The proteoglycan region of the tumor-associated carbonic anhydrase isoform IX acts as anintrinsic buffer optimizing CO2 hydration at acidic pH values characteristic of solid tumors

2009 ◽  
Vol 19 (20) ◽  
pp. 5825-5828 ◽  
Author(s):  
Alessio Innocenti ◽  
Silvia Pastorekova ◽  
Jaromir Pastorek ◽  
Andrea Scozzafava ◽  
Giuseppina De Simone ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Solid Tumors ◽  
Acidic Ph ◽  
Ph Values

scholarly journals Targeting ion transport in cancer

2014 ◽  
Vol 369 (1638) ◽  
pp. 20130107 ◽  
Author(s):  
E. Oosterwijk ◽  
R. J. Gillies
Keyword(s):  
Carbonic Anhydrase ◽  
Ion Transport ◽  
Ph Regulation ◽  
Acidic Ph ◽  
Ion Transporters ◽  
Normal Cells ◽  
Normal Tissues ◽  
Ph Values ◽  
Normal Limits ◽  
Important Therapeutic Target

The metabolism of cancer cells differs substantially from normal cells, including ion transport. Although this phenomenon has been long recognized, ion transporters have not been viewed as suitable therapeutic targets. However, the acidic pH values present in tumours which are well outside of normal limits are now becoming recognized as an important therapeutic target. Carbonic anhydrase IX (CAIX) is fundamental to tumour pH regulation. CAIX is commonly expressed in cancer, but lowly expressed in normal tissues and that presents an attractive target. Here, we discuss the possibilities of exploiting the acidic, hypoxic tumour environment as possible target for therapy. Additionally, clinical experience with CAIX targeting in cancer patients is discussed.

Is the Acidic pH of the External Auditory Canal Playing a Significant Role in the Treatment of Acute Otitis Externa?

2018 ◽  
Vol 69 (8) ◽  
pp. 2304-2305
Author(s):  
Oana Ruxandra Iana ◽  
Dragos Cristian Stefanescu ◽  
Viorel Zainea ◽  
Razvan Hainarosie
Keyword(s):  
External Auditory Canal ◽  
Otitis Externa ◽  
Proton Pumps ◽  
Acidic Ph ◽  
External Ear ◽  
Ph Values ◽  
The World ◽  
Subcutaneous Tissues ◽  
Low Levels ◽  
Value Changes

Variable pH values for skin have been reported in the literature, all within the acidic range, varying from 4.0 up to 7. 0. The origin of the acidic pH remains conjectural, and several factors have been incriminated with this role, such as eccrine and sebaceous secretions as well as proton pumps. Keeping low levels of pH prevents microbial dispersal as well as multiplication. The skin in the external auditory canal is also covered with this acidic mantle with antimicrobial value. Changes of pH in the external ear can lead to acute otitis externa. This condition is defined by the inflammation and infection of the cutaneous and subcutaneous tissues of the external auditory canal. 10% of the world�s population may suffer from acute otitis externa at least once in their lifetime. This paper aims to consolidate the relevance of an acidic pH in the healthy external ear and its relation to the pathogenesis and treatment of otitis externa through a prospective and interventional clinical study on 80 patients who presented to the outpatient department at Prof. Dr D. Hociota ENT Institute in Buch

scholarly journals In Vitro Incorporation of Helicobacter pylori into Candida albicans Caused by Acidic pH Stress

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 489 ◽  
Author(s):  
Kimberly Sánchez-Alonzo ◽  
Cristian Parra-Sepúlveda ◽  
Samuel Vega ◽  
Humberto Bernasconi ◽  
Víctor L. Campos ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Candida Albicans ◽  
Pcr Amplification ◽  
Growth Curves ◽  
Acidic Ph ◽  
Ph Values ◽  
16S Gene ◽  
Wide Range ◽  
H Pylori

Yeasts can adapt to a wide range of pH fluctuations (2 to 10), while Helicobacter pylori, a facultative intracellular bacterium, can adapt to a range from pH 6 to 8. This work analyzed if H. pylori J99 can protect itself from acidic pH by entering into Candida albicans ATCC 90028. Growth curves were determined for H. pylori and C. albicans at pH 3, 4, and 7. Both microorganisms were co-incubated at the same pH values, and the presence of intra-yeast bacteria was evaluated. Intra-yeast bacteria-like bodies were detected using wet mounting, and intra-yeast binding of anti-H. pylori antibodies was detected using immunofluorescence. The presence of the H. pylori rDNA 16S gene in total DNA from yeasts was demonstrated after PCR amplification. H. pylori showed larger death percentages at pH 3 and 4 than at pH 7. On the contrary, the viability of the yeast was not affected by any of the pHs evaluated. H. pylori entered into C. albicans at all the pH values assayed but to a greater extent at unfavorable pH values (pH 3 or 4, p = 0.014 and p = 0.001, respectively). In conclusion, it is possible to suggest that H. pylori can shelter itself within C. albicans under unfavorable pH conditions.

