lncRNA GAS5-promoted apoptosis in triple-negative breast cancer by targeting miR-378a-5p/SUFU signaling.

PURPOSE: Long-chain noncoding RNAs (lncRNAs) are involved in regulating the sensitivity of cancer cells to chemotherapeutic drugs, but the specific mechanism of action is not well understood. The aim of this study was to investigate the effect of lncRNA growth-stasis specific transcript 5 (GAS5) on triple-negative breast cancer (TNBC). METHODS: Quantitative real-time polymerase chain reaction and flow cytometry were used to screen lncRNA associated with tumor resistance. Double luciferase reporter gene assay, flow cytometry, and Western blot assay were used to determine whether miRNA 378a-5p and SUFU were involved in tumor cell apoptosis induced by lncRNA GAS5. A mouse model of subcutaneous xenografts was established to investigate the relationship between lncRNA GAS5 and tumor resistance in vivo. RESULTS: In this study, the expression of lncRNA GAS5 was significantly downregulated in cells treated with paclitaxel (PTX) or cisplatin (CIS). Furthermore, TNBC cells with low expression of lncRNA GAS5 had a lower percentage of apoptosis under stress conditions, especially in serum-free medium. More interestingly, the expression level of lncRNA GAS5 in TNBC patients was associated with tumor resistance to PTX and CIS. In addition, RNA immunoprecipitation experiments confirmed that lncRNA GAS5 and miR-378 could directly bind to each other. Moreover, the miR-378a-5p target of SUFU could promote lncRNA GAS5-induced apoptosis of TNBC cells. Finally, lncRNA GAS5 overexpressed MDA-231R could enhance the sensitivity of TNBC to PTX. CONCLUSION: The above results confirmed that lncRNA GAS5 could induce apoptosis in TNBC cells by targeting miR-378a-5p/SUFU signaling.

Presence of White Matter Lesions Associated with Diabetes-Associated Cognitive Decline in Male Rat Models of Pre-Type 2 Diabetes.

BACKGROUND The aim of this study was to determine the association between white matter lesions (WML) and diabetes-associated cognitive decline (DACD) in rat models of type 2 diabetes (T2DM). MATERIAL AND METHODS Sixty Sprague-Dawley male rats were divided into 4 groups: control, control+metformin, T2DM, and T2DM+metformin groups. The T2DM groups were fed a diet high in fat and glucose to induce impaired glucose tolerance (IGT) and then were injected with streptozotocin to induce T2DM. The Morris water maze test was used to evaluate cognitive function. Brain diffusion tensor imaging scans were performed for WML. The expression of myelin basic protein (MBP), oligodendrocyte transcription factor 1 (OLIG1), and OLIG2 (markers of brain damage and repair) was determined using immunofluorescence. After IGT, the fractional anisotropy (FA) values of the right thalamus area were significantly lower in both T2DM groups compared with controls. RESULTS Eight weeks after streptozotocin injection, the FA values of the thalamus were lower in the T2DM (bilateral thalamus) group and T2DM+metformin (left thalamus) group than in controls, while the FA values in the left thalamus area were lower in the T2DM+metformin group than in the control and control+metformin groups. The maze escape latency was longer and the number of rats passing through the platform was smaller in the T2DM and T2DM+metformin groups than in the control group. MBP levels were lower and OLIG1 and OLIG2 levels were higher in both T2DM groups than in controls. CONCLUSIONS WML is associated with DACD and appears before the onset of T2DM and signs of DACD and plays a role in diabetes-associated cognitive decline. Metformin reduces WMLs but does not rescue cognitive dysfunction.

SNHG1 contributes to proliferation and invasion by regulating miR-382 in breast cancer.

