Carbonic anhydrase IX and acid transport in cancer

Carbonic anhydrase-9-targeted near-infrared photoimmunotherapy as a theranostic modality for clear cell renal cell carcinoma

Carbonic anhydrase-9 (CA9) is highly expressed in clear cell renal cell carcinoma (ccRCC) cells despite no expression in normal kidney tissues. Thus, CA9 has been proposed as a theranostic target for radioligand therapy (RLT). However, ccRCC tends to be radioresistant and may not effectively respond to RLT. Alternatively, CA9 can be targeted for near-infrared photoimmunotherapy (NIR-PIT) of ccRCC. Here, we sought to test NIR-PIT using CA9 in a preclinical model of ccRCC to determine its potential as a therapeutic strategy. Tissue microarray analysis showed that membrane CA9 was expressed in the majority of ccRCC cases. In vitro, CA9-targeted NIR-PIT induced cell membrane damage and cell killing in all CA9-expressing ccRCC cell lines specifically, UOK154, UOK220, and UOK122. In vivo, CA9-targeted NIR-PIT significantly inhibited tumor growth and prolonged survival in UOK154 and UOK220 subcutaneous xenograft models. Notably, 70%-80% of mice achieved complete remission after a single treatment of NIR-PIT. Additionally, remaining tumors after the first NIR-PIT persistently expressed CA9, suggesting that remaining tumors can be treated with repeated NIR-PIT. Furthermore, CA9-targeted NIR-PIT induced significant cytoplasmic damages on ccRCC cells in UOK154 orthotopic xenograft models. In conclusion, CA9-targeted NIR-PIT, which allow for safe and repeated application on the same lesion, is a promising treatment for ccRCC, especially in the management of multiple primary ccRCC (e.g., von Hippel-Lindau syndrome) and oligometastatic ccRCC.

Two-photon photosensitizer for specific targeting and induction of tumor pyroptosis to elicit systemic immunity-boosting anti-tumor therapy

Photodynamic therapy (PDT) has garnered increasing attention in cancer treatment due to its precise spatiotemporal selectivity and non-invasive nature. However, several challenges, including the inability of photosensitizers to discriminate between tumor and healthy tissues, as well as the limited tissue penetration depth of light sources, impede its broader application. To surmount these impediments, our research introduces a two-photon photosensitizer (TPSS) that specifically targets tumor overexpressing carbonic anhydrase IX (CA IX), thereby exhibiting exceptional specificity for tumor cells. Under two-photon laser stimulation, TPSS generates a large amount of reactive oxygen species (ROS), inducing cell pyroptosis and subsequently triggering a strong anti-tumor immune response. Additionally, proteomics analysis provides compelling evidence to elucidate the anti-tumor mechanism of TPSS in vivo. Through comprehensive immune assessments, TPSS under two-photon laser irradiation effectively activates both the innate and adaptive immune systems, efficiently suppressing the proliferation of distant metastatic tumors, underscoring its considerable therapeutic potential. Collectively, this study provides a viable strategy to overcome the limitations of PDT, highlighting the prospects of two-photon excitation photosensitizers.

Antibody-drug conjugates and radioconjugates targeting carbonic anhydrase IX and XII in hypoxic tumors: Bench to clinical applications

Treating hypoxic tumors is challenging due to their aggressive nature, resistance to standard treatments, often leading to poor outcomes. Hypoxic tumors create a unique environment that reduces the effectiveness of traditional treatments such as chemotherapy and radiotherapy. Human carbonic anhydrases (hCA IX and hCA XII) are involved in tumors survival and metabolism by regulating pH homeostasis, ferroptosis, metastatization, and other processes. Developing drugs that specifically target these enzymes has been demonstrated to disrupt the tumor survival mechanisms, leading to significant antitumor effects. This review discusses recent developments on antibody-drug conjugates (ADCs) and radioconjugates targeting hCA IX and hCA XII in hypoxic tumors. New approaches based on small molecule inhibitors and monoclonal antibodies such as girentuximab provided encouraging results in preclinical research and clinical trials. These advances highlight the potential of hCA-targeted therapies to improve cancer treatment for hypoxic tumors.

Self-healable and pH-responsive spermidine/ferrous ion complexed hydrogel Co-loaded with CA inhibitor and glucose oxidase for combined cancer immunotherapy through triple ferroptosis mechanism

Tumor microenvironment governs various therapeutic tolerability of cancer such as ferroptosis and immunotherapy through rewiring tumor metabolic reprogramming like Warburg metabolism. Highly expressed carbonic anhydrases (CA) in tumor that maintaining the delicate metabolic homeostasis is thus the most potential target to be modulated to resolve the therapeutic tolerability. Hence, in this article, a self-healable and pH-responsive spermidine/ferrous ion hydrogel loaded with CA inhibitor (acetazolamide, ACZ) and glucose oxidase (ACZ/GOx@SPM-HA Gel) was fabricated through the Schiff-base reaction between spermidine-dextran and oxidized hyaluronic acid, along with ferrous coordination. Investigation on cancer cell lines (MOC-1) demonstrated ACZ/GOx@SPM-HA Gel may induce cellular oxidative stress and mitochondrial dysfunction through disrupting the cellular homeostasis. Moreover, with the facilitation of autophagy induced by spermidine, ACZ/GOx@SPM-HA Gel may trigger a positive feedback loop to maximally amplify cellular ferroptosis and promote DAMPs release. The anti-tumor evaluation on xenograft mice models furtherly proved the local injection of such hydrogel formulation could efficiently inhibit the tumor growth and distinctively promote the immunogenicity of tumor bed to provide a more favorable environment for immunotherapy. Overall, ACZ/GOx@SPM-HA Gel, with such feasible physiochemical properties and great biocompatibility, holds great potential in treating solid tumors with acidosis-mediated immunotherapy tolerance.

X-ray crystallographic and kinetic studies of biguanide containing aryl sulfonamides as carbonic anhydrase inhibitors

Here, we report a small series of dual-targeting compounds that combine the prototypical carbonic anhydrase (CA) zinc-binding sulfonamide moiety with the biguanide group of metformin, an emerging anticancer drug. The compounds reported similar in vitro inhibition profiles on a panel of physiologically relevant human (h)CAs, with marked selectivity for the cancer related IX and XII isoforms. The binding modes of representative inhibitors 5b and 5c within the active site of the hCA isoforms II and XII-mimic were assessed by X-ray crystallography, thus allowing us to clarify molecular features that may be useful for the design of more specific and potent inhibitors. For instance, we identified a mutation in the hCA XII-mimic which was found responsible for the selectivity of the ligands toward the tumor associated isoform. Interestingly, in the hCA II/5c complex, a second inhibitor molecule was bound to the catalytic cleft, probably affecting the inhibition properties of the canonical zinc-bound inhibitor.

Bifunctional compounds for targeted degradation of carbonic anhydrase IX through integrin-facilitated lysosome degradation

As an important therapeutic target, carbonic anhydrase IX (CAIX) is crucial in pH regulation of hypoxic solid tumors, thus keeping the survival of them in acidic microenvironment, and promoting their proliferation, invasion and metastasis. To degrade endogenous CAIX, three bifunctional compounds were designed according to the integrin-facilitated lysosomal degradation (IFLD) strategy. These compounds are composed of a CAIX binding ligand, an integrin-recognizing ligand, connected via a linker, which could induce CAIX degradation in an integrin- and lysosome-dependent manner. Among them, Sul-L1-RGD showed the highest degradation efficacy, and could inhibit the proliferation of tumor cells under hypoxic conditions, thus it has great potential to be applied in cancer drug discovery.

Reprogramming of Glucose Metabolism by Nanocarriers to Improve Cancer Immunotherapy: Recent Advances and Applications

Although immunotherapy has made significant progress in cancer treatment, its limited responsiveness has greatly hindered widespread clinical application. The Warburg effect in tumor cells creates a tumor microenvironment (TME) characterized by hypoxia, low glucose levels, and high lactate levels, which severely inhibits the antitumor immune response. Consequently, targeting glucose metabolism to reprogram the TME is considered an effective strategy for reversing immunosuppression and immune evasion. Numerous studies have been conducted on enhancing cancer immunotherapy efficacy through the delivery of glucose metabolism modulators via nanocarriers. This review provides a comprehensive overview of the glucose metabolic characteristics of tumors and their impacts on the immune system, as well as nanodelivery strategies targeting glucose metabolism to enhance immunotherapy. These strategies include inhibiting key glycolytic enzymes, blocking glucose and lactate transporters, and utilizing glucose oxidase and lactate oxidase. Furthermore, this article reviews recent advancements in synergistic antitumor therapy involving glucose metabolism-targeted therapy combined with other treatments, such as chemotherapy, radiotherapy (RT), phototherapy, and immunotherapy. Finally, we discuss the limitations and future prospects of nanotechnology targeting glucose metabolism therapy, hoping to provide new directions and ideas to improve cancer immunotherapy.

