Phase 1 study of ARQ 761, a β-lapachone analogue that promotes NQO1-mediated programmed cancer cell necrosis

β-Lapachone, an NQO1 bioactivatable drug, prevents lung tumorigenesis in mice

Lung cancer is one of the most lethal cancers with high incidence worldwide. The prevention of lung cancer is of great significance to reducing the social harm caused by this disease. An in-depth understanding of the molecular changes underlying precancerous lesions is essential for the targeted chemoprevention against lung cancer. Here, we discovered an increased NQO1 level over time within pulmonary premalignant lesions in both the KrasG12D-driven and nicotine-derived nitrosamine ketone (NNK)-induced mouse models of lung cancer, as well as in KrasG12D-driven and NNK-induced malignant transformed human bronchial epithelial cells (BEAS-2B and 16HBE). This suggests a potential correlation between the NQO1 expression and lung carcinogenesis. Based on this finding, we utilized β-Lapachone (β-Lap), an NQO1 bioactivatable drug, to suppress lung tumorigenesis. In this study, the efficacy and safety of low-dose β-Lap were demonstrated in preventing lung tumorigenesis in vivo. In conclusion, our study suggests that long-term consumption of low-dose β-Lap could potentially be an effective therapeutic strategy for the prevention of lung premalignant lesions. However, further studies and clinical trials are necessary to validate our findings, determine the safety of long-term β-Lap usage in humans, and promote the use of β-Lap in high-risk populations.

MTH1 inhibition synergizes with ROS-inducing agents to trigger cervical cancer cells undergoing parthanatos

Cervical cancer cells possess high levels of reactive oxygen species (ROS); thus, increasing oxidative stress above the toxicity threshold to induce cell death is a promising chemotherapeutic strategy. However, the underlying mechanisms of cell death are elusive, and efficacy and toxicity issues remain. Within DNA, 8-oxo-7,8-dihydroguanine (8-oxoG) is the most frequent base lesion repaired by 8-oxoguanine glycosylase 1 (OGG1)-initiated base excision repair. Cancer cells also express high levels of MutT homolog 1 (MTH1), which prevents DNA replication-induced incorporation of 8-oxoG into the genome by hydrolyzing 8-oxo-7,8-dihydro-2'-deoxyguanosine 5'-triphosphate (8-oxo-dGTP). Here, we revealed that ROS-inducing agents triggered cervical cancer to undergo parthanatos, which was mainly induced by massive DNA strand breaks resulting from overwhelming 8-oxoG excision by OGG1. Furthermore, the MTH1 inhibitor synergized with a relatively low dose of ROS-inducing agents by enhancing 8-oxoG loading in the DNA. In vivo, this drug combination suppressed the growth of tumor xenografts, and this inhibitory effect was significantly decreased in the absence of OGG1. Hence, the present study highlights the roles of base repair enzymes in cell death induction and suggests that the combination of lower doses of ROS-inducing agents with MTH1 inhibitors may be a more selective and safer strategy for cervical cancer chemotherapy.

IB-DNQ and Rucaparib dual treatment alters cell cycle regulation and DNA repair in triple negative breast cancer cells

Background

Triple negative breast cancer (TNBC), characterized by the lack of three canonical receptors, is unresponsive to commonly used hormonal therapies. One potential TNBC-specific therapeutic target is NQO1, as it is highly expressed in many TNBC patients and lowly expressed in non-cancer tissues. DNA damage induced by NQO1 bioactivatable drugs in combination with Rucaparib-mediated inhibition of PARP1-dependent DNA repair synergistically induces cell death.

Methods

To gain a better understanding of the mechanisms behind this synergistic effect, we used global proteomics, phosphoproteomics, and thermal proteome profiling to analyze changes in protein abundance, phosphorylation and protein thermal stability.

Results

Very few protein abundance changes resulted from single or dual agent treatment; however, protein phosphorylation and thermal stability were impacted. Histone H2AX was among several proteins identified to have increased phosphorylation when cells were treated with the combination of IB-DNQ and Rucaparib, validating that the drugs induced persistent DNA damage. Thermal proteome profiling revealed destabilization of H2AX following combination treatment, potentially a result of the increase in phosphorylation. Kinase substrate enrichment analysis predicted altered activity for kinases involved in DNA repair and cell cycle following dual agent treatment. Further biophysical analysis of these two processes revealed alterations in SWI/SNF complex association and tubulin / p53 interactions.

Conclusions

Our findings that the drugs target DNA repair and cell cycle regulation, canonical cancer treatment targets, in a way that is dependent on increased expression of a protein selectively found to be upregulated in cancers without impacting protein abundance illustrate that multi-omics methodologies are important to gain a deeper understanding of the mechanisms behind treatment induced cancer cell death.

Unlocking the effective alliance of β-lapachone and hydroxytyrosol against triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) is characterised by its aggressiveness and resistance to chemotherapy, demanding the development of effective strategies against its unique characteristics. Derived from lapacho tree bark, β-lapachone (β-LP) selectively targets cancer cells with elevated levels of the detoxifying enzyme NQO1. Hydroxytyrosol (HT) is a phenolic compound derived from olive trees with important anticancer properties that include the inhibition of cancer stem cells (CSCs) and metastatic features in TNBC, as well as relevant antioxidant activities by mechanisms such as the induction of NQO1. We aimed to study whether these compounds could have synergistic anticancer activity in TNBC cells and the possible role of NQO1. For this pourpose, we assessed the impact of β-LP (0.5 or 1.5 μM) and HT (50 and 100 μM) on five TNBC cell lines. We demonstrated that the combination of β-LP and HT exhibits anti-proliferative, pro-apoptotic, and cell cycle arrest effects in several TNBC cells, including docetaxel-resistant TNBC cells. Additionally, it effectively inhibits the self-renewal and clonogenicity of CSCs, modifying their aggressive phenotype. However, the notable impact of the β-LP-HT combination does not appear to be solely associated with the levels of the NQO1 protein and ROS. RNA-Seq analysis revealed that the combination's anticancer activity is linked to a strong induction of endoplasmic reticulum stress and apoptosis through the unfolded protein response. In conclusion, in this study, we demonstrated how the combination of β-LP and HT could offer an affordable, safe, and effective approach against TNBC.

β-Lapachone induces ferroptosis of colorectal cancer cells via NCOA4-mediated ferritinophagy by activating JNK pathway

β-Lapachone is a natural product that can promote ROS generation and ultimately triggers tumor cells death by inducing DNA damage. Recent studies have indicated that the targeting of ferroptosis or iron metabolism is a feasible strategy for treating cancer. In this study, bulk RNA-seq analysis suggested that β-Lapachone might induce ferroptosis in CRC cells. We further tested this hypothesis using a xenograft model of human colorectal cancer as an animal model and in SW620 and DLD-1 of CRC cell lines. Western blot was used to determine the key proteins of ferroptosis (SLC7A11, GPX4), autophagy (LC3B, P62, ATG7), ferritinophagy (NCOA4, FTH1, TFRC), and JNK pathway (p-JNK, JNK, p-c-Jun, c-Jun). The levels of MDA, GSH/GSSG, lipid ROS, and intracellular ferrous iron were determined after β-Lapachone treatment, and inhibitors of various pathways, including NAC, Ferrostatin-1, DFO, 3-MA, and SP600125 were utilized to explore the molecular mechanism underlying β-Lapachone-mediated ferroptosis. As the result, we identified that β-Lapachone inhibited cell proliferation and induced apoptosis, autophagy, and ROS generation. In addition, β-Lapachone induced ferroptosis as demonstrated by intra-cellular iron overload, increased levels of lipid ROS and MDA. Mechanistically, JNK signaling pathway was involved in β-Lapachone-induced xCT/GPX4-mediated ferroptosis and NCOA4-mediated ferritinophagy in CRC cells. In vivo experiments in nude mice demonstrated that β-Lapachone significantly inhibited CRC growth and induced ferroptosis and NCOA4-mediated ferritinophagy. These findings not only identify a novel role for β-Lapachone in ferroptosis but also indicate that β-Lapachone may be a valuable candidate for the research and development of anti-cancer therapeutic agents.

