Carbonic Anhydrase IX Research Articles

Disruption of the Physical Interaction Between Carbonic Anhydrase IX and the Monocarboxylate Transporter 4 Impacts Lactate Transport in Breast Cancer Cells

It has been previously established that breast cancer cells exhibit high expression of the monocarboxylate (lactate) transporters (MCT1 and/or MCT4) and carbonic anhydrase IX (CAIX) and form a functional metabolon for proton-coupled lactate export, thereby stabilizing intracellular pH. CD147 is the MCT accessory protein that facilitates the creation of the MCT/CAIX complex. This study describes how the small molecule Beta-Galactose 2C (BGal2C) blocks the physical and functional interaction between CAIX and either MCT1 or MCT4 in Xenopus oocytes, which reduces the rate of proton and lactate flux with an IC50 of ~90 nM. This value is similar to the Ki for inhibition of CAIX activity. Furthermore, it is shown that BGal2C blocks hypoxia-induced lactate transport in MDA-MB-231 and MCF-7 breast cancer cells, both of which express CAIX. As in oocytes, BGal2C interferes with the physical interaction between CAIX and MCTs in both cell types. Finally, X-ray crystallographic studies highlight unique interactions between BGal2C and a CAIX-mimic that are not observed within the CAII active site and which may underlie the strong specificity of BGal2C for CAIX. These studies demonstrate the utility of a novel sulfonamide in interfering with elevated proton and lactate flux, a hallmark of many solid tumors.

Impact of CA9 expression in the diagnosis of lymph-node metastases in non-small cell lung cancer based on [18F]FDG PET/CT.

Lung cancer is the leading cause of the global cancer incidence and mortality. It is important to obtain an accurate diagnosis of lymph-node metastasis before surgery to select the therapeutic strategy for non-small cell lung cancer (NSCLC) patients. Carbonic anhydrase 9 (CA9) is considered a marker of hypoxia and it has reported that CA9 is associated with tumor invasion and metastasis. In this study, the correlation between the CA9 expression for lymph-node metastases in NSCLC and [18F]FDG PET/CT results was investigated in order to clarify the efficacy of [18F]FDG PET/CT for detecting lymph-node metastases of NSCLC patients. Among the 564 patients who underwent surgical treatment for NSCLC between 2010 and 2016 at our hospital, a total of 338 patients who underwent preoperative [18F]FDG PET/CT were included in this study. CA9 expression was evaluated by immunochemistry. A lymph node with maximum standardized uptake value (SUVmax) ≥2.5 on [18F]FDG PET/CT was preoperatively defined as a metastatic lymph node. CA9 positivity was detected in 122 patients; the other 216 patients were CA9-negative. The CA9-positive NSCLC cases significantly associated with pleural invasion (p = 0.0063), pT-factor (p = 0.0080), pN-factor (p = 0.036) and pStage (p = 0.043). CA9-positive patients presented significantly poorer survival rate for OS than that of the CA9-negative patients (p = 0.0024). In the multivariable analysis, histological SCC and CA9 positivity were independent poor-prognosis factors for OS. For the total patient population, the sensitivity and specificity of [18F]FDG PET/CT for lymph-node metastases were 54% and 89%, respectively. In contrast, the sensitivity and specificity were particularly low in the CA9-positive SCC cases (36% and 69%, respectively). [18F]FDG PET/CT might not be useful for diagnosing lymph-node metastases of CA9-positive SCC cases of NSCLC.

