Expanded CD56superbrightCD16+ NK Cells from Ovarian Cancer Patients Are Cytotoxic against Autologous Tumor in a Patient-Derived Xenograft Murine Model

Bulk and single-cell transcriptomics identify gene signatures of stem cell-derived NK cell donors with superior cytolytic activity

Allogeneic natural killer (NK) cell therapies are a valuable treatment option for cancer, given their remarkable safety and favorable efficacy profile. Although the use of allogeneic donors allows for off-the-shelf and timely patient treatment, intrinsic interindividual differences put clinical efficacy at risk. The identification of donors with superior anti-tumor activity is essential to ensure the success of adoptive NK cell therapies. Here, we investigated the heterogeneity of 10 umbilical cord blood stem cell-derived NK cell batches. First, we evaluated the donors' cytotoxic potential against tumor cell lines from solid and hematological cancer indications, to distinguish a group of superior, "excellent" killers (4/10), compared with "good" killers (6/10). Next, bulk and single-cell RNA sequencing, performed at different stages of NK differentiation, revealed distinct transcriptomic features of the two groups. Excellent donors showed an enrichment in cytotoxicity pathways and a depletion of myeloid traits, linked to the presence of a larger population of effector-like NK cells early on during differentiation. Consequently, we defined a multi-factorial gene expression signature able to predict the donors' cytotoxic potential. Our study contributes to the identification of key traits of superior NK cell batches, supporting the development of efficacious NK therapeutics and the achievement of durable anti-tumor responses.

Tumor microenvironment induced switch to mitochondrial metabolism promotes suppressive functions in immune cells

Understanding the intricacies of the metabolic phenotype in immune cells and its plasticity within the tumor microenvironment is pivotal in understanding the pathology and prognosis of cancer. Unfavorable conditions and cellular stress in the tumor microenvironment (TME) exert a profound impact on cellular functions in immune cells, thereby influencing both tumor progression and immune responses. Elevated AMP:ATP ratio, a consequence of limited glucose levels, activate AMP-activated protein kinase (AMPK) while concurrently repressing the activity of mechanistic target of rapamycin (mTOR) and hypoxia-inducible factor 1-alpha (HIF-1α). The intricate balance between AMPK, mTOR, and HIF-1α activities defines the metabolic phenotype of immune cells in the TME. These Changes in metabolic phenotype are strongly associated with immune cell functions and play a crucial role in creating a milieu conducive to tumor progression. Insufficiency of nutrient and oxygen supply leads to a metabolic shift in immune cells characterized by a decrease in glycolysis and an increase in oxidative phosphorylation (OXPHOS) and fatty acid oxidation (FAO) rates. In most cases, this shift in metabolism is accompanied by a compromise in the effector functions of these immune cells. This metabolic adaptation prompts immune cells to turn down their effector functions, entering a quiescent or immunosuppressive state that may support tumor growth. This article discusses how tumor microenvironment alters the metabolism in immune cells leading to their tolerance and tumor progression, with emphasis on mitochondrial metabolism (OXPHOS and FAO).

The Immune Response of Cancer Cells in Breast and Gynecologic Neoplasms

Cancer diseases constitute a major health problem which leads to the death of millions of people annually. They are unique among other diseases because cancer cells can perfectly adapt to the environment that they create themselves. This environment is usually highly hostile and for normal cells it would be hugely difficult to survive, however neoplastic cells not only can survive but also manage to proliferate. One of the reasons is that they can alter immunological pathways which allow them to be flexible and change their phenotype to the one needed in specific conditions. The aim of this paper is to describe some of these immunological pathways that play significant roles in gynecologic neoplasms as well as review recent research in this field. It is of high importance to possess extensive knowledge about these processes, as greater understanding leads to creating more specialized therapies which may prove highly effective in the future.

NK-92 cells labeled with Fe3O4-PEG-CD56/Avastin@Ce6 nanoprobes for the targeted treatment and noninvasive therapeutic evaluation of breast cancer

Adoptive cellular immunotherapy as a promising and alternative cancer therapy platform is critical for future clinical applications. Natural killer (NK) cells have attracted attention as an important type of innate immune regulatory cells that can rapidly kill multiple adjacent cancer cells. However, these cells are significantly less effective in treating solid tumors than in treating hematological tumors. Herein, we report the synthesis of a Fe3O4-PEG-CD56/Avastin@Ce6 nanoprobe labeled with NK-92 cells that can be used for adoptive cellular immunotherapy, photodynamic therapy and dual-modality imaging-based in vivo fate tracking. The labeled NK-92 cells specifically target the tumor cells, which increases the amount of cancer cell apoptosis in vitro. Furthermore, the in vivo results indicate that the labeled NK-92 cells can be used for tumor magnetic resonance imaging and fluorescence imaging, adoptive cellular immunotherapy, and photodynamic therapy after tail vein injection. These data show that the developed multifunctional nanostructure is a promising platform for efficient innate immunotherapy, photodynamic treatment and noninvasive therapeutic evaluation of breast cancer.

Role of adhesion molecules in cancer and targeted therapy

Adhesion molecules mediate cell-to-cell and cell-to-extracellular matrix interactions and transmit mechanical and chemical signals among them. Various mechanisms deregulate adhesion molecules in cancer, enabling tumor cells to proliferate without restraint, invade through tissue boundaries, escape from immune surveillance, and survive in the tumor microenvironment. Recent studies have revealed that adhesion molecules also drive angiogenesis, reshape metabolism, and are involved in stem cell self-renewal. In this review, we summarize the functions and mechanisms of adhesion molecules in cancer and the tumor microenvironment, as well as the therapeutic strategies targeting adhesion molecules. These studies have implications for furthering our understanding of adhesion molecules in cancer and providing a paradigm for exploring novel therapeutic approaches.

Correlation between PD-L1 expression of the tumour cells and lymphocytes infiltration in the invasive front of urothelial carcinoma

PURPOSE

Programmed cell death-ligand 1 (PD-L1) as a cell surface glycoprotein can inhibit T cell function when binding to its receptor, PD-1. The newly developed therapy of targeting PD-1/PD-L1 signal pathway has shown great promise for the treatment of non-small cell lung cancer as well as melanoma. Approved by Food and Drug Administration, atezolizumab has become the first new drug to treat advanced bladder cancer. The aim of this study is to evaluate whether PD-L1 is associated with the lymphocytes infiltration in the tumour microenvironment and to assess the prognostic value of PD-L1 expression.

