Metabolic changes during malignant transformation in primary cells of oral lichen planus: Succinate accumulation and tumour suppression.

Oral squamous cell carcinoma (OSCC) is usually diagnosed at late stages, which leads to high morbidity. There are evidence that chronic inflammation (eg oral lichen planus [OLP]) was a risk factor of OSCC, but often misdiagnosed or ignored until invasion and metastasis. By applying precision medicine, the molecular microenvironment variations and relevant biomarkers for the malignant transformation from OLP to OSCC can be fully investigated. Several studies pointed out that the metabolic pathway were suppressed in OSCC. However, it remains unclear how the systemic profile of the metabolites change during the malignant transformation. In this study, we examined and compared the mucosa samples from 11 healthy individuals, 10 OLP patients and 21 OSCC patients. Based on the results, succinate, a key metabolite of the tricarboxylic acid cycle pathway, was accumulated in the primary cultured precancerous OLP keratinocytes and OSCC cells. Then, we found that succinate activated the hypoxia-inducible factor-1 alpha (HIF-1α) pathway and induced apoptosis, which could also be up-regulated by the tumour suppressor lncRNA MEG3. These results suggested the critical roles of succinate and MEG3 in the metabolic changes during malignant transformation from OLP to OSCC, which indicated that succinate, HIF1α and downstream proteins might serve as new biomarkers of precancerous OLP for early diagnosis and therapeutic monitoring. In addition, succinate or its prodrugs might become a potential therapy for the prevention or treatment of OSCC.

Identification of novel vascular projections with cellular trafficking abilities on the microvasculature of pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is a nearly lethal neoplasm. It is a remarkably stroma-rich, vascular-poor and hypo-perfused tumour, which prevents efficient drug delivery. Paradoxically, the neoplastic cells have robust glucose uptake, suggesting that the microvasculature has adopted an alternative method for nutrient uptake and cellular trafficking. Using adapted thick tumour section immunostaining and three-dimensional (3D) construction imaging in human tissue samples, we identified an undiscovered feature of the mature microvasculature in advanced PDAC tumours; long, hair-like projections on the basal surface of microvessels that we refer to as 'basal microvilli'. Functionally, these basal microvilli have an actin-rich cytoskeleton and endocytic and exocytic properties, and contain glucose transporter-1 (GLUT-1)-positive vesicles. Clinically, as demonstrated by PET-CT, the tumour microvasculature with the longest and most abundant basal microvilli correlated with high glucose uptake of the PDAC tumour itself. In addition, these basal microvilli were found in regions of the tumour with low GLUT-1 expression, suggesting that their presence could be dependent upon the glucose concentration in the tumour milieu. Similar microvasculature features were also observed in a K-Ras-driven model of murine PDAC. Altogether, these basal microvilli mark a novel pathological feature of PDAC microvasculature. Because basal microvilli are pathological features with endo- and exocytic properties, they may provide a non-conventional method for cellular trafficking in PDAC tumours.

Polycomb group protein PHF1 regulates p53-dependent cell growth arrest and apoptosis.

Polycomb group protein PHF1 is well known as a component of a novel EED-EZH2·Polycomb repressive complex 2 complex and plays important roles in H3K27 methylation and Hox gene silencing. PHF1 is also involved in the response to DNA double-strand breaks in human cells, promotes nonhomologous end-joining processes through interaction with Ku70/Ku80. Here, we identified another function of PHF1 as a potential p53 pathway activator in a pathway screen using luminescence reporter assay. Subsequent studies showed PHF1 directly interacts with p53 proteins both in vivo and in vitro and co-localized in nucleus. PHF1 binds to the C-terminal regulatory domain of p53. Overexpression of PHF1 elevated p53 protein level and prolonged its turnover. Knockdown of PHF1 reduced p53 protein level and its target gene expression both in normal state and DNA damage response. Mechanically, PHF1 protects p53 proteins from MDM2-mediated ubiquitination and degradation. Furthermore, we showed that PHF1 regulates cell growth arrest and etoposide-induced apoptosis in a p53-dependent manner. Finally, PHF1 expression was significantly down-regulated in human breast cancer samples. Taken together, we establish PHF1 as a novel positive regulator of the p53 pathway. These data shed light on the potential roles of PHF1 in tumorigenesis and/or tumor progression.

