Cytotoxic Cells Research Articles

Effect of NK cell receptor genetic variation on allogeneic stem cell transplantation outcome and in vitro NK cell cytotoxicity

Natural killer (NK) cells recognize and may kill malignant cells via their cell surface receptors. Killer cell immunoglobulin-like receptor (KIR) genotypes of donors have been reported to adjust the risk of relapse after allogeneic stem cell transplantation (HSCT), particularly in patients with acute myeloid leukemia. To test whether non-KIR NK cell receptors have a similar effect, we screened 1,638 genetic polymorphisms in 21 non-KIR NK cell receptor genes for their associations with relapse and graft-versus-host disease (GVHD) after HSCT in 1,491 HSCT donors (from Finland, the UK, Spain, and Poland), divided into a discovery and replication cohort. Eleven polymorphisms regulating or located in CD226, CD244, FCGR3A, KLRD1, NCR3, and PVRIG were associated with the risks for relapse and GVHD. These associations could not be confirmed in the replication cohort. Blood donor NK cells carrying alleles showing genetic protection for relapse had a higher in vitro NK cell killing activity than non-carriers whereas those with alleles genetically protective for GVHD had lower cytotoxicity, potentially indicating functional effects. Taken together, these results show no robust effects of genetic variation in the tested non-KIR NK cell receptors on the outcome of HSCT.

Optimizing CAR-T cell therapy for solid tumors: current challenges and potential strategies.

Chimeric antigen receptor (CAR)-T cell therapy demonstrates substantial efficacy in various hematological malignancies. However, its application in solid tumors is still limited. Clinical studies report suboptimal outcomes such as reduced cytotoxicity of CAR-T cells and tumor evasion, underscoring the need to address the challenges of sliding cytotoxicity in CAR-T cells. Despite improvements from fourth and next-generation CAR-T cells, new challenges include systemic toxicity from continuously secreted proteins, low productivity, and elevated costs. Recent research targets genetic modifications to boost killing potential, metabolic interventions to hinder tumor progression, and diverse combination strategies to enhance CAR-T cell therapy. Efforts to reduce the duration and cost of CAR-T cell therapy include developing allogenic and in-vivo approaches, promising significant future advancements. Concurrently, innovative technologies and platforms enhance the potential of CAR-T cell therapy to overcome limitations in treating solid tumors. This review explores strategies to optimize CAR-T cell therapies for solid tumors, focusing on enhancing cytotoxicity and overcoming application restrictions. We summarize recent advances in T cell subset selection, CAR-T structural modifications, infiltration enhancement, genetic and metabolic interventions, production optimization, and the integration of novel technologies, presenting therapeutic approaches that could improve CAR-T cell therapy's efficacy and applicability in solid tumors.

Atypical chemokine receptor 2 expression is directly regulated by hypoxia inducible factor-1 alpha in cancer cells under hypoxia

Lack of significant and durable clinical benefit from anti-cancer immunotherapies is partly due to the failure of cytotoxic immune cells to infiltrate the tumor microenvironment. Immune infiltration is predominantly dependent on the chemokine network, which is regulated in part by chemokine and atypical chemokine receptors. We investigated the impact of hypoxia in the regulation of Atypical Chemokine Receptor 2 (ACKR2), which subsequently regulates major pro-inflammatory chemokines reported to drive cytotoxic immune cells into the tumor microenvironment. Our in silico analysis showed that both murine and human ACKR2 promoters contain hypoxia response element (HRE) motifs. Murine and human colorectal, melanoma, and breast cancer cells overexpressed ACKR2 under hypoxic conditions in a HIF-1α dependent manner; as such overexpression was abrogated in melanoma cells expressing non-functional deleted HIF-1α. We also showed that decreased expression of ACKR2 in HIF-1α-deleted cells under hypoxia was associated with increased CCL5 levels. Chromatin immunoprecipitation data confirmed that ACKR2 is directly regulated by HIF-1α at its promoter in B16-F10 melanoma cells. This study provides new key elements on how hypoxia can impair immune infiltration in the tumor microenvironment.

