Converting an Almost Noncytotoxic Ru(II) Complex with Photolabile Ligands into a Highly Efficient PACT Agent

Ru(II) complexes with weak ligand fields may undergo light-induced ligand dissociation, and the resulted Ru(II) aqua complexes may bind with biomolecules such as DNA, showing potential as photoactivated chemotherapy (PACT) agents. However, Ru(II) complexes with efficient PACT activity are still rare. Some Ru(II) complexes exhibit efficient photoinduced ligand dissociation but poor cytotoxicity. It is speculated that the low nuclear accumulation levels may account for their low PACT efficacy. In order to confirm this hypothesis, the almost noncytotoxic [Ru(7-OCH₃-dppz)(4-OCH₃-py)₄](PF₆)₂ (Ru1) is loaded on nucleus-targeted C₅N₂ nanoparticles (NPs). Compared with the free Ru1, Ru1–C₅N₂ NPs exhibit significantly increased cellular uptake and nuclear accumulation. Therefore, Ru1–C₅N₂ NPs show efficient PACT activity toward various cancer cell lines (including cisplatin-resistant one) with half maximal inhibitory concentration (IC₅₀) values of 0.18 × 10⁻⁶–0.29 × 10⁻⁶ m and phototoxicity index (IC₅₀^dark/IC₅₀^light) values above 137 under both normoxic and hypoxic conditions. Moreover, Ru1–C₅N₂ NPs also exhibit efficient PACT activity toward cisplatin-resistant 3D multicellular tumor spheroids upon two-photon irradiation (800 nm). The same strategy is also feasible to greatly improve the PACT activity of [Ru(7-OCH₃-dppz)(py)₄]²⁺, which itself only has a medium effect. The results may provide new sights for developing efficient Ru(II) PACT agents.     

The Ultrastructure of Tissue Damage by Amyloid Fibrils

Amyloidosis is a group of diseases that includes Alzheimer’s disease, prion diseases, transthyretin (ATTR) amyloidosis, and immunoglobulin light chain (AL) amyloidosis. The mechanism of organ dysfunction resulting from amyloidosis has been a topic of debate. This review focuses on the ultrastructure of tissue damage resulting from amyloid deposition and therapeutic insights based on the pathophysiology of amyloidosis. Studies of nerve biopsy or cardiac autopsy specimens from patients with ATTR and AL amyloidoses show atrophy of cells near amyloid fibril aggregates. In addition to the stress or toxicity attributable to amyloid fibrils themselves, the toxicity of non-fibrillar states of amyloidogenic proteins, particularly oligomers, may also participate in the mechanisms of tissue damage. The obscuration of the basement and cytoplasmic membranes of cells near amyloid fibrils attributable to an affinity of components constituting these membranes to those of amyloid fibrils may also play an important role in tissue damage. Possible major therapeutic strategies based on pathophysiology of amyloidosis consist of the following: (1) reducing or preventing the production of causative proteins; (2) preventing the causative proteins from participating in the process of amyloid fibril formation; and/or (3) eliminating already-deposited amyloid fibrils. As the development of novel disease-modifying therapies such as short interfering RNA, antisense oligonucleotide, and monoclonal antibodies is remarkable, early diagnosis and appropriate selection of treatment is becoming more and more important for patients with amyloidosis.     

基于核酸物理有机化学原理探讨化学致癌相关问题的分子机制

核酸（DNA,RNA）作为遗传信息的载体是生物体内最重要的生物大分子之一。作为有机分子,其功能必然基于其本身结构和化学性质。从核苷酸与寡聚核苷酸的化学反应性质入手阐述3类主要的与DNA的反应,即与静态DNA反应导致结构变化;与动态过程中的DNA反应导致功能受阻;碱基插入型导致突变。详细分析了各类与DNA作用分子的物理化学机制,并讨论其与化学致癌、癌症化疗、化学诱变等在分子层面的联系。希望对核酸相关的化学、生物学及医学的教学与研究有所帮助。     

