Immunoblot analysis of DNA damage response. (A) CLL lymphocytes from patient 25 were cultured in suspension or on stroma. These were untreated or treated with bendamustine, fludarabine, or their combination for 8 or 24 hours and then harvested and lysed. Immunoblot analysis of the total and phosphoprotein levels of ATM, total and ser-15 phospho-p53, and total PUMA and Mcl-1 were analyzed. GAPDH was used as a loading control. (B) CLL lymphocytes from patients (35-38) were cultured in suspension and were untreated or treated with bendamustine, fludarabine, or their combination for 24 hours and then harvested and lysed. Immunoblot analysis of the total p53, PUMA, and GAPDH levels were analyzed. (C-D) CLL lymphocytes from patients (31-38) were cultured in suspension and were untreated or treated with bendamustine, fludarabine, or their combination for 24 hours and then harvested and lysed. Immunoblot analysis of the total and phospho thr-68 Chk2 (C) and total Chk1 (D) levels was done. GAPDH was used as a loading control. B, bendamustine; C, control (untreated); F, fludarabine.