2.3. Tumor Grafting Experiments

Mice with fibroblast-specific deletion of MMP14 were generated by crossing a mouse line with floxed MMP14 gene to mice that express the estrogen receptor inducible Cre recombinase under control a fibroblast-specific regulatory fragment of the pro-α2 (I) collagen gene, as previously described [11]. For experimental skin fibrosis, we used an established mouse protocol [21]. Control mice were treated with intradermal injections of bleomycin (100 µg) (PZN-02411351, Medac GmbH, Wedel, Germany) five days a week for five weeks. Afterward, 0.5 × 10⁶ B16F1 cells were injected intradermally into the mice’s flank and tumor growth was followed and documented. Tumor size was measured using a precision caliper (Mitutoyo, Neuss, Germany) and mice were euthanized when they reached a maximal allowed tumor size. Tumors and organs were collected for further analysis.