Paxillin Is a Target for Somatic Mutations in Lung Cancer: Implications for Cell Growth and Invasion

Abstract

Lung cancer is characterized by abnormal cell growth and invasion, and the actin cytoskeleton plays a major role in these processes. The focal adhesion protein paxillin is a target of a number of oncogenes involved in key signal transduction and important in cell motility and migration. In lung cancer tissues, we have found that paxillin was highly expressed (compared with normal lung), amplified (12.1%, 8 of 66) and correlated with increased MET and epidermal growth factor receptor (EGFR) gene copy numbers, or mutated (somatic mutation rate of 9.4%, 18 of 191). Paxillin mutations (19 of 21) were clustered between LD motifs 1 and 2 and the LIM domains. The most frequent point mutation (A127T) enhanced lung cancer cell growth, colony formation, focal adhesion formation, and colocalized with Bcl-2 in vitro. Gene silencing from RNA interference of mutant paxillin led to reduction of cell viability. A murine in vivo xenograft model of A127T paxillin showed an increase in tumor growth, cell proliferation, and invasion. These results establish an important role for paxillin in lung cancer. [Cancer Res 2008;68(1):132-42]

Bcl-2 stabilization by paxillin confers 5-fluorouracil resistance in colorectal cancer

“…The PXN-GFP overexpression plasmid constructed into pAcGFP1-N1 vector was kindly provided by Dr. Salgia (The University of Chicago, Chicago, IL, USA). 32 Mutant PXN-GFP (tyrosine 31/118 changed to phenylalanine: Y31/118F, serine 272 changed to alanine: S272A and LD4 domain deletion: ΔLD4) and Bcl-2-Flag (serine 87 changed to alanine: S87A and serine 87 changed to glutamic acid: S87E) expression constructs containing multiple-point mutations were constructed by the QuickChange site-directed mutagenesis system (Stratagene, La Jolla, CA, USA). The Bcl-2-Flag overexpression plasmid constructed into pCMV-Tag2B vector was purchased from Addgene (Addgene Company, Cambridge, MA, USA).…”

RON(MST1R)is a novel prognostic marker and therapeutic target for gastroesophageal adenocarcinoma

“…78 Descriptive patterns such as extensity of tumor (e.g., diffuse versus patchy/focal), cellular localization Immunoblotting. Cell lysate preparation, SDS-PAGE and immunoblot analysis was performed as previously described in references 61 and 78.…”

Somatic LMCD1 mutations promoted cell migration and tumor metastasis in hepatocellular carcinoma

“…Interestingly, by incorporating a 3p amplified region from the thyroid carcinoma CAL62 cell line (ICN ¼ 3.46), we narrowed down and defined a 2.53-Mb amplicon at 3p26.1-25.3 (Figure 1a). Among 8 known and 6 predicted genes residing in this region, LMCD1 was chosen as a candidate cancer gene based on the following three reasons: (1) LMCD1 is located at the amplification peak of overlapped amplicons in SNU387 and Hep3B cells; (2) several LIM domain-containing proteins have been shown to be relevant to tumor progression (Bagheri-Yarmand et al, 2006;Jagadeeswaran et al, 2008) and (3) LMCD1 is commonly overexpressed in HCC tissues based on in silico analysis of HCC data sets from the iCOD database (61 of 129, log 2 T/N 40.5), with a significantly higher average LMCD1/GAPDH level in HCCs than in normal references (Po0.001 by two-sample t-test) (Figure 1b). The upregulated LMCD1 was further validated in these three HCC cell lines, HA22T, Hep3B and SNU387, and eight pairs of HCC tissues by semi-quantitative reverse transcription-PCR assay (Figure 1c).…”