Cellular Dedifferentiation Research Articles

Deciphering primary and acquired immunotherapy resistance with whole genome and transcriptome analysis (WGTA).

2602 Background: Most cancer patients (pts) do not respond to antiPD1/PDL1 immune checkpoint inhibitors (ICI) or experience only a temporary benefit. Comprehensive molecular profiling with WGTA could broaden our understanding of the mechanisms contributing to primary (Pr) and acquired resistance (Ar) to ICI and identify novel predictive biomarkers. Methods: The Princess Margaret investigator-initiated Immune Resistance Interrogation Study (NCT04243720) aims to comprehensively characterize ICI-resistant cancers (Genta et. al. ASCO 2021). Fresh tumor biopsies and blood samples were obtained from solid tumor pts at the time of PD on ICI-based treatment. DNA/RNA was extracted from tumor tissue and paired buffy coat and sequenced using an Illumina NovaSeq6000 system (2x150 paired reads for WG and 2X100 paired reads for WT). Copy number alterations (CNA), structural variants (SVs), mutation signatures and genes expression were assessed. Wald test in univariable and multivariable logistic regression model was used for comparison. Results: As of January 2023, 73 pts (45 Pr/28 Ar) were enrolled. WGTA was completed in 22 pts (14 Pr/8 Ar). Key pt characteristics included: median age 60.5 years (range 26-79); male 68%/female 32%; melanoma 50%, squamous cell cancer of the head and neck 36%, and other tumor types 14%. Forty-one percent of the pts were treated with PD-1/PD-L1 inhibitor monotherapy and 59% with PD-1/PD-L1 inhibitor combinations. There were no significant differences in median tumor mutation burden (TMB, coding; 2.8, range 0.6-30.5 for Pr vs 4.4, range 1.6-12.8 for Ar), median percent genome altered by CNA (43% Pr vs 65% Ar) or median number of SVs (144, range 9-775, for Pr vs 76, range 25-924, for Ar pts). After performing RNA sequencing we observed a significantly higher expression of the epithelial mesenchymal transition (EMT) hallmark gene-set from msigDB and of 3 previously reported ICI-resistance gene expression signatures in Pr vs Ar ( p≤0.05) in univariable analysis. The signatures included genes involved in the regulation of EMT, cellular de-differentiation and a cancer associated fibroblast (CAF) signature (IPRES signature, Hugo et al. Cell 2016; melanocytic plasticity signature [MPS], Pérez-Guijarro et al. Nat Med 2020; LRRC15 CAF signature, Dominguez et al. Cancer Discov. 2020). After adjusting for cancer type, the MPS signature was significantly associated with Pr vs Ar resistance in multivariable analysis ( p = 0.048). Conclusions: No significant differences between Ar and Pr were observed in genomic features including TMB, CNAs and number of SVs. Cancers primary resistant to ICI were characterized by a higher expression of EMT, cell de-differentiation and CAF related genes, detected with transcriptome analysis. Our findings might indicate these features as possible driver of early ICI progression. Analysis of additional samples is ongoing.

Inflammatory tumor microenvironment of thyroid cancer promotes cellular dedifferentiation and silencing of iodide-handling genes expression.

