ABCP

Breast Cancer Resistance Protein (BCRP, also known as MXR or ABCP), first cloned from mitoxantrone and anthracycline-resistant breast and colon cancer cells [188, 189] is a half-transporter efflux pump believed to function as a homo-or hetero-dimer. Following its identification, BCRP-mediated drug resistance was observed for topoisomerase inhibitors including camptothecins [190, 191] and in-dolocarbazoles [192]. In normal tissues, BCRP was detected in placental syncytio-trophoblasts, hepatocyte canalicular membrane, apical intestinal epithelia and vascular endothelial cells [193]. These findings support the important role BCRP plays in modulating topotecan bioavailability, fetal exposure and hepatic elimination [194]. Considering that the substrates and tissue distributions for BCRP overlap somewhat with MDR1 and MRPs [195], additional studies will be required to define the relative contribution of each of these transporters in the overall and tis-... 

Maliepaard M, van Gastelen MA, de Jong LA, Pluim D, van Waardenburg RC, Ruevekamp-Helmers MC et al. Overexpression of the BCRP/MXR/ABCP gene in a topotecan-selected ovarian tumor cell line. Cancer Res 1999 ... 

From structural characterization of 48 by X-ray crystallography [31], it is suggested that formation of stable Ru 11,111- cluster derivative 47 or 48 is involved in substitution of the axially coordinated methanol as well as one of the six bridging acetates in the Ru ni ni precursor 2 by an abpy or abcp, in which formal oxidation state of the triruthenium species is converted from 111,111,111 to III,III,II. 

It appears that abpy- or abcp-substituted oxo-centered triruthenium derivatives exhibit a high stabilization on low-valence III,III,II and III,II,II species, which are usually unavailable through axial ligand substitution. The abpy or abcp exhibits a i-T 1(N),r 2(N,N) bonding mode, chelating one ruthenium center via azo N and pyridyl/pyrimidine N donors as well as bound to another ruthenium center via the other pyridyl/pyrimidine N donor. 

Ru3 /Ru3 , and Ru3 /Ru3 processes. The corresponding redox potentials in 48 show 0.12-0.30 V anodic shift compared with those in 47, probably due to the better 7t-accepting ability for pyrimidime-containing abcp than that for pyridyl-containing abpy. 

Fig. 8 Plots of cyclic voltammograms of abcp-substituted triruthenium species 48 and the parent triruthenium complex [Ru30(0Ac)6(py)3]+ in chloromethane solution of (Bu4N)(PFg), showing anodic shifts of redox potentials in 48 relative to those in [Ru30(0Ac)6(py)3] +...

A number of water- and fat-soluble nitrogen compounds, e.g., 2,2 -azo-fe/.v(2-amidinopropane) dihydrochloride (ABAP), 2,2 -azo-te(2,4-dimethylvaleroni-trile) (AMVN), and 2,2 -azo-to(2-cyanopropane) (ABCP), form free radicals during decomposition that in the sample to be investigated initiate lipid peroxidation [16] ... 

In contrast to P-gp and the MRP proteins, the breast cancer resistance protein (BCRP) contains six transmembrane domains and only one ATP-binding domain. It was first cloned from the breast cancer cell line MCF-7 selected in doxombicin, in the presence of the P-gp inhibitor verapamil. It is found in many human tissues, such as the placenta, small intestine, colon, and liver [133], It is localized to the apical membrane of epithelial cells of the small intestine and colon and to the bile canalicular membrane in the liver and is involved in reducing intestinal uptake, increasing hepatobiliary excretion, etc., leading to diminished oral bioavailability. cDNA sequences identical to BCRP and named MXR and ABCP, respectively, were independently isolated from human colon carcinoma cells and human placenta [134], BCRP requires... 

Honjo, Y., Hrycyna, C. A., Yan, Q. W., et al. (2001) Acquired mutations in the MXR/BCRP/ ABCP gene alter substrate specificity in MXR/BCRP/ABCP-overexpressing cells. Cancer Res. 61,6635-6639. 

Allen, J. D., Biinkhuis, R. F., Wijnholds, J., and Schinkel, A. H. (1999) The mouse Bcrpl/ Mxr/Abcp gene amplification and overexpression in cell lines selected for resistance to topo-tecan, mitoxantrone, or doxorubicin. Cancer Res. 59, 4237-4241. 

Bcrp Mouse Abcgl MXR ABCP 26357 - Small and large Liver CM,... 

Allikmets R, Schriml LM, Hutchinson A, et al. A human placenta-specific ATP-binding cassette gene (ABCP) on chromosome 4q22 that is involved in multidrug resistance. Cancer Res 1998 58 5337-5339. 

Interestingly, the same reagent removes S from abcPS with retention it is presumed that the first step is similar, but that SiCl3 then attacks sulfur, rather than phosphorus ... 

The American Board of Clinical Pharmacology (ABCP) http / / WWW.abcp.net/... 

BCRP ABCG2 ABCP, MXR Placenta, liver, intestine, apical membrane Apical Drug resistance... 

Rocchi, E., Khodjakov, A., Volk, E.L., Yang, C.H., Litman, T., Bates, S.E. et al. (2000) The product of the ABC half transporter gene ABCG2 (BCRP/MXR/ ABCP) is expressed in the plasma membrane. Biochemical and Biophysical Research Communications, 271, 42-46. 

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