A cell-targeted photodynamic nanomedicine strategy for head and neck cancers

Graphene-Based Photodynamic Therapy and Overcoming Cancer Resistance Mechanisms: A Comprehensive Review

Photodynamic therapy (PDT) is a non-invasive therapy that has made significant progress in treating different diseases, including cancer, by utilizing new nanotechnology products such as graphene and its derivatives. Graphene-based materials have large surface area and photothermal effects thereby making them suitable candidates for PDT or photo-active drug carriers. The remarkable photophysical properties of graphene derivates facilitate the efficient generation of reactive oxygen species (ROS) upon light irradiation, which destroys cancer cells. Surface functionalization of graphene and its materials can also enhance their biocompatibility and anticancer activity. The paper delves into the distinct roles played by graphene-based materials in PDT such as photosensitizers (PS) and drug carriers while at the same time considers how these materials could be used to circumvent cancer resistance. This will provide readers with an extensive discussion of various pathways contributing to PDT inefficiency. Consequently, this comprehensive review underscores the vital roles that graphene and its derivatives may play in emerging PDT strategies for cancer treatment and other medical purposes. With a better comprehension of the current state of research and the existing challenges, the integration of graphene-based materials in PDT holds great promise for developing targeted, effective, and personalized cancer treatments.

The current status of nanotechnological approaches to therapy and drug delivery in otolaryngology: A contemporary review

Objectives/Hypothesis

To summarize the current standing of nanomedicine-based technology, particularly nanoparticles (NPs), for drug delivery and diagnostic mechanisms in otolaryngology and the otolaryngology subspecialties.

Methods

Literature searches were performed using PubMed and Ovid MEDLINE from 2010 to 2022. The search focused on original articles describing developments and applications of nanotechnology and drug delivery in otology, neurotology, cranial base surgery, head and neck oncology, laryngology, bronchoesophagology, and rhinology. Keyword searches and cross-referencing were also performed. No statistical analysis was performed.

Results

The PubMed search yielded 29 articles, and two Ovid MEDLINE searches both yielded 7 and 26 articles, respectively. Cross-referencing and keyword searches in PubMed and Google Scholar yielded numerous articles. The results indicate that currently, NPs are the most thoroughly studied nanotechnology for drug delivery and therapy in otolaryngology. Organic NPs have been utilized for drug delivery in otology and head and neck oncology due to their high biocompatibility. Inorganic NPs have similarly been utilized for drug delivery. However, inorganic NPs seem to be studied less extensively in these fields, likely due to an increased risk for heavy metal toxicity. Due to their magnetic properties, inorganic NPs have been utilized for magnetic-guided delivery in otology and thermoradiation and magnetic resonance imaging in head and neck oncology. Applications of nanotechnology to the fields of laryngology, bronchoesophagology, and rhinology have been studied less compared with otology and head and neck oncology. However, researchers have primarily employed NPs and other nanotechnologies such as nanofibers and nanoclusters for drug elution at mucosal surfaces to reduce airway and nasal inflammation.

Conclusions

Nanomedicine offers potential benefits in the treatment of patients in the field of otolaryngology due to enhanced control over drug release, cell-specific targeting, and the potential to reduce drug toxicity. Future work is needed to ensure the safety of these therapies to integrate this field of research into human therapies.

Advances in Photodynamic Therapy Based on Nanotechnology and Its Application in Skin Cancer

Comprehensive cancer treatments have been widely studied. Traditional treatment methods (e.g., radiotherapy, chemotherapy), despite ablating tumors, inevitably damage normal cells and cause serious complications. Photodynamic therapy (PDT), with its low rate of trauma, accurate targeting, synergism, repeatability, has displayed great advantages in the treatment of tumors. In recent years, nanotech-based PDT has provided a new modality for cancer treatment. Direct modification of PSs by nanotechnology or the delivery of PSs by nanocarriers can improve their targeting, specificity, and PDT efficacy for tumors. In this review, we strive to provide the reader with a comprehensive overview, on various aspects of the types, characteristics, and research progress of photosensitizers and nanomaterials used in PDT. And the application progress and relative limitations of nanotech-PDT in non-melanoma skin cancer and melanoma are also summarized.

Photodynamic therapy associated with nanomedicine strategies for treatment of human squamous cell carcinoma: A systematic review and meta-analysis

A systematic review and meta-analysis were conducted about photodynamic therapy (PDT) associated with nanomedicine approaches in the treatment of human squamous cell carcinoma (HSSC). Independent reviewers conducted all steps in the systematic review. For evaluating the risk of bias, RoB 2, OHAT and SYRCLE tools were used. Meta-analysis was performed using a random-effect model (α = 0.05). For PDT against HSSC, Protoporphyrin IX was the photosensitizer, and liposomes were the nanomaterial more frequently used. Photosensitizers conjugated with nanoparticles exhibited positive results against HSSC. Tumors treated with PDT in combination with a nanotechnology drug-delivery system had an increased capacity for inhibiting the tumor growth rate (51.93%/P < 0.0001) when compared with PDT only. Thus, the PDT associated with nanomedicine approaches against HSCC could be a significant option for use in future clinical studies, particularly due to improved results in tumor growth inhibition.

EGFR-Targeted Photodynamic Therapy

The epidermal growth factor receptor (EGFR) plays a pivotal role in the proliferation and metastatization of cancer cells. Aberrancies in the expression and activation of EGFR are hallmarks of many human malignancies. As such, EGFR-targeted therapies hold significant potential for the cure of cancers. In recent years, photodynamic therapy (PDT) has gained increased interest as a non-invasive cancer treatment. In PDT, a photosensitizer is excited by light to produce reactive oxygen species, resulting in local cytotoxicity. One of the critical aspects of PDT is to selectively transport enough photosensitizers to the tumors environment. Accordingly, an increasing number of strategies have been devised to foster EGFR-targeted PDT. Herein, we review the recent nanobiotechnological advancements that combine the promise of PDT with EGFR-targeted molecular cancer therapy. We recapitulate the chemistry of the sensitizers and their modes of action in PDT, and summarize the advantages and pitfalls of different targeting moieties, highlighting future perspectives for EGFR-targeted photodynamic treatment of cancer.

