Production of Cyr61 protein is modulated by extracellular acidification and PI3K/Akt signaling in prostate carcinoma PC-3 cells

Dual roles of FAK in tumor angiogenesis: A review focused on pericyte FAK

Focal adhesion kinase (FAK), also known as protein tyrosine kinase 2 (PTK2), is a ubiquitously expressed non-receptor tyrosine kinase, that plays a pivotal role in integrin-mediated signal transduction. Endothelial FAK is upregulated in many types of cancer and promotes tumorigenesis and tumor progression. However, recent studies have shown that pericyte FAK has the opposite effect. This review article dissects the mechanisms, by which endothelial cells (ECs) and pericyte FAK regulate angiogenesis, with an emphasis on the Gas6/Axl pathway. In particular, this article discusses the role of pericyte FAK loss on angiogenesis during tumorigenesis and metastasis. In addition, the existing challenges and future application of drug-based anti-FAK targeted therapies will be discussed to provide a theoretical basis for further development and use of FAK inhibitors.

Discovery of canine drug toceranib phosphate as a repurposed agent against human hepatocellular carcinoma

BACKGROUND AND AIMS

Human hepatocellular carcinoma (HCC) is an aggressive malignancy with poor clinical outcomes. There are limited therapeutic options for those diagnosed with terminal HCC and therefore incorporating novel agents into standard-of-care regimens is urgently needed. In contrast to de novo drug discovery, the strategy of repurposing compounds initially designed to treat animals might yield substantial advantages in terms of efficacy and safety. Given the evidence for the clinical efficacy of toceranib phosphate (TOC) against canine carcinomas, we aimed to investigate its therapeutic effect on human HCC.

METHODS

The antitumor effects of TOC were evaluated using human HCC cell lines and cell-line-derived xenograft models. Changes in autophagic response upon TOC exposure were quantified through immunoblotting and immunofluorescence analysis. The role of TOC-triggered autophagy was addressed via pharmacological and genetic inhibition.

RESULTS

We demonstrated TOC exhibited potent antitumor activity against human HCC cells by stimulating apoptosis in vitro and in vivo by a concomitant increase in autophagic flux. Blocking the TOC-triggered autophagy inhibited cellular proliferation and decreased tumour burden, indicating a protective role of autophagy against TOC-mediated HCC cell death. This role played by TOC-induced autophagy was further linked to the inactivation of the Akt/mTOR pathway that could be attributed to the upregulation of Cyr61. Moreover, treatment with sorafenib plus TOC resulted in pronounced synergistic effects on HCC cells.

CONCLUSION

Our results elucidate a newly identified therapeutic potential of TOC in treating HCC, sparking a growing interest in repurposing such canine drugs for human use.

Dexamethasone and lenvatinib inhibit migration and invasion of non-small cell lung cancer by regulating EKR/AKT and VEGF signal pathways

Migration and invasion is one of the most important features in tumor metastasis and development. Non-small cell lung cancer (NSCLC) is one of the most common types of cancer globally, and has been linked to air contamination. Evidence indicates that cysteine-rich angiogenic inducer 61 (CYR61) is associated with the migration and invasion of NSCLC. Overexpression of CYR61 protein promotes the migration and the transition of tumor-derived vascular endothelial cells in NSCLC. However, the association between CYR61 and NSCLC remains poorly understood. Lenvatinib is an oral multi-target drug that targets various receptors upon tumor angiogenesis. Dexamethasone is widely approved for combination therapy in patients with NSCLC. In the current study, the expression and function of CYR61 in NSCLC was analyzed during the progression of NSCLC. Inhibitory effects on migration and invasion induced by lenvatinib and dexamethasone were determined by migratory and invasion assays. Migratory pathways of extracellular signal-regulated kinases (ERK) and protein kinase B (AKT) were also investigated by targeting vascular endothelial growth factor (VEGF) and CYR61 via synergistic treatment with transforming growth factor-β1 (TGF-β1) and dexamethasone. Therapeutic outcomes of combined treatment with lenvatinib and dexamethasone were assessed in NSCLC-bearing mice. The results of the present study indicate that cooperative treatment of lenvatinib and dexamethasone significantly inhibited TGF-β1-induced cell migration and suppressed tumor growth (P<0.01). Notably, the results demonstrated that dexamethasone eradicated the promotion effects of TGF-β1 on the AKT/epithelial-mesenchymal transition process and lenvatinib extinguished tumor cell metastasis by targeting VEGF. The results of the current study also demonstrate that dexamethasone suppressed the expression of CAG-I and enhanced expression of matrix metalloproteinase-1. Synergistic treatment for NSCLC was demonstrated to be efficacious. In conclusion, dexamethasone inhibited AKT/ERK phosphorylation and lenvatinib antagonism bound VEGF leading to the limitation of migration and invasion of cancer cells in NSCLC.

