SIGNIFICANCE: These findings demonstrate that pre-existing, randomly distributed leader cells within primary tumor organoids use CXCR4 and DDR2 to polarize to the leading edge and direct migration.
The action of DDR2 in tumor CAFs is thus critical for remodeling collagen fibers at the tumor-stromal boundary to generate a physically permissive tumor microenvironment for tumor cell invasion and metastases.
Women with postsurgery residual disease, FIGO stage I/II - versus III/IV and DDR2 expression had worse OS, but only post-surgery residual disease remained an independent prognostic factor for worse OS in multivariable analysis. miR-182 expression levels were significantly lower in patients harboring tumors with higher expression of DDR2 (p < 0.001).
Western blot analysis of DDR1 and DDR2 expression in different tumor cell lines shows an absence of high co-expression of the two receptors suggesting a deleterious effect of their presence at high amount.
We discovered a novel concordant deregulation of DDR expression, with a DDR1(Low)/DDR2(High) profile significantly associated with TNBC, compared to luminal tumors (P = 0.012), and with worse overall survival.
An additional 23 matched tumour and normal tissues were tested for differential expression of DDR1 and DDR2, and previously reported somatic mutations.
When comparing array data with the chromosomal, mutational and clinical data we found that: a) loss of control of cellular transcription was of major relevance in this group of neoplasms, HMGA2 being one of the most overexpressed genes; b) gene expression correlated with the mutational status of PTCs, as in BRAF+ cases cMET and FN1 were concomitantly overexpressed; and c) death from disease and distant metastasis was associated to the overexpression of DDR2 and to the down-regulation of genes involved in immune, inflammatory response, signal transduction and cell adhesion processes.