Human plasma cells engineered to secrete bispecifics drive effective in vivo leukemia killing.

Bispecific antibodies are an important tool for the management and treatment of acute leukemias. As a next step toward clinical translation of engineered plasma cells, we describe approaches for secretion of bispecific antibodies by human plasma cells. We show that human plasma cells expressing either fragment crystallizable domain-deficient anti-CD19 × anti-CD3 (blinatumomab) or anti-CD33 × anti-CD3 bispecific antibodies mediate T cell activation and direct T cell killing of B acute lymphoblastic leukemia or acute myeloid leukemia cell lines in vitro.

tracking of generated Zr-oxine labeled plasma cells by PET in a non-human primate model.

B cells are an attractive platform for engineering to produce protein-based biologics absent in genetic disorders, and potentially for the treatment of metabolic diseases and cancer. As part of pre-clinical development of B cell medicines, we demonstrate a method to collect, expand, differentiate, radioactively label, and track adoptively transferred non-human primate (NHP) B cells. These cells underwent 10- to 15-fold expansion, initiated IgG class switching, and differentiated into antibody secreting cells.

Host-functionalization of macrin nanoparticles to enable drug loading and control tumor-associated macrophage phenotype.

Macrophages are critical regulators of the tumor microenvironment and often present an immuno-suppressive phenotype, supporting tumor growth and immune evasion. Promoting a robust pro-inflammatory macrophage phenotype has emerged as a therapeutic modality that supports tumor clearance, including through synergy with immune checkpoint therapies. Polyglucose nanoparticles (macrins), which possess high macrophage affinity, are useful vehicles for delivering drugs to macrophages, potentially altering their phenotype.

Macrophage imaging and subset analysis using single-cell RNA sequencing.

Macrophages have been associated with drug response and resistance in diverse settings, thus raising the possibility of using macrophage imaging as a companion diagnostic to inform personalized patient treatment strategies. Nanoparticle-based contrast agents are especially promising because they efficiently deliver fluorescent, magnetic, and/or radionuclide labels by leveraging the intrinsic capacity of macrophages to accumulate nanomaterials in their role as professional phagocytes. Unfortunately, current clinical imaging modalities are limited in their ability to quantify broad molecular programs that may explain (a) which particular cell subsets a given imaging agent is actually labeling, and (b) what mechanistic role those cells play in promoting drug response or resistance.

Phase II Trial of IL-12 Plasmid Transfection and PD-1 Blockade in Immunologically Quiescent Melanoma.

Purpose: Tumors with low frequencies of checkpoint positive tumor-infiltrating lymphocytes (cpTIL) have a low likelihood of response to PD-1 blockade. We conducted a prospective multicenter phase II trial of intratumoral plasmid IL-12 (tavokinogene telseplasmid; "tavo") electroporation combined with pembrolizumab in patients with advanced melanoma with low frequencies of checkpoint positive cytotoxic lymphocytes (cpCTL).

Patients And Methods: Tavo was administered intratumorally days 1, 5, and 8 every 6 weeks while pembrolizumab (200 mg, i.

LTX-315 sequentially promotes lymphocyte-independent and lymphocyte-dependent antitumor effects.

LTX-315 is an oncolytic peptide that has antitumor efficacy in mice grafted with various tumor cell lines and is currently being tested in phase II clinical trials. Here we aimed to further evaluate LTX-315 in conditional genetic mouse models of cancer that typically resist current treatment options and to better understand the drug's mode of action . We report LTX-315 mediates profound antitumor effects against and -driven melanoma and delays the progression of and driven soft tissue sarcoma in mice.

Imaging of cancer lipid metabolism in response to therapy.

Lipids represent a diverse array of molecules essential to the cell's structure, defense, energy, and communication. Lipid metabolism can often become dysregulated during tumor development. During cancer therapy, targeted inhibition of cell proliferation can likewise cause widespread and drastic changes in lipid composition.

TLR7/8-agonist-loaded nanoparticles promote the polarization of tumour-associated macrophages to enhance cancer immunotherapy.

Tumour-associated macrophages are abundant in many cancers, and often display an immune-suppressive M2-like phenotype that fosters tumour growth and promotes resistance to therapy. Yet, macrophages are highly plastic and can also acquire an anti-tumorigenic M1-like phenotype. Here, we show that R848, an agonist of the toll-like receptors TLR7 and TLR8 identified in a morphometric-based screen, is a potent driver of the M1 phenotype in vitro and that R848-loaded β-cyclodextrin nanoparticles (CDNP-R848) lead to efficient drug delivery to tumour-associated macrophages in vivo.

Arg1 expression defines immunosuppressive subsets of tumor-associated macrophages.

Tumor-associated macrophages (TAM) have attracted attention as they can modulate key cancer-related activities, yet TAM represent a heterogenous group of cells that remain incompletely characterized. In growing tumors, TAM are often referred to as M2-like macrophages, which are cells that display immunosuppressive and tumorigenic functions and express the enzyme arginase 1 (Arg1). Here we combined high resolution intravital imaging with single cell RNA seq to uncover the topography and molecular profiles of immunosuppressive macrophages in mice.

Successful Anti-PD-1 Cancer Immunotherapy Requires T Cell-Dendritic Cell Crosstalk Involving the Cytokines IFN-γ and IL-12.

