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Lung adenocarcinoma (LUAD) emerges as one of the most lethal malignant tumors worldwide. Platinum-based combination chemotherapy remains one of the main methods for patients with advanced LUAD. Due to the resistance, the effect of this chemotherapy was not satisfactory. Therefore, studying the mechanism of cisplatin (DDP) resistance is essential for promoting the effect of this therapeutic strategy. Therefore, this work sought to probe the impact of E2F Transcription Factor 7 (E2F7) on LUAD resistance and the molecular regulatory mechanism. The mRNA expression level of the target gene E2F7 in LUAD was predicted by bioinformatics analysis, and regulatory miRNA upstream of the target gene was identified. The mRNA and protein expression of E2F7 in LUAD cells was detected through quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and Western blot, respectively. The expression of miR-195-5p in LUAD cells was measured via qRT-PCR. E2F7 high and low expression groups underwent enrichment analysis by utilizing Gene Set Enrichment Analysis software. The targeting relationship of miR-195-5p and E2F7 was validated by conducting a dual-luciferase reporter assay. The cell viability was tested through cell counting kit-8. The cell cycle was examined by flow cytometry. DNA damage level was determined via Comet assay and Western blot assay. The findings indicated that the mRNA and protein levels of E2F7 were high in LUAD. MiR-195-5p was the regulatory miRNA upstream of E2F7, and lowly expressed in LUAD. The cell experiments suggested that E2F7 advanced the DDP resistance of LUAD cells by repressing DNA damage. Finally, the rescue assay manifested that miR-195-5p overexpression could abate inhibition of E2F7 overexpression on the DNA damage and the DDP sensitivity of LUAD cells. MiR-195-5p raised the DDP sensitivity of LUAD cells by advancing the DNA damage in LUAD cells via inhibition of E2F7., (© 2024 Wiley Periodicals LLC.)

Background: Circular RNAs (circRNAs) are capable of affecting breast cancer (BC) development. However, the role and underneath mechanism of circFKBP8 (also known as hsa_circ_0000915) in BC remain largely unknown., Methods: Expression analyses were performed using quantitative real-time polymerase chain reaction (qRT-PCR), western blot, and immunohistochemistry (IHC) assays. Effects on cell functional phenotypes were determined by assessing cell proliferation, migratory capacity, invasion, and stemness in vitro. The relationship between microRNA (miR)-432-5p and circFKBP8 or E2F transcription factor 7 (E2F7) was examined by RNA pull-down, dual-luciferase reporter, and RNA immunoprecipitation (RIP) assays. Xenograft assays were used to identify the function of circFKBP8 in vivo., Results: CircFKBP8 was presented at high levels in BC tissues and cells. High circFKBP8 expression was associated with worse overall survival in BC patients. CircFKBP8 suppression inhibited BC cell proliferation, migratory capacity, invasion and stemness in vitro. CircFKBP8 suppression blocked xenograft tumor growth in vivo. Mechanistically, circFKBP8 functioned as a miR-432-5p sponge to modulate E2F7 expression. CircFKBP8 modulated BC cell malignant behaviors by miR-432-5p, and miR-432-5p affected these cell phenotypes through E2F7., Conclusion: Our observations prove that circFKBP8 promotes BC malignant phenotypes through the miR-432-5p/E2F7 cascade, offering a promising therapeutic and prognostic target for BC., (© 2024. The Author(s).)

Background: Adriamycin resistance remains an obstacle to gastric cancer chemotherapy treatment. Objective: The objective of this study was to study the role and mechanism of transcription factor E2F7 in sensitivity to ADM chemotherapeutic agents in gastric cancer., Methods: Cell viability and cell sensitivity were assessed by CCK-8 and IC50 values of ADM were calculated. The impact of ADM on cellular proliferative capacity was assessed through colony formation assay. The binding relationship between E2F7 and PKMYT1 was then verified by dual luciferase assay and chromatin immunoprecipitation assay. ERK1/ERK2 and p-ERK1/p-ERK2 protein expression levels were detected by western blot., Results: In both gastric cancer tissue and ADM-resistant cells, a conspicuous upregulation of E2F7 and PKMYT1 was observed. Upregulated PKMYT1 was notably enriched in the MAPK signaling pathway. Enhanced levels of E2F7 were shown to not only drive gastric cancer cell proliferation but also engender a reduction in the sensitivity of these cells to ADM. Furthermore, PKMYT1 emerged as a downstream target of E2F7. Activation of E2F7 culminated in the transcriptional upregulation of PKMYT1, and silencing E2F7 reversed the inhibitory impact of PKMYT1 overexpression on ADM sensitivity in gastric cancer cells., Conclusion: E2F7/PKMYT1 axis might promote the proliferation and partially inhibit ADM sensitivity of gastric cancer cells by activating the MAPK pathway.

