The CXC chemokine interleukin‐8 (IL‐8) is an angiogenic growth factor that is overexpressed in various cancers, including non‐small cell lung cancer (NSCLC). Previously, IL‐8 was shown as a ...transcriptional target of RAS signaling, raising the possibility of its role in oncogenic KRAS‐driven NSCLC. Using microarray analysis, we identified IL‐8 as the most downregulated gene by shRNA‐mediated KRAS knockdown in NCI‐H1792 NSCLC cells where IL‐8 is overexpressed. NSCLC cell lines harboring KRAS or EGFR mutations overexpressed IL‐8, while IL‐8 levels were more prominent in KRAS mutants compared to EGFR mutants. IL‐8 expression was downregulated by shRNA‐mediated KRAS knockdown in KRAS mutants or by treatment with EGFR tyrosine kinase inhibitors and EGFR siRNAs in EGFR mutants. In our analysis of the relationship of IL‐8 expression with clinical parameters and mutation status of KRAS or EGFR in 89 NSCLC surgical specimens, IL‐8 expression was shown to be significantly higher in NSCLCs of males, smokers, and elderly patients and those with pleural involvement and KRAS mutated adenocarcinomas. In KRAS mutant cells, the MEK inhibitor markedly decreased IL‐8 expression, while the p38 inhibitor increased IL‐8 expression. Attenuation of IL‐8 function by siRNAs or a neutralizing antibody inhibited cell proliferation and migration of KRAS mutant/IL‐8 overexpressing NSCLC cells. These results indicate that activating mutations of KRAS or EGFR upregulate IL‐8 expression in NSCLC; IL‐8 is highly expressed in NSCLCs from males, smokers, elderly patients, NSCLCs with pleural involvement, and KRAS‐mutated adenocarcinomas; and IL‐8 plays a role in cell growth and migration in oncogenic KRAS‐driven NSCLC.
Small-cell lung cancer and other aggressive neuroendocrine cancers are often associated with early dissemination and frequent metastases. We demonstrate that neurogenic differentiation 1 (NeuroD1) is ...a regulatory hub securing cross talk among survival and migratory-inducing signaling pathways in neuroendocrine lung carcinomas. We find that NeuroD1 promotes tumor cell survival and metastasis in aggressive neuroendocrine lung tumors through regulation of the receptor tyrosine kinase tropomyosinrelated kinase B (TrkB). Like TrkB, the prometastatic signaling molecule neural cell adhesion molecule (NCAM) is a downstream target of NeuroD1, whose impaired expression mirrors loss of NeuroD1. TrkB and NCAM may be therapeutic targets for aggressive neuroendocrine cancers that express NeuroD1.
To identify potential therapeutic targets for lung cancer, we performed semi‐genome‐wide shRNA screening combined with the utilization of genome‐wide expression and copy number data. shRNA screening ...targeting 5043 genes in NCI‐H460 identified 51 genes as candidates. Pathway analysis revealed that the 51 genes were enriched for the five pathways, including ribosome, proteasome, RNA polymerase, pyrimidine metabolism and spliceosome pathways. We focused on the proteasome pathway that involved six candidate genes because its activation has been demonstrated in diverse human malignancies, including lung cancer. Microarray expression and array CGH data showed that PSMA6, a proteasomal subunit of a 20S catalytic core complex, was highly expressed in lung cancer cell lines, with recurrent gene amplifications in some cases. Therefore, we further examined the roles of PSMA6 in lung cancer. Silencing of PSMA6 induced apoptosis or G2/M cell cycle arrest in cancer cell lines but not in an immortalized normal lung cell line. These results suggested that PSMA6 serves as an attractive target with a high therapeutic index for lung cancer.
By doing an integrative analysis we have identified PSMA6, a subunit of the proteasome complex, as one of the most promising targets for lung cancer. We showed that PSMA6 knockdown suppressed the viability of cancer cells through the induction of apoptosis or cell cycle arrest at G2/M, with only a minimal effect on normal lung epithelial cells. Our data suggested that targeting PSMA6 for lung cancer may be an attractive novel therapeutic strategy.
