Diamino acid derivatives of PpIX as potential photosensitizers for photodynamic therapy of squamous cell carcinoma and prostate cancer: In vitro studies

Assessment of the Effect of Surface Modification of Metal Oxides on Silver Nanoparticles: Optical Properties and Potential Toxicity

Silver nanoparticles (AgNPs) have garnered significant interest due to their distinctive properties and potential applications. Traditional fabrication methods for nanoparticles often involve high-energy physical conditions and the use of toxic solvents. Various green synthesis approaches have been developed to circumvent these issues and produce environmentally benign nanoparticles. Our study focuses on the green synthesis of AgNPs using L-ascorbic acid and explores the modification of their properties to enhance antibacterial and anticancer effects. This is achieved by coating the nanoparticles with Zinc oxide (ZnO) and Silica oxide (SiO2), which alters their optical properties in the visible spectrum. The synthesized formulations-AgNPs, zinc oxide-silver nanoparticles (Ag@ZnO), and silica oxide-silver nanoparticles (Ag@SiO2) core/shell nanoparticles-were characterized using a suite of physicochemical techniques, including Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), Zeta potential measurement, UV-Vis spectroscopy, Refractive Index Measurements, and Optical Anisotropy Assessment. TEM imaging revealed particle sizes of 11 nm for AgNPs, 8 nm for Ag@ZnO, and 400 nm for Ag@SiO2. The Zeta potential values for Ag@ZnO and Ag@SiO2 were measured at -17.0 ± 5 mV and -65.0 ± 8 mV, respectively. UV-Vis absorption spectra were recorded for all formulations in the 320 nm to 600 nm wavelength range. The refractive index of AgNPs at 404.7 nm was 1.34572, with slight shifts observed for Ag@ZnO and Ag@SiO2 to 1.34326 and 1.37378, respectively. The cytotoxicity of the nanocomposites against breast cancer cell lines (MCF-7) was assessed using the MTT assay. The results indicated that AgNPs and Ag@ZnO exhibited potent therapeutic effects, with IC50 values of 494.00 µg/mL and 430.00 µg/mL, respectively, compared to 4247.20 µg/mL for Ag@SiO2. Additionally, the antibacterial efficacy of AgNPs was significantly enhanced under visible light irradiation. Ag@ZnO demonstrated substantial antibacterial activity both with and without light exposure, while the Ag@SiO2 nanocomposites significantly reduced the inherent antibacterial activity of silver. Conversely, the Ag@ZnO nanocomposites displayed pronounced antibacterial and anticancer activities. The findings suggest that silver-based nanocomposites, particularly Ag@ZnO, could be practical tools in water treatment and the pharmaceutical industry due to their enhanced therapeutic properties.

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.

The biological activities of 5,15-diaryl-10,20-dihalogeno porphyrins for photodynamic therapy

PURPOSE

Esophageal cancer is the most common gastrointestinal tumor and is difficult to be eradicated with conventional treatment. Porphyrin-based photosensitizers (PSs) mediated photodynamic therapy (PDT) could kill tumor cells with less damage to normal cells. As the most widely used porphyrin-based photosensitizer in clinics, Photofrin II has excellent anti-tumor effect. However, it has some disadvantages such as weak absorption at near infrared region, the complexity of components and prolonged skin photosensitivity. Here series novel 5,15-diaryl-10,20-dihalogeno porphyrin derivatives were afforded and evaluated to develop more effective and safer photosensitizers for tumor therapy.

METHODS

The photophysical properties and singlet oxygen generation rates of 5,15-diaryl-10,20-dihalogeno porphyrins (I_1-6, II_1-4) were tested. The cytotoxicity of I_1-6 and II_1-4 were measured by MTT assay. The pathway of cell death was studied by flow cytometry. In vivo photodynamic efficacy of I₃ and II_2-4 in Eca-109 tumor-bearing BABL/c nude mice were measured and histopathological analysis were examined.

RESULTS

5,15-Diaryl-10,20-dihalogeno porphyrins I_1-6 and II_1-4 were synthesized. The longest absorption wavelength of these halogenated porphyrins (λ_max = 660 nm) displayed a red shift around 30 nm compared to the unhalogenated porphyrins PS₁ (λ_max = 630 nm). The singlet oxygen generation rates of I_1-6 and II_1-4 were significantly higher than PS₁ and HMME. All PSs mediated PDT showed obvious cytotoxic effect against Eca-109 cells compared to HMME in vitro and in vivo. Among these PSs, II₄ exhibited appropriate absorption in the phototherapeutic window, higher ¹O₂ generation rate (k = 0.0061 s^-1), the strongest phototoxicity (IC₅₀ = 0.4 μM), lower dark toxicity, high generation of intracellular ROS in Eca-109 cells and excellent photodynamic anti-tumor efficacy in vivo. Besides, cell necrosis was induced by compound II₄ mediated PDT.

CONCLUSION

All new compounds have obvious photodynamic anti-esophageal cancer effects. Among them, the photosensitizer II₄ showed excellent efficacy in vitro and in vivo, which has the potential to become a photodynamic anti-tumor drug.

