MiR-27a-3p enhances the cisplatin sensitivity in hepatocellular carcinoma cells through inhibiting PI3K/Akt pathway

MicroRNAs (miRNAs) play an important role in drug resistance, and it is reported that miR-27a-3p regulated the sensitivity of cisplatin in breast cancer, lung cancer and ovarian cancer. However, the relationship between miR-27a-3p and chemosensitivity of cisplatin in hepatocellular carcinoma (HCC) was unclear, especially the underlying mechanism was unknown. In the present study, we analyzed miR-27a-3p expression levels in 372 tumor tissues and 49 adjacent tissues in HCC samples from TCGA database, and found that the miR-27a-3p was down-regulated in HCC tissues. The level of miR-27a-3p was associated with metastasis, Child–Pugh grade and race. MiR-27a-3p was regarded as a favorable prognosis indicator for HCC patients. Then, miR-27a-3p was overexpressed in HepG2 cell, and was knocked down in PLC cell. Next, we conducted a series of in vitro assays, including MTT, apoptosis and cell cycle assays to observe the biological changes. Further, inhibitor rate and apoptosis rate were detected with pre- and post-cisplatin treatment in HCC. The results showed that overexpression of miR-27a-3p repressed the cell viability, promoted apoptosis and increased the percentage of cells in G₀/G₁ phase. Importantly, overexpression of miR-27a-3p significantly increased the inhibitor rate and apoptosis rate with cisplatin intervention. Besides, we found that miR-27a-3p added cisplatin sensitivity potentially through regulating PI3K/Akt signaling pathway. Taken together, miR-27a-3p acted as a tumor suppressor gene in HCC cells, and it could be useful for modulating cisplatin sensitivity in chemotherapy.     

microRNA-148a-3p enhances the effects of sevoflurane on hepatocellular carcinoma cell progression via ROCK1 repression

BackgroundSevoflurane (SEVO) inactivates the aggressiveness of hepatocellular carcinoma (HCC) cells by mediating microRNAs (miRNAs). Hence, we delved into the functional role of miR-148a-3p mediated by SEVO in HCC.MethodsLiver cells (L02) and HCC cells (HCCLM3 and Huh7) were exposed to SEVO to detect cell viability in HCC. HCCLM3 and Huh7 cells were treated with restored miR-148a-3p or depleted Rho-associated protein kinase 1 (ROCK1) to elucidate their roles in HCC cells' biological characteristics. HCCLM3 and Huh7 cells were treated with SEVO, and/or vectors that changed miR-148a-3p or ROCK1 expression to identify their combined functions in HCC cell progression. Tumor xenograft in nude mice was performed to determine growth ability of tumor. The target relationship between miR-148a-3p and ROCK1 was verified.ResultsSEVO inhibited proliferation, invasion and migration and enhanced apoptosis of HCCLM3 and Huh7 cells. MiR-148a-3p up-regulation or ROCK1 down-regulation inhibited HCCLM3 and Huh7 cell progression. ROCK1 was determined to be target gene of miR-148a-3p. Down-regulating miR-148a-3p or overexpressing ROCK1 mitigated cell aggressiveness inhibition caused by SEVO.ConclusionOur study elucidates that microRNA-148a-3p enhances the effects of sevoflurane on inhibiting proliferation, invasion and migration and enhancing apoptosis of HCC cells through suppression of ROCK1.     

Dependence of Intracellular and Exosomal microRNAs on Viral E6/E7 Oncogene Expression in HPV-positive Tumor Cells

