Investigate the role of regulator of chromosome condensation 2 () on lung adenocarcinoma (LUAD) metastasis. Clinical specimens were used to assess the impact of RCC2 on LUAD metastasis. Mouse models, cytobiology, and molecular biology assays were performed to elucidate the function and underlying mechanisms of RCC2 in LUAD. RCC2 expression was frequently increased in LUADs (88/122, 72.13%). It was confirmed by analysis of a larger cohort of TCGA RNA-seq data containing 488 LUADs and 58 normal lung tissues ( < 0.001). Importantly, increased level of RCC2 was significantly associated with T status of tumor ( = 0.002), lymph node metastasis ( = 0.004), and advanced clinical stage ( = 0.001). Patients with LUAD with higher expression of RCC2 had shorter overall survival. Cox regression analysis demonstrated that RCC2 was an independent poorer prognostic factor for patients with LUAD. Moreover, forced expression of RCC2 promoted intrapulmonary metastasis and significantly enhanced LUAD cell migration, invasion, and proliferation Further study found that RCC2 induced epithelial-mesenchymal transition (EMT) and also stimulated the expression of MMP-2 and MMP-9. In addition, RCC2 was able to activate JNK, while inhibition of JNK suppressed the effect of RCC2 on LUAD cell migration, invasion, EMT, and the expression of MMP-2 and MMP-9. RCC2 plays a pivotal role in LUAD metastasis by inducing EMT via activation of MAPK-JNK signaling. .

Double minute chromosomes are cytogenetic manifestations of gene amplification frequently seen in cancer cells. Genes amplified on double minute chromosomes include oncogenes and multi-drug resistant genes. These genes encode proteins which contribute to cancer formation, cancer progression, and development of resistance to drugs used in cancer treatment. Elimination of double minute chromosomes, and therefore genes amplified on them, is an effective way to decrease the malignancy of cancer cells. We investigated the effectiveness of a cancer drug, gemcitabine, on the loss of double minute chromosomes from the ovarian cancer cell line UACC-1598. Gemcitabine is able to decrease the number of double minute chromosomes in cells at a 7500X lower concentration than the commonly used cancer drug hydroxyurea. Amplified genes present on the double minute chromosomes are decreased at the DNA level upon gemcitabine treatment. Gemcitabine, even at a low nanomolar concentration, is able to cause DNA damage. The selective incorporation of double minutes chromatin and γ-H2AX signals into micronuclei provides a strong link between DNA damage and the loss of double minute chromosomes from gemcitabine treated cells. Cells treated with gemcitabine also showed decreased cell growth, colony formation, and invasion. Together, our results suggest that gemcitabine is effective in decreasing double minute chromosomes and this affects the biology of ovarian cancer cells.

Gene amplification, which involves the two major topographical structures double minutes (DMs) and homegeneously stained region (HSR), is a common mechanism of treatment resistance in cancer and is initiated by DNA double-strand breaks. NHEJ, one of DSB repair pathways, is involved in gene amplification as we demonstrated previously. However, the involvement of homologous recombination, another DSB repair pathway, in gene amplification remains to be explored. To better understand the association between HR and gene amplification, we detected HR activity in DM- and HSR-containing MTX-resistant HT-29 colon cancer cells. In DM-containing MTX-resistant cells, we found increased homologous recombination activity compared with that in MTX-sensitive cells. Therefore, we suppressed HR activity by silencing BRCA1, the key player in the HR pathway. The attenuation of HR activity decreased the numbers of DMs and DM-form amplified gene copies and increased the exclusion of micronuclei and nuclear buds that contained DM-form amplification; these changes were accompanied by cell cycle acceleration and increased MTX sensitivity. In contrast, BRCA1 silencing did not influence the number of amplified genes and MTX sensitivity in HSR-containing MTX-resistant cells. In conclusion, our results suggest that the HR pathway plays different roles in extrachromosomal and intrachromosomal gene amplification and may be a new target to improve chemotherapeutic outcome by decreasing extrachromosomal amplification in cancer.

Double minute chromosomes (DMs) are a hallmark of gene amplification. The relationship between the formation of DMs and the amplification of DM-carried genes remains to be clarified. The human colorectal cancer cell line NCI-H716 and human malignant primitive neuroectodermal tumor cell line SK-PN-DW are known to contain many DMs. To examine the amplification of DM-carried genes in tumor cells, we performed Affymetrix SNP Array 6.0 analyses and verified the regions of amplification in NCI-H716 and SK-PN-DW tumor cells. We identified the amplification regions and the DM-carried genes that were amplified and overexpressed in tumor cells. Using RNA interference, we downregulated seven DM-carried genes, (NDUFB9, MTSS1, NSMCE2, TRIB1, FAM84B, MYC and FGFR2) individually and then investigated the formation of DMs, the amplification of the DM-carried genes, DNA damage and the physiological function of these genes. We found that suppressing the expression of DM-carried genes led to a decrease in the number of DMs and reduced the amplification of the DM-carried genes through the micronuclei expulsion of DMs from the tumor cells. We further detected an increase in the number of γH2AX foci in the knockdown cells, which provides a strong link between DNA damage and the loss of DMs. In addition, the loss of DMs and the reduced amplification and expression of the DM-carried genes resulted in a decrease in cell proliferation and invasion ability.

