microRNAs in Cancer Chemoprevention: Method to Isolate Them from Fresh Tissues

Our plain-English summary of microRNAs in Cancer Chemoprevention: Method to Isolate Them from Fresh Tissues, by F. Ganci, G. Blandino (Methods in Molecular Biology, 2016).

The study

• Authors: F. Ganci, G. Blandino
• Journal: Methods in Molecular Biology
• Published: 2016;1379:21-9
• Read it: PubMed · Publisher

Abstract

microRNAs are 22-nucleotide-long double-strand small RNAs, able to modulate gene expression at posttranscriptional level, degrading mRNA and/or impairing translation. They have been shown to regulate mRNA and protein abundance and to participate in many regulatory circuits controlling developmental timing, cell proliferation and differentiation, apoptosis and stress response. Notably, microRNA activity has been correlated to the pathogenesis of cancer; they are aberrantly expressed in solid and hematological tumors, suggesting that they could function as oncogenes or tumor suppressors. The emerging role of miRNAs in the carcinogenesis and tumor progression has provided opportunities for their clinical application in the capacity of cancer detection, diagnosis, and prognosis prediction. Here, we describe the experimental protocol used to isolate microRNAs from human tissues coming from head and neck, mesothelioma, and thymoma tumors in order to perform microarray and RT-qPCR experiments.

In plain English

This book chapter is a laboratory methods protocol, not a study of patients or of asbestos exposure. The authors described how their laboratory isolated total RNA, including microRNAs (small molecules that help control which genes are active), from fresh frozen tumor tissue from head and neck cancers, mesothelioma and thymoma. The RNA was intended for microRNA analyses by RT-qPCR and/or microarray. In the protocol, tumor and normal control tissue was placed in a stabilizing solution after surgery, kept overnight at 4 °C, then frozen at minus 80 °C. RNA was extracted with a commercial kit, with modifications the authors described, and checked for quantity, purity and integrity. The authors reported that, in their experience, microRNA results from degraded RNA samples were comparable with results from intact RNA. They gave no figures for this. They also noted that good-quality RNA allows gene and microRNA profiles to be measured from the same sample. The chapter does not say how many patients or samples were involved and contains no information on asbestos.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory methods protocol (book chapter describing an RNA extraction procedure)
• Who was studied: Fresh frozen human tumor tissue and normal control tissue from head and neck, mesothelioma and thymoma tumors removed by surgery; number of samples, location and dates not given
• Main results:
  • In the authors' experience, microRNA expression results from samples with degraded RNA were comparable with results from intact RNA (no numbers given)
  • The extraction method purifies all RNA molecules longer than 18 nucleotides
  • RNA Integrity Number values over 7 are described as typically good enough for transcriptome analysis on Affymetrix and Agilent platforms
• The authors' conclusion: The authors stated that a robust RNA isolation method is essential for reproducible results, and that good-quality total RNA allows both mRNA and microRNA profiles to be measured from the same sample
• Limitations the authors state:
  • The authors noted that estimating microRNA abundance with the Bioanalyzer may only be accurate when overall RNA integrity is very high

Topics

Medical terms in this study, explained in our Lexicon: Apoptosis, Carcinogenesis, Prognosis, Mesothelioma.

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