miR-135a leads to cervical cancer cell transformation through regulation of β-catenin via a SIAH1-dependent ubiquitin proteosomal pathway

MiRNA in cervical cancer: Diagnosis to therapy: Systematic review

Cancers are one of the most public health problems worldwide. Among them, cervical cancer (CC) is the fourth most prevalent cancer with 604 000 new cases and 342 000 deaths. Mostly, it is associated with Human papillomavirus (HPV). It has been caused by the aggregation of genetic and epigenetic modifications in cervical epithelial cells. Although genetic mutations are given great attention for the carcinogenesis of CC, epigenetic changes have emerged as a hotspot area for CC biomarkers research with great implications for early diagnosis, prognosis, and treatment response prediction of the disease. Recently, there are several studies focused on miRNAs as biomarkers of cervical cancer. However, the precise function of miRNAs in the development of cervical cancer is not still completely understood, particularly when it comes to unconventional sampling materials like cervical mucus and plasma serum. Hence, this review article will give a summary of the miRNAs profiles that emerge at different stages of cervical cancer progression and their downstream effects on target genes and associated signaling pathways. Finally, these results may provide insight into the use of miRNAs as biomarkers for the prediction or diagnosis of cervical cancer or the development of miRNA-based therapeutics against cervical cancer.

Non-coding RNAs in gynecologic cancer

The term "gynecologic cancer" pertains to neoplasms impacting the reproductive tissues and organs of women encompassing the endometrium, vagina, cervix, uterus, vulva, and ovaries. The progression of gynecologic cancer is linked to various molecular mechanisms. Historically, cancer research primarily focused on protein-coding genes. However, recent years have unveiled the involvement of non-coding RNAs (ncRNAs), including microRNAs, long non-coding RNAs (LncRNAs), and circular RNAs, in modulating cellular functions within gynecological cancer. Substantial evidence suggests that ncRNAs may wield a dual role in gynecological cancer, acting as either oncogenic or tumor-suppressive agents. Numerous clinical trials are presently investigating the roles of ncRNAs as biomarkers and therapeutic agents. These endeavors may introduce a fresh perspective on the diagnosis and treatment of gynecological cancer. In this overview, we highlight some of the ncRNAs associated with gynecological cancers.

Neural crest cells and fetal alcohol spectrum disorders: Mechanisms and potential targets for prevention

Fetal alcohol spectrum disorders (FASD) are a group of preventable and nongenetic birth defects caused by prenatal alcohol exposure that can result in a range of cognitive, behavioral, emotional, and functioning deficits, as well as craniofacial dysmorphology and other congenital defects. During embryonic development, neural crest cells (NCCs) play a critical role in giving rise to many cell types in the developing embryos, including those in the peripheral nervous system and craniofacial structures. Ethanol exposure during this critical period can have detrimental effects on NCC induction, migration, differentiation, and survival, leading to a broad range of structural and functional abnormalities observed in individuals with FASD. This review article provides an overview of the current knowledge on the detrimental effects of ethanol on NCC induction, migration, differentiation, and survival. The article also examines the molecular mechanisms involved in ethanol-induced NCC dysfunction, such as oxidative stress, altered gene expression, apoptosis, epigenetic modifications, and other signaling pathways. Furthermore, the review highlights potential therapeutic strategies for preventing or mitigating the detrimental effects of ethanol on NCCs and reducing the risk of FASD. Overall, this article offers a comprehensive overview of the current understanding of the impact of ethanol on NCCs and its role in FASD, shedding light on potential avenues for future research and intervention.

Cathepsin K promotes the proliferation of hepatocellular carcinoma cells through induction of SIAH1 ubiquitination and degradation

Seven in absentia homolog 1 (SIAH1) was reported to be downregulated in hepatocellular carcinoma (HCC) and played an important role in HCC progression; however, the underlying reason remains unknown. Here, we found that Cathepsin K (CTSK), a protein potentially interacting with SIAH1, inhibits SIAH1 protein level. CTSK was highly expressed in HCC tissues. CTSK inhibition or downregulation suppressed HCC cell proliferation, whereas CTSK overexpression had the opposite effect; it promotes HCC cell proliferation by regulating the SIAH1/protein kinase B (AKT) pathway, wherein promotes SIAH1 ubiquitination. Neural precursor cells expressing developmentally downregulated 4 (NEDD4) was found to be a potential upstream ubiquitin ligase of SIAH1. Further, CTSK could mediate SIAH1 ubiquitination and degradation by increasing SIAH1 autoubiquitination and recruiting NEDD4 to ubiquitinate SIAH1. Finally, the roles of CTSK were confirmed in a xenograft mouse model. In conclusion, oncogenic CTSK was upregulated in human HCC tissues and accelerated HCC cell proliferation by downregulating SIAH1.

miRNAs role in cervical cancer pathogenesis and targeted therapy: Signaling pathways interplay

Cervical cancer (CC) is the primary cause of cancer deaths in underdeveloped countries. The persistence of infection with high-risk human papillomavirus (HPV) is a significant contributor to the development of CC. However, few women with morphologic HPV infection develop invasive illnesses, suggesting other mechanisms contribute to cervical carcinogenesis. MicroRNAs (miRNAs, miRs) are small chain nucleic acids that can regulate wide networks of cellular events. They can inhibit or degrade their target protein-encoding genes. They had the power to regulate CC's invasion, pathophysiology, angiogenesis, apoptosis, proliferation, and cell cycle phases. Further research is required, even though novel methods have been developed for employing miRNAs in the diagnosis, and treatment of CC. We'll go through some of the new findings about miRNAs and their function in CC below. The function of miRNAs in the development of CC and its treatment is one of these. Clinical uses of miRNAs in the analysis, prediction, and management of CC are also covered.

Functional Screen for microRNAs Suppressing Anchorage-Independent Growth in Human Cervical Cancer Cells

The progression of anchorage-dependent epithelial cells to anchorage-independent growth represents a critical hallmark of malignant transformation. Using an in vitro model of human papillomavirus (HPV)-induced transformation, we previously showed that acquisition of anchorage-independent growth is associated with marked (epi)genetic changes, including altered expression of microRNAs. However, the laborious nature of the conventional growth method in soft agar to measure this phenotype hampers a high-throughput analysis. We developed alternative functional screening methods using 96- and 384-well ultra-low attachment plates to systematically investigate microRNAs regulating anchorage-independent growth. SiHa cervical cancer cells were transfected with a microRNA mimic library (n = 2019) and evaluated for cell viability. We identified 84 microRNAs that consistently suppressed growth in three independent experiments. Further validation in three cell lines and comparison of growth in adherent and ultra-low attachment plates yielded 40 microRNAs that specifically reduced anchorage-independent growth. In conclusion, ultra-low attachment plates are a promising alternative for soft-agar assays to study anchorage-independent growth and are suitable for high-throughput functional screening. Anchorage independence suppressing microRNAs identified through our screen were successfully validated in three cell lines. These microRNAs may provide specific biomarkers for detecting and treating HPV-induced precancerous lesions progressing to invasive cancer, the most critical stage during cervical cancer development.

Leveraging Methylation Alterations to Discover Potential Causal Genes Associated With the Survival Risk of Cervical Cancer in TCGA Through a Two-Stage Inference Approach

BACKGROUND

Multiple genes were previously identified to be associated with cervical cancer; however, the genetic architecture of cervical cancer remains unknown and many potential causal genes are yet to be discovered.

METHODS

To explore potential causal genes related to cervical cancer, a two-stage causal inference approach was proposed within the framework of Mendelian randomization, where the gene expression was treated as exposure, with methylations located within the promoter regions of genes serving as instrumental variables. Five prediction models were first utilized to characterize the relationship between the expression and methylations for each gene; then, the methylation-regulated gene expression (MReX) was obtained and the association was evaluated via Cox mixed-effect model based on MReX. We further implemented the aggregated Cauchy association test (ACAT) combination to take advantage of respective strengths of these prediction models while accounting for dependency among the p-values.

