Synthesis of a novel nanobioconjugate for targeted photodynamic therapy of colon cancer enhanced with cannabidiol

Actively targeted photodynamic therapy in multicellular colorectal cancer spheroids via functionalised gold nanoparticles

Photodynamic therapy (PDT) holds great potential to overcome limitations associated with common colorectal cancer (CRC) treatment approaches. Targeted photosensitiser (PS) delivery systems using nanoparticles (NPs) with targeting moieties are continually being designed, which are aimed at enhancing PS efficacy in CRC PDT. However, the optimisation of targeted PS delivery systems in most, in vitro PDT studies has been conducted on two dimensional (2D) monolayers cell cultures. In our present study, we developed a nano PS delivery system for in vitro cultured human colorectal three-dimensional multicellular spheroids (3D MCTS). PEGylated gold nanoparticles (PEG-AuNPs) were prepared and attached to ZnPcS4PS and further functionalised with specific CRC targeting anti-Guanylate Cyclase monoclonal antibodies(mAb). The ZnPcS4-AuNP-Anti-GCC Ab (BNC) nanoconjugates were successfully synthesised and their photodynamic effect investigated following exposure to laser irradiation and demonstrated enhanced anticancer effects in Caco-2 cells cultivated as 3D MCTS spheroids. Our findings suggest that targeted BNC nanoconjugates can improve the efficacy of PDT and highlight the potential of 3D MCTS tumour model for evaluating of targeted PDT.

Cannabidiol and Aza-BODIPY Coencapsulation for Photodynamic Therapy Enhancement in Liver Cancer Cells

Photodynamic therapy (PDT) and cannabidiol (CBD) have been explored for their potential in synergistic cancer treatment. In this study, we employed CBD oil as a lipid phase, encapsulated within AZB-I@Lec-T to create lipid-based nanoparticles. Here, CBD oil does two tasks: it acts as a pyroptosis agent to destroy liver cancer cells and as a lipid phase to dissolve the photosensitizer. It was expected that this system would offer synergistic therapy between CBD and PDT better than a single use of each treatment. With a series of in vitro experiments, the nanoparticles exhibited induced apoptosis in 68% of HepG2 cells treated with AZB-I@Lec-T@CBD and near-infrared (NIR)-light irradiation, reducing expression levels of antioxidant defense system genes. Furthermore, both components worked well in a submicromolar range when combined in our formulation. These results highlight the potential for amplifying primary cellular damage with the combination of PDT and CBD encapsulation, providing a promising therapeutic approach for liver cancer treatment guidelines.

Design consideration of phthalocyanines as sensitizers for enhanced sono-photodynamic combinatorial therapy of cancer

Cancer remains one of the diseases with the highest incidence and mortality globally. Conventional treatment modalities have demonstrated threatening drawbacks including invasiveness, non-controllability, and development of resistance for some, including chemotherapy, radiation, and surgery. Sono-photodynamic combinatorial therapy (SPDT) has been developed as an alternative treatment modality which offers a non-invasive and controllable therapeutic approach. SPDT combines the mechanism of action of sonodynamic therapy (SDT), which uses ultrasound, and photodynamic therapy (PDT), which uses light, to activate a sensitizer and initiate cancer eradication. The use of phthalocyanines (Pcs) as sensitizers for SPDT is gaining interest owing to their ability to induce intracellular oxidative stress and initiate toxicity under SDT and PDT. This review discusses some of the structural prerequisites of Pcs which may influence their overall SPDT activities in cancer therapy.

Nanoparticles drug delivery for 5-aminolevulinic acid (5-ALA) in photodynamic therapy (PDT) for multiple cancer treatment: a critical review on biosynthesis, detection, and therapeutic applications

Photodynamic therapy (PDT) is a promising cancer treatment that kills cancer cells selectively by stimulating reactive oxygen species generation with photosensitizers exposed to specific light wavelengths. 5-aminolevulinic acid (5-ALA) is a widely used photosensitizer. However, its limited tumour penetration and targeting reduce its therapeutic efficacy. Scholars have investigated nano-delivery techniques to improve 5-ALA administration and efficacy in PDT. This review summarises recent advances in biological host biosynthetic pathways and regulatory mechanisms for 5-ALA production. The review also highlights the potential therapeutic efficacy of various 5-ALA nano-delivery modalities, such as nanoparticles, liposomes, and gels, in treating various cancers. Although promising, 5-ALA nano-delivery methods face challenges that could impair targeting and efficacy. To determine their safety and biocompatibility, extensive preclinical and clinical studies are required. This study highlights the potential of 5-ALA-NDSs to improve PDT for cancer treatment, as well as the need for additional research to overcome barriers and improve medical outcomes.

