Blockers of carbonic anhydrase can cause increase of retinal capillary diameter, decrease of extracellular and increase of intracellular pH in rat retinal organ culture

Carbonic anhydrase IX (CAIX) is a hypoxia-related protein that plays a role in proliferation in solid tumours. However, how CAIX increases proliferation and metastasis in solid tumours is unclear. The objective of this study was to investigate how a synthetic CAIX inhibitor triggers apoptosis in the HeLa cell line. The intracellular effects of CAIX inhibition were determined with AO/EB, AnnexinV-PI, and γ-H2AX staining; measurements of intracellular pH (pHi), reactive oxygen species (ROS), and mitochondrial membrane potential (MMP); and analyses of cell cycle, apoptotic, and autophagic modulator gene expression (Bax, Bcl-2, caspase-3, caspase-8, caspase-9, caspase-12, Beclin, and LC3), caspase protein level (pro-caspase 3 and cleaved caspase-3, -8, -9), cleaved PARP activation, and CAIX protein level. Sulphonamide CAIX inhibitor E showed the lowest IC50 and the highest selectivity index in CAIX-positive HeLa cells. CAIX inhibition changed the morphology of HeLa cells and increased the ratio of apoptotic cells, dramatically disturbing the homeostasis of intracellular pHi, MMP and ROS levels. All these phenomena consequent to CA IX inhibition triggered apoptosis and autophagy in HeLa cells. Taken together, these results further endorse the previous findings that CAIX inhibitors represent an important therapeutic strategy, which is worth pursuing in different cancer types, considering that presently only one sulphonamide inhibitor, SLC-0111, has arrived in Phase Ib/II clinical trials as an antitumour/antimetastatic drug.

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Effect of PCMBS on CO2permeability of Xenopus oocytes expressing aquaporin 1 or its C189S mutant

AJP Cell Physiology ◽

10.1152/ajpcell.1998.275.6.c1481 ◽

1998 ◽

Vol 275 (6) ◽

pp. C1481-C1486 ◽

Cited By ~ 135

Author(s):

Gordon J. Cooper ◽

Walter F. Boron

Keyword(s):

Carbonic Anhydrase ◽

Intracellular Ph ◽

Xenopus Oocytes ◽

Membrane Lipid ◽

Wild Type ◽

Aquaporin 1 ◽

Gas Channel ◽

A Cell ◽

Pass Through ◽

Rule Out

A recent study on Xenopus oocytes [N. L. Nakhoul, M. F. Romero, B. A. Davis, and W. F. Boron. Am. J. Physiol. 274 ( Cell Physiol. 43): C543–548, 1998] injected with carbonic anhydrase showed that expressing aquaporin 1 (AQP1) increases by ∼40% the rate at which exposing the cell to CO2 causes intracellular pH to fall. This observation is consistent with several interpretations. Overexpressing AQP1 might increase apparent CO2 permeability by 1) allowing CO2 to pass through AQP1, 2) stimulating injected carbonic anhydrase, 3) enhancing the CO2 solubility of the membrane’s lipid, or 4) increasing the expression of a native “gas channel.” The purpose of the present study was to distinguish among these possibilities. We found that expressing the H2O channel AQP1 in Xenopus oocytes increases the CO2 permeability of oocytes in an expression-dependent fashion, whereas expressing the K+ channel ROMK1 has no effect. The mercury derivative p-chloromercuriphenylsulfonic acid (PCMBS), which inhibits the H2O movement through AQP1, also blocks the AQP1-dependent increase in CO2 permeability. The mercury-insensitive C189S mutant of AQP1 increases the CO2 permeability of the oocyte to the same extent as does the wild-type channel. However, the C189S-dependent increase in CO2permeability is unaffected by treatment with PCMBS. These data rule out options 2–4 listed above. Thus our results suggest that CO2passes through the pore of AQP1 and are the first data to demonstrate that a gas can enter a cell by a means other than diffusing through the membrane lipid.

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Bicarbonate Recycling by HIF-1-Dependent Carbonic Anhydrase Isoforms 9 and 12 Is Critical in Maintaining Intracellular pH and Viability of Nucleus Pulposus Cells

Journal of Bone and Mineral Research ◽

10.1002/jbmr.3293 ◽

2017 ◽

Vol 33 (2) ◽

pp. 338-355 ◽

Cited By ~ 14

Author(s):

Elizabeth S Silagi ◽

Zachary R Schoepflin ◽

Erin L Seifert ◽

Christophe Merceron ◽

Ernestina Schipani ◽

...

Keyword(s):

Carbonic Anhydrase ◽

Nucleus Pulposus ◽

Intracellular Ph ◽

Nucleus Pulposus Cells

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Transgenic expression of carbonic anhydrase III in cardiac muscle demonstrates a mechanism to tolerate acidosis

AJP Cell Physiology ◽

10.1152/ajpcell.00130.2019 ◽

2019 ◽

Vol 317 (5) ◽

pp. C922-C931 ◽

Cited By ~ 2

Author(s):

Han-Zhong Feng ◽

J.-P. Jin

Keyword(s):

