miR-634 exhibits anti-tumor activities toward hepatocellular carcinoma via Rab1A and DHX33

circ_WASF2 regulates ferroptosis by miR-634/ GPX4 signaling in pancreatic cancer

PURPOSE

Pancreatic cancer (PC) is one of the most lethal malignant gastrointestinal tumors (GI) characterized by a poor prognosis. Ferroptosis is an emerging programmed cell death that plays an essential role in the progression of various cancers. Ferroptosis is driven by iron-dependent phospholipid peroxidation and is regulated by mitochondrial activity, lipid peroxidation, and reactive oxygen species (ROS). The function and mechanism of ferroptosis in PC need more research.

METHODS

The levels of circRNAs, miRNAs, and mRNAs were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Western blot was used for protein detection. CCK8 assays were used to detect cell proliferation. Cell death, lipid peroxidation, ROS, and Fe2+ were detected by indicted kits. Dual-luciferase reporter and RNA pull-down assays were conducted to confirm the interaction between circRNAs, miRNAs, and mRNAs.

RESULTS

In this research, we found that circular RNA hsa_circ_0000003(circ_WASF2) was upregulated in pancreatic cancer cells. The silence of circ_WASF2 inhibited cancer proliferation and increased cell death by increasing ferroptosis accompanied by up-regulation of lipid peroxidation, ROS, and Fe2+. Further studies showed that circ_WASF2 could attenuate ferroptosis by targeting miR-634 and the downstream glutathione peroxidase 4 (GPX4). GPX4 has been well-reported as a central factor in ferroptosis. Our research revealed a new pathway for regulating ferroptosis in PC.

CONCLUSION

In summary, we have determined that circ_WASF2/miR-634/GPX4 contributed to ferroptosis-induced cell death, and provided a possible therapeutic target in PC.

Development of small molecule inhibitors targeting RNA helicase DHX33 as anti-cancer agents

RNA helicase DHX33 has been identified to be a critical factor in promoting cancer development. Genetic deletion of DHX33 significantly blocks tumorigenesis. Importantly, its helicase activity was found to be pivotal for exerting cellular functions. Herein we used a helicase-based high throughput screening (HTS) to discover DHX33 inhibitors from Chembridge chemical library containing 15,000 small molecules. We identified a hit compound containing benzimidazole ring that demonstrated activity against DHX33 with certain selectivity. Further structural optimization led to the design and synthesis of a series of analog inhibitors. Considering the potential role of DHX33 in cancer development, the compounds were evaluated based on the cytotoxicity activity in U251-MG cancer cells in vitro. Among them, compound IVa (KY386) was identified to be a selective inhibitor for DHX33 helicase with potent anti-cancer activity and moderate metabolic stability. These results support the promising role of DHX33 inhibitors for development of novel anti-cancer drugs.

Hsa_circ_0081069 facilitates tongue squamous cell carcinoma progression by modulating MAP2K4 expression via miR-634

It has been demonstrated that circular RNA (circRNA) is involved in the progression of tongue squamous cell carcinoma (TSCC). The aim of this study was to investigate the intrinsic mechanism of circ_0081069 in TSCC progression. The expression levels of circ_00081069, miR-634, and mitogen-activated protein kinase kinase 4 (MAP2K4) in TSCC tissues and cells were detected by quantitative real-time PCR (qRT-PCR). Cell counting kit 8 assay, Edu assay, and flow cytometry assay were used to detect cell proliferation and cell cycle distribution. Transwell assay was used to detect cell migration and invasion abilities. Western blot analysis was performed to detect the protein expression. Dual-luciferase reporter assay was used to detect the targeting relationships of circ_0081069, miR-634 and MAP2K4. Immunohistochemical staining was used to measure MAP2K4-positive cells in tissues. The effect of circ_0081069 silencing on tumor formation in TSCC in vivo was explored by xenograft tumor assay. Circ_0081069 was highly expressed in TSCC tissues and cells. Silencing of circ_0081069 inhibited cell proliferation, cell cycle progress, cell migration and invasion in vitro, as well as hindered tumor growth in vivo. Mechanistically, circ_0081069 targeted miR-634 to negatively regulate miR-634 expression, and inhibition of miR-634 was able to weaken the inhibitory effect of circ_0081069 knockdown on proliferation, migration, and invasion of TSCC cells. MiR-634 targeted MAP2K4 and negatively regulated MAP2K4 expression, and overexpression of miR-634 inhibited TSCC cell proliferation, migration, and invasion, while co-overexpression of MAP2K4 was able to reverse the effects of miR-634 in TSCC cells. Circ_0081069 is involved in the regulation of proliferation, cycle progress, migration, and invasion of TSCC cells through the miR-634/MAP2K4 axis and has the potential to serve as a diagnostic biomarker and therapeutic target.