Impact of 5-Flurouracil loaded chitosan nanoparticle on A375 and A431 cell line for the therapy of skin cancer

Skin cancer is an uncontrolled proliferation of abnormal skin cells that is usually caused by damaging UV radiation. Skin cancer is classified into two types: non-melanoma skin cancer and melanoma skin cancer. The entire studies focus on cytotoxic effect of prepared 5-Flurouracil loaded chitosan nanoparticle using A375 and A431 skin cancer cell line. In-vitro cell cytotoxicity assay, DAPI test of prepared formulation was conducted to observe the cytotoxic effect. The cell cytotoxicity investigation revealed that nanoparticles had higher cytotoxicity, inducing greater apoptosis within 72 h. The experimental results show that the produced nanoparticle is a good candidate for use as a 5-FU carrier in the treatment of skin cancer.

Leveraging long-acting IL-15 agonists for intratumoral delivery and enhanced antimetastatic activity

IntroductionIL-15 agonists hold promise as immunotherapeutics due to their ability to induce the proliferation and expansion of cytotoxic immune cells including natural killer (NK) and CD8+ T cells. However, they generally have short half-lives that necessitate frequent administration to achieve efficacy. To address this limitation, we have developed a half-life extension technology using hydrogel microspheres (MS). Here, the therapeutic is tethered to MSs by a releasable linker with pre-programed cleavage rates. We previously showed the MS conjugate of single-chain IL-15, MS~IL-15, effectively increased the half-life of IL-15 to approximately 1 week and enhanced the pharmacodynamics. We sought to determine whether the same would be true with a MS conjugate of the IL-15 agonist, receptor-linker IL-15 (RLI).MethodsWe prepared a long acting MS conjugate of RLI, MS~RLI. The pharmacokinetics and pharmacodynamics of MS~RLI were measured in C57BL/6J mice and compared to MS~IL-15. The antitumor efficacy of MS~RLI was measured when delivered subcutaneously or intratumorally in the CT26 tumor model and intratumorally in the orthotopic EO771 tumor model.ResultsMS~RLI exhibited a half-life of 30 h, longer than most IL-15 agonists but shorter than MS~IL-15. The shorter than expected half-life of MS~RLI was shown to be due to target-mediated-disposition caused by an IL-15 induced cytokine sink. MS~RLI resulted in very potent stimulation of NK and CD44hiCD8+ T cells, but also caused significant injection-site toxicity that may preclude subcutaneous administration. We thus pivoted our efforts toward studying the MS~RLI for long-acting intra-tumoral therapy, where some degree of necrosis might be beneficial. When delivered intra- tumorally, both MS~IL-15 and MS~RLI had modest anti-tumor efficacy, but high anti- metastatic activity.ConclusionIntra-tumoral MS~RLI and MS~RLI combined with systemic treatment with other agents could provide beneficial antitumor and anti-metastatic effects without the toxic effects of systemic IL-15 agonists. Our findings demonstrate that intra-tumorally administered long-acting IL-15 agonists counter two criticisms of loco-regional therapy: the necessity for frequent injections and the challenge of managing metastases.

Surface Coating of ZIF-8 Nanoparticles with Polyacrylic Acid: A Facile Approach to Enhance Chemical Stability for Biomedical Applications.

Nanoparticles of zeolitic imidazole framework-8 (ZIF-8 NPs), which are the subclass of metal-organic frameworks consisting of Zn ion and 2-methylimidazole, have been identified as promising drug carriers since their large microporous structure is suited for encapsulating hydrophobic drug molecules. However, one of the limitations of ZIF-8 NPs is their low stability in physiological solutions, especially in the presence of water and phosphate anions. These molecules can interact with the coordinatively unsaturated Zn sites at the external surface to induce the degradation of ZIF-8 NPs. In this study, herein a facile approach is reported to enhance the chemical stability of ZIF-8 NPs by surface coating with polyacrylic acid (PAA). The PAA-coated ZIF-8 (PAA-ZIF-8) NPs are prepared by mixing ZIF-8 NPs and PAA in water. PAA coating inhibits the degradation of ZIF-8 NPs in water as well as phosphate-buffered saline over 6 days, which seems to be due to the coordination of carboxyl groups of PAA to the reactive Zn sites. Furthermore, the PAA-ZIF-8 NPs loaded with the anticancer drug doxorubicin (Dox) show cytotoxicity in human colon cancer cells. These results clearly show the feasibility of the PAA coating approach to improve the chemical stability of ZIF-8 NPs without impairing their drug delivery capability.

