Abstract:

BACKGROUND: Polymer vehicle microsphere is a new form of medicine developed rapidly in recent years, which can control drug release, prolong the biological half-life of drugs, lessen side effects, and achieve targeted delivery.
OBJECTIVE: To construct the polymer microsphere encapusulating recombinant adenovirus with human tissue inhibitors of matrix metalloproteinase-1 (TIMP-1) gene, and to discuss its characterization.
METHODS: The microsphere was constructed by biodegradable poly-DL-lactide-poly (PELA) encapsulating rAdTIMP-1, the recombinant adenovirus carrying TIMP-1. The morphous, diameter, virus encapusulating and loading rate, and releasing kinetics of the microsphere were determined in vitro. HepG2 cells were infected with the microsphere, then, the efficiency of infection was checked by fluorescent microscope. The production and expression of TIMP-1 was identified by gelatin zymography and Western blotting analysis, and the proliferation and invasiveness were detected by MTT analysis and Boyden Chamber assay, respectively.
RESULTS AND CONCLUSION: The microsphere encapsulating rAdTIMP-1 was successfully constructed and its diameter, encapsulating rate, and virus loads were 1.965 μm, 60.0%, and 10.5×108/mg, respectively. Almost 60% of the viruses were released within 120 hours, and the total releasing time would last more than 240 hours. The resultant microsphere encapsulating rAdTIMP-1 can efficiently infected HepG2 cells with an efficiency of infection about 90%. As a result, the infected HepG2 cells significantly increased their TIMP-1 enzyme activity and the expression of TIMP-1 was detected by Western blot. And the tumor cells’ proliferative activity and invasive ability were significantly inhibited by the microsphere. The resultant medical microsphere, with high-performance and slow-release, can markedly inhibit the in vitro biological behaviors of HepG2 cells, which may pave the way for application in prospective in vitro experiment and further liver cancer comprehensive therapy.