ROCK1 as a potential therapeutic target in osteosarcoma

Cancer cell response to extrinsic and intrinsic mechanical cue: opportunities for tumor apoptosis strategies

Increasing studies have revealed the importance of mechanical cues in tumor progression, invasiveness and drug resistance. During malignant transformation, changes manifest in either the mechanical properties of the tissue or the cellular ability to sense and respond to mechanical signals. The major focus of the review is the subtle correlation between mechanical cues and apoptosis in tumor cells from a mechanobiology perspective. To begin, we focus on the intracellular force, examining the mechanical properties of the cell interior, and outlining the role that the cytoskeleton and intracellular organelle-mediated intracellular forces play in tumor cell apoptosis. This article also elucidates the mechanisms by which extracellular forces guide tumor cell mechanosensing, ultimately triggering the activation of the mechanotransduction pathway and impacting tumor cell apoptosis. Finally, a comprehensive examination of the present status of the design and development of anti-cancer materials targeting mechanotransduction is presented, emphasizing the underlying design principles. Furthermore, the article underscores the need to address several unresolved inquiries to enhance our comprehension of cancer therapeutics that target mechanotransduction.

Signal Pathways and microRNAs in Osteosarcoma Growth and the Dual Role of Mesenchymal Stem Cells in Oncogenesis

The major challenges in Osteosarcoma (OS) therapy are its heterogeneity and drug resistance. The development of new therapeutic approaches to overcome the major growth mechanisms of OS is urgently needed. The search for specific molecular targets and promising innovative approaches in OS therapy, including drug delivery methods, is an urgent problem. Modern regenerative medicine focuses on harnessing the potential of mesenchymal stem cells (MSCs) because they have low immunogenicity. MSCs are important cells that have received considerable attention in cancer research. Currently, new cell-based methods for using MSCs in medicine are being actively investigated and tested, especially as carriers for chemotherapeutics, nanoparticles, and photosensitizers. However, despite the inexhaustible regenerative potential and known anticancer properties of MSCs, they may trigger the development and progression of bone tumors. A better understanding of the complex cellular and molecular mechanisms of OS pathogenesis is essential to identify novel molecular effectors involved in oncogenesis. The current review focuses on signaling pathways and miRNAs involved in the development of OS and describes the role of MSCs in oncogenesis and their potential for antitumor cell-based therapy.

Effect of the Rho-Kinase/ROCK Signaling Pathway on Cytoskeleton Components

The mechanical properties of cells are important in tissue homeostasis and enable cell growth, division, migration and the epithelial-mesenchymal transition. Mechanical properties are determined to a large extent by the cytoskeleton. The cytoskeleton is a complex and dynamic network composed of microfilaments, intermediate filaments and microtubules. These cellular structures confer both cell shape and mechanical properties. The architecture of the networks formed by the cytoskeleton is regulated by several pathways, a key one being the Rho-kinase/ROCK signaling pathway. This review describes the role of ROCK (Rho-associated coiled-coil forming kinase) and how it mediates effects on the key components of the cytoskeleton that are critical for cell behaviour.

ERK phosphorylation is dependent on cell adhesion in a subset of pediatric sarcoma cell lines

Osteosarcoma (OS) and Pax-Foxo1 fusion negative rhabdomyosarcoma (FN-RMS) are pediatric sarcomas with poor prognoses in patients with advanced disease. In both malignancies, an actin binding protein has been linked to poor prognosis. Integrin adhesion complexes (IACs) are closely coupled to actin networks and IAC-mediated signaling has been implicated in the progression of carcinomas. However, the relationship of IACs and actin cytoskeleton remodeling with cell signaling is understudied in pediatric sarcomas. Here, we tested the hypothesis that IAC dynamics affect ERK activation in OS and FN-RMS cell lines. Adhesion dependence of ERK activation differed among the OS and FN-RMS cells examined. In the OS cell lines, adhesion did not have a consistent effect on phospho-ERK (pERK). ERK phosphorylation in response to fetal calf serum or 1 ng/ml EGF was nearly as efficient in OS cell lines and one FN-RMS cell line in suspension as cells adherent to poly-l-lysine (PL) or fibronectin (FN). By contrast, adhesion to plastic, PL or FN increased ERK phosphorylation and was greater than additive with a 15 min exposure to 1 ng/ml EGF in three FN-RMS cell lines. Increases in pERK were partly dependent on FAK and PAK1/2 but independent of IAC maturation. As far as we are aware, this examination of adhesion-dependent signaling is the first in pediatric sarcomas and has led to the discovery of differences from the prevailing paradigms and differences in the degree of coupling between components in the signaling pathways among the cell lines.

The role of miR-129-5p in cancer: a novel therapeutic target

MiRNA-129-5p belongs to the microRNA-129 (miRNA-129) family. MiRNA-129-5p is expressed in many tissues and organs of the human body, and it regulates a wide range of biological functions. The abnormal expression of miRNA-129-5p is related to the occurrence and development of a variety of malignant tumors. MiRNA-129-5p plays an important role in the tumorigenesis process and functions by promoting or inhibiting tumors. However, the role of miRNA-129-5p in cancer remains controversial. This article reviews the different biological functions of miRNA-129-5p in cancer and provides ideas for research in this field to guide the development of targeted therapies and drugs for malignant tumors.

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

BACKGROUND

Sevoflurane (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.

METHODS

Liver 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.

RESULTS

SEVO 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.

CONCLUSION

Our 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.

The Roles of Tissue Rigidity and Its Underlying Mechanisms in Promoting Tumor Growth

Tissues become more rigid during tumorigenesis and have been identified as a driving factor for tumor growth. Here, we highlight the concept of tissue rigidity, contributing factors that increase tissue rigidity, and mechanisms that promote tumor growth initiated by increased tissue rigidity. Various factors lead to increased tissue rigidity, promoting tumor growth by activating focal adhesion kinase (FAK) and Rho-associated kinase (ROCK). Consequently, result in recruitment of cancer-associated fibroblasts (CAFs), epithelial-mesenchymal transition (EMT) and tumor protection from immunosurveillance. We also discussed the rationale for targeting tumor tissue rigidity and its potential for cancer treatment.

Should we keep rocking? Portraits from targeting Rho kinases in cancer

Cancer targeted therapy, either alone or in combination with conventional chemotherapy, could allow the survival of patients with neoplasms currently considered incurable. In recent years, the dysregulation of the Rho-associated coiled-coil kinases (ROCK1 and ROCK2) has been associated with increased metastasis and poorer patient survival in several tumor types, and due to their essential roles in regulating the cytoskeleton, have gained popularity and progressively been researched as targets for the development of novel anti-cancer drugs. Nevertheless, in a pediatric scenario, the influence of both isoforms on prognosis remains a controversial issue. In this review, we summarize the functions of ROCKs, compile their roles in human cancer and their value as prognostic factors in both, adult and pediatric cancer. Moreover, we provide the up-to-date advances on their pharmacological inhibition in pre-clinical models and clinical trials. Alternatively, we highlight and discuss detrimental effects of ROCK inhibition provoked not only by the action on off-targets, but most importantly, by pro-survival effects on cancer stem cells, dormant cells, and circulating tumor cells, along with cell-context or microenvironment-dependent contradictory responses. Together these drawbacks represent a risk for cancer cell dissemination and metastasis after anti-ROCK intervention, a caveat that should concern scientists and clinicians.

LncRNA LINK-A regulates ROCK1 expression in early-stage pancreatic adenocarcinoma

Long intergenic non-coding RNA for kinase activation (LINK-A) has been characterized as an oncogenic long non-coding (lnc)RNA in triple-negative breast cancer and ovarian carcinoma, but its involvement in other malignancies remains elusive. In the present study, it was determined that the plasma levels of LINK-A lncRNA and Rho-associated protein kinase 1 (ROCK1) were significantly increased in patients with pancreatic adenocarcinoma compared with those in healthy controls. The plasma levels of LINK-A lncRNA were positively correlated with the plasma levels of ROCK1 in pancreatic adenocarcinoma patients, but not in healthy controls. Silencing of LINK-A led to inhibition of pancreatic adenocarcinoma cell proliferation, migration and invasion. Simultaneous overexpression of ROCK1 attenuated the inhibitory effect of LINK-A silencing on cancer cell proliferation, migration and invasion. Overexpression of LINK-A lncRNA led to upregulation of ROCK1 expression, while overexpression of ROCK1 had no significant effect on LINK-A lncRNA expression. It may therefore be concluded that LINK-A lncRNA may have a role in pancreatic adenocarcinoma, at least in part, by promoting ROCK1 expression.

