Insulin-like growth factor-I induces chemoresistence to docetaxel by inhibiting miR-143 in human prostate cancer

Non-Coding RNAs and the Development of Chemoresistance to Docetaxel in Prostate Cancer: Regulatory Interactions and Approaches Based on Machine Learning Methods

Chemotherapy based on taxane-class drugs is the gold standard for treating advanced stages of various oncological diseases. However, despite the favorable response trends, most patients eventually develop resistance to this therapy. Drug resistance is the result of a combination of different events in the tumor cells under the influence of the drug, a comprehensive understanding of which has yet to be determined. In this review, we examine the role of the major classes of non-coding RNAs in the development of chemoresistance in the case of prostate cancer, one of the most common and socially significant types of cancer in men worldwide. We will focus on recent findings from experimental studies regarding the prognostic potential of the identified non-coding RNAs. Additionally, we will explore novel approaches based on machine learning to study these regulatory molecules, including their role in the development of drug resistance.

Targeting of AKT1 by miR-143-3p Suppresses Epithelial-to-Mesenchymal Transition in Prostate Cancer

An altered expression of miR-143-3p has been previously reported in prostate cancer where it is purported to play a tumor suppressor role. Evidence from other cancers suggests miR-143-3p acts as an inhibitor of epithelial-to-mesenchymal transition (EMT), a key biological process required for metastasis. However, in prostate cancer the interaction between miR-143-3p and EMT-associated mechanisms remains unclear. Therefore, this paper investigated the link between miR-143-3p and EMT in prostate cancer using in vitro and in silico analyses. PCR detected that miR-143-3p expression was significantly decreased in prostate cancer cell lines compared to normal prostate cells. Bioinformatic analysis of The Cancer Genome Atlas Prostate Adenocarcinoma (TCGA PRAD) data showed a significant downregulation of miR-143-3p in prostate cancer, correlating with pathological markers of advanced disease. Functional enrichment analysis confirmed the significant association of miR-143-3p and its target genes with EMT. The EMT-linked gene AKT1 was subsequently shown to be a novel target of miR-143-3p in prostate cancer cells. The in vitro manipulation of miR-143-3p levels significantly altered the cell proliferation, clonogenicity, migration and expression of EMT-associated markers. Further TCGA PRAD analysis suggested miR-143-3p tumor expression may be a useful predictor of disease recurrence. In summary, this is the first study to report that miR-143-3p overexpression in prostate cancer may inhibit EMT by targeting AKT1. The findings suggest miR-143-3p could be a useful diagnostic and prognostic biomarker for prostate cancer.

Angiogenesis and prostate cancer: MicroRNAs comes into view

Angiogenesis, the formation of new blood vessels, is an important stage in the growth of cancer. Extracellular matrix, endothelial cells, and soluble substances must be carefully coordinated during the multistep procedure of angiogenesis. Inducers and inhibitors have been found to control pretty much every phase. In addition to benign prostatic hyperplasia, prostatic intraepithelial neoplasia, and angiogenesis have a critical role in the initiation and progression of prostate cancer. MicroRNA (miRNA) is endogenous, short, non-coding RNA molecules of almost 22 nucleotides play a role in regulating cellular processes and regulating several genes' expression. Through controlling endothelial migration, differentiation, death, and cell proliferation, miRNAs have a significant function in angiogenesis. A number of pathological and physiological processes, particularly prostate cancer's emergence, depend on the regulation of angiogenesis. Investigating the functions played with miRNAs in angiogenesis is crucial because it might result in the creation of novel prostate cancer therapies that entail regulating angiogenesis. The function of several miRNAs and its targeting genes engaged in cancer of the prostate angiogenesis will be reviewed in this review in light of the most recent developments. The potential clinical utility of miRNAs potentially a novel therapeutic targets will also be explored, as well as their capacity to control prostate cancer angiogenesis and the underlying mechanisms.

