RESUMO
Vitamin D binding protein ( VDBP) is a multi-functional plasma globulin which binds to the vitamin D ( VD) in the circulation system and transporting the latter to various effective organs to exert its biological functions .Studies have found that VD and its carrier VDBP are associated with the risk of various cancers such as breast cancer , prostate cancer , and colorectal cancer however , lacking sufficient epidemiological evidences so far .Furthermore , it is still controversial regarding how VD controls and affects cancer progression.In addition, studies have also demonstrated that VDBP derived macrophage-activating factor (GcMAF) is a potent lymphokine in cancer treatment .Nonetheless, the relationship between VDBP and cancer including the VDBP polymorphism, VDBP plasma concentration are still unclear; more studies are needed to further uncover its role in cancer development and progression , thus providing new evidences for cancer diagnosis, treatment, and prognosis.
RESUMO
Objective To investigate the secrection of Polytuftsin, a macrophage activator in Pichia pastoris expression system. Methods The recombinant plasmid encoding polytuftsin was transformed into the yeast by chemical method, and the positive clones were screened and expressed under the induction of methanod. It was observed that the influence of polytuftsin on macrophage in vivo and in vitro. Results It was verified that the recombinant products was confirmed to be our target protein by SDS-PAGE analysis and PCR assay. The expressed product could activate macrophage to secret cytokine and enhance the capacity of macrophages to kill L1210 tumor cells, the maximum killing rate is up to 40 %. In vivo the leukemia therapeutic trial, the time of tumor arise was delayed; the survival time of L1210 tumor-bear mice treated with Polytuftsin was extended, which is about 20 day. Conclusion The recombination protein polytuftsin, which could activate macrophage and has anti-tumor activity.