Prognostic signature of colorectal cancer based on uric acid-related genes

Colorectal cancer (CRC) is one of the deadliest cancers worldwide. Numerous studies have reported a correlation between uric acid (UA) level and CRC risk. Here, we investigated the role and prognostic value of UA-related genes in CRC progression. CRC-associated gene expression and clinical data were retrieved from The Cancer Genome Atlas (TCGA), and UA-related genes were identified by overlapping the TCGA and GeneCards databases. The Gene Ontology annotation, Kyoto Encyclopedia of Genes and Genomes pathway, and Molecular Signatures Database dataset were subjected to gene set enrichment analysis. A prognostic model was constructed using the univariate and multivariate COX regression and least absolute shrinkage and selection operator (LASSO) analyses and validated using the Gene Expression Omnibus cohort. Competing endogenous RNA network, CellMiner, and Human Protein Atlas were used to detect the signature of 13 UA-related genes in the prediction model. The expression of five potential UA-related genes in CRC cell lines was confirmed via qPCR. CIBERSORT was used to evaluate immune cell infiltration in the TCGA-CRC dataset. Thirteen highly prognostic UA-related genes were used to construct a prognostic model of CRC with risk score accuracy and predictive efficacy. Abundance of activated M0 macrophages, monocytes, CD8+ T cells, and natural killer cells positively correlated with the risk score. Five promising UA-related genes showed higher expression levels in CRC than in colonic cell lines. Thus, our model posits a direct relationship between UA-related genes and CRC risk, offering novel insights into diagnosis, prognosis, and treatment.

The LIM domain protein nTRIP6 modulates the dynamics of myogenic differentiation

The process of myogenesis which operates during skeletal muscle regeneration involves the activation of muscle stem cells, the so-called satellite cells. These then give rise to proliferating progenitors, the myoblasts which subsequently exit the cell cycle and differentiate into committed precursors, the myocytes. Ultimately, the fusion of myocytes leads to myofiber formation. Here we reveal a role for the transcriptional co-regulator nTRIP6, the nuclear isoform of the LIM-domain protein TRIP6, in the temporal control of myogenesis. In an in vitro model of myogenesis, the expression of nTRIP6 is transiently up-regulated at the transition between proliferation and differentiation, whereas that of the cytosolic isoform TRIP6 is not altered. Selectively blocking nTRIP6 function results in accelerated early differentiation followed by deregulated late differentiation and fusion. Thus, the transient increase in nTRIP6 expression appears to prevent premature differentiation. Accordingly, knocking out the Trip6 gene in satellite cells leads to deregulated skeletal muscle regeneration dynamics in the mouse. Thus, dynamic changes in nTRIP6 expression contributes to the temporal control of myogenesis.

TRIP6 accelerates the proliferation and invasion of cervical cancer by upregulating oncogenic YAP signaling

Accumulating evidence has suggested that thyroid hormone receptor interacting protein 6 (TRIP6) is a novel tumor-related regulator that is aberrantly expressed in multiple tumors and contributes to tumor progression and metastasis. Yet, little is known about the role of TRIP6 in cervical cancer. In the current study, we aimed to explore the expression, biological function, and regulatory mechanism of TRIP6 in cervical cancer. Here we showed that TRIP6 expression was markedly upregulated in cervical cancer tissues and cell lines. The knockdown of TRIP6 suppressed the proliferation, colony formation, and invasive potential of cervical cancer cells, whereas TRIP6 overexpression exhibited the opposite effect. Moreover, TRIP6 contributes to the activation of Yes-associated protein (YAP) by downregulating the level of YAP phosphorylation. Notably, TRIP6-mediated tumor promotion effect was partially reversed by YAP inhibition. In addition, TRIP6 knockdown retarded the in vivo tumor growth of cervical cancer of mouse xenograft models associated with downregulation of YAP activation in tumor tissues. Taken together, these results reveal a potential tumor promotion role of TRIP6 that facilitates the proliferation and invasion of cervical cancer through activation of YAP. Our study underlines the importance of the TRIP6/YAP axis in cervical cancer and suggests TRIP6 as a potential anticancer candidate for cervical cancer.

