Anticancer Activities of Re(I) Tricarbonyl and Its Imidazole-Based Ligands: Insight from a Theoretical Approach

Synthesis, Molecular Docking, and Anticancer Screening of Ester-Based Thiazole Derivatives

This study investigates the potential of five compounds as novel anticancer agents. We examined their efficacy, mechanisms of action, and impact on various cancer cell lines, through a comprehensive set of experiments. Notably, compound 3e demonstrated superior activity compared to the positive control cisplatin, with a GI50 value of 6.3±0.7 μM against the breast cancer cell line (MCF-7). Compound 3b also displayed remarkable growth inhibition, yielding GI50 values of 8.7±0.2 μM (MCF-7) and 8.9±0.5 μM against the colon cancer cell line (HCT-116). Cell count experiments further confirmed the potent inhibitory effects of compounds 3e, 3b, and 3c on MCF-7 and HCT-116 cell growth. Compound 3e demonstrated a reduction of 55-60 % at GI50 and complete inhibition (100 %) at 2x GI50. Compound 3b exhibited 50-55 % reduction (GI50) and 90-95 % inhibition (2x GI50) in HCT-116 cells. Compound 3c displayed 75-80 % inhibition (2x GI50) and 35-40 % inhibition (GI50) in HCT-116 cells. In-depth mechanistic investigations unveiled valuable insights into the mode of action of compound 3e. The cell-cycle assay demonstrated G2/M phase arrest, DNA damage, and caspase-mediated apoptosis in both MCF-7 and HCT-116 cells. Caspase activation indicated a significant increase in apoptosis following exposure to compound 3e. Furthermore, compound 3e induced reactive oxygen species (ROS) production, influencing HCT-116 and MCF-7 cells differently. Elevated ROS production in HCT-116 cells and distinct effects in MCF-7 cells contribute to a deeper understanding of the cytotoxic mechanisms of compound 3e. Overall, these findings highlight the potential of the investigated compounds, particularly compound 3e, as effective inducers of apoptosis in cancer cells. Mechanistic insights into cell cycle arrest, caspase-mediated apoptosis, and ROS modulation provide a comprehensive understanding of their cytotoxic effects. This study offers significant contribution to the development of promising anticancer agents and their therapeutic applications.

Visible and Red Light-Triggered Anticancer Profile of a Ferrocene-Re(I)-Tricarbonyl Conjugate: Experimental and Theoretical Studies

We have red-shifted the light absorbance property of a Re(I)-tricarbonyl complex via distant conjugation of a ferrocene moiety and developed a novel complex ReFctp, [Re(Fctp)(CO)3Cl], where Fctp = 4'-ferrocenyl-2,2':6',2″-terpyridine. ReFctp showed green to red light absorption ability and blue emission, indicating its potential for photodynamic therapy (PDT) application. The conjugation of ferrocene introduced ferrocene-based transitions, which lie at a higher wavelength within the PDT therapeutic window. The time-dependent density functional theory and excited state calculations revealed an efficient intersystem crossing for ReFctp, which is helpful for PDT. ReFctp elicited both PDT type I and type II pathways for reactive oxygen species (ROS) generation and facilitated NADH (1,4-dihydro-nicotinamide adenine dinucleotide) oxidation upon exposure to visible light. Importantly, ReFctp showed effective penetration through the layers of clinically relevant 3D multicellular tumor spheroids and localized primarily in mitochondria (Pearson's correlation coefficient, PCC = 0.65) of A549 cancer cells. ReFctp produced more than 20 times higher phototoxicity (IC50 ∼1.5 μM) by inducing ROS generation and altering mitochondrial membrane potential in A549 cancer cells than the nonferrocene analogue Retp, [Re(CO)3(tp)Cl], where tp = 2,2':6',2″-terpyridine. ReFctp induced apoptotic mode of cell death with a notable photocytotoxicity index (PI, PI = IC50dark/IC50light) and selectivity index (SI, SI = normal cell's IC50dark/cancer cell's IC50light) in the range of 25-33.

Recent drug design strategies and identification of key heterocyclic scaffolds for promising anticancer targets

Cancer, a noncommunicable disease, is the leading cause of mortality worldwide and is anticipated to rise by 75% in the next two decades, reaching approximately 25 million cases. Traditional cancer treatments, such as radiotherapy and surgery, have shown limited success in reducing cancer incidence. As a result, the focus of cancer chemotherapy has switched to the development of novel small molecule antitumor agents as an alternate strategy for combating and managing cancer rates. Heterocyclic compounds are such agents that bind to specific residues in target proteins, inhibiting their function and potentially providing cancer treatment. This review focuses on privileged heterocyclic pharmacophores with potent activity against carbonic anhydrases and kinases, which are important anticancer targets. Evaluation of ongoing pre-clinical and clinical research of heterocyclic compounds with potential therapeutic value against a variety of malignancies as well as the provision of a concise summary of the role of heterocyclic scaffolds in various chemotherapy protocols have also been discussed. The main objective of the article is to highlight key heterocyclic scaffolds involved in recent anticancer drug design that demands further attention from the drug development community to find more effective and safer targeted small-molecule anticancer agents.