PAX6, a novel target of miR-335, inhibits cell proliferation and invasion in glioma cells

Inhalational Anesthetics Inhibit Neuroglioma Cell Proliferation and Migration via miR-138, -210 and -335

Inhalational anesthetics was previously reported to suppress glioma cell malignancy but underlying mechanisms remain unclear. The present study aims to investigate the effects of sevoflurane and desflurane on glioma cell malignancy changes via microRNA (miRNA) modulation. The cultured H4 cells were exposed to 3.6% sevoflurane or 10.3% desflurane for 2 h. The miR-138, -210 and -335 expression were determined with qRT-PCR. Cell proliferation and migration were assessed with wound healing assay, Ki67 staining and cell count kit 8 (CCK8) assay with/without miR-138/-210/-335 inhibitor transfections. The miRNA downstream proteins, hypoxia inducible factor-1α (HIF-1α) and matrix metalloproteinase 9 (MMP9), were also determined with immunofluorescent staining. Sevoflurane and desflurane exposure to glioma cells inhibited their proliferation and migration. Sevoflurane exposure increased miR-210 expression whereas desflurane exposure upregulated both miR-138 and miR-335 expressions. The administration of inhibitor of miR-138, -210 or -335 inhibited the suppressing effects of sevoflurane or desflurane on cell proliferation and migration, in line with the HIF-1α and MMP9 expression changes. These data indicated that inhalational anesthetics, sevoflurane and desflurane, inhibited glioma cell malignancy via miRNAs upregulation and their downstream effectors, HIF-1α and MMP9, downregulation. The implication of the current study warrants further study.

Sevoflurane and Desflurane Exposure Enhanced Cell Proliferation and Migration in Ovarian Cancer Cells via miR-210 and miR-138 Downregulation

Inhalational anaesthetics were previously reported to promote ovarian cancer malignancy, but underlying mechanisms remain unclear. The present study aims to investigate the role of sevoflurane- or desflurane-induced microRNA (miRNA) changes on ovarian cancer cell behaviour. The cultured SKOV3 cells were exposed to 3.6% sevoflurane or 10.3% desflurane for 2 h. Expression of miR-138, -210 and -335 was determined with qRT-PCR. Cell proliferation and migration were assessed with wound healing assay, Ki67 staining and Cell Counting Kit-8 (CCK8) assay with or without mimic miR-138/-210 transfections. The miRNA downstream effector, hypoxia inducible factor-1α (HIF-1α), was also analysed with immunofluorescent staining. Sevoflurane or desflurane exposure to cancer cells enhanced their proliferation and migration. miR-138 expression was suppressed by both sevoflurane and desflurane, while miR-210 expression was suppressed only by sevoflurane. miR-335 expression was not changed by either sevoflurane or desflurane exposure. The administration of mimic miR-138 or -210 reduced the promoting effects of sevoflurane and desflurane on cancer cell proliferation and migration, in line with the HIF-1α expression changes. These data indicated that inhalational agents sevoflurane and desflurane enhanced ovarian cancer cell malignancy via miRNA deactivation and HIF-1α. The translational value of this work needs further study.

MicroRNAs at the Crossroad of the Dichotomic Pathway Cell Death vs. Stemness in Neural Somatic and Cancer Stem Cells: Implications and Therapeutic Strategies

Stemness and apoptosis may highlight the dichotomy between regeneration and demise in the complex pathway proceeding from ontogenesis to the end of life. In the last few years, the concept has emerged that the same microRNAs (miRNAs) can be concurrently implicated in both apoptosis-related mechanisms and cell differentiation. Whether the differentiation process gives rise to the architecture of brain areas, any long-lasting perturbation of miRNA expression can be related to the occurrence of neurodevelopmental/neuropathological conditions. Moreover, as a consequence of neural stem cell (NSC) transformation to cancer stem cells (CSCs), the fine modulation of distinct miRNAs becomes necessary. This event implies controlling the expression of pro/anti-apoptotic target genes, which is crucial for the management of neural/neural crest-derived CSCs in brain tumors, neuroblastoma, and melanoma. From a translational point of view, the current progress on the emerging miRNA-based neuropathology therapeutic applications and antitumor strategies will be disclosed and their advantages and shortcomings discussed.