8623 Atypical VHL Genetic Variant Causing Paraganglioma

Abstract Disclosure: G. Mangu: None. J.J. Faria Briceno: None. R. Yatavelli: None. Abstract: Pheochromocytomas and paragangliomas (PPGLs) are rare chromaffin cell tumors that originate from the adrenal medulla and extra-adrenal paraganglia respectively. Previous studies have shown that incidental PPGLs are seen in older patients with mild symptoms. They have lower levels of plasma catecholamines and lower incidence of malignancy than patients with nonincidental PPGLs. We report a case of an incidental paraganglioma in a young female with atypical pathogenic variant in the VHL gene which is known to cause familial erythrocytosis but NOT VHL syndrome or PPGL. Case Presentation: A 33-year-old African American female with no significant medical history presented to the emergency room with the chief complaint of right lower quadrant pain for 2 days, which started with her menstruation. The vitals were BP 128/67, pulse 67 and physical examination was unremarkable. CT showed a 4.0 x 3.0 cm heterogenous enhancing left adrenal mass and MRI with adrenal protocol revealed 3.4 x 3.1 cm mass consistent with pheochromocytoma. Labs revealed elevated plasma nor metanephrines and 24-hour urine normetanephrines were 1020 mcg. She was asymptomatic without hypertension, palpitations, or chest pain. She underwent laparoscopic left adrenalectomy after appropriate alpha blockade. The pathology report showed left periadrenal paraganglioma with immunohistochemistry staining significant for Carbonic anhydrase IX (CAIX) membranous expression which is mostly seen in paragangliomas associated with von Hippel-Lindau syndrome. Clinically, she did not have any stigmata for hereditary PPGL syndrome. Her genetic testing revealed a pathogenic heterozygous variant in the VHL gene, Exon 3, c.598C.T (pArg200Trp), which is a missense variant expected to disrupt VHL protein function. Although she has a germline mutation in VHL, it is not the garden variant which is associated with classic VHL syndrome. It has been reported to cause autosomal recessive erythrocytosis but not PPGL. Conclusion: The pathogenic heterozygous variant in VHL gene, Exon 3, c.598C.T (pArg200Trp) is known to cause autosomal recessive familial erythrocytosis type 2 in the Chuvash population, termed as Chuvash Polycythemia. Our patient did not have polycythemia but had iron deficiency anemia from menorrhagia. Several studies have reported that this variant does not cause VHL syndrome, however it has been reported in a single family with VHL syndrome but WITHOUT pheochromocytoma. To our knowledge, incidental adrenergic paraganglioma associated with this mutation has not been reported in the literature. Presentation: 6/3/2024

Application of carbonic anhydrase IX in sporadic hemangioblastoma of the central nervous system and hemangioblastoma associated with von Hippel-Lindau disease.

This research aims to examine the expression of carbonic anhydrase IX (CAIX) protein in hemangioblastoma of the central nervous system and its potential application in pathological diagnosis and differential diagnosis. Immunohistochemistry was used to identify the expression of CAIX and the α-inhibin protein. The sensitivity and specificity of CAIX and α-inhibin for identifying hemangioblastoma of the central nervous system were compared. In addition, 86 patients with meningiomas were gathered to detect CAIX protein expression. Hemangioblastoma and angiomatous, microcystic the two subtypes of meningiomas, were compared for CAIX and EMA protein expression. In hemangioblastoma, there were significant differences in the median positive percentage and staining intensity of CAIX and α-inhibin (p < 0.05). There was no discernible difference in the expression of the CAIX protein between sporadic hemangioblastoma of the central nervous system and those linked to von Hippel‒Lindau disease. In comparison to angiomatous and microcystic meningiomas, the positive rate of CAIX in hemangioblastomas was substantially greater (p < 0.001). The expression of EMA in microcystic meningioma (6/6) and angiomatous meningioma (17/17) was significantly different from hemangioblastoma (0/30) (p < 0.0001). Hemangioblastoma might be diagnosed with high specificity and sensitivity through CAIX immunohistochemistry. The combination of CAIX with EMA is useful for the diagnosis and differential diagnosis of hemangioblastoma.

A Smart CA IX-Targeting and pH-Responsive Nano-Mixed Micelles for Delivery of FB15 with Superior Anti-Breast Cancer Efficacy.