The role of protein lactylation: A kaleidoscopic post-translational modification in cancer

The recently discovered lysine lactylation represents a critical post-translational modification with widespread implications in epigenetics and cancer biology. Initially identified on histones, lysine lactylation has been also described on non-histone proteins, playing a pivotal role in transcriptional activation, protein function, and cellular processes. Two major sources of the lactyl moiety have been currently distinguished: L-lactyl-CoA (precursor of the L-lactyl moiety) and S-D-lactylglutathione (precursor of the D-lactyl moiety), which enable enzymatic and non-enzymatic mechanisms of lysine lactylation, respectively. Although the specific writers, erasers, and readers of this modification are still unclear, acetyltransferases and deacetylases have been proposed as crucial mediators of lysine lactylation. Remarkably, lactylation exerts significant influence on critical cancer-related pathways, thereby shaping cellular behavior during malignant transformation and the metastatic cascade. Hence, as recent insights into lysine lactylation underscore its growing potential in tumor biology, targeting this modification is emerging as a significant opportunity for cancer treatment.

UBC4: A Repurposed Drug Regimen for Adjunctive Use During Bladder Cancer Treatment

After it has metastasized, bladder cancer, the malignant transformation of the bladder urothelium, continues to be a common cause of death after maximal use of all currently available standard treatments. To address this problem in 2025, the drug repurposing movement within oncology aims to identify medicines in common general medical care use that have data indicating that they can interfere or inhibit a growth driving element that has been identified in bladder cancer. This paper now outlines extensive preclinical data showing that four drugs from general medical practice meet these criteria-the melatonergic drug ramelteon, the antidepressant fluoxetine, the antibiotic dapsone, and the analgesic drug celecoxib. This is the UBC4 regimen, meant as a possible adjunct added to standard treatments of metastatic bladder cancer. Three factors justify a clinical pilot trial of UBC4: (1) the UBC4 drugs are usually well tolerated and carry a low risk of harm, (2) the commonly fatal outcome of bladder cancer once it has widely metastasized, plus (3) the strong preclinical database showing UBC growth inhibition by each of the individual UBC4 drugs as outlined in this paper.

Supramolecular Nanozymes Based on Self-Assembly of Biomolecule for Cancer Therapy

Natural enzyme systems possess extraordinary functions and characteristics, making them highly appealing for use in eco-friendly technologies and innovative cancer treatments. However, their inherent instability and structural complexity often limit their practical applications, leading to the exploration of biomolecular nanozyme alternatives. Supramolecular nanozymes, constructed using self-assembly techniques and various non-covalent interactions, have emerged as a promising solution. Amino acids, peptides, and protein motifs offer flexible building blocks for constructing these nanozymes. Importantly, the well-defined structural regulation mechanisms of biomolecular nanozymes, along with their unique properties as fundamental biological modules in living systems-such as selectivity, permeability, retention, and biocompatibility-present new opportunities for cancer therapy. This review highlights recent advances in supramolecular self-assembled nanozymes, including peroxidases, oxidases, catalases, superoxide dismutases, and other nanozyme systems, as building blocks for tumor therapy. Additionally, it discusses precise functional modulation through supramolecular non-covalent interactions and their therapeutic applications in targeting the tumor microenvironment. These studies provide valuable insights that may inspire the design of novel supramolecular nanozymes with enhanced catalytic selectivity, biocompatibility, and tumor-killing efficacy.

Engineered Reactive Oxygen Species (ROS)-Responsive Artificial H+/Cl- Ion Channels for Targeted Cancer Treatment

Reactive oxygen species (ROS)-responsive ion channels regulate the ion flow across the membranes in response to alterations in the cellular redox state, playing a crucial role in cellular adaptation to oxidative stress. Despite their significance, replicating ROS-responsive functionality in artificial ion channels remains elusive. In this study, we introduce a novel class of artificial H+/Cl- ion channels activatable by elevated ROS levels in cancer cells. ROS-induced decaging of the phenylboronate group triggers the rapid release of the channel-forming units, leading to self-assembly of the H-bonded cascades facilitating the synergistic transport of H+ and Cl- ions, with H+/Cl- ion transport selectivity of 7.7. Upon activation, ROS-C-Cl exhibits significant apoptotic activity against human breast cancer cells, achieving an IC50 of 2.8 μM, comparable to that of paclitaxel. Exploiting the intrinsic oxidative microenvironment of cancer cells, along with the enhanced oxidative stress arising from H+/Cl- co-transport, ROS-C-Cl demonstrates exceptional selectivity in targeting cancer cells with a selectivity index of 10.2 over normal breast cells, outperforming that of paclitaxel by 19.4 folds.

A series of benzensulfonamide derivatives as new potent carbonic anhydrase IX and XII inhibitors

AIM

Human carbonic anhydrases (hCAs) are involved in many physiological processes including respiration, pH control, ion transport, bone resorption, and gastric fluid secretion. Recently, CA IX and CA XII have been studied for their role in cancer diseases, motivating the design of inhibitors of these isoforms.

MATERIAL AND METHOD

Here, we used the tail approach to design a new series of monoaryl (1a-i) and bicyclic (1j-n) benzensulfonamide derivatives CA IX and CA XII inhibitors. All synthesized compounds were investigated toward a panel of hCAs, and most of them exhibited potent CA inhibitory activity for CA II, CA IX and CA XII with Ki values. In silico studies were performed to investigate the binding mode between inhibitors and CA.

RESULTS AND CONCLUSION

The best compound was 1i that showed a low nanomolar range of Ki value as CA inhibitor (Ki = 9.4, 5.6 and 6.3 nM hCA II, IX and XII, respectively).

Acidity and hypoxia of tumor microenvironment, a positive interplay in extracellular vesicle release by tumor cells

The complex and continuously evolving features of the tumor microenvironment, varying between tumor histotypes, are characterized by the presence of host cells and tumor cells embedded in a milieu shaped by hypoxia and low pH, resulting from the frequent imbalance between vascularity and tumor cell proliferation. These microenvironmental metabolic stressors play a crucial role in remodeling host cells and tumor cells, contributing to the stimulation of cancer cell heterogeneity, clonal evolution, and multidrug resistance, ultimately leading to progression and metastasis. The extracellular vesicles (EVs), membrane-enclosed structures released into the extracellular milieu by tumor/host cells, are now recognized as critical drivers in the complex intercellular communication between tumor cells and the local cellular components in a hypoxic/acidic microenvironment. Understanding the intricate molecular mechanisms governing the interactions between tumor and host cells within a hypoxic and acidic microenvironment, triggered by the release of EVs, could pave the way for innovative strategies to disrupt the complex interplay of cancer cells with their microenvironment. This approach may contribute to the development of an efficient and safe therapeutic strategy to combat cancer progression. Therefore, we review the major findings on the release of EVs in a hypoxic/acidic tumor microenvironment to appreciate their role in tumor progression toward metastatic disease.

Radiotheranostic landscape: A review of clinical and preclinical development

BACKGROUND

Radiotheranostics combines diagnostic imaging with targeted radionuclide therapy, representing a transformative approach in precision oncology. Landmark approvals of Lutathera® and Pluvicto® have catalyzed significant advancements in this field, driving research into novel radionuclides, targeting strategies, and clinical applications. This review evaluates the evolving clinical and preclinical landscape of radiotheranostics, highlighting advancements, emerging trends, and persistent challenges in radionuclide therapy.

METHODS

A comprehensive analysis was performed, encompassing active clinical trials as of December 2024, sourced from ClinicalTrials.gov and TheranosticTrials.org. Preclinical developments were evaluated through a review of recent literature, focusing on innovations in radionuclide production, targeting molecules, and radiochemistry.