Lung adenocarcinoma (LUAD) is a common malignancy. Many studies have shown that LUAD is resistant to gemcitabine chemotherapy, resulting in poor treatment outcomes in patients. We designed this study to reveal influences of hsa-miR-195-5p/E2F7/CEP55 axis on gemcitabine resistance and autophagy of LUAD cells. The expression data of LUAD-related mRNAs were downloaded from TCGA-LUAD database for differential expression analysis. The bioinformatics databases (hTFtarget, starBase and TargetScan) were used to predict the upstream and downstream regulatory molecules of E2F7. Then the binding relationships between E2F7 and regulatory molecules were verified by ChIP and dual-luciferase reporter assay. qRT-PCR and western blot were used to detect the mRNA and protein levels of has-miR-195-5p, E2F7, and CEP55. CCK-8 assay was used to analyze the half-maximal inhibitory concentration (IC 50 ) and cell proliferation ability of LUAD cells after gemcitabine treatment. Apoptosis was detected by flow cytometry. Apoptosis/autophagy markers and LC3 aggregation were detected by western blot and immunofluorescence, respectively. Finally, the mouse transplantation model was constructed to verify the regulation mechanism in vivo. In LUAD cells and tissues, E2F7 and CEP55 were highly expressed, while has-miR-195-5p was relatively less expressed. The ChIP or dual-luciferase assays demonstrated the binding relationships of E2F7 to the CEP55 promoter region and has-miR-195-5p to the 3'-UTR of E2F7. Cell experiments demonstrated that overexpression of hsa-miR-195-5p stimulated LUAD cell apoptosis and inhibited autophagy and gemcitabine resistance, while further overexpression E2F7/CEP55 could reverse the impact by hsa-miR-195-5p overexpression. In vivo experiments identified that hsa-miR-195-5p/E2F7/CEP55 axis constrained the growth of LUAD tumor. Hsa-miR-195-5p promoted apoptosis, repressed proliferation, and autophagy via E2F7/CEP55 and reduced gemcitabine resistance in LUAD, indicating that hsa-miR-195-5p/E2F7/CEP55 may be a novel target for LUAD., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Cisplatin (DDP) treatment is one of the most predominant chemotherapeutic strategies for lung cancer patients. Circular RNAs (circRNAs) have been revealed to participate in the chemoresistance in lung cancer. Hence, the role and mechanism of circ_0010235 in cisplatin resistance in lung cancer was investigated., Methods: Expression levels of circ_0010235, microRNA (miR)-379-5p and E2F transcription factor 7 (E2F7) were analyzed using quantitative reverse transcription PCR (qRT-PCR) and western blot. Cell DDP sensitivity, proliferation, apoptosis, invasion, and migration were detected by cell counting kit-8 assay, 5-ethynyl-2'-deoxyuridine (EDU) assay, flow cytometry and western blot, respectively. The binding interaction was verified using dual-luciferase reporter assay. A murine xenograft model was established to investigate effects in vivo., Results: Circ_0010235 was highly expressed in DDP-resistant lung cancer tissues and cells. Knockdown of circ_0010235 elevated DDP sensitivity, constrained proliferation, invasion and migration as well as fostered apoptosis in DDP-resistant lung cancer cells. Moreover, circ_0010235 silencing boosted DDP sensitivity and impeded tumor growth in lung cancer in vivo. Mechanistically, circ_0010235 acted as a sponge for miR-379-5p to elevate the expression of its target E2F7. Rescue experiments showed that miR-379-5p inhibition attenuated circ_0010235 knockdown-evoked reduction on DDP resistance of DDP-resistant cancer cells. In addition, miR-379-5p re-expression elevated DDP sensitivity and suppressed the malignant phenotype of DDP-resistant lung cancer cells through miR-379-5p., Conclusion: Circ_0010235 knockdown reduced DDP resistance and tumor growth via miR-379-5p/ E2F7 axis in lung cancer, suggesting an effective therapeutic target for lung cancer patients., (© 2023 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.)

