Current Targets and Bioconjugation Strategies in Photodynamic Diagnosis and Therapy of Cancer

Characterization and efficacy of C60 nano-photosensitive drugs in colorectal cancer treatment

BACKGROUND

Fullerenes C60 shows great potential for drug transport. C60 generates large amounts of singlet oxygen upon photoexcitation, which has a significant inhibitory effect on tumor cells, so the photosensitive properties of C60 were exploited for photodynamic therapy of tumors by laser irradiation.

METHODS

In this study, C60-NH2 was functionalized by introducing amino acids on the surface of C60, coupled with 5-FU to obtain C60 amino acid-derived drugs (C60AF, C60GF, C60LF), and activated photosensitive drugs (C60AFL, C60GFL, C60LFL) were obtained by laser irradiation. The C60 nano-photosensitive drugs were characterized in various ways, and the efficacy and safety of C60 nano-photosensitive drugs were verified by cellular experiments and animal experiments. Bioinformatics methods and cellular experiments were used to confirm the photosensitive drug targets and verify the therapeutic targets with C60AF.

RESULTS

Photosensitised tumor-targeted drug delivery effectively crosses cell membranes, leads to more apoptotic cell death, and provides higher anti-tumor efficacy and safety in vitro and in vivo colorectal cancer pharmacodynamic assays compared to free 5-FU.C60 photosensitized drug promotes tumor killing by inhibiting the colorectal cancer FLOR1 tumor protein target, with no significant toxic effects on normal organs.

CONCLUSION

C60 photosensitized drug delivery systems are expected to improve efficacy and reduce side effects in the future treatment of colorectal cancer. Further and better development and design of drugs and vectors for colorectal cancer therapy.

Verteporfin fluorescence in antineoplastic-treated pancreatic cancer cells found concentrated in mitochondria

BACKGROUND

Traditional treatments for pancreatic cancer (PC) are inadequate. Photodynamic therapy (PDT) is non-invasive, and proven safe to kill cancer cells, including PC. However, the mitochondrial concentration of the photosensitizer, such as verteporfin, is key.

AIM

To investigate the distribution of fluorescence of verteporfin in PC cells treated with antitumor drugs, post-PDT.

METHODS

Workable survival rates of PC cells (AsPC-1, BxPC-3) were determined with chemotherapy [doxorubicin (DOX) and gemcitabine (GEM)] and non-chemotherapy [sirolimus (SRL) and cetuximab (CTX)] drugs in vitro, with or without verteporfin, as measured via MTT, flow cytometry, and laser confocal microscopy. Reduced cell proliferation was associated with GEM that was more enduring compared with DOX. Confocal laser microscopy allowed observation of GEM- and verteporfin-treated PC cells co-stained with 4',6-diamidino-2-phenylindole and MitoTracker Green to differentiate living and dead cells and subcellular localization of verteporfin, respectively.

RESULTS

Cell survival significantly dropped upon exposure to either chemotherapy drug, but not to SRL or CTX. Both cell lines responded similarly to GEM. The intensity of fluorescence was associated with the concentration of verteporfin. Additional experiments using GEM showed that survival rates of the PC cells treated with 10 μmol/L verteporfin (but not less) were significantly lower relative to nil verteporfin. Living and dead stained cells treated with GEM were distinguishable. After GEM treatment, verteporfin was observed primarily in the mitochondria.

CONCLUSION

Verteporfin was observed in living cells. In GEM -treated human PC cells, verteporfin was particularly prevalent in the mitochondria. This study supports further study of PDT for the treatment of PC after neoadjuvant chemotherapy.