Specific types of human papillomaviruses (HPVs) cause cervical cancer. Cervical cancers exhibit aberrant cellular microRNA (miRNA) expression patterns. By genome-wide analyses, we investigate whether the intracellular and exosomal miRNA compositions of HPV-positive cancer cells are dependent on endogenous E6/E7 oncogene expression. Deep sequencing studies combined with qRT-PCR analyses show that E6/E7 silencing significantly affects ten of the 52 most abundant intracellular miRNAs in HPV18-positive HeLa cells, downregulating miR-17-5p, miR-186-5p, miR-378a-3p, miR-378f, miR-629-5p and miR-7-5p, and upregulating miR-143-3p, miR-23a-3p, miR-23b-3p and miR-27b-3p. The effects of E6/E7 silencing on miRNA levels are mainly not dependent on p53 and similarly observed in HPV16-positive SiHa cells. The E6/E7-regulated miRNAs are enriched for species involved in the control of cell proliferation, senescence and apoptosis, suggesting that they contribute to the growth of HPV-positive cancer cells. Consistently, we show that sustained E6/E7 expression is required to maintain the intracellular levels of members of the miR-17~92 cluster, which reduce expression of the anti-proliferative p21 gene in HPV-positive cancer cells. In exosomes secreted by HeLa cells, a distinct seven-miRNA-signature was identified among the most abundant miRNAs, with significant downregulation of let-7d-5p, miR-20a-5p, miR-378a-3p, miR-423-3p, miR-7-5p, miR-92a-3p and upregulation of miR-21-5p, upon E6/E7 silencing. Several of the E6/E7-dependent exosomal miRNAs have also been linked to the control of cell proliferation and apoptosis. This study represents the first global analysis of intracellular and exosomal miRNAs and shows that viral oncogene expression affects the abundance of multiple miRNAs likely contributing to the E6/E7-dependent growth of HPV-positive cancer cells.     

Homoharringtonine inhibited breast cancer cells growth via miR-18a-3p/AKT/mTOR signaling pathway

Homoharringtonine (HHT), a natural alkaloid derived from the cephalotaxus, exhibited its anti-cancer effects in hematological malignancies clinically. However, its pesticide effects and mechanisms in treating solid tumors remain unclear. In this study, we found that HHT was capable of inhibiting tumor growth after 5-days treatment of breast cancer cells, MCF-7, in vivo. Furthemore, HHT also significantly inhibited the cancer cell growth and induced cell apoptosis in vitro. miRNA sequencing proved miR-18a-3p was noticeably downregulated in the cells after HHT treatment. Moreover, downregulating miR-18a-3p increased HHT-induced cell apoptosis; our data supported that HHT suppressed miR-18a-3p expression and inhibited tumorigenesis might via AKT-mTOR signaling pathway. In conclusion: our study proved that HHT suppressed breast cancer cell growth and promoted apoptosis mediated by regulating of the miR-18a-3p-AKT-mTOR signaling pathway, HHT may be a promising antitumor agent in breast cancer treatment.     

肝细胞癌患者血清外泌体microRNA表达鉴定

目的:探讨肝癌细胞外泌体中差异表达的microRNAs(miRNAs)在肝细胞癌(HCC)诊断中的应用价值。方法:通过高通量测序筛选肝癌细胞外泌体中差异表达的miRNAs。实时定量PCR验证差异表达分子;检测差异表达的miRNAs在健康人(Health)、慢性乙型肝炎患者(CHB)、肝硬化患者(LC)及乙型肝炎病毒阳性的肝细胞癌患者(HCC)血清外泌体中的表达。结果:高通量测序筛选到肝癌细胞外泌体中差异表达的miRNA共88种,其中58种表达上调,30种表达下调。选择其中8种差异表达的miRNAs进行q RT-PCR验证,结果显示,此8种miRNAs在细胞上清外泌体、细胞内、癌与癌旁组织中的表达趋势与测序结果一致。miR-221-3p和miR-224-5p在HCC组外泌体中的表达水平显著高于Health组、CHB组和LC组(P0.01),miR-124-3p和let-7a-5p在HCC组外泌体中的表达水平显著低于其他各组(P0.05)。四个组中,miR-21-5p、miR-191-5p、miR-34a-5p和miR-122-5p的表达水平不存在显著性差异(P0.05)。结论:血清外泌体中的miR-221-3p、miR-224-5p、miR-124-3p和let-7a-5p可能成为肝细胞癌的候选标志物。     

Licochalcone A reverses NNK-induced ectopic miRNA expression to elicit in vitro and in vivo chemopreventive effects

