[Webinar] Targeting PARP Synthetic Lethality: An HTS Assay for Cancer Drug Discovery

Poly(ADP-ribose) polymerases (PARPs) are central to DNA damage repair, and selective inhibition has emerged as a powerful synthetic lethality strategy. PARP inhibitors have already transformed the treatment of BRCA1/2-mutant cancers and continue to expand into breast, ovarian, prostate, and pancreatic indications.

To accelerate the discovery of next-generation PARP inhibitors, BellBrook Labs has developed a robust, high-throughput assay for PARP activity that enables quantitative detection of poly(ADP-ribose) (pADPr) formation in a simple, mix-and-read format.

The Transcreener® pADPr PARP Assay offers sensitive readouts via fluorescence polarization (FP) or TR-FRET. Based on the trusted Transcreener platform, using enzymatic conversion of pADPr to AMP, enables a simple but robust inhibitor screening assay designed for HTS. Whether you’re advancing oncology pipelines, building HTS campaigns, or exploring synthetic lethality, this webinar will give you practical insights and a new tool to streamline PARP drug discovery. This webinar is free to attend.

Webinar Details:

Thursday, September 25th
10:00 AM CDT / 11:00 AM EDT
Duration: 45 Minutes
Host: Mahbbat Ali Ph.D, Senior Scientist at BellBrook Labs

Accelerate your discovery of next-generation PARP inhibitors.

Abstract:

Poly(ADP-ribose) polymerases (PARPs) initiate DNA damage repair (DDR) by binding to double strand breaks and creating a scaffold of poly(ADP-ribose) (pADPr) chains for assembly of other DDR proteins. The use of PARP inhibitors for ovarian tumors with BRCA-1 mutations was the first clinical exploitation of synthetic lethality, and PARP inhibitors are now used for breast, prostate, pancreatic, and ovarian cancers. New types of PARP inhibitors are being sought to broaden the scope of indications. To facilitate this effort, we developed a high throughput screening (HTS) assay for PARPs that enables quantitative detection of pADPr formation in a homogenous format. The assay relies on enzymatic conversion of pADPr to AMP, which is then detected using the Transcreener AMP/GMP assay with a fluorescence polarization (FP) or time-resolved Förster resonance energy transfer (TR-FRET) readout. To minimize interference from screening compounds, we first optimized the concentration of coupling enzymes to ensure that the pADPr will be completely converted to AMP even if the conversion reaction is inhibited by as much as 80%. Using this optimized system, the assay produced a robust signal (Z’ > 0.8) using 0.8 nM PARP1 and 3.2 nM PARP2, with sub-saturating NAD (100 μM) and saturating DNA (0.25 mg/mL) under initial velocity conditions. The assay was validated for HTS using a 1,280 compound bioactive library, resulting in 18 hits, 5 of which proved to be interference. We also screened a 3,200 compound diversity library, resulting in 44 hits, 3 of which were identified as interference. Four known PARP1 inhibitors, Olaparib, PJ 34 HCl, Veliparib, and Rucaparib Camsylate, were detected in the bioactive screen and tested in dose response mode with both FP and TR-FRET readout; the measured IC50 values (0.45 nM, 29 nM, 1.4 nM and 0.4 nM, respectively) were consistent with published values. By enabling sensitive, quantitative detection of pADPr formation in a simple, mix-and-read format, the Transcreener pADPr PARP Assay should facilitate efforts to develop more effective PARP inhibitors.

In this webinar, you’ll learn:

• Why PARP inhibition is a cornerstone of synthetic lethality in oncology
• How our HTS-compatible assay was optimized to minimize compound interference and ensure robust pADPr detection
• How we validated the assay with Z’ > 0.8 using PARP1 and PARP2 under initial velocity conditions
• Results from screening over 4,000 compounds, including successful identification of known inhibitors (Olaparib, Veliparib, Rucaparib, PJ34) with published IC₅₀ alignment
• How this assay platform supports HTS, SAR, and lead discovery for PARP inhibitor programs