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Felix Kratz - One of the best experts on this subject based on the ideXlab platform.

  • In vitro and in vivo Evaluation of a paclitaxEl conjugatE with thE divalEnt PEptidE E-[c(RGDfK)2] that targEts intEgrin αvβ3
    International Journal of Pharmaceutics, 2009
    Co-Authors: Claudia Ryppa, Hagit Mann-steinberg, Martin L Biniossek, Ronit Satchi-fainaro, Felix Kratz
    Abstract:

    Abstract ThE αvβ3 intEgrin is ovErExprEssEd on prolifErating EndothElial cElls such as thosE prEsEnt in growing tumors as wEll as on tumor cElls of various origins. Tumor-inducEd angiogEnEsis can bE inhibitEd in vivo by antagonizing thE αvβ3 intEgrin with small PEptidEs containing thE arginyl-glycyl-aspartic acid (RGD) amino acid sEquEncE. ThE divalEnt cyclic PEptidE E-[c(RGDfK)2] is a novEl ligand-basEd vascular-targEting agEnt that binds intEgrin αvβ3 and dEmonstratEd high uptakE in OVCAR-3 xEnograft tumors. In this work, wE couplEd thE 2′-OH-group of paclitaxEl through an aliphatic EstEr to thE amino group of E-[c(RGDfK)2] or thE control PEptidE c(RADfK), thus obtaining thE dErivativEs E-[c(RGDfK)2]-paclitaxEl and c(RADfK)-paclitaxEl. SubsEquEntly, wE invEstigatEd thE activity of thE paclitaxEl dErivativEs using sEvEral wEll-EstablishEd in vitro angiogEnEsis assays: using a standard 72 h EndothElial cEll prolifEration assay, wE showEd that both E-[c(RGDfK)2]-paclitaxEl and c(RADfK)-paclitaxEl inhibit thE prolifEration of human umbilical vEin EndothElial cElls (HUVEC) in a similar mannEr as frEE paclitaxEl (IC50 valuE ∼0.4 nM), an obsErvation that can bE ExplainEd by thE half-lifE of thE paclitaxEl EstEr bond in thE conjugatEs of ∼2 h at pH 7. In contrast, a 30-min ExposurE of thE cElls to thE thrEE drugs showEd a clEar diffErEncE bEtwEEn frEE paclitaxEl, E-[c(RGDfK)2]-paclitaxEl and c(RADfK)-paclitaxEl with IC50 valuEs of 10 nM, 25 nM, and 60 nM, rEspEctivEly. ThEsE diffErEncEs arE vEry likEly duE to thE diffErEnt routEs of cEllular Entry of thEsE thrEE molEculEs. WhilE thE hydrophobic paclitaxEl diffusEs rapidly through thE cEll mEmbranE, thE chargEd PEptidE-containing dErivativE E-[c(RGDfK)2]-paclitaxEl binds to thE ovErExprEssEd αvβ3 intEgrin in ordEr to EntEr thE cElls via rEcEptor-mEdiatEd Endocytosis. ThE diffErEncEs bEtwEEn thE dErivativEs wErE furthEr dEmonstratEd using an EndothElial cEll adhEsion assay. Inhibition of cEll attachmEnt was obsErvEd only with thE E-[c(RGDfK)2]-paclitaxEl dErivativE indicating its spEcificity to thE growing EndothElial cElls. FurthErmorE, E-[c(RGDfK)2]-paclitaxEl inhibitEd both EndothElial cElls migration and capillary-likE tubE formation. ThEsE rEsults furthEr dEmonstratE thEir antiangiogEnic propErtiEs. In vivo studiEs in an OVCAR-3 xEnograft modEl dEmonstratEd no antitumor Efficacy for EithEr E-[c(RGDfK)2] or E-[c(RGDfK)2]-paclitaxEl comparEd to modEratE Efficacy for paclitaxEl.

  • In vitro and in vivo Evaluation of a paclitaxEl conjugatE with thE divalEnt PEptidE E-[c(RGDfK)2] that targEts intEgrin alpha v bEta 3.
    International journal of pharmaceutics, 2008
    Co-Authors: Claudia Ryppa, Hagit Mann-steinberg, Martin L Biniossek, Ronit Satchi-fainaro, Felix Kratz
    Abstract:

    ThE alpha(v)bEta(3) intEgrin is ovErExprEssEd on prolifErating EndothElial cElls such as thosE prEsEnt in growing tumors as wEll as on tumor cElls of various origins. Tumor-inducEd angiogEnEsis can bE inhibitEd in vivo by antagonizing thE alpha(v)bEta(3) intEgrin with small PEptidEs containing thE arginyl-glycyl-aspartic acid (RGD) amino acid sEquEncE. ThE divalEnt cyclic PEptidE E-[c(RGDfK)(2)] is a novEl ligand-basEd vascular-targEting agEnt that binds intEgrin alpha(v)bEta(3) and dEmonstratEd high uptakE in OVCAR-3 xEnograft tumors. In this work, wE couplEd thE 2'-OH-group of paclitaxEl through an aliphatic EstEr to thE amino group of E-[c(RGDfK)(2)] or thE control PEptidE c(RADfK), thus obtaining thE dErivativEs E-[c(RGDfK)(2)]-paclitaxEl and c(RADfK)-paclitaxEl. SubsEquEntly, wE invEstigatEd thE activity of thE paclitaxEl dErivativEs using sEvEral wEll-EstablishEd in vitro angiogEnEsis assays: using a standard 72 h EndothElial cEll prolifEration assay, wE showEd that both E-[c(RGDfK)(2)]-paclitaxEl and c(RADfK)-paclitaxEl inhibit thE prolifEration of human umbilical vEin EndothElial cElls (HUVEC) in a similar mannEr as frEE paclitaxEl (IC(50) valuE approximatEly 0.4 nM), an obsErvation that can bE ExplainEd by thE half-lifE of thE paclitaxEl EstEr bond in thE conjugatEs of approximatEly 2h at pH 7. In contrast, a 30-min ExposurE of thE cElls to thE thrEE drugs showEd a clEar diffErEncE bEtwEEn frEE paclitaxEl, E-[c(RGDfK)(2)]-paclitaxEl and c(RADfK)-paclitaxEl with IC(50) valuEs of 10nM, 25 nM, and 60 nM, rEspEctivEly. ThEsE diffErEncEs arE vEry likEly duE to thE diffErEnt routEs of cEllular Entry of thEsE thrEE molEculEs. WhilE thE hydrophobic paclitaxEl diffusEs rapidly through thE cEll mEmbranE, thE chargEd PEptidE-containing dErivativE E-[c(RGDfK)(2)]-paclitaxEl binds to thE ovErExprEssEd alpha(v)bEta(3) intEgrin in ordEr to EntEr thE cElls via rEcEptor-mEdiatEd Endocytosis. ThE diffErEncEs bEtwEEn thE dErivativEs wErE furthEr dEmonstratEd using an EndothElial cEll adhEsion assay. Inhibition of cEll attachmEnt was obsErvEd only with thE E-[c(RGDfK)(2)]-paclitaxEl dErivativE indicating its spEcificity to thE growing EndothElial cElls. FurthErmorE, E-[c(RGDfK)(2)]-paclitaxEl inhibitEd both EndothElial cElls migration and capillary-likE tubE formation. ThEsE rEsults furthEr dEmonstratE thEir antiangiogEnic propErtiEs. In vivo studiEs in an OVCAR-3 xEnograft modEl dEmonstratEd no antitumor Efficacy for EithEr E-[c(RGDfK)(2)] or E-[c(RGDfK)(2)]-paclitaxEl comparEd to modEratE Efficacy for paclitaxEl.

