JITC Letter from the Editor - April 2019

Dear JITC Readers,

In the April edition of the JITC Digest, let me call your attention to the following five articles of special significance. First, “Anti-PD-1 therapy elevates Treg/Th balance and increases tumor cell pSmad3 that are both targeted by anti-TGF-beta antibody to promote durable rejection and immunity in squamous cell carcinomas,” by E. Dodagatta-Marri et al. details the development and characterization of a novel panel of murine syngeneic SCC lines created to reflect the heterogeneity of human lung cancer and its responses to anti-PD-1 and anti-TGF-beta therapies. This study demonstrates that anti-PD-1 not only initiates a tumor rejection program, but can also induce a competing TGF-beta-driven immuno-regulatory program in SCCs, effects that were cooperatively blocked by combined PD-1 and TGF-beta inhibition.

Next, “Collagen density regulates the activity of tumor-infiltrating T cells,” by Dorota E. Kuczek et al. reports the use of 3D culture assays to investigate the role of collagen density as a direct regulator of anti-cancer T cell activity. Such results identify a new immune modulatory mechanism dampening T cell activity in the tumor microenvironment, which could constitute a novel therapeutic target for enhancing immunotherapy efficacy.

Furthermore, the article, “Merger of dynamic two-photon and phosphorescence lifetime microscopy reveals dependence of lymphocyte motility on oxygen in solid and hematological tumors,” by Mateusz Rytelewski et al. presents a novel imaging approach developed to elucidate the effect of oxygen tension on the efficacy of anti-tumor immune therapies. Data presented here analyzes the relationship between lymphocyte motility and oxygen distribution using ‘Fast’ Scanning Two-photon Phosphorescence Lifetime Imaging Microscopy (FaST-PLIM), a bi-modal imaging regimen that merges high-resolution oxygen imaging with fluorescence-based cellular tracking in in vivo models.

“Mechanisms involved in IL-15 superagonist enhancement of anti-PD-L1 therapy,” by Karin M. Knudson et al. describes for the first time the anti-tumor efficacy of subcutaneously administered IL-15 superagonist N-803 in combination with anti-PD-L1 checkpoint blockade in murine triple negative breast and colon carcinoma models which are non- and/or minimally responsive to either monotherapy. This study provides rationale for further assessment of the clinical potential of combining N-803 with blockade of the PD-1/PD-L1 axis.

Finally, Anne Monette et al.’s article, “Immune-enrichment of non-small cell lung cancer baseline biopsies for multiplex profiling define prognostic immune checkpoint combinations for patient stratification,” propose a novel, tumor heterogeneity reducing procedure to extract information from small tumor biopsies for companion diagnostic (CDx) tests for immunotherapy of lung cancer. Developed from immune-dense regions of core needle biopsies from a baseline NSCLC cohort, this new CDx is shown to profile infiltrating immune cell subsets, ICPs, proliferation, and effector T cell markers to better stratify patients for checkpoint blockade combinations using baseline biospecimens of all sizes.

With best regards,

Pedro J. Romero, MD
Editor-in-Chief, Journal for ImmunoTherapy of Cancer

To view the entire April 2019 JITC Digest, please click here.