Effect of arsenic trioxide on vascular endothelial cell proliferation and expression of vascular endothelial growth factor receptors Flt-1 and KDR in gastric cancer in nude mice. World J Gastroenterol. 2007;13:6498-6505. [PMID: 18161919 DOI: 10.3748/wjg.13.6498]

Potential molecular mechanisms underlying the effect of arsenic on angiogenesis

Arsenic is a potent chemotherapeutic drug that is applied as a treatment for cancer; it exerts its functions through multiple pathways, including angiogenesis inhibition. As angiogenesis is a critical component of the progression of many diseases, arsenic is a feasible treatment option for patients with other angiogenic diseases, including rheumatoid arthritis and psoriasis, among others. However, arsenic is also a well-known carcinogen, demonstrating a pro-angiogenesis effect. This review will focus on the dual effects of arsenic on neovascularization and the relevant mechanisms underlying these effects, aiming to provide a rational understanding of arsenic treatment. In particular, we expect to provide a comprehensive overview of the current knowledge of the mechanisms by which arsenic influences angiogenesis.

Low dosage of arsenic trioxide inhibits vasculogenic mimicry in hepatoblastoma without cell apoptosis

Hepatoblastoma (HB) is the most common type of pediatric liver malignancy, which predominantly occurs in young children (aged <5 years), and continues to be a therapeutic challenge in terms of metastasis and drug resistance. As a new pattern of tumor blood supply, vasculogenic mimicry (VM) is a channel structure lined by tumor cells rather than endothelial cells, which contribute to angiogenesis. VM occurs in a variety of solid tumor types, including liver cancer, such as hepatocellular carcinoma. The aim of the present study was to elucidate the effect of arsenic trioxide (As₂O₃) on VM. In vitro experiments identified that HB cell line HepG₂ cells form typical VM structures on Matrigel, and the structures were markedly damaged by As₂O₃ at a low concentration before the cell viability significantly decreased. The western blot results indicated that As₂O₃ downregulated the expression level of VM-associated proteins prior to the appearance of apoptotic proteins. In vivo, VM has been observed in xenografts of HB mouse models and identified by periodic acid-Schiff⁺/CD105⁻ channels lined by HepG₂ cells without necrotic cells. As₂O₃ (2 mg/kg) markedly depresses tumor growth without causing serious adverse reactions by decreasing the number of VM channels via inhibiting the expression level of VM-associated proteins. Thus, the present data strongly indicate that low dosage As₂O₃ reduces the formation of VM in HB cell line HepG₂ cells, independent of cell apoptosis in vivo and in vitro, and may represent as a candidate drug for HB targeting VM.

VEGFA Expression Is Inhibited by Arsenic Trioxide in HUVECs through the Upregulation of Ets-2 and miRNA-126

Arsenic trioxide (ATO) has been used to treat patients with acute promyelocytic leukemia. Recently, studies have shown that ATO can induce apoptosis in leukemic cells and blood vessel endothelial cells in a time- and dose-dependent manner through the inhibition of vascular endothelial growth factor A (VEGFA) production. VEGFA is a key factor in angiogenesis initiation. Targeted inhibition of VEGF or VEGFA expression can suppress angiogenesis; however, little is known about the mechanism by which ATO inhibits VEGFA expression. In this study, we investigated the role of miRNA-126 in the mechanism of action of ATO in human umbilical vein endothelial cells (HUVECs). ATO significantly decreased the viability and proliferation of HUVECs and decreased their migration at 48 h. Cell proliferation was inhibited by 50% (IC50) when 5.0 μmol/L ATO was used. ATO treatment induced miR-126 upregulation and HUVEC apoptosis. Transfection with a miR-126 mimic significantly downregulated VEGFA mRNA levels, and transfection with a miR-126 inhibitor significantly upregulated VEGFA mRNA levels. Finally, we showed that ATO treatment upregulated Ets-2 and miR-126 expression in HUVECs. These results demonstrate that ATO inhibits the growth of HUVECs and induces apoptosis by downregulating VEGFA. One mechanism by which this occurs is Ets-2 upregulation, which results in an increase in miR-126 levels and downregulation of VEGFA expression.

