Raf/MEK/ERK Signaling Pathway Is Involved in the Inhibition of Glioma Cell Proliferation and Invasion in the Ketogenic Microenvironment

OBJECTIVE

A high-fat, low-carbohydrate ketogenic diet has been used to treat malignant glioma, in which the Raf/MEK/ERK signaling pathway is overactivated. However, whether the Raf/MEK/ERK signaling pathway is involved in the therapeutic effect of ketone bodies remains unknown. In this study, we investigated the effects of a major ketone body, 3-hydroxybutyric acid (3-HBA), on the proliferation and metastasis of malignant glioblastoma cells and the underlying mechanism.

METHODS

Two human malignant glioblastoma cell lines (U87 and U251) were treated with different concentrations of 3-HBA with or without the Raf inhibitor PAF C-16 for 24 h. Cell proliferation, cell cycle, cell invasion, and phospholipase D1 (PLD1) activity were determined. Protein and gene expression levels of Raf/MEK/ERK signaling pathway members were examined.

RESULTS

3-HBA significantly decreased cell proliferation, invasion, and intracellular PLD1 activity in both U87 and U251 glioblastoma cell lines. 3-HBA treatment significantly increased the proportion of cells in the G1 phase and decreased the proportion of cells in S phase in U87 cells. In the U251 line, the proportion of treated cells in S phase was increased and proportion of cells in G2 was decreased. 3-HBA treatment also significantly decreased the protein expression levels of Raf, MEK, p-MEK, ERK, p-ERK, and PLD1 while increasing p53 expression; an effect that was similar to treatment with the Raf inhibitor. Co-treatment of 3-HBA with the Raf inhibitor further enhanced the effects of the 3-HBA in both cell lines.

CONCLUSION

We confirmed that a ketogenic microenvironment can inhibit glioma cell proliferation and invasion by downregulating the expression of PLD1 through the Raf/MEK/ERK signaling pathway.

Benign esophageal stricture model construction and mechanism exploration

Esophageal stricture is a debilitating condition that negatively impacts patients' quality of life after undergoing endoscopic mucosal resection (EMR). Despite its significance, this disease remains underexplored due to the lack of a stable animal model. Under direct visualization with choledochoscopy, we retrogradely damaged the esophageal mucosal layer through the gastrostomy to create a rat model of esophageal stricture. The development of histological defects in the mucosal layer was assessed over a 2-week period after model induction. Then the models were evaluated using X-ray barium radiography, Hematoxylin-Eosin, Masson's trichrome, Sirius red, and Victoria blue staining, multiphoton microscopic imaging. Additionally, the molecular mechanisms of esophageal stricture were explored by conducting RNA transcriptome sequencing, PCR, immunohistochemistry, and immunofluorescence staining. We successfully established fifteen rat models of esophageal stricture by injuring the mucosal layer. In the model group, the mucosal defect initially occurs and subsequently repaired. The epithelium was absent and was plastically remodeled by collagen during the acute inflammatory phase (Day 1), proliferation phase (Day 7), anaphase of proliferation (Day 10), and plastic remodeling phase (Day 14). We observed increased expression of COL1A1, acta2, FGF, IL-1, and TGF-β1 pathway in the model group. We established a highly repeatable rat model of esophageal stricture, and our results suggest that the mucosal defect of the esophagus is a critical factor in esophageal stricture development, rather than damage to the muscularis layer. We identified Atp4b, cyp1a2, and gstk1 as potential targets for treating esophageal stricture, while the TGF-β pathway was found to play an important role in its development.