  • In Vitro and in Vivo Evaluation of Doxorubicin ConjugatEs with thE DivalEnt PEptidE E-[c(RGDfK)2] that TargEts IntEgrin αvβ3
    Cancer Research, 2008
    Co-Authors: Claudia Ryppa, Hagit Mann-steinberg, Martin L Biniossek, Ronit Satchi-fainaro, Iduna Fichtner, Holger Weber, Felix Kratz
    Abstract:

    IntEgrins, EspEcially intEgrin αvβ3, arE attractivE rEcEptors for vascular targEting stratEgiEs. REcEntly, a divalEnt RGD pEptidomimEtic, E-[c(RGDfK)2], has bEEn dEscribEd that dEmonstratEs incrEasEd uptakE in human ovarian carcinoma OVCAR-3 xEnograft tumors. InspirEd by thEsE rEsults, wE sEt out to dEvElop doxorubicin conjugatEs with E-[c(RGDfK)2] by binding two diffErEnt malEimidE dErivativEs of doxorubicin to E-[c(RGDfK)2] that was thiolatEd with iminothiolanE. In this way, two watEr-solublE dErivativEs wErE obtainEd, E-[c(RGDfK)2]-DOXO-1 and E-[c(RGDfK)2]-DOXO-2. In E-[c(RGDfK)2]-DOXO-1, doxorubicin was bound to thE PEptidE through a stablE amidE bond, and in E-[c(RGDfK)2]-DOXO-2, a MMP-2/MMP-9 clEavablE octaPEptidE was introducEd bEtwEEn doxorubicin and thE PEptidE. ThE rationalE for a MMP-2/MMP-9-clEavablE linkEr was that MMP-2 and MMP-9 bind to intEgrin αvβ3 and both arE ovErExprEssEd in tumor vasculaturE. In addition, analogous control doxorubicin-containing PEptidEs bEaring c(RADfK) that doEs not...

  • In vitro and in vivo Evaluation of doxorubicin conjugatEs with thE divalEnt PEptidE E-[c(RGDfK)2] that targEts intEgrin alphavbEta3.
    Bioconjugate Chemistry, 2008
    Co-Authors: Claudia Ryppa, Hagit Mann-steinberg, Martin L Biniossek, Ronit Satchi-fainaro, Iduna Fichtner, Holger Weber, Felix Kratz
    Abstract:

    IntEgrins, EspEcially intEgrin alpha vbEta 3, arE attractivE rEcEptors for vascular targEting stratEgiEs. REcEntly, a divalEnt RGD pEptidomimEtic, E-[c(RGDfK) 2], has bEEn dEscribEd that dEmonstratEs incrEasEd uptakE in human ovarian carcinoma OVCAR-3 xEnograft tumors. InspirEd by thEsE rEsults, wE sEt out to dEvElop doxorubicin conjugatEs with E-[c(RGDfK) 2] by binding two diffErEnt malEimidE dErivativEs of doxorubicin to E-[c(RGDfK) 2] that was thiolatEd with iminothiolanE. In this way, two watEr-solublE dErivativEs wErE obtainEd, E-[c(RGDfK) 2]-DOXO-1 and E-[c(RGDfK) 2]-DOXO-2. In E-[c(RGDfK) 2]-DOXO-1, doxorubicin was bound to thE PEptidE through a stablE amidE bond, and in E-[c(RGDfK) 2]-DOXO-2, a MMP-2/MMP-9 clEavablE octaPEptidE was introducEd bEtwEEn doxorubicin and thE PEptidE. ThE rationalE for a MMP-2/MMP-9-clEavablE linkEr was that MMP-2 and MMP-9 bind to intEgrin alpha vbEta 3 and both arE ovErExprEssEd in tumor vasculaturE. In addition, analogous control doxorubicin-containing PEptidEs bEaring c(RADfK) that doEs not bind to intEgrin alpha vbEta 3 wErE synthEsizEd, i.E., c(RADfK)-DOXO-1 and c(RADfK)-DOXO-2. WhErEas E-[c(RGDfK) 2]-DOXO-2 was clEavEd EffEctivEly by MMP-2 and in OVCAR-3 tumor homogEnatEs rElEasing a doxorubicin-tEtraPEptidE or doxorubicin as thE final clEavagE product, no rElEasE of doxorubicin was obsErvEd for E-[c(RGDfK) 2]-DOXO-1. ProlifEration of HUVEC in thE prEsEncE of MMP-2-clEavablE doxorubicin-containing PEptidEs ExhibitEd 6- to 10-fold incrEasEd inhibition comparEd to thE amidE-linkEd doxorubicin-containing PEptidEs. In addition, inhibition of HUVEC sprouting during a 24 h ExposurE was approximatEly 3-fold strongEr for E-[c(RGDfK) 2]-DOXO-2 and 20-fold strongEr for thE rEfErEncE PEptidE conjugatE c(RADfK)-DOXO-2 than for doxorubicin alonE. In vivo studiEs in an OVCAR-3 xEnograft modEl dEmonstratEd no or only modEratE antitumor Efficacy for EithEr E-[c(RGDfK) 2], E-[c(RGDfK) 2]-DOXO-1, E-[c(RGDfK) 2]-DOXO-2, or c(RADfK)-DOXO-2, EvEn at dosEs of 3 x 24 mg/kg doxorubicin EquivalEnts, comparEd to an improvEd antitumor EffEct for doxorubicin at 2 x 8 mg/kg.

G Lindblom - One of the best experts on this subject based on the ideXlab platform.

  • InfluEncE of transmEmbranE PEptidEs on bilayErs of phosphatidylcholinEs with diffErEnt acyl chain lEngths studiEd by solid-statE NMR.
    Biochimica et biophysica acta, 2000
    Co-Authors: T Byström, E Strandberg, F A Kovacs, T A Cross, G Lindblom
    Abstract:

    ThE molEcular oriEntation in a lipid mEmbranE of thE PEptidE fragmEnt VEYAGIALFFVAAVLTLWSMLQYLSAAR (phosphatidylglycErophosphatE synthasE (Pgs) PEptidE E) of an intEgral mEmbranE protEin, Pgs, in EschErichia coli has bEEn invEstigatEd by solid-statE 15N nuclEar magnEtic rEsonancE (NMR) on macroscopically alignEd lipid bilayErs. ThE sEcondary structurE of thE PEptidE in lipid vEsiclEs was dEtErminEd by circular dichroism spEctroscopy. FurthErmorE, thE phasE bEhaviour of thE Pgs PEptidE E/diErucoylphosphatidylcholinE (DEruPC)/watEr systEm was dEtErminEd by (2)H, (31)P and 15N solid-statE NMR spEctroscopy. ThE phasE bEhaviour obtainEd was thEn comparEd to that of thE Pgs PEptidE E solubilisEd in diolEoylphosphatidylcholinE and watEr that was prEviously studiEd by MorEin Et al. [Biophys. J. 73 (1997) 3078-3088]. This was aimEd to answEr thE quEstion whEthEr a diffErEncE in thE lEngth of thE hydrophobic part of this PEptidE and thE hydrophobic thicknEss of thE lipid bilayEr (hydrophobic mismatch) will affEct thE phasE bEhaviour. ThE PEptidE mostly has a transmEmbranE oriEntation and is in an alpha-hElical conformation. An isotropic phasE is formEd in DEruPC with high PEptidE contEnt (PEptidE/lipid molar ratio (p/l) > or =1:15) and high watEr contEnt (> or =50%, w/w) at 35 dEgrEEs C. At 55 and 65 dEgrEEs C an isotropic phasE is inducEd at high watEr contEnt (> or =50%, w/w) at all PEptidE contEnts studiEd (no isotropic phasE forms in thE lipid/watEr systEm undEr thE conditions in this study). At high PEptidE contEnts (p/l> or =1:15) an isotropic phasE forms at 20 and 40% (w/w) of watEr at 55 and 65 dEgrEEs C. A comparison of thE phasE bEhaviour of thE two homologous lipid systEms rEvEals striking similaritiEs, although thE thicknEssEs of thE two lipid bilayErs diffEr by 7 A. This suggEsts that thE rationalisation of thE phasE bEhaviour in tErms of thE hydrophobic mismatch is not applicablE to thEsE systEms. ThE C-tErminus of Pgs PEptidE E is amphiphilic and a considErablE part of thE PEptidE is situatEd outsidE thE hydrophobic part of thE bilayEr, a propErty of thE PEptidE that to a largE ExtEnt will affEct thE lipid/PEptidE phasE bEhaviour.

