Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0242379 (lung cancer)
 71,905 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We examined the genomic status of cyclin-dependent kinase-4 and -6 inhibitors, p16INK4,p15INK4B, and p18, in 40 primary lung cancers and 31 metastatic lung cancers. Alterations of the p16INK4 gene were detected in 6 (2 insertions and 4 homozygous deletions) of 22 metastatic non-small cell lung cancers (NSCLCs; 27%), but none were detected in 25 primary NSCLCs, 15 primary small cell lung cancers (SCLCs), or 9 metastatic SCLCs, indicating that mutation in the p16INK4 gene is a late event in NSCLC carcinogenesis. Although three intragenic mutations of the p15INK4B gene were detected in 25 primary NSCLCs (12%) and five homozygous deletions of the p15INK4B gene were detected in 22 NSCLCs (23%), no genetic alterations of the p15INK4B gene were found in primary and metastatic SCLCs. The p18 gene was wild type in these 71 lung cancers, except 1 metastatic NSCLC which showed loss of heterozygosity. We also examined alterations of these three genes and expression of p16INK4 in 21 human lung cancer cell lines. Alterations of the p16INK4 and p15INK4B genes were detected in 71% of the NSCLC cell lines (n = 14) and 50% of the NSCLC cell lines (n = 14), respectively, but there were none in the 7 SCLC cell lines studied. No p18 mutations were detected in these 21 cell lines. These results indicate that both p16INK4 and p15INK4B gene mutations are associated with tumor progression of a subset of NSCLC, but not of SCLC, and that p15INK4B mutations might also be an early event in the molecular pathogenesis of a subset of NSCLC.
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PMID:Mutations in the p16INK4/MTS1/CDKN2, p15INK4B/MTS2, and p18 genes in primary and metastatic lung cancer. 788 51

Cell cycle dependent phosphorylation of the RB tumor suppressor protein is mediated by a family of G1 cyclin dependent kinases (cdks) and cyclins including the activated cdk4:cyclin D complex. The identification of a cdk4 inhibitor, p16INK4, as a target for mutations in cultured tumor lines and primary tumors suggested that RB activity may be affected in these cells. We have examined 88 lung cancer lines for p16INK4 protein expression and have observed a striking inverse correlation between the presence of p16INK4 and wildtype RB. We demonstrated that only 6/55 (11%) of small cell lung cancer (SCLC) samples had absent p16INK4 protein, and all 6 belonged to the rare subset of SCLC with wildtype RB expression. Conversely of 48 SCLC samples with absent or mutant RB, all showed detectable levels of p16INK4 protein. In contrast, we observed that 23/33 (70%) of non-SCLC samples had loss of p16INK4. Twenty-two of 26 non-SCLC lines with wildtype RB had absent p16INK4 while 6 of 7 non-SCLC lines with absent or mutant RB had detectable p16INK4. The inverse correlation of RB and p16INK4 expression and the absence of p16INK4 inactivation in RB (-/-) SCLC lines (0/48) confirms a common p16INK4/RB growth suppressor pathway in human cancers and provides evidence that p16INK4, and not an adjacent gene on chromosome 9p, is a specific target for mutational events.
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PMID:Absence of p16INK4 protein is restricted to the subset of lung cancer lines that retains wildtype RB. 793 65

