Expression of miRNAs in non-small-cell lung carcinomas and their association with clinicopathological features.

Lung cancer is recognized as a leading cause of cancer-related deaths worldwide. Over the past several years, evidence emerged that microRNAs (miRNAs), a class of small non-coding RNA molecules regulating gene expression at posttranscriptional level, play an important role in cell functioning, as well as in human diseases. Here, we analyzed expression of miR-15a/16, miR-21, miR-34a, miR-126, miR-128, and miR-210 at transcriptional level in 30 non-small-cell lung carcinoma (NSCLC) tumor tissues compared to the matched adjacent normal tissues and their correlation with clinicopathological features of the patients. Samples were collected from the NSCLC patients undergoing surgery before radiotherapeutic or chemotherapeutic treatment. Expression levels of miRNAs were assessed by TaqMan RT-PCR assay. The data obtained in this study were processed using REST 2009 and SPSS statistical software. The graphs were designed by GraphPad prism 5.0. In tumor samples, we found downregulation of miR-15a/16 (50/83.3%), miR-34a (83.3%), miR-126 (70%), and miR-128 (63.3%). At the same time, miR-21 and miR-210 were upregulated by 53.3 and 66.6% in cancer tissue versus matched adjacent normal tissues, respectively. No significant correlation was found between the expression levels of miR-15a/16, miR-21, miR-34a, miR-126, miR-128, and miR-210 and lymph node, tumor size, sex, and smoking. However, the study demonstrated a correlation between a change in expression of miR-15, miR-16, miR-34a, miR-126, and miR-210 compared to normal tissues and TNM staging (P < 0.05). Furthermore, miR-126 expression level was different in adenocarcinomas and squamous cell carcinoma (SCC) subtype (P < 0.1). Detailed analysis revealed significant change in expression of miR-15a/16, miR-34a, miR-126, and miR-210 in NSCLC tumor samples indicating involvement of these miRNAs in lung cancer pathogenesis. miR-210 demonstrated the most consistent increase in tumor tissues between different patients, suggesting its potential significance for NSCLC.

Tumor suppressor protein kinase Chk2 is a mediator of anoikis of intestinal epithelial cells.

Resistance of carcinoma cells to anoikis, apoptosis that is normally induced by detachment of nonmalignant epithelial cells from the extracellular matrix, is thought to be critical for carcinoma progression. Molecular mechanisms that control anoikis of nonmalignant and cancer cells are understood poorly. In an effort to understand them we found that detachment of nonmalignant intestinal epithelial cells triggers upregulation of Chk2, a pro-apoptotic protein kinase that has never been implicated in anoikis and has been thought to kill cells mainly under the conditions compromising genome integrity. We found that enforced downregulation of Chk2 protects intestinal epithelial cells from anoikis. Chk2 can kill cells by stabilizing p53 tumor suppressor protein or via p53-independent mechanisms, and we established that Chk2-mediated anoikis of intestinal epithelial cells is p53-independent. We further found that, unlike nonmalignant intestinal epithelial cells whose anoikis is triggered by detachment-induced Chk2 upregulation, intestinal epithelial cells carrying oncogenic ras, a known inhibitor of anoikis, remain anoikis-resistant in response to enforced Chk2 upregulation. By contrast, drugs, such as topoisomerase I inhibitors, that can kill cells via Chk2-indpendent mechanisms, efficiently triggered anoikis of ras-transformed cells. Thus, oncogenic ras can prevent Chk2 from triggering anoikis even when levels of this protein kinase are elevated in cancer cells, and the use of therapeutic agents that kill cells in a Chk-2-independent, rather than Chk-2-dependent, manner could represent an efficient strategy for overcoming ras-induced anoikis resistance of these cells. We conclude that Chk-2 is an important novel component of anoikis-promoting machinery of intestinal epithelial cells.

Cell death in cancer therapy of lung adenocarcinoma.

Lung cancer is the main cause of all cancer-related deaths in the world, with lung adenocarcinoma (ADC) being the most common subtype of this fatal disease. Lung ADC is often diagnosed at advanced stages involving disseminated metastatic tumors. This is particularly important for the successful development of new cancer therapy approaches. The high resistance of lung ADC to conventional radio- and chemotherapies represents a major challenge to treatment effectiveness. Here we discuss recent progress in understanding the mechanisms of ADC's broad resistance to treatment and its possible therapeutic implications. A number of driving oncogenic alterations were identified in a subset of lung ADCs, making them suitable for targeted therapies directed towards specific cancer-associated molecular changes. In addition, we discuss the molecular aberrations common in lung ADC that are currently being exploited or are potentially important for targeted cancer therapy, as well as limitations of this type of therapy. Furthermore, we highlight possible treatment modalities that hold promise for overcoming resistance to targeted therapies as well as alternative treatment options such as immunotherapies that are potentially promising for improving the clinical outcome of lung ADC patients.

Tudor staphylococcal nuclease drives chemoresistance of non-small cell lung carcinoma cells by regulating S100A11.

