Poly (ADP-ribose) polymerases (PARPs) are a family of enzymes involved in various cellular processes, including DNA repair, genomic stability, and programmed cell death. PARP enzymes detect and respond to DNA damage by adding ADP-ribose polymers to target proteins, facilitating the recruitment of repair proteins to sites of damage. Dysregulation of PARP activity is implicated in a variety of diseases, particularly cancer, where PARP inhibitors have emerged as a promising therapeutic strategy, especially in tumors with defective DNA repair mechanisms, such as BRCA1/2-mutated cancers.

PARP Enzymatic Assays

We use the ELISA method to detect the enzymatic activity of the PARP family of ADP-ribose polymerases. Histones are coated on the plate, and PARP proteins (PARP1/2/3 require single-strand DNA breaks for activation) along with biotin-labeled NAD are added. As the reaction progresses, PARP1 forms biotin-labeled ADP-ribose chains on the histones. Then, streptavidin-labeled HRP and an ultrasensitive detection reagent are added to detect the signal.

We also have extensive experience in PARP panel selectivity screening. Below is our data of the testing of Olaparib and AZD5305.

PARP Trapping Assay

When PARP forms a complex with DNA and NAD, it dissociates from the DNA as ADP-ribose chains are generated. Biotin labels are added to single-stranded DNA breaks, and PARP proteins are tagged with His tags. When inhibitors are added, PARP does not dissociate from the DNA, allowing for the detection of fluorescence resonance energy transfer signals between donor and acceptor tags.

Cancer Cell Panel Screening for PARP

For the PARP target, we have launched a Cell Panel for PARP inhibitor screening, including 9 types of cancer with a total of 70 tumor cell lines. This includes PARP knockout cell lines, BRCA knockout cell lines, BRCA overexpressing cell lines, BRCA mutant cell lines, PARP inhibitor-resistant cell lines, and general tumor cell lines. This cell panel can be used for compound testing over 7-14 days, either as monotherapy or in combination, and we also offer customized solutions based on client needs.