Pancreatic ductal adenocarcinoma (PDAC) presents a formidable challenge in oncology due to its aggressive progression, propensity for early metastasis, and resistance to conventional therapies. The development of effective and less toxic treatments is crucial for improving the prognosis of PDAC. We aimed to investigate the synergistic antitumor potential of modified FOLFIRINOX (mFOLFIRINOX) combined with natural killer (NK) cell therapy in PDAC models.
We evaluated changes in NK-cell-activating ligands and apoptosis-inducing receptor expression after mFOLFIRINOX treatment both in vitro and in vivo. Subsequently, NK cells were administered to mFOLFIRINOX-pre-treated PDAC cells to assess NK cell cytotoxicity, immune responses, and tumor progression both in vitro and in vivo mouse models.
Treatment with mFOLFIRINOX led to the significant upregulation of NK-cell-activating ligands and apoptosis-inducing receptors across the PDAC cell lines and tumor cells collected in vivo, thereby enhancing their susceptibility to NK-cell-mediated cytotoxicity. In comparison with either treatment alone, mFOLFIRINOX and NK cell combination therapy resulted in enhanced cytolysis in all cell lines. In vivo studies demonstrated that combination therapy substantially inhibited tumor growth and prolonged survival in a mouse model.
mFOLFIRINOX combined with NK cell therapy demonstrates enhanced antitumor activity against PDAC, potentially improving clinical outcomes. These findings highlight the need for continued research to optimize this combination strategy for clinical utility.

Clinical application of autologous chimeric antigen receptor (CAR)-T cells is complicated by limited targeting of cancer types, as well as the time-consuming and costly manufacturing process. We develop CD70-targeted, induced pluripotent stem cell-derived CAR-natural killer (NK) (70CAR-iNK) cells as an approach for universal immune cell therapy. Besides the CD70-targeted CAR molecule, 70CAR-iNK cells are modified with CD70 gene knockout, a high-affinity non-cleavable CD16 (hnCD16), and an interleukin (IL)-15 receptor α/IL-15 fusion protein (IL15RF). Multi-gene-edited 70CAR-iNK cells exhibit robust cytotoxicity against a wide range of tumors. In vivo xenograft models further demonstrate their potency in effectively targeting lymphoma and renal cancers. Furthermore, we find that recipient alloreactive T cells express high levels of CD70 and can be eliminated by 70CAR-iNK cells, leading to improved survival and persistence of iNK cells. With the capability of tumor targeting and the potential to eliminate alloreactive T cells, 70CAR-iNK cells are potent candidates for next-generation universal immune cell therapy.
Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer. Transforming growth factor beta (TGF-β) is highly expressed in the liver tumor microenvironment and is known to inhibit immune cell activity. Here, we used human induced pluripotent stem cells (iPSCs) to produce natural killer (NK) cells engineered to mediate improved anti-HCC activity. Specifically, we produced iPSC-NK cells with either knockout TGF-β receptor 2 (TGFBR2-KO) or expression of a dominant negative (DN) form of the TGF-β receptor 2 (TGFBR2-DN) combined with chimeric antigen receptors (CARs) that target either GPC3 or AFP. The TGFBR2-KO and TGFBR2-DN iPSC-NK cells are resistant to TGF-β inhibition and improved anti-HCC activity. However, expression of anti-HCC CARs on iPSC-NK cells did not lead to effective anti-HCC activity unless there was also inhibition of TGF-β activity. Our findings demonstrate that TGF-β signaling blockade is required for effective NK cell function against HCC and potentially other malignancies that express high levels of TGF-β.
Copyright © 2024 Elsevier Inc. All rights reserved.

The natural killer (NK) cell function of patients with malignant tumours may be suppressed by deficiency, and the poor prognosis of renal cell carcinoma (RCC) patients may be due to escape from NK cell cytotoxicity, especially with respect to natural cytotoxicity receptors (NCRs) on the NK cell surface. However, the specific mechanism remains unclear. Therefore, in this study, we sought to explore the role of NCR, especially NCR3 splice variants, in the process of NK cell deficiency in RCC patients.
We used flow cytometry to analyse the phenotype of NK cells from the peripheral blood and kidney tumour tissue of RCC patients. The NKp30-mediated NK cell killing function was measured by antibody-dependent cell-mediated cytotoxicity (ADCC) in NK and RCC cell coincubation. We extracted RNA from the peripheral blood mononuclear cells (PBMCs) of RCC patients and renal carcinoma tissue and carried out real-time quantitative PCR to detect the mRNA levels of NKp30a, NKp30b and NKp30c. mRNA expression levels of cytokines (IL-6, IL-8, IL-10, IL-18 and TGF-β) based on RNA extracted from renal carcinoma tissue and adjacent normal kidney tissues were also measured by real-time quantitative PCR.
Regarding the phenotype of NK cells in RCC patients, the proportion of NK cells in tumour tissue was significantly reduced, with changes in the NK cell proportion being most obvious in NKp30+ NK cells. Furthermore, the results of the ADCC function assay showed limited NKp30+ NK cell-mediated cytotoxicity in RCC patients. Through real-time quantitative PCR, we found lower expression of NKp30a and NKp30b, the immunostimulatory splice variants of NCR3 encoding NKp30, in RCC patients. Moreover, expression of activating cytokines (IL-6 and IL-8) in renal cancer tissue was decreased, though inhibitory cytokine (TGF-β) expression remained unchanged, which may result in an immunosuppressive cytokine microenvironment.
Decreased expression of immunostimulatory NCR3 splice variants and the inhibitory cytokine microenvironment in RCC patients may contribute to deficient NK cell cytotoxicity and renal carcinoma cell immune escape from NK cell killing, which may provide a theoretical basis for finding new immunotherapeutic targets for RCC.
Copyright © 2024, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Recent studies have characterized various mouse antigen-presenting cells (APCs) expressing the lymphoid-lineage transcription factor RORγt (Retinoid-related orphan receptor gamma t), which exhibit distinct phenotypic features and are implicated in the induction of peripheral regulatory T cells (Tregs) and immune tolerance to microbiota and self-antigens. These APCs encompass Janus cells and Thetis cell subsets, some of which express the AutoImmune REgulator (AIRE). RORγt+ MHCII+ type 3 innate lymphoid cells (ILC3) have also been implicated in the instruction of microbiota-specific Tregs. While RORγt+ APCs have been actively investigated in mice, the identity and function of these cell subsets in humans remain elusive. Herein, we identify a rare subset of RORγt+ cells with dendritic cell (DC) features through integrated single-cell RNA sequencing and single-cell ATAC sequencing. These cells, which we term RORγt+ DC-like cells (R-DC-like), exhibit DC morphology, express the MHC class II machinery, and are distinct from all previously reported DC and ILC3 subsets, but share transcriptional and epigenetic similarities with DC2 and ILC3. We have developed procedures to isolate and expand them in vitro, enabling their functional characterization. R-DC-like cells proliferate in vitro, continue to express RORγt, and differentiate into CD1c+ DC2-like cells. They stimulate the proliferation of allogeneic T cells. The identification of human R-DC-like cells with proliferative potential and plasticity toward CD1c+ DC2-like cells will prompt further investigation into their impact on immune homeostasis, inflammation, and autoimmunity.