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EMBO Reports Jun 2024Centrosomes are the canonical microtubule organizing centers (MTOCs) of most mammalian cells, including spermatocytes. Centrosomes comprise a centriole pair within a...
Centrosomes are the canonical microtubule organizing centers (MTOCs) of most mammalian cells, including spermatocytes. Centrosomes comprise a centriole pair within a structurally ordered and dynamic pericentriolar matrix (PCM). Unlike in mitosis, where centrioles duplicate once per cycle, centrioles undergo two rounds of duplication during spermatogenesis. The first duplication is during early meiotic prophase I, and the second is during interkinesis. Using mouse mutants and chemical inhibition, we have blocked centriole duplication during spermatogenesis and determined that non-centrosomal MTOCs (ncMTOCs) can mediate chromosome segregation. This mechanism is different from the acentriolar MTOCs that form bipolar spindles in oocytes, which require PCM components, including gamma-tubulin and CEP192. From an in-depth analysis, we identified six microtubule-associated proteins, TPX2, KIF11, NuMA, and CAMSAP1-3, that localized to the non-centrosomal MTOC. These factors contribute to a mechanism that ensures bipolar MTOC formation and chromosome segregation during spermatogenesis when centriole duplication fails. However, despite the successful completion of meiosis and round spermatid formation, centriole inheritance and PLK4 function are required for normal spermiogenesis and flagella assembly, which are critical to ensure fertility.
PubMed: 38943004
DOI: 10.1038/s44319-024-00187-6 -
Modern Pathology : An Official Journal... Jun 2024PLAG1 gene fusions were recently identified in a subset of uterine myxoid leiomyosarcomas (M-LMS). However, we have encountered cases of PLAG1-rearranged uterine...
PLAG1 gene fusions were recently identified in a subset of uterine myxoid leiomyosarcomas (M-LMS). However, we have encountered cases of PLAG1-rearranged uterine sarcomas (PLAG1-US) lacking M-LMS-like morphology and/or any expression of smooth muscle markers. To better characterize their clinicopathological features, we performed a multi-institutional search which yielded 11 cases. The patients ranged in age from 34-72 years (mean: 57). All tumors arose in the uterine corpus, ranging in size from 6.5-32 cm (mean: 15). The most common stage at presentation was pT1b (n=6), three cases had stage pT1 (unspecified) and one case each presented in stage pT2a and pT3b. Most were treated only by hysterectomy with adnexectomy. The follow-up (range: 7-71 months; median: 39 months) was available for 7 patients. Three cases (7-21 months of follow-up) had no evidence of disease. Three out of 4 remaining patients died of disease within 55-71 months, while the last developed peritoneal spread and was transferred for palliative care at 39 months. Morphologically, the tumors showed a high inter- and intratumoral heterogeneity. M-LMS-like and epithelioid LMS-like morphology was present in 3 and 5 primary tumors, respectively, the rest mostly presented as non-descript ovoid/spindle cell sarcomas. Unusual morphological findings included prominently hyalinized stroma (n=3), adipocytic differentiation with areas mimicking myxoid liposarcoma (n=2), osteosarcomatous differentiation (n=1) and undifferentiated pleomorphic sarcoma-like areas (n=1). The mitotic activity ranged from 3-24 mitoses/10 high-power fields (mean: 9), 3/10 cases showed necrosis. In 3/11 cases, no expression of SMA, h-caldesmon or desmin was noted, whereas 5/5 cases expressed PLAG1. By RNA-sequencing, the following fusion partners were identified: PUM1, CHCHD7 (each n=2), C15orf29, CD44, MYOCD, FRMD6, PTK2 and TRPS1 (each n=1). One case only showed PLAG1 gene break by FISH. Our study documents a much broader morphological spectrum of PLAG1-US than previously reported, encompassing but not limited to M-LMS-like morphology with occasional heterologous (particularly adipocytic) differentiation. Since it is currently difficult to precisely define their line of differentiation, for the time being, we suggest using a descriptive name PLAG1-rearranged uterine sarcoma.
