miR‑377 targets CUL4A and regulates metastatic capability in ovarian cancer

Inhibitory effect of miR-377 on the proliferative and invasive behaviors of prostate cancer cells through the modulation of MYC mRNA via its interaction with BCL-2/Bax, PTEN, and CDK4

The MYC gene is a regulatory and proto-oncogenic gene that is overexpressed in the majority of prostate cancers (PCa). Numerous studies have indicated that aberrant expression of microRNAs is involved in the initiation and progression of prostate cancer. In this investigation, we assessed the impact of miR-377 on MYC through luciferase assay. Real-time PCR was employed to determine whether miR-377 could reduce the levels of MYC mRNA in transfected PCa cell lines (PC-3 and DU145) and change in the mRNA levels of BCL-2/Bax, PTEN, and CDK4 as a consequence of MYC downregulation. Moreover, we analyzed the effects of miR-377 on apoptosis, proliferation, cell cycle, and wound healing. Our findings demonstrate that miR-377 effectively targets MYC mRNA, as confirmed by luciferase assay and Real-time PCR. We observed a significant reduction in BCL-2 and CDK4 expression, along with an increase in Bax and PTEN, in prostate cancer cell lines upon MYC suppression. Additionally, elevated levels of miR-377 in PCa cell lines induced apoptosis, inhibited proliferation and migration, and arrested the cell cycle. Taken together, these results unveil the inhibitory role of miR-377 in MYC function within PCa, thereby suggesting its potential as a therapeutic target for the treatment of this malignancy.

Extracellular Vesicles-ceRNAs as Ovarian Cancer Biomarkers: Looking into circRNA-miRNA-mRNA Code

Simple Summary

Patients with ovarian cancer have a very poor chance of long-term survival, usually due to advanced disease at the time of diagnosis. Emerging evidence suggests that extracellular vesicles contain noncoding RNAs such as microRNAs, piwiRNAs, circular RNAs, and long noncoding RNAs, with regulatory effects on ovarian cancer. In this review, we focus on ovarian cancer-associated circular RNA shuttled by extracellular vesicles as mediators of cancer progression and novel biomarkers in liquid biopsy. We propose a circular-RNA–microRNA-mRNA code that can reveal the regulatory network created by extracellular vesicles, noncoding RNAs, and mRNAs in ovarian cancer. Future research in this field will help to identify novel diagnostic biomarkers and druggable therapeutic targets, which will ultimately benefit patients.

Abstract

Ovarian cancer (OC) is one of the most lethal gynecologic malignancies in females worldwide. OC is frequently diagnosed at an advanced stage due to a lack of specific symptoms and effective screening tests, resulting in a poor prognosis for patients. Age, genetic alterations, and family history are the major risk factors for OC pathogenesis. Understanding the molecular mechanisms underlying OC progression, identifying new biomarkers for early detection, and discovering potential targets for new drugs are urgent needs. Liquid biopsy (LB), used for cancer detection and management, consists of a minimally invasive approach and practical alternative source to investigate tumor alterations by testing extracellular vesicles (EVs), circulating tumor cells, tumor-educated platelets, and cell-free nucleic acids. EVs are nanosize vesicles shuttling proteins, lipids, and nucleic acids, such as DNA, RNA, and non-coding RNAs (ncRNAs), that can induce phenotypic reprogramming of target cells. EVs are natural intercellular shuttles for ncRNAs, such as microRNAs (miRNAs) and circular-RNAs (circRNAs), known to have regulatory effects in OC. Here we focus on the involvement of circRNAs and miRNAs in OC cancer progression. The circRNA-microRNA-mRNA axis has been investigated with Circbank and miRwalk analysis, unraveling the intricate and detailed regulatory network created by EVs, ncRNAs, and mRNAs in OC.

miR-377 Inhibits Proliferation and Differentiation of Bovine Skeletal Muscle Satellite Cells by Targeting FHL2

