Efficient DNA Walker Guided with Well-Regulated Interfacial Tracks for Ultrasensitive Electrochemiluminescence Biosensing.

Herein, highly efficient deoxyribonucleic acid (DNA) walking on electrode surfaces was realized by regulating DNA tracks, which was applied to construct an ultrasensitive electrochemiluminescent (ECL) biosensor for BCR/ABL fusion gene detection. The well-regulated DNA tracks were constructed via supersandwich hybridization chain reaction of two DNA strands (L1 and L2) to generate periodic linear dsDNA concatemers, where an exposed L1 domain closed with blocking strands (BS). The prepared DNA tracks were further assembled onto the surface of the Au nanoparticle-functionalized g-C3N4 nanohybrid (Au@g-C3N4 NHs)-modified electrode, achieving well-regulated interfacial tracks for the DNA walker. On this state, folic acid-labeled BS (FA-BS) were close to Au@g-C3N4 NHs, performing a quenched ECL emission. With existence of the BCR/ABL fusion gene, the target combined two walking DNA strands (WD1 and WD2) to form the bipedal DNA walkers, which walked on the well-regulated interfacial DNA tracks and replaced the FA-BS to light up the ECL emission, realizing DNA walker-based signal amplification. Compared to randomly constructed DNA tracks, the well-regulated DNA tracks reduced the kinetics barrier and fitted the step size of the DNA walker, thus promoting the DNA walking efficiency and decreasing the risk of interruption in the walking process. As a result, the designed DNA walker presented higher efficiency and capacity in signal amplification. Benefiting from this efficient DNA walker strategy, the ECL biosensor achieved sensitive detection of the BCR/ABL fusion gene with a detection limit of 0.18 fM. This smart strategy proposed a brief strategy to promote the working efficiency of the biosensor, which presented great application potential in clinical molecular diagnosis.

A novel electrochemical biosensor based on peptidoglycan and platinum-nickel-copper nano-cube for rapid detection of Gram-positive bacteria.

A novel non-enzyme electrochemical biosensor for the rapid detection of Gram-positive bacteria has been constructed that relys on a stable and efficient combination between the peptidoglycan layer and platinum-nickel-copper nanocubes (Pt-Ni-Cu NCs). Briefly, bacteria were first captured by a specific antibody. Then, the electrochemical signal materials (Pt-Ni-Cu NCs) were bound to the bacteria peptidoglycan layer using specific structural and surface features. The rapid and sensitive bacterial detection was then achieved using intrinsic electrochemical characteristics and superoxidase-like activity of the Pt-Ni-Cu NCs. Moreover, the nature of peptidoglycan covering the whole bacteria provided the premise for signal amplification. Under optimal conditions, the electrochemical signal variation was proportional to the concentration of bacteria ranging from 1.5 × 102 to 1.5 × 108 CFU/mL with a detection limit of 42 CFU/mL using a working potential of - 0.4 V. This electrochemical biosensor has been successfully applied to detect bacteria concentrations in urine samples, and the recoveries range from 90.4 to 107%. The proposed biosensor could be applied for broad-spectrum detection of Gram-positive bacteria since most Gram-positive bacteria possess a thick peptidoglycan layer. The developed electrochemical biosensing strategy might be used as a potential tool for clinical pathogenic bacteria detection and point-of-care testing (POCT).

An ER-Horse Detonating Stress Cascade for Hepatocellular Carcinoma Nanotherapy.

Persisting and excessive endoplasmic reticulum stress (ERS) can evoke rapid cell apoptosis. Therapeutic interference of ERS signaling holds enormous potential for cancer nanotherapy. Herein, a hepatocellular carcinoma (HCC) cell-derived ER vesicle (ERV) encapsulating siGRP94, denoted as ER-horse, has been developed for precise HCC nanotherapy. Briefly, ER-horse, like the Trojan horse, was recognized via homotypic camouflage, imitated the physiological function of ER, and exogenously opened the Ca2+ channel. Consequently, the mandatory pouring-in of extracellular Ca2+ triggered the aggravated stress cascade (ERS and oxidative stress) and apoptosis pathway with the inhibition of unfolded protein response by siGRP94. Collectively, our findings provide a paradigm for potent HCC nanotherapy via ERS signaling interference and exploring therapeutic interference of physiological signal transduction pathways for precision cancer therapy.

