CCL2 increases αvβ3 integrin expression and subsequently promotes prostate cancer migration

Background

Chemokine ligand 2 (CCL2), also known as monocyte chemoattractant protein-1 (MCP-1), belongs to the CC chemokine family which is associated with the disease status and outcomes of cancers. Prostate cancer is the most commonly diagnosed malignancy in men and shows a predilection for metastasis to the bone. However, the effect of CCL2 on human prostate cancer cells is largely unknown. The aim of this study was to examine the role of CCL2 in integrin expression and migratory activity in prostate cancers.

Methods

Prostate cancer migration was examined using Transwell, wound healing, and invasion assay. The PKCδ and c-Src phosphorylations were examined by using western blotting. The qPCR was used to examine the mRNA expression of integrins. A transient transfection protocol was used to examine AP-1 activity.

Results

Stimulation of prostate cancer cell lines (PC3, DU145, and LNCaP) induced migration and expression of integrin αvβ3. Treatment of cells with αvβ3 antibody or siRNA abolished CCL2-increased cell migration. CCL2-increased migration and integrin expression were diminished by CCR2 but not by CCR4 inhibitors, suggesting that the CCR2 receptor is involved in CCL2-promoted prostate cancer migration. CCL2 activated a signal transduction pathway that includes PKCδ, c-Src, and AP-1. Reagents that inhibit specific components of this pathway each diminished the ability of CCL2 to effect cell migration and integrin expression.

Conclusions

Interaction between CCL2 and CCR2 enhances migration of prostate cancer cells through an increase in αvβ3 integrin production.

General significance

CCL2 is a critical factor of prostate cancer metastasis.     

High glucose induces vascular endothelial growth factor production in human synovial fibroblasts through reactive oxygen species generation

Background

Diabetes is an independent risk factor of osteoarthritis (OA). Angiogenesis is essential for the progression of OA. Here, we investigated the intracellular signaling pathways involved in high glucose (HG)-induced vascular endothelial growth factor (VEGF) expression in human synovial fibroblast cells.

Methods

HG-mediated VEGF expression was assessed with qPCR and ELISA. The mechanisms of action of HG in different signaling pathways were studied using Western blotting. Knockdown of proteins was achieved by transfection with siRNA. Chromatin immunoprecipitation assays were used to study in vivo binding of c-Jun to the VEGF promoter.

Results

Stimulation of OA synovial fibroblasts (OASF) with HG induced concentration- and time-dependent increases in VEGF expression. Treatment of OASF with HG increased reactive oxygen species (ROS) generation. Pretreatment with NADPH oxidase inhibitor (APO or DPI), ROS scavenger (NAC), PI3K inhibitor (Ly294002 or wortmannin), Akt inhibitor, or AP-1 inhibitor (curcumin or tanshinone IIA) blocked the HG-induced VEGF production. HG also increased PI3K and Akt activation. Treatment of OASF with HG increased the accumulation of phosphorylated c-Jun in the nucleus, AP-1-luciferase activity, and c-Jun binding to the AP-1 element on the VEGF promoter.

Conclusions

Our results suggest that the HG increases VEGF expression in human synovial fibroblasts via the ROS, PI3K, Akt, c-Jun and AP-1 signaling pathway.

General significance

We link high glucose on VEGF expression in osteoarthritis.     

Palmitate-derivatized human IL-2: a potential anticancer immunotherapeutic of low systemic toxicity

Purpose and experimental design

Recombinant human IL-2 (rhIL-2) is a potent cytokine and FDA-approved anticancer drug. However, its clinical use has been limited by severe toxicity, associated primarily with systemic administration with excess protein distributing freely throughout the body. We hypothesized that rhIL-2 in alternate forms permitting more restricted localization may exert stronger antitumor efficacy and less toxicity. Here, we have tested the utility of palmitate-derivatized rhIL-2. rhIL-2 was reacted with N-hydroxysuccinimide palmitate ester. The resultant lipidated rhIL-2 (pIL-2), when mixed with cells, could spontaneously transfer from solution to cell surfaces. Next, anticancer efficacy of pIL-2 was assessed in two modalities. For adoptive T cell therapy, antitumor cytotoxic T cells (CTLs) were protein transferred (“painted”) with pIL-2 and injected into mice bearing lymphoma. For in situ therapy, pIL-2 was injected intratumorally into mice bearing melanoma. Tumor growth and IL-2-associated toxicity were determined.

Results

In the lymphoma model, painting of the antitumor CTLs with pIL-2 markedly increased their viability and titer. In the melanoma model, intratumoral injection of pIL-2, but not rhIL-2, increased the number of activated CD8⁺ T cells (IFN-γ⁺) in the spleen, reduced lung metastasis and prolonged the survival of treated mice. Moreover, while repeated intratumoral injection of rhIL-2 at an excessively high dose (10 injections of 10,000 IU/mouse) caused marked vascular leakage syndrome, the same regimen using pIL-2 caused no detectable toxicity.

Conclusions

Transferring spontaneously from solution to cell surfaces, pIL-2 may bypass the current limitations of rhIL-2 and, thus, serve as a more effective and tolerable anticancer drug.     

Association of polymorphisms in the Chr18q11.2 locus with tuberculosis in Chinese population

A GWAS study has reported that two single nucleotide polymorphisms (SNPs) were associated with predisposition to tuberculosis (TB) in African populations. These two loci represented the long-waited GWAS hits for TB susceptibility. To determine whether these two SNPs are associated with TB in Chinese population, we attempted an replication in a cohort of over one thousand Chinese TB patients and 1,280 healthy controls using melting temperature shift allele-specific genotyping analysis. We found that only SNP rs4331426 was significantly associated with TB in Chinese population (p = 0.011). However, the effect was opposite. The G allele of the SNP in Chinese population is a protective allele (OR = 0.62, 95 % CI 0.44–0.87), while it was the risk allele for African population (OR = 1.19, 95 % CI 1.12–1.26). No significance was found for SNP rs2335704. The results provided an independent support for a role in susceptibility to TB for SNP rs4331426. However, it also indicated that direct predisposition element to TB and the association effects may vary across ethnic groups.     