Non-coding RNAs, especially microRNAs (miRNAs), play an important role in skeletal muscle growth and development. miR-377 regulates many basic biological processes and plays a key role in tumor cell proliferation, migration and apoptosis. Nevertheless, the function of miR-377 during skeletal muscle development and how it regulates skeletal muscle satellite cells (SMSCs) remains unclear. In the present study, we proposed to elucidate the regulatory mechanism of miR-377 in the proliferation and differentiation of bovine primary SMSCs. Our results showed that miR-377 can significantly inhibit the proliferation of SMSCs. In addition, we found that miR-377 can reduce myotube formation and restrain skeletal myogenic differentiation. Moreover, the results obtained from the biosynthesis and dual luciferase experiments showed that FHL2 was the target gene of miR-377. We further probed the function of FHL2 in muscle development and found that FHL2 silencing significantly suppressed the proliferation and differentiation of SMSCS, which is contrary to the role of miR-377. Furthermore, FHL2 interacts with Dishevelled-2 (Dvl2) to enable Wnt/β-catenin signaling pathway, consequently regulating skeletal muscle development. miR-377 negatively regulates the Wnt/β-catenin signaling pathway by targeting FHL2-mediated Dvl2. Overall, these findings demonstrated that miR-377 regulates the bovine SMSCs proliferation and differentiation by targeting FHL2 and attenuating the Wnt/β-catenin signaling pathway.

The role of miRNA-377 as a tumor suppressor in lung cancer by negative regulation of genes belonging to ErbB signaling pathway

BACKGROUND

The ErbB signaling pathway plays important role in the pathogenesis of lung cancer. We explored the role of miRNA-377 as a tumor suppressor in NSCLC through silencing of some genes in the ErbB pathway.

METHODS AND RESULTS

The targeting effect of miRNA-377 on EGFR, MAPK1, ABL2, and PAK2 was evaluated. The expression levels of these genes and miRNA-377 were surveyed in NSCLC and normal human tissues, Calu-6, and A549 cells. Real-time PCR was used to figure out whether miRNA-377 could decrease the target genes mRNAs in transfected lung cancer cell lines. The effects of miRNA-377 on apoptosis cell and proliferation were analyzed. We showed that miRNA-377 targets EGFR, MAPK1, and PAK2 mRNAs in in-silico and luciferase reporter assay. The expression of miRNA-377 was significantly downregulated in human NSCLC tissues, Calu-6 and A549 cells compared to their controls. We observed a negative correlation between EGFR, MAPK1, PAK2, and miRNA-377 expression in human NSCLC tissues. A significant reduction in EGFR, MAPK1, and PAK2 mRNA levels was detected, following miRNA-377 transfection in Calu-6 and A549 cells. The higher levels of miRNA-377 in Calu-6, and A549 cells induced apoptosis and reduced proliferation, significantly.

CONCLUSIONS

All these data reveal that miRNA-377 functions as a tumor suppressor in NSCLC and may serve as a potential therapeutic target for the treatment of NSCLC.

microRNA-377-3p inhibits osteosarcoma progression by targeting CUL1 and regulating Wnt/β-catenin signaling pathway

OBJECTIVE

Emerging studies highlight the crucial effects of microRNAs on cancer initiation and malignant progression of various tumors. This study focused on the biological effect of miR-377-3p on CUL1 and epithelial-mesenchymal transition (EMT) and Wnt/β-catenin pathways in osteosarcoma (OS).

METHODS

We performed quantitative real-time polymerase chain reaction (qRT-PCR) to analyze miR-377-3p and CUL1 expression levels in OS tissues and MG-63 cells. Then, cell counting kit (CCK)-8 and Transwell assay were used to examine the functions of miR-377-3p in OS cell growth and metastasis abilities. Meanwhile, luciferase reporter assay was used to validate CUL1 as direct target of miR-377-3p. qRT-PCR and Western blot were then carried out to detect the impact of miR-377-3p on EMT and Wnt/β-catenin pathways. Tumor xenograft models were established to further examine the effects of miR-377-3p on OS tumorigenesis in vivo.

RESULTS

miR-377-3p downregulation was frequently identified in OS tissues and cells, which was associated with worse prognosis of OS patients. Functional experiments showed miR-377-3p restoration could dramatically repress OS cell growth and migration by regulation of EMT and Wnt/β-catenin pathways. Moreover, luciferase reporter assay revealed that CUL1 acted as a functional target of miR-377-3p. Additionally, the elevated CUL1 expressions in OS tissues also indicated poor prognosis of OS patients. Furthermore, the OS tumor growth was also obviously inhibited by miR-377-3p overexpression in vivo.

