Inhibition of SRGAP2 function by its human-specific paralogs induces neoteny during spine maturation.

Structural genomic variations represent a major driving force of evolution, and a burst of large segmental gene duplications occurred in the human lineage during its separation from nonhuman primates. SRGAP2, a gene recently implicated in neocortical development, has undergone two human-specific duplications. Here, we find that both duplications (SRGAP2B and SRGAP2C) are partial and encode a truncated F-BAR domain. SRGAP2C is expressed in the developing and adult human brain and dimerizes with ancestral SRGAP2 to inhibit its function. In the mouse neocortex, SRGAP2 promotes spine maturation and limits spine density. Expression of SRGAP2C phenocopies SRGAP2 deficiency. It underlies sustained radial migration and leads to the emergence of human-specific features, including neoteny during spine maturation and increased density of longer spines. These results suggest that inhibition of SRGAP2 function by its human-specific paralogs has contributed to the evolution of the human neocortex and plays an important role during human brain development.

The F-BAR domain of srGAP2 induces membrane protrusions required for neuronal migration and morphogenesis.

During brain development, proper neuronal migration and morphogenesis is critical for the establishment of functional neural circuits. Here we report that srGAP2 negatively regulates neuronal migration and induces neurite outgrowth and branching through the ability of its F-BAR domain to induce filopodia-like membrane protrusions resembling those induced by I-BAR domains in vivo and in vitro. Previous work has suggested that in nonneuronal cells filopodia dynamics decrease the rate of cell migration and the persistence of leading edge protrusions. srGAP2 knockdown reduces leading process branching and increases the rate of neuronal migration in vivo. Overexpression of srGAP2 or its F-BAR domain has the opposite effects, increasing leading process branching and decreasing migration. These results suggest that F-BAR domains are functionally diverse and highlight the functional importance of proteins directly regulating membrane deformation for proper neuronal migration and morphogenesis.

Diapause-like Drug-Tolerant Persister State: The Key to Nirvana Rebirth.

Cancer is one of the leading causes of death in the world. Various drugs have been developed to eliminate it but to no avail because a tumor can go into dormancy to avoid therapy. In the past few decades, tumor dormancy has become a popular topic in cancer therapy. Recently, there has been an important breakthrough in the study of tumor dormancy. That is, cancer cells can enter a reversible drug-tolerant persister (DTP) state to avoid therapy, but no exact mechanism has been found. The study of the link between the DTP state and diapause seems to provide an opportunity for a correct understanding of the mechanism of the DTP state. Completely treating cancer and avoiding dormancy by targeting the expression of key genes in diapause are possible. This review delves into the characteristics of the DTP state and its connection with embryonic diapause, and possible treatment strategies are summarized. The authors believe that this review will promote the development of cancer therapy.

CircCPSF6 promotes hepatocellular carcinoma cancer progression by regulating MAP4K4 through sponging miR-145-5p.

BACKGROUND: Aberrant expression of circRNAs is involved in the progression of hepatocellular carcinoma (HCC). This study aimed at screening the pro-tumorigenic circular RNAs (circRNAs) in HCC and the mechanisms of circCPSF6 expression influencing HCC characteristics. METHOD: circCPSF6 was identified in HCC tissues using high-throughput sequencing data, and its expression was verified in both HCC tissues and cell lines using quantitative real-time PCR (qRT-PCR). CCK-8 and Transwell assays were used to evaluate the effects of circCPSF6 on HCC proliferation and migration. A xenograft mouse model was used to investigate the effects of circCPSF6 on HCC progression in vivo, and the significance of circCPSF6 in HCC was verified both in vivo and in vitro. circCPSF6-associated miRNAs and mRNAs were identified using bioinformatic analyses. Luciferase reporter, RNA pull-down, Fluorescence in situ hybridization, and RNA immunoprecipitation assays were performed to elucidate the circCPSF6 regulatory axis in HCC. RESULT: CircCPSF6 expression was increased in HCC cell lines and tissues, and the expression of its parental mRNA was positively correlated with tumor severity and negatively correlated with survival. Mechanistic analyses of HCC cell lines showed that tumorigenesis was inhibited by circCPSF6 knockdown and promoted by its overexpression. Functional analyses revealed that circCPSF6 mediated HCC development by sponging miR-145-5p as a competing endogenous RNA. Furthermore, this sponging upregulated the miR-145-5p target gene MAP4K4, a classical pro-tumorigenic gene. CONCLUSION: Our findings reveal a regulatory network that includes the circCPSF6-miR-145-5p-MAP4K4 axis. Elements of this axis are potential HCC biomarkers, as well as targets for HCC treatment.

