Compositions and methods for treatment of cancer using bacteria
Provided herein are compositions comprising substantially non-viable Gram-negative bacterial organisms that have a substantial reduction in endotoxin activity and/or pyrogenicity and methods for treating a cancer using the same. Also provided are methods for treating cancer provided herein, comprising administering to a mammal diagnosed with cancer, substantially non-viable Gram-negative bacteria having a substantial reduction in endotoxin activity and/or pyrogenicity, in an amount sufficient to inhibit growth or metastasis of the cancer. An additional method is provided comprising administering viable or non-viable Gram-negative bacterial organisms that have a genetic defect that results in a substantial loss of lipopolysaccharide within the outer membrane of the bacteria. Further provided are methods for reducing endotoxin activity and/or pyrogenicity in Gram-negative bacteria comprising treatment with polymyxin and glutaraldehyde.
1. A method of killing Gram-negative bacterial cells and reducing lipopolysaccharide (LPS)-mediated endotoxin activity of the Gram-negative bacterial cells while keeping the bacterial cells intact, the method comprising treating live Gram-negative bacterial cells with a polymyxin and with glutaraldehyde under conditions to maintain the integrity of the Gram-negative bacterial cells and to reduce at least 80% of the LPS-mediated endotoxin activity of the Gram-negative bacterial cells compared to the corresponding untreated Gram-negative bacterial cells, wherein the polymyxin is polymyxin B or polymyxin E.
2. The method of claim 1 wherein the live Gram-negative bacterial cells are treated with 200 to 5000 micrograms of the polymyxin per 1×10 7 to 5×10 10 of the live Gram-negative bacterial cells per mL.
3. The method of claim 1 wherein the glutaraldehyde is at a concentration of from 0.5% to 2.0%.
4. The method of claim 3 wherein the glutaraldehyde is at a concentration of from 0.5% to 1.0%.
5. The method of claim 1 wherein the treatment with polymyxin occurs at a temperature of 2 degree C. to 10 degree C.
6. The method of claim 5 wherein the treatment with polymyxin occurs at a temperature of 4 degree C.
7. The method of claim 1 wherein the polymyxin is polymyxin B.
8. The method of claim 7 wherein the polymyxin B is present in the presence of magnesium chloride.
9. The method of claim 8 wherein the magnesium chloride is present at a concentration of 0.5 mM to 30 mM.
10. The method of claim 1 wherein the Gram-negative bacterial cells are Salmonella or Escherichia cells.