JWA regulates melanoma metastasis by integrin alphaVbeta3 signaling

JWA inhibits nicotine-induced lung cancer stemness and progression through CHRNA5/AKT-mediated JWA/SP1/CD44 axis

Cigarette smoking is an independent risk factor for lung cancer. Nicotine, as an addictive substance in tobacco and e-cigarettes, is known to promote tumor progression and metastasis despite being a non-carcinogen. As a tumor suppressor gene, JWA is widely involved in the inhibition of tumor growth and metastasis and the maintenance of cellular homeostasis, including in non-small cell lung cancer (NSCLC). However, the role of JWA in nicotine-induced tumor progression remains unclear. Here, we reported for the first time that JWA was significantly downregulated in smoking-related lung cancer and associated with overall survival. Nicotine exposure reduced JWA expression in a dose-dependent manner. Gene Set Enrichment Analysis (GSEA) analysis showed the tumor stemness pathway was enriched in smoking-related lung cancer, and JWA was negatively associated with stemness molecules CD44, SOX2, and CD133. JWA also inhibited nicotine-enhanced colony formation, spheroid formation, and EDU incorporation in lung cancer cells. Mechanically, nicotine downregulated JWA expression via the CHRNA5-mediated AKT pathway. Lower JWA expression enhanced CD44 expression through inhibition of ubiquitination-mediated degradation of Specificity Protein 1 (SP1). The in vivo data indicated that JAC4 through the JWA/SP1/CD44 axis inhibited nicotine-triggered lung cancer progression and stemness. In conclusion, JWA via down-regulating CD44 inhibited nicotine-triggered lung cancer cell stemness and progression. Our study may provide new insights to develop JAC4 for the therapy of nicotine-related cancers.

JAC4 Inhibits EGFR-Driven Lung Adenocarcinoma Growth and Metastasis through CTBP1-Mediated JWA/AMPK/NEDD4L/EGFR Axis

Lung adenocarcinoma (LUAD) is the most common lung cancer, with high mortality. As a tumor-suppressor gene, JWA plays an important role in blocking pan-tumor progression. JAC4, a small molecular-compound agonist, transcriptionally activates JWA expression both in vivo and in vitro. However, the direct target and the anticancer mechanism of JAC4 in LUAD have not been elucidated. Public transcriptome and proteome data sets were used to analyze the relationship between JWA expression and patient survival in LUAD. The anticancer activities of JAC4 were determined through in vitro and in vivo assays. The molecular mechanism of JAC4 was assessed by Western blot, quantitative real-time PCR (qRT-PCR), immunofluorescence (IF), ubiquitination assay, co-immunoprecipitation, and mass spectrometry (MS). Cellular thermal shift and molecule-docking assays were used for confirmation of the interactions between JAC4/CTBP1 and AMPK/NEDD4L. JWA was downregulated in LUAD tissues. Higher expression of JWA was associated with a better prognosis of LUAD. JAC4 inhibited LUAD cell proliferation and migration in both in-vitro and in-vivo models. Mechanistically, JAC4 increased the stability of NEDD4L through AMPK-mediated phosphorylation at Thr367. The WW domain of NEDD4L, an E3 ubiquitin ligase, interacted with EGFR, thus promoting ubiquitination at K716 and the subsequent degradation of EGFR. Importantly, the combination of JAC4 and AZD9191 synergistically inhibited the growth and metastasis of EGFR-mutant lung cancer in both subcutaneous and orthotopic NSCLC xenografts. Furthermore, direct binding of JAC4 to CTBP1 blocked nuclear translocation of CTBP1 and then removed its transcriptional suppression on the JWA gene. The small-molecule JWA agonist JAC4 plays a therapeutic role in EGFR-driven LUAD growth and metastasis through the CTBP1-mediated JWA/AMPK/NEDD4L/EGFR axis.

PRAF2 is an oncogene acting to promote the proliferation and invasion of breast cancer cells

Prenylated rab acceptor 1 domain family member 2 (PRAF2) acts as an oncogene and is closely related to the occurrence and development of various tumors. The present study aimed to clarify the functional relevance of PRAF2 in the biological behaviors of breast cancer by determining the expression of PRAF2 in breast cancer tissues and the corresponding adjacent tissues. The gene phenotypes of PRAF2 in patients with breast cancer in The Cancer Genome Atlas database were predicted using a cancer data online analysis website: The University of Alabama at Birmingham Cancer Data Analaysis Portal (UALCAN). The mRNA and protein expression of PRAF2 was further examined in 37 pairs of fresh frozen breast cancer tissues and adjacent non-tumor tissues by reverse transcription-quantitative PCR (RT-qPCR) and western blotting. High expression of PRAF2 was verified by RT-qPCR in the breast cancer cell line, MCF-7, and small interfering RNA (siRNA) technology was used to silence PRAF2. In the in vitro cell functional experiment, three groups were used: Negative control (NC) group, siRNA-NC group and siRNA-PRAF2 group. Cell Counting Kit-8 (CCK-8) and colony formation assays were conducted to analyze the effect of downregulation of PRAF2 on the proliferation of breast cancer cells. Transwell invasion and cell scratch assays were performed to examine the effect of downregulation of PRAF2 on the invasion and migration of breast cancer cells. UALCAN analysis results indicated that PRAF2 expression was upregulated in breast cancer compared with normal tissue samples (P<0.001). High expression of PRAF2 in breast cancer was associated with TNM stage and regional lymph node metastasis. RT-qPCR results showed increased mRNA expression of PRAF2 in clinical tissue samples from 37 patients with breast cancer, compared with normal adjacent tissues (P<0.001). Protein expression of PRAF2 was also shown to be higher in the breast cancer MCF-7 cells than in the MDA-MB-231 cells. Western blotting analysis combined with ImageJ software quantification showed that the relative expression of PRAF2 protein was significantly higher in clinical tissue samples from 37 patients with breast cancer (1.9750±0.0103) than that in normal adjacent tissues (0.9818±0.0140) (P<0.001). Western blotting analysis results indicated that transfection with siRNA PRAF2 in MCF-7 cells decreased PRAF2 expression (P<0.001). The results of CCK-8 and colony formation assays revealed that downregulation of PRAF2 expression suppressed the proliferation of MCF-7 cells (P<0.05 and P<0.001, respectively). In addition, Transwell invasion and cell scratch assay results showed that downregulation of PRAF2 expression in MCF-7 cells repressed invasion and migration of cancer cells (P<0.001). Overall, PRAF2 expression was significantly higher in breast cancer tissues than normal adjacent tissues, and was closely related to TNM stage and regional lymph node metastasis in breast cancer. PRAF2 was found to act as an oncogene that is able to promote breast cancer cell proliferation and invasion. Thus, PRAF2 may be a potential prognostic factor in patients with breast cancer and a potential target for the treatment of breast cancer metastasis.

Targeting JWA for Cancer Therapy: Functions, Mechanisms and Drug Discovery

Simple Summary

JWA has been identified as a potential therapeutic target for several cancers. In this review, we summarize the tumor suppressive functions of the JWA gene and its role in anti-cancer drug development. The focus is on elucidating the key regulatory proteins up and downstream of JWA and their signaling networks. We also discuss current strategies for targeting JWA (JWA peptides, small molecule agonists, and JWA-targeted Pt (IV) prodrugs).

Abstract

Tumor heterogeneity limits the precision treatment of targeted drugs. It is important to find new tumor targets. JWA, also known as ADP ribosylation factor-like GTPase 6 interacting protein 5 (ARL6IP5, GenBank: AF070523, 1998), is a microtubule-associated protein and an environmental response gene. Substantial evidence shows that JWA is low expressed in a variety of malignancies and is correlated with overall survival. As a tumor suppressor, JWA inhibits tumor progression by suppressing multiple oncogenes or activating tumor suppressor genes. Low levels of JWA expression in tumors have been reported to be associated with multiple aspects of cancer progression, including angiogenesis, proliferation, apoptosis, metastasis, and chemotherapy resistance. In this review, we will discuss the structure and biological functions of JWA in tumors, examine the potential therapeutic strategies for targeting JWA and explore the directions for future investigation.

