Mini Reviews in Medicinal Chemistry - Volume 25, Issue 4, 2025

Photodynamic Therapy (PDT) has emerged as a highly efficient and non-invasive cancer treatment, which is crucial considering the significant global mortality rates associated with cancer. The effectiveness of PDT primarily relies on the quality of the photosensitizers employed. When exposed to appropriate light irradiation, these photosensitizers absorb energy and transition to an excited state, eventually transferring energy to nearby molecules and generating Reactive Oxygen Species (ROS), including singlet oxygen [¹O2]. The ability to absorb light in visible and near-infrared wavelengths makes porphyrins and derivatives useful photosensitizers for PDT. Chemically, Porphyrins, composed of tetra-pyrrole structures connected by four methylene groups, represent the typical photosensitizers. The limited water solubility and bio-stability of porphyrin photosensitizers and their non-specific tumor-targeting properties hinder PDT effectiveness and clinical applications. Therefore, a wide range of modification and functionalization techniques have been used to maximize PDT efficiency and develop multidimensional porphyrin-based functional materials. Recent progress in porphyrin-based functional materials has been investigated in this review paper, focusing on two main aspects including the development of porphyrinic amphiphiles that improve water solubility and biocompatibility, and the design of porphyrin-based polymers, including block copolymers with covalent bonds and supramolecular polymers with noncovalent bonds, which provide versatile platforms for PDT applications. The development of porphyrin-based functional materials will allow researchers to significantly expand PDT applications for cancer therapy by opening up new opportunities. With these innovations, porphyrins will overcome their limitations and push PDT to the forefront of cancer treatment options.

Cuproptosis, an emerging concept in the field of diabetes research, presents a novel and promising perspective for the effective management of diabetes mellitus and its associated complications. Diabetes, characterized by chronic hyperglycemia, poses a substantial global health burden, with an increasing prevalence worldwide. Despite significant progress in our understanding of this complex metabolic disorder, optimal therapeutic strategies still remain elusive. The advent of cuproptosis, a term coined to describe copper-induced cellular cell death and its pivotal role in diabetes pathogenesis, opens new avenues for innovative interventions. Copper, an indispensable trace element, plays a pivotal role in a myriad of vital biological processes, encompassing energy production, bolstering antioxidant defenses, and altered cellular signaling. However, in the context of diabetes, this copper homeostasis is perturbed, driven by a combination of genetic predisposition, dietary patterns, and environmental factors. Excessive copper levels act as catalysts for oxidative stress, sparking intricate intracellular signaling cascades that further exacerbate metabolic dysfunction. In this review, we aim to explore the interrelationship between copper and diabetes comprehensively, shedding light on the intricate mechanisms underpinning cuproptosis. By unraveling the roles of copper transporters, copper-dependent enzymes, and cuproptotic signaling pathways, we seek to elucidate potential therapeutic strategies that harness the power of copper modulation in diabetes management. This insight sets the stage for a targeted approach to challenge the complex hurdles posed by diabetes, potentially transforming our therapeutic strategies in the ongoing fight against this pervasive global health concern.

The B-cell lymphoma-2 (Bcl-2) protein family plays a crucial role as a regulator in the process of apoptosis. There is a substantial body of evidence indicating that the upregulation of anti-apoptotic Bcl-2 proteins is prevalent in several cancer cell lines and original tumour tissue samples. This phenomenon plays a crucial role in enabling tumour cells to avoid apoptosis, hence facilitating the development of resistant cells against chemotherapy. Therefore, the success rate of chemotherapy for cancer can be enhanced by the down-regulation of anti-apoptotic Bcl-2 proteins. Furthermore, the indole structural design is commonly found in a variety of natural substances and biologically active compounds, particularly those that possess anti-cancer properties. Due to its distinctive physicochemical and biological characteristics, it has been highly regarded as a fundamental framework in the development and production of anti-cancer drugs. As a result, a considerable range of indole derivatives, encompassing both naturally occurring and developed compounds, have been identified as potential candidates for the treatment of cancer. Several of these derivatives have advanced to clinical trials, while others are already being used in clinical settings. This emphasizes the significant role of indole in the field of research and development of anti-cancer therapeutics. This study provides an overview of apoptosis and the structural characteristics of Bcl-2 family proteins, and mainly examines the present stage and recent developments in Bcl-2 inhibitors with an indole scaffold embedded in their structure.

Analysis of the biochemical differences in the energy metabolism among bi-dimensional (2D) and tri-dimensional (3D) cultured cancer cell models and actual human tumors was undertaken. In 2D cancer cells, the oxidative phosphorylation (OxPhos) fluxes range is 2.5-19 nmol O2/min/mg cellular protein. Hypoxia drastically decreased OxPhos flux by 2-3 times in 2D models, similar to what occurs in mature multicellular tumor spheroids (MCTS), a representative 3D cancer cell model. However, mitochondrial protein contents and enzyme activities were significantly different between both models. Moreover, glycolytic fluxes were also significantly different between 2D and MCTS. The glycolytic flux range in 2D models is 1-34 nmol lactate/min/mg cellular protein, whereas in MCTS the range of glycolysis fluxes is 60-80 nmol lactate/min/mg cellular. In addition, sensitivity to anticancer canonical and metabolic drugs was greater in MCTS than in 2D. Actual solid human tumor samples show lower (1.6-4.5 times) OxPhos fluxes compared to normoxic 2D cancer cell cultures. These observations indicate that tridimensional organization provides a unique microenvironment affecting tumor physiology, which has not been so far faithfully reproduced by the 2D environment. Thus, the analysis of the resemblances and differences among cancer cell models undertaken in the present study raises caution on the interpretation of results derived from 2D cultured cancer cells when they are extended to clinical settings. It also raises awareness about detecting which biological and environmental factors are missing in 2D and 3D cancer cell models to be able to reproduce the actual human tumor behavior.