Introduction: Long non-coding RNAs (lncRNAs) are key regulators in multiple cancers. lncRNA, SNHG1, was shown to be associated with tumorigenesis. However, little is known about the role SNHG1 plays in breast cancer. The aim of the study was to study the role and underlying mechanism of SNHG1 regulation in breast cancer. Methods: Quantitative real-time PCR was used to measure the levels of SNHG1, miR-382 and ZEB1 levels in breast cancer tissue or cells. The proliferation, colony formation, migration and invasion of breast cancer cells, under SNHG1 knockdown achieved by transfection of SNHG1-specific siRNAs, were assessed by Cell Counting Kit-8, colony forming, scratch wound and transwell assays. Bioinformatical analysis and luciferase assay were used to explore the interaction between SNHG1 and its potential miRNA target. Western blot was used to evaluate the expression of epithelial-to-mesenchymal transition (EMT) markers. MDA-MB-231 cells with or without SNHG1 knockdown were used to initiate tumor xenografts in vivo. Tumor growth and expression of SNHG1, miR-382-5p and EMT markers were evaluated. Results: SNHG1 upregulation was observed in breast cancer tissues and cells. Knockdown of SNHG1 attenuated breast cancer proliferation, colony formation, migration and invasion. A miRNA, miR-382-5p, was identified as the target of SNHG1. A reciprocal negative regulation was found between SNHG1 and miR-382-5p. SNHG1 knockdown attenuated EMT both in vitro and in vivo. miR-382-5p transfection reversed the tumor-promoting role by SNHG1. In vivo, SNHG1 knockdown decreased breast tumor growth. Conclusion: SNHG1 promotes breast cancer through the regulation of miR-382-5p and EMT markers. Our results report SNHG1 as a novel miRNA that govern the progression of breast cancer, providing a potential new therapeutic target in breast cancer.

Dual-Targeting of miR-124-3p and ABCC4 Promotes Sensitivity to Adriamycin in Breast Cancer Cells.

AIMS: Increasing evidence links the abnormal expression of microRNAs and ATP-binding cassette subfamily C member 4 (ABCC4) with tumor development and progression, as well as with chemoresistance. Our aims were to determine the therapeutic potential of targeting both miR-124-3p and ABCC4 in breast cancer cells and to determine if duel targeting increased their sensitivity to chemotherapeutic drugs, in vitro. MATERIALS AND METHODS: The expression of the ABCC4 protein and miR-124-3p were detected, respectively, by immunohistochemical staining and quantitative real-time polymerase chain reaction in breast cancer tumor tissue, MCF-7 and MCF-7-ADR cell lines. Suppression of ABCC4 expression and miR-124-3p overexpression were performed in MCF-7-ADR cell lines. Western blot assays were used to detect expression of ABCC4 and permeability glycoprotein 1/multi-drug resistance protein 1 (P-gp) in cells. Cell Counting Kit-8, flow cytometry, transwell, and scratch assays were conducted to detect cell proliferation, cell cycle, invasion, and migration of cells. RESULTS: We found that ABCC4 protein expression was significantly increased, while the miR-124-3p level was significantly decreased in breast cancer tissue and cell lines. Tumor size and clinical tumor node metastasis stage were significantly correlated with elevated expression of ABCC4 and decreased expression of miR-124-3p. Interestingly, ABCC4 expression was significantly increased in MCF-7-ADR cells, while miR-124-3p level was significantly decreased compared with MCF-7 cells. The inhibition of ABCC4 and miR-124-3p overexpression both led to a significant decrease in cell proliferation, invasion, and migration of MCF-7-ADR cells, and combination of suppression of ABCC4 with miR-124-3p overexpression had a synergistic inhibitory effect. Our results further demonstrated that inhibition of ABCC4 expression and overexpression of miR-124-3p significantly enhanced the sensitivity to adriamycin (ADR) in MCF-7-ADR cells, and that simultaneous dual-targeting of miR-124-3p and ABCC4 had a stronger promotive effect on the sensitivity to ADR in MCF-7-ADR cells. Moreover, western blot analysis showed that miR-124-3p overexpression significantly inhibited P-gp expression in MCF-7-ADR cells. CONCLUSION: Our data demonstrate that the combination of downregulation of ABCC4 with overexpression of miR-124-3p significantly increased sensitivity to ADR in MCF-7-ADR cells. This finding suggests that similar dual targeting may serve as a means to enhance therapies for drug-resistant breast cancers.

Silencing of the long non-coding RNA RHPN1-AS1 suppresses the epithelial-to-mesenchymal transition and inhibits breast cancer progression.

