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Figure 5 | BMC Cancer

Figure 5

From: Type IV collagen stimulates pancreatic cancer cell proliferation, migration, and inhibits apoptosis through an autocrine loop

Figure 5

Cellular effects of type IV collagen. A. Blocking of integrin α1, α2, and β1 resulted in reduced growth compared to control IgG (‡ indicates p<0.05 compared to index 1.0). Blocking of α1 and β1 showed dose dependency (*indicates p<0.05 compared to 1 μg/ml). B. Effects on cell growth after incubation with antibodies blocking different domains of type IV collagen, presented as relative growth compared to cells incubated with unspecific control IgG antibody (index 1.0). Blocking of the CB3-region reduces growth dose dependently (‡ indicates p<0.05 compared to index 1.0 and *indicates p<0.05 compared to 0.1 μg/cm2). C-1. Down-regulation of type IV collagen expression at the protein level (α1(IV) in red and DAPI in blue) and the mRNA level in α1(IV) siRNA transfected cells. C-2. Reduced cell growth after down-regulation of the α1(IV)-chain. ‡ indicates p<0.05. Growth inhibition was measurable after 20 hours and the effect sustained for 70 hours. Inserts illustrate differences in S-phase, p=0.03. C-3. Wound-healing assay for α1(IV)- and control-siRNA transfected cells. Picture-inserts represent the size of the wound at 83s, when the wound in the control cells was closed. *indicates p<0.05 compared to control transfected cells. C-4. Increased levels of the apoptotic M30-neoepitope were observed in α1(IV)-siRNA transfected cells (p=0.03). D. Under serum free conditions, α1(IV)-siRNA transfected cells show reduced growth. The cell growth is rescued if α1(IV)-siRNA transfected cells are grown on an exogenous type IV collagen matrix. Blocking of integrin β1 inhibits the rescue effect, whereas addition of a control IgG antibody does not. If α1(IV)-siRNA transfected cells are grown on an unspecific matrix (BSA), a small positive but non-significant effect on growth was observed. *indicates p<0.05 compared to α1(IV)-siRNA transfected cells grown without any coated matrix and without any blocking antibodies, and ‡ indicates p < 0.05 compared to control-siRNA transfected cells.

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