HAX1 Augments Cell Proliferation, Migration, Adhesion, and Invasion Induced by Urokinase-Type Plasminogen Activator Receptor

HAX1 impact on collective cell migration, cell adhesion, and cell shape is linked to the regulation of actomyosin contractility

HAX1 protein is involved in the regulation of apoptosis, cell motility and calcium homeostasis. Its overexpression was reported in several tumors, including breast cancer. This study demonstrates that HAX1 has an impact on collective, but not single-cell migration, thus indicating the importance of cell–cell contacts for the HAX1-mediated effect. Accordingly, it was shown that HAX1 knockdown affects cell–cell junctions, substrate adhesion, and epithelial cell layer integrity. As demonstrated here, these effects can be attributed to the modulation of actomyosin contractility through changes in RhoA and septin signaling. Additionally, it was shown that HAX1 does not influence invasive potential in the breast cancer cell line, suggesting that its role in breast cancer progression may be linked instead to collective invasion of the epithelial cells but not single-cell dissemination.

HAX-1 promotes the migration and invasion of hepatocellular carcinoma cells through the induction of epithelial-mesenchymal transition via the NF-κB pathway

The expression of HS-1-associated protein X-1 (HAX-1) plays a major role in the development of hepatocellular carcinoma (HCC). However, the function of HAX-1 in HCC metastasis is unclear. Quantitative real-time PCR and western blotting were used to examine HAX-1 expression in HCC cell lines with different metastatic potential, and in tumor tissues with or without intrahepatic metastasis. HCC tissue arrays (n = 144) were used to assess correlations between clinicopathological parameters and HAX-1 expression. We also examined the effect of HAX-1 on promoting HCC cell metastasis in vivo and in vitro. The results showed that the expression levels of HAX-1 were higher in metastatic HCC cell lines than in non-metastatic HCC cell lines. HAX-1 was also significantly upregulated in primary HCC tissues with intrahepatic metastasis compared with those without intrahepatic metastasis. HCC in patients with high HAX-1 expression is more likely to metastasize. HAX-1 expression was associated with malignant progression and poor prognosis, and HAX1 silencing inhibited HCC cell migration and invasion in vitro and decreased HCC cell lung metastasis in vivo, whereas HAX-1 overexpression had the inverse effect. Moreover, HAX-1 increased HCC cell metastasis by promoting the epithelial-mesenchymal transition (EMT) process. Finally, we revealed that HAX-1 modulated EMT in HCC cells by increasing NF-κB/p65 nuclear translocation. In conclusion, HAX-1 promotes HCC metastasis by EMT through activating the NF-κB pathway, suggesting that HAX-1 could be a potential therapeutic target for HCC treatment.

Prognostic value of urokinase plasminogen activator system in non-small cell lung cancer: A systematic review and meta-analysis

Current relevant research suggests there are significant differences between the expression of the urokinase plasminogen activator (uPA) system in cancer tissues and in normal tissues. However, the potential effectiveness of the uPA system as a prognostic biomarker of non-small cell lung cancer (NSCLC) remains unclear. In the present study, a systematic review and meta-analysis were performed to evaluate the relevance of the uPA system in the prognosis of patients with NSCLC. Using the PubMed, EMBASE, Web of Science and Cochrane Library databases, data from relevant academic journal articles were extracted and subjected to analysis. Associations between expression profiles pertaining to the uPA system and the overall survival (OS) of patients with NSCLC were analyzed. The study incorporated data from 11 independent journal articles and these reports included a total of 937 patients with NSCLC. The meta-analysis results revealed that increased expression of urokinase plasminogen activator (uPA) and PA inhibitor type 1 (PAI-1) exhibited no significant association with poor OS [hazard ratio (HR)-uPA=1.07 (0.87-1.31), P=0.53; HR-PAI-1=1.02 (0.63-1.65), P=0.94]. Similarly, reduced expression of PAI type 2 (PAI-2) did not significantly correlate with poor OS [HR-PAI-2=1.58 (0.64-3.90); P=0.32]. Notably, however, a significant association was observed between increased expression levels of uPA receptor (uPAR) and poor OS for NSCLC [HR-uPAR=1.50 (1.04-2.15); P=0.03]. Therefore, the expression of uPAR in the uPA system of patients with NSCLC could be used as a novel clinical biomarker to evaluate the prognosis of NSCLC. The utilization of this biomarker may provide a platform for the further development of targeted drugs for the treatment of NSCLC.