Precise Photodynamic Therapy by Midkine Nanobody-Engineered Nanoparticles Remodels the Microenvironment of Pancreatic Ductal Adenocarcinoma and Potentiates the Immunotherapy

Pancreatic ductal adenocarcinoma (PDAC) is notorious for its resistance against chemotherapy and immunotherapy due to its dense desmoplastic and immunosuppressive tumor microenvironment (TME). Traditional photodynamic therapy (PDT) was also less effective for PDAC owing to poor selectivity, insufficient penetration, and accumulation of photosensitizers in tumor sites. Here, we designed a light-responsive novel nanoplatform targeting the TME of PDAC through tumor-specific midkine nanobodies (Nbs), which could efficiently deliver semiconducting polymeric nanoparticles (NPs) to the TME of PDAC and locally produce abundant reactive oxygen species (ROS) for precise photoimmunotherapy. The synthesized nanocomposite can not only achieve multimodal imaging of PDAC tumors (fluorescence and photoacoustic imaging) but also lead to apoptosis and immunogenic cell death of tumor cells via ROS under light excitation, ultimately preventing tumor progression and remodeling the immunosuppressive TME with increased infiltration of T lymphocytes. Combined with a PD-1 checkpoint blockade, the targeted PDT platform showed the best antitumor performance and markedly extended mice survival. Conclusively, this work integrating Nbs with photodynamic NPs provides a novel strategy to target formidable PDAC to achieve tumor suppression and activate antitumor immunity, creating possibilities for boosting efficacy of immunotherapy for PDAC tumors through the combination with precise local PDT.

Advanced Light Source Technologies for Photodynamic Therapy of Skin Cancer Lesions

Photodynamic therapy (PDT) is an increasingly popular dermatological treatment not only used for life-threatening skin conditions and other tumors but also for cosmetic purposes. PDT has negligible effects on underlying functional structures, enabling tissue regeneration feasibility. PDT uses a photosensitizer (PS) and visible light to create cytotoxic reactive oxygen species, which can damage cellular organelles and trigger cell death. The foundations of modern photodynamic therapy began in the late 19th and early 20th centuries, and in recent times, it has gained more attention due to the development of new sources and PSs. This review focuses on the latest advancements in light technology for PDT in treating skin cancer lesions. It discusses recent research and developments in light-emitting technologies, their potential benefits and drawbacks, and their implications for clinical practice. Finally, this review summarizes key findings and discusses their implications for the use of PDT in skin cancer treatment, highlighting the limitations of current approaches and providing insights into future research directions to improve both the efficacy and safety of PDT. This review aims to provide a comprehensive understanding of PDT for skin cancer treatment, covering various aspects ranging from the underlying mechanisms to the latest technological advancements in the field.

The bromoporphyrins as promising anti-tumor photosensitizers in vitro

The synthesis of ideal photosensitizers (PSs) is considered to be the most significant bottleneck in photodynamic therapy (PDT). To discover novel PSs with excellent photodynamic anti-tumor activities, a series of novel photosensitizers 5,15-diaryl-10,20-dibromoporphyrins (I_1-6) were synthesized by a facile method. Compared with hematoporphyrin monomethyl ether (HMME) as the representative porphyrin-based photosensitizers, it is found that not only the longest absorption wavelength of all compounds was red-shifted to therapeutic window (660 nm) of photodynamic therapy, but also the singlet oxygen quantum yields were significantly increased. Furthermore, all compounds exhibited lower dark toxicity (except I₂) and stronger phototoxicity (except I₄) against Eca-109 tumor cells than HMME. Among them, I₃ possessed the highest singlet oxygen quantum yield (Φ_Δ = 0.205), the lower dark toxicity and the strongest phototoxicity (IC₅₀ = 3.5 μM) in vitro. The findings indicated the compounds I₃ had the potential to become anti-tumor agents for PDT.

