MiR-202 inhibits the proliferation and invasion of colorectal cancer by targeting UHRF1

miRNAs: possible regulators of toll like receptors and inflammatory tumor microenvironment in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is ranked as the third most commonly diagnosed cancer and the third cause of cancer related deaths. CRC is greatly attributed to genetic and epigenetic mutations and immune dysregulation. Tumor aberrant expression of Toll-like Receptors (TLRs) can contribute to tumorigenesis. Recent studies suggested that microRNAs act as direct ligands of TLRs altering their expression and signaling pathways.

AIM

To prove our concept that specific miRNA mimics may act as antagonists of their specific toll like receptors inhibiting their expression that could limit the release of pro-inflammatory and pro-tumorigenic cytokines leading to apoptosis of tumor cells.

METHODS

From public microarray databases, we retrieved TLRs and miRNAs related to CRC followed by in silico docking of the selected miRNA ligands into the TLRs. Clinical validation after co-immunoprecipitation of TLRs and their interacting miRNA ligands was done. Expression of TLRs 1, 7,8 was determined by ELISA while miRNAs was measured by RT-qPCR. In addition, microRNA mimics of the down regulated miRNAs were transfected into human CRC cell lines.

RESULTS

Our data demonstrate that TLRs 1, 7, 8 are up regulated in CRC compared to controls. Further, three miRNAs (-122, -29b and -15b) are relatively downregulated, while 4 miRNAs (-202, miRNA-98, -21 and -let7i) are upregulated in CRC patients compared to those with benign tumor and healthy controls. Transfection of down regulated miRNA mimics into CRC cell lines resulted in a significant reduction of the number and viability of cells as well as down regulating the expression of TLRs 1, 7 and 8 with ultimate reduction of downstream effector IL6 protein, suggesting that these miRNAs are negative regulators of carcinogenesis.

CONCLUSION

MicroRNAs could act as antagonistic ligands of TLRs limiting the inflammatory tumor microenvironment.

UHRF1 shapes both the trophoblast invasion and decidual macrophage differentiation in early pregnancy

Trophoblasts play critical roles in establishment and maintenance of a normal pregnancy. Their dysfunction in early pregnancy is closely related to pregnancy-related diseases, including recurrent pregnancy loss (RPL). Epigenetic modifications dynamically change during pregnancy; however, the role of the epigenetic modifier UHRF1 in trophoblast regulation remains unknown. This is the first study to show that UHRF1 expression was localized in the cytoplasm of cytotrophoblasts, syncytiotrophoblasts, and villi columns, and decreased in the villi of patients with RPL. The invasion and cell viability in a UHRF1 knockdown trophoblast cell line were significantly decreased. In addition, the mRNA expression profiles of Swan71 cells were partially altered by UHRF1 knockdown. The altered immune-related genes were screened out and the pro-inflammatory TH1-type chemokine/cytokines CXCL2 and IL-1β were identified as the most promising targets of UHRF1 in the trophoblasts, which were significantly increased in the UHRF1 knockdown Swan71 cells, villi, and serum from patients with RPL. The macrophages treated with the supernatants of UHRF1 knockdown Swan71 cells were polarized to the M1 phenotype and secreted high levels of pro-inflammatory cytokines, which might be driven by the activated MyD88/NF-κB signaling pathway and mediated by the increased expression of CXCR2 and IL-1R1 (CXCL2 and IL-1β receptors, respectively). In addition, the supernatants of UHRF1 knockdown Swan71 cells showed stronger chemotaxis to macrophages than those from the controls. Our findings highlight the previously unknown roles of UHRF1 as one of the key regulators on the trophoblasts and their cross-talk with local immune cells, and demonstrate a potential approach for RPL intervention.

