Delivery of an immunogenic cell death-inducing copper complex to cancer stem cells using polymeric nanoparticles

Metal-based immunogenic cell death inducers for cancer immunotherapy

Immunogenic cell death (ICD) has attracted enormous attention over the past decade due to its unique characteristics in cancer cell death and its role in activating innate and adaptive immune responses against tumours. Many efforts have been dedicated to screening, identifying and discovering ICD inducers, resulting in the validation of several based on metal complexes. In this review, we provide a comprehensive summary of current metal-based ICD inducers, their molecular mechanisms for triggering ICD initiation and subsequent protective antitumour immune responses, along with considerations for validating ICD both in vitro and in vivo. We also aim to offer insights into the future development of metal complexes with enhanced ICD-inducing properties and their applications in potentiating antitumour immunity.

Recent Development on Copper-Sensor and its Biological Applications: A Review

Metal ion recognition is one of the most prospective research topics in the field of chemical sensors due to its wide range of clinical, biological and environmental applications. In this context, hydrazones are well known compounds that exhibit metal sensing and several biological properties due to the presence of N=CH- bond. Some of the biological properties includes anti-cancer, anti-tumor, anti-oxidant, anti-microbial activities. Hydrazones are also used as a ligand to detect metal ion as well as to generate metal complexes that exhibit medicinal properties. Thus, in recent years, many attempts were made to develop novel ligands with enhanced metal sensing and medicinal properties. In this review, some of the recent development on the hydrazones and their copper complexes are covered from the last few years from 2015-2023. These includes significance of copper ions, synthesis, biological properties, mechanism and metal sensing properties of some of the copper complexes were discussed.

Harnessing nanomaterials for copper-induced cell death

Copper (Cu), an essential micronutrient with redox properties, plays a pivotal role in a wide array of pathological and physiological processes across virtually all cell types. Maintaining an optimal copper concentration is critical for cellular survival: insufficient copper levels disrupt respiration and metabolism, while excess copper compromises cell viability, potentially leading to cell death. Similarly, in the context of cancer, copper exhibits a dual role: appropriate amount of copper can promote tumor progression and be an accomplice, yet beyond befitting level, copper can bring about multiple types of cell death, including autophagy, apoptosis, ferroptosis, immunogenic cell death, pyroptosis, and cuproptosis. These forms of cell death are beneficial against cancer progression; however, achieving precise copper regulation within tumors remains a significant challenge in the pursuit of effective cancer therapies. The emergence of nanodrug delivery systems, distinguished by their precise targeting, controlled release, high payload capacity, and the ability to co-deliver multiple agents, has revitalized interest in exploiting copper's precise regulatory capabilities. Nevertheless, there remains a dearth of comprehensive review of copper's bidirectional effects on tumorigenesis and the role of copper-based nanomaterials in modulating tumor progression. This paper aims to address this gap by elucidating the complex role in cancer biology and highlighting its potential as a therapeutic target. Through an exploration of copper's dualistic nature and the application of nanotechnology, this review seeks to offer novel insights and guide future research in advancing cancer treatment.

Copper-instigated modulatory cell mortality mechanisms and progress in oncological treatment investigations

Copper, a transition metal, serves as an essential co-factor in numerous enzymatic active sites and constitutes a vital trace element in the human body, participating in crucial life-sustaining activities such as energy metabolism, antioxidation, coagulation, neurotransmitter synthesis, iron metabolism, and tetramer deposition. Maintaining the equilibrium of copper ions within biological systems is of paramount importance in the prevention of atherosclerosis and associated cardiovascular diseases. Copper induces cellular demise through diverse mechanisms, encompassing reactive oxygen species responses, apoptosis, necrosis, pyroptosis, and mitochondrial dysfunction. Recent research has identified and dubbed a novel regulatory cell death modality-"cuprotosis"-wherein copper ions bind to acylated proteins in the tricarboxylic acid cycle of mitochondrial respiration, resulting in protein aggregation, subsequent downregulation of iron-sulfur cluster protein expression, induction of proteotoxic stress, and eventual cell death. Scholars have synthesized copper complexes by combining copper ions with various ligands, exploring their significance and applications in cancer therapy. This review comprehensively examines the multiple pathways of copper metabolism, copper-induced regulatory cell death, and the current status of copper complexes in cancer treatment.

