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A novel biguanide (IM1761065) inhibits bioenergetics of glioblastoma tumorspheres



Glioblastoma (GBM) is a rapidly growing tumor in the central nervous system with altered metabolism. Depleting the bioenergetics of tumors with biguanides have been suggested as an effective therapeutic approach for treating GBMs. The purpose of this study was to determine the effects of IM1761065, a novel biguanide with improved pharmacokinetics, on GBM-tumorspheres (TSs).


The biological activities of IM1761065 on GBM-TSs, including their effects on viability, ATP levels, cell cycle, stemness, invasive properties, and transcriptomes were examined. The in vivo efficacy of IM1761065 was tested in a mouse orthotopic xenograft model.


IM1761065 decreased the viability and ATP levels of GBM-TSs in a dose-dependent manner, and reduced basal and spare respiratory capacity in patient-derived GBM-TS, as measured by the oxygen consumption rate. Sphere formation, expression of stemness-related proteins, and invasive capacity of GBM-TSs were also significantly suppressed by IM1761065. A gene-ontology comparison of IM1761065-treated groups showed that the expression levels of stemness-related, epithelial mesenchymal transition-related, and mitochondrial complex I genes were also significantly downregulated by IM1761065. An orthotopic xenograft mouse model showed decreased bioluminescence in IM1761065-treated cell-injected mice at 5 weeks. IM1761065-treated group showed longer survival than the control group (P = 0.0289, log-rank test).


IM1761065 is a potent inhibitor of oxidative phosphorylation. The inhibitory effect of IM1761065 on the bioenergetics of GBM-TS suggests that this novel compound could be used as a new drug for the treatment of GBM.

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Epithelial-mesenchymal transition




Propidium iodide


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We thank Prof. Lang (Department of Neurosurgery, M. D. Anderson Cancer Center, The University of Texas, Houston, Texas, USA) for providing patient derived GBM tumorspheres (GSC11). IM1761065 was provided by ImmunoMet Therapeutics (Houston, Texas, USA).


This work was supported by a National Research Foundation of Korea (NRF) Grant funded by the Korean government (MSIT) (NRF-2019R1A2C3004155) and the Bio & Medical Technology Development Program of the NRF funded by the Ministry of Science & ICT (NRF-2020M3E5E2037960, NRF-2020M2D9A2092372, NRF-2020M3A9E8024890). This study was supported by the “Team Science Award” of Yonsei University College of Medicine (6-2021-0006).

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Authors and Affiliations



THR, JHL, JKS, and SGK conceptualized and initiated the project. JHL, SJK, and JKS performed the experiments and analyzed the data. SJY, JP, and WYT analyzed microarray and gene ontology databases. THR, JHL, SJK, JKS, SJY, and SGK drafted the manuscript. WYT, SHK, and JHC revised the manuscript critically. All authors have read and approved the manuscript.

Corresponding author

Correspondence to Seok-Gu Kang.

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Conflict of interest

Seok-Gu Kang is a scientific advisor for ImmunoMet Therapeutics. The other authors declare no conflict of interest.

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All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. All procedures performed in studies involving animals followed the ethical standards of the institution or practice at which the studies were conducted.

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Supplementary Information

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Supplementary file1 (DOCX 21 kb)


Supplementary file2 Suppl. Fig. 1 Average body weight of 5 mice after daily intraperitoneal administration of IM1761065 (10 mg/kg) for 4 weeks. Body weight did not decrease by more than 15% during this period (PDF 20 kb)


Supplementary file3 Suppl. Fig. 2 Combination effect of IM1761065 and temozolomide a. Combined therapy of IM1761065 with (5 µM) temozolomide (250 µM) also significantly decreased the viability of all GBM-TSs. b. ATP levels were significantly decreased after combined treatment with IM1761065 and temozolomide (PDF 633 kb)


Supplementary file4 Suppl. Fig. 3 Comparison between the effects of IM1761065 and metformin treatment on viability and ATP levels. After 72 h of treatment with 5 µM IM1761065 or 5 µM metformin, MTS and ATP assays were performed in each GBM-TS. a. Viability and b. ATP levels were significantly decreased in IM1761065-treated groups in all GBM-TSs (PDF 618 kb)


Supplementary file5 Suppl. Fig. 4 Comparison between the effects of IM1761065 and metformin treatments on stemness properties After 72 h of treatment with 5 µM IM1761065, neurosphere formation assay showed a significant decrease in neurosphere formation in all the GBM-TSs than in the control and 5 µM metformin-treated GBM-TSs (PDF 544 kb)


Supplementary file6 Suppl. Fig. 5 Comparison between the effects of IM1761065 and metformin treatment on invasive properties. After 72 h of treatment with 5 µM IM1761065, a three-dimensional invasion assay showed a significant decrease in invasion in U87 and U251 tumorspheres than in the control and 5 µM metformin treated tumorspheres (PDF 705 kb)


Supplementary file7 Suppl. Fig. 6. Comparison between the effects of IM1761065 and other biguanide treatment on biological effect. (a) Cell viability, (b) ATP levels, (c) stemenss, and (d) invasiveness of GBM TS were evaluated after treatment with IM1761065, metformin, phenformin, and HL156A [8]. all biguanides were treated with the same concentration of 5 µM. Differences among groups were compared by one-way ANOVA with Tukey’s post hoc test; means ± SD; *P < 0.05 (PDF 61 kb)

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Roh, T.H., Lee, JH., Kim, S.J. et al. A novel biguanide (IM1761065) inhibits bioenergetics of glioblastoma tumorspheres. J Neurooncol 156, 139–151 (2022).

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  • Biguanide
  • Glioblastoma
  • Tumorsphere
  • IM1761065
  • Bioenergetics