Self‐Assemble Polymeric Nanoparticle with GSH Exhaustion for SPECT Imaging–Guided Enhanced Radioisotope Therapy

Exploiting biocompatible nanomaterials for cancer theranostics has attracted great attention in recent years. Herein, a multifunctional self‐assembled nanoparticle based on a biocompatible polymer that contains 3‐(4‐hydroxyphenyl) propionic acid N‐hydroxysuccinimide ester (HOPA) for radiolabeling and piperlongumine (PL) for exhausting endogenous glutathione (GSH) (HOPA‐C18PMH‐PEG/PL) is successfully synthesized. With radionuclide ¹²⁵I labeling, SPECT imaging shows high tumor uptake of HOPA‐C18PMH‐PEG/PL after intravenous injection. The in vitro and in vivo combined radioisotope therapy (RIT) and chemotherapy using ¹³¹I‐labeled HOPA‐C18PMH‐PEG/PL is then carried out, achieving synergistic antitumor effect. This is because the reactive oxygen species (ROS) level in the tumor sites of mice treated with ¹³¹I‐labeled HOPA‐C18PMH‐PEG/PL is increased after the exhaustion of GSH by PL. Additionally, such a strategy (exhausting GSH and increasing ROS) induces no obvious toxicity to normal tissue. Therefore, as‐made polymeric nanoparticles exhibit multifunctional properties for SPECT imaging–guided combined RIT and chemotherapy in one system. This finding will further promote polymeric nanoparticle–based RIT of cancer and is expected to be used for future clinical transformation.     

Fine-Tuned Polymer Nanoassembly for Codelivery of Chemotherapeutic Drug and siRNA

Successful clinical application of siRNA to liver-associated diseases reinvigorates the RNAi therapeutics and delivery vectors, especially for anticancer combination therapy. Fine tuning of copolymer-based assembly configuration is highly important for a desirable synergistic cancer cell-killing effect via the codelivery of chemotherapeutic drug and siRNA. Herein, an amphiphilic triblock copolymer methoxyl poly(ethylene glycol)-block-poly(L-lysine)-block-poly(2-(diisopropyl amino)ethyl methacrylate) (abbreviated as mPEG-PLys-PDPA or PLD) consisting of a hydrophilic diblock mPEG-PLys and a hydrophobic block PDPA is synthesized. Three distinct assemblies (i.e., nanosized micelle, nanosized polymersome, and microparticle) are acquired, along with the increase in PDPA block length. Furthermore, the as-obtained polymersome can efficiently codeliver doxorubicin hydrochloride (DOX) as a hydrophilic chemotherapeutic model and siRNA against ADP-ribosylation factor 6 (siArf6) as an siRNA model into cancer cell via lysosomal pH-triggered payload release. PC-3 prostate cell is synergistically killed by the DOX- and siArf6-coloading polymersome (namely PLD@DOX/siArf6). PLD@DOX/siArf6 may serve as a robust nanomedicine for anticancer therapy.     

Epithelial-to-Mesenchymal Transition Is Not a Major Modulating Factor in the Cytotoxic Response to Natural Products in Cancer Cell Lines

Numerous natural products exhibit antiproliferative activity against cancer cells by modulating various biological pathways. In this study, we investigated the potential use of eight natural compounds (apigenin, curcumin, epigallocatechin gallate, fisetin, forskolin, procyanidin B2, resveratrol, urolithin A) and two repurposed agents (fulvestrant and metformin) as chemotherapy enhancers and mesenchymal-to-epithelial (MET) inducers of cancer cells. Screening of these compounds in various colon, breast, and pancreatic cancer cell lines revealed anti-cancer activity for all compounds, with curcumin being the most effective among these in all cell lines. Although some of the natural products were able to induce MET in some cancer cell lines, the MET induction was not related to increased synergy with either 5-FU, irinotecan, gemcitabine, or gefitinib. When synergy was observed, for example with curcumin and irinotecan, this was unrelated to MET induction, as assessed by changes in E-cadherin and vimentin expression. Our results show that MET induction is compound and cell line specific, and that MET is not necessarily related to enhanced chemosensitivity.     

