High-throughput Exploration of the Network Dependent on AKT1 in Mouse Ovarian Granulosa Cells

The PI3K/AKT signaling pathway is known to regulate a broad range of cellular processes, and it is often altered in several types of cancers. Recently, somatic AKT1 mutations leading to a strong activation of this kinase have been reported in juvenile granulosa cell tumors. However, the molecular role of AKT1 in the supporting cell lineage of the ovary is still poorly understood. To get insights into its function in such cells, we depleted Akt1 in murine primary granulosa cells and assessed the molecular consequences at both the transcript and protein levels. We were able to corroborate the involvement of AKT1 in the regulation of metabolism, apoptosis, cell cycle, or cytoskeleton dynamics in this ovarian cell type. Consistently, we showed in established granulosa cells that depletion of Akt1 provoked altered directional persistent migration and increased its velocity. This study also allowed us to put forward new direct and indirect targets of the kinase. Indeed, a series of proteins involved in intracellular transport and mitochondrial physiology were significantly affected by Akt1 depletion. Using in silico analyses, we also propose a set of kinases and transcription factors that can mediate the action of AKT1 on the deregulated transcripts and proteins. Taken altogether, our results provide a resource of direct and indirect AKT1 targets in granulosa cells and may help understand its roles in this ovarian cell type.

Akt inhibitor SC66 promotes cell sensitivity to cisplatin in chemoresistant ovarian cancer cells through inhibition of COL11A1 expression

We studied Akt inhibition using SC66 in a NOD-SCID xenograft mouse model and a panel of eight ovarian cancer cell lines. Elevated phospho-Akt levels in cancerous tissue were associated with short progression-free survival and overall survival. Cell sensitivity to SC66 was inversely correlated with phospho-Akt and COL11A1 expression levels, as well as resistance to cisplatin or paclitaxel. SC66 inhibited phosphorylation of Akt and its downstream effectors 4EBP1 and p70S6 kinase. SC66 also attenuated expression of TWIST1 and Mcl-1, factors important in cell invasiveness and anti-apoptosis, respectively. SC66-sensitized chemoresistant cells to cisplatin and paclitaxel treatment, and promoted apoptosis. In addition, SC66 inhibited COL11A1 expression via decreased binding of CCAAT/enhancer-binding protein beta (c/EBPβ), reducing chemoresistance and decreasing binding of nuclear transcription factor Y (NF-YA) to COL11A1. A mouse xenograft experiment demonstrated that SC66 treatment caused a reduction in tumor formation and enhanced the therapeutic efficacy of cisplatin. This study demonstrates the role of Akt in ovarian tumor progression and chemoresistance, and supports the application of SC66 as a therapy for ovarian cancer.

Androgens Induce Invasiveness of Triple Negative Breast Cancer Cells Through AR/Src/PI3-K Complex Assembly

Breast cancer (BC) is still characterized by high morbidity and mortality. A specific BC subtype named triple negative BC (TNBC) lacks estrogen and progesterone receptors (ER and PR, respectively) and is characterized by the absence of overexpression/amplification of human epidermal growth factor receptor 2 (HER2). The androgen receptor (AR) is expressed in TNBC, although its function in these cancers is still debated. Moreover, few therapeutic options are currently available for the treatment of TNBC. In this study, we have used TNBC-derived MDA-MB231 and MDA-MB453 cells that, albeit at different extent, both express AR. Androgen challenging induces migration and invasiveness of these cells. Use of the anti-androgen bicalutamide or AR knockdown experiments show that these effects depend on AR. Furthermore, the small peptide, S1, which mimics the AR proline-rich motif responsible for the interaction of AR with SH3-Src, reverses the effects in both cell lines, suggesting that the assembly of a complex made up of AR and Src drives the androgen-induced motility and invasiveness. Co-immunoprecipitation experiments in androgen-treated MDA-MB231 and MDA-MB453 cells show that the AR/Src complex recruits p85α, the regulatory subunit of PI3-K. In such a way, the basic machinery leading to migration and invasiveness is turned-on. The S1 peptide inhibits motility and invasiveness of TNBC cells and disrupts the AR/Src/p85α complex assembly in MDA-MB231 cells. This study shows that the rapid androgen activation of Src/PI3-K signaling drives migration and invasiveness of TNBC cells and suggests that the S1 peptide is a promising therapeutic option for these cancers.

Modulation of CD44, EGFR and RAC Pathway Genes (WAVE Complex) in Epithelial Cancers

Cancer hallmarks help in understanding the diversity of various neoplasms. Epithelial cancers play an immense role in the tumor biology through Epithelial-Mesenchymal Transition (EMT) process. Receptor tyrosine kinase, as well as phosphatidyl ionositol-3 kinase pathways, play an important role in the regulation of cell proliferation, survival, and differentiation during EMT. Till date, numerous studies have shown modulation in the expression profile of potential targets like CD44, EGFR, and Rac in epithelial cancers. CD44 interacts with EGFR and recruits other molecules which further activate the Rac pathway intermediates. This review mainly focused on modulation of genes like CD44, EGFR, and Rac pathway intermediates which play a crucial role in the tumor progression, metastasis, proliferation, and invasion characteristics in epithelial cancers with EMT properties. Hence, targeting Rac pathway might be a more strategically relevant approach in treating epithelial cancers.

AKT as a Therapeutic Target for Cancer

Many cellular processes in cancer are attributed to kinase signaling networks. V-akt murine thymoma viral oncogene homolog (AKT) plays a major role in the PI3K/AKT signaling pathways. AKT is activated by PI3K or phosphoinositide-dependent kinases (PDK) as well as growth factors, inflammation, and DNA damage. Signal transduction occurs through downstream effectors such as mTOR, glycogen synthase kinase 3 beta (GSK3β), or forkhead box protein O1 (FOXO1). The abnormal overexpression or activation of AKT has been observed in many cancers, including ovarian, lung, and pancreatic cancers, and is associated with increased cancer cell proliferation and survival. Therefore, targeting AKT could provide an important approach for cancer prevention and therapy. In this review, we discuss the rationale for targeting AKT and also provide details regarding synthetic and natural AKT-targeting compounds and their associated studies.

CD81 Promotes a Migratory Phenotype in Neuronal-Like Cells

Tetraspanins, such as CD81, can form lateral associations with each other and with other transmembrane proteins. These interactions may underlie CD81 functions in multiple cellular processes, such as adhesion, morphology, migration, and differentiation. Since CD81's role in neuronal cells' migration has not been established, we here evaluated effects of CD81 on the migratory phenotype of SH-SY5Y neuroblastoma cells. CD81 was found enriched at SH-SY5Y cell's membrane, co-localizing with its interactor filamentous-actin (F-actin) in migratory relevant structures of the leading edge (filopodia, stress fibers, and adhesion sites). CD81 overexpression increased the number of cells with a migratory phenotype, in a potentially phosphatidylinositol 3 kinase (PI3K)-Ak strain transforming (AKT) mediated manner. Indeed, CD81 also co-localized with AKT, a CD81-interactor and actin remodeling agent, at the inner leaflet of the plasma membrane. Pharmacologic inhibition of PI3K, the canonical AKT activator, led both to a decrease in the acquisition of a migratory phenotype and to a redistribution of intracellular CD81 and F-actin into cytoplasmic agglomerates. These findings suggest that in neuronal-like cells CD81 bridges active AKT and actin, promoting the actin remodeling that leads to a motile cell morphology. Further studies on this CD81-mediated mechanism will improve our knowledge on important physiological and pathological processes such as cell migration and differentiation, and tumor metastasis.

