Potentiating the cellular targeting and anti-tumor activity of Dp44mTviabinding to human serum albumin: two saturable mechanisms of Dp44mT uptake by cells
| Autor: | Namfon Pantarat, Danuta S. Kalinowski, David E. Hibbs, Des R. Richardson, Munikumar Reddy Doddareddy, Jennifer Ong, Darius J.R. Lane, Vera Richardson, Michael L.-H. Huang, Angelica M. Merlot, Ashleigh M. Fordham, Sumit Sahni |
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| Rok vydání: | 2015 |
| Předmět: |
Models
Molecular Thiosemicarbazones Cell Serum albumin Antineoplastic Agents Apoptosis Cell Movement Cell Line Tumor medicine Humans Binding site Receptor Serum Albumin Dp44mT biology Chemistry Albumin Anti-tumor targeting Human serum albumin Hep G2 Cells Molecular biology medicine.anatomical_structure Oncology Biochemistry Cancer cell MCF-7 Cells biology.protein Drug Screening Assays Antitumor Research Paper medicine.drug |
| Zdroj: | Oncotarget |
| ISSN: | 1949-2553 |
| DOI: | 10.18632/oncotarget.3606 |
| Popis: | // Angelica M. Merlot 1 , Sumit Sahni 1 , Darius J.R. Lane 1 , Ashleigh M. Fordham 1 , Namfon Pantarat 1 , David E. Hibbs 2 , Vera Richardson 1 , Munikumar R. Doddareddy 2 , Jennifer A. Ong 2 , Michael L.H. Huang 1 , Des R. Richardson 1,* and Danuta S. Kalinowski 1,* 1 Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney, Sydney, NSW, Australia 2 Faculty of Pharmacy, The University of Sydney, Sydney, NSW, Australia * These authors are contributed equally as senior authors Correspondence to: Des R. Richardson, email: // Danuta S. Kalinowski, email: // Keywords : Albumin, Dp44mT, Anti-tumor targeting, Human serum albumin Received : January 26, 2015 Accepted : February 14, 2015 Published : March 15, 2015 Abstract Di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT) demonstrates potent anti-cancer activity. We previously demonstrated that 14 C-Dp44mT enters and targets cells through a carrier/receptor-mediated uptake process. Despite structural similarity, 2-benzoylpyridine 4-ethyl-3-thiosemicarbazone (Bp4eT) and pyridoxal isonicotinoyl hydrazone (PIH) enter cells via passive diffusion. Considering albumin alters the uptake of many drugs, we examined the effect of human serum albumin (HSA) on the cellular uptake of Dp44mT, Bp4eT and PIH. Chelator-HSA binding studies demonstrated the following order of relative affinity: Bp4eT≈PIH>Dp44mT. Interestingly, HSA decreased Bp4eT and PIH uptake, potentially due to its high affinity for the ligands. In contrast, HSA markedly stimulated Dp44mT uptake by cells, with two saturable uptake mechanisms identified. The first mechanism saturated at 5-10 µM ( B max :1.20±0.04 × 10 7 molecules/cell; K d :33±3 µM) and was consistent with a previously identified Dp44mT receptor/carrier. The second mechanism was of lower affinity, but higher capacity ( B max :2.90±0.12 × 10 7 molecules/cell; K d :65±6 µM), becoming saturated at 100 µM and was only evident in the presence of HSA. This second saturable Dp44mT uptake process was inhibited by excess HSA and had characteristics suggesting it was mediated by a specific binding site. Significantly, the HSA-mediated increase in the targeting of Dp44mT to cancer cells potentiated apoptosis and could be important for enhancing efficacy. |
| Databáze: | OpenAIRE |
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