NAP1L1 regulates BIRC2 ubiquitination modification via E3 ubiquitin ligase UBR4 and hence determines hepatocellular carcinoma progression.

We have previously shown that nucleosome assembly protein 1-like 1 (NAP1L1) plays an important role in the abnormal proliferation of hepatocellular carcinoma (HCC) cells. However, the effects of NAP1L1 on the malignant behaviour of HCC cells, including cell migration, invasion and apoptosis, remain unclear. Baculoviral IAP repeat-containing 2 (BIRC2) plays a key role in initiating the abnormal proliferation, apoptotic escape and multidrug resistance of HCC cells; however, the mechanisms through which its stability is regulated in HCC remain elusive. Here, we found that knockdown of NAP1L1 inhibited the proliferation of HCC cells and activated apoptotic pathways but did not remarkably affect the migratory and invasive abilities of HCC cells. In addition, knockdown of NAP1L1 did not alter the expression of BIRC2 at the transcriptional level but substantially reduced its expression at the translational level, suggesting that NAP1L1 is involved in the post-translational modification (such as ubiquitination) of BIRC2. Furthermore, BIRC2 was highly expressed in human HCC tissues and promoted the proliferation and apoptotic escape of HCC cells. Co-immunoprecipitation (Co-IP) assay and mass spectrometry revealed that NAP1L1 and BIRC2 did not bind to each other; however, ubiquitin protein ligase E3 component n-recognin 4 (UBR4) was identified as an intermediate molecule associating NAP1L1 with BIRC2. Knockdown of NAP1L1 promoted the ubiquitin-mediated degradation of BIRC2 through the ubiquitin-protein junction of UBR4, which in turn inhibited the proliferation and apoptotic escape of HCC cells and exerted anti-tumour effects. In conclusion, this study reveals a novel mechanism through which NAP1L1 regulates the ubiquitination of BIRC2 through UBR4, thereby determining the progression of HCC. Based on this mechanism, suppression of NAP1L1 may inhibit tumour progression in patients with HCC with high protein expression of NAP1L1 or BIRC2.

[Oenothein B inhibits proliferation and migration of breast cancer cells by regulating P53].

The effects of oenothein B(OEB) on the proliferation, apoptosis, invasion, and migration of breast cancer MCF-7 and MDA-MB-231 cells were investigated by cell culture in vitro, network pharmacology, and molecular docking. In vitro cell experiments revealed that OEB inhibited the proliferation and colony formation ability, and promoted the apoptosis and formation of apoptotic bodies in breast cancer cells, as well as inhibited the invasion and migration of breast cancer cells. The targets of OEB were obtained using SwissTargetPrediction database and breast cancer targets were obtained from GeneCards. The targets of OEB and breast cancer were entered separately in Venny 2.1 software to obtain the Venn diagram of common targets of OEB and breast cancer. The common targets of OEB and breast cancer were input into STRING database to construct a protein-protein interaction(PPI) network, which was entered into Cytoscape 3.7.2 software for network topology analysis. Key targets were screened according to protein association strength, and analyzed for KEGG pathway enrichment. Molecular docking of OEB to key targets using AutoDock software revealed that OEB stably bound to the active pocket of P53, while OEB promoted the expression of P53 protein. MCF-7 and MDA-MB-231 cell viability and migration ability increased after silencing P53, and this change was reversed after treatment with OEB. Therefore, this study showed that OEB inhibited the proliferation, migration, and invasion of breast cancer MCF-7 and MDA-MB-231 cells, and promoted the apoptosis of breast cancer MCF-7 and MDA-MB-231 cells, which may be related to the targeted regulation of P53.

[p53 regulates primordial follicle activation through the mTOR signaling pathway].

