RESUMO
Cancer is one of the deadliest diseases worldwide. One of the most commonly applied therapeutic techniques to combat this disease is chemotherapy. Despite its success, the majority of clinically applied chemotherapeutic agents are associated with strong side effects and drug resistance. To overcome this limitation, much research efforts are devoted toward the development of new anticancer agents. Among the most promising class of compounds, Cu(II) complexes have emerged. Despite their strong cytotoxic effect, these agents are typically associated with low water solubility, low stability, and poor tumor selectivity. To overcome these limitations, herein, we report on the encapsulation of a promising Cu(II) terpyridine complex with the Pluronic F-127/Poloxamer-407 polymeric carrier into nanoparticles. Besides overcoming the pharmacological drawbacks, the nanoparticles were able to eradicate human breast adenocarcinoma monolayer cells as well as challenging multicellular tumor spheroids at nanomolar concentrations.
Assuntos
Antineoplásicos , Complexos de Coordenação , Cobre , Nanopartículas , Poloxâmero , Piridinas , Humanos , Cobre/química , Piridinas/química , Antineoplásicos/química , Antineoplásicos/farmacologia , Complexos de Coordenação/química , Nanopartículas/química , Poloxâmero/química , Linhagem Celular Tumoral , Polímeros/química , Portadores de Fármacos/química , Esferoides Celulares/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacosRESUMO
Cancer is one of the deadliest diseases worldwide. Chemotherapy remains one of the most dominant forms for anticancer treatment. Despite their clinical success, the used chemotherapeutic agents are associated with severe side effect and pharmacological limitations. To overcome these drawbacks there is a need for the development of new types of chemotherapeutic agents. Herein, the chemical synthesis and biological evaluation of dinuclear rhenium(I) complexes as potential chemotherapeutic drug candidates are proposed. The metal complexes were found to be internalized by an energy dependent endocytosis pathway, primary accumulating in the mitochondria. The rhenium(I) complexes demonstrated to induce cell death against a variety of cancer cells in the micromolar range through apoptosis. The lead compound showed to eradicate a pancreatic carcinoma multicellular tumor spheroid at micromolar concentrations.
Assuntos
Antineoplásicos , Apoptose , Complexos de Coordenação , Rênio , Rênio/química , Humanos , Antineoplásicos/química , Antineoplásicos/farmacologia , Antineoplásicos/síntese química , Complexos de Coordenação/química , Complexos de Coordenação/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Ensaios de Seleção de Medicamentos Antitumorais , Proliferação de Células/efeitos dos fármacosRESUMO
Despite significant improvements in the treatment of cancerous tumors in the last decades, cancer remains one of the deadliest diseases worldwide. To overcome the shortcomings of currently applied chemotherapeutic treatments, much research efforts have been devoted towards the development of ferroptosis inducing anticancer agents. Ferroptosis is a newly described form of regulated, non-apoptotic cell death that is associated with high potential inside the clinics. Herein, the chemical synthesis and biological evaluation of a Co(III) polypyridine sulfasalazine as a ferroptosis inducer is reported. Upon entering the cancerous cells, the metal complex primarily accumulated in the mitochondria, triggering the production of hydroxy radicals and lipid peroxides, ultimately causing cell death by ferroptosis. The compound demonstrated to eradicate various monolayer cancer cells as well as colon carcinoma multicellular tumor spheroids. To the best of our knowledge this study reports on the first example of a Co(III) complex that is capable of inducing ferroptosis.
RESUMO
Clinical imaging techniques are widely used to detect, locate, and track the growth or shrinkage of cancerous tumors. Although these techniques have shown impressive results, they often come with health risks due to the use of toxic contrast agents or ionizing radiation. To address these limitations, research efforts have been focused on the development of new imaging techniques. Among the emerging medicinal methods, photoacoustic imaging is receiving much attention. This method effectively combines the most important benefits of both ultrasound and fluorescence imaging, while minimizing their respective drawbacks via a light-in and ultrasound-out approach. This review article focuses on the fundamental concept, recent advances, and strategies for novel contrast agents based on molecular metal complexes or metallic nanoparticles for use in photoacoustic imaging.
