DNA aptamer raised against advanced glycation end products inhibits melanoma growth in nude mice

Abstract

Epidemiological studies have suggested that diabetes is associated with an increased risk of cancer. However, the underlying molecular mechanism remains unclear. We investigated here whether DNA aptamer directed against advanced glycation end products (AGE-aptamer) inhibited melanoma growth in nude mice. G361 melanoma cells were injected intradermally into the upper flank of athymic nude mice. Mice received continuous intraperitoneal infusion (0.136 mg/day) of either AGE-aptamer (n ¼ 9) or Control-aptamer (n ¼ 8) by an osmotic mini pump. Tumor volume was measured at 4-day interval, and G361 melanoma was excised at day 43 after the aptamer treatment. We further examined the effects of AGE-aptamer on proliferation of AGE-exposed endothelial cells and G361 cells. AGE-aptamer significantly inhibited the in vivo-tumor growth of G361 melanoma. Immunohistochemical and western blotting analyses of G361 melanoma revealed that AGE-aptamer decreased expression levels of proliferating nuclear antigen, CD31 and Mac-3, markers of endothelial cells and macrophages, respectively. AGE-aptamer significantly decreased the number of tumorassociated vessels. AGE, receptor for AGE (RAGE) and vascular endothelial growth factor levels were also reduced in AGE-aptamer-treated G361 melanoma. AGE-aptamer inhibited the AGE-induced proliferation and tube formation of endothelial cells as well as the growth of G361 cells in vitro. The present findings suggest that AGE-aptamer could inhibit the AGE-RAGE axis in G361 melanoma and resultantly suppress the tumor growth in nude mice by blocking the angiogenesis. AGE-aptamer might be a novel therapeutic strategy for preventing the progression of malignant melanoma in diabetes.

RAGE-aptamer Attenuates the Growth and Liver Metastasis of Malignant Melanoma in Nude Mice

“…Six-week-old female athymic nude mice (Japan Clea, Tokyo) were used in the present experiments. Animal experiments were performed according to the following procedure (24). Two million G361 cells were intradermally administered into the upper flank of nude mice (n = 14).…”

“…HUVECs were seeded on BD Biocoat Cellware Matrigel Basement Membrane Matrix 12-well plates (BD Bioscience, Franklin Lakes, NJ, USA) and then treated with 50 µg/mL nonglycated BSA or AGE-BSA in the presence or absence of 100 nM RAGE-aptamer at 37°C for 2 h. Four microscopic fields selected at random from each well (N = 3) were photographed, and the length of tube-like structures was measured with microcomputer-assisted ImageJ (24).…”

RAGE and its ligands in cancer – culprits, biomarkers, or therapeutic targets?

“…RAGE may play a role in the metastatic switch of the melanoma cells [54]. Administration of anti-RAGE antibodies [55], or DNA AGE-aptamer (a short sequence of DNA or RNA with high affinity to cognate ligands [56]) to nude mice with infused melanoma cells significantly inhibited tumor growth, number of tumor-associated vessels and decreased expression levels of proliferating nuclear antigen [57]. Expression of RAGE, S100P and cytoskeletal protein ezrin which all play a role in tumor growth, invasion and metastasis were significantly higher (and closely correlating) in melanoma than in nevus pigmentosus and higher expression levels were observed in metastatic compared to primary melanomas [58].…”

DNA-aptamers raised against AGEs as a blocker of various aging-related disorders

“…The long-term continuous intraperitoneal injection of AGE-aptamer (clone #1, 0.136 μg/day) by an osmotic mini pump inhibited the in vivo-tumor growth of G361 melanoma in nude mice in association with reduced number of proliferating melanoma cells and tumor-related angiogenesis and macrophage infiltration [60]. Moreover, the AGE-aptamer significantly decreased expression levels of AGEs, RAGE and VEGF in G361 melanoma of nude mice, whereas it blocked the AGE-induced growth and tube formation of endothelial cells as well as G361 melanoma cell proliferation in vitro [58].…”

“…Human cultured mesangial cells [38] Inhibition of AGE-induced ROS generation and up-regulation of RAGE, MCP-1, and CTGF mRNA levels Bovine retinal pericytes [36,63] Inhibition of AGE-induced apoptosis and decrease in DNA synthesis Human umbilical vein endothelial cells [63] Inhibition of AGE-induced up-regulation of RAGE, VEGF, and PAI-1 mRNA levels Suppression of proliferation and tube formation Cultured G361 melanoma cells [60] Growth inhibition Diabetic nephropathy in type 2 diabetic mice [38] Reduction of UAE and urinary 8-OHdG levels Suppression of glomerular hypertrophy, glomerular AGE and ECM accumulation, and podocyte loss Improvement of renal dysfunction Inhibition of renal RAGE, MCP-1, TNF-α, type IV collage, and CTGF mRNA levels Diabetic retinopathy in type 1 diabetic rats [64] Reduction of serum AGE levels Improvement of decreased amplitude of a-and b-wave as well as oscillatory potentials in electroretinogram Numerous animal and human studies have shown that electrophysiologic changes in ERG, such as reduction in a-and bwave amplitudes and prolongation of peak latency of OPs are the earliest characterisc features of diabetic retinopathy, which could be observed before the appearance of ophthalmoscopically obvious lesions [65,66]. We, along with others, have previously reported that serum levels of AGEs are correlated with delay in peak latencies of OPs [65] and that blockade of the AGE-RAGE axis ameliorates abnormalities in OP implicit times in type 2 diabetic animals [67].…”