Novel anti-CD30/CD3 bispecific antibodies activate human T cells and mediate potent anti-tumor activity

CD30 is expressed on Hodgkin lymphomas (HL), many non-Hodgkin lymphomas (NHLs), and non-lymphoid malignancies in children and adults. Tumor expression, combined with restricted expression in healthy tissues, identifies CD30 as a promising immunotherapy target. An anti-CD30 antibody-drug conjugate (ADC) has been approved by the FDA for HL. While anti-CD30 ADCs and chimeric antigen receptors (CARs) have shown promise, their shortcomings and toxicities suggest that alternative treatments are needed. We developed novel anti-CD30 x anti-CD3 bispecific antibodies (biAbs) to coat activated patient T cells (ATCs) ex vivo prior to autologous re-infusions. Our goal is to harness the dual specificity of the biAb, the power of cellular therapy, and the safety of non-genetically modified autologous T cell infusions. We present a comprehensive characterization of the CD30 binding and tumor cell killing properties of these biAbs. Five unique murine monoclonal antibodies (mAbs) were generated against the extracellular domain of human CD30. Resultant anti-CD30 mAbs were purified and screened for binding specificity, affinity, and epitope recognition. Two lead mAb candidates with unique sequences and CD30 binding clusters that differ from the ADC in clinical use were identified. These mAbs were chemically conjugated with OKT3 (an anti-CD3 mAb). ATCs were armed and evaluated in vitro for binding, cytokine production, and cytotoxicity against tumor lines and then in vivo for tumor cell killing. Our lead mAb was subcloned to make a Master Cell Bank (MCB) and screened for binding against a library of human cell surface proteins. Only huCD30 was bound. These studies support a clinical trial in development employing ex vivo-loading of autologous T cells with this novel biAb.

Bispecific antibody-targeted T-cell therapy for acute myeloid leukemia

The management of relapsed or refractory acute myeloid leukemia (AML) continues to be therapeutically challenging. Non-toxic immunotherapy approaches are needed to provide long-term anti-leukemic effects. The goal of this study was to determine whether activated T cells (ATCs) armed with bispecific antibodies (BiAbs) could target and lyse leukemic and leukemic stem cells (LSCs). Anti-CD3 × anti-CD123 BiAb (CD123Bi) and anti-CD3 × anti-CD33GO (gemtuzumab ozogamicin [GO]) BiAb (CD33GOBi) were used to arm ATCs to produce bispecific antibody armed activated T cells (designated CD123 BATs or CD33GO BATs) to target AML cell lines, peripheral blood mononuclear cells from AML patients, and in vivo treatment of AML in xenogeneic NSG mice engrafted with leukemic cells. BATs exhibited high levels of specific cytotoxicity directed at AML cell lines at low 1:1 or 1:2 effector-to-target (E:T) ratios and secrete Th₁ cytokines upon target engagement. In vivo study in AML-engrafted NSG mice showed significantly prolonged survival in mice treated with CD33GO BATs (p < 0.0001) or CD123 BATs (p < 0.0089) compared to ATC-treated control mice. Patient samples containing leukemic blasts and LSCs when treated with CD33GO BATs or CD123 BATs for 18 h showed a significant reduction (50%-100%; p < 0.005) in blasts and 75%-100% reduction in LSCs (p < 0.005) in most cases compared to unarmed ATCs. This approach may provide a potent and non-toxic strategy to target AML blasts and LSCs and enhance chemo-responsiveness in older patients who are likely to develop recurrent diseases.

Bispecific Antibody Armed Metabolically Enhanced Headless CAR T Cells

Adoptive T cell therapies for solid tumors is challenging. We generated metabolically enhanced co-activated-T cells by transducing intracellular co-stimulatory (41BB, ICOS or ICOS-27) and CD3ζ T cell receptor signaling domains followed by arming with bispecific antibodies (BiAbs) to produce armed “Headless CAR T cells” (hCART). Various hCART armed with BiAb directed at CD3ϵ and various tumor associated antigens were tested for: 1) specific cytotoxicity against solid tumors targets; 2) repeated and dual sequential cytotoxicity; 3) survival and cytotoxicity under in vitro hypoxic condition; and 4) cytokine secretion. The 41BBζ transduced hCART (hCART_41BBζ) armed with HER2 BiAb (HER2 hCART_41BBζ) or armed with EGFR BiAb (EGFR hCART_41BBζ) killed multiple tumor lines significantly better than control T cells and secreted Th₁ cytokines/chemokines upon tumor engagement at effector to target ratio (E:T) of 2:1 or 1:1. HER2 hCART serially killed tumor targets up to 14 days. Sequential targeting of EGFR or HER2 positive tumors with HER2 hCART_41BBζ followed by EGFR hCART_41BBζ showed significantly increased cytotoxicity compared single antigen targeting and continue to kill under in vitro hypoxic conditions. In summary, metabolically enhanced headless CAR T cells are effective serial killers of tumor targets, secrete cytokines and chemokines, and continue to kill under in vitro hypoxic condition.

