BMI1 and obstructive sleep apnea syndrome: To test the influence of BMI1 knockdown on drug-mediated cell toxicity, negative siRNA and BMI1 siRNA-1 treated Abrams OSA cells were exposed to increasing doses of Carbo (0, 0.5, and 0.75μM) or Dox (0, 2.5, 5.0nM) and evaluated in a clonogenic assay.