Knockdown of MMP1/13 abrogates invasion of C4-1 and CaSki cells.

C4-1 and CaSki cells were transfected with indicated siRNAs. After 48 hours, equal number of cells were seeded in the upper part of Matrigel invasion chambers, in DMEM without serum. DMEM with 10% of serum was used as a chemoattractant in the lower chamber. After 22h, cells that had invaded the lower chamber were fixed and stained with 0.5% Crystal Violet in 5% glutaraldehyde for 10 mins. (A and D) Representative micrographs showing invasive cells from each siRNA treatment as indicated. (B and E) Quantification of the mean number of invasive cells per field shown as bars with the standard error of mean obtained from at least 4 separate fields. Asterisks indicate the p-value of mean numbers of invasive cells, compared with the wild type cells. (C and F) Western blot analysis of concentrated conditioned medium from indicated siRNA treatments for MMP1 and MMP13.