miR-103a-2-5p/miR-30c-1-3p inhibits the progression of prostate cancer resistance to androgen ablation therapy via targeting androgen receptor variant 7

Androgens and androgen receptors are vital factors involved in prostate cancer progression, and androgen ablation therapies are commonly used to treat advanced prostate cancer. However, the acquisition of androgen ablation therapy resistance remains a challenge. Recently, androgen receptor splicing variants lacking the ligand-binding domain have been reported to play a critical role in the acquisition of androgen ablation therapy resistance. In the present study, we revealed that the messenger RNA expression and the protein levels of an androgen receptor variant 7 (AR-V7) were higher in prostate cancer tissue samples and in the AR-positive prostate cancer cell line, VCaP. In contrast, microRNA (miR)-30c-1-3p/miR-103a-2-5p expression was significantly downregulated in tumor tissues and cells. miR-30c-1-3p/miR-103a-2-5p overexpression could inhibit AR-V7 expression, suppress VCaP cell growth, and inhibit AR-V7 downstream factor expression by directly targeting the 3′-untranslated region of AR-V7. Under enzalutamide (Enza) treatment, the effects of AR-V7 overexpression were the opposite of those of miR-103a-2-5p/miR-30c-1-3p overexpression; more importantly, the effects of miR-103a-2-5p/miR-30c-1-3p overexpression could be significantly reversed by AR-V7 overexpression under Enza. In summary, we demonstrated a novel mechanism of the miR-30c-1-3p/miR-103a-2-5p/AR-V7 axis modulating the cell proliferation of AR-positive prostate cancer cells via AR downstream targets. The clinical application of miR-30c-1-3p/miR-103a-2-5p needs further in vivo validation.     

miR-145-5p affects the differentiation of gastric cancer by targeting KLF5 directly

Krüppel-like factor 5 (KLF5) takes part in the pathologic processes of many types of cancer; however, its expression and roles in the biological behavior of gastric cancer remain unknown. TargetScan suggested that miR-145-5p is the predicted effective and conserved microRNA (miRNA) that binds to KLF5 through its 3′-untranslated region (UTR). We investigated the expression of KLF5 and miR-145-5p messenger RNA (mRNA) in gastric cancer and then analyzed its role in the biological behavior of gastric cancer cells. Our results indicated that KLF5 expression was detected by immunohistochemistry in 39.7% of the gastric cancer cases and was increased compared with that of the corresponding noncancerous normal mucosa (0.01 < p < 0.05). The poorly differentiated subtype showed positive KLF5 expression, whereas the differentiated subtype showed negative KLF5 expression (p < 0.05). Dual-luciferase reporter assay suggested KLF5 3′-UTR was the direct target of miR-145-5p. Compared with the differentiated gastric cancer, miR-145-5p was downregulated in undifferentiated gastric cancer (p < 0.05). The downregulation of KLF5 expression and differentiation of MGC-803 and BGC-823 caused by siKLF5 or miR-145-5p mimic transfection. Our results indicated that miR-145-5p/KLF5 3′-UTR affected the differentiation of gastric cancer. miR-145-5p was able to promote gastric cancer differentiation by targeting KLF5 3′-UTR directly. Our data suggest a novel mechanism for cancer differentiation and a new facet to the role of miR-145-5p/KLF5 in gastric cancer.     

Regulation of Expression of Deoxyhypusine Hydroxylase (DOHH), the Enzyme That Catalyzes the Activation of eIF5A,by miR-331-3p and miR-642-5p in Prostate Cancer Cells