Due to dedifferentiation of tumor cells, manifested by a decreased expression of iodide-handling genes in thyrocytes, some thyroid carcinomas lose their capability for radioiodine concentration and gradually develop radioactive iodine (RAI) resistance. This work aimed to investigate the role of tumor microenvironment (TME) in the process of tumor cell dedifferentiation. Bioinformatic analyses and subsequent immunohistochemistry (IHC) and western blot assays were performed in papillary thyroid carcinoma (PTC) and matched normal tissue. ELISA was used to assess the secretion of cytokines under the stimulation of pharmacological endoplasmic reticulum (ER) stress inducer. Higher levels of pro-inflammatory cytokines, interleukin 6 (IL-6) and (C-X-C motif chemokine ligand 8 (CXCL8), were found in thyroid cancer tissues compared with matched normal tissues. ER stress, induced by stressful environmental stimuli, such as nutrient deprivation and hypoxia, occurred in thyroid tumors. Classic ER stress inducers, thapsigargin (Tg) and tunicamycin (Tm), promoted the expression of IL6 and CXCL8 in thyroid cancer cells at mRNA and protein levels. Of note, rIL-6 and rCXCL8 promoted the dedifferentiation of thyroid cancer cells or even non-transformed cells in an autocrine/paracrine manner, weakening radioiodine uptake ability of thyroid cancer cells. Intriguingly, sorafenib, a multiple kinase inhibitor (MKI), could potently suppress not only ER stress-induced but also basal expressions of IL-6 and CXCL8 in thyroid cancer cells. The inflammatory TME could regulate cell dedifferentiation, leading to loss of thyroid-specific gene expressions, through reciprocal interaction between thyroid tumor cells and follicular cells. Our study provides a new perspective on the mechanisms of how inflammatory TME affects DTC dedifferentiation.

Abstract 109: A Spatial Transcriptomic Approach to Understanding Coronary Atherosclerotic Plaque Stability

Introduction: Classically, vulnerable plaques at risk for acute coronary syndrome (ACS) have been defined by cellular architecture. However, contemporary imaging studies have shed light into new mechanisms of ACS (e.g., plaque erosion), challenging plaque rupture as the sole mechanism of disease. Furthermore, mechanisms within the vascular microenvironment that may modulate these disease phenotypes are poorly understood. Our objective was to examine differential programming of smooth muscle and macrophage cells amongst patients with stable and unstable plaques using spatial transcriptomics. Methods: Autopsy-derived coronary arteries were reviewed by an independent pathologist and segregated into stable (N=8) and unstable (defined by the presence of CD68+ cells and a large lipid core, N=8) plaques for spatial profiling. In combination with immunofluorescent histology, our approach enabled cell-specific, spatially resolved transcriptional profiling of plaques with mapping of cell populations via gene expression patterns. Results: We observed unique spatial and cell-specific transcriptional signatures for stable and unstable plaques including regional differences in the tunica intima and media. These regions differentially expressed pro-inflammatory (e.g., IFN-gamma, MHC Class II, pro-inflammatory cytokines) and pro-thrombotic signaling pathways. Cell-type-specific expression analysis using spatial deconvolution revealed heterogeneous CD68+ cell populations which shared gene signatures with endothelial, smooth muscle, and myeloid cells. Conclusion: Our results highlight cell-specific and regional pro-inflammatory and coagulation transcriptional changes within unstable coronary arterial plaques and supports the idea of cellular dedifferentiation and intra-plaque plasticity as a contributor to plaque instability. These findings may help to identify novel mediators of ACS and potential therapeutic targets.

BRAF-mediated brain tumors in adults and children: A review and the Australian and New Zealand experience.

The mitogen-activated protein kinase (MAPK) pathway signaling pathway is one of the most commonly mutated pathways in human cancers. In particular, BRAF alterations result in constitutive activation of the rapidly accelerating fibrosarcoma-extracellular signal-regulated kinase-MAPK significant pathway, leading to cellular proliferation, survival, and dedifferentiation. The role of BRAF mutations in oncogenesis and tumorigenesis has spurred the development of targeted agents, which have been successful in treating many adult cancers. Despite advances in other cancer types, the morbidity and survival outcomes of patients with glioma have remained relatively stagnant. Recently, there has been recognition that MAPK dysregulation is almost universally present in paediatric and adult gliomas. These findings, accompanying broad molecular characterization of gliomas, has aided prognostication and offered opportunities for clinical trials testing targeted agents. The use of targeted therapies in this disease represents a paradigm shift, although the biochemical complexities has resulted in unexpected challenges in the development of effective BRAF inhibitors. Despite these challenges, there are promising data to support the use of BRAF inhibitors alone and in combination with MEK inhibitors for patients with both low-grade and high-grade glioma across age groups. Safety and efficacy data demonstrate that many of the toxicities of these targeted agents are tolerable while offering objective responses. Newer clinical trials will examine the use of these therapies in the upfront setting. Appropriate duration of therapy and durability of response remains unclear in the glioma patient cohort. Longitudinal efficacy and toxicity data are needed. Furthermore, access to these medications remains challenging outside of clinical trials in Australia and New Zealand. Compassionate access is limited, and advocacy for mechanism of action-based drug approval is ongoing.