RESULTS

In reviewing the clinical landscape, agents targeting somatostatin receptors (SSTR) and prostate-specific membrane antigen (PSMA) still dominate the field, but new targets such as fibroblast activation protein (FAP), integrins, and gastrin-releasing peptide receptors (GRPR) are gaining traction in both clinical and preclinical development. While small molecules and peptides remain the most common radionuclide carriers, antibody-based carriers including bispecific antibodies, immunoglobin-derived antigen-binding fragments, and antibody-mimetic proteins are on the rise due to their specificity and adaptability. Innovations in radioligand design are driving a shift from agonists to antagonists, accompanied by the development of modified peptides with enhanced pharmacokinetics and tumor-targeting properties. Next-generation therapeutic radionuclides, such as the beta-emitter terbium-161 and alpha-emitters actinium-225 and lead-212, are under investigation to complement or replace lutetium-177, addressing the need for improved efficacy and reduced toxicity. Paired isotopic radionuclides are gaining popularity for their ability to optimize imaging and therapeutic dosimetry as they offer near-identical specificity, biodistribution, and metabolism. Additionally, radiohybrid systems represent an innovative approach to chelating chemically distinct radionuclide pairs within a single molecule, further enhancing flexibility in radiotheranostic design.

CONCLUSION

Radiotheranostics has transformed cancer care through its precision and adaptability, but challenges in radionuclide production, regulatory frameworks, and workforce training hinder broader adoption. Advances in isotopic pairing, next-generation radionuclides, and radiohybrid systems in preclinical and clinical settings hold promise to overcome these barriers. Collaborative efforts among academia, industry, and regulatory bodies are critical to accelerating innovation and optimizing clinical outcomes.

Recent advances of anti-tumor nano-strategies via overturning pH gradient: alkalization and acidification

The acidic tumor microenvironment, a hallmark of many solid tumors, is primarily induced by the high glycolytic rate of tumor cells. To avoid acidosis, tumor cells ingeniously maintain an acidic extracellular pH while keeping a relatively alkaline intracellular pH. Overturning the unique pH gradient of tumor cells has exhibited to be a viable approach for cancer therapy. In this review, the formation and regulatory mechanisms of the acidic microenvironment in solid tumors will be firstly outlined. Subsequently, we will comprehensively summarize the latest advancements in anti-tumor therapy via using nanomedicines to manipulate the tumor pH gradient, including acidifying intracellular environment and alkalizing extracellular environment. Following this, we will discuss the future potential of strategies employing nanomedicines to reverse tumor pH gradient. This review aims to foster research on therapeutic approaches targeting the pH regulation of solid tumors and holds an optimistic outlook for the future development of this field.

Design, Synthesis, Anticancer Screening, and Mechanistic Study of Spiro-N-(4-sulfamoyl-phenyl)-1,3,4-thiadiazole-2-carboxamide Derivatives

The present study aims to create spiro-N-(4-sulfamoyl-phenyl)-1,3,4-thiadiazole-2-carboxamide derivatives with anticancer activities. The in vitro anticancer evaluation showed that only the novel spiro-acenaphthylene tethered-[1,3,4]-thiadiazole (compound 1) exhibited significant anticancer efficacy as a selective inhibitor of tumor-associated isoforms of carbonic anhydrase. Compound 1 demonstrated considerable efficacy against the renal RXF393, colon HT29, and melanoma LOX IMVI cancer cell lines, with IC50 values of 7.01 ± 0.39, 24.3 ± 1.29, and 9.55 ± 0.51 µM, respectively. In comparison, doxorubicin exhibited IC50 values of 13.54 ± 0.82, 13.50 ± 0.71, and 6.08 ± 0.32 µM for the corresponding cell lines. Importantly, compound 1 exhibited lower toxicity to the normal WI 38 cell line than doxorubicin, with IC50 values of 46.20 ± 2.59 and 18.13 ± 0.93 µM, respectively, indicating greater selectivity of the target compound compared to the standard anticancer agent doxorubicin. Also, mechanistic experiments demonstrated that compound 1 exhibits inhibitory activity against human carbonic anhydrase hCA IX and XII, with IC50 values of 0.477 ± 0.03 and 1.933 ± 0.11 μM, respectively, indicating enhanced selectivity for cancer-associated isoforms over cytosolic isoforms hCA I and II, with IC50 values of 7.353 ± 0.36 and 12.560 ± 0.74 μM, respectively. Cell cycle studies revealed that compound 1 caused G1 phase arrest in RXF393 cells, and apoptosis experiments verified a substantial induction of apoptosis with significant levels of early and late apoptosis, as well as necrosis (11.69%, 19.78%, and 3.66%, respectively), comparable to those induced by the conventional cytotoxic agent doxorubicin, at 9.91%, 23.37%, and 6.16%, respectively. Molecular docking experiments confirmed the strong binding affinity of compound 1 to the active sites of hCA IX and XII, highlighting significant interactions with zinc-binding groups and hydrophobic residues. These findings underscore the target compound's potential as a viable anticancer agent via targeting CA.

Predicting Early Death in Head and Neck Cancer-A Pilot Study

Background: The aim of this study was to evaluate biomarkers and biological characteristics of tumor biopsies from patients with head and neck cancer (HNC) to assess the risk of early death. Furthermore, we analyzed whether any combination of markers could be used for the prognostication of death within six months after cancer diagnosis. Materials and Methods: Patients diagnosed with HNC, receiving curative treatment decision at a multidisciplinary tumor board meeting, and who died within six months of diagnosis were included in this study. Nine patients who died within six months from diagnosis were identified and matched according to the tumor site and stage to seventeen patients who survived for at least two years. Results: The expression of markers was compared between the early-death patients and survivors. There was significantly higher Ki-67 expression in patients who died within six months than in those surviving for two years, with a mean difference of 21% (p = 0.038). A significant difference in cytoplasmic survivin expression was noted where early-death patients had increased expression compared to the survivors (p = 0.021). Furthermore, the intensity of survivin staining differed between the groups (p = 0.006). Conclusions: The results of this pilot study indicate that Ki67 and survivin could be potential prognostic biomarkers for early death in patients with HNC and possibly included in a panel of prognostic markers of value for treatment decision making.

A photo-triggered dual-gas donor of nitric oxide and hydrogen sulfide with fluorescence for real-time monitoring of its release

Multi-gaseous signal molecules play a significant role in regulating various physiological and pathological processes. Therefore, studying the synergistic effects of multi-gas donors on biological systems is essential. However, different types of gas donors vary significantly in terms of gas release, including location, dose, and flux. These variations can have a dramatic impact on the biological effects of the gases and require further analysis for confirmation. Thus, a controllable dual-gas donor that enables self-reporting would be valuable for studying the biological effects of two species of gaseous signal molecules. Herein, we present a novel photo-triggered donor, NHD545, which releases nitric oxide and hydrogen sulfide simultaneously. Furthermore, the dual-gas release from this donor is accompanied by turn-on fluorescence, which could be utilized to monitor the NO and H2S release by microscopy. With NHD545, it is convenient to investigate the synergistic effect of dual-gas bioavailability in vitro.

Carbonic anhydrase IX inhibition as a path to treat neuroblastoma

BACKGROUND AND PURPOSE

Tumour hypoxia frequently presents a major challenge in the treatment of neuroblastoma (NBL). The neuroblastoma cells produce carbonic anhydrase IX (CA IX), an enzyme crucial for the survival of cancer cells in low-oxygen environments.

EXPERIMENTAL APPROACH

We designed and synthesised a novel high-affinity inhibitor of CA IX. The highest to-date. The affinities were determined for all human catalytically active CA isozymes showing significant selectivity for CA IX over other isozymes. The inhibitor effect on neuroblastoma cancer cell growth was determined in vitro and in vivo via a mice xenograft model.

KEY RESULTS

The novel designed inhibitor effectively mitigated the acidification induced by CA IX and reduced spheroid growth under hypoxic conditions in the SK-N-AS cell line. It also diminished the secretion of pro-tumour chemokines IL-8 (CXCL2) and CCL2. When we combined this novel CA IX inhibitor with a compound that inhibits the chemokine receptor CCR2 protein activity, we observed a reduction in mouse tumour growth. The combined treatment also prompted tumours to exhibit adaptive resistance by producing higher levels of vascular endothelial growth factor receptors (VEGFR) and other compensatory signals.

CONCLUSIONS AND IMPLICATIONS

This research underscores the pivotal role of CA IX in cancer and the potential of a novel CA IX inhibitor-based combination intervention therapy for neuroblastoma treatment.

The potential of targeted radionuclide therapy to treat hypoxic tumor cells

Tumor hypoxia contributes to cancer progression and therapy resistance. Several strategies have been investigated to relieve tumor hypoxia, of which some were successful. However, their clinical application remains challenging and therefore they are not used in daily clinical practice. Here, we review the potential of targeted radionuclide therapy (TRT) to eradicate hypoxic cancer cells. We present an overview of the published TRT strategies using β--particles, α-particles, and Auger electrons. Altogether, we conclude that α-particle emitting radionuclides are most promising since they can cause DNA double strand breaks independent of oxygen levels. Future directions for research are addressed, including more adequate in vitro and in vivo models to proof the potential of TRT to eliminate hypoxic cancer cells. Furthermore, dosimetry and radiobiology are identified as key to better understand the mechanism of action and dose-response relationships in hypoxic tumor areas. Finally, we can conclude that in order to achieve long-term anti-tumor efficacy, TRT combination treatment strategies may be necessary.

