Olomoucine II is an inhibitor of cyclin-dependent kinases (CDKs; IC50s = 7.6, 0.1, 19.8, 0.45, and 0.06 μM for Cdk1, -2, -4, -7, and -9, respectively).1It is selective for CDKs over 10 additional kinases (IC50s = >100 μM for all) but does inhibit ERK2 (IC50= 32 μM) and the ATP-binding cassette transporter B1 (ABCB1; IC50= 6.4 μM).1,2Olomoucine II inhibits proliferation of a variety of cancer cells, including those expressing wild-type p53 or mutant p53 (mean IC50s = 7.4 and 10.1 μM, respectively), and it acts synergistically with daunorubicin to inhibit proliferation of HCT-8 cells that endogenously express ABCB1. Olomoucine also inhibits replication of herpes simplex virus 1 (HSV-1), HSV-2, vacciniavirus, human adenovirus type 4 (Ad4), and human CMV (IC50s = 5, 4.7, 3.8, 2.4, and 3.2 μM, respectively) but not measles virus or influenza virus (IC50s = >20 μM for both).3
EICAR is a drug which acts as an inhibitor of the enzyme IMP dehydrogenase. It is a nucleoside derivative which has both anti-cancer and antiviral effects, and was originally developed for the treatment of leukemia, but was unsuccessful in human clinical trials. It has broad spectrum antiviral effects with activity against vacciniavirus, Semliki forest virus, Junin virus, reovirus, influenza, measles virus and respiratory syncytial virus among others, although it is not active against SARS. This useful spectrum of activity means that EICAR and related derivatives continue to be investigated for the treatment of viral diseases.
5'-Ethynyl-2'-deoxycytidine (EdC) functions as a nucleoside analog effectively inhibiting the replication of herpes simplex virus-1 (HSV-1) KOS strain with an ID50 of 0.2 μg mL. Additionally, it decreases virus-induced cytopathogenic effects in PRK cells for HSV-1, HSV-2, and vacciniavirus strains, demonstrating MIC values between 0.2 to 5 μg mL. EdC acts as a thymidylate synthetase inhibitor, selectively impacting the DNA incorporation rates of [1',2'-3H]deoxyuridine compared to [CH3-3H]deoxythymidine in PRK cells with ID50s of 3 and 120 μg mL, respectively. It further inhibits thymidine synthetase and curtails L1210 cell proliferation, a process reversible by deoxythymidine (ID50s are 4.4 and 1,000 μg mL, respectively). Also, EdC is utilized in monitoring DNA synthesis and cellular replication through click chemistry conjugation, linking its ethynyl group with the azido group of various fluorochromes.