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

The regulation of expression of parathyroid hormone-related protein (PTHRP) mRNA by protein kinase C and cyclic-AMP-dependent pathways was studied in a human lung cancer cell line (BEN). PTHRP mRNA was increased by agents which activate protein kinase C, but not by those which activate cyclic-AMP-dependent pathways. Activators of both second messenger pathways stimulated a dose-dependent increase in the accumulation of PTHRP in conditioned medium assayed using sensitive region-specific immunoassays for PTHRP1-34 and 1-86. Calcitonin had a dose-dependent effect on the accumulation of PTHRP in culture medium which may be mediated via cyclic AMP. Varying the calcium concentration from 0-2.5 mM had no effect on peptide secretion over 20 h, while short-term incubation (30 min) with ionomycin (2.5-75 micrograms/ml) significantly increased PTHRP immunoreactivity in the medium.
 ...
PMID:Expression and secretion of parathyroid hormone-related protein by a human cancer cell line. 831 63

Anticancer drug development has recently shifted in part to development of more innovative anticancer agents. The increasing knowledge of the pathogenetic mechanisms involved in cancer cell growth has enabled the introduction of drug screening that is more mechanism-based. The realization that new targets should be preferentially evaluated as sites for anticancer drug treatment has led to the introduction of drugs such as the taxanes. Following this logic, several new drugs are being developed. Minor groove-binding agents such as carzelesin and oral platins lacking organ toxicity, such as JM216, have recently entered clinical studies. The activity of gemcitabine is a result of its being a cytidine analogue and being competitively incorporated by DNA; the drug has shown interesting activity in non-small-cell lung cancer and, although registration is imminent, issues regarding the optimal dose and administration schedule have yet to be resolved. Tomudex is a thymidylate synthase inhibitor with interesting activity in colorectal cancer. Activity in colorectal cancer is also of interest for irinotecan, the first clinically applied topoisomerase I inhibitor, an enzyme that is another example of a new target for anticancer drugs. Irinotecan has produced consistent response rates of 20-30% in six different studies in colorectal cancer. The other topoisomerase I inhibitor that is in the advanced stage of development is topotecan. This drug has shown activity in second-line chemotherapy for ovarian cancer and small-cell lung cancer. Another interesting feature of topotecan is the availability of an oral formulation with consistent bioavailability. Drugs interfering with cellular signal transduction, such as the protein kinase C inhibitors, are in the development spotlight. Finally, the use of old drugs in new ways, such as immunoconjugates of doxorubicin, holds promise for the near future.
 ...
PMID:New promising anticancer agents in development: what comes next? 876 8

CGP 41251 (4'-N-benzoyl staurosporine, CAS 120685-11-2) has been shown to exert increased selectivity for the inhibition of protein kinase C (PKC) activity. In the present study the effect of CGP 41251 formulated in gelucire as an antitumor agent was studied in various types of murine and human tumor models. When administered at a dose of 75 mg/kg 3 times daily for 9 days, CGP 41251 prolonged the life span of the mice bearing B16 melanoma (ILS = 36%). CGP 41251, administered orally at doses of 25-225 mg/kg once daily for 9 days, however, did not show distinct efficacy in four kinds of murine tumor models (B16 melanoma, colon 26, colon 38 and M5076). In s.c.inoculated human tumor xenograft models, CGP 41251, administered orally at a dose of 200 mg/kg once daily for 4 weeks showed a broad antitumor spectrum. CGP 41251 inhibited the growth of gastric cancer (H-55), colorectal cancer (H-26), breast cancer (H-31) and lung cancer (H-74 and LC-376) with inhibition rates of 58-80%. In a histopathologic study, increase in central necrosis and condensed nuclei and vacuolar degeneration were observed, but there was no structural destruction by the treatment of CGP 41251. In addition, CGP 41251 decreased the number of PCNA (proliferating cell nuclear antigen) immunoreactive cells in human tumor cells H-55, H-26 and H-74. These results indicate that CGP 41251 shows a broad antitumor spectrum against human tumors, and it is suggested that CGP 41251 is a promising oral antitumor agent which has a novel mechanism of action.
 ...
PMID:Antitumor activity of the new selective protein kinase C inhibitor 4'-N-benzoyl staurosporine on murine and human tumor models. 892 45

Cholera toxin (ChT) inhibits signals generated by multiple growth factors in human lung cancer cells, resulting in cell growth inhibition. We now report that ChT triggers apoptosis as shown by DNA fragmentation and activation of caspases cleaving poly(ADP-ribose) polymerase and lamin B. Apoptosis induced by ChT in a small cell lung cancer cell line is not affected by manipulations of intracellular cAMP through preincubation with isobutylmethylxanthine but can be modestly increased through inhibition of protein kinase C with chelerythrine. Thus, apoptosis is actively suppressed in lung cancer cells by a ChT-sensitive-growth regulatory pathway, and these observations may have significant implications in the development of novel strategies for lung cancer treatment.
 ...
PMID:Cholera toxin triggers apoptosis in human lung cancer cell lines. 920 66

