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Query: UMLS:C0242379 (lung cancer)
 71,905 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Overexpression of c-raf-1 and the myc family of protooncogenes is primarily associated with small cell carcinoma, which accounts for approximately 25% of human lung cancer. To determine the functional significance of the c-raf-1 and/or c-myc gene expression in lung carcinogenesis and to delineate the relationship between protooncogene expression and tumor phenotype, we introduced both protooncogenes, alone or in combination, into human bronchial epithelial cells. Two retroviral recombinants, pZip-raf and pZip-myc, containing the complete coding sequences of the human c-raf-1 and murine c-myc genes, respectively, were constructed and transfected into simian virus 40 large tumor antigen-immortalized bronchial epithelial cells (BEAS-2B); this was followed by selection for G418 resistance. BEAS-2B cells expressing both the transfected c-raf-1 and c-myc sequences formed large cell carcinomas in athymic nude mice with a latency of 4-21 weeks, whereas either pZip-raf- or pZip-myc-transfected cells were nontumorigenic after 12 months. Cell lines established from tumors (designated RMT) revealed the presence of the cotransfected c-raf-1 and c-myc sequences and expressed morphological, chromosomal, and isoenzyme markers, which identified BEAS-2B cells as the progenitor line of the tumors. A significant increase in the mRNA levels of neuron-specific enolase was detected in BEAS-2B cells containing both the c-raf-1 and c-myc genes and derived tumor cell lines. The data demonstrate that the concomitant expression of the c-raf and c-myc protooncogenes causes neoplastic transformation of human bronchial epithelial cells resulting in large cell carcinomas with certain neuroendocrine markers. The presented model system should be useful in studies of molecular events involved in multistage lung carcinogenesis.
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PMID:Cooperation of c-raf-1 and c-myc protooncogenes in the neoplastic transformation of simian virus 40 large tumor antigen-immortalized human bronchial epithelial cells. 255 16

Mouse spleen cells transfected with pSV2 neo by CaPO4 precipitation were fused with highly metastatic cell clone (PLA801-D95) from human large cell lung cancer cell line. Hybrid cell clone PMS-2 was obtained after G418(400/ml)selection. After injection of 7 x 10(6) PMS-2 cells into nude mice, there was a tumor nodule developed, but the metastatic foci could not be found while 3 x 10(6) PLA801-D95 cells would metastasize to lung and lymph nodes after they were injected into nude mice. It might indicate that sometime mouse spleen cells could not suppress tumor formation but the metastatic potential could be suppressed by the fusion of mouse spleen cells with the lung cancer cells. The results of growth curve, serum independence and incorporation rates of H-thymidine all showed that the growth rates of parental cells were higher than those of PMS-2. Our data suggest that suppression of tumorigenicity and metastatic potential could be controlled by different kinds of genes, and the cloning of metastasis suppressor gene by subtractive hybridization is ongoing in our laboratory.
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PMID:[A primary observation on the effect of cell fusion on metastatic potential of tumor cells]. 870 58

To understand the skeletal metastatic pattern of non-small cell lung cancer, we developed a stable high-expression green fluorescent protein (GFP) transductant of human lung cancer cell line H460 (H460-GFP). The GFP-expressing lung cancer was visualized to metastasize widely throughout the skeleton when implanted orthotopically in nude mice. H460 was transduced with the pLEIN retroviral expression vector containing the enhanced GFP and the neomycin (G418) resistance gene. A stable high GFP-expressing clone was selected in vitro using 800 microg/ml G418. Stable high-level expression of GFP was maintained in s.c.-growing tumors formed after injecting H460-GFP cells in nude mice. To use H460-GFP for visualization of metastasis, fragments of s.c.-growing H460-GFP tumors were implanted by surgical orthotopic implantation in the left lung of nude mice. Subsequent micrometastases were visualized by GFP fluorescence in the contralateral lung, plural membrane, and widely throughout the skeletal system including the skull, vertebra, femur, tibia, pelvis, and bone marrow of the femur and tibia. The use of GFP-expressing H460 cells transplanted by surgical orthotopic implantation revealed the extensive metastatic potential of lung cancer in particular to widely disseminated sites throughout the skeleton. This new metastatic model can play a critical role in the study of the mechanism of skeletal and other metastasis in lung cancer and in screening of therapeutics that prevent or reverse this process.
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PMID:Widespread skeletal metastatic potential of human lung cancer revealed by green fluorescent protein expression. 976 40