Human Brain Endothelial CXCR2 is Inflammation-Inducible and Mediates CXCL5- and CXCL8-Triggered Paraendothelial Barrier Breakdown

Chemokines (C-X-C) motif ligand (CXCL) 5 and 8 are overexpressed in patients with multiple sclerosis, where CXCL5 serum levels were shown to correlate with blood–brain barrier dysfunction as evidenced by gadolinium-enhanced magnetic resonance imaging. Here, we studied the potential role of CXCL5/CXCL8 receptor 2 (CXCR2) as a regulator of paraendothelial brain barrier function, using the well-characterized human cerebral microvascular endothelial cell line hCMEC/D3. Low basal CXCR2 mRNA and protein expression levels in hCMEC/D3 were found to strongly increase under inflammatory conditions. Correspondingly, immunohistochemistry of brain biopsies from two patients with active multiple sclerosis revealed upregulation of endothelial CXCR2 compared to healthy control tissue. Recombinant CXCL5 or CXCL8 rapidly and transiently activated Akt/protein kinase B in hCMEC/D3. This was followed by a redistribution of tight junction-associated protein zonula occludens-1 (ZO-1) and by the formation of actin stress fibers. Functionally, these morphological changes corresponded to a decrease of paracellular barrier function, as measured by a real-time electrical impedance-sensing system. Importantly, preincubation with the selective CXCR2 antagonist SB332235 partially prevented chemokine-induced disturbance of both tight junction morphology and function. We conclude that human brain endothelial CXCR2 may contribute to blood–brain barrier disturbance under inflammatory conditions with increased CXCL5 and CXCL8 expression, where CXCR2 may also represent a novel pharmacological target for blood–brain barrier stabilization.

Oncogenicitiy Comparison of Human Papillomavirus Type 52 E6 Variants

Human papillomavirus (HPV) infection contributes to virtually all cases of cervical cancer, the fourth most common cancer affecting women worldwide. The oncogenicity of HPV is mainly attributable to the E6 and E7 oncoproteins. HPV-52 is the seventh most common HPV type globally, but it has a remarkably high prevalence in East Asia. In previous studies it has been speculated that the oncogenicity might vary among different HPV-52 variants. In the present study, we compared the oncogenicity of E6 derived from the HPV-52 prototype and three commonly found variants, V1 (K93R), V2 (E14D/V92L) and V3 (K93R/N122K), through molecular and phenotypic approaches. We demonstrated that cells containing V1 achieved higher colony formation and showed greater cell migration ability when compared to other variants, but no difference in cell immortalization ability was observed. At the molecular level, the three variants formed complexes with E6-associated protein (E6AP) and p53 as efficiently as the prototype. They degraded p53 and PSD95/Dlg/ZO-1(PDZ) proteins, including MAGI-1c and Dlg, to a similar extent. They also exhibited a similar subcellular localization, and shared a half-life of approximately 45 min. Our findings provide a clearer picture of HPV-52 E6 variant oncogenicity, which is important for further studies aiming to understand the unusually high prevalence of HPV-52 among cervical cancers in East Asia.

Elevated leptin disrupts epithelial polarity and promotes premalignant alterations in the mammary gland

Obesity is a highly prevalent and modifiable breast cancer risk factor. While the role of obesity in fueling breast cancer progression is well established, the mechanisms linking obesity to breast cancer initiation are poorly understood. A hallmark of breast cancer initiation is the disruption of apical polarity in mammary glands. Here we show that mice with diet-induced obesity display mislocalization of Par3, a regulator of cellular junctional complexes defining mammary epithelial polarity. We found that epithelial polarity loss also occurs in a 3D coculture system that combines acini with human mammary adipose tissue, and establish that a paracrine effect of the tissue adipokine leptin causes loss of polarity by overactivation of the PI3K/Akt pathway. Leptin sensitizes non-neoplastic cells to proliferative stimuli, causes mitotic spindle misalignment, and expands the pool of cells with stem/progenitor characteristics, which are early steps for cancer initiation. We also found that normal breast tissue samples with high leptin/adiponectin transcript ratio characteristic of obesity have an altered distribution of apical polarity markers. This effect is associated with increased epithelial cell layers. Our results provide a molecular basis for early alterations in epithelial architecture during obesity-mediated cancer initiation.

Apelin receptor (Aplnr) signaling promotes fibroblast migration

Cell migration is one of the major cellular processes in development, tissue regeneration, wound healing, cancer and immune function. Underlying molecular mechanism behind the fibroblast cell migration and matrix interactions generates the basis of tissue homeostasis. The role of Apelin receptor (Aplnr) signaling in gastrulation movements has emerged in recent years but how Aplnr regulates cell movement remains unclear. In the current study, the migratory activity of Aplnr signaling has been shown in cultured fibroblast cells in vitro by scratch assay, gene and protein expression analyses. Aplnr signaling was activated and knocked down in MEFs and NIH-3T3 mouse fibroblast cells to analyze whether cell migration is affected by Aplnr signalling. Activation of Aplnr signaling by Apelin peptide and small molecule ML-233 increased cell movement and expression of migration related gene and proteins including Actin and Vimentin. Similarly, reducing the expression of Aplnr and Apelin (Apln) by siRNA exposure inhibited cell migration of mouse fibroblast cells. Application of Apelin peptide and small molecule ML-233 to human fibroblast cells enhanced scratch closure rate significantly compared to control. This study demonstrated that activation of Aplnr signaling promotes cell migration of fibroblast cells in vitro. Aplnr signaling could be a potential therapeutic candidate as a migration related regulatory mechanism in cancer and wound healing for further research.

The signaling pathways that mediate the anti-cancer effects of caloric restriction

Caloric restriction (CR) has been shown to promote longevity and ameliorate aging-associated diseases, including cancer. Extensive research over recent decades has revealed that CR reduces IGF-1/PI3K/AKT signaling and increases sirtuin signaling. We recently found that CR also enhances ALDOA/DNA-PK/p53 signaling. In the present review, we summarize the molecular mechanisms underlying the modulation of the IGF-1/PI3K/AKT pathway, sirtuin signaling, and the ALDOA/DNA-PK/p53 pathway by CR. We also summarize the evidence concerning the roles of these signaling pathways in carcinogenesis, and discuss how they are regulated by CR. Finally, we discuss the crosstalk between these signaling pathways.

Fibroblast growth factor improves the motility of human mesenchymal stem cells expanded in a human plasma-derived xeno-free medium through αVβ3 integrin

Human mesenchymal stem cells (MSC) are being explored for cell therapies targeting varied human diseases. For that, cells are being expanded in vitro, many times with fetal bovine serum (FBS) as the main source of growth factors. However, animal-derived components should not be used, to avoid immune rejection from the patient that receives the MSC. To solve this issue, different xeno-free media are being developed, and an industrial-grade human plasma fraction (SCC) is a promising candidate to substitute FBS. Indeed, we have previously shown that MSC expanded in SCC-medium maintain their phenotype and genetic stability. However, a reduction on MSC motility was observed when comparing with MSC motility on FBS-medium. Thus, in this present study, we have tested different factors to improve the motility of MSC in SCC-medium. Time lapse assays and experiments with transwells revealed that supplementation of the xeno-free medium with FGF or PDGF, but not TNF-α or SDF-1, increased MSC motility. Interestingly, FGF and PDGF supplementation also led to alterations on MSC morphology to a shape similar to the one observed when using FBS. The mechanism behind the effect of FGF on MSC motility involved the increased expression of αVβ3 integrin. Furthermore, assays with small molecule inhibitors revealed that the signalling molecule p38 MAPK is important for MSC motility and that MEK/ERK and PI3K/AKT also have a role on FGF-supplemented expanded MSC. Thus, it was found that FGF supplementation can improve the motility of xeno-free-expanded MSC and that the cells motility is regulated by αVβ3 integrin.

