Liver metastasis models of colon cancer for evaluation of drug efficacy using NOD/Shi-scid IL2Rγnull (NOG) mice

Hamada, Kenji; Monnai, Makoto; Kawai, Kenji; Nishime, Chiyoko; Kito, Chika; Miyazaki, Noriyuki; Ohnishi, Yasuyuki; Nakamura, Masato; Suemizu, Hiroshi

doi:10.3892/ijo.32.1.153

Cited by 39 publications

(54 citation statements)

References 34 publications

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“…Five and four exons of human POLD1 and POLE genes, respectively, that encompass the genomic regions encoding the 3¢ exonuclease, that is, proofreading, domains of pol delta and epsilon were amplified by PCR and sequenced by direct cycle sequencing (Figure 1a and b). Sequence alterations causing amino-acid substitutions were identified in two cell lines and one tissue sample ( Figure 2, Table 2), [36][37][38][39][40][41][42][43] and these sequence alterations were confirmed in three independently amplified PCR products by more than three cycle sequencing reactions. Other types of sequence alterations such as insertions/deletions were not found.…”

Section: Resultsmentioning

confidence: 99%

Concurrent genetic alterations in DNA polymerase proofreading and mismatch repair in human colorectal cancer

et al. 2010

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Genomic sequences encoding the 3¢ exonuclease (proofreading) domains of both replicative DNA polymerases, pol delta and pol epsilon, were explored simultaneously in human colorectal carcinomas including six established cell lines. Three unequivocal sequence alterations, including one previously reported, were found, and all these were considered as dysfunctional mutations in light of the local amino-acid sequences. In particular, the F367S mutation found in the POLE gene encoding the pol epsilon catalytic subunit, which includes the proofreading domain, is the first found in human diseases. Surprisingly, the tumours carrying these proofreading domain mutations were all defective in DNA mismatch repair (MMR). In addition to the two cell lines with acknowledged MMR gene mutations, the third tumour was also demonstrated to harbour a distinct mutation in MLH1, and indeed exhibited a microsatellite-unstable phenotype. These findings suggest that, in concert with MMR deficiency, defective polymerase proofreading may also contribute to the mutator phenotype observed in human colorectal cancer. Our observations may suggest previously unrecognised complexities in the molecular abnormalities underlying the mutator phenotype in human neoplasms. Keywords: polymerase delta; polymerase epsilon; proofreading domain; colorectal cancer INTRODUCTION Mutation rates on the genome are invariably regulated and typically suppressed to an extremely low level, such as 10 À10 per base replicated, in the organisms. 1 The high fidelity of DNA replication is achieved by several molecular mechanisms. The frequency of erroneous nucleotide incorporation is indeed extremely low compared with that expected from base-pairing energetics, and the vast reduction of the misincorporation frequency involves three steps of molecular events: (a) correct incorporation of complementary nucleotides by DNA polymerases, (b) removal of the newly added nucleotides, particularly incorrectly paired nucleotides, by the 3¢ exonuclease activities associated with the DNA polymerases (proofreading) and (c) postreplicative scanning of mispaired bases by DNA mismatch repair (MMR). 2,3 Various Escherichia coli (E. coli) mutator strains have been used to study these molecular mechanisms by which organisms maintain their mutation rates at very low levels. The dnaQ + (mutD + ) gene of E. coli encodes the epsilon subunit of the DNA polymerase III holoenzyme that is involved in 3¢ exonuclease proofreading activity, 4 and, therefore, the mutation frequencies in the dnaQ mutators are sometimes 1000-10 000 times higher than the wild-type levels. 4,5 In E. coli, MMR is chiefly directed by the proteins encoded by the three genes: mutS + , mutL + and mutH + . 6 The mutS or mutL mutators exhibit an approximately 100 times increase in the mutation frequency. 7 Thus, polymerase proofreading and MMR are the two major

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Section: Resultsmentioning

confidence: 99%

Concurrent genetic alterations in DNA polymerase proofreading and mismatch repair in human colorectal cancer

et al. 2010

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“…sanger.ac.uk/) and in previous studies (26)(27)(28). Particularly, SW48 and T3M4 cells have a wild-type K-Ras gene.…”

Section: Characterization Of a Panel Of Colorectal And Pancreatic Canmentioning

confidence: 99%

Toll-like Receptor 9 Agonist IMO Cooperates with Cetuximab in K-Ras Mutant Colorectal and Pancreatic Cancers