Background: Accumulating genetic and epigenetic alterations in multiple myeloma (MM) have been demonstrated to be closely associated with osteolytic bone disease, generally characterized as increased osteoclast formation and decreased osteoblast activity. Previously, serum long non-coding RNA (lncRNA) H19 has been proved to be a biomarker for the diagnosis of MM. Whereas, its role in MM-associated bone homeostasis remains largely elusive., Methods: A cohort of 42 MM patients and 40 healthy volunteers were enrolled for evaluating differential expressions of H19 and its downstream effectors. The proliferative capacity of MM cells was monitored by CCK-8 assay. Alkaline phosphatase (ALP) staining and activity detection, either with Alizarin red staining (ARS) were employed to assess osteoblast formation. Osteoblast- or osteoclast-associated gene were detected using qRT-PCR and western blot analysis. Bioinformatics analysis, RNA pull-down, RNA immunoprecipitation (RIP), and chromatin immunoprecipitation (ChIP) were subjected to verify H19/miR-532-3p/E2F7/EZH2 axis, which was accounted for epigenetic suppression of PTEN. The functional role of H19 on MM development through unbalancing osteolysis and osteogenesis was also confirmed in the murine MM model., Results: Upregulation of serum H19 was observed in MM patients, suggesting its positive correlation with the poor prognosis of MM patients. Loss of H19 dramatically weakened cell proliferation of MM cells, promoted osteoblastic differentiation, and impaired osteoclast activity. While reinforced H19 exhibited the opposite effects. Akt/mTOR signaling plays an indispensable role in H19-mediated osteoblast formation and osteoclastgenesis. Mechanistically, H19 served as a sponge for miR-532-3p to upregulate E2F7, a transcriptional activator of EZH2, thereby accounting for modulating epigenetic suppression of PTEN. The in vivo experiments further validated that H19 exerted important impacts on tumor growth through breaking the balance between osteogenesis and osteolysis via Akt/mTOR signaling., Conclusion: Collectively, increased enrichment of H19 in MM cells exhibits an essential role in MM development by disturbing bone homeostasis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

E2F family participates in most human malignancies by activating the transcription of the cell cycle-related genes. Whereas, as a specifical atypical member of this family, E2F7 was described as a repressor against its downstream genes and exerted oscillatory and controversial functions in cancers. Our previous study identified a molecular interaction promoting hepatocellular carcinoma (HCC) growth induced by SOX4 and Anillin. Meanwhile, we preliminarily identified SP1 as the upstream activator of SOX4. Intriguingly, we observed that the repressive E2F7 presents a remarkable high expression in HCC, and is positively correlated and involved in the same pathway with the potentially SP1/SOX4/Anillin axis. However, their exact interaction or mechanism controlling tumor progress between these genes has not been illustrated. Thus, we focused on this point in this study and attempted to improve the potential regulating axis in HCC cell proliferation and tumor growth for promoting tumor prevention and control. The expression profile of E2F7 in HCC tissues and tumor cells was detected along with the related candidate genes, through real-time quantitative polymerase chain reaction assay, the Western blot analysis, and the immunohistochemistry assay, combined with bioinformatics analysis of the HCC information from the the Cancer Genome Altas and Gene Expression Omnibus data sets. The correlation between E2F7 and HCC patients' clinicopathologic features was explored. Gain-of and loss-of-function assays were conducted both in vitro and in vivo along with the rescue experiment, for revealing the relative genes' functions in HCC progress. The ChIP and the dual-luciferase reporter assays were performed to verify the transcriptional regulating profile between E2F7 and SP1/SOX4/Anillin axis. E2F7 was upregulated in HCC and significantly correlated with SP1/SOX4/Anillin axis. High E2F7 expression is associated with dismal clinicopathologic features and poor survival of the patients. E2F7 depletion potently impaired SP1/SOX4/Anillin expression and significantly inhibited HCC growth. Furthermore, intensive exploration demonstrated that E2F7 preserves high SP1 levels by abrogating miR-383-5p in a transcriptional way. Atypical E2F7 is an important repressive transcription factor commonly upregulated in the HCC environment. E2F7 facilitates HCC growth by repressing miR-383-5p transcription and sequentially promoting SP1/SOX4/Anillin axis. Our findings provide us with probable targets for HCC prevention and therapeutic treatment., (© 2022 The Authors. Molecular Carcinogenesis published by Wiley Periodicals LLC.)

