BACKGROUNDTo investigate gene diagnosis of micrometastasis in lymph nodes in patients with non-small cell lung cancer (NSCLC) and the feasibility of mucin 1 (MUC1) mRNA and cytokeratin 19 (CK19) mRNA as molecular marker to detect micrometastasis of lung cancer.

METHODSExpression of MUC1 mRNA and CK19 mRNA was detected in 119 lymph nodes taken from 31 patients with NSCLC, 35 lymph nodes from 10 patients with pulmonary benign diseases as controls by nested reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTSIn the 119 lymph nodes from lung cancer patients, CK19 mRNA expression was detected in 66 lymph nodes (55.5%) and MUC1 mRNA expression was detected in 65 lymph nodes (54.5%) by RT-PCR. Neither CK19 mRNA nor MUC1 mRNA expression was observed in all the 35 lymph nodes in the benign pulmonary lesion group.

CONCLUSIONSThe results suggest that the detection of both MUC1 and CK19 mRNA might be helpful to diagnose NSCLC micrometastasis in lymph nodes. The establishment of this method may lead to an earlier diagnosis of metastasis for lung cancer.

BACKGROUNDThe human FHIT gene at chromosome 3p14.2 is a tumor suppressor gene, and its abnormality in structure and function is related to carcinogenesis and progression of lung cancer. It is postulated that FHIT and NIT1 likewise collaborate in biochemical or cellular pathway in mammalian cells, but their molecular mechanisms in lung cancer cell are still unknown. The aim of this study is to construct procaryotic expression vector of human NIT1, providing a foundation to explore the expression of human NIT1 protein and to study the interaction of NIT1 and FHIT genes in lung cancer cell lines.

METHODSThe NIT1 cDNA was acquired by RT-PCR. EcoRI/NotI digested PCR product was directly cloned into procaryotic expression vector pET-32a.

RESULTSThe sequence of NIT1 cDNA clone exactly corresponded with the sequence of NIT1 cDNA in GenBank. The expectant fragments of DNA were obtained after recombinant procaryotic expression vector was digested by EcoRI and NotI.

CONCLUSIONSThe procaryotic expression vector of human NIT1 is successfully constructed by RT-PCR and direct clone. It provides an important basis to detect the expression of NIT1 protein and to further explore the relationship between NIT1 and FHIT genes in oncogenesis and development of human lung cancer.

BACKGROUNDIt has been proved that Tanshinone has obvious anticancer effect, but its mechanisms of anticancer are still unknown. Anticancer Ketonon is complex antitumor drug which Tanshinone is combined with other anticancer elements. This study aims to explore the antineoplastic effects of Anticancer Ketonon on Lewis lung cancer and the mechanisms in mice.

METHODSThe mice were divided into three groups: Ketonon group, 5-fluorouracil (5-Fu) group and control group. The former two groups were treated with responsive drugs after subcutaneous inoculation of Lewis lung cancer. The last group was only treated with normal saline after inoculation. Apoptosis index and cell cycle were measured by flow cytometry.

RESULTSTwo experiments were carried out in male and female mice respectively. The tumor inhibitory rates of Anticancer Ketonon were 38.9% and 32.2% respectively, those of 5-FU were 59.6% and 53.9%. Compared with those of control groups, the tumor weights in Ketonon group and 5-Fu group were statistically decreased (P < 0.05). Metastasis rates of the lung in the three groups were not statistically different (P > 0.05). The apoptosis index of Ketonon group was significantly higher than that of control group (P < 0.05), but the cell cycle was not statistically changed compared with that of control group (P > 0.05).

CONCLUSIONSAnticancer Ketonon has antineoplastic effect on Lewis lung cancer in mice and the mechanism may be associated with inducing apoptosis of tumor cells.

BACKGROUNDLung cancer is the leading cause of malignant tumor death among Chinese population. It has been known that the development of lung cancer may be associated with genetic po-lymorphism of some lung cancer related genes. The aim of this study is to evaluate the relationship between genetic polymorphism of metabolizing enzymes and susceptibility of lung cancer in Chinese population.