β-Catenin Knockdown Affects Mitochondrial Biogenesis and Lipid Metabolism in Breast Cancer Cells

β-catenin plays an important role as regulatory hub in several cellular processes including cell adhesion, metabolism, and epithelial mesenchymal transition. This is mainly achieved by its dual role as structural component of cadherin-based adherens junctions, and as a key nuclear effector of the Wnt pathway. For this dual role, different classes of proteins are differentially regulated via β-catenin dependent mechanisms. Here, we applied a liquid chromatography-mass spectrometry (LC-MS/MS) approach to identify proteins modulated after β-catenin knockdown in the breast cancer cell line MCF-7. We used a label free analysis to compare trypsin-digested proteins from CTR (shCTR) and β-catenin knockout cells (shβcat). This led to the identification of 98 differentially expressed proteins, 53 of them were up-regulated and 45 down-regulated. Loss of β-catenin induced morphological changes and a significant modulation of the expression levels of proteins associated with primary metabolic processes. In detail, proteins involved in carbohydrate metabolism and tricarboxylic acid cycle were found to be down-regulated, whereas proteins associated to lipid metabolism were found up-regulated in shβcat compared to shCTR. A loss of mitochondrial mass and membrane potential was also assessed by fluorescent probes in shβcat cells with respect to the controls. These data are consistent with the reduced expression of transcriptional factors regulating mitochondrial biogenesis detected in shβcat cells. β-catenin driven metabolic reprogramming resulted also in a significant modulation of lipogenic enzyme expression and activity. Compared to controls, β-catenin knockout cells showed increased incorporation of [1-¹⁴C]acetate and decreased utilization of [U-¹⁴C]glucose for fatty acid synthesis. Our data highlight a role of β-catenin in the regulation of metabolism and energy homeostasis in breast cancer cells.

Expression of HAX1 and Ki-67 in breast cancer and its correlations with patient's clinicopathological characteristics and prognosis

OBJECTIVE

This study aimed to investigate the HS-1-associated protein X-1 (HAX1) and Ki-67 expression in the breast cancer and its clinical significance.

METHODS

Breast cancer tissues and tumor-adjacent tissues were collected from 81 patients, and immunohistochemistry was conducted to detect the HAX1 and Ki-67 expression. The correlations of HAX1 expression with demographics, clinicopathological characteristics and prognosis were evaluated.

RESULTS

HAX1 was highly expressed in the breast cancer, and its expression was related to the degree of breast cancer differentiation (P=0.002), lymph nodes metastasis (P=0.008) and progesterone receptor (PR) (P=0.021), but not with the age, tumor size, histological type, estrogen receptor (ER), HER2 and p53. HAX1 expression was positively related to Ki-67 expression in the breast cancer (r(2)=0.394, P=0.019). In addition, a higher HAX-1 expression was related to a lower 10-year survival rate.

CONCLUSION

HAX1 is a new protein related to the breast cancer and probably plays an important role in the invasion and metastasis of breast cancer. Thus, HAX1 may be used as a potential target for the therapy of breast cancer.

SPRY1 promotes the degradation of uPAR and inhibits uPAR-mediated cell adhesion and proliferation

Urokinase plasminogen activator receptor (uPAR) is a GPI anchored cell surface protein that is closely associated with invasion, migration, and metastasis of cancer cells. Many functional extracellular proteins and transmembrane receptors interact with uPAR. However, few studies have examined the association of uPAR with cytoplasm proteins. We previously used yeast two-hybrid screening to isolate several novel uPAR-interacting cytoplasmic proteins, including Sprouty1 (SPRY1), an inhibitor of the (Ras-mitogen-activated protein kinase) MAPK pathway. In this study, we show that SPRY1 interacts with uPAR and directs it toward lysosomal-mediated degradation. Overexpression of SPRY1 decreased the cell surface and cytoplasmic uPAR protein level. Moreover, SPRY1 overexpression augmented uPAR-induced cell adhesion to vitronectin as well as proliferation of cancer cells. Our results also further support the critical role of SPRY1 contribution to tumor growth. In a subcutaneous tumor model, overexpression of SPRY1 in HCT116 or A549 xenograft in athymic nude mice led to great suppression of tumor growth. These results show that SPRY1 may affect tumor cell function through direct interaction with uPAR and promote its lysosomal degradation.

