KX-01, a novel Src kinase inhibitor directed toward the peptide substrate site, synergizes with tamoxifen in estrogen receptor alpha positive breast cancer.
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Anbalagan M, Carrier L, Glodowski S, Hangauer D, Shan B, Rowan BG
KX-01, a novel Src kinase inhibitor directed toward the peptide substrate site, synergizes with tamoxifen in estrogen receptor alpha positive breast cancer.
Breast Cancer Res Treat. 2012 Apr;132(2):391-409. doi: 10.1007/s10549-011-1513-3. Epub 2011 Apr 21.
- PubMed ID
- 21509526 [ View in PubMed]
- Abstract
KX-01 is the first clinical Src inhibitor of the novel peptidomimetic class that targets the peptide substrate site of Src providing more specificity toward Src kinase. The present study was designed to evaluate the effects of KX-01 as a single agent and in combination with tamoxifen (TAM) on cell growth and apoptosis of ERalpha positive breast cancer in vitro and in vivo. Flow cytometry demonstrated that KX-01 induced cell cycle arrest in G2/M phase. Immunofluorescent staining for mitotic phase markers and TUNEL staining indicated that cells had arrested in the mitotic phase and mitotic arrested cells were undergoing apoptosis. KX-01 induced nuclear accumulation of cyclin B1, and activation of CDK1, MPM2, and Cdc25C that is required for progression past the G2/M checkpoint. Apoptosis resulted from activation of caspases 6, 7, 8, and 9. Combinational index analysis revealed that combinations of KX-01 with TAM resulted in synergistic growth inhibition of breast cancer cell lines. KX-01 combined with TAM resulted in decreased ERalpha phosphorylation at Src-regulated phosphorylation sites serines 118 and 167 that were associated with reduced ERalpha transcriptional activity. Orally administered KX-01 resulted in a dose dependent growth inhibition of MCF-7 tumor xenografts, and in combination with TAM exhibited synergistic growth inhibition. Immunohistochemical analysis revealed that combinational treatment reduced angiogenesis, and ERalpha signaling in tumors compared to either drug alone that may underlie the synergistic tumor growth inhibition. Combinations of KX-01 with endocrine therapy present a promising new strategy for clinical management of ERalpha positive breast cancer.
DrugBank Data that Cites this Article
- Drugs
- Drug Targets
Drug Target Kind Organism Pharmacological Action Actions Tirbanibulin Proto-oncogene tyrosine-protein kinase Src Protein Humans YesInhibitorDetails