Yong Shu

Inhibition of fatty acid synthase supresses osteosarcoma cell invasion and migration.

BACKGROUND Fatty acid synthase (FASN) is overexpressed in a variety of human cancers, and may be involved in cancer metastasis. Hence, the strategies targeted on FASN may have therapeutic potential for treating cancer metastasis. OBJECTIVES The aim of this study is to investigate the correlation of FASN expression with metastasis in human osteosarcoma. MATERIALS AND METHODS Human osteosarcoma cell lines U2-OS and osteosarcoma biopsy specimens were employed in this study. The expression of FASN protein in osteosarcoma specimens was detected by IHC (immunohistochemistry) and the relationship with metastasis was analyzed. We performed the cerulenin, an inhibitor of FASN, to inhibit FASN expression in U2-OS cells. Western blot and RT-PCR were performed to investigate the expression of FASN in U2-OS cells. Cells mobility was detected by wound healing and Transwell assays. RESULTS Results showed that the FASN expression level in the cases with pulmonary metastases was significantly higher than in those without metastasis. In vitro, the invasion and migration of U2-OS cells were suppressed by inhibiting FASN. Our findings suggested that FASN may be involved in osteosarcoma metastasis.

Let-7a suppresses macrophage infiltrations and malignant phenotype of Ewing sarcoma via STAT3/NF-κB positive regulatory circuit

The interaction between tumors cells, tumor-derived humoral factors and the bone marrow in the bone niches has been shown to be essential for bone tumor initiation and promotion. Among the tumor stromal cells, tumor-associated macrophages (TAMs) are usually the most abundant immune population. Previously, we reported that let-7a functions as a tumor suppressor in ES. Herein, we found that the suppressive effects are not only limited on the malignant phenotype of tumor cells but also on the regulation of macrophage infiltration. We observed that the let-7a expression is negatively related to macrophage infiltrations in ES. Moreover, overexpression of putative ts-miRNA let-7a significantly suppressed the recruitment of PBMCs in vitro and decreased the macrophage infiltrations in ES-xenografted tumors in vivo. Most importantly, a positive regulatory feedback loop consisting of let-7a, signal transducer and activator of transcription 3 (STAT3), and nuclear factor-kappa B (NF-κB) (let-7a/STAT3/NF-κB) was involved in let-7a-mediated suppressive effects. These data might provide evidence of a novel intracellular signaling network function in ES pathogenesis, and manipulating this novel feedback loop will have therapeutic potential for ES patients.

Inhibition of Aurora-B suppresses osteosarcoma cell migration and invasion.

Previous studies have suggested that Aurora-B may be involved in cancer metastasis. However, its role has been poorly evaluated in osteosarcoma (OS). The aim of this study was to investigate the correlation between Aurora-B expression and metastasis in human OS. The human OS cell line, U2-OS, and OS biopsy specimens were used in the study. The expression of Aurora-B protein was examined using immunohistochemistry and western blotting in OS tissues and U2-OS cells, respectively. AZD1152-hydroxyquinazoline-pyrazol-anilide, an inhibitor of Aurora-B, was used to inhibit Aurora-B expression in U2-OS cells. The effect of Aurora-B inhibition on U2-OS cell proliferation, invasion and migration was assessed using MTT, colony formation, wound healing and Transwell assays. The results showed that positive expression of the Aurora-B protein was observed in the nucleus, and that Aurora-B expression levels in the cases with pulmonary metastases were significantly higher than in those without metastasis. In vitro, the proliferation, invasion and migration of U2-OS cells were suppressed by the inhibition of Aurora-B. These results suggest that Aurora-B may be involved in OS metastasis, and may be a promising target in the treatment of OS metastasis.

Posterior lumbar interbody fusion using spinous process and laminae

Posterior lumbar interbody fusion (PLIF) is indicated for many patients with pain and/or instability of the lumbar spine. We performed 36 PLIF procedures using the patients lumbar spinous process and laminae, which were inserted as a bone graft between two vertebral bodies without using a cage. The mean lumbar lordosis and mean disc height to vertebral body ratio were restored and preserved after surgery. There were no serious complications. These results suggest that this procedure is safe and effective.