MATERIALS AND METHODS

Among 96 invasive bladder urothelial carcinomas, some were used to construct tissue-microarrays, and some cases with shallow infiltration or large heterogeneity were performed, respectively, for the following work. By means of immunohistochemistry and HE, PD-L1 expression and immune cell infiltration in the invasive front of urothelial carcinoma were analysed.

RESULTS

We find that PD-L1 expression in tumour cells and lymphocytes are significantly associated with more tumour infiltrating lymphocytes (TILs) and more T cells. The integrated TILs, T-PD-L1 and I-PD-L1 are not significantly correlated with the overall survival (OS) of patients. However, the combination of T-PD-L1 and TILs, T-PD-L1 and I-PD-L1 is significantly correlated with the OS of patients. The T-PD-L1 (-)/TIL (-) group show the best prognosis and the T-PD-L1 (+)/I-PD-L1 (-) group show the worst prognosis. Furthermore, a multivariate analysis reveal that PD-L1 expression of lymphocytes is an independent prognostic factor for OS of patients.

CONCLUSIONS

Our study reveal that PD-L1 of tumour cells are associated with the corresponding T cells infiltration and that the combination of T-PD-L1 and I-PD-L1, T-PD-L1 and TILs could be a relevant marker for the determination of the prognostic role of patients with the urothelial carcinoma.

Charting a killer course to the solid tumor: strategies to recruit and activate NK cells in the tumor microenvironment

The ability to expand and activate natural Killer (NK) cells ex vivo has dramatically changed the landscape in the development of novel adoptive cell therapies for treating cancer over the last decade. NK cells have become a key player for cancer immunotherapy due to their innate ability to kill malignant cells while not harming healthy cells, allowing their potential use as an "off-the-shelf" product. Furthermore, recent advancements in NK cell genetic engineering methods have enabled the efficient generation of chimeric antigen receptor (CAR)-expressing NK cells that can exert both CAR-dependent and antigen-independent killing. Clinically, CAR-NK cells have shown promising efficacy and safety for treating CD19-expressing hematologic malignancies. While the number of pre-clinical studies using CAR-NK cells continues to expand, it is evident that solid tumors pose a unique challenge to NK cell-based adoptive cell therapies. Major barriers for efficacy include low NK cell trafficking and infiltration into solid tumor sites, low persistence, and immunosuppression by the harsh solid tumor microenvironment (TME). In this review we discuss the barriers posed by the solid tumor that prevent immune cell trafficking and NK cell effector functions. We then discuss promising strategies to enhance NK cell infiltration into solid tumor sites and activation within the TME. This includes NK cell-intrinsic and -extrinsic mechanisms such as NK cell engineering to resist TME-mediated inhibition and use of tumor-targeted agents such as oncolytic viruses expressing chemoattracting and activating payloads. We then discuss opportunities and challenges for using combination therapies to extend NK cell therapies for the treatment of solid tumors.

Sequential Exposure to IL21 and IL15 During Human Natural Killer Cell Expansion Optimizes Yield and Function

Natural killer (NK) cells are frequently expanded for the clinic using irradiated, engineered K562 feeder cells expressing a core transgene set of membrane-bound (mb) IL15 and/or mbIL21 together with 41BBL. Prior comparisons of mbIL15 to mbIL21 for NK expansion lack comparisons of key attributes of the resulting NK cells, including their high-dimensional phenotype, polyfunctionality, the breadth and potency of cytotoxicity, cellular metabolism, and activity in xenograft tumor models. Moreover, despite multiple rounds of K562 stimulation, studies of sequential use of mbIL15- and mbIL21-based feeder cells are absent. We addressed these gaps and found that using mbIL15- versus mbIL21-based feeder cells drove distinct phenotypic and functional profiles. Feeder cells expressing mbIL15 alone drove superior functionality by nearly all measures, whereas those expressing mbIL21 alone drove superior yield. In combination, most attributes resembled those imparted by mbIL21, whereas in sequence, NK yield approximated that imparted by the first cytokine, and the phenotype, transcriptome, and function resembled that driven by the second cytokine, highlighting the plasticity of NK cell differentiation. The sequence mbIL21 followed by mbIL15 was advantageous in achieving significant yields of highly functional NK cells that demonstrated equivalent in vivo activity to those expanded by mbIL15 alone in two of three xenograft models. Our findings define the impact of mbIL15 versus mbIL21 during NK expansion and reveal a previously underappreciated tradeoff between NK yield and function for which sequential use of mbIL21-based followed by mbIL15-based feeder cells may be the optimal approach in many settings.

Classification of the tumor immune microenvironment and associations with outcomes in patients with metastatic melanoma treated with immunotherapies

BACKGROUND

Tumor microenvironment (TME) characteristics are potential biomarkers of response to immune checkpoint inhibitors in metastatic melanoma. This study developed a method to perform unsupervised classification of TME of metastatic melanoma.

METHODS

We used multiplex immunohistochemical and quantitative pathology-derived assessment of immune cell compositions of intratumoral and peritumoral regions of metastatic melanoma baseline biopsies to classify TME in relation to response to anti-programmed cell death protein 1 (PD-1) monotherapy or in combination with anti-cytotoxic T-cell lymphocyte-4 (ipilimumab (IPI)+PD-1).

RESULTS

Spatial profiling of CD8+T cells, macrophages, and melanoma cells, as well as phenotypic PD-1 receptor ligand (PD-L1) and CD16 proportions, were used to identify and classify patients into one of three mutually exclusive TME classes: immune-scarce, immune-intermediate, and immune-rich tumors. Patients with immune-rich tumors were characterized by a lower proportion of melanoma cells and higher proportions of immune cells, including higher PD-L1 expression. These patients had higher response rates and longer progression-free survival (PFS) than those with immune-intermediate and immune-scarce tumors. At a median follow-up of 18 months (95% CI: 6.7 to 49 months), the 1-year PFS was 76% (95% CI: 64% to 90%) for patients with an immune-rich tumor, 56% (95% CI: 44% to 72%) for those with an immune-intermediate tumor, and 33% (95% CI: 23% to 47%) for patients with an immune-scarce tumor. A higher response rate was observed in patients with an immune-scarce or immune-intermediate tumor when treated with IPI+PD-1 compared with those treated with PD-1 alone.

