Optimizing NK-92 Serial Killers: Gamma Irradiation, CD95/FasLigation, And NK Or LAK Attack Limit Cytotoxic Efficacy

Background: The NK cell line NK-92 and its genetically modified variants are receiving attention as immunotherapies to treat a range of malignancies. However, since NK-92 cells are themselves tumors, they require irradiation prior to transfer and are potentially susceptible to attack by patients’ immune systems. Here, we investigated NK-92 cell-mediated serial killing for the effects of gamma-irradiation and ligation of the death receptor Fas (CD95), and NK-92 cell susceptibility to attack by activated primary blood NK cells. Methods: To evaluate serial killing, we used 51 Cr-release assays with low NK-92 effector cell to target Raji, Daudi or K562 tumor cell (E:T) ratios to determine killing frequencies at 2-, 4-, 6-, and 8-hours. Results: NK-92 cells were able to kill up to 14 Raji cells per NK-92 cell in eight hours. NK-92 cells retained high cytotoxic activity immediately after irradiation with 10 Gy but the cells surviving irradiation lost >50% activity one day after irradiation. Despite high expression of CD95, NK-92 cells maintained their viability following overnight Fas/CD95-ligation but lost some cytotoxic activity. However, one day after irradiation, NK-92 cells were more susceptible to Fas ligation, resulting in decreased cytotoxic activity of the cells surviving irradiation. Irradiated NK-92 cells were also susceptible to killing by both unstimulated and IL-2 activated primary NK cells (LAK). In contrast, non-irradiated NK-92 cells were more resistant to attack by NK and LAK cells. Conclusions: Irradiation is deleterious to both the survival and cytotoxicity mediated by NK-92 cells and renders the NK-92 cells susceptible to Fas-initiated death and death initiated by primary blood NK cells. Therefore, replacement of irradiation as an antiproliferative pretreatment and genetic deletion of Fas and/or NK activation ligands from adoptively transferred cell lines are indicated as new approaches to increase therapeutic efficacy.

In Vitro Anti-Epstein Barr Virus Activity of Olea europaea L. Leaf Extracts

Olea europaea L. var. sativa (OESA) preparations are widely used in traditional medicine in the Mediterranean region to prevent and treat different diseases. In this research, olive extracts derived from the leaves of the OESA tree have been screened for antioxidant activity by two methods: the DPPH free radical scavenging assay (DPPH) and the Ferric reducing antioxidant power (FRAP) assay. The DPPH assay showed that OESA possesses a stronger antioxidant activity (84%) at 1 mg/mL while the FRAP method showed a strong metal ion chelating activity (90%) at 1 mg/mL. The low IC50 values, obtained by two different methods, implies that OESA has a noticeable effect on scavenging free radicals comparable to standards. During EBV infection, the free radicals increased triggering lipid oxidation. Therefore, the monitoring of the secondary lipid peroxidation products was done by measuring malonaldehyde (MDA) and conjugated dienes (DC). The simultaneous treatment of Raji cells with OESA and TPA, as an inductorof the lytic cycle, generated a significant decrease in MDA levels and DC (p < 0.05). Besides, Raji cells simultaneously exposed to TPA and OESA exhibited a percentage of EBV-positive fluorescence cells lower than TPA treated cells (**** p < 0.0001). This suggests that OESA treatment has a protective effect against EBV lytic cycle induction.

