Abstract
PURPOSE: To understand the mechanisms of multidrug resistance (MDR) in vincristine-resistant human gastric cancer cell line SGC7901/VCR. METHODS: Comparative proteomics involving two-dimensional gel electrophoresis (2-DE) and ESI-Q-TOF Mass Spectrometry (MS) was performed on total proteins extracts from vincristine-resistant SGC7901/VCR and its parental cell line SGC7901. Then the association of heat shock protein 27 (HSP27), one of the highly expressed proteins in SGC7901/VCR, with MDR was analyzed using antisense oligonucleotides (ASOs) inhibition. To further elucidate the biological functions executed by HSP27 in SGC7901/VCR, we investigated a comprehensive interactome map of HSP27 by coimmunoprecipitation (IP) coupled with MS. RESULTS: In this study, HSP27 was identified as a protein showing increased expression in SGC7901/VCR. The suppression of HSP27 expression by HSP27 ASOs could enhance vincristine and adriamycin chemosensitivity in SGC7901/VCR. Identified 25 HSP27-interacting proteins by IP coupled with MS could be classified into eight categories based on their functions: cytoskeleton organization, chaperones, metabolic enzymes, proteins relative to signal transduction, ribosomal proteins, DNA repair proteins, proteins involved in transcription and translation, and RNA processing, which correspond to the reported functions of HSP27 with MDR. CONCLUSION: These data clearly link HSP27 and multidrug resistance mechanisms in gastric cancer.