Min Xu

Tanshinone IIA ameliorates seawater exposure-induced lung injury by inhibiting aquaporins (AQP) 1 and AQP5 expression in lung

Aquaporins (AQPs), a family of transmembrane water channels, mediate physiological response to changes of fluid volume and osmolarity. It is still unknown what role of AQPs plays in seawater drowning-induced acute lung injury (ALI) and whether pharmacologic modulation of AQPs could alleviate the severity of ALI caused by seawater aspiration. In our study, the results from RT-PCR and Western blotting showed that intratracheal installation of seawater up-regulated the mRNA and protein levels of AQP1 and AQP5 in lung tissues. Furthermore, we found that treatment of tanshinone IIA (TIIA, one of the main active components from Chinese herb Danshen) significantly reduced the elevation of AQP1 and AQP5 expression induced by seawater in rats, A549 cells and primary alveolar type II cells. Treatment of TIIA also improved lung histopathologic changes and blood-gas indices, and reduced lung edema and vascular leakage. These findings demonstrated that AQP1 and AQP5 might play an important role in the development of lung edema and lung injury, and that treatment with TIIA could significantly alleviate seawater exposure-induced ALI, which was probably through the inhibition of AQP1 and AQP5 over-expression in lungs.

HIF-1α and HIF-2α correlate with migration and invasion in gastric cancer

Hypoxia-inducible factor-1(HIF-1) is a major determinant of invasion and metastasis in several tumor types. We previously reported that HIF-1α contributed to multidrug resistance in gastric cancer. However, the role of HIF-2α on progression of gastric cancer is seldom reported. In this study, we firstly examined the possible role of HIF-1α and HIF-2α in the process of invasiveness and metastasis of gastric cancer, using immunohistochemistry of 80 gastric cancer tissues, Western blot and real-time PCR of 8 fresh gastric cancer tissues. The results showed that HIF-1α and HIF-2α significantly correlated with clinical stage and were highly expressed in metastatic gastric cancers compared to nonmetastatic ones. Western blot analysis revealed that hypoxia (1% O2, 8 h) induced HIF-1α and HIF-2α expression in different gastric cancer cell lines, including SGC7901, AGS, MGC803, and MKN45. Adhesion and invasion assays found that hypoxia caused an increase in adhesive and invasive abilities of gastric cancer cells. Small interfering ( si ) RNA against HIF-1α and HIF-2α in SGC7901 cells significantly inhibited hypoxia-induced adhesive and invasive abilities. Finally, the JNK inhibitor SP600125 abolished hypoxia-induced HIF-1α and HIF-2α expression, and inhibited the adhesive and invasive abilities of gastric cancer cells exposed to hypoxia in a dose-dependent manner. Taken together, the present work suggested that HIF-1α and HIF-2α were involved in metastasis and invasion of gastric cancer cells under hypoxia, with the involvement of JNK signal pathway.

Beta-estradiol attenuates hypoxic pulmonary hypertension by stabilizing the expression of p27kip1 in rats

BackgroundPulmonary vascular structure remodeling (PVSR) is a hallmark of pulmonary hypertension. P27kip1, one of critical cyclin-dependent kinase inhibitors, has been shown to mediate anti-proliferation effects on various vascular cells. Beta-estradiol (β-E2) has numerous biological protective effects including attenuation of hypoxic pulmonary hypertension (HPH). In the present study, we employed β-E2 to investigate the roles of p27kip1 and its closely-related kinase (Skp-2) in the progression of PVSR and HPH.MethodsSprague-Dawley rats treated with or without β-E2 were challenged by intermittent chronic hypoxia exposure for 4 weeks to establish hypoxic pulmonary hypertension models, which resemble moderate severity of hypoxia-induced PH in humans. Subsequently, hemodynamic and pulmonary pathomorphology data were gathered. Additionally, pulmonary artery smooth muscle cells (PASMCs) were cultured to determine the anti-proliferation effect of β-E2 under hypoxia exposure. Western blotting or reverse transcriptional polymerase chain reaction (RT-PCR) were adopted to test p27kip1, Skp-2 and Akt-P changes in rat lung tissue and cultured PASMCs.ResultsChronic hypoxia significantly increased right ventricular systolic pressures (RVSP), weight of right ventricle/left ventricle plus septum (RV/LV+S) ratio, medial width of pulmonary arterioles, accompanied with decreased expression of p27kip1 in rats. Whereas, β-E2 treatment repressed the elevation of RVSP, RV/LV+S, attenuated the PVSR of pulmonary arterioles induced by chronic hypoxia, and stabilized the expression of p27kip1. Study also showed that β-E2 application suppressed the proliferation of PASMCs and elevated the expression of p27kip1 under hypoxia exposure. In addition, experiments both in vivo and in vitro consistently indicated an escalation of Skp-2 and phosphorylated Akt under hypoxia condition. Besides, all these changes were alleviated in the presence of β-E2.ConclusionsOur results suggest that β-E2 can effectively attenuate PVSR and HPH. The underlying mechanism may partially be through the increased p27kip1 by inhibiting Skp-2 through Akt signal pathway. Therefore, targeting up-regulation of p27kip1 or down-regulation of Skp-2 might provide new strategies for treatment of HPH.