Epi-miRNAs: Regulators of the Histone Modification Machinery in Human Cancer

Cancer is a leading cause of death and disability worldwide. Epigenetic deregulation is one of the most critical mechanisms in carcinogenesis and can be classified into effects on DNA methylation and histone modification. MicroRNAs are small noncoding RNAs involved in fine-tuning their target genes after transcription. Various microRNAs control the expression of histone modifiers and are involved in a variety of cancers. Therefore, overexpression or downregulation of microRNAs can alter cell fate and cause malignancies. In this review, we discuss the role of microRNAs in regulating the histone modification machinery in various cancers, with a focus on the histone-modifying enzymes such as acetylases, deacetylases, methyltransferases, demethylases, kinases, phosphatases, desumoylases, ubiquitinases, and deubiquitinases. Understanding of microRNA-related aberrations underlying histone modifiers in pathogenesis of different cancers can help identify novel therapeutic targets or early detection approaches that allow better management of patients or monitoring of treatment response.

LncRNA LINC00342 contributes to the growth and metastasis of colorectal cancer via targeting miR-19a-3p/NPEPL1 axis

Background

Long intergenic non-protein coding RNA 00342 (LINC00342) has been identified as a novel oncogene. However, the functional role of LINC00342 in colorectal cancer (CRC) remains unclear.

Methods

The expression of LINC00342 is detected by real-time PCR (RT-PCR) analysis. Cell proliferation, migration and invasion and xenograft model are examined to analyze the biological functions of LINC00342 in vitro and in vivo using colony formation, would healing and transwell analyses. Dual-luciferase reporter and RNA immunoprecipitation (RIP) assays are used to identify the target interactions between LINC00342, miR-19a-3p and aminopeptidase like 1 (NPEPL1).

Results

LINC00342 was highly expressed in CRC. Down-regulation of LINC00342 inhibited cell proliferation and metastasis of CRC cells. Moreover, knocking down LINC00342 inhibited the tumor growth in vivo. Mechanistic investigation revealed that LINC00342 might sponge miR-19a-3p to regulate NPEPL1 expression. Further investigation indicated that the ontogenesis facilitated by LINC00342 was inhibited due to the depletion of NPEPL1.

Conclusion

LINC00342 promotes CRC progression by competitively binding miR-19a-3p with NPEPL1.

MicroRNA‑202 inhibits endometrial stromal cell migration and invasion by suppressing the K‑Ras/Raf1/MEK/ERK signaling pathway

The enhanced migratory ability of endometrial stromal cells (ESCs) is a key factor in the formation of functional endometrium‑like tissues outside the uterine cavity during endometriosis (EMS). Although accumulating evidence has suggested the importance of microRNAs (miRNAs) in the pathogenesis of EMS, the role of particular miRNAs in the invasiveness of ESCs remain poorly understood. In the present study, the function of miRNAs in the invasiveness of ESCs, along with the associated underlying mechanism involved, were investigated. Initially, the expression patterns of miRNAs in the ectopic and eutopic endometrium isolated from patients with EMS were analyzed using microarray. MicroRNA‑202‑5p (miR‑202) was selected for further study due to its previously reported suppressive effects on the invasion in various types of cancers. The expression of miR‑202 and K‑Ras in eutopic and ectopic endometrioma tissues were detected using reverse transcription‑quantitative PCR, immunohistochemistry and western blotting. The migration and invasion ability of ESCs was determined using wound healing and Transwell invasion assays, respectively. Compared with that from healthy individuals, miR‑202 expression was demonstrated to be lower in the eutopic endometrium from patients with EMS, which was even lower in ectopic endometrium. Functional experiments in primary ESCs revealed that enhanced miR‑202 expression suppressed the cell invasion and migration abilities, which was also accompanied with increased E‑cadherin and reduced N‑cadherin expression in ESCs, suggesting its potentially suppressive role in epithelial‑mesenchymal transition. K‑Ras is a well‑known regulator of the ERK signaling pathway that was shown to be directly targeted and negatively regulated by miR‑202. In addition, K‑Ras expression was found to be upregulated in the ectopic endometrium, where it correlated negatively with that of miR‑202. Knocking down K‑Ras expression mimicked the anti‑invasive effects of miR‑202 overexpression on ESCs, whilst K‑Ras overexpression attenuated the inhibitory role of miR‑202 overexpression in ESC invasion. The K‑Ras/Raf1/MEK/ERK signaling pathway was also blocked by miR‑202 overexpression. These findings suggested that miR‑202 inhibited ESC migration and invasion by inhibiting the K‑Ras/Raf1/MEK/ERK signaling pathway, rendering miR‑202 a candidate for being a therapeutic target for EMS.

