Linked Life Data

9354444

Source:http://linkedlifedata.com/resource/pubmed/id/9354444

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
1997-11-20
pubmed:abstractText
To evaluate the role of O6-alkylguanine-DNA alkyltransferase (AGT) in colon tumor chloroethylnitrosourea (CENU) resistance, AGT-deficient VACO 8 cells were transfected with a vector containing or lacking the human O6-methylguanine-DNA methyltransferase (MGMT) cDNA. VACO 8MGMT (V8MGMT) sublines possessed high levels of AGT activity in cell culture and were > 10-fold resistant to the CENU 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). V8MGMT cells, VACO 8neo cells, and mixtures of both were grown as xenografts in nude mice. MGMT expression in VACO 8 xenografts reflected the percentage of V8MGMT cells present in the tumor inoculum. Xenografts originally containing 0-10% V8MGMT cells were sensitive to BCNU, although partial resistance was observed as the percentage of V8MGMT cells increased. Tumors containing 30-100% V8MGMT cells were completely resistant to BCNU with no regressions and no growth delays. Pretreatment with O6-benzylguanine (BG) depleted tumor AGT activity for at least 6 h and sensitized xenografts containing 1 and 100% V8MGMT cells to BCNU. After BCNU or BG + BCNU, xenografts growing from inoculums containing as low as 0.1% V8MGMT cells had high AGT activities similar to that found in V8MGMT xenografts, with the majority of the cells expressing MGMT. These results provide evidence that MGMT expression influences both intrinsic and acquired colon tumor CENU resistance, that selective expansion of AGT+ colon tumor cells commonly occurs after CENU exposure, and that BG is effective in sensitizing colon tumors to CENUs, even when only a small fraction of the cells in a heterogeneous tumor express MGMT.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0008-5472
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
57
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4817-23
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
O6-methylguanine-DNA methyltransferase (MGMT) transfectants of a 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU)-sensitive colon cancer cell line selectively repopulate heterogenous MGMT+/MGMT- xenografts after BCNU and O6-benzylguanine plus BCNU.
pubmed:affiliation
Division of Hematology-Oncology, Case Western Reserve University, University Hospitals' Ireland Cancer Center, Cleveland, Ohio 44106-4937, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.