Jiangchao Li

P-Selectin-Mediated Adhesion between Platelets and Tumor Cells Promotes Intestinal Tumorigenesis in Apc(Min/+) Mice.

Studies have indicated that platelets play an important role in tumorigenesis, and an abundance of platelets accumulate in the ovarian tumor microenvironment outside the vasculature. However, whether cancer cells recruit platelets within intestinal tumors and how they signal adherent platelets to enter intestinal tumor tissues remain unknown. Here, we unexpectedly found that large numbers of platelets were deposited within human colorectal tumor specimens using immunohistochemical staining, and these platelets were fully associated with tumor development. We further report the robust adhesion of platelet aggregates to tumor cells within intestinal tumors, which occurs via a mechanism that is dependent on P-selectin (CD62P), a cell adhesion molecule that is abundantly expressed on activated platelets. Using spontaneous intestinal tumor mouse models, we determined that the genetic deletion of P-selectin suppressed intestinal tumor growth, which was rescued by the infusion of wild-type platelets but not P-selectin-/- platelets. Mechanistically, platelet adhesion to tumor cells induced the secretion of vascular endothelial growth factor (VEGF) to promote angiogenesis and accelerate intestinal tumor cell proliferation. Our results indicate that the adherence of platelets to tumor cells could promote tumor growth and metastasis. By targeting this platelet-tumor cell interaction, recombinant soluble P-selectin may have therapeutic value for the treatment of intestinal tumors.

MicroRNA-146 up-regulation predicts the prognosis of non-small cell lung cancer by miRNA in situ hybridization

Non-small cell lung cancer (NSCLC) accounts for approximately 70% of all lung cancer-related deaths worldwide. Prognostic markers are essential for the early detection of lung cancer in patients. In this study, we first identified microRNA146 (miR-146) expression in cancer cell lines using miRNA in situ hybridization (MISH) and confirmed the accuracy of MISH using q-RT-PCR. In addition, two different systems, BCIP/NBT and ELF, were used to detect the signal for a comparative analysis of the specificity of MISH. Compared to the BCIP/NBT system, the ELF detection system was more effective for MISH. Furthermore we detected the expression of miR-146 in NSCLC tissues (43 cases) and normal tissues (32 cases). Based on our results, we can conclude that miR-146 is more highly expressed in cancer tissue than normal tissue (t-test, P<0.05) and that miR-146 can predict the prognosis of NSCLC by MISH. Our findings preliminary demonstrate that MISH can be applied as a molecular diagnostic tool to determine the expression and localization of miRNAs in cancer tissues and that miR-146, determined by MISH, predicts the prognosis of NSCLC patients.

P-Selectin-Mediated Platelet Adhesion Promotes the Metastasis of Murine Melanoma Cells

Studies have indicated that the aggregation of activated platelets with cancer cells facilitates tumor metastasis; the adhesion molecule P-selectin may be an important mediator of this process, but the detailed mechanism is unclear. In the current study, we established a B16F10 (B16) cell metastatic model in P-selectin knockout (P-sel−/−) mice to determine the effect of P-selectin-mediated platelet adhesion on metastasis. Compared with C57 mice, P-sel−/− mice developed fewer metastatic foci, and cell proliferation within the metastatic tumors was inhibited by P-selectin deficiency. The platelet refusion assay demonstrated that mice with P-sel−/− platelets developed fewer lung metastatic foci (P<0.01) with a lower microvascular density (MVD) than mice with wild-type platelets. A co-culture model of platelets and B16 cells was utilized to determine the difference in VEGF concentration in the supernatants. The results demonstrated that the supernatant from the P-sel−/− platelet/B16 co-culture had a lower concentration of VEGF. Therefore, our findings indicated that P-selectin deficiency inhibited the metastasis of B16 cells and that wild-type platelet refusion reversed this inhibition. The P-selectin-mediated interaction between platelets and B16 cells promoted angiogenesis by up-regulating VEGF.

Andrographolide inhibits melanoma tumor growth by inactivating the TLR4/NF-κB signaling pathway.

The TLR4/NF-&kgr;B signaling pathway plays a critical role in tumor progression. Andrographolide (Andro) has been reported to have anticancer activity in multiple types of cancer. However, the pharmacological activities of Andro in melanoma are not completely understood. In this study, we defined the anticancer effects of Andro in melanoma and elucidated its potential mechanisms of action. Our experiments showed that Andro significantly inhibited melanoma tumor growth and metastasis by inducing cell cycle arrest and apoptosis. In addition, Andro significantly inhibited the TLR4/NF-&kgr;B signaling pathway. Furthermore, the inactivation of TLR4/NF-&kgr;B signaling inhibited the mRNA and protein expression of CXCR4 and Bcl-6, which are antitumor genes. This work provides evidence that the TLR4/NF-&kgr;B signaling pathway is a potential therapeutic target and may also be indispensable in the Andro-mediated anticancer effect in melanoma.

