Metastasis is a major obstacle that must be overcome for the successful treatment of lung cancer. Proteins secreted by cancer cells may facilitate the progression of metastasis, particularly within the phases of migration and invasion. To discover metastasis-promoting secretory proteins within cancer cells, we used the label-free quantitative proteomics approach and compared the secretomes from the lung adenocarcinoma cell lines CL1-0 and CL1-5, which exhibit low and high metastatic properties, respectively. By employing quantitative analyses, we identified 660 proteins, 68 of which were considered to be expressed at different levels between the two cell lines. Lung cancer is the leading cause of cancer death, and ϳ90% of all lung cancer deaths are attributed to metastases (1). Approximately 95% of lung cancer patients are not diagnosed until they develop symptoms, and 85% of the newly diagnosed lung cancer patients are already in the advanced stages of the disease (2, 3). Once the tumor cells have metastasized and spread throughout the lungs, the cancer is considerably more difficult to treat. Invasiveness and metastasis are major threats to successful treatment. Cancer metastasis is an intricate, multi-step process in which the tumor cells must gain both migratory and invasive properties (4). In metastasis research, there are two common in vivo models, spontaneous and experimental metastasis (5-7). In brief, spontaneous metastasis refers to primary tumor cells that are able to dissociate from the primary tumor and metastasize to the secondary organ via the circulatory system. In contrast, experimental metastasis refers to the injection of tumor cells directly into the systemic circulation. Many researchers have attempted to determine the molecular basis of these transitions in hopes of developing target-specific drugs or biomarkers for the prevention and diagnosis of metastasis. Although there have been many discoveries regarding a particular proFrom the ‡Department

BCOR-CCNB3-positive sarcomas may primarily occur in soft tissues of adults and show PDSS-mimicking round-cell and spindle-cell histology with aggressive behaviour. Cyclin B3 is useful for selecting candidates for BCOR-CCNB3 molecular testing.

Skin and soft-tissue infections (SSTIs) caused by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) have emerged as major health problems throughout the world. Most SSTI CA-MRSA strains produce Panton-Valentine leukocidin (PVL), but its contribution to CA-MRSA pathogenesis is poorly defined. Here, we used an endemic PVL-positive SSTI-causing CA-MRSA strain from Taiwan, together with an isogenic PVL-knockout mutant (Δpvl) and complemented PVL-positive derivative, to evaluate the role of PVL in the pathogenesis of CA-MRSA in the RHEK-1 human keratinocyte cell line and a rabbit skin infection model. We found that both PVL-positive CA-MRSA and isogenic Δpvl strains attached and were engulfed into endosomes of RHEK-1 cells within 1 hour following infection. However, by 2 hours after infection PVL-positive CA-MRSA more effectively disrupted endosomes, escaped into the cytoplasm, and replicated intracellularly. By 6 hours after infection, the PVL-positive strain caused significantly more caspase-dependent keratinocyte apoptosis than the isogenic Δpvl mutant. In the rabbit infection model, 1 week following infection the wild-type strain produced significantly more widespread lesions and cell apoptosis than the isogenic Δpvl mutant. These findings indicate that PVL is an important virulence factor that enables CA-MRSA to produce necrotizing skin infections by allowing the bacteria to escape from endosomes, replicate intracellularly, and induce apoptosis.

Growing evidence suggests that Stat3 contributes to chemoresistance. However, the impact of chemotherapy on Stat3 activity is unclear. We found that paclitaxel activated Stat3 in the human lung cancer cell lines PC14PE6AS2 (AS2) and H157, whereas it reduced Stat3 activation in A549 and H460 cells. Pretreatment of AS2 and H157 cells with rotenone, an inhibitor of mitochondrially produced reactive oxygen species (ROS), or carbonyl cyanide p-(trifluoromethoxy)-phenylhydrazone (FCCP), a mitochondrial uncoupler, suppressed the paclitaxel-induced activation of Stat3. Uncoupling protein 2 (UCP-2), located in the inner membrane of the mitochondria, can reduce ROS production in conditions of oxidative stress. UCP-2 protein expression in the four cancer cell lines was higher than that in normal lung epithelial cells (NL-20), but its expression was lower in AS2 and H157 cells relative to A549 and H460 cells. Silencing high UCP-2 expression with small interfering RNA (siRNA) in A549 and H460 cells restored paclitaxel-induced Stat3 activation. In addition, paclitaxel-induced Stat3 activation led to the upregulation of survivin and Mcl-1, which in turn facilitated cell survival. Moreover, the CL1-5 subline had lower UCP-2 expression relative to the parental CL1-0 cells. Treatment with paclitaxel activated Stat3 in CL1-5 but not in CL1-0 cells, whereas in CL1-5 cells, the overexpression of UCP-2 with complementary DNA (cDNA) blocked Stat3 activation. In lung cancer patients, low UCP-2 expression in cancer cells was a predictor of a poor response to chemotherapy. Therefore, UCP-2 modulates the ROS/Stat3 signaling pathway and response to chemotherapy treatment in lung cancer cells. Targeting UCP-2, ROS and Stat3 pathways may improve anticancer therapies.

mutated cases were reclassified as spindle embryonal (n = 3), dense embryonal (n = 1) and unclassifiable (n = 1) RMSs. Conclusion: MYOD1-mutant RMSs are uncommonly mutated with PIK3CA and behave aggressively with an expanded morphological and genetic spectrum, including lipoblastic differentiation, multinucleated cells and the alternative p.E118K mutation.