Assuntos
Complexos de Coordenação , Nanopartículas Metálicas , Nanopartículas , Neoplasias , Técnicas Fotoacústicas , Humanos , Meios de Contraste , Técnicas Fotoacústicas/métodos , Nanopartículas Metálicas/toxicidade , Imagem Óptica/métodos , Neoplasias/diagnóstico por imagemRESUMO
An increasing number of novel Ru(II) polypyridyl complexes have been successfully applied as photosensitizers (PSs) for photodynamic therapy (PDT). Despite recent advances in optimized PSs with refined photophysical properties, the lack of tumoral selectivity is often a major hurdle for their clinical development. Here, classical maleimide and versatile NHS-activated acrylamide strategies were employed to site-selectively conjugate a promising Ru(II) polypyridyl complex to the N-terminally Cys-modified Bombesin (BBN) targeting unit. Surprisingly, the decreased cell uptake of these novel Ru-BBN conjugates in cancer cells did not hamper the high phototoxic activity of the Ru-containing bioconjugates and even decreased the toxicity of the constructs in the absence of light irradiation. Overall, although deceiving in terms of selectivity, our new bioconjugates could still be useful for advanced cancer treatment due to their nontoxicity in the dark.
Assuntos
Antineoplásicos , Complexos de Coordenação , Neoplasias , Fotoquimioterapia , Rutênio , Complexos de Coordenação/farmacologia , Complexos de Coordenação/efeitos da radiação , Rutênio/farmacologia , Bombesina , Fármacos Fotossensibilizantes/farmacologia , Antineoplásicos/farmacologia , Neoplasias/tratamento farmacológicoRESUMO
Maleimide-containing prodrugs can quickly and selectively react with circulating serum albumin following their injection in the bloodstream. The drug-albumin complex then benefits from longer blood circulation times and better tumor accumulation. Herein, we have applied this strategy to a previously reported highly phototoxic Ru polypyridyl complex-based photosensitizer to increase its accumulation at the tumor, reduce off-target cytotoxicity, and therefore improve its pharmacological profile. Specifically, two complexes were synthesized bearing a maleimide group: one complex with the maleimide directly incorporated into the bipyridyl ligand, and the other has a hydrophilic linker between the ligand and the maleimide group. Their interaction with albumin was studied in-depth, revealing their ability to efficiently bind both covalently and noncovalently to the plasma protein. A crucial finding is that the maleimide-functionalized complexes exhibited significantly lower cytotoxicity in noncancerous cells under dark conditions compared to the nonfunctionalized complex, which is a highly desirable property for a photosensitizer. The binding to albumin also led to a decrease in the phototoxicity of the Ru bioconjugates in comparison to the nonfunctionalized complex, probably due to a decreased cellular uptake. Unfortunately, this decrease in phototoxicity was not compensated by a dramatic increase in tumor accumulation, as was demonstrated in a tumor-bearing mouse model using inductively coupled plasma mass spectrometry (ICP-MS) studies. Consequently, this study provides valuable insight into the future design of in situ albumin-binding complexes for photodynamic therapy in order to maximize their effectiveness and realize their full potential.
Assuntos
Antineoplásicos , Complexos de Coordenação , Neoplasias , Fotoquimioterapia , Rutênio , Animais , Camundongos , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/química , Rutênio/farmacologia , Rutênio/química , Ligantes , Albumina Sérica , Maleimidas/farmacologia , Complexos de Coordenação/farmacologia , Complexos de Coordenação/química , Antineoplásicos/químicaRESUMO
Cancer is one of the deadliest diseases worldwide. Recent statistics have shown that metastases and tumor relapse are the leading causes of cancer-associated deaths. While traditional treatments are able to efficiently remove the primary tumor, secondary tumors remain poorly accessible. Capitalizing on this there is an urgent need for novel treatment modalities. Among the most promising approaches, increasing research interest has been devoted to immunogenic cell death inducing agents that are able to trigger localized cell death of the cancer cells as well as induce an immune response inside the whole organism. Preliminary studies have shown that immunogenic cell death inducing compounds could be able to overcome metastatic and relapsing tumors. Herein, the application of metal complexes as immunogenic cell death inducing compounds is systematically reviewed.
