p53-dependent and independent expression of p21 during cell growth, differentiation, and DNA damage

Identification of Biomarkers and Mechanisms Associated with Apoptosis in Recurrent Pregnancy Loss

In this study, we employed bioinformatics techniques to identify genes associated with apoptosis in recurrent pregnancy loss (RPL). We retrieved the RPL expression profile datasets GSE165004 and GSE73025 from the Gene Expression Omnibus (GEO) database. We also obtained data from the Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathway of Apoptosis (hsa04210) to identify apoptosis-related genes. In addition, we performed Friends analysis to explore the interactions between differential apoptosis genes and other genes in the functional pathway. We identified six differentially expressed genes related to apoptosis, including CTSZ, BCL2, PIK3CD, KRAS, GADD45G, and CASP8, with GADD45G as the most gene. Functional fertility analysis revealed that differentially expressed genes primarily regulated protein stability, cell number homeostasis, myeloid cell homeostasis, hematopoietic progenitor cell differentiation, lytic vacuole and lysosome functions, vacuolar and lysosomal membranes, transmembrane transporter binding, protein domain-specific binding, G-protein beta-subunit binding, phospholipid binding, and were involved in pathways such as Rap1 signaling, regulation of actin cytoskeleton, and NOD-like receptor signaling. KRAS exhibited the highest mutation rate in RPL-related cancer CESC. There was also a positive correlation between differentially expressed genes and B cell memory, CD4 memory resting T cells, follicular helper T cells, naïve B cells, and resting dendritic cells. We identified six differentially expressed genes related to apoptosis in RPL, with GADD45G as the most important. NOD-like receptor signaling pathway and regulation of actin cytoskeleton could be therapeutic targets for RPL.

p53 dependence of senescence markers p21v1 and p21v2 in aging and acute injury

The senescence phenotype is heterogeneous, as observed by the context-dependent differential expression of senescence markers. Here, we provide evidence to demonstrate an inverse relationship in the expression pattern of the two murine variants of p21 (p21v1, and p21v2) in aging and hemorrhagic shock. While an upregulation of p21v1 was observed following hemorrhagic shock injury, p21v2 was upregulated in the aged mouse. We further show that the p21v1 response is, at least, partially independent of p53.

Predicting p53-dependent cell transitions from thermodynamic models

A cell's fate involves transitions among its various states, each defined by a distinct gene expression profile governed by the topology of gene regulatory networks, which are affected by 3D genome organization. Here, we develop thermodynamic models to determine the fate of a malignant cell as governed by the tumor suppressor p53 signaling network, taking into account long-range chromatin interactions in the mean-field approximation. The tumor suppressor p53 responds to stress by selectively triggering one of the potential transcription programs that influence many layers of cell signaling. These range from p53 phosphorylation to modulation of its DNA binding affinity, phase separation phenomena, and internal connectivity among cell fate genes. We use the minimum free energy of the system as a fundamental property of biological networks that influences the connection between the gene network topology and the state of the cell. We constructed models based on network topology and equilibrium thermodynamics. Our modeling shows that the binding of phosphorylated p53 to promoters of target genes can have properties of a first order phase transition. We apply our model to cancer cell lines ranging from breast cancer (MCF-7), colon cancer (HCT116), and leukemia (K562), with each one characterized by a specific network topology that determines the cell fate. Our results clarify the biological relevance of these mechanisms and suggest that they represent flexible network designs for switching between developmental decisions.

A new model and precious tool to study molecular mechanisms of macrophage aging

The accumulation of senescent cells, characterized by a senescence-associated secretory phenotype (SASP), contributes to chronic inflammation and age-related diseases (ARD). During aging, macrophages can adopt a senescent-like phenotype and an altered function, which promotes senescent cell accumulation. In the context of aging and ARD, controlling the resolution of the inflammatory response and preventing chronic inflammation, especially by targeting macrophages, must be a priority. Aging being a dynamic process, we developed a model of in vitro murine peritoneal macrophage aging. Our results show that macrophages cultured for 7 or 14 days exhibit a senescence-like phenotype: proliferation decrease, the levels of cyclin-dependent kinase inhibitors p16INK4A and p21CIP1 and of pro-inflammatory SASP components (MCP-1, IL-6, IL-1β, TNF-α, and MMP-9) increase, phagocytosis capacity decline and glycolytic activity is induced. In our model, chronic treatment with CB3, a thioredoxin-1 mimetic anti-inflammatory peptide, completely prevents p21CIP1 increase and enables day 14 macrophages to maintain proliferative activity.We describe a new model of macrophage aging with a senescence-like phenotype associated with inflammatory, metabolic and functional perturbations. This model is a valuable tool for characterizing macrophage aging mechanisms and developing innovative strategies with promising therapeutical purpose in limiting inflammaging and ARD.

Trophoblast fusion in fetal growth restriction is inhibited by CTGF in a cell-cycle-dependent manner

Fetal growth restriction (FGR) is a relatively common complication of pregnancy, and insufficient syncytialization in the placenta may play an important role in the pathogenesis of FGR. However, the mechanism of impaired formation of the syncytiotrophoblast layer in FGR patients requires further exploration. In the present study, we demonstrated that the level of syncytialization was decreased in FGR patient placentas, while the expression of connective tissue growth factor (CTGF) was significantly upregulated. CTGF was found to inhibit trophoblast fusion via regulating cell cycle progress of BeWo cells. Furthermore, we found that CTGF negatively regulates cell cycle arrest in a p21-dependent manner as overexpression of p21 could rescue the impaired syncytialization induced by CTGF-overexpression. Besides, we also identified that CTGF inhibits the expression of p21 through ITGB4/PI3K/AKT signaling pathway. Our study provided a new insight for elucidating the pathogenic mechanism of FGR and a novel idea for the clinical therapy of FGR.

Molecular mechanisms of the anticancer action of fustin isolated from Cotinus coggygria Scop. in MDA-MB-231 triple-negative breast cancer cell line

The aim of the present work was to investigate some of the molecular mechanisms and targets of the anticancer action of the bioflavonoid fustin isolated from the heartwood of Cotinus coggygria Scop. in the triple-negative breast cancer cell line MDA-MB-231. For this purpose, we applied fluorescence microscopy analysis to evaluate apoptosis, necrosis, and mitochondrial integrity, wound healing assay to study fustin antimigratory potential and quantitative reverse transcription-polymerase chain reaction to analyze the expression of genes associated with cell cycle control, programmed cell death, metastasis, and epigenetic alterations. A complex network-based bioinformatic analysis was also employed for protein-protein network construction, hub genes identification, and functional enrichment. The results revealed a significant induction of early and late apoptotic and necrotic events, a slight alteration of the mitochondria-related fluorescence, and marked antimotility effect after fustin treatment. Of 34 analyzed genes, seven fustin targets were identified, of which CDKN1A, ATM, and MYC were significantly enriched in pathways such as cell cycle, intrinsic apoptotic signaling pathway in response to DNA damage and generic transcription pathway. Our findings outline some molecular mechanisms of the anticancer action of fustin pointing it out as a potential oncotherapeutic agent and provide directions for future in vivo research.

Glucose-dependent insulinotropic polypeptide (GIP) alleviates ferroptosis in aging-induced brain damage through the Epac/Rap1 signaling pathway

Glucose-dependent insulinotropic polypeptide (GIP), a 42-aminoacid hormone, exerts multifaceted effects in physiology, most notably in metabolism, obesity, and inflammation. Its significance extends to neuroprotection, promoting neuronal proliferation, maintaining physiological homeostasis, and inhibiting cell death, all of which play a crucial role in the context of neurodegenerative diseases. Through intricate signaling pathways involving its cognate receptor (GIPR), a member of the G protein-coupled receptors, GIP maintains cellular homeostasis and regulates a defense system against ferroptosis, an essential process in aging. Our study, utilizing GIP-overexpressing mice and in vitro cell model, elucidates the pivotal role of GIP in preserving neuronal integrity and combating age-related damage, primarily through the Epac/Rap1 pathway. These findings shed light on the potential of GIP as a therapeutic target for the pathogenesis of ferroptosis in neurodegenerative diseases and aging. [BMB Reports 2024; 57(9): 417-423].