Butyrolactone I, which is a naturally occurring specific inhibitor of the cdc2 kinase family, showed antitumor effects on several non-small- and small-cell-lung cancer cell lines with IC50 values the order of 50 micrograms/ml on the former. No cross-resistance of several drug-resistant cell lines, including those with the multidrug-resistant phenotype and five cisplatin-resistant cell lines to butyrolactone I was observed. The cdc2 kinase activity of PC-14 cells was inhibited by treatment with 20 micrograms/ml butyrolactone I, a concentration comparable to the IC50 value, for 2 hours. Longer exposure to butyrolactone I (> 24 hours) reduced the cdc2 kinase protein level. Butyrolactone I arrested the cells at the G2/M phase in a concentration dependent manner. These results suggest that butyrolactone I actually acts on cdc2 kinase, rather than other cdk kinases, in PC-14 cells. Inhibition of DNA synthesis, determined by measuring thymidine uptake, occurred earlier (2 hours) after initiating exposure than the decrease in the cdc2 protein level and was concentration dependent, suggesting that butyrolactone I inhibited DN4 synthesis. Cell permeabilization by digitonin enhanced DN4 synthesis inhibition by butyrolactone I, suggesting that the permeability of the membrane to this agent was the limiting factor for its growth inhibitory effect. Many anticancer agents, such as alkylating agents and cisplatin, cause cells to accumulate at the G2/M phase of the cell cycle. We investigated whether butyrolactone I had any modulatory effect on the antitumor effects of several anticancer drugs in vitro. Butyrolactone I showed no modulatory effects on vindesine, paclitaxel, or etoposide, but exposure of PC-9 and PC-14 cells to butyrolactone I together with or prior to treatment with cisplatin reduced the cytotoxicity of the latter. Thin-layer chromatographic analysis revealed that butyrolactone I bound to cisplatin, which was a possible cause of the reduced cisplatin cytotoxicity in the presence of bytyrolactone I.
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PMID:Antitumor effects of butyrolactone I, a selective cdc2 kinase inhibitor, on human lung cancer cell lines. 904 96

Microtubules are one of the major filament of the cytoskelton and play a role in various biological functions such as mitosis, cell motility and intracellular transport. Therefore, microtubules are considered one of the most important molecular targets for cancer chemotherapy. Tubulin is one of the major microtubular components, and its polymerization and depolymerization regulate microtubular dynamics. Other microtubular components such as microtubule-associated protein (MAPs), actin, and intermediate and microfilaments have also been demonstrated to be involved in microtubular dynamics. Recent studies provide evidence that the functions of MAPs and filaments in microtubule assembly are regulated by phosphorylation, which is catalyzed by mitogenactivated protein kinase (MAP kinase) and cdc2 kinase. Antimitotic agents that disrupt microtubules can be classified in two categories according to the mechanism of action, vinca alkaloids and taxanes. Vinca alkoloids, estramustine, rhizoxin, and E7010 inhibit microtubule polymerization. In contrast, taxanes such as paclitaxel and docetaxel promote polymerization of microtubules and enhance microtubule stability. We have demonstrated that paclitaxel inhibits the catalytic activity of MAP kinase and cdc2 kinase in lung cancer cell lines. This biological effect may be responsible for the increased affinity between MAP2 and tubulins, resulting in promotion of microtubule assembly. Factors that contribute to the resistance to antimitotic agents include intracellular accumulation of the drugs, genetic or functional alternations in tubulin, and alternations in MAP kinase cascade. Antimitotic agents showed a broad spectrum of preclinical antitumor activity. Clinical trials of taxanes revealed that they were effective for several cancers which were advanced or resistant against other anticancer drugs, especially for breast cancers, ovarian cancers and non-small cell lung cancers.
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PMID:[Antimitotic agents]. 930 50

To investigate the role of cyclin D1 in the regulation of lung cancer cell growth, we created five stably transfected cell lines carrying a cyclin D1 antisense construct. The transfected cells exhibited a marked decrease in the rate of cell growth, in contrast to the original lines (A549 and NCI-H441). The expression of several cell cycle-regulating proteins, including cyclin A, the cyclin-dependent kinases (cdk) 2 and cdk4, in addition to cyclin D1 itself, was markedly decreased. The expression of one cdk inhibitor, p21WAF1/CIP1, increased in the A549-derived cell lines. A specific target of cyclin D1 activity, the growth-suppressing product of the retinoblastoma gene, pRb, exhibited decreased expression and a decreased level of phosphorylation in the transfected cells. Decreased expression of pRb due to a significant increase in its turnover rate suggested that the stability of the protein may depend on phosphorylation by cyclin D1-dependent cdk activity. In addition to the impact on pRb stability, decreased expression of cyclin D1 induced susceptibility to cell death after withdrawal of exogenous growth factors in the antisense transfected cell lines, a response that was not observed in the original cancer cell lines. We conclude that abrogation of cyclin D1 overexpression in lung cancer cells disrupts several key pathways that are required for uncontrolled cell growth and induces those that lead to cell death after growth factor deprivation. Therefore, we speculate that use of antisense cyclin D1 expression in appropriate gene vectors could be a useful method for retarding lung cancer cell growth in accessible tumors such as those of the lung epithelium.
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PMID:Cyclin D1 antisense RNA destabilizes pRb and retards lung cancer cell growth. 937 20

