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Breast cancer is the leading cause of cancer death in women worldwide. Long non-coding RNA small nucleolar RNA host gene 1 ( SNHG1 ) has been reported to be involved in human diseases, including cancer. Here, we found that SNHG1 expression was significantly upregulated in human breast cancer tissues and cell lines. We explored the function of SNHG1 in breast cancer cells using in vitro and in vivo experiments and found that SNHG1 promotes breast cancer metastasis and proliferation. The potential molecular mechanism of SNHG1 in breast cancer cells may involve SNHG1 acting as a sponge of miR-193a-5p to activate the expression of the oncogene HOXA1 . In summary, our study reveals a novel SNHG1 / miR-193a-5p/HOXA1 competing endogenous RNA regulatory pathway in breast cancer progression and may provide new strategies for breast cancer therapy.

Objective: The aim was to investigate the lncRNA KB-1471A8.2 function in ovarian cancer progression and paclitaxel resistance. Methods: The expression and distribution of KB-1471A8.2 was detected by qRT-PCR. The cell proliferation, apoptosis, invasion, migration and chemoresistance were analyzed by CCK8 assay, flow cytometry and transwell assay. The expression of DEPTOR, whose sequence is reverse overlapped with KB-1471A8.2 was analyzed by qRT-PCR, western blot and immunofluorescence. The cell cycle and the cell cycle related gene expression were analyzed by flow cytometry and qRT-PCR, respectively. Results: KB-1471A8.2 was significantly downregulated in both ovarian cancer tissues and chemoresistant ovarian cancer cells. Overexpression of KB-1471A8.2 significantly inhibited the proliferation, invasion, migration, and paclitaxel resistance, and increased the apoptosis of ovarian cancer cells. KB-1471A8.2 was mainly distributed in the nucleus of ovarian cancer cells. KB-1471A8.2 overexpression significantly decreased the S phase cell ratio, increased the G0/G1 phase cell ratio, but not affected the expression and distribution of DEPTOR. However, cyclin-dependent kinase 4 ( CDK4 ), which is an important regulator of G1/S transition, was significantly decreased in KB-1471A8.2-overexpressed ovarian cancer cells. Conclusion: KB-1471A8.2 could significantly inhibit the development and paclitaxel resistance of ovarian cancer cells, at least partly, by suppressing CDK4 expression.

Breast cancer is the most commonly diagnosed cancer and the leading cause of cancer death in females worldwide. Chemoresistance has been a major reason for the drug therapy failure. The present study performed a microarray analysis between MCF‑7 and MCF‑7/adriamycin (ADR) cells, and intended to identify long non‑coding (lnc)RNA expression character in drug resistant breast cancer cells. MCF‑7/ADR cells were induced from MCF‑7 cells via pulse‑selection with doxorubicin for 4 weeks, and the resistance to doxorubicin of ADR cells was confirmed by MTT assay. Microarray analysis was performed between MCF‑7 and MCF‑7/ADR cells. Total RNA was extracted from the two cell lines respectively and was transcribed into cDNA. The results of the microarray were verified by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). Gene Ontology (GO) and pathways analysis were conducted to enrich the dysregulated lncRNAs presented in the microarray results. Compared to the MCF‑7 cells, 8,892 lncRNAs were differentially expressed in MCF/ADR cells (absolute fold‑change >2.0). A total of 32 lncRNAs were selected for RT‑qPCR by fold‑change filtering, standard Student's t‑test, and multiple hypothesis testing. Among the dysregulated lncRNAs, AX747207 was prominent because its associated gene RUNX3 was previously reported to be relative to malignant tumor chemoresistance. GO analysis results also indicated some biological processes and molecular functions linked to chemoresistance. The pathway enrichment results provided some potential pathways associated with chemoresistance. In the present study, the authors intended to identify lncRNA expression character in drug resistant cell line MCF‑7/ADR, corresponding to the parental MCF‑7 cell line. In addition, the study identified the lncRNA AX747207, and its potential targeted gene RUNX3, may be related to chemoresistance in breast cancer. These results may new insights into exploring the mechanisms of chemoresistance in breast cancer.

