ROCK inhibitor reduces Myc-induced apoptosis and mediates immortalization of human keratinocytes

3-D tissue-engineered epidermis against human primary keratinocytes apoptosis via relieving mitochondrial oxidative stress in wound healing

The tissue-engineered epidermal (TEE), composed of biocompatible vectors and autogenous functional cells, is a novel strategy to solve the problem of shortage of donor skin sources. The human primary keratinocyte (HPK), the major skin components, are self-evident vital in wound healing and was considered as one of the preferred seed cells for TEEs. Since the process of separating HPKs from the skin triggers a stress state of the cells, achieving its rapid adhesion and proliferation on biomaterials remains challenging. The key to the clinical application is to ensure the normal function of cells while improving the proliferation ability in vitro, and to complete the complex mesenchymal epithelialization to achieve tissue remodeling after vivo implantation. Herein, in order to aid HPKs adhesion and proliferation in vitro and promoting wound healing, we developed a three dimensional collagen scaffold with Y-27632 sustainedly released from the nanoplatform, hollow mesoporous organosilica nanoparticles (HMON). The results showed that the porous structure within the TEE supports the implanted HPKs expanding in a three-dimensional mode to jointly construct the tissue-engineered epidermis in vitro and inhibited the mitochondria-mediated cell apoptosis. It was confirmed that the TEEs with suitable degradation rate could maintain drug release after implantation and could accelerate vascularization of wound base and further revealed the involvement of mesenchymal transformation of transplanted HPKs during skin regeneration in a nude mouse model with full-thickness skin resection. In conclusion, our study highlights the great potential of constructing TEE using a nanoparticle platform for the treatment of large-area skin defects.

ROCK Inhibitor (Y-27632) Abolishes the Negative Impacts of miR-155 in the Endometrium-Derived Extracellular Vesicles and Supports Embryo Attachment

Extracellular vesicles (EVs) are nanosized vesicles that act as snapshots of cellular components and mediate cellular communications, but they may contain cargo contents with undesired effects. We developed a model to improve the effects of endometrium-derived EVs (Endo-EVs) on the porcine embryo attachment in feeder-free culture conditions. Endo-EVs cargo contents were analyzed using conventional and real-time PCR for micro-RNAs, messenger RNAs, and proteomics. Porcine embryos were generated by parthenogenetic electric activation in feeder-free culture conditions supplemented with or without Endo-EVs. The cellular uptake of Endo-EVs was confirmed using the lipophilic dye PKH26. Endo-EVs cargo contained miR-100, miR-132, and miR-155, together with the mRNAs of porcine endogenous retrovirus (PERV) and β-catenin. Targeting PERV with CRISPR/Cas9 resulted in reduced expression of PERV mRNA transcripts and increased miR-155 in the Endo-EVs, and supplementing these in embryos reduced embryo attachment. Supplementing the medium containing Endo-EVs with miR-155 inhibitor significantly improved the embryo attachment with a few outgrowths, while supplementing with Rho-kinase inhibitor (RI, Y-27632) dramatically improved both embryo attachment and outgrowths. Moreover, the expression of miR-100, miR-132, and the mRNA transcripts of BCL2, zinc finger E-box-binding homeobox 1, β-catenin, interferon-γ, protein tyrosine phosphatase non-receptor type 1, PERV, and cyclin-dependent kinase 2 were all increased in embryos supplemented with Endo-EVs + RI compared to those in the control group. Endo-EVs + RI reduced apoptosis and increased the expression of OCT4 and CDX2 and the cell number of embryonic outgrowths. We examined the individual and combined effects of RI compared to those of the miR-155 mimic and found that RI can alleviate the negative effects of the miR-155 mimic on embryo attachment and outgrowths. EVs can improve embryo attachment and the unwanted effects of the de trop cargo contents (miR-155) can be alleviated through anti-apoptotic molecules such as the ROCK inhibitor.

