Cytolethal distending toxin subunit B conjugated or fused to Bacillus anthracis toxin lethal factor
Inventors
Bachran, Christopher H. • Leppla, Stephen H.
Assignees
US Department of Health and Human Services
Publication Number
US-9890369-B2
Publication Date
2018-02-13
Expiration Date
2034-06-19
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Abstract
Disclosed is a protein comprising a cytolethal distending toxin subunit B (CdtB) conjugated or fused to a Bacillus anthracis toxin lethal factor (LF) or a functional portion of LF. Related chimeric molecules, as well as related nucleic acids, recombinant expression vectors, host cells, populations of cells, pharmaceutical compositions, methods of treating or preventing cancer, and methods of inhibiting the growth of a target cell are also disclosed.
Core Innovation
The invention discloses a protein comprising a cytolethal distending toxin subunit B (CdtB) conjugated or fused to a Bacillus anthracis toxin lethal factor (LF) or a functional portion of LF. This protein exhibits an improved ability to transit to the interior of target cells, facilitating the delivery of CdtB and enhancing its cytotoxic effects. The invention also includes related chimeric molecules, nucleic acids, recombinant expression vectors, host cells, populations of cells, pharmaceutical compositions, and methods of treating or preventing conditions such as cancer or inhibiting the growth of target cells.
Cytolethal distending toxin (Cdt) is a bacterial toxin with cytotoxic activity that may be useful for destroying or inhibiting growth of undesirable cells like cancer cells. However, the effective use of Cdt is hindered by inefficient delivery of Cdt to the interior of cells, reducing its cytotoxic effects. The invention addresses this problem by conjugating or fusing CdtB to Bacillus anthracis toxin lethal factor (LF), leveraging LF's ability to facilitate delivery into cells via protective antigen (PA)-mediated translocation, thus improving intracellular delivery and efficacy.
Claims Coverage
The patent covers seven main inventive features disclosed in independent claims relating to a protein, chimeric molecules, nucleic acids, pharmaceutical compositions, and production methods involving CdtB conjugated or fused to LF.
Protein comprising CdtB conjugated or fused to Bacillus anthracis toxin lethal factor
A protein comprising a cytolethal distending toxin subunit B (CdtB) conjugated or fused to Bacillus anthracis toxin lethal factor (LF) or a functional portion of LF.
Chimeric molecule including targeting moiety and/or Bacillus anthracis protective antigen fused to the protein
A chimeric molecule comprising (a) a targeting moiety, a Bacillus anthracis protective antigen (PA), or both, conjugated or fused to (b) the protein comprising CdtB conjugated or fused to LF.
Nucleic acid encoding the protein
A nucleic acid comprising a nucleotide sequence encoding the protein of CdtB conjugated or fused to LF.
Pharmaceutical composition including the protein with a pharmaceutically acceptable carrier
A pharmaceutical composition comprising the protein of CdtB conjugated or fused to LF and a pharmaceutically acceptable carrier, optionally further comprising one or more protective antigens (PAs).
Pharmaceutical composition further comprising one or more PAs
A pharmaceutical composition wherein the one or more PAs comprise wild-type PA (wtPA), PA-L1, PA-U2, PA-U7, PA-D512K, PA-GN, PA-NS, PA-R200A, or PA-I210A, optionally conjugated or fused to a targeting moiety.
Method of producing the protein by recombinant expression and purification
A method of producing the protein comprising recombinantly expressing the protein and purifying it.
Methods of producing the chimeric molecule
Methods including (a) recombinantly expressing and purifying the chimeric molecule, or (b) expressing and purifying the protein and then covalently linking a PA, a targeting moiety, or both to the protein.
The claims broadly cover the invention of a protein comprising CdtB conjugated or fused to LF, various chimeric molecules involving targeting moieties and protective antigens, nucleic acids encoding the protein, pharmaceutical compositions containing these proteins and compositions, and methods of producing these proteins and chimeric molecules.
Stated Advantages
Improved ability of the inventive protein to transit to the interior of target cells, leading to more efficient delivery of CdtB.
Higher intracellular delivery of CdtB enables greater cytotoxicity of target cells at lower dosages compared to unconjugated CdtB.
The inventive proteins may provide cytotoxic activity with little or no systemic toxicity or side effects.
The targeting moiety in chimeric molecules allows specific binding to cell surface markers, minimizing cross-reactivity and focusing cytotoxicity to target cells.
Documented Applications
Methods of treating or preventing a condition such as cancer in a mammal by administering the inventive protein, chimeric molecule, nucleic acid, recombinant expression vector, host cell, population of cells, or pharmaceutical composition.
Methods of inhibiting the growth of a target cell, including cancer cells and HIV-infected cells, by contacting the cell with the inventive protein, chimeric molecule, nucleic acid, recombinant expression vector, host cell, population of cells, or pharmaceutical composition.
Use in pharmaceutical compositions for administration to mammals to treat tumors or cancers, including a wide variety of cancer types listed in the patent.
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