Photodynamic Therapy and the Biophysics of the Tumor Microenvironment

Overcoming the effects of fluid shear stress in ovarian cancer cell lines: Doxorubicin alone or photodynamic priming to target platinum resistance

Resistance to platinum-based chemotherapies remains a significant challenge in advanced-stage high-grade serous ovarian carcinoma, and patients with malignant ascites face the poorest outcomes. It is, therefore, important to understand the effects of ascites, including the associated fluid shear stress (FSS), on phenotypic changes and therapy response, specifically FSS-induced chemotherapy resistance and the underlying mechanisms in ovarian cancer. This study investigated the effects of FSS on response to cisplatin, a platinum-based chemotherapy, and doxorubicin, an anthracycline, both of which are commonly used to manage advanced-stage ovarian cancer. Consistent with prior research, OVCAR-3 and Caov-3 cells cultivated under FSS demonstrated significant resistance to cisplatin. Examination of the role of mitochondria revealed an increase in mitochondrial DNA copy number and intracellular ATP content in cultures grown under FSS, suggesting that changes in mitochondria number and metabolic activity may contribute to platinum resistance. Interestingly, no resistance to doxorubicin was observed under FSS, the first such observation of a lack of resistance under these conditions. Finally, this study demonstrated the potential of photodynamic priming using benzoporphyrin derivative, a clinically approved photosensitizer that localizes in part to mitochondria and endoplasmic reticula, to enhance the efficacy of cisplatin, but not doxorubicin, thereby overcoming FSS-induced platinum resistance.

Assays on 3D tumor spheroids for exploring the light dosimetry of photodynamic effects under different gaseous conditions

The multifaceted nature of photodynamic therapy (PDT) requires a throughout evaluation of a multitude of parameters when devising preclinical protocols. In this study, we constructed MCF-7 human breast tumor spheroid assays to infer PDT irradiation doses at four gradient levels for violet light at 408 nm and red light at 625 nm under normal and hypoxic oxygen conditions. The compacted three-dimensional (3D) tumor models conferred PDT resistance as compared to monolayer cultures due to heterogenous distribution of photosensitizers along with the presence of internal hypoxic region. Cell viability results indicated that the violet light was more efficient to kill cells in the spheroids under normal oxygen conditions, while cells exposed to the hypoxic microenvironment exhibited minimal PDT-induced death. The combination of 3D tumor spheroid assays and the multiparametric screening platform presented a solid framework for assessing PDT efficacy across a wide range of different physiological conditions and therapeutic regimes.

Modulation of heat shock protein expression and cytokine levels in MCF-7 cells through photodynamic therapy

In this study, we assess the impact of photodynamic therapy (PDT) using aluminum phthalocyanine tetrasulfonate (AlPcS4) on the viability and cellular stress responses of MCF-7 breast cancer cells. Specifically, we investigate changes in cell viability, cytokine production, and the expression of stress-related genes. Experimental groups included control cells, those treated with AlPcS4 only, light-emitting diode (LED) only, and combined PDT. To evaluate these effects on cell viability, cytokine production, and the expression of stress-related genes, techniques such as 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, enzyme-linked immunosorbent assays (ELISA), and real-time quantitative PCR (RT‒qPCR) were employed. Our findings reveal how PDT with AlPcS4 modulates mitochondrial activity and cytokine responses, shedding light on the cellular pathways essential for cell survival and stress adaptation. This work enhances our understanding of PDT's therapeutic potential and mechanisms in treating breast cancer.

Enhancing cancer immunotherapy with photodynamic therapy and nanoparticle: making tumor microenvironment hotter to make immunotherapeutic work better

Cancer immunotherapy has made tremendous advancements in treating various malignancies. The biggest hurdle to successful immunotherapy would be the immunosuppressive tumor microenvironment (TME) and low immunogenicity of cancer cells. To make immunotherapy successful, the 'cold' TME must be converted to 'hot' immunostimulatory status to activate residual host immune responses. To this end, the immunosuppressive equilibrium in TME should be broken, and immunogenic cancer cell death ought to be induced to stimulate tumor-killing immune cells appropriately. Photodynamic therapy (PDT) is an efficient way of inducing immunogenic cell death (ICD) of cancer cells and disrupting immune-restrictive tumor tissues. PDT would trigger a chain reaction that would make the TME 'hot' and have ICD-induced tumor antigens presented to immune cells. In principle, the strategic combination of PDT and immunotherapy would synergize to enhance therapeutic outcomes in many intractable tumors. Novel technologies employing nanocarriers were developed to deliver photosensitizers and immunotherapeutic to TME efficiently. New-generation nanomedicines have been developed for PDT immunotherapy in recent years, which will accelerate clinical applications.

Shedding Light on Chemoresistance: The Perspective of Photodynamic Therapy in Cancer Management

The persistent failure of standard chemotherapy underscores the urgent need for innovative and targeted approaches in cancer treatment. Photodynamic therapy (PDT) has emerged as a promising photochemistry-based approach to address chemoresistance in cancer regimens. PDT not only induces cell death but also primes surviving cells, enhancing their susceptibility to subsequent therapies. This review explores the principles of PDT and discusses the concept of photodynamic priming (PDP), which augments the effectiveness of treatments like chemotherapy. Furthermore, the integration of nanotechnology for precise drug delivery at the right time and location and PDT optimization are examined. Ultimately, this study highlights the potential and limitations of PDT and PDP in cancer treatment paradigms, offering insights into future clinical applications.

Co-Packaged PARP inhibitor and photosensitizer for targeted photo-chemotherapy of 3D ovarian cancer spheroids

BACKGROUND

Within the last decade, poly(ADP-ribose) polymerase inhibitors (PARPi) have emerged in the clinic as an effective treatment for numerous malignancies. Preclinical data have demonstrated powerful combination effects of PARPi paired with photodynamic therapy (PDT), which involves light-activation of specialized dyes (photosensitizers) to stimulate cancer cell death through reactive oxygen species generation.

RESULTS

In this report, the most potent clinical PARP inhibitor, talazoparib, is loaded into the core of a polymeric nanoparticle (NP-Tal), which is interfaced with antibody-photosensitizer conjugates (photoimmunoconjugates, PICs) to form PIC-NP-Tal. In parallel, a new 3D fluorescent coculture model is developed using the parental OVCAR-8-DsRed2 and the chemo-resistant subline, NCI/ADR-RES-EGFP. This model enables quantification of trends in the evolutionary dynamics of acquired chemoresistance in response to various treatment regimes. Results reveal that at a low dosage (0.01 μM), NP-Tal kills the parental cells while sparing the chemo-resistant subline, thereby driving chemoresistance. Next, PIC-NP-Tal and relevant controls are evaluated in the 3D coculture model at multiple irradiation doses to characterize effects on total spheroid ablation and relative changes in parental and subline cell population dynamics. Total spheroid ablation data shows potent combination effects when PIC and NP-Tal are co-administered, but decreased efficacy with the conjugated formulation (PIC-NP-Tal). Analysis of cell population dynamics reveals that PIC, BPD + NP-Tal, PIC + NP-Tal, and PIC-NP-Tal demonstrate selection pressures towards chemoresistance.