Design, synthesis and biological evaluation of novel 31-hexyloxy chlorin e6-based 152- or 131-amino acid derivatives as potent photosensitizers for photodynamic therapy

This study aimed to improve the biological effectiveness and pharmacokinetic properties of chlorin e₆, a second-generation photosensitizer (PS), for tumor photodynamic therapy (PDT). Herein, the novel 3¹-hexyloxy chlorin e₆-based 15²- or 13¹-amino acid derivatives 3a, 3b, 3c and 8 were synthesized and their photophysical properties and in vitro bioactivities such as phototoxicity against A549, HeLa and melanoma B16-F10 cells, reactive oxygen species (ROS) production and subcellular localization were evaluated. In addition, preferred target compounds were also investigated for their in vivo pharmacokinetic in SD rats and in vivo antitumor efficacies in C57BL/6 mice bearing melanoma B16-F10 cells. Apparently, simultaneous introduction of amino acid residue and n-hexyloxy chain in chlorin e₆ made a significant improvement in photophysical properties, ROS production, in vitro and in vivo PDT efficacy. Encouragingly, all target compounds showed higher in vitro phototoxicity than Talaporfin, and that 3c (15²-Lys) exhibited strongest phototoxicity and highest dark toxicity/phototoxicity ratio, followed by 8 (13¹-Asp), 3a (15²-Asp) and 3b (15²-Glu). Moreover, in vivo PDT antitumor efficacy of 3a, 3c and 8 was all better than that of Talaporfin, and that both 3c and 8 had stronger PDT antitumor efficiency than 3a. The overall results suggested that these novel 3¹-hexyloxy chlorin e₆-based 15²- or 13¹-amino acid derivatives, especially 3c and 8, might be potential antitumor candidate drugs for clinical treatment of melanoma by PDT.

Chlorin p6-Based Water-Soluble Amino Acid Derivatives as Potent Photosensitizers for Photodynamic Therapy

The development of novel photosensitizer with high phototoxicity, low dark toxicity, and good water solubility is a challenging task for photodynamic therapy (PDT). A series of chlorin p6-based water-soluble amino acid conjugates were synthesized and investigated for antitumor activity. Among them, aspartylchlorin p6 dimethylester (7b) showed highest phototoxicity against melanoma cells with weakest dark toxicity, which was more phototoxic than verteporfin while with less dark toxicity. It also exhibited better in vivo PDT antitumor efficacy on mice bearing B16-F10 tumor than verteporfin. The biological assays revealed that 7b was localized in multiple subcellular organelles and could cause both cell necrosis and apoptosis after PDT in a dose-dependent manner, resulting in more effective cell destruction. As a result, 7b represents a promising photosensitizer for PDT applications because of its strong absorption in the phototherapeutic window, relatively high singlet oxygen quantum yield, highest dark toxicity/phototoxicity ratio, good water solubility, and excellent in vivo PDT antitumor efficacy.

Apoptotic mechanism of MCF-7 breast cells in vivo and in vitro induced by photodynamic therapy with C-phycocyanin

The aim of this study was to investigate the pro-apoptotic mechanism of C-phycocyanin (C-PC)-mediated photodynamic therapy (PDT) in a murine tumor model and cultured MCF-7 cells. The mice were divided into four groups: control, He-Ne laser radiation, C-PC treatment, and C-PC treatment + He-Ne laser radiation. The effects of C-PC and/or laser on immune organs, immunocyte proliferation, tumor genesis, and apoptosis-related proteins expressions were investigated by immunohistochemistry, in situ hybridization, MTT, electron microscope, western blot, and immunofluorescence assay. The results showed that He-Ne laser treatment alone showed marginal effects. In C-PC-treated mice, the weight of immune organs, proliferation of immunocytes, and expression of pro-apoptotic Fas protein were increased, whereas the tumor weight and the expressions of anti-apoptotic proteins (NF-kappaB and P53) and CD44 mRNA were comparatively decreased. In vitro, C-PC was able to inhibit MCF-7 cell proliferation and cause ultrastructural changes including microvilli loss, formation of membrane blebs, and chromatin condensation. Moreover, C-PC treatment could activate caspase-9 expression, induce cytochrome c release, and downregulate Bcl-2 expression. When combined with He-Ne laser irradiation, the effects of C-PC treatment were further enhanced. Facilitating the apoptosis signals transduction and finally leading to the apoptosis of MCF-7 cells may be the mechanism of the anti-tumor activities of C-PC-mediated PDT.

Photodynamic therapy with 5-aminolevulinic acid and diamino acid derivatives of protoporphyrin IX reduces papillomas in mice without eliminating transformation into squamous cell carcinoma of the skin

Photodynamic therapy (PDT) is used to treat malignant and nonmalignant diseases. It is also used for cosmetological skin treatment. PDT is generally considered to have a low risk of carcinogenicity. However, instances of nonmalignant human tumors turning malignant have been linked to PDT. In this study, we used 5-aminolevulinic (ALA) acid and 3 water soluble photosensitizers-PP(Arg)(2), PP(Ser)(2)Arg(2), PP(Ala)(2)Arg(2), all diamino acid derivatives of protoporphyrin IX-to treat benign papillomas in FVB/N mice induced by 7,12-dimethylbenz(a)anthracene (DMBA)-12-O-tetradecanoyl-phorbol-13-acetate (TPA). Of these drugs, ALA and PP(Arg)(2) were found the most efficient. PDT reduced the number of papillomas, but with increasing effectiveness of the drugs, the risk of malignant transformation of the papillomas into squamous cell carcinomas increased. The underlying mechanisms are not clear and further investigations are needed.