pol-ii

YKL-5-124, a potent, selective and covalent CDK7 inhibitor with an IC50 of 9.7 nM, 1300 nM and 3020 nM for CDK7 Mat1 CycH, CDK2 and CDK9 respectively, displays biochemical and cellular selectivity for CDK7 over CDK12 13.

Samuraciclib hydrochloride (ICEC0942 hydrochloride) is a potent, selective, ATP competitive and oral active CDK7 inhibitor with IC50 of 41 nM. The selectivity of Samuraciclib hydrochloride is 45-, 15-, 230- and 30-fold higher than CDK1, CDK2 (IC50 is 578 nM), CDK5 and CDK9 respectively. Samuraciclib hydrochloride inhibits the growth of breast cancer cell lines with GI50 values between 0.2-0.3 μM. Samuraciclib hydrochloride has anti-tumor effects.

SEC inhibitor KL-1 (KL-1) is a potent, selective super elongation complex (SEC) inhibitor that exhibits a dose-dependent inhibitory effect on AFF4-CCNT1 interaction (Ki: 3.48 μM) and disrupts the interaction between the SEC scaffolding protein AFF4.

SEC inhibitor KL-2 (KL-2) is a potent and selective inhibitor of the super elongation complex (SEC), showing a dose-dependent inhibitory effect on the AFF4-CCNT1 interaction with a Ki of 1.50 μM.

Toyocamycin (Vengicide) is an adenosine analog produced by Actinomycetes, functioning as an XBP1 inhibitor and inhibiting IRE1α-induced ATP-dependent XBP1 mRNA cleavage (IC50: 80 nM), and induces apoptosis.

CX-5461 dihydrochloride is a potent, orally active inhibitor of Pol I-mediated rRNA synthesis that acts on HCT-116 cells (IC50: 142 nM), A375 cells (IC50: 113 nM) and MIA PaCa-2 cells (IC50: 54 nM), and to a lesser extent on Pol II (IC50 ≥ 25 μM).

Pidnarulex HCl is the salt form of CX-5461, a first-in-class non-genotoxic small molecule targeted inhibitor of RNA polymerase I (Pol I) that activates the p53 pathway without causing DNA damage. CX-5461 selectively inhibits rRNA synthesis by Pol I in the nucleolus, but does not inhibit mRNA synthesis by RNA Polymerase II (Pol II) and does not inhibit DNA replication or protein synthesis. Inhibition of Pol I results in nucleolar stress and release of ribosomal proteins (RP) from the nucleolus. The RP bind to Mdm2 and liberate p53 to orchestrate apoptosis in cancer cells. CX-5461 demonstrates a favorable preclinical profile, potently and selectively kills cancer cells, demonstrates robust in vivo efficacy in multiple models, and has demonstrated oral bioavailability in multiple species.

MFH290 is a novel cysteine (Cys)-directed covalent inhibitor of CDK12 13. MFH290 forms a covalent bond with Cys-1039 of CDK12, exhibits excellent kinome selectivity, inhibits the phosphorylation of serine-2 in the C-terminal domain (CTD) of RNA-polymerase II (Pol II), and reduces the expression of key DNA damage repair genes. Importantly, these effects were demonstrated to be CDK12-dependent as mutation of Cys-1039 rendered the kinase refractory to MFH290 and restored Pol II CTD phosphorylation and DNA damage repair gene expression. Consistent with its effect on DNA damage repair gene expression, MFH290 augments the antiproliferative effect of the PARP inhibitor olaparib.

RNA polymerase II-IN-1 (compound 19iv), an amatoxin, selectively inhibits RNA polymerase II (Pol II) with an IC50 of 36.66 nM and exhibits heightened cytotoxicity towards cancer cells while reducing toxicity in normal cells compared to α-Amanitin [1].

RNA polymerase II-IN-2 (compound 20iii), a potent inhibitor of RNA polymerase II (Pol II) with a K i value of 9.5 nM, exhibits cytotoxicity against cancer cells, demonstrating toxicity levels 2 and 5 times higher than α-amanitin in CHO and HEK293 cells, respectively [1].

CDK9-Cyclin T1 PPI-IN-1 (Compound B19) is a selective inhibitor of the CDK9-Cyclin T1 protein-protein interaction (PPI), suppressing cell proliferation in TNBC MDA-MB-231 cells with an IC50 of 0.044 μM and inducing apoptosis. This compound diminishes CDK9 transcriptional activity and downregulates phosphorylation of RNA Pol II CTD ser2. In vivo, CDK9-Cyclin T1 PPI-IN-1 effectively impedes tumor growth in a TNBC 4T1 mouse model [1].