Clinical and immune responses using anti-CD3 x anti-EGFR bispecific antibody armed T cells (BATs) for locally advanced or metastatic pancreatic cancer

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Background: Conventional chemotherapy (chemo) for locally advanced pancreatic cancer (LAPC) and metastatic pancreatic cancer (MPC) has dismal responses and poor survival rates. Arming activated T cells (ATC) with anti-CD3 x anti-EGFR bispecific antibody (BATs) makes every ATC into an EGFR-specific cytotoxic T cell that secretes cytokines, proliferates, and kills tumor. Methods: We report on 5 phase I (P1) and 15 phase II (P2) patients. In our phase I study, BATs were used to treat LAPC or MPC patients at Karmanos Cancer Institute (NCT0140874) in a dose escalation involving 3 weekly infusions of 1, 2, and 4 x 1010 BATs/infusion, followed by a booster infusion at 3 months (mos) for a total of up to 8 x 1010 BATs. No dose limiting toxicities were observed in the outpatient infusions. Fifteen patients treated on a phase II (NCT02620865) at KCI and (NCT03269526) at University of Virginia received biweekly infusions of 1010 BATs/infusion over 4 weeks for a total of 8 x 1010 EGFR BATs. Results: Four patients had stable disease (SD) for 6.1, 6.5, 5.3, and 36 mos. Two patients had complete responses (CR) when chemo was restarted after BATs. The median overall survival (OS) for 17 evaluable patients (3 of 4 infusions in the P1 and all 8 infusions in the P2) was 31 mos, and the median OS for all 20 patients (3 in the P2 who did not complete 8 infusions) is 14.5 mos (95% CI, 7.5-45.2 mos). Patient IT20104 had an apparent “pseudoprogression” after 3 BATs infusions, but achieved a CR after restarting capcitabine and is alive off therapy at 54 mos (24 mos after stopping capecitabine). Immune evaluations on the P1 patients show specific cytotoxicity to MiaPaCa-2 by peripheral blood mononuclear cells (PBMC) increased from 21% to 31% 2 weeks after the 3rd infusion, and IFN-γ EliSpots increased from < 20 to 1000 IFN-γ EliSpots/106 PBMC (p < 0.03). Patient IT 20121 (SD for 36 mos) increased IFN-γ EliSpots from 250 to 3200/106 PBMC after 8 infusions. Innate cytotoxicity responses in the P1 patients increased significantly after infusions (p < 0.04). Levels of IP-10 increased significantly (p < 0.04), and levels of IL-8 decreased but not significantly (p < 0.07). Conclusions: Infusions of BATs are safe and induce endogenous adaptive anti-tumor responses. Targeting PC with BATs may stabilize disease, leading to improved OS, as well as evidence that BATs infusions can induce anti-tumor activity and immunosensitize tumors to subsequent chemo. Clinical trial information: NCT014084,NCT03269526,NCT02620865.

Lysolecithin as feed additive enhances collagen expression and villus length in the jejunum of broiler chickens

Adding lysolecithin to feed has reportedly improved the performance of broiler chickens. Lysolecithin is generated by phospholipase catalyzed hydrolysis of lecithin. The enzymatic reaction converts various phospholipids into the corresponding lysophospholipids, with lysophosphatidylcholine (LPC) one of the primary products. Here we compared supplementation with a commercial lysolecithin (Lysoforte®) with comparable levels of highly purified LPC for effects on broilers. Despite no differences in weight gain during the starter period, we discovered a significant increase in average villus length with lysolecithin and an increase in villus width with purified LPC. High-throughput gene expression microarray analyses revealed many more genes were regulated in the epithelium of the jejunum by lysolecithin compared to purified LPC. The most up-regulated genes and pathways were for collagen, extracellular matrix, and integrins. Staining sections of the jejunum with Picrosirius Red confirmed the increased deposition of collagen fibrils in the villi of broilers fed lysolecithin, but not purified LPC. Thus, lysolecithin elicits gene expression in the intestinal epithelium, leading to enhanced collagen deposition and villus length. Purified LPC alone as a supplement does not mimic these responses. Feed supplementation with lysolecithin triggers changes in the intestinal epithelium with the potential to improve overall gut health and performance.

