Dual Action of Acidic Microenvironment on the Enrichment of the Active Metabolite of Disulfiram in Tumor Tissues

Copper Deposition in Polydopamine Nanostructure to Promote Cuproptosis by Catalytically Inhibiting Copper Exporters of Tumor Cells for Cancer Immunotherapy

Cuproptosis is an emerging programmed cell death, displaying great potential in cancer treatment. However, intracellular copper content to induce cuproptosis is unmet, which mainly ascribes to the intracellular pumping out equilibrium mechanism by copper exporter ATP7A and ATP7B. Therefore, it is necessary to break such export balance mechanisms for desired cuproptosis. Mediated by diethyldithiocarbamate (DTC) coordination, herein a strategy to efficiently assemble copper ions into polydopamine nanostructure (PDA-DTC/Cu) for reprogramming copper metabolism of tumor is developed. The deposited Cu2+ can effectively trigger the aggregation of lipoylated proteins to induce cuproptosis of tumor cells. Beyond elevating intracellular copper accumulation, PDA-DTC/Cu enables to break the balance of copper metabolism by disrupting mitochondrial function and restricting the adenosine triphosphate (ATP) energy supply, thus catalytically inhibiting the expressions of ATP7A and ATP7B of tumor cells to enhance cuproptosis. Meanwhile, the killed tumor cells can induce immunogenic cell death (ICD) to stimulate the immune response. Besides, PDA-DTC/Cu NPs can promote the repolarization of tumor-associated macrophages (TAMs ) to relieve the tumor immunosuppressive microenvironment (TIME). Collectively, PDA-DTC/Cu presented a promising "one stone two birds" strategy to realize copper accumulation and inhibit copper export simultaneously to enhance cuproptosis for 4T1 murine breast cancer immunotherapy.

Identification of a Novel Cuproptosis-Related Gene Signature and Integrative Analyses in Thyroid Cancer

Cuproptosis is a novel programmed cell death that depends on copper. The role and potential mechanism of cuproptosis-related genes (CRGs) in thyroid cancer (THCA) are still unclear. In our study, we randomly divided THCA patients from the TCGA database into a training set and a testing set. A cuproptosis-related signature consisting of six genes (SLC31A1, LIAS, DLD, MTF1, CDKN2A, and GCSH) was constructed using the training set to predict the prognosis of THCA and was verified with the testing set. All patients were classified into low- and high-risk groups according to risk score. Patients in the high-risk group had a poorer overall survival (OS) than those in the low-risk group. The area under the curve (AUC) values for 5 years, 8 years, and 10 years were 0.845, 0.885, and 0.898, respectively. The tumor immune cell infiltration and immune status were significantly higher in the low-risk group, which indicated a better response to immune checkpoint inhibitors (ICIs). The expression of six cuproptosis-related genes in our prognostic signature were verified by qRT-PCR in our THCA tissues, and the results were consistent with TCGA database. In summary, our cuproptosis-related risk signature has a good predictive ability regarding the prognosis of THCA patients. Targeting cuproptosis may be a better alternative for THCA patients.

αvβ3 integrin-specific exosomes engineered with cyclopeptide for targeted delivery of triptolide against malignant melanoma

Background

Melanoma is the most malignant skin tumor and is difficult to cure with the alternative treatments of chemotherapy, biotherapy, and immunotherapy. Our previous study showed that triptolide (TP) exhibited powerful tumoricidal activity against melanoma. However, the clinical potential of TP is plagued by its poor aqueous solubility, short half-life, and biotoxicity. Therefore, developing an ideal vehicle to efficiently load TP and achieving targeted delivery to melanoma is a prospective approach for making full use of its antitumor efficacy.

Results

We applied exosome (Exo) derived from human umbilical cord mesenchymal stromal cells (hUCMSCs) and engineered them exogenously with a cyclic peptide, arginine-glycine-aspartate (cRGD), to encapsulate TP to establish a bionic-targeted drug delivery system (cRGD-Exo/TP), achieving synergism and toxicity reduction. The average size of cRGD-Exo/TP was 157.34 ± 6.21 nm, with a high drug loading of 10.76 ± 1.21%. The in vitro antitumor results showed that the designed Exo delivery platform could be effectively taken up by targeted cells and performed significantly in antiproliferation, anti-invasion, and proapoptotic activities in A375 cells via the caspase cascade and mitochondrial pathways and cell cycle alteration. Furthermore, the biodistribution and pharmacokinetics results demonstrated that cRGD-Exo/TP possessed superior tumor targetability and prolonged the half-life of TP. Notably, cRGD-Exo/TP significantly inhibited tumor growth and extended survival time with negligible systemic toxicity in tumor-bearing mice.

