Altered cell-surface glycans are established cancer biomarkers, yet no oncogenes have been identified within glycan biosynthesis machinery. This represents a critical gap, as defining a gene as a true oncogene, rather than merely a component of an oncogenic pathway, reveals targetable dependencies that can improve clinical decisions. To date, no gain-of-function mutations have been detected in glycogenes, and the search for such mutations is largely saturated. To address this gap, we developed a bioinformatic-experimental pipeline to identify copy number alteration (CNA)-based driver genes, overcoming noise from passenger genes. The approach recovered known oncogenes and tumor suppressors, while revealing novel candidates, including glyco-oncogenes. Focusing on the glycosphingolipid (GSL) biosynthetic pathway, we validated B4GALT5 as a bona fide glyco-oncogene whose genomic amplification drives proliferation, oncogene addiction, and poor prognosis, effects that can be reversed by targeted pathway inhibition. Mechanistic studies show that B4GALT5 promotes cancer cell survival via integrin-Src signaling under anchorage-independent conditions. Collectively, these findings establish glycosylation enzymes as a druggable oncogene class and provide a resource of high-confidence CNA-based cancer regulatory genes.

The Golgi apparatus functions as the central processing hub for proteins and lipids, orchestrating glycosylation, sorting, and secretion. Once viewed as a passive site of bulk enzyme recycling, the Golgi is now recognized as a highly dynamic, multimodular system in which intra-Golgi trafficking and glycan synthesis operate as tightly interdependent "Siamese twins." The classical cisternal maturation model, initially based on uniform COPI-mediated recycling, has evolved into the multimodular cisternal maturation (MCM) framework, revealing the coexistence of multiple, specialized recycling modules. Distinct sets of glycosyltransferases form coherent enzymatic modules, each maintained by dedicated retrograde pathways-some COPI-dependent, others COPI-independent-that ensure compartmental fidelity and enable differential regulation of glycan synthesis. These pathways are coordinated by adaptors, retainers, and lipid identity cues that collectively sustain Golgi polarity and adaptability to cellular and metabolic states. Disruption of this modular recycling logic leads to enzyme mislocalization, defective glycosylation, and disease, ranging from congenital disorders of glycosylation to oncogenic transformation. The transition from bulk to multimodular recycling thus redefines the Golgi as an integrated regulatory platform linking membrane trafficking to metabolic and signaling networks.

CtBP1-S/BARS (C-terminal binding protein 1-S/Brefeldin A ADP-Ribosylation Substrate) is a moonlighting protein with key roles in membrane trafficking and gene regulation. We show that CtBP1-S/BARS couples enzymatic lipid remodeling [lysophosphatidic acid (LPA)-to-phosphatidic acid (PA) conversion] with membrane deformation to drive fission and that this activity is directly controlled by metabolic ligands. CtBP1-S/BARS exists as a monomer or dimer. The monomeric, acyl-CoA-bound form drives membrane fission by coupling acyltransferase-dependent LPA-to-PA conversion with amphipathic helix insertion into PA-enriched membranes. Under metabolic stress, reduced nicotinamide adenine dinucleotide (NADH) binding triggers dimerization and structural rearrangements that disable fission, enabling the binding of transcription factors regulating apoptosis and energy metabolism. This NADH/acyl-CoA competition likely coordinates trafficking shutdown with gene expression programs through a single conformational change. In intact cells, increased NADH promotes nuclear accumulation of dimeric/tetrameric CtBP1-S/BARS, whereas elevated acyl-CoA favors the cytosolic, membrane-associated monomer, indicating that cofactor availability determines protein function under physiological and stress conditions. This work reveals the structural basis for integrating membrane transport with transcriptional control, demonstrating how evolution embeds distinct cellular functions into a unified molecular pathway.