Lentivirus-delivered Krüppel-like factor 8 small interfering RNA inhibits gastric cancer cell growth in vitro and in vivo

We found that the transcription factor Krüppel-like factor 8 (KLF8) was highly expressed in gastric cancer tissues and cell lines compared with adjacent noncancerous regions and gastric epithelial mucosa cells. We employed a lentivirus-mediated RNAi technique to knockdown KLF8 expression in gastric cancer cell line SGC7901 and observed its effects on cell growth in vitro and in vivo. Knockdown of KLF8 inhibited SGC7901 cell proliferation, promoted cell apoptosis, inhibited the tumorigenicity of SGC7901 cells, and significantly decreased tumor growth when the cells were injected into nude mice. These results indicated that overexpression of KLF8 may influence the biological behavior of SGC7901 gastric cancer cells. Knockdown of KLF8 expression by lentivirus-delivered siRNA may be useful as a therapeutic agent for the treatment of gastric cancer.

Tanshinone IIA modulates pulmonary vascular response to agonist and hypoxia primarily via inhibiting Ca2+ influx and release in normal and hypoxic pulmonary hypertension rats

The present study was designed to investigate the vascular effects and underlying mechanisms of tanshinone IIA on isolated rat pulmonary artery. Isometric tension was recorded in the arteries from normal and hypoxic pulmonary hypertension rats under normoxia or hypoxia condition. The results showed that tanshinone IIA exerted a biphasic effect on rat pulmonary artery. The constriction was attenuated by endothelium-denudation but was enhanced by inhibition of nitric oxide synthase. Pretreatment with tetraethylammonium (Ca2+-activated K+ channel inhibitor) upward shifted the concentration-response curve without affecting the maximum dilatation. Pretreatment with zinc protoporphyrin IX (heme oxygenase-1 inhibitor), 4-aminopyridine (KV channel inhibitor), glibenclamide (KATP channel inhibitor) or BaCl2 (inwardly rectifying K+ channel inhibitor) did not affect the vasoreactivity. Meanwhile, tanshinone IIA almost abolished vasoconstriction induced by extracellular Ca2+. Under hypoxia condition, tanshinone IIA eliminated acute hypoxia-induced initial contraction, potentiated following vasorelaxation, attenuated and reversed sustained contraction to relaxation in pulmonary artery from normal rats, and reversed phenylephrine-induced sustained constriction to sustained relaxation in remodeled pulmonary artery from hypoxic pulmonary hypertension rats. We concluded that the mild constrictive effect induced by tanshinone IIA was affected by integrity of endothelium and production of nitric oxide, while the potent dilative effect was endothelium-independent and produced primarily by inhibiting extracellular Ca2+ influx and partially by inhibiting intracellular Ca2+ release, as well as activating Ca2+-activated K+ channels. The modulation of tanshinone IIA on pulmonary vasoreactivity under both acute and chronic hypoxia condition may provide a new insight for curing hypoxic pulmonary hypertension.

Role of Macrophage Migration Inhibitory Factor in the Proliferation of Smooth Muscle Cell in Pulmonary Hypertension

Pulmonary hypertension (PH) contributes to the mortality of patients with lung and heart diseases. However, the underlying mechanism has not been completely elucidated. Accumulating evidence suggests that inflammatory response may be involved in the pathogenesis of PH. Macrophage migration inhibitory factor (MIF) is a critical upstream inflammatory mediator which promotes a broad range of pathophysiological processes. The aim of the study was to investigate the role of MIF in the pulmonary vascular remodeling of hypoxia-induced PH. We found that MIF mRNA and protein expression was increased in the lung tissues from hypoxic pulmonary hypertensive rats. Intensive immunoreactivity for MIF was observed in smooth muscle cells of large pulmonary arteries (PAs), endothelial cells of small PAs, and inflammatory cells of hypoxic lungs. MIF participated in the hypoxia-induced PASMCs proliferation, and it could directly stimulate proliferation of these cells. MIF-induced enhanced growth of PASMCs was attenuated by MEK and JNK inhibitor. Besides, MIF antagonist ISO-1 suppressed the ERK1/2 and JNK phosphorylation induced by MIF. In conclusion, the current finding suggested that MIF may act on the proliferation of PASMCs through the activation of the ERK1/2 and JNK pathways, which contributes to hypoxic pulmonary hypertension.

