Dual VEGF/PDGF knockdown suppresses vasculogenic mimicry formation in choroidal melanoma cells via the Wnt5a/β-catenin/AKT signaling pathway

Artesunate inhibits vasculogenic mimicry in choroidal melanoma through HIF-1 α/ VEGF/PDGF pathway

Choroidal melanoma (CM), a highly metastatic eye tumor, exhibits vasculogenic mimicry (VM) facilitated by hypoxia-induced angiogenesis. This study explored the inhibitory impact of the anti-malarial drug Artesunate (ART) on CM VM through modulation of the HIF-1α/VEGF/PDGF pathway. Immunohistochemistry (IHC) confirmed VM in CM with elevated VEGF and PDGF expression. Hypoxia promoted CM proliferation, upregulating HIF-1α, VEGF and PDGF. VEGF and PDGF enhanced CM migration, invasion and VM, with HIF-1α playing a crucial role. ART mitigated VM formation by suppressing the HIF-1α/VEGF/PDGF pathway, highlighting its potential as an anti-tumor agent in CM.

Integrating network pharmacology, molecular docking and experimental verification to reveal the mechanism of artesunate in inhibiting choroidal melanoma

Background

Artesunate (ART), a natural compound derived from Artemisia annua, has shown promising clinical potentials in the treatment of various tumors, but the exact mechanism is unclear. Choroidal melanoma (CM) is a major malignant ocular tumor in adults, known for its significant malignancy and poor prognosis, with limited efficacy in current treatments. This study explored the anti-CM effects and mechanisms of ART using a combination of network pharmacology, molecular docking and experimental validation.

Methods

Potential targets of ART were screened in PubChem, Swiss Target Prediction and Traditional Chinese Medicine Systems Pharmacology (TCMSP) Database Analysis Platform databases, while target genes related to CM prognosis were selected from Online Mendelian Inheritance in Man (OMIM), GeneCards and DisGeNET databases. The intersection of these two groups of datasets yielded the target genes of ART involved in CM. Protein-protein interaction (PPI) network analysis of the intersecting targets, as well as Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, were conducted to identify core targets and critical pathways. Molecular docking methods were performed to predict the binding interactions between ART and core targets. The effects of ART on CM were evaluated through CCK8, colony formation, transwell, as well as flow cytometry assays to detect apoptosis, cell cycle, reactive oxygen species (ROS). Western blot (WB) assays were conducted to investigate the impact of ART on key proteins and pathways associated with CM. Finally, in vivo assays were conducted to further validate the effects of ART on subcutaneous tumors in nude mice.

Results

Research has shown that key pathways and core targets for ART in treating CM were identified through a network pharmacology approach. Molecular docking results verified the strong binding affinity between ART and these core targets. The analysis and predicted results indicated that ART primarily exerted its effects on CM through various tumor-related pathways like apoptosis. The assays in vitro confirmed that ART significantly inhibited the proliferation and migration of CM cells. This was achieved by promoting apoptosis through activation of the p53 signaling pathway, causing cell cycle arrest at the G0/G1 phase by inhibiting the PI3K/AKT/mTOR signaling pathway and increasing the intracellular level of ROS by activating the NRF2/HO-1 signaling pathway. Additionally, the assays in vivo further validated the significant proliferation-inhibitory effect of ART on CM.

Conclusion

This study, making the initial exploration, illustrated through network pharmacology combined with molecular docking and in vitro/in vivo assays, confirmed that ART exerted potential anti-cancer effects on CM by promoting apoptosis, inducing cell cycle arrest and increasing intracellular levels of ROS. These findings suggested that ART held significant therapeutic potential for CM.

