Sorting Cancer-Associated Fibroblasts (CAFs)

Featuring Our Colorectal CAFS
CAFs play a central role in the Tumor Microenvironment (TME). The TME has been identified as one of the driving factors of tumor progression and invasion. Inside this microenvironment, CAFs, a type of perpetually activated fibroblasts, have been implicated to have a strong tumor modulating effect and play a key role in areas such as drug resistance.

This makes CAFs a target for cancer therapies. The challenge is the TME is heterogeneous making it a challenge to derive homogeneously relevant populations for basic research and drug discovery. This new study uses our Colorectal CAFs to identify markers for isolating these populations. Martin Nurmik, Pit Ullmann, Fabien Rodriguez, Serge Haan, Elisabeth Letellier. In search of definitions: Cancer-associated fibroblasts and their markers. doi: 10.1002/ijc.32193.

Images: Expression of common markers in patient-derived fibroblasts. Immunofluorescent staining of primary colon cancer fibroblasts (Neuromics, #CAF05), reveals a heterogeneous expression pattern for both αSMA/ACTA2 (abcam #ab7817, 1/200) and FAP (Santa-Cruz Biotechnology #sc-65398, 1/200), while PDGFRα (abcam #ab61219, 1/200) expression in tested cells remains relatively homogenous. Nuclei of fibroblasts were stained using DAPI (DAPI Fluoromount-G® Mounting Medium). Image is representative of three independent biological experiments.Cells were imaged using a Zeiss LSM 510 Meta laser scanning confocal microscope (Carl Zeiss, Jena, Germany) with a Plan-Apochromat 63x/1.40.

The authors conclude when selecting for CAF populations using antibody-based methods such as FACS, it is essential that multiple surface markers are used in order to avoid any chance of introducing unintentional subtype bias. Other available surface markers such as PDGFRα/β work well here, as do more general fibroblast surface markers like Thy-1 cell surface antigen (CD90), provided that the cell population is also subjected to selection with negative markers,