LINC01133 as ceRNA inhibits gastric cancer progression by sponging miR-106a-3p to regulate APC expression and the Wnt/ß-catenin pathway.

BACKGROUND: Gastric cancer (GC) is a common malignancy and frequent cause of cancer-related death. Long non-coding RNAs (lncRNAs) have emerged as important regulators and tissue-specific biomarkers of multiple cancers, including GC. Recent evidence has indicated that the novel lncRNA LINC01133 plays an important role in cancer progression and metastasis. However, its function and molecular mechanism in GC remain largely unknown. METHODS: LINC01133 expression was detected in 200 GC and matched non-cancerous tissues by quantitative reverse transcription PCR. Gain- and loss-of-function experiments were conducted to investigate the biological functions of LINC01133 both in vitro and in vivo. Insights into the underlying mechanisms of competitive endogenous RNAs (ceRNAs) were determined by bioinformatics analysis, dual-luciferase reporter assays, quantitative PCR arrays, TOPFlash/FOPFlash reporter assay, luciferase assay, and rescue experiments. RESULTS: LINC01133 was downregulated in GC tissues and cell lines, and its low expression positively correlated with GC progression and metastasis. Functionally, LINC01133 depletion promoted cell proliferation, migration, and the epithelial-mesenchymal transition (EMT) in GC cells, whereas LINC01133 overexpression resulted in the opposite effects both in vitro and in vivo. Bioinformatics analysis and luciferase assays revealed that miR-106a-3p was a direct target of LINC01133, which functioned as a ceRNA in regulating GC metastasis. Mechanistic analysis demonstrated that miR-106a-3p specifically targeted the adenomatous polyposis coli (APC) gene, and LINC01133/miR-106a-3p suppressed the EMT and metastasis by inactivating the Wnt/ß-catenin pathway in an APC-dependent manner. CONCLUSIONS: Our findings suggest that reduced expression of LINC01133 is associated with aggressive tumor phenotypes and poor patient outcomes in GC. LINC01133 inhibits GC progression and metastasis by acting as a ceRNA for miR-106a-3p to regulate APC expression and the Wnt/ß-catenin pathway, suggesting that LINC01133 may serve as a potential prognostic biomarker and anti-metastatic therapeutic target for GC.

Predictive Value of LINC01133 for Unfavorable Prognosis was Impacted by Alcohol in Esophageal Squamous Cell Carcinoma.

BACKGROUND/AIMS: Considerable evidence indicates that long noncoding RNAs (lncRNAs) exert importantly regulatory functions during human cancer initiation and progression and are promising biotargets in the flight against cancer. METHODS: In this study, we evaluated the role of the lncRNA LINC01133 in esophageal squamous cell carcinoma (ESCC). LINC01133 expression in ESCC was examined by quantitative real-time PCR. The correlations between LINC01133 expression and clinicopathological variables and survival were examined by the χ2 test, Kaplan-Meier method, log-rank test, and univariate Cox regression analysis. RESULTS: LINC01133 expression levels were frequently lower in ESCC tissues and cell lines than in paired normal tissues and an immortalized esophageal epithelial cell line, respectively. The expression of LINC01133 decreased in a TNM stage- and lifestyle-independent manner. LINC01133 was an independent protective factor and had an anti-tumor effect in the early stage of ESCC development. More importantly, we discovered that drinking status in our cohort impaired the predictive accuracy of LINC01133 for patients with ESCC. Furthermore, a new risk model combining LINC01133 expression, drinking status, and TNM stage provided better survival discrimination compared with three other predictors. CONCLUSIONS: Our data indicate that a loss of LINC01133 expression is a potential poor prognostic biomarker and therapeutic target for ESCC and provide additional prognostic information to improve the outcomes of ESCC patients.

Increased expression of LINC00323 correlates with tumor progression and poor prognosis of gastric cancer.

