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Reovirus oncolysis of human breast cancer
Kara L Norman1, Matthew C Coffey, Kensuke Hirasawa
1Cancer Biology Research Group, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1 Canada.
Abstract:
We have previously shown that human reovirus replication is restricted to cells with an activated Ras pathway, and that reovirus could be used as an effective oncolytic agent against human glioblastoma xenografts. This study examines in more detail the feasibility of reovirus as a therapeutic for breast cancer, a subset of cancer in which direct activating mutations in the ras proto-oncogene are rare, and yet where unregulated stimulation of Ras signaling pathways is important in the pathogenesis of the disease. We demonstrate herein the efficient lysis of breast tumor-derived cell lines by the virus, whereas normal breast cells resist infection in vitro. In vivo studies of reovirus breast cancer therapy reveal that viral administration could cause tumor regression in an MDA-MB-435S mammary fat pad model in severe combined immunodeficient mice. Reovirus could also effect regression of tumors remote from the injection site in an MDA-MB-468 bilateral tumor model, raising the possibility of systemic therapy of breast cancer by the oncolytic agent. Finally, the ability of reovirus to act against primary breast tumor samples not propagated as cell lines was evaluated; we found that reovirus could indeed replicate in ex vivo surgical specimens. Overall, reovirus shows promise as a potential breast cancer therapeutic.
Insights
Reovirus effectively targets and destroys breast cancer cells, both in vitro and in vivo, showing promise as a novel oncolytic therapy. This virus demonstrates potential for treating breast tumors, even those distant from the administration site.
Area of Science:
- Oncology
- Virology
- Cancer Therapeutics
Background:
- Human reovirus replication is restricted to cells with activated Ras signaling.
- Ras pathway dysregulation is implicated in breast cancer pathogenesis.
- Reovirus has shown efficacy as an oncolytic agent against glioblastoma.
Purpose of the Study:
- To evaluate the feasibility of reovirus as a therapeutic agent for breast cancer.
- To investigate reovirus's efficacy against various breast cancer models.
- To assess reovirus's activity on primary breast tumor samples.
Main Methods:
- In vitro studies using breast tumor cell lines and normal breast cells.
- In vivo studies in mice using MDA-MB-435S and MDA-MB-468 breast cancer models.
- Ex vivo evaluation of reovirus replication in primary surgical breast tumor specimens.
Main Results:
- Reovirus efficiently lysed breast tumor cell lines while sparing normal breast cells.
- Viral administration led to tumor regression in mouse models, including distant tumors.
- Reovirus replicated effectively in ex vivo primary breast tumor samples.
Conclusions:
- Reovirus demonstrates significant potential as an oncolytic therapeutic for breast cancer.
- The virus exhibits selective oncolysis and efficacy in preclinical models.
- Reovirus warrants further investigation for systemic breast cancer treatment.