JAC4 Protects from X-Ray Radiation-Induced Intestinal Injury by JWA-Mediated Anti-Oxidation/Inflammation Signaling

Radiation-induced intestinal injury is one of the major side effects in patients receiving radiation therapy. There is no specific treatment for radiation-induced enteritis in the clinic. We synthesized a compound, named JAC4, which is an agonist and can increase JWA protein expression. JWA has been shown to reduce oxidative stress, DNA damage, anti-apoptosis, and anti-inflammatory; in addition, the small intestine epithelium showed dysplasia in JWA knockout mice. We hypothesized that JAC4 might exert a protective effect against radiation-induced intestinal damage. Herein, X-ray radiation models were built both in mice and in intestinal crypt epithelial cells (IEC-6). C57BL/6J mice were treated with JAC4 by gavage before abdominal irradiation (ABI); the data showed that JAC4 significantly reduced radiation-induced intestinal mucosal damage and increased the survival rate. In addition, radiation-induced oxidative stress damage and systemic inflammatory response were also mitigated by JAC4 treatment. Moreover, JAC4 treatment alleviated DNA damage, decreased cell apoptosis, and maintained intestinal epithelial cell proliferation in mice. In vitro data showed that JAC4 treatment significantly inhibited ROS formation and cell apoptosis. Importantly, all the above protective effects of JAC4 on X-ray radiation-triggered intestinal injury were no longer determined in the intestinal epithelium of JWA knockout mice. Therefore, our results provide the first evidence that JAC4 protects the intestine from radiation-induced enteritis through JWA-mediated anti-oxidation/inflammation signaling.

ARL6IP5 reduces cisplatin-resistance by suppressing DNA repair and promoting apoptosis pathways in ovarian carcinoma

Ovarian carcinoma (OC) is the most lethal gynecological malignancy due to frequent recurrence resulting from cisplatin-resistance. ARL6IP5 is a novel gene implicated to suppress cisplatin-resistance by activating apoptosis and inhibiting DNA repair through XRCC1 and PARP1. We investigated the clinicopathological and prognostic significance of the immunohistochemical ARL6IP5 expression on 79 post-chemotherapy OC patient tissue samples; in vitro, the effect of ARL6IP5 overexpression (OE) and knockdown (KD) on cancer hallmark functions and the effect of ARL6IP5 on the expression of DNA repair and apoptosis-related proteins were observed in OC cells and their cisplatin-resistant (CisR) counterparts. ARL6IP5 expression was significantly associated with chemotherapeutic response and was an independent prognosticator of progression-free and overall survival of high-grade serous OC patients. ARL6IP5-OE decreased cellular proliferation, invasion, migration, adhesion, and increased apoptosis (p < 0.05); the opposite was observed for ARL6IP5-KD. Notably, ARL6IP5-OE reduced cisplatin-resistance of both OC and CisR OC cells, while ARL6IP5-KD increased cisplatin-resistance (p < 0.05). ARL6IP5-OE suppressed the expressions of DNA repair proteins and increased those of pro-apoptotic proteins; the opposite was observed for ARL6IP5-KD. The recombinant ARL6IP5 protein (rARL6IP5) had the greatest apoptotic effect among cisplatin and olaparib, in both OC and CisR OC cells; moreover, rARL6IP5 was the only single agent in CisR OC cells to retain higher apoptotic efficacy compared with control (p < 0.05), indicating that the apoptotic pathway influenced by rARL6IP5 remained effective in CisR OC cells compared to cisplatin and olaparib. In conclusion, we demonstrated that ARL6IP5 is an independent prognosticator of OC patients with cellular functions of a tumor-suppressor, possibly influencing the development of cisplatin-resistance and progression of OC cells through regulation of DNA repair and apoptosis. rARL6IP5 had significantly greater apoptotic efficacy compared to conventional chemotherapeutic agents in both OC and CisR OC cells, suggesting that ARL6IP5 may be a valuable novel chemotherapeutic against CisR OC.

JAC1 suppresses proliferation of breast cancer through the JWA/p38/SMURF1/HER2 signaling

The overexpression of HER2 is associated with a malignant proliferation of breast cancer. In this study, we developed a non-cytotoxic JWA gene activating compound 1 (JAC1) to inhibit the proliferation of HER2-positive breast cancer cells in vitro and in vivo experimental models. JAC1 increased the ubiquitination of HER2 at the K716 site through the E3 ubiquitin ligase SMURF1 which was due to the decreased expression of NEDD4, the E3 ubiquitin ligase of SMURF1. In conclusion, JAC1 suppresses the proliferation of HER2-positive breast cancer cells through the JWA triggered HER2 ubiquitination signaling. JAC1 may serve as a potential therapeutic agent for HER2-positive breast cancer.

Implication of integrins α3β1 and α5β1 in invasion and anoikis of SK-Mel-147 human melanoma cells: non-canonical functions of protein kinase Akt

Downregulation of integrins α3β1 and α5β1 strongly decreased cell colony formation and in vitro invasion and markedly enhanced anoikis in SK-Mel-147 human melanoma cells. These modifications were accompanied by a marked increase in the levels of active Akt protein kinase, which indicated it played a non-canonical function in the melanoma cells. Pharmacological inhibition of Akt1, an Akt isozyme, in cells depleted of α3β1 or α5β1 restored their invasive activity, while inhibition of the Akt 2 isoform did not cause a visible effect. Similar to our previous results with the α2β1 integrin, this finding suggested that in signaling pathways initiated by α3β1 and α5β1, the Akt1 isoform performs a non-canonical function in regulating invasive phenotype of melanoma cells. In contrast, when the effects of Akt inhibitors on anoikis of the melanoma cells were compared, the Akt2 isoform demonstrated a non-canonical activity in which Akt2 suppression led to a significant attenuation of apoptosis in cells with downregulated α3β1 or α5β1. Our results were the first evidence that, in the same tumor cells, different integrins can control various manifestations of tumor progression through distinct signaling pathways that are both common to various integrins and specific to a particular receptor.

JP1 suppresses proliferation and metastasis of melanoma through MEK1/2 mediated NEDD4L-SP1-Integrin αvβ3 signaling

Background: JWA gene is known to down-regulate SP1 and reduces the expression level of Integrin αvβ3. Here, we identified a functional polypeptide (JP1) based on the active fragment of the JWA protein to suppress melanoma growth and metastasis by inhibiting the Integrin αvβ3. Methods: We conducted a series of melanoma growth and metastasis mouse models to evaluate anti-melanoma effect of JP1 peptide. 18F-labeled JP1 (18F-NFP-JP1) was detected by Micro-PET assay to demonstrate drug biodistribution. Toxicity test in cynomolgus monkeys and pharmacokinetic studies in rats were done to assess the druggability. The expression of MEK1/2, NEDD4L, SP1 and Integrin αvβ3 were detected in vitro and vivo models. Results: The peptide JP1 with the best anticancer effect was obtained. Micro-PET assay showed that JP1 specifically targeting to melanoma cells in vivo. JP1 inhibited melanoma growth, metastasis, and prolonged the survival of mouse. JP1 reduced the dosage and toxicity in combination with DTIC in melanoma xenograft and allograft mouse models. Cynomolgus monkey toxicity test showed no observed adverse effect level (NOAEL) of JP1 was 150 mg/kg. Mechanistically, JP1 was shown to activate p-MEK1/2 and triggered SP1 ubiquitination in melanoma cells. NEDD4L, an E3 ubiquitin ligase, was activated by p-MEK1/2 and to ubiquitinate SP1 at K685 site, resulting in subsequent degradation. Conclusions: JP1 was developed as a novel peptide that indicated therapeutic roles on proliferation and metastasis of melanoma through the NEDD4L-SP1-Integrin αvβ3 signaling.

JP3, an antiangiogenic peptide, inhibits growth and metastasis of gastric cancer through TRIM25/SP1/MMP2 axis

BACKGROUND

Gastric cancer (GC) is the most prevalent gastrointestinal tumor with an unfavorable clinical prognosis. GC patients are largely threatened owing to metastasis and drug resistance. Tumor angiogenesis plays an important role in the development of gastric cancer and is a challenge in the treatment of gastric cancer.

METHODS

Mouse xenograft models were used for screening of therapeutic peptides on GC growth and metastasis. Routine laboratory experimental methods including conditional cell culture, tube formation assay, qRT-PCR, Western blotting, immunohistochemistry (IHC), ubiquitination assay, and immunofluorescence (IF) were used in mechanism investigation; protein docking analysis and coimmunoprecipitation (Co-IP) were used for prediction and confirmation of interactions between JP3/SP1 and TRIM25/MEK1/2.

RESULTS

We identified an MMP2-targeted peptide JP3 that plays inhibiting roles in modulating growth and metastasis of GC in vivo and has no observable toxic side effects. JP3 reduced tumor microvessel density (MVD) in vivo and human umbilical vein endothelial cells (HUVECs) tube formation in vitro. Mechanistic studies revealed that JP3 reduces polyubiquitination-mediated degradation of TRIM25 by increasing the stability of TRIM25 through phosphorylating it at Ser12. TRIM25, as an E3 ubiquitin ligase, promoted the ubiquitin of SP1 at K610, further suppressed expression of MMP2 and inhibited angiogenesis in GC. Importantly, the inversely association between TRIM25 and SP1 protein level was further verified in human GC tissues. Decreased TRIM25 expression and increased SP1 expression in tumor tissues were positively correlated with poor prognosis of GC patients.

