Abstract 4952: WWOX and LOT1 genes are down-regulated in non-small cell lung cancer (NSCLC)

Lung cancer is a result of uncontrolled cell growth in lung tissue and is the most common type of cancer leading to death in men and second after breast cancer in women. Even though smoking is the main reason of lung cancer, genetic and environmental factors play an important role in the onset and prognosis of the disease. The WW domain-containing oxidoreductase (WWOX) gene is a putative tumor suppressor gene located on chromosome 16q23.3-24.1 and is composed of 9 exons. Several studies have reported the role of WWOX gene in different types of carcinomas including lung, breast, ovarian, stomach and nasopharyngeal cancer. The 46kDa WWOX protein has two WW (tryptophan) domains which can recognize and bind the proline-rich region (PPXY) of other proteins. Its main function is to inhibit tumor cell growth. WWOX also plays an important role in wnt/beta-catenin signaling pathway. The lost-on-transformation 1 (LOT1/ZAC1/PLAGL1) gene is another putative tumor suppressor gene located on chromosome 6q24-25, a common site known for loss of heterozygosity in many tumors. Deletions of the 6q region are observed in different types of cancers including breast, prostate, small cell lung cancer and mesotheliomas. The LOT1 gene codes for a 55 kDa protein with seven C2H2 type zinc finger motifs located in amino terminal half of the protein. This zinc-finger nuclear transcription factor interacts with other proteins and transcription factors exerting antiproliferative effects in cancer cells. The aim of this study was to investigate the expression levels of the WWOX and LOT1 genes by RT-PCR in tumor tissue samples from 39 patients with non small cell lung cancer (NSCLC). We observed down-regulation of WWOX and LOT1 expression in 82.1% and 48.7% of the patients, respectively. Expression levels of both genes were down-regulated simultaneously in 18 (46.1%) of the patients. When we analyzed the association between gene expression and age, sex, smoking, histology and stage, we found that WWOX expression was decreased in 28 of 31 (90.3%) patients older than 50 years (p = 0.02). Lower expression levels of both genes supports the hypothesis that WWOX and LOT1 act as tumor suppressors in NSCLC and that both genes may have a common effect on tumor progression which warrants further studies to analyze a possible cooperation between the two proteins. Citation Format: Onur Baykara, Seda Ekizoglu Eratak, Kamil Kaynak, Hikmet Koseoglu, Nur Buyru. WWOX and LOT1 genes are down-regulated in non-small cell lung cancer (NSCLC). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4952. doi:10.1158/1538-7445.AM2015-4952