The enzyme deoxyhypusine hydroxylase (DOHH) catalyzes the activation of eukaryotic translation initiation factor (eIF5A), a protein essential for cell growth. Using bioinformatic predictions and reporter gene assays, we have identified a 182-nt element within the DOHH 3′-untranslated region (3′-UTR) that contains a number of target sites for miR-331-3p and miR-642-5p. Quantitative RT-PCR studies demonstrated overexpression of DOHH mRNA and underexpression of miR-331-3p and miR-642-5p in several prostate cancer cell lines compared with normal prostate epithelial cells. Transient overexpression of miR-331-3p and/or miR-642-5p in DU145 prostate cancer cells reduced DOHH mRNA and protein expression and inhibited cell proliferation. We observed synergistic growth inhibition with the combination of miR-331-3p and miR-642-5p and mimosine, a pharmacological DOHH inhibitor. Finally, we identified a significant inverse relationship between the expression of miR-331-3p or miR-642-5p and DOHH in a cohort of human prostate cancer tissues. Our results suggest a novel role for miR-331-3p and miR-642-5p in the control of prostate cancer cell growth via the regulation of DOHH expression and eIF5A activity.     

ATRA inhibits the proliferation of DU145 prostate cancer cells through reducing the methylation level of HOXB13 gene

All-trans retinoic acid (ATRA) has been widely investigated for treatments of many cancers including prostate cancer. HOXB13, silenced in androgen receptor-negative (AR(-)) prostate cancer cells, plays a role in AR(-) prostate cancer cell growth arrest. In this study we intended to elucidate the mechanisms that are involved in the proliferation inhibition of AR(-) prostate cancer cells triggered by ATRA. We discovered that ATRA was able to induce the growth arrest and to increase HOXB13 expression in AR(-) prostate cancer cells. Both EZH2 and DNMT3b participated in the repression of HOXB13 expression through an epigenetic mechanism involving DNA and histone methylation modifications. Specifically, EZH2 recruited DNMT3b to HOXB13 promoter to form a repression complex. Moreover, ATRA could upregulate HOXB13 through decreasing EZH2 and DNMT3b expressions and reducing their interactions with the HOXB13 promoter. Concurrently, the methylation level of the HOXB13 promoter was reduced upon the treatment of ATRA. Results from this study implicated a novel effect of ATRA in inhibition of the growth of AR(-) resistant human prostate cancer cells through alteration of HOXB13 expression as a result of epigenetic modifications.     

Forced Expression of miR-143 Represses ERK5/c-Myc and p68/p72 Signaling in Concert with miR-145 in Gut Tumors of Apc(Min) Mice

Recently, miR-143 and miR-145 have been shown to belong to a subset of microRNAs whose expression is controlled by a complex of a tumor suppressor p53 and DEAD-box RNA helicase subunits p68/p72. While accumulating studies have acknowledged that both miRNAs function as tumor suppressors and are similarly regulated, evidence of their coordinated action against tumorigenesis has been poorly presented. Herein, we establish transgenic mice that express miR-143 under the control of the CAG regulatory unit. When crossbred with Apc(Min/+) mice, the development of tumors in the small intestines is significantly attenuated. In the transgenic small intestine tumors, the endogenous miR-145 is also enhanced and the expression of c-Myc and p68/p72, both of which have been reported to be pivotal for gut tumor development, is suppressed, corresponding to the downregulation of ERK5. We demonstrate that the combination of miR-143 and miR-145 inhibits the expression of c-Myc in human colon cancer cells, whereas miR-145 retards that of p72. Moreover, we show the possibilities that miR-145 modulates p72 expression through its 3' untranslated region and that c-Myc downregulation is involved in both p68 suppression and miR-145 induction. These findings suggest that forced expression of miR-143, probably interacting with endogenous miR-145, inhibits ERK5/c-Myc and p68/p72/β-catenin signaling and hampers small intestine tumor development in Apc(Min/+) mice. This unique cascade, in turn, may prevent overproduction of a subset of tumor suppressive miRNAs by repressing their own modulators, p68/p72.     