Transforming growth factor-beta (TGF-beta) mediates the production of extracellular matrix proteins, proteases and protease inhibitors in epithelial cells. Both TGF-beta and phorbol-12-myristate-13-acetate (PMA) exert both positive and negative effects on mitogenesis in these as well as other cell types. Phorbol esters act through stimulation of protein kinase C (PKC) and are among the most potent tumor promoters known. The present study was conducted to determine whether the effect of TGF-beta in human non-small cell lung cancer (NSCLC) and normal human bronchial epithelial (NHBE) cells parallels that of the phorbol esters and whether this effect of TGF-beta involves PKC. TGF-beta 1 and PMA increased expression of TGF-beta 1 mRNA 24 hr after their addition to both NSCLC and NHBE cells. The effects of these agents on expression of the mRNAs for TGF-beta 2 and TGF-beta 3 were more complex; while TGF-beta 2 and TGF-beta 3 mRNAs increased transiently in response to TGF-beta 1 in NHBE cells and TGF-beta 3 mRNA increased transiently in some NSCLC cells, expression of these mRNAs decreased in most of these cells in response to PMA with the exception of the carcinoid NCI-H727 where TGF-beta 2 mRNA increased dramatically, TGF-beta 1 and PMA both caused a persistent increase in expression of the mRNAs for both plasminogen activator inhibitor-1 (PAI-1) and plasminogen activator (PA) up to 24 hr in most NSCLC cells, with the increase in PAI-1 mRNA beginning several hours before that of PA mRNA. In contrast, while TGF-beta 1 also increased expression of PAI-1 mRNA in NHBE cells, the expression of PA mRNA decreased simultaneously. The effect of PMA on PAI-1 and PA mRNAs was opposite of TGF-beta 1 in these cells, with expression of PAI-1 mRNA decreasing and PA mRNA increasing after addition of PMA. These data show that there is parallel regulation of the genes for TGF-beta 1, PAI-1 and PA by TGF-beta 1 and PMA in NSCLC, but differential regulation of the genes for PAI-1 and PA by these agents in NHBE cells. The responses of the mRNAs and proteins of TGF-beta 1, PAI-1 and PA to TGF-beta 1 and PMA were inhibited by the serine/ threonine kinase inhibitor H7 in NSCLC cells. Treatment of NSCLC cells with TGF-beta 1 and PMA resulted in a persistent increase in the expression of fibronectin mRNA and protein. This response was blocked by the addition of H7. Inhibition of these effects by H7 in NSCLC cells suggests that H7 blocks TGF-beta responses by inhibiting a protein serine/threonine kinase(s). Because the effects of TGF-beta and PMA on the different TGF-beta isoforms, PA, PAI and fibronectin in NHBE and NSCLC cells are complex, our data suggest that there are distinct mechanisms for controlling the different TGF-beta isoforms, PA, PAI and extracellular matrix proteins in normal lung and lung cancer cells.
 ...
PMID:Effects of transforming growth factor-beta 1 and phorbol ester on PAI-1 and PA genes in human lung cells. 925 8

A possible link between protein kinase C (PKC) and P-glycoprotein (P-gp)-mediated-multidrug resistance (MDR) was assumed from studies on MDR cell lines selected in vitro. The functional relevance of PKC for the MDR phenotype remains unclear, and the involvement of a particular PKC isozyme in clinically occurring drug resistance is not known. Recently, we have demonstrated significant correlations between the expression levels of the PKC eta isozyme and the MDR1 or MRP (multidrug resistance-associated protein) genes in blasts from patients with acute myelogenous leukaemia (AML) and in ascites cell aspirates from ovarian cancer patients. To extend these findings to further types of human tumours we analysed specimens from 64 patients with primary breast cancer for their individual expression levels of several MDR-associated genes (MDR1, MRP, LRP (lung cancer resistance-related protein), topoisomerase (Topo) II alpha/IIbeta, cyclin A and the PKC isozyme genes (alpha, beta1, beta2, eta, theta, and mu) by a cDNA-PCR approach. We found significantly enhanced mean values for MRP, LRP and PKC eta gene expression, but significantly decreased Topo II alpha and cyclin A gene expression levels in G2 tumours compared with G3. Remarkably, significant positive correlations between the MDR1, MRP or LRP gene expression levels and PKC eta were determined: MDR1/PKC eta (rs = +0.6451, P < 0.0001) n = 62; MRP/PKC eta (rs = +0.5454, P < 0.0001) n = 63; LRP/PKC eta (rs = +0.5436, P < 0.0001) n = 62; MRP/LRP (rs = +0.7703, P < 0.0001) and n = 62, MDR1/MRP (rs = +0.5042, P < 0.0001) n = 62. Our findings point to the occurrence of a multifactorial MDR in the clinics and to PKC eta as a possible key regulatory factor for up-regulation of a series of MDR-associated genes in different types of tumours.
 ...
PMID:Multiple gene expression analysis reveals distinct differences between G2 and G3 stage breast cancers, and correlations of PKC eta with MDR1, MRP and LRP gene expression. 945 50