The Role of miRNA for the Treatment of MGMT Unmethylated Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the most common high-grade intracranial tumor in adults. It is characterized by uncontrolled proliferation, diffuse infiltration due to high invasive and migratory capacities, as well as intense resistance to chemo- and radiotherapy. With a five-year survival of less than 3% and an average survival rate of 12 months after diagnosis, GBM has become a focus of current research to urgently develop new therapeutic approaches in order to prolong survival of GBM patients. The methylation status of the promoter region of the O⁶-methylguanine–DNA methyltransferase (MGMT) is nowadays routinely analyzed since a methylated promoter region is beneficial for an effective response to temozolomide-based chemotherapy. Furthermore, several miRNAs were identified regulating MGMT expression, apart from promoter methylation, by degrading MGMT mRNA before protein translation. These miRNAs could be a promising innovative treatment approach to enhance Temozolomide (TMZ) sensitivity in MGMT unmethylated patients and to increase progression-free survival as well as long-term survival. In this review, the relevant miRNAs are systematically reviewed.

MicroRNA-758 acts as a tumor inhibitor in colorectal cancer through targeting PAX6 and regulating PI3K/AKT pathway

Recently, a number of microRNAs (miRNAs) have been reported to play different roles in human cancers, including colorectal cancer (CRC). However, the specific role of miR-758 has not been clarified in CRC. Therefore, the aim of the present study was to explore the role of miR-758 in CRC. RT-qPCR and western blot analysis were used to quantify the expression of miR-758 and genes. The function of miR-758 in CRC was investigated using Transwell, CCK-8 and luciferase reporter assays. According to the results, the downregulation of miR-758 expression was associated with aggressive behavior and poor prognosis in CRC patients. miR-758 was shown to restrain the cell viability and metastasis in CRC. In addition, it was confirmed that miR-758 directly targets PAX6 and inhibits CRC progression through targeting PAX6. The results also revealed that miR-758 blocked EMT and PI3K/AKT pathway in CRC. In conclusion, miR-758 acts as a tumor suppressor in CRC by downregulating PAX6.

PDIA4: The basic characteristics, functions and its potential connection with cancer

Disulfide bond formation is catalyzed by the protein disulfide Isomerases (PDI) family. This is a critical step in protein folding which occurs within the endoplasmic reticulum. PDIA4, as a member of the PDI family, can cause the adjustment of αIIβ 3 affinities which activate platelet and promote thrombosis formation. Endoplasmic reticulum response is triggered by accumulation of abnormal folding proteins concomitant with increasing PDIA4 expression. Besides, current researches indicate that activated platelets and ERS response affect tumor progression. And PDIA4, as previous reported, also participates in tumor progression by affecting cell apoptosis and DNA repair machinery without specific mechanisms revealed.Therefore, PDI inhibitor might possess great potential value in against tumor progression. In this review, we summarize information on PDIA4 including its the basic characteristics and its implication on tumor.

Epigenetic silencing of miR-335 induces migration by targeting insulin-like growth factor-1 receptor in multiple myeloma

Multiple myeloma (MM) is a common hematological malignancy and remains incurable. MiRNA-335 is a classic tumor suppressor, yet its expression pattern and biological role in MM is unclear. The aim of the present study was to determine the expression pattern, biological role, and mechanism of miR-335 in MM. In this study, we found that miR-335 expression was decreased in MM. The promoter of miR-335 was also hypermethylated in MM. It was found that over-expression of miR-335 or 5-azacytidine treatment suppressed migration of MM cells and down-regulated the expression of IGF-1R. MiR-335 thus acts as a metastatic suppressor by targeting IGF-1R in MM. Moreover, aberrant promoter hyper-methylation is critical for miR-335 silencing in MM. We also found that miR-335 assisted in predicting both the prognosis and progression of disease in MM patients. Observations might offer a new complementary diagnostic and therapeutic target in MM.

PAX6 Promoter Methylation Correlates with MDA-MB-231 Cell Migration, and Expression of MMP2 and MMP9

Objective: Breast cancer is a heterogeneous disease characterized by an accumulation of genetic and epigenetic alterations that lead tumor cells to acquire characteristics like the capacity for invasion and metastasis. Metastasis remains a major challenge in cancer management and understanding of its molecular basis should result in improved prevention, diagnosis, and treatment of breast cancer patients. The aim of this study was to investigate how promoter DNA methylation regulates PAX6 gene expression and influences breast carcinoma cell migration. Methods: PAX6 promoter methylation was detected by Methyl Specific-Multiplex Ligation Probe Amplification (MS-MLPA). Gene expression was evaluated using qRT-PCR, while the effect of PAX6 on migration was ssessed by wound healing assay. In addition, MMP2 and MMP9 genes were studied using different bioinformatic tools. Results: The PAX6 promoter is methylated in breast cancer cell lines and methylation in this region impacts on its expression. Migration assays revealed that PAX6 overexpression promotes cell migration, while PAX6 inhibition decreases it. More importantly, we found that migration is affected by PAX6 methylation status. Employing bioinformatic analysis, binding sites for PAX6 on the regulatory regions of the MMP2 and MMP9 genes were established, PAX6 overexpression increasing MMP2 and MMP9 expression at the mRNA level. Conclusion: Our study provides novel insights into epigenetic events that regulate PAX6 expression and molecular mechanisms by which PAX6 modifies the migration capacity of breast cancer cells.

