BACKGROUNDIn recent years, many progresses have been made in molecular target therapy for lung cancer, in which anti-angiogenic target therapy is a hot spot drawing researchers' attention. The aim of this study is to explore the expression of canstatin gene transfected into human lymphocytes and its inhibitory effect on growth and metastasis of Lewis lung carcinoma.

METHODSThe eukaryotic expression vector of pCMV-Script and the recombinant pCMV-Script/Canstatin vector were separately transfected into lymphocytes by electroporation. The expression of canstatin protein in supernatant of lymphocyues was examined by SDS-PAGE assay. Furthermore, Lewis lung carcinoma cells were subcutaneously inoculated to C57BL mice to make animal model of tumor. When the transplanted tumors on the mice developed to 1cm³, the 30 mice were randomized into 3 groups, which were injected with 0.2mL supernatant of lymphocytes transfected with recombinant vector or naked vector, or 0.2mL NS respectively. After the treatment for 14 days, the size and pathological section of subcutaneous tumors were observed, and the number of pulmonary metastatic node was calculated.

RESULTSCanstatin protein was found in supernatant of the lymphocytes in the recombinant vector group by SDS-PAGE assay. After the treatment, the tumor size in the recombinant vector group (1.49cm³±0.18cm³) was significantly smaller than that in the naked vector group (2.44cm³± 0.19cm³) and NS group (2.53cm³±0.18cm³) (P=0.000). The numbers of pulmonary metastatic node were 3.40±1.14, 7.60±2.61 and 7.60±2.41 in the recombinant vector group, naked vector group and NS group respectively (recombinant vector group vs the other two groups, P=0.013).

CONCLUSIONSThe pCMV-Script/Canstatin vector can express canstatin protein in human lymphocytes. Canstatin has strongly inhibitory effect on growth and metastasis of mouse Lewis lung carcinoma.

BACKGROUNDThe methylation of tumor suppressor genes is believed to be one of the most important mechanisms of oncogenesis. In order to research the malignant transformed mechanism induced by radiation, the abnormal promoter methylation of p14(ARF) , p16(INK4a) and BUB3 genes are detected in the transformed human bronchial epithelial cells (BEP2D) induced by α-particles.

METHODSAbnormal promoter methylations were detected with methylation specific PCR (MSP). The level of p14 ARF gene transcription was analyzed by using RT-PCR. DNA was purified and transformed and sequenced.

RESULTSp14(ARF) gene was not methylated in BEP2D cells, but was methylated in the malignant transformed BERP35T-1 cells, and the level of its transcription was depressed remarkably in the latter. However p16(INK4a) gene, which shares two exons with p14 (ARF) gene, was not methylated. BUB3 gene was not methylated in BEP2D as well as BERP35T-1 cells and this was further proved by sequencing analysis.

CONCLUSIONSThe methylation of two tumor suppressor genes (p14(ARF) and p16(INK4a)) that share two exons and controll cell cycle are not synchronous in the transformed human bronchial epithelial cells induced by α-particles, and the methylated one (p14(ARF)) is repressed in transcription. The gene of mitosis spindle check-point (BUB3) is unmethylated.

BACKGROUNDIt has been proved that hyaluronan was involved in adhesion and invasion behavior of varied tumor cells. Layilin is a receptor of hyaluronan found recently and has close relationship with cytoskeleton. The aim of this study is to investigate the effect of short hairpin RNA (shRNA) targeting layilin on adhesion and invasion behavior of human lung adenocarcinoma cell line A549 induced by hyaluronan in vitro.

METHODSRNA interference plasmid that included U6 promoter and could express shRNA targeting layilin was designed, constructed, and transfected into A549 cell line. Layilin expression was examined by RT-PCR, Western blot and immunofluorescence. Adhesive and invasive ability was examined by plate adhesion model and Boyden chamber model.

RESULTSAfter plasmid transfected, layilin expression in A549 cells obviously decreased (P < 0.01), and the numbers of adhesive A549 cells on plate and A549 cells permeating septum of Boyden chamber induced by hyaluronan also significantly decreased (P < 0.01).

CONCLUSIONSThe shRNA targeting layilin can efficiently inhibit the adhesive and invasive ability of A549 cells induced by hyaluronan in vitro.

BACKGROUNDIt was reported that tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) was a powerful pulmonary carcinogen, predominantly inducing adenocarcinoma of the lung in mouse. The aim of this study is to assay metabolites of NNK, which are 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its O-glucuronide (NNAL-Gluc), and their ratio (NNAL-Gluc/NNAL) in smokers and non-smokers' urine, and to explore the carcinogenicity of NNK among different people.

