8.1, P<0.01). Transfection of an siRNA directed against LARP7 (anti-LARP7 siRNA) into non-neoplastic gastric epithelial cells decreased 7sk levels by 72% relative to a control siRNA (P<0.01). Furthermore, anti-LARP7 siRNA transfection increased cell proliferation by 23% (P<0.01) and cell migration by 22% (P<0.001) relative to control siRNA transfection. Taken together, these findings suggest that LARP7 downregulation occurs early during gastric tumorigenesis and may promote gastric tumorigenesis via p-TEFb dysregulation.
Laboratory Investigation 04/2012; 92(7):1013-9. · 3.64 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: MicroRNAs (miRs) have recently emerged as a novel class of gene expression regulators. The number of studies documenting an altered miR expression pattern in cancer continues to expand rapidly. Critical information is continuously gained regarding how aberrantly expressed miRs contribute to carcinogenesis. Current studies provide evidence that analyses of miR expression patterns have potential clinical applications toward developing tumor biomarkers to identify the presence and dissemination of esophageal cancer, as well as to assess tumor chemosensitivity or radiosensitivity. The incidence of esophageal cancer is on the rise, and this disease continues to portend a poor prognosis. The current review addresses ways in which altered miR expression contributes to esophageal carcinogenesis, along with how recent discoveries may be applied clinically.
Current Opinion in Pharmacology 12/2011; 11(6):612-6. · 6.86 Impact Factor
-
Alexandru V Olaru,
Yulan Cheng,
Rachana Agarwal,
Jian Yang, Stefan David,
John M Abraham,
Wayne Yu,
John H Kwon,
Mark Lazarev,
Steven R Brant,
Michael R Marohn,
David F Hutcheon,
Noam Harpaz,
Stephen J Meltzer,
Yuriko Mori
[show abstract]
[hide abstract]
ABSTRACT: CpG island (CGI) hypermethylation at discrete loci is a prevalent cancer-promoting abnormality in sporadic colorectal carcinomas (S-CRCs). We investigated genome-wide CGI methylation in inflammatory bowel disease (IBD)-associated CRCs (IBD-CRCs).
Methylation microarray analyses were conducted on seven IBD-CRCs, 17 S-CRCs, and eight normal control colonic tissues from patients without CRC or IBD. CGI methylator phenotype (CIMP), a surrogate marker for widespread cancer-specific CGI hypermethylation, was examined in 30 IBD-CRCs and 43 S-CRCs.
The genome-wide CGI methylation pattern of IBD-CRCs was CIMP status-dependent. Based on methylation array data profiling of all autosomal loci, CIMP(+) IBD-CRCs grouped together with S-CRCs, while CIMP(-) IBD-CRCs grouped together with control tissues. CIMP(-) IBD-CRCs demonstrated less methylation than did age-matched CIMP(-) S-CRCs at autosomal CGIs (z-score -0.17 vs. 0.09, P = 3 × 10(-3)) and CRC-associated hypermethylation target CGIs (z-score -0.43 vs. 0.68, P = 1 × 10(-4)). Age-associated hypermethylation target CGIs were significantly overrepresented in CGIs that were hypermethylated in S-CRCs (P = 1 × 10(-192)), but not in CGIs that were hypermethylated in IBD-CRCs (P = 0.11). In contrast, KRAS mutation prevalence was similar between IBD-CRCs and S-CRCs. Notably, CIMP(+) prevalence was significantly higher in older than in younger IBD-CRC cases (50.0 vs. 4.2, P = 0.02), but not in S-CRC cases (9.7 vs. 16.7, P = 0.92).
Cancer-specific CGI hypermethylation and age-associated CGI hypermethylation are diminished in IBD-CRCs relative to S-CRCs, while the KRAS mutation rate is comparable between these cancers. CGI hypermethylation appears to play only a minor role in IBD-associated carcinogenesis. We speculate that aging, rather than inflammation per se, promotes CIMP(+) CRCs in IBD patients.