CONCLUSIONS

Our study provides an automatic TME classification method that may predict the clinical efficacy of immunotherapy for patients with metastatic melanoma.

Pan-cancer analysis of TASL: a novel immune infiltration-related biomarker for tumor prognosis and immunotherapy response prediction

BACKGROUND

New immunotherapeutic strategies based on predictors are urgently needed. Toll-like receptor adaptor interacting with SLC15A4 on the lysosome (TASL) was recently confirmed to fulfill an important role in the innate immune response. However, whether TASL is involved in tumor development and immunotherapy response prediction has not been reported.

METHODS

TCGA and GTEx were used to yield transcriptional, genetic, and epigenetic levels of TASL in 33 cancer types. CIBERSORT was used to explore the correlation between TASL expression and multiple immune-related signatures and tumor-infiltrating immune cell content in different cancer types. The ability of TASL to predict tumor immunotherapy response was analyzed in seven datasets. Finally, we tested TASL expression in human glioma cell lines and tissue samples and analyzed its correlation with clinicopathological parameters.

RESULTS

TASL is widely heterogeneous at the transcriptional, genetic, and epigenetic levels. High TASL expression is an independent poor prognostic factor for immune "cold" tumor Low-Grade Glioma (LGG) but an opposite factor for "hot" tumors Lung Adenocarcinoma (LUAD) and Skin Cutaneous Melanoma (SKCM). TASL may affect tumor immune infiltration by mediating tumor-infiltrating lymphocytes and tumor-associated macrophages. It may differentially affect the prognosis of the three cancers by regulating the immunosuppressive microenvironment in LGG and the immunostimulatory microenvironment in LUAD and SKCM. High TASL expression is a potential biomarker for the positive response to immunotherapy in cancers such as SKCM and was also experimentally confirmed to be positively associated with adverse clinicopathological features of gliomas.

CONCLUSION

TASL expression is an independent prognostic factor for LGG, LUAD, and SKCM. High TASL expression is a potential biomarker for the positive response to immunotherapy in certain cancer types such as SKCM. Further basic studies focusing on TASL expression and tumor immunotherapy are urgently needed.

Development of an antibody-ligand fusion protein scFvCD16A-sc4-1BBL in Komagataella phaffii with stimulatory activity for Natural Killer cells

BACKGROUND

Natural killer (NK) cell-based immunotherapies have demonstrated substantial potential for the treatment of hematologic malignancies. However, its application is limited due to the difficulty in the production of a large number of NK cells in vitro and the insufficient therapeutic efficacy against solid tumors in vivo. Engineered antibodies or fusion proteins targeting activating receptors and costimulatory molecules of NK cells have been developed to encounter these problems. They are mostly produced in mammalian cells with high cost and long processing times. Yeast systems, such as Komagataella phaffii, present a convenient manipulation of microbial systems with the key advantages of improved folding machinery and low cost.

RESULTS

In this study, we designed an antibody fusion protein scFvCD16A-sc4-1BBL, composed of the single chain variant fragment (scFv) of anti-CD16A antibody and the three extracellular domains (ECDs) of human 4-1BBL in a single-chain format (sc) with the GS linker, aiming to boost NK cell proliferation and activation. This protein complex was produced in the K. phaffii X33 system and purified by affinity chromatography and size exclusion chromatography. The scFvCD16A-sc4-1BBL complex showed comparable binding abilities to its two targets human CD16A and 4-1BB as its two parental moieties (scFvCD16A and monomer ECD (mn)4-1BBL). scFvCD16A-sc4-1BBL specifically stimulated the expansion of peripheral blood mononuclear cell (PBMC)-derived NK cells in vitro. Furthermore, in the ovarian cancer xenograft mouse model, adoptive NK cell infusion combined with intraperitoneal (i.p) injection of scFvCD16A-sc4-1BBL further reduced the tumor burden and prolonged the survival time of mice.

CONCLUSION

Our studies demonstrate the feasibility of the expression of the antibody fusion protein scFvCD16A-sc4-1BBL in K. phaffii with favourable properties. scFvCD16A-sc4-1BBL stimulates PBMC-derived NK cell expansion in vitro and improves the antitumor activity of adoptively transferred NK cells in a murine model of ovarian cancer and may serve as a synergistic drug for NK immunotherapy in future research and applications.

Modulating the tumor immune microenvironment with nanoparticles: A sword for improving the efficiency of ovarian cancer immunotherapy

With encouraging antitumor effects, immunotherapy represented by immune checkpoint blockade has developed into a mainstream cancer therapeutic modality. However, only a minority of ovarian cancer (OC) patients could benefit from immunotherapy. The main reason is that most OC harbor a suppressive tumor immune microenvironment (TIME). Emerging studies suggest that M2 tumor-associated macrophages (TAMs), T regulatory cells (Tregs), myeloid-derived suppressor cells (MDSCs), and cancer-associated fibroblasts (CAFs) are enriched in OC. Thus, reversing the suppressive TIME is considered an ideal candidate for improving the efficiency of immunotherapy. Nanoparticles encapsulating immunoregulatory agents can regulate immunocytes and improve the TIME to boost the antitumor immune response. In addition, some nanoparticle-mediated photodynamic and photothermal therapy can directly kill tumor cells and induce tumor immunogenic cell death to activate antigen-presenting cells and promote T cell infiltration. These advantages make nanoparticles promising candidates for modulating the TIME and improving OC immunotherapy. In this review, we analyzed the composition and function of the TIME in OC and summarized the current clinical progress of OC immunotherapy. Then, we expounded on the promising advances in nanomaterial-mediated immunotherapy for modulating the TIME in OC. Finally, we discussed the obstacles and challenges in the clinical translation of this novel combination treatment regimen. We believe this resourceful strategy will open the door to effective immunotherapy of OC and benefit numerous patients.

