The actin depolymerizing factor (ADF)/cofilin signaling pathway and DNA damage responses in cancer

Sulfamoylated Estradiol Analogs Targeting the Actin and Microtubule Cytoskeletons Demonstrate Anti-Cancer Properties In Vitro and In Ovo

The microtubule-disrupting agent 2-methoxyestradiol (2-ME) displays anti-tumor and anti-angiogenic properties, but its clinical development is halted due to poor pharmacokinetics. We therefore designed two 2-ME analogs in silico-an ESE-15-one and an ESE-16 one-with improved pharmacological properties. We investigated the effects of these compounds on the cytoskeleton in vitro, and their anti-angiogenic and anti-metastatic properties in ovo. Time-lapse fluorescent microscopy revealed that sub-lethal doses of the compounds disrupted microtubule dynamics. Phalloidin fluorescent staining of treated cervical (HeLa), metastatic breast (MDA-MB-231) cancer, and human umbilical vein endothelial cells (HUVECs) displayed thickened, stabilized actin stress fibers after 2 h, which rearranged into a peripheral radial pattern by 24 h. Cofilin phosphorylation and phosphorylated ezrin/radixin/moesin complexes appeared to regulate this actin response. These signaling pathways overlap with anti-angiogenic, extra-cellular communication and adhesion pathways. Sub-lethal concentrations of the compounds retarded both cellular migration and invasion. Anti-angiogenic and extra-cellular matrix signaling was evident with TIMP2 and P-VEGF receptor-2 upregulation. ESE-15-one and ESE-16 exhibited anti-tumor and anti-metastatic properties in vivo, using the chick chorioallantoic membrane assay. In conclusion, the sulfamoylated 2-ME analogs displayed promising anti-tumor, anti-metastatic, and anti-angiogenic properties. Future studies will assess the compounds for myeloproliferative effects, as seen in clinical applications of other drugs in this class.

A glimpse into cofilin-1 role in cancer therapy: A potential target to improve clinical outcomes?

Cofilin-1 (CFL1) modulates dynamic actin networks by severing and enhancing depolymerization. The upregulation of cofilin-1 expression in several cancer types is associated with tumor progression and metastasis. However, recent discoveries indicated relevant cofilin-1 functions under oxidative stress conditions, interplaying with mitochondrial dynamics, and apoptosis networks. In this scenario, these emerging roles might impact the response to clinical therapy and could be used to enhance treatment efficacy. Here, we highlight new perspectives of cofilin-1 in the therapy resistance context and discussed how cofilin-1 is involved in these events, exploring aspects of its contribution to therapeutic resistance. We also provide an analysis of CFL1 expression in several tumors predicting survival. Therefore, understanding how exactly coflin-1 plays, particularly in therapy resistance, may pave the way to the development of treatment strategies and improvement of patient survival.

PLEK2 mediates metastasis and invasion via α5-nAChR activation in nicotine-induced lung adenocarcinoma

Evidence has shown a strong relationship between smoking and epithelial mesenchymal transition (EMT). α5-nicotinic acetylcholine receptor (α5-nAChR) contributes to nicotine-induced lung cancer cell EMT. The cytoskeleton-associated protein PLEK2 is mainly involved in cytoskeletal protein recombination and cell stretch migration regulation, which is closely related to EMT. However, little is known about the link between nicotine/α5-nAChR and PLEK2 in lung adenocarcinoma (LUAD). Here, we identified a link between α5-nAChR and PLEK2 in LUAD. α5-nAChR expression was correlated with PLEK2 expression, smoking status and lower survival in vivo. α5-nAChR mediated nicotine-induced PLEK2 expression via STAT3. α5-nAChR/PLEK2 signaling is involved in LUAD cell migration, invasion and stemness. Moreover, PLEK2 was found to interact with CFL1 in nicotine-induced EMT in LUAD cells. Furthermore, the functional link among α5-nAChR, PLEK2 and CFL1 was confirmed in mouse xenograft tissues and human LUAD tissues. These findings reveal a novel α5-nAChR/PLEK2/CFL1 pathway involved in nicotine-induced LUAD progression.

Radiation-Triggered Selenium-Engineered Mesoporous Silica Nanocapsules for RNAi Therapy in Radiotherapy-Resistant Glioblastoma

Radiotherapy-resistant glioblastoma (rrGBM) remains a significant clinical challenge because of high infiltrative growth characterized by activation of antiapoptotic signal transduction. Herein, we describe an efficiently biodegradable selenium-engineered mesoporous silica nanocapsule, initiated by high-energy X-ray irradiation and employed for at-site RNA interference (RNAi) to inhibit rrGBM invasion and achieve maximum therapeutic benefit. Our radiation-triggered RNAi nanocapsule showed high physiological stability, good blood-brain barrier transcytosis, and potent rrGBM accumulation. An intratumoral RNAi nanocapsule permitted low-dose X-ray radiation-triggered dissociation for cofilin-1 knockdown, inhibiting rrGBM infiltration. More importantly, tumor suppression was further amplified by electron-affinity aminoimidazole products converted from metronidazole polymers under X-ray radiation-exacerbated hypoxia, which sensitized cell apoptosis to ionizing radiation by fixing reactive oxygen species-induced DNA lesions. In vivo experiments confirmed that our RNAi nanocapsule reduced tumor growth and invasion, prolonging survival in an orthotopic rrGBM model. Generally, we present a promising radiosensitizer that would effectively improve rrGBM-patient outcomes with low-dose X-ray irradiation.

LACTB suppresses migration and invasion of glioblastoma via downregulating RHOC/Cofilin signaling pathway

Glioblastoma (GBM) is the most malignant tumor in human brain. High invasiveness of this tumor is the main reason causing treatment failure and recurrence. Previous study has found that LACTB is a novel tumor suppressor in breast cancer. Moreover, the function of LACTB in other tumors and mechanisms involving LACTB were also reported. However, the role and relevant mechanisms of LACTB in GBM invasion remains to be revealed. Our aim is to investigate the role LACTB in GBM migration and invasion. We found that LACTB was downregulated in gliomas compared to normal brain tissues. Overexpression of LACTB suppressed migration and invasion of LN229 and U87 cell lines. Mechanistically, LACTB overexpression downregulated the mesenchymal markers. Moreover, LACTB overexpression downregulated the expression of RHOC and inhibited RHOC/Cofilin signaling pathway. The study suggests that LACTB suppresses migration and invasion of GBM cell lines via downregulating RHOC/Cofilin signaling pathway. These findings suggest that LACTB may be a potential treatment target of GBM.

