Repurposing Sulfasalazine as a Radiosensitizer in Hypoxic Human Colorectal Cancer

Novel repurposing of sulfasalazine for the treatment of adrenocortical carcinomas, probably through the SLC7A11/xCT-hsa-miR-92a-3p-OIP5-AS1 network pathway

BACKGROUND

Recent multigenomic analysis of adrenocortical carcinomas (ACCs) identified SLC7A11/xCT as a novel biomarker. The Food and Drug Administration-approved anti-inflammatory drug, sulfasalazine (SAS), induces ferroptosis by blocking SLC7A11 expression. We hypothesize that SAS could be repurposed to target ACC cells.

METHODS

Expression of SLC7A11 and its association with ACC survival was analyzed using Gene Expression Profiling Interactive Analysis (GEPIA). The validated ACC cell lines NCI-H295R, ACC1, and ACC2 were grown in 2D culture. In vitro studies included the CellTiter-Glo assay to calculate viability, Western blot (WB) analysis for apoptosis and other target protein changes, reverse transcriptase polymerase chain reaction for steroidogenic enzyme changes, C11BODIPY for lipid peroxidation, and mass spectrometry for changes in lipids.

RESULTS

The Cancer Genome Atlas Program database analysis in GEPIA showed that SLC7A11 and linked long noncoding RNA OAP5-AS1 are highly expressed in ACC tumors versus normal adrenals (n = 77 vs 128; P < .05). This was associated with poor overall and disease-free survival with hazard ratios of 4.3 and 5.2 for SLC7A11 and 4.8 and 2.7 for OAP5-AS1, respectively. ACC cell line half-inhibitory maximum concentration values after 72-hour SAS treatment ranged from 412 nM (ACC1) to 799 nM (ACC2), and all showed cleavage of poly (ADP-ribose) polymerase, upregulation of p-Akt and p-ERK, and downregulation of GPX4 and SLC7A11 (P < .05) by WB analysis. Sphere formation, migration, and invasion assay showed inhibition, and lipid peroxidation using C11BODIPY, increase in intracellular iron, induction of oxidative stress, and significant upregulation of oxidized polyunsaturated fatty acid phospholipids (P < .05 each) by mass spectrometry suggests induction of ferroptosis.

CONCLUSION

SAS downregulates tSLC7A11 in ACCs, targets the Akt/ERK pathway and lipid metabolism, and induces cell death in vitro, warranting additional translational studies to define its therapeutic potential in ACC.

Ferroptosis, a therapeutic target for cardiovascular diseases, neurodegenerative diseases and cancer

The identification of ferroptosis represents a pivotal advancement in the field of cell death research, revealing an entirely novel mechanism of cellular demise and offering new insights into the initiation, progression, and therapeutic management of various diseases. Ferroptosis is predominantly induced by intracellular iron accumulation, lipid peroxidation, or impairments in the antioxidant defense system, culminating in membrane rupture and consequent cell death. Studies have associated ferroptosis with a wide range of diseases, and by enhancing our comprehension of its underlying mechanisms, we can formulate innovative therapeutic strategies, thereby providing renewed hope for patients.

Revisiting hydrogen peroxide as radiosensitizer for solid tumor cells

BACKGROUND AND PURPOSE

Tumor hypoxia is the principal cause of clinical radioresistance. Despite its established role as radiosensitizer, hydrogen peroxide (H2O2) encounters clinical limitations due to stability and toxicity concerns. Recent advancements in drug delivery combine H2O2 with sodium hyaluronate (SH), enabling intratumoral administration of H2O2. This study investigates the radiomodulatory pathways of Kochi Oxydol-Radiation for Unresectable Carcinomas (KORTUC) (H2O2 + SH) under hypoxia.

MATERIALS AND METHODS

CT26 and 4T1 tumor cells were exposed to H2O2, SH and KORTUC under hypoxic conditions. Toxicity levels were determined using MTT and live-cell analysis. KORTUC's radiomodulatory properties were evaluated by colony formation assay and in spheroids. Reactive oxygen species (ROS) levels, DNA damage, apoptosis and ferroptosis were analyzed using flow cytometry. Oxygen consumption rate (OCR) and mitochondrial complex activity were assessed by Seahorse Analyzer. Oxygen levels were investigated using fiber-optic sensors. The in vitro findings were validated in CT26-bearing mice.