6-Substituted purines as ROCK inhibitors with anti-metastatic activity

Rho-associated serine/threonine kinases (ROCKs) are principal regulators of the actin cytoskeleton that regulate the contractility, shape, motility, and invasion of cells. We explored the relationships between structure and anti-ROCK2 activity in a group of purine derivatives substituted at the C6 atom by piperidin-1-yl or azepan-1-yl groups. Structure-activity relationship (SAR) analyses suggested that anti-ROCK activity is retained, and may be further increased, by substitution of the parent compounds at the C2 atom or by expansion of the C6 side chain. These inhibitors of ROCK can reach effective concentrations within cells, as demonstrated by a decrease in phosphorylation of the ROCK target MLC, and by inhibition of the ROCK-dependent invasion of melanoma cells in the collagen matrix. Our study may be useful for further optimization of C6-substituted purine inhibitors of ROCKs and of other sensitive kinases identified by the screening of a broad panel of protein kinases.

Serum ROCK1 mRNA is of great diagnostic value for glioma patients

The study aimed to measure the presence of rho-associated protein kinase 1 (ROCK1) mRNA in serum samples collected from glioma and investigate its diagnostic significance in glioma.The presence of ROCK1 mRNA was examined by quantitative real-time polymerase chain reaction (qRT-PCR). The relationship between ROCK1 mRNA and clinical characteristics was analyzed via Chi-square test. The criteria of diagnosis evaluation, including sensitivity, specificity, optimal cutoff point, and area under the curve (AUC) were determined through the receiver operating characteristic (ROC) curve analysis.ROCK1 mRNA was significantly increased in serum samples collected from glioma patients compared to the controls (P <.05). Besides, high ROCK1 mRNA expression was tightly related with Karnofsky Performance Status (KPS) score (P = .024) and World Health Organization (WHO) grade (P = .029). However, there was no association between ROCK1 expression and gender, neurological disorders, family history and cigarette smoking (all, P >.05). In addition, the optimal cutoff point was 3.025, with the sensitivity and specificity of 88.89% and 79.25%, respectively. The AUC was 0.881, indicating that ROCK1 was a diagnostic biomarker for glioma patients (P <.0001, 95% CI = 0.829-0.933).Serum ROCK1 mRNA is significantly up-regulated in glioma cases compared to healthy controls. ROCK1 may be a potential diagnostic biomarker in glioma.

ROCK Inhibition Induces Terminal Adipocyte Differentiation and Suppresses Tumorigenesis in Chemoresistant Osteosarcoma Cells

Tumors comprise heterogeneous cell types including cancer stem cells (CSC), progenitor cells, and differentiated cells. Chemoresistance is a potential cause of relapse and a key characteristic of CSC, but the development of novel therapeutic approaches for targeting these cells has been limited. We previously established osteosarcoma-initiating (OSi) cells by introducing the gene for c-Myc into bone marrow stromal cells of Ink4a/Arf knockout mice. These OSi cells are composed of two distinct clones: highly tumorigenic cells (AX cells), similar to bipotent committed osteochondral progenitor cells, and tripotent cells of low tumorigenicity (AO cells), similar to mesenchymal stem cells. Here we show that depolymerization of the actin cytoskeleton induces terminal adipocyte differentiation and suppresses tumorigenesis in chemoresistant OSi cells. In contrast to AX cells, AO cells were highly resistant to conventional chemotherapeutic agents such as doxorubicin and were thus identified as chemoresistant cells. Inhibition of Rho-associated coiled-coil containing protein kinase (ROCK) elicited terminal adipocyte differentiation in chemoresistant AO cells through negative regulation of the transcriptional coactivator megakaryoblastic leukemia 1 associated with actin depolymerization. The clinically administered ROCK inhibitor fasudil significantly suppressed growth in vitro and tumorigenicity in vivo of chemoresistant AO cells as well as of OSi cells. Our findings thus suggest a new therapeutic strategy based on the induction of trans-terminal differentiation via modulation of actin cytoskeleton dynamics for therapy-resistant osteosarcoma stem cells. SIGNIFICANCE: These findings suggest that induction of trans-terminal differentiation through regulation of actin dynamics is a potential novel therapeutic approach for targeting chemoresistant stem-like tumor cells.

microRNA-138-5p as a Worse Prognosis Biomarker in Pediatric, Adolescent, and Young Adult Osteosarcoma

Osteosarcoma (OS) is the most common primary malignant bone tumor with two peaks of incidence, in early adolescence and the elderly. Patients affected with this malignancy often present metastatic disease at diagnosis, and despite multimodality therapy, survival has not improved substantially over the past 3 decades. Recently, miR-138-5p, proposed as a crucial intracellular mediator of invasion, has been recognized to target the Rho-associated coiled-coil containing protein kinase 2 (ROCK2). Dysregulation of ROCK1 and ROCK2 was also described in OS, being associated to higher metastasis incidence and worse prognosis. Nonetheless, the specific roles of miR-138-5p in pediatric and young adult OS and its ability to modulate these kinases remain to be established. Thus, in the present study, the expression levels miR-138-5p were evaluated in a consecutive cohort of exclusively pediatric and young adult primary OS samples. In contrast to previous reports that included adult tissues, our results showed upregulation of miR-138-5p associated with reduced event-free survival and relapsed cases. In parallel, ROCK1 mRNA levels were significantly reduced in tumor samples and negatively correlated with miR-138-5p. Similar correlations were observed after studying the profiles of ROCK1 and ROCK2 by immunohistochemistry. Our data present miR-138-5p as a consistent prognostic factor in pediatric and young adult OS, reinforcing its participation in the post-transcriptional regulation of ROCK kinases.

EPEL promotes the migration and invasion of osteosarcoma cells by upregulating ROCK1

E2F-mediated cell proliferation enhancing long non-coding RNA (lncRNA) (EPEL) is a newly identified lncRNA involved in the regulation of lung cancer cell proliferation. However, its association with other types of cancer is unknown. The present study recruited patients with osteosarcoma and healthy controls. Tumor and adjacent healthy tissues were obtained from patients with osteosarcoma, and whole blood was extracted from patients and healthy controls. The expression levels of EPEL in tissues were detected by reverse transcription-quantitative polymerase chain reaction. The diagnostic value of serum EPEL for osteosarcoma was evaluated by receiver operating characteristic curve analysis. The association between serum levels of EPEL and basic clinical patient information was analyzed by χ² test. Subsequently, EPEL overexpression in osteosarcoma cell lines was established, and its effects on cell migration and invasion were explored by Transwell assay. The implications of EPEL overexpression on Rho-associated coiled-coil containing protein kinase 1 (ROCK1) expression were investigated by western blotting. The results revealed that EPEL was upregulated in tumor tissues compared with adjacent tissues. In addition, serum levels of EPEL were higher in patients with osteosarcoma compared with healthy controls, and were positively associated with distant tumor metastasis. Furthermore, EPEL overexpression promoted the migration and invasion of osteosarcoma cells and induced overexpression of ROCK1. In conclusion, these results suggested that EPEL may promote the migration and invasion of osteosarcoma cells by upregulating ROCK1.

Identification of candidate neoantigens produced by fusion transcripts in human osteosarcomas

Osteosarcomas are characterized by highly disrupted genomes. Although osteosarcomas lack common fusions, we find evidence of many tumour specific gene-gene fusion transcripts, likely due to chromosomal rearrangements and expression of transcription-induced chimeras. Most of the fusions result in out-of-frame transcripts, potentially capable of producing long novel protein sequences and a plethora of neoantigens. To identify fusions, we explored RNA-sequencing data to obtain detailed knowledge of transcribed fusions, by creating a novel program to compare fusions identified by deFuse to de novo transcripts generated by Trinity. This allowed us to confirm the deFuse results and identify unusual splicing patterns associated with fusion events. Using various existing tools combined with this custom program, we developed a pipeline for the identification of fusion transcripts applicable as targets for immunotherapy. In addition to identifying candidate neoantigens associated with fusions, we were able to use the pipeline to establish a method for measuring the frequency of fusion events, which correlated to patient outcome, as well as highlight some similarities between canine and human osteosarcomas. The results of this study of osteosarcomas underscores the numerous benefits associated with conducting a thorough analysis of fusion events within cancer samples.