Breast cancer treatment has been a global puzzle, and targeted strategies based on the hypoxic tumor microenvironment (TME) have attracted extensive attention. As a signature transcription factor overexpressed in hypoxia tumor, hypoxia-inducible factor-1 (HIF-1) contribute to cancer progression. Compound 7-(3-(2-chloro-1H-benzo[d]1midazole-1-yl) propoxy)-2-(3,4,5-trime-thoxyphenyl)-4H-chromen-4-one, synthesized and named FB15 in our earlier research, a potential inhibitor of HIF-1α signaling pathway, has been proved a promising drug candidate for many kinds of cancer chemotherapy. However, the poor solubility and undesirable pharmacokinetics of FB15 leads to limited treatment efficacy of tumor, which ultimately restricts its potential clinical applications. Carbonic anhydrase IX (CAIX), a tumor cell transmembrane protein, was overexpressed in hypoxia tumor site. Acetazolamide (AZA), a highly selective ligand targeting CAIX, can be utilized to delivery FB15 to hypoxia tumor site. In this study, we prepared and characterized FB15 loaded nano-mixed micelles with the AZA conjugated poloxamer 188 (AZA-P188) and D-a-Tocopherol Polyethylene 1000 Glycol Succinate (TPGS), denoted as, AZA-P188/TPGS@FB15. Its delivery efficiency in vitro and in vivo was assessed by in vitro drug release, cytotoxicity assay, cellular uptake, and in vivo pharmacokinetics and fluorescence imaging. Finally, therapeutic effect of AZA-P188/TPGS@FB15 was investigated using a preclinical breast cancer subcutaneous graft model in vivo. In vitro studies revealed that AZA-P188/TPGS@FB15 could efficiently target breast cancer cells mediated by CAIX receptor, trigger FB15 release in response to acidic condition, and enhance cellular uptake and cytotoxicity against breast cancer cells. The pharmacokinetic studies showed that FB15-loaded AZA-functionalized micelles exhibited significantly increased AUC0-t over free FB15. In vivo imaging demonstrated that AZA-functionalized micelles significantly increased the drug distribution in the tumor site. In vivo experiments confirmed that AZA-P188/TPGS@FB15 exhibited superior inhibition of tumor growth in nude mice with good biosafety. AZA-P188/TPGS@FB15 hold promise as a potentially effective therapeutic way for breast cancer. Its targeted delivery system utilizing AZA as a carrier shows potential for improving the efficacy of FB15 in cancer therapy.

Cabozantinib enhances CAIX specific CAR-T cells against renal cancer by improving effector functions and augmenting tumor immune microenvironment

Despite demonstrating promising outcomes in treating hematologic malignancies, the efficacy of chimeric antigen receptor-modified T (CAR-T) cell therapy remains limited when applied to solid tumors due to tumor immune microenvironment (TIME). Strategies to augment CAR-T cell efficacy against solid tumors have been investigated by ameliorating TIME to a certain extent. In this study, Cabozantinib was utilized in combination with CAR-T cells targeting carbonic anhydrase IX (CAIX) for the treatment of renal cancer. Our findings indicate that combination therapy with CAIX-CAR-T and Cabozantinib demonstrated synergistic efficacy against an orthotopic xenograft tumor model and a subcutaneous tumor model of renal cell carcinoma in mice. Mechanistically, it was observed that CAR-T cells combined with Cabozantinib led to an increase in the infiltration of tumor-infiltrating T cells, while reducing tumor-associated macrophages and M2 polarization. Additionally, Cabozantinib blocked the programmed cell death-1 (PD-1)/programmed death-ligand 1 (PD-L1) axis by decreasing the expression of PD-L1 in tumor cells and PD-1 in T cells. Furthermore, Cabozantinib promoted CAR-T cell effector function and reduced T cell exhaustion. This combination therapy represents a novel approach to enhancing CAR-T cell efficacy against solid tumors and holds significant promise for advancing CAR-T cell therapy in clinical settings.

Combination treatment with histone deacetylase and carbonic anhydrase 9 inhibitors shows therapeutic potential in experimental diffuse intrinsic pontine glioma.

Diffuse intrinsic pontine glioma (DIPG) remains a significant therapeutic challenge due to the lack of effective and safe treatment options. This study explores the potential of combining histone deacetylase (HDAC) and carbonic anhydrase 9 (CA9) inhibitors in treating DIPG. Analysis of RNA sequencing data and tumor tissue from patient samples for the expression of the carbonic anhydrase family and hypoxia signaling pathway activity revealed clinical relevance for targeting CA9 in DIPG. A synergy screen was conducted using CA9 inhibitor SLC-0111 and HDAC inhibitors panobinostat, vorinostat, entinostat, and pyroxamide. The combination of SLC-0111 and pyroxamide demonstrated the highest synergy and was selected for further analysis. Combining SLC-0111 and pyroxamide effectively inhibited DIPG cell proliferation, reduced cell migration and invasion potential, and enhanced histone acetylation, leading to decreased cell population in S Phase. Additionally, the combination therapy induced a greater reduction in intracellular pH than either agent alone. Data from this study suggest that the combination of SLC-0111 and pyroxamide holds promise for treating experimental DIPG, and further investigation of this combination therapy in preclinical models is warranted to evaluate its potential as a viable treatment for DIPG.

