892 ABL503 (TJ-L14B), PD-L1x4–1BB bispecific antibody induces superior anti-tumor activity by PD-L1-dependent 4–1BB activation with the increase of 4–1BB+CD8+ T cells in tumor microenvironment

BackgroundPD-(L)1 inhibitor has revolutionized cancer treatment, but there are unmet clinical needs for PD-(L)1 inhibitor-resistant/refractory patients. Activation of T cells in tumor microenvironment by 4-1BB agonist antibodies is one of the promising approaches to complement the current limitation of PD-(L)1 inhibitors. Although 4-1BB is a promising target for immunotherapy, clinical studies using 4-1BB agonist antibodies showed systemic immune cell activation resulting in dose-limiting hepatotoxicity. We generated ABL503 (TJ-L14B), a bispecific antibody that combines PD-(L)1 blockade and PD-L1-dependent 4-1BB agonistic activity by binding both PD-L1 and 4-1BB to limit unwanted toxicities while exerting a potent anti-tumor efficacy. Here, we reported the pre-clinical properties of ABL503 (TJ-L14B) in various studies.MethodsThe activity of ABL503 (TJ-L14B) was characterized and evaluated in 1) PD-1 and 4-1BB signaling reporter cells cocultured with various tumor cells and PBMCs, 2) hPD-L1/h4-1BB knock-in mice implanted with MC38 tumor expressing different level of hPD-L1, 3) patient-derived lung cancer organoids cocultured with autologous PBMCs, and 4) PBMCs from healthy donors to measure cytokine release.ResultsFunctional evaluation of ABL503 (TJ-L14B) indicates the activation of 4-1BB signaling was solely dependent on engagement of hPD-L1 expressed on immune cells as well as on tumor cells, pointing to pivotal roles of PD-L1 on both immune cells and tumor cells for the activity of ABL503 (TJ-L14B). In vivo anti-tumor activity of ABL503 (TJ-L14B) across different hPD-L1 levels showed prominent anti-tumor effect with significantly increased number of CD8+ cells and 4-1BB+ cells in the tumor. This anti-tumor activity was correlated with the proliferation (Ki-67+) of CD8+ T cells in the tumor microenvironment. Ex vivo assays utilizing patient-derived lung cancer organoids revealed that ABL503 (TJ-L14B) exhibits superior tumor-killing activity than that by benchmark PD-L1 antibody, Atezolizumab. In addition, cytokine release assay demonstrated that ABL503 (TJ-L14B) did not induce non-specific pro-inflammatory cytokine release by human PBMCs.ConclusionsOur data indicate that PD-L1 and 4-1BB dual targeting bispecific antibody, ABL503 (TJ-L14B), shows potent 4-1BB agonistic activity and anti-tumor effect in a PD-L1-dependent fashion concomitant with 4-1BB+/CD8+ T cell activation and proliferation to overcome limitations of PD-(L)1-targeted therapy while minimizing the risk of peripheral toxicity. The phase 1 clinical trial in the U.S. is currently ongoing in patients with locally advanced or metastatic solid tumors (NCT04762641).

Mepanipyrim and cyprodinil induce divergent temporal patterns of AhR-mediated responses in zebrafish (Danio rerio) embryos and larvae

Mepanipyrim and cyprodinil are widely used to control and/or prevent fungal diseases in fruit culture. They are widely detected in aquatic environment and numerous food commodities including fruit and fruit products. Different from TCDD, mepanipyrim and cyprodinil are more easily degraded and metabolized in the environment. However, the in vivo analysis of their metabolic dynamics is unclear and need to be further confirmed. In this study, zebrafish embryos were constantly exposed to 100 µg/L mepanipyrim or cyprodinil for 7 days. The temporal pattern of CYP1A and AhR2 expression and EROD enzyme activity at different time frames during embryonic and larval development of zebrafish were investigated. Our results showed that mepanipyrim and cyprodinil tend to accumulate in zebrafish during early embryonic developmental stages. Meanwhile, mepanipyrim and cyprodinil exposure could increase the expression level of cyp1a and ahr2 genes and EROD activity by a dynamic pattern in different developmental stages of zebrafish. Besides, their metabolites, which may accumulate in the zebrafish larvae, have strong AhR agonistic activity and showed strong AhR binding ability. Importantly, the risk of exposure to pesticides in embryo stage is huge, and should be paid more attention.

