Aberrant Differentiation Research Articles

O13 JAK inhibitors to restore skin barrier function in ARCI

Abstract The autosomal recessive congenital ichthyoses (ARCI) are a group of chronic conditions where there is unmet therapeutic need. Harlequin ichthyosis (HI) is the most severe form of ARCI, with aberrant differentiation of the epidermis leading to a severe barrier defect. It is caused by mutations in ABCA12, a lipid transporter involved in the transport of glucosylceramides from the lamellar body to the lipid lamellae. Lamellar ichthyosis is caused by mutations in TGM1. Several Janus kinase (JAK) inhibitors (JAKi) inhibiting the JAK–STAT pathway are now licensed for atopic dermatitis. Previous work from our group in an in vitro HI model showed that tofacitinib had a restorative effect on the lipid barrier. We hypothesized that JAKi A, B and C could restore the epidermal barrier in both HI three-dimensional (3D) organotypic models (OTs) made using ABCA12 CrispR-Cas9 knockout and wild-type keratinocytes and ARCI 3D OTs generated with short hairpin RNA knock down of TGM1. The JAKi were tested at three concentrations in the 3D models (20, 50 and 500 nmol L–1 for JAKiA; 10, 50 and 250 nmol L–1 for JAKiB; 2, 25 and 125 nmol L–1 for JAKiC) and vehicle only was used as the control. The OTs were stained with haematoxylin and eosin, Nile red and differentiation markers such as K10, K14, transglutaminase 1 (TGM1) and involucrin. All three JAKi had a positive effect on the epidermal barrier. The epidermal structure looked more organized and uniform, with an increase in neutral and polar lipids in the upper epidermis. The differentiation markers showed normalization of the expression of involucrin, K10 and TGM1 at the same drug concentrations. These results suggest that JAKi have a generalized positive effect on the skin barrier and will be further investigated in an in vivo mouse model of HI.

The Role of Ladinin-1 in Cancer

Ladinin-1 (LAD1) is a protein originally called mammalian epidermal basement membrane collagen anchored silk protein. The molecular weight of the protein is 59 kD. It is a cytoskeleton related protein, responsible for maintaining the the coherence of dermal-epidermal junction, and it helps to connect epithelial cells with underlying mesenchymal cells. Biology of cancer includes aberrant cell differentiation and proliferation, unchecked growth, invasion, and metastasis, among other biological traits. LAD1 affects the migration, metastasis, proliferation and other important physiological processes of cells by regulating its expression, thus affecting the genesis and occurrence of cancer. However, the expression of LAD1 in different cancers has tumor specificity. This article reviews the biological functions of LAD1 in different cancers from breast cancer, colorectal cancer, NSCLC, and cervical cancer. It briefly summarizes the structure of LAD1 and further exploration of cancer-related treatment mechanisms can be provided by understanding its potential molecular mechanism of function in cancer cells LAD1 has potential value in anti-cancer treatment because of its important biological functions.

Orientin suppresses osteoclastogenesis and ameliorates ovariectomy-induced osteoporosis via suppressing ROS production.

The aberrant differentiation of osteoclasts is a key feature of the pathogenesis of osteoporosis, which has a devastating impact on human health. While the effects of Orientin (Ori) on osteoporosis, particularly on RANKL-stimulated osteoclast production and activation, remain still unclear, Ori has been found to display several biological activities, including antioxidant and anti-inflammatory. In this work, we investigated the possible pathways through which Ori suppressed RANKL-induced osteoclast development and showed for the first time that it does so. The macrophages from the bone marrow (BMMs) were cultivated and then treated with Ori after being stimulated with RANKL. Then, TRAP-positive multinucleated cells were counted, and F-actin ring analysis was used to assess Ori's impact on mature osteoclast development. In addition, dihydroethidium (DHE) staining was used to evaluate the impact of Ori on RANKL-induced reactive oxygen species (ROS). In addition, we performed western blotting and quantitative RT-PCR analysis to investigate probable causes of these downregulation effects. We discovered that Ori inhibits the creation of osteoclasts, the gene and protein expressions unique to osteoclasts, and the ROS production. By activating Nrf2 and other ROS-scavenging enzymes, Ori reduces intracellular ROS levels. The expression of the main transcription factor of osteoclast development, c-Fos, was downregulated together with NFATc1, CTSK, and NFATc2, thanks to Ori's inhibition of RANKL-induced NF-κB. Consistent with its in vitro antiosteoclastogenic action, Ori therapy in the ovariectomized (OVX) rat model was also able to restore bone mass and improve microarchitecture in the distal femurs. Together, our results demonstrate that Ori is a flavonoid molecule with therapeutic promise for bone illnesses associated with osteoclasts, such as osteoporosis.

