Xinghua Long

SATB1 is Correlated with Progression and Metastasis of Breast Cancers: A Meta-Analysis

Background/Aims: Several researches have evaluated the significance of SATB1 (Special AT-rich sequence binding protein 1) expression in breast cancers (BCs), but the results have been disputed, especially in the aspects of clinicopathological features and prognosis. Therefore, our study aimed to use a meta-analysis to summarize the clinical and prognostic relevance of SATB1 gene expression in BCs. Methods: A literature search of PubMed, EMBASE, Cochrane library, Chinese Wanfang and CNKI was performed to identify eligible studies. Ten studies total, comprising 5,185 patients (1,699 SATB1-positive and 3,486 SATB1-negative), were enrolled in our study, which was performed using Revman5.3 Software and Stata11.0 Software. Results: This meta-analysis showed that the expression of SATB1 was significantly higher in breast cancer than in normal tissues (OR = 12.28; 95%CI = 6.01-25.09), and was statistically related to several clinicopathological parameters, including lymph node metastasis (OR = 1.55, 95%CI = 1.01-2.39) and Tumor Node Metastasis(TNM) stage (OR = 0.35, 95%CI = 0.22-0.56). However, the level of SATB1 was not statistically associated with the age (OR = 1.13, 95%CI = 0.87-1.46), tumour size (OR = 0.72, 95%CI = 0.44-1.19), estrogen receptor (OR = 0.78, 95%CI = 0.55-1.09), progesterone receptor (OR = 0.64, 95%CI = 0.32-1.29), HER2 status (OR=1.98, 95%CI = 0.74-5.30), and histological type (OR = 0.49, 95%CI = 0.22-1.11). Conclusion: High expression of SATB1 was significantly correlated with tumourigenesis and metastasis of BCs, indicating poor prognosis for patients. SATB1 could serve as a potential marker for detection and prognosis evaluation of breast cancers.

Androgen Receptor, EGFR, and BRCA1 as Biomarkers in Triple-Negative Breast Cancer: A Meta-Analysis

Objective. More and more evidences demonstrate that androgen receptor (AR), epidermal growth factor receptor (EGFR), and breast cancer susceptibility gene 1 (BRCA1) have unique clinical implications for targeted therapy or prognosis in triple-negative breast cancer (TNBC). Therefore, we conducted a meta-analysis to summarize the possible associations. Methods. We retrieved published articles about AR, EGFR, and BRCA1 in TNBC from PubMed and EMBASE. The analysis was performed with Rev-Man 5.2 software. Results. A total of 38 articles were eligible for the meta-analysis. Our study showed that the expression level of EGFR (OR = 6.88, P < 0.00001) and the prevalence of BRCA1 mutation (RR = 5.26, P < 0.00001) were higher in TNBC than non-TNBC. In contrast, the expression level of AR was lower in TNBC than non-TNBC (OR = 0.07, P < 0.00001). In the subgroup related to EGFR expression, the level of EGFR expression was significantly increased in Asians (OR = 9.60) compared with Caucasians (OR = 5.53) for TNBC patients. Additionally, the prevalence of BRCA1 mutation in Asians (RR = 5.43, P < 0.00001) was higher than that in Caucasians (RR = 5.16, P < 0.00001). Conclusions. The distinct expression of AR and EGFR and the prevalence of BRCA1 mutation indicated that AR, EGFR, and BRCA1 might be unique biomarkers for targeted therapy and prognosis in TNBC.

The Clinicopathological Significance of MicroRNA-155 in Breast Cancer: A Meta-Analysis

Objective. Previous studies demonstrated that the associations between expression level of microRNA-155 (miR-155) and clinicopathological significance of breast cancer remained inconsistent. Therefore, we performed a meta-analysis based on eligible studies to summarize the possible associations. Methods. We identified eligible studies published up to May 2014 by a comprehensive search of PubMed, EMBASE, CNKI, and VIP databases. The analysis was performed with RevMan. 5.0 software. Results. A total of 15 studies were included. The results of meta-analysis showed that miR-155 was positively correlated with breast cancer with standardized mean difference (SMD) = 1.22. Elevated miR-155 was found in Her-2 positive or lymph node metastasis positive, or p53 mutant type breast cancer. But the result showed to be insignificant in TNM comparison. With respect to estrogen receptor alpha (ER) and progesterone receptor (PR) status, both of them showed significant associations with SMD = −1.2 and −1.85, respectively. Conclusion. MiR-155 detection might have a diagnostic value in breast cancer patients. It might be used as an auxiliary biomarker for different clinicopathological breast cancer.

