Paralemmin-1 is over-expressed in estrogen-receptor positive breast cancers
1 University of Massachusetts, 637 North Pleasant Street, Amherst, MA 01003-9298, USA
2 Pioneer Valley Life Sciences Institute, 3601 Main Street, Springfield, MA 01107, USA
3 Department of Pathology, Baystate Medical Center, Springfield, MA 01199, USA
4 Department of Neuroscience, Uppsala University Biomedical Center, Uppsala S-75124, Sweden
Cancer Cell International 2012, 12:17 doi:10.1186/1475-2867-12-17Published: 10 May 2012
Paralemmin-1 is a phosphoprotein lipid-anchored to the cytoplasmic face of membranes where it functions in membrane dynamics, maintenance of cell shape, and process formation. Expression of paralemmin-1 and its major splice variant (Δ exon 8) as well as the extent of posttranslational modifications are tissue- and development-specific. Paralemmin-1 expression in normal breast and breast cancer tissue has not been described previously.
Paralemmin-1 mRNA and protein expression was evaluated in ten breast cell lines, 26 primary tumors, and 10 reduction mammoplasty (RM) tissues using real time RT-PCR. Paralemmin-1 splice variants were assessed in tumor and RM tissues using a series of primers and RT-PCR. Paralemmin-1 protein expression was examined in cell lines using Western Blots and in 31 ductal carcinomas in situ, 65 infiltrating ductal carcinomas, and 40 RM tissues using immunohistochemistry. Paralemmin-1 mRNA levels were higher in breast cancers than in RM tissue and estrogen receptor (ER)-positive tumors had higher transcript levels than ER-negative tumors. The Δ exon 8 splice variant was detected more frequently in tumor than in RM tissues. Protein expression was consistent with mRNA results showing higher paralemmin-1 expression in ER-positive tumors.
The differential expression of paralemmin-1 in a subset of breast cancers suggests the existence of variation in membrane dynamics that may be exploited to improve diagnosis or provide a therapeutic target.