Although nicotine has been implicated as a potential factor in the pathogenesis of human lung cancer, its mechanism of action in the development of this cancer remains largely unknown. The present study provides evidence that nicotine (a) activates the mitogen-activated protein (MAP) kinase signalling pathway in lung cancer cells, specifically extracellular signal-regulated kinase (ERK2), resulting in increased expression of the bcl-2 protein and inhibition of apoptosis in these cells; and (b) blocks the inhibition of protein kinase C (PKC) and ERK2 activity in lung cancer cells by anti-cancer agents, such as therapeutic opioid drugs, and thus can adversely affect cancer therapy. Nicotine appears to have no effect on the activities of c-jun NH2-terminal protein kinase (JNK) and p38 MAP kinases, which have also been shown to be involved in apoptosis. While exposure to nicotine can result in the activation of the two major signalling pathways (MAP kinase and PKC) that are known to inhibit apoptosis, nicotine regulation of MAP (ERK2) kinase activity is not dependent on PKC. These effects of nicotine occur at concentrations of 1 microM or less, that are generally found in the blood of smokers, and could lead to disruption of the critical balance between cell death and proliferation, resulting in the unregulated growth of cells. The findings suggest caution in the use of smokeless tobacco products to treat smoking addiction, as they could have a potentially deleterious effect in patients with undetectable early tumour development.
 ...
PMID:Signalling pathways involved in nicotine regulation of apoptosis of human lung cancer cells. 960 Mar 37

The role of calcitonin, and other agonists which activate the cAMP pathway, in regulating transcription of the human parathyroid hormone-related protein (PTHrP) gene was investigated in a human lung cancer cell line (BEN). Both calcitonin and forskolin caused a 5-6-fold increase in transcription initiated from both the P1 and P3 promoters, but with no observed effect on the P2 promoter. Maximal 6-fold activation of the P1 promoter occurred at 16 h post-stimulation and effects of calcitonin were observed within the pM range. The PKC agonist, phorbol 12-myristate 13-acetate diester (PMA), did not modulate transcription initiated from the P1 promoter. The ionophore ionomycin had a small effect on transcription of the P1 promoter, and transcriptional control may involve an interaction between the cAMP and intracellular calcium second messenger pathways. Deletion mapping studies indicated that increases in transcription of the human PTHrP gene is being mediated via a CRE element situated at -3313 to -3306 upstream of the P1 promoter. Mutational analysis of this CRE element confirmed a role for this sequence in mediating the increase in transcription effected by cAMP. Consistent with these transfection studies, RT-PCR of PTHrP mRNA also indicated a significant increase in transcripts generated from the P1 promoter. Gel retardation assays utilising a fragment of the P1 promoter region, encompassing the putative CRE, determined that nuclear proteins were binding to this region. Competition binding studies with labelled probe and cold competitors determined that the binding was specific for this sequence. A wild-type CRE consensus oligonucleotide also competed for binding with this sequence.
 ...
PMID:Differential regulation of the parathyroid hormone-related protein gene P1 and P3 promoters by cAMP. 968 26

Using a pure chemotactic model, we investigated the effect of plasmin on tumor cell motility. In the presence of various extracellular matrix proteins, plasmin facilitated motility of human melanoma LOX and lung cancer Lu-99 cells. Laminin contributed most to the action of plasmin. The cell motility induced by plasmin and laminin was chemokinetic in nature and was almost completely suppressed by alpha2-antiplasmin. To further characterize the action of plasmin, various signal transduction kinase inhibitors were tried out. The results suggested that plasmin may modulate cell motility through protein kinase C and mitogen-activated protein kinase cascades in cooperation with laminin.
 ...
PMID:Modulation of tumor cell motility by plasmin. 994 91

To investigate the effects of exposure to sidestream cigarette smoke (CS) on the initiation and promotion of lung cancer, two groups of 8 or 10 rats were exposed to CS for a 1 h period twice a day for 8, 12, or 20 weeks. The protein kinase C (PKC) activity of the lung exhibited significant changes of 120, 86 and 81% in the CS groups, compared with the respective control group values in the three exposure periods. The in vitro activation of PKC by the active oxygens was efficiently eliminated by hydroxyl radical scavengers, indicating that hydroxyl radicals are responsible for the PKC activation. For the alterations in the lung nucleus caused by passive smoking, the 12- and 20-week exposure CS groups showed significant increases in the accumulation of 8-hydroxydeoxyguanosine. One rat with K-ras activation by G:C transversion (GGT-->GCT) at codon 12 was found among 26 rats of the CS groups in the three exposure periods. These results show that active oxygens introduced by passive smoking may contribute to K-ras activation as an initiator of a tumor model, possibly through the oxygen-induced DNA damage, and may also contribute to an initial activation and the subsequent down-regulation of PKC as a promoter.
 ...
PMID:Alterations of protein kinase C, 8-hydroxydeoxyguanosine, and K-ras oncogene in rat lungs exposed to passive smoking. 1055 60


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>