The Use of the Woodchuck as an Animal Model for Evaluation of Transarterial Embolization

There are many shortcomings of current animal models as surrogates of hepatocellular carcinoma that handicap preclinical testing of embolization agents. The present study explores the feasibility of using the woodchuck (Marmota monax) as an animal model for the testing of novel embolization agents. Four woodchucks underwent magnetic resonance imaging, angiography, and left lobar hepatic artery particle embolization. Percutaneous access, arteriography, and lobar embolization were successful in all animals, with angiographic stasis obtained in the target vessel with minimal reflux of embolic material. These results support the feasibility of the woodchuck as an animal model for preclinical testing of embolization agents.

Cinnamic Acid Derivatives Enhance the Efficacy of Transarterial Embolization in a Rat Model of Hepatocellular Carcinoma

INTRODUCTION

We hypothesize that the combination of transarterial embolization (TAE) plus inhibition of lactate export will limit anaerobic metabolism and reduce tumor survival compared to TAE alone. The purpose of this study was to test this hypothesis in a rat model of hepatocellular carcinoma (HCC).

METHODS

Rat N1-S1 hepatoma cells were assayed in vitro using the Seahorse XF analyzer to measure extracellular acidification (lactate excretion) comparing effects of the addition of caffeic acid (CA) or ferulic acid (FA) or UK-5099 with control. Monocarboxylate transporter Slc16a3 was knocked down by RNAi. N1S1 tumors were orthotopically implanted in rats and 4 groups evaluated: (1) Control, (2) TAE-only, (3) TAE plus CA, and (4) TAE plus FA. Tumor size was determined by ultrasound and analyzed by repeated measures statistics. Tumors harvested at 4 weeks were examined by microscopy.

RESULTS

Seahorse assays showed that CA and FA caused a significant reduction by >90% in lactate efflux by N1S1 tumor cells (p < 0.01). Knockdown of Slc16a3 prevented inhibition by CA. In vivo tumors grew 30-fold in volume over 4 weeks in untreated controls. By comparison, TAE resulted in near cessation of growth (10% in 4-week time period). However, both TAE + CA and TAE + FA caused a significant reduction of tumor volumes (87 and 72%, respectively) compared to control and TAE (p < 0.05). Pathologic evaluation revealed residual tumor in the TAE group but no residual viable tumor cells in the TAE + CA and TAE + FA groups.

CONCLUSION

Addition of CA or FA enhances the effectiveness of TAE therapy for HCC in part by blocking lactate efflux.

Poly(A) RNAs including coding proteins RNAs occur in plant Cajal bodies

The localisation of poly(A) RNA in plant cells containing either reticular (Allium cepa) or chromocentric (Lupinus luteus, Arabidopsis thaliana) nuclei was studied through in situ hybridisation. In both types of nuclei, the amount of poly(A) RNA was much greater in the nucleus than in the cytoplasm. In the nuclei, poly(A) RNA was present in structures resembling nuclear bodies. The molecular composition as well as the characteristic ultrastructure of the bodies containing poly(A) RNA demonstrated that they were Cajal bodies. We showed that some poly(A) RNAs in Cajal bodies code for proteins. However, examination of the localisation of active RNA polymerase II and in situ run-on transcription assays both demonstrated that CBs are not sites of transcription and that BrU-containing RNA accumulates in these structures long after synthesis. In addition, it was demonstrated that accumulation of poly(A) RNA occurs in the nuclei and CBs of hypoxia-treated cells. Our findings indicated that CBs may be involved in the later stages of poly(A) RNA metabolism, playing a role storage or retention.

Changes of specific activity of lipase and lipoxygenase during germination of wheat and barley

Changes of lipase and lipoxygenase specific activities were monitored during wheat and barley germination. Statistically significant correlation (r2 = 0.8148, P < or = 0.02) was found between the specific activities of lipase and lipoxygenase during wheat germination, whereas such correlation did not occur during barley germination.

The agreement metric for labeled binary trees

Let S be a set of n objects. A binary tree of S is a binary tree whose leaves are labeled without repetition from S. The operation of pruning a tree T is that of removing some leaves from T and suppressing all inner vertices of degree 2 which are formed by this deletion. Given two trees T and U, an agreement tree is a tree that can be obtained from T as well as from U by pruning the fewest number of leaves from the two trees. A quadratic algorithm is presented for doing this and two metrics are defined based on agreement trees.