Tumoricidal Activity Research Articles

Targeting thymidine phosphorylase alleviates resistance to dendritic cell immunotherapy in colorectal cancer and promotes antitumor immunity.

T-cell exhaustion plays a pivotal role in the resistance of microsatellite-stable colorectal cancer (CRC) to immunotherapy. Identifying and targeting T-cell exhaustion-activating mechanisms is a promising strategy to augment the effects of immunotherapy. Here, we found that thymidine phosphorylase (TYMP) plays a decisive role in inducing systemic T-cell exhaustion and abrogating the efficacy of dendritic cell (DC) therapy in a CRC model. Targeting TYMP with tipiracil hydrochloride (TPI) induces immunological cell death (ICD). The combined effects of TPI and imiquimod-activated DCs turn CT26 tumors into immunologically ‘hot’ tumors by inducing ICD in vivo. High-dimensional cytometry analysis revealed T-cell and IFN-γ dependency on the therapeutic outcome. In addition, chemoimmunotherapy converts intratumoral Treg cells into Th1 effector cells and eliminates tumor-associated macrophages, resulting in higher cytotoxic T lymphocyte infiltration and activation. This effect is also associated with the downregulation of PD-L1 expression in tumors, leading to the prevention of T-cell exhaustion. Thus, cooperative and cognitive interactions between dendritic cells and immunogenic cell death induced by therapy with TPI promote the immune response and tumoricidal activities against microsatellite stable colorectal cancer. Our results support TYMP targeting to improve the effects of DC immunotherapy and outcomes in CRC.

αvβ3 integrin-specific exosomes engineered with cyclopeptide for targeted delivery of triptolide against malignant melanoma

BackgroundMelanoma is the most malignant skin tumor and is difficult to cure with the alternative treatments of chemotherapy, biotherapy, and immunotherapy. Our previous study showed that triptolide (TP) exhibited powerful tumoricidal activity against melanoma. However, the clinical potential of TP is plagued by its poor aqueous solubility, short half-life, and biotoxicity. Therefore, developing an ideal vehicle to efficiently load TP and achieving targeted delivery to melanoma is a prospective approach for making full use of its antitumor efficacy.ResultsWe applied exosome (Exo) derived from human umbilical cord mesenchymal stromal cells (hUCMSCs) and engineered them exogenously with a cyclic peptide, arginine-glycine-aspartate (cRGD), to encapsulate TP to establish a bionic-targeted drug delivery system (cRGD-Exo/TP), achieving synergism and toxicity reduction. The average size of cRGD-Exo/TP was 157.34 ± 6.21 nm, with a high drug loading of 10.76 ± 1.21%. The in vitro antitumor results showed that the designed Exo delivery platform could be effectively taken up by targeted cells and performed significantly in antiproliferation, anti-invasion, and proapoptotic activities in A375 cells via the caspase cascade and mitochondrial pathways and cell cycle alteration. Furthermore, the biodistribution and pharmacokinetics results demonstrated that cRGD-Exo/TP possessed superior tumor targetability and prolonged the half-life of TP. Notably, cRGD-Exo/TP significantly inhibited tumor growth and extended survival time with negligible systemic toxicity in tumor-bearing mice.ConclusionThe results indicated that the functionalized Exo platform provides a promising strategy for targeted therapy of malignant melanoma.Graphical

Robust boron nanoplatform provokes potent tumoricidal activities via inhibiting heat shock protein

Near-infrared (NIR)-light-triggered photothermal therapy (PTT) is a promising treatment for breast cancer. However, its therapeutic efficiency is often compromised due to the heat-induced up-regulation of heat shock proteins, which confer photothermal resistance. To solve this urgent problem, PEGylated two-dimensional boron nanosheets (B-PEG)—which allow both multimodal imaging and photothermal conversion—were loaded with gambogic acid (GA), which can inhibit heat shock protein 90 (Hsp90). Experimental findings indicated that this combination of B-PEG and GA could serve as an integrated drug delivery system for cancer diagnosis and treatment. It could be used to administer mild PTT as well as chemotherapy for breast cancer, provide improved anti-tumor effects, and reduce the toxicity of PTT, all while inhibiting breast cancer growth. This drug delivery system could offer a novel tool for administering chemotherapy combined with PTT while avoiding the adverse effects of traditional PTT.