Exosome-mediated small interfering RNA delivery inhibits aberrant osteoblast differentiation in Apert syndrome model mice

ObjectiveApert syndrome, an autosomal dominant congenital disorder characterized by craniosynostosis, is caused by a missense mutation (S252W or P253R) in fibroblast growth factor receptor 2 (FGFR2). Exosomes are naturally occurring carriers that deliver nucleic acids, including small interfering RNA (siRNA), to induce gene silencing. This study aimed to develop siRNA-loaded exosomes (Ex-siRNAFgfr2S252W) to silence the Fgfr2S252W gain-of-function mutation, thereby inhibiting the increased osteoblastic differentiation caused by the constitutive activation of FGFR2 signaling in calvarial osteoblastic cells isolated from Apert syndrome model mice. DesignPrimary calvarial osteoblast-like cells were isolated from the embryonic calvarial sutures of the Apert syndrome model (Fgfr2S252W/+) and littermate wild-type mice (Ap-Ob and Wt-Ob, respectively). Exosomes were extracted from the serum of wild-type mice, validated using biomarkers, and used to encapsulate siRNAs. After exosome-mediated siRNA transfection, cells were analyzed under a fluorescence microscope to validate the delivery of Ex-siRNAFgfr2S252W, followed by western blot and real-time reverse transcription polymerase chain reaction analyses. ResultsAfter 24 h of Ex-siRNAFgfr2S252W delivery in both Ap-Ob and Wt-Ob, siRNA-loaded exosome delivery was validated. Moreover, p44/42 mitogen-activated protein kinase (MAPK) phosphorylation, runt-related transcription factor 2 (Runx2), and collagen type 1 alpha 1 (Col1a1) mRNA expression, and alkaline phosphatase (ALP) activity were significantly increased in Ap-Ob. The levels of phospho-p44/42 protein, Runx2, Col1a1, and ALP were significantly decreased after Ex-siRNAFgfr2S252W transfection but did not affect Wt-Ob. ConclusionsThese results indicate that exosome-mediated delivery of siRNA targeting Fgfr2S252W is a potential non-invasive treatment for aberrant FGF/FGFR signaling.

Neutrophil and NETosis Modulation in Traumatic Heterotopic Ossification.