Both pro‐ and anti‐oncogenic roles of miR‐221 and miR‐222 microRNAs are reported in several types of human cancers. A previous study suggested their oncogenic role in invasiveness in lung cancer, ...albeit only one cell line (H460) was used. To further evaluate involvement of miR‐221 and miR‐222 in lung cancer, we investigated the effects of miR‐221 and miR‐222 overexpression on six lung cancer cell lines, including H460, as well as one immortalized normal human bronchial epithelial cell line, HBEC4. miR‐221 and miR‐222 induced epithelial‐to‐mesenchymal transition (EMT)‐like changes in a minority of HBEC4 cells but, unexpectedly, both the microRNAs rather suppressed their invasiveness. Consistent with the prior report, miR‐221 and miR‐222 promoted growth in H460; however, miR‐221 suppressed growth in four other cell lines with no effects in one, and miR‐222 suppressed growth in three cell lines but promoted growth in two. These are the first results to show tumor‐suppressive effects of miR‐221 and miR‐222 in lung cancer cells, and we focused on clarifying the mechanisms. Cell cycle and apoptosis analyses revealed that growth suppression by miR‐221 and miR‐222 occurred through intra‐S‐phase arrest and/or apoptosis. Finally, lung cancer cell lines transfected with miR‐221 or miR‐222 became more sensitive to the S‐phase targeting drugs, possibly due to an increased S‐phase population. In conclusion, our data are the first to show tumor‐suppressive effects of miR‐221 and miR‐222 on lung cancer, warranting testing their potential as therapeutics for the disease.
Previous studies suggested oncogenic roles of miR‐221 and miR‐222 microRNAs in lung cancer, and thus they are believed to function solely as oncogenes in lung cancer. However, by analyzing multiple lung cancer cell lines with diverse genetic alterations, we here show that miR‐221 and miR‐222 function also as tumor suppressors, as demonstrated by their growth suppressive and chemosensitizing effects, warranting testing their potential as novel therapeutics for lung cancer.
Malignant pleural mesothelioma (MPM) is a highly aggressive neoplasm arising from the mesothelial cells lining the parietal pleura and it exhibits poor prognosis. Although there has been significant ...progress in MPM treatment, development of more efficient therapeutic approaches is needed. BMAL1 is a core component of the circadian clock machinery and its constitutive overexpression in MPM has been reported. Here, we demonstrate that BMAL1 may serve as a molecular target for MPM. The majority of MPM cell lines and a subset of MPM clinical specimens expressed higher levels of BMAL1 compared to a nontumorigenic mesothelial cell line (MeT‐5A) and normal parietal pleural specimens, respectively. A serum shock induced a rhythmical BMAL1 expression change in MeT‐5A but not in ACC‐MESO‐1, suggesting that the circadian rhythm pathway is deregulated in MPM cells. BMAL1 knockdown suppressed proliferation and anchorage‐dependent and independent clonal growth in two MPM cell lines (ACC‐MESO‐1 and H290) but not in MeT‐5A. Notably, BMAL1 depletion resulted in cell cycle disruption with a substantial increase in apoptotic and polyploidy cell population in association with downregulation of Wee1, cyclin B and p21WAF1/CIP1 and upregulation of cyclin E expression. BMAL1 knockdown induced mitotic catastrophe as denoted by disruption of cell cycle regulators and induction of drastic morphological changes including micronucleation and multiple nuclei in ACC‐MESO‐1 cells that expressed the highest level of BMAL1. Taken together, these findings indicate that BMAL1 has a critical role in MPM and could serve as an attractive therapeutic target for MPM.
Liposarcoma is a soft tissue neoplasm that commonly develops in the lower extremities and rarely in the head and neck region. Herein, we report the case of a patient with primary liposarcoma that was ...detected in the mastoid antrum during staged tympanoplasty for cholesteatoma. The tumor adjacent to the attic cholesteatoma was resected completely, and the pathological diagnosis was that of myxoid-type liposarcoma. Because positron emission tomography after the surgery showed no signs of tumor remnants or systemic metastasis, a second-stage surgery was performed 8 months after the first surgery. After confirming that there was no recurrence, tympanoplasty type III with interposition between the stapes and malleus and canal reconstruction was performed. No recurrence was observed for 5 years, and to date, good hearing has been maintained. This is the first report on long-term follow-up of a patient with liposarcoma in the mastoid antrum.
