DNA photocleavage by porphyrin–polyamine conjugates

Shining a Light on Prostate Cancer: Photodynamic Therapy and Combination Approaches

Prostate cancer is a major health concern worldwide, and current treatments, such as surgery, radiation therapy, and chemotherapy, are associated with significant side effects and limitations. Photodynamic therapy (PDT) is a promising alternative that has the potential to provide a minimally invasive and highly targeted approach to treating prostate cancer. PDT involves the use of photosensitizers (PSs) that are activated by light to produce reactive oxygen species (ROS), which can induce tumor cell death. There are two main types of PSs: synthetic and natural. Synthetic PSs are classified into four generations based on their structural and photophysical properties, while natural PSs are derived from plant and bacterial sources. Combining PDT with other therapies, such as photothermal therapy (PTT), photoimmunotherapy (PIT), and chemotherapy (CT), is also being explored as a way to improve its efficacy. This review provides an overview of conventional treatments for prostate cancer, the underlying principles of PDT, and the different types of PSs used in PDT as well as ongoing clinical studies. It also discusses the various forms of combination therapy being explored in the context of PDT for prostate cancer, as well as the challenges and opportunities associated with this approach. Overall, PDT has the potential to provide a more effective and less invasive treatment option for prostate cancer, and ongoing research is aimed at improving its selectivity and efficacy in clinical settings.

Recent Advances in the Synthesis of Polyamine Derivatives and Their Applications

Biogenic polyamines (PAs) are involved in the growth and development of normal cells, and their intracellular concentration is stable. The concentration of PAs in cancer cells is significantly increased to promote and sustain their rapid proliferation. Over the years, synthetic PAs, which differ in their structure, have demonstrated high antitumor activity and are involved in clinical trials. The chemical synthesis of PAs and their conjugates require the correct choice of synthetic pathways-methods for constructing conjugates and the orthogonal protection of amino groups. The most common methods of synthesis of PA conjugates are acylation of regioselectively protected PAs or their alkylation under the conditions of the Fukuyama reaction. One of the most promising methods of PA synthesis is the use of a multicomponent Ugi reaction, which allows various PAs to be obtained in high yields. In this review, we describe and analyze various approaches that are used in the synthesis of polyamines and their conjugates.

An All-in-One Organic Semiconductor for Targeted Photoxidation Catalysis in Hypoxic Tumor

Tumor hypoxia severely limits the therapeutic effects of photodynamic therapy (PDT). Although many methods for oxygen generation exist, substantial safety concerns, spatiotenporal uncontrollability, limited efficacy, and complicated procedures have compromised their practical application. Here, we demonstrate a biocompatiable all-in-one organic semiconductor to provide a photoxidation catalysis mechanism of action. A facile method is developed to produce gram-level C₅ N₂ nanoparticles (NPs)-based organic semiconductor. Under 650 nm laser irradiation, the semiconductor split water to generate O₂ and simultaneously produce singlet oxygen (¹ O₂ ), showing that the photocatalyst for O₂ evolution and the photosensitizer (PS) for ¹ O₂ generation could be synchronously achieved in one organic semiconductor. The inherent nucleus targeting capacity endows it with direct and efficient DNA photocleavage. These findings pave the way for developing organic semiconductor-based cancer therapeutic agents.

Interactions of porphyrins with DNA: A review focusing recent advances in chemical modifications on porphyrins as artificial nucleases

The advance of porphyrins as artificial nucleases along the years have developed a class of compounds having potential therapeutic applications. Being an extrovert of chemistry, a variety of chemical modifications have been done on porphyrin macrocycle in order to improve the spectroscopic properties and to adapt as artificial receptors that can recognize molecules. The last twenty years has witnessed broad research in the arena of porphyrin- DNA interactions and their evolution from simple to more complex entities. In this review, we summarize the recent advances in the porphyrin-based structural modifications, with a specific emphasis on various effects of porphyrin on DNA cleavage potency. We particularly detailed the nuclease activity of cationic and anionic porphyrins, porphyrin dimers and conjugates as well as heme proteins till the third generation porphyrins as artificial nucleases.

Interactions of mono spermine porphyrin derivative with DNAs

In this work, we have characterized the interactions of monospermine porphyrin derivative with calf thymus DNA (ct-DNA) and poly (dG-dC)₂ in both B and Z conformation. By several spectroscopic techniques (UV-vis, electronic circular dichroism and resonance light scattering), the binding modes of monospermine porphyrin derivative with different DNA sequences have been elucidated. In the presence of ct-DNA, the porphyrin binds along the external double helix as well as in the presence of B conformation of poly (dG-dC)₂ . Whilst when the Z form of the poly (dG-dC)₂ is induced, a slight intercalation of the porphyrin between the basis has been detected.

