In Vivo Photodynamic Therapy With a Lipophilic Zinc(II) Phthalocyanine Inhibits Colorectal Cancer and Induces a Th1/CD8 Antitumor Immune Response

Structurally diverse zinc(II) complexes containing tripodal tetradentate phenoxido-amines with promising antiproliferative effects

Structurally diverse zinc(II) complexes with tripodal tetradentate phenolic-amines of variable substituents in the phenol and amine moieties were synthesized and thoroughly characterized. The two dinuclear [Zn2(L1)2](ClO4)2·MeOH (1), [Zn2(L2)2](ClO4)2 (2), and four mononuclear [Zn(L3)(H2O)]·MeOH (3), [Zn(L4)] (4), [Zn(L5)] (5) and [Zn(L6)] (6) complexes revealed distorted octahedral, trigonal-bipyramidal or tetrahedral geometries. The free HL1 and H2L3-6 ligands, and complexes 1-6 were evaluated for in vitro cytotoxicity against human cancer cell lines (A2780, A2780R, PC-3 and 22Rv1) and normal healthy MRC-5 cells. Overall results revealed high-to-moderate cytotoxicity (with the best IC50 values for complex 6 ranging from 2.4 to 4.5 μM), which is however, significantly higher than that of the reference drug cisplatin. The moderately active complexes 1-4 showed considerable selectivity on A2780 cells (IC50 ≈ 16.3-19.5 μM) over MRC-5 ones (with IC50 >50 μM for 1, 2 and 4, and with IC50 >25 μM for 3). The complexes 1, 2, and 6 and the ligand H2L6 were chosen for subsequent deeper biological evaluations. Their time-resolved cellular uptake and other cellular effects in A2780 cells were studied, such as cell cycle profile, intracellular ROS production, induction of apoptosis and activation of caspases 3/7. Complexes 1 and 2 caused significant G0/G1 cell cycle arrest in A2780 cells and antioxidant effects at normal conditions. They showed only limited effects on cellular processes connected with cytotoxicity, i.e. induction of apoptosis, depletion of mitochondrial membrane potential, and autophagy. These findings can be at least partly attributed to the low ability of the complexes to enter the A2780 cells and the depression of metabolic activity of the target cancer cells.

Photodynamic Therapy for Colorectal Cancer: An Update and a Look to the Future

This review provides an update on the current state of photodynamic therapy (PDT) for colorectal cancer (CRC) and explores potential future directions in this field. PDT has emerged as a promising minimally invasive treatment modality that utilizes photosensitizers and specific light wavelengths to induce cell death in targeted tumor tissues. In recent years, significant progress has been made in understanding the underlying mechanisms, optimizing treatment protocols, and improving the efficacy of PDT for CRC. This article highlights key advancements in PDT techniques, including novel photosensitizers, light sources, and delivery methods. Furthermore, it discusses ongoing research efforts and potential future directions, such as combination therapies and nanotechnology-based approaches. By elucidating the current landscape and providing insights into future directions, this review aims to guide researchers and clinicians in harnessing the full potential of PDT for the effective management of CRC.

Synergistic antitumor effect of a penicillin derivative combined with thapsigargin in melanoma cells

PURPOSE

To investigate the effect of TAP7f, a penicillin derivative previously characterized as a potent antitumor agent that promotes ER stress and apoptosis, in combination with thapsigargin, an ER stress inducer, on melanoma cells.

METHODS

The synergistic antiproliferative effect of TAP7f in combination with thapsigargin was studied in vitro in murine B16-F0 melanoma cells, and in human A375 and SB2 melanoma cells. In vivo assays were performed with C57BL/6J mice challenged with B16-F0 cells. Immunofluorescence and Western blot assays were carried out to characterize the induction of ER stress and apoptosis. Necrotic tumor areas and the potential toxicity of the combined therapy were examined by histological analysis of tissue sections after hematoxylin-eosin staining.

