RhoA/ROCK/PTEN signaling is involved in AT-101-mediated apoptosis in human leukemia cells in vitro and in vivo

Inactivation of KDM5A suppresses growth and enhances chemosensitivity in liver cancer by modulating ROCK1/PTEN/AKT pathway

Liver cancer is a kind of malignant tumor with poor sensitivity to chemotherapy. It is urgent to investigate approaches to improve the outcome of chemotherapy. KDM5A has been reported to be an oncogene in various cancers and is associated with drug resistance. However, the functions of KDM5A in chemotherapeutic sensitivity of liver cancer not been well illustrated. In this study, we found that KDM5A was upregulated in liver cancer tissue and cell lines. KDM5A knockdown using a gene interference strategy suppressed the growth of liver cancer in vitro and in vivo. CPI-455, a pharmacological inactivation of KDM5A enhanced the cytotoxicity of cisplatin (CDDP) in liver cells. CPI-455 and CDDP cotreatment resulted in apoptosis and mitochondrial dysfunction. We also found that knockdown or inactivation of KDM5A resulted in the downregulation of ROCK1, an oncogene regulating the activation of the PTEN/AKT signaling pathway. In particular, overexpression of ROCK1 or SF1670, a pharmacological inhibitor of PTEN, alleviated the cytotoxicity of CPI-455 and CDDP cotreatment. In HCCLM3 xenografts, CPI-455 and CDDP cotreatment dramatically inhibited the growth of xenograft tumor compared to CPI-455 or CDDP treatment alone. In conclusion, this study suggested that targeting the inactivation of KDM5A is an efficient strategy to enhance the chemosensitivity of liver cancer cells to CDDP by modulating the ROCK1/PTEN/AKT signaling pathway.

Novel Dual AChE and ROCK2 Inhibitor Induces Neurogenesis via PTEN/AKT Pathway in Alzheimer's Disease Model

Alzheimer's disease (AD) is a progressive and complex neurodegenerative disease. Acetylcholinesterase inhibitors (AChEIs) are a major class of drugs used in AD therapy. ROCK2, another promising target for AD, has been associated with the induction of neurogenesis via PTEN/AKT. This study aimed to characterize the therapeutic potential of a novel donepezil-tacrine hybrid compound (TA8Amino) to inhibit AChE and ROCK2 protein, leading to the induction of neurogenesis in SH-SY5Y cells. Experiments were carried out with undifferentiated and neuron-differentiated SH-SY5Y cells submitted to treatments with AChEIs (TA8Amino, donepezil, and tacrine) for 24 h or 7 days. TA8Amino was capable of inhibiting AChE at non-cytotoxic concentrations after 24 h. Following neuronal differentiation for 7 days, TA8Amino and donepezil increased the percentage of neurodifferentiated cells and the length of neurites, as confirmed by β-III-tubulin and MAP2 protein expression. TA8Amino was found to participate in the activation of PTEN/AKT signaling. In silico analysis showed that TA8Amino can stably bind to the active site of ROCK2, and in vitro experiments in SH-SY5Y cells demonstrate that TA8Amino significantly reduced the expression of ROCK2 protein, contrasting with donepezil and tacrine. Therefore, these results provide important information on the mechanism underlying the action of TA8Amino with regard to multi-target activities.

MYO1B enhances colorectal cancer metastasis by promoting the F-actin rearrangement and focal adhesion assembly via RhoA/ROCK/FAK signaling

Background

Colorectal cancer (CRC) has a high worldwide incidence and mortality. Tumor metastasis is one of the primary reasons for the poor prognosis of CRC patients. However, the mechanism underlying CRC metastasis is still unclear. Myosin 1B (MYO1B) is important for cell migration and motility and is part of the myosin superfamily that contains various myosins. Studies of prostate, cervical, and head and neck cancer have revealed preliminary findings concerning the effect of MYO1B on tumor metastasis. However, the role of MYO1B in CRC metastasis, as well as its underlying mechanism, remains unknown.

Methods

Quantitative real-time PCR and immunohistochemical staining methods were used to analyze the expression of MYO1B in human CRC and normal mucosa tissues. Lentivirus vector-based MYO1B oligonucleotides and short hairpin RNA (shRNA) were used to examine the functional relevance of MYO1B in CRC cells. Co-immunoprecipitation, western blotting, and immunofluorescence assays were used to investigate the underlying mechanism of MYO1B-mediated cell migration.

Results

The expression of MYO1B was increased in most CRC tissues and was positively associated with a greater risk of tumor metastasis and poor prognosis for patients. MYO1B was significantly associated with the migration and invasion properties of CRC cells in vitro and in vivo. MYO1B promoted F-actin rearrangement through the ROCK2/LIMK/Cofilin axis by enhancing the activation of RhoA. MYO1B also promoted the assembly of focal adhesions by targeting RhoA.

Conclusions

MYO1B plays a vital role in CRC metastasis by promoting the activation of RhoA. MYO1B may not only be a valid biomarker for predicting the risk of metastasis and poor prognosis in CRC but may also be a potential therapeutic target for patients with a high risk of tumor metastasis.