To characterize the role of neutrophil extracellular traps (NETs) in heterotopic ossification (HO) formation and progression and to use mechanical and pharmacological methods to decrease NETosis and mitigate HO formation. Traumatic HO is the aberrant osteochondral differentiation of mesenchymal progenitor cells after traumatic injury, burns, or surgery. While the innate immune response has been shown to be necessary for HO formation, the specific immune cell phenotype and function remain unknown. Neutrophils, one of the earliest immune cells to respond after HO-inducing injuries, can extrude DNA, forming highly inflammatory NETs. We hypothesized that neutrophils and NETs would be diagnostic biomarkers and therapeutic targets for the detection and mitigation of HO. C57BL6J mice underwent burn/tenotomy (a well-established mouse model of HO) or a non-HO-forming sham injury. These mice were either (1) ambulated ad libitum, (2) ambulated ad libitum with daily intraperitoneal hydroxychloroquine, ODN-2088 (both known to affect NETosis pathways), or control injections, or (3) had the injured hind limb immobilized. Single-cell analysis was performed to analyze neutrophils, NETosis, and downstream signaling after the HO-forming injury. Immunofluorescence microscopy was used to visualize NETosis at the HO site and neutrophils were identified using flow cytometry. Serum and cell lysates from HO sites were analyzed using enzyme-linked immunosorbent assay for myeloperoxidase-DNA and ELA2-DNA complexes to identify NETosis. Micro-computerized tomography was performed on all groups to analyze the HO volume. Molecular and transcriptional analyses revealed the presence of NETs within the HO injury site, which peaked in the early phases after injury. These NETs were highly restricted to the HO site, with gene signatures derived from both in vitro NET induction and clinical neutrophil characterizations showing a high degree of NET "priming" at the site of injury, but not in neutrophils in the blood or bone marrow. Cell-cell communication analyses revealed that this localized NET formation coincided with high levels of toll-like receptor signaling specific to neutrophils at the injury site. Reducing the overall neutrophil abundance within the injury site, either pharmacologically through treatment with hydroxychloroquine, the toll-like receptor 9 inhibitor OPN-2088, or mechanical treatment with limb offloading, results in the mitigation of HO formation. These data provide a further understanding of the ability of neutrophils to form NETs at the injury site, clarify the role of neutrophils in HO, and identify potential diagnostic and therapeutic targets for HO mitigation.

EPEN-12. COMPARING CELLULAR HIERARCHIES AND SPATIAL ARCHITECTURE ACROSS MOLECULAR SUBGROUPS OF SUPRATENTORIAL EPENDYMOMAS

Abstract Ependymomas (EPN) are among the most common and fatal pediatric brain tumors with currently no targeted therapies available. Molecular studies including genome-wide DNA methylation profiling have shown that supratentorial ependymoma is subdivided into subgroups characterized by distinct fusion proteins: ZFTA-RELA fusion-positive (ZFTA-RELA), YAP1 fusion-positive (ST-YAP1), and four alternative ZFTA fusion-positive (ZFTA-Cluster 1, ZFTA-Cluster 2, ZFTA-Cluster 3, and ZFTA-Cluster 4). ZFTA-RELA tumors have been identified as the most common and aggressive molecular group with high intra-tumoral heterogeneity. However, limited sample size and interpatient variability in previous studies highlight a critical need for comprehensive profiling of supratentorial ependymomas across a larger patient cohort. In particular, how ZFTA-RELA compares to other subgroups of supratentorial ependymoma is unknown. Here, we collected and profiled 44 supratentorial patient tumors encompassing ZFTA-RELA (n=21), ZFTA-Cluster 1 (n=6), ZFTA-Cluster 2 (n=4), ZFTA-Cluster 3 (n=7), ZFTA-Cluster 4 (n=2), and ST-YAP1 (n=4). We profiled all tumors by single cell/single nucleus RNA-sequencing, and further characterized ZFTA-RELA by single cell spatial transcriptomics. Within each patient’s tumor we find multiple normal and aberrant differentiation trajectories from neural progenitor-like cells towards glial-like, mesenchymal-like and ependymal-like cells. Using sequencing-based lineage tracing, we experimentally validate these computationally inferred cellular hierarchies in vitro. Notably, compared to ZFTA-RELA ependymomas we observed predominantly higher proportion of early neural progenitor-like cells in ZFTA-Cluster 2 and ZFTA-Cluster 3, while in ST-YAP1 greater representation of mature ependymal-like cells. These findings highlight differences in developmental and aberrant differentiation trajectories driven by combination of oncogenic fusions and cell of origin in supratentorial ependymoma subgroups. In addition, neural progenitor-like cells most highly express ZFTA-fusions and are spatially distinct from other cell states, highlighting oncogenic fusions driving tumorigenesis organized in spatial niches. Together, this study reveals previously unknown intra- and intertumoral heterogeneity across subgroups of supratentorial ependymoma, as well as distinct cellular and spatial architecture.

