MicroRNA dynamics, PTEN/PI3K/AKT signaling, and their relationship to breast cancer: prospects for pharmaceuticals and natural product application

BACKGROUND

Globally, Breast Cancer (BC) is the most frequent cancer in women and has a major negative impact on the physical and emotional well-being of its patients as well as one of the most common cancers to be diagnosed. Numerous studies have been published to identify various molecular pathways, including PI3K/AKT/PTEN. Moreover, growing evidence suggests that miRNAs have been found to play a vital role in the growth and carcinogenesis of tumors. Because of their crucial in the development and course of the illness, all other molecular variables, molecular pathways and microRNAs have gained recognition as important therapeutic targets in BC due to growing interest among researchers in utilizing synthetic drugs and natural products to target these signaling pathway with encouraging outcomes in vivo, in vitro and preclinical trials in recent years.

METHODS

We searched PUBMED, Science Direct, google scholar, Embase and Scopus for article published from the inception of each database to May 30, 2024.

RESULTS

We discussed PI3K/PTEN/AKT signaling pathway and microRNA activities with breast cancer cell line. In addition, this review covered a wide range of potential drug and natural products as targeted therapies that are linked to downregulating ER-α expression and activity, inhibiting proliferation, migration, metastasis and angiogenesis, inducing apoptosis, cell cycle arrest and sensitizing breast cancer cells. Many studies have been conducted, but as of right now, there are not enough articles to fully explain the treatment and research of breast cancer.

CONCLUSIONS

We also need more and more studies on breast cancer from a variety of perspectives. Future scientist will find it easier to consider breast cancer treatment after reading this article presentation. So, the review focuses on our understanding of the roles that microRNA and PI3/PTEN/AKT signaling pathways play in regulating BC. Furthermore, we emphasized the potential therapeutic benefits of newly discovered inhibitors and the use of natural compounds in alone or combinations during preclinical trials.

The potential of miR-153 as aggressive prostate cancer biomarker

INTRODUCTION

Prostate cancer (PC) is one of the most frequently diagnosed cancers in males. MiR-153, as a member of the microRNA (miRNA) family, plays an important role in PC. This study aims to explore the expression and possible molecular mechanisms of the miR-153 action.

METHODS

Formalin-fixed paraffin-embedded (FFPE) tissues were collected from prostatectomy specimens of 29 metastatic and 32 initial stage PC patients. Expression levels of miR-153 were measured using real-time reverse transcription polymerase chain reaction (qRT-PCR). 2-ΔΔCT method was used for quantitative gene expression assessment. The candidate target genes for miR-153 were predicted by TargetScan. Mutations in target genes of miR-153 were identified using exome sequencing. Protein-protein interaction (PPI) networks, Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to investigate the potential molecular mechanisms of miR-153 in PC.

RESULTS

MiR-153 was significantly up-regulated in PC tissues compared to non-cancerous tissues. The analysis of correlation between the expression level of miR-153 and clinicopathological factors revealed a statistically significant correlation with the stage of the tumor process according to tumor, node, metastasis (TNM) staging system (p = 0.0256). ROC curve analysis was used to evaluate the predictive ability of miR-153 for metastasis development and it revealed miR-153 as a potential prognostic marker (AUC = 0.85; 95%CI 0.75-0.95; sensitivity = 0.72, specificity = 0.86)). According to logistic regression model the high expression of miR-153 increased the risk of metastasis development (odds ratios = 3.14, 95% CI 1.62-8.49; p-value = 0.006). Whole exome sequencing revealed nonsynonymous somatic mutations in collagen type IV alpha 1 (COL4A1), collagen type IV alpha 3 (COL4A3), forkhead box protein O1 (FOXO1), 2-hydroxyacyl-CoA lyase 1 (HACL1), hypoxia-inducible factor 1-alpha (HIF-1A), and nidogen 2 (NID2) genes. Moreover, KEGG analysis revealed that the extracellular matrix-receptor (ECM-receptor) interaction pathway is mainly involved in PC.

CONCLUSION

MiR-153 is up-regulated in PC tissues and may play an important role in aggressive PC by targeting potential target genes.