ROCK ‘n TOR: An Outlook on Keratinocyte Stem Cell Expansion in Regenerative Medicine via Protein Kinase Inhibition

Keratinocyte stem cells play a fundamental role in homeostasis and repair of stratified epithelial tissues. Transplantation of cultured keratinocytes autografts provides a landmark example of successful cellular therapies by restoring durable integrity in stratified epithelia lost to devastating tissue conditions. Despite the overall success of such procedures, failures still occur in case of paucity of cultured stem cells in therapeutic grafts. Strategies aiming at a further amplification of stem cells during keratinocyte ex vivo expansion may thus extend the applicability of these treatments to subjects in which endogenous stem cells pools are depauperated by aging, trauma, or disease. Pharmacological targeting of stem cell signaling pathways is recently emerging as a powerful strategy for improving stem cell maintenance and/or amplification. Recent experimental data indicate that pharmacological inhibition of two prominent keratinocyte signaling pathways governed by apical mTOR and ROCK protein kinases favor stem cell maintenance and/or amplification ex vivo and may improve the effectiveness of stem cell-based therapeutic procedures. In this review, we highlight the pathophysiological roles of mTOR and ROCK in keratinocyte biology and evaluate existing pre-clinical data on the effects of their inhibition in epithelial stem cell expansion for transplantation purposes.

Rho Kinases in Embryonic Development and Stem Cell Research

The Rho-associated coiled-coil containing kinases (ROCKs or Rho kinases) belong to the AGC (PKA/PKG/PKC) family of serine/threonine kinases and are major downstream effectors of small GTPase RhoA, a key regulator of actin-cytoskeleton reorganization. The ROCK family contains two members, ROCK1 and ROCK2, which share 65% overall identity and 92% identity in kinase domain. ROCK1 and ROCK2 were assumed to be functionally redundant, based largely on their major common activators, their high degree kinase domain homology, and study results from overexpression with kinase constructs or chemical inhibitors. ROCK signaling research has expanded to all areas of biology and medicine since its discovery in 1996. The rapid advance is befitting ROCK’s versatile functions in modulating various cell behavior, such as contraction, adhesion, migration, proliferation, polarity, cytokinesis, and differentiation. The rapid advance is noticeably driven by an extensive linking with clinical medicine, including cardiovascular abnormalities, aberrant immune responsive, and cancer development and metastasis. The rapid advance during the past decade is further powered by novel biotechnologies including CRISPR-Cas and single cell omics. Current consensus, derived mainly from gene targeting and RNA interference approaches, is that the two ROCK isoforms have overlapping and distinct cellular, physiological and pathophysiology roles. In this review, we present an overview of the milestone discoveries in ROCK research. We then focus on the current understanding of ROCK signaling in embryonic development, current research status using knockout and knockin mouse models, and stem cell research.

RAS induced senescence of skin keratinocytes is mediated through Rho-associated protein kinase (ROCK)

Cellular senescence is a well-documented response to oncogene activation in many tissues. Multiple pathways are invoked to achieve senescence indicating its importance to counteract the transforming activities of oncogenic stimulation. We now report that the Rho-associated protein kinase (ROCK) signaling pathway is a critical regulator of oncogene-induced senescence in skin carcinogenesis. Transformation of mouse keratinocytes with oncogenic RAS upregulates ROCK activity and initiates a senescence response characterized by cell enlargement, growth inhibition, upregulation of senescence associated β-galactosidase (SAβgal) expression, and release of multiple pro-inflammatory factors comprising the senescence-associated secretory phenotype (SASP). The addition of the ROCK inhibitor Y-27632 and others prevents these senescence responses and maintains proliferating confluent RAS transformed keratinocyte cultures indefinitely. Mechanistically, oncogenic RAS transformation is associated with upregulation of cell cycle inhibitors p15Ink4b , p16Ink4a , and p19Arf and downregulation of p-AKT, all of which are reversed by Y-27632. RNA-seq analysis of Y-27632 treated RAS-transformed keratinocytes indicated that the inhibitor reduced growth-inhibitory gene expression profiles and maintained expression of proliferative pathways. Y-27632 also reduced the expression of NF-κB effector genes and the expression of IκBζ downstream mediators. The senescence inhibition from Y-27632 was reversible, and upon its removal, senescence reoccurred in vitro with rapid upregulation of cell cycle inhibitors, SASP expression, and cell detachment. Y-27632 treated cultured RAS-keratinocytes formed tumors in the absence of the inhibitor when placed in skin orthografts suggesting that factors in the tumor microenvironment can overcome the drive to senescence imparted by overactive ROCK activity.

