Browsing by Author "Singh, Naveen"
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Item Detecting Attomolar DNA-Damaging Anticancer Drug Activity in Cell Lysates with Electrochemical DNA Devices(American Chemical Society, 2021-07-23) Wettasinghe, Ashan P.; Singh, Naveen; Starcher, Colton L.; DiTusa, Chloe C.; Ishak-Boushaki, Zakari; Kahanda, Dimithree; McMullen, Reema; Motea, Edward A.; Slinker, Jason D.; Biochemistry and Molecular Biology, School of MedicineHere, we utilize electrochemical DNA devices to quantify and understand the cancer-specific DNA-damaging activity of an emerging drug in cellular lysates at femtomolar and attomolar concentrations. Isobutyl-deoxynyboquinone (IB-DNQ), a potent and tumor-selective NAD(P)H quinone oxidoreductase 1 (NQO1) bioactivatable drug, was prepared and biochemically verified in cancer cells highly expressing NQO1 (NQO1+) and knockdowns with low NQO1 expression (NQO1−) by Western blot, NQO1 activity analysis, survival assays, oxygen consumption rate, extracellular acidification rate, and peroxide production. Lysates from these cells and the IB-DNQ drug were then introduced to a chip system bearing an array of DNA-modified electrodes, and their DNA-damaging activity was quantified by changes in DNA-mediated electrochemistry arising from base-excision repair. Device-level controls of NQO1 activity and kinetic analysis were used to verify and further understand the IB-DNQ activity. A 380 aM IB-DNQ limit of detection and a 1.3 fM midpoint of damage were observed in NQO1+ lysates, both metrics 2 orders of magnitude lower than NQO1− lysates, indicating the high IB-DNQ potency and selectivity for NQO1+ cancers. The device-level damage midpoint concentration in NQO1+ lysates was over 8 orders of magnitude lower than cell survival benchmarks, likely due to poor IB-DNQ cellular uptake, demonstrating that these devices can identify promising drugs requiring improved cell permeability. Ultimately, these results indicate the noteworthy potency and selectivity of IB-DNQ and the high sensitivity and precision of electrochemical DNA devices to analyze agents/drugs involved in DNA-damaging chemotherapies.Item Following Anticancer Drug Activity in Cell Lysates with DNA Devices(Elsevier, 2018-11) Kahanda, Dimithree; Singh, Naveen; Boothman, David A.; Slinker, Jason D.; Biochemistry and Molecular Biology, School of MedicineThere is a great need to track the selectivity of anticancer drug activity and to understand the mechanisms of associated biological activity. Here we focus our studies on the specific NQO1 bioactivatable drug, ß-lapachone, which is in several Phase I clinical trials to treat human non-small cell lung, pancreatic and breast cancers. Multi-electrode chips with electrochemically-active DNA monolayers are used to track anticancer drug activity in cellular lysates and correlate cell death activity with DNA damage. Cells were prepared from the triple-negative breast cancer (TNBC) cell line, MDA-MB-231 (231) to be proficient or deficient in expression of the NAD(P)H:quinone oxidoreductase 1 (NQO1) enzyme, which is overexpressed in most solid cancers and lacking in control healthy cells. Cells were lysed and added to chips, and the impact of β-lapachone (β-lap), an NQO1-dependent DNA-damaging drug, was tracked with DNA electrochemical signal changes arising from drug-induced DNA damage. Electrochemical DNA devices showed a 3.7-fold difference in the electrochemical responses in NQO1+ over NQO1− cell lysates, as well as 10–20-fold selectivity to catalase and dicoumarol controls that deactivate DNA damaging pathways. Concentration-dependence studies revealed that 1.4 µM β-lap correlated with the onset of cell death from viability assays and the midpoint of DNA damage on the chip, and 2.5 µM β-lap