Quinolines: A Promising Heterocyclic Scaffold for Cancer Therapeutics

The quinoline scaffold is a widely recognized heterocycle with applications across various disease categories, ranging from malaria and viral infections to bacterial infections, high cholesterol, and even tumors. Consequently, quinoline plays a crucial role in the development of new drugs, and the field greatly benefits from advancements in computer-aided drug design. This review aims to provide insights into the evolution of quinoline and its derivatives, offering a comprehensive exploration of both marketed and developing drugs. Furthermore, the function and mechanism of quinoline compounds are introduced. Many studies rely on cell experiments to demonstrate drug cytotoxicity. In the concluding section of this review, the interaction between quinoline compounds and targets is simulated using computer-aided drug design methods. A thorough analysis is conducted on the potential influencing factors affecting the binding state between quinoline compounds and targets. Notably, the Pi-Alkyl interaction emerges as a significant contributor, while hydrogen bonding is identified as a pivotal bond in these interactions. This review serves as a valuable overview of the potential contributions of quinoline compounds to cancer treatment. It seamlessly combines the essential functions of marketed quinoline drugs with the promise held by emerging quinoline-based compounds. Additionally, the simulation of interactions between quinoline compounds and proteins through computer-aided design enhances our understanding of these compounds' efficacy.

Targeting the lung tumour stroma: harnessing nanoparticles for effective therapeutic interventions

Lung cancer remains an influential global health concern, necessitating the development of innovative therapeutic strategies. The tumour stroma, which is known as tumour microenvironment (TME) has a central impact on tumour expansion and treatment resistance. The stroma of lung tumours consists of numerous cells and molecules that shape an environment for tumour expansion. This environment not only protects tumoral cells against immune system attacks but also enables tumour stroma to attenuate the action of antitumor drugs. This stroma consists of stromal cells like cancer-associated fibroblasts (CAFs), suppressive immune cells, and cytotoxic immune cells. Additionally, the presence of stem cells, endothelial cells and pericytes can facilitate tumour volume expansion. Nanoparticles are hopeful tools for targeted drug delivery because of their extraordinary properties and their capacity to devastate biological obstacles. This review article provides a comprehensive overview of contemporary advancements in targeting the lung tumour stroma using nanoparticles. Various nanoparticle-based approaches, including passive and active targeting, and stimuli-responsive systems, highlighting their potential to improve drug delivery efficiency. Additionally, the role of nanotechnology in modulating the tumour stroma by targeting key components such as immune cells, extracellular matrix (ECM), hypoxia, and suppressive elements in the lung tumour stroma.

Value of [68Ga]Ga-NYM046 PET/CT, in Comparison with 18F-FDG PET/CT, for Diagnosis of Clear Cell Renal Cell Carcinoma

This study aimed to investigate the diagnostic efficacy of [68Ga]Ga-NYM046 PET/CT in animal models and patients with clear cell renal cell carcinoma (ccRCC) and to compare its performance with that of 18F-FDG PET/CT. Methods: The in vivo biodistribution of [68Ga]Ga-NYM046 was evaluated in mice bearing OS-RC-2 xenografts. Twelve patients with ccRCC were included in the study; all completed paired [68Ga]Ga-NYM046 PET/CT and 18F-FDG PET/CT. The diagnostic efficacies of these 2 PET tracers were compared. Moreover, the positive rate of carbonic anhydrase IX in the pathologic tissue sections was compared with the SUVmax obtained by PET/CT. Results: The tumor accumulation of [68Ga]Ga-NYM046 at 1 h after injection in OS-RC-2 xenograft tumor models was 7.21 ± 2.39 injected dose per gram of tissue. Apart from tumors, the kidney and stomach showed high-uptake distributions. In total, 9 primary tumors, 96 involved lymph nodes, and 147 distant metastases in 12 patients were evaluated using [68Ga]Ga-NYM046 and 18F-FDG PET/CT. Compared with 18F-FDG PET/CT, [68Ga]Ga-NYM046 PET/CT detected more primary tumors (9 vs. 1), involved lymph nodes (95 vs. 92), and distant metastases (137 vs. 127). In quantitative analysis, the primary tumors' SUVmax (median, 13.5 vs. 2.4; z = -2.668, P = 0.008) was significantly higher in [68Ga]Ga-NYM046 PET/CT. Conversely, the involved lymph nodes' SUVmax (median, 5.9 vs. 7.6; z = -3.236, P = 0.001) was higher in 18F-FDG PET/CT. No significant differences were found for distant metastases (median SUVmax, 5.0 vs. 5.0; z = -0.381, P = 0.703). Higher [68Ga]Ga-NYM046 uptake in primary tumors corresponded to higher expression of carbonic anhydrase IX, with an R 2 value of 0.8274. Conclusion: [68Ga]Ga-NYM046 PET/CT offers a viable strategy for detecting primary tumors, involved lymph nodes, and distant metastases in patients with ccRCC.

Targeting CA9 restricts pancreatic cancer progression through pH regulation and ROS production

PURPOSE

Lactate is a key metabolite produced by glycolytic metabolism, yet it also serves as an energy source for cancer cells. Lactate accumulation in the tumor microenvironment (TME) has been demonstrated to correlate with immunosuppressive TME and tumor progression. As a highly glycolytic tumor, it is crucial to decipher the underlying mechanism in pancreatic ductal adenocarcinoma (PDAC).

METHODS

Bioinformation analysis was used to identify lactate mediated carbonic anhydrase IX (CA9) upregulation. CCK-8, colony formation and mouse xenograft assay were utilized to study the effect of CA9 in PDAC. ECAR, OCR and pHi measurement confirmed the impacts of CA9 in Warburg phenotype. Using confocal microscopy, flow cytometry, qRT-PCR, co-IP, we validated the signaling pathways in PDAC to regulate reactive oxygen species (ROS) production.

RESULTS

We confirmed that CA9 is highly expressed in PDAC and positively regulated by lactate levels. CA9 can enhance the proliferative and migratory capabilities of PDAC cells. Pharmacologic inhibition or knockdown of CA9 significantly reduce pHi, increase the intracellular lactate and reverse the Warburg phenotype. The intracellular lactate accumulation caused by CA9 knockdown upregulates ROS and mitochondrial dysfunction. Furthermore, it was discovered that the competitive binding of CA9 with FUS inhibits the facilitation of FUS on NOX4 pre-mRNA splicing.

CONCLUSION

Collectively, our data illustrate that CA9 has a direct regulatory role in pHi homeostasis and ROS production, providing a potential therapeutic target for PDAC treatment.

Combination of Carbonic Anhydrase Isoform IX Inhibitors and Gefitinib Suppresses on the Invasive Potential of Non-Small Cell Lung Cancer Cells

Human carbonic anhydrase IX (CAIX) plays a key role in maintaining pH homeostasis of malignant neoplasms, thus creating a favorable microenvironment for the growth, invasion, and metastasis of tumor cells. Recent studies have established that inhibition of CAIX expressed on the surface of tumor cells significantly increases the efficacy of classical chemotherapeutic agents and makes it possible to suppress the resistance of tumor cells to chemotherapy, as well as to increase their sensitivity to drugs (in particular, to reduce the required dose of cytostatic agents). In this work, we studied the ability of new CAIX inhibitors based on substituted 1,2,4-oxadiazole-containing primary aromatic sulfonamides, to potentiate the cytostatic effect of gefitinib (selective inhibitor of epidermal growth factor receptor tyrosine kinase domain) under hypoxic conditions. We investigated a combined effect of gefitinib and CAIX inhibitors 4-(3-phenyl-1,2,4-oxadiazol-5-yl)thiophene-2-sulfonamide (1), 4-(5-(thiophene-3-yl)-1,2,4-oxadiazol-3-yl)benzenesulfonamide (2), 4-(3-(pyridin-2-yl)-1,2,4-oxadiazol-5-yl)thiophene-2-sulfonamide (3), and 4-(5-methyl-1,2,4-oxadiazol-3-yl)benzenesulfonamide (4) on gefitinib cytotoxicity, cell proliferation, activation of caspases-3/7, and cell cycle control in human lung adenocarcinoma A549 cells. It was found that the combinations of compounds 1 and 2 with gefitinib suppressed the invasive potential of A549 cells. Compound 1 had the greatest effect and can be considered as a promising candidate for further research.