Design and Synthesis of 3-(Phenylsulfonamido)benzamide Derivatives as Potent Carbonic Anhydrase IX Inhibitors: Biological Evaluations and Molecular Modeling Studies

Introduction: Carbonic anhydrase IX (CAIX) is known to be overexpressed in various tumors and plays a significant role in tumor development and progression. Methods: A series of 3-(benzylsulfonamido)benzamides derivatives was synthesized and tested for their CAIX inhibitory activities. The two most active compounds were subjected to cytotoxicity testing against a panel of 60 cancer cell lines. Results: Many of the synthesized compounds successfully inhibited CAIX activities, exhibiting IC50 values in the low nanomolar range. The most potent CAIX inhibitor was compound 14, with an IC50 of 140 nM. Structure-activity relationship analysis of the synthesized compounds supported with molecular docking revealed strong coordination of sulfonamide moiety with the catalytic Zn2+ metal, hydrophobic interactions of the benzylsulfonamido ring with a hydrophobic pocket, and π- stacking interactions of the aryl ring with an aromatic surface. The two most active analogues (10 and 14) were further tested for their antiproliferative activities in the NCI-60 human tumor cell lines. Notably, compound 14 demonstrated potent growth inhibitory effects against several cancer cell lines. Conclusion: The synthesized analogues represent a novel scaffold for the treatment of different types of cancer by targeting CAIX.

Renal Cell Carcinoma with Sarcomatoid and Rhabdoid Dedifferentiation: Clinico Pathological Significance- Review

Introduction Sarcomatoid and/or rhabdoid dedifferentiation are rare histopathological findings which may be heterogeneous in renal cell carcinoma. Sarcomatoid renal cell carcinoma shows marked cytologic atypia and containing enlarged pleomorphic and malignant spindle cells reminiscent of sarcoma. It is highly aggressive with a high metastatic potential and extremely poor prognosis. Case report A 78-year-old male presented with complaints hematuria, pain abdomen, burring maturation of 2 months duration. The patient had a history of hypertension and diabetes mellitus. Computed tomography revealed a well-defined lobulated, exophytic ball-type, isodense lesion, measuring (~ 7.8 x 7.5 x 11.0 cm) arising from mid and lower poles of right kidney involving renal sinus. Features were suggestive of renal cell carcinoma. The patient underwent a right radical nephrectomy. On histopathological findings reported as clear cell RCC, sarcomatoid and rhabdoid dedifferentiation, Fuhrman grade IV. There was no evidence of any metastasis. The immunochemistry was positive for Paired box 8 (PAX8), Carbonic anhydrase 9 (CA9). The BAP1: BRCA1 Associated Protein-1 was retained. Conclusion-Herewith present an uncommon case of highly aggressive tumor clear cell RCC sarcomatoid and rhabdoid differentiation for its clinical, radioimaging, histopathological and immunohistochemitry significance with review.

Acetazolamide suppresses the progression of hepatocellular carcinoma induced by diethylnitrosamine in Wistar albino rats.

Hepatocellular carcinoma (HCC) continues to be the most prevalent type of liver cancer worldwide. Diethylnitrosamine (DEN)-induced HCC is an extensively used hepatic cancer model in experimental animals. Acetazolamide (AZA) is a carbonic anhydrase enzyme inhibitor. This study aimed to assess the therapeutic mechanism of AZA against DEN-induced HCC. Thirty male Wistar albino rats were divided equally into three groups. Group I (C): control group, Group II (HCC): DEN-induced HCC, and Group III (HCC/AZA): AZA-treated HCC. Verification of the HCC induced by DEN was confirmed by elevated liver enzymes' activities, and increased α-fetoprotein (AFP) levels, as well as distinct liver architecture changes. On the other hand, the AZA-treated HCC group experienced decreases in the activities of serum liver enzymes and AFP levels, as well as, regulated liver architecture. Additionally, it downregulated p-p38 MAPK/p-JNK1/JNK2/p-C-Jun/p-NF-κB p65 protein expressions. Moreover, it ameliorated autophagy by controlling the expression of the p-AMPK/p-mTOR1/LC3 I/II proteins. Furthermore, it downregulated the relative gene expressions of carbonic anhydrase-IX (CAIX) and hexokinase-II (HKII). Histopathological examination of AZA-treated HCC liver tissues supported these findings. Conclusion: AZA provides a new dimension in ameliorating experimentally induced HCC through regulation of hepatic biomarkers, antioxidant status, inflammatory markers, and autophagy, mediated by amelioration of CAIX and HKII gene expressions.

