Inhibition of Grb2-mediated activation of MAPK signal transduction suppresses NOR1/CB1954-induced cytotoxicity in the HepG2 cell line

LncRNA PVT1 knockdown alleviated ox-LDL-induced vascular endothelial cell injury and atherosclerosis by miR-153-3p/GRB2 axis via ERK/p38 pathway

BACKGROUND AND AIMS

LncRNA plasmacytoma variant translocation 1 (PVT1) plays a regulatory role in some cardiovascular diseases, but its role in atherosclerosis (AS) remains barely explored. The study aimed to investigate the effects of PVT1 on high fat diet-induced AS and its potential mechanisms.

METHODS AND RESULTS

ApoE -/- mice were fed with high fat diet for 8 weeks to establish an AS model. Lentiviral vectors containing PVT1 short hairpin RNA (PVT1-shRNA) or NC-shRNA were administered by tail vein injection. Cell viability, apoptosis, inflammatory factor secretion, and cellular oxidative stress were measured to evaluate oxidized low-density lipoprotein (ox-LDL)-induced human umbilical vein endothelial cell (HUVEC) injury. Dual-luciferase reporter gene and RNA immunoprecipitation assays were used to confirm the interaction between miR-153-3p and PVT1 or growth factor receptor binding protein 2 (GRB2). Atherosclerotic lesions, lipid deposition, and cell apoptosis in aorta were analyzed by H&E, Oil Red O, and TUNEL straining. PVT1 knockdown alleviated ox-LDL-induced inflammation, apoptosis and oxidative stress in HUVECs. PVT1 acted as a sponge of miR-153-3p, and GRB2 was confirmed as a target of miR-153-3p. MiR-153-3p overexpression attenuated the enhanced effects of PVT1 on ox-LDL-induced cell damage. GRB2 overexpression reversed the mitigating effects of miR-153-3p on ox-LDL-caused injury. Inhibiting PVT1 restrained the activation of ERK1/2 and p38 pathway via miR-153-3p/GRB2 axis. Additionally, silencing PVT1 in vivo reduced atherosclerotic plaques, lipid deposition, inflammation, oxidative stress, and apoptosis in AS mice.

CONCLUSION

PVT1 knockdown alleviated ox-LDL-induced vascular endothelial cell injury and atherosclerosis through miR-153-3p/GRB2 axis via ERK1/2 and p38 pathway.

Grb2 Induces Cardiorenal Syndrome Type 3: Roles of IL-6, Cardiomyocyte Bioenergetics, and Akt/mTOR Pathway

Cardiorenal syndrome type 3 (CRS-3) is damage to the heart following acute kidney injury (AKI). Although many experiments have found that inflammation, oxidative stress, and cardiomyocyte death are involved in cardiomyocyte pathophysiological alterations during CRS-3, they lack a non-bias analysis to figure out the primary mediator of cardiac dysfunction. Herein proteomic analysis was operated in CRS-3 and growth factor receptor-bound protein 2 (Grb2) was identified as a regulator involving AKI-related myocardial damage. Increased Grb2 was associated with cardiac diastolic dysfunction and mitochondrial bioenergetics impairment; these pathological changes could be reversed through the administration of a Grb2-specific inhibitor during AKI. Molecular investigation illustrated that augmented Grb2 promoted cardiomyocyte mitochondrial metabolism disorder through inhibiting the Akt/mTOR signaling pathway. Besides that, Mouse Inflammation Array Q1 further identified IL-6 as the upstream stimulator of Grb2 upregulation after AKI. Exogenous administration of IL-6 induced cardiomyocyte damage and mitochondrial bioenergetics impairment, whereas these effects were nullified in cardiomyocytes pretreated with Grb2 inhibitor. Our results altogether identify CRS-3 to be caused by the upregulations of IL-6/Grb2 which contribute to cardiac dysfunction through inhibiting the Akt/mTOR signaling pathway and inducing cardiomyocyte mitochondrial bioenergetics impairment. This finding provides a potential target for the clinical treatment of patients with CRS-3.