Comprehensive analysis of cuproptosis-related long noncoding RNA for predicting prognostic and diagnostic value and immune landscape in colorectal adenocarcinoma

BACKGROUND

Cuproptosis, as a copper-induced mitochondrial cell death, has attracted extensive attention recently, especially in cancer. Although some key regulatory genes have been identified in cuproptosis, the related lncRNAs have not been further studied. Exploring the prognostic and diagnostic value of cuproptosis-related lncRNAs (CRLs) in colon adenocarcinoma and providing guidance for individualized immunotherapy for patients are of great significance.

RESULTS

A total of 2003 lncRNAs were correlated with cuproptosis genes and considered as CRLs. We screened 33 survival-associated CRLs and established a prognostic signature base on 7 CRLs in the training group. The patients in the low-risk group had better outcomes in both training group (P < 0.001) and test group (P = 0.016). More exciting, our model showed good prognosis prediction in both stage I-II (P = 0.020) and stage III-IV (P = 0.001). The nomogram model could further improve the accuracy of prognosis prediction. Interestingly, glucose-related metabolic pathways, which were closely related to cuproptosis, were enriched in the low-risk group. Meanwhile, the immune infiltration scores were lower in the high-risk group. The high-risk group was more sensitive to OSI.906 and ABT.888, while low-risk group was more sensitive to Sorafenib. Three lncRNAs, FALEC, AC083967.1 and AC010997.4, were highly expressed in serum of COAD patients, and the AUC was 0.772, 0.726 and 0.714, respectively, indicating their valuable diagnostic value.

CONCLUSIONS

Our research constructed a prognostic signature based on 7 CRLs and found three promising diagnostic markers for COAD patients. Our results provided a reference to the personalized immunotherapy strategies.

Payload Release Profile and Anti-Cancer Stem Cell Properties of Compositionally Different Polymeric Nanoparticles Containing a Copper(II) Complex

Cancer stem cells (CSCs) are linked to tumour relapse and metastasis, the main reason for cancer-related deaths. The application of polymeric nanoparticles as drug delivery systems to target CSCs is relatively unexplored. Here, we report the encapsulation of a CSC-potent copper(II) complex 1 by two compositionally different methoxy poly(ethylene glycol)-b-poly(D,L-lactic-co-glycolic) acid (PEG–PLGA) copolymers. Specifically, we used PEG–PLGA (5000:10,000 Da, 1:1 LA:GA) and PEG–PLGA (5000:10,000 Da, 4:1 LA:GA) polymers to prepare spherical nanoparticle formulations 1:1 NP15 and 4:1 NP15, respectively, both with a 15% feed of 1. The two formulations show distinct biophysical and in vitro properties. For example, (i) 4:1 NP15 displays a slower payload release profile than 1:1 NP15 in physiologically relevant solutions, (ii) 4:1 NP15 exhibits statistically greater potency towards breast CSCs than bulk breast cancer cells grown in monolayers, whereas 1:1 NP15 is equally potent towards breast CSCs and bulk breast cancer cells, and (iii) 4:1 NP15 shows significantly greater potency towards three-dimensionally cultured mammospheres than 1:1 NP15. This study shows that the release profile and anti-breast CSC properties of PEG–PLGA nanoparticle formulations (containing 1) can be perturbed (and possibly controlled) by modifying the proportion of glycolic acid within the PLGA component.

