Angewandte Chemie International Edition

Theranostic Layer‐by‐Layer Nanoparticles for Simultaneous Tumor Detection and Gene Silencing

AbstractLayer‐by‐layer nanoparticles (NPs) are modular drug delivery vehicles that incorporate multiple functional materials through sequential deposition of polyelectrolytes onto charged nanoparticle cores. Herein, we combined the multicomponent features and tumor targeting capabilities of layer‐by‐layer assembly with functional biosensing peptides to create a new class of nanotheranostics. These NPs encapsulate a high weight percentage of siRNA while also carrying a synthetic biosensing peptide on the surface that is cleaved into a urinary reporter upon exposure to specific proteases overexpressed in the tumor microenvironment. Importantly, this biosensor reports back on a molecular signature characteristic to metastatic tumors and associated with poor prognosis, MMP9 protease overexpression. This nanotheranostic mediates noninvasive urinary‐based diagnostics in mouse models of three different cancers with simultaneous gene silencing in flank and metastatic mouse models of ovarian cancer.

An Anticancer Rhenium Tricarbonyl Targets Fe−S Cluster Biogenesis in Ovarian Cancer Cells

AbstractTarget identification remains a critical challenge in inorganic drug discovery to deconvolute potential polypharmacology. Herein, we describe an improved approach to prioritize candidate protein targets based on a combination of dose‐dependent chemoproteomics and treatment effects in living cancer cells for the rhenium tricarbonyl compound TRIP. Chemoproteomics revealed 89 distinct dose‐dependent targets with concentrations of competitive saturation between 0.1 and 32 μM despite the broad proteotoxic effects of TRIP. Target‐response networks revealed two highly probable targets of which the Fe−S cluster biogenesis factor NUBP2 was competitively saturated by free TRIP at nanomolar concentrations. Importantly, TRIP treatment led to a down‐regulation of Fe−S cluster containing proteins and upregulated ferritin. Fe−S cluster depletion was further verified by assessing mitochondrial bioenergetics. Consequently, TRIP emerges as a first‐in‐class modulator of the scaffold protein NUBP2, which disturbs Fe−S cluster biogenesis at sub‐cytotoxic concentrations in ovarian cancer cells.

Fast and Durable Intraoperative Near‐infrared Imaging of Ovarian Cancer Using Ultrabright Squaraine Fluorophores

AbstractThe residual tumor after surgery is the most significant prognostic factor of patients with epithelial ovarian cancer. Near‐infrared (NIR) fluorescence‐guided surgery is actively utilized for tumor localization and complete resection during surgery. However, currently available contrast‐enhancing agents display low on‐target binding, unfavorable pharmacokinetics, and toxicity, thus not ideal for clinical use. Here we report ultrabright and stable squaraine fluorophores with optimal pharmacokinetics by introducing an asymmetric molecular conformation and surface charges for rapid transporter‐mediated cellular uptake. Among the tested, OCTL14 shows low serum binding and rapid distribution into cancer tissue via organic cation transporters (OCTs). Additionally, the charged squaraine fluorophores are retained in lysosomes, providing durable intraoperative imaging in a preclinical murine model of ovarian cancer up to 24 h post‐injection. OCTL14 represents a significant departure from the current bioconjugation approach of using a non‐targeted fluorophore and would provide surgeons with an indispensable tool to achieve optimal resection.

Exosome‐Mimetic Supramolecular Vesicles with Reversible and Controllable Fusion and Fission**

Abstract The fusion and fission behaviors of exosomes are essential for the cell‐to‐cell communication. Developing exosome‐mimetic vesicles with such behaviors is of vital importance, but still remains a big challenge. Presented herein is an artificial supramolecular vesicle that exhibits redox‐modulated reversible fusion‐fission functions. These vesicles tend to fuse together and form large‐sized vesicles upon oxidation, undergo a fission process and then return to small‐sized vesicles through reduction. Noteworthy, the aggregation‐induced emission (AIE) characteristics of the supramolecular building blocks enable the molecular configuration during vesicular transformation to be monitored by fluorescence technology. Moreover, the presented vesicles are excellent nanocarrier candidates to transfer siRNA into cancer cells.

