NEDD9 and BCAR1 negatively regulate E-cadherin membrane localization, and promote E-cadherin degradation

Karyotype-phenotype correlation in partial trisomies of the short arm of chromosome 6: a family case report and review of the literature

The first child (proband) of nonconsanguineous Caucasian parents underwent genetic investigation because she was affected with congenital choanal atresia, heart defects and kidney hyposplasia with mild transient renal insufficiency. The direct DNA sequencing after PCR of the CHD7 gene, which is thought to be responsible for approximately 60-70% of the cases of CHARGE syndrome/association, found no mutations. The cytogenetic analysis (standard GTG banding karyotype) revealed the presence of extrachromosomal material on 10q. The chromosome analysis was completed with array CGH (30 kb resolution), MLPA and FISH, which allowed the identification of three 6p regions (6p.25.3p23 × 3): 2 of these regions are normally located on chromosome 6, and the third region is translocated to the long arm of chromosome 10. The same chromosomal rearrangement was subsequently found in the father, who was affected with congenital ptosis and progressive hearing loss, and in the proband's sister, the second child, who presented at birth with choanal atresia and congenital heart defects. The mutated karyotypes, which were directly inherited, are thought to be responsible for a variable phenotype, including craniofacial dysmorphisms, choanal atresia, congenital ptosis, sensorineural hearing loss, heart defects, developmental delay, and renal dysfunction. Nevertheless, to achieve a complete audiological assessment of the father, he underwent further investigation that revealed an increased level of the coagulation factor XIII (300% increased activity), fluctuating levels of fibrin D-dimer degradation products (from 296 to 1,587 ng/ml) and a homoplasmic mitochondrial DNA mutation: T961G in the MTRNR1 (12S rRNA) gene. He was made a candidate for cochlear implantation. Preoperative high-resolution computed tomography and magnetic resonance imaging of the temporal bone revealed the presence of an Arnold-Chiari malformation type I. To the best of our knowledge, this study is the second report on partial 6p trisomy that involves the 10q terminal region. Furthermore, we report the first case of documented Arnold-Chiari malformation type I and increased factor XIII activity associated with 6p trisomy. We present a comprehensive report of the familial cases and an exhaustive literature review.

HEF1 promotes epithelial mesenchymal transition and bone invasion in prostate cancer under the regulation of microRNA-145

The principal problem arising from prostate cancer (PCa) is its propensity to metastasize to bones, and it's crucial to understand the mechanism of tumor progression to metastasis in order to develop therapies that may reduce the morbidity and mortality of PCa patients. Although we had identified that microRNA(miR)-145 could repress bone metastasis of PCa via regulating epithelial-mesenchymal transition (EMT) in previous study, it is still unknown how miR-145 regulated EMT. In the present study, we constructed a luciferase reporter system and identified HEF1 as a direct target of miR-145. More importantly, HEF1 was shown to promote migration, invasion and EMT of PC-3 cells, a human PCa cell line originated from a bone metastatic PCa specimen. And HEF1 was also shown to partially mediate miR-145 suppression of EMT and invasion. Furthermore, inhibition of HEF1 repressed bone invasion of PC-3 cells in vivo. Expression of HEF1 was negatively correlated with miR-145 in primary PCa and bone metastatic specimens, but HEF1 was higher in samples which were more likely to commit to bone metastasis or those with higher free prostate-specific antigen (fPSA) levels and Gleason scores. Taken together, these findings indicate that HEF1 promotes EMT and bone invasion in prostate cancer by directly targeted by miR-145, and miR-145 suppresses EMT and invasion, at least in part, through repressing HEF1.

A requirement for Nedd9 in luminal progenitor cells prior to mammary tumorigenesis in MMTV-HER2/ErbB2 mice

