- Oncol Rep. 2005 Oct;14(4):807-15.
effect of a mixture containing ascorbic acid, lysine, proline and green
tea extract on critical parameters in angiogenesis.
of extracellular matrix (ECM) is a hallmark of tumor invasion,
metastasis and angiogenesis. Based on the Rath multitargeted approach
to cancer using natural substances to control ECM stability and
enhancing its strength, we developed a novel formulation (NM) of
lysine, proline, ascorbic acid and green tea extract that has shown
significant anti-cancer activity against a number of cancer cell lines.
The aim of the present study was to determine whether NM exhibits
anti-angiogenic and anti-metastatic effects using in vitro and in vivo
experimental models. Angiogenesis was measured using a chorioallantoic
membrane (CAM) assay in chick embryos and bFGF-induced vessel growth in
C57BL/6J female mice. To determine the in vivo effect of NM on the
tumor xenograft growth, male nude mice were inoculated with 3 x 10(6)
MNNG-HOS cells. Control mice were fed a mouse chow diet, while the test
group was fed a mouse chow diet supplemented with 0.5% NM for 4 weeks.
In vitro studies on cell proliferation (MTT assay), MMP expression
(zymography) and Matrigel invasion were conducted on human osteosarcoma
U2OS, maintained in McCoy medium, supplemented with 10% FBS, penicillin
and streptomycin in 24-well tissue culture plates and tested with NM at
0, 10, 50, 100, 500, and 1000 microg/ml in triplicate at each dose. NM
at 250 microg/ml caused a significant (p<0.05) reduction in
bFGF-induced angiogenesis in CAM.
NM inhibited tumor growth of
osteosarcoma MNNG-HOS cell xenografts in nude mice by 53%; furthermore,
tumors in NM-treated mice were less vascular and expressed lower levels
of VEGF and MMP-9 immunohistochemically than tumors in the control
group. In addition, NM exhibited a dose-dependent inhibition of
osteosarcoma U2OS cell proliferation (up to 60% at 1000 microg/ml),
MMP-2 and -9 expression (with virtual total inhibition at 500 microg/ml
NM), and invasion through Matrigel (with total inhibition at 100
microg/ml NM). Moreover, NM decreased U2OS cell expression of VEGF,
angiopoietin-2, bFGF, PDGF and TGFbeta-1.
These results together with
our earlier findings suggest that NM is a relatively non-toxic
formulation, which inhibits growth, invasion, metastasis, and
angiogenesis of tumor cells.