Transfer RNAs (tRNAs) were traditionally considered to participate in protein translation. Recent studies have identified a novel class of small non-coding RNAs (sncRNAs), produced by the specific cleavage of pre- and mature tRNAs, which have been named tRNA-derived fragments. tRNA-derived fragments are classified into diverse subtypes based on the different cleavage positions of the pre- and mature tRNAs. Recently, accumulated evidence has shown that these tRNA-derived fragments are frequently dysregulated in several cancers. Several tRNA-derived fragments were found to participate in cell proliferation, apoptosis, and invasive metastasis in several malignant human tumors. These dysregulated fragments are able to bind both Argonaute proteins and Piwi proteins to regulate gene expression. Some of the newly identified tRNA-derived fragments have been considered as the new biomarkers and therapeutic targets for the treatment of cancer. This review summarizes the biogenesis and biological functions of different subtypes of tRNA-derived fragments and discusses their molecular mechanisms in cancer progression., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Long noncoding RNA (lncRNA) has been recognized as a regulator of gene expression, and the dysregulation of lncRNAs is involved in the progression of many types of cancer, including epithelial ovarian cancer (EOC). To explore the potential roles of lncRNAs in EOC, we performed lncRNA and mRNA microarray profiling in malignant EOC, benign ovarian cyst and healthy control tissues. In this study, 663 transcripts of lncRNAs were found to be differentially expressed in malignant EOC compared with benign and normal control tissues. We also selected 18 altered lncRNAs to confirm the validity of the microarray analysis using quantitative real-time PCR (qPCR). Pathway and Gene Ontology (GO) analyses demonstrated that these altered transcripts were involved in multiple biological processes, especially the cell cycle. Furthermore, Series Test of Cluster (STC) and lncRNA-mRNA co-expression network analyses were conducted to predict lncRNA expression trends and the potential target genes of lncRNAs. We also determined that two antisense lncRNAs (RP11-597D13.9 and ADAMTS9-AS1) were associated with their nearby coding genes (FAM198B, ADAMTS9), which participated in cancer progression. This study offers helpful information to understand the initiation and development mechanisms of EOC.

The oncogene, mouse double minute 2 (MDM2), has been implicated in the pathogenesis of numerous cancers. In this study, we investigated the role of MDM2 in epithelial-to-mesenchymal transition (EMT) and the underlying mechanisms in breast cancer cells in vitro and in vivo. The results showed that up-regulation of MDM2 in MCF-7 cells altered the cell morphology to a mesenchymal phenotype. Knockdown of MDM2 in MDA-MB-231 cells altered the cell morphology to the epithelial phenotype. In addition, overexpression of MDM2 increased the expression of N-cadherin and Vimentin and decreased the expression of E-cadherin, at both the mRNA and protein levels, in vitro and in vivo. Conversely, down-regulation of MDM2 decreased the expression of N-cadherin and Vimentin, and increased the expression of E-cadherin in vitro. Furthermore, MDM2 up-regulated both the mRNA and protein expression of Snail in vitro and in vivo. Knockdown of Snail almost abolished MDM2 induced EMT in vitro. Finally, we found that MDM2 expression correlated with EMT markers and Snail: Snail expression was inversely associated with E-cadherin in human breast cancer samples. Our findings demonstrated that MDM2 induces EMT by enhancing Snail expression in vitro and in vivo. Thus, MDM2 may be a potential target for therapy against human metastatic breast cancer., Competing Interests: The authors declare that they have no competing interests.

Heterogeneity is the major obstacle to breast cancer target therapy. Classification of breast cancer with significant biological process may reduce the influence of heterogeneity of intrinsic tumor. We used survival analysis to filter 95 gene sets and classify 638 breast cancer samples into two subtypes based on those gene sets associated with prognosis. Clinical outcome of two subtypes were evaluated with disease-free survival, distant metastasis-free survival, and overall survival levels in three databases and ER+, PR+ HER2+, and TNBC groups. We established a novel classification with 95 prognostic gene sets. In the training and validation cohorts, the subtype 1 was characterized by significant gene sets associated with regulation of metabolic process and enzyme activity and predicted obviously improved clinical outcome than subtype 2, which was enriched by tumor cell division, mitosis, and cell cycle-related gene sets (P < 0.05). When evaluated prognostic impact of subtypes in ER+, PR+ HER2+, and TNBC groups, we found that patients in subtype 1 showed better prognosis in ER+ and PR+ groups (P < 0.05) but had no difference from prognosis of subtype 2 in HER2+ and TNBC groups. These findings may have implications in understanding of breast cancer and filtering effective therapeutic strategies for targeted therapy.

