Nordentatin Inhibits Neuroblastoma Cell Proliferation and Migration through Regulation of GSK-3 Pathway

Cancer is caused by abnormal cell changes leading to uncontrolled cell growth. The specific characteristics of cancer cells, including the loss of apoptotic control and the ability to migrate into and invade the surrounding tissue, result in cancer cell metastasis to other parts of the body. Therefore, the inhibition of the proliferation, migration, and invasion of cancer cells are the principal goals in the treatment of cancer. This study aimed to investigate the inhibitory activity of nordentatin, a coumarin derivative isolated from Clausena harmandiana, regarding the proliferation and migration of human neuroblastoma cells (SH-SY5Y). Nordentatin at a concentration of 100 µM showed cell cytotoxicity toward SH-SY5Y that was significantly different from that of the control group (p < 0.01) at 24, 48, and 72 h. Moreover, nordentatin inhibited SH-SY5Y proliferation by inhibiting the antiapoptotic protein Mcl-1, leading to the cleavage of caspase-3 and resulting in the inhibition of a migratory protein, MMP-9, through the GSK-3 pathway (compared with cells treated with a GSK inhibitor). These results suggest that nordentatin inhibited the proliferation and migration of neuroblastoma cells through the GSK-3 pathway.     

Inhibition of lysine-specific demethylase 1 by the acyclic diterpenoid geranylgeranoic acid and its derivatives

Lysine-specific demethylase 1 (LSD1) is upregulated in many cancers, especially neuroblastoma. We set out to explore whether geranylgeranoic acid (GGA) inhibits LSD1 activity by using recombinant human LSD1. GGA inhibited LSD1 activity with IC₅₀ similar to that of the clinically used drug tranylcypromine. In human neuroblastoma SH-SY5Y cells, GGA induced NTRK2 gene expression alongside upregulation of histone H3 with dimethylated lysine-4 in the regulatory regions of the NTRK2 gene. Dihydrogenation of GGA reinforced the LSD1-inhibitory effect in a position-dependent manner. The inhibitory effects of dihydro-derivatives of GGA on recombinant LSD1 strongly correlated with the induction of NTRK2 gene expression in SH-SY5Y cells. These data demonstrate for the first time the efficient LSD1-inhibitor activity of GGA and its derivatives, providing a novel prospect of preventing cancer onset by using GGA to regulate epigenetic modification.     

Oral Metronomic Topotecan Sensitizes Crizotinib Antitumor Activity in ALKF1174L Drug-Resistant Neuroblastoma Preclinical Models

BACKGROUND: Anaplastic lymphoma kinase (ALK) inhibitor crizotinib has proven to be effective in the treatment of ALK-mutated neuroblastoma, but crizotinib resistance was commonly observed in patients. We aimed to overcome crizotinib resistance by combining with the MEK inhibitor trametinib or low-dose metronomic (LDM) topotecan in preclinical neuroblastoma models. METHODS: We selected a panel of neuroblastoma cell lines carrying various ALK genetic aberrations to assess the therapeutic efficacy on cell proliferation in vitro. Downstream signals of ALK activation, including phosphorylation of ERK1/2, Akt as well as HIF-1α expression were evaluated under normoxic and hypoxic conditions. Tumor growth inhibition was further assessed in NOD/SCID xenograft mouse models. RESULTS: All NBL cell lines responded to crizotinib treatment but at variable ED50 levels, ranging from 0.25 to 5.58 μM. ALK-mutated cell lines SH-SY5Y, KELLY, LAN-5, and CHLA-20 are more sensitive than ALK wild-type cell lines. In addition, we demonstrated that under hypoxic conditions, all NBL cell lines showed marked decrease of ED50s when compared to normoxia except for KELLY cells. Taking into consideration the hypoxia sensitivity to crizotinib, combined treatment with crizotinib and LDM topotecan demonstrated a synergistic effect in ALK^F1174L-mutated SH-SY5Y cells. In vivo, single-agent crizotinib showed limited antitumor activity in ALK^F1174L-mutated SH-SY5Y and KELLY xenograft models; however, when combined with topotecan, significantly delayed tumor development was achieved in both SH-SY5Y and KELLY tumor models. CONCLUSIONS: Oral metronomic topotecan reversed crizotinib drug resistance in the ALK^F1174L-mutated neuroblastoma preclinical model.     