Overexpression of the NEDD9/HEF1/Cas-L scaffolding protein is frequent, and drives invasion and metastasis in breast, head and neck, colorectal, melanoma, lung and other types of cancer. We have examined the consequences of genetic ablation of Nedd9 in the MMTV-HER2/ERBB2/neu mouse mammary tumor model. Unexpectedly, we found that only a limited effect on metastasis in MMTV-neu;Nedd9(-/-) mice compared with MMTV-neu;Nedd9(+/+) mice, but instead a dramatic reduction in tumor incidence (18 versus 80%), and a significantly increased latency until tumor appearance. Orthotopic reinjection and tail-vein injection of cells arising from tumors, coupled with in vivo analysis, indicated tumors arising in MMTV-neu;Nedd9(-/-) mice had undergone mutational selection that overcame the initial requirement for Nedd9. To better understand the defects in early tumor growth, we compared mammary progenitor cell pools from MMTV-neu;Nedd9(-/-) versus MMTV-neu;Nedd9(+/+) mice. The MMTV-neu;Nedd9(-/-) genotype selectively reduced both the number and colony-forming potential of mammary luminal epithelial progenitor cells, while not affecting basal epithelial progenitors. MMTV-neu;Nedd9(-/-) mammospheres had striking defects in morphology and cell polarity. All of these defects were seen predominantly in the context of the HER2/neu oncogene, and were not associated with randomization of the plane of mitotic division, but rather with depressed expression the cell attachment protein FAK, accompanied by increased sensitivity to small molecule inhibitors of FAK and SRC. Surprisingly, in spite of these significant differences, only minimal changes were observed in the gene expression profile of Nedd9(-/-) mice, indicating critical Nedd9-dependent differences in cell growth properties were mediated via post-transcriptional regulation of cell signaling. Coupled with emerging data indicating a role for NEDD9 in progenitor cell populations during the morphogenesis of other tissues, these results indicate a functional requirement for NEDD9 in the growth of mammary cancer progenitor cells.

NSP-CAS Protein Complexes: Emerging Signaling Modules in Cancer

The CAS (CRK-associated substrate) family of adaptor proteins comprises 4 members, which share a conserved modular domain structure that enables multiple protein-protein interactions, leading to the assembly of intracellular signaling platforms. Besides their physiological role in signal transduction downstream of a variety of cell surface receptors, CAS proteins are also critical for oncogenic transformation and cancer cell malignancy through associations with a variety of regulatory proteins and downstream effectors. Among the regulatory partners, the 3 recently identified adaptor proteins constituting the NSP (novel SH2-containing protein) family avidly bind to the conserved carboxy-terminal focal adhesion-targeting (FAT) domain of CAS proteins. NSP proteins use an anomalous nucleotide exchange factor domain that lacks catalytic activity to form NSP-CAS signaling modules. Additionally, the NSP SH2 domain can link NSP-CAS signaling assemblies to tyrosine-phosphorylated cell surface receptors. NSP proteins can potentiate CAS function by affecting key CAS attributes such as expression levels, phosphorylation state, and subcellular localization, leading to effects on cell adhesion, migration, and invasion as well as cell growth. The consequences of these activities are well exemplified by the role that members of both families play in promoting breast cancer cell invasiveness and resistance to antiestrogens. In this review, we discuss the intriguing interplay between the NSP and CAS families, with a particular focus on cancer signaling networks.

Novel susceptibility genes associated with diabetic cataract in a Taiwanese population

PURPOSE

To identify genetic variants that predispose to type 2 diabetes (T2D) with cataract.

PATIENTS AND METHODS

Genome-wide association study (GWAS) of T2D patients with cataract, as graded by Lens Opacities Classification System (LOCS). A total of 109 T2D patients with cataract score equal to or above 10 designated as the study group, 649 T2D patients with cataract score equal to or below 3 as the control group. Single nucleotide polymorphisms (SNPs) with p-values < 10(-5) were considered to be putatively associated with the diabetic cataract.

RESULTS

Fifteen SNPs were found to be putatively associated with diabetic cataract. These variants were located near the following genes: PPARD, CCDC102A, GBA3, NEDD9, GABRR1/2, RPS6KA2, tcag7.1163, TAC1, GALNTL1 and KIAA1671. We defined haplotype 1 to haplotype 4 from the alternative alleles of related polymorphisms. Distribution of haplotype 2 on chromosome 4 and haplotype 4 on chromosome 7 revealed significant differences (OR = 1.86 and 1.69, respectively; 95% confidence interval were 1.26-2.76 and 1.23-2.31, respectively).

CONCLUSIONS

The 15 loci coded on chromosomes 4, 6, 7, 14, 16 and 22 were associated with diabetic cataract. Gene functions are either with mechanisms of regulating blood sugar or formation of cataract. High linkage disequilibrium appeared on chromosome 4p15.31 and chromosome 7q21.3.

