1070 Bali Medical Journal 2021; 10(3): 1070-1075 | doi: 10.15562/bmj.v10i3.2896 ORIGINAL ARTICLE ABSTRACT Growth suppression of glioblastoma multiforme cell line response to the combination of Temozolomide and Nimotuzumab Made Agus Mahendra Inggas 1,2 *, Upik Andriani Miskad 2 , Andi Asadul Islam 2 , Eka Julianta Wahjoepramono 1 , Sri Maliawan 3 Background: Researches towards Glioblastoma multiforme therapy (GBM) has been performed, especially in finding the tumor’s genetic cellular expression. The overexpression of EGFR, frequently found in human malignancies, is known to significantly impact cancer cells hallmark traits, such as increased cell survival, proliferation and invasion. This research is performed to figure out the synergistic effect of temozolomide, the main chemotherapy regimen used, and the monoclonal antibody anti-EGFR nimotuzumab in inhibiting the growth of GBM cells in vitro. Methods: We performed cell cultures using GBM U87MG cells and administered nimotuzumab 1000µg/ml and temozolomide 20 µg/ml in different sequences and timings. Inhibition of GBM cell growth is evaluated by measuring Ki-67 and γH2AX levels using flowcytometry and tested with one-way ANOVA. Data were analyzed using SPSS version 21 for Windows. Results: Levels of Ki-67 were in the control group (23.17±1.72), nimotuzumab monotherapy (15.43±1.70), temozolomide monotherapy (14.80±1.37), simultaneous therapy (10.73±1.19), nimotuzumab 24 hours before temozolomide (10.57±1.05), and nimotuzumab 48 hours before temozolomide (14.47±1.37). The level of γH2AX is measured in the control group (11.90±1.25), nimotuzumab monotherapy (29.33±1.91), temozolomide monotherapy (28.13±1.58), simultaneous therapy (41.53±3.51), nimotuzumab 24 hours before temozolomide (39.56±2.06), and nimotuzumab 48 hours before temozolomide (35.93±3.56). Conclusion: This research shows that administration of nimotuzumab simultaneously with temozolomide and nimotuzumab 24 hours before temozolomide effectively inhibits the growth of U87MG GBM cells. Inhibition of EGFR expression before temozolomide administration is able to increase DNA damage and inhibit the proliferation of glioma cells. Keywords: Glioblastoma multiforme, growth suppression, Nimotuzumab, Temozolomide Cite This Article: Inggas, M.A.M., Miskad, U.A., Islam, A.A., Wahjoepramono, E.J., Maliawan, S. 2021. Growth suppression of glioblastoma multiforme cell line response to the combination of Temozolomide and Nimotuzumab. Bali Medical Journal 10(3): 1070-1075. DOI: 10.15562/bmj.v10i3.2896 1 Department Neurosurgery, Faculty of Medicine, Universitas Pelita Harapan, Jakarta, Indonesia 2 Faculty of Medicine, Universitas Hasanuddin, Makassar, Indonesia 3 Department Neurosurgery, Faculty of Medicine, Universitas Udayana, Bali, Indonesia *Corresponding to: Made Agus Mahendra Inggas; Department Neurosurgery, Faculty of Medicine, Universitas Pelita Harapan, Jakarta, Indonesia; made.inggas@lecturer.uph.edu Received: 2021-09-02 Accepted: 2021-12-06 Published:2021-12-30 Bali Medical Journal (Bali MedJ) 2021, Volume 10, Number 3: 1070-1075 P-ISSN.2089-1180, E-ISSN: 2302-2914 Open access: www.balimedicaljournal.org INTRODUCTION Cerebral tumors are the second most common fatal tumor in children under 20 years old and men between 20-39 years old; and the fiſth most common fatal tumor in women 20-39 years old within cancer patients in America. 1 Glioblastoma Multiforme (GBM) is a primary brain tumor with a dismal prognosis for its patients and great lethality. 2 is is caused by the intrinsic characteristic of glioma cells, which is resistance to Temozolomide (TMZ), the main regimen of chemotherapy used. 3,4 Most recent studies indicate that there are other therapeutic pathways to reduce GBM cell growth by inhibiting the expression of epidermal growth factor receptor (EGFR)/EGFRvIII. Increased EGFR expression correlates with tumor drug resistance and increased proliferation of GBM cells. 5,6 e administration of a monoclonal antibody anti-EGFR Nimotuzumab (NMZ) becomes one of the chosen agents with TMZ. 7 Researches performed up to this date has not focused on inhibition, especially using the tumor defensive mechanism. e administration of anti-EGFR concurrently and subsequently with TMZ, with the proper combination, is hoped to slow down cellular growth maximally. By damaging the DNA repair mechanism using EGFR at an early phase, it is expected that the administration of monoclonal antibodies against EGFR before TMZ administration can give a synergistic effect in slowing down GBM growth. Based on those mentioned above, this study aims to figure out the synergistic effect of temozolomide and the monoclonal antibody anti EGFR nimotuzumab in inhibiting the growth of GBM cells in vitro. METHODS is is an in vitro study on the U87MG cell line. In the first step, the U87MG was tested for MGMT methylation using Methyl-specific PCR (MSP) and immunocytochemistry using anti Epidermal Growth Factor Receptor (EGFR) monoclonal antibody at Stem Cell and Cancer Institute (SCI) Jakarta.