Circular RNA lysophosphatidic acid receptor 3 (circ-LPAR3) enhances the cisplatin resistance of ovarian cancer

Circular RNA (circRNA) is considered to be an important regulator that mediates cancer chemoresistance. But whether circ-LPAR3 is involved in ovarian cancer (OC) cisplatin (DDP) resistance is unclear. The circ-LPAR3, miR-634 and pyruvate dehydrogenase kinase 1 (PDK1) expression was measured by quantitative real-time PCR (qRT-PCR). Cell cisplatin resistance and viability were measured by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide (MTT) assay. In addition, cell colony number, apoptosis, and metastasis were assessed by colony formation assay, flow cytometry and transwell assay. Furthermore, in vivo experiments were performed by constructing mice xenograft models. RNA interaction was confirmed by dual-luciferase reporter assay, and PDK1 protein expression was examined by Western blot analysis. Our results showed that circ-LPAR3 was markedly upregulated in DDP-resistant OC tissues and cells. Silencing of circ-LPAR3 enhanced the DDP sensitivity of OC cells and tumors. MiR-634 could interact with circ-LPAR3, and its inhibitor overturned the regulation of si-circ-LPAR3 on cell DDP resistance. Additionally, PDK1 was targeted by miR-634, and its overexpression inverted the effect of miR-634 on cell DDP resistance. To sum up, circ-LPAR3 might contribute to the DDP resistance of OC via the miR-634/PDK1 axis.

Long noncoding RNA NEAT1 changes exosome secretion and microRNA expression carried by exosomes in hepatocellular carcinoma cells

BACKGROUND

This study aimed to investigate the roles and functions of nuclear-enriched abundant transcript 1 (NEAT1) in exosome secretion and exosomal microRNA (miRNA) changes in hepatocellular carcinoma (HCC) cells.

METHODS

HepG2 and HuH-7 cells were divided into two groups: Lv-control (which were infected with lentivirus without NEAT1 expression) and Lv-NEAT1 (which were infected with lentivirus with NEAT1 overexpression). Each group was used to study cell function (proliferation, invasion, and apoptosis) and exosome secretion by nanoparticle tracking analysis (NTA), electron microscopy, and nanoflow cytometry (nanoFCM). Different levels of messenger RNA (mRNA), miRNA, and exosomal miRNA were detected by RNA sequencing. Next, potential target RNAs were verified by reverse transcription polymerase chain reaction (RT-PCR). Changed exosomal miRNAs were found and miRNA mimics were used to study cell function in NEAT1-overexpression and NEAT1-knockdown HCC cells.

RESULTS

The data showed that NEAT1-overexpression promoted exosome secretion. The overexpression of NEAT1 altered global genes, including exosome-related genes. Compared with the control group, we observed that several miRNAs changed in the exosomes secreted by NEAT1-overexpressing cells. Our study found that these changed exosomal miRNAs played a suppressor role in HCC. Transfection of miR-634, miR-638, and miR-3960 reversed the enhanced invasion and proliferation in HCC cells with a high level of NEAT1 expression.

CONCLUSIONS

These results suggested that NEAT1 regulates exosome-related genes, which might be associated with increasing exosome secretion by NEAT1-overexpressing cells. Furthermore, NEAT1 promotes cell invasion and proliferation via downregulation of miR-634, miR-638, and miR-3960 in exosomes. This study may provide potential targets for exosome-mediated miRNA transfer in HCCs with a high level of NEAT1 expression therapy.

Long non-coding RNA HOTAIR promotes hepatocellular carcinoma progression by regulating miR-526b-3p/DHX33 axis

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common human cancers. Long non-coding RNAs (lncRNAs) play pivotal roles in progression of various cancers, including HCC.

OBJECTIVE

We aimed to explore the exact role and underlying mechanism of lncRNA HOX transcript antisense intergenic RNA (HOTAIR) in HCC.

METHODS

Quantitative real time polymerase chain reaction (qRT-PCR) was carried out to determine the levels of HOTAIR, DEAH-box helicase 33 (DHX33) and miR-526b-3p. Western blot assay was used to detect the protein level of DHX33. Besides, cell proliferation and apoptosis were assessed by methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay and flow cytometry analysis, respectively. Cell migration and invasion were detected by transwell assay. The interaction between miR-526b-3p and HOTAIR or DHX33 was predicted by starbase and confirmed by the dual-luciferase reporter assay. Murine xenograft model was established through injecting Huh7 cells transfected with sh-NC or sh-HOTAIR.

RESULTS

The levels of HOTAIR and DHX33 were increased in HCC tissues and cells. Knockdown of either HOTAIR or DHX33 suppressed proliferation, migration and invasion but increased apoptosis in HCC cells. Moreover, DHX33 overexpression reversed the suppressive effect of HOTAIR knockdown on progression of HCC cells. Interestingly, miR-526b-3p could directly bind to HOTAIR, and DHX33 was a direct target of miR-526b-3p. Additionally, interference of HOTAIR restrained the tumor growth by upregulating miR-526b-3p and downregulating DHX33 in vivo.

CONCLUSIONS

HOTAIR knockdown suppressed cell proliferation, migration and invasion, and promoted apoptosis via regulating miR-526b-3p/DHX33 axis in HCC cells, providing a potential avenue for treatment of HCC.

Ubiquitin-specific protease 2a promotes hepatocellular carcinoma progression via deubiquitination and stabilization of RAB1A

PURPOSE

Deubiquitination, the inverse process of ubiquitination, is catalyzed by deubiquitinases (DUBs) that remove ubiquitin from target proteins and subsequently prevent their degradation by proteasomes. Previously, deubiquitination has been found to be involved in hepatocellular carcinoma (HCC) progression. As yet, however, little is known about the exact role of deubiquitination in the development and/or progression of this type of cancer.

METHODS

HCC tissues and tissue microarrays were used to detect expression of the DUB ubiquitin-specific protease 2a (USP2a). The critical role of USP2a in HCC development and progression was assessed in both in vitro cell and in vivo animal models. LC-MS/MS analyses were performed to identify potential targets of USP2a in HCC cells, after which regulation of target protein stability and ubiquitin status by USP2a were investigated.

