Mechanisms of curcumin-based photodynamic therapy and its effects in combination with electroporation: An in vitro and molecular dynamics study

Curcumin in Ophthalmology: Mechanisms, Challenges, and Emerging Opportunities

Ocular diseases affecting the anterior and posterior segments of the eye are major causes of global vision impairment. Curcumin, a natural polyphenol, exhibits anti-inflammatory, antioxidant, antibacterial, and neuroprotective properties, making it a promising candidate for ocular therapy. However, its clinical use is hindered by low aqueous solubility, poor bioavailability, and rapid systemic elimination. This review comprehensively highlights advances in curcumin delivery systems aimed at overcoming these challenges. Emerging platforms, including proniosomal gels, transferosomes, and cyclodextrin complexes, have improved solubility, permeability, and ocular retention. Nanoparticle-based carriers, such as hybrid hydrogels and biodegradable nanoparticles, enable sustained release and targeted delivery, supporting treatments for posterior segment diseases like diabetic retinopathy and age-related macular degeneration. For anterior segment conditions, including keratitis and dry eye syndrome, cyclodextrin-based complexes and mucoadhesive systems enhance corneal permeability and drug retention. Mechanistically, curcumin modulates key pathways, such as NF-κB and TLR4, reducing oxidative stress, angiogenesis, and apoptosis. Emerging strategies like photodynamic therapy and neuroprotective approaches broaden their application to eyelid conditions and neuroinflammatory ocular diseases. These advancements address curcumin's pharmacokinetic limitations, supporting its clinical translation into ophthalmic therapies. This work underscores curcumin's potential in ocular disease management and advocates clinical trials to validate its safety, efficacy, and therapeutic relevance.

Amelanotic Melanoma-Biochemical and Molecular Induction Pathways

Amelanotic melanoma (AM) is a subtype of hypomelanotic or completely amelanotic melanoma. AM is a rare subtype of melanoma that exhibits a higher recurrence rate and aggressiveness as well as worse surveillance than typical melanoma. AM shows a dysregulation of melanin production, cell cycle control, and apoptosis pathways. Knowing these pathways has an application in medicine due to targeted therapies based on the inhibiting elements of the abovementioned pathways. Therefore, we summarized and discussed AM biochemical and molecular induction pathways and personalized medicine approaches, clinical management, and future directions due to the fact that AM is relatively rare. AM is commonly misdiagnosed. Hence, the role of biomarkers is becoming significant. Nonetheless, there is a shortage of biomarkers specific to AM. BRAF, NRAS, and c-KIT genes are the main targets of therapy. However, the role of BRAF and KIT in AM varied among studies. BRAF inhibitors combined with MAK inhibitors demonstrate better results. Immune checkpoint inhibitors targeting CTLA-4 combined with a programmed death receptor 1 (PD-1) show better outcomes than separately. Fecal microbiota transplantation may overcome resistance to immune checkpoint therapy of AM. Immune-modulatory vaccines against indoleamine 2,3-dioxygenase (IDO) and PD ligand (PD-L1) combined with nivolumab may be efficient in melanoma treatment.

Advancements in transdermal drug delivery: A comprehensive review of physical penetration enhancement techniques

Transdermal drug administration has grown in popularity in the pharmaceutical research community due to its potential to improve drug bioavailability, compliance among patients, and therapeutic effectiveness. To overcome the substantial barrier posed by the stratum corneum (SC) and promote drug absorption within the skin, various physical penetration augmentation approaches have been devised. This review article delves into popular physical penetration augmentation techniques, which include sonophoresis, iontophoresis, magnetophoresis, thermophoresis, needle-free injection, and microneedles (MNs) Sonophoresis is a technique that uses low-frequency ultrasonic waves to break the skin's barrier characteristics, therefore improving drug transport and distribution. In contrast, iontophoresis uses an applied electric current to push charged molecules of drugs inside the skin, effectively enhancing medication absorption. Magnetophoresis uses magnetic fields to drive drug carriers into the dermis, a technology that has shown promise in aiding targeted medication delivery. Thermophoresis is the regulated heating of the skin in order to improve drug absorption, particularly with thermally sensitive drug carriers. Needle-free injection technologies, such as jet injectors (JIs) and microprojection arrays, offer another option by producing temporary small pore sizes in the skin, facilitating painless and effective drug delivery. MNs are a painless, minimally invasive method, easy to self-administration, as well as high drug bioavailability. This study focuses on the underlying processes, current breakthroughs, and limitations connected with all of these approaches, with an emphasis on their applicability in diverse therapeutic areas. Finally, a thorough knowledge of these physical enhancement approaches and their incorporation into pharmaceutical research has the potential to revolutionize drug delivery, providing more efficient and secure treatment choices for a wide range of health-related diseases.

