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Query: UMLS:C0009402 (colorectal cancer)
 53,228 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study, we estimated the expression of c-MET/Hepatocyte Growth Factor receptor in colorectal cancers by immunohistochemistry. In 118 patients, c-MET wee expressed in 65 patients (55%). About the clinicopathological findings of metastasis, the proportion of c-MET-positive in the patients with liver metastasis, 78% (18/23), was significantly higher than that without liver metastasis, 49% (47/95), but there was no significant difference about lymph node metastasis and peritoneal dissemination. About the pathological findings of primary lesion, the proportion of c-MET-positive in the patients with infiltration into lymphatic vessels, 63% (48/76), was significantly higher than that without infiltration, 40% (17/42), but there was no significant difference about infiltration into veins. The proportion of c-MET-positive increased as the tumor stage proceeded from t1 to t4 and as the histopathological stage proceeded from I to IV. These results suggest that c-MET may play an important role in the growth and scattering of colorectal cancer cells.
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PMID:[The expression of cMET/hepatocyte growth factor receptor in colorectal cancer]. 972 15

It has been shown that in hereditary and most sporadic colon tumours, components of the Wnt pathway are mutated. The Wnt target MET has been implicated in the development of colon cancer. Here, we show that overexpression of wild-type or a constitutively activated form of MET in colon epithelial cells leads to increased transformation irrespective of Wnt signalling. Fetal human colon epithelial cells without aberrant Wnt signalling were transfected with wild-type or mutated MET constructs. Expression of these constructs leads to increased phosphorylation of MET and its downstream targets PKB and MAPK. Upon stimulation with HGF, the expression of E-cadherin is downregulated in wild-type MET-transfected cells, whereas cells expressing mutated MET show low E-cadherin levels independent of stimulation with ligand. This implies a higher migratory propensity of these cells. Furthermore, fetal human colon epithelial cells expressing the mutated form of MET have colony-forming capacity in soft agar, while cells expressing wild-type MET show an intermediate phenotype. Subcutaneous injection of mutated MET-transfected cells in nude mice leads to the formation of tumours within 12 days in all mice injected. At this time point, mock-transfected cells do not form tumours, while wild-type MET-transfected cells form subcutaneous tumours in one out of five mice. We thus show that MET signalling can lead to increased transformation of colon epithelial cells independent of Wnt signalling and in this way could play an essential role in the onset and progression of colorectal cancer.
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PMID:MET signalling in primary colon epithelial cells leads to increased transformation irrespective of aberrant Wnt signalling. 1578 35

The receptor tyrosine kinase MET is overexpressed in human colorectal adenomas and carcinomas, suggesting an instrumental role for MET signaling in the onset and progression of colorectal cancer. To corroborate this role, animal models are needed. To study the expression of Met in the normal and neoplastic mouse intestine, we generated an Armenian hamster monoclonal antibody against mouse Met. By using this antibody in immunohistochemical studies, we observed strong Met expression in fetal mouse intestinal epithelial cells. In contrast, in the intestines of adult mice, Met expression was very low whereas the protein was undetectable on the neoplastic epithelium of intestinal adenomas in Apc+/min mice. By immunoblotting, we were also unable to detect Met in intestinal adenomas, whereas Met mRNA levels in microdissected adenomas were very low. The absence of detectable Met protein expression in adenomas of Apc+/min mice contrasts sharply with the vast overexpression of the protein in adenomas of humans with familial adenomatous polyposis or sporadic colorectal carcinomas. Our results imply that deregulation of Wnt signaling in mouse--unlike in human--intestinal epithelium does not result in Met overexpression. Our findings thus reveal important interspecies differences in the regulation of Met expression during intestinal tumorigenesis.
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PMID:Activation of Wnt signaling in the intestinal mucosa of Apc +/min mice does not cause overexpression of the receptor tyrosine kinase Met. 1686 4