Development and Recent Advances in Lysine and N-Terminal Bioconjugation for Peptides and Proteins

The demand for creation of protein diversity and regulation of protein function through native protein modification and post-translational modification has ignited the development of selective chemical modification methods for peptides and proteins. Chemical bioconjugation offers selective functionalization providing bioconjugates with desired properties and functions for diverse applications in chemical biology, medicine, and biomaterials. The amino group existing at the lysine residue and N-terminus of peptides and proteins has been extensively studied in bioconjugation because of its good nucleophilicity and high surface exposure. Herein, we review the development of chemical methods for modification of the amino groups on lysine residue and N-terminus featuring excellent selectivity, mild reaction conditions, short reaction time, high conversion, biocompatibility, and preservation of protein integrity. This review is organized based on the chemoselectivity and site-selectivity of the chemical bioconjugation reagents to the amino acid residues aiming to provide guidance for the selection of appropriate bioconjugation methods.

A Selenium-Substituted Heptamethine Cyanine Photosensitizer for Near-Infrared Photodynamic Therapy

Photodynamic therapy (PDT) is a relatively safe approach to cancer treatment without significant systemic side effects or drug resistance. However, the current PDT efficiency is unsatisfactory due to the lack of near-infrared (NIR) photosensitizers. Heptamethine cyanine (Cy7) dyes are well-known NIR fluorophores and are also used as photosensitizers. But their singlet oxygen quantum yields (Φ_Δ ) are not ideal. Herein, we developed an NIR photosensitizer with a long-lived excited triplet state (τ=4.3 μs) by introducing a selenium atom into the structure of a Cy7 dye. The new NIR photosensitizer exhibits a significantly high singlet oxygen quantum yield (Φ_Δ =0.11). Its good PDT effect was demonstrated in the living cells. Considering that the selenium-substituted photosensitizer has a very low dark cytotoxicity and good chemical stability, we conclude that it will have a promising future in biomedical and clinical applications.

Phenol- and resorcinol-appended metallocorroles and their derivatization with fluorous tags

Boron tribromide-mediated demethylation of rhenium-oxo and gold meso-tris(4-methoxyphenyl)corrole and meso-tris(3,5-dimethoxyphenylcorrole), M[TpOMePC] and M[T(3,5-OMe)PC] (M = ReO, Au), have yielded the corresponding phenol- and resorcinol-appended metallocorroles, M[TpOHPC] and M[T(3,5-OH)PC], in good yields. The latter compounds proved insoluble in dichloromethane and chloroform but soluble in THF. The M[T(3,5-OH)PC] derivatives also proved moderately soluble in 0.05 M aqueous KOH. Unlike oxidation-prone aminophenyl-substituted corroles, the phenol- and resorcinol-appended metallocorroles could be readily handled in air without special precautions. The phenolic metallocorroles could be readily alkylated with 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-heptadecafluoroundecyl iodide ("FtI") to afford the fluorous-tagged metallocorroles M[TpOFtPC] and M[T(3,5-OFt)PC] in > 90% yields. The simplicity of the synthetic protocols promise a wide range of phenolic and fluorous-tagged porphyrin analogues with potential applications to diverse fields such as sensors, catalysis, and photodynamic therapy, among others.

Tissue factor as a new target for tumor therapy-killing two birds with one stone: a narrative review

Background and Objective

Cancer is an important disease and can occur anywhere in the body. It is caused by uncontrolled cell growth that spreads to other body parts. This study extensively investigated the transmembrane receptor tissue factor (TF), which is the key motivator of the clotting cascade and plays an essential role in cancer-associated coagulation. TF is considered to be aberrantly expressed in various tumors and appears to promote tumor angiogenesis and metastasis. Therefore, this study was performed to explain the pathological characteristics of TF expression and to discuss future cancer therapies that target TF.

Methods

We extensively reviewed the literature on TF published in PubMed, and discussed the effect of TF on tumor progression and TF-targeted therapeutics.

Key Content and Findings

This review aimed to uncover how TFs contribute to tumor progression and cancer-associated thrombosis and summarize TF-based targeted therapy. Multiple functions and mechanisms of the TF in cancer-associated thrombosis and tumor progression were discussed.