Effect of Rho-Associated Protein Kinase Inhibitors on Epidermal Keratinocytes: A Proposed Application for Burn Wound Healing

Rho-associated protein kinases (ROCKs) affect a variety of cellular functions, including cell attachment, migration, and proliferation. ROCK inhibitors therefore have potential as tools for optimizing cell behavior in tissue engineering applications, including the manufacturing of cultivated epithelial autografts (CEAs) used in the treatment of burn patients. For example, ROCK inhibitors may facilitate earlier engraftment of CEA sheets by increasing the proliferation of skin keratinocytes ex vivo. Nevertheless, the current understanding of ROCK inhibitor action on epidermal keratinocytes is unclear owing to multiple drug formulations, drug concentrations, and cellular function assays having been used. The aim of this review article therefore is to identify consistent patterns of ROCK inhibitor action on human keratinocytes, as well as revealing key knowledge gaps. In doing so, we propose a clearer course of action for pursuing the potential benefits of ROCK inhibitors for the future treatment of burn patients. Impact statement The properties of Rho-associated protein kinase (ROCK) inhibitors are already used clinically within the fields of cardiology, neurology, and ophthalmology. These results encourage the broadening of ROCK inhibitor uses for other clinical applications. With respect to burn patients, ROCK inhibitors may facilitate improvements in patient survival and healing by reducing the time required for generating cultivated epithelial autograft (CEA) sheets from patient biopsies. Nevertheless, varying approaches to studying the effects of ROCK inhibitors on skin cells in vitro have complicated the development of improved protocols. Our review aims to clarify a diverse and growing body of literature as to the potential benefits for burn patients.

Immortalization and Characterization of Rat Lingual Keratinocytes in a High-Calcium and Feeder-Free Culture System Using ROCK Inhibitor Y-27632

Cultured keratinocytes are desirable models for biological and medical studies. However, primary keratinocytes are difficult to maintain, and there has been little research on lingual keratinocyte culture. Here, we investigated the effect of Y-27632, a Rho kinase (ROCK) inhibitor, on the immortalization and characterization of cultured rat lingual keratinocyte (RLKs). Three Y-27632-supplemented media were screened for the cultivation of RLKs isolated from Sprague-Dawley rats. Phalloidin staining and TUNEL assay were applied to visualize cytoskeleton dynamics and cell apoptosis following Y-27632 removal. Label-free proteomics, RT-PCR, calcium imaging, and cytogenetic studies were conducted to characterize the cultured cells. Results showed that RLKs could be conditionally immortalized in a high-calcium medium in the absence of feeder cells, although they did not exhibit normal karyotypes. The removal of Y-27632 from the culture medium led to reversible cytoskeletal reorganization and nuclear enlargement without triggering apoptosis, and a total of 239 differentially expressed proteins were identified by proteomic analysis. Notably, RLKs derived from the non-taste epithelium expressed some molecular markers characteristic of taste bud cells, yet calcium imaging revealed that they rarely responded to tastants. Collectively, we established a high-calcium and feeder-free culture method for the long-term maintenance of RLKs. Our results shed some new light on the immortalization and differentiation of lingual keratinocytes.

Conditional reprogramming culture conditions facilitate growth of lower-grade glioma models

BACKGROUND

The conditional reprogramming cell culture method was developed to facilitate growth of senescence-prone normal and neoplastic epithelial cells, and involves co-culture with irradiated fibroblasts and the addition of a small molecule Rho kinase (ROCK) inhibitor. The aim of this study was to determine whether this approach would facilitate the culture of compact low-grade gliomas.

METHODS

We attempted to culture 4 pilocytic astrocytomas, 2 gangliogliomas, 2 myxopapillary ependymomas, 2 anaplastic gliomas, 2 difficult-to-classify low-grade neuroepithelial tumors, a desmoplastic infantile ganglioglioma, and an anaplastic pleomorphic xanthoastrocytoma using a modified conditional reprogramming cell culture approach.

RESULTS

Conditional reprogramming resulted in robust increases in growth for a majority of these tumors, with fibroblast conditioned media and ROCK inhibition both required. Switching cultures to standard serum containing media, or serum-free neurosphere conditions, with or without ROCK inhibition, resulted in decreased proliferation and induction of senescence markers. Rho kinase inhibition and conditioned media both promoted Akt and Erk1/2 activation. Several cultures, including one derived from a NF1-associated pilocytic astrocytoma (JHH-NF1-PA1) and one from a BRAF p.V600E mutant anaplastic pleomorphic xanthoastrocytoma (JHH-PXA1), exhibited growth sufficient for preclinical testing in vitro. In addition, JHH-NF1-PA1 cells survived and migrated in larval zebrafish orthotopic xenografts, while JHH-PXA1 formed orthotopic xenografts in mice histopathologically similar to the tumor from which it was derived.