Augmented Concentration of Isopentyl-Deoxynyboquinone in Tumors Selectively Kills NAD(P)H Quinone Oxidoreductase 1-Positive Cancer Cells through Programmed Necrotic and Apoptotic Mechanisms

Lung and breast cancers rank as two of the most common and lethal tumors, accounting for a substantial number of cancer-related deaths worldwide. While the past two decades have witnessed promising progress in tumor therapy, developing targeted tumor therapies continues to pose a significant challenge. NAD(P)H quinone oxidoreductase 1 (NQO1), a two-electron reductase, has been reported as a promising therapeutic target across various solid tumors. β-Lapachone (β-Lap) and deoxynyboquinone (DNQ) are two NQO1 bioactivatable drugs that have demonstrated potent antitumor effects. However, their curative efficacy has been constrained by adverse effects and moderate lethality. To enhance the curative potential of NQO1 bioactivatable drugs, we developed a novel DNQ derivative termed isopentyl-deoxynyboquinone (IP-DNQ). Our study revealed that IP-DNQ treatment significantly increased reactive oxygen species generation, leading to double-strand break (DSB) formation, PARP1 hyperactivation, and catastrophic energy loss. Notably, we discovered that this novel drug induced both apoptosis and programmed necrosis events, which makes it entirely distinct from other NQO1 bioactivatable drugs. Furthermore, IP-DNQ monotherapy demonstrated significant antitumor efficacy and extended mice survival in A549 orthotopic xenograft models. Lastly, we identified that in mice IP-DNQ levels were significantly elevated in the plasma and tumor compared with IB-DNQ levels. This study provides novel preclinical evidence supporting IP-DNQ efficacy in NQO1+ NSCLC and breast cancer cells.

Fighting drug-resistant lung cancer by induction of NAD(P)H:quinone oxidoreductase 1 (NQO1)-mediated ferroptosis

Drug resistance is a major challenge in cancer treatment. The substrates of NAD(P)H:quinone oxidoreductase 1 (NQO1) show a promising anticancer effect in clinical trials. We previously identified a natural NQO1 substrate 2-methoxy-6-acetyl-7-methyljuglone (MAM) with a potent anticancer effect. The present study was designed to explore the efficacy of MAM in fighting against drug-resistant non-small cell lung cancer (NSCLC). The anticancer effect of MAM was evaluated in cisplatin-resistant A549 and AZD9291-resistant H1975 cells. The interaction of MAM with NQO1 was measured by cellular thermal shift assay and drug affinity responsive target stability assay. The NQO1 activity and expression were measured using NQO1 recombinant protein, Western blotting, and immunofluorescence staining assay. The roles of NQO1 were examined by NQO1 inhibitor, small interfering RNA (siRNA), and short hairpin RNA (shRNA). The roles of reactive oxygen species (ROS), labile iron pool (LIP), and lipid peroxidation were determined. MAM induced significant cell death in drug-resistant cells with similar potency to that of parental cells, which were completely abolished by NQO1 inhibitor, NQO1 siRNA, and iron chelators. MAM activates and binds to NQO1, which triggers ROS generation, LIP increase, and lipid peroxidation. MAM significantly suppressed tumor growth in the tumor xenograft zebrafish model. These results showed that MAM induced ferroptosis by targeting NQO1 in drug-resistant NSCLC cells. Our findings provided a novel therapeutic strategy for fighting against drug resistance by induction of NQO1-mediated ferroptosis.

Enhanced Chemodynamic Therapy Mediated by a Tumor-Specific Catalyst in Synergy with Mitophagy Inhibition Improves the Efficacy for Endometrial Cancer

Chemodynamic therapy (CDT) relies on the tumor microenvironment (e.g., high H2 O2 level) responsive Fenton-like reactions to produce hydroxyl radicals (·OH) against tumors. However, endogenous H2 O2 is insufficient for effective chemodynamic responses. An NAD(P)H: quinone oxidoreductase 1 (NQO1)high catalase (CAT)low therapeutic window for the use of NQO1 bioactive drug β-lapachone (β-Lap) is first identified in endometrial cancer (EC). Accompanied by NADH depletion, NQO1 catalyzes β-Lap to produce excess H2 O2 and initiate oxidative stress, which selectively suppress NQO1high EC cell proliferation, induce DNA double-strand breaks, and promote apoptosis. Moreover, shRNA-mediated NQO1 knockdown or dicoumarol rescues NQO1high EC cells from β-Lap-induced cytotoxicity. Arginine-glycine-aspartic acid (RGD)-functionalized iron-based metal-organic frameworks (MOF(Fe)) further promote the conversion of the accumulated H2 O2 into highly oxidative ·OH, which in turn, exacerbates the oxidative damage to RGD-positive target cells. Furthermore, mitophagy inhibition by Mdivi-1 blocks a powerful antioxidant defense approach, ultimately ensuring the anti-tumor efficacy of stepwise-amplified reactive oxygen species signals. The tumor growth inhibition rate (TGI) is about 85.92%. However, the TGI of MOF(Fe)-based synergistic antitumor therapy decreases to only 50.46% in NQO1-deficient KLE tumors. Tumor-specific chemotherapy and CDT-triggered therapeutic modality present unprecedented therapeutic benefits in treating NQO1high EC.

Systematic identification of anticancer drug targets reveals a nucleus-to-mitochondria ROS-sensing pathway

Multiple anticancer drugs have been proposed to cause cell death, in part, by increasing the steady-state levels of cellular reactive oxygen species (ROS). However, for most of these drugs, exactly how the resultant ROS function and are sensed is poorly understood. It remains unclear which proteins the ROS modify and their roles in drug sensitivity/resistance. To answer these questions, we examined 11 anticancer drugs with an integrated proteogenomic approach identifying not only many unique targets but also shared ones-including ribosomal components, suggesting common mechanisms by which drugs regulate translation. We focus on CHK1 that we find is a nuclear H2O2 sensor that launches a cellular program to dampen ROS. CHK1 phosphorylates the mitochondrial DNA-binding protein SSBP1 to prevent its mitochondrial localization, which in turn decreases nuclear H2O2. Our results reveal a druggable nucleus-to-mitochondria ROS-sensing pathway-required to resolve nuclear H2O2 accumulation and mediate resistance to platinum-based agents in ovarian cancers.

An Elusive Target: Inhibitors of JC Polyomavirus Infection and Their Development as Therapeutics for the Treatment of Progressive Multifocal Leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease caused by infection with JC Polyomavirus (JCPyV). Despite the identification of the disease and isolation of the causative pathogen over fifty years ago, no antiviral treatments or prophylactic vaccines exist. Disease onset is usually associated with immunosuppression, and current treatment guidelines are limited to restoring immune function. This review summarizes the drugs and small molecules that have been shown to inhibit JCPyV infection and spread. Paying attention to historical developments in the field, we discuss key steps of the virus lifecycle and antivirals known to inhibit each event. We review current obstacles in PML drug discovery, including the difficulties associated with compound penetrance into the central nervous system. We also summarize recent findings in our laboratory regarding the potent anti-JCPyV activity of a novel compound that antagonizes the virus-induced signaling events necessary to establish a productive infection. Understanding the current panel of antiviral compounds will help center the field for future drug discovery efforts.

Expanding Transition Metal-Mediated Bioorthogonal Decaging to Include C-C Bond Cleavage Reactions

The ability to control the activation of prodrugs by transition metals has been shown to have great potential for controlled drug release in cancer cells. However, the strategies developed so far promote the cleavage of C-O or C-N bonds, which limits the scope of drugs to only those that present amino or hydroxyl groups. Here, we report the decaging of an ortho-quinone prodrug, a propargylated β-lapachone derivative, through a palladium-mediated C-C bond cleavage. The reaction's kinetic and mechanistic behavior was studied under biological conditions along with computer modeling. The results indicate that palladium (II) is the active species for the depropargylation reaction, activating the triple bond for nucleophilic attack by a water molecule before the C-C bond cleavage takes place. Palladium iodide nanoparticles were found to efficiently trigger the C-C bond cleavage reaction under biocompatible conditions. In drug activation assays in cells, the protected analogue of β-lapachone was activated by nontoxic amounts of nanoparticles, which restored drug toxicity. The palladium-mediated ortho-quinone prodrug activation was further demonstrated in zebrafish tumor xenografts, which resulted in a significant anti-tumoral effect. This work expands the transition-metal-mediated bioorthogonal decaging toolbox to include cleavage of C-C bonds and payloads that were previously not accessible by conventional strategies.