MiR-361-5p/abca1 and MiR-196-5p/arhgef12 Axis Involved in γ-Sitosterol Inducing Dual Anti-Proliferative Effects on Bronchial Epithelial Cells of Chronic Obstructive Pulmonary Disease

Purpose

Chronic obstructive pulmonary disease (COPD), a progressive and irreversible respiratory disease, becomes the third leading cause of death and results in enormous economic burden on healthcare costs and productivity loss worldwide by 2020. Thus, it is urgent to develop effective anti-COPD drugs.

Materials and Methods

In the present study, two published GEO profiles were used to re-analyze and ascertain the relationships between circulating miRNAs and bronchial epithelial cells (BECs) mRNAs in COPD. The microRNA levels of miR-361-5p and miR-196-5p in plasma of COPD patients and healthy volunteers were detected by qRT-PCR. Next, the effects of γ-sitosterol (GS) on the expression of miR-361-5p and miR-196-5p and cell proliferation were investigated in BEC and H292 cell lines. Finally, whether specific miRNA-mRNA pathways involved in the effect of GS on BECs was assayed using Western Blot, real-time PCR and immunofluorescence.

Results

miR-196-5p and miR-361-5p were, respectively, up- and down-regulated in COPD patients compared with healthy controls. Luciferase assays demonstrated that miR-361-5p and miR-196-5p were, respectively, targeting abca1 and arhgef12 3ʹUTR in BEAS-2B cells. GS significantly suppressed miR-196-5p and promoted miR-361-5p levels in BEAS-2B cells and inhibited BECs proliferation in vitro. GS promoted miR-361-5p expression, which inhibited BCAT1 mRNA and protein levels and weaken mTOR-pS6K pathway, resulted in anti-proliferation in BEAS-2B cells. In addition, RhoA was activated by ARHGEF12 due to the inhibitory effect of miR-196-5p on arhgef12-3ʹUTR which was partially abolished by GS suppressing miR-196-5p expression. Activated RhoA further activated ROCK1-PTEN pathway and finally inhibited mTOR pathway, resulting in induced BECs proliferation. The anti-proliferation effect of GS was not observed in H292 cells.

Conclusion

These findings indicate that miR-361-5p/abca1 and miR-196-5p/arhgef12 axis mediated GS inducing dual anti-proliferation effects on BECs.

High Expression of RhoF Predicts Worse Overall Survival: A Potential Therapeutic Target for non-M3 Acute Myeloid Leukemia

Rho GTPases are involved in multiple human malignancies and diverse biological functions. However, the patterns and prognostic significance of the expression of RhoD subfamily in acute myeloid leukemia (AML) remain unknown. Here, we detected the expressions of RhoD subfamily genes in AML on the basis of several published datasets and analyzed the survival of RhoD subfamily across the TCGA profiles and in a GEO series. We found that the expression of RhoF, but not RhoD, increased in AML patients in TCGA and GEO (all P<0.001); the survival analysis of two independent cohorts demonstrated that higher RhoF expression was significantly associated with poorer overall survival (OS) (P<0.001), whereas RhoD expression had no significant effect on OS in patients with AML (P>0.05); the subgroup analysis showed that high RhoF expression was correlated with poor 1-, 3-, and 5-year OS (P<0.05 for all); upregulated RhoF expression had a more significant prognostic value for OS in the younger patients (age<60), the intensive chemotherapy group, and wild-type groups (IDH1, NRAS, and TP53) (P<0.05 for all). Multivariate analysis indicated high RhoF expression as a strongly independent unfavorable prognostic factor for OS in patients without transplantation (P<0.05). Furthermore, a higher RhoF expression was closely associated with an older age, intermediate-/poor-risk cytogenetics and mutations in IDH1, NRAS, and TP53. RhoF expression was negatively correlated with BM blasts (P=0.020) and WBC (P=0.003). These findings suggest that high RhoF expression is associated with worsening OS in AML patients and is a potential therapeutic target for the treatment of AML.

Plant miR171 modulates mTOR pathway in HEK293 cells by targeting GNA12

Plant microRNAs have shown the capacity to regulate mammalian systems. The potential bioactivity of miR171vr, an isoform of the plant miR171, on human embryonic kidney 293 (HEK293) cells was investigated. Bioinformatics simulations revealed that human G protein subunit alpha 12 (GNA12) transcript could represent an excellent target for miR171vr. To confirm this prediction, in vitro experiments were performed using a synthetic microRNA designed on miR171vr sequence. MiR-treated cells showed a significant decrease of GNA12 mRNA and protein levels, confirming the putative cross-kingdom interaction. In addition, miR171vr determined the modulation of GNA12 downstream signaling factors, including mTOR, as expected. Finally, the effect of the plant miRNA on HEK293 cell growth and its stability in presence of several stressors, such as those miming digestive processes and procedures for preparing food, were evaluated. All this preliminary evidence would suggest that miR171vr, introduced by diet or as supplement in gene therapies, could potentially influence human gene expression, especially for treating disorders where GNA12 is over-expressed (i.e. oral cancer, breast and prostate adenocarcinoma) or mTOR kinase is down-regulated (e.g. obesity, type 2 diabetes, neurodegeneration).