Cyr61 decreases Cytarabine chemosensitivity in acute lymphoblastic leukemia cells via NF-κB pathway activation

Elevated Cyr61 levels have been reported in various malignancies. Elevation of Cyr61 protein levels contributes to the proliferation, metastasis, and chemotherapy resistance of malignant cells. Previously, it was discovered that Cyr61 is elevated in both the plasma and the bone marrow supernatants of patients with acute lymphoblastic leukemia (ALL), promoting ALL cell survival. However, the role of Cyr61 in the chemotherapeutic resistance of ALL cells remains unknown. The aim of the current study was to investigate the role of Cyr61 in regulating ALL cell chemosensitivity to Ara‑C. It was found that Cyr61 is overexpressed in bone marrow mononuclear cells from patients with ALL. Increased Cyr61 effectively decreased Ara‑C‑induced apoptosis of ALL cells, and its function was blocked by the use of the anti‑Cyr61 monoclonal antibody 093G9. Furthermore, Cyr61 increased the level of Bcl‑2 in Ara‑C‑treated ALL cells. Mechanistically, it was shown that Cyr61 affected ALL cell resistance to Ara‑C partially via the NF‑κB pathway. Taken together, the present study is the first, to the best of our knowledge, to reveal that Cyr61 is involved in ALL cell resistance through the NF‑κB pathway. The findings support a functional role for Cyr61 in promoting chemotherapy resistance, suggesting that targeting Cyr61 directly or its relevant effector pathways may improve the clinical responses of patients with ALL.

Targeting cysteine-rich angiogenic inducer-61 by antibody immunotherapy suppresses growth and migration of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the most frequent type of human lung cancer; lung cancer is responsible for the highest rates of cancer-associated mortality in the world. Cysteine-rich angiogenic inducer-61 (CYR-61) has been identified as a tumorigenesis-, development- and metastasis-related gene, and is reported to enhance proliferation, migration and invasion through hepatocyte growth factor (HGF)-induced scattering and the metastasis-inducing HGF/Met signaling pathway in tumor cells and xenograft models. CYR-61 is a protein that promotes human lung cancer cell metastasis and is closely related to the patient's prognosis in NSCLC. The purpose of the present study was to investigate whether CYR-61 may serve as a dual potential target for gene therapy of human NSCLC. In the present study, an antibody targeted against CYR-61 (anti-CYR-61) was constructed and the therapeutic effects and underlying mechanism of this antibody in NSCLC cells and mice with NSCLC was investigated. It was observed that NSCLC cell viability, migration and invasion were inhibited while cell apoptosis was induced by the neutralization of CYR-61 protein by anti-CYR-61. Western blotting demonstrated that extracellular signal-regulated kinase (ERK) and protein kinase B (AKT) expression levels in NSCLC cells were decreased following treatment with anti-CYR-61. In addition, it was observed that inhibition of NSCLC cell viability was achieved by the suppression of the epithelial-mesenchymal transition signaling pathway. ERK and AKT phosphorylation levels were downregulated in NSCLC cells and tumors following anti-CYR-61 treatment. Analysis of a murine model indicated that tumor growth was inhibited and tumor metastasis was significantly suppressed (P<0.01) following anti-CYR-61 treatment for CYR-61. In conclusion, CYR-61 may serve as a potential target for gene therapy for the treatment of human NSCLC.

Cariporide Enhances the DNA Damage and Apoptosis in Acid-tolerable Malignant Mesothelioma H-2452 Cells

