Modulating the Folding of P-Glycoprotein and Cystic Fibrosis Transmembrane Conductance Regulator Truncation Mutants with Pharmacological Chaperones

Wang, Ying; Loo, Tip W.; Bartlett, M. Claire; Clarke, David M.

doi:10.1124/mol.106.029926

Cited by 80 publications

(78 citation statements)

References 39 publications

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“…In related studies, we showed in pulsechase experiments that Corr-4a increased accumulation of CFTRV232D due to an increase in folding efficiency and not increased expression (9). In addition, we found that VRT-532, a compound identified as a potentiator of CFTR P o , was associated with a modest increase in CFTRV232D band C expression, as was reported for CFTR⌬F508 (27). Importantly, the CFTRV232D trafficking defect was surmounted by Corr-4a treatment, with the folded protein achieving CFTR expression levels in HEK-293 cells.…”

Section: Resultssupporting

confidence: 49%

“…Treatment with Corr-4a increased CFTRV232D protein expression and channel activity to levels that were similar to those of CFTR. Moreover, 4-methyl-2-(5-phenyl-1H-pyrazol-3-yl)-phenol (VRT-532), a channel potentiator (27), reversibly increased CFTRV232D channel activity in perfused inside-out patches. Thus CF caused by defective folding of rare CFTR mutants might be treated with existing CFTR modulators.…”

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confidence: 99%

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Increased folding and channel activity of a rare cystic fibrosis mutant with CFTR modulators

Caldwell

Grove

Houck

et al. 2011

American Journal of Physiology-Lung Cellular and Molecular Phys

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Cystic fibrosis (CF) is a lethal recessive genetic disease caused by mutations in the CFTR gene. The gene product is a PKA-regulated anion channel that is important for fluid and electrolyte transport in the epithelia of lung, gut, and ducts of the pancreas and sweat glands. The most common CFTR mutation, ΔF508, causes a severe, but correctable, folding defect and gating abnormality, resulting in negligible CFTR function and disease. There are also a large number of rare CF-related mutations where disease is caused by CFTR misfolding. Yet the extent to which defective biogenesis of these CFTR mutants can be corrected is not clear. CFTRV232D is one such mutant that exhibits defective folding and trafficking. CFTRΔF508 misfolding is difficult to correct, but defective biogenesis of CFTRV232D is corrected to near wild-type levels by small-molecule folding correctors in development as CF therapeutics. To determine if CFTRV232D protein is competent as a Cl− channel, we utilized single-channel recordings from transfected human embryonic kidney (HEK-293) cells. After PKA stimulation, CFTRV232D channels were detected in patches with a unitary Cl− conductance indistinguishable from that of CFTR. Yet the frequency of detecting CFTRV232D channels was reduced to ∼20% of patches compared with 60% for CFTR. The folding corrector Corr-4a increased the CFTRV232D channel detection rate and activity to levels similar to CFTR. CFTRV232D-corrected channels were inhibited with CFTRinh-172 and stimulated fourfold by the CFTR channel potentiator VRT-532. These data suggest that CF patients with rare mutations that cause CFTR misfolding, such as CFTRV232D, may benefit from treatment with folding correctors and channel potentiators in development to restore CFTRΔF508 function.

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Section: Resultssupporting

confidence: 49%

mentioning

confidence: 99%

Increased folding and channel activity of a rare cystic fibrosis mutant with CFTR modulators

Caldwell

Grove

Houck

et al. 2011

American Journal of Physiology-Lung Cellular and Molecular Phys

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“…The P-gp is a heavy glycosylated transmembrane transporter that appears as a double band, a mature fully glycosylated species ($180 kDa) and a core-glycosylated species ($140 kDa). 32,33 We observed not only a direct inhibitory effect on P-gpmediated calcein transport but also a regulatory effect of statins on the protein level of P-gp (Figs. 6 and 7).…”

Section: Cancer Cell Biologymentioning

confidence: 92%

Double impact on p‐glycoprotein by statins enhances doxorubicin cytotoxicity in human neuroblastoma cells

