Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0009402 (colorectal cancer)
 53,228 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The biological effects of retinoic acid (RA) are mediated by nuclear retinoic acid receptors (RARs) that function as ligand-activated transcriptional factors. The response of human cancer cells to RA is known to be associated with the expression of RARbeta. Recent studies have demonstrated that the loss of RARbeta expression is involved in the development of a variety of human malignancies. We show that recombinant adenovirus-mediated p21(sdi1) gene transfer enhances RARbeta mRNA expression as well as protein expression and induces the sensitivity to all-trans RA (ATRA) in human cancer cells. Semi-quantitative reverse transcription-polymerase chain reaction analysis demonstrated that infection with adenovirus carrying human p21(sdi1) gene (Ad5CMV-p21), which encodes a cyclin-dependent kinase inhibitor, induced RARbeta mRNA and protein expression in H1299 human non-small cell lung cancer cells and DLD-1 human colorectal cancer cells. We also found that exogenous introduction of the p21(sdi1) gene transcriptionally activated the upstream promoter function of the RARbeta gene. Treatment with 1 microM of ATRA showed no significant inhibitory effects on the growth of H1299 and DLD-1 cells; after Ad5CMV-p21 infection, however, cells underwent apoptosis with ATRA treatment at the same concentration, suggesting that p21(sdi1) gene transfer sensitized H1299 and DLD-1 cells, presumably, through RARbeta upregulation. We also demonstrated the efficacy of intratumoral injection of Ad5CMV-p21 in combination with systemic administration of ATRA in a nude mice xenograft model. Our results indicate that recombinant adenovirus-mediated p21(sdi1) gene transfer could be potentially useful for the local induction of RA sensitivity in human premalignant and malignant lesions lacking appropriate RARbeta expression.
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PMID:Ectopic p21sdi1 gene transfer induces retinoic acid receptor beta expression and sensitizes human cancer cells to retinoid treatment. 1251 7

5-Fluorouracil (5-FU) is the major chemotherapeutic component for colorectal cancer (CRC) and other types of solid tumours. Resistance of cancer cells to 5-FU is considered the major obstacle for successful chemotherapy. NF-kappaB is a transcription factor. Cancer cells with high NF-kappaB nuclear activity demonstrate robust chemo- and radio-resistance. We demonstrated that nuclear NF-kappaB activity in CRC cell lines, DLD-1 and RKO(WT), was significantly induced by 5-FU in a concentration- and time-dependent manner. 5-FU induced IkappaBalpha degradation and promoted both NF-kappaB nuclear translocation and its DNA binding activity. 5-FU treatment did not influence the activities of AP-1, AP-2, Oct-1, SP-1, CRE-B and TFIID. Disulfiram (DS), a clinically used anti-alcoholism drug, strongly inhibited constitutive and 5-FU-induced NF-kappaB activity in a dose-dependent manner. DS inhibited both NF-kappaB nuclear translocation and DNA binding activity but had no effect on 5-FU-induced IkappaBalpha degradation. Used in combination, DS significantly enhanced the apoptotic effect of 5-FU on DLD-1 and RKO(WT) cell lines and synergistically potentiated the cytotoxicity of 5-FU to both cell lines. DS also effectively abolished 5-FU chemoresistance in a 5-FU resistant cell line H630(5-FU) in vitro. As DS has extensive preclinical and clinical experience, translating its anticancer usage from in vitro study to clinical trials is relatively straightforward.
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PMID:Disulfiram-mediated inhibition of NF-kappaB activity enhances cytotoxicity of 5-fluorouracil in human colorectal cancer cell lines. 1258 50