The HMGB1-2 Ovarian Cancer Interactome. The Role of HMGB Proteins and Their Interacting Partners MIEN1 and NOP53 in Ovary Cancer and Drug-Response

High mobility group box B (HMGB) proteins are overexpressed in different types of cancers such as epithelial ovarian cancers (EOC). We have determined the first interactome of HMGB1 and HMGB2 in epithelial ovarian cancer (the EOC-HMGB interactome). Libraries from the SKOV-3 cell line and a primary transitional cell carcinoma (TCC) ovarian tumor were tested by the Yeast Two Hybrid (Y2H) approach. The interactome reveals proteins that are related to cancer hallmarks and their expression is altered in EOC. Moreover, some of these proteins have been associated to survival and prognosis of patients. The interaction of MIEN1 and NOP53 with HMGB2 has been validated by co-immunoprecipitation in SKOV-3 and PEO1 cell lines. SKOV-3 cells were treated with different anti-tumoral drugs to evaluate changes in HMGB1, HMGB2, MIEN1 and NOP53 gene expression. Results show that combined treatment of paclitaxel and carboplatin induces a stronger down-regulation of these genes in comparison to individual treatments. Individual treatment with paclitaxel or olaparib up-regulates NOP53, which is expressed at lower levels in EOC than in non-cancerous cells. On the other hand, bevacizumab diminishes the expression of HMGB2 and NOP53. This study also shows that silencing of these genes affects cell-viability after drug exposure. HMGB1 silencing causes loss of response to paclitaxel, whereas silencing of HMGB2 slightly increases sensitivity to olaparib. Silencing of either HMGB1 or HMGB2 increases sensitivity to carboplatin. Lastly, a moderate loss of response to bevacizumab is observed when NOP53 is silenced.

Protective effect of CTRP6 on cerebral ischemia/reperfusion injury by attenuating inflammation, oxidative stress and apoptosis in PC12 cells

The newly identified C1q/tumor necrosis factor (TNF)-related protein-6 (CTRP6) is a highly conserved paralog of adiponectin with modulatory effects on metabolism and inflammation. However, the role of CTRP6 in cerebral ischemia/reperfusion (I/R) injury remains unknown. The aim of the present study was to explore the protective effects of CTRP6 against cerebral I/R injury and elucidate the possible underlying mechanisms. Oxygen-glucose deprivation and reperfusion (OGD/R) was used to induce an I/R injury model in vitro. Western blotting, reverse transcription-quantitative PCR, ELISA and flow cytometry analysis were used to measure the levels of CTRP6 along with those of inflammation-, oxidative stress- and apoptosis-related cytokines. The results indicated that CTRP6 expression was markedly downregulated following OGD/R. OGD/R also increased i) the activities of pro-inflammatory factors TNF-α, interleukin (IL)-1β, IL-6 and the levels of the oxidative products reactive oxygen species and malondialdehyde; ii) the ratio of apoptotic PC12 cells and iii) the expression of the pro-apoptotic proteins Bax, cleaved caspase-3 and cleaved caspase-9. In addition, the activities of the anti-inflammatory factors IL-10 and superoxide dismutase and the expression of the anti-apoptotic protein Bcl-2 were decreased. However, overexpression of CTRP6 rescued OGD/R-stimulated exacerbation of inflammation, oxidative stress and apoptosis. Mechanistically, OGD/R activated Ras homolog family member A (RhoA)/Rho-associated coiled-coil-containing protein kinase (Rock)/phosphatase and tensin homologue deleted on chromosome 10 (PTEN) signaling, whereas CTRP6 overexpression restored the expression of RhoA, Rock, PTEN, phosphoinositide 3-kinase (PI3K) and protein kinase B (Akt). Furthermore, when CTRP6 and RhoA were overexpressed at the same time, RhoA abolished the protective effects of CTRP6 overexpression on OGD/R-induced inflammation, oxidative stress and apoptosis, while the presence of a PTEN inhibitor recovered the protective effects of CTRP6. Taken together, the findings of the present study indicate that CTRP6 attenuates cerebral ischemia/reperfusion-induced inflammation, oxidative stress and apoptosis via inhibiting the RhoA/Rock/PTEN pathway, thereby activating PI3K/Akt signaling.

Effects of Short-Term Inhibition of Rho Kinase on Dromedary Camel Oocyte In Vitro Maturation

Simple Summary

Our results revealed, for the first time, that short-term inhibition of Rho-associated protein kinases (ROCK) for 4 h prior to in vitro maturation (IVM) in a biphasic IVM approach improved oocyte nuclear maturation, producing more MII oocyte, through modulating the expression of cytokinesis- and antiapoptosis-related mRNA transcripts. This positive result suggests ROCK inhibitor as a potential candidate molecule to exploit in the control of oocyte meiotic maturation.