RESULTS

A total of 14 potential causal genes were discovered to be associated with the survival risk of cervical cancer in TCGA when the five prediction models were separately employed. The total number of potential causal genes was brought to 23 when conducting ACAT. Some of the newly discovered genes may be novel (e.g., YJEFN3, SPATA5L1, IMMP1L, C5orf55, PPIP5K2, ZNF330, CRYZL1, PPM1A, ESCO2, ZNF605, ZNF225, ZNF266, FICD, and OSTC). Functional analyses showed that these genes were enriched in tumor-associated pathways. Additionally, four genes (i.e., COL6A1, SYDE1, ESCO2, and GIPC1) were differentially expressed between tumor and normal tissues.

CONCLUSION

Our study discovered promising candidate genes that were causally associated with the survival risk of cervical cancer and thus provided new insights into the genetic etiology of cervical cancer.

MicroRNA-135a-induced formation of CD133+ subpopulation with cancer stem cell properties in cervical cancer

Cancer stem cells (CSCs) play significant roles in tumor initiation. MicroRNA-135a (miR-135a) induced the formation of a CD133+ subpopulation from a human papillomavirus-immortalized cervical epithelial cell line. Compared with the CD133- cells, the CD133+ cells expressed higher levels of miR-135a and OCT4, exhibited significantly higher tumorsphere forming capacity and the time required for tumorsphere formation was shortened in the second generation. Serum induction suppressed the expression of CD133, OCT4 and miR-135a, but increased expression of involucrin in the miR-135a-induced CD133+ cells. The miR-135a-induced CD133+ cells were tumorigenic in a limiting dilution approach in vivo. The cells expressed significantly higher level of active β-catenin and OCT4 than the CD133- counterpart. Wnt3a enhanced the expression of OCT4 and CD133 in cervical cancer cells but failed to enhance CD133 transcription in normal cervical cells. Wnt3a stimulation also increased tumorsphere size and self-renewal of miR-135a-induced CD133+ subpopulation. Wnt/β-catenin inhibition suppressed tumorsphere formation while Wnt3a partially nullified the inhibitory effect. Taken together, miR-135a induced the formation of a subpopulation of cells with CSC properties both in vitro and in vivo and the Wnt/β-catenin signaling pathway is essential to maintain its tumorigenicity.

The Expression and Clinical Significance of miRNA-135a and Bach1 in Colorectal Cancer

Aim

The objective of this study was to explore the correlation between the expression of miRNA-135a and Bach1 in colorectal cancer tissue and the patient's clinical information.

Methods

Sixty patients with colorectal carcinoma were treated as a control group. Real-time quantitative polymerase chain reaction assays and immunohistochemistry methods were performed to detect the expression of miRNA-135a and Bach1 in 60 colorectal carcinomas and adjacent normal tissues, and the clinical and pathologic classifications were also investigated. SPSS 19.00 software was used. All data are represented as mean ± SD of 3 independent experiments. P < 0.05 was considered statistically significant.

Results

miRNA-135a expression levels increased significantly in colon cancer tissues compared with the nontumor control tissues (P < 0.01). miRNA-135a expression levels were higher in stage III/IV than in stage I/II colon cancer patients. The expression level of Bach1 in colorectal cancer was significantly lower (P < 0.01). Bach1 and miRNA-135a were negatively correlated.

Conclusions

The levels of miRNA-135a and Bach1 were opposite: the overexpression of miRNA-135a might downregulate the expression of Bach1, which might be involved in the pathogenesis of colorectal cancer.

GAS5 knockdown suppresses inflammation and oxidative stress induced by oxidized low-density lipoprotein in macrophages by sponging miR-135a

A large number of long non-coding RNAs have been confirmed to play vital roles in regulating various biological processes. Abnormal expression of growth arrest-specific transcript 5 (GAS5) is reported to be involved in the development of atherosclerosis (AS). This work is to explore the detailed mechanism underling how GAS5 regulates AS progression. We found that the abundance of GAS5 was markedly increased, and miR-135a was decreased in AS patient serums and ox-LDL-induced human THP-1 cells dose and time dependently. Interference of GAS5 suppressed inflammation and oxidative stress induced by ox-LDL in THP-1 cells. Mechanistically, GAS5 acted as a molecular sponge of microRNA-135a (miR-135a). Rescue assays indicated that knockdown of miR-135a partially rescued small interference RNA for GAS5-inhibited inflammatory cytokines release and oxidative stress in ox-LDL-triggered THP-1 cells. In conclusion, the absence of GAS5-inhibited inflammatory response and oxidative stress induced by ox-LDL in THP-1 cells via sponging miR-135a, providing a deep insight into the molecular target for AS treatment.

MicroRNA-135a Protects Against Ethanol-Induced Apoptosis in Neural Crest Cells and Craniofacial Defects in Zebrafish by Modulating the Siah1/p38/p53 Pathway

MicroRNAs (miRNAs) are small non-coding RNAs that are involved in various biological processes, including apoptosis, by regulating gene expression. This study was designed to test the hypothesis that ethanol-induced downregulation of miR-135a contributes to ethanol-induced apoptosis in neural crest cells (NCCs) by upregulating Siah1 and activating the p38 mitogen-activated protein kinase (MAPK)/p53 pathway. We found that treatment with ethanol resulted in a significant decrease in miR-135a expression in both NCCs and zebrafish embryos. Ethanol-induced downregulation of miR-135a resulted in the upregulation of Siah1 and the activation of the p38 MAPK/p53 pathway and increased apoptosis in NCCs and zebrafish embryos. Ethanol exposure also resulted in growth retardation and developmental defects that are characteristic of fetal alcohol spectrum disorders (FASD) in zebrafish. Overexpression of miRNA-135a significantly reduced ethanol-induced upregulation of Siah1 and the activation of the p38 MAPK/p53 pathway and decreased ethanol-induced apoptosis in NCCs and zebrafish embryos. In addition, ethanol-induced growth retardation and craniofacial defects in zebrafish larvae were dramatically diminished by the microinjection of miRNA-135a mimics. These results demonstrated that ethanol-induced downregulation of miR-135a contributes to ethanol-induced apoptosis in NCCs by upregulating Siah1 and activating the p38 MAPK/p53 pathway and that the overexpression of miRNA-135a can protect against ethanol-induced apoptosis in NCCs and craniofacial defects in a zebrafish model of FASD.

β-Catenin: oncogenic role and therapeutic target in cervical cancer

Cervical cancer is a common and fatal malignancy of the female reproductive system. Human papillomavirus (HPV) is the primary causal agent for cervical cancer, but HPV infection alone is insufficient to cause the disease. Actually, most HPV infections are sub-clinical and cleared spontaneously by the host immune system; very few persist and eventually develop into cervical cancer. Therefore, other host or environmental alterations could also contribute to the malignant phenotype. One of the candidate co-factors is the β-catenin protein, a pivotal component of the Wnt/β-catenin signaling pathway. β-Catenin mainly implicates two major cellular activities: cell–cell adhesion and signal transduction. Recent studies have indicated that an imbalance in the structural and signaling properties of β-catenin leads to various cancers, such as cervical cancer. In this review, we will systematically summarize the role of β-catenin in cervical cancer and provide new insights into therapeutic strategies.

MiR-135a inhibits non-small cell lung cancer progression by suppressing RAB1B expression and the RAS pathway

Lung cancer is the most common tumor in China and worldwide. Despite advances in diagnosis and therapy, it still represents the most lethal malignancy in industrialized countries. The study of regulatory noncoding RNAs has deepened our understanding of cancer on the molecular and clinical level. In this article, it showed that miR-135a was aberrantly downregulated in non-small cell lung cancer (NSCLC) cells in comparison with normal bronchial epithelial cells, and the expression of miR-135a inhibited proliferation, invasion and metastasis of NSCLC cells in vitro. Moreover, it was demonstrated that miR-135a inhibited the expression of multiple components (including RAS, Raf1, Rac1 and RhoA) of the RAS pathway via RAB1B, which was a novel target of miR-135a. The expression of miR-135a and RAB1B could effectively predict the clinical outcomes of NSCLC. In summary, miR-135a might function as a suppressor of NSCLC cells, and thus could be used as a potential therapeutic target.

