A Phase Ib Study of Preoperative, Locoregional IRX-2 Cytokine Immunotherapy to Prime Immune Responses in Patients with Early-Stage Breast Cancer

PURPOSE

To evaluate the safety and feasibility of preoperative locoregional cytokine therapy (IRX-2 regimen) in early-stage breast cancer, and to evaluate for intratumoral and peripheral immunomodulatory activity.

PATIENTS AND METHODS

Sixteen patients with stage I-III early-stage breast cancer (any histology type) indicated for surgical lumpectomy or mastectomy were enrolled to receive preoperative locoregional immunotherapy with the IRX-2 cytokine biological (2 mL subcutaneous × 10 days to periareolar skin). The regimen also included single-dose cyclophosphamide (300 mg/m²) on day 1 to deplete T-regulatory cells and oral indomethacin to modulate suppressive myeloid subpopulations. The primary objective was to evaluate feasibility (i.e., receipt of therapy without surgical delays or grade 3/4 treatment-related adverse events). The secondary objective was to evaluate changes in stromal tumor-infiltrating lymphocyte score. The exploratory objective was to identify candidate pharmacodynamic changes for future study using a variety of assays, including flow cytometry, RNA and T-cell receptor DNA sequencing, and multispectral immunofluorescence.

RESULTS

Preoperative locoregional cytokine administration was feasible in 100% (n = 16/16) of subjects and associated with increases in stromal tumor-infiltrating lymphocytes (P < 0.001). Programmed death ligand 1 (CD274) was upregulated at the RNA (P < 0.01) and protein level [by Ventana PD-L1 (SP142) and immunofluorescence]. Other immunomodulatory effects included upregulation of RNA signatures of T-cell activation and recruitment and cyclophosphamide-related peripheral T-regulatory cell depletion.

CONCLUSIONS

IRX-2 is safe in early-stage breast cancer. Potentially favorable immunomodulatory changes were observed, supporting further study of IRX-2 in early-stage breast cancer and other malignancies.

CpG preconditioning regulates miRNA expression that modulates genomic reprogramming associated with neuroprotection against ischemic injury

Cytosine-phosphate-guanine (CpG) preconditioning reprograms the genomic response to stroke to protect the brain against ischemic injury. The mechanisms underlying genomic reprogramming are incompletely understood. MicroRNAs (miRNAs) regulate gene expression; however, their role in modulating gene responses produced by CpG preconditioning is unknown. We evaluated brain miRNA expression in response to CpG preconditioning before and after stroke using microarray. Importantly, we have data from previous gene microarrays under the same conditions, which allowed integration of miRNA and gene expression data to specifically identify regulated miRNA gene targets. CpG preconditioning did not significantly alter miRNA expression before stroke, indicating that miRNA regulation is not critical for the initiation of preconditioning-induced neuroprotection. However, after stroke, differentially regulated miRNAs between CpG- and saline-treated animals associated with the upregulation of several neuroprotective genes, implicating these miRNAs in genomic reprogramming that increases neuroprotection. Statistical analysis revealed that the miRNA targets were enriched in the gene population regulated in the setting of stroke, implying that miRNAs likely orchestrate this gene expression. These data suggest that miRNAs regulate endogenous responses to stroke and that manipulation of these miRNAs may have the potential to acutely activate novel neuroprotective processes that reduce damage.

Abstract TP255: Interferon-Induced Peptide With Tetratricopeptide Repeats 1 Is a Key Mediator of Neuroprotection Induced by Preconditioning

Introduction: Preconditioning is the phenomenon whereby a low dose of a harmful stimulus provides robust protection against injury due to subsequent cerebral ischemia. We have evaluated transcriptional responses in three distinct preconditioning paradigms [lipopolysaccharide (LPS), CpG, brief ischemia] to create an inferred network of the neuroprotective genomic responses to stroke in mice. Topological analysis of this network identified interferon-induced peptide with tetratricopeptide repeats 1 (IFIT1) as a key transition point between clusters of genes, which suggests that IFIT1 is significant in this biological process. IFIT1 has been shown to function as a regulator of protein translation and transcription factor activity, although a role in ischemic injury has not been identified. We hypothesized that IFIT1 is required for neuroprotection against ischemic injury in the setting of preconditioning.