Deregulated microRNAs Involved in Prostate Cancer Aggressiveness and Treatment Resistance Mechanisms

Prostate cancer (PCa) is the most frequently diagnosed cancer and the second leading cause of cancer deaths among American men. Complex genetic and epigenetic mechanisms are involved in the development and progression of PCa. MicroRNAs (miRNAs) are short noncoding RNAs that regulate protein expression at the post-transcriptional level by targeting mRNAs for degradation or inhibiting protein translation. In the past two decades, the field of miRNA research has rapidly expanded, and emerging evidence has revealed miRNA dysfunction to be an important epigenetic mechanism underlying a wide range of diseases, including cancers. This review article focuses on understanding the functional roles and molecular mechanisms of deregulated miRNAs in PCa aggressiveness and drug resistance based on the existing literature. Specifically, the miRNAs differentially expressed (upregulated or downregulated) in PCa vs. normal tissues, advanced vs. low-grade PCa, and treatment-responsive vs. non-responsive PCa are discussed. In particular, the oncogenic and tumor-suppressive miRNAs involved in the regulation of (1) the synthesis of the androgen receptor (AR) and its AR-V7 splice variant, (2) PTEN expression and PTEN-mediated signaling, (3) RNA splicing mechanisms, (4) chemo- and hormone-therapy resistance, and (5) racial disparities in PCa are discussed and summarized. We further provide an overview of the current advances and challenges of miRNA-based biomarkers and therapeutics in clinical practice for PCa diagnosis/prognosis and treatment.

microRNA-497 slows esophageal cancer development and reverses chemotherapy resistance through its target QKI

Esophageal cancer (EC) is considered one of the most lethal cancers in human beings, and multiple miRNAs have been investigated to be involved in EC development by targeting their target genes. However, the function and related mechanism of miRNA-497 on EC tumorigenesis remain uncertain. This study first demonstrated that the expression levels of miR-497 in esophageal cancer specimens and cells were down-regulated. Forced expression of miR-497 inhibited cell proliferation, tube formation and migration in EC cells. To further investigate the potential molecular mechanism of miR-497 suppression in regulating EC, we found that miR-497 directly binds to the 3'-untranslational region of QKI, miR-497 overexpression suppressed QKI expression. We further found that overexpression of miR-497 enhanced the effect of chemotherapy in EC cell lines, and prevented the tumor growth of EC in vivo. Our findings indicated that miR-497 suppression increased QKI expression and therapeutic resistance of esophageal cancer, which is likely to be a biomarker of EC progression and potential therapeutic target.

Inceptor correlates with markers of prostate cancer progression and modulates insulin/IGF1 signaling and cancer cell migration

OBJECTIVE

The insulin/insulin-like growth factor 1 (IGF1) pathway is emerging as a crucial component of prostate cancer progression. Therefore, we investigated the role of the novel insulin/IGF1 signaling modulator inceptor in prostate cancer.

METHODS

We analyzed the expression of inceptor in human samples of benign prostate epithelium and prostate cancer. Further, we performed signaling and functional assays using prostate cancer cell lines.

RESULTS

We found that inceptor was expressed in human benign and malignant prostate tissue and its expression positively correlated with various genes of interest, including genes involved in androgen signaling. In vitro, total levels of inceptor were increased upon androgen deprivation and correlated with high levels of androgen receptor in the nucleus. Inceptor overexpression was associated with increased cell migration, altered IGF1R trafficking and higher IGF1R activation.

CONCLUSIONS

Our in vitro results showed that inceptor expression was associated with androgen status, increased migration, and IGF1R signaling. In human samples, inceptor expression was significantly correlated with markers of prostate cancer progression. Taken together, these data provide a basis for investigation of inceptor in the context of prostate cancer.

Emerging Role of IGF-1 in Prostate Cancer: A Promising Biomarker and Therapeutic Target

Prostate cancer (PCa) is a highly heterogeneous disease driven by gene alterations and microenvironmental influences. Not only enhanced serum IGF-1 but also the activation of IGF-1R and its downstream signaling components has been increasingly recognized to have a vital driving role in the development of PCa. A better understanding of IGF-1/IGF-1R activity and regulation has therefore emerged as an important subject of PCa research. IGF-1/IGF-1R signaling affects diverse biological processes in cancer cells, including promoting survival and renewal, inducing migration and spread, and promoting resistance to radiation and castration. Consequently, inhibitory reagents targeting IGF-1/IGF-1R have been developed to limit cancer development. Multiple agents targeting IGF-1/IGF-1R signaling have shown effects against tumor growth in tumor xenograft models, but further verification of their effectiveness in PCa patients in clinical trials is still needed. Combining androgen deprivation therapy or cytotoxic chemotherapeutics with IGF-1R antagonists based on reliable predictive biomarkers and developing and applying novel agents may provide more desirable outcomes. This review will summarize the contribution of IGF-1 signaling to the development of PCa and highlight the relevance of this signaling axis in potential strategies for cancer therapy.