Lung cancer is the leading cause of cancer-related deaths worldwide. Non-small cell lung cancer (NSCLC), the major lung cancer subtype, is characterized by high resistance to chemotherapy. Here we demonstrate that Tudor staphylococcal nuclease (SND1 or TSN) is overexpressed in NSCLC cell lines and tissues, and is important for maintaining NSCLC chemoresistance. Downregulation of TSN by RNAi in NSCLC cells led to strong potentiation of cell death in response to cisplatin. Silencing of TSN was accompanied by a significant decrease in S100A11 expression at both mRNA and protein level. Downregulation of S100A11 by RNAi resulted in enhanced sensitivity of NSCLC cells to cisplatin, oxaliplatin and 5-fluouracil. AACOCF(3), a phospholipase A(2) (PLA(2)) inhibitor, strongly abrogated chemosensitization upon silencing of S100A11 suggesting that PLA(2) inhibition by S100A11 governs the chemoresistance of NSCLC. Moreover, silencing of S100A11 stimulated mitochondrial superoxide production, which was decreased by AACOCF(3), as well as N-acetyl-L-cysteine, which also mimicked the effect of PLA(2) inhibitor on NSCLC chemosensitization upon S100A11 silencing. Thus, we present the novel TSN-S100A11-PLA(2) axis regulating superoxide-dependent apoptosis, triggered by platinum-based chemotherapeutic agents in NSCLC that may be targeted by innovative cancer therapies.

Upregulation of ATG3 contributes to autophagy induced by the detachment of intestinal epithelial cells from the extracellular matrix, but promotes autophagy-independent apoptosis of the attached cells.

Detachment of nonmalignant intestinal epithelial cells from the extracellular matrix (ECM) triggers their growth arrest and, ultimately, apoptosis. In contrast, colorectal cancer cells can grow without attachment to the ECM. This ability is critical for their malignant potential. We found previously that detachment-induced growth arrest of nonmalignant intestinal epithelial cells is driven by their detachment-triggered autophagy, and that RAS, a major oncogene, promotes growth of detached cells by blocking such autophagy. In an effort to identify the mechanisms of detachment-induced autophagy and growth arrest of nonmalignant cells we found here that detachment of these cells causes upregulation of ATG3 and that ATG3 upregulation contributes to autophagy and growth arrest of detached cells. We also observed that when ATG3 expression is artificially increased in the attached cells, ATG3 promotes neither autophagy nor growth arrest but triggers their apoptosis. ATG3 upregulation likely promotes autophagy of the detached but not that of the attached cells because detachment-dependent autophagy requires other detachment-induced events, such as the upregulation of ATG7. We further observed that those few adherent cells that do not die by apoptosis induced by ATG3 become resistant to apoptosis caused by cell detachment, a property that is critical for the ability of normal epithelial cells to become malignant. We conclude that cell-ECM adhesion can switch ATG3 functions: when upregulated in detached cells in the context of other autophagy-promoting events, ATG3 contributes to autophagy. However, when overexpressed in the adherent cells, in the circumstances not favoring autophagy, ATG3 triggers apoptosis.

miRNAs in lung cancer: a link to aging.

Lung cancer is a leading cause of cancer deaths worldwide. Development of lung cancer is associated with exposure to carcinogens such as tobacco smoke and some environmental factors. The incidence of lung cancer increases with age, particularly after age 60. It was estimated that less than 2% of all lung cancer cases occurred in patients younger than 45; therefore, this type of tumor can be considered as an aging-related disease. MicroRNAs (miRNAs) are small non-coding RNA molecules capable of regulating expression of over 50% of protein-coding genes. miRNAs were shown to play an extremely important role in cell functioning, affecting all biological processes, as well as development of various diseases. Expression profiles of miRNAs are known to be altered in cancer, including lung cancer, and also exhibit changes during aging. These RNA molecules are stable in tissue sections and blood and reflect tumor origin, histotype, and stage, which make them candidate diagnostic and prognostic biomarkers. miRNA mimetics or inhibitors can be delivered into a cell, with possible therapeutic implications. Here, we review the results obtained during the last several years that demonstrate the aging-related regulation of miRNAs expression, in association with their role in lung cancer initiation, progression, and resistance to anticancer therapy, as well as the possibility to use miRNAs as predictive biomarkers for treatment response.

Nitric oxide mediates distinct effects of various LPS chemotypes on phagocytosis and leukotriene synthesis in human neutrophils.

We investigated the effect of lipopolysaccharide (LPS) chemotypes differing in their carbohydrate chain length on phagocytosis of serum-opsonized zymosan (OZ) particles and related functions of human polymorphonuclear leukocyte (PMNL, neutrophils). LPS from deep core mutant (Re), complete core (Ra) and smooth (S) phenotypes of Salmonella typhimurium was studied. Priming of neutrophils with various LPSs caused prominent enhancement of OZ phagocytosis, superoxide production and leukotriene (LT) synthesis in neutrophils, with LPS effects increasing as Re