CONCLUSIONS

Collectively, all the above findings revealed that miR-377-3p exerted anti-OS functions via CUL1 and EMT and Wnt/β-catenin pathways. These results may contribute to the development of clinical OS treatment.

Autophagy Plays a Role in the CUL4A-Related Poor Prognosis of Intrahepatic Cholangiocarcinoma

CUL4A regulate the termination of autophagy in a physical process. However, the relationship between CUL4A and autophagy in cancer is unclear. We retrospectively investigated 99 intrahepatic cholangiocarcinoma (iCCA) cases. Whole sections were used for immunohistochemical analysis for p62, and LC3B expression. Q-score was defined as the sum of the labeling intensity and proportion. The cut-off point for immunoreactivity was set. CUL4A was overexpressed in cell lines and autophagy reflux was compared after manipulation. The iCCA cases with CUL4A overexpression had significantly higher prevalence of intact activated autophagy (42.4 vs. 15.2%; p = 0.003), which was significantly associated with advance tumor stage (34.1% vs. 15.4%; p = 0.032), less extensive necrosis (8.3 vs. 49.3%; p < 0.001), and shortened disease-free survival (mean, 19.6 vs. 65.5 months, p = 0.015). In vitro, iCCA cells with CUL4A overexpression significantly increased LC3II level as compared to the cells under basal condition. Although both cell types showed intact autophagy with increased LC3II expression after bafilomycin A1 treatment, the accumulation of LC3II was higher in CUL4A-overexpressing cells. CUL4A overexpression increased the proliferation of cells as compared with control cells. After treatment with bafilomycin A1, proliferation was inhibited in both cell types, but the effects were more prominent in the cells overexpressing CUL4A. CUL4A promotes autophagy, and exhibits significantly higher autophagic flux which affects the proliferation of iCCA cells; these effects correlated with advance tumor stage and poor prognosis. Thus, targeting autophagy may be potentially therapeutic in iCCA.

CircAGAP1 promotes tumor progression by sponging miR-15-5p in clear cell renal cell carcinoma

Background

Accumulating evidence has revealed that circular RNAs (circRNAs), as novel noncoding RNAs, play critical roles in carcinogenesis and tumor progression. However, the functions and molecular mechanisms of circRNAs in clear cell renal cell carcinoma (ccRCC) are largely unknown.

Methods

The expression and functions of circAGAP1 were identified in clinical samples, ccRCC cells and in vivo animal models. The molecular mechanism of circAGAP1 was investigated by fluorescence in situ hybridization, RNA immunoprecipitation and luciferase assays.

Results

circAGAP1 (circ0058792) expression was significantly upregulated in ccRCC tissues compared to adjacent nontumor tissues. Moreover, the expression of circAGAP1 was closely related to the tumor size, nuclear grade and clinical stage of ccRCC in patients. Mechanistic studies demonstrated that cytoplasmic circAGAP1 targeted miR-15-5p in an RNA-induced silencing complex. Additionally, miR-15-5p expression was downregulated in ccRCC. Luciferase reporter assays showed that E2F transcription factor 3 (E2F3) was a target of miR-15-5p, and upregulated E2F3 expression was positively correlated with circAGAP1 in ccRCC. Furthermore, the tumor-promoting functions of circAGAP1 could be alleviated by miR-15-5p mimics in vitro and in vivo.

Conclusion

Our results clarify that circAGAP1 exerts its oncogenic functions as a competitive endogenous RNA (ceRNA) by sponging miR-15-5p, which promotes E2F3 expression. Targeting circAGAP1 might be a new attractive therapeutic strategy in ccRCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01864-3.