METHODSUsing high pressure liquid chromatograph (HPLC) and gas chromatograph-mass tadom (GC-MS/MS), NNAL-Gluc and NNAL in 24h urine were detected in 8 healthy smokers, 10 lung cancer smokers and 4 healthy non-smokers.

RESULTSBoth of the two metabolites were not found in non-smokers' urine. The ratios of urine NNAL-Gluc/NNAL were greatly different among different smokers. The mean ratio of NNAL-Gluc/NNAL in healthy smokers was 4.95, and 0.5 in lung cancer smokers.

CONCLUSIONSThe results provide the first evidence for metabolite detection of tobacco-specific nitrosamine in Chinese smokers' urine . The result suggests that detoxification ability of healthy smokers is higher than that of lung cancer smokers. It may provide a detective way to screen high risk people for lung cancer in smokers.

BACKGROUNDLung cancer cell lines A549 and NCI-H446 with different radiosensitivity to ionizing radiation (IR) have different MDM2 gene expression status, which may contribute to the radioresistance of cells. The aim of this study is to use small interfering RNA (siRNA) targeting MDM2 to investigate the influence of MDM2 gene silencing on radioresponse of A549 cell.

METHODSPlasmid targeting MDM2 was constructed with pPUR/U6 vector and oligonucleotide designed according to the sequence of effective antisense oligonucleotides and principles of siRNA design. A549 cells were transfected by Lipofectamine™ 2000. MDM2 expression in A549 cells was detected by RT-PCR and Western blot. Radiation-mediated cell killing was detected by flow cytometry.

RESULTSTwo out of three siRNA plasmids were constructed successfully. siRNA transfection resulted in downregulaton of MDM2 expression of A549 cells on mRNA and protein levels. After treated with siRNA, radiation-mediated cell killing of A549 cells was significantly increased (P < 0.01).

CONCLUSIONSThe results support the hypothesis that MDM2 gene is a candidate for radioresistance in A549 cells. siRNA targeting to MDM2 can enhance the radiation-mediated cell killing of A549 cells.

BACKGROUNDLung cancer is the leading cancer of malignant tumor in China.It is the direction that poeple make efforts to seek gene therapy of lung cancer. The aim of this study is to explore the effects of transfected growth arrest-specific homeobox gene (Gax gene) on the proliferation and expressions of c-fos and c-jun mRNA in A549 cells.

METHODSA549 cells were transfected with Gax gene by adenovirus. Expressions of Gax mRNA and protein were detected by RT-PCR and immunocytochemistry. The expressions of c-fos and c-jun mRNA were evaluated by RT-PCR. The proliferation inhibition effect of Gax transfection on A549 cells was evaluated by MTT assay.

RESULTSOnly in the A549 cells transfected with Gax gene the Gax expression was confirmed by RT-PCR and immunocytochemistry. Compared with that in the control group, c-fos and c-jun mRNA level decreased significantly in Gax-transfected A549 cells (t=7.755, P < 0.01; t= 5.938 , P < 0.01). MTT assay showed that the proliferation inhibition rates of A549 cells transfected by Ad-Gax for 24h, 48h and 72h were (47.35±5.36)%, (54.96±1.78)%, and (65.39±5.11)% respectively. And these proliferation inhibition rates were significantly higher than those in the control group (Chi-Square=7.152, 9.431 and 12.847, P < 0.01).

CONCLUSIONSGax gene can inhibit the proliferation of A549 cells. Its molecular mechanism may be through down-regulating the expressions of c-fos and c-jun.

BACKGROUNDVascular endothelial growth factor (VEGF) is known to be one of the most important factors for angiogenesis and tumor cell infiltration. The aim of this study is to determine the influence of phosphorothioate-moeified antisense VEGF oligodeoxynucleotides (ASODN) formulated in cationic liposome on microvessel density (MVD) and VEGF expression of lung cancer.

METHODSLewis lung carcin- oma model was established by subcutaneous injection of Lewis lung carcinoma cells into 40 C57BL/6 mice. Within 24h after inoculation, mice were randomly assigned to four groups treated with ASODN, sense oligodeoxynucleotides (SODN), mismatch oligodeoxynucleotides (MODN), or liposome alone respectively, twice a week for 4 weeks. The weight and volume of subcutaneous tumors were measured. The morphological and ultrastructural changes of tumor cells were observed under microscope and electron microscope. MVD and expression of VEGF protein and VEGF mRNA were detected by immunohistochemical staining and RT-PCR.