Human lung cancer leads the mortality of cancers and the chemotherapy is often uneffective because of drug resistance. In order to study the role of mdr-1 gene in resistant lung cancer, the fully length mdr-1 cDNA was transferred into a sensitive lung cancer cell line GLC. The mdr-1 cDNA was constructed in a retroviral vector, pDORneo. The transfection of recombinant plasmid was carried out by lipofectin. Supernatant containing infective viruses derived from a G418 resistant clone of package cell PA317 was used to infect GLC cell which is sensitive to chemotherapeutic agents. After G418 and adriamycine selections, three P-glycoprotein positive clones were isolated and the integration of mdr-1 cDNA was demonstrated by PCR of genomic DNA. The relative resistance of 3 clones to adriamycine as and elevated by 5.4, 6.0 respectively 7.8 times compared with the untransfected cell and the transcription of mdr-1 gene in these transfected cells as obviously enhanced by in situ hybridization. This results suggest that the mdr-1 gene plays a role in increasing drug resistance of human lung cancer.
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PMID:[Fully length MDR1 cDNA transfer conferring resistance to adriamycine on sensitive cells GLC]. 1045 56

It has been shown that the type IV collagenase with its two subtypes, 72 kDa/ MMP-2 and 92 kDa/MMP-9, plays an important role in tumor invasion and metastasis formation that occur through a mechanism of proteolytic degradation of collagen IV in the basement membrane. One possible method to specifically inhibit the function of the targeted protein of a cell is to express intracellular antibody combining site that can block the function or prevent the expression of the targeted molecule. Accordingly, intracellular antibodies against type IV collagenase may have a therapeutic use against tumor invasion and metastasis. As described in our previous reports, an anti-type IV collagenase monoclonal antibody (3D6) was obtained using the hybridoma approach, and its functional single-chain Fv fragment (scFv) named M97 was constructed based on recombinant phage display techniques. In this study, the endoplasmic reticulum (ER)-retained scFv antibody fragment was used to inhibit the function of type IV collagenase. For expression in mammalian cells, the assembled scFv M97 gene with ER retention signal encoding 6 additional amino acid (SEKDEL) was reamplified by PCR. The amplified fragments were cloned into the pcDNA3.1 vector containing the CMV early-intermediate promoter/enhancer. The resulting plasmid was sequenced and then introduced by the lipofectamine method into PG cells, a highly metastatic human lung cancer cell line and G418-resistant cells were obtained by G418 selection. After transfection, the M97 mRNA expression was observed and the type IV collagenase expression was downregulated significantly as measured by ELISA. The biological behavior of PG cells, such as the ability of in vitro invasion of colony formation on soft agar through Matrigel, were also inhibited by scFv M97 transfection. The results indicate that intracellular antibody technology represents a novel and efficient way to selectively abrogate the activity of type IV collagenase, at least in vitro. We are presently exploring the efficacy of this approach in a xenograft model of human lung cancer.
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PMID:Antineoplastic effect of intracellular expression of a single-chain antibody directed against type IV collagenase. 1090 9

A monoclonal antibody, LC-1, recognizing lung cancer associated common antigens was obtained in authors' laboratory. Its single chain Fv fragment (ScFv) named LC-1 ScFv was constructed based on recombinant phage displayed techniques. For expression on cell membrane, LC-1 ScFv was cloned into pDisplay vector, which directed the cloned gene to express as cell membrane bound protein. The resulting plasmid was sequenced and then introduced by the lipofectin method into a lung adenocarcinoma cell line SPC-A-1. G418 resistant cells were obtained by G418 selection. After transfection, LC-1 ScFv expression was observed by Western blot analysis and the expression of cognate antigens was down-regulated as shown in ELISA assay. SPC-A-1-pDisplay-ScFv cells grew in vitro at lower speed than the control intact cells and the cells transfected with vacant vector. Flow cytometry analysis detected a substantial increase in G1 phase and decrease in S phase in population of SPC-A-1-pDisplay-ScFv cells compared to SPC-A-1 and SPC-A-1-pDisplay cells. Semi-quantitative RT-PCR analysis showed that c-myc expression was down-regulated in SPC-A-1-pDisplay-ScFv cells. It seems that the antigens recognized by LC-1 may be in some way involved in a growth stimulating pathway and the antibody blocking of the function of the antigens shut down the pathway and thus down-regulate the expression of c-myc and growth of the cells.
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PMID:The inhibition of lung cancer cell growth by intracellular immunization with LC-1 ScFv. 1194 10