Insulin-Like Growth Factor 2 mRNA-Binding Protein 3 Modulates Aggressiveness of Ewing Sarcoma by Regulating the CD164-CXCR4 Axis

Ewing sarcoma (EWS) is the second most common bone and soft tissue-associated malignancy in children and young adults. It is driven by the fusion oncogene EWS/FLI1 and characterized by rapid growth and early metastasis. We have previously discovered that the mRNA binding protein IGF2BP3 constitutes an important biomarker for EWS as high expression of IGF2BP3 in primary tumors predicts poor prognosis of EWS patients. We additionally demonstrated that IGF2BP3 enhances anchorage-independent growth and migration of EWS cells suggesting that IGF2BP3 might work as molecular driver and predictor of EWS progression. The aim of this study was to further define the role of IGF2BP3 in EWS progression. We demonstrated that high IGF2BP3 mRNA expression levels correlated with EWS metastasis and disease progression in well-characterized EWS tumor specimens. EWS tumors with high IGF2BP3 levels were characterized by a specific gene signature enriched in chemokine-mediated signaling pathways. We also discovered that IGF2BP3 regulated the expression of CXCR4 through CD164. Significantly, CD164 and CXCR4 colocalized at the plasma membrane of EWS cells upon CXCL12 stimulation. We further demonstrated that IGF2BP3, CD164, and CXCR4 expression levels correlated in clinical samples and the IGF2BP3/CD164/CXCR4 signaling pathway promoted motility of EWS cells in response to CXCL12 and under hypoxia conditions. The data presented identified CD164 and CXCR4 as novel IGF2BP3 downstream functional effectors indicating that the IGF2BP3/CD164/CXCR4 oncogenic axis may work as critical modulator of EWS aggressiveness. In addition, IGF2BP3, CD164, and CXCR4 expression levels may constitute a novel biomarker panel predictive of EWS progression.

The YAP/TAZ Pathway in Osteogenesis and Bone Sarcoma Pathogenesis

YAP and TAZ are intracellular messengers communicating multiple interacting extracellular biophysical and biochemical cues to the transcription apparatus in the nucleus and back to the cell/tissue microenvironment interface through the regulation of cytoskeletal and extracellular matrix components. Their activity is negatively and positively controlled by multiple phosphorylation events. Phenotypically, they serve an important role in cellular plasticity and lineage determination during development. As they regulate self-renewal, proliferation, migration, invasion and differentiation of stem cells, perturbed expression of YAP/TAZ signaling components play important roles in tumorigenesis and metastasis. Despite their high structural similarity, YAP and TAZ are functionally not identical and may play distinct cell type and differentiation stage-specific roles mediated by a diversity of downstream effectors and upstream regulatory molecules. However, YAP and TAZ are frequently looked at as functionally redundant and are not sufficiently discriminated in the scientific literature. As the extracellular matrix composition and mechanosignaling are of particular relevance in bone formation during embryogenesis, post-natal bone elongation and bone regeneration, YAP/TAZ are believed to have critical functions in these processes. Depending on the differentiation stage of mesenchymal stem cells during endochondral bone development, YAP and TAZ serve distinct roles, which are also reflected in bone tumors arising from the mesenchymal lineage at different developmental stages. Efforts to clinically translate the wealth of available knowledge of the pathway for cancer diagnostic and therapeutic purposes focus mainly on YAP and TAZ expression and their role as transcriptional co-activators of TEAD transcription factors but rarely consider the expression and activity of pathway modulatory components and other transcriptional partners of YAP and TAZ. As there is a growing body of evidence for YAP and TAZ as potential therapeutic targets in several cancers, we here interrogate the applicability of this concept to bone tumors. To this end, this review aims to summarize our current knowledge of YAP and TAZ in cell plasticity, normal bone development and bone cancer.