Docetaxel suppressed cell proliferation through Smad3/HIF-1α-mediated glycolysis in prostate cancer cells

BACKGROUND

Tumor glycolysis is a critical event for tumor progression. Docetaxel is widely used as a first-line drug for chemotherapy and shown to have a survival advantage. However, the role of docetaxel in tumor glycolysis remained poorly understood.

METHODS

The effect of Docetaxel in tumor glycolysis and proliferation were performed by CCK-8, Western blotting, real-time PCR, glucose, and lactate detection and IHC. ChIP and luciferase assay were used to analyze the mechanism of Docetaxel on Smad3-mediated HIF-1α transactivity.

RESULTS

In this study, we showed that docetaxel treatment led to a significant inhibition of cell proliferation in prostate cancer cells through PFKP-mediated glycolysis. Addition of lactate, a production of glycolysis, could reverse the inhibitory effect of docetaxel on cell proliferation. Further analysis has demonstrated that phosphorylation of Smad3 (Ser213) was drastically decreased in response to docetaxel stimulation, leading to reduce Smad3 nuclear translocation. Luciferase and Chromatin immunoprecipitation (ChIP) analysis revealed that docetaxel treatment inhibited the binding of Smad3 to the promoter of the HIF-1α gene, suppressing transcriptional activation of HIF-1α. Moreover, ectopic expression of Smad3 in prostate cancer cells could overcome the decreased HIF-1α expression and its target gene PFKP caused by docetaxel treatment. Most importantly, endogenous Smad3 regulated and interacted with HIF-1α, and this interaction was destroyed in response to docetaxel treatment. What's more, both HIF-1α and PFKP expression were significantly reduced in prostate cancer received docetaxel treatment in vivo.

CONCLUSION

These findings extended the essential role of docetaxel and revealed that docetaxel inhibited cell proliferation by targeting Smad3/HIF-1α signaling-mediated tumor Warburg in prostate cancer cells. Video Abstract.

A review of the biological role of miRNAs in prostate cancer suppression and progression

Prostate cancer (PC) is the third-leading cause of cancer-related deaths worldwide. Although the current treatment strategies are progressing rapidly, PC is still representing a substantial medical problem for affected patients. Several factors are involved in PC initiation, progression, and treatments failure including microRNAs (miRNAs). The miRNAs are endogenous short non-coding RNA sequence negatively regulating target mRNA expression via degradation or translation repression. miRNAs play a pivotal role in PC pathogenesis through its ability to initiate the induction of cancer stem cells (CSCs) and proliferation, as well as sustained cell cycle, evading apoptosis, invasion, angiogenesis, and metastasis. Furthermore, miRNAs regulate major molecular pathways affecting PC such as the androgen receptor (AR) pathway, p53 pathway, PTEN/PI3K/AKT pathway, and Wnt/β-catenin pathway. Furthermore, miRNAs alter PC therapeutic response towards the androgen deprivation therapy (ADT), chemotherapy and radiation therapy (RT). Thus, the understanding and profiling of the altered miRNAs expression in PC could be utilized as a non-invasive biomarker for the early diagnosis as well as for patient sub-grouping with different prognoses for individualized treatment. Accordingly, in the current review, we summarized in updated form the roles of various oncogenic and tumor suppressor (TS) miRNAs in PC, revealing their underlying molecular mechanisms in PC initiation and progression.