Association of human papillomavirus infection and inflammation in cervical cancer

Human papillomavirus (HPV) associated cancers, and in particular cervical cancer, are considered to be directly stimulated by HPV oncogenes. Alternatively, these types of cancers could also be indirectly stimulated by HPV-induced chronic inflammations, which in turn are also caused by HPV oncogenes activity. Chronic inflammation is associated with repeated tissue injury and development of mutations in the vital tumor suppressor genes. Thus, it is important to understand that the persistent HPV infection and its associated chronic inflammation is responsible for the progression of HPV-induced cancers. HPV E5, E6 and E7 could upregulate the expression of cyclooxygenase (COX)-2 and prostaglandin (PG) E2 followed by the activation of the COX-PG pathway. This pathway is assumed to be the main cause of HPV-induced inflammation. Additionally, HPV oncogenes could have an impact on the upregulation of pro-inflammatory cytokines in HPV-positive patients. The upregulation of such cytokines accelerates the incidence of inflammation following HPV infection. Other factors such as microRNAs, which are involved in the inflammation pathways and aging, give rise to the increased level of pro-inflammatory cytokines and could also be responsible for the acceleration of HPV-induced inflammation and consequent cervical cancer. In this review, the exact roles of HPV oncogenes in the occurrence of inflammation in cervical tissue, and the effects of other factors in this event are evaluated.

Downregulation of Siah1 promotes colorectal cancer cell proliferation and migration by regulating AKT and YAP ubiquitylation and proteasome degradation

Background

Colorectal cancer (CRC) is one of the most common malignant tumors in the world. Siah E3 ubiquitin protein ligase 1 (Siah1) has been identified as a tumor suppressor gene and plays an important role in the development of malignant tumors. However, the potential role and molecular mechanism of Siah1 in the development and progression of CRC is still unclear.

Methods

To explore the role and molecular mechanism of Siah1 in the development and progression of CRC, we examined the expression of Siah1 in CRC tissue samples and analyzed its association with progression and prognosis in CRC. In addition, overexpression and knockdown of Siah1 was used to investigate its activity in CRC cells. We also use bioinformatics to analyze and verify the significant roles of Siah1 in critical signaling pathways of CRC.

Results

We found that the expression of Siah1 was significantly downregulated in CRC tissues, and low expression of Siah1 was associated with aggressive TNM staging and poor survival of CRC patients. Moreover, we revealed that overexpression of Siah1 in CRC cells markedly inhibited CRC cell proliferation and invasion in vitro and in vivo, while knockdown of Siah1 enhanced CRC cell proliferation and invasion. Furthermore, we found that Siah1 prohibited cell proliferation and invasion in CRC partially through promoting AKT (the serine-threonine protein kinase) and YAP (yes associated protein) ubiquitylation and proteasome degradation to regulate the activity of MAPK(mitogen-activated protein kinase 1), PI3K-AKT (phosphatidylinositol 3-kinase-the serine-threonine protein kinase) and Hippo signaling pathways.

Conclusions

These findings suggested that Siah1 is a novel potential prognostic biomarker and plays a tumor suppressor role in the development and progression of CRC.

Long Noncoding RNA RAET1K Enhances CCNE1 Expression and Cell Cycle Arrest of Lung Adenocarcinoma Cell by Sponging miRNA-135a-5p

Molecular dysregulation is believed to participate in the onset and progression of lung adenocarcinoma (LUAD). This study aimed to identify and evaluate the potential key long noncoding RNAs (lncRNAs) involved in the significant dysfunctional process of LUAD. We found that lncRNA retinoic acid early transcript 1K (RAET1K) was upregulated in tumor tissues and were correlated with a poor prognosis of patients with LUAD; further, for the first time, we detected the biological roles of RAET1K. Weighted gene correlation network and gene set enrichment analysis revealed that high RAET1K expression is related to cell cycle dysfunction through upregulated cyclin E1 (CCNE1) by targeting miR-135. The dual-luciferase reporter gene assay was performed to clarify the binding relationship between RAET1K and miR-135a-5p in transgenic A549 and H1299 cells. Real-time PCR and Western blot analyses showed that RAET1K overexpression and miR-135a-5p inhibition exerted a strong synergistic effect on CCNE1 expression, and cell cycle flow cytometry analysis was used to confirm the arrest of A549 and H1299 cells at the G1/S phase. The lncRNA RAET1K/miR-135a-5p axis might participate in the regulation of LUAD progression by influencing CCNE1 expression and the accumulation of cells arrested at the G1/S phase boundary.

MiR-135a biogenesis and regulation in malignancy: a new hope for cancer research and therapy

MicroRNAs (miRNAs) are evolutionarily conserved small non-coding RNAs that affect posttranscriptional regulation by binding to the 3′-untranslated region of target messenger RNAs. MiR-135a is a critical miRNA that regulates gene expression, and many studies have focused on its function in cancer research. MiR-135a is dysregulated in various cancers and regulates cancer cell proliferation and invasion via several signaling pathways, such as the MAPK and JAK2/STAT3 pathways. MiR-135a has also been found to promote or inhibit the epithelial-mesenchymal transition and chemoresistance in different cancers. Several studies have discovered the value of miR-135a as a novel biomarker for cancer diagnosis and prognosis. These studies have suggested the potential of therapeutically manipulating miR-135a to improve the outcome of cancer patients. Although these findings have demonstrated the role of miR-135a in cancer progression and clinical applications, a number of questions remain to be answered, such as the dual functional roles of miR-135a in cancer. In this review, we summarize the available studies regarding miR-135a and cancer, including background on the biogenesis and expression of miR-135a in cancer and relevant signaling pathways involved in miR-135a-mediated tumor progression. We also focus on the clinical application of miR-135a as a biomarker in diagnosis and as a therapeutic agent or target in cancer treatment, which will provide a greater level of insight into the translational value of miR-135a.

Aberrantly enhanced melanoma-associated antigen (MAGE)-A3 expression facilitates cervical cancer cell proliferation and metastasis via actuating Wnt signaling pathway

BACKGROUND

The over-expression of melanoma-associated antigen (MAGE)-A3 in cervical cancer (CC) has been observed in our previous study, suggesting that it possibly take a vital role during the development and metastasis of CC. The present study aimed to investigate the biological function of MAGE-A3 in the progression of CC and explore how it executes its roles.

METHODS

The mRNA expression of MAGE-A3 in End1/E6E7 and CC cell lines (HeLa, SiHa and C33A) was measured by real-time quantitative reverse transcription PCR (qRT-PCR). Loss- and gain-of-function methods were used to assess the effect of MAGE-A3 on the proliferative, migratory and invasive abilities of HeLa and SiHa cells. Western blot was performed to measure the expression levels of proteins related to epithelial-mesenchymal transition (EMT) and proteins in the Wnt signaling pathway. In vivo tumorigenesis assay was conducted to evaluate the effect of MAGE-A3 on tumor growth.

RESULTS

MAGE-A3 expression was significantly up-regulated in CC cell lines (HeLa, SiHa and C33A) compared with that in End1/E6E7 cell line. Knockdown of MAGE-A3 could significantly suppress migration, invasion and proliferation in HeLa cells; whereas, overexpression of MAGE-A3 in SiHa cells presented the opposite results. Moreover, knockdown of MAGE-A3 presented a suppressive effect on the activation of EMT and Wnt signaling pathway in HeLa cells, whilst up-regulation of MAGE-A3 exhibited the opponent outcomes in SiHa cells. Through in vivo tumorigenesis assay, we further verified that MAGE-A3 acted as a facilitator in tumor growth.

CONCLUSIONS

MAGE-A3 is overexpressed in CC cells and possibly facilitates the viability and motility of CC cells via modulating EMT and Wnt signaling. This study implied that MAGE-A3 might be a potential therapeutic target as well as a prognosis predictor for patients with CC.