correlated with the midpoint of cell death and the saturation of DNA damage on the chip. Results indicate that these devices could inform therapeutic decisions for cancer treatment.Item IB-DNQ and Rucaparib dual treatment alters cell cycle regulation and DNA repair in triple negative breast cancer cells(bioRxiv, 2024-05-18) Runnebohm, Avery M.; Wijeratne, H. R. Sagara; Peck Justice, Sarah A.; Wijeratne, Aruna B.; Roy, Gitanjali; Singh, Naveen; Hergenrother, Paul; Boothman, David A.; Motea, Edward A.; Mosley, Amber L.; Biochemistry and Molecular Biology, School of MedicineBackground: 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.Item MTHFD2 Blockade Enhances the Efficacy of β-Lapachone Chemotherapy With Ionizing Radiation in Head and Neck Squamous Cell Cancer(Frontiers, 2020-11-11) Shukla, Kirtikar; Singh, Naveen; Lewis, Joshua E.; Tsang, Allen W.; Boothman, David A.; Kemp, Melissa L.; Biochemistry and Molecular Biology, School of MedicineHead 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.Item NQO1-Bioactivatable Therapeutics as Radiosensitizers for Cancer Treatment(InTechOpen, 2020-02-13) Singh, Naveen; Motea, Edward A.; Huang, Xiumei; Starcher, Colton L.; Silver, Jayne; Yeh, I.-Ju; Pay, S. Louise; Su, Xiaolin; Russ, Kristen A.; Boothman, David A.; Bey, Erik A.; Biochemistry and Molecular Biology, School of MedicineDeveloping cancer therapeutics that radiosensitize in a tumor-selective manner remains an ideal. We developed a novel means of radiosensitization, exploiting NAD(P)H:Quinone Oxidoreductase 1 (NQO1) overexpression, and lowered catalase expression in solid human tumors using NQO1-bioactivatable drugs. Non-small cell lung (NSCLC), pancreatic (PDAC), prostate, and breast cancers overexpress NQO1. Ionizing radiation (IR) creates a spectrum of DNA lesions, including lethal DNA double-strand breaks (DSBs), and mutagenic but rarely lethal altered DNA bases and DNA single-strand breaks (SSBs). NQO1-bioactivatable drugs (e.g., β-lapachone and deoxynyboquiones) also promote abasic DNA lesions and SSBs. These hyperactivate poly (ADP-ribose) polymerase 1 (PARP1) and dramatically increase calcium release from the endoplasm reticulum (ER). Exposure of human cancer cells overexpressing NQO1 to NQO1-bioactivatable drugs immediately following IR, therefore, hyperactivates PARP1 synergistically, which in turn depletes NAD+ and ATP, inhibiting DSB repair. Ultimately, this leads to cell death. Combining IR with NQO1-bioactivatable drugs allows for a reduction in drug dose. Similarly, a lower IR dose can be used in combination with the drug, reducing the effects of IR on normal tissue. The combination treatment is effective in preclinical animal models with NSCLC, prostate, and head and neck xenografts, indicating that clinical trials are warranted.Item NQO1-Bioactivatable Therapeutics as Radiosensitizers for Cancer Treatment(IntechOpen, 2020) Singh, Naveen; Motea, Edward A.; Huang, Xiumei; Starcher, Colton L.; Silver, Jayne; Yeh, I-Ju; Pay, S. Louise; Su, Xiaolin; Russ, Kristen A.; Boothman, David A.; Bey, Erik A.; Biochemistry and Molecular Biology, School of MedicineDeveloping cancer therapeutics that radiosensitize in a tumor-selective manner remains an ideal. We developed a novel means of radiosensitization, exploiting NAD(P)H:Quinone Oxidoreductase 1 (NQO1) overexpression, and lowered catalase expression in solid human tumors using NQO1-bioactivatable drugs. Non-small cell lung (NSCLC), pancreatic (PDAC), prostate, and breast cancers overexpress NQO1. Ionizing radiation (IR) creates a spectrum of DNA lesions, including lethal DNA double-strand breaks (DSBs), and mutagenic but rarely lethal altered DNA bases and DNA single-strand breaks (SSBs). NQO1-bioactivatable drugs (e.g., β-lapachone and deoxynyboquiones) also promote abasic