Differential microRNA expression profiles in tamoxifen-resistant human breast cancer cell lines induced by two methods

Tamoxifen (TAM) resistance has become a severe problem for endocrine therapy of breast cancer. The present study investigated the association between microRNA (miRNA) expression and TAM resistance in breast cancer. The TAM-resistant breast cancer MCF-7C and MCF-7T cell lines were established using the human breast cancer cell line MCF-7 as the parental cell line and 4-hydroxytamoxifen (OHT) as the screening drug in vitro. The MCF-7C cell line was established by dose stepwise induction beginning with a low concentration of OHT; the MCF-7T cell line was established by temporal stepwise induction beginning with a high concentration of OHT. Differential miRNA expression profiles between TAM-sensitive (MCF-7) and TAM-resistant (MCF-7C and MCF-7T) breast cancer cell lines were detected and analyzed using RNA sequencing technology. The results of western blot analysis indicated that the level of ERα protein expression in drug-resistant cells was significantly increased. A total of 1,646 miRNAs were detected in all samples, including 1,376 known miRNAs and 270 predicted miRNAs. There were 118 miRNAs expressed at significantly different levels between MCF-7C and MCF-7 cells (P<0.05); among them, 67 miRNAs were upregulated (P<0.05) and 51 miRNA were downregulated (P<0.05). There were 42 miRNAs expressed at significantly different levels between MCF-7T and MCF-7 (P<0.05); among them, 23 miRNAs were upregulated (P<0.05) and 19 miRNAs were downregulated (P<0.05). There were 126 miRNAs with significant differences between MCF-7C and MCF-7T (P<0.05); among them, 76 miRNAs were upregulated (P<0.05) and 50 miRNAs were downregulated. On the basis of the results of the present study, we hypothesize that miR-21, miR-146a, miR-148a, miR-34a and miR-27a may serve important roles in mediating TAM resistance in breast cancer, and have potential as therapeutic targets for TAM-resistant breast cancer.

miR-145 overexpression triggers alteration of the whole transcriptome and inhibits breast cancer development

Cumulative evidence has associated microRNA (miRNA) with cancer development, and among those miRNAs, miR-145 has been identified as an anti-oncomiRNA. However, the comprehensive mechanisms of action of miR-145 in breast cancer development have not yet been fully elucidated. Herein, we performed next-generation sequencing to detect the expression profiles of the transcriptome and conducted cellular function experiments after miR-145 overexpression. The results verified the inhibitory effects of miR-145 on breast cancer cell proliferation, colony formation, migration and invasion. Sequencing data revealed that miR-145 triggered the alteration of the whole transcriptome and further led to regulation of the competing endogenous RNA (ceRNA) network. Our study also identified a list of 49 target mRNAs of miR-145 and specific non-coding RNAs, which could be utilized as potential breast cancer biomarkers. This study might serve as a significant platform for further research on miR-145 along with the ceRNA network in breast cancer.

Differential Expression Profiles of the Transcriptome in Breast Cancer Cell Lines Revealed by Next Generation Sequencing

