Carbonic anhydrase IX (CAIX) is a hypoxia-inducible enzyme that is overexpressed by cancer cells from many tumor types, and is a component of the pH regulatory system invoked by these cells to combat the deleterious effects of a high rate of glycolytic metabolism. CAIX functions to help produce and maintain an intracellular pH (pHi) favorable for tumor cell growth and survival, while at the same time participating in the generation of an increasingly acidic extracellular space, facilitating tumor cell invasiveness. Pharmacologic interference of CAIX catalytic activity using monoclonal antibodies or CAIX-specific small molecule inhibitors, consequently disrupting pH regulation by cancer cells, has been shown recently to impair primary tumor growth and metastasis. Many of these agents are in preclinical or clinical development and constitute a novel, targeted strategy for cancer therapy.

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Recent developments in targeting carbonic anhydrase IX for cancer therapeutics.

Carbonic anhydrase IX interacts with bicarbonate transporters in lamellipodia and increases cell migration via its catalytic domain

Preface. Part I Introduction. 1 Overview of the Carbonic Anhydrase Field. Part II Carbonic Anhydrases: Ancient but Relevant. Physiological Functions of the Alpha Class of Carbonic Anhydrases. 3 Catalytic Mechanism of alpha-Class Carbonic Anhydrases: CO2 Hydration and Proton Transfer. 4 Structure and Catalytic Mechanism of b-Carbonic Anhydrases. 5 Prokaryotic Carbonic Anhydrases of Earth's Environment. 6 Carboxysomal Carbonic Anhydrases. 7 Carbonic Anhydrases and their Interplay with Acid/base-coupled Membrane Transporters. 8 Carbonic Anhydrase Related Proteins: Molecular Biology and Evolution. 9 Membrane Associated Carbonic Anhydrase IV (CA IV): A Personal and Historical Perspective. 10 Carbonic Anhydrase Expression in Kidney and Renal Cancer: Implications for Diagnosis and Treatment. 11 Carbonic Anhydrase IX: Regulation and Role in Cancer. 12 Carbonic Anhydrase IX as an Imaging and Therapeutic Target for Tumors and Metastases. 13 Carbonic Anhydrase IX (CAIX) as a Mediator of Hypoxia-induced Stress Response in Cancer Cells. 14 Carbonic Anhydrases and Brain pH in the Control of Neruronal Excitability. 15 Carbonic Anhydrase Inhibitors: Drug Design. 16 Natural Products that Inhibit Carbonic Anhydrases. 17 Glaucoma and the Application of Carbonic Anhydrase Inhibitors. 18 Carbonic Anhydrase Inhibitors and High Altitude Illnesses. 19 Thermal-Stable Carbonic Anhydrases: A Structural Overview. 20 Carbonic Anhydrases in Industrial Applications. Index.

Carbonic anhydrase: mechanism, regulation, links to disease, and industrial applications

Hypoxia is a characteristic of many solid tumors and an adverse prognostic factor for treatment outcome. Hypoxia increases the expression of carbonic anhydrase IX (CAIX), an enzyme that is predominantly found on tumor cells and is involved in maintaining the cellular pH balance. Many clinical studies investigated the prognostic value of CAIX expression, but most have been inconclusive, partly due to small numbers of patients included. The present meta-analysis was therefore performed utilizing the results of all clinical studies to determine the prognostic value of CAIX expression in solid tumors. Renal cell carcinoma was excluded from this meta-analysis due to an alternative mechanism of upregulation. 958 papers were identified from a literature search performed in PubMed and Embase. These papers were independently evaluated by two reviewers and 147 studies were included in the analysis. The meta-analysis revealed strong significant associations between CAIX expression and all endpoints: overall survival [hazard ratio (HR) = 1.76, 95% confidence interval (95%CI) 1.58–1.98], disease-free survival (HR = 1.87, 95%CI 1.62–2.16), locoregional control (HR = 1.54, 95%CI 1.22–1.93), disease-specific survival (HR = 1.78, 95%CI 1.41–2.25), metastasis-free survival (HR = 1.82, 95%CI 1.33–2.50), and progression-free survival (HR = 1.58, 95%CI 1.27–1.96). Subgroup analyses revealed similar associations in the majority of tumor sites and types. In conclusion, these results show that patients having tumors with high CAIX expression have higher risk of locoregional failure, disease progression, and higher risk to develop metastases, independent of tumor type or site. The results of this meta-analysis further support the development of a clinical test to determine patient prognosis based on CAIX expression and may have important implications for the development of new treatment strategies.

