Investigation of the Potential of Immunomodulating Agent with PD-1 Blockade Therapy for Modulating Immune Exhaustion in NSCLC Open Access

Zhao, Jianing (Spring 2024)

Permanent URL: https://etd.library.emory.edu/concern/etds/9g54xj99z?locale=en
Published

Abstract

Background

Current PD-1 and PD-L1 blockade therapies for non-small cell lung cancer (NSCLC) and other solid tumors face limitations despite their efficacy in improving patient survival rates. These limitations include immune-related adverse events (irAEs), development of resistance, and tumor relapse. We propose that baricitinib, an immunomodulatory agent inhibiting Jak1 and Jak2, may reduce the expression of pro-inflammatory markers and reverse immune exhaustion that drive the tumor microenvironment and limits success of the existing standard of care. This potential synergy with PD-1 and PD-L1 inhibitors could induce tumor regression and improve patient outcomes.

Methods

Our study focuses on investigating T cell responses to baricitinib, pembrolizumab, and their combination treatment. Primary PBMCs isolated from whole blood that underwent pretreatment with cancer-conditioned media (CCM) to induce immune dysregulation. The cells were then treated with physiological concentrations of baricitinib, pembrolizumab, and their combination. PD-1 and PD-L1 expression on CD4+ and CD8+ T cells were quantified using flow cytometry (Attune Nxt, Invitrogen) and analyzed using FlowJo software.

Results

Our data revealed that CCM activated T cells by increasing PD-1 and PD-L1 expression. Baricitinib significantly suppressed CCM-induced T cell activation by lowering PD-1 and PD-L1 expression. While pembrolizumab did not reduce PD-L1 expression, it decreased the percentage of PD-1+ T cells. Further validation is required to confirm whether this finding is due to lowered PD-1 expression on T cells or competition binding between PD-1 antibody and pembrolizumab. The combination therapy showed statistically significant differences in reducing PD-1 expression compared to single drugs, albeit with subtle absolute changes in marker expression levels.

Conclusions

Our results suggest that baricitinib can significantly reduce T cell activation and exhaustion markers conferred upon exposure to cancer-conditioned environment. This study provides preliminary evidence of baricitinib's therapeutic potential in combination therapy with PD-1 blockade by addressing irAEs, reversing immune exhaustion and dysregulation, and potentially offer new mechanistic approaches to improve clinical outcomes in individuals with PD-1 blockade indicated malignancies.

Table of Contents

Introduction 1

Methods 7

Preparation of cancer-conditioned media (CCM) 7

Isolation of primary PBMC from whole blood 7

In vitro treatment of primary PBMCs with baricitinib and pembrolizumab 7

Flow cytometry analysis of surface markers 9

PD-1 antibody competitive binding assay 12

T cell activation via anti-CD3 and anti-CD28 13

Results and Analysis 14

CCM induced the upregulation of PD-1 and PD-L1 expression on T cells 14

Baricitinib, pembrolizumab, and combination downregulated functional PD-1 expression on CD4+ and CD8+ T cells 16

Baricitinib and combination treatment downregulated functional PD-L1 expression on CD4+ and CD8+ T cells 18

No significant conclusions can be drawn from the mean fluorescence intensity data 20

Discussion and Conclusions 21

Limitations and future directions 24

References 27

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