The Na+/H+ exchanger is responsible for maintaining the acidic tumor microenvironment through its promotion of the reabsorption of extracellular Na+ and the extrusion of intracellular H+. The resultant increase in the extracellular acidity contributes to the chemoresistance of malignant tumors. In this study, the chemosensitizing effects of cariporide, a potent Na+/H+-exchange inhibitor, were evaluated in human malignant mesothelioma H-2452 cells preadapted with lactic acid. A higher basal level of phosphorylated (p)-AKT protein was found in the acid-tolerable H-2452AcT cells compared with their parental acid-sensitive H-2452 cells. When introduced in H-2452AcT cells with a concentration that shows only a slight toxicity in H-2452 cells, cariporide exhibited growth-suppressive and apoptosis-promoting activities, as demonstrated by an increase in the cells with pyknotic and fragmented nuclei, annexin V-PE(+) staining, a sub-G0/G1 peak, and a G2/M phase-transition delay in the cell cycle. Preceding these changes, a cariporide-induced p-AKT down-regulation, a p53 up-regulation, an ROS accumulation, and the depolarization of the mitochondrial-membrane potential were observed. A pretreatment with the phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002 markedly augmented the DNA damage caused by the cariporide, as indicated by a much greater extent of comet tails and a tail moment with increased levels of the p-histone H2A.X, p-ATMSer1981, p-ATRSer428, p-CHK1Ser345, and p-CHK2Thr68, as well as a series of pro-apoptotic events. The data suggest that an inhibition of the PI3K/AKT signaling is necessary to enhance the cytotoxicity toward the acid-tolerable H-2452AcT cells, and it underlines the significance of proton-pump targeting as a potential therapeutic strategy to overcome the acidic-microenvironment-associated chemotherapeutic resistance.

7,8-DHF Treatment Induces Cyr61 Expression to Suppress Hypoxia Induced ER Stress in HK-2 Cells

Acute kidney injury (AKI) is a common syndrome which is strongly linked to high morbidity and mortality. Hypoxia is the leading cause of AKI and the proximal renal tubular cells are the most damaged part in the kidney during this period. It has been observed that 7,8-dihydroxyflavone (7,8-DHF) plays a protective role by acting on antiapoptosis and antioxidative stress. In this study we explored functions of 7,8-DHF in protecting human proximal tubular cell line HK-2 from hypoxia insults. We observed that treatment of 7,8-DHF could improve the viability of ischemic cell. Mechanistically, we found that 7,8-DHF could elevate the expression of cysteine-rich protein 61 (Cyr61), a protective immediate early gene in AKI. In addition, treatment of 7,8-DHF decreased CCAAT/enhancer-binding protein homologous protein (CHOP) expression, which is a marker protein during endoplasmic reticulum (ER) stress activation. Intriguingly, overexpression of Cyr61 significantly reduced CHOP expression. Taken together, our results provide novel insights into the possible protective role of 7,8-DHF by activating Cyr61 signaling and suppressing ER stress in hypoxic HK-2 cells which have potential clinical implications for the treatment of AKI.

Dexamethasone Inhibits TGF-β1-Induced Cell Migration by Regulating the ERK and AKT Pathways in Human Colon Cancer Cells Via CYR61

PURPOSE

One of the features in cancer development is the migration of cancer cells to form metastatic lesions. CYR61 protein promotes migration and the epithelial-mesenchymal transition in several cancer cell types. Evidence suggests that CYR61 and dexamethasone are relevant to colorectal cancer. However, relationships between them and colorectal cancer are still unclear. Understanding the molecular mechanism of colorectal cancer progression related with CYR61 and dexamethasone, which is widely used for combination chemotherapy, is necessary for improved therapy.

MATERIALS AND METHODS

We used colorectal cancer cells, HCT116, co-treated with transforming growth factor β1 (TGF-β1) and dexamethasone to examine the inhibitory migration effect of dexamethasone by migratory assay. Alternatively, both migratory pathways, expression of AKT and ERK, and the target factor CYR61 was also tested by co-treatment with TGF-β1 and dexamethasone.

RESULTS

We report that dexamethasone significantly inhibited TGF-β1-induced cell migration, without affecting cell proliferation. Importantly, we observed that TGF-β1 promoted the epithelial-mesenchymal transition process and that dexamethasone co-treatment abolished this effect. ERK and AKT signaling pathways were found to mediate TGF-β1-induced migration, which was inhibited by dexamethasone. In addition, TGF-β1 treatment induced CYR61 expression whereas dexamethasone reduced it. These observations were compatible with the modulation of migration observed following treatment of HCT116 cells with human recombinant CYR61 and anti-CYR61 antibody. Our results also indicated that TGF-β1 enhanced collagen I and reduced matrix metalloproteinase 1 expression, which was reversed by dexamethasone treatment.

CONCLUSION

These findings suggested that dexamethasone inhibits AKT and ERK phosphorylation, leading to decreased CYR61 expression, which in turn blocks TGF-β1-induced migration.