Hierarchical self-uncloaking CRISPR-Cas13a-customized RNA nanococoons for spatial-controlled genome editing and precise cancer therapy.

CRISPR-Cas13a holds enormous potential for developing precise RNA editing. However, spatial manipulation of CRISPR-Cas13a activity remains a daunting challenge for elaborately regulating localized RNase function. Here, we designed hierarchical self-uncloaking CRISPR-Cas13a-customized RNA nanococoons (RNCOs-D), featuring tumor-specific recognition and spatial-controlled activation of Cas13a, for precise cancer synergistic therapy. RNCOs-D consists of programmable RNA nanosponges (RNSs) capable of targeted delivery and caging chemotherapeutic drug, and nanocapsules (NCs) anchored on RNSs for cloaking Cas13a/crRNA ribonucleoprotein (Cas13a RNP) activity. The acidic endo/lysosomal microenvironment stimulates the outer decomposition of NCs with concomitant Cas13a RNP activity revitalization, while the inner disassembly through trans-cleavage of RNSs initiated by cis-recognition and cleavage of EGFR variant III (EGFRvIII) mRNA. RNCOs-D demonstrates the effective EGFRvIII mRNA silencing for synergistic therapy of glioblastoma cancer cells in vitro and in vivo. The engineering of RNSs, together with efficient Cas13a activity regulation, holds immense prospect for multimodal and synergistic cancer therapy.

Corrigendum to "Identification and characterization of the cellular subclones that contribute to the pathogenesis of mantle cell lymphoma" [Genes Dis 6(4) 2019 407-418].

[This corrects the article DOI: 10.1016/j.gendis.2018.12.002.].

Eco-Friendly Preparation of Epoxy-Rich Graphene Oxide for Wound Healing.

Despite the ever-growing endangerment caused by the multidrug resistance (MDR) of bacteria, the development of effective antibacterial materials still remains a global challenge. Current antibiotic therapies cannot simultaneously inactivate bacteria and accelerate wound healing. This study aimed to originally separate the intercalation of MnO3+ and the oxidation processes to synthesize epoxy-rich graphene oxide (erGO) nanofilms via an eco-friendly synthetic route, which possessed low density and large lamellar distribution and was rich in epoxide. Importantly, the MnO3+ could be separated from the product and recycled for preparing the next generation of erGO nanofilms, which was quite economical and eco-friendly. The erGO nanofilm was capable of successfully inhibiting Gram-negative bacteria and even had excellent growth-inhibitory effects on Gram-positive bacteria including multidrug resistance (MDR) bacteria, as evidenced by antibacterial phenomena. Additionally, the erGO nanofilm with high •C density formed from epoxide exerted excellent antibacterial effects through tight membrane wrapping and induction of lipid peroxidation. The wound-healing property of the erGO nanofilm was evaluated via treatments of wounds infected by Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), which not only killed bacteria but also accelerated wound healing in mice with a skin infection. The novel erGO nanofilm with dual antimicrobial mechanisms might serve as a promising multifunctional antimicrobial agent for medical wound dressing with high biocompatibility.

Prevalence of depression and anxiety and correlations between depression, anxiety, family functioning, social support and coping styles among Chinese medical students.