RESULTS

KORTUC demonstrated less cytotoxicity than H2O2-alone. KORTUC radiosensitized hypoxic tumor cells in a dose-dependent manner with enhancement ratios of 3.1 (CT26) and 2.7 (4T1). Dose-dependent OCR reduction following KORTUC exposure correlated with complex I and II inhibition, accompanied by mitochondrial ROS elevation. KORTUC injection into a 2D hypoxic tumor model surged O2 levels. KORTUC radiosensitized CT26-tumors, delaying growth by 14 days.

CONCLUSIONS

SH in KORTUC mitigates H2O2 cytotoxicity. We demonstrate that KORTUC overcomes hypoxia-induced radioresistance through inhibition of OCR, via complex I- and II-blockade, leading to tumor reoxygenation. Understanding KORTUC's pathways is essential for developing effective cancer combination therapies.

Harnessing Drug Repurposing to Combat Breast Cancer by Targeting Altered Metabolism and Epithelial-to-Mesenchymal Transition Pathways

Breast cancer remains one of the most prevalent and challenging cancers to treat due to its complexity and heterogenicity. Cellular processes such as metabolic reprogramming and epithelial-to-mesenchymal transition (EMT) contribute to the complexity of breast cancer by driving uncontrolled cell division, metastasis, and resistance to therapies. Strategically targeting these intricate pathways can effectively impede breast cancer progression, thereby revealing significant potential for therapeutic interventions. Among various emerging therapeutic approaches, drug repurposing offers a promising avenue for enhancing clinical outcomes. In recent years, high-throughput screening, QSAR, and network pharmacology have been widely employed to identify promising repurposed drugs. As an outcome, several drugs, such as Metformin, Itraconazole, Pimozide, and Disulfiram, were repurposed to regulate metabolic and EMT pathways. Moreover, strategies such as combination therapy, targeted delivery, and personalized medicine were utilized to enhance the efficacy and specificity of the repurposed drugs. This review focuses on the potential of targeting altered metabolism and EMT in breast cancer through drug repurposing. It also highlights recent advancements in drug screening techniques, associated limitations, and strategies to overcome these challenges.

Ferroptosis: mechanisms and therapeutic targets

Ferroptosis is a nonapoptotic form of cell death characterized by iron-dependent lipid peroxidation in membrane phospholipids. Since its identification in 2012, extensive research has unveiled its involvement in the pathophysiology of numerous diseases, including cancers, neurodegenerative disorders, organ injuries, infectious diseases, autoimmune conditions, metabolic disorders, and skin diseases. Oxidizable lipids, overload iron, and compromised antioxidant systems are known as critical prerequisites for driving overwhelming lipid peroxidation, ultimately leading to plasma membrane rupture and ferroptotic cell death. However, the precise regulatory networks governing ferroptosis and ferroptosis-targeted therapy in these diseases remain largely undefined, hindering the development of pharmacological agonists and antagonists. In this review, we first elucidate core mechanisms of ferroptosis and summarize its epigenetic modifications (e.g., histone modifications, DNA methylation, noncoding RNAs, and N6-methyladenosine modification) and nonepigenetic modifications (e.g., genetic mutations, transcriptional regulation, and posttranslational modifications). We then discuss the association between ferroptosis and disease pathogenesis and explore therapeutic approaches for targeting ferroptosis. We also introduce potential clinical monitoring strategies for ferroptosis. Finally, we put forward several unresolved issues in which progress is needed to better understand ferroptosis. We hope this review will offer promise for the clinical application of ferroptosis-targeted therapies in the context of human health and disease.

A novel strategy to bind pyrimidine sulfonamide derivatives with odd even chains: exploration of their design, synthesis and biological activity evaluation

