Original Research Paper Sorafenib and lithium chloride combination treatment shows promising synergistic effects in human glioblastoma multiforme cells in vitro but midkine is not implicated Pulat Akın Sabancı 1 , Mine Ergu ¨ven 2 , Nuray Yazıhan 3 , Esin Aktas ¸ 4 , Yavuz Aras 1 , Erdinc ¸ Civelek 5 , Aydın Aydoseli 1 , Murat I ˙ mer 1 , Mehmet Gu ¨rtekin 2 , Ayhan Bilir 6 1 Department of Neurosurgery, Istanbul Faculty of Medicine, Istanbul University, Turkey, 2 Faculty of Health Sciences, Istanbul Aydın University, Turkey, 3 Department of Pathophysiology, Faculty of Medicine, Ankara University, Turkey, 4 Department of Immunology, Experimental Medicine Research Institute, Istanbul University, Turkey, 5 Department of Neurosurgery, Faculty of Medicine, Baskent University, Istanbul, Turkey, 6 Department of Histology and Embryology, Istanbul Faculty of Medicine, Istanbul University, Turkey Objectives: The objectives of this study were to test the effects of the new combination treatment modality, sorafenib (SOR) and lithium chloride (LiCl) and to assess whether midkine (MK) protein has a role in any potential effects. Methods: Monolayer and spheroid cultures of T98G human glioblastoma multiforme (GBM) cells were treated with LiCl and SOR (inhibition concentration 50 value 5 100 mM), or their combination, or were left untreated (control). Cell proliferation and apoptotic indices, the mechanism of action, and the levels of apoptotic and anti-apoptotic proteins were evaluated in monolayer cultures and ultrastructure was evaluated by transmission electron microscopy (TEM) in spheroid cultures after for 72 hours. Results: All drug applications decreased cell numbers and increased the apoptotic index. The combination shows a synergistic effect. In the combination group, the decrease in cell numbers and the increase in the apoptotic index were significantly greater than with the individual drugs (P , 0.01). The combination treatment led to the greatest decreases in MRP-1 and p170 levels; but the greatest decreases in p-STAT-3, p-ERK (P , 0.05), p-AKT, p-GSK-3-beta (P , 0.01), EGFR (P , 0.01), NF-kappa-b levels were with SOR alone, followed by the combination. The decreases in MK levels in the SOR and combination groups were similar (P 5 0.06). Severe ultrastructural damage was more frequently observed in the combination group compared with the other groups. Conclusions: These results suggest the possibility that the addition of LiCl to SOR could improve the prognosis in at least some patients who need both cancer and psychotherapy and indicate the need for further studies. Keywords: Combination chemotherapy, Glioblastoma, Lithium chloride, Midkine, Sorafenib Introduction Glioblastoma multiforme (GBM) is the most common and lethal type of primary brain tumor, graded as IV on a World Health Organization (WHO) classification system scale. 1 Glioblastoma multiformes arise from glial cells, which are the building-block cells of the connective and supportive tissues in the central nervous system. Important characteristics of GBMs are aberrant cellular proliferation, diffuse infiltration, propensity for necrosis, robust angiogenesis, high resistance to apoptosis, and genomic instability. 2,3 The intratumoral heterogeneity combined with the putative cancer stem cell (CSC) subpopulation and incomplete atlas of epigenetic lesions are the reasons for the poor prognosis and malignancy. 4,5 The aver- age survival time remains short because of the limited treatment options related to the tumor’s capacity for resistance and fast recurrence. Despite the extensive surgical resection, under the control of current pre- operative and post-operative high-tech radiological imaging techniques, which is followed by new- generation radiotherapy, supportive chemotherapy, Correspondence to: Mine Ergu ¨ ven, Faculty of Engineering, Istanbul Aydın University, Bes ¸yol Mah, Ino ¨nu ¨ Street, No: 38, Apartment K, Sefako ¨y Ku ¨c ¸u ¨kc ¸ekmece, Istanbul, Turkey. Email: mine.erguven@gmail. com ß W. S. Maney & Son Ltd 2014 DOI 10.1179/1743132813Y.0000000283 Neurological Research 2014 VOL. 36 NO.3 189