CONCLUSIONS

MMP2-targeted peptide JP3 plays a therapeutic role in GC through anti-angiogenesis by modulating TRIM25/SP1/MMP2.

PRAF2 overexpression predicts poor prognosis and promotes tumorigenesis in esophageal squamous cell carcinoma

BACKGROUND

Prenylated Rab acceptor 1 domain family, member 2 (PRAF2) is involved in the occurrence and progression of several malignant tumors. However, its potential role in esophageal squamous cell carcinoma (ESCC) is still unknown.

METHODS

PRAF2 mRNA expression was determined in 77 frozen ESCC samples by quantitative reverse transcription-polymerase chain reaction (qPCR) and its association with clinical features and overall survival were evaluated. The roles of PRAF2 in ESCC cells were investigated by proliferation, cell cycle, invasion and apoptosis assays in vitro.

RESULTS

The PRAF2 mRNA expression was significantly increased in ESCC tissues compared with matched surrounding non-tumor tissues. Survival analysis showed that high PRAF2 mRNA expression was associated with worse overall survival in ESCC patients. Multivariate analysis revealed that PRAF2 (hazard ratio 2.05, 95% CI 1.10-3.85, P = 0.025) emerged as the independent predictor for poor overall survival in ESCC. The in vitro experiments revealed that knockdown of PRAF2 expression blocked cell proliferation, cell cycle progression and cell invasion and induced cell apoptosis in ESCC cells.

CONCLUSION

Taken together, our data demonstrate that PRAF2 could be used as a potential prognostic biomarker and represent a potential therapeutic target for ESCC.

Implication of integrin α2β1 in anoikis of SK-Mel-147 human melanoma cells: a non-canonical function of Akt protein kinase

Suppression of anoikis, a kind of apoptosis caused by disruption of contacts between cell and extracellular matrix, is an important prerequisite for cancer cell metastasis. In this communication, we demonstrate that shRNA-mediated depletion of α2 integrin subunit induces anoikis and substantially decreases colony-forming potential in SK-Mel-147 human melanoma cells. Suppression of α2β1 upregulates the levels of pro-apoptotic protein p53 and cyclin-dependent kinase inhibitors p21 and p27. Concomitantly, we detected decrease in the levels of anti-apoptotic protein Bcl-2 and cell cycle regulator c-Myc. Moreover, depletion of α2β1 reduces the activity of protein kinase Erk, while increases activity of Akt kinase. Pharmacological inhibition of P3IK kinase, an upstream activator of Akt, greatly enhanced anoikis in control cells while reduced that in cells with decreased levels of α2β1. Of three isoforms of Akt, down-regulation of Akt1 greatly diminished anoikis of cells depleted of α2β1, while down-regulation of Akt2 and Akt3 sharply increased anoikis in these cells. These findings were supported by the data of pharmacological inhibition of the Akt isoforms. Our results demonstrate for the first time that anoikis induced by α2β1 integrin knockdown can be attenuated by Akt1 inhibition.

Implication of Integrin α2β1 in Proliferation and Invasion of Human Breast Carcinoma and Melanoma Cells: Noncanonical Function of Akt Protein Kinase

Blocking the expression of integrin α2β1, which was accomplished by transduction of α2-specific shRNA, resulted in significant inhibition of proliferation and clonal activity in human MCF-7 breast carcinoma and SK-Mel-147 melanoma cells. Along with these changes, deprivation of α2β1 caused a sharp decrease in melanoma cell invasion in vitro. Analysis of integrin-mediating signal pathways that control cell behavior revealed a significant increase in activity of Akt protein kinase in response to depletion of α2β1. The increase in Akt activity that accompanies a suppressive effect on cell invasion contradicts well-known Akt function aimed at stimulation of tumor progression. This contradiction could be explained by the "reversed" (noncanonical) role played by Akt in some cells that consists in suppression rather than promotion of invasive phenotype. To test this suggestion, the effects of Akt inhibitors on invasive activity of SK-Mel-147 cells were investigated. If the above suggestion is true, then inhibition of Akt in cells depleted of α2β1 should result in the restoration of their invasive activity. It appeared that treatment with LY294002, which inhibits all Akt isoforms (Akt1, Akt2, Akt3), not only failed to restore the invasive phenotype of melanoma cells but further attenuated their invasive activity. However, treatment of the cells with an Akt1-specific inhibitor significantly increased their invasion. Thus, the stimulating effect of α2β1 integrin on invasion of melanoma cells is realized through a mechanism based on inhibition of one of the Akt isoforms, which in these cells exhibits a noncanonical function consisting in suppression of invasion.

Integrins as therapeutic targets in the organ-specific metastasis of human malignant melanoma

Integrins are a large family of adhesion molecules that mediate cell-cell and cell-extracellular matrix interactions. Among the 24 integrin isoforms, many have been found to be associated with tumor angiogenesis, tumor cell migration and proliferation, and metastasis. Integrins, especially αvβ3, αvβ5 and α5β1, participate in mediating tumor angiogenesis by interacting with the vascular endothelial growth factor and angiopoietin-Tie signaling pathways. Melanoma patients have a poor prognosis when the primary tumor has generated distant metastases, and the melanoma metastatic site is an independent predictor of the survival of these patients. Different integrins on the melanoma cell surface preferentially direct circulating melanoma cells to different organs and promote the development of metastases at specific organ sites. For instance, melanoma cells expressing integrin β3 tend to metastasize to the lungs, whereas those expressing integrin β1 preferentially generate lymph node metastases. Moreover, tumor cell-derived exosomes which contain different integrins may prepare a pre-metastatic niche in specific organs and promote organ-specific metastases. Because of the important role that integrins play in tumor angiogenesis and metastasis, they have become promising targets for the treatment of advanced cancer. In this paper, we review the integrin isoforms responsible for angiogenesis and organ-specific metastasis in malignant melanoma and the inhibitors that have been considered for the future treatment of metastatic disease.

JWA suppresses the invasion of human breast carcinoma cells by downregulating the expression of CXCR4

Breast cancer is the second leading cause of cancer-associated mortality, and metastatic breast cancer is responsible for 90% of patient mortalities. Given that JWA represses the proliferation, invasion and metastasis of a number of other human tumor cells, including melanoma, esophageal, hepatocellular and gastric carcinomas, via mitogen-activated protein kinase or integrin signaling, the present study investigated the expression and function of JWA in human breast cancers. The results showed that the expression level of JWA was significantly reduced in human primary breast cancers when compared with the paired adjacent tissues. Downregulating JWA enhanced, while overexpressing JWA suppressed, the migration and invasion abilities of the two breast cancer cell lines, MDA-MB-468 and MDA-MB-231, without affecting their proliferations in vitro. In addition, JWA negatively regulated the surface expression of CXCR4 in the two cell lines via proteasome degradation, though not via transcriptional inhibition. Functionally, normalizing the disturbed expressions of CXCR4 largely reversed the inhibitory effect of JWA on cell invasion. These data demonstrated that JWA suppressed the migration/invasion of breast carcinoma cells by downregulating the expression of CXCR4, and suggested that JWA may harbor prognostic and therapeutic potential in patients with breast cancer.

JWA deficiency induces malignant transformation of murine embryonic fibroblast cells

The present study aimed to investigate the effects of JWA knockout (JWA^-/-) on malignant transformation of murine embryonic fibroblast (MEF) cells using a conditional JWA^-/- mouse model. Once MEF cells were prepared, the potential role of JWA^-/- on proliferation, migration, invasion and colony formation of MEF cells was investigated by cytological examination. The effects of JWA^-/- on the regulation and protein expression levels of epithelial-mesenchymal transition (EMT)-related proteins in MEF cells, including poly(ADP-ribose) polymerase-1 (PARP-1), vimentin, β-catenin and E-cadherin, were investigated using western blot analysis. The tumorigenicity of JWA deficiency was explored using nude mouse xenografts and subcutaneous inoculation of MEF cells exhibiting JWA^-/-. JWA^-/- was able to increase cell proliferation, migration, invasion and colony formation in the malignant transformation of MEF cells. The protein expression levels of PARP-1, vimentin and β-catenin were upregulated, whereas E-cadherin was downregulated in JWA^-/- MEF cells. The tumor formation was observed in mice following subcutaneous inoculation of MEF with JWA^-/-, whereas no tumor was formed in the mice treated with functional JWA MEF cells. In conclusion, the present findings suggest that JWA^-/- has important roles in cell proliferation, migration, invasion and colony formation and is able to induce the malignant transformation of MEF cells. The expression levels of EMT-related proteins changed and tumorigenicity increased in JWA^-/- MEF cells compared with cells with functional JWA. The present findings indicate that JWA may function as an anti-oncogene in tumorigenesis.