LncRNA MEG3 Promotes Osteogenic Differentiation of Tendon Stem Cells Via the miR-129-5p/TCF4/β-Catenin Axis and thus Contributes to Trauma-Induced Heterotopic Ossification.

Heterotopic ossification (HO) is one of the most intractable conditions following injury to the musculoskeletal system. In recent years, much attention has been paid to the role of lncRNA in musculoskeletal disorders, but its role in HO was still unclear. Therefore, this study attempted to determine the role of lncRNA MEG3 in the formation of post-traumatic HO and further explore the underlying mechanisms. On the basis of high-throughput sequencing and qPCR validation, elevated expression of the lncRNA MEG3 was shown during traumatic HO formation. Accordingly, in vitro experiments demonstrated that lncRNA MEG3 promoted aberrant osteogenic differentiation of tendon-derived stem cells (TDSCs). Mechanical exploration through RNA pulldown, luciferase reporter gene assay and RNA immunoprecipitation assay identified the direct binding relationship between miR-129-5p and MEG3, or miR-129-5p and TCF4. Further rescue experiments confirmed the miR-129-5p/TCF4/β-catenin axis to be downstream molecular cascade responsible for the osteogenic-motivating effects of MEG3 on the TDSCs. Finally, experiments in a mouse burn/tenotomy model corroborated the promoting effects of MEG3 on the formation of HO through the miR-129-5p/TCF4/β-catenin axis. Our study demonstrated that the lncRNA MEG3 promoted osteogenic differentiation of TDSCs and thus the formation of heterotopic ossification, which could be a potential therapeutic target.

Analysis of prognostic biomarker models and immune microenvironment in acute myeloid leukemia by integrative bioinformatics.

Acute myeloid leukemia (AML) is a hematological cancer driven on by aberrant myeloid precursor cell proliferation and differentiation. A prognostic model was created in this study to direct therapeutic care. Differentially expressed genes (DEGs) were investigated using the RNA-seq data from the TCGA-LAML and GTEx. Weighted Gene Coexpression Network Analysis (WGCNA) examines the genes involved in cancer. Find the intersection genes and construct the PPI network to discover hub genes and remove prognosis-related genes. A nomogram was produced for predicting the prognosis of AML patients using the risk prognosis model that was constructed using COX and Lasso regression analysis. GO, KEGG, and ssGSEA analysis were used to look into its biological function. TIDE score predicts immunotherapy response. Differentially expressed gene analysis revealed 1004 genes, WGCNA analysis revealed 19,575 tumor-related genes, and 941 intersection genes in total. Twelve prognostic genes were found using the PPI network and prognostic analysis. To build a risk rating model, RPS3A and PSMA2 were examined using COX and Lasso regression analysis. The risk score was used to divide the patients into two groups, and Kaplan-Meier analysis indicated that the two groups had different overall survival rates. Univariate and multivariate COX studies demonstrated that risk score is an independent prognostic factor. According to the TIDE study, the immunotherapy response was better in the low-risk group than in the high-risk group. We eventually selected out two molecules to construct prediction models that might be used as biomarkers for predicting AML immunotherapy and prognosis.

Mitotic bookmarking by SWI/SNF subunits.