CONCLUSIONS

These studies highlight the potential for the conditional reprogramming cell culture method to promote the growth of glial and glioneuronal tumors in vitro, in some cases enabling the establishment of long-term culture and in vivo models.

An overview of neuroblastoma cell lineage phenotypes and in vitro models

This review was conducted to present the main neuroblastoma (NB) clinical characteristics and the most common genetic alterations present in these pediatric tumors, highlighting their impact in tumor cell aggressiveness behavior, including metastatic development and treatment resistance, and patients' prognosis. The distinct three NB cell lineage phenotypes, S-type, N-type, and I-type, which are characterized by unique cell surface markers and gene expression patterns, are also reviewed. Finally, an overview of the most used NB cell lines currently available for in vitro studies and their unique cellular and molecular characteristics, which should be taken into account for the selection of the most appropriate model for NB pre-clinical studies, is presented. These valuable models can be complemented by the generation of NB reprogrammed tumor cells or organoids, derived directly from patients' tumor specimens, in the direction toward personalized medicine.

Conditional reprogramming: next generation cell culture

Long-term primary culture of mammalian cells has been always difficult due to unavoidable senescence. Conventional methods for generating immortalized cell lines usually require manipulation of genome which leads to change of important biological and genetic characteristics. Recently, conditional reprogramming (CR) emerges as a novel next generation tool for long-term culture of primary epithelium cells derived from almost all origins without alteration of genetic background of primary cells. CR co-cultures primary cells with inactivated mouse 3T3-J2 fibroblasts in the presence of RHO-related protein kinase (ROCK) inhibitor Y-27632, enabling primary cells to acquire stem-like characteristics while retain their ability to fully differentiate. With only a few years' development, CR shows broad prospects in applications in varied areas including disease modeling, regenerative medicine, drug evaluation, drug discovery as well as precision medicine. This review is thus to comprehensively summarize and assess current progress in understanding mechanism of CR and its wide applications, highlighting the value of CR in both basic and translational researches and discussing the challenges faced with CR.

Culture and application of conditionally reprogrammed primary tumor cells

Cancer is still a major public-health problem that threatens human life worldwide and further study needs to be carried out in the basic and preclinical areas. Although high-throughput sequencing technology and individualized precise therapy have made breakthroughs over the years, the high failure rate of clinical translational research has limited the innovation of antitumor drugs and triggered the urgent need for optimal cancer-research models. The development of cancerous cell lines, patient-derived xenograft (PDX) models, and organoid has strongly promoted the development of tumor-biology research, but the prediction values are limited. Conditional reprogramming (CR) is a novel cell-culture method for cancer research combining feeder cells with a Rho-associated coiled-coil kinase (ROCK) inhibitor, which enables the rapid and continuous proliferation of primary epithelial cells. In this review, we summarize the methodology to establish CR model and overview recent functions and applications of CR cell-culture models in cancer research with regard to the study of cancer-biology characterization, the exploration of therapeutic targets, individualized drug screening, the illumination of mechanisms about response to antitumor drugs, and the improvement of patient-derived animal models, and finally discuss in detail the major limitations of this cell-culture system.

Conditional reprogramming: Modeling urological cancer and translation to clinics

Patient-derived models, including cell models (organoids and conditionally reprogrammed cells [CRCs]) and patient-derived xenografts, are urgently needed for both basic and translational cancer research. Conditional reprogramming (CR) technique refers to a co-culture system of primary human normal or tumor cells with irradiated murine fibroblasts in the presence of a Rho-associated kinase inhibitor to allow the primary cells to acquire stem cell properties and the ability to proliferate indefinitely in vitro without any exogenous gene or viral transfection. Considering its robust features, the CR technique may facilitate cancer research in many aspects. Under in vitro culturing, malignant CRCs can share certain genetic aberrations and tumor phenotypes with their parental specimens. Thus, tumor CRCs can promisingly be utilized for the study of cancer biology, the discovery of novel therapies, and the promotion of precision medicine. For normal CRCs, the characteristics of normal karyotype maintenance and lineage commitment suggest their potential in toxicity testing and regenerative medicine. In this review, we discuss the applications, limitations, and future potential of CRCs in modeling urological cancer and translation to clinics.

