• Media type: E-Article
  • Title: BSCI-08. In vivo two-photon characterization of tumor-associated macrophages and microglia (TAM/M) and CX3CR1 during different steps of brain metastasis formation from lung cancer
  • Contributor: Zhang, Wenlong; Karschnia, Philipp; von Mücke-Heim, Iven-Alex; Mulazzani, Matthias; Zhou, Xiolan; Xu, Tao; Blobner, Jens; Teske, Nico; Langer, Sigrid; Thon, Niklas; Ishikawa-Ankerhold, Hellen; Straube, Andreas; Tonn, Joerg-Christian; von Baumgarten, Louisa
  • imprint: Oxford University Press (OUP), 2021
  • Published in: Neuro-Oncology Advances
  • Language: English
  • DOI: 10.1093/noajnl/vdab071.007
  • ISSN: 2632-2498
  • Keywords: General Medicine
  • Origination:
  • Footnote:
  • Description: <jats:title>Abstract</jats:title> <jats:sec> <jats:title>Background</jats:title> <jats:p>Brain metastases represent a common complication of lung cancer and dramatically limit prognosis in affected patients. The influence of tumor-associated macrophages and microglia (TAM/M) and their receptor CX3CR1 on different steps of brain metastasis formation from lung cancer is poorly characterized, but might be of therapeutic relevance.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>We established an orthotopic cerebral metastasis model using CX3CR1-proficient (CX3CR1GFP/wt) and -deficient (CX3CR1GFP/GFP) mice with green-fluorescent TAM/M. A cranial window was prepared, and intracarotid injection of red-fluorescent Lewis Lung Carcinoma-cells (tdtLLC) was performed two weeks later. Formation of brain metastases was followed by repetitive two-photon laser scanning microscopy.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>After intracarotid injection, intravascular tumor cells extravasated into the cerebral parenchyma and eventually formed micrometastases (≤50 cells) and mature macrometastases (&amp;gt;50 cells). We observed phagocytosis of extravasated tumor cells by TAM/M during early steps of metastatic growth. Notably, these anti-tumor effects of TAM/M diminished during later steps of metastasis formation and were accompanied by TAM/M accumulation and activation. CX3CR1-deficiency resulted in a lower number of extravasated tumor cells, and only a small number of TAM/M were visualized during early steps of metastasis formation (extravasation, formation of micrometastases) in such mice. In contrast, progression of extravasated tumor cells into micrometastases was more frequently found in CX3CR1-deficient mice. Overall, these mechanisms resulted in a comparable number of mature macrometastases between CX3CR1-deficient and -proficient mice.</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusion</jats:title> <jats:p>Our findings indicate that unspecific inhibition of CX3CR1 might not be a suitable therapeutic approach to prevent cerebral dissemination of lung cancer cells. Given the close interaction between TAM/M and tumour cells during metastasis formation, other therapeutic approaches targeting TAM/M function warrant evaluation. Such concepts might be evaluated in vivo using the herein established orthotopic mouse model.</jats:p> </jats:sec>
  • Access State: Open Access