Selection of microRNAs in extracellular vesicles for diagnosis of malignant pleural mesothelioma by in vitro analysis

Our plain-English summary of Selection of microRNAs in extracellular vesicles for diagnosis of malignant pleural mesothelioma by in vitro analysis, by T. Jotatsu, H. Izumi, Y. Morimoto, et al (Oncology Reports, 2020).

The study

• Authors: T. Jotatsu, H. Izumi, Y. Morimoto, K. Yatera
• Journal: Oncology Reports
• Published: 2020;44(5):2198-2210
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Malignant pleural mesothelioma (MPM) is a malignant tumor which is a challenge for diagnosis and is associated with a poor patient prognosis. Thus, early diagnostic interventions will improve the quality of life and life expectancy of these patients. Recently, cellular microRNAs (miRNAs) have been found to be involved in maintaining homeostasis, and abnormal miRNA expression has often been observed in various diseases including cancer. Extracellular vesicles (EVs) released by many cells contain proteins and nucleic acids. miRNAs are secreted from all cells via EVs and circulate throughout the body. In this study, culture media were passed sequentially through membrane filters 220‑50 nm in size, and EVs with diameters of 50 to 220 nm (EVcap50/220) were collected. miRNAs (EV50‑miRNAs) in EVcap50/220 were purified, and microarray analysis was performed. EV50‑miRNA expression profiles were compared between MPM cells and a normal pleural mesothelial cell line, and six EV50‑miRNAs were selected for further investigation. Of these, hsa‑miR‑193a‑5p and hsa‑miR‑551b‑5p demonstrated higher expression in MPM‑derived EVcap50/220. These miRNAs reduced the expression of several genes involved in cell‑cell interactions and cell‑matrix interactions in normal pleural mesothelial cells. Our data suggest that hsa‑miR‑193a‑5p and hsa‑miR‑551b‑5p in EVcap50/220 could be diagnostic markers for MPM.

In plain English

This was a laboratory (in vitro) study of cells grown in dishes. It did not study people or asbestos exposure. The authors compared six malignant pleural mesothelioma cell lines with one normal pleural mesothelial cell line (MeT-5A). Using membrane filters, they collected vesicles (tiny particles, 50 to 220 nm across) released by the cells, and measured the microRNAs (small RNA molecules) inside them. Of the vesicles between 20 and 220 nm, a 50-nm filter captured 80%. By microarray, they found 123 microRNAs in mesothelioma cell vesicles that were not detected in MeT-5A vesicles. The most abundant of these, hsa-miR-4728-5p, turned out to be highest inside the normal cells. By microarray, six candidates were not detected either inside the normal cells or in their vesicles. Two of them, hsa-miR-193a-5p and hsa-miR-551b-5p, were studied further. In normal cells made to produce these two, 288 and 146 gene messages respectively fell below 0.2 of control levels, and 122 were shared. Many were linked to cell adhesion. The authors suggested these microRNAs could be diagnostic markers for mesothelioma and said testing in clinical specimens is needed.

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: in vitro laboratory study of cultured cell lines
• Who was studied: Six malignant pleural mesothelioma cell lines (ACC-MESO1, ACC-MESO4, MSTO-211H, L324, N407, K921) and one normal pleural mesothelial cell line (MeT-5A). There were no human participants.
• Exposure: No asbestos or fiber exposure was studied. The study examined microRNAs in extracellular vesicles of 50 to 220 nm released by cultured cells.
• Main results:
  • Of the vesicles that passed a 220-nm filter, 64% were captured at 20 nm. Of those, 80% were captured by a 50-nm filter.
  • By microarray, 390 vesicle microRNAs were detected in MeT-5A cells and 502 in all six mesothelioma cell lines.
  • By microarray, 123 vesicle microRNAs were detected in the mesothelioma cell lines but not in MeT-5A cells.
  • By qPCR, levels of hsa-miR-4728-5p in vesicles from the mesothelioma cells were 5 to 17 times higher than in vesicles from MeT-5A cells.
  • Inside the cells, hsa-miR-4728-5p was highest in MeT-5A cells.
  • From the 123, the authors used microarray analysis to select microRNAs that were not found inside MeT-5A cells, and listed 6 candidates. hsa-miR-193a-5p and hsa-miR-551b-5p, which had the highest expression, were selected. These two were described as not often present in MeT-5A cells.
  • The authors made MeT-5A cells overexpress each microRNA and counted genes with control expression above 100 that fell to less than 0.2 of control levels. There were 288 such gene messages for hsa-miR-193a-5p and 146 for hsa-miR-551b-5p, and 122 were suppressed by both.
  • Many of the commonly suppressed genes were involved in cell-cell and cell-matrix adhesion.
• The authors' conclusion: The authors concluded that hsa-miR-193a-5p and hsa-miR-551b-5p in these vesicles could be diagnostic markers for malignant pleural mesothelioma.
• Limitations the authors state:
  • The study was done only in cell lines, and the authors stated that verification with clinical specimens is needed.
  • The expression ratios between cells did not correlate between the microarray and qPCR results.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Prognosis, Quality of Life, Life Expectancy, Mesothelial Cells.

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