Abstract

This is the first report on a biphasic in vitro maturation (IVM) approach with a meiotic inhibitor to improve dromedary camel IVM. Spontaneous meiotic resumption poses a major setback for in vitro matured oocytes. The overall objective of this study was to improve in vitro maturation of dromedary camel oocytes using ROCK inhibitor (Y-27632) in a biphasic IVM to prevent spontaneous meiotic resumption. In the first experiment, we cultured immature cumulus–oocyte complexes (COCs, n = 375) in a prematuration medium supplemented with ROCK inhibitor (RI) for 2 h, 4 h, 6 h, and 24 h before submission to normal in vitro maturation to complete 28 h. The control was cultured for 28 h in the absence of RI. In the first phase of experiment two, we cultured COCs (n = 480) in the presence or absence (control) of RI for 2 h, 4 h, 6 h, and 24 h, and conducted real-time relative quantitative PCR (qPCR) on selected mRNA transcripts. The same was done in the second phase, but qPCR was done after completion of normal IVM. Assessment of nuclear maturation showed that pre-IVM for 4 h yielded an increase in MII oocyte (54.67% vs. 26.6% of control; p < 0.05). As expected, the same group showed the highest degree (2) of cumulus expansion. In experiment 2, qPCR results showed significantly higher expression of ACTB and BCL2 in the RI group treated for 4 h when compared with the other groups. However, their relative quantification after biphasic IVM did not reveal any significant difference, except for the positive response of BCL2 and BAX/BCL2 ratio after 4 and 6 h biphasic IVM. In conclusion, RI prevents premature oocyte maturation and gave a significantly positive outcome during the 4 h treatment. This finding is a paradigm for future investigation on dromedary camel biphasic IVM and for improving the outcome of IVM in this species.

RhoA as a Key Regulator of Innate and Adaptive Immunity

RhoA is a ubiquitously expressed cytoplasmic protein that belongs to the family of small GTPases. RhoA acts as a molecular switch that is activated in response to binding of chemokines, cytokines, and growth factors, and via mDia and the ROCK signaling cascade regulates the activation of cytoskeletal proteins, and other factors. This review aims to summarize our current knowledge on the role of RhoA as a general key regulator of immune cell differentiation and function. The contribution of RhoA for the primary functions of innate immune cell types, namely neutrophils, macrophages, and conventional dendritic cells (DC) to (i) get activated by pathogen-derived and endogenous danger signals, (ii) migrate to sites of infection and inflammation, and (iii) internalize pathogens has been fairly established. In activated DC, which constitute the most potent antigen-presenting cells of the immune system, RhoA is also important for the presentation of pathogen-derived antigen and the formation of an immunological synapse between DC and antigen-specific T cells as a prerequisite to induce adaptive T cell responses. In T cells and B cells as the effector cells of the adaptive immune system Rho signaling is pivotal for activation and migration. More recently, mutations of Rho and Rho-modulating factors have been identified to predispose for autoimmune diseases and as causative for hematopoietic malignancies.

Hypoxia-induced ARHGAP26 deficiency inhibits the proliferation and migration of human ductus arteriosus smooth muscle cell through activating RhoA-ROCK-PTEN pathway

The Rho family plays crucial roles in O₂ -induced vasoconstriction, cell proliferation, and migration. Rho GTPase-activating protein 26 (ARHGAP26) is a GTPase-activating protein for the small GTPases of the Rho family. Our previous studies have demonstrated that ARHGAP26 expression was significantly downregulated in patent human ductus arteriosus (DA) tissue. However, its role underlying the maintenance of DA patency is unclear. In this study, patent (fetal) and constricted (newborn) mouse DA tissues were harvested to confirm the differences in the levels of expression of ARHGAP26. Human DA smooth muscle cells (DASMCs) were isolated and cultured in vitro and used to test the function of ARHGAP26. The expression of ARHGAP26 was significantly lower in patent (fetal) than constricted (newborn) mouse DA. ARHGAP26-knocked-down human DASMCs showed reduced proliferation and migration, which are both crucial to anatomic closure of DA. Moreover, after culturing under hypoxic conditions, the expression of ARHGAP26 in human DASMCs was significantly lower and hypoxia-induced ARHGAP26 deficiency activated the phosphorylation level of phosphatase and tensin homolog (PTEN) in DASMCs by mediating the activity of RhoA and RhoA-associated kinase 1 (ROCK1). Use of Y27632, an inhibitor of ROCK which further reduces the phospholipid activity of PTEN can reverse the inhibitory effect of PTEN on the proliferation and migration of human DASMCs. This provides insight into the molecular regulation of the RhoA-ROCK-PTEN pathway in DA smooth muscle cells, which may be a suitable therapeutic target or diagnostic biomarker for perinatal DA tone management.

Insights into the pharmaceuticals and mechanisms of neurological orphan diseases: Current Status and future expectations

Several rare or orphan diseases have been characterized that singly affect low numbers of people, but cumulatively reach ∼6%-10% of the population in Europe and in the United States. Human genetics has shown to be broadly effective when evaluating subjacent genetic defects such as orphan genetic diseases, but on the other hand, a modest progress has been achieved toward comprehending the molecular pathologies and designing new therapies. Chemical genetics, placed at the interface of chemistry and genetics, could be employed to understand the molecular mechanisms of subjacent illnesses and for the discovery of new remediation processes. This review debates current progress in chemical genetics, and how a variety of compounds and reaction mechanisms can be used to study and ultimately treat rare genetic diseases. We focus here on a study involving Amyotrophic lateral sclerosis (ALS), Duchenne Muscular Dystrophy (DMD), Spinal muscular atrophy (SMA) and Familial Amyloid Polyneuropathy (FAP), approaching different treatment methods and the reaction mechanisms of several compounds, trying to elucidate new routes capable of assisting in the treatment profile.

