title: Bcl-2 and glutathione depletion sensitizes B16 melanoma to combination therapy and eliminates metastatic disease.
abstract: OBJECTIVE
  Advanced melanoma resists all current therapies, and metastases in the liver are particularly problematic. Prevalent resistance factors include elevated glutathione (GSH) and increased expression of bcl-2 in melanoma cells. GSH has pleiotropic effects promoting cell growth and broad resistance to therapy, whereas Bcl-2 inhibits the activation of apoptosis and contributes to elevation of GSH. This study determined the in vivo efficacy of combination therapies administered while GSH and Bcl-2 were individually and simultaneously decreased in metastatic melanoma lesions.
  
  
  METHODS
  Highly metastatic murine B16 melanoma (B16M-F10) cells have elevated levels of both GSH and Bcl-2. B16M-F10 cells were injected i.v. to establish metastatic lesions in vivo. GSH was decreased using an L-glutamine--enriched diet and administration of verapamil and acivicin, whereas Bcl-2 was reduced using oligodeoxynucleotide G3139. Paclitaxel, X-rays, tumor necrosis factor-alpha, and IFN-gamma were administered as a combination therapy.
  
  
  RESULTS
  Metastatic cells were isolated from liver to confirm the depletion of GSH and Bcl-2 in vivo. Reduction of Bcl-2 and GSH, combined with partial therapies, decreased the number and volume of invasive B16M-F10 foci in liver by up to 99% (P<0.01). The full combination of paclitaxel, X-rays, and cytokines eliminated B16M-F10 cells from liver and all other systemic disease, leading to long-term survival (>120 days) without recurrence in 90% of mice receiving the full therapy. Toxicity was manageable; the mice recovered quickly, and hematology and clinical chemistry data were representative of accepted clinical toxicities.
  
  
  CONCLUSIONS
  Our results suggest a new strategy to induce regression of late-stage metastatic melanoma.
authors.affiliation: Department of Physiology, Faculty of Medicine and Odontology, University of Valencia, Valencia, Spain.
authors.forename: Salvador
authors.initials: S
authors.lastname: Mena
authors.forename: María
authors.initials: M
authors.lastname: Benlloch
authors.forename: Angel
authors.initials: A
authors.lastname: Ortega
authors.forename: Julian
authors.initials: J
authors.lastname: Carretero
authors.forename: Elena
authors.initials: E
authors.lastname: Obrador
authors.forename: Miguel
authors.initials: M
authors.lastname: Asensi
authors.forename: Ignacio
authors.initials: I
authors.lastname: Petschen
authors.forename: Bob D
authors.initials: BD
authors.lastname: Brown
authors.forename: José M
authors.initials: JM
authors.lastname: Estrela
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D005973:Glutamine / Q000008:administration & dosage; D005978:Glutathione / Q000037:antagonists & inhibitors*; D008546:Melanoma, Experimental / Q000188:drug therapy / Q000532:radiotherapy / Q000628:therapy*; D051379:Mice; D009362:Neoplasm Metastasis; D017239:Paclitaxel / Q000627:therapeutic use*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors* / Q000235:genetics; D012878:Skin Neoplasms / Q000188:drug therapy / Q000532:radiotherapy / Q000628:therapy*; D013873:Thionucleotides / Q000494:pharmacology; D016896:Treatment Outcome; D014409:Tumor Necrosis Factor-alpha / Q000627:therapeutic use*; D014965:X-Rays
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D019253:Proto-Oncogene Proteins c-bcl-2; D013873:Thionucleotides; D014409:Tumor Necrosis Factor-alpha; D005973:Glutamine; C408162:oblimersen; D005978:Glutathione; D017239:Paclitaxel