Silencing miR-202-3p increases MMP-1 and promotes a brain invasive phenotype in metastatic breast cancer cells

BACKGROUND

Brain metastasis (BM) is a major cause of morbidity and mortality in breast cancer (BC) and its molecular mechanism remains poorly understood. Transmigration of metastatic cells through the brain endothelium is an essential step in BM. Metalloproteinase-1 (MMP-1) overexpression plays a key role in promoting trans-endothelial migration by degrading the inter-endothelial junctions and disrupting the endothelial integrity. However, little is known about the molecular mechanisms that induce MMP-1 in metastatic cells granting them a brain invasive phenotype. MiR-202-3p is downregulated in brain metastases compared to primary breast tumors and directly targets MMP-1. Here, we unraveled a critical role of miR-202-3p loss in MMP-1 upregulation promoting transmigration of metastatic cells through the brain endothelium.

METHODS

A variant of the MDA-MB-231 human BC cell line (MDA-MB-231-BrM2) selected for its propensity to form brain metastases was found to express high levels of MMP-1 and low levels of miR-202-3p compared to the parental cells. Using a gain-and-loss of function approach, we modulated levels of miR-202-3p and examined the resultant effect on MMP-1 expression. Effect of miR-202-3p modulation on integrity of the brain endothelium and the transmigrative ability of BC cells were also examined.

RESULTS

Loss of miR-202-3p in breast cancer cells enhanced their transmigration through the brain endothelium by upregulating MMP-1 and disrupting the inter-endothelial junctions (claudin-5, ZO-1 and ß-catenin). Restoring miR-202-3p exerted a metastasis-suppressive effect and preserved the endothelial barrier integrity.

CONCLUSIONS

Our study identified a critical regulatory role of miR-202-3p in brain metastasis and shed light on miR-202-3p/MMP-1 axis as a novel prognostic and therapeutic target that can be exploited to predict and prevent brain metastasis in breast cancer patients.

Regulation of DNA methylation machinery by epi-miRNAs in human cancer: emerging new targets in cancer therapy

Disruption in DNA methylation processes can lead to alteration in gene expression and function that would ultimately result in malignant transformation. In this way, studies have shown that, in cancers, methylation-associated silencing inactivates tumor suppressor genes, as effectively as mutations. DNA methylation machinery is composed of several genes, including those with DNA methyltransferases activity, proteins that bind to methylated cytosine in the promoter region, and enzymes with demethylase activity. Based on a prominent body of evidence, DNA methylation machinery could be regulated by microRNAs (miRNAs) called epi-miRNAs. Numerous studies demonstrated that dysregulation in DNA methylation regulators like upstream epi-miRNAs is indispensable for carcinogenesis; consequently, the malignant capacity of these cells could be reversed by restoring of this regulatory system in cancer. Conceivably, recognition of these epi-miRNAs in cancer cells could not only reveal novel molecular entities in carcinogenesis, but also render promising targets for cancer therapy. In this review, at first, we have an overview of the methylation alteration in cancers, and the effect of this phenomenon in miRNAs expression and after that, we conduct an in-depth discussion about the regulation of DNA methylation regulators by epi-miRNAs in cancer cells.

Silencing UHRF1 enhances cell autophagy to prevent articular chondrocytes from apoptosis in osteoarthritis through PI3K/AKT/mTOR signaling pathway