Cancer Metabolism: The Role of ROS in DNA Damage and Induction of Apoptosis in Cancer Cells

Cancer is a huge challenge for people worldwide. High reactive oxygen species (ROS) levels are a recognized hallmark of cancer and an important aspect of cancer treatment research. Abnormally elevated ROS levels are often attributable to alterations in cellular metabolic activities and increased oxidative stress, which affects both the development and maintenance of cancer. Moderately high levels of ROS are beneficial to maintain tumor cell genesis and development, while toxic levels of ROS have been shown to be an important force in destroying cancer cells. ROS has become an important anticancer target based on the proapoptotic effect of toxic levels of ROS. Therefore, this review summarizes the role of increased ROS in DNA damage and the apoptosis of cancer cells caused by changes in cancer cell metabolism, as well as various anticancer therapies targeting ROS generation, in order to provide references for cancer therapies based on ROS generation.

Cytotoxic Effects of Combinative ZnPcS4 Photosensitizer Photodynamic Therapy (PDT) and Cannabidiol (CBD) on a Cervical Cancer Cell Line

The most prevalent type of gynecological malignancy globally is cervical cancer (CC). Complicated by tumor resistance and metastasis, it remains the leading cause of cancer deaths in women in South Africa. Early CC is managed by hysterectomy, chemotherapy, radiation, and more recently, immunotherapy. Although these treatments provide clinical benefits, many patients experience adverse effects and secondary CC spread. To minimize this, novel and innovative treatment methods need to be investigated. Photodynamic therapy (PDT) is an advantageous treatment modality that is non-invasive, with limited side effects. The Cannabis sativa L. plant isolate, cannabidiol (CBD), has anti-cancer effects, which inhibit tumor growth and spread. This study investigated the cytotoxic combinative effect of PDT and CBD on CC HeLa cells. The effects were assessed by exposing in vitro HeLa CC-cultured cells to varying doses of ZnPcS₄ photosensitizer (PS) PDT and CBD, with a fluency of 10 J/cm² and 673 nm irradiation. HeLa CC cells, which received the predetermined lowest dose concentrations (ICD₅₀) of 0.125 µM ZnPcS₄ PS plus 0.5 µM CBD to yield 50% cytotoxicity post-laser irradiation, reported highly significant and advantageous forms of cell death. Flow cytometry cell death pathway quantitative analysis showed that only 13% of HeLa cells were found to be viable, 7% were in early apoptosis and 64% were in late favorable forms of apoptotic cell death, with a minor 16% of necrosis post-PDT. Findings suggest that this combined treatment approach can possibly induce primary cellular destruction, as well as limit CC metastatic spread, and so warrants further investigation.

Photodynamic Therapy of Aluminum Phthalocyanine Tetra Sodium 2-Mercaptoacetate Linked to PEGylated Copper-Gold Bimetallic Nanoparticles on Colon Cancer Cells

This work reports for the first time on the synthesis, characterization, and photodynamic therapy efficacy of the novel aluminium (III) chloride 2(3), 9(10), 16(17), 23(24)-tetrakis-(sodium 2-mercaptoacetate) phthalocyanine (AlClPcTS41) when alone and when conjugated to PEGylated copper-gold bimetallic nanoparticles (PEG-CuAuNPs) as photosensitizers on colon cancer cells (Caco-2). The novel AlClPcTS41 was covalently linked to the PEG-CuAuNPs via an amide bond to form AlClPcTS41-PEG-CuAuNPs. The amide bond was successfully confirmed using FTIR while the crystal structures were studied using XRD. The morphological and size variations of the PEG-CuAuNPs and AlClPcTS41-PEG-CuAuNPs were studied using TEM, while the hydrodynamic sizes and polydispersity of the particles were confirmed using DLS. The ground state electron absorption spectra were also studied and confirmed the typical absorption of metallated phthalocyanines and their nanoparticle conjugates. Subsequently, the subcellular uptake, cellular proliferation, and PDT anti-tumor effect of AlClPcTS41, PEG-CuAuNPs, and AlClPcTS41-PEG-CuAuNPs were investigated within in vitro Caco-2 cells. The designed AlClPcTS41 and AlClPcTS41-PEG-CuAuNPs demonstrated significant ROS generation abilities that led to the PDT effect with a significantly decreased viable cell population after PDT treatment. These results demonstrate that the novel AlClPcTS41 and AlClPcTS41-PEG-CuAuNPs had remarkable PDT effects against Caco-2 cells and may trigger apoptosis cell death pathway, indicating the potential of the AlClPcTS41 and AlClPcTS41-PEG-CuAuNPs in enhancing the cytotoxic effect of PDT treatment.