MiR-7a is an important mediator in Fas-associated protein with death domain (FADD)-regulated expression of focal adhesion kinase (FAK)

Fas-associated protein with death domain (FADD), a classical adaptor protein mediating apoptotic stimuli-induced cell death, has been reported to engage in several non-apoptotic processes such as T cell and cardiac development and tumorigenesis. Recently, there are several reports about the FADD's involvement in cell migration, however the underlying mechanism remains elusive. Here, we present a new finding that FADD could regulate the expression of FAK, a non-receptor protein tyrosine kinase overexpressed in many cancers, and played an important role in cell migration in murine MEF and melanoma cells with different metastatic potential, B16F10 and B16F1. Moreover, miR-7a, a tumor suppressor which prohibits cell migration and invasion, was up-regulated in FADD-deficient cells. And FAK was verified to be the direct target gene of miR-7a in B16F10 cells. Furthermore, we demonstrate that miR-7a was a necessary mediator in FADD-regulated FAK expression. In contrast to its classical apoptotic role, FADD interference could reduce the rate of cell migration, which could be rescued by inhibiting miR-7a expression. Taken together, our data provide a novel explanation regarding how FADD regulates cell migration in murine melanoma cells.

A multigene support vector machine predictor for metastasis of cutaneous melanoma

Gene expression profiles of cutaneous melanoma were analyzed to identify critical genes associated with metastasis. Two gene expression datasets were downloaded from Gene Expression Omnibus (GEO) and another dataset was obtained from The Cancer Genome Atlas (TCGA). Differentially expression genes (DEGs) between metastatic and non‑metastatic melanoma were identified by meta‑analysis. A protein‑protein interaction (PPI) network was constructed for the DEGs using information from BioGRID, HPRD and DIP. Betweenness centrality (BC) was calculated for each node in the network and the top feature genes ranked by BC were selected to construct the support vector machine (SVM) classifier using the training set. The SVM classifier was then validated in another independent dataset. Pathway enrichment analysis was performed for the feature genes using Fisher's exact test. A total of 798 DEGs were identified and a PPI network including 337 nodes and 466 edges was then constructed. Top 110 feature genes ranked by BC were included in the SVM classifier. The prediction accuracies for the three datasets were 96.8, 100 and 94.4%, respectively. A total of 11 KEGG pathways and 13 GO biological pathways were significantly over‑represented in the 110 feature genes, including endometrial cancer, regulation of actin cytoskeleton, focal adhesion, ubiquitin mediated proteolysis, regulation of apoptosis and regulation of cell proliferation. A SVM classifier of high prediction accuracy was acquired. Several critical genes implicated in melanoms metastasis were also revealed. These results may advance understanding of the molecular mechanisms underlying metastasis, and also provide potential therapeutic targets.

JWA loss promotes cell migration and cytoskeletal rearrangement by affecting HER2 expression and identifies a high-risk subgroup of HER2-positive gastric carcinoma patients

Background and Aims

JWA, a microtubule-associated protein (MAP) involved in apoptosis, has been identified as a suppressor of metastasis, and it affects cell migration in melanoma and its downregulation in tumor is an idependent negative prognostic factor in resectable gastric cancer. HER2 overexpression has been observed in gastric cancer (GC) cells and implicated in the metastatic phenotype. However, the biological role of JWA in migration and its clinical value in HER2-positive GC remain elusive.

Results

JWA suppresses EGF-induced cell migration and actin cytoskeletal rearrangement by abrogating HER2 expression and downstream PI3K/AKT signaling in HER2-overexpressing GC cell lines. The modulation of HER2 by JWA is dependent on ERK activation and consequent PEA3 upregulation and activation. Reduced JWA expression is associated with high HER2 expression and with poor survival in patients with AGC, whereas HER2 expression alone is not associated with survival. However, concomitant low JWA and high HER2 expression is associated with unfavorable outcomes. Additionally, when patients were stratified by JWA expression, those with higher HER2 expression in the low JWA expression subgroup exhibited worse survival.

Methods

The impact of JWA on the EGF-induced migration of HER2-positive GC cells was studied using transwell assays and G-LISA assays. Western blotting, real-time PCR, electrophoretic mobility shift assays and luciferase assays were utilized to investigate the mechanisms by which JWA affects HER2. The association of JWA with HER2 and its clinical value were further analyzed by IHC in 128 pairs of advanced gastric cancer (AGC) and adjacent normal tissue samples.

Conclusions

This study characterizes a novel mechanism for regulating cell motility in HER2-overexpressing GC cells involving JWA-mediated MEK/ERK/PEA3 signaling activation and HER2 downregulation. Furthermore, JWA may be a useful prognostic indicator for advanced GC and may help stratify HER2-positive patient subgroups to better identify unfavorable outcomes.

Sulfatide interacts with and activates integrin αVβ3 in human hepatocellular carcinoma cells

Integrin αVβ3 is a malignant driver of anchorage-independence and tumor angiogenesis, but its dysregulation in hepatocellular carcinoma (HCC) remains unclear. In this study, we observed that sulfatide significantly promoted integrin αV(ITGAV) expression and wound closure in HCC. We also noted that elevated sulfatide profoundly stimulated integrin αVβ3 clustering and signaling. In the cells with integrin αVβ3 clustering induced by sulfatide, integrin β3 subunit was phosphorylated. Simultaneously, focal adhesion kinase (FAK), Src and paxillin were also phosphorylated. Treatment with FAK inhibitor resulted in robust suppression of FAK-Y397 and Src-Y416 phosphorylation stimulated by sulfatide, but not suppression of integrin β3 phosphorylation. Src inhibitors repressed Src-Y416 and FAK Y861 and Y925 phosphorylation, but not FAK-Y397 and integrin β3 phosphorylation. After mutation of integrin β3 (Y773F and Y785F), FAK or Src phosphorylation failed to be stimulated by sulfatide. Moreover, β3 Y773 and Y785 phosphorylation was suppressed by insulin-like growth factor receptor knockdown even in cells stimulated by sulfatide. In assays of immunoprecipitation and immunostaining with integrin αV or β3 antibody, labeled sulfatide was found in the complex and co-localized with integrin αVβ3. Taken together, this study demonstrated that elevated sulfatide bound to integrin αVβ3 and induced clustering and phosphorylation of αVβ3 instead of matrix ligand binding, triggering outside-in signaling.

RUNX3 regulates renal cell carcinoma metastasis via targeting miR-6780a-5p/E-cadherin/EMT signaling axis

Runt-related transcription factor 3 (RUNX3) is a tumor suppressor in many human solid tumors. In this study, renal cell carcinoma (RCC) microarray analysis showed that the level of RUNX3 expression was lower in RCC tissue than in adjacent normal renal tissues, and was correlated with depth of invasion (pT stage) (P<0.001) and Tumor Node Metastasis (TNM) stage (P<0.001). RUNX3 expression was negatively correlated with poor 5-year overall and disease-free patient survival. RUNX3 suppressed RCC metastasis and invasion and increased levels of E-cadherin, an important marker of epithelial-mesenchymal transition, in vitro and in vivo. RUNX3 also inhibited microRNA-6780a-5p, which directly targeted the E-cadherin 3'untranslated region and decreased its expression. We confirmed that miR-6780a-5p mimics abrogated RUNX3-mediated E-cadherin upregulation and RCC metastasis/invasion inhibition. Thus, RUNX3 targeted the miR-6780a-5p/E-cadherin/EMT signaling axis to suppress renal carcinoma cell migration and invasion. This pathway illustrates a new RUNX3 function and provides potential targets for the treatment of RUNX3 mutant and loss-of-function RCC tumors. RUNX3 may also act as an effective prognostic indicator in RCC.