Ca2+ influx into the trans-Golgi Network (TGN) promotes secretory cargo sorting by the Ca2+-ATPase SPCA1 and the luminal Ca2+ binding protein Cab45. Cab45 oligomerizes upon local Ca2+ influx, and Cab45 oligomers sequester and separate soluble secretory cargo from the bulk flow of proteins in the TGN. However, how this Ca2+ flux into the lumen of the TGN is achieved remains mysterious, as the cytosol has a nanomolar steady-state Ca2+ concentration. The TGN forms membrane contact sites (MCS) with the Endoplasmic Reticulum (ER), allowing protein-mediated exchange of molecular species such as lipids. Here, we show that the TGN export of secretory proteins requires the integrity of ER-TGN MCS and inositol 3 phosphate receptor (IP3R)-dependent Ca2+ fluxes in the MCS, suggesting Ca2+ transfer between these organelles. Using an MCS-targeted Ca2+ FRET sensor module, we measure the Ca2+ flow in these sites in real time. These data show that ER-TGN MCS facilitates the Ca2+ transfer required for Ca2+-dependent cargo sorting and export from the TGN, thus solving a fundamental question in cell biology.

Abstract Background The C-terminal-binding protein 1/brefeldin A ADP-ribosylation substrate (CtBP1/BARS) acts both as an oncogenic transcriptional co-repressor and as a fission inducing protein required for membrane trafficking and Golgi complex partitioning during mitosis, hence for mitotic entry. CtBP1/BARS overexpression, in multiple cancers, has pro-tumorigenic functions regulating gene networks associated with “cancer hallmarks” and malignant behavior including: increased cell survival, proliferation, migration/invasion, epithelial-mesenchymal transition (EMT). Structurally, CtBP1/BARS belongs to the hydroxyacid-dehydrogenase family and possesses a NAD(H)-binding Rossmann fold, which, depending on ligands bound, controls the oligomerization of CtBP1/BARS and, in turn, its cellular functions. Here, we proposed to target the CtBP1/BARS Rossmann fold with small molecules as selective inhibitors of mitotic entry and pro-tumoral transcriptional activities. Methods Structured-based screening of drug databases at different development stages was applied to discover novel ligands targeting the Rossmann fold. Among these identified ligands, N-(3,4-dichlorophenyl)-4-{[(4-nitrophenyl)carbamoyl]amino}benzenesulfonamide, called Comp.11, was selected for further analysis. Fluorescence spectroscopy, isothermal calorimetry, computational modelling and site-directed mutagenesis were employed to define the binding of Comp.11 to the Rossmann fold. Effects of Comp.11 on the oligomerization state, protein partners binding and pro-tumoral activities were evaluated by size-exclusion chromatography, pull-down, membrane transport and mitotic entry assays, Flow cytometry, quantitative real-time PCR, motility/invasion, and colony assays in A375MM and B16F10 melanoma cell lines. Effects of Comp.11 on tumor growth in vivo were analyzed in mouse tumor model. Results We identify Comp.11 as a new, potent and selective inhibitor of CtBP1/BARS (but not CtBP2). Comp.11 directly binds to the CtBP1/BARS Rossmann fold affecting the oligomerization state of the protein (unlike other known CtBPs inhibitors), which, in turn, hinders interactions with relevant partners, resulting in the inhibition of both CtBP1/BARS cellular functions: i) membrane fission, with block of mitotic entry and cellular secretion; and ii) transcriptional pro-tumoral effects with significantly hampered proliferation, EMT, migration/invasion, and colony-forming capabilities. The combination of these effects impairs melanoma tumor growth in mouse models. Conclusions This study identifies a potent and selective inhibitor of CtBP1/BARS active in cellular and melanoma animal models revealing new opportunities to study the role of CtBP1/BARS in tumor biology and to develop novel melanoma treatments.

Entry into mitosis requires not only correct DNA replication but also extensive cell reorganization, including the separation of the Golgi ribbon into isolated stacks. To understand the significance of pre-mitotic Golgi reorganization, we devised a strategy to first block Golgi segregation, with the consequent G2-arrest, and then force entry into mitosis. We found that the cells forced to enter mitosis with an intact Golgi ribbon showed remarkable cell division defects, including spindle multipolarity and binucleation. The spindle defects were caused by reduced levels at the centrosome of the kinase Aurora-A, a pivotal spindle formation regulator controlled by Golgi segregation. Overexpression of Aurora-A rescued spindle formation, indicating a crucial role of the Golgi-dependent recruitment of Aurora-A at the centrosome. Thus, our results reveal that alterations of the pre-mitotic Golgi segregation in G2 have profound consequences on the fidelity of later mitotic processes and represent potential risk factors for cell transformation and cancer development.