The conditioned medium from a stable human GDF3-expressing CHO cell line, induces the differentiation of PC12 cells.

Members of the transforming growth factor-ß (TGF-ß) superfamily have significant roles in the regulation of a wide variety of physiological processes. In our present work, phylogenetic tree analysis showed that human GDF3 (Growth and differentiation factor 3) and human GDF1 formed a subgroup of closely related molecules. Through quantitative real-time PCR analysis in different human tissues, GDF1 and GDF3 expression level had a big difference in brain. GDF3 could activate downstream signaling through associating with ALK7 (Activin receptor-like kinase 7) in a Cripto-dependent fashion. A CHO cell line stably transfected with the encoding sequence of GDF3, named CHO-GDF3, was established. Western blotting analysis demonstrated that GDF3 protein could be secreted into the medium from CHO cells and immunofluorescence experiment showed that GDF3 was mainly distributed in cytoplasm of the stable cell line, the primary hippocampal neurons, and brain tissues. Furthermore, the conditioned medium from CHO-GDF3 could reduce PC12 cell growth and induce cell differentiation. All these findings bring new insights into the functional study of GDF3.

Cloning and characterization of a PI-like MADS-box gene in Phalaenopsis orchid.

The highly evolved flowers of orchids have colorful sepals and fused columns that offer an opportunity to discover new genes involved in floral development in monocotyledon species. In this investigation, we cloned and characterized the homologous PISTALLATA-like (PI-like) gene PhPI15 (Phalaenopsis PI STILLATA # 15), from the Phalaenopsis hybrid cultivar. The protein sequence encoded by PhPI15 contains a typical PI-motif. Its sequence also formed a subclade with other monocot PI-type genes in phylogenetic analysis. Southern analysis showed that PhPI15 was present in the Phalaenopsis orchid genome as a single copy. Furthermore, it was expressed in all the whorls of the Phalaenopsis flower, while no expression was detected in vegetative organs. The flowers of transgenic tobacco plants ectopically expressing PhPI15 showed male-sterile phenotypes. Thus, as a Class-B MADS-box gene, PhPI15 specifies floral organ identity in orchids.

EFCBP1/NECAB1, a brain-specifically expressed gene with highest abundance in temporal lobe, encodes a protein containing EF-hand and antibiotic biosynthesis monooxygenase domains.

Human EFCBP/NECAB family consists of important participants in neuronal calcium signaling, including EFCBP1/NECAB1, EFCBP2/NECAB2 and EFCBP3/NECAB3. In the present study, we identified the full-length 5229 bp EFCBP1 cDNA which was not described before. Human EFCBP1 encodes a 351 amino acid protein containing two EF-hand motifs and an antibiotic biosynthesis monooxygenase (ABM) domain, sharing 49.9 and 56.8% global homology with human EFCBP2 and EFCBP3. Northern hybridization revealed that EFCBP1 is specifically expressed in brain and its abundance varies in different brain regions. EFCBP1's abundance in temporal lobe, frontal lobe and occipital pole is about 3.4, 1.9 and 1.5 folds of the average abundance in cerebral cortex, respectively. The expression level of EFCBP1 equals in putamen and cerebral cortex, while no hybridization signal was detected in spinal cord. In addition, we found that EFCBP1, EFCBP2 and EFCBP3 share a similar exon distribution mode, though their chromosomal localizations, genomic sizes and intron sizes are diverse.

Identification of the key genes implicated in the transformation of OLP to OSCC using RNA-sequencing.

