Selection and characterization of a high-activity ribozyme directed against the antineoplastic drug resistance–associated ABC transporter BCRP/MXR/ABCG2

Kowalski, Petra; Wichert, Anke; Holm, Per Sonne; Dietel, Manfred; Lage, Hermann

doi:10.1038/sj.cgt.7700294

Cited by 18 publications

(17 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Modulation of the BCRP multidrug-resistant phenotype by a hammerhead ribozyme directed against the transporter has recently been reported (Kowalski et al, 2002(Kowalski et al, , 2001. When the anti-BCRP hammerhead ribozyme was introduced into the human gastric carcinoma cell line EPG85-257RNOV, the levels of BCRP mRNA and protein were greatly reduced and cellular accumulation of BCRP substrate drugs was increased.…”

Section: Gene Therapy Approaches To Modulating Bcrpmentioning

confidence: 99%

See 1 more Smart Citation

Multidrug resistance mediated by the breast cancer resistance protein BCRP (ABCG2)

2003

View full text Add to dashboard Cite

Observations of functional adenosine triphosphate (ATP)-dependent drug efflux in certain multidrug-resistant cancer cell lines without overexpression of P-glycoprotein or multidrug resistance protein (MRP) family members suggested the existence of another ATP-binding cassette (ABC) transporter capable of causing cancer drug resistance. In one such cell line (MCF-7/AdrVp), the overexpression of a novel member of the G subfamily of ABC transporters was found. The new transporter was termed the breast cancer resistance protein (BCRP), because of its identification in MCF-7 human breast carcinoma cells. BCRP is a 655 amino-acid polypeptide, formally designated as ABCG2. Like all members of the ABC G (white) subfamily, BCRP is a half transporter. Transfection and enforced overexpression of BCRP in drug-sensitive MCF-7 or MDA-MB-231 cells recapitulates the drug-resistance phenotype of MCF-7/AdrVp cells, consistent with current evidence suggesting that functional BCRP is a homodimer. BCRP maps to chromosome 4q22, downstream from a TATA-less promoter. The spectrum of anticancer drugs effluxed by BCRP includes mitoxantrone, camptothecin-derived and indolocarbazole topoisomerase I inhibitors, methotrexate, flavopiridol, and quinazoline ErbB1 inhibitors. Transport of anthracyclines is variable and appears to depend on the presence of a BCRP mutation at codon 482. Potent and specific inhibitors of BCRP are now being developed, opening the door to clinical applications of BCRP inhibition. Owing to tissue localization in the placenta, bile canaliculi, colon, small bowel, and brain microvessel endothelium, BCRP may play a role in protecting the organism from potentially harmful xenobiotics. BCRP expression has also been demonstrated in pluripotential 'side population' stem cells, responsible for the characteristic ability of these cells to exclude Hoechst 33342 dye, and possibly for the maintenance of the stem cell phenotype. Studies are emerging on the role of BCRP expression in drug resistance in clinical cancers. More prospective studies are needed, preferably combining BCRP protein or mRNA quantification with functional assays, in order to determine the contribution of BCRP to drug resistance in human cancers.

show abstract

Section: Gene Therapy Approaches To Modulating Bcrpmentioning

confidence: 99%

“…Another way of revising BCRP-mediated resistance is to cleave the protein specifically using hammerhead ribozymes. A specific high-activity ribozyme directed at BCRP has recently been developed and found to cleave BCRP mRNA efficiently in a cell-free system (Kowalski et al, 2001(Kowalski et al, , 2002.…”

Section: Unanswered Questions and Pending Studiesmentioning

confidence: 99%

Multidrug resistance mediated by the breast cancer resistance protein BCRP (ABCG2)

2003

View full text Add to dashboard Cite

show abstract

“…The ribozyme's catalytic activity was previously characterized in a cell -free system. 20 The RzB1 -encoding sense and antisense oligodeoxynucleotides (RzB1 sense: 5 0 -CTG GAA CTG ATG AGT CCG TGA GGA CGA AAC ATC TGG AGA -3 0 ; RzB1 antisense: 5 0 -CTC CAG ATG TTT CGT CCT CAC GGA CTC ATC AGT TCC AGA -3 0 ) were synthesized chemically with overhanging A -ends. The coding and the corresponding strands (each at 50 M ) were hybridized for 10 minutes at 608C, and cloned into the multiple cloning side of a prepared T-tailed pcDNA3.1 vector provided in the eukaryotic TOPO TA Cloning Kit ( Invitrogen).…”