METHODSPolymorphism of CYP2E1 RsaI/PstI and GSTM1 was detected in 99 patients with lung cancer and 66 patients with benign pulmonary disease by PCR-RFLP and PCR. The association between genetic polymorphism and susceptibility of lung cancer was analyzed.

RESULTSNo significant difference in three RsaI/PstI genotype distribution of CYP2E1 was found between lung cancer group and control group (Chi-Square=1.374, P=0.241). (2) The frequency of GSTM1-null genotype in lung cancer group was significantly higher than that in control group (57.6% vs 40.9%, Chi-Square=4.401, P=0.036). (3) The individuals who carried with GSTM1-null genotype had a 1.96 fold increased risk of lung cancer (OR=1.96, 95%CI=1.042-3.689, P=0.037) than those who carried with GSTM1-present genotype. (4) When data were stratified by smoking status, the smokers who carried with c1/c1 genotype had a significantly higher risk of lung cancer (OR=3.525, 95%CI=1.168- 10.638, P=0.025) than those never-smokers who carried with at least one c2 allel. (5) When combination of polymorphism of CYP2E1 RsaI/PstI genotype and GSTM1 genotype was analyzed, compared with individuals who had concurrent present of GSTM1 and at least one c2 allel genotype, the risk of lung cancer for combination of GSTM1 null and c1/c1 genotype was increased significantly (OR=3.449, 95%CI=1.001- 11.886, P=0.050). Considering smoking status, compared with never-smokers who had concurrent present of GSTM1 and at least one c2 allel genotype, the risk of lung cancer for combination of GSTM1 null and c1/c1 genotype was remarkably increased (OR=11.553, 95%CI=1.068-124.944, P=0.044), as well as that for combination of GSTM1 null and at least one c2 allel genotype (OR=13.374, 95%CI=1.258-142.166, P= 0.032).

CONCLUSIONS(1)GSTM1 null genotype is an important factor associated with increased risk of lung cancer. (2) The combination of c1/c1 and GSTM1-null genotype can remarkably increase risk of lung cancer both in smokers and non-smokers.

BACKGROUNDMetastasis is not only the malignant characteristics of lung can- cer, but also the chief cause of failure to cure and high mortality of lung cancer. To better explore and understand the mechanism of lung cancer metastasis and to search for potential markers for early diagnosing and reversing lung cancer metastasis, differential proteomic analysis is conducted in two human large cell lung cancer cell lines with high metastasis potentials (L9981) and low metastasis potentials (NL9980) by two-dimension gel electrophoresis (2-DE).

METHODSThe total proteins of the two cell lines were separated by immobilized pH gradient (IPG)-based 2-DE. The differentially expressed proteins of the two cell lines were analyzed using image analysis software.

RESULTSA high resolution and reproducible 2-DE image was successfully obtained. Average deviations for protein position in IEF direction were (0.858±0.076)mm and (1.514±0.127)mm in SDS-PAGE direction. The relative standard deviation for protein volume was (12.06±0.580)% in L9981 and (12.22±0.640)% in NL9980. The average total number of protein spots was 902±169 in L9981 cells and 941±173 in NL9980 cells in three repeated experiments. Image analysis of siliver-stained 2-DE image revealed that 4 protein spots had significant differential expressions in L9981 and NL9980 (student's t-test, P < 0.05). Fifteen protein spots were only detected in L9981, and 27 protein spots were only detected in NL9980.

CONCLUSIONSThe results in this study suggest that an obviously differential proteomic expression exists between the human high- and low-metastatic large cell lung cancer cell lines. It will be helpful to further understand the molecular mechanisms of lung cancer invasion and metastasis, and provide new experimental evidence for searching metastatic-related molecule of lung cancer.

BACKGROUNDTo clone DNA sequence of human telomerase reverse transcriptase (hTERT) promoter, and study its transcriptional activities in various human lung cancer cells and normal lung cell.

