SENP2 Reduces Hepatocellular Carcinoma Stemness and Improves Sorafenib Sensitivity Through Inactivating the AKT/GSK3β/CTNNB1 Pathway

BackgroundSmall ubiquitin-like modifier specific peptidase 2 (SENP2) suppresses the progression and chemoresistance of several cancers, while few studies report its role in hepatocellular carcinoma (HCC). This study aimed to evaluate the effect of SENP2 on stemness, sorafenib sensitivity, and downstream pathway in HCC, with validation of its molecular mechanisms by compensation experiment.MethodsSENP2 was regulated by plasmid transfection; meanwhile, in a compensation experiment, protein kinase B (AKT) was activated by SC79 treatment and β-catenin (CTNNB1) was overexpressed by plasmid transfection. After modification, sorafenib sensitivity was detected by cell counting kit-8 assay; stemness was evaluated by CD133+ cell proportion and sphere formation assay.ResultsSENP2 was decreased in HCC cell lines (including Hep3B, Li7, and Huh7) compared with normal human liver epithelial cell lines, which was further reduced in HCC stem cells than in normal HCC cells. Subsequently, SENP2 overexpression inhibited CD133+ cell proportion, decreased sphere formation ability, promoted sorafenib sensitivity, suppressed AKT and glycogen synthase kinase-3β (GSK3β) phosphorylation, and reduced CTNNB1 expression in Huh7 and Hep3B cells, while SENP2 knockdown showed the reverse effects. The following compensation experiment revealed that activating AKT or overexpressing CTNNB1 promoted CD133+ cell proportion and sphere formation ability but suppressed sorafenib sensitivity in Huh7 and Hep3B cells. Moreover, activating AKT or overexpressing CTNNB1 attenuated the effect of SENP2 overexpression on stemness and sorafenib sensitivity in Huh7 and Hep3B cells.ConclusionSENP2 suppresses HCC stemness and increases sorafenib sensitivity through inactivating the AKT/GSK3β/CTNNB1 signaling pathway.

ONLY A SMALL FRACTION OF CELLS PRODUCE ASSEMBLED CAPSIDS DURING TRANSFECTION-BASED MANUFACTURING OF ADENO-ASSOCIATED VIRUS VECTORS

Plasmid transfection of mammalian cells is the dominant platform used to produce adeno-associated virus (AAV) vectors for clinical and research applications. Low yields from this platform currently make it difficult to supply these activities with adequate material. In an effort to better understand the current limitations of transfection-based manufacturing, this study examines what proportion of cells in a model transfection produce appreciable amounts of assembled AAV capsid. Using conformation-specific antibody staining and flow cytometry we report the surprising result that despite obtaining high transfection efficiencies and nominal vector yields in our model system, only 5-10% of cells appear to produce measurable levels of assembled AAV capsids. This finding implies that considerable increases in vector titer could be realized through increasing the proportion of productive cells. Furthermore, we suggest that the flow cytometry assay used here to quantify productive cells may be a useful metric for future optimization of transfection-based AAV vector manufacturing platforms.

Berberine Inhibits FoxM1 Dependent Transcriptional Regulation of POLE2 and Interferes with the Survival of Lung Adenocarcinoma

Background：Berberine is one of the most interesting and promising natural anticancer drugs. POLE2 is involved in many cellular functions such as DNA replication and is highly expressed in a variety of cancers. However, the specific molecular mechanism of berberine interfering with POLE2 expression in lung adenocarcinoma (LUAD) is still unknown to a great extent.Method:The KEGG database (Release 91.0) and Gene Ontology (GO) category database were used for functional annotation of differentially expressed genes after berberine treatment. Reproducibility assessment using TCGA dataset. The biological functions of berberine in LUAD were investigated by a series of in vitro and in vivo experiments: MTT, colony formation, mouse xenograft and plasmid transfection. The molecular mechanisms of berberine were demonstrated by plasmid transfection, quantitative RT-PCR and Western blotting.Result:The elevated expression of FoxM1 and the high enrichment of DNA replication pathway were confirmed in LUAD by microarray and TCGA analysis, and were positively correlated with poor prognosis. Functionally, berberine inhibited the proliferation and survival of LUAD cell lines in vitro and in vivo. Mechanistically, berberine treatment down regulated the expression of FoxM1which closely related to survival, survival related genes in cell cycle and DNA replication pathway, and significantly down regulated the expression of survival related POLE2. Interestingly, we found that the transcription factor FoxM1 could act as a bridge between berberine and POLE2.Conclusion: Berberine significantly inhibited LUAD progression via the FoxM1/POLE2, and FoxM1/POLE2 may act as a clinical prognostic factor and a therapeutic target for LUAD. Berberine may be used as a promising therapeutic candidate for LUAD patients.

