Tissue multifractality and Born approximation in analysis of light scattering: a novel approach for precancers detection

Multifractal, a special class of complex self-affine processes, are under recent intensive investigations because of their fundamental nature and potential applications in diverse physical systems. Here, we report on a novel light scattering-based inverse method for extraction/quantification of multifractality in the spatial distribution of refractive index of biological tissues. The method is based on Fourier domain pre-processing via the Born approximation, followed by the Multifractal Detrended Fluctuation Analysis. The approach is experimentally validated in synthetic multifractal scattering phantoms, and tested on biopsy tissue slices. The derived multifractal properties appear sensitive in detecting cervical precancerous alterations through an increase of multifractality with pathology progression, demonstrating the potential of the developed methodology for novel precancer biomarker identification and tissue diagnostic tool. The novel ability to delineate the multifractal optical properties from light scattering signals may also prove useful for characterizing a wide variety of complex scattering media of non-biological origin

Stromal p53 Regulates Breast Cancer Development, the Immune Landscape, and Survival in an Oncogene-Specific Manner

International audienceCoevolution of tumor cells and adjacent stromal elements is a key feature during tumor progression; however, the precise regulatory mechanisms during this process remain unknown. Here, we show stromal p53 loss enhances oncogenic Kras(G12D), but not ErbB2, driven tumorigenesis in murine mammary epithelia. Stroma-specific p53 deletion increases both epithelial and fibroblast proliferation in mammary glands bearing the Kras(G12D) oncogene in epithelia, while concurrently increasing DNA damage and/or DNA replication stress and decreasing apoptosis in the tumor cells proper. Normal epithelia was not affected by stromal p53 deletion. Tumors with p53-null stroma had a significant decrease in total, cytotoxic, and regulatory T cells; however, there was a significant increase in myeloid-derived suppressor cells, total macrophages, and M2-polarized tumor-associated macrophages, with no impact on angio-genesis or connective tissue deposition. Stroma-specific p53 deletion reprogrammed gene expression in both fibroblasts and adjacent epithelium, with p53 targets and chemokine receptors/ chemokine signaling pathways in fibroblasts and DNA replication, DNA damage repair, and apoptosis in epithelia being the most significantly impacted biological processes. A gene cluster in p53- deficient mouse fibroblasts was negatively associated with patient survival when compared with two independent datasets. In summary, stroma-specific p53 loss promotes mammary tumorigenesis in an oncogene-specific manner, influences the tumor immune landscape, and ultimately impacts patient survival. Implications: Expression of the p53 tumor suppressor in breast cancer tumor stroma regulates tumorigenesis in an oncogene-specific manner, influences the tumor immune landscape, and ultimately impacts patient survival

Reprogramming of the tumour microenvironment by stromal PTEN-regulated miR-320

International audienc

Stromal PTEN determines mammary epithelial response to radiotherapy

© 2018 The Author(s). The importance of the tumor-associated stroma in cancer progression is clear. However, it remains uncertain whether early events in the stroma are capable of initiating breast tumorigenesis. Here, we show that in the mammary glands of non-tumor bearing mice, stromal-specific phosphatase and tensin homolog (Pten) deletion invokes radiation-induced genomic instability in neighboring epithelium. In these animals, a single dose of whole-body radiation causes focal mammary lobuloalveolar hyperplasia through paracrine epidermal growth factor receptor (EGFR) activation, and EGFR inhibition abrogates these cellular changes. By analyzing human tissue, we discover that stromal PTEN is lost in a subset of normal breast samples obtained from reduction mammoplasty, and is predictive of recurrence in breast cancer patients. Combined, these data indicate that diagnostic or therapeutic chest radiation may predispose patients with decreased stromal PTEN expression to secondary breast cancer, and that prophylactic EGFR inhibition may reduce this risk