The metabolic characteristic of decidual immune cells and their unique properties in pregnancy loss

Maternal tolerance to semi- or fully allograft conceptus is a prerequisite for the maintenance of pregnancy. Once this homeostasis is disrupted, it may result in pregnancy loss. As a potential approach to prevent pregnancy loss, targeting decidual immune cells (DICs) at the maternal-fetal interface has been suggested. Although the phenotypic features and functions of DIC have been extensively profiled, the regulatory pathways for this unique immunological adaption have yet to be elucidated. In recent years, a pivotal mechanism has been highlighted in the area of immunometabolism, by which the changes in intracellular metabolic pathways in DIC and interaction with the adjacent metabolites in the microenvironment can alter their phenotypes and function. More inspiringly, the manipulation of metabolic profiling in DIC provides a novel avenue for the prevention and treatment of pregnancy loss. Herein, this review highlights the major metabolic programs (specifically, glycolysis, ATP-adenosine metabolism, lysophosphatidic acid metabolism, and amino acid metabolism) in multiple immune cells (including decidual NK cells, macrophages, and T cells) and their integrations with the metabolic microenvironment in normal pregnancy. Importantly, this perspective may help to provide a potential therapeutic strategy for reducing pregnancy loss via targeting this interplay.

Natural Killer Cells: the Missing Link in Effective Treatment for High-Grade Serous Ovarian Carcinoma

OPINION STATEMENT

Ovarian cancer (OC), especially high-grade serous cancer (HGSC), is a highly heterogeneous malignancy with limited options for curative treatment and a high frequency of relapse. Interactions between OC and the immune system may permit immunoediting and immune escape, and current standard of care therapies can influence immune cell infiltration and function within the tumor microenvironment. Natural killer (NK) cells are involved in cancer immunosurveillance and immunoediting and can be activated by therapy, but deliberate approaches to maximize NK cell reactivity for treatment of HGSC are in their infancy. NK cells may be the ideal target for immunotherapy of HGSC. The diverse functions of NK cells, and their established roles in immunosurveillance, make them attractive candidates for more precise and effective HGSC treatment. NK cells' functional capabilities differ because of variation in receptor expression and genetics, with meaningful impacts on their anticancer activity. Studying HGSC:NK cell interactions will define the features that predict the best outcomes for patients with the disease, but the highly diverse nature of HGSC will likely require combination therapies or approaches to simultaneously target multiple, co-existing features of the tumor to avoid tumor escape and relapse. We expect that the ideal therapy will enable NK cell infiltration and activity, reverse immunosuppression within the tumor microenvironment, and enable effector functions against the diverse subpopulations that comprise HGSC.

Elevated Expression of Gamma-Glutamyl Hydrolase Is Associated With Poor Prognosis and Altered Immune Signature in Uterine Corpus Endometrial Carcinoma

Uterine corpus endometrial carcinoma (UCEC) is a common malignant tumor of the female reproductive system with poor prognosis in advanced, recurrent, and metastatic cases. Identification of reliable molecular markers will help in the development of clinical strategies for early detection, diagnosis, and intervention. Gamma-glutamyl hydrolase (GGH) is a key enzyme in folate metabolism pathway. High expression of GGH is associated with severe clinicopathological features and poor prognosis of several cancers. High GGH expression is also related to cell resistance to antifolate drugs such as methotrexate. In this study we focused on the prognostic value of immunohistochemical GGH expression level in UCEC tissue and RNA-seq data from The Cancer Genome Atlas to establish associations with clinical features and outcomes. Further, we conducted comprehensive bioinformatics analyses to identify and functionally annotate differentially expressed genes (DEGs) associated with UCEC upregulation and assessed the effects of upregulation on immune infiltration. Both GGH mRNA and protein expression levels were elevated in tumor tissues, and higher expression was significantly associated with advanced clinicopathological features and poor prognosis by univariate analysis. Further multivariate analysis identified elevated GGH expression as an independent risk factor for poor outcome. Nomograms including GGH expression yielded a c-index for disease-specific survival prediction of 0.884 (95% confidence interval: 0.861–0.907). A total of 520 DEGs (111 upregulated and 409 downregulated) were identified between high and low GGH expression groups. Analysis using Gene ontology, Kyoto Encyclopedia of Genes and Genomes pathway, Gene set enrichment analysis, and protein‒protein interaction indicated significant associations of altered GGH expression with cell proliferation, immune response, and the occurrence and development of UCEC tumors. Finally, GGH expression level was associated with high Th2 cell and low natural killer CD56bright cell infiltration. Collectively, these findings indicate that GGH drives UCEC progression and could be a useful biomarker for survival prediction as well as a therapeutic target.

Role of NK Cells in Tumor Progression

Natural Killer (NK) cells are effector lymphocytes with the ability to generate an antitumor response. NK cells encompass a diverse group of subsets with different properties and have the capacity to kill cancer cells by different means. However, tumor cells have developed several mechanisms to evade NK cell-mediated killing. In this chapter, we summarize some aspects of NK cell biology with the aim to understand the competence of these cells and explore some of the challenges that NK cells have to face in different malignancies. Moreover, we will review the current knowledge about the role of NK cells in tumor progression and describe their phenotype and effector functions in tumor tissues and peripheral blood from cancer patients. Finally, we will recapitulate several findings from different studies focused on determining the prognostic value of NK cells in distinct cancers.

Anti-Tumor Activity of Expanded PBMC-Derived NK Cells by Feeder-Free Protocol in Ovarian Cancer

Natural killer (NK) cells have shown great therapeutic potential against a wide range of cancers due to their pan-specific target recognition. Numerous reports indicate that NK cell immunotherapy is an effective therapeutic approach for treating hematological malignancies, but shows limited effects against solid tumors. In this study, several models of ovarian cancer (OC) were used to test the anti-cancer effects of NK cells derived from human peripheral blood mononuclear cells and expanded using a feeder cell-free expansion system (eNKs). The results show that eNKs exhibit potent inhibitory activity on tumor growth in different ovarian cancer xenograft mice (i.e., solid tumors, abdominal metastatic tumors, and ascites), importantly, in a dose-dependent manner. Moreover, adoptive transfer of eNKs resulted in significant reduction in ascites formation in OC peritoneal tumor models, and especially in reducing intraperitoneal ascites. We found that eNKs could migrate to the tumor site, retain their activity, and proliferate to maintain high cell counts in cutaneous xenograft mice. In addition, when increased the infusion with a high dose of 12 × 107 cells/mouse, Graft-versus-host disease could be induced by eNK. These data show that eNK cell immunotherapy could be a promising treatment strategy for ovarian cancers, including solid tumors and ascites.