Clinical impact of carbonic anhydrase 9 expression on neoadjuvant chemoradiotherapy in pancreatic ductal adenocarcinoma

BackgroundPDAC cells upregulate carbonic anhydrase 9 (CA9) expression in order to survive in hypoxic tumor environments, which plays a key role in tumor progression. However, the relationship between CA9 expression and preoperative treatment has not been clarified. We evaluated the clinical impact of CA9 expression on the efficacy of neoadjuvant chemoradiotherapy (NACRT) in pancreatic ductal adenocarcinoma (PDAC). MethodsWe investigated CA9 expression in 273 surgical specimens and 20 serum samples obtained from patients with PDAC and evaluated their clinical outcomes. We analyzed the function of CA9 using human pancreatic cancer cell lines. ResultsCA9 was positively expressed in 36.2 % of patients who underwent NACRT, which was significantly lower than those who underwent upfront surgery (US) (58.9 %, p < 0.001). Interestingly, patients who were CA9-positive in the US group had a significantly poorer prognosis than that of those in the NACRT group (median survival time [MST], 21.5 months vs. 49.2 months, p < 0.001), while there was no significant difference between patients who were CA9-negative in the US and NACRT groups (MST, 45.8 months vs. 46.3 months, p = 0.357). Moreover, serum CA9 levels tended to correlate positively with CA9 expression in cancer tissues. In-vitro experiments demonstrated that CA9 expression was reduced after treatments with radiation and chemoradiation therapy (RT/CRT), and that CA9 knockdown suppressed the impact of RT/CRT on cancer cell proliferation. ConclusionsCA9 may act as a target molecule for RT/CRT, highlighting its clinical importance as a valuable biomarker for more stringent indications for NACRT.

Diagnostic efficacy of [68Ga]Ga-NY104 PET/CT to identify clear cell renal cell carcinoma.

Most clear cell renal cell carcinoma (ccRCC) overexpresses carbonic anhydrase IX (CAIX). [68Ga]Ga-NY104 is a small-molecule PET agent selectively targeting CAIX. This study aims to assess the efficacy of [68Ga]Ga-NY104 PET/CT to identify ccRCC. Participants were prospectively recruited in the study (ClinicalTrials.gov: NCT05902377). They were further divided into two groups: group 1, patients with primary renal mass who were scheduled for surgery, group 2, patients with suspected/confirmed metastatic ccRCC. All patients underwent [68Ga]Ga-NY104 PET/CT. A total of 47 patients (mean age, 58.8years ± 13.5, 34 men) were recruited, including 20 patients in group 1 and 27 patients in group 2. The patient-level sensitivity, specificity, and accuracy of [68Ga]Ga-NY104 PET scan was 62%, 33%, 58% for group 1 and 95%, 100%, 96% for group 2. [68Ga]Ga-NY104 PET identified additional 26 disease regions in 67% (14/21) of patients that were previously unknown. The tumor uptake was correlated with immunohistochemical staining results. [68Ga]Ga-NY104 PET/CT has a high diagnostic efficacy for patients with metastatic ccRCC, while it might be of limited value in the diagnosis of primary ccRCC.

