CNP mediated selective toxicity on melanoma cells is accompanied by mitochondrial dysfunction

Novel doxycycline gold nanoparticles via green synthesis using PEO-PPO block copolymers for enhanced radiosensitization of melanoma

This study focuses on a green and sustainable nanoplatform for the delivery of therapeutic agents, based on gold nanoparticles (AuNPs) synthesized using PEO-PPO block copolymers (F127, F68, P85, and their F127:P85 combination) as dual-function reducing and stabilizing agents. This eco-friendly approach eliminates the need for toxic chemical reductants, adheres to green chemistry principles, and yields highly stable, biocompatible nanosystems. The resulting polymer-stabilized AuNPs were associated with doxycycline (DOXY), a mitochondrial biogenesis inhibitor with radiosensitizing properties, and characterized using UV-Vis spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), and X-ray fluorescence (XRF). The nanoparticles exhibited high colloidal stability, with tunable hydrodynamic diameters modulated by the copolymer composition. In vitro studies on A-375 and IIB-MEL-J melanoma cell lines revealed that DOXY-associated AuNPs, combined with gamma radiation (2 Gy, 137Cs), significantly enhanced radiosensitivity, reducing both cell viability and clonogenic survival. The physicochemical features of the nanosystems, particularly particle size and surface composition, influenced cellular uptake and therapeutic response. Notably, AuNPs stabilized with F127:P85 copolymer combination (∼19 nm) outperformed those with F127 (∼30 nm), despite displaying slightly higher polydispersity. Compared to Turkevich AuNPs, our copolymer-coated nanosystems demonstrated superior colloidal stability and cellular internalization. These findings highlight the potential of green-synthesized AuNPs as multifunctional, biocompatible platforms for therapeutic delivery, supporting the development of effective and environmentally responsible multimodal cancer therapies. Moreover, the simplicity, scalability, and cost-effectiveness of the synthesis process support its potential for future translational applications.

A methotrexate labelled dual metal oxide nanocomposite for long-lasting anti-cancer theranostics

We explored the feasibility of a self-assembled chitosan nanocomposite incorporating cerium oxide/nanoceria and superparamagnetic iron oxide nanoparticles (Chit-IOCO NPs), conjugated with methotrexate (MTX) and Cy5 dye, as an integrated cancer theranostic nanosystem (Chit-IOCO-MTX-Cy5). In this system, nanoceria serves as an anti-cancer agent, while the superparamagnetic iron oxide nanoparticles function as a negative contrast agent for MR imaging. This dual metal oxide nanocomposite is conjugated with MTX which is a structural analogue of folate, serving both as a targeting mechanism for folate receptors on cancer cells and as a chemotherapeutic drug. Chit-IOCO-MTX-Cy5 exhibited exceptional negative contrast in T2 and T2∗-weighted MRI, achieving a high relaxivity of 409.5 mM⁻1 s⁻1 which is superior to clinically approved agents. The nanocomposite demonstrated both pro-oxidative and antioxidative properties, significantly increasing reactive oxygen species (ROS) production in U87MG cells (1.4-fold change), which triggered apoptosis in these cancer cells. Simultaneously, it exhibited ROS scavenging activity in non-malignant endothelial cells (0.8-fold change). Intravenous infusion of Chit-IOCO-MTX-Cy5 (5 mg/kg MTX) led to significant tumor growth inhibition, indicating a synergistic enhancement of anti-cancer effects when combining MTX and nanoceria, compared to free MTX or nanoceria without MTX conjugation. Importantly, after treatment cessation, tumours in the nanocomposite group did not re-grow, while those in the free MTX group rapidly did. In vivo MR and fluorescence imaging revealed improved uptake and retention of Chit-IOCO-MTX-Cy5 in tumours compared to nanoceria without MTX. Notably, biosafety and biochemical analyses in mice showed no significant differences between the Chit-IOCO-MTX-Cy5 treatment group and control groups.

