Fluorescence-based codetection with protein markers reveals distinct cellular compartments for altered MicroRNA expression in solid tumors

TY - JOUR

T1 - Fluorescence-based codetection with protein markers reveals distinct cellular compartments for altered MicroRNA expression in solid tumors

AU - Sempere, Lorenzo F

AU - Preis, Meir

AU - Yezefski, Todd

AU - Ouyang, Haoxu

AU - Suriawinata, Arief A

AU - Silahtaroglu, Asli

AU - Conejo-Garcia, Jose R

AU - Kauppinen, Sakari

AU - Wells, Wendy

AU - Korc, Murray

PY - 2010/8/15

Y1 - 2010/8/15

N2 - Purpose: High-throughput profiling experiments have linked altered expression of microRNAs (miRNA) to different types of cancer. Tumor tissues are a heterogeneous mixture of not only cancer cells, but also supportive and reactive tumor microenvironment elements. To clarify the clinical significance of altered miRNA expression in solid tumors, we developed a sensitive fluorescence-based in situ hybridization (ISH) method to visualize miRNA accumulation within individual cells in formalin-fixed, paraffin-embedded tissue specimens. This ISH method was implemented to be compatible with routine clinical immunohistochemical (IHC) assays to enable the detection of miRNAs and protein markers in the same tissue section for colocalization and functional studies. Experimental Design: We used this combined ISH/IHC assay to study a subset of cancer-associated miRNAs, including miRNAs frequently detected at low (miR-34a and miR-126) and high (miR-21 and miR-155) levels, in a panel of breast, colorectal, lung, pancreas, and prostate carcinomas. Results: Despite the distinct histopathologic alterations of each particular cancer type, general trends emerged that pinpointed distinct source cells of altered miRNA expression. Although altered expressions of miR-21 and miR-34a were manifested within cancer cells, those of miR-126 and miR-155 were predominantly confined to endothelial cells and immune cells, respectively. These results suggest a heterogeneous participation of miRNAs in carcinogenesis by intrinsically affecting cancer cell biology or by modulating stromal, vascular, and immune responses. Conclusions: We described a rapid and sensitive multicolor ISH/IHC assay and showed that it could be broadly applied as an investigational tool to better understand the etiologic relevance of altered miRNA expression in cancer.

AB - Purpose: High-throughput profiling experiments have linked altered expression of microRNAs (miRNA) to different types of cancer. Tumor tissues are a heterogeneous mixture of not only cancer cells, but also supportive and reactive tumor microenvironment elements. To clarify the clinical significance of altered miRNA expression in solid tumors, we developed a sensitive fluorescence-based in situ hybridization (ISH) method to visualize miRNA accumulation within individual cells in formalin-fixed, paraffin-embedded tissue specimens. This ISH method was implemented to be compatible with routine clinical immunohistochemical (IHC) assays to enable the detection of miRNAs and protein markers in the same tissue section for colocalization and functional studies. Experimental Design: We used this combined ISH/IHC assay to study a subset of cancer-associated miRNAs, including miRNAs frequently detected at low (miR-34a and miR-126) and high (miR-21 and miR-155) levels, in a panel of breast, colorectal, lung, pancreas, and prostate carcinomas. Results: Despite the distinct histopathologic alterations of each particular cancer type, general trends emerged that pinpointed distinct source cells of altered miRNA expression. Although altered expressions of miR-21 and miR-34a were manifested within cancer cells, those of miR-126 and miR-155 were predominantly confined to endothelial cells and immune cells, respectively. These results suggest a heterogeneous participation of miRNAs in carcinogenesis by intrinsically affecting cancer cell biology or by modulating stromal, vascular, and immune responses. Conclusions: We described a rapid and sensitive multicolor ISH/IHC assay and showed that it could be broadly applied as an investigational tool to better understand the etiologic relevance of altered miRNA expression in cancer.

KW - Female

KW - Humans

KW - Image Interpretation, Computer-Assisted

KW - Immunohistochemistry

KW - In Situ Hybridization, Fluorescence

KW - Male

KW - MicroRNAs

KW - Neoplasms

KW - Paraffin Embedding

KW - Reproducibility of Results

KW - Tumor Markers, Biological

U2 - 10.1158/1078-0432.CCR-10-1152

DO - 10.1158/1078-0432.CCR-10-1152

M3 - Journal article

C2 - 20682703

SN - 1078-0432

VL - 16

SP - 4246

EP - 4255

JO - Clinical Cancer Research

JF - Clinical Cancer Research

IS - 16

ER -