Topographically Defined, Biodegradable Nanopatterned Patches to Regulate Cell Fate and Acceleration of Bone Regeneration

If only allowed to proceed naturally, the bone-healing process can take several weeks, months, or even years depending on the injury size. In terms of bone-healing speed, many studies have been conducted investigating the deliverance of various growth factors of implantable biomaterials to shorten the time for bone regeneration. However, there may be side effects such as nerve pain, infection, or ectopic bone formation. As an alternative method, we focused on biophysical guidance, which provided similar topographical cues to the cellular environment to recruit host cells for bone defect healing. In this study, we hypothesized that aligned nanotopographical features have enhanced osteoblast recruitment, migration, and differentiation without external stimuli. We designed and fabricated a biodegradable poly(lactic- co-glycolic acid) nanopatterned patch using simple solvent casting and capillary force lithography. We confirmed that a biodegradable nanopatterned patch (BNP) accelerated the migration of osteoblasts according to the orientation of the patterned direction. These highly aligned osteoblasts may contribute to in vitro osteogenic differentiation, such as alkaline phosphate activity, mineralization, and calcium deposition, compared to the biodegradable flat patch (BFP). To demonstrate bone defect healing by BNP guidance in vivo, we implanted either whole or bridge BNP on the critical size defect of mouse calvarial ( ø 4 mm) or tibia bone (3 × 7 mm²). Only the BNP-treated group showed faster new bone formation and compact bone regeneration at the calvarial or tibia bone defect area compared to BFP at 4 or 8 weeks. Bridge BNP guided, in particular, the regeneration of new bone formation along the parallel direction of nanopatterned substrates. Here, we show that a BNP with biophysical guidance should be suitable for use in bone tissue regeneration through accelerated migration of the intact host cell.

Disruption of C1galt1 Gene Promotes Development and Metastasis of Pancreatic Adenocarcinomas in Mice

BACKGROUND & AIMS

Pancreatic ductal adenocarcinomas (PDACs) produce higher levels of truncated O-glycan structures (such as Tn and sTn) than normal pancreata. Dysregulated activity of core 1 synthase glycoprotein-N-acetylgalactosamine 3-β-galactosyltransferase 1 (C1GALT1) leads to increased expression of these truncated O-glycans. We investigated whether and how truncated O-glycans contributes to the development and progression of PDAC using mice with disruption of C1galt1.

METHODS

We crossed C1galt1 floxed mice (C1galt1^loxP/loxP) with Kras^G12D/+; Trp53^R172H/+; Pdx1-Cre (KPC) mice to create KPCC mice. Growth and progression of pancreatic tumors were compared between KPC and KPCC mice; pancreatic tissues were collected and analyzed by immunohistochemistry; immunofluorescence; and Sirius red, alcian blue, and lectin staining. We used the CRISPR/Cas9 system to disrupt C1GALT1 in human PDAC cells (T3M4 and CD18/HPAF) and levels of O-glycans were analyzed by lectin blotting, mass spectrometry, and lectin pulldown assay. Orthotopic studies and RNA sequencing analyses were performed with control and C1GALT1 knockout PDAC cells. C1GALT1 expression was analyzed in well-differentiated (n = 36) and poorly differentiated (n = 23) PDAC samples by immunohistochemistry.

RESULTS

KPCC mice had significantly shorter survival times (median 102 days) than KPC mice (median 200 days) and developed early pancreatic intraepithelial neoplasias at 3 weeks, PDAC at 5 weeks, and metastasis at 10 weeks compared with KPC mice. Pancreatic tumors that developed in KPCC mice were more aggressive (more invasive and metastases) than those in KPC mice, had a decreased amount of stroma, and had increased production of Tn. Poorly differentiated PDAC specimens had significantly lower levels of C1GALT1 than well-differentiated PDACs. Human PDAC cells with knockout of C1GALT1 had aberrant glycosylation of MUC16 compared with control cells and increased expression of genes that regulate tumorigenesis and metastasis.

CONCLUSIONS

In studies of KPC mice with disruption of C1galt1, we found that loss of C1galt1 promotes development of aggressive PDACs and increased metastasis. Knockout of C1galt1 leads to increased tumorigenicity and truncation of O-glycosylation on MUC16, which could contribute to increased aggressiveness.

Cell chirality regulates intercellular junctions and endothelial permeability

Cell chirality is a newly discovered intrinsic property of the cell, reflecting the bias of the cell to polarize in the left-right axis. Despite increasing evidence on its substantial role in the asymmetric development of embryos, little is known about implications of cell chirality in physiology and disease. We demonstrate that cell chirality accounts for the nonmonotonic, dose-response relationship between endothelial permeability and protein kinase C (PKC) activation. The permeability of the endothelial cell layer is tightly controlled in our body, and dysregulation often leads to tissue inflammation and diseases. Our results show that low-level PKC activation is sufficient to reverse cell chirality through phosphatidylinositol 3-kinase/AKT signaling and alters junctional protein organization between cells with opposite chirality, leading to an unexpected substantial change in endothelial permeability. Our findings suggest that cell chirality regulates intercellular junctions in important ways, providing new opportunities for drug delivery across tightly connected semipermeable cellular sheets.

Oxidative stress-modulating drugs have preferential anticancer effects - involving the regulation of apoptosis, DNA damage, endoplasmic reticulum stress, autophagy, metabolism, and migration

To achieve preferential effects against cancer cells but less damage to normal cells is one of the main challenges of cancer research. In this review, we explore the roles and relationships of oxidative stress-mediated apoptosis, DNA damage, ER stress, autophagy, metabolism, and migration of ROS-modulating anticancer drugs. Understanding preferential anticancer effects in more detail will improve chemotherapeutic approaches that are based on ROS-modulating drugs in cancer treatments.

Death receptor 6 promotes ovarian cancer cell migration through KIF11

The expression of death receptor 6 (DR6) is abnormal in some cancer types, but the function and underlying molecular mechanisms of DR6 in tumor progression are not yet clear. In the present study, our analysis of ovarian cancer RNA sequencing data from The Cancer Genome Atlas revealed that DR6 is upregulated in human ovarian cancer. We confirmed that the expression level of DR6 is upregulated in ovarian cancer tissues when compared with matched adjacent normal tissues. In addition, DR6 enhanced ovarian carcinoma cell migration ability, and decreased expression of DR6 inhibited the expression of matrix metalloprotease (MMP) 2 and MMP9, and increased the expression of E‐cadherin. Additionally, DR6 shRNA caused a significant decrease in phosphoinositide‐3‐kinase (PI3K), phospho (p) ‐AKT, p‐extracellular signal‐regulated kinase (ERK), and p‐mitogen‐activated protein kinase kinase expression in SKOV3 cells. These results suggested that DR6 can enhance ovarian carcinoma cell migration ability through the mitogen‐activated protein kinase/ERK and PI3K/AKT pathways. Notably, mass spectrometric analysis indicated that DR6 co‐purified with kinesin family member 11 (KIF11), and we verified the interaction between KIF11 and DR6 by co‐immunoprecipitation and glutathione S‐transferase pull‐down. Furthermore, we demonstrated that DR6 can bind tumor necrosis factor receptor‐associated factor 4 (TRAF4) with co‐immunoprecipitation. Overexpression of KIF11 or TRAF4 eliminated the suppression of carcinoma cell migration by DR6 knockdown. We also found that TRAF4 and KIF11 were upregulated in ovarian carcinomas and that their level of expression was positively correlated with that of DR6. The findings above suggest that DR6 may play a notable oncogenic role in ovarian malignancy by interacting with TRAF4 and KIF11, and that DR6 may be an effective therapeutic target in ovarian cancer.

Reversine inhibits Colon Carcinoma Cell Migration by Targeting JNK1

Colorectal cancer is one of the most commonly diagnosed cancers and the third most common cause of cancer-related death. Metastasis is the leading reason for the resultant mortality of these patients. Accordingly, development and characterization of novel anti-cancer drugs limiting colorectal tumor cell dissemination and metastasis are needed. In this study, we found that the small molecule Reversine reduces the migration potential of human colon carcinoma cells in vitro. A coupled kinase assay with bio-informatics approach identified the c-Jun N-terminal kinase (JNK) cascade as the main pathway inhibited by Reversine. Knockdown experiments and pharmacological inhibition identified JNK1 but not JNK2, as a downstream effector target in cancer cell migration. Xenograft experiments confirm the effect of JNK inhibition in the metastatic potential of colon cancer cells. These results highlight the impact of individual JNK isoforms in cancer cell metastasis and propose Reversine as a novel anti-cancer molecule for treatment of colon cancer patients.

