Fig. 4. Mitochondrial stress-induced cell invasion in C2C12 myoblasts and A549 lung carcinoma cells. In vitro Matrigel assays were carried out using ³H-labeled cells as described in Materials and methods. Treatment with indicated levels of CCCP and cyclosporin was carried out for 5 h, and other treatments were as described in Materials and methods. (A) In vitro invasion of C2C12 cells in Matrigel chambers. (B) Effects of CCCP on the induction cathepsin L protein in A549 cells. Immunoblot analysis of whole-cell extracts (50 µg protein each) was carried out with antibody to human cathepsin L (Santacruz Biotech., 1:1000 dilution). The blot was also reprobed with antibody to ubiquitous transcription factor YY1 as a loading control. (C) In vitro Matrigel invasion with treated and untreated A549 cells. The values represent mean ± SEM of four independent experiments.