Synthesis and Evaluation of a ZnO-Chitosan Adduct for Safe and Sustainable Enhanced Ultra-Violet (UV) Sunscreens Protection.

Chitosan (Ch), a natural polysaccharide, is known for its biocompatibility, biodegradability, and various beneficial properties, including antioxidant and antibacterial activities. The objective of this study is to investigate the functionalization of zinc oxide (ZnO) with chitosan to develop a novel ZnO@Ch adduct for use in cosmetic formulations, specifically as a sun protection agent. The functionalization was achieved through ionotropic gelation, which enhanced the stability and reduced the photocatalytic activity of ZnO, thereby improving its safety profile for skin applications. FTIR spectroscopy confirmed the successful functionalization, while TGA and DSC characterized the thermal properties and stability. The Zeta potential and particle size analyses demonstrated improved stability of ZnO@Ch across various pH levels compared to uncoated ZnO. The structure of the obtained adduct was also confirmed by SEM analysis. The ZnO@Ch adduct exhibited enhanced stability at neutral and slightly alkaline pH values, reduced photocatalytic activity compared to pure ZnO, and had lower cytotoxicity in 3T3 cells compared to pure ZnO, particularly at higher concentrations. The ZnO@Ch adduct provided a higher Sun Protection Factor (SPF) and UVA Protection Factor (UVA-PF) than pure ZnO, indicating enhanced UV protection. The adduct's ability to provide higher SPF at lower ZnO concentrations offers economic and environmental benefits, aligning with sustainable product design principles. Future studies will focus on optimizing the formulation and testing the efficacy and safety at higher concentrations to fully realize its potential as a natural, eco-friendly sunscreen ingredient.

Azobenzene-Tagged Photopeptides Exhibiting Excellent Selectivity and Light-Induced Cytotoxicity in MCF-7 Cells over HeLa and A549.

The precise regulation of proteasome activity has become a focal point in current research, particularly its implications in cancer treatment. Bortezomib is used for treating multiple myeloma and is found to be ineffective against solid tumors. A spatiotemporal control over the proteasome is one of the solutions to resolve these issues using external stimuli, such as light. Thus, we designed and synthesized azobenzene-containing tripeptide vinyl sulfones 1, 2, 3, and 4, as the azobenzene moiety can impart E↔Z isomerism upon exposure to UV light. Further, the hydrophobicity of these peptides was fine-tuned by systematically varying the size of hydrophobic amino acids at the P1, P2, and P3 positions. The light-induced Z isomers of these photopeptides showed excellent cellular potency in HeLa, MCF-7, and A549 cell lines. Photopeptide 4 with valine at the proximal position, phenylalanine at P2, and leucine at the P1 positions exhibited 19.3- and 6.6-fold cellular potency in MCF-7 and A549 cells, respectively.

Efficient directional biosynthesis of isoquercitrin from quercetin by Bacillus subtilis CD-2 and its anti-inflammatory activity

Isoquercetin, as the sole product, was directionally biosynthesized from quercetin in a non-aqueous system using Bacillus subtilis CD-2 (1 g/L quercetin), and its structure was identified by LC-MS and NMR analysis. CCK8 assays showed no cytotoxicity and good cell proliferation. The anti-inflammatory experiments demonstrated strong inhibition of NO release, transcriptional downregulation of classical effective cellular factors tumour necrosis factor-α, interleukin-6, interleukin-1β, and transcriptional upregulation of interleukin-10 in LPS-induced RAW264.7 cells. Its stronger anti-inflammatory activity than quercetin provided a reference for modifying the structure of quercetin to obtain more compounds with better pharmacological activities for medical industry.

Kinetics of viral hemorrhagic septicemia virus (VHSV) and immune response in olive flounder (Paralichthys olivaceus) at altered temperature

