Effect Of Nordy On Growth Of Human Pulmonary Adenocarcinoma Cell Line A549 And Its Mechanism

Lung cancer is one of the most common malignant tumours. In recent years,although multiple therapeutical measures have been taken, its five-year survival rate is only ten to thirteen percent.For this reason,it is important to research and develop new methods for treatment of lung cancer. Among the new strategies for cancer therapy, differentiation therapy has been widely studied in recent decades. Our previous studies have showed that nordihydroguaiaretic acid(NDGA) could inhibite growth of glioma in vivo and in vitro,but its effect on lung cancer is unknown.Nordy is a newly synthetized compound in our laboratory based on the structure of NDGA and its anti-tumour effects in vitro and in vivo are under study.In this study, flow cytometry, MTT technique, light and electron microscopy, immunohistochemistry were used to explore anti-tumour effect of Nordy on the growth of human pulmonary adenocarcinoma cell line A549.The aim of the study was to provide experimental evidence for the possibility of clinical trails of Nordy for lung cancer therapy.The main results and conclusions are as follows:1. A549 cells were treated with 100μmol/L of Nordy at different time points (12h,24h,48h,72h).It was showed that the differentiation effect induced by Nordy.Under light microscope, cellular atypia was reduced, cellular processes increased,mitotic figures decreased and mitotic index reduced.Under electron microscope, the nuclei became regular and nucleoli became smaller.Moreover, mitochondrial crista were breaken and mitochondria became swellen and myelin figure could be identified. Degranulation rough endoplasmic reticulum could also be found. These results suggested that Nordy could inhibit growth of A549 cells and induce differentiation of this cell line.2. After A549 cells being treated with various concentration(50μmol/L,100μmol/L,200μmol/L) of Nordy,compared with control group ,the proliferation rates were decreased obviously.With increasing concentration and longer time of treatment, cell numbers were reduced significantly in a dose- and time-dpendent pattern.The average IC50 value was 62.5μmol/L.3. Cell cycle analysis and apoptosis delection showed that cell number in G0/G1 phases was increased while that in S and G2/M phases was decreased after treatment with100μmol/L Nordy for 12,24and 48 hours,along with the increase of apoptosis rate .Allthese results suggested that the growth of A549 cells was blocked in G1→S phases and cell apoptosis was induced by Nordy.4. Immunohistochemistry revealed that expression levels of PCNA, bcl-2 and vimentin were reduced in A549 cells after treatment with 100μmol/L of Nordy for12,24,48hours. These results showed that down-regulation of PCNA,bcl-2 and vimentin might be the possible mechanism of the inhibiting effect of Nordy on growth of A549 cells.These experimental results showed that the effect of Nordy on human pulmonary adenocarcinoma cell line A549 in vitro was similar to that of NDGA extracted from plants.This study could provide experimental data for its development and further investigation for the treatment of human lung cancer.