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  P3.01 - Poster Session 3 - Cancer Biology (ID 147)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Biology
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/30/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

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    P3.01-003 - Identification and Tumorigenic Role of Mesenchymal Stem Cells from Human Lung Cancer (ID 3245)

    09:30 - 09:30  |  Author(s): M. Rusca
    • Abstract

    Background
    A hierarchical model in which a small population of stem cells or Cancer Initiating Cells (CIC) may be responsible of tumour growth has been proposed. CIC is defined as a cell able to regenerate detectable neoplastic populations in xenografted immunodeficient mice. By this experimental approach, convincing data have led to the identification of CIC in solid tumours including breast, brain, colorectal, melanoma and lung. However, the autonomous growth ability of CIC is allowed in specialized structures, called niches, in which a microenvironmental control is exerted by several stromal elements including mesenchymal cells. These attractive pathogenetic mechanisms encompass innovative therapeutic implications because the limited success of the actual treatment of lung cancer may be attributable to the lack of targeting on CICs and their niches. The aim of the present study was to identify mesenchymal stem cells (MSC) from Non Small Cell Lung Cancer (NSCLC) and to investigate their biological properties and in vivo tumorigenic potential.

    Methods
    Small fragments of NSCLC (53 Adeno- and 24 Squamous carcinoma) surgically removed from 77 patients (46 male) were subjected to enzymatic digestion whereas most of the original sample was processed for diagnostic purpose. To identify mesenchymal cells from human lung cancer (hLc-MSC) we used different conditioning media and immunomagnetic selection to separate neoplastic epithelial cells frequently growing together with adherent stromal cells at early passages. To determine their tumorigenic properties, female immunodeficient BALB/c nude mice were subcutaneously injected with either 10[6] hLc-MSCs (from male donors) alone or in combination with 10[6] Calu-3, a human adenocarcinoma cell line lacking Y chromosome and able to reproducibly induce xenografted tumours.

    Results
    We have been able to obtain stable primary cultures of hLc-MSC, expandable for at least 14 passages, from 62% of NSCLC samples. This cell population uniformly expressed the typical MSC markers CD90, CD105, CD73, CD13 and CD44 at FACS analysis. hLc-MSC were negative for EpCAM, CD45, CD14 and CD34 whereas CD117 and CD133 were expressed at low frequency. Clones and subclones were documented by limiting dilution analysis. The nuclear expression of transcription factors involved in stemness (OCT 3/4 and SOX2), and in bronchio-alveolar (TTF1) or squamous (p63) lineage commitment was consistently present in hLc-MSC isolated from Adeno- or Squamous cell carcinomas. In vivo xenotransplantation demonstrated that although hLc-MSC administered alone did not generate tumours, their co-injection with Calu-3 developed in all animals subcutaneous nodules that were 10-fold larger than those induced by equal doses of Calu-3 injected alone. To detect the fate of both injected cells on sections of xenografted tumours, FISH analysis of human specific sex chromosomes was combined with immunohistochemistry. We documented that cytokeratin positive adenocarcinoma structures showing X chromosomes only (Calu-3 derived) were surrounded by a thin layer of non neoplastic cells carrying XY chromosomes (hLc-MSC derived). The cross talk and phenotypic changes of E-Cadherin positive neoplastic cells co-cultured with hLc-MSC were also documented.

    Conclusion
    Our study demonstrates that the reciprocal inductive interactions between the mesenchyme and the neoplastic epithelium are essential for the fate induction of lung cancer.