Augmenting MEK inhibitor efficacy in BRAF wild-type melanoma: synergistic effects of disulfiram combination therapy

Cuproptosis nanoprodrug-initiated self-promoted cascade reactions for postoperative tumor therapy

Cancer metastasis and recurrence remain a regular cause of postoperative death in patients, implying that extra consolidation treatment strategies are needed. Here, a cuproptosis nanoprodrug, termed as Lipo@CP@DQ NPs, is developed to initiate self-promoted cascade reactions to achieve the combinational effect of cuproptosis, in situ chemotherapy, and oxidative stress amplification for effectively suppressing tumor recurrence and metastasis after postoperative treatment. Lipo@CP@DQ NPs are fabricated by loading copper peroxides (Cu2O2, CP) and hydrogen peroxide (H2O2)-repsonsive prodrug DQ into liposomal nanoparticles. Lipo@CP@DQ NPs rapidly dissociate in the acidic tumor microenvironment to release copper ions, H2O2, and prodrug DQ. Subsequently, the excessive accumulation of Cu ions induces cuproptosis and produces highly cytotoxic hydroxyl radicals (•OH). Meanwhile, the self-supplied H2O2 catalyzes the decomposition of DQ to diethyldithiocarbamate (DTC), which is chelated with self-supplied Cu ions to form the anticancer compound, Cu(DTC)2. The another decomposition product, quinone methide (QM), acts as a glutathione (GSH) scavenger for oxidative stress amplification. The synergistic effect of Lipo@CP@DQ NPs-mediated cuproptosis, in situ chemotherapy, and oxidative stress amplification effectively inhibits the growth and postoperative recurrence of triple-negative breast cancer. This work furnishes a strategy for developing cuproptosis-based nanomedicines for effective antitumor treatment after surgery.

Copper-mediated SEC14L3 promotes cuproptosis to inhibit hepatocellular carcinoma growth via ERK/YY1/FDX1 axis

Cuproptosis, a copper-triggered cell death pathway, holds therapeutic potential for cancers, but its regulatory mechanisms in hepatocellular carcinoma (HCC) remain undefined. Despite SEC14L3's known roles in cellular signaling, its involvement in HCC progression and cuproptosis regulation is unclear. Here, we reveal that SEC14L3 expression is downregulated in HCC cells and tissues and correlates with advanced stages and poor prognosis. Copper-induced cuproptosis inhibits HCC cell viability, and SEC14L3 positively modulates cuproptosis in HCC cells by promoting DLAT lipoylation and its oligomerization. Mechanistically, SEC14L3-mediated cuproptosis suppressed HCC growth via the ERK/YY1/FDX1 axis both in vitro and in vivo. Additionally, copper enhanced the SEC14L3 expression, which in turn regulated ERK/YY1/FDX1 axis. Our findings show that copper-mediated SEC14L3 promotes cuproptosis via ERK/YY1/FDX1 axis, thereby inhibiting HCC growth. These insights provide a mechanistic foundation for targeting cuproptosis, advancing the development of SEC14L3-driven therapeutic strategies for HCC.

Copper in melanoma: At the crossroad of protumorigenic and anticancer roles

Copper is an essential micronutrient that is a cofactor for various enzymes involved in multiple cellular processes. Melanoma patients have high serum copper levels, and elevated copper concentrations are found in melanoma tumors. Copper influences the activity of several melanoma-related proteins involved in cell survival, proliferation, pigmentation, angiogenesis, and metastasis. Targeting these processes with copper chelators has shown efficacy in reducing tumor growth and overcoming drug resistance. In contrast, excessive copper can also have detrimental effects when imported into melanoma cells. Multiple distinct cellular effects of copper overload, including the induction of different types of cell death, have been reported. Cuproptosis, a novel type of copper-dependent cell death, has been recently described and is associated with the metabolic phenotype. Melanoma cells can switch between glycolysis and oxidative phosphorylation, which are crucial for tumor growth and drug resistance. In this respect, metabolic plasticity might be exploited for the use of copper-delivery strategies, including repurposing of disulfiram, which is approved for the treatment of noncancer patients. In addition, the development of nanomedicines can improve the targeted delivery of copper to melanoma cells and enable the use of these drugs alone or in combination as copper has been shown to complement targeted therapy and immunotherapy in melanoma cells. However, further research is needed to explore the specific mechanisms of both copper restriction and excess copper-induced processes and determine effective biomarkers for predicting treatment sensitivity in melanoma patients. In this review, we discuss the dual role of copper in melanoma biology.

