Asiatic Acid Inhibits Pro-Angiogenic Effects of VEGF and Human Gliomas in Endothelial Cell Culture Models

Chandagirikoppal V Kavitha,Chapla Agarwal,Rajesh Agarwal,Gagan Deep,Dhyan Chandra

doi:10.1371/journal.pone.0022745

Chandagirikoppal V Kavitha, Chapla Agarwal + Show 3 more

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https://doi.org/10.1371/journal.pone.0022745

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Abstract

Malignant gliomas are one of the most devastating and incurable tumors. Sustained excessive angiogenesis by glioma cells is the major reason for their uncontrolled growth and resistance toward conventional therapies resulting in high mortality. Therefore, targeting angiogenesis should be a logical strategy to prevent or control glioma cell growth. Earlier studies have shown that Asiatic Acid (AsA), a pentacyclic triterpenoid, is effective against glioma and other cancer cells; however, its efficacy against angiogenesis remains unknown. In the present study, we examined the anti-angiogenic efficacy of AsA using human umbilical vein endothelial cells (HUVEC) and human brain microvascular endothelial cells (HBMEC). Our results showed that AsA (5–20 µM) inhibits HUVEC growth and induces apoptotic cell death by activating caspases (3 and 9) and modulating the expression of apoptosis regulators Bad, survivin and pAkt-ser473. Further, AsA showed a dose-dependent inhibition of HUVEC migration, invasion and capillary tube formation, and disintegrated preformed capillary network. AsA also inhibited the VEGF-stimulated growth and capillary tube formation by HUVEC and HBMEC. Next, we analyzed the angiogenic potential of conditioned media collected from human glioma LN18 and U87-MG cells treated with either DMSO (control conditioned media, CCM) or AsA 20 µM (AsA20 conditioned media, AsA20CM). CCM from glioma cells significantly enhanced the capillary tube formation in both HUVEC and HBMEC, while capillary tube formation in both endothelial cell lines was greatly compromised in the presence of AsA20CM. Consistent with these results, VEGF expression was lesser in AsA20CM compared to CCM, and indeed AsA strongly inhibited VEGF level (both cellular and secreted) in glioma cells. AsA also showed dose-dependent anti-angiogenic efficacy in Matrigel plug assay, and inhibited the glioma cells potential to attract HUVEC/HBMEC. Overall, the present study clearly showed the strong anti-angiogenic potential of AsA and suggests its usefulness against malignant gliomas.

Highlights

Neo-angiogenesis refers to the formation of new blood vessels from existing parent vessels and is considered crucial for the transition of tumors from a dormant to malignant state [1,2]
We analyzed the angiogenic potential of conditioned media collected from human glioma LN18 and U87-MG cells treated with either DMSO or Asiatic Acid (AsA) 20 mM (AsA20 conditioned media, AsA20CM)
For the first time, we investigated the anti-angiogenic efficacy of AsA using human umbilical vein endothelial cells (HUVEC) and human brain microvascular endothelial cells (HBMEC)

Summary

Introduction

Neo-angiogenesis refers to the formation of new blood vessels from existing parent vessels and is considered crucial for the transition of tumors from a dormant to malignant state [1,2]. Avastin has shown promising pre-clinical and clinical activity against metastatic colorectal cancer in combination with fluorouracil [20,21]. It was recently approved for the treatment of recurrent gliomas [22,23]. We suggest the use of agents that are small, non-toxic, safe, affordable, and efficacious in inhibiting angiogenesis in gliomas and other cancers. In this direction, present study examines the anti-angiogenic efficacy of one such small molecule namely Asiatic Acid (AsA)

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Conclusion