| Cancer stem-like cells (CSCs) are original cancer cells that are of characteristics associated with normal stem cell, and they are responsible for cancer initiation, recurrence, and metastasis. Thus, successful elimination of CSCs is critical to effective cancer therapy. Liver cancer is one of the leading cancer worldwide, and the incidence of liver cancer has increased by more than 90% in the USA in the past three decades. The 5-year tumor recurrence rate of liver cancer ranges from 40% to 70%, which results from aggressive invasion and high metastasis rates. Recent advances have showed the importance of CSCs in liver cancer. Among these studies, liver CSCs possess tumor-initiating capacity and are more resistant to conventional chemotherapies than liver cancer cells.Salinomycin is an ionophore antibiotic, and has been reported to eliminate CSCs in a variety of cancers, such as breast cancer, pancreatic cancer and liver cancer. Although salinomycin is generally regarded as a CSCs-targeting drug, it also showed significant toxicity towards liver or prostate cancer cells. Thus, salinomycin is a potentially effective drug in treating liver cancer, since it kill both liver CSCs and cancer cells.In the first chapter, we established the HPLC method to determine the SAL contents. The results show that in the range of 7.82～1000 μg·mL-1 SAL, the concentration of SAL had a good correction with the sample peak area (r=0.999). The linear regression equation was A=940.43C+16584. The linearity, presion, recovery, stability were required, so it can be used for the determination of the SAL contents in vitro.In the second chapter, iRGD-SH andDSPE-PEG2000-MAl was synthesized by coupling reaction. The chemical structure of DSPE-PEG2000-iRGD was identified by MALDI-TOF-MS. The particle size, Zeta potential, the mesoporous structure and drug release in vitro were investigated.The priority DSPE-PEG2000-iRGD micelle have higher encapsulation efficiency (96.64%) and smaller particle size (13nm). Furthermore, mM-SAL-iRGD exhibited a biophasic relase pattern at both pH=5.0 and pH=7.4.In the third chapter, the cellular uptake of CFPE loaded DSPE-PEG2000-iRGD was investigated with HepG2 cells (over expressing NRP-1 receptors) to evaluate the NRP-1 receptor specific targeting ability of DSPE-PEG2000-iRGD. Compared with M-SAL micell, the cellular uptake of M-CFPE-iRGD was significantly enhanced in HepG2 cells and HepG2 cancer stern cells. In addition, these two kinds of blank micells showed negligible cytotoxicity to HepG2 cells and HepG2 cancer stern cells. However, M-SAL-iRGD enhanced cytotoxicity to these cells and could inhibit the formation of HepG2 memospheres.In the last chapter, we focused on the liver cancer targeting an antitumor activity in vivo. First, using HepG2 tumor-bearing male nude mice as NRP-1 over expressed liver cancer xeno-graft mode, we evaluate the biodistribution and tumor targeting of DiR loaded DSPE-PEG2000-iRGD using small animal in vivo imaging system. Results showed M-DiR-iRGD was mainly distributed in live and tumor, what’s more M-DiR-iRGD are more likely accumulatmored in tumor than M-DiR indicating M-DiR-iRGD had good tumor targeting ability. Next we evaluated the pharmacokinetics of SAL, M-SAL and M-SAL-iRGD in SD mice. These results showed that such two kinds of micells could increase the circulation time of SAL in blood stream. Compared with M-SAL, M-SAL-iRGD showed longer t1/2 and lower clearance rate. Last, we evaluated the in vivo antitumor activity of SAL, M-SAL and M-SAL-iRGD in HepG2 tumor-bearing male nude mice and the formulation of tumor spheres.M-SAL-iRGD showed the most effective anti tumor activity and could decrease HepG2 tumor spheres efficiency.In conclusion, M-SAL-iRGD have a high tumor accumulation and could inhibit HepG2 cells and formation of tumor mamospheres so that it could inhibit the growth of liver cancer efficiently. |
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