A Smart Theranostic Prodrug System Activated by Reactive Oxygen Species for Regional Chemotherapy of Metastatic Cancer

AbstractMetastatic cancer is difficult to cure because of its uncontrollable nature and side effects during treatment. We constructed a reactive oxygen species (ROS)‐activated smart theranostic prodrug system based on an ROS active site linked with both a targeting group and an anticancer drug for efficient regional chemotherapy of metastatic cancers. The optimized prodrug (Bio‐(8)‐MB‐CPT) with biotin as the targeting group displayed high sensitivity towards ROS and selectively targeting ability towards cervical cancer cells, showing highly efficient drug release (up to 92 %) in vitro. Bio‐(8)‐MB‐CPT thus exerted strong toxicity towards cervical cancer cells, but unlike the parent drug (camptothecin), showed no toxicity towards normal cells. Moreover, the prodrug displayed significantly enhanced antitumor efficacy in vivo and eradicated the tumor with no obvious side effects (inhibition of the tumor reached up to 99.9 %).

Unlocking the Power of Human Ferritin: Enhanced Drug Delivery of Aurothiomalate in A2780 Ovarian Cancer Cells

AbstractAurothiomalate (AuTM) is an FDA‐approved antiarthritic gold drug with unique anticancer properties. To enhance its anticancer activity, we prepared a bioconjugate with human apoferritin (HuHf) by attaching some AuTM moieties to surface protein residues. The reaction of apoferritin with excess AuTM yielded a single adduct, that was characterized by ESI MS and ICP‐OES analysis, using three mutant ferritins and trypsinization experiments. The adduct contains ~3 gold atoms per ferritin subunit, arranged in a small cluster bound to Cys90 and Cys102. MD simulations provided a plausible structural model for the cluster. The adduct was evaluated for its pharmacological properties and was found to be significantly more cytotoxic than free AuTM against A2780 cancer cells mainly due to higher gold uptake. NMR‐metabolomics showed that AuTM bound to HuHf and free AuTM induced qualitatively similar changes in treated cancer cells, indicating that the effects on cell metabolism are approximately the same, in agreement with independent biochemical experiments. In conclusion, we have demonstrated here that a molecularly precise bioconjugate formed between AuTM and HuHf exhibits anticancer properties far superior to the free drug, while retaining its key mechanistic features. Evidence is provided that human ferritin can serve as an excellent carrier for this metallodrug.

An Aptamer‐Based Nanoflow Cytometry Method for the Molecular Detection and Classification of Ovarian Cancers through Profiling of Tumor Markers on Small Extracellular Vesicles

AbstractMolecular profiling of protein markers on small extracellular vesicles (sEVs) is a promising strategy for the precise detection and classification of ovarian cancers. However, this strategy is challenging owing to the lack of simple and practical detection methods. In this work, using an aptamer‐based nanoflow cytometry (nFCM) detection strategy, a simple and rapid method for the molecular profiling of multiple protein markers on sEVs was developed. The protein markers can be easily labeled with aptamer probes and then rapidly profiled by nFCM. Seven cancer‐associated protein markers, including CA125, STIP1, CD24, EpCAM, EGFR, MUC1, and HER2, on plasma sEVs were profiled for the molecular detection and classification of ovarian cancers. Profiling these seven protein markers enabled the precise detection of ovarian cancer with a high accuracy of 94.2 %. In addition, combined with machine learning algorithms, such as linear discriminant analysis (LDA) and random forest (RF), the molecular classifications of ovarian cancer cell lines and subtypes were achieved with overall accuracies of 82.9 % and 55.4 %, respectively. Therefore, this simple, rapid, and non‐invasive method exhibited considerable potential for the auxiliary diagnosis and molecular classification of ovarian cancers in clinical practice.