RUNX3 regulates hepatocellular carcinoma cell metastasis via targeting miR-186/E-cadherin/EMT pathway

Runt-related transcription factor 3 (RUNX3) has been reported as a tumor suppressor in some kinds of cancers. In the present study, hepatocellular carcinoma (HCC) microarray analysis showed that RUNX3 expression was significantly lower in HCC tissues compared with that in adjacent non-tumor tissues, and was negatively associated with metastasis and TNM stage. RUNX3 was an independently prognostic factor for 5-year overall and disease-free patient survival. Mechanically, RUNX3 repressed metastasis and invasion of HCC, and increased E-cadherin expression. RUNX3 also repressed microRNA-186 to increase E-cadherin expression. We demonstrated that miR-186 mimics attenuated RUNX3-induced increase of E-cadherin and inhibition of metastasis and invasion. In conclusion, RUNX3 suppressed HCC cell migration and invasion by targeting the miR-186/E-cadherin/EMT pathway. RUNX3 may be recommended as an effective prognostic indicator and therapeutic target for patients with HCC.

miR-218 suppresses gastric cancer cell proliferation and invasion via regulation of angiopoietin-2

Novel targeted therapies need to be developed for gastric cancer, the third most common cancer type and the second most common cause of cancer-related mortality in China. Previous studies indicate that angiopoietin (Ang)-2 serves a role in the proliferation, migration, invasion and adhesion of malignant cells. The present study identified, using functional studies, that exogenous expression of miR-218 increased migration of NCI-87 and HGC-27 gastric cancer cells, which coincided with a reduction in the expression of Ang-2. In addition, intratumoral delivery of miR-218 inhibited proliferation and angiogenesis of gastric cancer cells in vivo, with a corresponding decreased in Ang-2 expression. These results indicate that miR-218 serves an important role in gastric cancer tumorigenesis through regulating the expression of Ang-2. Therefore, components of miR-218/Ang-2 signaling could provide novel therapeutic targets for the treatment of gastric cancer.

PinX1 serves as a potential prognostic indicator for clear cell renal cell carcinoma and inhibits its invasion and metastasis by suppressing MMP-2 via NF-κB-dependent transcription

PIN2/TRF1-interacting telomerase inhibitor 1 (PinX1) is a novel cloned gene which has been identified as a major haploinsufficient tumor suppressor essential for maintaining telomerase activity, the length of telomerase and chromosome stability. This study explored the clinical significance and biological function of PinX1 in human clear cell renal cell carcinoma (ccRCC). The clinical relevance of PinX1 in ccRCC was evaluated using tissue microarray and immunohistochemical staining in two independent human ccRCC cohorts. Our data demonstrated that PinX1 expression was dramatically decreased in ccRCC tissues compared with normal renal tissues and paired adjacent non-tumor tissues. Low PinX1 expression was significantly correlated with depth of invasion, lymph node metastasis and advanced TNM stage in patients, as well as with worse overall and disease-specific survival. Cox regression analysis revealed that PinX1 expression was an independent prognostic factor for ccRCC patients. Moreover, PinX1 inhibited the migration and invasion of ccRCC by suppressing MMP-2 expression and activity via NF-κB-dependent transcription in vitro. In vivo studies confirmed that PinX1 negatively regulated ccRCC metastasis and the expression of MMP-2 and NF-κB-p65. These findings indicate that PinX1 suppresses ccRCC metastasis and may serve as a ccRCC candidate clinical prognostic marker and a potential therapeutic target.

SOX2 inhibits metastasis in gastric cancer

PURPOSE

To investigate the potential role of SOX2 in gastric cancer (GC) metastasis.

METHODS

The SOX2 expression was detected using immunohistochemistry on a GC tissue microarray. The correlations of SOX2 expression with clinicopathological factors and 5-year survival were evaluated. To test the role of SOX2 in inhibiting GC metastasis, the cell transwell assay was performed. Real-time PCR and Western blot were used to explore the possible mechanism that SOX2 inhibits GC metastasis.

RESULTS

In the present study, SOX2 expression was downregulated in GC tissues when compared to matching normal tissues. Moreover, patients with high SOX2 expression in cancerous tissues had less lymph node metastasis and better treatment outcome. At the subcellular level, SOX2 inhibited the GC cell migration and invasion by upregulating p21 expression. Moreover, SOX2 was determined to associate with the nuclear p21 expression. GC patients with high SOX2 and nuclear p21 expression had synergistically less lymph node metastasis and the better overall survival.

CONCLUSION

Our results suggest that SOX2 is a promising and favorable metastatic biomarker for GC.

Novel endogenous angiogenesis inhibitors and their therapeutic potential

Angiogenesis, the formation of new blood vessels from the pre-existing vasculature is essential for embryonic development and tissue homeostasis. It also plays critical roles in diseases such as cancer and retinopathy. A delicate balance between pro- and anti-angiogenic factors ensures normal physiological homeostasis. Endogenous angiogenesis inhibitors are proteins or protein fragments that are formed in the body and have the ability to limit angiogenesis. Many endogenous angiogenesis inhibitors have been discovered, and the list continues to grow. Endogenous protein/peptide inhibitors are relatively less toxic, better tolerated and have a lower risk of drug resistance, which makes them attractive as drug candidates. In this review, we highlight ten novel endogenous protein angiogenesis inhibitors discovered within the last five years, including ISM1, FKBPL, CHIP, ARHGAP18, MMRN2, SOCS3, TAp73, ZNF24, GPR56 and JWA. Although some of these proteins have been well characterized for other biological functions, we focus on their new and specific roles in angiogenesis inhibition and discuss their potential for therapeutic application.

Implication of α2β1 integrin in anoikis of MCF-7 human breast carcinoma cells

Silencing of α2β1 integrin expression significantly promoted anchorage-dependent apoptosis (anoikis) and drastically reduced clonal activity of MCF-7 human breast carcinoma cells. Depletion of α2β1 enhanced the production of apoptotic protein p53 and of inhibitor of cyclin-dependent protein kinases, p27, while downregulating antiapoptotic protein Bcl-2 and multifunctional protein cMyc. Blocking the expression of α2β1 had no effect on activity of protein kinase Akt, but it sharply increased the kinase activity of Erk1/2. Pharmacological inhibition of Erk1/2 had a minor effect on anoikis of control cells, while it reduced anoikis of cells with downregulated α2β1 to the level of control cells. The data show for the first time that integrin α2β1 is implicated in the protection of tumor cells from anoikis through a mechanism based on the inhibition of protein kinase Erk.

Decreased expression of CHIP leads to increased angiogenesis via VEGF-VEGFR2 pathway and poor prognosis in human renal cell carcinoma

CHIP (c-terminal Hsp70-interacting protein) is an E3 ligase which may play different roles in different cancers. The elucidation of the VHL-HIF-1α (hypoxia inducible factor-1α)-VEGF (vascular endothelial growth factor) pathway has led to the development of targeted therapy in renal cell carcinoma (RCC). However, little is known about the role of CHIP and the relationship between CHIP and VEGF-VEGFR2 (VEGF receptor 2) pathway in RCC. In this study, we found that the expression of CHIP was downregulated and significantly correlated with pT status (P = 0.022) and TNM stage (P = 0.022) in 304 RCC and 35 normal renal tissues using tissue microarray. Moreover, low expression of CHIP is a strong and independent negative prognostic value for RCC. In vitro, CHIP negatively regulated RCC cell migration, invasion and angiogenesis. In addition, ELISA tests showed that restoration of CHIP inhibited, while knockdown promoted, the secreted level of VEGF. Furthermore, western blot indicated that the VEGFR2 protein level was reduced after CHIP overexpression. Our findings demonstrate for the first time that CHIP may be involved in RCC angiogenesis through regulating VEGF secretion and expression of VEGFR2. CHIP may serve as promising prognostic biomarker of angiogenesis and may constitute a potential therapeutic target in RCC.

Antitumor and antimetastatic effects of pemetrexed-loaded targeted nanoparticles in B16 bearing mice

Using nanoparticle delivery for anticancer therapy is a potential new drug modality. We developed a novel gelatinase-stimuli nanoparticle. In this study, we studied the antitumor and antimetastasis effect of pemetrexed-loaded targeted nanoparticles and evaluated the correlation between E-cadherin expression and lung metastasis in subcutaneous xenograft model. Compared with free pemetrexed, pemetrexed-loaded targeted nanoparticles exhibited the best antitumor and antimetastasis efficacy among the four therapeutic groups. The study also indicated that there was an inverse correlation between lung metastasis and E-cadherin expression. These results showed pemetrexed-loaded targeted nanoparticles may be a potent drug for tumor therapy and our preclinical data could provide new direction for clinical therapy of malignant melanoma.

Effects of JWA, XRCC1 and BRCA1 mRNA expression on molecular staging for personalized therapy in patients with advanced esophageal squamous cell carcinoma

BACKGROUND

DNA damage repair genes JWA, XRCC1 and BRCA1 were associated with clinical outcomes and could convert the response to the cisplatin-based therapy in some carcinomas. The synergistic effects of JWA, XRCC1 and BRCA1 mRNA expression on personalized therapy remain unknown in advanced esophageal squamous cell carcinoma (ESCC).