Long noncoding RNA HOTAIR knockdown inhibits autophagy and epithelial-mesenchymal transition through the Wnt signaling pathway in radioresistant human cervical cancer HeLa cells

Cervical cancer is one of the most common female malignancies around the world, and radiation resistance is a major obstacle to cancer therapy. Previously, overexpression of the long noncoding ribonucleic acid (RNA) (lncRNA) HOX transcript antisense RNA (HOTAIR) has been found to be associated with the invasion and metastasis capacities of several epithelial cancers, including cervical cancer. To gain insights into the molecular mechanisms of HOTAIR in cervical cancer resistance to radiotherapy, we investigated cellular autophagy and epithelial-to-mesenchymal transition (EMT) in radioresistant human cervical cancer HeLa cells when HOTAIR was suppressed. HOTAIR levels were quantified in cancerous and noncancerous cervical tissues obtained from 108 patients with cervical cancer. Next, we inhibited HOTAIR by RNA interference and activated the Wnt signaling pathway by LiCl in radioresistant HeLa cells to investigate the regulatory mechanisms for the HOTAIR mediating Wnt signaling pathway. We determined that the upregulated HOTAIR may contribute to cervical cancer progression. We found that the short interfering ribonucleic acid (siRNA)-mediated knockdown of HOTAIR disturbed the Wnt signaling pathway, reduced autophagy, inhibited EMT, decreased cell proliferation, and induced apoptosis in radioresistant HeLa cells. It is worthy to note that the combination treatment of siRNA-HOTAIR and LiCl demonstrated that the activation of the Wnt signaling pathway is responsible for the beneficial effect of HOTAIR knockdown in enhancing sensitivity to radiotherapy in radioresistant HeLa cells. Together, our results revealed an important role of HOTAIR in regulating cervical cancer resistance to radiotherapy. Functional suppression of HOTAIR could enhance sensitivity to radiotherapy by reduction of autophagy and reversal of EMT through the suppression of the Wnt signaling pathway.

PHF19 promotes the proliferation, migration, and chemosensitivity of glioblastoma to doxorubicin through modulation of the SIAH1/β-catenin axis

PHD finger protein 19 (PHF19), a critical component of the polycomb repressive complex 2 (PRC2), is crucial for maintaining the repressive transcriptional activity of several developmental regulatory genes and plays essential roles in various biological processes. Abnormal expression of PHF19 causes dysplasia or serious diseases, including chronic myeloid disorders and tumors. However, the biological functions and molecular mechanisms of PHF19 in glioblastoma (GBM) remain unclear. Here, we demonstrated that PHF19 expression was positively associated with GBM progression, including cell proliferation, migration, invasion, chemosensitivity, and tumorigenesis. Using XAV-939, a Wnt/β-catenin inhibitor, we found that the effects of PHF19 on GBM cells were β-catenin-dependent. We also demonstrated that PHF19 expression was positively correlated with cytoplasmic β-catenin expression. PHF19 stabilized β-catenin by inhibiting the transcription of seven in absentia homolog 1 (SIAH1), an E3 ubiquitin ligase of β-catenin, through direct binding to the SIAH1 promoter region. Taken together, our results revealed the novel PHF19-SIAH1–β-catenin axis as a potential and promising therapeutic target.

Knockdown of miR-299-5p inhibits the progression of hepatocellular carcinoma by targeting SIAH1

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. MiR-299-5p has been demonstrated to play important roles in multiple human cancers. Nevertheless, little is known about the detailed function and molecular mechanism of miR-299-5p on HCC progression.

METHODS

Quantitative real-time PCR (qRT-PCR) assay was used to assess the expression patterns of miR-299-5p and siah E3 ubiquitin protein ligase 1 (SIAH1) in HCC tissues and cell lines. Loss-of-function experiments were performed to explore the effect of miR-299-5p on HCC progression in vitro and in vivo. Target predicted by software algorithms, the connection between miR-299-5p and SIAH1 was verified by dual-luciferase reporter assay, qRT-PCR and western blot analysis. Subsequently, anti-miR-299-5p and si-SIAH1 were cotransfected into LM9 and Huh-7 cells to further explore whether the regulatory effect of miR-299-5p on HCC was mediated by SIAH1.

RESULTS

qRT-PCR assay revealed that miR-299-5p was upregulated and SIAH1 was downregulated in HCC tissues and cell lines. Moreover, miR-299-5p knockdown suppressed HCC progression in vitro and in vivo. In addition, anti-miR-299-5p-mediated regulatory effect on HCC cells was abated following the restoration of SIAH1 expression.

CONCLUSIONS

MiR-299-5p knockdown suppressed the progression of HCC by targeting SIAH1, highlighting its role as a potential biomarker and therapeutic target of HCC.

Loss of Estrogen-Regulated MIR135A1 at 3p21.1 Promotes Tamoxifen Resistance in Breast Cancer

The dysregulation of miRNAs has been increasingly recognized as a critical mediator of cancer development and progression. Here, we show that frequent deletion of the MIR135A1 locus is associated with poor prognosis in primary breast cancer. Forced expression of miR-135a decreased breast cancer progression, while inhibition of miR-135a with a specific miRNA sponge elicited opposing effects, suggestive of a tumor suppressive role of miR-135a in breast cancer. Estrogen receptor alpha (ERα) bound the promoter of MIR135A1 for its transcriptional activation, whereas tamoxifen treatment inhibited expression of miR-135a in ERα+ breast cancer cells. miR-135a directly targeted ESR1, ESRRA, and NCOA1, forming a negative feedback loop to inhibit ERα signaling. This regulatory feedback between miR-135a and ERα demonstrated that miR-135a regulated the response to tamoxifen. The tamoxifen-mediated decrease in miR-135a expression increased the expression of miR-135a targets to reduce tamoxifen sensitivity. Consistently, miR-135a expression was downregulated in ERα+ breast cancer cells with acquired tamoxifen resistance, while forced expression of miR-135a partially resensitized these cells to tamoxifen. Tamoxifen resistance mediated by the loss of miR-135a was shown to be partially dependent on the activation of the ERK1/2 and AKT pathways by miR-135a-targeted genes. Taken together, these results indicate that deletion of the MIR135A1 locus and decreased miR-135a expression promote ERα+ breast cancer progression and tamoxifen resistance.Significance: Loss of miR-135a in breast cancer disrupts an estrogen receptor-induced negative feedback loop, perpetuating disease progression and resistance to therapy.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/17/4915/F1.large.jpg Cancer Res; 78(17); 4915-28. ©2018 AACR.

MicroRNA-135a-3p is downregulated and serves as a tumour suppressor in ovarian cancer by targeting CCR2

MicroRNAs have been demonstrated to play a crucial role in the development of ovarian cancer. Many studies prove that forms of miR-135a, including miR-135a-5p and miR-135a-3p, serve as tumour suppressors in multiple cancers. Nevertheless, the precise function of miR-135a-3p and the molecular mechanisms underlying the involvement of miR-135a-3p in ovarian carcinoma cell growth and metastasis remain largely unknown. Herein, we report that miR-135a-3p expression was significantly downregulated in ovarian carcinoma tissues compared with corresponding adjacent non-tumour tissues. Ectopic miR-135a-3p expression inhibited ovarian carcinoma cell proliferation, migration and invasion in vitro. Additionally, the overexpression of miR-135a-3p inhibited epithelial-mesenchymal transition (EMT) in ovarian cancer cells. A luciferase reporter assay confirmed that the C-C chemokine receptor type 2 (CCR2) gene was the target of miR-135a-3p. In addition, CCR2 depletion mimicked the inhibitory effects of miR-135a-3p on ovarian cancer cells in vitro. Rescue experiments using CCR2 overexpression further verified that CCR2 was a functional target of miR-135a-3p. Xenograft model assays demonstrated that miR-135a-3p functions as an anti-oncogene by targeting CCR2 in vivo. Taken together, these data prove that miR-135a-3p serves as a tumour suppressor gene in ovarian cancer by regulating CCR2.