A dual-mode colorimetric/fluorescent probe based on perylene: Response to acidic pH values

2021 ◽  
Author(s):  
Liu Yang ◽  
Yan Liu ◽  
Ping Li ◽  
Yu-Long Liu ◽  
Xiao-Min Liang ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Acidic Ph ◽  
Dual Mode ◽  
Ph Values

Orthorhombic lysozyme crystallization at acidic pH values driven by phosphate binding

2018 ◽  
Vol 74 (5) ◽  
pp. 480-489 ◽  
Author(s):  
Marina Plaza-Garrido ◽  
M. Carmen Salinas-Garcia ◽  
Ana Camara-Artigas
Keyword(s):  
Conformational Changes ◽  
Protein Function ◽  
Protein Crystallization ◽  
Amyloid Formation ◽  
Acidic Ph ◽  
Phosphate Binding ◽  
Cell Parameters ◽  
Ph Values ◽  
Phosphate Ion ◽  
Α Helix

The structure of orthorhombic lysozyme has been obtained at 298 K and pH 4.5 using sodium chloride as the precipitant and in the presence of sodium phosphate at a concentration as low as 5 mM. Crystals belonging to space groupP212121(unit-cell parametersa= 30,b= 56,c= 73 Å, α = β = γ = 90.00°) diffracted to a resolution higher than 1 Å, and the high quality of these crystals permitted the identification of a phosphate ion bound to Arg14 and His15. The binding of this ion produces long-range conformational changes affecting the loop containing Ser60–Asn74. The negatively charged phosphate ion shields the electrostatic repulsion of the positively charged arginine and histidine residues, resulting in higher stability of the phosphate-bound lysozyme. Additionally, a low-humidity orthorhombic variant was obtained at pH 4.5, and comparison with those previously obtained at pH 6.5 and 9.5 shows a 1.5 Å displacement of the fifth α-helix towards the active-site cavity, which might be relevant to protein function. Since lysozyme is broadly used as a model protein in studies related to protein crystallization and amyloid formation, these results indicate that the interaction of some anions must be considered when analysing experiments performed at acidic pH values.

scholarly journals Inactivation of tyrosine aminotransferase in neutral homogenates and rat liver slices

1972 ◽  
Vol 129 (5) ◽  
pp. 1131-1138 ◽  
Author(s):  
F. Auricchio ◽  
L. Mollica ◽  
A. Liguori
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Acid Concentration ◽  
Tyrosine Aminotransferase ◽  
Amino Acid Concentration ◽  
Acidic Ph ◽  
Ph Values ◽  
Neutral Ph ◽  
Liver Slices

Inactivation of tyrosine aminotransferase induced in vivo by triamcinolone was studied in a homogenate incubated at neutral pH values. The integrity and the presence of subcellular particles together with a compartment of acidic pH are necessary for inactivation of tyrosine aminotransferase. It is suggested that tyrosine aminotransferase is inactivated inside lysosomes. The system responsible for inactivation of tyrosine aminotransferase was partially purified and identified with lysosomal cathepsins B and B1. Inactivation of tyrosine aminotransferase in liver slices is controlled by the amino acid concentration and strongly stimulated by cysteine. 3,3′,5-Tri-iodo-l-thyronine reversibly and strongly decreases the rate of inactivation of tyrosine aminotransferase. The effect is not due to an increased rate of tyrosine aminotransferase synthesis.