A Triple Threat Against Ovarian Cancer: Os(II)‐Pt(IV)‐Ceritinib Conjugates for Photodynamic Therapy, Chemotherapy, and Immunogenic Cell Death Induction

Abstract Metal‐based anticancer agents offer unique opportunities to integrate multiple therapeutic modalities within a single molecular framework. Herein, we present the first Osmium(II)‐Platinum(IV)‐Ceritinib conjugate ( Os‐Pt‐Cer ) that synergistically combines photodynamic therapy (PDT), chemotherapy, and immunotherapy via immunogenic cell death (ICD) induction. This heterobimetallic complex features a photoactive osmium(II) polypyridyl core, a platinum(IV) prodrug derived from oxaliplatin, and the kinase inhibitor ceritinib as an axial ligand. Upon deep‐red irradiation ( λ = 740 nm), the conjugate exhibits potent antiproliferative activity in ovarian 2D cancer cells and 3D tumour spheroids, with IC 50 values in the low nanomolar range. In addition, Os‐Pt‐Cer effectively inhibits cancer cell migration. Mechanistic studies reveal that the conjugate induces hallmarks of ICD, including calreticulin exposure, ATP release, HMGB1 secretion and phagocytosis. This multifunctional approach highlights the potential of osmium(II)‐platinum(IV) conjugates as promising candidates for overcoming resistance and immune evasion in high‐grade ovarian carcinoma.

Exploring Ovarian Cancer Cell Resistance to Rhenium Anticancer Complexes

AbstractRhenium tricarbonyl complexes have been recently investigated as novel anticancer agents. However, little is understood about their mechanisms of action, as well as the means by which cancer cells respond to chronic exposure to these compounds. To gain a deeper mechanistic insight into these rhenium anticancer agents, we developed and characterized an ovarian cancer cell line that is resistant to a previously studied compound [Re(CO)3(dmphen)(ptolICN)]+, where dmphen=2,9‐dimethyl‐1,10‐phenanthroline and ptolICN=para‐tolyl isonitrile, called TRIP. This TRIP‐resistant ovarian cancer cell line, A2780TR, was found to be 9 times less sensitive to TRIP compared to the wild‐type A2780 ovarian cancer cell line. Furthermore, the cytotoxicities of established drugs and other rhenium anticancer agents in the TRIP‐resistant cell line were determined. Notably, the drug taxol was found to exhibit a 184‐fold decrease in activity in the A2780TR cell line, suggesting that mechanisms of resistance towards TRIP and this drug are similar. Accordingly, expression levels of the ATP‐binding cassette transporter P‐glycoprotein, an efflux transporter known to detoxify taxol, were found to be elevated in the A2780TR cell line. Additionally, a gene expression analysis using the National Cancer Institute 60 cell line panel identified the MT1E gene to be overexpressed in cells that are less sensitive to TRIP. Because this gene encodes for metallothioneins, this result suggests that detoxification by this class of proteins is another mechanism for resistance to TRIP. The importance of this gene in the A2780TR cell line was assessed, confirming that its expression is elevated in this cell line as well. As the first study to investigate and identify the cancer cell resistance pathways in response to a rhenium complex, this report highlights important similarities and differences in the resistance responses of ovarian cancer cells to TRIP and conventional drugs.

Development of CDK2 and CDK5 Dual Degrader TMX‐2172

AbstractCyclin‐dependent kinase 2 (CDK2) is a potential therapeutic target for the treatment of cancer. Development of CDK2 inhibitors has been extremely challenging as its ATP‐binding site shares high similarity with CDK1, a related kinase whose inhibition causes toxic effects. Here, we report the development of TMX‐2172, a heterobifunctional CDK2 degrader with degradation selectivity for CDK2 and CDK5 over not only CDK1, but transcriptional CDKs (CDK7 and CDK9) and cell cycle CDKs (CDK4 and CDK6) as well. In addition, we demonstrate that antiproliferative activity in ovarian cancer cells (OVCAR8) depends on CDK2 degradation and correlates with high expression of cyclin E1 (CCNE1), which functions as a regulatory subunit of CDK2. Collectively, our work provides evidence that TMX‐2172 represents a lead for further development and that CDK2 degradation is a potentially valuable therapeutic strategy in ovarian and other cancers that overexpress CCNE1.