MicroRNA-203 leads to G1 phase cell cycle arrest in laryngeal carcinoma cells by directly targeting survivin

Previous studies have shown that miR-203 acts as a tumor-suppressive microRNA in various cancers, but its roles in laryngeal carcinoma are still contradicted. Here, we found that miR-203 inhibited the growth of laryngeal cancer cells and survivin was a direct target of miR-203. Moreover, silencing of survivin recapitulated the effect of miR-203 on cell cycle progression, whereas overexpression of survivin reversed this effect. Additionally, qRT-PCR showed the reciprocal relationship between miR-203 and survivin in laryngeal cancer tissues. These findings indicate that miR-203 inhibits the proliferation of laryngeal carcinoma cells by directly targeting survivin, suggesting its application in anti-cancer therapeutics.     

Zyxin Is a Transforming Growth Factor-β (TGF-β)/Smad3 Target Gene That Regulates Lung Cancer Cell Motility via Integrin α5β1

Although TGF-β acts as a tumor suppressor in normal tissues and in early carcinogenesis, these tumor suppressor effects are lost in advanced malignancies. Single cell migration and epithelial-mesenchymal transition (EMT), both of which are regulated by TGF-β, are critical steps in mediating cancer progression. Here, we sought to identify novel direct targets of TGF-β signaling in lung cancer cells and have indentified the zyxin gene as a target of Smad3-mediated TGF-β1 signaling. Zyxin concentrates at focal adhesions and along the actin cytoskeleton; as such, we hypothesized that cytoskeletal organization, motility, and EMT in response to TGF-β1 might be regulated by zyxin expression. We show that TGF-β1 treatment of lung cancer cells caused rapid phospho-Smad3-dependent expression of zyxin. Zyxin expression was critical for the formation and integrity of cell adherens junctions. Silencing of zyxin decreased expression of the focal adhesion protein vasodilator-activated phospho-protein (VASP), although the formation and morphology of focal adhesions remained unchanged. Zyxin-depleted cells displayed significantly increased integrin α5β1 levels, accompanied by enhanced adhesion to fibronectin and acquisition of a mesenchymal phenotype in response to TGF-β1. Zyxin silencing led to elevated integrin α5β1-dependent single cell motility. Importantly, these features are mirrored in the K-ras-driven mouse model of lung cancer. Here, lung tumors revealed decreased levels of both zyxin and phospho-Smad3 when compared with normal tissues. Our data thus demonstrate that zyxin is a novel functional target and effector of TGF-β signaling in lung cancer. By regulating cell-cell junctions, integrin α5β1 expression, and cell-extracellular matrix adhesion, zyxin may regulate cancer cell motility and EMT during lung cancer development and progression.     

Long non-coding RNA LINC00488 facilitates thyroid cancer cell progression through miR-376a-3p/PON2

Objective: Long non-coding RNAs (lncRNAs) recently have been identified as influential indicators in a variety of malignancies. The aim of the present study was to identify a functional lncRNA LINC00488 and its effects on thyroid cancer in the view of cell proliferation and apoptosis.Methods: In order to evaluate the effects of LINC00488 on the cellular process of thyroid cancer, we performed a series of in vitro experiments, including cell counting kit-8 (CCK-8) assay, EdU (5-ethynyl-2′-deoxyuridine) assay, flow cytometry, transwell chamber assay, Western blot and RT-qPCR. The target gene of LINC00488 was then identified by bioinformatics analysis (DIANA and TargetScan). Finally, a series of rescue experiments was conducted to validate the effect of LINC00488 and its target genes on proliferation, migration, invasion and apoptosis of thyroid cancer.Results: Our findings revealed that LINC00488 was highly expressed in thyroid cancer cell lines (BCPAP, BHP5-16, TPC-1 and CGTH-W3) and promoted the proliferation, migration and invasion, while inhibited the apoptosis of thyroid cancer cells (BCPAP and TPC-1). The results of bioinformatics analysis and dual luciferase reporter gene assay showed that LINC00488 could directly bind to miR-376a-3p and down-regulated the expression level of miR-376a-3p. In addition, Paraoxonase-2 (PON2) was a target gene of miR-376a-3p and negatively regulated by miR-376a-3p. Rescue experiment indicated that LINC00488 might enhance PON2 expression by sponging miR-376a-3p in thyroid cancer.Conclusion: Taken together, our study revealed that lncRNA LINC00488 acted as an oncogenic gene in the progression of thyroid cancer via regulating miR-376a-3p/PON2 axis, which indicated that LINC00488-miR-376a-3p-PON2 axis could serve as novel biomarkers or potential targets for the treatment of thyroid cancer.     

