LAMC2 regulates the proliferation, invasion, and metastasis of gastric cancer via PI3K/Akt signaling pathway

OBJECTIVES

Gastric cancer (GC) is a prevalent malignant tumor widely distributed globally, exhibiting elevated incidence and fatality rates. The gene LAMC2 encodes the laminin subunit gamma-2 chain and is found specifically in the basement membrane of epithelial cells. Its expression is aberrant in multiple types of malignant tumors. This research elucidated a link between LAMC2 and the clinical characteristics of GC and investigated the potential involvement of LAMC2 in GC proliferation and advancement.

MATERIALS AND METHODS

LAMC2 expressions were detected in GC cell lines and normal gastric epithelial cell lines via qRT-PCR. Silencing and overexpression of the LAMC2 were conducted by lentiviral transfection. A xenograft mouse model was also developed for in vivo analysis. Cell functional assays were conducted to elucidate the involvement of LAMC2 in cell growth, migration, and penetration. Further, immunoblotting was conducted to investigate the impact of LAMC2 on the activation of signal pathways after lentiviral transfection.

RESULTS

In the findings, LAMC2 expression was markedly upregulated in GC cell lines as opposed to normal gastric epithelial cells. In vitro analysis showed that sh-LAMC2 substantially inhibited GC cell growth, migration, and invasion, while oe-LAMC2 displayed a contrasting effect. Xenograft tumor models demonstrated that oe-LAMC2 accelerated tumor growth via high expression of Ki-67. Immunoblotting analysis revealed a substantial decrease in various signaling pathway proteins, PI3K, p-Akt, and Vimentin levels upon LAMC2 knockdown, followed by increased E-cadherin expression. Conversely, its overexpression exhibited contrasting effects. Besides, epithelial-mesenchymal transition (EMT) was accelerated by LAMC2.

CONCLUSION

This study provides evidence indicating that LAMC2, by stimulating signaling pathways, facilitated EMT and stimulated the progression of GC cells in laboratory settings and mouse models. Research also explored that the abnormal LAMC2 expression acts as a biomarker for GC.

Analyzing the expression and clinical significance of CENPE in gastric cancer

BACKGROUND

Gastric cancer (GC) is a prevalent type of malignant gastrointestinal tumor. Many studies have shown that CENPE acts as an oncogene in some cancers. However, its expression level and clinical value in GC are not clear.

METHODS

Obtaining clinical data information on gastric adenocarcinoma from TCGA and GEO databases. The gene expression profiling interaction analysis (GEPIA) was used to evaluate the relationship between prognosis and CENPE expression in gastric cancer patients. Utilizing the UALCAN platform, the correlation between CENPE expression and clinical parameters was examined. Functions and signaling pathways of CENPE were analyzed using the Gene Ontology (GO), the Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA). The association between immunological infiltrating cells and CENPE expression was examined using TIMER2.0. Validation was performed by real-time quantitative PCR (qPT-PCR) and immunohistochemical analysis.

RESULTS

According to the analysis of the GEPIA database, the expression of CENPE is increased in gastric cancer tissues compared to normal tissues. It was also found to have an important relationship with the prognosis of the patient (p<0.05). The prognosis was worse and overall survival was lower in individuals with increased expression of CENPE. In line with the findings of the GEPIA, real-time fluorescence quantitative PCR (qPT-PCR) confirmed that CENPE was overexpressed in gastric cancer cells. Furthermore, It was discovered that H. pylori infection status and tumor grade were related to CENPE expression. Enrichment analysis revealed that CENPE expression was linked to multiple biological functions and tumor-associated pathways. CENPE expression also correlated with immune-infiltrating cells in the gastric cancer microenvironment and was positively connected to NK cells and mast cells. According to immunohistochemical examination, paracancerous tissues had minimal expression of CENPE, but gastric cancer showed significant expression of the protein.

CONCLUSIONS

According to our findings, CENPE is substantially expressed in GC and may perhaps contribute to its growth. CENPE might be a target for gastric cancer therapy and a predictor of a bad prognosis.