MiR-144 Inhibits Tumor Growth and Metastasis in Osteosarcoma via Dual-suppressing RhoA/ROCK1 Signaling Pathway

Several microRNAs (miRNAs) have been found expressed differentially in osteosarcoma (OS), so they may function in the onset and progression of OS. In this study, we found that miR-144 significantly suppresses osteosarcoma cell proliferation, migration, and invasion ability in vitro and inhibited tumor growth and metastasis in vivo. Mechanically, we demonstrated that Ras homolog family member A (RhoA) and its pivotal downstream effector Rho-associated, coiled-coil-containing protein kinase 1 (ROCK1) were direct targets of miR-144. Moreover, the negative correlation between down-regulated miR-144 and up-regulated ROCK1/RhoA was verified in both OS cell lines and clinical patients' specimens. Functionally, RhoA with or without ROCK1 co-overexpression resulted a rescue phenotype on miR-144 inhibited cell growth, migration, and invasion abilities whereas individual overexpression of ROCK1 had no statistical significance compared with controls in miR-144-transfected SAOS2 and U2-OS cells. Taken together, this study demonstrates that miR-144 inhibited tumor growth and metastasis in OS via dual-suppressing of RhoA and ROCK1, which could be a new therapeutic approach for the treatment of OS.

lncRNA SNHG1 negatively regulates miRNA‑101‑3p to enhance the expression of ROCK1 and promote cell proliferation, migration and invasion in osteosarcoma

Osteosarcoma (OS) is a rare malignant bone tumor that commonly occurs in children and adolescents and causes pain and swelling of the long bones of the legs and arms. Long non-coding RNA (lncRNA) and micro (mi)RNA-101 are important in the initialization and progression of OS. However, the mechanism underlying the role of the lncRNA and miRNA-101 in OS remains to be fully elucidated. In the present study, through reverse transcription-quantitative polymerase chain reaction analysis, it was first found that the lncRNA SNHG1 was upregulated and miRNA-101-3p was downregulated in OS tissues and cell lines. Second, the knockdown of lncRNA SNHG1 induced cell apoptosis and maintained the cell cycle at the G0/G1 phase, which decreased the overall cell viability. Furthermore, according to a dual-luciferase assay and western blot analysis, miRNA-101-3p was found to be a target of the lncRNA SNHG1 in OS, which further regulated the expression of Rho-associated coiled-coil-containing protein kinase 1 (ROCK1). It was found that the phosphoinositide 3-kinase/ATK pathway was inactivated and that epithelial-mesenchymal transition was activated in OS cell lines with overexpression of the lncRNA SNHG1. Taken together, in OS cell lines, the lncRNA SNHG1 acted as an oncogene, and miRNA-101-3p was considered a tumor suppressor. The lncRNA SNHG1 promoted OS cell proliferation, migration and invasion by downregulating the expression of miRNA-101-3p, which enhanced the expression of ROCK1.

ARHGEF10L contributes to liver tumorigenesis through RhoA-ROCK1 signaling and the epithelial-mesenchymal transition

Aberrant activity of Rho small G-proteins and their regulators plays an important role in tumorigenesis. Rho guanine nucleotide exchange factor 10-Like (ARHGEF10L) is a member of the RhoGEF family that promotes the active GTP-bound state of Rho GTPases. This study used the Illumina GoldenGate microassay, Sequenom MassARRAY and TaqMan to analyze possible correlations between tag single nucleotide polymorphisms (tag SNPs) in the ARHGEF10L locus and various tumor risks. The genotyping analyses demonstrated a strong association of rs2244444 and rs12732894 with liver cancer. Western blotting and immunohistochemistry also revealed increased expression of ARHGEF10L in hepatocellular carcinoma tissues. Furthermore, increased cell proliferation, cell migration and RhoA activity; increased expression of Rho-associated coiled-coil kinase-1 (ROCK1), phospho- Ezrin/Radixin/Moesin (ERM), vimentin, N-cadherin and Slug, and decreased E-cadherin expression were detected in hepatocellular carcinoma cell Bel-7402 and HepG2 cells with transfection of ARHGEF10L-expressing plasmids. Opposite results were obtained in the two cell lines with transfection of anti-ARHGEF10L siRNA. Tumor-bearing mice were generated with Bel-7402 cells transfected with lentivirus vectors packaging short hairpin ARHGEF10L RNA. The xenograft tumors with the inhibited ARHGEF10L expression showed decreased tumor growth and expression of vimentin, N-cadherin and Slug. Additionally, decreased phospho-ERM expression was detected in Bel-7402 and HepG2 cells with transfection of anti-ROCK1 siRNA and increased expression of ROCK1 was detected in hepatocellular carcinoma tissues. E-cadherin, vimentin, N-cadherin and Slug are markers of the epithelial-to-mesenchymal transition (EMT). ROCK1, phospho-ERM and EMT have been reported to promote tumor cell proliferation, metastasis and angiogenesis. Our study suggests that increased expression of ARHGEF10L stimulates hepatocellular tumorigenesis by activating the RhoA-ROCK1- phospho ERM pathway and EMT.

Long non-coding RNA SNHG5 sponges miR-26a to promote the tumorigenesis of osteosarcoma by targeting ROCK1

BACKGROUND

Osteosarcoma (OS) is one of the most common invasive malignancies of the bone. The long non-coding RNA (lncRNA) SNHG5 (small nucleolar RNA host gene 5) has been consistently shown to be involved in many cancers, although its precise function in osteosarcoma remains poorly understood. In this study, we investigated the role of SNHG5 in OS progression and the underlying mechanism.

METHODS

SNHG5 expression in 32 OS tissues and 4 OS cell lines was measured by quantitative real-time PCR (qRT-PCR). Migration, invasion, proliferation and cell cycle profiles were analyzed by established assays to determine the biological functions of SNHG5 and miR-26a in OS cells. The binding sites of miR-26a in SNHG5 and ROCK1 were predicted by the RNAhybrid 2.2 program. Luciferase reporter assay was then used to validate the direct targeting of SNHG5 with miR-26a and of Rho-associated coiled coil-containing protein kinase 1 (ROCK1) with miR-26a. The effect of SNHG5 on the ROCK signaling pathway was assessed by western blotting.

RESULTS

Elevated expression of SNHG5 was correlated with poor clinical outcome and prognosis in OS patients. SNHG5 functioned as a sponge for miR-26a and promoted proliferation, invasion and migration, and accelerated G1 to S phase transition in OS cells. SNHG5 functioned as a competing endogenous RNA (ceRNA) for miR-26a and activated the ROCK signaling pathway through the miR-26a-ROCK1 axis.

CONCLUSION

SNHG5 acts as an oncogene in OS via the SNHG5-miR-26a-ROCK1 axis and is therefore a potential novel therapeutic target for OS treatment.

Suppression of focal adhesion formation may account for the suppression of cell migration, invasion and growth of non-small cell lung cancer cells following treatment with polyisoprenylated cysteinyl amide inhibitors

Migratory cells form extracellular matrix attachments called focal-adhesions. Focal adhesion assembly and disassembly are regulated by the Rho family of small GTPases. We previously reported that polyisoprenylated cysteinyl amide inhibitors (PCAIs) suppress Rho protein levels, disrupting F-actin cytoskeleton remodeling in the formation of lamellipodia and filopodia. In this study, we investigated whether these observations effect focal adhesion formation, which involves cell surface receptors known as integrins and several signaling/adaptor proteins such as vinculin, α-actinin, Rock kinases and phospho-Myosin Light Chain-2 (p-MLC-2), that foster the linkage of the actin cytoskeleton to the extracellular matrix. We observed that treatment of H1299 cells with 5 μM PCAIs for 24 h markedly diminished the level of full-length integrin α4 by at least 24% relative to controls. PCAIs at 5 μM, diminished the levels of vinculin by at least 50%. Immunofluorescent analysis showed at least a 76% decrease in the number of vinculin-focal adhesion punctates. In addition, PCAIs diminished Rock1 levels by 25% and its substrate, p-MLC-2 by 75%. PCAIs did not significantly alter the levels of integrin β5, α-actinin, and Rock2, suggesting that the effects of the PCAIs are target specific. Our data indicate that the PCAIs alter the levels of the Rho proteins and their effectors to abrogate their functions in cytoskeleton remodeling thereby suppressing focal adhesion formation. This in turn results in a PCAIs-induced decrease in cell invasion, thus making the PCAIs propitious agents for the inhibition of cancer growth and metastasis.

miR-202-5p inhibits the migration and invasion of osteosarcoma cells by targeting ROCK1

Many studies have shown that microRNA regulates the development and treatment of osteosarcoma (OS). In many human cancer studies, the expression of microRNA-202 has been shown to be abnormal. The aim of the study was to examine the role of miR-202-5p in the occurrence and formation of OS. miR-202-5p and Rho-associated coiled-coil containing protein kinase 1 (ROCK1) levels were assessed using RT-qPCR in OS tissues and cell lines. The cell migrating and invasive abilities were detected by the Transwell assay in OS. Moreover, the relationship between miR-202-5p and ROCK1 was verified via luciferase reporter assay. The protein level of ROCK1 was identified by western blot analysis. Downregulation of miR-202-5p was identified in OS tissues and cell lines. In addition, the miR-202-5p overexpression had inhibitory action for cell migration and invasion in OS. Moreover, miR-202-5p directly targeted ROCK1 and negatively regulated its expression. Upregulation of ROCK1 had a carcinogenic effect in OS. Furthermore, the upregulation of ROCK1 restored the suppressive effect of miR-202-5p. miR-202-5p, in turn, weakened the abilities of cell migration and invasion in OS by inhibiting ROCK1 expression. As a result, miR-202-5p may be developed as a potential pathway in the reatment of OS.

