title: Simvastatin increases the antineoplastic actions of paclitaxel carried in lipid nanoemulsions in melanoma-bearing mice.
abstract: OBJECTIVE
  Lipid nanoemulsions (LDEs) that bind to low-density lipoprotein (LDL) receptors used as carriers of paclitaxel (PTX) can decrease toxicity and increase PTX antitumoral action. The administration of simvastatin (Simva), which lowers LDL-cholesterol, was tested as an adjuvant to commercial PTX and to PTX associated with LDE (LDE-PTX).
  
  
  METHODS
  B16F10 melanoma-bearing mice were treated with saline solution or LDE (controls), Simva, PTX, PTX and Simva, LDE-PTX, and LDE-PTX and Simva: PTX dose 17.5 μmol/kg (three intraperitoneal injections, 3 alternate days): Simva 50 mg/kg/day by gavage, 9 consecutive days.
  
  
  RESULTS
  Compared with saline controls, 95% tumor-growth inhibition was achieved by LDE-PTX and Simva, 61% by LDE-PTX, 44% by PTX and Simva, and 43% by PTX. Simva alone had no effect. Metastasis developed in only 37% of the LDE-PTX and Simva, 60% in LDE-PTX, and 90% in PTX and Simva groups. Survival rates were higher in LDE-PTX and Simva and in LDE-PTX groups. The LDE-PTX and Simva group presented tumors with reduced cellular density and increased collagen fibers I and III. Tumors from all groups showed reduction in immunohistochemical expression of ICAM, MCP-1, and MMP-9; LDE-PTX and Simva presented the lowest MMP-9 expression. Expression of p21 was increased in the Simva, LDE-PTX, and LDE-PTX and Simva groups. In the Simva and LDE-PTX and Simva groups, expression of cyclin D1, a proliferation and survival promoter of tumor cells, was decreased. Therapy with LDE-PTX and Simva showed negligible toxicity compared with PTX and Simva, which resulted in weight loss and myelosuppression.
  
  
  CONCLUSIONS
  Simva increased the antitumor activity of PTX carried in LDE but not of PTX commercial presentation, possibly because statins increase the expression of LDL receptors that internalize LDE-PTX.
authors.affiliation: Laboratory of Metabolism and Lipids, Heart Institute of the Medical School Hospital, University of São Paulo, São Paulo, Brazil; Department of Clinical Chemistry, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil.
authors.forename: Iara F
authors.initials: IF
authors.lastname: Kretzer
authors.affiliation: Biochemistry and Biophysics Laboratories, Butantan Institute, São Paulo, Brazil.
authors.forename: Durvanei A
authors.initials: DA
authors.lastname: Maria
authors.affiliation: Laboratory of Metabolism and Lipids, Heart Institute of the Medical School Hospital, University of São Paulo, São Paulo, Brazil.
authors.forename: Maria C
authors.initials: MC
authors.lastname: Guido
authors.affiliation: Laboratory of Metabolism and Lipids, Heart Institute of the Medical School Hospital, University of São Paulo, São Paulo, Brazil.
authors.forename: Thaís C
authors.initials: TC
authors.lastname: Contente
authors.affiliation: Laboratory of Metabolism and Lipids, Heart Institute of the Medical School Hospital, University of São Paulo, São Paulo, Brazil; Department of Clinical Chemistry, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil.
authors.forename: Raul C
authors.initials: RC
authors.lastname: Maranhão
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D049109:Cell Proliferation / Q000187:drug effects*; D008078:Cholesterol, LDL / Q000378:metabolism; D004357:Drug Synergism; D005260:Female; D007124:Immunoenzyme Techniques; D007274:Injections, Intraperitoneal; D008055:Lipids / Q000737:chemistry*; D008546:Melanoma, Experimental / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D017239:Paclitaxel / Q000008:administration & dosage; D011973:Receptors, LDL / Q000378:metabolism; D019821:Simvastatin / Q000008:administration & dosage; D014407:Tumor Cells, Cultured
chemical_list: D008078:Cholesterol, LDL; D008055:Lipids; D011973:Receptors, LDL; D019821:Simvastatin; D017239:Paclitaxel
keywords: B16F10 melanoma; cancer treatment; drug delivery; lipid nanoparticles; statins