Mechanical strain treatment improves nuclear transfer reprogramming efficiency by enhancing chromatin accessibility.

Cellular mechanical properties are considered to be important factors affecting cell fate transitions, but the links between cellular mechanical properties and transition efficiency and chromatin structure remain elusive. Here, we predicted that mechanical strain treatment could induce signatures of cellular dedifferentiation and transdifferentiation, and we validated this prediction by showing that mechanical strain-treated mouse cumulus cells (CCs) exhibit significantly improved somatic cell nuclear transfer (SCNT) reprogramming efficiency. We found that the chromatin accessibility of CCs was globally increased by mechanical straintreatment and that this increase was partially mediated by the induction of the YAP-TEAD interaction. Moreover, using mechanical strain-treated CCs could prevent transcriptional dysregulation in SCNT embryos. Taken together, our study results demonstrated that modulating cell mechanical properties to regulate epigenetic status is a promising approach to facilitate cell fate transition.

Investigation of the clinical utility of adhesion molecules in the management of thyroid nodules

To better understand the relationship among cell adhesion molecules (CAM) and investigate the clinical diagnostic and prognostic application of ICAM-1 (ICAM1), LFA-1 (ITGAL), and L-selectin (SELL) proteins and mRNA corresponding expression in thyroid cancer. Gene expression was evaluated by RT–qPCR, and protein expression was evaluated by immunohistochemistry. We evaluated 275 patients (218 women, 57 men, 48.4 ± 14.5 years old), including 102 benign and 173 malignant nodules. The 143 papillary thyroid carcinoma (PTC) and 30 follicular thyroid carcinoma (FTC) patients were managed according to current guidelines and followed-up for 78.7 ± 54.2 months. Malignant and benign nodules differed concerning mRNA (p = 0.0027) and protein (p = 0.0020 for nuclear) expression of L-selectin and ICAM-1 (mRNA: p = 0.0001 and protein: p = 0.0014) and protein expression of LFA-1 (p = 0.0168), but not mRNA expression of LFA-1 (p = 0.2131). SELL expression was more intense in malignant tumors (p = 0.0027). ICAM1 (p = 0.0064) and ITGAL (p = 0.0244) mRNA expression was higher in tumors with lymphocyte infiltrate. ICAM-1 expression correlated with younger age at diagnosis (p = 0.0312) and smaller tumor size (p = 0.0443). Also, LFA-1 expression correlated with higher age at diagnosis (p = 0.0376) and was more intense at stage III and IV (p = 0.0077). In general, the protein expression of the 3 CAM decreased as the process of cellular dedifferentiation occurred. We suggest that the SELL and ICAM1 genes and L-selectin and LFA-1 protein expression may help confirm malignancy and assist in the histological characterization of follicular patterned lesions, but we were unable to correlate these CAMs with patient outcomes.

Dedifferentiated Ovarian Carcinoma with ARID1A and ARID1B Mutations: A Clinicopathological Report and Literature Review.

Dedifferentiated carcinoma of the female genital tract is a relatively recently recognized aggressive tumor affecting predominantly perimenopausal and postmenopausal women. In addition to having an undifferentiated component, dedifferentiated carcinoma includes a juxtaposed endometrioid adenocarcinoma, FIGO grade 1 or 2. Molecular characterization of these tumors has been a subject of discussion in multiple recent articles. We present a case of dedifferentiated carcinoma of the ovary in a 70-year-old female demonstrating concurrent inactivation of ARID1A and ARID1B. To the best of our knowledge, this is the second clinical report demonstrating dedifferentiated carcinoma of the ovary with concurrent inactivation of ARID1A and ARID1B. ARID1A and ARID1B inactivation seems to represent an alternate mechanism of switch/sucrose nonfermentable complex inactivation in the development of dedifferentiated carcinoma. Additional studies are warranted to precisely understand the molecular mechanism of cellular dedifferentiation in the dedifferentiated endometrial/ovarian carcinomas, thus guiding the development of targeted therapy.