MiR-17-5p and MKL-1 modulate stem cell characteristics of gastric cancer cells

Effectively targeting cancer stem cells to treat cancer has great therapeutic prospects. However, the effect of microRNA miR-17/MKL-1 on gastric cancer stem cells has not been studied yet. This study preliminarily explored the mechanism of miR-17/MKL-1 in gastric cancer stem cells. Many previous reports have indicated that microRNA and EMT regulated cancer stem cell characteristics, and miR-17 and MKL-1 were involved as a critical gene in migration and invasion in the EMT pathway. Through RT-PCR, Western Blot, flow cytometry, immunofluorescence, sphere formation xenograft tumor assays and drug resistance, the role of miR-17-5p and MKL-1 on promoting stem cell-like properties of gastric cancer were verified in vivo and vitro. Next, MKL-1 targets CD44, EpCAM, and miR -17-5p promoter verified by luciferase assay and ChIP. Besides, the TCGA database analysis found that both miR-17-5p and MKL-1 increased in gastric cancer, and the prognostic survival of the MKL-1 high expression group was reduced. It is found that MKL-1 promotes expression by targeting miR-17, CD44 and EpCAM promoters. Besides, the TCGA database analysis found that both miR-17-5p and MKL-1 increased in gastric cancer, and the prognostic survival of the MKL-1 high expression group was reduced. These findings reveal new regulatory signaling pathways for gastric cancer stem cells, thus it give new insights on potential early diagnosis and/or molecular therapy for gastric cancer.     

Cardiovascular and Cerebrovascular Disease Associated microRNAs Are Dysregulated in Placental Tissues Affected with Gestational Hypertension,Preeclampsia and Intrauterine Growth Restriction

Aims

To demonstrate that pregnancy-related complications are associated with alterations in cardiovascular and cerebrovascular microRNA expression. Gene expression of 32 microRNAs (miR-1-3p, miR-16-5p, miR-17-5p, miR-20a-5p, miR-20b-5p, miR-21-5p, miR-23a-3p, miR-24-3p, miR-26a-5p, miR-29a-3p, miR-33a-5p, miR-92a-3p, miR-100-5p, miR-103a-3p, miR-122-5p, miR-125b-5p, miR-126-3p, miR-130b-3p, miR-133a-3p, miR-143-3p, miR-145-5p, miR-146a-5p, miR-155-5p, miR-181a-5p, miR-195-5p, miR-199a-5p, miR-208a-3p, miR-210-3p, miR-221-3p, miR-342-3p, miR-499a-5p, and miR-574-3p) was assessed in placental tissues, compared between groups (35 gestational hypertension, 80 preeclampsia, 35 intrauterine growth restriction and 20 normal pregnancies) and correlated with the severity of the disease with respect to clinical signs, delivery date, and Doppler ultrasound parameters. Initially, selection and validation of endogenous controls for microRNA expression studies in placental tissues affected by pregnancy-related complications have been carried out.

Results

The expression profile of microRNAs was different between pregnancy-related complications and controls. The up-regulation of miR-499a-5p was a common phenomenon shared between gestational hypertension, preeclampsia, and intrauterine growth restriction. Preeclamptic pregnancies delivering after 34 weeks of gestation and IUGR with abnormal values of flow rate in the umbilical artery demonstrated up-regulation of miR-1-3b. Preeclampsia and IUGR requiring termination of gestation before 34 weeks of gestation were associated with down-regulation of miR-26a-5p, miR-103a-3p and miR-145-5p. On the other hand, some of microRNAs (miR-16-5p, miR-100-5p, miR-122-5p, miR-125b-5p, miR-126-3p, miR-143-3p, miR-195-5p, miR-199a-5p, miR-221-3p, miR-342-3p, and miR-574-3p) were only down-regulated or showed a trend to down-regulation just in intrauterine growth restriction pregnancies requiring the delivery before 34 weeks of gestation.

Conclusion

Epigenetic changes induced by pregnancy-related complications in placental tissue may cause later onset of cardiovascular and cerebrovascular diseases in offspring.     