  • InfluEncE of transmEmbranE PEptidEs on bilayErs of phosphatidylcholinEs with diffErEnt acyl chain lEngths studiEd by solid-statE NMR
    Biochimica et Biophysica Acta (BBA) - Biomembranes, 2000
    Co-Authors: T Byström, E Strandberg, F A Kovacs, T A Cross, G Lindblom
    Abstract:

    AbstractThE molEcular oriEntation in a lipid mEmbranE of thE PEptidE fragmEnt VEYAGIALFFVAAVLTLWSMLQYLSAAR (phosphatidylglycErophosphatE synthasE (Pgs) PEptidE E) of an intEgral mEmbranE protEin, Pgs, in EschErichia coli has bEEn invEstigatEd by solid-statE 15N nuclEar magnEtic rEsonancE (NMR) on macroscopically alignEd lipid bilayErs. ThE sEcondary structurE of thE PEptidE in lipid vEsiclEs was dEtErminEd by circular dichroism spEctroscopy. FurthErmorE, thE phasE bEhaviour of thE Pgs PEptidE E/diErucoylphosphatidylcholinE (DEruPC)/watEr systEm was dEtErminEd by 2H, 31P and 15N solid-statE NMR spEctroscopy. ThE phasE bEhaviour obtainEd was thEn comparEd to that of thE Pgs PEptidE E solubilisEd in diolEoylphosphatidylcholinE and watEr that was prEviously studiEd by MorEin Et al. [Biophys. J. 73 (1997) 3078–3088]. This was aimEd to answEr thE quEstion whEthEr a diffErEncE in thE lEngth of thE hydrophobic part of this PEptidE and thE hydrophobic thicknEss of thE lipid bilayEr (hydrophobic mismatch) will affEct thE phasE bEhaviour. ThE PEptidE mostly has a transmEmbranE oriEntation and is in an α-hElical conformation. An isotropic phasE is formEd in DEruPC with high PEptidE contEnt (PEptidE/lipid molar ratio (p/l) ≥1:15) and high watEr contEnt (≥50%, w/w) at 35°C. At 55 and 65°C an isotropic phasE is inducEd at high watEr contEnt (≥50%, w/w) at all PEptidE contEnts studiEd (no isotropic phasE forms in thE lipid/watEr systEm undEr thE conditions in this study). At high PEptidE contEnts (p/l≥1:15) an isotropic phasE forms at 20 and 40% (w/w) of watEr at 55 and 65°C. A comparison of thE phasE bEhaviour of thE two homologous lipid systEms rEvEals striking similaritiEs, although thE thicknEssEs of thE two lipid bilayErs diffEr by 7 Å. This suggEsts that thE rationalisation of thE phasE bEhaviour in tErms of thE hydrophobic mismatch is not applicablE to thEsE systEms. ThE C-tErminus of Pgs PEptidE E is amphiphilic and a considErablE part of thE PEptidE is situatEd outsidE thE hydrophobic part of thE bilayEr, a propErty of thE PEptidE that to a largE ExtEnt will affEct thE lipid/PEptidE phasE bEhaviour

  • influEncE of mEmbranE spanning alpha hElical PEptidEs on thE phasE bEhavior of thE diolEoylphosphatidylcholinE watEr systEm
    Biophysical Journal, 1997
    Co-Authors: S Morein, E Strandberg, J A Killian, Stefan Persson, G Arvidson, R E Koeppe, G Lindblom
    Abstract:

    ThE EffEct of solubilizEd hydrophobic PEptidEs on thE phasE bEhavior of diolEoylphosphatidylcholinE (DOPC)/watEr systEm was studiEd by 2H- and 31P-NMR spEctroscopy and by x-ray diffraction, and partial phasE diagrams wErE constructEd. ThE utilizEd PEptidEs wErE HCO-AWW(LA)5WWA-NHCH2CH2OH (WALP16), which is an artificial PEptidE dEsignEd to rEsEmblE a transmEmbranE part of a mEmbranE protEin; and VEYAGIALFFVAAVLTLWSMLQYLSAAR (Pgs PEptidE E), a PEptidE that is idEntical to onE of thE putativE transmEmbranE sEgmEnts of thE mEmbranE-associatEd protEin phosphatidylglycErophosphatE synthasE (Pgs) in EschErichia coli. Circular dichroism spEctroscopy suggEsts that both PEptidEs arE mostly alpha-hElical in DOPC vEsiclEs. ThE most striking fEaturEs in thE phasE diagram of thE WALP16/DOPC/watEr systEm arE 1) a singlE lamEllar liquid crystallinE (L alpha) phasE forms only at vEry low PEptidE concEntrations. 2) At low watEr contEnt and abovE a PEptidE/lipid molar ratio of approximatEly 1:75 a rEvErsEd hExagonal liquid crystallinE (H[II]) phasE coExists with an L alpha phasE, whilE in ExcEss watEr this phasE forms at a PEptidE/lipid molar ratio of approximatEly 1:25. 3) At PEptidE/lipid ratios > or =1:6 a singlE H(II) phasE is stablE. Also, thE Pgs PEptidE E strongly affEcts thE phasE bEhavior, and a singlE L alpha phasE is only found at low PEptidE concEntrations (PEptidE/lipid molar ratios

  • INFLUENCE OF MEMBRANE-SPANNING ALPHA -HELICAL PEptidES ON THE PHASE BEHAVIOR OF THE DIOLEOYLPHOSPHATIDYLCHOLINE/WATER SYSTEM
    Biophysical Journal, 1997
    Co-Authors: S Morein, E Strandberg, J A Killian, Stefan Persson, G Arvidson, R E Koeppe, G Lindblom
    Abstract:

    ThE EffEct of solubilizEd hydrophobic PEptidEs on thE phasE bEhavior of diolEoylphosphatidylcholinE (DOPC)/watEr systEm was studiEd by 2H- and 31P-NMR spEctroscopy and by x-ray diffraction, and partial phasE diagrams wErE constructEd. ThE utilizEd PEptidEs wErE HCO-AWW(LA)5WWA-NHCH2CH2OH (WALP16), which is an artificial PEptidE dEsignEd to rEsEmblE a transmEmbranE part of a mEmbranE protEin; and VEYAGIALFFVAAVLTLWSMLQYLSAAR (Pgs PEptidE E), a PEptidE that is idEntical to onE of thE putativE transmEmbranE sEgmEnts of thE mEmbranE-associatEd protEin phosphatidylglycErophosphatE synthasE (Pgs) in EschErichia coli. Circular dichroism spEctroscopy suggEsts that both PEptidEs arE mostly alpha-hElical in DOPC vEsiclEs. ThE most striking fEaturEs in thE phasE diagram of thE WALP16/DOPC/watEr systEm arE 1) a singlE lamEllar liquid crystallinE (L alpha) phasE forms only at vEry low PEptidE concEntrations. 2) At low watEr contEnt and abovE a PEptidE/lipid molar ratio of approximatEly 1:75 a rEvErsEd hExagonal liquid crystallinE (H[II]) phasE coExists with an L alpha phasE, whilE in ExcEss watEr this phasE forms at a PEptidE/lipid molar ratio of approximatEly 1:25. 3) At PEptidE/lipid ratios > or =1:6 a singlE H(II) phasE is stablE. Also, thE Pgs PEptidE E strongly affEcts thE phasE bEhavior, and a singlE L alpha phasE is only found at low PEptidE concEntrations (PEptidE/lipid molar ratios

Claudia Ryppa - One of the best experts on this subject based on the ideXlab platform.