Novel role of Giα2 in cell migration: Downstream of PI3-kinase-AKT and Rac1 in prostate cancer cells

Tumor cell motility is the essential step in cancer metastasis. Previously, we showed that oxytocin and epidermal growth factor (EGF) effects on cell migration in prostate cancer cells require Giα2 protein. In the current study, we investigated the interactions among G-protein coupled receptor (GPCR), Giα2, PI3-kinase, and Rac1 activation in the induction of migratory and invasive behavior by diverse stimuli. Knockdown and knockout of endogenous Giα2 in PC3 cells resulted in attenuation of transforming growth factor β1 (TGFβ1), oxytocin, SDF-1α, and EGF effects on cell migration and invasion. In addition, knockdown of Giα2 in E006AA cells attenuated cell migration and overexpression of Giα2 in LNCaP cells caused significant increase in basal and EGF-stimulated cell migration. Pretreatment of PC3 cells with Pertussis toxin resulted in attenuation of TGFβ1- and oxytocin-induced migratory behavior and PI3-kinase activation without affecting EGF-induced PI3-kinase activation and cell migration. Basal- and EGF-induced activation of Rac1 in PC3 and DU145 cells were not affected in cells after Giα2 knockdown. On the other hand, Giα2 knockdown abolished the migratory capability of PC3 cells overexpressing constitutively active Rac1. The knockdown or knockout of Giα2 resulted in impaired formation of lamellipodia at the leading edge of the migrating cells. We conclude that Giα2 protein acts at two different levels which are both dependent and independent of GPCR signaling to induce cell migration and invasion in prostate cancer cells and its action is downstream of PI3-kinase-AKT-Rac1 axis.

The Drosophila insulin pathway controls Profilin expression and dynamic actin-rich protrusions during collective cell migration

Understanding how different cell types acquire their motile behaviour is central to many normal and pathological processes. Drosophila border cells represent a powerful model for addressing this issue and to specifically decipher the mechanisms controlling collective cell migration. Here, we identify the Drosophila Insulin/Insulin-like growth factor signalling (IIS) pathway as a key regulator in controlling actin dynamics in border cells, independently of its function in growth control. Loss of IIS activity blocks the formation of actin-rich long cellular extensions that are important for the delamination and the migration of the invasive cluster. We show that IIS specifically activates the expression of the actin regulator chickadee, the Drosophila homolog of Profilin, which is essential for promoting the formation of actin extensions and migration through the egg chamber. In this process, the transcription factor FoxO acts as a repressor of chickadee expression. Altogether, these results show that local activation of IIS controls collective cell migration through regulation of actin homeostasis and protrusion dynamics.

Human Plasmablast Migration Toward CXCL12 Requires Glucose Oxidation by Enhanced Pyruvate Dehydrogenase Activity via AKT

Migration of human plasmablast to the bone marrow is essential for the final differentiation of plasma cells and maintenance of effective humoral immunity. This migration is controlled by CXCL12/CXCR4-mediated activation of the protein kinase AKT. Herein, we show that the CXCL12-induced migration of human plasmablasts is dependent on glucose oxidation. Glucose depletion markedly inhibited plasmablast migration by 67%, and the glucose analog 2-deoxyglucose (2-DG) reduced the migration by 53%; conversely, glutamine depletion did not reduce the migration. CXCL12 boosted the oxygen consumption rate (OCR), and 2-DG treatment significantly reduced the levels of all measured tricarboxylic acid (TCA) cycle intermediates. AKT inhibitors blocked the CXCL12-mediated increase of OCR. CXCL12 enhanced the pyruvate dehydrogenase (PDH) activity by 13.5-fold in an AKT-dependent manner to promote mitochondrial oxidative phosphorylation. The knockdown and inhibition of PDH confirmed its indispensable role in CXCL12-induced migration. Cellular ATP levels fell by 91% upon exposure to 2-DG, and the mitochondrial ATP synthase inhibitor oligomycin inhibited CXCL12-induced migration by 85%. Low ATP levels inhibited the CXCL12-induced activation of AKT and phosphorylation of myosin light chains by 42%, which are required for cell migration. Thus, we have identified a mechanism that controls glucose oxidation via AKT signaling and PDH activation, which supports the migration of plasmablasts. This mechanism can provide insights into the proper development of long-lived plasma cells and is, therefore, essential for optimal humoral immunity. To our knowledge, this study is the first to investigate metabolic mechanisms underlying human plasmablast migration toward CXCL12.

Mechanism of metastasis suppression by luteolin in breast cancer

Metastatic breast cancer is typically an extremely aggressive cancer with poor prognosis. Metastasis requires the orchestration of homeostatic factors and cellular programs, many of which are potential therapeutic targets. Luteolin (2-[3,4-dihydroxyphenyl]-5,7-dihydroxy-4-chromenone), is a naturally occurring flavonoid found in fruits and vegetables that exhibits many anticancer properties. Luteolin obstructs metastasis through both direct and indirect mechanisms. For instance, luteolin may suppress breast cancer invasion by acting as an antiangiogenic therapeutic inhibiting VEGF production and its receptor’s activity. Furthermore, luteolin decreases epithelial–mesenchymal transition markers and metastatic proclivity. Luteolin also acts as an antiproliferative by suppressing receptor tyrosine-kinase activity and apoptosis, both of which could prevent incipient colonization of breast cancer. Many of these antimetastatic characteristics accredited to luteolin are likely functionally related. For instance, the PI3K/Akt pathway, which is impeded by luteolin, has several downstream programs involved in increased proliferation, survival, and metastatic potential in breast cancer. In this review, luteolin’s ability to ameliorate breast cancer is summarized. The paper also offers insight into the molecular mechanisms by which luteolin may suppress breast cancer metastasis.

RECK isoforms have opposing effects on cell migration

Cell migration is a highly conserved process involving cytoskeletal reorganization and restructuring of the surrounding extracellular matrix. Although there are many studies describing mechanisms underlying cell motility, little has been reported about the contribution of alternative isoform use toward cell migration. Here, we investigated whether alternative isoform use can affect cell migration focusing on reversion-inducing-cysteine-rich protein with Kazal motifs (RECK), an established inhibitor of cell migration. We found that a shorter isoform of RECK is more highly expressed in proliferating fibroblasts, in TGF-β-treated fibroblasts, and in tumors compared with differentiated tissue. Knockdown of this short RECK isoform reduces fibroblast migration through Matrigel. Thus, this short isoform of RECK generated by a combination of alternative splicing and alternative polyadenylation plays an opposing role to the canonical RECK isoform, as knockdown of canonical RECK results in faster cell migration through Matrigel. We show that the short RECK protein competes with matrix metalloprotease 9 (MMP9) for binding to the Kazal motifs of canonical RECK, thus liberating MMP9 from an inactivating interaction with canonical RECK. Our studies provide a new paradigm and a detailed mechanism for how alternative isoform use can regulate cell migration by producing two proteins with opposing effects from the same genetic locus.

Who does TORC2 talk to?

The target of rapamycin (TOR) is a protein kinase that, by forming complexes with partner proteins, governs diverse cellular signalling networks to regulate a wide range of processes. TOR thus plays central roles in maintaining normal cellular functions and, when dysregulated, in diverse diseases. TOR forms two distinct types of multiprotein complexes (TOR complexes 1 and 2, TORC1 and TORC2). TORC1 and TORC2 differ in their composition, their control and their substrates, so that they play quite distinct roles in cellular physiology. Much effort has been focused on deciphering the detailed regulatory links within the TOR pathways and the structure and control of TOR complexes. In this review, we summarize recent advances in understanding mammalian (m) TORC2, its structure, its regulation, and its substrates, which link TORC2 signalling to the control of cell functions. It is now clear that TORC2 regulates several aspects of cell metabolism, including lipogenesis and glucose transport. It also regulates gene transcription, the cytoskeleton, and the activity of a subset of other protein kinases.

