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

DOK7, a target of miR-299-5p, suppresses the progression of bladder cancer

OBJECTIVE

Bladder cancer (BLCA) is the 6th most common malignancy in males. microRNA (miRNAs) can function as tumor suppressors or oncogenic factors, which are of significance in the progression of BLCA. This study explored the mechanisms by which miR-299-5p modulates DOK7 (Docking Protein 7) expression and the functional role of DOK7 in the progression of BLCA.

METHODS

The expression of the DOK7 in BLCA patient samples was examined by RT-qPCR (Real-time quantitative polymerase chain reaction), Western blotting and Immunohistochemical (IHC) staining. The malignant phenotype of BLCA cells upon DOK7 overexpression or silencing was assessed by functional assays including cell count kit-9 (CCK8), colony formation and 5-ethynyl-2'-deoxyuridine (Edu) staining assays, as well as Transwell migration and invasion assays. The miRNA regulators of DOK7 were identified through bioinformatics prediction, and the biological role of miR-299-5p/DOK7 axis was validated by functional assays. The impact of miR-299-5p/DOK7 axis on Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway was further examined by Western blotting.

RESULTS

DOX7 was significantly downregulated in BLCA tumor tissues compared with normal tissues. Ectopic DOK7 expression suppressed the proliferation, migration and invasion of BLCA cells. DOK7 overexpression also attenuated the tumorigenesis of BLCA cells in nude mice. miR-299-5p was a negative regulator of DOK7 expression in BLCA cells. miR-299-5p/DOK7 axis impaired the malignancy of BLCA cells through regulating the JAK signaling pathway.

CONCLUSION

Our data indicate that miR-299-5p/DOK7 axis suppresses BLCA progression possibly by regulating the JAK signaling pathway.

The role of miRNAs in liver diseases: Potential therapeutic and clinical applications

MicroRNAs (miRNAs) are a class of short, non-coding RNAs that function post-transcriptionally to regulate gene expression by binding to particular mRNA targets and causing destruction of the mRNA or translational inhibition of the mRNA. The miRNAs control the range of liver activities, from the healthy to the unhealthy. Considering that miRNA dysregulation is linked to liver damage, fibrosis, and tumorigenesis, miRNAs are a promising therapeutic strategy for the evaluation and treatment of liver illnesses. Recent findings on the regulation and function of miRNAs in liver diseases are discussed, with an emphasis on miRNAs that are highly expressed or enriched in hepatocytes. Alcohol-related liver illness, acute liver toxicity, viral hepatitis, hepatocellular carcinoma, liver fibrosis, liver cirrhosis, and exosomes in chronic liver disease all emphasize the roles and target genes of these miRNAs. We briefly discuss the function of miRNAs in the etiology of liver diseases, namely in the transfer of information between hepatocytes and other cell types via extracellular vesicles. Here we offer some background on the use of miRNAs as biomarkers for the early prognosis, diagnosis, and assessment of liver diseases. The identification of biomarkers and therapeutic targets for liver disorders will be made possible by future research into miRNAs in the liver, which will also help us better understand the pathogeneses of liver diseases.

Siah1 in cancer and nervous system diseases (Review)

The dysregulation of the ubiquitin‑proteasome system will result in the abnormal accumulation and dysfunction of proteins, thus leading to severe diseases. Seven in absentia homolog 1 (Siah1), an E3 ubiquitin ligase, has attracted wide attention due to its varied functions in physiological and pathological conditions, and the numerous newly discovered Siah1 substrates. In cancer and nervous system diseases, the functions of Siah1 as a promoter or a suppressor of diseases are related to the change in cellular microenvironment and subcellular localization. At the same time, complex upstream regulations make Siah1 different from other E3 ubiquitin ligases. Understanding the molecular mechanism of Siah1 will help the study of various signaling pathways and benefit the therapeutic strategy of human diseases (e.g., cancer and nervous system diseases). In the present review, the functions and regulations of Siah1 are described. Moreover, novel substrates of Siah1 discovered in recent studies will be highlighted in cancer and nervous system diseases, providing ideas for future research and clinical targeted therapies using Siah1.

Enhanced expression of miR-889 forecasts an unfavorable prognosis and facilitates cell progression in hepatocellular carcinoma

Background

As a new type of molecular marker, microRNAs (miRNAs) can be used for early diagnosis and prognosis prediction of malignant tumors, and has broad clinical application prospects. This paper mainly studies the important role of miR-889 in the occurrence and development of hepatocellular carcinoma and the prognostic significance of miR-889 in hepatocellular carcinoma.