Chaperonin-Containing TCP1 Subunit 5 Protects Against the Effect of Mer Receptor Tyrosine Kinase Knockdown in Retinal Pigment Epithelial Cells by Interacting With Filamentous Actin and Activating the LIM-Kinase 1/Cofilin Pathway

Retinitis pigmentosa (RP), characterized by the gradual loss of rod and cone photoreceptors that eventually leads to blindness, is the most common inherited retinal disorder, affecting more than 2.5 million people worldwide. However, the underlying pathogenesis of RP remains unclear and there is no effective cure for RP. Mutations in the Mer receptor tyrosine kinase (MERTK) gene induce the phagocytic dysfunction of retinal pigment epithelium (RPE) cells, leading to RP. Studies have indicated that filamentous actin (F-actin)—which is regulated by chaperonin-containing TCP1 subunit 5 (CCT5)—plays a vital role in phagocytosis in RPE cells. However, whether CCT5/F-actin signaling is involved in MERTK-associated RP remains largely unknown. In the present study, we specifically knocked down MERTK and CCT5 through siRNA transfection and examined the expression of CCT5 and F-actin in human primary RPE (HsRPE) cells. We found that MERTK downregulation inhibited cell proliferation, migration, and phagocytic function; significantly decreased the expression of F-actin; and disrupted the regular arrangement of F-actin. Importantly, our findings firstly indicate that CCT5 interacts with F-actin and is inhibited by MERTK siRNA in HsRPE cells. Upregulating CCT5 using CCT5-specific lentiviral vectors (CCT5-Le) rescued the cell proliferation, migration, and phagocytic function of HsRPE cells under the MERTK knockdown condition by increasing the expression of F-actin and restoring its regular arrangement via the LIMK1/cofilin, but not the SSH1/cofilin, pathway. In conclusion, CCT5 protects against the effect of MERTK knockdown in HsRPE cells and demonstrates the potential for effective treatment of MERTK-associated RP.

Targeted mutagenesis in Nicotiana tabacum ADF gene using shockwave-mediated ribonucleoprotein delivery increases osmotic stress tolerance

DNA-free genome editing involves the direct introduction of ribonucleoprotein (RNP) complexes into cells, but this strategy has rarely been successful in plants. In the present study, we describe a new technique for the introduction of RNPs into plant cells involving the generation of cavitation bubbles using a pulsed laser. The resulting shockwave achieves the efficient transfection of walled cells in tissue explants by creating transient membrane pores. RNP-containing cells were rapidly identified by fluorescence microscopy, followed by regeneration and the screening of mutant plants by high-resolution melt analysis. We used this technique in Nicotiana tabacum to target the endogenous phytoene desaturase (PDS) and actin depolymerizing factor (ADF) genes. Genome-edited plants were produced with an efficiency of 35.2% for PDS and 16.5% for ADF. Further we evaluated the physiological, cellular and molecular effects of ADF mutations in T2 mutant plants under drought and salinity stress. The results suggest that ADF acts as a key regulator of osmotic stress tolerance in plants.

Lysine 2-hydroxyisobutyrylation proteomics reveals protein modification alteration in the actin cytoskeleton pathway of oral squamous cell carcinoma

As the most commonplace malignant carcinoma in the oral cavity, oral squamous cell carcinoma (OSCC) is highly invasive and prone to recurrence. The nosogenesis of OSCC are affected by epigenetics. Recently, a newly-found post-translational modification of lysine, 2-hydroxyisobutylation (Khib), has been proved to play a critical role in biological regulation. However, no research has evaluated the mechanism of Khib in oral cancer. Here, we performed liquid chromatography-mass spectrometry-based quantitative proteomics combined with bioinformatics analysis to reveal and evaluate Khib protein alterations in OSCC. Numerous proteins in OSCC undergo up-regulated modification of Khib. We quantified and identified 967 proteins with differential expression levels, and 617 2-hydroxyisobutylated proteins with 938 Khib sites. Among them, 125 proteins both differentially expressed and accompanied by obvious Khib modification were further identified and analyzed through KEGG-based and ingenuity pathway analysis (IPA). These proteins are enriched in the actin cytoskeleton regulatory pathway, and IPA predicted that they alter the state of actin aggregation and stability, hence impacting and regulating the actin cytoskeleton in OSCC. This is the first 2-hydroxyisobutylated modification proteomics performed for OSCC. Khib protein is significantly concentrated in the actin cytoskeleton regulatory pathway, indicating that this pathway may mediate the tumorigenesis or exacerbation of OSCC. SIGNIFICANCE: This is the first study that revealed the alterations of Khib protein in oral squamous cell carcinoma through LC-MS/MS-based modified proteomic. Our data showed that the protein in the actin cytoskeleton regulatory pathway was underwent significant Khib modification and abundance changes. We applied predictive function in IPA software to analyze and clarify that the aggregation of actin and the regulation of actin stability that mediated by the actin cytoskeleton regulatory pathway may be the potential mechanism of the occurrence and development of oral squamous cell carcinoma. Our research broadens the understanding of the pathogenesis of oral squamous cell carcinoma and provides new insights for future research.

Cofilin and Actin Dynamics: Multiple Modes of Regulation and Their Impacts in Neuronal Development and Degeneration

Proteins of the actin depolymerizing factor (ADF)/cofilin family are ubiquitous among eukaryotes and are essential regulators of actin dynamics and function. Mammalian neurons express cofilin-1 as the major isoform, but ADF and cofilin-2 are also expressed. All isoforms bind preferentially and cooperatively along ADP-subunits in F-actin, affecting the filament helical rotation, and when either alone or when enhanced by other proteins, promotes filament severing and subunit turnover. Although self-regulating cofilin-mediated actin dynamics can drive motility without post-translational regulation, cells utilize many mechanisms to locally control cofilin, including cooperation/competition with other proteins. Newly identified post-translational modifications function with or are independent from the well-established phosphorylation of serine 3 and provide unexplored avenues for isoform specific regulation. Cofilin modulates actin transport and function in the nucleus as well as actin organization associated with mitochondrial fission and mitophagy. Under neuronal stress conditions, cofilin-saturated F-actin fragments can undergo oxidative cross-linking and bundle together to form cofilin-actin rods. Rods form in abundance within neurons around brain ischemic lesions and can be rapidly induced in neurites of most hippocampal and cortical neurons through energy depletion or glutamate-induced excitotoxicity. In ~20% of rodent hippocampal neurons, rods form more slowly in a receptor-mediated process triggered by factors intimately connected to disease-related dementias, e.g., amyloid-β in Alzheimer’s disease. This rod-inducing pathway requires a cellular prion protein, NADPH oxidase, and G-protein coupled receptors, e.g., CXCR4 and CCR5. Here, we will review many aspects of cofilin regulation and its contribution to synaptic loss and pathology of neurodegenerative diseases.

Cyclovirobuxine D Induces Apoptosis and Mitochondrial Damage in Glioblastoma Cells Through ROS-Mediated Mitochondrial Translocation of Cofilin

Background

Cyclovirobuxine D (CVBD), a steroidal alkaloid, has multiple pharmacological activities, including anti-cancer activity. However, the anti-cancer effect of CVBD on glioblastoma (GBM) has seldom been investigated. This study explores the activity of CVBD in inducing apoptosis of GBM cells, and examines the related mechanism in depth.

Methods

GBM cell lines (T98G, U251) and normal human astrocytes (HA) were treated with CVBD. Cell viability was examined by CCK-8 assay, and cell proliferation was evaluated by cell colony formation counts. Apoptosis and mitochondrial superoxide were measured by flow cytometry. All protein expression levels were determined by Western blotting. JC-1 and CM-H₂DCFDA probes were used to evaluate the mitochondrial membrane potential (MMP) change and intracellular ROS generation, respectively. The cell ultrastructure was observed by transmission electron microscope (TEM). Colocalization of cofilin and mitochondria were determined by immunofluorescence assay.