Prognostic value and functional role of ROCK2 in pediatric Ewing sarcoma

Ewing's sarcoma (EWS) is a highly aggressive bone cancer that affects children and adolescents. Despite advances in multimodal management, 5-year event-free survival rates for patients presenting with metastases at diagnosis remain at 25%. As key regulators of actin organization, the Rho-associated coiled-coil containing protein kinases, ROCK1 and ROCK2, have been associated with cancer dissemination and poorer prognosis. Recently, in vitro data indicating ROCK2 as a molecular target for the treatment of EWS has been presented. Nonetheless, a deeper exploration of the contribution of this kinase dysregulation in EWS is still necessary. In this regard, the present study aimed to evaluate the expression of ROCK1 and ROCK2 in 23 pediatric tumor samples and to verify the prospect of using their pharmacological inhibition through functional assays. Our results showed positive immunostaining for ROCK1 and ROCK2 in the majority samples (75 and 65%, respectively). A significantly increased risk of incomplete remission in patients with positive immunostaining for ROCK2 was found (P=0.026), though no correlations with other prognostic features (huvos classification, FLI1/EWS status, relapse, metastasis or death) were observed. Associations with survival were merely suggestive. Apparent protein expression of both kinases was also found in EWS cell lines (SK-ES-1 and RD-ES). Treatments with selective ROCK inhibitors did not alter cell viability or migration in vitro. However, a significant increase in invasion was observed after treatment with SR3677 (ROCK2 inhibitor) and hydroxyfasudil (pan-inhibitor). Consequently, even though the majority of EWS samples included in our study showed positivity for ROCK1 and ROCK2, the lack of significant associations with prognosis and absence of appropriate responses to their inhibition in vitro does not support their prospective use as therapeutic targets for the treatment of this metastatic tumor. Larger cohort studies might provide more evidence on whether there is a specific role of ROCK kinases in EWS physiopathology.

MicroRNA-129-5p suppresses cell proliferation, migration and invasion via targeting ROCK1 in osteosarcoma

Osteosarcoma (OS) is the most common primary malignancy of the bone in teenagers and accounts for 20‑35% of all malignant primary bone tumors. Increasing evidence shows that microRNAs (miRNAs) are abnormally expressed in several types of human cancer. miRNAs are necessary to maintain the malignant phenotype of cancer cells and can function as either tumor suppressors or oncogenes. The present study aimed to measure the expression of miRNA‑129‑5p (miR‑129‑5p) in OS, determine the effects of miR‑129‑5p on the malignant behaviors of OS cells, and elucidate the molecular mechanism underlying the oncogenesis and progression of OS. The expression levels of miR‑129‑5p in OS tissues and cell lines were measured using reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analysis. SAOS‑2 and U2OS cells were then transfected with miR‑129‑5p mimics or miR‑negative control. The effects of miR‑129‑5p on the proliferation, migration and invasion of SAOS‑2 and U2OS cells in vitro were then evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, Transwell migration assay and invasion assays, respectively. In addition, bioinformatics analysis, a luciferase reporter assay, and RT‑qPCR and western blot analyses were used to examine whether Rho‑associated protein kinase 1 (ROCK1) was a direct target of miR‑129‑5p. The mRNA expression of ROCK1 in OS tissues was detected using RT‑qPCR analysis, and the biological roles of ROCK1 in OS cells were also evaluated. The results showed that miR‑129‑5p was significantly downregulated in the OS tissues and cell lines. The re‑expression of miR‑129‑5p suppressed the cell proliferation, migration and invasion of OS cells. In addition, ROCK1 was confirmed as a direct target of miR‑129‑5p. The mRNA expression of ROCK1 was high in OS tissues and inversely correlated with the expression of miR‑129‑5p. The downregulation of ROCK1 inhibited the proliferation, migration and invasion of OS cells. These findings suggested that miR‑129‑5p inhibited cell proliferation, migration and invasion in the development of OS via the negative regulation of ROCK1. The miR‑129‑5p/ROCK1 axis may serve as an efficient target in cancer therapy.

Inhibitors of Rho kinase (ROCK) signaling revert the malignant phenotype of breast cancer cells in 3D context

Loss of polarity and quiescence along with increased cellular invasiveness are associated with breast tumor progression. ROCK plays a central role in actin-cytoskeletal rearrangement. We used physiologically relevant 3D cultures of nonmalignant and cancer cells in gels made of laminin-rich extracellular matrix, to investigate ROCK function. Whereas expression levels of ROCK1 and ROCK2 were elevated in cancer cells compared to nonmalignant cells, this was not observed in 2D cultures. Malignant cells showed increased phosphorylation of MLC, corresponding to disorganized F-actin. Inhibition of ROCK signaling restored polarity, decreased disorganization of F-actin, and led to reduction of proliferation. Inhibition of ROCK also decreased EGFR and Integrinβ1 levels, and consequently suppressed activation of Akt, MAPK and FAK as well as GLUT3 and LDHA levels. Again, ROCK inhibition did not inhibit these molecules in 2D. A triple negative breast cancer cell line, which lacks E-cadherin, had high levels of ROCK but was less sensitive to ROCK inhibitors. Exogenous overexpression of E-cadherin, however, rendered these cells strikingly sensitive to ROCK inhibition. Our results add to the growing literature that demonstrate the importance of context and tissue architecture in determining not only regulation of normal and malignant phenotypes but also drug response.

Inhibition of X-linked inhibitor of apoptosis protein suppresses tumorigenesis and enhances chemosensitivity in anaplastic thyroid carcinoma

Anaplastic thyroid carcinoma (ATC) is one of the most lethal carcinoma with a poor prognosis; however, molecular mechanisms underlying the aggressiveness of ATC remain unclear. Our goal was to examine the expression of X-linked inhibitor of apoptosis protein (XIAP) in ATC, as well as its role in ATC tumorigenesis. This is a retrospective study of ATC patients from the Second Affiliated Hospital of Harbin Medical University during June 2003 to October 2013. The expression of XIAP in tumor specimens of ATC patients was examined by immunohistochemical staining. The roles of XIAP in proliferation, migration, invasion, and chemoresistance were investigated by shRNA mediated-knockdown of XIAP in human ATC cell lines. The effect of XIAP on tumorigenesis was evaluated using a xenograft tumor model with nude mice. XIAP expression was significantly higher in the invasive area of ATC samples, whereas XIAP expression was negative in either normal thyroid follicular epithelial cells or the differentiated papillary thyroid carcinoma. XIAP-depleted ATC cells showed a remarkable decrease in the proliferation, migration, and invasion compared with the scramble group. Knockdown of XIAP expression significantly enhanced the chemosensitivity of WRO and SW1736 cells to docetaxel or taxane. Moreover, knockdown of XIAP significantly suppressed ATC tumorigenesis in vivo. XIAP is highly expressed in ATC cells and tumors. XIAP play important roles in tumor behaviors and chemosensitivity of ATC cells. XIAP may function in ATC aggressiveness and may serve as a potential therapeutic target for ATC treatment.