Generation of a PAX6 knockout glioblastoma cell line with changes in cell cycle distribution and sensitivity to oxidative stress

BACKGROUND

The transcription factor PAX6 is expressed in various cancers. In anaplastic astrocytic glioma, PAX6 expression is inversely related to tumor grade, resulting in low PAX6 expression in Glioblastoma, the highest-grade astrocytic glioma. The aim of the present study was to develop a PAX6 knock out cell line as a tool for molecular studies of the roles PAX6 have in attenuating glioblastoma tumor progression.

METHODS

The CRISPR-Cas9 technique was used to knock out PAX6 in U251 N cells. Viral transduction of a doxycycline inducible EGFP-PAX6 expression vector was used to re-introduce (rescue) PAX6 expression in the PAX6 knock out cells. The knock out and rescued cells were rigorously characterized by analyzing morphology, proliferation, colony forming abilities and responses to oxidative stress and chemotherapeutic agents.

RESULTS

The knock out cells had increased proliferation and colony forming abilities compared to wild type cells, consistent with clinical observations indicating that PAX6 functions as a tumor-suppressor. Cell cycle distribution and sensitivity to H₂O₂ induced oxidative stress were further studied, as well as the effect of different chemotherapeutic agents. For the PAX6 knock out cells, the percentage of cells in G2/M phase increased compared to PAX6 control cells, indicating that PAX6 keeps U251 N cells in the G1 phase of the cell cycle. Interestingly, PAX6 knock out cells were more resilient to H₂O₂ induced oxidative stress than wild type cells. Chemotherapy treatment is known to generate oxidative stress, hence the effect of several chemotherapeutic agents were tested. We discovered interesting differences in the sensitivity to chemotherapeutic drugs (Temozolomide, Withaferin A and Sulforaphane) between the PAX6 expressing and non-expressing cells.

CONCLUSIONS

The U251 N PAX6 knock out cell lines generated can be used as a tool to study the molecular functions and mechanisms of PAX6 as a tumor suppressor with regard to tumor progression and treatment of glioblastoma.

MicroRNA-19 contributes to the malignant phenotypes of osteosarcoma in vitro by targeting Pax6

This study was conducted to detect the expression of miR-19 and Pax6 (Paired box protein 6) in human osteosarcoma cells and the effects on biological characteristics of osteosarcoma cells. Quantitative real-time polymerase chain reaction was used to detect the expression of Pax6 and miR-19 in normal human osteoblasts (hFOB 1.19) and osteosarcoma cell lines (U2OS, Saos-2, and MG-63). Results showed that miR-19 was significantly upregulated in osteosarcoma cell lines compared with that in hFOB 1.19 cells, while the expression of Pax6 messenger RNA was significantly downregulated. Pax6 was defined as the target gene of miR-19 which was validated by luciferase reporter gene analysis. Results indicated that miR-19 had an interaction with Pax6 3'-untranslated region. At the same time, the protein expression of Pax6 was significantly decreased in the MG-63 cells transfected with miR-19 mimic and was notably enhanced in osteosarcoma MG-63 cells transfected with miR-19 inhibitor. These data suggested that Pax6 was a target of miR-19 in osteosarcoma MG-63 cells. The effects of miR-19 on the biological behavior of MG-63 cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, flow cytometry, and Transwell assay. Results showed that the downregulation of miR-19 inhibited cell viability, reduced the percentage of cells in S phase and the number of cells passing through the Transwell chamber, and increased the number of apoptotic cells. Western blot analysis showed that the inhibition of miR-19 significantly increased the expression of epithelial proteins (E-cadherin and β-catenin) and decreased the expression of mesenchymal protein (Vimentin), extracellular signal-regulated kinase, and phosphorylated extracellular signal-regulated kinase in MG-63 cells. MiR-19 inhibitor and Pax6 small interfering RNA were simultaneously transfected into MG-63 cells. Results from 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, flow cytometry, and Transwell assay demonstrated that the inhibition of Pax6 expression in MG-63 cells could reverse the cell biological effects induced by the inhibition of miR-19 expression. Based on these findings, it was suggested that miR-19, upregulated in osteosarcoma cells, negatively regulated the expression of Pax6, which can promote the malignant phenotypes of osteosarcoma cells via activation of the extracellular signal-regulated kinase signaling pathways. Therefore, miR-19/Pax6 may offer potential for use as a target for the treatment of osteosarcoma.