Inflammatory Bowel Diseases 08/2011; 18(4):641-8. · 4.86 Impact Factor
-
Mohammed Orloff,
Charissa Peterson,
Xin He,
Shireen Ganapathi,
Brandie Heald,
Yi-ran Yang,
Gurkan Bebek,
Todd Romigh,
Jee Hoon Song,
Wenjing Wu, Stefan David,
Yulan Cheng,
Stephen J Meltzer,
Charis Eng
[show abstract]
[hide abstract]
ABSTRACT: Barrett esophagus (BE) occurs in 1% to 10% of the general population and is believed to be the precursor of esophageal adenocarcinoma (EAC). The incidence of EAC has increased 350% in the last 3 decades without clear etiology. Finding predisposition genes may improve premorbid risk assessment, genetic counseling, and management. Genome-wide multiplatform approaches may lead to the identification of genes important in BE/EAC development.
To identify risk alleles or mutated genes associated with BE/EAC.
Model-free linkage analyses of 21 concordant-affected sibling pairs with BE/EAC and 11 discordant sibling pairs (2005-2006). Significant germline genomic regions in independent prospectively accrued series of 176 white patients with BE/EAC and 200 ancestry-matched controls (2007-2010) were validated and fine mapped. Integrating data from these significant genomic regions with somatic gene expression data from 19 BE/EAC tissues yielded 12 "priority" candidate genes for mutation analysis (2010). Genes that showed mutations in cases but not in controls were further screened in an independent prospectively accrued validation series of 58 cases (2010).
Identification of germline mutations in genes associated with BE/EAC cases. Functional interrogation of the most commonly mutated gene.
Three major genes, MSR1, ASCC1, and CTHRC1 were associated with BE/EAC (all P < .001). In addition, 13 patients (11.2%) with BE/EAC carried germline mutations in MSR1, ASCC1, or CTHRC1. MSR1 was the most frequently mutated, with 8 of 116 (proportion, 0.069; 95% confidence interval [CI], 0.030-0.130; P < .001) cases with c.877C>T (p.R293X). An independent validation series confirmed germline MSR1 mutations in 2 of 58 cases (proportion, 0.035; 95% CI, 0.004-0.120; P = .09). MSR1 mutation resulted in CCND1 up-regulation in peripheral-protein lysate. Immunohistochemistry of BE tissues in MSR1-mutation carriers showed increased nuclear expression of CCND1.
MSR1 was significantly associated with the presence of BE/EAC in derivation and validation samples, although it was only present in a small percentage of the cases.
JAMA The Journal of the American Medical Association 07/2011; 306(4):410-9. · 30.03 Impact Factor
-
Tetsuo Ito,
Fumiaki Sato,
Takatsugu Kan,
Yulan Cheng, Stefan David,
Rachana Agarwal,
Bogdan C. Paun,
Zhe Jin,
Alexandru V. Olaru,
James P. Hamilton,
Florin M. Selaru,
Jian Yang,
Nobutoshi Matsumura,
Kazuharu Shimizu,
John M. Abraham,
Yutaka Shimada,
Yuriko Mori,
Stephen J. Meltzer
[show abstract]
[hide abstract]
ABSTRACT: Polo-like kinase 1 (PLK1) is overexpressed in various human cancers. However, the biological functions and the post-transcriptional regulations of PLK1 in esophageal cancer (EC) are still unknown. The purposes of our study are to determine whether PLK1 can be a molecular target of EC therapy and to identify a microRNA (miRNA) targeting PLK1. We performed loss-of-function and gain-of-function experiments regarding cell proliferation, cell cycle, apoptosis, in vivo tumor formation and luciferase reporter assays, using siRNAs against PLK1 and miRNA. PLK1 protein was expressed in all 11 EC cell lines, but not in normal esophageal epithelial cells (HEEpiC). Knockdown of PLK1 in EC cells induced G2/M arrest (p < 0.001) in cell cycle assay and reduced cell proliferation (p = 0.019) and tumor formation ability in vivo (p < 0.0001). MiR-593*, identified as a miRNA targeting PLK1 by a database search, was less expressed especially in six EC cell lines than HEEpiC cells. Moreover, miR-593* expression level was inversely correlated with PLK1 mRNA level in 48 clinical tissue specimens of EC (p = 0.006). Introduction of synthetic miR-593* suppressed PLK1 expression by 69–73%, reduced cell proliferation (p = 0.008) and increased cell proportion of G2/M phase (p = 0.01) in HSA/c (an EC cells), whereas a miR-593* inhibitor upregulated PLK1 expression by 11–55%. Additionally, luciferase assay demonstrated that miR-593* interacted two binding sites in the PLK1 3′-UTR and reduced 56.8–71.5% of luciferase activity by degrading luciferase mRNA in HSA/c cells. In conclusion, PLK1 is post-transcriptionally regulated by miR-593* and could be a promising molecular target for EC treatment.