Based on the hybridization strategy of dominant fragments, a series of pyrimidine sulfonamide (PS) derivatives were obtained by combining the pharmacophore fragments (sulfonamide group and pyrimidine group) with different biological activities, and evaluated as a new type of anticancer drug. The compounds were evaluated for in vitro cytotoxicity against four human cancer cell lines (HeLa, HCT-116, A-549 and HepG2) and the normal human cell line L02. Compared with the anti-cancer drug 5-fluorouracil (5-FU), the antiproliferative activity of compound PS14 was close to 5-FU and it has good antitumor activity. The IC50 values were 15.13 ± 2.20, 19.87 ± 2.01, 12.64 ± 3.22, 22.20 ± 1.34 and 102.46 ± 2.27 μM, respectively. The structure activity relationship was analyzed. The antitumor activity of the compound tended to increase. When the substituents of the branch chain of sulfonamides were odd. In addition, the oil-water partition coefficient was also investigated. The logP value of PS14 was between 0 and 3, indicating that PS14 was a compound with good lipophilic property, poor water solubility and easy to be absorbed and transported through cell membrane. The anti-cancer mechanism was further studied by flow cytometry. After PS14 treated HeLa, HCT-116, A-549 and HepG2, the percentage of apoptotic cells was 45.30%, 28.2%, 31.00% and 35.20%, respectively, which was higher than that of the control 5-FU. The results of cell cycle showed that PRD2 mainly blocked the cell cycle in the S phase, thereby inhibiting cell proliferation. Furthermore, molecular docking analyzed possible interactions between the compound and the PI3Kα active site, this compound has good binding with PI3Kα. Overall, this study laid the groundwork for the development and structural modification of new pyrimidine sulfonamide drugs, and PS14 could be further developed into a cancer treatment drug.

Ferroptosis: Frenemy of Radiotherapy

Recently, it was established that ferroptosis, a type of iron-dependent regulated cell death, plays a prominent role in radiotherapy-triggered cell death. Accordingly, ferroptosis inducers attracted a lot of interest as potential radio-synergizing drugs, ultimately enhancing radioresponses and patient outcomes. Nevertheless, the tumor microenvironment seems to have a major impact on ferroptosis induction. The influence of hypoxic conditions is an area of interest, as it remains the principal hurdle in the field of radiotherapy. In this review, we focus on the implications of hypoxic conditions on ferroptosis, contemplating the plausibility of using ferroptosis inducers as clinical radiosensitizers. Furthermore, we dive into the prospects of drug repurposing in the domain of ferroptosis inducers and radiosensitizers. Lastly, the potential adverse effects of ferroptosis inducers on normal tissue were discussed in detail. This review will provide an important framework for subsequent ferroptosis research, ascertaining the feasibility of ferroptosis inducers as clinical radiosensitizers.

Ferroptosis in cancer: From molecular mechanisms to therapeutic strategies

Ferroptosis is a non-apoptotic form of regulated cell death characterized by the lethal accumulation of iron-dependent membrane-localized lipid peroxides. It acts as an innate tumor suppressor mechanism and participates in the biological processes of tumors. Intriguingly, mesenchymal and dedifferentiated cancer cells, which are usually resistant to apoptosis and traditional therapies, are exquisitely vulnerable to ferroptosis, further underscoring its potential as a treatment approach for cancers, especially for refractory cancers. However, the impact of ferroptosis on cancer extends beyond its direct cytotoxic effect on tumor cells. Ferroptosis induction not only inhibits cancer but also promotes cancer development due to its potential negative impact on anticancer immunity. Thus, a comprehensive understanding of the role of ferroptosis in cancer is crucial for the successful translation of ferroptosis therapy from the laboratory to clinical applications. In this review, we provide an overview of the recent advancements in understanding ferroptosis in cancer, covering molecular mechanisms, biological functions, regulatory pathways, and interactions with the tumor microenvironment. We also summarize the potential applications of ferroptosis induction in immunotherapy, radiotherapy, and systemic therapy, as well as ferroptosis inhibition for cancer treatment in various conditions. We finally discuss ferroptosis markers, the current challenges and future directions of ferroptosis in the treatment of cancer.

Ferroptosis: Potential opportunities for natural products in cancer therapy

Cancer cells often exhibit defects in the execution of cell death, resulting in poor clinical outcomes for patients with many cancer types. Ferroptosis is a newly discovered form of programmed cell death characterized by intracellular iron overload and lipid peroxidation in the cell membrane. Increasing evidence suggests that ferroptosis is closely associated with a wide variety of physiological and pathological processes, particularly in cancer. Notably, various bioactive natural products have been shown to induce the initiation and execution of ferroptosis in cancer cells, thereby exerting anticancer effects. In this review, we summarize the core regulatory mechanisms of ferroptosis and the multifaceted roles of ferroptosis in cancer. Importantly, we focus on natural products that regulate ferroptosis in cancer cells, such as terpenoids, polyphenols, alkaloids, steroids, quinones, and polysaccharides. The clinical efficacy, adverse effects, and drug-drug interactions of these natural products need to be evaluated in further high-quality studies to accelerate their application in cancer treatment.