Long noncoding RNA SNHG1 promotes breast cancer progression by regulating the miR-641/RRS1 axis.

An increasing number of studies have indicated the crucial involvement of long non-coding RNAs (lncRNAs) in the onset and progression of malignancies. However, a complete understanding of the molecular mechanism underlying the effect of abnormally expressed lncRNAs on breast cancer (BC) remains elusive. This study aimed to elucidate the influence of the lncRNA small nucleolar RNA host gene 1 (SNHG1) on BC progression and its underlying mechanism. Our findings revealed a conspicuous up-regulation of SNHG1 in both BC tissues and cells. The downregulation of SNHG1 was observed to inhibit BC cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) processes, while simultaneously promoting apoptosis. Furthermore, dual-luciferase reporter gene and RNA pull-down assays established that SNHG1 targeted miR-641 expression, while miR-641 targeted RRS1. Rescue studies demonstrated that in vitro SNHG1 silencing could be reversed by the miR-641 inhibitor, as well as by RRS1 upregulation. Moreover, in vivo downregulation of SNHG1 was found to inhibit BC growth. Through the inhibition of the miR-641 level, SNHG1 elevated the level of the downstream target RRS1, thereby fostering BC growth, migration, and invasion while inhibiting apoptosis. These findings suggest that SNHG1 may represent a potential therapeutic target for BC treatment.

The role of DDX46 in breast cancer proliferation and invasiveness: A potential therapeutic target.

DDX46, a member of DEAD-box (DDX) proteins, is associated with various cancers, while its involvement in the pathogenesis of breast cancer hasn't been reported so far. The study demonstrated the overexpression of DDX46 in human breast cancer cells and tissue samples, and correlated with high histological grade and lymph node metastasis. Downregulation of DDX46 in the breast cancer cell lines inhibited their proliferation and invasiveness in vitro. Furthermore, the growth of MDA-MB-231 xenografts was suppressed in nude mice by DDX46 knockingdown. Taken together, our findings suggest that DDX46 is an oncogenic factor in human breast cancer, and a potential therapeutic target.

Advances in the Relationship Between Regulator of Ribosome Synthesis 1 (RRS1) and Diseases.

A regulator of ribosome synthesis 1 (RRS1) was discovered in yeast and is mainly localized in the nucleolus and endoplasmic reticulum. It regulates ribosomal protein, RNA biosynthesis, and protein secretion and is closely involved in cellular senescence, cell cycle regulation, transcription, translation, oncogenic transformation etc., Mutations in the RRS1 gene are associated with the occurrence and development of Huntington's disease and cancer, and overexpression of RRS1 promotes tumor growth and metastasis. In this review, the structure, function, and mechanisms of RRS1 in various diseases are discussed.

Dysfunction of chaperone-mediated autophagy in human diseases.

Chaperone-mediated autophagy (CMA), one of the degradation pathways of proteins, is highly selective to substrates that have KFERQ-like motif. In this process, the substrate proteins are first recognized by the chaperone protein, heat shock cognate protein 70 (Hsc70), then delivered to lysosomal membrane surface where the single-span lysosomal receptor, lysosome-associated membrane protein type 2A (LAMP2A) can bind to the substrate proteins to form a 700 kDa protein complex that allows them to translocate into the lysosome lumen to be degraded by the hydrolytic enzymes. This degradation pathway mediated by CMA plays an important role in regulating glucose and lipid metabolism, transcription, DNA reparation, cell cycle, cellular response to stress and consequently, regulating many aging-associated human diseases, such as neurodegeneration, cancer and metabolic disorders. In this review, we provide an overview of current research on the functional roles of CMA primarily from a perspective of understanding and treating human diseases and also discuss its potential applications for diseases.

Ultra-high temperature mechanical property test of C/C composites by a digital image correlation method based on an active laser illumination and background radiation suppressing method with multi-step filtering.