CircRNA_101505 sensitizes hepatocellular carcinoma cells to cisplatin by sponging miR-103 and promotes oxidored-nitro domain-containing protein 1 expression

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors and a leading cause of cancer-related deaths worldwide. Emerging studies have shown that circular RNAs (circRNAs) are differentially expressed in HCC and play an important role in HCC pathogenesis and metastasis. However, the mechanism of circRNA in the chemoresistance of HCC remains unclear. In this study, we aimed to investigate the role of circRNA in cisplatin resistance of HCC. We identified a novel circRNA circRNA_101505 that was decreased in cisplatin-resistant HCC tissues and cell lines, and associated with a poor survival outcome. Gain-of-function investigations showed that overexpression of circRNA_101505 suppressed cancer cell growth in vivo and in vitro, and enhanced cisplatin toxicity in HCC cells. Mechanistic studies found that circRNA_101505 could sensitize HCC cells to cisplatin by sponging miR-103, and thereby promoting oxidored-nitro domain-containing protein 1 (NOR1) expression. In conclusion, the significant inhibitory effects indicate circRNA_101505 to be a potential therapeutic target for HCC treatment. Our findings provide significant evidence to further elucidate the therapeutic use of circRNA in HCC.

Synergistic anticancer effect of Grb2 and ITGA1 on cancer cells highly expressing Grb2 through suppressing ERK phosphorylation

BACKGROUND

Growth factor receptor bound protein 2 (Grb2) is known to be an adaptor protein that provides a critical link between cell surface growth factor receptors and the MAPK signaling. It was shown that high expression of Grb2 enhances cancer cells proliferation, invasion and malignant transformation.

OBJECTIVE

In this study, we aimed to systemically understand the function of Grb2 in cancer.

METHODS

The expression of Grb2 in different cancer cell lines was examined from a publicly available database and we chose two cancer cell lines highly expressing Grb2 to investigate the role of Grb2. To systemically understand the function of Grb2 in cancer cells, proteomic profiles also were analyzed.

RESULT

The results suggested that downregulation of Grb2 reduced cell proliferation in Hela cells and Jurkat cells. In addition, knockdown of Grb2 reduced the expression of ITGA1 and inhibited the phosphorylation of ERK. Intriguingly, simultaneous inhibition of Grb2 and ITGA1 resulted in a greater inhibition of phosphorylated ERK than either inhibition of Grb2 or ITGA1, and thus triggered marked apoptosis in Hela cells and Jurkat cells. These results suggest a synergistic anticancer effect of Grb2 and ITGA1 mediated by the ERK pathway in cancer cells highly expressing Grb2. In conclusion, we provided evidence that inhibition of Grb2 and ITGA1 might be an attractive target for therapeutic intervention against the cancer growth of cancers with high Grb2 expression.

T-cell immunoglobulin mucin-3 as a potential inducer of the epithelial-mesenchymal transition in hepatocellular carcinoma

T-cell immunoglobulin mucin (TIM)-3 is an important member of the TIM gene family, which was thought to contribute to the progression of numerous types of cancer, including hepatocellular carcinoma (HCC); however, the mechanism underlying TIM-3 functions in HCC progression has not yet been extensively investigated. The present study aimed to investigate the function of TIM-3 in the metastasis of HCC and to determine whether the alteration of TIM-3 expression levels regulated the epithelial-mesenchymal transition (EMT) occurrence of HCC, using epithelial (E)-cadherin, neuronal (N)-cadherin, matrix metallopeptidase-9 (MMP-9), Twist 1, Slug, Snail, and Smad as EMT biomarkers. The results demonstrated that upregulation of TIM-3 using TIM-3 lentiviral activation particles (5 µl) increased cell migration and invasion, which was decreased in TIM-3 short interfering RNA-infected cells (10 µM, 3 µl) correspondingly. SMMC-7721 HCC cells were used as the control. EMT was aggravated in TIM-3 upregulated SMMC-7721 cells, which was attenuated in the TIM-3 interference group, accompanied by an alteration of E-cadherin, N-cadherin, MMP-9, Twist 1, Slug, Snail and Smad expression levels. The data presented suggests that TIM-3 serves an essential role in the metastasis of HCC, the mechanism of which was associated with EMT occurrence. Interference of TIM-3 is expected to be an effective means to prevent and control EMT, and further the metastasis of HCC.