High aldehyde dehydrogenase 1 activity is related to radiation resistance due to activation of AKT signaling after insulin stimulation in prostate cancer

The association between type 2 diabetes mellitus and prostate cancer is still under investigation, and the relationship between hyperinsulinemia and prostate cancer stem-like cells (CSCs) is elusive. Here, we investigated the function of insulin/AKT signaling in prostate CSCs. We isolated prostate CSCs as aldehyde dehydrogenase 1-high (ALDH1^high) cells from the human prostate cancer 22Rv1 cell line using an ALDEFLUOR assay and established several ALDH1^high and ALDH1^low clones. ALDH1^high clones showed high ALDH1 expression which is a putative CSC marker; however, they showed heterogeneity regarding tumorigenicity and resistance to radiation and chemotherapy. Interestingly, all ALDH1^high clones showed lower phosphorylated AKT (Ser473) (pAKT) levels than the ALDH1^low clones. PI3K/AKT signaling is a key cell survival pathway and we analyzed radiation resistance under AKT signaling activation by insulin. Insulin increased pAKT levels in ALDH1^high and ALDH1^low cells; the fold increase rate of pAKT was higher in ALDH1^high cells than in ALDH1^low cells. Insulin induced resistance to radiation and chemotherapy in ALDH1^high cells, and the increased levels of pAKT induced by insulin were significantly related to radiation resistance. These results suggest that ALDH1 suppresses baseline pAKT levels, but AKT can be activated by insulin, leading to treatment resistance.

Connecting the Dots Between the Gut-IGF-1-Prostate Axis: A Role of IGF-1 in Prostate Carcinogenesis

Prostate cancer (PCa) is the most common malignancy in men worldwide, thus developing effective prevention strategies remain a critical challenge. Insulin-like growth factor 1 (IGF-1) is produced mainly in the liver by growth hormone signaling and is necessary for normal physical growth. However, several studies have shown an association between increased levels of circulating IGF-1 and the risk of developing solid malignancies, including PCa. Because the IGF-1 receptor is overexpressed in PCa, IGF-1 can accelerate PCa growth by activating phosphoinositide 3-kinase and mitogen-activated protein kinase, or increasing sex hormone sensitivity. Short-chain fatty acids (SCFAs) are beneficial gut microbial metabolites, mainly because of their anti-inflammatory effects. However, we have demonstrated that gut microbiota-derived SCFAs increase the production of IGF-1 in the liver and prostate. This promotes the progression of PCa by the activation of IGF-1 receptor downstream signaling. In addition, the relative abundance of SCFA-producing bacteria, such as Alistipes, are increased in gut microbiomes of patients with high-grade PCa. IGF-1 production is therefore affected by the gut microbiome, dietary habits, and genetic background, and may play a central role in prostate carcinogenesis. The pro-tumor effects of bacteria and diet-derived metabolites might be potentially countered through dietary regimens and supplements. The specific diets or supplements that are effective are unclear. Further research into the "Gut-IGF-1-Prostate Axis" may help discover optimal diets and nutritional supplements that could be implemented for prevention of PCa.

Periprostatic adipose tissue promotes prostate cancer resistance to docetaxel by paracrine IGF-1 upregulation of TUBB2B beta-tubulin isoform

Growing evidence supports the pivotal role played by periprostatic adipose tissue (PPAT) in prostate cancer (PCa) microenvironment. We investigated whether PPAT can affect response to Docetaxel (DCTX) and the mechanisms associated. Conditioned medium was collected from the in vitro differentiated adipocytes isolated from PPAT which was isolated from PCa patients, during radical prostatectomy. Drug efficacy was studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide citotoxicity assay. Culture with CM of human PPAT (AdipoCM) promotes DCTX resistance in two different human prostate cancer cell lines (DU145 and PC3) and upregulated the expression of BCL-xL, BCL-2, and TUBB2B. AG1024, a well-known IGF-1 receptor inhibitor, counteracts the decreased response to DCTX observed in presence of AdipoCM and decreased TUBB2B expression, suggesting that a paracrine secretion of IGF-1 by PPAT affect DCTX response of PCa cell. Collectively, our study showed that factors secreted by PPAT elicits DCTX resistance through antiapoptotic proteins and TUBB2B upregulation in androgen independent PCa cell lines. These findings reveal the potential of novel therapeutic strategies targeting adipocyte-released factors and IGF-1 axis to overcome DCTX resistance in patients with PCa.

The Interplay Between Non-coding RNAs and Insulin-Like Growth Factor Signaling in the Pathogenesis of Neoplasia

The insulin-like growth factors (IGFs) are polypeptides with similar sequences with insulin. These factors regulate cell growth, development, maturation, and aging via different processes including the interplay with MAPK, Akt, and PI3K. IGF signaling participates in the pathogenesis of neoplasia, insulin resistance, diabetes mellitus, polycystic ovarian syndrome, cerebral ischemic injury, fatty liver disease, and several other conditions. Recent investigations have demonstrated the interplay between non-coding RNAs and IGF signaling. This interplay has fundamental roles in the development of the mentioned disorders. We designed the current study to search the available data about the role of IGF-associated non-coding RNAs in the evolution of neoplasia and other conditions. As novel therapeutic strategies have been designed for modification of IGF signaling, identification of the impact of non-coding RNAs in this pathway is necessary for the prediction of response to these modalities.