International Journal of Cancer 03/2011; 129(9):2134 - 2146. · 5.44 Impact Factor
-
Alexandru V Olaru,
Florin M Selaru,
Yuriko Mori,
Christine Vazquez, Stefan David,
Bogdan Paun,
Yulan Cheng,
Zhe Jin,
Jian Yang,
Rachana Agarwal,
John M Abraham,
Themistocles Dassopoulos,
Mary Harris,
Theodore M Bayless,
John Kwon,
Noam Harpaz,
Ferenc Livak,
Stephen J Meltzer
[show abstract]
[hide abstract]
ABSTRACT: Patients with inflammatory bowel disease (IBD) are at increased risk of developing colorectal cancer. Aberrant microRNA (miR) expression has been linked to carcinogenesis; however, no reports document a relationship between IBD-related neoplasia (IBDN) and altered miR expression. In the current study we sought to identify specific miR dysregulation along the normal-inflammation-cancer axis.
miR microarrays and quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) were used to detect dysregulated miRs. Receiver operating characteristic curve analysis was employed to test for potential usefulness of miR-31 as a disease marker of IBDNs. In silico prediction analysis, Western blot, and luciferase activity measurement were employed for target identification.
Several dysregulated miRs were identified between chronically inflamed mucosae and dysplasia arising in IBD. MiR-31 expression increases in a stepwise fashion during progression from normal to IBD to IBDN and accurately discriminated IBDNs from normal or chronically inflamed tissues in IBD patients. Finally, we identified factor inhibiting hypoxia inducible factor 1 as a direct target of miR-31.
Our study reveals specific miR dysregulation as chronic inflammation progresses to dysplasia. MiR-31 expression levels increase with disease progression and accurately discriminates between distinct pathological entities that coexist in IBD patients. The novel effect of miR-31 on regulating factor inhibiting hypoxia inducible factor 1 expression provides a new insight on the pathogenesis of IBDN.
Inflammatory Bowel Diseases 01/2011; 17(1):221-31. · 4.86 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Gastric cancer is one of the most common neoplasias in the world and remains an important cause of cancer-related mortality. Vast resources have been invested in the study of the molecular events driving the development and progression of gastric tumors. Gastric cancer is known to result from an interaction between host and environmental factors. The present review will discuss the most how genetic and epigenetic changes contribute to gastric carcinogenesis and their potential for developing novel diagnostic and therapeutic tools.
Cancer biomarkers: section A of Disease markers 01/2011; 9(1-6):493-507. · 1.08 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The study of molecular processes driving human neoplasia development is achieving critical gains in terms of better detection
and treatment. Current medicine already benefits from discovering genetic signatures of distinct cancers, and therapies have
become more specifically targeted to the molecular aberrations defining particular cancers (e.g.: chronic myelogenous leukemia
is now diagnosed by detecting the t(9;22)(q34;q11) translocation, and therapy is based on inhibitors of the aberrant bcr-abl kinase). Epigenetic processes complement the genetic determinants of the cellular phenotype, and their study is of great
interest for cancer researchers. The primary physiologic role of epigenetics is to govern cellular differentiation. Epigenetics
have particular importance in organogenesis and also in maintaining the proper phenotypic profile of each cell in distinct
organs and systems. The vast majority of current studies address DNA methylation changes pertinent to different tumor types.
The global hypomethylation occurring in cancer results in genetic instability and may trigger enhanced expression of particular
oncogenes. In contrast, aberrant promoter hypermethylation may reduce the expression of proteins that are critical for tissue
homeostasis. This mechanism may reduce the expression of important tumor suppressor genes or the level of proteins critically
involved in DNA maintenance and repair, cellular adhesion and intracellular signaling. Apart from methylation, neoplasia related
perturbations were identified in virtually all of the epigenetic machinery. Proteins controlling DNA conformation (such as
histone– modifying enzymes, or components of ATP-dependent remodeling and poly-ADP ribosylation) show reduced expression or
activity in several distinct tumor types, providing evidence that epigenetics are critically involved in cancer development.
