The Effect Of SCD40L Combined With Vinorelbine On Lung Adenocarcinoma Cell In Vitro

Background: Lung cancer remains the leading cause of cancer- related deaths in the wor1d and its incidence rate has been increasing significant1y in the last two decades in China. Unfortunately, the overall survival for lung cancer with conventional treatments (chemotherapy, radiotherapy, and surgery) is less than 15% in the world. In the past few years, follow the continuously studying of molecule-biology, biomolecule target treatment has been a significant means of the lung cancer treated.The cell surface molecule CD40 is a member of the tumor necrosis factor receptor superfamily and is broadly expressed by immune, hematopoietic, vascular, epithelial, and a wide range of tumor cells, including lung cancer cells. CD40 ligand (CD40L), also known as CD154, is the chief ligand described for CD40. CD40 and CD40L play a key role in intercellular interactions of the cells of immune system. As a potential target for novel cancer therapy, CD40 may mediate tumor regression through both an indirect effect of immune activation and a direct cytotoxic effect on the tumor. Several drug formulations that target the CD40 pathway have undergone clinical evaluation in advanced-stage cancer patients, and initial findings show objective clinical responses and immune modulation in the absence of major toxicity.Recently, some studies have shown that the CD40/CD40L interaction may make influence on the sensitivity of tumor cells to chemotherapy. Drug resistance is one of the main causes of failure in lung cancer treatments, and is an unsolved issue in the worldwide. So the CD40 signal may represent a new pathway in this issue. However, published data on the effect of CD40 signal on cancer cells sensitivity to chemotherapy are inconclusive. The aim of this study is to investigate the effect of sCD40L combined with Vinorelbine on lung adenocarcinoma cell line A549.Objective: (1) To investigate the effect of sCD40L combined with vinorelbine on lung adenocarcinoma cell line A549, and to known explore if stimulation of CD40 can upregulate lung adenocarcinoma cell line A549 sensitivity to vinorelbine ; (2) To study the possible mechanism under the effect of sCD40L combined with vinorelbine on A549, if which dues to apoptosis and/or cell cycle associated way; (3) To evaluate the changes of Caspase-3 activity before and after sCD40L was added to vinorelbine, and to understand if the traditional Caspase-3 path was a necessity for the effect of sCD40L.Methods: Lung cancer A549 cells were chosen as target cells and CD40 signal was stimulated by soluble CD40 ligand ( sCD40L). MTT assay and flow cytometry were employed to determine the changes of cell proliferation inhibition﹑cell cycle and apoptosis of A549 cells treated by vinorelbine after CD40 was stimulated. The activity of Caspase-3 was measured using caspase-3 cellular activity assay kit plus.Results: (1) After pretreated with sCD40L, the inhibition rate of vinorelbine on A540 cells was 22.18±9.45%, significantly higher than 16.94±10.63% of the vinorelbine alone (P < 0. 05); the observation by microscope also confirmed the best inhibition effect in the group of sCD40L combined with vinorelbine. (2) About the cell cycles, the rate of cells with phases S+G2 was 7.25±1.34% for combination group, not substancially different from 8.71±0.93% of the vinorelbine alone (P>0. 05). (3) The rate of apoptosis in group of combination was 14.91±3.48%, not substancially different from 12.50±2.30% of the vinorelbine alone (P>0. 05). (4) No obvious changes for the activity of Caspase-3 were observed when sCD40L was used alone. This result (OD values) was 0.059±0.002 for combination group, significantly decreased when comparied with 0.098±0.002 of vinorelbine only (P < 0. 05).Conclusions: (1) Stimulation of CD40 can upregulate lung adenocarcinoma cell line A549 sensitivity to Vinorelbine; (2) The mechanism may be not associated with pro-apoptosis and/or the inhibition of cell cycles; (3) The effect of sCD40L may be independent of the classical caspase-3 path.