title: Panaxadiol, a purified ginseng component, enhances the anti-cancer effects of 5-fluorouracil in human colorectal cancer cells.
abstract: OBJECTIVE
  Colorectal cancer is a major cause of morbidity and mortality for cancer worldwide. Although 5-fluorouracil (5-FU) is one of the most widely used chemotherapeutic agents in first-line therapy for colorectal cancer, serious side effects limit its clinical usefulness. Panaxadiol (PD) is the purified sapogenin of ginseng saponins, which exhibit anti-tumor activity. In this study, we investigated the possible synergistic anti-cancer effects of PD and 5-FU on a human colorectal cancer cell line, HCT-116.
  
  
  METHODS
  Cell viability was evaluated by an MTS cell proliferation assay. Morphological observation was performed by crystal violet cell viability staining assay. Cell cycle distribution and apoptotic effects were analyzed by flow cytometry after staining with PI/RNase or Annexin V/PI.
  
  
  RESULTS
  Cell growth was markedly suppressed in HCT-116 cells treated by 5-FU (20-100 microM) for 24 or 48 h with time-dependent effects. The significant suppression on HCT-116 cell proliferation was observed after treatment with PD (25 microM) for 24 and 48 h. Panaxadiol (25 microM) markedly (P < 0.05) enhanced the anti-proliferative effects of 5-FU (5, 10, 20 microM) on HCT-116 cells compared to single treatment of 5-FU for 24 and 48 h. Flow cytometric analysis on DNA indicated that PD and 5-FU selectively arrested cell cycle progression in the G1 phase and S phase (P < 0.01), respectively, compared to the control condition. Combination use of 5-FU with PD significantly (P < 0.001) increased cell cycle arrest in the S phase compared to that treated by 5-FU alone. The combination of 5-FU and PD significantly enhanced the percentage of apoptotic cells when compared with the corresponding cell groups treated by 5-FU alone (P < 0.001).
  
  
  CONCLUSIONS
  Panaxadiol enhanced the anti-cancer effects of 5-FU on human colorectal cancer cells through the regulation of cell cycle transition and the induction of apoptotic cells.
authors.affiliation: Department of Anesthesia & Critical Care, Tang Center for Herbal Medicine Research, University of Chicago, 5841 South Maryland Avenue, MC 4028, Chicago, IL 60637, USA.
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Li
authors.forename: Chong-Zhi
authors.initials: CZ
authors.lastname: Wang
authors.forename: Sangeeta R
authors.initials: SR
authors.lastname: Mehendale
authors.forename: Shi
authors.initials: S
authors.lastname: Sun
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.forename: Chun-Su
authors.initials: CS
authors.lastname: Yuan
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000473:pathology*; D004357:Drug Synergism; D005472:Fluorouracil / Q000494:pharmacology*; D036145:Ginsenosides / Q000494:pharmacology*; D045325:HCT116 Cells; D006801:Humans
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D036145:Ginsenosides; C004564:panaxadiol; D005472:Fluorouracil