title: Extracellular protease mRNAs are predominantly expressed in the stromal areas of microdissected mouse breast carcinomas.
abstract: Solid tumors synthesize a number of extracellular matrix-degrading proteases that are important for tumor progression. Based on qualitative in situ hybridization studies in human cancer tissue, a range of components involved in proteolysis appear to be expressed by stromal cells rather than cancer cells. We have now used laser capture microdissection and real-time PCR to quantify the mRNA expression of components of matrix-degrading proteolytic systems in cancer and stromal areas of mouse mammary tumors genetically induced by the polyoma virus middle T (PyMT) antigen. We examined the mRNA levels of urokinase plasminogen activator, plasminogen activator inhibitor 1 and the matrix metalloproteases MMP-2, -3, -11, -13 and -14, and found that all these seven genes are predominantly expressed by stromal cells. Our results were qualitatively supported by in situ hybridization analysis of the expression of mRNAs for MMP-2, -3 and -13 in the PyMT tumors. Statistical analyses indicated that the quantitative expression patterns observed in cancer and stromal cells isolated from individual tumors from different PyMT mice are quite reproducible. The methodology described in this study provides excellent tools to study the possible interactions between cancer and stromal cells during the development of breast cancer, and the results suggest that stromal cells are involved in carcinogenesis and tumor progression, which may have important implications for the biology and therapy of cancer.
authors.affiliation: Finsen Laboratory, Rigshospitalet, Strandboulevarden 49, DK-2100 Copenhagen, Denmark.
authors.forename: Tanja Xenia
authors.initials: TX
authors.lastname: Pedersen
authors.forename: Caroline J
authors.initials: CJ
authors.lastname: Pennington
authors.forename: Kasper
authors.initials: K
authors.lastname: Almholt
authors.forename: Ib Jarle
authors.initials: IJ
authors.lastname: Christensen
authors.forename: Boye Schnack
authors.initials: BS
authors.lastname: Nielsen
authors.forename: Dylan R
authors.initials: DR
authors.lastname: Edwards
authors.forename: John
authors.initials: J
authors.lastname: Rømer
authors.forename: Keld
authors.initials: K
authors.lastname: Danø
authors.forename: Morten
authors.initials: M
authors.lastname: Johnsen
mesh_terms: D000818:Animals; D002277:Carcinoma / Q000235:genetics* / Q000662:veterinary; D005260:Female; D015674:Mammary Neoplasms, Animal / Q000235:genetics*; D051379:Mice; D010447:Peptide Hydrolases / Q000096:biosynthesis*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D015203:Reproducibility of Results; D017154:Stromal Cells
chemical_list: D012333:RNA, Messenger; D010447:Peptide Hydrolases