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The surface receptor CD8[alpha] is present on 20%-80% of human (but not mouse) NK cells, yet its function on NK cells remains poorly understood. CD8[alpha] expression on donor NK cells was associated with a lack of therapeutic responses in patients with leukemia in prior studies, thus, we hypothesized that CD8[alpha] may affect critical NK cell functions. Here, we discovered that CD8[[alpha].sup.-] NK cells had improved control of leukemia in xenograft models compared with CD8[[alpha].sup.+] NK cells, likely due to an enhanced capacity for proliferation. Unexpectedly, we found that CD8[alpha] expression was induced on approximately 30% of previously CD8[[alpha].sup.- ] NK cells following IL-15 stimulation. These induced CD8[[alpha].sup.+] (iCD8[[alpha].sup.+]) NK cells had the greatest proliferation, responses to IL-15 signaling, and metabolic activity compared with those that sustained existing CD8[alpha] expression (sustained CD8[[alpha].sup.+]) or those that remained CD8[[alpha].sup.-] (persistent CD8[alpha]). These iCD8[[alpha].sup.+] cells originated from an IL- 15R[[beta].sup.hi] NK cell population, with CD8[alpha] expression dependent on the transcription factor RUNX3. Moreover, CD8A CRISPR/Cas9 deletion resulted in enhanced responses through the activating receptor NKp30, possibly by modulating KIR inhibitory function. Thus, CD8[alpha] status identified human NK cell capacity for IL-15-induced proliferation and metabolism in a time-dependent fashion, and its presence had a suppressive effect on NK cell-activating receptors., Introduction NK cells are innate lymphoid cells that protect the host from infection and malignant transformation through direct cytotoxicity and communication via cytokine and chemokine production (1-3). Human NK cells [...]

Metastatic (m) colorectal cancer (CRC) is an incurable disease with a poor prognosis and thus remains an unmet clinical need. Immune checkpoint blockade (ICB)-based immunotherapy is effective for mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) mCRC patients, but it does not benefit the majority of mCRC patients. NK cells are innate lymphoid cells with potent effector responses against a variety of tumor cells but are frequently dysfunctional in cancer patients. Memory-like (ML) NK cells differentiated after IL-12/IL-15/IL-18 activation overcome many challenges to effective NK cell anti-tumor responses, exhibiting enhanced recognition, function, and in vivo persistence. We hypothesized that ML differentiation enhances the NK cell responses to CRC. Compared to conventional (c) NK cells, ML NK cells displayed increased IFN-γ production against both CRC cell lines and primary patient-derived CRC spheroids. ML NK cells also exhibited improved killing of CRC target cells in vitro in short-term and sustained cytotoxicity assays, as well as in vivo in NSG mice. Mechanistically, enhanced ML NK cell responses were dependent on the activating receptor NKG2D as its blockade significantly decreased ML NK cell functions. Compared to cNK cells, ML NK cells exhibited greater antibody-dependent cytotoxicity when targeted against CRC by cetuximab. ML NK cells from healthy donors and mCRC patients exhibited increased anti-CRC responses. Collectively, our findings demonstrate that ML NK cells exhibit enhanced responses against CRC targets, warranting further investigation in clinical trials for mCRC patients, including those who have failed ICB. [ABSTRACT FROM AUTHOR]

Accumulation of senescent cells (SNCs) with a senescence‐associated secretory phenotype (SASP) has been implicated as a major source of chronic sterile inflammation leading to many age‐related pathologies. Herein, we provide evidence that a bifunctional immunotherapeutic, HCW9218, with capabilities of neutralizing TGF‐β and stimulating immune cells, can be safely administered systemically to reduce SNCs and alleviate SASP in mice. In the diabetic db/db mouse model, subcutaneous administration of HCW9218 reduced senescent islet β cells and SASP resulting in improved glucose tolerance, insulin resistance, and aging index. In naturally aged mice, subcutaneous administration of HCW9218 durably reduced the level of SNCs and SASP, leading to lower expression of pro‐inflammatory genes in peripheral organs. HCW9218 treatment also reverted the pattern of key regulatory circadian gene expression in aged mice to levels observed in young mice and impacted genes associated with metabolism and fibrosis in the liver. Single‐nucleus RNA Sequencing analysis further revealed that HCW9218 treatment differentially changed the transcriptomic landscape of hepatocyte subtypes involving metabolic, signaling, cell‐cycle, and senescence‐associated pathways in naturally aged mice. Long‐term survival studies also showed that HCW9218 treatment improved physical performance without compromising the health span of naturally aged mice. Thus, HCW9218 represents a novel immunotherapeutic approach and a clinically promising new class of senotherapeutic agents targeting cellular senescence‐associated diseases. [ABSTRACT FROM AUTHOR]