Activation of nano-photosensitizers by Y-90 microspheres to enhance oxidative stress and cell death in hepatocellular carcinoma

While radioembolization with yttrium-90 (Y-90) microspheres is a promising treatment for hepatocellular carcinoma (HCC), lower responses in advanced and high-grade tumors present an urgent need to augment its tumoricidal efficacy. The purpose of this study was to determine whether clinically used Y-90 microspheres activate light-responsive nano-photosensitizers to enhance hepatocellular carcinoma (HCC) cell oxidative stress and cytotoxicity over Y-90 alone in vitro. Singlet oxygen and hydroxyl radical production was enhanced when Y-90 microspheres were in the presence of several nano-photosensitizers compared to either alone in cell-free conditions. Both the SNU-387 and HepG2 human HCC cells demonstrated significantly lower viability when treated with low activity Y-90 microspheres (0.1–0.2 MBq/0.2 mL) and a nano-photosensitizer consisting of both titanium dioxide (TiO2) and titanocene (TC) labelled with transferrin (TiO2-Tf-TC) compared to Y-90 microspheres alone or untreated cells. Cellular oxidative stress and cell death demonstrated a linear dependence on Y-90 at higher activities (up to 0.75 MBq/0.2 mL), but was significantly more accentuated in the presence of increasing TiO2-Tf-TC concentrations in the poorly differentiated SNU-387 HCC cell line (p < 0.0001 and p = 0.0002 respectively) but not the well-differentiated HepG2 cell line. Addition of TiO2-Tf-TC to normal human hepatocyte THLE-2 cells did not increase cellular oxidative stress or cell death in the presence of Y-90. The enhanced tumoricidal activity of nano-photosensitizers with Y-90 microspheres is a potentially promising adjunctive treatment strategy for certain patient subsets. Applications in clinically relevant in vivo HCC models are underway.

787 Endosomal GLUT3 is essential for macrophage signaling, polarization, and function in wound healing and atopic dermatitis

Macrophages are immune cells that play critical roles in both inflammation and tissue homeostasis. Classically activated (M1) macrophages promote antimicrobial and tumoricidal activity, while alternatively activated (M2) macrophages promote phagocytosis and tissue homeostasis. The facilitative GLUT1 and GLUT3 hexose transporters are expressed abundantly in different hematopoietic lineages, but their specific roles in macrophages, and leukocytes in general is poorly understood. We discovered that GLUT3 expression was increased after M2-activation stimuli in macrophages.

P865: BIOMARKER ANALYSIS TO SUPPORT DOSE OPTIMIZATION OF IBERDOMIDE AS MONOTHERAPY AND IN COMBINATION WITH STANDARD OF CARE TREATMENTS FOR MULTIPLE MYELOMA FROM A PHASE 1/2 TRIAL

Background: Iberdomide (IBER), a novel cereblon E3 ligase modulator (CELMoD®) compound, induces ubiquitination and proteasome-dependent degradation of Ikaros and Aiolos proteins, resulting in tumoricidal and immunomodulatory activity in multiple myeloma (MM). IBER is being investigated for the treatment of relapsed/refractory MM (RRMM) in a phase 1/2 study (NCT02773030). Due to the recent focus by health authorities on dose selection for oncology products other than the maximum tolerated dose (MTD), a comprehensive analysis of pharmacodynamics (PD) and pharmacokinetics (PK) was implemented to support dose optimization of IBER. Aims: To inform dose selection of IBER as monotherapy, and in combination with dexamethasone (DEX; Iber+d) and with DEX and daratumumab (DARA; IberDd). Methods: PK samples were collected on treatment of cycles (C) 1–4 to estimate IBER exposure using population PK (area under the concentration curve over 24-h dosing interval [AUCτ]). Biomarkers included analysis of peripheral blood samples on C1 day (D)1 and mid-cycle through C4 for immunophenotyping, absolute neutrophil counts (ANC), and assessment of serum free light chain (sFLC), as a biomarker of tumor burden. Bone marrow samples were collected at screening and C2D15 for immunohistochemistry. Results: IBER AUCτ increased in a dose-proportional manner between 0.3 and 1.0 mg as monotherapy and 0.3 and 1.6 mg in combination with DEX, with moderate variability. Median time to maximum serum concentration of IBER was 2–4 h post dose with an elimination half-life of ~12 h. Comparable IBER exposure was observed between monotherapy and Iber+d. Reductions in Ikaros/Aiolos protein levels in tumor cells were observed at all dose levels in both cohorts with a >90% reduction at the 0.45-mg dose. However, a >50% decrease in sFLCs was observed only at doses ≥0.9 mg, and doses of 1.6 mg induced faster and deeper decreases vs lower doses. In the immune compartment, IBER treatment induced similar dose-/exposure-dependent PD changes as monotherapy and Iber+d, which appeared to saturate at higher doses. A >80% reduction in mature B cells and ~2-fold increase in proliferating/activated T and NK cells were observed at doses ≥1.0 mg. PD activity of IBER was not attenuated by prior refractoriness to immunomodulatory drugs (IMiD® agents) or anti-CD38 therapy. Based on these results, doses between 1.0 and 1.6 mg were tested in the IberDd cohort. PK and PD of IBER were similar with concomitant administration of DARA. In this cohort, a reduction in mature B cells and sFLCs was more consistently observed at 1.6 mg vs lower doses; however, higher IBER exposures were associated with more pronounced decreases in ANC when compared with Iber+d. This was clinically manageable and the MTD of IBER was not determined in any cohort. Summary/Conclusion: Similar PK and PD results were observed in patients treated with IBER monotherapy, Iber+d, and IberDd. Across all cohorts, a >20% difference in dose was needed for meaningful change in IBER exposure, immune PD began to saturate at doses ≥1.0 mg, and decreases in tumor burden were greatest at the 1.6-mg dose. Based on these results, IBER doses of 1.0, 1.3, and 1.6 mg were chosen for dose optimization of IberDd for RRMM. Taken together with data suggesting immune surveillance is a driver of maintenance therapy efficacy and a desire to increase IBER tolerability with long-term treatment, doses of 0.75, 1.0, and 1.3 mg were selected for dose optimization of IBER monotherapy in the newly diagnosed MM maintenance setting.