Carbon/carbon (C/C) composites have been widely used in aerospace engineering because of their high temperature resistance. However, the commonly used non-contact deformation measurement method based on digital image correlation (DIC) still has some problems of speckle preparation and background radiation in an ultra-high temperature environment above 2000°C. An ultra-high temperature mechanical property test method based on active laser illumination and a background radiation suppressing method with multi-step filtering is proposed. In the proposed method, a laser with good coherence is used as the active illumination source to generate laser speckles that will not fall off or discolor as temperature increases. Also, a multi-step filtering device is devised with the combination of a spatial filter, plano-convex lens, polarizing filter, and two different bandpass filters, which can successfully suppress the background radiation and retain the characteristics of laser speckle patterns at the same time. Tensile tests of C/C composite had been carried out at ultra-high temperatures of 2200°C, 2400°C, 2600°C, and 2800°C. The experimental results showed that high-quality laser speckle images were obtained and the deviations between the elastic moduli obtained by the proposed method and by the high temperature contact extensometer were all less than 7%.

Phytic acid attenuates upregulation of GSK-3ß and disturbance of synaptic vesicle recycling in MPTP-induced Parkinson's disease models.

Heightened activity of glycogen synthase kinase-3ß (GSK-3ß) is linked to the degeneration of dopaminergic neurons in Parkinson's disease (PD). Phytic acid (PA), a naturally occurring compound with potent antioxidant property, has been shown to confer neuroprotection on dopaminergic neurons in PD. However, the underlying mechanism remains unclear. In the present study, MPTP and MPP+ treatments were used to model PD in mice and SH-SY5Y cells, respectively. We observed reduced tissue dopamine, disrupted synaptic vesicle recycling, and defective neurotransmitter exocytosis. Furthermore, expression of GSK-3ß was upregulated while that of ß-catenin was downregulated, concentration of cytosolic calcium was increased, and expressions of two dopamine carriers, dopamine transporter (DAT) and vesicular monoamine transporter 2 (VMAT2) were decreased. PA treatment attenuated the MPTP-induced upregulation of GSK-3ß, increase in cytosolic calcium concentration, decreases in the levels of DAT, VMAT2, tissue dopamine, and synaptic vesicle recycling. Importantly, disturbances in synaptic vesicle recycling are thought to be early events in PD pathology. These findings suggest that PA is a promising therapeutic agent to treat early events in PD.

Functional role of RRS1 in breast cancer cell proliferation.

RRS1 (human regulator of ribosome synthesis 1), an essential nuclear protein involved in ribosome biogenesis, is overexpressed in some human cancers, yet its role in breast cancer remains unclear. Here, we report a functional analysis of RRS1 in breast cancer and its likely mechanism. Immunohistochemistry (IHC) and RT-qPCR analyses indicated that RRS1 was commonly overexpressed in breast cancer tissues. The copy numbers of RRS1 were higher in tumours compared with those for normal tissues. And there was a significant correlation between copy number and mRNA expression. In addition, RRS1 overexpression was significantly correlated with lymph node metastasis and poor survival. RRS1 mRNA and protein levels were also significantly increased in a panel of human breast cancer cell lines. RRS1 knockdown inhibited proliferation and induced apoptosis and cell cycle arrest in all three cell lines. Furthermore, RRS1 knockdown suppressed the tumour formation and growth of MDA-MB-231 cells in nude mice. Additionally, RRS1 knockdown activated p53 and p21 in MCF-7 cells. A marked increase in the quantity of ribosome-free RPL11 was detected by Western blot. Moreover, co-immunoprecipitation (CoIP) experiments showed that RRS1 knockdown activated p53 by facilitating the direct contact of MDM2 and RPL11/RPL5. Taken together, our results suggest that RRS1 may contribute to breast cancer proliferation through RPL11/MDM2-mediated p53 activation. Therefore, RRS1 may be a promising target for breast cancer therapy.

Decreased expression of the CHD5 gene and its clinicopathological significance in breast cancer: Correlation with aberrant DNA methylation.

