Modulating expression of polypeptides via new gene switch expression systems

1. A vector comprising a polynucleotide encoding: (a) a first gene switch polypeptide comprising a transactivation domain fused to a first ligand binding domain; and (b) a second gene switch polypeptide comprising a DNA binding domain fused to a second ligand binding domain, wherein:

the first and second gene switch polypeptides are connected by a polypeptide linker; and

the first gene switch polypeptide comprises an amino acid sequence having at least 90% identity with SEQ ID NO: 183 and/or the second gene switch polypeptide comprises an amino acid sequence having at least 90% identity with SEQ ID NO: 187 or 188.

2. The vector of claim 1 , wherein the vector is a Sleeping Beauty transposon.

3. The vector of claim 1 , wherein the vector comprises one or more recombinase attachment sites.

4. The vector of claim 1 , wherein the polypeptide linker comprises a cleavable linker sequence.

5. The vector of claim 1 , wherein expression of the first and second gene switch polypeptides are modulated by a constitutive promoter.

6. The vector of claim 1 , wherein the vector is a lentivirus vector, a retroviral vector, or a non-viral vector.

7. A method of stimulating the proliferation and/or survival of engineered cells, the method comprising transfecting a cell obtained from a subject with:

(a) the vector of claim 1 ;

(b) a polynucleotide comprising a transposon encoding a chimeric antigen receptor or a T cell receptor; and

(b) one or more polynucleotides encoding a cytokine, a cell tag and a transposase effective to integrate the transposon into the genome of the cell.

8. A gene switch system for ligand-inducible control of heterologous gene expression, the gene switch system comprising:

(a) the vector of claim 1 ; and

(b) a vector comprising a heterologous gene under the control of a ligand-inducible promoter.

9. The gene switch system of claim 8 , wherein the vector of (a) further comprises a polynucleotide sequence encoding a chimeric antigen receptor, the expression of which is modulated by a non-inducible promoter.

10. The gene switch system of claim 9 , wherein the chimeric antigen receptor is capable of binding at least one of CD19, CD33, BCMA, CD44, a-Folate receptor, CAIX, CD30, ROR1, CEA, EGP-2, EGP-40, HER2, HER3, Folate-binding Protein, GD2, GD3, IL-13R-a2, KDR, EDB-F, mesothelin, CD22, EGFR, MUC-1, MAGE-Al, MUC-16, h5T4, PSMA, TAG-72, EGFRvIII, CD123, and VEGF-R2.

11. The gene switch system of claim 8 , wherein the vector of (b) further comprises a polynucleotide sequence encoding a cell tag.

12. The gene switch system of claim 11 , wherein the cell tag comprises a HER1 truncated variant and/or a CD20 truncated variant.

13. The gene switch system of claim 12 , wherein the cell tag comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 189 or 190.

14. The gene switch system of claim 12 , wherein the cell tag comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 190.

15. The gene switch system of claim 8 , wherein the ligand-inducible promoter comprises the polynucleotide sequence of any one of SEQ ID NOs: 40-64.

16. The gene switch system of claim 8 , wherein the DNA binding domain comprises the amino acid sequence of SEQ ID NO: 184.

17. The gene switch system of claim 8 , wherein the transactivation domain comprises the amino acid sequence of SEQ ID NO: 181.

18. The gene switch system of claim 8 , wherein at least one of the first and second ligand binding domains comprises an amino acid sequence that is at least 90% identical to any one of SEQ ID NOs: 182, 185, and 186.

19. The gene switch system of claim 8 , wherein the heterologous gene encodes a cytokine.

20. The gene switch system of claim 19 , wherein the cytokine is IL-1, IL-2, IL-15, IL-12, IL-21, a fusion of IL-15 and IL-15Ra, or an IL-15 variant.

21. The gene switch system of claim 19 , wherein the heterologous gene encodes a fusion polypeptide comprising: IL-15 or a functional variant thereof; and IL-15Rα or a functional variant thereof.

22. The gene switch system of claim 21 , wherein the fusion polypeptide is connected to a cell tag by a polypeptide linker.

23. The gene switch system of claim 21 , wherein the fusion polypeptide comprises: (a) an amino acid sequence of SEQ ID NO: 203 or functional variant thereof; and (b) an amino acid sequence of SEQ ID NO: 204 or a functional variant thereof.

24. The gene switch system of claim 8 , wherein the polypeptide linker comprises a 2A linker, a p2A linker, a T2A linker, a F2A linker, an E2A linker, a GSG-2A linker, or one or more derivatives thereof.

25. The gene switch system of claim 8 , wherein the polypeptide linker comprises an amino acid sequence having at least 90% sequence identity with any one of SEQ ID NOs: 153-160.

26. The gene switch system of claim 8 , wherein:

(a) the ligand-inducible promoter comprises the polynucleotide sequence of any one of SEQ ID NOs: 40-64; and

(b) the polypeptide linker comprises a 2A linker, a p2A linker, a T2A linker, a F2A linker, an E2A linker, or a GSG-2A linker.

27. The gene switch system of claim 26 , wherein expression of the first and second gene switch polypeptides are modulated by an EF1A promoter or a functional variant thereof.

28. The gene switch system of claim 27 , wherein the EF1A promoter or functional variant thereof comprises a polynucleotide sequence of any one of SEQ ID NOs: 58-60.

29. A method of regulating the expression of a heterologous gene in an effector cell, the method comprising introducing into the effector cell the gene switch system of claim 8 and contacting the effector cell with a ligand in an amount sufficient to induce expression of the heterologous gene.

30. The method of claim 29 , wherein the heterologous gene encodes an antigen-binding polypeptide.

31. The method of claim 30 , wherein the antigen-binding polypeptide selectively binds a predetermined cell surface protein of a target cell.

32. The method of claim 31 , wherein the target cell is a mammalian cell.