VEGF/VEGFR axis and its signaling in melanoma: Current knowledge toward therapeutic targeting agents and future perspectives

Melanoma is responsible for most skin cancer-associated deaths globally. The progression of melanoma is influenced by a number of pathogenic processes. Understanding the VEGF/VEGFR axis, which includes VEGF-A, PlGF, VEGF-B, VEGF-C, and VEGF-D and their receptors, VEGFR-1, VEGFR-2, and VEGFR-3, is of great importance in melanoma due to its crucial role in angiogenesis. This axis generates multifactorial and complex cellular signaling, engaging the MAPK/ERK, PI3K/AKT, PKC, PLC-γ, and FAK signaling pathways. Melanoma cell growth and proliferation, migration and metastasis, survival, and acquired resistance to therapy are influenced by this axis. The VEGF/VEGFR axis was extensively examined for their potential as diagnostic/prognostic biomarkers in melanoma patients and results showed that VEGF overexpression can be associated with unfavorable prognosis, higher level of tumor invasion and poor response to therapy. MicroRNAs linking to the VEGF/VEGFR axis were identified and, in this review, divided into two categories according to their functions, some of them promote melanoma angiogenesis (promotive group) and some restrict melanoma angiogenesis (protective group). In addition, the approach of treating melanoma by targeting the VEGF/VEGFR axis has garnered significant interest among researchers. These agents can be divided into two main groups: anti-VEGF and VEGFR inhibitors. These therapeutic options may be a prominent step along with the modern targeting and immune therapies for better coverage of pathological processes leading to melanoma progression and therapy resistance.

Pan-cancer dissection of vasculogenic mimicry characteristic to provide potential therapeutic targets

Introduction

Vasculogenic mimicry (VM) represents a novel form of tumor angiogenesis that is associated with tumor invasiveness and drug resistance. However, the VM landscape across cancer types remains poorly understood. In this study, we elucidate the characterizations of VM across cancers based on multi-omics data and provide potential targeted therapeutic strategies.

Methods

Multi-omics data from The Cancer Genome Atlas was used to conduct comprehensive analyses of the characteristics of VM related genes (VRGs) across cancer types. Pan-cancer vasculogenic mimicry score was established to provide a depiction of the VM landscape across cancer types. The correlation between VM and cancer phenotypes was conducted to explore potential regulatory mechanisms of VM. We further systematically examined the relationship between VM and both tumor immunity and tumor microenvironment (TME). In addition, cell communication analysis based on single-cell transcriptome data was used to investigate the interactions between VM cells and TME. Finally, transcriptional and drug response data from the Genomics of Drug Sensitivity in Cancer database were utilized to identify potential therapeutic targets and drugs. The impact of VM on immunotherapy was also further clarified.

Results

Our study revealed that VRGs were dysregulated in tumor and regulated by multiple mechanisms. Then, VM level was found to be heterogeneous among different tumors and correlated with tumor invasiveness, metastatic potential, malignancy, and prognosis. VM was found to be strongly associated with epithelial-mesenchymal transition (EMT). Further analyses revealed cancer-associated fibroblasts can promote EMT and VM formation. Furthermore, the immune-suppressive state is associated with a microenvironment characterized by high levels of VM. VM score can be used as an indicator to predict the effect of immunotherapy. Finally, seven potential drugs targeting VM were identified.

Conclusion

In conclusion, we elucidate the characteristics and key regulatory mechanisms of VM across various cancer types, underscoring the pivotal role of CAFs in VM. VM was further found to be associated with the immunosuppressive TME. We also provide clues for the research of drugs targeting VM. Our study provides an initial overview and reference point for future research on VM, opening up new avenues for therapeutic intervention.

Melanoma Tumour Vascularization and Tissue-Resident Endothelial Progenitor Cells

The aggressiveness of solid cancers, such as melanoma, relies on their metastatic potential. It has become evident that this key cause of mortality is largely conferred by the tumour-associated stromal cells, especially endothelial cells. In addition to their essential role in the formation of the tumour vasculature, endothelial cells significantly contribute to the establishment of the tumour microenvironment, thus enabling the dissemination of cancer cells. Melanoma tumour vascularization occurs through diverse biological processes. Vasculogenesis is the formation of de novo blood vessels from endothelial progenitor cells (EPCs), and recent research has shown the role of EPCs in melanoma tumour vascularization. A more detailed understanding of the complex role of EPCs and how they contribute to the abnormal vessel structures in tumours is of importance. Moreover, anti-angiogenic drugs have a limited effect on melanoma tumour vascularization, and the role of these drugs on EPCs remains to be clarified. Overall, targeting cancer vasculature remains a challenge, and the role of anti-angiogenic drugs and combination therapies in melanoma, a focus of this review, is an area of extensive exploration.