CONCLUSIONS

This study provides key insights into manufacturing parameters for PARPi-loaded nanoparticles, as well as the potential role of PDT-based combination therapies in the context of acquired drug resistance.

Nano-phototherapy: Favorable prospects for cancer treatment

Nanotechnology-based phototherapies have drawn interest in the fight against cancer because of its noninvasiveness, high flexibility, and precision in terms of cancer targeting and drug delivery based on its surface properties and size. Phototherapy has made remarkable development in recent decades. Approaches to phototherapy, which utilize nanomaterials or nanotechnology have emerged to contribute to advances around nanotechnologies in medicine, particularly for cancers. A brief overviews of the development of photodynamic therapy as well as its mechanism in cancer treatment is provided. We emphasize the design of novel nanoparticles utilized in photodynamic therapy while summarizing the representative progress during the recent years. Finally, to forecast important future research in this area, we examine the viability and promise of photodynamic therapy systems based on nanoparticles in clinical anticancer treatment applications and briefly make mention of the elimination of all reactive metabolites pertaining to nano formulations inside living organisms providing insight into clinical mechanistic processes. Future developments and therapeutic prospects for photodynamic treatments are anticipated. Our viewpoints might encourage scientists to create more potent phototherapy-based cancer therapeutic modalities. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Exploiting Unique Features of Microneedles to Modulate Immunity

Microneedle arrays (MNAs) are small patches containing hundreds of short projections that deliver signals directly to dermal layers without causing pain. These technologies are of special interest for immunotherapy and vaccine delivery because they directly target immune cells concentrated in the skin. The targeting abilities of MNAs result in efficient immune responses-often more protective or therapeutic-compared to conventional needle delivery. MNAs also offer logistical benefits, such as self-administration and transportation without refrigeration. Thus, numerous preclinical and clinical studies are exploring these technologies. Here the unique advantages of MNA, as well as critical challenges-such as manufacturing and sterility issues-the field faces to enable widespread deployment are discussed. How MNA design parameters can be exploited for controlled release of vaccines and immunotherapies, and the application to preclinical models of infection, cancer, autoimmunity, and allergies are explained. Specific strategies are also discussed to reduce off-target effects compared to conventional vaccine delivery routes, and novel chemical and manufacturing controls that enable cargo stability in MNAs across flexible intervals and temperatures. Clinical research using MNAs is then examined. Drawbacks of MNAs and the implications, and emerging opportunities to exploit MNAs for immune engineering and clinical use are concluded.

Bibliometric Analysis to Global Research Status Quo on Photobiomodulation

Background: Photobiomodulation (PBM) becomes a remedial technology with growing popularity. The primary goal of this article is to conduct a PBM literature review, providing an overall systematic understanding of current and future trends. Methods: A dataset was made with topic retrieval, concerning PBM research retrieved from the Web of Science Core Collection. We analyzed to forecast research frontiers in this field using the softwares: VOSviewer, CiteSpace, and Biblioshiny. Results: Four thousand five hundred thirty pieces of literature were retrieved from our database. Current trends were characterized by keywords of "light," "spinal cord injury," "skeletal muscle," and so on. Future trends were characterized probably by six cutting-edge terms: "wound healing," "pain," "oral mucositis," "Alzheimer's disease," "Parkinson's disease," and "orthodontics." Conclusions: This study finds that the inadequacy of in-depth reliable interpretation of current clinical data calls for molecular biological mechanisms together with well-designed, large-sample, multicenter clinical trials. The study of oral, wound, and neural-related mechanisms and the exploration of therapeutic effects may be the popular trend at present and in the next few years.

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.

Transient fluid flow improves photoimmunoconjugate delivery and photoimmunotherapy efficacy

Circulating drugs in the peritoneal cavity is an effective strategy for advanced ovarian cancer treatment. Photoimmunotherapy, an emerging modality with potential for the treatment of ovarian cancer, involves near-infrared light activation of antibody-photosensitizer conjugates (photoimmunoconjugates) to generate cytotoxic reactive oxygen species. Here, a microfluidic cell culture model is used to study how fluid flow-induced shear stress affects photoimmunoconjugate delivery to ovarian cancer cells. Photoimmunoconjugates are composed of the antibody, cetuximab, conjugated to the photosensitizer, and benzoporphyrin derivative. Longitudinal tracking of photoimmunoconjugate treatment under flow conditions reveals enhancements in subcellular photosensitizer accumulation. Compared to static conditions, fluid flow-induced shear stress at 0.5 and 1 dyn/cm2 doubled the cellular delivery of photoimmunoconjugates. Fluid flow-mediated treatment with three different photosensitizer formulations (benzoporphyrin derivative, photoimmunoconjugates, and photoimmunoconjugate-coated liposomes) led to enhanced phototoxicity compared to static conditions. This study confirms the fundamental role of fluid flow-induced shear stress in the anti-cancer effects of photoimmunotherapy.

Combination of Two Photosensitisers in Anticancer, Antimicrobial and Upconversion Photodynamic Therapy

Photodynamic therapy (PDT) is a special form of phototherapy in which oxygen is needed, in addition to light and a drug called a photosensitiser (PS), to create cytotoxic species that can destroy cancer cells and various pathogens. PDT is often used in combination with other antitumor and antimicrobial therapies to sensitise cells to other agents, minimise the risk of resistance and improve overall outcomes. Furthermore, the aim of combining two photosensitising agents in PDT is to overcome the shortcomings of the monotherapeutic approach and the limitations of individual agents, as well as to achieve synergistic or additive effects, which allows the administration of PSs in lower concentrations, consequently reducing dark toxicity and preventing skin photosensitivity. The most common strategies in anticancer PDT use two PSs to combine the targeting of different organelles and cell-death mechanisms and, in addition to cancer cells, simultaneously target tumour vasculature and induce immune responses. The use of PDT with upconversion nanoparticles is a promising approach to the treatment of deep tissues and the goal of using two PSs is to improve drug loading and singlet oxygen production. In antimicrobial PDT, two PSs are often combined to generate various reactive oxygen species through both Type I and Type II processes.

Exploring Monocytes-Macrophages in Immune Microenvironment of Glioblastoma for the Design of Novel Therapeutic Strategies

Gliomas are primary malignant brain tumors. These tumors seem to be more and more frequent, not only because of a true increase in their incidence, but also due to the increase in life expectancy of the general population. Among gliomas, malignant gliomas and more specifically glioblastomas (GBM) are a challenge in their diagnosis and treatment. There are few effective therapies for these tumors, and patients with GBM fare poorly, even after aggressive surgery, chemotherapy, and radiation. Over the last decade, it is now appreciated that these tumors are composed of numerous distinct tumoral and non-tumoral cell populations, which could each influence the overall tumor biology and response to therapies. Monocytes have been proved to actively participate in tumor growth, giving rise to the support of tumor-associated macrophages (TAMs). In GBM, TAMs represent up to one half of the tumor mass cells, including both infiltrating macrophages and resident brain microglia. Infiltrating macrophages/monocytes constituted ~ 85% of the total TAM population, they have immune functions, and they can release a wide array of growth factors and cytokines in response to those factors produced by tumor and non-tumor cells from the tumor microenvironment (TME). A brief review of the literature shows that this cell population has been increasingly studied in GBM TME to understand its role in tumor progression and therapeutic resistance. Through the knowledge of its biology and protumoral function, the development of therapeutic strategies that employ their recruitment as well as the modulation of their immunological phenotype, and even the eradication of the cell population, can be harnessed for therapeutic benefit. This revision aims to summarize GBM TME and localization in tumor niches with special focus on TAM population, its origin and functions in tumor progression and resistance to conventional and experimental GBM treatments. Moreover, recent advances on the development of TAM cell targeting and new cellular therapeutic strategies based on monocyte/macrophages recruitment to eradicate GBM are discussed as complementary therapeutics.