Ets2 in Tumor Fibroblasts Promotes Angiogenesis in Breast Cancer

<div><p>Tumor fibroblasts are active partners in tumor progression, but the genes and pathways that mediate this collaboration are ill-defined. Previous work demonstrates that <i>Ets2</i> function in stromal cells significantly contributes to breast tumor progression. Conditional mouse models were used to study the function of <i>Ets2</i> in both mammary stromal fibroblasts and epithelial cells. Conditional inactivation of <i>Ets2</i> in stromal fibroblasts in <i>PyMT</i> and <i>ErbB2</i> driven tumors significantly reduced tumor growth, however deletion of <i>Ets2</i> in epithelial cells in the <i>PyMT</i> model had no significant effect. Analysis of gene expression in fibroblasts revealed a tumor- and <i>Ets2-</i>dependent gene signature that was enriched in genes important for ECM remodeling, cell migration, and angiogenesis in both <i>PyMT</i> and <i>ErbB2</i> driven-tumors. Consistent with these results, <i>PyMT</i> and <i>ErbB2</i> tumors lacking <i>Ets2</i> in fibroblasts had fewer functional blood vessels, and <i>Ets2</i> in fibroblasts elicited changes in gene expression in tumor endothelial cells consistent with this phenotype. An <i>in vivo</i> angiogenesis assay revealed the ability of <i>Ets2</i> in fibroblasts to promote blood vessel formation in the absence of tumor cells. Importantly, the <i>Ets2</i>-dependent gene expression signatures from both mouse models were able to distinguish human breast tumor stroma from normal stroma, and correlated with patient outcomes in two whole tumor breast cancer data sets. The data reveals a key function for <i>Ets2</i> in tumor fibroblasts in signaling to endothelial cells to promote tumor angiogenesis. The results highlight the collaborative networks that orchestrate communication between stromal cells and tumor cells, and suggest that targeting tumor fibroblasts may be an effective strategy for developing novel anti-angiogenic therapies.</p></div

<i>Ets2</i> deletion in stromal fibroblasts reduces size and number of tumor lesions in <i>ErbB2</i> breast cancer model.

<p><b>A.</b> Left: graph represents carcinoma lesion sizes in mm² from 16 week old <i>ErbB2;Ets2^db/loxP</i> (n = 5, 2.28±4.16) and <i>ErbB2;Fsp-Cre;Ets2^db/loxP</i> (n = 5, 1.83±7.96) mice (**P<0.01, Non-parametric Mann-Whitney test). Right: graph represents number of lesions larger than one mm² in mammary glands of 16 week old <i>ErbB2;Ets2^db/loxP</i> (n = 5) and <i>ErbB2;Fsp-Cre;Ets2^db/loxP</i> (n = 5) mice (**P<0.01, Chi Square test). <b>B.</b> Representative H&E stained mammary glands from 16 week old <i>ErbB2;Ets2^db/loxP</i> and <i>ErbB2;Fsp-Cre;Ets2^db/loxP</i> mice. Scale bar, 2mm. LN, lymph node. T, tumor. <b>C.</b> Representative histological sections from mammary glands of 16 week old <i>ErbB2;Ets2^db/loxP</i> and <i>ErbB2;Fsp-Cre;Ets2^db/loxP</i> mice. Scale bar, 50 µm. <b>D.</b> Left: representative IHC staining for Ki67 in mammary glands from 16 week old <i>ErbB2;Ets2^db/loxP</i> and <i>ErbB2;Fsp-Cre;Ets2^db/loxP</i> mice. Scale bar, 50 µm. Right: graph represents percentage of Ki67 positive epithelial cells (n = 3, bars represent means ± SD, *<i>*</i>P<0.01, Welch’s t-test assuming unequal variance).</p

<i>Ets2</i> in fibroblasts controls tumor angiogenesis.