Host 5-HT affects Plasmodium transmission in mosquitoes via modulating mosquito mitochondrial homeostasis

Malaria parasites hijack the metabolism of their mammalian host during the blood-stage cycle. Anopheles mosquitoes depend on mammalian blood to lay eggs and to transmit malaria parasites. However, it remains understudied whether changes in host metabolism affect parasite transmission in mosquitoes. In this study, we discovered that Plasmodium infection significantly decreased the levels of the tryptophan metabolite, 5-hydroxytryptamine (5-HT), in both humans and mice. The reduction led to the decrease of 5-HT in mosquitoes. Oral supplementation of 5-HT to Anopheles stephensi enhanced its resistance to Plasmodium berghei infection by promoting the generation of mitochondrial reactive oxygen species. This effect was due to the accumulation of dysfunctional mitochondria caused by 5-HT-mediated inhibition of mitophagy. Elevating 5-HT levels in mouse serum significantly suppressed parasite infection in mosquitoes. In summary, our data highlight the critical role of metabolites in animal blood in determining the capacity of mosquitoes to control parasite infection.

The role of GAPDH in the selective toxicity of CNP in melanoma cells

BACKGROUND

Malignant melanoma is the most aggressive form of skin cancer with a rather poor prognosis. Standard chemotherapy often results in severe side effects on normal (healthy) cells finally being difficult to tolerate for the patients. Shown by us earlier, cerium oxide nanoparticles (CNP, nanoceria) selectively killed A375 melanoma cells while not being cytotoxic at identical concentrations on non-cancerous cells. In conclusion, the redox-active CNP exhibited both prooxidative as well as antioxidative properties. In that context, CNP induced mitochondrial dysfunction in the studied melanoma cells via generation of reactive oxygene species (primarily hydrogen peroxide (H2O2)), but that does not account for 100% of the toxicity.

AIM

Cancer cells often show an increased glycolytic rate (Warburg effect), therefore we focused on CNP mediated changes of the glucose metabolism.

RESULTS

It has been shown before that glyceraldehyde 3-phosphate dehydrogenase (GAPDH) activity is regulated via oxidation of a cysteine in the active center of the enzyme with a subsequent loss of activity. Upon CNP treatment, formation of cellular lactate and GAPDH activity were significantly lowered. The treatment of melanoma cells and melanocytes with the GAPDH inhibitor heptelidic acid (HA) decreased viability to a much higher extent in the cancer cells than in the studied normal (healthy) cells, highlighting and supporting the important role of GAPDH in cancer cells.

CONCLUSION

We identified glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as a target protein for CNP mediated thiol oxidation.

Cerium oxide nanoparticles: Chemical properties, biological effects and potential therapeutic opportunities (Review)

The chemistry of pure cerium oxide (CeO2-x) nanoparticles has been widely studied since the 1970s, especially for chemical catalysis. CeO2-x nanoparticles have been included in an important class of industrial metal oxide nanoparticles and have been attributed a range of wide applications, such as ultraviolet absorbers, gas sensors, polishing agents, cosmetics, consumer products, high-tech devices and fuel cell conductors. Despite these early applications in the field of chemistry, the biological effects of CeO2-x nanoparticles were only explored in the 2000s. Since then, CeO2-x nanoparticles have gained a spot in research related to various diseases, especially the ones in which oxidative stress plays a part. Due to an innate oxidation state variation on their surface, CeO2-x nanoparticles have exhibited redox activities in diseases, such as cancer, acting either as an oxidizing agent, or as an antioxidant. In biological models, CeO2-x nanoparticles have been shown to modulate cancer cell viability and, more recently, cell death pathways. However, a deeper understanding on how the chemical structure of CeO2-x nanoparticles (including nanoparticle size, shape, suspension, agglomeration in the medium used, pH of the medium, type of synthesis and crystallite size) influences the cellular effects observed remains to be elucidated. In the present review, the chemistry of CeO2-x nanoparticles and their impact on biological models and modulation of cell signalling, particularly focusing on oxidative and cell death pathways, were investigated. The deeper understanding of the chemical activity of CeO2-x nanoparticles may provide the rationale for further biomedical applications towards disease treatment and drug delivery purposes.

