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
• Main Authors: Chang-Qi, Zhu, Popova, Svetlana N, Brown, Ewan R S, Barsyte-Lovejoy, Dalia
• Format: Article
• Language: English
• Subjects: Cells; Lung cancer; Proteins; Rodents; Tumors
• ISSN: 0027-8424; 1091-6490

Integrin α11 (ITGA11/α11) is localized to stromal fibroblasts and commonly overexpressed in non-small-cell lung carcinoma (NSCLC). We hypothesized that stromal α11 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 all 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 (...) fibroblasts resulted in a decreased growth rate of A349+..., compared with A549+WT tumors. The results indicate that α11 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. (ProQuest-CSA LLC: ... denotes formulae/symbols omitted.)