Bortezomib Enhances the Antitumor Effects of Interferon-β Gene Transfer on Melanoma Cells.
BACKGROUND
Malignant melanoma is a fast growing form of skin cancer with increasing global incidence. Clinically, canine malignant melanoma and human melanoma share comparable treatment-resistances, metastatic phenotypes and site selectivity.


OBJECTIVE
Both interferon-β (IFNβ) and bortezomib (BTZ) display inhibitory activities on melanoma cells. Here, we evaluated the cytotoxic effects of the combination of BTZ and IFNβ gene lipofection on cultured melanoma cell lines.


METHODS
Cell viability determined by the acid phosphatase method, cell migration mesasured by the wound healing assay, DNA fragmentation and cell cycle by flow cytometry after propidium iodide staining and reactive oxygen species (ROS) production by H2DCF-DA fluorescence.


RESULTS
Four canine mucosal (Ak, Br, Bk and Ol) and two human dermal (A375 and SB2) melanoma cell lines were assayed. BTZ sub-pharmacological concentrations (5 nM) enhanced the cytotoxic effects of IFNβ transgene expression on melanoma cells monolayers and spheroids. The combination was also more effective than the single treatments when assayed for clonogenic survival and cell migration. The combined treatment produced a significant raise of apoptosis evidenced by DNA fragmentation as compared to either BTZ or IFNβ gene lipofection single treatments. Furthermore, BTZ significantly increased the intracellular ROS generation induced by IFNβ gene transfer in melanoma cells, an effect that was reversed by the addition of the ROS inhibitor N-acetyl-L-cystein.


CONCLUSIONS
The present work encourages further studies about the potential of the combination of interferon gene transfer with proteasome inhibitors as a new combined therapy for malignant melanoma, both in veterinary and/or human clinical settings.
Unidad de Transferencia Genetica, Instituto de Oncologia, Argentina.
Ursula A
UA
Rossi
Unidad de Transferencia Genetica, Instituto de Oncologia, Argentina.
Liliana M E
LME
Finocchiaro
Unidad de Transferencia Genetica, Instituto de Oncologia, Argentina.
Gerardo C
GC
Glikin
D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D000069286:Bortezomib / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D015316:Genetic Therapy; D006801:Humans; D016899:Interferon-beta / Q000235:genetics*; D008081:Liposomes / Q000378:metabolism; D008545:Melanoma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D015394:Molecular Structure; D017382:Reactive Oxygen Species / Q000378:metabolism; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D008081:Liposomes; D017382:Reactive Oxygen Species; D000069286:Bortezomib; D016899:Interferon-beta
Bortezomib; ROS; canine; human; interferon-β; lipofection; melanoma; spheroids