The obesity-asthma phenotype is characterized by increased asthma severity and decreased glucocorticoid responsiveness. To date, the mechanism underlying the association between obesity and asthma remain to be fully elucidated. The present study investigated the correlation between oxidative stress and the nuclear factor (NF)-κB pathway in obese asthmatic mice. The animals were divided into the following groups: Control (n=8), comprising C57BL/6J mice without exposure to a high-fat diet; non-obese asthma group (n=8), comprising mice of a normal weight subjected to the induction of asthma; obese control group (n=8), comprising C57BL/6J mice subjected to a high-fat diet; and obese asthmatic group (n=8), comprising obese mice subject to the induction of asthma. The levels of the malondialdehyde (MDA) oxidant and glutathione (GSH) antioxidant in the lungs and bronchoalveolar lavage fluid (BALF) were measured using ELISA. The expression levels of inhibitory κB kinase-β (IKK-β) and the inhibitor of κBα (IκB-α) in the pulmonary tissues was determined using western blot analysis. An electrophoretic mobility shift assay was performed to determine the transcription activity of NF-κB. The levels of MDA in the BALF and lung tissues increased significantly in the two asthmatic groups, compared with the control groups (P<0.01). The asthmatic mice showed significantly lower concentrations of GSH in the BALF and lung tissues, compared with the control groups (P<0.01). In the asthmatic animals, the expression of IκB kinase (IKK)-β and activation of NF-κB were upregulated in the pulmonary tissues, compared with those in the control groups (P<0.01). The expression of IKK-β and transcriptional activity of NF-κB were significantly higher the in obese asthmatic mice, compared with the non-obese asthmatic mice (P<0.01). On examining the expression levels of IκB-α in the pulmonary tissues, a significant reduction was found in the asthmatic animals, compared with the controls (P<0.01). In addition, the level of IκB-α was significantly lower in the obese asthmatics, compared with the non-obese asthmatics (P<0.01). MDA was positively correlated with NF-κB in the obese asthmatic group (R=0.83; P<0.05) and non-obese asthmatic group (R=0.82; P<0.05). Oxidative stress was upregulated in the pulmonary tissues of the asthmatic mice. This upregulation was more marked in the obese asthmatic mice, and was positively correlated with activation of the NF-κB signaling pathway in the pulmonary tissues. The results in the present study indicated that higher oxidative stress and activation of the NF-κB signaling pathway were observed in the lung tissues of the obese asthmatics. Furthermore, a positive correlation was identified between oxidative stress and NF-κB.

The findings indicate that the LCE3C_LCE3B-del is an important risk factor in the pathogenesis of psoriasis and that the LCE3C_LCE3B-del does not show an epistatic effect with the HLA-Cw6 allele on susceptibility to psoriasis in the northern Chinese population.

Double minutes (DMs) are hallmarks of gene amplification. However, their molecular structure and the mechanisms of formation are largely unknown. To elucidate the structure and underlying molecular mechanism of DMs, we obtained and cloned DMs using microdissection; and degenerated oligonucleotide primed polymerase chain reaction (DOP-PCR) from the ovarian cancer cell line UACC-1598. Two large amplicons, the 284 kb AmpMYCN, originating from locus 2p24.3 and the 391 kb AmpEIF5A2, from locus 3q26.2, were found co-amplified on the same DMs. The two amplicons are joined through a complex 7 kb junction DNA sequence. Analysis of the junction has revealed three de novo created small palindromes surrounding the six breakpoints. Consistent with these observations, we further found that 70% of the 57 reported DM junction sequences have de novo creation of small palindromic sequences surrounding the breakpoints. Together, our findings indicate that de novo-generated small palindromic sequences are characteristic of amplicon boundary junctions on DMs. It is possible that the de novo-generated small palindromic sequences, which may be generated through non-homologous end joining in concert with a novel DNA repair machinery, play a common role in amplicon rejoining and gene amplification.

Human non-small cell lung cancer (NSCLC) is one of the most common malignancies in the modern world. Its recurrence is mainly due to its ability to invade and metastasize. However, the precise mechanism for tumor development and metastasis is still not fully understood. To shed light on the development of lung cancer, the human giant cell lung carcinoma cell lines 95D with high metastatic potential and 95C with low metastatic potential were selected in this study. The 2 cell lines originated from the same parental cell and share a similar genetic background. In the current study, we identified 3 differentially expressed proteins in 95C and 95D cell lines, namely, PAI-RBP1, C1orf142, and COTL1, by using 2-dimensional electrophoresis proteomics analysis. We found that PAI-RBP1 and C1orf142 expression levels were higher in 95D than in 95C cells, whereas COTL1 expression level was lower in 95D when compared to 95C cells. We also confirmed these results by reverse transcription-polymerase chain reaction and immunoblotting analyses. The messenger RNA and protein levels of PAI-RBP1 and C1orf142 were much higher in 95D than in 95C cells, and COTL1 expression level was lower in 95D than in 95C cells. The PAI-RBP1 expression was assessed by immunohistochemistry in 70 NSCLC and 7 normal lung tissue samples from patients. PAI-RBP1 expression level was higher in tumor tissues (positive staining in 87.1% of cases [61/70]) than in normal tissues (positive staining in 14.3% of cases [1/7]). In conclusion, by studying protein expression in NSCLC cell lines with high and low metastasis as well as in human lung cancer tissues, we have identified 3 proteins, namely, PAI-RBP1, C1orf142, and COTL1, which were differentially expressed in NSCLC cell lines with different metastatic potential. In addition, we also found that PAI-RBP1 might contribute to NSCLC development.