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)

Emergence of resistant mutations in drug targets represents a serious problem in the targeted chemotherapy. One challenging issue is to understand the atomic-detailed effect of the mutation on the target. Another intriguing issue is how to predict specific mutations that would show up in the clinical setting, leading to drug resistance. By computational approaches, we have investigated structural, dynamics and energetic effects of a series of EGFR mutations identified from the lung cancer patients. We demonstrated mutation L858R caused gefitinib move closer to the hinge region, whereas T790M caused the ligand escape from the binding pocket. In particular, the T790M decreased the size of the hydrophobic slot formed by L718 and G796. This suggests that, to be effective against the T790M mutant, the inhibitors should avoid interactions with the hydrophobic slot. Mutations T790M, L858R, and their combinations are found to cause different conformational redistribution and to perturb the electrostatic potential at the ATP-binding pocket. Normal mode analysis revealed the mutations resulted in changes in the correlated movements in the protein. In an attempt to develop a computational descriptor for predicting the functional effect of EGFR mutations, we have developed a Plarm algorithm, and the Plarm score was found to be an excellent predictor of the functional impact of six clinical relevant mutations in EGFR tyrosine kinase domains, including T790M, L858R, G719C, L861Q, T790M + L858R double mutant, and delL747-P753insS. The Plarm algorithm could be readily extended to investigate other drug targets.
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PMID:Impact of EGFR point mutations on the sensitivity to gefitinib: insights from comparative structural analyses and molecular dynamics simulations. 1692 43

Somatic mutations of the PIK3CA (phosphatidylinostitol 3-kinase catalytic subunit) gene have been found in human cancer patients. Previous reports suggested that about 4% of lung cancers harbored PIK3CA gene mutations. However, the clinico-pathological background for PIK3CA gene mutations has not yet been investigated in lung cancer. We have genotyped the PIK3CA gene in Japanese lung cancer patients. The study included 235 lung cancer cases surgically removed in Nagoya City University Hospital. The two PIK3CA mutation hot spots (exon 9 and exon 20) were analyzed by real time polymerase chain reaction (PCR)-based assay. The data were confirmed by direct sequencing. In exon 9, somatic mutation was found in eight patients (3.4%). The mutation included three E542K (G1624A), three E545K (G1633A), one E542Q (G1624C), and one Q546K (C1636A). However, in exon 20, there was no mutation in our lung cancer patients. PIK3CA mutations were not correlated with gender (women versus men, p=0.4162), age (< or =60 versus >60, p=0.8027), or smoking status of the lung cancers (never versus smoker, p=0.5666). PIK3CA mutation incidence was significantly lower in adenocarcinoma (2/135, 1.5%) than in squamous cell carcinoma (5/77, 6.5%, p=0.0495). Among eight patients with a PIK3CA mutation, three patients also harbored an EGFR somatic mutation. PIK3CA gene mutations were rare in lung cancer; rarer in adenocarcinoma. Further functional analyses of the PIK3CA mutations are warranted to study if they could be the target of therapy for the lung cancer.
Lung Cancer 2006 Nov
PMID:PIK3CA mutation status in Japanese lung cancer patients. 1693 Jul 67

This review highlights the numerous molecular biology findings in the field of lung cancer with potential therapeutic impact in both the near and distant future. At least six lines of research have recently emerged as potential contributors to changes in clinical practice. Abundant pre-clinical and clinical data indicate that BRCA1 mRNA expression is a differential modulator of chemotherapy sensitivity. Low levels predict cisplatin sensitivity and antimicrotubule drug resistance, and the opposite occurs with high levels. Secondly, single nucleotide polymorphisms in the ERCC1 gene influence survival and toxicity with cisplatin-based chemotherapy. The main core of recent research has centered on EGFR mutations and gene copy numbers. For the first time, EGFR mutations have been shown to predict dramatic responses in metastatic lung adenocarcinomas, with a threefold increase in time to progression and survival in patients receiving EGFR tyrosine kinase inhibitors. In contrast, K-ras mutations confer a negative effect in these patients. Evidence has also been accumulated on the crosstalk between estrogen and EGFR receptor pathways, paving the way for clinical trials of EGFR tyrosine kinase inhibitors plus aromatase inhibitors. microRNAs control the expression of cognate target genes, and downregulation of Dicer has been shown to be a strong predictor of relapse in surgically resected non-small-cell lung cancer patients. Finally, overexpression of the Wingless-type (Wnt) genes and methylation of Wnt antagonists like WIF and secreted frizzled related proteins have been documented in non-small-cell lung cancer and are believed to be an important mechanism of cancer stem cell maintenance.
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PMID:Usefulness of predictive tests for cancer treatment. 1693 74