Cellular zinc status alters chromatin accessibility and binding of p53 to DNA

Zn2+ is an essential metal required by approximately 850 human transcription factors. How these proteins acquire their essential Zn2+ cofactor and whether they are sensitive to changes in the labile Zn2+ pool in cells remain open questions. Using ATAC-seq to profile regions of accessible chromatin coupled with transcription factor enrichment analysis, we examined how increases and decreases in the labile zinc pool affect chromatin accessibility and transcription factor enrichment. We found 685 transcription factor motifs were differentially enriched, corresponding to 507 unique transcription factors. The pattern of perturbation and the types of transcription factors were notably different at promoters versus intergenic regions, with zinc-finger transcription factors strongly enriched in intergenic regions in elevated Zn2+ To test whether ATAC-seq and transcription factor enrichment analysis predictions correlate with changes in transcription factor binding, we used ChIP-qPCR to profile six p53 binding sites. We found that for five of the six targets, p53 binding correlates with the local accessibility determined by ATAC-seq. These results demonstrate that changes in labile zinc alter chromatin accessibility and transcription factor binding to DNA.

Unlocking the secrets of aging: Epigenetic reader BRD4 as the target to combatting aging-related diseases

BACKGROUND

Aging, a complex and profound journey, leads us through a labyrinth of physiological and pathological transformations, rendering us increasingly susceptible to aging-related diseases. Emerging investigations have unveiled the function of bromodomain containing protein 4 (BRD4) in manipulating the aging process and driving the emergence and progression of aging-related diseases.

AIM OF REVIEW

This review aims to offer a comprehensive outline of BRD4's functions involved in the aging process, and potential mechanisms through which BRD4 governs the initiation and progression of various aging-related diseases.

KEY SCIENTIFIC CONCEPTS OF REVIEW

BRD4 has a fundamental role in regulating the cell cycle, apoptosis, cellular senescence, the senescence-associated secretory phenotype (SASP), senolysis, autophagy, and mitochondrial function, which are involved in the aging process. Several studies have indicated that BRD4 governs the initiation and progression of various aging-related diseases, including Alzheimer's disease, ischemic cerebrovascular diseases, hypertension, atherosclerosis, heart failure, aging-related pulmonary fibrosis, and intervertebral disc degeneration (IVDD). Thus, the evidence from this review supports that BRD4 could be a promising target for managing various aging-related diseases, while further investigation is warranted to gain a thorough understanding of BRD4's role in these diseases.

A non-canonical role for a small nucleolar RNA in ribosome biogenesis and senescence

Cellular senescence is an irreversible state of cell-cycle arrest induced by various stresses, including aberrant oncogene activation, telomere shortening, and DNA damage. Through a genome-wide screen, we discovered a conserved small nucleolar RNA (snoRNA), SNORA13, that is required for multiple forms of senescence in human cells and mice. Although SNORA13 guides the pseudouridylation of a conserved nucleotide in the ribosomal decoding center, loss of this snoRNA minimally impacts translation. Instead, we found that SNORA13 negatively regulates ribosome biogenesis. Senescence-inducing stress perturbs ribosome biogenesis, resulting in the accumulation of free ribosomal proteins (RPs) that trigger p53 activation. SNORA13 interacts directly with RPL23, decreasing its incorporation into maturing 60S subunits and, consequently, increasing the pool of free RPs, thereby promoting p53-mediated senescence. Thus, SNORA13 regulates ribosome biogenesis and the p53 pathway through a non-canonical mechanism distinct from its role in guiding RNA modification. These findings expand our understanding of snoRNA functions and their roles in cellular signaling.

Sustained ERK signaling promotes G2 cell cycle exit and primes cells for whole-genome duplication

Whole-genome duplication (WGD) is a frequent event in cancer evolution that fuels chromosomal instability. WGD can result from mitotic errors or endoreduplication, yet the molecular mechanisms that drive WGD remain unclear. Here, we use live single-cell analysis to characterize cell-cycle dynamics upon aberrant Ras-ERK signaling. We find that sustained ERK signaling in human cells leads to reactivation of the APC/C in G2, resulting in tetraploid G0-like cells that are primed for WGD. This process is independent of DNA damage or p53 but dependent on p21. Transcriptomics analysis and live-cell imaging showed that constitutive ERK activity promotes p21 expression, which is necessary and sufficient to inhibit CDK activity and which prematurely activates the anaphase-promoting complex (APC/C). Finally, either loss of p53 or reduced ERK signaling allowed for endoreduplication, completing a WGD event. Thus, sustained ERK signaling-induced G2 cell cycle exit represents an alternative path to WGD.

Epistatic interactions between NMD and TRP53 control progenitor cell maintenance and brain size

Mutations in human nonsense-mediated mRNA decay (NMD) factors are enriched in neurodevelopmental disorders. We show that deletion of key NMD factor Upf2 in mouse embryonic neural progenitor cells causes perinatal microcephaly but deletion in immature neurons does not, indicating NMD's critical roles in progenitors. Upf2 knockout (KO) prolongs the cell cycle of radial glia progenitor cells, promotes their transition into intermediate progenitors, and leads to reduced upper-layer neurons. CRISPRi screening identified Trp53 knockdown rescuing Upf2KO progenitors without globally reversing NMD inhibition, implying marginal contributions of most NMD targets to the cell cycle defect. Integrated functional genomics shows that NMD degrades selective TRP53 downstream targets, including Cdkn1a, which, without NMD suppression, slow the cell cycle. Trp53KO restores the progenitor cell pool and rescues the microcephaly of Upf2KO mice. Therefore, one physiological role of NMD in the developing brain is to degrade selective TRP53 targets to control progenitor cell cycle and brain size.

Endothelial deletion of p53 generates transitional endothelial cells and improves lung development during neonatal hyperoxia

Bronchopulmonary dysplasia (BPD), a prevalent and chronic lung disease affecting premature newborns, results in vascular rarefaction and alveolar simplification. Although the vasculature has been recognized as a main player in this disease, the recently found capillary heterogeneity and cellular dynamics of endothelial subpopulations in BPD remain unclear. Here, we show Cap2 cells are damaged during neonatal hyperoxic injury, leading to their replacement by Cap1 cells which, in turn, significantly decline. Single-cell RNA-seq identifies the activation of numerous p53 target genes in endothelial cells, including Cdkn1a (p21). While global deletion of p53 results in worsened vasculature, endothelial-specific deletion of p53 reverses the vascular phenotype and improves alveolar simplification during hyperoxia. This recovery is associated with the emergence of a transitional EC state, enriched for oxidative stress response genes and growth factors. These findings implicate the p53 pathway in EC type transition during injury-repair and highlights the endothelial contributions to BPD.

p53 promotes revival stem cells in the regenerating intestine after severe radiation injury

Ionizing radiation induces cell death in the gastrointestinal (GI) epithelium by activating p53. However, p53 also prevents animal lethality caused by radiation-induced acute GI syndrome. Through single-cell RNA-sequencing of the irradiated mouse small intestine, we find that p53 target genes are specifically enriched in regenerating epithelial cells that undergo fetal-like reversion, including revival stem cells (revSCs) that promote animal survival after severe damage of the GI tract. Accordingly, in mice with p53 deleted specifically in the GI epithelium, ionizing radiation fails to induce fetal-like revSCs. Using intestinal organoids, we show that transient p53 expression is required for the induction of revival stem cells and is controlled by an Mdm2-mediated negative feedback loop. Together, our findings reveal that p53 suppresses severe radiation-induced GI injury by promoting fetal-like reprogramming of irradiated intestinal epithelial cells.