Development of an immune-related prognostic biomarker for triple-negative breast cancer

Purpose: Oncology studies employing digital dissection methodologies have provided some insight on the biological features of tumor microenvironment of Triple-negative breast cancer (TNBC), but molecular diagnostics rarely have therapeutic impact. We aimed to identify a novel prognostic biomarker to investigate immune characteristics of TNBC using transcriptomic features.Patients and Methods: We extracted whole transcriptome from breast cancer tissue of 30 TNBC patients and then used bioinformatics approaches to characterize the different immune cell contents in tumor tissue and para-cancerous tissue. We extract 2 indicators to describe the major differences in immune infiltration in the microenvironment between tumor tissue and para-cancerous tissue. We then combined the 2 indicators that represent the levels of increased and decreased infiltration in each sample to obtain the Immune Infiltration Score (IIS). Then we compared the tumor-infiltrating immune cell contents and immune infiltrating status in TNBC samples with CIBERSORT and ESTIMATE score to validate the IIS. Finally, 132 TNBC patients from the Cancer Genome Atlas program (TCGA) dataset was used to validate the predictive power of IIS.Results: 4 types of upregulated and 4 types of downregulated immune cells were identified in the tumor tissue samples of the TNBC patients. Then we developed a novel biomarker, IIS. Results showed that IIS score can clearly separate cancer and para-cancerous tissue. Using the same cutoff value of 0 in the TNBC-TCGA cohort, we show that those patients with a higher IIS had significantly higher PD-L1 expression and shorter progression-free survival time than those with a lower IIS value, indicating IIS score can be generalized to other TNBC datasets.Conclusion: we explored the immune infiltration landscape in 30 TNBC patients and provided IIS as a novel and reliable biomarker to evaluate the progression-free survival and prognosis of the TNBC patients.

Protective effect of the new prepared Atractylodes macrocephala Koidz polysaccharide on fatty liver hemorrhagic syndrome in laying hens

Fatty liver hemorrhage syndrome (FLHS) is the most common noninfectious cause of death in backyard chickens worldwide, which can cause a sudden drop in egg production in the affected flocks and cause huge losses to the laying hens breeding industry. In this study, we prepared polysaccharide from Atractylodes macrocephala Koidz (PAMK) by one-step alcohol precipitation. The structural analysis found that PAMK with a molecular weight of 2.816 × 10³ Da was composed of glucose and mannose, in a molar ratio of 0.582 to 0.418. Furthermore, we investigated the hepatoprotective effects of PAMK on high-energy and low-protein (HELP) diet-induced FLHS in laying hens. The results showed that the hens' livers of the HELP diet showed yellowish-brown, greasy, and soft, whereas the supplement of PAMK (200 mg/kg or 400 mg/kg) could alleviate such pathological changes. The liver index, the abdominal fat percentage, and liver injury induced by the HELP diet were reduced in PAMK (200 mg/kg or 400 mg/kg). Supplementing 200 mg/kg or 400 mg/kg PAMK showed improvements of the antioxidant capacity in laying hens. Furthermore, we found that the HELP diet increased the expression of hepatic lipogenesis genes and decreased the expression of fatty acid β-oxidation genes, which could be reversed by 200 mg/kg or 400 mg/kg PAMK supplementation. Nevertheless, there is no difference between the addition of 40 mg/kg PAMK and the HELP group. Collectively, these results showed that PAMK supplements could ameliorate HELP diet-induced liver injury through regulating activities of antioxidant enzymes and hepatic lipid metabolism. Therefore, PAMK could be a potential feedstuff additive to alleviate FLHS in laying hens.

[Research on network pharmacology of Acori Tatarinowii Rhizoma combined with Curcumae Radix in treating epilepsy]

