Figure 1

Hsp90α is not secreted either through the classic secretory pathway or in an isoform specific fashion. (a) We identified two isoforms of hsp90α in breast cancer cell lines using quantitative real time PCR. Cells were transfected with either control siRNA (non-targeting) or 100 nM siRNA directed against the HSP90AA1-2 isoform. Data from one of the three cell lines tested are represented (A172 and HT1080 not shown). (b) MDA-MB231 cells were treated with BFA or vehicle control for 16 hours and conditioned media was collected, concentrated and subjected to SDS-PAGE followed by a Western blot probed with anti-hsp90α, MMP-2 or β-actin antibody. (c) Conditioned media from cells treated with siRNA directed against the HSP90AA1-2 isoform was collected, concentrated and subjected to SDS-PAGE followed by a Western blot probed with an anti-hsp90α antibody.