CX5461 is an rRNA synthesis inhibitor with oral activity that inhibits Pol I-driven rRNA transcription. CX5461 activates the DNA damage response and has antitumor activity in tumors such as ovarian cancer.

Pol I-driven transcription of rRNA:142 nM

METHODS: The phytopathogenic fungi A. tubingensis, Nigrospora oryzae and Phoma herbarum were treated with Carviolin (1-512 µg/mL) for 18 h and subjected to Antifungal Assay.
RESULTS: Carviolin showed antifungal activity with MIC less than 200 µg/mL against all three fungi. [1]

In a mouse model of xenograft human solid tumors, oral administration of CX-5461 (50 mg/kg) demonstrated antitumor activity against solid tumors.

Pol I and Pol II Transcription Assay: Two short-lived RNA transcripts (half-lives ~20-30 minutes), one produced by Pol I and another by Pol II, are quantitated by qRT-PCR as a measure of CX-5461-related effects on transcription. The 45S pre-rRNA served as the Pol I transcript and the mRNA for the protooncogene c-myc served as the comparator Pol II transcript. Both Pol I and Pol II transcription are known to be affected by general cellular stress. To minimize the potential effects of such stress, cells are exposed to test agents for only a short period of time (2 hours). This is sufficient time for these transcripts to be reduced by greater than 90% if CX-5461 affects their synthesis.

Cells are plated on 96-well plates and treated the next day with dose response of CX-5461 for 96 hours. Cell viability is determined using Alamar Blue and CyQUANT assays(Only for Reference)