The chemical constituents and action targets of Acori Tatarinowii Rhizoma and Curcumae Radix were screened by network pharmacological method,and the mechanism of the combination of Acori Tatarinowii Rhizoma and Curcumae Radix in the treatment of epilepsy was analyzed. All chemical constituents of Acori Tatarinowii Rhizoma and Curcumae Radix were retrieved by TCMSP,and their action targets were screened. Component target PPI network was constructed. Epilepsy-related genes were retrieved from PharmGkb database,and PPI networks of disease targets were drawn by Cytoscape software. Cytoscape software was used to merge the network,screen the core network,and further analyze the gene GO function and KEGG pathway enrichment,which was verified by experimental research. One hundred and five chemical constituents of Acori Tatarinowii Rhizoma and 222 chemical constituents of Curcumae Radix were retrieved. Nineteen compounds were selected as candidate compounds according to OB and DL values. Among them,4 chemical constituents of Acori Tatarinowii Rhizoma and 15 chemical constituents of Curcumae Radix were found. A total of 88 target proteins were retrieved by retrieving TCMSP data,and PPI network was constructed. Through PharmGkb database,29 epilepsy-related genes were retrieved and disease target network was established. Cytoscape software and plug-ins were used for network merging and core network screening,and 69 genes were screened out. Through GO function analysis and KEGG pathway analysis,the mechanism of anti-epilepsy is related to prolactin signaling pathway,HTLV-Ⅰ infection signaling pathway,MAPK signaling pathway and herpes simplex infection signaling pathway. Further experimental verification showed that the serum prolactin level in epileptic rats was significantly increased. The neurons in hippocampal CA1 area degenerated,necrotized and lost 24 hours after epileptic seizure,and some neuron interstitial edema occurred. The possible mechanism of compatibility of Acori Tatarinowii Rhizoma and Curcumae Radix is related to serum prolactin level,MAPK signaling pathway,HTLV-Ⅰ infection and herpes simplex infection. The analysis may be related to viral encephalitis caused by HTLV-Ⅰ virus and herpes simplex infection,which damages nerve cells and causes seizures.

[Mechanism of Acori Tatarinowii Rhizoma-Curcumae Radix treating depression based on network pharmacology]

To screen the target for the treatment of depression of Acori Tatarinowii Rhizoma and Curcumae Radix using the pharmacological method of network pharmacology, in order to define the mechanism of antidepressant effect. Pharmacological data (TCMSP) of forall of chemical constituents of Acori Tatarinowii Rhizoma and Curcumae Radix through traditional Chinese medicine system (TCMSP) was retrieved to screen the target sites, and construct the component target PPI network. PharmGkb database was retrieved for the genes associated with depression, and the disease target was mapped using the Cytoscape software. The Cytoscape software was used to merge the network and filter the core network, and further analyze the gene GO function and the KEGG pathway enrichment. There were 62 nodes and 87 connections on the target PPI network. The PPI network had 1 289 nodes and 17 714 connections. After the network merged, the component-target-disease network had 1 337 nodes and 17 801 connections. Through screening the core network, there were 63 nodes and 935 connections, which represented the complex interaction between the components and the target. Gene GO functional analysis suggested that biological processes, molecular functions and cell components were involved. Gene KEGG pathway enrichment analysis showed associations with misfolded protein, secretory hormone secretion, and apoptosis of hippocampal neurons. The possible mechanism for treating depression is the adjustment of wrong folding protein, sex hormone secretion and apoptosis of hippocampal neurons.

Diaquabis[3-(4-methylphenyl)-5-(pyridin-2-yl-κN)-1H-1,2,4-triazolato-κN 1]cadmium trihydrate

In the title compound, [Cd(C14H11N4)2(H2O)2]·3H2O, the CdII cation is chelated by two 3-(4-methylphenyl)-5-(pyridin-2-yl)-1H-1,2,4-triazolate anions and coordinated by two water molecules in a distorted N4O2 octahedral geometry. Within the organic ligands, the methylphenyl rings are twisted with respect to the mean planes of chelating rings by 18.31 (16) and 14.89 (15)°. In the crystal, extensive O—H...O and O—H...N hydrogen bonds and weak C—H...O interactions link the molecules into a three-dimensional supramolecular architecture.

[Diversity of intestinal microflora in patients with depression after stroke]

OBJECTIVE

To investigate the changes in the population and distribution intestinal microflora and their relationship with depression in post-stroke patients.

METHODS

Fecal specimens were obtained from 32 patients with post-stroke depression and 30 healthy adults for gene sequencing of 16S RNA V3 region of the intestinal microorganism using Roche/45 high-throughput sequencing platform.

RESULTS

The genus and species of intestinal bacteria showed significant differences between the post-stroke patients and health adults.

CONCLUSION

Significant changes in the structure of intestinal flora occur in patients with post-stroke depression.

Expression of nerve growth factor messenger RNA in pancreatic cancer tissues in Sprague Dawley rats

AIM: To establish a model of pancreatic cancer in Sprague-Dawley(SD)rats and to explore the expression and its significance of nerve growth factor(NGF)mRNA in pancreatic cancer and non-cancer tissues.