Conclusion

The results indicated that the functionalized Exo platform provides a promising strategy for targeted therapy of malignant melanoma.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01597-1.

High expression of cuproptosis-related SLC31A1 gene in relation to unfavorable outcome and deregulated immune cell infiltration in breast cancer: an analysis based on public databases

Cuproptosis induction represents a promising alternative for immunotherapies and targeted therapies in breast cancer. This study aimed to investigate the prognostic and biological significance of cuproptosis-related genes in breast cancer. In the current study, we examined the transcriptional and clinical data of 13 cuproptosis-related genes in patients with breast cancer from TCGA database. We found that genes DLAT, SLC31A1, ATP7A and ATP7B were significantly related to the overall survival (OS) of breast cancer patients in univariate Cox regression analysis. Unlike lung or kidney cancers, SLC31A1 expression was upregulated in breast cancer samples compared with normal tissues, and predicted poor prognosis. Univariate and multivariate Cox regression analyses indicated that high SLC31A1 level was an independent prognostic factor for shorter OS. A nomogram integrating SLC31A1, age, T-, N-stage and clinical stage was constructed, and the calibration curves of the 1-, 3-, 5-, 10-year OS fitted well with the ideal model. Furthermore, we found that high SLC31A1 expression was related to deregulated immune response and metabolic pathways. Low SLC31A1 level predicted sensitivity to CTLA4 inhibitors but poor response to paclitaxel. Our study may provide novel insights for copper homeostasis and cuproptosis in breast cancer.

Leveraging disulfiram to treat cancer: Mechanisms of action, delivery strategies, and treatment regimens

Disulfiram (DSF) has been used as an alcoholism drug for 70 years. Recently, it has attracted increasing attention owing to the distinguished anticancer activity, which can be further potentiated by the supplementation of Cu²⁺. Although encouraging anticancer results are obtained in lab, the clinical outcomes of oral DSF are not satisfactory, which urges an in-depth understanding of the underlying mechanisms, bottlenecks, and proposal of potential methods to address the dilemma. In this review, a critical summarization of various molecular biological anticancer mechanisms of DSF/Cu²⁺ is provided and the predicament of orally delivering DSF in clinical oncotherapy is explained by the metabolic barriers. We highlight the recent advances in the DSF/Cu²⁺ delivery strategies and the emerging treatment regimens for cancer treatment. Last but not the least, we summarize the clinical trials regarding DSF and make a prospect of DSF/Cu-based cancer therapy.

Repurposing Disulfiram for Targeting of Glioblastoma Stem Cells: An In Vitro Study

Mesenchymal glioblastoma stem cells (GSCs), a subpopulation in glioblastoma that are responsible for therapy resistance and tumor spreading in the brain, reportedly upregulate aldehyde dehydrogenase isoform-1A3 (ALDH1A3) which can be inhibited by disulfiram (DSF), an FDA-approved drug formerly prescribed in alcohol use disorder. Reportedly, DSF in combination with Cu²⁺ ions exerts multiple tumoricidal, chemo- and radio-therapy-sensitizing effects in several tumor entities. The present study aimed to quantify these DSF effects in glioblastoma stem cells in vitro, regarding dependence on ALDH1A3 expression. To this end, two patient-derived GSC cultures with differing ALDH1A3 expression were pretreated (in the presence of CuSO₄, 100 nM) with DSF (0 or 100 nM) and the DNA-alkylating agent temozolomide (0 or 30 µM) and then cells were irradiated with a single dose of 0–8 Gy. As read-outs, cell cycle distribution and clonogenic survival were determined by flow cytometry and limited dilution assay, respectively. As a result, DSF modulated cell cycle distribution in both GSC cultures and dramatically decreased clonogenic survival independently of ALDH1A3 expression. This effect was additive to the impairment of clonogenic survival by radiation, but not associated with radiosensitization. Of note, cotreatment with temozolomide blunted the DSF inhibition of clonogenic survival. In conclusion, DSF targets GSCs independent of ALDH1A3 expression, suggesting a therapeutic efficacy also in glioblastomas with low mesenchymal GSC populations. As temozolomide somehow antagonized the DSF effects, strategies for future combination of DSF with the adjuvant standard therapy (fractionated radiotherapy and concomitant temozolomide chemotherapy followed by temozolomide maintenance therapy) are not supported by the present study.