Organic disulfide-modified folate carbon dots for tumor-targeted synergistic chemodynamic/photodynamic therapy

Carbon dots (CDs) have great potential for cancer diagnosis and treatment. Photodynamic therapy and chemodynamic therapy are promising treatments mediated by reactive oxygen species (ROS), which have the advantages of being minimally invasive, having no multi-drug resistance, and having no systemic toxic side effects. However, the tumor microenvironment (TME) and poor targetability often reduce the therapeutic effect. In this work, we have successfully prepared folate-based carbon dots (FCP-CDs) from folic acid (FA), citric acid (CA), and polyethyleneimine (PEI) for tumor-targeting. The surface of FCP-CDs was modified using organic disulfide, 3,3'-dithiodipropionic acid (DTPA), and a photosensitizer (PS) pyropheophorbide-a (PPa) to form a tumor microenvironment-responsive nanoplatform, FCP-CDs@DTPA@PPa (named FCPPD), for synergistic cancer therapy. The results showed that FCPPD effectively preserved the tumor target specificity of folic acid and the photodynamic therapeutic (PDT) activity of PPa, and could provide additional chemodynamic therapeutic (CDT) function by reacting with hydrogen peroxide (H₂O₂) to generate ˙OH. The introduction of DTPA, which contains disulfide bonds, endows FCPPD with an excellent ability to deplete glutathione (GSH) in tumors via intracellular redox reactions, amplifying intracellular oxidative strain and enhancing ROS-based therapeutic effects. Systematic in vitro and in vivo studies under various conditions have shown that the obtained FCPPD nanoparticles have good biocompatibility and could be a promising therapeutic agent for imaging-guided PDT/CDT combination therapy.

Photochemical Targeting of Mitochondria to Overcome Chemoresistance in Ovarian Cancer †

Ovarian cancer is the most lethal gynecologic malignancy with a stubborn mortality rate of ~65%. The persistent failure of multiline chemotherapy, and significant tumor heterogeneity, has made it challenging to improve outcomes. A target of increasing interest is the mitochondrion because of its essential role in critical cellular functions, and the significance of metabolic adaptation in chemoresistance. This review describes mitochondrial processes, including metabolic reprogramming, mitochondrial transfer and mitochondrial dynamics in ovarian cancer progression and chemoresistance. The effect of malignant ascites, or excess peritoneal fluid, on mitochondrial function is discussed. The role of photodynamic therapy (PDT) in overcoming mitochondria-mediated resistance is presented. PDT, a photochemistry-based modality, involves the light-based activation of a photosensitizer leading to the production of short-lived reactive molecular species and spatiotemporally confined photodamage to nearby organelles and biological targets. The consequential effects range from subcytotoxic priming of target cells for increased sensitivity to subsequent treatments, such as chemotherapy, to direct cell killing. This review discusses how PDT-based approaches can address key limitations of current treatments. Specifically, an overview of the mechanisms by which PDT alters mitochondrial function, and a summary of preclinical advancements and clinical PDT experience in ovarian cancer are provided.

Increasing cancer permeability by photodynamic priming: from microenvironment to mechanotransduction signaling

The dense cancer microenvironment is a significant barrier that limits the penetration of anticancer agents, thereby restraining the efficacy of molecular and nanoscale cancer therapeutics. Developing new strategies to enhance the permeability of cancer tissues is of major interest to overcome treatment resistance. Nonetheless, early strategies based on small molecule inhibitors or matrix-degrading enzymes have led to disappointing clinical outcomes by causing increased chemotherapy toxicity and promoting disease progression. In recent years, photodynamic therapy (PDT) has emerged as a novel approach to increase the permeability of cancer tissues. By producing excessive amounts of reactive oxygen species selectively in the cancer microenvironment, PDT increases the accumulation, penetration depth, and efficacy of chemotherapeutics. Importantly, the increased cancer permeability has not been associated to increased metastasis formation. In this review, we provide novel insights into the mechanisms by which this effect, called photodynamic priming, can increase cancer permeability without promoting cell migration and dissemination. This review demonstrates that PDT oxidizes and degrades extracellular matrix proteins, reduces the capacity of cancer cells to adhere to the altered matrix, and interferes with mechanotransduction pathways that promote cancer cell migration and differentiation. Significant knowledge gaps are identified regarding the involvement of critical signaling pathways, and to which extent these events are influenced by the complicated PDT dosimetry. Addressing these knowledge gaps will be vital to further develop PDT as an adjuvant approach to improve cancer permeability, demonstrate the safety and efficacy of this priming approach, and render more cancer patients eligible to receive life-extending treatments.

Tumor microenvironment in non-melanoma skin cancer resistance to photodynamic therapy

Non-melanoma skin cancer has recently seen an increase in prevalence, and it is estimated that this grow will continue in the coming years. In this sense, the importance of therapy effectiveness has increased, especially photodynamic therapy. Photodynamic therapy has attracted much attention as a minimally invasive, selective and repeatable approach for skin cancer treatment and prevention. Although its high efficiency, this strategy has also faced problems related to tumor resistance, where the tumor microenvironment has gained a well-deserved role in recent years. Tumor microenvironment denotes a wide variety of elements, such as cancer-associated fibroblasts, immune cells, endothelial cells or the extracellular matrix, where their interaction and the secretion of a wide diversity of cytokines. Therefore, the need of designing new strategies targeting elements of the tumor microenvironment to overcome the observed resistance has become evident. To this end, in this review we focus on the role of cancer-associated fibroblasts and tumor-associated macrophages in the resistance to photodynamic therapy. We are also exploring new approaches consisting in the combination of new and old drugs targeting these cells with photodynamic therapy to enhance treatment outcomes of non-melanoma skin cancer.

Modulating cancer-stroma crosstalk by a nanoparticle-based photodynamic method to pave the way for subsequent therapies

Cancer cells and their stromal microenvironment are mutually supportive. Either destroying cancer cells or damaging stromal components cannot guarantee a satisfactory outcome in the long-term treatment. Herein, we showed that the tumor-stroma crosstalk was disturbed by nanoparticle-based photodynamic therapy (PDT) in pancreatic tumor models, leading to the persistent inhibition of extracellular matrix (ECM) secretion and the enhanced therapeutic effect. By employing a conditioned medium method, we found that the nanoparticulate PDT at a sub-lethal dosage down-regulated TGFβ signaling pathways, leading to the decrease in drug resistance, proliferation, and migration of the cancer cells. Meanwhile, pancreatic stellate cells (PSCs) were inactivated by PDT, hindering the secretion of ECM. Combining the results that PDT indiscriminately killed PSCs and cancer cells, we showed that the mutual support between the cancer cells and the stroma was interrupted. We further presented the inhibition of the crosstalk persistently enhanced tumor penetration in stroma-rich pancreatic tumor models. The loosened stroma not only facilitated tumor eradication by subsequent therapy but also improved the efficiency of gemcitabine treatment on monthly later recurrent tumors. Therefore, our work may boost the potential of PDT to be a valuable individual or adjuvant treatment for desmoplastic cancers.