Targeting Inhibition of Accumulation and Function of Myeloid-Derived Suppressor Cells by Artemisinin via PI3K/AKT, mTOR, and MAPK Pathways Enhances Anti-PD-L1 Immunotherapy in Melanoma and Liver Tumors.

Despite the remarkable success and efficacy of immune checkpoint blockade (ICB) therapy such as anti-PD-L1 antibody in treating cancers, myeloid-derived suppressor cells (MDSCs) that lead to the formation of the protumor immunosuppressive microenvironment are one of the major contributors to ICB resistance. Therefore, inhibition of MDSC accumulation and function is critical for further enhancing the therapeutic efficacy of anti-PD-L1 antibody in a majority of cancer patients. Artemisinin (ART), the most effective antimalarial drug with tumoricidal and immunoregulatory activities, is a potential option for cancer treatment. Although ART is reported to reduce MDSC levels in 4T1 breast tumor model and improve the therapeutic efficacy of anti-PD-L1 antibody in T cell lymphoma-bearing mice, how ART influences MDSC accumulation, function, and molecular pathways as well as MDSC-mediated anti-PD-L1 resistance in melanoma or liver tumors remains unknown. Here, we reported that ART blocks the accumulation and function of MDSCs by polarizing M2-like tumor-promoting phenotype towards M1-like antitumor one. This switch is regulated via PI3K/AKT, mTOR, and MAPK signaling pathways. Targeting MDSCs by ART could significantly reduce tumor growth in various mouse models. More importantly, the ART therapy remarkably enhanced the efficacy of anti-PD-L1 immunotherapy in tumor-bearing mice through promoting antitumor T cell infiltration and proliferation. These findings indicate that ART controls the functional polarization of MDSCs and targeting MDSCs by ART provides a novel therapeutic strategy to enhance anti-PD-L1 cancer immunotherapy.

Abstract 2753: Interleukin-10 and transforming growth factor-beta do not suppress tumor killing activity of PBMC-derived SUPLEXA cells