Quantitative Photothermal Characterization with Bioprinted 3D Complex Tissue Constructs for Early-Stage Breast Cancer Therapy Using Gold Nanorods

Plasmonic photothermal therapy (PPTT) using gold nanoparticles (AuNPs) has shown great potential for use in selective tumor treatment, because the AuNPs can generate destructive heat preferentially upon irradiation. However, PPTT using AuNPs has not been added to practice, owing to insufficient heating methods and tissue temperature measurement techniques, leading to unreliable and inaccurate treatments. Because the photothermal properties of AuNPs vary with laser power, particle optical density, and tissue depth, the accurate prediction of heat generation is indispensable for clinical treatment. In this report, bioprinted 3D complex tissue constructs comprising processed gel obtained from porcine skin and human decellularized adipose tissue are presented for characterization of the photothermal properties of gold nanorods (AuNRs) having an aspect ratio of 3.7 irradiated by a near-infrared laser. Moreover, an analytical function is suggested for achieving PPTT that can cause thermal damage selectively on early-stage human breast cancer by regulating the heat generation of the AuNRs in the tissue.

Radiolabeled Peptide Probes for Liver Cancer Imaging

Liver cancer/Hepatocellular Carcinoma (HCC) is a leading cause of cancer death and represents an important cause of mortality worldwide. Several biomarkers are overexpressed in liver cancer, such as Glypican 3 (GPC3) and Epidermal Growth Factor Receptor (EGFR). These biomarkers play important roles in the progression of tumors and could serve as imaging and therapeutic targets for this disease. Peptides with adequate stability, receptor binding properties, and biokinetic behavior have been intensively studied for liver cancer imaging. A great variety of them have been radiolabeled with clinically relevant radionuclides for liver cancer diagnosis, and many are promising imaging and therapeutic candidates for clinical translation. Herein, we summarize the advancement of radiolabeled peptides for the targeted imaging of liver cancer.

Ligand-Targeted Delivery of Photosensitizers for Cancer Treatment

Photodynamic therapy (PDT) is a promising cancer treatment which involves a photosensitizer (PS), light at a specific wavelength for PS activation and oxygen, which combine to elicit cell death. While the illumination required to activate a PS imparts a certain amount of selectivity to PDT treatments, poor tumor accumulation and cell internalization are still inherent properties of most intravenously administered PSs. As a result, common consequences of PDT include skin photosensitivity. To overcome the mentioned issues, PSs may be tailored to specifically target overexpressed biomarkers of tumors. This active targeting can be achieved by direct conjugation of the PS to a ligand with enhanced affinity for a target overexpressed on cancer cells and/or other cells of the tumor microenvironment. Alternatively, PSs may be incorporated into ligand-targeted nanocarriers, which may also encompass multi-functionalities, including diagnosis and therapy. In this review, we highlight the major advances in active targeting of PSs, either by means of ligand-derived bioconjugates or by exploiting ligand-targeting nanocarriers.

Patient-Derived Head and Neck Cancer Organoids Recapitulate EGFR Expression Levels of Respective Tissues and Are Responsive to EGFR-Targeted Photodynamic Therapy

Patients diagnosed with head and neck squamous cell carcinoma (HNSCC) are currently treated with surgery and/or radio- and chemotherapy. Despite these therapeutic interventions, 40% of patients relapse, urging the need for more effective therapies. In photodynamic therapy (PDT), a light-activated photosensitizer produces reactive oxygen species that ultimately lead to cell death. Targeted PDT, using a photosensitizer conjugated to tumor-targeting molecules, has been explored as a more selective cancer therapy. Organoids are self-organizing three-dimensional structures that can be grown from both normal and tumor patient-material and have recently shown translational potential. Here, we explore the potential of a recently described HNSCC–organoid model to evaluate Epidermal Growth Factor Receptor (EGFR)-targeted PDT, through either antibody- or nanobody-photosensitizer conjugates. We find that EGFR expression levels differ between organoids derived from different donors, and recapitulate EGFR expression levels of patient material. EGFR expression levels were found to correlate with the response to EGFR-targeted PDT. Importantly, organoids grown from surrounding normal tissues showed lower EGFR expression levels than their tumor counterparts, and were not affected by the treatment. In general, nanobody-targeted PDT was more effective than antibody-targeted PDT. Taken together, patient-derived HNSCC organoids are a useful 3D model for testing in vitro targeted PDT.

Exploring pitfalls of 64Cu-labeled EGFR-targeting peptide GE11 as a potential PET tracer

The epidermal growth factor receptor (EGFR) represents an important molecular target for both radiotracer-based diagnostic imaging and radionuclide therapy of various cancer entities. For the delivery of radionuclides to the tumor, peptides hold great potential as a transport vehicle. With respect to EGFR, the peptide YHWYGYTPQNVI (GE11) has been reported to bind the receptor with high specificity and affinity. In the present study, GE11 with β-alanine (β-Ala-GE11) was conjugated to the chelating agent p-SCN-Bn-NOTA and radiolabeled with ⁶⁴Cu for the first radio pharmacological evaluation as a potential probe for positron emission tomography (PET)-based cancer imaging. For better water solubility, an ethylene glycol-based linker was introduced between the peptide's N terminus and the radionuclide chelator. The stability of the ⁶⁴Cu-labeled peptide conjugate and its binding to EGFR-expressing tumor cells was investigated in vitro and in vivo, and then compared with the ⁶⁴Cu-labeled EGFR-targeting antibody conjugate NOTA-cetuximab. The GE11 peptide conjugate [⁶⁴Cu]Cu-NOTA-linker-β-Ala-GE11 ([⁶⁴Cu]Cu-1) was stable in a buffer solution for at least 24 h but only 50% of the original compound was detected after 24 h of incubation in human serum. Stability could be improved by amidation of the peptide's C terminus (β-Ala-GE11-NH₂ (2)). Binding assays with both conjugates, [⁶⁴Cu]Cu-1 and [⁶⁴Cu]Cu-2, using the EGFR-expressing tumor cell lines A431 and FaDu showed no specific binding. A pilot small animal PET investigation in FaDu tumor-bearing mice revealed only low tumor uptake (standard uptake value (SUV) < 0.2) for both conjugates. The best tumor-to-muscle ratio determined was 3.75 for [⁶⁴Cu]Cu-1, at 1 h post injection. In conclusion, the GE11 conjugates in its present form are not suitable for further biological investigations, since they presumably form aggregates.