METHODS: Ninety rats were randomly divided into A (n = 40), B (n = 40) and C (n = 10) group. For group A and B, dimethylbenzanthrancene (DMBA) was directly implanted into the parenchyma of the rat pancreas to establish pancreatic cancer model. The rats in group B were treated with trichostatin(TSA). The rats in group C served as the controls. The rats were executed within 3-5 mo, and the carcinogenesis of the rats was observed by pathological methods. In situ hybridization was used to detect the expression of NGF mRNA in the formalin-fixed and routinely paraffin-embedded sections of pancreatic cancer and non-cancer tissues.

RESULTS: The prevalence rate of pancreatic cancer in group A was 48.7%(18/37) within 3-5 mo, 28.6%(2/7) at mo, 40.0%(4/10) at 4 mo and 60%(12/20) at 5 mo (P > 0.05), and that in group B was 33.3%(12/36), 16.7%(1/6), 30.0%(3/10) and (40.0%)8/20, respectively (P > 0.05). The prevalence rate in group A was higher than that of group B (P > 0.05). The diameters of tumor mass in group A were significantly larger than those in group B (group A: 0.5-1.0 cm 7 cases, 1.0-2.0 cm 10 cases, > 2 cm 1 case vs group B: 0.5-1.0 cm 9 case, 1.0-2.0 cm 2 cases, >2.0 cm 1 case, P < 0.05). No tumor formed in the pancreas of the rats in group C or in other main organs of the rats in group A and B. The positive rate of NGF mRNA expression in the pancreatic ductal cancer tissues was significantly higher than that in non-cancer tissues (67.9% vs 18.6%, P < 0.01), and severely atypical hyperplasia was observed in the positive non-cancer pancreatic tissues of ductal epithelium. The positive rate of NGF mRNA expression in ductal adenocarcinoma was markedly higher in group A than that in group B (P = 0.052). The positive rate of NGF mRNA in the rats with tumor maximal diameter ≤ 1.0 cm was lower than that in the ones with tumor maximal diameter > 1.0 cm (P > 0.05).

CONCLUSION: Direct implantation of DMBA in the parenchyma of pancreas can induce pancreatic cancer with a high occurrence rate in a short time. NGF may play an important role in the carcinogenesis of pancreatic cancer. TSA can inhibit the occurrence and progression of pancreatic cancer by inhibiting NGF expression.

[Preventive effect of 5-fluorouracil on post-ERCP pancreatitis]

OBJECTIVE

To investigate the preventive effect of 5-fluorouracil (5-FU) on post-ERCP (endoscopic retrograde cholangiopancreatography) hyperamy-lasemia and pancreatitis.

METHODS

One hundred and sixty patients who underwent ERCP were divided at random into 2 groups: group A (n = 80) was given meglumine diatrizoate with 5-FU; and group B (n = 80) was used contrast medium without 5-FU. Blood was drawn in each group the day before, 6 hours and 24 hours following ERCP for amylase.

RESULTS

Post-ERCP hyperamylasemia occurred in 9 patients in group A (11. 25%) and 45 in B (56.25%). The difference of both groups was notable. Pancreatitis ensued in 2 instances in group A (2.50%) and 8 in group B (10.00%). Their difference was significant.

CONCLUSION

5-FU added in meglumine diatrizoate is helpful to prevent post-ERCP hyperamylasemia and pancreatitis.

Calmodulin-independent coordination of Ras and extracellular signal-regulated kinase activation by Ras-GRF2

