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

The chromosome region 8p12-p22 shows frequent allelic loss in many neoplasms, including breast cancer (BC). The DLC-1 gene, located on 8p21-p22, might be a candidate tumor suppressor gene in this region. To evaluate the involvement of DLC-1 in breast carcinogenesis we studied DLC-1 mRNA expression in a panel of 14 primary human BC and the corresponding normal breast cells as well as 8 BC cell lines. Low levels or absence of DLC-1 mRNA were observed in 57% of primary BC and 62.5% of BC cell lines, respectively. We could not find any correlation between DLC-1 mRNA expression and deletions at the DLC-1 locus. Transfection of the gene into DLC-1 deficient T-47D cells raised the DLC-1 mRNA level and resulted in inhibition of cell growth and reduced colony-forming capacity. Our results indicate a role of DLC-1 in BC carcinogenesis.
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PMID:Analysis of DLC-1 expression in human breast cancer. 1275 48

DLC-1 (deleted in liver cancer) gene is frequently deleted in hepatocellular carcinoma. However, little is known about the genetic status and the expression of this gene in gastric cancer. In this study, Northern and Southern analysis showed that seven of nine human gastric cancer cell lines did not express DLC-1 mRNA, but contained the DLC-1 gene. To identify the mechanism of the loss of DLC-1 mRNA expression in these cell lines, we investigated the methylation status of DLC-1 gene by using methylation-specific PCR (MSP) and Southern blot, and found that five of seven DLC-1 nonexpressing gastric cancer cell lines were methylated in the DLC-1 CpG island. Treatment with 5-aza-2'-deoxycytidine (5-Aza-dC) induced DLC-1 mRNA expression in the gastric cancer cell lines that have the methylated alleles. Studies using SNU-601 cell line with methylated DLC-1 alleles revealed that nearly all CpG sites within DLC-1 CpG island were methylated, and that the in vitro methylation of the DLC-1 promoter region is enough to repress DLC-1 mRNA expression, regardless of the presence of transcription factors capable of inducing this gene. In all, 29 of 97 (30%) primary gastric cancers were also shown to be methylated, demonstrating that methylation of the DLC-1 CpG island is not uncommon in gastric cancer. In addition, we demonstrated that DLC-1 mRNA expression was induced, and an increase in the level of acetylated H3 and H4 was detected by the treatment with trichostatin A (TSA) in two DLC-1 nonexpressing cell lines that have the unmethylated alleles. Taken together, the results of our study suggest that the transcriptional silencing of DLC-1, by epigenetic mechanism, may be involved in gastric carcinogenesis.
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PMID:Transcriptional silencing of the DLC-1 tumor suppressor gene by epigenetic mechanism in gastric cancer cells. 1281 68

Non-Hodgkin's lymphoma (NHL) is a group of malignancies with heterogeneous genetic and epigenetic alterations. Discovery of molecular markers that better define NHL should improve diagnosis, prognosis and understanding of the biology. We developed a CpG island DNA microarray for discovery of aberrant methylation targets in cancer, and now apply this method to examine NHL cell lines and primary tumors. This methylation profiling revealed differential patterns in six cell lines originating from different subtypes of NHL. We identified 30 hypermethylated genes in these cell lines and independently confirmed 10 of them. Methylation of 6 of these genes was then further examined in 75 primary NHL specimens composed of four subtypes representing different stages of maturation. Each gene (DLC-1, PCDHGB7, CYP27B1, EFNA5, CCND1 and RARbeta2) was frequently hypermethylated in these NHLs (87, 78, 61, 53, 40 and 38%, respectively), but not in benign follicular hyperplasia. Although some genes such as DLC-1 and PCDHGB7 were methylated in the vast majority of NHLs, others were differentially methylated in specific subtypes. The methylation of the candidate tumor suppressor gene DLC-1 was detected in a high proportion of primary tumor and plasma DNA samples by using quantitative methylation-specific PCR analysis. This promoter hypermethylation inversely correlated with DLC-1 gene expression in primary NHL samples. Thus, this CpG island microarray is a powerful discovery tool to identify novel methylated genes for further studies of their relevant molecular pathways in NHLs and identification of potential epigenetic biomarkers of disease.
Carcinogenesis 2007 Jan
PMID:Discovery of novel epigenetic markers in non-Hodgkin's lymphoma. 1677 33