The dynamic profile of epigenetic changes provides valuable background for clinical applications. Based on the particular
epigenetic signatures described for different tumors, current studies focus on the development of epigenetic tests not only
to diagnose cancer in early stages including pre-invasive disease, but also to identify patients at risk for tumor development.
In addition, neoplasia-related epigenetic changes open a new therapeutic approach in human cancers, with drugs that undergo
or have already passed clinical trials. Epigenetics are therefore emerging as a promising field for both diagnostic and therapeutic
approaches of human neoplasia and pre-invasive disease.
12/2010: pages 41-63;
-
Alexandru V. Olaru MD,
Florin M. Selaru MD,
PhD Yuriko Mori MD,
Christine Vazquez BSc,
Stefan David MD,
Bogdan Paun MD,
Yulan Cheng MD,
Zhe Jin MD,
Jian Yang MS,
Rachana Agarwal PhD, [......],
Jian Yang,
Rachana Agarwal,
John M. Abraham,
Themistocles Dassopoulos,
Mary Harris,
Theodore M. Bayless,
John Kwon,
Noam Harpaz,
Ferenc Livak,
Stephen J. Meltzer
[show abstract]
[hide abstract]
ABSTRACT: Background:Patients with inflammatory bowel disease (IBD) are at increased risk of developing colorectal cancer. Aberrant microRNA (miR) expression has been linked to carcinogenesis; however, no reports document a relationship between IBD-related neoplasia (IBDN) and altered miR expression. In the current study we sought to identify specific miR dysregulation along the normal–inflammation–cancer axis.Methods:miR microarrays and quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) were used to detect dysregulated miRs. Receiver operating characteristic curve analysis was employed to test for potential usefulness of miR-31 as a disease marker of IBDNs. In silico prediction analysis, Western blot, and luciferase activity measurement were employed for target identification.Results:Several dysregulated miRs were identified between chronically inflamed mucosae and dysplasia arising in IBD. MiR-31 expression increases in a stepwise fashion during progression from normal to IBD to IBDN and accurately discriminated IBDNs from normal or chronically inflamed tissues in IBD patients. Finally, we identified factor inhibiting hypoxia inducible factor 1 as a direct target of miR-31.Conclusions:Our study reveals specific miR dysregulation as chronic inflammation progresses to dysplasia. MiR-31 expression levels increase with disease progression and accurately discriminates between distinct pathological entities that coexist in IBD patients. The novel effect of miR-31 on regulating factor inhibiting hypoxia inducible factor 1 expression provides a new insight on the pathogenesis of IBDN. (Inflamm Bowel Dis 2011;)
Inflammatory Bowel Diseases 12/2010; 17(1):221 - 231. · 4.86 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Drug-induced liver injury (DILI) is common and nearly all classes of medications can cause liver disease. Most cases of DILI are benign, and improve after drug withdrawal. It is important to recognize and remove the offending agent as quickly as possible to prevent the progression to chronic liver disease and/or acute liver failure. There are no definite risk factors for DILI, but pre-existing liver disease and genetic susceptibility may predispose certain individuals. Although most patients have clinical symptoms that are identical to other liver diseases, some patients may present with symptoms of systemic hypersensitivity. Treatment of drug and herbal-induced liver injury consists of rapid drug discontinuation and supportive care targeted to alleviate unwanted symptoms.
US gastroenterology & hepatology review. 01/2010; 6:73-80.
-
[show abstract]
[hide abstract]
ABSTRACT: Epigenetics refers to heritable changes in gene expression that are, unlike mutations, not attributable to alterations in DNA sequence. Two predominant epigenetic mechanisms are DNA methylation and histone modification. Epigenetic regulation of gene expression has emerged as a fundamental pathway in the pathogenesis of numerous malignancies, including cancers of the digestive system-in fact, many exciting discoveries in epigenetics have come out of the study of cancers of the gastrointestinal tract and hepatobiliary tree. Epigenetic modifications of DNA in cancer and precancerous lesions offer the promise of novel biomarkers for early cancer detection, prediction, prognosis, and response to treatment. Furthermore, reversal of epigenetic changes represents a potential target of novel therapeutic strategies and medication design. In the future, innovative diagnostic tests and treatment regimens will likely be based on epigenetic mechanisms and be incorporated into the gastroenterologist's practice.