Inhibition of p53-MDM2 binding reduces senescent cell abundance and improves the adaptive responses of skeletal muscle from aged mice

Skeletal muscle adaptation to external stimuli, such as regeneration following injury and hypertrophy in response to resistance exercise, are blunted with advanced age. The accumulation of senescent cells, along with defects in myogenic progenitor cell (MPC) proliferation, have been strongly linked as contributing factors to age-associated impairment in muscle adaptation. p53 plays an integral role in all these processes, as upregulation of p53 causes apoptosis in senescent cells and prevents mitotic catastrophe in MPCs from old mice. The goal of this study was to determine if a novel pharmaceutical agent (BI01), which functions by upregulating p53 through inhibition of binding to MDM2, the primary p53 regulatory protein, improves muscle regeneration and hypertrophy in old mice. BI01 effectively reduced the number of senescent cells in vitro but had no effect on MPC survival or proliferation at a comparable dose. Following repeated oral gavage with 2 mg/kg of BI01 (OS) or vehicle (OV), old mice (24 months) underwent unilateral BaCl2 injury in the tibialis anterior (TA) muscle, with PBS injections serving as controls. After 7 days, satellite cell number was higher in the TA of OS compared to OV mice, as was the expression of genes involved in ATP production. By 35 days, old mice treated with BI01 displayed reduced senescent cell burden, enhanced regeneration (higher muscle mass and fiber cross-sectional area) and restoration of muscle function relative to OV mice. To examine the impact of 2 mg/kg BI01 on muscle hypertrophy, the plantaris muscle was subjected to 28 days of mechanical overload (MOV) in OS and OV mice. In response to MOV, OS mice had larger plantaris muscles and muscle fibers than OV mice, particularly type 2b + x fibers, associated with reduced senescent cells. Together our data show that BI01 is an effective senolytic agent that may also augment muscle metabolism to enhance muscle regeneration and hypertrophy in old mice.

Pyrogallol promotes growth arrest by activating the p53-mediated up-regulation of p21 and p62/SQSTM1-dependent degradation of β-catenin in nonsmall cell lung cancer cells

Pyrogallol (1,2,3-trihydroxybenzene), a polyphenolic natural compound, has attracted considerable attention with regard to its potential anticancer activity. However, further study is needed to elucidate the underlying mechanism related to the antiNSCLC activity of pyrogallol and provide a comprehensive theoretical basis for better clinical utilization of pyrogallol. Our current study aims to investigate the effects and potential underlying mechanisms of pyrogallol on the inhibition of NSCLC growth. Our results showed that pyrogallol treatment induced cell cycle arrest at the G2/M phase and apoptosis in two different NSCLC cell lines. Mechanistically, we found that the induction of cell cycle arrest in NSCLC cells at the G2/M phase by pyrogallol was due to the upregulation of p21 in a p53-dependent manner. And blockade of p53 and p21 effectively abolished the cell cycle arrest at the G2/M phase. Meanwhile, p53 inhibition has been found to abrogate the pyrogallol-induced apoptosis of the two NSCLC cells. Moreover, we revealed that the inhibitory effects of pyrogallol on β-catenin signaling resulted from autophagy initiation depending on p53 activation, accompanied by an increase in p62/SQSTM1 expression, thus p62 subsequently interacting with ubiquitinated β-catenin and facilitating autophagic destruction of β-catenin. Furthermore, in vivo experiments demonstrated that pyrogallol exerted growth inhibition on NSCLC with low toxicity through the same molecular mechanism as observed in vitro. Our findings could contribute to the understanding of the mechanism by which pyrogallol negatively regulates NSCLC growth, which could be effective in treating NSCLC.

Dysregulation of cellular membrane homeostasis as a crucial modulator of cancer risk

Cellular membranes serve as an epicentre combining extracellular and cytosolic components with membranous effectors, which together support numerous fundamental cellular signalling pathways that mediate biological responses. To execute their functions, membrane proteins, lipids and carbohydrates arrange, in a highly coordinated manner, into well-defined assemblies displaying diverse biological and biophysical characteristics that modulate several signalling events. The loss of membrane homeostasis can trigger oncogenic signalling. More recently, it has been documented that select membrane active dietaries (MADs) can reshape biological membranes and subsequently decrease cancer risk. In this review, we emphasize the significance of membrane domain structure, organization and their signalling functionalities as well as how loss of membrane homeostasis can steer aberrant signalling. Moreover, we describe in detail the complexities associated with the examination of these membrane domains and their association with cancer. Finally, we summarize the current literature on MADs and their effects on cellular membranes, including various mechanisms of dietary chemoprevention/interception and the functional links between nutritional bioactives, membrane homeostasis and cancer biology.

Bleomycin-treated myoblasts undergo p21-associated cellular senescence and have severely impaired differentiation

As we age, the ability to regenerate and repair skeletal muscle damage declines, partially due to increasing dysfunction of muscle resident stem cells-satellite cells (SC). Recent evidence implicates cellular senescence, which is the irreversible arrest of proliferation, as a potentiator of SC impairment during aging. However, little is known about the role of senescence in SC, and there is a large discrepancy in senescence classification within skeletal muscle. The purpose of this study was to develop a model of senescence in skeletal muscle myoblasts and identify how common senescence-associated biomarkers respond. Low-passage C2C12 myoblasts were treated with bleomycin or vehicle and then evaluated for cytological and molecular senescence markers, proliferation status, cell cycle kinetics, and differentiation potential. Bleomycin treatment caused double-stranded DNA breaks, which upregulated p21 mRNA and protein, potentially through NF-κB and senescence-associated super enhancer (SASE) signaling (p < 0.01). Consequently, cell proliferation was abruptly halted due to G2/M-phase arrest (p < 0.01). Bleomycin-treated myoblasts displayed greater senescence-associated β-galactosidase staining (p < 0.01), which increased over several days. These myoblasts remained senescent following 6 days of differentiation and had significant impairments in myotube formation (p < 0.01). Furthermore, our results show that senescence can be maintained despite the lack of p16 gene expression in C2C12 myoblasts. In conclusion, bleomycin treatment provides a valid model of damage-induced senescence that was associated with elevated p21, reduced myoblast proliferation, and aberrant cell cycle kinetics, while confirming that a multi-marker approach is needed for the accurate classification of senescence within skeletal muscle.

Exploring the effects of topoisomerase II inhibitor XK469 on anthracycline cardiotoxicity and DNA damage

Anthracyclines, such as doxorubicin (adriamycin), daunorubicin, or epirubicin, rank among the most effective agents in classical anticancer chemotherapy. However, cardiotoxicity remains the main limitation of their clinical use. Topoisomerase IIβ has recently been identified as a plausible target of anthracyclines in cardiomyocytes. We examined the putative topoisomerase IIβ selective agent XK469 as a potential cardioprotective and designed several new analogs. In our experiments, XK469 inhibited both topoisomerase isoforms (α and β) and did not induce topoisomerase II covalent complexes in isolated cardiomyocytes and HL-60, but induced proteasomal degradation of topoisomerase II in these cell types. The cardioprotective potential of XK469 was studied on rat neonatal cardiomyocytes, where dexrazoxane (ICRF-187), the only clinically approved cardioprotective, was effective. Initially, XK469 prevented daunorubicin-induced toxicity and p53 phosphorylation in cardiomyocytes. However, it only partially prevented the phosphorylation of H2AX and did not affect DNA damage measured by Comet Assay. It also did not compromise the daunorubicin antiproliferative effect in HL-60 leukemic cells. When administered to rabbits to evaluate its cardioprotective potential in vivo, XK469 failed to prevent the daunorubicin-induced cardiac toxicity in either acute or chronic settings. In the following in vitro analysis, we found that prolonged and continuous exposure of rat neonatal cardiomyocytes to XK469 led to significant toxicity. In conclusion, this study provides important evidence on the effects of XK469 and its combination with daunorubicin in clinically relevant doses in cardiomyocytes. Despite its promising characteristics, long-term treatments and in vivo experiments have not confirmed its cardioprotective potential.

ATM-Mediated translocation of RanBPM regulates DNA damage response by stabilizing p21 in non-small cell lung cancer cells

PURPOSE

Platinum-based chemotherapy remains a standard-of-care for most patients with advanced non-small cell lung cancer (NSCLC). DNA damage response (DDR) induced by platinum or Etoposide activated a panel of cell cycle-regulatory proteins including p21 through p53 pathway. Previous studies have reported that RanBPM has been involved in various cellular processes such as DDR by interacting with multiple proteins. However, the underlying mechanism remains unclear.