Transcriptomic response of overexpression ZNF32 in breast cancer cells

Breast cancer is one of the deadliest malignancies in women worldwide. Zinc finger protein 32 (ZNF32) has been reported to be involved in autophagy and stem cell like properties of breast cancer cells. However, the effects, mechanisms, target genes and pathways of ZNF32 in breast cancer development have not been fully explored. In this study, stable ZNF32 overexpression breast cancer cell line was generated, and we used RNA-seq and RT-qPCR to quantify and verify the changes in transcription levels in breast cancer cells under ZNF32 overexpression. Transcriptome analysis showed that high expression of ZNF32 is accompanied by changes in downstream focal adhesion, ECM-receptor interaction, PI3K-AKT, HIPPO and TNF signaling pathways, which are critical for the occurrence and development of cancer. Multiple differentially expressed genes (DEGs) were significantly involved in cell proliferation, adhesion and migration, including 11 DEGs such as CA9, CRLF1 and ENPP2P with fundamental change of regulation modes. All the 11 DEGs were validated by RT-qPCR, and 9 of them contained potential transcriptional binding sequences of ZNF32 in their promoter region. This study provides a holistic perspective on the role and molecular mechanism of ZNF32 in breast cancer progression.

Intrinsic Synergy and Selectivity for the Inhibition of Cancer Cell Growth Generated by a Polymer Ligand of Proximal Enzymes

A fundamental understanding of the design of polymer ligands of proximal enzymes is essential for the precise targeting of cancer cells, but it is still in its infancy. In this study, we systematically investigated the contribution of the chain length, ligand density, and ligand ratio of proximal enzyme-targeted polymers to the efficacy, synergy, and selectivity for the inhibition of cancer cell proliferation. The results revealed that employing a moderate chain length as a scaffold allowed for an intrinsically high efficacy and synergy of proximal enzyme-targeted polymers, in contrast to single enzyme-targeted polymers that prefer longer chain length for efficacy. The synergy obtained in proximal enzyme targeting was not provided by the combination of the corresponding small molecules. Moreover, the maturation of the synergistic efficacy of the proximal enzyme-targeted polymers also improved selectivity. This study proposes a rational design for polymer inhibitors and/or ligands for cancer cells with a high efficacy and selectivity.

Unraveling the mechanism of carbonic anhydrase IX inhibition by alkaloids from Ruta chalepensis: A synergistic analysis of in vitro and in silico data

Due to the pivotal role of carbonic anhydrase IX (CA IX) in pathological conditions, there's a pressing need for novel inhibitors to improve patient outcomes and clinical management. Herein, we investigated the inhibitory efficacy of six alkaloids from Ruta chalepensis against CA IX through in vitro inhibition assay and computational modeling. Skimmianine and maculosidine displayed significant inhibitory activity in vitro, with low IC50 values of 105.2 ± 3.2 and 295.7 ± 14.1 nM, respectively. Enzyme kinetics analyses revealed that skimmianine exhibited a mixed inhibition mode, contrasting with the noncompetitive inhibition mechanism observed for the reference drug (acetazolamide), as indicated by intersecting lines in the Lineweaver-Burk plots. The findings of docking calculations revealed that skimmianine and maculosidine exhibited extensive polar interactions with the enzyme. These alkaloids demonstrate substantial binding interactions and occupy identical binding site as acetazolamide, thereby enhancing their efficacy as inhibitors of CA IX. Utilizing a 100 ns molecular dynamics (MD) simulation, the dynamic interactions between isolated alkaloids and CA IX were intensively assessed. Analysis of diverse MD parameters revealed that skimmianine and maculosidine displayed consistent trajectories and notable energy stabilization during their interaction with CA IX. The findings of MM/PBSA analysis depicted the minimum binding free energy for skimmianine and maculosidine. In addition, the Potential Energy Landscape (PEL) analysis revealed distinct and stable conformational states for the CA IX-ligand complexes, with Skimmianine showing the most stable and lowest energy configuration. These computational findings align with experimental results, emphasizing the potential efficacy of skimmianine and maculosidine as inhibitors of CA IX.

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.

A pH-Responsive Ti-Based Local Drug Delivery System for Osteosarcoma Therapy

Osteosarcoma is one of the major bone cancers, especially for youngsters. The current treatment usually requires systemic chemotherapy and the removal of bone tumors. Titanium (Ti)-based implants can be modified as local drug delivery (LDD) systems for controllable and localized chemotherapeutic drug release. In this work, a pH-responsive Ti-based LDD prototype was designed by introducing polydopamine (PDA) to release doxorubicin (DOX) around osteosarcoma cells with low pH. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and a contact angle meter were applied for surface characterization. Both direct and indirect cell culture modes were performed for biocompatibility and biofunction assessments. The results indicate that the Ti-based LDD prototype exhibits significant pH-dependent DOX release. The cumulative release can reach up to approximately 40% at pH = 6.0 after 72 h, but only around 20% at pH = 7.4. The Ti-based LDD implant shows good biocompatibility with approximately 93% viability of MC3T3 cells after direct culture in vitro for 24 h. Both direct and indirect culture modes verify the good anti-osteosarcoma function of the LDD implant, which should be attributed to the pH-responsive release of DOX.

Retrospective study assessing the role of the androgen receptor in clear cell renal cell cancer patients treated with VEGFR inhibitors in monotherapy

BACKGROUND AND PURPOSE

Despite that incorporating antiangiogenic in combination with immune-checkpoint inhibitors as the standard first-line treatment for advanced clear cell renal cell cancer (ccRCC) yields promising outcomes, these regimens often lead to significant toxicity. However, a subgroup of patients has shown responsiveness to VEGFR tyrosine-kinase inhibitors (TKIs) in monotherapy, leading to the question of whether employing combination therapies can significantly enhance overall survival in all patients over monotherapy. Thus, we aim to identify gene expression signatures that can predict TKI response within subpopulations that might benefit from single-agent therapies, to minimize unnecessary exposure to combination therapies and their associated toxicities, as well as to discover new potential therapeutic targets to improve ccRCC treatment. Based on prior data, the androgen receptor (AR) might meet both conditions.

PATIENTS AND METHODS

We evaluated the association between AR expression, assessed through NanoString® technology-derived mRNA counts, and the clinical outcomes of 98 ccRCC patients treated with first-line antiangiogenics and determined its association with other genes implicated in ccRCC tumorigenesis.

RESULTS

Higher AR-expression correlates significantly with better prognosis and survival based on the MSKCC risk score, and longer PFS. Furthermore, we have identified a gene set signature associated with AR-overexpression and several genes involved in angiogenesis and transcriptional targets of the hypoxia-inducible factor, a cornerstone of ccRCC.

CONCLUSIONS

AR-overexpression and its association with other genes could favor a transcriptomic signature set to aid in identifying patients suitable for TKI in monotherapy, rather than aggressive combinations, enhancing thus, precision and personalized therapeutic decisions.

Phytochemical, biological, and computational investigations of Ephedra alata Decne. growing in salinity conditions of Arabian Peninsula

Ephedra alata Decne is a medicinal plant widely used in traditional medicine for the management of bronchial asthma and cancer. Phytochemical analysis and biological activities, including antioxidant and anticancer effects, were investigated in the current work as new findings for the plant E. alata, a species growing wildly in the marsh and saline environments of the central area of Saudi Arabia. The Ultra Pressure Liquid Chromatography coupled with Electron spray ionization-Quadropole-Time of flight (UPLC-ESI-Q-TOF) system was used for the phytochemical analysis of the plant constituents. In addition, Polyphenolic profiling including the total phenolic (TPC) and flavonoid (TFC) contents of the plant extracts were measured. Phenolic acids were found at the highest relative percentages among all the identified compounds and were measured at 66.07 mg GAE (Gallic acid equivalent). The UPLC analysis of the E. alata extract indicated the presence of chlorogenic acid, syringic acid, caffeic acid, vanillic acid, rosmarinic acid, umbelliferone, isorhoifolin, and apigenin at the highest relative percentages. Mineral analysis indicated that the microelement content of E. alata was relatively low, except for magnesium (Mg). In vitro antioxidant assays revealed the ability of the plant to scavenge DPPH free radicals, reduced molybdenum ions, and ferrous at levels of 14.63, 19.97, and 27.78 mg Trolox equivalents, respectively. The extract induced transition metal chelation at 31.36 mg EDTA equivalents. The extract induced cytotoxic effects against MDA-231 and A549 cell lines at IC50 levels of 25.31 and 39.81 µg/mL, respectively. The plant extract inhibited the colonization and migration of cancer cells as part of its potential anticancer effects. In addition, major E. alata constituents like isorhoifolin, chlorogenic acid, apigenin, and rosmarinic acid exhibited the lowest binding energy to the CAIX enzyme at - 8.41, - 6.64, - 6.32, and - 6.26 kcal/mol, respectively, compared to the binding energy (- 7.72 kcal/mol) of the co-crystallized ligand (Y0R). The docking results further supported the selection of the CAIX enzyme as a standard predictive therapeutic target, since it exhibited significant binding interactions with the major constituents of the plant.

