Functional Genetic Screens Identify Genes Essential for Tumor Cell Survival in Head and Neck and Lung Cancer

Abstract

Purpose: Despite continuous improvement of treatment regimes, the mortality rates for non-small cell lung cancer (NSCLC) and head and neck squamous cell carcinoma (HNSCC) remain disappointingly high and novel anticancer agents are urgently awaited.Experimental Design: We combined the data from genome-wide siRNA screens on tumor cell lethality in a lung and a head and neck cancer cell line.Results: We identified 71 target genes that seem essential for the survival of both cancer types. We identified a cluster of 20 genes that play an important role during G 2 -M phase transition, underlining the importance of this cell-cycle checkpoint for tumor cell survival. Five genes from this cluster (CKAP5, KPNB1, RAN, TPX2, and KIF11) were evaluated in more detail and have been shown to be essential for tumor cell survival in both tumor types, but most particularly in HNSCC. Phenotypes that were observed following siRNA-mediated knockdown of KIF11 (kinesin family member 11) were reproduced by inhibition of KIF11 using the small-molecule inhibitor ispinesib (SB-715992). We showed that ispinesib induces a G 2 arrest, causes aberrant chromosome segregation, and induces cell death in HNSCC in vitro, whereas primary keratinocytes are less sensitive. Furthermore, growth of HNSCC cells engrafted in immunodeficient mice was significantly inhibited after ispinesib treatment.Conclusion: This study identified a wide array of druggable genes for both lung and head and neck cancer. In particular, multiple genes involved in the G 2 -M checkpoint were shown to be essential for tumor cell survival, indicating their potential as anticancer targets.

Genome-wide siRNA Screen Identifies the Radiosensitizing Effect of Downregulation of MASTL and FOXM1 in NSCLC

“…The SW1573 NSCLC cell line was subjected to a high-throughput forward transfection in 96-well plates as described before (9). Cells were seeded at a density of 200 cells per 96-well and were transfected 24 hours later.…”

TPX2 (TPX2, microtubule-associated, homolog (Xenopus laevis))

“…Two RNAi-based screenings identified TPX2 among essential genes for tumor survival and hence the most promising target candidates for anti-cancer strategies (Morgan-Lappe et al, 2007;Martens-de Kemp et al, 2013). Several studies provide direct demonstration of the antiproliferative effects of TPX2 inactivation in cancer cells of different tumor types (Morgan-Lappe et al, 2007;Zhang et al, 2008;Warner et al, 2009;Li et al, 2010;Satow et al, 2010;Chang et al, 2012;Vainio et TPX2 (TPX2, microtubule-associated, homolog (Xenopus laevis)) Asteriti IA, Guarguaglini G Atlas Genet Cytogenet Oncol Haematol.…”

“…Several studies provide direct demonstration of the antiproliferative effects of TPX2 inactivation in cancer cells of different tumor types (Morgan-Lappe et al, 2007;Zhang et al, 2008;Warner et al, 2009;Li et al, 2010;Satow et al, 2010;Chang et al, 2012;Vainio et TPX2 (TPX2, microtubule-associated, homolog (Xenopus laevis)) Asteriti IA, Guarguaglini G Atlas Genet Cytogenet Oncol Haematol. 2013;17(9) al., 2012; Martens-de Kemp et al, 2013). In addition, TPX2 inactivation significantly reduced tumor growth in xenografts models based on inoculation in nude mice of pancreatic or hepatocellular carcinoma cells (Warner et al, 2009;Satow et al, 2010).…”

AURKA mRNA expression is an independent predictor of poor prognosis in patients with non-small cell lung cancer

“…A number of mitotic spindle-associated proteins have been implicated in multiple malignancies, including lung cancer (5,6). Overexpression and gene amplification have been reported to contribute to the development and progression of malignant tumours for a number of mitotic spindle genes, including those involved in centrosome maturation [e.g., Aurora kinase (AURK)A, microtubule nucleation factor TPX2 (TPX2) and kinesin-like protein 11 (KIF11)] (7,8), microtubule formation [e.g., AURKA, cytoskeleton-associated protein 5 (CKAP5), tubulin β (TUBB) and TUBB3] (9-11), and chromosomal alignment and segregation [e.g., AURKA, AURKB, AURKC, discs large-associated protein 5 (DLGAP5) and TTK protein kinase (TTK)] (12)(13)(14).…”