TRIP6 accelerates the proliferation and migration of fetal airway smooth muscle cells by enhancing YAP activation

The thyroid receptor interactor protein 6 (TRIP6) has emerged as a key regulator for the proliferation and migration of various cells. However, whether TRIP6 is involved in regulating the proliferation and migration of airway smooth muscle (ASM) cells in the progression of pediatric asthma remains undetermined. The present study investigated the function of TRIP6 in regulating the proliferation and migration of fetal ASM cells induced by tumor necrosis factor (TNF)-α in vitro. The results revealed that TRIP6 expression was significantly upregulated in TNF-α-stimulated ASM cells. Loss-of-function experiments demonstrated that the knockdown of TRIP6 markedly suppressed TNF-α-proliferation and migration of ASM cells. By contrast, overexpression of TRIP6 had the opposite effect. In-depth research uncovered that TNF-α stimulation promoted the activation of yes-associated protein (YAP), which could be significantly reversed by TRIP6 silencing. Moreover, inactivation of YAP significantly reversed the promotion effect of TRIP6 overexpression on TNF-α-induced ASM cell proliferation and migration. Overall, these results reveal that upregulation of TRIP6 contributes to the proliferation and migration of fetal ASM cells by enhancing YAP activation, highlighting the importance of the TRIP6/YAP axis in the airway remodeling of pediatric asthma.

TRIP6 regulates the proliferation, migration, invasion and apoptosis of osteosarcoma cells by activating the NF-κB signaling pathway

Thyroid hormone receptor-interacting protein 6 (TRIP6), a member of the zyxin family of Lin-Isl-Mec (LIM) proteins, is an adaptor protein primarily expressed in epithelial cells. TRIP6 can regulate a variety of cellular responses, such as actin cytoskeletal reorganization and cell adhesion. However, to the best of our knowledge, the role of TRIP6 in osteosarcoma (Os) has not been previously reported. Therefore, the present study investigated the role of TRIP6 in the occurrence and development of Os, and the potential of utilizing TRIP6 as a therapeutic target in Os. The present results suggested that the expression levels of TRIP6 were significantly increased in Os cells and clinical tissue specimens compared with normal osteoblasts and adjacent non-tumor tissue. Moreover, the present results suggested that overexpressing TRIP6 significantly increased proliferation, migration and invasion, while inhibiting apoptosis in Os cells. However, silencing TRIP6 decreased proliferation, migration and invasion, while activating apoptosis in Os cells. The present results suggested that overexpression of TRIP6 increased NF-κB activation by decreasing the protein expression levels of inhibitor of κBα, and increasing total and phosphorylated P65 levels. The present results indicated that TRIP6 silencing decreased NF-κB activation. Collectively, the present results suggested that TRIP6 may play a role in promoting Os cell proliferation, migration and invasion, while inhibiting cell apoptosis. Furthermore, TRIP6 may be utilized as a novel prognostic biomarker and therapeutic target in Os.

TRIP6 promotes tumorigenic capability through regulating FOXC1 in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is an aggressive malignant tumor with poor prognosis that is characterized by high rates of postoperative recurrence and mortality. Understanding the molecular mechanism of this malignancy is of great significance for the development of new and effective strategies for the treatment of hepatocellular carcinoma. Thyroid hormone receptor-interacting protein 6 (TRIP6), also known as zyxin-related protein-1 or ZRP-1, is an adaptor protein that belongs to the zyxin family of LIM proteins. Recent studies showed that TRIP6 is involved in carcinogenesis. But the functional role of TRIP6 in HCC has not been reported to date.

METHODS

TRIP6 expression level in HCC cell lines and normal cell line was measured by qPCR. The roles of TRIP6 on HCC cell proliferation, colony formation, and invasion were examined by MTT assay, colony formation assay, and transwell invasion assay, respectively. The effect of TRIP6 on the overall survival of HCC patients was further analyzed. ChIP assay and western blot were performed to validate whether FOXC1 was involved in the regulation of TRIP6 expression.