A comprehensive review on miR-153: Mechanistic and controversial roles of miR-153 in tumorigenicity of cancer cells

miRNAs play a crucial role in regulating genes involved in cancer progression. Recently, miR-153 has been mainly well-known as a tumor suppressive miRNA modulating genes in proliferation, metastasis, EMT, angiogenesis and drug resistance ability of a variety types of cancer. Mechanistic activity of miR-153 in tumorigenicity has not been fully reviewed. This manuscript presents a comprehensive review on the tumor suppressive activity of miR-153 as well as introducing the controversial role of miR-153 as an oncogenic miRNA in cancer. Furthermore, it summarizes all potential non-coding RNAs such as long non-coding RNAs (LncRNAs), transcribed ultra-conserved regions (T-UCRs) and circular RNAs (CircRNAs) targeting and sponging miR-153. Understanding the critical role of miR-153 in cell growth, metastasis, angiogenesis and drug resistance ability of cancer cells, suggests miR-153 as a potential prognostic biomarker for detecting cancer as well as providing a novel treatment strategy to combat with several types of cancer.

In vivo and in vitro impact of miRNA-153 on the suppression of cell growth apoptosis through mTORC2 signaling pathway in breast cancer

PURPOSE

To investigate the effects and mechanism of miRNA-153 on breast cancer cells in vitro and in vivo.

MATERIAL AND METHODS

The cells and mice were divided into five groups: miRNA-153 mimic, miRNA-153 NC, miRNA-153 inhibitor, miRNA-153 inhibitor-NC, and blank control groups. The real-time PCR and western blot were used to detect the rictor expression regulated by miRNA-153. The western blot was used to explore the expression levels of p-Akt Ser473, p-SGK1 Ser422, and p-FOXO1 Thr24 regulated by miRNA-153. The H&E stain was used to detect the morphology and vitality of tumor cells. Flow cytometry analysis or TUNEL detection was used to evaluate the apoptosis of tumor cells.

RESULTS

MiRNA-153 was significantly reduced in breast cancer cell lines. The real-time PCR and western blot assay suggested that the miRNA-153 downregulation of rictor expression, which was correlated with the antitumor effects both in vitro and in vivo. The western blot assay also showed that the expression levels of p-Akt Ser473, p-SGK1 Ser422, and p-FOXO1 Thr24 were largely reduced in miRNA-153 treated group, which indicated that miRNA-153 inhibited breast cancer growth by regulation of mTORC2 signaling pathway. The H&E stain demonstrated that the morphology and vitality of tumor cells in tumor tissues were influenced in miRNA-153 mimic treated group. The TUNEL detection also showed a great quantity of apoptotic cells in the miRNA-153 mimic group.

CONCLUSIONS

All these results uncovering that the miRNA-153 inhibited breast cancer growth via regulation of mTORC2 signaling pathway, which provided breast cancer treatment a novel direction.

Simultaneous learning of individual microRNA-gene interactions and regulatory comodules

BACKGROUND

MicroRNAs (miRNAs) function in post-transcriptional regulation of gene expression by binding to target messenger RNAs (mRNAs). Because of the key part that miRNAs play, understanding the correct regulatory role of miRNAs in diverse patho-physiological conditions is of great interest. Although it is known that miRNAs act combinatorially to regulate genes, precise identification of miRNA-gene interactions and their specific functional roles in regulatory comodules remains a challenge. We developed THEIA, an effective method for simultaneously predicting miRNA-gene interactions and regulatory comodules, which group functionally related miRNAs and genes via non-negative matrix factorization (NMF).

RESULTS

We apply THEIA to RNA sequencing data from breast invasive carcinoma samples and demonstrate its effectiveness in discovering biologically significant regulatory comodules that are significantly enriched in spatial miRNA clusters, biological pathways, and various cancers.

CONCLUSIONS

THEIA is a theoretically rigorous optimization algorithm that simultaneously predicts the strength and direction (i.e., up-regulation or down-regulation) of the effect of modules of miRNAs on a gene. We posit that if THEIA is capable of recovering known clusters of genes and miRNA, then the clusters found by our method not previously identified by literature are also likely to have biological significance. We believe that these novel regulatory comodules found by our method will be a springboard for further research into the specific functional roles of these new functional ensembles of miRNAs and genes,especially those related to diseases like breast cancer.