BIOM-01. CARBONIC ANHYDRASE IX INTERPLAY WITH LOCAL AND SYSTEMIC IMMUNE RESPONSE IN PEDIATRIC BRAIN TUMORS

Abstract BACKGROUND Brain tumors (BT) remain the leading cause of death among childhood cancers. There is an urgent need to identify novel targets in these patients. BT progression depends on the adaptive responses to hypoxia. Carbonic anhydrase IX (CAIX) helps cancer cells survive in a hypoxic environment and can be potentially as a therapeutic target. The role of CAIX in the interplay between the tumor and immune cells requires in-depth investigation to design effective therapies. METHODS Fresh BT, blood, and intraoperative cerebrospinal fluid (iCSF) samples were collected prospectively from pediatric patients, who underwent brain tumor surgery at Vilnius University Hospital Santaros Klinikos from March 2022 to December 2023. All tumor types were included. Immunohistochemistry (IHC) and flow cytometry (FC) were performed to analyze the expression of CAIX and selected immunological markers in the fresh tumor, iCSF and peripheral blood mononuclear cells (PBMCs). Soluble CAIX content in serum and iCSF was assessed by ELISA. In addition, a retrospective analysis of previously diagnosed pediatric glioma specimens was performed by IHC. RESULTS Twelve patients with heterogeneous BT types have been enrolled prospectively and 17 patients with glioma were reviewed retrospectively. Glioma accounted for 72% (21/29) of all samples. IHC showed that 57% of gliomas were positive for CAIX as well as a moderate correlation between the CAIX score and the expression of CD44, CD206, and CCR2 markers. PD-1/PD-L1 expression was negligible. In the prospective cohort, 83% (10/12) of BT tissue was positive for CAIX by IHC and FC. Soluble CAIX was detectable in 40% of iCSF samples, but not in serum. We found a correlation trend of CAIX expression in the fresh tumor cells and iCSF with increased CCR2 expression on CD45+ PBMCs. CONCLUSIONS This interim analysis showed a correlation between CAIX tumor expression and immune biomarkers, prompting further investigation by enrolling more patients.

Epigenetic Regulation of Carbonic Anhydrase 9 Expression by Nitric Oxide in Human Small Airway Epithelial Cells.

DNA methylation is a crucial epigenetic modification that regulates gene expression and determines cell fate; however, the triggers that alter DNA methylation levels remain unclear. Recently, we showed that S-nitrosylation of DNA methyltransferase (DNMT) induces DNA hypomethylation and alters gene expression. Furthermore, we identified DBIC, a specific inhibitor of S-nitrosylation of DNMT3B, to suppress nitric oxide (NO)-induced gene alterations. However, it remains unclear how NO-induced DNA hypomethylation regulates gene expression and whether this mechanism is maintained in normal cells and triggers disease-related changes. To address these issues, we focused on carbonic anhydrase 9 (CA9), which is upregulated under nitrosative stress in cancer cells. We pharmacologically evaluated its regulatory mechanisms using human small airway epithelial cells (SAECs) and DBIC. We demonstrated that nitrosative stress promotes the recruitment of hypoxia-inducible factor 1 alpha to the CA9 promoter region and epigenetically induces CA9 expression in SAECs. Our results suggest that nitrosative stress is a key epigenetic regulator that may cause diseases by altering normal cell function.

A CAIX Dual-Targeting Small-Molecule Probe for Noninvasive Imaging of ccRCC.

Carbonic anhydrase IX (CAIX), a zinc metal transmembrane protein, is highly expressed in 95% of clear cell renal cell carcinomas (ccRCCs). A positron emission tomography (PET) probe designed to target CAIX in nuclear medicine imaging technology can achieve precise positioning, is noninvasive, and can be used to monitor CAIX expression in lesions in real time. In this study, we constructed a novel acetazolamide dual-targeted small-molecule probe [68Ga]Ga-LF-4, which targets CAIX by binding to a specific amino acid sequence. After attenuation correction, the radiolabeling yield reached 66.95 ± 0.57% (n = 5) after 15 min of reaction and the radiochemical purity reached 99% (n = 5). [68Ga]Ga-LF-4 has good in vitro and in vivo stability, and in vivo safety and high affinity for CAIX, with a Kd value of 6.62 nM. Moreover, [68Ga]Ga-LF-4 could be quickly cleared from the blood in vivo. The biodistribution study revealed that the [68Ga]Ga-LF-4 signal was concentrated in the heart, lung, and kidney after administration, which was the same as that observed in the micro-PET/CT study. In a ccRCC patient-derived xenograft (PDX) model, the signal significantly accumulated in the tumor after administration, where it was retained for up to 4 h. After competitive blockade with LF-4, uptake at the tumor site was significantly reduced. The SUVmax of the probe [68Ga]Ga-LF-4 at the ccRCC tumor site was three times greater than that in the PC3 group with low CAIX expression at 30 min (ccRCC vs PC3:1.86 ± 0.03 vs 0.62 ± 0.01, t = 48.2, P < 0.0001). These results indicate that [68Ga]Ga-LF-4 is a novel small-molecule probe that targets CAIX and can be used to image localized and metastatic ccRCC lesions.