RESULTS

We found that USP2a was significantly upregulated in HCC tissues, and that a high expression was positively associated with a poor prognosis. Subsequently, we found that USP2a silencing resulted in inhibition of HCC cell proliferation, migration and invasion, whereas exogenous USP2a overexpression resulted in the opposite effects, both in vitro and in vivo. Mechanistically, LC-MS/MS analysis revealed that RAB1A, a key regulator of the ER and Golgi vesicular transport system, serves as a potential target of USP2a in HCC cells. In addition, we found that USP2a can deubiquitinate and stabilize RAB1A and prevent its degradation, and that this process is required for inducing HCC progression by USP2a.

CONCLUSIONS

Our data indicate that USP2a can promote HCC progression via deubiquitination and stabilization of RAB1A. This observation indicates that DUB targeting may serve as a novel approach to improve the treatment of HCC.

Seed-mediated RNA interference of androgen signaling and survival networks induces cell death in prostate cancer cells

Resistance to anti-androgen therapy in prostate cancer (PCa) is often driven by genetic and epigenetic aberrations in the androgen receptor (AR) and coregulators that maintain androgen signaling activity. We show that specific small RNAs downregulate expression of multiple essential and androgen receptor-coregulatory genes, leading to potent androgen signaling inhibition and PCa cell death. Expression of different short hairpin/small interfering RNAs (sh-/siRNAs) designed to target TMEFF2 preferentially reduce viability of PCa but not benign cells, and growth of murine xenografts. Surprisingly, this effect is independent of TMEFF2 expression. Transcriptomic and sh/siRNA seed sequence studies indicate that expression of these toxic shRNAs lead to downregulation of androgen receptor-coregulatory and essential genes through mRNA 3′ UTR sequence complementarity to the seed sequence of the toxic shRNAs. These findings reveal a form of the “death induced by survival gene elimination” mechanism in PCa cells that mainly targets AR signaling, and that we have termed androgen network death induced by survival gene elimination (AN-DISE). Our data suggest that AN-DISE may be a novel therapeutic strategy for PCa.

Novel insights into the interaction between long non-coding RNAs and microRNAs in glioma

Glioma is the most common brain tumor of the central nervous system. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been identified to play a vital role in the initiation and progression of glioma, including tumor cell proliferation, survival, apoptosis, invasion, and therapy resistance. New documents emerged, which indicated that the interaction between long non-coding RNAs and miRNAs contributes to the tumorigenesis and pathogenesis of glioma. LncRNAs can act as competing for endogenous RNA (ceRNA), and molecular sponge/deregulator in regulating miRNAs. These interactions stimulate different molecular signaling pathways in glioma, including the lncRNAs/miRNAs/Wnt/β-catenin molecular signaling pathway, the lncRNAs/miRNAs/PI3K/AKT/mTOR molecular signaling pathway, the lncRNAs-miRNAs/MAPK kinase molecular signaling pathway, and the lncRNAs/miRNAs/NF-κB molecular signaling pathway. In this paper, the basic roles and molecular interactions of the lncRNAs and miRNAs pathway glioma were summarized to better understand the pathogenesis and tumorigenesis of glioma.

Growing Evidence of Exosomal MicroRNA-Related Metastasis of Hepatocellular Carcinoma

Metastasis is the prominent cause of death in patients with hepatocellular carcinoma (HCC); however, the mechanisms behind HCC metastasis are not well understood. MicroRNAs (miRs) can regulate gene expression and affect HCC metastasis. Exosomes can transport miRs and other cargoes to and from different cells, thus being associated with tumour-distant metastasis. Exosomal miRs involve different processes of HCC metastasis through their functional effects, such as their induction of epithelial-to-mesenchymal transition, angiogenesis, and distant niche. In this review, data from the literature were analysed and summarised, with a focus on the evidence extraction of exosomal miRs in HCC metastasis with the purpose of increasing the understanding of the mechanisms behind HCC metastasis and acquiring implications for application.

CircRNA circUGGT2 Contributes to Hepatocellular Carcinoma Development via Regulation of the miR-526b-5p/RAB1A Axis

Background

Hepatocellular carcinoma (HCC) is a common malignant tumor in the world. Circular RNA hsa_circ_0008274 (circUGGT2) is reported to be upregulated in HCC tissues. Notwithstanding, the role and regulatory mechanism of circUGGT2 in HCC are indistinct.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was implemented to examine the levels of circUGGT2, microRNA (miR)-526b-5p, and ras-related protein Rab-1A (RAB1A) mRNA in HCC tissues and cells. Cell proliferation and colony formation were assessed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) or colony formation assays. The levels of cyclin D1, proliferating cell nuclear antigen (PCNA), and RAB1A were detected with Western blotting. Cell cycle progression, migration, and invasion were evaluated by using flow cytometry or transwell assays. The relationship between circUGGT2 or RAB1A and miR-526b-5p was verified via dual-luciferase reporter and/or RNA pull-down assays. Xenograft assay was executed to confirm the role of circUGGT2 in vivo.