The cyclohexene derivative MC-3129 exhibits antileukemic activity via RhoA/ROCK1/PTEN/PI3K/Akt pathway-mediated mitochondrial translocation of cofilin

The effects of MC-3129, a synthetic cyclohexene derivative, on cell viability and apoptosis have been investigated in human leukemia cells. Exposure of leukemia cells to MC-3129 led to the inhibition of cell viability and induction of apoptosis through the dephosphorylation and mitochondrial translocation of cofilin. A mechanistic study revealed that interruption of the RhoA/ROCK1/PTEN/PI3K/Akt signaling pathway plays a crucial role in the MC-3129-mediated dephosphorylation and mitochondrial translocation of cofilin and induction of apoptosis. Our in vivo study also showed that the MC-3129-mediated inhibition of the tumor growth in a mouse leukemia xenograft model is associated with the interruption of ROCK1/PTEN/PI3K/Akt signaling and apoptosis. Molecular docking suggested that MC-3129 might activate the RhoA/ROCK1 pathway by targeting LPAR2. Collectively, these findings suggest a hierarchical model, in which the induction of apoptosis by MC-3129 primarily results from the activation of RhoA/ROCK1/PTEN and inactivation of PI3K/Akt, leading to the dephosphorylation and mitochondrial translocation of cofilin, and culminating in cytochrome c release, caspase activation, and apoptosis. Our study reveals a novel role for RhoA/ROCK1/PTEN/PI3K/Akt signaling in the regulation of mitochondrial translocation of cofilin and apoptosis and suggests MC-3129 as a potential drug for the treatment of human leukemia.

A Boolean network of the crosstalk between IGF and Wnt signaling in aging satellite cells

Aging is a complex biological process, which determines the life span of an organism. Insulin-like growth factor (IGF) and Wnt signaling pathways govern the process of aging. Both pathways share common downstream targets that allow competitive crosstalk between these branches. Of note, a shift from IGF to Wnt signaling has been observed during aging of satellite cells. Biological regulatory networks necessary to recreate aging have not yet been discovered. Here, we established a mathematical in silico model that robustly recapitulates the crosstalk between IGF and Wnt signaling. Strikingly, it predicts critical nodes following a shift from IGF to Wnt signaling. These findings indicate that this shift might cause age-related diseases.

Rho/Rho-associated protein kinase signaling pathway-mediated downregulation of runt-related transcription factor 2 expression promotes the differentiation of dental pulp stem cells into odontoblasts

The present study investigated the role of runt-related transcription factor 2 (Runx2) in regulating the differentiation of human dental pulp stem cells (hDPSCs) into odontoblasts under the mediation of the Rho/Rho-associated protein kinase (ROCK) signaling pathway. hDPSCs and human bone marrow mesenchymal stem cells (hBMSCs) were mineralized to induce differentiation. The expression levels of odontoblast- and osteoblast-specific proteins, dentin sialophosphoprotein (DSPP), osteocalcin (OCN) and Runx2, were measured using western blot analysis. The hDPSCs were treated with Rho/ROCK signaling pathway inhibitor, C3 exoenzyme, and mineralized prior to determining the protein expression levels of RhoA, ROCK, Runx2, OCN, DSPP, and mRNA expression levels of early mineralization genes, including alkaline phosphatase, collagen type I, Msh homeobox 2 and distal-less homeobox 2, and late mineralization genes, including DSPP, dentin matrix protein-1 (DMP-1), bone sialoprotein (BSP) and OCN. Flow cytometry data indicated that 95% of the isolated hDPSCs were positive for mesenchymal stem cell markers, including cluster of differentiation (CD)29, CD90 or CD105, and vascular endothelial cell marker, CD146, whereas <5% of the hDPSCs were positive for hematopoietic stem cell markers, CD34 and CD45. The expression levels of DSPP in hDPSCs and OCN in hBMSCs were significantly upregulated with increased time in mineralization medium (P<0.01), which suggested that hDPSCs and hBMSCs were differentiated into odontoblasts and osteoblasts, respectively. During the osteogenic process, Runx2 protein was highly expressed in mesenchymal stem cells following stimulation with mineralization medium compared with cells that received no stimulation. During odontoblast differentiation in hDPSCs, Runx2 protein was highly expressed in the early stage; however, the expression declined in the late stage. Furthermore, treatment with C3 exoenzyme significantly downregulated the expression of RhoA, ROCK and Runx2 compared with the control in hDPSCs (P<0.01). Additionally, in mineralization solution, C3 exoenzyme also significantly downregulated the expression of Runx2 (P<0.01); however, the Rho/ROCK signaling pathway inhibitor did not significantly impact the expression of early mineralization genes. By contrast, C3 exoenzyme significantly upregulated the expression of DSPP and DMP-1, and downregulated the expression of BSP and OCN (P<0.01). The present findings suggested that odontoblast differentiation in hDPSCs may be regulated by Rho/ROCK signaling pathway-mediated downregulation of Runx2.