TIMELESS (TIM) is a mammalian homolog of a Drosophila circadian rhythm gene, but its circadian properties in mammals have yet to be determined. TIM appears to be essential for replication protection ...and genomic stability. Recently, the involvement of TIM in human malignancies has been reported; therefore, we investigated the role of TIM in lung cancer. Microarray expression analysis of lung cancer cell lines showed that TIM expression was elevated 3.7‐fold (P < 0.001) in non‐small cell lung cancer cell lines (n = 116) compared to normal lung controls (n = 59). In addition, small cell lung cancer cell lines (n = 29) expressed TIM at levels 2.2‐fold (P < 0.001) higher than non‐small cell lung cancer. Western blot analysis of 22 lung cancer cell lines revealed that all of them expressed TIM protein and that 20 cell lines (91%) expressed TIM protein at higher levels than a normal control line. Remarkably, immunohistochemistry of 30 surgically resected lung cancer specimens showed that all lung cancer specimens but no matched normal lung tissues were positive for TIM expression. Moreover, immunohistochemistry of surgically resected specimens from 88 consecutive patients showed that high TIM protein levels correlated with poor overall survival (P = 0.013). Mutation analysis for TIM in 23 lung cancer cell lines revealed no mutation. TIM knockdown suppressed proliferation and clonogenic growth, and induced apoptosis in H157 and H460 cells. Taken together, our findings suggest that TIM could be useful as a diagnostic and prognostic marker for lung cancer and targeting it would be of high therapeutic value for this disease.
Invasive tracheobronchial aspergillosis (ITBA), a rare form of invasive pulmonary Aspergillus infection (IPA), is predominantly confined to the tracheobronchial tree. We herein report a case of ITBA ...with severe necrotic pseudomembrane in a 57-year-old woman with fulminant hepatitis and hemophagocytic syndrome. Bronchoscopic findings revealed a widespread pseudomembranous formation of the trachea and bronchi. Aspergillus fumigatus was cultured from bronchial lavage fluid, and the histological findings of an endobronchial biopsy revealed necrosis and invasive hyphae. Although she responded to antifungal treatment, she ultimately died of a septic shock with Burkholderia cepacia 57 days after admission.
By expressing two genes (hTERT and Cdk4), we have developed a method to reproducibly generate continuously replicating human bronchial epithelial cell (HBEC) lines that provide a novel resource to ...study the molecular pathogenesis of lung cancer and the differentiation of bronchial epithelial cells. Twelve human bronchial epithelial biopsy specimens obtained from persons with and without lung cancer were placed into short-term culture and serially transfected with retroviral constructs containing cyclin-dependent kinase (Cdk) 4 and human telomerase reverse transcriptase (hTERT), resulting in continuously growing cultures. The order of introduction of Cdk4 and hTERT did not appear to be important; however, transfection of either gene alone did not result in immortalization. Although they could be cloned, the immortalized bronchial cells did not form colonies in soft agar or tumors in nude mice. The immortalized HBECs have epithelial morphology; express epithelial markers cytokeratins 7, 14, 17, and 19, the stem cell marker p63, and high levels of p16(INK4a); and have an intact p53 checkpoint pathway. Cytogenetic analysis and array comparative genomic hybridization profiling show immortalized HBECs to have duplication of parts of chromosomes 5 and 20. Microarray gene expression profiling demonstrates that the Cdk4/hTERT-immortalized bronchial cell lines clustered together and with nonimmortalized bronchial cells, distinct from lung cancer cell lines. We also immortalized several parental cultures with viral oncoproteins human papilloma virus type 16 E6/E7 with and without hTERT, and these cells exhibited loss of the p53 checkpoint and significantly different gene expression profiles compared with Cdk4/hTERT-immortalized HBECs. These HBEC lines are a valuable new tool for studying of the pathogenesis of lung cancer.
We evaluated the value of UHRF1, a regulator of methylation, as a biomarker for lung cancer. UHRF1 is expressed at higher levels in both lung adenocarcinoma (AD) and squamous cell carcinoma (SQ); ...however, a meta-analysis showed that UHRF1 expression is correlated with worse survival in patients with AD but not in those with SQ. UHRF1 knockdown suppressed the growth of lung cancer cell lines through G1 cell cycle arrest in some cell lines. These results suggest that UHRF1 may server as a diagnostic marker for AD and SQ and as a prognostic marker for AD in lung cancer.