RESULTS

Western blot and immunohistochemical analyses showed that TRIP6 expression was up-regulated in HCC tissues compared with adjacent non-tumor tissues. Kaplan-Meier survival analysis indicated that upregulation of TRIP6 was dramatically associated with poor overall survival. TRIP6 knockdown significantly inhibited cell migration, invasion, and proliferation, and its effect on cell proliferation was mediated by the modulation of cell cycle progression. FOXC1 also played a vital role in TRIP6 regulation. TRIP6 mediated the FOXC1-regulated proliferation, invasion, and migration in vitro and tumor growth in vivo.

CONCLUSIONS

These results suggest that TRIP6 may contribute to the invasiveness and metastasis of HCC cells, and provide new insight into the crucial role of TRIP6 in tumorigenesis and cancer progression.

Targeting Thyroid Receptor Interacting Protein 6 by MicroRNA-589-5p Inhibits Cell Proliferation, Migration, and Invasion in Endometrial Carcinoma

Background: MicroRNA-589-5p (miR-589-5p) has been recently reported to be aberrantly regulated in hepatocellular carcinoma, but its functional role and molecular mechanisms still remains unknown in the endometrial carcinoma (EC) as one of the most common female malignancies. Methods: EC tissues and adjacent tissues were collected to determine the expression of miR-589-5p and thyroid receptor interacting protein 6 (TRIP6) using quantitative real time-PCR. Subsequently, two EC cell lines HEC-1B and AN3CA were transfected with miR-589-5p to achieve miR-589-5p overexpression. Using Cell Counting Kit-8 (CCK-8), a wound healing assay and the Transwell assay, we analyzed cell proliferation, migration and invasion. Dual-luciferase reporter assay confirmed that thyroid receptor interacting protein 6 (TRIP6) was a direct target of miR-589-5p. Results: We first observed that miR-589-5p was down-regulated in EC tissues compared with normal endometrial tissues. MiR-589-5p overexpression significantly suppressed EC cell proliferation, migration and invasion. Thyroid receptor interacting protein 6 (TRIP6) was a direct target of miR-589-5p. Besides, TRIP6 knockdown presented similar effects on cell proliferation, migration and invasion to miR-589-5p overexpression. Furthermore, TRIP6 knockdown efficiently enhanced the effects of miR-589-5p on the above cellular function. Moreover, miR-589-5p up-regulated E-cadherin expression, but down-regulated N-cadherin and Vimentin by targeting TRIP6. Conclusions: In summary, miR-589-5p might function as a tumor suppressor by targeting TRIP6, which will provide new insights into the molecular mechanism underlying the development of EC.

TRIP6 functions as a potential oncogene and facilitated proliferation and metastasis of gastric cancer

Background: Increasing evidence suggests that TRIP6 has been considered to be aberrantly regulated in several malignancies and involved in tumor growth and metastasis. However, the biological role and prognostic significance of TRIP6 in gastric cancer (GC) still remains unclear.

Materials and methods: TRIP6 expression was determined in matched GC tissues and adjacent normal tissues by western blot and real-time PCR. Then, immunohistochemistry was used to detect the expression of TRIP6 in GC patients. Statistical analysis was performed to evaluate the correlation between TRIP6 expression and clinicopathological characteristics and prognosis. Moreover, the effects of TRIP6 on GC cell proliferation and migration were also investigated by using MTT, colony formation and transwell assays.

Results: We observed that the expression of TRIP6 was significantly up-regulated in GC tissues and cell ines. Our data indicated that high TRIP6 expression exhibited a significant correlation with poor prognosis for GC patients. Multivariate analysis showed that TRIP6 expression was an independent prognostic factor of the overall survival of GC patients. Furthermore, ectopic expression of TRIP6 promotes cell proliferation and migration in BGC823 cells, whereas knockdown of TRIP6 suppresses cell proliferation and migration in MKN45 cells.

Conclusion: These findings demonstrate that TRIP6 exerts an important role in cancer development, which represents a potential prognostic indicator in GC.