Introduction: The paper aimed to explore the mechanism of miR-137 in modulating glioma., Material and Methods: qRT-PCR detected miR-137 and E2F7 mRNA expression in cells. The protein expression of E2F7 was measured using Western blot assay. Cell proliferation, scratch healing, transwell and programmed cell death assays were conducted to examine the influences of the genes on the biological function of glioma cells. The dual-luciferase assay verified the interaction between miR-137 and E2F7., Results: MiR-137 was lowly expressed in glioma cells, and E2F7 was highly expressed. MiR-137 suppressed progression and promoted programmed cell death of glioma cells. MiR-137 could target and negatively regulate E2F7 expression to further accelerate programmed cell death of glioma cells., Conclusions: It was found that miR-137 could target E2F7 to restrain cell progression and accelerate programmed cell death of glioma cells, which is helpful to search for new molecular therapeutic targets for glioma.

The literature indicates that LINC00174 promotes the growth of colorectal cancer (CRC) cells, but its research needs to be enriched. We tried to explore the function and mechanism of LINC00174 in CRC cell proliferation and migration. Bioinformatics analysis predicted the binding relationship and expressions of lncRNA, miRNA and mRNA. Clinical study analyzes the relationship between LINC00174 and clinical data characteristics of CRC patients. The expressions of LINC00174, miR-3127-5p and E2F7 were verified by RT-qPCR, and the combination of the two was verified by dual luciferase analysis and RNA immunoprecipitation as needed. Western blot was used to detect the expression of EMT-related protein and E2F7 protein. Functional experiments were used to evaluate the function of the target gene on CRC cells. LINC00174 was up-regulated in CRC clinical samples and cells and was related to the clinical characteristics of CRC patients. High-expression of LINC00174, contrary to the effect of siLINC00174, promoted cell viability, proliferation, migration and invasion, up-regulated the expressions of N-Cadherin, Vimentin, E2F7, and inhibited the expression of E-Cadherin. MiR-3127-5p was one of the targeted miRNAs of LINC00174 and was down-regulated in CRC samples. In addition, miR-3127-5p mimic partially reversed the malignant phenotype of CRC cells induced by LINC00174. Besides, E2F7 was a target gene of miR-3127-5p, and LINC00174 repressed miR-3127-5p to regulate E2F7. Our research reveals that LINC00174 affected the biological characteristics of CRC cells through regulated miR-3127-5p/ E2F7 axis.