The Role of NQO1 in Ovarian Cancer

Ovarian cancer is one of the most dangerous gynecologic malignancies showing a high fatality rate because of late diagnosis and relapse occurrence due to chemoresistance onset. Several researchers reported that oxidative stress plays a key role in ovarian cancer occurrence, growth and development. The NAD(P)H:quinone oxidoreductase 1 (NQO1) is an antioxidant enzyme that, using NADH or NADPH as substrates to reduce quinones to hydroquinones, avoids the formation of the highly reactive semiquinones, then protecting cells against oxidative stress. In this review, we report evidence from the literature describing the effect of NQO1 on ovarian cancer onset and progression.

Naphth[1,2-d]imidazoles Bioactive from β-Lapachone: Fluorescent Probes and Cytotoxic Agents to Cancer Cells

Theranostics combines therapeutic and imaging diagnostic techniques that are extremely dependent on the action of imaging agent, transporter of therapeutic molecules, and specific target ligand, in which fluorescent probes can act as diagnostic agents. In particular, naphthoimidazoles are potential bioactive heterocycle compounds to be used in several biomedical applications. With this aim, a group of seven naphth[1,2-d]imidazole compounds were synthesized from β-lapachone. Their optical properties and their cytotoxic activity against cancer cells and their compounds were evaluated and confirmed promising values for molar absorptivity coefficients (on the order of 103 to 104), intense fluorescence emissions in the blue region, and large Stokes shifts (20–103 nm). Furthermore, the probes were also selective for analyzed cancer cells (leukemic cells (HL-60). The naphth[1,2-d]imidazoles showed IC50 between 8.71 and 29.92 μM against HL-60 cells. For HCT-116 cells, values for IC50 between 21.12 and 62.11 μM were observed. The selective cytotoxicity towards cancer cells and the fluorescence of the synthesized naphth[1,2-d]imidazoles are promising responses that make possible the application of these components in antitumor theranostic systems.

Single-Cell Kinetic Modeling of β-Lapachone Metabolism in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) cells are highly heterogeneous in their metabolism and typically experience elevated reactive oxygen species (ROS) levels such as superoxide and hydrogen peroxide (H2O2) in the tumor microenvironment. Tumor cells survive under these chronic oxidative conditions by upregulating antioxidant systems. To investigate the heterogeneity of cellular responses to chemotherapeutic H2O2 generation in tumor and healthy tissue, we leveraged single-cell RNA-sequencing (scRNA-seq) data to perform redox systems-level simulations of quinone-cycling β-lapachone treatment as a source of NQO1-dependent rapid superoxide and hydrogen peroxide (H2O2) production. Transcriptomic data from 10 HNSCC patient tumors was used to populate over 4000 single-cell antioxidant enzymatic network models of drug metabolism. The simulations reflected significant systems-level differences between the redox states of healthy and cancer cells, demonstrating in some patient samples a targetable cancer cell population or in others statistically indistinguishable effects between non-malignant and malignant cells. Subsequent multivariate analyses between healthy and malignant cellular models pointed to distinct contributors of redox responses between these phenotypes. This model framework provides a mechanistic basis for explaining mixed outcomes of NAD(P)H:quinone oxidoreductase 1 (NQO1)-bioactivatable therapeutics despite the tumor specificity of these drugs as defined by NQO1/catalase expression and highlights the role of alternate antioxidant components in dictating drug-induced oxidative stress.

Tumor killing by a dietary curcumin mono-carbonyl analog that works as a selective ROS generator via TrxR inhibition

In comparison with normal cells, cancer cells feature intrinsic oxidative stress, thereby being more vulnerable to further production of reactive oxygen species (ROS) by pro-oxidative anticancer agents (PAAs). However, PAAs also inevitably generate ROS in normal cells, resulting in their narrow therapeutic window and toxic side effects that greatly limit their clinical application. To develop PAAs that generate ROS selectively in cancer cells over in normal cells, we rationally designed three series of 21 dietary curcumin 5-carbon mono-carbonyl analogs differentiated by either placement of the cyclohexanone, piperidone, and methylpiperidone linkers, or introduction of electron-withdrawing trifluoromethyl and electron-donating methoxyl groups on its two aromatic rings in the ortho, meta, or para position to the linkers. From the designed molecules, 2c, characterized of the presence of the meta-CF₃-substituted mode and the piperidone linker, was identified as a potent selective ROS-generating agent, allowing its ability to kill selectively human non-small cell lung cancer NCI-H460 (IC₅₀ = 0.44 μM) over human normal lung MRC-5 cells with a selectivity index of 32.0. Additionally, it was more potent and selective than the conventional chemotherapeutic agents (5-fluorouracil and camptothecin) did. Mechanistical investigation reveals that by means of its Michael acceptor unit and structure characteristics as described above, 2c could covalently modify the Sec-498 residue of intracellular thioredoxin reductase (TrxR) to generate ROS selectively, resulting in ROS-dependent apoptosis and ferroptosis of NCI-H460 cells. Noticeably, 2c inhibited significantly the growth of NCI-H460 cell xenograft tumor in nude mice without obvious toxicity to liver and kidney. Together, this work highlights a practical strategy of targeting TrxR overexpressed in cancer cells to develop PAAs capable of generating ROS selectively, as evidenced by the example of 2c.

Identification of chemotherapy targets reveals a nucleus-to-mitochondria ROS sensing pathway

Multiple chemotherapies are proposed to cause cell death in part by increasing the steady-state levels of cellular reactive oxygen species (ROS). However, for most of these drugs exactly how the resultant ROS function and are sensed is poorly understood. In particular, it's unclear which proteins the ROS modify and their roles in chemotherapy sensitivity/resistance. To answer these questions, we examined 11 chemotherapies with an integrated proteogenomic approach identifying many unique targets for these drugs but also shared ones including ribosomal components, suggesting one mechanism by which chemotherapies regulate translation. We focus on CHK1 which we find is a nuclear H ₂ O ₂ sensor that promotes an anti-ROS cellular program. CHK1 acts by phosphorylating the mitochondrial-DNA binding protein SSBP1, preventing its mitochondrial localization, which in turn decreases nuclear H ₂ O ₂ . Our results reveal a druggable nucleus-to-mitochondria ROS sensing pathway required to resolve nuclear H ₂ O ₂ accumulation, which mediates resistance to platinum-based chemotherapies in ovarian cancers.

Natural and synthetic compounds for glioma treatment based on ROS-mediated strategy

Glioma is the most frequent and most malignant tumor of the central nervous system (CNS)，accounting for about 50% of all CNS tumor and approximately 80% of the malignant primary tumors in the CNS. Patients with glioma benefit from surgical resection, chemo- and radio-therapy. However these therapeutical strategies do not significantly improve the prognosis, nor increase survival rates owing to restricted drug contribution in the CNS and to the malignant characteristics of glioma. Reactive oxygen species (ROS) are important oxygen-containing molecules that regulate tumorigenesis and tumor progression. When ROS accumulates to cytotoxic levels, this can lead to anti-tumor effects. Multiple chemicals used as therapeutic strategies are based on this mechanism. They regulate intracellular ROS levels directly or indirectly, resulting in the inability of glioma cells to adapt to the damage induced by these substances. In the current review, we summarize the natural products, synthetic compounds and interdisciplinary techniques used for the treatment of glioma. Their possible molecular mechanisms are also presented. Some of them are also used as sensitizers: they modulate ROS levels to improve the outcomes of chemo- and radio-therapy. In addition, we summarize some new targets upstream or downstream of ROS to provide ideas for developing new anti-glioma therapies.

Evaluation of β-lapachone-methyl-β-cyclodextrin inclusion complex prepared by spray drying and its application against different developmental stages of Schistosoma mansoni in murine model

BACKGROUND

β-lapachone (β-lap) is a naphthoquinone widely found in species of vegetables. However, its poor aqueous solubility limits its systemic administration and clinical applications in vivo. To overcome this limitation, several studies have been carried out in order to investigate techniques that can enhance the solubility and dissolution rate of β-lap, such as the use of inclusion complexes with cyclodextrin.

PURPOSE

To evaluate the in vivo effect of β-lap complexed in methyl-β-cyclodextrin (MβCD) on the evolutionary stages of Schistosoma mansoni in a murine model.