Abstract Introduction: SUPLEXA cells are peripheral blood mononuclear cells (PBMCs) being developed by Alloplex Biotherapeutics as an autologous adoptive therapy for cancer. The novel nature of SUPLEXA cells is that they are developed from peripheral blood mononuclear cells (PBMCs) that have been activated and expanded by engineered leukocyte stimulator cell lines (ENLIST cells), which are melanoma cell lines that express immunomodulatory proteins to program the tumor killing phenotype of SUPLEXA cells. We find that the SUPLEXA cell manufacturing process reproducibly results in a mixture of NK cells, CD8 T cells, and γδ T cells with broad tumor cell killing activity. In this study, we evaluated the effects of two major immunosuppressive cytokines found in the tumor microenvironment (IL-10 and TGF-β) on the tumor cytolytic function and cytokine release by SUPLEXA cells. Results: SUPLEXA cells were prepared by a 14-day process of PBMC induction by ENLIST cells for 5 days followed by 9 days expansion in cytokines. SUPLEXA cell mediated tumor cytolytic assays using red fluorescent protein (RFP) expressing M14 melanoma cells as targets were performed in the absence or presence of IL-10 or TGF-β (1.25 - 10 ng/ml). Cytokine levels in 48-hour culture supernatants from cytolytic reactions and SUPLEXA or M14 target cells alone were measured using a 36-plex Luminex assay. Without cytokine addition, SUPLEXA mediated cytolysis was 47.3% at 8:1 and 30.9% at 4:1 effector to target (E:T) ratios. Significant increases in SUPLEXA cell tumoricidal activity was observed with addition of IL-10 (74.3% at 8:1 and 51.7% at 4:1 E:T ratios at 2.5 ng/ml IL-10 added, P &amp;It 0.001 by two-way ANOVA). Adding TGF-β caused a reduction in cytolytic activity that was not significant (36.5% at 8:1 and 20.8% at 4:1 E:T ratios with 2.5 ng/ml TGF-β added). Supernatants from cytolysis assays showed that SUPLEXA cells produced IFNγ, MIP-1α, RANTES, IL-8, Gro-α, MIG, and IP-10 in response to tumor cells. IL-10 significantly augmented IFNγ, RANTES, and MIP-1α production by SUPLEXA cells in a dose-dependent fashion. In contrast, TGF-β reduced IFNγ, MIP-1α, Gro-α, RANTES, and IP-10 production, but increased IL-8 production by SUPLEXA cells. Conclusions: An in vitro approach was used as a surrogate for what might occur in patients with solid tumors to test whether potent immune suppressive cytokines that are present in the tumor microenvironment might inhibit SUPLEXA cell function. Our findings indicate that IL-10 and TGF-β do not significantly reduce the tumor killing activity of SUPLEXA cells. Instead, we discovered that IL-10 significantly enhances SUPLEXA cell function and cytokine production, which suggests that SUPLEXA cells may acquire heightened tumoricidal activity and promote immune surveillance by augmenting cytokine and chemokine levels within the tumor microenvironment when given therapeutically to cancer patients. Citation Format: Frank Borriello, Joshua W. Keegan, James A. Lederer. Interleukin-10 and transforming growth factor-beta do not suppress tumor killing activity of PBMC-derived SUPLEXA cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2753.

Abstract 2067: NL-201, a de novo engineered IL2/IL15 mimic, synergizes with radiation to generate potent antitumor immunity

Abstract There is a growing interest in combining radiotherapy (RT), a standard of care treatment for many cancer types, with immunotherapeutic agents to improve efficacy. One such approach is RT in combination with high-dose recombinant interleukin 2 (IL-2), which elicits anti-tumor immune responses by stimulating T-cell and NK cell populations. Although effective for some patients, the overall clinical benefit of high-dose recombinant IL-2 is limited by toxicity and the expansion of regulatory T cells (Tregs) through signaling events mediated by IL2RΑ (CD25). In this study, we examined RT in combination with NL-201, a highly potent and stable CD25-independent IL-2 and IL-15 receptor agonist with enhanced affinity for IL2RΒ and IL2RΓ. Single-agent NL-201 was well-tolerated in mice, yielded tumoricidal activity, expanded peripheral T cells, and enhanced the infiltration of effector T cells and dendritic cells (DCs) into murine breast cancers. In combination with RT, NL-201 enhanced activation of the cytosolic DNA sensor cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway, resulting in increased type I interferon (IFN) production in DCs and, consequently, greater tumor infiltration by T cells and more efficient priming of antigen-specific T cells by professional antigen-presenting cells (APCs). The immune stimulatory mechanisms triggered by the NL-201 and RT combination resulted in superior tumor growth inhibition and survival benefit in both localized and metastatic murine breast cancers, including those spread to the central nervous system. Genetic knockout of STING in host cells abrogated the activity of the NL-201 and RT combination, thus confirming the crucial role of innate immune sensors in the combination treatment’s antitumor responses. Additionally, when combined with PD-1 antibodies, NL-201 significantly improved growth inhibition of metastatic breast cancers that were previously resistant to checkpoint blockade. We demonstrated that the CD25-independent IL-2 and IL-15 receptor agonist, NL-201, in combination with RT is well-tolerated and elicits robust anti-tumor activity through both innate and adaptive responses, including in checkpoint resistant tumors and brain metastases. Furthermore, we identify a unique mechanism in which NL-201 synergizes with RT, likely via the direct activation of STING in DCs. Taken together, the results provided herein support further preclinical and clinical investigation of this novel combination regimen in both localized and metastatic settings. Citation Format: Xuefeng Li, Kristin Huntoon, Yifan Wang, Carl Walkey, Betty Y. Kim, Wen Jiang. NL-201, a de novo engineered IL2/IL15 mimic, synergizes with radiation to generate potent antitumor immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2067.

