CX-5461

A cell-permeable benzothiazole compound that selectively inhibits RNA polymerase I-mediated pre-rRNA transcription (IC₅₀ = 142, 113, 54, and 74 nM in HCT-116, A375, MIA PaCa-2, and BJ-hTert cells, respectively), but not Pol II-mediated c-myc transcription, by preventing TAF (TATA Binding Protein-/TBP-Associated Factor) SL1 and rDNA association, effectively inhibiting Pol I-dependent proliferation among 39 cancer cell lines (IC₅₀<1 µM) in vitro. While Pol I inhibition by CX-5461 is shown to result in p53-dependent apoptosis in cancer cells of hematopoietic origin, cell death by CX-5461 treatment in solid tumors-derived A375 and MIA PaCa-2 cultures are primarily due to autophagy and senescence, but not apoptosis, induction. Shown to suppress A375 (50 mg/kg/d p.o.) and MIA PaCa-2 (50 mg/kg/3d p.o.) tumor expansion, as well as selectively induce p53-mediated cell death of Eμ-Myc lymphoma, but not normal B cells, in mice (50 mg/kg p.o.) in vivo.

Cell permeable: yes

Primary Target
Pol I multi-protein complex

Reversible: yes

Packaged under inert gas

Haddach, M., et al. 2012. ACS Med. Chem. Lett.3, 602.
Bywater, M.J., et al. 2012. Cancer Cell22, 51.
Drygin, D., et al. 2011. Cancer Res71, 1418.

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Toxicity: Standard Handling (A)