title: Gene delivery of cyclin-dependent kinase inhibitors p21Waf1 and p27Kip1 suppresses proliferation of MCF-7 breast cancer cells in vitro.
abstract: BACKGROUND
  Because tumorigenesis depends on a variety of oncogenes, symphyseal study of combined genes may lead to more significant knowledge about tumorigenesis and progression. Combined deficiency of p21 and p27 proteins in mice is linked to more aggressive spontaneous tumorigenesis. We investigated the effect of the transfected p21 (Waf1) -p27 (Kip1) gene on centrosome duplication, cell proliferation, and apoptosis of MCF-7, a breast cancer cell line.
  
  
  METHODS
  The pIRES-p21 (Waf1) , pIRES-p27 (Kip1) , and pIRES-p21 (Waf1) -p27 (Kip1) genes were transfected into MCF-7 cells by lipofection. The effect on proliferation was evaluated by MTT assay and clone-formation assay. Cell cycle and apoptosis were analyzed by flow cytometry. Apoptosis was tested by flow cytometry and TUNEL assay. Centrosome duplication was detected by use of indirect immunofluorescence microscopy.
  
  
  RESULTS
  The results showed that the pIRES-p21 (Waf1) , pIRES-p27 (Kip1) , and pIRES-p21 (Waf1) -p27 (Kip1) significantly inhibited proliferation of MCF-7 cells, followed by accumulation of MCF-7 cells in cycle G1, induced apoptosis, and a decrease in the proportion of MCF-7 cells which contained abnormal centrosomes. Compared with p21 (Waf1) or p27 (Kip1) alone, combination of p21 (Waf1) and p27 (Kip1) had a much more significant effect (P < 0.05).
  
  
  CONCLUSIONS
  Altogether, these results indicate that the p21 (Waf1) -p27 (Kip1) gene combination has a more obvious antitumor effect than p21 (Waf1) or p27 (Kip1) alone. This study provides preclinical evidence that combination of p21 (Waf1) and p27 (Kip1) could be a novel and promising therapeutic approach to treatment of breast cancer with suppressed p21 (Waf1) and p27 (Kip1) expression.
authors: Breast Surgery, The Affiliated Hospital of Medical College, Qingdao University, Qingdao, 266003, Shandong, China.
authors: Dandan
authors: D
authors: Jiang
authors: Xingang
authors: X
authors: Wang
authors: Xiangping
authors: X
authors: Liu
authors: Funian
authors: F
authors: Li
mesh_terms: D017209:Apoptosis / Q000235:genetics; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology*; D002453:Cell Cycle / Q000235:genetics; D049109:Cell Proliferation / Q000235:genetics; D018385:Centrosome / Q000502:physiology; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics* / Q000378:metabolism; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000235:genetics* / Q000378:metabolism; D005260:Female; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods; D006801:Humans; D061986:MCF-7 Cells; D014162:Transfection
chemical_list: C493956:CDKN1A protein, human; C436291:CDKN1B protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D050760:Cyclin-Dependent Kinase Inhibitor p27