Dual sensing of glutathione and acidic pH values by using MnO2 nanosheets and 3-acetyl-7-hydroxy-2H-chromen-2-one as a fluorescent pH probe

2019 ◽  
Vol 186 (8) ◽  
Author(s):  
Lei Fu ◽  
Yanlin Du ◽  
Zhenxi Zhang ◽  
Haiyan Sun ◽  
Aixian Zheng ◽  
...  
Keyword(s):  
Acidic Ph ◽  
Mno2 Nanosheets ◽  
Ph Probe ◽  
Ph Values ◽  
Dual Sensing

scholarly journals A Phase 1 Study of SLC-0111, a Novel Inhibitor of Carbonic Anhydrase IX, in Patients With Advanced Solid Tumors

2020 ◽  
Vol 43 (7) ◽  
pp. 484-490 ◽  
Author(s):  
Paul C. McDonald ◽  
Stephen Chia ◽  
Philippe L. Bedard ◽  
Quincy Chu ◽  
Michael Lyle ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Solid Tumors ◽  
Phase 1 ◽  
Carbonic Anhydrase Ix ◽  
Advanced Solid Tumors ◽  
Phase 1 Study

scholarly journals Personalized Treatment Response Assessment for Rare Childhood Tumors Using Microcalorimetry–Exemplified by Use of Carbonic Anhydrase IX and Aquaporin 1 Inhibitors

2019 ◽  
Vol 20 (20) ◽  
pp. 4984 ◽  
Author(s):  
Stephanie J. Gros ◽  
Stefan G. Holland-Cunz ◽  
Claudiu T. Supuran ◽  
Olivier Braissant
Keyword(s):  
Carbonic Anhydrase ◽  
Solid Tumors ◽  
Drug Response ◽  
Response Assessment ◽  
Carbonic Anhydrase Ix ◽  
Slice Culture ◽  
Treatment Concept ◽  
Aquaporin 1 ◽  
Novel Approach ◽  
Small Patient Population

We present a novel approach to a personalized therapeutic concept for solid tumors. We illustrate this on a rare childhood tumor for which only a generalized treatment concept exists using carbonic anhydrase IX and aquaporin 1 inhibitors. The use of microcalorimetry as a refined in vitro method for evaluation of drug susceptibility in organotypic slice culture has not previously been established. Rapid microcalorimetric drug response assessment can refine a general treatment concept when it is applied in cases in which tumors do not respond to conventional chemo-radiation treatment. For solid tumors, which do not respond to classical treatment, and especially for rare tumors without an established protocol rapid microcalorimetric drug response testing presents an elegant novel approach to test alternative therapeutic approaches. While improved treatment concepts have led to improved outcome over the past decades, the prognosis of high risk disease is still poor and rethinking of clinical trial design is necessary. A small patient population combined with the necessity to assess experimental therapies for rare solid tumors rather at the time of diagnosis than in relapsed or refractory patients provides great challenges. The possibility to rapidly compare established protocols with innovative therapeutics presents an elegant novel approach to refine and personalize treatment.

scholarly journals PHR2 of Candida albicans encodes a functional homolog of the pH-regulated gene PHR1 with an inverted pattern of pH-dependent expression.

1997 ◽  
Vol 17 (10) ◽  
pp. 5960-5967 ◽  
Author(s):  
F A Mühlschlegel ◽  
W A Fonzi
Keyword(s):  
Candida Albicans ◽  
Mutant Strain ◽  
Low Ph ◽  
Predicted Amino Acid Sequence ◽  
Acidic Ph ◽  
Null Mutant ◽  
Alkaline Ph ◽  
Ph Values ◽  
Functional Homolog ◽  
Morphological Defects

Deletion of PHR1, a pH-regulated gene of Candida albicans, results in pH-conditional defects in growth, morphogenesis, and virulence evident at neutral to alkaline pH but absent at acidic pH. Consequently, we searched for a functional homolog of PHR1 active at low pH. This resulted in the isolation of a second pH-regulated gene, designated PHR2. The expression of PHR2 was inversely related to that of PHR1, being repressed at pH values above 6 and progressively induced at more acidic pH values. The predicted amino acid sequence of the PHR2 protein, Phr2p, was 54% identical to that of Phr1p. A PHR2 null mutant exhibited pH-conditional defects in growth and morphogenesis analogous to those of PHR1 mutants but manifest at acid rather than alkaline pH values. Engineered expression of PHR1 at acid pH in a PHR2 mutant strain and PHR2 at alkaline pH in a PHR1 mutant strain complemented the defects in the opposing mutant. Deletion of both PHR1 and PHR2 resulted in a strain with pH-independent, constitutive growth and morphological defects. These results indicate that PHR1 and PHR2 represent a novel pH-balanced system of functional homologs required for C. albicans to adapt to environments of diverse pH.

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