Cannabinoid Photochemistry: An Underexplored Opportunity

Photochemistry is a powerful synthetic tool resulting in the construction of unique substances. Remarkably, photochemistry has been relatively underexplored in the cannabinoid area and represents a valuable opportunity for further discovery.

Photodynamic Therapy Efficacy of Novel Zinc Phthalocyanine Tetra Sodium 2-Mercaptoacetate Combined with Cannabidiol on Metastatic Melanoma

This work reports for the first time on the synthesis, characterization, and photodynamic therapy effect of a novel water-soluble zinc (II) 2(3), 9(10), 16(17), 23(24)-tetrakis-(sodium 2-mercaptoacetate) phthalocyanine (ZnPcTS41), on metastatic melanoma cells (A375) combined with cannabidiol (CBD). The ZnPcTS41 structure was confirmed using FTIR, NMR, MS, and elemental analysis while the electronic absorption spectrum was studied using UV-VIS. The study reports further on the dose-dependent effects of ZnPcTS41 (1-8 µM) and CBD alone (0.3-1.1 µM) at 636 nm with 10 J/cm2 on cellular morphology and viability. The IC50 concentrations of ZnPcTS41 and CBD were found to be 5.3 µM and 0.63 µM, respectively. The cytotoxicity effects of the ZnPcTS41 enhanced with CBD on A375 cells were assessed using MTT cell viability assay, ATP cellular proliferation and inverted light microscopy. Cell death induction was also determined via Annexin V-FITC-PI. The combination of CBD- and ZnPcTS41-mediated PDT resulted in a significant reduction in cell viability (15%***) and an increase in the late apoptotic cell population (25%*). These findings suggest that enhancing PDT with anticancer agents such as CBD could possibly obliterate cancer cells and inhibit tumor recurrence.

Semiconductor quantum dots for photodynamic therapy: Recent advances

Photodynamic therapy is a promising cancer treatment that induces apoptosis as a result of the interactions between light and a photosensitizing drug. Lately, the emergence of biocompatible nanoparticles has revolutionized the prospects of photodynamic therapy (PDT) in clinical trials. Consequently, a lot of research is now being focused on developing non-toxic, biocompatible nanoparticle-based photosensitizers for effective cancer treatments using PDT. In this regard, semiconducting quantum dots have shown encouraging results. Quantum dots are artificial semiconducting nanocrystals with distinct chemical and physical properties. Their optical properties can be fine-tuned by varying their size, which usually ranges from 1 to 10 nm. They present many advantages over conventional photosensitizers, mainly their emission properties can be manipulated within the near IR region as opposed to the visible region by the former. Consequently, low intensity light can be used to penetrate deeper tissues owing to low scattering in the near IR region. Recently, successful reports on imaging and PDT of cancer using carbon (carbon, graphene based) and metallic (Cd based) based quantum dots are promising. This review aims to summarize the development and the status quo of quantum dots for cancer treatment.

Enhancement of Conventional and Photodynamic Therapy for Treatment of Cervical Cancer with Cannabidiol

Cervical cancer (CC) is the fourth most diagnosed cancer in women worldwide. Conventional treatments include surgery, chemo- and radiotherapy, however these are invasive and may cause severe side effects. Furthermore, approximately 70% of late-stage CC patients experience metastasis, due to treatment resistance and limitations. Thus, there is a dire need to investigate alternative therapeutic combination therapies. Photodynamic therapy (PDT) is an alternative CC treatment modality that has been clinically proven to treat primary CC, as well as to limit secondary metastasis. Since PDT is a non-invasive localized treatment, with fewer side effects and lessened resistance to dose repeats, it is considered far more advantageous. However, more clinical trials are required to refine its delivery and dosing, as well as improve its ability to activate specific immune responses to eradicate secondary CC spread. Cannabidiol (CBD) isolates have been shown to exert in vitro CC anticancer effects, causing apoptosis post treatment, as well as inducing specific immune responses, which obstruct tumor invasion and angiogenesis, and so hinder CC metastatic spread. This review paper discusses the current conventional and alternative PDT treatment modalities for CC, as well as their limitations over the last 10 years. It has a particular focus on the combinative administration of CBD with these treatments in order to prevent CC secondary migration and so possibly encourage future research studies to focus on this synergistic effect to eradicate CC.