266 AK117, a CD47 blocking antibody with robust macrophage activation without red blood cell hemagglutination

BackgroundAK117 is a humanized monoclonal antibody targeting CD47 which widely expresses on innate immune cells, such as macrophages, and functions as a regulator of phagocytosis. CD47 serves as the ligand for a receptor on these innate immune cells, SIRPα, which in turn delivers an inhibitory signal for phagocytosis. Hematology toxicity is the major concern of an anti-CD47 antibody. As an agent targeting CD47 being investigated as an anti-tumor therapeutic, AK117 is engineered on a human IgG4 scaffold to minimize recruitment of Fc-dependent effector functions, as well as identified with favorable hematology safety profile and robust pro-phagocytosis activity.MethodsActivity of AK117 binding to CD47 to block the interaction between CD47 and SIRPα were determined by FACS, and binding of AK117 to human RBC was also evaluated. Raji cells, HT-29 cells, and HL-60 cells which highly express CD47 were used as target cells to evaluate a pro-phagocytic activity of AK117 as a monotherapy or in combination with anti-EGFR antibody, anti-CD20 antibody or azacitidine. In in-vivo pharmacology studies, anti-tumor activity of AK117 was investigated in SCID/beige mouse Raji tumor model. Effects of AK117 on hemagglutination of human RBC at was tested. Hemoglobin (HGB) and hematocrit (HCT) was evaluated after single dose of 10 mg/kg AK117 or Hu-5F9 in male and female cynomolgus monkeys (n=1/gender).ResultsAK117 could effectively binds to CD47, and competes with SIRPα for binding to the antigen on Raji cells (figure 1). AK117 alone or combines with anti-EGFR antibody, anti-CD20 antibody and azacitidine shows potent phagocytosis of tumor cells in a dose-dependent manner (figure 2). AK117 significantly inhibited tumor growth in these tumor models (figure 3). Favorable hematology safety profile of AK117 was observed. A significant weaker binding to human RBC of AK117 was identified (figure 4), and AK117 does not induce hemagglutination of human RBC up to a concentration of 1050 μg/mL, while Hu-5F9 triggers hemagglutination even at a low concentration of 1.44 μg/mL (figure 5). AK117 has minimal anemia effect in monkey studies compared to hu5F9-G4 after single dose in cynomolgus monkeys (figure 6). AK117 showed a rather superior safety profile to Hu5F9-G4 as a shorter duration of anemia.Abstract 266 Figure 1Binding and Competition activity of AK117 to CD47. (A) FACS binding curves of AK117 and Hu5F9-G4 to CD47 on raji cells. (B) FACS competitive binding curve of AK117 and Hu5F9-G4 with SIRPαECD-mFc to CD47 on raji cells.Abstract 266 Figure 2The pro-phagocytic activity against tumor cells. (A) The phagocytic index of raji cells by macrophages with AK117. (B) The phagocytic index of HL-60 cells by macrophages with AK117 and azacitidine. (C) The phagocytic index of HT-29 cells by macrophages with AK117 and cetuximab. (D) The phagocytic index of raji cells by macrophages with AK117 and rituximab.Abstract 266 Figure 3Anti-tumor activity in raji tumor mouse model. The (A) Tumor growth curves and (B) Body weight curves of different groups in SCID/Beige mice with subcutaneous raji tumor.Abstract 266 Figure 4Binding activity of AK117 to human RBCs. Binding Curves of Hu5F9-G4 and AK117 to CD47 on human RBCsAbstract 266 Figure 5Hemagglutination effect on human erythrocytes. Hemagglutination effect of AK117 on human erythrocytesAbstract 266 Figure 6HGB and HCT in cynomolgus monkeys. The curves of (A) hemoglobin and (B) Hematocrit at different times in cynomolgus monkeys.ConclusionsWith pre-clinical pharmacology activities comparable to Hu5F9-G4 as well as superior safety properties demonstrated in non-clinical pharmacodynamics studies, AK117 has emerged as a promising new treatment for solid tumor.