Cyclin-dependent kinase 4 is a novel target in micoRNA-195-mediated cell cycle arrest in bladder cancer cells

miRNAs are a class of small-noncoding RNAs capable of negatively regulating gene expression. Here, we found that miR-195 is down-regulated in human bladder cancer tissue versus normal adjacent tissue. To better characterize the role of miR-195 in bladder cancer, we conducted gain of function analysis by transfecting bladder cancer cell line T24 with chemically synthesized miR-195 mimic. We identified CDK4, an early G1 cell cycle regulator, as a novel target of miR-195. Selective over-expression of miR-195 could induce G1-phase arrest in T24 cells, and subsequently inhibit T24 cell growth. These findings indicate that miR-195 could be a potential tumor suppressor in bladder cancer.     

DGCR5 promotes cancer stem cell-like properties of radioresistant laryngeal carcinoma cells by sponging miR-506 via Wnt pathway

Cancer stem cells (CSCs) have been recognized as the significant cause of tumor recurrence. Long noncoding RNAs (lncRNAs) are involved in various cancers, including human laryngeal cancer. So far the correlation between lncRNA DiGeorge syndrome critical region gene 5 (DGCR5) and CSC-like properties in human laryngeal cancer remains barely known. In our current study, two human larynx squamous carcinoma cell lines (Hep-2 and Hep-2R) with different radio sensitivities were cultured. Interestingly, CSC-like phenotypes were much more enriched in Hep-2R cells. We found that DGCR5 was upregulated and microRNA-506 (miR-506) was downregulated in Hep-2R cells. In addition, silence of DGCR5 could inhibit the stemness and enhance the radiosensitivity of Hep-2R cells. Meanwhile, overexpression of miR-506 also suppressed the CSC-like traits and the radiosensitivity was increased significantly. In addition, miR-506 was predicted as target of DGCR5 and the correlation between them was validated in our study. Finally, we observed that Wnt pathway exerted a significant role in human laryngeal CSCs and DGCR5 inhibition could repress Wnt signaling activity by sponging miR-506. In vivo assays were performed and we found that DCGR5 depressed stemness of human laryngeal cancer cells through modulating miR-506 and Wnt signaling pathway. Taken these together, we reported that DGCR5 induced CSC-like properties by sponging miR-506 through activating Wnt in human laryngeal carcinoma cells.     

Tumor-suppressive microRNA-10a inhibits cell proliferation and metastasis by targeting Tiam1 in esophageal squamous cell carcinoma