Genetic and Chemical Controls of Sperm Fate and Spermatocyte Dedifferentiation via PUF-8 and MPK-1 in Caenorhabditis elegans.

Using the nematode C. elegans germline as a model system, we previously reported that PUF-8 (a PUF RNA-binding protein) and LIP-1 (a dual-specificity phosphatase) repress sperm fate at 20 °C and the dedifferentiation of spermatocytes into mitotic cells (termed "spermatocyte dedifferentiation") at 25 °C. Thus, double mutants lacking both PUF-8 and LIP-1 produce excess sperm at 20 °C, and their spermatocytes return to mitotically dividing cells via dedifferentiation at 25 °C, resulting in germline tumors. To gain insight into the molecular competence for spermatocyte dedifferentiation, we compared the germline phenotypes of three mutant strains that produce excess sperm-fem-3(q20gf), puf-8(q725); fem-3(q20gf), and puf-8(q725); lip-1(zh15). Spermatocyte dedifferentiation was not observed in fem-3(q20gf) mutants, but it was more severe in puf-8(q725); lip-1(zh15) than in puf-8(q725); fem-3(q20gf) mutants. These results suggest that MPK-1 (the C. elegans ERK1/2 MAPK ortholog) activation in the absence of PUF-8 is required to promote spermatocyte dedifferentiation. This idea was confirmed using Resveratrol (RSV), a potential activator of MPK-1 and ERK1/2 in C. elegans and human cells, respectively. Notably, spermatocyte dedifferentiation was significantly enhanced by RSV treatment in the absence of PUF-8, and its effect was blocked by mpk-1 RNAi. We, therefore, conclude that PUF-8 and MPK-1 are essential regulators for spermatocyte dedifferentiation and tumorigenesis. Since these regulators are broadly conserved, we suggest that similar regulatory circuitry may control cellular dedifferentiation and tumorigenesis in other organisms, including humans.

TISSUE CULTURE AND ITS APPLICATION IN MODERN AGRICULTURE

Tissue culture is a technique of growing plant cells, tissues and organs in an artificial prepared medium under aseptic conditions, which was invented by Gottlieb Haberlandt in 1902. Plant tissue culture is based on cellular totipotency, dedifferentiation, and redifferentiation. This paper overviews about procedures and applications of tissue culture by the analysis of numerous published studies. Compared to normal plant breeding methods, which take substantially longer, crops produced through tissue culture is developed through accurate and time-saving methods. It enables the recovery of embryos created by incompatible crosses, eliminates the phenomena of seed dormancy seen in plant species, and the life cycle of some species whose life cycles are relatively long are shorten. Even in situations where the species would typically have poor rates of multiplication, tissue culture enables the quick generation of a large number of plants. Also tissue culture required less space for multiplication of clones. An agriculturally valuable phenotype should come from the genetic diversity recovered from tissue culture regenerated plants. There are numerous issues arises in tissue culture. Researchers are having difficulty propagating plant tissues and acclimating in vitro produced plants in their natural habitat. However, greater understanding and study will lead to more widespread use of tissue culture.

The Growing Liberality Observed in Primary Animal and Plant Cultures is Common to the Social Amoeba.

Tissue culture environment liberates cells fromordinary laws of multi-cellular organisms. This liberation enables cells several behaviors, such as proliferation, dedifferentiation, acquisition of pluripotency, immortalization, and reprogramming. Recently, the quantitative value of cellular dedifferentiation and differentiation was defined as "liberality", which is measurable as Shannon entropy of numerical transcriptome data and Lempel-Zip complexity of nucleotide sequence transcriptome data. The increasing liberality induced by the culture environment had first been observed in animal cells and had reconfirmed in plant cells.The phenomena may be common across the kingdom, also in a social amoeba. We measured the liberality of the social amoeba which disaggregated from multicellular aggregates and transferred into a liquid medium.