PubMed: 38942115
DOI: 10.1016/j.modpat.2024.100552 -
Experimental and Therapeutic Medicine Aug 2024Mixed epithelial and stromal tumors (MESTs) of the kidney are rare renal neoplasms, primarily affecting middle-aged women. These tumors are characterized by a mix of...
Mixed epithelial and stromal tumors (MESTs) of the kidney are rare renal neoplasms, primarily affecting middle-aged women. These tumors are characterized by a mix of epithelial and stromal components. While generally benign, MESTs require accurate diagnosis and appropriate management due to the potential for malignant transformation. The present study reports the case of a 75-year-old male patient who underwent a partial nephrectomy following the incidental discovery of a kidney tumor. Histopathological examination revealed a partially cystic tumor with solid areas, measuring 26 mm in diameter. The tumor had cysts lined with cuboidal cells and an ovarian-like stroma. The solid component consisted of elongated cells with eosinophilic cytoplasm and oval nuclei, showing angiocentric growth around small blood vessels without nuclear atypia or mitoses. Since the morphology of the solid component could not reveal the differentiation of those cells, immunohistochemical staining was performed and a myopericytoma/myofibroma component was established, mostly based on the positivity of smooth muscle actin, muscle-specific actin, h-caldesmon, estrogen receptor, progesterone receptor, solute carrier family 2 facilitated glucose transporter member 1 and collagen IV, along with a lack of staining for desmin, CD34, CD31 and CD99. Thus, to the best of our knowledge, for the first time in the literature, MEST with myopericytoma/myofibroma stromal component in a male patient was reported.
PubMed: 38939172
DOI: 10.3892/etm.2024.12610 -
The Journal of Cell Biology Oct 2024Regulated cell shape change requires the induction of cortical cytoskeletal domains. Often, local changes to plasma membrane (PM) topography are involved. Centrosomes...
Regulated cell shape change requires the induction of cortical cytoskeletal domains. Often, local changes to plasma membrane (PM) topography are involved. Centrosomes organize cortical domains and can affect PM topography by locally pulling the PM inward. Are these centrosome effects coupled? At the syncytial Drosophila embryo cortex, centrosome-induced actin caps grow into dome-like compartments for mitoses. We found the nascent cap to be a collection of PM folds and tubules formed over the astral centrosomal MT array. The localized infoldings require centrosome and dynein activities, and myosin-based surface tension prevents them elsewhere. Centrosome-engaged PM infoldings become specifically enriched with an Arp2/3 induction pathway. Arp2/3 actin network growth between the infoldings counterbalances centrosomal pulling forces and disperses the folds for actin cap expansion. Abnormal domain topography with either centrosome or Arp2/3 disruption correlates with decreased exocytic vesicle association. Together, our data implicate centrosome-organized PM infoldings in coordinating Arp2/3 network growth and exocytosis for cortical domain assembly.
Topics: Animals; Actin-Related Protein 2-3 Complex; Actins; Cell Membrane; Centrosome; Drosophila melanogaster; Drosophila Proteins; Dyneins; Exocytosis; Microtubules
PubMed: 38935075
DOI: 10.1083/jcb.202403115 -
The American Journal of Surgical... Jun 2024The World Health Organization (WHO) diagnostic criteria for malignant phyllodes tumor (MPT) may miss a significant number of MPTs with metastatic potential. New refined...