METHODS

The development and characterization of the physicochemical properties of the inclusion complex of β-lap in β-lap:MβCD was prepared by solubility and dissolution tests, FTIR, DSC, X-RD and SEM. The mice were infected and subsequently treated with β-lap:MβCD orally with 50 mg/kg/day and 100 mg/kg/day for 5 consecutive days, starting therapy on the 1^st (skin schistosomula), 14^th (pulmonary schistosomula), 28^th (young worms) and 45^th (adult worms) days after infection. Control groups were also formed; one infected untreated, treated with MβCD, and the other treated with PZQ.

RESULTS

The loss of the crystalline form of β-lap in the β-lap:MβCD complex obtained by spray drying was proven through physical-chemical characterization analyses. β-lap:MβCD caused reduction in the number of worms of the 33.56%, 35.7%, 35.45% and 36.45%, when the dose was at 50 mg/kg, and 65.00%, 60.34%, 52.72% and 65.01%, in the dose 100 mg/kg; when treatment was started in the 1^st, 14^th, 28^th and 45^th days after infection, respectively. It was also possible to observe a significant reduction in the number of immature eggs and an increase in the number of ripe and dead eggs and, consequently, a reduction in the damage caused by the egg antigens to the host tissue, where we attributed the reduction in the average diameter of the granulomas to the β-lap.

CONCLUSION

The dissolved content of β-lap:MβCD by spray drying reached almost 100%, serving for future formulations and delineation of the mechanisms of action of β-lap against S. mansoni.

It Takes Two to Tango, Part II: Synthesis of A-Ring Functionalised Quinones Containing Two Redox-Active Centres with Antitumour Activities

In 2021, our research group published the prominent anticancer activity achieved through the successful combination of two redox centres (ortho-quinone/para-quinone or quinone/selenium-containing triazole) through a copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The combination of two naphthoquinoidal substrates towards a synergetic product was indicated, but not fully explored. Herein, we report the synthesis of 15 new quinone-based derivatives prepared from click chemistry reactions and their subsequent evaluation against nine cancer cell lines and the murine fibroblast line L929. Our strategy was based on the modification of the A-ring of para-naphthoquinones and subsequent conjugation with different ortho-quinoidal moieties. As anticipated, our study identified several compounds with IC₅₀ values below 0.5 µM in tumour cell lines. Some of the compounds described here also exhibited an excellent selectivity index and low cytotoxicity on L929, the control cell line. The antitumour evaluation of the compounds separately and in their conjugated form proved that the activity is strongly enhanced in the derivatives containing two redox centres. Thus, our study confirms the efficiency of using A-ring functionalized para-quinones coupled with ortho-quinones to obtain a diverse range of two redox centre compounds with potential applications against cancer cell lines. Here as well, it literally takes two for an efficient tango!

The Role of 8-oxoG Repair Systems in Tumorigenesis and Cancer Therapy

Tumorigenesis is highly correlated with the accumulation of mutations. The abundant and extensive DNA oxidation product, 8-Oxoguanine (8-oxoG), can cause mutations if it is not repaired by 8-oxoG repair systems. Therefore, the accumulation of 8-oxoG plays an essential role in tumorigenesis. To avoid the accumulation of 8-oxoG in the genome, base excision repair (BER), initiated by 8-oxoguanine DNA glycosylase1 (OGG1), is responsible for the removal of genomic 8-oxoG. It has been proven that 8-oxoG levels are significantly elevated in cancer cells compared with cells of normal tissues, and the induction of DNA damage by some antitumor drugs involves direct or indirect interference with BER, especially through inducing the production and accumulation of reactive oxygen species (ROS), which can lead to tumor cell death. In addition, the absence of the core components of BER can result in embryonic or early post-natal lethality in mice. Therefore, targeting 8-oxoG repair systems with inhibitors is a promising avenue for tumor therapy. In this study, we summarize the impact of 8-oxoG accumulation on tumorigenesis and the current status of cancer therapy approaches exploiting 8-oxoG repair enzyme targeting, as well as possible synergistic lethality strategies involving exogenous ROS-inducing agents.

Albumin binding revitalizes NQO1 bioactivatable drugs as novel therapeutics for pancreatic cancer

NAD(P)H:quinone oxidoreductase 1 (NQO1) is an enzyme significantly overexpressed in pancreatic ductal adenocarcinoma (PDAC) tumors compared to the associated normal tissues. NQO1 bioactivatable drugs, such as β-lapachone (β-lap), can be catalyzed to generate reactive oxygen species (ROS) for direct tumor killing. However, the extremely narrow therapeutic window caused by methemoglobinemia and hemolytic anemia severely restricts its further clinical translation despite considerable efforts in the past 20 years. Previously, we demonstrated that albumin could be utilized to deliver cytotoxic drugs selectively into KRAS-mutant PDAC with a much expanded therapeutic window due to KRAS-enhanced macropinocytosis and reduced neonatal Fc receptor (FcRn) expression in PDAC. Herein, we analyzed the expression patterns of albumin and FcRn across major organs in LSL-Kras^G12D/+;LSL-Trp53^R172H/+;Pdx-1-Cre (KPC) mice. The tumors were the predominant tissues with both elevated albumin and reduced FcRn expression, thus making them an ideal target for albumin-based drug delivery. Quantitative proteomics analysis of tissue samples from 5 human PDAC patients further confirmed the elevated albumin/FcRn ratio. Given such a compelling biological rationale, we designed a nanoparticle albumin-bound prodrug of β-lap, nab-(pro-β-lap), to achieve PDAC targeted delivery and expand the therapeutic window of β-lap. We found that nab-(pro-β-lap) uptake was profoundly enhanced by KRAS mutation. Compared to the solution formulation of the parent drug β-lap, nab-(pro-β-lap) showed enhanced safety due to much lower rates of methemoglobinemia and hemolytic anemia, which was confirmed both in vitro and in vivo. Furthermore, nab-(pro-β-lap) significantly inhibited tumor growth in subcutaneously implanted KPC xenografts and enhanced the pharmacodynamic endpoints (e.g., PARP1 hyperactivation, γ-H₂AX). Thus, nab-(pro-β-lap), with improved safety and antitumor efficacy, offers a drug delivery strategy with translational viability for β-lap in pancreatic cancer therapy.

A CRISPR screen identifies redox vulnerabilities for KEAP1/NRF2 mutant non-small cell lung cancer

The redox regulator NRF2 is hyperactivated in a large percentage of non-small cell lung cancer (NSCLC) cases, which is associated with chemotherapy and radiation resistance. To identify redox vulnerabilities for KEAP1/NRF2 mutant NSCLC, we conducted a CRISPR-Cas9-based negative selection screen for antioxidant enzyme genes whose loss sensitized cells to sub-lethal concentrations of the superoxide (O2•-) -generating drug β-Lapachone. While our screen identified expected hits in the pentose phosphate pathway, the thioredoxin-dependent antioxidant system, and glutathione reductase, we also identified the mitochondrial superoxide dismutase 2 (SOD2) as one of the top hits. Surprisingly, β-Lapachone did not generate mitochondrial O2•- but rather SOD2 loss enhanced the efficacy of β-Lapachone due to loss of iron-sulfur protein function, loss of mitochondrial ATP maintenance and deficient NADPH production. Importantly, inhibition of mitochondrial electron transport activity sensitized cells to β-Lapachone, demonstrating that these effects may be translated to increase ROS sensitivity therapeutically.