LIM Mineralization Protein-1 Inhibits the Malignant Phenotypes of Human Osteosarcoma Cells

Osteosarcoma (OS), also known as osteogenic sarcoma, is the most common primary malignancy of bone tumor in children and adolescents. However, its underlying molecular pathogenesis is still only vaguely understood. Recently, LIM mineralization protein-1 (LMP-1) was reported to be an essential positive regulator of osteoblast differentiation. In the present study, we found that the expression of LMP-1 is downregulated in OS tissues compared with adjacent normal tissues. Moreover, we restored the expression of LMP-1 through a recombinant adenovirus. Overexpression of LMP-1 inhibited cell proliferation and invasion, arrested cell cycle progression, and induced apoptosis in vitro. Finally, ectopic LMP-1 expression suppressed the expression of Runx2 and BMP-2 in OS cells. These data demonstrate that LMP-1 is an essential tumor suppressor in the OS pathological process, which will provide a new opportunity for discovering and identifying novel effective treatment strategies.

Enhanced antitumor activity of epirubicin combined with cerulenin in osteosarcoma

Osteosarcoma (OS) is the most common primary malignant neoplasm in children and adolescents. Epirubicin is one of the chemotherapeutic agents currently used for the treatment of OS; however, the efficacy of chemotherapy is hampered by the acquired drug resistance of OS. Cerulenin, an inhibitor of fatty acid synthase, has been defined as a candidate tumor suppressor. In this study, we explored the combined effect of cerulenin plus the chemotherapy drug, epirubicin, on human OS U2-OS cells in vitro and in vivo. We demonstrated that cerulenin plus epirubicin induced synergistic growth inhibition and enhanced apoptosis in U2-OS cells. We also demonstrated that cerulenin plus epirubicin synergistically suppressed tumor growth in subcutaneously xenografted U2-OS cells in athymic nude mice. Our results indicate that cerulenin enhances the anti-OS effects of epirubicin in vivo and in vitro.

Transcription factor NF‑YA promotes a malignant phenotype by upregulating fatty acid synthase expression

Recent studies have revealed that increased expression of the alpha subunit of nuclear transcription factor Y (NF-YA) is associated with the malignant phenotype of various tumors. However, whether elevated expression of NF-YA promotes a malignant phenotype in osteosarcoma (OS), and the molecular mechanisms underlying this predicted effect is currently unknown. In the present study, small hairpin RNA (shRNA)-mediated knockdown of endogenous NF-YA significantly inhibited the migration and invasion capabilities of OS cells in vitro, whereas ectopic expression of NF-YA increased the migration and invasion capabilities of these cells. In addition, the induction of upregulated NF-YA expression on the malignant phenotype of OS cells was attenuated by silencing fatty acid synthase (FASN) expression. Furthermore, the expression level of FASN was increased by upregulating NF-YA, while decreased FASN expression was observed following NF-YA silencing in OS cells. The results of the present study suggest that NF-YA may promote a malignant phenotype in OS cells, in part, by activating the FASN signaling pathway, which may represent a promising target for the management of OS.

Transepithelial transport of Cerulenin across Caco-2 cell monolayers

SummaryThe transepithelial transport of Cerulenin across Caco-2 cell monolayers was examined in this study. The permeated amounts of Cerulenin were measured by HPLC method to calculate the permeation rate and the apparent permeability coefficient (Papp). The transport of Cerulenin was independent on apical pH and exhibited concentration-dependent and nonsatuable even at 10 mM Cerulenin. The permeation rate at 1 mM Cerulenin in the apical-to-basolateral direction was 0.151 ng/min/mg of protein and the Papp was 3.76×10−6 cm/second. The permeation rate of Cerulenin was affected by neither metabolic inhibitors nor inhibitors for P-glycoprotein, as was the same case in monolayers treated with cytochalasin D. All these data from experiments indicated that transport of Cerulenin across Caco-2 cell monolayers was not mediated by ATP-dependent transport systems nor via paracellular pathway, but via passive diffusion without efflux by P-glycoprotein.