DNA lesions and SSBs. These hyperactivate poly (ADP-ribose) polymerase 1 (PARP1) and dramatically increase calcium release from the endoplasm reticulum (ER). Exposure of human cancer cells overexpressing NQO1 to NQO1-bioactivatable drugs immediately following IR, therefore, hyperactivates PARP1 synergistically, which in turn depletes NAD+ and ATP, inhibiting DSB repair. Ultimately, this leads to cell death. Combining IR with NQO1-bioactivatable drugs allows for a reduction in drug dose. Similarly, a lower IR dose can be used in combination with the drug, reducing the effects of IR on normal tissue. The combination treatment is effective in preclinical animal models with NSCLC, prostate, and head and neck xenografts, indicating that clinical trials are warranted.Item NQO1-dependent, tumor-selective radiosensitization of non-small cell lung cancers(American Association for Cancer Research, 2019-04-15) Motea, Edward A.; Huang, Xiumei; Singh, Naveen; Kilgore, Jessica; Williams, Noelle; Xie, Xian-Jin; Gerber, David E.; Beg, Muhammad Shaalan; Bey, Erik A.; Boothman, David A.; Biochemistry and Molecular Biology, School of MedicinePurpose: Development of tumor-specific therapies for the treatment of recalcitrant non-small cell lung cancers (NSCLCs) are urgently needed. Here, we investigated the ability of ß-lapachone (ß-lap, ARQ761 in clinical form) to selectively potentiate the effects of ionizing radiation (IR, 1–3 Gy) in NSCLCs that over-express NAD(P)H:Quinone Oxidoreductase 1 (NQO1). Experimental Design: The mechanism of lethality of low dose IR in combination with sublethal doses of ß-lap were evaluated in NSCLC lines in vitro and validated in subcutaneous and orthotopic xenograph models in vivo. Pharmacokinetics and pharmacodynamics (PK/PD) studies comparing single versus co-treatments were performed to validate therapeutic efficacy and mechanism of action. Results: ß-Lap administration after IR treatment hyperactivated PARP, greatly lowered NAD+/ATP levels, and increased DSB lesions over time in vitro. Radiosensitization of orthotopic, as well as subcutaneous, NSCLCs occurred with high apparent cures (>70%), even though 1/8 ß-lap doses reach subcutaneous versus orthotopic tumors. No methemoglobinemia or long-term toxicities were noted in any normal tissues, including mouse liver that expresses the highest level of NQO1 (~12 Units) of any normal tissue. PK/PD responses confirm that IR + ß-lap treatments hyperactivate PARP activity, greatly lower NAD+/ATP levels and dramatically inhibit DSB repair in exposed NQO1+ cancer tissue, while low NQO1 levels and high levels of Catalase in associated normal tissue were protective. Conclusion: Our data suggest that combination of sublethal doses of ß-lap and IR is a viable approach to selectively treat NQO1-overexpressing NSCLC and warrant a clinical trial using low-dose IR + ß-lapachone against patients with NQO1+ NSCLCs.Item Targeting Base Excision Repair in Cancer: NQO1-Bioactivatable Drugs Improve Tumor Selectivity and Reduce Treatment Toxicity Through Radiosensitization of Human Cancer(Frontiers, 2020-08-19) Starcher, Colton L.; Pay, S. Louise; Singh, Naveen; Yeh, I.-Ju; Bhandare, Snehal B.; Su, Xiaolin; Huang, Xiumei; Bey, Erik A.; Motea, Edward A.; Boothman, David A.; Biochemistry and Molecular Biology, School of MedicineIonizing radiation (IR) creates lethal DNA damage that can effectively kill tumor cells. However, the high dose required for a therapeutic outcome also damages healthy tissue. Thus, a therapeutic strategy with predictive biomarkers to enhance the beneficial effects of IR allowing a dose reduction without losing efficacy is highly desirable. NAD(P)H:quinone oxidoreductase 1 (NQO1) is overexpressed in the majority of recalcitrant solid tumors in comparison with normal