DNA damage induced by KP372-1 hyperactivates PARP1 and enhances lethality of pancreatic cancer cells with PARP inhibition

Talysa Viera,Praveen L Patidar

doi:10.1038/s41598-020-76850-4

Talysa Viera, Praveen L Patidar

Open Access

https://doi.org/10.1038/s41598-020-76850-4

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Abstract

The overall prognosis for pancreatic cancer remains dismal and potent chemotherapeutic agents that selectively target this cancer are critically needed. Elevated expression of NAD(P)H:quinone oxidoreductase 1 (NQO1) is frequent in pancreatic cancer, and it offers promising tumor-selective targeting. Recently, KP372-1 was identified as a novel NQO1 redox cycling agent that induces cytotoxicity in cancer cells by creating redox imbalance; however, the mechanistic basis of KP372-1-induced cytotoxicity remains elusive. Here, we show that KP372-1 sensitizes NQO1-expressing pancreatic cancer cells and spares immortalized normal pancreatic duct cells, hTERT-HPNE. Notably, we found that KP372-1 is ~ 10- to 20-fold more potent than β-lapachone, another NQO1 substrate, against pancreatic cancer cells. Mechanistically, our data strongly suggest that reactive oxygen species produced by NQO1-dependent redox cycling of KP372-1 cause robust DNA damage, including DNA breaks. Furthermore, we found that KP372-1-induced DNA damage hyperactivates the central DNA damage sensor protein poly(ADP-ribose) polymerase 1 (PARP1) and activates caspase-3 to initiate cell death. Our data also show that the combination of KP372-1 with PARP inhibition creates enhanced cytotoxicity in pancreatic cancer cells. Collectively, our study provides mechanistic insights into the cytotoxicity instigated by KP372-1 and lays an essential foundation to establish it as a promising chemotherapeutic agent against cancer.

Highlights

Abbreviations DIC Dicoumarol β-lap β-Lapachone N-acetylcysteine amide (NAC) N-Acetylcysteine amide NAD(P)H:Quinone Oxidoreductase 1 (NQO1) NAD(P)H:quinone oxidoreductase 1 poly(ADP-ribose) polymerase 1 (PARP1) Poly(ADP-ribose) polymerase 1 PARPi PARP inhibition reactive oxygen species (ROS) Reactive oxygen species
We found that multiple studies reported significantly elevated NQO1 mRNA levels, ranging from three to tenfold, in pancreatic cancer compared to normal pancreatic tissue from a considerable number of patients (Fig. 1A–E)
We found that MIA PaCa-2, Capan-2 and AsPC-1 show significantly higher NQO1 protein levels compared to hTERT-HPNE (Fig. 1F)

Summary

Introduction

Abbreviations DIC Dicoumarol β-lap β-Lapachone NAC N-Acetylcysteine amide NQO1 NAD(P)H:quinone oxidoreductase 1 PARP1 Poly(ADP-ribose) polymerase 1 PARPi PARP inhibition ROS Reactive oxygen species. Elevated expression of NAD(P)H:Quinone Oxidoreductase 1 (NQO1) is frequent in pancreatic cancer, allowing for tumor-selective targeting, and NQO1-bioactivatable compounds have been shown to be highly effective. NQO1 is a flavoprotein that functions as a homodimer, and each monomer that is bound to FAD catalyzes an obligatory two-electron reduction of a wide variety of quinones to their hydroquinone forms at the expense of cellular cofactors NADH or N ADPH7,8. These hydroquinone forms are generally very unstable, spontaneously react with oxygen, and are converted back to parent quinones. Dose-limiting anemia and methemoglobinemia remain the major challenges with β-lap as a monotherapy or in combination with other a gents[14,15,16]

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