Oxidored-nitro domain-containing protein 1 promotes liver fibrosis by activating the Wnt/β-catenin signaling pathway in vitro

Hepatic fibrosis is a characteristic of various types of chronic liver diseases, and may further develop into liver cirrhosis and liver cancer. Oxidored‑nitro domain‑containing protein 1 (NOR1) expression levels are greater in hepatitis, cirrhosis and hepatocellular carcinoma samples compared with from normal liver samples. However, the importance of NOR1 in liver fibrosis remains to be elucidated. The present study aimed to investigate the effect of NOR1 on the proliferation and matrix expression of human hepatic stellate cells (HSCs) in vitro. Additionally, the molecular mechanisms underlying the role of NOR1 in the activation of HSCs was investigated. The present study determined that transforming growth factor β1 (TGF‑β1) may induce NOR1 expression in HSCs in a dose‑dependent manner, as determined by reverse transcription‑quantitative polymerase chain reaction and western blot analysis. NOR1‑small hairpin (sh)RNA was transfected into TGF‑β1‑treated HSCs to knock down NOR1. The MTT assay revealed that TGF‑β1‑induced cell proliferation was significantly inhibited in the NOR1‑shRNA group. In addition, NOR1 knockdown significantly inhibited TGF‑β1‑induced protein expression of fibrosis indexes, including collagen 1, 3 and α‑smooth muscle actin (α‑SMA). Subsequently, NOR1‑pcDNA3.1 was transfected into HSCs to overexpress NOR1. It was revealed that NOR1 overexpression may activate the Wnt/β‑catenin pathway in HSCs. The gain‑of function experiments demonstrated that NOR1 overexpression promoted cell proliferation and the expression of fibrosis indexes; however, these effects may be attenuated by dickkopf‑1, an inhibitor of the Wnt/β‑catenin signaling pathway. In conclusion, the present study demonstrated that NOR1 activates HSCs and contributes to liver fibrosis in vitro and this effect was achieved through the activation of the Wnt/β‑catenin pathway. Therefore, the current study may provide a novel target for the treatment of chronic liver diseases.

Oxidored-nitro domain-containing protein 1 expression is associated with the progression of hepatocellular carcinoma

Hepatocarcinogenesis is a stepwise process during which multiple genes are altered. Understanding the molecular mechanisms that induce hepatocarcinogenesis may improve the screening, prevention and treatment of patients with hepatocellular carcinoma (HCC). In recent years, the oxidored-nitro domain-containing protein 1 (NOR1) gene has been identified to have an important role in the development of HCC in vitro experiments. The current study aimed to examine the expression of NOR1 mRNA and protein expression in specimens of normal liver, hepatitis, cirrhosis and HCC, together representing the process of HCC development. Furthermore, the association between NOR1 expression and clinicopathological parameters of HCC patients was analyzed. Tissue microarrays containing the specimens of human normal liver, hepatitis, cirrhosis and HCC were purchased, and in situ hybridization and immunohistochemistry were used to detect the expression of NOR1 mRNA and protein expression, respectively. It was revealed that the positive rate of NOR1 protein and mRNA expression in the specimens of hepatitis and cirrhosis were not significantly different from that in the normal liver samples. However, the specimens of HCC exhibited an increased positive rate of NOR1 protein and mRNA expression in comparison with the normal liver samples. In addition, a higher positive rate of NOR1 protein expression was observed in HCC patients with a poor pathological differentiation grade and high tumor node metastasis (TNM) stage. In conclusion, the present study provides evidence, for the first time, of the increased expression of NOR1 in human HCC tissues, and its correlation with the pathological stage and TNM status. These findings indicate that NOR1 may be involved in the progression of HCC and it could be employed as a predictive biomarker in HCC development.