MMP-2 Inhibitor-Mediated Tumor Microenvironment Regulation Using a Sequentially Released Bio-Nanosystem for Enhanced Cancer Photo-Immunotherapy

Combining photodynamic therapy (PDT) with natural killer (NK) cell-based immunotherapy has shown great potential against cancers, but the shedding of NK group 2, member D ligands (NKG2DLs) on tumor cells inhibited NK cell activation in the tumor microenvironment. Herein, we assembled microenvironment-/light-responsive bio-nanosystems (MLRNs) consisting of SB-3CT-containing β-cyclodextrins (β-CDs) and photosensitizer-loaded liposomes, in which SB-3CT was considered to remodel the tumor microenvironment. β-CDs and liposomes were linked by metalloproteinase 2 (MMP-2) responsive peptides, enabling sequential release of SB-3CT and chlorin e6 triggered by the MMP-2-abundant tumor microenvironment and 660 nm laser irradiation, respectively. Released SB-3CT blocked tumor immune escape by antagonizing MMP-2 and promoting the NKG2D/NKG2DL pathway, while liposomes were taken up by tumor cells for PDT. MLRN-mediated photo-immunotherapy significantly induced melanoma cell cytotoxicity (83.31%), inhibited tumor growth (relative tumor proliferation rate: 1.13% of that of normal saline) in the xenografted tumor model, and enhanced tumor-infiltrating NK cell (148 times) and NKG2DL expression (9.55 and 16.52 times for MICA and ULBP-1, respectively), achieving a synergistic effect. This study not only provided a simple insight into the development of new nanomedicine for programed release of antitumor drugs and better integration of PDT and immunotherapy but also a novel modality for clinical NK cell-mediated immunotherapy against melanoma.

Ultrasound-Responsive Nanocarriers for Breast Cancer Chemotherapy

Breast cancer is the most common type of cancer and it is treated with surgical intervention, radiotherapy, chemotherapy, or a combination of these regimens. Despite chemotherapy's ample use, it has limitations such as bioavailability, adverse side effects, high-dose requirements, low therapeutic indices, multiple drug resistance development, and non-specific targeting. Drug delivery vehicles or carriers, of which nanocarriers are prominent, have been introduced to overcome chemotherapy limitations. Nanocarriers have been preferentially used in breast cancer chemotherapy because of their role in protecting therapeutic agents from degradation, enabling efficient drug concentration in target cells or tissues, overcoming drug resistance, and their relatively small size. However, nanocarriers are affected by physiological barriers, bioavailability of transported drugs, and other factors. To resolve these issues, the use of external stimuli has been introduced, such as ultrasound, infrared light, thermal stimulation, microwaves, and X-rays. Recently, ultrasound-responsive nanocarriers have become popular because they are cost-effective, non-invasive, specific, tissue-penetrating, and deliver high drug concentrations to their target. In this paper, we review recent developments in ultrasound-guided nanocarriers for breast cancer chemotherapy, discuss the relevant challenges, and provide insights into future directions.

Critical PDT theory II: Current concepts and indications

While photodynamic therapy (PDT) is effective for the eradication of select neoplasia and certain other pathologic conditions, it has yet to achieve wide acceptance in clinical medicine. A variety of factors contribute to this situation including relations with the pharmaceutical industry that have often been problematic. Some current studies relating to photodynamic effects are 'phenomenological', i.e., they describe phenomena that only reiterate what is already known. The net result has been a tendency of granting agencies to become disillusioned with support for PDT research. This report is intended to provide some thoughts on current research efforts that improve clinical relevance and those that do not.

Metallated phthalocyanines and their hydrophilic derivatives for multi-targeted oncological photodynamic therapy

BACKGROUND AND AIM

A photosensitizer (PS) delivery and comprehensive tumor targeting platform was developed that is centered on the photosensitization of key pharmacological targets in solid tumors (cancer cells, tumor vascular endothelium, and cellular and non-cellular components of the tumor microenvironment) before photodynamic therapy (PDT). Interstitially targeted liposomes (ITLs) encapsulating zinc phthalocyanine (ZnPC) and aluminum phthalocyanine (AlPC) were formulated for passive targeting of the tumor microenvironment. In previous work it was established that the PEGylated ITLs were taken up by cultured cholangiocarcinoma cells. The aim of this study was to verify previous results in cancer cells and to determine whether the ITLs can also be used to photosensitize cells in the tumor microenvironment and vasculature. Following positive results, rudimentary in vitro and in vivo experiments were performed with ZnPC-ITLs and AlPC-ITLs as well as their water-soluble tetrasulfonated derivatives (ZnPCS4 and AlPCS4) to assemble a research dossier and bring this platform closer to clinical transition.

METHODS

Flow cytometry and confocal microscopy were employed to determine ITL uptake and PS distribution in cholangiocarcinoma (SK-ChA-1) cells, endothelial cells (HUVECs), fibroblasts (NIH-3T3), and macrophages (RAW 264.7). Uptake of ITLs by endothelial cells was verified under flow conditions in a flow chamber. Dark toxicity and PDT efficacy were determined by cell viability assays, while the mode of cell death and cell cycle arrest were assayed by flow cytometry. In vivo systemic toxicity was assessed in zebrafish and chicken embryos, whereas skin phototoxicity was determined in BALB/c nude mice. A PDT efficacy pilot was conducted in BALB/c nude mice bearing human triple-negative breast cancer (MDA-MB-231) xenografts.

RESULTS

The key findings were that (1) photodynamically active PSs (i.e., all except ZnPCS4) were able to effectively photosensitize cancer cells and non-cancerous cells; (2) following PDT, photodynamically active PSs were highly toxic-to-potent as per anti-cancer compound classification; (3) the photodynamically active PSs did not elicit notable systemic toxicity in zebrafish and chicken embryos; (4) ITL-delivered ZnPC and ZnPCS4 were associated with skin phototoxicity, while the aluminum-containing PSs did not exert detectable skin phototoxicity; and (5) ITL-delivered ZnPC and AlPC were equally effective in their tumor-killing capacity in human tumor breast cancer xenografts and superior to other non-phthalocyanine PSs when appraised on a per mole administered dose basis.

CONCLUSIONS

AlPC(S4) are the safest and most effective PSs to integrate into the comprehensive tumor targeting and PS delivery platform. Pending further in vivo validation, these third-generation PSs may be used for multi-compartmental tumor photosensitization.