DDDR-06. NEUROFIBROMATOSIS TUMOR SUPPRESSORS COOPERATIVELY DRIVE TUMOR DE-DIFFERENTIATION AND MEK INHIBITOR RESISTANCE IN PERIPHERAL NERVOUS SYSTEM TUMORS

Abstract Schwann cell derived tumors comprising schwannomas, neurofibromas, and malignant peripheral nerve sheath tumors (MPNSTs) are the most common cancers of the peripheral nervous system and often arise in patients with neurofibromatosis type-1 (NF-1) or type-2 (NF-2). NF-1 is caused by loss of NF1, a negative regulator of Ras signaling, and NF-2 is caused by loss of NF2, a pleiotropic tumor suppressor with numerous functions including inhibition of PAK signaling. However, whether functional interactions exist between the NF1 and NF2 tumor suppressors remain unclear. More broadly, there are currently no effective molecular therapies for patients with Schwann cell tumors beyond the MEK inhibitor selumetinib to treat neurofibromas in patients with NF-1. Here, we integrate DNA methylation profiling, whole exome sequencing, bulk and single-cell RNA sequencing, biochemistry, and pharmacology across human samples, cell lines, and mouse xenografts to identify cellular de-differentiation as a driver of malignant transformation and selumetinib resistance. Single nuclear RNA-sequencing of human neurofibromas (n = 3) or MPNSTs (n = 3) revealed a total of 13 cell types with increased proliferating, de-differentiated tumor cell populations in MPNST samples. Single cell RNA-sequencing of MPNST mouse xenografts revealed persistence of de-differentiated cell populations in selumetinib treated samples compared to vehicle control, suggesting cellular de-differentiation underlies treatment resistance. A genome-wide CRISPRi screen for mediators of selumetinib response in NF1 deficient neurofibroma cells revealed NF2 loss drives selumetinib resistance. Consistently, NF2 suppression in NF1 deficient neurofibroma cells caused Schwann cell de-differentiation and activation of PAK, a serine threonine kinase. Translationally, a small molecule PAK inhibitor in combination with selumetinib formed an effective therapy in mouse MPNST xenografts. In sum, we elucidate a paradigm of de-differentiation driving malignant transformation and treatment resistance in Schwann cell tumors, uncovering a functional link between the NF1 and NF2 tumor suppressors that sheds light on a novel therapeutic vulnerability.

On tumoural growth and treatment under cellular dedifferentiation

Differentiated cancer cells may regain stem cell characteristics; however, the effects of such a cellular dedifferentiation on tumoural growth and treatment are currently understudied. Thus, we here extend a mathematical model of cancer stem cell (CSC) driven tumour growth to also include dedifferentiation. We show that dedifferentiation increases the likelihood of tumorigenesis and the speed of tumoural growth, both modulated by the proliferative potential of the non-stem cancer cells (NSCCs). We demonstrate that dedifferentiation also may lead to treatment evasion, especially when a treatment solely targets CSCs. Conversely, targeting both CSCs and NSCCs in parallel is shown to be more robust to dedifferentiation. Despite dedifferentiation, perturbing CSC-related parameters continues to exert the largest relative effect on tumoural growth; however, we show the existence of synergies between specific CSC- and NSCC-directed treatments which cause superadditive reductions of tumoural growth. Overall, our study demonstrates various effects of dedifferentiation on growth and treatment of tumoural lesions, and we anticipate our results to be helpful in guiding future molecular and clinical research on limiting tumoural growth in vivo.

