Synthesis and Application of Fluorescein‐ and Biotin‐Labeled Molecular Probes for the Chemokine Receptor CXCR4

Oishi, Shinya; Masuda, Ryo; Evans, Barry J.; Ueda, Satoshi; Goto, Yukiko; Ohno, Hiroaki; Hirasawa, Akira; Tsujimoto, Gozoh; Wang, Zixuan; Peiper, Stephen C.; Naito, Toshio; Kodama, Eiichi; Matsuoka, Masao; Fujii, Nobutaka

doi:10.1002/cbic.200700761

Cited by 37 publications

(64 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the model shown in Figure 1 the luminescent Ir III label does not appear to interfere with receptor binding, as the conjugation site in the peptide (d-Lys8) is distant from the pharmacophore, which consists of peptide residues 2, 3, 5 and 14. [10,11] Moreover, attachment of one or two additional Ac-TZ14011 moieties to the Ir III complex via a b-alanine spacer also does not appear to hinder the binding (Figure 1). …”

Section: Designmentioning

confidence: 92%

“…[8,9] For CXCR4 targeting several peptidic probes have been reported, including the cyclic Ac-TZ14011 peptide, and also a chelate-based fluorescent probe. [10][11][12][13][14][15][16] Transition-metal complexes based on, for example, iridium-(III), rhenium(I) and ruthenium(II) are attaining significant interest for application in imaging. [17][18][19][20][21][22][23][24][25][26][27][28] These phosphorescent metal complexes often posses better photophysical properties than organic fluorophores, such as long luminescence lifetimes.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Peptide‐Functionalized Luminescent Iridium Complexes for Lifetime Imaging of CXCR4 Expression

et al. 2011

View full text Add to dashboard Cite

The chemokine receptor 4 (CXCR4) is over-expressed in 23 types of cancer in which it plays a role in, among others, the metastatic spread. For this reason it is a potential biomarker for the field of diagnostic oncology. The antagonistic Ac-TZ14011 peptide, which binds to CXCR4, has been conjugated to luminescent iridium dyes to allow for CXCR4 visualization. The iridium dyes are cyclometalated octahedral iridium(III) 2-phenylpyridine complexes that can be functionalized with one, two or three targeting Ac-TZ14011 peptides. Confocal microscopy and fluorescence lifetime imaging microscopy (FLIM) showed that the peptide-iridium complex conjugates can be used to visualize CXCR4 expression in tumor cells. The CXCR4 receptor affinity and specific cell binding of the mono-, di- and trimeric peptide derivatives were assessed by using flow cytometry. The three derivatives possessed nanomolar receptor affinity and could distinguish between cell lines with different CXCR4 expression levels. This yields the first example of a neutral iridium(III) complex functionalized with peptides for FLIM-based visualization of a cancer associated membrane receptor.

show abstract

Section: Designmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Peptide‐Functionalized Luminescent Iridium Complexes for Lifetime Imaging of CXCR4 Expression

et al. 2011

View full text Add to dashboard Cite

show abstract

“…However, previous work with different T140 analogues (20) and the recent findings that the small molecule FC131 does not bind to CXCR7 (21) and does not induce arrestin recruitment to CXCR7 5 indicate that CXCR4 inhibitors do not inherently also bind CXCR7 and that receptor selectivity can be achieved. To our knowledge, synthetic chemokine receptor ligands that exert opposite effects on two different receptors are still unreported.…”