RAE1 promotes gastric carcinogenesis and epithelial-mesenchymal transition

AIMS

The purpose of this study was to explore the role of RAE1 in the invasion and metastasis of gastric cancer (GC) cells.

MATERIALS AND METHODS

RAE1 expression in GC cells was determined by reverse-transcription polymerase chain reaction (qRT-PCR) and Western blotting (WB). Cell models featuring RAE1 gene silencing and overexpression were constructed by lentiviral transfection; The proliferation, migration, and invasion ability of cells were detected by cell counting, colony formation assay, would healing assay, and transwell invasion and migration test. WB analysis of ERK/MAPK signaling pathway (ERK1/2, p-ERK1/2, c-Myc) and EMT-related molecules (ZEB1, E-cadherin, N-cadherin, and Vimentin).

RESULTS

The expression level of RAE1 in GC was notably higher than in adjacent tissues. Elevated RAE1 expression correlated with an unfavorable prognosis for GC patients. Knockdown of RAE1, as compared to the control group, resulted in a significant inhibition of proliferation, migration, and invasion abilities in GC cell lines. Furthermore, RAE1 knockdown led to a substantial decrease in the expression of N-cadherin, vimentin, ZEB1, p-ERK1/2, and c-Myc proteins, coupled with a marked increase in E-cadherin expression. The biological effects of RAE1 in GC cells were effectively reversed by the inhibition of the ERK/MAPK signaling pathway using SCH772984. Additionally, RAE1 knockdown demonstrated a suppressive effect on GC tumor size in vivo. Immunohistochemistry (IHC) results revealed significantly lower expression of Ki-67 in RAE1 knockout mice compared to the control group.

CONCLUSIONS

RAE1 promotes GC cell migration and invasion through the ERK/MAPK pathway and is a potential therapeutic target for GC therapy.

Synthesis, Antiviral, and Antibacterial Activity of the Glycyrrhizic Acid and Glycyrrhetinic Acid Derivatives

Glycyrrhizic acid and its primary metabolite glycyrrhetinic acid, are the main active ingredients in the licorice roots (glycyrrhiza species), which are widely used in several countries of the world, especially in east asian countries (China, Japan). These ingredients and their derivatives play an important role in treating many diseases, especially infectious diseases such as COVID-19 and hepatic infections. This review aims to summarize the different ways of synthesising the amide derivatives of glycyrrhizic acid and the main ways to synthesize the glycyrrhitinic acid derivatives. Also, to determine the main biological and pharmacological activity for these compounds from the previous studies to provide essential data to researchers for future studies.

60 dB high-extinction auto-configured Mach-Zehnder interferometer

Imperfections in integrated photonics manufacturing have a detrimental effect on the maximal achievable visibility in interferometric architectures. These limits have profound implications for further technological developments in photonics and in particular for quantum photonic technologies. Active optimization approaches, together with reconfigurable photonics, have been proposed as a solution to overcome this. In this Letter, we demonstrate an ultrahigh (>60  dB) extinction ratio in a silicon photonic device consisting of cascaded Mach-Zehnder interferometers, in which additional interferometers function as variable beamsplitters. The imperfections of fabricated beamsplitters are compensated using an automated progressive optimization algorithm with no requirement for pre-calibration. This work shows the possibility of integrating and accurately controlling linear-optical components for large-scale quantum information processing and other applications.

Cumulative methylation alternations of gene promoters and protein markers for diagnosis of epithelial ovarian cancer