Chromodomain helicase DNA binding protein 5 (CHD5) has been identified as a tumor suppressor in mouse models. Downregulation of CHD5 gene expression is frequently observed in breast cancer cells and tissues. This may be explained by deletions or other mutations; however, alternative mechanisms require investigation. Therefore, the present study evaluated whether CHD5 aberrant methylation has a role in primary breast tumors. A total of 389 patients with primary breast cancer (including 252 paraffin-embedded specimens and 137 fresh-frozen samples) were enrolled in the present study. In the current study, reverse transcription-polymerase chain reaction (RT-PCR) and nested-methylation-specific PCR were used to analyze the mRNA expression and promoter methylation of CHD5 genes in a large cohort of breast cancer patients, and to investigate their associations with the clinicopathological features of tumors. CHD5 expression was significantly suppressed in breast cancer tissues compared with normal breast tissues when analyzed by RT-PCR. Furthermore, DNA methylation of CHD5 was more prevalent in breast tumors than in normal tissues. CHD5 mRNA levels correlated with the degree of CHD5 methylation in breast cancer tissues. Clinicopathological correlation analysis revealed that CHD5 promoter methylation was associated with estrogen receptor and progesterone receptor status. Thus, downregulation of CHD5, mediated by abnormal methylation, may contribute to the development and progression of breast cancer.

Isatin inhibits the proliferation and invasion of SH-SY5Y neuroblastoma cells.

Isatin has been shown to initiate apoptotic processes in SH­SY5Y neuroblastoma cells. The aim of the present study was to investigate whether isatin is also able to alter the proliferation and migratory ability of SH­SY5Y cells. The results demonstrated that the proportion of SH­SY5Y cells in G1 phase was significantly increased following treatment with isatin for 48 h with simultaneous downregulation of cyclin D1 expression. In addition, isatin significantly inhibited cell migration and invasion, along with decreases in matrix metalloproteinase (MMP)2 and MMP9 expression. In addition, isatin reduced the levels of phosphorylated signal transducer and activator of transcription 3 (p­STAT3) in a concentration-dependent manner. These results demonstrated that isatin induces G1­phase arrest in SH­SY5Y cells, possibly by decreasing cyclin D1 expression as well as inhibiting their migration and invasiveness, probably by reducing MMP2 and MMP9. These effects may be exerted by isatin via a downregulating the levels of pSTAT3.

Predictive value of CD44 and CD24 for prognosis and chemotherapy response in invasive breast ductal carcinoma.

OBJECTIVE: Cells with unique phenotypes and stem cell-like properties have been found to exist in breast cancer. The aim of the present study was to study the relationship of CD24, CD44, CD44(+)/CD24(-/low) and CD44(-)/CD24(+) tumor phenotypes' with clinico-pathological features, chemotherapy response and with prognosis. METHODS: The study included paraffin-embedded tissues of 140 primary and secondary invasive ductal carcinoma samples. All the patients received routine chemotherapy. Expression of CD24, CD44, ER, PR, and Her2 were assayed immunohistochemically. We applied double-staining immunohistochemistry for the detection of CD44(+)/CD24(-/low), CD44(+)/CD24 (+), CD44(-)/CD24(-) and CD44(-)/CD24(+) cells. The association between the proportions of CD44(+)/CD24(-/low) and CD44(-)/CD24(+) and clinicopathological features, chemotherapy response and with prognosis of these patients was evaluated. RESULTS: CD24 expression was not significantly associated with tumor characteristics, but was significantly associated with poor prognostic variables including ER-, PR-, HER2(+) and triple negative (TN) phenotype; There was no association of CD44 with nodal status, age or HER2 expression. In the correlation analysis, CD24 expression was positively associated with chemotherapy response (P = 0.018), however, CD44 expression was not associated with pathological response to chemotherapy When both markers are considered, the CD44(+)/CD24(-) phenotype had the poor prognosis. The proportion of CD44+/CD24- tumor cells was significantly associated with lymph node involvement, recurrent or metastatic tumors and ER/PR status. High CD44(+)/CD24(-) phenotype had poor response to chemotherapy. The median disease-free survival (DFS) of patients with and without CD44(+)/CD24(-/low) tumor cells were 19.8 ± 2.6 months and 31.7 ± 4.2 months, and the median overall survival (OS) of patients with and without CD44(+)/CD24(-/low) tumor cells were 33.5 ± 2.8 months and 51.4 ± 3.9 months, respectively, and with both univariate and multivariate analyses showing that the proportion of CD44(+)/CD24(-/low) tumor cells was strongly correlated with DFS and OS. However, the CD44(-)/CD24(+), CD44(+)/CD24(+), CD44(-)/CD24 (-) phenotype had no relation with prognosis. CONCLUSION: There was significant correlation between CD44(+)/CD24(-/low) tumor cell prevalence and tumor metastasis, prognosis and chemotherapy response. The CD44(+)/CD24(-) phenotype may be an important factor for malignant relapse following surgical resection and chemotherapy in patients with invasive ductal carcinoma.

