Effect of Hypoxia on Siglec-7 and Siglec-9 Receptors and Sialoglycan Ligands and Impact of Their Targeting on NK Cell Cytotoxicity
Background/Objectives: Tumor microenvironmental hypoxia is an established hallmark of solid tumors. It significantly contributes to tumor aggressiveness and therapy resistance and has been reported to affect the balance of activating/inhibitory surface receptors’ expression and activity on NK cells....
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2024-10-01
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| author | Husam Nawafleh Nagwa Zeinelabdin Michelle K. Greene Anitha Krishnan Linus Ho Mohamed Genead Derek Kunimoto Christopher J. Scott Michael Tolentino Salem Chouaib |
| author_facet | Husam Nawafleh Nagwa Zeinelabdin Michelle K. Greene Anitha Krishnan Linus Ho Mohamed Genead Derek Kunimoto Christopher J. Scott Michael Tolentino Salem Chouaib |
| author_sort | Husam Nawafleh |
| collection | DOAJ |
| description | Background/Objectives: Tumor microenvironmental hypoxia is an established hallmark of solid tumors. It significantly contributes to tumor aggressiveness and therapy resistance and has been reported to affect the balance of activating/inhibitory surface receptors’ expression and activity on NK cells. In the current study, we investigated the impact of hypoxia on the surface expression of Siglec-7 and Siglec-9 (Sig-7/9) and their ligands in NK cells and tumor target cells. The functional consequence of Siglec blockage using nanoparticles specifically designed to target and block Sig-7/9 receptors on NK cell cytotoxicity was elucidated. Methods: CD56⁺ CD3<sup>−</sup> NK cells were isolated from PBMCs along with an NK-92 clone and used as effector cells, while MCF-7 and K562 served as target cells. All cells were incubated under normoxic or hypoxic conditions for 24 h. To assess Siglec-7 and Siglec-9 receptor expression, U937, NK-92, and primary NK cells were stained with PE-labeled antibodies against CD328 Siglec-7/9. Interactions between Siglec-7/9 and their sialylated ligands, along with their functional impact on NK cell activity, were evaluated using polymeric nanoparticles coated with a sialic acid mimetic. Immunological synapse formation and live-cell imaging were performed with a ZEISS LSM 800 with Airyscan at 10× magnification for 24 h. Results: Our data indicate that hypoxia had no effect on the expression of Siglec-7/9 receptors by NK cells. In contrast, hypoxic stress resulted in an increase in Siglec-7 sialoglycan ligand expression by a sub-population of NK target cells. Using polymeric nanoparticles coated with a sialic acid mimetic that binds both Siglec-7 and -9 (Sig-7/9 NP), we demonstrated that incubation of these nanoparticles with NK cells resulted in increased immunological synapse formation, granzyme B accumulation, and killing of NK target cells. These studies indicate that hypoxic stress may have an impact on NK cell-based therapies and highlight the need to consider the hypoxic microenvironment for tumor-specific glycosylation. Conclusions: Our findings point to the role of Siglec–sialylated glycan interactions in hypoxic stress-induced NK cell dysfunction and recommend the potential integration of the manipulation of this axis through the targeting of Siglecs in future cancer immunotherapy strategies. |
| format | Article |
| id | doaj-art-e61f4f95b27848a79d58cce201dd6447 |
| institution | DOAJ |
| issn | 1424-8247 |
| language | English |
| publishDate | 2024-10-01 |
| publisher | MDPI AG |
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| spelling | doaj-art-e61f4f95b27848a79d58cce201dd64472025-08-20T02:48:07ZengMDPI AGPharmaceuticals1424-82472024-10-011711144310.3390/ph17111443Effect of Hypoxia on Siglec-7 and Siglec-9 Receptors and Sialoglycan Ligands and Impact of Their Targeting on NK Cell CytotoxicityHusam Nawafleh0Nagwa Zeinelabdin1Michelle K. Greene2Anitha Krishnan3Linus Ho4Mohamed Genead5Derek Kunimoto6Christopher J. Scott7Michael Tolentino8Salem Chouaib9Thumbay Research Institute for Precision Medicine, Gulf Medical University, Ajman 4184, United Arab EmiratesThumbay Research Institute for Precision Medicine, Gulf Medical University, Ajman 4184, United Arab EmiratesAviceda Glycotech, 97 Lisburn Road, Belfast BT9 7AE, UKAviceda Therapeutics Inc., Cambridge, MA 02142, USAAviceda