High Density of CD16+ Tumor-Infiltrating Immune Cells in Recurrent Ovarian Cancer Is Associated with Enhanced Responsiveness to Chemotherapy and Prolonged Overall Survival

Simple Summary

The late—and in most cases at an advanced stage—diagnosis of patients with ovarian cancer (OC) and the high recurrence rate make this malignant disease the most lethal among gynecological cancers. With a mortality-to-incidence ratio of 0.74, OC is a tumor with the fifth most frequent progression after esophageal cancer, liver cancer, pancreatic cancer, and brain tumors. The updated FIGO staging system is the gold standard in the clinic and includes surgical, radiologic, and pathologic elements to describe the extent of OC. This system is used to describe tumor extent, plan further therapy, and predict prognosis. However, it is consistently observed that patients with identical stages and treatments have a completely different outcome in terms of survival and recurrence. This fact indicates that this classification alone is not sufficient for the prognosis of OC in the vast majority of cases. Over the last two decades, many studies have demonstrated the critical role of the tumor microenvironment in tumorigenesis, progression, prognosis, and response to chemotherapy. In the current study, we investigate the role of CD16 expression in OC.

Abstract

Background: Ovarian cancer (OC) is the most aggressive and fatal malignancy of the female reproductive system. Debulking surgery with adjuvant chemotherapy represents the standard treatment, but recurrence rates are particularly high. Over the past decades, the association between the immune system and cancer progression has been extensively investigated. However, the interaction between chemotherapy and cancer immune infiltration is still unclear. In this study, we examined the prognostic role of CD16 expression in OC, as related to the effectiveness of standard adjuvant chemotherapy treatment. Methods: We analyzed the infiltration by immune cells expressing CD16, a well-characterized natural killer (NK) and myeloid cell marker, in a tissue microarray (TMA) of 47 patient specimens of primary OCs and their matching recurrences by immunohistochemistry (IHC). We analyzed our data first in the whole cohort, then in the primary tumors, and finally in recurrences. We focused on recurrence-free survival (RFS), overall survival (OS), and chemosensitivity. Chemosensitivity was defined as RFS of more than 6 months. Results: There was no significant correlation between CD16 expression and prognosis in primary carcinomas. However, interestingly, a high density of CD16-expressing tumor-infiltrating immune cells (TICs) in recurrent carcinoma was associated with better RFS (p = 0.008) and OS (p = 0.029). Moreover, high CD16 cell density in recurrent ovarian carcinoma showed a significant association with chemosensitivity (p = 0.034). Univariate Cox regression analysis revealed that the high expression of CD16+ TIC in recurrent cancer biopsies is significantly associated with an increased RFS (HR = 0.49; 95% CI 0.24–0.99; p = 0.047) and OS (HR = 0.28; 95% CI 0.10–0.77; p = 0.013). However, this was not independent of known prognostic factors such as age, FIGO stage, resection status, and the number of chemotherapy cycles. Conclusions: The high density of CD16-expressing TICs in recurrent ovarian cancer is associated with a better RFS and OS, thereby suggesting a previously unsuspected interaction between standard OC chemotherapy and immune cell infiltration.

Making a Killer: Selecting the Optimal Natural Killer Cells for Improved Immunotherapies

Over the past 20 years natural killer (NK) cell-based immunotherapies have emerged as a safe and effective treatment option for patients with relapsed or refractory leukemia. Unlike T cell-based therapies, NK cells harbor an innate capacity to eliminate malignant cells without prior sensitization and can be adoptively transferred between individuals without the need for extensive HLA matching. A wide variety of therapeutic NK cell sources are currently being investigated clinically, including allogeneic donor-derived NK cells, stem cell-derived NK cells and NK cell lines. However, it is becoming increasingly clear that not all NK cells are endowed with the same antitumor potential. Despite advances in techniques to enhance NK cell cytotoxicity and persistence, the initial identification and utilization of highly functional NK cells remains essential to ensure the future success of adoptive NK cell therapies. Indeed, little consideration has been given to the identification and selection of donors who harbor NK cells with potent antitumor activity. In this regard, there is currently no standard donor selection criteria for adoptive NK cell therapy. Here, we review our current understanding of the factors which govern NK cell functional fate, and propose a paradigm shift away from traditional phenotypic characterization of NK cell subsets towards a functional profile based on molecular and metabolic characteristics. We also discuss previous selection models for NK cell-based immunotherapies and highlight important considerations for the selection of optimal NK cell donors for future adoptive cell therapies.

Jinfukang inhibits lung cancer metastasis by upregulating CX3CL1 to recruit NK cells to kill CTCs

ETHNOPHARMACOLOGICAL RELEVANCE

Circulating tumor cells (CTCs) play an important role in tumor metastasis and may be a target for metastasis prevention. The traditional Chinese medicine Jinfukang functions to improve immunity, prevent metastasis, and prolong lung cancer patient survival periods. Yet, whether Jinfukang prevents metastasis by regulating immune cells to clearance CTCs is still unknown.

AIM OF THE STUDY

To explore the anti-metastasis mechanism of Jinfukang from the perspective of regulating NK cells to clear CTCs.

MATERIALS AND METHODS

CTC-TJH-01 cell was treated with Jinfukang. Cytokine chip was used to detect cytokines in cell culture supernatant. Lymphocyte recruitment assay was detected by Transwell and flow cytometry. Protein expression was analysis by Western blot. LDH kit was used to detect cytotoxicity. NOD-SCID mice used for tail vein injection to study lung metastasis.

RESULTS

Jinfukang could promote the expression and secretion of the chemokine CX3CL1 by CTCs. In addition, Jinfukang could promote the recruitment of natural killer (NK) cells by CTCs and significantly increase the cytotoxic effect of NK cells on CTCs. Moreover, Jinfukang could upregulate the expression of FasL and promote the secretion of TNF-α by NK cells and that NK cells could induce the apoptosis of CTCs through the Fas/FasL signaling pathway. Finally, we confirmed that Jinfukang could promote NK cells to kill CTCs and then inhibit lung cancer metastasis in vivo. The above effects of Jinfukang could be partially reversed by an anti-CX3CL1 mAb.

CONCLUSIONS

These results suggest that Jinfukang may prevent lung cancer metastasis by enhancing the clearance of CTCs in the peripheral blood by NK cells, providing evidence for the anti-metastasis effect of Jinfukang.

