Methanolic extract of Euchelus asper exhibits in-ovo anti-angiogenic and in vitro anti-proliferative activities

BACKGROUND: The marine environment is a rich source of bioactive natural products. Many of the marine bioactive compounds have been derived successfully from molluscs. Euchelus asper is a marine mollusc which is commonly found in the intertidal rocky regions of the Mumbai coast. The present study was focused on evaluating the anti-angiogenic and anti- proliferative activities of methanolic extract of Euchelus asper (EAME). METHODS: The anti-angiogenic activity of EAME (50-800 µg/mL) was assessed by chick chorio-allantoic membrane (CAM) model wherein multiple parameters in the CAM blood vessels were analysed through morphometric and histo-logical investigations. In vitro testing of EAME (5-20 µg/mL) included its cytotoxicity against three different cancer cell lines, its effect on cell proliferation by wound healing assay as well as their relevant molecular mechanisms. Statistical analysis was carried out by two-tailed student's t test for two unpaired groups. RESULTS: Analysis of CAM revealed that the extract is effective in reducing the branching points of the 1st order blood vessels or capillaries of CAM. Histological analysis of CAM showed significant decrease in capillary plexus and compartmentalization along with increase in mesodermal blood vessels, thus establishing its anti-angiogenicity. Further, EAME exhibited moderate but significant cytotoxicity against A549 non-small cell lung carcinoma cell line. We also demonstrated that the cytotoxicity of EAME in A549 was associated with its apoptotic activity by subG1 phase arrest. Lastly, EAME significantly reduced A549 proliferation by reducing the expression of Matrix metalloproteinase-2 (MMP-2) and Matrix metalloproteinase-9 (MMP-9). CONCLUSION: Overall, our study suggested that EAME has potential to inhibit tumour angiogenic and proliferative activity and may be a potential source for development of new anti-cancer pharmaceuticals.

Ethyl-p-methoxycinnamate isolated from kaempferia galanga inhibits inflammation by suppressing interleukin-1, tumor necrosis factor-α, and angiogenesis by blocking endothelial functions

OBJECTIVE: The present study aimed to investigate the mechanisms underlying the anti-inflammatory and anti-angiogenic effects of ethyl-p-methoxycinnamate isolated from Kaempferia galanga. METHODS: The anti-inflammatory effects of ethyl-p-methoxycinnamate were assessed using the cotton pellet granuloma assay in rats, whereby the levels of interleukin-1 and tumor necrosis factor-α were measured in the animals' blood. In addition, the levels of interleukin, tumor necrosis factor, and nitric oxide were measured in vitro using the human macrophage cell line (U937). The analgesic effects of ethyl-p-methoxycinnamate were assessed by the tail flick assay in rats. The anti-angiogenic effects were evaluated first by the rat aortic ring assay and, subsequently, by assessing the inhibitory effects of ethyl-p-methoxycinnamate on vascular endothelial growth factor, proliferation, migration, and tube formation in human umbilical vein endothelial cells. RESULTS: Ethyl-p-methoxycinnamate strongly inhibited granuloma tissue formation in rats. It prolonged the tail flick time in rats by more than two-fold compared with the control animals. The inhibition of interleukin and tumor necrosis factor by ethyl-p-methoxycinnamate was significant in both in vivo and in vitro models; however, only a moderate inhibition of nitric oxide was observed in macrophages. Furthermore, ethyl-p-methoxycinnamate considerably inhibited microvessel sprouting from the rat aorta. These mechanistic studies showed that ethyl-p-methoxycinnamate strongly inhibited the differentiation and migration of endothelial cells, which was further confirmed by the reduced level of vascular endothelial growth factor. CONCLUSION: Ethyl-p-methoxycinnamate exhibits significant anti-inflammatory potential by inhibiting pro-inflammatory cytokines and angiogenesis, thus inhibiting the main functions of endothelial cells. Thus, ethyl-p-methoxycinnamate could be a promising therapeutic agent ...

Comparative in vivo antiangiogenic effects of calreticulin from Trypanosoma cruzi and Homo sapiens sapiens

Angiogenesis is a complex multi-step process of neovascularization arising from preexisting blood vessels whose generation is regulated by pro- and anti-angiogenic factors. Both Trypanosoma cruzi calreticulin (TcCRT) and its human counterpart (HuCRT) are antiangiogenic. This is the first report where the TcCRT and HuCRT anti-angiogenic properties are compared in vivo. In the chick embryonic chorioallantoid membrane assay (CAM) and at equimolar concentrations, TcCRT displayed significantly higher antiangiogenic activities than its human counterpart. LPS had marginal effects at the concentrations present in the recombinant protein preparations and the TcCRT antiangiogenic effects were largely inhibited by specific polyclonal antibodies, thus, reinforcing the fact that the observed TcCRT effects can be attributed to the parasite-derived molecule and not to the endotoxin. The antiangiogenic TcCRT effects correlate with its anti-tumor in vivo effects, as recently shown in our laboratory.

Fatty acids derived from a marine crustacean Diogenes avarus (Heller) and their antiangiogenic activity.

An organic extract from a marine crustacean D. avarus was examined for antiangiogenic activity by using the chick embryo chorioallantoic membrane (CAM) assay. The methanol extract (HCM) inhibited angiogenesis in a dose dependent manner. The extract was further fractionated by bioactivity-guided separation to purify the active fractions successively. This resulted in three fractions HCM1, HCM2 and HCM3. The 50% inhibition shown by HCM was 600 ng/disc, HCM1 was 100 ng/disc and of HCM3 was 2.7ng/disc. HCM3 which was separated by column chromatography and showed single spot on TLC was analysed by GLC and showed the presence of saturated and unsaturated fatty acids such as lauric, myristic, palmitic, stearic, oleic, linoleic. The antiangiogenic activity of the fatty acids obtained from a marine crustacean is reported for the first time.

Purification and characterization of recombinant murine endostatin in E. coli

Endostatin, a carboxyl-terminal fragment of collagen XVIII is known as an anti-angiogenic agent, that specifically inhibits the proliferation of endothelial cell and the growth of several primary tumor. We report here the purification and characterization of the recombinant murine endostatin (rmEndostatin) which was expressed in a prokaryotic expression system. This rmEndostatin has similar physiochemical properties of yeast-produced recombinant endostatin, and it also specifically inhibits the proliferation and migration of bovine capillary endothelial cells stimulated by basic fibroblast growth factor. The biological activity of rmEndostatin was also shown by its anti-angiogenic ability on the chorioallantoic membrane of chick embryo in vivo. In this article, we demonstrate the refolding and purification of rmEndostatin, expressed using E. coli system, to a biologically active and soluble form. In addition, these results confirm the activity of endostatin as a potent anti-angiogenic agent. Copyright 2000 Academic Press.