Intracellular GSH-activated galactoside photosensitizers for targeted photodynamic therapy and chemotherapy

Ligand-targeted cancer therapeutics has been developed to minimize non-specific cytotoxicity via ligand-drug conjugates during the past few decades. We present here the design and synthesis of a GSH-activated amphiphilic photosensitizer conjugated with galactose (TPP-S-S-Gal) for targeted photodynamic therapy. Furthermore, the galactoside photosensitizer as supramolecular amphiphiles can self-assemble into micelles, which can be applied in integrative cancer treatment with chemotherapy drugs such as camptothecin (CPT) encapsulated in the hydrophobic core of micelles. Upon reaction with free thiol GSH that is relatively abundant in tumor cells, disulfide bond cleavage occurs as well as the active photosensitizer TPP and chemotherapy drug CPT release, which can cause cell apoptosis. The in vitro biological assessment of TPP-S-S-Gal micelles against the A549 cell line was evaluated by MTT assay, flow cytometry and confocal scanning laser microscopy, respectively. According to the MTT assay, TPP-S-S-Gal micelles exhibited low dark toxicity and efficient integrative efficacy of PDT and chemotherapy towards A549 cells after light irradiation.

Local hyperthermia in head and neck cancer: mechanism, application and advance

Local hyperthermia (HT), particularly in conjunction with surgery, radiotherapy and chemotherapy was useful for the treatment of human malignant tumors including head and neck cancer. However, at present it suffered from many limitations such as thermal dose control, target treatment regions and discrimination between healthy and cancer cells. Recent developments in nanotechnology have introduced novel and smart therapeutic nanomaterials to local HT of head and neck cancer that basically take advantage of various targeting approaches. The aim of this paper is to give a brief review of the mechanism, methods and clinical applications of local HT in head and neck cancer, mainly focusing on photothermal therapy (PTT) and nanoparticle-based hyperthermia.

GE11 Peptide as an Active Targeting Agent in Antitumor Therapy: A Minireview

A lot of solid tumors are characterized by uncontrolled signal transduction triggered by receptors related to cellular growth. The targeting of these cell receptors with antitumor drugs is essential to improve chemotherapy efficacy. This can be achieved by conjugation of an active targeting agent to the polymer portion of a colloidal drug delivery system loaded with an antitumor drug. The goal of this minireview is to report and discuss some recent results in epidermal growth factor receptor targeting by the GE11 peptide combined with colloidal drug delivery systems as smart carriers for antitumor drugs. The minireview chapters will focus on explaining and discussing: (i) Epidermal growth factor receptor (EGFR) structures and functions; (ii) GE11 structure and biologic activity; (iii) examples of GE11 conjugation and GE11-conjugated drug delivery systems. The rationale is to contribute in gathering information on the topic of active targeting to tumors. A case study is introduced, involving research on tumor cell targeting by the GE11 peptide combined with polymer nanoparticles.

GE11 peptide-conjugated nanoliposomes to enhance the combinational therapeutic efficacy of docetaxel and siRNA in laryngeal cancers

In this study, dual therapeutic-loaded GE11 peptide-conjugated liposomes were developed and applied to enhance therapeutic efficacies of standard-of-care regimens for the treatment of laryngeal cancer. The therapeutic strategy used here was a combination treatment with the chemotherapeutic docetaxel (DTX) and siRNA against the ABCG2 gene that regulates multidrug resistance in many tumor types. Liposome-encapsulated DTX/ABCG2-siRNA molecules were targeted to recognize tumor cells of squamous morphology by conjugation to the EGFR-targeting ligand, GE11. Targeted, drug-infused liposomes were nanosized and exhibited controlled release of DTX. Presence of GE11 peptides on liposomal surfaces enhanced the quantities of liposomal constructs taken up by Hep-2 laryngeal cancer cells. GE11 peptide-conjugated liposomes also enhanced cytotoxic effects against Hep-2 laryngeal cancer cells when compared to treatment with free DTX, thereby reducing IC50 values. Additionally, GE11 peptide-conjugated liposomes had significantly increased anti-tumor and apoptotic effects. Treatments with the GDSL nanoparticle formulation inhibited tumor growth in Hep-2 xenograft-bearing nude mouse models when compared to treatments with non-targeted NP constructs. Treatment of the mouse models with GE11 peptide-conjugated liposomes mitigated toxicities observed after treatment with free DTX. Taken together, liposomal encapsulation of DTX and ABCG2-siRNA improved the anti-tumor effects of treatment with free DTX in Hep-2 cell lines, and conjugation of GE11 peptides to liposomal constructs enhanced anti-tumor efficacies and specificities in laryngeal cancer cells.

99mTc-radiolabeled GE11-modified peptide for ovarian tumor targeting

Background

Ovarian cancer is a serious threat for women health and the early diagnosis of this cancer might improves the survival rate of patients. The use of the targeted radiopharmaceuticals could be a non-invasive and logical method for tumor imaging. The aim of this study was to radiolabel GE11 peptide as a new specific probe for imaging of ovarian tumor.

Methods

HYNIC-SSS-GE11 peptide was labeled with ^99mTc using tricine as a coligand. The ^99mTc-tricine-HYNIC-SSS-GE11 peptide was evaluated for specific cellular binding in three cell lines with different levels of EGFR expression. Tumor targeting was assessed in SKOV3 tumor bearing mice.

Results

By using tricine as a coligand, labeling yield was more than 98% and the stability of the radiolabelled peptide in human serum up to 4 h was 96%. The in vitro cell uptake test showed that this radiolabeled peptide had a good affinity to SKOV3 cells with dissociation constant of 73 nM. The in vivo results showed a tumor/muscle ratio of 3.2 at 4 h following injection of ^99mTc-tricine-HYNIC-SSS-GE11 peptide.

Conclusions

Results of this study showed that ^99mTc-tricine-HYNIC-SSS-GE11 peptide could be a promising tool for diagnosis and staging of ovarian cancer.