Inhibition of ROCK1 kinase modulates both tumor cells and stromal fibroblasts in pancreatic cancer

ROCK, or Rho-associated coiled coil-containing protein kinase, is a member of the AGC kinase family and has been shown to play a role in cell migration, ECM synthesis, stress-fiber assembly, and cell contraction. Increased ROCK expression has been reported in multiple pathological conditions, including cancer. Here, we report increased expression of ROCK 1 in pancreatic tumor epithelial cells as well as in cancer associated fibroblasts (CAF). In our analysis, 62% of tumor samples exhibited ≥2+ in staining intensity by IHC analysis, versus 40% of adjacent normal tissue samples (P<0.0001). Thus, we hypothesized that ROCKs may play a significant role in pancreatic cancer progression, and may serve as a suitable target for treatment. We report a low frequency (4/34) amplification of the ROCK1 gene locus at chromosome 18q11.1 in pancreatic ductal adenocarcinoma (PDAC) patient tissue samples by aCGH analysis. Inhibition of ROCK kinase activity by a small molecule inhibitor (fasudil) resulted in moderate (IC50s of 6-71 μM) inhibition of PDAC cell proliferation, migration, and activation of co-cultured stellate cells. In the KPC mouse model for pancreatic cancer, fasudil decreased tumor collagen deposition. This translated to an enhanced overall survival of the mice and an increase in gemcitabine uptake. Though fasudil may target both the tumor epithelial cells and the CAFs, our findings are consistent with the hypothesis that inhibition of tumor stroma enhances drug penetration and efficacy in PDAC. Overall, our data suggests that ROCK1 may serve as a potential therapeutic target to enhance current treatment regimens for pancreatic cancer.

Activation of the ROCK1/MMP-9 pathway is associated with the invasion and poor prognosis in papillary thyroid carcinoma

Rho-associated protein kinase 1 (ROCK1), a serine/threonine kinase, has previously been shown to be over-expressed in various types of human malignant tumors and to play an important role in cancer development and progression. Although ROCK1 has gained growing prominence as an important protein kinase in cancer biology, its potential as a predictive biomarker and a therapeutic target in papillary thyroid carcinoma (PTC) remains unknown. In the present study, ROCK1 expression was examined in 356 formalin-fixed, paraffin-embedded papillary thyroid carcinoma tissues using immunohistochemistry, and its clinical implications and prognostic significance were analyzed. Our results showed that ROCK1 expression was significantly increased in PTC compared with normal tissues, and was significantly associated with tumor size, lymphatic metastasis, distant organ metastasis, extrathyroid invasion, vascular invasion and tumor, node and metastasis (TNM) stage. Patients with strong ROCK1 expression had lower overall survival, disease-free survival, lymph node recurrence-free survival and distant recurrence-free survival rates than those with weak expression. Furthermore, overexpression of ROCK1 in papillary thyroid carcinoma cells was found to increase their invasiveness. Silencing ROCK1 by siRNA, however, caused an inhibition of cell invasion. Knockdown of ROCK1 decreased the volume and weight of the xenograft tumors, while overexpression of ROCK1 showed a proliferative tendency with significantly greater tumor volume and weight in vivo. Moreover, the upregulation of ROCK1 increased the expression of MMP-9, and levels of MMP-9 positively correlated with the ROCK1 levels in PTC tissues, implicating that MMP-9 may be involved in the mechanism of ROCK1 in the development and progression of PTC. These data suggest that ROCK1 might be a potential prognostic marker and therapeutic target for the treatment of PTC.

Downregulation of BZW2 inhibits osteosarcoma cell growth by inactivating the Akt/mTOR signaling pathway

Osteosarcoma is the most common malignant bone tumor in adolescents. The function of basic leucine zipper and W2 domains 2 (BZW2) in tumor progression has been reported. However, the role and mechanisms of BZW2 in osteosarcoma remain to be determined. The aim of the present study was to reveal the expression and biological functions of BZW2 in osteosarcoma and to elucidate the proximal mechanisms underlying these functions. The expression of BZW2 in osteosarcoma tissues and cell lines was assessed by qRT-PCR, western blotting and immunohistochemistry. BZW2 overexpression was detected in osteosarcoma cell lines. Clinically, BZW2 expression was higher in osteosarcoma tissues than in corresponding non-tumor tissues and was associated with advanced Enneking stage and tumor recurrence. The knockdown of BZW2 using siRNA inhibited osteosarcoma cell proliferation, colony-forming ability, and the cell cycle at the G2/M phase in vitro. Host signaling pathways affected by BZW2 were detected using a PathScan Intracellular Signaling Antibody Array kit. These data demonstrated that the knockdown of BZW2 suppresses protein phosphorylation in the Akt/mTOR signaling pathway. These observations suggest that BZW2 is upregulated and has a pro-tumor effect in osteosarcoma via activation of the Akt/mTOR signaling pathway and thus is a potential target for gene therapy.

Rho kinase proteins display aberrant upregulation in vascular tumors and contribute to vascular tumor growth

BACKGROUND

The serine/threonine protein kinases ROCK1 and 2 are key RhoA-mediated regulators of cell shape and cytoskeletal dynamics. These proteins perform multiple functions in vascular endothelial cell physiology and are attractive targets for cancer therapy based on their roles as oncogenes and metastatic promoters. Given their critical functions in both of these processes, we hypothesized that molecular targeting of ROCK proteins would be exceedingly effective against vascular tumors such as hemangiomas and angiosarcomas, which are neoplasms composed of aberrant endothelial cells.

METHODS

In this study, we compared ROCK1 and 2 protein expression in a large panel of benign and malignant vascular tumors to that of normal vasculature. We then utilized shRNA technology to knockdown the expression of ROCK1 and 2 in SVR tumor-forming vascular cells, and evaluated tumor size and proliferation rate in a xenograft model. Finally, we employed proteomics and metabolomics to assess how knockdown of the ROCK paralogs induced alterations in protein expression/phosphorylation and metabolite concentrations in the xenograft tumors.

RESULTS

Our findings revealed that ROCK1 was overexpressed in malignant vascular tumors such as hemangioendotheliomas and angiosarcomas, and ROCK2 was overexpressed in both benign and malignant vascular tumors including hemangiomas, hemangioendotheliomas, hemangiopericytomas, and angiosarcomas. shRNA-mediated knockdown of ROCK2, but not ROCK1, in xenograft vascular tumors significantly reduced tumor size and proliferative index compared to control tumors. Proteomics and metabolomics analysis of the xenograft tumors revealed both overlapping as well as unique roles for the ROCK paralogs in regulating signal transduction and metabolite concentrations.

CONCLUSIONS

Collectively, these data indicate that ROCK proteins are overexpressed in diverse vascular tumors and suggest that specific targeting of ROCK2 proteins may show efficacy against malignant vascular tumors.

miR-214-5p Targets ROCK1 and Suppresses Proliferation and Invasion of Human Osteosarcoma Cells

MicroRNAs (miRNAs) are small conserved RNAs regulating specific target genes in posttranscriptional levels. They have been involved in multiple processes of tumor progression, including cell proliferation. miR-214-5p (also miR-214*) is a newly identified miRNA, and its functions are largely unknown. In this study, we explore the role of miR-214-5p in the proliferation and invasion of human osteosarcoma (OS) cells. The results showed that miR-214-5p was sharply reduced in OS tissues and cell lines, compared with normal tissues and cell lines. In addition, the miR-214-5p mimic greatly increased the miR-214-5p level and significantly decreased the proliferation and invasion of HOS and G293 OS cells. In contrast, the miR-214-5p inhibitor had a completely opposite effect on the miR-214-5p level, cell proliferation, and cell invasion. Moreover, bioinformatics and luciferase reporter gene assays confirmed that miR-1908 targeted the mRNA 3'-UTR region of ROCK1, a characterized tumor promoter in OS. In conclusion, miR-214-5p was identified as a new tumor suppressor, which directly targeted ROCK1 and suppressed proliferation of human OS cells.