The human uterine cervix carcinoma is one of the most well-known malignancy reproductive system cancers, which threatens women health globally. However, the mechanisms of the oncogenesis and development process of cervix carcinoma are not yet fully understood. Long non-coding RNAs (lncRNAs) have been proved to play key roles in various biological processes, especially development of cancer. The function and mechanism of lncRNAs on cervix carcinoma is still rarely reported. We selected 3 cervix cancer and normal cervix tissues separately, then performed lncRNA microarray to detect the differentially expressed lncRNAs. Subsequently, we explored the potential function of these dysregulated lncRNAs through online bioinformatics databases. Finally, quantity real-time PCR was carried out to confirm the expression levels of these dysregulated lncRNAs in cervix cancer and normal tissues. We uncovered the profiles of differentially expressed lncRNAs between normal and cervix carcinoma tissues by using the microarray techniques, and found 1622 upregulated and 3026 downregulated lncRNAs (fold-change>2.0) in cervix carcinoma compared to the normal cervical tissue. Furthermore, we found HOXA11-AS might participate in cervix carcinogenesis by regulating HOXA11, which is involved in regulating biological processes of cervix cancer. This study afforded expression profiles of lncRNAs between cervix carcinoma tissue and normal cervical tissue, which could provide database for further research about the function and mechanism of key-lncRNAs in cervix carcinoma, and might be helpful to explore potential diagnosis factors and therapeutic targets for cervix carcinoma., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

Background/aims: Chemoresistance of breast cancer is a growing problem and still a major clinical obstacle to successful treatment in clinical patients. miR-760 was significantly downregulated in chemoresistance breast cancer tissues compared to chemo-sensitive tissues in our previous study. However, the role of miR-760 in modulating drug resistance remains largely unexplored. In this study, we sought to determine the expression pattern of miR-760 targeted mRNAs, and explore their potential functions and participated-pathways in breast cancer drug resistance cells., Results: Compared to parental cell line MCF-7, miR-760 was downregulated by 6.15 folds in MCF-7/Adr cells. The qRT-PCR result showed that compared to miR-760 negative control cells group, miR-760 was up-regulated 15.817 folds after miR-760 lentiviral transfection in miR-760 mimics group. The microarray data showed that 270 genes were dysregulated over 2-fold change in MCF-7/Adr cells after miR-760 overexpressed, including 241 up-regulated and 29 downregulated genes. GO analysis result appeared that the predicted target genes of miR-760 mainly regulated DNA binding, protein binding, molecular function, nucleic acid binding, and so on; the pathway analysis data demonstrated that these target genes mainly involved in cell cycle, TGF-beta signaling pathway, mRNA processing reactome, G protein signaling, apoptosis, Wnt signaling pathway, and other signaling pathways. There were 3 predicted target genes (RHOB, ANGOTL4, ABCA1) of miR-760 were selected at a P value<0.05 and the fold enrichment was>40., Conclusion: Our study explored the genes expression pattern after miR-760 overexpresssed, and confirmed 3 dominantly dysregulated genes, which could expand the insights into the miR-760 function and molecular mechanisms in drug resistance of breast cancer. This study might afford a comprehensive understanding of miR-760 as prognostic biomarkers during clinical treatment, and we supposed that the miR-760 expression levels in drug resistance carcinoma tissues could be pursued to develop new strategies for targeted therapies in chemoresistant breast cancer patients., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Mammary fat is the main composition of breast, and is the most probable candidate to affect tumor behavior because the fat produces hormones, growth factors and adipokines, a heterogeneous group of signaling molecules. Gene expression profiling and functional characterization of mammary fat in Chinese women has not been reported. Thus, we collected the mammary fat tissues adjacent to breast tumors from 60 subjects, among which 30 subjects had breast cancer and 30 had benign lesions. We isolated and cultured the stromal vascular cell fraction from mammary fat. The expression of genes related to adipose function (including adipogenesis and secretion) was detected at both the tissue and the cellular level. We also studied mammary fat browning. The results indicated that fat tissue close to malignant and benign lesions exhibited distinctive gene expression profiles and functional characteristics. Although the mammary fat of breast tumors atrophied, it secreted tumor growth stimulatory factors. Browning of mammary fat was observed and browning activity of fat close to malignant breast tumors was greater than that close to benign lesions. Understanding the diversity between these two fat depots may possibly help us improve our understanding of breast cancer pathogenesis and find the key to unlock new anticancer therapies.