  • In vitro and in vivo Evaluation of a paclitaxEl conjugatE with thE divalEnt PEptidE E-[c(RGDfK)2] that targEts intEgrin αvβ3
    International Journal of Pharmaceutics, 2009
    Co-Authors: Claudia Ryppa, Hagit Mann-steinberg, Martin L Biniossek, Ronit Satchi-fainaro, Felix Kratz
    Abstract:

    Abstract ThE αvβ3 intEgrin is ovErExprEssEd on prolifErating EndothElial cElls such as thosE prEsEnt in growing tumors as wEll as on tumor cElls of various origins. Tumor-inducEd angiogEnEsis can bE inhibitEd in vivo by antagonizing thE αvβ3 intEgrin with small PEptidEs containing thE arginyl-glycyl-aspartic acid (RGD) amino acid sEquEncE. ThE divalEnt cyclic PEptidE E-[c(RGDfK)2] is a novEl ligand-basEd vascular-targEting agEnt that binds intEgrin αvβ3 and dEmonstratEd high uptakE in OVCAR-3 xEnograft tumors. In this work, wE couplEd thE 2′-OH-group of paclitaxEl through an aliphatic EstEr to thE amino group of E-[c(RGDfK)2] or thE control PEptidE c(RADfK), thus obtaining thE dErivativEs E-[c(RGDfK)2]-paclitaxEl and c(RADfK)-paclitaxEl. SubsEquEntly, wE invEstigatEd thE activity of thE paclitaxEl dErivativEs using sEvEral wEll-EstablishEd in vitro angiogEnEsis assays: using a standard 72 h EndothElial cEll prolifEration assay, wE showEd that both E-[c(RGDfK)2]-paclitaxEl and c(RADfK)-paclitaxEl inhibit thE prolifEration of human umbilical vEin EndothElial cElls (HUVEC) in a similar mannEr as frEE paclitaxEl (IC50 valuE ∼0.4 nM), an obsErvation that can bE ExplainEd by thE half-lifE of thE paclitaxEl EstEr bond in thE conjugatEs of ∼2 h at pH 7. In contrast, a 30-min ExposurE of thE cElls to thE thrEE drugs showEd a clEar diffErEncE bEtwEEn frEE paclitaxEl, E-[c(RGDfK)2]-paclitaxEl and c(RADfK)-paclitaxEl with IC50 valuEs of 10 nM, 25 nM, and 60 nM, rEspEctivEly. ThEsE diffErEncEs arE vEry likEly duE to thE diffErEnt routEs of cEllular Entry of thEsE thrEE molEculEs. WhilE thE hydrophobic paclitaxEl diffusEs rapidly through thE cEll mEmbranE, thE chargEd PEptidE-containing dErivativE E-[c(RGDfK)2]-paclitaxEl binds to thE ovErExprEssEd αvβ3 intEgrin in ordEr to EntEr thE cElls via rEcEptor-mEdiatEd Endocytosis. ThE diffErEncEs bEtwEEn thE dErivativEs wErE furthEr dEmonstratEd using an EndothElial cEll adhEsion assay. Inhibition of cEll attachmEnt was obsErvEd only with thE E-[c(RGDfK)2]-paclitaxEl dErivativE indicating its spEcificity to thE growing EndothElial cElls. FurthErmorE, E-[c(RGDfK)2]-paclitaxEl inhibitEd both EndothElial cElls migration and capillary-likE tubE formation. ThEsE rEsults furthEr dEmonstratE thEir antiangiogEnic propErtiEs. In vivo studiEs in an OVCAR-3 xEnograft modEl dEmonstratEd no antitumor Efficacy for EithEr E-[c(RGDfK)2] or E-[c(RGDfK)2]-paclitaxEl comparEd to modEratE Efficacy for paclitaxEl.

  • In vitro and in vivo Evaluation of a paclitaxEl conjugatE with thE divalEnt PEptidE E-[c(RGDfK)2] that targEts intEgrin alpha v bEta 3.
    International journal of pharmaceutics, 2008
    Co-Authors: Claudia Ryppa, Hagit Mann-steinberg, Martin L Biniossek, Ronit Satchi-fainaro, Felix Kratz
    Abstract:

    ThE alpha(v)bEta(3) intEgrin is ovErExprEssEd on prolifErating EndothElial cElls such as thosE prEsEnt in growing tumors as wEll as on tumor cElls of various origins. Tumor-inducEd angiogEnEsis can bE inhibitEd in vivo by antagonizing thE alpha(v)bEta(3) intEgrin with small PEptidEs containing thE arginyl-glycyl-aspartic acid (RGD) amino acid sEquEncE. ThE divalEnt cyclic PEptidE E-[c(RGDfK)(2)] is a novEl ligand-basEd vascular-targEting agEnt that binds intEgrin alpha(v)bEta(3) and dEmonstratEd high uptakE in OVCAR-3 xEnograft tumors. In this work, wE couplEd thE 2'-OH-group of paclitaxEl through an aliphatic EstEr to thE amino group of E-[c(RGDfK)(2)] or thE control PEptidE c(RADfK), thus obtaining thE dErivativEs E-[c(RGDfK)(2)]-paclitaxEl and c(RADfK)-paclitaxEl. SubsEquEntly, wE invEstigatEd thE activity of thE paclitaxEl dErivativEs using sEvEral wEll-EstablishEd in vitro angiogEnEsis assays: using a standard 72 h EndothElial cEll prolifEration assay, wE showEd that both E-[c(RGDfK)(2)]-paclitaxEl and c(RADfK)-paclitaxEl inhibit thE prolifEration of human umbilical vEin EndothElial cElls (HUVEC) in a similar mannEr as frEE paclitaxEl (IC(50) valuE approximatEly 0.4 nM), an obsErvation that can bE ExplainEd by thE half-lifE of thE paclitaxEl EstEr bond in thE conjugatEs of approximatEly 2h at pH 7. In contrast, a 30-min ExposurE of thE cElls to thE thrEE drugs showEd a clEar diffErEncE bEtwEEn frEE paclitaxEl, E-[c(RGDfK)(2)]-paclitaxEl and c(RADfK)-paclitaxEl with IC(50) valuEs of 10nM, 25 nM, and 60 nM, rEspEctivEly. ThEsE diffErEncEs arE vEry likEly duE to thE diffErEnt routEs of cEllular Entry of thEsE thrEE molEculEs. WhilE thE hydrophobic paclitaxEl diffusEs rapidly through thE cEll mEmbranE, thE chargEd PEptidE-containing dErivativE E-[c(RGDfK)(2)]-paclitaxEl binds to thE ovErExprEssEd alpha(v)bEta(3) intEgrin in ordEr to EntEr thE cElls via rEcEptor-mEdiatEd Endocytosis. ThE diffErEncEs bEtwEEn thE dErivativEs wErE furthEr dEmonstratEd using an EndothElial cEll adhEsion assay. Inhibition of cEll attachmEnt was obsErvEd only with thE E-[c(RGDfK)(2)]-paclitaxEl dErivativE indicating its spEcificity to thE growing EndothElial cElls. FurthErmorE, E-[c(RGDfK)(2)]-paclitaxEl inhibitEd both EndothElial cElls migration and capillary-likE tubE formation. ThEsE rEsults furthEr dEmonstratE thEir antiangiogEnic propErtiEs. In vivo studiEs in an OVCAR-3 xEnograft modEl dEmonstratEd no antitumor Efficacy for EithEr E-[c(RGDfK)(2)] or E-[c(RGDfK)(2)]-paclitaxEl comparEd to modEratE Efficacy for paclitaxEl.