Nanotherapeutic Intervention in Photodynamic Therapy for Cancer

The clinical need for photodynamic therapy (PDT) has been growing for several decades. Notably, PDT is often used in oncology to treat a variety of tumors since it is a low-risk therapy with excellent selectivity, does not conflict with other therapies, and may be repeated as necessary. The mechanism of action of PDT is the photoactivation of a particular photosensitizer (PS) in a tumor microenvironment in the presence of oxygen. During PDT, cancer cells produce singlet oxygen (¹O₂) and reactive oxygen species (ROS) upon activation of PSs by irradiation, which efficiently kills the tumor. However, PDT's effectiveness in curing a deep-seated malignancy is constrained by three key reasons: a tumor's inadequate PS accumulation in tumor tissues, a hypoxic core with low oxygen content in solid tumors, and limited depth of light penetration. PDTs are therefore restricted to the management of thin and superficial cancers. With the development of nanotechnology, PDT's ability to penetrate deep tumor tissues and exert desired therapeutic effects has become a reality. However, further advancement in this field of research is necessary to address the challenges with PDT and ameliorate the therapeutic outcome. This review presents an overview of PSs, the mechanism of loading of PSs, nanomedicine-based solutions for enhancing PDT, and their biological applications including chemodynamic therapy, chemo-photodynamic therapy, PDT-electroporation, photodynamic-photothermal (PDT-PTT) therapy, and PDT-immunotherapy. Furthermore, the review discusses the mechanism of ROS generation in PDT advantages and challenges of PSs in PDT.

Enhanced Photodynamic Therapy: A Review of Combined Energy Sources

Photodynamic therapy (PDT) has been used in recent years as a non-invasive treatment for cancer, due to the side effects of traditional treatments such as surgery, radiotherapy, and chemotherapy. This therapeutic technique requires a photosensitizer, light energy, and oxygen to produce reactive oxygen species (ROS) which mediate cellular toxicity. PDT is a useful non-invasive therapy for cancer treatment, but it has some limitations that need to be overcome, such as low-light-penetration depths, non-targeting photosensitizers, and tumor hypoxia. This review focuses on the latest innovative strategies based on the synergistic use of other energy sources, such as non-visible radiation of the electromagnetic spectrum (microwaves, infrared, and X-rays), ultrasound, and electric/magnetic fields, to overcome PDT limitations and enhance the therapeutic effect of PDT. The main principles, mechanisms, and crucial elements of PDT are also addressed.

The role of catechin in electroporation of pancreatic cancer cells - Effects on pore formation and multidrug resistance proteins

Catechin is a bioflavonoid known for its anti-cancer properties. In the present study, we combined theoretical and experimental approaches to reveal the potential of catechin application in the electroporation (EP) or electrochemotherapy (ECT) of pancreatic cancer cells. The molecular dynamics simulations were implemented to examine the interactions of catechin with a model of a membrane, its influence on the membrane's thickness, and the impact of the catechin-membrane interaction on the pore formation. The data were confronted with experimental measurement of the threshold electric field required for permeabilization of pancreatic cancer cells to a fluorescent dye YO-PRO-1. Further, we examined the influence of catechin on cell viability following electroporation with cisplatin or calcium ions. Finally, we investigated the catechin impact on four proteins associated with multidrug resistance: P-glycoprotein, MRP1, BCRP, and LRP. We demonstrated that catechin may boost the effects of electroporation through various mechanisms: i) increasing the cell permeability prior to electroporation ii) increasing the electroporation threshold iii) sensitization of cells to chemotherapeutic compounds. We showed that catechin incubation influences mRNA levels and mitigates the immunoreactivity of Pgp, MRP1, BCRP, and LRP but these changes did not translate to the efficacy of electrochemotherapy.