Background: Increasing biomolecules have been found to be involved in the lung cancer development. This study will perform the function and mechanism analyses of a novel circular RNA copper chaperone for superoxide dismutase (circ-CCS) in lung cancer., Methods: Circ-CCS, microRNA-383 (miR-383) and E2F transcription factor 7 (E2F7) were quantified by quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability was detected using Cell Counting Kit-8 (CCK-8). Clonal ability was measured by colony formation assay. Cell apoptosis was determined via flow cytometry. Cell migration and invasion were assessed by transwell assay. Detection of protein was completed using western blot. Xenograft assay was used for the functional analysis of circ-CCS in vivo. The binding between targets was proved by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. E2F7 protein level was also examined by Immunohistochemistry (IHC) analysis in human tissues., Results: Circ-CCS was upregulated in lung cancer and could predict poor prognosis. Downregulation of circ-CCS inhibited lung cancer cell growth and metastasis while promoted apoptosis in vitro, and suppressed tumorigenesis of lung cancer in vivo. Circ-CCS had sponge effect on miR-383 and the function of si-circ-CCS was achieved by upregulating miR-383. E2F7 was a target gene of miR-383 and its downregulation was responsible for the anti-cancerous role of miR-383 in lung cancer. Circ-CCS could elevate E2F7 expression via interacting with miR-383., Conclusion: Circ-CCS was shown to facilitate lung cancer progression via the miR-383/E2F7 axis, exhibiting the pivotal value of circ-CCS in diagnosis and treatment of lung cancer., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Long non-coding RNAs (lncRNAs) are crucial in the invasion, angiogenesis, progression, and metastasis of hepatocellular carcinoma (HCC). The lncRNA MYLK-AS1 promotes the growth and invasion of HCC through the EGFR/HER2-ERK1/2 signaling pathway. However, the clinical significance of MYLK-AS1 in HCC still needs to be further determined., Methods: Bioinformatic analysis was performed to determine the potential relationship among MYLK-AS1, miRNAs and mRNAs. A total of 156 samples of normal liver and paired HCC tissues from HCC patients were used to evaluate MYLK-AS1 expression by qRT-PCR. Human HCC cell lines were used to evaluate the colony formation, cell proliferation, migration, invasion, cell cycle and apoptosis after transfection of lentiviral short-hairpin RNAs (shRNAs) targeting MYLK-AS1 or MYLK-AS1 vectors. The competitive endogenous RNA (ceRNA) mechanism was clarified using fluorescence in situ hybridization (FISH), Western blotting, qPCR, RNA binding protein immunoprecipitation (RIP), and dual luciferase reporter analysis., Results: MYLK-AS1 up-regulation was detected in the HCC tumor tissues and cell lines associated with the enhancement of the angiogenesis and tumor progression. The down-regulation of MYLK-AS1 reversed the effects on angiogenesis, proliferation, invasion and metastasis in the HCC cells and in vivo. MYLK-AS1 acted as ceRNA, capable of regulating the angiogenesis in HCC, while the microRNA miR-424-5p was the direct target of MYLK-AS1. Promoting the angiogenesis and the tumor proliferation, the complex MYLK-AS1/miR-424-5p activated the VEGFR-2 signaling through E2F7, whereas the specific targeting of E2F transcription factor 7 (E2F7) by miR-424-5p, was indicated by the mechanism studies., Conclusions: MYLK-AS1 and E2F7 are closely related to some malignant clinicopathological features and prognosis of HCC, thus the MYLK-AS1/ miR-424-5p/E2F7 signaling pathway might represent a promising treatment strategy to combat HCC.

Background: Abnormal microRNAs (miRNAs) expression is closely related to the development and poor prognosis of pancreatic ductal adenocarcinoma (PDAC). We aimed to elucidate the invasive mechanism and clinical significance of miR-10b in PDAC., Methods: The RNA sequence data of pancreatic cancer were extracted from the TCGA database. R packages were performed to analyze the differential expression of RNAs. TargetScan, picTar, and miRanda were used to predict the target gene of miRNA. The expression level of the selected candidate was tested by western blot and RT-PCR in PDAC cells and tissues. Scrape and Transwell assays were determined the effect of candidate molecules on cell migration and invasion. The gain of function and loss of function was achieved by co-culture with mimics and vector. Luciferase reporters were generated based on the psiCHECK2 vector. The relative luciferase activity was measured with the Dual-Luciferase Reporter Assay System and Infinate M200 PRO microplate reader., Results: Based on the TCGA data and bioinformatics analysis, we obtained seven differentially expressed miRNAs. Both TCGA data and our center clinical date indicated that miR-10b was contributed to the poor survival of PDAC. Based on the target gene prediction database, we found that E2F7 was a target mRNA of miR-10b. In subsequent experiments in molecular biology, miR-10b expression was downregulated in PDAC cells and tissues, while E2F7 was upregulated. Scrape and Transwell assay indicated that miR-10b could inhibit the invasion and migration of PDAC. MiR-10b was confirmed to be by the E2F7 targeting site by dual-luciferase report. Moreover, rescue experiments prove that miR-10b could inhibit the invasion and migration of PDAC cells by regulating E2F7 expression., Conclusion: Our results suggest that miR-10b could inhibit the progression of PDAC by regulating E2F7 expression and acts as an independent prognostic risk factor for PDAC., (© 2020 The Authors. Journal of Clinical Laboratory Analysis published by Wiley Periodicals LLC.)