Mechanisms of docetaxel resistance in prostate cancer: The key role played by miRNAs

One of the main problems with the treatment of metastatic prostate cancer is that, despite an initial positive response, the majority of patients develop resistance and progress. In particular, the resistance to docetaxel, the gold standard therapy for metastatic prostate cancer since 2010, represents one of the main factors responsible for the failure of prostate cancer therapy. According to the present knowledge, different processes contribute to the appearance of docetaxel resistance and non-coding RNA seems to play a relevant role in them. In this review, a comprehensive overview of the miRNA network involved in docetaxel resistance is described, highlighting the pathway/s affected by their activity.

Down-Regulation of miR-7 in Gastric Cancer Is Associated With Elevated LDH-A Expression and Chemoresistance to Cisplatin

MicroRNAs (miRNAs) are dysregulated in the context of many cancer types, making them potentially ideal diagnostic or therapeutic targets in patients in which they are aberrantly expressed. In the present study, we found miR-7 to be downregulated in gastric cancer (GC), and we further determined its expression to be closely linked to GC sensitivity to the chemotherapeutic compound cisplatin. This effect appears to be at least partially attributable to the regulation of LDH-A, which is a miR-7 target gene and expression of LDH-A is negatively correlated with miR-7 expression in primary GC tumor samples. When upregulated, we also determined that miR-7 was able to inhibit the proliferation, colony formation, and glycolysis of GC cells owing to its regulation of LDH-A. Moreover, overexpression of miR-7 render cells more sensitive to cisplatin. Our results thus provide novel evidence that miR-7 is a key mediator of GC growth and chemosensitivity through its regulation of LDH-A, thus potentially highlighting this pathway as a therapeutic target for treating affected patients.

IGF-1 regulates the growth of fibroblasts and extracellular matrix deposition in pelvic organ prolapse

This study was carried out to observe the impact of insulin-like growth factor-1 (IGF-1) on human vaginal fibroblasts (HVFs) in the context of pelvic organ prolapse (POP) and to explore its effects on mitogen-activated protein kinases (MAPK) and nuclear factor-κB (NF-κB) signaling pathways. First, it was found that IGF-1 expression reduced in the vaginal wall tissues derived from POP compared to that in non-POP cases. Then the role of IGF-1 was explored in HVFs and thiazolyl blue tetrazolium bromide (MTT) and flow cytometry were used to detect cell viability and cell apoptosis. Western blot assay and quantitative real-time polymerase chain reaction were used to detect the protein and mRNA expression. The results showed that knockdown of IGF-1 inhibited the cell viability of HVFs, promoted the cell apoptosis of HVFs, and decreased the expression of types I and III collagen in HVFs, which was through inhibiting the expression of IGF-1 receptor and MAPK/NF-κB pathways. However, IGF-1 plasmid had the opposite effects on HVFs. In conclusion, our results showed that IGF-1 could activate MAPK and NF-κB pathways, thereby enhancing collagen metabolism and the growth of vaginal wall fibroblasts then to inhibit POP development.

MiR-27b suppresses epithelial-mesenchymal transition and chemoresistance in lung cancer by targeting Snail1

HEADING AIMS

MicroRNA-27b (miR-27b) has been shown to play a role in the progression of many different forms of cancer, but its specific relevance in the context of non-small cell lung cancer (NSCLC) remains uncertain. As such, this study sought to explore the role of miR-27b in NSCLC and the mechanisms whereby it functions.

MATERIALS AND METHODS

We quantified miR-27b and target gene expression via quantitative real-time PCR (RT-qPCR).We then used functional including proliferation assays, migration assay, flow cytometry, and western blotting to explore the mechanisms whereby miR-27b functions in vitro and in vivo. We additionally confirmed miR-27b target genes via luciferase reporter assay.

