OBJECTIVE: The inhibition of epidermal growth factor receptor (EGFr) with the monoclonal antibody cetuximab reduces cell proliferation and survival which correlates with increased DNA damage. Since the signal transducer and activator of transcription-3 (STAT-3) is involved in the EGFr-induced signaling pathway, we hypothesized that depletion of STAT-3 may augment cetuximab-induced processes in human head and neck cancer cells. MATERIALS AND METHODS: Human head and neck squamous carcinoma cells (UM-SCC-5) were transfected with short hairpin RNA (shRNA) against STAT-3 (STAT3-2.4 and 2.9 cells). A mutated form of this shRNA was transfected for a control (NEG4.17 cells). Radiosensitivity was assessed by a standard colony formation assay. Proliferation was assessed by daily cell counts following treatment and apoptosis was assessed by an annexin V-FITC assay. The alkaline comet assay was used to assess DNA damage. RESULTS: The STAT-3 knockdown cells (STAT3-2.4 and STAT3-2.9 cells) demonstrated enhanced radiosensitivity compared to control NEG4.17 cells, which correlated with increased apoptosis. Also, the STAT-3 knockdown cells demonstrated decreased proliferation with cetuximab treatments compared to control cells (NEG4.17). The increased cetuximab sensitivity of the STAT-3 knockdown cells correlated with increased apoptosis and DNA damage compared to control cells (NEG4.17). CONCLUSION: These studies revealed that the greater anti-proliferative effects and increased cytotoxicity of cetuximab in the STAT3-2.4 and STAT3-2.9 cells compared to control NEG4.17 cells, may be a result of STAT3-mediated effects on cellular apoptosis and DNA damage.
OBJECTIVE: The inhibition of epidermal growth factor receptor (EGFr) with the monoclonal antibody cetuximab reduces cell proliferation and survival which correlates with increased DNA damage. Since the signal transducer and activator of transcription-3 (STAT-3) is involved in the EGFr-induced signaling pathway, we hypothesized that depletion of STAT-3 may augment cetuximab-induced processes in human head and neck cancer cells. MATERIALS AND METHODS:Human head and neck squamous carcinoma cells (UM-SCC-5) were transfected with short hairpin RNA (shRNA) against STAT-3 (STAT3-2.4 and 2.9 cells). A mutated form of this shRNA was transfected for a control (NEG4.17 cells). Radiosensitivity was assessed by a standard colony formation assay. Proliferation was assessed by daily cell counts following treatment and apoptosis was assessed by an annexin V-FITC assay. The alkaline comet assay was used to assess DNA damage. RESULTS: The STAT-3 knockdown cells (STAT3-2.4 and STAT3-2.9 cells) demonstrated enhanced radiosensitivity compared to control NEG4.17 cells, which correlated with increased apoptosis. Also, the STAT-3 knockdown cells demonstrated decreased proliferation with cetuximab treatments compared to control cells (NEG4.17). The increased cetuximab sensitivity of the STAT-3 knockdown cells correlated with increased apoptosis and DNA damage compared to control cells (NEG4.17). CONCLUSION: These studies revealed that the greater anti-proliferative effects and increased cytotoxicity of cetuximab in the STAT3-2.4 and STAT3-2.9 cells compared to control NEG4.17 cells, may be a result of STAT3-mediated effects on cellular apoptosis and DNA damage.
Authors: M Saki; M Toulany; W Sihver; M Zenker; J-M Heldt; B Mosch; H-J Pietzsch; M Baumann; J Steinbach; H P Rodemann Journal: Strahlenther Onkol Date: 2012-08-10 Impact factor: 3.621
Authors: Nelson Ung; Tracy L Putoczki; Stanley S Stylli; Irvin Ng; John M Mariadason; Timothy A Chan; Hong-Jian Zhu; Rodney B Luwor Journal: Cancer Biol Ther Date: 2014-02-20 Impact factor: 4.742
Authors: Hanneke Stegeman; Johannes H Kaanders; Albert J van der Kogel; Mari Iida; Deric L Wheeler; Paul N Span; Johan Bussink Journal: Radiother Oncol Date: 2013-02-28 Impact factor: 6.280
Authors: Neil D Gross; Julie E Bauman; William E Gooding; William Denq; Sufi M Thomas; Lin Wang; Simion Chiosea; Brian L Hood; Melanie S Flint; Mai Sun; Thomas P Conrads; Robert L Ferris; Jonas T Johnson; Seungwon Kim; Athanassios Argiris; Lori Wirth; Marina N Nikiforova; Jill M Siegfried; Jennifer R Grandis Journal: Clin Cancer Res Date: 2014-04-11 Impact factor: 12.531
Authors: Hanneke Stegeman; Johannes H Kaanders; Deric L Wheeler; Albert J van der Kogel; Marieke M Verheijen; Stijn J Waaijer; Mari Iida; Reidar Grénman; Paul N Span; Johan Bussink Journal: BMC Cancer Date: 2012-10-10 Impact factor: 4.430