NEK7 promotes gastric cancer progression as a cell proliferation regulator.

BACKGROUND: Gastric cancer is one of the most common malignant tumors of the digestive system. However, its targeted therapy develops at a slow pace. Thus, exploring the mechanisms of the malignant behavior of gastric cancer cells is crucial to exploit its treatment. Mammalian never-in-mitosis A (NIMA)-related kinases (NEKs) are considered to play a significant role in cancer cell proliferation. However, no study has reported on NIMA family proteins in gastric cancer. METHODS: Bioinformatics analysis was employed to clarify the expression patterns of NEK1-NEK11 and their effects on prognosis. The effects of NEK7 on immune infiltration and NEK7 related pathways were also analyzed. At the cell level, 5-ethynyl-2-deoxyuridine, cell cycle, and Cell Counting Kit-8 assays were utilized to clarify the effect of NEK7 on gastric cancer cell proliferation. A mouse subcutaneous model revealed the regulating effect of NEK7 on gastric cancer cell proliferation in vivo. RESULTS: Bioinformatics analysis revealed that NEK7 is upregulated in gastric cancer and is related to poor prognosis. NEK7 is also related to T-stage, which is closely associated with cell proliferation. Further analysis showed that NEK7 was correlated with infiltration of multiple immune cells as well as gastric cancer-related pathways. Cell experiments indicated the promoting effect of NEK7 on cell proliferation, while the absence of NEK7 could lead to inhibition of gastric cancer proliferation and G1/S arrest. CONCLUSION: NEK7 exerts a regulatory effect on cell proliferation and is closely related to tumor immune infiltration.

Au-siRNA@ aptamer nanocages as a high-efficiency drug and gene delivery system for targeted lung cancer therapy.

BACKGROUND: Gene and chemical therapy has become one of the rising stars in the field of molecular medicine during the last two decades. However, there are still numerous challenges in the development of efficient, targeted, and safe delivery systems that can avoid siRNA degradation and reduce the toxicity and adverse effects of chemotherapy medicine. RESULTS: In this paper, a highly efficient AS1411 aptamer modified, dsDNA and MMP-2 cleavable peptide-fabricated gold nanocage vehicle, which could load doxorubicin hydrochloride (DOX) and siRNAs to achieve a combination of tumor responsive genetic therapy, chemotherapy, and photothermal treatment is presented. Our results show that this combined treatment achieved targeted gene silencing and tumor inhibition. After nearly one month of treatment with DOX-loaded Au-siRNA-PAA-AS1411 nanoparticles with one dose every three days in mice, a synergistic effect promoting the eradication of long-lived tumors was observed along with an increased survival rate of mice. The combined genetic, chemotherapeutic, and photothermal treatment group exhibited more than 90% tumor inhibition ratio (tumor signal) and a ~ 67% survival rate compared with a 30% tumor inhibition ratio and a 0% survival rate in the passive genetic treatment group. CONCLUSIONS: The development of nanocarriers with double-stranded DNA and MMP-2 cleavable peptides provides a new strategy for the combined delivery of gene and chemotherapy medicine. Au-siRNA-PAA-AS1411 exerts high anticancer activities on lung cancer, indicating immense potentials for clinical application.

Photoactivatable RNA N6 -Methyladenosine Editing with CRISPR-Cas13.