A Metabolomics Investigation of the Metabolic Changes of Raji B Lymphoma Cells Undergoing Apoptosis Induced by Zinc Ions

Zinc plays a pivotal role in the function of cells and can induce apoptosis in various cancer cells, including Raji B lymphoma. However, the metabolic mechanism of Zn-induced apoptosis in Raji cells has not been explored. In this study, we performed global metabolic profiling using UPLC−Orbitrap−MS to assess the apoptosis of Raji cells induced by Zn ions released from ZnO nanorods. Multivariate analysis and database searches identified altered metabolites. Furthermore, the differences in the phosphorylation of 1380 proteins were also evaluated by Full Moon kinase array to discover the protein associated Zn−induced apoptosis. From the results, a prominent increase in glycerophosphocholine and fatty acids was observed after Zn ion treatment, but only arachidonic acid was shown to induce apoptosis. The kinase array revealed that the phosphorylation of p53, GTPase activation protein, CaMK2a, PPAR−γ, and PLA−2 was changed. From the pathway analysis, metabolic changes showed earlier onset than protein signaling, which were related to choline metabolism. LC−MS analysis was used to quantify the intracellular choline concentration, which decreased after Zn treatment, which may be related to the choline consumption required to produce choline-containing metabolites. Overall, we found that choline metabolism plays an important role in Zn-induced Raji cell apoptosis.

Curcumin in Combination With Omacetaxine Suppress Lymphoma Cell Growth, Migration, Invasion, and Angiogenesis via Inhibition of VEGF/Akt Signaling Pathway

BackgroundBoth omacetaxine (HHT) and curcumin were shown to exhibit anti-proliferative effect on lymphoma cells. However, the role of combination of HHT with curcumin (HHT/curcumin combination) on lymphoma cells remains unclear. Thus, this study aimed to investigate the effect of HHT/curcumin combination on the proliferation, migration, and angiogenesis of lymphoma cells.MethodsCell counting kit-8 (CCK-8), Ki67 immunofluorescence and transwell assays were used to assess the viability, proliferation and migration of U937 and Raji cells respectively. In addition, tube formation assay was used to determine the effects of HHT/curcumin combination on angiogenesis in human umbilical vein endothelial cells (HUVECs).ResultsIn this study, we found that HHT/curcumin combination significantly inhibited the proliferation, migration and invasion in U937 and Raji cells (all P &lt; 0.01). In addition, combination treatment markedly inhibited the secreted levels of vascular endothelial growth factor (VEGF)-(A-D) (all P &lt; 0.01) in Raji cells. Moreover, combination treatment exhibited anti-tumor effects in Raji cells, as shown by the decreased signals of phosphorylated VEGF receptor 2 (p-VEGFR2) and phosphorylated protein kinase B (p-Akt) (all P &lt; 0.01). Meanwhile, combination treatment inhibited VEGFA levels (P &lt; 0.01) in exosomes derived from Raji cells. Application of exosomes with downregulated VEGF to HUVECs notably inhibited proliferation, migration and tube formation of HUVECs, evidenced by the decreased signals of p-Akt, angiogenin-1, matrix metallopeptidase 2 (MMP2) and matrix metallopeptidase 9 (MMP9) (all P &lt; 0.01).ConclusionOur findings indicated that combination of HHT and curcumin could inhibit lymphoma cell growth and angiogenesis via inhibition of VEGF/Akt signaling pathway. These results suggested that HHT combined with curcumin might be regarded as a promising therapeutic approach for the treatment of lymphoma.

Modulation of Temoporfin Distribution in Blood by β-Cyclodextrin Nanoshuttles

Photodynamic therapy represents a more targeted and less invasive alternative cancer treatment to traditional modalities. Temoporfin, as with many photosensitizers, is given by injection into a vein, and its subsequent fate is largely determined by the binding to plasma proteins and interaction with endothelial and blood cells. Thus, it is essential to be able to control and to alter the biodistribution of temoporfin in blood. In the present study, we evaluated the effect of co-administration of temoporfin with randomly methylated β-CD (Me-β-CD) on the distribution of temoporfin in the main subpopulations of blood cells of healthy donors using absorbance spectrophotometry and flow cytometry. We showed that cell-bound temoporfin fraction in blood strongly depends on the concentration of Me-β-CD. In fact, the accumulation of temoporfin in white blood cells was more sensitive than that in red blood cells, due to the higher volume of membranous organelles in white blood cells. Finally, we demonstrated that Me-β-CD significantly increases cellular uptake of temoporfin cancer human Burkitt′s lymphoma Raji cells. The presence of Me-β-CD resulted in a spotted pattern of temoporfin distribution in the plasma membrane compartment. Our results clearly demonstrated that β-CDs derivatives provide new options to modulate temoporfin biodistribution in blood.

