An NQO1- and PARP-1-mediated cell death pathway induced in non-small-cell lung cancer cells by β-lapachone

Abstract

Lung cancer is the number one cause of cancer-related deaths in the world. Patients treated with current chemotherapies for non-smallcell lung cancers (NSCLCs) have a survival rate of Ϸ15% after 5 years. Novel approaches are needed to treat this disease. We show elevated NAD(P)H:quinone oxidoreductase-1 (NQO1) levels in tumors from NSCLC patients. ␤-Lapachone, an effective chemotherapeutic and radiosensitizing agent, selectively killed NSCLC cells that expressed high levels of NQO1. Isogenic H596 NSCLC cells that lacked or expressed NQO1 along with A549 NSCLC cells treated with or without dicoumarol, were used to elucidate the mechanism of action and optimal therapeutic window of ␤-lapachone. NSCLC cells were killed in an NQO1-dependent manner by ␤-lapachone (LD 50, Ϸ4 M) with a minimum 2-h exposure. Kinetically, ␤-lapachone-induced cell death was characterized by the following: (i) dramatic reactive oxygen species (ROS) formation, eliciting extensive DNA damage; (ii) hyperactivation of poly(ADP-ribose)polymerase-1 (PARP-1); (iii) depletion of NAD ؉ /ATP levels; and (iv) proteolytic cleavage of p53/PARP-1, indicating -calpain activation and apoptosis. ␤-Lapachone-induced PARP-1 hyperactivation, nucleotide depletion, and apoptosis were blocked by 3-aminobenzamide, a PARP-1 inhibitor, and 1,2-bis(2-aminophenoxy)ethane-N,N,N,N-tetraacetic acid acetoxymethyl ester (BAPTA-AM), a Ca 2؉ chelator. NQO1 ؊ cells (H596, IMR-90) or dicoumarol-exposed NQO1 ؉ A549 cells were resistant (LD50, >40 M) to ROS formation and all cytotoxic effects of ␤-lapachone. Our data indicate that the most efficacious strategy using ␤-lapachone in chemotherapy was to deliver the drug in short pulses, greatly reducing cytotoxicity to NQO1 ؊ ''normal'' cells. ␤-Lapachone killed cells in a tumorselective manner and is indicated for use against NQO1 ؉ NSCLC cancers.DNA repair inhibitor ͉ non-small-cell lung cancer ͉ NQO1 ͉ apoptosis ͉ -calpain cell death

Transforming Growth Factor–β Regulates Mammary Carcinoma Cell Survival and Interaction with the Adjacent Microenvironment

“…However, our data now suggest that the apoptotic response to TGF-h signaling also plays a significant role in early mammary tumor suppression. The decrease in both typical and atypical PARP-1 cleavage products associated with the ThRII ( fl/fl);PY;WC tumor tissue suggests that both the extrinsic and intrinsic caspase-dependent and caspase-independent cell death pathways are impaired in the absence of TGF-h signaling (25). The inhibition of apoptosis is an important consideration with regard to clinical treatment of cancer involving radiation or chemotherapy (39,40).…”

“…3D). Interestingly, the presence of both typical and atypical PARP-1 cleavage products suggests that both caspase-dependent and caspase-independent pathways together contribute to the increased cell death associated with ThRII ( fl/fl);PY tumor tissues in vivo (25). TGF-B signaling in mammary carcinoma cells can regulate the adjacent fibrovascular stroma during tumor progression.…”

Metabolic interplay between glycolysis and mitochondrial oxidation: The reverse Warburg effect and its therapeutic implication

“…In cancer cells, the increased ROS production from metabolic disarrangement and rapid proliferation may induce an upregulation of antioxidant capacity, i.e., vulnerable redox equilibrium with high ROS production and elimination to maintain the ROS levels below the threshold for cell death [196,197] . Thus, cancer cells would be more vulnerable to increased oxidative stress induced by exogenous ROS enhancers that directly or indirectly suppress the antioxidant system [198][199][200][201] . These characteristics may provide a biochemical basis for a combination treatment of glycolytic inhibitors and ROS enhancers.…”

Novel Redox-Responsive Amphiphilic Copolymer Micelles for Drug Delivery: Synthesis and Characterization

“…The reduction of the QPA subunits associated with synthetic materials has been demonstrated by the adoption of the simulated redox states not only with chemical agents such as dithionite and borohydride, but also with reductases such as DT-diaphorase (NAD(P)H:quinone oxidoreductase (NQO1), EC 1.6.99.2) (14,15). It is interesting to note that DT-diaphorase, a two-electron reductase, is highly expressed in several cancerous tissues (16,17). Tumors such as non-small cell lung cancer and pancreatic cancers have shown to express high levels of DT-diaphorase relative to normal tissue, as much as a 20-fold increase (18).…”