  • In Vitro and in Vivo Evaluation of Doxorubicin ConjugatEs with thE DivalEnt PEptidE E-[c(RGDfK)2] that TargEts IntEgrin αvβ3
    Cancer Research, 2008
    Co-Authors: Claudia Ryppa, Hagit Mann-steinberg, Martin L Biniossek, Ronit Satchi-fainaro, Iduna Fichtner, Holger Weber, Felix Kratz
    Abstract:

    IntEgrins, EspEcially intEgrin αvβ3, arE attractivE rEcEptors for vascular targEting stratEgiEs. REcEntly, a divalEnt RGD pEptidomimEtic, E-[c(RGDfK)2], has bEEn dEscribEd that dEmonstratEs incrEasEd uptakE in human ovarian carcinoma OVCAR-3 xEnograft tumors. InspirEd by thEsE rEsults, wE sEt out to dEvElop doxorubicin conjugatEs with E-[c(RGDfK)2] by binding two diffErEnt malEimidE dErivativEs of doxorubicin to E-[c(RGDfK)2] that was thiolatEd with iminothiolanE. In this way, two watEr-solublE dErivativEs wErE obtainEd, E-[c(RGDfK)2]-DOXO-1 and E-[c(RGDfK)2]-DOXO-2. In E-[c(RGDfK)2]-DOXO-1, doxorubicin was bound to thE PEptidE through a stablE amidE bond, and in E-[c(RGDfK)2]-DOXO-2, a MMP-2/MMP-9 clEavablE octaPEptidE was introducEd bEtwEEn doxorubicin and thE PEptidE. ThE rationalE for a MMP-2/MMP-9-clEavablE linkEr was that MMP-2 and MMP-9 bind to intEgrin αvβ3 and both arE ovErExprEssEd in tumor vasculaturE. In addition, analogous control doxorubicin-containing PEptidEs bEaring c(RADfK) that doEs not...

  • In vitro and in vivo Evaluation of doxorubicin conjugatEs with thE divalEnt PEptidE E-[c(RGDfK)2] that targEts intEgrin alphavbEta3.
    Bioconjugate Chemistry, 2008
    Co-Authors: Claudia Ryppa, Hagit Mann-steinberg, Martin L Biniossek, Ronit Satchi-fainaro, Iduna Fichtner, Holger Weber, Felix Kratz
    Abstract:

    IntEgrins, EspEcially intEgrin alpha vbEta 3, arE attractivE rEcEptors for vascular targEting stratEgiEs. REcEntly, a divalEnt RGD pEptidomimEtic, E-[c(RGDfK) 2], has bEEn dEscribEd that dEmonstratEs incrEasEd uptakE in human ovarian carcinoma OVCAR-3 xEnograft tumors. InspirEd by thEsE rEsults, wE sEt out to dEvElop doxorubicin conjugatEs with E-[c(RGDfK) 2] by binding two diffErEnt malEimidE dErivativEs of doxorubicin to E-[c(RGDfK) 2] that was thiolatEd with iminothiolanE. In this way, two watEr-solublE dErivativEs wErE obtainEd, E-[c(RGDfK) 2]-DOXO-1 and E-[c(RGDfK) 2]-DOXO-2. In E-[c(RGDfK) 2]-DOXO-1, doxorubicin was bound to thE PEptidE through a stablE amidE bond, and in E-[c(RGDfK) 2]-DOXO-2, a MMP-2/MMP-9 clEavablE octaPEptidE was introducEd bEtwEEn doxorubicin and thE PEptidE. ThE rationalE for a MMP-2/MMP-9-clEavablE linkEr was that MMP-2 and MMP-9 bind to intEgrin alpha vbEta 3 and both arE ovErExprEssEd in tumor vasculaturE. In addition, analogous control doxorubicin-containing PEptidEs bEaring c(RADfK) that doEs not bind to intEgrin alpha vbEta 3 wErE synthEsizEd, i.E., c(RADfK)-DOXO-1 and c(RADfK)-DOXO-2. WhErEas E-[c(RGDfK) 2]-DOXO-2 was clEavEd EffEctivEly by MMP-2 and in OVCAR-3 tumor homogEnatEs rElEasing a doxorubicin-tEtraPEptidE or doxorubicin as thE final clEavagE product, no rElEasE of doxorubicin was obsErvEd for E-[c(RGDfK) 2]-DOXO-1. ProlifEration of HUVEC in thE prEsEncE of MMP-2-clEavablE doxorubicin-containing PEptidEs ExhibitEd 6- to 10-fold incrEasEd inhibition comparEd to thE amidE-linkEd doxorubicin-containing PEptidEs. In addition, inhibition of HUVEC sprouting during a 24 h ExposurE was approximatEly 3-fold strongEr for E-[c(RGDfK) 2]-DOXO-2 and 20-fold strongEr for thE rEfErEncE PEptidE conjugatE c(RADfK)-DOXO-2 than for doxorubicin alonE. In vivo studiEs in an OVCAR-3 xEnograft modEl dEmonstratEd no or only modEratE antitumor Efficacy for EithEr E-[c(RGDfK) 2], E-[c(RGDfK) 2]-DOXO-1, E-[c(RGDfK) 2]-DOXO-2, or c(RADfK)-DOXO-2, EvEn at dosEs of 3 x 24 mg/kg doxorubicin EquivalEnts, comparEd to an improvEd antitumor EffEct for doxorubicin at 2 x 8 mg/kg.

Martin L Biniossek - One of the best experts on this subject based on the ideXlab platform.

  • In vitro and in vivo Evaluation of a paclitaxEl conjugatE with thE divalEnt PEptidE E-[c(RGDfK)2] that targEts intEgrin αvβ3
    International Journal of Pharmaceutics, 2009
    Co-Authors: Claudia Ryppa, Hagit Mann-steinberg, Martin L Biniossek, Ronit Satchi-fainaro, Felix Kratz
    Abstract:

    Abstract ThE αvβ3 intEgrin is ovErExprEssEd on prolifErating EndothElial cElls such as thosE prEsEnt in growing tumors as wEll as on tumor cElls of various origins. Tumor-inducEd angiogEnEsis can bE inhibitEd in vivo by antagonizing thE αvβ3 intEgrin with small PEptidEs containing thE arginyl-glycyl-aspartic acid (RGD) amino acid sEquEncE. ThE divalEnt cyclic PEptidE E-[c(RGDfK)2] is a novEl ligand-basEd vascular-targEting agEnt that binds intEgrin αvβ3 and dEmonstratEd high uptakE in OVCAR-3 xEnograft tumors. In this work, wE couplEd thE 2′-OH-group of paclitaxEl through an aliphatic EstEr to thE amino group of E-[c(RGDfK)2] or thE control PEptidE c(RADfK), thus obtaining thE dErivativEs E-[c(RGDfK)2]-paclitaxEl and c(RADfK)-paclitaxEl. SubsEquEntly, wE invEstigatEd thE activity of thE paclitaxEl dErivativEs using sEvEral wEll-EstablishEd in vitro angiogEnEsis assays: using a standard 72 h EndothElial cEll prolifEration assay, wE showEd that both E-[c(RGDfK)2]-paclitaxEl and c(RADfK)-paclitaxEl inhibit thE prolifEration of human umbilical vEin EndothElial cElls (HUVEC) in a similar mannEr as frEE paclitaxEl (IC50 valuE ∼0.4 nM), an obsErvation that can bE ExplainEd by thE half-lifE of thE paclitaxEl EstEr bond in thE conjugatEs of ∼2 h at pH 7. In contrast, a 30-min ExposurE of thE cElls to thE thrEE drugs showEd a clEar diffErEncE bEtwEEn frEE paclitaxEl, E-[c(RGDfK)2]-paclitaxEl and c(RADfK)-paclitaxEl with IC50 valuEs of 10 nM, 25 nM, and 60 nM, rEspEctivEly. ThEsE diffErEncEs arE vEry likEly duE to thE diffErEnt routEs of cEllular Entry of thEsE thrEE molEculEs. WhilE thE hydrophobic paclitaxEl diffusEs rapidly through thE cEll mEmbranE, thE chargEd PEptidE-containing dErivativE E-[c(RGDfK)2]-paclitaxEl binds to thE ovErExprEssEd αvβ3 intEgrin in ordEr to EntEr thE cElls via rEcEptor-mEdiatEd Endocytosis. ThE diffErEncEs bEtwEEn thE dErivativEs wErE furthEr dEmonstratEd using an EndothElial cEll adhEsion assay. Inhibition of cEll attachmEnt was obsErvEd only with thE E-[c(RGDfK)2]-paclitaxEl dErivativE indicating its spEcificity to thE growing EndothElial cElls. FurthErmorE, E-[c(RGDfK)2]-paclitaxEl inhibitEd both EndothElial cElls migration and capillary-likE tubE formation. ThEsE rEsults furthEr dEmonstratE thEir antiangiogEnic propErtiEs. In vivo studiEs in an OVCAR-3 xEnograft modEl dEmonstratEd no antitumor Efficacy for EithEr E-[c(RGDfK)2] or E-[c(RGDfK)2]-paclitaxEl comparEd to modEratE Efficacy for paclitaxEl.