This paper aimed to investigate the role and potential mechanism of p53 on primordial follicle activation. Firstly, the p53 mRNA expression in the ovary of neonatal mice at 3, 5, 7 and 9 days post-partum (dpp) and the subcellular localization of p53 were detected to confirm the expression pattern of p53. Secondly, 2 dpp and 3 dpp ovaries were cultured with p53 inhibitor Pifithrin-µ (PFT-µ, 5 µmol/L) or equal volume of dimethyl sulfoxide for 3 days. The function of p53 in primordial follicle activation was determined by hematoxylin staining and whole ovary follicle counting. The proliferation of cell was detected by immunohistochemistry. The relative mRNA levels and protein levels of the key molecules involved in the classical pathways associated with the growing follicles were examined by immunofluorescence staining, Western blot and real-time PCR, respectively. Finally, rapamycin (RAP) was used to intervene the mTOR signaling pathway, and ovaries were divided into four groups: Control, RAP (1 µmol/L), PFT-µ (5 µmol/L), PFT-µ (5 µmol/L) + RAP (1 µmol/L) groups. The number of follicles in each group was determined by hematoxylin staining and whole ovary follicle counting. The results showed that the expression of p53 mRNA was decreased with the activation of primordial follicles in physiological condition. p53 was expressed in granulosa cells and oocyte cytoplasm of the primordial follicles and growing follicles, and the expression of p53 in the primordial follicles was higher than that in the growing follicles. Inhibition of p53 promoted follicle activation and reduced the primordial follicle reserve. Inhibition of p53 promoted the proliferation of the granulosa cells and oocytes. The mRNA and protein expression levels of key molecules in the PI3K/AKT signaling pathway including AKT, PTEN, and FOXO3a were not significantly changed after PFT-µ treatment, while the expression of RPS6/p-RPS6, the downstream effectors of the mTOR signaling pathway, was upregulated. Inhibition of both p53 and mTOR blocked p53 inhibition-induced primordial follicle activation. Collectively, these findings suggest that p53 may inhibit primordial follicle activation through the mTOR signaling pathway to maintain the primordial follicle reserve.

Antihyperuricemia and antigouty arthritis effects of Persicaria capitata herba in mice.

BACKGROUND: Hyperuricemia (HUA) is an important risk factor for gout, renal dysfunction and cardiovascular diseases. The whole plant of Persicaria capitata (Buch.-Ham. ex D. Don) H. Gross, namely Persicaria capitata herba, is a well-known ethnic herb with potent therapeutic effects on urinary tract infections and urinary calculus, yet previous reports have only focused on its effect on urinary tract infections. PURPOSE: To evaluate the therapeutic potential of P. capitata herba against gout by investigating its antihyperuricemia and antigouty arthritis effects and possible mechanisms. METHODS: The ethanol extract (EP) and water extract (WP) of P. capitata herba were prepared by extracting dried and ground whole plants of P. capitata with 75% ethanol and water, respectively, followed by removal of solvents and characterization by UHPLC-Q-TOF/MS. The antihyperuricemia and antigouty arthritis effects of the two extracts were evaluated in a potassium oxonate- and hypoxanthine-induced hyperuricemia mouse model and a monosodium urate crystal (MSUC)-induced acute gouty arthritis mouse model, respectively. The mechanisms were investigated by testing their effects on the expression of correlated proteins (by Western blot) and mRNAs (by RT-PCR). RESULTS: UHPLC-HRMS fingerprinting and two chemical markers (i.e., quercetin and quercitrin) determination were used for the characterization of the WP and EP extracts. Both WP and EP extracts showed pronounced antihyperuricemia activities, with a remarkable decline in serum uric acid and a marked increase in urine uric acid in hyperuricemic mice. Unlike the clinical xanthine oxidase (XOD) inhibitor allopurinol, WP and EP did not show any distinct renal toxicities. The underlying antihyperuricemia mechanism involves the inhibition of the activity and expression of XOD and the downregulation of the mRNA and protein expression of glucose transporter 9 (GLUT9) and urate transporter 1 (URAT1). The extracts of P. capitata herba also demonstrated remarkable anti-inflammatory activity in MSUC-induced acute gouty arthritis mice. The mechanism might involve inhibitory effects on the expression of proinflammatory factors. CONCLUSIONS: The extracts of P. capitata herba possessed pronounced antihyperuricemia and antigouty arthritis effects and were, therefore, promising natural medicines for hyperuricemia-related disorders and gouty arthritis. The use of P. capitata herba for the treatment of urinary calculus may be, at least to some degree, related to its potential as an antihyperuricemia and antigouty arthritis drug.