Hax-1 is required for Rac1-Cortactin interaction and ovarian carcinoma cell migration

Hax-1 is a multifunctional protein, which is involved in diverse cellular signaling pathways including tumor cell survival and migration. We have shown previously that cell migration stimulated by the oncogenic G protein, G_13, requires Hax-1 for the formation of a functional complex involving Gα₁₃, Rac1, and cortactin. However, the role of Hax-1 in cancer cell migration or its role in Rac1-cortactin complex formation, which is known to be required for such migration remains to be characterized. Results focused on resolving the role of Hax-1 in ovarian cancer pathophysiology indicate that Hax-1 is overexpressed in ovarian cancer cells and the silencing of Hax-1 inhibits lysophosphatidic acid (LPA)- or fetal bovine serum-stimulated migration of these cells. In addition, silencing of Hax-1 greatly reduces Rac1-cortactin interaction and their colocalization in SKOV3 cells. Mapping the structural domains of Hax-1 indicates that it interacts with cortactin via domains spanning amino acids 1 to 56 (Hax-D1) and amino acids 113 to 168 (Hax-D3). Much weaker interaction with cortactin was also observed with the region of Hax-1 spanning amino acids 169 – 224 (Hax-D4). Similar mapping of Hax-1 domains involved in Rac1 interaction indicates that it associates with Rac1 via two primary domains spanning amino acids 57 to 112 (Hax-D2) and 169 to 224 (Hax-D4). Furthermore, expression of either of these domains inhibits LPA-mediated migration of SKOV3 cells, possibly through their ability to exert competitive inhibition on endogenous Hax-1-Rac1 and/or Hax-1-cortactin interaction. More significantly, expression of Hax-D4 drastically reduces Rac1-cortactin colocalization in SKOV3 cells along with an attenuation of LPA-stimulated migration. Thus our results presented here describe for the first time that Hax-1 interaction is required for the association between Rac1 and cortactin and that these multiple interactions are required for the LPA-stimulated migration of SKOV3 ovarian cancer cells.

Involvement of urokinase-type plasminogen activator system in cancer: an overview

Currently, there are several studies supporting the role of urokinase-type plasminogen activator (uPA) system in cancer. The association of uPA to its receptor triggers the conversion of plasminogen into plasmin. This process is regulated by the uPA inhibitors (PAI-1 and PAI-2). Plasmin promotes degradation of basement membrane and extracellular matrix (ECM) components as well as activation of ECM latent matrix metalloproteases. Degradation and remodeling of the surrounding tissues is crucial in the early steps of tumor progression by facilitating expansion of the tumor mass, release of tumor growth factors, activation of cytokines as well as induction of tumor cell proliferation, migration, and invasion. Hence, many tumors showed a correlation between uPA system component levels and tumor aggressiveness and survival. Therefore, this review summarizes the structure of the uPA system, its contribution to cancer progression, and the clinical relevance of uPA family members in cancer diagnosis. In addition, the review evaluates the significance of uPA system in the development of cancer-targeted therapies.

Human Sprouty1 suppresses growth, migration, and invasion in human breast cancer cells

Breast cancer is the most common cancer and the leading cause of cancer death in women worldwide. Expression of human Sprouty1 (hSpry1) gene is downregulated in most breast cancer patients, implicating it as an important tumor suppressor gene. So, we hypothesized that overexpression of hSpry1 gene may suppress breast cancer cell growth, migration, and invasion. Here, we demonstrate that in breast cancer cell lines, MDA-MB-231 and T47D, transfection-induced overexpression of hSpry1 reduced cell population, proliferation, and colony formation in vitro without affecting cell apoptosis. Adhesion molecules act as both positive and negative modulators of cellular migration and invasion. Here, we found that overexpression of hSpry1 enhances the initial establishment events in breast cancer cell adhesion to type IV collagen and vitronectin. Moreover, the overexpression of hSpry1 in the highly invasive MDA-MB-231 breast cancer cells causes a significant reduction in cellular migration and invasion through Matrigel membranes. In addition, we showed that hSpry1 overexpression prevents VEGF secretion. VEGF is essential for primary tumor growth, migration, and invasion. Thus, our study provides a novel mechanism of tumor suppression activity of hSpry1.