Cyclin D1 dysregulation and differential inactivation of p16INK4a and Rb have been observed in human lung cancer. In chemically induced mouse lung tumors, the p16INK4a gene is a target of inactivation, and Rb is reduced at the mRNA level (Northern blot) although similar at the protein level (Western blot) when compared to normal lung tissues. The expression of cyclin D1, cdk4, p16INK4a, and Rb protein was examined by immunohistochemistry in 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced mouse lung tumors. Immunohistochemical staining revealed exclusive nuclear staining of both cyclin D1 and cdk4 that was light to moderate in normal mouse lung tissues, but intense in lung adenomas and adenocarcinomas. Western blot analysis confirmed the increased expression of cyclin D1 and cdk4 in lung tumors compared to normal lung. Immunohistochemical analyses of lung tumors showed focal areas which lacked p16INK4a staining. Expression of p16INK4a, as determined by RT-PCR, was variable in lung tumors. Mutations in p16INK4a were not found by SSCP analysis. Immunohistochemical analyses of normal lung tissues showed intense staining for Rb protein in alveolar epithelial cells and in other lung cell types; however, in the lung tumors the staining intensity was reduced and the distribution was altered. Expression of Rb was detected in normal lung tissues but was barely detectable by Northern blot hybridization in lung tumors. Western blot analysis indicated the presence of both hypophosphorylated and hyperphosphorylated Rb protein in lung tumors and in normal lung tissues. These results suggest that alterations in the cell cycle proteins, cyclin D1, cdk4, p16INK4a, and Rb, may play a role in the acquisition of autonomous growth by adenomas. Furthermore, they demonstrate the importance of immunohistochemical studies to examine expression in tissues that contain multiple cell types, such as the lung, and in tumors that by nature are heterogeneous.
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PMID:Expression of cell cycle proteins in 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced mouse lung tumors. 965 80

We earlier reported that TIS21 mRNA expression was markedly decreased in A549 and NCIH69 human lung cancer cells and in thymic carcinoma tissues obtained from transgenic mice containing simian virus 40 large T antigen (J Cancer Res Clin Oncol 121:279-284, 1995). To determine how TIS21 inhibits growth, we made 293 cells that constitutively expressed TIS21 protein. The constitutive TIS21 expresser lines C9 and C11 grew to a lower saturation density than did those in the vector-transfected clones (V7 and V10) and antisense-transfected clones (AS1 and AS4), and the size of the C9 and C11 cells increased significantly after transfection with TIS21 cDNA. The serum-stimulated cell cycle was analyzed by fluorescence-activated cell sorting after double thymidine treatment; V10 progressed normally through the cell division cycle, but C9 and C11 cells accumulated continuously in G1 phase until 36 h after treatment. On the other hand, the progression of cells that had already entered to S or G2/M phase was not inhibited. When cell-cycle regulatory proteins were measured, C9 and C11 cells showed significantly reduced synthesis of cyclin E and cyclin-dependent kinase (cdk) 4 as well as a decrease in cyclin E-associated cdk activity. These observations led us to conclude that TIS21 overexpression in G1 phase decreased the amounts of cyclin E and cdk4, thereby decreasing the activity of cdks at the G1-S transition.
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PMID:Induction of growth inhibition of 293 cells by downregulation of the cyclin E and cyclin-dependent kinase 4 proteins due to overexpression of TIS21. 976 35