The World Health Organization (WHO) diagnostic criteria for malignant phyllodes tumor (MPT) may miss a significant number of MPTs with metastatic potential. New refined diagnostic criteria (Refined Criteria) for MPT were recently proposed. The aim of this study is to validate the Refined Criteria. This validation study included 136 borderline (borderline phyllodes tumor [BoPT]) and MPT cases that were not included in the initial study. We evaluated tumor classifications based on both the Refined Criteria and the WHO criteria. The Refined Criteria defines MPT when these criteria are met (1) stromal overgrowth with ≥ 1 feature(s) of marked stromal cellularity, marked stromal cytologic atypia, or ≥10 mitoses per 10 high-power fields (10 mitoses/10 HPFs) or (2) marked stromal cellularity with ≥1 feature(s) of marked stromal cytologic atypia, ≥10 mitoses/10 HPFs or permeative border. The WHO criteria require all 5 morphologic features (stromal overgrowth, permeative border, marked stromal cellularity, marked stromal cytologic atypia, and ≥10 mitoses/10 HPFs) for an MPT diagnosis. Using the Refined Criteria, none of the 61 BoPTs developed metastasis and 40.0% of the 75 MPTs developed metastases; local recurrence was seen in 11.5% BoPTs and 25.3% MPTs. Using the WHO criteria, 9.6% of the 94 BoPTs developed metastases and 50.0% of the 42 MPTs developed metastases; 14.9% of the BoPTs had local recurrence and 28.6% of the MPTs had local recurrence. Nine (30.0%) of the 30 tumors that developed distant metastases were diagnosed as BoPTs by the WHO criteria. When we combined the 75 MPTs from this validation cohort with the 65 MPT cases from the published data using the Refined Criteria, 50 (35.7%) of the 140 MPTs developed metastases, whereas 8 cases with metastases were <5 cm. In the univariate analysis with log-rank test, stromal overgrowth, marked stromal cellularity, marked stromal cytologic atypia, ≥10 mitoses/10 HPFs, presence of heterologous components other than liposarcomatous component, and presence of stromal necrosis were significantly associated with the risk of metastasis (all with P < 0.05). In multivariate analysis with Cox proportional hazard regression, stromal overgrowth and marked stromal cellularity were significantly associated with metastasis (both with P < 0.001). The Refined Criteria are superior to the WHO criteria in predicting the clinical outcomes of BoPTs and MPTs. Using the Refined Criteria, 35.7% of 140 patients with MPT developed metastases, whereas none (0%) of the patients with BoPT developed metastases. Patients with MPT have a high metastatic rate; these patients may benefit from systemic chemotherapy or targeted therapies. In contrast, patients with BoPT may be managed with complete local excision alone without chemotherapy.
PubMed: 38934254
DOI: 10.1097/PAS.0000000000002264 -
Medicina (Kaunas, Lithuania) Jun 2024: This study aimed to elucidate the cytologic characteristics and diagnostic usefulness of endoscopic ultrasonography-fine needle aspiration cytology (EUS-FNAC) by... (Comparative Study)
Comparative Study
: This study aimed to elucidate the cytologic characteristics and diagnostic usefulness of endoscopic ultrasonography-fine needle aspiration cytology (EUS-FNAC) by comparing it with liquid-based preparation (LBP) and conventional smear (CS) in pancreas. : The diagnostic categories (I through VII) were classified according to the World Health Organization Reporting System for Pancreaticobiliary Cytopathology. Ten cytologic features, including nuclear and additional features, were evaluated in 53 cases subjected to EUS-FNAC. Nuclear features comprised irregular nuclear contours, nuclear enlargement, hypochromatic nuclei with parachromatin clearing, and nucleoli. Additional cellular features included isolated atypical cells, mucinous cytoplasm, drunken honeycomb architecture, mitosis, necrotic background, and cellularity. A decision tree analysis was conducted to assess diagnostic efficacy. : The diagnostic concordance rate between LBP and CS was 49.1% (26 out of 53 cases). No significant differences in nuclear features were observed between categories III (atypical), VI (suspicious for malignancy), and VII (malignant). The decision tree analysis of LBP indicated that cases with moderate or high cellularity and mitosis could be considered diagnostic for those exhibiting nuclear atypia. Furthermore, in CS, mitosis, isolated atypical cells, and necrotic background exerted a more significant impact on the diagnosis of EUS-FNAC. : Significant parameters for interpreting EUS-FNAC may differ between LBP and CS. While nuclear atypia did not influence the diagnosis of categories III, VI, and VII, other cytopathologic features, such as cellularity, mitosis, and necrotic background, may present challenges in diagnosing EUS-FNAC.