Results

CVBD showed a greater anti-proliferation effect on the GBM cell lines, T98G and U251, than normal human astrocytes in dose- and time-dependent manners. CVBD induced apoptosis and mitochondrial damage in GBM cells. We found that CVBD led to mitochondrial translocation of cofilin. Knockdown of cofilin attenuated CVBD-induced apoptosis and mitochondrial damage. Additionally, the generation of ROS and mitochondrial superoxide was also induced by CVBD in a dose-dependent manner. N-acetyl-L-cysteine (NAC) and mitoquinone (MitoQ) pre-treatment reverted CVBD-induced apoptosis and mitochondrial damage. MitoQ pretreatment was able to block the mitochondrial translocation of cofilin caused by CVBD.

Conclusions

Our data revealed that CVBD induced apoptosis and mitochondrial damage in GBM cells. The underlying mechanism is related to mitochondrial translocation of cofilin caused by mitochondrial oxidant stress.

The Significant Role of the Microfilament System in Tumors

Actin is the structural protein of microfilaments, and it usually exists in two forms: monomer and polymer. Among them, monomer actin is a spherical molecule composed of a polypeptide chain, also known as spherical actin. The function of actin polymers is to produce actin filaments, so it is also called fibroactin. The actin cytoskeleton is considered to be an important subcellular filament system. It interacts with numerous relevant proteins and regulatory cells, regulating basic functions, from cell division and muscle contraction to cell movement and ensuring tissue integrity. The dynamic reorganization of the actin cytoskeleton has immense influence on the progression and metastasis of cancer as well. This paper explores the significance of the microfilament network, the dynamic changes of its structure and function in the presence of a tumor, the formation process around the actin system, and the relevant proteins that may be target molecules for anticancer drugs so as to provide support and reference for interlinked cancer treatment research in the future.

GTPases, genome, actin: A hidden story in DNA damage response and repair mechanisms

The classical small Rho GTPase (Rho, Rac, and Cdc42) protein family is mainly responsible for regulating cell motility and polarity, membrane trafficking, cell cycle control, and gene transcription. Cumulative recent evidence supports important roles for these proteins in the maintenance of genomic stability. Indeed, DNA damage response (DDR) and repair mechanisms are some of the prime biological processes that underlie several disease phenotypes, including genetic disorders, cancer, senescence, and premature aging. Many reports guided by different experimental approaches and molecular hypotheses have demonstrated that, to some extent, direct modulation of Rho GTPase activity, their downstream effectors, or actin cytoskeleton regulation contribute to these cellular events. Although much attention has been paid to this family in the context of canonical actin cytoskeleton remodeling, here we provide a contextualized review of the interplay between Rho GTPase signaling pathways and the DDR and DNA repair signaling components. Interesting questions yet to be addressed relate to the spatiotemporal dynamics of this collective response and whether it correlates with different subcellular pools of Rho GTPases. We highlight the direct and indirect targets, some of which still lack experimental validation data, likely associated with Rho GTPase activation that provides compelling evidence for further investigation in DNA damage-associated events and with potential therapeutic applications in translational medicine.

Cofilin: A Promising Protein Implicated in Cancer Metastasis and Apoptosis

Cofilin is an actin-binding protein that regulates filament dynamics and depolymerization. The over-expression of cofilin is observed in various cancers, cofilin promotes cancer metastasis by regulating cytoskeletal reorganization, lamellipodium formation and epithelial-to-mesenchymal transition. Clinical treatment of cancer regarding cofilin has been explored in aspects of tumor cells apoptosis and cofilin related miRNAs. This review addresses the structure and phosphorylation of cofilin and describes recent findings regarding the function of cofilin in regulating cancer metastasis and apoptosis in tumor cells.

Arabidopsis calcium-dependent protein kinase 3 regulates actin cytoskeleton organization and immunity

Pattern-triggered immunity and effector-triggered immunity are two primary forms of innate immunity in land plants. The molecular components and connecting nodes of pattern-triggered immunity and effector-triggered immunity are not fully understood. Here, we report that the Arabidopsis calcium-dependent protein kinase CPK3 is a key regulator of both pattern-triggered immunity and effector-triggered immunity. In vitro and in vivo phosphorylation assays, coupled with genetic and cell biology-based analyses, show that actin-depolymerization factor 4 (ADF4) is a physiological substrate of CPK3, and that phosphorylation of ADF4 by CPK3 governs actin cytoskeletal organization associated with pattern-triggered immunity. CPK3 regulates stomatal closure induced by flg22 and is required for resistance to Pst DC3000. Our data further demonstrates that CPK3 is required for resistance to Pst DC3000 carrying the effector AvrPphB. These results suggest that CPK3 is a missing link between cytoskeleton organization, pattern-triggered immunity and effector-triggered immunity.

Remodelling of the actin cytoskeleton occurs during plant immune responses to pathogens. Here Lu et al. show that this process requires the calcium-dependent kinase CPK3 which phosphorylates actin depolymerizing factor 4 and is required for both PAMP and effector-triggered immunity in Arabidopsis.

Role of Cofilin in Alzheimer's Disease

Alzheimer's disease (AD) is a degenerative neurological disease and has an inconspicuous onset and progressive development. Clinically, it is characterized by severe dementia manifestations, including memory impairment, aphasia, apraxia, loss of recognition, impairment of visual-spatial skills, executive dysfunction, and changes in personality and behavior. Its etiology is unknown to date. However, several cellular biological signatures of AD have been identified such as synaptic dysfunction, β-amyloid plaques, hyperphosphorylated tau, cofilin-actin rods, and Hirano bodies which are related to the actin cytoskeleton. Cofilin is one of the most affluent and common actin-binding proteins and plays a role in cell motility, migration, shape, and metabolism. They also play an important role in severing actin filament, nucleating, depolymerizing, and bundling activities. In this review, we summarize the structure of cofilins and their functional and regulating roles, focusing on the synaptic dysfunction, β-amyloid plaques, hyperphosphorylated tau, cofilin-actin rods, and Hirano bodies of AD.

RHOAming Through the Nucleotide Excision Repair Pathway as a Mechanism of Cellular Response Against the Effects of UV Radiation

Typical Rho GTPases include the enzymes RhoA, Rac1, and Cdc42 that act as molecular switches to regulate essential cellular processes in eukaryotic cells such as actomyosin dynamics, cell cycle, adhesion, death and differentiation. Recently, it has been shown that different conditions modulate the activity of these enzymes, but their functions still need to be better understood. Here we examine the interplay between RhoA and the NER (Nucleotide Excision Repair) pathway in human cells exposed to UVA, UVB or UVC radiation. The results show high levels and accumulation of UV-induced DNA lesions (strand breaks and cyclobutane pyrimidine dimers, CPDs) in different cells with RhoA loss of function (LoF), either by stable overexpression of negative dominant RhoA (RhoA-N19 mutant), by inhibition with C3 toxin or by transient silencing with siRNA. Cells under RhoA LoF showed reduced levels of γH2AX, p-Chk1 (Ser345) and p-p53 (Ser15) that reflected causally in their accumulation in G1/S phases, in low survival rates and in reduced cell proliferation, also in accordance with the energy of applied UV light. Even NER-deficient cells (XPA, XPC) or DNA translesion synthesis (TLS)-deficient cells (XPV) showed substantial hypersensitivity to UV effects when previously submitted to RhoA LoF. In contrast, analyses of apoptosis, necrosis, autophagy and senescence revealed that all cells displaying normal levels of active RhoA (RhoA-GTP) are more resistant to UV-promoted cell death. This work reaffirms the role of RhoA protein signaling in protecting cells from damage caused by UV radiation and demonstrates relevant communicating mechanisms between actin cytoskeleton and genomic stability.