Proteomic analysis of the effects of cell culture density on the metastasis of breast cancer cells.

Cancer cell progression and proliferation increase cell density, resulting in changes to the tumour site, including the microenvironment. What is not known is if increased cell density influences the aggressiveness of cancer cells, especially their proliferation, migration, and invasion capabilities. In this study, we found that dense cell culture enhances the aggressiveness of the metastatic cancer cell lines, 4T1 and ZR-75-30, by increasing their proliferation, migration, and invasion capabilities. However, a less metastatic cell line, MCF-7, did not show an increase in aggressiveness, following dense cell culture conditions. We conducted a differential proteomic analysis on 4T1 cells cultured under dense or sparse conditions and identified an increase in expression for proteins involved in migration, including focal adhesion, cytoskeletal reorganization, and transendothelial migration. In contrast, 4T1 cells grown under sparse conditions had higher expression levels for proteins involved in metabolism, including lipid and phospholipid binding, lipid and cholesterol transporter activity, and protein binding. These results suggest that the high-density tumour microenvironment can cause a change in cellular behaviour, leading towards more aggressive cancers. SIGNIFICANCE OF THE STUDY: Metastasis of cancer cells is an obstacle to the clinical treatment of cancer. We found that dense cultures made metastatic cancer cells more potent in terms of proliferation, migration, and invasion. The proteomic and bioinformatic analyses provided some valuable clues for further intensive studies about the effects of cell density on cancer cell aggressiveness, which were associated with events such as pre-mRNA splicing and RNA transport, focal adhesion and cytoskeleton reorganization, ribosome biogenesis, and transendothelial migration, or associated with proteins, such as JAM-1 and S100A11. This investigation gives us new perspectives to investigate the metastasis mechanisms related to the microenvironment of tumour sites.

UPLC-PDA-ESI-MS/MS analysis of compounds extracted by cardiac h9c2 cell from Polygonum orientale.

INTRODUCTION: A flavonoid-enriched extract (FEE) of Polygonum orientale was reported to show cardioprotective effect but only very few compounds were reported to contribute to the effect. Identification of compounds interacting with the target cardiac cell is important for the understanding of active compounds. OBJECTIVE: To develop an efficient method for the screening of potential active compounds directly acting on the target cardiac cell in FEE and to structurally characterise these compounds. METHODOLOGY: Flavonoid-enriched extract was prepared by extraction of the plant with water, addition of ethanol to the solution to remove polysaccharides and proteins, and removal of tannins by a polyamide column chromatography. Cell extraction was conducted on a cardiac h9c2 cell and the solution containing compounds released from the cell were desalted by solid phase extraction. Compounds present in the cell extract were detected by ultra-performance liquid chromatography (UPLC) and targeted multi-reaction monitoring (MRM), while their structures were characterised by UPLC-photodiodide array (PDA)-electrospray ion source (ESI)-MS/MS investigations of the FEE. RESULTS: Twenty-three potentially active phenolics including ten flavonoid C-glycosides and six flavonoid O-glycosides have been identified from the 40 compounds screened in the cell extract. Among these compounds, three were new and nine were identified from this plant for the first time. Strategies for the structural characterisation of flavonoid glycosides were also discussed. CONCLUSION: The study has shown that FEE contains the flavonoid as its major principles and the coupling of UPLC-PDA-ESI-MS/MS and targeted UPLC-MRM with target cell extraction is an efficient method for the screening and structural characterisation of potential active compounds.