[Construction of a lentiviral vector carrying short?hairpin RNA targeting PAX6 and its effect on proliferation of glioma U251 cells in vitro]

OBJECTIVE

To construct a lentiviral vector for delivering short hairpin RNA (shRNA) targeting PAX6 and investigate its effect on the proliferation of glioma U251 cells in vitro.

METHODS

Two small interfering RNA sequences targeting PAX6 gene were designed based on the reported sequence of PAX6 and annealed to form a double?stranded chain, which was inserted into a lentiviral vector to construct the recombinant lentiviral vector shRNA?PAX6. The recombinant vector was infected into U251 cells, and the expression of PAX6 mRNA and protein in the cells was detected by real?time PCR and Western blotting, respectively. The changes in the proliferation of U251 cells after the infection was assessed using MTT assay.

RESULTS

Double enzyme digestion of the lentiviral vector pLKD?CMV?G&NR?U6?shRNA yielded an 8208?bp fragment, and colony PCR and sequencing analysis confirmed successful construction of the lentiviral vector shRNA?PAX6. Infection of the cells with shRNA?PAX6 caused a significant reduction of the expressions of PAX6 mRNA and protein (P<0.05) and resulted in obviously increased proliferation of U251 cells (P<0.05).

CONCLUSION

We successfully constructed the recombinant vector shRNA?PAX6 for silencing PAX6 gene. PAX6 gene silencing results in increased proliferation of U251 cells in vitro.

MicroRNAs in glioblastoma pathogenesis and therapy: A comprehensive review

Glioblastoma (GBM), also known as grade IV astrocytoma, is the most aggressive primary intracranial tumor of the adult brain. MicroRNAs (miRNAs), a class of small non-coding RNA species, have critical functions across various biological processes. A great deal of progress has been made recently in dissecting miRNA pathways associated with the pathogenesis of GBM. miRNA expression signatures called gene signatures also characterize and contribute to the phenotypic diversity of GBM subclasses through their ability to regulate developmental growth and differentiation. miRNA molecules have been identified as diagnostic and prognostic biomarkers for patient stratification and may also serve as therapeutic targets and agents. This review summarizes: (i) the current understanding of the roles of miRNAs in the pathogenesis of GBM, (ii) the potential use of miRNAs in GBM diagnosis and glioma grading, (iii) further prospects of developing miRNAs as novel biomarkers and therapeutic targets for GBM, and (iv) important practical considerations when considering miRNA therapy for GBM patients.

MicroRNA-375 targets PAX6 and inhibits the viability, migration and invasion of human breast cancer MCF-7 cells

MicroRNAs (miRs) are a type of small non-coding RNA that serve crucial roles in the development and progression of breast cancer. However, the exact role and underlying molecular mechanism of miR-375 in mediating the growth and metastasis of breast cancer remains unknown. In the present study, reverse transcription-quantitative polymerase chain reaction and western blot analysis were conducted to examine RNA and protein expression. A luciferase reporter assay was performed to determine the association between miR-375 and paired box 6 (PAX6). The results of the current study indicate that the expression of miR-375 was reduced in breast cancer tissues compared with matched adjacent normal tissues. Transfection with miR-375 mimics led to a significant increase in levels of miR-375 in human breast cancer Michigan Cancer Foundation (MCF)-7 cells (P<0.05). The increase in miR-375 expression caused a significant decrease in the viability, migration and invasion of MCF-7 cells (P<0.05), accompanied by a reduced expression of matrix metalloproteinase (MMP) 2 and MMP9 proteins. Luciferase reporter assay identified PAX6 as a novel target of miR-375 and miR-375 in turn, negatively regulated the protein expression of PAX6 in MCF-7 cells. By contrast, overexpression of PAX6 led to a significant increase in MCF-7 cell viability (P<0.01) but did not affect the migration and invasion of MCF-7 cells, suggesting that the inhibitory effect of miR-375 on MCF-7 cell viability may be occurring, in part, via the direct targeting of PAX6.