The American Journal of Gastroenterology 09/2009; 104(8):1910-2. · 7.28 Impact Factor
-
Zhe Jin,
Yulan Cheng,
Wen Gu,
Yingye Zheng,
Fumiaki Sato,
Yuriko Mori,
Alexandru V Olaru,
Bogdan C Paun,
Jian Yang,
Takatsugu Kan, [......],
Jean Wang,
Marcia Irene Canto,
Achyut Bhattacharyya,
Mark A Nelson,
Paul D Wagner,
Yvonne Romero,
Kenneth K Wang,
Ziding Feng,
Richard E Sampliner,
Stephen J Meltzer
[show abstract]
[hide abstract]
ABSTRACT: Esophageal adenocarcinoma risk in Barrett's esophagus (BE) is increased 30- to 125-fold versus the general population. Among all BE patients, however, neoplastic progression occurs only once per 200 patient-years. Molecular biomarkers are therefore needed to risk-stratify patients for more efficient surveillance endoscopy and to improve the early detection of progression. We therefore performed a retrospective, multicenter, double-blinded validation study of eight BE progression prediction methylation biomarkers. Progression or nonprogression were determined at 2 years (tier 1) and 4 years (tier 2). Methylation was assayed in 145 nonprogressors and 50 progressors using real-time quantitative methylation-specific PCR. Progressors were significantly older than nonprogressors (70.6 versus 62.5 years; P < 0.001). We evaluated a linear combination of the eight markers, using coefficients from a multivariate logistic regression analysis. Areas under the ROC curve (AUC) were high in the 2-year, 4-year, and combined data models (0.843, 0.829, and 0.840; P < 0.001, <0.001, and <0.001, respectively). In addition, even after rigorous overfitting correction, the incremental AUCs contributed by panels based on the 8 markers plus age versus age alone were substantial (Delta-AUC = 0.152, 0.114, and 0.118, respectively) in all 3 models. A methylation biomarker-based panel to predict neoplastic progression in BE has potential clinical value in improving both the efficiency of surveillance endoscopy and the early detection of neoplasia.
Cancer Research 05/2009; 69(10):4112-5. · 7.86 Impact Factor
-
Takatsugu Kan,
Fumiaki Sato,
Tetsuo Ito,
Nobutoshi Matsumura, Stefan David,
Yulan Cheng,
Rachana Agarwal,
Bogdan C Paun,
Zhe Jin,
Alexandru V Olaru,
Florin M Selaru,
James P Hamilton,
Jian Yang,
John M Abraham,
Yuriko Mori,
Stephen J Meltzer
[show abstract]
[hide abstract]
ABSTRACT: Barrett's esophagus (BE) is a highly premalignant disease that predisposes to the development of esophageal adenocarcinoma (EAC); however, the involvement of microRNAs (miRs) in BE-EAC carcinogenic progression is not known.
Esophageal cultured cells (HEEpiC, QhTRT, ChTRT, GihTRT, and OE-33) and esophageal tissues (22 normal epithelia, 24 BE, and 22 EAC) were studied. MiR microarrays and quantitative reverse-transcription polymerase chain reaction (RT-PCR) were employed to explore and verify differentially expressed miRs. Quantitative genomic PCR was performed to study copy number variation at the miR-106b-25 polycistron and MCM7 gene locus on chromosome 7q22.1. In vitro cell proliferation, cell cycle, and apoptosis assays and in vivo tumorigenesis experiments were performed to elucidate biologic effects of the miR-106b-25 polycistron. Western blotting and luciferase assays were performed to confirm direct messenger RNA (mRNA) targeting by the miR-106b-25 polycistron.
The miR-106b-25 polycistron exerted potential proliferative, antiapoptotic, cell cycle-promoting effects in vitro and tumorigenic activity in vivo. MiRs-93 and -106b targeted and inhibited p21, whereas miR-25 targeted and inhibited Bim. This polycistron was upregulated progressively at successive stages of neoplasia, in association with genomic amplification and overexpression of MCM7. In addition, miRs-93 and -106b decreased p21 mRNA, whereas miR-25 did not alter Bim mRNA, suggesting the following discrete miR effector mechanisms: (1) for p21, mRNA degradation; (2) for Bim, translational inhibition.