Format-tuning of in vivo-launched bispecific T cell engager enhances efficacy against renal cell carcinoma

BackgroundAdvanced clear cell renal cell carcinoma (ccRCC) is a prevalent kidney cancer for which long-term survival rates are abysmal, though immunotherapies are showing potential. Not yet clinically vetted are bispecific...

IL-22 regulates MASTL expression in intestinal epithelial cells.

Microtubule-associated serine-threonine kinase-like (MASTL) has recently been identified as an oncogenic kinase given its overexpression in numerous cancers. Our group has shown that MASTL expression is upregulated in mouse models of sporadic colorectal cancer and colitis-associated cancer (CAC). CAC is one of the most severe complications of chronic inflammatory bowel disease (IBD), but a limited understanding of the mechanisms governing the switch from normal healing to neoplasia in IBD underscores the need for increased research in this area. However, MASTL levels in patients with IBD and its molecular regulation in IBD and CAC have not been studied. This study reveals that MASTL is upregulated by the cytokine interleukin (IL)-22, which promotes proliferation and has important functions in colitis recovery; however, IL-22 can also promote tumorigenesis when chronically elevated. Upon reviewing the publicly available data, we found significantly elevated MASTL and IL-22 levels in the biopsies from patients with late-stage ulcerative colitis compared with controls, and that MASTL upregulation was associated with high IL-22 expression. Our subsequent in vitro studies found that IL-22 increases MASTL expression in intestinal epithelial cell lines, which facilitates IL-22-mediated cell proliferation and downstream survival signaling. Inhibition of AKT activation abrogated IL-22-induced MASTL upregulation. We further found an increased association of carbonic anhydrase IX (CAIX) with MASTL in IL-22-treated cells, which stabilized MASTL expression. Inhibition of CAIX prevented IL-22-induced MASTL expression and cell survival. Overall, we show that IL-22/AKT signaling increases MASTL expression to promote cell survival and proliferation. Furthermore, CAIX associates with and stabilizes MASTL in response to IL-22 stimulation.NEW & NOTEWORTHY MASTL is upregulated in colorectal cancer; however, its role in colitis and colitis-associated cancer is poorly understood. This study is the first to draw a link between MASTL and IL-22, a proinflammatory/intestinal epithelial recovery-promoting cytokine that is also implicated in colon tumorigenesis. We propose that IL-22 increases MASTL protein stability by promoting its association with CAIX potentially via AKT signaling to promote cell survival and proliferation.

OTUB2 silencing promotes ovarian cancer via mitochondrial metabolic reprogramming and can be synthetically targeted by CA9 inhibition

Ovarian cancer is an aggressive gynecological tumor characterized by a high relapse rate and chemoresistance. Ovarian cancer exhibits the cancer hallmark of elevated glycolysis, yet effective strategies targeting cancer cell metabolic reprogramming to overcome therapeutic resistance in ovarian cancer remain elusive. Here, we revealed that epigenetic silencing of Otubain 2 (OTUB2) is a driving force for mitochondrial metabolic reprogramming in ovarian cancer, which promotes tumorigenesis and chemoresistance. Mechanistically, OTUB2 silencing destabilizes sorting nexin 29 pseudogene 2 (SNX29P2), which subsequently prevents hypoxia-inducible factor-1 alpha (HIF-1α) from von Hippel-Lindau tumor suppressor-mediated degradation. Elevated HIF-1α activates the transcription of carbonic anhydrase 9 (CA9) and drives ovarian cancer progression and chemoresistance by promoting glycolysis. Importantly, pharmacological inhibition of CA9 substantially suppressed tumor growth and synergized with carboplatin in the treatment of OTUB2-silenced ovarian cancer. Thus, our study highlights the pivotal role of OTUB2/SNX29P2 in suppressing ovarian cancer development and proposes that targeting CA9-mediated glycolysis is an encouraging strategy for the treatment of ovarian cancer.