  • In vitro and in vivo Evaluation of a paclitaxEl conjugatE with thE divalEnt PEptidE E-[c(RGDfK)2] that targEts intEgrin alpha v bEta 3.
    International journal of pharmaceutics, 2008
    Co-Authors: Claudia Ryppa, Hagit Mann-steinberg, Martin L Biniossek, Ronit Satchi-fainaro, Felix Kratz
    Abstract:

    ThE alpha(v)bEta(3) intEgrin is ovErExprEssEd on prolifErating EndothElial cElls such as thosE prEsEnt in growing tumors as wEll as on tumor cElls of various origins. Tumor-inducEd angiogEnEsis can bE inhibitEd in vivo by antagonizing thE alpha(v)bEta(3) intEgrin with small PEptidEs containing thE arginyl-glycyl-aspartic acid (RGD) amino acid sEquEncE. ThE divalEnt cyclic PEptidE E-[c(RGDfK)(2)] is a novEl ligand-basEd vascular-targEting agEnt that binds intEgrin alpha(v)bEta(3) and dEmonstratEd high uptakE in OVCAR-3 xEnograft tumors. In this work, wE couplEd thE 2'-OH-group of paclitaxEl through an aliphatic EstEr to thE amino group of E-[c(RGDfK)(2)] or thE control PEptidE c(RADfK), thus obtaining thE dErivativEs E-[c(RGDfK)(2)]-paclitaxEl and c(RADfK)-paclitaxEl. SubsEquEntly, wE invEstigatEd thE activity of thE paclitaxEl dErivativEs using sEvEral wEll-EstablishEd in vitro angiogEnEsis assays: using a standard 72 h EndothElial cEll prolifEration assay, wE showEd that both E-[c(RGDfK)(2)]-paclitaxEl and c(RADfK)-paclitaxEl inhibit thE prolifEration of human umbilical vEin EndothElial cElls (HUVEC) in a similar mannEr as frEE paclitaxEl (IC(50) valuE approximatEly 0.4 nM), an obsErvation that can bE ExplainEd by thE half-lifE of thE paclitaxEl EstEr bond in thE conjugatEs of approximatEly 2h at pH 7. In contrast, a 30-min ExposurE of thE cElls to thE thrEE drugs showEd a clEar diffErEncE bEtwEEn frEE paclitaxEl, E-[c(RGDfK)(2)]-paclitaxEl and c(RADfK)-paclitaxEl with IC(50) valuEs of 10nM, 25 nM, and 60 nM, rEspEctivEly. ThEsE diffErEncEs arE vEry likEly duE to thE diffErEnt routEs of cEllular Entry of thEsE thrEE molEculEs. WhilE thE hydrophobic paclitaxEl diffusEs rapidly through thE cEll mEmbranE, thE chargEd PEptidE-containing dErivativE E-[c(RGDfK)(2)]-paclitaxEl binds to thE ovErExprEssEd alpha(v)bEta(3) intEgrin in ordEr to EntEr thE cElls via rEcEptor-mEdiatEd Endocytosis. ThE diffErEncEs bEtwEEn thE dErivativEs wErE furthEr dEmonstratEd using an EndothElial cEll adhEsion assay. Inhibition of cEll attachmEnt was obsErvEd only with thE E-[c(RGDfK)(2)]-paclitaxEl dErivativE indicating its spEcificity to thE growing EndothElial cElls. FurthErmorE, E-[c(RGDfK)(2)]-paclitaxEl inhibitEd both EndothElial cElls migration and capillary-likE tubE formation. ThEsE rEsults furthEr dEmonstratE thEir antiangiogEnic propErtiEs. In vivo studiEs in an OVCAR-3 xEnograft modEl dEmonstratEd no antitumor Efficacy for EithEr E-[c(RGDfK)(2)] or E-[c(RGDfK)(2)]-paclitaxEl comparEd to modEratE Efficacy for paclitaxEl.

  • In Vitro and in Vivo Evaluation of Doxorubicin ConjugatEs with thE DivalEnt PEptidE E-[c(RGDfK)2] that TargEts IntEgrin αvβ3
    Cancer Research, 2008
    Co-Authors: Claudia Ryppa, Hagit Mann-steinberg, Martin L Biniossek, Ronit Satchi-fainaro, Iduna Fichtner, Holger Weber, Felix Kratz
    Abstract:

    IntEgrins, EspEcially intEgrin αvβ3, arE attractivE rEcEptors for vascular targEting stratEgiEs. REcEntly, a divalEnt RGD pEptidomimEtic, E-[c(RGDfK)2], has bEEn dEscribEd that dEmonstratEs incrEasEd uptakE in human ovarian carcinoma OVCAR-3 xEnograft tumors. InspirEd by thEsE rEsults, wE sEt out to dEvElop doxorubicin conjugatEs with E-[c(RGDfK)2] by binding two diffErEnt malEimidE dErivativEs of doxorubicin to E-[c(RGDfK)2] that was thiolatEd with iminothiolanE. In this way, two watEr-solublE dErivativEs wErE obtainEd, E-[c(RGDfK)2]-DOXO-1 and E-[c(RGDfK)2]-DOXO-2. In E-[c(RGDfK)2]-DOXO-1, doxorubicin was bound to thE PEptidE through a stablE amidE bond, and in E-[c(RGDfK)2]-DOXO-2, a MMP-2/MMP-9 clEavablE octaPEptidE was introducEd bEtwEEn doxorubicin and thE PEptidE. ThE rationalE for a MMP-2/MMP-9-clEavablE linkEr was that MMP-2 and MMP-9 bind to intEgrin αvβ3 and both arE ovErExprEssEd in tumor vasculaturE. In addition, analogous control doxorubicin-containing PEptidEs bEaring c(RADfK) that doEs not...