The miR-106b-25 polycistron is activated by genomic amplification and is potentially involved in esophageal neoplastic progression and proliferation via suppression of 2 target genes: p21 and Bim.
Gastroenterology 05/2009; 136(5):1689-700. · 11.68 Impact Factor
-
Florin M Selaru,
Alexandru V Olaru,
Takatsugu Kan, Stefan David,
Yulan Cheng,
Yuriko Mori,
Jian Yang,
Bogdan Paun,
Zhe Jin,
Rachana Agarwal, [......],
Hector Alvarez,
Perumal Vivekanandan,
Wayne Yu,
Anirban Maitra,
Michael Torbenson,
Paul J Thuluvath,
Gregory J Gores,
Nicholas F LaRusso,
Ralph Hruban,
Stephen J Meltzer
[show abstract]
[hide abstract]
ABSTRACT: Cholangiocarcinomas (CCAs) are aggressive cancers, with high mortality and poor survival rates. Only radical surgery offers patients some hope of cure; however, most patients are not surgical candidates because of late diagnosis secondary to relatively poor accuracy of diagnostic means. MicroRNAs (miRs) are involved in every cancer examined, but they have not been evaluated in primary CCA. In this study, miR arrays were performed on five primary CCAs and five normal bile duct specimens (NBDs). Several miRs were dysregulated and miR-21 was overexpressed in CCAs. miR-21 differential expression in these 10 specimens was verified by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). To validate these findings, qRT-PCR for miR-21 was then performed on 18 additional primary CCAs and 12 normal liver specimens. MiR-21 was 95% sensitive and 100% specific in distinguishing between CCA and normal tissues, with an area under the receiver operating characteristic curve of 0.995. Inhibitors of miR-21 increased protein levels of programmed cell death 4 (PDCD4) and tissue inhibitor of metalloproteinases 3 (TIMP3). Notably, messenger RNA levels of TIMP3 were significantly lower in CCAs than in normals. Conclusions: MiR-21 is overexpressed in human CCAs. Furthermore, miR-21 may be oncogenic, at least in part, by inhibiting PDCD4 and TIMP3. Finally, these data suggest that TIMP3 is a candidate tumor suppressor gene in the biliary tree.
Hepatology 03/2009; 49(5):1595-601. · 11.66 Impact Factor
-
Florin M. Selaru,
Alexandru V. Olaru,
Takatsugu Kan, Stefan David,
Yulan Cheng,
Yuriko Mori,
Jian Yang,
Bogdan Paun,
Zhe Jin,
Rachana Agarwal, [......],
Hector Alvarez,
Perumal Vivekanandan,
Wayne Yu,
Anirban Maitra,
Michael Torbenson,
Paul J. Thuluvath,
Gregory J. Gores,
Nicholas F. LaRusso,
Ralph Hruban,
Stephen J. Meltzer
[show abstract]
[hide abstract]
ABSTRACT: Cholangiocarcinomas (CCAs) are aggressive cancers, with high mortality and poor survival rates. Only radical surgery offers patients some hope of cure; however, most patients are not surgical candidates because of late diagnosis secondary to relatively poor accuracy of diagnostic means. MicroRNAs (miRs) are involved in every cancer examined, but they have not been evaluated in primary CCA. In this study, miR arrays were performed on five primary CCAs and five normal bile duct specimens (NBDs). Several miRs were dysregulated and miR-21 was overexpressed in CCAs. miR-21 differential expression in these 10 specimens was verified by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). To validate these findings, qRT-PCR for miR-21 was then performed on 18 additional primary CCAs and 12 normal liver specimens. MiR-21 was 95% sensitive and 100% specific in distinguishing between CCA and normal tissues, with an area under the receiver operating characteristic curve of 0.995. Inhibitors of miR-21 increased protein levels of programmed cell death 4 (PDCD4) and tissue inhibitor of metalloproteinases 3 (TIMP3). Notably, messenger RNA levels of TIMP3 were significantly lower in CCAs than in normals. Conclusions: MiR-21 is overexpressed in human CCAs. Furthermore, miR-21 may be oncogenic, at least in part, by inhibiting PDCD4 and TIMP3. Finally, these data suggest that TIMP3 is a candidate tumor suppressor gene in the biliary tree. (HEPATOLOGY 2009.)