BACKGROUND: Medical students experience depression and anxiety at a higher rate than the general population or students from other specialties. While there is a growing literature on the high prevalence of depression and anxiety symptoms and about potential risk factors to the prevalence of depression and anxiety symptoms among medical students, there is a paucity of evidence focused on the prevalence of depression and anxiety symptoms and associations with family function, social support and coping styles in Chinese vocational medicine students. This study aims to investigate the prevalence of depression and anxiety symptoms among Chinese medical students and assess the correlation between depression/anxiety symptoms and family function, social support and coping styles. METHODS: A sample of 2057 medical students from Chongqing Medical and Pharmaceutical College in China was investigated with a self-report questionnaire, which included demographic information, Zung self-rating depression scale, Zung Self-Rating Anxiety Scale, Family APGAR Index, Social Support Rating Scale and Trait Coping Style Questionnaire. RESULTS: The prevalence of depression and anxiety symptoms among the medical students was 57.5 and 30.8%, respectively. Older students(≥20 years) experienced higher levels of depression and anxiety. More depression and anxiety symptoms were exhibited among students with big financial burden, big study-induced stress and poor sleep quality. Students with large employment pressure showed more anxiety symptoms. Students who live alone or had bad relationship with their lovers or classmates or friends showed higher depression and anxiety scores. Depression and anxiety symptoms had highly significant correlations with family functioning, social support and coping style. CONCLUSIONS: Academic staffs should take measures to reduce depression and anxiety among medical students and to provide educational counseling and psychological support for students to cope with these problems.

Transcriptional Activation of Gstp1 by MEK/ERK Signaling Confers Chemo-Resistance to Cisplatin in Lung Cancer Stem Cells.

Lung cancer management remains a challenge due to its asymptomatic and late presentation when it is metastatic. The clinical response to the first-line platinum-based chemotherapy in patients with advanced lung cancer is disappointing due to the development of chemoresistance. Chemoresistance is a complex phenomenon. Mechanistic research using experimental models has yielded limited clinical results to help increase understanding for overcoming resistance. While the role of lung CSCs in conferring multidrug resistance has been postulated, experimental evidence remains associative and lacks in depth mechanistic inquisition. In the present study, using mouse and human lung adenocarcinoma cell lines and their respective paired CSC derivative cell lines that we generated, we identified cancer stem cell component of lung adenocarcinoma as the source that confers multidrug resistance phenotype. Mechanistically, Gstp1 confers cisplatin resistance in mouse and human lung CSC models, both in vitro and in vivo. Further, transcriptional activation of Gstp1 expression by MEK/ERK signaling underlies cisplatin resistance in lung CSC cells. Moreover, we show that GSTP1 expression is a poor diagnostic and prognostic marker for human lung adenocarcinoma, thus is of high clinical relevance. Taken together, we have provided mechanistic understanding of the lung CSC in mediating chemoresistance.

Nr5a2 promotes cancer stem cell properties and tumorigenesis in nonsmall cell lung cancer by regulating Nanog.

Lung cancer has the highest mortality rate due to late diagnosis and high incidence of metastasis. Cancer stem cells (CSCs) are a subgroup of cancer cells with self-renewal capability similar to that of normal stem cells (NSCs). While CSCs may play an important role in cancer progression, mechanisms underlying CSC self-renewal and the relationship between self-renewal of the NSCs and CSCs remain elusive. The orphan nuclear receptor Nr5a2 is a transcriptional factor, and a regulator of stemness of embryonic stem cells and induced pluripotent stem cells. However, whether Nr5a2 regulates the self-renewal of lung CSCs is unknown. Here, we showed the diagnostic and prognostic values of elevated Nr5a2 expression in human lung cancer. We generated the mouse LLC-SD lung carcinoma CSC cellular model in which Nr5a2 expression was enhanced. Using the LLC-SD model, through transient and stable siRNA interference of Nr5a2 expression, we provided convincing evidence for a regulatory role of Nr5a2 in the maintenance of lung CSC self-renewal and stem cell properties in vitro. Further, using the syngeneic and orthotopic lung transplantation model, we elucidated augmented cancer biological properties associated with Nr5a2 promotion of LLC-SD self-renewal. More importantly, we revealed that Nr5a2's regulatory role in promoting LLC-SD self-renewal is mediated by transcriptional activation of its direct target Nanog. Taken together, in this study, we have provided convincing evidence in vitro and in vivo demonstrating that Nr5a2 can induce lung CSC properties and promote tumorigenesis and progression through transcriptional up-regulation of Nanog.