GSDMD-mediated mitochondrial dysfunction in marginal cells: A potential driver of inflammation and stria vascularis damage in CIHL

Inflammation is among the known causes of cisplatin-induced hearing loss (CIHL), but its exact pathophysiological mechanisms remain unclear. Herein, we demonstrated that pyroptosis-a recently identified inflammatory type of regulated cell death dependent on gasdermin D (GSDMD)-was activated in the cochleae of cisplatin-treated mice, causing CIHL. Meanwhile, treatment with the GSDMD inhibitor necrosulfonamide alleviated CIHL in these mice. To further examine the role of GSDMD-mediated pyroptosis in CIHL, we conducted experiments in Gsdmd-deficient mice. Gsdmd-/- mice demonstrated significantly lower cisplatin-induced cochlear damage than control mice and appeared to be invulnerable to CIHL. Furthermore, GSDMD-mediated pyroptosis in the stria vascularis (SV), but not in the hair cells (HCs), played a dominant role in CIHL. In marginal cells (MCs) of SV, cisplatin induced caspase-dependent GSDMD cleavage, and the pore-forming N-terminal of GSDMD rapidly localized to the mitochondria, leading to abnormal mitochondrial aggregation and oxidative stress. The consequent mitochondrial dysfunction in MCs might result in the severe progression of inflammation, SV damage, and HC loss. Notably, the pharmacological inhibition of pyroptosis using the FDA-approved drug disulfiram effectively alleviated the symptoms of CIHL. Collectively, these findings offer a broad avenue for inhibiting pyroptosis-induced cisplatin ototoxicity and provide valuable theoretical insights for the clinical management of CIHL.

EGFR influences the resistance to targeted therapy in BRAF V600E melanomas by regulating the ferroptosis process

To identify genes differentially expressed between resistant and sensitive BRAF V600E melanoma cell lines using bioinformatics tools applied to GEO data. We retrieved and downloaded the target gene set (GSE45558) from the GEO database and used R software to filter differentially expressed genes (DEGs) between BRAF V600E melanoma cell lines resistant. The identified DEGs were subjected to GO functional enrichment analysis (including biological processes, molecular functions, and cellular components) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, utilizing R software. Protein-protein interaction networks for the DEGs were generated using the STRING online database. Top hub genes were cross-referenced with genes related to ferroptosis from the FerrDb database to identify DEGs linked to ferroptosis in resistant melanoma cells. From the GEO database analysis, we identified the top 100 DEGs between BRAF V600E melanoma cell lines, including 50 downregulated and 50 upregulated DEGs. Using STRING and Cytoscape, we identified the top 10 hub genes: IL6, IL1B, CCL2, MMP2, TGFB2, EGFR, POSTN, SERPINE1, COL1A2, and MITF. Cross-referencing with the FerrDb database, we found that IL6 and EGFR are differentially expressed genes related to ferroptosis in resistant melanoma cells. Validation through clinical samples and in vitro experiments confirmed the high expression of the ferroptosis-related gene EGFR as a potential biomarker for resistance to targeted therapy in BRAFV600E melanoma. Bioinformatics analysis identified key resistance genes in BRAFV600E melanoma targeted therapy, demonstrating the impact of ferroptosis-related gene EGFR on the resistance of BRAFV600E melanoma.

Current Insights into the Role of UV Radiation-Induced Oxidative Stress in Melanoma Pathogenesis

Cutaneous melanoma accounts for the majority of skin cancer-related deaths, and its incidence increases each year. The growing number of melanoma cases, especially in advanced stages, poses a significant socio-medical challenge throughout the world. Extensive research on melanoma pathogenesis identifies UV radiation as the most important factor in melanocytic transformation. Oxidative effects of UV irradiation exert their influence on melanoma pathogenesis primarily through modification of nucleic acids, proteins, and lipids, further disrupting cellular signaling and cell cycle regulation. Its effects extend beyond melanocytes, leading to immunosuppression in the exposed skin tissue, which consequently creates conditions for immune surveillance evasion and further progression. In this review, we focus on the specific molecular changes observed in the UV-dependent oxidative stress environment and their biological consequences in the course of the disease, which have not been considered in previous reviews on melanoma. Nonetheless, data show that the exact role of oxidative stress in melanoma initiation and progression remains unclear, as it affects cancerous cells differently depending on the specific context. A better understanding of the pathophysiological basis of melanoma development holds promise for identifying potential targets, which could lead to effective melanoma prevention strategies.

MOCS, a novel classifier system integrated multimoics analysis refining molecular subtypes and prognosis for skin melanoma

PURPOSE

The present investigation focuses on Skin Cutaneous Melanoma (SKCM), a melanocytic carcinoma characterized by marked aggression, significant heterogeneity, and a complex etiological background, factors which collectively contribute to the challenge in prognostic determinations. We defined a novel classifier system specifically tailored for SKCM based on multiomics.

