Differential Anti-Proliferative and Anti-Migratory Activities of Ursolic Acid, 3-O-Acetylursolic Acid and Their Combination Treatments with Quercetin on Melanoma Cells.

Aljawharah Alqathama,Ammar Bader,Jose M Prieto,Proma Khondkar,Simon Gibbons,Luying Shao

doi:10.3390/biom10060894

Abstract

We evaluate how 3-acetylation modulates the in vitro activity of ursolic acid in melanoma cells alone or in combination treatments with quercetin. Anti-proliferative studies on A375 cells and adult human dermal fibroblasts included analyses on cell cycle distribution, caspase activity, phosphatidylserine translocation, cell morphology and Bax/Bcl-2 protein expression. Then, 2D and 3D migration of B16F10 cells were studied using scratch and Transwell assays, respectively. Ursolic acid and 3-O-acetylursolic acid have shown similar GI50 on A375 cells (26 µM vs. 32 µM, respectively) significantly increased both early and late apoptotic populations, activated caspases 3/7 (48–72 h), and enhanced Bax whilst attenuating Bcl-2 expression. Ursolic acid caused elevation of the sub-G1 population whilst its 3-acetyl derivative arrested cell cycle at S phase and induced strong morphological changes. Combination treatments showed that ursolic acid and quercetin act synergistically in migration assays but not against cell proliferation. In summary, 3-O-acetylursolic acid maintains the potency and overall apoptotic mechanism of the parent molecule with a more aggressive influence on the morphology of A375 melanoma cells but the 3-acetylation suppresses its anti-migratory properties. We also found that ursolic acid can act in synergy with quercetin to reduce cell migration.

Highlights

Pentacyclic terpenes such as betulinic acid, lupeol, ursolic acid, and oleanolic acids have been described as highly specific cytotoxic drugs against several cancer cells [1,2,3,4,5].The effects of ursolic acid on melanoma cells has been gaining interest for its cytotoxic with a favourable selectivity index [6,7,8]
The anti-proliferative effects were studied using the Sulforhodamine B (SRB) assay on both A375 and HDf-a cell lines (Figure 2). 3-O-acetylursolic acid and ursolic acid showed a significant time and concentration-dependent suppression of cell proliferation at 32.4 ± 1.33 μM and 26.7 ± 3.61 μM, respectively
They are comparatively non-toxic to HDf-a a shown by their relatively high GI50 concentrations (126.5 ± 24 μM for 3-O-acetylursolic acid and 89.31 ± 9.50 μM for ursolic acid)

Summary

Introduction

Pentacyclic terpenes such as betulinic acid, lupeol, ursolic acid, and oleanolic acids have been described as highly specific cytotoxic drugs against several cancer cells [1,2,3,4,5]. The effects of ursolic acid on melanoma cells has been gaining interest for its cytotoxic with a favourable selectivity index [6,7,8]. It suppresses the migration of malignant melanoma cells [9]. In the case of ursolic acid, the anti-proliferative effect was improved when a hydrogen acceptor group was introduced to poBsioimtioolnecsul3es, 21012,0,1170,axnFdO2R8PlEiEkReRaEcVetIEyWl or aminoalkyl groups, with β-oriented hydrogen-bond form2inogf 14 greoxuhpisbiattinCg-3 emxohribeitipnogtemnotrecpytootetonxticcyittyototxhiacnity tthheainr thαe-icroαu-ncoteurnptaerrtpsar(tFsi(gFuigreure11) ) [[1111––1144]]. HHoowwevevere,r, mmodoidfiicfaictiaotnioant aptopsiotsioitnio2n8,2n8a, mnaemlyealymaidmaitdioantioanndanesdteersitfiecraiftiicoanticoanrbcoaxrybloicxyalciicda, cleidd,tloeda dtoecaredaescereoafsietsof seiltescstievleitcytiivnidtyexin[d15e]x. [15]

Methods

Results

Conclusion