Results

We observed that circUGGT2 and RAB1A were upregulated while miR-526b-5p was downregulated in HCC tissues and cells. CircUGGT2 silencing suppressed tumor growth in vivo and curbed proliferation, colony formation, cell cycle progression, migration, and invasion of HCC cells in vitro. Mechanically, circUGGT2 regulated RAB1A expression via competitively binding to miR-526b-5p. Also, the inhibitory influence of circUGGT2 silencing on the malignancy of HCC cells was overturned by miR-526b-5p inhibitor. Furthermore, RAB1A overexpression reversed the suppressive influence of miR-526b-5p mimic on the malignancy of HCC cells.

Conclusion

CircUGGT2 silencing inhibited HCC development via modulating the miR-526b-5p/RAB1A axis, providing a possible target for HCC treatment.

Hsa_circ_0084927 Regulates Cervical Cancer Advancement via Regulation of the miR-634/TPD52 Axis

Background

Cervical cancer (CC) is a common gynecological tumor that affects women’s health. Circular RNA hsa_circ_0084927 (hsa_circ_0084927) has been reported to be upregulated in CC. However, the role and regulatory mechanism of hsa_circ_0084927 in CC are unclear.

Methods

Expression of hsa_circ_0084927, microRNA (miR)-634, and tumor protein D52 (TPD52) mRNA in CC tissues and cells was examined by quantitative real-time polymerase chain reaction (qRT-PCR). The proliferation, colony formation, cell cycle progression, apoptosis, migration, and invasion of CC cells were determined with cell counting kit-8 (CCK-8), plate clone, flow cytometry, or transwell assays. The levels of cyclin D1, cleaved-caspase-3 (c-caspase 3), matrix metalloproteinase (MMP)-2, MMP-9, and TPD52 protein were evaluated with Western blotting. The targeting relationship between hsa_circ_0084927 or TPD52 and miR-634 was verified via dual-luciferase reporter and/or RNA immunoprecipitation (RIP) assays. Xenograft assay was conducted to confirm the role of hsa_circ_0084927 in vivo.

Results

Hsa_circ_0084927 and TPD52 were upregulated while miR-634 was downregulated in CC tissues and cells. Hsa_circ_0084927 silencing reduced tumor growth in vivo and induced cell cycle arrest, apoptosis, and curbed proliferation, colony formation, migration, and invasion of CC cells in vitro. Hsa_circ_0084927 regulated TPD52 expression through sponging miR-634. MiR-634 inhibitor reversed hsa_circ_0084927 knockdown-mediated impact on the malignancy of CC cells. TPD52 elevation abolished the repressive influence of miR-634 mimics on the malignancy of CC cells.

Conclusion

Hsa_circ_0084927 accelerated CC advancement via upregulating TPD52 via sponging miR-634, offering a new evidence to support hsa_circ_0084927 as a promising target for CC treatment.

[Effects of RAB1A on the proliferation, invasion, and metastasis of tongue squamous cell carcinoma cells]

OBJECTIVE

This study aimed to investigate the molecular mechanism of RAB1A in the proliferation, invasion, and metastasis of human tongue squamous cell carcinoma.

METHODS

Western blot was used to detect the expression of RAB1A protein in human normal tongue epithelial cells (Hacat) and tongue squamous cell carcinoma Tca8113. The changes in RAB1A after plasmid transfection were also studied. The Tca8113 cells were named SiRAB1A/Tca8113 after RAB1A plasmid transfection. The expression of the epithelial-mesenchymal transition (EMT)-related markers of SiRAB1A/Tca8113 cells was also detected. CCK-8 assay was used to detect the proliferation of SiRAB1A/Tca8113 cells. Transwell and wound healing assays were used to detect the invasive and metastatic abilities of SiRAB1A/Tca8113 cells, respectively.

RESULTS

Western blot results showed that the expression of RAB1A in tongue squamous cell carcinoma cells was significantly higher than that in Hacat. RAB1A decreased significantly after SiRAB1A plasmid transfection. CCK-8 proliferation assay showed that the proliferation of SiRAB1A/Tca8113 cells also decreased significantly. Transwell and wound healing assays demonstrated that the invasive and metastatic abilities of SiRAB1A/Tca8113 cells decreased significantly, respectively. In addition, Western blot results demonstrated that RAB1A deletion significantly increased the expression of E-cadherin and inhibited the expression of Vimentin.

CONCLUSIONS

RAB1A could promote the proliferation, invasion, and metastasis of tongue squamous cell carcinoma cells.

Circular RNA_0001742 has potential to predict advanced tumor stage and poor survival profiles in tongue squamous cell carcinoma management

Background

Circular RNA_0001742 (circ_0001742) has been reported to be upregulated in tongue squamous cell carcinoma (TSCC) tissues/cells and regulate TSCC cell proliferation, migration, and invasion. This study aimed to further investigate the clinical significance of circ_0001742 in TSCC management.

Methods

Totally, 146 TSCC patients underwent surgical treatment were reviewed. Their fresh‐frozen tumor tissue and adjacent tissue were acquired for detecting circ_0001742 expression via reverse transcription‐quantitative polymerase chain reaction. According to circ_0001742 expression in tumor tissue, all patients were classified as tumor circ_0001742 low (0%‐50% percentile) and high (50%‐100% percentile) patients, the latter were further divided into the tumor circ_0001742 high+ (50%‐75% percentile), high++ (75%‐90% percentile), and high+++ (90%‐100% percentile) patients, respectively.

