Light-Responsive Elastin-Like Peptide-Based Targeted Nanoparticles for Enhanced Spheroid Penetration.

We describe here a near infrared light-responsive elastin-like peptide (ELP)-based targeted nanoparticle (NP) that can rapidly switch its size from 120 to 25 nm upon photo-irradiation. Interestingly, the targeting function, which is crucial for effective cargo delivery, is preserved after transformation. The NPs are assembled from (targeted) diblock ELP micelles encapsulating photosensitizer TT1-monoblock ELP conjugates. Methionine residues in this monoblock are photo-oxidized by singlet oxygen generated from TT1, turning the ELPs hydrophilic and thus trigger NP dissociation. Phenylalanine residues from the diblocks then interact with TT1 via π-π stacking, inducing the re-formation of smaller NPs. Due to their small size and targeting function, the NPs penetrate deeper in spheroids and kill cancer cells more efficiently compared to the larger ones. This work could contribute to the design of "smart" nanomedicines with deeper penetration capacity for effective anticancer therapies.

Glycosylated BODIPY- Incorporated Pt(II) Metallacycles for Targeted and Synergistic Chemo-Photodynamic Therapy.

Pt(II)-BODIPY complexes combine the chemotherapeutic activity of Pt(II) with the photocytotoxicity of BODIPYs. Additional conjugation with targeting ligands can boost the uptake by cancer cells that overexpress the corresponding receptors. We describe two Pt(II) triangles, 1 and 2, built with pyridyl BODIPYs functionalized with glucose (3) or triethylene glycol methyl ether (4), respectively. Both 1 and 2 showed higher singlet oxygen quantum yields than 3 and 4, due to the enhanced singlet-to-triplet intersystem crossing. To evaluate the targeting effect of the glycosylated derivative, in vitro experiments were performed using glucose transporter 1 (GLUT1)-positive HT29 and A549 cancer cells, and noncancerous HEK293 cells as control. Both 1 and 2 showed higher cellular uptake than 3 and 4. Specifically, 1 was selective and highly cytotoxic toward HT29 and A549 cells. The synergistic chemo- and photodynamic behavior of the metallacycles was also confirmed. Notably, 1 exhibited superior efficacy toward the cisplatin-resistant R-HepG2 cells.

Porphyrin-based supramolecular nanofibres as a dynamic and activatable photosensitiser for photodynamic therapy.

Photodynamic therapy (PDT) represents a promising treatment modality for a range of cancers and other non-malignant diseases due to its non-invasive nature arising from the light-dependent activation. However, PDT has not been the first-line treatment of cancer thus far as a consequence of, among others, the lack of effective transport and activation strategies, and the undesired side effect caused by skin photosensitisation induced by the "always on" photosensitisers. To overcome this "Achilles' heel", we present herein a non-covalent approach to construct a one-component dynamic supramolecular nanophotosensitising system based on a carefully designed porphyrin. The control of the photoactivities of the resulting supramolecular fibres lies in the spatiotemporal control of the monomer-polymer equilibrium. Both the thermodynamics and kinetics of this nanosystem have been carefully studied by different techniques. Moreover, in vitro and in vivo studies have also been performed, showing that these supramolecular aggregates exhibit facile cell internalisation and progressive disassembly after being endocyted by targeted cells, leading to activation of the photosensitising units and eventually cell death and tumour eradication under photoirradiation.

Spherical and rod shaped mesoporous silica nanoparticles for cancer-targeted and photosensitizer delivery in photodynamic therapy.

Mesoporous silica nanoparticles (MSNPs) have attracted much attention in many biomedical applications. One of the fields in which smart functional nanosystems have found wide application is cancer treatment. Here, we present new silica nanoparticle-based systems which have been explored as efficient vehicles to transport and deliver photosensitizers (PSs) into tumor tissues during photodynamic therapy (PDT). In this work, we report the preparation, characterization, and in vitro studies of distinct shaped MSNPs grafted with S-glycoside porphyrins (Pors). The ensuing nanomaterials were fully characterized, and their properties as third-generation PSs for PDT against two bladder cancer cell lines, HT-1376 and UM-UC-3, were examined. The best uptake results were obtained for MSNP-PS2, while MSNP-PS1 showed the lowest cellular uptake among the nanocarriers tested, but revealed the best phototoxicity in both cancer cells. Overall, the phototoxicity was higher with MSNPs than with mesoporous silica nanorods (MSNRs) and higher uptake and phototoxicity were consistently observed in UM-UC-3 rather than in HT-1376 cancer cells.

A self-assembled subphthalocyanine-based nanophotosensitiser for photodynamic therapy.