METHODS

We employed quantitative real-time polymerase chain reaction (qPCR) to determine the expression of JWA, XRCC1 and BRCA1 mRNA in paraffin-embedded specimen from 172 patients with advanced ESCC who underwent the first-line cisplatin-or docetaxel-based treatments.

RESULTS

High JWA or XRCC1mRNA expression was correlated with longer median overall survival (mOS) in all the patients (both P<0.001) or in subgroups with different regimens (all P<0.05), but not correlated with response rate (RR, all P>0.05). Multivariate analysis revealed that high JWA (HR 0.22; 95% CI 0.13-0.37; P<0.001) or XRCC1 (HR 0.36; 95% CI 0.21-0.63; P<0.001) mRNA expression emerged as the independent prognostic factors for ESCC patients in this cohort. But no significant difference in prognostic efficacy was found between JWA plus XRCC1 and JWA alone through ROC analysis. Further subgroup analysis showed cisplatin-based treatments could improve mOS of patients with low JWA expression (P<0.05), especially in those with low BRCA1 expression simultaneously (P<0.001); while in patients with high JWA expression, high BRCA1 mRNA expression was correlated with increased mOS in docetaxel-based treatments (P=0.044).

CONCLUSION

JWA, XRCC1and BRCA1 mRNA expression could be used as predictive markers in molecular staging for personalized therapy in patients with advanced ESCC who received first-line cisplatin- or docetaxel-based treatments.

PinX1 inhibits the invasion and metastasis of human breast cancer via suppressing NF-κB/MMP-9 signaling pathway

Background

PinX1 (PIN2/TRF1-interacting telomerase inhibitor 1) was suggested to be correlated with tumor progression. This study was designed to evaluate the role of PinX1 in human breast cancer.

Methods

To evaluate the function of PinX1 in breast cancer, we used a tissue microarray (TMA) of 405 human breast cancer patients and immunohistochemistry to analyze the correlation between PinX1 expression and clinicopathologic variables and patient survival. We also detected the abilities of cell migration and invasion in breast cancer by performing cell migration and invasion assay, gelatin zymography and western blot analysis. Lastly, we set up the nude mice model by Tail vein assay to exam the functional role of PinX1 in breast cancer metastasis.

Results

We found that low PinX1 expression was associated with lymph node metastasis (P = 0.002) and histology grade (P = 0.001) in patients, as well as with poorer overall and disease-specific survival (P = 0.010 and P = 0.003, respectively). Moreover, we identified that PinX1 inhibited the migration and invasion of breast cancer by suppressing MMP-9 expression and activity via NF-κB-dependent transcription in vitro. Finally, our mice model confirmed that PinX1 suppressed breast cancer metastasis in vivo.

Conclusions

Our data revealed that low PinX1 expression was an independent negative prognostic factor for breast cancer patients. These findings suggested that PinX1 might be function as a tumor metastasis suppressor in the development and progression of breast cancer by regulating the NF-κB/MMP-9 signaling pathway, and might be a prognostic marker as well as a therapeutic target for breast cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0332-2) contains supplementary material, which is available to authorized users.

PinX1 inhibits cell proliferation, migration and invasion in glioma cells

PinX1 induces apoptosis and suppresses cell proliferation in some cancer cells, and the expression of PinX1 is frequently decreased in some cancer and negatively associated with metastasis and prognosis. However, the precise roles of PinX1 in gliomas have not been studied. In this study, we found that PinX1 obviously reduced the gliomas cell proliferation through regulating the expressions of cell cycle-relative molecules to arrest cell at G1 phase and down-regulating the expression of component telomerase reverse transcriptase (hTERT in human), which is the hardcore of telomerase. Moreover, PinX1 could suppress the abilities of gliomas cell wound healing, migration and invasion via suppressing MMP-2 expression and increasing TIMP-2 expression. In conclusion, our results suggested that PinX1 may be a potential suppressive gene in the progression of gliomas.

Cullin1 is a novel prognostic marker and regulates the cell proliferation and metastasis in colorectal cancer

PURPOSE

To investigate the precise function of Cullin1 (CUL1) in colorectal cancer (CRC).

METHODS

Immunohistochemistry was performed to test the expression of CUL1 on a CRC tissue microarray containing the tumor and corresponding normal tissues. Simultaneously, the correlation of CUL1 expression with clinicopathological parameters and survival was evaluated. CUL1 was over-expressed or knocked down in HCT116 and SW480 cells, then the cell proliferation, migration and invasion assays in vitro and in vivo were performed.

RESULTS

In this study, we found that CUL1 expression was significantly up-regulated in CRC compared with normal colon tissues. High CUL1 expression was positively associated with lymph node metastasis (P = 0.007) and tumor diameter (P = 0.052). Multivariate Cox regression analysis revealed that high CUL1 expression was an independent unfavorable prognostic factor for CRC patients (HR = 13.9, 95% confidence interval = 5.89-32.6, P < 0.001). Moreover, we found that CUL1 over-expression induced CRC cell proliferation and the growth of xenografts in nude mice via the changing of cell-cycle proteins. In addition, increased CUL1 expression in CRC cells significantly promoted cell migration and invasion abilities in vitro and peritoneal metastasis in vivo through inducing high expression of MMPs.

CONCLUSION

Our findings imply that CUL1 may serve as promising prognostic markers in CRC patients.

Effects of the JWA gene in the regulation of human breast cancer cells

The present study aimed to investigate whether the JWA gene can regulate the proliferation, migration and invasion of human breast cancer cells through the MAPK signaling pathway. The role of JWA in proliferation, migration, invasion and apoptosis was investigated in the MDA‑MB‑231 human breast cancer cell line. Following transfection with JWA‑small interfering (si)RNA, the effect of JWA on apoptosis was assessed by Western blot analysis, proliferation was determined using Transwell chambers and cell migration and invasion were analyzed by transwell assay. The expression levels of extracellular signal‑regulated kinase (ERK) 1/2, CSBP/RK/Mpk2 kinase (p38) and c‑Jun N‑terminal kinase (JNK) were detected using Western blot analysis in the siRNA and control groups. The expression of JWA in the breast cancer cells was significantly lower compared with the normal breast cells. Downregulation of JWA protein levels reduced the apoptosis and enhanced proliferation, migration and invasion of the MDA‑MB‑231 cells in vitro. The results of the Western blot analysis demonstrated that, compared with the control groups, the expression levels of phosphorylated (p‑)p38 decreased significantly in the JWA siRNA group. No significant changes were observed in the expression levels of p‑ERK1/2 or p‑JNK. Therefore, the JWA gene may regulate human breast cancer cells through the MAPK signaling pathway using different types of regulation.

JWA reverses cisplatin resistance via the CK2-XRCC1 pathway in human gastric cancer cells

Gastric cancer is the third most common malignancy in China, with a median 5-year survival of only 20%. Cisplatin has been used in first-line cancer treatment for several types of cancer including gastric cancer. However, patients are often primary resistant or develop acquired resistance resulting in relapse of the cancer and reduced survival. Recently, we demonstrated that the reduced expression of base excision repair protein XRCC1 and its upstream regulator JWA in gastric cancerous tissues correlated with a significant survival benefit of adjuvant first-line platinum-based chemotherapy as well as XRCC1 playing an important role in the DNA repair of cisplatin-resistant gastric cancer cells. In the present study, we demonstrated the role of JWA in cisplatin-induced DNA lesions and aquired cisplatin resistance in five cell-culture models: gastric epithelial cells GES-1, cisplatin-sensitive gastric cancer cell lines BGC823 and SGC7901, and the cisplatin-resistant gastric cancer cell lines BGC823/DDP and SGC7901/DDP. Our results indicated that JWA is required for DNA repair following cisplatin-induced double-strand breaks (DSBs) via XRCC1 in normal gastric epithelial cells. However, in gastric cancer cells, JWA enhanced cisplatin-induced cell death through regulation of DNA damage-induced apoptosis. The protein expression of JWA was significantly decreased in cisplatin-resistant cells and contributed to cisplatin resistance. Interestingly, as JWA upregulated XRCC1 expression in normal cells, JWA downregulated XRCC1 expression through promoting the degradation of XRCC1 in cisplatin-resistant gastric cancer cells. Furthermore, the negative regulation of JWA to XRCC1 was blocked due to the mutation of 518S/519T/523T residues of XRCC1, and indicating that the CK2 activated 518S/519T/523T phosphorylation is a key point in the regulation of JWA to XRCC1. In conclusion, we report for the first time that JWA regulated cisplatin-induced DNA damage and apoptosis through the CK2—P-XRCC1—XRCC1 pathway, indicating a putative drug target for reversing cisplatin resistance in gastric cancer.

