title: Cholesterol depletion by methyl-β-cyclodextrin augments tamoxifen induced cell death by enhancing its uptake in melanoma.
abstract: BACKGROUND
  Despite modern advances in treatment, skin cancer is still one of the most common causes of death in the western countries. Chemotherapy plays an important role in melanoma management. Tamoxifen has been used either alone or in- combination with other chemotherapeutic agents to treat melanoma. However, response rate of tamoxifen as a single agent has been comparatively low. In the present study, we investigated whether treatment with methyl-β-cyclodextrin (MCD), a cholesterol depleting agent, increases the efficacy of tamoxifen in melanoma cells.
  
  
  METHODS
  This was a two-part study that incorporated in vitro effects of tamoxifen and MCD combination by analyzing cell survival, apoptosis and cell cycle analysis and in vivo antitumor efficacy on tumor isografts in C57BL/6J mice.
  
  
  RESULTS
  MCD potentiated tamoxifen induced anticancer effects by causing cell cycle arrest and induction of apoptosis. Sensitization to tamoxifen was associated with down regulation of antiapoptotic protein Bcl-2, up-regulation of proapoptotic protein Bax, reduced caveolin-1 (Cav-1) and decreased pAkt/pERK levels. Co-administration of tamoxifen and MCD caused significant reduction in tumor volume and tumor weight in mice due to enhancement of drug uptake in the tumor. Supplementation with cholesterol abrogated combined effect of tamoxifen and MCD.
  
  
  CONCLUSIONS
  Our results emphasize a potential synergistic effect of tamoxifen with MCD, and therefore, may provide a unique therapeutic window for improvement in melanoma treatment.
authors.forename: Naoshad
authors.initials: N
authors.lastname: Mohammad
authors.forename: Parmanand
authors.initials: P
authors.lastname: Malvi
authors.forename: Avtar Singh
authors.initials: AS
authors.lastname: Meena
authors.forename: Shivendra Vikram
authors.initials: SV
authors.lastname: Singh
authors.forename: Balkrishna
authors.initials: B
authors.lastname: Chaube
authors.forename: Garikapati
authors.initials: G
authors.lastname: Vannuruswamy
authors.forename: Mahesh J
authors.initials: MJ
authors.lastname: Kulkarni
authors.affiliation: National Centre for Cell Science, NCCS Complex, Ganeshkhind, Pune 411007, India. manojkbhat@nccs.res.in.
authors.forename: Manoj Kumar
authors.initials: MK
authors.lastname: Bhat
mesh_terms: D000818:Animals; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology*; D000971:Antineoplastic Combined Chemotherapy Protocols; D017209:Apoptosis; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002784:Cholesterol / Q000378:metabolism*; D004357:Drug Synergism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008545:Melanoma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D009368:Neoplasm Transplantation; D013629:Tamoxifen / Q000008:administration & dosage / Q000494:pharmacology*; D023041:Xenograft Model Antitumor Assays; D047392:beta-Cyclodextrins / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D013629:Tamoxifen; D002784:Cholesterol