Targeting intracellular target-binding determinants with intracellular antibodies
The invention provides a method for inhibiting an intracellular target in a cell with a bispecific antibody comprising contacting the cell with a bispecific antibody having a first Fv fragment with a cell-penetrating determinant and a second Fv fragment with an intracellular target-binding determinant under suitable conditions so that the first Fv fragment causes the bispecific antibody to enter the cell and the second Fv fragment binds the intracellular target in the cell and thereby inhibiting the intracellular target.
1. A method for inhibiting the growth of tumor or cancer cells associated with Mdm2, MDC1, 53BP1, ATR, CHK1, CHK2, or p21 expression or activity in a subject by exposing the tumor or cancer cells to a bispecific antibody having a first Fv fragment with a cell-penetrating determinant of a 3E10 monoclonal antibody and a second Fv fragment with an intracellular target-binding determinant that inhibits an intracellular target under suitable conditions so that the first Fv fragment causes the bispecific antibody to enter the cells and the second Fv fragment binds the intracellular target in the cells and inhibits the intracellular target, wherein the first Fv fragment comprises a heavy chain variable domain comprising the following complementarity determining region (CDR) amino acid sequences:
a. CDRH1 comprising SEQ ID NO: 11,
b. CDRH2 comprising SEQ ID NO: 13 and
c. CDRH3 comprising SEQ ID NO: 15; and,
a light chain variable domain comprising the following complementarity determining region (CDR) amino acid sequences:
a. CDRL1 comprising SEQ ID NO: 5,
b. CDRL2 comprising SEQ ID NO: 7, and
c. CDRL3 comprising SEQ ID NO: 9;
wherein the second Fv binds Mdm2, MDC1, 53BP1, ATR, CHK1, CHK2, or p21 protein, thereby inhibiting the growth of tumor or cancer cells that express Mdm2, MDC1, 53BP1, ATR, CHK1, CHK2, or p21 protein in the subject.
2. The method of claim 1 , wherein the bispecific antibody has the amino acid sequence of SEQ ID NO:2 or 3.
3. The method of claim 1 , wherein the bispecific antibody is encoded by the nucleic acid sequence as shown in SEQ ID NO:1.
4. The method of claim 1 , wherein the bispecific antibody is chimeric, human or humanized.
5. The method of claim 1 , wherein the second Fv fragment with an intracellular target-binding determinant is derived from an anti-oncoprotein antibody or an anti-idiotypic antibody of an anti-oncoprotein antibody.
6. The method of claim 5 , wherein the anti-oncoprotein antibody or the anti-idiotypic antibody is a monoclonal antibody.
7. The method of claim 6 , wherein the monoclonal antibody binds the Mdm2 oncoprotein.
8. The method of claim 7 , wherein the monoclonal antibody that binds the Mdm2 oncoprotein is mAb 3G5.
9. The method of claim 1 , wherein the bispecific antibody comprises the second Fv fragment comprising (a) a light chain variable domain comprising complementarity determining regions of 3G5 monoclonal antibody and (b) a heavy chain variable domain comprising complementarity determining regions of 3G5 monoclonal antibody.
10. The method of claim 9 , wherein the complementarity determining regions of the second Fv fragment comprising a light chain variable domain has an amino acid sequence as provided in SEQ ID NO:17 for CDR1, SEQ ID NO:19 for CDR2 and SEQ ID NO:21 for CDR3.
11. The method of claim 9 , wherein the complementarity determining regions of the second Fv fragment comprising a heavy chain variable domain has an amino acid sequence as provided in SEQ ID NO:23 for CDR1, SEQ ID NO:25 for CDR2 and SEQ ID NO:27 for CDR3.
12. The method of claim 9 , wherein the bispecific antibody comprises the second Fv fragment comprising (a) a light chain variable domain comprising complementarity determining regions of 3G5 monoclonal antibody having an amino acid sequence as provided in SEQ ID NO:17 and encoded by a nucleic acid sequence as provided in SEQ ID NO:16 or equivalent for CDR1, SEQ ID NO:19 and encoded by a nucleic acid sequence as provided in SEQ ID NO:18 or equivalent for CDR2 and SEQ ID NO:21 and encoded by a nucleic acid sequence as provided in SEQ ID NO:20 or equivalent for CDR3; and (b) a heavy chain variable domain comprising complementarity determining regions of 3E10 monoclonal antibody (ATCC Accession No. PTA 2439) having an amino acid sequence as provided in SEQ ID NO:23 and encoded by a nucleic acid sequence as provided in SEQ ID NO:22 or equivalent for CDR1, SEQ ID NO:25 and encoded by a nucleic acid sequence as provided in SEQ ID NO:24 or equivalent for CDR2 and SEQ ID NO:27 and encoded by a nucleic acid sequence as provided in SEQ ID NO:26 or equivalent for CDR3, wherein equivalent refers to degeneracy of genetic code allowing multiple codons to code for the same amino acid.
13. The method of claim 1 , wherein the bispecific antibody is encoded by a nucleic acid sequence comprising the nucleic acid sequence as shown in SEQ ID NO:1 from nucleotide position 268 to 1833.
14. The method of claim 4 , wherein the chimeric, the human or the humanized antibody competes with anti-DNA monoclonal antibody 3E10 for binding to DNA.