Targeted photodynamic-induced singlet oxygen production by peptide-conjugated biodegradable nanoparticles for treatment of skin melanoma

The phototoxic effect of a gold-antibody-based nanocarrier of phthalocyanine on melanoma monolayers and tumour spheroids

In recent years, photodynamic therapy (PDT) has garnered significant attention in cancer treatment due to its increased potency and non-invasiveness compared to conventional therapies. Active-targeted delivery of photosensitizers (PSs) is a mainstay strategy to significantly reduce its off-target toxicity and enhance its phototoxic efficacy. The anti-melanoma inhibitory activity (MIA) antibody is a targeting biomolecule that can be integrated into a nanocarrier system to actively target melanoma cells due to its specific binding to MIA antigens that are highly expressed on the surface of melanoma cells. Gold nanoparticles (AuNPs) are excellent nanocarriers due to their ability to encapsulate a variety of therapeutics, such as PSs, and their ability to bind with targeting moieties for improved bioavailability in cancer cells. Hence, we designed a nanobioconjugate (NBC) composed of zinc phthalocyanine tetrasulfonic acid (ZnPcS4), AuNPs and anti-MIA Ab to improve ZnPcS4 bioavailability and phototoxicity in two and three-dimensional tumour models. In summary, we demonstrated that this nanobioconjugate showed significant inhibitory effects on both melanoma models due to increased ROS yields and bioavailability of the melanoma cells compared to free ZnPcS4.

Multitarget, multiagent PLGA nanoparticles for simultaneous tumor eradication and TME remodeling in a melanoma mouse model

Despite the fact that chemoimmunotherapy has emerged as a key component in the era of cancer immunotherapy, it is challenged by the complex tumor microenvironment (TME) that is jam-packed with cellular and non-cellular immunosuppressive components. The aim of this study was to design a nanoparticulate system capable of sufficiently accumulating in the tumor and spleen to mediate local and systemic immune responses, respectively. The study also aimed to remodel the immunosuppressive TME. For such reasons, multi-functional polylactic-co-glycolic acid (PLGA) nanoparticles (NPs) were engineered to simultaneously eradicate the cancer cells, silence the tumor-associated fibroblasts (TAFs), and re-educate the tumor-associated macrophages (TAMs) using doxorubicin, losartan, and metformin, respectively. These agents were also selected for their ability to tip the balance of the splenic immune cells towards immunostimulatory phenotypes. To establish TAM and TAF cultures, normal macrophages and fibroblasts were incubated with B16F10 melanoma cell (Mel)-derived secretome. Drug-loaded PLGA NPs were prepared, characterized, and tested in the target cell types. Organ distribution of fluorescein-loaded PLGA NPs was evaluated in a mouse model of melanoma. Finally, the local and systemic effects of different combination therapy programs were portrayed. The in vitro studies showed that the drug-loaded PLGA NPs could significantly ablate the immunosuppressive nature of Mel and skew TAMs and TAFs towards more favorable phenotypes. While in vivo, PLGA NPs were proven to exhibit long blood circulation time and to localize preferentially in the tumor and the spleen. The combination of either metformin or losartan with doxorubicin was superior to the monotherapy, both locally and systemically. However, the three-agent combo produced detrimental effects in the form of compromised well-being, immune depletion, and metastasis. These findings indicate the potential of TME remodeling as means to prime the tumors for successful chemoimmunotherapy. In addition, they shed light on the importance of the careful use of combination therapies and the necessity of employing dose-reduction strategies. D-NPs doxorubicin-loaded NPs, M-NPs metformin-loaded NPs, L-NPs losartan-loaded NPs, TAMs tumor-associated macrophages, TAFs tumor-associated fibroblasts, PD-L1 programmed death ligand 1, TNF-α tumor necrosis factor alpha, TGF-β transforming growth factor beta, CD206/40/86 cluster of differentiation 206/40/86, α-SMA alpha-smooth muscle actin, MMPs matrix metalloproteases.

