Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Carriers of mutations in the cell cycle checkpoint protein kinase ataxia telangiectasia mutated (ATM), which represent 1-2% of the general population, have an increased risk of breast cancer. However, experimental evidence that ATM deficiency contributes to human breast carcinogenesis is lacking. We report here that in MCF-10A and MCF-12A cells, which are well established normal human mammary gland epithelial cell models, partial or almost complete stable ATM silencing or pharmacological inhibition resulted in cellular transformation, genomic instability, and formation of dysplastic lesions in NOD/SCID mice. These effects did not require the activity of exogenous DNA-damaging agents and were preceded by an unsuspected and striking increase in cell proliferation also observed in primary human mammary gland epithelial cells. Increased proliferation correlated with a dramatic, transient, and proteasome-dependent reduction of p21(WAF1/CIP1) and p27(KIP1) protein levels, whereas little or no effect was observed on p21(WAF1/CIP1) or p27(KIP1) mRNAs. p21(WAF1/CIP1) silencing also increased MCF-10A cell proliferation, thus identifying p21(WAF1/CIP1) down-regulation as a mediator of the proliferative effect of ATM inhibition. Our findings provide the first experimental evidence that ATM is a human breast tumor suppressor. In addition, they mirror the sensitivity of ATM tumor suppressor function and unveil a new mechanism by which ATM might prevent human breast tumorigenesis, namely a direct inhibitory effect on the basal proliferation of normal mammary epithelial cells.
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PMID:Ataxia telangiectasia mutated (ATM) inhibition transforms human mammary gland epithelial cells. 2017 72

Arsenic is a known human bladder carcinogen; however, the mechanisms underlying arsenical-induced bladder carcinogenesis are not understood. Previous research has demonstrated that exposure of a nontumorigenic human urothelial cell line, UROtsa, to 50 nM monomethylarsonous acid (MMA(III)) for 52 weeks resulted in malignant transformation. To focus research on the early mechanistic events leading to MMA(III)-induced malignancy, the goal of this research was to resolve the critical period in which continuous MMA(III) exposure (50 nM) induces the irreversible malignant transformation of UROtsa cells. An increased growth rate of UROtsa cells results after 12 weeks of MMA(III) exposure. Anchorage-independent growth occurred after 12 weeks with a continued increase in colony formation when 12-week exposed cells were cultured for an additional 12 or 24 weeks without MMA(III) exposure. UROtsa cells as early as 12 weeks MMA(III) exposure were tumorigenic in severe combined immunodeficiency mice with tumorigenicity increasing when 12-week exposed cells were cultured for an additional 12 or 24 weeks in the absence of MMA(III) exposure. To assess potential underlying mechanisms associated with the early changes that occur during MMA(III)-induced malignancy, DNA methylation was assessed in known target gene promoter regions. Although DNA methylation remains relatively unchanged after 12 weeks of exposure, aberrant DNA methylation begins to emerge after an additional 12 weeks in culture and continues to increase through 24 weeks in culture without MMA(III) exposure, coincident with the progression of a tumorigenic phenotype. Overall, these data demonstrate that 50 nM MMA(III) is capable of causing irreversible malignant transformation in UROtsa cells after 12 weeks of exposure. Having resolved an earlier timeline in which MMA(III)-induced malignant transformation occurs in UROtsa cells will allow for mechanistic studies focused on the critical biological changes taking place within these cells prior to 12 weeks of exposure, providing further evidence about potential mechanisms of MMA(III)-induced carcinogenesis.
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PMID:Monomethylarsonous acid produces irreversible events resulting in malignant transformation of a human bladder cell line following 12 weeks of low-level exposure. 2037 83