Mast cells expressing interleukin 17 in the muscularis propria predict a favorable prognosis in esophageal squamous cell carcinoma

The proinflammatory cytokine interleukin 17 (IL-17) is considered to play a crucial role in diverse human tumors; however, its role in disease progression remains controversial. This study investigated the cellular source and distribution of IL-17 in esophageal squamous cell carcinoma (ESCC) in situ and determined its prognostic value. Immunohistochemistry, immunofluorescence and immunoelectron microscopy were used to identify IL-17-expressing cells in ESCC tissues, paying particular attention to their anatomic localization. Kaplan–Meier analysis and Cox proportional hazards regression models were applied to estimate overall survival in 215 ESCC patients with long-term follow-up (>10 years). The results showed that mast cells, but not T cells or macrophages, were the predominant cell type expressing IL-17 in ESCC tissues. Unexpectedly, these IL-17⁺ cells were highly enriched in the muscularis propria rather than the corresponding tumor nest (p < 0.0001). The density of IL-17⁺ cells in muscularis propria was inversely associated with tumor invasion (p = 0.016) and served as an independent predictor of favorable survival (p = 0.007). Moreover, the levels of IL-17⁺ cells in muscularis propria were positively associated with the density of effector CD8⁺ T cells and activated macrophages in the same area (both p < 0.0001). This finding suggested that mast cells may play a significant role in tumor immunity by releasing IL-17 at a previously unappreciated location, the muscularis propria, in ESCC tissues, which could serve as a potential prognostic marker and a novel therapeutic target for ESCC.     

Inhibition of ROS-Activated p38MAPK Pathway is Involved in the Protective Effect of H2S Against Chemical Hypoxia-Induced Inflammation in PC12 Cells

We have demonstrated the neuroprotection of hydrogen sulfide (H₂S) against chemical hypoxia-induced injury by inhibiting p38MAPK pathway. The present study attempts to evaluate the effect of H₂S on chemical hypoxia-induced inflammation responses and its mechanisms in PC12 cells. We found that treatment of PC12 cells with cobalt chloride (CoCl₂, a hypoxia mimetic agent) enhanced IL-6 secretion, nitric oxide (NO) generation and expression levels of inducible nitric oxide synthase (iNOS) and neuronal nitric oxide synthase (nNOS). L-canavanine, a selective iNOS inhibitor, partly blocked CoCl₂-induced cytotoxicity, apoptosis and mitochondrial insult. In addition, 7-Nitroindazole (7-NI), an inhibitor of nNOS, also partly attenuated the CoCl₂-induced cytotoxicity. The inhibition of p38MAPK by SB203580 (a selective p38MAPK inhibitor) or genetic silencing of p38MAPK by RNAi (Si-p38) depressed not only CoCl₂-induced iNOS expression, NO production, but also IL-6 secretion. In addition, N-acetyl-l-cysteine, a reactive oxygen species (ROS) scavenger, conferred a similar protective effect of SB203580 or Si-p38 against CoCl₂-induced inflammatory responses. Importantly, pretreatment of PC12 cells with exogenous application of sodium hydrosulfide (a H₂S donor, 400 μmol/l) for 30 min before exposure to CoCl₂ markedly attenuated chemical hypoxia-stimulated iNOS and nNOS expression, NO generation and IL-6 secretion as well as p38MAPK phosphorylation in PC12 cells. Taken together, we demonstrated that p38MAPK-iNOS pathway contributes to chemical hypoxia-induced inflammation and that H₂S produces an anti-inflammatory effect in chemical hypoxia-stimulated PC12 cells, which may be partly due to inhibition of ROS-activated p38MAPK-iNOS pathway.     

Slow Regulated Release of H2S Inhibits Oxidative Stress Induced Cell Death by Influencing Certain Key Signaling Molecules

Hydrogen sulphide (H₂S) is one of three gaseous signaling molecules after nitric oxide and carbon monoxide. Various H₂S donor compounds have been synthesized to study its physiological function. Among these compounds sodium hydrosulphide (NaHS), a donor of releasing H₂S rapidly have shown to be protective in certain neuronal cell line but several in vivo studies have generated conflicting data. Furthermore several slow releasing H₂S donors have been shown to have positive effects on cells in culture. The intracellular concentration of H₂S and hence its rate of production may be a factor in keeping the balance between its neuroprotective and toxic effects. The present study was undertaken to deduce how a rapid releasing H₂S donor (NaHS) as opposed to a slow releasing donor (ADTOH), affect oxidative stress related intracellular components and survival of RGC-5 cells. It was concluded that when RGC-5 cells are exposed to the toxic effects of glutamate in combination with buthionine sulfoxime (Glu/BSO), ADTOH was more efficacious in inhibiting apoptosis, scavenging reactive oxygen species (ROS), stimulation of glutathione (GSH) and gluthathione-S-transferase (GST). Western blot and qPCR analysis showed ADTOH increased the levels of Nrf2, HO-1, PKCα, p-Akt, Bcl-2 and XIAP but caused a decrease of Nfκβ and xCT greater than NaHS. This study is first to compare the efficacy of two H₂S donor drugs as potential neuroprotectants and demonstrate that slow regulated release of H₂S to cell culture can be more beneficial in inhibiting oxidative stress induced cell death.