The EGFR is a validated anticancer target whose successful exploitation has added novel agents to our current treatment protocols. Subsets of patients have shown to benefit the most from these therapies, and though these differential responses have yet to be completely defined, they are mostly of genetic nature. Egfr amplifications have shown to increase sensitivity to both small molecule inhibitors and specific monoclonal antibodies targeting the EGFR. A somatic/germline egfr intron 1 CA repeat sequence polymorphism has shown to have an important role in the control of EGFR protein expression, and has been linked to an increased risk of familial breast cancer, a worse outcome in patients with colorectal cancer, and anti-EGFR treatment efficacy in preclinical models. Egfr activating mutations have been recently described in lung cancer linking a cluster of genotypes with sensitivity to EGFR tyrosine kinase pharmacological inhibition. Despite the initial excitement that this discovery elicited, follow-up reports have not unequivocally confirmed this finding, and these drugs have been solidly efficacious both in individual patients and in diseases generally lacking egfr mutations such as pancreas cancer. We are witnessing exciting developments in the field of the pharmacogenomics of cancer, and this has particularly evolved in the area pertaining EGFR tyrosine kinase inhibitors. This review will discuss the background and currently available preclinical and clinical data.
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PMID:Pharmacogenomics of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors. 1704 3

We conducted a feasibility study to examine whether small numbers of cancer cells could be utilised for analysis of the EGFR gene status using the loop-hybrid mobility shift assay, which is a modified heteroduplex technique. Cytology specimens obtained by transbronchial abrasion were successfully used for analysis of the EGFR gene status in 50 of 52 (96.2%) patients diagnosed with class V non-small-cell carcinoma. Furthermore, the relationship between the EGFR gene status and clinical outcome was analysed in 25 patients treated with gefitinib. Overall, 10 of 11 patients with EGFR mutations in exon 19 or 21 showed tumour regression with gefitinib treatment, compared to only two of 14 patients with wild-type EGFR. The response rate was significantly higher in the EGFR mutation group than in the wild-type EGFR group (90.9 vs 14.3%, P=0.00014). Logistic regression analysis revealed that EGFR mutations in cytology specimens represented an independent predictor of the gefitinib response. The overall and progression-free survivals were significantly longer in the EGFR mutation group than in the wild-type EGFR group (P<0.05). In conclusion, cytology specimens could be useful for analysing the EGFR status in the majority of patients with non-small-cell lung cancer to determine whether they are likely to benefit from gefitinib treatment.
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PMID:Novel heteroduplex method using small cytology specimens with a remarkably high success rate for analysing EGFR gene mutations with a significant correlation to gefitinib efficacy in non-small-cell lung cancer. 1704 54

Radiation recall dermatitis is characterized by an inflammatory reaction within a previously irradiated volume after administration of a drug. Antineoplastic drugs have mainly been involved in radiation recall reactions. This phenomenon is well known but poorly understood. Many hypotheses as stem-cell depletion in the radiotherapy field, heritable mutations within surviving stem cells, local vascular changes as well as a drug hypersensitivity reaction have been proposed to explain these reactions. In this report, we describe a non-small cell lung cancer patient treated with a carboplatin plus gemcitabine combination chemotherapy as first line followed by pemetrexed as second line therapy. Twenty-five years ago, she completed radiation therapy for breast cancer. Three days after the first cycle of pemetrexed, she presented with a radiation recall dermatitis. As EGFR-staining was negative, we rechallenged the patient with pemetrexed. Unfortunately, although less intense, we faced a recurrence of the skin reaction and pemetrexed was no longer continued.
Lung Cancer 2006 Dec
PMID:Unsuccessful rechallenge with pemetrexed after a previous radiation recall dermatitis. 1704 69