Dependence of Intracellular and Exosomal microRNAs on Viral E6/E7 Oncogene Expression in HPV-positive Tumor Cells

Specific types of human papillomaviruses (HPVs) cause cervical cancer. Cervical cancers exhibit aberrant cellular microRNA (miRNA) expression patterns. By genome-wide analyses, we investigate whether the intracellular and exosomal miRNA compositions of HPV-positive cancer cells are dependent on endogenous E6/E7 oncogene expression. Deep sequencing studies combined with qRT-PCR analyses show that E6/E7 silencing significantly affects ten of the 52 most abundant intracellular miRNAs in HPV18-positive HeLa cells, downregulating miR-17-5p, miR-186-5p, miR-378a-3p, miR-378f, miR-629-5p and miR-7-5p, and upregulating miR-143-3p, miR-23a-3p, miR-23b-3p and miR-27b-3p. The effects of E6/E7 silencing on miRNA levels are mainly not dependent on p53 and similarly observed in HPV16-positive SiHa cells. The E6/E7-regulated miRNAs are enriched for species involved in the control of cell proliferation, senescence and apoptosis, suggesting that they contribute to the growth of HPV-positive cancer cells. Consistently, we show that sustained E6/E7 expression is required to maintain the intracellular levels of members of the miR-17~92 cluster, which reduce expression of the anti-proliferative p21 gene in HPV-positive cancer cells. In exosomes secreted by HeLa cells, a distinct seven-miRNA-signature was identified among the most abundant miRNAs, with significant downregulation of let-7d-5p, miR-20a-5p, miR-378a-3p, miR-423-3p, miR-7-5p, miR-92a-3p and upregulation of miR-21-5p, upon E6/E7 silencing. Several of the E6/E7-dependent exosomal miRNAs have also been linked to the control of cell proliferation and apoptosis. This study represents the first global analysis of intracellular and exosomal miRNAs and shows that viral oncogene expression affects the abundance of multiple miRNAs likely contributing to the E6/E7-dependent growth of HPV-positive cancer cells.     

MicroRNA-182-5p aggravates ulcerative colitis by inactivating the Wnt/β-catenin signaling pathway through DNMT3A-mediated SMARCA5 methylation

This research focused on novel molecular mechanisms underlying microRNA (miR)-182-5p in ulcerative colitis (UC). Colon tissues were obtained from UC patients, and dextrose sodium sulfate (DSS)-induced mouse and interleukin-1β (IL-1β)-induced Caco-2 cell models were generated. Then, miR-182-5p, SMARCA5, and the Wnt/β-catenin signaling pathway were altered in IL-1β-stimulated Caco-2 cells and DSS-treated mice to assess their function. MiR-182-5p and SMARCA5 were upregulated and DNMT3A, β-catenin, and Cyclin D1 were downregulated in UC patients, IL-1β-stimulated Caco-2 cells, and DSS-treated mice. Mechanistically, miR-182-5p targeted DNMT3A to upregulate SMARCA5, thus blocking the Wnt/β-catenin signaling pathway. Moreover, SMARCA5 silencing or Wnt/β-catenin signaling pathway activation repressed apoptosis and augmented proliferation and epithelial barrier function of IL-1β-stimulated Caco-2 cells. SMARCA5 silencing annulled the impacts of miR-182-5p overexpression on IL-1β-stimulated Caco-2 cells. SMARCA5 silencing or miR-182-5p inhibition ameliorated intestinal barrier dysfunction in DSS-treated mice. Collectively, miR-182-5p aggravates UC by inactivating the Wnt/β-catenin signaling pathway through DNMT3A-mediated SMARCA5 methylation.     