Circulating tumor cells (CTCs) are tumor cells that have penetrated the circulatory system preserving tumor properties and heterogeneity. Detection and characterization of CTCs has high potential clinical values and many technologies have been developed for CTC identification. These approaches remain challenged by the extraordinary rarity of CTCs and the difficulty of efficiently distinguishing cancer from the much larger number of white blood cells in the bloodstream. Consequently, there is still a need for efficient and rapid methods to capture the broad spectrum of tumor cells circulating in the blood. Herein, we exploit the peculiarities of cancer metabolism for discriminating cancer from WBCs. Using deuterated glucose and Raman microscopy we show that a) the known ability of cancer cells to take up glucose at greatly increased rates compared to non-cancer cells results in the lipid generation and accumulation into lipid droplets and, b) by contrast, leukocytes do not appear to generate visible LDs. The difference in LD abundance is such that it provides a reliable parameter for distinguishing cancer from blood cells. For LD sensitive detections in a cell at rates suitable for screening purposes, we test a polarization-sensitive digital holographic imaging (PSDHI) technique that detects the birefringent properties of the LDs. By using polarization-sensitive digital holographic imaging, cancer cells (prostate cancer, PC3 and hepatocarcinoma cells, HepG2) can be rapidly discriminated from leukocytes with reliability close to 100%. The combined Raman and PSDHI microscopy platform lays the foundations for the future development of a new label-free, simple and universally applicable cancer cells’ isolation method.

Nos últimos 15 anos o tratamento cirúrgico do câncer de mama foi revolucionado por alguns novos conceitos na história natural destes tumores. A impossibilidade de controlar a doença com uma cirurgia alargada, a identificação de tumores cada vez menores com o uso da mamografia, a possibilidade da "paciente atual" participar da escolha do tratamento, criaram as condições para um tratamento conservador. Os resultados retrospectivos e, especialmente, prospectivos, dos estudos sobre o tratamento conservador têm demonstrado que a terapia de combinação pode fornecer um adequado controle local do tumor. O Trial 1 de Milão, comparando a mastectomia de Halsted versus a QUART(quadrantectomia, dissecção axilare radioterapia), forneceu uma importante contribuição mostrando não existir diferenças na sobrevida global, período livre de doença e recidivas locais entre os dois tipos de tratamento.

The Golgi complex (GC) is the main station along the cell biosecretory pathway. Until now, mechanisms of intra-Golgi transport (IGT) have remained unclear. Herein, we confirm that the goodness-of-fit of the regression lines describing the exit of a cargo from the Golgi zone (GZ) corresponds to an exponential decay. When the GC was empty before the re-initiation of the intra-Golgi transport, this parameter of the curves describing the kinetics of different cargoes (which are deleted in Golgi vesicles) with different diffusional mobilities within the GZ as well as their exit from the GZ was maximal for the piecewise nonlinear regression, wherein the first segment was horizontal, while the second segment was similar to the exponential decay. The kinetic curve describing cargo exit from the GC per se resembled a linear decay. The Monte-Carlo simulation revealed that such curves reflect the role of microtubule growth in cells with a central GC or the random hovering of ministacks in cells lacking a microtubule. The synchronization of cargo exit from the GC already filled with a cargo using the wave synchronization protocol did not reveal the equilibration of cargo within a Golgi stack, which would be expected from the diffusion model (DM) of IGT. Moreover, not all cisternae are connected to each other in mini-stacks that are transporting membrane proteins. Finally, the kinetics of post-Golgi carriers and the important role of SNAREs for IGT at different level of IGT also argue against the DM of IGT.

Abstract Purpose Axillary Web Syndrome (AWS) is a common sequela after surgical axillary lymph node dissection (ALND) often manifesting with reduced range of motion (ROM) of the limb, which requires rehabilitation. Notwithstanding, a standardized rehabilitation protocol is currently lacking in clinical practice. Our primary objective was therefore to evaluate the effectiveness of the use of a snapping manual maneuver (SMM, used in our clinical practice) to increase ROM during abduction (ABD) when compared with a standardized stretching exercise (SSE) protocol. A three-year follow-up of the enrolled patients was also carried out to determine the incidence of Breast Cancer-Related Lymphedema (BCRL). Materials and methods Between July 2013 and January 2019, we conducted a single-blinded randomized clinical trial. A total of 60 patients, who underwent ALND in our hospital, came to our clinic under medical advice or on voluntary access and reported AWS symptoms. The patients were randomly assigned into two equally divided groups. The treatment of group one consists in the execution of a supervised SSEs protocol, while group two additionally received a manual snapping maneuver. Patients of both groups received two treatment sessions within two weeks. At the end of the session, they were asked to continue the exercises autonomously on a daily basis, three times per day, for one month. Results There were no statically significant differences in ROM at our one-month follow-up and the incidence of BCRL was equally distributed after three years. Conclusions The use of the manual snapping maneuver in addition to stretching once per week for two weeks does not appear to improve the outcome of the patients in comparison with stretching alone and does not appear to be related to lymphedema in our 3 years follow-up.