Background/aims: Breast cancer chemoresistance is a major obstacle to the successful treatment of patients. miRNAs perform critical roles in biological processes, including tumorigenesis and chemoresistance. However, little clinical data are available regarding the relationship between miRNA expression patterns and breast cancer chemoresistance., Methods: We created a doxorubicin-resistant MCF-7 (MCF-/Adr) cell line using a pulse-selection method; then verified the resistance of the MCF-7/Adr cell line to doxorubicin by using the methyl thiazolyl tetrazolium (MTT) assay, terminal deoxyribonucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) staining, and Intracellular doxorubicin accumulation assay. Then, we performed qRT-PCR to detect the expression patterns of 14 selected miRNAs (which are related to breast cancer resistance) in both cell lines. Subsequently, we performed a bioinformatics analysis, including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, to determine the putative functions of 13 differentially expressed miRNA-targeted genes. Finally, we tested the expression levels of these 13 miRNAs in 10 chemotherapy non-responder breast cancer tissues and 29 responder tissues. All statistical analyses were performed by a two-tailed Student's t-test, and a P value less than 0.05 was considered statistically significant., Results: The results of the MTT assay showed that the MCF-7/Adr cell line was significantly more resistant to doxorubicin compared to the MCF-7 cells The results of the TUNEL assay indicated that doxorubicin induced an increase in the number apoptotic cells in the MCF-7 group. Additionally, the accumulation of doxorubicin was higher in MCF-7 cells compared to MCF-7/Adr cells, which was consistent with the MTT and TUNEL results. The qRT-PCR results demonstrated that compared to the parental MCF-7 cell line, miR-200a, miR-141, miR-200c, miR-31, miR-429, and miR-196b were over-expressed, and let-7e, miR-576-3p, miR-125b-1, miR-370, miR-145, miR-765, and miR-760 were significantly down-regulated in MCF-7/Adr cells. The GO analysis results revealed that the predicted target genes of these 14 miRNAs primarily regulated protein binding, zinc ion binding, DNA binding, and transcription factor activity. The KEGG data demonstrated that these target genes are mainly involved in the MAPK signaling pathway, regulation of the actin cytoskeleton, cytokine-cytokine receptor interaction, and other signaling pathways. Compared to the breast cancer tissues from chemotherapy responders, 10 miRNAs were identified to be dysregulated in the chemoresistant breast cancer tissues. Three of these miRNAs were up-regulated (miR-141, miR-200c, and miR-31), and 7 were down-regulated (let-7e, miR-576-3p, miR-125b-1, miR-370, miR-145, miR-765, and miR-760)., Conclusion: In this study, we identified 10 dysregulated miRNAs in both breast cancer cells and chemoresistant tissues, which might be biomarkers for the prognosis of breast cancer chemoresistance. Our study contributes to a comprehensive understanding of prognostic biomarkers during clinical treatment, and we hypothesize that the miRNA signatures of drug-resistant carcinoma tissues could be useful for developing new strategies for targeted therapies in patients with chemoresistant breast cancer., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Several studies have been conducted to examine the association between CD44 expression and the prognosis of gastric cancer (GC). However, the conclusions remain controversial. We conducted a meta-analysis study of 16 published studies with 2403 patients to evaluate the correlation between CD44 expression and clinicopathological characteristics and overall survival of the GC patients. Pooled odds ratios (ORs) and their 95% confidence intervals (CIs) were used to assess the correlation of CD44 expression with the clinicopathological features of GC patients. Hazard ratios (HRs) with their 95% confidence intervals (CIs) were used to assess the association between CD44 and prognosis of GC patients. Total CD44 expression was detected in ten studies, and CD44v5 and CD44v6 expressions were detected in one and five papers, respectively. The results revealed that CD44 expression was associated with some clinicopahological features, such as lymph node metastasis (pooled OR=1.81, 95% CI=1.44-2.34, P=0.000), distant metastasis (pooled OR=3.29, 95% CI=1.90-5.67, P=0.001) and TNM stage (Pooled OR=1.84, 95% CI=1.13-2.99, P=0.014). Moreover, we also found that GC patients with positive CD44 expression had a worse prognosis than the ones with negative CD44 expression (HR=1.93, 95% CI=1.54-2.42, P=0.000). In stratified analysis, the combined HR with CD44 and CD44v6 was 2.20 (95% CI=1.81-2.67) and 1.70 (95% CI=1.00-2.90), respectively. These results suggested that positive CD44 expression could predict a lower overall survival rate and could be an independent dangerous prognostic factor in GC patients., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)