Fascin protein stabilization by miR-146a implicated in the process of a chronic inflammation-related colon carcinogenesis model

OBJECTIVE

In sporadic colon tumors, multistep process of well-known genetic alterations accelerates carcinogenesis; however, this does not appear to be the case in inflammation-related ones. We previously established a model of inflammation-related colon carcinogenesis using human colonic adenoma cells, and identified fascin as a driver gene of this process. We analyzed the microRNAs involved in the stable fascin expression in colon adenocarcinoma cells.

MATERIALS AND METHODS

miRNA microarray analysis was performed using FPCK-1-1 adenoma cells and its-derived FPCKpP₁-4 adenocarcinoma cells through chronic inflammation. To assess the involvement of miRNA in the inflammation-related carcinogenesis, sphere-forming ability, expression of colon cancer stemness markers, and stability of fascin protein via the proteasome using tough decoy RNA technique.

RESULTS

We found that 17 miRNAs including miR-146a were upregulated and 16 miRNAs were downregulated in FPCKpP₁-4 adenocarcinoma cells. We revealed that miR-146a in the adenocarcinoma cells brought about acquisition of sphere formation, cancer stemness, and inhibition of proteasomal degradation of the fascin protein.

CONCLUSIONS

We found that stable fascin expression is brought about via the inhibition of proteasome degradation by miR-146a in the process of a chronic inflammation-related colon carcinogenesis.

MicroRNAs as markers of progression in cervical cancer: a systematic review

BACKGROUND

Invasive cervical cancer (ICC) is caused by high-risk human papillomavirus types (HR-HPVs) and is usually preceded by a long phase of intraepithelial neoplasia (CIN). Before invasion, (epi) genetic changes, potentially applicable as molecular markers within cervical screening, occur in HPV host cells. Epigenetic alterations, such as dysregulation of microRNA (miRNA) expression, are frequently observed in ICC. The mechanisms and role of miRNA dysregulation in cervical carcinogenesis are still largely unknown.

METHODS

We provide an overview of the studies investigating miRNA expression in relation to ICC progression, highlighting their common outcomes and their weaknesses/strengths. To achieve this, we systematically searched through Pubmed database all articles between January 2010 and December 2017.

RESULTS

From the 24 studies retrieved, miR-29a and miR-21 are the most frequently down- and up-regulated in ICC progression, respectively. Microarray-based studies show a small overlap, with miR-10a, miR-20b, miR-9, miR-16 and miR-106 found repeatedly dysregulated. miR-34a, miR-125 and miR-375 were also found dysregulated in cervical exfoliated cells in relation to cancer progression.

CONCLUSIONS

The pivotal role of miRNAs in ICC progression and initial development is becoming more and more relevant. Available studies are essentially based on convenience material, entailing possible selection bias, and frequently of small size: all these points still represent a limitation to a wide comprehension of miRNAs relevant for ICC. The targeted approach instead of a genome-wide investigation still precludes the identification of all the relevant miRNAs in the process. The implementation of deep sequencing on large scale population-based studies will help to discover and validate the relation between altered miRNA expression and CC progression for the identification of biomarkers. Optimally, once explored on a miRNome scale, small specific miRNA signatures maybe used in the context of screening.

miR-135a inhibits tumor metastasis and angiogenesis by targeting FAK pathway

Tumor metastasis has been the major cause of recurrence and death in patients with gastric cancer. Here, we find miR-135a has a decreased expression in the metastatic cell lines compared with its parental cell lines by analyzing microRNA array. Further results show that miR-135a is downregulated in the majority of human gastric cancer tissues and cell lines. Decreased expression of miR-135a is associated with TNM stage and poor survival. Besides, regaining miR-135a in gastric cancer cells obviously inhibits tumor growth, migration, invasion and angiogenesis by targeting focal adhesion kinase (FAK) pathway. Bioinformatics analysis and molecular experiments further prove that miR-135a is a novel downstream gene of tumor suppressor p53. Blocking FAK with its inhibitor can also enhance miR-135a expression through inducing p53. In summary, this study reveals the expression and function of miR-135a in gastric cancer and uncovers a novel regulatory mechanism of miR-135a.

miR-450b-5p induced by oncogenic KRAS is required for colorectal cancer progression

The development and progression of CRC are regarded as a complicated network and progressive event including genetic and/or epigenetic alterations. Recent researches revealed that MicroRNAs are biomarkers and regulators of CRC progression. Analyses of published microarray datasets revealed that miR-450b-5p was highly up-regulated in CRC tissues. In addition, high expression of miR-450b-5p was significantly associated with KRAS mutation. However, the role of miR-450b-5p in the progression of CRC remains unknown. Here, we sought to validate the expression of miR-450b-5p in CRC tissues and investigate the role and underlying mechanism of miR-450b-5p in the progression of CRC. The results revealed that miR-450b-5p was up-regulated in CRC tissues, high expression level of miR-450b-5p was positively associated with poor differentiation, advanced TNM classification and poor prognosis. Moreover, miR-450b-5p was especially high in KRAS-mutated cell lines and could be up-regulated by KRAS/AP-1 signaling. Functional validation revealed that overexpression of miR-450b-5p promoted cell proliferation and tumor growth while inhibited apoptosis of CRC cells. Furthermore, we demonstrated that miR-450b-5p directly bound the 3′-UTRs of SFRP2 and SIAH1, and activated Wnt/β-Catenin signaling. In conclusion, miR-450b-5p induced by oncogenic KRAS is required for colorectal cancer progression. Collectively, our work helped to understand the precise role of miR-450b-5p in the progression of CRC, and might promote the development of new therapeutic strategies against CRC.

Wnt signaling in cervical cancer?

Cervical cancer (CC) is the second most common malignant cancer in women. CC is difficult to diagnose, has a high recurrence rate, and is resistant to systemic therapies; as a result, CC patients have a relatively poor prognosis. One potential link to CC is the Wnt signaling pathway and its downstream effectors, which regulate cell differentiation, proliferation, migration, and fate. The aberrant activation of Wnt signaling is associated with various cancers, including CC. Recent studies have shown that activating or inhibiting the intracellular signal transduction in this pathway can regulate cancer cell growth and viability. This review will summarize the experimental evidence supporting the significance of the Wnt signaling pathway in CC, and will also discuss the current clinical role of Wnt signaling in CC diagnosis, therapy, and prognosis.

miR-135a promotes gastric cancer progression and resistance to oxaliplatin

Resistance to oxaliplatin (OXA)-based chemotherapy regimens continues to be a major cause of gastric cancer (GC) recurrence and metastasis. We analyzed GC samples and matched non-tumorous control stomach tissues from 280 patients and found that miR-135a was overexpressed in GC samples relative to control tissues. Tumors with high miR-135a expression were more likely to have aggressive characteristics (high levels of carcino-embryonic antigen, vascular invasion, lymphatic metastasis, and poor differentiation) than those with low levels. Patients with greater tumoral expression of miR-135a had shorter overall survival times and times to disease recurrence. Furthermore, miR-135a, which promotes the proliferation and invasion of OXA-resistant GC cells, inhibited E2F transcription factor 1 (E2F1)-induced apoptosis by downregulating E2F1 and Death-associated protein kinase 2 (DAPK2) expression. Our results indicate that higher levels of miR-135a in GC are associated with shorter survival times and reduced times to disease recurrence. The mechanism whereby miR-135a promotes GC pathogenesis appears to be the suppression of E2F1 expression and Sp1/DAPK2 pathway signaling.

microRNA-mediated regulation of splicing factors SRSF1, SRSF2 and hnRNP A1 in context of their alternatively spliced 3'UTRs

