Abstract 5529: Silencing H-ferritin by siRNA delivered by cationic liposomes increases chemotherapeutic sensitivity for treating malignant tumor
| Autor: | Becky Slagle-Webb, Xiaoli Liu, A.B. Madhankumar, James R. Connor, Jonas M. Sheehan, Nodar Surguladze |
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| Rok vydání: | 2010 |
| Předmět: | |
| Zdroj: | Cancer Research. 70:5529-5529 |
| ISSN: | 1538-7445 0008-5472 |
| DOI: | 10.1158/1538-7445.am10-5529 |
| Popis: | Cancer cells have a robust appetite for iron to support their rapid growth and high metabolic rates. The high levels of iron uptake require a mechanism to limit iron induced oxidative damage. This function is the responsibility of ferritin; an intracellular iron storage protein. Ferritin has been found in the nucleus of tumor cells where it appears to protect DNA from iron induced oxidative damage and promote transcription. Therefore, we hypothesized that silencing H-ferritin gene expression could increase the sensitivity of malignant tumors to radiation and chemotoxins. Potentially targets of H-ferritin disrupted iron homeostasis in tumor cells result in proving effective at negatively affecting tumor growth. To test our hypothesis, H-ferritin siRNA was delivered to U251 human astrocytoma cells, malignant peripheral nerve sheath tumor (MPNST) cells and a breast cancer cell line (MCF-7) via our cationic liposomes. Western immunoblotting analysis demonstrated that the siRNA delivered in this manner decreased H-ferritin protein expression by 70 to 80% in all three cell lines within 48 hours. The results from SRB assay displayed decrease H-ferritin was associated with a decrease in the LD50 for carmustine (BCNU) from greater than 100 µM to 40 μM in the U251 cells, 30 µM in MCF7 cells and 18 µM in MPNST cells. In addition, the results of MTS assay revealed the presence of H-ferritin siRNA was associated with a 50% increase in cell death of U251 cells at 20 Gy of radiation. The in vivo efficacy of siRNA delivered by cationic-liposomes was tested in the Athymic nude mice subcutaneous glioma tumor model. Intratumoral injections of cationic liposomes containing H-ferritin siRNA reduced the required effective dose of BCNU for tumor suppression by more than 50%. The interaction of H-ferritin with DNA was investigated in vitro by supercoil relaxation assay, which demonstrated that H-ferritin maintained DNA in a relaxed form that would promote transcription of DNA even in the presence of radiation and chemotoxins. The outcome of study for Caspase-3 activity exposed that transfection with H-ferritin siRNA was associated with activation of apoptotic caspase pathway. Overall, our data demonstrated that silencing the H-ferritin gene appears to be an effective way to sensitize tumors to radiation and chemotherapy. As importantly, we have demonstrated that siRNA can be delivered effectively by cationic liposomes in an in vivo tumor model. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5529. |
| Databáze: | OpenAIRE |
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