Olfactory Ensheathing Cell-Conditioned Medium Reverts Aβ<Subscript>25–35</Subscript>-Induced Oxidative Damage in SH-SY5Y Cells by Modulating the Mitochondria-Mediated Apoptotic Pathway

Olfactory ensheathing cells (OECs) are a type of glia from the mammalian olfactory system, with neuroprotective and regenerative properties. β-Amyloid peptides are a major component of the senile plaques characteristic of the Alzheimer brain. The amyloid beta (Aβ) precursor protein is cleaved to amyloid peptides, and Aβ_25–35 is regarded to be the functional domain of Aβ, responsible for its neurotoxic properties. It has been reported that Aβ_25–35 triggers reactive oxygen species (ROS)-mediated oxidative damage, altering the structure and function of mitochondria, leading to the activation of the mitochondrial intrinsic apoptotic pathway. Our goal is to investigate the effects of OECs on the toxicity of aggregated Aβ_25–35, in human neuroblastoma SH-SY5Y cells. For such purpose, SH-SY5Y cells were incubated with Aβ_25–35 and OEC-conditioned medium (OECCM). OECCM promoted the cell viability and reduced the apoptosis, and decreased the intracellular ROS and the lipid peroxidation. In the presence of OECCM, mRNA and protein levels of antioxidant enzymes (SOD1 and SOD2) were upregulated. Concomitantly, OECCM decreased mRNA and the protein expression levels of cytochrome c, caspase-9, caspase-3, and Bax in SH-SY5Y cells, and increased mRNA and the protein expression level of Bcl-2. However, OECCM did not alter intracellular Ca²⁺ concentration in SH-SY5Y cells. Taken together, our data suggest that OECCM ameliorates Aβ_25–35-induced oxidative damage in neuroblastoma SH-SY5Y cells by inhibiting the mitochondrial intrinsic pathway. These data provide new insights into the functional actions of OECCM on oxidative stress-induced cell damage.     

Morphological Differentiation Towards Neuronal Phenotype of SH-SY5Y Neuroblastoma Cells by Estradiol,Retinoic Acid and Cholesterol

Human SH-SY5Y neuroblastoma cells maintain their potential for differentiation and regression in culture conditions. The induction of differentiation could serve as a strategy to inhibit cell proliferation and tumor growth. Previous studies have shown that differentiation of SH-SY5Y cells can be induced by all-trans-retinoic-acid (RA) and cholesterol (CHOL). However, signaling pathways that lead to terminal differentiation of SH-SY5Y cells are still largely unknown. The goal of this study was to examine in the RA and CHOL treated SH-SY5Y cells the additive impacts of estradiol (E₂) and brain-derived neurotrophic factor (BDNF) on cell morphology, cell population growth, synaptic vesicle recycling and presence of neurofilaments. The above features indicate a higher level of neuronal differentiation. Our data show that treatment for 10 days in vitro (DIV) with RA alone or when combined with E₂ (RE) or CHOL (RC), but not when combined with BDNF (RB), significantly (p < 0.01) inhibited the cell population growth. Synaptic vesicle recycling, induced by high-K⁺ depolarization, was significantly increased in all treatments where RA was included (RE, RC, RB, RCB), and when all agents were added together (RCBE). Specifically, our results show for the first time that E₂ treatment can alone increase synaptic vesicle recycling in SH-SY5Y cells. This work contributes to the understanding of the ways to improve suppression of neuroblastoma cells’ population growth by inducing maturation and differentiation.     

