Reversal of multidrug resistance in cancer cells by pyranocoumarins isolated from Radix Peucedani.
The pyranocoumarins, (+/-)-3'-angeloyl-4'-acetoxy-cis-khellactone, were isolated from Radix Peucedani, the dry root of Peucedanum praeruptorum Dunn, through bioassay-guided fractionation. The chemical structure of pyranocoumarins was determined by mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy. X-ray crystallography showed that there are eight molecules (i.e. two each of four conformers) in each unit cell with their optical activities equally cancelled out. The four conformers are 3'(R)-angeloyl-4'(R)-acetoxy-khellactone in two conformational forms, and 3'(S)-angeloyl-4'(S)-acetoxy-khellactone in two conformational forms. Pyranocoumarins caused apoptotic cell death with IC50 of 41.9+/-2.8 and 17.3+/-8.2 microM for drug-sensitive KB-3-1 and multidrug resistant (MDR) KB-V1, respectively. The two- to threefold sensitivity difference between the two cell lines is interesting considering that the same ratio for doxorubicin is 50-300. Strong synergistic interactions were demonstrated when pyranocoumarins were combined with common anti-tumor drugs including doxorubicin, paclitaxel, puromycin or vincristine in MDR KB-V1 cell line, but not in drug-sensitive KB-3-1 cells. Pyranocoumarins increased doxorubicin accumulation in KB-V1 cells by about 25% after 6 h of incubation. Pyranocoumarins treatment for 24 h down-regulated the expression of P-glycoprotein in KB-V1 cells at both protein and mRNA levels. Pyranocoumarins also transiently reduced the cellular ATP contents in KB-V1 cells in a dose-dependent manner. Our results suggest that pyranocoumarins could be a potential MDR reversing agent.
Wu
Jimmy Yiu-Cheong
JY
Department of Biology and Chemistry, Bioactive Products Research Group, City University of Hong Kong, Kowloon, Hong Kong SAR, China.
Fong
Wang-Fun
WF
Zhang
Jin-Xia
JX
Leung
Chung-Hang
CH
Kwong
Hoi-Lung
HL
Yang
Meng-Su
MS
Li
Ding
D
Cheung
Hon-Yeung
HY
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis / Q000235:genetics; D000255:Adenosine Triphosphate / Q000378:metabolism; D000970:Antineoplastic Agents / Q000494:pharmacology; D019661:Apiaceae / Q000737:chemistry*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D018360:Crystallography, X-Ray; D015536:Down-Regulation; D018432:Drug Resistance, Multiple / Q000187:drug effects*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D004357:Drug Synergism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010936:Plant Extracts / Q000494:pharmacology; D018517:Plant Roots / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry; D039681:Pyranocoumarins / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013237:Stereoisomerism
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D010936:Plant Extracts; D039681:Pyranocoumarins; D012333:RNA, Messenger; D000255:Adenosine Triphosphate