Curcumin Loaded Nanocarriers with Varying Charges Augmented with Electroporation Designed for Colon Cancer Therapy

(1) Background: The size and surface charge are the most significant parameters of nanocarriers that determine their efficiency and potential application. The poor cell uptake of encapsulated drugs is the main limitation in anticancer treatment. The well-defined properties of nanocarriers will enable to target specific tissue and deliver an active cargo. (2) Methods: In the current study, poly(D,L -lactide) (PLA) nanocarriers loaded with curcumin (CUR) and differing surface charge were evaluated for transport efficacy in combination with electroporation (EP) in dependence on the type of cells. The obtained CUR-loaded nanoparticles with diameters ranging from 195 to 334 nm (derived from dynamic light scattering (DLS)) were characterized by atomic force microscopy (AFM) (morphology and shape) and Doppler electrophoresis (ζ-potential) as well as UV-vis spectroscopy (CUR encapsulation efficiency (about 90%) and photobleaching rate). The drug delivery properties of the obtained PLA nanocarriers enhanced by electroporation were assessed in human colon cancer cells (LoVo), excitable normal rat muscle cells (L6), and free of voltage-gated ion channels cells (CHO-K1). CLSM studies, viability, and ROS release were performed to determine the biological effects of nanocarriers. (3) Results: The highest photodynamic activity indicated anionic nanocarriers (1a) stabilized by C₁₂(COONa)₂ surfactant. Nanocarriers were cytotoxic for LoVo cells and less cytotoxic for normal cells. ROS release increased in cancer cells with the increasing electric field intensity, irradiation, and time after EP. Muscle L6 cells were less sensitive to electric pulses. (4) Conclusions: EP stimulation for CUR-PLA nanocarriers transport was considered to improve the regulated and more effective delivery of nanosystems differing in surface charge.

Microparticles vs. Macroparticles as Curcumin Delivery Vehicles: Structural Studies and Cytotoxic Effect in Human Adenocarcinoma Cell Line (LoVo)

This study aimed to characterize the hydrogel micro- and macro-particles designed to deliver curcumin to human colon cancer cells (LoVo). Six series of vehicles based on sodium alginate (micro- and macro-particles, uncoated, coated with chitosan or gelatin) were synthesized. The uncoated microparticles were fabricated using an emulsion-based technique and the uncoated macroparticles with an extrusion technique, with both coupled with ionotropic gelation. The surface morphology of the particles was examined with scanning electron microscopy and the average size was measured. The encapsulation efficiency, moisture content, and swelling index were calculated. The release of curcumin from the particles was studied in an experiment simulating the conditions of the stomach, intestine, and colon. To evaluate the anticancer properties of such targeted drug delivery systems, the cytotoxicity of both curcumin-loaded and unloaded carriers to human colon cancer cells was assessed. The microparticles encapsulated much less of the payload than the macroparticles and released their content in a more prolonged manner. The unloaded carriers were not cytotoxic to LoVo cells, while the curcumin-loaded vehicles impaired their viability-more significantly after incubation with microparticles compared to macroparticles. Gelatin-coated or uncoated microparticles were the most promising carriers but their potential anticancer activity requires further thorough investigation.

Potential of Cyanine Derived Dyes in Photodynamic Therapy

Photodynamic therapy (PDT) is a method of cancer treatment that leads to the disintegration of cancer cells and has developed significantly in recent years. The clinically used photosensitizers are primarily porphyrin, which absorbs light in the red spectrum and their absorbance maxima are relatively short. This review presents group of compounds and their derivatives that are considered to be potential photosensitizers in PDT. Cyanine dyes are compounds that typically absorb light in the visible to near-infrared-I (NIR-I) spectrum range (750-900 nm). This meta-analysis comprises the current studies on cyanine dye derivatives, such as indocyanine green (so far used solely as a diagnostic agent), heptamethine and pentamethine dyes, squaraine dyes, merocyanines and phthalocyanines. The wide array of the cyanine derivatives arises from their structural modifications (e.g., halogenation, incorporation of metal atoms or organic structures, or synthesis of lactosomes, emulsions or conjugation). All the following modifications aim to increase solubility in aqueous media, enhance phototoxicity, and decrease photobleaching. In addition, the changes introduce new features like pH-sensitivity. The cyanine dyes involved in photodynamic reactions could be incorporated into sets of PDT agents.