Cinnamic acid inhibits cell viability, invasion, and glycolysis in primary endometrial stromal cells by suppressing NF-κB-induced transcription of PKM2

Background: Endometriosis is a painful disorder characterized by the growth of endometrial tissue outside the uterine cavity. Here, we investigated the effects of the cinnamic acid isolated from the Chinese medicinal plant Cinnamomum cassia Presl on primary endometrial stromal cells. Methods: Immunohistochemistry was used to examine protein expression and cell purity. Quantitative RT-PCR was conducted to assess mRNA expression, and Western blot was performed to determine protein level. Cell viability was assessed using cell counting kit-8 (CCK-8) assay. Glycolysis and mitochondrial function were evaluated by measuring the extracellular acidification rate (ECAR) and the oxygen consumption rate (OCR) of cells, respectively. Lastly, plasmid transfection and inhibitor treatment were used for overexpression and inhibition studies. Results: Cinnamic acid inhibited cell viability and cell invasion, as well as decreased ECAR and OCR, in primary endometrial stromal cells. Cinnamic acid suppressed the effects of PKM2 overexpression, and inhibition of PKM2 using Compound 3k mimicked the effects of cinnamic acid. Treatment with Compound 3k and cinnamic acid did not lead to additive effects, but rather displayed effects similar to those of Compound 3k alone, suggesting that cinnamic acid elicits its effects on primary endometrial stromal cells by targeting PKM2. Conclusions: Our study identified cinnamic acid as a novel compound from Cinnamomum cassia Presl that displays potent effects on primary endometrial stromal cell viability, invasion, and glycolysis, suggesting its potential use for endometriosis treatment.

Molecular Characterization of an Aquaporin−2 Mutation Causing Nephrogenic Diabetes Insipidus

The aquaporin 2 (AQP2) plays a critical role in water reabsorption to maintain water homeostasis. AQP2 mutation leads to nephrogenic diabetes insipidus (NDI), characterized by polyuria, polydipsia, and hypernatremia. We previously reported that a novel AQP2 mutation (G215S) caused NDI in a boy. In this study, we aimed to elucidate the cell biological consequences of this mutation on AQP2 function and clarify the molecular pathogenic mechanism for NDI in this patient. First, we analyzed AQP2 expression in Madin-Darby canine kidney (MDCK) cells by AQP2-G215S or AQP2-WT plasmid transfection and found significantly decreased AQP2-G215S expression in cytoplasmic membrane compared with AQP2-WT, independent of forskolin treatment. Further, we found co-localization of endoplasmic reticulum (ER) marker (Calnexin) with AQP2-G215S rather than AQP2-WT in MDCK cells by immunocytochemistry. The functional analysis showed that MDCK cells transfected with AQP2-G215S displayed reduced water permeability compared with AQP2-WT. Visualization of AQP2 structure implied that AQP2-G215S mutation might interrupt the folding of the sixth transmembrane α-helix and/or the packing of α-helices, resulting in the misfolding of monomer and further impaired formation of tetramer. Taken together, these findings suggested that AQP2-G215S was misfolded and retained in the ER and could not be translocated to the apical membrane to function as a water channel, which revealed the molecular pathogenic mechanism of AQP2-G215S mutation and explained for the phenotype of NDI in this patient.

MicroRNA-487a-3p Regulates the Senescence of Mesenchymal Stem Cells by Targeting Silencing Information Regulator-Associated Enzyme 1 (SIRT1)

SIRT1 is known to be closely associated with cellular senescence, while the relationship between miR-487a-3p and SIRT1 and their role in mesenchymal stem cells (MSCs) remains unclear. MiRDB analysis showed SIRT1 is a target of miR-487a-3p. Here we investigated whether miR-487a-3p modulates senescence of mesenchymal stem cells by targeting SIRT1. The human MSCs (hMSCs) were divided into control group (NC group), miR-487a-3p Mimics group, pCMV-SIRT+miR-487a-3p Mimics group followed by analysis of miR-487a-3p expression by qPCR and protein level of SIRT1, P21 and P53 by western blot. Dual luciferin report assay verified the binding of miR-487a-3p to SIRT1 mRNA and β-galactosidase activity staining detected hMSCs senescence. miR-487a-3p level was significantly elevated after miR-487a-3p Mimics treatment (P <0.01) without difference between miR-487a-3p Mimics group and pCMV-SIRT1 group+miR-487a-3pMimics (P >0.05). miR-487a-3p mimics significantly decreased SIRT1 level (P < 0.01), which was reversed by pCMVSIRT1 plasmid transfection (P <0.05). Moreover, miR-487a-3p could bind SIRT1 mRNA 3′-UTR region. Further more, miR-487a-3p Mimics induced cellular senescence as displayed by increased β-galactosidase activity (P <0.01) and increased level of senescence-related proteins P21 and P53 (P < 0.01), which were all reversed by overexpression of SIRT1 (P < 0.05). In conclusion, miR-487a-3p reduced SIRT1 expression, thus promoting hMSCs senescence, while overexpression of SIRT1 could counteract the senescence of hMSCs induced by miR-487a-3p.