Calcein-Modified CeO2 for Intracellular ROS Detection: Mechanisms of Action and Cytotoxicity Analysis In Vitro

Cerium oxide nanoparticles (CeO2 NPs) are metal-oxide-based nanozymes with unique reactive oxygen species (ROS) scavenging abilities. Here, we studied new CeO2 NPs modified with calcein (CeO2-calcein) as an intracellular ROS inactivation/visualization theranostic agent. The molecular mechanisms of the CeO2-calcein intracellular activity, allowing for the direct monitoring of ROS inactivation in living cells, were studied. CeO2-calcein was taken up by both normal (human mesenchymal stem cells, hMSc) and cancer (human osteosarcoma, MNNG/Hos cell line) cells, and was easily decomposed via endogenous or exogenous ROS, releasing brightly fluorescent calcein, which could be quantitatively detected using fluorescence microscopy. It was shown that the CeO2-calcein has selective cytotoxicity, inducing the death of human osteosarcoma cells and modulating the expression of key genes responsible for cell redox status as well as proliferative and migration activity. Such cerium-based theranostic agents can be used in various biomedical applications.

Microfluidic-based skin-on-chip systems for safety assessment of nanomaterials

The skin is the body's largest organ, continuously exposed to and affected by natural and anthropogenic nanomaterials (materials with external and internal dimensions in the nanoscale range). This broad spectrum of insults gives rise to irreversible health effects (from skin corrosion to cancer). Organ-on-chip systems can recapitulate skin physiology with high fidelity and potentially revolutionize the safety assessment of nanomaterials. Here, we review current advances in skin-on-chip models and their potential to elucidate biological mechanisms. Further, strategies are discussed to recapitulate skin physiology on-chip, improving control over nanomaterials exposure and transport across cells. Finally, we highlight future opportunities and challenges from design and fabrication to acceptance by regulatory bodies and industry.

The Antimalarial Drug Artesunate Mediates Selective Cytotoxicity by Upregulating HO-1 in Melanoma Cells

Despite great efforts to develop new therapeutic strategies to combat melanoma, the prognosis remains rather poor. Artesunate (ART) is an antimalarial drug displaying anti-cancer effects in vitro and in vivo. In this in vitro study, we investigated the selectivity of ART on melanoma cells. Furthermore, we aimed to further elucidate the mechanism of the drug with a focus on the role of iron, the induction of oxidative stress and the implication of the enzyme heme oxygenase 1 (HO-1). ART treatment decreased the cell viability of A375 melanoma cells while it did not affect the viability of normal human dermal fibroblasts, used as a model for normal (healthy) cells. ART's toxicity was shown to be dependent on intracellular iron and the drug induced high levels of oxidative stress as well as upregulation of HO-1. Melanoma cells deficient in HO-1 or treated with a HO-1 inhibitor were less sensitive towards ART. Taken together, our study demonstrates that ART induces oxidative stress resulting in the upregulation of HO-1 in melanoma cells, which subsequently triggers the effect of ART's own toxicity. This new finding that HO-1 is involved in ART-mediated toxicity may open up new perspectives in cancer therapy.

Involvement of necroptosis in the selective toxicity of the natural compound (±) gossypol on squamous skin cancer cells in vitro

Cutaneous basal and squamous cell carcinoma reflect the first and second most common type of non-melanoma skin cancer, respectively. Especially cutaneous squamous cell carcinoma has the tendency to metastasize, finally resulting in a rather poor prognosis. Therapeutic options comprise surgery, radiation therapy, and a systemic or targeted chemotherapy. There are some good treatment results, but overall, the response rate of newly developed drugs is still modest. Drug repurposing represents an alternative approach where already available and clinically approved substances are used, which originally intended for other clinical benefits. In this context, we tested the effect of the naturally occurring polyphenolic aldehyde (±) gossypol with concentrations between 1 and 5 µM on the invasive squamous cell carcinoma cell line SCL-1 and normal human epidermal keratinocytes. Gossypol treatment up to 96 h resulted in a selective cytotoxicity of SCL-1 cells (IC50: 1.7 µM, 96 h) compared with normal keratinocytes (IC50: ≥ 5.4 µM, 96 h) which is mediated by mitochondrial dysfunction and finally leading to necroptotic cell death. Taken together, gossypol shows a high potential as an alternative anticancer drug for the treatment of cutaneous squamous cell carcinoma.

