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Published on: February 8, 2017
Adeno-associated virus-mediated trastuzumab delivery to the central nervous system for human epidermal growth factor
Marcela S Werner1, Shweta Aras1, Ashleigh R Morgan1
1Gene Therapy Program, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
Abstract:
Trastuzumab improves overall survival for HER2+ breast cancer, but its short half-life in the cerebrospinal fluid (~2-4 days) and delivery limitations restrict the ability to target HER2+ central nervous system (CNS) disease. We developed an adeno-associated virus (AAV) vector expressing a codon-optimized, ubiquitin C (UbC)-promoter-driven trastuzumab sequence (AAV9.UbC.trastuzumab) for intrathecal administration. Transgene expression was evaluated in adult Rag1 knockout mice and rhesus nonhuman primates (NHPs) after a single intracerebroventricular (ICV) or intra-cisterna magna (ICM) AAV9.UbC.trastuzumab injection, respectively, using real-time PCR, ELISA, Western blot, in situ hybridization, single-nucleus RNA sequencing, and liquid chromatography-mass spectrometry; antitumor efficacy was evaluated in brain xenografts using HER2+ breast cancer cell lines (BT-474, MDA-MB-453). Transgene expression was detected in brain homogenates of Rag1 knockout mice following a single ICV injection of AAV9.UbC.trastuzumab (1 × 1011 vector genome copies [GC]/mouse) and tumor progression was inhibited in xenograft models of breast-to-brain metastasis. In NHPs, ICM delivery of AAV9.UbC.trastuzumab (3 × 1013 GC/animal) was well tolerated (36-37 days in-life) and resulted in transgene expression in CNS tissues and cerebrospinal fluid at levels sufficient to induce complete tumor remission in MDA-MB-453 brain xenografts. With AAV9's proven clinical safety record, this gene therapy may represent a viable approach for targeting HER2 + CNS malignancies.
Insights
A novel gene therapy using adeno-associated virus (AAV) vector delivered Trastuzumab to the central nervous system (CNS) for HER2+ breast cancer brain metastases. This approach demonstrated effective tumor inhibition and may offer a new treatment strategy for CNS malignancies.
Area of Science:
- Oncology
- Gene Therapy
- Neuroscience
Background:
- Trastuzumab is effective for HER2+ breast cancer but has limitations in targeting CNS disease due to short cerebrospinal fluid half-life.
- Targeting HER2+ central nervous system (CNS) disease remains a challenge for current therapies.
Purpose of the Study:
- To develop and evaluate an adeno-associated virus (AAV) vector-based gene therapy for intrathecal delivery of Trastuzumab to treat HER2+ CNS malignancies.
- To assess the safety and efficacy of AAV9.UbC.trastuzumab in preclinical models.
Main Methods:
- An adeno-associated virus (AAV) vector (AAV9.UbC.trastuzumab) was engineered for intrathecal administration.
- Transgene expression and biodistribution were analyzed in mice and nonhuman primates (NHPs) using various molecular techniques.
- Antitumor efficacy was evaluated in HER2+ breast cancer brain xenograft models.
Main Results:
- AAV9.UbC.trastuzumab administration led to detectable transgene expression in the CNS of mice and NHPs.
- The gene therapy was well-tolerated in NHPs over a 36-37 day observation period.
- Complete tumor remission was achieved in HER2+ breast cancer brain xenografts in NHPs.
Conclusions:
- Intrathecal delivery of AAV9.UbC.trastuzumab provides sustained Trastuzumab expression in the CNS.
- This gene therapy approach shows promise for treating HER2+ breast cancer brain metastases.
- AAV9.UbC.trastuzumab represents a potential new therapeutic strategy for HER2+ CNS malignancies.