Differentiation Induces Dramatic Changes in miRNA Profile,Where Loss of Dicer Diverts Differentiating SH-SY5Y Cells Toward Senescence

MicroRNAs (miRNAs) are generated by endonuclease activity of Dicer, which also helps in loading of miRNAs to their target sequences. SH-SY5Y, a human neuroblastoma and a cellular model of neurodevelopment, consistently expresses genes related to neurodegenerative disorders at different biological levels (DNA, RNA, and proteins). Using SH-SY5Y cells, we have studied the role of Dicer and miRNAs in neuronal differentiation and explored involvement of P53, a master regulator of gene expression in differentiation-induced induction of miRNAs. Knocking down Dicer gene induced senescence in differentiating SH-SY5Y cells, which indicate the essential role of Dicer in brain development. Differentiation of SH-SY5Y cells by retinoic acid (RA) or RA + brain-derived neurotrophic factor (BDNF) induced dramatic changes in global miRNA expression. Fully differentiated SH-SY5Y cells (5-day RA followed by 3-day BDNF) significantly (p < 0.05 and atleast >3-fold change) upregulated and downregulated the expression of 77 and 17 miRNAs, respectively. Maximum increase was observed in the expression of miR-193-5p, miR-199a-5p, miR-192, miR-145, miR-28-5p, miR-29b, and miR-222 after RA exposure and miR-193-5p, miR-146a, miR-21, miR-199a-5p, miR-153, miR-29b, and miR-222 after RA + BDNF exposure in SH-SY5Y cells. Exploring the role of P53 in differentiating SH-SY5Y cells, we have observed that induction of miR-222, miR-192, and miR-145 is P53 dependent and expression of miR-193a-5p, miR-199a-5p, miR-146a, miR-21, miR-153, and miR-29b is P53 independent. In conclusion, decreased Dicer level enforces differentiating cells to senescence, and differentiating SH-SY5Y cells needs increased expression of P53 to cope up with changes in protein levels of mature neurons.     

Growth factor ligands of tyrosine kinase receptors activate the Rous sarcoma virus promoter by a Ras- and Raf-dependent mechanism

In PC12 cells, NGF and other ligands of tyrosine kinase receptors increased the activity of the Rous sarcoma virus (RSV) promoter. IGF-1 stimulated the RSV promoter in SH-SY5Y neuroblastoma cells. This promoter was also activated by oncogenic Ras and Raf in different cell types, and growth factor induction was inhibited by expression of dominant negative forms of ras and raf, showing that its effect is mediated by a Ras- and Raf-dependent mechanism. Therefore, the RSV promoter should not be used in the determination of transfection efficiency in the studies on regulation of gene expression by ligands of tyrosine kinase receptors, ras and raf.     

TET2在帕金森病细胞模型中的表达及机制研究

目的:迄今为止,帕金森病(PD)发生的分子机制尚未完全阐明,本研究旨在体外细胞模型中寻找PD新型表观遗传标志物,探索其发病机制。方法:本次研究使用的细胞为神经母细胞瘤细胞系SH-SY5Y。首先,我们用CCK-8检测细胞活力,选取合适浓度的MPP+构建PD细胞损伤模型。再用PBS和MPP+分别处理SH-SY5Y细胞,用RT-qPCR检测了几个甲基化酶与去甲基化酶DNMT1,DNMT3A,DNMT3B及TET1, TET2, TET3的mRNA的表达水平,并用蛋白印迹检测TET2蛋白水平,免疫荧光检测了TET2蛋白定位。进一步用慢病毒转染SH-SY5Y细胞敲低TET2后,检测细胞增殖。结果:本研究发现,MPP+对SH-SY5Y细胞增殖的抑制具有时间与浓度依赖性,我们最终选择2.5 mM MPP+作为后续的细胞处理浓度。与对照组相比,MPP+处理细胞TET2的mRNA及蛋白水平表达均增加,且蛋白进入细胞核增加;同时发现,敲低TET2表达可以延缓MPP+对SH-SY5Y细胞增殖的抑制作用。结论:在当前的研究中,我们报道了TET2蛋白可能是PD新型的表观遗传学标志物,提示我们将来也许可以使用TET2抑制剂来治疗PD,因此本研究有可能为PD提供新的治疗方向和靶点。     