Phytochemical-derived tumor-associated macrophage remodeling strategy using Phoenix dactylifera L. boosted photodynamic therapy in melanoma via H19/iNOS/PD-L1 axis

BACKGROUND

The tumor microenvironment (TME) represents a barrier to PDT efficacy among melanoma patients. The aim of this study is to employ a novel muti-tactic TME-remodeling strategy via repolarization of tumor-associated macrophages (TAMs), the main TME immune cells in melanoma, from the pro-tumor M2 into the antitumor M1 phenotype using Phoenix dactylifera L. (date palm) in combination with PDT.

METHODS

Screening of different date cultivars was employed to choose extracts of selective toxicity to melanoma and TAMs, not normal macrophages. Potential extracts were then fractionated and characterized by gas chromatography-mass spectrometry (GC-MS). Finally, the efficacy and the potential molecular mechanism of the co-treatment were portrayed via quantitative real-time polymerase chain reaction (qRT-PCR) analysis.

RESULTS

Initial screening resulted in the selection of the two Phoenix dactylifera L. cultivars Safawi and Sukkari methanolic extracts. Sukkari showed superior capacity to revert TAM phenotype into M1 as well as more prominent upregulation of M1 markers and repression of melanoma immunosuppressive markers relative to positive control (resiquimod). Molecularly, it was shown that PDT of melanoma cells in the presence of the secretome of repolarized TAMs surpassed the monotherapy via the modulation of the H19/iNOS/PD-L1immune-regulatory axis.

CONCLUSION

This study highlights the potential utilization of nutraceuticals in combination with PDT in the treatment of melanoma to provide a dual activity through alleviating the immune suppressive TME and potentiating the anti-tumor responses.

Drugless nanoparticles tune-up an array of intertwined pathways contributing to immune checkpoint signaling and metabolic reprogramming in triple-negative breast cancer

Metabolic reprogramming 'Warburg effect' and immune checkpoint signaling are immunosuppressive hallmarks of triple-negative breast cancer (TNBC) contributing to the limited clinical applicability of immunotherapy. Biomaterials arise as novel tools for immunomodulation of the tumor microenvironment that can be used alongside conventional immunotherapeutics. Chitosan and lecithin are examples of versatile biomaterials with interesting immunomodulatory properties. In this study, we aimed at investigation of the role of carefully designed hybrid nanoparticles (NPs) on common mediators of both programmed death ligand 1 (PD-L1) expression and glycolytic metabolism. Hybrid lecithin-chitosan NPs were prepared and characterized. Their intracellular concentration, localization and effect on the viability of MDA-MB-231 cells were assessed. Glycolytic metabolism was quantified by measuring glucose consumption, adenosine triphosphate (ATP) generation, lactate production and extracellular acidification. Nitric oxide production was quantified using Greiss reagent. Gene expression of inducible nitric oxide synthase (iNOS), phosphatidylinositol-3-kinase (PI3K), protein kinase B (PKB or Akt), mammalian target of rapamycin (mTOR), hypoxia-inducible factor 1α(HIF-1α) and PD-L1 was quantified by quantitative reverse transcription polymerase chain reaction (q-RT-PCR). Chitosan, lecithin and the NPs-formulated forms have been shown to influence the 'Warburg effect' and immune checkpoint signaling of TNBC cells differently. The composition of the hybrid systems dictated their subcellular localization and hence the positive or negative impact on the immunosuppressive characteristics of TNBC cells. Carefully engineered hybrid lecithin-chitosan NPs could convert the immune-suppressive microenvironment of TNBC to an immune-active microenvironment via reduction of PD-L1 expression and reversal of the Warburg effect.