Assuntos
Complexos de Coordenação , Neoplasias , Humanos , Complexos de Coordenação/farmacologia , Complexos de Coordenação/uso terapêutico , Morte Celular Imunogênica , Neoplasias/tratamento farmacológico , Morte Celular , ImunoterapiaRESUMO
The development of PtIV prodrugs that are reduced into the therapeutically active PtII species within the tumor microenvironment has received much research interest. In order to provide spatial and temporal control over the treatment, there is a high demand for the development of compounds that could be selectively activated upon irradiation. Despite recent progress, the majority of PtIV complexes are excited with ultraviolet or blue light, limiting the use of such compounds to superficial application. To overcome this limitation, herein, the first example of PtIV prodrug nanoparticles that could be reduced with deeply penetrating ultrasound radiation is reported, enabling the treatment of deep-seated or large tumors. The nanoparticles were found to selectively accumulate inside a mouse colon carcinoma tumor upon intravenous injection and were able to eradicate the tumor upon exposure to ultrasound radiation.
Assuntos
Antineoplásicos , Nanopartículas , Neoplasias , Pró-Fármacos , Animais , Camundongos , Pró-Fármacos/farmacologia , Pró-Fármacos/uso terapêutico , Platina/uso terapêutico , Neoplasias/tratamento farmacológico , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Microambiente TumoralRESUMO
Despite the clinical success of photodynamic therapy (PDT), the application of this medical technique is intrinsically limited by the low oxygen concentrations found in cancer tumors, hampering the production of therapeutically necessary singlet oxygen (1O2). To overcome this limitation, we report on a novel mitochondria-localized iridium(III) endoperoxide prodrug (2-O-IrAn), which, upon two-photon irradiation in NIR, synergistically releases a highly cytotoxic iridium(III) complex (2-IrAn), singlet oxygen, and an alkoxy radical. 2-O-IrAn was found to be highly (photo-)toxic in hypoxic tumor cells and multicellular tumor spheroids (MCTS) in the nanomolar range. To provide cancer selectivity and improve the pharmacological properties of 2-O-IrAn, it was encapsulated into a biotin-functionalized polymer. The generated nanoparticles were found to nearly fully eradicate the tumor inside a mouse model within a single treatment. This study presents, to the best of our knowledge, the first example of an iridium(III)-based endoperoxide prodrug for synergistic photodynamic therapy/photoactivated chemotherapy, opening up new avenues for the treatment of hypoxic tumors.
Assuntos
Neoplasias , Fotoquimioterapia , Pró-Fármacos , Animais , Linhagem Celular Tumoral , Hipóxia/tratamento farmacológico , Irídio/farmacologia , Camundongos , Mitocôndrias , Neoplasias/tratamento farmacológico , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/farmacologia , Pró-Fármacos/farmacologia , Pró-Fármacos/uso terapêutico , Oxigênio Singlete/uso terapêuticoRESUMO
Herein, a new scaffold for anion recognition based on a tripodal tris(pyrrolamide) motif is presented. The receptors were able to bind to a variety of anions with high affinity. Using density functional theory methods, the three-dimensional geometry of the receptor-anion complex was calculated. These calculations show that the receptors bind anions via a preorganized cavity of amide and pyrrole hydrogen bond donor groups. Based on these findings, homochiral tris(pyrrolamide) receptors were prepared, which produced as much as a 1.6-fold greater affinity for (S)-(+)-mandelate over (R)-(-)-mandelate, demonstrating the ability to differentiate between these enantiomeric anions. The interaction of (S)-(+)-mandelate and (R)-(-)-mandelate within the homochiral receptor was examined by solution NMR spectroscopy and density functional theory calculations. These findings indicate that the preorganized positioning of the pyrrole groups and subsequent sterics allows to differentiate between the stereoisomeric anions.
