An NQO1 Substrate with Potent Antitumor Activity That Selectively Kills by PARP1-Induced Programmed Necrosis

Abstract

Agents, such as β-lapachone, that target the redox enzyme, NAD(P)H:quinone oxidoreductase 1 (NQO1), to induce programmed necrosis in solid tumors have shown great promise, but more potent tumor-selective compounds are needed. Here, we report that deoxynyboquinone kills a wide spectrum of cancer cells in an NQO1-dependent manner with greater potency than β-lapachone. Deoxynyboquinone lethality relies on NQO1-dependent futile redox cycling that consumes oxygen and generates extensive reactive oxygen species (ROS). Elevated ROS levels cause extensive DNA lesions, PARP1 hyperactivation, and severe NAD+/ATP depletion that stimulate Ca2+–dependent programmed necrosis, unique to this new class of NQO1 "bioactivated" drugs. Short-term exposure of NQO1+ cells to deoxynyboquinone was sufficient to trigger cell death, although genetically matched NQO1− cells were unaffected. Moreover, siRNA-mediated NQO1 or PARP1 knockdown spared NQO1+ cells from short-term lethality. Pretreatment of cells with BAPTA-AM (a cytosolic Ca2+ chelator) or catalase (enzymatic H2O2 scavenger) was sufficient to rescue deoxynyboquinone-induced lethality, as noted with β-lapachone. Investigations in vivo showed equivalent antitumor efficacy of deoxynyboquinone to β-lapachone, but at a 6-fold greater potency. PARP1 hyperactivation and dramatic ATP loss were noted in the tumor, but not in the associated normal lung tissue. Our findings offer preclinical proof-of-concept for deoxynyboquinone as a potent chemotherapeutic agent for treatment of a wide spectrum of therapeutically challenging solid tumors, such as pancreatic and lung cancers.

Combinative effects of β-Lapachone and APO866 on pancreatic cancer cell death through reactive oxygen species production and PARP-1 activation

“…Various cell death mechanisms involved in antitumor activities of BL or APO866 have been reported including activation of caspase [10,50e53], calpain [47,54,55] and increase of calcium [28,56]. None of these events seem to be involved in BL plus APO866-induced cell death.…”

“…NQO1 metabolizes BL to a highly reactive unstable hydroquinone that is then oxidized back to semiquinone or quinone. These redox reactions generate elevated level of ROS (superoxide anions and hydrogen peroxide) production that result in DNA damage, PARP-1 activation and ultimately leading to NAD, ATP depletion and cell death [28,30]. Therefore, BL selectively kills cancer cells expressing NQO1.…”

Leveraging an NQO1 bioactivatable drug for tumor-selective use of poly (ADP-ribose) polymerase (PARP) inhibitors

“…NQO1 − MDA-MB-231 cells were inherently resistant to β-lap, with or without Rucaparib ( Figure 4H). All Rucaparib doses were nontoxic ( Figure S4C), and NQO1 levels in genetically matched NQO1-expressing ordeficient H596, MiaPaCa2, or MDA-MB-231 cells were described (Bey et al, 2007;Huang et al, 2012;Li et al, 2011). Synergy between PARP inhibitors and β-lap was noted across cell lines and independent of oncogenic driver mutations (Figure 2 and Figure S4D).…”

“…quinones that include β-lapachone (β-lap, ARQ761 in clinical form) and deoxynyboquinone (Huang et al, 2012). NQO1 catalyzes the two-electron oxidoreduction of β-lap to generate an unstable hydroquinone that spontaneously reacts in a two-step back-reaction with oxygen to regenerate the original compound (Bey et al, 2007).…”

Deoxynyboquinones as NQO1-Activated Cancer Therapeutics

“…49 The final and most substantiated NQO1-dependent modeof-action for anticancer agents is through redox cycling. 9,46,50 Upon reduction of an appropriate quinone by NQO1, the respective hydroquinones rapidly react with molecular oxygen in the cell to give two moles of superoxide and regenerate the quinone ( Figure 1). Because these compounds rapidly and catalytically generate large quantities of toxic ROS only in NQO1-expressing cells, they have considerable potential as anticancer agents.…”