Sequential Accumulation of ‘Driver’ Pathway Mutations Induces the Upregulation of Hydrogen-Sulfide-Producing Enzymes in Human Colonic Epithelial Cell Organoids

Recently, a CRISPR-Cas9 genome-editing system was developed with introduced sequential ‘driver’ mutations in the WNT, MAPK, TGF-β, TP53 and PI3K pathways into organoids derived from normal human intestinal epithelial cells. Prior studies have demonstrated that isogenic organoids harboring mutations in the tumor suppressor genes APC, SMAD4 and TP53, as well as the oncogene KRAS, assumed more proliferative and invasive properties in vitro and in vivo. A separate body of studies implicates the role of various hydrogen sulfide (H2S)-producing enzymes in the pathogenesis of colon cancer. The current study was designed to determine if the sequential mutations in the above pathway affect the expression of various H2S producing enzymes. Western blotting was used to detect the expression of the H2S-producing enzymes cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST), as well as several key enzymes involved in H2S degradation such as thiosulfate sulfurtransferase/rhodanese (TST), ethylmalonic encephalopathy 1 protein/persulfide dioxygenase (ETHE1) and sulfide-quinone oxidoreductase (SQR). H2S levels were detected by live-cell imaging using a fluorescent H2S probe. Bioenergetic parameters were assessed by Extracellular Flux Analysis; markers of epithelial-mesenchymal transition (EMT) were assessed by Western blotting. The results show that the consecutive mutations produced gradual upregulations in CBS expression—in particular in its truncated (45 kDa) form—as well as in CSE and 3-MST expression. In more advanced organoids, when the upregulation of H2S-producing enzymes coincided with the downregulation of the H2S-degrading enzyme SQR, increased H2S generation was also detected. This effect coincided with the upregulation of cellular bioenergetics (mitochondrial respiration and/or glycolysis) and an upregulation of the Wnt/β-catenin pathway, a key effector of EMT. Thus sequential mutations in colon epithelial cells according to the Vogelstein sequence are associated with a gradual upregulation of multiple H2S generating pathways, which, in turn, translates into functional changes in cellular bioenergetics and dedifferentiation, producing more aggressive and more invasive colon cancer phenotypes.

Differential expression and methylation patterns of NFATC1, NADSYN1 and JAK3 gene in equine chondrocytes expanded in monolayer culture

Ex vivo expansion of chondrocytes in monolayer (ML) culture for therapeutic purposes is burdened with difficulties related to the loss of cartilaginous phenotype. Epigenetic mechanisms responsible for regulation of gene expression are believed to underlie chondrocyte dedifferentiation. We have inspected the relevance of DNA methylation alterations for passage-related differential expression of NFATC1 gene involved in hard connective tissue turnover and development, NADSYN1 influencing redox metabolism, and JAK3 - an important driver of inflammation. We have assessed relative amount of transcript abundance and performed DNA bisulfite sequencing of upstream located elements. It seems that anabolic-like effects of chondrogenic differentiation were observed in form of NFATC1 and NADSYN1 upregulation in chondrocytes at the earlier stages of passaging whereas JAK3 upregulation at the 11th passage was the sign of chondrocytes dedifferentiation. Summarizing the inversely correlated DNA methylation and expression patterns in NFATC1 and JAK3 locus might be relevant for cellular dedifferentiation during chondrocyte expansion in monolayer. Obtained results are supportive for further studies on the role of encoded proteins in regenerative biology of articular cartilage using in vitro expanded chondrocytes.

Recent advances in the molecular basis of chemotherapy resistance and potential application of epigenetic therapeutics in chemorefractory renal cell carcinoma.

Among various types of cancers, kidney cancer is unique with respect to a low frequency of mutations and a relatively higher level of chemotherapy resistance. Resistance to chemotherapy is a major challenge in kidney cancer treatment in the clinic. Tremendous progress has been made in identifying the molecular changes associated with chemotherapy resistance in RCC. However, the exact contribution of these molecular changes to the acquisition of chemotherapy resistance is not fully understood. In addition to genetic changes, epigenetic alterations have been shown to contribute to various pathways associated with chemotherapy resistance, such as increased cell proliferation and survival, regulation of drug influx and efflux transporters, increased DNA repair, loss of DNA-damage-dependent apoptotic potential, cellular dedifferentiation to cancer stem cell, and epithelial-mesenchymal transitions (EMT). Moreover, recent studies suggest that epigenetic aberrations that can be reversed by epigenetic therapeutics can potentially be targeted to restore chemosensitivity in chemorefractory kidney cancer. This review article highlights current knowledge of the role of genetic and epigenetic aberrations as well as the physiological and metabolic changes associated with chemotherapeutic resistance. Additionally, current approaches and future directions for overcoming chemotherapeutic resistance including the potential of epigenetic therapeutic in chemorefractory kidney cancer have also been discussed. This article is categorized under: Cancer > Genetics/Genomics/Epigenetics.

