Product Citations: 255

PCK2, which encodes mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-M), is upregulated in various cancers. We demonstrated high expression of PEPCK-M in approximately half of triple-negative breast cancers (TNBCs) previously. TNBC is associated with an aggressive phenotype and a high metastasis rate. In this study, we investigated the role of PCK2 in TNBC. PCK2 knockdown suppressed proliferation and mTOR signaling in TNBC cells. In addition, cell invasion/migration ability and the expression of epithelial-to-mesenchymal transition (EMT) markers were positively correlated with PCK2 expression in TNBC cells via regulation of transforming growth factor-β (TGF-β)/SMAD3 signaling. SMAD3 was positively regulated by PCK2 in TNBC cells. Knockdown of SMAD3 in PCK2-overexpressing TNBC cells reduced the expression levels of EMT markers, Snail and Slug, and suppressed cell invasion/migration. In addition, PCK2 knockdown attenuated the stimulatory effect of TGF-β on SMAD3 phosphorylation in TNBC cells. PEPCK-M promotes the protein and mRNA expression of SMAD3 via competitive binding to tripartite motif-containing 67 (TRIM67), an E3 ubiquitin ligase, to reduce SMAD3 ubiquitination, which leads to promoting nuclear translocation of SMAD3 and autoregulation of SMAD3 transcription. Moreover, high PCK2 mRNA expression was significantly associated with poor survival in TNBC patients. In conclusion, our study revealed for the first time that PCK2 activates TGF-β/SMAD3 signaling by regulating the expression and phosphorylation of SMAD3 by inhibiting TRIM67-mediated SMAD3 ubiquitination and promoting the stimulatory effect of TGF-β to promote TNBC invasion. The regulatory effect of PCK2 on mTOR and TGF-β/SMAD3 signaling suggests that PCK2 is a potential therapeutic target for suppressing TNBC progression.

  • WB
  • Cancer Research

hiPSC-derived cardiac fibroblasts dynamically enhance the mechanical function of hiPSC-derived cardiomyocytes on an engineered substrate.

In Frontiers in Bioengineering and Biotechnology on 9 June 2025 by Josvai, M., Lawson, J., et al.

Cardiac fibroblasts deposit and turnover the extracellular matrix in the heart, as well as secrete soluble factors that play critical roles in development, homeostasis, and disease. Coculture of CFs and human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (CMs) enhances CM mechanical output, yet the mechanism remains unclear.
Here, we use an in vitro engineered platform to compare the effects on CM mechanical function of direct CM-CF Coculture and soluble signaling alone through CF Conditioned Medium to a CM Only monoculture. Mechanical analysis is performed using digital image correlation and custom software to quantify the coordination and organization of CM contractile behavior.
CM-CF Coculture induces larger CM contractile strains, and an increased rate of spontaneous contraction compared to CM Only. Additionally, CM-CF Cocultures have increased contractile anisotropy and myofibril alignment and faster kinetics. The paracrine effects of fibroblast conditioned medium (FCM) are sufficient to induce larger contractile strains and faster contraction kinetics with these effects remaining after the removal of FCM. However, FCM does not influence CM spontaneous rate, contractile alignment, anisotropy, or relaxation kinetics compared to CM Only control.
These data suggest that hiPSC-CFs exert dynamic and multifactorial effects on the mechanical function of hiPSC-CMs and highlight the importance of CFs in both the native heart and in vitro cardiac models. Further, this work demonstrates the applicability of the coculture-conditioned medium-monoculture paradigm to decouple the effects of paracrine factor and cell-cell signaling on hiPSC-CM mechanical function and maturation.
Copyright © 2025 Josvai, Lawson, Kanade, Kalluri, Anderson, Zhang, Stempien, Eckhardt, Kamp and Crone.

  • Cardiovascular biology

The proteasome maturation factor POMP moonlights as a stress-induced transcriptional regulator

Preprint on BioRxiv : the Preprint Server for Biology on 27 April 2025 by Giandomenico, S. L., Mueller, M., et al.