BackgroundChemoprevention is the best cost-effective way regarding cancers. MicroRNAs (miRNAs) have been reported to be differentially expressed during the development of lung cancer. However, if lung cancer prevention can be achieved through modulating miRNAs expression so far remains unknown.PurposeTo discover ectopically expressed miRNAs in NNK-induced lung cancer and clarify whether Licochalcone A (lico A) can prevent NNK-induced lung cancer by modulating miRNA expression.Study design and methodsA/J mice were used to construct a lung cancer model by intraperitoneal injection with physiological saline NNK (100 mg/kg). Chemopreventive effects of lico A against lung cancer at 2 mg/kg and 20 mg/kg doses were evaluated in vivo. MicroRNA array and RT-qPCR were used to assess the expression levels of miRNAs. MLE-12 cells were treated with 0.1 mg/ml NNK, stimulating the ectopic expression pattern of miR-144-3p, miR-20a-5p, miR-29c-3p, let-7d-3p, and miR-328-3p. miR-144-3p mimics and inhibitors were used to manipulate miR-144-3p levels. The effects of lico A (10 μM) on cell cycle distribution, apoptosis, and the expression of CK19, RASA1, miR-144-3p, miR-20a-5p, miR-29c-3p, let-7d-3p, and miR-328-3p in NNK-treated MLE-12 cells were studied.ResultsThe expression levels of miR-144-3p, miR-20a-5p, and miR-29c-3p increased, while those of let-7d-3p and miR-328-3p decreased in both NNK-induced A/J mice and MLE-12 cells. Lico A could reverse the NNK-induced ectopic miRNA (miR-144-3p, miR-20a-5p, miR-29c-3p, let-7d-3p, and miR-328-3p) expression both in vivo and in vitro and elicit in vivo lung cancer chemopreventive effect against NNK. In MLE-12 cells, the overexpression of miR-144-3p elicited the same effect as NNK regarding the expression of lung cancer biomarker CK19; the silencing of miR-144-3p reversed the effect of NNK on cell cycle distribution and apoptosis. Lico A could reverse the effect of NNK on the expression of miR-144-3p, CK19, and RASA1 (predicted target of miR-144-3p).ConclusionThe present study suggests that miR-144-3p, miR-20a-5p, miR-29c-3p, let-7d-3p, and miR-328-3p were involved in the in vivo pathogenesis of NNK-induced lung cancer, and lico A could reverse the effect of NNK both in vivo and in vitro to elicit lung cancer chemopreventive effects through, at least partially, these five ectopically expressed miRNAs, especially miR-144-3p.     

Bone marrow-derived mesenchymal stem cells repair severe acute pancreatitis by secreting miR-181a-5p to target PTEN/Akt/TGF-β1 signaling

BackgroundSevere acute pancreatitis (SAP) is associated with high morbidity and mortality. Bone marrow mesenchymal stem cells (BMSCs) have shown obvious protective effect on SAP. However, little is known about the underlying mechanism. The objective of this study is to unravel the role and regulatory mechanism of miR-181a-5p in BMSCs-mediated pancreatic repair.MethodsBMSCs were isolated from Sprague-Dawley rats and characterized by flow cytometry and Oil Red O staining. Sodium taurocholate- and caerulein-induced models were used as SAP models in vivo and in vitro, respectively. Pancreatic injury were evaluated by H&E and histopathological analysis, as well as by measuring levels of amylase, lipase and cytokines. qRT-PCR and western blotting were performed to detect the level of miR-181a-5p and the protein levels of PTEN/Akt, respectively. ELISA was conducted to detect the levels of TNF-α, IL-1β, IL-6, angiopoietin, IL-4, IL-10 and TGF-β1. The apoptotic rate of AR42 J cells was quantitated by concurrent staining with Annexin-V-FITC and PI.ResultsBMSCs significantly attenuated pancreatic injury in SAP rats by reducing inflammatory infiltration and necrosis, and this effect was abolished by CXCR4 agonist AMD3100. ADM3100 exhibited more severe pancreatic injury and decreased miR-181a-5p levels in the pancreas and serum compared to SAP group. Overexpression of miR-181a-5p in BMSCs (BMSCs-miR-181a-5p) markedly potentiated the protective effect of BMSCs by reducing histological damage and levels of amylase and lipase. Moreover, BMSCs-miR-181a-5p dramatically reduced levels of angiopoietin, TNF-α, IL-1β and IL-6, but induced the levels of IL-4 and IL-10. In caerulein-treated AR42 J cells, co-culturing of BMSCs-miR-181a-5p alleviated caerulein-induced increase of amylase and lipase, and apoptosis via PTEN/Akt/TGF-β1 signaling.ConclusionBMSCs alleviate SAP and reduce inflammatory responses and apoptosis by secreting miR-181a-5p to target PTEN/Akt/TGF-β1 signaling. Hence, BMSCs-miR-181a-5p could serve as potential therapeutic target for SAP.     