Photoimmunotherapy Retains Its Anti-Tumor Efficacy with Increasing Stromal Content in Heterotypic Pancreatic Cancer Spheroids

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease characterized by increased levels of desmoplasia that contribute to reduced drug delivery and poor treatment outcomes. In PDAC, the stromal content can account for up to 90% of the total tumor volume. The complex interplay between stromal components, including pancreatic cancer-associated fibroblasts (PCAFs), and PDAC cells in the tumor microenvironment has a significant impact on the prognoses and thus needs to be recapitulated in vitro when evaluating various treatment strategies. This study is a systematic evaluation of photodynamic therapy (PDT) in 3D heterotypic coculture models of PDAC with varying ratios of patient-derived PCAFs that simulate heterogeneous PDAC tumors with increasing stromal content. The efficacy of antibody-targeted PDT (photoimmunotherapy; PIT) using cetuximab (a clinically approved anti-EGFR antibody) photoimmunoconjugates (PICs) of a benzoporphyrin derivative (BPD) is contrasted with that of liposomal BPD (Visudyne), which is currently in clinical trials for PDT of PDAC. We demonstrate that both Visudyne-PDT and PIT were effective in heterotypic PDAC 3D spheroids with a low stromal content. However, as the stromal content increases above 50% in the 3D spheroids, the efficacy of Visudyne-PDT is reduced by up to 10-fold, while PIT retains its efficacy. PIT was found to be 10-, 19-, and 14-fold more phototoxic in spheroids with 50, 75, and 90% PCAFs, respectively, as compared to Visudyne-PDT. This marked difference in efficacy is attributed to the ability of PICs to penetrate and distribute homogeneously within spheroids with a higher stromal content and the mechanistically different modes of action of the two formulations. This study thus demonstrates how the stromal content in PDAC spheroids directly impacts their responsiveness to PDT and proposes PIT to be a highly suited treatment option for desmoplastic tumors with particularly high degrees of stromal content.

Light-triggered photodynamic nanomedicines for overcoming localized therapeutic efficacy in cancer treatment

Photodynamic nanomedicines have significantly enhanced the therapeutic efficacy of photosensitizers (PSs) by overcoming critical limitations of PSs such as poor water solubility and low tumor accumulation. Furthermore, functional photodynamic nanomedicines have enabled overcoming oxygen depletion during photodynamic therapy (PDT) and tissue light penetration limitation by supplying oxygen or upconverting light in targeted tumor tissues, resulting in providing the potential to overcome biological therapeutic barriers of PDT. Nevertheless, their localized therapeutic effects still remain a huddle for the effective treatment of metastatic- or recurrent tumors. Recently, newly designed photodynamic nanomedicines and their combination chemo- or immune checkpoint inhibitor therapy enable the systemic treatment of various metastatic tumors by eliciting antitumor immune responses via immunogenic cell death (ICD). This review introduces recent advances in photodynamic nanomedicines and their applications, focusing on overcoming current limitations. Finally, the challenges and future perspectives of the clinical translation of photodynamic nanomedicines in cancer PDT are discussed.

Malignant Central Airway Obstruction: What's New?

Malignant central airway obstruction (MCAO) is a debilitating and life-limiting complication that occurs in an unfortunately large number of individuals with advanced intrathoracic cancer. Although the management of MCAO is multimodal and interdisciplinary, the task of providing patients with prompt palliation falls increasingly on the shoulders of interventional pulmonologists. While a variety of tools and techniques are available for the management of malignant obstructive lesions, advancements and evolution in this therapeutic venue have been somewhat sluggish and limited when compared with other branches of interventional pulmonary medicine (e.g., the early diagnosis of peripheral lung nodules). Indeed, one pragmatic, albeit somewhat uncharitable, reading of this article's title might suggest a wry smile and shug of the shoulders as to imply that relatively little has changed in recent years. That said, the spectrum of interventions for MCAO continues to expand, even if at a less impressive clip. Herein, we present on MCAO and its endoscopic and nonendoscopic management-that which is old, that which is new, and that which is still on the horizon.

Targeting Microenvironment of Melanoma and Head and Neck Cancers in Photodynamic Therapy

Background:

Photodynamic therapy (PDT), in comparison to other skin cancers, is still far less effective for melanoma, due to the strong absorbance and the role of melanin in cytoprotection. The tumour microenvironment (TME) has a significant role in tumour progression, and the hypoxic TME is one of the main reasons for melanoma progression to metastasis and its resistance to PDT. Hypoxia is also a feature of solid tumours in the head and neck region that indicates negative prognosis.

Objective:

The aim of this study was to individuate and describe systematically the main strategies in targeting the TME, especially hypoxia, in PDT against melanoma and head and neck cancers (HNC), and assess the current success in their application.

Methods:

PubMed was used for searching, in MEDLINE and other databases, for the most recent publications on PDT against melanoma and HNC in combination with the TME targeting and hypoxia.

Results:

In PDT for melanoma and HNC, it is very important to control hypoxia levels, and amongst the different approaches, oxygen self-supply systems are often applied. Vascular targeting is promising, but to improve it, optimal drug-light interval, and formulation to increase the accumulation of the photosensitiser in the tumour vasculature, have to be established. On the other side, the use of angiogenesis inhibitors, such as those interfering with VEGF signalling, is somewhat less successful than expected and needs to be further investigated.

Conclusion:

The combination of PDT with immunotherapy by using multifunctional nanoparticles continues to develop and seems to be the most promising for achieving a complete and lasting antitumour effect.

Dimensional Reduction Enhances Photodynamic Therapy of Metal-Organic Nanophotosensitizers

Herein we report that dimensional reduction from three-dimensional nanoscale metal-organic frameworks (nMOFs) to two-dimensional nanoscale metal-organic layers (nMOLs) increases the frequency of encounters between photosensitizers and oxygen and facilitates the diffusion of singlet oxygen from the nMOL to significantly enhance photodynamic therapy. The nMOFs and nMOLs share the same M₁₂-oxo (M = Zr, Hf) secondary building units and 5,15-di-p-benzoatoporphyrin (DBP) ligands but exhibit three-dimensional and two-dimensional topologies, respectively. Molecular dynamics simulations and experimental studies revealed that the nMOLs with a monolayer morphology enhanced the generation of reactive oxygen species and exhibited over an order of magnitude higher cytotoxicity over the nMOFs. In a mouse model of triple-negative breast cancer, Hf-DBP nMOL showed 49.1% more tumor inhibition, an 80% higher cure rate, and 16.3-fold lower metastasis potential than Hf-DBP nMOF.

Microtentacle Formation in Ovarian Carcinoma

BACKGROUND

The development of chemoresistance to paclitaxel and carboplatin represents a major therapeutic challenge in ovarian cancer, a disease frequently characterized by malignant ascites and extrapelvic metastasis. Microtentacles (McTNs) are tubulin-based projections observed in detached breast cancer cells. In this study, we investigated whether ovarian cancers exhibit McTNs and characterized McTN biology.

METHODS

We used an established lipid-tethering mechanism to suspend and image individual cancer cells. We queried a panel of immortalized serous (OSC) and clear cell (OCCC) cell lines as well as freshly procured ascites and human ovarian surface epithelium (HOSE). We assessed by Western blot β-tubulin isotype, α-tubulin post-translational modifications and actin regulatory proteins in attached/detached states. We studied clustering in suspended conditions. Effects of treatment with microtubule depolymerizing and stabilizing drugs were described.

