IR780-loaded TPGS-TOS micelles for breast cancer photodynamic therapy

Micelle-encapsulated IR783 for enhanced photothermal therapy in mouse breast cancer

BACKGROUND

Photothermal therapy, an emerging cancer treatment, selectively eliminates lesions using photothermal compounds that convert light into heat. IR783, a near-infrared fluorescent heptamethine cyanine dye, has been used to achieve selective hyperthermic effects in target tissues via near-infrared irradiation. To implement IR783 as a photothermal agent, IR783 biodistribution must be calibrated to achieve a constant and uniform concentration in target cells. Accordingly, we developed micelle-encapsulated IR783 (IR783 micelles) and evaluated their effectiveness as photothermal drugs.

METHODS

In vitro, the photothermic effects of free IR783 and IR783 micelle solutions induced by near-infrared light irradiation were analyzed. Additionally, we investigated the mechanism of cell death mediated by photothermal therapy using free IR783 and IR783 micelles in mouse breast cancer (EMT6) cells. In vivo, the efficacy of photothermal therapy with both free IR783 and IR783 micelles was examined in EMT6-bearing mice.

RESULTS

In vitro, the temperature of free and micelle-encapsulated IR783 solutions increased after near-infrared irradiation. Near-infrared irradiation with free IR783 and IR783 micelles induced cytotoxicity in cancer cells by generating heat. In vivo, IR783 micelles elicited more preferential tumor tissue uptake and enhanced the antitumor effects of photothermal therapy at a lower light dose relative to free IR783.

CONCLUSIONS

Overall, these results suggest that IR783 micelles could accumulate in mouse breast cancer tissues and exhibit enhanced antitumor effects when used as a photothermal therapy, with superior effects obtained at 2.1 W/cm2 (252 J/cm2) compared with that of free IR783.

Investigating Effects of IR-780 in Animal Models of B16-F10 Melanoma: New Approach in Lung Metastasis

IR-780 is a fluorescent marker, photostable and non-toxic, and is widely used in tumor targeting; however, studies on the impact of IR-780 in animal models of B16-F10 melanoma are scarce in the literature. Therefore, this study aims to analyze behavior of this marker in melanoma cells using in vitro and in vivo analyses with fluorescence microscopy to conduct an analysis of cell culture, and an in vivo imaging system for an analysis of cell culture, tumor targeting on animals, and organ examination. In vitro analysis showed that B16-F10 cells at a concentration of 2 × 105 cells.plate-1 allowed a better visualization using 20 μM of IR-780. Furthermore, the location of IR-780 accumulation was confirmed by its fluorescence microscopy. Through in vivo studies, fluorescence was not observed in subcutaneous nodules, and it was found that animals that received intraperitoneal injection of B16-F10 cells presented ascites and did not absorb IR-780. Additionally, animals exhibiting lung metastasis showed fluorescence in ex vivo lung images. Therefore, use of the IR-780 marker for evaluating the progression of tumor growth did not demonstrate efficiency; however, it was effective in diagnosing pulmonary metastatic tumors. Although this marker presented limitations, results of evaluating pulmonary involvement through ex vivo fluorescence imaging were determined based on intensity of fluorescence.

Simple preparation of POxylated nanomaterials for cancer chemo-PDT/PTT

Near infrared (NIR) light-responsive nanomaterials hold potential to mediate combinatorial therapies targeting several cancer hallmarks. When irradiated, these nanomaterials produce reactive oxygen species (photodynamic therapy) and/or a temperature increase (photothermal therapy). These events can damage cancer cells and trigger the release of drugs from the nanomaterials' core. However, engineering nanomaterials for cancer chemo-photodynamic/photothermal therapy is a complex process. First, nanomaterials with photothermal capacity are synthesized, being then loaded with photosensitizers plus chemotherapeutics, and, finally functionalized with polymers for achieving suitable biological properties. To overcome this limitation, in this work, a novel straightforward approach to attain NIR light-responsive nanosystems for cancer chemo-photodynamic/photothermal therapy was established. Such was accomplished by synthesizing poly(2-ethyl-2-oxazoline)-IR780 amphiphilic conjugates, which can be assembled into nanoparticles with photodynamic/photothermal capabilities that simultaneously encapsulate Doxorubicin (DOX/PEtOx-IR NPs). The DOX/PEtOx-IR NPs presented a suitable size and surface charge for cancer-related applications. When irradiated with NIR light, the DOX/PEtOx-IR NPs produced singlet oxygen as well as a smaller thermic effect that boosted the release of DOX by 1.7-times. In the in vitro studies, the combination of DOX/PEtOx-IR NPs and NIR light could completely ablate breast cancer cells (viability ≈ 4 %), demonstrating the enhanced outcome arising from the nanomaterials' chemo-photodynamic/photothermal therapy.

Synergistic Release of Photothermal Molecules from Nanocarriers Induced by Light and Hyperthermia Benefits Efficient Anticancer Phototherapy

Recently, nanoformulations have been widely applied in the delivery of organic photothermal agents (OPTAs) for cancer therapy to prolong blood circulation or improve tumor-targeting capacity. However, the systematic evaluations of their effects on the photothermal behavior of OPTAs are limited, especially for different types of nanoparticle systems. Herein, we prepared two kinds of nanoparticles (BSA and PEG nanoparticles (NPs)) to load an OPTA, a cyanine photosensitizer (IR780-O-TPE), and investigated their photothermal response, organelle targeting, and in vivo therapeutic efficacy. Due to different assembly forms, the two NPs showed distinct morphological changes after exposure to laser or hyperthermia. Under laser irradiation at 808 nm, BSA NPs could release IR780-O-TPE more efficiently than PEG NPs. We speculate that this phenomenon is probably caused by dual-responsive release of IR780-O-TPE from BSA NPs against light and hyperthermia. Moreover, IR780-O-TPE/BSA NPs were highly mitochondria-targeting and therefore displayed significant inhibition of cell viability. In contrast, IR780-O-TPE/PEG NPs were "shell-core" nanostructures and more stable under laser stimulation. As a consequence, the mitochondria-targeting and anticancer photothermal therapy by IR780-O-TPE/PEG NPs was less obvious. This study revealed the significance of nanocarrier design for OPTA delivery and demonstrated that BSA NPs could release IR780-O-TPE more effectively for efficient photothermal therapy. We also believe that the dual-responsive release of OPTAs from NPs can provide an effective strategy to promote anticancer photothermal treatment.