Study to determine the effectiveness of dietary supplementation in pediatric patients with nutritional and health concerns

Aim: The study's main objective was to see whether the well-known probiotic Bifidobacterium lactis might aid in the development of children. Method: A nine-week clinical study involving 400 children aged between 5 to 10 years, was conducted to evaluate the efficacy of food supplementation. Stage 1 participants took 150 ml of low-fat milk twice a day for three weeks as a baseline diet control. Probiotics (Bifidobacterium lactis) were added to milk during stage 2 in a usual dosage (4×1010 organisms /d) or a low dose (4×109 organisms /d) for 3 weeks. During stage 3, for three weeks, they took low-fat milk. Peripheral blood samples were used to examine changes in the ratios of tumor-cell-killing and leukocyte phagocytic activities. Result: The level of NK cells and T lymphocytes were found to be increased in the blood of the individuals. NK cell’s tumoricidal activity was also increased following B. lactis intake, as were the phagocytic capacities of mononuclear and polymorphonuclear phagocytes. Subjects with weak pretreatment immune responses had the highest improvement in immunity. Conclusion: Supplementing the diets of children with B. lactis (a probiotic) may help improve their cellular immunity and physical development.

Targeting PARP11 to avert immunosuppression and improve CAR T therapy in solid tumors.

Evasion of antitumor immunity and resistance to therapies in solid tumors are aided by an immunosuppressive tumor microenvironment (TME). We found that TME factors, such as regulatory T cells and adenosine, downregulated type I interferon receptor IFNAR1 on CD8+ cytotoxic T lymphocytes (CTLs). These events relied upon poly-ADP ribose polymerase-11 (PARP11), which was induced in intratumoral CTLs and acted as a key regulator of the immunosuppressive TME. Ablation of PARP11 prevented loss of IFNAR1, increased CTL tumoricidal activity and inhibited tumor growth in an IFNAR1-dependent manner. Accordingly, genetic or pharmacologic inactivation of PARP11 augmented the therapeutic benefits of chimeric antigen receptor T cells. Chimeric antigen receptor CTLs engineered to inactivate PARP11 demonstrated a superior efficacy against solid tumors. These findings highlight the role of PARP11 in the immunosuppressive TME and provide a proof of principle for targeting this pathway to optimize immune therapies.

CD8 agonism functionally activates memory T cells and enhances antitumor immunity.

Memory CD8+ T cells mature after antigen clearance and ultimately express CD8 protein at levels higher than those detected in effector CD8+ T cells. However, it is not clear whether engagement of CD8 in the absence of antigenic stimulation will result in the functional activation of T cells. Here, we found that CD8 antibody-mediated activation of memory CD8+ T cells triggered T cell receptor (TCR) downstream signaling, enhanced T cell-mediated cytotoxicity and promoted effector cytokine production in a glucose- and glutamine-dependent manner. Furthermore, pretreatment of memory CD8+ T cells with an agonistic anti-CD8 antibody enhanced their tumoricidal activity in vitro and in vivo. From these studies, we conclude that CD8 agonism activates glucose and glutamine metabolism in memory T cells and enhances the efficacy of memory T cell-based cancer immunotherapy.

Effects of Modified Melatonin Release on Human Colostrum Neutrophils to Induce Death in the MCF-7 Cell Line.