Results

Circ_0001742 expression was increased in TSCC tumor tissue compared with adjacent tissue, and it presented good value in discriminating tumor tissue from adjacent tissue (area under the curve (AUC): 0.870, 95% CI: 0.831‐0.910). Tumor high circ_0001742 expression was associated with higher T stage, N stage, and TNM stage, but not age, gender, or pathological grade. Furthermore, OS was reduced in tumor circ_0001742 high patients compared with tumor circ_0001742 low patients; moreover, OS was the shortest in tumor circ_0001742 high+++ patients, followed by tumor circ_0001742 high++ patients and tumor circ_0001742 high+ patients, and the longest in tumor circ_0001742 low patients. In addition, multivariate Cox's regression analysis revealed that higher tumor circ_0001742 expression was an independent predictive factor for decreased OS.

Conclusion

Circ_0001742 serves as a potential biomarker for advanced tumor stage and poor survival in TSCC patients.

Circ_0000218 plays a carcinogenic role in colorectal cancer progression by regulating miR-139-3p/RAB1A axis

Accumulating researches have confirmed that circRNA abnormal expression plays a prominent role in the progression of colorectal cancer (CRC). The role of circ_0000218 in CRC and its potential mechanism are not clear. In this study, real-time polymerase chain reaction (RT-PCR) was employed to measure the circ_0000218, miR-139-3p and RAB1A mRNA expression in CRC tissues and cells. Immunohistochemistry and western blot were conducted to determine the RAB1A expression in CRC tissues and cells, respectively. Colony formation assay and BrdU method were employed to monitor the effect of circ_0000218 on cell proliferation. Transwell assay was adopted to detect cell migration and invasion. Dual luciferase reporter assay and RNA immunoprecipitation assay were adopted to confirm the targeting relationship between circ_0000218 and miR-139-3p, miR-139-3p and RAB1A. We demonstrated that circ_0000218 was notably upregulated in CRC tissues and cell lines, and its high expression level was markedly linked to the increase of T staging and local lymph node metastasis. Circ_0000218 overexpression enhanced the proliferation and metastasis of CRC cells while knocking down circ_0000218 caused the opposite effects. We also observed that miR-139-3p was negatively regulated by circ_0000218, while RAB1A was positively regulated by it. Collectively, this study suggested that circ_0000218 upregulated RAB1A and promoted CRC proliferation and metastasis via sponging miR-139-3p.

miR-634 Decreases the Radioresistance of Human Breast Cancer Cells by Targeting STAT3

Background: Breast cancer is the second most common cancer in women, which is usually treated by radiation therapy. However, resistance of cancer cells to radiation therapy has made treatment difficult. Therefore, finding effective ways to reduce the radiation resistance of cancer cells is an urgent problem to be solved. Materials and Methods: MCF-7 and MDA-MB-231 cells (on accepting radiation) were established to model radiation resistance, namely MCF-7/R and MDA-MB-231/R. The authors then examined the expression of miR-634 through quantitative reverse transcription-polymerase chain reaction. MCF-7/R and MDA-MB-231/R cells were transfected with overexpressed miR-634 mimics. In addition, TargetScan predicted which binding site was targeted by miR-634, and luciferase assay detected the signal transducer and activator of transcription 3 (STAT3) 3'UTR luciferase activity after transfection of mimics expressing miR-634 into HEK-293 cells. 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), flow cytometry, and western blot assays were used for examination of different levels of biological function. Results: miRNA-634 expression was significantly decreased in radiated MCF-7 and MDA-MB-231 cells. When miR-634 mimic was transfected into radiation-resistant MCF-7/R and MDA-MB-231/R cells, the survival rate of radiation-tolerant cells was significantly reduced. Moreover, STAT3 was found to directly interact with miR-634, and further studies demonstrated that miR-634 negatively regulated STAT3. Conclusion: miR-634 was able to regulate STAT3 and enhance the sensitivity of breast cancer cells to radiation; these results might shed new light on radiation therapy for breast cancer.

MicroRNA-634 functions as a tumor suppressor in pancreatic cancer via directly targeting heat shock-related 70-kDa protein 2

Pancreatic cancer (PC) is one of the most malignant types of human cancer and has an extremely poor prognosis. MicroRNAs (miRs) reportedly serve a critical role in pancreatic ductal adenocarcinoma (PDAC) progression. Understanding the expression patterns and functions of miRs may provide strategies for the diagnosis and treatment of patients with PC. In particular, miR-634 is attracting interest due to its critical role in regulating the biology of some types of cancer. However, the expression patterns, biological function and molecular mechanism of miR-634 in PC remain unknown. In the present study, miR-634 expression levels in PC tissues and cell lines were significantly downregulated. Notably, the ectopic overexpression of miR-634 in PC cells inhibited tumor progression, whereas miR-634 silencing reversed these effects. Furthermore, reverse transcription-quantitative polymerase chain reaction, western blot analysis and the dual-luciferase assay revealed that miR-634 regulated heat shock-related 70 kDa protein 2 (HSPA2) by directly binding to its 3-untranslated region. In clinical samples of PC, miR-634 was inversely correlated with HSPA2, which was upregulated in PC. In the rescue experiment, HSPA2 overexpression partially abrogated the effects of miR-634 mimicry on biological function. In conclusion, miR-634 functioned as a tumor suppressor in regulating PC progression by targeting HSPA2 and may therefore be a novel potential therapeutic target for PC.

