TSPAN1-elevated FAM110A promotes pancreatic cancer progression by transcriptionally regulating HIST1H2BK.

Background: FAM110A belongs to the FAM110 family, which mainly functions in biological processes associated with the cell cycle. However, the biological functions in which FAM110A participates are largely undefined. In particular, its potential role in cancer remains unknown. The goal of this study was to uncover the role and mechanism of FAM110A in pancreatic cancer. Methods: Based on bioinformatics databases, qPCR and Western blot assays, we verified the elevated expression level of FAM110A in PDAC. Subsequently, FAM110A, HIST1H2BK and TSPAN1 overexpression or knockdown stable transfected cells were employed for biological functions' studies to explore the role in PDAC in vitro and in vivo. RNA-Seq, Western blot and luciferase-reporter assays were used to explore mechanism of FAM110A action in PDAC, and the involved pathway was verified by tumor phenotypic rescue experiments. Results: In this study, we demonstrated for the first time that FAM110A is an oncogene that promotes cell proliferation, migration, invasion and tumorigenesis in pancreatic cancer. HIST1H2BK was identified as the downstream target of FAM110A, while the promotion effect caused by FAM110A overexpression could be abolished by HIST1H2BK knockdown. Moreover, for the first time, we revealed the oncogenic role of HIST1H2BK in pancreatic cancer, and the tumor-promoting capacity of HIST1H2BK may be associated with its regulatory effect on G9a. In addition, we demonstrated that TSPAN1 displayed a positive transcriptional regulatory effect on FAM110A. Conclusions: Collectively, FAM110A plays an oncogenic role in PDAC, and the newly identified TSPAN1/FAM110A/HIST1H2BK/G9a pathway is involved in the modulation of pancreatic cancer progression and provides a novel prognostic and therapeutic strategy for pancreatic cancer treatment.

Ascorbic Acid in Epigenetic Reprogramming.

Emerging evidence suggests that ascorbic acid (vitamin C) enhances the reprogramming process by multiple mechanisms primarily due to its cofactor role in Fe(II) and 2-oxoglutarate-dependent dioxygenases, including the DNA demethylases Ten Eleven Translocase (TET) and histone demethylases. Epigenetic variations have been shown to play a critical role in somatic cell reprogramming. DNA methylation and histone methylation are extensively recognized as barriers to somatic cell reprogramming. N6-methyladenosine (m6A), known as RNA methylation, is an epigenetic modification of mRNAs and has also been shown to play a role in regulating cellular reprogramming. Multiple cofactors are reported to promote the activity of these demethylases, including vitamin C. Therefore, this review focuses and examines the evidence and mechanism of vitamin C in DNA and histone demethylation and highlights its potential involvement in the regulation of m6A demethylation. It also shows the significant contribution of vitamin C in epigenetic regulation, and the affiliation of demethylases with vitamin C-facilitated epigenetic reprogramming.

Methods for Assessing the Regulation of a Kinase by the Rab GTPase Ypt1.

COPII coated vesicles that bud from the endoplasmic reticulum (ER) normally traffic to the Golgi. However, during starvation, COPII vesicles are redirected to the macroautophagy pathway where they become a membrane source for autophagosomes. Phosphorylation of the coat by the casein kinase 1 (CK1), Hrr25, is a prerequisite for vesicle uncoating and membrane fusion. CK1 family members were initially thought to be constitutively active kinases that are regulated through their subcellular localization. Recent studies, however, have shown that the Rab GTPase Ypt1 binds to and activates Hrr25 (CK1δ in mammals) to spatially regulate its kinase activity. Consistent with a direct role for Hrr25 in macroautophagy, hrr25and ypt1mutants are defective in autophagosome biogenesis. These studies have provided insights into how the itinerary of COPII vesicles is coordinated on two different trafficking pathways.

miR-216a-mediated upregulation of TSPAN1 contributes to pancreatic cancer progression via transcriptional regulation of ITGA2.

Pancreatic cancer (PC) is recognized as the most aggressive and deadliest malignancy because it has the highest mortality of all cancers in humans. Mutations in multiple tumor suppressors and oncogenes have been documented to be involved in pancreatic cancer progression and metastasis. The upregulation of tetraspanin 1 (TSPAN1), a transmembrane protein, has been reportedly observed in many human cancers. However, the role of TSPAN1 and its underlying molecular mechanisms in PC progression have not been fully elucidated. In this study, we validated the oncogenic role of TSPAN1 in PC, showing that TSPAN1 reinforces cell proliferation, migration, invasion and tumorigenesis. To investigate the upregulation of TSPAN1 in PC, we showed that miR-216a is the upstream negative regulator of TSPAN1 via direct binding to the TSPAN1 3'-untranslated region. Through RNA-Seq analysis, we for the first time revealed that TSPAN1 expression transcriptionally regulates ITGA2, which is involved in the actin cytoskeleton pathway. The stimulated cell proliferation and invasion initiated by TSPAN1 overexpression could be abolished by knockdown of ITGA2 in PC cells. Furthermore, TSPAN1 epigenetically regulates the expression of ITGA2 by modulating the levels of TET2 DNMT3B and DNMT1, resulting in hypomethylation of the CpG island of the ITGA2 promoter. In conclusion, the newly identified miR-216a/TSPAN1/ITGA2 axis is involved in the modulation of PC progression and represents a novel therapeutic strategy for future pancreatic cancer treatment.