For cells to initiate and sustain a differentiated state, it is necessary that a 'memory' of this state is transmitted through mitosis to the daughter cells1-3. Mammalian switch/sucrose non-fermentable (SWI/SNF) complexes (also known as Brg1/Brg-associated factors, or BAF) control cell identity by modulating chromatin architecture to regulate gene expression4-7, but whether they participate in cell fate memory is unclear. Here we provide evidence that subunits of SWI/SNF act as mitotic bookmarks to safeguard cell identity during cell division. The SWI/SNF core subunits SMARCE1 and SMARCB1 are displaced from enhancers but are bound to promoters during mitosis, and we show that this binding is required for appropriate reactivation of bound genes after mitotic exit. Ablation of SMARCE1 during a single mitosis in mouse embryonic stem cells is sufficient to disrupt gene expression, impair the occupancy of several established bookmarks at a subset of their targets and cause aberrant neural differentiation. Thus, SWI/SNF subunit SMARCE1 has a mitotic bookmarking role and is essential for heritable epigenetic fidelity during transcriptional reprogramming.

Genomic and Epigenetic Changes Drive Aberrant Skeletal Muscle Differentiation in Rhabdomyosarcoma

Rhabdomyosarcoma (RMS), the most common soft-tissue sarcoma in children and adolescents, represents an aberrant form of skeletal muscle differentiation. Both skeletal muscle development, as well as regeneration of adult skeletal muscle are governed by members of the myogenic family of regulatory transcription factors (MRFs), which are deployed in a highly controlled, multi-step, bidirectional process. Many aspects of this complex process are deregulated in RMS and contribute to tumorigenesis. Interconnected loops of super-enhancers, called core regulatory circuitries (CRCs), define aberrant muscle differentiation in RMS cells. The transcriptional regulation of MRF expression/activity takes a central role in the CRCs active in skeletal muscle and RMS. In PAX3::FOXO1 fusion-positive (PF+) RMS, CRCs maintain expression of the disease-driving fusion oncogene. Recent single-cell studies have revealed hierarchically organized subsets of cells within the RMS cell pool, which recapitulate developmental myogenesis and appear to drive malignancy. There is a large interest in exploiting the causes of aberrant muscle development in RMS to allow for terminal differentiation as a therapeutic strategy, for example, by interrupting MEK/ERK signaling or by interfering with the epigenetic machinery controlling CRCs. In this review, we provide an overview of the genetic and epigenetic framework of abnormal muscle differentiation in RMS, as it provides insights into fundamental mechanisms of RMS malignancy, its remarkable phenotypic diversity and, ultimately, opportunities for therapeutic intervention.

Cytokine signaling converging on IL11 in ILD fibroblasts provokes aberrant epithelial differentiation signatures.

Interstitial lung disease (ILD) is a heterogenous group of lung disorders where destruction and incomplete regeneration of the lung parenchyma often results in persistent architectural distortion of the pulmonary scaffold. Continuous mesenchyme-centered, disease-relevant signaling likely initiates and perpetuates the fibrotic remodeling process, specifically targeting the epithelial cell compartment, thereby destroying the gas exchange area. With the aim of identifying functional mediators of the lung mesenchymal-epithelial crosstalk with potential as new targets for therapeutic strategies, we developed a 3D organoid co-culture model based on human induced pluripotent stem cell-derived alveolar epithelial type 2 cells that form alveolar organoids in presence of lung fibroblasts from fibrotic-ILD patients, in our study referring to cases of pulmonary fibrosis, as well as control cell line (IMR-90). While organoid formation capacity and size was comparable in the presence of fibrotic-ILD or control lung fibroblasts, metabolic activity was significantly increased in fibrotic-ILD co-cultures. Alveolar organoids cultured with fibrotic-ILD fibroblasts further demonstrated reduced stem cell function as reflected by reduced Surfactant Protein C gene expression together with an aberrant basaloid-prone differentiation program indicated by elevated Cadherin 2, Bone Morphogenic Protein 4 and Vimentin transcription. To screen for key mediators of the misguided mesenchymal-to-epithelial crosstalk with a focus on disease-relevant inflammatory processes, we used mass spectrometry and characterized the secretome of end stage fibrotic-ILD lung fibroblasts in comparison to non-chronic lung disease (CLD) patient fibroblasts. Out of the over 2000 proteins detected by this experimental approach, 47 proteins were differentially abundant comparing fibrotic-ILD and non-CLD fibroblast secretome. The fibrotic-ILD secretome profile was dominated by chemokines, including CXCL1, CXCL3, and CXCL8, interfering with growth factor signaling orchestrated by Interleukin 11 (IL11), steering fibrogenic cell-cell communication, and proteins regulating extracellular matrix remodeling including epithelial-to-mesenchymal transition. When in turn treating alveolar organoids with IL11, we recapitulated the co-culture results obtained with primary fibrotic-ILD fibroblasts including changes in metabolic activity. We identified mediators likely contributing to the disease-perpetuating mesenchymal-to-epithelial crosstalk in ILD. In our alveolar organoid co-cultures, we were able to highlight the importance of fibroblast-initiated aberrant epithelial differentiation and confirmed IL11 as a key player in fibrotic-ILD pathogenesis by unbiased fibroblast secretome analysis.