Topics: Humans; Endoscopic Ultrasound-Guided Fine Needle Aspiration; Male; Female; Middle Aged; Aged; Pancreas; Adult; Pancreatic Neoplasms; Cytodiagnosis; Aged, 80 and over; Cytology
PubMed: 38929547
DOI: 10.3390/medicina60060930 -
International Journal of Molecular... Jun 2024The study of the physiological and pathophysiological processes under extreme conditions facilitates a better understanding of the state of a healthy organism and can...
The study of the physiological and pathophysiological processes under extreme conditions facilitates a better understanding of the state of a healthy organism and can also shed light on the pathogenesis of diseases. In recent years, it has become evident that gravitational stress affects both the whole organism and individual cells. We have previously demonstrated that simulated microgravity inhibits proliferation, induces apoptosis, changes morphology, and alters the surface marker expression of megakaryoblast cell line MEG-01. In the present work, we investigate the expression of cell cycle cyclins in MEG-01 cells. We performed several experiments for 24 h, 72 h, 96 h and 168 h. Flow cytometry and Western blot analysis demonstrated that the main change in the levels of cyclins expression occurs under conditions of simulated microgravity after 96 h. Thus, the level of cyclin A expression showed an increase in the RPM group during the first 4 days, followed by a decrease, which, together with the peak of cyclin D, may indicate inhibition of the cell cycle in the G2 phase, before mitosis. In addition, based on the data obtained by PCR analysis, we were also able to see that both cyclin A and cyclin B expression showed a peak at 72 h, followed by a gradual decrease at 96 h. STED microscopy data also confirmed that the main change in cyclin expression of MEG-01 cells occurs at 96 h, under simulated microgravity conditions, compared to static control. These results suggested that the cell cycle disruption induced by RPM-simulated microgravity in MEG-01 cells may be associated with the altered expression of the main regulators of the cell cycle. Thus, these data implicate the development of cellular stress in MEG-01 cells, which may be important for proliferating human cells exposed to microgravity in real space.
Topics: Humans; Weightlessness Simulation; Cell Line; Cyclins; Cell Cycle; Megakaryocyte Progenitor Cells; Cyclin A; Cell Proliferation; Cyclin B
PubMed: 38928190
DOI: 10.3390/ijms25126484 -
International Journal of Molecular... Jun 2024Paclitaxel induces multipolar spindles at clinically relevant doses but does not substantially increase mitotic indices. Paclitaxel's anti-cancer effects are... (Review)
Review
Suppressing Anaphase-Promoting Complex/Cyclosome-Cell Division Cycle 20 Activity to Enhance the Effectiveness of Anti-Cancer Drugs That Induce Multipolar Mitotic Spindles.
Paclitaxel induces multipolar spindles at clinically relevant doses but does not substantially increase mitotic indices. Paclitaxel's anti-cancer effects are hypothesized to occur by promoting chromosome mis-segregation on multipolar spindles leading to apoptosis, necrosis and cyclic-GMP-AMP Synthase-Stimulator of Interferon Genes (cGAS-STING) pathway activation in daughter cells, leading to secretion of type I interferon (IFN) and immunogenic cell death. Eribulin and vinorelbine have also been reported to cause increases in multipolar spindles in cancer cells. Recently, suppression of Anaphase-Promoting Complex/Cyclosome-Cell Division Cycle 20 (APC/C-CDC20) activity using CRISPR/Cas9 mutagenesis has been reported to increase sensitivity to Kinesin Family 18a (KIF18a) inhibition, which functions to suppress multipolar mitotic spindles in cancer cells. We propose that a way to enhance the effectiveness of anti-cancer agents that increase multipolar spindles is by suppressing the APC/C-CDC20 to delay, but not block, anaphase entry. Delaying anaphase entry in genomically unstable cells may enhance multipolar spindle-induced cell death. In genomically stable healthy human cells, delayed anaphase entry may suppress the level of multipolar spindles induced by anti-cancer drugs and lower mitotic cytotoxicity. We outline specific combinations of molecules to investigate that may achieve the goal of enhancing the effectiveness of anti-cancer agents.