SRSF1, SRSF2 and hnRNP A1 are splicing factors that regulate the expression of oncogenes and tumor suppressors. SRSF1 and SRSF2 contribute to the carcinogenesis in the kidney. Despite their importance, the mechanisms regulating their expression in cancer are not entirely understood. Here, we investigated the microRNA-mediated regulation of SRSF1, SRSF2 and hnRNP A1 in renal cancer. The expression of microRNAs predicted to target SRSF1, SRSF2 and hnRNP A1 was disturbed in renal tumors compared with controls. Using qPCR, Western blot/ICC and luciferase reporter system assays we identified microRNAs that contribute to the regulation of expression of SRSF1 (miR-10b-5p, miR-203a-3p), SRSF2 (miR-183-5p, miR-200c-3p), and hnRNP A1 (miR-135a-5p, miR-149-5p). Silencing of SRSF1 and SRSF2 enhanced the expression of their targeting microRNAs. miR-183-5p and miR-200c-3p affected the expression of SRSF2-target genes, TNFRSF1B, TNFRSF9, CRADD and TP53. 3'UTR variants of SRSF1 and SRSF2 differed by the presence of miRNA-binding sites. In conclusion, we identified a group of microRNAs that contribute to the regulation of expression of SRSF1, SRSF2 and hnRNP A1. The microRNAs targeting SRSF1 and SRSF2 are involved in a regulatory feedback loop. microRNAs miR-183-5p and miR-200c-3p that target SRSF2, affect the expression of genes involved in apoptotic regulation.

Factor VII-Induced MicroRNA-135a Inhibits Autophagy and Is Associated with Poor Prognosis in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common and aggressive malignancies worldwide. Treatment outcomes remain poor mainly due to lack of good diagnostic/prognostic markers and limited therapeutic strategies. We previously characterized aberrant activation of the TF/FVII/PAR2 pathway, which subsequently results in decreased autophagy, as a crucial event in malignant progression of HCC.

Here, we identified miR-135a as a highly upregulated miRNA in HCC in response to TF/FVII/PAR2 activation. Analyzing 103 HCC patient specimens, we confirmed that miR-135a was frequently elevated in HCC tissues with higher FVII expression compared to adjacent non-cancerous counterparts. Increased miR-135a levels in HCC were also associated with tumor staging, recurrence, microvascular invasion, and decreased disease-free survival. We subsequently identified Atg14, a key component that regulates the formation of autophagosome as a direct target of miR-135a. Ectopic expression of miR-135a suppressed Atg14 levels and inhibited the autophagic processes. Our results indicate strong positive correlations between miR-135a levels and malignant behaviors in HCC patients and also suggest novel functions of miR-135a in regulation of autophagy, which could be useful as a potential target for prognostic and therapeutic uses.

Long non-coding RNAs on the stage of cervical cancer (Review)

Cervical cancer is one of most malignant gynecological tumors. However, effective means for diagnosing and treating cervical cancer have yet to be identified. A few decades ago, long non-coding RNAs (lncRNAs) were regarded as useless parts of the genome, however, increasing data have demonstrated the importance of lncRNAs in the diagnosis and treatment of cervical cancers. The aim of the present study is to summarize the role(s) of HOTAIR, MALAT1, CCAT2, SPRY4-IT1, RSU1P2, CCHE1, lncRNA-EBIC and PVT1. Approximately 14 lncRNAs are involved in cervical cancer and several important proteins, miRNAs and other molecules and play crucial roles in a few traditional signaling pathways that have been proven to be related to those lncRNAs. In conclusion, lncRNAs may be useful as exact treatment targets and diagnostic biomarkers for improving therapies in cervical cancer patients and lncRNAs may contribute to effective diagnosis and treatment methods for cervical cancer.

Membrane-bound β-catenin degradation is enhanced by ETS2-mediated Siah1 induction in Helicobacter pylori-infected gastric cancer cells

β-catenin has two different cellular functions: intercellular adhesion and transcriptional activity. The E3 ubiquitin ligase Siah1 causes ubiquitin-mediated degradation of the cytosolic β-catenin and therefore, impairs nuclear translocation and oncogenic function of β-catenin. However, the effect of Siah1 on the cell membrane bound β-catenin has not been studied. In this study, we identified that the carcinogenic bacterium H. pylori increased ETS2 transcription factor-mediated Siah1 protein expression in gastric cancer cells (GCCs) MKN45, AGS and Kato III. Siah1 protein level was also noticeably higher in gastric adenocarcinoma biopsy samples as compared to non-cancerous gastric epithelia. Siah1 knockdown significantly decreased invasiveness and migration of H. pylori-infected GCCs. Although, Siah1 could not increase degradation of the cytosolic β-catenin and its nuclear translocation, it enhanced degradation of the membrane-bound β-catenin in the infected GCCs. This loss of membrane-bound pool of β-catenin was not associated with the proteasomal degradation of E-cadherin. Thus, this work delineated the role of Siah1 in increasing invasiveness of H. pylori-infected GCCs.

Characterization of the microRNA profile in early-stage cervical squamous cell carcinoma by next-generation sequencing

Squamous cell carcinoma (SCC) is histologically the most prominent type of cervical cancer. There is accumulating evidence suggesting that microRNAs (miRNAs) play important regulatory roles in the biological processes of cervical squamous cell carcinoma (CSCC). Deciphering the miRNA regulatory network in CSCC could deepen our understanding at the molecular level of CSCC initiation and progression. In the present study, we performed next‑generation sequencing (NGS) to profile miRNA expression in 3 pairs of early-stage CSCC samples. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to verify primary findings in another 20 pairs of CSCC samples. We identified 37 known miRNAs that exhibited significant alterations in expression (2-fold change or greater), among which 8 miRNAs were upregulated and 29 miRNAs were downregulated. Nine of these miRNAs were selected for further qRT-PCR validation. A novel miRNA candidate was also reported for the first time in the present study to be upregulated. The Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that its target genes were involved in MAPK, calcium and adherent junction signaling pathways. The present study systematically characterized the miRNA expression variation in early-stage CSCC and provides novel biomarkers for diagnosis and treatment as well as an opportunity for further investigation of the molecular mechanisms underlying the pathogenesis and development of CSCC.

The human papillomavirus E7 oncoprotein as a regulator of transcription

High-risk human papillomaviruses (HPVs) encode oncoproteins which manipulate gene expression patterns in the host keratinocytes to facilitate viral replication, regulate viral transcription, and promote immune evasion and persistence. In some cases, oncoprotein-induced changes in host cell behavior can cause progression to cancer, but a complete picture of the functions of the viral oncoproteins in the productive HPV life cycle remains elusive. E7 is the HPV-encoded factor most responsible for maintaining cell cycle competence in differentiating keratinocytes. Through interactions with dozens of host factors, E7 has an enormous impact on host gene expression patterns. In this review, we will examine the role of E7 specifically as a regulator of transcription. We will discuss mechanisms of regulation of cell cycle-related genes by E7 as well as genes involved in immune regulation, growth factor signaling, DNA damage responses, microRNAs, and others pathways. We will also discuss some unanswered questions about how transcriptional regulation by E7 impacts the biology of HPV in both benign and malignant conditions.

The oncoprotein HBXIP suppresses gluconeogenesis through modulating PCK1 to enhance the growth of hepatoma cells

Hepatitis B X-interacting protein (HBXIP) as an oncoprotein plays crucial roles in the development of cancer, involving glucose metabolism reprogramming. In this study, we are interested in whether the oncoprotein HBXIP is involved in the modulation of gluconeogenesis in liver cancer. Here, we showed that the expression level of phosphoenolpyruvate carboxykinase (PCK1), a key enzyme of gluconeogenesis, was lower in clinical hepatocellular carcinoma (HCC) tissues than that in normal tissues. Mechanistically, HBXIP inhibited the expression of PCK1 through down-regulating transcription factor FOXO1 in hepatoma cells, and up-regulated miR-135a targeting the 3'UTR of FOXO1 mRNA in the cells. In addition, HBXIP increased the phosphorylation levels of FOXO1 protein by activating PI3K/Akt pathway, leading to the export of FOXO1 from nucleus to cytoplasm. Strikingly, over-expression of PCK1 could abolish the HBXIP-promoted growth of hepatoma cells in vitro and in vivo. Thus, we conclude that the oncoprotein HBXIP is able to depress the gluconeogenesis through suppressing PCK1 to promote hepatocarcinogenesis, involving miR-135a/FOXO1 axis and PI3K/Akt/p-FOXO1 pathway. Our finding provides new insights into the mechanism by which oncoprotein HBXIP modulates glucose metabolism reprogramming in HCC.