Oral lichen planus (OLP) is a chronic inflammatory disease that may transform to oral squamous cell carcinoma (OSCC), while its carcinogenesis mechanisms are not entirely clear. This study was designed to identify the important genes involved in the malignant transformation of OLP to OSCC. After RNA-sequencing, the differently expressed genes (DEGs) in OLP vs. normal and OSCC vs. normal groups, respectively, were identified by limma package in R language, and then clustering analysis were conducted by Pheatmap package in R language. Weighed gene co-expression network analysis (WGCNA) was performed for the DEGs to screen disease-associated modules. Using Cytoscape software, co-expression networks were constructed for the genes involved in the modules. Enrichment analysis was conducted for the genes involved in the co-expression networks using GOstat package in R language. Finally, quantitative real-time PCR (qRT-PCR) experiments were conducted to validate the key genes. There were, respectively, 223 and 548 DEGs in OLP vs. normal and OSCC vs. normal groups. WGCNA identified the blue modules for the DEGs in the two groups as disease-associated modules. Moreover, 19 common DEGs (including upregulated BCL9L, PER2 and TSPAN33, and downregulated GMPS and HES1) associated with both OLP and OSCC were identified. In the co-expression networks, BCL9L, HES1, PER2 and TSPAN33 might function in OLP via interactions (such as BCL9L-TSPAN33 and HES1-PER2). qRT-PCR analysis showed that BCL9L, PER2 and TSPAN33 were significantly upregulated, and GMP and HES1 were downregulated. These findings indicated that BCL9L, GMPS, HES1, PER2 and TSPAN33 affected the transformation of OLP to OSCC.

Suppression of MAPK11 or HIPK3 reduces mutant Huntingtin levels in Huntington's disease models.

Most neurodegenerative disorders are associated with accumulation of disease-relevant proteins. Among them, Huntington disease (HD) is of particular interest because of its monogenetic nature. HD is mainly caused by cytotoxicity of the defective protein encoded by the mutant Huntingtin gene (HTT). Thus, lowering mutant HTT protein (mHTT) levels would be a promising treatment strategy for HD. Here we report two kinases HIPK3 and MAPK11 as positive modulators of mHTT levels both in cells and in vivo. Both kinases regulate mHTT via their kinase activities, suggesting that inhibiting these kinases may have therapeutic values. Interestingly, their effects on HTT levels are mHTT-dependent, providing a feedback mechanism in which mHTT enhances its own level thus contributing to mHTT accumulation and disease progression. Importantly, knockout of MAPK11 significantly rescues disease-relevant behavioral phenotypes in a knockin HD mouse model. Collectively, our data reveal new therapeutic entry points for HD and target-discovery approaches for similar diseases.

Isolation and characterization of the human D-glyceric acidemia related glycerate kinase gene GLYCTK1 and its alternatively splicing variant GLYCTK2.

Deficiency of human glycerate kinase leads to D-glycerate acidemia/D-glyceric aciduria. Through PCR cloning assisted by in silico approach, we isolated the human glycerate kinase genes--Glycerate Kinase 1 (GLYCTK1) and its alternatively splicing variant--Glycerate Kinase 2 (GLYCTK2), which might be associated with D-glycerate acidemia/D-glyceric aciduria. The locus of GLYCTK gene is mapped to 3p21. PCR amplification in seventeen human tissue cDNAs revealed that both GLYCTK1 and GLYCTK2 are expressed widely almost in all these tissues. The expression of mouse Glyctk in various tissues was demonstrated by in situ hybridization. Both GLYCTK1 and GLYCTK2 proteins are localized in cytosol, and GLYCTK2 proteins are specifically localized in mitochondria. Present results revealed the characteristic expression pattern of murine Glyctk in neural system, skeleton muscle, supporting that glycerate kinase is implicated in D-glycerate acidemia/D-glyceric aciduria.

Expression pattern of growth/differentiation factor 3 in human and murine cerebral cortex, hippocampus as well as cerebellum.

