Oncology reports
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Leucine-rich repeat containing G protein-coupled receptor 5 (LGR5), one of the target genes of the Wnt signaling pathway, has recently been identified as a marker for brain cancer stem-like cells. However, the role of LGR5 in glioma is poorly understood. The aim of the present study was to investigate the relationship between LGR5 expression and pathological grade in glioma, and the impact of LGR5 on the proliferation of glioma cells in vitro and in vivo. ⋯ The results revealed that i) LGR5 was positively expressed in all glioma specimens and its expression increased with pathologic grade and Ki-67 expression; ii) LGR5 was highly expressed in three glioma cell lines and its expression was reduced significantly by siRNA; and iii) RNAi-mediated downregulation of endogenous LGR5 in U87 cells resulted in the suppression of cell proliferation, arrest of the cell cycle, and reduction in clone and tumorsphere formation in vitro. In addition, LGR5 depletion significantly inhibited tumor orthotopic xenograft growth in nude mice. These findings indicate that LGR5 plays a major role in gliomagenesis by promoting neoplastic cell proliferation, suggesting LGR5 as a molecular marker for pathology and a novel therapeutic target for malignant glioma.
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Hepatocellular carcinoma is the most common type of liver cancer. The risk of hepatocellular carcinoma for type 2 diabetic patients is greater than that for non-diabetic individuals although the mechanism is unclear. The cancer suppressor resveratrol inhibits cancer cell proliferation partly through the STAT3 signaling pathway. ⋯ This effect was suppressed by resveratrol (100 µM), and the effect on the p-STAT3 signaling pathway was found to be SIRT1-dependent. Our findings may provide new insights into the mechanism by which resveratrol suppresses HepG2 cell proliferation under conditions of high glucose. Furthermore, this information may provide the basis for a novel therapeutic strategy for hepatocellular carcinoma patients suffering from either diabetes or hyperglycemia.
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Telomerase is a reverse transcriptase ribonucleo-protein (h-TERT) that synthesizes telomeric repeats using its RNA component (h-TERC) as a template. Telomerase dysfunction has been associated with both fibrogenesis and carcinogenesis. In this study, we aimed to evaluate the telomerase mRNA expression levels of both subunits (h-TERT and h-TERC) in lung tissue and bronchoalveolar lavage fluid (BALF) from patients with idiopathic pulmonary fibrosis (IPF) and non-small cell lung cancer (NSCLC), since there are indications of common pathogenetic pathways in these diseases. ⋯ More specifically, h-TERT mRNA levels in the patients with IPF were higher compared with those in the controls (p=0.03) and patients with NSCLC (p=0.007). The attenuation of telomerase gene expression in IPF in comparison to lung cancer suggests a differential role of this regulatory gene in fibrogenesis and carcinogenesis. Further functional studies are required in order to further elucidate the role of telomerase in these devastating diseases.
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The recent discovery of fusion oncokinases in a subset of non-small cell lung carcinomas (NSCLCs) is of considerable clinical interest, since NSCLCs that express such fusion oncokinases are reportedly sensitive to kinase inhibitors. To better understand the role of recently identified ROS1 and RET fusion oncokinases in pulmonary carcinogenesis, we examined 114 NSCLCs for SLC34A2-ROS1, EZR-ROS1, CD74-ROS1 and KIF5B-RET fusion transcripts using RT-polymerase chain reaction and subsequent sequencing analyses. Although the expression of SLC34A2-ROS1, EZR-ROS1, or KIF5B-RET fusion transcripts was not detected in any of the cases, the expression of CD74-ROS1 fusion transcripts was detected in one (0.9%) of the 114 NSCLCs. ⋯ ROS1 protein overexpression was immunohistochemically detected in a cancer-specific manner in both the primary cancer and the lymph node metastatic cancer. No somatic mutations were detected in the mutation cluster regions of the KRAS, EGFR, BRAF and PIK3CA genes and the entire coding region of p53 in the carcinoma, and the expression of ALK fusion was negative. The above results suggest that CD74-ROS1 fusion is involved in the carcinogenesis of a subset of NSCLCs and may contribute to the elucidation of the characteristics of ROS1 fusion-positive NSCLC in the future.
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Porphyromonas gingivalis lipopolysaccharide (P. gingivalis LPS) promotes macrophage-derived foam cell formation, however, the mechanisms are not well established. In macrophages, lipid uptake is mediated by scavenger receptors including SR-A and CD36, while the cholesterol efflux is mediated by ATP-binding cassette transporter G1 (ABCG1), ABCA1 and SR-BI. We further investigated the mechanisms underlying the dysregulation by P. gingivalis LPS of these regulators resulting in the promotion of lipid accumulation in THP-1-derived macrophages. ⋯ Moreover, small hairpin RNA (shRNA) targeting heme oxygenase-1 (HO-1) augmented the P. gingivalis LPS-induced atherogenic effects on the expression of c-Jun/AP-1, CD36, ABCA1 and calpain activity. Accordingly, P. gingivalis LPS-regulated promotion of lipid accumulation in foam cells was also exacerbated by HO-1 shRNA. These results indicate that P. gingivalis LPS confers a exacerbation effect on the formation of foam cells by a novel HO-1-dependent mediation of cholesterol efflux and lipid accumulation in macrophages.