HIF-1 is reported to transactivate expression of VEGF, which is an important angiogenic factor. To determine whether HIF-1alpha plays a role in angiogenesis through its regulation of VEGF, we examined expression of HIF-1alpha and its relation to clinicopathologic features, VEGF expression and prognosis of patients with colorectal carcinoma. Expression of HIF-1alpha and VEGF was examined in 4 colorectal carcinoma cell lines (COLO320DM, COLO201, DLD-1, WiDr) and 149 colorectal carcinoma tissues (10 fresh specimens, 139 archival, paraffin-embedded specimens). HIF-1alpha protein levels were increased by hypoxia in 3 of 4 colorectal carcinoma cell lines (COLO201, DLD-1, WiDr), and VEGF mRNA levels were also increased by hypoxia in the same cell lines. In 8 of 10 patients with colorectal cancer, expression of HIF-1alpha and VEGF was increased in tumor tissues compared to corresponding normal mucosa. Of 139 archival specimens of colorectal carcinoma, 81 (58.3%) expressed HIF-1alpha protein at a high level. HIF-1alpha expression was correlated with tumor invasion, tumor stage, lymphatic invasion, venous invasion and liver metastasis. Moreover, HIF-1alpha expression was correlated significantly with VEGF expression and microvessel density. Although there was a tendency for poorer prognosis in patients with high HIF-1alpha-expressing tumors, this correlation was not statistically significant. These findings suggest that HIF-1alpha may play a role in angiogenesis and tumor progression via regulation of VEGF in human colorectal carcinoma.
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PMID:Expression of hypoxia-inducible factor-1alpha is associated with tumor vascularization in human colorectal carcinoma. 1267 75

The chromosomal aberrations underlying the development of resistance to fluoropyrimidines have not yet been identified. To characterise the genomic changes that induce the development of resistance to fluoropyrimidines, we used comparative genomic hybridisation (CGH) to analyse and compare the parent DLD-1 human colorectal cancer cell line and two cell lines, DLD-1/5-FU and DLD-1/FdUrd, which were resistant to 5-fluorouracil (5-FU) and 5-fluoro-2'-deoxyuridine (FdUrd), respectively. Both resistant cell lines showed a genetic aberration derived from the parental cell line DLD-1. Losses of 3p and 3q were also detected as additional genetic changes in the two resistant cell lines. Both resistant cell lines showed decreased orotate phosphoribosyltransferase (OPRT) activity, which is associated with the activity of the uridine monophosphate (UMP) synthase gene (3q13). These results suggested that the loss of 3q might be a genetic change responsible for the decreased OPRT activity and fluoropyrimidine cytotoxic response in cancer cells. Amplification of 18p11.2-p11.3 containing the thymidine synthase (TS) gene (18p11.32) was observed only in the DLD-1/FdUrd-resistant cell line, which overexpresses TS. These findings suggested that 18p amplification represents a genetic change associated with the overexpression of the TS protein. Our results indicate that chromosomal aberrations identified by CGH could explain, at least in part, acquired fluoropyrimidine resistance.
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PMID:Chromosomal imbalances associated with acquired resistance to fluoropyrimidines in human colorectal cancer cells. 1270 67

The tumor-suppressor gene PTEN encodes a multifunctional phosphatase that is mutated in a variety of human cancers. PTEN inhibits the phosphatidylinositol 3-kinase pathway and downstream functions, including activation of Akt/protein kinase B (PKB), cell survival, and cell proliferation in tumor cells carrying mutant- or deletion-type PTEN. In such tumor cells, enforced expression of PTEN decreases cell proliferation through cell-cycle arrest at G1 phase accompanied, in some cases, by induction of apoptosis. More recently, the tumor-suppressive effect of PTEN has been reported in ovarian and thyroid tumors that are wild type for PTEN. In the present study, we examined the tumor-suppressive effect of PTEN in human colorectal cancer cells that are wild type for PTEN. Adenoviral-mediated transfer of PTEN (Ad-PTEN) suppressed cell growth and induced apoptosis significantly in colorectal cancer cells (DLD-1, HT29, and SW480) carrying wtPTEN than in normal colon fibroblast cells (CCD-18Co) carrying wtPTEN. This suppression was induced through downregulation of the Akt/PKB pathway, dephosphorylation of focal adhesion kinase (FAK) and mitogen-activated protein kinase (MAPK) and cell-cycle arrest at the G2/M phase, but not the G1 phase. Furthermore, treatment of human colorectal tumor xenografts (HT-29, and SW480) with Ad-PTEN resulted in significant (P=0.01) suppression of tumor growth. These results indicate that Ad-PTEN exerts its tumor-suppressive effect on colorectal cancer cells through inhibition of cell-cycle progression and induction of cell death. Thus Ad-PTEN may be a potential therapeutic for treatment of colorectal cancers.
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PMID:Adenovirus-mediated transfer of the PTEN gene inhibits human colorectal cancer growth in vitro and in vivo. 1452 20

