Tyrosine phosphorylation of HSC70 and its interaction with RFC mediates methotrexate resistance in murine L1210 leukemia cells
| Autor: | Senyo Agbenowu, Christopher K. Daniels, Alok Bhushan, Zechary Rios, James C. K. Lai, Peter P. Sheridan, Tuoen Liu, Ratan Singh, Mengxiong Li, Shousong Cao, Shawn E. Bearden |
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| Rok vydání: | 2015 |
| Předmět: |
musculoskeletal diseases
Cancer Research animal structures Genistein macromolecular substances Proximity ligation assay Article Mice Reduced Folate Carrier Protein chemistry.chemical_compound Dihydrofolate reductase Animals heterocyclic compounds Phosphorylation Tyrosine Leukemia L1210 P-glycoprotein Microscopy Confocal biology HSC70 Heat-Shock Proteins Tyrosine phosphorylation Molecular biology Methotrexate Oncology chemistry Drug Resistance Neoplasm embryonic structures biology.protein L1210 cells |
| Zdroj: | Cancer Letters. 357:231-241 |
| ISSN: | 0304-3835 |
| DOI: | 10.1016/j.canlet.2014.11.036 |
| Popis: | We previously identified and characterized a 66–68 kDa membrane-associated, tyrosine phosphorylated protein in murine leukemia L1210 cells as HSC70 which is a methotrexate (MTX)-binding protein. In order to further characterize the functional role of HSC70 in regulating MTX resistance in L1210 cells, we first showed that HSC70 colocalizes and interacts with reduced folate carrier (RFC) in L1210 cells by confocal laser scanning microscopy and Duolink in situ proximity ligation assay. The tyrosine phosphorylation status of HSC70 found in the membrane fraction was different from the parental L1210/0 and cisplatin (CDDP)–MTX cross resistant L1210/DDP cells. In MTX-binding assays, HSC70 from L1210/DDP cells showed less affinity for MTX–agarose beads than that of L1210/0 cells. In addition, genistein (a tyrosine phosphorylation inhibitor) significantly enhanced the resistance of L1210/0 cells to MTX. Moreover, site-directed mutation studies indicated the importance of tyrosine phosphorylation of HSC70 in regulating its binding to MTX. These findings suggest that tyrosine phosphorylation of HSC70 regulates the transportation of MTX into the cells via the HSC70–RFC system and contributes to MTX resistance in L1210 cells. |
| Databáze: | OpenAIRE |
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