Effect of dedifferentiation on noise propagation in cellular hierarchy.

Many fast renewing tissues have a hierarchical structure. Tissue-specific stem cells are at the root of this cellular hierarchy, which give rive to a whole range of specialized cells via cellular differentiation. However, increasing evidence shows that the hierarchical structure can be broken due to cellular dedifferentiation in which cells at differentiated stages can revert to the stem cell stage. Dedifferentiation has significant impacts on many aspects of hierarchical tissues. Here we investigate the effect of dedifferentiation on noise propagation by developing a stochastic model composed of different cell types. The moment equationsare derived, via which we systematically investigate how the noise in the cell number is changed by dedifferentiation. Our results suggest that dedifferentiation have different effects on the noises in the numbers of stem cells and nonstem cells. Specifically, the noise in the number of stem cells is significantly reduced by increasing dedifferentiation probability. Due to the dual effect of dedifferentiation on nonstem cells, however, more complex changes could happen to the noise in the number of nonstem cells by increasing dedifferentiation probability. Furthermore, it is found that even though dedifferentiation could turn part of the noise propagation process into a noise-amplifying step, it is very unlikely to turn the entire process into a noise-amplifying cascade.

Complex cross-talk between EZH2 and miRNAs confers hallmark characteristics and shapes the tumor microenvironment.

Cancer epigenetic mechanisms support the acquisition of hallmark characteristics during oncogenesis. EZH2 - an important histone methyltransferase that writes histone H3 lysine 27 trimethylation marks - is known to be dysregulated in cancer cells. However, the interactions between EZH2 and miRNAs that form a complex network of cross-talk and reciprocal regulation that enable cancer cells to acquire hallmark characteristics have been relatively poorly appreciated. The specific functions of EZH2 appear to be regulated by a vast array of miRNAs, which direct EZH2 toward regulation over the development of specific hallmark characteristics. This review discusses recent advances in the understanding of EZH2, focusing on its collaboration with miRNAs to orchestrate oncogenesis. These epigenetic processes promote the evasion of apoptosis/cell cycle arrest, cellular dedifferentiation and the establishment of a tumor microenvironment that facilitates local cancer cell invasion, anti-cancer drug resistance and evasion of the immune response.

Autophagic State Confers Facultative Stem Cell Capacity in The Intestinal Epithelium

BackgroundThe intestinal epithelium is a highly proliferative tissue that undergoes complete turnover in 3 to 5 days. The presence of intestinal stem cells expressing the canonical Wnt target gene Lgr5, known as active intestinal stem cells (a‐ISCs), are responsible for generating daughter cells that differentiate into specialized epithelial cells to carryout various functions in the intestine. The proliferative nature of the intestinal epithelium renders it susceptible to DNA damage‐inducing injury, such as high‐dose irradiation and chemotherapy. Although a‐ISCs and early daughter cells are killed by these insults, a radio‐resistant population of facultative intestinal stem cells (f‐ISCs) can regenerate lost a‐ISCs to restore homeostasis following injury. The functional characteristics of f‐ISCs are becoming increasingly understood, however, whether any epithelial cell can act as an f‐ISC is less clear. One reason for this ambiguity is a heavy reliance on Cre‐driven reporter mouse models with low recombination efficiency. Our objective was to find a functional marker to identify f‐ISCs based on cellular state rather than gene expression. The autophagy pathway has been shown to protect against DNA damage and irradiation‐induced apoptosis in the intestinal epithelium. Furthermore, recent studies demonstrate a requirement for the autophagy pathway during cellular de‐differentiation in both gastric chief and pancreatic acinar cells following metaplasia‐inducing injury. Given that autophagy plays roles in both radio‐resistance and cellular plasticity, two integral features of f‐ISCs, we hypothesized that autophagic activity could serve to identify cells with f‐ISC capacity.Methods and ResultsUsing the autophagic vesicle tracer dye CytoID combined with fluorescence‐activated cell sorting, we demonstrate that intestinal epithelial cells with high levels of CytoID exhibit increased organoid‐formation efficiency (OFE) compared to CytoID ‘low’ cells. Single cell sequencing reveals that the CytoID high population is largely composed of secretory cells including Paneth, Goblet, Tuft, and Enteroendocrine cells, whereas the CytoID low population consisted mainly of a‐ISCs and absorptive Enterocytes. Using reporter mice and antibodies against cell surface receptors, we observe that CytoID can identify cells with high OFE within Enteroendocrine, Paneth, and Goblet cell lineages. Finally, we demonstrate that autophagy is required for the enhanced organoid‐formation observed in CytoID high cells by plating these cells in the presence of the lysosomal inhibitor Bafilomycin A1.ConclusionsOur new data support the notion that epithelial cells in a high autophagic state are biased to secretory lineages and that autophagy status functions as a lineage agnostic marker of f‐ISCs. Furthermore, our data suggests that autophagy is required for organoid formation in these lineages.