Augmented generation of protein fragments during wakefulness as the molecular cause of sleep: a hypothesis

Despite extensive understanding of sleep regulation, the molecular-level cause and function of sleep are unknown. I suggest that they originate in individual neurons and stem from increased production of protein fragments during wakefulness. These fragments are transient parts of protein complexes in which the fragments were generated. Neuronal Ca²⁺ fluxes are higher during wakefulness than during sleep. Subunits of transmembrane channels and other proteins are cleaved by Ca²⁺-activated calpains and by other nonprocessive proteases, including caspases and secretases. In the proposed concept, termed the fragment generation (FG) hypothesis, sleep is a state during which the production of fragments is decreased (owing to lower Ca²⁺ transients) while fragment-destroying pathways are upregulated. These changes facilitate the elimination of fragments and the remodeling of protein complexes in which the fragments resided. The FG hypothesis posits that a proteolytic cleavage, which produces two fragments, can have both deleterious effects and fitness-increasing functions. This (previously not considered) dichotomy can explain both the conservation of cleavage sites in proteins and the evolutionary persistence of sleep, because sleep would counteract deleterious aspects of protein fragments. The FG hypothesis leads to new explanations of sleep phenomena, including a longer sleep after sleep deprivation. Studies in the 1970s showed that ethanol-induced sleep in mice can be strikingly prolonged by intracerebroventricular injections of either Ca²⁺ alone or Ca²⁺ and its ionophore (Erickson et al., Science 1978;199:1219-1221; Harris, Pharmacol Biochem Behav 1979;10:527-534; Erickson et al., Pharmacol Biochem Behav 1980;12:651-656). These results, which were never interpreted in connection to protein fragments or the function of sleep, may be accounted for by the FG hypothesis about molecular causation of sleep.

The CRTC1-NEDD9 signaling axis mediates lung cancer progression caused by LKB1 loss

Somatic mutation of the tumor suppressor gene LKB1 occurs frequently in lung cancer where it causes tumor progression and metastasis, but the underlying mechanisms remain mainly unknown. Here, we show that the oncogene NEDD9 is an important downstream mediator of lung cancer progression evoked by LKB1 loss. In de novo mouse models, RNAi-mediated silencing of Nedd9 inhibited lung tumor progression, whereas ectopic NEDD9 expression accelerated this process. Mechanistically, LKB1 negatively regulated NEDD9 transcription by promoting cytosolic translocation of CRTC1 from the nucleus. Notably, ectopic expression of either NEDD9 or CRTC1 partially reversed the inhibitory function of LKB1 on metastasis of lung cancer cells. In clinical specimens, elevated expression of NEDD9 was associated with malignant progression and metastasis. Collectively, our results decipher the mechanism through which LKB1 deficiency promotes lung cancer progression and metastasis, and provide a mechanistic rationale for therapeutic attack of these processes.

Overexpression and cytoplasmic accumulation of Hepl is associated with clinicopathological parameters and poor prognosis in non-small cell lung cancer

Hepl, first described in 2008, is the fourth member of the Crk-associated substrate (CAS) family and is specifically expressed in the lung. Compared to other CAS proteins, Hepl has a varying effect on cell migration in different cell types. We speculated that Hepl may play a role in lung cancer invasion and metastasis. We quantified the expression and subcellular localization of Hepl in 143 non-small cell lung cancer (NSCLC) tissues, adjacent noncancerous tissues, and eight lung cancer cell lines using Western blotting, immunohistochemistry, and immunofluorescent staining. Expression of Hepl was correlated with the clinicopathological features of NSCLC. Hepl was overexpressed in 72.3 % (103/143) of the NSCLC tissues, compared to the adjacent noncancerous lung tissues (P = 0.022). Overexpression of Hepl was associated with lymph node metastasis and high TNM stage (P = 0.005 and P = 0.045, respectively). Kaplan-Meier survival curves and the log-rank test indicated that overexpression of Hepl correlated with poorer overall survival in NSCLC (P < 0.001), and Cox regression analysis demonstrated that overexpression of Hepl was an independent prognostic factor in NSCLC. Furthermore, cytoplasmic accumulation of Hepl was observed in a high metastatic potential lung cancer cell lines (H1299 and BE1), but not in low metastatic potential cell lines (LTE and A549). This study reveals that Hepl is overexpressed in the nucleus and aberrantly accumulates in the cytoplasm of NSCLC cells, and indicates that Hepl may play a role in the progression of lung cancer, including lymph node metastasis and TNM stage. Additionally, Hepl may be a useful prognostic factor in lung cancer.

The extracellular matrix and ciliary signaling

The primary cilium protrudes like an antenna from the cell surface, sensing mechanical and chemical cues provided in the cellular environment. In some tissue types, ciliary orientation to lumens allows response to fluid flow; in others, such as bone, ciliary protrusion into the extracellular matrix allows response to compression forces. The ciliary membrane contains receptors for Hedgehog, Wnt, Notch, and other potent growth factors, and in some instances also harbors integrin and cadherin family members, allowing receipt of a robust range of signals. A growing list of ciliopathies, arising from deficient formation or function of cilia, includes both developmental defects and chronic, progressive disorders such as polycystic kidney disease (PKD); changes in ciliary function have been proposed to support cancer progression. Recent findings have revealed extensive signaling dialog between cilia and extracellular matrix (ECM), with defects in cilia associated with fibrosis in multiple contexts. Further, a growing number of proteins have been determined to possess multiple roles in control of cilia and focal adhesion interactions with the ECM, further coordinating functionality. We summarize and discuss these recent findings.

