Upregulation of COPB2 Promotes Prostate Cancer Proliferation and Invasion Through the MAPK/TGF-β Signaling Pathway

Adaptations of membrane trafficking in cancer and tumorigenesis

Membrane trafficking, a fundamental cellular process encompassing the transport of molecules to specific organelles, endocytosis at the plasma membrane and protein secretion, is crucial for cellular homeostasis and signalling. Cancer cells adapt membrane trafficking to enhance their survival and metabolism, and understanding these adaptations is vital for improving patient responses to therapy and identifying therapeutic targets. In this Review, we provide a concise overview of major membrane trafficking pathways and detail adaptations in these pathways, including COPII-dependent endoplasmic reticulum (ER)-to-Golgi vesicle trafficking, COPI-dependent retrograde Golgi-to-ER trafficking and endocytosis, that have been found in cancer. We explore how these adaptations confer growth advantages or resistance to cell death and conclude by discussing the potential for utilising this knowledge in developing new treatment strategies and overcoming drug resistance for cancer patients.

The role of CaMKK2 in Golgi-associated vesicle trafficking

Calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) is a serine/threonine-protein kinase, that is involved in maintaining various physiological and cellular processes within the cell that regulate energy homeostasis and cell growth. CaMKK2 regulates glucose metabolism by the activation of downstream kinases, AMP-activated protein kinase (AMPK) and other calcium/calmodulin-dependent protein kinases. Consequently, its deregulation has a role in multiple human metabolic diseases including obesity and cancer. Despite the importance of CaMKK2, its signalling pathways and pathological mechanisms are not completely understood. Recent work has been aimed at broadening our understanding of the biological functions of CaMKK2. These studies have uncovered new interaction partners that have led to the description of new functions that include lipogenesis and Golgi vesicle trafficking. Here, we review recent insights into the role of CaMKK2 in membrane trafficking mechanisms and discuss the functional implications in a cellular context and for disease.

SENP6-Mediated deSUMOylation of VEGFR2 Enhances Its Cell Membrane Transport in Angiogenesis

Angiogenesis is a significant pathogenic characteristic of diabetic microangiopathy. Advanced glycation end products (AGEs) are considerably elevated in diabetic tissues and can affect vascular endothelial cell shape and function. Regulation of the vascular endothelial growth factor (VEGF)-VEGF receptor 2 (VEGFR2) signaling pathway is a critical mechanism in the regulation of angiogenesis, and VEGFR2 activity can be modified by post-translational changes. However, little research has been conducted on the control of small ubiquitin-related modifier (SUMO)-mediated VEGFR2 alterations. The current study investigated this using human umbilical vein endothelial cells (HUVECs) in conjunction with immunoblotting and immunofluorescence. AGEs increased Nrf2 translocation to the nucleus and promoted VEGFR2 expression. They also increased the expression of sentrin/SUMO-specific protease 6 (SENP6), which de-SUMOylated VEGFR2, and immunofluorescence indicated a reduction in VEGFR2 accumulation in the Golgi and increased VEGFR2 transport from the Golgi to the cell membrane surface via the coatomer protein complex subunit beta 2. VEGFR2 on the cell membrane was linked to VEGF generated by pericytes, triggering the VEGF signaling cascade. In conclusion, this study demonstrates that SENP6 regulates VEGFR2 trafficking from the Golgi to the endothelial cell surface. The SENP6-VEGFR2 pathway plays a critical role in pathological angiogenesis.