A method for recovery of high-molecular-weight DNA suitable for field-inversion gel electrophoresis from frozen tumor cells

Our plain-English summary of A method for recovery of high-molecular-weight DNA suitable for field-inversion gel electrophoresis from frozen tumor cells, by J.E. Reynolds, S.R. Diehl (Cancer Genetics and Cytogenetics, 1993).

The study

• Authors: J.E. Reynolds, S.R. Diehl
• Journal: Cancer Genetics and Cytogenetics
• Published: 1993;65(1):68-70
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

We describe a simple method for isolation of high-molecular-weight (high-mol-wt, > 800 kilobases) DNA from tumor cell lines frozen without dimethylsulfoxide (DMSO) or other protective agents. This method should be applicable to most frozen tissues and useful for molecular genetic studies such as field-inversion gel electrophoresis (FIGE), or cloning procedures that require access to intact, high-mol-wt DNA.

In plain English

This short laboratory report described a method for extracting very long, intact DNA from tumor cells that had been frozen without dimethylsulfoxide (DMSO) or other protective agents. The authors noted that such freezing breaks cells apart, so frozen tissues had usually been considered unsuitable for techniques that need very long DNA. The authors used a mesothelioma tumor cell line, ST88-58. Its cells were pelleted and frozen at -70°C for several months. Portions of the frozen pellet were mixed with warm agarose and saline, formed into plugs, and treated to release the DNA. The DNA was cut with enzymes and separated by field-inversion gel electrophoresis. It was then compared with DNA from a lymphoblastoid control cell line that had not been frozen. The same procedure was also used on a frozen endometrial stromal sarcoma cell line, ST88-42. Large DNA fragments of the expected size, including a 290-kilobase fragment, were seen in both the control and the frozen samples. No sign of DNA breakdown was seen in the frozen samples. The study did not examine asbestos exposure. The authors concluded that the method probably can be readily adapted for many other kinds of frozen tumor tissue.

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 report (short communication) describing a DNA extraction technique
• Who was studied: a mesothelioma tumor cell line (ST88-58) and a frozen endometrial stromal sarcoma cell line (ST88-42), compared with lymphoblastoid control cells that had not been frozen; no human subjects
• Exposure: no asbestos or other environmental exposure was studied; the condition tested was freezing cell pellets at -70°C, without DMSO, glycerol or other preservatives, for several months before DNA extraction
• Main results:
  • Large DNA fragments of the appropriate size were observed both in the unfrozen control samples and in the frozen tumor cell line samples prepared by the new method
  • No evidence of DNA degradation was seen in the frozen mesothelioma cell line samples (Figure 1)
  • A 290-kb SacII DNA fragment was detected in DNA from the frozen endometrial stromal sarcoma cell line ST88-42
  • The stronger signal in one control lane was attributed by the authors to more DNA being loaded, not to greater degradation of the frozen samples
• The authors' conclusion: The authors concluded that the method probably can be readily optimized for many other kinds of frozen tumor tissues

Topics

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

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