A novel member of the human AMPK family, ARK5, was recently discovered to be a key molecule in mediating cancer cell migration activity in human pancreas cancer cell line PANC-1, and its activation was found to be induced by Akt-dependent phosphorylation at Ser 600. DNA array analysis with 241 paired cDNAs from 13 different types of tumors and corresponding normal tissues derived from cancer patients revealed ARK5 overexpression in the samples of colorectal cancer. ARK5 expression was measured and an in vitro invasion assay was performed in six human colorectal cancer cell lines, WiDr, HCT-15, DLD-1, SW620, LoVo, and SW480, and since high invasion activity was concordant with higher ARK5 expression, ARK5 expression was examined in relation to tumor progression and metastatic activity in clinical samples. In 56 clinical samples of primary colorectal cancers and their liver metastases, higher ARK5 expression was observed in the samples from more advanced cases, and much higher expression was observed in the liver metastases. In situ hybridization analysis showed ARK5 overexpression in tumor cells. Based on these findings, we propose that ARK5 overexpression is involved in tumor progression of colon cancer clinically.
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PMID:ARK5 expression in colorectal cancer and its implications for tumor progression. 1498 52

The novel, proinflammatory cytokine endothelial monocyte-activating polypeptide-II (EMAP-II) was first found in tumor cell supernatants. EMAP-II is closely related or identical to the p43 auxiliary protein of the multisynthase complex, which is involved in protein synthesis. In vitro, EMAP-II induces procoagulant activity, increased expression of E- and P-selectins and tumor necrosis factor receptor-1, and ultimately, programmed cell death (apoptosis) in cultured endothelial cells. EMAP-II is also chemotactic for monocytes and neutrophils. However, the role of the p43/EMAP-II cytokine form in tumors is not understood. We hypothesized an immune-regulatory role within neoplastic tissues and investigated its effects on lymphocytes. EMAP-II causes a dose-dependent inhibition of proliferation and apoptosis in Jurkat T cells and mitogen-activated peripheral blood mononuclear cells. Coculture with DLD-1 colorectal cancer cells or media conditioned by these cells induces apoptosis in Jurkat cells, which is partially reversed by antibodies against EMAP-II. Our data suggest that EMAP-II constitutes a component of a novel, immunosuppressive pathway in solid tumors, which is not normally expressed outside the cell but in tumors, may be subject to abnormal processing and released from tumor cells.
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PMID:Endothelial monocyte-activating polypeptide-II (EMAP-II): a novel inducer of lymphocyte apoptosis. 1498 44

Recently, evidence has accumulated that weekly 24-h infusion of high-dose 5-fluorouracil (5-FU) with leucovorin (LV, folinic acid) biochemical modulation may improve the response rates compared with the bolus 5-FU regimens in colorectal cancer (CRC). Combining the infusional 5-FU/LV (iFL) regimens with oxaliplatin or irinotecan is widely adopted to further improve treatment efficacy. Either oxaliplatin-iFL or irinotecan-iFL may achieve an overall response rate of more than 50% in the first-line treatment. Intriguingly, in the salvage treatment for metastatic CRC patients who had failed iFL, only oxaliplatin-iFL may achieve a response rate of about 13-25%. In contrast, oxaliplatin alone or irinotecan-iFL had a very low response rate of 5% or less. To test if the oxaliplatin may reverse the iFL-related 5-FU resistance in CRC, we used DLD-1 colon adenocarcinoma cells as the in vitro study model. First, we revealed that oxaliplatin and 5-FU act synergistically on DLD-1 cells by MTT cytotoxicity assay and median drug effect analysis. Second, we treated the DLD-1 cells with serial concentrations of oxaliplatin (0.1-10 microM). Oxaliplatin treatment results in down-regulation of free thymidylate synthase (TS) protein expression by Western blotting. Further, we analyzed the TS mRNA level by reverse transcription and real-time quantitative polymerase chain reaction assay. Oxaliplatin treatment results in down-regulation of the TS mRNA level up to 40% (mean +/- SD of ratio to reference control = 0.60 +/- 0.21, range 0.42-0.84). In this study, our data provide important information explaining the reason why the combination of oxaliplatin and 5-FU results in a better objective response in 5-FU-resistant patients than oxaliplatin alone does. Our data also suggest that TS down-regulation happens at the transcriptional level. TS modulation and down-regulation had, thus, shed light on the useful potential strategy to achieve objective responses in 5-FU-resistant CRC patients.
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PMID:Down-regulation of thymidylate synthase expression and its steady-state mRNA by oxaliplatin in colon cancer cells. 1505 42

