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. Author manuscript; available in PMC: 2012 Feb 24.
Published in final edited form as: Oncogene. 2010 Nov 8;30(8):1002–1008. doi: 10.1038/onc.2010.485

Figure 3. TGF-β receptor type I (TβRI) mediates collagen repression of let-7.

Figure 3

A. The mRNA isolated from Panc1 cells grown on plastic or in 3D type I collagen gels for 24 hours was analyzed by qRT-PCR for TGF-β1 expression with GAPDH as the endogenous control. *, p < 0.05 relative to cells grown on plastic. Data are an average of 3 separate experiments. B. The lysates were analyzed for pSmad2 and α-tubulin (loading control) by immunoblotting (left panel). Panc1 cells grown in 3D type I collagen gels were treated with DMSO (control) or TGF-β type I receptor (TβRI) inhibitor SB431542 (10 μM, TOCRIS, Ellisville, MO) for 24 hours and cell lysates immunoblotted for pSmad2 and α-tubulin (right panel). Data is representative of at least 2 separate experiments. C. Panc1 cells growing in 3D type I collagen gels were treated with DMSO or SB431542 and changes in MT1-MMP and let-7 monitored by qRT-PCR. *, p < 0.05 relative to DMSO-treated cells grown in collagen. Data are an average of 4 separate experiments. D. The protein lysates were immunoblotted for phospho-ERK1/2, ERK2 and α-tubulin (loading control). Data are representative of at least 3 separate experiments. E. Panc1 cells grown on plastic were induced with recombinant human TGF-β1 (10 ng/ml) for 24 hours; microRNA isolated from the cells was analyzed for let-7 by qRT-PCR from 3 separate experiments.