We previously demonstrated that human chorionic gonadotropin (hCG) induced migration and invasion in human prostate cancer cells. Currently, the main methods for the treatment of prostate cancer are radical prostatectomy, external beam radiation therapy, brachytherapy, systemic androgen deprivation therapy and chemotherapy, etc. C. But the therapeutic efficacy is unsatisfactory. Development of new therapy such as molecular therapy is necessary for treating prostate cancer. CSF3R But the characterization of the molecular mechanisms causing Baicalin manufacture prostate cancer is the basis for establishing a new therapy. If we determine the therapeutic molecular targets that contributed to prostate cancer first, then we can treat patients via targeting those tumor markers to inhibit prostate cancer, further improve the prognosis Baicalin manufacture and lower the mortality. Human chorionic gonadotropins (hCGs) are heterodimeric glycoproteins secreted by trophoblastic cells in normal pregnancy. HCGs have a few isoforms containing intact hCG, hCG, hCG, hyperglycosylated (hCGh), nicked (hCGn) and core fragment of hCG (hCGcf) . HCG is a molecule with independent function. It has been shown that free hCG is a potential tumor marker produced by a variety of tumors C. We previously reported that hCG decreased E-cadherin expression leading to migration and invasion in prostate cancer cells . However, the involved whole mechanisms are not clear. Extracellular signal-regulated kinase1/2 (ERK1/2) activation has been implicated in carcinogenesis and cancer progression. Increased ERK1/2 activity promotes cancer cell proliferation and Baicalin manufacture metastasis in various cancer cell lines C. ERK1/2 blocker, PD98059 resulted in a reduction of cell growth and invasiveness in prostate cancer. In MA-10 Leydig cells, hCG triggered transient ERK1/2 activation via upstream protein kinase A (PKA) . In addition, hCG also induces ERK1/2 phosphorylation in a PKA-independent manner in endometrium and is involved in carcinogenesis , . Besides, there is evidence that matrix metalloproteinases (MMPs) expression was regulated by ERK1/2 in invasive carcinomas. Studies showed that activated ERK1/2 regulated the activity of MMPs leading to extracelluar matrix (ECM) degradation and cell motility C. Many MMPs are considered as essential proteases in the ECM degradation and remodeling . Report showed that hCG stimulated the secretion of MMP-2 and MMP-9 in a dose-dependent manner in cytotrophoblastic cells . Further, hCG upregulated MMP-2 activity and promoted cell motility in SGHPL-5 cell lines . In human prostate cancer, enhanced MMP-2 and MMP-9 activity contributed to tumor invasion and metastasis C. Studies showed that vitamin D and Vitamin D analog ZK191784 downregulated MMPs to inhibit invasion in prostate cancer C. Undoubtedly, MMPs are the important anti-invasion targets. Hence, we propose that hCG might increase ERK1/2 phosphorylation and further upregulate MMPs to promote cell motility. Consequently, here we will investigate hCG-triggered signaling pathways and the linkage between hCG expression and cell motility. Through this study, we hope that we will find new clues in molecular therapy to treat prostate cancer. Figure 1 HCG expression and secretion after the cells were grown for 24 hours. Materials and Methods Materials HCG standards were purchased from Abcam (Hong Kong). The construct pVSneo-hCG containing hCG cDNA was purchased from Stratagene (La Jolla, CA). Restriction enzymes SalI, XhoI, EcoRI, BamHI, HindIII and T4 DNA ligase, competent cells are the products of Invitrogen (Carlsbad, CA). G418 and crystal violet were purchased from Sigma (St. Louis, MO). Human prostate cancer DU145 and PC3 (to be a backup) cells were the products of American Typical Culture Collection (Rockville, MD). Cells were cultured in DMEM medium (Hyclone) supplemented with 10% fetal bovine serum (Invitrogen), 100 units/mL penicillin, and 100 g/mL streptomycin at 37C, 95% air and 5% CO2. Transwell plates with inner inserts or artificial basement membranes were bought from BD Biosciences (Bedford, MA). Anti-hCG.