Single-cell Spatial Proteomic Revelations on the Multiparametric MRI Heterogeneity of Clinically Significant Prostate Cancer

Abstract

Purpose: Multiparametric MRI (mpMRI) has become an indispensable radiographic tool in diagnosing prostate cancer. However, mpMRI fails to visualize approximately 15% of clinically significant prostate cancer (csPCa). The molecular, cellular, and spatial underpinnings of such radiographic heterogeneity in csPCa are unclear. Experimental Design: We examined tumor tissues from clinically matched patients with mpMRI-invisible and mpMRI-visible csPCa who underwent radical prostatectomy. Multiplex immunofluorescence single-cell spatial imaging and gene expression profiling were performed. Artificial intelligence–based analytic algorithms were developed to examine the tumor ecosystem and integrate with corresponding transcriptomics. Results: More complex and compact epithelial tumor architectures were found in mpMRI-visible than in mpMRI-invisible prostate cancer tumors. In contrast, similar stromal patterns were detected between mpMRI-invisible prostate cancer and normal prostate tissues. Furthermore, quantification of immune cell composition and tumor-immune interactions demonstrated a lack of immune cell infiltration in the malignant but not in the adjacent nonmalignant tissue compartments, irrespective of mpMRI visibility. No significant difference in immune profiles was detected between mpMRI-visible and mpMRI-invisible prostate cancer within our patient cohort, whereas expression profiling identified a 24-gene stromal signature enriched in mpMRI-invisible prostate cancer. Prostate cancer with strong stromal signature exhibited a favorable survival outcome within The Cancer Genome Atlas prostate cancer cohort. Notably, five recurrences in the 8 mpMRI-visible patients with csPCa and no recurrence in the 8 clinically matched patients with mpMRI-invisible csPCa occurred during the 5-year follow-up post-prostatectomy. Conclusions: Our study identified distinct molecular, cellular, and structural characteristics associated with mpMRI-visible csPCa, whereas mpMRI-invisible tumors were similar to normal prostate tissue, likely contributing to mpMRI invisibility.

Mapping Spatiotemporal Heterogeneity in Tumour Progression by Integrating High-Throughput Imaging and Omics Analysis

“…Differences between mp-MRI (multi-parametric MRI)-invisible and mp-MRI-visible prostate cancer tumours were visualized at a single-cell resolution through the annotated pipeline of segmentation, cell typing, modelling of tumour architecture and spatial interactions, and the employment of softwaregenerated masks. The visible mp-MRI tumours did not show specific boundaries between the stromal and glandular components, but invisible ones had a rounded glandular structure and had less closely spaced glands interspersed with stroma, thus bearing more similarity to normal prostate tissue 83 . Similarly, spatial transcriptomics on patient samples with adeno-carcinoma post radical prostatectomy revealed tissue-wide gene expression heterogeneity.…”

“…Further, analysis of 176 primary and metastatic prostate tumours unravelled that both the phenotypes (adenocarcinoma, SCNC) could co-exist in a patient in distinct metastatic lesions, thereby indicating lineage plasticity 82 . In another prostate cancer study, tissue samples from the patients who underwent radical prostatectomy were analysed using an artificial intelligence (AI) based method 83 . Differences between mp-MRI (multi-parametric MRI)-invisible and mp-MRI-visible prostate cancer tumours were visualized at a single-cell resolution through the annotated pipeline of segmentation, cell typing, modelling of tumour architecture and spatial interactions, and the employment of softwaregenerated masks.…”

Prostate cancer multiparametric magnetic resonance imaging visibility is a tumor-intrinsic phenomena

“…Within International Society of Urological Pathology (ISUP) Grade Group 2, mpMRI visibility is associated with increased genomic instability, presence of intraductal carcinoma and/or cribriform architecture (IDC/CA) histology and hypoxia, a constellation of features termed nimbosus [ 3 , 7 ]. Given the role of cellular density and perfusion in mpMRI, differences in stromal organization in non-malignant tissue [ 4 ] are hypothesized to affect water diffusion and thus mediate tumor microenvironmental influence on mpMRI visibility.…”

Harnessing the Utility of Ex Vivo Patient Prostate Tissue Slice Cultures

“…Despite the challenges, TS cultures provide spatial examination of inter and intra-patient heterogeneity not possible by other methods. The rapid advancement and increased resolution of spatial transcriptomic methods ( 32 , 33 ) offers the ability to compare transcriptomic differences (RNAseq) between areas of the tissue and between patients. Co-detection by indexing (CODEX) tissue imaging with DNA-barcoded antibodies has the potential to examine up to 60 markers in one sample ( 34 ), which would greatly expand the data available from a TS experiment.…”