Camptothecin-induced cell proliferation inhibition and apoptosis enhanced by DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine.
Camptothecin (CPT) reversibly binds and stabilizes cleavable complexes formed between DNA and topoisomerase I (Top1), thereby activating many downstream signaling pathways. Although several pathways induced by CPT have been elucidated, there are additional proteins that represent targets of CPT pharmacological mechanisms and remain uncharacterized. Using two-dimensional electrophoresis analysis and matrix assisted laser desorption/ionization-time of flight (MALDI-TOF)-MS/MS identification, we investigated the hepatocellular carcinoma cell line SMMC-7721 for changes of protein expression following CPT treatment. Proteomic results showed that CPT treatment caused decreased expression of galectin-1 in SMMC-7721 cells. Quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis confirmed mRNA expression changes in galectin-1. Protein expression levels of DNA methyltransferases (DNMTs) were downregulated in response to CPT. The DNMT inhibitor 5-aza-2'-deoxycytidine (DAC) sensitized SMMC-7721 cells to the cytotoxic effect of CPT. Our results indicate that inhibition of DNMT activity by CPT may play a role in CPT-induced cell proliferation inhibition and apoptosis.
Ding
Li
L
Department of Biochemical Pharmacy, School of Pharmacy, Second Military Medical University, Shanghai, China.
Qiu
Lei
L
Zhang
Junping
J
Guo
Baoyu
B
D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002166:Camptothecin / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000037:antagonists & inhibitors*; D000077209:Decitabine; D004357:Drug Synergism; D015180:Electrophoresis, Gel, Two-Dimensional; D004797:Enzyme-Linked Immunosorbent Assay; D037483:Galectin 1 / Q000037:antagonists & inhibitors; D006801:Humans; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D000972:Antineoplastic Agents, Phytogenic; D037483:Galectin 1; C445499:LGALS1 protein, human; D000077209:Decitabine; D004248:DNA (Cytosine-5-)-Methyltransferases; D001374:Azacitidine; D002166:Camptothecin