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Figure 2. Asbestos-induced MMPs are regulated via an EGFR (or other growth factor receptors)/PI3K/PKC
/ERK1/2 pathway. Lung epithelial type II cells (C10) (MMP13, TIMP1) and primary lung fibroblasts (MMP12) were pretreated with either (A) a mitogen-activated protein kinase (ERK1/2) inhibitor (U1026 10 µM for 1 h), (B) a phosphatidylinositol 3-kinase (PI3K) inhibitor (LY 294002, 10 or 20 µM for 1 h), or an EGF receptor inhibitor (AG1478, 10 or 20 µM for 1 h) or (C) a protein kinase C general inhibitor (Bis 5 µM for 1 h) or PKC specific inhibitor (rottlerin 5 µM for 1 h), before exposing them to asbestos (5 µg/cm2) for 24 h. RNA was prepared and analyzed by a ribonuclease protection assay (RPA). Quantitation of autoradiograms was performed using a phosphoimager. *P 
0.05 compared with untreated control, #P 0.05 as compared to asbestos-exposed group.