BACKGROUD/AIMS: LINC00323 is a novel lncRNA which has reported to play an important role in the development and recurrence in several cancers. However, the expression and predictive value of LINC00323 in gastric cancer (GC) remain mysterious. METHODS: LINC00323 expression in GC tissues and adjacent normal tissues was evaluated by quantitative reverse-transcription PCR (qRT-PCR). The relationship between LINC00323 expression and clinicopathological features and patients' survival were analyzed. Univariate and multivariate survival analyses were performed. RESULTS: LINC00323 expression were found to be significantly increased in GC tissues. High expression of LINC00323 exerted a pro-tumor effect in the late stage of GC development. Kaplan-Meier analysis showed that patients with high LINC00323 were associated with poor overall survival (OS) and progression-free survival (PFS). Moreover, the combination of TNM stage and drinking status better identified GC patient outcome than those of TNM stage alone. CONCLUSIONS: Our data showed that LINC00323 overexpression might serve as a novel independent prognostic factor for survival of GC patients, suggesting LINC00323 was a potential biomarker and therapeutic target for GC.

Construction of a competing endogenous RNA network and identification of potential regulatory axes in gastric cancer chemoresistance.

BACKGROUND: Emerging evidence highlights the multifunctional role of noncoding RNAs (ncRNAs) in gastric cancer (GC) chemoresistance. However, the comprehensive expression profile and competing endogenous RNAs (ceRNAs) regulatory network of GC chemoresistance remain unanswered. METHODS: The whole-transcriptome sequencing (RNA sequencing) was performed to comprehensively analyze the differentially expressed (DE) lncRNAs, miRNAs and mRNAs in cisplatin-resistant cells MGC-803/DDP and GC cells MGC-803. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted to investigate the biological functions implicated with the DEncRNAs. Then, the cisplatin-resistant-related ceRNA network and potential regulatory axes were constructed by bioinformatic analysis. RESULTS: We successfully generated cisplatin-resistant GC cell line MGC-803/DDP. Differential expression analysis showed that a total of 1936 DElncRNAs, 2194 DEmRNAs and 174 DEmiRNAs were identified. Functional enrichment analysis indicated that those DEncRNAs were mainly involved in neuroactive ligand-receptor interaction, drug metabolism and Hippo signaling pathway. Subsequently, the cisplatin-resistant-related ceRNA network was constructed with the widely accepted vital chemo-resistant-related genes and signaling pathways. In addition, two constructed regulatory axes (include FAM66C/miR-129-5p/7 mRNAs and SFTA1P/miR-206/FN1 or NRP1) were successfully validated by the Genomic Data Commons (GDC) GC data. CONCLUSIONS: The novel ceRNA network and the potential regulatory axes may provide the most comprehensive view of GC chemoresistance to date. Our findings uncovered potential biomarkers for prognostic prediction and novel therapeutic targets for reversing cisplatin resistance in GC.

Multifunctional Non-Coding RNAs Mediate Latent Infection and Recurrence of Herpes Simplex Viruses.

Herpes simplex viruses (HSVs) often cause latent infection for a lifetime, leading to repeated recurrence. HSVs have been engineered as oncolytic HSVs. The mechanism of the latent infection and recurrence remains largely unknown, which brings great challenges and limitations to eliminate HSVs in clinic and engineer safe oHSVs. Here, we systematically reviewed the latest development of the multi-step complex process of HSV latency and reactivation. Significantly, we first summarized the three HSV latent infection pathways, analyzed the structure and expression of the LAT1 and LAT2 of HSV-1 and HSV-2, proposed the regulation of LAT expression by four pathways, and dissected the function of LAT mediated by five LAT products of miRNAs, sRNAs, lncRNAs, sncRNAs and ORFs. We further analyzed that application of HSV LAT deletion mutants in HSV vaccines and oHSVs. Our review showed that deleting LAT significantly reduced the latency and reactivation of HSV, providing new ideas for the future development of safe and effective HSV therapeutics, vaccines and oHSVs. In addition, we proposed that RNA silencing or RNA interference may play an important role in HSV latency and reactivation, which is worth validating in future.