Acceleration of bone-defect repair by using A-W MGC loaded with BMP2 and triple point-mutant HIF1α-expressing BMSCs

Background

The goal of this study is to explore the effects of A-W MGC (apatite-wollastonite magnetic bioactive glass-ceramic) loaded with BMP2 (bone morphogenetic protein 2)- and HIF1α^mu (hypoxia-inducible factor 1 mutation)-expressing BMSCs (bone marrow mesenchymal stem cells) on the bone defect repair.

Methods

(1) BMSCs were infected with viral solution containing BMP2 and HIF1α^mu with the best MOI (multiplicity of infection). The efficiency was observed via hrGFP (human renilla reniformis green fluorescent protein). (2) The cells were divided into five groups (A–E), and ALP (alkaline phosphatase) activity was measured. (3) BMP2 and HIF1α (hypoxia-inducible factor 1α) protein were measured. (4) A-W MGC was loaded with BMSCs that contain the genes and implanted into the bone defect model. The animals were sacrificed 8 and 12 weeks later. (5) The healing was measured with X-ray, histology, and biomechanics.

Results

(1) BMSCs in A–D showed high transfection efficiency. (2) ALP in A and B was higher than the others (p = 0.041 or 0.038); A was higher than B (p = 0.038); (3) BMP2 in A and B was higher than the others (p = 0.014). HIF1α in A and C was higher than the others (p = 0.020). (4) 8 and 12 weeks after, an X-ray indicated that bone defect was nearly fully repaired in A and C. (5) 12 weeks after, the bone remodeling was complete in A and C. (6) The flexural strength in A and C was stronger than the others (p = 0.043).

Conclusion

Engineered A-W MGC with BMP2 and HIF1α^mu-expressing BMSCs exhibits comparable therapeutic effects of bone-defect repair as an autologous bone graft.

14-Deoxyandrographolide alleviates ethanol-induced hepatosteatosis through stimulation of AMP-activated protein kinase activity in rats

Andrographis paniculata (AP) is a traditional medicinal plant of Ayurveda. It grows widely in Asia and is prescribed in the treatment of liver diseases. Here we have investigated the beneficial role of 14-deoxyandrographolide (14-DAG), a bioactive diterpenoid from AP, against alcoholic steatosis in rats. 14-DAG was extracted from aerial parts (leaves and stems) of AP. Rats were fed with ethanol for 8 weeks. Animals were treated with 14-DAG during the last 4 weeks of ethanol treatment. In vitro studies were undertaken in a human hepatocellular liver carcinoma cell line culture. Hepatosteatosis was assessed from histopathological studies of liver sections. Acetyl-CoA, malonyl-CoA, and triglyceride contents were determined using commercially available kits. Fatty acid synthesis was evaluated from incorporation of 1-(14)C acetate. Regulation of fatty acid oxidation and lipogenesis were monitored with immunoblotting and immunoprecipitation studies. Ethanol exposure led to hepatotoxicity, as evident from the marked enhancement in the levels of AST and ALT. The values decreased almost to control levels in response to 14-DAG treatment. Results showed that ethanol feeding induced deactivation of AMP-activated protein kinase (AMPK) that led to enhanced lipid synthesis and decreased fatty acid oxidation, culminating in hepatic fat accumulation. Treatment with 14-DAG activated AMPK through induction of cyclic AMP-protein kinase A pathway. Activation of AMPK was followed by down-regulation of sterol regulatory element binding protein-1c, acetyl-CoA carboxylase, and fatty acid synthase, leading to suppression of lipogenesis. This was associated with up-regulation of sirtuin 1 and depletion of malonyl-CoA, in favor of increased fatty acid oxidation. 14-DAG controlled ethanol-induced hepatosteatosis by interfering with dysregulation of lipid metabolism. In conclusion, our results indicated that 14-DAG was capable of preventing the development of fatty liver through AMPK-mediated regulation of lipid metabolism. This finding supported the hepatoprotective role of 14-DAG, which might serve as a therapeutic option to alleviate hepatosteatosis in chronic alcoholism.