Prognostic and clinicopathological significance of MicroRNA-153 in human cancers: A meta-analysis

BACKGROUND

Several studies have explored the prognostic value of MicroRNA-153 (miR-153) in various cancers, but obtained inconsistent results. Thus, we conducted a meta-analysis to assess the prognostic significance of miR-153 for patients with cancer.

METHODS

Eligible studies were identified by searching the online databases Pubmed, Embase, Web of Science, Medline,and the China National Knowledge Infrastructure (CNKI) up to March 2020. Hazard ratios (HRs) with 95% CIs and were calculated to clarify the correlation between miR-153 expression and prognosis of different cancers. Odds ratios (ORs) with 95% CI were selected to appraise the correlation between miR-153 with clinicopathological characteristics of cancer patients.

RESULTS

In total, 933 patients from 11 articles were enrolled in our meta-analysis. The results revealed that low miR-153 expression was significantly correlated with poor overall survival (OS) (HR = 2.45, 95% CI = 1.66-3.63, P < .001), but not with disease-free survival (DFS) (HR = 1.67, 95% CI = 0.45-6.19, P = .442). Subgroup analysis found that low miR-153 expression was associated with worse OS in the reported directly from articles group (HR = 2.67, 95% CI: 1.32-5.37, P = .006), survival curves group (HR = 2.10, 95% CI: 1.56-2.84, P < .001), digestive system tumor (HR = 2.76, 95% CI: 1.73-4.41, P < .001), and breast cancer (HR = 4.01, 95% CI: 1.46-11.04, P = .007).Moreover, cancer patients with low miR-153 expression were prone to poor tumor differentiation(poor vs well+moderate, OR = 2.41, 95% CI = 1.52-3.82, P < .001), earlier lymph node metastasis (present vs absent, OR = 2.19, 95% CI = 1.12-4.25, P = .021) and earlier distant metastasis (present vs absent,OR = 8.24, 95% CI = 2.93-23.21, P < .001), but not associated with age,gender and TNM stage.

CONCLUSIONS

This meta-analysis indicated that low miR-153 expression is associated with poor prognosis. miR-153 may serve as an effective predictive biomarker for tumor prognosis, especially for digestive system tumor and breast cancer.

MicroRNA-153-3p regulates cell proliferation and cisplatin resistance via Nrf-2 in esophageal squamous cell carcinoma

Background

Our recent studies have indicated that miR‐153‐3p is downregulated in the esophageal squamous cell carcinoma (ESCC) cell lines and tissues. Upregulation of miR‐153‐3p was found to inhibit migration and invasion of ESCC cells. However, whether miR‐153‐3p regulates the cisplatin sensitivity in ESCC cells remains unclear. In this study, we explored whether and how miR‐153‐3p regulates the proliferation and confers cisplatin resistance in ESCC by targeting the Nrf‐2 protein.

Methods

Eca109 cell line was transfected with microRNA‐153‐3p mimics or Nrf‐2siRNA and cell proliferation and cisplatin resistance were studied. A dual‐luciferase reporter assay was performed on Eca109 cells cotransfected with the wild‐type/mutant 3′UTR sequences of Nrf‐2 and control or microRNA‐153‐3p mimics. We determined the correlation between microRNA‐153‐3p and Nrf‐2 expression in human ESCC samples and explored the effect of Nrf‐2 in the overall survival rate of ESCC patients.

Results

MiR‐153‐3p significantly suppressed cell proliferation and increased the sensitivity of Eca‐109 cells to cisplatin. MiR‐153‐3p showed a negative correlation with Nrf‐2 in human esophageal carcinoma tissues. MiR‐153‐3p suppressed the expression of Nrf‐2 via binding to its 3′‐UTR region. Furthermore, inhibition of Nrf‐2 also decreased cell proliferation and increased the sensitivity of Eca109 cells to cisplatin. High expression of Nrf‐2 in human ESCC samples was associated with poor overall survival of ESCC patients.