Hydrogen Sulfide-Releasing Carbonic Anhydrase Inhibitors Effectively Suppress Cancer Cell Growth

This study proposes a novel therapeutic strategy for cancer management by combining the antitumor effects of hydrogen sulfide (H2S) and inhibition of carbonic anhydrases (CAs; EC 4.2.1.1), specifically isoforms IV, IX, and XII. H2S has demonstrated cytotoxicity against various cancers at high concentrations. The inhibition of tumor-associated CAs leads to lethal intracellular alkalinization and acidification of the extracellular tumor microenvironment and restores tumor responsiveness to the immune system, chemotherapy, and radiotherapy. The study proposes H2S donor-CA inhibitor (CAI) hybrids for tumor management. These compounds effectively inhibit the target CAs, release H2S consistently, and exhibit potent antitumor effects against MDA-MB-231, HCT-116, and A549 cancer cell lines. Notably, some compounds display high cytotoxicity across all investigated cell lines. Derivative 30 shows a 2-fold increase in cytotoxicity (0.93 ± 0.02 µM) under chemically induced hypoxia in HCT-116 cells. These compounds also disturb the cell cycle, leading to a reduction in cell populations in G0/G1 and S phases, with a notable increase in G2/M and Sub-G1. This disruption is correlated with induced apoptosis, with fold increases of 37.2, 24.5, and 32.9 against HCT-116 cells and 14.2, 13.1, and 19.9 against A549 cells compared to untreated cells. These findings suggest the potential of H2S releaser-CAI hybrids as effective and versatile tools in cancer treatment.

Development of carbonic anhydrase IX-targeting molecular-targeted photodynamic therapy

The efficacy of molecular-targeted photodynamic therapy (MT-PDT) targeting carbonic anhydrase (CA) IX, a cancer-specific molecule, was demonstrated. CA ligand-directed photosensitizers 1-3 were evaluated for their ability to deactivate CAIX protein in cells. Compounds 2 and 3 selectively deactivated CAIX protein under 540 nm light without affecting internal standard proteins. Mechanistic studies revealed that compound 3 not only induced CAIX-selective light inactivation via singlet oxygen but also induced cell membrane damage, resulting in an anti-tumor effect. In vivo studies of CAIX-targeting MT-PDT revealed that treatment with compound 3 followed by light irradiation exhibited remarkable anti-tumor activity, leading to tumor degeneration and necrosis.

Hypoxia-induced epigenetic regulation of breast cancer progression and the tumour microenvironment

The events that control breast cancer progression and metastasis are complex and intertwined. Hypoxia plays a key role both in oncogenic transformation and in fueling the metastatic potential of breast cancer cells. Here we review the impact of hypoxia on epigenetic regulation of breast cancer, by interfering with multiple aspects of the tumour microenvironment. The co-dependent relationship between oxygen depletion and metabolic shift to aerobic glycolysis impacts on a range of enzymes and metabolites available in the cell, promoting posttranslational modifications of histones and chromatin, and changing the gene expression landscape to facilitate tumour development. Hormone signalling, particularly through ERα, is also tightly regulated by hypoxic exposure, with HIF-1α expression being a prognostic marker for therapeutic resistance in ER+ breast cancers. This highlights the strong need to understand the hypoxia-endocrine signalling axis and exploit it as a therapeutic target. Furthermore, hypoxia has been shown to enhance metastasis in TNBC cells, as well as promoting resistance to taxanes, radiotherapy and even immunotherapy through microRNA regulation and changes in histone packaging. Finally, several other mediators of the hypoxic response are discussed. We highlight a link between ionic dysregulation and hypoxia signalling, indicating a potential connection between HIF-1α and tumoural Na+ accumulation which would be worth further exploration; we present the role of Ca2+ in mediating hypoxic adaptation via chromatin remodelling, transcription factor recruitment and changes in signalling pathways; and we briefly summarise some of the findings regarding vesicle secretion and paracrine induced epigenetic reprogramming upon hypoxic exposure in breast cancer. By summarising these observations, this article highlights the heterogeneity of breast cancers, presenting a series of pathways with potential for therapeutic applications.

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.

MUC16 as a serum-based prognostic indicator of prometastatic gastric cancer

Metastatic gastric cancer (GC) presents significant clinical challenges due to its poor prognosis and limited treatment options. To address this, we conducted a targeted protein biomarker discovery study to identify markers predictive of metastasis in advanced GC (AGC). Serum samples from 176 AGC patients (T stage 3 or higher) were analyzed using the Olink Proteomics Target panels. Patients were retrospectively categorized into nonmetastatic, metastatic, and recurrence groups, and differential protein expression was assessed. Machine learning and gene set enrichment analysis (GSEA) methods were applied to discover biomarkers and predict prognosis. Four proteins (MUC16, CAIX, 5'-NT, and CD8A) were significantly elevated in metastatic GC patients compared to the control group. Additionally, GSEA indicated that the response to interleukin-4 and hypoxia-related pathways were enriched in metastatic patients. Random forest classification and decision-tree modeling showed that MUC16 could be a predictive marker for metastasis in GC patients. Additionally, ELISA validation confirmed elevated MUC16 levels in metastatic patients. Notably, high MUC16 levels were independently associated with metastatic progression in T3 or higher GC. These findings suggest the potential of MUC16 as a clinically relevant biomarker for identifying GC patients at high risk of metastasis.

Carbonic anhydrase IX: An atypical target for innovative therapies in cancer

Carbonic anhydrases (CAs), are metallo-enzymes implicated in several pathophysiological processes where tissue pH regulation is required. CA IX is a tumor-associated CA isoform induced by hypoxia and involved in the adaptation of tumor cells to acidosis. Indeed, several tumor-driving pathways can induce CA IX expression, and this in turn has been associated to cancer cells invasion and metastatic features as well as to induction of stem-like features, drug resistance and recurrence. After its functional and structural characterization CA IX targeting approaches have been developed to inhibit its activity in neoplastic tissues, and to date this field has seen an incredible acceleration in terms of therapeutic options and biological readouts. Small molecules inhibitors, hybrid/dual targeting drugs, targeting antibodies and adoptive (CAR-T based) cell therapy have been developed at preclinical level, whereas a sulfonamide CA IX inhibitor and an antibody entered Phase Ib/II clinical trials for the treatment and imaging of different solid tumors. Here recent advances on CA IX biology and pharmacology in cancer, and its therapeutic targeting will be discussed.

From X-ray crystallographic structure to intrinsic thermodynamics of protein-ligand binding using carbonic anhydrase isozymes as a model system

Carbonic anhydrase (CA) was among the first proteins whose X-ray crystal structure was solved to atomic resolution. CA proteins have essentially the same fold and similar active centers that differ in only several amino acids. Primary sulfonamides are well defined, strong and specific binders of CA. However, minor variations in chemical structure can significantly alter their binding properties. Over 1000 sulfonamides have been designed, synthesized and evaluated to understand the correlations between the structure and thermodynamics of their binding to the human CA isozyme family. Compound binding was determined by several binding assays: fluorescence-based thermal shift assay, stopped-flow enzyme activity inhibition assay, isothermal titration calorimetry and competition assay for enzyme expressed on cancer cell surfaces. All assays have advantages and limitations but are necessary for deeper characterization of these protein-ligand interactions. Here, the concept and importance of intrinsic binding thermodynamics is emphasized and the role of structure-thermodynamics correlations for the novel inhibitors of CA IX is discussed - an isozyme that is overexpressed in solid hypoxic tumors, and thus these inhibitors may serve as anticancer drugs. The abundant structural and thermodynamic data are assembled into the Protein-Ligand Binding Database to understand general protein-ligand recognition principles that could be used in drug discovery.