A subphthalocyanine substituted with nine tetra(ethylene glycol) chains on the periphery has been synthesised. This novel amphiphilic and cone-shaped compound can self-assemble in water into spherical nanoparticles with a hydrodynamic diameter of 154 nm. These nanoparticles can be taken up readily by cancer cells and localised predominately in lysosomes where they disassemble gradually, leading to activation in fluorescence emission and, photocytotoxicity, showing IC50 values of as low as 1.2 µM.

Subphthalocyanines as Efficient Photosensitizers with Nanomolar Photodynamic Activity against Cancer Cells.

Because cancer is the second leading cause of death globally, investigation of new photosensitizers for photodynamic therapy is highly desirable. In this work, different peripherally substituted subphthalocyanines (SubPcs) with either a benzocrown moiety (CE-) or a tyrosine methyl ester (Tyr-) as the axial ligand have been prepared. Target SubPcs showed high ΦΔ values, >0.50 in EtOH. Both CE- and Tyr- moieties increased substantially the hydrophilicity of the compounds (log P = 1.79-2.63, n-octanol/PBS). Uptake to cells, subcellular localization, and monitoring of the progression of cell death over time are described. Improved spectroscopic behavior of the CE- series in cell culture medium resulted in higher photodynamic activity versus that of the Tyr- series. In particular, the peripherally triethylsulfanyl SubPc-CE exhibited extraordinarily low EC50 values of 2.3 and 4.4 nM after light activation and high TC50 values of 14.49 and 5.25 µM (i.e., dark toxicity without activation) on SK-MEL-28 and HeLa cells, respectively, which rank it among the best photosensitizers ever.

Nanoparticles for Triple Drug Release for Combined Chemo- and Photodynamic Therapy.

A pH-responsive drug delivery system (DDS) based on mesoporous silica nanoparticles (MSNs) has been prepared for the delivery of three anticancer drugs with different modes of action. The novelty of this system is its ability to combine synergistic chemotherapy and photodynamic therapy. A photoactive conjugate of a phthalocyanine (Pc) and a topoisomerase I inhibitor (topo-I), namely camptothecin (CPT), linked by a poly(ethylene glycol) (PEG) chain has been synthesized and then loaded into the mesopores of MSNs. Doxorubicin (DOX), which is a topoisomerase II inhibitor (topo-II), has also been covalently anchored to the outer surface of the MSNs through a dihydrazide PEG linker. In the acidic environment of tumor cells, selective release of the three drugs takes place. In vitro studies have demonstrated the endocytosis of the system into HeLa and HepG2 cells, and the subsequent release of the three drugs into the cytoplasm and nucleus. Furthermore, the cytotoxic effect of DOX, CPT and Pc has been assessed in vitro before and upon light irradiation.

Photooxidation Responsive Elastin-Like Polypeptide Conjugates for Photodynamic Therapy Application.

Stimuli-responsive recombinant elastin-like polypeptides (ELPs) are artificial protein polymers derived from the hydrophobic domain of tropoelastin that have attracted significant interest for drug delivery and tissue engineering applications. In the present study, we have conjugated a photosensitizer (PS) to a hydrophobic methionine-containing ELP scaffold, which upon reaction with singlet oxygen (1O2) is transformed into a hydrophilic sulfoxide derivative facilitating the disassembly of photosensitizer-delivery particles during the photodynamic therapy (PDT) process. A peripherally substituted carboxy-Zn(II)-phthalocyanine derivative (TT1) bearing a carboxyl group directly linked to the Pc-ring, and presenting an absorption maximum around 680 nm, was selected as PS which simultaneously acted as a photooxidation catalyst. A TT1-ELP[M1V3-40] conjugate was prepared from ELP[M1V3-40] modified with an alkyne group at the N-terminal chain end, and from TT1-amide-C3-azide by copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) reaction. This innovative model photooxidation sensitive PS delivery technology offers promising attributes in terms of temperature-controlled particle formation and oxidation-triggered release, narrow molar mass distribution, reproducibility, scalability, non-immunogenicity, biocompatibility, and biodegradability for pharmaceutical applications in an effort to improve the clinical effectiveness of PDT treatments.

Self-Assembled Porphyrinoids: One-Component Nanostructured Photomedicines.