Atypical presentation of the World Health Organization Grade 1 meningioma: A case report

Meningiomas are the most common benign neoplasm of the brain whereas ectopic presentation, although reported, is rare. Among these ectopic tumors, there are a group of purely intraosseous meningiomas, which usually are diagnosed differentially from common primary osseous tumor such as fibrous dysplasia and osteoid osteoma. The World Health Organization (WHO) Grade 1 meningioma with an involvement of scalp, calvarial bone, dura, and brain seen rarely. This type of atypical presentation of the WHO Grade 1 meningioma rarely documented. The main theories to justify the unusual topography appear to be embryological remains of neuroectodermal tissue or cellular dedifferentiation. Surgical treatment seems the best curative option. Meningioma with bony involvement could be very aggressive tumor, need to prepare accordingly for surgery.

IL-6 coaxes cellular dedifferentiation as a pro-regenerative intermediate that contributes to pericardial ADSC-induced cardiac repair

BackgroundCellular dedifferentiation is a regenerative prerequisite that warrants cell cycle reentry and appropriate mitotic division during de novo formation of cardiomyocytes. In the light of our previous finding that expression of injury-responsive element, Wilms Tumor factor 1 (WT1), in pericardial adipose stromal cells (ADSC) conferred a compelling reparative activity with concomitant IL-6 upregulation, we then aim to unravel the mechanistic network that governs the process of regenerative dedifferentiation after ADSC-based therapy.Methods and resultsWT1-expressing ADSC (eGFP:WT1) were irreversibly labeled in transgenic mice (WT1-iCre/Gt(ROSA)26Sor-eGFP) primed with myocardial infarction. EGFP:WT1 cells were enzymatically isolated from the pericardial adipose tissue and cytometrically purified (ADSCgfp+). Bulk RNA-seq revealed upregulation of cardiac-related genes and trophic factors in ADSCgfp+ subset, of which IL-6 was most abundant as compared to non-WT1 ADSC (ADSCgfp−). Injection of ADSCgfp+ subset into the infarcted hearts yielded striking structural repair and functional improvement in comparison to ADSCgfp− subset. Notably, ADSCgfp+ injection triggered significant quantity of dedifferentiated cardiomyocytes recognized as round-sharp, marginalization of sarcomeric proteins, expression of molecular signature of non-myogenic genes (Vimentin, RunX1), and proliferative markers (Ki-67, Aurora B and pH3). In the cultured neonatal cardiomyocytes, spontaneous dedifferentiation was accelerated by adding tissue extracts from the ADSC-treated hearts, which was neutralized by IL-6 antibody. Genetical lack of IL-6 in ADSC dampened cardiac dedifferentiation and reparative activity.ConclusionsTaken collectively, our results revealed a previous unappreciated effect of IL-6 on cardiac dedifferentiation and regeneration. The finding, therefore, fulfills the promise of stem cell therapy and may represent an innovative strategy in the treatment of ischemic heart disease.