Lack of JWA Enhances Neurogenesis and Long-Term Potentiation in Hippocampal Dentate Gyrus Leading to Spatial Cognitive Potentiation

JWA (Arl6ip5), a homologous gene of glutamate-transporter-associated protein 3-18 (GTRAP3-18) and addicsin, is highly expressed in hippocampus. We generated systemic and neuronal JWA knockout (JWA-KO and JWA-nKO) mice to investigate the influence of JWA deficiency on spatial cognitive performance, process of neurogenesis, and induction of long-term potentiation (LTP) in hippocampal dentate gyrus (DG). In comparison with wild-type (WT) mice and JWA (loxP/loxP) (control of JWA-nKO) mice, 8-week-old JWA-KO mice and JWA-nKO mice showed spatial cognitive potentiation as assessed by Morris water maze test. In hippocampal DG of JWA-nKO mice, either survival and migration or neurite growth of newborn neurons were significantly enhanced without the changes in proliferation and differentiation of stem cells. In addition, the increase of LTP amplitude and the decline of LTP threshold were observed in DG, but not in CA1 region, of JWA-nKO mice compared to control mice. The levels of hippocampal FAK, Akt, and mTOR phosphorylation in JWA-nKO mice were higher than those in control mice. The PI3K or FAK inhibitor could abolish the enhanced neurogenesis and LTP induction in JWA-nKO mice, which was accompanied by disappearance of the spatial cognitive potentiation. The treatment of JWA-nKO mice with 3'-azido-3'-deoxythymidine (AZT), a telomerase inhibitor, suppressed not only the enhanced neurogenesis but also the enhanced LTP induction in DG, but it did not affect the LTP induction in CA1 region. The results suggest that the JWA deficiency through cascading FAK-PI3K-Akt-mTOR pathway increases the newborn neurons and enhances the LTP induction in hippocampal DG, which leads to the spatial cognitive potentiation.

JWA regulates human esophageal squamous cell carcinoma and human esophageal cells through different mitogen-activated protein kinase signaling pathways

The aim of the present study was to investigate whether the JWA gene regulates the proliferation, migration and invasion of human esophageal squamous cell carcinoma (ESCC) and normal human esophageal cell lines through mitogen-activated protein kinase (MAPK) signal transduction pathways. The role of JWA in proliferation, migration, invasion and apoptosis was investigated in the Eca109 human ESCC and HET-1A normal human esophageal cell lines via transfection with JWA-small interfering (si)RNA. Western blot analysis was conducted to observe the effect of JWA on apoptosis and the regulatory effect of JWA on proliferation was determined using a thiazolyl blue tetrazolium bromide (MTT) assay. Cellular migration and invasion were analyzed via a Transwell assay. In addition, the expression levels of extracellular signal-regulated protein kinases 1 and 2 (ERK1/2), c-Jun N-terminal kinase (JNK) and p38 MAPK following JWA-siRNA transfection were detected by western blot analysis and compared with those of untreated cells. The downregulation of JWA protein decreased apoptosis and increased the proliferation, migration and invasion of the Eca109 and HET-1A cell lines. In the Eca109 cell line, the expression levels of phosphorylated (p)-ERK1/2 and p-JNK, but not those of p-p38, decreased significantly in the JWA siRNA group compared with those in the control groups. However, in the HET-1A cell line, JWA-siRNA transfection significantly inhibited the expression of p-p38 and demonstrated no effect on the expression levels of p-ERK1/2 and p-JNK. In conclusion, the JWA gene may regulate the ESCC and human esophageal cell lines through MAPK signaling pathways via different regulatory mechanisms.

Astrocytic JWA expression is essential to dopaminergic neuron survival in the pathogenesis of Parkinson's disease

AIMS

To investigate the role of astrocytic JWA expression in dopaminergic (DA) neuron degeneration and in the pathogenesis of Parkinson's disease (PD).

METHODS

Conditional astrocytic JWA null (JWA∆2/∆2/GFAP-Cre) mice and U251 glioma cells were used to evaluate the effects of JWA gene on DA neuron degeneration. The oxidative stress-driven molecular events were determined in both in vivo and in vitro models.

RESULTS

Conditional astrocytic JWA knockout resulted in significant activation of astrocytes measured by increase in glial fibrillary acidic protein-positive cells (1.34×10(3)±74.5 vs. 8.44×10(3)±1.35×10(3), P<0.01) in mouse substantia nigra, accompanied by loss of DA neurons (1.03×10(4)±238 vs. 6.17×10(3)±392, P<0.001). Deficiency of JWA significantly aggravated reactive oxygen species (ROS) accumulation in substantia nigra compared with the wild-type mice. Increasing JWA expression in U251 glioma cells inhibited ROS with a concomitant increase in intracellular glutathione. Furthermore, suppression of IKKβ-nuclear factor (NF)-κB signaling pathway was shown to regulate JWA in a PD model.

CONCLUSIONS

The JWA gene exerts neuroprotective roles against DA neuronal degeneration via modulating intracellular redox status and NF-κB signaling pathway and is a potential treatment target for PD.

ING4 regulates JWA in angiogenesis and their prognostic value in melanoma patients

Background:

We previously showed that inhibitor of growth family member 4 (ING4) inhibits melanoma angiogenesis, and JWA suppresses the metastasis of melanoma cells. As angiogenesis is essential for tumour metastasis, further investigation of the function of ING4 and JWA in melanoma angiogenesis is needed, and their prognostic value are of great interest.

Methods:

Western blot, tube-formation assays and luciferase assays were used to investigate the correlation between ING4 and JWA in melanoma angiogenesis. JWA and integrin-linked kinase (ILK) expression was determined on a tissue microarray constructed from 175 biopsies.

Results:

ING4 promoted JWA expression by activating JWA promoter. Furthermore, the regulation of growth and tube formation of endothelial cells by ING4 was partially JWA dependent. Also, ING4 inhibited the ILK-induced angiogenesis signalling pathway via JWA. Moreover, reduced JWA, or increased ILK, expression was closely associated with 5-year disease-specific survival of melanoma patients (P=0.001 and 0.007, respectively). There was also a positive correlation between ING4 and JWA yet a negative correlation between ING4 and ILK. Importantly, their concomitant expressions were significantly related to 5-year survival of melanoma patients (P=0.002 and 0.003, respectively).

Conclusion:

JWA has an important role in ING4-regulated melanoma angiogenesis, and ING4/JWA/ILK are promising prognostic markers and may be used as anti-angiogenic therapeutic targets for melanoma.

JWA suppresses tumor angiogenesis via Sp1-activated matrix metalloproteinase-2 and its prognostic significance in human gastric cancer

JWA, a multifunctional microtubule-binding protein, plays an important role in regulating tumor metastasis via inhibition of matrix metalloproteinase-2 (MMP-2). Recent investigations suggest that MMP-2 is an angiogenesis-associated molecule. In this study, we provide novel evidence that JWA inhibits tumor angiogenesis in gastric cancer (GC). In two independent retrospective GC cohorts, we found that the expression of JWA was downregulated and that of MMP-2 was upregulated in GC tissues compared with the same in normal gastric mucosa. For patients treated with surgery alone, a strong and independent negative prognostic value was shown for low JWA and high MMP-2 expressions separately, which was even stronger when combined (hazard ratio = 7.75, P < 0.001, in the training cohort; hazard ratio = 2.31, P < 0.001, in the validation cohort). Moreover, we found that loss of JWA expression was strongly correlated with increased GC angiogenesis. In vitro, JWA inhibited MMP-2 at both messenger RNA and protein levels by modulating Sp1 activity. Knockdown of endogenous JWA resulted in enhanced human umbilical vein endothelial cell tube formation and MMP-2 expression. Furthermore, JWA was found to inhibit Sp1 activity via an ubiquitin-proteasome-dependent mechanism and to downregulate the expression of the proangiogenic MMP-2. Our findings imply that JWA and MMP-2 may serve as promising prognostic markers in resectable GC, with JWA as a useful biomarker of angiogenesis in GC and a potential therapeutic target by MMP-2 modulation.