METHODS

NSCLC tissue microarrays were used for assessing the expression of RanBPM by immunohistochemical staining. The roles of RanBPM in the DDR of NSCLC progression was examined in in vitro cell lines and in vivo animal models. The regulation of RanBPM on protein stability and ubiquitination levels were investigated by immunoblots and in vivo ubiquitylation assay.

RESULTS

The level of p21 or RanBPM is lower in NSCLC than non-malignant tissues and has a highly positive correlation. Mechanistically, RanBPM protein physically interacts with p21, and RanBPM deubiquitinates p21 by recruiting a deubiquitinase USP11 to maintain protein stability of p21. RanBPM silencing significantly decreased p21 protein level. Conversely, RanBPM overexpression led to the accumulation of endogenous p21 protein regardless of p53 status. Functionally, RanBPM regulates DDR in a p21-dependent manner. Furthermore, DNA damage significantly promoted the nuclear translocation of RanBPM protein through ATM signaling pathways.

CONCLUSION

RanBPM is a novel regulator of P21 protein stability, and plays a critical role in the regulation of DDR.

Chimeric TβRII-SE/Fc overexpression by a lentiviral vector exerts strong antitumoral activity on colorectal cancer-derived cell lines in vitro and on xenografts

The TGF signaling pathway is a key regulator of cancer progression. In this work, we report for the first time the antitumor activity of TβRII-SE/Fc, a novel peptibody whose targeting domain is comprised of the soluble endogenous isoform of the human TGF-β type II receptor (TβRII-SE). Overexpression of TβRIISE/Fc reduces in vitro cell proliferation and migration while inducing cell cycle arrest and apoptosis in human colorectal cancer-derived cell lines. Moreover, TβRII-SE/Fc overexpression reduces tumorigenicity in BALB/c nude athymic mice. Our results revealed that TRII-SE/Fc-expressing tumors were significantly reduced in size or were even incapable of developing. We also demonstrated that the novel peptibody has the ability to inhibit the canonical TGF-β and BMP signaling pathways while identifying SMAD-dependent and independent proteins involved in tumor progression that are modulated by TβRII-SE/Fc. These findings provide insights into the underlying mechanism responsible for the antitumor activity of TβRII-SE/Fc. Although more studies are required to demonstrate the effectiveness and safety of the novel peptibody as a new therapeutic for the treatment of cancer, our initial in vitro and in vivo results in human colorectal tumor-derived cell lines are highly encouraging. Our results may serve as the foundation for further research and development of a novel biopharmaceutical for oncology.

Design and Synthesis of New bis-oxindole and Spiro(triazole-oxindole) as CDK4 Inhibitors with Potent Anti-breast Cancer Activity

BACKGROUND

Since CDKs have been demonstrated to be overexpressed in a wide spectrum of human malignancies, their inhibition has been cited as an effective technique for anticancer drug development.

METHODS

In this context, new bis-oxindole/spiro-triazole-oxindole anti-breast cancer drugs with potential CDK4 inhibitory effects were produced in this work. The novel series of bis-oxindole/spirotriazole- oxindole were synthesized from the reaction of bis-oxindole with the aniline derivatives then followed by 1,3-dipolar cycloaddition of hydrazonoyl chloride.

RESULTS

The structure of these bis-oxindole/spiro-triazole-oxindole series was proven based on their spectral analyses. Most bis-oxindole and bis-spiro-triazole-oxindole compounds effectively inhibited the growth of MCF-7 (IC50 = 2.81-17.61 μM) and MDA-MB-231 (IC50 = 3.23-7.98 μM) breast cancer cell lines with low inhibitory activity against normal WI-38 cells. While the reference doxorubicin showed IC50 values of 7.43 μM against MCF-7 and 5.71 μM against the MDA-MB-231 cell line. Additionally, compounds 3b, 3c, 6b, and 6d revealed significant anti-CDK4 activity (IC50 = 0.157- 0.618 μM) compared to palbociclib (IC50 = 0.071 μM). Subsequent mechanistic investigations demonstrated that 3c was able to trigger tumor cell death through the induction of apoptosis. Moreover, it stimulated cancer cell cycle arrest in the G1 phase. Furthermore, western blotting disclosed that the 3c-induced cell cycle arrest may be mediated through p21 upregulation.

CONCLUSION

According to all of the findings, bis-oxindole 3c shows promise as a cancer treatment targeting CDK4.

The chemotherapeutic agent doxorubicin induces brain senescence, with modulation by APOE genotype

Many cancer patients experience serious cognitive problems related to their treatment, which can greatly affect their quality of life. The molecular mechanisms of this cancer chemotherapy-induced cognitive impairment (CICI) are unknown, thus slowing the development of preventative approaches. We hypothesized that cancer chemotherapies could induce cellular senescence in the brain, creating a pro-inflammatory environment and damaging normal brain communication. We tested this hypothesis using the common chemotherapeutic agent doxorubicin in two independent mouse models. In the first model, we used mice that express tdTomato under the pdkn2a (p16) promoter; p16 is a regulator of cellular senescence, and its upregulation is denoted by the presence of fluorescently tagged cells. Two weeks after exposure to three doses of 5 mg/kg doxorubicin, the number of tdTomato positive cells were increased nearly three-fold in both the cerebral cortex and the hippocampus. tdTomato staining co-localized with neurons, microglia, oligodendrocyte precursor cells, and endothelial cells, but not astrocytes. In the second model, we used APOE knock-in mice, since the APOE4 allele is a risk factor for CICI in humans and mouse models. We isolated RNA from the cerebral cortex of APOE3 and APOE4 mice from one to 21 days after a single dose of 10 mg/kg doxorubicin. Using NanoString analysis of over 700 genes related to neuroinflammation and RT-qPCR analysis of cerebral cortex transcripts, we found two-fold induction of four senescence-related genes at three weeks in the APOE4 mice compared to the APOE3 control mice: p21(cdkn1a), p16, Gadd45a, and Egr1. We conclude that doxorubicin promotes cellular senescence pathways in the brain, supporting the hypothesis that drugs to eliminate senescent cells could be useful in preventing CICI.

An untapped window of opportunity for glioma: targeting therapy-induced senescence prior to recurrence

High-grade gliomas are primary brain tumors that are incredibly refractory long-term to surgery and chemoradiation, with no proven durable salvage therapies for patients that have failed conventional treatments. Post-treatment, the latent glioma and its microenvironment are characterized by a senescent-like state of mitotic arrest and a senescence-associated secretory phenotype (SASP) induced by prior chemoradiation. Although senescence was once thought to be irreversible, recent evidence has demonstrated that cells may escape this state and re-enter the cell cycle, contributing to tumor recurrence. Moreover, senescent tumor cells could spur the growth of their non-senescent counterparts, thereby accelerating recurrence. In this review, we highlight emerging evidence supporting the use of senolytic agents to ablate latent, senescent-like cells that could contribute to tumor recurrence. We also discuss how senescent cell clearance can decrease the SASP within the tumor microenvironment thereby reducing tumor aggressiveness at recurrence. Finally, senolytics could improve the long-term sequelae of prior therapy on cognition and bone marrow function. We critically review the senolytic drugs currently under preclinical and clinical investigation and the potential challenges that may be associated with deploying senolytics against latent glioma. In conclusion, senescence in glioma and the microenvironment are critical and potential targets for delaying or preventing tumor recurrence and improving patient functional outcomes through senotherapeutics.