RESULTS

Among cell lines, up to 30% of cells expressed McTNs. Four McTN morphologies (absent, symmetric-short, symmetric-long, tufted) were observed in immortalized cultures as well as ascites. McTN number/length varied with histology according to metastatic potential. Most OCCC overexpressed class III ß-tubulin. OCCC/OSC cell lines exhibited a trend towards more microtubule-stabilizing post-translational modifications of α-tubulin relative to HOSE. Microtubule depolymerizing drugs decreased the number/length of McTNs, confirming that McTNs are composed of tubulin. Cells that failed to form McTNs demonstrated differential expression of α-tubulin- and actin-regulating proteins relative to cells that form McTNs. Cluster formation is more susceptible to microtubule targeting agents in cells that form McTNs, suggesting a role for McTNs in aggregation.

CONCLUSIONS

McTNs likely participate in key aspects of ovarian cancer metastasis. McTNs represent a new therapeutic target for this disease that could refine therapies, including intraperitoneal drug delivery.

Harnessing chlorin e6 loaded by functionalized iron oxide nanoparticles linked with glucose for target photodynamic therapy and improving of the immunogenicity of lung cancer

BACKGROUND

Non-small-cell lung cancer (NSCLC) is the most common malignant lung tumor and is difficult to be eradicated due to its immunosuppressive microenvironment. Chlorin e6 (Ce6)-mediated photodynamic therapy (PDT) could improve immunogenicity while destroying malignant tumor cells. However, the clinic application of Ce6-mediated PDT is limited by Ce6's poor water solubility and insufficient accumulation in lung cancer. To address this issue, Ce6 was loaded onto functionalized iron oxide nanoparticles linked with glucose to improve the distribution of Ce6 in lung cancer.

MATERIALS AND RESULTS

The results of transmission electron microscopy (TEM), UV-Vis spectrophotometry, dynamic light scattering and near-infrared (NIR) spectroscopy confirmed the successful preparation of the composites. Confocal and flow cytometry showed IO-PG-GLU-Ce6 significantly enhanced the uptake of Ce6 by lung cancer cells and produced more reactive oxygen species (ROS) under NIR light irradiation. In addition, the detection of cell viability, proliferation and apoptosis indicated IO-PG-GLU-Ce6 achieved stronger photo-toxicity to lung cancer cells. Moreover, IO-PG-GLU-Ce6 treatment effectively damaged the DNA of lung cancer cells and thereby activated STING, up-regulated the expression of IFN-β, HMGB1 and HSP90, indicating augmented immunogenicity of lung cancer cells. Further results of in vivo, organ imaging and tissue fluorescence sections demonstrated IO-PG-GLU-Ce6 significantly improved the distribution of Ce6 in tumor tissues of lung cancer-bearing mice as well. Finally, the findings of in vivo study and immunohistochemistry confirmed the better efficacy of IO-PG-GLU-Ce6. HE staining results of vital organs suggested that the composites were less toxic.

CONCLUSION

In conclusion, Ce6 loaded by functionalized iron oxide nanoparticles linked with glucose exhibited both target photodynamic efficacy and the ability to enhance its immunogenicity in lung cancer. This study provides a promising strategy for augment of the targeting delivery of Ce6 and its mediated photodynamic and immunotherapy.

Autophagy and Apoptosis Induced in U87 MG Glioblastoma Cells by Hypericin-Mediated Photodynamic Therapy Can Be Photobiomodulated with 808 nm Light

Glioblastoma is one of the most aggressive types of tumors. Although few treatment options are currently available, new modalities are needed to improve prognosis. In this context, photodynamic therapy (PDT) is a promising adjuvant treatment modality. In the present work, hypericin-mediated PDT (hypericin-PDT, 2 J/cm²) of U87 MG cells is combined with (2 min, 15 mW/cm² at 808 nm) photobiomodulation (PBM). We observed that PBM stimulates autophagy, which, in combination with PDT, increases the treatment efficacy and leads to apoptosis. Confocal fluorescence microscopy, cytotoxicity assays and Western blot were used to monitor apoptotic and autophagic processes in these cells. Destabilization of lysosomes, mitochondria and the Golgi apparatus led to an increase in lactate dehydrogenase activity, oxidative stress levels, LC3-II, and caspase-3, as well as a decrease of the PKCα and STAT3 protein levels in response to hypericin-PDT subcellular concentration in U87 MG cells. Our results indicate that therapeutic hypericin concentrations can be reduced when PDT is combined with PBM. This will likely allow to reduce the damage induced in surrounding healthy tissues when PBM-hypericin-PDT is used for in vivo tumor treatments.

Photodynamic Therapy for Pancreatic Ductal Adenocarcinoma

Simple Summary

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal of human cancers. Numerous clinical trials evaluating various combinations of chemotherapy and targeted agents and radiotherapy have failed to provide meaningful improvements in survival. A growing number of studies however have indicated that photodynamic therapy (PDT) may be a viable approach for treatment of some pancreatic tumors. PDT, which uses light to activate a photosensitizing agent in target tissue, has seen widespread adoption primarily for dermatological and other applications where superficial light delivery is relatively straightforward. Advances in fiber optic light delivery and dosimetry however have been leveraged to enable PDT even for challenging internal sites, including the pancreas. The aim of this article is to help inform future directions by reviewing relevant literature on the basic science, current clinical status, and potential challenges in the development of PDT as a treatment for PDAC.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal of human cancers. Clinical trials of various chemotherapy, radiotherapy, targeted agents and combination strategies have generally failed to provide meaningful improvement in survival for patients with unresectable disease. Photodynamic therapy (PDT) is a photochemistry-based approach that enables selective cell killing using tumor-localizing agents activated by visible or near-infrared light. In recent years, clinical studies have demonstrated the technical feasibility of PDT for patients with locally advanced PDAC while a growing body of preclinical literature has shown that PDT can overcome drug resistance and target problematic and aggressive disease. Emerging evidence also suggests the ability of PDT to target PDAC stroma, which is known to act as both a barrier to drug delivery and a tumor-promoting signaling partner. Here, we review the literature which indicates an emergent role of PDT in clinical management of PDAC, including the potential for combination with other targeted agents and RNA medicine.

Malignant Ascites in Ovarian Cancer: Cellular, Acellular, and Biophysical Determinants of Molecular Characteristics and Therapy Response

Ascites refers to the abnormal accumulation of fluid in the peritoneum resulting from an underlying pathology, such as metastatic cancer. Among all cancers, advanced-stage epithelial ovarian cancer is most frequently associated with the production of malignant ascites and is the leading cause of death from gynecologic malignancies. Despite decades of evidence showing that the accumulation of peritoneal fluid portends the poorest outcomes for cancer patients, the role of malignant ascites in promoting metastasis and therapy resistance remains poorly understood. This review summarizes the current understanding of malignant ascites, with a focus on ovarian cancer. The first section provides an overview of heterogeneity in ovarian cancer and the pathophysiology of malignant ascites. Next, analytical methods used to characterize the cellular and acellular components of malignant ascites, as well the role of these components in modulating cell biology, are discussed. The review then provides a perspective on the pressures and forces that tumors are subjected to in the presence of malignant ascites and the impact of physical stress on therapy resistance. Treatment options for malignant ascites, including surgical, pharmacological and photochemical interventions are then discussed to highlight challenges and opportunities at the interface of drug discovery, device development and physical sciences in oncology.