Conclusion

MiR‐153‐3p inhibits cell proliferation and confers cisplatin resistance by downregulating Nrf‐2 expression in Eca‐109 cells. Thus, miR‐153‐3p/Nrf‐2 may play an important role in conferring cisplatin resistance in ESCC. Nrf‐2 appears to be a promising therapeutic target for ESCC.

An update review of deregulated tumor suppressive microRNAs and their contribution in various molecular subtypes of breast cancer

BACKGROUND

Breast cancer (BC) is histologically classified into hormone-receptor+ (ER+, PR + ), human epidermal growth factor receptor-2+ (Her2 + ), and triple-negative breast cancer (TNBC) types. The important contribution of tumor-suppressive (TS) microRNAs (miRs) in BC development and treatment have been well-acknowledged in the literature.

OBJECTIVE

The present review focused on the contribution of recently examined TS miRs in the progression and treatment of various histological subtypes of BC.

RESULTS

In summary, various miRs have tumor-suppressive roles in BC, so that their aberrant expression leads to the abnormality in the cellular processes such as enhanced cell growth, decreased apoptosis, cell migration and metastasis, and decreased sensitivity to chemotherapy through deregulated expression of oncogene targets of TS miRs.

CONCLUSION

TS miRs could be regarded as a proper molecular target for target therapy of BC. However, further in vitro and in vivo investigations are required to confirm the exact molecular functions of TS miRs in BC cells to offer more efficient targeted therapies.

MicroRNA-153 inhibits cell proliferation, migration, invasion and epithelial-mesenchymal transition in breast cancer via direct targeting of RUNX2

A number of microRNAs (miRNAs) are involved in the development and malignant progression of numerous types of human cancer including breast cancer. The underlying regulatory mechanism of miRNA-153 (miR-153) in breast cancer progression remains largely unknown. The present study demonstrated that miR-153 expression levels were significantly reduced in breast cancer tissue samples and cell lines, compared with adjacent healthy tissue samples and normal human breast cell line MCF-10A. In addition, low miR-153 expression was associated with advanced clinical staging and metastasis in patients with breast cancer. However, no association with age, subtype or differentiation was identified. Furthermore, patients with breast cancer with low miR-153 expression had poor prognosis, compared with patients with breast cancer with high miR-153 expression. Overexpression of miR-153 reduced proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) in breast cancer SK-BR-3 and BT-549 cells. Runt-related transcription factor 2 (RUNX2), which was revealed to be significantly upregulated in breast cancer, was verified as a target gene of miR-153 in SK-BR-3 and BT-549 cells by luciferase reporter gene assay. High RUNX2 expression was associated with advanced clinical staging as well as distant and lymph node metastasis in patients with breast cancer. However, no association with age, subtype or differentiation was identified. Additionally, an inverse correlation between miR-153 and RUNX2 mRNA expression levels was observed in breast cancer tissues. RUNX2 overexpression reduced the suppressive effects of miR-153 on the proliferation, migration, invasion and EMT of SK-BR-3 and BT-549 cells. The present study indicated that miR-153 may serve a role in breast tumor growth and metastasis via direct targeting of RUNX2. The miR-153/RUNX2 axis may be used as a potential therapeutic target in breast cancer treatment.

MicroRNA-153 affects nasopharyngeal cancer cell viability by targeting TGF-β2

The aim of the present study was to determine the function of microRNA-153 (miR-153) in the viability of nasopharyngeal cancer (NPC) cells and determine the underlying molecular mechanism. The expression of miR-153 in patients with NPC was markedly decreased compared with that in paracarcinoma tissue. miR-153 upregulation observably decreased cell viability, induced apoptosis, increased caspase-3 and -9 activity, and increased the B-cell lymphoma 2 (Bcl-2)-associated X protein/Bcl-2 protein expression ratio in 13-9B cells. miR-153 upregulation also suppressed transforming growth factor-β₂ (TGF-β₂) and Smad2 protein expression in 13-9B cells. TGF-β₂ inhibitor enhanced the effect of miR-153 upregulation on the inhibition of cell viability, induction of apoptosis, increase in caspase-3 and -9 activity, and increase in Bax/Bcl-2 protein expression ratio in 13-9B cells. The results of the present study indicate that miR-153 affects the progression of NPC by targeting the TGF-β₂/Smad2 signaling pathway.

