Selective Killing Activity Research Articles

Abstract LB342: Potent Anti-Tumor Activity Demonstrated by Anti-AXL CAR T Cell Therapy and AXL-ADC in Lung Cancer and Breast Cancer Models

Abstract AXL is over-expressed in various cancers. Its signaling pathway is related to tumor progress. We created a novel a novel AXL-ADC (Hu002-MMAE) based on humanized AXL-targeted antibody (Hu002). We also developed anti-AXL CAR T cells and AXL-CAR iNKT to evaluate anti-tumor effect. Methods: 1) Evaluate the cytotoxicity of Hu002-MMAE in 5 AXL-high-expressing cells. 2) in vivo efficacy validation of Hu002-MMAE into LCLC-103H-bearing Nude mice and U87MG-bearing nude mice. 3) Evaluate the cytotoxicity of anti-AXL CAR-T and AXL CAR-iNKT cells in cell lines with different AXL expression levels to validate the selectivity. 4) in vivo efficacy validation of anti-AXL CAR T cells into MDA-MB-231-bearing mice.Results: Hu002 demonstrates potent binding affinity significantly inhibited the migration of AXL-high tumor cells. The Hu002-MMAE showed potent cytotoxicity against AXL-high tumor cells (IC50 < 0.1 nmol/L) and had a longer-term therapeutic effect in a variety of NSCLC and glioma tumors in vivo (MED < 0.5 mg/kg). Anti-AXL CAR-T cells and AXL CAR-iNKT exhibited strong killing activity to AXL-high-expressed cell lines LCLC-103H and MDA-MB-231 in vitro, while shows minimum effect of anti-tumor effect in AXL-low-expressed cell lines H460 and MDA-MB-453. In in vivo models of MDA-MB-231, we observed increased infiltration of T cells in primary tumor and reduced lung metastasis after AXL CAR-T treamtment.Conclusion: Anti-AXL CAR T and AXL-ADC cells showed strong and selective killing activity, improved TME in primary tumor and mitigate lung metastasis, which makes it a potential strategy for cancers. Citation Format: Zhongen Wu, Yang Gao, Jingpeng Pei, Enfeng Zhao, Shenglin Mei, Yuxiong Feng, Di Zhu. Potent Anti-Tumor Activity Demonstrated by Anti-AXL CAR T Cell Therapy and AXL-ADC in Lung Cancer and Breast Cancer Models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB342.

PH-Responsive Antimicrobial Peptide with Selective Killing Activity for Bacterial Abscess Therapy.

The unusual acidic pH of the abscess milieu is an adverse factor that decreases the therapeutic efficacy of traditional antibiotics. Moreover, avoiding both the undesired killing of commensal bacteria and the development of drug resistance remains difficult during abscess therapy. Hence, we synthesized a series of pH-responsive antimicrobial peptides equipped with efficient bacterial killing activity at pH 6.5 and inactivity at pH 7.4. Among the peptides, F5 exhibited outstanding pH-responsive antimicrobial activity and low toxicity. Fluorescence spectroscopy and electron microscopy illustrated that F5 killed bacteria via a membrane-disruptive mechanism at acidic pH values. Mouse cutaneous abscesses revealed that F5 was equipped with excellent therapeutic ability to reduce the bacterial load and cytokines without causing skin toxicity. In summary, this study reveals a strategy for selectively killing bacteria under the pathologic conditions of abscess sites while avoiding the elimination of commensal bacteria under normal physiological pH levels.

Adenoviral protein E4orf4 interacts with the polarity protein Par3 to induce nuclear rupture and tumor cell death.

