BACKGROUND: Cholecystokinin receptor subtype 2 (CCK-2) is overexpressed in various tumours like medullary thyroid carcinomas and small cell lung cancer. Radiolabelled peptides that bind with high affinity and specificity to CCK-2 receptors, thus hold great potential for visualizing such tumours. METHODS: We compared four 111In labelled gastrin analogues, called minigastrins (MG), namely MG11, MG45, MG47 and MG48 linked to metal chelating DOTA in preclinical experiments. The radiolabelled peptides were tested for peptide binding in CCK-2 receptor-bearing cell line AR42J and for their pharmacokinetics in normal rats. RESULTS: The experiments suggest that all gastrin analogues had similar and relatively rapid internalization into AR42J cells. Binding to CCK-2 receptors in AR42J cells was saturable for all agents but there were some differences in receptor affinity. This biodistribution study in rats showed a rapid decrease in blood radioactivity, predominantly renal clearance and saturable uptake of the radiopharmaceutical and/or its metabolites in the CCK-2 receptor-positive stomach. Higher kidney accumulation of radioactivity was only found for 111In-DOTA-minigastrin 48. CONCLUSIONS: The data suggest that the 111In-DOTA-minigastrin analogues studied are promising candidates for the scintigraphy of CCK-2 receptor-expressing tumours; 111In-DOTA-MG47 and 111In-DOTA-MG11 are the most promising.

• MeSH
• gastriny farmakokinetika   farmakologie   MeSH
• heterocyklické sloučeniny monocyklické MeSH
• komplexní sloučeniny MeSH
• krysa rodu rattus MeSH
• nádorové buněčné linie MeSH
• peptidy MeSH
• radiofarmaka MeSH
• receptor cholecystokininu B metabolismus   MeSH
• tkáňová distribuce MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Cell lines are common model systems in the development of therapeutic proteins and in the research on cellular functions and dysfunctions. In this field, the protein interaction assay is a frequently used tool for assessing the adequacy of a protein for diagnostic and therapeutic purposes. In this study, we investigated the extent to which the interaction characteristics depend on the choice of cell line for HER-family receptors. The interaction characteristics of two therapeutic antibodies (trastuzumab and cetuximab) and one Affibody molecule (ZHER2:342), interacting with the intended receptor were characterized with high precision using an automated real-time interaction method, in different cell lines (HaCaT, A431, HEP-G2, SKOV3, PC3, DU-145). Clear differences in binding affinity and kinetics, up to one order of magnitude, were found for the interaction of the same protein binding to the same receptor on different cells for all three proteins. For HER-family receptors, it is therefore important to refer to the measured affinity for a protein-receptor interaction together with the hosting cell line. The ability to accurately measure affinity and kinetics of a protein-receptor interaction on cell lines of different origins may increase the understanding of underlying receptor biology, and impact the selection of candidates in the development of therapeutic or diagnostic agents.

• MeSH
• afinita protilátek MeSH
• buňky Hep G2 MeSH
• erbB receptory metabolismus   MeSH
• humanizované monoklonální protilátky metabolismus   MeSH
• interakční proteinové domény a motivy MeSH
• kinetika MeSH
• lidé MeSH
• mapování interakce mezi proteiny MeSH
• monoklonální protilátky metabolismus   MeSH
• radioizotopy jodu MeSH
• radioligandová zkouška MeSH
• receptor erbB-2 metabolismus   MeSH
• rekombinantní fúzní proteiny metabolismus   MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

• MeSH
• biomedicínský výzkum MeSH
• diagnostické techniky radioisotopové využití   MeSH
• Didelphis MeSH
• financování organizované MeSH
• gastriny diagnostické užití   terapeutické užití   MeSH
• izotopové značení metody   využití   MeSH
• krysa rodu rattus MeSH
• kultivované buňky MeSH
• lidé MeSH
• lutecium diagnostické užití   terapeutické užití   MeSH
• nádorové buněčné linie enzymologie   chemie   metabolismus   MeSH
• pankreas exokrinní cytologie   enzymologie   MeSH
• proximální tubuly ledvin cytologie   enzymologie   MeSH
• radioizotopy india diagnostické užití   terapeutické užití   MeSH
• receptor cholecystokininu B terapeutické užití   MeSH
• spektrometrie gama metody   využití   MeSH
• statistika jako téma MeSH
• technecium diagnostické užití   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• zvířata MeSH

• MeSH
• financování organizované MeSH
• krysa rodu rattus MeSH
• ledviny účinky léků   MeSH
• oktreotid analogy a deriváty   diagnostické užití   MeSH
• organokovové sloučeniny diagnostické užití   MeSH
• permeabilita buněčné membrány účinky léků   MeSH
• radiofarmaka diagnostické užití   MeSH
• radioterapie metody   využití   MeSH
• receptory somatostatinu metabolismus   účinky léků   MeSH
• separace buněk využití   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• abstrakty MeSH

• MeSH
• buněčné kultury metody   využití   MeSH
• financování organizované MeSH
• krysa rodu rattus MeSH
• nádorové buněčné linie účinky léků   MeSH
• nádory slinivky břišní MeSH
• oktreotid analogy a deriváty   farmakologie   MeSH
• receptory somatostatinu účinky léků   MeSH
• somatostatin analogy a deriváty   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• abstrakty MeSH