Efficient Delivery of Chlorin e6 by Polyglycerol-Coated Iron Oxide Nanoparticles with Conjugated Doxorubicin for Enhanced Photodynamic Therapy of Melanoma

Chlorin e6 (Ce6) is a promising photosensitizer for tumor photodynamic therapy (PDT). However, the efficacy of Ce6 PDT is limited by Ce6's poor water solubility, rapid blood clearance, and inadequate accumulation in the tumor tissue. This problem is tackled in this work, wherein functionalized superparamagnetic iron oxide nanoparticles (IO-NPs) were used as carriers to deliver Ce6 to melanoma. The IO-NPs were coated with polyglycerol (PG) to afford good aqueous solubility. The chemotherapeutic agent doxorubicin (DOX) was attached to the PG coating via the hydrazone bond to afford affinity to the cell membrane and thereby promote the cell uptake. The hydrophobic nature of DOX also induced the aggregation of IO-NPs to form nanoclusters. Ce6 was then loaded onto the IO nanoclusters through physical adsorption and coordination with surface iron atoms, yielding the final composites IO-PG-DOX-Ce6. In vitro experiments showed that IO-PG-DOX-Ce6 markedly increased Ce6 uptake in mouse melanoma cells, leading to much-enhanced photocytotoxicity characterized by intensified reactive oxygen species production, loss of viability, DNA damage, and stimulation of tumor cell immunogenicity. In vivo experiments corroborated the in vitro findings and demonstrated prolonged blood clearance of IO-PG-DOX-Ce6. Importantly, IO-PG-DOX-Ce6 markedly increased the Ce6 distribution and retention in mouse subcutaneous melanoma grafts and significantly improved the efficacy of Ce6-mediated PDT. No apparent vital organ damage was observed at the same time. In conclusion, the IO-PG-DOX NPs provide a simple and safe delivery platform for efficient tumor enrichment of Ce6, thereby enhancing antimelanoma PDT.

Photodynamic Therapy for the Treatment and Diagnosis of Cancer-A Review of the Current Clinical Status

Photodynamic therapy (PDT) has been used as an anti-tumor treatment method for a long time and photosensitizers (PS) can be used in various types of tumors. Originally, light is an effective tool that has been used in the treatment of diseases for ages. The effects of combination of specific dyes with light illumination was demonstrated at the beginning of 20th century and novel PDT approaches have been developed ever since. Main strategies of current studies are to reduce off-target effects and improve pharmacokinetic properties. Given the high interest and vast literature about the topic, approval of PDT as the first drug/device combination by the FDA should come as no surprise. PDT consists of two stages of treatment, combining light energy with a PS in order to destruct tumor cells after activation by light. In general, PDT has fewer side effects and toxicity than chemotherapy and/or radiotherapy. In addition to the purpose of treatment, several types of PSs can be used for diagnostic purposes for tumors. Such approaches are called photodynamic diagnosis (PDD). In this Review, we provide a general overview of the clinical applications of PDT in cancer, including the diagnostic and therapeutic approaches. Assessment of PDT therapeutic efficacy in the clinic will be discussed, since identifying predictors to determine the response to treatment is crucial. In addition, examples of PDT in various types of tumors will be discussed. Furthermore, combination of PDT with other therapy modalities such as chemotherapy, radiotherapy, surgery and immunotherapy will be emphasized, since such approaches seem to be promising in terms of enhancing effectiveness against tumor. The combination of PDT with other treatments may yield better results than by single treatments. Moreover, the utilization of lower doses in a combination therapy setting may cause less side effects and better results than single therapy. A better understanding of the effectiveness of PDT in a combination setting in the clinic as well as the optimization of such complex multimodal treatments may expand the clinical applications of PDT.

Recent advances in regenerative medicine strategies for cancer treatment

Cancer stands as one of the most leading causes of death worldwide, while one of the most significant challenges in treating it is revealing novel alternatives to predict, diagnose, and eradicate tumor cell growth. Although various methods, such as surgery, chemotherapy, and radiation therapy, are used today to treat cancer, its mortality rate is still high due to the numerous shortcomings of each approach. Regenerative medicine field, including tissue engineering, cell therapy, gene therapy, participate in cancer treatment and development of cancer models to improve the understanding of cancer biology. The final intention is to convey fundamental and laboratory research to effective clinical treatments, from the bench to the bedside. Proper interpretation of research attempts helps to lessen the burden of treatment and illness for patients. The purpose of this review is to investigate the role of regenerative medicine in accelerating and improving cancer treatment. This study examines the capabilities of regenerative medicine in providing novel cancer treatments and the effectiveness of these treatments to clarify this path as much as possible and promote advanced future research in this field.

Photodynamic Priming Modulates Endothelial Cell-Cell Junction Phenotype for Light-activated Remote Control of Drug Delivery

The blood-brain barrier (BBB) remains a major obstacle for drug delivery to the central nervous system. In particular, the tight and adherens junctions that join the brain capillary endothelial cells limit the diffusion of various molecules from the bloodstream into the brain. Photodynamic priming (PDP) is a non-cytotoxic modality that involves light activation of photosensitizers to photochemically modulate nearby molecules without killing the cells. Here we investigate the effects of sub-lethal photochemistry on junction phenotype (i.e., continuous, punctate, or perpendicular), as well as the BBB permeability in a transwell model of human brain microvascular endothelial cells (HBMECs). We showed that PDP decreases the continuous junction architecture by ~20%, increases the perpendicular junction architecture by ~40%, and has minimal impact on cell morphology in HBMECs. Furthermore, transwell permeability assay revealed that PDP improves the HBMEC permeability to dextran or nanoliposomes by up to 30-fold for 6-9 days. These results suggest that PDP could safely reverse the mature brain endothelial junctions without killing the HBMECs. This study not only emphasizes the critical roles of PDP in the modulation junction phenotype, but also highlights the opportunity to further develop PDP-based combinations that opens the cerebrum endothelium for enhanced drug transporter across the BBB.

Polyethylene glycol-coated ultrasmall superparamagnetic iron oxide nanoparticles-coupled sialyl Lewis X nanotheranostic platform for nasopharyngeal carcinoma imaging and photothermal therapy

Background

Nasopharyngeal carcinoma (NPC) is a type of head and neck malignant tumor with a high incidence in specific regional distribution, and its traditional therapies face some challenges. It has become an urgent need to seek new therapeutic strategies without or with low toxicity and side effects. At present, more and more researchers has been attracting attention by nanotheranostic platform. Therefore, our team synthesized the polyethylene glycol-coated ultrasmall superparamagnetic iron oxide nanoparticles-coupled sialyl Lewis X (USPIO-PEG-sLe^x) nanotheranostic platform with high temperature pyrolysis.