Conclusions

The current literature has confirmed that the TF is involved in the hypercoagulable state of tumors and promotes malignant tumors through coagulation-dependent or non-coagulation-dependent pathways. TF-dependent signaling is also involved in divergent cancer progression. Thus, TF-targeted therapeutics could have broad clinical applicability for the treatment of tumors.

Photodynamic Therapy: A Prospective Therapeutic Approach for Viral Infections and Induced Neoplasia

The recent COVID-19 pandemic outbreak and arising complications during treatments have highlighted and demonstrated again the evolving ability of microorganisms, especially viral resistance to treatment as they develop into new and strong strains. The search for novel and effective treatments to counter the effects of ever-changing viruses is undergoing. Although it is an approved procedure for treating cancer, photodynamic therapy (PDT) was first used against bacteria and has now shown potential against viruses and certain induced diseases. PDT is a multi-stage process and uses photosensitizing molecules (PSs) that accumulate in diseased tissues and eradicates them after being light-activated in the presence of oxygen. In this review, studies describing viruses and their roles in disrupting cell regulation mechanisms and signaling pathways and facilitating tumorigenesis were described. With the development of innovative “or smart” PSs through the use of nanoparticles and two-photon excitation, among other strategies, PDT can boost immune responses, inactivate viral infections, and eradicate neoplastic cells. Visualization and monitoring of biological processes can be achieved in real-time with nanomedicines and better tissue penetration strategies. After photodynamic inactivation of viruses, signaling pathways seem to be restored but the underlying mechanisms are still to be elucidated. Light-mediated treatments are suitable to manage both oncogenic viral infections and induced neoplasia.

Targeted Photodynamic Diagnosis and Therapy for Esophageal Cancer: Potential Role of Functionalized Nanomedicine

Esophageal cancer is often diagnosed at the late stage when cancer has already spread and is characterized by a poor prognosis. Therefore, early diagnosis is vital for a better and efficient treatment outcome. Upper endoscopy with biopsy is the standard diagnostic tool for esophageal cancer but is challenging to diagnose at its premalignant stage, while conventional treatments such as surgery, chemotherapy, and irradiation therapy, are challenging to eliminate the tumor. Photodynamic diagnosis (PDD) and therapy (PDT) modalities that employ photosensitizers (PSs) are emerging diagnostic and therapeutic strategies for esophageal cancer. However, some flaws associated with the classic PSs have limited their clinical applications. Functionalized nanomedicine has emerged as a potential drug delivery system to enhance PS drug biodistribution and cellular internalization. The conjugation of PSs with functionalized nanomedicine enables increased localization within esophageal cancer cells due to improved solubility and stability in blood circulation. This review highlights PS drugs used for PDD and PDT for esophageal cancer. In addition, it focuses on the various functionalized nanomedicine explored for esophageal cancer and their role in targeted PDD and PDT for diagnosis and treatment.

Photodynamic Therapy: A Compendium of Latest Reviews

Photodynamic therapy (PDT) is a promising therapy against cancer. Even though it has been investigated for more than 100 years, scientific publications have grown exponentially in the last two decades. For this reason, we present a brief compendium of reviews of the last two decades classified under different topics, namely, overviews, reviews about specific cancers, and meta-analyses of photosensitisers, PDT mechanisms, dosimetry, and light sources. The key issues and main conclusions are summarized, including ways and means to improve therapy and outcomes. Due to the broad scope of this work and it being the first time that a compendium of the latest reviews has been performed for PDT, it may be of interest to a wide audience.