Synergistic Effect of β-Lapachone and Aminooxyacetic Acid on Central Metabolism in Breast Cancer

The compound β-lapachone, a naturally derived naphthoquinone, has been utilized as a potent medicinal nutrient to improve health. Over the last twelve years, numerous reports have demonstrated distinct associations of β-lapachone and NAD(P)H: quinone oxidoreductase 1 (NQO1) protein in the amelioration of various diseases. Comprehensive research of NQO1 bioactivity has clearly confirmed the tumoricidal effects of β-lapachone action through NAD+-keresis, in which severe DNA damage from reactive oxygen species (ROS) production triggers a poly-ADP-ribose polymerase-I (PARP1) hyperactivation cascade, culminating in NAD+/ATP depletion. Here, we report a novel combination strategy with aminooxyacetic acid (AOA), an aspartate aminotransferase inhibitor that blocks the malate-aspartate shuttle (MAS) and synergistically enhances the efficacy of β-lapachone metabolic perturbation in NQO1+ breast cancer. We evaluated metabolic turnover in MDA-MB-231 NQO1+, MDA-MB-231 NQO1-, MDA-MB-468, and T47D cancer cells by measuring the isotopic labeling of metabolites from a [U-13C]glucose tracer. We show that β-lapachone treatment significantly hampers lactate secretion by ~85% in NQO1+ cells. Our data demonstrate that combinatorial treatment decreases citrate, glutamate, and succinate enrichment by ~14%, ~50%, and ~65%, respectively. Differences in citrate, glutamate, and succinate fractional enrichments indicate synergistic effects on central metabolism based on the coefficient of drug interaction. Metabolic modeling suggests that increased glutamine anaplerosis is protective in the case of MAS inhibition.

Controlled masking and targeted release of redox-cycling ortho-quinones via a C-C bond-cleaving 1,6-elimination

Natural products that contain ortho-quinones show great potential as anticancer agents but have been largely discarded from clinical development because their redox-cycling behaviour results in general systemic toxicity. Here we report conjugation of ortho-quinones to a carrier, which simultaneously masks their underlying redox activity. C-benzylation at a quinone carbonyl forms a redox-inactive benzyl ketol. Upon a specific enzymatic trigger, an acid-promoted, self-immolative C-C bond-cleaving 1,6-elimination mechanism releases the redox-active hydroquinone inside cells. By using a 5-lipoxygenase modulator, β-lapachone, we created cathepsin-B-cleavable quinone prodrugs. We applied the strategy for intracellular release of β-lapachone upon antibody-mediated delivery. Conjugation of protected β-lapachone to Gem-IgG1 antibodies, which contain the variable region of gemtuzumab, results in homogeneous, systemically non-toxic and conditionally stable CD33+-specific antibody-drug conjugates with in vivo efficacy against a xenograft murine model of acute myeloid leukaemia. This protection strategy could allow the use of previously overlooked natural products as anticancer agents, thus extending the range of drugs available for next-generation targeted therapeutics.

Bladder cancer selective chemotherapy with potent NQO1 substrate co-loaded prodrug nanoparticles

Currently, clinical intravesical instillation chemotherapy has been greatly compromised by the toxicological and physiological factors. New formulations that can specifically and efficiently kill bladder cancer cells are in urgent need to overcome the low residence efficiency and dose limiting toxicity of current ones. The combination of mucoadhesive nanocarriers and cancer cell selective prodrugs can to great extent address these limitations. However, the insignificant endogenous stimulus difference between cancer cells and normal cells in most cases and the high local drug concentration make it essential to develop new drugs with broader selectivity-window. Herein, based on the statistically different NQO1 expression between cancerous and normal bladder tissues, the reactive oxygen species (ROS) activatable epirubicin prodrug and highly potent NQO1 substrate, KP372-1, was co-delivered using a GSH-responsive mucoadhesive nanocarrier. After endocytosis, epirubicin could be promptly activated by the NQO1-dependent ROS production caused by KP372-1, thus specifically inhibiting the proliferation of bladder cancer cells. Since KP372-1 is much more potent than some commonly used NQO1 substrates, for example, β-lapachone, the cascade drug activation could occur under much lower drug concentration, thus greatly lowering the toxicity in normal cells and broadening the selectivity-window during intravesical bladder cancer chemotherapy.

Inhibition of thioredoxin reductase by natural anticancer candidate β-lapachone accounts for triggering redox activation-mediated HL-60 cell apoptosis

β-Lapachone as a natural novel anticancer candidate is under clinical trials. Previous studies suggested that β-lapachone works by redox activation to ablate cancer cells. However, it is still unclear whether thioredoxin reductase (TrxR), one of the key redox catalytic enzymes in cells, plays a role in the pharmacological effects of β-lapachone. Herein, we present that β-lapachone kills human promyelocytic leukemia HL-60 cells with preference over other cancer cells and normal cells. The follow-up studies demonstrate that β-lapachone induces the HL-60 cell apoptosis through inhibition of TrxR and further elevation of oxidative stress. Overexpression of the TrxR alleviates the efficiency of β-lapachone while knockdown of the enzyme increases the β-lapachone cytotoxicity, scientifically underpinning the correlation of the observed biological behaviors of β-lapachone to TrxR inhibition. The disclosure of the novel action mechanism of β-lapachone sheds light on understanding its capacity in interfering with cellular redox signaling and supports β-lapachone as an anticancer drug candidate.

Metabolic response to radiation therapy in cancer

Tumor metabolism has emerged as a hallmark of cancer and is involved in carcinogenesis and tumor growth. Reprogramming of tumor metabolism is necessary for cancer cells to sustain high proliferation rates and enhanced demands for nutrients. Recent studies suggest that metabolic plasticity in cancer cells can decrease the efficacy of anticancer therapies by enhancing antioxidant defenses and DNA repair mechanisms. Studying radiation-induced metabolic changes will lead to a better understanding of radiation response mechanisms as well as the identification of new therapeutic targets, but there are few robust studies characterizing the metabolic changes induced by radiation therapy in cancer. In this review, we will highlight studies that provide information on the metabolic changes induced by radiation and oxidative stress in cancer cells and the associated underlying mechanisms.

X-ray repair cross-complementing protein 1 (XRCC1) loss promotes β-lapachone -induced apoptosis in pancreatic cancer cells

Background

β-lapachone (β-lap), the NQO1 bioactivatable drug, is thought to be a promising anticancer agent. However, the toxic side effects of β-lap limit the drug use, highlighting the need for a thorough understanding of β-lap’s mechanism of action. β-lap undergoes NQO1-dependent futile redox cycling, generating massive ROS and oxidative DNA lesions, leading to cell death. Thus, base excision repair (BER) pathway is an important resistance factor. XRCC1, a scaffolding component, plays a critical role in BER.

Methods

We knocked down XRCC1 expression by using pLVX-shXRCC1 in the MiaPaCa2 cells and BxPC3 cells and evaluated β-lap-induced DNA lesions by γH2AX foci formation and alkaline comet assay. The cell death induced by XRCC1 knockdown + β-lap treatment was analysed by relative survival, flow cytometry and Western blotting analysis.

Results

We found that knockdown of XRCC1 significantly increased β-lap-induced DNA double-strand breaks, comet tail lengths and cell death in PDA cells. Furthermore, we observed combining XRCC1 knockdown with β-lap treatment switched programmed necrosis with β-lap monotherapy to caspase-dependent apoptosis.

Conclusions

These results indicate that XRCC1 is involved in the repair of β-lap-induced DNA damage, and XRCC1 loss amplifies sensitivity to β-lap, suggesting targeting key components in BER pathways may have the potential to expand use and efficacy of β-lap for gene-based therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08979-y.

The modulation of SIRT1 and SIRT3 by natural compounds as a therapeutic target in doxorubicin-induced cardiotoxicity: A review

Doxorubicin (DOX) is a potent antitumor agent with a broad spectrum of activity; however, irreversible cardiotoxicity resulting from DOX treatment is a major issue that limits its therapeutic use. Sirtuins (SIRTs) play an essential role in several physiological and pathological processes including oxidative stress, apoptosis, and inflammation. It has been reported that SIRT1 and SIRT3 can act as a protective molecular against DOX-induced myocardial injury through targeting numerous signaling pathways. Several natural compounds (NCs), such as resveratrol, sesamin, and berberine, with antioxidative, anti-inflammation, and antiapoptotic effects were evaluated for their potential to suppress the cardiotoxicity induced by DOX via targeting SIRT1 and SIRT3. Numerous NCs exerted their therapeutic effects on DOX-mediated cardiac damage via targeting different signaling pathways, including SIRT1/LKB1/AMPK, SIRT1/PGC-1α, SIRT1/NLRP3, and SIRT3/FoxO. SIRT3 also ameliorates cardiotoxicity by enhancing mitochondrial fusion.

