Figure 2

Status of the IAP proteins in a panel of malignant and non-malignant cell types in basal conditions and under stimulation by the poly(I:C). A) Variations in IAP protein concentrations in basal conditions and after 16 h of stimulation by poly(I:C) 500 ng/ml. The c-IAP1, c-IAP2 and XIAP relative concentrations were assessed by iterative staining of blotted membranes. β-actin was used as a loading control for density measurements. B) Exploration of the dose-effects relationships in c-IAP2 induction in HeLa cells treated for 16 h by poly(I:C) (TLR3 agonist) or CpG DNA (TLR9 agonist) at concentrations increasing from 50 to 2000 ng/ml. The same membrane was stained successively with anti-c-IAP2, c-IAP1 and β-actin. C) Western blot analysis of HeLa cells treated with poly(I:C) 500 ng/ml for increasing time intervals from 1 h to 48 h. The same membrane was stained successively with anti-c-IAP2, c-IAP1 and β-actin. D) Increase in c-IAP2 protein expression in malignant cells directly explanted in vitro from fresh human tumors. Cells were prepared for short term primary cultures from tumor biopsy fragments obtained from 2 patients designated A and B. These patients were referred for Head and Neck squamous cell carcinomas (see Methods section). Cells were incubated with poly(I:C) immediately after tumor dispersion for 16 h and collected for protein extraction and western blot analysis of c-IAP2 and β-actin expression. Data presented in A), B) and C) are representative of at least two similar experiments.