KCNQ1OT1 promotes melanoma growth and metastasis

Melanoma is the deadliest cutaneous neoplasm. To prevent metastasis, early diagnosis and surgical treatment is vital. Long non-coding RNAs (lncRNAs) may serve as biomarkers and therapeutic targets in tumors. We investigated the molecular mechanisms of lncRNA KCNQ1OT1 in melanoma. Real time PCR demonstrated that KCNQ1OT1 expression is up-regulated in melanoma tissues and cells. KCNQ1OT1 promoted cell proliferation and metastasis in melanoma. By directly bindin to miR-153, KCNQ1OT1 acted as a competing endogenous RNA (ceRNA) to de-repress MET expression. Our results may provide the basis for a novel strategy for early detection and/or treatment of melanoma.

In-Silico Integration Approach to Identify a Key miRNA Regulating a Gene Network in Aggressive Prostate Cancer

Like other cancer diseases, prostate cancer (PC) is caused by the accumulation of genetic alterations in the cells that drives malignant growth. These alterations are revealed by gene profiling and copy number alteration (CNA) analysis. Moreover, recent evidence suggests that also microRNAs have an important role in PC development. Despite efforts to profile PC, the alterations (gene, CNA, and miRNA) and biological processes that correlate with disease development and progression remain partially elusive. Many gene signatures proposed as diagnostic or prognostic tools in cancer poorly overlap. The identification of co-expressed genes, that are functionally related, can identify a core network of genes associated with PC with a better reproducibility. By combining different approaches, including the integration of mRNA expression profiles, CNAs, and miRNA expression levels, we identified a gene signature of four genes overlapping with other published gene signatures and able to distinguish, in silico, high Gleason-scored PC from normal human tissue, which was further enriched to 19 genes by gene co-expression analysis. From the analysis of miRNAs possibly regulating this network, we found that hsa-miR-153 was highly connected to the genes in the network. Our results identify a four-gene signature with diagnostic and prognostic value in PC and suggest an interesting gene network that could play a key regulatory role in PC development and progression. Furthermore, hsa-miR-153, controlling this network, could be a potential biomarker for theranostics in high Gleason-scored PC.

miRNAs and their role in the correlation between schizophrenia and cancer (Review)

Schizophrenia (SZ) and cancer (Ca) have a broad spectrum of clinical phenotypes and a complex biological background, implicating a large number of genetic and epigenetic factors. SZ is a chronic neurodevelopmental disorder signified by an increase in the expression of apoptotic molecular signals, whereas Ca is conversely characterized by an increase in appropriate molecular signaling that stimulates uncontrolled cell proliferation. The rather low risk of developing Ca in patients suffering from SZ is a hypothesis that is still under debate. Recent evidence has indicated that microRNAs (miRNAs or miRs), a large group of small non-coding oligonoucleotides, may play a significant role in the development of Ca and major psychiatric disorders, such as SZ, bipolar disorder, autism spectrum disorders, suicidality and depression, through their interference with the expression of multiple genes. For instance, the possible role of let-7, miR-98 and miR-183 as biomarkers for Ca and SZ was investigated in our previous research studies. Therefore, further investigations on the expression profiles of these regulatory, small RNA molecules and the molecular pathways through which they exert their control may provide a plausible explanation as to whether there is a correlation between psychiatric disorders and low risk of developing Ca.

The Ia-2β intronic miRNA, miR-153, is a negative regulator of insulin and dopamine secretion through its effect on the Cacna1c gene in mice

AIMS/HYPOTHESIS

miR-153 is an intronic miRNA embedded in the genes that encode IA-2 (also known as PTPRN) and IA-2β (also known as PTPRN2). Islet antigen (IA)-2 and IA-2β are major autoantigens in type 1 diabetes and are important transmembrane proteins in dense core and synaptic vesicles. miR-153 and its host genes are co-regulated in pancreas and brain. The present experiments were initiated to decipher the regulatory network between miR-153 and its host gene Ia-2β (also known as Ptprn2).

METHODS

Insulin secretion was determined by ELISA. Identification of miRNA targets was assessed using luciferase assays and by quantitative real-time PCR and western blots in vitro and in vivo. Target protector was also employed to evaluate miRNA target function.