Loci associated with genomic damage levels in chronic kidney disease patients and controls

Chronic kidney disease (CKD) is a multifactorial disorder with an important genetic component, and several studies have demonstrated potential associations with allelic variants. In addition, CKD patients are also characterized by high levels of genomic damage. Nevertheless, no studies have established relationships between DNA damage, or genomic instability present in CKD patients, and gene polymorphisms. To fill in this gap, the potential role of polymorphisms in genes involved in base excision repair (OGG1, rs1052133; MUTYH, rs3219489; XRCC1, rs25487), nucleotide excision repair (ERCC2/XPD, rs1799793, rs171140, rs13181; ERCC4, rs3136166); phase II metabolism (GSTP1, rs749174; GSTO1, rs2164624; GSTO2, rs156697), and antioxidant enzymes (SOD1, rs17880135, rs1041740, rs202446; SOD2, rs4880; CAT, rs1001179; GPX1, rs17080528; GPX3, rs870406: GPX4, rs713041) were inquired. In addition, some genes involved in CKD (AGT, rs5050; GLO1, rs386572987; SHROOM3, rs17319721) were also evaluated. The genomic damage, the genomic instability, and oxidative damage were evaluated by using the micronucleus and the comet assay in 589 donors (415 CKD patients and 174 controls). Our results showed significant associations between genomic damage and genes directly involved in DNA repair pathways (XRCC1, and ERCC2), and with genes encoding for antioxidant enzymes (SOD1 and GPX1). GSTO2, as a gene involved in phase II metabolism, and MUTYH showed also an association with genomic instability. Interestingly, the three genes associated with CKD (AGT, GLO1, and SHROOM3) showed associations with both the high levels of oxidatively damaged DNA and genomic instability. These results support our view that genomic instability can be considered a biomarker of the CKD status.

Phosphorylation Time-Course Study of the Response during Adenovirus Type 2 Infection

PTMs such as phosphorylations are usually involved in signal transduction pathways. To investigate the temporal dynamics of phosphoproteome changes upon viral infection, a model system of IMR-90 cells infected with human adenovirus type 2 (Ad2) is used in a time-course quantitative analysis combining titanium dioxide (TiO₂ ) particle enrichment and SILAC-MS. Quantitative data from 1552 phosphorylated sites clustered the highly altered phosphorylated sites to the signaling by rho family GTPases, the actin cytoskeleton signaling, and the cAMP-dependent protein kinase A signaling pathways. Their activation is especially pronounced at early time post-infection. Changes of several phosphorylated sites involved in the glycolysis pathway, related to the activation of the Warburg effect, point at virus-induced energy production. For Ad2 proteins, 32 novel phosphorylation sites are identified and as many as 52 phosphorylated sites on 17 different Ad2 proteins are quantified, most of them at late time post-infection. Kinase predictions highlighted activation of PKA, CDK1/2, MAPK, and CKII. Overlaps of kinase motif sequences for viral and human proteins are observed, stressing the importance of phosphorylation during Ad2 infection.

Simultaneous Inhibition of BCR-ABL1 Tyrosine Kinase and PAK1/2 Serine/Threonine Kinase Exerts Synergistic Effect against Chronic Myeloid Leukemia Cells

Tyrosine kinase inhibitors (TKIs) revolutionized the treatment of chronic myeloid leukemia in the chronic phase (CML-CP). However, it is unlikely that they can completely “cure” the disease. This might be because some subpopulations of CML-CP cells such as stem and progenitor cells are resistant to chemotherapy, even to the new generation of TKIs. Therefore, it is important to look for new methods of treatment to improve therapeutic outcomes. Previously, we have shown that class I p21-activated serine/threonine kinases (PAKs) remained active in TKI-naive and TKI-treated CML-CP leukemia stem and early progenitor cells. In this study, we aimed to determine if simultaneous inhibition of BCR-ABL1 oncogenic tyrosine kinase and PAK1/2 serine/threonine kinase exert better anti-CML effect than that of individual treatments. PAK1 was inhibited by small-molecule inhibitor IPA-3 (p21-activated kinase inhibitor III), PAK2 was downregulated by specific short hairpin RNA (shRNA), and BCR-ABL1 tyrosine kinase was inhibited by imatinib (IM). The studies were conducted by using (i) primary CML-CP stem/early progenitor cells and normal hematopoietic counterparts isolated from the bone marrow of newly diagnosed patients with CML-CP and from healthy donors, respectively, (ii) CML-blast phase cell lines (K562 and KCL-22), and (iii) from BCR-ABL1-transformed 32Dcl3 cell line. Herein, we show that inhibition of the activity of PAK1 and/or PAK2 enhanced the effect of IM against CML cells without affecting the normal cells. We observed that the combined use of IM with IPA-3 increased the inhibition of growth and apoptosis of leukemia cells. To evaluate the type of interaction between the two drugs, we performed median effect analysis. According to our results, the type and strength of drug interaction depend on the concentration of the drugs tested. Generally, combination of IM with IPA-3 at the 50% of the cell kill level (EC50) generated synergistic effect. Based on our results, we hypothesize that IM, a BCR-ABL1 tyrosine kinase inhibitor, combined with a PAK1/2 inhibitor facilitates eradication of CML-CP cells.

Cofilin 2 in Serum as a Novel Biomarker for Alzheimer's Disease in Han Chinese

The identification of biomarkers of Alzheimer’s disease (AD) is an important and urgent area of study, not only to aid in the early diagnosis of AD, but also to evaluate potentially new anti-AD drugs. The aim of this study was to explore cofilin 2 in serum as a novel biomarker for AD. The upregulation was observed in AD patients and different AD animal models compared to the controls, as well as in AD cell models. Memantine and donepezil can attenuate the upregulation of cofilin 2 expression in APP/PS1 mice. The serum levels of cofilin 2 in AD or mild cognitive impairment (MCI) patients were significantly higher compared to controls (AD: 167.9 ± 35.3 pg/mL; MCI: 115.9 ± 15.4 pg/mL; Control: 90.5 ± 27.1 pg/mL; p < 0.01). A significant correlation between cofilin 2 levels and cognitive decline was observed (r = –0.792; p < 0.001). The receiver operating characteristic curve (ROC) analysis showed the area under the curve (AUC) of cofilin 2 was 0.957, and the diagnostic accuracy was 80%, with 93% sensitivity and 87% specificity. The optimal cut-off value was 130.4 pg/ml. Our results indicate the possibility of serum cofilin 2 as a novel and non-invasive biomarker for AD. In addition, the expression of cofilin 2 was found to be significantly increased in AD compared to vascular dementia (VaD), and only an increased trend but not significant was detected in VaD compared to the controls. ROC analysis between AD and VaD showed that the AUC was 0.824, which could indicate a role of cofilin 2 as a biomarker in the differential diagnosis between AD and VaD.