Breast cancer (BC) is a frequently diagnosed malignancy in women. Increasing evidence implicates mis-expression of the long non-coding RNA (lncRNA) RHPN1 antisense RNA 1 (RHPN1-AS1) in the development of multiple cancer types. However, little is known about the expression pattern and function of lncRNA RHPN1-AS1 in the pathobiology of BC. We evaluated the expression of RHPN1-AS1 in The Cancer Genome Atlas dataset, and analyzed associations between RHPN1-AS1 expression and clinicopathologic features of BC patients. Additionally, we compared the expression of RHPN1-AS1 between BC and breast non-tumor samples via quantitative real-time polymerase chain reaction, and in situ hybridization, and evaluated the prognostic value of RHPN1-AS1 in a BC tissue microarray. We examined the impact of RHPN1-AS1 knockdown on proliferation, migration, and invasion of BC cells in vitro, and tumor growth in vivo. Bioinformatics analyses were used to predict the function of RHPN1-AS1 in BC. RHPN1-AS1 expression was upregulated in BC and elevated RHPN1-AS1 expression was strongly associated with poor prognosis of BC patients. Moreover, both univariate and multivariate analyses revealed that RHPN1-AS1 was a significant and independent predictor of BC prognosis. Functionally, RHPN1-AS1 silencing attenuated BC cell proliferation, migration, and invasion in vitro, and reduced tumor growth in xenograft models. Furthermore, RHPN1-AS1 silencing was associated with a decrease in the expression of epithelial-to-mesenchymal transition (EMT) markers in the xenograft tumors, suggesting that RHPN1-AS1 promotes invasion in BC cells by enhancing EMT. These findings suggest that RHPN1-AS1 is a potential prognostic biomarker and therapeutic target for BC.

Overexpression of CBX2 in breast cancer promotes tumor progression through the PI3K/AKT signaling pathway.

Breast cancer is the second leading cause of cancer-related death among women worldwide. Emerging evidence suggests that chromobox homolog 2 (CBX2) is overexpressed in breast cancer and plays an essential role in tumor progression. However, its expression and functional roles in breast cancer development and progression require further exploration. Here, we evaluated CBX2 expression in breast cancer using mRNA expression data from the TCGA database; CBX2 expression was upregulated in breast cancer. Furthermore, upregulated CBX2 expression was significantly associated with poorer overall survival (OS) and progression-free survival (PFS) of breast cancer patients. Immunohistochemical analysis of CBX2 expression in a tissue microarray (TMA) cohort yielded concordant results. Univariate and multivariate analyses showed that elevated CBX2 expression was significantly and independently associated with poorer OS of patients in this TMA cohort. Additionally, we performed in vitro functional assays to evaluate the proliferation, migration, and invasion abilities of breast cancer cell lines wherein CBX2 was knocked down using short hairpin RNA (shRNA). CBX2 silencing inhibited cell proliferation, migration, and invasion in vitro. Furthermore, knockdown of CBX2 markedly reduced breast tumorigenesis in xenograft mouse models. Functional and pathway enrichment analyses indicated a positive correlation between high CBX2 expression and activation of the PI3K/AKT pathway, which were further confirmed by western blot and immunohistochemical analyses of mouse tumors. Our findings indicate that CBX2 is a potential prognostic biomarker and therapeutic target for breast cancer.

Intervention of selenium on apoptosis and Fas/FasL expressions in the liver of fluoride-exposed rats.

Fluorosis is a major public health problem in numerous areas around the world, including China. To alleviate this problem, selenium has been used. In this study, we aimed to investigate the influence of selenium on apoptosis in fluorosis-affected rat livers and determine the optimal selenium concentration in drinking water to fight fluorosis. The protein levels of Fas in NaF and NaF+Se (0.375 and 0.75 mg/L) groups as well as FasL in NaF, Se (0.75 and 1.5 mg/L), and NaF+Se (0.375 mg/L) groups were significantly increased compared with those in the control group. The mRNA levels of Fas in NaF and Se (1.5 mg/L) groups as well as FasL in NaF and NaF+Se (0.375 mg/L) groups were significantly increased. The protein levels of Fas in NaF+Se (1.5 mg/L) group and FasL in three NaF+Se groups were significantly decreased compared with those in the NaF group. The mRNA levels of Fas in the three NaF+Se groups and FasL in NaF+Se (0.75 and 1.5 mg/L) groups were significantly decreased. Compared with the control group, activity of GSH-Px, and SOD in the NaF group decreased obviously and MDA content increased obviously; activity of SOD in 1.5 mg/L Se group decreased obviously. Compared with the NaF group, activity of GSH-Px in NaF+Se (1.5 mg/L) group significantly increased, and MDA content decreased obviously. Thus, fluoride induced apoptosis in the liver, thereby causing liver damage in the rats. Selenium could alleviate fluorosis-induced liver injury. In particular, selenium at 1.5 mg/L is considered the optimum concentration against fluorosis.