Progression of colorectal cancer (CRC) involves spatial and temporal occurrences of epithelial-mesenchymal transition (EMT), whereby tumour cells acquire a more invasive and metastatic phenotype. Subsequently, the disseminated mesenchymal tumour cells must undergo a reverse transition (mesenchymal-epithelial transition, MET) at the site of metastases, as most metastases recapitulate the pathology of their corresponding primary tumours. Importantly, initiation of tumour growth at the secondary site is the rate-limiting step in metastasis. However, investigation of this dynamic reversible EMT and MET that underpins CRC morphogenesis has been hindered by a lack of suitable in vitro models. To this end, we have established a unique in vitro model of CRC morphogenesis, which we term LIM1863-Mph (morphogenetic). LIM1863-Mph cells spontaneously undergo cyclic transitions between two-dimensional monolayer (migratory, mesenchymal) and three-dimensional sphere (carcinoid, epithelial) states. Using RNAi, we demonstrate that FZD7 is necessary for MET of the monolayer cells as loss of FZD7 results in the persistence of a mesenchymal state (increased SNAI2/decreased E-cadherin). Moreover, FZD7 is also required for migration of the LIM1863-Mph monolayer cells. During development, FZD7 orchestrates either migratory or epithelialization events depending on the context. Our findings strongly implicate similar functional diversity for FZD7 during CRC morphogenesis.
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PMID:Frizzled-7 dictates three-dimensional organization of colorectal cancer cell carcinoids. 1701 32

DNA copy number changes represent molecular fingerprints of solid tumors and are as such relevant for better understanding of tumor development and progression. In this study, we applied genome-wide array comparative genomic hybridization (aCGH) to identify gene-specific DNA copy number changes in chromosomal (CIN)- and microsatellite (MIN)-unstable sporadic colorectal cancers (sCRC). Genomic DNA was extracted from microdissected, matching normal colorectal epithelium and invasive tumor cells of formalin-fixed and paraffin-embedded tissues of 22 cases with colorectal cancer (CIN = 11, MIN = 11). DNA copy number changes were determined by aCGH for 287 target sequences in tumor cell DNAs, using pooled normal DNAs as reference. aCGH data of tumor cell DNAs was confirmed by fluorescence in situ hybridization (FISH) for three genes on serial tissues as those used for aCGH. aCGH revealed DNA copy number changes previously described by metaphase CGH (gains 7, 8q, 13q, and 20q; losses 8p, 15q, 18q, and 17p). However, chromosomal regions 20q, 13q, 7, and 17p were preferentially altered in CIN-type tumors and included DNA amplifications of eight genes on chromosome 20q (TOP1, AIB1, MYBL2, CAS, PTPN1, STK15, ZNF217, and CYP24), two genes on chromosome 13q (BRCA2 and D13S25), and three genes on chromosome 7 (IL6, CYLN2, and MET) as well as DNA deletions of two genes on chromosome 17p (HIC1 and LLGL1). Finally, additional CIN-tumor-associated DNA amplifications were identified for EXT1 (8q24.11) and MYC (8q24.12) as well as DNA deletions for MAP2K5 (15q23) and LAMA3 (18q11.2). In contrast, distinct MIN-tumor-associated DNA amplifications were detected for E2F5 (8p22-q21.3), GARP (11q13.5-q14), ATM (11q22.3), KAL (Xp22.3), and XIST (Xq13.2) as well as DNA deletions for RAF1 (3p25), DCC (18q21.3), and KEN (21q tel). aCGH revealed distinct DNA copy number changes of oncogenes and tumor suppressor genes in CIN- and MIN-type sporadic colorectal carcinomas. The identified candidate genes are likely to have distinct functional roles in the carcinogenesis and progression of CIN- and MIN-type sporadic CRCs and may be involved in the differential response of CIN- and MIN-type tumor cells to (adjuvant) therapy, such as 5-fluorouracil.
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PMID:Array CGH identifies distinct DNA copy number profiles of oncogenes and tumor suppressor genes in chromosomal- and microsatellite-unstable sporadic colorectal carcinomas. 1714 21