Identification of Cofilin-1 and Destrin as Potential Early-warning Biomarkers for Gamma Radiation in Mouse Liver Tissues

Gamma radiation causes cell injury and leads to an increased risk of cancer, so it is of practical significance to identify biomarkers for gamma radiation. We used proteomic analysis to identify differentially expressed proteins in liver tissues of C57BL/6J mice treated with gamma radiation from Cs for 360 d. We confirmed obvious pathological changes in mouse liver tissues after irradiation. Compared with the control group, 74 proteins showed a fold change of ≥1.5 in the irradiated groups. We selected 24 proteins for bioinformatics analysis and peptide mass fingerprinting and found that 20 of the identified proteins were meaningful. These proteins were associated with tumorigenesis, tumor suppression, catalysis, cell apoptosis, cytoskeleton, metabolism, gene transcription, T-cell response, and other pathways. We confirmed that both cofilin-1 and destrin were up regulated in the irradiated groups by western blot and real-time polymerase chain reaction. Our findings indicate that cofilin-1 and destrin are sensitive to gamma radiation and may be potential biomarkers for gamma radiation. Whether these proteins are involved in radiation-induced tumorigenesis requires further investigation.

c-Myc activation promotes cofilin-mediated F-actin cytoskeleton remodeling and telomere homeostasis as a response to oxidant-based DNA damage in medulloblastoma cells

Medulloblastoma (MB) is a common and highly aggressive pediatric brain tumor of a heterogeneous nature. According to transcriptome-based profiling, four molecular subgroups of MB have been revealed, namely WNT, SHH, Group 3 and Group 4. High MYC mRNA expression and MYC gene amplification in MB have been considered as indicators of poor prognosis. However, the role of c-Myc in MB biology is still not well established. In the present study, the effects of c-Myc activation in UW228-MycER MB cell line were investigated using 4-hydroxytamoxifen (4-OHT) induction system. Upon 4-OHT stimulation, an increase in metabolic activity, large-cell/anaplastic (LC/A) phenotype and oxidative stress-mediated DNA damage were observed. However, 53BP1 foci were not implicated in DNA damage response. Instead, cofilin nuclear translocation, changes in F-actin cytoskeleton and the levels of cytoskeletal proteins were shown. Moreover, the telomere length was found to be unaffected that may be associated with the upregulation of TRF proteins. Transcription of nascent RNA (synthesis of new rRNA) and the expression of RNA polymerase I-specific transcription initiation factor RRN3/TIF-IA were also elevated. Moreover, increased levels of DNMT2, a modulator of stress responses, were observed. A small fraction of cells responded differently as oncogene-induced senescence was also noticed. We postulate that c-Myc-mediated modulation of genetic stability of MB cells may trigger cellular heterogeneity and affect adaptive responses to changing environment.

Associations of the expression levels of genes involved in CFL2b and MyHC isoform type changes in longissimus dorsi muscle of HeBao and Large White pigs (Sus scrofa) during postnatal growth

This study aimed to compare the patterns of postnatal transformation of myosin heavy chain (MyHC) isoform types in the longissimus dorsi (LD) muscle between HeBao (HB) and Large White (LW) pigs, and assess the association of porcine cofilin2b (CFL2b) mRNA abundance with changes of myofiber type composition. The four MyHC isoforms (MyHC-1, -2a, -2b, and -2x) of the LD muscle were assessed for mRNA levels in 28 HB and 28 LW pigs by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The associations of CFL2b mRNA expression and myofiber type (MyHC-1, -2a, -2b, and -2x) changes were analyzed by RT-qPCR. Although the mRNA expression patterns of MyHCs were different between the two breeds, they had similar expression levels. During postnatal growth, relative CFL2b abundance was gradually increased, with dramatic changes observed after 90 d between the two breeds (P < 0.01). Further analysis revealed significant positive correlations of CFL2b gene expression with MyHC-1/slow (HB: r = 0.871), MyHC-2b [LW: r = 0.881 (P < 0.01)], and MyHC-2x (HB: r = 0.795, LW: r = 0.814), and a significant negative correlation with MyHC-1/slow [r = −0.938 (P < 0.01)] in LW. No significant associations of CFL2b expression with MyHC-2a (HB: r = −0. 195, r = −0.697) and MyHC-2b (HB: r = 0.493) were found. Our findings suggested that HB pigs had different muscle development mechanisms in the LD muscle compared with LW, and the CFL2b expression difference could affect the levels of myofiber types which could account for meat quality differences. HB pigs possessed less glycolytic, with more oxidative metabolism and better meat quality traits compared with LW pigs at different growth stages.

Intracellular ion and protein nanoparticle-induced osmotic pressure modify astrocyte swelling and brain edema in response to glutamate stimuli

Intracellular tension activity plays a crucial role in cytotoxic brain edema and astrocyte swelling. Here, a few genetically encoded FRET-based tension probes were designed to detect cytoskeletal structural tension optically, including their magnitude and vectors. The astrocyte swelling resulted in GFAP tension increment, which is associated with the antagonistic effect of inward microfilaments (MFs) and microtubules (MTs) forces. In glutamate-induced astrocyte swelling, GFAP tension rise resulted from outward ion and protein nanoparticle-induced osmotic pressure (PN-OP) increases, where PN-OP could be elicited by MF and MT depolymerization, protein nanoparticle production, and activation of cofilin and stathmin-1. Attenuation of both ion osmotic pressure and PN-OP by drug combinations, together with free-radical scavenger, relieved cerebral edema in vivo. The study suggests that intracellular osmotic pressure (especially PN-OP) has a pivotal role in glutamate-induced astrocyte swelling and brain edema. Recovery of cytoplasmic potential is a promising target to develop new drugs and cure brain edema.

Transcriptional effects of actin-binding compounds: the cytoplasm sets the tone

Actin has emerged as a versatile regulator of gene transcription. Cytoplasmatic actin regulates mechanosensitive-signaling pathways such as MRTF-SRF and Hippo-YAP/TAZ. In the nucleus, both polymerized and monomeric actin directly interfere with transcription-associated molecular machineries. Natural actin-binding compounds are frequently used tools to study actin-related processes in cell biology. However, their influence on transcriptional regulation and intranuclear actin polymerization is poorly understood to date. Here, we analyze the effects of two representative actin-binding compounds, Miuraenamide A (polymerizing properties) and Latrunculin B (depolymerizing properties), on transcriptional regulation in primary cells. We find that actin stabilizing and destabilizing compounds inversely shift nuclear actin levels without a direct influence on polymerization state and intranuclear aspects of transcriptional regulation. Furthermore, we identify Miuraenamide A as a potent inducer of G-actin-dependent SRF target gene expression. In contrast, the F-actin-regulated Hippo-YAP/TAZ axis remains largely unaffected by compound-induced actin aggregation. This is due to the inability of AMOTp130 to bind to the amorphous actin aggregates resulting from treatment with miuraenamide. We conclude that actin-binding compounds predominantly regulate transcription via their influence on cytoplasmatic G-actin levels, while transcriptional processes relying on intranuclear actin polymerization or functional F-actin networks are not targeted by these compounds at tolerable doses.