Recent advances in nanotechnology based combination drug therapy for skin cancer

Skin-cancer (SC) is more common than all other cancers affecting large percentage of the population in the world and is increasing in terms of morbidity and mortality. In the United States, 3million people are affected by SC annually whereas millions of people are affected globally. Melanoma is fifth most common cancer in the United States. SC is commonly occurred in white people as per WHO. SC is divided into two groups, i.e. melanoma and non-melanoma. In the previous two decades, management of cancer remains to be a tough and a challenging task for many scholars. Presently, the treatment protocols are mostly based on surgery and chemo-radiation therapy, which sooner or later harm the unaffected cells too. To reduce these limitations, nano scaled materials and its extensive range may be recognized as the probable carriers for the selective drug delivery in response to cancerous cells. Recently, the nanocarriers based drugs and their combinations were found to be a new and interesting approach of study for the management of skin carcinoma to enhance the effectiveness, to lessen the dose-dependent side effects and to avoid the drug resistance. This review may emphasize on the wide-range of information on nanotechnology-based drugs and their combination with physical techniques.

Eutectic Gallium-Indium Nanoparticles for Photodynamic Therapy of Pancreatic Cancer

Developing a cancer theranostic nanoplatform with diagnosis and treatment capabilities to effectively treat tumors and reduce side effects is of great significance. Herein, we present a drug delivery strategy for photosensitizers based on a new liquid metal nanoplatform that leverages the tumor microenvironment to achieve photodynamic therapeutic effects in pancreatic cancer. Eutectic gallium indium (EGaIn) nanoparticles were successfully conjugated with a water-soluble cancer targeting ligand, hyaluronic acid, and a photosensitizer, benzoporphyrin derivative, creating EGaIn nanoparticles (EGaPs) via a simple green sonication method. The prepared sphere-shaped EGaPs, with a core-shell structure, presented high biocompatibility and stability. EGaPs had greater cellular uptake, manifested targeting competence, and generated significantly higher intracellular ROS. Further, near-infrared light activation of EGaPs demonstrated their potential to effectively eliminate cancer cells due to their single oxygen generation capability. Finally, from in vivo studies, EGaPs caused tumor regression and resulted in 2.3-fold higher necrosis than the control, therefore making a good vehicle for photodynamic therapy. The overall results highlight that EGaPs provide a new way to assemble liquid metal nanomaterials with different ligands for enhanced cancer therapy.

Nanoparticle-Based Drug Delivery Systems for Photodynamic Therapy of Metastatic Melanoma: A Review

Metastatic melanoma (MM) is a skin malignancy arising from melanocytes, the incidence of which has been rising in recent years. It poses therapeutic challenges due to its resistance to chemotherapeutic drugs and radiation therapy. Photodynamic therapy (PDT) is an alternative non-invasive modality that requires a photosensitizer (PS), specific wavelength of light, and molecular oxygen. Several studies using conventional PSs have highlighted the need for improved PSs for PDT applications to achieve desired therapeutic outcomes. The incorporation of nanoparticles (NPs) and targeting moieties in PDT have appeared as a promising strategy to circumvent various drawbacks associated with non-specific toxicity, poor water solubility, and low bioavailability of the PSs at targeted tissues. Currently, most studies investigating new developments rely on two-dimensional (2-D) monocultures, which fail to accurately mimic tissue complexity. Therefore, three-dimensional (3-D) cell cultures are ideal models to resemble tumor tissue in terms of architectural and functional properties. This review examines various PS drugs, as well as passive and active targeted PS nanoparticle-mediated platforms for PDT treatment of MM on 2-D and 3-D models. The overall findings of this review concluded that very few PDT studies have been conducted within 3-D models using active PS nanoparticle-mediated platforms, and so require further investigation.

Green Synthesized Honokiol Transfersomes Relieve the Immunosuppressive and Stem-Like Cell Characteristics of the Aggressive B16F10 Melanoma

BACKGROUND

Honokiol (HK) is a natural bioactive compound with proven antineoplastic properties against melanoma. However, it shows very low bioavailability when administered orally. Alternatively, topical administration may offer a promising route. The objective of the current study was to fabricate HK transfersomes (HKTs) for topical treatment of melanoma. As an ultradeformable carrier system, transfersomes can overcome the physiological barriers to topical treatment of melanoma: the stratum corneum and the anomalous tumor microenvironment. Moreover, the immunomodulatory and stemness-regulation roles of HKTs were the main interest of this study.