DNA methylation plays an important role in carcinogenesis and cancer development. In this study, we examined gene methylation in epithelial ovarian cancer (EOC) using cationic conjugated polymer (CCP)-based fluorescence resonance energy transfer (FRET) to evaluate the application of cumulative methylation alternations of genes associated with cancer antigen 125 for early cancer diagnosis. The methylation status of 3 genes (Ras association domain family 1 isoform A, RASSF1A; opioid-binding protein/cell adhesion molecule, OPCML; homeobox A9, HOXA9) were examined and compared in 35 EOC samples and 11 normal ovarian tissue samples using CCP-based FRET. Gene methylation levels were clustered into 3 sections and assigned a value; values for the 3 genes were summed. Although methylation of the OPCML gene was significantly associated with stage, histological types, grade, and ascites and that of RASSF1A and HOXA9 was not, the sum for the 3 genes was significantly associated with stage and ascites. The sum showed higher sensitivity (85.7%) and specificity (100%) for discriminating EOC from normal ovarian tissues than did the methylation status of RASSF1A, OPCML, and HOXA9 (48.6, 77.1, 77.1, and 100, 88.1, 100%, respectively). Combining cancer antigen 125 levels with the sum increased the sensitivity to 94.3%. The detection and analysis of a panel of genes' methylation status with the CCP-based FRET technique may be useful for diagnosis and screening of EOC; the associated cancer antigen 125 can be used to increase diagnostic sensitivity.

Molecular basis for the insulinomimetic effects of C-peptide

AIMS/HYPOTHESIS

C-peptide, released by the beta-cells of pancreatic islets, elicits salutary responses in Type I (insulin-dependent) diabetes mellitus but the molecular mechanisms behind these effects are not known. We assessed whether synthetic rat C-peptide stimulates insulin-like cellular effects in a classic insulin target tissue.

METHODS

To clarify the molecular mechanisms involved in several insulinomimetic actions, we investigated the effect of C-peptide on the insulin signalling pathway in rat skeletal muscle cells. We used L6 myoblasts and myocytes to measure the effects of C-peptide or insulin or both on glycogen synthesis and amino acid uptake. We also studied the effects of C-peptide on insulin receptor autophosphorylation, its tyrosine kinase activity, phosphorylation of IRS-1, PI 3-kinase, Akt, p90Rsk, MAPK, and GSK3 in these cells.

RESULTS

In L6 cells, physiological concentrations of C-peptide (0.3-3 nmol/l) significantly activated insulin receptor tyrosine kinase, IRS-1 tyrosine phosphorylation, PI 3-kinase activity, MAPK phosphorylation, p90Rsk, and GSK3 phosphorylation. A scrambled C-peptide sequence - the control - showed no effects. Wortmannin blocked C-peptide-induced glycogen synthesis while pertussis toxin had no effect. Only submaximal insulin concentrations (up to 10 nmol/l) combined with submaximal C-peptide concentrations led to additive effects.

CONCLUSION/INTERPRETATION

C-peptide added to the maximal insulin dose (100 nmol/l) did not increase the effect of insulin alone. We thus conclude that the same signalling elements are used by both ligands. However, the lack of Akt activation by C-peptide and the bell-shaped dose response induced by C-peptide indicate that C-peptide has some effects by another distinct mechanism. We speculate that C-peptide could modulate the metabolic effects of insulin by enhancing them at low hormone concentrations and dampening them at high hormone concentrations.

C-peptide attenuates protein tyrosine phosphatase activity and enhances glycogen synthesis in L6 myoblasts

Recent studies suggest that C-peptide might play a role in a broad range of biological activities. We have provided evidence that C-peptide stimulates glycogen synthesis in insulin-responsive rat skeletal muscle cells in a dose-related manner. To explore the mechanism by which C-peptide exerts this insulinomimetic effect, here we report the effect of C-peptide on protein tyrosine phosphatase (PTP) activity and phosphorylation of the insulin receptor and insulin receptor substrate-1 (IRS-1). C-peptide inhibited PTP activity in a dose-dependent manner. A reverse bell-shaped dose-response curve was shown with the maximum inhibition of PTP activity at a concentration of 3 nM of C-peptide, which is the same concentration achieving the maximum stimulatory effect on glycogen synthesis. In association with the PTP inhibition by C-peptide, autophosphorylation of the insulin receptor and activation of IRS-1 were enhanced. These results suggest that C-peptide signal transduction may crosstalk with the insulin signaling pathway at the level of the insulin receptor.