Synthesis and characterization of 5-(4-carboxyphenylspermine)-10,15,20-triphenylporphyrin

We synthetized and characterized a mono spermine porphyrin derivative by NMR, UV-vis and fluorescence spectroscopy. The photophysical properties and the protonation equilibria of 5-(4-carboxyphenylspermine)-10,15,20-triphenylporphyrin have been investigated, showing that porphyrin does not aggregate in acidic solutions, differently from what occurs as soon as the core of the porphyrin is deprotonated. These aggregation processes have been detected by the rising of new fluorescence band and a significant splitting of the Soret band.

Synthesis of meso-(4′-cyanophenyl) porphyrins: efficient photocytotoxicity against A549 cancer cells and their DNA interactions

A facile I(iii)-mediated synthesis of cyanoporphyrins and their significant photocytotoxicity (IC₅₀ = 54 nM) against A549 cancer cell line has been described.

Novel polycarboxylate porphyrins: synthesis, characterization, photophysical properties and preliminary antimicrobial study against Gram-positive bacteria

We describe the synthesis, characterization and photophysical properties of two new polycarboxylic photosensitizers. Owing to their structural design, these two compounds show water solubilities larger than natural carboxylic photosensitizers (e.g., protoporphyrin IX, hematoporphyrin, etc.) and also good singlet oxygen quantum yields. These compounds were tested as photo-antimicrobial agents against Staphylococcus aureus and Bacillus cereus strains. Results reveal that their photocytotoxicities are strongly dependent on their amphiphilic character and more precisely the number and position of the carboxylic acid and mesityl substituents.

Synthesis and in vitro evaluation of BBB permeability, tumor cell uptake, and cytotoxicity of a series of carboranylporphyrin conjugates

A series of tri[(p-carboranylmethylthio)tetrafluorophenyl]porphyrin conjugates of linear and branched polyamines, glucose, arginine, tri(ethylene glycol), and Tyr-D-Arg-Phe-β-Ala (YRFA) peptide were synthesized. These conjugates were investigated for their BBB permeability in human hCMEC/D3 brain endothelial cells, and their cytotoxicity and uptake were assessed using human glioma T98G cells. For comparison purposes, a symmetric tetra[(p-carboranylmethylthio)tetrafluorophenyl]porphyrin was also synthesized, and its crystal structure was obtained. All porphyrin conjugates show low dark cytotoxicity (IC50>400 μM) and low phototoxicity (IC50>100 μM at 1.5 J/cm2) toward T98G cells. All conjugates were efficiently taken up by T98G cells, particularly the cationic polyamine and arginine conjugates, and were localized in multiple cellular organelles, including mitochondria and lysosomes. All compounds showed relatively low in vitro BBB permeability compared with that of lucifer yellow because of their higher molecular weight, hydrophobicity, and tendency for aggregation in solution. Within this series, the branched polyamine and YRFA conjugates showed the highest permeability coefficient, whereas the glucose conjugate showed the lowest permeability coefficient.

Synthesis and cellular studies of polyamine conjugates of a mercaptomethyl-carboranylporphyrin

Seven polyamine conjugates of a tri(p-carboranylmethylthio)tetrafluorophenylporphyrin were prepared in high yields by sequential substitution of the p-phenyl fluoride of tetrakis(pentafluorophenyl)porphyrin (TPPF), and investigated as boron delivery agents for boron neutron capture therapy (BNCT). The polyamines used were derivatives of the natural-occurring spermine with different lengths of the carbon chains, terminal primary amine groups and, in two of the conjugates, additional aminoethyl moieties. A tri(polyethylene glycol) conjugate was also synthesized for comparison purposes. The polyamine conjugates showed low dark cytotoxicity (IC(50) >400 μM) and low phototoxicity (IC(50) >40 μM at 1.5 J/cm(2)). All polyamine conjugates, with one exception, showed higher uptake into human glioma T98G cells (up to 12-fold) than the PEG conjugate, and localized preferentially in the cell ER, Golgi and the lysosomes. Our results show that spermine derivatives can serve as effective carriers of boronated porphyrins for the BNCT of tumors.

Photodynamic inactivation of mammalian viruses and bacteriophages

Photodynamic inactivation (PDI) has been used to inactivate microorganisms through the use of photosensitizers. The inactivation of mammalian viruses and bacteriophages by photosensitization has been applied with success since the first decades of the last century. Due to the fact that mammalian viruses are known to pose a threat to public health and that bacteriophages are frequently used as models of mammalian viruses, it is important to know and understand the mechanisms and photodynamic procedures involved in their photoinactivation. The aim of this review is to (i) summarize the main approaches developed until now for the photodynamic inactivation of bacteriophages and mammalian viruses and, (ii) discuss and compare the present state of the art of mammalian viruses PDI with phage photoinactivation, with special focus on the most relevant mechanisms, molecular targets and factors affecting the viral inactivation process.