Immunomagnetic isolation of circulating melanoma cells and detection of PD-L1 status.
Joseph W PoYafeng MaBavanthi BalakrishnaDaniel BrungsFarhad AzimiPaul de SouzaTherese Maria BeckerPublished in: PloS one (2019)
Personalised medicine targeted to specific biomarkers such as BRAF and c-Kit has radically improved the success of melanoma therapy. More recently, further advances have been made using therapies targeting the immune response. In particular, therapies targeting the PD-1/PD-L1 or CTLA-4 axes alone or in combination have shown more sustained responses in 30-60% of patients. However, these therapies are associated with considerable toxicities and useful biomarkers to predict responders and non-responders are slow to emerge. Here we developed a reliable melanoma circulating tumor cell (CTC) detection method with PD-L1 evaluation on CTCs. A set of melanoma cell surface markers was tested as candidates for targeted melanoma CTC isolation and a melanoma specific immunostaining-based CTC identification protocol combined with PD-L1 detection was established. In vitro testing of the effect of exposure to blood cells on melanoma cell PD-L1 expression was undertaken. Immunomagnetic targeting isolated melanoma CTCs in up to 87.5% of stage IV melanoma patient blood samples and 3 8.6% of these had some PD-L1 expressing CTCs. Our in vitro data demonstrate PD-L1 induction on melanoma cells in the blood.This study established a robust, reliable method to isolate melanoma CTCs and detect expression of PD-L1 on these cells.
Keyphrases
- circulating tumor cells
- skin cancer
- circulating tumor
- immune response
- cancer therapy
- induced apoptosis
- basal cell carcinoma
- end stage renal disease
- drug delivery
- single cell
- cell therapy
- cell cycle arrest
- newly diagnosed
- ejection fraction
- peritoneal dialysis
- chronic kidney disease
- dendritic cells
- endoplasmic reticulum stress
- electronic health record
- deep learning