[Knock-down of apollon gene by antisense oligodeoxynucleotide inhibits the proliferation of Lovo cells and enhances chemo-sensitivity].

In this study, the effects of apollon antisense oligodeoxynucleotide (ASODN) on the proliferation and apoptosis of human Lovo cells in vitro were investigated. Apollon ASODN was incubated with human colorectal Lovo cells for 48 h, the proliferation inhibition and the clone forming rates were detected by WST method and clone formation assay, respectively. The expression of apollon mRNA was analyzed by real time fluorescent quantitative reverse transcription polymerase chain reaction. The percentage of apoptotic cells and cell cycle distribution were determined by flow cytometry. The morphology of apoptotic cells was examined by fluorescence microscope. Lovo cells incubated with apollon ASODN combined with 5-fluorouracil (5-FU), cisplatin (DDP) or epirubicin (EPI) of different concentrations, cell proliferation inhibition rates were detected with WST method and IC50 was calculated. It was found that ASODN targeting apollon gene could all suppress the growth of Lovo cells and induce apoptosis of these cells significantly (P < 0.05). After Lovo cells treated with apollon ASODN for 48 hours, the expression of the apollon mRNA level was suppressed significantly. And a marked concentration-dependent decline of cell proliferation and clone forming, increasing of cell apoptosis levels were observed. The percentage of G0/G1 phage cells was abated and that of S phage cells was increased and the Lovo cells arrested at S phage of the cell cycle detected with flow cytometry. Many Lovo cells stained with Hoechst 33258 exhibited apoptotic morphology such as cell shrinkage, nuclear condensation and nuclear fragmentation. Cell proliferation inhibition was detected and their chemo-therapeutic effects of 5-FU, DDP and EPI on Lovo cells combined with apollon ASODN (0.08 micromol x L(-1)) were enhanced independently compared with single 5-FU, DDP and EPI groups, and the sensitivity enhanced about 2.58, 4.47, and 5.33 times respectively. It can be concluded that ASODN targeting apollon can suppress the expression of apollon mRNA, and inhibit the proliferation, induce apoptosis, arrest cell cycle at S phase of colorectal cancer Lovo cells in vitro and enhance the chemo-sensitivity to 5-FU, DDP and EPI.