Ex Vivo Profiling of PD-1 Blockade Using Organotypic Tumor Spheroids

Abstract

systems that incorporate features of the tumor microenvironment and model the dynamic response to immune checkpoint blockade (ICB) may facilitate efforts in precision immuno-oncology and the development of effective combination therapies. Here, we demonstrate the ability to interrogate response to ICB using murine- and patient-derived organotypic tumor spheroids (MDOTS/PDOTS). MDOTS/PDOTS isolated from mouse and human tumors retain autologous lymphoid and myeloid cell populations and respond to ICB in short-term three-dimensional microfluidic culture. Response and resistance to ICB was recapitulated using MDOTS derived from established immunocompetent mouse tumor models. MDOTS profiling demonstrated that TBK1/IKKε inhibition enhanced response to PD-1 blockade, which effectively predicted tumor response Systematic profiling of secreted cytokines in PDOTS captured key features associated with response and resistance to PD-1 blockade. Thus, MDOTS/PDOTS profiling represents a novel platform to evaluate ICB using established murine models as well as clinically relevant patient specimens. Resistance to PD-1 blockade remains a challenge for many patients, and biomarkers to guide treatment are lacking. Here, we demonstrate feasibility of profiling of PD-1 blockade to interrogate the tumor immune microenvironment, develop therapeutic combinations, and facilitate precision immuno-oncology efforts..

A Paradigm Shift in Cancer Immunotherapy: From Enhancement to Normalization

“…We then need better in vivo models to characterize the dominance of the different immune pathways in a patient TME and the effect of their modulation. Humanized mouse models or explant 3D culture models may provide support in this way (Jenkins et al, 2018; Sanmamed et al, 2016; Zitvogel et al, 2016). …”

Overcoming Resistance to Dual Innate Immune and MEK Inhibition Downstream of KRAS

“…Recently, more potent and specific TBK1 (compound 1) and BET (GS-626510) inhibitors have been described (Jenkins et al, 2018; Shi et al, 2016). We therefore utilized an aggressive KL patient-derived xenograft (PDX) model (DFCI-366) to design a combination therapy schedule for potential future translation to the clinic.…”

“…Finally, we also used recently described potent and selective TBK1 and BET inhibitors (Jenkins et al, 2018; Shi et al, 2016) as tool compounds to develop a therapeutic strategy with translatable potential for KRAS-driven NSCLC patients. The alternating doublet strategy minimizes the toxicity of inhibiting each target, limits DDI, and also provides a faster path to the clinic compared with triple combination therapies that require complex dose escalation schedules.…”

Mapping the Immune Landscape of Clear Cell Renal Cell Carcinoma by Single-Cell RNA-seq

“…For example, in the study of CD8 T cell states associated with response to PD-1 blockade, Sade-Feldman and colleagues validated TCF7 protein expression in CD8 T cells by multiplexed immunofluorescence (20). Thirdly, functional profiling of specific cell states in a tumor model will be needed to define the roles and regulation of the identified lymphoid and myeloid sub-populations to tumor initiation, progression, metastasis, and response/resistance to anti-angiogenic and immune therapies in ccRCC (20,56). Nevertheless, the immune landscape of ccRCC reported here will provide a valuable resource to accelerate research of the TME with the ultimate goal of discovering novel transcriptomic biomarkers and therapeutic targets.…”