title: Doxycycline Induces Apoptosis and Inhibits Proliferation and Invasion of Human Cervical Carcinoma Stem Cells.
abstract: BACKGROUND
  Cancer stem cells (CSCs) are proposed to be responsible for high recurrence rate in cervical carcinoma. Reagents that can suppress the proliferation and differentiation of CSCs would provide new opportunities to fight against tumor recurrence. Doxycycline has been reported as a potential anti-cancer compound. However, few studies investigated its inhibitory effect against cervical cancer stem cells.
  
  
  METHODS
  HeLa cells were cultured in cancer stem cell conditional media in a poly-hema-treated dish. In this non-adhesive culture system, HeLa cells were treated with cisplatin until some cells survived and formed spheroids, which were then collected and injected into the immunodeficient mice. Cisplatin was administered every three days for five times. The tumor xenografts with CSC enrichment were cultured in cancer stem cell specific medium again to form tumorsphere, which we called HeLa-CSCs. Expression of cancer stem cell markers in HeLa-CSCs was measured by flow cytometry and qPCR. HeLa-CSCs were then treated with doxycycline. Proliferation and differentiation rates were determined by the size of spheres formed in vitro and tumor formed in vivo.
  
  
  RESULTS
  We developed a new strategy to selectively enrich CSCs from human cervical carcinoma cell line HeLa, and these HeLa-CSCs are CD133+/CD49f+ cell populations with significantly enhanced expression of stem cell markers. When these HeLa-CSCs were treated with doxycycline, the colony formation, proliferation, migration and invasion, and differentiation were all suppressed. Meanwhile, stem cell markers SOX-2, OCT-4, NANOG, NOTCH and BMI-1 decreased in doxycycline treated cells, so as the surface markers CD133 and CD49f. Furthermore, proliferation markers Ki67 and PCNA were also decreased by doxycycline treatment in the in vivo xenograft mouse model.
  
  
  CONCLUSIONS
  Cancer stem cells are enriched from sphere-forming and chemoresistant HeLa-derived tumor xenografts in immunodeficient mice. Doxycycline inhibits proliferation, invasion, and differentiation, and also induces apoptosis of these HeLa-CSCs in vitro and in vivo.
authors.affiliation: Department of Gynecology & Obstetrics, People Hospital of Pudong New Area, Shanghai, 20299, China.
authors.forename: Binlie
authors.initials: B
authors.lastname: Yang
authors.affiliation: Department of Gynecology & Obstetrics, People Hospital of Pudong New Area, Shanghai, 20299, China.
authors.forename: Yuping
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of Gynecology & Obstetrics, People Hospital of Pudong New Area, Shanghai, 20299, China.
authors.forename: Ai
authors.initials: A
authors.lastname: Zhang
authors.affiliation: Department of Gynecology & Obstetrics, People Hospital of Pudong New Area, Shanghai, 20299, China.
authors.forename: Aizhi
authors.initials: A
authors.lastname: Zhou
authors.affiliation: Department of Gynecology & Obstetrics, People Hospital of Pudong New Area, Shanghai, 20299, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Gynecology & Obstetrics, People Hospital of Pudong New Area, Shanghai, 20299, China.
authors.forename: Lanrong
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Gynecology & Obstetrics, People Hospital of Pudong New Area, Shanghai, 20299, China.
authors.forename: Limin
authors.initials: L
authors.lastname: Gao
authors.affiliation: Department of Gynecology & Obstetrics, People Hospital of Pudong New Area, Shanghai, 20299, China.
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Zang
authors.affiliation: Department of Gynecology & Obstetrics, People Hospital of Pudong New Area, Shanghai, 20299, China.
authors.forename: Xiuhua
authors.initials: X
authors.lastname: Tang
authors.affiliation: Department of Gynecology & Obstetrics, People Hospital of Pudong New Area, Shanghai, 20299, China.
authors.forename: Liyan
authors.initials: L
authors.lastname: Sun
mesh_terms: D000818:Animals; D017209:Apoptosis; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002945:Cisplatin / Q000008:administration & dosage* / Q000494:pharmacology; D017077:Culture Media, Conditioned / Q000737:chemistry; D004318:Doxycycline / Q000008:administration & dosage* / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D009361:Neoplasm Invasiveness; D014411:Neoplastic Stem Cells / Q000187:drug effects*; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D023041:Xenograft Model Antitumor Assays
chemical_list: D017077:Culture Media, Conditioned; D004318:Doxycycline; D002945:Cisplatin