Aberrant microRNAs (miRNAs) expressions could contribute to the progression of numerous cancers, including esophageal squamous cell carcinoma, while miR-10a participates in multiple biological processes on cancers. However, the molecular mechanism of miR-10a in esophageal squamous cell carcinoma (ESCC) has not been investigated. Herein, miR-10a was significantly reduced in ESCC clinical tissues and ESCC cell lines (EC109 and TE-3). In addition, immunohistochemistry indicated that the expressions of α-SMA, Ki-67, and PCNA in tumor tissues were higher than that of controls. In vitro, overexpression of miR-10a dramatically suppressed cell proliferation and enhanced cell apoptosis, while the decrease of miR-10a expressed the opposite outcome. Specially, overexpression of miR-10a caused a G0/G1 peak accumulation. Moreover, miR-10a also negatively regulated ESCC cell migration and invasion. Furthermore, targetscan bioinformatics predictions and the dual-luciferase assay confirmed that Tiam1 was a direct target gene of miR-10a. The statistical analysis showed Tiam1 was negatively in correlation with miR-10a in ESCC patient samples. And silencing Tiam1 could lead to a decline on cell growth, invasion, and migration in ESCC cell lines, while it could enhance cell apoptosis and cause a G0/G1 peak accumulation. In vivo, it revealed that miR-10a notably decreased the tumor growth and metastasis in xenograft model and pulmonary metastasis model. And it showed a lower expressions of Tiam1 in the miR-10a mimics group by immunohistochemistry. Taken together the results, they indicated that miR-10a might function as a novel tumor suppressor in vitro and in vivo via targeting Tiam1, suggesting miR-10a to be a candidate biomarker for the ESCC therapy.     

Inhibition of RAC1-GEF DOCK3 by miR-512-3p contributes to suppression of metastasis in non-small cell lung cancer

MicroRNAs are a class of small non-coding RNAs regulating gene expression. In this study, we demonstrated that retinoic acid (RA) treatment increases the expression of miR-512-3p. Overexpression of miR-512-3p inhibited cell adhesion, migration, and invasion in non-small cell lung cancer (NSCLC) cell lines A549 and H1299. miR-512-3p inhibitor partially reversed these effects in H1299 cells stably expressing miR-512. We identified DOCK3, a RAC1-GEF (guanine nucleotide exchange factor), as a target gene of miR-512-3p. Overexpression of miR-512-3p led to the decrease of DOCK3 protein but not its mRNA. Knockdown of DOCK3 resulted in similar effects on adhesion, migration, and invasion as observed of miR-512-3p overexpression. Active RAC1 pull-down assay indicated that overexpression of miR-512-3p could decrease the activity of RAC1 with a higher efficiency than that of DOCK3 knockdown. Furthermore, expression of miR-512-3p was suppressed in most NSCLC patient tumor samples compared to its paired normal controls, suggesting that miR-512-3p might play a crucial role in lung cancer development. In conclusion, our results supported that miR-512-3p could inhibit tumor cell adhesion, migration, and invasion by regulating the RAC1 activity via DOCK3 in NSCLC A549 and H1299 cell lines.     

lncRNA PCAT19 promotes the proliferation of laryngocarcinoma cells via modulation of the miR-182/PDK4 axis

The mechanism of tumorigenesis has not been fully identified in laryngeal cancer, which accounts for one fourth of patents with head and neck tumors. Long noncoding RNA PCAT19 has been shown to participate in the prostate cancer progression. However, little is known about the role of PCAT19 in the tumorigenesis of laryngeal cancer. In our study, it was shown that the expression levels of PCAT19 was increased in laryngeal tumor tissues and associated with decreased overall survival. Using laryngeal cancer cells lines HEp-2 and AMC-HN-8, it was demonstrated that knockdown of PCAT19 decreased the cell proliferation, increased the mitochondrial respiration, and inhibited the glycolysis. In detail, it showed that the PDK4 expression and PDHE1α phosphorylation levels were decreased upon the PCAT19 knockdown. Further studies indicated that miR-182 functioned as the bridge between PCAT19 and PDK4, which could also regulate the cellular metabolism thus affecting the cell proliferation. Furthermore, it was shown that the PCAT19/miR-182/PDK4 axis existed and regulated cell proliferation by modulating glycolysis and mitochondrial respiration. Finally, we showed that the PCAT19 knockdown decreased the tumor growth in vivo, possibly through regulating the miR-182/PDK4 axis. In conclusion, we demonstrated that lncRNA PCAT19 promoted cell proliferation and tumorigenesis by modulating the miR-182/PDK4 axis and the metabolism balance. PCAT19 might become a promising new target for laryngeal cancer therapeutics.     