Results

The USPIO-PEG-sLe^x nanoparticles had excellent photothermal conversion property, and the temperature of USPIO-PEG-sLe^x nanoparticles solution increased with its concentration and power density of near-infrared (NIR) on 808 nm wavelengths. Five USPIO-PEG-sLe^x nanoparticles with different concentrations of 0 mg/ml, 0.025 mg/ml, 0.05 mg/ml, 0.1 mg/ml and 0.2 mg/ml were prepared. The biological toxicity results showed that the viability of NPC 5-8F cells is related to the concentration of USPIO-PEG-sLe^x nanoparticles and the culture time (P < 0.001). The results of photothermal therapy (PTT) in vitro indicated that the viability of 5-8F cells decreased significantly with the concentration of USPIO-PEG-sLe^x nanoparticles increases (P < 0.001), and the viability of NPC 5-8F cells were 91.04% ± 5.20%, 77.83% ± 3.01%, 73.48% ± 5.55%, 59.50% ± 10.98%, 17.11% ± 3.14%, respectively. The USPIO-PEG-sLe^x nanoparticles could target the tumor area, and reduce the T2* value of tumor tissue. The T2* values of tumor pre- and post-injection were 30.870 ± 5.604 and 18.335 ± 4.351, respectively (P < 0.001). In addition, USPIO-PEG-sLe^x nanoparticles as a photothermal agent for PTT could effectively inhibit tumor progression. The ratio of volume change between tail vein injection group, control group, nanoparticles without laser irradiation group and blank group after 5 treatments were 3.04 ± 0.57, 5.80 ± 1.06, 8.09 ± 1.96, 7.89 ± 2.20, respectively (P < 0.001).

Conclusions

Our synthesized USPIO-PEG-sLe^x nanotheranostic platform, and it may be become a new strategy for the treatment of NPC.

Graphic Abstract

Photodestruction of Stromal Fibroblasts Enhances Tumor Response to PDT in 3D Pancreatic Cancer Coculture Models

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal of human cancers. The dismal response of PDAC to virtually all therapeutics is associated, in part, with a characteristically dense fibrotic stroma. This stroma not only acts as a barrier to drug perfusion, but also promotes tumor survival through paracrine crosstalk and biophysical interactions. Photodynamic therapy (PDT) is being explored for PDAC treatment, though the impact of tumor-promoting stromal crosstalk on PDT response in PDAC is not well-characterized. The current study assesses the effect of tumor-stroma interactions on response to PDT or chemotherapy in heterocellular 3D cocultures using PDAC cells and two different fibroblastic cell types (pancreatic stellate cells, PSCs, and a normal human fibroblast cell line, MRC5) embedded in extracellular matrix (ECM). While stromal fibroblasts promote resistance to chemotherapy as expected, PDAC 3D nodules in coculture with fibroblasts exhibit increased response to PDT relative to homotypic cultures. These results point to the potential for PDT to overcome tumor-promoting stromal interactions associated with poor therapeutic response in PDAC.

Plasmonic Hot-Electron Reactive Oxygen Species Generation: Fundamentals for Redox Biology

For decades, the possibility to generate Reactive Oxygen Species (ROS) in biological systems through the use of light was mainly restricted to the photodynamic effect: the photoexcitation of molecules which then engage in charge- or energy-transfer to molecular oxygen (O2) to initiate ROS production. However, the classical photodynamic approach presents drawbacks, like per se chemical reactivity of the photosensitizing agent or fast molecular photobleaching due to in situ ROS generation, to name a few. Recently, a new approach, which promises many advantages, has entered the scene: plasmon-driven hot-electron chemistry. The effect takes advantage of the photoexcitation of plasmonic resonances in metal nanoparticles to induce a new cohort of photochemical and redox reactions. These metal photo-transducers are considered chemically inert and can undergo billions of photoexcitation rounds without bleaching or suffering significant oxidative alterations. Also, their optimal absorption band can be shape- and size-tailored in order to match any of the near infrared (NIR) biological windows, where undesired absorption/scattering are minimal. In this mini review, the basic mechanisms and principal benefits of this light-driven approach to generate ROS will be discussed. Additionally, some significant experiments in vitro and in vivo will be presented, and tentative new avenues for further research will be advanced.

Mechanisms for Tuning Engineered Nanomaterials to Enhance Radiation Therapy of Cancer

Engineered nanomaterials that produce reactive oxygen species on exposure to X- and gamma-rays used in radiation therapy offer promise of novel cancer treatment strategies. Similar to photodynamic therapy but suitable for large and deep tumors, this new approach where nanomaterials acting as sensitizing agents are combined with clinical radiation can be effective at well-tolerated low radiation doses. Suitably engineered nanomaterials can enhance cancer radiotherapy by increasing the tumor selectivity and decreasing side effects. Additionally, the nanomaterial platform offers therapeutically valuable functionalities, including molecular targeting, drug/gene delivery, and adaptive responses to trigger drug release. The potential of such nanomaterials to be combined with radiotherapy is widely recognized. In order for further breakthroughs to be made, and to facilitate clinical translation, the applicable principles and fundamentals should be articulated. This review focuses on mechanisms underpinning rational nanomaterial design to enhance radiation therapy, the understanding of which will enable novel ways to optimize its therapeutic efficacy. A roadmap for designing nanomaterials with optimized anticancer performance is also shown and the potential clinical significance and future translation are discussed.

Vascular and extracellular matrix remodeling by physical approaches to improve drug delivery at the tumor site

INTRODUCTION

Modern comprehensive studies of tumor microenvironment changes allowed scientists to develop new and more efficient strategies that will improve anticancer drug delivery on site. The tumor microenvironment, especially the dense extracellular matrix, has a recognized capability to hamper the penetration of conventional drugs. Development and co-applications of strategies aiming at remodeling the tumor microenvironment are highly demanded to improve drug delivery at the tumor site in a therapeutic prospect.

AREAS COVERED

Increasing indications suggest that classical physical approaches such as exposure to ionizing radiations, hyperthermia or light irradiation, and emerging ones as sonoporation, electric field or cold plasma technology can be applied as standalone or associated strategies to remodel the tumor microenvironment. The impacts on vasculature and extracellular matrix remodeling of these physical approaches will be discussed with the goal to improve nanotherapeutics delivery at the tumor site.

EXPERT OPINION

Physical approaches to modulate vascular properties and remodel the extracellular matrix are of particular interest to locally control and improve drug delivery and thus increase its therapeutic index. They are particularly powerful as adjuvant to nanomedicine delivery; the development of these technologies could have extremely widespread implications for cancer treatment.[Figure: see text].

Depth-resolved imaging of photosensitizer in the rodent brain using fluorescence laminar optical tomography

SIGNIFICANCE

Previous studies have been performed to image photosensitizers in certain organs and tumors using fluorescence laminar optical tomography. Currently, no work has yet been published to quantitatively compare the signal compensation of fluorescence laminar optical tomography with two-dimensional (2-D) imaging in tissues.

AIM

The purpose of this study is to quantify the benefit that fluorescence laminar optical tomography holds over 2-D imaging. We compared fluorescence laminar optical tomography with maximum intensity projection imaging to simulate 2-D imaging, as this would be the most similar and stringent comparison.

APPROACH

A capillary filled with a photosensitizer was placed in a phantom and ex vivo rodent brains, with fluorescence laminar optical tomography and maximum intensity projection images obtained. The signal loss in the Z direction was quantified and compared to see which methodology could compensate better for signal loss caused by tissue attenuation.

RESULTS

The results demonstrated that we can reconstruct a capillary filled with benzoporphyrin derivative photosensitizers faithfully in phantoms and in ex vivo rodent brain tissues using fluorescence laminar optical tomography. We further demonstrated that we can better compensate for signal loss when compared with maximum intensity projection imaging.

CONCLUSIONS

Using fluorescence laminar optical tomography (FLOT), one can compensate for signal loss in deeper parts of tissue when imaging in ex vivo rodent brain tissue compared with maximum intensity projection imaging.

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

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

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.