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Prognostic Significance of Carbonic Anhydrase IX Expression in Cancer Patients: A Meta-Analysis.

BACKGROUND\nCervical carcinoma is a leading cause of mortality from cancer among women worldwide, accounting for approximately 160,000 deaths annually. Prognosis in patients with this disease is dependent on several well-established clinical features (stage of disease and age of patient) and pathologic features (lymph node status, grade of tumor, and depth of invasion). Although the features associated with poor clinical outcome have been well studied, molecular markers such as human papillomavirus (HPV) type that may reflect the underlying biologic basis for clinical behavior are poorly understood.\n\n\nPURPOSE\nTo test the hypothesis that differences in survival among patients with cervical carcinoma are associated with HPV DNA type, we conducted a historical cohort study of patients treated at our institutions over a 10-year period.\n\n\nMETHODS\nFresh primary tumor tissue samples from 291 women with all stages of cervical carcinoma diagnosed from April 1983 through August 1993 were rapidly frozen and stored at -70 degrees C until analysis. High-molecular-weight DNA was extracted and purified by homogenization, proteinase K digestion, phenol extraction, ammonium acetate salt displacement, ethanol precipitation, and ribonuclease treatment. HPV nucleotide sequences were amplified from tumor DNA samples by polymerase chain reaction with the use of both consensus L1 (MY09/MY11) primers that recognize more than 25 HPV types and modifications of type-specific primers developed for HPV types 16, 18, and 6. Clinical data were abstracted from hospital, office, and tumor registry records. Univariate analysis was conducted using Student's t test and chi-squared tests. Survival curves were estimated by use of the Kaplan-Meier method; differences between groups were examined by the logrank test. Multivariate survival analysis was performed according to the Cox proportional hazards model.\n\n\nRESULTS\nHPV DNA was detected in 247 (85%) of 291 tumors: HPV16 in 52%, HPV18 in 20%, other HPV types in 13%, and no HPV DNA in 15%. Eighty-eight percent of squamous tumors contained HPV DNA compared with 79% of adenocarcinomas, the latter harboring predominantly HPV18. Women 45 years old or younger with a history of cigarette smoking tended to have HPV DNA in their tumors, but the HPV type was not associated with established prognostic factors such as stage, grade, lymph node metastasis, or depth of stromal invasion. After a median follow-up of 38.9 months, among potential prognostic factors of patient age, histologic cell type, grade, and HPV DNA status, only stage was predictive of survival in the entire study population. However, among the 171 patients treated with type III radical hysterectomy (removal of uterus and upper vagina along with other tissues extending to the pelvic wall) and pelvic lymphadenectomy (removal of all lymphatic tissue in the pelvis), multivariate analysis determined that lymph node status (adjusted risk ratio [RR] = 3.12; 95% confidence interval [CI] = 1.35-7.21), depth of stromal invasion (adjusted RR = 3.14; 95% Cl = 1.05-9.34), and the presence of HPV18 DNA (adjusted RR = 2.59; 95% CI = 1.08-6.22) were statistically significant predictors of survival.\n\n\nCONCLUSION\nHPV18 DNA type is an independent prognostic factor in patients with cervical carcinomas treated with radical hysterectomy and pelvic lymphadenectomy.\n\n\nIMPLICATIONS\nThe use of molecular markers such as HPV DNA type may allow the identification of patients with early stage cervical cancer at high risk for disease recurrence.