RESULTS

Functional studies revealed that miR-153 mimic suppresses both glucose- and potassium-induced insulin secretion (GSIS and PSIS, respectively), whereas miR-153 inhibitor enhances both GSIS and PSIS. A similar effect on dopamine secretion also was observed. Using miRNA target prediction software, we found that miR-153 is predicted to target the 3'UTR region of the calcium channel gene, Cacna1c. Further studies confirmed that Cacna1c mRNA and protein are downregulated by miR-153 mimics and upregulated by miR-153 inhibitors in insulin-secreting freshly isolated mouse islets, in the insulin-secreting mouse cell line MIN6 and in the dopamine-secreting cell line PC12.

CONCLUSIONS/INTERPRETATION

miR-153 is a negative regulator of both insulin and dopamine secretion through its effect on Cacna1c expression, which suggests that IA-2β and miR-153 have opposite functional effects on the secretory pathway.

Identification of miR-10b, miR-26a, miR-146a and miR-153 as potential triple-negative breast cancer biomarkers

Background

Familial triple-negative breast cancers are often linked to mutations in the BRCA1 tumor suppressor gene. In sporadic triple-negative breast cancers BRCA1 is frequently inactivated at the transcriptional level, and it has been reported that this inactivation may be brought about by promoter methylation. More recently, it was found that BRCA1 may also be regulated at the post-transcriptional level by miRNAs. Here, we explored the expression of putative BRCA1-regulating miRNAs in sporadic human triple-negative breast cancer cells.

Methods

Nine sporadic human breast cancer-derived cell lines and one benign breast epithelium-derived cell line were assessed for their hormone receptor, growth factor receptor and cytokeratin status by immunocytochemistry. The expression of 5 selected miRNAs predicted to target BRCA1 was assessed using qRT-PCR in the 10 cell lines. In addition, expression profiles of 84 known breast cancer-associated miRNAs were established in these 10 cell lines using PCR Array and qRT-PCR, respectively. The putative role of pre-selected candidate miRNAs in breast cancer development was assessed through exogenous expression of these miRNAs and their anti-miRNAs (‘antagomirs’) in MDA-MB-231 and MCF7 breast cancer-derived cells.

Results

Based on our expression profiling results, four candidate miRNAs (miR-10b, miR-26a, miR-146a and miR-153) were selected as being potentially involved in triple-negative breast cancer development. Exogenous expression assays revealed that miR-10b and miR-26a, but not miR-146a, can down-regulate the expression of BRCA1 in both triple-negative MDA-MB-231 and luminal epithelial MCF7 breast cancer-derived cells, whereas miR-153 could down-regulate BRCA1 expression only in MCF7 cells. In silico analysis of The Cancer Genome Atlas (TCGA) data confirmed that miR-146a is significantly higher expressed in triple-negative breast tumors compared to other (non triple-negative) breast tumors.

Conclusion

Our work provides evidence for the involvement of specific miRNAs in triple-negative breast cancer development through regulating BRCA1 expression.

Electronic supplementary material

The online version of this article (doi:10.1007/s13402-015-0239-3) contains supplementary material, which is available to authorized users.

MicroRNA-153 is a prognostic marker and inhibits cell migration and invasion by targeting SNAI1 in human pancreatic ductal adenocarcinoma

Human pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer type with early metastasis, which leads to poor prognosis for patients. Mounting evidence suggests that microRNAs (miRNAs) act as critical factors for tumor recurrence and metastasis. miR-153 has been suggested as a novel tumor-associated miRNA, which is involved in tumor metastasis. However, the clinical significance of miR-153 and its role in PDAC remains to be investigated. The aim of the present study was to investigate the expression levels of miR-153 using RT-qPCR in human PDAC cell lines and tissues. A clinical association analysis was performed to investigate the clinical significance of miR-153. The results showed that, the relative expression of miR-153 in PDAC cells was obviously decreased as compared to that in the normal human pancreatic duct epithelial cell line. The mean expression of miR-153 in PDAC tissues was significantly reduced as compared to that in the normal pancreatic tissues. The clinical analysis revealed that a low expression of miR-153 was closely associated with poor prognostic features and shorter long-term survival of PDAC patients. Furthermore, univariate and multivariate Cox regression analyses showed that miR-153 was an independent prognostic factor for predicting survival in PDAC patients. In vitro studies demonstrated that the upregulation of miR-153 inhibited migration and invasion in MIAPaCa-2 cells. By contrast, the downregulation of miR-153 increased the number of migrated and invaded AsPC-1 cells. miR-153 inversely regulated SNAI1 abundance in MIAPaCa-2 cells. Notably, SNAI1 was identified as a direct target of miR-153 in PDAC. Furthermore, an inverse correlation between miR-153 and SNAI1 expression was observed in PDAC tissues. In conclusion, the results showed miR-153 is an independent prognostic marker for predicting survival in PDAC patients and inhibits cell migration and invasion by targeting SNAI1.