Growth/differentiation factor 3 is a member of GDF/BMP subfamily of the TGF-beta superfamily, which has been reported to be implicated in testis carcinoma and deposition of adipose tissue. Interestingly, present work indicated that GDF3/Gdf3 genes were expressed in cerebral cortex, hippocampus as well as in cerebellum, as revealed by RT-PCR, in situ hybridization and immunostaining. Results of RT-PCR in 10 human tissues and 12 rat tissues indicated that GDF3/Gdf3 genes were abundantly transcribed in both human and murine brain, including cerebral cortex, hippocampus and cerebellum. In situ hybridization and immunohistochemistry results revealed that in cerebral cortex, GDF3 was evenly distributed. In hippocampus, it was expressed in most of the neurons in CA2 and DG region, especially only in a restricted number of neurons in the regions of CA1 and CA3 and in Purkinje cells in cerebellum. Present data suggested that GDF3 might play important roles in the central nervous system (CNS), especially in cerebral cortex, hippocampus and cerebellum, and it shed new light on further research of GDF3 in the central nervous system.

Isolation and characterization of novel human short-chain dehydrogenase/reductase SCDR10B which is highly expressed in the brain and acts as hydroxysteroid dehydrogenase.

Hydroxysteroid dehydrogenase belongs to the subfamily of short-chain dehydrogenases/reductases (SDR), and 11-beta-hydroxysteroid dehydrogenase catalyzes the interconversion of inactive glucocorticoids (cortisone in human, dehydrocorticosterone in rodents) and active glucocorticoids (cortisol in human, corticosterone in rodents). We report here the cloning and characterization of a novel human SDR gene SCDR10B which encodes a protein with similarity to 11beta-hydroxysteroid dehydrogenase 1. SCDR10B was isolated from a human brain cDNA library, and was mapped to chromosome 19p13.3 by browsing the UCSC genomic database. It contains an ORF with a length of 858 bp, encoding a protein with a transmembrane helix and SDR domain. Its molecular mass and isoelectric point are predicted to be 30.8 kDa and 10.3 kDa, respectively. SCDR10B protein is highly conserved in mammals and fish. Phylogenetic tree analysis indicated that SCDR10B stands for a new subgroup in the 11beta-hydroxysteroid dehydrogenase family. Northern blot analysis showed that SCDR10B was highly expressed in brain, and a strong expression signal was detected in hippocampal neurons by immunohistochemical analysis. RT-PCR and immunohistochemical analysis showed that SCDR10B was up-regulated in lung-cancer cell lines and human lung cancer. SCDR10B can catalyze the dehydrogenation of cortisol in the presence of NADP(+), and therefore it is a hydroxysteroid dehydrogenase.

SQUA-like genes in the orchid Phalaenopsis are expressed in both vegetative and reproductive tissues.

The SQUA family (AP1/FUL family) of MADS-box genes plays an important role in the transition from the vegetative to the reproductive development of angiosperms, and its origin might be concurrent with fixation of floral structure in angiosperms. Here, we isolated two Phalaenopsis MADS-box genes designated ORAP11 and ORAP13, both of which belong to the monocot FUL-like clade of the SQUA family. RT-PCR showed that both genes are strongly expressed in the floral bud, and also detected in the vegetative organs. During later stages, ORAP11 was only detected in the column, but ORAP13 signal was absent from all of the floral organs. In-situ hybridization experiments detected both genes in the tips and margins of developing petals and lips, the developing column, and ovule. Over-expression of both genes in tobacco induced early flowering and changed plant architecture. Our results suggest that in Phalaenopsis, both genes might share partly redundant activities and play important roles in the process of floral transition and morphological architecture.

TSSK5, a novel member of the testis-specific serine/threonine kinase family, phosphorylates CREB at Ser-133, and stimulates the CRE/CREB responsive pathway.

Several protein kinases have been shown to be involved in spermatogenesis. Recently, a novel subfamily of serine/threonine kinases has been isolated whose expression is limited to testis. Here, we report the fifth family member, named TSSK5, which encodes a 328 amino acid protein. RT-PCR analysis showed that TSSK5 is exclusively expressed in human testis. We isolated cAMP responsive element binding protein (CREB), a TSSK5 interacting protein via yeast two-hybrid system. The in vitro kinase assay showed that TSSK5 phosphorylated CREB at Ser-133. Using a CRE reporter system, we found that TSSK5 could stimulate the CREB/CRE responsive pathway in Hek293 cells. These results suggest that this kinase may be involved in spermatogenesis through phosphorylating CREB and then stimulating the CREB/CRE responsive pathway.