Rosa

Melisi

Damiano

et al. 2011

Clinical Cancer Research

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Purpose: K-Ras somatic mutations are a strong predictive biomarker for resistance to epidermal growth factor receptor (EGFR) inhibitors in patients with colorectal and pancreatic cancer. We previously showed that the novel Toll-like receptor 9 (TLR9) agonist immunomodulatory oligonucleotide (IMO) has a strong in vivo activity in colorectal cancer models by interfering with EGFR-related signaling and synergizing with the anti-EGFR monoclonal antibody cetuximab.Experimental Design: In the present study, we investigated, both in vitro and in vivo, the antitumor effect of IMO alone or in combination with cetuximab in subcutaneous colon and orthotopic pancreatic cancer models harboring K-Ras mutations and resistance to EGFR inhibitors.Results: We showed that IMO was able to significantly restore the sensitivity of K-Ras mutant cancer cells to cetuximab, producing a marked inhibition of cell survival and a complete suppression of mitogenactivated protein kinase phosphorylation, when used in combination with cetuximab. IMO interfered with EGFR-dependent signaling, modulating the functional interaction between TLR9 and EGFR. In vivo, IMO plus cetuximab combination caused a potent and long-lasting cooperative antitumor activity in LS174T colorectal cancer and in orthotopic AsPC1 pancreatic cancer. The capability of IMO to restore cetuximab sensitivity was further confirmed by using K-Ras mutant colorectal cancer cell models obtained through homologous recombination technology.Conclusions: We showed that IMO markedly inhibits growth of K-Ras mutant colon and pancreatic cancers in vitro and in nude mice and cooperates with cetuximab via multiple mechanisms of action. Therefore, we propose IMO plus cetuximab as a therapeutic strategy for K-Ras wild-type as well for K-Ras mutant, cetuximab-resistant colorectal and pancreatic cancers.

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“…Colorectal cancer cell lines were HT29, WiDr, SW48, and COLO201 (American Type Culture Collection, Manassas, VA). HT29 and WiDr are reported to have high metastatic potency (23). SW48 and COLO201 are reported to have low metastatic potency (23).…”

Section: Analysis Of Mrna By Reverse-transcription Polymerase Chain Rmentioning

confidence: 99%

Significance of monocyte chemoattractant protein-1 in angiogenesis and survival in colorectal liver metastases

Yoshidome

Kohno²,

Sugiyama³

et al. 2009

Int J Oncol

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Abstract. Monocyte chemoattractant protein-1 (MCP-1) has been demonstrated to play a role in tumor progression. The present study examined the MCP-1 expression of colorectal liver metastases and determined whether MCP-1 is related to tumor progression and is a predictive marker for survival after hepatic resection of colorectal liver metastases. Eightyseven patients with colorectal liver metastases were evaluated by immunohistochemistry of MCP-1, Angiopoietin-2, CD68, and CD34 for determination of microvessel density. Clinicopatholgical data were also examined. In a separate experiment, immunohistochemistry of MCP-1 was performed to investigate the expression of primary colorectal tumor according to the clinical stage. MCP-1 mRNA expression was determined in colorectal cancer cell lines. Forty-nine patients (56%) showed high expression of MCP-1 of colorectal liver metastases. High MCP-1 expression was related to multiple colorectal liver metastases. When the degree of MCP-1 expression increased, microvessel density count significantly increased compared with low MCP-1 expression. The MCP-1 expression correlated with Angiopoietin-2 expression. MCP-1 expression of the primary colorectal cancer increased as the clinical stage advanced. The increased MCP-1 mRNA expression was observed in cancer cell lines which have high metastasis potency. Univariate analysis demonstrated that the timing of metastases, tumor size, number of metastases, and MCP-1 expression were significant prognostic factors. Multivariate analysis demonstrated that MCP-1 expression was a significant prognostic factor in hepatic disease-free survival. The MCP-1 expression in colorectal liver metastases, at least in part, may be associated with angiogenesis and be a predictive marker for hepatic recurrence after hepatic resection for colorectal liver metastases.

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Liver metastasis models of colon cancer for evaluation of drug efficacy using NOD/Shi-scid IL2Rγnull (NOG) mice

Cited by 39 publications

References 34 publications

Concurrent genetic alterations in DNA polymerase proofreading and mismatch repair in human colorectal cancer

Concurrent genetic alterations in DNA polymerase proofreading and mismatch repair in human colorectal cancer

Toll-like Receptor 9 Agonist IMO Cooperates with Cetuximab in K-Ras Mutant Colorectal and Pancreatic Cancers

Significance of monocyte chemoattractant protein-1 in angiogenesis and survival in colorectal liver metastases

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