Cellular zinc status alters chromatin accessibility and binding of transcription factor p53 to genomic sites

Zinc (Zn2+) is an essential metal required by approximately 2500 proteins. Nearly half of these proteins act on DNA, including > 850 human transcription factors, polymerases, DNA damage response factors, and proteins involved in chromatin architecture. How these proteins acquire their essential Zn2+ cofactor and whether they are sensitive to changes in the labile Zn2+ pool in cells remain open questions. Here, we examine how changes in the labile Zn2+ pool affect chromatin accessibility and transcription factor binding to DNA. We observed both increases and decreases in accessibility in different chromatin regions via ATAC-seq upon treating MCF10A cells with elevated Zn2+ or the Zn2+-specific chelator tris(2-pyridylmethyl)amine (TPA). Transcription factor enrichment analysis was used to correlate changes in chromatin accessibility with transcription factor motifs, revealing 477 transcription factor motifs that were differentially enriched upon Zn2+ perturbation. 186 of these transcription factor motifs were enriched in Zn2+ and depleted in TPA, and the majority correspond to Zn2+ finger transcription factors. We selected TP53 as a candidate to examine how changes in motif enrichment correlate with changes in transcription factor occupancy by ChIP-qPCR. Using publicly available ChIP-seq and nascent transcription datasets, we narrowed the 50,000+ ATAC-seq peaks to 2164 TP53 targets and subsequently selected 6 high-probability TP53 binding sites for testing. ChIP-qPCR revealed that for 5 of the 6 targets, TP53 binding correlates with the local accessibility determined by ATAC-seq. These results demonstrate that changes in labile zinc directly alter chromatin accessibility and transcription factor binding to DNA.

Ellagic Acid and Cancer Hallmarks: Insights from Experimental Evidence

Cancer is a complex and multifaceted disease with a high global incidence and mortality rate. Although cancer therapy has evolved significantly over the years, numerous challenges persist on the path to effectively combating this multifaceted disease. Natural compounds derived from plants, fungi, or marine organisms have garnered considerable attention as potential therapeutic agents in the field of cancer research. Ellagic acid (EA), a natural polyphenolic compound found in various fruits and nuts, has emerged as a potential cancer prevention and treatment agent. This review summarizes the experimental evidence supporting the role of EA in targeting key hallmarks of cancer, including proliferation, angiogenesis, apoptosis evasion, immune evasion, inflammation, genomic instability, and more. We discuss the molecular mechanisms by which EA modulates signaling pathways and molecular targets involved in these cancer hallmarks, based on in vitro and in vivo studies. The multifaceted actions of EA make it a promising candidate for cancer prevention and therapy. Understanding its impact on cancer biology can pave the way for developing novel strategies to combat this complex disease.

Zinc Oxide Nanoparticles (ZnO-NPs) Induce Cytotoxicity in the Zebrafish Olfactory Organs via Activating Oxidative Stress and Apoptosis at the Ultrastructure and Genetic Levels

Nanotechnology has gained tremendous attention because of its crucial characteristics and wide biomedical applications. Although zinc oxide nanoparticles (ZnO-NPs) are involved in many industrial applications, researchers pay more attention to their toxic effects on living organisms. Since the olfactory epithelium is exposed to the external environment, it is considered the first organ affected by ZnO-NPs. Herein, we demonstrated the cytotoxic effect of ZnO-NPs on the olfactory organ of adult zebrafish after 60 days post-treatment. We opted for this period when fishes stop eating their diet from the aquarium, appear feeble, and cannot swim freely. Our study demonstrated that ZnO-NPs induced significant malformations of the olfactory rosettes at histological, ultrastructural, and genetic levels. At the ultrastructure level, the olfactory lamellae appeared collapsed, malformed, and twisted with signs of degeneration and loss of intercellular connections. In addition, ZnO-NPs harmed sensory receptor and ciliated cells, microvilli, rodlet, crypt, and Kappe cells, with hyper-activity of mucous secretion from goblet cells. At the genetic level, ZnO-NPs could activate the reactive oxygen species (ROS) synthesis expected by the down-regulation of mRNA expression for the antioxidant-related genes and up-regulation of DNA damage, cell growth arrest, and apoptosis. Interestingly, ZnO-NPs affected the odor sensation at 60 days post-treatment (60-dpt) more than at 30-dpt, severely damaging the olfactory epithelium and irreparably affecting the cellular repairing mechanisms. This induced a dramatically adverse effect on the cellular endoplasmic reticulum (ER), revealed by higher CHOP protein expression, that suppresses the antioxidant effect of Nrf2 and is followed by the induction of apoptosis via the up-regulation of Bax expression and down-regulation of Bcl-2 protein.

Triple Reporter Assay: A Non-Overlapping Luciferase Assay for the Measurement of Complex Macromolecular Regulation in Cancer Cells Using a New Mushroom Luciferase-Luciferin Pair

This study demonstrates the development of a humanized luciferase imaging reporter based on a recently discovered mushroom luciferase (Luz) from Neonothopanus nambi. In vitro and in vivo assessments showed that human-codon-optimized Luz (hLuz) has significantly higher activity than native Luz in various cancer cell types. The potential of hLuz in non-invasive bioluminescence imaging was demonstrated by human tumor xenografts subcutaneously and by the orthotopic lungs xenograft in immunocompromised mice. Luz enzyme or its unique 3OH-hispidin substrate was found to be non-cross-reacting with commonly used luciferase reporters such as Firefly (FLuc2), Renilla (RLuc), or nano-luciferase (NLuc). Based on this feature, a non-overlapping, multiplex luciferase assay using hLuz was envisioned to surpass the limitation of dual reporter assay. Multiplex reporter functionality was demonstrated by designing a new sensor construct to measure the NF-κB transcriptional activity using hLuz and utilized in conjunction with two available constructs, p53-NLuc and PIK3CA promoter-FLuc2. By expressing these constructs in the A2780 cell line, we unveiled a complex macromolecular regulation of high relevance in ovarian cancer. The assays performed elucidated the direct regulatory action of p53 or NF-κB on the PIK3CA promoter. However, only the multiplexed assessment revealed further complexities as stabilized p53 expression attenuates NF-κB transcriptional activity and thereby indirectly influences its regulation on the PIK3CA gene. Thus, this study suggests the importance of live cell multiplexed measurement of gene regulatory function using more than two luciferases to address more realistic situations in disease biology.

The intensities of canonical senescence biomarkers integrate the duration of cell-cycle withdrawal

Senescence, a state of irreversible cell-cycle withdrawal, is difficult to distinguish from quiescence, a state of reversible cell-cycle withdrawal. This difficulty arises because quiescent and senescent cells are defined by overlapping biomarkers, raising the question of whether these states are truly distinct. To address this, we use single-cell time-lapse imaging to distinguish slow-cycling cells that spend long periods in quiescence from cells that never cycle after recovery from senescence-inducing treatments, followed by staining for various senescence biomarkers. We find that the staining intensity of multiple senescence biomarkers is graded rather than binary and reflects the duration of cell-cycle withdrawal, rather than senescence per se. Together, our data show that quiescent and apparent senescent cells are nearly molecularly indistinguishable from each other at a snapshot in time. This suggests that cell-cycle withdrawal itself is graded rather than binary, where the intensities of senescence biomarkers integrate the duration of past cell-cycle withdrawal.

IL-8 concurrently promotes idiopathic pulmonary fibrosis mesenchymal progenitor cell senescence and PD-L1 expression enabling escape from immune cell surveillance

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease. We discovered fibrogenic mesenchymal progenitor cells (MPCs) in the lungs of IPF patients that display cell-autonomous fibrogenicity and drive fibrotic progression. In a study of the IPF MPC nuclear proteome, we identified DNA damage as one of the most altered functions in IPF MPCs. In prior work we found that IL-8 drives IPF MPC self-renewal. IL-8 can promote replicative stress and DNA damage and induce senescence through the CXCR2 receptor. We hypothesized that IL-8 promotes DNA damage-mediated senescence in IPF MPCs. We show that IL-8 induces DNA damage and promotes IPF MPC senescence. We discovered that IL-8 concurrently promotes senescence and upregulation of the programmed death ligand 1 (PD-L1) in a CXCR2-dependent manner. Disruption of programmed cell death protein-1 (PD-1)-PD-L1 interaction promotes natural killer (NK) cell killing of IPF MPCs in vitro and arrests IPF MPC-mediated experimental lung fibrosis in vivo. Immunohistochemical (IHC) analysis of IPF lung tissue identified PD-L1-expressing IPF MPCs codistributing with NK cells and β-galactosidase-positive cells. Our data indicate that IL-8 simultaneously promotes IPF MPC DNA damage-induced senescence and high PD-L1 expression, enabling IPF MPCs to elude immune cell-targeted removal. Disruption of PD-1-PD-L1 interaction may limit IPF MPC-mediated fibrotic progression.NEW & NOTEWORTHY Here we show that IL-8 concurrently promotes senescence and upregulation of PD-L1 in IPF MPCs. IHC analysis identifies the presence of senescent IPF MPCs intermingled with NK cells in the fibroblastic focus, suggesting that senescent MPCs elude immune cell surveillance. We demonstrate that disruption of PD-1/PD-L1 interaction promotes NK cell killing of IPF MPCs and arrests IPF MPC-mediated experimental lung fibrosis. Disruption of PD-1/PD-L1 interaction may be one means to limit fibrotic progression.

