1. Name of presenter/research group: Dr. Tim Morgan / Prof Dennis G. Hall group
2. Therapeutic area being researched: Cancer therapy- The goal is to find a compound that can
selectively inhibit the hPNKP’s phosphatase activity to sensitize cancer cells to Radio- or
3. What is the drug target, if known? PNKP is the drug target which is required in DNA repair
process (single or double strand breaks). It’s an enzyme that phosphorylates the 5’ end of DNA and
dephosphorylates the 3’ end of DNA. If we can find a molecule to inhibit its activity, we can
decrease the survival rate of cancer cells when exposed to genotoxic agents such as ionizing
radiation, camptothecin and alkylating agent.
4. What class or classes or molecular structures were examined? Substituted imidopiperidine
5. What was the rationale for studying these compounds? In 1998, the first substituted
imidopiperidine was synthesized. Since researchers found out these molecules can inhibit PNKP
activity, they prepared a diversity library of 944 imidopiperidine derivations which 244 of them was
screened in Fluorescent assay. Only 5 compounds of these 244 compounds were active against
PNKP (A12B4C3, A1B4C3, A6B4C3, A26B11C2, and A39B1C2). Finally A12B4C3 was accepted
as the optimized lead.
6. What was the read-out used to evaluate compounds?
Fluorescent assay (In this assay if the PNKP is active, the fluorescent probe will be quenched
and there is not any Fluorescent light available. However, if we can inhibit PNKP’s activity, the
probe is not quenched and we can see fluorescent light).
7. What were the results that were found?
A12B4C3 inhibition activity: Low IC =504 µM, Lo