Distinct EphB4-mediated mechanisms of apoptotic and resistance to dasatinib in human chronic myeloid leukemia and K562 cell lines

OBJECTIVE

To determine the role and mechanism of EphB4 in dasatinib (DAS) resistance in advanced chronic myeloid leukemia (CML), we explored the EphB4-mediated apoptotic and matrix microenvironment pathway in human CML and K562 cell lines.

METHOD

Heparinized bone marrow samples were obtained from enrolled five patients (identified as A to E and visits identified by number) at initial diagnosis (A1-E1) and in the DAS-resistance advanced phase (A2-E2). Meanwhile, highly DAS-resistant cells, named K562-R cells, were obtained from K562-W cells with increasing concentrations of DAS. Stable under-expressing EphB4 cells (K562-R-EphB4-sh) were obtained from K562-R cells by RNA interference. K562-W, K562-R and K562-R-EphB4-sh cells (10⁸) were respectively injected subcutaneously on the dorsal surface of BALB/C female nude mice to establish the xenografts models.

RESULT

The mRNA/protein of EphB4 was overexpressed in the DAS-resistant A2-E2 in comparison with the A1-E1 human cell lines. Further, compared with K562-R cells, the expressions of EphB4 and p-Rac1/Cdc42 protein/mRNA were significantly downregulated in K562-R-EphB4-sh cells (P<0.01). K562-R cells showed the highest DAS resistance (IC50 10.54±0.67μg/ml), but K562-R-EphB4-sh cells became sensitive to DAS (IC50 1.02±0.1μg/ml, P<0.01). The expression of EphB4/p-RhoA/MCL-1 protein was gradually increased in the stimulating of EphrinB2-Fc, which partly made K562-R-EphB4-sh cells restore sensitivity to DAS (4.18±0.30μg/ml). Meanwhile, the K562-R-EphB4-sh xenografts group had relatively good efficacy compared to K562-R xenografts nude mice receiving the same dose of DAS. The analysis of xenografts tissue also suggested parallel results with the overexpression of EphB4/RhoA/ROCK1/PTEN/MCL-1 in K562-R xenografts, which decreased in the A2-R-EphB4-sh xenografts (P<0.01).

CONCLUSIONS

The present study found that a new DAS resistance pathway of EphB4 overexpression was triggered by EphrinB2-Fc, which induced the resistance to DAS by activating RhoA/ROCK1/PTEN/MCL-1 signaling.

RhoA Proteolysis Regulates the Actin Cytoskeleton in Response to Oxidative Stress

The small GTPase RhoA regulates the actin cytoskeleton to affect multiple cellular processes including endocytosis, migration and adhesion. RhoA activity is tightly regulated through several mechanisms including GDP/GTP cycling, phosphorylation, glycosylation and prenylation. Previous reports have also reported that cleavage of the carboxy-terminus inactivates RhoA. Here, we describe a novel mechanism of RhoA proteolysis that generates a stable amino-terminal RhoA fragment (RhoA-NTF). RhoA-NTF is detectable in healthy cells and tissues and is upregulated following cell stress. Overexpression of either RhoA-NTF or the carboxy-terminal RhoA cleavage fragment (RhoA-CTF) induces the formation of disorganized actin stress fibres. RhoA-CTF also promotes the formation of disorganized actin stress fibres and nuclear actin rods. Both fragments disrupt the organization of actin stress fibres formed by endogenous RhoA. Together, our findings describe a novel RhoA regulatory mechanism.

Anti-cancer effect of ursolic acid activates apoptosis through ROCK/PTEN mediated mitochondrial translocation of cofilin-1 in prostate cancer

Ursolic acid is a type of pentacyclic triterpene compound with multiple pharmacological activities including cancer resistance, protection from liver injury, antisepsis, anti-inflammation and antiviral activity. The present study aimed to investigate the anticancer effect of ursolic acid. Ursolic acid activates cell apoptosis and its pro-apoptotic mechanism remains to be fully elucidated. Cell Counting kit-8 assays, flow cytometric analysis and analysis of caspase-3 and caspase-9 activity were used to estimate the anticancer effect of ursolic acid on DU145 prostate cancer cells. The protein expression of cytochrome c, rho-associated protein kinase (ROCK), phosphatase and tensin homolog (PTEN) and cofilin-1 were examined using western blot analysis. In the present study, ursolic acid significantly suppressed cell growth and induced apoptosis, as well as increasing caspase-3 and caspase-9 activities of DU145 cells. Furthermore, cytoplasmic and mitochondrial cytochrome c protein expression was significantly activated and suppressed, respectively, by ursolic acid. Ursolic acid significantly suppressed the ROCK/PTEN signaling pathway and inhibited cofilin-1 protein expression in DU145 cells. The results of the present study indicate that the anticancer effect of ursolic acid activates cell apoptosis through ROCK/PTEN mediated mitochondrial translocation of cofilin-1 in prostate cancer.

