Distinct tumor microenvironments of lytic and blastic bone metastases in prostate cancer patients

Abstract

The most common metastatic lesions of prostate cancer are in bone and can be classified into three distinct pathology subtypes: lytic, blastic, and an indeterminate mixture of both. We investigated a cohort of decalcified formalin-fixed and paraffin-embedded (FFPE) patient specimens from the bone that contained metastatic prostate cancer with lytic or blastic features. These tissue sections were utilized for immunohistochemistry (IHC) staining, isolation of RNA for gene expression, and Digital Spatial Profiling (DSP) of changes in both the tumor and microenvironment. A diverse set of unique immune cell populations and signaling pathways to both lytic and blastic types of prostate cancer metastases were present. In blastic lesions immune cells were enriched for pSTAT3 and components of the JAK-STAT pathway. In lytic-type lesions, immune cells were enriched for pAKT activity and components of the PI3K-AKT pathway. Enrichment for immune checkpoints including PD-L1, B7-H4, OX40L, and IDO-1 were identified in blastic prostate cancer, providing new therapeutic targets for patients with bone metastases. Biopsies could guide selection of patients into appropriate therapeutic interventions based on protein levels and RNA expression of desired targets in metastatic disease. Molecular pathology has been an excellent complement to the diagnosis, treatment, and management of primary tumors and could be successfully extended to patients with metastatic lesions.

Spatially-resolved quantification of proteins in triple negative breast cancers reveals differences in the immune microenvironment associated with prognosis

“…NanoString DSP is a unique method that allows for multiplexed protein quantification in clinical patient samples [11][12][13][14][15] . The method is gaining traction in the immune oncology environment and has been used to develop signatures that are predictive of patient response to immune checkpoint inhibitors 22,23 .…”

“…Laser capture microdissection (LCM) is one method that can be used to isolate cell types and quantify protein and gene expression in distinct populations of cells, though it is technically challenging and difficult to scale 8 . NanoString Digital Spatial Profiling (DSP) is a highly multiplexed method that allows for protein quantification in spatially resolved, morphologically distinct areas within a single FFPE tissue section 9,[11][12][13][14][15] . This method utilizes UV-photocleavable oligonucleotides that are conjugated to primary antibodies [13][14][15] .…”

“…NanoString Digital Spatial Profiling (DSP) is a highly multiplexed method that allows for protein quantification in spatially resolved, morphologically distinct areas within a single FFPE tissue section 9,[11][12][13][14][15] . This method utilizes UV-photocleavable oligonucleotides that are conjugated to primary antibodies [13][14][15] . After incubation with a multiplexed cocktail of primary antibodies, oligonucleotides are cleaved in regions of interest (ROIs) using UV LED light and are then hybridized with NanoString optical barcodes for ex situ counting on an nCounter Analysis system [13][14][15] .…”

“…This method utilizes UV-photocleavable oligonucleotides that are conjugated to primary antibodies [13][14][15] . After incubation with a multiplexed cocktail of primary antibodies, oligonucleotides are cleaved in regions of interest (ROIs) using UV LED light and are then hybridized with NanoString optical barcodes for ex situ counting on an nCounter Analysis system [13][14][15] . In this study, we sought to determine if DSP can be used to characterize expression of MHCII and other immune related proteins in tumor epithelial versus stromal compartments of patient-derived TNBC samples.…”

Changing Technologies of RNA Sequencing and Their Applications in Clinical Oncology

“…The GSP technology from NanoString Technologies, called GeoMx DSP, is commercially available and has already shown valuable applications in elucidating tumor microenvironments, immuno-oncology biomarker discovery, and optimizing immunotherapy by using targeted small gene panels. Ihle et al (45) characterized tumor microenvironment of lytic and blastic bone metastases in prostate cancer patients using DSP technology, and found a distinct set of immune cell populations and signaling pathways specifically present in lytic or blastic types of prostate cancer. The immune cells in blastic lesions were enriched for pSTAT3 and JAK-STAT pathway related genes while pAKT activity and PI3K-AKT pathway related genes were more active in lytic-type lesions.…”