DHMMF, a natural flavonoid from Resina Draconis, inhibits hepatocellular carcinoma progression via inducing apoptosis and G2/M phase arrest mediated by DNA damage-driven upregulation of p21

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide and is extremely malignant in nature. It is an important way to discover anti-cancer drugs from natural products at present. (R)-7,3'-dihydroxy-4'-methoxy-8-methylflavane (DHMMF), a natural flavonoid, was isolated from Resina Draconis which is the red resin from Dracaena cochinchinensis (Lour.) S. C. Chen. However, the anti-hepatoma effect and underlying mechanisms of DHMMF remain unclear. Herein, we demonstrated that DHMMF treatment significantly inhibited the proliferation of human hepatoma HepG2 and SK-HEP-1 cells. The IC₅₀ value of DHMMF for HepG2 and SK-HEP-1 cells were 0.67 μM and 0.66 μM, respectively, while the IC₅₀ value of DHMMF for human normal liver LO2 cells was 120.60 μM. DHMMF induced DNA damage, apoptosis, and G2/M phase arrest in HepG2 and SK-HEP-1 cells. Furthermore, the anti-proliferative and pro-apoptotic effects of DHMMF in human hepatoma cells were mediated by the upregulation of p21. Importantly, DHMMF exhibited potent anti-HCC efficacy in a xenograft mice model and an orthotopic mice model of liver cancer. Additionally, the combined administration of DHMMF and polo-like kinase 1 (PLK1) inhibitor BI 6727 showed a synergistic anti-HCC efficacy. Collectively, we demonstrated that DHMMF treatment induced apoptosis and G2/M phase arrest via DNA damage-driven upregulation of p21 expression in human hepatoma cells. DHMMF may serve as a promising drug candidate for HCC treatment, especially for patients of HCC with low p21 expression. Our results also suggested that DHMMF treatment in combination with PLK1 inhibitor may serve as a potential treatment strategy for patients with HCC.

Multifunctional metallochaperone modifications for targeting subsite cavities in mutant p53-Y220C

The p53 protein, known as the 'guardian of the genome', plays an important role in cancer prevention. Unfortunately, p53 mutations result in compromised activity with over 50% of cancers resulting from point mutations to p53. There is considerable interest in mutant p53 reactivation, with the development of small-molecule reactivators showing promise. We have focused our efforts on the common p53 mutation Y220C, which causes protein unfolding, aggregation, and can result in the loss of a structural Zn from the DNA-binding domain. In addition, the Y220C mutant creates a surface pocket that can be stabilized using small molecules. We previously reported the bifunctional ligand L5 as a Zn metallochaperone and reactivator of the p53-Y220C mutant. Herein we report two new ligands L5-P and L5-O that are designed to act as Zn metallochaperones and non-covalent binders in the Y220C mutant pocket. For L5-P the distance between the Zn-binding di-(2-picolyl)amine function and the pocket-binding diiodophenol was extended in comparison to L5, while for L5-O we extended the pocket-binding moiety via attachment of an alkyne function. While both new ligands displayed similar Zn-binding affinity to L5, neither acted as efficient Zn-metallochaperones. However, the new ligands exhibited significant cytotoxicity in the NCI-60 cell line screen as well as in the NUGC3 Y220C mutant cell line. We identified that the primary mode of cytotoxicity is likely reactive oxygen species (ROS) generation for L5-P and L5-O, in comparison to mutant p53 reactivation for L5, demonstrating that subtle changes to the ligand scaffold can change the toxicity pathway.

p53 promotes revival stem cells in the regenerating intestine after severe radiation injury

Ionizing radiation induces cell death in the gastrointestinal (GI) epithelium by activating p53. However, p53 also prevents animal lethality caused by radiation-induced GI injury. Through single-cell RNA-sequencing of the irradiated mouse intestine, we find that p53 target genes are specifically enriched in stem cells of the regenerating epithelium, including revival stem cells that promote animal survival after GI damage. Accordingly, in mice with p53 deleted specifically in the GI epithelium, ionizing radiation fails to induce revival stem cells. Using intestinal organoids, we show that transient p53 expression is required for the induction of revival stem cells that is controlled by an Mdm2-mediated negative feedback loop. These results suggest that p53 suppresses severe radiation-indued GI injury by promoting intestinal epithelial cell reprogramming.

One-Sentence Summary

After severe radiation injury to the intestine, transient p53 activity induces revival stem cells to promote regeneration.

A review on regulation of cell cycle by extracellular matrix

The extracellular matrix (ECM) is a network of structural proteins, glycoproteins and proteoglycans that assists independent cells in aggregating and forming highly organized functional structures. ECM serves numerous purposes and is an essential component of tissue structure and functions. Initially, the role of ECM was considered to be confined to passive functions like providing mechanical strength and structural identity to tissues, serving as barriers and platforms for cells. The doors to understanding ECM's proper role in tissue functioning opened with the discovery of cellular receptors, integrins to which ECM components binds and influences cellular activities. Understanding and utilizing ECM's potential to control cellular function has become a topic of much interest in recent decades, providing different outlooks to study processes involved in developmental programs, wound healing and tumour progression. On another front, the regulatory mechanisms operating to prevent errors in the cell cycle have been topics of a titanic amount of studies. This is expected as many diseases, most infamously cancer, are associated with defects in their functioning. This review focuses on how ECM, through different methods, influences the progression of the somatic cell cycle and provides deeper insights into molecular mechanisms of functional communication between adhesion complex, signalling pathways and cell cycle machinery.

Cerebral organoids in primary progressive multiple sclerosis reveal stem cell and oligodendrocyte differentiation defect

Multiple sclerosis (MS) is an auto-immune inflammatory disorder affecting the central nervous system. The cause of the disease is unknown but both genetic and environmental factors are implicated in the pathogenesis. We derived cerebral organoids from induced pluripotent stem cells (iPSC) of healthy control subjects as well as from primary progressive MS (PPMS), secondary progressive MS (SPMS) and relapsing remitting MS (RRMS) patients to better understand the pathologic basis of the varied clinical phenotypic expressions of MS. In MS organoids, most notably in PPMS, we observed a decrease of proliferation marker Ki67 and a reduction of the SOX2+ stem cell pool associated with an increased expression of neuronal markers CTIP2 and TBR1 as well as a strong decrease of oligodendrocyte differentiation. This dysregulation of the stem cell pool is associated with a decreased expression of the cell cycle inhibitor p21. Our findings show that the genetic background of a patient can directly alter stem cell function, provides new insights on the innate cellular dysregulation in MS and identifies p21 pathway as a new potential target for therapeutic strategies in MS.

Relative biological effectiveness of low-energy X-rays (25 kV) in mutant p53 cancer cells

Low-energy X-rays as used in radiation therapy and diagnostics such as mammography are associated with a certain risk of promoting tumour development, especially in patients with mutations in cancer-related genes like TP53. The present study therefore addressed the relative biological effectiveness (RBE) of low-energy X-rays for two human adenocarcinoma cell lines of the breast (MDA-MB-468) and pancreas (BxPC-3) with a mutation in the TP53 gene. Clonogenic survival and cytogenetic changes in terms of micronuclei (MN) formation were determined following irradiation with 25 kV X-rays and 200 kV reference irradiation in the dose range of 1-8 Gy. Except the frequency of MN-containing binucleated cells (BNC) (BNC + MN/BNC) in breast cancer cells yielding an RBE between 0.6 and 0.8, both cell lines displayed dose-dependent variations of RBE values between 1 and 2 for all biological end points (cell survival, (BNC + MN/BNC), MN/BNC, MN/(BNC + MN)) with increased effectiveness of 25 kV irradiation in pancreatic compared to breast cancer cells. The results confirm previous findings indicating increased effectiveness of low-energy X-rays and underline the necessity of careful risk estimation for cancer screening programmes.