Methods: We analyzed the regulation of IFIT1 and its inferred first-order network (genes directly linked to IFIT1) using mouse brain microarray data 3, 24, and 72 h following preconditioning and 3 and 24 h following middle cerebral artery occlusion (MCAO, n=4/treatment/timepoint, ~100 microarrays). In addition, IFIT1 deficient mice were preconditioned with LPS 72 h prior to MCAO and percent infarct was determined.

Results: Network analysis revealed that IFIT1 and its first-order network are induced 24 h following stroke in preconditioned mice but not in mice given a stroke in the absence of preconditioning. This result suggests that IFIT1’s first-order network is associated with neuroprotection. Interestingly, IFIT1’s first-order network contains several interferon-associated genes, which are known to contribute to neuroprotection induced by preconditioning. Further support for a fundamental role for IFIT1 is evinced by our finding that IFIT1 deficient mice preconditioned with LPS are not protected against subsequent MCAO.

Conclusion: IFIT1 is essential for neuroprotection induced by LPS preconditioning and may play an instrumental role in mediating an endogenous neuroprotective response to stroke.

Poly-ICLC preconditioning protects the blood-brain barrier against ischemic injury in vitro through type I interferon signaling

Preconditioning with a low dose of harmful stimulus prior to injury induces tolerance to a subsequent ischemic challenge resulting in neuroprotection against stroke. Experimental models of preconditioning primarily focus on neurons as the cellular target of cerebral protection, while less attention has been paid to the cerebrovascular compartment, whose role in the pathogenesis of ischemic brain injury is crucial. We have shown that preconditioning with polyinosinic polycytidylic acid (poly-ICLC) protects against cerebral ischemic damage. To delineate the mechanism of poly-ICLC protection, we investigated whether poly-ICLC preconditioning preserves the function of the blood-brain barrier (BBB) in response to ischemic injury. Using an in vitro BBB model, we found that poly-ICLC treatment prior to exposure to oxygen-glucose deprivation maintained the paracellular and transcellular transport across the endothelium and attenuated the drop in transendothelial electric resistance. We found that poly-ICLC treatment induced interferon (IFN) β mRNA expression in astrocytes and microglia and that type I IFN signaling in brain microvascular endothelial cells was required for protection. Importantly, this implicates a potential mechanism underlying neuroprotection in our in vivo experimental stroke model, where type I IFN signaling is required for poly-ICLC-induced neuroprotection against ischemic injury. In conclusion, we are the first to show that preconditioning with poly-ICLC attenuates ischemia-induced BBB dysfunction. This mechanism is likely an important feature of poly-ICLC-mediated neuroprotection and highlights the therapeutic potential of targeting BBB signaling pathways to protect the brain against stroke.

Toll-like receptor 7 preconditioning induces robust neuroprotection against stroke by a novel type I interferon-mediated mechanism

BACKGROUND AND PURPOSE

Systemic administration of Toll-like receptor (TLR) 4 and TLR9 agonists before cerebral ischemia have been shown to reduce ischemic injury by reprogramming the response of the brain to stroke. Our goal was to explore the mechanism of TLR-induced neuroprotection by determining whether a TLR7 agonist also protects against stroke injury.

METHODS

C57Bl/6, TNF(-/-), interferon (IFN) regulatory factor 7(-/-), or type I IFN receptor (IFNAR)(-/-) mice were subcutaneously administered the TLR7 agonist Gardiquimod (GDQ) 72 hours before middle cerebral artery occlusion. Infarct volume and functional outcome were determined after reperfusion. Plasma cytokine responses and induction of mRNA for IFN-related genes in the brain were measured. IFNAR(-/-) mice also were treated with the TLR4 agonist (lipopolysaccharide) or the TLR9 agonist before middle cerebral artery occlusion and infarct volumes measured.

RESULTS

The results show that GDQ reduces infarct volume as well as functional deficits in mice. GDQ pretreatment provided robust neuroprotection in TNF(-/-) mice, indicating that TNF was not essential. GDQ induced a significant increase in plasma IFNα levels and both IRF7(-/-) and IFNAR(-/-) mice failed to be protected, implicating a role for IFN signaling in TLR7-mediated protection.

CONCLUSIONS

Our studies provide the first evidence that TLR7 preconditioning can mediate neuroprotection against ischemic injury. Moreover, we show that the mechanism of protection is unique from other TLR preconditioning ligands in that it is independent of TNF and dependent on IFNAR.