RNA has important and diverse biological roles, but the molecular methods to manipulate it spatiotemporally are limited. Here, an engineered photoactivatable RNA N6 -methyladenosine (m6 A) editing system with CRISPR-Cas13 is designed to direct specific m6 A editing. Light-inducible heterodimerizing proteins CIBN and CRY2PHR are fused to catalytically inactive PguCas13 (dCas13) and m6 A effectors, respectively. This system, referred to as PAMEC, enables the spatiotemporal control of m6 A editing in response to blue light. Further optimization of this system to create a highly efficient version, known as PAMECR , allows the manipulation of multiple genes robustly and simultaneously. When coupled with an upconversion nanoparticle film, the optogenetic operation window is extended from the visible range to tissue-penetrable near-infrared wavelengths, which offers an appealing avenue to remotely control RNA editing. These results show that PAMEC is a promising optogenetic platform for flexible and efficient targeting of RNA, with broad applicability for epitranscriptome engineering, imaging, and future therapeutic development.

Circulating tumor cells in precision oncology: clinical applications in liquid biopsy and 3D organoid model.

Circulating tumor cells (CTCs) are a rare subset of cells found in the blood of patients with solid tumors, which function as a seed for metastases. Cancer cells metastasize through the bloodstream either as single migratory CTCs or as multicellular groupings-CTC clusters. The CTCs preserve primary tumor heterogeneity and mimic tumor properties, and may be considered as clinical biomarker, preclinical model, and therapeutic target. The potential clinical application of CTCs is being a component of liquid biopsy. CTCs are also good candidates for generating preclinical models, especially 3D organoid cultures, which could be applied in drug screening, disease modeling, genome editing, tumor immunity, and organoid biobanks. In this review, we summarize current knowledge on the value and promise of evolving CTC technologies and highlight cutting-edge research on CTCs in liquid biopsy, tumor metastasis, and organoid preclinical models. The study of CTCs offers broad pathways to develop new biomarkers for tumor patient diagnosis, prognosis, and response to therapy, as well as translational models accelerating oncologic drug development.

Ubiquitin-specific protease 22 acts as an oncoprotein to maintain glioma malignancy through deubiquitinating B cell-specific Moloney murine leukemia virus integration site 1 for stabilization.

Ubiquitin-specific protease 22 (USP22) is a member of the "death-from-cancer" signature, which plays a key role in cancer progression. Previous evidence has shown that USP22 is overexpressed and correlates with poor prognosis in glioma. The effect and mechanism of USP22 in glioma malignancy, especially cancer stemness, remain elusive. Herein, we find USP22 is more enriched in stem-like tumorspheres than differentiated glioma cells. USP22 knockdown inhibits cancer stemness in glioma cell lines. With a cell-penetrating TAT-tag protein, B cell-specific Moloney murine leukemia virus integration site 1 (BMI1), a robust glioma stem-cell marker, is found to mediate the effect of USP22 on glioma stemness. By immunofluorescence, USP22 and BMI1 are found to share similar intranuclear expression in glioma cells. By analysis with immunohistochemistry and bioinformatics, USP22 is found to positively correlate with BMI1 at the post-translational level only rather than at the transcriptional level. By immunoprecipitation and in vivo deubiquitination assay, USP22 is found to interact with and deubiquitinate BMI1 for protein stabilization. Microarray analysis shows that USP22 and BMI1 mutually regulate a series of genes involved in glioma stemness such as POSTN, HEY2, PDGFRA and ATF3. In vivo study with nude mice confirms the role of USP22 in promoting glioma tumorigenesis by regulating BMI1. All these findings indicate USP22 as a novel deubiquitinase of BMI1 in glioma. We propose a working model of the USP22-BMI1 axis, which promotes glioma stemness and tumorigenesis through oncogenic activation. Thus, targeting USP22 might be an effective strategy to treat glioma especially in those with elevated BMI1 expression.

Targeting Deubiquitinating Enzymes in Glioblastoma Multiforme: Expectations and Challenges.