Protective effect of Idelalisib on carbon tetrachloride-induced liver fibrosis via microRNA-124-3P/phosphatidylinositol-3-hydroxykinase signalling pathway

Liver fibrosis is the repair process of abnormal connective tissue hyperplasia after liver damage caused by different causes. Inhibition of PI3K/Akt signalling pathway can reduce the deposition of extracellular matrix, inhibit the proliferation of hepatic stellate cells (HSCs), and promote its apoptosis to achieve the purpose of therapy. This study aimed to investigate the effect of Idelalisib (PI3K inhibitor) on carbon tetrachloride (CCl₄)-induced liver fibrosis in mice. We used CCl₄-induced liver fibrosis mouse model in vivo and TGF-β1-stimulated HSCs to evaluate the antifibrosis activity of Idelalisib. In vivo, Idelalisib significantly alleviated CCl₄-induced liver damage, collagen deposition, and hydroxyproline accumulation in mice. Immunohistochemistry and Western blot results showed that Idelalisib could significantly inhibit the expressions of COL1 and α-SMA in a concentration-dependent manner. In cell experiments, Idelalisib significantly inhibited the expressions of COL1, SMA, and p-Smad3 in TGF-β-induced HSCs, thereby inhibiting HSC activation. Flow cytometry and Western blot results showed that Idelalisib significantly promoted TGFβ-induced apoptosis of HSCs after 48 h of administration, but had no significant effect after 24 h. Idelalisib promoted the apoptosis of activated HSCs by inhibiting the PI3K/Akt/FOXO3 signalling pathway. To further explore the mechanism by which Idelalisib inhibited PI3K, we predicted the miRNA targeting PI3K through the database and crossed it with the down-regulated miRNA reported in liver fibrosis mice in the past five years. Finally, we identified miR-124-3p and miR-143-3p. We then demonstrated that Idelalisib significantly promoted miR-124-3p and miR-142-3p in vitro and in vivo. Dual-luciferase report analysis showed that Idelalisib significantly inhibited luciferase activity but had no significant effect on the luc-MUT transfection assay. Finally, we demonstrated that Idelalisib reversed the effects of miR-124-3p inhibitor on the PI3K/Akt/FOXO3 asterisk pathway and caspase-3. Idelalisib has potential as a candidate drug for alleviating liver fibrosis.     

In vitro and in vivo anti-metastatic effect of the alkaliod matrine from Sophora flavecens on hepatocellular carcinoma and its mechanisms