Isolation, Identification and Genetic Characteristics of an Uncommon Norovirus Genotype, GIX.1[GII.P15], From Kunming, China

Human norovirus, an RNA virus of the family Caliciviridae, is a common viral pathogen causing acute gastroenteritis of all age groups worldwide. To date, tens of thousands genome sequences of norovirus have been uploaded to NCBI database, more than half of them were epidemic strains of GII.4 or GII.17 genotype. However, sequence information on the non-epidemic norovirus strains remains poorly studied. In this study, an uncommon norovirus genotype, GIX.1[GII.P15], was isolated using Raji cells and the full-genome sequence of the strain was extensively characterized. The norovirus virus particles with a diameter of approximately 30 nm and a morphology of spherical and lace-like appearance were observed by electron microscopy. Viral genome replication in Raji cells were confirmed by real-time quantitative reverse transcription-PCR from viral replication kinetics and passaging experiments of the primary virus. Phylogenetic analysis showed that the strain (KMN1) belonged to the GIX.1[GII.P15] genotype and indicated that no recombination has occurred in this strain thus far. Further compared analysis of the full genome sequence with the consensus sequence of GIX.1[GII.P15] genomes revealed a total of 81 nucleotide substitutions (53 in ORF1, 20 in ORF2, and 8 in ORF3) across the genome, but only 6 substitutions resulted in amino acid changes (3 in ORF1, 1 in ORF2, and 2 in ORF3). Moreover, one amino acid substitution at the 302 amino acid site (P302S) was observed in the P2 domain of the capsid protein, and the site was around one of the predicted conformational epitopes on the VP1 protein structure. The genomic information obtained from the novel strain may extend the understanding of the non-epidemic GIX.1[GII.P15] strains.

Temporal gene expression profiling of maslinic acid-treated Raji cells

An hourly progression of gene expression profiling in maslinic acid treated Raji cells, which reported activation of several key pathways.

S-Phase Kinase-Associated Protein-2 and Nuclear Factor-kappa Beta as Molecular Targets of Oral Burkitt’s Lymphoma Cell Induced by Quinolinone Derivate-Vesnarinone

Background: 3,4-Dihydro-6-[4-3,4-dimethoxybenzoyl-1-piperazinyl]-2(1H)-quinolinone (vesnarinone), a novel inotropic drug with unique and complex mechanisms of action, is known to show antitumor activity against several human malignancies. In the present study, vesnarinone-induced signal transduction of S-phase kinase-associated protein 2 (Skp2) and Nuclear Factor-kappa Beta (NF-κB) as molecular targets of oral malignant Burkitt’s lymphoma (Raji cells) was evaluated. Materials and Methods: Raji cells were incubated with vesnarinone at concentrations of 0, 1.25x10-2, 2.50x10-2, or 5.0x10-2 Molar. After 24 h, chemotactic cell migration was examined by a Boyden chamber kit. Apoptosis induction was observed by caspase-9 colorimetric assay. To evaluate levels of Skp2, NF-kB, and α-tubulin, Western blot analysis was performed. Results: Vesnarinone markedly suppressed chemotactic cell migration and significantly induced apoptosis by increasing the caspase-9 activity of Raji cells through down regulation of Skp2 and NF-κB. Conclusion: Vesnarinone decreased the expression of Skp2 and NF-κB indicating these molecules may be targeted for the treatment of oral malignant Burkitt’s lymphoma (BL). The results of this work offer a promising therapeutic approach for BL tumors.