METHODShTERT promoter of 1.1 kb was amplified with polymerase chain reaction (PCR) method, utilizing DNA of 293 cell as template. After DNA sequencing with correct result, the hTERT promoter was inserted into luci-ferase reporter vectors (pGL3-Basic) to reconstruct a recombinant plasmid named pGL3-hTERTp. Then the reconstructed plasmid was transiently transfected into lung cancer cell lines A549, SPC-A-1, LTEPa-2, NCI-H446, YTMLC, GLC-82, A2 and human embryonic pulmonary fibroblast cell line MRC-5. The transcriptional activities of hTERT promoter in various cells were determined by measuring the luciferase activities after 48 hours of transfection.

RESULTSElectrophoresis demonstrated that cloned hTERT promoter was about 1.1 kb, and DNA sequencing showed a same sequence as registered in GenBank. The cloned hTERT promoter was located between 1 126 bp and 43 bp in upstream of the transcription start site ATG and the length was 1 086 bp. The recombinant plasmid pGL3-hTERTp was confirmed by double digestion and PCR method with correct results. Luciferase assay showed there were different transcriptional activities of hTERTp in various lung cancer cell lines, but not in the MRC-5 cell line.

CONCLUSIONSThe hTERT promoter cloned in this study has transcriptional activities in various lung cancer cell lines but not in normal cell. It may act as control element in tumor-targeting gene therapy with hTERT.

BACKGROUNDTo explore the effects of transfection of nm23-H1 gene on expression of β-catenin and phospho-β-catenin in human high-metastatic large cell lung cancer line L9981, and to provide evidence to elucidate the molecular mechanism of nm23-H1 mediated tumor metastatic suppression.

METHODSTo determine whether nm23-H1 contributes to cytoplasm and nuclear β-catenin and phospho-β-catenin expression, the expression level of β-catenin and phospho-β-catenin in cytoplasm and nucleus was detected in human high-metastatic large cell lung carcinoma cell lines including primary cell line L9981 with nm23-H1 gene deletion, L9981-nm23-H1 transfected with nm23-H1 gene, and L9981-pLXSN transfected with vector by Western blot.

RESULTS(1)β-catenin expression in L9981-nm23-H1 cytoplasm (IOD) (3 649±118) was significantly higher than that in L9981 (1 401±31) and L9981-pLXSN (1 350±55) cell lines (P < 0.001);(2)There was no statistical diffe-rence of the β-catenin expression in nucleus among L9981-nm23-H1 (2 945±68), L9981 (2 604±23) and L9981-pLXSN (2 652±53) cell lines (P > 0.05);(3)Phospho-β-cetenin expression of cytoplasm in L9981-nm23-H1 cell line (3 123±102) was significantly lower than that in L9981 (4 362±131) and L9981-pLXSN ( 4 500 ±117) cell lines (P < 0.001);(4)Phospho-β-catenin expression of nucleus in L9981-nm23-H1 (5 136±112) was significantly higher than that in L9981 (2 666±116) and L9981-pLXSN (2 661±66) cell lines (P < 0.001);(5)There was no statistical difference of β-catenin or phospho-β-catenin expression in cytoplasm and nucleus between L9981 and L9981-pLXSN cell lines (P > 0.05).

CONCLUSIONS(1)nm23-H1 gene transfection can remarkably upregulates the expression of cytoplasm β-catenin in human high-metastatic large cell lung cancer cell line L9981, but do not induce the nucleus accumulation of β-catenin; (2)Transfection of nm23-H1 gene can significantly upregulate the expression of phospho-β-catenin in nucleus and remarkably downregulate the expression of phospho-β-catenin in cytoplasm of L9981; (3)Regulation of the expression of the key modecule, β-catenin, in Wnt signal pathway might be the important melecular mechanisms which nm23-H1 gene controls "Lung Cancer Metastatic Suppresive Cascade" and reverves cancer metastasis in L9981.

