Chromosomal alterations, biological features and in vitro chemosensitivity of SCLC-R1, a new cell line from human metastatic small cell lung carcinoma

Caveolin-1 silencing arrests the proliferation of metastatic lung cancer cells through the inhibition of STAT3 signaling

Cav-1 is an essential structural constituent of caveolae implicated in mitogenic signaling, oncogenesis, angiogenesis, neurodegenerative diseases and senescence. Its role as a tumor suppressor gene or as a tumor promoter seems to strictly depend on cell type and tumor stage/grade. The high expression of Cav-1 in some tumors in vivo, amongst which lung adenocarcinoma, is associated with increased tumor aggressiveness, metastatic potential and suppression of apoptosis. In the present study we investigated the role of Cav-1 in metastatic lung cancer proliferation. Cell lines were from metastatic lesions of lung adenocarcinoma (RAL) and of small cell lung carcinoma (SCLC-R1), in which we found Cav-1 expressed at high levels. Results show that siRNA-mediated down-regulation of Cav-1 caused stable arrest of proliferation in both cell lines. A marked reduction of cyclin D1 and of CDK4 expression was evident in the cells transfected with Cav-1 siRNA and consequently of phospho-Rb on ser(795) and ser(780). Furthermore, a significant decrease of the expression of phosphorylated AKT and of its down-stream effectors phosphorylated ERK and STAT3 was evident. Together, these findings indicate that Cav-1 silencing induces an arrest of human metastatic lung proliferation in vitro by a new inhibitory pathway in lung cancer and provide new insights into the molecular mechanisms underlying the pro-survival and tumor-promoting functions of Cav-1.

Pharmacogenetics of anticancer drug sensitivity in non-small cell lung cancer

In mammalian cells, the process of malignant transformation is characterized by the loss or down-regulation of tumor-suppressor genes and/or the mutation or overexpression of proto-oncogenes, whose products promote dysregulated proliferation of cells and extend their life span. Deregulation in intracellular transduction pathways generates mitogenic signals that promote abnormal cell growth and the acquisition of an undifferentiated phenotype. Genetic abnormalities in cancer have been widely studied to identify those factors predictive of tumor progression, survival, and response to chemotherapeutic agents. Pharmacogenetics has been founded as a science to examine the genetic basis of interindividual variation in drug metabolism, drug targets, and transporters, which result in differences in the efficacy and safety of many therapeutic agents. The traditional pharmacogenetic approach relies on studying sequence variations in candidate genes suspected of affecting drug response. However, these studies have yielded contradictory results because of the small number of molecular determinants of drug response examined, and in several cases this approach was revealed to be reductionistic. This limitation is now being overcome by the use of novel techniques, i.e., high-density DNA and protein arrays, which allow genome- and proteome-wide tumor profiling. Pharmacogenomics represents the natural evolution of pharmacogenetics since it addresses, on a genome-wide basis, the effect of the sum of genetic variants on drug responses of individuals. Development of pharmacogenomics as a new field has accelerated the progress in drug discovery by the identification of novel therapeutic targets by expression profiling at the genomic or proteomic levels. In addition to this, pharmacogenetics and pharmacogenomics provide an important opportunity to select patients who may benefit from the administration of specific agents that best match the genetic profile of the disease, thus allowing maximum activity.