The tumor cell-selective killing activity of the adenovirus type 2 early region 4 ORF4 (E4orf4) protein is poorly defined at the molecular level. Here, we show that the tumoricidal effect of E4orf4 is typified by changes in nuclear dynamics that depend on its interaction with the polarity protein Par3 and actomyosin contractility. Mechanistically, E4orf4 induced a high incidence of nuclear bleb formation and repetitive nuclear ruptures, which promoted nuclear efflux of E4orf4 and loss of nuclear integrity. This process was regulated by nucleocytoskeletal connections, Par3 clustering proximal to nuclear lamina folds, and retrograde movement of actin bundles that correlated with nuclear ruptures. Significantly, Par3 also regulated the incidence of spontaneous nuclear ruptures facilitated by the downmodulation of lamins. This work uncovered a novel role for Par3 in controlling the actin-dependent forces acting on the nuclear envelope to remodel nuclear shape, which might be a defining feature of tumor cells that is harnessed by E4orf4.

Rice Seeds as Biofactories of Rationally Designed and Cell-Penetrating Antifungal PAF Peptides.

PAFs are short cationic and tryptophan-rich synthetic peptides with cell-penetrating antifungal activity. They show potent and selective killing activity against major fungal pathogens and low toxicity to other eukaryotic and bacterial cells. These properties make them a promising alternative to fulfill the need of novel antifungals with potential applications in crop protection, food preservation, and medical therapies. However, the difficulties of cost-effective manufacturing of PAFs by chemical synthesis or biotechnological production in microorganisms have hampered their development for practical use. This work explores the feasibility of using rice seeds as an economical and safe production system of PAFs. The rationally designed PAF102 peptide with improved antifungal properties was selected for assessing PAF biotechnological production. Two different strategies are evaluated: (1) the production as a single peptide targeted to protein bodies and (2) the production as an oleosin fusion protein targeted to oil bodies. Both strategies are designed to offer stability to the PAF peptide in the host plant and to facilitate its downstream purification. Our results demonstrate that PAF does not accumulate to detectable levels in rice seeds when produced as a single peptide, whereas it is successfully produced as fusion protein to the Oleosin18, up to 20 μg of peptide per gram of grain. We show that the expression of the chimeric Ole18-PAF102 gene driven by the Ole18 promoter results in the specific accumulation of the fusion protein in the embryo and aleurone layer of the rice seed. Ole18-PAF102 accumulation has no deleterious effects on seed yield, germination capacity, or seedling growth. We also show that the Oleosin18 protein serves as carrier to target the fusion protein to oil bodies facilitating PAF102 recovery. Importantly, the recovered PAF102 is active against the fungal phytopathogen Fusarium proliferatum. Altogether, our results prove that the oleosin fusion technology allows the production of PAF bioactive peptides to assist the exploitation of these antifungal compounds.

Cold Physical Plasma Selectively Elicits Apoptosis in Murine Pancreatic Cancer Cells In Vitro and In Ovo.

Poor prognosis of pancreatic cancer has remained almost unchanged in recent years. Cold physical plasma was suggested as an innovative anticancer strategy, but its selective killing activity of malignant over non-malignant cells has only partially been explored. The present study aimed at exploring the effect of cold physical plasma on cellular viability. Induction of cell death and apoptosis by cold physical plasma was investigated in murine PDA6606 pancreatic cancer cells and primary murine fibroblasts in vitro (2D and 3D cultures) and in ovo. Plasma increased apoptosis in PDA6606 to a significantly higher extent compared to fibroblasts. Antioxidants abrogated these effects, suggesting a prime role of reactive oxygen species in plasma-induced apoptosis. Plasma increased apoptosis of 3D PDA6606 multicellular spheres grown in vitro and in ovo, to significantly higher rates compared to that of fibroblasts, with minimum in ovo inflammation or necrosis observed by hematoxylin and eosin staining (H&E). These data support the future intra-operative application of cold physical plasma for the treatment of microscopic residual tumor tissue after surgical resection.

Linking High-Throughput Screens to Identify MoAs and Novel Inhibitors of Mycobacterium tuberculosis Dihydrofolate Reductase.

