Fenestrae in golgi and endoplasmic reticulum cisternae of human brain tumours

Golgi apparatus targeted therapy in cancer: Are we there yet?

Membrane trafficking within the Golgi apparatus plays a pivotal role in the intracellular transportation of lipids and proteins. Dysregulation of this process can give rise to various pathological manifestations, including cancer. Exploiting Golgi defects, cancer cells capitalise on aberrant membrane trafficking to facilitate signal transduction, proliferation, invasion, immune modulation, angiogenesis, and metastasis. Despite the identification of several molecular signalling pathways associated with Golgi abnormalities, there remains a lack of approved drugs specifically targeting cancer cells through the manipulation of the Golgi apparatus. In the initial section of this comprehensive review, the focus is directed towards delineating the abnormal Golgi genes and proteins implicated in carcinogenesis. Subsequently, a thorough examination is conducted on the impact of these variations on Golgi function, encompassing aspects such as vesicular trafficking, glycosylation, autophagy, oxidative mechanisms, and pH alterations. Lastly, the review provides a current update on promising Golgi apparatus-targeted inhibitors undergoing preclinical and/or clinical trials, offering insights into their potential as therapeutic interventions. Significantly more effort is required to advance these potential inhibitors to benefit patients in clinical settings.

Adaptation of the Golgi Apparatus in Cancer Cell Invasion and Metastasis

The Golgi apparatus plays a central role in normal cell physiology by promoting cell survival, facilitating proliferation, and enabling cell-cell communication and migration. These roles are partially mediated by well-known Golgi functions, including post-translational modifications, lipid biosynthesis, intracellular trafficking, and protein secretion. In addition, accumulating evidence indicates that the Golgi plays a critical role in sensing and integrating external and internal cues to promote cellular homeostasis. Indeed, the unique structure of the mammalian Golgi can be fine-tuned to adapt different Golgi functions to specific cellular needs. This is particularly relevant in the context of cancer, where unrestrained proliferation and aberrant survival and migration increase the demands in Golgi functions, as well as the need for Golgi-dependent sensing and adaptation to intrinsic and extrinsic stressors. Here, we review and discuss current understanding of how the structure and function of the Golgi apparatus is influenced by oncogenic transformation, and how this adaptation may facilitate cancer cell invasion and metastasis.

Mechanical model of Golgi apparatus

The Golgi apparatus has intrigued researchers since its discovery and despite the advances, there are still many open questions in regards to its shape and function. We propose a mechanical model of Golgi apparatus stack and explain its most elementary geometrical properties: the equilibrium number of cisternae, the stack size, and its general equilibrium shape. Combining both analytical and numerical methods we successfully reconstruct the stack morphology within the theory of bending elasticity. We demonstrate that energy-wise the stack prefers an overall bent shape and show strong evidence that the adhesion strength determines the equilibrium number of cisternae per stack. We explore the morphological role of fenestrations and discuss their impact on the overall stack structure. We also comment on the effects of the asymmetry in the composition of membrane leaflets on the shape of the cisternae and thus offer a broad steady-state study of the stack morphology and present a method that can be used also for other membrane-bound organelles.

Progressive sheet-to-tubule transformation is a general mechanism for endoplasmic reticulum partitioning in dividing mammalian cells

During mitosis, ER network reorganization can lead to packing of the ER into tight concentric layers at the cell cortex and occurs in tandem with rounding of the cell. Morphometric and 3D EM analysis shows that in addition to reorganization, ER sheets undergo transformation toward more fenestrated and tubular forms before anaphase in mammalian cells.

The endoplasmic reticulum (ER) is both structurally and functionally complex, consisting of a dynamic network of interconnected sheets and tubules. To achieve a more comprehensive view of ER organization in interphase and mitotic cells and to address a discrepancy in the field (i.e., whether ER sheets persist, or are transformed to tubules, during mitosis), we analyzed the ER in four different mammalian cell lines using live-cell imaging, high-resolution electron microscopy, and three dimensional electron microscopy. In interphase cells, we found great variation in network organization and sheet structures among different cell lines. In mitotic cells, we show that the ER undergoes both spatial reorganization and structural transformation of sheets toward more fenestrated and tubular forms. However, the extent of spatial reorganization and sheet-to-tubule transformation varies among cell lines. Fenestration and tubulation of the ER correlates with a reduced number of membrane-bound ribosomes.