Upregulation of microRNA-141 suppresses epithelial-mesenchymal transition and lymph node metastasis in laryngeal cancer through HOXC6-dependent TGF-β signaling pathway

Laryngeal cancer is one of the most malignant cancers among the head and neck malignant tumors. Abnormal expression of microRNAs (miRNAs) contributes to cancer development through regulating proliferation and apoptosis of cancer cells. In this study, we aim to explore the roles of microRNA-141 (miR-141), Homeobox C6 (HOXC6) and TGF-β signaling pathway in epithelial-mesenchymal transition (EMT) and lymph node metastasis in laryngeal cancer. Initially, we identified differentially expressed genes in laryngeal cancer, among which HOXC6 was identified. Then the target miRNA of HOXC6 was predicted and verified. Next, expression of miR-141, HOXC6, TGF-β1, Smad3, Vimentin and Snail in cancer tissues was detected. Then, AMC-HN-8 cells were transfected with miR-141 mimic, miR-141 inhibitor and HOXC6-siRNA to investigate specific role of miR-141, HOXC6 and TGF-β signaling pathway in laryngeal cancer in vivo and in vitro. Our results showed that HOXC6 was a target gene of miR-141, which was downregulated in laryngeal cancer. Besides, overexpression of miR-141 could downregulate HOXC6 and inhibit the TGF-β signaling pathway. Upregulation of miR-141 or silencing of HOXC6 can repress EMT, viability, migration and invasion abilities of laryngeal cancer cells. In addition, upregulation of miR-141 inhibited the tumor growth and lymph node metastasis in vivo. In summary, our findings demonstrated that upregulated miR-141 decreased HOXC6 expression, and inhibited the TGF-β signaling pathway, EMT and lymph node metastasis in laryngeal cancer, which is of clinical significance in the treatment of laryngeal cancer.     

Synemin interacts with the LIM domain protein zyxin and is essential for cell adhesion and migration

Synemin is a unique cytoplasmic intermediate filament protein for which there is limited understanding of its exact cellular functions. The single human synemin gene encodes at least two splice variants named α-synemin and β-synemin, with the larger α-synemin containing an additional 312 amino acid insert within the C-terminal tail domain. We report herein that, by using the entire tail domain of the smaller β-synemin as the bait in a yeast two-hybrid screen of a human skeletal muscle cDNA library, the LIM domain protein zyxin was identified as an interaction partner for human synemin. The synemin binding site in human zyxin was subsequently mapped to the C-terminal three tandem LIM-domain repeats, whereas the binding site for zyxin within β-synemin is within the C-terminal 332 amino acid region (SNβTII) at the end of the long tail domain. Transient expression of SNβTII within mammalian cells markedly reduced zyxin protein level, blocked localization of zyxin at focal adhesion sites and resulted in decreased cell adhesion and increased motility. Knockdown of synemin expression with siRNAs within mammalian cells resulted in significantly compromised cell adhesion and cell motility. Our results suggest that synemin participates in focal adhesion dynamics and is essential for cell adhesion and migration.     

Downregulation of miR-16 promotes growth and motility by targeting HDGF in non-small cell lung cancer cells

MicroRNAs play important roles in the development and progression of non-small cell lung cancer (NSCLC). miR-16 functions as a tumor-suppressor and is inhibited in several malignancies. Herein, we validated that miR-16 is downregulated in NSCLC tissue samples and cell lines. Ectopic expression of miR-16 significantly inhibited cell proliferation and colony formation. Moreover, miR-16 suppressed cell migration and invasion in NSCLC cells. Hepatoma-derived growth factor (HDGF) was found to be a direct target of miR-16 in NSCLC cell lines. Rescue experiments showed that the suppressive effect of miR-16 on cell proliferation, colony formation, migration, and invasion is partially mediated by inhibiting HDGF expression. This study indicates that miR-16 might be associated with NSCLC progression, and suggests an essential role for miR-16 in NSCLC.     