RESULTSThe tumor weight in the control group was (7.83±0.78)g, and (4.49±0.43)g in the ASODN group (P < 0.01). The inhibition rate of tumor growth in the ASODN, SODN and MODN groups was 42.6%, 5.1% and 3.2% respectively. MVD and expression of VEGF protein and VEGF mRNA were decreased markedly in the ASODN group compared to the other three groups (P < 0.01).

CONCLUSIONSThe results demonstrate that MVD and VEGF expression of lung cancer can be inhibited by VEGF ASODN injected into tumor tissue in C57BL/6 mice.

BACKGROUNDWith the improvement of instrument and operative technique, video-assisted thoracoscopy is more and more widely used. The aim of this study is to summarize and discuss the results of video-assisted thoracoscopic surgery (VATS) in 76 patients with thoracic tumors.

METHODSThe data of 76 cases were analyzed retrospectively. From July 1997 to June 2004, 76 patients (46 men and 30 women) with thoracic tumors underwent VATS for peripheral pulmonary nodules (52), leiomyoma of esophagus (10), mediastinal lymphadenectasis (6), malignant pleural fluid (5), bronchogenic cyst (1), mediastinal cyst (1), neurofibroma (1).

RESULTSAll procedures were performed successfully under VATS except for 8 cases, who were converted to thoracotomy for lung cancer. There was no mortality or severe complication in this series.

CONCLUSIONSVATS is a safe and effective technique in selected patients with thoracic lesions. The overall incidence of perioperative complication is low. VATS has obvious advantages in treatment of benign thoracic lesions, however, the indications should be selected carefully for malignant tumors.

BACKGROUNDSome of the locally advanced non-small cell lung cancer (NSCLC) need different trachea-bronchoplasty operative styles in order to make the widest possible to resect the tumor and remain normal pulmonary function. The aim of this study is to explore the surgical problem during trachea-bronchoplasty operation.

METHODSThere were 2206 patients with NSCLC underwent surgical treatment from January 2003 to June 2005 in this hospital. Of the 2206 cases, 100 patients accepted the trachea-bronchoplasty, whose clinic data were analyzed. There were 42 cases of squamous cell carcinoma, 23 adenosquamous carcinoma, 11 adenocarcinoma, 5 mucoepidermoid carcinoma, 4 adeoid cystic carcinoma, 3 carcinoid and 12 undetermined. Thirty-four cases were in stage IB, 23 in stage IIB, 23 in stage IIIA and 20 in stage IIIB. There were 42 cases of right upper sleeve lobectomy, 1 right lower sleeve lobectomy, 24 left upper sleeve lobectomy, 4 left lower sleeve lobectomy, 8 sleeve bilobectomy, 17 carinal reconstruction, 4 sleeve lobectomy plus pulmonary artery angioplasty.

RESULTSComplete resection (R0) of the cancer was performed in 97 patients and uncomplete resection (margin positive, R1) was performed in 3 patients. Postoperative complication happened in 5 cases (the occurrence rate was 5%): Pneumonia in 2 cases, pleura cavity infection in 1 case, broncho-pleura fistula in 1 case, alveoli-pleura fistula in 1 case. One patient died of pulmonary infection, the operative mortality was 1%. The postoperative inpatient time was from 4 days to 27 days, with median of 11 days.

CONCLUSIONSTrachea-bronchoplasty is suitable for some patients of the locally advanced NSCLC and consistent to the tumor surgical treatment principle. A satisfactory cure effect can be obtained for undergoing such operative style. The key point of successful operation is the operating skill to manage trachea, bronchi and pulmonary vessels.

BACKGROUNDThere are lots of mucus, blood, inflammatory cells and necrotic material in the pick-and-smear slides, resulting in a low detection rate. Liquid-based cytologic test (LCT) has been applied for cervical cytology diagnosis successfully and widely, however it is few reported yet for sputum cytology diagnosis at present. The aim of this study is to evaluate the clinical value of LCT in sputum examination of patients with lung cancer, and to find a novel method of early diagnosis of lung cancer.

METHODSThe cytologic findings and the diagnostic rate for lung cancer were compared between LCT and conventional pick-and-smear method.

RESULTSThere were smaller area of smear membrane, clearer background, more distinctly cytologic picture and stereoscopic fell by LCT comparing with pick-and-smear method. The diagnostic rate for small cell lung cancer by LCT was significantly higher than that by pick-and-smear method (P < 0.05). After combined detection of the two methods, the diagnostic rate for lung cancer was obviously improved (85.1%), which was remarkably higher than that by pick-and-smear method alone (P < 0.01).

CONCLUSIONSIt is operated easily for LCT to be well controlled in making smear and dyeing. LCT may be a novel technique worthy of wide use. Combination of LCT with pick-and-smear method appears to be of great value in clinical application.