Engineered upconversion nanocarriers for synergistic breast cancer imaging and therapy: Current state of art

Breast cancer is the most common type of cancer in women and is the second leading cause of cancer-related deaths worldwide. Early diagnosis and effective therapeutic interventions are critical determinants that can improve survival and quality of life in breast cancer patients. Nanotheranostics are emerging interventions that offer the dual benefit of in vivo diagnosis and therapeutics through a single nano-sized carrier. Rare earth metal-doped upconversion nanoparticles (UCNPs) with their ability to convert near-infrared light to visible light or UV light in vivo settings have gained special attraction due to their unique luminescence and tumor-targeting properties. In this review, we have discussed applications of UCNPs in drug and gene delivery, photothermal therapy (PTT), photodynamic therapy (PDT) and tumor targeting in breast cancer. Further, present challenges and future opportunities for UCNPs in breast cancer treatment have also been mentioned.

Redox homeostasis modulation using theranostic AIE nanoparticles results in positive-feedback drug accumulation and enhanced drug penetration to combat drug-resistant cancer

Drug-resistant cancers usually have multiple barriers to compromise the effect of therapies, of which multidrug-resistance (MDR) phenotype as the intracellular barrier and dense tumor matrix as the extracellular barrier, significantly contribute to the poor anticancer performance of current drug delivery systems (DDS). Here in this study, we fabricated a novel aggregation-induced emission (AIE)-active polymer capable of self-assembling into ultrasmall nanoparticles (∼20 ​nm) with D-alpha Tocopheryl Polyethylene Glycol Succinate (TPGS), for dual-encapsulating of doxorubicin (Dox) and sulforaphane (SFN) (AT/Dox/SFN). It revealed that redox homeostasis modulation of MDR cells (MCF-7/Adr) using AT/Dox/SFN can trigger mitochondria damage and ATP deficiency, which reverse the MDR phenotype of MCF-7/Adr cells to afford enhanced cellular uptake of both drug and DDS in a positive-feedback manner. The enhanced cellular drug accumulation further initiates the “neighboring effect” for improved drug penetration. Using this strategy, the growth of in vivo MCF-7/Adr tumors can be effectively inhibited at a low dosage (1/5) of doxorubicin (Dox) as compared to free Dox. In summary, we offer a new approach to overcome both the intracellular and extracellular barriers of drug-resistant cancers and elucidate the potential action mechanisms, which are beneficial for better cancer management.

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Redox homeostasis modulation in MDR cancer cell results in positive-feedback drug accumulation and enhanced drug penetration.

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Mitochondria damage and neighboring effect is responsible for MDR reversal and enhanced drug penetration, respectively.

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AT/Dox/SFN effectively inhibits ​in vivo ​MCF-7/Adr tumors at a low dosage (1/5) of doxorubicin (Dox) as compared to free Dox.

Poly(2-ethyl-2-oxazoline)-IR780 conjugate nanoparticles for breast cancer phototherapy

Aims: To address the limitations of IR780 by preparing hydrophilic polymer-IR780 conjugates and to employ these conjugates in the assembly of nanoparticles (NPs) intended for cancer photothermal therapy. Materials & methods: The cyclohexenyl ring of IR780 was conjugated for the first time with thiol-terminated poly(2-ethyl-2-oxazoline) (PEtOx). This novel poly(2-ethyl-2-oxazoline)-IR780 (PEtOx-IR) conjugate was combined with D-α-tocopheryl succinate (TOS), leading to the assembly of mixed NPs (PEtOx-IR/TOS NPs). Results: PEtOx-IR/TOS NPs displayed optimal colloidal stability as well as cytocompatibility in healthy cells at doses within the therapeutic range. In turn, the combination of PEtOx-IR/TOS NPs and near-infrared light reduced heterotypic breast cancer spheroid viability to just 15%. Conclusion: PEtOx-IR/TOS NPs are promising agents for breast cancer photothermal therapy.

Natural and Synthetic Micelles for Delivery of Small Molecule Drugs, Imaging Agents and Nucleic Acids

The poor solubility, lack of targetability, quick renal clearance, and degradability of many therapeutic and imaging agents strongly limit their applications inside the human body. Amphiphilic copolymers having self-assembling properties can form core-shell structures called micelles, a promising nanocarrier for hydrophobic drugs, plasmid DNA, oligonucleotides, small interfering RNAs (siRNAs) and imaging agents. Fabrication of micelles loaded with different pharmaceutical agents provides numerous advantages including therapeutic efficacy, diagnostic sensitivity, and controlled release to the desired tissues. Moreover, due to their smaller particle size (10-100 nm) and modified surfaces with different functional groups (such as ligands) help them to accumulate easily in the target location, enhancing cellular uptake and reducing unwanted side effects. Furthermore, the release of the encapsulated agents may also be triggered from stimuli-sensitive micelles at different physiological conditions or by an external stimulus. In this review article, we discuss the recent advancement in formulating and targeting different natural and synthetic micelles including block copolymer micelles, cationic micelles, and dendrimers-, polysaccharide- and protein-based micelles for the delivery of different therapeutic and diagnostic agents. Finally, their applications, outcomes, and future perspectives have been summarized.

Hyaluronic acid carrier-based photodynamic therapy for head and neck squamous cell carcinoma

PURPOSE

Conventional photosensitizers for photodynamic therapy (PDT) typically have wide tissue distribution and poor water solubility. A hyaluronic acid (HA) polymeric nanoparticle with specific lymphatic uptake and highly water solubility was developed to deliver pyropheophorbide-a (PPa) for locally advanced head and neck squamous cell carcinoma (HNSCC) treatment.

METHODS AND RESULTS

PPa was chemically conjugated to the HA polymeric nanoparticle via an adipic acid dihydrazide (ADH) linker. The conjugates were injected subcutaneously in a region near the tumor. Near-infrared (NIR) imaging was used to monitor distribution, and diode laser was used to activate PPa. The singlet oxygen generation efficiency of PPa was not affected by conjugation to HA nanoparticles at a PPa loading degree of 1.89 w.t.%. HA-ADH-PPa inhibited human HNSCC MDA-1986 cell growth only when photo-irradiation was applied. After HA-ADH-PPa treatment and radiation, NU/NU mice bearing human HNSCC MDA-1986 tumors showed reduced tumor growth and significantly enhanced survival time compared with an untreated group (p < 0.05).

CONCLUSIONS

These results demonstrate that HA-ADH-PPa could be useful for in vivo locoregional photodynamic therapy of HNSCC.