Traditional Chinese medicine as dual guardians against hypertension and cancer?

This study utilizes the comprehensive traditional Chinese medicine database TCM Database@Taiwan ( http://tcm.cmu.edu.tw/ ) in conjunction with structure-based and ligand-based drug design to identify multi-function Src inhibitors. The three potential TCM candidates identified as having suitable docking conformations and bioactivity profiles were Angeliferulate, (3R)-2'-hydroxy-3',4'-dimethoxyisoflavan-7-O-beta-D-glucoside (HMID), and 3-[2',6-dihydroxy-5'-(2-propenyl)[1,1'-biphenyl]3-yl]-(E)-2-propenoic acid (3PA). Molecular dynamics simulation demonstrated that the TCM candidates have more stable interactions with the cleft and in complex with Src kinase compared to Saracatinib. Angeliferulate and HMID, both originated from Angelica sinensis, not only interact with Lys298 and amino acids from different loops in the cleft, but also with Asp407 located on the activation loop. These interactions are important to reduce the opening of the activation loop due to phosphorylation, hence stabilize the Src kinase cleft structure and inhibit activation. The TCM candidates also exhibited high affinity to other cancer-related target proteins (EGFR, HER2, and HSP90). Our observations suggest that the TCM candidates might have multi-targeting effects in hypertension and cancer.

The aryl hydrocarbon receptor regulates focal adhesion sites through a non-genomic FAK/Src pathway

The aryl hydrocarbon receptor (AhR) is commonly described as a transcription factor, which regulates xenobiotic-metabolizing enzymes. Recent studies have suggested that the binding of ligands to the AhR also activates the Src kinase. In this manuscript, we show that the AhR, through the activation of Src, activates focal adhesion kinase (FAK) and promotes integrin clustering. These effects contribute to cell migration. Further, we show that the activation of the AhR increases the interaction of FAK with the metastatic marker, HEF1/NEDD9/CAS-L, and the expression of several integrins. Xenobiotic exposure, thus, may contribute to novel cell-migratory programs.

Cas and NEDD9 Contribute to Tumor Progression through Dynamic Regulation of the Cytoskeleton

The Cas family proteins, p130(Cas) (Cas) and NEDD9, are adaptor molecules that regulate cytoskeletal dynamics to promote multiple cellular processes, including migration, invasion, proliferation, and survival. Because these functions are also critical for tumor initiation, growth, and metastasis, Cas and NEDD9 are well positioned to contribute to these oncogenic processes. Indeed, mouse models of cancer show that these proteins function during multiple stages of disease progression. Furthermore, in many human cancers, high expression of Cas and NEDD9 is associated with advanced stage disease and is predictive of poor outcome. This review explores the contribution of Cas and NEDD9 during cellular transformation and neoplastic growth, tumor progression, metastasis, and the development of therapeutic resistance. Given these roles, Cas and NEDD9 may prove to be viable candidates for use as biomarkers and therapeutic targets.

E-cadherin cell-cell communication in melanogenesis and during development of malignant melanoma

Cell-cell communication is necessary for the crosstalk between cells that constitute multicellular organisms and is essential for cells to coordinate their physiological behavior to create cohesive tissues. Cellular crosstalk is not only controlled by molecules, like growth factors, hormones, ions and G-proteins, etc. but also by cell-cell contacts. These contacts are essential for intercellular communication and are involved in survival, apoptosis, proliferation, differentiation and homeostasis of entire tissues. In polarized epithelia of vertebrates, the adherent junction is part of the tripartite junctional complex that is localized at the juxtaluminal region, which includes tight junctions (including claudins, occludins, and zonula occludens proteins), desmosomal junctions (including desmogleins), and adherent junctions. In focus of the manuscript are adherent molecules of the cadherin superfamily of the skin. In the normal epidermis, melanocytes and keratinocytes are mostly connected via E-cadherin, P-cadherin and H-cadherin [1-3]. Melanocytes that reside in the basal layer of the epidermis predominantly contain E-cadherin and H-cadherin, whereas those that reside in the hair follicles are rich in P-cadherin [2]. The regulation and role of E-cadherin during melanoma development will be the focus of this review.