Much information has been reported on the genetic and genomic alterations in colorectal cancer (CRC) in literature; however, nonrandom chromosomal alterations in Chinese CRC patients have only one report in Hong Kong. To further identify genomic alteration in primary sporadic colorectal carcinomas (SCRC) in Chinese patients and understand the molecular mechanisms in CRC development, progress, and metastasis, we used comparative genomic hybridization to screen for losses and/or gains of DNA copies along chromosomes in 24 SCRC tissues from 24 patients. Comparative genomic hybridization was applied to investigate the genomic imbalance in 24 cases of primary SCRC and compared the differences between tumors in different loci and between tumors with and without metastasis. The common chromosomal alterations in the SCRC included gains of chromosomes 1q, 2q, 4q, 7q, 8q, 11q, 13q, 20q and also losses of chromosomes 9p, 16q, 17p, 18q. Among them, gains of 1q, 7q, 20q and losses of 17p, 18q were related with lymph node metastasis of SCRC (P<0.05). The gains of 4q, 7q, 20q and losses of 9p, 18q were related with the sites (P<0.05), colon and rectum, respectively; gain of 20q and loss of 9p were commonly found in the colon cancer; gain of 4q, 7q and loss of 18q were easily seen in the rectal cancer. There are multiple regions of chromosomes with copy-number changes in SCRC. The tumor suppressor genes and oncogenes on these regions may be involved in the development and progress of SCRC. The chromosome 1q, 2q, 4q, 7q, 8q, 11q, 13q, 20q regions may have oncogenes such as epidermal growth factor, MET, platelet-derived growth factor receptor A, and 9p, 16q, 17p, 18q regions may have tumor suppressor genes such as p53,DCC, IGFR1 associated with occurrence of SCRC. The chromosome 1q, 7q, 20q, 17p, 18q regions may have genes related with metastasis of SCRC. The development mechanisms of colon cancer and rectal cancer may not be completely similar. Additionally, gain of chromosome 1q was verified by the second technique-Real-time reverse transcription PCR.
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PMID:Chromosomal alteration in Chinese sporadic colorectal carcinomas detected by comparative genomic hybridization. 1752 79

The constitutive activation of beta-catenin-dependent ('canonical') Wnt signalling is a necessary initiating event in the genesis of most colorectal cancers. As this constitutive activation occurs through genetic mutation of one of the down-stream components of the signalling pathway, it was presumed that additional regulation of beta-catenin-dependent Wnt signalling would be inconsequential. However, it is now recognised that additional modulation of beta-catenin-dependent Wnt signalling is involved in tumour progression, and many of the genes associated with tumour invasion and metastasis are beta-catenin/TCF transcriptional target genes that are dynamically regulated during cancer progression. Intriguingly, the demonstration that naturally occurring inhibitors of Wnt-Frizzled (FZD) interaction are bona fide tumour suppressors in this cancer suggests that additional modulation of Wnt signalling is via the upstream components of the pathway. This is corroborated by recent studies that demonstrate tumour-promoting roles for Wnt and FZD per se. Moreover, both beta-catenin-dependent and beta-catenin-independent Wnt/FZD-mediated signalling is implicated during the dynamic and reversible EMT and MET that underscore colorectal cancer progression. Importantly, therapeutic targeting of the Wnt signalling pathway at the plasma membrane is clearly indicated by the profound anti-tumour activity of small molecule inhibitors and dominant-negative receptor constructs that target the receptor complex. The potential to effectively target EMT and MET processes at the plasma membrane via the upstream components of the Wnt signalling pathway offers new hope for anti-cancer therapy.
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PMID:The upstream components of the Wnt signalling pathway in the dynamic EMT and MET associated with colorectal cancer progression. 1835 Feb 53