Autophagy is involved in high glucose-induced heart tube malformation

Both pre-gestational and gestational diabetes have an adverse impact on heart development, but little is known about the influence on the early stage of heart tube formation. Using early gastrulating chick embryos, we investigated the influence of high glucose on the process of heart tube formation, specifically during the primary heart field phase. We demonstrated that high-glucose exposure resulted in 3 types of heart tube malformation: 1) ventricular hypertrophy, 2) ventricular hypertrophy with dextrocardia and 3) ventricular hypertrophy and dextrocardia with the fusion anomaly of a bilateral primary heart tube. Next, we found that these malformation phenotypes of heart tubes might mainly originate from the migratory anomaly of gastrulating precardiac mesoderm cells rather than cell proliferation in the developmental process of bilateral primary heart field primordia. The treatment of rapamycin (RAPA), an autophagy inducer, led to a similar heart tube malformation phenotype as high glucose. Additionally, high-glucose exposure promoted the expression of the key autophagy protein LC3B in early chick tissue. Atg7 is strongly expressed in the fusion site of bilateral primary heart tubes. All of these data imply that autophagy could be involved in the process of high-glucose-induced malformation of the heart tube.

SAP deficiency mitigated atherosclerotic lesions in ApoE / mice

OBJECTIVE Serum amyloid P conpoent (SAP), a member of the pentraxin family, interact with pathogens and cell debris to promote their removal by macrophages and neutrophils and is co-localized with atherosclerotic plaques in patients. However, the exact mechanism of SAP in atherogenesis is still unclear. We investigated whether SAP influence macrophage recruitment and foam cell formation and ultimately affect atherosclerotic progression. METHODS we generated apoE(-/-); SAP(-/-) (DKO) mice and fed them western diet for 4 and 8 weeks to characterize atherosclerosis development. RESULTS SAP deficiency effectively reduced plaque size both in the aorta (p = 0.0006 for 4 wks; p = 0.0001 for 8 wks) and the aortic root (p = 0.0061 for 4 wks; p = 0.0079 for 8wks) compared with apoE(-/-) mice. Meanwhile, SAP deficiency inhibited oxLDL-induced foam cell formation (p = 0.0004) compared with apoE(-/-) mice and SAP treatment increases oxLDL-induced foam cell formation (p = 0.002) in RAW cells. Besides, SAP deficiency reduced macrophages recruitment (p = 0.035) in vivo and in vitro (p = 0.026). Furthermore, SAP treatment enhanced CD36 (p = 0.007) and FcγRI (p = 0.031) expression induced by oxLDL through upregulating JNK and p38 MAPK phosphorylation whereas specific JNK1/2 inhibitor reduced CD36 (p = 0.0005) and FcγRI (P = 0.0007) expression in RAW cell. SAP deficiency also significantly decreased the expression of M1 and M2 macrophage markers and inflammatory cytokines in oxLDL-induced macrophages. CONCLUSION SAP deficiency mitigated foam cell formation and atherosclerotic development in apoE(-/-) mice, due to reduction in macrophages recruitment, polarization and pro-inflammatory cytokines and inhibition the CD36/FcγR-dependent signaling pathway.

Increased Permeability of the Blood-Brain Barrier and Alzheimer's Disease-Like Alterations in Slit-2 Transgenic Mice

Alzheimers disease (AD) is a progressive neurological disorder that primarily affects memory, and its prevalence is rising. Increasing evidence suggests that dysfunction of the blood-brain barrier (BBB) may be involved in AD and other neurodegenerative diseases. Herein, we report that the permeability of the BBB is increased and that AD-like alterations are present in Slit-2 overexpressing transgenic mice. We found that behavioral change and the corresponding molecular diagnostic markers of AD, such as hippocampal neuron apoptosis, amyloid-β (Aβ) protein deposition, and acetylcholinesterase expression, were increased in the Slit-2 transgenic mice. Moreover, the endothelial cells were dysfunctional, the size of the lateral ventricle cavity increased, and the permeability of the BBB increased. Additionally, there was an increased serum level of glutamate indicating that the BBB is related to AD. Finally, histopathological analysis of other organs in the Slit-2 overexpressing mice did not show any marked abnormalities. These findings demonstrate that Slit2 overexpression may be responsible for AD-like alterations and the increased BBB permeability in these mice. Our study provides a potential novel mechanism for the development of AD.