JWA inhibits melanoma angiogenesis by suppressing ILK signaling and is an independent prognostic biomarker for melanoma

Melanoma is the deadliest cutaneous malignancy because of its high incidence of metastasis. Melanoma growth and metastasis relies on sustained angiogenesis; therefore, inhibiting angiogenesis is a promising approach to treat metastatic melanoma. JWA is a novel microtubule-associated protein and our previous work revealed that JWA inhibited melanoma cell invasion and metastasis. However, the role of JWA in melanoma angiogenesis and the prognostic value are still unknown. Here, we report that JWA in melanoma cells significantly inhibited the tube formation of endothelial cells. In addition, JWA regulated integrin-linked kinase (ILK) through integrin αVβ3 and such regulation was achieved through the transcription factor Sp1. Notably, both in vitro and in vivo angiogenesis assays revealed that JWA dramatically suppressed melanoma angiogenesis by inhibiting ILK signaling. Furthermore, we examined the expression of JWA protein in a large set of melanocytic lesions (n = 505) at different stages by tissue microarray and found an inverse correlation between JWA expression and melanoma progression (P = 5 × 10(-6)). Importantly, reduced JWA expression was correlated with a poorer overall, and disease-specific 5 year survival of patients (P = 0.001 and 0.007, respectively). Multivariate Cox regression analyses indicated that JWA was an independent prognostic marker for melanoma patients. Moreover, we found a significant negative correlation between JWA and ILK in melanoma biopsies, and their concomitant expression was closely correlated with melanoma patient survival (P = 0.004), further indicating the regulation of ILK expression by JWA is critical in melanoma. Taken together, our data highlight the function of JWA in melanoma angiogenesis and reveal the clinical prognostic value of JWA.

High FAK combined with low JWA expression: clinical prognostic and predictive role for adjuvant fluorouracil-leucovorin-oxaliplatin treatment in resectable gastric cancer patients

BACKGROUND

The multifunctional protein JWA was previously identified as a novel regulator of focal adhesion kinase (FAK/PTK2) in suppressing cancer cell adhesion, invasion and metastasis. JWA is downregulated in gastric cancer (GC) and a prognostic and predictive biomarker for resectable GC. However, the value of FAK combined with JWA for GC patients as a biomarker has not been studied. Here we evaluated the roles of FAK alone and combined with JWA in GC patients treated with surgery alone or combined with adjuvant platinum-based chemotherapy.

METHODS

Two tissue microarrays were constructed of specimens from resected GC (n = 709 in total) for detection of FAK and JWA expression by immunohistochemistry. Correlations between both proteins and clinicopathological features as well as prognostic and predictive values were evaluated.

RESULTS

Compared with adjacent non-cancerous tissues, FAK protein levels were remarkably up-regulated in GC lesions (P < 0.001). High FAK alone or combined with low JWA expression significantly correlated with worse overall survival (OS) (both P < 0.001 in two cohorts). Simultaneously, JWA plus FAK expression was a more valuable prognostic biomarker than JWA or FAK alone. Moreover, the patients with high FAK only or combined with low JWA had significant benefit from adjuvant fluorouracil-leucovorin-oxaliplatin (FLO) therapy compared with those with surgery alone (P = 0.003); however, the cases with adjuvant fluorouracil-leucovorin-cisplatin (FLP) therapy did not show these effects.

CONCLUSION

FAK plus JWA may serve as a more prognostic and predictive biomarker for GC than each separately with a potential clinical application.

Survivin promotion of melanoma metastasis requires upregulation of α5 integrin

Survivin is an apoptotic and mitotic regulator that is overexpressed in melanoma and a poor prognostic marker in patients with metastatic disease. We recently showed that Survivin enhances melanoma cell motility through Akt-dependent upregulation of α5 integrin. However, the functional role of Survivin in melanoma metastasis is not clearly understood. We found that overexpression of Survivin in LOX and YUSAC2 human melanoma cells increased colony formation in soft agar, and this effect was abrogated by knockdown of α5 integrin by RNA interference. We employed melanoma cell xenografts to determine the in vivo effect of Survivin overexpression on melanoma metastasis. Although Survivin overexpression did not affect primary tumor growth of YUSAC2 or LOX subcutaneous tumors, or indices of proliferation or apoptosis, it significantly increased expression of α5 integrin in the primary tumors and formation of metastatic colonies in the lungs. Additionally, Survivin overexpression resulted in enhanced lung colony formation following intravenous (i.v.) injection of tumor cells in vivo and increased adherence to fibronectin-coated plastic in vitro. Importantly, in vivo inhibition of α5 integrin via intraperitoneal injection of an α5β1 integrin-blocking antibody significantly slowed tumor growth and reduced Survivin-enhanced pulmonary metastasis. Knockdown of α5 integrin in cells prior to i.v. injection also blocked Survivin-enhanced lung colony formation. These findings support a direct role for Survivin in melanoma metastasis, which requires α5 integrin and suggest that inhibitors of α5 integrin may be useful in combating this process.

MDM2 is a useful prognostic biomarker for resectable gastric cancer

Expression of MDM2 protein appears to be increased in malignancy and correlated to prognosis of tumors, but its role in gastric cancer remains controversial. Our recent investigations indicated that JWA was a novel candidate biomarker for gastric cancer. To evaluate the impact of MDM2 protein expression alone, and in combination with JWA, on the prognostic and predictive of patients with resectable gastric cancer, expression of MDM2 and JWA were examined by immunohistochemistry in three large cohorts (total n = 1131) of patient with gastric cancer. We found that MDM2 protein levels were significantly upregulated in gastric cancer (70.4%, 57 of 81) compared with adjacent non-cancerous tissues. High tumoral MDM2 expression significantly correlated with clinicopathologic characteristics, as well as with shorter overall survival (OS; P < 0.001 for all cohorts) in patients without adjuvant treatment. The effect of adjuvant fluorouracil-leucovorin-oxaliplatin (FLO) in improving OS compared with surgery alone was evident only in the high MDM2 group (hazard ratio = 0.57; 95% confidence interval, 0.37-0.89; P = 0.013). Furthermore, knockdown of MDM2 and overexpression of JWA had a synergistic effect on suppression of gastric cancer cell proliferation and migration. Patients with low MDM2 and high JWA expression had a better outcome of survival compared with the other groups (P < 0.001 for all cohorts). For the first time, our data suggest that MDM2 is a potent prognostic and predictive factor for benefit from adjuvant fluorouracil-leucovorin-oxaliplatin chemotherapy in resectable gastric cancer. The combination of MDM2 expression and JWA could serve as a more effective candidate prognostic biomarker for gastric cancer.

PRAF2 stimulates cell proliferation and migration and predicts poor prognosis in neuroblastoma

Prenylated Rab acceptor 1 domain family, member 2 (PRAF2) is a novel 19-kDa protein with four transmembrane-spanning domains that belongs to the PRAF protein family. Neuroblastoma (NB) is the most common malignant extracranial solid tumor of childhood that originates in primitive cells of the developing sympathetic nervous system. We investigated the correlation of PRAF2 mRNA expression to NB clinical and genetic parameters using Affymetrix expression analysis of a series of 88 NB tumors and examined the functional role of PRAF2 in an NB cell line using RNA interference. We found that high PRAF2 expression is significantly correlated to several unfavorable NB characteristics: MYCN amplification, high age at diagnosis, poor outcome and high INSS stage. The shRNA-mediated PRAF2 downregulation in the SK-N-SH NB cell line resulted in decreased cellular proliferation, migration and matrix-attachment. These findings were confirmed in NB patient tumor samples, where high PRAF2 expression is significantly correlated to bone and bone marrow metastasis, the main cause of death in NB patients. The present study shows that PRAF2 plays an essential role in NB tumorigenesis and metastasis.

Synergistic role between p53 and JWA: prognostic and predictive biomarkers in gastric cancer

Expression of p53 appears to be correlated to prognosis in patients with malignancy, but its role in gastric carcinoma has remained controversial. Recently we reported that JWA, an ADP-ribosylation-like factor 6 interacting protein 5 (ARL6ip5), was both prognostic for overall survival and predictive for platinum-based treatment of gastric cancer. In this study, we aimed to investigate p53 expression as a prognostic and predictive marker in resectable gastric cancer, alone and in combination with JWA. Expression of p53 was examined in three large patient cohorts (total n = 1155) of gastric cancer. High expression of p53 was significantly correlated with unfavorable clinicopathologic parameters and decreased overall patient survival. Furthermore, patients with high p53 expression in tumors acquired remarkable survival benefit from adjuvant first-line platinum-based-chemotherapy. The synergy between p53 and JWA in predicting patient outcome was demonstrated, while no significantly elevated predictive value concerning chemotherapy was observed. Thus, p53 expression is a potent prognostic and predictive factor for resectable gastric cancer with adjuvant platinum-based chemotherapy. A combined effect of p53 with JWA as efficient prognostic indicators was found for the first time.