title: Uptake of DNA by cancer cells without a transfection reagent.
abstract: BACKGROUND
  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 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.
  
  
  METHODS
  A 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).
  
  
  RESULTS
  The 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.
  
  
  CONCLUSIONS
  In 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.
authors.affiliation: Department of Endocrinology, Dartmouth-Hitchcock Manchester, 100 Hitchcock Way, Manchester, New Hampshire, 03104, USA. yanping.kong@hitchcock.org.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Kong
authors.affiliation: Department of Surgery/Oncology, First Hospital of Shijiazhuang, 36 Fanxi Road, Shijiazhuang, 050011, Hebei, China.
authors.forename: Xianbo
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Laboratory of Disease Genomics and Individualized Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, 1 Beichen West Road, Beijing, 10029, China.
authors.forename: Yongliang
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Pharmacology, Hebei Medical University, 361 Zhongshan E Rd, Shijiazhuang, 050056, Hebei, China.
authors.forename: Yanfang
authors.initials: Y
authors.lastname: Xue
authors.affiliation: National Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Dongdan Santiao, Beijing, 100005, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics / Q000473:pathology; D002460:Cell Line; D045744:Cell Line, Tumor; D004247:DNA / Q000378:metabolism*; D053938:DNA Fragmentation; D004705:Endocytosis / Q000235:genetics; D005260:Female; D023281:Genomics; D022781:Hepatocytes / Q000378:metabolism; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008055:Lipids / Q000494:pharmacology; D008113:Liver Neoplasms / Q000235:genetics / Q000473:pathology; D008175:Lung Neoplasms / Q000235:genetics / Q000473:pathology; D009369:Neoplasms / Q000235:genetics* / Q000473:pathology; D016133:Polymerase Chain Reaction; D014162:Transfection; D000509:alpha-Fetoproteins / Q000378:metabolism
chemical_list: C411955:FuGene; D008055:Lipids; D000509:alpha-Fetoproteins; D004247:DNA
keywords: Cancer cells; DNA uptake; Endocytosis