Importance Sentinel lymph node biopsy (SLNB) is the standard of care for axillary node staging of patients with early breast cancer (BC), but its necessity can be questioned since surgery for examination of axillary nodes is not performed with curative intent. Objective To determine whether the omission of axillary surgery is noninferior to SLNB in patients with small BC and a negative result on preoperative axillary lymph node ultrasonography. Design, Setting, and Participants The SOUND (Sentinel Node vs Observation After Axillary Ultra-Sound) trial was a prospective noninferiority phase 3 randomized clinical trial conducted in Italy, Switzerland, Spain, and Chile. A total of 1463 women of any age with BC up to 2 cm and a negative preoperative axillary ultrasonography result were enrolled and randomized between February 6, 2012, and June 30, 2017. Of those, 1405 were included in the intention-to-treat analysis. Data were analyzed from October 10, 2022, to January 13, 2023. Intervention Eligible patients were randomized on a 1:1 ratio to receive SLNB (SLNB group) or no axillary surgery (no axillary surgery group). Main Outcomes and Measures The primary end point of the study was distant disease–free survival (DDFS) at 5 years, analyzed as intention to treat. Secondary end points were the cumulative incidence of distant recurrences, the cumulative incidence of axillary recurrences, DFS, overall survival (OS), and the adjuvant treatment recommendations. Results Among 1405 women (median [IQR] age, 60 [52-68] years) included in the intention-to-treat analysis, 708 were randomized to the SLNB group, and 697 were randomized to the no axillary surgery group. Overall, the median (IQR) tumor size was 1.1 (0.8-1.5) cm, and 1234 patients (87.8%) had estrogen receptor–positive ERBB2 (formerly HER2 or HER2/neu ), nonoverexpressing BC. In the SLNB group, 97 patients (13.7%) had positive axillary nodes. The median (IQR) follow-up for disease assessment was 5.7 (5.0-6.8) years in the SLNB group and 5.7 (5.0-6.6) years in the no axillary surgery group. Five-year distant DDFS was 97.7% in the SLNB group and 98.0% in the no axillary surgery group (log-rank P = .67; hazard ratio, 0.84; 90% CI, 0.45-1.54; noninferiority P = .02). A total of 12 (1.7%) locoregional relapses, 13 (1.8%) distant metastases, and 21 (3.0%) deaths were observed in the SLNB group, and 11 (1.6%) locoregional relapses, 14 (2.0%) distant metastases, and 18 (2.6%) deaths were observed in the no axillary surgery group. Conclusions and Relevance In this randomized clinical trial, omission of axillary surgery was noninferior to SLNB in patients with small BC and a negative result on ultrasonography of the axillary lymph nodes. These results suggest that patients with these features can be safely spared any axillary surgery whenever the lack of pathological information does not affect the postoperative treatment plan. Trial Registration ClinicalTrials.gov Identifier: NCT02167490

The decision to enter mitosis requires not only the control of DNA replication but also additional and crucial preparatory steps such as, for example, partial disassembly of the Golgi complex during G2. The Golgi complex is fundamental for the processing and sorting of proteins and lipids in the secretory pathway. It is organized as stacks of cisternae laterally connected by tubules to form a continuous Golgi ribbon. During G2, the Golgi ribbon is unlinked into isolated stacks in preparation for cell division. This structural reorganization is necessary for entry into mitosis, indicating that a “Golgi mitotic checkpoint” controls the correct segregation of this organelle. To understand the physiological significance of the pre-mitotic Golgi unlinking, we devised a strategy to accumulate cells in G2 with an intact Golgi ribbon and then induce entry into mitosis. Here, we show that forcing the entry of cells into mitosis with an intact Golgi ribbon causes remarkable cell division defects, including spindle multipolarity and binucleation, favoring cell transformation. We also find that the cells entering mitosis with an intact Golgi ribbon show reduced levels at the centrosome of the kinase Aurora-A, a pivotal regulator of spindle formation. Overexpression of Aurora-A rescues spindle formation, indicating that the Golgi-dependent Aurora-A recruitment has a crucial role in spindle formation. Thus, our results show that alterations of the pre-mitotic Golgi segregation have profound consequences on the fidelity of the mitotic process, representing potential risk factors for cell transformation and cancer development.

