Proteomic Analysis of Human Glioblastoma Cell Lines with Different Response to Nitric Oxide

The glioblastoma multiforme is the most aggressive astrocytoma tumor, affecting brain glial cells. Affected patients, even after aggressive treatments (e.g. surgical resection, radiotherapy and chemotherapy) have a median survival of less than one year. Nitric oxide (NO) has emerged as a potential anti-oncogenic agent able to overcome tumor resistance, unfortunately it isn’t in all tumor cases. The development of cellular models resistant to various cytotoxic stimuli is crucial for the comprehension of molecular mechanisms at the basis of this phenomena. CCF-STTG1 and T98G cell lines, both derived from glioblastoma multiforme were adopted to monitor the effect of NO donors. CCF-STTG1 cells respond to treatment with different NO donors inhibiting proliferation with a ceramide-dependent mechanism, whereas T98G are totally resistant. Molecular differences between these two cell lines were assessed applying 2D-DIGE and mass spectrometry. Results indicated an increased abundance of chaperone and stress response proteins in T98G cell line. These changes can create an adverse environment for NO action, justifying T98G enhanced resistance. Furthemore, some proteins, involved in the pathway that regulates ceramide trafficking between ER and Golgi, resulted deregulated in T98G compared to CCF-STTG1, this probably counteracts ceramide accumulation in ER avoiding proliferation arrest. In conclusion, proteomic analysis highlighted a more effective control of the intracellular redox status and a more efficient ceramide removal from ER in T98G cell line, that can account for the intrinsic resistance to NO action. This protein set could provide new insight in the prediction of NO response in tumor treatment.