METHODS

TFs were prepared using the modified scalable heating method. A three-factor, three-level Box-Behnken design was utilized for the optimization of the process and formulation variables. Intracellular uptake and cytotoxicity of HKTs were evaluated in nonactivated and stromal cell-activated B16F10 melanoma cells to investigate the influence of the complex tumor microenvironment on the efficacy of HK. Finally, ELISA and Western blot were performed to evaluate the expression levels of TGF-β and clusters of differentiation (CD47 and CD133, respectively).

RESULTS

The optimized formula exhibited a mean size of 190 nm, highly negative surface charge, high entrapment efficiency, and sustained release profile. HKTs showed potential to alleviate the immunosuppressive characteristics of B16F10 melanoma in vitro via downregulation of TGF-β signaling. In addition, HKTs reduced expression of the "do not eat me" signal - CD47. Moreover, HKTs possessed additional interesting potential to reduce the expression of the stem-like cell marker CD133. These outcomes were boosted upon combination with metformin, an antihyperglycemic drug recently reported to possess different functions in cancer, while combination with collagenase, an extracellular matrix-depleting enzyme, produced detrimental effects.

CONCLUSION

HKTs represent a promising scalable formulation for treatment of the aggressive B16F10 melanoma, which is jam-packed with immunosuppressive and stem-like cell markers.

Nanocarriers for Photodynamic Therapy Intended to Cutaneous Tumors

Photodynamic Therapy (PDT) is a therapeutic modality used for several malignant and premalignant skin disorders, including Bowen's disease skin cancers and Superficial Basal Cell Carcinoma (BCC). Several photosensitizers (PSs) have been explored for tumor destruction of skin cancers, after their activation by a light source of appropriate wavelength. Topical release of PSs avoids prolonged photosensitization reactions associated with systemic administration; however, its clinical usefulness is influenced by its poor tissue penetration and the stability of the active agent. Nanotechnology-based drug delivery systems are promising tool to enhance the efficiency for PDT of cancer. This review focuses on PSs encapsulated in nanocarriers explored for PDT of skin tumors.

Protoporphyrin IX (PpIX) loaded PLGA nanoparticles for topical Photodynamic Therapy of melanoma cells

INTRODUCTION

Nanoparticles (Np) can increase drug efficacy and overcome problems associated with solubility and aggregation in a solution of PpIX.

PURPOSE

Evaluate if Np interferes in the photophysical and photobiological capacity of the PpIX comparing with free PpIX intended for topical PDT of melanoma.

METHODS

In vitro photophysical evaluation of Np-PpIX was carried out through singlet oxygen (₁O²) quantum yield. In vitro cytotoxicity and phototoxicity assays have used murine melanoma cell culture.

RESULTS

The quantum yield of singlet oxygen has shown that Np did not influence the formation capacity of this reactive species. In the dark, all PpIX-Nps concentrations were less cytotoxic compared to free drugs. At a higher light dose (1500 mJ.cm²) 3.91 μg / mL PpIX had similar % viable cells for free and Np (∼34 %) meaning Nps did not interfere in the photodynamic effect of PpIX. However, at 7.91 μg / mL the phototoxicity increased for both (5.8 % viable cells for free versus 21.7 % for Nps). Despite the higher phototoxicity of free PpIX at this concentration, greater cytotoxicity in the dark was obtained (∼49 % viable cells for free versus ∼90.6 % Np) which means Nps protect the tumor tissue from the photodynamic action of PpIX.

CONCLUSIONS

Np is a potential delivery system for melanoma skin cancer, since it maintained the photophysical properties of PpIX and excellent in vitro phototoxicity effect against melanoma cells, reducing cell viability ∼80 % (7.91 μg / mL PpIX in Nps) and provides safe PDT (due to lower cytotoxicity in the dark).