Background/Aims: As MCF-7 and MDA-MB-231 cells are the typical cell lines of two clinical breast tumour subtypes, the aim of the present study was to elucidate the transcriptome differences between MCF-7 and MDA-MB-231 breast cancer cell lines. Methods: The mRNA, miRNA (MicroRNA) and lncRNA (Long non-coding RNA) expression profiles were examined using NGS (next generation sequencing) instrument Illumina HiSeq-2500. GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analyses were performed to identify the biological functions of differentially expressed coding RNAs. Subsequently, we constructed an mRNA-ncRNA (non-coding RNA) targeting regulatory network. Finally, we performed RT-qPCR (real-time quantitative PCR) to confirm the NGS results. Results: There are sharp distinctions of the coding and non-coding RNA profiles between MCF-7 and MDA-MB-231 cell lines. Among the mRNAs and ncRNAs with the most differential expression, SLPI, SOD2, miR-7, miR-143 and miR-145 were highly expressed in MCF-7 cells, while CD55, KRT17, miR-21, miR-10b, miR-9, NEAT1 and PICSAR were over-expressed in MDA-MB-231 cells. Differentially expressed mRNAs are primarily involved in biological processes of locomotion, biological adhesion, ECM-receptor interaction pathway and focal adhesion. In the targeting regulatory network of differentially expressed RNAs, mRNAs and miRNAs are primarily associated with tumour metastasis, but the functions of lncRNAs remain uncharacterized. Conclusion: These results provide a basis for future studies of breast cancer metastasis and drug resistance.

Association Between MGMT Promoter Methylation and Breast Cancer: a Meta-Analysis

Background/Aims: Numerous studies have suggested that the promoter methylation status of O6-methylguanine-DNA methyltransferase (MGMT) is significantly associated with breast cancer. However, these studies have not demonstrated consistent results. Methods: To obtain more accurate results for this possible association, we performed a meta-analysis-based study using the relevant data. A total of 14 articles were included in this meta-analysis. Results: Our study showed that the frequency of MGMT promoter methylation was significantly higher in patients with breast cancer than non-breast cancer subjects with an Odds Ratio (OR) of 4.47, a 95% Confidence Interval (CI) ranging between 1.95 - 10.25 and a P value of 0.0004. Moreover, MGMT methylation was significantly associated with the negative expression of the MGMT protein (OR = 4.65, 95%CI = 2.66 - 8.12, P < 0.00001), Oestrogen Receptor (ER)-negative tumours (OR = 1.79, 95%CI = 1.09 - 2.93, P = 0.02), postmenopausal status (OR =1.84, 95%CI = 1.18 - 2.87, P = 0.007) and histological grade III tumours (OR = 2.49, 95%CI = 1.53 - 4.07, P = 0.0003) in breast cancer patients. However, breast cancer was not significantly correlated with lymph node metastasis (OR = 1.19, 95%CI = 0.83 - 1.70, P = 0.35), Progesterone Receptor (PR) status (OR = 1.08, 95%CI = 0.58 - 2.00, P = 0.81), Human epidermal growth factor receptor - 2（HER-2/neu）status (OR = 1.01, 95%CI = 0.65 - 1.57, P = 0.97), P53 mutation (OR = 1.30, 95%CI = 0.76 - 2.21, P = 0.34) and age > 50 (OR = 1.07, 95%CI = 0.46 - 2.51, P = 0.88). Conclusions: Our study suggests that MGMT promoter methylation may be an early biomarker for the diagnosis of breast cancer.

Quantitative assessment of the association between APC promoter methylation and breast cancer

Adenomatous polyposis coli (APC) is an important tumor suppressor gene in breast cancer. However, there were inconsistent conclusions in the association between APC promoter methylation and breast cancer. Hence, we conducted a meta-analysis to quantitatively assess the clinicopathological significance and diagnosis role of APC methylation in breast cancer. In total, 3172 samples from 29 studies were performed in this study. The odds ratio (OR) of APC methylation was 5.92 (95% CI = 3.16–11.07) in breast cancer cases compared to controls,. The APC promoter methylation was associated with cancer stage (OR = 0.47, 95% CI = 0.28–0.80, P = 0.006), lymph node metastases (OR = 0.55, 95% CI = 0.36–0.84, P = 0.005) and ER status (OR = 1.34, 95% CI = 1.03–1.73, P = 0.003) in breast cancer. Furthermore, the sensitivity and specificity for all included studies were 0.444 (95% CI: 0.321–0.575, P < 0.0001) and 0.976 (95% CI: 0.916–0.993, P < 0.0001), respectively. These results suggested that APC promoter methylation was associated with breast cancer risk, and it could be a valuable biomarker for diagnosis, treatment and prognosis of breast cancer.