Therapeutics Inc., Cambridge, MA 02142, USAAviceda Therapeutics Inc., Cambridge, MA 02142, USAAviceda Therapeutics Inc., Cambridge, MA 02142, USAAviceda Glycotech, 97 Lisburn Road, Belfast BT9 7AE, UKAviceda Therapeutics Inc., Cambridge, MA 02142, USAThumbay Research Institute for Precision Medicine, Gulf Medical University, Ajman 4184, United Arab EmiratesBackground/Objectives: Tumor microenvironmental hypoxia is an established hallmark of solid tumors. It significantly contributes to tumor aggressiveness and therapy resistance and has been reported to affect the balance of activating/inhibitory surface receptors’ expression and activity on NK cells. In the current study, we investigated the impact of hypoxia on the surface expression of Siglec-7 and Siglec-9 (Sig-7/9) and their ligands in NK cells and tumor target cells. The functional consequence of Siglec blockage using nanoparticles specifically designed to target and block Sig-7/9 receptors on NK cell cytotoxicity was elucidated. Methods: CD56⁺ CD3<sup>−</sup> NK cells were isolated from PBMCs along with an NK-92 clone and used as effector cells, while MCF-7 and K562 served as target cells. All cells were incubated under normoxic or hypoxic conditions for 24 h. To assess Siglec-7 and Siglec-9 receptor expression, U937, NK-92, and primary NK cells were stained with PE-labeled antibodies against CD328 Siglec-7/9. Interactions between Siglec-7/9 and their sialylated ligands, along with their functional impact on NK cell activity, were evaluated using polymeric nanoparticles coated with a sialic acid mimetic. Immunological synapse formation and live-cell imaging were performed with a ZEISS LSM 800 with Airyscan at 10× magnification for 24 h. Results: Our data indicate that hypoxia had no effect on the expression of Siglec-7/9 receptors by NK cells. In contrast, hypoxic stress resulted in an increase in Siglec-7 sialoglycan ligand expression by a sub-population of NK target cells. Using polymeric nanoparticles coated with a sialic acid mimetic that binds both Siglec-7 and -9 (Sig-7/9 NP), we demonstrated that incubation of these nanoparticles with NK cells resulted in increased immunological synapse formation, granzyme B accumulation, and killing of NK target cells. These studies indicate that hypoxic stress may have an impact on NK cell-based therapies and highlight the need to consider the hypoxic microenvironment for tumor-specific glycosylation. Conclusions: Our findings point to the role of Siglec–sialylated glycan interactions in hypoxic stress-induced NK cell dysfunction and recommend the potential integration of the manipulation of this axis through the targeting of Siglecs in future cancer immunotherapy strategies.https://www.mdpi.com/1424-8247/17/11/1443siglec receptorssialoglycan ligandshypoxiaNK cellsnanoparticlesimmune synapses |
| spellingShingle | Husam Nawafleh Nagwa Zeinelabdin Michelle K. Greene Anitha Krishnan Linus Ho Mohamed Genead Derek Kunimoto Christopher J. Scott Michael Tolentino Salem Chouaib Effect of Hypoxia on Siglec-7 and Siglec-9 Receptors and Sialoglycan Ligands and Impact of Their Targeting on NK Cell Cytotoxicity Pharmaceuticals siglec receptors sialoglycan ligands hypoxia NK cells nanoparticles immune synapses |
| title | Effect of Hypoxia on Siglec-7 and Siglec-9 Receptors and Sialoglycan Ligands and Impact of Their Targeting on NK Cell Cytotoxicity |
| title_full | Effect of Hypoxia on Siglec-7 and Siglec-9 Receptors and Sialoglycan Ligands and Impact of Their Targeting on NK Cell Cytotoxicity |
| title_fullStr | Effect of Hypoxia on Siglec-7 and Siglec-9 Receptors and Sialoglycan Ligands and Impact of Their Targeting on NK Cell Cytotoxicity |
| title_full_unstemmed | Effect of Hypoxia on Siglec-7 and Siglec-9 Receptors and Sialoglycan Ligands and Impact of Their Targeting on NK Cell Cytotoxicity |
| title_short | Effect of Hypoxia on Siglec-7 and Siglec-9 Receptors and Sialoglycan Ligands and Impact of Their Targeting on NK Cell Cytotoxicity |
| title_sort | effect of hypoxia on siglec 7 and siglec 9 receptors and sialoglycan ligands and impact of their targeting on nk cell cytotoxicity |
| topic | siglec receptors sialoglycan ligands hypoxia NK cells nanoparticles immune synapses |
| url | https://www.mdpi.com/1424-8247/17/11/1443 |
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