Novel Targeted Photosensitizer as an Immunomodulator for Highly Efficient Therapy of T-Cell Acute Lymphoblastic Leukemia

Dasatinib is a kinase-targeted drug used in the treatment of leukemia. Regrettably, it remains far from optimal medicine due to insurmountable drug resistance and side effects. Photodynamic therapy (PDT) has proven that it can induce systemic immune responses. However, conventional photosensitizers as immunomodulators produce anticancer immunities, which are inadequate to eliminate residual cancer cells. Herein, a novel compound 4 was synthesized and investigated, which introduces dasatinib and zinc(II) phthalocyanine as the targeting and photodynamic moiety, respectively. Compound 4 exhibits a high affinity to CCRF-CEM cells/tumor tissues, which overexpress lymphocyte-specific protein tyrosine kinase (LCK), and preferential elimination from the body. Meanwhile, compound 4 shows excellent photocytotoxicity and tumor regression. Significantly, compound 4-induced PDT can obviously enhance immune responses, resulting in the production of more immune cells. We believe that the proposed manner is a potential strategy for the treatment of T-cell acute lymphoblastic leukemia.

Distinct Proteins in Protein Corona of Nanoparticles Represent a Promising Venue for Endogenous Targeting - Part I: In vitro Release and Intracellular Uptake Perspective

Introduction

Protein corona (PC) deposition on nanoparticles (NPs) in biological systems contributes to a great extent to NPs' fates; their targeting potential, the interaction with different biological systems and the subsequent functions. PC - when properly tuned - can serve as a potential avenue for optimization of NPs' use in cancer therapy.

Methods

Poly-lactic co-glycolic acid (PLGA)-based NPs exhibiting different physicochemical properties were fabricated and characterized. The PC makeup of these NPs were qualitatively and quantitatively analyzed by Western blot and Bradford assay, respectively. The effect of PC on the release of NPs' cargos and the intracellular uptake into B16F10 melanoma cells has been studied.

Results

The composition of NPs (polymeric PLGA NPs vs lipid-polymer hybrid NPs) and the conjugation of an active targeting ligand (cRGDyk peptide) represented the major determinants of the PC makeup of NPs. The in vitro release of the loaded cargos from the NPs depended on the PC and the presence of serum proteins in the release medium. Higher cumulative release has been recorded in the presence of proteins in the case of peptide conjugated NPs, cNPs, while the unconjugated formulations, uNPs, showed an opposite pattern. NPs intracellular uptake studies revealed important roles of distinct serum and cellular proteins on the extent of NPs' accumulation in melanoma cells. For example, the abundance of vitronectin (VN) protein from serum has been positively related to the intracellular accumulation of the NPs.

Conclusion

Careful engineering of nanocarriers can modulate the recruitment of some proteins suggesting a potential use for achieving endogenous targeting to overcome the current limitations of targeted delivery of chemotherapeutic agents.

Stimuli-responsive and cellular targeted nanoplatforms for multimodal therapy of skin cancer

Interdisciplinary applications of nanopharmaceutical sciences have tremendous potential for enhancing pharmacokinetics, efficacy and safety of cancer therapy. The limitations of conventional therapeutic platforms used for skin cancer therapy have been largely overcome by the use of nanoplatforms. This review discusses various nanotechnological approaches experimented for the treatment of skin cancer. The review describes various polymeric, lipidic and inorganic nanoplatforms for efficient therapy of skin cancer. The stimuli-responsive nanoplatforms such as pH-responsive as well as temperature-responsive platforms have also been reviewed. Different strategies for potentiating the nanoparticles application for cancer therapy such as surface engineering, conjugation with drugs, stimulus-responsive and multimodal effect have also been discussed and compared with the available conventional treatments. Although, nanopharmaceuticals face challenges such as toxicity, cost and scale-up, efforts put-in to improve these drawbacks with continuous research would deliver exciting and promising results in coming days.