A hypoxia-responsive supramolecular formulation for imaging-guided photothermal therapy

Photothermal agents (PTAs) based on organic small-molecule dyes emerge as promising theranostic strategy in imaging and photothermal therapy (PTT). However, hydrophobicity, photodegradation, and low signal-to-noise ratio impede their transformation from bench to bedside. In this study, a novel supramolecular PTT formulation by a stimuli-responsive macrocyclic host is prepared to overcome these obstacles of organic small-molecule PTAs. Methods: Sulfonated azocalix[4]arene (SAC4A) was synthesized as a hypoxia-responsive macrocyclic host. Taking IR780 as an example, the supramolecular nanoformulation IR780@SAC4A was constructed by grinding method, and its solubility, photostability, and photothermal conversion were evaluated. The hypoxia tumor-selective imaging and supramolecular PTT of IR780@SAC4A were further evaluated in vitro and in vivo. Results: IR780@SAC4A is capable of enhancing the solubility, photostability, and photothermal conversion of IR780 significantly, which achieve this supramolecular formulation with good imaging-guided PTT efficacy in vitro and in vivo. Conclusions: This study demonstrates that the supramolecular PTT strategy is a promising cancer theranostic method. Moreover, this supramolecular approach is applicative to construct kinds of supramolecular PTAs, opening a general avenue for extending smart PTT formulations.

Design and construction of IR780- and EGCG-based and mitochondrial targeting nanoparticles and their application in tumor chemo-phototherapy

An integration combination of phototherapy and chemotherapy to treat carcinoma, solving the inner limitation of individual-modal chemical agent-based therapy or phototherapy, emerges to be a strategy with high prospects for achieving synergistic curative effects. The dye IR780-iodide (IR780) close to infrared radiation is a phototherapy agent with high prospects. However, it is limited in its clinical applications due to poor solubility in water. While epigallocatechin-3-gallate (EGCG), naturally resourced green tea polyphenol, has been extensively proven with intrinsic antitumor activity, but it is largely restricted by its low bioavailability in vivo. Hence, novel multiple-function nanoparticles comprising hyaluronic acid (HA) and IR780 were proposed to deliver EGCG, defined as EGCG@THSI nano-scale particles (EGCG@THSI NPs), thereby rapidly solving limitations of EGCG and IR780. Amphiphilic nano-scale carrier was prepared by triphenylphosphine (TPP), hyaluronic acid (HA), cystamine, and IR780, termed as TPP-HA-SS-IR780, and EGCG was loaded into the amphiphilic copolymer by self-assembly. TPP-HA-SS-IR780 endowed the as-synthesized EGCG@THSI NPs with excellent TPP-mediated mitochondrial-targeted and glutathione-triggered rapid drug release properties. As impacted by the integration of phototherapy and chemotherapy, the EGCG@THSI NPs under NIR laser irradiation showed a prominent anti-tumor effect. Taken together, this study presented a multiple-function nano-scale carrier platform with high prospects in improving the therapeutic efficacy of anti-carcinoma drugs.

Photodynamic therapy with the dual-mode association of IR780 to PEG-PLA nanocapsules and the effects on human breast cancer cells

IR780 is a near-infrared fluorescent dye, which can be applied as a photosensitizer in photodynamic (PDT) and photothermal (PTT) therapies and as a biodistribution tracer in imaging techniques. We investigated the growth and migration inhibition and mechanism of death of breast tumor cells, MCF-7 and MDA-MB-231, exposed to polymeric nanocapsules (NC) comprising IR780 covalently linked to the biodegradable polymer PLA (IR-PLA) and IR780 physically encapsulated (IR780-NC) in vitro. Both types of NC had mean diameters around 120 nm and zeta potentials around -40 mV. IR-PLA-NC was less cytotoxic than IR780 NC to a non-tumorigenic mammary epithelial cell line, MCF-10A, which is an important aspect of selectivity. Free-IR780 was more cytotoxic than IR-PLA-NC for MCF-7 and MDA-MB-231 cells after illumination with a 808 nm laser. IR-PLA NC was effective to inhibit colony formation (50%) and migration (30-40%) for both cancer cell lines. MDA-MB-231 cells were less sensitive to all IR780 formulations compared to MCF-7 cells. Cell uptake was higher with IR-PLA-NC than with IR780-NC and free-IR780 in both cancer cell lines (p < 0.05). NC uptake was higher in MCF-7 than in MDA-MB-231 cells. IR-PLA-NC induced a higher percentage of apoptosis upon illumination in MDA-MB-231 than in MCF-7 cells. The necrosis mechanism of death predominated in treatments with free-IR780 and with encapsulated IR780 NC, suggestive of damages at the plasma membrane. IR780 conjugated with PLA increased the apoptotic pathway and demonstrated potential as a multifunctional theranostic agent for breast cancer treatment with increased cellular uptake, photodynamic activity and more reliable tracking in cell-image studies.

Effects of Human Serum Albumin on the Fluorescence Intensity and Tumor Imaging Properties of IR-780 Dye

IR-780 is a lipophilic dye with excellent optical and tumor imaging properties for early tumor diagnostics. Although the mechanism of tumor targeting has not been fully identified, the view that serum albumin plays an important role in tumor accumulation has been recognized. Here, the mechanism of the interaction between IR-780 and HSA was studied to explore the effect of albumin on its tumor targeting properties. Data demonstrate that IR-780 can be tightly adsorbed by HSA at a ratio of 1:1 to form a noncovalent complex, which exhibits significant improvement in the near-infrared fluorescence imaging and tumor diagnosis capacity. During this process, the endogenous fluorescence and esterase activity of HSA are both partially inhibited by IR-780, and the α-helical content of HSA slightly increases. Molecular docking simulation displays that the binding site of IR-780 on HSA is between subdomains IIA and IIB. These results indicate that HSA is an important factor to mediate the optical performance of IR-780, giving it higher tumor diagnosis capability.

Recent Advances in Diagnostic and Therapeutic Approaches for Breast Cancer: A Comprehensive Review

A silent monster, breast cancer, is a challenging medical task for researchers. Breast cancer is a leading cause of death in women with respect to other cancers. A case of breast cancer is diagnosed among women every 19 seconds, and every 74 seconds, a woman dies of breast cancer somewhere in the world. Several risk factors, such as genetic and environmental factors, favor breast cancer development. This review tends to provide deep insights regarding the genetics of breast cancer along with multiple diagnostic and therapeutic approaches as problem-solving negotiators to prevent the progression of breast cancer. This assembled data mainly aims to discuss omics-based approaches to provide enthralling diagnostic biomarkers and emerging novel therapies to combat breast cancer. This review article intends to pave a new path for the discovery of effective treatment options.