microRNAs (miRNAs), a kind of small noncoding RNAs, are considered able to regulate expression of genes and mediate RNA silencing. miR-129-5p was shown to be a cancer-related miRNA. However, the influence of miR-129-5p in rectal adenocarcinoma (READ) development remains to be determined. Based on the TCGA data, downregulation of miR-129-5p in READ samples was observed. Manual restoration of the miR-129-5p in SW1463 and SW480 cell lines significantly inhibited invasion, migration, and proliferation of READ cell lines, while the apoptosis ability was enhanced. Meanwhile, we found E2F7 acted as a potential target of miR-129-5p and was upregulated in READ samples. E2F7 upregulation reversed the repression of miR-129-5p on READ development. Finally, in vivo experiments showed that inhibition of tumor growth in nude mice was achieved through upregulating miR-129-5p. Overall, our findings suggest increasing of miR-129-5p leads to the suppression of READ progression through regulating the expression of E2F7, which may provide novel insights into the treatment of READ., (© 2020 Wiley Periodicals, Inc.)

Background: Emerging evidences have proven the important roles of lncRNAs in tumorigenesis and cancer biology. However, the function of lncRNA DLEU2 in the progression of esophageal cancer (EC) has not been elaborated. In the present study, we aimed to investigate the effects of lncRNA DLEU2 on the progression of EC and the underlying mechanism., Methods: In this study, lncRNA DLEU2 was silenced by siRNA interference in EC cell lines Eca-109 and KYSE-150, and its expression was up-regulated in TE-1 cells by transfection with pcDNA3.1-DLEU2, and its biological functions were examined. Then, bioinformatics analysis and dual-luciferase reporter assay were used to identify the binding miRNA of lncRNA DLEU2 and the target gene of miRNA. In addition, loss-of-function assays were performed to detect the biological functions of the target gene. At last, the rescue assays were used to investigate the relationship among lncRNA DLEU2, miRNA and target gene., Results: With the help of GEPIA analysis, we observed that lncRNA DLEU2 was up-regulated in EC tissues and associated with poor prognosis. Loss-of-function assay showed that silencing lncRNA DLEU2 inhibited the proliferation, migration and invasion of EC cells, and induced apoptosis by regulating the Bcl-2/Bax axis and Caspase cascade. Overexpression of lncRNA DLEU2 increased the proliferation, migration and invasion abilities of TE-1 cells, as well as decreased cell apoptosis. Bioinformatics analysis and dual-luciferase reporter assay verified that miR-30e-5p could directly bind with lncRNA DLEU2, and E2F7 was a direct target for miR-30e-5p in EC cells. Moreover, our data revealed that silencing E2F7 decreased the proliferation, migration and invasion abilities of EC cells, and induced apoptosis. Furthermore, the rescue assays demonstrated that the effects of lncRNA DLEU2 on the proliferation, migration and invasion of EC cells were reversed by miR-30e-5p inhibitor or up-regulation of E2F7., Conclusions: Our findings revealed the pro-oncogenic role of lncRNA DLEU2 and E2F7 in the progression of EC, suggesting that lncRNA DLEU2 exerts ceRNA functions in EC through regulating miR-30e-5p/E2F7 axis., Competing Interests: Declaration of Competing Interest The authors confirm that there are no any conflicts of interest., (Copyright © 2019 The Author(s). Published by Elsevier Masson SAS.. All rights reserved.)