Cryopreserved Cells Regeneration Monitored by Atomic Force Microscopy and Correlated With State of Cytoskeleton and Nuclear Membrane

Atomic force microscopy (AFM) helps to describe and explain the mechanobiological properties of living cells on the nanoscale level under physiological conditions. The stiffness of cells is an important parameter reflecting cell physiology. Here, we have provided the first study of the stiffness of cryopreserved cells during post-thawing regeneration using AFM combined with confocal fluorescence microscopy. We demonstrated that the nonfrozen cell stiffness decreased proportionally to the cryoprotectant concentration in the medium. AFM allowed us to map cell surface reconstitution in real time after a freeze/thaw cycle and to monitor the regeneration processes at different depths of the cell and even different parts of the cell surface (nucleus and edge). Fluorescence microscopy showed that the cytoskeleton in fibroblasts, though damaged by the freeze/thaw cycle, is reconstructed after long-term plating. Confocal microscopy confirmed that structural changes affect the nuclear envelopes in cryopreserved cells. AFM nanoindentation analysis could be used as a noninvasive method to identify cells that have regenerated their surface mechanical properties with the proper dynamics and to a sufficient degree. This identification can be important particularly in the field of in vitro fertilization and in future cell-based regeneration strategies.

Phosphorylation of the Cytoskeletal Protein CAP1 Regulates Non-Small Cell Lung Cancer Survival and Proliferation by GSK3β

Adenylate cyclase-associated protein 1 (CAP1) is an evolutionarily conserved protein that regulates actin dynamics. Our previous study indicates that CAP1 is overexpressed in NSCLC tissues and correlated with poor clinical outcomes. Further establishing the role and dissecting underlying mechanisms are imperative before targeting CAP1 can become a possibility for cancer treatment. Here we report our findings that knockdown of CAP1 inhibited cell proliferation and induced apoptosis in vitro and in vivo. Moreover, phosphor mutants of CAP1 at the S307/S309 regulatory site had compromised rescue effects for both the invasiveness and the proliferation in CAP1-knockdown cells and GSK3β kinase inhibitor LiCl inhibited cell phosphorylation site S307/S309 by up-regulating the expression of p53, BAK, BAD and cleaved PARP induced ROS production, decreased lung cancer cell viability, adhesion, proliferation, migration and invasion, and induction of apoptosis. These novel mechanistic insights may ultimately open up avenues for strategies targeting CAP1 in the treatment of lung cancer, tailored for specific types of the highly diverse disease.

Scorpins in the DNA Damage Response

The DNA Damage Response (DDR) is a complex signaling network that comes into play when cells experience genotoxic stress. Upon DNA damage, cellular signaling pathways are rewired to slow down cell cycle progression and allow recovery. However, when the damage is beyond repair, cells activate complex and still not fully understood mechanisms, leading to a complete proliferative arrest or cell death. Several conventional and novel anti-neoplastic treatments rely on causing DNA damage or on the inhibition of the DDR in cancer cells. However, the identification of molecular determinants directing cancer cells toward recovery or death upon DNA damage is still far from complete, and it is object of intense investigation. SPRY-containing RAN binding Proteins (Scorpins) RANBP9 and RANBP10 are evolutionarily conserved and ubiquitously expressed proteins whose biological functions are still debated. RANBP9 has been previously implicated in cell proliferation, survival, apoptosis and migration. Recent studies also showed that RANBP9 is involved in the Ataxia Telangiectasia Mutated (ATM) signaling upon DNA damage. Accordingly, cells lacking RANBP9 show increased sensitivity to genotoxic treatment. Although there is no published evidence, extensive protein similarities suggest that RANBP10 might have partially overlapping functions with RANBP9. Like RANBP9, RANBP10 bears sites putative target of PIK-kinases and high throughput studies found RANBP10 to be phosphorylated following genotoxic stress. Therefore, this second Scorpin might be another overlooked player of the DDR alone or in combination with RANBP9. This review focuses on the relatively unknown role played by RANBP9 and RANBP10 in responding to genotoxic stress.

Proteomic Analysis of Normal and Cancer Cervical Cell Lines Reveals Deregulation of Cytoskeleton-associated Proteins

BACKGROUND

Both HPV-positive and -negative cervical cancers are primarily associated with features of cell cycle and cytoskeletal disruption; however, the actual biological processes affected remain elusive. To this end, we systematically characterized the intracellular proteomic profiles of four distinct and informative cervical cell lines.

MATERIALS AND METHODS

Cell extracts from a normal cervical (HCK1T) and three cervical cancer cell lines, one HPV-negative (C33A), and two HPV-positive, SiHa (HPV16+) and HeLa (HPV18+), were analyzed by 2-dimensional electrophoresis and differentially expressed proteins were identified by MALDI-TOF mass spectrometry, while differential expression was confirmed by western blot analysis.

RESULTS

In total, 113 proteins were found differentially expressed between the normal and the cervical cancer lines. Bioinformatics analysis revealed the actin cytoskeleton signaling pathway to be significantly affected, while up-regulation of cofilin-1, an actin depolymerizing factor, was documented and further validated by western blotting. Furthermore, two-way comparisons among the four cell lines, revealed a set of 18 informative differentially expressed proteins.

CONCLUSION

These novel identified proteins provide the impetus for further functional studies to dissect the mechanisms operating in the two distinct pathways of cervical carcinogenesis.

Global Quantitative Proteomics reveal Deregulation of Cytoskeletal and Apoptotic Signalling Proteins in Oral Tongue Squamous Cell Carcinoma

Oral malignancies remain to have higher morbidity and mortality rates owing to the poor understanding of the carcinogenesis and the lack of early detection and diagnosis. The lack of established biomarkers for oral tongue squamous cell carcinoma (OTSCC) resulted in aggressive multi-modality management less effective. Here, we report for the first time that a panel of potential markers identified from tongue tumor samples using two-dimensional-differential-in-gel-electrophoresis (2D-DIGE). Our approach of combining 2D-DIGE with tandem mass spectrometry identified 24 candidate proteins including cofilins, myosin light chain family members, annexins, serpins, HSPs and tropomyosins, with significant differential expression in tongue carcinomas as compared with their matched adjacent normal tissues. The expression levels of the identified proteins were further validated in larger cohort of Indian samples using qPCR. Most of the differentially regulated proteins are involved in actin cytoskeletal dynamics, drug resistance, immune system, inflammation and apoptotic signalling pathways and are known to play critical role in oral tumorigenesis. Taken together, the results from present investigation provide a valuable base for understanding the development and progression of OTSCC. The validated panel of proteins may be used as potential biomarkers for early detection as well as in predicting therapeutic outcome of OTSCC.