Topics: Humans; Anaphase-Promoting Complex-Cyclosome; Antineoplastic Agents; Spindle Apparatus; Cdc20 Proteins; Neoplasms; Mitosis
PubMed: 38928036
DOI: 10.3390/ijms25126329 -
Genes Jun 2024Grapevine varieties from "Douro Superior" (NE Portugal) experience high temperatures, solar radiation, and water deficit during the summer. This summer's stressful...
Grapevine varieties from "Douro Superior" (NE Portugal) experience high temperatures, solar radiation, and water deficit during the summer. This summer's stressful growing conditions induce nucleic acids, lipids, and protein oxidation, which cause cellular, physiological, molecular, and biochemical changes. Cell cycle anomalies, mitosis delay, or cell death may occur at the cellular level, leading to reduced plant productivity. However, the foliar application of kaolin (KL) can mitigate the impact of abiotic stress by decreasing leaf temperature and enhancing antioxidant defence. Hence, this study hypothesised that KL-treated grapevine plants growing in NE Portugal would reveal, under summer stressful growing conditions, higher progression and stability of the leaf mitotic cell cycle than the untreated (control) plants. KL was applied after veraison for two years. Leaves, sampled 3 and 5 weeks later, were cytogenetically, molecularly, and biochemically analysed. Globally, integrating these multidisciplinary data confirmed the decreased leaf temperature and enhanced antioxidant defence of the KL-treated plants, accompanied by an improved regularity and completion of the leaf cell cycle relative to the control plants. Nevertheless, the KL efficacy was significantly influenced by the sampling date and/or variety. In sum, the achieved results confirmed the hypothesis initially proposed.
Topics: Vitis; Plant Leaves; Kaolin; Seasons; Stress, Physiological; Cell Cycle; Antioxidants
PubMed: 38927683
DOI: 10.3390/genes15060747 -
The Journal of Pathology Jun 2024SMAD4 is a tumor suppressor mutated or silenced in multiple cancers, including oral cavity squamous cell carcinoma (OSCC). Human clinical samples and cell lines, mouse...
SMAD4 is a tumor suppressor mutated or silenced in multiple cancers, including oral cavity squamous cell carcinoma (OSCC). Human clinical samples and cell lines, mouse models and organoid culture were used to investigate the role that SMAD4 plays in progression from benign disease to invasive OSCC. Human OSCC lost detectable SMAD4 protein within tumor epithelium in 24% of cases, and this loss correlated with worse progression-free survival independent of other major clinical and pathological features. A mouse model engineered for Kras expression in the adult oral epithelium induced benign papillomas, however the combination of Kras with loss of epithelial Smad4 expression resulted in rapid development of invasive carcinoma with features of human OSCC. Examination of regulatory pathways in 3D organoid cultures of SMAD4+ and SMAD4- mouse tumors with Kras mutation found that either loss of SMAD4 or inhibition of TGFβ signaling upregulated the WNT pathway and altered the extracellular matrix. The gene signature of the mouse tumor organoids lacking SMAD4 was highly similar to the gene signature of human head and neck squamous cell carcinoma. In summary, this work has uncovered novel mechanisms by which SMAD4 acts as a tumor suppressor in OSCC. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
PubMed: 38922866
DOI: 10.1002/path.6318