Lung cancer is the most common cause of cancer-related deaths worldwide, and the discovery and implementation of more effective therapy remains challenging. The development of agents that target the epidermal growth factor receptor/human epidermal growth factor receptor 1 (EGFR/HER1) signal transduction pathway have provided a class of novel targeted therapies that are applicable in the treatment of non-small-call lung cancer (NSCLC). Current challenges include the determination of how best these promising new agents can be integrated into current methods of treatment for patients with NSCLC, and clarification of the extent to which early lines of treatment can influence outcome in the later stages.
Lung Cancer 2006 Dec
PMID:Integrating new targeted agents into the treatment of non-small-cell lung cancer. 1705 50

Targeted therapies are now more often used in lung cancer. Inhibitors of EGFR and of angiogenesis have demonstrated a certain activity in this disease. Some experimental in vitro or in vivo studies are in favour of combined targeted therapies and radiation. For example, additive or supra-additive effects have been shown when inhibitors of the EGFR tyrosine kinase were given with radiation. In advanced lung cancer, the combination of bevacizumab with chemotherapy was demonstrated to produce better survival outcomes. But a high rate of fatal hemoptysis was reported with this drug, particularly for central and squamous tumors. This could be a limitation for its use in combination with radiation. Drugs with multiple targets are becoming available; their association with radiation seems to be promising.
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PMID:[Targeted therapies and radiotherapy in lung cancer]. 1707 84

Activating mutations in the kinase domain of the EGF receptor have been reported in non-small cell lung cancer. The majority of tumors expressing these mutants are sensitive to ATP mimetics that inhibit the EGFR tyrosine kinase. The effect of antibodies that bind to the ectodomain of the receptor is less clear. We report herein the effects and mechanisms of action of the antibody cetuximab in lung cancer cells that naturally express receptor mutations and in ErbB-null 32D hematopoietic cells transfected with mutant EGFR. Treatment with cetuximab down-regulated EGFR levels and inhibited cell growth both in vitro and in vivo. This was associated with inhibition of ligand-independent EGFR signaling. These effects were seen in 32D cells arguing the growth inhibitory action was not because of the blockade of autocrine ligand action. Both antibody-induced EGFR down-regulation and inhibition of growth required receptor dimerization as monovalent Fab fragments only eliminated receptor levels or reduced cell proliferation in the presence of antihuman IgG. Finally, cetuximab inhibited growth of H1975 lung cancer cells and xenografts, which expressed L858R/T790M EGFR and were resistant to EGFR tyrosine kinase inhibitors. These data suggest that cetuximab is an effective therapy against mutant EGFR-expressing cancer cells and thus can be considered in combination with other anti-EGFR molecules.
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PMID:Epidermal growth factor receptor (EGFR) antibody down-regulates mutant receptors and inhibits tumors expressing EGFR mutations. 1708 81

Selenium has been associated with anticancer activity by affecting multiple cellular processes. We reasoned that the simultaneous modulation of multiple radioresponse regulators by selenium should increase radiosensitivity if selenium is combined with radiation in cancer therapy. Therefore, we explored the possibility of whether we could obtain an enhancement of radiosensitivity by the combination of selenium and ionizing radiation. We used two human lung cancer cell lines, NCI-H460 and H1299, as well as a human diploid lung fibroblast, WI-38, as the normal cell counterpart. The combined treatment of the cancer cell lines with Seleno-methionine and ionizing radiation resulted in increased cell killing as assessed by clonogenic survival assay whereas it had little effect on the normal diploid WI-38 cells. The increased radiosensitivity in the cancer cells was correlated with the attenuation of the key proteins involved in either cell survival signaling [Akt, EGFR (epidermal growth factor receptor), ErbB2 and Raf1] or DNA damage response (Mre11, Rad50, Nbs1, Ku80, 53BP1 and DNAPK). The attenuation of the proteins by the selenium compound was possibly caused by the effect on transcription and on protein stability since selenium treatment decreased both the RNA transcript and the protein stability of EGFR and DNAPK. By contrast, Seleno-L-methionine had no effect on the protein profile of a normal diploid fibroblast which is consistent with an intact radiosensitivity. These data provide possible clinical applications, as selenium selectively enhanced the radiosensitivity of the tumor cells whereas that of the normal cells was unaffected. Moreover, the selective decrease of cell proliferation signaling in tumor cells but not in normal cells should facilitate the repopulation of normal cells required for healing during radiation therapy. On the whole, the results suggest that the cancer preventive activity of selenium can be combined with ionizing radiation to improve the control of lung cancer.
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PMID:Enhanced lung cancer cell killing by the combination of selenium and ionizing radiation. 1714


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