ABSTRACT
PURPOSE: Vascular endothelial growth factor (VEGF) signal transduction mainly depends on its binding to VEGF receptor 2 (VEGFR-2). VEGF downstream signaling proteins mediate several of its effects in cancer progression, including those on tumor growth, metastasis, and blood vessel formation. The activation of VEGFR-2 signaling is a hallmark of and is considered a therapeutic target for breast cancer. Here, we report a study of the regulation of the VEGFR-2 signaling pathway by a small molecule, isomangiferin. METHODS: A human breast cancer xenograft mouse model was used to investigate the efficacy of isomangiferin in vivo. The inhibitory effect of isomangiferin on breast cancer cells and the underlying mechanism were examined in vitro. RESULTS: Isomangiferin suppressed tumor growth in xenografts. In vitro, isomangiferin treatment inhibited cancer cell proliferation, migration, invasion, and adhesion. The effect of isomangiferin on breast cancer growth was well coordinated with its suppression of angiogenesis. A rat aortic ring assay revealed that isomangiferin significantly inhibited blood vessel formation during VEGF-induced microvessel sprouting. Furthermore, isomangiferin treatment inhibited VEGF-induced proliferation of human umbilical vein endothelial cells and the formation of capillary-like structures. Mechanistically, isomangiferin induced caspase-dependent apoptosis of breast cancer cells. Furthermore, VEGF-induced activation of the VEGFR-2 kinase pathway was down-regulated by isomangiferin. CONCLUSION: Our findings demonstrate that isomangiferin exerts anti-breast cancer effects via the functional inhibition of VEGFR-2. Pharmaceutically targeting VEGFR-2 by isomangiferin could be an effective therapeutic strategy for breast cancer.
Subject(s)
Animals , Humans , Mice , Rats , Angiogenesis Inhibitors , Apoptosis , Blood Vessels , Breast Neoplasms , Cell Proliferation , Heterografts , Human Umbilical Vein Endothelial Cells , In Vitro Techniques , Microvessels , Neoplasm Metastasis , Phosphotransferases , Receptors, Vascular Endothelial Growth Factor , Signal Transduction , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factor Receptor-2ABSTRACT
Development of small molecule drugs is important for targeted and personalized therapy for cancers.However,it is staggering to take new compounds from the research bench to clinical trial pipelines and eventually to the clinical practice,due to the time,effort and costs.Most drugs need five years of development after discovery in the laboratory before they are ready to be tested for efficacy and safety.Compared to development of new drugs from scratch, increasing research efforts have been made to turn existing drugs to new uses to treat cancers, which may bypass years of costly work.Metformin used in cancer care is a good example of giving old drugs a new life.The activity of metformin on anti-cancer has recently drawn significant attention.Epidemiological and experimental studies have shown that metformin can cut down the incidence of cancer in diabetic patients and reduce metabolism-related cancers.Meanwhile, recent study has found metformin can induce autophagy of esophageal cancer cells by inhibiting inflammatory signaling pathway.In recent years, increasing studies have shown that metformin plays a major role in suppressing cancers via multiple mechanisms.In this mini-review,we summarize the updates of the research on metformin in cancer prevention and treatment.
ABSTRACT
Objective To construct a colon cancer chemotherapy-resistant cell line COLO,and study its characteristics and its relationship with tumor stem cells.Methods We constructed two 5-fluorouraci (5-FU)-resistant colon cancer cell line COLO/5-FU-1 and COLO/5-FU-2, which were resistant to 0.1 0 μmol/ml and 0.20 μmol/ml 5-FU respectively through gradiently increased drug concentration.The cha-racteristics of 5-FU-resistant cell lines were compared with parental colon cancer cell line COLO related to proli-feration,colony forming ability,migration and invasion,sphere forming ability,expression of stemness genes and cross drug-resistance.Results In the cell viability assay,4 days after regular training,the absorbancy of colon cancer 5-FU-resistant cell lines COLO/5-FU-2,COLO/5-FU-1 and parental colon cancer cell line COLO were 0.61 ±0.1 3,0.54 ±0.07 and 0.41 ±0.09 respectively,with significant difference (F =63.43,P =0.033).With the increased concentration of 5-FU,5-FU-resistant cell lines presented increasing clonality. The cloning efficiency of COLO/5-FU-2,COLO/5-FU-1 and parental colon cancer cell line COLO were (87.6 ±1 2.7)%,(65.3 ±9.7)% and (38.5 ±7.6)% respectively,with significant difference (F =33.64, P =0.01 7).In each high power field of vision,the cell numbers of migration through the basement membrane of COLO/5-FU-2,COLO/5-FU-1 and parental colon cancer cell line COLO were 482 ±39,434 ±45 and 373 ±38 respectively;and the cell numbers of invasion through the basement membrane were 1 74 ±42,1 1 2 ± 31 and 87 ±29 respectively,with significant differences (F =1 09.61 ,P =0.009;F =67.31 ,P =0.032). Compared with parental colon cancer cell line COLO,5-FU-resistant cell lines had higher expression of stem-ness genes (F =47.31 ,P =0.042).5-FU-resistant cell lines were cross-resistant to other chemotherapeutic drugs such as mitoxantrone.For example,after incubation for 96 hours,inhibition rate of mitoxantrone to parent colon cancer cell line COLO was higher significantly than COLO/5-FU-1 and COLO/5-FU-2 (0.749 ± 0.042,0.423 ±0.024,0.342 ±0.01 8),with significant difference (F =1 2.61 ,P =0.028).The micro-sphere forming rates of COLO/5-FU-2,COLO/5-FU-1 and parental colon cancer cell line COLO were (8.90 ± 0.97)%,(6.20 ±0.75)% and (3.90 ±0.32)% respectively,with significant difference (F =1 64.32,P =0.006).Conclusion Colon cancer drug-resistant cell line COLO possess tumor stem cell-like characteristics, which are enriched in cancer stem cells.