media posted on 2023-03-31, 02:00 authored by Antoun Al Absi, Hannah Wurzer, Coralie Guerin, Celine Hoffmann, Flora Moreau, Xianqing Mao, Joshua Brown-Clay, Rémi Petrolli, Carla Pou Casellas, Monika Dieterle, Jean-Paul Thiery, Salem Chouaib, Guy Berchem, Bassam Janji, Clément Thomas
Typical actin cytoskeleton organization observed in most NK cell-conjugated MDA-MB-231 cells. The cell conjugate was acquired on a LSM880 laser scanning confocal microscope (Carl Zeiss) with Airyscan in the high-resolution mode, and the 3D projection was assembled and animated using Zeiss Zen Software. Then NK cell was stained in red (PKH26) whereas the LifeAct-mEGFP-expressing tumour cell appears in green.
National Research Fund (FNR), Luxembourg
ARTICLE ABSTRACTElucidation of the underlying molecular mechanisms of immune evasion in cancer is critical for the development of immunotherapies aimed to restore and stimulate effective antitumor immunity. Here, we evaluate the role of the actin cytoskeleton in breast cancer cell resistance to cytotoxic natural killer (NK) cells. A significant fraction of breast cancer cells responded to NK-cell attack via a surprisingly rapid and massive accumulation of F-actin near the immunologic synapse, a process we termed “actin response.” Live-cell imaging provided direct evidence that the actin response is associated with tumor cell resistance to NK-cell–mediated cell death. High-throughput imaging flow cytometry analyses showed that breast cancer cell lines highly resistant to NK cells were significantly enriched in actin response-competent cells as compared with susceptible cell lines. The actin response was not associated with a defect in NK-cell activation but correlated with reduced intracellular levels of the cytotoxic protease granzyme B and a lower rate of apoptosis in target cells. Inhibition of the actin response by knocking down CDC42 or N-WASP led to a significant increase in granzyme B levels in target cells and was sufficient to convert resistant breast cancer cell lines into a highly susceptible phenotype. The actin response and its protective effects were fully recapitulated using donor-derived primary NK cells as effector cells. Together, these findings establish the pivotal role of actin remodeling in breast cancer cell resistance to NK-cell–mediated killing.Significance: These findings establish the pivotal role of the actin cytoskeleton in driving breast cancer cell resistance to natural killer cells, a subset of cytotoxic lymphocytes with important roles in innate antitumor immunity. Cancer Res; 78(19); 5631–43. ©2018 AACR.