Integrin alpha 11 regulates IGF2 expression in fibroblasts to enhance tumorigenicity of human non-small-cell lung cancer cells

• Published in: Proceedings of the National Academy of Sciences - PNAS 2007-07, Vol.104 (28), p.11754-11759
• Main Authors: Zhu, Chang-Qi, Popova, Svetlana N, Brown, Ewan R S, Barsyte-Lovejoy, Dalia, Navab, Roya, Shih, Warren, Li, Ming, Lu, Ming, Jurisica, Igor, Penn, Linda Z, Gullberg, Donald, Tsao, Ming-Sound
• Format: Article
• Language: English
• Subjects: Adenocarcinoma - genetics; Adenocarcinoma - metabolism; Adenocarcinoma - pathology; Animals; Carcinoma, Non-Small-Cell Lung - genetics; Carcinoma, Non-Small-Cell Lung - metabolism; Carcinoma, Non-Small-Cell Lung - pathology; Carcinoma, Squamous Cell - genetics; Carcinoma, Squamous Cell - metabolism; Carcinoma, Squamous Cell - pathology; Cell Line, Transformed; Cell Line, Tumor; Collagen - metabolism; Extracellular Matrix - genetics; Extracellular Matrix - metabolism; Extracellular Matrix - pathology; Fibroblasts - metabolism; Gene Expression Regulation, Neoplastic - physiology; Growth Substances - biosynthesis; Growth Substances - genetics; Growth Substances - physiology; Humans; Insulin-Like Growth Factor II; Integrin alpha Chains - deficiency; Integrin alpha Chains - genetics; Integrin alpha Chains - physiology; Lung Neoplasms - genetics; Lung Neoplasms - metabolism; Lung Neoplasms - pathology; Male; Mice; Mice, Knockout; Mice, SCID; Proteins - genetics; Proteins - metabolism; Stromal Cells - metabolism; Stromal Cells - pathology
• ISSN: 0027-8424; 1091-6490

Integrin alpha11 (ITGA11/alpha11) is localized to stromal fibroblasts and commonly overexpressed in non-small-cell lung carcinoma (NSCLC). We hypothesized that stromal alpha11 could be important for the tumorigenicity of NSCLC cells. SV40 immortalized mouse embryonic fibroblasts established from wild-type (WT) and Itga11-deficient [knockout (KO)] mice were tested for their tumorigenicity in immune-deficient mice when implanted alone or coimplanted with the A549 human lung adenocarcinoma cells. A549 coimplanted with the fibroblasts showed a markedly enhanced tumor growth rate compared with A549, WT, or KO, which alone formed only small tumors. Importantly, the growth was significantly greater for A549+WT compared with A549+KO tumors. Reexpression of human alpha11 cDNA in KO cells rescued a tumor growth rate to that comparable with the A549+WT tumors. These findings were validated in two other NSCLC cell lines, NCI-H460 and NCI-H520. Gene expression profiling indicated that IGF2 mRNA expression level was >200 times lower in A549+KO compared with A549+WT tumors. Stable short-hairpin RNA (shRNA) down-regulation of IGF2 in WT (WT(shIGF2)) fibroblasts resulted in a decreased growth rate of A549+WT(shIGF2), compared with A549+WT tumors. The results indicate that alpha11 is an important stromal factor in NSCLC and propose a paradigm for carcinoma-stromal interaction indirectly through interaction between the matrix collagen and stromal fibroblasts to stimulate cancer cell growth.