Differential recognition of mdr1a and mdr1b gene products in multidrug resistant mouse tumour cell lines by different monoclonal antibodies

Barrand, Margery A.; Twentyman, Peter R.

doi:10.1038/bjc.1992.48

Cited by 29 publications

(28 citation statements)

References 25 publications

(18 reference statements)

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“…With this antibody, P-glycoprotein was detected in membranes of the isolated microvessels (MV) (Fig. la and b) in amounts comparable to those found in MDR mouse tumour cell lines, EMT6/AR1.0 [16] and L 0.5. A moderate amount of P-glycoprotein was observed in membranes of endothelial cells cultured from the brain microvessels (BEC) (Fig.…”

Section: Resultsmentioning

confidence: 89%

“…1 a, b, e and f) and this was maintained through several passages (not shown). The monoclonal antibody, 265/F4, that detects the protein product of the mouse mdrlb gene but not that of the mdrla gene [16] did not recognise the P-glycoprotein in the brain microvessel membranes (MV) (Fig. lc) or in the AR1.0 cells (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…These included mouse mammary tumour cell lines, EMT6/P and the MDR variant, EMT6/ARI.0, which is maintained in 1.0/lg/ml doxorubicin and is known to contain only the P-glycoprotein isoform, mdrla [16]. Membrane protein of the mouse fibrosarcoma line, L0.5, which contains the P-glycoprotein isoform, mdrlb (Holmes, personal communication) was supplied by Ms. Julie Holmes of MRC Clinical Oncology Unit in Cambridge.…”

Section: Cell Andolation and Culturementioning

confidence: 99%

“…MDR and parent cell lines used as positive and negative controls were cultured as described [16]. These included mouse mammary tumour cell lines, EMT6/P and the MDR variant, EMT6/ARI.0, which is maintained in 1.0/lg/ml doxorubicin and is known to contain only the P-glycoprotein isoform, mdrla [16].…”

Section: Cell Andolation and Culturementioning

confidence: 99%

“…Membranes were prepared from isolated brain capillaries or from [16]), both at 100 ng/ml in Tris-buffered saline containing 2.5% bovine serum albumin and P-glycoprotein visualised using an ECL western blotting analysis system (Amersham Int. ).…”

Section: Western Blot Analysismentioning

confidence: 99%

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Comparisons of P‐glycoprotein expression in isolated rat brain microvessels and in primary cultures of endothelial cells derived from microvasculature of rat brain, epididymal fat pad and from aorta

1995

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In vivo expression of P-glycoprotein in isolated rat brain mierovessels is compared with that in vitro in primary cultures of brain endothelial cells. More P-glycoprotein is detected by Western immunoblotting in microvessels than in cultured endothelium. RT-PCR with isnform-specific primers and immunobiotting with a mdrlb-specific antibody reveals only mdrla in vivo but both mdrla and mdrlb in vitro. Thus mdrla decreases whereas mdrlb increases during culture. P-Glycoprotein activity is evident in vitro, with resistance modulators, e.g. verapamil, producing increases in intracenular [3H]vincristine accumulation. Endothelial cells cultured from epididymal fat pad microvaseulature and aorta contain little or no P-glycoprotein. Here, resistance modulators are less effective.

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Section: Resultsmentioning

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Section: Cell Andolation and Culturementioning

confidence: 99%

Section: Cell Andolation and Culturementioning

confidence: 99%

Section: Western Blot Analysismentioning

confidence: 99%

See 3 more Smart Citations

Comparisons of P‐glycoprotein expression in isolated rat brain microvessels and in primary cultures of endothelial cells derived from microvasculature of rat brain, epididymal fat pad and from aorta

1995

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Differential over‐expression of mdr1 genes in multidrug‐resistant rat glioblastoma cell lines selected with doxorubicin or vincristine

Schott

Bennis

Pourquier

et al. 1993

Intl Journal of Cancer

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We have compared the pharmacological and molecular characteristics of 2 cell lines derived from the C6 rat glioblastoma, and selected for resistance either to doxorubicin (C6 0.5 line) or to vincristine (C6 IV line). Each line displays a preferential 400-fold resistance towards the drug used for selection, the C6 IV line being especially weakly resistant to doxorubicin (13-fold). Verapamil completely restored doxorubicin sensitivity in the C6 IV line as well as vincristine resistance in the C6 0.5 line, but could not completely reverse doxorubicin resistance in the C6 0.5 line or vincristine resistance in the C6 IV line. This suggests that specific mechanisms of resistance against each drug were added to a common P-glycoprotein-mediated multidrug-resistance mechanism. Doxorubicin efflux was total within 2 hr in the C6 IV line, whereas it remained 8 to 10% of drug in the C6 0.5 line 4 hr after drug removal, despite a more rapid efflux of the drug in the first 30 min. This 2-compartment behavior could be related to a special sub-cellular distribution of doxorubicin in C6 0.5 cells. Northern and Western blot analysis of the mdrI gene and of the P-glycoprotein expressed by the 2 resistant cell lines made it possible to quantify their degree of over-expression; when compared with the C6 wild strain, the C6 0.5 line over-expressed both the mdrI gene and the P-glycoprotein to a slightly higher level than the C6 IV line. Northern and Western blot analysis also suggested that C6 0.5 cell preferentially over-expressed the mdrIa gene, whereas the C6 IV cells preferentially over-expressed the mdrIb gene. This differential over-expression was confirmed after polymerase-chain-reaction amplification of the cDNA sequences transcribed from total RNA extracted from the 2 lines. It can be concluded therefore that the mdrIa gene product is more efficient than the mdrIb gene product in extruding anti-cancer drugs from the cells; and that the mdrIb gene product might preferentially extrude vincristine rather than doxorubicin.

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Identification of a P-Glycoprotein-Deficient Subpopulation in the CF-1 Mouse Strain Using a Restriction Fragment Length Polymorphism

Umbenhauer

Lankas

Pippert

et al. 1997

Toxicology and Applied Pharmacology

107

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Differential recognition of mdr1a and mdr1b gene products in multidrug resistant mouse tumour cell lines by different monoclonal antibodies

Cited by 29 publications

References 25 publications

Comparisons of P‐glycoprotein expression in isolated rat brain microvessels and in primary cultures of endothelial cells derived from microvasculature of rat brain, epididymal fat pad and from aorta

Comparisons of P‐glycoprotein expression in isolated rat brain microvessels and in primary cultures of endothelial cells derived from microvasculature of rat brain, epididymal fat pad and from aorta

Differential over‐expression of mdr1 genes in multidrug‐resistant rat glioblastoma cell lines selected with doxorubicin or vincristine

Identification of a P-Glycoprotein-Deficient Subpopulation in the CF-1 Mouse Strain Using a Restriction Fragment Length Polymorphism

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