MitoTracker Deep Red (MTDR) Is a Metabolic Inhibitor for Targeting Mitochondria and Eradicating Cancer Stem Cells (CSCs), With Anti-Tumor and Anti-Metastatic Activity In Vivo

MitoTracker Deep Red (MTDR) is a relatively non-toxic, carbocyanine-based, far-red, fluorescent probe that is routinely used to chemically mark and visualize mitochondria in living cells. Previously, we used MTDR at low nano-molar concentrations to stain and metabolically fractionate breast cancer cells into Mito-high and Mito-low cell sub-populations, by flow-cytometry. Functionally, the Mito-high cell population was specifically enriched in cancer stem cell (CSC) activity, i) showing increased levels of ESA cell surface expression and ALDH activity, ii) elevated 3D anchorage-independent growth, iii) larger overall cell size (>12-μm) and iv) Paclitaxel-resistance. The Mito-high cell population also showed enhanced tumor-initiating activity, in an in vivo preclinical animal model. Here, we explored the hypothesis that higher nano-molar concentrations of MTDR could also be used to therapeutically target and eradicate CSCs. For this purpose, we employed an ER(+) cell line (MCF7) and two triple negative cell lines (MDA-MB-231 and MDA-MB-468), as model systems. Remarkably, MTDR inhibited 3D mammosphere formation in MCF7 and MDA-MB-468 cells, with an IC-50 between 50 to 100 nM; similar results were obtained in MDA-MB-231 cells. In addition, we now show that MTDR exhibited near complete inhibition of mitochondrial oxygen consumption rates (OCR) and ATP production, in all three breast cancer cell lines tested, at a level of 500 nM. However, basal glycolytic rates in MCF7 and MDA-MB-468 cells remained unaffected at levels of MTDR of up to 1 μM. We conclude that MTDR can be used to specifically target and eradicate CSCs, by selectively interfering with mitochondrial metabolism, by employing nano-molar concentrations of this chemical entity. In further support of this notion, MTDR significantly inhibited tumor growth and prevented metastasis in vivo, in a xenograft model employing MDA-MB-231 cells, with little or no toxicity observed. In contrast, Abemaciclib, an FDA-approved CDK4/6 inhibitor, failed to inhibit metastasis. Therefore, in the future, MTDR could be modified and optimized via medicinal chemistry, to further increase its potency and efficacy, for its ultimate clinical use in the metabolic targeting of CSCs for their eradication.

AT, Chuang CC, Chen JP. Liposomal IR-780 as a Highly Stable Nanotheranostic Agent for Improved Photothermal/Photodynamic Therapy of Brain Tumors by Convection-Enhanced Delivery

As a hydrophobic photosensitizer, IR-780 suffers from poor water solubility and low photostability under near infrared (NIR) light, which severely limits its use during successive NIR laser-assisted photothermal/photodynamic therapy (PTT/PDT). To solve this problem, we fabricate cationic IR-780-loaded liposomes (ILs) by entrapping IR-780 within the lipid bilayer of liposomes. We demonstrate enhanced photostability of IR-780 in ILs with well-preserved photothermal response after three repeated NIR laser exposures, in contrast to the rapid decomposition of free IR-780. The cationic nature of ILs promotes fast endocytosis of liposomal IR-780 by U87MG human glioblastoma cells within 30 min. For PTT/PDT in vitro, ILs treatment plus NIR laser irradiation leads to overexpression of heat shock protein 70 and generation of intracellular reactive oxygen species by U87MG cells, resulting in enhanced cytotoxicity and higher cell apoptosis rate. Using intracranial glioma xenograft in nude mice and administration of ILs by convection enhanced delivery (CED) to overcome blood-brain barrier, liposomal IR-780 could be specifically delivered to the brain tumor, as demonstrated from fluorescence imaging. By providing a highly stable liposomal IR-780, ILs significantly improved anti-cancer efficacy in glioma treatment, as revealed from various diagnostic imaging tools and histological examination. Overall, CED of ILs plus successive laser-assisted PTT/PDT may be an alternative approach for treating brain tumor, which can retard glioma growth and prolong animal survival times from orthotopic brain tumor models.

IR780-based nanomaterials for cancer imaging and therapy

IR780, a small molecule with a strong optical property and excellent photoconversion efficiency following near infrared (NIR) irradiation, has attracted increasing attention in the field of cancer treatment and imaging. This review is focused on different IR780-based nanoplatforms and the application of IR780-based nanomaterials for cancer bioimaging and therapy. Thus, this review summarizes the overall aspects of IR780-based nanomaterials that positively impact cancer biomedical applications.

Self-assembled multifunctional polymeric micelles for tumor-specific bioimaging and synergistic chemo-phototherapy of cancer

Integration of multiple therapies into one nanoplatform holds great promise to overcome the shortcomings of traditional single-modal therapy and achieve favorable antitumor efficacy. Herein, we constructed a dual receptor-targeting nanomicelle system with GSH-responsive drug release for precise fluorescence imaging and superior chemo-phototherapy of cancer. The synthetic amphiphilic hyaluronic acid derivative (FHSV) could self-assemble into nanomicelles in aqueous media. Then, paclitaxel (PTX) and photosensitizer IR780 iodide (IR780) were co-loaded into the micelles by a simple dialysis method. The resulting IR780/PTX/FHSV micelles with a particle size of 150.2 ± 6.9 nm exhibited excellent stability, GSH-responsive drug release and good photothermal/photodynamic efficacy. Once accumulated at the tumor sites, IR780/PTX/FHSV micelles efficiently entered tumor cells through receptor-mediated endocytosis and then rapidly release PTX and IR780 under GSH-rich tumor microenvironment. Upon NIR laser irradiation, IR780 produced local hyperthermia and sufficient reactive oxygen species to promote tumor cells apoptosis and necrosis. The results of in vitro and in vivo experiments consistently demonstrated that compared with single chemotherapy and phototherapy, the chemo-phototherapy could more efficiently kill tumor cells by synergistic antitumor effect. Therefore, our study provides a novel and efficient approach for multimodal treatment of malignant tumor.

