Curcumin Counteracts the Proliferative Effect of Estradiol and Induces Apoptosis in Cervical Cancer Cells

Mol Cell Biochem. 2011 Jan;347(1-2):1-11. doi: 10.1007/s11010-010-0606-3. Epub 2010 Oct 13.

Abstract

Cervical cancer is the most common cancer in Indian females and is associated with infection with high-risk Human papilloma viruses (HPVs) which encode viral oncoprotein E6 and E7. Estradiol has been established as a risk factor for cervical cancer and has been shown to play a synergistic role with viral oncoproteins. Curcumin (Diferuloyl methane), a chemopreventive agent, is a natural compound extracted from Curcuma longa that allows suppression and retardation of carcinogenesis in many types of cancer and is currently being tested in various human clinical trials as it has been found to be well tolerated at higher doses with a relatively well established safety profile. The objective of this study was to test the effect of curcumin on HPV-positive and negative cervical cancer cell lines HeLa, SiHa, CaSki, and C33A pretreated with estradiol. It was found that HPV-positive cells pretreated with estradiol show reduced apoptosis as compared to curcumin by itself. However, curcumin was able to counteract the proliferative response of estradiol, and induce apoptosis. There was no difference in percentage apoptosis as compared to estradiol pretreatment in HPV-negative cell line C33A. Molecular studies showed elevation of Telomerase, viral oncoproteins E6 and E7, PCNA, p16, Cyclin D1 in HPV-positive cell lines on treatment with estradiol but after treatment with curcumin the level of E7, PCNA, and Cyclin D1 was reduced but the level of E6, Telomerase, and p16 was unaltered. Furthermore, estradiol-pretreated HPV-negative cell line C33A showed reduction in level of Telomerase, PCNA, p16, and activation of both p53 and p73 tumor suppressor proteins, thus, demonstrating the importance of E6 in estradiol-mediated protective effect.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects*
  • Blotting, Western
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Curcumin / pharmacology*
  • Cyclin D1 / metabolism
  • Cyclin-Dependent Kinase Inhibitor p16 / metabolism
  • DNA-Binding Proteins / metabolism
  • Estradiol / pharmacology
  • Female
  • Flow Cytometry
  • Humans
  • Models, Biological
  • Oncogene Proteins, Viral / metabolism
  • Papillomaviridae / physiology
  • Papillomavirus E7 Proteins / metabolism
  • Proliferating Cell Nuclear Antigen / metabolism
  • Signal Transduction / drug effects
  • Telomerase / metabolism
  • Tumor Suppressor Protein p53 / metabolism
  • Up-Regulation / drug effects
  • Uterine Cervical Neoplasms / enzymology
  • Uterine Cervical Neoplasms / pathology*
  • Uterine Cervical Neoplasms / virology

Substances

  • Antineoplastic Agents
  • Cyclin-Dependent Kinase Inhibitor p16
  • DNA-Binding Proteins
  • E6 protein, Human papillomavirus type 18
  • Oncogene Proteins, Viral
  • Papillomavirus E7 Proteins
  • Proliferating Cell Nuclear Antigen
  • Tumor Suppressor Protein p53
  • oncogene protein E7, Human papillomavirus type 16
  • Cyclin D1
  • Estradiol
  • Telomerase
  • Curcumin