title: The role of the globular heads of the C1q receptor in HPV-16 E2-induced human cervical squamous carcinoma cell apoptosis via a mitochondria-dependent pathway.
abstract: BACKGROUND
  Human papillomavirus type-16 (HPV-16) E2 protein acts as a transcriptional modulator and plays a key role in regulating many biological responses. The purpose of this study was to investigate the relationship between HPV-16 E2, the receptor for the globular heads of human C1q (gC1qR) gene expression, mitochondrial dysfunction and apoptosis regulation in human cervical squamous carcinoma cells (C33a and SiHa).
  
  
  METHODS
  HPV-16 E2 and gC1qR expression was examined using real-time PCR and western blot analysis. Apoptosis in C33a and SiHa cells was assessed by flow cytometry. Mitochondrial function was detected via ROS generation, the amount of cytosolic Ca2+, and changes in the mitochondrial membrane potential (Δψm).
  
  
  RESULTS
  The expression of the HPV-16 E2 and gC1qR gene significantly decreased in human cervical squamous carcinoma samples relative to the non-cancerous cervix samples. C33a and SiHa cells that were transfected with a vector encoding HPV-16 E2 displayed significantly increased gC1qR gene expression and mitochondrial dysfunction as well as an up-regulation of cellular apoptosis, which was abrogated by the addition of gC1qR small-interfering RNA (siRNA).
  
  
  CONCLUSIONS
  These data support a mechanism whereby gC1qR plays an important role in HPV-16 E2-induced human cervical squamous carcinoma cell apoptosis via a mitochondria-dependent pathway.
authors.forename: Zheng-lin
authors.initials: ZL
authors.lastname: Chen
authors.forename: Ya-juan
authors.initials: YJ
authors.lastname: Su
authors.forename: Hui-lin
authors.initials: HL
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Reproductive Medicine, Department of Clinical Laboratory, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing 210004, China. njgpq@163.com.
authors.forename: Ping-qing
authors.initials: PQ
authors.lastname: Gu
authors.forename: Ling-juan
authors.initials: LJ
authors.lastname: Gao
mesh_terms: D000328:Adult; D017209:Apoptosis; D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000821:virology; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005260:Female; D052162:Human papillomavirus 16 / Q000502:physiology*; D006801:Humans; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D008928:Mitochondria / Q000378:metabolism / Q000473:pathology*; D009856:Oncogene Proteins, Viral / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011951:Receptors, Complement / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013329:Structure-Activity Relationship; D002583:Uterine Cervical Neoplasms / Q000473:pathology* / Q000821:virology; D055815:Young Adult
chemical_list: D004268:DNA-Binding Proteins; C054855:E2 protein, Human papillomavirus type 16; D008562:Membrane Glycoproteins; D009856:Oncogene Proteins, Viral; D011951:Receptors, Complement; C032402:complement 1q receptor