Insight into the Etiology of Undifferentiated Soft Tissue Sarcomas from a Novel Mouse Model

Aberrant activation of the Hedgehog signaling pathway has been linked to the formation of numerous cancer types, including the myogenic soft tissue sarcoma, embryonal rhabdomyosarcoma (eRMS). Here, we report PCG2, a novel mouse model in which human GLI2A, a constitutive activator of Hedgehog signaling, induced undifferentiated sarcomas that were phenotypically divergent from eRMS. Rather, sarcomas arising in PCG2 mice featured some characteristics that were reminiscent of Ewing sarcoma. Even though it is widely understood that Ewing sarcoma formation is driven by EWS-ETS gene fusions, a genetically defined mouse model is not well-established. While EWS-ETS gene fusions were not present in PCG2 sarcomas, precluding their designation as Ewing sarcoma, we did find that GLI2A induced expression of known EWS-ETS gene targets essential to Ewing pathogenesis, most notably, Nkx2.2. Moreover, we found that naïve mesenchymal progenitors originate tumors in PCG2 mice. Altogether, our work provides a novel genetic mouse model, which directly connects oncogenic Hedgehog activity to the etiology of undifferentiated soft tissue sarcomas for the first time. IMPLICATIONS: The finding that activation of Gli2 transcription factor is sufficient to induce Ewing-like sarcomas provides a direct transformative role of the Hedgehog signaling pathway in undifferentiated soft tissue sarcoma.

LINC00675 is a prognostic factor and regulates cell proliferation, migration and invasion in glioma

LINC00675 has been suggested to be dysregulated in gastric cancer, colorectal cancer and pancreatic cancer. However, the expression status and biological function of LINC00675 in glioma were still unknown. Thus, we reported LINC00675 was overexpressed in glioma tissues and cell lines, and positively associated with advanced WHO grade, large tumor size and poor prognosis. Moreover, univariate and multivariate analyses suggested that high-expression of LINC00675 was an independent unfavorable prognostic predictor for glioma. In addition, levels of LINC00675 expression were positively correlated with TRIP6 mRNA and protein expressions. The in vitro experiment showed that silencing of LINC00675 inhibits glioma cell proliferation, migration and invasion through regulating TRIP6. In conclusion, LINC00675 acts as a tumor promoter in glioma progression.

Ewing sarcoma

Ewing sarcoma is the second most frequent bone tumour of childhood and adolescence that can also arise in soft tissue. Ewing sarcoma is a highly aggressive cancer, with a survival of 70-80% for patients with standard-risk and localized disease and ~30% for those with metastatic disease. Treatment comprises local surgery, radiotherapy and polychemotherapy, which are associated with acute and chronic adverse effects that may compromise quality of life in survivors. Histologically, Ewing sarcomas are composed of small round cells expressing high levels of CD99. Genetically, they are characterized by balanced chromosomal translocations in which a member of the FET gene family is fused with an ETS transcription factor, with the most common fusion being EWSR1-FLI1 (85% of cases). Ewing sarcoma breakpoint region 1 protein (EWSR1)-Friend leukaemia integration 1 transcription factor (FLI1) is a tumour-specific chimeric transcription factor (EWSR1-FLI1) with neomorphic effects that massively rewires the transcriptome. Additionally, EWSR1-FLI1 reprogrammes the epigenome by inducing de novo enhancers at GGAA microsatellites and by altering the state of gene regulatory elements, creating a unique epigenetic signature. Additional mutations at diagnosis are rare and mainly involve STAG2, TP53 and CDKN2A deletions. Emerging studies on the molecular mechanisms of Ewing sarcoma hold promise for improvements in early detection, disease monitoring, lower treatment-related toxicity, overall survival and quality of life.