A Naturally Derived Carrier for Photodynamic Treatment of Squamous Cell Carcinoma: In Vitro and In Vivo Models

Photodynamic therapy (PDT) is a non-invasive treatment strategy that includes the combination of three components-a photosensitizer, a light source, and tissue oxygen. PDT can be used for the treatment of skin diseases such as squamous cell carcinoma. The photosensitizer used in this study is the naturally derived chlorophyll derivative chlorin e6 (Ce6), which was encapsulated in ultradeformable ethosomes. Singlet oxygen production by Ce6 upon laser light irradiation was not significantly affected by encapsulation into ethosomes. PDT of squamous cell carcinoma cells treated with Ce6 ethosomes triggered increased mitochondrial superoxide levels and increased caspase 3/7 activity, resulting in concentration- and light-dose-dependent cytotoxicity. Ce6 ethosomes showed good penetration into 3D squamous cell carcinoma spheroids, which upon laser light irradiation exhibited reduced size, proliferation, and viability. The PDT effect of Ce6 ethosomes was specific and showed higher cytotoxicity against squamous cell carcinoma spheroids compared to normal skin fibroblast spheroids. In addition, PDT treatment of squamous cell carcinoma xenografts grown on chorioallantoic membranes of chick eggs (CAM) exhibited reduced expression of Ki-67 proliferation marker and increased terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) staining, indicating reduced proliferation and activation of apoptosis, respectively. The results demonstrate that Ce6-loaded ethosomes represent a convenient formulation for photodynamic treatment of squamous cell carcinoma.

Flow-induced Shear Stress Confers Resistance to Carboplatin in an Adherent Three-Dimensional Model for Ovarian Cancer: A Role for EGFR-Targeted Photoimmunotherapy Informed by Physical Stress

A key reason for the persistently grim statistics associated with metastatic ovarian cancer is resistance to conventional agents, including platinum-based chemotherapies. A major source of treatment failure is the high degree of genetic and molecular heterogeneity, which results from significant underlying genomic instability, as well as stromal and physical cues in the microenvironment. Ovarian cancer commonly disseminates via transcoelomic routes to distant sites, which is associated with the frequent production of malignant ascites, as well as the poorest prognosis. In addition to providing a cell and protein-rich environment for cancer growth and progression, ascitic fluid also confers physical stress on tumors. An understudied area in ovarian cancer research is the impact of fluid shear stress on treatment failure. Here, we investigate the effect of fluid shear stress on response to platinum-based chemotherapy and the modulation of molecular pathways associated with aggressive disease in a perfusion model for adherent 3D ovarian cancer nodules. Resistance to carboplatin is observed under flow with a concomitant increase in the expression and activation of the epidermal growth factor receptor (EGFR) as well as downstream signaling members mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK) and extracellular signal-regulated kinase (ERK). The uptake of platinum by the 3D ovarian cancer nodules was significantly higher in flow cultures compared to static cultures. A downregulation of phospho-focal adhesion kinase (p-FAK), vinculin, and phospho-paxillin was observed following carboplatin treatment in both flow and static cultures. Interestingly, low-dose anti-EGFR photoimmunotherapy (PIT), a targeted photochemical modality, was found to be equally effective in ovarian tumors grown under flow and static conditions. These findings highlight the need to further develop PIT-based combinations that target the EGFR, and sensitize ovarian cancers to chemotherapy in the context of flow-induced shear stress.

Photodynamic Therapy and the Biophysics of the Tumor Microenvironment

Targeting the tumor microenvironment (TME) provides opportunities to modulate tumor physiology, enhance the delivery of therapeutic agents, impact immune response and overcome resistance. Photodynamic therapy (PDT) is a photochemistry-based, nonthermal modality that produces reactive molecular species at the site of light activation and is in the clinic for nononcologic and oncologic applications. The unique mechanisms and exquisite spatiotemporal control inherent to PDT enable selective modulation or destruction of the TME and cancer cells. Mechanical stress plays an important role in tumor growth and survival, with increasing implications for therapy design and drug delivery, but remains understudied in the context of PDT and PDT-based combinations. This review describes pharmacoengineering and bioengineering approaches in PDT to target cellular and noncellular components of the TME, as well as molecular targets on tumor and tumor-associated cells. Particular emphasis is placed on the role of mechanical stress in the context of targeted PDT regimens, and combinations, for primary and metastatic tumors.