Viral hemorrhagic septicemia virus (VHSV) is a pathogen that causes hemorrhagic septicemia in olive flounder at water temperatures below 15 °C, leading to symptoms such as abdominal swelling due to ascites and muscle hemorrhaging, and in severe cases, mortality. In this study, we investigated the proliferation of NCCs, the transcriptional analysis of CD4 and CD8, and the expression of pro-inflammatory cytokines (IL-1β, IL6, TNFα) and the cytokines (IL12, IL15, IFN-1β, IFNγ) involved in cytotoxic cell activation in the kidney of olive flounder during VHSV infection at suboptimal temperature (17 °C) and following a shift to optimal temperature (10 °C). Following viral infection, the population of NCCs and CD8 gene expression steadily increased. Meanwhile, IL12, IL15, and IFN-1β levels exhibited an early surge, reaching their peak within 1–2 days post-challenge at 17 °C. Notably, in olive flounder that were re-challenged with VHSV at 10 °C after an initial challenge at 17 °C, there was a rapid and robust expansion of NCCs and increased CD4 and CD8 gene expression, demonstrating the mounting of immune memory by NCCs and an efficient adaptive immune response from CD4+ and CD8+ T cells against VHSV infection.

Suppression of non-muscle myosin II boosts T cell cytotoxicity against tumors.

Increasing evidence highlights the importance of immune mechanoregulation in establishing and sustaining tumor-specific cytotoxicity required for desirable immunotherapeutic outcomes. However, the molecular connections between mechanobiological inputs and outputs and the designated immune activities remain largely unclear. Here, we show that partial inhibition of non-muscle myosin II (NM II) augmented the traction force exerted by T cells and potentiated T cell cytotoxicity against tumors. By using T cells from mice and patients with cancer, we found that NM II is required for the activity of NKX3-2 in maintaining the expression of ADGRB3, which shapes the filamentous actin (F-actin) organization and ultimately attributes to the reduced traction force of T cells in the tumor microenvironment. In animal models, suppressing the NM II-NKX3-2-ADGRB3 pathway in T cells effectively suppressed tumor growth and improved the efficacy of the checkpoint-specific immunotherapy. Overall, this work provides insights into the biomechanical regulation of T cell cytotoxicity that can be exploited to optimize clinical immunotherapies.

Targeted therapy of multiple myeloma by IL21-NKG2D CAR-T cells.

NKG2D chimeric antigen receptor (CAR)-modified T cells (NKG2D CAR-T cells) have been reported to be preclinically efficient in several tumors, but little is known whether NKG2D CAR-T cells co-expressing IL21 (IL21-NKG2D CAR-T cells) display greater antitumor activity in multiple myeloma (MM). In this study, the lentivirus has been produced for expression of the IL21 sequence linked to the extracellular NKG2D sequence with the signal peptide linked through the CD8α hinge-transmembrane domain to the 4-1BB molecule fused with the CD3-ζ chain signaling domain, and the engineered IL21-NKG2D CAR-T cells and NKG2D CAR-T cells were constructed. The CAR expression on CAR-T cells was assessed by flow cytometry, and the killing effects of CAR-T cells on MM were assessed by the cytotoxicity assay and ELISA assay. Moreover, xenograft models were also established to evaluate the ability of IL21-NKG2D-CAR-T cells to eliminate MM in vivo. Our results indicated that NKG2D CAR-T cells had dramatic cytotoxicity on MM cells in vitro, and co-expression of IL-21 significantly increased the cytotoxicity of NKG2D CAR-T cells on MM cells. Remarkably, we found that dexamethasone enhanced the cytotoxicity of IL21-NKG2D CAR-T cells on MM cells. Furthermore, IL21-NKG2D CAR-T cells also displayed significant anti-myeloma activity in vivo. In conclusion, IL21-NKG2D CAR-T cells had dramatic cytotoxicity on MM cells in vitro and in vivo, and a system to apply IL21-NKG2D CAR-T cells and low dosage of dexamethasone for the future study of the targeted therapy for MM has been established.

Effect of Acacia concinna Extract on Apoptosis Induction Associated with Endoplasmic Reticulum Stress and Modulated Intracellular Signaling Pathway in Human Colon HCT116 Cancer Cells.