Sieczkowski

Lehner

Ambros³

et al. 2009

Intl Journal of Cancer

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The development of multidrug resistance (MDR) is a major problem during cancer treatment. Drug efflux via ATP-binding cassette (ABC) transporters is the main mechanism responsible for resistance to chemotherapeutics. We have recently observed that statins enhance susceptibility to doxorubicin-induced apoptosis in human rhabdomyosarcoma cells, which is now also observed in human SH-SY5Y neuroblastoma cells. We have therefore investigated the ABC transporter activity to confirm a possible inhibition by statins in SH-SY5Y cells. Indeed, simvastatin directly inhibited dye transport at equimolar concentrations of the ABC transporter inhibitor, verapamil. Making use of the fluorescence behavior of doxorubicin the accumulation of anthracycline was monitored in real-time confocal microscopy. The intracellular doxorubicin accumulation was immediately enhanced by statins in SH-SY5Y cells and also in a MYCN-amplified neuroblastoma cell line STA-NB-10. The heavily glycosylated P-glycoprotein (ABCB1, P-gp) transporter appeared as a 180-and 140-kDa species. Atorvastatin and simvastatin reduced the 180-kDa form of P-gp, but not verapamil. Thereby the fully glycosylated species is shifted to the core glycosylated species (140 kDa), which was only seen at statin exposure times longer than 24 hr. The functional importance of glycosylation of the transporter was highlighted by exogenous application of N-glycosidase F, which was sufficient to enhance doxorubicin accumulation. Hence, these novel findings of statins' dual impact on P-gp have clinical implications. The enhanced intracellular accumulation of chemotherapeutics or other ABC transporter substrates in the presence of statins may represent a novel concept to overcome MDR in cancer therapy and improve drug safety.Neuroblastoma is the most common solid tumor in early childhood. About 55% of patients older than 1 year already have metastases at the time of diagnosis and therefore have a poor survival rate despite intensive therapy. 1 In $20% of the neuroblastoma a MYCN oncogene amplification occurs, which is the most unfavorable prognostic factor. 2,3 The MYCN amplification is the best established clinical and biological marker, which allows determination of the prognosis of the tumor, with numerous reports confirming the association with rapid tumor progression, advanced clinical stage and poor outcome. 3,4 Studies have shown that the expression of the multidrug resistance-associated protein 1 (MRP1, ABCC1) in neuroblastoma also correlates with poor clinical outcome and prognosis. 5,6 Recently, a prospective study has provided further evidence that high levels of MRP1 expression are strongly associated with MYCN oncogene amplification and predictive of poor outcome. 7 ATP-binding cassette (ABC) transporters, also termed multidrug resistance (MDR) proteins, play an important role in the efflux of many drugs. 8,9 Moreover, these ABC transporters are overexpressed in a wide range of tumors, for example, colon, kidney, adrenocortical or hepatocellular carcinomas, and thereby conf...

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“…It is more likely that altered N-glycans associated with several different proteins affect the drug-resistance mechanisms. P-gp is a heavy N-glycosylated transmembrane transporter that appears as a double band (28,29). Glycosylation of P-gp is important for appropriate protein folding and plasma membrane export.…”

Section: Figmentioning

confidence: 99%

Functional roles of glycogene and N‐glycan in multidrug resistance of human breast cancer cells

Xing

et al. 2013

IUBMB Life

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Drug resistance is a major problem in cancer chemotherapy. Aberrant glycosylation has been known to be associated with cancer chemoresistance. Aim of this work is to investigate the alterations of glycogene and N-glycan involved in multidrug resistance (MDR) in human breast cancer cell lines. Using real-time polymerase chain reaction (PCR) for quantification of glycogenes, fluorescein isothiocyanate (FITC)-lectin binding for glycan profiling, and mass spectrometry for N-glycan composition, the expression of glycogenes, glycan profiling, and N-glycan composition differed between drug-resistant MCF/ ADR cells and the parental MCF-7 line. Further analysis of the N-glycan regulation by tunicamycin (TM) application or PNGase F treatment in MCF/ADR cells showed partial inhibition of the N-glycan biosynthesis and increased sensitivity to chemotherapeutic drugs dramatically both in vitro and in vivo. Using an RNA interference strategy, we showed that the downregulation of MGAT5 in MCF/ADR cells could enhance the chemosensitivity to antitumor drugs both in vitro and in vivo. Conversely, a stable high expression of MGAT5 in MCF-7 cells could increase resistance to chemotherapeutic drugs both in vitro and in vivo. In conclusion, the alterations of glycogene and N-glycan in human breast cancer cells correlate with tumor sensitivity to chemotherapeutic drug and have significant implications for the development of new treatment strategies. V C 2013 IUBMB Life, 65(5): 409-422, 2013.

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Modulating the Folding of P-Glycoprotein and Cystic Fibrosis Transmembrane Conductance Regulator Truncation Mutants with Pharmacological Chaperones

Cited by 80 publications

References 39 publications

Increased folding and channel activity of a rare cystic fibrosis mutant with CFTR modulators

Increased folding and channel activity of a rare cystic fibrosis mutant with CFTR modulators

Double impact on p‐glycoprotein by statins enhances doxorubicin cytotoxicity in human neuroblastoma cells

Functional roles of glycogene and N‐glycan in multidrug resistance of human breast cancer cells

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