A large proportion of epithelial cancers show the chromosome-instability phenotype, in which they have many chromosome abnormalities. This is thought to be the result of mutations that disrupt chromosome maintenance, but the causative mutations are not known. We identified cell lines known to have mutations that might cause chromosome instability, and examined their karyotypes. Two cell lines, the breast cancer line HCC1937 and the pancreatic cancer line CAPAN-1, that have mutations respectively in BRCA1 and BRCA2, had very abnormal karyotypes, with many structural and numerical chromosome changes and substantial variation between metaphases. However, two colorectal cancer lines with mutations in BUB1, a spindle checkpoint protein involved in chromosome segregation, had rather simple near-tetraploid karyotypes, with minimal loss or gain of chromosomes other than the endoreduplication event, and minimal structural change. Apart from tetraploidy, these karyotypes were typical of colorectal lines considered to be chromosomally stable. Two lines derived from the same tumour, DLD-1 and HCT-15, with bi-allelic mutation of CHK2, had karyotypes that were typical of near-diploid colorectal lines considered chromosomally stable. The karyotypes observed supported the proposed role for BRCA1 and BRCA2 mutations in chromosomal instability, but showed that the tested mutations in BUB1 and CHK2 did not result in karyotypes that would have been predicted if they were sufficient for chromosomal instability.
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PMID:Possible causes of chromosome instability: comparison of chromosomal abnormalities in cancer cell lines with mutations in BRCA1, BRCA2, CHK2 and BUB1. 1516 61

Colorectal cancer cells are unique in that they escape Fas-mediated cell death in the presence of Fas ligand, and we recently reported that AMP-activated protein kinase-related kinase 5 (ARK5) suppresses cell death signaling mediated by cell death receptor in Akt-dependent manner. In the current study, therefore, we examined whether ARK5 is involved in the escape from Fas-mediated cell death of colorectal cancer cells. Among 10 cell lines, ARK5 mRNA expression was observed in LoVo, SW480, and SW1116 cell lines. Interestingly, SW480 and SW1116 cell lines, but not LoVo cell line, showed expressions of both Fas ligand (FasL) and Fas mRNAs. SW620 cell line also showed FasL mRNA; however, Fas and ARK5 mRNAs were not detected. Furthermore, well-coincided expression among ARK5, FasL, and Fas mRNAs was observed in tumor tissues from patients with colorectal cancer, suggesting the suppression of FasL/Fas system-induced cell death by ARK5 in colorectal cancer cell lines. Intensive cell death, which was dependent on the FasL/Fas system was encountered when ARK5 antisense RNA (ARK5/AS) was introduced into SW480 cells. FLIP was expressed in only ARK5 mRNA-expressing cell lines, and ARK5/AS induced FLIP cleavage in a caspase-6-dependent manner. Amino-acid sequence analysis of caspase-6 revealed two putative sites of phosphorylation by ARK5 at Ser80 and Ser257. Although active caspase-6 overexpression induced cell death in SW480 and DLD-1 cell lines, SW480 cells, but not DLD-1 cells, exhibited strong resistance to procaspase-6 overexpression. Moreover, mutant caspase-6, in which the Ser257 was substituted by Ala (caspase-6/SA), induced cell death and FLIP degradation, even in SW480 cells. Active ARK5 was found to phosphorylate wild-type caspase-6 in vitro, but not caspase-6/SA, and the prevented activation of caspase-6 was promoted due to its phosphorylation by active ARK5 in vitro. On the basis of the results of this study, we propose that ARK5 negatively regulates procaspase-6 by phosphorylation at Ser257, leading to resistance to the FasL/Fas system.
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PMID:Regulation of caspase-6 and FLIP by the AMPK family member ARK5. 1527 17


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