Cell cycle regulators and bone: development and regeneration

Cell cycle regulators act as inhibitors or activators to prevent cancerogenesis. It has also been established that they can play an active role in differentiation, apoptosis, senescence, and other cell processes. Emerging evidence has demonstrated a role for cell cycle regulators in bone healing/development cascade. We demonstrated that deletion of p21, a cell cycle regulator acting at the G1/S transition enhanced bone repair capacity after a burr-hole injury in the proximal tibia of mice. Similarly, another study has shown that inhibition of p27 can increase bone mineral density and bone formation. Here, we provide a concise review of cell cycle regulators that influence cells like osteoblasts, osteoclasts, and chondrocytes, during development and/or healing of bone. It is imperative to understand the regulatory processes that govern cell cycle during bone healing and development as this will pave the way to develop novel therapies to improve bone healing after injury in instances of aged or osteoporotic fractures.

Neonatal hyperoxia induces activated pulmonary cellular states and sex-dependent transcriptomic changes in a model of experimental bronchopulmonary dysplasia

Hyperoxia disrupts lung development in mice and causes bronchopulmonary dysplasia (BPD) in neonates. To investigate sex-dependent molecular and cellular programming involved in hyperoxia, we surveyed the mouse lung using single cell RNA sequencing (scRNA-seq), and validated our findings in human neonatal lung cells in vitro. Hyperoxia-induced inflammation in alveolar type (AT) 2 cells gave rise to damage-associated transient progenitors (DATPs). It also induced a new subpopulation of AT1 cells with reduced expression of growth factors normally secreted by AT1 cells, but increased mitochondrial gene expression. Female alveolar epithelial cells had less EMT and pulmonary fibrosis signaling in hyperoxia. In the endothelium, expansion of Car4+ EC (Cap2) was seen in hyperoxia along with an emergent subpopulation of Cap2 with repressed VEGF signaling. This regenerative response was increased in females exposed to hyperoxia. Mesenchymal cells had inflammatory signatures in hyperoxia, with a new distal interstitial fibroblast subcluster characterized by repressed lipid biosynthesis and a transcriptomic signature resembling myofibroblasts. Hyperoxia-induced gene expression signatures in human neonatal fibroblasts and alveolar epithelial cells in vitro resembled mouse scRNA-seq data. These findings suggest that neonatal exposure to hyperoxia programs distinct sex-specific stem cell progenitor and cellular reparative responses that underpin lung remodeling in BPD.

Evodiamine inhibits ESCC by inducing M-phase cell-cycle arrest via CUL4A/p53/p21 axis and activating noxa-dependent intrinsic and DR4-dependent extrinsic apoptosis

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is a malignancy with high incidence in several regions of China, and the prognosis of patients with ESCC is unfavorable. Evodiamine (Evo), a small molecule derived from the traditional Chinese herb Evodia rutaecarpa, has shown anti-cancer efficacy in numerous human malignancies but not in ESCC.

PURPOSE

To determine whether Evo induces cell-cycle arrest and apoptosis in ESCC in vitro and in vivo and elucidate the underlying mechanisms.

METHODS

ATPlite and colony formation assay were used to validate the inhibiting effect of Evo on three ESCC cells in vitro; Two subcutaneous tumor models of ESCC cells were used to evaluate the anti-ESCC effect of Evo and assess the biosafety of Evo in vivo; RNAseq and Database of KEGG pathway analysis provided a direction for the mechanistic study of Evo; FACS was used to detect Evo-induced cell cycle arrest and cell apoptosis in ESCC cells; Western blot and QPCR were respectively used to detect the level of related genes and proteins in Evo-treated ESCC cells; SiRNA and other experimental techniques were used to identify the molecular mechanism of Evo-induced ESCC cell cycle arrest and cell apoptosis.

RESULTS

Evo significantly suppressed the growth of ESCC both in vitro and in vivo. Mechanistically, Evo induced M-phase cell-cycle arrest by inactivation of CUL4A E3 ligase, which mediates degradation blockage of p53 and transcriptional activation of p21. With the prolonged treatment time, Evo triggered both Noxa-dependent intrinsic and DR4-dependent extrinsic cell apoptosis in two ESCC cell lines.

CONCLUSION

Our findings revealed the anti-tumor efficacy and mechanisms of Evo, providing a solid scientific basis for Evo as an attractive choice for ESCC treatment.

Alternative transcribed 3' isoform of long non-coding RNA Malat1 inhibits mouse retinal oxidative stress

The function of the cancer-associated lncRNA Malat1 during aging is as-of-yet uncharacterized. Here, we show that Malat1 interacts with Nucleophosmin (NPM) in young mouse brain, and with Lamin A/C, hnRNP C, and KAP1 with age. RNA-seq and RT-qPCR reveal a persistent expression of Malat1_2 (the 3'isoform of Malat1) in Malat1Δ1 (5'-1.5 kb deletion) mouse retinas and brains at 1/4^th level of the full-length Malat1, while Malat1_1 (the 5'isoform) in Malat1Δ2 (deletion of 3'-conserved 5.7 kb) at a much lower level, suggesting an internal promoter driving the 3' isoform. The 1774 and 496 differentially expressed genes in Malat1Δ2 and Malat1Δ1 brains, respectively, suggest the 3' isoform regulates gene expression in trans and the 5' isoform in cis. Consistently, Malat1Δ2 mice show increased age-dependent retinal oxidative stress and corneal opacity, while Malat1Δ1 mice show no obvious phenotype. Collectively, this study reveals a physiological function of the lncRNA Malat1 3'-isoform during the aging process.

How safe are magnetic nanomotors: From cells to animals

Helical magnetic nanomotors can be actuated using an external magnetic field and have potential applications in drug delivery, colloidal manipulation, and bio-microrheology. Recently, they have been maneuvered in biological environments such as vitreous humour, dentinal tubules, peritoneal fluid, stromal matrix, and blood, which are promising developments for clinical applications. However, their biocompatibility and biodistribution are vital parameters that must be assessed before further use. An extensive quantitative evaluation has been performed for these parameters for the first time through in vitro and in vivo experiments. Investigations of cell death, proliferation, and DNA damage ascertain that the motors are non-toxic. Also, an unbiased transcriptomic analysis affirms that the motors are not genotoxic till 20 motors/ cell. Toxicity studies in mice reveal that the motors show no signs of toxicity up to a dose of 55 mg/ kg body weight. Further, the biodistribution studies show that they remain in the blood circulation after injection and at later stages possibly adhere to the walls of the blood vessel because of adsorption. However, perfusion with physiological saline decreases this adsorption/adhesion. Overall, we demonstrate the biocompatibility of nanomotors in live cellular and organismal systems, and a systemic biodistribution analysis reveals organ-specific retention of motors.

Reduction of lithium induced interstitial fibrosis on co-administration with amiloride

Long-term administration of lithium is associated with chronic interstitial fibrosis that is partially reduced with exposure to amiloride. We examined potential pathways of how amiloride may reduce interstitial fibrosis. Amiloride was administered to a rat model of lithium induced interstitial fibrosis over a long term (6 months), as well as for short terms of 14 and 28 days. Kidney cortical tissue was subjected to RNA sequencing and microRNA expression analysis. Gene expression changes of interest were confirmed using immunohistochemistry on kidney tissue. Pathways identified by RNA sequencing of kidney tissue were related to 'promoting inflammation' for lithium and 'reducing inflammation' for amiloride. Validation of candidate genes found amiloride reduced inflammatory components induced by lithium including NF-κB/p65^Ser536 and activated pAKT^Ser473, and increased p53 mediated regulatory function through increased p21 in damaged tubular epithelial cells. Amiloride also reduced the amount of Notch1 positive PDGFrβ pericytes and infiltrating CD3 cells in the interstitium. Thus, amiloride attenuates a multitude of pro-inflammatory components induced by lithium. This suggests amiloride could be repurposed as a possible anti-inflammatory, anti-fibrotic agent to prevent or reduce the development of chronic interstitial fibrosis.