Up-regulation of Siah1 by ethanol triggers apoptosis in neural crest cells through p38 MAPK-mediated activation of p53 signaling pathway

Seven in absentia homolog 1 (Siah1) is one of the E3 ubiquitin ligases and plays a key role in regulating target protein degradation. This study was designed to test the hypothesis that Siah1 mediates ethanol-induced apoptosis in NCCs through p38 MAPK-mediated activation of the p53 signaling pathway. We found that exposure of NCCs to ethanol resulted in the increases in the total protein levels of p53 and the phosphorylation of p53 at serine 15. Ethanol exposure also resulted in a significant increase in the phosphorylation of p38 MAPK. Knock-down of Siah1 dramatically reduced the ethanol-induced increase in the phosphorylation of p38 MAPK. Knock-down of Siah1 by siRNA or down-regulation of p38 MAPK by either siRNA or inhibitor significantly diminished ethanol-induced accumulations of p53 and the phosphorylation of p53. In addition, ethanol exposure resulted in a significant increase in the expression of p53 downstream targets and apoptosis in NCCs, which can be significantly diminished by down-regulation of Siah1 with siRNA. Knock-down of p38 MAPK by siRNA also dramatically reduced the ethanol-induced apoptosis. These results demonstrate that Siah1 plays a crucial role in ethanol-induced apoptosis in NCCs, and that the up-regulation of Siah1 by ethanol can trigger apoptosis through p38 MAPK-mediated activation of the p53 signaling pathway.

Expression and functional analysis of the Wnt/beta-catenin induced mir-135a-2 locus in embryonic forebrain development

BACKGROUND

Brain size and patterning are dependent on dosage-sensitive morphogen signaling pathways - yet how these pathways are calibrated remains enigmatic. Recent studies point to a new role for microRNAs in tempering the spatio-temporal range of morphogen functions during development. Here, we investigated the role of miR-135a, derived from the mir-135a-2 locus, in embryonic forebrain development.

METHOD

1. We characterized the expression of miR-135a, and its host gene Rmst, by in situ hybridization (ish). 2. We conditionally ablated, or activated, beta-catenin in the dorsal forebrain to determine if this pathway was necessary and/or sufficient for Rmst/miR-135a expression. 3. We performed bioinformatics analysis to unveil the most predicted pathways targeted by miR-135a. 4. We performed gain and loss of function experiments on mir-135a-2 and analyzed by ish the expression of key markers of cortical hem, choroid plexus, neocortex and hippocampus.

RESULTS

1. miR-135a, embedded in the host long non-coding transcript Rmst, is robustly expressed, and functional, in the medial wall of the embryonic dorsal forebrain, a Wnt and TGFβ/BMP-rich domain. 2. Canonical Wnt/beta-catenin signaling is critical for the expression of Rmst and miR-135a, and the cortical hem determinant Lmx1a. 3. Bioinformatics analyses reveal that the Wnt and TGFβ/BMP cascades are among the top predicted pathways targeted by miR-135a. 4. Analysis of mir-135a-2 null embryos showed that dorsal forebrain development appeared normal. In contrast, modest mir-135a-2 overexpression, in the early dorsal forebrain, resulted in a phenotype resembling that of mutants with Wnt and TGFβ/BMP deficits - a smaller cortical hem and hippocampus primordium associated with a shorter neocortex as well as a less convoluted choroid plexus. Interestingly, late overexpression of mir-135a-2 revealed no change.

CONCLUSIONS

All together, our data suggests the existence of a Wnt/miR-135a auto-regulatory loop, which could serve to limit the extent, the duration and/or intensity of the Wnt and, possibly, the TGFβ/BMP pathways.

MicroRNA-183 functions as the tumor suppressor via inhibiting cellular invasion and metastasis by targeting MMP-9 in cervical cancer

OBJECTIVE

MicroRNAs have been reported to play an important role in the invasion and metastasis of cervical cancer. miR-183 was found to inhibit or promote the invasion and metastasis of multiple solid tumors. However, the roles of miR-183 in cervical cancer are unclear.

METHODS

In this study, miR-183 expression levels were measured in 53 cervical cancer and 13 normal cervical tissues by qRT-PCR. The effects of forced expression of miR-183 on cervical cancer cells invasion and metastasis were investigated using Transwell uncoated or coated with growth factor-reduced Matrigel for migration or invasion assays, respectively.

RESULTS

We found that miR-183 expression levels were significantly down-regulated in cervical cancer tissues compared with normal tissues (0.15±0.011 to 0.86±0.049). Ectopic expression of miR-183 resulted in the suppression of invasion and migration of cervical cancer cell lines, siha and Hela cells (p<0.0001). Bioinformatics analysis revealed that MMP-9 was the potential target of miR-183 and it was found that MMP-9 was remarkably up-regulated in cervical cancer. Furthermore, a dual-luciferase reporter assay showed that MMP-9 as a target of miR-183 (p<0.0001). The invasion and metastasis ability of siha and Hela was suppressed when MMP-9 was down-regulated in vitro (p<0.0001).

CONCLUSIONS

In conclusion, our study revealed that miR-183 might be a tumor suppressor via inhibiting the invasion and metastasis of cervical cancer cells through targeting MMP-9, indicating that miR-183 may be a novel potential therapeutic target for cervical cancer.

LncRNAs: key players and novel insights into cervical cancer

Cervical cancer contributed the second highest number of deaths in female cancers, exceeded only by breast cancer, carrying high risks of morbidity and mortality. There was a great need and urgency in searching novel treatment targets and prognosis biomarkers to improve the survival rate of cervical cancer patients. Many long non-coding RNAs (lncRNAs) were emerging as pivotal regulators in various biological processes and took vitally an effect on the oncogenesis and progression of cervical cancer. In this review, we summarized the origin and overview function of lncRNAs; highlighted the roles of lncRNAs in cervical cancer in terms of prognosis and tumor progression, invasion and metastasis, apoptosis, and radio-resistance; and outlined the molecular mechanisms of lncRNAs in cervical cancer from the aspects of the interaction of lncRNAs with proteins/mRNAs (especially in HPV protein) and miRNAs, as well as RNA N-methyladenosine (m6A) methylation of lncRNAs. Meanwhile, the application of lncRNAs as biomarkers in cervical cancer prognosis and predictors for metastasis was also discussed. An overview of these researches will be valuable for broadening horizons into mechanisms, selection of meritorious biomarkers for diagnosis as well as prognosis, and future targeted therapy of cervical cancer.

The ubiquitin ligase Siah is a novel regulator of Zeb1 in breast cancer

Elucidating the mechanisms that underlie metastasis is of paramount importance to understanding tumor progression and to the development of novel therapeutics. Epithelial to Mesenchymal Transition (EMT) plays a vital role in tumor cell dissemination and is regulated by a core cassette of transcription factors. Despite recent advances, the molecular pathways that regulate the EMT program have not yet been fully delineated. We show that Siah ubiquitin ligases regulate Zeb1 protein, a key EMT transcription factor. The induction of EMT in breast cancer cells leads to the down-regulation of Siah, while the loss of Siah induces a mesenchymal phenotype, concurrent with an up-regulation of Zeb1. Overexpression of Siah in vitro mediates Zeb1 degradation, which can be blocked with a Siah peptide inhibitor. Thus, this work demonstrates that Siah is a novel regulator of EMT. This work is the first to identify a mechanism of post-translational regulation of the key Epithelial to Mesenchymal Transition transcription factor Zeb1.

