NCIt definition : An orally available small molecule selective inhibitor of ribonucleotide reductase
(RNR), with potential antineoplastic activity. Upon oral administration, RNR inhibitor
BBI-825 targets, binds to and inhibits the activity of RNR, which decreases the pool
of deoxyribonucleotide triphosphates (dNTPs) available for DNA synthesis. This disrupts
DNA synthesis and extrachromosomal DNA (ecDNA) assembly and repair, resulting in cell
cycle arrest and tumor growth inhibition. RNR, an enzyme that catalyzes the conversion
of ribonucleoside diphosphate to deoxyribonucleoside diphosphate, is essential for
de novo DNA synthesis and plays an important role in cell growth; it is overexpressed
in many cancer cell types and is associated with increased drug resistance, cancer
cell growth and metastasis.;