Cancer is one of the diseases with the highest mortality rate today, with breast cancer being the second most common type among the Brazilian population. Due to its etiological complexity and inefficiency of treatments, studies have focused on new forms of treatment. Among these forms of treatment, hormonal therapy seems to be an excellent auxiliary mechanism in tumoricidal activity, and melatonin has great potential as a modulator of the immune system. Thus, the present study is aimed at evaluating the effect of the hormone melatonin on the coculture of colostrum polymorphonuclear cells and MCF-7 cancer cells and evaluates the effect of this hormone using a modified transport system. A feasibility analysis was performed by fluorescence microscopy at three cell incubation times, 2 hours, 24 hours, and 72 hours. The measurement of cytokines in the cell supernatant occurred in 24 hours, and the apoptosis assay was performed in 72 hours using flow cytometry. The results showed higher levels of cell viability in groups treated with melatonin and less viability in groups containing a coculture of polymorphonuclear cells and MCF-7 after 72 hours of incubation. Furthermore, the apoptosis and necrosis rates were higher in coculture polymorphonuclear and MCF-7 cells, especially in groups containing microemulsion as a modified release agent. These data suggest that melatonin, especially if associated with a modified release system, has immunomodulatory effects on human colostrum polymorphonuclear cells. These cells can play a crucial role in the resolution of the tumor through their mediation and inflammatory action.

Drug-loaded oleic-acid grafted mesoporous silica nanoparticles conjugated with α-lactalbumin resembling BAMLET-like anticancer agent with improved biocompatibility and therapeutic efficacy.

Despite its prominent therapeutic efficacy, chemotherapy has raised serious concerns due to the severe adverse effects and multidrug resistance evoked, which propels the search for safe and green therapeutic agents. BAMLET (bovine α-lactalbumin made lethal against tumor cell) is a well-known protein-based anticancer agent of selective tumoricidal activity. Here, we prepared oleic acid-modified mesoporous silica nanoparticles (OA-MSNs) conjugated with bovine α-lactalbumin, a lipoprotein complex resembling BAMLET formed on the surface of MSNs (MSN-BAMLET) to load the anticancer drug of docetaxel (DTX). Compared to that of OA-MSNs/DTX, the obtained MSN-BAMLET/DTX with a sustained and pH-responsive drug release behaviors exhibited good biocompatibility and enhanced cytotoxic effect against cancer cells. Moreover, the presence of lipoprotein complex in MSN-BAMLET contributed to the improved dispersion of the composite in solution and the inhibitory effect on the migration of cancer cells. Furthermore, the adsorption profiles of protein corona on the obtained nanoparticles were analyzed. It was found that the marked low amount and abundance of plasma proteins were adsorbed on the α-lactalbumin coated siliceous composite demonstrated its long circulation property. Finally, in vivo study showed that MSN-BAMLET/DTX contributed to the effective cancer ablation and the prolonged survival. Therefore, the constructed MSN-BAMLET of the mesoregular structure and peculiar tumoricidal effect provides a manipulable nanoplatform as drug nanocarrier for therapeutic applications.

A Single-Domain TCR-like Antibody Selective for the Qa-1b/Qdm Peptide Complex Enhances Tumoricidal Activity of NK Cells via Blocking the NKG2A Immune Checkpoint

The NKG2A/HLA-E axis is an immune checkpoint that suppresses immune effector activity in the tumor microenvironment. In mice, the ligand for the NKG2A/CD94 inhibitory receptor is the nonclassical MHC molecule Qa-1b, the HLA-E ortholog, which presents the peptide AMAPRTLLL, referred to as Qdm (for Qa-1 determinant modifier). This dominant peptide is derived from the leader sequences of murine classical MHC class I encoded by the H-2D and -L loci. To broaden our understanding of Qa-1b/Qdm peptide complex biology and its tumor protective role, we identified a TCR-like Ab from a single domain VHH library using yeast surface display. The TCR-like Ab (EXX-1) binds only to the Qa-1b/Qdm peptide complex and not to Qa-1b alone or Qa-1b loaded with control peptides. Conversely, currently available Abs to Qa-1b bind independent of peptide loaded. Flow cytometric results revealed that EXX-1 selectively bound to Qa-1b/Qdm-positive B16F10, RMA, and TC-1 mouse tumor cells but only after pretreatment with IFN-γ; no binding was observed following genetic knockdown of Qa-1b or Qdm peptide. Furthermore, EXX-1 Ab blockade promoted NK cell-mediated tumor cell lysis in vitro. Our findings show that EXX-1 has exquisite binding specificity for the Qa-1b/Qdm peptide complex, making it a valuable research tool for further investigation of the Qa-1b/Qdm peptide complex expression and regulation in healthy and diseased cells and for evaluation as an immune checkpoint blocking Ab in syngeneic mouse tumor models.

Therapeutic Effects of Synthetic Triblock Amphiphilic Short Antimicrobial Peptides on Human Lung Adenocarcinoma.