The biosynthetic transport route that constitutes the secretory pathway plays a fundamental role in the cell, providing to the synthesis and transport of around one third of human proteins and most lipids. Signaling molecules within autoregulatory circuits on the intracellular membranes of the secretory pathway regulate these processes, especially at the level of the Golgi complex. Indeed, cancer cells can hijack several of these signaling molecules, and therefore also the underlying regulated processes, to bolster their growth or gain more aggressive phenotypes. Here, we review the most important autoregulatory circuits acting on the Golgi, emphasizing the role of specific signaling molecules in cancer. In fact, we propose to draw awareness to highlight the Golgi-localized regulatory systems as potential targets in cancer therapy.

Cancer is a disease resulting from aberrant communication between cells of a multicellular organism. The glycan coat that surrounds the cells is an important player in cellular communication. While altered cell surface glycans are known biomarkers for cancer, glycan biosynthesis itself has not been considered a potential oncogenic pathway. So, to understand the oncogenic potential of the glycan biosynthetic pathways we have analyzed the copy number alterations (CNA) of genes encoding for glycosylation regulators (glycogenes) in cancer genome datasets and identify novel glyco-oncogenes and glyco-tumor suppressor genes (TSGs). CNA of oncogenes and TSGs is an important cancer-associated genetic alteration that associates with worst prognosis. Nevertheless, identity of the driver genes in the copy number altered segments of the genome remains obscure in most cases. We developed a prioritization pipeline based on bioinformatic and experimental criteria to identify putative driver genes. In addition to correctly identifying several well-established oncogenes/TSGs, this pipeline discerns several novel oncogenes and TSGs, some of which are glycogenes. Further, among glyco-oncogenes there is an enrichment for glycosphingolipid biosynthetic pathway and trans-Golgi associated lysosomal sorting machinery and among glyco-TSGs there is an enrichment for early N-glycan biosynthetic enzymes. As a proof-of-principle we show that one of the identified glycooncogene B4GALT5, encoding a key enzyme in the glycosphingolipid pathway exhibits oncogenic property of promoting increased growth of hepatocellular carcinoma cells. Thus, this study identifies glycosylation pathways with oncoregulatory properties and opens up a new group of enzymes as potential therapeutic targets for cancer.

Cellular functions are controlled by an extensive regulatory network, within which one can distinguish two principal classes of circuits. One is involved in cellular responses to extracellular cues via membrane receptors facing the extracellular space, while the other consists of internal sensors, controllers and effectors that operate to maintain homeostasis, coordinate different cellular functions, and optimize its overall system’s performance. The former class of receptor signaling circuit has been investigated over the last decades in the context of many cell functions and it is well understood, while the latter has been studied much less extensively, or by comparison, neglected, at least in many areas, despite its fundamental importance in physiology and pathology. This article focuses mainly on the second class of circuits, and, in particular, on the internal control mechanisms operating in the biosynthetic membrane transport (BMT) apparatus, a fundamental cell module with a major role in the cellular organization. The BMT apparatus is responsible for the synthesis, folding, processing and delivery to their final cellular destinations of a third of the eukaryotic proteome. Through these functions, the transport apparatus maintains the correct morphology, composition and function of most cellular organelles by influencing the cell–cell and cell–environment communications. Moreover, the BMT interacts with other cellular modules like energy metabolism and autophagy in the execution of complex programs initiated by surface receptors, such as cell growth, migration and differentiation. We analyze the molecular composition, design principles, coordination with other modules, and significance in physiology and pathology of the control systems operating in the BMT.