Neurotropic and neuroprotective activities of the earthworm peptide Lumbricusin

We recently isolated a polypeptide from the earthworm Lumbricus terrestris that is structurally similar to defensin, a well-known antibacterial peptide. An 11-mer antibacterial peptide (NH₂-RNRRWCIDQQA), designated Lumbricusin, was synthesized based on the amino acid sequence of the isolated polypeptide. Since we previously reported that CopA3, a dung beetle peptide, enhanced neuronal cell proliferation, we here examined whether Lumbricusin exerted neurotropic and/or neuroprotective effects. Lumbricusin treatment induced a time-dependent increase (∼51%) in the proliferation of human neuroblastoma SH-SY5Y cells. Lumbricusin also significantly inhibited the apoptosis and decreased viability induced by treatment with 6-hydroxy dopamine, a Parkinson’s disease-mimicking agent. Immunoblot analyses revealed that Lumbricusin treatment increased ubiquitination of p27^Kip1 protein, a negative regulator of cell-cycle progression, in SH-SY5Y cells, and markedly promoted its degradation. Notably, adenoviral-mediated over-expression of p27^Kip1 significantly blocked the antiapoptotic effect of Lumbricusin in 6-hydroxy dopamine-treated SH-SY5Y cells. These results suggest that promotion of p27^Kip1 degradation may be the main mechanism underlying the neuroprotective and neurotropic effects of Lumbricusin.     

Resveratrol and pinostilbene confer neuroprotection against aging-related deficits through an ERK1/2-dependent mechanism

Age-related declines in motor function may be due, in part, to an increase in oxidative stress in the aging brain leading to dopamine (DA) neuronal cell death. In this study, we examined the neuroprotective effects of natural antioxidants resveratrol and pinostilbene against age-related DAergic cell death and motor dysfunction using SH-SY5Y neuroblastoma cells and young, middle-aged, and old male C57BL/6 mice. Resveratrol and pinostilbene protected SH-SY5Y cells from a DA-induced decrease in cell viability. Dietary supplementation with resveratrol and pinostilbene inhibited the decline of motor function observed with age. While DA and its metabolites (DOPAC and HVA), dopamine transporter, and tyrosine hydroxylase levels remain unchanged during aging or treatment, resveratrol and pinostilbene increased ERK1/2 activation in vitro and in vivo in an age-dependent manner. Inhibition of ERK1/2 in SH-SY5Y cells decreased the protective effects of both compounds. These data suggest that resveratrol and pinostilbene alleviate age-related motor decline via the promotion of DA neuronal survival and activation of the ERK1/2 pathways.     