BackgroundsHepatocellular carcinoma (HCC) is one of the most prevalent and lethal cancer with high metastasis and recurrence rates. Hypoxia-induced miRNAs and HIF-1α are demonstrated to play essential roles in tumor metastasis. Matrine (C₁₅H₂₄N₂O), an alkaloid extracted from Sophora flavescens Aiton, has been used as adjuvant therapy for liver cancer in China. The anti-metastasis effects of matrine on HCC and the underlying mechanisms remain poorly understood.PurposeWe aimed to investigate the effects of matrine on metastasis of HCC both in vitro and in vivo, and explored whether miR-199a-5p and HIF-1α are involved in the action of matrine.MethodsMTT method, colony formation, wound healing and matrigel transwell assays were performed to evaluate the effects of matrine on cell proliferation, migration and invasion. Nude mice xenograft model and immunohistochemistry (IHC) assay were employed to investigate the anti-metastatic action of matrine in vivo. Quantitative real-time PCR, western blot and dual luciferase reporter assay were conducted to determine the underlying mechanisms of matrine.ResultsMatrine exerted stronger anti-proliferative action on Bel7402 and SMMC-7721 cells under hypoxia than that in normoxia. Both matrine and miR-199a-5p exhibited significant inhibitory effects on migration, invasion and EMT in Bel7402 and SMMC-7721 cells under hypoxia. Further study showed that miR-199a-5p was downregulated in HCC cell lines, and this microRNA was identified to directly target HIF-1α, resulting in decreased HIF-1α expression. Matrine induced miR-199a-5p expression, decreased HIF-1α expression and inhibited metastasis of Bel7402 and SMMC-7721 cells, while miR-199a-5p knockdown reversed the inhibitory effects of matrine on cell migration, invasion, EMT and HIF-1α expression. In vivo, matrine showed significant anti-metastatic activity in the nude mouse xenograft model. H&E and IHC analysis indicated that lung and liver metastasis nodules were reduced, and the protein expression of HIF-1α and Vimentin were significantly decreased by i.p injection of matrine.ConclusionsMatrine exhibits significant anti-metastatic effect on HCC, which is attributed to enhanced miR-199a-5p expression and subsequently impaired HIF-1α signaling and EMT. These findings suggest that miR-199a-5p is a potential therapeutic target of HCC, and matrine may represent a promising anti-metastatic medication for HCC therapy.     

MicroRNA-21 accelerates hepatocyte proliferation in vitro via PI3K/Akt signaling by targeting PTEN

MicroRNAs (miRNAs) are involved in controlling hepatocyte proliferation during liver regeneration. In this study, we established the miRNAs-expression patterns of primary hepatocytes in vitro under stimulation of epidermal growth factor (EGF), and found that microRNA-21 (miR-21) was appreciably up-regulated and peaked at 12 h. In addition, we further presented evidences indicating that miR-21 promotes primary hepatocyte proliferation through in vitro transfecting with miR-21 mimics or inhibitor. We further demonstrated that phosphatidylinositol 3′-OH kinase (PI3K)/Akt signaling was altered accordingly, it is, by targeting phosphatase and tensin homologue deleted on chromosome 10, PI3K/Akt signaling is activated by miR-21 to accelerate hepatocyte rapid S-phase entry and proliferation in vitro.     

Radiosensitizer EXO-miR-197-3p Inhibits Nasopharyngeal Carcinoma Progression and Radioresistance by Regulating the AKT/mTOR Axis and HSPA5-mediated Autophagy

The biological functions of exosomes and microRNAs (miRs) in nasopharyngeal carcinoma (NPC) remain largely unexplored. Here, miR-197-3p was screened and identified, and whose level was reduced in serum and exosomes of patients with NPC. MiR-197-3p might be a good diagnostic and prognostic indicator. Our data showed that miR-197-3p expression was closely related to radioresistance, apoptosis, proliferation, migration, and survival of NPC. Inhibition of miR-197-3p expression in vitro could promote the proliferation and migration of NPC cells, while promotion of miR-197-3p expression in vivo could significantly inhibit the growth and enhance the radiosensitivity of NPC cells. From the perspective of mechanism, miR-197-3p could inhibit AKT/mTOR phosphorylation activation, inhibit an activated pathway of AKT/mTOR, target Heat Shock 70-kDa Protein 5(HSPA5) related to endoplasmic reticulum homeostasis, inhibit HSPA5-mediated autophagy, and reverse the radioresistance of NPC. Interestingly, exosomal miR-197-3p (EXO-miR-197-3p) reduced the proliferation and migration potential of NPC cells in vitro, and tumor growth and radioresistance of NPC cells in vivo. EXO-miR-197-3p inhibited NPC progression and radioresistance by regulating AKT/mTOR phosphorylation activation and HSPA5-mediated autophagy. In conclusion, our results highlight the potential of EXO-miR-197-3p as an effective radiosensitizer and therapeutic agent for refractory NPC.     

