Electroporation increases antitumoral efficacy of the bcl-2 antisense G3139 and chemotherapy in a human melanoma xenograft.

Abstract

BACKGROUND:

Nucleic acids designed to modulate the expression of target proteins remain a promising therapeutic strategy in several diseases, including cancer. However, clinical success is limited by the lack of efficient intracellular delivery. In this study we evaluated whether electroporation could increase the delivery of antisense oligodeoxynucleotides against bcl-2 (G3139) as well as the efficacy of combination chemotherapy in human melanoma xenografts.

METHODS:

Melanoma-bearing nude mice were treated i.v. with G3139 and/or cisplatin (DDP) followed by the application of trains of electric pulses to tumors. Western blot, immunohistochemistry and real-time PCR were performed to analyze protein and mRNA expression. The effect of electroporation on muscles was determined by histology, while tumor apoptosis and the proliferation index were analyzed by immunohistochemistry. Antisense oligodeoxynucleotides tumor accumulation was measured by FACS and confocal microscopy.

RESULTS:

The G3139/Electroporation combined therapy produced a significant inhibition of tumor growth (TWI, more than 50%) accompanied by a marked tumor re-growth delay (TRD, about 20 days). The efficacy of this treatment was due to the higher G3139 uptake in tumor cells which led to a marked down-regulation of bcl-2 protein expression. Moreover, the G3139/EP combination treatment resulted in an enhanced apoptotic index and a decreased proliferation rate of tumors. Finally, an increased tumor response was observed after treatment with the triple combination G3139/DDP/EP, showing a TWI of about 75% and TRD of 30 days.

CONCLUSIONS:

These results demonstrate that electroporation is an effective strategy to improve the delivery of antisense oligodeoxynucleotides within tumor cells in vivo and it may be instrumental in optimizing the response of melanoma to chemotherapy. The high response rate observed in this study suggest to apply this strategy for the treatment of melanoma patients.

• Authors: Enrico P Spugnini, Annamaria Biroccio, Roberta De Mori, Marco Scarsella, Carmen D'Angelo, Alfonso Baldi, Carlo Leonetti
• Journal: Journal of translational medicine (J Transl Med) Vol. 9 Pg. 125 (Jul 28 2011) ISSN: 1479-5876 [Electronic] England
• PMID: 21798045 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antineoplastic Agents
• Neoplasm Proteins
• Oligonucleotides, Antisense
• Proto-Oncogene Proteins c-bcl-2
• RNA, Messenger
• Thionucleotides
• oblimersen
• Cisplatin

Topics

• Animals
• Antineoplastic Agents (pharmacology, therapeutic use)
• Apoptosis (drug effects)
• Cell Line, Tumor
• Cell Proliferation (drug effects)
• Cisplatin (pharmacology, therapeutic use)
• Combined Modality Therapy
• Down-Regulation (drug effects)
• Electrodes
• Electroporation (methods)
• Gene Expression Regulation, Neoplastic (drug effects)
• Humans
• Melanoma (drug therapy, genetics, pathology)
• Mice
• Muscle, Skeletal (drug effects, pathology)
• Neoplasm Proteins (genetics, metabolism)
• Oligonucleotides, Antisense (pharmacology, therapeutic use)
• Proto-Oncogene Proteins c-bcl-2 (metabolism)
• RNA, Messenger (genetics, metabolism)
• Thionucleotides (pharmacology, therapeutic use)
• Treatment Outcome
• Xenograft Model Antitumor Assays