RESUMO
Cancer has emerged over the last decades as one of the deadliest diseases in the world. Among the most commonly used techniques (i.e. surgery, immunotherapy, radiotherapy or chemotherapy), increasing attention has been devoted towards photodynamic therapy. However, the vast majority of clinically applied photosensitizers are not ideal and associated with several limitations including poor aqueous solubility, poor photostability and slow clearance from the body, causing photosensitivity. In an effort to overcome these drawbacks, much attention has been devoted towards the incorporation of a metal ion. Herein, the clinical development of metal-containing compounds including Purlytin® , Lutrin® /Antrin® , Photosens® , TOOKAD® soluble or TLD-1433 is critically reviewed.
Assuntos
FotoquimioterapiaRESUMO
The development of PtIV prodrugs which are selectively reduced within cancerous cells into their PtII therapeutically active species has received increasing attention within the last decade. Despite recent research progress, the majority of investigated compounds are excited using ultraviolet or blue light. As the light penetration depth is low at these wavelengths, the treatment of deep-seated or large tumors is limited. To overcome this limitation, herein, the example of PtIV -functionalized nanoparticles that could be excited within the NIR region at 808â nm is reported. The polymer backbone which can self-assemble into nanoparticles was functionalized with PtIV complexes for chemotherapy, photosensitizers for photodynamic immunotherapy, and nucleus/cancer-targeting peptides. Upon irradiation, the PtIV center is reduced to PtII and the axially coordinated ligands are released, presenting a multimodal treatment. While selectively accumulating in tumorous tissue, the nanoparticles demonstrated the ability to eradicate a triple-negative breast cancer tumor inside a mouse model.
Assuntos
Nanopartículas , Fotoquimioterapia , Pró-Fármacos , Animais , Linhagem Celular Tumoral , Imunoterapia , Camundongos , Nanopartículas/química , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/uso terapêutico , Pró-Fármacos/químicaRESUMO
The clinical application of photodynamic therapy is hindered by the high glutathione concentration, poor cancer-targeting properties, poor drug loading into delivery systems, and an inefficient activation of the cell death machinery in cancer cells. To overcome these limitations, herein, the formulation of a promising IrIII complex into a biodegradable coordination polymer (IrS NPs) is presented. The nanoparticles were found to remain stable under physiological conditions but deplete glutathione and disintegrate into the monomeric metal complexes in the tumor microenvironment, causing an enhanced therapeutic effect. The nanoparticles were found to selectively accumulate in the mitochondria where these trigger cell death by hybrid apoptosis and ferroptosis pathways through the photoinduced production of singlet oxygen and superoxide anion radicals. This study presents the first example of a coordination polymer that can efficiently cause cancer cell death by apoptosis and ferroptosis upon irradiation, providing an innovative approach for cancer therapy.
Assuntos
Complexos de Coordenação , Ferroptose , Fotoquimioterapia , Apoptose , Linhagem Celular Tumoral , Complexos de Coordenação/farmacologia , Complexos de Coordenação/uso terapêutico , Glutationa , Irídio/farmacologia , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/uso terapêutico , Polímeros/farmacologiaRESUMO
The application of G-quadruplex stabilizers presents a promising anticancer strategy. However, the molecular crowding conditions within cells diminish the potency of current G-quadruplex stabilizers. Herein, chiral RuII -PtII dinuclear complexes were developed as highly potent G-quadruplex stabilizers even under challenging molecular crowding conditions. The compounds were encapsulated with biotin-functionalized DNA cages to enhance sub-cellular localization and provide cancer selectivity. The nanoparticles were able to efficiently inhibit the endogenous activities of telomerase in cisplatin-resistant cancer cells and cause cell death by apoptosis. The nanomaterials demonstrated high antitumor activity towards cisplatin-resistant tumor cells as well as tumor-bearing mice. To the best of our knowledge, this study presents the first example of a RuII -PtII dinuclear complex as a G-quadruplex stabilizer with an anti-cancer effect towards drug-resistant tumors inside an animal model.