Effect of selenium on fluoride-induced changes in synaptic plasticity in rat hippocampus.

This study was conducted to further explore the effect of selenium on fluoride-induced changes in the synaptic plasticity in rat hippocampus. Animals were randomly divided into control group, F group (sodium fluoride: 50 mg/L), three Se groups (sodium selenite: 0.375, 0.75, and 1.5 mg/L), and three F+Se groups (sodium fluoride: 50 mg/L; sodium selenite:0.375, 0.75, and 1.5 mg/L) and subjected to an exposure time of 6 months. The changes in synaptic plasticity in rat hippocampus were observed by electron microscopy. Compared with the fluoride group, the length of the synaptic active zone and the thickness of the postsynaptic density (PSD) increased significantly, whereas the width of the synaptic cleft decreased with high significance in the F+Se (0.75 mg/L) group. Moreover, the nitric oxide synthase activity and the nitric oxide content in the hippocampus decreased significantly in the F+Se (0.75 and 1.5 mg/L) groups. Furthermore, reverse transcriptase polymerase chain reaction and Western blot analyses showed that postsynaptic density-93 (PSD-93) expression in the hippocampus was increased significantly, whereas postsynaptic density-95 (PSD-95) expression decreased significantly in the fluoride group compared with the control group. The PSD-93 expression was inhibited in the three F+Se groups, whereas the opposite result was observed in PSD-95 expression. Based on the results, the optimal selenium dosage range that can antagonize the neurotoxicity of fluorosis is from 0.75 to 1.5 mg/L. The changes in PSD-93 expression may be the key factor to fluoride-induced central nervous toxicity and the effect of selenium intervention.

Effects of selenium intervention on chronic fluorosis-induced renal cell apoptosis in rats.

This study aims to explore the effect of selenium in fluoride-induced renal cell apoptosis in rats and determine the optimal level of selenium in drinking water to prevent fluorosis. Experimental animals were divided into a control group, a sodium fluoride-treated group (NaF, 50 mg/L), three sodium selenite-treated groups (Na2SeO3, 0.375, 0.75, and 1.5 mg/L), and three selenium + NaF-treated groups (Na2SeO3, 0.375, 0.75, and 1.5 mg/L; NaF, 50 mg/L). Ultrastructural changes in the kidney tissues of each group were observed by transmission electron microscopy. Apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay and the expressions of Bcl-2 and Bax proteins were detected by immunohistochemical methods. The expressions of Bcl-2 and Bax mRNA were detected by reverse transcription-polymerase chain reaction. The results showed that Bcl-2, Bax, and Bax/Bcl-2 protein expressions in the fluoride and high selenium groups were highly elevated compared with the control group (P < 0.01). Bax expression in the low selenium group and Bcl-2, Bax, and Bax/Bcl-2 protein expressions in the moderate selenium groups were observably elevated (P < 0.05). Bax and Bax/Bcl-2 expressions in the fluoride group and Bax mRNA expression in the high selenium group were highly elevated (P < 0.01). Bax/Bcl-2 mRNA expression in the high selenium group was also highly elevated (P < 0.05). Compared with the fluoride group, the group treated with low selenium has Bax protein expression that was observably reduced (P < 0.05); the group treated with moderate selenium has Bcl-2 protein expression that was observably elevated (P < 0.05), Bax protein expression that was highly reduced (P < 0.01), and Bax/Bcl-2 protein expression that was observably reduced (P < 0.05); the group treated with high selenium has Bcl-2 protein expression that was highly elevated (P < 0.01), Bax protein expression that was highly elevated (P < 0.01), and Bax/Bcl-2 protein expression that was highly reduced (P < 0.01); the groups treated with moderate selenium and high selenium have Bax mRNA expression that was highly reduced (P < 0.01), and the groups treated with high selenium have Bax/Bcl-2 mRNA expression that was observably reduced (P < 0.05). Selenium may inhibit the apoptosis of renal cells in fluorosis rats by regulating the expressions of Bcl-2 and Bax. The optimal dose of Na2SeO3 to protect against fluoride-induced renal cell apoptosis was determined to be 1.5 mg/L.