The possibility of low isomerization of β-lapachone in the human body

β-Lapachone has been reported to have anticancer and various other therapeutic effects, but is limited in clinical applications by its low bioavailability. pH-Dependent isomerization can be suggested as one plausible factor influencing its low bioavailability. Since it is known that β-lapachone is converted to its isomer, α-lapachone in hydrochloric acid (HCl) solution, isomerization in the human body may be driven by HCl in the gastric fluid. The purpose of this study was to evaluate the possibility of isomerization of β-lapachone in the human body. Chemical reactions were conducted using simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 7.5) at 37°C. β-Lapachone was observed in SGF at 37°C for 1 hour and SIF for 3 hours. In addition, biofluid analysis was performed on plasma samples 1 hour and 4 hours, and on urine sample 12 hours after oral administration of 100 mg MB12066, a synthetic β-lapachone, in healthy adult male. All samples were analyzed using liquid chromatography-tandem mass spectrometry. Only β-lapachone peaks existed in the spectra obtained from SGF and SIF. No isomerization of β-lapachone was observed in the analysis of any of the human samples. In the current study, the possibility of pH-dependent isomerization of β-lapachone in the human body was not confirmed.

Targeting NRF2 and Its Downstream Processes: Opportunities and Challenges

The transcription factor NRF2 coordinates the expression of a vast array of cytoprotective and metabolic genes in response to various stress inputs to restore cellular homeostasis. Transient activation of NRF2 in healthy tissues has been long recognized as a cellular defense mechanism and is critical to prevent cancer initiation by carcinogens. However, cancer cells frequently hijack the protective capability of NRF2 to sustain the redox balance and meet their metabolic requirements for proliferation. Further, aberrant activation of NRF2 in cancer cells confers resistance to commonly used chemotherapeutic agents and radiotherapy. During the last decade, many research groups have attempted to block NRF2 activity in tumors to counteract the survival and proliferative advantage of cancer cells and reverse resistance to treatment. In this review, we highlight the role of NRF2 in cancer progression and discuss the past and current approaches to disable NRF2 signaling in tumors. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Measuring NQO1 Bioactivation Using [2H7]Glucose

Treatment of cancers with β-lapachone causes NAD(P)H: quinone oxidoreductase 1 (NQO1) to generate an unstable hydroquinone that regenerates itself in a futile cycle while producing reactive oxygen species (ROS) in the form of superoxide and subsequently hydrogen peroxide. Rapid accumulation of ROS damages DNA, hyperactivates poly-ADP-ribose polymerase-I, causes massive depletion of NAD+/ATP, and hampers glycolysis. Cells overexpressing NQO1 subsequently die rapidly through an NAD+-keresis mechanism. Assessing changes in glycolytic rates caused by NQO1 bioactivation would provide a means of assessing treatment efficacy, potentially lowering the chemotherapeutic dosage, and reducing off-target toxicities. NQO1-mediated changes in glycolytic flux were readily detected in A549 (lung), MiaPaCa2 (pancreatic), and HCT-116 (colon) cancer cell lines by 2H-NMR after administration of [2H7]glucose. The deuterated metabolic products 2H-lactate and HDO were quantified, and linear relationships with glucose consumption for both products were observed. The higher concentration of HDO compared to 2H-lactate allows for more sensitive measurement of the glycolytic flux in cancer. Gas chromatography-mass spectrometry analysis agreed with the NMR results and confirmed downregulated energy metabolism in NQO1+ cells after β-lapachone treatment. The demonstrated method is ideal for measuring glycolytic rates, the effects of chemotherapeutics that target glycolysis, and has the potential for in vivo translation.

Utilizing feline oral squamous cell carcinoma patients to develop NQO1-targeted therapy

Developing effective therapies for the treatment of advanced head-and-neck squamous cell carcinoma (HNSCC) remains a major challenge, and there is a limited landscape of effective targeted therapies on the horizon. NAD(P)H:quinone oxidoreductase 1 (NQO1) is a 2-electron reductase that is overexpressed in HNSCC and presents as a promising target for the treatment of HNSCC. Current NQO1-targeted drugs are hindered by their poor oxidative tolerability in human patients, underscoring a need for better preclinical screening for oxidative toxicities for NQO1-bioactivated small molecules. Herein, we describe our work to include felines and feline oral squamous cell carcinoma (FOSCC) patients in the preclinical assessment process to prioritize lead compounds with increased tolerability and efficacy prior to full human translation. Specifically, our data demonstrate that IB-DNQ, an NQO1-targeted small molecule, is well-tolerated in FOSCC patients and shows promising initial efficacy against FOSCC tumors in proof-of-concept single agent and radiotherapy combination cohorts. Furthermore, FOSCC tumors are amenable to evaluating a variety of target-inducible couplet hypotheses, evidenced herein with modulation of NQO1 levels with palliative radiotherapy. The use of felines and their naturally-occurring tumors provide an intriguing, often underutilized tool for preclinical drug development for NQO1-targeted approaches and has broader applications for the evaluation of other anticancer strategies.

STAT1 potentiates oxidative stress revealing a targetable vulnerability that increases phenformin efficacy in breast cancer

Bioenergetic perturbations driving neoplastic growth increase the production of reactive oxygen species (ROS), requiring a compensatory increase in ROS scavengers to limit oxidative stress. Intervention strategies that simultaneously induce energetic and oxidative stress therefore have therapeutic potential. Phenformin is a mitochondrial complex I inhibitor that induces bioenergetic stress. We now demonstrate that inflammatory mediators, including IFNγ and polyIC, potentiate the cytotoxicity of phenformin by inducing a parallel increase in oxidative stress through STAT1-dependent mechanisms. Indeed, STAT1 signaling downregulates NQO1, a key ROS scavenger, in many breast cancer models. Moreover, genetic ablation or pharmacological inhibition of NQO1 using β-lapachone (an NQO1 bioactivatable drug) increases oxidative stress to selectively sensitize breast cancer models, including patient derived xenografts of HER2+ and triple negative disease, to the tumoricidal effects of phenformin. We provide evidence that therapies targeting ROS scavengers increase the anti-neoplastic efficacy of mitochondrial complex I inhibitors in breast cancer.

Complex I inhibition induces oxidative stress leading to cancer cell cytotoxicity. Here, the authors show, in breast cancer models, that inflammatory mediators can potentiate complex I inhibitor phenformin cytotoxicity through STAT1-mediated downregulation of the reactive oxygen species scavenger NQO1.

Beta-lapachone: Natural occurrence, physicochemical properties, biological activities, toxicity and synthesis

β-Lapachone is an ortho-naphthoquinone originally isolated from the heartwood of Handroanthus impetiginosus and can be obtained through synthesis from lapachol, naphthoquinones, and other aromatic compounds. β-Lapachone is well known to inhibit topoisomerase I and to induce NAD(P)H: quinone oxidoreductase 1. Currently, phase II clinical trials are being conducted for the treatment of pancreatic cancer. In view of ever-increasing scientific interest in this naphthoquinone, herein, the authors present a review of the synthesis, physicochemical properties, biological activities, and toxicity of β-lapachone. This natural compound has shown activity against several types of malignant tumors, such as lung and pancreatic cancers and melanoma. Furthermore, this ortho-naphthoquinone has antifungal and antibacterial activities, underscoring its action against resistant microorganisms and providing anti-inflammatory, antiobesity, antioxidant, neuroprotective, nephroprotective, and wound-healing properties. β-Lapachone presents low toxicity, with no signs of toxicity against alveolar macrophages, dermal fibroblast cells, hepatocytes, or kidney cells.

Tumor Microenvironment Triggered Cascade-Activation Nanoplatform for Synergistic and Precise Treatment of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common and deadliest malignancy cancers, which remains a major global health problem. At present, over 50% of patients with HCC have implemented systemic therapies, such as interventional therapy or local chemotherapy that are scarcely effective and induce serious side effects to the remaining normal liver, further limiting their clinical outcomes. Herein, a tumor microenvironment triggered cascade-activation nanoplatform (A-NP_Lap/TPZ ) is prepared based on β-lapachone (β-Lap) and tirapazamine (TPZ) for the synergistic therapy of HCC. The A-NP_Lap/TPZ exerts its targeting effect by binding to the receptor of tumor cells with an external aptamer. In the tumor microenvironment, the nanoplatform can realize H₂ O₂ -triggered disassembly to release β-Lap and TPZ. The released β-Lap generates ROS to induce tumor cell apoptosis under the catalysis of the tumor cell over-expressed NAD(P)H-quinone oxidoreductase-1 (NQO1) enzyme. In this process, oxygen is consumed to intensify tumor hypoxia, and eventually cascade activates TPZ to exert the anti-tumor effect. The studies in vitro and in vivo consistently demonstrate that the as-prepared A-NP_Lap/TPZ nanoplatform possesses an excellent synergistic anti-tumor effect. This design of nanoplatform with cascade activation effect provides a promising strategy for HCC treatment.