Though phenotypic and target-based high-throughput screening approaches have been employed to discover new antibiotics, the identification of promising therapeutic candidates remains challenging. Each approach provides different information, and understanding their results can provide hypotheses for a mechanism of action (MoA) and reveal actionable chemical matter. Here, we describe a framework for identifying efficacy targets of bioactive compounds. High throughput biophysical profiling against a broad range of targets coupled with machine learning was employed to identify chemical features with predicted efficacy targets for a given phenotypic screen. We validate the approach on data from a set of 55 000 compounds in 24 historical internal antibacterial phenotypic screens and 636 bacterial targets screened in high-throughput biophysical binding assays. Models were built to reveal the relationships between phenotype, target, and chemotype, which recapitulated mechanisms for known antibacterials. We also prospectively identified novel inhibitors of dihydrofolate reductase with nanomolar antibacterial efficacy against Mycobacterium tuberculosis. Molecular modeling provided structural insight into target-ligand interactions underlying selective killing activity toward mycobacteria over human cells.

Nanomedicine Assembled by Coordinated Selenium-Platinum Complexes Can Selectively Induce Cytotoxicity in Cancer Cells by Targeting the Glutathione Antioxidant Defense System.

Selenium is a unique, essential trace element that plays an important role in the antioxidant defense and redox regulation of biological processes. We have reported that novel selenium-containing platinum-based anticancer molecules (EG-Se/Pt) had selective cytotoxicity toward cancer cells. Herein, we found the underlying mechanism of selective cytotoxicity to be closely related to the glutathione antioxidant defense system. Elevated reactive oxygen species (ROS) make cancer cells more vulnerable to further elevation of ROS. EG-Se/Pt can induce abnormal increases in ROS by depletion of glutathione. Consequently, the mitochondrial membrane potential collapses and cytochrome c is released, resulting in cell apoptosis. However, EG-Se/Pt analogues, such as EG-Se/Cu and EG-Se/Ni, did not exhibit glutathione depletion capacity or selective killing activity in our investigation, although they can effectively kill cancer cells. These results suggest that the glutathione antioxidant system is an effective target to enable therapeutic selectivity. The amphiphilic property of the selenium-platinum coordination molecules facilitates their assembly into nanoparticles and prolongs the circulation time of the drug in the bloodstream, which is important for in vivo drug delivery. Our in vivo anticancer study demonstrated that the tumor growth inhibition rate of EG-Se/Pt can reach 69% (p < 0.05). What is more encouraging is that EG-Se/Pt exhibited minimal side effects compared to cisplatin. This work also provides new opportunities for the development of therapeutic strategies against cancer.

TheIn VitroandIn VivoAntitumor Activity of Adenovirus-Mediated Interleukin-24 Expression for Laryngocarcinoma

Interleukin-24 (IL-24)/melanoma differentiation associated gene-7 (mda-7) as a novel tumor-suppressor gene has potent antitumor activities in a broad spectrum of human cancers through the activation of various signaling pathways. However, the suppressive effect of adenovirus-mediated IL-24 (Ad-IL-24) expression on human laryngeal cancers is still elusive. In this study, we explored the therapeutic effect of Ad-IL-24 on human laryngeal cancers in vitro and in vivo in an athymic nude mouse model, using a Hep-2 human laryngocarcinoma cell line, and a WI-38 human diploid cell line served as a normal cell control. We demonstrated that Ad-IL-24 induced significant growth inhibition and apoptosis, upregulated the expression of P21, P27, and Bax, downregulated Bcl-2 expression, and activated caspase-3 in Hep-2 laryngeal tumor cells, while it exerted no direct effect on the in vitro proliferation of WI-38 normal diploid cells. Moreover, intratumoral injections of Ad-IL-24 in nude mice bearing Hep-2 tumors significantly suppressed the laryngeal xengrafted tumor growth and reduced microvessel density (MVD) and VEGF expression in tumors. This retarded tumor growth in vitro and in vivo elicited by Ad-IL-24 was closely associated with the upregulation of proliferation-related molecules P21 and P27, decrease in the ratio of anti- to proapoptotic molecules Bcl-2/Bax, followed by the activation of caspase-3, leading to apoptosis via intrinsic apoptotic pathways, and the reduced expression of proangiogenic factor VEGF involved in the inhibition of tumor angiogenesis. Thus, our results indicate that the potent, selective killing activity of Ad-IL-24 in laryngeal cancer cells, but not in normal cells, makes this vector a potential candidate for laryngeal cancer gene therapy.