Impaired expansion and selection of geminal center B cells in lupus drives autoantibody-producing cells

Abstract Lupus is a systemic autoimmune disease characterized by the presence of autoantibodies that form immune complexes in tissues leading to the recruitment of immune cells and subsequent inflammation and organ damage. The origin of autoantibody-secreting B cells is not clear, but the germinal center (GC) is of particular interest as the B cells here undergo somatic hypermutation, which may result in the generation of autoreactive memory or long-lived plasma cells. Within the GC, B cells cycle between two major zones: the dark zone (DZ) where mutation and proliferation occur, and the light zone (LZ) where affinity-based selection occurs. We found in lupus-prone mice that as autoantibodies increased, there was a reduction in proliferation measured by EdU incorporation in conjunction with dysregulation of the GC zones as B cells here became skewed towards a LZ phenotype (CXCR4 loCD86 +). As MYC expression in LZ B cells correlates with the strength of selection, we examined MYC levels by flow cytometry and Amnis and found it and its nuclearization decreased as disease progressed. Single cell BCR sequencing of GC B cells throughout the course of disease revealed a loss in BCR repertoire diversity and mutations. Furthermore, we found that despite the accumulation of LZ B cells, there was an increase in the generation of plasma cells and memory-like CD11c +Tbet +B cells, suggesting aberrant selection and differentiation into these potentially autoantibody-secreting cells. Thus, our findings suggest that as lupus disease progresses, the ability of GC B cells in the LZ to undergo proper selection is impaired, resulting the permissive selection of autoreactive B cells and differentiation into autoantibody-secreting cells. Supported by grants from the NIH/NIAMS (R01 AR073912, R01 AR073912 - 03W1)

An Integrated View of Stressors as Causative Agents in OA Pathogenesis.

Cells in the body are exposed to dynamic external and internal environments, many of which cause cell damage. The cell's response to this damage, broadly called the stress response, is meant to promote survival and repair or remove damage. However, not all damage can be repaired, and sometimes, even worse, the stress response can overtax the system itself, further aggravating homeostasis and leading to its loss. Aging phenotypes are considered a manifestation of accumulated cellular damage and defective repair. This is particularly apparent in the primary cell type of the articular joint, the articular chondrocytes. Articular chondrocytes are constantly facing the challenge of stressors, including mechanical overloading, oxidation, DNA damage, proteostatic stress, and metabolic imbalance. The consequence of the accumulation of stress on articular chondrocytes is aberrant mitogenesis and differentiation, defective extracellular matrix production and turnover, cellular senescence, and cell death. The most severe form of stress-induced chondrocyte dysfunction in the joints is osteoarthritis (OA). Here, we summarize studies on the cellular effects of stressors on articular chondrocytes and demonstrate that the molecular effectors of the stress pathways connect to amplify articular joint dysfunction and OA development.