Injectable in situ forming hydrogels incorporating dual-nanoparticles for chemo-photothermal therapy of breast cancer cells

Chemo-photothermal therapy (chemo-PTT) mediated by nanomaterials holds a great potential for cancer treatment. However, the tumor uptake of the systemically administered nanomaterials was recently found to be below 1%. To address this limitation, the development of injectable tridimensional polymeric matrices capable of delivering nanomaterials directly into the tumor site appears to be a promising approach. In this work, an injectable in situ forming ionotropically crosslinked chitosan-based hydrogel co-incorporating IR780 loaded nanoparticles (IR/BPN) and Doxorubicin (DOX) loaded nanoparticles (DOX/TPN) was developed for application in breast cancer chemo-PTT. The produced hydrogels (IR/BPN@Gel and IR/BPN+DOX/TPN@Gel) displayed suitable physicochemical properties and produced a temperature increase of about 9.1 °C upon exposure to Near Infrared (NIR) light. As importantly, the NIR-light exposure also increased the release of DOX from the hydrogel by 1.7-times. In the in vitro studies, the combination of IR/BPN@Gel with NIR light (photothermal therapy) led to a reduction in the viability of breast cancer cells to 35%. On the other hand, the non-irradiated IR/BPN+DOX/TPN@Gel (chemotherapy) only diminished cancer cells' viability to 85%. In contrast, the combined action of IR/BPN+DOX/TPN@Gel and NIR light reduced cancer cells' viability to about 9%, demonstrating its potential for breast cancer chemo-PTT.

Assessing the Combinatorial Chemo-Photothermal Therapy Mediated by Sulfobetaine Methacrylate-Functionalized Nanoparticles in 2D and 3D In Vitro Cancer Models

Combinatorial cancer therapies mediated by nanomaterials can potentially overcome the limitations of conventional treatments. These therapies are generally investigated using 2D in vitro cancer models, leading to an inaccurate screening. Recently, 3D in vitro spheroids have emerged in the preclinical testing stage of nanomedicines due to their ability to mimic key features of the in vivo solid tumors. Investigate the chemo-photothermal therapy mediated by Doxorubicin and IR780 loaded sulfobetaine methacrylate functionalized nanoparticles, for the first time, using monolayers of cancer cells and spheroids. In the 2D cancer models, the nanomaterials' mediated photothermal therapy, chemotherapy, and chemo-photothermal therapy reduced cancer cells' viability to about 58%, 29%, and 1%, respectively. Interestingly, when the nanomaterials' mediated photothermal therapy is tested on 3D spheroids, no cytotoxic effect is noticed. In contrast, the nanostructures' induced chemotherapy decreased spheroids' viability to 42%. On the other hand, nanomaterials' mediated chemo-photothermal therapy diminished spheroids' viability to 16%, being the most promising therapeutic modality. These results demonstrate the importance of using 3D spheroids during the in vitro screening of single/combinatorial therapies mediated by nanomaterials.

pH Reversibly Switchable Nanocapsule for Bacteria-Targeting Near-Infrared Fluorescence Imaging-Guided Precision Photodynamic Sterilization

Photodynamic sterilization is the most promising method to combat bacterial infection, especially multidrug-resistant bacterial infection. However, the absorption of conventional photosensitizers is mostly located in the UV-vis region, leading to limited penetration depth and poor therapeutic efficacy for deep-tissue bacterial infection. Besides, most of the photosensitizers are always in the activated state and lack bacteria-targeting ability, which inevitably causes severe nonspecific damage to normal tissues. Here, we show the design of a pH reversibly switchable near-infrared photosensitizer-based nanocapsule for precision bacteria-targeting fluorescence imaging-guided photodynamic sterilization. pH reversibly activatable asymmetric cyanine was synthesized as a bacteria-specific imaging unit and smart photosensitizer to realize precision imaging-guided targeting sterilization without side effects. An allicin mimic was introduced into the smart photosensitizer as the auxiliary bactericidal group to further enhance antibacterial efficiency. Meanwhile, amphipathic functionalized polyethylene glycol was employed to fabricate the nanocapsule by self-assembly to endow the charge-reversed intelligent targeting ability and prolong blood circulation. The developed switchable nanocapsule not only enables precision bacterial infection-targeted imaging without background fluorescence interference but also gives an efficient bactericidal effect with excellent specificity and negligible side effects, holding great potential for practical application.

The importance of spheroids in analyzing nanomedicine efficacy

The use of nanomedicines for cancer treatment holds a great potential due to their improved efficacy and safety. During the nanomedicine preclinical in vitro evaluation stage, these are mainly tested on cell culture monolayers. However, these 2D models are an unrealistic representation of the in vivo tumors, leading to an inaccurate screening of the candidate formulations. To address this problem, spheroids are emerging as an additional tool to validate the efficacy of new therapeutics due to the ability of these 3D in vitro cancer models to mimic the key features displayed by in vivo solid tumors. In this review, the application of spheroids for the evaluation of nanomedicines' physicochemical properties and therapeutic efficacy is discussed.

IR780 loaded sulfobetaine methacrylate-functionalized albumin nanoparticles aimed for enhanced breast cancer phototherapy

New insights about nanomaterials' biodistribution revealed their ability to achieve tumor accumulation by taking advantage from the dynamic vents occurring in tumor's vasculature. This paradigm-shift emphasizes the importance of extending nanomaterials' blood circulation time to enhance their tumor uptake. The classic strategy to improve nanomaterials' stability during circulation relies on their functionalization with poly(ethylene glycol). However, recent reports have been showing that PEGylated nanomaterials can suffer from the accelerated blood clearance phenomenon, emphasizing the importance of developing novel coatings for functionalizing the nanomaterials. To address this limitation, the modification of natural carriers' surface to enhance their stability appears to be a promising strategy. Herein, sulfobetaine methacrylate (SBMA)-functionalized bovine serum albumin (BSA) was synthesized for the first time to investigate the capacity of this modification to improve the resulting nanoparticles' physicochemical properties, colloidal stability and in vitro performance. This novel polymer was then employed in the formulation of nanoparticles loaded with IR780 for application in breast cancer phototherapy (IR/SBMA-BSA NPs). When compared to their non-functionalized equivalents, the IR/SBMA-BSA NPs presented a neutral surface charge and a higher stability in biologically relevant media. Due to these features, the IR/SBMA-BSA NPs could achieve a 1.9-fold greater uptake by breast cancer cells than IR/BSA NPs. Furthermore, the IR/SBMA-BSA NPs were cytocompatible towards normal cells and reduced breast cancer cells' viability up to 42%. The phototherapy mediated by IR/SBMA-BSA NPs could further decrease cancer cells' viability to about 12%. Overall, the IR/SBMA-BSA NPs have enhanced features that propel their application in breast cancer phototherapy.