Encapsulation and Delivery of an Osteosarcoma Stem Cell Active Gallium(III)-Diflunisal Complex Using Polymeric Micelles

Here we report the encapsulation of an osteosarcoma stem cell (OSC) potent gallium(III)-diflunisal complex 1 into polymeric nanoparticles, and its delivery into osteosarcoma cells. At the optimum feed (20 %, 1 NP²⁰ ), nanoparticle encapsulation of 1 enhances potency towards bulk osteosarcoma cells and OSCs (cultured in monolayer and three-dimensional systems). Strikingly, the nanoparticle formulation exhibits up to 5645-fold greater potency towards OSCs than frontline anti-osteosarcoma drugs, doxorubicin and cisplatin. The nanoparticle formulation evokes a similar mechanism of action as the payload, which bodes well for future translation. Specifically, the nanoparticle formulation induces nuclear DNA damage, cyclooxygenase-2 downregulation, and caspase-dependent apoptosis. To the best of our knowledge, this is the first study to demonstrate that polymeric nanoparticles can be used to effectively deliver an OSC-active metal complex into osteosarcoma cells.

Recent Advances in Copper-Based Organic Complexes and Nanoparticles for Tumor Theranostics

Treatment of drug-resistant forms of cancer requires consideration of their hallmark features, such as abnormal cell death mechanisms or mutations in drug-responding molecular pathways. Malignant cells differ from their normal counterparts in numerous aspects, including copper metabolism. Intracellular copper levels are elevated in various cancer types, and this phenomenon could be employed for the development of novel oncotherapeutic approaches. Copper maintains the cell oxidation levels, regulates the protein activity and metabolism, and is involved in inflammation. Various copper-based compounds, such as nanoparticles or metal-based organic complexes, show specific activity against cancer cells according to preclinical studies. Herein, we summarize the major principles of copper metabolism in cancer cells and its potential in cancer theranostics.

A novel cuproptosis-related molecular pattern and its tumor microenvironment characterization in colorectal cancer

Cuproptosis, or copper-induced cell death, has been reported as a novel noncanonical form of cell death in recent times. However, the potential roles of cuproptosis in the alteration of tumor clinicopathological features and the formation of a tumor microenvironment (TME) remain unclear. In this study, we comprehensively analyzed the cuproptosis-related molecular patterns of 1,274 colorectal cancer samples based on 16 cuproptosis regulators. The consensus clustering algorithm was conducted to identify cuproptosis-related molecular patterns and gene signatures. The ssGSEA and ESTIMATE algorithms were used to evaluate the enrichment levels of the infiltrated immune cells and tumor immune scores, respectively. The cuproptosis score was established to assess the cuproptosis patterns of individuals with principal component analysis algorithms based on the expression of cuproptosis-related genes. Three distinct cuproptosis patterns were confirmed and demonstrated to be associated with distinguishable biological processes and clinical prognosis. Interestingly, the three cuproptosis patterns were revealed to be consistent with three immune infiltration characterizations: immune-desert, immune-inflamed, and immune-excluded. Enhanced survival, activation of immune cells, and high tumor purity were presented in patients with low cuproptosisScore, implicating the immune-inflamed phenotype. In addition, low scores were linked to high tumor mutation burden, MSI-H and high CTLA4 expression, showing a higher immune cell proportion score (IPS). Taken together, our study revealed a novel cuproptosis-related molecular pattern associated with the TME phenotype. The formation of cuproptosisScore will further strengthen our understanding of the TME feature and instruct a more personalized immunotherapy schedule in colorectal cancer.

A novel immunochemotherapy based on immunogenicity-activated and immunosuppression-reversed biomimetic nanoparticles

Studies show that infiltrated myeloid-derived suppressor cells (MDSCs) are vital in the immunosuppressive tumor microenvironment and account for lymphoma refractoriness and recurrence. Here, we developed a biomimetic nanoplatform (PM-PLGA-DOX/GEM) in which platelet membranes (PM) wrap PLGA nanoparticles co-loaded with doxorubicin (DOX) and gemcitabine (GEM). PM-PLGA-DOX/GEM would accumulate in tumor tissues because of the enhanced permeation and retention (EPR) effect and the tumor cell-induced platelet aggregation (TCIPA) effect. GEM could eliminate the MDSCs in tumor tissues, thereby reversing the immunosuppressive tumor microenvironment. Furthermore, DOX could invoke the immunogenic cell death (ICD) of lymphoma cells. Consequently, numerous T cells were recruited and activated to improve the therapeutic effects. This study will offer a potential platform for clinical treatment of lymphoma and other solid tumors.