Identification and characterization of the cellular subclones that contribute to the pathogenesis of mantle cell lymphoma.

Mantle cell lymphoma (MCL) is a B-cell malignancy with poor clinical outcome and undefined pathogenesis. Development of clinically relevant cellular models for MCL research is an urgent need. Our preliminary observations lead the development of two novel hypotheses that we tested in this study: 1. multicellular spheroid might be a unique growth mode of early-stage cells in MCL; 2. MCL might be a polyclonal tumor. We made the following original observations that have not been reported: First, we have provided a new experiment method for enriching MCL early-stage cells and characterized the spheroid mode of growth as a unique feature of early-stage MCL cells in cell line as well as in clinical samples. Second, we have established a clinically relevant cellular model of MCL, the JeKo-1-spheroid cell line, that was highly enriched in early-stage sub-clones. JeKo-1-spheroid cells and the spheroid growing cells enriched from MCL patients exhibited comparably enhanced tumorigenic abilities and similar biological features. Third, Immunophenotypic analysis has revealed that MCL may be derived from precursor-B(pre-B), immature-B and mature-B cells, not only the mature-B cells as WHO classified in 2016. Fourth, MCL may be a polyclonal disease composed of CD19-/IgM-, CD19-/IgM+, CD19+/IgM+ three sub-clones, of which the CD19-/IgM+ sub-clone might be the dominant sub-clone with the strongest tumorigenic ability. Fifth, CD19+/IgM- that differentiates MCL and normal B cells may represent a new marker for MCL early detection, minor residual disease monitoring after therapies and prognosis.

NFATC2 is a novel therapeutic target for colorectal cancer stem cells.

BACKGROUND: Colorectal cancer stem cells (CRC-SCs) contribute to the initiation and progression of colorectal cancer (CRC). However, the underlying mechanisms for the propagation of CRC-SCs have remained elusive. PURPOSE: The objective of this study was to study the role of NFATC2 in maintenance of the stemness in CRC-SCs. METHOD: The expression levels of mRNA and protein were determined by qRT-PCR and western-blot, respectively. CRC-SCs were isolated by spheroid formation assay and flowcytometry. The sphere-forming and self-renewal abilities of CRC-SCs were determined by spheroid formation assay. The tumorigenicity of CRC-SCs was determined by cell-derived xenograft model. Gene manipulation was performed by lentivirus-mediated delivery system. RESULTS: We first found that NFATC2 is upregulated in primary CRC-SCs. Overexpression of NFATC2 promotes self-renewal and the expression of stem cell markers of CRC-SCs. Conversely, knockdown of NFATC2 attenuates stem cell-like properties of CRC-SCs. Mechanistic analysis indicated that NFATC2 upregulates the expression of AJUBA, downregulates the phosphorylation level of YAP, and therefore activates the transcriptional activities of YAP and promotes the stemness of CRC-SCs. CONCLUSION: Our findings demonstrate NFATC2 as an oncogene that can promote the stemness of CRC-SCs. This work suggests a novel therapeutic strategy against CRC caused by aberrant expression of NFATC2.

Neuralized1a regulates asymmetric division in mouse Lewis lung carcinoma cells.

