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Internalization and trafficking of PD‐L1 in MDAMB231 breast cancer cells
Author(s) -
Rudkouskaya Alena,
Barroso Margarida
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.809.7
Subject(s) - endosome , endocytic cycle , internalization , transferrin receptor , chemistry , cancer research , cancer cell , cancer , transferrin , immunotherapy , breast cancer , monoclonal antibody , endocytosis , antibody , medicine , cell , immunology , biochemistry
Immunotherapy has emerged as a very promising type of cancer treatment. However, despite successful clinical use of several monoclonal antibodies developed to target immune checkpoint inhibitors present in tumor cells or tumor‐infiltrating lymphocytes, there is very little known about their endocytic pathway in cancer cells. To elucidate this process we studied programmed cell death‐ligand 1 (PD‐L1) uptake in MDAMB231 breast cancer cells using both live imaging and immunofluorescent staining of fixed cells. We found that five minute pulse with 10 ug/mL PD‐L1 AF488 and transferrin‐AF555 (Tf‐AF555), followed by wash and live imaging, results in significant accumulation of PD‐L1 both at the plasma membrane and in the endosomes often also containing Tf‐transferrin receptor complexes (Tf‐TfR). To further investigate PD‐L1 trafficking, we performed one hour uptake of both PD‐L1AF555 and Tf‐AF647, fixed the cells and stained with Early Endosome Antigen1 (EEA1). Airyscan imaging of these cells showed that many large vesicles, characteristic to MDAMB231 cells, are positive for all three markers suggesting again that even at late stages PD‐L1 is trafficking along the endocytic pathway with Tf‐TfR complexes. These findings may help to develop non‐invasive quantitative imaging approach to monitor the spatial distribution and accumulation of PD‐L1 in the tumor xenografts in preclinical studies to advance cancer immunotherapy. Support or Funding Information This work was funded by NIH grant R01 EB019443.