Tumor cell death in orthotopic breast cancer model by NanoALA: a novel perspective on photodynamic therapy in oncology

Aim: Nano-5-aminolevulic acid (NanoALA)-mediated photodynamic therapy (PDT), an oil-in-water polymeric nanoemulsion of ALA, was evaluated in a murine model of breast cancer. Materials & methods: Analysis of ALA-derived protoporphyrin IX production and acute toxicity test, biocompatibility and treatment efficacy, and long-term effect of NanoALA-PDT on tumor progression were performed. Results: The nanoformulation favored the prodrug uptake by tumor cells in a shorter time (1.5 h). As a result, the adverse effects were negligible and the response rates for primary mammary tumor control were significantly improved. Tumor progression was slower after NanoALA-PDT treatment, providing longer survival. Conclusion: NanoALA is a good proactive drug candidate for PDT against cancer potentially applied as adjuvant/neoadjuvant intervention strategy for breast cancer.

AIEgens Conjugation Improves the Photothermal Efficacy and Near-Infrared Imaging of Heptamethine Cyanine IR-780

Near-infrared (NIR) fluorescent probes can deeply penetrate through tissues with little damage. To facilitate image-guided theranostics, researchers usually apply a desired amount of photosensitizers to achieve effective photothermal responses. However, these probes could easily suffer from low photostability and aggregated-caused quenching effect in high concentrations. In this paper, the rational incorporation of an aggregated-induced emission (AIE) unit into the structure of heptamethine cyanine IR-780 is reported. Using tetraphenylethene (TPE) as an AIE core, we synthesize three TPE-modified IR-780 probes (IR-780 AIEgens) via different linkages. The IR-780 derivatives all show enhanced AIE features, in which the probe with an ether linkage (IR780-O-TPE) is superior in rapid cell uptake, high targeting capacity, and good photostability. Moreover, IR780-O-TPE exhibits the strongest cytotoxicity to HeLa cells (IC₅₀ = 3.3 μM). The three IR-780 derivatives displayed a photothermal response in a concentration-dependent manner, in which IR-780 AIEgens are more cytotoxic than IR-780, with IC₅₀ of 0.3 μM under 808 nm laser irradiation. In tumor-bearing mice, the optimal probe IR780-O-TPE also showed a more effective photothermal response than IR-780. By illustrating the relationship between aggregation state with photophysical properties, cell imaging, and cytotoxicity, this work is helpful in modulating NIR-based photosensitizers into AIE features for efficient image-guided theranostics.

Prototypic Heptamethine Cyanine Incorporating Nanomaterials for Cancer Phototheragnostic

Developing technologies that allow the simultaneous diagnosis and treatment of cancer (theragnostic) has been the quest of numerous interdisciplinary research teams. In this context, nanomaterials incorporating prototypic near infrared (NIR)-light responsive heptamethine cyanines have been showing very promising results for cancer theragnostic. The precisely engineered features of these nanomaterials endow them with the ability to achieve a high tumor accumulation, enabling a tumor's visualization by NIR fluorescence and photoacoustic imaging modalities. Upon interaction with NIR light, the tumor-homed heptamethine cyanine-incorporating nanomaterials can also produce a photothermal/photodynamic effect with a high spatio-temporal resolution and minimal side effects, leading to an improved therapeutic outcome. This progress report analyses the application of nanomaterials incorporating prototypic NIR-light responsive heptamethine cyanines (IR775, IR780, IR783, IR797, IR806, IR808, IR820, IR825, IRDye 800CW, and Cypate) for cancer photothermal therapy, photodynamic therapy, and imaging. Overall, the continuous development of nanomaterials incorporating the prototypic NIR absorbing heptamethine cyanines will cement their phototheragnostic capabilities.

Graphene family nanomaterials for application in cancer combination photothermal therapy

Combining hyperthermia with other therapies holds a great potential for improving cancer treatment. In this approach, the increase in the body temperature can exert a therapeutic effect on cells and/or enhance the effectiveness of anticancer agents. However, the conventional methodologies available to induce hyperthermia cannot confine a high temperature increase to the tumor-site while maintaining healthy tissues unexposed and ensuring minimal invasiveness. To overcome these limitations, combination photothermal therapy (PTT) mediated by graphene family nanomaterials (GFN) has been showing promising results. Such is owed to the ability of GFN to accumulate at the tumor site and convert near infrared light into heat, enabling a hyperthermia with a high spatial-temporal resolution. Furthermore, GFN can also incorporate different therapeutic agents on their structure for delivery purposes to cancer cells. In this way, the combination PTT mediated by GFN can result in an improved therapeutic effect. In this review, the combination of GFN mediated PTT with chemo-, photodynamic-, gene-, radio-, and immuno-therapies is examined. Furthermore, the main parameters that influence these types of combination approaches are also analyzed, with emphasis on the photothermal potential of GFN and on the vascular and cellular effects produced by the temperature increase mediated by GFN.

Self-assembled CeVO4/Au heterojunction nanocrystals for photothermal/photoacoustic bimodal imaging-guided phototherapy

Phototherapy, including photothermal therapy (PTT) and photodynamic therapy (PDT), has attracted great attention because it can effectively inhibit the proliferation and propagation of cancer cells. Recently, heterojunction nanomaterials have shown tremendous application value in the field of biological medicine. In this work, the CeVO4/Au heterojunction nanocrystals (NCs) are designed for photothermal/photoacoustic bimodal imaging-guided phototherapy. The as-synthesized hydrophobic oleic acid (OA)-stabilized CeVO4 nanosheets were modified with HS-PEG-OH for translating into hydrophilic ones, which can significantly improve their stability and biocompatibility. Subsequently, the plasmonic Au nanoparticles were in situ successfully deposited on the surface of HS-PEG-coated CeVO4 to form CeVO4/Au heterojunction NCs for improving the visible and near-infrared light absorption, which results in enhanced photothermal conversion performance and reactive oxygen species (ROS) generation capacity. Thus, the CeVO4/Au can cause more severe damage to cancer cells than pure CeVO4 under NIR laser irradiation. Also, CeVO4/Au can provide distinct tumor contrast by photothermal/photoacoustic bimodal bioimaging. Our results demonstrate that CeVO4/Au NCs could be used as an effective theranostic anticancer agent for near-infrared (NIR) light-mediated PTT and PDT.