Tanshinone IIA–Induced Attenuation of Lung Injury in Endotoxemic Mice Is Associated with Reduction of Hypoxia-Inducible Factor 1α Expression

Inhibiting hypoxia-inducible factor (HIF)-1α activity has been proposed as a novel therapeutic target in LPS-induced sepsis syndrome. We have reported that tanshinone IIA (TIIA) can reduce LPS-induced lethality and lung injury in mice, but the precise mechanisms have not been fully described. Therefore, the present study investigated whether the protective effect of TIIA was related to the inhibition of LPS-induced HIF-1α expression and what mechanisms accounted for it. This study showed that TIIA pretreatment improved LPS-induced biochemical and cellular changes and reduced the production of inflammatory cytokines. Pretreatment with TIIA decreased LPS-induced HIF-1α expression in vivo and in vitro. TIIA did not affect the LPS-induced HIF-1α mRNA level but inhibited HIF-1α protein translation by the inhibition of the PI3K/AKT and MAPK pathways and related protein translational regulators, such as p70S6K1, S6 ribosomal protein, 4E-BP1, and eIF4E, and promoted HIF-1α protein degradation via the proteasomal pathway in LPS-stimulated macrophages. These observations partially explain the antiinflammatory effects of TIIA, which provides scientific basis for its application for the treatment of acute lung injury/acute respiratory distress syndrome or sepsis.

Zinc finger E-box binding homeobox 1 promotes invasion and bone metastasis of small cell lung cancer in vitro and in vivo

Bone is one of the most frequent targets of small cell lung cancer (SCLC) metastasis and is closely associated with a poor prognosis, but the specific cellular gene alterations responsible for SCLC with bone metastasis are unclear. Zinc finger E‐box binding homeobox 1 (ZEB1) as an E‐box transcriptional repressor has been suggested that an important inducer of the epithelial‐mesenchymal transition (EMT) and a promoter of tumor metastasis in colon, breast and lung cancers. However, the relationship between ZEB1 and SCLC with bone metastasis is unclear. In this study, ZEB1 was found to be highly expressed in bone‐metastatic SCLC tissues and cell lines as compared with those that were non‐metastatic (P < 0.05). Using a lentivirus RNA interference technique to knockdown ZEB1 expression in bone‐metastatic SCLC cells (SBC‐5 cell line), we found that ZEB1 siRNA could inhibit the invasive and migratory ability and decrease parathyroid hormone‐related protein expression, as determined by invasion assays and enzyme‐linked immunosorbent assays. Besides, ZEB1 siRNA significantly inhibited the bone metastasis of SBC‐5 cells in vivo. Furthermore, overexpression of ZEB1 in SBC‐3 cells, which demonstrate promoted bone‐metastatic potential, dramatically promoted their invasive and migratory ability and parathyroid hormone‐related proteinexpression as well as increased the number and sites of bone metastases in vivo compare to the control group. We also found that SBC‐3 cells underwent EMT, as indicated by decreased epithelial markers and increased mesenchymal marker expression. Taken together, these results indicate that ZEB1 promoted the invasive ability and bone metastasis of SCLC cells, and that this was partially mediated via the EMT pathway. (Cancer Sci, doi: 10.1111/j.1349‐7006.2012.02347.x, 2012)

Tanshinone IIA suppresses lung injury and apoptosis, and modulates protein kinase B and extracellular signal-regulated protein kinase pathways in rats challenged with seawater exposure.

1. Tanshinone IIA (TIIA) is one of the main active components of the Chinese herb, Danshen. In the present study, we investigated the role of apoptosis in seawater exposure‐induced acute lung injury (ALI), and explored the effects of TIIA on lung injury, apoptosis, and protein kinase B (Akt) and etracellular signal‐regulated protein kinase (ERK) pathways in seawater‐challenged rats. The rats were randomly divided into four groups: (i) naive group, no drug was given; (ii) TIIA control group, TIIA (50 mg/kg) was given intraperitoneally; (iii) seawater (SW) group, seawater (4 mL/kg) was given; and (iv) TIIA/SW group, TIIA (50 mg/kg) was injected intraperitoneally 10 min after seawater instillation.

Effects of PerClot® on the healing of full-thickness skin wounds in rats

PerClot(®) is a hemostatic material made of polysaccharide from modified starch and has been shown to assist in topical hemostasis. The principal goal in treating surgical and non-surgical wounds is the need for rapid closure of the lesion. This study investigated whether topical application of PerClot(®) could improve impaired wound healing in Sprague-Dawley (SD) rats. Full-thickness skin wounds were created on the back of the rats. Immediately, PerClot(®) was introduced into the wound bed, while wounds receiving starch or nothing served as controls. Wound closure was monitored using well-recognized wound-healing parameters: histological examination for inflammatory cells and fibroblast infiltration, newly formed capillaries, and collagen deposition. Meanwhile, transforming growth factor (TGF-β1) was measured by immunochemistry. Wound closure was significantly accelerated by local application of PerClot(®). Furthermore, PerClot(®)-treated wounds showed significantly increased fibroblast numbers at 5 days post-wounding, and newly formed capillaries at 7 days post-wounding, and collagen regeneration at 7 and 14 days post-wounding. The number of infiltrating fibroblasts expressing TGF-β1 was significantly higher than that in the controls at 7 and 14 days post-wounding. PerClot(®) can improve the wound healing and this effect might involve an increase in the activity of fibroblasts and increased release of TGF-β1.