A novel strategy for glioblastoma treatment by induction of noptosis, an NQO1-dependent necrosis

Glioblastoma (GBM) is one of the most prevalent malignant primary tumors in the human brain. Temozolomide (TMZ), the chemotherapeutic drug for GBM treatment, induces apoptosis. Unfortunately, apoptosis-resistance to TMZ results in treatment failure. GBM shows enhanced expression of NAD(P)H: quinone oxidoreductase 1 (NQO1). Recently, noptosis, a type of NQO1-dependent necrosis, was proposed. Here, we identified that tanshindiol B (TSB) inhibits GBM growth by induction of noptosis. TSB triggered significant cell death, which did not fit the criteria of apoptosis but oxidative stress-induced necrosis. Molecular docking, cellular thermal shift assay, and NQO1 activity assay revealed that TSB bind to and promptly activated NQO1 enzyme activity. As the substrate of NQO1, TSB induced oxidative stress, which resulted in dramatic DNA damage, poly (ADP-ribose) polymerase 1 (PARP1) hyperactivation, and NAD⁺ depletion, leading to necrotic cell death. These effects of TSB were completely abolished by specific NQO1 inhibitor dicoumarol (DIC). Furthermore, the c-Jun N-terminal kinase 1/2 (JNK1/2) plays an essential role in mediating TSB-induced cell death. Besides, TSB significantly suppressed tumor growth in a zebrafish xenograft model mediated by NQO1. In conclusion, these results showed that TSB was an NQO1 substrate and triggered noptosis of GBM. TSB exhibited anti-tumor potentials in GBM both in vitro and in vivo. This study provides a novel strategy for fighting GBM through the induction of noptosis.

SIRT1 and SIRT2 Activity Control in Neurodegenerative Diseases

Sirtuins are NAD+ dependent histone deacetylases (HDAC) that play a pivotal role in neuroprotection and cellular senescence. SIRT1-7 are different homologs from sirtuins. They play a prominent role in many aspects of physiology and regulate crucial proteins. Modulation of sirtuins can thus be utilized as a therapeutic target for metabolic disorders. Neurological diseases have distinct clinical manifestations but are mainly age-associated and due to loss of protein homeostasis. Sirtuins mediate several life extension pathways and brain functions that may allow therapeutic intervention for age-related diseases. There is compelling evidence to support the fact that SIRT1 and SIRT2 are shuttled between the nucleus and cytoplasm and perform context-dependent functions in neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD). In this review, we highlight the regulation of SIRT1 and SIRT2 in various neurological diseases. This study explores the various modulators that regulate the activity of SIRT1 and SIRT2, which may further assist in the treatment of neurodegenerative disease. Moreover, we analyze the structure and function of various small molecules that have potential significance in modulating sirtuins, as well as the technologies that advance the targeted therapy of neurodegenerative disease.

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

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.

MTHFD2 Blockade Enhances the Efficacy of β-Lapachone Chemotherapy With Ionizing Radiation in Head and Neck Squamous Cell Cancer

Head and Neck Squamous Cell Cancer (HNSCC) presents with multiple treatment challenges limiting overall survival rates and affecting patients' quality of life. Amongst these, resistance to radiation therapy constitutes a major clinical problem in HNSCC patients compounded by origin, location, and tumor grade that limit tumor control. While cisplatin is considered the standard radiosensitizing agent for definitive or adjuvant radiotherapy, in recurrent tumors or for palliative care other chemotherapeutics such as the antifolates methotrexate or pemetrexed are also being utilized as radiosensitizers. These drugs inhibit the enzyme dihydrofolate reductase, which is essential for DNA synthesis and connects the 1-C/folate metabolism to NAD(P)H and NAD(P)⁺ balance in cells. In previous studies, we identified MTHFD2, a mitochondrial enzyme involved in folate metabolism, as a key contributor to NAD(P)H levels in the radiation-resistant cells and HNSCC tumors. In the study presented here, we investigated the role of MTHFD2 in the response to radiation alone and in combination with β-lapachone, a NQO1 bioactivatable drug, which generates reactive oxygen species concomitant with NAD(P)H oxidation to NAD(P)⁺. These studies are performed in a matched HNSCC cell model of response to radiation: the radiation resistant rSCC-61 and radiation sensitive SCC-61 cells reported earlier by our group. Radiation resistant rSCC-61 cells had increased sensitivity to β-lapachone compared to SCC-61 and knockdown of MTHFD2 in rSCC-61 cells further potentiated the cytotoxicity of β-lapachone with radiation in a dose and time-dependent manner. rSCC-61 MTHFD2 knockdown cells irradiated and treated with β-lapachone showed increased PARP1 activation, inhibition of mitochondrial respiration, decreased respiration-linked ATP production, and increased mitochondrial superoxide and protein oxidation as compared to control rSCC-61 scrambled shRNA. Thus, these studies point to MTHFD2 as a potential target for development of radiosensitizing chemotherapeutics and potentiator of β-lapachone cytotoxicity.

A comprehensive review on β-lapachone: Mechanisms, structural modifications, and therapeutic potentials

β-Lapachone (β-lap, 1), an ortho-naphthoquinone natural product isolated from the lapacho tree (Tabebuia avellanedae) in many regions of South America, has received extensive attention due to various pharmacological activities, such as antitumor, anti-Trypanosoma cruzi, anti-Mycobacterium tuberculosis, antibacterial, and antimalarial activities. Related mechanisms of β-lap have been widely investigated for a full understanding of its therapeutic potentials. Numerous derivatives of β-lap have been reported with aims to generate new chemical entities, improve the corresponding biological potency, and overcome disadvantages of its physical and chemical properties and safety profiles. This review will give insight into the pharmacological mechanisms of β-lap and provide a comprehensive understanding of its structural modifications with regard to different therapeutic potentials. The available clinical trials related to β-lap and its derivatives are also summarized.

Strategies to reduce the risk of platinum containing antineoplastic drug-induced ototoxicity

INTRODUCTION

Cisplatin is a highly effective chemotherapeutic agent against a variety of solid tumors in adults and in children. Unfortunately, a large percentage of patients suffer permanent sensorineural hearing loss. Up to 60% of children and at least 50% of adults suffer this complication that seriously compromises their quality of life. Hearing loss is due to damage to the sensory cells in the inner ear. The mechanisms of cochlear damage are still being investigated. However, it appears that inner ear damage is triggered by reactive oxygen species (ROS) formation and inflammation 34.

AREAS COVERED

We discuss a number of potential therapeutic targets that can be addressed to provide hearing protection. These strategies include enhancing the endogenous antioxidant pathways, heat shock proteins, G protein coupled receptors and counteracting ROS and reactive nitrogen species, and blocking pathways that produce inflammation, including TRPV1 and STAT1 36.

EXPERT OPINION

Numerous potential protective agents show promise in animal models by systemic or local administration. However, clinical trials have not shown much efficacy to date with the exception of sodium thiosulfate. There is an urgent need to discover safe and effective protective agents that do not interfere with the efficacy of cisplatin against tumors yet preserve hearing 151.

A Novel Redox Modulator Induces a GPX4-Mediated Cell Death That Is Dependent on Iron and Reactive Oxygen Species

Redox modulators have been developed as an attractive approach to treat cancer. Herein, we report the synthesis, identification, and biological evaluation of a quinazolinedione reactive oxygen species (ROS) inducer, QD394, with significant cytotoxicity in pancreatic cancer cells. QD394 shows a transcriptomic profile remarkably similar to napabucasin, a cancer stemness inhibitor. Both small molecules inhibit STAT3 phosphorylation, increase cellular ROS, and decrease the GSH/GSSG ratio. Moreover, QD394 causes an iron- and ROS-dependent, GPX4 mediated cell death, suggesting ferroptosis as a major mechanism. Importantly, QD394 decreases the expression of LRPPRC and PNPT1, two proteins involved in mitochondrial RNA catabolic processes and both negatively correlated with the overall survival of pancreatic cancer patients. Pharmacokinetics-guided lead optimization resulted in the derivative QD394-Me, which showed improved plasma stability and reduced toxicity in mice compared to QD394. Overall, QD394 and QD394-Me represent novel ROS-inducing drug-like compounds warranting further development for the treatment of pancreatic cancer.