Graphical Abstract

^99mTc-tricine-HYNIC-SSS-GE11, a novl targeted agent for ovarian tumor imaging

Multilayer photodynamic therapy for highly effective and safe cancer treatment

Recent efforts to develop tumor-targeted photodynamic therapy (PDT) photosensitizers (PSs) have greatly advanced the potential of PDT in cancer therapy, although complete eradication of tumor cells by PDT alone remains challenging. As a way to improve PDT efficacy, we report a new combinatory PDT therapy technique that specifically targets multilayers of cells. Simply mixing different PDT PSs, even those that target distinct receptors (this may still lead to similar cell-killing pathways), may not achieve ideal therapeutic outcomes. Instead, significantly improved outcomes likely require synergistic therapies that target various cellular pathways. In this study, we target two proteins upregulated in cancers: the cannabinoid CB2 receptor (CB₂R, a G-protein coupled receptor) and translocator protein (TSPO, a mitochondria membrane receptor). We found that the CB₂R-targeted PS, IR700DX-mbc94, triggered necrotic cell death upon light irradiation, whereas PDT with the TSPO-targeted IR700DX-6T agent led to apoptotic cell death. Both PSs significantly inhibited tumor growth in vivo in a target-specific manner. As expected, the combined CB₂R- and TSPO-PDT resulted in enhanced cell killing efficacy and tumor inhibition with lower drug dose. The median survival time of animals with multilayer PDT treatment was extended by as much as 2.8-fold over single PDT treatment. Overall, multilayer PDT provides new opportunities to treat cancers with high efficacy and low side effects.

STATEMENT OF SIGNIFICANCE

Photodynamic therapy (PDT) is increasingly used as a minimally invasive, controllable and effective therapeutic procedure for cancer treatment. However, complete eradication of tumor cells by PDT alone remains challenging. In this study, we investigate the potential of multilayer PDT in cancer treatment with high efficacy and low side effects. Through PDT targeting two cancer biomarkers located at distinct subcellular localizations, remarkable synergistic effects in cancer cell killing and tumor inhibition were observed in both in vitro and in vivo experiments. This strategy may be widely applied to treat various cancer types by using strategically designed PDT photosensitizers that target corresponding upregulated receptors at tactical subcellular localization.

Doxorubicin-Loaded Photosensitizer-Core pH-Responsive Copolymer Nanocarriers for Combining Photodynamic Therapy and Chemotherapy

Photodynamic therapy (PDT) is an emerging method for the treatment of cancer. Combination of PDT and chemotherapy is a hot topic though the two therapies could not simultaneously exert their perfect effect in vivo. Here we report a doxorubicin-loaded photosensitizer-core pH-responsive copolymer nanocarrier with high tumor targeting and anticancer effects due to integration of PDT with chemotherapy. The pH-responsive photosensitizer-core four-armed star-shaped copolymer, [methoxy-poly(ethylene glycol)-poly(2-(N,N-diethylamino)ethyl methacrylate)-poly(ε-caprolactone)]₄-zinc β-tetra-(4-carboxyl benzyloxyl)phthalocyanine (PDCZP), was prepared, which was a molecular spherical nanocarrier in aqueous media. The carriers changed from small at high pH to large at low pH (51, 105, and 342 nm at pH 7.4, 6.5, and 5.0, respectively) and the zeta potential gradually increased (7.15, 16.2, and 26.1 mV at the above pH, respectively). PDCZP had a longer emission wavelength (max. 677 nm) than the parent photosensitizer, favoring light penetration through biological tissues. The singlet oxygen (¹O₂) quantum yield of PDCZP was 0.41. Doxorubicin (DOX) showed rapid release from PDCZP in the acidic media. More importantly, the drug-loaded nanocarriers showed the better in vitro and in vivo anticancer effects under lighting on MCF-7, SW480 cells and HepG2 cells and the murine hepatocellular carcinoma H₂₂ models than the other groups. PDCZP showed a high tumor targeting effect based on the enhanced permeation and retention effect and its small size. The photosensitizer-core nanocarrier is a promising photodynamic nanocarrier for integrating other therapies.

Synthesis and spectral evaluation of 5,10,15,20-tetrakis(3,4-dibenzyloxyphenyl)porphyrin

Porphyrins are of interest in many applications that involve electron transfer and absorption of light, such as solar energy and photodynamic cancer therapy. The newly synthesized 5,10,15,20-tetrakis(3,4-dibenzyloxyphenyl)porphyrin, TDBOPP, was characterized using 1H NMR, 13C NMR, UV-vis and fluorescence spectroscopy and MALDI-TOF/TOF high resolution mass spectrometry. Standard 1H NMR and 13C NMR experiments coupled with nuclear Overhauser effect (NOE) experiments confirmed the structure of the compound. The expected M+ and [M+H]+ ions are observed in the MALDI-TOF/TOF mass spectrum. The UV-vis absorption spectrum of TDBOPP shows a Soret band at 424 nm and three Q bands at 519 nm, 556 nm, and 650 nm with molar absorptivity 3.6×105 cm−1m−1, 1.6×104 cm−1m−1, 1.0×104 cm−1m−1 and 5.3×103 cm−1m−1, respectively. Excitation at 424 nm gives emission at 650 nm. The quantum yield of the porphyrin is 0.11.

Oncologic Photodynamic Therapy: Basic Principles, Current Clinical Status and Future Directions

Photodynamic therapy (PDT) is a clinically approved cancer therapy, based on a photochemical reaction between a light activatable molecule or photosensitizer, light, and molecular oxygen. When these three harmless components are present together, reactive oxygen species are formed. These can directly damage cells and/or vasculature, and induce inflammatory and immune responses. PDT is a two-stage procedure, which starts with photosensitizer administration followed by a locally directed light exposure, with the aim of confined tumor destruction. Since its regulatory approval, over 30 years ago, PDT has been the subject of numerous studies and has proven to be an effective form of cancer therapy. This review provides an overview of the clinical trials conducted over the last 10 years, illustrating how PDT is applied in the clinic today. Furthermore, examples from ongoing clinical trials and the most recent preclinical studies are presented, to show the directions, in which PDT is headed, in the near and distant future. Despite the clinical success reported, PDT is still currently underutilized in the clinic. We also discuss the factors that hamper the exploration of this effective therapy and what should be changed to render it a more effective and more widely available option for patients.