Novel metastatic models of esophageal adenocarcinoma derived from FLO-1 cells highlight the importance of E-cadherin in cancer metastasis

There is currently a paucity of preclinical models available to study the metastatic process in esophageal cancer. Here we report FLO-1, and its isogenic derivative FLO-1LM, as two spontaneously metastatic cell line models of human esophageal adenocarcinoma. We show that FLO-1 has undergone epithelial-mesenchymal transition and metastasizes following subcutaneous injection in mice. FLO-1LM, derived from a FLO-1 liver metastasis, has markedly enhanced proliferative, clonogenic, anti-apoptotic, invasive, immune-tolerant and metastatic potential. Genome-wide RNAseq profiling revealed a significant enrichment of metastasis-related pathways in FLO-1LM cells. Moreover, CDH1, which encodes the adhesion molecule E-cadherin, was the most significantly downregulated gene in FLO-1LM compared to FLO-1. Consistent with this, repression of E-cadherin expression in FLO-1 cells resulted in increased metastatic activity. Importantly, reduced E-cadherin expression is commonly reported in esophageal adenocarcinoma and independently predicts poor patient survival. Collectively, these findings highlight the biological importance of E-cadherin activity in the pathogenesis of metastatic esophageal adenocarcinoma and validate the utility of FLO-1 parental and FLO-1LM cells as preclinical models of metastasis in this disease.

TRIP6 inhibits Hippo signaling in response to tension at adherens junctions

The transcriptional co-activator YAP controls cell proliferation, survival, and tissue regeneration in response to changes in the mechanical environment. It is not known how mechanical stimuli such as tension are sensed and how the signal is transduced to control YAP activity. Here, we show that the LIM domain protein TRIP6 acts as part of a mechanotransduction pathway at adherens junctions to promote YAP activity by inhibiting the LATS1/2 kinases. Previous studies showed that vinculin at adherens junctions becomes activated by mechanical tension. We show that vinculin inhibits Hippo signaling by recruiting TRIP6 to adherens junctions and stimulating its binding to and inhibition of LATS1/2 in response to tension. TRIP6 competes with MOB1 for binding to LATS1/2 thereby blocking MOB1 from recruiting the LATS1/2 activating kinases MST1/2. Together, these findings reveal a novel pathway that responds to tension at adherens junctions to control Hippo pathway signaling.

[Functional genomics of Ewing sarcoma]

Ewing sarcoma is a highly aggressive bone or soft-tissue tumor mostly occurring in children and adolescents. Conventional multi-modal therapies are associated with considerable acute and chronic toxicity. Thus, more effective and in particular less toxic therapeutic strategies are urgently required. Despite the fact that Ewing sarcoma is characterized by specific EWSR1-ETS gene fusions, the resulting fusion oncoproteins are not suitable for targeted therapy due to their low immunogenicity and the ubiquitous expression of their constituents. However, functional genomics revealed several EWSR1-ETS target genes, which are only minimally expressed in normal tissues, and which could serve as surrogate-targets for (immuno-)therapeutic approaches. Moreover, functional genomic analyses yielded first mechanistic explanations for the relatively high incidence of Ewing sarcoma in Europeans, and first studies are exploring the value of circulating free DNA and/or exosomal mRNA of EWSR1-ETS fusion oncogenes as minimal-residual-disease markers in Ewing sarcoma. This review summarizes key contributions to these aspects and gives a perspective on their medical relevance.

Emerging roles for LPP in metastatic cancer progression

LIM domain containing proteins are important regulators of diverse cellular processes, and play pivotal roles in regulating the actin cytoskeleton. Lipoma Preferred Partner (LPP) is a member of the zyxin family of LIM proteins that has long been characterized as a promoter of mesenchymal/fibroblast cell migration. More recently, LPP has emerged as a critical inducer of tumor cell migration, invasion and metastasis. LPP is thought to contribute to these malignant phenotypes by virtue of its ability to shuttle into the nucleus, localize to adhesions and, most recently, to promote invadopodia formation. In this review, we will examine the mechanisms through which LPP regulates the functions of adhesions and invadopodia, and discuss potential roles of LPP in mediating cellular responses to mechanical cues within these mechanosensory structures.