Sulfobetaine methacrylate-functionalized graphene oxide-IR780 nanohybrids aimed at improving breast cancer phototherapy

The application of Graphene Oxide (GO) in cancer photothermal therapy is hindered by its lack of colloidal stability in biologically relevant media and modest Near Infrared (NIR) absorption. In this regard, the colloidal stability of GO has been improved by functionalizing its surface with poly(ethylene glycol) (PEG), which may not be optimal due to the recent reports on PEG immunogenicity. On the other hand, the chemical reduction of GO using hydrazine hydrate has been applied to enhance its photothermal capacity, despite decreasing its cytocompatibility. In this work GO was functionalized with an amphiphilic polymer containing [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA) brushes and was loaded with IR780, for the first time, aiming to improve its colloidal stability and phototherapeutic capacity. The attained results revealed that the SBMA-functionalized GO displays a suitable size distribution, neutral surface charge and adequate cytocompatibility. Furthermore, the SBMA-functionalized GO exhibited an improved colloidal stability in biologically relevant media, while its non-SBMA functionalized equivalent promptly precipitated under the same conditions. By loading IR780 into the SBMA-functionalized GO, its NIR absorption increased by 2.7-fold, leading to a 1.2 times higher photothermal heating. In in vitro cell studies, the combination of SBMA-functionalized GO with NIR light only reduced breast cancer cells' viability to 73%. In stark contrast, by combining IR780 loaded SBMA-functionalized GO and NIR radiation, the cancer cells' viability decreased to 20%, hence confirming the potential of this nanomaterial for cancer photothermal therapy.

IR780 loaded SBMA-coated GO displayed an improved colloidal stability in biologically relevant media and an enhanced photothermal capacity.

A new strategy for accurate targeted diagnosis and treatment of cutaneous malignant melanoma: dual-mode phase-change lipid nanodroplets as ultrasound contrast agents

Background

Currently, effective detection and treatment of cutaneous malignant melanoma (CMM) still face severe challenges. Ultrasound molecular imaging as a noninvasive and easy-to-operate method is expected to bring improvements for tumor detection.

Purpose

The aim of this research is to prepare novel phase-change ultrasound contrast agents, Nds-IR780, which can perform not only dual-mode molecule-targeted imaging but also targeted photothermal therapy for CMM.

Methods

A double emulsion process was used to prepare the Nds-IR780. Then, the entrapment rate and drug loading of IR-780 iodide in Nds-IR780 were detected by high-performance liquid chromatography. The biocompatibility of Nds-IR780 was evaluated by a CCK-8 assay and the characteristics and stability of that were verified through the particle size analyzer, laser scanning confocal microscopy (LSCM) and transmission electron microscopy (TEM). The abilities of dual-mode molecule-targeted imaging and targeted photothermal therapy for Nds-IR780 were confirmed via the in vitro and in vivo experiments.

Results

Nds-IR780 had good size distribution, polydispersity index, stability and biosafety. The in vitro and in vivo experiments confirmed that Nds-IR780 were capable of targeting CMM cells with high affinity (22.4±3.2%) and facilitating dual-mode imaging to detect the primary lesion and sentinel lymph nodes (SLNs) of CMM. Furthermore, the photothermal ablation of CMM mediated by Nds-IR780 was very effective in vivo.

Conclusion

The newly prepared Nds-IR780 were observed to be effective targeted theranostic probe for the precise detection and targeted treatment of CMM.

Carbon-gold hybrid nanoprobes for real-time imaging, photothermal/photodynamic and nanozyme oxidative therapy

Rationale: Recently, there is one-fifth of human deaths caused by cancer, leading to cancer treatment remains a hard nut to crack in the medical field. Therefore, as an emerging diagnostic technology, mesoporous nanomaterials-based drug delivery systems integrated diagnosis and therapy have aroused tremendous interest owing to visually targeting effect and superior therapy efficacy compared with traditional cancer treatment. Methods: In this work, we have successfully synthesized mesoporous carbon-gold hybrid nanozyme nanoprobes, whereby mesoporous carbon nanospheres were doped with small gold nanoparticles (OMCAPs) and further stabilized with a complex of reduced serum albumin and folic acid (rBSA-FA). After loading IR780 iodide, the OMCAPs@ rBSA-FA@IR780 nanoprobes were finally accomplished for real-time imaging, photothermal/photodynamic and nanozyme oxidative therapy. Results: Herein, acid oxidized MCAPs possessed large surface area and numerous -COOH groups, which could be used to surface chemically modify numerous targeting molecules and load abundant NIR dye IR780, as well as be acted as photothermal reagents to enhance photothermal therapy effect. In addition, the small Au NPs embedded in OMCAPs were utilized as nanozyme to catalyze H2O2 located in tumor cells to generate ·OH for intracellular oxidative damage of tumor. Besides, as a commonly used near-infrared (NIR) fluorescence dye, the loaded IR780 iodide could not only apply for real-time imaging, but also effectively enhance photo-thermal therapy (PTT) upon the 808 nm laser irradiation. Moreover, FA molecules could enhance the targeted efficiency of the nanoprobes to the gastric tumor site. According to the systematical study in vitro and in vivo, our fabricated nanoprobes based on carbon-gold hybrid (OMCAPs@ rBSA-FA@IR780) revealed excellent tumor targeting efficacy, long tumor retention and favorably therapeutic effect for tumor. Conclusion: All the results demonstrated that here synthesized probes exhibited excellently diagnostic and therapeutic performance, indicating our technology may potentially offer an outstanding strategy for tumor-targeting theranostics.

Hybrid curcumin-phospholipid complex-near-infrared dye oral drug delivery system to inhibit lung metastasis of breast cancer

Background: Oral route of administration is preferred for treating breast cancer, especially when continued disease management with good tolerability is required; however, orally administered chemotherapeutics combined with near-infrared (NIR) dyes are hindered by the low bioavailability, insufficient for the desired therapeutic efficacy. In this study, we developed a hybrid self-microemulsifying drug delivery system for co-loading curcumin–phospholipid complex and NIR dye IR780 (CUR/IR780@SMEDDS), to achieve combined phototherapeutic and chemotherapeutic effects against lung metastasis of breast cancer.

Methods: CUR/IR780@SMEDDS were characterized. The efficacy against breast cancer metastasis was evaluated by photothermal and photodynamic assessment, cytotoxicity, invasion, and migration in metastatic 4T1 breast cancer cells in vitro, and in vivo oral bioavailability study in rats and pharmacodynamics studies in tumor-bearing nude mice.