Colorectal cancer (CRC) stands as one of the most prevalent cancer types and among the most frequent causes of cancer-related death globally. Acacia concinna (AC) is a medicinal and edible plant that exhibits a multitude of biological properties, including anticancer properties. This study aimed to investigate the impact of the AC extract on apoptosis induction and the underlying mechanisms associated with this effect in KRAS-mutated human colon HCT116 cells. The effect of AC extract on cell cytotoxicity was evaluated using MTT assay. Nuclear morphological changes were visualized with Hoechst 33342 staining, while mitochondrial membrane potential (MMP) was assessed via JC-1 staining. Flow cytometry was employed for cell cycle analysis, and intracellular ROS levels were determined using DCFH-DA staining. The results showed that HCT116 cells exposed to AC extract showed reduced cell growth and prompted apoptosis, as indicated by an increase in chromatin condensation, apoptotic bodies, the sub-G1 apoptotic cell population, and disrupted MMP. Expression levels of apoptosis mediator proteins determined by Western blot analysis showed an increase in pro-apoptotic proteins (Bak and Bax) while decreasing anti-apoptotic proteins (Bcl-2, Bcl-xL, and Mcl-1), leading to caspase-7 activation and PARP inactivation. AC extract was also found to enhance intracellular reactive oxygen species (ROS) levels and stimulate endoplasmic reticulum (ER) stress. Furthermore, AC extract increases the phosphorylation of ERK1/2, p38, and c-Jun while downregulating PI3K, Akt, β-catenin, and their downstream target proteins. These results demonstrate that AC extract could inhibit cancer cell growth via ROS-induced ER stress associated with apoptosis and regulate the MAPK, PI3K/Akt, and Wnt/β-catenin signaling pathways in HCT116 cells. Therefore, AC extract may be a novel candidate for natural anticancer resources for colon cancer treatment.

Insight into Antiviral Activity of Ag/TiO2 Nanocomposites Against Influenza H1N1 Virus and Its Antiviral Mechanism.

Synthesis and characterization of silver (Ag)/titanium dioxide (TiO2) nanocomposite (ATA) to investigate its antiviral activity against the H1N1 influenza virus and antiviral mechanisms. A water-dispersible ATA was prepared by a photocatalytic reduction process from AgNO3 and TiO2. The characterization of ATA was performed by ultraviolet-visible spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy. The antiviral activities and the antiviral mechanism of ATA were investigated in detail by light microscopy, transmission electron microscopy and biological techniques such as cell cytotoxicity, 50% tissue culture infectious dose detection, western blot and reverse transcription-polymerase chain reaction. These results showed the successful synthesis of ATA nanocomposite with uniform particle size and distribution. It demonstrated the highly efficient antiviral activity of ATA in a dose- and time-dependent manner, as indicated by the reduction of viral titer and the reduction of cytopathic effects caused by viral infection. In the presence of ATA, the structure of the H1N1 influenza virus is directly destroyed and even disintegrated, with the damaged surface membrane proteins and fuzzy contour. It reduces the infection efficiency of influenza by suppressing the activity and expression of hemagglutinin and neuraminidase. The results of mechanistic studies suggested that ATA nanocomposite primarily interferes with virus attachment to viral receptors on the cell surface. Our study suggests that ATA may be a good antiviral candidate against the influenza virus. Compared with AgNPs alone, our synthesized ATA nanocomposites can achieve similar viral inactivation rates using only a much smaller concentration of AgNPs, greatly reducing the amount of AgNPs and their potential side effects. It has great practical value for attaching ATA to the high-efficiency particulate air network in the air purifier, which can kill the virus attached to it and limit its spread.

Identification of PSMD2 as a promising biomarker for pancreatic cancer patients based on comprehensive bioinformatics and in vitro studies