Defective neuronal migration and inhibition of bipolar to multipolar transition of migrating neural cells by Mesoderm-Specific Transcript, Mest, in the developing mouse neocortex

Brain developmental disorders such as lissencephaly can result from faulty neuronal migration and differentiation during the formation of the mammalian neocortex. The cerebral cortex is a modular structure, where developmentally, newborn neurons are generated as a neuro-epithelial sheet and subsequently differentiate, migrate and organize into their final positions in the cerebral cortical plate via a process involving both tangential and radial migration. The specific role of Mest, an imprinted gene, in neuronal migration has not been previously studied. In this work, we reduced expression of Mest with in utero electroporation of neuronal progenitors in the developing embryonic mouse neocortex. Reduction of Mest levels by shRNA significantly reduced the number of neurons migrating to the cortical plate. Also, Mest-knockdown disrupted the transition of bipolar neurons into multipolar neurons migrating out of the sub-ventricular zone region. The migrating neurons also adopted a more tangential migration pattern upon knockdown of the Mest message, losing their potential to attach to radial glia cells, required for radial migration. The differentiation and migration properties of neurons via Wnt-Akt signaling were affected by Mest changes. In addition, miR-335, encoded in a Mest gene intron, was identified as being responsible for blocking the default tangential migration of the neurons. Our results suggest that Mest and its intron product, miR-335, play important roles in neuronal migration with Mest regulating the morphological transition of primary neurons required in the formation of the mammalian neocortex.

Implication of downregulation and prospective pathway signaling of microRNA-375 in lung squamous cell carcinoma

BACKGROUND

Lung cancer is one of the most typical cancers in the world. Altered expression profiles of microRNA-375(miR-375) are linked to many diseases including lung cancer. However, the relationship between miR-375 and lung squamous cell carcinoma (LUSC) is controversial.

METHODS

We first evaluated the 23 LUSCs and the paired normal lung tissues by qRT-PCR. Then we analyzed the LUSC samples with miR-375 expression based on The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). Furthermore, bioinformatics analysis was performed to explore the biological role of miR-375 in LUSC.

RESULTS

The expression of miR-375 was remarkably reduced in LUSC tissues compared with that in paired lung tissues by qRT-PCR (P=0.003). Additionally, the TCGA dataset suggested that miR-375 was significantly downregulated in 478 LUSC tissues compared with 45 normal lung tissues (P<0.0001), as well as the result derived from GEO datasets (the pooled SMD=-1.01; 95%CIs-1.66 to -0.33, P=0.004). Furthermore, a total of 1348 miR-375-related differently expressed genes were identified by the analytical integration, which were involved in critical pathways of LUSC like neuron differentiation, plasma membrane part and sequence-specific DNA binding. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway examination also unveiled the involvement of target genes in morphine addiction and drug metabolism- other enzymes and neuroactive ligand-receptor interaction. Finally, the expression of WNT5A was inversely correlated with miR-375 expression according to TCGA dataset (r=-0.2342, P<0.0001).

CONCLUSIONS

miR-375 exerts a strong tumor-suppressive effect in LUSC and provided novel insight into the biological function in tumorigenesis and progression of LUSC.

Diverse roles of miR-335 in development and progression of cancers

MicroRNAs (miRNAs), a series of small noncoding RNAs that regulate gene expression at the post-transcriptional/translational level, are pivotal in cell differentiation, biological development, occurrence, and development of diseases, especially in cancers. Early studies have shown that miRNA-335 (miR-335) is widely dysregulated in human cancers and play critical roles in tumorigenesis and tumor progression. In this review, we aim to summarize the regulation of miR-335 expression mechanisms in cancers. We focus on the target genes regulated by miR-335 and its downstream signaling pathways involved in the biological effects of tumor growth, invasion, and metastasis both in vitro and in vivo, and analyze the relationships between miR-335 expression and the clinical characteristics of tumors as well as its effects on prognosis. The collected evidences support the potential use of miR-335 in prognosis and diagnosis as well as the therapeutic prospects of miR-335 in cancers.

MicroRNAs in glioblastoma multiforme pathogenesis and therapeutics

Glioblastoma multiforme (GBM) is the most common and lethal cancer of the adult brain, remaining incurable with a median survival time of only 15 months. In an effort to identify new targets for GBM diagnostics and therapeutics, recent studies have focused on molecular phenotyping of GBM subtypes. This has resulted in mounting interest in microRNAs (miRNAs) due to their regulatory capacities in both normal development and in pathological conditions such as cancer. miRNAs have a wide range of targets, allowing them to modulate many pathways critical to cancer progression, including proliferation, cell death, metastasis, angiogenesis, and drug resistance. This review explores our current understanding of miRNAs that are differentially modulated and pathologically involved in GBM as well as the current state of miRNA-based therapeutics. As the role of miRNAs in GBM becomes more well understood and novel delivery methods are developed and optimized, miRNA-based therapies could provide a critical step forward in cancer treatment.