Anticancer Activity of Euplotin C, Isolated from the Marine Ciliate Euplotes crassus, Against Human Melanoma Cells

Cutaneous melanoma is the most serious type of skin cancer, so new cytotoxic weapons against novel targets in melanoma are of great interest. Euplotin C (EC), a cytotoxic secondary metabolite of the marine ciliate Euplotes crassus, was evaluated in the present study on human cutaneous melanoma cells to explore its anti-melanoma activity and to gain more insight into its mechanism of action. EC exerted a marked cytotoxic effect against three different human melanoma cell lines (A375, 501Mel and MeWo) with a potency about 30-fold higher than that observed in non-cancer cells (HDFa cells). A pro-apoptotic activity and a decrease in melanoma cell migration by EC were also observed. At the molecular level, the inhibition of the Erk and Akt pathways, which control many aspects of melanoma aggressiveness, was shown. EC cytotoxicity was antagonized by dantrolene, a ryanodine receptor (RyR) antagonist, in a concentration-dependent manner. A role of RyR as a direct target of EC was also suggested by molecular modelling studies. In conclusion, our data provide the first evidence of the anti-melanoma activity of EC, suggesting it may be a promising new scaffold for the development of selective activators of RyR to be used for the treatment of melanoma and other cancer types.

Telocinobufagin inhibits the epithelial-mesenchymal transition of breast cancer cells through the phosphoinositide 3-kinase/protein kinase B/extracellular signal-regulated kinase/Snail signaling pathway

Telocinobufagin (TBG), an active ingredient of Venenumbufonis, exhibits an immunomodulatory activity. However, its antimetastatic activity in breast cancer remains unknown. The present study investigated whether TBG prevents breast cancer metastasis and evaluated its regulatory mechanism. TBG inhibited the migration and invasion of 4T1 breast cancer cells. Furthermore, TBG triggered the collapse of F-actin filaments in breast cancer. The epithelial-mesenchymal transition (EMT) markers, vimentin and fibronectin, were downregulated following TBG treatment. However, E-cadherin was upregulated following TBG treatment. Snail, a crucial transcriptional factor of EMT, was downregulated following TBG treatment. Signaling pathway markers, including phosphorylated protein kinase B (P-Akt), p-mechanistic target of rapamycin (mTOR) and p-extracellular signal-regulated kinase (ERK), were decreased following TBG treatment. The same results were obtained from in vivo experiments. In conclusion, in vitro and in vivo experiments reveal that TBG inhibited migration, invasion and EMT via the phosphoinositide 3-kinase (PI3K)/Akt/ERK/Snail signaling pathway in breast cancer.

Alternagin-C binding to α2β1 integrin controls matrix metalloprotease-9 and matrix metalloprotease-2 in breast tumor cells and endothelial cells

Background

Matrix metalloproteinases (MMPs) are key players in tumor progression, helping tumor cells to modify their microenvironment, which allows cell migration to secondary sites. The role of integrins, adhesion receptors that connect cells to the extracellular matrix, in MMP expression and activity has been previously suggested. However, the mechanisms by which integrins control MMP expression are not completely understood. Particularly, the role of α2β1 integrin, one of the major collagen I receptors, in MMP activity and expression has not been studied. Alternagin-C (ALT-C), a glutamate-cysteine-aspartate-disintegrin from Bothrops alternatus venom, has high affinity for an α2β1 integrin. Herein, we used ALT-C as a α2β1 integrin ligand to study the effect of ALT-C on MMP-9 and MMP-2 expression as well as on tumor cells, fibroblats and endothelial cell migration.

Methods

ALT-C was purified by two steps of gel filtration followed by anion exchange chromatography. The α₂β₁ integrin binding properties of ALT-C, its dissociation constant (K_d) relative to this integrin and to collagen I (Col I) were determined by surface plasmon resonance. The effects of ALT-C (10, 40, 100 and 1000 nM) in migration assays were studied using three human cell lines: human fibroblasts, breast tumor cell line MDA-MB-231, and microvascular endothelial cells HMEC-1, considering cells found in the tumor microenvironment. ALT-C effects on MMP-9 and MMP-2 expression and activity were analyzed by quantitative PCR and gelatin zymography, respectively. Focal adhesion kinase activation was determined by western blotting.

Results

Our data demonstrate that ALT-C, after binding to α₂β₁ integrin, acts by two distinct mechanisms against tumor progression, depending on the cell type: in tumor cells, ALT-C decreases MMP-9 and MMP-2 contents and activity, but increases focal adhesion kinase phosphorylation and transmigration; and in endothelial cells, ALT-C inhibits MMP-2, which is necessary for tumor angiogenesis. ALT-C also upregulates c-Myc mRNA level, which is related to tumor suppression.

Conclusion

These results demonstrate that α₂β₁ integrin controls MMP expression and reveal this integrin as a target for the development of antiangiogenic and antimetastatic therapies.

Electronic supplementary material

The online version of this article (10.1186/s40409-018-0150-2) contains supplementary material, which is available to authorized users.

EphA3 maintains radioresistance in head and neck cancers through epithelial mesenchymal transition

Radiotherapy is a well-established therapeutic modality used in the treatment of many cancers. However, radioresistance remains a serious obstacle to successful treatment. Radioresistance can cause local recurrence and distant metastases in some patients after radiation treatment. Thus, many studies have attempted to identify effective radiosensitizers. Eph receptor functions contribute to tumor development, modulating cell-cell adhesion, invasion, neo-angiogenesis, tumor growth and metastasis. However, the role of EphA3 in radioresistance remains unclear. In the current study, we established a stable radioresistant head and neck cancer cell line (AMC HN3R cell line) and found that EphA3 was expressed predominantly in the radioresistant head and neck cancer cell line through DNA microarray, real time PCR and Western blotting. Additionally, we found that EphA3 was overexpressed in recurrent laryngeal cancer specimens after radiation therapy. EphA3 mediated the tumor invasiveness and migration in radioresistant head and neck cancer cell lines and epithelial mesenchymal transition- related protein expression. Inhibition of EphA3 enhanced radiosensitivity in the AMC HN 3R cell line in vitro and in vivo study. In conclusion, our results suggest that EphA3 is overexpressed in radioresistant head and neck cancer and plays a crucial role in the development of radioresistance in head and neck cancers by regulating the epithelial mesenchymal transition pathway.

N-glycosylation by N-acetylglucosaminyltransferase V enhances the interaction of CD147/basigin with integrin β1 and promotes HCC metastasis

While the importance of protein N-glycosylation in cancer cell migration is well appreciated, the precise mechanisms by which N-acetylglucosaminyltransferase V (GnT-V) regulates cancer processes remain largely unknown. In the current study, we report that GnT-V-mediated N-glycosylation of CD147/basigin, a tumor-associated glycoprotein that carries β1,6-N-acetylglucosamine (β1,6-GlcNAc) glycans, is upregulated during TGF-β1-induced epithelial-to-mesenchymal transition (EMT), which correlates with tumor metastasis in patients with hepatocellular carcinoma (HCC). Interruption of β1,6-GlcNAc glycan modification of CD147/basigin decreased matrix metalloproteinase (MMP) expression in HCC cell lines and affected the interaction of CD147/basigin with integrin β1. These results reveal that β1,6-branched glycans modulate the biological function of CD147/basigin in HCC metastasis. Moreover, we showed that the PI3K/Akt pathway regulates GnT-V expression and that inhibition of GnT-V-mediated N-glycosylation suppressed PI3K signaling. In summary, β1,6-branched N-glycosylation affects the biological function of CD147/basigin and these findings provide a novel approach for the development of therapeutic strategies targeting metastasis. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

AKT-ions with a TWIST between EMT and MET

The transcription factor Twist is an important regulator of cranial suture during embryogenesis. Closure of the neural tube is achieved via Twist-triggered cellular transition from an epithelial to mesenchymal phenotype, a process known as epithelial-mesenchymal transition (EMT), characterized by a remarkable increase in cell motility. In the absence of Twist activity, EMT and associated phenotypic changes in cell morphology and motility can also be induced, albeit moderately, by other transcription factor families, including Snail and Zeb. Aberrant EMT triggered by Twist in human mammary tumour cells was first reported to drive metastasis to the lung in a metastatic breast cancer model. Subsequent analysis of many types of carcinoma demonstrated overexpression of these unique EMT transcription factors, which statistically correlated with worse outcome, indicating their potential as biomarkers in the clinic. However, the mechanisms underlying their activation remain unclear. Interestingly, increasing evidence indicates they are selectively activated by distinct intracellular kinases, thereby acting as downstream effectors facilitating transduction of cytoplasmic signals into nucleus and reprogramming EMT and mesenchymal-epithelial transition (MET) transcription to control cell plasticity. Understanding these relationships and emerging data indicating differential phosphorylation of Twist leads to complex and even paradoxical functionalities, will be vital to unlocking their potential in clinical settings.

