title: Effects of siRNA targeting BMPR-II on the biological activities of human liver cancer cells and its mechanism.
abstract: BACKGROUND
  Bone morphogenetic protein receptor II (BMPR-II) plays an important role in tumor's invasion and proliferation. In this study, we observed the effects of small interfering RNA (siRNA) targeting bone morphogenetic protein receptor II (BMPR-II) on the biological activities of human liver cells and explore its mechanism.
  
  
  METHODS
  The molecular sequences of three siRNA targeting BMPR-IIwere designed and synthesized. In this study, there were 6 groups including group I (normal control), group II (blank control), group III (negative control) and group IV-VI (BMPR-II-siRNA-a, siRNA-b and siRNA-c-transfected cells, respectively). The levels of mRNA and protein of BMPR-II were determined to select the best sequence for BMPR-II silence. After liver cancer cells were transfected with the best sequence, proliferation and invasion of transfected cells were assessed, and apoptosis and cell cycle were detected. The expressions of mitogen-activated protein kinases (MAPKs) signal pathway-related VEGF-C protein were observed after BMPR-II silence and BMPR-II silence combined with inhibiting MAPKs signal pathway, respectively.
  
  
  RESULTS
  RT-PCR and Western blot indicated that BMPR-II expression was the highest in HepG2 among the three liver cancer lines (P < 0.01) and the lowest in group IV among the six groups (P < 0.01). MTT assay and transwell assay revealed that the numbers of cell growth and cell transmembrane were significantly lower in group IV than in control groups 48 h after cells were transfected (P < 0.05). Flow cytometer showed that apoptosis was the highest and cells were significantly blocked in S phase 48 h after cells were transfected in group IV (P < 0.01). Western blot indicated that the protein levels of p-P38 (P < 0.01) and vascular endothelial growth factor-C (VEGF-C) (P < 0.01) were significantly decreased after BMPR-II silence. The protein level of VEGF-C was significantly decreased in PD98059 + siRNA-BMPR-II-a and SB203580 + siRNA-BMPR-II-a groups (P < 0.01), especially in SB203580 + siRNA-BMPR-II-a group (P < 0.01).
  
  
  CONCLUSIONS
  siRNA targeting BMPR-IIcan markedly inhibit HepG2 proliferation and invasion, promote apoptosis and block HepG2 in S phase. Its mechanism may be that BMPR-II silence down-regulates VEGF-C expression through MAPK/P38 and MAPK/ERK1/2 pathways, especially MAPK/P38. This study provides a new targeted therapy for liver cancer.
authors.affiliation: Department of Oncology, the Second Affiliated Hospital, Nanchang University, Nanchang 330006, China ; Key Laboratory of Molecular Medicine Jiangxi Province, Nanchang 330006, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zeng
authors.affiliation: Department of Oncology, the Second Affiliated Hospital, Nanchang University, Nanchang 330006, China ; Key Laboratory of Molecular Medicine Jiangxi Province, Nanchang 330006, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Cai
authors.affiliation: Department of Pathology, the Second Affiliated Hospital, Nanchang University, Nanchang 330006, China ; Key Laboratory of Molecular Medicine Jiangxi Province, Nanchang 330006, China.
authors.forename: Jia-Na
authors.initials: JN
authors.lastname: Zhang
authors.affiliation: Department of Oncology, the Second Affiliated Hospital, Nanchang University, Nanchang 330006, China.
authors.forename: Feng-Ming
authors.initials: FM
authors.lastname: Yi
authors.affiliation: Department of Oncology, the Second Affiliated Hospital, Nanchang University, Nanchang 330006, China.
authors.forename: Wei-Min
authors.initials: WM
authors.lastname: Jiang
authors.affiliation: Department of Oncology, the Second Affiliated Hospital, Nanchang University, Nanchang 330006, China ; One number, Minde Road, Nanchang City, Jiangxi Province, China.
authors.forename: Jian-Bing
authors.initials: JB
authors.lastname: Wu
keywords: Bone morphogenetic protein receptor II; Liver cancer; Mitogen-activated protein kinases; Small interfering RNA; Vascular endothelial growth factor-C