Carbonic Anhydrase ◽

Transgenic Mice ◽

Intracellular Ph ◽

Skeletal Muscles ◽

Ex Vivo ◽

Physiological Role ◽

Wild Type Mouse ◽

Carbonic Anhydrases ◽

Wild Type ◽

Carbonic Anhydrase Iii

Carbonic anhydrase III (CAIII) is abundant in liver, adipocytes, and skeletal muscles, but not heart. A cytosolic enzyme that catalyzes conversions between CO2 and [Formula: see text] in the regulation of intracellular pH, its physiological role in myocytes is not fully understood. Mouse skeletal muscles lacking CAIII showed lower intracellular pH during fatigue, suggesting its function in stress tolerance. We created transgenic mice expressing CAIII in cardiomyocytes that lack endogenous CAIII. The transgenic mice showed normal cardiac development and life span under nonstress conditions. Studies of ex vivo working hearts under normal and acidotic conditions demonstrated that the transgenic and wild-type mouse hearts had similar pumping functions under normal pH. At acidotic pH, however, CAIII transgenic mouse hearts showed significantly less decrease in cardiac function than that of wild-type control as shown by higher ventricular pressure development, systolic and diastolic velocities, and stroke volume via elongating the time of diastolic ejection. In addition to the effect of introducing CAIII into cardiomyocytes on maintaining homeostasis to counter acidotic stress, the results demonstrate the role of carbonic anhydrases in maintaining intracellular pH in muscle cells as a potential mechanism to treat heart failure.

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Synthesis and Evaluation of 1-hydroxybenzotriazole Derivatives: Dual Inhibitors of Carbonic Anhydrase II and Sodium Hydrogen Exchanger I

Letters in Organic Chemistry ◽

10.2174/1570178617999201014164710 ◽

2020 ◽

Vol 17 ◽

Author(s):

Dhandeep Singh ◽

Nirmal Singh

Keyword(s):

Carbonic Anhydrase ◽

Reperfusion Injury ◽

Intracellular Ph ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Carbonic Anhydrase Ii ◽

Dual Inhibitor ◽

Sodium Hydrogen ◽

Sodium Hydrogen Exchanger ◽

Dual Inhibitors

: Ischemia reperfusion injury is responsible for impaired graft functioning in organ transplants, cerebral dysfunction, ischemic heart diseases, systemic inflammatory response syndrome, gastrointestinal dysfunction, and multiple organ dysfunction syndromes. Intracellular pH is critical for cell survival in ischemia reperfusion injury. Sodium hydrogen exchanger I and carbonic anhydrase II are critical in regulation of intracellular pH. Inhibition of sodium hydrogen exchanger I and carbonic anhydrase II during reprfusion is found to ameliorate ischemia reperfusion injury separately. An attempt is made to synthesize dual inhibitors of sodium hydrogen exchanger and carbonic anhydrase to have better potential drug molecule in ischemia reperfusion injury treatment. The hydroxybenzotriazole is considered as a central pharmacophore for this dual activity and 12 derivatives are synthesized. All derivatives are tested for sodium hydrogen exchanger I and carbonic anhydrase II inhibitory activity. The tosylate derivative (12) is found to be the most potent derivative with IC50 158.7± 8.4 µM for carbonic anhydrase II and 31.07 ± 1.06 µM for sodium hydrogen exchanger I. Although the potency is less than standard drugs but this is the first report of dual inhibitor of carbonic anhydrase II and sodium hydrogen exchanger.

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Faculty Opinions recommendation of Hypoxia-inducible carbonic anhydrase IX and XII promote tumor cell growth by counteracting acidosis through the regulation of the intracellular pH.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1142907.599998 ◽

2009 ◽

Author(s):

Jeff Kraut

Keyword(s):

Cell Growth ◽

Carbonic Anhydrase ◽

Tumor Cell ◽

Intracellular Ph ◽

Carbonic Anhydrase Ix ◽

Tumor Cell Growth ◽

Promote Tumor Cell

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Does Aerobic Respiration Produce Carbon Dioxide or Hydrogen Ion and Bicarbonate?

Anesthesiology ◽

10.1097/aln.0000000000002125 ◽

2018 ◽

Vol 128 (5) ◽

pp. 873-879 ◽

Cited By ~ 2

Author(s):

Erik R. Swenson

Keyword(s):

Carbon Dioxide ◽

Carbonic Anhydrase ◽

Intracellular Ph ◽

Ph Regulation ◽

Krebs Cycle ◽

Brain Homogenate ◽

Hydrogen Ion ◽

Facilitated Diffusion ◽

Intracellular Acidosis ◽

End Products

Abstract Maintenance of intracellular pH is critical for clinical homeostasis. The metabolism of glucose, fatty acids, and amino acids yielding the generation of adenosine triphosphate in the mitochondria is accompanied by the production of acid in the Krebs cycle. Both the nature of this acidosis and the mechanism of its disposal have been argued by two investigators with a long-abiding interest in acid–base physiology. They offer different interpretations and views of the molecular mechanism of this intracellular pH regulation during normal metabolism. Dr. John Severinghaus has posited that hydrogen ion and bicarbonate are the direct end products in the Krebs cycle. In the late 1960s, he showed in brain and brain homogenate experiments that acetazolamide, a carbonic anhydrase inhibitor, reduces intracellular pH. This led him to conclude that hydrogen ion and bicarbonate are the end products, and the role of intracellular carbonic anhydrase is to rapidly generate diffusible carbon dioxide to minimize acidosis. Dr. Erik Swenson posits that carbon dioxide is a direct end product in the Krebs cycle, a more widely accepted view, and that acetazolamide prevents rapid intracellular bicarbonate formation, which can then codiffuse with carbon dioxide to the cell surface and there be reconverted for exit from the cell. Loss of this “facilitated diffusion of carbon dioxide” leads to intracellular acidosis as the still appreciable uncatalyzed rate of carbon dioxide hydration generates more protons. This review summarizes the available evidence and determines that resolution of this question will require more sophisticated measurements of intracellular pH with faster temporal resolution.

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