The impact of KRAS mutations on cetuximab sensitivity in epidermal growth factor receptor fluorescence in situ hybridisation-positive (EGFR FISH+) metastatic colorectal cancer patients (mCRC) has not been previously investigated. In the present study, we analysed KRAS, BRAF, PI3KCA, MET, and IGF1R in 85 mCRC treated with cetuximab-based therapy in whom EGFR status was known. KRAS mutations (52.5%) negatively affected response only in EGFR FISH+ patients. EGFR FISH+/KRAS mutated had a significantly lower response rate (P=0.04) than EGFR FISH+/KRAS wild type patients. Four EGFR FISH+ patients with KRAS mutations responded to cetuximab therapy. BRAF was mutated in 5.0% of patients and none responded to the therapy. PI3KCA mutations (17.7%) were not associated to cetuximab sensitivity. Patients overexpressing IGF1R (74.3%) had significantly longer survival than patients with low IGF1R expression (P=0.006), with no difference in response rate. IGF1R gene amplification was not detected, and only two (2.6%) patients, both responders, had MET gene amplification. In conclusion, KRAS mutations are associated with cetuximab failure in EGFR FISH+ mCRC, even if it does not preclude response. The rarity of MET and IGF1R gene amplification suggests a marginal role in primary resistance. The potential prognostic implication of IGF1R expression merits further evaluation.
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PMID:Primary resistance to cetuximab therapy in EGFR FISH-positive colorectal cancer patients. 1857 88

We identified a previously undescribed gene associated with colon cancer by genome-wide expression analysis in primary and metastatic carcinomas: metastasis-associated in colon cancer-1, MACC1. MACC1 expression in tumor specimens is an independent prognostic indicator of metastasis formation and metastasis-free survival. We show that the gene encoding the hepatocyte growth factor (HGF) receptor, MET, is a transcriptional target of MACC1. MACC1 promotes proliferation, invasion and HGF-induced scattering of colon cancer cells in cell culture and tumor growth and metastasis in mouse models. These phenotypes are lost in cells expressing MACC1 mutants lacking the SH3 domain or the proline-rich motif. For clinical practice, MACC1 will be useful for the identification of poor prognosis subjects with colorectal cancer and is a promising new target for intervention in metastasis formation.
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PMID:MACC1, a newly identified key regulator of HGF-MET signaling, predicts colon cancer metastasis. 1909 8

In an effort to improve the survival of cancer patients, new therapeutic approaches focusing on the molecular mechanisms that mediate tumour cell growth or survival have gained much attention. In particular, EGF-R and VEGF/VEGF-R have been extensively investigated as targets for anti-neoplastic therapy. Agents that selectively target EGF-R, erbB-2, VEGF-R-2 or VEGF have shown promising activity in clinical trials, and several are now approved for use in selected cancer indications. However, all patients ultimately develop resistance to these drugs. Thus, there is a great need to understand how patients become resistant to effective therapies for these cancers since this approach may lead to improvements in therapies that target EGF-R and VEGF/VEGF-R. Pre-clinical studies have begun to shed light on the mechanisms of resistance to anti-angiogenetic drugs and to date four mechanisms of resistance have been identified (1) upregulation of bFGF, (2) overexpression of MMP-9, (3) increased levels of SDF-1alpha and (4) HIF-1alpha-induced recruitment of bone marrow-derived CD45+ myeloid cells. In addition, the molecular mechanisms of resistance to EGF-R modulating agents can be attributed to several general processes: (1) activation of alternative tyrosine kinase inhibitors that bypass the EGF-R pathway (e.g. c-MET and IGF-1R), (2) increased angiogenesis, (3) constitutive activation of downstream mediators (e.g. PTEN and K-ras) and (4) the existence of specific EGF-R mutations. K-ras mutations have been significantly associated with a lack of response to EGF-R tyrosine kinase inhibitors in patients with NSCLC and with a lack of response to cetuximab or to panitumumab in patients with advanced colorectal cancer. The identification of these resistance mechanisms has led to clinical trials using newly designed targeted therapies that can overcome resistance and have shown promise in laboratory studies. Ongoing research efforts will likely continue to identify additional resistance mechanisms, and these findings will hopefully translate into effective therapies for different cancers.
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PMID:Resistance to EGF-R (erbB-1) and VEGF-R modulating agents. 1912 37


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