Adjuvant-induced improvement of glucose intolerance in type 2 diabetic KK-Ay mice through interleukin-1 and tumor necrosis factor-alpha

We reported that administration of complete Freund's adjuvant (CFA) improved glucose tolerance test (GTT) results in obese diabetic KK-Ay mice. In this study, we investigated its mechanism. An injection with CFA remarkably improved GTT for more than a week in KK-Ay mice, although insulin response was not changed compared with saline controls. The hypoglycemic effect of insulin was significantly, but partially, potentiated in the CFA-treated mice compared with the controls, suggesting that CFA stimulated insulin-mediated and non-insulin-mediated glucose disposal. Improvement in the GTT with CFA was partially transferable to nontreated mice by peritoneal exudative cells, but not spleen or lymph node cells. Pretreatment with anti-interleukin (IL)-1 alpha and -1 beta antibodies or anti-tumor necrosis factor (TNF)-alpha antibody significantly abrogated the improvement in the GTT with CFA. The results indicate that CFA-induced improvement in glucose intolerance in KK-Ay mice was mediated at least by IL-1 and TNF-alpha.

Modulation of tumor necrosis factor-alpha production with anti-hypertensive drugs

It is well known that some anti-hypertensive drugs affect insulin sensitivity and that tumor necrosis factor-alpha (TNF-alpha) is a mediator of obesity-associated insulin resistance. In this study, we have investigated the effect of anti-hypertensive drugs, calcium (Ca) channel blockers (amlodipine, manidipine and nicardipine), an alpha(1)-blocker (doxazosin), a beta(1)-blocker (metoprolol), and a thiazide diuretic (hydrochlorothiazide), on lipopolysaccharide (LPS)-induced TNF-alpha production. TNF-alpha production, measured with a bioassay and an immunoassay, was evaluated both in vivo and in vitro, by utilizing mice and a human peripheral blood mononuclear cell culture, respectively. Nicardipine, or amlodipine, manidipine and doxazosin significantly inhibited TNF-alpha production in mice at doses more than one or ten times higher than those used clinically, respectively. On the other hand, metoprolol increased TNF-alpha production at doses of more than 10 times those used clinically, whereas hydrochlorothiazide did not alter production of the cytokine. The in vivo effects of these drugs were not necessary parallel to the in vitro effects. Because high doses of these drugs in mice correspond to clinical doses and effects in human, these actions may be related to beneficial and/or harmful effects of these drugs on TNF-alpha mediated diseases, including insulin resistance.

[Inhibited effect of phosphorylated insulin-like growth factor binding protein-1 on hepatoma cells in vitro]

OBJECTIVE

To elucidate the inhibited effect and regulated mechanism of IGFBp-1 on the carcinoma cells.

METHODS

The recombinant human IGF II (rhIGF II), phosphorylated and nonphosphorylated binding protein-1(pBp-1 and npBp-1) that were purified from pregnant woman's amnoitic fluid were used to cultivate cancer cells from 15 cases with hepatocellular carcinoma and ascites. The cell counting and MTT methods were used for determining the dynamics change of proliferation on HCC, and the in situ or dot hybridization with Digoxin label used for the expression of IGF II mRNA qualitatively and quantitatively at different times.

RESULTS

The cells grew more slowly, in pBp-1 group, than in control group at the same time, which began to decrease at two days(P < 0.05) by MTT. In situ hybridization showed that there are hybridization signal of IGF II mRNA in all groups during the culture, and scanning dot hybridization showed the OPTMD of IGF II mRNA in pBp-1 group was statistically different from control and other groups (P < 0.01), while in npBp-1 group there was no significant effect compared with other groups (P > 0.05).

CONCLUSION

The pBp-1 can inhibit the growth of hepatoma cells and the expression of IGF II mRNA, which may be regulated and inhibited by pBp-1.