14-Deoxyandrographolide targets adenylate cyclase and prevents ethanol-induced liver injury through constitutive NOS dependent reduced redox signaling in rats

Chronic alcoholism is one of the most common causes of liver diseases worldwide. Nitric oxide (NO) has been proposed to have potential for clinical application against chronic hepatocellular injuries. However, mechanisms underlying hepatoprotective functions of NO in ethanol-induced apoptosis are largely unknown. Sprauge-Dawley rats were exposed to ethanol for 8 weeks. Half of the ethanol-fed animals received 14-deoxyandrographolide (14-DAG) treatment for the last 4 weeks of study. Preventive effect of 14-DAG against ethanol-induced hepatotoxicity involved constitutive nitric oxide synthase (cNOS) activation followed by up-regulation of γ-glutamylcysteine synthetase activity and reduced oxidative stress. Enhanced interaction of cNOS with caveolin-1 caused down-regulation of enzyme activity and led to depletion of NO in the hepatocytes of ethanol-fed animals. 14-DAG acted as activator of adenylate cyclase and modulated cyclic AMP (cAMP) mediated expression of caveolin-1 and calmodulin. This eventually favored activation of cNOS through inhibition of cNOS-caveolin-1 interaction. Our results suggest that, protective effect of 14-DAG against ethanol-induced hepatic injury is based on its ability to reduce oxidative stress through cNOS dependent improvement of redox status. 14-DAG mediated activation of adenylate cyclase-cAMP signaling leading to up-regulation of cNOS may provide a promising approach in the prevention of liver diseases during chronic alcoholism.

Anticancer effect of arsenic trioxide on cholangiocarcinoma: in vitro experiments and in vivo xenograft mouse model

The purpose of our study was to investigate anticancer activity of arsenic trioxide (As2O3) on cholangiocarcinoma through in vitro and in vivo experiments using human cholangiocarcinoma cancer cells (CC-t6 cells) and a nude mouse model. The effect of As2O3 on CC-t6 cell survival was determined in vitro using MTT assay. Analysis of cell cycle phase distribution and quantification of apoptosis/necrosis, which were achieved by flow cytometry, were performed in order to understand the mechanism of As2O3. In vivo experiment was performed to assess the effectiveness of local injection of As2O3 on tumor inhibition by comparing the following three groups each consisting of five nude mouse xenograft models: high dose As2O3 (5 mg/kg), low dose As2O3 (1 mg/kg), and saline. In MTT assay, As2O3 inhibited the growth of CC-t6 cells more effectively than cisplatin or adriamycin at concentrations between 1 and 100 μM for most time points between 24 and 72 h (p < 0.05). With increased concentration of As2O3, there was dose-dependent increase in G 0/G 1 phase and dose-dependent decrease in S phase. As2O3-mediated inhibition of cell viability was achieved via induction of apoptosis and necrosis in a dose-dependent manner. Injection of As2O3 into CC-t6-induced tumors in nude mice inhibited the growth of subcutaneous tumor xenografts. As2O3 treatment dose-dependently inhibited the proliferation of CC-t6 cells via G 0/G 1 phase arrest and retarded tumor growth in nude mice, suggesting that As2O3 may be effective in the treatment of cholangiocarcinoma.

Potential role of sodium-proton exchangers in the low concentration arsenic trioxide-increased intracellular pH and cell proliferation