G-protein-coupled receptors (GPCRs) and G-proteins have a range of roles in many physiological and pathological processes and are among the most studied signaling proteins. A plethora of extracellular stimuli can activate the GPCR and can elicit distinct intracellular responses through the activation of specific transduction pathways. For many years, biologists thought that GPCR signaling occurred entirely on the plasma membrane. However, in recent decades, many lines of evidence have proved that the GPCRs and G-proteins may reside on endomembranes and can start or propagate signaling pathways through the organelles that form the secretory route. How these alternative intracellular signaling pathways of the GPCR and G-proteins influence the physiological and pathological function of the endomembranes is still under investigation. Here, we review the general role and classification of GPCRs and G-proteins with a focus on their signaling pathways in the membrane transport apparatus.

Ca2+ influx into the trans-Golgi Network (TGN) promotes secretory cargo sorting by the Ca2+-ATPase SPCA1 and the luminal Ca2+ binding protein Cab45. Cab45 oligomerizes upon a local Ca2+ influx, and Cab45 oligomers sequester and separate soluble secretory cargo from the bulk flow of proteins in the TGN. However, how this Ca2+ flux into the lumen of the TGN is achieved remains elusive, as the cytosol has a very low steady-state Ca2+ concentration. The TGN forms membrane contact sites (MCS) with the Endoplasmic Reticulum (ER), whereby the close apposition of the two organelles allows the protein-mediated exchange of molecular species such as lipids. Here we show that the TGN export of Cab45 clients requires the integrity of ER-TGN MCS and IP3R-dependent Ca2+ fluxes in the MCS, suggesting Ca2+ transfer between these organelles. Using an MCS-targeted Ca2+ FRET sensor module, we measure the Ca2+ flow in these sites in real-time. These data show for the first time that ER-TGN MCS facilitates Ca2+ transfer required for SPCA1-dependent cargo sorting and export from the TGN, thus solving a fundamental question in cell biology. Summary The current study demonstrates that the trafficking of COMP and LyzC relies on Ca2+ flux between the endoplasmic reticulum (ER) and trans-Golgi Network (TGN). This process requires the activity of IP3 receptors, present in ER membranes, and depends on the integrity of the membrane contact site between these two organelles.

Neurons are highly polarized cells requiring precise regulation of trafficking and targeting of membrane proteins to generate and maintain different and specialized compartments, such as axons and dendrites. Disruption of the Golgi apparatus (GA) secretory pathway in developing neurons alters axon/dendritic formation. Therefore, detailed knowledge of the mechanisms underlying vesicles exiting from the GA is crucial for understanding neuronal polarity. In this study, we analyzed the role of Brefeldin A-Ribosylated Substrate (CtBP1-S/BARS), a member of the C-terminal-binding protein family, in the regulation of neuronal morphological polarization and the exit of membrane proteins from the Trans Golgi Network. Here, we show that BARS is expressed during neuronal development in vitro and that RNAi suppression of BARS inhibits axonal and dendritic elongation in hippocampal neuronal cultures as well as largely perturbed neuronal migration and multipolar-to-bipolar transition during cortical development in situ. In addition, using plasma membrane (PM) proteins fused to GFP and engineered with reversible aggregation domains, we observed that expression of fission dominant-negative BARS delays the exit of dendritic and axonal membrane protein-containing carriers from the GA. Taken together, these data provide the first set of evidence suggesting a role for BARS in neuronal development by regulating post-Golgi membrane trafficking.

The Golgi apparatus, the main glycosylation station of the cell, consists of a stack of discontinuous cisternae. Glycosylation enzymes are usually concentrated in one or two specific cisternae along the cis-trans axis of the organelle. How such compartmentalized localization of enzymes is achieved and how it contributes to glycosylation are not clear. Here, we show that the Golgi matrix protein GRASP55 directs the compartmentalized localization of key enzymes involved in glycosphingolipid (GSL) biosynthesis. GRASP55 binds to these enzymes and prevents their entry into COPI-based retrograde transport vesicles, thus concentrating them in the trans-Golgi. In genome-edited cells lacking GRASP55, or in cells expressing mutant enzymes without GRASP55 binding sites, these enzymes relocate to the cis-Golgi, which affects glycosphingolipid biosynthesis by changing flux across metabolic branch points. These findings reveal a mechanism by which a matrix protein regulates polarized localization of glycosylation enzymes in the Golgi and controls competition in glycan biosynthesis.