Efficient correction of a deleterious point mutation in primary horse fibroblasts with CRISPR-Cas9

Phenotypic selection during animal domestication has resulted in unwanted incorporation of deleterious mutations. In horses, the autosomal recessive condition known as Glycogen Branching Enzyme Deficiency (GBED) is the result of one of these deleterious mutations (102C > A), in the first exon of the GBE1 gene (GBE1102C>A). With recent advances in genome editing, this type of genetic mutation can be precisely repaired. In this study, we used the RNA-guided nuclease CRISPR-Cas9 (clustered regularly-interspaced short palindromic repeats/CRISPR-associated protein 9) to correct the GBE1102C>A mutation in a primary fibroblast cell line derived from a high genetic merit heterozygous stallion. To correct this mutation by homologous recombination (HR), we designed a series of single guide RNAs (sgRNAs) flanking the mutation and provided different single-stranded donor DNA templates. The distance between the Cas9-mediated double-stranded break (DSB) to the mutation site, rather than DSB efficiency, was the primary determinant for successful HR. This framework can be used for targeting other harmful diseases in animal populations.

Murine neuroblastoma cell lines developed by conditional reprogramming preserve heterogeneous phenotypes observed in vivo

Neuroblastoma (NB) is a pediatric tumor of the peripheral nervous system. Treatment of the disease represents an unsolved clinical problem, as survival of patients with aggressive form of NB remains below 50%. Despite recent identification of numerous potential therapeutic targets, clinical trials validating them are challenging due to the rarity of the disease and its high patient-to-patient heterogeneity. Hence, there is a need for the accurate preclinical models that would allow testing novel therapeutic approaches and prioritizing the clinical studies, preferentially in personalized way. Here, we propose using conditional reprogramming (CR) technology for rapid development of primary NB cell cultures that could become a new model for such tests. This newly established method allowed for indefinite propagation of normal and tumor cells of epithelial origin in an undifferentiated state by their culture in the presence of Rho-associated kinase (ROCK) inhibitor, Y-27632, and irradiated mouse feeder cells. Using a modification of this approach, we isolated cell lines from tumors arising in the TH-MYCN murine transgenic model of NB (CR-NB). The cells were positive for neuronal markers, including Phox2B and peripherin and consisted of two distinct populations: mesenchymal and adrenergic expressing corresponding markers of their specific lineage. This heterogeneity of the CR-NB cells mimicked the different tumor cell phenotypes in TH-MYCN tumor tissues. The CR-NB cells preserved anchorage-independent growth capability and were successfully passaged, frozen and biobanked. Further studies are required to determine the utility of this method for isolation of human NB cultures, which can become a novel model for basic, translational, and clinical research, including individualized drug testing.

Improved Generation of Induced Pluripotent Stem Cells From Hair Derived Keratinocytes - A Tool to Study Neurodevelopmental Disorders as ADHD

In the last decade, there is an increasing application of induced pluripotent stem cells (iPSCs) for disease modeling. The iPSC technology enables the study of patient-specific neuronal cell lines in vitro to evaluate dysfunction at the cellular level and identify the responsible genetic factors. This approach might be particularly valuable for filling the gap of knowledge at the cellular and molecular levels underlying the pathophysiology of various neurodevelopmental and/or psychiatric disorders, such as attention-deficit hyperactivity disorder (ADHD). However, the invasiveness of skin biopsy or blood withdrawal might represent a major impediment in such protected population. Using hair derived keratinocytes as starting somatic cells circumvents this problem as sample collections can be performed non-invasively. Here we describe an improved, convenient, standardized and effective method to culture and reprogram hair derived keratinocytes from three healthy controls and one ADHD patient into iPSCs, which in turn will be used to generate differentiated neuronal cells. All the cell types were maintained in highly defined, serum-free conditions and showed expression of the respective key marker genes, assessed by both immunocytochemistry and qRT-PCR. The described in vitro personalized neuronal model has its advantage in modeling neurodevelopmental trajectories since it can recapitulate key processes of brain development at the cellular and molecular level and is intended to be used as for example studying ADHD etiopathology.