Circulating Exosomal miR-17-5p and miR-92a-3p Predict Pathologic Stage and Grade of Colorectal Cancer

Exosomes are extracellular membrane vesicles of 50- to 130-nm diameter secreted by most tumor cells. Exosomes can mediate the intercellular transfer of proteins and RNAs, including microRNAs (miRNAs), and promote both tumorigenesis and premetastatic niche formation. In this study, we performed exosomal RNA sequencing to identify candidate exosomal miRNAs that could be associated with colorectal cancer (CRC) and its distant metastasis. The expression profiles of exosomal miRNA, as secreted by isogenic human primary CRC cell line SW480 and highly metastatic cell line SW620, were analyzed and the potential targets related to tumorigenesis and metastatic progression were investigated. We found that 25 miRNAs had been up-regulated and 5 miRNAs had been down-regulated in exosomes purified from SW620 culture supernatant. Candidate miRNAs were further evaluated for CRC diagnosis using quantitative real-time polymerase chain reaction in CRC patients. Higher expression levels of circulating exosomal miR-17-5p and miR-92a-3p were significantly associated with pathologic stages and grades of the CRC patients. CONCLUSIONS: Circulating exosomal miR-17-5p and miR-92a-3p may provide a promising noninvasive prognostic biomarker for primary and metastatic CRC.     

Overexpression of microRNA-23a-5p induces myocardial infarction by promoting cardiomyocyte apoptosis through inhibited of PI3K/AKT signalling pathway

Myocardial infarction (MI) leads to cardiac remodelling and heart failure. Cardiomyocyte apoptosis is considered a critical pathological phenomenon accompanying MI, but the pathogenesis mechanism remains to be explored. MicroRNAs (miRs), with the identity of negative regulator of gene expression, exist as an important contributor to apoptosis. During the experiment of this study, MI mice models were successfully established and sequencing data showed that the expression of miR-23a-5p was significantly enhanced during MI progression. Further steps were taken and it showed that apoptosis of cardiac cells weakened as miR-23a-5p was downregulated and on the contrary that apoptosis strengthened with the overexpression of miR-23a-5p. To explore its working mechanisms, bioinformatics analysis was conducted by referring to multi-databases to predict the targets of miR-23a-5p. Further analysis suggested that those downstream genes enriched in several pathways, especially in the PI3K/Akt singling pathway. Furthermore, it demonstrated that miR-23a-5p was negatively related to the phosphorylation of PI3K/Akt, which plays a critical role in triggering cell apoptosis during MI. Recilisib-activated PI3K/Akt singling pathway could restrain apoptosis from inducing miR-23a-5p overexpression, and Miltefosine-blocked PI3K/Akt singling pathway could restrict apoptosis from inhibiting miR-23a-5p reduction. In conclusion, these findings revealed the pivotal role of miR-23a-5p-PI3K/Akt axis in regulating apoptosis during MI, introducing this novel axis as a potential indicator to detect ischemic heart disease and it could be used for therapeutic intervention.     

CircRAPGEF5 Promotes the Proliferation and Metastasis of Lung Adenocarcinoma through the miR-1236-3p/ZEB1 Axis and Serves as a Potential Biomarker

Lung adenocarcinoma (LAD) is a common malignancy; however, its underlying molecular mechanism is unclear. Circular RNAs (circRNAs) serve as significant cancer regulators. The overexpression of circRAPGEF5 in LAD tissues and cells indicated that it may be involved in promoting LAD progression. Analysis of 61 LAD tissues revealed that circRAPGEF5 was related to lymph node metastasis. Functionally, circRAPGEF5 promoted the proliferation, migration, invasion, and epithelial-mesenchymal transition of LAD cells in vitro and promoted LAD cells growth in vivo. Mechanistically, dual-luciferase reporter assays confirmed direct interaction of circRAPGEF5, miR-1236-3p, and ZEB1. miR-1236-3p was upregulated and ZEB1 expression reduced after circRAPGEF5 knockdown, and the proliferation, migration, and invasion of LAD cells was inhibited. circRAPGEF5 was significantly overexpressed in LAD cell exosomes, and co-culture experiments showed that exosomal circRAPGEF5 enhanced the metastatic ability of LAD cells. Further experiments found that serum exosomal circRAPGEF5 was overexpressed in LAD; moreover, the area under the receiver operator characteristic curve of exosomal circRAPGEF5 was superior to that of serum carcinoembryonic antigen (CEA). Jointly detected serum exosomal circRAPGEF5 and serum CEA had better diagnostic performance than when detected individually. Thus, exosomal circRAPGEF5 could promote the proliferation and metastasis of LAD via the miR-1236-3p/ZEB1 axis and serum exosomal circRAPGEF5 may serve as a promising biomarker for LAD.     

