Sari Haryanti
Balai Besar Penelitian dan Pengembangan Tanaman Obat dan Obat Tradisional, Tawangmangu
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Ursolic Acid Enhances Doxorubicin Cytotoxicity on MCF-7 Cells Mediated by G2/M Arrest

Indonesian Journal of Cancer Chemoprevention Vol 3, No 3 (2012)
Publisher : Indonesian Research Gateway

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Abstract

Ursolic acid has been widely known to possess biological activity against numerous tumor cell lines. Previous studies revealed its cytotoxicity on several cancer cells  in vitro by either inducing apoptosis or cell cycle modulation. This  study was conducted to investigate ursolic  acid’s  cytotoxicity  solely  and  in  combination  with  a  chemotherapeutic  agent, doxorubicin,  on  MCF-7  breast  cancer  cells,  followed  by  observation  on  its  mechanism. Cytotoxicity of single and combinational treatment of ursolic acid and doxorubicin on MCF-7 breast cancer cells were conducted by using MTT assay. Single treatment was then evaluated by  determining  IC50  value,  while  combinational  treatment  was  evaluated  by  analyzing  cell viability  and  evaluating  combination  index  (CI).  To  explore  the  mechanism  underlying cytotoxic  effect  on  respected  cells,  further  analysis  on  cell  cycle  profile  of  single  and combinational treatment was conducted by flow cytometry. Twenty four hours treatment of ursolic  acid  inhibited  MCF-7 cells’ growth with  IC50  value  of  37  µM,  while  combinational treatment  showed  that  several  concentration  combinations  of  ursolic  acid  and  doxorubicin exhibited  synergism  of  cytotoxic  activity  on  MCF-7  cells,  giving  optimum  CI  value  of  0.54. Flow cytometric analysis showed that combinational treatment induced G2/M arrest in MCF-7  cells.  These  results  show  that  ursolic  acid  is  promising  to  be  developed  as  either  single chemopreventive  agent,  or  as doxorubicin’s co-chemotherapeutic  agent  in  breast  cancer treatment.  Observation  on  the  selectivity  as  part  of  safety  aspect  together  with  in silico,  in vitro, and in vivo study on its molecular mechanism should be conducted.Keywords: ursolic acid, doxorubicin,co-chemotherapeutic agent, breast cancer, cell cycle

Ethanolic Extract of Hedyotis corymbosa L. Increases Cytotoxic Activity of Doxorubicin on MCF-7 Breast Cancer Cell

Indonesian Journal of Biotechnology Vol 14, No 1 (2009)
Publisher : Universitas Gadjah Mada

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Abstract

Hedyotis corymbosa L. with ursolic acid as the main compound is one of the plants that has been used for traditional medicine including to cure breast cancer disease. The aim of this research is to examine the cytotoxic activity of rumput mutiara herb ethanolic extract (ERM) and its effect in combination with doxorubicin against MCF-7 breast cancer cell line as cell model of doxorubicin resistance. Hedyotis corymbosa L. herb powder extraction was done by maceration using ethanol 96% then the extract is detected for ursolic acid content. Cell viability assay of ERM, doxorubicin and  the combination of ERM and doxorubicin treatments were carried out by MTT assay to determine IC50 and CI (Combination Index). Cell cycle distribution was determined by flowcytometry. Apoptosis assay was performed by ethidum bromide-acridine orange DNA staining method. Investigation on Bcl-2 expression was determined by immunocytochemistry method. Thin Layer Chromatography of ERM had similar Rf with ursolic acid standard: 0,6. ERM and doxorubicin inhibited cell growth against MCF-7 with IC50  of 77 µg/mL and 349 nM (0,19 µg/mL) respectively. Combination of ERM and doxorubicin showed synergistic effect (CI 0.66-0.99). Combination of 25 ìg/mL ERM- 200 nM doxorubicin induced apoptosis and decreased Bcl-2 expression but showed no cell accumulation on cell cycle. Doxorubicin induced high cell accumulation in G2/M phase, but ERM at the concentration of 25 ìg/mL had a low effect in G1 phase, and ERM IC50 did not induce cell accumulation otherwise apoptosis. These results concluded that the apoptosis mechanism of combination doxorubicin-ERM is mediated by cell cycle arrest and non cell cycle arrest. Therefore ERM has a potential activity to be developed as co-chemotherapeutic agent.