ENHANCED HEPATOCYTE GROWTH-FACTOR LEVEL IN HUMAN PROSTATE-CANCER TREATED WITH ENDOCRINE THERAPY

Hepatocyte growth factor (HGF) has been revealed to have various funct ions such as regeneration, cancer invasion and tumor suppression in no rmal and cancer cells of different organs. To compare HGF expression i n non-malignant prostate tissues and prostate cancers pretreated with or without neoadjuvant endocrine therapy (pretreated PC and nontreated PC), the amounts of HGF protein and mRNA were quantitated by Western blot analysis and reverse transcription-competitive polymerase chain r eaction, The biologically active HGF (baHGF), which was converted by a n HGF activator protein from secretory type proHGF, showed significant ly higher expression in pretreated PC than in nontreated PC. The amoun ts of baHGF in pretreated PC were similar to those in non-malignant pr ostate tissues. There was no difference in the expression level of ful l-length HGF mRNA encoding secretory type HGF among the three groups. No variance of tissue content of short variant HGF mRNA encoding a com petitive HGF antagonist among the three groups indicated that short va riant HGF protein in prostate cancer seemed not to function similarly to a competitive HGF antagonist in benign prostate tissues. These resu lts suggest that the tissue level of baHGF in non-treated and pretreat ed PC depends on activation of proHGF supplied from distal organs rath er than de novo HGF mRNA synthesis in prostate glands. Increased baHGF in pretreated PC is expected to relate to tumor suppression in vivo.