Because of their unique properties, antimicrobial peptides (AMPs) represent a potential reservoir of novel anticancer therapeutic agents. However, only a few AMPs can kill tumors with high efficiency, and obtaining inexpensive anticancer AMPs with strong activity is still a challenge. In our previous work, a series of original short amphiphilic triblock AMP (KnFmKn) analogues were developed which were demonstrated to exert excellent effects on bacterial infection, both in vitro and in vivo. Herein, the overall objectives were to assess the potent tumoricidal capacities of these analogues against human lung cancer cell line A549 and the underlying mechanism. The results of the CCK-8 assay revealed that the precise modification of the peptides’ primary sequences could modulate their tumoricidal potency. In the tumoricidal progress, positive charge and hydrophobicity were the key driving forces. Among these peptides, K4F6K4 displayed the most remarkable tumoricidal activity. Furthermore, the excellent anticancer capacity of K4F6K4 was proven by the live/dead cell staining, colony formation assay, and tumor growth observations on xenografted mice, which indicated that K4F6K4 might be a promising drug candidate for lung cancer, with no significant adverse effects in vitro or in vivo. In addition, the cell apoptosis assay using flow cytometry, the morphology observations using the optical microscope, confocal microscopy using CellMask™ Deep Red staining, and scanning electron microscope suggested that membrane disruption was the primary mechanism of its antitumor action. Through analyzing the structure–activity relationship, it was found that the amount of positive charge required for KnFmKn to exert its optimal tumoricidal effect was more than that needed for the antimicrobial activity, while the optimal proportion of hydrophobicity was less. Our findings suggest that further analysis of the structure–activity relationship of AMPs’ primary sequence variations will be beneficial. Hopefully, this work can provide guiding principles in designing peptide-based therapeutics for lung cancer.

Synthesis, Characterization, and In Vivo Cytokinome Profile of IL-12-Loaded PLGA Nanospheres.

We report the successful encapsulation and elution of recombinant murine IL-12 (rmIL-12) from poly(lactide-co-glycolic) acid (PLGA) nanospheres (IL-12-NS) synthesized using the double emulsion/solvent evaporation (DESE) technique with microsphere depletion through ultracentrifugation. Images obtained with scanning electron microscopy (SEM) showcased a characteristic spherical shape with a mean particle diameter of 138.1 ± 10.8 nm and zeta potential of −15.1 ± 1.249 mV. These values suggest minimal flocculation when in solution, which was reflected in an in vivo biodistribution study that reported no observed morbidity/mortality. Encapsulation efficiency (EE) was determined to be 0.101 ± 0.009% with average particle concentration obtained per batch of 1.66 × 109 ± 4.45 × 108 particles/mL. Disparate zeta (ζ) potentials obtained from both protein-loaded and protein-unloaded batches suggested surface adsorption of protein, and confocal microscopy of BSA-FITC-loaded nanospheres confirmed the presence of protein within the polymeric shell. Furthermore, elution of rmIL-12 from IL-12-NS at a concentration of 500 million particles/mL was characterized using enzyme-linked immunosorbent assay (ELISA). When IL-12-NS was administered in vivo to female BALB/c mice through retroorbital injection, IL-12-NS produced a favorable systemic cytokine profile for tumoricidal activity within the peripheral blood. Whereas IFN-γ nadir occurred at 72 hours, levels recovered quickly and displayed positive correlations postburst out to 25 days postinjection. IL-12-NS administration induced proinflammatory changes while prompting minimal counterregulatory increases in anti-inflammatory IL-10 and IL-4 cytokine levels. Further, while IL-6 levels increased to 30 folds of the baseline during the burst phase, they normalized by 72 hours and trended negatively throughout the sill phase. Similar trends were observed with IL-1β and CXCL-1, suggesting a decreased likelihood of progression to a systemic inflammatory response syndrome-like state. As IL-12-NS delivers logarithmically lower amounts of IL-12 than previously administered during human clinical trials, our data reflect the importance of IL-12-NS which safely create a systemic immunostimulatory environment.

Tumor-derived Jagged1 promotes cancer progression through immune evasion.

Immune checkpoint inhibitor (ICI) therapy is generating remarkable responses in individuals with cancer, but only a small portion of individuals with breast cancer respond well. Here we report that tumor-derived Jagged1 is a key regulator of the tumor immune microenvironment. Jagged1 promotes tumorigenesis in multiple spontaneous mammary tumor models. Through Jagged1-induced Notch activation, tumor cells increase expression and secretion of multiple cytokines to help recruit macrophages into the tumor microenvironment. Educated macrophages crosstalk with tumor-infiltrating Tcells to inhibit Tcell proliferation and tumoricidal activity. In individuals with triple-negative breast cancer, a high expression level of Jagged1 correlates with increased macrophage infiltration and decreased Tcell activity. Co-administration of an ICI PD-1 antibody with a Notch inhibitor significantly inhibits tumor growth in breast cancer models. Our findings establish a distinct signaling cascade by which Jagged1 promotes adaptive immune evasion of tumor cells and provide several possible therapeutic targets.