Upregulation of TCF21 inhibits migration of adrenocortical carcinoma cells

Background Adrenocortical carcinomas (ACC) are rare and aggressive cancer. Our previous study has revealed that the transcription factor 21, TCF21, is downregulated in ACC and regulates steroidogenic factor 1 (SF-1) binding to the SF-1 E-box promoter. In addition, it could be found that TCF21 is a predictor of overall survival (OS) in adult carcinomas. Methods In this study, it was investigated the correlation between TCF21 expression and the promoter methylation status in adrenocortical tumor cells, carcinomas and adenoma. The biological function and potential molecular mechanism of TCF21 restoration in migration and invasion of ACC cells was examined. Results We could be demonstrated a negative correlation between the level of TCF21 expression and methylation of its promoter in adenoma and carcinoma cells indicating the epigenetic control of TCF21 expression. It was also demonstrated that the expression of TCF21 inhibits migration and invasion in the ACC cell line, H295R cells, using plasmid transfection to express TCF21. Furthermore, it could be investigated the TCF21 function as tumor suppressor probably through Kisspeptin 1 (KISS-1) expression and epithelial–mesenchymal transition (EMT) reversion, as well as the modulation of several metalloproteinases in ACC cells. Conclusions Our results suggest that enhancement of TCF21 expression levels may be a potential strategy to revert invasive abilities in adrenocortical carcinomas.

Role of hepcidin in oxidative stress and cell death of cultured mouse renal collecting duct cells: protection against iron and sensitization to cadmium

The liver hormone hepcidin regulates systemic iron homeostasis. Hepcidin is also expressed by the kidney, but exclusively in distal nephron segments. Several studies suggest hepcidin protects against kidney damage involving Fe2+ overload. The nephrotoxic non-essential metal ion Cd2+ can displace Fe2+ from cellular biomolecules, causing oxidative stress and cell death. The role of hepcidin in Fe2+ and Cd2+ toxicity was assessed in mouse renal cortical [mCCD(cl.1)] and inner medullary [mIMCD3] collecting duct cell lines. Cells were exposed to equipotent Cd2+ (0.5–5 μmol/l) and/or Fe2+ (50–100 μmol/l) for 4–24 h. Hepcidin (Hamp1) was transiently silenced by RNAi or overexpressed by plasmid transfection. Hepcidin or catalase expression were evaluated by RT-PCR, qPCR, immunoblotting or immunofluorescence microscopy, and cell fate by MTT, apoptosis and necrosis assays. Reactive oxygen species (ROS) were detected using CellROX™ Green and catalase activity by fluorometry. Hepcidin upregulation protected against Fe2+-induced mIMCD3 cell death by increasing catalase activity and reducing ROS, but exacerbated Cd2+-induced catalase dysfunction, increasing ROS and cell death. Opposite effects were observed with Hamp1 siRNA. Similar to Hamp1 silencing, increased intracellular Fe2+ prevented Cd2+ damage, ROS formation and catalase disruption whereas chelation of intracellular Fe2+ with desferrioxamine augmented Cd2+ damage, corresponding to hepcidin upregulation. Comparable effects were observed in mCCD(cl.1) cells, indicating equivalent functions of renal hepcidin in different collecting duct segments. In conclusion, hepcidin likely binds Fe2+, but not Cd2+. Because Fe2+ and Cd2+ compete for functional binding sites in proteins, hepcidin affects their free metal ion pools and differentially impacts downstream processes and cell fate.

Role of Sialyl-O-Acetyltransferase CASD1 on GD2 Ganglioside O-Acetylation in Breast Cancer Cells

The O-acetylated form of GD2, almost exclusively expressed in cancerous tissues, is considered to be a promising therapeutic target for neuroectoderm-derived tumors, especially for breast cancer. Our recent data have shown that 9-O-acetylated GD2 (9-OAcGD2) is the major O-acetylated ganglioside species in breast cancer cells. In 2015, Baumann et al. proposed that Cas 1 domain containing 1 (CASD1), which is the only known human sialyl-O-acetyltransferase, plays a role in GD3 O-acetylation. However, the mechanisms of ganglioside O-acetylation remain poorly understood. The aim of this study was to determine the involvement of CASD1 in GD2 O-acetylation in breast cancer. The role of CASD1 in OAcGD2 synthesis was first demonstrated using wild type CHO and CHOΔCasd1 cells as cellular models. Overexpression using plasmid transfection and siRNA strategies was used to modulate CASD1 expression in SUM159PT breast cancer cell line. Our results showed that OAcGD2 expression was reduced in SUM159PT that was transiently depleted for CASD1 expression. Additionally, OAcGD2 expression was increased in SUM159PT cells transiently overexpressing CASD1. The modulation of CASD1 expression using transient transfection strategies provided interesting insights into the role of CASD1 in OAcGD2 and OAcGD3 biosynthesis, and it highlights the importance of further studies on O-acetylation mechanisms.