The Role of MicroRNAs in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers, leading to the second cancer-related death in the global. Although the treatment of HCC has greatly improved over the past few decades, the survival rate of patients is still quite low. Thus, it is urgent to explore new therapies, especially seek for more accurate biomarkers for early diagnosis, treatment and prognosis in HCC. MicroRNAs (miRNAs), small noncoding RNAs, are pivotal participants and regulators in the development and progression of HCC. Great progress has been made in the studies of miRNAs in HCC. The key regulatory mechanisms of miRNAs include proliferation, apoptosis, invasion, metastasis, epithelial-mesenchymal transition (EMT), angiogenesis, drug resistance and autophagy in HCC. And exosomal miRNAs also play important roles in proliferation, invasion, metastasis, and drug resistance in HCC by regulating gene expression in the target cells. In addition, some miRNAs, including exosomal miRNAs, can be as potential diagnostic and prediction markers in HCC. This review summarizes the latest researches development of miRNAs in HCC in recent years.

Alternative translation initiation from two in-frame start codons in DHX33 gene

DHX33 has been shown to play key roles in promoting cell proliferation. We have previously found that DHX33 protein is a doublet. In this report, we discovered that DHX33 doublet is due to alternative translation initiation by two in-frame initiation codons. This is supported by studies from both cell lines and mouse models. DHX33 translation initiation from either AUG codon happens at equal efficiency. Short DHX33 protein has similar cellular location and functions with full-length DHX33. Our results suggest that leaky scanning normally occur in DHX33 mRNA translation, which may serve as a safeguard mechanism to ensure optimal DHX33 translation efficiency. This is the first report of DEAD/DEAH box proteins that can be regulated by alternative translation initiation.

Recombinant DHX33 Protein Possesses Dual DNA/RNA Helicase Activity

RNA helicase DHX33 has been shown to participate in a variety of cellular activities, including ribosome biogenesis, protein translation, and gene transcription. We and others further discovered that DHX33 is strongly expressed in several types of human cancers and plays important roles in promoting cancer cell proliferation. To better understand the molecular mechanism for DHX33 in exerting its biological functions, we purified recombinant DHX33 and performed biochemical studies in vitro. DHX33 protein was found to have ATPase activity that is dependent on DNA or RNA duplexes. The ATPase activity of DHX33 is coupled with its RNA/DNA unwinding activity. If a key residue in the ATP binding site were mutated, the mutant DHX33 could not unwind DNA/RNA duplexes. Furthermore, a deletion mutant of a RKK motif previously identified to be involved in ribosome DNA binding could still unwind DNA duplexes, albeit with reduced efficiency. In summary, our study reveals that purified DHX33 protein possesses unwinding activity toward DNA and RNA duplexes.

A novel RNA sequencing-based miRNA signature predicts with recurrence and outcome of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common type of cancer and the second leading cause of cancer-related deaths worldwide. Given that the rate of HCC recurrence 5 years after liver resection is as high as 70%, patient with HCC typically has a poor outcome. A biomarker or set of biomarkers that could predict disease recurrence would have a substantial clinical impact, allowing earlier detection of recurrence and more effective treatment. With the aim of identifying a new microRNA (miRNA) signature associated with HCC recurrence, we analyzed data on 306 patients with HCC for whom both miRNA expression profiles and complete clinical information were available from The Cancer Genome Atlas database. Through this analysis, we identified a six-miRNA signature that could effectively predict patients' recurrence risk; the high-risk and low-risk groups had significantly different recurrence-free survival rates. Time-dependent receiver operating characteristic analysis indicated that this signature had a good predictive performance. Multivariable Cox regression and stratified analyses demonstrated that the six-miRNA signature was independent of other clinical features. Functional enrichment analysis of the gene targets of the six prognostic miRNA indicated enrichment mainly in cancer-related pathways and important cell biological processes. Our results support use of this six-miRNA signature as an independent factor for predicting recurrence and outcome of patients with HCC.

Hypoxia-mediated miR-212-3p downregulation enhances progression of intrahepatic cholangiocarcinoma through upregulation of Rab1a

Rab1a, a member RAS oncogene family, has been reported playing important role in tumor proliferation and migration. However, the role of Rab1a in intrahepatic cholangiocarcinoma (ICC) is not clear. In this study, we found Rab1a was overexpressed in ICC tissues both in mRNA and protein level. Kaplan-meier analysis showed that high expression of Rab1a was associated with poor prognosis of ICC patients. Suppression of Rab1a led to lower proliferation rate and migration ability both in vitro and in vivo by inhibiting process of cell cycle and Epithelial-Mesenchymal Transition (EMT). Further study showed that Rab1a was targeting regulated by miR-212-3p.In addition, expression of Rab1a was increased while miR-212-3p was decreased under hypoxia condition. In conclusion, these findings extend our understanding of Rab1a in progression of ICC, and we found hypoxia/miR-212-3p/Rab1a pathway played important role for progression of ICC. This newly identified pathway should promote the development of novel therapeutic biomarker for ICC.

