Our aim is the identification and correlation of changes in
tumor-associated
protein expression which results from
therapy. LNCaP
tumors, excised from nude mice treated either by
orchiectomy or with the chemotherapeutic agent
paclitaxel, were evaluated for the expression of
proteins and receptors associated with growth, differentiation, and angiogenesis using immunohistologic procedures. Compared to untreated control
tumors, both treatments reduced the expression of
vascular endothelial growth factor (
VEGF), prostate-specific membrane
antigen (PSMA),
prostate-specific antigen (PSA),
androgen receptor (AR), and
epidermal growth factor receptor (EGFR). The effect of
paclitaxel treatment on AR expression was the most significant (P = .005). Of particular interest was identifying a significant correlation (P < .000801) between PSMA and
VEGF expression regardless of treatment modality. These altered expressions suggest that PSMA may also be a marker for angiogenesis and could represent a target for deliverable agents recognizing either prostatic
tumors or endothelial development. Cell surface PSMA would then present a unique target for treatment of patients early in their development of prostatic
metastases.