The endogenous oxindole isatin induces apoptosis of MCF­7 breast cancer cells through a mitochondrial pathway.

Isatin is an endogenous indole in mammalian tissues and fluids that is expected to have antitumor effects in human breast cancer cells. Human breast cancer cells (MCF-7) were exposed to isatin at various concentrations (0, 50, 100, 200 µmol/l) for 48 h. Apoptotic features were demonstrated by nuclei staining with Hoechst 33258 and flow cytometry. Bcl-2 and Bax mRNA were analyzed via reverse transcription-polymerase chain reaction. Bcl-2, Bax, the inhibitor of caspase-activated DNase (ICAD), and cytochrome c protein were analyzed by western blot analysis. Apoptosis, caspase-9 and -3 activation and mitochondrial depolarization were assayed by flow cytometry. The results showed that isatin induced apoptosis of MCF-7 cells. Furthermore, Bcl-2 expression was decreased and the ratio of Bcl-2 to Bax was significantly decreased by isatin. The mitochondrial transmembrane potential was markedly decreased and the release of cytochrome c into the cytosol was elevated following treatment with isatin. At the same time, caspase-9 and -3 were stimulated, followed by the degradation of ICAD, a caspase-3 substrate.

Decreased expression of the DBC2 gene and its clinicopathological significance in breast cancer: correlation with aberrant DNA methylation.

Loss of DBC2 (deleted in breast cancer 2) gene expression is frequent in breast cancer tissues. This can be explained by homozygous deletions or other mutations in a minority of cases but alternative mechanisms need to be investigated. Here, DBC2 expression was significantly suppressed compared with normal breast tissues in breast cancer tissues when analyzed by RT-PCR. Furthermore, DNA methylation on DBC2 was more prevalent in breast tumors than in normal tissues. DBC2 mRNA levels correlated with the degree of DBC2 methylation in breast cancer tissues and in a breast cancer cell line (T47D). Clinico-pathological correlation analysis showed that DBC2 promoter methylation was associated with tumor-node-metastasis stages II and III/IV, lymph node metastasis, p53 mutation, and HER2-positive status. Thus loss of DBC2 expression is caused by abnormal methylation of DBC2 and might have a role in breast cancer development.

Isatin inhibits proliferation and induces apoptosis of SH-SY5Y neuroblastoma cells in vitro and in vivo.

The purpose of this study was to investigate the anti-tumor effects of the isatin in vitro and in vivo. Human neuroblastoma cells (SH-SY5Y) were exposed to isatin at various concentrations (0, 50, 100, 200 µmol/l) for 48 h. Bcl-2 and Bax mRNA were analyzed via RT-PCR. Bcl-2, Bax, the inhibitor of caspase-activated DNase (ICAD) and cytochrome c protein were analyzed via western blot. Apoptosis, caspase-9, 3 activation and mitochondrial depolarization were assayed by flow cytometry. SH-SY5Y cells were injected into the right side of the mouse armpit. When the neoplasm was detected, the nude mice were randomly divided into four groups and received an injection of DMEM (negative control), 25 or 50mg/kg isatin, or cyclophosphamide (positive control). The inhibitory effects of isatin on the murine xenograft were determined using a growth curve and Bcl-2 and Bax mRNA and protein were studied using RT-PCR and western blot, respectively. The results showed that apoptosis of SH-SY5Y cells was induced by isatin. Furthermore, Bcl-2 expression was decreased and the ratio of Bcl-2 to Bax was significantly decreased by isatin. The mitochondrial transmembrane potential was markedly reduced and the release of cytochrome c into the cytosol was increased after treatment with isatin. Simultaneously, caspase-9, 3 was activated, followed by degradation of ICAD, a caspase-3 substrate. Finally, tumor xenograft growth was markedly suppressed and a decrease was found in Bcl-2 and Bax expression in vivo. These results suggest that isatin can induce apoptosis and inhibit the growth of neuroblastoma cells via the mitochondrial pathway.