Methods

Quantitative real-time PCR analysis detected the expression levels of miR-889 in hepatocellular carcinoma tissues and cell lines. Kaplan-Meier curve and Cox regression analysis were used to explore the prognostic significance of miR-889 in hepatocellular carcinoma. The CCK-8 and Transwell assays assay were used to assess cell proliferation, migration, and invasion abilities ability.

Results

The expression of miR-889 in hepatocellular carcinoma tissues was significantly higher than that in adjacent tissues. Overexpression of miR-889 was significantly associated with TNM stage, hepatitis B virus infection, and cirrhosis. Patients with high miR-889 expression had shorter overall survival than those with low miR-889 expression. And functional studies in two hepatocellular carcinoma cell lines have shown that overexpression of miR-889 significantly promoted cell proliferation, migration, and invasion in vitro.

Conclusions

Overall, miR-889 was upregulated in hepatocellular carcinoma tissues and cell lines, and overexpression of miR-889 promoted cell proliferation, migration, and invasion in hepatocellular carcinoma cells. Based on our findings, high expression of miR-889 may promote the progression of hepatocellular carcinoma, and high expression of miR-889 is also forecasted for an unfavorable prognosis in hepatocellular carcinoma.

MiR-320b/RAD21 axis affects hepatocellular carcinoma radiosensitivity to ionizing radiation treatment through DNA damage repair signaling

Hepatocellular carcinoma (HCC) is one of the most common malignancies in the world and is associated with high mortality. Ionizing radiation (IR)-based therapy causes DNA damage, exerting a curative effect; however, DNA damage repair signaling pathways lead to HCC resistance to IR-based therapy. RAD21 is a component of the cohesion complex, crucial for chromosome segregation and DNA damage repair, while it is still unclear whether RAD21 is implicated in DNA damage and influences IR sensitivity in HCC. The current research explores the effect and upstream regulatory mechanism of RAD21 on IR sensitivity in HCC. In the present study, RAD21 mRNA and protein expression were increased within HCC tissue samples, particularly within IR-insensitive HCC tissues. The overexpression of RAD21 partially attenuated the roles of IR in HCC by promoting the viability and suppressing the apoptosis of HCC cells. RAD21 overexpression reduced the culture medium 8-hydroxy-2-deoxyguanosine concentration and decreased the protein levels of γH2AX and ATM, suggesting that RAD21 overexpression attenuated IR treatment-induced DNA damage to HCC cells. miR-320b targeted RAD21 3'-UTR to inhibit RAD21 expression. In HCC tissues, particularly in IR-insensitive HCC tissues, miR-320b expression was significantly downregulated. miR-320b inhibition also attenuated IR treatment-induced DNA damage to HCC cells; more importantly, RAD21 silencing significantly attenuated the effects of miR-320b inhibition on IR treatment-induced DNA damage, suggesting that miR-320b plays a role through targeting RAD21. In conclusion, an miR-320b/RAD21 axis modulating HCC sensitivity to IR treatment through acting on IR-induced DNA damage was demonstrated. The miR-320b/RAD21 axis could be a novel therapeutic target for further study of HCC sensitivity to IR treatment.

Hepigenetics: A Review of Epigenetic Modulators and Potential Therapies in Hepatocellular Carcinoma

Hepatocellular carcinoma is the fifth most common cancer worldwide and the second most lethal, following lung cancer. Currently applied therapeutic practices rely on surgical resection, chemotherapy and radiotherapy, or a combination thereof. These treatment options are associated with extreme adversities, and risk/benefit ratios do not always work in patients' favor. Anomalies of the epigenome lie at the epicenter of aberrant molecular mechanisms by which the disease develops and progresses. Modulation of these anomalous events poses a promising prospect for alternative treatment options, with an abundance of felicitous results reported in recent years. Herein, the most recent epigenetic modulators in hepatocellular carcinoma are recapitulated on.

