Human METCAM/MUC18 is a New Diagnostic Marker of and a Driver for Promoting and its Specific SiRNAs, Derived Oligopeptides and Antibodies be used for Decreasing the Malignant Progression of Prostate Cancer

METCAM/MUC18, an integral membrane cell adhesion molecule (CAM) in the Ig-like gene super family, is not expressed in most normal prostate gland, or in all BPH, but overly expressed in most malignant prostate cancer. Its overexpression also correlates with the malignant progression of mouse prostatic adenocarcinoma in a TRAMP model, suggesting that it may be a diagnostic marker for malignant prostate cancer. To demonstrate this, three immunological methods are developed to show promises to use METCAM/MUC18 as a diagnostic marker for the presence of clinical prostate cancer. Enforced expression of METCAM/ MUC18 in a human prostate cancer cell line, LNCaP, promotes tumorigenesis and initiates metastasis to multiple organs in a male nude mouse model, suggesting that it can promote the malignant progression of prostate cancer. ShRNAs in a lentivirus vector could decrease the tumorigenesis of another human prostate cancer cell line, DU145, in a male athymic nude mouse model. Taken together, METCAM/MUC18 is a new diagnostic marker of and a driver for promoting the malignant progression of and its specific siRNAs, oligo-peptides, and antibodies may be used for therapeutic treatments of clinical prostate cancer.