Evaluation of single cell co-expression profiles of immune checkpoint therapeutic targets in the tumor microenvironment of Non-small Cell Lung Cancer


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Bradley Spencer-Dene1,Faraia Shah1,Na Li1,Jeff Kim1,Xiao-Jun Ma1,Emily Park1
1Advanced Cell Diagnostics

Abstract

Background

Immune-checkpoint inhibitors have demonstrated therapeutic efficacy and durable response for several tumor types including non-small cell lung cancer (NSCLC).  In addition to efforts on biomarkers to identify responsive tumors, adaptive resistance to individual checkpoint blockade suggests the need to target multiple immune checkpoints.

Method

We evaluated single cell expression profiles of therapeutic checkpoint targets in the tumor microenvironment (TME) of 56 archived NSCLC FFPE tissues. Applying RNAscope® in-situ hybridization assays, specific checkpoint target molecules are visualized at single molecule detection sensitivity.

Results

Here we report visual representation of immune checkpoint targets expressed in the TME. The evaluation of PD-L1 expression in each tumor tissue showed a dynamic expression of PD-L1 mRNAs in the tumor and stromal regions. Duplex RNAscope analysis of PD1 (or PD-L1) with other therapeutic targets such as TIM3 or LAG3 revealed co- expression of multiple checkpoint markers in the same tumor environment, primarily in the highly inflamed tumors.  Most importantly, single cell co-localization of therapeutic targets are represented and quantified in inflamed and non-inflamed tumors.

Conclusion

The expression and co-localization of multiple therapeutic immune checkpoint targets are visualized and quantified in single cells within intact tissues, suggesting potential resistance mechanisms which may help guide in stratifying patients for different combinatorial approaches.