Human Papillomavirus Type 18: Association with Poor Prognosis in Early Stage Cervical Cancer

Carbonic anhydrase IX (CAIX) is a membranous expressed metalloenzyme involved in pH homeostasis and cell adhesion. The protein is overexpressed in a variety of tumors and potentially associated with negative outcome. This study was designed to investigate the prognostic role of CAIX in serum and tumor tissue of patients with primary cervical cancer. Tumor samples of 221 consecutive patients with primary cervical cancer who underwent surgery between 1993 and 2008 were analyzed for CAIX expression by immunohistochemistry. Additionally, preoperative serum CAIX concentrations were determined by ELISA in a subset of patients. Correlation with intratumoral CAIX expression as well as clinicopathological factors and outcome was analyzed. CAIX expression was observed in 81.9% of the tumor specimens; 62.0% showed a moderate or strong staining intensity. Moderate/strong expression was associated with squamous histology (p = 0.024), advanced tumor stage (p = 0.001), greater invasion depth (p = 0.025), undifferentiated tumor grade (p < 0.001) and high preoperative SCC-Ag values (p = 0.042). Furthermore patients with moderate/strong intratumoral CAIX expression had a higher number of metastatic lymph nodes compared to those with none/weak intratumoral expression levels (p = 0.047) and there was a non-significant association between high intratumoral CAIX expression and shorter survival (p = 0.118). Preoperative serum concentrations of CAIX ranged between 23 and 499 pg/mL and did not correlate with intratumoral expression or other clinicopathological variables. CAIX is associated with advanced tumor stages and lymph node metastases in cervical cancer, potentially representing a new target in this disease. In contrast to other epithelial cancers we could not observe a correlation between serum CAIX and its intratumoral expression.

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Carbonic anhydrase IX in tumor tissue and sera of patients with primary cervical cancer

Background
An altered expression of the activated leukocyte cell adhesion molecule (ALCAM) is associated with cancer progression in various cancer types. In some cancers ALCAM has a prognostic value or is predictive for the benefit of therapeutic interventions. To date there are no data on the role of ALCAM in cervical cancer available.

https://link.springer.com/content/pdf/10.1186%2F1471-2407-12-140.pdf

Relevance of activated leukocyte cell adhesion molecule (ALCAM) in tumor tissue and sera of cervical cancer patients

Human saliva contains a plethora of proteins whose presence and concentration can be monitored for diagnosis and progression of disease. Saliva has been extensively probed for the diagnosis of several systemic and infectious diseases because of the ease with which it can be collected. However, amylase, the most abundant protein found in saliva can obscure the detection of low-abundance proteins by MALDI-ToF MS (matrix-assisted laser desorption/ionization-time of flight mass spectrometry) and diminish the diagnostic utility of this specimen type. In the present study, we used a device to deplete salivary amylase from water-gargle samples through affinity adsorption. After depletion, profiling of the saliva proteome was performed by MALDI-ToF MS on gargle samples from subjects whose COVID-19 (coronavirus disease 2019) status was confirmed by NP (nasopharyngeal) swab RT-qPCR (reverse transcription polymerase chain reaction). Amylase depletion led to the enhancement of signal intensities of various peaks as well as the detection of previously unobserved peaks in the MALDI-ToF spectra. The overall specificity and sensitivity after amylase depletion was 100% and 85.17% respectively for detecting COVID-19. Our simple, rapid and inexpensive technique to deplete salivary amylase can be used to unmask spectral diversity in saliva by MALDI-ToF MS, reveal low-abundant proteins and aid in the establishment of novel biomarkers for diseases.

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Kerstin Kress

Papers

Carbonic anhydrase IX in tumor tissue and sera of patients with primary cervical cancer

Relevance of activated leukocyte cell adhesion molecule (ALCAM) in tumor tissue and sera of cervical cancer patients

Amylase depletion significantly improves the maldi-tof profile of saliva-application to covid-19 diagnostics