CD44 ligation inhibits cell growth and increases the p27 content in THP1, KG1a, and HL60 AML cell lines. (A-B) Exponentially growing THP1, HL60, and KG1a cells were seeded in 96-well culture plates in complete culture medium supplemented with the anti-CD44 mAb A3D8 (2.5 μg/mL) or IgG1 (controls) and were cultured for 4 to 6 days at 37°C. (A) Cell counts and viability were evaluated by the trypan blue exclusion test. Data are means ± 1 SD calculated from 3 independent experiments. These figures are from Charrad et al.¹⁹  (B) p27 and α-tubulin expression were analyzed by Western blotting with specific antibodies 0, 24, and 48 hours after addition of A3D8. Results represent 1 representative experiment of 3. (C-D) THP-1 cells were infected with empty vector- or ASp27 retrovirus-containing medium and treated 2 days later with A3D8 (time 0) as described in “Materials and methods.” (C) Western blot analysis of p27 in empty vector- (controls) and ASp27-infected THP-1 cells treated with A3D8 for 0 hours and 24 hours. Protein levels were evaluated by densitometric scanning, corrected with respect to α-tubulin expression, and expressed relative to the value obtained in empty vector-infected cells at time 0 (arbitrarily 1). These relative protein level values are shown in italics below the lanes. Results represent 1 representative experiment of 2. (D) Empty vector- and ASp27-infected THP-1 cells were cultured at 37°C in the absence or presence of A3D8. Cell numbers and viability were evaluated in triplicate by the trypan blue exclusion test. Data are means ± 1 SD calculated from 3 independent experiments using quadruplicate samples. Data obtained in A3D8- and IgG1-treated ASp27-infected cells are nonsignificantly different (P > .05, Mann-Whitney test).