Cell­cell fusion as an important mechanism of tumor metastasis (Review).

Cell­cell fusion is a dynamic biological phenomenon, which plays an important role in various physiological processes, such as tissue regeneration. Similarly, normal cells, particularly bone marrow­derived cells (BMDCs), may attempt to fuse with cancer cells to rescue them. The rescue may fail, but the fused cells end up gaining the motility traits of BMDCs and become metastatic due to the resulting genomic instability. In fact, cell­cell fusion was demonstrated to occur in vivo in cancer and was revealed to promote tumor metastasis. However, its existence and role may be underestimated, and has not been widely acknowledged. In the present review, the milestones in cell fusion research were highlighted, the evidence for cell­cell fusion in vitro and in vivo in cancer was evaluated, and the current understanding of the molecular mechanisms by which cell­cell fusion occurs was summarized, to emphasize their important role in tumor metastasis. The summary provided in the present review may promote further study into this process and result in novel discoveries of strategies for future treatment of tumor metastasis.

Rab1A promotes cancer metastasis and radioresistance through activating GSK-3ß/Wnt/ß-catenin signaling in nasopharyngeal carcinoma.

Many articles have reported that Rab1A was overexpressed in a variety of human cancers and involved in tumor progression and metastasis. However, the biological function and molecular mechanism of Rab1A in nasopharyngeal carcinoma (NPC) remained unknown until now. Here we found that Rab1A overexpression is a common event and was positively associated with distant metastasis and poor prognosis of NPC patients. Functionally, Rab1A depletion inhibited the migration and EMT phenotype of NPC cells, whereas Rab1A overexpression led to the opposite effect. Furthermore, we reveal an important role for Rab1A protein in the induction of radioresistance via regulating homologous recombination (HR) signaling pathway. Mechanistically, Rab1A activated Wnt/ß-catenin signaling by inhibiting the activity of GSK-3ß via phosphorylation at Ser9. Then Wnt/ß-catenin signaling induced NPC cells radioresistance and metastasis through nuclear translocation of ß-catenin and transcription upregulation of HR pathway-related and EMT-related genes expression. In general, this study shows that Rab1A may serve as a potential biomarker for predicting prognosis in NPC patients. Targeting Rab1A and Wnt/ß-catenin signaling may hold promise to overcome NPC radioresistance.

The Latest Battles Between EGFR Monoclonal Antibodies and Resistant Tumor Cells.

Epidermal growth factor receptor (EGFR) is a tyrosine kinase receptor involved in homeostatic regulation of normal cells and carcinogenesis of epithelial malignancies. With rapid development of the precision medicine era, a series of new therapies targeting EGFR are underway. Four EGFR monoclonal antibody drugs (cetuximab, panitumumab, nimotuzumab, and necitumumab) are already on the market, and a dozen other EGFR monoclonal antibodies are in clinical trials. Here, we comprehensively review the newly identified biological properties and anti-tumor mechanisms of EGFR monoclonal antibodies. We summarize recently completed and ongoing clinical trials of the classic and new EGFR monoclonal antibodies. More importantly, according to our new standard, we re-classify the complex evolving tumor cell resistance mechanisms, including those involving exosomes, non-coding RNA and the tumor microenvironment, against EGFR monoclonal antibodies. Finally, we analyzed the limitations of EGFR monoclonal antibody therapy, and discussed the current strategies overcoming EGFR related drug resistance. This review will help us better understand the latest battles between EGFR monoclonal antibodies and resistant tumor cells, and the future directions to develop anti-tumor EGFR monoclonal antibodies with durable effects.

The impact of Adult Comorbidity Evaluation-27 on the clinical outcome of elderly nasopharyngeal carcinoma patients treated with chemoradiotherapy or radiotherapy: a matched cohort analysis.