Photodynamic therapy (PDT) is becoming a promising way to treat various kinds of cancers, with few side effects. Porphyrinoids are the most relevant photosensitizers (PS) in PDT, because they present high extinction coefficients, biocompatibility, and excellent photochemical behavior. To maximize therapeutic effects, polymer-PS conjugates, and PS-loaded nanoparticles have been developed, with insights in improving tumor delivery. However, some drawbacks such as non-biodegradability, multistep fabrication, and low reagent loadings limit their clinical application. A novel strategy, noted by some authors as the "one-for-all" approach, is emerging to circumvent the use of additional delivery agents. This approach relies on the self-assembly of amphiphilic PS to fabricate nanostructures with improved transport properties. In this review we focus on different rational designs of porphyrinoid PS to achieve some of the following attributes in nanoassembly: i) selective uptake, through the incorporation of recognizable biological vectors; ii) responsiveness to stimuli; iii) combination of imaging and therapeutic functions; and iv) multimodal therapy, including photothermal or chemotherapy abilities.

Tuning the Nanoaggregates of Sialylated Biohybrid Photosensitizers for Intracellular Activation of the Photodynamic Response.

In the endeavor of extending the clinical use of photodynamic therapy (PDT) for the treatment of superficial cancers and other neoplastic diseases, deeper knowledge and control of the subcellular processes that determine the response of photosensitizers (PS) are needed. Recent strategies in this direction involve the use of activatable and nanostructured PS. Here, both capacities have been tuned in two dendritic zinc(II) phthalocyanine (ZnPc) derivatives, either asymmetrically or symmetrically substituted with 3 and 12 copies of the carbohydrate sialic acid (SA), respectively. Interestingly, the amphiphilic ZnPc-SA biohybrid (1) self-assembles into well-defined nanoaggregates in aqueous solution, facilitating cellular internalization and transport whereas the PS remains inactive. Within the cells, these nanostructured hybrids localize in the lysosomes, as usually happens for anionic and hydrophilic aggregated PS. Yet, in contrast to most of them (e. g., compound 2), hybrid 1 recovers the capacity for photoinduced ROS generation within the target organelles due to its amphiphilic character; this allows disruption of aggregation when the compound is inserted into the lysosomal membrane, with the concomitant highly efficient PDT response.

Peripherally Crowded Cationic Phthalocyanines as Efficient Photosensitizers for Photodynamic Therapy.

Photodynamic therapy is a treatment modality of cancer based on the production of cytotoxic species upon the light activation of photosensitizers. Zinc phthalocyanine photosensitizers bearing four or eight bulky 2,6-di(pyridin-3-yl)phenoxy substituents were synthesized, and pyridyl moieties were methylated. The quaternized derivatives did not aggregate at all in water and retained their good photophysical properties. High photodynamic activity of these phthalocyanines was demonstrated on HeLa, MCF-7, and EA.hy926 cells with a very low EC50 of 50 nM (for the MCF-7 cell line) upon light activation while maintaining low toxicity in the dark (TC50 ≈ 600 µM), giving thus good phototherapeutic indexes (TC50/EC50) above 1400. The compounds localized primarily in the lysosomes, leading to their rupture after light activation. This induced an apoptotic cell death pathway with secondary necrosis because of extensive and swift damage to the cells. This work demonstrates the importance of a bulky and rigid arrangement of peripheral substituents in the development of photosensitizers.

Highly Efficient Singlet Oxygen Generators Based on Ruthenium Phthalocyanines: Synthesis, Characterization and in vitro Evaluation for Photodynamic Therapy.

Invited for the cover of this issue is the group of Torres at the University of Madrid. The image of the cover of this issue depicts cancer cells being destroyed by reactive singlet oxygen produced by ruthenium phthalocyanine glycoconjugates under red light. The work, developed at the Universities of Madrid, Aveiro, Lisbon and Coimbra, describes ruthenium phthalocyanines as powerful bladder cancer PDT agents. Read the full text of the article at 10.1002/chem.201903546.

Assessing Amphiphilic ABAB Zn(II) Phthalocyanines with Enhanced Photosensitization Abilities in In Vitro Photodynamic Therapy Studies Against Cancer.

We have previously demonstrated that singlet oxygen photosensitization abilities of Zn(II) phthalocyanines (Zn(II)Pcs) are enhanced through α-functionalization with bulky fluorinated substituents (i.e., bis(trifluoromethyl)phenyl units) at facing positions of ABAB Zn(II)Pcs, where A and B refer to differently functionalized isoindoles. In this work, we have prepared the Zn(II)Pc ABAB 1 endowed with hydrophilic triethylene glycol monomethyl ether (i.e., at the A isoindoles) to provide solubility in aqueous media, together with its A3B and A4 counterparts, and compared their ability to behave as photosensitizers for photodynamic therapy. All photophysical data, aggregation studies and preliminary in vitro biological assays in cell cultures of SCC-13 (squamous cell carcinoma) and HeLa (cervical cancer cells), have proved ABAB 1 as the best photosensitizer of the series.