MicroRNA‑138‑5p regulates neural stem cell proliferation and differentiation in vitro by targeting TRIP6 expression

Research on neural stem cells (NSCs) has recently focused on microRNAs (miRNAs), a class of small non-coding RNAs that have crucial roles in regulating NSC proliferation and differentiation. In the present study, a quantitative-polymerase chain reaction assay revealed that the expression of miRNA (miR)-138-5p was significantly decreased during neural differentiation of NSCs in vitro. Overexpression of miR-138-5p reduced NSC proliferation and increased NSC differentiation. Furthermore, suppression of miR-138-5p via transfection with a miRNA inhibitor enhanced NSC proliferation and attenuated NSC differentiation. Additionally, expression of thyroid hormone receptor interacting protein 6 (TRIP6), a critical regulator of NSCs, was negatively correlated with the miR-138-5p level. A luciferase assay demonstrated that miR-138-5p regulate TRIP6 by directly binding the 3′-untranslated region of the mRNA. Additionally, upregulation of TRIP6 rescued the NSC proliferation deficiency induced by miR-138-5p and abolished miR-138-5p-promoted NSCs differentiation. By contrast, downregulation of TRIP6 produced the opposite effect on proliferation and differentiation of NSCs transfected with anti-miR-138-5p. Taken together, the data suggest that miR-138-5p regulates NSCs proliferation and differentiation, and may be useful in developing novel treatments for neurological disorders via manipulation of miR-138-5p in NSCs.

LASP1, a Newly Identified Melanocytic Protein with a Possible Role in Melanin Release, but Not in Melanoma Progression

The LIM and SH3 protein 1 (LASP1) is a focal adhesion protein. Its expression is increased in many malignant tumors. However, little is known about the physiological role of the protein. In the present study, we investigated the expression and function of LASP1 in normal skin, melanocytic nevi and malignant melanoma. In normal skin, a distinct LASP1 expression is visible only in the basal epidermal layer while in nevi LASP1 protein is detected in all melanocytes. Melanoma exhibit no increase in LASP1 mRNA compared to normal skin. In melanocytes, the protein is bound to dynamin and mainly localized at late melanosomes along the edges and at the tips of the cell. Knockdown of LASP1 results in increased melanin concentration in the cells. Collectively, we identified LASP1 as a hitherto unknown protein in melanocytes and as novel partner of dynamin in the physiological process of membrane constriction and melanosome vesicle release.

Tumour-derived exosomes: Tiny envelopes for big stories

The discovery of exosomes, which are small, 30-100 nm sized extracellular vesicles that are released by virtual all cells, has initiated a rapidly expanding and vibrant research field. Current investigations are mainly directed toward the role of exosomes in intercellular communication and their potential value as biomarkers for a broad set of diseases. By horizontal transfer of molecular information such as micro RNAs, messenger RNAs or proteins, as well as by receptor-cell interactions, exosomes are capable to mediate the reprogramming of surrounding cells. Herein, we review how especially cancer cells take advantage of this mechanism to influence their microenvironment in favour of immune escape, therapy resistance, tumour growth and metastasis. Moreover, we provide a comprehensive microarray analysis (n > 1970) to study the expression patterns of genes known to be intimately involved in exosome biogenesis across 26 different cancer entities and a normal tissue atlas. Consistent with the elevated production of exosomes observed in cancer patient plasma, we found a significant overexpression especially of RAB27A, CHMP4C and SYTL4 in the corresponding cancer entities as compared to matched normal tissues. Finally, we discuss the immune-modulatory and anti-tumorigenic functions of exosomes as well as innovative approaches to specifically target the exosomal circuits in experimental cancer therapy.

Recruitment and activation of SLK at the leading edge of migrating cells requires Src family kinase activity and the LIM-only protein 4

