Identification of Hub Genes Correlated With Poor Prognosis for Patients With Uterine Corpus Endometrial Carcinoma by Integrated Bioinformatics Analysis and Experimental Validation.

Uterine Corpus Endometrial Carcinoma (UCEC) is one of the most common malignancies of the female genital tract and there remains a major public health problem. Although significant progress has been made in explaining the progression of UCEC, it is still warranted that molecular mechanisms underlying the tumorigenesis of UCEC are to be elucidated. The aim of the current study was to investigate key modules and hub genes related to UCEC pathogenesis, and to explore potential biomarkers and therapeutic targets for UCEC. The RNA-seq dataset and corresponding clinical information for UCEC patients were obtained from the Cancer Genome Atlas (TCGA) database. Differentially expressed genes (DEGs) were screened between 23 paired UCEC tissues and adjacent non-cancerous tissues. Subsequently, the co-expression network of DEGs was determined via weighted gene co-expression network analysis (WGCNA). The Blue and Brown modules were identified to be significantly positively associated with neoplasm histologic grade. The highly connected genes of the two modules were then investigated as potential key factors related to tumor differentiation. Additionally, a protein-protein interaction (PPI) network for all genes in the two modules was constructed to obtain key modules and nodes. 10 genes were identified by both WGCNA and PPI analyses, and it was shown by Kaplan-Meier curve analysis that 6 out of the 10 genes were significantly negatively related to the 5-year overall survival (OS) in patients (AURKA, BUB1, CDCA8, DLGAP5, KIF2C, TPX2). Besides, according to the DEGs from the two modules, lncRNA-miRNA-mRNA and lncRNA-TF-mRNA networks were constructed to explore the molecular mechanism of UCEC-related lncRNAs. 3 lncRNAs were identified as being significantly negatively related to the 5-year OS (AC015849.16, DUXAP8 and DGCR5), with higher expression in UCEC tissues compared to non-tumor tissues. Finally, quantitative Real-time PCR was applied to validate the expression patterns of hub genes. Cell proliferation and colony formation assays, as well as cell cycle distribution and apoptosis analysis, were performed to test the effects of representative hub genes. Altogether, this study not only promotes our understanding of the molecular mechanisms for the pathogenesis of UCEC but also identifies several promising biomarkers in UCEC development, providing potential therapeutic targets for UCEC.

Surf4 facilitates reprogramming by activating the cellular response to endoplasmic reticulum stress.

OBJECTIVES: Maternal factors that are enriched in oocytes have attracted great interest as possible key factors in somatic cell reprogramming. We found that surfeit locus protein 4 (Surf4), a maternal factor, can facilitate the generation of induced pluripotent stem cells (iPSCs) previously, but the mechanism remains elusive. MATERIALS AND METHODS: In this study, we investigated the function and mechanism of Surf4 in somatic cell reprogramming using a secondary reprogramming system. Alkaline phosphatase (AP) staining, qPCR and immunofluorescence (IF) staining of expression of related markers were used to evaluate efficiency of iPSCs derived from mouse embryonic fibroblasts. Embryoid body and teratoma formation assays were performed to evaluate the differentiation ability of the iPSC lines. RNA-seq, qPCR and western blot analysis were applied to validate the downstream targets of Surf4. RESULTS: Surf4 can significantly facilitate the generation of iPSCs in a proliferation-independent manner. When co-expressed with Oct4, Sox2, Klf4 and c-Myc (OSKM), Surf4 can activate the response to endoplasmic reticulum (ER) stress at the early stage of reprogramming. We further demonstrated that Hspa5, a major ER chaperone, and the active spliced form of Xbp1 (sXbp1), a major mediator of ER stress, can mimic the effects of Surf4 on somatic cell reprogramming. Concordantly, blocking the unfolded protein response compromises the effect of Surf4 on reprogramming. CONCLUSIONS: Surf4 promotes somatic cell reprogramming by activating the response to ER stress.

Nanoluciferase as a novel quantitative protein fusion tag: Application for overexpression and bioluminescent receptor-binding assays of human leukemia inhibitory factor.

Nanoluciferase (NanoLuc) is a newly developed small luciferase reporter with the brightest bioluminescence reported to date. In the present work, we developed NanoLuc as a novel quantitative protein fusion tag for efficient overexpression in Escherichia coli and ultrasensitive bioluminescent assays using human leukemia inhibitory factor (LIF) as a model protein. LIF is an interleukin 6 family cytokine that elicits pleiotropic effects on a diverse range of cells by activating a heterodimeric LIFR/gp130 receptor. Recombinant preparation of the biologically active LIF protein is quite difficult due to its hydrophobic nature and three disulfide bonds. Using the novel NanoLuc-fusion approach, soluble 6×His-NanoLuc-LIF fusion protein was efficiently overexpressed in E. coli and enzymatically converted to monomeric mature LIF. Both the mature LIF and the NanoLuc-fused LIF had high biological activities in a leukemia M1 cell proliferation inhibition assay and in a STAT3 signaling activation assay. The NanoLuc-fused LIF retained high binding affinities with the overexpressed LIFR (Kd = 1.4 ± 0.4 nM, n = 3), the overexpressed LIFR/gp130 (Kd = 115 ± 8 pM, n = 3), and the endogenously expressed LIFR/gp130 (Kd = 33.1 ± 3.2 pM, n = 3), with a detection limit of less than 10 receptors per cell. Thus, the novel NanoLuc-fusion strategy not only provided an efficient approach for preparation of recombinant LIF protein but also provided a novel ultrasensitive bioluminescent tracer for ligand-receptor interaction studies. The novel NanoLuc-fusion approach could be extended to other proteins for both efficient sample preparation and various bioluminescent quantitative assays in future studies.

All-trans retinoic acid negatively regulates cytotoxic activities of nature killer cell line 92.

NK cells are key components of innate immune systems and their activities are regulated by cytokines and hormones. All-trans retinoic acid (ATRA), as a metabolite of vitamin A and an immunomodulatory hormone, plays an important role in regulating immune responses. In the present study, we investigated the effect of ATRA on human NK cell line NK92. We found that ATRA dose-dependently suppressed cytotoxic activities of NK92 cells without affecting their proliferation. To explore the mechanisms underlying the ATRA influence on NK92 cells, we examined the production of cytokines (TNF-alpha, IFN-gamma), gene expression of cytotoxic-associated molecules (perforin, granzyme B, nature killer receptors (NCRs), and NKG2D), and the activation of NF-kappaB pathways related with immune response. Our results demonstrated that ATRA suppressed NF-kappaB activity and prevented IkappaBalpha degradation in a dose-dependent way, inhibited IFN-gamma production and gene expression of granzyme B and NKp46. Our findings suggest that ATRA is a negative regulator of NK92 cell activation and may act as a potential regulator of anti-inflammatory functions in vivo.