Optimising NK cell metabolism to increase the efficacy of cancer immunotherapy

Immunotherapy has ushered in an exciting new era for cancer treatment. The recent discovery and success of immune checkpoint blockade and chimeric antigen receptor (CAR) T cell adoptive cell transfer has raised interest in using other immune cells, including Natural Killer (NK) cells, which might overcome some limitations with CAR T cell therapy. In this review article, we discuss the evidence that cellular metabolism is crucial for NK cell effector function. Additionally, potential strategies to optimise the metabolism of therapeutic NK cells for improved function within the metabolically adverse tumour microenvironment will be explored.

Metabolic flexibility determines human NK cell functional fate in the tumor microenvironment

NK cells are central to anti-tumor immunity and recently showed efficacy for treating hematologic malignancies. However, their dysfunction in the hostile tumor microenvironment remains a pivotal barrier for cancer immunotherapies against solid tumors. Using cancer patient samples and proteomics, we found that human NK cell dysfunction in the tumor microenvironment is due to suppression of glucose metabolism via lipid peroxidation-associated oxidative stress. Activation of the Nrf2 antioxidant pathway restored NK cell metabolism and function and resulted in greater anti-tumor activity in vivo. Strikingly, expanded NK cells reprogrammed with complete metabolic substrate flexibility not only sustained metabolic fitness but paradoxically augmented their tumor killing in the tumor microenvironment and in response to nutrient deprivation. Our results uncover that metabolic flexibility enables a cytotoxic immune cell to exploit the metabolic hostility of tumors for their advantage, addressing a critical hurdle for cancer immunotherapy.

Expanded human NK cells armed with CAR uncouple potent anti-tumor activity from off-tumor toxicity against solid tumors

Despite the remarkable success of chimeric antigen receptor (CAR)-T cells against hematologic malignancies, severe off-tumor effects have constrained their use against solid tumors. Recently, CAR-engineered natural killer (NK) cells have emerged as an effective and safe alternative. Here, we demonstrate that HER2 CAR-expression in NK cells from healthy donors and patients with breast cancer potently enhances their anti-tumor functions against various HER2-expressing cancer cells, regardless of MHC class I expression. Moreover, HER2 CAR-NK cells exert higher cytotoxicity than donor-matched HER2 CAR-T cells against tumor targets. Importantly, unlike CAR-T cells, HER2 CAR-NK cells do not elicit enhanced cytotoxicity or inflammatory cytokine production against non-malignant human lung epithelial cells with basal HER2 expression. Further, HER2 CAR-NK cells maintain high cytotoxic function in the presence of immunosuppressive factors enriched in solid tumors. These results show that CAR-NK cells may be a highly potent and safe source of immunotherapy in the context of solid tumors.

•

Primary HER2 CAR-NK cells from patients with cancer have potent anti-tumor functions

•

HER2 CAR-NK cells have a higher tumor killing capacity than HER2 CAR-T cells

•

HER2 CAR-NK cells are not overly activated against HER2+ lung epithelial cells

•

CAR-NK cells can overcome inhibition by the immunosuppressive factors TGF-β and PGE2

Human NK Cells in Autologous Hematopoietic Stem Cell Transplantation for Cancer Treatment

Simple Summary

Natural killer (NK) cells are key elements of the innate immune system that have the ability to kill transformed (tumor and virus-infected) cells without prior sensitization. Hematopoietic stem cell transplantation (HSCT) is a medical procedure used in the treatment of a variety of cancers. The early reconstitution of NK cells after HSCT and their functions support the therapeutic potential of these cells in allogenic HSCT. However, the role of NK cells in autologous HSCT is less clear. In this review, we have summarized general aspects of NK cell biology. In addition, we have also reviewed factors that affect autologous HSCT outcome, with particular attention to the role played by NK cells.

Abstract

Natural killer (NK) cells are phenotypically and functionally diverse lymphocytes with the ability to recognize and kill malignant cells without prior sensitization, and therefore, they have a relevant role in tumor immunosurveillance. NK cells constitute the main lymphocyte subset in peripheral blood in the first week after hematopoietic stem cell transplantation (HSCT). Although the role that NK cells play in allogenic HSCT settings has been documented for years, their significance and beneficial effects associated with the outcome after autologous HSCT are less recognized. In this review, we have summarized fundamental aspects of NK cell biology, such as, NK cell subset diversity, their effector functions, and differentiation. Moreover, we have reviewed the factors that affect autologous HSCT outcome, with particular attention to the role played by NK cells and their receptor repertoire in this regard.

Expanded human NK cells from lung cancer patients sensitize patients' PDL1-negative tumors to PD1-blockade therapy

Lung cancer remains the leading cause of cancer death worldwide despite the significant progress made by immune checkpoint inhibitors, including programmed death receptor-1 (PD1)/PD ligand 1 (PDL1)-blockade therapy. PD1/PDL1-blockade has achieved unprecedented tumor regression in some patients with advanced lung cancer. However, the majority of patients fail to respond to PD1/PDL1 inhibitors. The high rate of therapy non-response results from insufficient PDL1 expression on most patients' tumors and the presence of further immunosuppressive mechanisms in the tumor microenvironment. Here, we sensitize non-responding tumors from patients with lung cancer to PD1-blockade therapy using highly cytotoxic expanded natural killer (NK) cells. We uncover that NK cells expanded from patients with lung cancer dismantle the immunosuppressive tumor microenvironment by maintaining strong antitumor activity against both PDL1+ and PDL1- patient tumors. In the process, through a contact-independent mechanism involving interferon γ, expanded NK cells rescued tumor killing by exhausted endogenous TILs and upregulated the tumor proportion score of PDL1 across patient tumors. In contrast, unexpanded NK cells, which are susceptible to tumor-induced immunosuppression, had no effect on tumor PDL1. As a result, combined treatment of expanded NK cells and PD1-blockade resulted in robust synergistic tumor destruction of initially non-responding patient tumors. Thus, expanded NK cells may overcome the critical roadblocks to extending the prodigious benefits of PD1-blockade therapy to more patients with lung cancer and other tumor types.