Human sprouty1 suppresses urokinase receptor-stimulated cell migration and invasion

The urokinase-type plasminogen activator receptor (uPAR) has been implicated in several processes in tumor progression including cell migration and invasion in addition to initiation of signal transduction. Since uPAR lacks a transmembrane domain, it uses the interaction with other proteins to modulate intracellular signal transduction. We have previously identified hSpry1 as a partner protein of uPAR, suggesting a physiological role for hSpry1 in the regulation of uPAR signal transduction. In this study, hSpry1 was found to colocalize with uPAR upon stimulation with epidermal growth factor (EGF), urokinase (uPA), or its amino terminal fragment (uPA-ATF), implicating a physiological role of hSpry1 in regulation of uPAR signalling pathway. Moreover, hSpry1 was able to inhibit uPAR-stimulated cell migration in HEK293/uPAR, breast carcinoma, and colorectal carcinoma cells. In addition, hSpry1 was found to inhibit uPAR-stimulated cell invasion in breast carcinoma and osteosarcoma cell lines. Increasing our understanding of how hSpry1 negatively regulates uPAR-stimulated cellular functions may determine a distinctive role for hSpry1 in tumour suppression.

The critical role of dysregulated FOXM1-PLAUR signaling in human colon cancer progression and metastasis

PURPOSE

The mammalian Forkhead Box (Fox) transcription factor FOXM1 is implicated in tumorigenesis including mouse intestinal cancer. However, the clinical significance of FOXM1 signaling in human colorectal cancer pathogenesis remains unknown.

EXPERIMENTAL DESIGN

We investigated FOXM1 expression in 203 cases of primary colon cancer and matched normal colon tissue specimens and explored the underlying mechanisms of altered FOXM1 expression and the impact of this altered expression on colon cancer growth and metastasis using in vitro and animal models of colon cancer.

RESULTS

We found weak expression of FOXM1 protein in the colon mucosa, whereas we observed strong FOXM1 expression in tumor-cell nuclei of colon cancer and lymph node metastases. A Cox proportional hazards model revealed that FOXM1 expression was an independent prognostic factor in multivariate analysis. Experimentally, overexpression of FOXM1 by gene transfer significantly promoted the growth and metastasis of colon cancer cells in orthotopic mouse models, whereas knockdown of FOXM1 expression by siRNA did the opposite. Promotion of colon tumorigenesis by FOXM1 directly and significantly correlated with activation of urokinase-type plasminogen activator receptor (PLAUR) expression and elevation of invasion and metastasis.

CONCLUSIONS

Given the importance of FOXM1 in regulation of the expression of genes key to cancer biology, dysregulated expression and activation of FOXM1 may play important roles in colon cancer progression and metastasis.

Differential roles of uPAR in peritoneal ovarian carcinomatosis

Epithelial ovarian cancer is the fourth leading cause of death from gynecologic malignancies in the United States. Most cases are diagnosed at late stages, with the solid tumor masses growing as peritoneal implants, or floating within the ascitic fluid (peritoneal ovarian carcinomatosis). Despite aggressive surgical "debulking," recurrence of recalcitrant disease is frequent with poor patient survival. Efforts to improve survival rates are hindered by lack of biomarkers that can detect and effectively treat ovarian cancer in its early stages. Urokinase plasminogen activator receptor (uPAR) is a multifunctional receptor involved in a myriad of tumor cell processes. However, the role of host uPAR in ovarian cancer is still elusive. To define the potential proinflammatory role of uPAR in ovarian cancer, first, using a syngeneic murine model in uPAR(-/-) mice, we found that ablation of uPAR restrained tumor take and peritoneal implants and prolonged the survival of uPAR(-/-) mice compared with their uPAR(+/+) counterparts. Ascitic fluid accumulation was significantly decreased in uPAR(-/-) mice with decreased macrophage infiltration. Second, in vitro mechanistic studies revealed that host uPAR is involved in the multiple steps of peritoneal metastatic cascade. Third, we evaluated the prognostic utility of tumor and stromal uPAR in human ovarian cancer tissue microarray. In summary, our studies indicated that uPAR plays a significant role in ovarian cancer cell-stromal crosstalk and contributes to increased vascular permeability and inflammatory ovarian cancer microenvironment. This provides a rationale for targeting the uPAR with either specific neutralizing antibodies or targeting its downstream inflammatory effectors in patients with ovarian cancer.