Ras-GRF2 (GRF2) is a widely expressed, calcium-activated regulator of the small-type GTPases Ras and Rac. It is a multidomain protein composed of several recognizable sequence motifs in the following order (NH(2) to COOH): pleckstrin homology (PH), coiled-coil, ilimaquinone (IQ), Dbl homology (DH), PH, REM (Ras exchanger motif), PEST/destruction box, Cdc25. The DH and Cdc25 domains possess guanine nucleotide exchange factor (GEF) activity and interact with Rac and Ras, respectively. The REM-Cdc25 region was found to be sufficient for maximal activation of Ras in vitro and in vivo caused Ras and extracellular signal-regulated kinase (ERK) activation independent of calcium signals, suggesting that, at least when expressed ectopically, it contains all of the determinants required to access and activate Ras signaling. Additional mutational analysis of GRF2 indicated that the carboxyl PH domain imparts a modest inhibitory effect on Ras GEF activity and probably normally participates in intermolecular interactions. A variant of GRF2 missing the Cdc25 domain did not activate Ras and functions as an inhibitor of wild-type GRF2, presumably by competing for interactions with molecules other than calmodulin, Ras, and ligands of the PH domain. The binding of calmodulin was found to require several amino-terminal domains of GRF2 in addition to the IQ sequence, and no correlation between calmodulin binding by GRF2 and its ability to directly activate Ras and indirectly stimulate the mitogen-activated protein (MAP) kinase ERK in response to calcium was found. The precise role of the GRF2-calmodulin association, therefore, remains to be determined. A GRF2 mutant missing the IQ sequence was competent for Ras activation but failed to couple this to stimulation of the ERK pathway. This demonstrates that Ras-GTP formation is not sufficient for MAP kinase signaling. We conclude that in addition to directly activating Ras, GRF2, and likely other GEFs, promote the assembly of a protein network able to couple the GTPase with particular effectors.

The exchange factor Ras-GRF2 activates Ras-dependent and Rac-dependent mitogen-activated protein kinase pathways

Ras and Rac are membrane-associated GTPases that function as molecular switches activating intracellular mitogen-activated protein kinase (MAPK) cascades and other effector pathways in response to extracellular signals [1]. Activation of Ras and Rac into their GTP-bound conformations is directly controlled by specific guanine-nucleotide exchange factors (GEFs), which catalyze GDP release. Several Ras-specific GEFs that are related to the budding yeast protein Cdc25p have been described, whereas GEFs for Rac-related GTPases contain a region that is homologous to the oncoprotein DbI [2-3]. The Ras-GRF1 and Ras-GRF2 proteins, which couple Ras activation to serpentine receptors and calcium signals, contain both Cdc25 and DbI homology (DH) regions [3-4]. Here, we demonstrate that Ras-GRF2 is a bifunctional signaling protein that is able to bind and activate Ras and Rac, and thereby coordinate the activation of the extracellular-signal-regulated kinase (ERK) and stress-activated protein kinase (SAPK) pathways.

Cloning and characterization of Ras-GRF2, a novel guanine nucleotide exchange factor for Ras

Conversion of Ras proteins into an activated GTP-bound state able to bind effector proteins is catalyzed by specific guanine nucleotide exchange factors in response to a large number of extracellular stimuli. Here we report the isolation of mouse cDNAs encoding Ras-GRF2, a multidomain 135-kDa protein containing a COOH-terminal Cdc25-related domain that stimulates release of GDP from Ras but not other GTPases in vitro. Ras-GRF2 bound specifically to immobilized Ras lacking bound nucleotides, suggesting stabilization of the nucleotide-free form of Ras as a mechanism of catalyzing nucleotide exchange. The NH2-terminal region of Ras-GRF2 is predicted to contain features common to various signaling proteins including two pleckstrin homology domains and a Dbl homology region. Ras-GRF2 also contains an IQ motif which was required for its apparent constitutive association with calmodulin in epithelial cells ectopically expressing Ras-GRF2. Transient expression of Ras-GRF2 in kidney epithelial cells stimulated GTP binding by Ras and potentiated calcium ionophore-induced activation of mitogen-activated protein kinase (ERK1) dependent upon the IQ motif. Calcium influx caused Ras-GRF2 subcellular localization to change from cytosolic to peripheral, suggesting a possible mechanism for controlling Ras-GRF2 interactions with Ras at the plasma membrane. Epithelial cells overexpressing Ras-GRF2 are morphologically transformed and grow in a disorganized manner with minimal intercellular contacts. Northern analysis indicated a 9-kb GRF2 transcript in brain and lung, where p135 Ras-GRF2 is known to be expressed, and RNAs of 12 kb and 2.2 kb were detected in several tissues. Thus, Ras-GRF2 proteins with different domain structures may be widely expressed and couple diverse extracellular signals to Ras activation.