Uptake of DNA by cancer cells without a transfection reagent

Yanping Kong,Ye Zhang,Xianbo Zhang,Yanfang Xue,Yongliang Zhao

doi:10.1186/s40659-017-0107-x

Abstract

BackgroundCancer cells exhibit elevated levels of glucose uptake and may obtain pre-formed, diet-derived fatty acids from the bloodstream to boost their rapid growth; they may also use nucleic acid from their microenvironment. The study of processing nucleic acid by cancer cells will help improve the understanding of the metabolism of cancer. DNA is commonly packaged into a viral or lipid particle to be transferred into cells; this process is called transfection in laboratory. Cancer cells are known for having gene mutations and the evolving ability of endocytosis. Their uptake of DNAs might be different from normal cells; they may take in DNAs directly from the environment. In this report, we studied the uptake of DNAs in cancer cells without a transfection reagent.MethodsA group of DNA fragments were prepared with PCR and labeled with isotope phosphorous-32 to test their uptake by Huh 7 (liver cancer) and THLE3 (normal liver cells) after incubation overnight by counting radioactivity of the cells’ genomic DNA. Multiple cell lines including breast cancer and lung cancer were tested with the same method. DNA molecules were also labeled with fluorescence to test the location in the cells using a kit of “label it fluorescence in situ hybridization (FISH)” from Mirus (USA).ResultsThe data demonstrated that hepatocellular carcinoma cells possess the ability to take in large DNA fragments directly without a transfection reagent whereas normal liver cells cannot. Huh7 and MDA-MB231 cells displayed a significantly higher Rhodamine density in the cytoplasmic phagosomes and this suggests that the mechanism of uptake of large DNA by cancer cells is likely endocytosis. The efficacy of uptake is related to the DNA’s size. Some cell lines of lung cancer and breast cancer also showed similar uptake of DNA.ConclusionsIn the present study, we have revealed the evidence that some cancer cells, but not nontumorigenic cells, can take DNA fragments directly from the environment without the aid of the transfecting reagent.

Highlights

Cancer cells exhibit elevated levels of glucose uptake and may obtain pre-formed, diet-derived fatty acids from the bloodstream to boost their rapid growth; they may use nucleic acid from their microenvironment
Cancer cells have been found to contain many gene mutations; they are malfunctioned in metabolism but they grow rapidly; their processing of nutrients and metabolism might be significantly different from normal cells
DNA fragments were taken by hepatocellular carcinoma (HCC) cells but not normal liver cells without transfection reagent To prove the hypothesis that cancer cells may have the ability to take DNA fragments directly without packaging with transfection reagent, DNA fragments with different lengths were tested in THLE3 and Huh7 cells without adding the transfection reagent

Summary

Introduction

Cancer cells exhibit elevated levels of glucose uptake and may obtain pre-formed, diet-derived fatty acids from the bloodstream to boost their rapid growth; they may use nucleic acid from their microenvironment. Cancer cells are known for having gene mutations and the evolving ability of endocytosis. Their uptake of DNAs might be different from normal cells; they may take in DNAs directly from the environment. Cancer cells have been found to contain many gene mutations; they are malfunctioned in metabolism but they grow rapidly; their processing of nutrients and metabolism might be significantly different from normal cells. Malignant cells have unique metabolic features with completely different gene profiles compared with normal cells. They could acquire the ability to take in DNA fragments from the environment and use them for their fast growing needs. We provide our evaluation on the uptake of DNA in some malignant cells

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Conclusion