Classification of serous ovarian carcinoma based on immunogenomic profiling

Treatment of serous ovarian cancer (SOC) remains a clinical challenge. Classification of SOC based on immunogenomic profiling is important for establishing immunotherapy strategies. We extracted RNA-seq data of SOC from TCGA-OV. The samples were ultimately classified into high immune (Immunity_H) group and low immune (Immunity_L) group based on the immunogenomic profiling of 29 immune signatures by using unsupervised machine learning methods and modified by multifaceted characterization of immune response. High immune group showed the lower tumor purity and higher anti-tumor immune activity, and the higher expressions of PDCD1, CD274 and CTLA4. Furthermore, the overall survival time and the progression-free interval were significantly longer in high-immun group. The differentially expressed genes were mainly enriched in some immune response related functional terms and PI3K-AKT signaling pathway. According to ImmuCellAI, the abundance of various T cell subtypes in high immune group were significantly higher than those in low immune group. This novel immunotyping shows promise for prognostic and immunotherapeutic stratification in SOC patients.

HLA-DR-expressing NK cells: Effective killers suspected for antigen presentation

HLA-DR-expressing cells comprise an intriguing group of NK cells, which combine phenotypic characteristics of both NK cells and dendritic cells. These cells can be found in humans and mice; they are present in blood and tissues in healthy conditions and can expand in a spectrum of pathologies. HLA-DR⁺ NK cells are functionally active: they produce proinflammatory cytokines, degranulate, and easily proliferate in response to stimuli. Additionally, HLA-DR⁺ NK cells seem able to take in and then present certain antigens to CD4⁺ and CD8⁺ T cells, inducing their activation and proliferation, which puts them closer to professional antigen-presenting cells. It appears that these NK cells should be considerable players of the innate immune system, both due to their functional activity and regulation of the innate and adaptive immune responses. In this review, for the first time, we provide a detailed description and analysis of the available data characterizing phenotypic, developmental, and functional features of the HLA-DR⁺ NK cells in a healthy condition and a disease.

The Ovarian Cancer Tumor Immune Microenvironment (TIME) as Target for Therapy: A Focus on Innate Immunity Cells as Therapeutic Effectors

Ovarian cancer (OvCA) accounts for one of the leading causes of death from gynecologic malignancy. Despite progress in therapy improvements in OvCA, most patients develop a recurrence after first-line treatments, dependent on the tumor and non-tumor complexity/heterogeneity of the neoplasm and its surrounding tumor microenvironment (TME). The TME has gained greater attention in the design of specific therapies within the new era of immunotherapy. It is now clear that the immune contexture in OvCA, here referred as tumor immune microenvironment (TIME), acts as a crucial orchestrator of OvCA progression, thus representing a necessary target for combined therapies. Currently, several advancements of antitumor immune responses in OvCA are based on the characterization of tumor-infiltrating lymphocytes, which have been shown to correlate with a significantly improved clinical outcome. Here, we reviewed the literature on selected TIME components of OvCA, such as macrophages, neutrophils, γδ T lymphocytes, and natural killer (NK) cells; these cells can have a role in either supporting or limiting OvCA, depending on the TIME stimuli. We also reviewed and discussed the major (immune)-therapeutic approaches currently employed to target and/or potentiate macrophages, neutrophils, γδ T lymphocytes, and NK cells in the OvCA context.

Evaluation of serum-free media formulations in feeder cell-stimulated expansion of natural killer cells

BACKGROUND

Optimal expansion of therapeutic natural killer (NK) cell products has required media supplementation with human or fetal bovine serum, which raises safety and regulatory concerns for clinical manufacturing. Serum-free media (SFM) have been optimized for T-cell expansion, but few SFM systems have been developed for NK cells. Here, we compare six commercial clinical-grade SFM with our standard fetal bovine serum-containing medium for their ability to support NK cell expansion and function.

METHODS

Human peripheral blood NK cells were expanded in selected media by recursive weekly stimulation with K562-based feeder cells expressing membrane-bound interleukin-21 and CD137L. Expansion was the primary readout, and the best-performing SFM was then compared with standard medium for cytotoxicity, phenotype, degranulation and cytokine secretion. Multiple lots were compared for consistency, and media was analyzed throughout for nutrient consumption and metabolic byproducts.

RESULTS

TexMACS, OpTmizer, SCGM, ABS-001 and StemXVivo demonstrated equal or inferior NK cell expansion kinetics compared with standard medium, but expansion was markedly superior with AIM V + 5% Immune Cell Serum Replacement (ICSR; mean 5448 vs. 2621-fold expansion in 14 days). Surprisingly, NK cells expanded in AIM V + ICSR also showed increased cytotoxicity, tumor necrosis factor α secretion and DNAM-1, NKG2D, NKp30, FasL, granzyme B and perforin expression. Lot-to-lot variability was minimal. Glucose and glutamine consumption were inversely related to lactate and ammonia production.

DISCUSSION

The AIM V + ICSR SFM system supports excellent ex vivo expansion of clinical-grade NK cells with the phenotype and function needed for adoptive immunotherapy.

Targeting tumor microenvironment in ovarian cancer: Premise and promise

Ovarian cancer is the leading cause of gynecological cancer-related mortality globally. The majority of ovarian cancer patients suffer from relapse after standard of care therapies and the clinical benefits from cancer therapies are not satisfactory owing to drug resistance. Certain novel drugs targeting the components of tumor microenvironment (TME) have been approved by US Food and Drug Administration in solid cancers. As such, the passion is rekindled to exploit the role of TME in ovarian cancer progression and metastasis for discovery of novel therapeutics for this deadly disease. In the current review, we revisit the recent mechanistic insights into the contributions of TME to the development, progression, prognosis prediction and therapeutic efficacy of ovarian cancer via modulating cancer hallmarks. We also explored potentially promising predictive and prognostic biomarkers for ovarian cancer patients.

Natural Killer Cell Therapy: A New Treatment Paradigm for Solid Tumors

In treatments of solid tumors, adoptive transfer of ex vivo expanded natural killer (NK) cells has dawned as a new paradigm. Compared with cytotoxic T lymphocytes, NK cells take a unique position targeting tumor cells that evade the host immune surveillance by down-regulating self-antigen presentation. Recent findings highlighted that NK cells can even target cancer stem cells. The efficacy of allogeneic NK cells has been widely investigated in the treatment of hematologic malignancies. In solid tumors, both autologous and allogeneic NK cells have demonstrated potential efficacy. In allogeneic NK cell therapy, the mismatch between the killer cell immunoglobulin-like receptor (KIR) and human leukocyte antigen (HLA) can be harnessed to increase the antitumor activity. However, the allogeneic NK cells cause more adverse events and can be rejected by the host immune system after repeated injections. In this regard, the autologous NK cell therapy is safer. This article reviews the published results of clinical trials and discusses strategies to enhance the efficacy of the NK cell therapy. The difference in immunophenotype of the ex vivo expanded NK cells resulted from different culture methods may affect the final efficacy. Furthermore, currently available standard anticancer therapy, molecularly targeted agents, and checkpoint inhibitors may directly or indirectly enhance the efficacy of NK cell therapy. A recent study discovered that NK cell specific genetic defects are closely associated with the tumor immune microenvironment that determines clinical outcomes. This finding warrants future investigations to find the implication of NK cell specific genetic defects in cancer development and treatment, and NK cell deficiency syndrome should be revisited to enhance our understanding. Overall, it is clear that NK cell therapy is safe and promises a new paradigm for the treatment of solid tumors.