Carnosic Acid-combined Arsenic Trioxide Antileukaemia Cells in the Establishment of NB4/SCID Mouse Model

Despite great improvement in the treatment outcome of APL, treatment failure still sometimes occurs due to the toxicity of arsenic trioxide (ATO). Damage to the heart and liver often occurs even when the dose is lower than the therapeutic dose. Based on the results of cell experiments in vitro in this study, we investigated the synergistic activity of carnosic acid (CA) combined with ATO in the SCID mouse model of human promyelocytic leukaemia in vivo. A NB4/SCID mouse model was established in this study. The NB4/SCID mice were randomly divided into three treatment groups (CA alone, ATO alone and CA combined with ATO) and a control group based on factorial design. The evaluation indicators of the curative effect of the drugs included expressions of cleaved caspase-3, PTEN, p27 gene mRNA and proteins by immunohistochemistry, flow cytometry and Western blot analysis. The survival time was compared between the four groups. The results indicated that verification of the NB4/SCID mouse model was confirmed by histopathological examination. Compared with mice treated by CA or ATO alone, the mice in the combination of CA and ATO group had a higher rate of apoptosis, which was linked with expressions of cleaved caspase-3, PTEN, p27 gene mRNA and proteins. Also, the mice with the longest survival time were those treated with the combination of CA and ATO. In conclusion, the results of the present study indicated that CA and ATO in combination have strong synergistic antileukaemic effects on cell activity.

Molecular Mechanisms of Neurodegeneration in Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease with a high incidence and is the most common genetic cause of infant mortality. SMA is primarily characterized by degeneration of the spinal motor neurons that leads to skeletal muscle atrophy followed by symmetric limb paralysis, respiratory failure, and death. In humans, mutation of the Survival Motor Neuron 1 (SMN1) gene shifts the load of expression of SMN protein to the SMN2 gene that produces low levels of full-length SMN protein because of alternative splicing, which are sufficient for embryonic development and survival but result in SMA. The molecular mechanisms of the (a) regulation of SMN gene expression and (b) degeneration of motor neurons caused by low levels of SMN are unclear. However, some progress has been made in recent years that have provided new insights into understanding of the cellular and molecular basis of SMA pathogenesis. In this review, we have briefly summarized recent advances toward understanding of the molecular mechanisms of regulation of SMN levels and signaling mechanisms that mediate neurodegeneration in SMA.

Novel Insights into the Roles of Rho Kinase in Cancer

Rho-associated coiled-coil kinase (ROCK) is a major downstream effector of the small GTPase RhoA. The ROCK family, consisting of ROCK1 and ROCK2, plays a central role in the organization of the actin cytoskeleton, and is involved in a wide range of fundamental cellular functions such as contraction, adhesion, migration, proliferation, and apoptosis. Since the discovery of effective inhibitors such as fasudil and Y27632, the biological roles of ROCK have been extensively explored in numerous diseases, including cancer. Accumulating evidence supports the concept that ROCK plays important roles in tumor development and progression through regulating many key cellular functions associated with malignancy, including tumorigenicity, tumor growth, metastasis, angiogenesis, tumor cell apoptosis/survival and chemoresistance as well. This review focuses on the new advances of the most recent 5 years from the studies on the roles of ROCK in cancer development and progression; the discussion is mainly focused on the potential value of ROCK inhibitors in cancer therapy.

Bcl-2 family of proteins as drug targets for cancer chemotherapy: the long way of BH3 mimetics from bench to bedside

Bcl-2 proteins are key determinants in the life-death balance. In recent years, proteins in this family have been identified as drug targets in the design of new anti-tumor therapies. Advances in the knowledge of the mechanism of action of anti-apoptotic and pro-apoptotic members of the Bcl-2 family have enabled the development of the so-called 'BH3 mimetics'. These compounds act by inhibiting anti-apoptotic proteins of the family, imitating the function of the BH3-only subset of pro-apoptotic members. Combinations of BH3-mimetics with anti-tumor drugs are being evaluated in both preclinical models and clinical trials. Recent advances in these approaches will be reviewed.

Chatting with the neighbors: crosstalk between Rho-kinase (ROCK) and other signaling pathways for treatment of neurological disorders

ROCK inhibition has been largely applied as a strategy to treat neurodegenerative diseases (NDDs) and promising results have been obtained in the recent years. However, the underlying molecular and cellular mechanisms are not fully understood and different models have been proposed for neurodegenerative disorders. Here, we aim to review the current knowledge obtained for NDDs identifying common mechanisms as well as disease-specific models. In addition to the role of ROCK in different cell types such as neurons and microglia, we focus on the molecular signaling-pathways which mediate the beneficial effects of ROCK. Besides canonical ROCK signaling, modulation of neighboring pathways by non-canonical ROCK-crosstalk is a recurrent pattern in many NDD-model systems and has been suggested to mediate beneficial effects of ROCK-inhibition.