Preparation, characterization, and in vivo evaluation of a polymorphic form of valnemulin hydrogen tartrate.

We prepared a polymorphic form of valnemulin hydrogen tartrate (Form I) to overcome the instability and irritating odor of valnemulin hydrochloride that affect its use in the production and application of veterinary drugs. The physicochemical properties of Form I were characterized by scanning electron microscopy, X-ray powder diffraction, infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. The results showed the crystal structure and thermal properties of Form I were very different from those of a commercially available form of valnemulin hydrogen tartrate (Form II). Form I and Form II were more stable than valnemulin hydrochloride after storage under irradiation and high humidity conditions, respectively. The solubility of Form I was 2.6 times that of Form II, and Form I was selected for use in pharmaceutical kinetics experiments in vivo. Compared to valnemulin hydrochloride, after oral administration at a dose of 10 mg/kg in pigs, Form I had similar pharmaceutical kinetic behavior but a slightly higher area under the concentration-time curve from time zero to the last measurable concentration. Consequently, Form I should be suitable for the development of simple formulations and be effective in the clinical application of veterinary drugs.

Down-Regulation of m6A mRNA Methylation Is Involved in Dopaminergic Neuronal Death.

N6-Methyladenosine (m6A) is the most prevalent internal modification that occurs in the mRNA of eukaryotes and plays a vital role in the post-transcriptional regulation. Recent studies highlighted the biological significance of m6A modification in the nervous system, and its dysregulation has been shown to be related to degenerative and neurodevelopmental diseases. Parkinson's disease (PD) is a common age-related neurological disorder with its pathogenesis still not fully elucidated. Reports have shown that epigenetic mechanisms including DNA methylation and histone acetylation, which alter gene expression, are associated with PD. In this study, we found that global m6A modification of mRNAs is down-regulated in 6-OHDA-induced PC12 cells and the striatum of PD rat brain. To further explore the relationship between m6A mRNA methylation and molecular mechanism of PD, we decreased m6A in dopaminergic cells by overexpressing a nucleic acid demethylase, FTO, or by m6A inhibitor. The results showed that m6A reduction could induce the expression of N-methyl-d-aspartate (NMDA) receptor 1, and elevate oxidative stress and Ca2+ influx, resulting in dopaminergic neuron apoptosis. Collectively, m6A modification may play a vital role in the death of dopaminergic neuron, which provides a novel view of mRNA methylation to understand the epigenetic regulation of Parkinson's disease.

Tet methylcytosine dioxygenase 1 promotes hypoxic gene induction and cell migration in colon cancer.

Ten-eleven translocation 1 (TET1), a widely reported DNA demethylation protein, has been associated with tumorigenesis and metastasis. However, whether TET1 is an oncogene or tumor suppressor gene has been controversial; the mechanism of how TET1 affects cancer progression remains unclear. The current study aims to investigate how TET1 is changed in the tumor microenvironment and to explore the mechanisms of how TET1 affects colon cancer progression. Because hypoxia prevails on solid tumors, we established an important connection between hypoxia and DNA demethylation in tumorigenesis. By qPCR and RNA interference (RNAi) technology, we found that hypoxia increased TET1 expression with a hypoxia-inducible factor-1-alpha (HIF-1α)-dependent manner. By CHIP-qPCR and pyrosequencing technology, we demonstrated that TET1 regulated the target gene expression of HIF-1α through HIF-1α binding to hypoxia-responsive elements (HREs), and HIF-1α binding to HREs depended on CpG methylation levels. By Cell Counting Kit-8 (CCK-8) and transwell assay, we showed that loss of TET1 did not affect cell proliferation but inhibited migration. We also identified two novel gene mutants of TET1 in 120 paired tumor/normal tissue specimens by DNA sequencing and found that TET1 E2082K mutant blocked the TET1-enhanced cell migration. Our results showed that the downregulation of TET1 rescued the abnormally high levels of gene expression resulting from hypoxia in tumors and reduced the migration activity of tumor cells, suggesting a therapeutic role by interference with TET1 in colon cancer treatment. By demonstrating that hypoxia upregulated TET1 and that TET1 drove HIF-1α-responsive genes, we showed that an epigenetic mechanism and tumor microenvironment-driven models coexisted and mutually affected colon cancer.

Fusion with mesenchymal stem cells differentially affects tumorigenic and metastatic abilities of lung cancer cells.

