Virtual Library

Start Your Search

R. Navab



Author of

  • +

    MINI 35 - Biology (ID 161)

    • Event: WCLC 2015
    • Type: Mini Oral
    • Track: Biology, Pathology, and Molecular Testing
    • Presentations: 1
    • +

      MINI35.08 - Functional Role of Cancer Associated Fibroblasts in Non-Small Cell Lung Cancer Patients (ID 3134)

      18:30 - 20:00  |  Author(s): R. Navab

      • Abstract
      • Slides

      Background:
      Cancer-associated fibroblasts (CAFs) are well known to strongly influence tumor development, progression and metastasis. Their characteristics and prognostic role in non-small cell lung cancer (NSCLC) patients have been recognized. However, the functional heterogeneity of CAFs between patients and their genetic basis are less understood.

      Methods:
      Primary cultures of CAFs and noncancer fibroblasts were established from 28 independent resected non-small cell lung cancers and their corresponding non-neoplastic lung parenchyma. Collagen gel contraction, xCELLigence Real-Time Cell Analysis of proliferation and in vivo tumorigenicity were studied to assess the CAF activity. Percent area of desmoplasia among total tumor stroma was used to define high desmoplasia (HD) versus low desmoplasia (LD). Gene expression data on RNA extracted from contracted gels following 8 hours incubation was obtained using Illumina Human HT-12v4 Bead Chips array and was preprocessed and normalized using RMA and values were log2 transformed. Two-fold change cutoff was applied to identify differentially expressed genes in CAF-HD versus CAF-LD.

      Results:
      High desmoplasia correlates with higher ability to contract collagen gel, increased cell proliferation and tumor growth. Microarray gene expression analysis of the 24 CAF cell lines identified 23 genes that were differentially expressed between 12 CAF-HD versus 12 CAF-LD lines and were correlated significantly (p ≤ 0.05) with the gel contraction. 23 differentially gene expression were evaluated in gene expression microarray data (Affymetrix HG-U133 Plus 2 Array) from 181 NSCLC patients. We found 7 out of 23 differential gene expression to be significantly in concordant with the cohort of 181 NSCLC patients. Taking 7 prioritized genes, we have generated physical protein-protein interaction network by quering I2D ver. 3 and visualizing it in NAViGaTOR ver 2.3 (http://ophid.utoronto.ca/navigator). To study the degree of desmoplasia and outcome, we used the cohort of 181 NSCLC patients data set. We observed that desmoplasia appears to be associated with the time to relapse in univariable analysis. The association was far stronger in the adenocarcioma group with significance for both univariable and multivariable analysis.

      Conclusion:
      We provide evidence for a functional heterogeneity of CAFs in NSCLC patients based on the level of desmoplasia in tumor stroma. Furthermore, we develop desmoplasia-specific gene signature that could subgroup CAFs and contribute to their functional heterogeneity.

      Only Active Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login or select "Add to Cart" and proceed to checkout.

  • +

    P1.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 233)

    • Event: WCLC 2015
    • Type: Poster
    • Track: Biology, Pathology, and Molecular Testing
    • Presentations: 1
    • +

      P1.04-095 - Integrin a11b1 Regulates Cancer Stromal Stiffness and Promotes Tumorigenicity and Metastasis in Non-Small Cell Lung Cancer (ID 3084)

      09:30 - 17:00  |  Author(s): R. Navab

      • Abstract
      • Slides

      Background:
      Integrin α11β1 is a stromal cell-specific receptor for fibrillar collagens and is over-expressed in carcinoma-associated fibroblasts (CAFs) in non- small cell lung cancer (NSCLC). We have studied the direct role of stromal integrin a11 on the growth and metastasis of NSCLC cells using novel immune-compromised a11 deficient mice.

      Methods:
      We developed α11 non-expressing immune-deficient mice by back-crossing for at least 10 times the α11-deficient heterozygous C57BL/6J mice (+/-) to obtain a homogenous C57BL/6 background. These were subsequently bred with the BALB/c SCID mice for 7 generations, producing α11-deficient heterozygous (+/-) in SCID background. In vivo studies were done using subcutaneous tumorigenicity assay and orthotopic model to evaluate metastatic potential of integrin α11. Immunostaining were carried out using integrin α11, α-SMA, and cytokeratin. PisroSirius red staining was used to visualize the collagen fibers. Images were taken by polarized-light microscopy using parallel and perpendicular polarizer orientations on an Olympus BX51 microscope. Second Harmonic Generation (SHG) was used to visualize fibrillar collagen and atomic force microscopy was applied to measure the stiffness in tumor stroma.

      Results:
      The tumor growth of both primary human lung cancer (PHLC) and established NSCLC cells in α11 knockout (α11[-/-]) mice was significantly impeded compared to wild type (α11[+/+]). Orthotopic implantation of a spontaneously metastatic NCI-H460SM cell line into the lungs of α11[-/-] and α11[+/+] mice showed significant reduction in the metastatic potential of these cells in the α11[-/-] mice. Using mouse WG-6v2 Illumina Bead Chips, we identified that alpha11 expression correlates with that of a fibrillar collagen cross-linking enzyme, LOXL1, in the xenograft stroma. Fibrillar collagen was highly disorganized and had a significantly lower elastic modulus in the alpha11 knockout xenografts compared to wildtype. The results suggest a role for α11 in promoting tumor growth and metastatic progression by affecting the collagen stiffness of the tumor stroma.

      Conclusion:
      The integrin a11β1 signaling pathway in CAFs promotes tumor growth and metastasis of NSCLC cells. This appears closely linked to collagen cross-linking, the organization, and stiffness of fibrillar collagen matrices.

      Only Active Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login or select "Add to Cart" and proceed to checkout.