Naturally Killing the Silent Killer: NK Cell-Based Immunotherapy for Ovarian Cancer

Ovarian cancer (OC) is diagnosed in ~22,000 women in the US each year and kills 14,000 of them. Often, patients are not diagnosed until the later stages of disease, when treatment options are limited, highlighting the urgent need for new and improved therapies for precise cancer control. An individual's immune function and interaction with tumor cells can be prognostic of the response to cancer treatment. Current emerging therapies for OC include immunotherapies, which use antibodies or drive T cell-mediated cancer recognition and elimination. In OC, these have been limited by adverse side effects and tumor characteristics including inter- and intra-tumoral heterogeneity, lack of targetable antigens, loss of tumor human leukocyte antigen expression, high levels of immunosuppressive factors, and insufficient immune cell trafficking. Natural killer (NK) cells may be ideal as primary or collateral effectors to these nascent immunotherapies. NK cells exhibit multiple functions that combat immune escape and tumor relapse: they kill targets and elicit inflammation through antigen-independent pathways and detect loss of HLA as a signal for activation. NK cells are efficient mediators of tumor immune surveillance and control, suppressed by the tumor microenvironment and rescued by immune checkpoint blockade. NK cells are regulated by a variety of activating and inhibitory receptors and already known to be central effectors across an array of existing therapies. In this article, we highlight interactions between NK cells and OC and their potential to change the immunosuppressive tumor microenvironment and participate in durable immune control of OC.

What Defines NK Cell Functional Fate: Phenotype or Metabolism?

NK cells are capable of an array of functions that range widely from their classic anti-tumor and anti-viral cytotoxic effector functions, to their critical regulatory roles in controlling inflammatory immune responses and promoting tissue growth. However, the mechanisms that polarize NK cells to these distinct and opposing functions are incompletely understood. NK cell functional subsets are primarily identified and studied based on phenotype, which has served as an accessible means for profiling NK cells and does offer information on NK cell activation state. However, inconsistencies have emerged in using classic phenotypes to inform function, which raise the questions: Can phenotype in fact define NK cell functional fate? What factors do profile and drive NK cell fate? In other immune cells, cell metabolism has been shown to critically determine subset polarization. There is a growing body of evidence that cell metabolism is integral to NK cell effector functions. Glucose-driven glycolysis and oxidative metabolism have been shown to drive classic NK cell anti-tumor and anti-viral effector functions. Recent studies have uncovered a critical role for metabolism in NK cell development, education, and memory generation. In this review, we will draw on the evidence to date to investigate the relationship between NK cell phenotype, metabolism, and functional fate. We explore a paradigm in which the differential activity of metabolic pathways within NK cells produce distinct metabolic fingerprints that comprehensively distinguish and drive the range of NK cell functional abilities. We will discuss future areas of study that are needed to develop and test this paradigm and suggest strategies to efficiently profile NK cells based on metabolism. Given the emerging role of metabolism in driving NK cell fates, profiling and modulating NK cell metabolism holds profound therapeutic potential to tune inflammatory and regulatory NK cell responses to treat disease.

Discovery of a novel natural killer cell line with distinct immunostimulatory and proliferative potential as an alternative platform for cancer immunotherapy

BACKGROUND

Human natural killer (NK) cell lines serve as an attractive source for adoptive immunotherapy, but NK-92 remains the only cell line being assessed in the clinic. Here, we established a novel NK cell line, NK101, from a patient with extra-nodal natural killer/T-cell lymphoma and examined its phenotypic, genomic and functional characteristics.

METHODS

Single cell suspensions from lymphoma tissue were expanded with anti-NKp46/anti-CD2-coated beads in the presence of IL-2. A continuously growing CD56⁺ cell clone was selected and designated as NK101. Flow cytometry and RNA sequencing were used to characterize phenotypic and genomic features of NK101. In vitro cytotoxicity and IFN-γ/TNF-α secretion were measured by flow cytometry-based cytotoxicity assay and enzyme-linked immunosorbent assay, respectively, after direct co-culture with tumor cells. Immunomodulatory potential of NK101 was assessed in an indirect co-culture system using conditioned medium. Finally, in vivo antitumor efficacy was evaluated in an immunocompetent, syngeneic 4T1 mammary tumor model.

RESULTS

NK101 displayed features of CD56^dimCD62L⁺ intermediate stage NK subset with the potential to simultaneously act as a cytokine producer and a cytotoxic effector. Comparative analysis of NK101 and NK-92 revealed that NK101 expressed lower levels of perforin and granzyme B that correlated with weaker cytotoxicity, but produced higher levels of pro-inflammatory cytokines including IFN-γ and TNF-α. Contrarily, NK-92 produced greater amounts of anti-inflammatory cytokines, IL-1 receptor antagonist and IL-10. Genome-wide analysis revealed that genes associated with positive regulation of leukocyte proliferation were overexpressed in NK101, while those with opposite function were highly enriched in NK-92. The consequence of such expressional and functional discrepancies was well-represented in (i) indirect co-culture system where conditioned medium derived from NK101 induced greater proliferation of human peripheral blood mononuclear cells and (ii) immunocompetent 4T1 tumor model where peritumoral injections of NK101 displayed stronger anti-tumor activities by inducing higher tumor-specific immune responses. In a manufacturing context, NK101 not only required shorter recovery time after thawing, but also exhibited faster growth profile than NK-92, yielding more than 200-fold higher cell numbers after 20-day culture.

CONCLUSION

NK101 is a unique NK cell line bearing strong immunostimulatory potential and substantial scalability, providing an attractive source for adoptive cancer immunotherapy.