The assessment of the means among groups was performed using ANOVA followed by a post hoc test. p 0. 05 was considered statistically significant. the ratio image of FRET/CFP was made with MetaMorph software. The emission ratio values were normalized to those of the time. We first examined the antitumor activity of CsA against PTENnegative PC 3 cells. CsA attenuated cell development, specially at levels Gossypol ic50 greater than 10 mM, and increased the proportion of G1 phase cells in a period and concentrationdependent manner. G1 arrest and CsA induced growth inhibition was also observed in DU 145 cells, which express functional PTEN. At the molecular level, CsA reduced the levels of the tumor suppressor Rb in PC 3 cells, and reduced the expression levels of cyclin D1, however not cyclin E. We also found that CsA affected the expression levels of cell cycle inhibitors and activators. These results suggest that CsA inhibits cell growth by causing a arrest in prostate cancer cells, which will be regardless of PTEN position. It did not affect cyclin D1 mRNA levels in PC 3 cells, though CsA lowered the protein levels of cyclin D1. Moreover, the proteosome inhibitor MG132 did not rescue the protein levels of cyclin D1 in CsA treated cells. We therefore hypothesized that CsA lowers cyclin D1 expression through regulation of mTORC1 signaling depending on three facts: mTORC1 helps translation initiation by phosphorylating S6 kinase or 4E binding protein 1, mTORC1 increases cyclin D1 Skin infection expression, and inhibition of mTORC1 causes a G1 arrest. We discovered that CsA lowered phospho S6K and 4EBP levels in a time and concentration dependent fashion in PC 3 cells, supporting our hypothesis. The degrees of phospho S6K and 4EBP were also reduced in CsA addressed DU 145 cells. Because mTORC1 suppresses autophagy, if our theory is correct, CsA could be effective at inducing autophagy. CsA mediated inhibition of mTORC1 was more confirmed by our finding that CsA induced autophagy in PC 3 cells. CsA significantly increased how many GFP LC3 puncta and the degrees of LC3 II, which are autophagy prints. Entirely, angiogenesis tumor our studies indicate that CsA induces a arrest by inhibiting mTORC1 signaling in prostate cancer cells. 3. 2. CsA activates Akt signaling by increasing PIP3 levels via EGFR Because Akt activates mTORC1 signaling, we examined whether CsA prevents Akt activity. Unlike our expectations, CsA increased the levels of phospho Akt rather than reduced them in PC 3 cells. Furthermore, CsA increased the degrees of phospho GSK3b and TSC2, which are Akt substrates. GSK3b levels and the improved phospho Akt were also observed in CsA treated DU145 cells. Under the same circumstances, the total expression levels of Akt were not affected by CsA.