[Modified serum-guided immunoblotting for differential proteomic study of prostate cancer]

To search for a new method of screening for molecular targets for androgen-dependent prostate cancer.

We collected tissue samples and paired serum samples from 3 cases of androgen-dependent prostate cancer (ADPC) treated by surgical resection, and included another 3 samples of benign prostatic hyperplasia (BPH) tissue and normal human serum in the control group. The total proteins extracted were separated and transmembrane by two-dimensional gel electrophoresis, followed by hybridization with the sera of the patients with ADPC and those with hormone-independent prostate cancer (HIPC) as the primary antibodies. The differentially expressed proteins were compared by Western blot, analyzed by MALDI-TOF-MS mass spectrography, and verified by RT-PCR and Western blot following bioinformatic identification.

This modified method exhibited a significantly better effect in displaying differentially expressed proteins, by which 12 differentially expressed protein spots were identified, including Beclin1, glutathione S-transferase P (GSTP1-1), ZBTB7, dihydrodiol dehydrogenase 2 (DDH), enolase (ENO1), glucose-dependent insulin-releasing peptide receptor (GIPR), Mn-superoxide dismutase (MnSOD), phosphoglycerate mutase 1 (PGAM1), amino-peptidyl-prolyl cistrons isomerase (PPIA), and phospholipid-PE-binding protein (PEBP). The mRNA and protein expressions of Beclin1 were significantly down-regulated in androgen-dependent prostate cancer tissues.

This modified serum-guided immunoblotting technique has provided a new method for clarifying the molecular mechanisms of the occurrence and progression of HIPC, in which Beclin1-mediated autophagy may play a key role.