α5β1 integrin trafficking and Rac activation are regulated by APPL1 in a Rab5-dependent manner to inhibit cell migration

Cell migration is a tightly coordinated process that requires the spatiotemporal regulation of many molecular components. Because adaptor proteins can serve as integrators of cellular events, they are being increasingly studied as regulators of cell migration. The adaptor protein containing a pleckstrin-homology (PH) domain, phosphotyrosine binding (PTB) domain, and leucine zipper motif 1 (APPL1) is a 709 amino acid endosomal protein that plays a role in cell proliferation and survival as well as endosomal trafficking and signaling. However, its function in regulating cell migration is poorly understood. Here, we show that APPL1 hinders cell migration by modulating both trafficking and signaling events controlled by Rab5 in cancer cells. APPL1 decreases internalization and increases recycling of α5β1 integrin, leading to higher levels of α5β1 integrin at the cell surface that hinder adhesion dynamics. Furthermore, APPL1 decreases the activity of the GTPase Rac and its effector PAK, which in turn regulate cell migration. Thus, we demonstrate a novel role for the interaction between APPL1 and Rab5 in governing crosstalk between signaling and trafficking pathways on endosomes to affect cancer cell migration.This article has an associated First Person interview with the first author of the paper.

Computational drugs repositioning identifies inhibitors of oncogenic PI3K/AKT/P70S6K-dependent pathways among FDA-approved compounds

The discovery of inhibitors for oncogenic signalling pathways remains a key focus in modern oncology, based on personalized and targeted therapeutics. Computational drug repurposing via the analysis of FDA-approved drug network is becoming a very effective approach to identify therapeutic opportunities in cancer and other human diseases. Given that gene expression signatures can be associated with specific oncogenic mutations, we tested whether a "reverse" oncogene-specific signature might assist in the computational repositioning of inhibitors of oncogenic pathways. As a proof of principle, we focused on oncogenic PI3K-dependent signalling, a molecular pathway frequently driving cancer progression as well as raising resistance to anticancer-targeted therapies. We show that implementation of "reverse" oncogenic PI3K-dependent transcriptional signatures combined with interrogation of drug networks identified inhibitors of PI3K-dependent signalling among FDA-approved compounds. This led to repositioning of Niclosamide (Niclo) and Pyrvinium Pamoate (PP), two anthelmintic drugs, as inhibitors of oncogenic PI3K-dependent signalling. Niclo inhibited phosphorylation of P70S6K, while PP inhibited phosphorylation of AKT and P70S6K, which are downstream targets of PI3K. Anthelmintics inhibited oncogenic PI3K-dependent gene expression and showed a cytostatic effect in vitro and in mouse mammary gland. Lastly, PP inhibited the growth of breast cancer cells harbouring PI3K mutations. Our data indicate that drug repositioning by network analysis of oncogene-specific transcriptional signatures is an efficient strategy for identifying oncogenic pathway inhibitors among FDA-approved compounds. We propose that PP and Niclo should be further investigated as potential therapeutics for the treatment of tumors or diseases carrying the constitutive activation of the PI3K/P70S6K signalling axis.

Genome-Wide Analyses Identify Filamin-A As a Novel Downstream Target for Insulin and IGF1 Action

Insulin analogs were developed to improve diabetes therapy. However, certain modifications introduced into the insulin molecule were shown to enhance their affinity to the insulin-like growth factor-1 receptor (IGF1R). Most tumors, including endometrial cancers, express high levels of IGF1R. The present study was aimed at identifying the entire set of genes that are differentially activated by insulin glargine or detemir, in comparison to insulin and IGF1, in Type 1 and Type 2 endometrial cancer cell lines (ECC-1 and USPC-1, respectively). Global gene expression analyses demonstrated a ligand-dependent upregulated expression of filamin-A (FLNA), a gene that encodes an actin filament cross-linking protein, in both endometrial cancer cell types. Silencing experiments linked to migration assays confirmed the role of FLNA in cell growth and motility. Our data suggest that the activation of distinct sets of genes by glargine may lead to stimulation of specific pathways or, alternatively, may provide additive effects, different from those classically induced by insulin. Given that metastases are probably the main factor contributing to tumor invasiveness, the identification of FLNA as a downstream target for insulin-like hormones may be of translational relevance in oncology. Clinical studies in endometrial cancer may add further relevant information regarding the possible differential actions of insulin analogs with respect to native insulin.

Inhibition of CX3CR1 reduces cell motility and viability in pancreatic adenocarcinoma epithelial cells

Increased expression of the chemokine CX₃CL1 and its sole receptor, CX₃CR1 have been correlated with poor pancreatic cancer patient survival and time to recurrence, as well as with pancreatic perineural invasion. We have previously shown that metastasis of prostate and breast cancer is in part driven by CX₃CL1, and have developed small molecule inhibitors against the CX₃CR1 receptor that diminish metastatic burden. Here we ask if inhibition of this chemokine receptor affects the phenotype of PDAC tumor cells. Our findings demonstrate that motility, invasion, and contact-independent growth of PDAC cells all increase following CX₃CL1 exposure, and that antagonism of CX₃CR1 by the inhibitor JMS-17-2 reduces each of these phenotypes and correlates with a downregulation of AKT phosphorylation. These data suggest that PDAC tumor cell migration and growth, elements critical in metastatic progression, may susceptible to pharmacologic intervention.

Impact of Superparamagnetic Iron Oxide Nanoparticles on Vocal Fold Fibroblasts: Cell Behavior and Cellular Iron Kinetics

PURPOSE

The voice is the most important instrument of communication. Tissue defects in the vocal fold (VF) area lead to serious reduction in quality of life, but thus far, no satisfactory VF implant exists. Therefore, we aim to establish a functional VF implant in a rabbit model by magnetic tissue engineering (MTE) using superparamagnetic iron oxide nanoparticles (SPION). Hence, iron quantification over time as well as cell behavior studies upon SPION treatment are of great importance.

METHODS

Rabbit VF fibroblasts (VFF) were treated with different concentrations of SPIONs (20, 40, and 80 μg/cm²), and iron content was examined for up to 40 days using microwave plasma-atom emission spectroscopy. The effects of SPION treatment on VFF (adhesion, spreading, and migration), which are important for the formation of 3D structures, were tested.

RESULTS

Cellular SPION quantification revealed that there was no residual iron remaining in VFFs after 40 days. SPIONs had a dose-dependent effect on cell adhesion, with good tolerability observed up to 20 μg/cm². Migration and spreading were not significantly influenced by SPION treatment up to 80 μg/cm².

DISCUSSION AND CONCLUSION

To develop 3D structures, cell behavior should not be affected by SPION uptake. After 40 days, cells were free of iron as a result of metabolism or rarefication during cell division. Cell functions including adhesion, spreading, and migration were proven to be intact in a dose-dependent manner after SPION treatment, suggesting a safe usage of MTE for voice rehabilitation. Our results thus constitute a solid basis for a successful transfer of this technique into 3D constructs, in order to provide an individual and personalized human VF implant in the future.

