Application of genetically genineered bacterium of attenuated salmonella typhimurium in preparation of medicine for treatment of liver cancer

Abstract

Provided is an application of a genetically engineered bacterium of attenuated Salmonella typhimurium in preparation of medicines for treating liver cancer. The bacterium is attenuated Salmonella typhimurium VNP20009 carrying a plasmid cloned with a methioninase gene. Also provided is a construction method of the bacterium.

1 . A method for treating liver cancer, the method comprising administering a genetically engineered bacterium to a human having liver cancer, wherein the genetically engineered bacterium is attenuated  Salmonella typhimurium  VNP20009 carrying a plasmid, and the plasmid is cloned with a L-methioninase gene. 
     
     
         2 . The method according to  claim 1 , wherein the plasmid is a pSVSPORT plasmid, a pTrc99A plasmid, a pcDNA3.1 plasmid, a pBR322 plasmid or a pET23a plasmid. 
     
     
         3 . The method according to  claim 1 , wherein the genetically engineered bacterium is constructed by: subcloning the L-methioninase gene into the plasmid, then electro-transforming the plasmid to attenuated  Salmonella typhimurium  VNP20009. 
     
     
         4 . The method according to  claim 3 , wherein the electrotransformation condition is as follows: voltage 2400V, resistance 400 Ω, capacitance 25 μF, discharge time 4 ms. 
     
     
         5 . The method according to  claim 3 , wherein the plasmid is pSVSPORT plasmid and the L-methioninase gene is cloned to the plasmid by Kpn I and Hind III restriction sites, then electro-transforming the plasmid to attenuated  Salmonella typhimurium  VNP20009. 
     
     
         6 . The method according to  claim 1 , wherein the the genetically engineered bacterium is administered via intravenous or interventional injection.