BackgroundPancreatic cancer patients have limited treatment options and extremely poor prognosis. Dysregulations of proteasome 26S subunit, non-ATPases (PSMDs) contribute to the development of various cancers, whereas the significance of PSMDs in pancreatic cancer is poorly understood. In the present study, we intended to explore the therapeutic potential of PSMDs in pancreatic cancer. MethodsBased on TCGA database, the expression of PSMDs was analyzed in pancreatic cancer patients. Multivariate Cox regression and Kaplan–Meier survival analyses were conducted to investigate the prognostic value of PSMDs. The correlations between the expression of PSMD2/14 and immune cell infiltration, immune checkpoint genes’ expression, enrichment of signaling pathways, and the sensitivity of chemotherapies were also evaluated. Knockdown and overexpression experiments were performed to explore the biological function of PSMD2/14. Immunoblotting was conducted to detect the downstream signaling pathway of PSMD2. ResultsMost of the PSMDs, except for PSMD5 and PSMD6, were significantly upregulated in pancreatic cancer tissues. Patients with higher grade tumor had increased mRNA levels of PSMD1/2/5/7/8/11/12/14. Survival and multivariate Cox regression analyses indicated that PSMD2 and PSMD14 were biomarkers of worse prognosis. High expression of PSMD2 and PSMD14 was positively correlated with the levels immune checkpoint genes but not with the infiltration of specific immune cell types. In vitro knockdown of PSMD2, but not PSMD14, increased the apoptosis, gemcitabine’s toxicity and inhibited the growth capacity of MIA cells. Conversely, decreased apoptosis and gemcitabine sensitivity along with accelerated cell proliferation ability were observed in PSMD2-overexpressing PANC-1 cells. Mechanistically, PSMD2 activated the AKT/mTOR signaling pathway, consistent with the findings from KEGG and GSEA analysis. The AKT specific inhibitor MK-2206 exhibited higher cytotoxicity in MIA and PANC-1 cells with high PSMD2 expression. Importantly, MK-2206 largely reversed the oncogenic functions of PSMD2 on the growth and proliferation of PANC-1 cells. ConclusionIn summary, our study provided a comprehensive bioinformatics analysis of PSMDs in pancreatic cancer. We identified that PSMD2 acted as a tumor-promoting protein in pancreatic cancer through the activation of the AKT/mTOR pathway. The overexpression of PSMD2 may be a potential biomarker that predicts the response of pancreatic cancer patients to AKT inhibitor treatments.

Green approach of cobalt sulfide nanoparticles from novel red stigma of Crocus sativus and multifaceted biomedical advancement

The present study was based on green protocols for synthesizing cobalt sulfide nanoparticles using saffron stigma flower extract (Crocus sativus), as saffron is considered a potent traditional medicine. Furthermore, the novel cobalt sulfide (CoS) nanoparticles prepared by the green approach for the first time with saffron improved showed cytotoxicity and antibacterial activity, as well as significant antitumor activity of Hela, A549, and MCF 7 cells viz in vitro studies. The saffron-cobalt sulfide nanoparticles underwent characterization using various techniques which include the X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Advances in scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HR-TEM), and the energy dispersive X-ray analysis spectroscopy. Both XRD, and FTIR confirmed the synthesis of pure cobalt sulfide nanoparticles. The resulting saffron-based cobalt sulfide nanoparticles exhibited a nanosphere structure, as confirmed by HRTEM, indicating the formation of nanosphere and microstructures. In vitro studies were conducted to assess the cytotoxicity and cell viability of Hela cells, A549, and MCF-7 cells. And, antibacterial studies were performed against various bacterial strains using different concentrations of cobalt sulfide nanoparticles derived from the red stigma of saffron (Crocus sativus) only the red stigma extract. The MTT assay analysis, cell viability, and morphological studies demonstrated the cytotoxic studies of the synthesized cobalt sulfide nanoparticles on cancer cells. The antibacterial test of the nanoparticles was also evaluated, revealing significant zones of inhibition (mm) against pathogens and cobalt sulfide nanoparticles using saffron extract, showcasing their potent cytotoxic, antibacterial, and antitumor activities with promising biomedical applications.

Potential treatment approaches for malignant peritoneal mesothelioma: in vivo and in vitro experimental study of natural killer cell immunotherapy.

Malignant peritoneal mesothelioma (MPM) is a rare primary malignant tumor with an extremely poor prognosis that currently lacks effective treatment options. This study investigated the in vitro and in vivo efficacy of natural killer (NK) cells for treatment of MPM. An in vitro study was conducted to assess the cytotoxicity of NK cells from umbilical cord blood to MPM cells with the use of a high-content imaging analysis system, the Cell Counting Kit-8 assay, and Wright-Giemsa staining. The level of NK cell effector molecule expression was detected by flow cytometry and enzyme-linked immunosorbent assays. The ability of NK cells to kill MPM cells was determined based on live cell imaging, transmission electron microscopy, and scanning electron microscopy. An in vivo study was conducted to assess the efficacy and safety of NK cell therapy based on the experimental peritoneal cancer index, small animal magnetic resonance imaging, and conventional histopathologic, cytologic, and hematologic studies. NK cells effectively killed MPM cells through the release of effector molecules (granzyme B, perforin, interferon-γ, and tumor necrosis factor-α) in a dose- and density-dependent manner. The NK cell killing process potentially involved four dynamic steps: chemotaxis; hitting; adhesion; and penetration. NK cells significantly reduced the tumor burden, diminished ascites production, and extended survival with no significant hematologic toxicity or organ damage in NOG mice. NK cell immunotherapy inhibited proliferation of MPM cells in vitro and in vivo with a good safety profile.