Objectives: To evaluate the prognostic significance of Adult Comorbidity Evaluation-27 (ACE-27) for elderly patients (age ≥70 years) with locoregionally advanced nasopharyngeal carcinoma (NPC) treated with Intensity-Modulated Radiotherapy (IMRT), with or without chemotherapy. Methods: 206 elderly patients with locoregionally advanced NPC treated from December 2006 to December 2016 were involved into analysis as the training cohort. Besides, a separate cohort of 72 patients from the same cancer center collected between January 2003 and October 2006 served as the validation cohort. By using propensity score matching (PSM), we created a balanced cohort by matching patients who received chemoradiotherapy with patients who received IMRT alone. Treatment toxicities were calculated between CRT and RT groups using the χ2 test. The primary endpoint was cancer-specific survival (CSS). Multivariate analysis was performed to assess the relative risk for each factor by using a Cox's proportional hazards regression model. Results: The median follow-up was 39.0 months (range = 3-137 months). In the PSM cohort, patients in the CRT group achieved comparable survival compared with patients in the RT group. The 3-year CSS rate was 64.3% and 65.2%, respectively (P =0.764). In multivariate analysis, the addition of chemotherapy to IMRT was not an independent prognostic factor for CSS, whereas a high ACE-27 score was an independent risk factor. In subgroup analysis with ACE-27 score ≥ 2, the 3-year CSS rate was worse in patients from the CRT group (63.5% vs. 46.3%, P = 0.041). Conclusions: CRT is comparable to IMRT alone for elderly patients with locoregionally advanced NPC. The ACE-27 tool may help to identify high-risk subgroup for poor disease outcome and tailor individualized treatment.

Elevated circulating tumor cells and squamous cell carcinoma antigen levels predict poor survival for patients with locally advanced cervical cancer treated with radiotherapy.

OBJECTIVE: To evaluate the prognostic effects of combining serum circulating tumor cells (CTCs) and squamous cell carcinoma antigen (SCC-Ag) levels on patients with locally advanced cervical cancer treated with radiotherapy. METHODS: Ninety-nine patients with locally advanced cervical cancer ([FIGO] stage IIB-IVA) undergoing radiotherapy (RT) or concurrent chemoradiotherapy (CCRT) were identified. The association between serum CTC level and clinicopathological parameters was examined. Univariate and multivariate survival analyses were performed by using Cox's proportional hazards regression model. RESULTS: Elevated CTC and SCC-Ag levels were significantly associated with poor disease-free survival (DFS). Multivariate analysis suggest that serum CTC level, FIGO stage and serum SCC-Ag level were independent prognostic factors for two-year DFS. When CTC and SCC-Ag levels were combined into a new risk model to predict disease progression of cervical cancer patients, it performed a significantly better predictive efficiency compared with either biomarker alone. CONCLUSION: Serum CTC and SCC-Ag levels are potentially useful biomarkers for prediction of prognosis in locally advanced cervical cancer patients and their combination significantly improves predictive ability for survival in locally advanced cervical cancer patients.

RASSF6-mediated inhibition of Mcl-1 through JNK activation improves the anti-tumor effects of sorafenib in renal cell carcinoma.

Ras association domain family member 6 (RASSF6) has been shown to act as a tumor suppressor and predictor of poor prognosis in renal cell carcinoma (RCC). However, little is known about the effects of RASSF6 on sorafenib resistance or the underlying mechanism. Here, we show that RASSF6 expression positively correlates with sorafenib sensitivity in RCC cells and human samples. Stable ectopic overexpression of RASSF6 in RCC cell lines reduces resistance to sorafenib in vitro and in vivo. At a molecular level, RASSF6 activates the JNK signaling pathway, which further contributes to Mcl-1 inhibition. Suppression of the JNK pathway can partially restore Mcl-1 expression and sorafenib resistance. Together, these findings suggest that RASSF6 inhibits sorafenib resistance by repressing Mcl-1 through the JNK-dependent pathway. RASSF6 may serve as a novel regulator for sorafenib therapy in RCC.