Ripening-induced chemical modifications of papaya pectin inhibit cancer cell proliferation

Papaya (Carica papaya L.) is a fleshy fruit with a rapid pulp softening during ripening. Ripening events are accompanied by gradual depolymerization of pectic polysaccharides, including homogalacturonans, rhamnogalacturonans, arabinogalactans, and their modified forms. During intermediate phases of papaya ripening, partial depolymerization of pectin to small size with decreased branching had enhanced pectin anti-cancer properties. These properties were lost with continued decomposition at later phases of ripening. Pectin extracted from intermediate phases of papaya ripening markedly decreased cell viability, induced necroptosis, and delayed culture wound closing in three types of immortalized cancer cell lines. The possible explanation for these observations is that papaya pectins extracted from the third day after harvesting have disrupted interaction between cancer cells and the extracellular matrix proteins, enhancing cell detachment and promoting apoptosis/necroptosis. The anticancer activity of papaya pectin is dependent on the presence and the branch of arabinogalactan type II (AGII) structure. These are first reports of AGII in papaya pulp and the first reports of an in vitro biological activity of papaya pectins that were modified by natural action of ripening-induced pectinolytic enzymes. Identification of the specific pectin branching structures presents a biological route to enhancing anti-cancer properties in papaya and other climacteric fruits.

Butyrate suppresses motility of colorectal cancer cells via deactivating Akt/ERK signaling in histone deacetylase dependent manner

Butyrate is a typical short chain fatty acid produced by gut microbiota of which the dysmetabolism has been consistently associated with colorectal diseases. However, whether butyrate affects metastatic colorectal cancer is not clear. In this study we investigated in vitro the effect of butyrate on motility, a significant metastatic factor of colorectal cancer cells and explored the potential mechanism. By using wound healing and transwell-based invasion models, we demonstrated that pretreatment of butyrate significantly inhibited motility of HCT116, HT29, LOVO and HCT8 cells, this activity was further attributed to deactivation of Akt1 and ERK1/2. Suberanilohydroxamic acid (SAHA), another HDAC inhibitor, mimicked the inhibitory effect of butyrate on cell motility and deactivation of Akt/ERK. Furthermore, by silencing of HDAC3 with siRNA, we confirmed dependence of butyrate's effect on HDAC3, the similar reduced cell motility observed under HDAC3 silencing also indicates the significance of HDAC itself in cell motility. In conclusion, we confirmed the HDAC3-relied activity of butyrate on inhibiting motility of colorectal cancer cells via deactivating Akt/ERK signaling. Our data indicate that modulating butyrate metabolism is an effective therapeutic strategy of metastatic colorectal cancer; and HDAC3 might be a novel target for management of colorectal cancer metastasis.

Spermine oxidase promotes bile canalicular lumen formation through acrolein production

Spermine oxidase (SMOX) catalyzes oxidation of spermine to generate spermidine, hydrogen peroxide (H2O2) and 3-aminopropanal, which is spontaneously converted to acrolein. SMOX is induced by a variety of stimuli including bacterial infection, polyamine analogues and acetaldehyde exposure. However, the physiological functions of SMOX are not yet fully understood. We investigated the physiological role of SMOX in liver cells using human hepatocellular carcinoma cell line HepG2. SMOX localized to the bile canalicular lumen, as determined by F-actin staining. Knockdown of SMOX reduced the formation of bile canalicular lumen. We also found that phospho-Akt (phosphorylated protein kinase B) was localized to canalicular lumen. Treatment with Akt inhibitor significantly reduced the formation of bile canalicular lumen. Acrolein scavenger also inhibited the formation of bile canalicular lumen. PTEN, phosphatase and tensin homolog and an inhibitor of Akt, was alkylated in a SMOX-dependent manner. Our results suggest that SMOX plays a central role in the formation of bile canalicular lumen in liver cells by activating Akt pathway through acrolein production.

Integrated microRNA-mRNA analyses of distinct expression profiles in follicular thyroid tumors

MicroRNAs (miRNAs/miRs) are small non-coding RNAs identified in plants, animals and certain viruses; they function in RNA silencing and post-transcriptional regulation of gene expression. miRNAs also serve an important role in the pathogenesis, diagnosis and treatment of tumors. However, few studies have investigated the role of miRNAs in thyroid tumors. In the present study, the expression of miRNA and mRNA was compared between follicular thyroid carcinoma (FTC) and follicular thyroid adenoma (FA) samples, and then miRNA-mRNA regulatory network analysis was performed. Microarray datasets (GSE29315 and GSE62054) were downloaded from the Gene Expression Omnibus, and profiling data were processed with R software. Differentially expressed miRNAs (DEMs) and differentially expressed genes (DEGs) were determined, and Gene Ontology enrichment analysis was subsequently performed for DEGs using the Database for Annotation, Visualization and Integrated Discovery. The target genes of the DEMs were identified with miRWalk, miRecords and TarMir databases. Network analysis of the DEMs and DEMs-targeted DEGs was performed using Cytoscape software. In GSE62054, 23 downregulated and 9 upregulated miRNAs were identified. In GSE29315, 42 downregulated and 44 upregulated mRNAs were identified. A total of 36 miRNA-gene pairs were also identified. Network analysis indicated a co-regulatory association between miR-296-5p, miR-10a, miR-139-5p, miR-452, miR-493, miR-7, miR-137, miR-144, miR-145 and corresponding targeted mRNAs, including TNF receptor superfamily member 11b, benzodiazepine receptor (peripheral) -associated protein 1, and transforming growth factor β receptor 2. These results suggest that miRNA-mRNAs networks serve an important role in the pathogenesis, diagnosis and treatment of FTC and FA.

Analysis of miRNA profiles identified miR-196a as a crucial mediator of aberrant PI3K/AKT signaling in lung cancer cells

Hyperactivation of the PI3K/AKT pathway is observed in most human cancer including lung carcinomas. Here we have investigated the role of miRNAs as downstream targets of activated PI3K/AKT signaling in Non Small Cell Lung Cancer (NSCLC). To this aim, miRNA profiling was performed in human lung epithelial cells (BEAS-2B) expressing active AKT1 (BEAS-AKT1-E17K), active PI3KCA (BEAS-PIK3CA-E545K) or with silenced PTEN (BEAS-shPTEN).

Twenty-four differentially expressed miRNAs common to BEAS-AKT1-E17K, BEAS-PIK3CA-E545K and BEAS-shPTEN cells were identified through this analysis, with miR-196a being the most consistently up-regulated miRNA. Interestingly, miR-196a was significantly overexpressed also in human NSCLC-derived cell lines (n=11) and primary lung cancer samples (n=28).

By manipulating the expression of miR-196a in BEAS-2B and NCI-H460 cells, we obtained compelling evidence that this miRNA acts downstream the PI3K/AKT pathway, mediating some of the proliferative, pro-migratory and tumorigenic activity that this pathway exerts in lung epithelial cells, possibly through the regulation of FoxO1, CDKN1B (hereafter p27) and HOXA9.

The PI3Kδ Inhibitor Idelalisib Inhibits Homing in an in Vitro and in Vivo Model of B ALL

The quest continues for targeted therapies to reduce the morbidity of chemotherapy and to improve the response of resistant leukemia. Adhesion of acute lymphoblastic leukemia (ALL) cells to bone marrow stromal cells triggers intracellular signals that promote cell-adhesion-mediated drug resistance (CAM-DR). Idelalisib, an U.S. Food and Drug Administration (FDA)-approved PI3Kδ-specific inhibitor has been shown to be effective in CLL in down-regulating p-Akt and prolonging survival in combination with Rituximab; herein we explore the possibility of its use in B ALL and probe the mechanism of action. Primary B ALL in contact with OP9 stromal cells showed increased p-Akt^ser473. Idelalisib decreased p-Akt in patient samples of ALL with diverse genetic lesions. Addition of idelalisib to vincristine inhibited proliferation when compared to vincristine monotherapy in a subset of samples tested. Idelalisib inhibited ALL migration to SDF-1α in vitro and blocked homing of ALL cells to the bone marrow in vivo. This report tests PI3Kδ inhibitors in a more diverse group of ALL than has been previously reported and is the first published report of idelalisib inhibiting homing of ALL cells to bone marrow. Our data support further pre-clinical evaluation of idelalisib for the therapy of B ALL.