tissue. Studies have shown that NQO1 can bioactivate certain quinone molecules (e.g., ortho-naphthoquinone and β-lapachone) to induce a futile redox cycle leading to the formation of oxidative DNA damage, hyperactivation of poly(ADP-ribose) polymerase 1 (PARP1), and catastrophic depletion of NAD+ and ATP, which culminates in cellular lethality via NAD+-Keresis. However, NQO1-bioactivatable drugs induce methemoglobinemia and hemolytic anemia at high doses. To circumvent this, NQO1-bioactivatable agents have been shown to synergize with PARP1 inhibitors, pyrimidine radiosensitizers, and IR. This therapeutic strategy allows for a reduction in the dose of the combined agents to decrease unwanted side effects by increasing tumor selectivity. In this review, we discuss the mechanisms of radiosensitization between NQO1-bioactivatable drugs and IR with a focus on the involvement of base excision repair (BER). This combination therapeutic strategy presents a unique tumor-selective and minimally toxic approach for targeting solid tumors that overexpress NQO1.Item Targeting NAD+ Metabolism to Enhance Radiation Therapy Responses(Elsevier, 2019-01) Lewis, Joshua E.; Singh, Naveen; Holmila, Reetta J.; Sumer, Baran D.; Williams, Noelle S.; Furdui, Cristina M.; Kemp, Melissa L.; Boothman, David A.; Biochemistry and Molecular Biology, School of MedicineNicotinamide adenine dinucleotide (NAD+) metabolism is integrally connected with the mechanisms of action of radiation therapy and is altered in many radiation-resistant tumors. This makes NAD+ metabolism an ideal target for therapies that increase radiation sensitivity and improve patient outcomes. This review provides an overview of NAD+ metabolism in the context of the cellular response to ionizing radiation, as well as current therapies that target NAD+ metabolism to enhance radiation therapy responses. Additionally, we summarize state-of-the-art methods for measuring, modeling, and manipulating NAD+ metabolism, which are being used to identify novel targets in the NAD+ metabolic network for therapeutic interventions in combination with radiation therapy.Item Therapeutic Strategies and Biomarkers to Modulate PARP Activity for Targeted Cancer Therapy(MDPI, 2020-04-14) Singh, Naveen; Pay, S. Louise; Bhandare, Snehal B.; Arimpur, Udhaya; Motea, Edward A.; Biochemistry and Molecular Biology, School of MedicinePoly-(ADP-ribose) polymerase 1 (PARP1) is commonly known for its vital role in DNA damage response and repair. However, its enzymatic activity has been linked to a plethora of physiological and pathophysiological transactions ranging from cellular proliferation, survival and death. For instance, malignancies with BRCA1/2 mutations heavily rely on PARP activity for survival. Thus, the use of PARP inhibitors is a well-established intervention in these types of tumors. However, recent studies indicate that the therapeutic potential of attenuating PARP1 activity in recalcitrant tumors, especially where PARP1 is aberrantly overexpressed and hyperactivated, may extend its therapeutic utility in wider cancer types beyond BRCA-deficiency. Here, we discuss treatment strategies to expand the tumor-selective therapeutic application of PARP inhibitors and novel approaches with predictive biomarkers to perturb NAD+ levels and hyperPARylation that inactivate PARP in recalcitrant tumors. We also provide an overview of genetic alterations that transform non-BRCA mutant cancers to a state of “BRCAness” as potential biomarkers for synthetic lethality with PARP inhibitors. Finally, we discuss a paradigm shift for the use of novel PARP inhibitors outside of cancer treatment, where it has the potential to rescue normal cells from severe oxidative damage during ischemia-reperfusion injury induced by surgery and radiotherapy.