Pancreatic islet protection at the expense of secretory function involves serine-linked mitochondrial one-carbon metabolism

Type 2 diabetes is characterized by insulin hypersecretion followed by reduced glucose-stimulated insulin secretion (GSIS). Here we show that acute stimulation of pancreatic islets with the insulin secretagogue dextrorphan (DXO) or glibenclamide enhances GSIS, whereas chronic treatment with high concentrations of these drugs reduce GSIS but protect islets from cell death. Bulk RNA sequencing of islets shows increased expression of genes for serine-linked mitochondrial one-carbon metabolism (OCM) after chronic, but not acute, stimulation. In chronically stimulated islets, more glucose is metabolized to serine than to citrate, and the mitochondrial ATP/ADP ratio decreases, whereas the NADPH/NADP+ ratio increases. Activating transcription factor-4 (Atf4) is required and sufficient to activate serine-linked mitochondrial OCM genes in islets, with gain- and loss-of-function experiments showing that Atf4 reduces GSIS and is required, but not sufficient, for full DXO-mediated islet protection. In sum, we identify a reversible metabolic pathway that provides islet protection at the expense of secretory function.

Advancements in nanoparticle-based treatment approaches for skin cancer therapy

Skin cancer has emerged as the fifth most commonly reported cancer in the world, causing a burden on global health and the economy. The enormously rising environmental changes, industrialization, and genetic modification have further exacerbated skin cancer statistics. Current treatment modalities such as surgery, radiotherapy, conventional chemotherapy, targeted therapy, and immunotherapy are facing several issues related to cost, toxicity, and bioavailability thereby leading to declined anti-skin cancer therapeutic efficacy and poor patient compliance. In the context of overcoming this limitation, several nanotechnological advancements have been witnessed so far. Among various nanomaterials, nanoparticles have endowed exorbitant advantages by acting as both therapeutic agents and drug carriers for the remarkable treatment of skin cancer. The small size and large surface area to volume ratio of nanoparticles escalate the skin tumor uptake through their leaky vasculature resulting in enhanced therapeutic efficacy. In this context, the present review provides up to date information about different types and pathology of skin cancer, followed by their current treatment modalities and associated drawbacks. Furthermore, it meticulously discusses the role of numerous inorganic, polymer, and lipid-based nanoparticles in skin cancer therapy with subsequent descriptions of their patents and clinical trials.

Nanoceria: an innovative strategy for cancer treatment

Nanoceria or cerium oxide nanoparticles characterised by the co-existing of Ce³⁺ and Ce⁴⁺ that allows self-regenerative, redox-responsive dual-catalytic activities, have attracted interest as an innovative approach to treating cancer. Depending on surface characteristics and immediate environment, nanoceria exerts either anti- or pro-oxidative effects which regulate reactive oxygen species (ROS) levels in biological systems. Nanoceria mimics ROS-related enzymes that protect normal cells at physiological pH from oxidative stress and induce ROS production in the slightly acidic tumour microenvironment to trigger cancer cell death. Nanoceria as nanozymes also generates molecular oxygen that relieves tumour hypoxia, leading to tumour cell sensitisation to improve therapeutic outcomes of photodynamic (PDT), photothermal (PTT) and radiation (RT), targeted and chemotherapies. Nanoceria has been engineered as a nanocarrier to improve drug delivery or in combination with other drugs to produce synergistic anti-cancer effects. Despite reported preclinical successes, there are still knowledge gaps arising from the inadequate number of studies reporting findings based on physiologically relevant disease models that accurately represent the complexities of cancer. This review discusses the dual-catalytic activities of nanoceria responding to pH and oxygen tension gradient in tumour microenvironment, highlights the recent nanoceria-based platforms reported to be feasible direct and indirect anti-cancer agents with protective effects on healthy tissues, and finally addresses the challenges in clinical translation of nanoceria based therapeutics.