Wild-type p53 enhances endothelial barrier function by mediating RAC1 signalling and RhoA inhibition

Inflammation is the major cause of endothelial barrier hyper‐permeability, associated with acute lung injury and acute respiratory distress syndrome. This study reports that p53 “orchestrates” the defence of vascular endothelium against LPS, by mediating the opposing actions of Rac1 and RhoA in pulmonary tissues. Human lung microvascular endothelial cells treated with HSP90 inhibitors activated both Rac1‐ and P21‐activated kinase, which is an essential element of vascular barrier function. 17AAG increased the phosphorylation of both LIMK and cofilin, in contrast to LPS which counteracted those effects. Mouse lung microvascular endothelial cells exposed to LPS exhibited decreased expression of phospho‐cofilin. 17AAG treatment resulted in reduced levels of active cofilin. Silencing of cofilin pyridoxal phosphate phosphatase (PDXP) blocked the LPS‐induced hyper‐permeability, and P53 inhibition reversed the 17AAG‐induced PDXP down‐regulation. P190RHOGAP suppression enhanced the LPS‐triggered barrier dysfunction in endothelial monolayers. 17AAG treatment resulted in P190RHOGAP induction and blocked the LPS‐induced pMLC2 up‐regulation in wild‐type mice. Pulmonary endothelial cells from “super p53” mice, which carry additional p53‐tg alleles, exhibited a lower response to LPS than the controls. Collectively, our findings help elucidate the mechanisms by which p53 operates to enhance barrier function.

Protein levels of clusterin and glutathione synthetase in platelets allow for early detection of colorectal cancer

Colorectal cancer (CRC) is one of the most frequent malignancies in the Western world. Early tumor detection and intervention are important determinants on CRC patient survival. During early tumor proliferation, dissemination and angiogenesis, platelets store and segregate proteins actively and selectively. Hence, the platelet proteome is a potential source of biomarkers denoting early malignancy. By comparing protein profiles of platelets between healthy volunteers (n = 12) and patients with early- (n = 7) and late-stage (n = 5) CRCs using multiplex fluorescence two-dimensional gel electrophoresis (2D-DIGE), we aimed at identifying differentially regulated proteins within platelets. By inter-group comparisons, 94 differentially expressed protein spots were detected (p < 0.05) between healthy controls and patients with early- and late-stage CRCs and revealed distinct separations between all three groups in principal component analyses. 54 proteins of interest were identified by mass spectrometry and resulted in high-ranked Ingenuity Pathway Analysis networks associated with Cellular function and maintenance, Cellular assembly and organization, Developmental disorder and Organismal injury and abnormalities (p < 0.0001 to p = 0.0495). Target proteins were validated by multiplex fluorescence-based Western blot analyses using an additional, independent cohort of platelet protein samples [healthy controls (n = 15), early-stage CRCs (n = 15), late-stage CRCs (n = 15)]. Two proteins-clusterin and glutathione synthetase (GSH-S)-featured high impact and were subsequently validated in this independent clinical cohort distinguishing healthy controls from patients with early- and late-stage CRCs. Thus, the potential of clusterin and GSH-S as platelet biomarkers for early detection of CRC could improve existing screening modalities in clinical application and should be confirmed in a prospective multicenter trial.

Nuclear fragments of the neural cell adhesion molecule NCAM with or without polysialic acid differentially regulate gene expression

The neural cell adhesion molecule (NCAM) is the major carrier of polysialic acid (PSA) which modulates NCAM functions of neural cells at the cell surface. In previous studies, we have shown that stimulation of cultured neurons with surrogate NCAM ligands leads to the generation and nuclear import of PSA-lacking and -carrying NCAM fragments. Here, we show that the nuclear import of the PSA-carrying NCAM fragment is mediated by positive cofactor 4 and cofilin, which we identified as novel PSA-binding proteins. In the nucleus, the PSA-carrying NCAM fragment interacts via PSA with PC4 and cofilin, which are involved in RNA polymerase II-dependent transcription. Microarray analysis revealed that the nuclear PSA-carrying and -lacking NCAM fragments affect expression of different genes. By qPCR and immunoblot analysis we verified that the nuclear PSA-carrying NCAM fragment increases mRNA and protein expression of nuclear receptor subfamily 2 group F member 6, whereas the PSA-lacking NCAM fragment increases mRNA and protein expression of low density lipoprotein receptor-related protein 2 and α-synuclein. Differential gene expression evoked by nuclear NCAM fragments without and with PSA indicates that PSA-carrying and -lacking NCAM play different functional roles in the nervous system.

Cofilin-mediated Neuronal Apoptosis via p53 Translocation and PLD1 Regulation

Amyloid β (Aβ) accumulation is an early event in the pathogenesis of Alzheimer’s disease (AD), leading to mitochondrial and synaptic dysfunction, tau accumulation, and eventual neuronal death. While the p53 apoptotic pathway has clearly been associated with Aβ deposits and neuronal apoptosis, the critical upstream factors contributing to p53 activation in AD are not well understood. We have previously shown that cofilin activation plays a pivotal role in Aβ-induced mitochondrial and synaptic dysfunction. In this study, we show that activated cofilin (S3A) preferentially forms a complex with p53 and promotes its mitochondrial and nuclear localization, resulting in transcription of p53-responsive genes and promotion of apoptosis. Conversely, reduction of endogenous cofilin by knockdown or genetic deficiency inhibits mitochondrial and nuclear translocation of p53 in cultured cells and in APP/PS1 mice. This cofilin-p53 pro-apoptotic pathway is subject to negative regulation by PLD1 thorough cofilin inactivation and inhibition of cofilin/p53 complex formation. Finally, activated cofilin is unable to induce apoptosis in cells genetically lacking p53. These findings taken together indicate that cofilin coopts and requires the nuclear and mitochondrial pro-apoptotic p53 program to induce and execute apoptosis, while PLD1 functions in a regulatory multi-brake capacity in this pathway.

Plasma Level of hsa-miR-619-5p microRNA Is Associated with Prostatic Cancer Dissemination beyond the Capsule

Profiles of circulating microRNA in the plasma of patients with prostate cancer with pathomorphological stages pT2, pT3, and pT4 are analyzed. The level of circulating microRNA hsa-miR-619-5p is elevated in patients with extracapsular spreading of the tumor, increasing significantly from stage pT2 to stage pT4.

Cofilin-1 and Other ADF/Cofilin Superfamily Members in Human Malignant Cells

Identification of actin-depolymerizing factor homology (ADF-H) domains in the structures of several related proteins led first to the formation of the ADF/cofilin family, which then expanded to the ADF/cofilin superfamily. This superfamily includes the well-studied cofilin-1 (Cfl-1) and about a dozen different human proteins that interact directly or indirectly with the actin cytoskeleton, provide its remodeling, and alter cell motility. According to some data, Cfl-1 is contained in various human malignant cells (HMCs) and is involved in the formation of malignant properties, including invasiveness, metastatic potential, and resistance to chemotherapeutic drugs. The presence of other ADF/cofilin superfamily proteins in HMCs and their involvement in the regulation of cell motility were discovered with the use of various OMICS technologies. In our review, we discuss the results of the study of Cfl-1 and other ADF/cofilin superfamily proteins, which may be of interest for solving different problems of molecular oncology, as well as for the prospects of further investigations of these proteins in HMCs.

