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. 2015 Mar 12;6(11):8788–8806. doi: 10.18632/oncotarget.3554

Figure 3. Apoptosis in human GBM neurospheres containing GSCs treated with cetuximab-IONPs.

Figure 3

Transport of EGFR to the cytoskeletal structures. Neurospheres were treated with free IONPs (0.2 mg/ml), cetuximab-IONPs (0.2 mg/ml), control vehicle, or cetuximab alone (50 μg/ml) and expression of apoptotic proteins was evaluated by Western blotting. Elevated levels of cleaved caspase 3 and cleaved PARP were found in neurospheres N08-74 and N08-30 after treatment with cetuximab-IONPs for 3 (A, left) and in neurospheres N08-74 for 14 hs (A, right). Treatment with cetuximab-IONPs was most effective in inducing cleavage of caspase 3 and PARP although some caspase 3 cleavage was also induced by free IONPs in N08-30. In neurospheres N08-1002, induction of caspase 3 and PARP cleavage, and decreased phosphorylation of ERK 44/42 was found after 3 h treatment with cetuximab-IONPs and cetuximab alone, both in the presence and absence of EGF and FGF, caspase 3 was used as a control (B, top). Treatment with cetuximab-IONPs (but not the control conjugated antibody) increased cleavage of PARP in neurospheres N08-1002 whereas no cleavage was observed in NHPC (B, bottom). (C) N08-30 neurospheres were treated as above for 5 hs, lysates were subcellularly fractionated, and analyzed by Western blotting. Elevated levels of wtEGFR were found in the cytoskeletal fraction after cells were treated with cetuximab-IONPs. (D) U87MG and U87MGwtEGFR human GBM cell lines were treated with free IONPs, cetuximab-IONPs, or cetuximab alone. Apoptosis, as indicated by activation of caspase 3 cleavage, was seen only in the U87MGwtEGFR cell line treated with cetuximab-IONPs.