Photo-Cross-Linkable Polymer Dots with Stable Sensitizer Loading and Amplified Singlet Oxygen Generation for Photodynamic Therapy

Photodynamic therapy (PDT) is a promising treatment modality for clinical cancer therapy. However, the therapeutic effect of PDT is strongly dependent on the property of photosensitizer. Here, we developed photo-cross-linkable semiconductor polymer dots doped with photosensitizer Chlorin e6 (Ce6) to construct a nanoparticle platform for photodynamic therapy. Photoreactive oxetane groups were attached to the side chains of the semiconductor polymer. After photo-cross-linking reaction, the Ce6-doped Pdots formed an interpenetrated structure to prevent Ce6 leaching out from the Pdot matrix. Spectroscopic characterizations revealed an efficient energy transfer from the polymer to Ce6 molecules, resulting in amplified generation of singlet oxygen. We evaluated the cellular uptake, cytotoxicity, and photodynamic effect of the Pdots in gastric adenocarcinoma cells. In vitro photodynamic experiments indicated that the Ce6-doped Pdots (∼10 μg/mL) effectively killed the cancer cells under low dose of light irradiation (∼60 J/cm²). Furthermore, in vivo photodynamic experiments were carried out in tumor-bearing nude mice, which indicated that the Pdot photosensitizer apparently suppressed the growth of solid tumors. Our results demonstrate that the photo-cross-linkable Pdots doped with photosensitizer are promising for photodynamic cancer treatment.

One-Pot Aqueous Synthesization of Near-Infrared Quantum Dots for Bioimaging and Photodynamic Therapy of Gliomas

BACKGROUND

As the early detection and total destruction of gliomas are essential for longer survival, we attempted to synthesize a quantum dot (QD) that is capable of recognizing glioma cells for imaging and photodynamic therapy.

METHODS

Using a one-pot aqueous approach, near infrared-emitting CdTe was produced. After detection of its physicochemical characteriistics, it was conjugated with RGD. The emission images were observed with confocal microscopy. To test its toxicity, CdTe-RGD at various concentrations was separately added to a human glioma cell line (U251) and a mouse embryo fibroblast cell line (3T3) (control) for incubation in dark conditions. To test its photodynamic effect, the U251 and 3T3 cells were then irradiated for 5-60 min, using a 632.8-nm laser.

RESULTS

This QD (Φ = 3.75 nm, photoluminescence (PL) peak wavelength = 700 nm, photoluminescence quantum yield (PLQY) = 20 %), was a spherical crystal with excellent monodispersity. Under a confocal microscope, U251 cells were visualized, but not the 3T3 cells. In dark conditions, the survival rates of both U251 and 3T3 cells were above 85 %. After laser irradiation, the survival rate of U251 cells decreased to 37 ± 1.6 % as the irradiation time and the CdTe-RGD concentration were increased.

CONCLUSIONS

With good physicochemical characteriistics and low toxicity, this QD-RGD has broad prospects for use in the biomedical imaging and photodynamic therapy of gliomas.

Evaluation of Silicon Phthalocyanine 4 Photodynamic Therapy Against Human Cervical Cancer Cells In Vitro and in Mice

BACKGROUND

Cervical cancer is the second most common cancer in women worldwide [1]. Photodynamic therapy has been used for cervical intraepithelial neoplasia with good responses, but few studies have used newer phototherapeutics. We evaluated the effectiveness of photodynamic therapy using Pc 4 in vitro and in vivo against human cervical cancer cells.

METHODS

CaSki and ME-180 cancer cells were grown as monolayers and spheroids. Cell growth and cytotoxicity were measured using a methylthiazol tetrazolium assay. Pc 4 cellular uptake and intracellular distrubtion were determined. For in vitro Pc 4 photodynamic therapy cells were irradiated at 667nm at a fluence of 2.5 J/cm² at 48 h. SCID mice were implanted with CaSki and ME-180 cells both subcutaneously and intracervically. Forty-eight h after Pc 4 photodynamic therapy was administered at 75 and 150 J/cm².

RESULTS

The IC₅₀s for Pc 4 and Pc 4 photodynamic therapy for CaSki and ME-180 cells as monolayers were, 7.6μM and 0.016μM and >10μM and 0.026μM; as spheroids, IC₅₀s of Pc 4 photodynamic therapy were, 0.26μM and 0.01μM. Pc 4 was taken up within cells and widely distributed in tumors and tissues. Intracervical photodynamic therapy resulted in tumor death, however mice died due to gastrointestinal toxicity. Photodynamic therapy resulted in subcutaneous tumor death and growth delay.

CONCLUSIONS

Pc 4 photodynamic therapy caused death within cervical cancer cells and xenografts, supporting development of Pc 4 photodynamic therapy for treatment of cervical cancer. Support: P30-CA47904, CTSI BaCCoR Pilot Program.

A Multifunctional Biomaterial with NIR Long Persistent Phosphorescence, Photothermal Response and Magnetism

There are many reports on long persistent phosphors (LPPs) applied in bioimaging. However, there are few reports on LPPs applied in photothermal therapy (PTT), and an integrated system with multiple functions of diagnosis and therapy. In this work, we fabricate effective multifunctional phosphors Zn3 Ga2 SnO8 : Cr(3+) , Nd(3+) , Gd(3+) with NIR persistent phosphorescence, photothermal response and magnetism. Such featured materials can act as NIR optical biolabels and magnetic resonance imaging (MRI) contrast agents for tracking the early cancer cells, but also as photothermal therapeutic agent for killing the cancer cells. This new multifunctional biomaterial is expected to open a new possibility of setting up an advanced imaging-guided therapy system featuring a high resolution for bioimaging and low side effects for the photothermal ablation of tumors.

