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Asthma is a common heterogeneous disease with both genetic and environmental factors that affects millions of individuals worldwide. Activated type 2 helper T cells secrete a panel of cytokines, including IL-13, a central immune regulator of many of the hallmark type 2 disease characteristics found in asthma. IL-13 has been directly implicated as a potent stimulator of asthma induced airway remodeling. Although IL-13 is known to play a major role in the development and persistence of asthma, the complex combination of environmental and genetic origin of the disease obfuscate the solitary role of IL-13 in the disease. We therefore, used a genetically modified mouse model which conditionally overexpresses IL-13 in the lungs to study the independent role of IL-13 in the progression of asthma. Our results demonstrate IL-13 is associated with a systemic induction of genotoxic parameters such as oxidative DNA damage, single and double DNA strand breaks, micronucleus formation, and protein nitration. Furthermore we show that inflammation induced genotoxicity found in asthma extends beyond the primary site of the lung to circulating leukocytes and erythroblasts in the bone marrow eliciting systemic effects driven by IL-13 over-expression.

Cigarette smoke causes direct oxidative DNA damage as well as indirect damage through inflammation. Epidemiological studies show a strong relationship between secondhand smoke and cancer; however, the mechanisms of secondhand smoke-induced cancer are not well understood. Animal models with either (i) deficient oxidative DNA damage repair, or (ii) a decreased capacity to combat oxidative stress may help determine the pathways important in mitigating damage caused by smoke. In this study, we used mice lacking Ogg1 and Myh, both of which are involved in base excision repair by removing oxidatively damaged DNA bases. Gclm-deficient mice, which have decreased levels of glutathione (GSH), were used to look at the role of smoke-induced oxidative damage. Ex vivo experiments show significantly elevated levels of DNA single-strand breaks and chromosomal aberrations in peripheral blood lymphocytes from Ogg1(-/-)Myh(-/-) double knockout mice compared to wild type (WT) mice after 24h of exposure to cigarette smoke extract (CSE). The average γH2AX foci per cell was significantly elevated 3h after exposure to CSE in cells from Ogg1(-/-)Myh(-/-) double knockout mice compared to wildtype mice. In vivo we found that all mice had increased markers of DNA damage after exposure to side-stream tobacco smoke (SSTS). Ogg1(-/-)Myh(-/-) and Gclm(-/-) mice had altered levels of peripheral blood glutathione after SSTS exposure whereas wild type mice did not. This may be due to differential regulation of glutathione synthesis in the lung. We also found that Ogg1(-/-)Myh(-/-) mice had a decreased lifespan after oral gavage with benzo[a]pyrene compared to wildtype mice and sham-exposed Ogg1(-/-)Myh(-/-) mice. Our results are important in investigating the roles of oxidative stress and oxidative DNA damage repair in cigarette smoke-induced cancers and characterizing the role of genetic polymorphisms in smoke-related disease susceptibility.

Radiation and chemotherapy are effective treatments for cancer, but are also toxic to healthy cells. Little is known about whether prior exposure to these treatments is related to markers of cellular aging years later in breast cancer survivors. We examined whether past exposure to chemotherapy and/or radiation treatment was associated with DNA damage, telomerase activity, and telomere length 3–6 years after completion of primary treatments in breast cancer survivors (stage 0–IIIA breast cancer at diagnosis). We also examined the relationship of these cellular aging markers with plasma levels of Interleukin (IL)-6, soluble TNF-receptor-II (sTNF-RII), and C-reactive protein (CRP). Ninety-four women (36.4–69.5 years; 80% white) were evaluated. Analyses adjusting for age, race, BMI, and years from last treatment found that women who had prior exposure to chemotherapy and/or radiation compared to women who had previously received surgery alone were more likely to have higher levels of DNA damage (P = .02) and lower telomerase activity (P = .02), but did not have differences in telomere length. More DNA damage and lower telomerase were each associated with higher levels of sTNF-RII (P’s, Therapeutics: past chemotherapy and radiation linked to cellular aging Past exposure to chemotherapy and radiation is associated with signs of cellular aging among breast cancer survivors. Zorica Scuric, Judith Carroll, and colleagues from the University of California, Los Angeles, USA, tested markers of biological aging and inflammation in blood samples taken from women 3–6 years after their initial treatment for stage 0–IIIA breast cancer. They found that women who had received chemotherapy and/or radiation were more likely to have high levels of DNA damage, lower activity of telomerase—an enzyme involved in maintaining the length of chromosomes—and elevated inflammatory activation compared to women who underwent surgery alone. The findings point to an enduring biological effect of chemotherapy and radiation, and suggest that some breast cancer survivors may be vulnerable to accelerated aging because of their prior treatment.

