Changing Rates of Adenocarcinoma of the Lung

A prognostic 4-gene expression signature for squamous cell lung carcinoma

Squamous cell lung carcinoma (SQCLC), a common and fatal subtype of lung cancer, caused lots of mortalities and showed different outcomes in prognosis. This study was to screen key genes and to figure a prognostic signature to cluster the patients with SQCLC. RNA-Seq data from 550 patients with SQCLC were downloaded from The Cancer Genome Atlas (TCGA). Genetically changed genes were identified and analyzed in univariate survival analysis. Genes significantly influencing prognosis were selected with frequency higher than 100 in lasso regression. Meanwhile, area under the curve (AUC) values and hazard ratios (HR) for seed genes were obtained with R Language. Functional enrichment analysis was performed and clustering effectiveness of the selected common gene set was analyzed with Kaplan-Meier. Finally, the stability and validity of the optimal clustering model were verified. A total of 7,222 genetically changed genes were screened, including 1,045 ones with p < 0.05, 1,746, p < 0.1, and 2,758, p < 0.2. The common gene sets with more than 100 frequencies were 14-Genes, 10-Genes and 6-Genes. Genes with p < 0.05 participated in positive regulation of ERK1 and ERK2 cascade, angiogenesis, platelet degranulation, cell-matrix adhesion, extracellular matrix organization, macrophage activation, and so on. A four-gene clustering model in 14-Genes (DPPA, TTTY16, TRIM58, HKDC1, ZNF589, ALDH7A1, LINC01426, IL19, LOC101928358, TMEM92, HRASLS, JPH1, LOC100288778, GCGR) was verified as the optimal. The discovery of four-gene clustering model in 14-Genes can cluster the patient samples effectively. This model would help predict the outcomes of patients with SQCLC then improve the treatment strategies.

Context Matters: Contribution of Specific DNA Adducts to the Genotoxic Properties of the Tobacco-Specific Nitrosamine NNK

The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent pulmonary carcinogen in laboratory animals. It is classified as a Group 1 human carcinogen by the International Agency for Cancer Research. NNK is bioactivated upon cytochrome P450 catalyzed hydroxylation of the carbon atoms adjacent to the nitrosamino group to both methylating and pyridyloxobutylating agents. Both pathways generate a spectrum of DNA damage that contributes to the overall mutagenic and toxic properties of this compound. NNK is also reduced to form 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), which is also carcinogenic. Like NNK, NNAL requires metabolic activation to DNA alkylating agents. Methyl hydroxylation of NNAL generates pyridylhydroxybutyl DNA adducts, and methylene hydroxylation leads to DNA methyl adducts. The consequence of this complex metabolism is that NNK generates a vast spectrum of DNA damage, any form of which can contribute to the overall carcinogenic properties of this potent pulmonary carcinogen. This Perspective reviews the chemistry and genotoxic properties of the collection of DNA adducts formed from NNK. In addition, it provides evidence that multiple adducts contribute to the overall carcinogenic properties of this chemical. The adduct that contributes to the genotoxic effects of NNK depends on the context, such as the relative amounts of each DNA alkylating pathway occurring in the model system, the levels and genetic variants of key repair enzymes, and the gene targeted for mutation.

Influence on radiosensitivity of lung glandular cancer cells when ERCC1 gene silenced by targeted siRNA

OBJECTIVE

To identify the influence on radiosensitivity of lung glandular cancer cells when excisions repair cross-complementing group1 (ERCC1) gene was silenced by targeted siRNA.

METHODS

siRNA which targeting to ERCC1 and control siRNA was designed and synthesized. The human lung glandular cancer SPC-A-1 cells was transfected. A total of 56 nude mice were divided into two groups, and two kinds of SPC-A-1 cells were transplanted to armpit of right forelimb, to establish the nude mice subcutaneous xenotransplanted tumor model of human lung glandular cancer cells. After the tumor was developed, the nude mice were randomly divided into four groups and accepted different doses of X-Ray radiation, then the change of tumor volume, survival time of mice in every group were recorded and the average lifetime was calculated. Twenty-one days later of X-ray experiment, two mice were taken and killed in each group and the tumors organizations were stripped. The cell apoptosis rate and cell cycle distributions were obtained by FCM (flow cytometry).

RESULTS

The volume of tumor which ERCC1 gene was silenced was less than single irradiation group after X-ray irradiation, and the growth speed was slower and the lifetime of mice was lengthened as well (P < 0.05). The cells apoptosis rate and the rate of G2/M cells which ERCC1 gene was silenced were higher than the same dose control group and the rate of G1 cells were lower, which indicated that the cells could be stopped at G2/M point, the cell proliferation was inhibited, the cell apoptosis was promoted and the radiation sensitivity was improved after the ERCC1 was silenced.

CONCLUSIONS

The radiation sensitivity of lung glandular tumor could be improved after the ERCC1 gene was silenced by siRNA.

Are male immigrants in Denmark at lower or higher risk of tobacco-related cancers? A Danish nationwide cohort study

BACKGROUND

Tobacco-related cancers (TRC) represent approximately a third of the cancer incidence in Denmark. However, tobacco consumption levels in immigrants may differ to the native population. We compared incidence rates of nine TRCs among male immigrants of first and second generation in Denmark with those among males of the native population.

MATERIAL AND METHODS

We used an established cohort of all Danish men (1978-2010) and calculated standardized incidence ratios (SIR) with 95% confidence intervals (CI) to compare incidence by immigration status and region of birth for nine TRCs.

RESULTS

We identified 131,317 incident cases of TRCs among 3,508,204 men (280,526 first generation and 129,056 second generation immigrants). Overall, immigrants of both generations experienced approximately 15% lower incidence of TRC than natives, however, with large variations by country of birth and type of TRC. Compared to natives, lung cancer incidence in first and second generation immigrants was 10% and 27% lower, respectively. However, lung cancer incidence increased in first generation immigrants reaching the level of native Danes in the late 2000s. First generation immigrants experienced approximately 50% lower incidence of lower urinary tract cancer than natives. However, only liver and stomach cancer had higher SIRs in immigrants.

CONCLUSION

Overall TRC incidence was lower among immigrants than in native Danes. Lower urinary tract cancer among first generation immigrants warrants further investigation.