Specific monoclonal antibody-based immunotherapy by targeting the RCC-associated antigen carbonic anhydrase-IXG250/MN

Novel omics technology driving translational research in precision oncology

In this review, we summarize the current challenges faced by cancer researchers and motivate the use of novel genomics solutions. We follow this up with a comprehensive overview of three recent genomics technologies: liquid biopsy, single-cell RNA sequencing and spatial transcriptomics. We discuss a few representative protocols/assays for each technology along with their strengths, weaknesses, optimal use-cases, and their current stage of clinical deployment by summarizing trial data. We focus on how these technologies help us develop a better understanding of cancer as a rapidly evolving heterogeneous genetic disease that modulates its immediate microenvironment leading to systemic macro-level changes in the patient body. We summarize the review with a flowchart that integrates these three technologies in the existing workflows of clinicians and researchers toward robust detection, accurate diagnosis, and precision oncology.

Biophysical, Biochemical, and Cell Based Approaches Used to Decipher the Role of Carbonic Anhydrases in Cancer and to Evaluate the Potency of Targeted Inhibitors

Carbonic anhydrases (CAs) are thought to be important for regulating pH in the tumor microenvironment. A few of the CA isoforms are upregulated in cancer cells, with only limited expression in normal cells. For these reasons, there is interest in developing inhibitors that target these tumor-associated CA isoforms, with increased efficacy but limited nonspecific cytotoxicity. Here we present some of the biophysical, biochemical, and cell based techniques and approaches that can be used to evaluate the potency of CA targeted inhibitors and decipher the role of CAs in tumorigenesis, cancer progression, and metastatic processes. These techniques include esterase activity assays, stop flow kinetics, and mass inlet mass spectroscopy (MIMS), all of which measure enzymatic activity of purified protein, in the presence or absence of inhibitors. Also discussed is the application of X-ray crystallography and Cryo-EM as well as other structure-based techniques and thermal shift assays to the studies of CA structure and function. Further, large-scale genomic and proteomic analytical methods, as well as cell based techniques like those that measure cell growth, apoptosis, clonogenicity, and cell migration and invasion, are discussed. We conclude by reviewing approaches that test the metastatic potential of CAs and how the aforementioned techniques have contributed to the field of CA cancer research.

Carbonic Anhydrases: Role in pH Control and Cancer

The pH of the tumor microenvironment drives the metastatic phenotype and chemotherapeutic resistance of tumors. Understanding the mechanisms underlying this pH-dependent phenomenon will lead to improved drug delivery and allow the identification of new therapeutic targets. This includes an understanding of the role pH plays in primary tumor cells, and the regulatory factors that permit cancer cells to thrive. Over the last decade, carbonic anhydrases (CAs) have been shown to be important mediators of tumor cell pH by modulating the bicarbonate and proton concentrations for cell survival and proliferation. This has prompted an effort to inhibit specific CA isoforms, as an anti-cancer therapeutic strategy. Of the 12 active CA isoforms, two, CA IX and XII, have been considered anti-cancer targets. However, other CA isoforms also show similar activity and tissue distribution in cancers and have not been considered as therapeutic targets for cancer treatment. In this review, we consider all the CA isoforms and their possible role in tumors and their potential as targets for cancer therapy.

Advances in Anti-Cancer Drug Development Targeting Carbonic Anhydrase IX and XII

The microenvironment within a solid tumor is heterogeneous with regions being both acidic and hypoxic. As a result of this, cancer cells upregulate genes that allow survival in such environments. Some of these genes are pH regulatory factors, including carbonic anhydrase IX (CA IX) and in some cases XII (CA XII). CA IX helps to maintain normal cytoplasmic pH (pHi) while simultaneously contributing to the extracellular pH (pHe). CA XII is also thought to be responsible for stabilizing pHe at physiological conditions. Extracellular acidification of the tumor microenvironment promotes local invasion and metastasis while decreasing the effectiveness of adjuvant therapies, thus contributing to poor cancer clinical outcomes. In this review, we describe the properties of CA IX and CA XII that substantiate their potential use as anticancer targets. We also discuss the current status of CA isoform-selective inhibitor development and patents of CA IX/XII targeted inhibitors that show potential for treating aggressive tumors. Some of the recently published patents discussed include sulfonamide-based small molecule inhibitors including derivatives of boron cluster compounds; metal complexes of poly(carboxyl)amine-containing ligands; nitroi-midazole-, ureidosulfonamide-, and coumarin-based compounds; as well as G250 and A610 monoclonal antibodies for cancer treatment.