The unique features and promises of phthalocyanines as advanced photosensitisers for photodynamic therapy of cancer.

Phthalocyanines exhibit superior photoproperties that make them a surely attractive class of photosensitisers for photodynamic therapy of cancer. Several derivatives are at various phases of clinical trials, and efforts have been put continuously to improve their photodynamic efficacy. To this end, various strategies have been applied to develop advanced phthalocyanines with optimised photoproperties, dual therapeutic actions, tumour-targeting properties and/or specific activation at tumour sites. The advantageous properties and potential of phthalocyanines as advanced photosensitisers for photodynamic therapy of cancer are highlighted in this tutorial review.

Highly Efficient Singlet Oxygen Generators Based on Ruthenium Phthalocyanines: Synthesis, Characterization and in vitro Evaluation for Photodynamic Therapy.

The synthesis of ruthenium(II) phthalocyanines (RuPcs) endowed with one carbohydrate unit-that is, glucose, galactose and mannose-and a dimethylsulfoxide (DMSO) ligand at the two axial coordination sites, respectively, is described. Two series of compounds, one unsubstituted at the periphery, and the other one bearing eight PEG chains at the isoindole meta-positions, have been prepared. The presence of the axial DMSO unit significantly increases the phthalocyanine singlet oxygen quantum yields, related to other comparable RuPcs. The compounds have been evaluated for PDT treatment in bladder cancer cells. In vitro studies have revealed high phototoxicity for RuPcs unsubstituted at their periphery. The phototoxicity of PEG-substituted RuPcs has been considerably improved by repeated light irradiation. The choice of the axial carbohydrate introduced little differences in the cellular uptake for both series of photosensitizers, but the phototoxic effects were considerably higher for compounds bearing mannose units.

Phthalocyanine-Virus Nanofibers as Heterogeneous Catalysts for Continuous-Flow Photo-Oxidation Processes.

The generation of highly reactive oxygen species (ROS) at room temperature for application in organic synthesis and wastewater treatment represents a great challenge of the current chemical industry. In fact, the development of biodegradable scaffolds to support ROS-generating active sites is an important prerequisite for the production of environmentally benign catalysts. Herein, the electrostatic cocrystallization of a cationic phthalocyanine (Pc) and negatively charged tobacco mosaic virus (TMV) is described, together with the capacity of the resulting crystals to photogenerate ROS. To this end, a novel peripherally crowded zinc Pc (1) is synthesized. With 16 positive charges, this photosensitizer shows no aqueous aggregation, and is able to act as a molecular glue in the unidimensional assembly of TMV. A step-wise decrease of ionic strength in mixtures of both components results in exceptionally long fibers, constituted by hexagonally bundled viruses thoroughly characterized by electron and confocal microscopy. The fibers are able to produce ROS in a proof-of-concept microfluidic device, where they are immobilized and irradiated in several cycles, showing a resilient performance. The bottom-up approach also enables the light-triggered disassembly of fibers after use. This work represents an important example of a biohybrid material with projected application in light-mediated heterogeneous catalysis.

Prevalence of intraepithelial lesion in cervical screening cytology in a First-level Care Unit / Prevalencia de lesión intraepitelial en citología cervical de tamizaje en una unidad de primer nivel de atención

Background: Cervical cancer represents the second leading cause of malignant neoplasm mortality in women globally. Cervical cytology is the most important screening study. It is therefore of interest to know the prevalence of cytological alterations in the Mexican population. In this study the objective was to calculate the prevalence of intraepithelial lesion in cervical screening cytology. Methods: An observational, descriptive and cross-sectional study was developed; the sample was 379 patients from 21 to 64 years of age; we included patients who underwent cervical screening cytology registered in the Detección Oportuna de Cáncer Cervicouterino (DOC-CACU) program database. A descriptive analysis of the data was performed. Results: A prevalence of intraepithelial lesion of 4.49% was found. The 3.17% corresponded to LIEBG and 1.32% to LIEAG. No reports of invasive carcinoma were found. Of these patients, 64.71% corresponded to the age group from 41 to 60 years. 52.94% had had their last cytology in the previous 3 years or more and 35.29% were in postmenopause. Conclusions: A prevalence consistent with what was described in the literature was found. More than half of the affected patients had their last cytology in the previous 3 or more years and corresponded to the age group from 41 to 60 years. A high proportion of patients were in postmenopause.