Two p16 mutants, P48L and D74N, were obtained by site-directed mutagenesis using two step PCR method. Mutant p16 cDNA and wild-type p16 cDNA were colned into the mammalian expression vector pcDNA3 to construct p16 expression vector pCMV-p16, pCMV-p16P48L and pCMV-p16D74N, respectively. After the introduction of these expression vectors into human lung cancer cell line H460 in which endogenous p16 gene was homozygously deleted, exogenous p16 expression was detected in G418 resistant cells by Northern blotting and immunocytochemistry staining. The results of immunofluorescence and immunocytochemistry staining showed that the P16 protein was located in the cell cytoplasm. The p16 cDNAs amplificated from the genomic DNA of recombinant H460 cell lines indicated that the plasmid p16 cDNA was integrated into the chromosome of cell lines. That the over expression of wild-type p16 caused G1 arrest suggested the wild-type P16 protein expressed in H460 cell line to be a functional protein.
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PMID:Expression of Wild-type and Mutant p16 in H460 Cell Line. 1217 51

We established xenograft mouse models for studying human lung cancer by using an in vivo imaging system. We first transfected pGL4.17 (luc2/neo) plasmid into human non-small lung cancer A549 cells and screened cell lines stably expressing a luciferase reporter gene with G418. Then we analyzed the correlation of luciferase activity and cells number by in vitro bioluminescence. Furthermore, we compared cell growth characteristics by cell counting. We selected suitable clones and inoculated subcutaneously into nude mice or intravenously into SCID mice to construct lung cancer xenograft models. Using an in vivo imaging system, we monitored the growth and metastasis of the tumors. Finally, we verified the extents of tumorigenesis and metastasis by tissue sections with Hematoxylin and Eosin (HE) staining. In our study, we successfully established the xenograft mouse models for in vivo imaging with luciferase expressed lung cancer cells. These models provided convenient, sensitive, intuitive and stable tools for studying the mechanisms of lung cancer progression and development of anticancer drug.
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PMID:[Establishment of xenograft mouse models to study human lung cancer by using in vivo imaging system]. 1993 58

TNF-related apoptosis-inducing ligand (TRAIL) is a member of factor TNF family, which could be potentially developed as novel antitumor agent due to its selective and efficient induction of apoptosis in tumor cells. Gene recombinant expression is an important tool for production of pharmaceutical protein. In this paper, the gene encoding human soluble TRAIL (114-281aa fragment) was cloned by PCR and then inserted into the Pichia Pastoris expression vector pPIC9K. The transformants were double-screened on plates containing neomycin G418 and many clones with high levels of G418-resistance were selected for further studies on protein expression. The recombinant human soluble TRAIL was secreted into the BMMY media under the condition of 3% methanol. And the recombinant protein was purified to homogeneity (-80% purity) by using Ni-agarose affinity chromatography. The yield of this protein is about 1-2 mg per liter culture. Cell viability assays demonstrated that human soluble TRAIL was cytotoxic in both leukemia cells Jurkat and lung cancer cells A549. After treatment with 0.05 microg/ml TRAIL, the survival rate of Jurkat cells was about 10%. The expressed TRAIL showed dose-dependent cytotoxicity in A549 cells within the range of 0.1-1 microg/ml. When the protein concentration reached 1 microg/ml, the survival rates of A549 cells were about 30%. However, the recombinant human soluble TRAIL did not show obvious cytotoxicity in human skin fibroblast cells (HSF) at concentrations tested. There results demonstrate that human soluble TRAIL is selectively cytotoxic in tumor cells. The expression system constructed in this experiment might contribute to further production of soluble TRAIL and TRAIL-based novel fusion proteins in large quantities.
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PMID:[Cloning and recombinant expression of human soluble TRAIL in Pichia pastoris]. 2137 84

To explore the potential of the anti-sense nucleic acid of CyclinD1 in lung cancer therapy, the expression vector containing the anti-sense nucleic acid of CyclinD1 was constructed and named pcDNA3.1-CyclinD1. The A549 cells were transfected with pcDNA3.1-CyclinD1 vectors. After being screened by G418, the stable expression positive clones were obtained. MTT method and flow cytometry technique were used to detect cell proliferation and apoptosis, respectively. The results showed the transfected cells exhibited significantly increased apoptosis and inhibited cell growth, compared with negative control and empty vector groups. To investigate the mechanism for anti-sense nucleic acid of CyclinD1 inducing A549 cells apoptosis, the expression levels of retinoblastoma protein (pRb), adenovirus E2 factor-1 (E2F-1), vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-2 and MMP-9 were detected by Western blot, and the results showed the expressions of these proteins were all decreased significantly in anti-sense nucleic acid of CyclinD transfected group, compared with those in negative control and empty vector groups. In a word, anti-sense nucleic acid of CyclinD1 induces the apoptosis of lung adenocarcinoma cancer cells, and the depressions of pRb, E2F-1, VEGF, MMP-2 and MMP-9 expressions may be the possible mechanism.
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PMID:[Anti-sense nucleic acid of CyclinD1 induces apoptosis of lung adenocarcinoma cancer cell A549]. 2168 45


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