CCSG Pilot: Immunomodulatory Metabolic Function of Pembrolizumab in Human Macrophages

Grants and Contracts Details


Abstract Lung cancer is by far the leading cause of death among all cancers for both men and women in the U.S. Kentucky leads the nation in lung cancer incidence and mortality, and the statistics for the Appalachian population are much worse. Immunotherapy is one of the most promising strategies for advanced lung cancer therapy. The checkpoint inhibitor pembrolizumab (Pembro) was approved in 2016 as first]line therapy for advanced non]small cell lung cancer (NSCLC). This inhibitor is known to block programmed cell death 1 (PD]1) receptor interaction with its ligand PD]L1 in cytotoxic CD8 T]cells in the tumor microenvironment (TME), thereby preventing their apoptotic cell death and inhibition of the production of pro]inflammatory cytokines and anti]tumor effectors. However, variable efficacy, intolerable toxicity, and resistance are also known for this treatment, which calls for a better understanding of Pembrofs action in TME. Both PD]L1 and PD]1 are also expressed in macrophages (MƒÓ) including tumor]associated macrophages (TAM) in NSCLC. Their expression in MƒÓ can lead to apoptosis, reduced phagocytosis, immunosuppression, and tumor growth promotion. These intriguing reports raise a question regarding the functional mechanism of PD]1 and PD]L1 expression in MƒÓ. We have begun to address this question by investigating the effect of Pembro treatment on human PBMC]derived naive (M0) and differentially polarized MƒÓ (M(LPS+IFNƒÁ) (M1) and M(IL]4+IL]13) (M2) in 3D spheroid cultures with or without NSCLC A549 cell conditioned media (CM). The choice of 3D, instead of 2D, culturing with cancer cell CM is to enable TME factors such as cell]cell and cell]extracellular matrix (ECM). We found that Pembro and/or A549 CM altered phagocytotic activity, MYC expression, and M1]type cytokine release in polarized MƒÓ spheroids. The proto]oncogene MYC is known to modulate mouse MƒÓ polarization and metabolism but nothing is known for human MƒÓ spheroids. By using 13C6]glucose as tracer coupled with the Stable Isotope]Resolved Metabolomics (SIRM) approach, we saw that Pembro and/or A549 CM altered immunomodulatory (IM) metabolism including Gln/Glu uptake and glucose metabolism via glycolysis, Krebs cycle, and gluconeogenesis in polarized spheroids. These data strongly argue for a functional role of checkpoint proteins in modulating human MƒÓ function/metabolism and transcriptional control by MYC. Thus, in this pilot project, we will expand the preliminary work to fulfill two specific aims. SA1. To investigate the functional consequences of Pembro treatment in PBMC]derived MƒÓ/A549 spheroids and their co]cultures. Functional and detailed SIRM]informed metabolic responses will be related to key gene and protein expression changes for 6 healthy human subjects to build candidate gene regulatory network for Pembrofs action. SA2. To assess the role of MYC in mediating the Pembro and/or A549 coculture effect on IM metabolism and polarization of MƒÓ spheroids. The functional, metabolic, and gene/protein expression consequences of MYC suppression will be determined in human MƒÓ/A549 spheroids and their co]cultures to gain insights into MYCfs role in modulating human MƒÓ polarization, IM metabolism, and checkpoint protein function. This information can reveal new metabolic immunoregulators to be exploited for potentiating Pembro] or other checkpoint inhibitor]based immunotherapy.
Effective start/end date10/1/1812/31/19


  • National Cancer Institute


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