Glioblastoma (GBM) is regarded as the most common primary intracranial neoplasm. Despite standard treatment with tumor resection and radiochemotherapy, the outcome remains gloomy. It is evident that a combination of oncogenic gain of function and tumor-suppressive loss of function has been attributed to glioma initiation and progression. The ubiquitin-proteasome system is a well-orchestrated system that controls the fate of most proteins by striking a dynamic balance between ubiquitination and deubiquitination of substrates, having a profound influence on the modulation of oncoproteins, tumor suppressors, and cellular signaling pathways. In recent years, deubiquitinating enzymes (DUBs) have emerged as potential anti-cancer targets due to their targeting several key proteins involved in the regulation of tumorigenesis, apoptosis, senescence, and autophagy. This review attempts to summarize recent studies of GBM-associated DUBs, their roles in various cellular processes, and discuss the relation between DUBs deregulation and gliomagenesis, especially how DUBs regulate glioma stem cells pluripotency, microenvironment, and resistance of radiation and chemotherapy through core stem-cell transcriptional factors. We also review recent achievements and progress in the development of potent and selective reversible inhibitors of DUBs, and attempted to find a potential GBM treatment by DUBs intervention.

Olig1 Acetylation and Nuclear Export Mediate Oligodendrocyte Development.

The oligodendrocyte transcription factor Olig1 is critical for both oligodendrocyte development and remyelination in mice. Nuclear to cytoplasmic translocation of Olig1 protein occurs during brain development and in multiple sclerosis, but the detailed molecular mechanism of this translocation remains elusive. Here, we report that Olig1 acetylation and deacetylation drive its active translocation between the nucleus and the cytoplasm in both mouse and rat oligodendrocytes. We identified three functional nuclear export sequences (NES) localized in the basic helix-loop-helix domain and one specific acetylation site at Lys 150 (human Olig1) in NES1. Olig1 acetylation and deacetylation are regulated by the acetyltransferase CREB-binding protein and the histone deacetylases HDAC1, HDAC3, and HDAC10. Acetylation of Olig1 decreased its chromatin association, increased its interaction with inhibitor of DNA binding 2 and facilitated its retention in the cytoplasm of mature oligodendrocytes. These studies establish that acetylation of Olig1 regulates its chromatin dissociation and subsequent translocation to the cytoplasm and is required for its function in oligodendrocyte maturation.

Anti-tumor activity of phenoxybenzamine hydrochloride on malignant glioma cells.

Phenoxybenzamine hydrochloride (PHEN) is a selective antagonist of both α-adrenoceptor and calmodulin that exhibits anticancer properties. The aim of this study was to explore the anti-tumor function of PHEN in glioma. Cell proliferation assay was used to assess glioma cell growth. Migration and invasion capacity of glioma cells was monitored by wound-healing and transwell assay, respectively. Neurosphere formation test was adopted for the tumorigenesis of glioma cells, which was also confirmed by soft agar cloning formation test in vitro and a nude mouse model in vivo. Finally, we explored the potential pathway utilized by PHEN using Western blot and immunofluoresce staining. PHEN exhibited a significant inhibitory effect on the proliferation of both U251 and U87MG glioma cell lines in a positive dose-dependent manner. PHEN apparently attenuated the malignancy of glioma in terms of migration and invasion and also suppressed the tumorigenic capacity both in vitro and in vivo. Mechanism study showed that PHEN promoted tumor suppression by inhibiting the TrkB-Akt pathway. The results of the present study demonstrated that PHEN suppressed the proliferation, migration, invasion, and tumorigenesis of glioma cells, induced LINGO-1 expression, and inhibited the TrkB-Akt pathway, which may prove to be the mechanisms underlying the anti-tumor effect of PHEN on glioma cells.

The Emerging Therapeutic Role of NGF in Alzheimer's Disease.

Alzheimer's disease (AD) is the most common type of neurodegenerative dementia that affects the elderly population. Nerve growth factor (NGF) contributes to the survival, regeneration and death of neurons during aging and in neurodegenerative diseases. Recently, research has shown that NGF is related to the pathology, mechanisms and symptoms of AD. Therefore, there is a need to summarize the new advancements in NGF research and its potential therapeutic implications in AD. In this review, we will focus on NGF distribution, production, and function; the interaction of Aß and NGF; and the effect of different therapy methods on AD. In summary, we hope to describe the experimental and clinical data demonstrating the important roles of NGF for AD treatment.