A systems biology model of junctional localization and downstream signaling of the Ang–Tie signaling pathway

The Ang–Tie signaling pathway is an important vascular signaling pathway regulating vascular growth and stability. Dysregulation in the pathway is associated with vascular dysfunction and numerous diseases that involve abnormal vascular permeability and endothelial cell inflammation. The understanding of the molecular mechanisms of the Ang–Tie pathway has been limited due to the complex reaction network formed by the ligands, receptors, and molecular regulatory mechanisms. In this study, we developed a mechanistic computational model of the Ang–Tie signaling pathway validated against experimental data. The model captures and reproduces the experimentally observed junctional localization and downstream signaling of the Ang–Tie signaling axis, as well as the time-dependent role of receptor Tie1. The model predicts that Tie1 modulates Tie2’s response to the context-dependent agonist Ang2 by junctional interactions. Furthermore, modulation of Tie1’s junctional localization, inhibition of Tie2 extracellular domain cleavage, and inhibition of VE-PTP are identified as potential molecular strategies for potentiating Ang2’s agonistic activity and rescuing Tie2 signaling in inflammatory endothelial cells.

Anti-Fn14 Antibody-Conjugated Nanoparticles Display Membrane TWEAK-Like Agonism

Conventional bivalent IgG antibodies targeting a subgroup of receptors of the TNF superfamily (TNFSF) including fibroblast growth factor-inducible 14 (anti-Fn14) typically display no or only very limited agonistic activity on their own and can only trigger receptor signaling by crosslinking or when bound to Fcγ receptors (FcγR). Both result in proximity of multiple antibody-bound TNFRSF receptor (TNFR) molecules, which enables engagement of TNFR-associated signaling pathways. Here, we have linked anti-Fn14 antibodies to gold nanoparticles to mimic the “activating” effect of plasma membrane-presented FcγR-anchored anti-Fn14 antibodies. We functionalized gold nanoparticles with poly-ethylene glycol (PEG) linkers and then coupled antibodies to the PEG surface of the nanoparticles. We found that Fn14 binding of the anti-Fn14 antibodies PDL192 and 5B6 is preserved upon attachment to the nanoparticles. More importantly, the gold nanoparticle-presented anti-Fn14 antibody molecules displayed strong agonistic activity. Our results suggest that conjugation of monoclonal anti-TNFR antibodies to gold nanoparticles can be exploited to uncover their latent agonism, e.g., for immunotherapeutic applications.

Protective Effects of Irbesartan, an Angiotensin Receptor Blocker with PPARγ Agonistic Activity, against Estradiol Benzoate-Induced Endometrial Hyperplasia and Atypia in Female Rats via Modulation of TNFα/Survivin Pathway

Endometrial hyperplasia (EH) is a common gynecological problem and may progress to carcinoma. Early detection and management of EH are mandatory for the prevention of endometrial cancer. Activation of the renin–angiotensin system and angiotensin II signaling are involved in the progression of precancerous and cancerous lesions. However, no studies have evaluated the role of this system in estradiol benzoate (EB)-induced EH and atypia. Irbesartan (IRB), an angiotensin II receptor blocker with peroxisome proliferator-activated receptor gamma (PPARγ) agonistic activity was administered (30 mg/kg/d) in EB-treated (60 µg/100 g bodyweight, intramuscularly, three times per week) or untreated rats for 4 weeks. Uterine weight changes, malondialdehyde, superoxide dismutase (SOD), tumor necrosis factor-alpha (TNFα), survivin, cleaved caspase 3, interleukin-10 (IL10), and PPARγ were measured in addition to undergoing histopathological examination. Results showed that EB-induced EH and atypia significantly increased the uterine body weight, malondialdehyde, TNFα, and survivin, accompanied with significantly decreased SOD, cleaved caspase 3, IL10, and PPARγ, with typical histopathological changes of EH and atypia. Coadministration of IRB significantly prevented EB-induced biochemical and histopathological changes. The protective effects of IRB may be attributed to its anti-inflammatory and antioxidant properties, reduction of survivin, and increased levels of cleaved caspase 3.