Chip collection of hepatocellular carcinoma based on O2 heterogeneity from patient tissue

Hepatocellular carcinoma frequently recurs after surgery, necessitating personalized clinical approaches based on tumor avatar models. However, location-dependent oxygen concentrations resulting from the dual hepatic vascular supply drive the inherent heterogeneity of the tumor microenvironment, which presents challenges in developing an avatar model. In this study, tissue samples from 12 patients with hepatocellular carcinoma are cultured directly on a chip and separated based on preference of oxygen concentration. Establishing a dual gradient system with drug perfusion perpendicular to the oxygen gradient enables the simultaneous separation of cells and evaluation of drug responsiveness. The results are further cross-validated by implanting the chips into mice at various oxygen levels using a patient-derived xenograft model. Hepatocellular carcinoma cells exposed to hypoxia exhibit invasive and recurrent characteristics that mirror clinical outcomes. This chip provides valuable insights into treatment prognosis by identifying the dominant hepatocellular carcinoma type in each patient, potentially guiding personalized therapeutic interventions.

Effective Anticancer Potential of a New Sulfonamide as a Carbonic Anhydrase IX Inhibitor Against Aggressive Tumors

This study examines efficiency of a newly synthesized sulfonamide derivative 2-bromo-N-(4-sulfamoylphenyl)propanamide (MMH-1) on the inhibition of Carbonic Anhydrase IX (CA IX), which is overexpressed in many solid tumors including breast cancer. The inhibitory potential of MMH-1 compound against its four major isoforms, including cytosolic isoforms hCA I and II, as well as tumor-associated membrane-bound isoforms hCA IX and XII, was evaluated. To this context, the cytotoxic effect of MMH-1 on cancer and normal cells was tested and found to selectively affect MDA-MB-231 cells. MMH-1 reduced cell proliferation by holding cells in the G0/G1 phase (72 %) and slowed the cells' wound healing capacity. MMH-1 inhibited CA IX under both hypoxic and normoxic conditions and altered the morphology of triple negative breast cancer cells. In MDA-MB-231 cells, inhibition of CA IX was accompanied by a decrease in extracellular pH acidity (7.2), disruption of mitochondrial membrane integrity (80 %), an increase in reactive oxygen levels (25 %), and the triggering of apoptosis (40 %). In addition, the caspase cascade (CASP-3, -8, -9) was activated in MDA-MB-231 cells, triggering both the extrinsic and intrinsic apoptotic pathways. The expression of pro-apoptotic regulatory proteins (Bad, Bax, Bid, Bim, Cyt-c, Fas, FasL, TNF-a, TNF-R1, HTRA, SMAC, Casp-3, -8, P21, P27, and P53) was increased, while the expression of anti-apoptotic proteins, apoptosis inhibitor proteins (IAPs), and heat shock proteins (HSPs) (Bcl-2, Bcl-w, cIAP-2, HSP27, HSP60, HSP70, Survivin, Livin, and XIAP) was decreased. These results propose that the MMH-1 compound could triggers apoptosis in MDA-MB-231 cells via the pH/MMP/ROS pathway through the inhibition of CA IX. This compound is thought to have high potential and promising anticancer properties in the treatment of aggressive tumors.

Hypoxia-related carbonic anhydrase 9 induces serpinB9 expression in cancer cells and apoptosis in T cells via acidosis

Hypoxia is a common feature of solid tumors. However, the impact of hypoxia on immune cells within tumor environments remains underexplored. Carbonic anhydrase 9 (CA9) is a hypoxia-responsive tumor-associated enzyme. We previously noted that regardless of human CA9 (hCA9) expression, hCA9-expressing mouse renal cell carcinoma RENCA (RENCA/hCA9) presented as a "cold" tumor in syngeneic aged mice. This study delves into the mechanisms behind this observation. Gene microarray analyses showed that RENCA/hCA9 cells exhibited elevated mouse serpinB9, an inhibitor of granzyme B, relative to RENCA cells. Corroborating this, RENCA/hCA9 cells displayed heightened resistance to antigen-specific cytotoxic T cells compared with RENCA cells. Notably, siRNA-mediated serpinB9 knockdown reclaimed this sensitivity. In vivo tests showed that serpinB9 inhibitor administration slowed RENCA tumor growth, but this effect was reduced in RENCA/hCA9 tumors, even with adjunctive immune checkpoint blockade therapy. Further, inducing hypoxia or introducing the mouse CA9 gene upregulated serpinB9 expression, and siRNA-mediated knockdown of the mouse CA9 gene inhibited the hypoxia-induced induction of serpinB9 in the original RENCA cells. Supernatants from RENCA/hCA9 cultures had lower pH than those from RENCA, suggesting acidosis. This acidity enhanced serpinB9 expression and T cell apoptosis. Moreover, coculturing with RENCA/hCA9 cells more actively prompted T cell apoptosis than with RENCA cells. Collectively, these findings suggest hypoxia-associated CA9 not only boosts serpinB9 in cancer cells but also synergistically intensifies T cell apoptosis via acidosis, characterizing RENCA/hCA9 tumors as "cold."

Preclinical Characterization of DPI-4452: A 68Ga/177Lu Theranostic Ligand for Carbonic Anhydrase IX

The membrane protein carbonic anhydrase IX (CAIX) is highly expressed in many hypoxic or von Hippel-Lindau tumor suppressor-mutated tumor types. Its restricted expression in healthy tissues makes CAIX an attractive diagnostic and therapeutic target. DPI-4452 is a CAIX-targeting cyclic peptide with a DOTA cage, allowing radionuclide chelation for theranostic purposes. Here, we report CAIX expression in multiple tumor types and provide in vitro and in vivo evaluations of 68Ga-labeled DPI-4452 ([68Ga]Ga-DPI-4452) and 177Lu-labeled DPI-4452 ([177Lu]Lu-DPI-4452). Methods: CAIX expression was assessed by immunohistochemistry with a panel of tumor and healthy tissues. The molecular interactions of complexed and uncomplexed DPI-4452 with CAIX were assessed by surface plasmon resonance and cell-binding assays. In vivo characterization of radiolabeled and nonradiolabeled DPI-4452 was performed in HT-29 colorectal cancer (CRC) and SK-RC-52 clear cell renal cell carcinoma (ccRCC) human xenograft mouse models and in healthy beagle dogs. Results: Overexpression of CAIX was shown in several tumor types, including ccRCC, CRC, and pancreatic ductal adenocarcinoma. DPI-4452 specifically and selectively bound CAIX with subnanomolar affinity. In cell-binding assays, DPI-4452 displayed comparably high affinities for human and canine CAIX but a much lower affinity for murine CAIX, demonstrating that the dog is a relevant species for biodistribution studies. DPI-4452 was rapidly eliminated from the systemic circulation of beagle dogs. The highest uptake of [68Ga]Ga-DPI-4452 and [177Lu]Lu-DPI-4452 was observed in the small intestine and stomach, 2 organs known to express CAIX. Uptake in other organs (e.g., kidneys) was remarkably low. In HT-29 and SK-RC-52 xenograft mouse models, both [68Ga]Ga-DPI-4452 and [177Lu]Lu-DPI-4452 showed tumor-selective uptake; in addition, [177Lu]Lu-DPI-4452 significantly reduced tumor growth. These results demonstrated the theranostic potential of DPI-4452. Conclusion: DPI-4452 selectively targets CAIX. [68Ga]Ga-DPI-4452 and [177Lu]Lu-DPI-4452 localized to tumors and were well tolerated in mice. [177Lu]Lu-DPI-4452 demonstrated strong tumor growth inhibition in 2 xenograft mouse models. Thus, the 2 agents potentially provide a theranostic approach for selecting and treating patients with CAIX-expressing tumors such as ccRCC, CRC, and pancreatic ductal adenocarcinoma.

Design, synthesis and mechanism study of coumarin-sulfonamide derivatives as carbonic anhydrase IX inhibitors with anticancer activity

In this study, twenty-nine coumarin-3-sulfonamide derivatives, twenty-seven of which are original were designed and synthesized. Cytotoxicity assay indicated that most of these derivatives exhibited moderated to good potency against A549 cells. Among them, compound 8q showed potent inhibition against the four tested cancer cell lines, especially A549 cells with IC50 value of 6.01 ± 0.81 μM, and much lower cytotoxicity on the normal cells was observed compared to the reference compounds. Bioinformatics analysis revealed human carbonic anhydrase IX (CAIX) was highly expressed in lung adenocarcinoma (LUAD) and associated with poor prognosis. The inhibitory activity of compound 8q against CAIX was assessed by using molecular docking and molecular dynamics simulations, which revealed prominent interactions of both compound 8q and CAIX at the active site and their high affinity. The results of ELISA assays verified that compound 8q possessed strong inhibitory activity against CAIX and high subtype selectivity, and could also down-regulate the expression of CAIX in A549 cells. Furthermore, the significant inhibitory effects of compound 8q on the migration and invasion of A549 cells were also found. After treatment with compound 8q, intracellular reactive oxygen species (ROS) levels increased and mitochondrial membrane potential (MMP) decreased. Mechanistic investigation using western blotting revealed compound 8q exerted the anti-migrative and anti-invasive effects probably through mitochondria-mediated PI3K/AKT pathway by targeting CAIX. In summary, coumarin-3-sulfonamide derivatives were developed as potential and effective CAIX inhibitors, which were worthy of further investigation.