Section: Construction Of a Ribozyme And Control Expression Vector Sysmentioning

confidence: 99%

“…Recent studies revealed a high catalytic activity of the ribozyme RzB1 in a cell -free system. 20 As controls, two further expression vectors were constructed in the same way, but containing the following modifications: one vector was designed with the anti -BCRP ribozyme RzB1 -encoding sequence in antisense orientation to the CMV promoter; the other sense -oriented ribozyme insert contains two point mutations (Fig 1) that completely inhibit the ribozyme's cleavage activity (G 5 !U and A 14 !C). 18,29 Stable expression of the hammerhead ribozymes in the transfected clones was confirmed by RT-PCR ( Fig 2A ).…”

Section: Expression Of the Anti -Bcrp Ribozyme Rzb1 In Atypical Mdr Cmentioning

confidence: 99%

“…20 The in vitro characterization of the anti -BCRP hammerhead ribozyme RzB1 revealed a high endoribonucleolytic activity in a cell -free system. In the present work, we report the design and insertion of this anti -BCRP hammerhead ribozyme into a eukaryotic expression vector and the implementation of this construct into the BCRP -overexpressing human gastric carcinoma cell line, EPG85 -257RNOV ( 257RNOV ).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Modulation of the atypical multidrug-resistant phenotype by a hammerhead ribozyme directed against the ABC transporter BCRP/MXR/ABCG2

et al. 2002

Self Cite

View full text Add to dashboard Cite

The phenomenon of multidrug resistance ( MDR ) in human cancers is one of the major causes of failure of chemotherapy. A recently identified new member of the superfamily of ATP -binding cassette transporters, breast cancer resistance protein ( BCRP ), was demonstrated to confer an atypical multidrug -resistant phenotype to tumor cells. To overcome the BCRP -mediated drug resistance, a specific anti -BCRP hammerhead ribozyme was introduced into the human gastric carcinoma cell line, EPG85 -257RNOV, exhibiting an atypical MDR phenotype. By this approach, the expression levels of the targeted BCRP -encoding mRNA and the BCRP transport protein were decreased to the low constitutive expression level that was observed in highly drug -sensitive parental gastric carcinoma cells. In addition, in the anti -BCRP ribozyme -treated cells, the cellular drug accumulation was dramatically increased to the level measured in drug -sensitive cells. These effects were accompanied by an extensive reversal of the drug -resistant phenotype of more than 80%. Because additional mechanisms contribute to the multimodal -mediated MDR phenotype exhibited by this gastric carcinoma cell line, the data suggest that the BCRP -mediated contingent to the drug resistance was overcome nearly completely. Moreover, the data indicate that ribozyme -based gene therapy may be clinically applicable in preventing and reversing BCRPmediated atypical MDR.

show abstract

ABCG2 (BCRP) expression in normal and malignant hematopoietic cells

Abbott

2003

Hematological Oncology

View full text Add to dashboard Cite

ABCG2 (BCRP) is a member of the ATP-binding cassette (ABC) family of cell surface transport proteins. ABCG2 expression occurs in a variety of normal tissues, and is relatively limited to primitive stem cells. ABCG2 expression is associated with the side population (SP) phenotype of Hoechst 33342 efflux. The substrate profile of ABCG2 includes the antineoplastic drugs primarily targeting topoisomerases, including anthracyclines and camptothecins. More recently, pheophorbide, a chlorophyll-breakdown product, and protoporhyrin IX have been described as ABCG2 substrates, perhaps indicating a physiologic role of cytoprotection of primitive cells. Also, mice lacking ABCG2 expression have no intrinsic stem cell defects, although there is a remarkable increase in toxicity with antineoplastic drugs that are ABCG2 substrates, and also a photosensitivity resembling protoporphyria. Like other members of the ABC family, such as MDR1 and MRP1, ABCG2 is expressed in a variety of malignancies. Despite numerous reports of ABCG2 expression in AML, there is little evidence that ABCG2 expression is correlated with an adverse clinical outcome. This review will focus on the potential usefulness of ABCG2 as a marker primitive stem cells and possible physiologic roles of ABCG2 in protection of primitive stem cell populations, and potential methods of overcoming ABCG2-associated drug resistance in anticancer therapy.

show abstract

Selection and characterization of a high-activity ribozyme directed against the antineoplastic drug resistance–associated ABC transporter BCRP/MXR/ABCG2

Cited by 18 publications

References 17 publications

Multidrug resistance mediated by the breast cancer resistance protein BCRP (ABCG2)

Multidrug resistance mediated by the breast cancer resistance protein BCRP (ABCG2)

Modulation of the atypical multidrug-resistant phenotype by a hammerhead ribozyme directed against the ABC transporter BCRP/MXR/ABCG2

ABCG2 (BCRP) expression in normal and malignant hematopoietic cells

Contact Info

Product

Resources

About