ROS-Mediated Therapeutic Strategy in Chemo-/Radiotherapy of Head and Neck Cancer

Head and neck cancer is a highly genetic and metabolic heterogeneous collection of malignancies of the lip, oral cavity, salivary glands, pharynx, esophagus, paranasal sinuses, and larynx with five-year survival rates ranging from 12% to 93%. Patients with head and neck cancer typically present with advanced stage III, IVa, or IVb disease and are treated with comprehensive modality including chemotherapy, radiotherapy, and surgery. Despite advancements in treatment modality and technique, noisome recurrence, invasiveness, and resistance as well as posttreatment complications severely influence survival rate and quality of life. Thus, new therapeutic strategies are urgently needed that offer enhanced efficacy with less toxicity. ROS in cancer cells plays a vital role in regulating cell death, DNA repair, stemness maintenance, metabolic reprogramming, and tumor microenvironment, all of which have been implicated in resistance to chemo-/radiotherapy of head and neck cancer. Adjusting ROS generation and elimination to reverse the resistance of cancer cells without impairing normal cells show great hope in improving the therapeutic efficacy of chemo-/radiotherapy of head and neck cancer. In the current review, we discuss the pivotal and targetable redox-regulating system including superoxide dismutases (SODs), tripeptide glutathione (GSH), thioredoxin (Trxs), peroxiredoxins (PRXs), nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/keap1), and mitochondria electron transporter chain (ETC) complexes and their roles in regulating ROS levels and their clinical significance implicated in chemo-/radiotherapy of head and neck cancer. We also summarize several old drugs (referred to as the non-anti-cancer drugs used in other diseases for a long time) and small molecular compounds as well as natural herbs which effectively modulate cellular ROS of head and neck cancer to synergize the efficacy of conventional chemo-/radiotherapy. Emerging interdisciplinary techniques including photodynamic, nanoparticle system, and Bio-Electro-Magnetic-Energy-Regulation (BEMER) therapy are promising measures to broaden the potency of ROS modulation for the benefit of chemo-/radiotherapy in head and neck cancer.

Bioanalytical method development and validation of a liquid chromatography-tandem mass spectrometry method for determination of β-lapachone in human plasma

The purpose of this work was to develop and validate a rapid, sensitive and robust liquid chromatography tandem mass spectrometric method for the quantification of β-lapachone in human plasma and to use that method to analyze human clinical samples. Sample preparation for the developed method involved liquid-liquid extraction using ethyl acetate for extraction of β-lapachone and cryptotanshinone (internal standard) from human plasma. Chromatographic resolution was achieved on a Kinetex C18 column using a gradient elution and a chromatographic flow rate of 0.5 mL/min. The retention times of β-lapachone and cryptotanshinone were 1.98 and 2.28 min, respectively, and the method had a total run time of 4 min. Bioanalytical method validation was conducted in accordance with the United States Food and Drug Administration regulatory guidelines. The method was validated over 2 calibration ranges in order to support high- and low-dose clinical studies. Calibration curve-1 covered the range of 0.25-50 ng/mL and calibration curve-2 covered the range of 50-2000 ng/mL. The method was determined to be accurate (percent relative errors between -1.07 to 5.36 %), precise (percent relative standard deviations less than 7.4), and sensitive (LLOQ 0.25 ng/mL). β-lapachone was determined to be stable (% change from time = 0 between -11.6 and 12.6 %) across the autosampler, benchtop, freeze/thaw and long-term (63 days) stability studies. The validated bioanalytical method was employed to determine β-lapachone concentrations in human plasma samples from a clinical study.

Induction of programmed necrosis: A novel anti-cancer strategy for natural compounds

Cell death plays a critical role in organism development and the pathogenesis of diseases. Necrosis is considered a non-programmed cell death in an extreme environment. Recent advances have provided solid evidence that necrosis could be programmed and quite a few types of programmed necrosis, such as necroptosis, ferroptosis, pyroptosis, paraptosis, mitochondrial permeability transition-driven necrosis, and oncosis, have been identified. The specific biomarkers, detailed signaling, and precise pathophysiological importance of programmed necrosis are yet to be clarified, but these forms of necrosis provide novel strategies for the treatment of various diseases, including cancer. Natural compounds are a unique source of lead compounds for the discovery of anti-cancer drugs. Natural compounds can induce both apoptosis and programmed necrosis. In this review, we summarized the recent progress of programmed necrosis and introduced their natural inducers. Noptosis, which is a novel type of programmed necrosis that is strictly dependent on NAD(P)H: quinone oxidoreductase 1-derived oxidative stress was proposed. Furthermore, the anti-cancer strategies that take advantage of programmed necrosis and the main concerns from the scientific community in this regard were discussed.

In silico, in vitro and in vivo evaluation of natural Bignoniaceous naphthoquinones in comparison with atovaquone targeting the selection of potential antimalarial candidates

The natural naphthoquinones lapachol, α- and β-lapachone are found in Bignoniaceous Brazilian plant species of the Tabebuia genus (synonym Handroanthus) and are recognized for diverse bioactivities, including as antimalarial. The aim of the present work was to perform in silico, in vitro and in vivo studies to evaluating the antimalarial potential of these three naphthoquinones in comparison with atovaquone, a synthetic antimalarial. The ADMET properties of these compounds were predicted in silico by the preADMET program. The in vitro toxicity assays were experimentally determined in immortalized and tumoral cells from different organs. In vivo acute oral toxicity was also evaluated for lapachol. Several favorable pharmacokinetics data were predicted although, as expected, high cytotoxicity was experimentally determined for β-lapachone. Lapachol was not cytotoxic or showed low cytotoxicity to all of the cells assayed (HepG2, A549, Neuro 2A, LLC-PK1, MRC-5), it was nontoxic in the acute oral test and disclosed the best parasite selectivity index in the in vitro assays against chloroquine resistant Plasmodium falciparum W2 strain. On the other hand, α- and β-lapachone were more potent than lapachol in the antiplasmodial assays but with low parasite selectivity due to their cytotoxicity. The diversity of data here reported disclosed lapachol as a promising candidate to antimalarial drug development.

2-Methoxy-6-acetyl-7-methyljuglone (MAM) induced programmed necrosis in glioblastoma by targeting NAD(P)H: Quinone oxidoreductase 1 (NQO1)

Glioblastoma (GBM) are the most malignant brain tumors in humans and have a very poor prognosis. Temozolomide (TMZ), the only chemotherapeutic drug for GBM treatment, induced apoptosis but frequently developed resistance. Non-apoptotic cell death offers an alternative strategy to fight cancers. Our previous studies showed that 2-methoxy-6-acetyl-7-methyljuglone (MAM), a natural product, induced necroptosis in lung and colon cancer cells. The current study is designed to investigate its therapeutic potentials for GBM with in vitro and in vivo models. The protein expression of NAD(P)H: quinone oxidoreductase 1 (NQO1) in human GBM specimens were detected by immunohistochemistry. Effect of MAM on NQO1 was measured by recombinant protein and cellular thermal shift assay. The roles of NQO1 activation, superoxide (O_2^-) generation, calcium (Ca²⁺) accumulation, and c-Jun N-terminal kinase (JNK1/2) activation in MAM-induced cell death in U87 and U251 glioma cells were investigated. The effect of MAM on tumor growth was tested with a U251 tumor xenograft zebrafish model. Results showed that the NQO1 expression is positively correlated with the degree of malignancy in GBM tissues. MAM could directly bind and activate NQO1. Furthermore, MAM treatment induced rapid O_2^- generation, cytosolic Ca²⁺ accumulation, and sustained JNK1/2 activation. In addition, MAM significantly suppressed tumor growth in the zebrafish model. In conclusion, MAM induced GBM cell death by triggering an O_2^-/Ca²⁺/JNK1/2 dependent programmed necrosis. NQO1 might be the potential target for MAM and mediated its anticancer effect. This non-apoptotic necrosis might have therapeutic potentials for GBM treatment.