Enhanced In Vivo Tumor Detection by Active Tumor Cell Targeting Using Multiple Tumor Receptor-Binding Peptides Presented on Genetically Engineered Human Ferritin Nanoparticles

Human ferritin heavy-chain nanoparticle (hFTH) is genetically engineered to present tumor receptor-binding peptides (affibody and/or RGD-derived cyclic peptides, named 4CRGD here) on its surface. The affibody and 4CRGD specifically and strongly binds to human epidermal growth factor receptor I (EGFR) and human integrin αvβ3, respectively, which are overexpressed on various tumor cells. Through in vitro culture of EGFR-overexpressing adenocarcinoma (MDA-MB-468) and integrin-overexpressing glioblastoma cells (U87MG), it is clarified that specific interactions between receptors on tumor cells and receptor-binding peptides on engineered hFTH is critical in active tumor cell targeting. After labeling with the near-infrared fluorescence dye (Cy5.5) and intravenouse injection into MDA-MB-468 or U87MG tumor-bearing mice, the recombinant hFTHs presenting either peptide or both of affibody and 4CRGD are successfully delivered to and retained in the tumor for a prolonged period of time. In particular, the recombinant hFTH presenting both affibody and 4CRGD notably enhances in vivo detection of U87MG tumors that express heterogeneous receptors, integrin and EGFR, compared to the other recombinant hFTHs presenting either affibody or 4CRGD only. Like affibody and 4CRGD used in this study, other multiple tumor receptor-binding peptides can be also genetically introduced to the hFTH surface for actively targeting of in vivo tumors with heterogenous receptors.

Polymeric Nanoparticles for Cancer Photodynamic Therapy

In chemotherapy a fine balance between therapeutic and toxic effects needs to be found for each patient, adapting standard combination protocols each time. Nanotherapeutics has been introduced into clinical practice for treating tumors with the aim of improving the therapeutic outcome of conventional therapies and of alleviating their toxicity and overcoming multidrug resistance. Photodynamic therapy (PDT) is a clinically approved, minimally invasive procedure emerging in cancer treatment. It involves the administration of a photosensitizer (PS) which, under light irradiation and in the presence of molecular oxygen, produces cytotoxic species. Unfortunately, most PSs lack specificity for tumor cells and are poorly soluble in aqueous media, where they can form aggregates with low photoactivity. Nanotechnological approaches in PDT (nanoPDT) can offer a valid option to deliver PSs in the body and to solve at least some of these issues. Currently, polymeric nanoparticles (NPs) are emerging as nanoPDT system because their features (size, surface properties, and release rate) can be readily manipulated by selecting appropriate materials in a vast range of possible candidates commercially available and by synthesizing novel tailor-made materials. Delivery of PSs through NPs offers a great opportunity to overcome PDT drawbacks based on the concept that a nanocarrier can drive therapeutic concentrations of PS to the tumor cells without generating any harmful effect in non-target tissues. Furthermore, carriers for nanoPDT can surmount solubility issues and the tendency of PS to aggregate, which can severely affect photophysical, chemical, and biological properties. Finally, multimodal NPs carrying different drugs/bioactive species with complementary mechanisms of cancer cell killing and incorporating an imaging agent can be developed. In the following, we describe the principles of PDT use in cancer and the pillars of rational design of nanoPDT carriers dictated by tumor and PS features. Then we illustrate the main nanoPDT systems demonstrating potential in preclinical models together with emerging concepts for their advanced design.

An acid-cleavable phthalocyanine tetramer as an activatable photosensitiser for photodynamic therapy

A novel self-quenched phthalocyanine tetramer has been prepared which can be activated in acidic environments, resulting in enhanced fluorescence emission and singlet oxygen production.

Potential of porous silicon nanoparticles as an emerging platform for cancer theranostics

Currently, nanoscience is a major part of biomedical research, due to material advances that aid the development of new tools and techniques to replace traditional methods. Here we describe the theranostic potential of multifunctional porous silicon nanoparticles to target, image and treat cancer.

Mitochondrially Targeted Nanoparticles Based on α-TOS for the Selective Cancer Treatment

The aim of this work is the preparation of an active nanovehicle for the effective administration of α-tocopheryl succinate (α-TOS). α-TOS is loaded in the core of nanoparticles (NPs) based on amphiphilic pseudo-block copolymers of N-vinyl pyrrolidone and a methacrylic derivative of α-TOS. These well-defined spherical NPs have sizes below 165 nm and high encapsulation efficiencies. In vitro activity of NPs is tested in hypopharynx squamous carcinoma (FaDu) cells and nonmalignant epithelial cells, demonstrating that the presence of additional α-TOS significantly enhances its antiproliferative activity; however, a range of selective concentrations is observed. These NPs induce apoptosis of FaDu cells by activating the mitochondria death pathway (via caspase-9). Both loaded and unloaded NPs act via complex II and produce high levels of reactive oxygen species that trigger apoptosis. Additionally, these NPs effectively suppress the vascular endothelial growth factor (VEGF) expression of human umbilical vein endothelial cells (HUVECs). These results open the possibility to use this promising nanoformulation as an α-TOS delivery system for the effective cancer treatment, effectively resolving the current limitations of free α-TOS administration.

Developments in PDT Sensitizers for Increased Selectivity and Singlet Oxygen Production

Photodynamic therapy (PDT) is a minimally-invasive procedure that has been clinically approved for treating certain types of cancers. This procedure takes advantage of the cytotoxic activity of singlet oxygen (¹O₂) and other reactive oxygen species (ROS) produced by visible and NIR light irradiation of dye sensitizers following their accumulation in malignant cells. The main two concerns associated with certain clinically-used PDT sensitizers that have been influencing research in this arena are low selectivity toward malignant cells and low levels of ¹O₂ production in aqueous media. Solving the selectivity issue would compensate for photosensitizer concerns such as dark toxicity and aggregation in aqueous media. One main approach to enhancing dye selectivity involves taking advantage of key methods used in pharmaceutical drug delivery. This approach lies at the heart of the recent developments in PDT research and is a point of emphasis in the present review. Of particular interest has been the development of polymeric micelles as nanoparticles for delivering hydrophobic (lipophilic) and amphiphilic photosensitizers to the target cells. This review also covers methods employed to increase ¹O₂ production efficiency, including the design of two-photon absorbing sensitizers and triplet forming cyclometalated Ir(III) complexes.