MicroRNAs (miRNAs) play critical roles in embryonic development and are frequently deregulated in human cancers. The let-7 family members are tumor-suppressing miRNAs and are frequently downregulated in cancer cells. Lin-28 and Lin-28B are RNA-binding proteins highly expressed in embryonic tissues. Lin-28 proteins block let-7 precursors from being processed to mature miRNAs by inducing terminal uridylation and degradation of let-7 precursors. Here, we report that Lin-28B, but not Lin-28, is highly expressed in hepatocellular carcinoma (HCC). Lin-28B expression was more frequently noted in high-grade HCCs with high alpha-fetoprotein levels. Knockdown of Lin-28B by RNA interference in the HCC cell line HCC36 suppressed proliferation in vitro and reduced in vivo tumor growth in NOD/SCID mice. In contrast, overexpression of Lin-28B in the HCC cell line HA22T enhanced tumorigenicity. Overexpression of Lin-28B also induced epithelial-mesenchymal transition in HA22T cells and hence, invasion capacity. Large-scale real-time PCR array analysis revealed that, among 380 miRNAs, only let-7/mir-98 family members were regulated by Lin-28B. Lin-28B overexpression enhanced the expression of the known let-7 targets c-myc and HMGA2. It was also found that Lin-28B enhanced the expression of type 1 insulin-like growth factor receptor in a let-7-dependent manner. These results indicate that Lin-28B regulates tumor formation and invasion in HCC through coordinated repression of the let-7/mir-98 family and induction of multiple oncogenic pathways.
Carcinogenesis 2010 Sep
PMID:Lin-28B expression promotes transformation and invasion in human hepatocellular carcinoma. 2052 79

Research into molecular and genetic mechanisms underlying prostate carcinogenesis in high-risk African American men would be greatly advanced by in vitro models of African American prostate tumors representing primary tumors. However, the generation of immortalized primary African American prostate cancer cells that will accurately reflect the in situ characteristics of malignant epithelium is currently limited but is greatly needed. We have successfully established immortalized cell lines of a pair of non-malignant and malignant tumors derived from an African American prostate cancer patient with HPV-16E6E7 (RC-77N/E and RC-77T/E). RC-77N/E and RC-77T/E cells are currently growing well at passage 40. Both cells exhibit epithelial morphology and are androgen sensitive. The RC-77T/E cells produced tumors in SCID mice whereas the RC-77N/E cells produced no tumor in SCID mice. These cells expressed androgen-regulated prostate-specific homobox gene, NKX 3.1, epithelial cell specific cytokeratn 8, androgen receptor (AR), prostate specific antigen (PSA), and p16. Chromosome analysis showed that both cell lines are similar; near diploid human male (XY) with most chromosome counts in the 45-48 range. However, RC-77T/E cell line has new marker chromosomes: M1B=del/t(4;?)(q28;?), M5=16q+ in addition to those observed in the RC-77N/E cell line (M1=del(4)(q28q34)+hsr in some, M1A=t(4q;?),M2=der(9?),M2A=del(M2p-),M3=iso(?), M4=der(22?)). This is the first documented case of the establishment of pair of non-malignant and malignant tumors derived from an African American prostate cancer patient. These models will provide novel tools to study the molecular and genetic mechanisms of prostate carcinogenesis, especially for high-risk African American men.
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PMID:Establishment and characterization of a pair of non-malignant and malignant tumor derived cell lines from an African American prostate cancer patient. 2104 16

Nicotinamide N-methyltransferase (NNMT) was recently identified as one clear cell renal cell carcinoma (ccRCC)-associated gene by analyzing full-length complementary DNA-enriched libraries of ccRCC tissues. The aim of this study is to investigate the potential role of NNMT in cellular invasion. A strong NNMT expression is accompanied with a high invasive activity in ccRCC cell lines, and small interfering RNA-mediated NNMT knockdown effectively suppressed the invasive capacity of ccRCC cells, whereas NNMT overexpression markedly enhanced that of human embryonic kidney 293 (HEK293) cells. A positive correlation between the expression of NNMT and matrix metallopeptidase (MMP)-2 was found in ccRCC cell lines and clinical tissues. The treatment of blocking antibody or inhibitor specific to MMP-2 significantly suppressed NNMT-dependent cellular invasion in HEK293 cells. Furthermore, SP-1-binding region of MMP-2 promoter was found to be essential in NNMT-induced MMP-2 expression. The specific inhibitors of PI3K/Akt signaling markedly decreased the binding of SP1 to MMP-2 promoter as shown by chromatin immunoprecipitation assay. We also demonstrated that PI3K/Akt pathway plays a role in NNMT-dependent cellular invasion and MMP-2 activation. Moreover, short hairpin RNA-mediated knockdown of NNMT expression efficiently inhibited the growth and metastasis of ccRCC cells in non-obese diabetic severe combined immunodeficiency mice. Taken together, the present study suggests that NNMT has a crucial role in cellular invasion via activating PI3K/Akt/SP1/MMP-2 pathway in ccRCC.
Carcinogenesis 2011 Feb
PMID:Nicotinamide N-methyltransferase induces cellular invasion through activating matrix metalloproteinase-2 expression in clear cell renal cell carcinoma cells. 2104 16