八氯腺苷诱导SH-SY5Y和SK-N-SH细胞G2/M期阻滞的分子机制不同

为探索八氯腺苷的抗肿瘤作用机制,以神经母细胞瘤SH-SY5Y和SK-N-SH细胞为对象,采用四唑盐比色实验（MTT法）证明,八氯腺苷具有明显的抑制肿瘤细胞增殖的作用,这种抑制作用呈剂量-时间依赖性.流式细胞分析显示,10 μmol/L八氯腺苷作用48 h后可导致靶细胞生长停滞于G ^₂/M期;SH-SY5Y细胞发生明显细胞凋亡,但SK-N-SH细胞却未见凋亡.Hoechst 33342染色显示,SK-N-SH细胞发生了核分裂异常.蛋白质免疫印迹分析证明,10 μmol/L 八氯腺苷处理SH SY5Y 48～72 h后,G^₂检验点调节蛋白ATM、Chk1、Cdc25C和Cdc2磷酸化形式明显上调,同时伴有caspase-3的激活,提示SH-SY5Y细胞发生了G^₂检验点通路和细胞凋亡途径的激活.与SH-SY5Y细胞不同,在SK-N-SH细胞中,八氯腺苷处理24～96 h时,磷酸化ATM、磷酸化Chk1/Chk2、磷酸化Cdc25C以及磷酸化Cdc2的水平呈现逐渐降低的趋势.结果提示,SK-N-SH细胞在八氯腺苷处理后发生了G^₂检验点失败.蛋白质免疫印迹分析还显示,八氯腺苷可诱导p53在SH-SY5Y细胞的表达,但却不能影响SK—N-SH细胞的p53组成性表达水平.p21在SK-N-SH的组成性表达随八氯腺苷处理时间延长而逐渐减少,但在处理前后的SH-SY5Y细胞均未检测到p21蛋白的表达.上述实验结果提示,八氯腺苷抑制两种细胞增殖的机制不同：在SH-SY5Y细胞,八氯腺苷可激活ATM-Chk-Cdc25C-Cdc2/cyclin途径和凋亡通路,使细胞发生G_²/M期阻滞和细胞凋亡;在SK-N-SH细胞,八氯腺苷诱导G^₂检验点失败,导致细胞阻滞在有丝分裂期,并发生有丝分裂异常.2种不同的细胞命运可能还与p53和p21表达不同有关.     

Growth Inhibition and Apoptosis of Neuroblastoma Cells Through ROS-Independent MEK/ERK Activation by Sulforaphane

Deregulation of apoptosis alters the balance of cell proliferation and cell death, resulting in a variety of diseases, including cancer. In recent studies, sulforaphane (SFN) has demonstrated potent anti-tumor and chemopreventive activities. A possible signal transduction pathway has also been elucidated for SFN-induced apoptosis in human neuroblastoma SH-SY5Y cells. The present study further investigates the anti-proliferation activities of SFN through induced apoptosis in SH-SY5Y cells. We found that treating SH-SY5Y cells with SFN resulted in the depletion of mitochondrial membrane potential (Δψ), which in turn increased caspase 9, caspase 3, and the up-regulation of phosphorylated MEK/ERK without generating reactive oxygen species. Results were confirmed by MTT assay, which demonstrated the cytotoxic activity of SFN against SH-SY5Y cells (IC₅₀ values of 20 μM).     

A possible role for CXCR4 and its ligand, the CXC chemokine stromal cell-derived factor-1, in the development of bone marrow metastases in neuroblastoma

The homing of hemopoietic stem cells to the bone marrow is mediated by specific interactions occurring between CXCR4, which is expressed on hemopoietic stem cells, and its ligand, stromal cell-derived factor-1 (SDF-1), a CXC chemokine secreted by bone marrow stromal cells. In the present study we evaluated the possibility that neuroblastoma cells use a mechanism similar to that used by hemopoietic stem cells to home to the bone marrow and adhere to bone marrow stromal cells. Our study suggests that CXCR4 expression may be a general characteristic of neuroblastoma cells. SH-SY5Y neuroblastoma cells express not only CXCR4, but also its ligand, SDF-1. CXCR4 expression on SH-SY5Y neuroblastoma cells is tightly regulated by tumor cell-derived SDF-1, as demonstrated by the ability of neutralizing Abs against human SDF-1alpha to up-regulate CXCR4 expression on the tumor cells. The reduction in CXCR4 expression following short term exposure to recombinant human SDF-1alpha can be recovered as a result of de novo receptor synthesis. Recombinant human SDF-1alpha induces the migration of CXCR4-expressing SH-SY5Y neuroblastoma cells in CXCR4- and heterotrimeric G protein-dependent manners. Furthermore, SH-SY5Y cells interact at multiple levels with bone marrow components, as evidenced by the fact that bone marrow-derived constituents promote SH-SY5Y cell migration, adhesion to bone marrow stromal cells, and proliferation. These results suggest that SH-SY5Y neuroblastoma cells are equipped with adequate machinery to support their homing to the bone marrow. Therefore, the ability of neuroblastoma tumors to preferentially form metastases in the bone marrow may be influenced by a set of complex CXCR4-SDF-1 interactions.