Summary Proteostasis - the maintenance of proteins at proper concentrations, conformations, and subcellular locations - is essential for cellular function and is governed by tightly regulated protein synthesis and degradation pathways. The Proteasome Maturation Protein (POMP) is a key chaperone involved in assembling the proteasome, the primary complex responsible for protein degradation. Despite the conserved role of POMP, its loss produces contrasting proteostatic effects in yeast and mammalian cells, pointing to additional, unexplored functions. In this study, we investigated the possibility that POMP plays a moonlighting role in proteostasis regulation. We discovered that upon proteasome disruption, POMP rapidly accumulates in the nucleolus in a manner dependent on HSF1 and reactive oxygen species (ROS). Proteomic analysis of POMP interactors revealed RNA processing factors and transcriptomic profiling showed that nucleolar POMP orchestrates a protective transcriptional program. Our findings indicate POMP is a built-in sensor and effector within the proteasome assembly pathway, capable of buffering disturbances in proteasome function through a novel, non-canonical role. Notably, this mechanism is developmentally controlled and active in neurodegenerative disease contexts. Abstract Figure

  • WB
  • Biochemistry and Molecular biology

Aberrant formation of long-range projections across different neurodevelopmental disorders converges on molecular and cellular nexuses

Preprint on BioRxiv : the Preprint Server for Biology on 16 April 2025 by Furlanetto, F., Segura, A., et al.

Summary Establishing long-range connections during human brain development is an intricate multi-step process disturbed in many neurodevelopmental disorders (NDDs). The aberrant formation of these connections is caused by mutations in a plethora of different genes with distinct molecular functions, triggering the question of whether there are common key downstream mediators at which different pathologies are converging. We employed brain organoids to model early human brain developmental aspects of Coffin-Siris-like 9, Opitz BBB/G, and Pitt-Hopkins syndromes. These NDDs are caused by mutations in SOX11 , MID1 , and TCF4 respectively, and are characterized by a multitude of distinct symptoms yet share alterations in long-range projections as a common feature. Here, we uncover that mutations in all three genes phenotypically converge, showing impaired neurite extension with increased tortuosity and decreased growth speed resulting in shorter beelines. Moreover, the mutant neurites exhibit a decrease in growth persistence providing a conceptual framework explaining why long- but not short-range connections are affected. Correlating with the converging cellular phenotype, molecular characterization revealed a striking convergence on signaling pathways implicated in the interaction of neurites with their extracellular environment. In-silico modeling and perturbation of neurite outgrowth suggest that altered neurite-extracellular environment interactions are sufficient to recapitulate the mutant phenotypes but also facilitate the prediction of specific parameters causing disturbed neurite growth in mutant neurons.

Phospholipase D6 (PLD6) is a critical enzyme involved in mitochondrial fusion with a key role in spermatogenesis. However, the role of PLD6 in cancer remains unknown. Notably, Wnt signaling, energy metabolism and mitochondrial function show complex interactions in colorectal cancer (CRC) progression. Here we found that PLD6 is highly expressed in CRC and positively correlated with poor prognosis. We present a novel function of PLD6 in activating Wnt/β-catenin signaling by enhancing mitochondrial metabolism. PLD6 depletion suppresses the oncogenic properties of CRC cells and impairs mitochondrial respiration, leading to reduced mitochondrial length, membrane potential, calcium levels and reactive oxygen species. PLD6 depletion also disrupts mitochondrial metabolic reprogramming by inhibiting the tricarboxylic acid cycle and mitochondrial oxidative phosphorylation, resulting in altered intracellular levels of citrate and acetyl-CoA-both key modulators of Wnt/β-catenin activation. PLD6-mediated acetyl-CoA production enhances β-catenin stability by promoting its acetylation via the acetyltransferases CREB-binding protein and P300/CREB-binding-protein-associated factor. Consequently, PLD6 ablation reduces cancer stem cell-associated gene expression downstream of Wnt/β-catenin signaling, suppressing stem-like traits and chemoresistance to 5-fluorouracil. Furthermore, PLD6 depletion attenuates CRC tumorigenesis in both subcutaneous and orthotopic tumor models. Overall, PLD6 acts as an oncogenic switch by promoting mitochondria-mediated retrograde signaling, thereby regulating Wnt signaling in CRC.
© 2025. The Author(s).

  • Biochemistry and Molecular biology
  • Cancer Research
  • Cell Biology
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