CUL4A regulates endometrial cancer cell proliferation, invasion and migration by interacting with CSN6

Endometrial cancer (EC) is a common malignant gynecological tumor arising from the endometrium, with an annually increasing morbidity and mortality. The present study aimed to investigate the functions of cullin 4A (CUL4A) in EC, as well as the underlying mechanisms. CUL4A expression was assessed in several human EC cells and normal human endometrial epithelial cells (hEECs) via reverse transcription‑quantitative polymerase chain reaction and western blotting. Subsequently, short hairpin (sh)RNA‑CULA4 was transfected into cells, and cell proliferation, invasion and migration were detected using Cell Counting kit‑8, Transwell and wound healing assays, respectively. The STRING database identified that CSN6 interacted with CULA4, and immunoprecipitation was performed to verify the interaction. Subsequently, following CUL4A knockdown, pcDNA3.1‑CSN6 was transfected into cells and its effects on cell proliferation, invasion and migration were assessed. The expression levels of matrix metallopeptidase (MMP)2, MMP9 and p53 were evaluated via western blotting. The results indicated that CUL4A was highly expressed in EC cells, compared with hEECs. CULA4‑knockdown notably inhibited EC cell proliferation, invasion and migration. The expression levels of MMP2 and MMP9 were significantly decreased, while p53 expression was enhanced following CUL4A‑knockdown. The immunoprecipitation assay verified that COP9 signalosome subunit 6 (CSN6) interacted with CULA4. Furthermore, CSN6‑overexpression alleviated the inhibitory effects of CUL4A‑knockdown on EC cell proliferation, invasion and migration. Similarly, CSN6 overexpression reversed CUL4A‑knockdown‑mediated effects on the expression of MMP2, MMP9 and p53. In summary, the results demonstrated that CUL4A regulated EC cell proliferation, invasion and migration by interacting with CSN6.

The Role of microRNAs in Epithelial Ovarian Cancer Metastasis

Epithelial ovarian cancer (EOC) is the deadliest gynecological cancer, and the major cause of death is mainly attributed to metastasis. MicroRNAs (miRNAs) are a group of small non-coding RNAs that exert important regulatory functions in many biological processes through their effects on regulating gene expression. In most cases, miRNAs interact with the 3′ UTRs of target mRNAs to induce their degradation and suppress their translation. Aberrant expression of miRNAs has been detected in EOC tumors and/or the biological fluids of EOC patients. Such dysregulation occurs as the result of alterations in DNA copy numbers, epigenetic regulation, and miRNA biogenesis. Many studies have demonstrated that miRNAs can promote or suppress events related to EOC metastasis, such as cell migration, invasion, epithelial-to-mesenchymal transition, and interaction with the tumor microenvironment. In this review, we provide a brief overview of miRNA biogenesis and highlight some key events and regulations related to EOC metastasis. We summarize current knowledge on how miRNAs are dysregulated, focusing on those that have been reported to regulate metastasis. Furthermore, we discuss the role of miRNAs in promoting and inhibiting EOC metastasis. Finally, we point out some limitations of current findings and suggest future research directions in the field.

MicroRNAs target the Wnt/β‑catenin signaling pathway to regulate epithelial‑mesenchymal transition in cancer (Review)

Epithelial‑mesenchymal transition (EMT), during which cancer cells lose the epithelial phenotype and gain the mesenchymal phenotype, has been verified to result in tumor migration and invasion. Numerous studies have shown that dysregulation of the Wnt/β‑catenin signaling pathway gives rise to EMT, which is characterized by nuclear translocation of β‑catenin and E‑cadherin suppression. Wnt/β‑catenin signaling was confirmed to be affected by microRNAs (miRNAs), several of which are down‑ or upregulated in metastatic cancer cells, indicating their complex roles in Wnt/β‑catenin signaling. In this review, we demonstrated the targets of various miRNAs in altering Wnt/β‑catenin signaling to promote or inhibit EMT, which may elucidate the underlying mechanism of EMT regulation by miRNAs and provide evidence for potential therapeutic targets in the treatment of invasive tumors.

Wnt/β-catenin signalling in ovarian cancer: Insights into its hyperactivation and function in tumorigenesis

