The Effects Of Macrophage Colony Stimulating Factor On Lung Cancer A549 Cell Line In Vitro

Macrophage colony stimulating factor(M-CSF, CSF-1)is first identified as a hematopoietic growth factor that stimulates proliferation, differentiation, and survival of monocytes, macrophages and their bone marrow progenitors. M-CSF is expressed by a number of cell types including monocyte macrophages, fibroblasts, endothelial cells, and endometrial epithelial cells. And M-CSF can be expressed in a variety of malignant cells, such as breast, ovarian and endometrial carcinoma. Macrophage colony stimulating factor receptor (M-CSFR, CSF-1R), which is a member of a family of tyrosine kinase receptors, is encoded by the c-fms proto oncogene. When point mutation happened in c-fms proto oncogene, M-CSFR can make normal cells disdifferentiated or malignant transformated in an autocrine, paracrine or endocrine manner. Elevated expression of M-CSFR has been seen in breast, ovarian, and uterine cancers, and the extent of expression in these tumors correlates with high grade and poor prognosis. Previous studies have showed that M-CSF not only is important in hematopoietic system,but also play a role in the occurrence and development of many cancers. The coexpression of M-CSF/M-CSFR has been found in many malignant tumors, which may show that M-CSF/M-CSFR as part of a network of autocrine or paracrine loops involve in tumor cell proliferation.Objective The purposes of the study are to observe the effects of M-CSF in lung cancer cell line A549 in vitro and to explore the possible mechaniasm.Methods The morphological changes of the cells treatmented by M-CSF were observed by using phase microscope. The inhibition of proliferation in vitro was measured by MTT assay. DNA contents were measured by flow cytometry. Cell cycles were observed at the same time after the treatment. RT-PCR technique was used to detect the change of expression of M-CSF reportor after the treatment.The main results are as follows:1. The growth of lung cancer cell line A549 was significantly inhibited by the addition of M-CSF in a concentration-dependent manner over 96h of culturing. The maximum response was obtained with 10 ng/ml of M-CSF.2. Flow cytometric analysis revealed that the treated A549 cells arrested at the G0/G1 phase of the cell cycle.3. RT-PCR showed that the mRNA expression of M-CSF reportor was reduced after the M-CSF treatment.Conclusion The exogenous addition of M-CSF has an anti-tumour activity on lung cancer cell A549 in a concentration-dependent manner.After M-CSF cultured, visible apoptotic peak does not been found, but increasing the percentage of the cells in the G0/G1.This suggests that the mechanism of the antiproliferative effect of M-CSF may involves cell cycle arrest but not inducing apoptosis.Our study show that when M-CSF inhibit the growth of A549, the mRNA expression of M-CSF reportor was reduced, which suggest the mechanism may be M-CSF interfere with the autocrine of the tumor cells.