Anti-DEspR antibody treatment improves survival and reduces neurologic deficits in a hypertensive, spontaneous intracerebral hemorrhage (hsICH) rat model

Progressive secondary brain injury-induced by dysregulated neuroinflammation in spontaneous intracerebral hemorrhage (sICH)-underlies high sICH-mortality and remains without FDA-approved pharmacotherapy. Clinical insight that hematoma-directed interventions do not improve mortality prioritizes resolving acute secondary brain injury in sICH. As neutrophils are implicated in sICH secondary brain injury, we tested whether inhibition of a rogue neutrophil-subset expressing the dual endothelin-1/signal peptide receptor (DEspR) and associated with secondary tissue injury, DEspR+ CD11b+ immunotype, will attenuate mortality in a hypertensive-sICH (hsICH) rat model. We confirmed sICH-related deaths in hsICH-rats by T2*-weighted 9.4 T MRI and DEspR+ neutrophils in hsICH-rat brain perihematomal areas by immunostaining. At acute sICH, anti-DEspR muIgG1-antibody, mu10a3, treatment increased median survival in hsICH rats vs controls (p < 0.0001). In pre-stroke sICH, weekly 10a3-treatment did not predispose to infection and delayed sICH-onset vs controls (p < 0.0001). As potential sICH-therapeutic, we tested humanized anti-DEspR IgG4^S228P-mAb, hu6g8. In vitro, hu6g8 reversed delayed-apoptosis in DEspR+ CD11b+ neutrophils. In vivo, hu6g8 increased median survival and reduced neurologic symptoms in male/female hsICH-rats vs controls (p < 0.0001). Altogether, preclinical efficacy of inhibition of DEspR+ CD11b+ neutrophils in acute sICH-without infection complications, supports the potential of anti-DEspR therapy in sICH. Data provide basis for clinical study of DEspR+ CD11b+ neutrophil-subset in sICH patients.

“Rogue” neutrophil-subset [DEspR+CD11b+/CD66b+] immunotype is an actionable therapeutic target for neutrophilic inflammation-mediated tissue injury – studies in human, macaque and rat LPS-inflammation models

Background and objective

The correlation (Rs > 0.7) of neutrophils expressing the dual endothelin1/signal peptide receptor (DEspR+CD11b+/CD66b+) with severity of hypoxemia (SF-ratio) and multi-organ failure (SOFA-score) in patients with acute respiratory distress syndrome (ARDS) suggest the hypothesis that the DEspR+ neutrophil-subset is an actionable therapeutic target in ARDS. To test this hypothesis, we conducted in vivo studies to validate DEspR+ neutrophil-subset as therapeutic target and test efficacy of DEspR-inhibition in acute neutrophilic hyperinflammation models.

Methods

We performed tests in lipopolysaccharide (LPS)-induced acute neutrophilic inflammation in three species – human, rhesus macaque, rat – with increasing dose-dependent severity. We measured DEspR+CD66b+ neutrophils in bronchoalveolar lavage fluid (BALF) in healthy volunteers (HVs) 24-hours after segmental LPS-challenge by ChipCytometry, and DEspR+CD11b+ neutrophils in whole blood and BALF in an LPS-induced transient acute lung injury (ALI) model in macaques. We determined anti-DEspR antibody efficacy in vivo in LPS-ALI macaque model and in high-mortality LPS-induced encephalopathy in hypertensive rats.

Results

ChipCytometry detected increased BALF total neutrophil and DEspR+CD66b+ neutrophil counts after segmental LPS-challenge compared to baseline (P =0.034), as well as increased peripheral neutrophil counts and neutrophil-lymphocyte ratio (NLR) compared to pre-LPS level (P <0.05). In the LPS-ALI macaque model, flow cytometry detected increased DEspR+ and DEspR[-] neutrophils in BALF, which was associated with moderate-severe hypoxemia. After determining pharmacokinetics of single-dose anti-DEspR[hu6g8] antibody, one-time pre-LPS anti-DEspR treatment reduced hypoxemia (P =0.03) and neutrophil influx into BALF (P =0.0001) in LPS-ALI vs vehicle mock-treated LPS-ALI macaques. Ex vivo live cell imaging of macaque neutrophils detected greater “intrinsic adhesion to hard-surface” in DEspR+ vs DEspR[-] neutrophils (P <0.001). Anti-DEspR[hu6g8] antibody abrogated intrinsic high adhesion in DEspR+ neutrophils, but not in DEspR[-] neutrophils (P <0.001). In the LPS-encephalopathy rat model, anti-DEspR[10a3] antibody treatment increased median survival (P =0.0007) and exhibited brain target engagement and bioeffects.

