Methods of determining cellular chemosensitivity

1. A method comprising:

(a) providing a cancer cell sample;

(b) permeabilizing a first aliquot of cells from the cancer cell sample;

(c) contacting the first aliquot of permeabilized cells with a first purified BH3 domain peptide of 50 amino acids or less;

(d) measuring the first BH3 domain peptide-induced mitochondrial outer membrane permeabilization (MOMP) in the first aliquot of cells;

(e) permeabilizing a second aliquot of cells from the cancer cell sample;

(f) contacting the second aliquot of permeabilized cells with a second purified BH3 domain peptide of 50 amino acids or less, wherein the first BH3 domain peptide and the second BH3 domain peptide are derived from different BCL-2 proteins;

(g) measuring the second BH3 domain peptide-induced MOMP in the second aliquot of cells; and

(h) determining a test BH3 profile for the cancer cell sample based on the first BH3 domain peptide-induced MOMP measured in (d) and the second BH3 domain peptide-induced MOMP measured in (g).

2. The method of claim 1 , further comprising contacting said permeabilized cells with a potentiometric dye.

3. The method of claim 2 , wherein said potentiometric dye is JC-1 or dihydrorhodamine 123.

4. The method of claim 2 , wherein the MOMP is measured by detecting a change in emission of said potentiometric dye.

5. The method of claim 1 , wherein said BH3 domain peptides are each independently derived from the BH3 domain of a BID, a BIM, a BAD, a BIK, a NOXA, a PUMA a BMF, or a HRK polypeptide.

6. The method of claim 1 , wherein said BH3 domain peptides are each independently selected from the group consisting of SEQ ID NO: 1-14 and 15.

7. The method of claim 1 , further comprising:

(i) contacting one or more additional aliquots of permeabilized cells from the cancer cell sample each with an additional purified BH3 domain peptide of 50 amino acids or less, wherein the first BH3 domain peptide, the second BH3 domain peptide, and the additional purified BH3 domain peptides are each derived from different BCL-2 proteins; and

(j) measuring the BH3 domain peptide-induced MOMP in each of the one or more additional aliquots of cells,

wherein the test BH3 profile is determined based on the BH3 domain peptide-induced MOMP measured in (j).

8. The method of claim 1 , wherein the MOMP is measured by measuring the release of a molecule from a mitochondrion.

9. The method of claim 8 , wherein the molecule from the mitochondrion is cytochrome c.

10. The method of claim 1 , wherein the cells are permeabilized by contacting the cells with digitonin.