(ChemotherapyAdvisor) – Treating breast cancer using RNA interference could become a reality, according to researchers in the Program in Cellular and Molecular Medicine at Boston Children’s Hospital and the Immune Disease Institute (PCMM/IDI). The study, entitled “Targeted Delivery of PLK1-siRNA by ScFv Suppresses Her2-positive Breast Cancer Growth and Metastasis,” was published April 20 in Science Translational Medicine

In this study, researchers bound siRNAs capable of silencing PLK1 (an enzyme that promotes cell division) to protamine, a peptide that shrink-wraps DNA in sperm cells. Attachment of protamine to an antibody fragment (called ScFv) against HER2 created the delivery package addressed directly to breast cancer cells with HER2 on their surface.

“Once in the tumors, the siRNAs were absorbed into tumor cells, where they turned off PLK1, retarding tumor growth and suppressing metastasis compared to untreated controls or those that received naked siRNAs. The team found no evidence of inflammation or toxicity in the liver, kidneys, or bloodstream, indicating that the siRNAs were silencing PLK1 only in their intended targets, the breast cancer cells,” the authors wrote.

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Says Judy Lieberman, MD, PhD, senior investigator, Immune Disease Institute and Program in Cellular and Molecular Medicine: “The platform could be used to target siRNAs therapeutically to any cell for which we have a cell surface marker to target. We have also used it to target lymphocytes, suggesting it could be useful against lymphomas and leukemias and as a way of countering organ rejection.”

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