Biological and Anti-cancer Activity of Binary Toxin from Lysinibacillus sphaericus

Abstract

Binary toxin produced by Lysinibacillus  sphaericus  (Ls) is highly active against mosquito

larvae of important insect vector. The binary toxin shows a homology structure to pore forming-

aerolysin  family, a toxicity  of which has been discovered against several cancer cell lines. To date,

a cytotoxic  data of Bin  toxin is unavailable for mammalian cells including cancer cells. Herein,

the binary  toxin was tested for its biological  activity  on several cell types. Two  components of the

binary toxin, BinA and BinB were produced separately in Escherichia coli host cell. The biological

tests of BinA  and BinB  mixture  revealed  high toxicity  to Culex quinquefasciatus larvae, while no

activity  was detected for a human-hemolysis.  Interestingly,  the binary toxin showed cytotoxicity

towards cancer cells,  melanoma SK-MEL-28  cell (ATCC  HTB-72) and papilloma carcinoma KB

cell (ATCC  CCL-17),  but it was inactive against the normal human cell, fibroblast Hs68 cell. These

findings  promise a possibility  of bacterial  toxin being a candidate for anti-cancer  substance.  In the

future, the anticancer activity of the binary toxin will be investigated in several other cancer cells.