ABS ePoster Library

Introduction: Death associated protein 3 (DAP3) is a relatively novel proapoptotic and antioncogenic protein. HSP90 is a heat shock protein identified as a chaperone protein. We investigated the interaction between HSP90 and DAP3 in breast cancer cell lines and the clinical significance of HSP90.
Methods: Conventional PCR was used to screen DAP3 and HSP90 expression in 8 breast cancer cell lines. To explore potential DAP3 interacting partners, paired normal and cancerous breast tissues were immunoprecipitated with a DAP3 antibody before being probed on a protein microarray and further confirmed using Western Blot co-immunoprecipitation in MCF7 cells. Expression of HSP90a and HSP90b in a breast cancer cohort (n=143) was explored with regards to incidence of local recurrence and metastasis.
Results: Conventional PCR demonstrated a similar expression pattern of DAP3 and HSP90 in breast cancer cell lines (n=8). Protein microarray (Kinexus) analysis, following DAP3 immunoprecipitation highlighted an interaction between DAP3 and HSP90. Western Blot co-immunoprecipitation in MCF7 cells similarly highlighted this interaction. Low expression of HSP90 in breast cancer tissue was linked to local recurrence and metastasis.
Conclusions: HSP90 and DAP3 seem to have similar expression patterns across a range of breast cancer cell lines and in our clinical cohort lower expression levels suggest an association with metastasis and local recurrence. Current data implies that there may be a link between HSP90 and DAP3 and this may have functional significance in breast cancer progression.