OBJECTIVE: Radiolabeled receptor-specific somatostatin analogs labeled with gamma- or beta-emitting radionuclides are useful for scintigraphic imaging and/or therapy of selected neuroendocrine tumors. However, significant renal uptake may result in radiotoxicological injury of the kidney and can limit clinical application of the agents. The aim of the study was to analyze renal handling, rate, and mechanism of renal accumulation of two somatostatin receptor-targeted peptides, [DOTA(0), Tyr(3), Thr(8)]-octreotide (DOTA-TATE) and [DOTA(0), 1-Nal(3)]-octreotide (DOTA-NOC), labeled with indium-111 using in vitro methods. METHODS: The perfused rat kidney and freshly isolated rat renal cells were used as experimental models. The perfusion was performed in a recirculation regimen at constant pressure with solution containing bovine albumin, erythrocytes, and a mixture of essential substrates. The renal cells were isolated from rat kidneys using two-phase collagenase perfusion. Accumulation studies were used to evaluate the renal uptake of the peptides and to compare their accumulation with that of passively or actively transported model drugs. The influence of selected inhibitors of receptor-mediated endocytosis and the inhibition of energy-dependent transport processes on the uptake were also investigated using isolated renal cells. RESULTS: The renal clearance of (111)In-DOTA-NOC in the perfused rat kidney was significantly lower than that of (111)In-DOTA-TATE. Reverse situation was found in the case of renal retention. Pretreatment of the perfused kidney with maleate markedly decreased the renal retention. (111)In-DOTA-NOC was accumulated in the isolated renal cells at a higher rate than (111)In-DOTA-TATE (ratio 3: 1). The uptake of the radiopeptides in renal cells was higher than the uptake of not only the passively transported sucrose but also actively transported and accumulated methylglucose. The rank order of potency to inhibit the uptake by active endocytosis was approximately aprotinin > maleate > lysine. The uptake of the radiopeptides in the renal cells was temperature dependent. CONCLUSIONS: Both in vitro methods showed a higher renal accumulation of (111)In-DOTA-NOC in comparison with (111)In-DOTA-TATE. The renal uptake was partly decreased by inhibitors of receptor-mediated endocytosis and by a block of energy-dependent processes. A significant participation of active transport processes in renal accumulation of the studied peptides was confirmed.

• MeSH
• krysa rodu rattus MeSH
• kultivované buňky MeSH
• ledviny metabolismus   MeSH
• metabolická clearance MeSH
• oktreotid analogy a deriváty   diagnostické užití   farmakokinetika   MeSH
• organokovové sloučeniny diagnostické užití   farmakokinetika   MeSH
• potkani Wistar MeSH
• radiofarmaka diagnostické užití   farmakokinetika   MeSH
• receptory somatostatinu metabolismus   MeSH
• reprodukovatelnost výsledků MeSH
• senzitivita a specificita MeSH
• tkáňová distribuce MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH
• srovnávací studie MeSH

BACKGROUND: In this study, some important biological characteristics of two radiolabelled somatostatin analogues 111In-DOTA-1-Nal3-octreotide (DOTA-NOC) and 111In-DOTA-Tyr3-octreotate (DOTA-TATE) were compared. MATERIALS AND METHODS: Rats were used for in vivo biodistribution experiments and in vitro cell models (OK and AR42J cell lines) were used for simulating the internalization in the kidney and in subtype 2 somatostatin receptor (SSTR2)-positive tissues, respectively. RESULTS: Significantly higher radioactivity concentrations in rat organs with high density of somatostatin receptors after 111In-DOTA-NOC administration in comparison with 111In-DOTA-TATE were observed. The predominant urine excretion was associated with accumulation of the radioactivity in the kidney, where higher retention of 111In-DOTA-TATE compared to 111In-DOTA-NOC was detected. In the OK cell line the opposite results were found. No significant differences in the in vitro internalization and externalization of radioactivity to AR42J cell line were found for either peptide suggesting their same affinity for SSTR2. CONCLUSION: Preclinical experiments indicated that 111In-DOTA-NOC is a very promising peptide for somatostatin receptor-positive tumour visualization. The conflict between the in vitro and in vivo kidney handling showed that the transfer of results from in vitro to in vivo conditions and their interpretation should be performed very carefully because both types of experiments can be affected by different factors, making their simple comparison difficult.

• MeSH
• buněčné linie MeSH
• financování organizované MeSH
• krysa rodu rattus MeSH
• ledvinové kanálky metabolismus   MeSH
• nádorové buněčné linie MeSH
• nádory slinivky břišní metabolismus   MeSH
• oktreotid analogy a deriváty   farmakokinetika   chemie   MeSH
• organokovové sloučeniny farmakokinetika   chemie   MeSH
• potkani Wistar MeSH
• radiofarmaka farmakokinetika   MeSH
• radioizotopy india MeSH
• receptory somatostatinu metabolismus   MeSH
• tkáňová distribuce MeSH
• vačicovití MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• srovnávací studie MeSH

• Publikační typ
• abstrakt z konference MeSH

• MeSH
• játra metabolismus   MeSH
• krysa rodu rattus MeSH
• perfuze MeSH
• radioaktivní indikátory farmakokinetika   chemie   MeSH
• sloučeniny technecia farmakokinetika   chemie   MeSH
• sulfobromoftalein farmakokinetika   MeSH
• žluč chemie   sekrece   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• srovnávací studie MeSH