Down-regulation of miRNA-452 is associated with adriamycin-resistance in breast cancer cells

Adriamycin (ADR) is an important chemotherapeutic agent frequently used in treatment of breast cancer. However, resistance to ADR results in treatment failure in many patients. Recent studies have indicated that microRNAs (miRNAs) may play an important role in such drug-resistance. In the present study, microRNA-452 (miR-452) was found to be significantly down-regulated in adriamycin-resistant MCF-7 cells (MCF-7/ADR) compared with the parental MCF-7 cells by miRNA microarray and real-time quantitative PCR (RT-qPCR). MiR-452 mimics and inhibitors partially changed the adriamycin-resistance of breast cancer cells, as also confirmed by apoptosis assay. In exploring the potential mechanisms of miR-452 in the adriamycin-resistance of breast cancer cells, bioinformatics analysis, RT-qPCR and Western blotting showed that dysregulation of miR-452 played an important role in the acquired adriamycin-resistance of breast cancer, maybe at least in part via targeting insulin-like growth factor-1 receptor (IGF-1R).

MicroRNA-153 inhibits osteosarcoma cells proliferation and invasion by targeting TGF-β2

Increasing evidence indicates that microRNAs (miRNAs), a class of small noncoding RNAs, participate in almost every step of cellular processes. MiRNAs are aberrantly expressed in human cancers and contribute to cancer development and progression. Study of miRNAs may provide a new clue for understanding the mechanism of carcinogenesis and a new tool for cancer treatment. In the present study, miR-153 was downregulated in human osteosarcoma tissues and cell lines. Introduction of miR-153 mimics into the MG-63 cells inhibited cell proliferation and invasion. Our results further revealed that transforming growth factor beta 2 (TGF-β2) was negatively regulated by miR-153. Furthermore, overexpression of miR-153 decreased p-SMAD2, p-SMAD3, epidermal growth factor receptor (EGFR) and insulin-like growth factor binding protein-3 (IGFBP-3) expressions, which were the downstream signaling molecules of TGF-β. Furthermore, miRNA-153 suppressed TGF-β-mediated MG-63 proliferation and migration. Therefore, our results suggest that miR-153 may act as a tumor suppressor in osteosarcoma through targeting TGF-β2.

Towards a molecular basis of oligometastatic disease: potential role of micro-RNAs

Oligometastasis is a cancer disease state characterized by a limited number of metastatic tumors involving single or few organs and with biological properties that make them potentially amenable to locoregional antitumor therapy. Current clinical data show that they are potentially curable with surgical resection or/and radiotherapy. Yet, mechanisms of progression from primary tumor to oligometastasis, rather than to polymetastases, is lacking in detail. In the current review we focus on the role of micro-RNAs in the regulation of metastases development and the role they may play in the differentiation of oligometastatic from polymetastatic progression. We also discuss the analyses of metastatic samples from oligo-and polymetastatic patients, which suggest that oligometastasis is a distinct biologic entity regulated in part by micro-RNAs. In addition, a review of the known functions of oligometastatic-specific micro-RNAs suggest that they regulate multiple steps in the metastatic cascade, including epithelial–mesenchymal transition, tumor invasion, intravasation, distant vascular extravasation and proliferation in a distant organ. Understanding the role of micro-RNAs and their target genes in oligometastatic disease may allow for the development of targeted therapies to effectively conrol the spread of metastases.