Assuntos
Antineoplásicos , Complexos de Coordenação , Quadruplex G , Neoplasias , Rutênio , Telomerase , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Cisplatino/metabolismo , Cisplatino/farmacologia , Complexos de Coordenação/metabolismo , Complexos de Coordenação/farmacologia , Complexos de Coordenação/uso terapêutico , DNA , Camundongos , Rutênio/metabolismo , Rutênio/farmacologia , Telomerase/genética , TelômeroRESUMO
The severe acute respiratory syndrome - coronavirus 2 (SARS-CoV-2), the infectious agent responsible for COVID-19 - has caused more than 2.5 million deaths worldwide and triggered a global pandemic. Even with successful vaccines being delivered, there is an urgent need for novel treatments to combat SARS-CoV-2, and other emerging viral diseases. While several organic small molecule drug candidates are in development, some effort has also been devoted towards the application of metal complexes as potential antiviral agents against SARS-CoV-2. Herein, the metal complexes that have been reported to show antiviral activity against SARS-CoV-2 or one of its target proteins are described and their proposed mechanisms of action are discussed.
Assuntos
Antivirais/farmacologia , Complexos de Coordenação/farmacologia , SARS-CoV-2/efeitos dos fármacos , Antivirais/química , Complexos de Coordenação/química , Desenho de FármacosRESUMO
During the last decades, photodynamic therapy (PDT), an approved medical technique, has received increasing attention to treat certain types of cancer. Despite recent improvements, the treatment of large tumors remains a major clinical challenge due to the low ability of the photosensitizer (PS) to penetrate a 3D cellular architecture and the low oxygen concentrations present in the tumor center. To mimic the conditions found in clinical tumors, exceptionally large 3D multicellular tumor spheroids (MCTSs) with a diameter of 800â µm were used in this work to test a series of new RuII polypyridine complexes as one-photon and two-photon PSs. These metal complexes were found to fully penetrate the 3D cellular architecture and to generate singlet oxygen in the hypoxic center upon light irradiation. While having no observed dark toxicity, the lead compound of this study showed an impressive phototoxicity upon clinically relevant one-photon (595â nm) or two-photon (800â nm) excitation with a full eradication of the hypoxic center of the MCTSs. Importantly, this efficacy was also demonstrated on mice bearing an adenocarcinomic human alveolar basal epithelial tumor.
Assuntos
Compostos Organometálicos , Fotoquimioterapia , Fármacos Fotossensibilizantes , Rutênio , Adenocarcinoma Bronquioloalveolar/tratamento farmacológico , Adenocarcinoma Bronquioloalveolar/metabolismo , Animais , Células HeLa , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/metabolismo , Camundongos , Neoplasia de Células Basais/tratamento farmacológico , Neoplasia de Células Basais/metabolismo , Compostos Organometálicos/química , Compostos Organometálicos/farmacologia , Fótons/uso terapêutico , Fármacos Fotossensibilizantes/farmacologia , Piridinas/química , Piridinas/farmacologia , Rutênio/química , Rutênio/farmacologia , Oxigênio Singlete/metabolismo , Esferoides Celulares , Hipóxia Tumoral , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The global spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has called for an urgent need for dedicated antiviral therapeutics. Metal complexes are commonly underrepresented in compound libraries that are used for screening in drug discovery campaigns, however, there is growing evidence for their role in medicinal chemistry. Based on previous results, we have selected more than 100â structurally diverse metal complexes for profiling as inhibitors of two relevant SARS-CoV-2 replication mechanisms, namely the interaction of the spike (S) protein with the ACE2 receptor and the papain-like protease PLpro . In addition to many well-established types of mononuclear experimental metallodrugs, the pool of compounds tested was extended to approved metal-based therapeutics such as silver sulfadiazine and thiomersal, as well as polyoxometalates (POMs). Among the mononuclear metal complexes, only a small number of active inhibitors of the S/ACE2 interaction was identified, with titanocene dichloride as the only strong inhibitor. However, among the gold and silver containing complexes many turned out to be very potent inhibitors of PLpro activity. Highly promising activity against both targets was noted for many POMs. Selected complexes were evaluated in antiviral SARS-CoV-2 assays confirming activity for gold complexes with N-heterocyclic carbene (NHC) or dithiocarbamato ligands, a silver NHC complex, titanocene dichloride as well as a POM compound. These studies might provide starting points for the design of metal-based SARS-CoV-2 antiviral agents.