<p><b>A.</b> Left: <i>in vivo</i> tumor vasculature visualized by intracardiac injection of FITC lectin (green). Scale bar, 200 µm. Right: graph represents percent lectin positive area quantified using ImageJ, Fiji(n = 3, bars represent means ± SD, *<i>*</i> P<0.01, Welch’s t-test assuming unequal variance). <b>B.</b> Left: immunofluorescence staining for CD31 (red) in mammary gland tumors from 10 week old <i>PyMT;Ets2^db/loxP</i> and <i>PyMT;Fsp-Cre;Ets2^db/loxP</i> mice. Scale bar, 200 µm. Slides were counterstained with DAPI (blue). Right: graph represents percent CD31 positive area quantified using ImageJ, Fiji (n = 3, bars represent means ± SD, *<i>*</i>P<0.01, Welch’s t-test assuming unequal variance). <b>C.</b> Left: i<i>n vivo</i> tumor vasculature visualized by intrafemoral injection of DyLight 594 lectin (green). Scale bar, 200 µm. Right: graph represents percent lectin positive area quantified using ImageJ, Fiji (n = 3, bars represent means ± SD, *<i>*</i> P<0.01, Welch’s t-test assuming unequal variance). <b>D.</b> Left: immunofluorescence staining for CD31 (red) in mammary gland tumors from 16 week old <i>ErbB2;Ets2^db/loxP</i> and <i>ErbB2;Fsp-Cre;Ets2^db/loxP</i> mice. Scale bar, 200 µm. Slides were counterstained with DAPI (blue). Right: graph represents percent CD31 positive area quantified using ImageJ, Fiji (n = 3, bars represent means ± SD, *<i>*</i>P<0.01, Welch’s t-test assuming unequal variance). <b>E.</b> Heatmap depicting the genes significantly differentially regulated in endothelial cells isolated from <i>PyMT;Ets2^db/loxP</i> vs. <i>PyMT;Fsp-Cre;Ets2^db/loxP</i> mammary glands harvested at 9 weeks (n = 3, fold change>2, *P≤0.05). <b>F.</b> GSEA plots depicting ECM remodeling, cell adhesion and cell chemotaxis to be enriched in endothelial cells isolated from <i>PyMT;Ets2^db/loxP</i> mammary glands as compared to <i>PyMT;Fsp-Cre;Ets2^db/loxP</i> mammary glands. NES: normalized enrichment score.</p

<i>Ets2</i> regulates tumor fibroblast specific transcription program.

<p><b>A.</b> Heatmap representing expression levels of 107 upregulated and downregulated genes in <i>PyMT;Ets2^db/loxP</i> vs. <i>PyMT;Fsp-Cre;Ets2^db/loxP</i> fibroblasts in all indicated genotypes harvested from 9 week old mice (n = 1, Log fold change>2, Negative Log P value (NLP)>4.5). <b>B.</b> GSEA plots depicting ECM remodeling, angiogenesis, cell growth and cell migration to be enriched in <i>PyMT;Ets2^db/loxP</i> fibroblasts as compared to <i>PyMT;Fsp-Cre;Ets2^db/loxP</i> fibroblasts. NES: normalized enrichment score. <b>C.</b> Heatmap representing expression levels of 69 upregulated and downregulated genes in <i>ErbB2;Ets2^db/loxP</i> vs. <i>ErbB2;Fsp-Cre;Ets2^db/loxP</i> fibroblasts in all indicated genotypes harvested from 16 week old mice (n = 1, Log fold change>2). <b>D.</b> GSEA plots depicting ECM remodeling, angiogenesis, cell growth and cell migration to be enriched in <i>ErbB2;Ets2^db/loxP</i> fibroblasts as compared to <i>ErbB2;Fsp-Cre;Ets2^db/loxP</i> fibroblasts. NES: normalized enrichment score. <b>E.</b> Venn diagrams depicting the number of common genes in the leading edge subset of indicated GO categories enriched in <i>PyMT;Ets2^db/loxP</i> fibroblasts (gray circles) and <i>ErbB2;Ets2^db/loxP</i> fibroblasts (white circles).</p