PEG Modificated Bubble-Like Carbon Spherical-W18O49 Using for In Vitro Chemotherapy-Photothermal Synergistic Reverse Cancer Cells

In this study, a chemotherapy-photothermal synergistic anti-tumor system is constructed. Both W₁₈O₄₉@R-C and PEG-W₁₈O₄₉@R-C synthesized by hydrothermal method show the potential of photothermal therapy (PTT). The structure of reflux-carbon is bubble-like spherical and W₁₈O₄₉@R-C obtained by hydrothermal synthesis will cause bubble collapse due to the formation of crystal W₁₈O₄₉; thus, the particle size decreases sharply. Furthermore, the photothermal stability of PEG-W₁₈O₄₉@R-C is higher than that of W₁₈O₄₉@R-C, and ζ-potential measurement indicates that PEG-W₁₈O₄₉@R-C has excellent dispersion characteristics. The test of drug loading and drug release performance show that PEG-modified W₁₈O₄₉@R-C has superior performance on drug loading amount and release capacity. In the synergistic anti-tumor process, the cancer cell viability after co-incubating with PEG-W₁₈O₄₉@R-C+DOX^.HCl (with 808nm) is only 16.6%. These results indicate that PEG-W₁₈O₄₉@R-C has potential in the treatment of cancer by a combination of PTT and chemotherapy.     

The Interaction of Human Glutathione Transferase GSTA1-1 with Reactive Dyes

Human glutathione transferase A1-1 (hGSTA1-1) contributes to developing resistance to anticancer drugs and, therefore, is promising in terms of drug-design targets for coping with this phenomenon. In the present study, the interaction of anthraquinone and diazo dichlorotriazine dyes (DCTD) with hGSTA1-1 was investigated. The anthraquinone dye Procion blue MX-R (PBMX-R) appeared to interact with higher affinity and was selected for further study. The enzyme was specifically and irreversibly inactivated by PBMX-R, following a biphasic pseudo-first-order saturation kinetics, with approximately 1 mol of inhibitor per mol of the dimeric enzyme being incorporated. Molecular modeling and protein chemistry data suggested that the modified residue is the Cys112, which is located at the entrance of the solvent channel at the subunits interface. The results suggest that negative cooperativity exists upon PBMX-R binding, indicating a structural communication between the two subunits. Kinetic inhibition analysis showed that the dye is a competitive inhibitor towards glutathione (GSH) and mixed-type inhibitor towards 1-chloro-2,4-dinitrobenzene (CDNB). The present study results suggest that PBMX-R is a useful probe suitable for assessing by kinetic means the drugability of the enzyme in future drug-design efforts.     

Multiplex fluorescence imaging-guided programmed delivery of doxorubicin and curcumin from a nanoparticles/hydrogel system for synergistic chemotherapy

Synergistic chemotherapy of doxorubicin and curcumin (CUR) is an important strategy for cancer therapy to compensate for the single drug chemotherapy. Programmed and precise delivery of drugs plays a crucial role for optimizing the mode of administration and revealing the mechanism of synergistic chemotherapy. Herein, multiplex fluorescence imaging-guided programmed delivery of doxorubicin and CUR was achieved by a nanoparticles/hydrogel system for synergistic chemotherapy. CUR-loaded nanoparticles and doxorubicin were co-loaded into hydrogel to construct a synergistic chemotherapy drug delivery system. The hydrogel-nanoparticles combined system can effectively achieve the programmed delivery of hydrophilic drug and hydrophobic drug for the synergistic chemotherapy. They exerted the on-demand spatiotemporal delivery of doxorubicin and CUR. The combined chemotherapy system significantly inhibited the tumor growth compared to single therapy. Moreover, the programmed delivery of doxorubicin and CUR was visualized precisely based on their self-fluorescence instead of extra fluorescent tags at the cellular level and in vivo lever using multiplex fluorescence imaging technology. It afforded an imaging guidance for the controllable synergistic chemotherapy based on programmed delivery.