Structural, Optical, Antibacterial, and Anticancer Properties of Cerium Oxide Nanoparticles Prepared by Green Synthesis Using Morinda citrifolia Leaves Extract

Currently, new advancements in the area of nanotechnology opened up new prospects in the field of medicine that could provide us with a solution for numerous medical complications. Although a several varieties of nanoparticles is being explored to be used as nanomedicines, cerium oxide nanoparticles (CeO2 NPs) are the most attractive due to their biocompatibility and their switchable oxidation state (+3 and +4) or in other words the ability to act as prooxidant and antioxidant depending on the pH condition. Green synthesis of nanoparticles is preferred to make it more economical, eco-friendly, and less toxic. The aim of our study here is to formulate the CeO2 NPs (CeO2 NPs) using Morinda citrifolia (Noni) leaf extract and study its optical, structural, antibacterial, and anticancer abilities. Their optical and structural characterization was accomplished by employing X-ray diffractography (XRD), TEM, EDAX, FTIR, UV-vis, and photoluminescence assays. Our CeO2 NPs expressed strong antibacterial effects against Gram-positive S. aureus and S. pneumonia in addition to Gram-negative E. coli and K. pneumonia when compared with amoxicillin. The anticancer properties of the green synthesized CeO2 NPs against human acute lymphoblastic leukemia (ALL) MOLT-4 cells were further explored by the meticulous study of their ability to diminish cancer cell viability (cytotoxicity), accelerate apoptosis, escalate intracellular reactive oxygen species (ROS) accumulation, decline the mitochondria membrane potential (MMP) level, modify the cell adhesion, and shoot up the activation of proapoptotic markers, caspase-3, -8, and -9, in the tumor cells. Altogether, the outcomes demonstrated that our green synthesized CeO2 NPs are an excellent candidate for alternative cancer therapy.

How to Treat Melanoma? The Current Status of Innovative Nanotechnological Strategies and the Role of Minimally Invasive Approaches like PTT and PDT

Melanoma is the most aggressive type of skin cancer, the incidence and mortality of which are increasing worldwide. Its extensive degree of heterogeneity has limited its response to existing therapies. For many years the therapeutic strategies were limited to surgery, radiotherapy, and chemotherapy. Fortunately, advances in knowledge have allowed the development of new therapeutic strategies. Despite the undoubted progress, alternative therapies are still under research. In this context, nanotechnology is also positioned as a strong and promising tool to develop nanosystems that act as drug carriers and/or light absorbents to potentially improve photothermal and photodynamic therapies outcomes. This review describes the latest advances in nanotechnology field in the treatment of melanoma from 2011 to 2022. The challenges in the translation of nanotechnology-based therapies to clinical applications are also discussed. To sum up, great progress has been made in the field of nanotechnology-based therapies, and our understanding in this field has greatly improved. Although few therapies based on nanoparticulate systems have advanced to clinical trials, it is expected that a large number will come into clinical use in the near future. With its high sensitivity, specificity, and multiplexed measurement capacity, it provides great opportunities to improve melanoma treatment, which will ultimately lead to enhanced patient survival rates.

ROS-Mediated Anti-Angiogenic Activity of Cerium Oxide Nanoparticles in Melanoma Cells

Angiogenesis plays a key role in cancer progression, including transition to the metastatic phase via reactive oxygen species (ROS)-dependent pathways, among others. Antivascular endothelial growth factor (VEGF) antibodies have been trialed as an anti-angiogenic therapy for cancer but are associated with high cost, limited efficacy, and side effects. Cerium oxide nanoparticles (nanoceria) are promising nanomaterials for biomedical applications due to their ability to modulate intracellular ROS. Nanoceria can be produced by a range of synthesis methods, with chemical precipitation as the most widely explored. It has been reported that chemical precipitation can fine-tune primary particle size where a limited number of synthesis parameters were varied. Here, we explore the effect of temperature, precipitating agent concentration and rate of addition, stirring rate, and surfactant concentration on nanoceria primary particle size using a fractional factorial experimental design approach. We establish a robust synthesis method for faceted nanoceria with primary particle diameters of 5-6 nm. The nanoceria are not cytotoxic to a human melanoma cell line (Mel1007) at doses up to 400 μg/mL and are dose-dependently internalized by the cells. The intracellular ROS level for some cells that internalized the nanoceria is reduced, which correlates with a dose-dependent reduction in angiogenic gene expression including VEGF. These findings contribute to our knowledge of the anti-angiogenic effects of nanoceria and help to develop our understanding of potentially new anti-angiogenic agents for combination cancer therapies.

