Prostate cancer (CaP) patients with disseminated disease often suffer from severe
cachexia, which contributes to mortality in advanced
cancer. Human
cachexia-associated
protein (HCAP) was recently identified from a
breast cancer library based on the available 20-amino
acid sequence of proteolysis-inducing factor (PIF), which is a highly active cachectic factor isolated from mouse
colon adenocarcinoma MAC16. Herein, we investigated the expression of HCAP in CaP and its potential involvement in CaP-associated
cachexia. HCAP
mRNA was detected in CaP cell lines, in primary CaP tissues and in its osseous
metastases. In situ hybridization showed HCAP
mRNA to be localized only in the epithelial cells in CaP tissues, in the metastatic foci in bone, liver and lymph node, but not in the stromal cells or in normal prostate tissues. HCAP
protein was detected in 9 of 14 CaP
metastases but not in normal prostate tissues from cadaveric donors or patients with organ-confined
tumors. Our Western blot analysis revealed that HCAP was present in 9 of 19 urine specimens from cachectic CaP patients but not in 19 urine samples of noncachectic patients. HCAP
mRNA and
protein were also detected in LuCaP 35 and PC-3M xenografts from our cachectic animal models. Our results demonstrated that
human CaP cells express HCAP and the expression of HCAP is associated with the progression of CaP and the development of CaP
cachexia.