Inhibition of tumor necrosis factor-alpha with anti-diabetic agents

It has recently been indicated that tumor necrosis factor-alpha (TNF-alpha) production is increased under chronic hyperglycemia and TNF-alpha has harmful effects on insulin sensitivity and possibly on chronic diabetic complications. Therefore it will be favorable for diabetes treatment if anti-diabetic agents also have anti-TNF-alpha activities. In this study, we have investigated effects of hypoglycemic sulfonylureas (gliclazide and glibenclamide) and a thiazolidinedione (troglitazone) on lipopolysaccharide-induced TNF-alpha production, which was evaluated by immunoassay and bioassay, in vivo using mice and partly in vitro using human peripheral blood mononuclear cells. Gliclazide significantly inhibited TNF-alpha production in vivo and also in vitro at a concentration of 10(-3) mol/l. However, glibenclamide had neither effect on TNF-alpha production nor action. On the other hand, troglitazone inhibited action rather than production of TNF-alpha in vivo. In vitro troglitazone (10(-4) mol/l) significantly reduced cytolytic activity of TNF-alpha against LM cells. These results indicate that gliclazide and troglitazone have inhibitory effect on TNF-alpha.

Inhibitory effect of troglitazone on diabetic neuropathy in streptozotocin-induced diabetic rats

Free-radical scavengers and inhibitors of tumour necrosis factor-alpha (TNF-alpha) such as N-acetylcysteine and pentoxifylline have been shown to inhibit the development of peripheral neuropathy in streptozotocin(STZ)-induced diabetic rats. In this study we examined the effect of troglitazone, an anti-diabetic thiazolidinedione, on diabetic neuropathy, since it also is a free-radical scavenger and a TNF-alpha inhibitor. Rats were fed powder chow mixed with troglitazone at 0.5% and 0.125% ad libitum. Although blood glucose concentrations were remarkably higher and body weight lower in diabetic than in nondiabetic rats, troglitazone had no effect on these throughout the 24-week experiment. Serum lipoperoxide concentrations, tibial nerve lipoperoxide content and serum TNF-alpha activity induced by lipopolysaccharide was increased in diabetic rats, but inhibited in troglitazone-treated rats. Motor nerve conduction velocity (MNCV) of the tibial nerve slowed in diabetic rats, compared with that in nondiabetic rats. On the other hand, the slowed MNCV was (p < 0.05-0.01) inhibited after weeks 12 and 16 of the experiment in diabetic rats treated with high and low doses of troglitazone, respectively. Morphometric analysis showed that troglitazone suppressed the decrease of the myelinated fibre area (p < 0.05), axon/myelin ratio (p < 0.01) and fascicular area (p < 0.05) and suppressed the increase of myelinated fibre density (p < 0.001) in diabetic rats. These results indicate that troglitazone has a beneficial effect on peripheral neuropathy in STZ-induced diabetic rats irrespective of blood glucose concentrations.

Gliclazide inhibits diabetic neuropathy irrespective of blood glucose levels in streptozotocin-induced diabetic rats

N-acetylcysteine and pentoxifylline, free radical scavengers and inhibitors of tumor necrosis factor-alpha (TNF-alpha) production, inhibit the development of peripheral neuropathy in streptozotocin (STZ)-induced diabetic rats. This study was designed to elucidate the effect of gliclazide, an oral hypoglycemic sulfonylurea, on diabetic neuropathy, because it has been indicated to be a free radical scavenger and TNF-alpha inhibitor. Rats were fed with powder chow mixed with gliclazide or glibenclamide as a control ad libitum. Blood glucose levels and body weight were remarkably higher and lower in diabetic than in nondiabetic rats, respectively, while gliclazide and glibenclamide had no effect on these in both diabetic and nondiabetic rats throughout a 24-week experiment. Serum lipoperoxide levels and lipopolysaccharide (LPS)-induced serum TNF-alpha activities were significantly increased in diabetic rats, whereas these were significantly inhibited in gliclazide-treated rats. Motor nerve conduction velocity (MNCV) of the tibial nerve significantly slowed in diabetic rats compared with nondiabetic rats. On the other hand, the slowed MNCV was significantly inhibited in gliclazide-treated diabetic rats after 16 experimental weeks. Morphometric analysis showed that gliclazide prevented decreased myelinated fiber area (P < .05), increased fiber density (P < .001), and decreased axon/myelin ratio (P < .05) in diabetic rats. Glibenclamide treatment did not affect serum lipoperoxide, TNF-alpha, MNCV, or nerve morphology in this experiment. These results indicate that gliclazide has a beneficial effect on peripheral neuropathy in STZ-induced diabetic rats, irrespective of blood glucose levels.