Identification of a differential expression of two cDNAs between malignant mesothelioma and normal mesothelial cells using the RNA fingerprint method

Our plain-English summary of Identification of a differential expression of two cDNAs between malignant mesothelioma and normal mesothelial cells using the RNA fingerprint method, by S. Frank, B.U. von Specht, W. Sendt, et al (Tumour Biology, 1998).

The study

• Authors: S. Frank, B.U. von Specht, W. Sendt, E.H. Farthmann, T. Hirsch
• Journal: Tumour Biology
• Published: 1998;19(3):153-9
• Read it: PubMed · Publisher

Abstract

The RNA fingerprint method was used to identify mRNAs that were differentially expressed during the development of human mesothelial cell cancer. We report the isolation of two differentially expressed clones. One clone was expressed in the metastatic mesothelioma cell line M1A and in the malignant mesothelioma cell line M1 and downregulated in normal mesothelial cells. M1 and M1A were derived from a primary and metastatic tumor of the same patient. The other clone was only expressed in normal mesothelial cells. The different expression pattern was confirmed by Northern blot analysis. One clone had a striking sequence homology to the soares pregnant uterus NbHPU homo sapiens cDNA clone. The other clone contained a high sequence homology to the human mRNA for ORF. The biological function of the corresponding genes is unknown. The specificity of expression of the two sequence tags was further examined on different cancer cell lines and normal tissues.

In plain English

This laboratory study compared gene activity in normal human peritoneal mesothelial cells with two mesothelioma cell lines from one patient. M1 came from a pleural biopsy and M1A from a lung metastasis of that tumor. Using a technique called RNA fingerprinting, the authors found two pieces of genetic material (clones) that differed between the cells. They confirmed the differences with Northern blots, including normal cells from five other patients. Clone 3.2 was strongly expressed in M1 and M1A and only weakly in the normal cells. Clone 4.2 was expressed only in the normal cells. The biological function of the matching genes was unknown. Clone 3.2 also appeared in some normal tissues, such as small intestine and colon, and in some other cancer cell lines, so the authors concluded it could not be a specific marker. Clone 4.2 was found only in normal mesothelial cells and spleen tissue, and the authors considered it of interest as a possible tumor suppressor gene. The study did not examine asbestos exposure.

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 study of gene expression in cultured human cells (RNA fingerprinting, confirmed by Northern blot analysis and sequencing)
• Who was studied: Normal human peritoneal mesothelial cells grown from omental tissue of patients having elective abdominal surgery. Mesothelioma cell lines M1 (from a human pleural biopsy) and M1A (a lung metastasis from the same patient), purchased from the DKFZ, Heidelberg, Germany. The clones were also tested on other cancer cell lines, 16 normal human tissues and 8 non-human species. Dates and patient details are not given.
• Exposure: No asbestos exposure was studied. Asbestos is mentioned only as background in the introduction; the study compared gene expression between malignant and normal mesothelial cells.
• Main results:
  • Clone 3.2 (289 bp) was strongly expressed in mesothelioma cell lines M1A and M1 and only weakly in normal human peritoneal mesothelial cells.
  • Clone 4.2 (298 bp) was expressed only in normal human peritoneal mesothelial cells, not in the mesothelioma cell lines.
  • Because normal mesothelial cells could not be obtained from the patient who supplied M1 and M1A, the expression pattern was confirmed using normal mesothelial cells from five different patients.
  • In database searches, clone 3.2 matched the soares pregnant uterus NbHPU homo sapiens cDNA clone over 245 bp. Clone 4.2 matched the human mRNA for ORF over 243 bp. The biological function of the corresponding genes is unknown.
  • Clone 3.2 was expressed in some normal human tissues, such as small intestine and colon, and in some cancer cell lines. It was not expressed in the cancer cell lines MATCAL-2, CAPAN-1, U-937, REH and A-431.
  • Clone 4.2 was expressed only in human peritoneal mesothelial cells and human spleen tissue, and in none of the cancer cell lines tested.
• The authors' conclusion: The authors concluded that clone 3.2, being present in various normal tissues and some cancer cell lines, could not be a specific marker of mesothelial cancer progression. Clone 4.2, found only in normal mesothelial and spleen cells, could be of interest as a candidate tumor suppressor gene. They also concluded that the fingerprint method was more reproducible than standard differential display.
• Limitations the authors state:
  • Normal mesothelial cells could not be obtained from the same patient as the mesothelioma cell lines.
  • Despite testing over 40 primer combinations, only a few differences were found. The authors said the method may not be sensitive enough to detect differences between closely related cell types.
  • Further work, especially cloning the full-length cDNAs, is needed to establish the function and specificity of the sequence tags as potential markers.

Topics

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

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Mesothelial Cells, Mesothelioma.

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