Epithelial ovarian cancer (EOC) is the deadliest female malignancy. The Wnt/β-catenin pathway plays critical roles in regulating embryonic development and physiological processes. This pathway is tightly regulated to ensure its proper activity. In the absence of Wnt ligands, β-catenin is degraded by a destruction complex. When the pathway is stimulated by a Wnt ligand, β-catenin dissociates from the destruction complex and translocates into the nucleus where it interacts with TCF/LEF transcription factors to regulate target gene expression. Aberrant activation of this pathway, which leads to the hyperactivity of β-catenin, has been reported in ovarian cancer. Specifically, mutations of CTNNB1, AXIN, or APC, have been observed in the endometrioid and mucinous subtypes of EOC. In addition, upregulation of the ligands, abnormal activation of the receptors or intracellular mediators, disruption of the β-catenin destruction complex, inhibition of the association of β-catenin/E-cadherin on the cell membrane, and aberrant promotion of the β-catenin/TCF transcriptional activity, have all been reported in EOC, especially in the high grade serous subtype. Furthermore, several non-coding RNAs have been shown to regulate EOC development, in part, through the modulation of Wnt/β-catenin signalling. The Wnt/β-catenin pathway has been reported to promote cancer stem cell self-renewal, metastasis, and chemoresistance in all subtypes of EOC. Emerging evidence also suggests that the pathway induces ovarian tumor angiogenesis and immune evasion. Taken together, these studies demonstrate that the Wnt/β-catenin pathway plays critical roles in EOC development and is a strong candidate for the development of targeted therapies.

Upregulation of CENPM promotes hepatocarcinogenesis through mutiple mechanisms

Background

Hepatocellular carcinoma (HCC) still remains a dominating medical challenge in early diagnosis and clinical therapy. Centromere protein M (CENPM) has been proved to be over-expressed in HCC tissues, but carcinogenic mechanism of CENPM contributing to liver cancer is poorly understood.

Methods

In this study, we first explored mRNA and protein levels of CENPM in HCC samples, matching adjacent non-tumor tissues and six hepatoma cell lines by polymerase chain reaction (PCR), western blotting and immunohistochemistry (IHC). Clinical data of HCC patients downloaded from The Cancer Genome Atlas (TCGA) were also analyzed. The character of CENPM concerned with HCC progression through several functional experimentations in vitro and in vivo was researched. Bioinformatics was carried out to further discover biological functions of CENPM.

Results

CENPM was positively up-regulated in HCC and connected with a poor prognosis. Silencing CENPM repressed cell proliferation in vivo and in vitro, and knock-down CENPM inhibited cell migration and invasion. Additionally, depletion of CENPM can promote cell apoptosis and arrested cell cycle. Furthermore, single-gene gene set enrichment analysis (GSEA) analysis indicated that CENPM was linked to the P53 signaling pathway and cell cycle pathway, and our research supported this prediction. Finally, we also found that miR-1270 was a negative regulator and participated in post-transcriptional regulation of CENPM, and hepatitis B virus X protein (HBx) can promote hepatocellular carcinoma by suppressing miR1270.

Conclusion

CENPM was closely associated with HCC progression and it could be considered as a new possible biomarker along with a therapeutic target for HCC.

Small molecule TSC01682 inhibits osteosarcoma cell growth by specifically disrupting the CUL4B-DDB1 interaction and decreasing the ubiquitination of CRL4B E3 ligase substrates

The direct interaction between Cullin 4B (CUL4B) and DNA damage-binding protein 1 (DDB1) is required for the assembly of Cullin4B-RING E3 ligase complex (CRL4B), which are involved in the tumorigenesis of osteosarcoma through ubiquitinating and degrading multiple tumor suppressors and cell cycle regulators. Thus, targeting CUL4B-DDB1 interaction to prevent the assembly of CRL4B may be a potent approach to inhibit osteosarcoma cell growth. In the present study, we identified six naturally-sourced small molecules that can specifically disrupt the CUL4B-DDB1 interaction using an in vitro high-throughput screening (HTS) system in yeast. We focused our investigation on revealing the molecular effects of TSC01682, the most active compound capable of inhibiting osteosarcoma cell growth. Biochemically, TSC01682 significantly repressed the CUL4B-DDB1 interaction in both yeast cells and osteosarcoma cells. Moreover, TSC01682 treatment in osteosarcoma cells also caused a decrease of other CRL4B components including CUL4-associated factor 11 (DCAF11) and DCAF13, but an increase of two CRL4B substrates including cyclin-dependent kinase inhibitor 1A (CDKN1A, also known as p21) and phosphatase and tensin homolog deleted on chromosome 10 (PTEN) through inhibiting their ubiquitination. Consistent with these molecular changes, TSC01682 treatment significantly inhibited cell proliferation, colony formation, invasion, and in vivo tumor growth. Collectively, our results suggest that TSC01682 is a potent compound capable of disrupting the CUL4B-DDB1 interaction, and it may be developed as a chemotherapeutic drug for osteosarcoma treatment.

