Search

Abstract Peritoneal carcinomatosis (PC) is a complex manifestation of abdominal cancers, with a poor prognosis and limited treatment options. Recent work identifying high concentrations of the cytokine interleukin-6 (IL-6) and its soluble receptor (sIL-6-Rα) in the peritoneal cavity of patients with PC has highlighted this pathway as an emerging potential therapeutic target. This review article provides a comprehensive overview of the current understanding of the potential role of IL-6 in the development and progression of PC. We discuss mechansims by which the IL-6 pathway may contribute to peritoneal tumor dissemination, mesothelial adhesion and invasion, stromal invasion and proliferation, and immune response modulation. Finally, we review the prospects for targeting the IL-6 pathway in the treatment of PC, focusing on common sites of origin, including ovarian, gastric, pancreatic, colorectal and appendiceal cancer, and mesothelioma.

Adoptive Cellular Therapy (ACT) is transitioning from experimental to standard of care. Limited specificities of chimeric antigen receptor T cells (CAR-T) are licensed drugs, with commercial products selling for ∼400,000 USD. Tumor infiltrating lymphocytes (TIL) can target multiple cell surface and intracellular tumor antigens. TIL have not been commercialized, due to complex logistics and cost. Our objective is to leverage a single standardized platform (Miltenyi Prodigy) for in-house ACT.We currently manufacture CD19 CAR-T under an FDA IND and are developing a virtually identical TIL protocol minus the lentiviral vector. TIL are manufactured from malignant pleural effusions rich in immune infiltrates. CD4+ and CD8+ cells are enriched and activated with anti-CD3/CD28 beads. CAR-T are transduced, and both CAR-T and TIL are expanded (IL-7/IL-15) for 5 days. The product is infused fresh, avoiding losses associated with cryopreservation and thawing.Developing and validating release tests (absence of replication competent virus, vector copy number, chimeric antigen receptor expression, endotoxin testing) posed an initial challenge. Having completed assay development, our manufacturing process, including release testing, can be performed for less than 1/10 the cost of commercial CAR-T.We expect that the platform that we have validated will be easily transitioned to new chimeric antigen receptor designs and specificities and will likewise be adaptable to TIL manufacture for the wide variety of cancers that metastasize to the pleura of peritoneum. Standardized in-house ACT manufacture may greatly reduce the cost of cellular immunotherapies, making it more widely available to patients.

Objective: The goal of this study was to determine whether antiIL-6Rα block (tocilizumab) will alter the pleural secretome and will diminish tumor-specific immune responses. Methodology: Pleural T cells were isolated from freshly drained pleural effusions (n=6). Autologous pleural tumor was expanded in vitro using the Mammary Epithelial Growth Medium (Lonza). Pleural T cells were stimulated using anti-CD3/CD28 Dynal beads and low dose IL-2 (60 Cetus U/ml) for 2,4,7, 14 or 21 days in the presence of tocilizumab for the last 48h (0, 0.35, 0.72, 1.43, 2.86 and 5.72ug/ml). Pleural T cell effectors were counted and plated on tumor targets at 12.5:1 E:T in the presence of tocilizumab. Results: Ex vivo expanded pleural T cells were effector-memory phenotype (CD45RA-CD27-) and were highly cytotoxic against autologous tumor (89-100%). The majority of CD8+ T cells were central memory (CD45RA-/CD27-) or effector memory (CD45RA+/CD27-); the majority co-expressed granzyme B, perforin, 20-60% expressed PD-1. Most CD4+ co-expressed granzyme B and perforin and were PD-1+, suggesting cytotoxic CD4+ T cells. The presence of tocilizumab reversed tumor EMT but did not alter cytotoxicity. Conclusion: We show that the IL-6/IL-6Rα axis is prominent in MPE, drives tumor growth and inhibits anti-tumor immunity. Pleural T cells are neither exhausted nor dysfunctional but are suppressed by the pleural environment. Ex vivo expanded MPE CD8 and CD4 T cells are highly cytotoxic against autologous tumor. Anti-IL-6Rα block reverses tumor EMT but does not inhibit effector responses.