[Expression and localization of endogenous C-reactive protein in THP-1 monocytes and LO2 hepatocytes].

OBJECTIVE: To observe the expression and localization of endogenous C-reactive protein (CRP) in cells from different tissues under different conditions. METHODS: Macrophages differentiated from THP-1 monocytes with phorbol ester (PMA) induction and human LO2 hepatocytes were stimulated with lipopolysaccharide (LPS). The culture supernatant of the LPS-stimulated THP-1 cells was collected and added into LO2 cell culture, and after incubation, the cells were lysed to extract the proteins for SDS-PAGE and Western blotting. The stimulated cells were also examined immunocytochemically for CRP expression. RESULTS: Western blotting detected CRP in both of the unstimulated cell lysates, but in neither of the two cell supernatants. After LPS stimulation, CRP expression was significantly increased in the cell lysate of THP-1 cells with also a small amount present in the supernatant, but CRP expression and release in the LO2 cells showed no significant variation. Treatment of the LO2 cells with the culture supernatant of LPS-stimulated THP-1 cells resulted in positivity of CRP in the cell lysate and the culture supernatant. Immunocytochemistry identified CRP expression throughout the THP-1 cell body (most obvious in the nuclei), which increased after LPS stimulation. In LO2 hepatocytes, CRP expression was found only outside the nuclei and increased after stimulation with the culture supernatant of LPS-treated THP-1 cells, especially obvious around the membrane. CONCLUSION: CRP can not be up-regulated directly by LPS treatment in LO2 cells, but can be induced by certain cytokines (IL-6) secreted from LPS-stimulated THP-1 cells. The localization of CRP represents the characteristics of secreted protein in LO2 cells, but in THP-1 cells, CRP is found mainly in the cell nuclei.

[The application of two-dimensional liquid phase chromatography to separation of total protein of Leymus chinensis shoot].

The total proteins of Leymus chinensis were extracted from eight-week-old seedlings grown in the greenhouse by TCA-acetone precipitation method. After the lysis buffer was replaced by the start buffer, proteins were fractionated along the first dimension using chromatofocusing (CF). Subsequently the fractions with pI values between 8.5 and 4.0 collected after the first dimension separation were further fractionated by nonporous silica reverse-phase high-performance liquid chromatography (NPS-RP-HPLC, HPRP). With ProteoVue software the pI/UV map was generated to show the protein expression profile of Leymus chinensis. Some experiments were tested to optimize the fraction procedure. Three different elution gradients were employed to get the optimal chromatogram. Comparison of the protein expression pattern between 2D-PAGE and 2D-LC indicated that 2D-LC was a powerful tool in protein fraction. Reproducibility and veracity of the protein patterns were confirmed in different injections of the same sample. A method to fractionate the total protein of Leymus chinensis shoot with two-dimensional liquid chromatography (2D-LC) was founded.

[Two-dimensional liquid chromatographic fractionation of mouse liver phosphoproteome].

OBJECTIVE: To fractionate mouse liver phosphoproteome by two-dimensional liquid chromatography. METHODS: The phosphoproteins were extracted from the lysates of normal mouse livers with phosphate metal affinity chromatography resin. The phosphoproteins were exchanged by the initial buffer and separated by chromatofocusing in the first dimension. The fractions with pH value between 8.5 and 4.0 were separated by non-porous silica reverse-phase high-performance liquid chromatography. Finally, the UV maps were converted into gel maps by ProteoVue software. RESULTS: The phosphoproteins of mouse liver were successfully extracted and fractionated by two-dimensional liquid chromatographic fractionation after concentration and desalting. The pI/UV map of mouse liver phospho-proteomic was obtained successfully. There were 16 fractions with pH between 8.5 and 4.0 after chromatofocusing in the first dimension and the UV maps of each fraction were converted into pI/UV gel maps. CONCLUSION: Combination of phosphoprotein enrichment and two-dimensional liquid chromatographic fractionation is an effective approach of phosphoproteomic studies.