Section: Discussionmentioning

confidence: 99%

The Peptidomimetic CXCR4 Antagonist TC14012 Recruits β-Arrestin to CXCR7

Gravel

Malouf

Boulais

et al. 2010

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

CXCR7 is an atypical chemokine receptor that signals through ␤-arrestin in response to agonists without detectable activation of heterotrimeric G-proteins. Its cognate chemokine ligand CXCL12 also binds CXCR4, a chemokine receptor of considerable clinical interest. Here we report that TC14012, a peptidomimetic inverse agonist of CXCR4, is an agonist on CXCR7. The potency of ␤-arrestin recruitment to CXCR7 by TC14012 is much higher than that of the previously reported CXCR4 antagonist AMD3100 and differs only by one log from that of the natural ligand CXCL12 (EC 50 350 nM for TC14012, as compared with 30 nM for CXCL12 and 140 M for AMD3100). Moreover, like CXCL12, TC14012 leads to Erk 1/2 activation in U373 glioma cells that express only CXCR7, but not CXCR4. Given that with TC14012 and AMD3100 two structurally unrelated CXCR4 antagonists turn out to be agonists on CXCR7, this likely reflects differences in the activation mechanism of the arrestin pathway by both receptors. To identify the receptor domain responsible for these opposed effects, we investigated CXCR4 and CXCR7 C terminus-swapping chimeras. Using quantitative bioluminescence resonance energy transfer, we find that the CXCR7 receptor core formed by the seven-transmembrane domains and the connecting loops determines the agonistic activity of both TC14012 and AMD3100. Moreover, we find that the CXCR7 chimera bearing the CXCR4 C-terminal constitutively associates with arrestin in the absence of ligands. Our data suggest that the CXCR4 and CXCR7 cores share ligand-binding surfaces for the binding of the synthetic ligands, indicating that CXCR4 inhibitors should be tested also on CXCR7. CXCR4 is a seven-transmembrane domain (7TMR)4 chemokine receptor of considerable clinical interest, involved in stem cell homing to bone marrow niches, cancer biology and metastasis, and HIV infection. Synthetic CXCR4 ligands are being developed, and the CXCR4 blocker AMD3100 has reached the clinic for the mobilization of hematopoietic stem cells from donor bone marrow. The natural CXCR4 ligand, the chemokine CXCL12 (also called SDF-1), has later been found to also bind the atypical chemokine receptor CXCR7, which in addition recognizes the chemokine CXCL11 (also called I-TAC) (1, 2). CXCR7 is atypical in that no classical heterotrimeric G-protein signaling pathways are observed and in that it does not induce chemotaxis of motile cells. However, CXCR7 sets off G-protein-independent signaling via the ␤-arrestin pathway, leading to activation of the Erk 1/2 kinases (3, 4). Functionally, CXCR7 has been implicated in cancer cell growth and transendothelial migration (2, 5, 6). Intriguingly, CXCR7 and CXCR4 can heteromerize, and this attenuates CXCR4 G-protein signaling (7,8). Modulation of CXCR4 has been suggested as a major role of CXCR7 (9).Given that CXCR4 and CXCR7 share a chemokine ligand, we have previously tested the effects of AMD3100 on CXCR7 and found that it induces arrestin recruitment at high doses on this receptor, contrary to its effect on CXCR4 (3). This findin...

show abstract

“…[8] There have been a few reports of optical imaging probes designed to target CXCR4; most involved fluorescently tagged peptides with high binding affinities. [9][10][11] In 2007, Archibald et al reported a small molecule with structural similarities to AMD3100 that also contained a fluorescent rhodamine attachment. [12] Whilst the uncomplexed compound did not inhibit the binding of CXCR4-specific monoclonal antibodies, the corresponding copper complex was shown to have more favourable binding properties.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a Fluorescent Derivative of AMD3100 and its Interaction with the CXCR4 Chemokine Receptor

et al. 2011

View full text Add to dashboard Cite

AMD3100 is a potent and selective antagonist of the CXCR4 receptor; it has been shown to block the route of entry of HIV into host T-cells. This compound and its analogues have since been found to act as haematopoietic stem cell mobilisation agents and, more recently, as anti-cancer agents. Here, we have examined a fluorescent derivative of AMD3100, L(1), which offered the potential to assess the behaviour of AMD3100 at the cell surface by using optical imaging modalities. The binuclear Zn(II) , Cu(II) and Ni(II) complexes of L(1) have also been investigated as these metals have been previously shown to enhance the binding properties of AMD3100. Furthermore, Zn(II) and Cu(II) are known to enhance and quench, respectively, the fluorescence of similar anthracenyl-based ligands. Whilst L(1) demonstrates an ability to inhibit the binding of the anti-CXCR4 monoclonal antibody 12G5 (IC(50) =0.25-0.9 μM), the incorporation of an anthracenyl moiety resulted in a significantly reduced affinity for CXCR4 compared to AMD3100 (IC(50) =10 nM). We observed no significant increase in fluorescence intensity following incubation with murine pre-B cells overexpressing CXCR4 compared to a control cell line. This limits the usefulness of L(1) as a fluorescent imaging probe. Interestingly, the Zn(II) complex, which carries an overall +4 charge, revealed marginally higher specificity and reduced toxicity in vitro compared to the free ligand, albeit with reduced affinity for CXCR4 (IC(50) =1.8-5 μM). We suggest that the incorporation of an anthracenyl group contributes to the lipophilic character of the free ligand, thereby resulting in transport across the plasma membrane. This effect is seemingly diminished when the ligand is complexed to charged metal ions.

show abstract

Synthesis and Application of Fluorescein‐ and Biotin‐Labeled Molecular Probes for the Chemokine Receptor CXCR4

Cited by 37 publications

References 45 publications

Peptide‐Functionalized Luminescent Iridium Complexes for Lifetime Imaging of CXCR4 Expression

Peptide‐Functionalized Luminescent Iridium Complexes for Lifetime Imaging of CXCR4 Expression

The Peptidomimetic CXCR4 Antagonist TC14012 Recruits β-Arrestin to CXCR7

Evaluation of a Fluorescent Derivative of AMD3100 and its Interaction with the CXCR4 Chemokine Receptor

Contact Info

Product

Resources

About