Browsing by Author "Carta, Fabrizio"

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    Pharmacological inhibition of Carbonic Anhydrase IX and XII to enhance targeting of acute myeloid leukaemia cells under hypoxic conditions
    (Wiley, 2021-12) Chen, Fangli; Licarete, Emilia; Wu, Xue; Petrusca, Daniela; Maguire, Callista; Jacobsen, Max; Colter, Austyn; Sandusky, George E.; Czader, Magdalena; Capitano, Maegan L.; Ropa, James P.; Boswell, H. Scott; Carta, Fabrizio; Supuran, Claudiu T.; Parkin, Brian; Fishel, Melissa L.; Konig, Heiko; Pathology and Laboratory Medicine, School of Medicine
    Acute myeloid leukaemia (AML) is an aggressive form of blood cancer that carries a dismal prognosis. Several studies suggest that the poor outcome is due to a small fraction of leukaemic cells that elude treatment and survive in specialised, oxygen (O2 )-deprived niches of the bone marrow. Although several AML drug targets such as FLT3, IDH1/2 and CD33 have been established in recent years, survival rates remain unsatisfactory, which indicates that other, yet unrecognized, mechanisms influence the ability of AML cells to escape cell death and to proliferate in hypoxic environments. Our data illustrates that Carbonic Anhydrases IX and XII (CA IX/XII) are critical for leukaemic cell survival in the O2 -deprived milieu. CA IX and XII function as transmembrane proteins that mediate intracellular pH under low O2 conditions. Because maintaining a neutral pH represents a key survival mechanism for tumour cells in O2 -deprived settings, we sought to elucidate the role of dual CA IX/XII inhibition as a novel strategy to eliminate AML cells under hypoxic conditions. Our findings demonstrate that the dual CA IX/XII inhibitor FC531 may prove to be of value as an adjunct to chemotherapy for the treatment of AML.
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    Regulation of HIF1 under Hypoxia by APE1/Ref-1 Impacts CA9 Expression: Dual-Targeting in Patient-Derived 3D Pancreatic Cancer Models
    (Office of the Vice Chancellor for Research, 2016-04-08) Logsdon, Derek P.; Grimard, Michelle; Shahda, Safi; Zyromski, Nicholas; Schipani, Ernestina; Carta, Fabrizio; Supuran, Claudiu T.; Korc, Murray; Ivan, Mircea; Kelley, Mark R.; Fishel, Melissa L.
    Abstract Half of all patients diagnosed with pancreatic ductal adenocarcinoma (PDAC) die within a year despite extensive surgery and/or a highly aggressive chemotherapy regimen. Several mechanisms are proposed to play a role in PDAC therapeutic resistance, including reactive stroma and hypoxia. Hypoxia signaling creates a more aggressive phenotype with increased metastatic potential and impaired therapeutic efficacy. Carbonic anhydrase IX (CA9) functions as part of the cellular hypoxia response to regulate intracellular pH, promoting cell survival. Apurinic/Apyrimidinic Endonuclease-1-Reduction/oxidation Effector Factor 1 (APE1/Ref-1) is a multi-functional protein with two major activities: an endonuclease function in DNA base excision repair and a redox signaling function that reduces oxidized transcription factors, enabling them to bind to their DNA target sequences. APE1/Ref-1 regulates several transcription factors involved in survival mechanisms, tumor growth, and hypoxia signaling. We explored the mechanisms underlying PDAC cell responses to hypoxia and modulation of APE1/Ref-1 redox signaling control of hypoxia inducible factor 1 alpha (HIF1), a critical factor in hypoxiainduced CA9 transcription. We hypothesized that obstructing the HIF-CA9 axis at two points via APE1/Ref-1 inhibition and CA9 inhibition will result in enhanced PDAC cell killing under hypoxic conditions. Methods: We performed qRT-PCR and Western Blots to confirm changes in CA9 expression in PDAC cells following APE1/Ref-1 inhibition and hypoxia exposure. Proliferation assays were used to assess cell killing following inhibition of APE1/Ref-1 and CA9 under hypoxia. Ex vivo 3-Dimensional co-culture models including both tumor and CAFs were used to examine whether we could enhance the efficacy of APE1/Ref-1 and/or CA9 inhibition with a dual-targeting approach to kill tumor spheroids. Results: HIF1-mediated induction of CA9 is significantly diminished in PDAC cells following APE1/Ref-1 redox inhibition. Additionally, dual-targeting of APE1/Ref-1 and CA9 reduces PDAC tumor cell growth under hypoxic conditions and in 3D tumor co-cultures.
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    Regulation of HIF1α under Hypoxia by APE1/Ref-1 Impacts CA9 Expression: Dual Targeting in Patient-Derived 3D Pancreatic Cancer Models
    (AACR, 2016-11-01) Logsdon, Derek P.; Grimard, Michelle; Luo, Meihua; Shahda, Safi; Jiang, Yanlin; Tong, Yan; Yu, Zhangsheng; Zyromski, Nicholas; Schipani, Ernestina; Carta, Fabrizio; Supuran, Claudiu T.; Korc, Murray; Ivan, Mircea; Kelley, Mark R.; Fishel, Melissa L.; Department of Pediatrics, School of Medicine
    Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related mortality in the United States. Aggressive treatment regimens have not changed the disease course, and the median survival has just recently reached a year. Several mechanisms are proposed to play a role in PDAC therapeutic resistance, including hypoxia, which creates a more aggressive phenotype with increased metastatic potential and impaired therapeutic efficacy. AP Endonuclease-1/Redox Effector Factor 1 (APE1/Ref-1) is a multifunctional protein possessing a DNA repair function in base excision repair and the ability to reduce oxidized transcription factors, enabling them to bind to their DNA target sequences. APE1/Ref-1 regulates several transcription factors involved in survival mechanisms, tumor growth, and hypoxia signaling. Here, we explore the mechanisms underlying PDAC cell responses to hypoxia and modulation of APE1/Ref-1 redox signaling activity, which regulates the transcriptional activation of hypoxia-inducible factor 1 alpha (HIF1α). Carbonic anhydrase IX (CA9) is regulated by HIF1α and functions as a part of the cellular response to hypoxia to regulate intracellular pH, thereby promoting cell survival. We hypothesized that modulating APE1/Ref-1 function will block activation of downstream transcription factors, STAT3 and HIF1α, interfering with the hypoxia-induced gene expression. We demonstrate APE1/Ref-1 inhibition in patient-derived and established PDAC cells results in decreased HIF1α–mediated induction of CA9. Furthermore, an ex vivo three-dimensional tumor coculture model demonstrates dramatic enhancement of APE1/Ref-1–induced cell killing upon dual targeting of APE1/Ref-1 and CA9. Both APE1/Ref-1 and CA9 are under clinical development; therefore, these studies have the potential to direct novel PDAC therapeutic treatment.