Conclusion

Detection of increased DEspR+ neutrophil-subset in human BALF after segmental LPS-challenge supports the correlation of circulating DEspR+ neutrophil counts with severity measure (SOFA-score) in ARDS. Efficacy and safety of targeted inhibition of DEspR+CD11b+ neutrophil-subset in LPS-induced transient-ALI and high-mortality encephalopathy models identify a potential therapeutic target for neutrophil-mediated secondary tissue injury.

Humanized anti-DEspR IgG4S228P antibody increases overall survival in a pancreatic cancer stem cell-xenograft peritoneal carcinomatosis ratnu/nu model

BACKGROUND

Pancreatic peritoneal carcinomatosis (PPC), with the worst median overall-survival (mOS), epitomizes the incurability of metastatic cancer. Cancer stem cells (CSCs) underpin this incurability. However, inhibitors of CSC-stemness fail to increase mOS in cancer patients despite preclinical tumor-reduction. This shortfall reinforces that preclinical efficacy should be defined by increased mOS in the presence of cancer comorbidities, CSC-heterogeneity and plasticity. The primary objectives of this study are: to test the dual endothelin-1/signal peptide receptor, DEspR, as a nodal therapeutic target in PPC, given DEspR induction in anoikis-resistant pancreatic CSCs, and to validate humanized anti-DEspR antibody, hu-6g8, as a potential therapeutic for PPC.

METHODS

We used heterogeneous pools of CSCs selected for anoikis resistance from reprogrammed Panc1 and MiaPaCa2 tumor cells (TCs), and adherent TCs reprogrammed from CSCs (cscTCs). We used multiple anti-DEspR blocking antibodies (mAbs) with different epitopes, and a humanized anti-DEspR recombinant mAb cross-reactive in rodents and humans, to test DEspR inhibition effects. We measured DEspR-inhibition efficacy on multiple prometastatic CSC-functions in vitro, and on tumorigenesis and overall survival in a CSC-derived xenograft (CDX) nude rat model of PPC with comorbidities.

RESULTS

Here we show that DEspR, a stress-survival receptor, is present on subsets of PDAC Panc1-TCs, TC-derived CSCs, and CSC-differentiated TCs (cscTCs), and that DESpR-inhibition decreases apoptosis-resistance and pro-metastatic mesenchymal functions of CSCs and cscTCs in vitro. We resolve the DNA-sequence/protein-function discordance by confirming ADAR1-RNA editing-dependent DEspR-protein expression in Panc1 and MiaPaCa2 TCs. To advance DEspR-inhibition as a nodal therapeutic approach for PPC, we developed and show improved functionality of a recombinant, humanized anti-DEspR IgG4S228P antibody, hu-6g8, over murine precursor anti-DEspR mabs. Hu-6g8 internalizes and translocates to the nucleus colocalized with cyto-nuclear shuttling galectins-1/3, and induces apoptotic cell changes. DEspR-inhibition blocks transperitoneal dissemination and progression to peritoneal carcinomatosis of heterogeneous DEspR±/CD133 ± Panc1-derived CSCs in xenografted nude rats, improving mOS without chemotherapy-like adverse effects. Lastly, we show DEspR expression in Stage II-IV primary and invasive TCs in the stroma in PDAC-patient tumor arrays.

CONCLUSION

Collectively, the data support humanized anti-DEspR hu-6g8 as a potential targeted antibody-therapeutic with promising efficacy, safety and prevalence profiles for PPC patients.