From cyclins to CDKIs: Cell cycle regulation of skeletal muscle stem cell quiescence and activation

After extensive proliferation during development, the adult skeletal muscle cells remain outside the cell cycle, either as post-mitotic myofibers or as quiescent muscle stem cells (MuSCs). Despite its terminally differentiated state, adult skeletal muscle has a remarkable regeneration potential, driven by MuSCs. Upon injury, MuSC quiescence is reversed to support tissue growth and repair and it is re-established after the completion of muscle regeneration. The distinct cell cycle states and transitions observed in the different myogenic populations are orchestrated by elements of the cell cycle machinery. This consists of i) complexes of cyclins and Cyclin-Dependent Kinases (CDKs) that ensure cell cycle progression and ii) their negative regulators, the Cyclin-Dependent Kinase Inhibitors (CDKIs). In this review we discuss the roles of these factors in developmental and adult myogenesis, with a focus on CDKIs that have emerging roles in stem cell functions.

PI3Kδ activity controls plasticity and discriminates between EMT and stemness based on distinct TGFβ signaling

The stem cells involved in formation of the complex human body are epithelial cells that undergo apicobasal polarization and form a hollow lumen. Epithelial plasticity manifests as epithelial to mesenchymal transition (EMT), a process by which epithelial cells switch their polarity and epithelial features to adopt a mesenchymal phenotype. The connection between the EMT program and acquisition of stemness is now supported by a substantial number of reports, although what discriminates these two processes remains largely elusive. In this study, based on 3D organoid culture of hepatocellular carcinoma (HCC)-derived cell lines and AAV8-based protein overexpression in the mouse liver, we show that activity modulation of isoform δ of phosphoinositide 3-kinase (PI3Kδ) controls differentiation and discriminates between stemness and EMT by regulating the transforming growth factor β (TGFβ) signaling. This study provides an important tool to control epithelial cell fate and represents a step forward in understanding the development of aggressive carcinoma.

Radiosensitizing effect of dendrosomal nanoformulation of curcumin on cancer cells

BACKGROUND

Curcumin was found to possess numerous pharmacological activities in clinical research, however, its biological effects together with radiation are yet to be addressed. The present study investigated whether the combined treatment of dendrosomal nanoformulation of curcumin (DNC) and gamma radiation can enhance the radiosensitivity of U87MG and MDA-MB-231 cell lines.

METHODS

U87MG and MDA-MB-231 cell lines were exposed to 2 Gray (Gy) and 10 μM DNC determined by MTT assay, then subjected to clonogenic assay, cell cycle assay, and flow cytometric apoptosis analysis. Acridine Orange/Ethidium Bromide (AO/EB) and 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) stained cells were used to study morphologic changes. The expression evaluation of putative cell cycle genes, i.e., P53, P21, CCND1, and CCNB1 was carried out by RT-qPCR.

RESULTS

Our findings indicated that the combined treatment with DNC and radiation might cooperatively augment the efficacy of ionizing radiation in the cancer cells and notably decrease the survival and viability of the cells in a time- and concentration-dependent manner. In addition to a synergistic effect deducted by sensitizer enhancement ratio (SER) assessment, co-treatment resulted in greater apoptotic cells than the individual treatments. Further experiments then indicated that DNC could effectively induce G2/M phase cell cycle arrest and apoptosis following irradiation. Conformably, there was a decrement of CCND1 and CCNB1 expression, and an increment of P53, P21 expression.

CONCLUSIONS

The data implied that DNC as a radiosensitizer can enhance the lethal effect of ionizing radiation on cancer cells which could be a promising adjuvant therapy in clinical treatments.

Quantitative profiling of adaptation to cyclin E overproduction

Cyclin E/CDK2 drives cell cycle progression from G1 to S phase. Despite the toxicity of cyclin E overproduction in mammalian cells, the cyclin E gene is overexpressed in some cancers. To further understand how cells can tolerate high cyclin E, we characterized non-transformed epithelial cells subjected to chronic cyclin E overproduction. Cells overproducing cyclin E, but not cyclins D or A, briefly experienced truncated G1 phases followed by a transient period of DNA replication origin underlicensing, replication stress, and impaired proliferation. Individual cells displayed substantial intercellular heterogeneity in cell cycle dynamics and CDK activity. Each phenotype improved rapidly despite high cyclin E-associated activity. Transcriptome analysis revealed adapted cells down-regulated a cohort of G1-regulated genes. Withdrawing cyclin E from adapted cells only partially reversed underlicensing indicating that adaptation is at least partly non-genetic. This study provides evidence that mammalian cyclin E/CDK inhibits origin licensing indirectly through premature S phase onset and provides mechanistic insight into the relationship between CDKs and licensing. It serves as an example of oncogene adaptation that may recapitulate molecular changes during tumorigenesis.

A role for bioinorganic chemistry in the reactivation of mutant p53 in cancer

Metal ion dysregulation has been implicated in a number of diseases from neurodegeneration to cancer. While defective metal ion transport mechanisms are known to cause specific diseases of genetic origin, the role of metal dysregulation in many diseases has yet to be elucidated due to the complicated function (both good and bad!) of metal ions in the body. A breakdown in metal ion speciation can manifest in several ways from increased reactive oxygen species (ROS) generation to an increase in protein misfolding and aggregation. In this review, we will discuss the role of Zn in the proper function of the p53 protein in cancer. The p53 protein plays a critical role in the prevention of genome mutations via initiation of apoptosis, DNA repair, cell cycle arrest, anti-angiogenesis, and senescence pathways to avoid propagation of damaged cells. p53 is the most frequently mutated protein in cancer and almost all cancers exhibit malfunction along the p53 pathway. Thus, there has been considerable effort dedicated to restoring normal p53 expression and activity to mutant p53. This includes understanding the relative populations of the Zn-bound and Zn-free p53 in wild-type and mutant forms, and the development of metallochaperones to re-populate the Zn binding site to restore mutant p53 activity. Parallels will be made to the development of multifunctional metal binding agents for modulating the aggregation of the amyloid-beta peptide in Alzheimer's Disease (AD).

IFN-γ and TNF Induce Senescence and a Distinct Senescence-Associated Secretory Phenotype in Melanoma

Immune checkpoint blockade (ICB) therapy is a central pillar of melanoma treatment leading to durable response rates. Important mechanisms of action of ICB therapy include disinhibition of CD4+ and CD8+ T cells. Stimulated CD4+ T helper 1 cells secrete the effector cytokines interferon-gamma (IFN-γ) and tumor necrosis factor alpha (TNF), which induce senescence in tumor cells. Besides being growth-arrested, senescent cells are metabolically active and secrete a large spectrum of factors, which are summarized as senescence-associated secretory phenotype (SASP). This secretome affects the tumor growth. Here, we compared the SASP of cytokine-induced senescent (CIS) cells with the SASP of therapy-induced senescent (TIS) cells. Therefore, we established in vitro models for CIS and TIS in melanoma. The human melanoma cell lines SK-MEL-28 and WM115 were treated with the cytokines IFN-γ and TNF as CIS, the chemotherapeutic agent doxorubicin, and the cell cycle inhibitor palbociclib as TIS. Then, we determined several senescence markers, i.e., growth arrest, p21 expression, and senescence-associated β-galactosidase (SA-β-gal) activity. For SASP analyses, we measured the regulation and secretion of several common SASP factors using qPCR arrays, protein arrays, and ELISA. Each treatment initiated a stable growth arrest, enhanced SA-β-gal activity, and—except palbociclib—increased the expression of p21. mRNA and protein analyses revealed that gene expression and secretion of SASP factors were severalfold stronger in CIS than in TIS. Finally, we showed that treatment with the conditioned media (CM) derived from cytokine- and palbociclib-treated cells induced senescence characteristics in melanoma cells. Thus, we conclude that senescence induction via cytokines may lead to self-sustaining senescence surveillance of melanoma.