Biocompatible thermoresponsive N-isopropyl-N-(3-(isopropylamino)-3-oxopropyl)acrylamide-based random copolymer: synthesis and studies of its composition dependent properties and anticancer drug delivery efficiency.

A new acrylamide monomer, N-isopropyl-N-(3-(isopropylamino)-3-oxopropyl)acrylamide (M3i), consisting of both isopropyl and isopropylamidopropyl moieties, has been synthesized from isopropylamine and N-isopropylacrylamide via an aza-Michael addition reaction followed by amidation with acryloyl chloride. The homopolymer of M3i (polyM3i) and a series of random copolymers of M3i and poly(ethylene glycol)methyl ether acrylate (PEGA: CH2CHCO2(CH2CH2O)nMe, Mn = 480, n = 9 on average) with varying compositions have been synthesized via reversible addition-fragmentation chain transfer polymerization using 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid (DDMAT) as well as 1-phenylethyl phenyl dithioacetate (PEPD) as a RAFT agent. These polymers have been characterized by 1H NMR, FTIR, GPC, UV-Vis, fluorescence, TGDTA, DSC, DLS, and TEM techniques. A lower critical solution temperature (LCST) and glass transition temperature (Tg) for polyM3i prepared using DDMAT were observed at 17 and 133 °C, respectively, while for a polymer formed using PEPD, no LCST was observed until 0 °C and its observed Tg was found at 127.3 °C. The polymers are thermally stable up to 300 °C. Upon an increase in the M3i content in the copolymers, LCST decreases, Tg increases, and the apparent hydrodynamic diameter decreases. Moreover, the effects of concentration and the addition of urea and sodium chloride on the LCST of the copolymer with an LCST close to body temperature were studied. Owing to the incorporation of PEGA, a higher critical micellar concentration and larger TEM particle size of this copolymer were observed with respect to those of polyM3i. The usefulness of the micelles of the copolymers as nano-carriers for the drug doxorubicin was explored. The in vitro tumoricidal activity of the micelles of the doxorubicin-loaded copolymers was also assessed against Dalton's lymphoma cells.

Allogeneic CD20-targeted γδ T cells exhibit innate and adaptive antitumor activities in preclinical B-cell lymphoma models.

ObjectivesAutologous chimeric antigen receptor (CAR) αβ T‐cell therapies have demonstrated remarkable antitumor efficacy in patients with haematological malignancies; however, not all eligible cancer patients receive clinical benefit. Emerging strategies to improve patient access and clinical responses include using premanufactured products from healthy donors and alternative cytotoxic effectors possessing intrinsic tumoricidal activity as sources of CAR cell therapies. γδ T cells, which combine innate and adaptive mechanisms to recognise and kill malignant cells, are an attractive candidate platform for allogeneic CAR T‐cell therapy. Here, we evaluated the manufacturability and functionality of allogeneic peripheral blood‐derived CAR+ Vδ1 γδ T cells expressing a second‐generation CAR targeting the B‐cell‐restricted CD20 antigen.MethodsDonor‐derived Vδ1 γδ T cells from peripheral blood were ex vivo‐activated, expanded and engineered to express a novel anti‐CD20 CAR. In vitro and in vivo assays were used to evaluate CAR‐dependent and CAR‐independent antitumor activities of CD20 CAR+ Vδ1 γδ T cells against B‐cell tumors.ResultsAnti‐CD20 CAR+ Vδ1 γδ T cells exhibited innate and adaptive antitumor activities, such as in vitro tumor cell killing and proinflammatory cytokine production, in addition to in vivo tumor growth inhibition of B‐cell lymphoma xenografts in immunodeficient mice. Furthermore, CD20 CAR+ Vδ1 γδ T cells did not induce xenogeneic graft‐versus‐host disease in immunodeficient mice.ConclusionThese preclinical data support the clinical evaluation of ADI‐001, an allogeneic CD20 CAR+ Vδ1 γδ T cell, and a phase 1 study has been initiated in patients with B‐cell malignancies (NCT04735471).