Lung cancer is the leading cause of cancer-related mortality. While the majority of lung cancers are associated with tobacco smoke, approximately 10-15% of U.S. lung cancers occur in never smokers. Evidence suggests that lung cancer in never smokers appears to be a distinct disease caused by driver mutations which are different than the genetic pathways observed with lung cancer in smokers. A meta-analysis of human epidemiologic data was conducted to evaluate the profile of common or therapy-targetable mutations in lung cancers of never and ever smokers. Epidemiologic studies (N=167) representing over 63,000 lung cancer cases were identified and used to calculate summary odds ratios for lung cancer in never and ever smokers containing gene mutations: EGFR, chromosomal rearrangements and fusion of EML4 and ALK, and KRAS. This analysis also considered the effect of histopathology, smoking status, sex, and ethnicity. There were significantly increased odds of presenting the EGFR and ALK-EML4 mutations in 1) adenocarcinomas compared to non-small cell lung cancer and 2) never smokers compared to ever smokers. The prevalence of EGFR mutations was higher in Asian women as compared to women of Caucasian/Mixed ethnicity. As the smoking history increased, there was a decreased odds for exhibiting the EGFR mutation, particularly for cases >30 pack-years. Compared to ever smokers, never smokers had a decreased odds of KRAS mutations among those of Caucasian/Mixed ethnicity (OR=0.22, 95% CI: 0.17-0.29) and those of Asian ethnicity (OR=0.39, 95% CI: 0.30-0.50). Our findings show that key driver mutations and several patient features are highly prevalent in lung cancers of never smokers. These associations may be helpful as patient demographic models are developed to predict successful outcomes of targeted therapeutic interventions NSCLC.

A subset of patients with B cell malignancies does not respond to conventional current cytotoxic therapies. Novel immunotherapeutic approaches have been considered such as TRAIL and agonist DR4/DR5 mAbs that are currently in phase I/II clinical trials in patients with a variety of tumor types. However, most tumors are not sensitive to TRAIL/agonist antibodies due to the development of a generalized resistance to apoptotic stimuli. Therefore, for these therapies to be effective it is a requisite that resistance is modified by the use of sensitizing agents that target cell survival anti-apoptotic pathways or, more selectively, specific gene products in the apoptotic pathways. Proteasome inhibitors such as bortezomib and the novel inhibitor NPI-0052 have shown both direct cytotoxicity and also sensitizing ability when used in combination with biologics and cytotoxic drugs. We have recently reported that treatment of TRAIL-resistance B-NHL cell lines with NPI-0052 (not toxic by itself) in combination with TRAIL resulted in significant potentiation of apoptosis and synergy was achieved. Sensitization was due, in part, to inhibition of NF-kB activity and induction of Raf-1 kinase inhibitor protein (RKIP) [Baritaki et al., J Immunol 80:6199, 2008]. The role of RKIP in TRAIL apoptosis by NPI-0052 in Ramos cells was examined as well as the mechanism of NPI-0052-induced expression of RKIP. Like NPI-0052, overexpression of RKIP in Ramos cells sensitized the cells to TRAIL apoptosis and, in contrast, treatment with siRNA RKIP reversed this sensitizing effect. A recent report by our collaborators [Beach et al., Oncogene 27:2243,2008] demonstrated that RKIP transcription is negatively regulated, in part, by the metastasis-inducer transcription factor Snail. Thus, we hypothesized that NPI-0052-induced upregulation of RKIP may be due to inhibition of Snail. Indeed, treatment of Ramos cells with NPI-0052 significantly downregulated Snail expression concomitantly with upregulation of RKIP. Treatment of Ramos cells with siRNA Snail resulted in upregulation of RKIP and sensitization to TRAIL apoptosis. In contrast, ectopic expression of Snail repressed RKIP expression. Further, ectopic expression of RKIP inhibited Snail expression while siRNA RKIP upregulated Snail. These findings revealed the existence of a regulatory RKIP-NF-kB-Snail-RKIP loop. NPI-0052-induced inhibition of Snail also resulted in inhibition of Snail-induced gene products involved in metastasis. These findings demonstrate that NPI-0052 regulates B-NHL sensitivity to TRAIL apoptosis via the inhibition of Snail and induction of RKIP. These findings support the potential therapeutic application of the combination of NPI-0052 and TRAIL in the treatment of patients with resistant B-NHL and other malignancies.