Peptide GE11-Polyethylene Glycol-Polyethylenimine for targeted gene delivery in laryngeal cancer

The objective of this study was to evaluate the possibility of using GE11-polyethylene glycol-polyethylenimine (GE11-PEG-PEI) for targeted gene delivery to treat epidermal growth factor receptor (EGFR)-overexpressing laryngeal cancer. This study described the design, characterization, and in vitro and in vivo study of the nanocarrier GE11-PEG-PEI for gene delivery to treat laryngeal cancer. Analysis of the sizes and zeta potentials indicated that the formation of PEGylated complexes was dependent on the N/P ratio, and these complexes were capable of binding plasmid DNA and condensing DNA into small positively charged nanoparticles. The results also revealed that GE11-PEG-PEI had a weaker effect on cell survival in vitro. Gene transfection was performed on human laryngeal cancer Hep-2 cells in vitro and in vivo. Both the in vitro and in vivo results demonstrated that GE11-PEG-PEI had greater transfection efficiency than mPEG-PEI. Compared with mPEG-PEI/pORF-hTRAIL and saline, GE11-PEG-PEI/pORFh-TRAIL significantly (p < 0.05) reduced tumor growth in nude mice with laryngeal cancer. Moreover, the GE11-PEG-PEI/pORF-hTRAIL-treated groups showed more apoptosis than the mPEG-PEI/pORF-hTRAIL-treated groups. Therefore, our results showed that the peptide GE11 conjugated to PEG-PEI delivered significantly more genes to EGFR-overexpressing laryngeal cancer cells in vivo, indicating that GE11-PEG-PEI may be a suitable gene vector for treating EGFR-overexpressing laryngeal cancer.

Targeted photodynamic therapy in head and neck squamous cell carcinoma: heading into the future

The aim of this article is to give an insight into the future of photodynamic therapy (PDT) in head and neck squamous cell carcinoma (HNSCC). Through the combination of a photosensitizing agent with light and oxygen, PDT produces highly cytotoxic reactive oxygen species leading to selective tumor eradication. PDT is an attractive treatment for focal therapy of localized tumors, especially in the case of unresectable tumors. In HNSCC, over 1500 patients have been treated by PDT, and the majority of them responded quite favorably to this treatment. However, the non-negligible photosensitization of healthy tissue is a major limitation for the clinical application of PDT. Improvement in tumor selectivity is the main challenge that can be taken up by the use of a new generation of photosensitizing nanoparticles. Passive targeting, by using functionalised nanocarriers to target to overexpressed transmembrane receptors afford attractive solutions. To this day, epidermal growth factor receptor (EGFR) remains the only validated molecular target for HNSCC, and photosensitizer immunoconjugates to EGFR have been developed for the intracellular delivery of photosensitizing agents. Depending on coordinated research between biomarkers, specific ligands, and photosensitizers, similar approaches could be rapidly developed. In addition, some photosensitizers hold high fluorescence yield and therefore could emerge as theranostic agents.

Nanoparticle-based targeted therapeutics in head-and-neck cancer

Head-and-neck cancer is a major form of the disease worldwide. Treatment consists of surgery, radiation therapy and chemotherapy, but these have not resulted in improved survival rates over the past few decades. Versatile nanoparticles, with selective tumor targeting, are considered to have the potential to improve these poor outcomes. Application of nanoparticle-based targeted therapeutics has extended into many areas, including gene silencing, chemotherapeutic drug delivery, radiosensitization, photothermal therapy, and has shown much promise. In this review, we discuss recent advances in the field of nanoparticle-mediated targeted therapeutics for head-and-neck cancer, with an emphasis on the description of targeting points, including future perspectives.

Triple-responsive expansile nanogel for tumor and mitochondria targeted photosensitizer delivery

A pH, thermal, and redox potential triple-responsive expansile nanogel system (TRN), which swells at acidic pH, temperature higher than its transition temperature, and reducing environment, has been developed. TRN quickly expands from 108 nm to over 1200 nm (in diameter), achieving more than 1000-fold size enlargement (in volume), within 2 h in a reducing environment at body temperature. Sigma-2 receptor targeting-ligand functionalized TRN can effectively target head and neck tumor, and help Pc 4 targeting mitochondria inside cancer cells to achieve enhanced photodynamic therapy efficacy.

Targeted iron-oxide nanoparticle for photodynamic therapy and imaging of head and neck cancer

Photodynamic therapy (PDT) is a highly specific anticancer treatment modality for various cancers, particularly for recurrent cancers that no longer respond to conventional anticancer therapies. PDT has been under development for decades, but light-associated toxicity limits its clinical applications. To reduce the toxicity of PDT, we recently developed a targeted nanoparticle (NP) platform that combines a second-generation PDT drug, Pc 4, with a cancer targeting ligand, and iron oxide (IO) NPs. Carboxyl functionalized IO NPs were first conjugated with a fibronectin-mimetic peptide (Fmp), which binds integrin β1. Then the PDT drug Pc 4 was successfully encapsulated into the ligand-conjugated IO NPs to generate Fmp-IO-Pc 4. Our study indicated that both nontargeted IO-Pc 4 and targeted Fmp-IO-Pc 4 NPs accumulated in xenograft tumors with higher concentrations than nonformulated Pc 4. As expected, both IO-Pc 4 and Fmp-IO-Pc 4 reduced the size of HNSCC xenograft tumors more effectively than free Pc 4. Using a 10-fold lower dose of Pc 4 than that reported in the literature, the targeted Fmp-IO-Pc 4 NPs demonstrated significantly greater inhibition of tumor growth than nontargeted IO-Pc 4 NPs. These results suggest that the delivery of a PDT agent Pc 4 by IO NPs can enhance treatment efficacy and reduce PDT drug dose. The targeted IO-Pc 4 NPs have great potential to serve as both a magnetic resonance imaging (MRI) agent and PDT drug in the clinic.

High transfection efficiency of quantum dot-antisense oligonucleotide nanoparticles in cancer cells through dual-receptor synergistic targeting

Incorporating ligands with nanoparticle-based carriers for specific delivery of therapeutic nucleic acids (such as antisense oligonucleotides and siRNA) to tumor sites is a promising approach in anti-cancer strategies. However, nanoparticle-based carriers remain insufficient in terms of the selectivity and transfection efficiency. In this paper, we designed a dual receptor-targeted QDs gene carrier QD-(AS-ODN+GE11+c(RGDfK)) which could increase the cellular uptake efficiency and further enhance the transfection efficiency. Here, the targeting ligands used were peptides GE11 and c(RGDfK) which could recognize epidermal growth factor receptors (EGFR) and integrin ανβ3 receptors, respectively. Quantitative flow cytometry and ICP/MS showed that the synergistic effect between EGFR and integrin ανβ3 increased the cellular uptake of QDs carriers. The effects of inhibition agents showed the endocytosis pathway of QD-(AS-ODN+GE11+c(RGDfK)) probe was mainly clathrin-mediated. Western blot confirmed that QD-(AS-ODN+GE11+c(RGDfK)) could further enhance gene silencing efficiency compared to QD-(AS-ODN+GE11) and QD-(AS-ODN+c(RGDfK)), suggesting this dual receptor-targeted gene carrier achieved desired transfection efficiency. In this gene delivery system, QDs could not only be used as a gene vehicle but also as fluorescence probe, allowing for localization and tracking during the delivery process. This transport model is very well referenced for non-viral gene carriers to enhance the targeting ability and transfection efficiency.