Asymmetric division (ASD), the unique characteristic of normal stem cells, is regarded as a stemness marker when applied to the study of cancer stem cells (CSCs). However, the role of ASD in the self-renewal of CSCs and its regulation remain largely unknown. Here, we first established a mouse Lewis lung carcinoma CSC cell line that could undergo asymmetric division (LLC-ASD cells) derived from the parental mouse Lewis lung carcinoma cancer cells (LLC-Parental cells). In vitro assessment of stemness by RT-qPCR and western blot analysis of stem cell markers, clonogenic assay (p < 0.001), single cell spheroid formation assay (p < 0.05) and 96-well-plate single-cell cloning assay (p < 0.01) indicated that the LLC-ASD cells exhibited stronger stemness features in comparison to the LLC-Parental cells. In vivo, tumorigenicity of LLC-ASD cells, transplanted subcutaneously to the nude mice, was increased compared to that of LLC-parental cells (p < 0.05). Further, Neuralized1a, a regulator of ASD in normal stem cells, was highly expressed in the LLC-ASD cells. Silencing Neuralized1a expression in LLC-ASD cells by siRNA weakened the stemness features measured by the in vitro assays listed above (p < 0.05). The tumorigenic ability was also decreased in the nude mice upon Neuralized1a silencing (p < 0.05). Collectively, the present study suggests that Neuralized1a regulates the stemness of LLC-ASD cells which could be the new marker and therapeutic target of CSCs.

Zeb1 Regulates the Symmetric Division of Mouse Lewis Lung Carcinoma Stem Cells through Numb mediated by miR-31.

Symmetric cell division (SD) and asymmetric cell division (ASD) were the unique characteristics of stem cells and the mechanisms underlying stem cell renewal. While recent studies have identified the presence of SD and ASD in lung cancer stem cells (CSCs), the mechanisms regulating SD and ASD in cancer state have not been elucidated, mostly due to the lack of stable cellular models of SD and ASD in CSC research. In this study, the interaction between Zeb1, an Epithelial-Mesenchymal Transition (EMT) factor shown to regulate CSCs self-renew, and Numb, which regulates SD and ASD in the normal neural stem cell was investigated using the stable mouse Lewis lung adenocarcinoma SD (LLC-SD) and ASD (LLC-ASD) lines established from our previous study. The most significant finding derived from this line of research is that we have identified and molecularly ordered the axis of Zeb1-miR-31-Numb that regulates the SD, a mechanism of CSC self-renewal that has not been previously described. More specifically, the expression of Zeb1 and Numb were both significantly higher in LLC-SD than LLC-ASD cells. Silencing of Zeb1 or Numb expression lead to decreased ratio of SD and weakened single-cell cloning formation, tumor growth and tumor metastasis, respectively. The rescure experiments have molecularly ordered the regulation of Numb by Zeb1, indirectly mediated by miR-31. Moreover, we also provided preliminary evidence supporting the clinical relevance of our finding. In summary, our study provides a new insight for the self-renew of lung CSCs in which SD is regulated by the axis of Zeb1-miR-31-Numb.

Comparison of tumor biology of two distinct cell sub-populations in lung cancer stem cells.

Characterization of the stem-like properties of cancer stem cells (CSCs) remain indirect and qualitative, especially the ability of CSCs to undergo asymmetric cell division for self renewal and differentiation, a unique property of cells of stem origin. It is partly due to the lack of stable cellular models of CSCs. In this study, we developed a new approach for CSC isolation and purification to derive a CSC-enriched cell line (LLC-SE). By conducting five consecutive rounds of single cell cloning using the LLC-SE cell line, we obtained two distinct sub-population of cells within the Lewis lung cancer CSCs that employed largely symmetric division for self-renewal (LLC-SD) or underwent asymmetric division for differentiation (LLC-ASD). LLC-SD and LLC-ASD cell lines could be stably passaged in culture and be distinguished by cell morphology, stem cell marker, spheroid formation and subcutaneous tumor initiation efficiency, as well as orthotopic lung tumor growth, progression and survival. The ability LLC-ASD cells to undergo asymmetric division was visualized and quantified by the asymmetric segregation of labeled BrdU and NUMB to one of the two daughter cells in anaphase cell division. The more stem-like LLC-SD cells exhibited higher capacity for tumorigenesis and progression and shorter survival. As few as 10 LLC-SD could initiate subcutaneous tumor growth when transplanted to the athymic mice. Collectively, these observations suggest that the SD-type of cells appear to be on the top of the hierarchical order of the CSCs. Furthermore, they have lead to generated cellular models of CSC self-renewal for future mechanistic investigations.