Rhabdomyosarcoma (RMS) is the most common soft-tissue sarcoma in children with an annual incidence of five new cases per million. Alveolar rhabdomyosarcoma (ARMS) is characterized by the t(2;13) or t(1;13) chromosomal translocations, which generate the PAX3-FOXO1 or PAX7-FOXO1 fusion genes, respectively. The oncogenic activity of PAX3-FOXO1 has been demonstrated in vitro and in vivo, yet expression of the fusion protein alone in primary myoblasts or a mouse model is insufficient for tumorigenic transformation. To identify genes cooperating with PAX3-FOXO1 in ARMS tumorigenesis, we generated a retroviral complementary DNA (cDNA) expression library from the Rh30 ARMS cell line. Arf-/- myoblasts expressing PAX3-FOXO1 and the retroviral cDNA library rapidly formed tumors after subcutaneous injection into NOD-SCID mice. Tumors formed by Arf-/-/PAX3-FOXO1/MarX-library myoblasts contained an unknown cDNA, encoding the C-terminus of the Homo sapiens hypothetical protein, FLJ10404, herein named IRIZIO. Expression of full length IRIZIO cDNA also cooperated with PAX3-FOXO1 in the transformation of Arf-/- myoblasts. Given that IRIZIO is expressed at increased levels in RMS, it might contribute to rhabdomyosarcomagenesis in humans.
Carcinogenesis 2011 Apr
PMID:IRIZIO: a novel gene cooperating with PAX3-FOXO1 in alveolar rhabdomyosarcoma (ARMS). 2117 67

A sarcomatoid carcinoma cell line (SAR-HCV) was established from a malignant liver lesion of a patient infected with hepatitis C virus. SAR-HCV cells were successfully xenografted in SCID mice. Vimentin was strongly positive in cultured SAR-HCV cells, the primary tumour lesion and the xenografts. Hepatocyte paraffin 1 protein and certain cytokeratin markers, CK8, CK18 and AE1/AE3 were not detected in cultured cells, but were focally positive in the tumour lesion and xenografts, suggesting that this cancer cell line preserves some features of hepatocyte differentiation when grown in vivo. HLA class I, N-cadherin, vascular endothelial growth factor, CD44, and heat-shock protein 70 were moderately expressed in this cell line. Spectral karyotyping analysis revealed a nearly triploid karyotype, 34-63<3n>, XXY[12] with complicated genetic abnormalities of chromosomal structure in all metaphases examined. This cell line will be useful in further studying hepato-sarcomatoid carcinoma cells and in understanding carcinogenesis and epithelial-mesenchymal transition in hepatitis C virus-related liver tumour.
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PMID:New sarcomatoid cancer cell line SAR-HCV established from a hepatitis C virus-related liver tumour lesion. 2127 90

Epigenetic fields for cancerization are involved in development of human cancers, especially those associated with inflammation and multiple occurrences. However, it is still unclear when such field defects are formed and what component of inflammation is involved in induction of aberrant DNA methylation. Here, in a mouse colitis model induced by dextran sulfate sodium (DSS), we identified three CpG islands specifically methylated in colonic epithelial cells exposed to colitis. Their methylation levels started to increase as early as 8 weeks after DSS treatment and continued to increase until colon cancers developed at 15 weeks. In contrast to the temporal profile of DNA methylation levels, infiltration of inflammatory cells spiked immediately after the DSS treatment and then gradually decreased. Exposure of cultured colonic epithelial cells to DSS did not induce DNA methylation and it was indicated that inflammation triggered by the DSS treatment was responsible for methylation induction. To clarify components of inflammation involved, severe combined immunodeficiency (SCID) mice that lack functional T- and B-cells were similarly treated. Even in SCID mice, DNA methylation, along with colon tumors, were induced at the same levels as in their background strain of mice (C.B17). Comparative analysis of inflammation-related genes showed that Ifng, Il1b and Nos2 had expression concordant with methylation induction whereas Il2, Il6, Il10, Tnf did not. These results showed that an epigenetic field defect is formed at early stages of colitis-associated carcinogenesis and that functional T and B cells are non-essential for the formation.
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PMID:Early-stage formation of an epigenetic field defect in a mouse colitis model, and non-essential roles of T- and B-cells in DNA methylation induction. 2168 42