miR-219-5p targets TBXT and inhibits breast cancer cell EMT and cell migration and invasion

miR-219-5p has been reported to act as either a tumor suppressor or a tumor promoter in different cancers by targeting different genes. In the present study, we demonstrated that miR-219-5p negatively regulated the expression of TBXT, a known epithelial–mesenchymal transition (EMT) inducer, by directly binding to TBXT 3′-untranslated region. As a result of its inhibition on TBXT expression, miR-219-5p suppressed EMT and cell migration and invasion in breast cancer cells. The re-introduction of TBXT in miR-219-5p overexpressing cells decreased the inhibitory effects of miR-219 on EMT and cell migration and invasion. Moreover, miR-219-5p decreased breast cancer stem cell (CSC) marker genes expression and reduced the mammosphere forming capability of cells. Overall, our study highlighted that TBXT is a novel target of miR-219-5p. By suppressing TBXT, miR-219-5p plays an important role in EMT and cell migration and invasion of breast cancer cells.     

MiR-15a-16 represses Cripto and inhibits NSCLC cell progression

MicroRNAs (miRNAs) are small noncoding RNAs that have important roles in cancer. The altered expressions of miRNAs and their target genes are frequently detected in various tumors. In this study, downregulation of miR-15a-16 in nonsmall cell lung cancer (NSCLC) was found to be inversely correlated with Cripto. Results from the Luciferase reporter assay and Western blot analysis also confirmed that Cripto is a direct target of miR-15a-16. In addition, transfection of miR-15a-16 expression plasmid inhibited the invasion ability and promoted the apoptosis of NCI-H23 and NCI-H358 cells. Moreover, miR-15a-16 overexpression suppressed tumor growth in vivo. These findings clearly suggest that the downregulation of miR-15a-16 with Cripto amplification may be involved in the development of NSCLC.     

miRNA-29c Suppresses Lung Cancer Cell Adhesion to Extracellular Matrix and Metastasis by Targeting Integrin β1 and Matrix Metalloproteinase2 (MMP2)

Our pilot study using miRNA arrays found that miRNA-29c (miR-29c) is differentially expressed in the paired low-metastatic lung cancer cell line 95C compared to the high-metastatic lung cancer cell line 95D. Bioinformatics analysis shows that integrin β1 and matrix metalloproteinase 2 (MMP2) could be important target genes of miR-29c. Therefore, we hypothesized that miR-29c suppresses lung cancer cell adhesion to extracellular matrix (ECM) and metastasis by targeting integrin β1 and MMP2. The gain-of-function studies that raised miR-29c expression in 95D cells by using its mimics showed reductions in cell proliferation, adhesion to ECM, invasion and migration. In contrasts, loss-of-function studies that reduced miR-29c by using its inhibitor in 95C cells promoted proliferation, adhesion to ECM, invasion and migration. Furthermore, the dual-luciferase reporter assay demonstrated that miR-29c inhibited the expression of the luciferase gene containing the 3′-UTRs of integrin β1 and MMP2 mRNA. Western blotting indicated that miR-29c downregulated the expression of integrin β1 and MMP2 at the protein level. Gelatin zymography analysis further confirmed that miR-29c decreased MMP2 enzyme activity. Nude mice with xenograft models of lung cancer cells confirmed that miR-29c inhibited lung cancer metastasis in vivo, including bone and liver metastasis. Taken together, our results demonstrate that miR-29c serves as a tumor metastasis suppressor, which suppresses lung cancer cell adhesion to ECM and metastasis by directly inhibiting integrin β1 and MMP2 expression and by further reducing MMP2 enzyme activity. The results show that miR-29c may be a novel therapeutic candidate target to slow lung cancer metastasis.     