The transcriptional co‐activator Yap1 promotes adult hippocampal neural stem cell activation

Most adult hippocampal neural stem cells (NSCs) remain quiescent, with only a minor portion undergoing active proliferation and neurogenesis. The molecular mechanisms that trigger the transition from quiescence to activation are still poorly understood. Here, we found the activity of the transcriptional co‐activator Yap1 to be enriched in active NSCs. Genetic deletion of Yap1 led to a significant reduction in the relative proportion of active NSCs, supporting a physiological role of Yap1 in regulating the transition from quiescence to activation. Overexpression of wild‐type Yap1 in adult NSCs did not induce NSC activation, suggesting tight upstream control mechanisms, but overexpression of a gain‐of‐function mutant (Yap1‐5SA) elicited cell cycle entry in NSCs and hilar astrocytes. Consistent with a role of Yap1 in NSC activation, single cell RNA sequencing revealed a partial induction of an activated NSC gene expression program. Furthermore, Yap1‐5SA expression also induced expression of Taz and other key components of the Yap/Taz regulon that were previously identified in glioblastoma stem cell‐like cells. Consequently, dysregulated Yap1 activity led to repression of hippocampal neurogenesis, aberrant cell differentiation, and partial acquisition of a glioblastoma stem cell‐like signature.

TWEAK Signaling-Induced ID1 Expression Drives Malignant Transformation of Hepatic Progenitor Cells During Hepatocarcinogenesis.

The malignant transformation of hepatic progenitor cells (HPCs) in the inflammatory microenvironment is the root cause of hepatocarcinogenesis. However, the potential molecular mechanisms are still elusive. The HPCs subgroup is identified by single-cell RNA (scRNA) sequencing and the phenotype of HPCs is investigated in the primary HCC model. Bulk RNA sequencing (RNA-seq) and proteomic analyses are also performed on HPC-derived organoids. It is found that tumors are formed from HPCs in peritumor tissue at the 16th week in a HCC model. Furthermore, it is confirmed that the macrophage-derived TWEAK/Fn14 promoted the expression of inhibitor of differentiation-1 (ID1) in HPCs via NF-κB signaling and a high level of ID1 induced aberrant differentiation of HPCs. Mechanistically, ID1 suppressed differentiation and promoted proliferation in HPCs through the inhibition of HNF4α and Rap1GAP transcriptions. Finally, scRNA sequencing of HCC patients and investigation of clinical specimens also verified that the expression of ID1 is correlated with aberrant differentiation of HPCs into cancer stem cells, patients with high levels of ID1 in HPCs showed a poorer prognosis. This study provides important intervention targets and a theoretical basis for the clinical diagnosis and treatment of HCC.

Principles, Processes and Modalities of Interaction Between Proto-Oncoprotein PIM-1 Kinase and Cell Division Cyclin CDC25A

All malignant tumors with aberrant cell differentiation and proliferation, unchecked growth, invasion, and metastasis are referred to as cancer. Its occurrence is a multi-step, complex process with many contributing components. Proto oncoprotein and The PIM kinase family is crucial to this procedure., and proto oncoprotein PIM-1 kinase is an important member of PIM family. The expression of proto oncoprotein PIM-1 is positively correlated with the status of lymphatic metastasis, and its overexpression could promote cell cycle and inhibit apoptosis. Cell division cycle 25 (CDC25) is a bispecific phosphatase from Schizosaccharomyces cerevisiae in 1986. CDC25 can activate CDK by catalyzing the dephosphorylation of inhibitory phosphorylation sites in the cell cycle dependent protein kinases (CDK) molecule, and regulate the response to DNA damage, thus promoting cell cycle operation. The interaction between the proto oncoprotein CDC25A in the above process is one of the keys to the current mechanism research with PIM-1 kinase. In this paper, PIM-1 and CDC25 are first introduced, respectively. Then, the interaction between PIM-1 and different substrates with a focus on CDC25A is presented. Finally, their role in tumor initiation and the application of CDC25A as a therapeutic target are highlighted. Therefore, this paper will discuss the interaction between CDC25A and PIM family.