Evaluating the mechanisms of action and subcellular localization of ruthenium(II)-based photosensitizers

The identification of ruthenium(II) polypyridyl complexes as photosensitizers in photodynamic therapy (PDT) for the treatment of cancer is progressing rapidly. Due to their favorable photophysical and photochemical properties, Ru(II)-based photosensitizers have absorption in the visible spectrum, can be irradiated via one- and two-photon excitation within the PDT window, and yield potent oxygen-dependent and/or oxygen-independent photobiological activities. Herein, we present a current overview of the mechanisms of action and subcellular localization of Ru(II)-based photosensitizers in the treatment of cancer. These photosensitizers are highlighted from a medicinal chemistry and chemical biology perspective. However, although this field is burgeoning, challenges and limitations remain in the photosensitization strategies and clinical translation.

A Study on Mesoporous Silica Loaded With Novel Photosensitizers HCE6 and Oxaliplatin for the Treatment of Cholangiocarcinoma

Purpose

Cholangiocarcinoma (CCA) is a malignant tumor with a high incidence. The therapeutic effect of conventional chemotherapy and radiotherapy is not obvious. Photodynamic therapy (PDT) is an ideal modality to fight cancer, and the nature of photosensitizer limits its application in clinical therapy. The aim of this study was to explore a novel mode of drug delivery for the intervention of bile duct cancer.

Methods

Oxaliplatin and photosensitizer HCE6 were loaded with mesoporous silica nanoparticles (MSNs) to synthesize Oxaliplatin/HCE6-MSNs (OH-MSNs); the structure of OH-MSNs was characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS), the drug release rate was detected by high performance liquid chromatography; the cellular activity, apoptosis level, and the expression levels of intracellular apoptosis and autophagy-related factors of OH-MSNs on cholangiocarcinoma cells were observed by CCK-8, flow cytometry, colony formation assay, and Western blot; the effects of OH-MSNs on cholangioma growth were observed by mouse tumor formation, immunohistochemistry, and tissue Tunel staining.

Results

The release of OH-MSNs to Oxaliplatin was enhanced under acidic conditions; compared with Oxaliplatin or O-MSNs, OH-MSNs showed more potent killing effects against cholangiocarcinoma cells (P<0.05), and exerted notably inhibitory effects on the activity of cholangiocarcinoma cells (P<0.05), promoted their apoptosis (P<0.05), and greatly facilitated the expression of pro-apoptotic factors and autophagic factors in cholangiocarcinoma cells (P<0.05), and markedly inhibited the expression of anti-apoptotic factors and autophagic inhibitory factors (P<0.05); moreover, OH-MSNs could significantly suppress the growth of mouse cholangiocarcinoma (P<0.05) and induce apoptosis of tumor cells compared with Oxaliplatin or O-MSNs (P<0.05).

Conclusion

MSNs loading greatly increases the killing effect of Oxaliplatin on cholangiocarcinoma cells and upgrades the autophagic level of cholangiocarcinoma cells, while OH-MSNs synthesized by further loading HCE6 have a more apparent killing effect on cholangiocarcinoma cells.

Development of Non-Porous Silica Nanoparticles towards Cancer Photo-Theranostics

Nanoparticles have demonstrated several advantages for biomedical applications, including for the development of multifunctional agents as innovative medicine. Silica nanoparticles hold a special position among the various types of functional nanoparticles, due to their unique structural and functional properties. The recent development of silica nanoparticles has led to a new trend in light-based nanomedicines. The application of light provides many advantages for in vivo imaging and therapy of certain diseases, including cancer. Mesoporous and non-porous silica nanoparticles have high potential for light-based nanomedicine. Each silica nanoparticle has a unique structure, which incorporates various functions to utilize optical properties. Such advantages enable silica nanoparticles to perform powerful and advanced optical imaging, from the in vivo level to the nano and micro levels, using not only visible light but also near-infrared light. Furthermore, applications such as photodynamic therapy, in which a lesion site is specifically irradiated with light to treat it, have also been advancing. Silica nanoparticles have shown the potential to play important roles in the integration of light-based diagnostics and therapeutics, termed "photo-theranostics". Here, we review the recent development and progress of non-porous silica nanoparticles toward cancer "photo-theranostics".