Host cell factors stimulate HIV-1 transcription by antagonizing substrate-binding function of Siah1 ubiquitin ligase to stabilize transcription elongation factor ELL2

The Siah1 and Siah2 ubiquitin ligases are implicated in diverse biological processes ranging from cellular stress responses, signaling to transcriptional regulation. A key substrate of Siah1 is ELL2, which undergoes proteolysis upon polyubiquitination. ELL2 stimulates transcriptional elongation and is a subunit of the Super Elongation Complex (SEC) essential for HIV-1 transactivation. Previously, multiple transcriptional and post-translational mechanisms are reported to control Siah's expression and activity. Here we show that the activity of Siah1/2 can also be suppressed by host cell factor 1 (HCF1), and the hitherto poorly characterized HCF2, which themselves are not degraded but can bind and block the substrate-binding domain (SBD) of Siah1/2 to prevent their autoubiquitination and trans-ubiquitination of downstream targets including ELL2. This effect stabilizes ELL2 and enhances the ELL2-SEC formation for robust HIV-1 transactivation. Thus, our study not only identifies HCF1/2 as novel activators of HIV-1 transcription through inhibiting Siah1 to stabilize ELL2, but also reveals the SBD of Siah1/2 as a previously unrecognized new target for HCF1/2 to exert this inhibition.

MiR-559 targets GP73 to suppress proliferation and invasion of hepatocellular carcinoma in vitro

Hepatocellular carcinoma (HCC) is one of the common malignant tumors with poor overall prognosis. As a tumor suppressor, the function of miR-559 in HCC is not clear. In this study, quantitative real-time PCR was carried out to measure the expression of miR-559 in HCC cell lines. The effects of miR-559 on HCC cell proliferation, migration, and invasion were evaluated through a series of functional assays. The mechanism through which miR-559 regulates HCC cells was investigated by dual-luciferase reporter assay and functional experiments. The results revealed that miR-559 expression was low in HCC cell lines. Upregulation of miR-559 suppressed HCC cell proliferation, migration, and invasion. Dual-luciferase reporter assay confirmed Golgi membrane protein 73 (GP73) as a target gene of miR-559. Moreover, miR-559 could negatively regulate GP73 expression in HCC cells. These results demonstrated that low-level expression of miR-559 was associated with HCC, and overexpression of miR-559 could inhibit HCC cell growth and invasion via targeting GP73.

Multifaceted Function of MicroRNA-299-3p Fosters an Antitumor Environment Through Modulation of Androgen Receptor and VEGFA Signaling Pathways in Prostate Cancer

Prostate cancer (PCa) is one of the most common cancers to affect men worldwide. Androgen receptor (AR) signaling is central to PCa and PCa therapy. MicroRNAs (miRNAs) play crucial roles in the regulation of prostate cancer through modulation of signaling pathways. In the present study, we illustrate the functional significance and therapeutic benefit of miR-299-3p, an AR targeting microRNA, in PCa progression. We noted loss of expression of miR-299-3p in prostate tumors compared to noncancerous prostate tissues. Replenishment of miR-299-3p in C4-2B, 22Rv-1 and PC-3 cells contributed to cell cycle arrest, reduced proliferation, migration and increased expression of apoptotic markers. Additionally, overexpression of miR-299-3p induced a reduction of AR, PSA and VEGFA expression. AGO-RNA pulldown experiment showed enrichment of AR, VEGFA and miR-299-3p in C4-2B cells overexpressing miR-299-3p. miR-299-3p overexpression also inhibited epithelial mesenchymal transition, expression of Slug, TGF-β3, phospho-AKT and phospho-PRAS40, but increased expression of E-cadherin. Furthermore, miR-299 overexpression resulted in reduced tumor growth in xenograft models and increased drug sensitivity. Overall, this study has identified novel mechanisms of antitumor and antimigration function of miR-299-3p through modulation of AR and VEGFA signaling pathways which lead to improved drug sensitivity of PCa.

Ubiquitin, SUMO, and Nedd8 as Therapeutic Targets in Cancer

Ubiquitin defines a family of approximately 20 peptidic posttranslational modifiers collectively called the Ubiquitin-like (UbLs). They are conjugated to thousands of proteins, modifying their function and fate in many ways. Dysregulation of these modifications has been implicated in a variety of pathologies, in particular cancer. Ubiquitin, SUMO (-1 to -3), and Nedd8 are the best-characterized UbLs. They have been involved in the regulation of the activity and/or the stability of diverse components of various oncogenic or tumor suppressor pathways. Moreover, the dysregulation of enzymes responsible for their conjugation/deconjugation has also been associated with tumorigenesis and cancer resistance to therapies. The UbL system therefore constitutes an attractive target for developing novel anticancer therapeutic strategies. Here, we review the roles and dysregulations of Ubiquitin, SUMO, and Nedd8 pathways in tumorigenesis, as well as recent advances in the identification of small molecules targeting their conjugating machineries for potential application in the fight against cancer.