miR-210 is induced by hypoxia and regulates neural cell adhesion molecule in prostate cells

Hypoxia in prostate tumours has been associated with disease progression and metastasis. MicroRNAs are short noncoding RNA molecules that are important in several cell processes, but their role in hypoxic signalling is still poorly understood. miR-210 has been linked with hypoxic mechanisms, but this relationship has been poorly characterised in prostate cancer. In this report, the link between hypoxia and miR-210 in prostate cancer cells is investigated. Polymerase chain reaction analysis demonstrates that miR-210 is induced by hypoxia in prostate cancer cells using in vitro cell models and an in vivo prostate tumour xenograft model. Analysis of The Cancer Genome Atlas prostate biopsy datasets shows that miR-210 is significantly correlated with Gleason grade and other clinical markers of prostate cancer progression. Neural cell adhesion molecule (NCAM) is identified as a target of miR-210, providing a biological mechanism whereby hypoxia-induced miR-210 expression can contribute to prostate cancer. This study provides evidence that miR-210 is an important regulator of cell response to hypoxic stress and proposes that its regulation of NCAM may play an important role in the pathogenesis of prostate cancer.     

Knockdown of DGCR5 enhances the radiosensitivity of human laryngeal carcinoma cells via inducing miR-195

Long noncoding RNAs (lncRNAs) exert critical roles in the development of various cancers, including human laryngeal cancer. Radioresistance contributes to the predominant causes of laryngeal cancer recurrence after radiotherapy. The aim of our study was to investigate the association of dysregulated lncRNA and radiation resistance in human larynx squamous carcinoma. Here, we investigated the biological roles of lncRNA DiGeorge syndrome critical region gene 5 (DGCR5) in radioresistance of human laryngeal cancer. Two human larynx squamous carcinoma cell lines (Hep-2 and Hep-2R), with different radiosensitivities in vitro were used in the present study. We observed that DGCR5 was significantly upregulated in Hep-2R cells. Inhibition of DGCR5 by LV-shDGCR5 transfection restrained Hep-2R cell proliferation and sensitized cells to radiation. Reversely, overexpression of DGCR5 exhibited an opposite phenomenon in vitro. In addition, microRNA (miR)-195 was predicted as a direct downstream target of DGCR5. Dual-luciferase reporter and RNA immunoprecipitation assays verified the direct interaction between them. Meanwhile, miR-195 was observed to be reduced in Hep-2R cells and miR-195 mimics repressed Hep-2 cell growth. Moreover, radiosensitivity of Hep-2R cells was greatly enhanced by overexpression of miR-195, which could be reversed by upregulation of DGCR5. Finally, in vivo experiments were used to validate that knockdown of DGCR5 suppressed laryngeal carcinoma via targeting miR-195. In conclusion, we indicated that DGCR5 could contribute to the radioresistance of human laryngeal carcinoma cells via sponging miR-195.     

MicroRNA-140 inhibit prostate cancer cell invasion and migration by targeting YES proto-oncogene 1

Prostate cancer (PCa), which is an aggressive malignancy of the male genitourinary system. In the present study, the effects of microRNA-140 (miR-140) on PCa were determined. We transfected miR-140 mimics or negative control into PCa cells, and we used MTT, wound healing, and Transwell assays for determining the capacities of miR-140 in cell proliferation, migration, and invasion, respectively. We also confirmed the relationship between miR-140 and YES proto-oncogene 1 (YES1) using Luciferase reporter assay. The results showed that miR-140 was downregulated in PCa cells and tissues, and overexpression of miR-140 could significantly suppress their capacities of proliferation, migration, and invasion. Moreover, YES1 was shown to be a direct target of miR-140. Moreover, miR-140 expression is negatively correlated with YES1 levels. miR-140 exhibits significant tumor-suppressive effects in PCa by inhibiting YES1. The study indicated that miR-140 and YES1 could be the potential targets for PCa therapy.