کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9905148 1546579 2005 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Characterization of ABCG2 gene amplification manifesting as extrachromosomal DNA in mitoxantrone-selected SF295 human glioblastoma cells
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی تحقیقات سرطان
پیش نمایش صفحه اول مقاله
Characterization of ABCG2 gene amplification manifesting as extrachromosomal DNA in mitoxantrone-selected SF295 human glioblastoma cells
چکیده انگلیسی
The human ABCG2 gene, located on chromosome 4, encodes an ATP-binding cassette half-transporter that has been shown to confer resistance to chemotherapeutic agents. Relatively little is known about the mechanisms controlling expression of ABCG2. In previous studies, we had shown that overexpression of ABCG2 can result from rearrangement or gene amplification involving chromosome 4. To better characterize the mechanisms of ABCG2 overexpression, SF295 glioblastoma cells were exposed to increasing amounts of mitoxantrone to generate the SF295 MX50, MX100, MX250, and MX500 sublines, maintained in mitoxantrone concentrations ranging from 50 to 500 nmol/L. Northern blot analysis confirmed overexpression of ABCG2 mRNA, and immunoblot analysis demonstrated increased protein expression in the selected cell lines. Efflux of BODIPY-prazosin confirmed a functional protein. ABCG2 gene amplification was observed in all resistant sublines, as determined by Southern blot analysis. Fluorescence in situ hybridization (FISH) revealed amplification of ABCG2 via double minute chromosomes (dmins) detected in metaphase chromosome spreads in the SF295 MX50 and MX100 sublines. At higher levels of drug selection, in the MX250 and MX500 sublines, fewer dmins were observed but homogeneously staining regions (hsr) were visible with FISH analysis, revealing reintegration of the ABCG2 gene into multiple chromosomes. Spectral karyotyping (SKY) demonstrated multiple clonal and nonclonal rearrangements of chromosome 4, including hsrs. These results suggest that amplification of ABCG2 occurred initially in the form of dmins, followed by chromosomal reintegration of the amplicon at multiple sites. This occurred with increasing drug-selection pressure, generating a more stable genotype.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Cancer Genetics and Cytogenetics - Volume 160, Issue 2, 15 July 2005, Pages 126-133
نویسندگان
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