Establishment of a nasopharyngeal carcinoma cell line capable of undergoing lytic Epstein-Barr virus reactivation

Epstein-Barr virus (EBV) infects more than 90% of the adult human population. Undifferentiated nasopharyngeal carcinoma (NPC) is common in Southeast Asia, with a particularly high incidence among southern Chinese. The EBV genome can be detected in practically all cancer cells in undifferentiated NPC. The role of EBV in pathogenesis of undifferentiated NPC remains elusive. NPC cell lines are known to be difficult to establish in culture. The EBV+ve NPC cell lines, even if established in culture, rapidly lost their EBV episomes upon prolonged propagation. At present, the C666-1 NPC cell line, which is defective in lytic EBV reactivation, is the only EBV+ve NPC cell line available for NPC and EBV research. The need to establish new and representative NPC cell lines is eminent for NPC and EBV research. In this study, we report the use of the Rho-associated kinase inhibitor (Y-27632) has facilitated the establishment of a new EBV+ve NPC cell line from an earlier established NPC xenograft, C17. The C17 cell line was tumorigenic in immune-deficient mice (NOD/SCID). It retained the EBV episomes and could be induced to undergo productive lytic reactivation of EBV to generate infectious virus particles. The C17 cell line represents a new investigative tool for NPC and EBV studies. The ability of C17 to undergo lytic reactivation is unique and opens up the opportunity to examine regulation of latent and lytic infection of EBV and their contributions to NPC pathogenesis.

Long-term expansion of primary equine keratinocytes that maintain the ability to differentiate into stratified epidermis

BACKGROUND

Skin injuries in horses frequently lead to chronic wounds that lack a keratinocyte cover essential for healing. The limited proliferation of equine keratinocytes using current protocols has limited their use for regenerative medicine. Previously, equine induced pluripotent stem cells (eiPSCs) have been produced, and eiPSCs could be differentiated into equine keratinocytes suitable for stem cell-based skin constructs. However, the procedure is technically challenging and time-consuming. The present study was designed to evaluate whether conditional reprogramming (CR) could expand primary equine keratinocytes rapidly in an undifferentiated state but retain their ability to differentiate normally and form stratified epithelium.

METHODS

Conditional reprogramming was used to isolate and propagate two equine keratinocyte cultures. PCR and FISH were employed to evaluate the equine origin of the cells and karyotyping to perform a chromosomal count. FACS analysis and immunofluorescence were used to determine the purity of equine keratinocytes and their proliferative state. Three-dimensional air-liquid interphase method was used to test the ability of cells to differentiate and form stratified squamous epithelium.

RESULTS

Conditional reprogramming was an efficient method to isolate and propagate two equine keratinocyte cultures. Cells were propagated at the rate of 2.39 days/doubling for more than 40 population doublings. A feeder-free culture method was also developed for long-term expansion. Rock-inhibitor is critical for both feeder and feeder-free conditions and for maintaining the proliferating cells in a stem-like state. PCR and FISH validated equine-specific markers in the cultures. Karyotyping showed normal equine 64, XY chromosomes. FACS using pan-cytokeratin antibodies showed a pure population of keratinocytes. When ROCK inhibitor was withdrawn and the cells were transferred to a three-dimensional air-liquid culture, they formed a well-differentiated stratified squamous epithelium, which was positive for terminal differentiation markers.

CONCLUSIONS

Our results prove that conditional reprogramming is the first method that allows for the rapid and continued in vitro propagation of primary equine keratinocytes. These unlimited supplies of autologous cells could be used to generate transplants without the risk of immune rejection. This offers the opportunity for treating recalcitrant horse wounds using autologous transplantation.

Nucleoside diphosphate kinase B promotes osteosarcoma proliferation through c-Myc

Osteosarcoma (OS) is one of the most common primary bone tumors and has a high disablity rate and case-fatality rate. The protracted stagnancy of the chemotherapy program and surgical technology for OS treatment prompted us to focus on the mechanisms of cancer carcinogenesis progression in OS. Nucleoside diphosphate kinase B (NME2) is a type of nucleoside diphosphate kinase that plays an important role in cellular processes. In this study, we report overexpression of NME2 in OS cell lines and correlate this overexpression with the clinicopathologic features of osteosarcoma. We used si-NME2 to downregulate expression of NME2 in OS cell lines. The results of the CCK8 and clone forming assays show that NME2 promotes OS cell line proliferation. Western blot assays show that deregulation of NME2 results in enhanced the expression of c-Myc, which promotes OS proliferation.