Anti-PD-1 immune checkpoint blockers can induce sustained clinical responses in cancer but how they function in vivo remains incompletely understood. Here, we combined intravital real-time imaging with single-cell RNA sequencing analysis and mouse models to uncover anti-PD-1 pharmacodynamics directly within tumors. We showed that effective antitumor responses required a subset of tumor-infiltrating dendritic cells (DCs), which produced interleukin 12 (IL-12).

Recording the wild lives of immune cells.

Intravital microscopic imaging can uncover fundamental aspects of immune cell behavior in real time in both healthy and pathological states. Here, we discuss approaches for single-cell imaging of adaptive and innate immune cells to explore how they migrate, communicate, and mediate regulatory or effector functions in various tissues throughout the body. We further review how intravital single-cell imaging can be used to study drug effects on immune cells.

IRF3 and type I interferons fuel a fatal response to myocardial infarction.

Interferon regulatory factor 3 (IRF3) and type I interferons (IFNs) protect against infections and cancer, but excessive IRF3 activation and type I IFN production cause autoinflammatory conditions such as Aicardi-Goutières syndrome and STING-associated vasculopathy of infancy (SAVI). Myocardial infarction (MI) elicits inflammation, but the dominant molecular drivers of MI-associated inflammation remain unclear. Here we show that ischemic cell death and uptake of cell debris by macrophages in the heart fuel a fatal response to MI by activating IRF3 and type I IFN production.

Prediction of Anti-cancer Nanotherapy Efficacy by Imaging.

Anticancer nanotherapeutics have shown mixed results in clinical trials, raising the questions of whether imaging should be used to i) identify patients with a higher likelihood of nanoparticle accumulation, ii) assess nanotherapeutic efficacy before traditional measures show response, and iii) guide adjuvant treatments to enhance therapeutic nanoparticle (TNP) delivery. Here we review the use of a clinically approved MRI nanoparticle (ferumoxytol, FMX) to predict TNP delivery and efficacy. It is becoming increasingly apparent that nanoparticles used for imaging, despite clearly distinct physicochemical properties, often co-localize with TNP in tumors.

In vivo imaging reveals a tumor-associated macrophage-mediated resistance pathway in anti-PD-1 therapy.

Monoclonal antibodies (mAbs) targeting the immune checkpoint anti-programmed cell death protein 1 (aPD-1) have demonstrated impressive benefits for the treatment of some cancers; however, these drugs are not always effective, and we still have a limited understanding of the mechanisms that contribute to their efficacy or lack thereof. We used in vivo imaging to uncover the fate and activity of aPD-1 mAbs in real time and at subcellular resolution in mice. We show that aPD-1 mAbs effectively bind PD-1 tumor-infiltrating CD8 T cells at early time points after administration.

Near infrared fluorescent imaging of choline kinase alpha expression and inhibition in breast tumors.

Choline kinase alpha (ChoKα) overexpression is associated with an aggressive tumor phenotype. ChoKα inhibitors induce apoptosis in tumors, however validation of their specificity is difficult in vivo. We report the use of optical imaging to assess ChoKα status in cells and in vivo using JAS239, a carbocyanine-based ChoKα inhibitor with inherent near infrared fluorescence.

Choline kinase alpha-Putting the ChoK-hold on tumor metabolism.

It is well established that lipid metabolism is drastically altered during tumor development and response to therapy. Choline kinase alpha (ChoKα) is a key mediator of these changes, as it represents the first committed step in the Kennedy pathway of phosphatidylcholine biosynthesis and ChoKα expression is upregulated in many human cancers. ChoKα activity is associated with drug resistant, metastatic, and malignant phenotypes, and represents a robust biomarker and therapeutic target in cancer.

Quantification of tumor fluorescence during intraoperative optical cancer imaging.

Intraoperative optical cancer imaging is an emerging technology in which surgeons employ fluorophores to visualize tumors, identify tumor-positive margins and lymph nodes containing metastases. This study compares instrumentation to measure tumor fluorescence. Three imaging systems (Spectropen, Glomax, Flocam) measured and quantified fluorescent signal-to-background ratios (SBR) in vitro, murine xenografts, tissue phantoms and clinically.

Magnetic resonance spectroscopy for detection of choline kinase inhibition in the treatment of brain tumors.

Abnormal choline metabolism is a hallmark of cancer and is associated with oncogenesis and tumor progression. Increased choline is consistently observed in both preclinical tumor models and in human brain tumors by proton magnetic resonance spectroscopy (MRS). Thus, inhibition of choline metabolism using specific choline kinase inhibitors such as MN58b may be a promising new strategy for treatment of brain tumors.

Direct inhibition of choline kinase by a near-infrared fluorescent carbocyanine.

Choline kinase alpha (ChoK) expression is increasingly being recognized as an important indicator of breast cancer prognosis; however, previous efforts to noninvasively measure ChoK status have been complicated by the spectral limitations of in vivo magnetic resonance spectroscopy (MRS) and the complex network of enzymes involved in choline metabolism. The most effective ChoK inhibitors are symmetric and contain quaternary ammonium groups within heterocyclic head groups connected by an aliphatic spacer. Characterization of these bis-pyridinium and bis-quinolinium compounds has led to phase I clinical trials to assess small-molecule inhibitors of ChoK for solid tumor treatment.