Hepatology 02/2009; 49(5):1595 - 1601. · 11.66 Impact Factor
-
Takatsugu Kan, Fumiaki Sato,
Tetsuo Ito,
Nobutoshi Matsumura, Stefan David,
Yulan Cheng,
Rachana Agarwal,
Bogdan C. Paun,
Zhe Jin,
Alexandru V. Olaru,
Florin M. Selaru,
James P. Hamilton
Gastroenterology 01/2009; 136(5):1689-1700. · 11.68 Impact Factor
-
Rachana Agarwal,
Yuriko Mori,
Yulan Cheng,
Zhe Jin,
Alexandru V Olaru,
James P Hamilton, Stefan David,
Florin M Selaru,
Jian Yang,
John M Abraham,
Elizabeth Montgomery,
Patrice J Morin,
Stephen J Meltzer
[show abstract]
[hide abstract]
ABSTRACT: Claudins are membrane proteins that play critical roles in tight junction (TJ) formation and function. Members of the claudin gene family have been demonstrated to be aberrantly regulated, and to participate in the pathogenesis of various human cancers. In the present study, we report that claudin-11 (CLDN11) is silenced in gastric cancer via hypermethylation of its promoter region.
Levels of CLDN11 methylation and mRNA expression were measured in primary gastric cancer tissues, noncancerous gastric mucosae, and cell lines of gastric origin using quantitative methylation-specific PCR (qMSP) and quantitative reverse transcriptase-PCR (qRT-PCR), respectively. Analyses of paired gastric cancers and adjacent normal gastric tissues revealed hypermethylation of the CLDN11 promoter region in gastric cancers, and this hypermethylation was significantly correlated with downregulation of CLDN11 expression vs. normal tissues. The CLDN11 promoter region was also hypermethylated in all gastric cancer cell lines tested relative to immortalized normal gastric epithelial cells. Moreover, CLDN11 mRNA expression was inversely correlated with its methylation level. Treatment of CLDN11-nonexpressing gastric cancer cells with 5-aza-2'-deoxycytidine restored CLDN11 expression. Moreover, siRNA-mediated knockdown of CLDN11 expression in normal gastric epithelial cells increased their motility and invasiveness.
These data suggest that hypermethylation of CLDN11, leading to downregulated expression, contributes to gastric carcinogenesis by increasing cellular motility and invasiveness. A further understanding of the mechanisms underlying the role of claudin proteins in gastric carcinogenesis will likely help in the identification of novel approaches for diagnosis and therapy of gastric cancer.
PLoS ONE 01/2009; 4(11):e8002. · 4.09 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Tachykinin-1 (TAC1) is the precursor protein for neuroendocrine peptides, including substance P, and is centrally involved in gastric secretion, motility, mucosal immunity, and cell proliferation. Here we report aberrant silencing of TAC1 in gastric cancer (GC) by promoter hypermethylation. TAC1 methylation and mRNA expression in 47 primary GCs and 41 noncancerous gastric mucosae (NLs) were analyzed by utilizing real-time quantitative PCR-based assays. TAC1 methylation was more prevalent in GCs than in NLs: 21 (45%) of 47 GCs versus 6 (15%) of 41 NLs (p<0.01). Microsatellite instability was also associated with TAC1 methylation in GCs. There was no significant association between TAC1 methylation and age, gender, stage, histological differentiation, or the presence of Helicobacter pylori. TAC1 mRNA was markedly downregulated in GCs relative to NLs. 5-Aza-2'-deoxycytidine-induced demethylation of the TAC1 promoter resulted in TAC1 mRNA upregulation. Further studies are indicated to elucidate the functional involvement of TAC1 in gastric carcinogenesis.