PDZ binding kinase, regulated by FoxM1, enhances malignant phenotype via activation of β-Catenin signaling in hepatocellular carcinoma

Deregulation of serine/threonine kinase contributes to the development and progression of human diseases. PDZ-binding kinase (PBK) has been implicated in the malignant process of cancers, but its role and clinical significance in hepatocellular carcinoma (HCC) remains unclear. Here we show that PBK expression is increased and associated with larger tumor size, presence of vascular invasion, lymph node metastasis and poor overall and disease-free survivals in two independent cohorts of 879 patients with HCC. In vitro and in vivo data demonstrate PBK exerts oncogenic functions in HCC via activation of β-Catenin signaling pathway. The inhibition of β-Catenin by siRNAs or XAV-939 significantly attenuates PBK-mediated malignant phenotypes. PBK is further identified as a downstream effector of FoxM1. In clinical samples, PBK expression is positively correlated with the expression of FoxM1 and nuclear β-Catenin. Collectively, these findings suggest PBK functions as an oncogene in HCC and the newly identified FoxM1/PBK/β-Catenin axis serves as a promising prognostic factor as well as therapeutic intervention for HCC.

MiR-634 sensitizes glioma cells to temozolomide by targeting CYR61 through Raf-ERK signaling pathway

Glioma is the most common intracranial malignant tumors, accounting for about 40% of intracranial tumors. Primary or secondary drug resistance is one of the main reasons for the failure of treatment. The oncogenic or tumor-suppressive roles of miR-634 have been revealed in different types of cancer. However, the role of miR-634 in glioma remains unknown and whether miR-634 could sensitize glioma cells to temozolomide also is unclear. Here, we aim to investigate the biological function of miR-634 and the possible mechanisms in glioma. In this study, we found that miR-634 was downregulated in glioma tissues compared with normal brain tissues, and its expression was associated with tumor size and WHO grade. Importantly, glioma patients with low miR-634 expression showed a shorter survival time than patients which had high expression of miR-634. This study also showed that miR-634 was decreased in temozolomide-resistant glioma cells, and restoration of miR-634 could sensitize the resistant cells to temozolomide by targeting CYR61 through Raf-ERK signaling. Our study provides a potential target for overcome drug resistance in glioma.

Expression of miR-634 in gastric carcinoma and its effects on proliferation, migration, and invasion of gastric cancer cells

This study aims to observe the expression of microRNA (miR)‐634 in different gastric cancer cell lines and tissues, and to study the effects of miR‐634 on the proliferation, migration, and invasion of the gastric cancer cells. The miR‐634 mimics and miR‐634 inhibitors were transfected by lentivirus into human gastric cancer SGC‐7901 and MGC‐803 cells, and the miR‐634 cells without transfection were used as the control group (NC group). The expression of miR‐634 in the transfected cells was detected by qRT‐PCR. Cell viability was measured by the CCK8 assay. The migration and invasion ability of the cells were detected by scratch assays and Transwell^® chamber assays, respectively, and the luciferase assay verified the binding of miR‐634 to the target gene JAG1. The expression level of miR‐634 in gastric cancer tissues and cell lines was significantly lower than that in normal adjacent tissues and control cells. The survival of cells was significantly decreased, and number of cells migrating and invading was decreased in the miR‐634 mimics group. However, in the miR‐634 inhibitor group, the opposite results were observed. Over‐expression of miR‐634 inhibited the proliferation, migration, and invasion of gastric cancer cell lines, and the miR‐634 target gene was JAG1.

LncRNA DANCR functions as a competing endogenous RNA to regulate RAB1A expression by sponging miR-634 in glioma

Long noncoding RNA (lncRNA) differentiation antagonizing nonprotein coding RNA (DANCR) plays important regulatory roles in many solid tumors. However, the effect of DANCR in glioma progression and underlying molecular mechanisms were not entirely explored. In the present study, we determined the expression of DANCR in glioma tissues and cell lines using qRT-PCR and further defined the biological functions. Furthermore, we used luciferase reporter assay, Western blot, and RNA immunoprecipitation (RIP) to explore the underlying mechanism. Our results showed that DANCR was significantly up-regulated in glioma tissues and cell lines (U251, U118, LN229, and U87MG). High DANCR expression was correlated with advanced tumor grade. Inhibition of DANCR suppressed the glioma cells proliferation and induced cells arrested in the G0/G1 phase. In addition, we verified that DANCR could directly interact with miR-634 in glioma cells and this interaction resulted in the inhibition of downstream of RAB1A expression. The present study demonstrated that DANCR/miR-634/RAB1A axis plays crucial roles in the progression of glioma, and DANCR might potentially serve as a therapeutic target for the treatment of glioma patients.

Prognostic value of microRNAs in hepatocellular carcinoma: a meta-analysis

Background

Numerous articles reported that dysregulated expression levels of miRNAs correlated with survival time of HCC patients. However, there has not been a comprehensive meta-analysis to evaluate the accurate prognostic value of miRNAs in HCC.

Design

Meta-analysis.

Materials and Methods

Studies, published in English, estimating expression levels of miRNAs with any survival curves in HCC were identified up until 15 April, 2017 by performing online searches in PubMed, EMBASE, Web of Science and Cochrane Database of Systematic Reviews by two independent authors. The pooled hazard ratios (HR) with 95% confidence intervals (CI) were used to estimate the correlation between miRNA expression and overall survival (OS).

