Glioblastoma multiforme (GBM), a high-grade astrocytic brain tumor, has highly aggressive and heterogeneous phenotypes with active cellular invasion, angiogenesis, and immune system modulation in the tumor microenvironment driven by complex oncogenic mutations. This abnormal disease progression could be attributed to extracellular vesicles (EVs) containing diverse bioactive molecules, including proteins, genetic materials, lipids, and metabolites. Importantly, GBM-related EVs have emerged as key mediators in cancer progression, acting as carriers for the transfer of oncogenic proteins such as epidermal growth factor receptor variant III (EGFRvIII) and genetic materials (DNA and RNA). Remarkably, recent progress in EV analysis has enabled its purification with high confidence by estimating the purity level of isolated EVs. Thus, mass spectrometry-based proteomic analysis could generate highly reliable vesicular proteomes. Glioblastoma EV proteome studies have revealed the specific increase in vesicular protein cargo due to their oncogenic transformation, and these EV proteins are closely associated with cancer invasion. Moreover, their proteomic data reflects the molecular alterations that occur in parental GBM and provides potent diagnostic information in a minimally invasive manner in liquid biopsy.Thus, proteomic analysis of GBM EVs could provide an increased understanding of their biological properties and activity in the GBM microenvironment, and provide significant implications for advanced approaches in the diagnosis of these intractable tumors.

Background: Melanoma is one of the most aggressive and metastatic skin cancers. Although overexpression of Dock180 and Elmo1 has been identified in various cancers, including glioma, ovarian cancer, and breast cancer, their expression and functions in melanoma remain unknown. Objective: This study aims to confirm the expression of Dock180 and Elmo1, their underlying mechanisms, and roles in melanoma. Methods: Both immunohistochemical staining and Western blotting were used to confirm expression of Dock180 and Elmo1 in human melanoma. To identify roles of Dock180 and Elmo1 in cell survival, apoptosis and migration, downregulation of Dock180 or Elmo1 in melanoma cells with small interfering RNA (siRNA) was performed. Results: We identified overexpression of Dock180 and Elmo1 in human melanoma compared to normal skin ex vivo. Inhibition of Dock180 or Elmo1 following siRNA in melanoma cells reduced cell viability and increased apoptosis as supported by increased proportion of cells with Annexin V-PE (+) staining and sub-G0/G1 peak in cell cycle analysis. Moreover, inhibition of Dock180 or Elmo1 regulated apoptosis-related proteins, showing downregulation of Bcl-2, caspase-3, and PARP and upregulation of Bax, PUMA, cleaved caspase-3, and cleaved PARP. Furthermore, knockdown of Dock180 and Elmo1 in melanoma cells reduced cell migration and changed cellular signaling pathways including ERK and AKT. Vemurafenib decreased cell viability in concentration-dependent manner, while transfection with Dock180- or Elmo1-specific siRNA in melanoma cells significantly reduced cell viability. Conclusion Our results suggest that both Dock180 and Elmo1 may be associated with cancer progression, and can be potential targets for treatment of melanoma.