KEY FINDINGS

We observed a marked decrease in miR-27b expression in NSCLC patient samples relative to paracancerous control tissues. We further found that altering miR-27b expression levels in vitro affected NSCLC tumor cell migration, proliferation, and ability to undergo epithelial-mesenchymal transition. Through the use of target prediction algorithms we identified Snail to be a miR-27b target protein that was suppressed when this miRNA was highlight expressed. Lastly, we found miR-27b expression to increase NSCLC cell sensitivity to cisplatin through its ability to target Snail.

SIGNIFICANCE

Our results clearly demonstrate that miR-27b can suppress NSCLC tumor development and progression, highlighting this miR-27b/Snail1 axis as putative target for the therapeutic treatment of NSCLC.

Long noncoding RNA IRAIN acts as tumor suppressor via miR-125b in multiple myeloma

Long noncoding RNAs (lncRNAs) are aberrantly expressed in a variety of cancer types. The lncRNA IGF1R antisense imprinted non-protein coding RNA (IRAIN) is associated with various cancer types, yet the role of IRAIN in multiple myeloma (MM) progression remains unclear. In the present study it was identified that IRAIN may act as a tumor suppressor in MM, whilst microRNA (miR)-125b may promote tumorigenesis. Downregulation of IRAIN significantly increased the expression of miR-125b. Furthermore, by using dual-luciferase reporter assays, IRAIN was identified as a target of miR-125b. Knockdown of IRAIN promoted MM cell proliferation in vitro. Thus, expression levels of IRAIN may be used to predict the clinical prognosis of patients with MM and may be a novel therapeutic target for treating MM.

MiR-199a Inhibits Tumor Growth and Attenuates Chemoresistance by Targeting K-RAS via AKT and ERK Signalings

Glioma is the most malignant brain tumors in the world, the function and molecular mechanism of microRNA-199a (miR-199a) in glioma is not fully understood. Our research aims to investigate miR-199a/K-RAS axis in regulation of glioma tumor growth and chemoresistance. The function of miR-199a in glioma was investigated through in vitro and in vivo assays. We found that miR-199a in tumor tissues of glioma patients was significantly downregulated in this study. Kinase suppressor of ras 1 (K-RAS), was indicated as a direct target of miR-199a, as well as expression levels of K-RAS were inversely correlated with expression levels of miR-199a in human glioma specimens. Forced expression of miR-199a suppressed AKT and ERK activation, decreased HIF-1α and VEGF expression, inhibited cell proliferation and cell migration, forced expression of K-RAS restored the inhibitory effect of miR-199a on cell proliferation and cell migration. Moreover, miR-199a renders tumor cells more sensitive to temozolomide (TMZ) via targeting K-RAS. In vivo experiment validated that miR-199a functioned as a tumor suppressor, inhibited tumor growth by targeting K-RAS and suppressed activation of AKT, ERK and HIF-1α expression. Taken together, these findings indicated that miR-199a inhibits tumor growth and chemoresistance by regulating K-RAS, and the miR-199a/K-RAS axis is a potential therapeutic target for clinical intervention in glioma.

Exosomes Derived from miR-143-Overexpressing MSCs Inhibit Cell Migration and Invasion in Human Prostate Cancer by Downregulating TFF3

Exosomes are membrane-enclosed nanovesicles that shuttle active cargoes, such as mRNAs and microRNAs (miRNAs), between different cells. Mesenchymal stem cells (MSCs) are able to migrate to the tumor sites and exert complex functions over tumor progress. We investigated the effect of human bone marrow-derived MSC (BMSC)-derived exosomal miR-143 on prostate cancer. During the co-culture experiments, we disrupted exosome secretion by the inhibitor GW4869 and overexpressed exosomal miR-143 using miR-143 plasmid. miR-143 was involved in the progression of prostate cancer via trefoil factor 3 (TFF3). Moreover, miR-143 was downregulated while TFF3 was upregulated in prostate cancer cells and tissues, and miR-143 was found to specifically inhibit TFF3 expression. Human MSC-derived exosomes enriched miR-143 and transferred miR-143 to prostate cancer cells. Furthermore, elevated miR-143 or exosome-miR-143 or silencing TFF3 inhibited the expression of TFF3, proliferating cell nuclear antigen (PCNA), matrix metalloproteinase (MMP)-2, and MMP-9 and PC3 cell proliferation, migration, invasion, and tumor growth, whereas it promoted apoptosis. In conclusion, hMSC-derived exosomal miR-143 directly and negatively targets TFF3 to suppress prostate cancer.