Results: CUR/IR780@SMEDDS improved oral bioavailability of curcumin and IR780 in rats compared with curcumin and IR780 suspensions. CUR/IR780@SMEDDS exhibited remarkable photothermal and photodynamic effects in vitro. In metastatic 4T1 breast cancer cells, CUR/IR780@SMEDDS combined with localized NIR laser irradiation induced significant cytotoxicity and inhibited invasion and migration of 4T1 cells, an outcome attributable to cumulative effects of IR780-induced hyperthermia and pharmacological effects of curcumin. In orthotopic 4T1 tumor-bearing nude mice, combination of oral administration of CUR/IR780@SMEDDS with local NIR laser irradiation inhibited tumor progression and suppressed lung metastasis.

Temporally Controlled Photothermal/Photodynamic and Combined Therapy for Overcoming Multidrug Resistance of Cancer by Polydopamine Nanoclustered Micelles

Currently, the simple integration of multiple therapeutic agents within a single nanostructure for combating multidrug resistance (MDR) tumors yet remains a challenge. Herein, we report a photoresponsive nanocluster (NC) system prepared by installing polydopamine (PDA) nanoparticle clusters on the surface of d-α-tocopheryl poly(ethylene glycol) 1000 succinate (TPGS) (a drug efflux inhibitor) micelles solubilized with IR780 (a photosensitizer) to achieve a combined chemotherapy (CT)/photothermal therapy (PTT)/photodynamic therapy (PDT) for drug-resistant breast cancer. Mediated by the fluorescence resonance energy transfer and radical scavenging properties of PDA, NC shows prominently quenched fluorescence emission (∼78%) and inhibited singlet oxygen generation (∼67%) upon exposure to near-infrared (NIR) light (808 nm, 0.5 W cm^-2), favoring a highly efficient PTT module. Meanwhile, the photothermal heat can also boost the release of doxorubicin hydrochloride whose intracellular accumulation can be greatly enhanced by TPGS. Interestingly, the first NIR irradiation and subsequent incubation (∼24 h) can induce the gradual relocation and disintegration of PDA nanoparticles, thereby leading to activated PDT therapy under the second irradiation. Upon the temporally controlled sequential application of PTT/PDT, the developed NC exhibited a great potential to treat MDR cancer both in vitro and in vivo. These findings suggest that complementary interactions among PTT/PDT/CT modalities can enhance the efficiency of the combined therapy for MDR tumor.

Hyaluronic acid and polydopamine functionalized phase change nanoparticles for ultrasound imaging-guided photothermal-chemotherapy

Hyaluronic acid and polydopamine functionalized phase change nanoparticles for ultrasound imaging-guided photothermal-chemotherapy.

Near-infrared-induced IR780-loaded PLGA nanoparticles for photothermal therapy to treat breast cancer metastasis in bones

Nanodrug-based cancer therapy, especially when treating bone metastases, faces the problem of limited therapeutic efficacy. In this work, we reported a photothermally triggered nanomaterial based on IR780-entrapped poly-lactide-co-glycolide (PLGA) nanoparticles (IR780@PLGA NPs) for the photothermal therapy of bone metastases of breast cancer, in which IR780 converted light into heat to play a role in “burning” the tumors. Anti-tumor therapy studies showed the impressive effectiveness of IR780@PLGA NPs in the photothermal therapy (PTT) of bone metastases. As a result, the IR780@PLGA NPs show a great potential for controlling the bone metastases of breast cancer.

A schematic of PTT using IR780@PLGA NPs with NIR laser-controlled IR780 release.

Magnetically targeted nanoparticles for imaging-guided photothermal therapy of cancer

Over the past several decades, nanocarriers have constituted a vital research area for accurate tumor therapy. Herein, magnetically targeted nanoparticles (IRFes) for photothermal therapy were generated by integrating IR780, a molecule with strong emission and absorption in the NIR spectrum and the ability to produce heat after laser irradiation, with Fe₃O₄ nanoparticles (NPs). These IRFes were guided to the tumor site by the application of an external magnetic field. In particular, the strong NIR absorption of IR780 was used for NIRF imaging, and we also demonstrated effective magnetic targeting for the photothermal ablation of tumors. In vitro cell viability and in vivo antitumor experiments showed that these IRFes can ablate 4T1 cells or transplanted 4T1 cell tumors when exposed to 808 nm laser irradiation and a magnetic field. In vivo experiments showed that IRFes only act on tumors, do not damage other organs and can be used to image tumors. These results demonstrate the enormous potential of local photothermal therapy for cancer under the guidance of external magnetic fields and reveal the prospect for the use of multifunctional nanoparticles in tumor therapy.

Magnetically targeted nanoparticles (IRFes) for photothermal therapy were generated by integrating IR780, a molecule with strong emission and absorption in the NIR spectrum and the ability to produce heat after laser irradiation, with Fe₃O₄ nanoparticles.

Establishment of 2D Cell Cultures Derived From 3D MCF-7 Spheroids Displaying a Doxorubicin Resistant Profile

In vitro 3D cancer spheroids generally exhibit a drug resistance profile similar to that found in solid tumors. Due to this property, these models are an appealing for anticancer compounds screening. Nevertheless, the techniques and methods aimed for drug discovery are mostly standardized for cells cultured in 2D. The development of 2D cell culture models displaying a drug resistant profile is required to mimic the in vivo tumors, while the equipment, techniques, and methodologies established for conventional 2D cell cultures can continue to be employed in compound screening. In this work, the response of 3D-derived MCF-7 cells subsequently cultured in 2D in medium supplemented with glutathione (GSH) (antioxidant agent found in high levels in breast cancer tissues and a promoter of cancer cells resistance) to Doxorubicin (DOX) is evaluated. These cells demonstrated a resistance toward DOX closer to that displayed by 3D spheroids, which is higher than that exhibited by standard 2D cell cultures. In fact, the 50% inhibitory concentration (IC₅₀ ) of DOX in 3D-derived MCF-7 cell cultures supplemented with GSH is about eight-times higher than that obtained for conventional 2D cell cultures (cultured without GSH), and is only about two-times lower than that attained for 3D MCF-7 spheroids (cultured without GSH). Further investigation revealed that this improved resistance of 3D-derived MCF-7 cells may result from their increased P-glycoprotein (P-gp) activity and reduced production of intracellular reactive oxygen species (ROS).