The Ste20-like kinase SLK plays a pivotal role in cell migration and focal adhesion turnover and is regulated by the LIM domain-binding proteins Ldb1 and Ldb2. These adapter proteins have been demonstrated to interact with LMO4 in the organization of transcriptional complexes. Therefore, we have assessed the ability of LMO4 to also interact and regulate SLK activity. Our data show that LMO4 can directly bind to SLK and activate its kinase activity in vitro and in vivo. LMO4 can be co-precipitated with SLK following the induction of cell migration by scratch wounding and Cre-mediated deletion of LMO4 in conditional LMO4(fl/fl) fibroblasts inhibits cell migration and SLK activation. Deletion of LMO4 impairs Ldb1 and SLK recruitment to the leading edge of migrating cells. Supporting this, Src/Yes/Fyn-deficient cells (SYF) expressing very low levels of LMO4 do not recruit SLK to the leading edge. Re-expression of wildtype Myc-LMO4 in SYF cells, but not a mutant version, restores SLK localization and kinase activity. Overall, our data suggest that activation of SLK by haptotactic signals requires its recruitment to the leading edge by LMO4 in a Src-dependent manner. Furthermore, this establishes a novel cytosolic role for the transcriptional co-activator LMO4.

Genome-wide DNA methylation identifies trophoblast invasion-related genes: Claudin-4 and Fucosyltransferase IV control mobility via altering matrix metalloproteinase activity

Previously we showed that extravillous cytotrophoblast (EVT) outgrowth and migration on a collagen gel explant model were affected by exposure to decidual natural killer cells (dNK). This study investigates the molecular causes behind this phenomenon. Genome wide DNA methylation of exposed and unexposed EVT was assessed using the Illumina Infinium HumanMethylation450 BeadChip array (450 K array). We identified 444 differentially methylated CpG loci in dNK-treated EVT compared with medium control (P < 0.05). The genes associated with these loci had critical biological roles in cellular development, cellular growth and proliferation, cell signaling, cellular assembly and organization by Ingenuity Pathway Analysis (IPA). Furthermore, 23 mobility-related genes were identified by IPA from dNK-treated EVT. Among these genes, CLDN4 (encoding claudin-4) and FUT4 (encoding fucosyltransferase IV) were chosen for follow-up studies because of their biological relevance from research on tumor cells. The results showed that the mRNA and protein expressions of both CLDN4 and FUT4 in dNK-treated EVT were significantly reduced compared with control (P < 0.01 for both CLDN4 and FUT4 mRNA expression; P < 0.001 for CLDN4 and P < 0.01 for FUT4 protein expression), and were inversely correlated with DNA methylation. Knocking down CLDN4 and FUT4 by small interfering RNA reduced trophoblast invasion, possibly through the altered matrix metalloproteinase (MMP)-2 and/or MMP-9 expression and activity. Taken together, dNK alter EVT mobility at least partially in association with an alteration of DNA methylation profile. Hypermethylation of CLDN4 and FUT4 reduces protein expression. CLDN4 and FUT4 are representative genes that participate in modulating trophoblast mobility.

Anti-oxidative stress response genes: bioinformatic analysis of their expression and relevance in multiple cancers

Cells mount a transcriptional anti-oxidative stress (AOS) response program to scavenge reactive oxygen species (ROS) that arise from chemical, physical, and metabolic challenges. This protective program has been shown to reduce carcinogenesis triggered by chemical and physical insults. However, it is also hijacked by established cancers to thrive and proliferate within the hostile tumor microenvironment and to gain resistance against chemo- and radiotherapies. Therefore, targeting the AOS response proteins that are exploited by cancer cells is an attractive therapeutic strategy. In order to identify the AOS genes that are suspected to support cancer progression and resistance, we analyzed the expression patterns of 285 genes annotated for being involved in oxidative stress in 994 tumors and 353 normal tissues. Thereby we identified a signature of 116 genes that are highly overexpressed in multiple carcinomas while being only minimally expressed in normal tissues. To establish which of these genes are more likely to functionally drive cancer resistance and progression, we further identified those whose overexpression correlates with negative patient outcome in breast and lung carcinoma. Gene-set enrichment, GO, network, and pathway analyses revealed that members of the thioredoxin and glutathione pathways are prominent components of this oncogenic signature and that activation of these pathways is common feature of many cancer entities. Interestingly, a large fraction of these AOS genes are downstream targets of the transcription factors NRF2, NF-kappaB and FOXM1, and relay on NADPH for their enzymatic activities highlighting promising drug targets. We discuss these findings and propose therapeutic strategies that may be applied to overcome cancer resistance.