Introducción: El cáncer cervicouterino representa la segunda causa de mortalidad por neoplasias malignas en la mujer a nivel mundial. La citología cervical es el estudio de tamizaje más importante. Por lo tanto, es de interés conocer la prevalencia de alteraciones citológicas en la población mexicana. En este estudio, el objetivo fue calcular la prevalencia de lesión intraepitelial en citología cervical de tamizaje. Métodos: Se elaboró un estudio observacional, descriptivo y transversal, con una muestra de 379 pacientes; se incluyeron pacientes de 21 a 64 años de edad, a las cuales se les realizó una citología cervical de tamizaje registradas en la base de datos del programa de Detección Oportuna de Cáncer Cervicouterino (DOC-CACU). Se realizó un análisis descriptivo de los datos. Resultados: Se encontró una prevalencia de lesión intraepitelial de 4.49%. El 3.17% correspondieron a LIEBG y el 1.32% a LIEAG. No se encontró ningún reporte de carcinoma invasor. De estas pacientes, el 64.71% correspondió al grupo etario de 41 a 60 años. El 52.94% se había realizado su última citología en los 3 años previos o más, y el 35.29% se encontraba en la posmenopausia. Conclusiones: Se encontró una prevalencia congruente con lo descrito en la literatura. Más de la mitad de las pacientes afectadas se realizaron su última citología en los 3 o más años previos y correspondían al grupo etario de 41 a 60 años. Una proporción alta de pacientes se encontraba en la posmenopausia.

Salt Cluster Attachment to Crown Ether Decorated Phthalocyanines in the Gas Phase.

Crown ether decorated phthalocyanines were designed to form rigidly eclipsed aggregates with metal ions being sandwiched between the molecules. We studied tetra-[18]crown-6 ether functionalized zinc phthalocyanine (ZnPcTetCr) in the presence of excess NaCl by electrospray ionization mass spectrometry. ZnPcTetCr was found to form aggregates in the gas phase to which several neutral NaCl molecules are attached. Collision-induced dissociation experiments revealed that the ions observed in the positive- and negative-ion modes possess remarkably different structures. Their fragmentation behavior indicates that the sodium ions providing the charge of the positively charged aggregates are strongly bound inside the crown ether moieties, while the neutral salt units are less strongly attached. However, in the negatively charged ions, none of the sodium ions is embedded in the crown ether moieties, and the NaCl molecules were found to be attached as one large, weakly bound cluster.

A Galactose Dendritic Silicon (IV) Phthalocyanine as a Photosensitizing Agent in Cancer Photodynamic Therapy.

Two protected galacto-dendritic units have been axially coordinated to the central ion of a silicon(IV) phthalocyanine to afford SiPcPGal4 containing four units of galactose per macrocycle. These biological moieties provided better solubility in aqueous medium and a sensitizer with higher absorption peaks at 680-690 nm. The photodynamic activity of SiPcPGal4 was evaluated against UM-UC-3 human bladder cancer cell line and the results were compared with the activity of the reported SiPcPGal2 and SiPc(OH)2 . SiPcPGal4 had a better uptake and it was a better toxicity inducer than SiPcPGal2 and SiPc(OH)2 owing to its four galactose units, protected by isopropylidene groups, which can act as targeted micelles.

Macrophage selective photodynamic therapy by meta-tetra(hydroxyphenyl)chlorin loaded polymeric micelles: A possible treatment for cardiovascular diseases.

Selective elimination of macrophages by photodynamic therapy (PDT) is a new and promising therapeutic modality for the reduction of atherosclerotic plaques. m-Tetra(hydroxyphenyl)chlorin (mTHPC, or Temoporfin) may be suitable as photosensitizer for this application, as it is currently used in the clinic for cancer PDT. In the present study, mTHPC was encapsulated in polymeric micelles based on benzyl-poly(ε-caprolactone)-b-methoxy poly(ethylene glycol) (Ben-PCL-mPEG) using a film hydration method, with loading capacity of 17%. Because of higher lipase activity in RAW264.7 macrophages than in C166 endothelial cells, the former cells degraded the polymers faster, resulting in faster photosensitizer release and higher in vitro photocytotoxicity of mTHPC-loaded micelles in those macrophages. However, we observed release of mTHPC from the micelles in 30min in blood plasma in vitro which explains the observed similar in vivo pharmacokinetics of the mTHPC micellar formulation and free mTHPC. Therefore, we could not translate the beneficial macrophage selectivity from in vitro to in vivo. Nevertheless, we observed accumulation of mTHPC in atherosclerotic lesions of mice aorta's which is probably the result of binding to lipoproteins upon release from the micelles. Therefore, future experiments will be dedicated to increase the stability and thus allow accumulation of intact mTHPC-loaded Ben-PCL-mPEG micelles to macrophages of atherosclerotic lesions.