Excessive oxidative stress induces significant injury and cytotoxicity to neuronal cells. The current study tested expression and the potential function of the circular RNA PRKCI (circPRKCI) in oxidative stress-injured neuronal cells. In cultured SH-SY5Y neuronal cells, hydrogen peroxide (H 2 O 2 ) downregulated circPRKCI expression, causing accumulation of miR-545 and miR-589, but reduction of their target, the transcription factor E2F7. Importantly, ectopic overexpression of circPRKCI in SH-SY5Y cells significantly attenuated H 2 O 2 -induced cytotoxicity. Conversely, siRNA-mediated knockdown of circPRKCI induced SH-SY5Y cell death and apoptosis. Further studies demonstrated that H 2 O 2 -induced cytotoxicity in SH-SY5Y cells was inhibited by miR-545/589 inhibitors, but mimicked by miR-545/589 mimics. Importantly, CRISPR/Cas9-mediated knockout (KO) of E2F7 induced potent SH-SY5Y cell death and apoptosis. Furthermore, transfection of circPRKCI siRNA or miR-545/589 mimics were ineffective in E2F7 KO cells. In the primary human neurons, H 2 O 2 stimulation similarly induced circPRKCI downregulation, miR-545/589 accumulation and E2F7 reduction. Moreover, H 2 O 2 -induced death and apoptosis in the primary neurons were significantly inhibited by circPRKCI overexpression or miR-545/589 inhibitors. Taken together, our results show that dysregulation of circPRKCI-miR-545/589-E2F7 axis mediated H 2 O 2 -induced neuronal cell injury. Targeting this novel cascade could be a fine strategy to protect neurons from oxidative stress., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: A potential role for microRNA-935 (miR-935) has been identified in several cancers but not in non-small cell lung cancer (NSCLC). We hypothesised changes in miR-935 in NSCLC, and proposed mechanisms that may further explain its role in carcinogenesis., Methods: NSCLC tissue and nearby normal tissue was obtained from 101 patients and was probed by qRT-PCR for miR-935 expression. The role of miR-935 and a potential target (signal transduction factor E2F7) was determined in cell lines by a dual luciferase assay. The function of miR-935 was investigated through metabolic activity (MTT) and transwell migration assays. Western blot and immunocytochemical assays examined protein expression level. Growth of miR-935 transfected or untransfected cells was measured via xenograft tumour formation., Results: miR-935 was reduced in cancer tissue and was related to lymph node metastases, tumour node metastasis status and poor prognosis (all p < 0.02). In vitro, miR-935 suppressed cell proliferation, migration and invasion in NSCLC cells through targeting E2F7. Furthermore, E2F7 was upregulated in NSCLC tissue associated with poor prognosis (p = 0.0203) of NSCLC patients. miR-935 suppressed the epithelial-mesenchymal transition and AKT pathways in NSCLC and inhibited the tumour growth in vivo., Conclusion: Altered miR-935 in lung cancer biopsy tissue may be a diagnostic tool and could direct treatment. Involvement in carcinogenesis is implied by its suppression of the development of NSCLC via targeting E2F7 and inhibiting AKT pathway.

Background: There is increasing evidence that liver cancer stem cells (LCSCs) contribute to hepatocellular carcinoma (HCC) initiation and progression. MicroRNA (miRNA) plays a significant functional role by directly regulating respective targets in LCSCs-triggered HCC, however, little is known about the function of the miRNA-302 family in LCSCs., Methods: MiRNAs microarray was used to detect the miRNAs involved in LCSCs maintenance and differentiation. Biological roles and the molecular mechanism of miRNA-302a/d and its target gene E2F7 were detected in HCC in vitro. The expression and correlation of miRNA-302a/d and E2F7 in HCC patients was evaluated by quantitative PCR and Kaplan-Meier survival analysis., Results: We found that the miRNA-302 family was downregulated during the spheroid formation of HCC cells and patients with lower miRNA-302a/d expression had shorter overall survival (OS) and progression-free survival (PFS). Moreover, E2F7 was confirmed to be directly targeted and inhibited by miRNA-302a/d. Furthermore, concomitant low expression of miRNA-302a/d and high expression of E2F7 correlated with a shorter median OS and PFS in HCC patients. Cellular functional analysis demonstrated that miRNA-302a/d negatively regulates self-renewal capability and cell cycle entry of liver cancer stem cells via suppression of its target gene E2F7 and its downstream AKT/β-catenin/CCND1 signaling pathway., Conclusions: Our data provide the first evidence that E2F7 is a direct target of miRNA-302a/d and miRNA-302a/d inhibits the stemness of LCSCs and proliferation of HCC cells by targeting the E2F7/AKT/β-catenin/CCND1 signaling pathway.