DLC-1 (deleted in liver cancer-1) is a potential tumor suppressor gene, which is inactive in liver carcinogenesis. To observe the effects of DLC-1 gene expression on cell proliferation and migration in the human colon cancer cell line, RNAi Lipo-recombinant of the DLC-1 gene (pGCsil-DLC-1) was constructed and transduced into LoVo cells which are positive for DLC-1 gene expression. Results showed that the RNAi recombinant effectively inhibited the expression of the DLC-1 gene in LoVo cells. Additionally, our data showed decreased DLC-1 gene expression which resulted in the promotion of LoVo cell proliferation. Flow cytometry in cell cycle detection further indicated that the DLC-1 gene induced cell cycle arrest at G2/M and a cell migration assay confirmed that the knocking down of DLC-1 gene expression promotes LoVo cell migration. Our observations suggest that the DLC-1 gene is associated with LoVo cell proliferation, migration and cell cycle distribution. DLC-1 is a potential suppressor gene in the colon cancer LoVo cell line and may play an important role in colon cancer mechanisms.
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PMID:Inhibition of DLC-1 gene expression by RNA interference in the colon cancer LoVo cell line. 1828

Rho GTPases are major regulators of signal transduction pathways and play key roles in processes including actin dynamics, cell cycle progression, cell survival and gene expression, whose deregulation may lead to tumorigenesis. A growing number of in vitro and in vivo studies using tumor-derived cell lines, primary tumors and animal cancer models strongly suggest that altered Rho GTPase signaling plays an important role in the initiation as well as in the progression of hepatocellular carcinoma (HCC), one of the deadliest human cancers in the world. These alterations can occur at the level of the GTPases themselves or of one of their regulators or effectors. The participation into the tumorigenic process can occur either through the over-expression of one of these components which presents an oncogenic activity as illustrated with RhoA and C or through the attenuation of the expression of a component presenting tumor suppressor activity as for Cdc42 or the RhoGAP, DLC-1. Consequently, these observations reflect the heterogeneity and the complexity of liver carcinogenesis. Recently, pharmacological approaches targeting Rho GTPase signaling have been used in HCC-derived models with relative success but remain to be validated in more physiologically relevant systems. Therefore, therapeutic approaches targeting Rho GTPase signaling may provide a novel alternative for anti-HCC therapy.
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PMID:Rho GTPases in hepatocellular carcinoma. 1916 29

The lack of effective anti-tumor therapy for renal cell carcinoma (RCC) has stimulated the search for novel target whose inhibition could block tumorigenesis. Recently, reduced DLC-1 has been shown to be associated with aggressive and highly metastatic renal cell carcinoma. In this study, the biological role of DLC-1 on cell growth, migration and cell cycle progression in RCC cells was investigated. Over-expression of DLC-1 was associated with a marked inhibition of cell growth (P<0.01). The inhibitory effect was partly due to the induction of apoptosis and cell cycle arrest in G(0)/G(1) accompanied by up-regulation of the intracellular signal proteins of p27 and down-regulation of cyclin D1 and cyclin E. Furthermore, DLC-1 induced FAK dephosphorylation of focal adhesion proteins inhibited cell migration (P<0.05). Decreased DLC-1 expression strongly correlated with proliferative activity, as indicated by the elevated levels of Ki67. Restoration of DLC-1 expression in RCC cells led to Bcl-2 and caspase-3 mediated apoptosis as well as attenuated the ability of the cells to form RCC tumors in athymic nude mice (P<0.05). Taken together, these results suggest that DLC-1 plays a crucial role in signal transduction pathway regulating the cell proliferation, migration, and carcinogenesis of human RCC.
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PMID:Overexpression of DLC-1 induces cell apoptosis and proliferation inhibition in the renal cell carcinoma. 1938 Jan 90

