Abstract:

Abstract:Objective
 To study the features of Bifidobacterium breve carrying endostatin（ES）and interferon γ（IFNγ）and its anti-tumor effect   in mice with lung cancer.Methods The target genes ES and IFNγ were transferred into Bifidobacterium breve by plasmids and identified,then the Bifidobacterium breve marked by 3H-TdR were given into lung-cancer-bearing mice by caudal vein injection and by gavage.The experiment included control,Bifidobacterium breve without plasmid (B-b),Bifidobacterium breve with empty plasmid (B-b-pNZ44), Bifidobacterium breve with endostatin (B-b-pNZ44-ssEndostatin),Bifidobacterium breve with IFNγ (B-b- pNZ44- IFNγ) and Bifidobacterium breve conbination (B-b-pNZ44-ssEndostatin + B-b-pNZ44-IFNγ) groups.The distribution of  the Bifidobacterium breve,the changes of tumor size,the activity of splenic cytotoxic T cell (CTL),natural killer cell (NK),tumor necrosis factor-α (TNF-α) secretion activity and intratumoral micro-vessel density(IMVD) were detected.Results The Bifidobacterium breve carrying ES and IFNγ were successfully constructed,and accumulated inside of the tumor.The radioactivities of different organs were significantly decreased from the 3rd day compared with the 1st day(P<0.05);the radioactivities of tumor tissues were significantly increased with the prolongation of time from the 3rd day compared with the 1st day(P<0.05).The administration of Bifidobacterium breve carrying ES and IFNγ surpressed the growth of tumor,enhanced the activities of CTL,NK and the TNFα secretion activity and reduced the IMVD.Conclusion Bifidobacterium breve carrying ES and IFNγ can targetly implant in  tumor and have anti-tumor effect by immune enhancement and vessel growth inhibition.

Key words:  Bifidobacteria breve；endostatin；interferon γ；lung neoplasm ；gene therapy