RESULTS

In vitro, the combination of TAP7f with thapsigargin synergistically inhibited the proliferation of murine B16-F0, and human A375 and SB2 melanoma cells. When non-inhibitory doses of each drug were simultaneously administered to C57BL/6J mice challenged with B16-F0 cells, a 50% reduction in tumor volumes was obtained in the combined group. An apoptotic response characterized by higher expression levels of Baxenhanced PARP-1 cleavage and the presence of active caspase 3 was observed in tumors from the combined treatment. In addition, higher expression levels of GADD153/CHOP and ATF4 were found in tumors of mice treated with both drugs with respect to each drug used alone, indicating the induction of an ER stress response. No signs of tissue toxicity were observed in histological sections of different organs extracted from mice receiving the combination.

CONCLUSION

The synergistic and effective antitumor action of TAP7f in combination with thapsigargin could be considered as a potential therapeutic strategy for melanoma treatment.

Cancer-Targeted Azo Dye for Two-Photon Photodynamic Therapy in Human Colon Tissue

Inappropriate cancer management can be prevented by simultaneous cancer diagnosis, treatment, and real-time assessment of therapeutic processes. Here, we describe the design of a two-photon (TP) photosensitizer (PS), ACC-B, for high temporal and spatioselective near-infrared cancer therapy. ACC-B consisting of a biotin unit significantly enhanced the cancer sensitivity of the PS. Upon TP irradiation, ACC-B generated reactive oxygen species (ROS) through the type I photodynamic therapy (PDT) process and triggered highly selective cancer ablation. In addition, fluorescence microscopy images revealed that ACC-B-loaded live human colon tissues showed a marked difference in ACC-B uptake between normal and cancer tissues, and this property was used for real-time imaging. Upon 770 nm TP treatment, ACC-B generated ROS efficiently in live colon cancer tissues with high spatial selectivity. During PDT, ACC-B can provide in situ spatioselective visualization of cellular behavior and molecular information for therapeutic assessment in specific regions.

Development of porphyrin and titanium dioxide sonosensitizers for sonodynamic cancer therapy

Sonodynamic therapy for malignant tumours has gained much attention for its deep penetration effect and efficient tumour killing ability. The design, modification, and utilization of sonosensitizers are important aspects of sonodynamic therapy. As an essential factor in this process, highly effective sonosensitizers should be developed to facilitate the clinical applications of sonodynamic therapy. This review takes porphyrin- and titanium dioxide (TiO₂)-based systems as representative organic and inorganic sonosensitizers respectively, and summarizes their characteristics and biological effects as sonodynamic therapy. Upon discovery of novel sonosensitizers, sonodynamic therapy becomes an efficient means of adjuvant therapy for the treatment of malignant tumours.

Zinc Complexes with Nitrogen Donor Ligands as Anticancer Agents

The search for anticancer metal-based drugs alternative to platinum derivatives could not exclude zinc derivatives due to the importance of this metal for the correct functioning of the human body. Zinc, the second most abundant trace element in the human body, is one of the most important micro-elements essential for human physiology. Its ubiquity in thousands of proteins and enzymes is related to its chemical features, in particular its lack of redox activity and its ability to support different coordination geometries and to promote fast ligands exchange. Analogously to other trace elements, the impairment of its homeostasis can lead to various diseases and in some cases can be also related to cancer development. However, in addition to its physiological role, zinc can have beneficial therapeutic and preventive effects on infectious diseases and, compared to other metal-based drugs, Zn(II) complexes generally exert lower toxicity and offer few side effects. Zinc derivatives have been proposed as antitumor agents and, among the great number of zinc coordination complexes which have been described so far, this review focuses on the design, synthesis and biological studies of zinc complexes comprising N-donor ligands and that have been reported within the last five years.

Photodynamic diagnosis and photodynamic therapy of colorectal cancer in vitro and in vivo

This review highlights the various photo diagnostic and treatment methods utilized for CRC, over the last seven years.