The Mechanism Of Emodin- Inhibited The Growth Of The Subcutaneously Transplanted Tumor Of Human K562 Cell In Nude Mice

Objective:1. To observe the inhibitory effects of emodin on the growth transplanted K562 cells in BALB/c nude mice2. To explore the mechanism of apoptosis induced by emodinMethods:1.1 The subcutaneously transplanted tumor models of human K562 cell in nude mice were established. Tumor volume was measured; the weights of tumors were recorded. Tumor growth curve was depicted. The tumor inhibition rate was calculated.1.2 Apoptosis transformation of K562 cells induced by emodine was detected by electronic scan microscope and HE staining.1.3 Apoptosis-related protein levels of Bax and Bcl-2 were determined by immunity histochemistry technology and RT-PCR was used to detect the expressions Bax and Bcl-2 mRNA.1.4 RT-PCR was used to detect the expressions Caspase-3 and Caspase-9 mRNA. Expression of procaspase-3 and procaspase-9 protein was determined by Western blotting analysis.1.5 RT-PCR was used to detected the expressions PI3KmRNA,AKT mRNA and FoxO3a mRNA. Expression of PI3K,AKT and FoxO3a protein were determined by Western blotting analysis.Results:1. Emodin significantly inhibited K562 cell tumor growth in nude mice, with a dose-dependent manner. Compared to negative control group, all the emodin treatment groups showed more obvious inhibition ratio (p<0.05). The high concentration emodin group show similar inhibition ratio as the HU treatment group (p>0.05). Apoptosis and necrosis of tumor cells were found in all emodin groups under the light and electron microscope, and the high concentration emodin group had the strongest effect. The tumor cells in HU group were mainly necrosis.2. The results of immunity histochemistry and RT-PCR indicated that the expressions of Bax protein and Bax mRNA were up-regulated by emodin while Bcl-2 protein and Bcl-2 mRNA were down-regulated in k562 cell tumor tissue.3. The results of RT-PCR indicated emodin up-regulated the expression of caspase-3 and caspase-9 mRNA by a dose-dependent manner. Compared with negetive control group, the expression of procaspase-3 and procaspase-9 protein was down-regulated by emodin.4. The results of RT-PCR indicated emodin down-regulated the expression of PI3K mRNA and AKT mRNA, while up-regulated FoxO3a mRNA by a dose-dependent manner. Western blotting analysis showed that the expression of PI3K and AKT protein in xenografted tumor treated with emodin was markedly decreased and FoxO3a was significantly elevated compared with control group.Conclusions:1. Emodin significantly suppresses the growth of K562 cells in nude mice with a dose-dependent manner. This inhibitory effect is achieved by inducing apoptosis.2. The mechianism may be due to regulation of Bax and Bcl-2 expression, and be relative to activation of the caspase-3 and caspase-9 and PI3K-AKT signaling pathway.