A link between the nuclear-localized srGAP3 and the SWI/SNF chromatin remodeler Brg1.

The Slit-Robo GTPase activating protein 3 (srGAP3) is an important modulator of actin cytoskeletal dynamics and has an important influence on a variety of neurodevelopmental processes. Mutations in the SRGAP3 gene on chromosome 3p25 have been found in patients with intellectual disability. Genome-wide association studies and behavioral assays of knockout mice had also revealed SRGAP3 as a risk gene for schizophrenia. We have recently shown that srGAP3 protein undergoes regulated shuttling between the cytoplasm and the nucleus during neuronal development. It is shown here that nuclear-localized srGAP3 interacts with the SWI/SNF remodeling factor Brg1. This interaction is mediated by the C-terminal of srGAP3 and the ATPase motif of Brg1. In the primary cultured rat cortical neurons, the levels of nuclear-localized srGAP3 and its interaction with Brg1 have a significant impact on dendrite complexity. Furthermore, the interaction between srGAP3 and Brg1 was also involved in valproic acid (VPA) -induced neuronal differentiation of Neuro2a cells. We then show that GTP-bound Rac1 and GAP-43 may be potential mediators of nuclear srGAP3 and Brg1. Our results not only indicate a novel signaling pathway that contributes to neuronal differentiation and dendrite morphology, but also implicate a novel molecular mechanism underlying srGAP3 regulation of gene expression.

A Novel Function of TET2 in CNS: Sustaining Neuronal Survival.

DNA dioxygenases Ten-Eleven Translocation (TET) proteins can catalyze the conversion of 5-methylcytosine (5mC) of DNA to 5-hydroxymethylcytosine (5hmC), and thereby alter the epigenetic state of DNA. The TET family includes TET1, TET2 and TET3 members in mammals. Recently, accumulative research uncovered that TET1-3 occur abundantly in the central nervous system (CNS), and their biological functions have just begun to be investigated. In the present study, we demonstrated that mRNA and protein of TET2 were highly expressed in the cerebral cortex and hippocampus along the whole brain-development process. Further studies showed that TET2 was expressed in various types of cells, especially in most neurons. Subcellular distribution pattern implicated that TET2 is localized in both nucleus and cytoplasm of neurons. Down-regulation of TET2 in cultured cortical neurons with RNA interference implied that TET2 was required for cell survival. In all, our results indicate that neuronal TET2 is positively involved in the regulation of cell survival.

Dynamics of ten-eleven translocation hydroxylase family proteins and 5-hydroxymethylcytosine in oligodendrocyte differentiation.

The ten-eleven translocation (TET) family of methylcytosine dioxygenases catalyze oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) and promote DNA demethylation. Despite the abundance of 5hmC and TET proteins in the brain, little is known about their role in oligodendrocytes (OLs). Here, we analyzed TET expression during OL development in vivo and in vitro, and found that three TET family members possess unique subcellular and temporal expression patterns. Furthermore, the level of 5hmC exhibits dynamic changes during OL maturation, which implies that 5hmC modification may play a role in the expression of critical genes necessary for OL maturation. siRNA-mediated silencing of the TET family proteins in OLs demonstrated that each of the TET proteins is required for OL differentiation. However, based on their unique domain structures, we speculate that the three TET members may function by different mechanisms. In summary, we have established the temporal expression of TET proteins and the dynamic level of 5hmC during OL development and demonstrate that all three TET members are necessary for OL differentiation.

LEF1 regulates glioblastoma cell proliferation, migration, invasion, and cancer stem-like cell self-renewal.