Suppression of miR-143 contributes to overexpression of IL-6, HIF-1α and NF-κB p65 in Cr(VI)-induced human exposure and tumor growth

Hexavalent chromium [Cr(VI)] is a known occupational and environmental contaminant and carcinogen, but new mechanisms of Cr(VI)-induced carcinogenesis remain to be elucidated. In this study, we found that expression of miR-143 is decreased, whereas that of Interleukin 6 (IL-6) is increased in blood samples of Cr(VI)-exposing workers compared with corresponding unexposed workers. In addition, IL-6 was increased in human bronchial epithelial cells (BEAS-Cr) exposed to Cr(VI) compared with unexposed BEAS-2B cells. To further investigate the mechanisms by which Cr(VI) promotes these changes, we assessed the effects of miR-143 on gene expression and found that miR-143 suppressed expression of IL-6, HIF-1α and NF-κB p65, and that inhibiting miR-143 promoted expression of IL-6, HIF-1α and NF-κB p65. Interestingly, IL-6 regulated expression of HIF-1α, and HIF-1α transcriptionally regulated expression of IL-6. Experiments in animals showed that miR-143 inhibited tumor growth and angiogenesis by regulating IL-6/HIF-1α and downstream signaling pathways in vivo. These outcomes support the hypothesis that the miR-143/IL-6/HIF-1α pathway functions to regulate Cr(VI)-induced carcinogenesis.

MicroRNA-22 Suppresses Breast Cancer Cell Growth and Increases Paclitaxel Sensitivity by Targeting NRAS

In recent study, microRNAs have various important functions in diverse biological processes and progression of cancer. In human breast cancer, microRNA-22 has been reported to be downregulated. However, molecular mechanism of microRNA-22 in breast cancer progression and chemosensitivity has not been well studied. In our study, these results demonstrated that microRNA-22 expression levels were significantly reduced in 40 pairs of human breast cancer tissues when compared to normal tissues. Enforced expression of microRNA-22 inhibited activity of cell proliferation and cell migration in breast cancer cells. Furthermore, microRNA-22 targeted NRAS proto-oncogene, GTPase (NRAS) in breast cancer cells. The expression levels of NRAS in human clinical specimens were higher in breast cancer tissues when compared to normal tissues. Moreover, microRNA-22 sensitized breast cancer cells to paclitaxel by regulation of NRAS. Our results then demonstrated that microRNA-22 functioned as a tumor suppressor microRNA and indicated potential application for the diagnosis and treatment of cancer in the future.

Exploring the MIR143-UPAR Axis for the Inhibition of Human Prostate Cancer Cells In Vitro and In Vivo

MIR143 is pathologically downregulated and may function as a tumor suppressor in prostate cancer. Likewise, the urokinase plasminogen activator receptor (UPAR) is overexpressed in prostate carcinoma, representing a negative prognostic marker and putative therapeutic target gene. In this paper, we establish UPAR as a new direct target of MIR143. Luciferase reporter gene constructs identify one of the two in silico-predicted binding sites as functionally relevant for direct MIR143 binding to the 3′ UTR, and, concomitantly, transfection of MIR143 reduces UPAR protein levels in prostate carcinoma cells in vitro. Inhibitory effects on cell proliferation and colony formation, spheroid growth and integrity, and cell viability are extensively analyzed, and they are compared to direct small interfering RNA (siRNA)-mediated uPAR knockdown or combined microRNA (miRNA)-siRNA treatment. Switching to a therapeutically more relevant in vivo model, we demonstrate tumor-inhibitory effects of MIR143 replacement therapy by systemic treatment of mice bearing subcutaneous PC-3 tumor xenografts with MIR143 formulated in polymeric nanoparticles. This efficient, nanoparticle-mediated delivery of intact MIR143 mediates the marked downregulation of uPAR protein, but not mRNA levels, thus indicating translational inhibition rather than mRNA degradation. In summary, we identify UPAR as a direct target gene of MIR143, and we establish the therapeutic anti-tumor potential of nanoparticle-based MIR143 replacement in prostate cancer.