ROS as Regulators of Cellular Processes in Melanoma

In this review, we examine the multiple roles of ROS in the pathogenesis of melanoma, focusing on signal transduction and regulation of gene expression. In recent years, different studies have analyzed the dual role of ROS in regulating the redox system, with both negative and positive consequences on human health, depending on cell concentration of these agents. High ROS levels can result from an altered balance between oxidant generation and intracellular antioxidant activity and can produce harmful effects. In contrast, low amounts of ROS are considered beneficial, since they trigger signaling pathways involved in physiological activities and programmed cell death, with protective effects against melanoma. Here, we examine these beneficial roles, which could have interesting implications in melanoma treatment.

Regulation of mitochondrial dynamics in skin: role in pathophysiology

Skin is a dynamic interface between the external environment and internal organs. It has high turnover that allows the renewal of dead skin cells, thus maintaining a healthy skin homeostasis. Mitochondria fulfills all the energy needs for these cells. In addition, mitochondria are an active source of free radicals that have been determined as crucially important in skin health and disease. The common notion of limited role of mitochondria as merely the cellular powerhouse has drastically changed. Several extracellular stressors have proved to induce impairment in the dynamic properties of mitochondria such as fusion and fission, which further leads to an activation of selective autophagic response known as mitophagy. Altered mitochondrial dynamics have been lately associated with skin photodamage and cutaneous manifestations of several diseased states, thereby suggesting it to be an effective therapeutic target. This review summarizes the molecular mechanisms involved with impaired mitochondrial dynamics and its potential role in skin health and disease.

Bromodomain-containing protein 4 inhibitor JQ1 promotes melanoma cell apoptosis by regulating mitochondrial dynamics

Although the role of bromodomain-containing protein 4 (BRD4) in ovarian cancer, pancreatic cancer, lymphoma, and many other diseases is well known, its function in cutaneous melanoma is only partially understood. The results of the present study show that the BRD4 inhibitor JQ1 promotes the apoptosis of B16 melanoma cells by altering mitochondrial dynamics, thereby inducing mitochondrial dysfunction and increasing oxidative stress. We found that treatment of B16 cells with different concentrations of JQ1 (125 nmol/L or 250 nmol/L) significantly downregulated the expression of protein subunits involved in mitochondrial respiratory chain complexes I, III, IV, and V, increased reactive oxygen species, induced energy metabolism dysfunction, significantly enhanced apoptosis, and activated the mitochondrial apoptosis pathway. At the same time, JQ1 inhibited the activation of AMP-activated protein kinase, a metabolic energy sensor. In addition, we found that the mRNA and protein levels of mitochondrial dynamin-related protein 1 increased, whereas the levels of mitochondrial fusion protein 1 and optic atrophy protein 1 decreased. Mechanistically, we determined that JQ1 inhibited the expression of c-Myc and altered mitochondrial dynamics, eventually leading to changes in the mitochondrial function, metabolism, and apoptosis of B16 melanoma cells.

The BH3 mimetic (±) gossypol induces ROS-independent apoptosis and mitochondrial dysfunction in human A375 melanoma cells in vitro

A major challenge in current cancer therapy is still the treatment of metastatic melanomas of the skin. BH3 mimetics represent a novel group of substances inducing apoptosis. In this study, we investigated the cytotoxic effect of (±) gossypol (GP), a natural compound from cotton seed, on A375 melanoma cells and the underlying biochemical mechanisms. To prevent undesired side effects due to toxicity on normal (healthy) cells, concentrations only toxic for tumor cells have been elaborated. Viability assays were performed to determine the cytotoxicity of GP in A375 melanoma and normal (healthy) cells. For the majority of experiments, a concentration of 2.5 µM GP was used resulting in a ROS-independent but caspase-dependent cell death of A375 melanoma cells. At this level, GP was non-toxic for normal human epidermal melanocytes. GP has a very short half-life, however, it was demonstrated that only the “parent” compound and not decomposition products are responsible for the cytotoxic effect in A375 melanoma cells. GP significantly decreased mitochondrial membrane potential accompanied by a Drp1-dependent loss of mitochondrial integrity (fragmentation) in tumor cells. Taken together, GP induced a ROS-independent intrinsic apoptosis leading to the conclusion that within a specific concentration range, GP may work as effective anticancer drug without harmful side effects.