Members of the extracellular signal-regulated kinase (ERK) family may have distinct roles in the development of cell injury and repair, differentiation and carcinogenesis. Here, we show, using a synthetic small-molecule MEK1/2 inhibitor (U0126) and RNA silencing of ERK1 and 2, comparatively, that ERK2 is critical to transformation and homeostasis of human epithelioid malignant mesotheliomas (MMs), asbestos-induced tumors with a poor prognosis. Although MM cell (HMESO) lines stably transfected with shERK1 or shERK2 both exhibited significant decreases in cell proliferation in vitro, injection of shERK2 cells, and not shERK1 cells, into immunocompromised severe combined immunodeficiency (SCID) mice showed significant attenuated tumor growth in comparison to shControl (shCon) cells. Inhibition of migration, invasion and colony formation occurred in shERK2 MM cells in vitro, suggesting multiple roles of ERK2 in neoplasia. Microarray and quantitative real-time PCR analyses revealed gene expression that was significantly increased (CASP1, TRAF1 and FAS) or decreased (SEMA3E, RPS6KA2, EGF and BCL2L1) in shERK2-transfected MM cells in contrast to shCon-transfected MM cells. Most striking decreases were observed in mRNA levels of Semaphorin 3 (SEMA3E), a candidate tumor suppressor gene linked to inhibition of angiogenesis. These studies demonstrate a key role of ERK2 in novel gene expression critical to the development of epithelioid MMs. After injection of sarcomatoid human MM (PPMMill) cells into SCID mice, both shERK1 and shERK2 lines showed significant decreased tumor growth, suggesting heterogeneous effects of ERKs in individual MMs.
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PMID:ERK2 is essential for the growth of human epithelioid malignant mesotheliomas. 2171 Apr 92

Drug resistance remains a clinical challenge in cancer treatment due to poor understanding of underlying mechanisms. We have established several drug-resistant prostate cancer cell lines by long-term culture in medium containing chemotherapeutic drugs. These resistant lines displayed a significant increase in side population cells due to overexpression of drug efflux pumps including ABCG2/BCRP and MDR1/Pgp. To uncover potential mechanisms underlying drug resistance, we performed microarray analysis to identify differentially expressed genes in 2 drug-resistant lines. We observed that POU5F1/OCT4, a transcription factor key to regulating pluripotency in embryonic stem cells, was upregulated in drug-resistant lines and accompanied by transcriptional activation of a set of its known target genes. Upregulation of OCT4 in drug-resistant cells was validated by RT-PCR and sequencing of PCR products as well as confirmation by Western blot and specific shRNA knockdown. Analysis of the regulatory region of POU5F1/OCT4 revealed a reduction of methylation in drug-resistant cell lines. Furthermore, these drug-resistant cells exhibited a significant increase in tumorigenicity in vivo. Subcutaneous inoculation of as few as 10 drug-resistant cells could initiate tumor formation in SCID mice, whereas no detectable tumors were observed from the parental line under similar conditions, suggesting that these drug-resistant cells may be enriched for tumor-initiating cells. Knocking down OCT4 expression by specific shRNAs attenuated growth of drug-resistant cells. Our data suggest that OCT4 re-expression in cancer cells may play an important role in carcinogenesis and provide one possible mechanism by which cancer cells acquire/maintain a drug-resistant phenotype.
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PMID:A Role for OCT4 in Tumor Initiation of Drug-Resistant Prostate Cancer Cells. 2177 71


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