Objective: Colorectal cancer (CRC) is one of the most common malignancies with high morbidity and mortality rates worldwide. This study aimed to investigate whether miR-3666 was involved in inhibitory effects of all-transretinoic acid (ATRA) on the development of colorectal cancer (CRC)., Material and Methods: Surgical specimens of CRC tissues and adjacent non-tumor mucosa were collected for determining miR-3666 expression. Human CRC HCT116 cells were treated with different doses of ATRA (10, 20, 40, and 60 μM, respectively) and/or transfected with miR-3666 mimic, miR-3666 inhibitor, E2F7 siRNAs or their controls, respectively. After different treatments, cell viability, apoptosis, migration and invasion were detected. The regulatory relationship between miR-3666 and E2F7 was investigated. Furthermore, the association between MAPK/ERK pathway and ATRA or miR-3666/E2F7 was explored., Results: The miR-3666 was lowly expressed in CRC tissues, while E2F7 was highly expressed. ATRA decreased HCT116 cell viability, migration, and invasion, and induced apoptosis, indicating that ATRA inhibited the malignant behaviors of HCT116 cells. Moreover, ATRA increased miR-3666 expression, and effects of ATRA on the malignant behaviors of HCT116 cells were achieved by positive regulating miR-3666 expression. Furthermore, E2F7 was a target gene of miR-3666, and knockdown of E2F7 reversed the combined effects of ATRA and miR-3666 inhibitor on the malignant behaviors of HCT116 cells. Besides, ATRA inhibited the activation of MAPK/ERK signaling pathway, which was reversed by inhibition of miR-3666., Conclusions: Our results reveal that ATRA protects against CRC development possible via increasing miR-3666 expression and decreasing E2F7 expression. MiR-3666/E2F7 may play a key role in regulating the inhibitory effects of ATRA on HCT116 cells via suppressing the activation of MAPK/ERK signaling pathway., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Abnormalities of autophagy have been implicated in an increasing number of human cancers, including glioma. To date, there is a wealth of evidence indicating that microRNAs (miRNAs) contribute significantly to autophagy in a variety of cancers. Previous studies have suggested that miR-129 functioned as an important inhibitor of the cell cycle and could promote the apoptosis of many cancer cell lines in vitro. Here, we reported that miR-129 acted as a potent inducer of autophagy. Forced expression of miR-129 could induce autophagic flux by targetedly suppressing Notch-1 in glioma cells. The autophagy induced by miR-129 could restrain the activity of mammalian target of rapamycin (mTOR) and upregulate Beclin-1. Moreover, we demonstrated that E2F transcription factor 7 (E2F7) could also trigger autophagic flux by upregulating Beclin-1 and mediating miR-129-induced autophagy. Additionally, knockdown of Notch-1 could upregulate the expression of E2F7, whereas downregulation of E2F7 alleviated shNotch-1-induced autophagic flux. In particular, knockdown of endogenous Beclin-1 could effectively reduce autophagic flux stimulated by miR-129 and E2F7. Interestingly, upon attenuation of miR-129- or E2F7-triggered autophagic flux rescued cell viability suppressed by them. More importantly, intratumoral injection of pHAGE-miR-129 lentivirus in a nude mouse xenograft model significantly restrained tumor growth and triggered autophagy. In conclusion, these findings identify a new function for miR-129 as a potent inducer of autophagy through a novel Notch-1/E2F7/Beclin-1 axis in glioma.

About 50-70% of breast cancers are estrogen receptor α (ERα) positive and most of them are sensitive to endocrine therapy including tamoxifen. However, one third of these patients will eventually develop resistance and relapse. We found that the expression of miR-15a and miR-16 were significantly decreased in tamoxifen resistant ER positive breast cancer cell lines. Exogenous expression of miR-15a/16 mimics re-sensitized resistant cells to tamoxifen by inhibiting Cyclin E1 and B cell lymphoma-2 (Bcl-2) to induce cell growth arrest and apoptosis respectively. Further, we identified that a repressive member of E2F family, E2F7, was responsible for the suppression of miR-15a/16 cluster by competing with E2F1 for E2F binding site at the promoter of their host gene DLEU2. Moreover, high expression of E2F7 is correlated with high risk of relapse and poor prognosis in breast cancer patients receiving tamoxifen treatment. Together, our results suggest that overexpression of E2F7 represses miR-15a/16 and then increases Cyclin E1 and Bcl-2 that result in tamoxifen resistance. E2F7 may be a valuable prognostic marker and a therapeutic target of tamoxifen resistance in breast cancer.