Shedding of bevacizumab in tumour cells-derived extracellular vesicles as a new therapeutic escape mechanism in glioblastoma

Revisiting the Role of Exosomes in Colorectal Cancer: Where Are We Now?

Exosomes (Exos) are nano-sized extracellular vesicles constitutively released by both prokaryotic and eukaryotic cells. Their role as inter-cellular messengers involved in both physiological and pathological processes has overwhelmingly come to light in the last decade, and their contribution to cancerogenesis and tumor metastasis is under intensive investigation. Here we review the most recent information concerning Exos in colorectal cancer (CRC) and focus on their effects on tumor microenvironment and the immune system, as well as unravel their role in the formation of the pre-metastatic niche and in drug resistance. Such a recent knowledge on Exos depicts their potential translations into the clinical arena, either as an alternative tool of “liquid biopsy” or novel therapeutic approaches for CRC. However, due to the limited data available from clinical trials, they need further validations before addressing their putative application in oncology.

Roles of Extracellular Vesicles in High-Grade Gliomas: Tiny Particles with Outsized Influence

High-grade gliomas, particularly glioblastomas (grade IV), are devastating diseases with dismal prognoses; afflicted patients seldom live longer than 15 months, and their quality of life suffers immensely. Our current standard-of-care therapy has remained essentially unchanged for almost 15 years, with little new therapeutic progress. We desperately need a better biologic understanding of these complicated tumors in a complicated organ. One area of rejuvenated study relates to extracellular vesicles (EVs)-membrane-enclosed nano- or microsized particles that originate from the endosomal system or are shed from the plasma membrane. EVs contribute to tumor heterogeneity (including the maintenance of glioma stem cells or their differentiation), the impacts of hypoxia (angiogenesis and coagulopathies), interactions amid the tumor microenvironment (concerning the survival of astrocytes, neurons, endothelial cells, blood vessels, the blood-brain barrier, and the ensuing inflammation), and influences on the immune system (both stimulatory and suppressive). This article reviews glioma EVs and the ways that EVs manifest themselves as autocrine, paracrine, and endocrine factors in proximal and distal intra- and intercellular communications. The reader should note that there is much controversy, and indeed confusion, in the field over the exact roles for EVs in many biological processes, and we will engage some of these difficulties herein.

NCK1 promotes the angiogenesis of cervical squamous carcinoma via Rac1/PAK1/MMP2 signal pathway

OBJECTIVE

The study was to explore the roles of Nck1 in the angiogenesis of cervical squamous cell carcinoma (CSCC).

METHODS

mRNA and protein levels were evaluated with real-time quantitative PCR and immunohistochemisty/western blotting respectively. The cancer microvessel density (MVD) was assayed with CD34 endothelial labeling. Nck1 gene knock-in (SiHa-Nck1+) and knock-down (SiHa-Nck1-) were achieved by gene transfection and siRNA respectively. Protein level from cellular supernatant was measured with ELISA. Proliferation, migration and tube formation of the Human Umbilical Vein Endothelial cells (HUVECs) were evaluated by CCK-8 cell viability assay, transwell chamber assay and in vitro Matrigel tubulation assay respectively.

RESULTS

Nck1 level gradually increased from normal cervical epithelia to high-grade CIN, overexpressed in CSCC and was associated with cancer MVD. The ability of proliferation, migration and tube formation of HUVECs was enhanced in SiHa-Nck1+-treated while decreased in SiHa-NcK1--treated cells compared to SiHa-control-treated cells. Mechanistically, RAC1-GTP, p-PAK1 and MMP2 were increased in SiHa-NCK1+ cells and pretreatment with the Rac1 inhibitor (NSC23766) significantly decreased their levels. Furthermore, inhibition of PAK1 reduced MMP2 level in SiHa-Nck1+ cells whereas the level of Rac1-GTP was unaltered. Also, inhibition of Rac1 or PAK1 impaired angiogenesis-inducing capacity of cancer cells.

CONCLUSIONS

Nck1 promotes the angiogenesis-inducing capacity of CSCC via the Rac1/PAK1/MMP2 signal pathway.