Inhibition of AKT1 signaling promotes invasion and metastasis of non-small cell lung cancer cells with K-RAS or EGFR mutations

Accumulating evidence supports a role of the PI3K-AKT pathway in the regulation of cell motility, invasion and metastasis. AKT activation is known to promote metastasis, however under certain circumstances, it also shows an inhibitory activity on metastatic processes, and the cause of such conflicting results is largely unclear. Here we found that AKT1 is an important regulator of metastasis and down-regulation of its activity is associated with increased metastatic potential of A549 cells. Inhibition of AKT1 enhanced migration and invasion in KRAS- or EGFR-mutant non-small cell lung cancer (NSCLC) cells. The allosteric AKT inhibitor MK-2206 promoted metastasis of KRAS-mutated A549 cells in vivo. We next identified that the phosphorylation of Myristoylated alanine-rich C-kinase substrate (MARCKS) and LAMC2 protein level were increased with AKT1 inhibition, and MARCKS or LAMC2 knockdown abrogated migration and invasion induced by AKT1 inhibition. This study unravels an anti-metastatic role of AKT1 in the NSCLC cells with KRAS or EGFR mutations, and establishes an AKT1-MARCKS-LAMC2 feedback loop in this regulation.

CBP501 inhibits EGF-dependent cell migration, invasion and epithelial-to-mesenchymal transition of non-small cell lung cancer cells by blocking KRas to calmodulin binding

The anti-cancer agent CBP501 binds to calmodulin (CaM). Recent studies showed that migration and metastasis are inhibited by several CaM antagonists. However, there is no available evidence that CBP501 has similar effects. Here we found that CBP501 inhibits migration of non-small cell lung cancer (NSCLC) cells in vitro, even in the presence of migration inducing factors such as WNT, IL-6, and several growth factors. CBP501 also inhibited epidermal growth factor (EGF) enhanced invasion and the epithelial-to-mesenchymal transition (EMT), and this inhibition was accompanied by (i) suppression of Akt and ERK1/2 phosphorylation, and (ii) suppression of expression of transcription factor Zeb1 and the mesenchymal marker Vimentin. A pull down analysis performed using sepharose-immobilized CaM showed that CBP501 blocks the interaction between CaM and KRas. Furthermore, EGF induced Akt activation and cell migration was effectively suppressed by KRas down-regulation in NSCLC cells. Stable knockdown of KRas also made cells insensitive to CBP501's inhibition of growth factor-induced migration. Taken together, these results indicate that CBP501 inhibits binding of CaM with KRas and thereby suppresses the PI3K/AKT pathway, migration, invasion and EMT. These findings have identified a previously unrecognized effect of CBP501 on downstream KRas signaling mechanisms involving EMT and invasion, and provide support for the further clinical development of this agent.

Enantiomerically pure β-dipeptide derivative induces anticancer activity against human hormone-refractory prostate cancer through both PI3K/Akt-dependent and -independent pathways

The use of peptides that target cancer cells and induce anticancer activities through various mechanisms is developing as a potential anticancer strategy. KUD983, an enantiomerically pure β-dipeptide derivative, displays potent activity against hormone-refractory prostate cancer (HRPC) PC-3 and DU145 cells with submicromolar IC₅₀. KUD983 induced G1 arrest of the cell cycle and subsequent apoptosis associated with down-regulation of several related proteins including cyclin D1, cyclin E and Cdk4, and the de-phosphorylation of RB. The levels of nuclear and total c-Myc protein, which could increase the expression of both cyclin D1 and cyclin E, were profoundly inhibited by KUD983. Furthermore, it inhibited PI3K/Akt and mTOR/p70S6K/4E-BP1 pathways, the key signaling in multiple cellular functions. The transient transfection of constitutively active myristylated Akt (myr-Akt) cDNA significantly rescued KUD983-induced caspase activation but did not blunt the inhibition of mTOR/p70S6K/4E-BP1 signaling cascade suggesting the presence of both Akt-dependent and -independent pathways. Moreover, KUD983-induced effect was enhanced with the down-regulation of anti-apoptotic Bcl-2 members (e.g., Bcl-2, and Mcl-1) and IAP family members (e.g., survivin). Notably, KUD983 induced autophagic cell death using confocal microscopic examination, tracking the level of conversion of LC3-I to LC3-II and flow cytometric detection of acidic vesicular organelles-positive cells. In conclusion, the data suggest that KUD983 is an anticancer β-dipeptide against HRPCs through the inhibition of cell proliferation and induction of apoptotic and autophagic cell death. The suppression of signaling pathways regulated by c-Myc, PI3K/Akt and mTOR/p70S6K/4E-BP1 and the collaboration with down-regulation of Mcl-1 and survivin may explain KUD983-induced anti-HRPC mechanism.

PKB/Akt-dependent regulation of inflammation in cancer

Chronic inflammation is a major cause of human cancer. Clinical cancer therapies against inflammatory risk factors are strategically determined. To rationally guide a novel drug development, an improved mechanistic understanding on the pathological connection between inflammation and carcinogenesis is essential. PI3K-PKB signaling axis has been extensively studied and shown to be one of the key oncogenic drivers in most types of cancer. Pharmacological inhibition of the components along this signaling axis is of great interest for developing novel therapies. Interestingly, emerging studies have shown a close association between PKB activation and inflammatory activity in the vicinity of the tumor, and either blockade of PKB or attenuation of para-tumoral inflammation reveals a mutual-interactive pattern through pathway crosstalk. In this review, we intend to discuss recent advances of PKB-regulated chronic inflammation and its potential impacts on tumor development.

Oncogenic β-catenin and PIK3CA instruct network states and cancer phenotypes in intestinal organoids

Colorectal cancer is driven by cooperating oncogenic mutations. In this study, we use organotypic cultures derived from transgenic mice inducibly expressing oncogenic β-catenin and/or PIK3CA^H1047R to follow sequential changes in cancer-related signaling networks, intestinal cell metabolism, and physiology in a three-dimensional environment mimicking tissue architecture. Activation of β-catenin alone results in the formation of highly clonogenic cells that are nonmotile and prone to undergo apoptosis. In contrast, coexpression of stabilized β-catenin and PIK3CA^H1047R gives rise to intestinal cells that are apoptosis-resistant, proliferative, stem cell-like, and motile. Systematic inhibitor treatments of organoids followed by quantitative phenotyping and phosphoprotein analyses uncover key changes in the signaling network topology of intestinal cells after induction of stabilized β-catenin and PIK3CA^H1047R We find that survival and motility of organoid cells are associated with 4EBP1 and AKT phosphorylation, respectively. Our work defines phenotypes, signaling network states, and vulnerabilities of transgenic intestinal organoids as a novel approach to understanding oncogene activities and guiding the development of targeted therapies.

p-Akt as a potential poor prognostic factor for gastric cancer: a systematic review and meta-analysis

To understand the relationship between p-Akt expression and the prognosis of patients with gastric cancer, we searched six databases, Pubmed, EMBASE, Cochrane Library, CNKI, Wanfang and CBM for relevant articles in order to conduct this metaanalysis. The pooled hazard ratios and corresponding 95%CI of overall survival were calculated to evaluate the prognostic value of p-Akt expression in patients with gastric cancer. With 2261 patients combined from 13 available studies, the pooled HR showed a poor prognosis in patients with gastric cancer in the univariate analysis (HR=1.88, 95%CI:1.45-2.43, P<0.00001), and the group "univariate analysis+estimate" (HR=1.41, 95%CI: 1.01-1.97, P=0.04), but not in multivariate analysis (HR=0.66, 95%CI: 0.29-1.52, P=0.33) and estimate (HR=1.13, 95%CI: 0.65-1.95, P=0.67). In conclusion, our results indicated that p-Akt was likely to be an indicator of poor prognosis in patients with gastric cancer.