Activation of Slit2-Robo1 signaling promotes liver fibrosis.

BACKGROUND & AIMS The secretory protein Slit2 and its receptor Robo1 are believed to regulate cell growth and migration. Here, we aimed to determine whether Slit2-Robo1 signaling mediates the pathogenesis of liver fibrosis. METHODS Serum levels of Slit2 in patients with liver fibrosis were determined by ELISA. Liver fibrosis was induced in wild-type (WT), Slit2 transgenic (Slit2-Tg) and Robo1(+/-)Robo2(+/-) double heterozygotes (Robo1/2(+/-)) mice by carbon tetrachloride (CCl4). The functional contributions of Slit2-Robo1 signaling in liver fibrosis and activation of hepatic stellate cells (HSCs) were investigated using primary mouse HSCs and human HSC cell line LX-2. RESULTS Significantly increased serum Slit2 levels and hepatic expression of Slit2 and Robo1 were observed in patients with liver fibrosis. Compared to WT mice, Slit2-Tg mice were much more vulnerable to CCl4-induced liver injury and more readily develop liver fibrosis. Development of hepatic fibrosis in Slit2-Tg mice was associated with a stronger hepatic expression of collagen I and α-smooth muscle actin (α-SMA). However, liver injury and hepatic expression of collagen I and α-SMA were attenuated in CCl4-treated Robo1/2(+/-) mice in response to CCl4 exposure. In vitro, Robo1 neutralizing antibody R5 and Robo1 siRNA downregulated phosphorylation of Smad2, Smad3, PI3K, and AKT in HSCs independent of TGF-β1. R5 and Robo1 siRNA also inhibited the expression of α-SMA by HSCs. Finally, the protective effect of R5 on the CCl4-induced liver injury and fibrosis was further verified in mice. CONCLUSIONS Slit2-Robo1 signaling promotes liver injury and fibrosis through activation of HSCs.

Andrographolide suppresses high glucose-induced fibronectin expression in mesangial cells via inhibiting the AP-1 pathway

Mesangial cells (MCs) proliferation and accumulation of glomerular matrix proteins such as fibronectin (FN) are the early features of diabetic nephropathy, with MCs known to upregulate matrix protein synthesis in response to high glucose. Recently, it has been found that andrographolide has renoprotective effects on diabetic nephropathy. However, the molecular mechanism underlying these effects remains unclear. Cell viability and proliferation was evaluated by MTT. FN expression was examined by immunofluorescence and immunoblotting. Activator protein‐1 (AP‐1) activation was assessed by immunoblotting, luciferase reporter and electrophoretic mobility shift assays. Andrographolide significantly decreased high glucose‐induced cell proliferation and FN expression in MCs. Exposure of MCs to high glucose markedly stimulated the expression of phosphorylated c‐jun, whereas the stimulation was inhibited by andrographolide. Plasmid pAP‐1‐Luc luciferase reporter assay showed that andrographolide blocked high glucose‐induced AP‐1 transcriptional activity. EMSA assay demonstrated that increased AP‐1 binding to an AP‐1 binding site at −1,029 in the FN gene promoter upon high glucose stimulation, and the binding were disrupted by andrographolide treatment. These data indicate that andrographolide suppresses high glucose‐induced FN expression by inhibiting AP‐1‐mediated pathway. J. Cell. Biochem. 114: 2562–2568, 2013.

Robo1/2 regulate follicle atresia through manipulating granulosa cell apoptosis in mice.

Secreted Slit proteins and their Roundabout (Robo) receptors act as a repulsive cue to preventaxons from migrating to inappropriate locations during the development of the nervous system. Slit/Robo has also been implicated in reproductive system development, but the molecular mechanism of the Slit/Robo pathway in the reproductive system remains poorly understood. Using a transgenic mouse model, we investigated the function of the Slit/Robo pathway on ovarian follicle development and atresia. We first demonstrated that more offspring were born to mice with a partial knockout of the Robo1/2 genes in mice. We next showed that Robo1 and Robo2 are strongly expressed in ovarian granulosacells. Apoptosis in granulosa cells was reduced when Robo1/2 were partially knocked out, and this observation was further verified by in vitro Robo1/2 knockout experiments in mouse and human granulosa cells. We also found that ovarian angiogenesis wasenhanced by a partial lack of Robo1/2 genes. In summary, our data suggest that the Slit/Robo pathway can impact follicle development and atresia by influencinggranulosa cell apoptosis.