Nanotechnology approaches in the current therapy of skin cancer

Skin cancer is a high burden disease with a high impact on global health. Conventional therapies have several drawbacks; thus, the development of effective therapies is required. In this context, nanotechnology approaches are an attractive strategy for cancer therapy because they enable the efficient delivery of drugs and other bioactive molecules to target tissues with low toxic effects. In this review, nanotechnological tools for skin cancer will be summarized and discussed. First, pathology and conventional therapies will be presented, followed by the challenges of skin cancer therapy. Then, the main features of developing efficient nanosystems will be discussed, and next, the most commonly used nanoparticles (NPs) described in the literature for skin cancer therapy will be presented. Subsequently, the use of NPs to deliver chemotherapeutics, immune and vaccine molecules and nucleic acids will be reviewed and discussed as will the combination of physical methods and NPs. Finally, multifunctional delivery systems to codeliver anticancer therapeutic agents containing or not surface functionalization will be summarized.

Verteporfin-loaded mesoporous silica nanoparticles inhibit mouse melanoma proliferation in vitro and in vivo

Melanoma is one of the most lethal tumors among the skin cancers, arising from complex genetic mutations in melanocyte. Melanoma microenvironment is very heterogeneous, showing complex vascular networks and immunogenicity, as well as induced acquired resistance to treatments by upregulation of multidrug resistance (MDR) mechanisms. Different studies have showed that Photodynamic Therapy (PDT) could be considered a new potential approach for melanoma treatment. PDT combines a light with a specific wavelength and a photosensitizer: when these two elements interact reactive oxygen species (ROS) are generated leading to tumor cell destruction. In this study verteporfin (Ver), a second-generation photosensitizer, has been conjugated with mesoporous silica nanoparticles (MSNs): the resulting Ver-MSNs are an efficient nanoplatforms used to enhance cargo capacity and cellular uptake. Our in vitro and in vivo studies investigated whether Ver-MSNs were able to reduce or inhibit melanoma growth. In vitro experiments performed using B16F10 mouse melanoma cells showed that Ver-MSNs stimulated by red light (693 nm) significantly decreased in vitro cells proliferation in a range of concentration between 0.1 μg/ml to 10 μg/ml. When Ver-MSNs (5 μg/ml in glycerol) were topically administrated to melanoma tumor mass developed in mice and stimulated by red light for four times in 16 days, they were able to reduce the tumor mass of 50.2 ± 6,6% compared to the untreated (only glycerol) mice. In the light of this information, PDT performed using Ver-MSNs could be considered a new promising and potential approach to treat melanoma.

Nanolipid Formulations of Benzoporphyrin Derivative: Exploring the Dependence of Nanoconstruct Photophysics and Photochemistry on Their Therapeutic Index in Ovarian Cancer Cells

With the rapidly emerging designs and applications of light-activated, photodynamic therapy (PDT)-based nanoconstructs, photonanomedicines (PNMs), an unmet need exists to establish whether conventional methods of photochemical and photophysical characterization of photosensitizers are relevant for evaluating new PNMs in order to intelligently guide their design. As a model system, we build on the clinical formulation of benzoporphyrin derivative (BPD), Visudyne^® , by developing a panel of nanolipid formulations entrapping new lipidated chemical variants of BPD with differing chemical, photochemical and photophysical properties. These are 16:0 and 20:0 lysophosphocholine-BPD (16:0/20:0 BPD-PC), DSPE-PEG-BPD and BPD-cholesterol. We show that Visudyne^® was the most phototoxic formulation to OVCAR-5 cells, and the least effective was liposomal DSPE-PEG-BPD. However, these differences did not match their optical, photophysical and photochemical properties, as the static BPD quenching was highest in Visudyne, which also exhibited the lowest generation of singlet oxygen. Furthermore, we establish that OVCAR-5 cell phototoxicity also does not correlate with rates of photosensitizer photobleaching and fluorescence quantum yields in any nanolipid formulations. These findings warrant critical future studies into subcellular targets and molecular mechanisms of phototoxicity of photodynamic nanoconstructs, as more reliable prognostic surrogates for predicting efficacy to appropriately and intelligently guide their design.