promising research on vorinostat for breast ca brain mets (improves radiation trtmt

[Lani]

results)

Unfortunately they used an ER- her2- breast cancer cell line for the test

but vorinostat is already in use for other cancers, oral and crosses the blood-brain-barrier readily so let's hope they examine her2+ cell lines as well and then start clinical trials

Mol Cancer Ther. 2009 Jun 9. [Epub ahead of print]

Vorinostat enhances the radiosensitivity of a breast cancer brain metastatic cell line grown in vitro and as intracranial xenografts.

Baschnagel A, Russo A, Burgan WE, Carter D, Beam K, Palmieri D, Steeg PS, Tofilon P, Camphausen K.
1Radiation Oncology Branch, 2Molecular Radiation Therapeutics Branch, and 3Laboratory of Molecular Pharmacology, National Cancer Institute, Bethesda, Maryland; 4Science Applications International Corporation-Frederick, National Cancer Institute-Frederick, Frederick, Maryland; and 5Drug Discovery Program, H. Lee Moffitt Cancer Center, Tampa, Florida.
Vorinostat (suberoylanilide hydroxamic acid), a histone deacetylase inhibitor, is currently undergoing clinical evaluation as therapy for cancer. We investigated the effects of vorinostat on tumor cell radiosensitivity in a breast cancer brain metastasis model using MDA-MB-231-BR cells. In vitro radiosensitivity was evaluated using clonogenic assay. Cell cycle distribution and apoptosis was measured using flow cytometry. DNA damage and repair was evaluated using gammaH2AX. Mitotic catastrophe was measured by immunostaining. Growth delay and intracranial xenograft models were used to evaluate the in vivo tumor radiosensitivity. Cells exposed to vorinostat for 16 hours before and maintained in the medium after irradiation had an increase in radiosensitivity with a dose enhancement factor of 1.57. gammaH2AX, as an indicator of double-strand breaks, had significantly more foci per cell in the vorinostat plus irradiation group. Mitotic catastrophe, measured at 72 hours, was significantly increased in cells receiving vorinostat plus irradiation. Irradiation of s.c. MDA-MB-231-BR tumors in mice treated with vorinostat resulted in an increase in radiation-induced tumor growth delay. Most importantly, animals with intracranial tumor implants lived the longest after combination treatment. These results indicate that vorinostat enhances tumor cell radiosensitivity in vitro and in vivo. There was a greater than additive improvement in survival in our intracranial model. Combining vorinostat with radiation may be a potential treatment option for patients with breast cancer who develop brain metastases. [Mol Cancer Ther 2009;8(6):1589-95].
PMID: 19509253