Glioblastoma multiforme (GBM; WHO grade IV) is one of the most common primary tumors of the central nervous system. This disease remains one of the incurable human malignancies because the molecular mechanism driving the GBM development and recurrence is still largely unknown. Here, we show that knockdown of lymphocyte enhancer factor-1 (LEF1), a major transcription factor of Wnt pathway, inhibits U251 cell migration, invasion, and proliferation. Furthermore, downregulation of LEF1 expression inhibits the self-renewal capacity of U251 GBM stem-like cells and decreases the expression level of the GBM stem-like cell (GSC) markers such as CD133 and nestin. Our findings reveal that LEF1 maintains the GBM cell proliferation, migration, and GBM stem-like cell self-renewal. Taken together, these results suggest that LEF1 may be a novel therapeutic target for GBM suppression.

Cancer cachexia: Focus on cachexia factors and inter-organ communication.

ABSTRACT: Cancer cachexia is a multi-organ syndrome and closely related to changes in signal communication between organs, which is mediated by cancer cachexia factors. Cancer cachexia factors, being the general name of inflammatory factors, circulating proteins, metabolites, and microRNA secreted by tumor or host cells, play a role in secretory or other organs and mediate complex signal communication between organs during cancer cachexia. Cancer cachexia factors are also a potential target for the diagnosis and treatment. The pathogenesis of cachexia is unclear and no clear effective treatment is available. Thus, the treatment of cancer cachexia from the perspective of the tumor ecosystem rather than from the perspective of a single molecule and a single organ is urgently needed. From the point of signal communication between organs mediated by cancer cachexia factors, finding a deeper understanding of the pathogenesis, diagnosis, and treatment of cancer cachexia is of great significance to improve the level of diagnosis and treatment. This review begins with cancer cachexia factors released during the interaction between tumor and host cells, and provides a comprehensive summary of the pathogenesis, diagnosis, and treatment for cancer cachexia, along with a particular sight on multi-organ signal communication mediated by cancer cachexia factors. This summary aims to deepen medical community's understanding of cancer cachexia and may conduce to the discovery of new diagnostic and therapeutic targets for cancer cachexia.

Cholesterol metabolism in tumor microenvironment: cancer hallmarks and therapeutic opportunities.

Cholesterol is crucial for cell survival and growth, and dysregulation of cholesterol homeostasis has been linked to the development of cancer. The tumor microenvironment (TME) facilitates tumor cell survival and growth, and crosstalk between cholesterol metabolism and the TME contributes to tumorigenesis and tumor progression. Targeting cholesterol metabolism has demonstrated significant antitumor effects in preclinical and clinical studies. In this review, we discuss the regulatory mechanisms of cholesterol homeostasis and the impact of its dysregulation on the hallmarks of cancer. We also describe how cholesterol metabolism reprograms the TME across seven specialized microenvironments. Furthermore, we discuss the potential of targeting cholesterol metabolism as a therapeutic strategy for tumors. This approach not only exerts antitumor effects in monotherapy and combination therapy but also mitigates the adverse effects associated with conventional tumor therapy. Finally, we outline the unresolved questions and suggest potential avenues for future investigations on cholesterol metabolism in relation to cancer.

The cellular-centered view of hypoxia tumor microenvironment: Molecular mechanisms and therapeutic interventions.

Cancer is a profoundly dynamic, heterogeneous and aggressive systemic ailment, with a coordinated evolution of various types of tumor niches. Hypoxia plays an indispensable role in the tumor micro-ecosystem, drastically enhancing the plasticity of cancer cells, fibroblasts and immune cells and orchestrating intercellular communication. Hypoxia-induced signals, particularly hypoxia-inducible factor-1α (HIF-1α), drive the reprogramming of genetic, transcriptional, and proteomic profiles. This leads to a spectrum of interconnected processes, including augmented survival of cancer cells, evasion of immune surveillance, metabolic reprogramming, remodeling of the extracellular matrix, and the development of resistance to conventional therapeutic modalities like radiotherapy and chemotherapy. Here, we summarize the latest research on the multifaceted effects of hypoxia, where a multitude of cellular and non-cellular elements crosstalk with each other and co-evolve in a synergistic manner. Additionally, we investigate therapeutic approaches targeting hypoxic niche, encompassing hypoxia-activated prodrugs, HIF inhibitors, nanomedicines, and combination therapies. Finally, we discuss some of the issues to be addressed and highlight the potential of emerging technologies in the treatment of cancer.