Loss-of-function screening to identify miRNAs involved in senescence: tumor suppressor activity of miRNA-335 and its new target CARF

Significance of microRNAs (miRs), small non-coding molecules, has been implicated in a variety of biological processes. Here, we recruited retroviral insertional mutagenesis to obtain induction of an arbitrary noncoding RNAs, and coupled it with a cell based loss-of-function (5-Aza-2′-deoxycytidine (5Aza-dC)-induced senescence bypass) screening system. Cells that escaped 5-Aza-dC-induced senescence were subjected to miR-microarray analysis with respect to the untreated control. We identified miR-335 as one of the upregulated miRs. In order to characterize the functional significance, we overexpressed miR-335 in human cancer cells and found that it caused growth suppression. We demonstrate that the latter accounted for inhibition of 5-Aza-dC incorporation into the cell genome, enabling them to escape from induction of senescence. We also report that CARF (Collaborator of ARF) is a new target of miR-335 that regulates its growth suppressor function by complex crosstalk with other proteins including p16^INK4A, pRB, HDM2 and p21^WAF1.

Understanding the CREB1-miRNA feedback loop in human malignancies

cAMP response element binding protein 1 (CREB1, CREB) is a key transcription factor that mediates transcriptional responses to a variety of growth factors and stress signals. CREB1 has been shown to play a critical role in development and progression of tumors. MicroRNAs (miRNAs) are a class of non-coding RNAs. They post-transcriptionally regulate gene expression through pairing with the 3'-UTR of their target mRNAs and thus regulate initiation and progression of various types of human cancers. Recent studies have demonstrated that a number of miRNAs can be transcriptionally regulated by CREB1. Interestingly, CREB1 expression can also be modulated by miRNAs, thus forming a feedback loop. This review outlines the functional roles of CREB1, miRNA, and their interactions in human malignancies. This will help to define a relationship between CREB1 and miRNA in human cancer and develop novel therapeutic strategies.

MicroRNA-335 is downregulated in bladder cancer and inhibits cell growth, migration and invasion via targeting ROCK1

The expression of microRNA‑335 (miR‑335) has been demonstrated to be downregulated in numerous types of cancer. Thus far, no previous studies have investigated the miR‑335 expression in bladder cancer. In the present study, the expression and effects of miR‑335 were assessed in bladder cancer. The results of the present study provided, to the best of our knowledge, the first evidence that miR‑335 is downregulated in the tumor tissue of patients with bladder cancer. Following transfection of miR‑335, MTT, cell migration and invasion, luciferase and western blot assays were conducted in bladder cancer cell lines. The results demonstrated that miR‑335 inhibited cell proliferation, migration and invasion in T24 and EJ cells. In addition, the results suggested that miR‑335 directly targets Rho‑associated protein kinase 1 (ROCK1) in bladder cancer. The present study provided a novel therapeutic target, the miR‑335/ROCK1 axis in bladder cancer. The suggested approach will be beneficial in developing an effective treatment against bladder cancer.

The Oncogenic Response to MiR-335 Is Associated with Cell Surface Expression of Membrane-Type 1 Matrix Metalloproteinase (MT1-MMP) Activity

MicroRNA miR-335 has been reported to have both tumor suppressor and oncogenic activities. In order to determine possible tissue and cell type differences in response to miR-335, we examined the effect of miR-335 on cell expression of MT1-MMP, a proteinase commonly expressed in tumors and associated with cell proliferation and migration. miR-335 increased cell surface expression of MT1-MMP in fibrosarcoma HT-1080 and benign prostate BPH-1 cells, but not in prostate LNCaP or breast MCF-7 tumor cells. miR-335 stimulated proliferation and cell migration in a wound healing in vitro assay in HT-1080, BPH-1, and U87 glioblastoma cells, cells which demonstrated significant cell surface expression of MT1-MMP. In contrast, miR-335 did not affect proliferation or migration in cells without a prominent plasma membrane associated MT1-MMP activity. Our data suggest that differences in response to miR-335 by tumor cells may lie in part in the mechanism of regulation of MT1-MMP production.