Abstract PS13-04: Frequent Intra-Tumoral Hypoxia in Pregnancy-Associated Breast Cancer

Abstract Rationale: Breast cancer is the most common malignancy in pregnant women, occurring in approximately 1:3000 pregnancies. Breast cancer diagnosed during pregnancy or after childbirth is also known as Pregnancy-Associated Breast Cancer (PABC). PABC is known for exhibiting several unfavorable prognostic tumor characteristics, such as an advanced tumor stage at diagnosis, high histologic grade and frequent hormone receptor negativity. Most probably, several interplaying mechanisms may promote the tumor progression and adverse clinical outcome of PABC. One of these mechanisms may be the presence of hypoxia, a relative state of low intra-tumoral oxygen levels which is a known marker of adverse outcome in breast cancer. However, the occurrence and prognostic consequences of the presence of intra-tumoral hypoxia in PABC have not been studied yet. Methods: We constructed a cohort with histopathological, clinical, and outcome data of patients diagnosed with breast cancer during pregnancy (PrBC) or within one year after childbirth (PPBC) in the Netherlands between 1988 and 2022. Next, tissue blocks of all patients were collected from the participating Dutch pathology laboratories. Using H&amp;E stained slides of the tumor tissue blocks, we selected suitable donor sites for a tissue micro array (TMA). Slides from these TMAs were stained for three important hypoxia-associated proteins: glucose transporter-1 (Glut-1), carbonic anhydrase IX (CAIX) and hypoxia-inducible factor-1α (HIF-1α). Expression was scored by an expert breast pathologist blinded by clinicopathologic data. Results: For a total of 195 PrBC and PPBC patients, we were able to assess the expression of Glut-1, CAIX and HIF-1α on tumor cells. Patients had a median age of 33 years at diagnosis, whilst a large majority had a Bloom &amp; Richardson grade III tumor (76%) with frequent hormone receptor negativity (50%). Expression of hypoxia-associated proteins was frequent, with 61% of the tumors expressing Glut-1, 30% expressing CAIX and 56% expressing HIF-1α. In total, 153 (78%) of the tumors expressed at least one of the hypoxia-associated proteins. We observed a significantly worse 5-year overall survival for patients with intra-tumoral hypoxia in comparison to patients without intra-tumoral hypoxia (70% vs. 90%, p=0.046). Conclusions: We show that the presence of intra-tumoral hypoxia in PABC is common, with 78% of tumors expressing at least one of the studied hypoxia-associated proteins. Importantly, patients with tumors overexpressing hypoxia-markers have a significantly worse survival. This shows that intra-tumoral hypoxia may be an important underlying carcinogenic mechanism in PABC, and might be a promising novel therapeutic target in this patient group. Citation Format: Carsten Bakhuis, Carmen Van Dooijeweert, Britt Suelmann, Pieter Westenend, Sabine Linn, Elsken Van der Wall, Paul Van Diest. Frequent Intra-Tumoral Hypoxia in Pregnancy-Associated Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS13-04.

Aerobic vaginitis is associated with carbonic anhydrase IX in cervical intraepithelial neoplasia

The aim of this study was to analyze the association between vaginal microbiota, carbonic anhydrase IX (CAIX) and histological findings of cervical intraepithelial neoplasia (CIN). The study included 132 females, among them 66 were diagnosed with high-grade intraepithelial lesion (CIN2, CIN3, and cancer), 14 with low-grade disease, and 52 assigned to the control group. An interview focused on the behavior risk factors, together with vaginal fluid pH measurement, wet mount microscopy, detection of Chlamydia trachomatis, and Trichomonas vaginalis were performed. After colposcopy, high-grade abnormalities were detected via direct biopsies and treated with conization procedure. Conuses were immuno-stained with CAIX antibody. The histological findings were CIN1 (n = 14), and CIN2+ (included CIN2 (n = 10), CIN3 (n = 49), and cancer (n = 7; squamous cell carcinomas)). Prevalence of bacterial vaginosis (BV) was similar between the groups. Moderate or severe aerobic vaginitis (msAV) was diagnosed more often among CIN2+ (53.0%) than CIN1 (21.4%). Moderate or strong immunostaining of CAIX (msCAIX) was not detected among CIN1 cases. Thus, msAV was prevalent in CAIX non-stained group (p = 0.049) among CIN2 patients. Co-location of msAV and msCAIX was found in CIN3. Regression model revealed that msAV associated with high-grade cervical intraepithelial neoplasia independently from smoking and the number of partners.