Arsenic main inorganic compound is arsenic trioxide (ATO) presented in solution mainly as arsenite. ATO increases intracellular pH (pHi), cell proliferation and tumor growth. Sodium-proton exchangers (NHEs) modulate the pHi, with NHE1 playing significant roles. Whether ATO-increased cell proliferation results from altered NHEs expression and activity is unknown. We hypothesize that ATO increases cell proliferation by altering pHi due to increased NHEs-like transport activity. Madin-Darby canine kidney (MDCK) cells grown in 5 mmol/L D-glucose-containing DMEM were exposed to ATO (0.05, 0.5 or 5 µmol/L, 0–48 hours) in the absence or presence of 5-N,N-hexamethylene amiloride (HMA, 5–100 µmol/L, NHEs inhibitor), PD-98059 (30 µmol/L, MAPK1/2 inhibitor), Gö6976 (10 µmol/L, PKCα, βI and μ inhibitor), or Schering 28080 (10 µmol/L, H⁺/K⁺ATPase inhibitor) plus concanamycin (0.1 µmol/L, V type ATPases inhibitor). Incorporation of [³H]thymidine was used to estimate cell proliferation, and counting cells with a hemocytometer to determine the cell number. The pHi was measured by fluorometry in 2,7-bicarboxyethyl-5,6-carboxyfluorescein loaded cells. The Na⁺-dependent HMA-sensitive NHEs-like mediated proton transport kinetics, NHE1 protein abundance in the total, cytoplasm and plasma membrane protein fractions, and phosphorylated and total p42/44 mitogen-activated protein kinases (p42/44^mapk) were also determined. Lowest ATO (0.05 µmol/L, ∼0.01 ppm) used in this study increased cell proliferation, pHi, NHEs-like transport and plasma membrane NHE1 protein abundance, effects blocked by HMA, PD-98059 or Gö6976. Cell-buffering capacity did not change by ATO. The results show that a low ATO concentration increases MDCK cells proliferation by NHEs (probably NHE1)-like transport dependent-increased pHi requiring p42/44^mapk and PKCα, βI and/or μ activity. This finding could be crucial in diseases where uncontrolled cell growth occurs, such as tumor growth, and in circumstances where ATO, likely arsenite, is available at the drinking-water at these levels.

Feasibility of diagnosis of early gastric cancer assisted by confocal microscopy

Gastric cancer has high incidence and mortality and does serious harm to the health of human beings. Early diagnosis and radical operation are crucial for prognosis in patients with gastric cancer. Worldwide efforts have been taken to search new methods and technologies that can enable early, accurate and efficient diagnosis of gastric cancer. The birth of the confocal microscope makes the dream come true. It perfectly combines the advantages of various kinds of technologies and allows early, rapid and accurate diagnosis of gastric cancer. In this paper, we discuss the possibility of using laser confocal microscopy for the early diagnosis of gastric cancer to improve patients' life quality and survival rate.

Matrix metalloproteinase activity causes VEGFR-2 cleavage and microvascular rarefaction in rat mesentery

A complication of the spontaneously hypertensive rat (SHR) is microvascular rarefaction, defined by the loss of microvessels. However, the molecular mechanisms involved in this process remain incompletely identified. Recent work in our laboratory suggests that matrix metalloproteinases (MMPs) may play a role by cleavage of the vascular endothelial growth factor receptor 2 (VEGFR-2). In order to further delineate the role for MMPs in microvascular rarefaction, the objective of the current study was to examine the relationship in the same tissue between MMP activity, VEGFR-2 cleavage and rarefaction. Using an in vivo microzymographic technique, we show significantly enhanced levels of MMP-1, -1/-9, -7, and -8 activities, but not MMP-2 and -3 activities, along mesenteric microvessels of the SHR compared to its normotensive control, Wistar Kyoto rat. Based on immunohistochemical methods, the SHR exhibited a decreased labeling of the extracellular, but not the intracellular, domain of VEGFR-2 along mesenteric microvessels. Chronic MMP inhibition served to attenuate VEGFR-2 cleavage and microvascular network rarefaction in the SHR mesentery. These results spatially link MMP-induced VEGFR-2 cleavage and rarefaction in the mesentery of the SHR and thus support the hypothesis that MMPs serve as regulators of microvascular dysfunction in hypertension.

Prognostic significance of serum gamma-glutamyl transferase in patients with intermediate hepatocellular carcinoma treated with transcatheter arterial chemoembolization

OBJECTIVES

Not every unresectable hepatocellular carcinoma (HCC) could receive survival benefits from transcatheter arterial chemoembolization (TACE), even for intermediate HCC (Barcelona Clinic Liver Cancer stage B). The aim of this study was to investigate prognostic significance of serum γ-glutamyl transferase (GGT) in patients with intermediate HCC treated with TACE.

