Chimeric protein toxins for expression by therapeutic bacteria
Bacteria with tumor-targeting capability express, surface displayed, secreted and/or released modified chimeric therapeutic proteins with enhanced therapeutic activity against a neoplastic tissue including solid tumors, lymphomas and leukemias. The bacteria may be attenuated, non-pathogenic, low pathogenic or a probiotic. The chimeric proteins may be protease sensitive and may optionally be further accompanied by co-expression of a secreted protease inhibitor as a separate molecule or as a fusion.
1. A pharmaceutically acceptable composition in a dosage form for administration to a human or an animal, the composition comprising a live Salmonella bacterium, efficacious for antineoplastic treatment of the human or the animal, comprising a genetic construct having a promoter operably linked to coding sequences for a functionally active modified chimeric Pseudomonas ToxA therapeutic molecule with antineoplastic activity comprising in operable linkage a secretion signal, a flexible linker comprising GGGGSGGGGSGGGGS, SEQ ID NO.: 008, a targeting domain, the Pseudomonas ToxA Domain lb, containing at least 2 cysteines available for cysteine bonds, and the Pseudomonas ToxA Domain III, wherein the modified chimeric Pseudomonas ToxA therapeutic molecule with antineoplastic activity is secreted, dependent on the secretion signal, by the live host bacteria wherein the secreted ToxA is functionally active.
2. The pharmaceutically acceptable composition in a dosage form according to claim 1 , comprising between about 10 5 to 10 12 live Salmonella bacterium each containing the genetic construct.
3. The pharmaceutically acceptable composition in a dosage form according to claim 1 , wherein the Pseudomonas ToxA therapeutic molecule comprises an N-terminal fusion.
4. A method for treating neoplastic tumor cells within a living organism, comprising: administering to a human or an animal a pharmaceutically acceptable composition in a dosage form comprising live genetically engineered Salmonella bacterium having a genetic construct having a promoter which is operably linked to the coding sequence for a functionally active modified chimeric Pseudomonas ToxA therapeutic molecule with antineoplastic activity, having in operable linkage a secretion signal, a flexible linker comprising GGGGSGGGGSGGGGS, SEQ ID NO.: 008, a targeting domain, the Pseudomonas ToxA comprising the Pseudomonas ToxA Domain lb containing at least 2 available cysteines for cysteine bonds, and the Pseudomonas ToxA Domain III, wherein the administered modified ToxA protein is expressed in the tumor cells and is secreted by said bacterium and wherein the secreted ToxA is functionally active.
5. The method according to claim 4 , further comprising treating the human or animal with at least one systemic antibiotic to which the live genetically engineered Salmonella bacterium is sensitive.