Epithelial cell adhesion molecule overexpression regulates epithelial-mesenchymal transition, stemness and metastasis of nasopharyngeal carcinoma cells via the PTEN/AKT/mTOR pathway.

Epithelial cell adhesion molecule (EpCAM) is known to be highly expressed in a variety of epithelial carcinomas, and it is involved in cell adhesion and proliferation. However, its expression profile and biological function in nasopharyngeal carcinoma (NPC) remains unclear. In this study, higher expression of EpCAM was found in NPC samples compared with non-cancer nasopharyngeal mucosa by qRT-PCR. Additionally, immunohistochemistry (IHC) analysis of NPC specimens from 64 cases showed that high EpCAM expression was associated with metastasis and shorter survival. Multivariate survival analysis identified high EpCAM expression as an independent prognostic factor. Ectopic EpCAM expression in NPC cells promoted epithelial-mesenchymal transition (EMT), induced a cancer stem cell (CSC)-like phenotype, and enhanced metastasis in vitro and in vivo without an effect on cell proliferation. Notably, EpCAM overexpression reduced PTEN expression and increased the level of AKT, mTOR, p70S6K and 4EBP1 phosphorylation. Correspondingly, an AKT inhibitor and rapamycin blocked the effect of EpCAM on NPC cell invasion and stem-like phenotypes, and siRNA targeting PTEN rescued the oncogenic activities in EpCAM knockdown NPC cells. Our data demonstrate that EpCAM regulates EMT, stemness and metastasis of NPC cells via the PTEN/AKT/mTOR pathway.

Prognostic impact of pretherapeutic gamma-glutamyltransferase on patients with nasopharyngeal carcinoma.

BACKGROUND: Gamma-glutamyltransferase (GGT) is a membrane-bound enzyme involved in the metabolism of glutathione. Studies suggested that GGT played an important role in the tumor development, progression, invasion and drug resistance and prognosis. The association between GGT and prognosis of patients with nasopharyngeal carcinoma (NPC) was unknown. This study was conducted to investigate the association of pretherapeutic serum level of GGT with clinical-pathological parameters and survival in patients with NPC. METHODS: Two hundred and twenty-two patients with NPC were recruited in this study and were stratified into two GGT risk groups (≤ 34.5 U/L, > 34.5 U/L). The association of pretherapeutic serum GGT levels with clinical-pathological parameters was examined. Univariate and multivariate survival analyses were performed. FINDINGS: The pretherapeutic serum level of GGT was not associated with gender, age, pathology, T stage, N stage, TNM stage, chemotherapy or radiotherapy in patients with NPC. Patients in the high-risk GGT group had a poorer survival than the low-risk GGT group (3-year overall survival, 74.2% vs. 50.2%, P = 0.001; 3-year progression-free survival, 76.4% vs. 47.1%, P < 0.001; 3-year loco-regional relapse-free survival, 76.4% vs. 51.3%, P < 0.001; 3-year distant metastasis-free survival, 89.5% vs. 66.4%, P < 0.001). Multivariate analysis suggested that patients in the high-risk GGT group had 2.117 (95% confidence interval [CI], 1.225 ∼ 3.659, P = 0.007) times the risk of death, 2.836 (95% CI, 1.765 ∼ 4.557, P < 0.001) times the risk of progression, 2.551 (95% CI, 1.573 ∼ 4.138, P < 0.001) times the risk of relapse, and 3.331 (95% CI, 1.676 ∼ 6.622, P < 0.001) times the risk of metastasis compared with those in the low-risk GGT group. CONCLUSION: The pretherapeutic serum level of GGT might serve as a novel independent prognostic factor for overall-survival, progression-free survival, loco-regional relapse-free survival and distant metastasis-free survival in patients with NPC.

Overexpression of Rab1B and MMP9 predicts poor survival and good response to chemotherapy in patients with colorectal cancer.