Results

54 relevant articles about 16 miRNAs, with 6464 patients, were ultimately included. HCC patients with high expression of tissue miR-9 (HR = 2.35, 95% CI = 1.46–3.76), miR-21 (HR = 1.76, 95% CI = 1.29–2.41), miR-34c (HR = 1.64, 95% CI = 1.05–2.57), miR-155 (HR = 2.84, 95% CI = 1.46–5.51), miR-221 (HR = 1.76, 95% CI = 1.02–3.04) or low expression of tissue miR-22 (HR = 2.29, 95% CI = 1.63–3.21), miR-29c (HR = 1.35, 95% CI = 1.10–1.65), miR-34a (HR = 1.84, 95% CI = 1.30–2.59), miR-199a (HR = 2.78, 95% CI = 1.89–4.08), miR-200a (HR = 2.64, 95% CI = 1.86–3.77), miR-203 (HR = 2.20, 95% CI = 1.61–3.00) have significantly poor OS (P < 0.05). Likewise, HCC patients with high expression of blood miR-21 (HR = 1.73, 95% CI = 1.07–2.80), miR-192 (HR = 2.42, 95% CI = 1.15–5.10), miR-224 (HR = 1.56, 95% CI = 1.14–2.12) or low expression of blood miR-148a (HR = 2.26, 95% CI = 1.11–4.59) have significantly short OS (P < 0.05).

Conclusions

In conclusion, tissue miR-9, miR-21, miR-22, miR-29c, miR-34a, miR-34c, miR-155, miR-199a, miR-200a, miR-203, miR-221 and blood miR-21, miR-148a, miR-192, miR-224 demonstrate significantly prognostic value. Among them, tissue miR-9, miR-22, miR-155, miR-199a, miR-200a, miR-203 and blood miR-148a, miR-192 are potential prognostic candidates for predicting OS in HCC.

TRIM65 triggers β-catenin signaling via ubiquitylation of Axin1 to promote hepatocellular carcinoma

Deregulation of ubiquitin ligases contributes to the malignant progression of human cancers. Tripartite motif-containing protein 65 (TRIM65) is an E3 ubiquitin ligase and has been implicated in human diseases, but its role and clinical significance in hepatocellular carcinoma (HCC) remain unknown. Here, we showed that TRIM65 expression was increased in HCC tissues and associated with poor outcome in two independent cohorts containing 888 patients. In vitro and in vivo data demonstrated that overexpression of TRIM65 promoted cell growth and tumor metastasis, whereas knockdown of TRIM65 resulted in opposite phenotypes. Further studies revealed that TRIM65 exerted oncogenic activities via ubiquitylation of Axin1 to activate the β-catenin signaling pathway. TRIM65 directly bound to Axin1 and accelerated its degradation through ubiquitylation. Furthermore, HMGA1 was identified as an upstream regulator of TRIM65 in HCC cells. In clinical samples, TRIM65 expression was positively correlated with the expression of HMGA1 and nuclear β-catenin. Collectively, our data indicate that TRIM65 functions as an oncogene in HCC. The newly identified HMGA1/TRIM65/β-catenin axis serves as a promising prognostic factor and therapeutic target.

MiR-1202 functions as a tumor suppressor in glioma cells by targeting Rab1A

Aberrant expression of microRNAs correlates with the development and progression of human cancers by targeting downstream proteins. MiR-1202 is downregulated in ovarian cancer and clear cell papillary renal cell carcinoma; however, its role in glioma remains unknown. The purpose of this study was to determine the expression and the role of miR-1202 and to elucidate its regulatory mechanism in glioma. We used quantitative real-time polymerase chain reaction to measure miR-1202 expression in both glioma tissues and cell lines. The findings showed that the miR-1202 expression decreased dramatically in clinical glioma tissues and cell lines, and miR-1202 expression was inversely correlated with the expression of Rab1A. Using bioinformatics and luciferase reporter assays, we identified Rab1A as a novel and direct target of miR-1202. In vitro, overexpression of miR-1202 inhibited glioma cell proliferation and induced endoplasmic reticulum stress and apoptosis through targeting Rab1A, whereas suppression of miR-1202 promoted cell proliferation and inhibited endoplasmic reticulum stress and apoptosis. Similarly, silencing Rab1A with small interfering RNA also suppressed glioma cell growth and induced endoplasmic reticulum stress and apoptosis. Taken together, our data indicate that miR-1202 suppresses proliferation and induces endoplasmic reticulum stress and apoptosis through targeting and inhibiting Rab1A in glioma cells. These results suggest miR-1202 as a potential therapeutic target for the treatment of glioma patients.

miR-634 exhibits anti-tumor activities toward hepatocellular carcinoma via Rab1A and DHX33

Deregulation of microRNAs contributes to the aberrant growth of hepatocellular carcinoma (HCC). Here, we showed that miR-634 expression was frequently decreased in HCC. Low miR-634 expression was significantly associated with larger tumor size, poorer tumor differentiation, advanced TNM stage, vascular invasion, absence of tumor capsule and unfavorable overall survival. Overexpression of miR-634 markedly attenuated cell viability, colony formation, tumor growth and metastasis, whereas miR-634 inhibition resulted in the opposite phenotypes. Furthermore, re-introduction of miR-634 induced cell apoptosis in vitro and in vivo. Mechanistically, miR-634 inhibited the expression of Rab1A and DHX33 via directly binding to the 3'-UTR of both genes. In clinical samples, the expression of Rab1A or DHX33 was reversely correlated with miR-634. Re-expression of Rab1A or DHX33 abrogated the miR-634-mediated inhibition of cell proliferation and migration. Collectively, our data suggest a tumor suppressor role of miR-634 in HCC. The newly identified miR-634/Rab1A or miR-634/DHX33 axis serves as a potential therapeutic target for the clinical management.