Cannabinoid CB2 receptor as a new phototherapy target for the inhibition of tumor growth

The success of targeted cancer therapy largely relies upon the selection of target and the development of efficient therapeutic agents that specifically bind to the target. In the current study, we chose a cannabinoid CB2 receptor (CB2R) as a new target and used a CB2R-targeted photosensitizer, IR700DX-mbc94, for phototherapy treatment. IR700DX-mbc94 was prepared by conjugating a photosensitizer, IR700DX, to mbc94, whose binding specificity to CB2R has been previously demonstrated. We found that phototherapy treatment using IR700DX-mbc94 greatly inhibited the growth of CB2R positive tumors but not CB2R negative tumors. In addition, phototherapy treatment with nontargeted IR700DX did not show significant therapeutic effect. Similarly, treatment with IR700DX-mbc94 without light irradiation or light irradiation without the photosensitizer showed no tumor-inhibitory effect. Taken together, IR700DX-mbc94 is a promising phototherapy agent with high target-specificity. Moreover, CB2R appears to have great potential as a phototherapeutic target for cancer treatment.

EGFR-targeted poly(ethylene glycol)-distearoylphosphatidylethanolamine micelle loaded with paclitaxel for laryngeal cancer: preparation, characterization and in vitro evaluation

The objective of this study was to evaluate the potential of using polymeric micelles modified with a peptide (termed GE11) ligand of epidermal growth factor receptor as the targeted carriers to achieve increased accumulation in laryngeal cancer and enhanced intracellular delivery for the encapsulated anticancer drugs. Poly (ethylene glycol)-distearoylphosphatidylethanolamine (PEG-DSPE) micelles containing paclitaxel were prepared via film-hydration method followed by investigation of in vitro release of paclitaxel in phosphate-buffered saline. The average size of GE11-PEG-DSPE/paclitaxel micelle and mPEG-DSPE/paclitaxel were 35 ± 2.8 nm [the polydispersity index (PDI) = 0.207] and 28 ± 2.1 nm (PDI = 0.154), respectively. Micelles with or without GE11-modified had similar physicochemical properties. Transmission electron microscopy showed that the micelles were homogeneous and spherical in shape. Encapsulation efficiency and drug loading of the micelle were 74.11 ± 3.89% and 3.58 ± 2.82%, respectively. The in vitro targeting characteristic of GE11-modified micelles was investigated by observing the level of cellular uptake of fluorescent coumarin-6-loaded micelles on EGFR over-expressed human laryngeal cancer cell line Hep-2 and EGFR low-expressed human leukemic cell line U-937. Hep-2 cell proliferation was significantly inhibited by GE11-PEG-DSPE/paclitaxel micelle compared to mPEG-DSPE/paclitaxel micelle and Taxol in vitro. Our results suggested that GE11-PEG-DSPE micelle could be a promising strategy for enhancing paclitaxel's chemotherapeutic effects on EGFR over-expressed cancer cells.

Block copolymer nanoassemblies for photodynamic therapy and diagnosis

Light can be a powerful therapeutic and diagnostic tool. Light-sensitive molecules can be used to develop locally targeted cancer therapeutics. This approach is known as photodynamic therapy (PDT). Similarly, it is possible to diagnose diseases and track the course of treatment in vivo using ligh-sensitive molecules. This methodology is referred to as photodynamic diagnosis (PDD). Despite the potential, many PDT and PDD agents have imperfect physiochemical properties for their successful clinical application. Nanotechnology may solve these issues by improving the viability of PDT and PDD. This review summarizes the current state of PDT and PDD development, the integration of nanotechnology in the field, and the prospective future applications, demonstrating the potential of PDT and PDD for improved cancer treatment and diagnosis.

Hematoporphyrin monomethyl ether-mediated photodynamic therapy selectively kills sarcomas by inducing apoptosis

We investigated the antitumor effect and mechanism of hematoporphyrin monomethyl ether-mediated photodynamic therapy (HMME-PDT) in sarcomas. Intracellular uptake of HMME by osteosarcoma cells (LM8 and K7) was time- and dose-dependent, while this was not observed for myoblast cells (C2C12) and fibroblast cells (NIH/3T3). HMME-PDT markedly inhibited the proliferation of sarcoma cell lines (LM8, MG63, Saos-2, SW1353, TC71, and RD) (P<0.05), and the killing effect was improved with increased HMME concentration and energy intensity. Flow cytometry analysis revealed that LM8, MG63, and Saos-2 cells underwent apoptosis after treatment with HMME-PDT. Additionally, apoptosis was induced after HMME-PDT in a three-dimensional culture of osteosarcoma cells. Hoechst 33342 staining confirmed apoptosis. Cell death caused by PDT was rescued by an irreversible inhibitor (Z-VAD-FMK) of caspase. However, cell viability was not markedly decreased compared with the HMME-PDT group. Expression levels of caspase-1, caspase-3, caspase-6, caspase-9, and poly (ADP-ribose) polymerase (PARP) proteins were markedly up-regulated in the treatment groups and increased with HMME concentration as determined by western blot analysis. In vivo, tumor volume markedly decreased at 7–16 days post-PDT. Hematoxylin and eosin staining revealed widespread necrotic and infiltrative inflammatory cells in the HMME-PDT group. Immunohistochemistry analysis also showed that caspase-1, caspase-3, caspase-6, caspase-9, and PARP proteins were significantly increased in the HMME-PDT group. These results indicate that HMME-PDT has a potent killing effect on osteosarcoma cells in vitro and significantly inhibits tumor growth in vivo, which is associated with the caspase-dependent pathway.