Antitumor effects of Isatin on human neuroblastoma cell line (SH-SY5Y) and the related mechanism.

The purpose of the study was to investigate the antitumor effects of Isatin and the related mechanism. Human neuroblastoma cells (SH-SY5Y) were exposed to Isatin at different concentrations for 48 h. Apoptotic features were demonstrated by means of nuclei staining with Hoechst 33258 and flow cytometry with propidium iodide (PI). Expressions of Bcl-2, Bax and vascular endothelial growth factor (VEGF) mRNA were analyzed via RT-PCR. Expressions of Bcl-2, Bax proteins and phosphorylated extracellular signal regulated protein kinases (ERKs, p42/p44) were analyzed via Western blot. Activation of caspase-3 was assayed by flow cytometry with anti-active caspase-3-McAb-PE. VEGF protein was determined by ELISA kits. And the results showed that apoptosis of SH-SY5Y cells were induced by Isatin in a dose-dependent manner. Expressions of Bcl-2, VEGF mRNA and Bcl-2, VEGF proteins were down-regulated, while expressions of Bax mRNA and Bax protein were not changed obviously. Expression of phosphorylated ERKs decreased, but the level of activated caspase-3 increased after treatment of Isatin. These results suggest that Isatin promotes the apoptosis of neuroblastoma cells, therefore, it might be a potential candidate for the treatment of neuroblastoma.

[Effects of isatin on cell cycle arrest and apoptosis of neuroblastoma cell line SH-SY5Y].

BACKGROUND & OBJECTIVE: Isatin (ISA) is a natural material that exists in mammalian body fluids and tissues. ISA could inhibit the growth of tumors, but the mechanism remains unclear. This study aimed to explore the effects of ISA on the cell cycle and apoptosis of neuroblastoma cell line SH-SY5Y. METHODS: Fluorescent staining, flow cytometry, and Western blot were performed to analyze the cell cycle arrest and apoptosis of SH-SY5Y cells after treatment of ISA at different concentrations (0, 100, 200, 400 micromol/L). RESULTS: When treated with 400 micromol/L ISA for 48 h, SH-SY5Y cells showed typical apoptotic morphologic changes including chromatin condensation and DNA fragment. Along with the increase of ISA concentration, Bcl-2 expression was decreased, the ratio of Bcl-2 to Bax was significantly decreased (P<0.05). When treated with ISA (100, 200, 400 micromol/L) for 48 h, the positive rates of activated Caspase-3 in SH-SY5Y cells were significantly higher than that in control SH-SY5Y cells (19.28%, 25.88%, and 33.43% vs. 10.58%, P<0.05). Moreover, inhibitor of caspase-activated DNase (ICAD), the substrate of Caspase-3, was degraded. In addition, the proportion of SH-SY5Y cells at G1 phase was significantly increased with an apparent G1 phase arrest when treated with ISA (100, 200, 400 micromol/L) for 48 h. In the progress of cell cycle arrest induced by ISA, phosphorylated ERK and CDK1 expression were down-regulated (P<0.05). CONCLUSION: ISA can induce apoptosis and G1 phase arrest in SH-SY5Y cells, possibly by decreasing Bcl-2/Bax, activating Caspase-3 and down-regulating the expression of phosphorylated ERK and CDK1.