Overexpression of carbonic anhydrase IX (CAIX) is an independent unfavorable prognostic marker in endometrioid ovarian cancer

Carbonic anhydrase IX (CAIX) is a strictly membranous expressed metalloenzyme involved in cell adhesion, pH homeostasis, and cancer progression. This study was designed to assess the role of CAIX in primary ovarian cancer. Two hundred five well-characterized primary ovarian carcinomas were analyzed on a tissue microarray. CAIX expression was determined by immunohistochemistry using a four-step scoring system. Moderate and strong membranous CAIX expression was found in 37 out of 205 (18%) of all assessable ovarian cancer specimens. High levels of CAIX expression were related to mucinous and endometrioid phenotype of ovarian carcinomas (p < 0.05). There was no association between CAIX overexpression and tumor stage, grading, and mitotic count of ovarian carcinomas (p > 0.05). In univariate Cox regression analysis, advanced tumor stage (p < 0.01), high tumor grade (p = 0.017), high mitotic count (p = 0.025), and high CAIX expression levels (p = 0.031) were correlated to shorter overall patient survival. High pT stage (p = 0.036) and CAIX overexpression were connected to poor clinical outcome in endometrioid ovarian carcinomas. Multivariate Cox regression hazard analysis comprising tumor stage, tumor grade, mitotic count, and CAIX expression revealed pT2/3 stage and CAIX overexpression (scores 2 and 3) as independent prognostic markers in ovarian cancer (p < 0.01, each) as well as in the subgroup of endometrioid carcinomas (p < 0.05, each). In conclusion, CAIX is overexpressed in a substantial proportion of mucinous and endometrioid ovarian carcinomas and connected to poor patient outcome. Our data support the potential therapeutic benefit of newly developed targeting antibodies in advanced ovarian cancer.

Overexpression of carbonic anhydrase IX (CAIX) in vulvar cancer is associated with tumor progression and development of locoregional lymph node metastases

Carbonic anhydrase IX (CAIX) is a strictly membranous expressed metalloenzyme involved in cell adhesion, pH homeostasis, and cancer progression. The protein is specifically overexpressed in a wide variety of malignant tumors. This study was designed to assess the role of CAIX in primary vulvar cancer. One hundred forty-two well-characterized primary vulvar carcinomas were analyzed on a tissue microarray (TMA). Three tissue cores were sampled from each tumor. CAIX expression was determined by immunohistochemistry, using a four-step scoring system. To determine CAIX expression in benign vulvar tissue, we constructed a TMA with 120 samples of normal mucosa and non-neoplastic diseases. CAIX expression was found in 77/135 (57%) of all assessable vulvar cancer specimens and 48 (35.5%) exhibited a moderate or strong expression. CAIX expression in vulvar carcinomas was significantly stronger compared to non-neoplastic vulvar tissue (p < 0.001). High levels of CAIX expression were related to pT stage (p < 0.01), tumor size (p < 0.01), depth of invasion (p < 0.05), as well as inguinal lymph node metastases (p < 0.05). There was also a trend towards shorter recurrence-free patient survival in CAIX-positive compared to CAIX-negative vulvar cancers. CAIX staining results in different tissue cores from the same tumor were homogeneous, raising the possibility of a hypoxia-independent expression. In conclusion, CAIX is overexpressed in the majority of vulvar carcinomas with relationships to advanced tumor stages and development of lymph node metastases. Our data support the potential therapeutic benefit of newly developed targeting antibodies in advanced vulvar cancer.

Serum carbonic anhydrase IX during first-line therapy of ovarian cancer

OBJECTIVE

Carbonic anhydrase IX (CAIX) is primarily involved in maintaining the extracellular pH. It is overexpressed in a variety of tumors including ovarian cancer. To evaluate the potential prognostic and predictive role of serum CAIX for therapy response in ovarian cancer, we analyzed longitudinal serum samples.

METHODS

One hundred forty-eight serum samples from 37 patients with primary epithelial ovarian cancer were analyzed. Samples were prospectively collected at 4 time points: (1) before radical surgery, (2) after surgery and before platinum/taxane chemotherapy, (3) during chemotherapy, and (4) after chemotherapy. Serum CAIX was quantified by ELISA and expression in tumor tissue was verified by immunohistochemistry. Correlation with response and clinical outcome as well as the tumor marker CA-125 was analyzed.