MicroRNA-335 and its target Rock1 synergistically influence tumor progression and prognosis in osteosarcoma

MicroRNA (miR)-335 and Rho-associated serine-threonine protein kinase 1 (Rock1) is ectopically expressed in multiple malignant tumors including osteosarcoma. The present study aimed to clarify whether the combined ectopically expressed miR-335 and Rock1 was correlated with clinicopathological features and prognosis in patients with osteosarcoma. The expression of miR-335 and Rock1 in 91 osteosarcoma tissue samples and 47 noncancerous bone tissues were determined respectively by in situ hybridization and immunohistochemistry. The association between miR-335 and Rock1 expression with the clinicopathological features of osteosarcoma was calculated using the Pearson's χ² test. Spearman's correlation analysis was used to study the association between the miR-335 and Rock1 expression. Survival curves were drawn using the Kaplan-Meier method. Univariate and multivariate analysis was performed using the Cox's proportional hazard regression model to allow the prognostic values to be assessed. Expression levels of miR-335 were significantly reduced in osteosarcoma tissues (P<0.001), compared with that in noncancerous bone tissues, while Rock1 expression was significantly increased in osteosarcoma tissues (P<0.001). A strong correlation between miR-335 and Rock1 expression was also shown (P<0.001). Decreased miR-335 expression was identified to be positively associated with higher clinical stage (P=0.004) and distant metastasis (P=0.016), while elevated expression levels of Rock1 was positively associated with a larger tumor size (P=0.013), higher clinical stage (P=0.027) and distant metastasis (P=0.022). The combined high expression of Rock1 and low expression of miR-335 was clearly associated with distant metastasis (P=0.010) and a higher clinical stage (P=0.010). Patients with elevated Rock1 or decreased miR-335 expression exhibited a worse overall survival (OS) and disease-free survival (DFS) compared with patients with decreased Rock1 or increased miR-335 (P<0.001 for the two). In addition, patients with decreased miR-335 and increased Rock1 had the worst OS and DFS (P<0.001 for the two). In multivariate survival analysis, clinical stage (P=0.002 for DFS, P=0.015 for OS), distant metastasis (P=0.024 for DFS, P=0.002 for OS), low expression of miR-335 (P<0.001 for DFS, P=0.002 for OS) and combined depressed miR-335 and elevated Rock1 (P=0.021 for DFS, P=0.050 for OS) expression remained as the independent prognostic factors for DFS and OS. The present findings suggest that there may be an association between the combined downregulation of miR-335 and upregulation of Rock1 with tumor progression and adverse prognosis in patients with osteosarcoma.

MicroRNA-148a Acts as a Tumor Suppressor in Osteosarcoma via Targeting Rho-Associated Coiled-Coil Kinase

MicroRNAs (miRs) have been demonstrated to be involved in the development and progression of osteosarcoma (OS), but the molecular mechanism still remains to be fully investigated. The present study investigated the function of miR-148a in OS, as well as its underlying mechanism. Our data showed that miR-148a was significantly downregulated in OS tissues compared to their matched adjacent normal tissues, and also in OS cell lines compared to normal human osteoblast cells. Low expression of miR-148a was significantly associated with tumor progression and a poor prognosis for OS patients. Rho-associated coiled-coil kinase 1 (ROCK1) was then identified as a target of miR-148a in Saos-2 and U2OS cells, and the expression of ROCK1 was significantly increased in OS tissues and cell lines. Moreover, the protein expression of ROCK1 was markedly reduced in miR-148a-overexpressing Saos-2 and U2OS cells, but significantly increased in miR-148a-downregulated Saos-2 and U2OS cells. Further investigation indicated that miR-148a had a suppressive effect on the proliferative, migratory, and invasive capacities of Saos-2 and U2OS cells. Moreover, overexpression of ROCK1 attenuated the inhibitory effects of miR-148a upregulation on the malignant phenotypes of Saos-2 and U2OS cells. In addition, overexpression of miR-148a significantly inhibited the tumor growth of U2OS cells in nude mice. Taken together, these data demonstrate that miR-148a acts as a tumor suppressor in OS, at least partly, via targeting ROCK1. Therefore, the miR-148a/ROCK1 axis may become a potential therapeutic target for OS.

Targeting ROCK2 rather than ROCK1 inhibits Ewing sarcoma malignancy

Understanding the molecular processes characterizing Ewing sarcoma (EWS) cell migration is crucial to highlight novel therapies for patients with disseminated disease. In this study we analyzed the role of ROCK kinases in the regulation of cell migration, growth and differentiation of EWS cells. Overexpression of ROCK promotes invasion and metastasis in many solid tumors. However, the effect of ROCK in EWS has not been extensively investigated. Expression of ROCK1 and ROCK2 was analyzed by western blotting in a representative panel of human EWS cell lines, in comparison with the parameters of in vitro malignancy. We investigated the effects of a ROCK2 specific inhibitor toward those of a pan-ROCK inhibitor on the growth, migration and differentiation of two EWS cell lines. ROCK2 but not ROCK1 expression was found to be associated with in vitro cell migration and anchorage-independent growth capabilities. Exposure of EWS cells to ROCK inhibitors significantly reduced migration and growth, while favoring morphology changes and neural differentiation. These effects were more striking when cells were specifically deprived of ROCK2 activity. Our findings lead to consider ROCK2, rather than ROCK1, as a possible molecular target for the treatment of EWS.

Upregulation of ROCK2 in gastric cancer cell promotes tumor cell proliferation, metastasis and invasion

Rho-associated coiled-coil-containing protein kinase 2 (ROCK2) has been known as an effector for the small GTPase Rho and plays an important role in tumor progression and metastasis. However, the effect of ROCK2 in gastric cancer (GC) has not been identified. This study showed that ROCK2 expression significantly increased in clinical GC tissues compared with adjacent non-cancer tissues. Immunohistochemistrical analysis showed that high expression of ROCK2 was correlated with tumor grade, tumor-node-metastasis stage, infiltration depth, lymph node invasion and Ki-67, and predicted poor prognosis in 135 gastric cancer specimens. In addition, we found that upregulated ROCK2 promoted proliferation, metastasis and invasion of GC cells, while ROCK2 knockdown led to the opposite results in vitro by Cell Counting Kit-8 (CCK-8) assay, colony formation assays, flow cytometric analysis and trans-well assays. Our findings supported that ROCK2 was a significant protein in the progress of GC and would provide a novel promising therapeutic strategy against human GC.

Rho-associated kinase 1 inhibition is synthetically lethal with von Hippel-Lindau deficiency in clear cell renal cell carcinoma

Clear Cell Renal Cell Carcinoma (CC-RCC) is the most lethal of all genitourinary cancers. The functional loss of the von Hippel-Lindau (VHL) gene occurs in 90% of CC-RCC, driving cancer progression. The objective of this study was to identify chemical compounds that are synthetically lethal with VHL deficiency in CC-RCC. An annotated chemical library, the Library of Pharmacologically Active Compounds (LOPAC), was screened in parallel on VHL-deficient RCC4 cells and RCC4VHL cells with re-introduced VHL cDNA. The ROCK inhibitor, Y-27632, was identified and validated for selective targeting of VHL-deficient CC-RCC in multiple genetic backgrounds by clonogenic assays. Downregulation of ROCK1 by siRNA selectively reduced the colony forming ability of VHL-deficient CC-RCC, thus mimicking the effect of Y-27632 treatment, whereas downregulation of ROCK2 had no effect. In addition, two other ROCK inhibitors, RKI 1447 and GSK 429286, selectively targeted VHL-deficient CC-RCC. CC-RCC treatment with ROCK inhibitors is cytotoxic and cytostatic based on BrdU assay, Propidium Iodide (PI) staining, and growth curves; and blocks cell migration based on transwell assay. Importantly, knockdown of Hypoxia Inducible Factor (HIF) β in the VHL-deficient CC-RCC had a protective effect against Y-27632 treatment, mimicking VHL reintroduction. On the other hand, CC-RCCVHL cells were sensitized to Y-27632 treatment in hypoxia (2% O₂). These results suggest that synthetic lethality between ROCK inhibition and VHL deficiency is dependent on HIF activation. Moreover, HIF1α or HIF2α overexpression in CC-RCCVHL cells is sufficient to sensitize them to ROCK inhibition. Finally, Y-27632 treatment inhibited growth of subcutaneous 786-OT1 CC-RCC tumors in mice. Thus, ROCK inhibitors represent potential therapeutics for VHL-deficient CC-RCC.