RhoA/mDia-1/profilin-1 signaling targets microvascular endothelial dysfunction in diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is a major cause of blindness in the working-age populations of developed countries, and effective treatments and prevention measures have long been the foci of study. Patients with DR invariably demonstrate impairments of the retinal microvascular endothelium. Many observational and preclinical studies have shown that angiogenesis and apoptosis play crucial roles in the pathogenesis of DR. Increasing evidence suggests that in DR, the small guanosine-5'-triphosphate-binding protein RhoA activates its downstream targets mammalian Diaphanous homolog 1 (mDia-1) and profilin-1, thus affecting important cellular functions, including cell morphology, motility, secretion, proliferation, and gene expression. However, the specific underlying mechanism of disease remains unclear.

CONCLUSION

This review focuses on the RhoA/mDia-1/profilin-1 signaling pathway that specifically triggers endothelial dysfunction in diabetic patients. Recently, RhoA and profilin-1 signaling has attracted a great deal of attention in the context of diabetes-related research. However, the precise molecular mechanism by which the RhoA/mDia-1/profilin-1 pathway is involved in progression of microvascular endothelial dysfunction (MVED) during DR has not been determined. This review briefly describes each feature of the cascade before exploring the most recent findings on how the pathway may trigger endothelial dysfunction in DR. When the underlying mechanisms are understood, novel therapies seeking to restore the endothelial homeostasis comprised in DR will become possible.

Sequential treatment with AT-101 enhances cisplatin chemosensitivity in human non-small cell lung cancer cells through inhibition of apurinic/apyrimidinic endonuclease 1-activated IL-6/STAT3 signaling pathway

AT-101, known as R-(–)-gossypol, is a potent anticancer agent, but its chemosensitizing effects remain elusive. The present study aimed to examine whether AT-101 could increase the sensitivity of non-small cell lung cancer A549 cells to cisplatin (CDDP) and the underlying mechanisms. We evaluated the efficacy of the sequential treatment with AT-101 and CDDP using both in vitro and in vivo models. Our results showed that as compared to AT-101 or CDDP monotherapy, or AT-101 plus CDDP concurrent treatment, the sequential treatment significantly inhibited cell proliferation and migration and induced tumor cell death. Moreover, the efficacy of the sequential treatment was also confirmed in a mouse A549 xenograft model. Our study revealed that AT-101 inhibited the reduced status of apurinic/apyrimidinic endonuclease 1 (APE1) and attenuated APE1-mediated IL-6/STAT3 signaling activation by decreasing IL-6 protein expression; suppressing the STAT3–DNA binding; and reducing the expression of the downstream antiapoptotic proteins Bcl-2 and Bcl-xL. In conclusion, AT-101 enhances the sensitivity of A549 cells to CDDP in vitro and in vivo through the inhibition of APE1-mediated IL-6/STAT3 signaling activation, providing a rationale for the combined use of AT-101 and CDDP in non-small cell lung cancer chemotherapy.

ROCK1 as a novel prognostic marker in vulvar cancer

Background

Vulvar carcinoma is an infrequent tumour, accounting for fewer than 3% of all malignant tumours that affect women, but its incidence is rising in the past few decades. In young women, the manifestation of the vulvar carcinoma is often linked to risk factors such as smoking and HPV infection, but most cases develop in women aged over 50 years through poorly understood genetic mechanisms. Rho-associated coiled-coil-containing protein kinase 1 (ROCK1) has been implicated in many cellular processes, but its function in vulvar cancer has never been examined. In this study, we aimed to determine the prognostic value of ROCK1 gene and protein analysis in vulvar squamous cell carcinoma (VSCC).

Methods

ROCK1 expression levels were measured in 16 vulvar tumour samples and adjacent normal tissue by qRT-PCR. Further, 96 VSCC samples were examined by immunohistochemistry (IHC) to confirm the involvement of ROCK1 in the disease. The molecular and pathological results were correlated with the clinical data of the patients. Sixteen fresh VSCC samples were analyzed by array-based comparative genomic hybridization (aCGH).

Results

In each pair of samples, ROCK1 levels were higher by qRT-PCR in normal tissue compared with the tumour samples (p = 0.016). By IHC, 100% of invasive front areas of the tumour and 95.8% of central tumour areas were positive for ROCK1. Greater expression of ROCK1 was associated with the absence of lymph node metastasis (p = 0.022) and a lower depth of invasion (p = 0.002). In addition, higher ROCK1 levels correlated with greater recurrence-free survival (p = 0.001). Loss of ROCK1 was independently linked to worse cancer-specific survival (p = 0.0054) by multivariate analysis. This finding was validated by IHC, which demonstrated enhanced protein expression in normal versus tumour tissue (p < 0.001). By aCGH, 42.9% of samples showed a gain in copy number of the ROCK1 gene.

Conclusions

ROCK1 is lower expressed in tumour tissue when compared with adjacent normal vulvar epithelia. In an independent sample set of VSCCs, lower expression levels of ROCK1 correlated with worse survival rates and a poor prognosis. These findings provide important information for the clinical management of vulvar cancer.