Epigenetic regulation of stem cells in lung cancer oncogenesis and therapy resistance.

Epigenetics plays an important role in regulating stem cell signaling, as well as in the oncogenesis of lung cancer and therapeutic resistance. Determining how to employ these regulatory mechanisms to treat cancer is an intriguing medical challenge. Lung cancer is caused by signals that cause aberrant differentiation of stem cells or progenitor cells. The different pathological subtypes of lung cancer are determined by the cells of origin. Additionally, emerging studies have demonstrated that the occurrence of cancer treatment resistance is connected to the hijacking of normal stem cell capability by lung cancer stem cells, especially in the processes of drug transport, DNA damage repair, and niche protection. In this review, we summarize the principles of the epigenetic regulation of stem cell signaling in relation to the emergence of lung cancer and resistance to therapy. Furthermore, several investigations have shown that the tumor immune microenvironment in lung cancer affects these regulatory pathways. And ongoing experiments on epigenetics-related therapeutic strategies provide new insight for the treatment of lung cancer in the future.

239 The expression of RGR and correlation with proliferation and aberrant differentiation in cutaneous squamous cell carcinomas

239 The expression of RGR and correlation with proliferation and aberrant differentiation in cutaneous squamous cell carcinomas

Aberrant differentiation of second heart field mesoderm prefigures cellular defects in the outflow tract in response to loss of FGF8

Development of the outflow tract of the heart requires specification, proliferation and deployment of a progenitor cell population from the second heart field to generate the myocardium at the arterial pole of the heart. Disruption of these processes leads to lethal defects in rotation and septation of the outflow tract. We previously showed that Fibroblast Growth Factor 8 (FGF8) directs a signaling cascade in the second heart field that regulates critical aspects of OFT morphogenesis. Here we show that in addition to the survival and proliferation cues previously described, FGF8 provides instructive and patterning information to OFT myocardial cells and their progenitors that prevents their aberrant differentiation along a working myocardial program.

AHNAK, regulated by the OSM/OSMR signaling, involved in the development of primary localized cutaneous amyloidosis

BackgroundPrimary localized cutaneous amyloidosis (PLCA) is a chronic skin disease characterized by aberrant keratinocyte differentiation, epidermal hyperproliferation, and amyloid deposits. Previously, we demonstrated OSMR loss-function mutants enhanced basal keratinocyte differentiation through the OSMR/STAT5/KLF7 signaling in PLCA patients. ObjectiveTo investigate the underlying mechanisms involved in basal keratinocyte proliferation in PLCA patients that remain unclear. MethodsPatients with pathologically confirmed PLCA visiting the dermatologic outpatient clinic were involved in the study. Laser capture microdissection and mass spectrometry analysis, gene-edited mice, 3D human epidermis culture, flow cytometry, western blot, qRT-PCR and RNA sequencing were used to explore the underlying molecular mechanisms. ResultsIn this study, we found that AHNAK peptide fragments were enriched in the lesions of PLCA patients, as detected by laser capture microdissection and mass spectrometry analysis. The upregulated expression of AHNAK was further confirmed using immunohistochemical staining. qRT-PCR and flow cytometry revealed that pre-treatment with OSM can inhibit AHNAK expression in HaCaT cells, NHEKs, and 3D human skin models, but OSMR knockout or OSMR mutations abolished this down-regulation trend. Similar results were obtained in wild-type and OSMR knockout mice. More importantly, EdU incorporation and FACS assays demonstrated the knockdown of AHNAK could induce G1 phase cell cycle arrest and inhibit keratinocyte proliferation. Furthermore, RNA sequencing revealed that AHNAK knockdown regulated keratinocyte differentiation. ConclusionTaken together, these data indicated that the elevated expression of AHNAK by OSMR mutations led to hyperproliferation and overdifferentiation of keratinocytes, and the discovered mechanism might provide insights into potential therapeutic targets for PLCA.