Correction to: BRG1 regulation by miR-155 in human leukemia and lymphoma cell lines.

Following the publication of the original article the author listed as Antonio Herrera contacted the Publisher to state that his correct and full name is Antonio Herrera-Merchan. Antonio Herrera-Merchan has agreed to the publication of this erratum.

BRG1 regulation by miR-155 in human leukemia and lymphoma cell lines.

INTRODUCTION/PURPOSE: BRG1 is a key regulator of leukemia stem cells. Indeed, it has been observed that this type of cells is unable to divide, survive and develop new tumors when BRG1 is down-regulated. MATERIALS AND METHODS: We assessed BRG1 and miR-155 expression in 23 leukemia cell lines, and two no pathological lymphocyte samples using qPCR. MiR-155 transfection and western blot were used to analyze the relationship between miR-155 and its validated target, BRG1, by measuring protein expression levels. The effect of miR-155 on cell proliferation and prednisolone sensitivity were studied with resazurin assay. RESULTS: BRG1 expression levels could correlate negatively with miR-155 expression levels, at least in Burkitt's lymphoma and diffuse large B cell lymphoma (DLBCL) cell lines. To clarify the role of miR-155 in the regulation of BRG1 expression, we administrated miR-155 mimics in different leukemia/lymphoma cell lines. Our results suggest that miR-155 regulate negatively and significantly the BRG1 expression at least in the MOLT4 cell line. CONCLUSION: Our study revealed a previously unknown miR-155 heterogeneity that could result in differences in the treatment with miRNAs in our attempt to inhibit BRG1. However, the expression levels of BRG1 and miR-155, before prednisolone treatment were not statistically significantly associated prednisolone sensitive leukemia cells.

Regression of murine lung tumors by the let-7 microRNA.

MicroRNAs (miRNAs) have recently emerged as an important new class of cellular regulators that control various cellular processes and are implicated in human diseases, including cancer. Here, we show that loss of let-7 function enhances lung tumor formation in vivo, strongly supporting the hypothesis that let-7 is a tumor suppressor. Moreover, we report that exogenous delivery of let-7 to established tumors in mouse models of non-small-cell lung cancer (NSCLC) significantly reduces the tumor burden. These results demonstrate the therapeutic potential of let-7 in NSCLC and point to miRNA replacement therapy as a promising approach in cancer treatment.

Expression signatures in lung cancer reveal a profile for EGFR-mutant tumours and identify selective PIK3CA overexpression by gene amplification.

The development of targeted therapies creates a need to discriminate tumours accurately by their histological and genetic characteristics. Here, we aim to identify gene expression profiles and single markers that recapitulate the pathological and genetic background of non-small cell lung cancer (NSCLC). We performed cDNA microarray analysis on a series of 69 NSCLCs, with known mutation status for important genes, and six normal lung tissues. Unsupervised cluster analysis segregated normal lungs from lung tumours and lung tumours according to their histopathology and the presence of EGFR mutations. Several transcripts were highly overexpressed (by approximately 20 times) in squamous cell carcinomas (SCCs) relative to adenocarcinomas (ACs) and confirmed by immunohistochemistry in an independent cohort of 75 lung tumours. Expression of 13 genes constituted the most prominent hallmarks of EGFR-mutant tumours, including increased levels of proline dehydrogenase (PRODH) and down-regulation of X-box binding protein 1 (XBP1). No genes were differentially expressed, with a fold change >or= 4 or

Dysfunctional AMPK activity, signalling through mTOR and survival in response to energetic stress in LKB1-deficient lung cancer.

LKB1, mutated in Peutz-Jeghers and in sporadic lung tumours, phosphorylates a group of protein kinases named AMP-activated protein kinase (AMPK)-related kinases. Among them is included the AMPK, a sensor of cellular energy status. To investigate the relevance of LKB1 in lung carcinogenesis, we study several lung cancer cells with and without LKB1-inactivating mutations. We report that LKB1-mutant cells are deficient for AMPK activity and refractory to mTOR inhibition upon glucose depletion but not growth-factor deprivation. The requirement for wild-type LKB1 to properly activate AMPK is further demonstrated in genetically modified cancer cells. In addition, LKB1-deficient lung primary tumours had diminished AMPK activity, assessed by complete absence or low level of phosphorylation of its critical substrate, acetyl-CoA carboxylase. We also demonstrate that LKB1 wild-type cells are more resistant to cell death upon glucose withdrawal than their mutant counterparts. Finally, modulation of AMPK activity did not affect PI3K/AKT signalling, an advantage for the potential use of AMPK as a target for cancer therapy in LKB1 wild-type tumours. Thus, sustained abrogation of cell energetic checkpoint control, through alterations at key genes, appear to be an obligatory step in the development of some lung tumours.