METHODS

A total of 277 patients with intermediate HCC were consecutively treated with TACE and overall survival (OS) was evaluated with the Kaplan-Meier method. Significant difference was estimated with the Log rank method according to GGT value before treatment. Univariate and multivariate analyses were used for the study of significance of prognostic factor.

RESULTS

The median follow-up period was 18.7 months. The 1-year and 3-year OS rates were 71.6 and 38.5% in patients with normal GGT and 48.8 and 16.9% in patients with high GGT (P=0.002). High GGT, correlating with higher tumor size, α-fetoprotein (AFP), and alanine aminotrasferase, was an independent prognostic factor for OS (P=0.009). Others included tumor size and ascites. Furthermore, in small HCC and normal AFP subgroup, serum GGT was also correlated with OS (P=0.013 and 0.041, respectively). The combination of GGT and AFP had a better power to predict the TACE effects.

CONCLUSION

GGT level was an important prognostic factor to predict prognosis of patients with intermediate HCC treated with TACE.

Thermochemotherapy effect of nanosized As2O3/Fe3O4 complex on experimental mouse tumors and its influence on the expression of CD44v6, VEGF-C and MMP-9

BACKGROUND

Both thermotherapy and arsenic have been shown to be active against a broad spectrum of cancers. To reduce the limitations of conventional thermotherapy, improve therapeutic anticancer activity, reduce the toxicity of arsenic on normal tissue, and increase tissue-specific delivery, we prepared a nanosized As2O3/Fe3O4 complex (Fe3O4 magnetic nanoparticles encapsulated in As2O3). We assessed the thermodynamic characteristics of this complex and validated the hyperthermia effect, when combined with magnetic fluid hyperthermia (MFH), on xenograft HeLa cells (human cervical cancer cell line) in nude mice. We also measured the effect on the expression of CD44v6, VEGF-C, and MMP-9 which were related to cancer and/or metastasis.

RESULTS

The nanosized As2O3/Fe3O4 particles were approximately spherical, had good dispersibility as evidenced by TEM, and an average diameter of about 50 nm. With different concentrations of the nanosized As2O3/Fe3O4 complex, the correspondingsuspension of magnetic particles could attain a steady temperature ranging from 42 degrees C to 65 degrees C when placed in AMF for 40 min. Thermochemotherapy with the nanosized As2O3/Fe3O4 complex showed a significant inhibitory effect on the mass (88.21%) and volume (91.57%) of xenograft cervical tumors (p < 0.05 for each measurement, compared with control). In addition, thermochemotherapy with the nanosized As2O3/Fe3O4 complex significantly inhibited the expression of CD44v6, VEGF-C, and MMP-9 mRNA (p < 0.05 for each).

CONCLUSION

As2O3/Fe3O4 complex combined with MFH had is a promising technique for the minimally invasive elimination of solid tumors and may be have anticancerometastasic effect by inhibiting the expression of CD44v6, VEGF-C, and MMP-9.

Adenoviral infection or deferoxamine? Two approaches to overexpress VEGF in beta-cell lines

Rapid and adequate revascularization of transplanted islets is important for their survival and function during transplantation. Vascular endothelial growth factor (VEGF) could play a critical role with respect to islet revascularization. The aim of this study was to compare two strategies that are used to overexpress VEGF in beta-cells: (1) gene therapy through adenoviral infection and (2) a pharmacological approach using deferoxamine (DFO). beta-Cell lines from rat insulinoma (RINm5F) were either infected using an adenovirus encoding the gene of human VEGF 165 or incubated with DFO. One day after treatment, the viability of RINm5F cells was preserved with 10 micromol/L of DFO (103.95 +/- 5.66% toward control; n = 4). In addition, adenoviral infection maintained the viability of cells for all the concentrations used. In both treatments, overexpression of VEGF was in a comparable level. Finally, the ratio of Bax/Bcl-2 indicated that the apoptosis increased in infected beta-cells whereas treatment with DFO seems to be antiapoptotic. Our results suggest that the use of DFO could be a realistic approach to improve the vascularization of islets during transplantation.