nm23-H1 is a proven tumor metastasis suppressive gene, tumor metastasis phenotype could be reversed by transfected nm23-H1 cDNA. This study was conducted to transfect nm23-H1 cDNA into L9981 cells and to explore the function of nm23-H1 in reversing the malignant phenotype of L9981 cells. The plasmid of pLXSN-nm23-H1-EGFP was constructed by gene clone technique, and the transfected nm23-H1 cDNA cell lines of L9981-nm23-H1 was established. The protein expression of nm23-H1 was detected by Western blot. The biologic features of L9981-nm23-H1 cells were studied in vitro and in vivo. The results showed that the fusion protein of nm23-H1-EGFP was stable, continuous and expressed with high efficiency in L9981-nm23-H1 cells. The cell proliferation, colon formation and invasive ability are significantly lowered in L9981 cells transfected nm23-H1 cDNA (P < 0.01); the tumorgenesis and the lung metastasis incidence was lower in tranfected nm23-H1 cells than in L9981 and L9981-Plxsn in nude mice (P < 0.01); the rate for inhibiting tumorgenesis of nm23 -H1 was 82.56%. These data suggest that the malignant phenotype could be reversed by wild nm23-H1 gene in L9981 cells.
Animals ; Cell Line, Tumor ; Cell Proliferation ; Humans ; Lung Neoplasms ; pathology ; Mice ; Mice, Nude ; NM23 Nucleoside Diphosphate Kinases ; genetics ; Neoplasm Metastasis ; Neoplasm Transplantation ; Recombinant Fusion Proteins ; genetics ; Transfection ; Tumor Suppressor Proteins ; genetics

BACKGROUNDTo establish a human large cell lung cancer cell line L9981-nm23-H1 transfected with wild type nm23-H1 gene.

METHODSpLXSN-nm23-H1-EGFP was constructed by gene clone technique, and L9981-nm23-H1 was established by infected virus of nm23-H1 gene. The DNA and protein expression of nm23-H1 were detected in the transgene large cell lung cancer cell line by PCR and Western blot.

RESULTSpLXSN-nm23-H1-EGFP was constructed successfully, and the nm23-H1 cDNA was inducted to L9981 cell. The protein of nm23-H1 could be detected in L9981-nm23-H1 cell.

CONCLUSIONSProtein of nm23-H1 is stably, continuously and high efficiently expressed in L9981-nm23-H1 cell.

BACKGROUNDTo investigate the expression features of the heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1) in non-small cell lung cancer and its clinical significance.

METHODShnRNP A2/B1 expression of cancer tissues, paracancerous lung tissues, resected bronchial stump epithelium tissues was detected in 58 non-small cell lung cancer patients and pulmonary tissues in 30 patients with benigh pulmonary lesions as control by immunohistochemistry methods.

RESULTSThe positive expressive rate of hnRNP A2/B1 in lung cancer tissue (63.79%) was significantly higher than those in paracancerous lung tissue (43.10%) and benign pulmonary lesion tissues (20.00%) (P=0.000), and the positive rate in paracancerous lung tissue was also significantly higher than that in benign pulmonary lesion tissues (P < 0.05). The positive rate of hnRNP A2/B1 in the hyperplastic and dysplastic epithelium (40.00%) of resected bronchial stump was remarkably higher than that in normal bronchial epithelium (15.15%) in lung cancer patients (P=0.032). The positive rate of hnRNP A2/B1 in poor differentiated lung cancer (78.13%) was remarkably higher than that in moderate and well differentiated lung cancer (46.15%) (P < 0.05). The positive rate of hnRNP A2/B1 in lung cancer with lymph node metastasis (75.00%) was significantly higher than that without lymph node metastasis (50.00%) (P < 0.05). The positive rate of hnRNP A2/B1 in stage III+IV disease (78.57%) was significantly higher than that in stage I+II disease (50.00%) (P < 0.05). The positive rate of hnRNP A2/B1 in T3+T4 cancer (77.42%) was significantly higher than that in T1+T2 cancer (48.15%) (P < 0.05). The positive rate of hnRNP A2/B1 expression in lung cancer tissues was not related to histological classification of the cancer (P > 0.05).

CONCLUSIONSThe overexpression of hnRNP A2/B1 in cancer tissues may play an important role in the oncogenesis, development and metastasis of lung cancer. Detection of hnRNP A2/B1 expression may be helpful to diagnose lung cancer and to predict prognosis of the patients with lung cancer.