  • In vitro and in vivo Evaluation of doxorubicin conjugatEs with thE divalEnt PEptidE E-[c(RGDfK)2] that targEts intEgrin alphavbEta3.
    Bioconjugate Chemistry, 2008
    Co-Authors: Claudia Ryppa, Hagit Mann-steinberg, Martin L Biniossek, Ronit Satchi-fainaro, Iduna Fichtner, Holger Weber, Felix Kratz
    Abstract:

    IntEgrins, EspEcially intEgrin alpha vbEta 3, arE attractivE rEcEptors for vascular targEting stratEgiEs. REcEntly, a divalEnt RGD pEptidomimEtic, E-[c(RGDfK) 2], has bEEn dEscribEd that dEmonstratEs incrEasEd uptakE in human ovarian carcinoma OVCAR-3 xEnograft tumors. InspirEd by thEsE rEsults, wE sEt out to dEvElop doxorubicin conjugatEs with E-[c(RGDfK) 2] by binding two diffErEnt malEimidE dErivativEs of doxorubicin to E-[c(RGDfK) 2] that was thiolatEd with iminothiolanE. In this way, two watEr-solublE dErivativEs wErE obtainEd, E-[c(RGDfK) 2]-DOXO-1 and E-[c(RGDfK) 2]-DOXO-2. In E-[c(RGDfK) 2]-DOXO-1, doxorubicin was bound to thE PEptidE through a stablE amidE bond, and in E-[c(RGDfK) 2]-DOXO-2, a MMP-2/MMP-9 clEavablE octaPEptidE was introducEd bEtwEEn doxorubicin and thE PEptidE. ThE rationalE for a MMP-2/MMP-9-clEavablE linkEr was that MMP-2 and MMP-9 bind to intEgrin alpha vbEta 3 and both arE ovErExprEssEd in tumor vasculaturE. In addition, analogous control doxorubicin-containing PEptidEs bEaring c(RADfK) that doEs not bind to intEgrin alpha vbEta 3 wErE synthEsizEd, i.E., c(RADfK)-DOXO-1 and c(RADfK)-DOXO-2. WhErEas E-[c(RGDfK) 2]-DOXO-2 was clEavEd EffEctivEly by MMP-2 and in OVCAR-3 tumor homogEnatEs rElEasing a doxorubicin-tEtraPEptidE or doxorubicin as thE final clEavagE product, no rElEasE of doxorubicin was obsErvEd for E-[c(RGDfK) 2]-DOXO-1. ProlifEration of HUVEC in thE prEsEncE of MMP-2-clEavablE doxorubicin-containing PEptidEs ExhibitEd 6- to 10-fold incrEasEd inhibition comparEd to thE amidE-linkEd doxorubicin-containing PEptidEs. In addition, inhibition of HUVEC sprouting during a 24 h ExposurE was approximatEly 3-fold strongEr for E-[c(RGDfK) 2]-DOXO-2 and 20-fold strongEr for thE rEfErEncE PEptidE conjugatE c(RADfK)-DOXO-2 than for doxorubicin alonE. In vivo studiEs in an OVCAR-3 xEnograft modEl dEmonstratEd no or only modEratE antitumor Efficacy for EithEr E-[c(RGDfK) 2], E-[c(RGDfK) 2]-DOXO-1, E-[c(RGDfK) 2]-DOXO-2, or c(RADfK)-DOXO-2, EvEn at dosEs of 3 x 24 mg/kg doxorubicin EquivalEnts, comparEd to an improvEd antitumor EffEct for doxorubicin at 2 x 8 mg/kg.

Ronit Satchi-fainaro - One of the best experts on this subject based on the ideXlab platform.

  • In vitro and in vivo Evaluation of a paclitaxEl conjugatE with thE divalEnt PEptidE E-[c(RGDfK)2] that targEts intEgrin αvβ3
    International Journal of Pharmaceutics, 2009
    Co-Authors: Claudia Ryppa, Hagit Mann-steinberg, Martin L Biniossek, Ronit Satchi-fainaro, Felix Kratz
    Abstract:

    Abstract ThE αvβ3 intEgrin is ovErExprEssEd on prolifErating EndothElial cElls such as thosE prEsEnt in growing tumors as wEll as on tumor cElls of various origins. Tumor-inducEd angiogEnEsis can bE inhibitEd in vivo by antagonizing thE αvβ3 intEgrin with small PEptidEs containing thE arginyl-glycyl-aspartic acid (RGD) amino acid sEquEncE. ThE divalEnt cyclic PEptidE E-[c(RGDfK)2] is a novEl ligand-basEd vascular-targEting agEnt that binds intEgrin αvβ3 and dEmonstratEd high uptakE in OVCAR-3 xEnograft tumors. In this work, wE couplEd thE 2′-OH-group of paclitaxEl through an aliphatic EstEr to thE amino group of E-[c(RGDfK)2] or thE control PEptidE c(RADfK), thus obtaining thE dErivativEs E-[c(RGDfK)2]-paclitaxEl and c(RADfK)-paclitaxEl. SubsEquEntly, wE invEstigatEd thE activity of thE paclitaxEl dErivativEs using sEvEral wEll-EstablishEd in vitro angiogEnEsis assays: using a standard 72 h EndothElial cEll prolifEration assay, wE showEd that both E-[c(RGDfK)2]-paclitaxEl and c(RADfK)-paclitaxEl inhibit thE prolifEration of human umbilical vEin EndothElial cElls (HUVEC) in a similar mannEr as frEE paclitaxEl (IC50 valuE ∼0.4 nM), an obsErvation that can bE ExplainEd by thE half-lifE of thE paclitaxEl EstEr bond in thE conjugatEs of ∼2 h at pH 7. In contrast, a 30-min ExposurE of thE cElls to thE thrEE drugs showEd a clEar diffErEncE bEtwEEn frEE paclitaxEl, E-[c(RGDfK)2]-paclitaxEl and c(RADfK)-paclitaxEl with IC50 valuEs of 10 nM, 25 nM, and 60 nM, rEspEctivEly. ThEsE diffErEncEs arE vEry likEly duE to thE diffErEnt routEs of cEllular Entry of thEsE thrEE molEculEs. WhilE thE hydrophobic paclitaxEl diffusEs rapidly through thE cEll mEmbranE, thE chargEd PEptidE-containing dErivativE E-[c(RGDfK)2]-paclitaxEl binds to thE ovErExprEssEd αvβ3 intEgrin in ordEr to EntEr thE cElls via rEcEptor-mEdiatEd Endocytosis. ThE diffErEncEs bEtwEEn thE dErivativEs wErE furthEr dEmonstratEd using an EndothElial cEll adhEsion assay. Inhibition of cEll attachmEnt was obsErvEd only with thE E-[c(RGDfK)2]-paclitaxEl dErivativE indicating its spEcificity to thE growing EndothElial cElls. FurthErmorE, E-[c(RGDfK)2]-paclitaxEl inhibitEd both EndothElial cElls migration and capillary-likE tubE formation. ThEsE rEsults furthEr dEmonstratE thEir antiangiogEnic propErtiEs. In vivo studiEs in an OVCAR-3 xEnograft modEl dEmonstratEd no antitumor Efficacy for EithEr E-[c(RGDfK)2] or E-[c(RGDfK)2]-paclitaxEl comparEd to modEratE Efficacy for paclitaxEl.

  • In vitro and in vivo Evaluation of a paclitaxEl conjugatE with thE divalEnt PEptidE E-[c(RGDfK)2] that targEts intEgrin alpha v bEta 3.
    International journal of pharmaceutics, 2008
    Co-Authors: Claudia Ryppa, Hagit Mann-steinberg, Martin L Biniossek, Ronit Satchi-fainaro, Felix Kratz
    Abstract:

    ThE alpha(v)bEta(3) intEgrin is ovErExprEssEd on prolifErating EndothElial cElls such as thosE prEsEnt in growing tumors as wEll as on tumor cElls of various origins. Tumor-inducEd angiogEnEsis can bE inhibitEd in vivo by antagonizing thE alpha(v)bEta(3) intEgrin with small PEptidEs containing thE arginyl-glycyl-aspartic acid (RGD) amino acid sEquEncE. ThE divalEnt cyclic PEptidE E-[c(RGDfK)(2)] is a novEl ligand-basEd vascular-targEting agEnt that binds intEgrin alpha(v)bEta(3) and dEmonstratEd high uptakE in OVCAR-3 xEnograft tumors. In this work, wE couplEd thE 2'-OH-group of paclitaxEl through an aliphatic EstEr to thE amino group of E-[c(RGDfK)(2)] or thE control PEptidE c(RADfK), thus obtaining thE dErivativEs E-[c(RGDfK)(2)]-paclitaxEl and c(RADfK)-paclitaxEl. SubsEquEntly, wE invEstigatEd thE activity of thE paclitaxEl dErivativEs using sEvEral wEll-EstablishEd in vitro angiogEnEsis assays: using a standard 72 h EndothElial cEll prolifEration assay, wE showEd that both E-[c(RGDfK)(2)]-paclitaxEl and c(RADfK)-paclitaxEl inhibit thE prolifEration of human umbilical vEin EndothElial cElls (HUVEC) in a similar mannEr as frEE paclitaxEl (IC(50) valuE approximatEly 0.4 nM), an obsErvation that can bE ExplainEd by thE half-lifE of thE paclitaxEl EstEr bond in thE conjugatEs of approximatEly 2h at pH 7. In contrast, a 30-min ExposurE of thE cElls to thE thrEE drugs showEd a clEar diffErEncE bEtwEEn frEE paclitaxEl, E-[c(RGDfK)(2)]-paclitaxEl and c(RADfK)-paclitaxEl with IC(50) valuEs of 10nM, 25 nM, and 60 nM, rEspEctivEly. ThEsE diffErEncEs arE vEry likEly duE to thE diffErEnt routEs of cEllular Entry of thEsE thrEE molEculEs. WhilE thE hydrophobic paclitaxEl diffusEs rapidly through thE cEll mEmbranE, thE chargEd PEptidE-containing dErivativE E-[c(RGDfK)(2)]-paclitaxEl binds to thE ovErExprEssEd alpha(v)bEta(3) intEgrin in ordEr to EntEr thE cElls via rEcEptor-mEdiatEd Endocytosis. ThE diffErEncEs bEtwEEn thE dErivativEs wErE furthEr dEmonstratEd using an EndothElial cEll adhEsion assay. Inhibition of cEll attachmEnt was obsErvEd only with thE E-[c(RGDfK)(2)]-paclitaxEl dErivativE indicating its spEcificity to thE growing EndothElial cElls. FurthErmorE, E-[c(RGDfK)(2)]-paclitaxEl inhibitEd both EndothElial cElls migration and capillary-likE tubE formation. ThEsE rEsults furthEr dEmonstratE thEir antiangiogEnic propErtiEs. In vivo studiEs in an OVCAR-3 xEnograft modEl dEmonstratEd no antitumor Efficacy for EithEr E-[c(RGDfK)(2)] or E-[c(RGDfK)(2)]-paclitaxEl comparEd to modEratE Efficacy for paclitaxEl.

  • In Vitro and in Vivo Evaluation of Doxorubicin ConjugatEs with thE DivalEnt PEptidE E-[c(RGDfK)2] that TargEts IntEgrin αvβ3
    Cancer Research, 2008
    Co-Authors: Claudia Ryppa, Hagit Mann-steinberg, Martin L Biniossek, Ronit Satchi-fainaro, Iduna Fichtner, Holger Weber, Felix Kratz
    Abstract:

    IntEgrins, EspEcially intEgrin αvβ3, arE attractivE rEcEptors for vascular targEting stratEgiEs. REcEntly, a divalEnt RGD pEptidomimEtic, E-[c(RGDfK)2], has bEEn dEscribEd that dEmonstratEs incrEasEd uptakE in human ovarian carcinoma OVCAR-3 xEnograft tumors. InspirEd by thEsE rEsults, wE sEt out to dEvElop doxorubicin conjugatEs with E-[c(RGDfK)2] by binding two diffErEnt malEimidE dErivativEs of doxorubicin to E-[c(RGDfK)2] that was thiolatEd with iminothiolanE. In this way, two watEr-solublE dErivativEs wErE obtainEd, E-[c(RGDfK)2]-DOXO-1 and E-[c(RGDfK)2]-DOXO-2. In E-[c(RGDfK)2]-DOXO-1, doxorubicin was bound to thE PEptidE through a stablE amidE bond, and in E-[c(RGDfK)2]-DOXO-2, a MMP-2/MMP-9 clEavablE octaPEptidE was introducEd bEtwEEn doxorubicin and thE PEptidE. ThE rationalE for a MMP-2/MMP-9-clEavablE linkEr was that MMP-2 and MMP-9 bind to intEgrin αvβ3 and both arE ovErExprEssEd in tumor vasculaturE. In addition, analogous control doxorubicin-containing PEptidEs bEaring c(RADfK) that doEs not...

  • In vitro and in vivo Evaluation of doxorubicin conjugatEs with thE divalEnt PEptidE E-[c(RGDfK)2] that targEts intEgrin alphavbEta3.
    Bioconjugate Chemistry, 2008
    Co-Authors: Claudia Ryppa, Hagit Mann-steinberg, Martin L Biniossek, Ronit Satchi-fainaro, Iduna Fichtner, Holger Weber, Felix Kratz
    Abstract:

    IntEgrins, EspEcially intEgrin alpha vbEta 3, arE attractivE rEcEptors for vascular targEting stratEgiEs. REcEntly, a divalEnt RGD pEptidomimEtic, E-[c(RGDfK) 2], has bEEn dEscribEd that dEmonstratEs incrEasEd uptakE in human ovarian carcinoma OVCAR-3 xEnograft tumors. InspirEd by thEsE rEsults, wE sEt out to dEvElop doxorubicin conjugatEs with E-[c(RGDfK) 2] by binding two diffErEnt malEimidE dErivativEs of doxorubicin to E-[c(RGDfK) 2] that was thiolatEd with iminothiolanE. In this way, two watEr-solublE dErivativEs wErE obtainEd, E-[c(RGDfK) 2]-DOXO-1 and E-[c(RGDfK) 2]-DOXO-2. In E-[c(RGDfK) 2]-DOXO-1, doxorubicin was bound to thE PEptidE through a stablE amidE bond, and in E-[c(RGDfK) 2]-DOXO-2, a MMP-2/MMP-9 clEavablE octaPEptidE was introducEd bEtwEEn doxorubicin and thE PEptidE. ThE rationalE for a MMP-2/MMP-9-clEavablE linkEr was that MMP-2 and MMP-9 bind to intEgrin alpha vbEta 3 and both arE ovErExprEssEd in tumor vasculaturE. In addition, analogous control doxorubicin-containing PEptidEs bEaring c(RADfK) that doEs not bind to intEgrin alpha vbEta 3 wErE synthEsizEd, i.E., c(RADfK)-DOXO-1 and c(RADfK)-DOXO-2. WhErEas E-[c(RGDfK) 2]-DOXO-2 was clEavEd EffEctivEly by MMP-2 and in OVCAR-3 tumor homogEnatEs rElEasing a doxorubicin-tEtraPEptidE or doxorubicin as thE final clEavagE product, no rElEasE of doxorubicin was obsErvEd for E-[c(RGDfK) 2]-DOXO-1. ProlifEration of HUVEC in thE prEsEncE of MMP-2-clEavablE doxorubicin-containing PEptidEs ExhibitEd 6- to 10-fold incrEasEd inhibition comparEd to thE amidE-linkEd doxorubicin-containing PEptidEs. In addition, inhibition of HUVEC sprouting during a 24 h ExposurE was approximatEly 3-fold strongEr for E-[c(RGDfK) 2]-DOXO-2 and 20-fold strongEr for thE rEfErEncE PEptidE conjugatE c(RADfK)-DOXO-2 than for doxorubicin alonE. In vivo studiEs in an OVCAR-3 xEnograft modEl dEmonstratEd no or only modEratE antitumor Efficacy for EithEr E-[c(RGDfK) 2], E-[c(RGDfK) 2]-DOXO-1, E-[c(RGDfK) 2]-DOXO-2, or c(RADfK)-DOXO-2, EvEn at dosEs of 3 x 24 mg/kg doxorubicin EquivalEnts, comparEd to an improvEd antitumor EffEct for doxorubicin at 2 x 8 mg/kg.