Rab1B has recently been reported to be involved in human cancer, but the role of Rab1B in colorectal cancer (CRC) remains unclear. In this study, we investigated the expression of Rab1B and MMP9 in CRC by qRT-PCR, immunoblot and immunohistochemistry and analyzed the clinical significance. The results show that Rab1B and MMP9 are increased at both mRNA and protein levels in CRC cell lines and tissues, as measured by qRT-PCR and immunoblotting. The high protein expression of Rab1B and MMP9 in 179 CRC tissues is associated with deep tumor invasion, lymph-node metastasis and advanced TNM stage. Survival analysis indicates that patients with overexpression of Rab1B or MMP9 have significantly worse overall survival and progression-free survival, but better response to chemotherapy than those with low expression of proteins, and that Rab1B is an independent prognostic factor for CRC patients. Furthermore, when Rab1B and MMP9 are combined into a new risk model, it has a remarkably better prediction of prognosis than each protein alone. In conclusion, Rab1B and MMP9 are potential prognostic biomarkers and their combination significantly improves predictive power for survival and chemotherapy response in CRC patients.

BMP2 promotes proliferation and invasion of nasopharyngeal carcinoma cells via mTORC1 pathway.

Bone morphogenetic protein-2 (BMP2) is a secreted protein that highly expressed in a variety of cancers and contributes to cell proliferation, migration, invasiveness, mobility, metastasis and EMT. However, its clinical significance and biological function in nasopharyngeal carcinoma (NPC) remain unknown up to now. Up-regulation of BMP2 was first observed in NPC cell lines by a genome-wide transcriptome analysis in our previous study. In this study, BMP2 mRNA was detected by qRT-PCR and data showed that it was upregulated in NPC compared with non-cancerous nasopharynx samples. Immunohistochemistry (IHC) analysis in NPC specimens revealed that high BMP2 expression was significantly associated with clinical stage, distant metastasis and shorter survival of NPC patients. Moreover, overexpression of BMP2 in NPC cells promoted cell proliferation, migration, invasiveness and epithelial-mesenchymal transition (EMT). Mechanistically, BMP2 overexpression increase phosphorylated protein level of mTOR, S6K and 4EBP1. Correspondingly, mTORC1 inhibitor rapamycin blocked the effect of BMP2 on NPC cell proliferation and invasion. In conclusion, our results suggest that BMP2 overexpression in NPC enhances proliferation, invasion and EMT of tumor cells through the mTORC1 signaling pathway.

Elevated FOXO6 expression correlates with progression and prognosis in gastric cancer.

The FOXO6 correlated with tumor progression in a wide range of carcinomas, yet little is known in gastric cancer. The expression of FOXO6 and matrix metallopeptidase 9 (MMP-9) was assessed by immunohistochemistry in 192 gastric carcinoma specimens. The correlation between FOXO6 expression with MMP-9, clinicopathological/prognostic value in gastric cancer was examined. FOXO6 overexpression was significantly associated with depth of invasion, lymph node metastasis and stage of disease. In univariate and multivariate analyses, FOXO6 was an independent prognostic factor for both overall survival (OS) and recurrence-free survival (RFS). Moreover, FOXO6 over-expression was correlated with poor prognosis in patients subgroups stratified by tumor size, depth of invasion and lymph node metastasis. FOXO6 expression was increased in both prominent serosal invasion group and lymph node metastasis group. In addition, FOXO6 expression was positively correlated with MMP-9 among 192 gastric cancer tissues. Patients with FOXO6 over-expression had poor OS and shorter RFS in low and high invasiveness groups. Furthermore, stratified analysis showed that the TNM stage I patients with high FOXO6 expression had poor prognosis than those with low FOXO6 expression. In conclusion, FOXO6 overexpression promotes tumor aggressiveness and prognosis, and could be a promising target for prognostic prediction in gastric cancer patients. CONDENSED ABSTRACT: The aim of this study was to analyze the role of FOXO6 in patients with gastric carcinoma. FOXO6 may play an important role on tumor invasion, metastasis and prognosis. It may also serve as a novel target for prognostic prediction.

