The covert symphony: cellular and molecular accomplices in breast cancer metastasis

Breast cancer has emerged as the most commonly diagnosed cancer and primary cause of cancer-related deaths among women worldwide. Although significant progress has been made in targeting the primary tumor, the effectiveness of systemic treatments to prevent metastasis remains limited. Metastatic disease continues to be the predominant factor leading to fatality in the majority of breast cancer patients. The existence of a prolonged latency period between initial treatment and eventual recurrence in certain patients indicates that tumors can both adapt to and interact with the systemic environment of the host, facilitating and sustaining the progression of the disease. In order to identify potential therapeutic interventions for metastasis, it will be crucial to gain a comprehensive framework surrounding the mechanisms driving the growth, survival, and spread of tumor cells, as well as their interaction with supporting cells of the microenvironment. This review aims to consolidate recent discoveries concerning critical aspects of breast cancer metastasis, encompassing the intricate network of cells, molecules, and physical factors that contribute to metastasis, as well as the molecular mechanisms governing cancer dormancy

Atlastin regulates store-operated calcium entry for nerve growth factor-induced neurite outgrowth

Homotypic membrane fusion of the endoplasmic reticulum (ER) is mediated by a class of dynamin-like GTPases known as atlastin (ATL). Depletion of or mutations in ATL cause an unbranched ER morphology and hereditary spastic paraplegia (HSP), a neurodegenerative disease characterized by axon shortening in corticospinal motor neurons and progressive spasticity of the lower limbs. How ER shaping is linked to neuronal defects is poorly understood. Here, we show that dominant-negative mutants of ATL1 in PC-12 cells inhibit nerve growth factor (NGF)-induced neurite outgrowth. Overexpression of wild-type or mutant ATL1 or depletion of ATLs alters ER morphology and affects store-operated calcium entry (SOCE) by decreasing STIM1 puncta formation near the plasma membrane upon calcium depletion of the ER. In addition, blockage of the STIM1-Orai pathway effectively abolishes neurite outgrowth of PC-12 cells stimulated by NGF. These results suggest that SOCE plays an important role in neuronal regeneration, and mutations in ATL1 may cause HSP, partly by undermining SOCE

Inside-out Ca2+ signalling prompted by STIM1 conformational switch

Store-operated Ca(2+) entry mediated by STIM1 and ORAI1 constitutes one of the major Ca(2+) entry routes in mammalian cells. The molecular choreography of STIM1–ORAI1 coupling is initiated by endoplasmic reticulum (ER) Ca(2+) store depletion with subsequent oligomerization of the STIM1 ER-luminal domain, followed by its redistribution towards the plasma membrane to gate ORAI1 channels. The mechanistic underpinnings of this inside-out Ca(2+) signalling were largely undefined. By taking advantage of a unique gain-of-function mutation within the STIM1 transmembrane domain (STIM1-TM), here we show that local rearrangement, rather than alteration in the oligomeric state of STIM1-TM, prompts conformational changes in the cytosolic juxtamembrane coiled-coil region. Importantly, we further identify critical residues within the cytoplasmic domain of STIM1 (STIM1-CT) that entail autoinhibition. On the basis of these findings, we propose a model in which STIM1-TM reorganization switches STIM1-CT into an extended conformation, thereby projecting the ORAI-activating domain to gate ORAI1 channels

The Role of CRAC Channels in Lymphatic Endothelial Cells Responding to Fluid Shear Stress and Histamine

The lymphatic system maintains body fluid homeostasis, lipid absorption, and immune surveillance by transporting fluid, macromolecules, and cells back to the circulatory system. Disrupted lymphatic integrity or pumping causes numerous severe diseases, including lymphedema and inflammatory disorders. Calcium (Ca^2^+) release-activated Ca^2^+ (CRAC) channels mediate the ubiquitous store-operated Ca^2^+ entry (SOCE) and are essential for various cellular processes (e.g., T cell activation, mast cell degranulation, and endothelial cell proliferation). However, the role of CRAC channels in the lymphatic system remains unclear. In this dissertation we addressed the function of CRAC channels in cultured lymphatic endothelial cells (LECs) responding to fluid shear stress (FSS) and histamine. In the model of FSS stimulation, we described the Ca 2+ dynamics triggered by FSS in LECs and determined the necessity of CRAC channels, formed by Orai1 and STIM1 proteins, in the Ca^2^+ signaling utilizing pharmacological blockers and RNA interference (RNAi). By using confocal imaging and RNAsequencing (RNA-Seq), we further found that the activation of nuclear factor of activated T-cells (NFAT) and transcriptional reprogramming downstream of FSS were also dependent on CRAC channels. Our quantitative PCR (qPCR) and enzyme-linked immunosorbent assay (ELISA) data also showed that blocking CRAC channels abolished the regulation of interleukin-8 (IL-8) secretion by FSS, indicating that CRACchannels are required in FSS-induced cytokine modulation. In addition, we studied the Ca^2^+ signaling in LECs upon histamine stimulation using single-cell Ca^2^++ imaging and discovered that histamine evoked the intracellular Ca^2^+ store release through H1 receptors (H1R) and phospholipase C (PLC). The subsequent sustained Ca^2^+ entry from the extracellular solution triggered by histamine was mediated by CRAC channels. We also examined the lymphatic endothelial barrier function after histamine stimulation and found that the hyperpermeability and VE-cadherin disruption caused by histamine was attenuated by CRAC channel blockers. Moreover, the knockdown of CRAC channels diminished the inflammatory cytokine expression after histamine stimulation in LECs. In summary, this study demonstrated the essential role of CRAC channels in both mechanotransduction and histamine-elicited inflammatory responses in LECs

Estimating p-y curves for clays by CPTU method : framework and empirical study

Despite its wide use as a tool in foundation design, the piezocone penetration test (CPTU) has been rarely recommended to work for design and analysis of laterally loaded piles. Obtaining lateral response of pile foundations is a complicated engineering problem, especially in nonhomogeneous soils. This paper presents a review of the relationship between the piezocone test and the bearing response of laterally loaded piles and introduces a framework for estimating p-y curves for clays directly using CPTU parameters. To validate this method, full-scale lateral load tests of bored piles with corresponding CPTU tests in Jiangsu soil deposits were conducted and data were compared with the predicted results. In addition, case histories were further considered in detail to study the application of the proposed method for different field conditions. The results predicted by the proposed CPTU-based p-y curve agreed relatively well with the measured results. The proposed method can provide a fast and effective design tool that can be applied to clayey soils with full consideration of soil profiles along the pileembedded depth.Accepted versio