Quercetin exhibits cytotoxicity in cancer cells by inducing two-ended DNA double-strand breaks.

Quercetin, a flavonoid, is involved in the induction of DNA double-strand breaks (DSBs), in addition to its antioxidant properties. Although DNA topoisomerase II (Top2) and reactive oxygen species (ROS) have been suggested as possible mechanisms through which quercetin induces DSBs, the exact mechanism remains unclear. In this study, we examined the mechanism of DSB induction by quercetin and its repair using HeLa cells and gene-knockout cell lines generated from human Nalm-6cells. Immunofluorescence staining for γH2AX, a DSB marker, and analysis of the frequency of random integration of foreign DNA, which correlates with the number of DSBs and DSB repair pathways, indicated that quercetin induces DSBs in a concentration-dependent manner. The sensitivity assay suggested that the factor involved in quercetin-induced DSBs was not Top2. However, ROS was found to accumulate transiently in quercetin-treated HeLa cells. Furthermore, the addition of ascorbic acid increased the survival of quercetin-treated HeLa cells, suggesting that quercetin induces a transient accumulation of ROS, which in turn induces DSBs. The resulting DSBs were repaired primarily by non-homologous end-joining and homologous recombination, similar to X-ray-induced DSBs. Taken together, quercetin, used as a radiomimetic agent, has the potential to produce effects equivalent to those of an X ray-dose at a relatively low risk.

Metabolic programs drive function of therapeutic NK cells in hypoxic tumor environments.

Limited oxygen (hypoxia) in solid tumors poses a challenge to successful immunotherapy with natural killer (NK) cells. NK cells have impaired cytotoxicity when cultured in hypoxia (1% oxygen) but not physiologic (>5%) or atmospheric oxygen (20%). We found that changes to cytotoxicity were regulated at the transcriptional level and accompanied by metabolic dysregulation. Dosing with interleukin-15 (IL-15) enhanced NK cell cytotoxicity in hypoxia, but preactivation with feeder cells bearing IL-21 and 4-1BBL was even better. Preactivation resulted in less perturbed metabolism in hypoxia; greater resistance to oxidative stress; and no hypoxia-induced loss of transcription factors (T-bet and Eomes), activating receptors, adhesion molecules (CD2), and cytotoxic proteins (TRAIL and FasL). There remained a deficit in CD122/IL-2Rβ when exposed to hypoxia, which affected IL-15 signaling. However, tri-specific killer engager molecules that deliver IL-15 in the context of anti-CD16/FcγRIII were able to bypass this deficit, enhancing cytotoxicity of both fresh and preactivated NK cells in hypoxia.

Discovery of a new lead molecule to develop a novel class of human factor XIIa inhibitors.

Factor XIIa (FXIIa) is a plasma serine protease within the contact activation pathway. Inhibiting FXIIa could offer a viable therapeutic approach for achieving effective and safer anticoagulation without the bleeding risks that accompany the use of existing anticoagulants. Therefore, we investigated the anticoagulant properties of an amidine-containing molecule (inhibitor 1) to identify a potential lead molecule for subsequent development of FXIIa inhibitors. Results indicated that inhibitor 1 primarily inhibits human FXIIa with an IC50 value of ~30 µM. The inhibitor demonstrated variable selectivity against thrombin, factor IXa, factor Xa, factor XIa, and activated protein C. Michaelis-Menten kinetics indicated that the molecule is an active site inhibitor of FXIIa. Molecular modeling studies revealed that the molecule recognizes residues His57, Asp189, and Ala190 in FXIIa's active site. The inhibitor selectively and concentration-dependently prolonged the clotting time of human plasma under activated partial thromboplastin time assay conditions. The inhibitor did not exhibit significant cytotoxicity in human HEK293 cells and the in silico pharmacokinetics and toxicology data were comparable to known anticoagulants. This study introduces inhibitor 1 as a lead platform for further development as an anticoagulant to provide a more effective and safer approach to preventing and treating thromboembolic diseases.