Stability and Activity in Sputum of G10KHc, a Potent Anti‐Pseudomonas Antimicrobial Peptide

G10KHc, a specifically targeted antimicrobial peptide developed in our laboratory, has shown rapid and selective killing activity against Pseudomonas aeruginosa in culture medium. Because of the major role played by this pathogen in cystic fibrosis, we sought to evaluate the utility of G10KHc under more physiologic conditions in vitro. In the current study, we found that robust G10KHc activity could be maintained in expectorated sputum if serine protease-dependent digestion associated with this fluid was inhibited, either by chemical antagonists or by the construction of a D-amino acid enantiomer of G10KHc. Further investigations revealed that specifically targeted antimicrobial peptide activity in sputum could be further enhanced when samples were treated with a combination of peptide and recombinant human DNase. Our results illustrate the importance of investigating combination therapy to treat cystic fibrosis, especially if protease-sensitive peptide-based agents, such as G10KHc, are to be developed as alternatives to, or in conjunction with, conventional small-molecule antibiotics.

TRAIL is expressed in the brain cells of Alzheimer's disease patients.

Tumour-necrosis-factor-related apoptosis-inducing ligand (TRAIL) is a novel cytokine characterized by selective killing activity against tumour cells. We recently found that beta-amyloid-induced apoptosis in a human neuronal cell line was mediated via induction of TRAIL. Here, we show that TRAIL is specifically expressed in the brain of Alzheimer's disease (AD) patients and completely absent in the brain of non-demented patients. TRAIL-like immunoreactivity was localized in AD affected regions, such as cerebral cortex, often in the proximity of Congo-red-positive amyloid plaques. These findings suggest that neurons represent an independent and potential source of TRAIL, suggesting that the latter acts redundantly with other noxious stimuli in neurodegenerative diseases characterized by amyloidosis and neuroinflammation.

Denileukin diftitox (ONTAK) as targeted therapy against steroid refractory graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (HSCT)

Denileukin diftitox (ONTAK®) is a recombinant fusion protein composed of human interleukin-2 linked to the membrane translocation and catalytic domains of diphtheria toxin. ONTAK has potent selective killing activity against activated lymphocytes that express the high or intermediate affinity interleukin-2 receptor (IL-2R). Monoclonal antibodies that target the IL-2R have demonstrated clinical activity against acute GVHD. ONTAK may be superior to these agents because it does not rely on secondary effector mechanisms for cell kill, and entry of a few molecules into the cytoplasm may be sufficient to induce apoptosis. Furthermore, because ONTAK selectively destroys activated T-cells and spares resting lymphoid populations, valuable immune function and reconstitution potential may be preserved. We have completed a phase I study to assess the dosing of ONTAK in patients with steroid-refractory GVHD after allogeneic HSCT. Thirty patients (3 related donor, 27 unrelated donor) were treated for grade II (n = 10), grade III (n = 15), or grade IV (n = 5) steroid-refractory acute GVHD. Seven received ONTAK at dose level I (9 μg/kg IV on day 1 and 15), eighteen were treated on dose level II (9 μg/kg IV days 1,3,5,15,17,19), five were treated on dose level III (9 μg/kg IV days 1–5, 15–19). At dose level III, 4 of 5 subjects developed dose-limiting toxicity (1 acute renal failure, 3 hepatic transaminase elevation). Therefore, dose level II was deemed the maximum tolerated dose (MTD). In all patients, elevated transaminases resolved promptly upon withdrawal of ONTAK. Only 2 (7%) developed infusional reactions with transient hypotension. Twenty-four patients were evaluable for GVHD response. After 4 weeks, 8 (33%) had complete GVHD resolution (CR) of, 9(38%) had partial response (PR), for an overall response rate of 71%. Among the 9 PRs, 4 subsequently entered CR without additional GVHD therapy, resulting in an overall CR of 50%. Response was highest at the MTD, where 6 (46%) achieved CR, and 3 (23%) had PR, all of whom eventually converted to CR (overall CR = 69%). Of the 24 patients evaluable for GVHD response, 9(38%) are alive, with the longest survivor being GVHD free at 20 months. Our results show that ONTAK at a dose schedule of 9 μg/kg IV on days 1,3,5,15,17,19 is tolerable and has promising activity for steroid-refractory GVHD. Future studies using the MTD are warranted to investigate the potential role of ONTAK as primary treatment of acute GVHD.