Human foreskin fibroblasts: from waste bag to important biomedical applications

Circumcision is one of the most performed surgical procedures worldwide, and it is estimated that one in three men worldwide is circumcised, which makes the preputial skin removed after surgery an abundant material for possible applications. In particular, it is possible efficiently to isolate the cells of the foreskin, with fibroblasts being the most abundant cells of the dermis and the most used in biomedical research. This work aimed to review the knowledge and obtain a broad view of the main applications of human foreskin fibroblast cell culture. A literature search was conducted, including clinical trials, preclinical basic research studies, reviews and experimental studies. Several medical and laboratory applications of human foreskin fibroblast cell culture have been described, especially when it comes to the use of human foreskin fibroblasts as feeder cells for the cultivation of human embryonic stem cells, in addition to co-culture with other cell types. The culture of foreskin fibroblasts has also been used to: obtain induced pluripotent stem cells; the diagnosis of Clostridium difficile; to test the toxicity and effect of substances on normal cells, especially the toxicity of possible antineoplastic drugs; in viral culture, mainly of the human cytomegalovirus, study of the pathogenesis of other microorganisms; varied studies of cellular physiology and cellular interactions. Fibroblasts are important for cell models for varied application cultures, demonstrating how the preputial material can be reused, making possible new applications.

Level of evidence: Not applicable for this multicentre audit.

Rho-kinase inhibitor Y-27632 facilitates the proliferation, migration and pluripotency of human periodontal ligament stem cells

The selective in vitro expansion and differentiation of multipotent stem cells are critical steps in cell-based regenerative therapies, while technical challenges have limited cell yield and thus affected the success of these potential treatments. The Rho GTPases and downstream Rho kinases are central regulators of cytoskeletal dynamics during cell cycle and determine the balance between stem cells self-renewal, lineage commitment and apoptosis. Trans-4-[(1R)-aminoethyl]-N-(4-pyridinyl)cylohexanecarboxamidedihydrochloride (Y-27632), Rho-associated kinase (ROCK) inhibitor, involves various cellular functions that include actin cytoskeleton organization, cell adhesion, cell motility and anti-apoptosis. Here, human periodontal ligament stem cells (PDLSCs) were isolated by limiting dilution method. Cell counting kit-8 (CCK8), 5-ethynyl-2'-deoxyuridine (EdU) labelling assay, cell apoptosis assay, cell migration assay, wound-healing assay, alkaline phosphatase (ALP) activity assay, Alizarin Red S staining, Oil Red O staining, quantitative real-time polymerase chain reaction (qRT-PCR) were used to determine the effects of Y-27632 on the proliferation, apoptosis, migration, stemness, osteogenic and adipogenic differentiation of PDLSCs. Afterwards, Western blot analysis was performed to elucidate the mechanism of cell proliferation. The results indicated that Y-27632 significantly promoted cell proliferation, chemotaxis, wound healing, fat droplets formation and pluripotency, while inhibited ALP activity and mineral deposition. Furthermore, Y-27632 induced PDLSCs proliferation through extracellular-signal-regulated kinase (ERK) signalling cascade. Therefore, control of Rho-kinase activity may enhance the efficiency of stem cell-based treatments for periodontal diseases and the strategy may have the potential to promote periodontal tissue regeneration by facilitating the chemotaxis of PDLSCs to the injured site, and then enhancing the proliferation of these cells and maintaining their pluripotency.

Small Molecule Supplements Improve Cultured Megakaryocyte Polyploidization by Modulating Multiple Cell Cycle Regulators

Platelets (PLTs) are produced by megakaryocytes (MKs) that completed differentiation and endomitosis. Endomitosis is an important process in which the cell replicates its DNA without cytokinesis and develops highly polyploid MK. In this study, to gain a better PLTs production, four small molecules (Rho-Rock inhibitor (RRI), nicotinamide (NIC), Src inhibitor (SI), and Aurora B inhibitor (ABI)) and their combinations were surveyed as MK culture supplements for promoting polyploidization. Three leukemia cell lines as well as primary mononuclear cells were chosen in the function and mechanism studies of the small molecules. In an optimal culture method, cells were treated with different small molecules and their combinations. The impact of the small molecules on megakaryocytic surface marker expression, polyploidy, proliferation, and apoptosis was examined for the best MK polyploidization supplement. The elaborate analysis confirmed that the combination of SI and RRI together with our MK induction system might result in efficient ploidy promotion. Our experiments demonstrated that, besides direct downregulation on the expression of cytoskeleton protein actin, SI and RRI could significantly enhance the level of cyclins through the suppression of p53 and p21. The verified small molecule combination might be further used in the in vitro PLT manufacture and clinical applications.

