Lung Cancer Induces NK Cell Contractility and Cytotoxicity Through Transcription Factor Nuclear Localization

Abstract

Actomyosin-mediated cellular contractility is highly conserved for mechanotransduction and signalling. While this phenomenon has been observed in adherent cell models, whether/how contractile forces regulate the function of suspension cells like natural killer (NK) cells during cancer surveillance, is unknown. Here, we demonstrated in coculture settings that the evolutionarily conserved NK cell transcription factor, Eomes, undergoes nuclear shuttling during lung cancer cell surveillance. Biophysical and biochemical analyses revealed mechanistic enhancement of NK cell actomyosin-mediated contractility, which is associated with nuclear flattening, thus enabling nuclear entry of Eomes associated with enhanced NK cytotoxicity. We found that NK cells responded to the presumed immunosuppressive TGFβ in the NK-lung cancer coculture medium to sustain its intracellular contractility through myosin light chain phosphorylation, thereby promoting Eomes nuclear localization. Therefore, our results demonstrate that lung cancer cells provoke NK cell contractility as an early phase activation mechanism and that Eomes is a plausible mechano-responsive protein for increased NK cytotoxicity. There is scope for strategic application of actomyosin-mediated contractility modulating drugs ex vivo, to reinvigorate NK cells prior to adoptive cancer immunotherapy in vivo (177 words).

Natural Killer cell contractility and cytotoxicity is driven by TLR3 agonist-mediated TAZ cytoplasmic sequestration

“…The copyright holder for this this version posted January 19, 2023. ; https://doi.org/10.1101/2023.01.18.524654 doi: bioRxiv preprint perpetuate stained cells for as long as 6 days as determined previously [1] , except for those used for cytotoxicity assay against model target cell line, K562. Lung and breast cancer cells were pre-seeded for at least eight hours for them to attach to cell culture plate.…”

“…The effector (NK-92 or hNK) to target (cancer cells) were cocultured in a ratio of 2.5:1 as previously determined [1] [83] . Briefly, hNK and NK-92 cells were pre-stained with CFSE (Sigma) according to the manufacturer's protocol, which was able to preprint (which was not certified by peer review) is the author/funder.…”

“…The innate immune Natural Killer (NK) cells are indispensable in defending against infection and cancer [1]- [4] . Of particular interest is the integration of intrinsic and extrinsic cell and molecular, biochemical and biophysical signals, which activate dormant transcriptional networks responsible for NK cytotoxicity through various pattern recognition receptors (PRRs), for example, Toll-like receptors (TLRs) 1-9 in humans [5]- [8] .…”

“…Importantly, what are the extrinsic and intrinsic triggers that modulate NK cell activity to reinvigorate it for immunotherapy? We have recently identified intracellular contractility in NK cells which upregulates NK cytotoxicity by promoting nuclear localisation of transcription factor, Eomes [1] . Other studies also suggested that NK cells respond to mechanical forces [11] , indicating that increased substrate stiffness enhances NK cell cytotoxicity [12] [13] .…”

“…The copyright holder for this this version posted January 19, 2023. ; https://doi.org/10.1101/2023.01. 18.524654 doi: bioRxiv preprint responses against cancer cells [1] . Furthermore, biochemical and biophysical signals should be integrated to regulate pathophysiological activities.…”