Osteoarthritis (OA) is a common chronic degenerative joint disease, and chondrocyte apoptosis is one of most important pathological changes of OA pathogenesis. Growing studies have shown that Ubiquitin-like with PHD and RING finger domains 1 (UHRF1) is an important epigenetic regulatory factor that regulates cell proliferation and apoptosis of various tumors, but its role in OA remains ill-defined. In the present study, we found that UHRF1 expression was increased in human OA cartilage tissues, compared with normal cartilage tissues. Interleukin-1β (IL-1β), a major inflammatory cytokine that promotes cartilage degradation in OA, was used to stimulate primary human chondrocytes in vitro. The expression of UHRF1 was also enhanced in IL-1β-induced chondrocytes. Moreover, down-regulation of UHRF1 induced an increase on cell proliferation and autophagy, and a decrease on apoptosis of chondrocytes after IL-1β treatment. Further data indicated that silencing UHRF1 attenuated the up-regulation of IL-1β on phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway in chondrocytes. Then, an activator of PI3K weakened the effect of UHRF1 silencing on cell proliferation, autophagy, apoptosis of IL-1β-induced chondrocytes, and the cell autophagy special inhibitor 3-methyladenine (3-MA) also showed a same impact on UHRF1, hence suggesting that knockdown of UHRF1 enhances cell autophagy to protect chondrocytes from apoptosis in OA through PI3K/AKT/mTOR signaling pathway. In conclusion, our study suggests that UHRF1 may be a potential regulator of chondrocyte apoptosis in the pathogenesis of OA.

Diagnostic Value of Circulating miR-202 in Early-Stage Breast Cancer in South Korea

Background and objectives: Breast cancer is the most common cancer among women worldwide. Early stage diagnosis is important for predicting increases in treatment success rates and decreases in patient mortality. Recently, circulating biomarkers such as circulating tumor cells, circulating tumor DNA, exosomes, and circulating microRNAs have been examined as blood-based markers for the diagnosis of breast cancer. Although miR-202 has been studied for its function or expression in breast cancer, its potential diagnostic value in a clinical setting remains elusive and miR-202 has not been investigated in South Korea. In this study, we aimed to evaluate the diagnostic utility of miR-202 in plasma samples of breast cancer patients in South Korea. Materials and Methods: We investigated miR-202 expression in the plasma of 30 breast cancer patients during diagnosis along with 30 healthy controls in South Korea by quantitative reverse transcription PCR. Results: The results showed that circulating miR-202 levels were significantly elevated in the breast cancer patients compared with those in healthy controls (p < 0.001). The sensitivity and specificity of circulating miR-202 were 90.0% and 93.0%, respectively. Additionally, circulating miR-202 showed high positivity at early stage. The positive rate of miR-202 was as follows: 100% (10/10) for stage I, 90% (9/10) for stage II, and 80% (8/10) for stage III. miR-202 was also a predictor of a 9.6-fold high risk for breast cancer (p < 0.001). Conclusions: Additional alternative molecular biomarkers for diagnosis and management of pre-cancer patients are needed. Circulating miR-202 might be potential diagnostic tool for detecting early stage breast cancer.

MiR-506 Targets UHRF1 to Inhibit Colorectal Cancer Proliferation and Invasion via the KISS1/PI3K/NF-κB Signaling Axis

Background

The UHRF1 gene is an epigenetic modification factor that mediates tumor suppressor gene silencing in a variety of cancers. Related studies have reported that UHRF1 can inhibit the expression of the KISS1 gene. However, the regulatory mechanism underlying UHRF1 expression in colorectal cancer (CRC) is still unclear. The aim of this study was to gain a better understanding of the regulation of UHRF1 expression in CRC and to determine whether it regulates the mechanism by which KISS1 promotes CRC metastasis.

Methods

In the present study, the levels of miR-506, UHRF1 and KISS1 expression in CRC tissues and in human CRC cell lines were studied using quantitative real-time PCR (qRT-PCR) and Western blotting. Cell proliferation, migration, and invasion assays are used to detect cell proliferation, migration, and invasion. A dual-luciferase reporter system was used to confirm the target gene of miR-506.

Results

This study found that UHRF1 protein is highly expressed in CRC tissues and negatively correlated with KISS1 protein expression. UHRF1 overexpression activates the PI3K/NF-κB signaling pathway by inhibiting the mRNA expression levels of pathway mediators. Bioinformatics analysis and luciferase reporter gene assays confirmed that miR-506 targets UHRF1.

Conclusion

This study identified the regulation of UHRF1 expression in CRC and the mechanism of CRC metastasis. UHRF1 may be a new potential target molecule for future CRC metastasis treatment.