Blockade of phosphodiesterase 5 by sildenafil reduces tumor growth and potentiates tumor-killing ability of cisplatin in vivo against T cell lymphoma: Implication of modulated apoptosis, reactive oxygen species homeostasis, glucose metabolism, and pH regulation

In the past years, PDE5 has emerged as a promising therapeutic target for many cancers due to its highly upregulated expression. Interestingly, a recent in vitro study by our group has shown the antitumor and chemopotentiating action of sildenafil against T cell lymphoma. Our study showed that lower doses of sildenafil (50 μM) and cisplatin (0.5 μg/mL) exhibited 4% and 23% cytotoxicity against HuT78 cells, respectively, which was dramatically increased up to 50% when treated with both. Hence, the present study was designed to evaluate the antitumor and chemo-potentiating action of sildenafil in a murine model of T cell lymphoma (popularly called as Dalton's lymphoma [DL]). In the present study, DL-bearing mice were administered with vehicle (PBS), sildenafil (5 mg/kg bw), cisplatin (5 mg/kg bw), and sildenafil and cisplatin followed by evaluation of their impact on tumor growth by analyzing various parameters. The apoptosis was assessed by Wright-Giemsa, annexin-V, and DAPI staining. Reactive oxygen species (ROS) level was examined through DCFDA staining. The expression of genes and proteins were estimated by RT-PCR and Western blotting, respectively. The experimental findings of the study demonstrate for the first time that sildenafil inhibits tumor growth and potentiates tumor inhibitory ability of cisplatin by altering apoptosis, glycolysis, ROS homeostasis, and pH regulation in T cell lymphoma-carrying host. In addition, our investigation also showed amelioration of tumor-induced liver and kidney damage by sildenafil. Overall, the experimental data of our study strongly advocate the use and repurposing of SDF in designing promising chemotherapeutic regimens against malignancies of T cells.

Vanillic acid restores homeostasis of intestinal epithelium in colitis through inhibiting CA9/STIM1-mediated ferroptosis

The damage of integrated epithelial epithelium is a key pathogenic factor and closely associated with the recurrence of ulcerative colitis (UC). Here, we reported that vanillic acid (VA) exerted potent therapeutic effects on DSS-induced colitis by restoring intestinal epithelium homeostasis via the inhibition of ferroptosis. By the CETSA assay and DARTS assay, we identified carbonic anhydrase IX (CAIX, CA9) as the direct target of VA. The binding of VA to CA9 causes insulin-induced gene-2 (INSIG2) to interact with stromal interaction molecule 1 (STIM1), rather than SREBP cleavage-activating protein (SCAP), leading to the translocation of SCAP-SREBP1 from the endoplasmic reticulum (ER) to the Golgi apparatus for cleavage into mature SREBP1. The activation of SREBP1 induced by VA then significantly facilitated the transcription of stearoyl-CoA desaturase 1 (SCD1) to exert an inhibitory effect on ferroptosis. By inhibiting the excessive death of intestinal epithelial cells caused by ferroptosis, VA effectively preserved the integrity of intestinal barrier and prevented the progression of unresolved inflammation. In conclusion, our study demonstrated that VA could alleviate colitis by restoring intestinal epithelium homeostasis through CA9/STIM1-mediated inhibition of ferroptosis, providing a promising therapeutic candidate for UC.

Discovery of non-sulfonamide carbonic anhydrase IX inhibitors through structure-based virtual screening

Carbonic anhydrase IX (CA IX) is a subtype of the human carbonic anhydrase (hCA) family and exhibits high expression in various solid tumors, rendering it a promising target for tumor therapy. Currently, marketed carbonic anhydrase inhibitors (CAIs) are primarily composed of sulfonamides derivatives, which may have impeded their potential for further expansion. Therefore, we have developed a structure-based virtual screening approach to explore novel CAIs exhibiting distinctive structures and anti-tumor potential in the FDA database. In vitro experiments demonstrated that 3-pyridinemethanol (0.42 μM), procodazole (8.35 μM) and pamidronic acid (8.51 μM) exhibited inhibitory effects on CA IX activity. The binding stability and interaction mode between the CA IX and the hit compounds are further investigated through molecular dynamics simulations and binding free energy calculations. Furthermore, the ADME/Tox prediction results indicated that these compounds exhibited favorable pharmacological properties and minimal toxic side effects. Our study successfully applied computational strategies to discover three non-sulfonamide inhibitors of carbonic anhydrase IX (CA IX) that demonstrate inhibitory activity in vitro. These findings have significant implications for the development of CA IX inhibitors and anti-tumor drugs, contributing to their progress in the field.

pH regulators and their inhibitors in tumor microenvironment

As an important characteristic of tumor, acidic tumor microenvironment (TME) is closely related to immune escape, invasion, migration and drug resistance of tumor. The acidity of the TME mainly comes from the acidic products produced by the high level of tumor metabolism, such as lactic acid and carbon dioxide. pH regulators such as monocarboxylate transporters (MCTs), carbonic anhydrase IX (CA IX), and Na+/H+ exchange 1 (NHE1) expel protons directly or indirectly from the tumor to maintain the pH balance of tumor cells and create an acidic TME. We review the functions of several pH regulators involved in the construction of acidic TME, the structure and structure-activity relationship of pH regulator inhibitors, and provide strategies for the development of small-molecule antitumor inhibitors based on these targets.

The P53-P21-RB1 pathway promotes BRD4 degradation in liver cancer through USP1

Liver cancer is notoriously refractory to conventional therapeutics. Tumor progression is governed by the interplay between tumor-promoting genes and tumor-suppressor genes. BRD4, an acetyl lysine-binding protein, is overexpressed in many cancer types, which promotes activation of a pro-tumor gene network. But the underlying mechanism for BRD4 overexpression remains incompletely understood. In addition, understanding the regulatory mechanism of BRD4 protein level will shed insight into BRD4-targeting therapeutics. In this study, we investigated the potential relation between BRD4 protein level and P53, the most frequently dysregulated tumor suppressor. By analyzing the TCGA datasets, we first identify a strong negative correlation between protein levels of P53 and BRD4 in liver cancer. Further investigation shows that P53 promotes BRD4 protein degradation. Mechanistically, P53 indirectly represses the transcription of USP1, a deubiquitinase, through the P21-RB1 axis. USP1 itself is also overexpressed in liver cancer and we show USP1 deubiquitinates BRD4 in vivo and in vitro, which increases BRD4 stability. With cell proliferation assays and xenograft model, we show the pro-tumor role of USP1 is partially mediated by BRD4. With functional transcriptomic analysis, we find the USP1-BRD4 axis upholds expression of a group of cancer-related genes. In summary, we identify a functional P53-P21-RB1-USP1-BRD4 axis in liver cancer.

First-in-Human Safety, Imaging, and Dosimetry of a Carbonic Anhydrase IX-Targeting Peptide, [68Ga]Ga-DPI-4452, in Patients with Clear Cell Renal Cell Carcinoma

[68Ga]Ga-DPI-4452, a first-in-class carbonic anhydrase IX-binding radiolabeled peptide, is the imaging agent of a theranostic pair with [177Lu]Lu-DPI-4452, developed for selecting and treating patients with carbonic anhydrase IX-expressing tumors. Here, [68Ga]Ga-DPI-4452 imaging characteristics, dosimetry, pharmacokinetics, and safety were assessed in 3 patients with clear cell renal cell carcinoma. Methods: After [68Ga]Ga-DPI-4452 administration, patients underwent serial full-body PET/CT imaging. Blood and urine were sampled. Safety was monitored for 7 d after injection. Results: Tumor uptake was observed at all time points (15 min to 4 h). Across 36 lesions, the SUVmax at 1 h after administration ranged from 6.8 to 211.6 (mean, 64.6 [SD, 54.8]). The kidneys, liver, and bone marrow demonstrated low activity. [68Ga]Ga-DPI-4452 was rapidly eliminated from blood and urine. No clinically significant toxicity was observed. Conclusion: [68Ga]Ga-DPI-4452 showed exceptional tumor uptake in patients with clear cell renal cell carcinoma, with very high tumor-to-background ratios and no significant adverse events, suggesting potential diagnostic and patient selection applications.