Biochemical and Biophysical Research Communications 12/2008; 378(3):605-9. · 2.48 Impact Factor
-
Zhe Jin,
Yulan Cheng,
Alexandru Olaru,
Takatsugu Kan,
Jian Yang,
Bogdan Paun,
Tetsuo Ito,
James P Hamilton, Stefan David,
Rachana Agarwal,
Florin M Selaru,
Fumiaki Sato,
John M Abraham,
David G Beer,
Yuriko Mori,
Yutaka Shimada,
Stephen J Meltzer
[show abstract]
[hide abstract]
ABSTRACT: Although the CDH13 gene has been shown to undergo epigenetic silencing by promoter methylation in many types of tumors, hypermethylation of this gene in Barrett's-associated esophageal adenocarcinogenesis has not been studied. Two hundred fifty-nine human esophageal tissues were therefore examined for CDH13 promoter hypermethylation by real-time methylation-specific PCR. CDH13 hypermethylation showed discriminative receiver-operator characteristic curve profiles, sharply demarcating esophageal adenocarcinoma (EAC) from esophageal squamous cell carcinoma (ESCC) and normal esophagus (NE) (p < 0.0001). CDH13 normalized methylation values (NMV) were significantly higher in Barrett's esophagus (BE), dysplastic BE (D) and EAC than in NE (p < 0.0000001). CDH13 hypermethylation frequency was 0% in NE but increased early during neoplastic progression, rising to 70% in BE, 77.5% in D and 76.1% in EAC. Both CDH13 hypermethylation frequency and its mean NMV were significantly higher in BE with than without accompanying EAC. In contrast, only 5 (19.2%) of 26 ESCCs exhibited CDH13 hypermethylation. Furthermore, both CDH13 hypermethylation frequency and its mean NMV were significantly higher in EAC than in ESCC, as well as in BE or D vs. ESCC. Interestingly, mean CDH13 NMV was significantly lower in short-segment than in long-segment BE, a known clinical risk factor for neoplastic progression. Similarly, BE segment length was significantly lower in specimens with unmethylated than with methylated CDH13 promoters. 5-aza-2'-deoxycytidine treatment of OE33 EAC and KYSE220 ESCC cells reduced CDH13 methylation and increased CDH13 mRNA expression. These findings suggest that hypermethylation of CDH13 is a common, tissue-specific event in human EAC, occurs early during BE-associated neoplastic progression, and correlates with known clinical neoplastic progression risk factors.
International Journal of Cancer 08/2008; 123(10):2331-6. · 5.44 Impact Factor
-
Tetsuo Ito,
Yutaka Shimada,
Takatsugu Kan, Stefan David,
Yulan Cheng,
Yuriko Mori,
Rachana Agarwal,
Bogdan Paun,
Zhe Jin,
Alexandru Olaru,
James P Hamilton,
Jian Yang,
John M Abraham,
Stephen J Meltzer,
Fumiaki Sato
[show abstract]
[hide abstract]
ABSTRACT: Human pituitary tumor-transforming 1 (PTTG1)/securin is a putative oncoprotein that is overexpressed in various tumor types. However, the involvement of PTTG1 in gastrointestinal cancer development and progression remains unclear. In this study, we investigated the clinical significance and biological effects of PTTG1 in esophageal squamous cell carcinoma (ESCC). Immunohistochemical studies performed on 113 primary ESCC specimens revealed a high prevalence of PTTG1 overexpression (60.2%), which was significantly associated with lymph node metastasis (regional, P = 0.042; distant, P = 0.005), advanced tumor stage (P = 0.028), and poorer overall survival (P = 0.017, log-rank test; P = 0.044, Cox proportional hazard model). Eleven ESCC cell lines expressed PTTG1 protein at levels 2.4 to 6.6 times higher than those in normal esophageal epithelial cells (HEEpiC). PTTG1 protein expression was confined to the nucleus in HEEpiC cells but present in both the cytoplasm and nucleus in ESCC cells. Two small interfering RNAs (siRNA) inhibited PTTG1 mRNA and protein expression in three ESCC cell lines by 77% to 97%. In addition, PTTG1 down-regulation by these siRNAs significantly reduced cell motility in all three ESCC cell lines (P < 0.01) in vitro, as well as popliteal lymph node metastases of ESCC cells in nude mice (P = 0.020). Global gene expression profiling suggested that several members of the Ras and Rho gene families, including RRAS, RHOG, ARHGAP1, and ARHGADIA, represented potential downstream genes in the PTTG1 pathway. Taken together, these findings suggest that PTTG1 overexpression promotes cell motility and lymph node metastasis in ESCC patients, leading to poorer survival. Thus, PTTG1 constitutes a potential biomarker and therapeutic target in ESCCs with lymph node metastases.
Cancer Research 05/2008; 68(9):3214-24. · 7.86 Impact Factor