Triggering of apoptosis in osteosarcoma cells by graphene/single-walled carbon nanotube hybrids via the ROS-mediated mitochondrial pathway

Carbon nanomaterials are increasingly significant in the biological and medical fields, especially becoming promising candidates in treating difficult and complicated disease. Graphene/single-walled carbon nanotubes (G/SWCNT) hybrids is 3D structure which has been constructed by combining 1D single-walled carbon nanotubes (SWCNTs) and 2D graphene. However, the effects of the nanomaterial on biological systems are limited. In this study, we report a systematic investigation of the cytotoxicity and in vivo biodistribution of G/SWCNT hybrids on osteosarcoma cells (HOS and U2OS). The CCK-8, neutral red, and lactic dehydrogenase assays demonstrated that the cytotoxicity of G/SWCNT hybrids exhibits a dose-dependent behavior on osteosarcoma cells. In our conditions, the hybrids were less cytotoxic than graphene and single-walled carbon nanotubes. The results also showed the apoptosis of osteosarcoma cells induced by G/SWCNT hybrids was through the increase of intracellular reactive oxygen species, the decrease of mitochondrial membrane potential, the alternation of apoptosis-related proteins, and then triggered the ROS-mediated mitochondrial pathway. Moreover, the in vivo biodistribution of G/SWCNT hybrids was observed by histological analysis of major organs in mice, and showed that organs were neither damaged nor inflammatory. This study demonstrated that G/SWCNT hybrids could serve as a potential platform in anticancer therapy. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 443-453, 2017.

MicroRNA-199a-5p inhibits cisplatin-induced drug resistance via inhibition of autophagy in osteosarcoma cells

Osteosarcoma (OS) is the most common cancer of the bone. Chemotherapy is commonly used for the clinical treatment of OS. However, chemoresistance to cisplatin [also known as diamminedichloridoplatinum (II) (DDP)] is a major obstacle for OS therapy, the underlying mechanism of which is not fully understood. The present study aimed to investigate the role of microRNA (miR)-199a-5p in the regulation of chemoresistance to DDP in OS cells. Reverse transcription-quantitative polymerase chain reaction demonstrated that the expression level of miR-199a-5p was significantly reduced in human OS MG63 cells. In addition, DDP treatment also upregulated the protein levels of light chain 3 (LC3)-II and Beclin1 as well as the ratio of LC3-II vs. LC3-I in MG63 cells, indicating that autophagy was activated. Restoration of miR-199a-5p expression promoted DDP-induced inhibition of MG63 cell proliferation and inhibited DDP-induced autophagy, as indicated by the reduced protein levels of LC3-II and Beclin1 and the ratio of LC3-II vs. LC3-I. Finally, luciferase reporter assay data revealed that miR-199a-5p directly targeted Beclin1 and negatively mediated Beclin1 expression at a post-transcriptional level in MG63 cells. In conclusion, our study suggests that miR-199a-5p promotes the cytotoxicity of DDP in OS cells via inhibition of autophagy. Therefore, miR-199a-5p/autophagy signaling is involved in chemoresistance and may become a potential target for the treatment of DDP-resistant OS.

Investigation of Rho-Kinase Expressions and Polymorphisms in Mantle Cell Lymphoma Patients

OBJECTIVE

Mantle cell lymphoma (MCL) is a rare but aggressive form of B-cell non-Hodgkin lymphoma characterized by excessive expression of cyclin D1. Intracellular signaling enzyme Rho-kinase (ROCK) can contribute to cellular migration, proliferation, and differentiation, as well as tumor development and metastasis. However, ROCK gene and protein expressions or polymorphisms have never been investigated in MCL patients. The purpose of this study was to investigate the role of ROCK gene and protein expressions in MCL patients. We also examined ROCK2 gene polymorphisms in this study.

MATERIALS AND METHODS

A total of 60 patients with MCL and 60 healthy controls were included in this retrospective study. Hematoxylin and eosin-stained lymph node tissue slides in the entire archive were reevaluated and used for immunohistochemistry, gene expression, and polymerase chain reaction studies.

RESULTS

In immunohistochemical studies, there were significant increases in ROCK1 (p=0.0009) and ROCK2 (p<0.0001) protein expressions in MCL patients when compared with the control group. Although a marked increase in ROCK1 gene expression (p=0.0215) was noted, no significant change was observed in ROCK2 gene expression in MCL patients. Seven ROCK2 polymorphisms were studied, but the results showed no significant differences between the groups.

CONCLUSION

This is the first study to show that ROCK1 gene and ROCK protein expressions may contribute to the development of MCL.

Long noncoding RNA MALAT1 as a potential therapeutic target in osteosarcoma

Recent studies have revealed that long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) plays an important role in the development of several solid tumors. However, the function of MALAT1 in the tumorigenesis of osteosarcoma remains unknown. In the present study, levels of MALAT1 in human osteosarcoma cell lines and tissues were detected by quantitative real-time polymerase chain reaction (RT-PCR). The roles of MALAT1 in osteosarcoma were investigated by using in vitro and in vivo assays. We observed that MALAT1 expression was up-regulated in human osteosarcoma cell lines and tissues. In vitro knockdown of MALAT1 by siRNA significantly inhibited cell proliferation and migration, and induced cell cycle arrest and apoptosis in osteosarcoma cells. In addition, MALAT1 knockdown markedly suppressed the formation of tubular network structures and caused breakage of stress fibers in osteosarcoma cell lines U2OS and MNNG/HOS. Furthermore, MALAT1 knockdown delayed tumor growth in an osteosarcoma xenograft model. Specifically, we found that administration of MALAT1 siRNA decreased the protein levels of RhoA and its downstream effectors Rho-associated coiled-coil containing protein kinases (ROCKs). Taken together, these findings suggest that MALAT1 plays an oncogenic role in osteosarcoma and may be a promising therapeutic target for the treatment of osteosarcoma patients. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:932-941, 2016.

Rho Kinases in Health and Disease: From Basic Science to Translational Research

Rho-associated kinases ROCK1 and ROCK2 are key regulators of actin cytoskeleton dynamics downstream of Rho GTPases that participate in the control of important physiologic functions, S including cell contraction, migration, proliferation, adhesion, and inflammation. Several excellent review articles dealing with ROCK function and regulation have been published over the past few years. Although a brief overview of general molecular, biochemical, and functional properties of ROCKs is included, an effort has been made to produce an original work by collecting and synthesizing recent studies aimed at translating basic discoveries from cell and experimental models into knowledge of human physiology, pathophysiological mechanisms, and medical therapeutics. This review points out the specificity and distinct roles of ROCK1 and ROCK2 isoforms highlighted in the last few years. Results obtained from genetically modified mice and genetic analysis in humans are discussed. This review also addresses the involvement of ROCKs in human diseases and the potential use of ROCK activity as a biomarker or a pharmacological target for specific inhibitors.

MicroRNA-126 inhibits tumor cell invasion and metastasis by downregulating ROCK1 in renal cell carcinoma

MicroRNAs (miRNAs) are involved in cancer development and progression. Renal cell carcinoma (RCC) frequently undergoes metastasis and has a high mortality rate. The current study measured miRNA-126 (miR-126) expression levels in 128 pairs of clear cell RCC and adjacent normal kidney tissue samples by reverse transcription-quantitative polymerase chain reaction, and analyzed the association between miR-126 and various clinicopathological parameters. In addition, cell proliferation, wound healing and cell invasion assays were conducted using RCC cells overexpressing miR-126. Potential miR-126 target genes and the signaling pathways that may be regulated by miR-126 were then examined. miR-126 expression was significantly reduced in patients with metastatic RCC compared with patients without metastasis. Consistently, overexpression of miR-126 in RCC cells significantly inhibited cell proliferation, migration and invasion in vitro compared with negative control miRNA. A luciferase reporter assay demonstrated that miR-126 targets Rho associated coiled-coil containing protein kinase 1 (ROCK1) by directly binding the 3′-untranslated region. Furthermore, western blotting identified miR-126 as an important regulator of the AKT and extracellular signal-regulated 1/2 signaling pathways. The results of the present study indicate that miR-126 inhibits RCC cell proliferation, migration and invasion by downregulating ROCK1. These findings suggest that miR-126 may be valuable as a potential target for therapeutic intervention in RCC.

MicroRNA-144 suppresses osteosarcoma growth and metastasis by targeting ROCK1 and ROCK2

Osteosarcoma (OS) is the most common primary tumor of bone. MicroRNAs (miRNAs) are a class of endogenously expressed small non-coding RNAs that are strongly implicated in cancerous processes. However, our current understanding of the biological role of miRNAs in OS remains incomplete. In the present study, miR-144 was markedly downregulated in OS cell lines and clinical specimens. Low-level expression of miR-144 was significantly associated with distant metastasis and poor prognosis. Functional studies demonstrated that ectopic expression of miR-144 suppresses tumor cell proliferation and metastasis in vitro as well as in vivo. Furthermore, we identified Rho-associated kinases 1 and 2 (ROCK1 and ROCK2) as direct targets for miR-144 binding, resulting in suppression of their expression. Exogenous expression of ROCK1 or ROCK2 in 143B-miR-144 cells partially restored miR-144-inhibited cell proliferation and invasion. In clinical OS specimens, ROCK1 and ROCK2 levels were elevated, relative to that in paired normal bone tissues, and inversely correlated with miR-144 expression. Taken together, miR-144 suppresses OS progression by directly downregulating ROCK1 and ROCK2 expression, and may be a promising therapeutic target for OS.

