This Data Analysis Problem does not appear in the textbook.

Source:  Druker, B. J., M. Talpaz, D. J. Resta, B. Peng, E. Buchdunger, J. M. Ford, N. B. Lydon, H. Kantorjian, R. Capderille, S. Ohno-Jones, C. L. Sawyers. 2001. Efficacy and Safety of a Specific Inhibitor of the BCR-ABL Tyrosine Kinase in Chronic Myeloid Leukemia. N. Engl. J. Med. 344: 1031–1037.

Corresponding chapter(s) in the textbook: Chapter 19

Review the following terms before working on the problem: Gleevec, Philadelphia chromosome, chronic myeloid leukemia (CML), white blood cells (leukocytes), Western blot (immunoblot) analysis, adapter protein, BCR-ABL fusion protein

Experiment

Gleevec is a powerful signal transduction drug routinely used for the treatment of Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia (CML). In a clinical trial carried out at the time of its approval for human use, five CML patients were treated with daily oral doses of Gleevec, as indicated in the figure. Participant blood samples were collected before exposure to the drug (samples 1, 3, 5, 7, and 9), and two hours after the second treatment (samples 2, 4, 6, 8, and 10). White blood cells were isolated, cell extracts were prepared, and immunoblot analysis was performed using an anti-CRKL antibody. (Note: CRKL is an adapter protein that is the main endogenous substrate of the BCR-ABL protein in neutrophil leukocytes.)

Figure

Source: Druker, B. J., M. Talpaz, D. J. Resta, B. Peng, E. Buchdunger, J. M. Ford, N. B. Lydon, H. Kantorjian, R. Capderille, S. Ohno-Jones, C. L. Sawyers. 2001. Efficacy and Safety of a Specific Inhibitor of the BCR-ABL Tyrosine Kinase in Chronic Myeloid Leukemia. N. Engl. J. Med. 344: 1031–1037.

Questions

1. What is characteristic of Ph+ CML?

2. Describe the state of CRKL protein in the leukemia cells.

3. Describe the effect of Gleevec.

4. What may have caused the difference seen in patient 1’s results?

5. What technique could be used to prove that the upper and lower bands correspond to phosphorylated and unphosphorylated CRKL, respectively?