Assuntos
Antivirais/farmacologia , Proteases Semelhantes à Papaína de Coronavírus/antagonistas & inibidores , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/antagonistas & inibidores , Enzima de Conversão de Angiotensina 2 , SARS-CoV-2/efeitos dos fármacosRESUMO
Bioisosteres are a useful approach to address pharmacokinetic liabilities and improve drug-like properties. Specific to developing metalloenzyme inhibitors, metal-binding pharmacophores (MBPs) have been combined with bioisosteres, to produce metal-binding isosteres (MBIs) as alternative scaffolds for use in fragment-based drug discovery (FBDD). Picolinic acid MBIs have been reported and evaluated for their metal-binding ability, pharmacokinetic properties, and enzyme inhibitory activity. However, their structural, electronic, and spectroscopic properties with metal ions other than Zn(II) have not been reported, which might reveal similarities and differences between MBIs and the parent MBPs. To this end, [M(TPA)(MBI)]+ (M = Ni(II) and Co(II), TPA = tris(2-pyridylmethyl)amine) is presented as a bioinorganic model system for investigating picolinic acid, four heterocyclic MBIs, and 2,2'-bipyridine. These complexes were characterized by X-ray crystallography as well as NMR, IR, and UV-vis spectroscopies, and their magnetic moments were accessed. In addition, [(TpPh,Me)Co(MBI)] (TpPh,Me = hydrotris(3,5-phenylmethylpyrazolyl)borate) was used as a second model compound, and the limitations and attributes of the two model systems are discussed. These results demonstrate that bioinorganic model complexes are versatile tools for metalloenzyme inhibitor design and can provide insights into the broader use of MBIs.
RESUMO
Since its outbreak, the severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) has impacted the quality of life and cost hundreds-of-thousands of lives worldwide. Based on its global spread and mortality, there is an urgent need for novel treatments which can combat this disease. To date, the 3-chymotrypsin-like protease (3CLpro ), which is also known as the main protease, is considered among the most important pharmacological targets. The vast majority of investigated 3CLpro inhibitors are organic, non-covalent binders. Herein, the use of inorganic, coordinate covalent binders is proposed that can attenuate the activity of the protease. ReI tricarbonyl complexes were identified that demonstrate coordinate covalent enzymatic inhibition of 3CLpro . Preliminary studies indicate the selective inhibition of 3CLpro over several human proteases. This study presents the first example of metal complexes as inhibitors for the 3CLpro cysteine protease.
Assuntos
Tratamento Farmacológico da COVID-19 , Complexos de Coordenação/farmacologia , Proteases 3C de Coronavírus/antagonistas & inibidores , Inibidores de Proteases/farmacologia , Rênio/farmacologia , SARS-CoV-2/enzimologia , Antivirais/química , Antivirais/farmacologia , Complexos de Coordenação/química , Proteases 3C de Coronavírus/metabolismo , Descoberta de Drogas , Humanos , Modelos Moleculares , Inibidores de Proteases/química , Rênio/química , SARS-CoV-2/efeitos dos fármacosRESUMO
The utilization of photodynamic therapy (PDT) for the treatment of various types of cancer has gained increasing attention over the last decades. Despite the clinical success of approved photosensitizers (PSs), their application is sometimes limited due to poor water solubility, aggregation, photodegradation, and slow clearance from the body. To overcome these drawbacks, research efforts are devoted toward the development of metal complexes and especially Ru(II) polypyridine complexes based on their attractive photophysical and biological properties. Despite the recent research developments, the vast majority of complexes utilize blue or UV-A light to obtain a PDT effect, limiting the penetration depth inside tissues and, therefore, the possibility to treat deep-seated or large tumors. To circumvent these drawbacks, we present the first example of a DFT guided search for efficient PDT PSs with a substantial spectral red shift toward the biological spectral window. Thanks to this design, we have unveiled a Ru(II) polypyridine complex that causes phototoxicity in the very low micromolar to nanomolar range at clinically relevant 595 nm, in monolayer cells as well as in 3D multicellular tumor spheroids.