MicroRNA-198 inhibited tumorous behaviors of human osteosarcoma through directly targeting ROCK1

Osteosarcoma is an aggressive primary sarcoma of bone and occurs mainly in adolescents and young adults. The prognosis of OS remains poor, and most of them will die due to local relapse or metastases. The discovery of microRNAs provides a new possibility for the early diagnosis and treatment of OS. Thus, the aim of this study was to explore the expression and functions of microRNA-198 (miR-198) in osteosarcoma. The expression levels of miR-198 were determined by qRT-PCR in osteosarcoma tissues and cell lines. Cell proliferation assays, migration and invasion assays were adopted to investigate the effects of miR-198 on tumorous behaviors of osteosarcoma cells. The results showed that miR-198 expression levels were lower in osteosarcoma tissues and cell lines. In addition, low miR-198 expression levels were correlated with TNM stage and distant metastasis. After miR-198 mimics transfection, cell proliferation, migration and invasion were significantly suppressed in the osteosarcoma cells. Furthermore, ROCK1 was identified as a novel direct target of miR-198 in osteosarcoma. These findings suggested that miR-198 may act not only as a novel prognostic marker, but also as a potential target for molecular therapy of osteosarcoma.

Immunohistochemical evaluation of ROCK activation in invasive breast cancer

BACKGROUND

Two isoforms of Rho-associated coiled-coil kinase (ROCK), ROCKI and ROCKII, play an important role in many cellular processes. Despite the accumulating evidence showing that ROCK could be a potential cancer therapeutic target, the relevant tumor types to ROCK activation are not well clarified. The aim of this study was to evaluate the ROCK activation status in different tumor types of breast cancer.

RESULTS

We evaluated the immunoreactivities of phosphorylation-specific antibodies of ROCKI and ROCKII to inform their kinase activation in 275 of breast carcinoma tissues, including 56 of carcinoma in situ, 116 of invasive carcinoma, and 103 of invasive carcinoma with metastasis. ROCKII activation signal detected in nucleus was significantly correlated with tumor metastasis, while ROCKI and cytosolic ROCKII activation signals made no significant difference in that metastasis. Furthermore, nuclear ROCKII activation signal was associated with poor clinical outcome and correlated with late tumor stage, low expression of estrogen receptor (ER) and progesterone receptor (PR), overexpression of human epidermal growth factor receptor 2 (HER2) and high Ki67 labeling index.

CONCLUSIONS

Nuclear ROCKII activation signal might contribute to the tumor metastasis in breast cancer. Differences in ROCK activation that underlie the phenotypes of breast cancer could enhance our understanding for the use of ROCK inhibitors in cancer therapy.

Possible Gender-Related Modulation by the ROCK1 Gene in Colorectal Cancer Susceptibility

AIM

In view of accumulating evidence supporting a pivotal role of the Rho/ROCK pathway in cancer, we investigated Rho-kinase polymorphisms as potential susceptibility factors in colorectal cancer (CRC) in a representative sample of the Italian population.

METHODS

DNA obtained from the peripheral blood samples of 137 CRC patients and 141 healthy controls was genotyped for four ROCK1 (rs35996865; rs73963110; rs2127958; rs288980) and five ROCK2 (rs12692437; rs7563468; rs35768389; rs17463896; rs16857265) selected single nucleotide polymorphisms.

RESULTS

None of the allelic variants of the nine selected markers was associated with the occurrence of CRC or with the development of regional lymph node metastasis. By contrast, the ROCK1 rs35996865 G variant allele was significantly more frequent in male patients (p = 0.028) than in the control group.

CONCLUSION

This finding is, at present, the first that points to a possible gender-related modulation by the ROCK1 gene in CRC susceptibility.

MicroRNA‑144 inhibits migration and proliferation in rectal cancer by downregulating ROCK‑1

Cancer of the colon and rectum are two distinct entities, which require different treatment strategies and separate treatment. MicroRNAs (miRNAs) act as critical regulators of genes involved in several biological processes. Aberrant alterations of miRNAs have been found in several types of cancer, including colon cancer and rectal cancer. Extensive catalogues of downregulated miRNAs have been identified for colon cancer, whereas only limited data are available for rectal cancer. An example of miRNA profiling in a previous study found that miRNA (miR)‑144 showed aberrant expression and appeared to be rectal cancer‑specific, its expression not being reported in colon cancer. In the present study, the role of miR‑144 in rectal cancer was investigated. SW837 and SW1463 cell lines were selected as rectal cell carcinoma cells. Using reverse transcription-quantitative polymerase chain reaction, western blot, BrdU, cell migration and cell viability assays, it was found that the expression levels of miR‑144 were significantly reduced in the SW837 and SW1463 cell lines, and the overexpression of miR‑144 suppressed rectal cancer cell viability, migration and proliferation. In addition, Rho‑associated coiled‑coil containing protein kinase 1 (ROCK1) was identified as a target of miR‑144 in the rectal cancer cells. The supplementation of ROCK1 markedly restored the cell migration and proliferation, which was inhibited by miR‑144. Together, the data of the present study demonstrated that miR‑144 acts as a tumor suppressor by targeting ROCK1, and indicates the potential of miR‑144 as a novel biomarker and target in the treatment of rectal cancer.

miR-584 Suppresses Invasion and Cell Migration of Thyroid Carcinoma by Regulating the Target Oncogene ROCK1

BACKGROUND

Uncovering the target gene of miR-584 to control thyroid carcinoma (TC) invasion and migration is of central importance in the diagnosis, treatment, and prognosis of TC. To validate whether miR-584 has a tumor-suppressive role in thyroid cancer cells by targeting ROCK1, a series of experiments were conducted to figure out the mechanism of action of miR-584.

MATERIAL AND METHODS

Migration analyses and cell proliferation assays were performed using miR-584-transfected cells. The expression levels of miR-584 in TC were detected by using real-time polymerase chain reaction (PCR). Western blot analyses were conducted to find out the relationship between the tumor suppressor miR-584 and the target oncogene ROCK1 protein expression levels. Wound healing experiments were used to examine the relationships between miR-584 and the migration of thyroid cancer K1 cells and the effects of ROCK1 knockdown on K1 cell motility.

RESULTS

Our results demonstrate that altering the miR-584 levels affects human thyroid cancer cell migration, but has no effect on cell proliferation. The relative ROCK-1 expression levels were 1 and 0.54 in the scrambled-sequence control group and the miR-584 group, respectively. K1 cells transfected with siRNA-ROCK-1 showed weaker cell migration than cells transfected with siRNA-NC (negative control); the cell motility ratios were 18% and 27%, respectively.

CONCLUSION

These results indicate that miR-584 could inhibit the expression of ROCK1, and ROCK1 knockdown would further affect the migration ability of K1 cells.

MicroRNA-144 acts as a tumor suppressor by targeting Rho-associated coiled-coil containing protein kinase 1 in osteosarcoma cells

MicroRNAs (miRs) have been demonstrated to be associated with multiple processes in the development and progression of human malignancies. Previous studies have observed aberrant downregulation of miR‑144 in several types of cancer, including osteosarcoma. However, the function of miR‑144 and the underlying mechanism in osteosarcoma remain to be elucidated. The present study indicated that miR‑144 was markedly downregulated in osteosarcoma tissues and cell lines compared with that in the normal controls. Restoration of miR‑144 significantly inhibited cell proliferation, migration and invasion of MG‑63 osteosarcoma cells. In addition, Rho‑associated coiled‑coil containing protein kinase 1 (ROCK1) was identified as a novel target of miR‑144 in MG‑63 osteosarcoma cells. Furthermore, knockdown of ROCK1 suppressed the proliferation, migration and invasion of MG‑63 osteosarcoma cells to a similar extent to the effects of miR‑144 overexpression. In addition, the mRNA expression of ROCK1 was increased in osteosarcoma tissues and was negatively correlated with the expression of miR‑144. In conclusion, the results of the present study suggested that miR‑144 acts as a tumor suppressor by targeting ROCK1 in osteosarcoma.