Overexpressed HDAC4 is associated with poor survival and promotes tumor progression in esophageal carcinoma.

Histone deacetylases (HDACs) mediate histone deacetylation, leading to transcriptional repression, which is involved in many diseases, including age-related tissue degeneration, heart failure and cancer. In this study, we were aimed to investigate the expression, clinical significance and biological function of HDAC4 in esophageal carcinoma (EC). We found that HDAC4 mRNA and protein are overexpressed in esophageal squamous cell carcinoma (ESCC) tissues and cell lines. HDAC4 overexpression is associated with higher tumor grade, advanced clinical stage and poor survival. Mechanistically, HDAC4 promotes proliferation and G1/S cell cycle progression in EC cells by inhibiting cyclin-dependent kinase (CDK) inhibitors p21 and p27 and up-regulating CDK2/4 and CDK-dependent Rb phosphorylation. HDAC4 also enhances ESCC cell migration. Furthermore, HDAC4 positively regulates epithelial-mesenchymal transition (EMT) by increasing the expression of Vimentin and decreasing the expression of E-Cadherin/α-Catenin. Together, our study shows that HDAC4 overexpression is important for the oncogenesis of EC, which may serve as a useful prognostic biomarker and therapeutic target for this malignancy.

miR-601 is a prognostic marker and suppresses cell growth and invasion by targeting PTP4A1 in breast cancer.

MicroRNAs (miRNA) play important roles in the initiation and progression of breast cancer. Here, we investigated the role of miR-601 in breast cancer and found that its expression was significantly down-regulated in breast cancer tissues compared with matched adjacent non-cancerous breast tissues. Moreover, we found that down-regulation of miR-601 was closely associated with distant metastasis and poor distant metastasis-free survival in breast cancer. In addition, miR-601 levels were inversely correlated with metastatic potential of human breast cancer cell lines. Further experiments showed that ectopic overexpression of miR-601 suppressed breast cancer cell proliferation, migration and invasion, whereas miR-601 knockdown promoted breast cancer cell proliferation, migration and invasion. Furthermore, protein tyrosine phosphatase type IVA 1 (PTP4A1) was identified as a direct target of miR-601. Overexpression of miR-601 repressed PTP4A1 mRNA and protein expression. Conversely, inhibition of miR-601 increased PTP4A1 mRNA and protein expression. Taken together, our data suggest that miR-601 inhibits growth and invasion of breast cancer cells by targeting PTP4A1 and that miR-601 is a potential biomarker for prognosis and therapeutic target in breast cancer.

MicroRNA-711 is a prognostic factor for poor overall survival and has an oncogenic role in breast cancer.

MicroRNAs are important in cancer development and progression. In the present study, the clinical significance and function of microRNA-711 (miR-711) expression in breast cancer were investigated. The expression level of miR-711 was analyzed in breast cancer tissue samples using reverse transcription-quantitative polymerase chain reaction. Cell proliferation, colony formation, apoptosis and Transwell assays were performed in breast cancer cell lines transfected with miR-711 mimics or inhibitors, or control sequence. miR-711 was found to be upregulated in 30 formalin-fixed paraffin-embedded breast cancer tissue samples compared with paired non-cancerous breast tissues (P<0.05). Furthermore, a higher miR-711 expression was demonstrated to be associated with poor overall and disease-free survival times in 161 breast cancer patients, and miR-711 was identified as an independent prognostic factor using multivariate Cox regression analysis. In vitro, overexpression of miR-711 resulted in a significant increase in proliferation, colony formation, migration and invasion of breast cancer cells. By contrast, downregulating miR-711 inhibited cell proliferation, colony formation, migration and invasion and enhanced the rate of apoptosis of breast cancer cells. To the best of our knowledge, the present study is the first to demonstrate that miR-711 is an independent prognostic factor and serves an important oncogenic function in breast cancer, suggesting that miR-711 is a potential biomarker of prognosis and a molecular therapeutic target in breast cancer.