RESULTS

Serum concentration of CAIX ranged between 30 and 1687 pg/mL and showed no significant changes during first-line therapy (median level before and after surgery 204 and 198 pg/mL, during and after chemotherapy 175 and 181 pg/mL). There was no association between serum CAIX and progression-free or overall survival. CA-125 decreased significantly after surgery (median serum level before and after surgery 413 and 84 kU/L, p<0.001) and further during and after first-line chemotherapy (median serum levels 21 and 15 kU/L, p<0.001). No intermarker correlation was observed.

CONCLUSIONS

CAIX is upregulated in ovarian cancer and serum CAIX could be a marker to stratify patients for therapy response. However, CAIX serum levels did not change significantly during first-line therapy and were not prognostically relevant. Based on the findings of the current study, CAIX cannot be recommended for therapy monitoring in this context.

Biomarkers in renal cell carcinoma

PURPOSE OF REVIEW

To review the latest information on biomarkers in renal cell carcinoma and their use in integrated staging systems.

RECENT FINDINGS

The discovery of the Von Hippel-Lindau defect and the hypoxia inducible factor-1alpha transcripted genes has led to an explosion in the understanding of molecular pathways in renal cell carcinoma. The two most prominent biomarkers are carbonic anhydrase IX and vascular endothelial-derived growth factor. Carbonic anhydrase IX has demonstrated excellent specificity and ability to predict treatment response. Vascular-derived growth factor has good correlation with stage, grade and increased levels with adverse survival. Markers such as CXCL16, ADAM10, B7-H1, Ki-67, survivin, P53, GLUT-1, calveolin-1 and endoglin are continuously being validated. CXCL16 is one of the newest biomarkers, is significantly expressed in papillary renal cell carcinoma and is an independent prognostic marker for better patient survival. The incorporation of biomarkers into integrated staging systems such as UCLA Integrated Staging System, SSIGN and Bioscore are discussed and compared.

SUMMARY

The use of novel molecular biomarkers are being incorporated into clinical practice. The understanding of molecular pathways will lead to tailored treatment to the individual patient.

Challenges of cancer biomarker profiling

OBJECTIVES

New biomarkers are being developed to identify individuals at risk for cancer, detect disease earlier, determine prognosis, detect recurrence, predict response to particular agents, and monitor response to treatment. This article attempts to address some of the challenges facing the research and medical communities in the delivery of new biomarkers for individualized medicine.

METHODS

A variety of issues and barriers can affect the transfer of clinical tests from research to clinical practice. Differences in sample collection, handling or storage, and profiling techniques may influence the protein profile obtained by any method.

RESULTS

Standard procedures and quality check schemes are necessary because there is a lack of definition to guarantee reproducibility of new procedures. From technical and economic viewpoints, the assay has to be sufficiently robust to be completed in community-based hospitals. Although traditionally cancer patients were treated with drugs of low toxicity or of high tolerance regardless of their efficacy in a given patient if the benefits of that drug are proven in both experimental and clinical conditions, recent advances have provided opportunities to adapt "tailored" treatment modalities. The evolving trend is the usage of patterns of markers instead of a single marker. Further challenges in biomarker development are in finding the relevant markers that have the right degree of specificity and sensitivity and a reliable test to measure the outcome.

CONCLUSIONS

Discovery, testing, and validation of clinically appropriate and commercially useful tumor markers should permit individualization of therapy.

Expression of transmembrane carbonic anhydrases IX and XII in ovarian tumours

AIMS

Carbonic anhydrase (CA) isozymes IX and XII have been suggested to play a role in oncogenic processes. The aim of the present study was to investigate CA IX and XII expression in patients with ovarian tumours.

METHODS AND RESULTS

A series of ovarian tumours was immunostained for CA IX and XII and the results were correlated with histopathological and clinical parameters. Most cases of borderline mucinous cystadenomas, mucinous cystadenocarcinomas and serous cystadenocarcinomas were moderately or strongly positive for CA IX. In malignant tumours, the staining was most prominent in hypoxic regions. Expression of CA XII was detected in all tumour categories, although the mean staining intensity was weaker than for CA IX in all groups except for clear cell carcinomas.

CONCLUSIONS

The wide expression of CA IX and XII in ovarian tumours suggests that these isozymes could represent potential targets in ovarian cancer therapy. The expression pattern of CA IX suggests that it could also serve as a useful histopathological marker protein for hypoxia in malignant ovarian tumours.