Cell fusion plays a crucial role in cancer progression and leads to massive aberrant changes in chromosome and gene expression involved in tumor metastasis. Cancer cells can fuse with many cell types, including stromal cells, epithelial cells, macrophages, and endothelial cells. Mesenchymal stem cells (MSCs) have been reported to migrate and incorporate into tumor sites during cancer progression. However, the underlying mechanism of stem cell fusion in tumor metastasis has not been fully deciphered. In this research, we established a cell fusion model between lung cancer cells and MSCs in vitro. We found that the hybrid cells showed enhanced metastatic capacity with increased expression of MMP-2 and MMP-9, whereas the proliferation ability was inhibited and cell cycle was blocked in the G0 /G1 phase with elevated expression of p21, p27, and p53. Moreover, the hybrid cells lost epithelial morphology and exhibited an epithelial-mesenchymal transition (EMT) change with downregulation of E-cadherin and upregulation of N-cadherin, Vimentin, α-SMA and Fibronectin1. Meanwhile, the expressions of EMT transcription factors, including Snail1, Slug, Twist1, Zeb1, and Zeb2, were also increased in hybrid cells. More important, the fusion hybrids acquired stem cell-like properties, which exhibited increased expression stem cell transcription factors Oct4, Sox2, Nanog, Kif4 as well as Bmi1. Taken together, our results suggested that cell fusion between lung cancer cells and MSCs offered enhanced metastatic capacity and characteristics of cancer stem cell by undergoing EMT. This study will contribute to explaning the origin of lung cancer stem cells and to elucidate the role of cell fusion in cancer metastasis.

Upregulation of Coxsackie Adenovirus Receptor Sensitizes Cisplatin-Resistant Lung Cancer Cells to CRAd-Induced Inhibition.

Objective. Conditionally replicating adenoviruses (CRAds) have been proven potent oncolytic viruses in previous studies. They selectively replicate in the tumor cells because of incorporated survivin promoter and ultimately lead to their killing with minimal side effects on normal tissue. Chemotherapy with cisplatin is commonly employed for treating tumors, but its cytotoxic effects and development of resistance remained major concerns to be dealt with. The aim of this study was to explore the anticancer potential of survivin regulated CRAd alone or in combination with cisplatin in the A549 lung cancer cell line and cisplatin-resistant lung cancer cell line, A549-DDPR. Methods. CRAd was genetically engineered in our laboratory by removing its E1B region and adding survivin promoter to control its replication. A549, H292, and H661 lung cancer cell lines were procured from the CAS-China. The anti-tumor effectiveness of combined treatment (cisplatin plus CRAd) was evaluated in vitro through MTS assays and in vivo through mouse model experimentation. RT- PCR was used to assess MDR gene and mRNA expression of coxsackie adenoviral receptor (CAR). Results. Results of in vitro studies established that A549 lung cancer cells were highly sensitive to cisplatin showing dose-dependent inhibition. The resistant cells of A549-DDPR exhibited very less sensitivity to cisplatin but were infected with CRAd more efficiently as compared to A549. A549-DDPR cells exhibited higher expression of MDR gene and CAR in the RT-PCR analysis. The nearly similar rise in the CAR expression was seen when lung cancer cell lines received cisplatin in combined treatment (cisplatin plus CRAd). Combined anti-cancer therapy (cisplatin plus oncolytic virus) proved more efficient than monotherapy in the killing of cancer cells. Results of in vivo experiments recapitulated nearly similar tumor inhibition activities. Conclusion. This study highlighted the significant role of survivin in gene therapy as it has the potential to render CRAd more tumor specific. It also establishes that higher CAR expression plays a vital role in the success of adenovirus-based therapies. Furthermore, a careful combination of chemotherapy drugs and oncolytic viruses can culminate in significant therapeutic achievements against cancer.

IRES-Mediated Protein Translation Overcomes Suppression by the p14ARF Tumor Suppressor Protein.

Internal ribosome entry sites (IRES elements) have attracted interest in cancer gene therapy because they can be used in the design of gene transfer vectors that provide bicistronic co-expression of two transgene products under the control of a single promoter. Unlike cellular translation of most mRNAs, a process that requires a post-translational 5' modification of the mRNA known as the cap structure, IRES-mediated translation is independent of the cap structure. The cellular conditions that may intervene to modulate IRES-mediated, cap-independent versus cap-dependent translation, however, remain poorly understood, although they could be critical to the choice of gene transfer vectors. Here we have compared the effects of the p14ARF (Alternate Reading Frame) tumor suppressor, a translational suppressor frequently overexpressed in cancer, on cap-dependent translation versus cap-independent translation from the EMCV viral IRES often used in bicistronic gene transfer vectors. We find that ectopic overexpression of p14ARF suppresses endogenous and ectopic cap-dependent protein translation, consistent with other studies. However, p14ARF has little or no effect on transgene translation initiated within an IRES element. This suggests that transgenes placed downstream of an IRES element will retain efficient translation of their gene products in the presence of high levels of ectopic or endogenous p14ARF, a finding that could be particularly relevant to therapeutic gene therapy strategies for cancer.