The cullin4A is up-regulated in chronic obstructive pulmonary disease patient and contributes to epithelial-mesenchymal transition in small airway epithelium

Background

Chronic obstructive pulmonary disease (COPD) is a common respiratory disease with high morbidity and mortality. The most important pathophysiological change of COPD is airway obstruction. Airway obstruction can cause airflow restriction and obstructive ventilation dysfunction. Currently, many studies have shown that there is EMT phenomenon in the process of airway remodeling of COPD. Cullin4A (CUL4A) is an E3 ubiquitin ligase that interacts with other factors to form the E3 complex. Studies have shown that CLU4A is associated with EMT in non-small cell lung cancer and other cancers. However, its relationship with EMT in COPD has not been reported systematically. In this study, we detected the expression of CUL4A in lung epithelium of COPD patients. In addition, the regulatory effect and mechanism of CUL4A on EMT in COPD were clarified in small airway epithelial cells.

Methods

The expression of CUL4A was assessed by immunohistochemistry in lung epithelium specimens from smokers, non-smokers and patients with chronic obstructive pulmonary disease. The role of CUL4A on cigarette smoke extract (CSE)-induced epithelial-mesenchymal transition (EMT) in human small airway epithelial cells (HSAEpiCs) was assessed by silencing or overexpression CUL4A in vitro. Cigarette smoke is recognized as a high-risk factor in the induction of COPD, and its damage to the airway involves airway damage, airway inflammation and airway remodeling.

Results

The results shown that CUL4A expression in small airway epithelium was significantly increased in patients with COPD. We also observed a significant negative association between CUL4A and FEV₁%, a useful clinical marker for the diagnosis and evaluation of COPD severity, in small airway epithelial cells. In vitro, CSE-induced EMT is associated with high expression of CUL4A, and targeted silencing of CUL4A with shRNA inhibits CSE-induced EMT in human small airway epithelial cells.

Conclusions

Our results showed that CUL4A was overexpressed in lung epithelium of COPD patients, and CUL4A could regulate EMT of human small airway epithelium, which revealed a new mechanism of remodeling of small airway epithelium of COPD patients.

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1048-4) contains supplementary material, which is available to authorized users.

Effects of LDOC1 on colorectal cancer cells via downregulation of the Wnt/β-catenin signaling pathway

Colorectal cancer (CRC) is one of the most common tumor types of the digestive tract. Its incidence and mortality rates are among the highest of all gastrointestinal tumor types. The expression of leucine zipper downregulated in cancer 1 (LDOC1) is decreased in numerous cancer types. In the present study, the aim was to investigate the role of LDOC1 and determine the potential molecular mechanisms of its action in CRC. The expression of LDOC1 in CRC tissues and adjacent normal tissues was detected by reverse transcription-quantitative polymerase chain reaction and immunohistochemistry. LDOC1 expression in four CRC cell lines, compared with normal colorectal tissue, was determined by reverse transcription- polymerase chain reaction (RT-PCR), and two cell lines with relatively low expression were screened. Human LDOC1 cDNA was inserted into a lentiviral vector, and transfected into HCT-116 and Caco2 cell lines. The transfection efficiency was identified by RT-PCR and western blot analysis. Cell proliferation was detected by Cell Counting Kit-8 and colony formation assays. Cell cycle and apoptosis were detected by flow cytometry assay. Migration and invasion were assessed using Transwell and Matrigel assays, respectively. Additionally, whether LDOC1 regulates the Wnt/β-catenin pathway was investigated by western blot analysis, and the expression and localization of β-catenin in CRC cells were demonstrated by cellular immunofluorescence. LDOC1 expression was downregulated in CRC tissues and cells. LDOC1 overexpression inhibited cell proliferation, migration and invasion, but promoted cells apoptosis. Furthermore, LDOC1 downregulated the Wnt/β-catenin pathway in CRC. In conclusion, LDOC1 is a tumor suppressor in CRC and it inhibits cell proliferation and promotes cell apoptosis. Additionally, it inhibits CRC cell metastasis by downregulating the Wnt/β-catenin signaling pathway.