Kigamicins, novel antitumor antibiotics. I. Taxonomy, isolation, physico-chemical properties and biological activities.

Novel antibiotics named kigamicin A, B, C, D, and E were discovered from the culture broth of Amycolatopsis sp. ML630-mF1 by their selective killing activity against PANC-1 cells only under a nutrient starved condition. Under a condition of nutrient starvation, kigamicins A, B, C, and D inhibited PANC-1 cell survival at 100 times lower concentration than in normal culture. Kigamicins showed antimicrobial activity against Gram-positive bacteria including methicillin resistant Staphylococcus aureus (MRSA). Kigamicin D inhibited the growth of various mouse tumor cell lines at IC50 of about 1 microg/ml.

Melanoma Differentiation Associated Gene-7 (mda-7): A Novel Anti-Tumor Gene for Cancer Gene Therapy

The mda-7 gene (melanoma differentiation associated gene-7) is a novel tumor suppressor gene. The anti-proliferative activity of MDA-7 has been previously reported. In this report, we analyze the anti-tumor efficacy of Ad-mda7 in a broad spectrum of cancer lines. Ad-mda7-transduced cancer or normal cell lines were assayed for cell proliferation (tritiated thymidine incorporation assay, Alamar blue assay, and trypan-blue exclusion assay), apoptosis (TUNEL, and Annexin V staining visualized by fluorescent microscopy or FACs analysis), and cell cycle regulation (Propidium Iodide staining and FACs analysis). Ad-mda7 treatment of tumor cells resulted in growth inhibition and apoptosis in a temporal and dose-dependent manner. The anti-tumor effects were independent of the genomic status of p53, RB, p16, ras, bax, and caspase 3 in these cells. In addition, normal cell lines did not show inhibition of proliferation or apoptotic response to Ad-mda7. Moreover, Ad-mda7-transduced cancer cells secreted a soluble form of MDA-7 protein. Thus, Ad-mda7 may represent a novel gene-therapeutic agent for the treatment of a variety of cancers. The potent and selective killing activity of Ad-mda7 in cancer cells but not in normal cells makes this vector a potential candidate for cancer gene therapy.

Selective Killing of HIV-Infected Cells by Liposomes Composed of dimyristoylphosphatidylcholine/phosphatidylserine/cholesterol

We have previously shown that liposomes containing fragment A of diphtheria toxin, which were prepared by the detergent-dialysis method with egg phosphatidylcholine, phosphatidylserine and cholesterol, possess a selective killing activity against human immunodeficiency virus (HIV)-1-infected cells, but not against uninfected cells (Ikuta et al., 1987). Since the liposomes were found to be unstable in human plasma in vitro, we prepared improved liposomes by the extrusion method with dimyristoylphosphatidylcholine instead of egg phosphatidylcholine. These liposomes were found to be very stable in human plasma, and also possessed the selective killing activity against HIV-1-infected cells. In addition, it was found that the fragment A in the liposomes was not necessary for the selective cell killing activity. The cell killing activity and selectivity of HIV-1-infected cells of the liposomes were remarkably affected by cholesterol content and the acyl chain length of the saturated fatty acid of phosphatidylcholines. These data suggest that membranes of liposomes can interact specifically with HIV-1-infected cells, but not with uninfected cells, resulting in the inhibition of cell proliferation.