MicroRNAs are involved in cervical cancer development, progression, clinical outcome and improvement treatment response (Review)

Cervical cancer (CC) is the third most diagnosed cancer among females worldwide and the fourth cause of cancer-related mortality. Prophylactic HPV vaccines and traditional pap-smear screening are undoubtedly capable of decreasing the incidence and mortality of CC. However, a large number of females succumb to the disease each year due to late diagnosis and resistance to conventional treatments. Thus, it is necessary to identify new molecular markers to predict the clinical outcome and to design powerful treatments. MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression and are involved in the modulation of several cell pathways associated with progression from pre-malignant to invasive and metastatic disease, increasing tumor malignancy. The aim of this review was to summarize the recent data that describe the important role of miRNAS involved in CC in order to determine their potential as prognostic biomarkers and as therapy targets. Studies of >40 miRNAs with roles in cancer regulation were identified. We also identified 17 miRNAs associated with progression, 12 involved with clinical outcome and 7 that improved CC treatment response. The present review is expected to broaden understanding of the functional role and potential clinical uses of miRNAs in CC.

Overexpression of miR-21 promotes the proliferation and migration of cervical cancer cells via the inhibition of PTEN

The oncogenic miR-21 has been widely recognized to promote the development and progression of various types of malignant tumors, but not cervical cancers. The aim of this study was to examine the expression of miR-21 and PTEN in cervical cancer specimens using quantitative PCR. The miR-21 level was then manipulated in the cervical cancer lines and the regulation of miR-21 on the proliferation, migration and invasion of cervical cancer cells was determined. Additionally, we determined the role of PTEN in the miR-21-regulated proliferation, migration and invasion of cervical cancer cells. miR-21 was upregulated in the cervical cancer specimens, negatively correlating with the PTEN mRNA level. Transfection of the miR-21 mimics was markedly promoted, whereas the miR-21 inhibitor suppressed the proliferation, migration and invasion of cervical cancer cells, with a significant inhibition of PTEN expression. In addition, the overexpression of PTEN markedly inhibited the proliferation and migration of the cervical cancer cells. The present study showed the upregulation of miR-21 in invasive cervical cancers, and confirmed the promotion of miR-21 with regard to the proliferation, migration and invasion in cervical cancer cells via inhibiting the PTEN expression. To the best of our knowledge, this is the first study to confirm that the miR-21/PTEN pathway promotes cervical cancer.

MicroRNA-494 promotes cervical cancer proliferation through the regulation of PTEN

The phosphoinositide 3-kinase (PI3K)/Akt signaling pathway appears to be a key regulator in cervical carcinogenesis. The phosphatase and tensin homolog deleted on chromosome 10 (PTEN) protein is principally involved in the homeostatic maintenance of PI3K/Akt signaling and PTEN has been identified to play an important role in the occurrence and development of cervical cancer. MicroRNA (miRNA)-494 has been proven to be involved in the carcinogenesis and development of various types of cancer by directly targeting PTEN. However the role, mechanism and clinical significance of miR-494 in cervical cancer have not been further reported. In the present study, we analyzed the expression of miR-494 in -with PTEN expression and clinicopathological data of cervical cancer patients. The results showed that miR-494 expression was significantly upregulated in human cervical cancer cell lines and tissues. miR-494 upregulation was significantly associated with PTEN downregulation, adverse clinicopathological characteristics, poor overall and progression-free survival and poor prognosis. In vitro experiments showed that inhibition of miR-494 suppressed cell proliferation and growth by directly targeting the 3'-untranslated region (3'-UTR) of PTEN mRNA. These findings identified a novel molecular mechanism involved in the regulation of PTEN expression and cervical cancer progression. Results of the present study indicated that miR-494 may have an essential role in the carcinogenesis and progression of cervical cancer and targeting miR-494 may be a promising therapeutic strategy for the treatment of cervical cancer.

miR-135a modulates tendon stem/progenitor cell senescence via suppressing ROCK1

Tendon stem/progenitor cell (TSPC) senescence may lead to age-related tendon disorders and impair tendon regeneration and replacement capacity in humans. However, the mechanisms governing TSPC aging and degeneration remain obscure. Recently, it has been reported that Rho-associated coiled-coil protein kinase 1 (ROCK1) might be a key player in TSPC aging process. miRNAs are also involved in cellular senescence. In this study, whether miRNAs modulate senescence of TSPCs through targeting ROCK1 was evaluated. We found that miR-135a, which directly binds to the 3'-untranslated region of ROCK1, is significantly downregulated in aged compared with young TSPCs. Overexpression of miR-135a in young TSPCs suppresses senescence, promotes proliferation, and induces migration and tenogenic differentiation, whereas suppression of miR-135a in aged TSPCs has the opposite effects. By gain-of-function and loss-of-function studies, we confirmed that ROCK1 mediates the effects of miR-135a in TSPCs. Taken together, our data suggest that miR-135a plays an important role in TSPC senescence via targeting ROCK1.

Involvement of seven in absentia homolog-1 in ethanol-induced apoptosis in neural crest cells

Ethanol-induced apoptosis in selected cell populations is a major component of pathogenesis underlying ethanol-induced teratogenesis. However, there is a fundamental gap in understanding how ethanol leads to apoptosis in embryos. In this study, we investigate the role of seven in absentia homolog-1 (Siah1) protein, an E3 ubiquitin ligase, in ethanol-induced apoptosis. Using an in vitro model of neural crest cell (NCC), JoMa1.3 cells, we found that exposure to 100mM ethanol resulted in a significant increase in Siah1 mRNA expression in NCCs, an ethanol-sensitive cell population implicated in Fetal Alcohol Spectrum Disorders (FASD). Treatment with 100mM ethanol for 24h also significantly increased the protein expression of Siah1 in JoMa1.3 cells. The nuclear translocation and accumulation of Siah1 was evidenced in the cells exposed to ethanol. In addition, we have found that the inhibition of Siah1 function with siRNA prevents ethanol-induced increase in Siah1 protein expression and nuclear translocation in NCCs. Down-regulation of Siah1 by siRNA also greatly diminished ethanol-induced cell death and caspase-3 activation, indicating that inhibition of Siah1 can attenuate ethanol-induced apoptosis. These results strongly suggest that Siah1 plays an important role in ethanol-induced apoptosis in NCCs.

Androgen-regulated microRNA-135a decreases prostate cancer cell migration and invasion through downregulating ROCK1 and ROCK2

Androgen signaling, via the androgen receptor (AR), is crucial in mediating prostate cancer (PCa) initiation and progression. Identifying new downstream effectors of the androgens/AR pathway will allow a better understanding of these mechanisms and could reveal novel biomarkers and/or therapeutic agents to improve the rate of patient survival. We compared the microRNA expression profiles in androgen-sensitive LNCaP cells stimulated or not with 1 nM R1881 by performing a high-throughput reverse transcriptase-quantitative PCR and found that miR-135a was upregulated. After androgen stimulation, we showed that AR directly activates the transcription of miR-135a2 gene by binding to an androgen response element in the promoter region. Our findings identify miR-135a as a novel effector in androgens/AR signaling. Using xenograft experiments in chick embryos and adult male mice, we showed that miR-135a overexpression decreases in vivo invasion abilities of prostate PC-3 cells. Through in vitro wound-healing migration and invasion assays, we demonstrated that this effect is mediated through downregulating ROCK1 and ROCK2 expression, two genes that we characterized as miR-135a direct target genes. In human surgical samples from prostatectomy, we observed that miR-135a expression was lower in tumoral compared with paired adjacent normal tissues, mainly in tumors classified with a high Gleason score (⩾8). Moreover, miR-135a expression is lower in invasive tumors, showing extraprostatic extension, as compared with intraprostatic localized tumors. In tumor relative to normal glands, we also showed a more frequently higher ROCK1 protein expression determined using a semi-quantitative immunohistochemistry analysis. Therefore, in tumor cells, the lower miR-135a expression could lead to a higher ROCK1 protein expression, which could explain their invasion abilities. The highlighted relationship between miR-135a expression level and the degree of disease aggressiveness suggests that miR-135a may be considered as a prognostic marker in human PCa.