METHODS

We collected 423 SKCM samples with multi omics datasets to perform a consensus cluster analysis using 10 machine learning algorithms and verified in 2 independent cohorts. Clinical features, biological characteristics, immune infiltration pattern, therapeutic response and mutation landscape were compared between subtypes.

RESULTS

Based on consensus clustering algorithms, we identified two Multi-Omics-Based-Cancer-Subtypes (MOCS) in SKCM in TCGA project and validated in GSE19234 and GSE65904 cohorts. MOCS2 emerged as a subtype with poor prognosis, characterized by a complex immune microenvironment, dysfunctional anti-tumor immune state, high cancer stemness index, and genomic instability. MOCS2 exhibited resistance to chemotherapy agents like erlotinib and sunitinib while sensitive to rapamycin, NSC87877, MG132, and FH355. Additionally, ELSPBP1 was identified as the target involving in glycolysis and M2 macrophage infiltration in SKCM.

CONCLUSIONS

MOCS classification could stably predict prognosis of SKCM; patients with a high cancer stemness index combined with genomic instability may be predisposed to an immune exhaustion state.Communicated by Ramaswamy H. Sarma.

Exploring the In Vitro and In Vivo Therapeutic Potential of BRAF and MEK Inhibitor Combination in NRAS-Mutated Melanoma

INTRODUCTION

Patients with NRAS-mutant metastatic melanoma often have an aggressive disease requiring a fast-acting, effective therapy. The MEK inhibitor binimetinib shows an overall response rate of 15% in patients with NRAS-mutant melanoma, providing a backbone for combination strategies. Our previous studies demonstrated that in NRAS-mutant melanoma, the antitumor activity of the MEK inhibitor binimetinib was significantly potentiated by the BRAFV600E/K inhibitor encorafenib through the induction of ER stress, leading to melanoma cell death by apoptotic mechanisms. Encorafenib combined with binimetinib was well tolerated in a phase III trial showing potent antitumor activity in BRAF-mutant melanoma, making a rapid evaluation in NRAS-mutant melanoma imminently feasible. These data provide a mechanistic rationale for the evaluation of binimetinib combined with encorafenib in preclinical and clinical studies on NRAS-mutant metastatic melanoma.

METHODS

The combination of BRAFi plus MEKi was tested in a monolayer culture of patient-derived cell lines and in corresponding patient-derived tissue slice cultures of NRAS-mutant melanoma. To investigate the treatment in vivo, NSG (NOD. Cg-PrkdcscidIl2rgtm1Wjl/SzJ) mice were subcutaneously injected with three different BRAF wild-type melanoma models harboring oncogenic NRAS mutations and treated orally with encorafenib (6 mg/kg body weight, daily) with or without binimetinib (8 mg/kg body weight, twice daily). In parallel, an individual healing attempt was carried out by treating one patient with an NRAS-mutated tumor.

RESULTS

Encorafenib was able to enhance the inhibitory effect on cell growth of binimetinib only in the cell line SKMel147 in vitro. It failed to enhance the apoptotic effect found in two other NRAS-mutated cell lines. Encorafenib led to a hyperactivation of ERK which could be reduced with the combinational treatment. In two of the three patient-derived tissue slice culture models of NRAS-mutant melanomas, a slight tendency of a combinatorial effect was seen which was not significant. Encorafenib showed a slight induction of the ER stress genes ATF4, CHOP, and NUPR1. The combinational treatment was able to enhance this effect, but not significantly. In the mouse model, the combination therapy of encorafenib with binimetinib resulted in reduced tumor growth compared to the control and encorafenib groups; however, the best effect in terms of tumor growth inhibition was measured in the binimetinib therapy group. The therapy showed no effect in an individual healing attempt for a patient suffering from metastatic, therapy-refractory NRAS-mutated melanoma.

CONCLUSION

In in vitro and ex vivo settings, the combination therapy was observed to elicit a response; however, it did not amplify the efficacy observed with binimetinib alone, whereas in a patient, the combinational treatment remained ineffective. The preclinical in vivo data showed no increased combinatorial effect. However, the in vivo effect of binimetinib as monotherapy was unexpectedly high in the tested regimen. Nevertheless, binimetinib proved to be advantageous in the treatment of melanoma in vivo and led to high rates of apoptosis in vitro; hence, it still seems to be a good base for combination with other substances in the treatment of patients with NRAS-mutant melanoma.