Pancreatic ductal adenocarcinoma (PDA) is one of the most aggressive malignancies in humans, and its prognosis is generally poor even after surgery. Many advances have been made to understand the pathogenesis of PDA; however, the molecular mechanisms that lead to pancreatic carcinogenesis are still not clearly understood. The aims of this study were to investigate the relationship between DLC-1 methylation status and clinicopathological characteristics of PDA patients and evaluate the role of DLC-1 methylation status in PDA. The expression of DLC-1 mRNA in PDA tissues was analyzed by real-time PCR. The methylation status of DLC-1 was analyzed by methylation-specific polymerase chain reaction (MSP). Furthermore, we determined the prognostic importance of DLC-1 methylation status in PDA patients. Our results showed that the expression level of DLC-1 mRNA in PDA tissues was lower than that in non-cancerous tissues. The rate of DLC-1 promoter methylation was significantly higher in PDA tissues than in adjacent non-cancerous tissues (p < 0.001). Downregulation of DLC-1 was strongly correlated with promoter methylation (P = 0.003). The presence of DLC-1 methylation in PDA tissue samples was significantly correlated with clinical stage (P = 0.005), histological differentiation (P = 0.05), and lymph node metastasis (P = 0.006). Kaplan-Meier survival analysis showed that DLC-1 methylation status was inversely correlated with overall survival of the PDA patients. Further, Cox multivariate analysis indicated that DLC-1 methylation status was an independent prognostic factor for the overall survival rate of PDA patients. In conclusion, our data suggest that downregulation of DLC-1 may be explained by DNA methylation; DLC-1 may be a biomarker for PDA.
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PMID:DLC-1 is a candidate biomarker methylated and down-regulated in pancreatic ductal adenocarcinoma. 2368 4

Previous studies have shown that promoter hypermethylation plays a key role in DLC-1 inactivation in nasopharyngeal carcinoma (NPC). However, DLC-1 mutation in NPC has not been reported, and there remain some discrepancies in methods and results between different groups. Here, we examined the mRNA and protein expression of DLC-1 in chronic nasopharyngitis (CN) and NPC tissues by reverse transcription-polymerase chain reaction/qPCR and immunohistochemistry, respectively. DLC-1 mRNA was undetectable in all the seven widely used NPC cell lines and absent or significantly down-regulated in 70% of NPC tissues. DLC-1 protein level was reduced in 74.3% of NPCs when compared with CN tissues, and significantly lower in NPC samples at advanced clinical stages than that at early stages. Then, we purified the same batch of specimens by microdissection and analyzed the possible mechanisms of DLC-1 downregulation with mutation and allelic loss analysis, methylation-specific PCR and bisulfite genomic sequencing. Only one mutation was detected at codon 693 of exon 8 in 3.3% of NPCs and five single nucleotide polymorphisms (SNPs) were identified. Loss of DLC-1 was detected in 23.3% of NPC tissues. The 100% of NPC cell lines, 80% of primary NPC and 22.2% of CN tissues showed methylation in DLC-1 promoter, while DLC-1 expression was recovered in seven NPC cell lines after 5-aza-dC treatment. Patched methylation assay confirmed that promoter methylation could repress DLC-1 expression. This report demonstrates that DLC-1 is negatively associated with NPC carcinogenesis, and promoter hypermethylation along with loss of heterozygosity, but not mutation, contributes to inactivation of DLC-1 in NPC.
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PMID:Promoter hypermethylation along with LOH, but not mutation, contributes to inactivation of DLC-1 in nasopharyngeal carcinoma. 2390 59

Emerging evidence indicates that IGF2 plays an important role in various human malignancies, including colorectal cancer (CRC). Hsa-miR-483 is located within intron 7 of the IGF2 locus. However, the mechanism by which increased IGF2 induces carcinogenesis remains largely elusive. DLC-1 has been identified as a candidate tumor suppressor. In this study, we aimed at investigating whether miR-483 transcription is IGF2-dependent, identifying the functional target of miR-483, and evaluating whether tissue and serum miR-483-3p or miR-483-5p levels are associated with CRC. Our results showed that sequences upstream miR-483 had undetectable promoter activity and levels of IGF2, miR-483-3p, and miR-483-5p were synchronously increased in CRC tissues. Positive correlations between IGF2 and miR-483-3p (r=0.4984, ***p<0.0001), and between IGF2 and miR-483-5p (r=0.6659, ***p<0.0001) expression were found. In addition, patients with CRC had a significantly higher serum miR-483-5p level (*p<0.05) compared to normal controls. DLC-1 expression was decreased in colorectal cancer tissues and diminished through transient transfection with miR-483-3p. Our results suggest that IGF2 may exert its oncofunction, at least partly, through its parasitic miR-483 which suppressed DLC-1 in CRC cells. Thus, miR-483 might serve as a new target for therapy and a potential biomarker for the detection of colorectal cancer.
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PMID:IGF2-derived miR-483 mediated oncofunction by suppressing DLC-1 and associated with colorectal cancer. 2736 46