Quantitative monitoring and mutations of ctDNA before and after non-small cell lung cancer radical surgery

Objective The aim of this study was to study the quantitative expression of circulating tumour DNA(ctDNA) in patients with non-small cell lung cancer(NSCLC) before and after radical operation and to explore the correlation between gene mutations in non-small cell lung cancer tissues and those in ctDNA.Methods We randomly assigned 5 NSCLC patients from the Department of Thoracic Surgery of Fujian Medical University Union Hospital. All the patients had undergone radical surgery. Venous blood samples were collected from the 5 NSCLC patients at two time points(before the operation and 21–37 days after the operation) for monitoring ctDNA levels. This was done by isolating plasma from venous blood using high velocity centrifugation, extracting DNA from the plasma using the QIAamp Circulating Nucleic Acid kit, and then quantifying the ctDNA levels. The results were analyzed using the Wilcoxon Rank Sum Test. Moreover, the ctDNA levels were compared with those of carcinoembryonic antigen(CEA), which was detected simultaneously with the ctDNA. Then, DNA samples from the tumor tissues and peripheral blood cells and ctDNA were sequenced using the Hiseq2000 sequencing platform(Illumina) and the mutant genes were screened out. Mutations that occurred within the tumor tissues were used as positive control, whereas those found in the pre-operative blood cells were used as a negative control. Based on the mutational analysis of ctDNA genes, a total of 508 cancer-related genes were screened. Results The median values of the pre-and post-operative ctDNA levels in the 5 patients with NSCLC were 0.612(0.518–0.876) and 0.430(0.372–0.612) ng/μL, respectively. There was a significant difference between the two groups(P < 0.05). The pre-operative CEA level was slightly higher than the post-operative level(P > 0.05). In one of the cases, LC tissues showed multiple mutations, consistent with pre-operative ctDNA. Moreover, isogenic mutations of the same type were not detected in post-operative ctDNA or peripheral blood cells. Conclusion Mutations found in the lung cancer(LC) ctDNA gene were consistent with the mutation type of LC tissue. Hence, the quantitative and qualitative analysis of ctDNA is a promising novel molecular biomarker for the evaluation of tumor burden changes in NSCLC.

Interleukin-18 Suppresses Angiogenesis and Lymphangiogenesis in Implanted Lewis Lung Cancer

Objective： To investigate the effects of interleukin-18 （IL-18） on implanted Lewis lung cancer in suppressing angiogenesis and lymphangiogenesis. Methods： One week after hypodermic inoculation of Lewis cells, sixteen tumor-bearing syngeneic mice were randomly divided into two groups. The mice in the treatment group （group A） were intraperitoneally injected with the IL-18 and in the control group （group B） were intraperitoneally injected with normal saline for 7 days. The mice were killed on day 19. The morphology of the tumors was studied, the growth curve was described and the tumor inhibition rate was calculated. The numbers of metastasized pulmonary colonies were calculated using hematoxylin-eosin （HE） staining. The vascular endothelial growth factor A （VEGF-A）, vascular endothelial growth factor C （VEGF-C）, microvessel density （MVD） and lymphatic microvessel density （LMVD） in tumor mass were measured by immunohistochemistry staining （IHCS）. Results： In the group A, the tumor volume, tumor weigh, lung metastatic nodules, expression of VEGF-A and VEGF-C, MVD were all decreased significantly （P0.01 or P0.05）. The tumor inhibition rate was 75% and the inhibition rate of lung metastatic nodules was 61%. The LMVD in group A was also lower than group B, but without significant difference （P0.05）. Conclusion： IL-18 could suppress the tumor growth and metastasis of implanted Lewis lung cancer by way of down-regulating VEGF-A and VEGF-C expression, suppressing angiogenesis and lymphangiogenesis.

白细胞介素-18抑制Lewis肺癌小鼠移植瘤生长与诱导移植瘤细胞凋亡的研究(英文)

Objective:The aim of our study was to investigate the effects of interleukin-18(IL-18) on implanted Lewis lung cancer in suppressing tumor growth and inducing tumor cells apoptosis.Methods:One week after hypodermic inoculation of Lewis cells, sixteen tumor-bearing syngeneic mice were randomly divided into two groups.The mice in the treatment group were intraperitoneal injected with the IL-18, in the control group were intraperitoneal injected with normal saline.The health conditions of the mice were measured, the morphology of the tumors was studied and the apoptosis of implanted lung cancer cells was detected by TUNEL to evaluated the effects of IL-18.Results:IL-18 had no significant effects on the health conditions of the mice, but it could suppress the implanted tumor growth(inhibition rate was 75%) and induce tumor cells apoptosis.Conclusion:IL-18 can suppress the implanted Lewis lung cancer cells by way of inducing tumor cells apoptosis.It could be used as a new strategy for lung cancer.