The CDK inhibitor p21waf is a principal mediator of p53 function but can also be transactivated by many p53-independent stimuli leading to cell growth arrest or differentiation. In order to study the function of p21waf in a p53-deficient environment, we established an inducible expression of p21waf in the p53-null lung cancer cell line H1299, based on the muristerone-regulated system. Overexpression of p21waf led cells to growth arrest which after several days became irreversible and the arrested cells acquired a senescent phenotype as judged by cell shape, the senescence-associated beta-gal marker and inhibition of colony formation. The effect of p21waf overexpression, in the absence of p53, on the cytotoxicity caused by irradiation, doxorubicin and taxol was studied. Expression of p21waf provided protection against the cytotoxic effect of radiation and doxorubicin but not of taxol. These results are relevant to treatment of cancer when p53 is inactive.
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PMID:Induced p21waf expression in H1299 cell line promotes cell senescence and protects against cytotoxic effect of radiation and doxorubicin. 1035 8

The cyclin-dependent kinase inhibitor 2a (Cdkn2a) locus encodes two distinct tumor suppressors, p16INK4a and p19ARF, whose functions interrelate in the regulation of cell proliferation as key components of the retinoblastoma and p53 pathways, respectively. In many types of cancer, alterations of Cdkn2a abrogate the functions of both suppressors, implying that both are integral to the genesis of certain cancer types. While this has been observed in mouse lung adenocarcinogenesis, recent observations also suggested that naturally occurring variation at the Cdkn2a locus is probably operative in the development of these tumors. Firstly, two common haplotypes of mouse Cdkn2a have been identified, each of which encodes cosegregating variants of p16INK4a and p19ARF. The p16INK4a variants differ at amino acids 18 (histidine or proline) and 51 (valine or isoleucine), whereas the p19ARF variants differ only at amino acid 72 (histidine or arginine). Secondly, genetic resistance to lung tumor formation appears to segregate with one particular haplotype, which also is deleted preferentially in lung adenocarcinomas of Cdkn2a heterozygous mice. Here we attempt to explain these observations and to characterize further the roles of p16INK4 and p19ARF in mouse lung tumorigenesis by examining the function and expression of each of the variants of Cdkn2a. Functional analysis showed that the proline 18/isoleucine 51 p16INK4a variant was diminished in cdk6 binding, cdk6 inhibition and NIH/3T3 fibroblast growth suppression compared with the histidine 18/valine 51 variant, whereas both of the p19ARF variants suppressed growth with similar potencies. Also, the different alleles for p16INK4a and p19ARF were transcribed equally in the normal lungs of Cdkn2a heterozygotes, as determined by comparative reverse transcription-polymerase chain reaction-single-stranded conformation polymorphism analysis. These results indicate that strain-specific variation in p16INK4a function is exploited in mouse lung tumorigenesis and strongly implicate a role for p16INK4a in lung cancer predisposition and development.
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PMID:Cdkn2a encodes functional variation of p16INK4a but not p19ARF, which confers selection in mouse lung tumorigenesis. 1036 10

Studies on cell cycle regulation and cancer genetics have revealed that multiple cell cycle regulatory proteins play key roles in oncogenesis. These can be categorized in three sets. First; p16INK4-Cyclin D1-RB pathway, which controls G1 to S progression of the cell cycle, second; p53 pathway, which is involved in DNA damage repair, and third; p27KIP1 CDK inhibitor, a negative regulator of cell cycle, and decreased expression of which has been correlated to poor prognosis in cancer patients. Among these, p16INK4, RB and p53 are tumor suppressor genes, and p27 has been pointed out to be haplo-insufficient for tumor suppression. Involvement of these cell cycle regulatory proteins in lung cancer will be discussed.
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PMID:[Deregulation of cell cycle control in lung cancer]. 1082 44


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