Figure 2.

Effects of MT on the tumorigenesis of prostate cancer cells. (A) Soft-agar assay showing reduced tumorigenesis of LNCaP cells treated with MT. (B) Statistical analysis of the colony number from each group in (A). (C) Anti-tumor activity of MT in vivo. Five-week-old male BALB/c nude mice were injected subcutaneously with a phosphate buffer solution suspension containing 108 log-phase LNCaP cells and then treated with MT (40 mg/kg) or vehicle for 5 weeks. Each test and corresponding control lines were injected into five individual mice. (D) The mice were monitored weekly and the tumor volume was measured as an index of the growth rate. Tumor volume was calculated using the equation volume =1/2 (length × width²). The data are presented as mean ± SEM. (E) IHC staining with Ki-67 in vehicle- and MT-treated tumors. MT, melatonin; LNCaP, Lymph Node Carcinoma of the Prostate.