Genomic comparison of early-passage conditionally reprogrammed breast cancer cells to their corresponding primary tumors

Conditionally reprogrammed cells (CRCs) are epithelial cells that are directly isolated from patients' specimens and propagated in vitro with feeder cells and a Rho kinase inhibitor. A number of these cells have been generated from biopsies of breast cancer patients, including ductal carcinoma in situ and invasive carcinomas. The characterization of their genomic signatures is essential to determine their ability to reflect the natural biology of their tumors of origin. In this study, we performed the genomic characterization of six newly established invasive breast cancer CRC cultures in comparison to the original patients' primary breast tumors (PBT) from which they derived. The CRCs and corresponding PBTs were simultaneously profiled by genome-wide array-CGH, targeted next generation sequencing and global miRNA expression to determine their molecular similarities in the patterns of copy number alterations (CNAs), gene mutations and miRNA expression levels, respectively. The CRCs' epithelial cells content and ploidy levels were also evaluated by flow cytometry. A similar level of CNAs was observed in the pairs of CRCs/PBTs analyzed by array-CGH, with >95% of overlap for the most frequently affected cytobands. Consistently, targeted next generation sequencing analysis showed the retention of specific somatic variants in the CRCs as present in their original PBTs. Global miRNA profiling closely clustered the CRCs with their PBTs (Pearson Correlation, ANOVA paired test, P<0.05), indicating also similarity at the miRNA expression level; the retention of tumor-specific alterations in a subset of miRNAs in the CRCs was further confirmed by qRT-PCR. These data demonstrated that the human breast cancer CRCs of this study maintained at early passages the overall copy number, gene mutations and miRNA expression patterns of their original tumors. The further characterization of these cells by other molecular and cellular phenotypes at late cell passages, are required to further expand their use as a unique and representative ex-vivo tumor model for basic science and translational breast cancer studies.

DlgR2 knockdown boosts dendritic cell activity and inhibits hepatocellular carcinoma tumor in-situ growth

Tumor-specific hepatic stellate cells (tHSCs) positively participate in human hepatocellular carcinoma (HCC) tumorigenesis and progression. Our previous studies have shown that tHSCs co-culture with dendritic cells (DCs) induced DIgR2 (dendritic cell-derived immunoglobulin receptor 2) expression. The latter is a member of IgSF inhibitory receptor suppressing DCs-initiated antigen-specific T-cell responses. In the current study, we show that hepatic artery injection of DlgR2 siRNA significantly inhibited in-situ HCC xenograft growth in rat livers. Further, 5-FU-medied inhibition of in-situ HCC growth was dramatically sensitized with DlgR2 silence. DlgR2 siRNA injection indeed downregulated DlgR2 in ex-vivo cultured tumor-derived DCs (tDCs). More importantly, tDCs activity was boosted following DlgR2 siRNA. These cells presented with upregulated CD80, CD86 and MHC-II. Production of interleukin-12 and tumor necrosis factor-α was also increased in the DlgR2-silenced tDCs. We propose that DlgR2 knockdown likely boosts the activity of tumor-associated DCs, and inhibits growth of in-situ HCC xenografts.

Tumor-specific hepatic stellate cells (tHSCs) induces DIgR2 expression in dendritic cells to inhibit T cells

Tumor-specific hepatic stellate cells (tHSCs) contributes to tumorigenesis and progression of hepatocellular carcinoma (HCC). The potential function of tHSCs on dendritic cells (DCs) was studied here. We discovered that tHSCs co-culture induced upregulation of DIgR2 (dendritic cell-derived immunoglobulin receptor 2) in bone marrow-derived DCs (mDCs). Activation of MEK-ERK is required for DIgR2 expression in mDCs. MEK-ERK inhibitors or shRNA-mediated silence of MEK1/2 in mDCs inhibited tHSCs-induced DIgR2 expression. Meanwhile, tHSCs stimulation decreased production of multiple cytokines (CD80, CD86 and IL-12) in mDCs. Such an effect was almost reversed by DIgR2 shRNA in mDCs. Further, tHSCs-stimulated mDCs induced T-cell hypo-responsiveness, leading to decreased cytotoxic T lymphocyte (CTL) activity and reduced IFN-γ production in splenic T cells. T cell proliferation inhibition and apoptosis were also noticed. These actions on T cells were again largely inhibited by DIgR2 shRNA in mDCs. Together, our results indicate that tHSCs directly induces DIgR2 expression in DCs to inhibit T cells.