MiR-122 Inhibits Cell Proliferation and Tumorigenesis of Breast Cancer by Targeting IGF1R

miRNAs are emerging as critical regulators in carcinogenesis and tumor progression. Recently, microRNA-122 (miR-122) has been proved to play an important role in hepatocellular carcinoma, but its functions in the context of breast cancer (BC) remain unknown. In this study, we report that miR-122 is commonly downregulated in BC specimens and BC cell lines with important functional consequences. Overexpression of miR-122 not only dramatically suppressed cell proliferation, colony formation by inducing G1-phase cell-cycle arrest in vitro, but also reduced tumorigenicity in vivo. We then screened and identified a novel miR-122 target, insulin-like growth factor 1 receptor (IGF1R), and it was further confirmed by luciferase assay. Overexpression of miR-122 would specifically and markedly reduce its expression. Similar to the restoring miR-122 expression, IGF1R downregulation suppressed cell growth and cell-cycle progression, whereas IGF1R overexpression rescued the suppressive effect of miR-122. To identify the mechanisms, we investigated the Akt/mTOR/p70S6K pathway and found that the expression of Akt, mTOR and p70S6K were suppressed, whereas re-expression of IGF1R which did not contain the 3′UTR totally reversed the inhibition of Akt/mTOR/p70S6K signal pathway profile. We also identified a novel, putative miR-122 target gene, PI3CG, a member of PI3K family, which further suggests miR-122 may be a key regulator of the PI3K/Akt pathway. In clinical specimens, IGF1R was widely overexpressed and its mRNA levels were inversely correlated with miR-122 expression. Taken together, our results demonstrate that miR-122 functions as a tumor suppressor and plays an important role in inhibiting the tumorigenesis through targeting IGF1R and regulating PI3K/Akt/mTOR/p70S6K pathway. Given these, miR-122 may serve as a novel therapeutic or diagnostic/prognostic-target for treating BC.     

MiR-23a-3p promoted G1/S cell cycle transition by targeting protocadherin17 in hepatocellular carcinoma

MiR-23a-3p has been shown to promote liver cancer cell growth and metastasis and regulate that of chemosensitivity. Protocadherin17 (PCDH17) is a tumor suppressor gene and plays an essential part in cell cycle of hepatocellular carcinoma (HCC). This study aimed at evaluating the effects of miR-23a-3p and PCDH17 on HCC cell cycle and underlining the mechanism. The level of miR-23a-3p was up-regulated, while PCDH17 level was down-regulated in HCC tissues compared to adjacent tissues. For the in vitro studies, high expression of miR-23a-3p down-regulated PCDH17 level; increased cell viability; promoted G1/S cell cycle transition; up-regulated cyclin D1, cyclin E, CDK2, CDK4, p-p27, and p-RB levels; and down-regulated the expression of p27. Dual luciferase reporter assay suggested PCDH17 was a target gene of miR-23a-3p. MiR-23a-3p inhibitor and PCDH17 siRNA led to an increase in cell viability and the number of cells in the S phase and up-regulated cyclin D1 and cyclin E levels, compared with miR-23a-3p inhibitor and NC siRNA group. For the in vivo experiments, high expression of miR-23a-3p promoted tumor growth and reduced PCDH17 level in the cytoplasm. These results indicated that high expression of miR-23a-3p might promote G1/S cell cycle transition by targeting PCDH17 in HCC cells. The miR-23a-3p could be considered as a molecular target for HCC detection.