thymosin-beta(4) and Carcinoma--Non-Small-Cell-Lung

Thymosin beta 4 (Tβ4), a pleiotropic actin-sequestering polypeptide that is involved in wound healing and developmental processes, has been reported to be strongly associated with tumorigenesis. A recent tissue microarray analysis showed that Tβ4 was highly expressed in certain tumor cells, including lung cancer. However, the exact expression pattern and the role of Tβ4 in non-small cell lung cancer (NSCLC) have not to our knowledge been investigated. In the present study, we confirmed that Tβ4 expression was increased in NSCLC tissues and cell lines. Tβ4 gene silencing in A549 and H1299 cells inhibited cell proliferation, migration, and invasion in vitro and decreased tumor growth in vivo Mechanistic investigations revealed a significant decrease in Notch1 activation in Tβ4 gene-silenced cells. Moreover, restoring the Notch1 expression attenuated the function of Tβ4 silencing in NSCLC cells. Taken together, these findings suggest that Tβ4 may play an oncogenic role in NSCLC progression and may be a novel molecular target for anti-NSCLC therapy.

Topics: A549 Cells; Animals; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Movement; Cell Proliferation; Gene Silencing; Humans; Lung Neoplasms; Mice; Mice, Nude; Neoplasm Invasiveness; Receptor, Notch1; Signal Transduction; Thymosin; Xenograft Model Antitumor Assays

Early-stage non-small cell lung cancer (NSCLC) can be cured by surgical resection, but a substantial fraction of patients ultimately dies due to distant metastasis. In this study, we used subtractive hybridization to identify gene expression differences in stage I NSCLC tumors that either did or did not metastasize in the course of disease. Individual clones (n=225) were sequenced and quantitative RT-PCR verified overexpression in metastasizing samples. Several of the identified genes (eIF4A1, thymosin beta4 and a novel transcript named MALAT-1) were demonstrated to be significantly associated with metastasis in NSCLC patients (n=70). The genes' association with metastasis was stage- and histology specific. The Kaplan-Meier analyses identified MALAT-1 and thymosin beta4 as prognostic parameters for patient survival in stage I NSCLC. The novel MALAT-1 transcript is a noncoding RNA of more than 8000 nt expressed from chromosome 11q13. It is highly expressed in lung, pancreas and other healthy organs as well as in NSCLC. MALAT-1 expressed sequences are conserved across several species indicating its potentially important function. Taken together, these data contribute to the identification of early-stage NSCLC patients that are at high risk to develop metastasis. The identification of MALAT-1 emphasizes the potential role of noncoding RNAs in human cancer.

Topics: Carcinoma, Non-Small-Cell Lung; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; In Situ Hybridization; Lung Neoplasms; Molecular Sequence Data; Neoplasm Metastasis; Neoplasm Staging; Predictive Value of Tests; Reference Values; Reverse Transcriptase Polymerase Chain Reaction; RNA, Untranslated; Survival Rate; Thymosin