Cisplatin binds to the MDM2 RING finger domain and inhibits the ubiquitination activity

Reactions of Cisplatin with Thioredoxin-1 Regulate Intracellular Redox Homeostasis

Cisplatin is a widely used anticancer drug. In addition to inducing DNA damage, increased levels of reactive oxygen species (ROS) play a significant role in cisplatin-induced cell death. Thioredoxin-1 (Trx1), a redox regulatory protein that can scavenge ROS, has been found to eliminate cisplatin-induced ROS, while elevated Trx1 levels are associated with cisplatin resistance. However, it is unknown whether the effect of Trx1 on the cellular response to cisplatin is due to its direct reaction and how this reaction influences the activity of Trx1. In this work, we performed detailed studies of the reaction between Trx1 and cisplatin. Trx1 is highly reactive to cisplatin, and the catalytic motif of Trx1 (CGPC) is the primary binding site of cisplatin. Trx1 can bind up to 6 platinum moieties, resulting in the structural alteration and oligomerization of Trx1 depending on the degree of platination. Platination of Trx1 inhibits its interaction with ASK1, a Trx1-binding protein that regulates cell apoptosis. Furthermore, the reaction with cisplatin suppresses drug-induced ROS generation, which could be associated with drug resistance. This study provides more insight into the mechanism of action of cisplatin.

p53 dry gene powder enhances anti-cancer effects of chemotherapy against malignant pleural mesothelioma

Dry gene powder is a novel non-viral gene-delivery system, which is inhalable with high gene expression. Previously, we showed that the transfection of p16INK4a or TP53 by dry gene powder resulted in growth inhibitions of lung cancer and malignant pleural mesothelioma (MPM) in vitro and in vivo. Here, we report that dry gene powder containing p53- expression-plasmid DNA enhanced the therapeutic effects of cisplatin (CDDP) against MPM even in the presence of endogenous p53. Furthermore, our results indicated that the safe transfection with a higher plasmid DNA (pDNA) concentration suppressed MPM growth independently of chemotherapeutic agents. To develop a new therapeutic alternative for MPM patients without safety concerns over "vector doses", our in vitro data provide basic understandings for dry gene powder.

Cancer therapeutic strategies based on metal ions

As a necessary substance to maintain the body's normal life activities, metal ions are ubiquitous in organisms and play a major role in various complex physiological and biochemical processes, such as material transportation, energy conversion, information transmission, metabolic regulation, etc. Their abnormal distribution/accumulation in cells can interfere with these processes, causing irreversible physical damage to cells or activating biochemical reactions to induce cell death. Therefore, metal ions can be exploited against a wide spectrum of cancers with high efficiency and without drug resistance, which can effectively inhibit the growth of cancer cells by triggering biocatalysis, breaking the osmotic balance, affecting metabolism, interfering with signal transduction, damaging DNA, etc. This perspective systematically summarizes the latest research progress of metal ion-based anti-tumor therapy, and emphasizes the challenges and development directions of this type of therapeutic strategy, hoping to provide a general implication for future research.