A proteomics approach to identifying novel protein targets involved in erinacine A-mediated inhibition of colorectal cancer cells' aggressiveness

Erinacine A, a major active component of a diterpenoid derivative isolated from Hericium erinaceus mycelium, has been demonstrated to exert anticancer effects. Herein, we present an investigation of the molecular mechanism of erinacine A induction associated with cancer cells’ aggressive status and death. A proteomic approach was used to purify and identify the differentially expressed proteins following erinacine A treatment and the mechanism of its action in apoptotic and the targets of erinacine A. Our results demonstrate that erinacine A treatment of HCT‐116 and DLD‐1 cells increased cell cytotoxicity and reactive oxygen species (ROS) production as well as decreased cell proliferation and invasiveness. Ten differentially displayed proteins were determined and validated in vitro and in vivo between the erinacine A‐treated and untreated groups. In addition, erinacine A time‐dependent induction of cell death and inhibitory invasiveness was associated with sustained phosphorylation of the PI3K/mTOR/p70S6K and ROCK1/LIMK2/Cofilin pathways. Furthermore, we demonstrated that erinacine A–induced HCT‐116 and DLD‐1 cells viability and anti‐invasion properties by up‐regulating the activation of PI3K/mTOR/p70S6K and production of ROS. Experiments involving specific inhibitors demonstrated that the differential expression of cofilin‐1 (COFL1) and profilin‐1 (PROF1) during erinacine A treatment could be involved in the mechanisms of HCT‐116 and DLD‐1 cells death and decreased aggressiveness, which occurred via ROCK1/LIMK2/Cofilin expression, with activation of the PI3K/mTOR/p70S6K signalling pathway. These findings elucidate the mechanism of erinacine A inhibiting the aggressive status of cells by activating PI3K/mTOR/p70S6K downstream signalling and the novel protein targets COF1 and PROF1; this could be a good molecular strategy to limit the aggressiveness of CRC cells.

Molecular Understanding of Growth Inhibitory Effect from Irradiated to Bystander Tumor Cells in Mouse Fibrosarcoma Tumor Model

Even though bystander effects pertaining to radiation risk assessment has been extensively studied, the molecular players of radiation induced bystander effect (RIBE) in the context of cancer radiotherapy are poorly known. In this regard, the present study is aimed to investigate the effect of irradiated tumor cells on the bystander counterparts in mouse fibrosarcoma (WEHI 164 cells) tumor model. Mice co-implanted with WEHI 164 cells γ-irradiated with a lethal dose of 15 Gy and unirradiated (bystander) WEHI 164 cells showed inhibited tumor growth, which was measured in terms of tumor volume and Luc⁺WEHI 164 cells based bioluminescence in vivo imaging. Histopathological analysis and other assays revealed decreased mitotic index, increased apoptosis and senescence in these tumor tissues. In addition, poor angiogenesis was observed in these tumor tissues, which was further confirmed by fluorescence imaging of tumor vascularisation and CD31 expression by immuno-histochemistry. Interestingly, the growth inhibitory bystander effect was exerted more prominently by soluble factors obtained from the irradiated tumor cells than the cellular fraction. Cytokine profiling of the supernatants obtained from the irradiated tumor cells showed increased levels of VEGF, Rantes, PDGF, GMCSF and IL-2 and decreased levels of IL-6 and SCF. Comparative proteomic analysis of the supernatants from the irradiated tumor cells showed differential expression of total 24 protein spots (21 up- and 3 down-regulated) when compared with the supernatant from the unirradiated control cells. The proteins which showed substantially higher level in the supernatant from the irradiated cells included diphosphate kinase B, heat shock cognate, annexin A1, angiopoietin-2, actin (cytoplasmic 1/2) and stress induced phosphoprotein 1. However, the levels of proteins like annexin A2, protein S100 A4 and cofilin was found to be lower in this supernatant. In conclusion, our results provided deeper insight about the damaging RIBE in an in vivo tumor model, which may have significant implication in improvement of cancer radiotherapy.

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.

Alterative Expression and Localization of Profilin 1/VASPpS157 and Cofilin 1/VASPpS239 Regulates Metastatic Growth and Is Modified by DHA Supplementation

Profilin 1, cofilin 1, and vasodialator-stimulated phosphoprotein (VASP) are actin-binding proteins (ABP) that regulate actin remodeling and facilitate cancer cell metastases. miR-17-92 is highly expressed in metastatic tumors and profilin1 and cofilin1 are predicted targets. Docosahexaenoic acid (DHA) inhibits cancer cell proliferation and adhesion. These studies tested the hypothesis that the metastatic phenotype is driven by changes in ABPs including alternative phosphorylation and/or changes in subcellular localization. In addition, we tested the efficacy of DHA supplementation to attenuate or inhibit these changes. Human lung cancer tissue sections were analyzed for F-actin content and expression and cellular localization of profilin1, cofilin1, and VASP (S157 or S239 phosphorylation). The metastatic phenotype was investigated in A549 and MLE12 cells lines using 8 Br-cAMP as a metastasis inducer and DHA as a therapeutic agent. Migration was assessed by wound assay and expression measured by Western blot and confocal analysis. miR-17-92 expression was measured by qRT-PCR. Results indicated increased expression and altered cellular distribution of profilin1/VASP(pS157), but no changes in cofilin1/VASP(pS239) in the human malignant tissues compared with normal tissues. In A549 and MLE12 cells, the expression patterns of profilin1/VASP(pS157) or cofilin1/VASP(pS239) suggested an interaction in regulation of actin dynamics. Furthermore, DHA inhibited cancer cell migration and viability, ABP expression and cellular localization, and modulated expression of miR-17-92 in A549 cells with minimal effects in MLE12 cells. Further investigations are warranted to understand ABP interactions, changes in cellular localization, regulation by miR-17-92, and DHA as a novel therapeutic. Mol Cancer Ther; 15(9); 2220-31. ©2016 AACR.

RIG-like Helicase Regulation of Chitinase 3-like 1 Axis and Pulmonary Metastasis

Chi3l1 is induced by a variety of cancers where it portends a poor prognosis and plays a key role in the generation of metastasis. However, the mechanisms that Chi3l1 uses to mediate these responses and the pathways that control Chi3l1-induced tumor responses are poorly understood. We characterized the mechanisms that Chi3l1 uses to foster tumor progression and the ability of the RIG-like helicase (RLH) innate immune response to control Chi3l1 elaboration and pulmonary metastasis. Here we demonstrate that RLH activation inhibits tumor induction of Chi3l1 and the expression of receptor IL-13Rα2 and pulmonary metastasis while restoring NK cell accumulation and activation, augmenting the expression of IFN-α/β, chemerin and its receptor ChemR23, p-cofilin, LIMK2 and PTEN and inhibiting BRAF and NLRX1 in a MAVS-dependent manner. These studies demonstrate that Chi3l1 is a multifaceted immune stimulator of tumor progression and metastasis whose elaboration and tissue effects are abrogated by RLH innate immune responses.