Hsa_circ_0000119 promoted ovarian cancer development via enhancing the methylation of CDH13 by sponging miR-142-5p

Ovarian cancer is the leading cause of gynecological cancer-related death in women, and is difficult to treat. The aim of our study is to explore the role and action mechanism of hsa_circ_0000119 in ovarian cancer, thus to analyze whether the circular RNA is a potential target for the treatment of the disease. In this present study, our data shows that hsa_circ_0000119 and DNA methyltransferase 1 (DNMT1) was increased, while miR-142-5p was decreased in ovarian cancer. Overexpression of hsa_circ_0000119 promoted tumor growth, while silencing of hsa_circ_0000119 resulted in an opposite effects. Decreasing of hsa_circ_0000119 also notably inhibited the proliferation, migration, and invasion of the ovarian cancer cells. Moreover, the data proves that hsa_circ_0000119 negatively regulated miR-142-5p and cadherin 13 (CDH13) expression, but positively regulated DNMT1 expression. miR-142-5p could interact with hsa_circ_0000119 and DNMT1 3′-UTR. Silencing of DNMT1 could reverse the inhibition of hsa_circ_0000119 to miR-142-5p and CDH13 expression. Importantly, higher level of CDH13 promoter methylation existed in the ovarian tumors than that in matched normal tissues. DNA methyltransferase inhibitor could increase the expression of CDH13 in ovarian cancer cells. In addition, our results also prove that increasing of CDH13 or miR-142-5p effectively reversed the inhibition of hsa _circ_0000119 to the cell malignant phenotypes. Overall, our data demonstrate that hsa_circ_0000119 facilitated ovarian cancer development through increasing CDH13 expression via promoting DNMT1 expression by sponging miR-142-5p. Our data demonstrate the potential role of hsa_circ_0000119 in the treatment of ovarian cancer.     

miRNA-877-5p inhibits malignant progression of prostate cancer by directly targeting SSFA2

In this study, we aimed to investigate the role of miR-877-5p in the malignant phenotypes of prostate cancer (PCa) cells and its underlying mechanism. RT-qPCR analysis was performed to examine the expression of miR- 877-5p and sperm-specific antigen 2 (SSFA2) in PCa tissues and cells. Cell counting kit-8 (CCK-8) assay, 5- ethynyl-20-deoxyuridine (EdU) assay, flow cytometry, wound-healing assay, and Transwell invasion assay were performed to determine the functional roles of miR-877-5p in PCa cells. The association of miR-877-5p with SSFA2 was determined by luciferase reporter and RNA pull-down assays. In this study, we found that the expression level of miR-877-5p was decreased in PCa tissues and cells. Functionally, overexpression of miR- 877-5p exerted tumor suppressor properties in PCa cells. Mechanistically, SSFA2 was identified as a target gene of miR-877-5p, while overexpression of SSFA2 could abrogate the anti-tumor effects of miR-877-5p in PCa cells. These findings demonstrated that miR-877-5p/SSFA2 axis functioned as a potential target for PCa treatment.Key words: prostate cancer, miR-877-5p, proliferation, migration, invasion     

miR-425-5p as an exosomal biomarker for metastatic prostate cancer

Prostate cancer-related deaths are mostly caused by metastasis, which indicates the importance of identifying clinical prognostic biomarkers. In this study, we evaluated the expression profile of exosomal microRNAs (miRNAs) derived from metastatic prostate cancer (mPCa) cell lines (LNCaP and PC-3). miRNA signatures in exosomes and cells were evaluated by miRNA microarray analysis. Fourteen miRNAs were identified as candidates for specific noninvasive biomarkers. The expression of five miRNAs was validated using RT-qPCR, which confirmed that miR-205-5p, miR-148a-3p, miR-125b-5p, miR-183-5p, and miR-425-5p were differentially expressed in mPCa exosomes. Bioinformatic analyses showed that miR-425-5p was associated with residual tumor, pathologic T and N stages, and TP53 status in PCa samples. Gene ontology analysis of negatively correlated and predicted targeted genes showed enrichment of genes related to bone development pathways. The LinkedOmics database indicated that the potential target HSPB8 has a significant negative correlation with miR-425-5p. In conclusion, this study identified a panel of exosomal miRNAs with potential value as prognostic biomarkers for prostate cancer.