Repurposing Eszopiclone A Non-Benzodiazepine GABA-A Modulator Synergizing with PD-1/PD-L1 Immunotherapy to Reprogram the Glioma Microenvironment – A Perspective

Background. Gliomas especially glioblastoma multiforme (GBM) are among the most aggressive primary brain tumors, characterized by rapid proliferation, metabolic plasticity, and a profoundly immunosuppressive tumor microenvironment (TME). Dysregulation of chloride homeostasis, glutamatergic excitotoxicity, and aberrant GABAergic signaling have recently emerged as mechanistic contributors to glioma progression and immune evasion.

Purpose of the Study: to propose eszopiclone, a non-benzodiazepine GABA-A receptor modulator, as a repurposed adjunct capable of reprogramming glioma metabolism and enhancing responsiveness to PD-1/PD-L1 immunotherapy. Material and Methods. A narrative perspective review was conducted based on literature retrieved from PubMed, Scopus, Web of Science, and Science Direct. A total of 312 sources were screened; 154 articles published between 2005 and 2024 were selected for detailed analysis based on relevance to GABAergic signaling, glioma metabolism, macrophage polarization, chloride channel regulation, and immune checkpoint interactions.

Results. Eszopiclone-mediated GABA-A activation restores chloride influx and suppresses depolarization-driven Ca²+/NFAT and PI3K/AKT/mTOR signaling, resulting in G1/S arrest and enhanced apoptotic susceptibility. Within the TME, GABA-A signaling reduces NF-κB and STAT3 phosphorylation and shifts microglia/glioma-associated macrophages from protumoral M2 (CD206+/IL-10+) to antitumoral M1 (iNOS+/IFN-γ+) polarization, facilitating improved antigen presentation and T-cell infiltration. Evidence from GABAergic models in melanoma and breast cancer suggests that modulation of this axis may downregulate PD-L1 expression and potentiate responsiveness to PD-1/PD-L1 inhibitors, supporting a mechanistic rationale for synergy in glioma.

Conclusion. Repurposing eszopiclone introduces a novel neuroimmuno-oncologic therapeutic concept bridging neuropharmacology and checkpoint immunotherapy. Owing to its blood-brain-barrier penetration, clinical safety, and receptor selectivity, eszopiclone represents a feasible candidate for combination strategies with PD-1/PD-L1 blockade. Further preclinical models, retrospective analyses, and early-phase trials are warranted to validate its immunomodulatory potential and define its translational relevance in glioma therapy.

1. Wu W., Klockow J.L., Zhang M., Lafortune F., Chang E., Jin L., Wu Y., Daldrup-Link H.E. Glioblastoma multiforme (GBM): an overview of current therapies and mechanisms of resistance. Pharmacol Res. 2021; 171: 105780. doi: 10.1016/j.phrs.2021.105780.

2. Duan M., Cao R., Yang Y., Chen X., Liu L., Ren B., Wang L., Goh B.C. Blood-brain barrier conquest in glioblastoma nanomedicine: strategies, clinical advances, and emerging challenges. Cancers. 2024; 16(19): 3300. doi: 10.3390/cancers16193300.

3. Nateghi S., Rezayof A., Kouhkan F., Delphi L., Davisaraei Y.B., Rostami F., Tirgar F., Sepehri H. Growth of the prefrontal cortical glioblastoma altered cognitive and emotional behaviors via mediating miRNAs and GABA-A receptor signaling pathways in rats. Brain Res Bull. 2025; 221: 111227. doi: 10.1016/j.brainresbull.2025.111227.

4. Huang D., Alexander P.B., Li Q.J., Wang X.F. GABAergic signaling beyond synapses: an emerging target for cancer therapy. Trends Cell Biol. 2023; 33(5): 403–12. doi: 10.1016/j.tcb.2022.08.004.

5. Contreras-Zárate M.J., Alvarez-Eraso K.L.F., Jaramillo-Gómez J.A., Littrell Z., Tsuji N., Ormond D.R., Karam S.D., Kabos P., Cittelly D.M. Short-term topiramate treatment prevents radiation-induced cytotoxic edema in preclinical models of breast-cancer brain metastasis. Neuro Oncol. 2023; 25(10): 1802–14. doi: 10.1093/neuonc/noad070.

6. Li T.J., Jiang J., Tang Y.L., Liang X.H. Insights into the leveraging of GABAergic signaling in cancer therapy. Cancer Med. 2023; 12(13): 14498–510. doi: 10.1002/cam4.6102.

7. Rosner S., Englbrecht C., Wehrle R., Hajak G., Soyka M. Eszopiclone for insomnia. Cochrane Database Syst Rev. 2018; 10(10): CD010703. doi: 10.1002/14651858.CD010703.pub2.

8. Ghit A., Assal D., Al-Shami A.S., Hussein D.E.E. GABAA receptors: structure, function, pharmacology, and related disorders. J Genet Eng Biotechnol. 2021; 19: 123. doi: 10.1186/s43141-021-00224-0.

9. Smits A., Jin Z., Elsir T., Pedder H., Nistér M., Alafuzoff I., Dimberg A., Edqvist P.H., Pontén F., Aronica E., Birnir B. GABA-A channel subunit expression in human glioma correlates with tumor histology and clinical outcome. PLoS One. 2012; 7(5): 37041. doi: 10.1371/journal.pone.0037041.

10. Barron T., Yalçın B., Su M., Byun Y.G., Gavish A., Shamardani K., Xu H., Ni L., Soni N., Mehta V., Maleki Jahan S., Kim Y.S., Taylor K.R., Keough M.B., Quezada M.A., Geraghty A.C., Mancusi R., Vo L.T., Castañeda E.H., Woo P.J., Petritsch C.K., Vogel H., Kaila K., Monje M. GABAergic neuron-to-glioma synapses in diffuse midline gliomas. Nature. 2025; 639(8056): 1060–68. doi: 10.1038/s41586-024-08579-3.

11. Bhattacharya D., Gawali V.S., Kallay L., Toukam D.K., Koehler A., Stambrook P., Krummel D.P., Sengupta S. Therapeutically leveraging GABAA receptors in cancer. Exp Biol Med. 2021; 246(19): 2128–35. doi: 10.1177/15353702211032549.

12. Lanza M., Casili G., Campolo M., Paterniti I., Colarossi C., Mare M., Giuffrida R., Caffo M., Esposito E., Cuzzocrea S. Immunomodulatory effect of microglia-released cytokines in gliomas. Brain Sci. 2021; 11(4): 466. doi: 10.3390/brainsci11040466.

13. McDonough K.E., Hammond R., Wang J., Tierney J., Hankerd K., Chung J.M., La J.H. Spinal GABAergic disinhibition allows microglial activation mediating the development of nociplastic pain in male mice. Brain Behav Immun. 2023; 107: 215–24. doi: 10.1016/j.bbi.2022.10.013.

14. Kim K.K., Sheppard D., Chapman H.A. TGF-β1 signaling and tissue fibrosis. Cold Spring Harb Perspect Biol. 2018; 10(4): a022293. doi: 10.1101/cshperspect.a022293.

15. Badalotti R., Dalmolin M., Malafaia O., Ribas Filho J.M., Roesler R., Fernandes M.A.C., Isolan G.R. Gene expression of GABAA receptor subunits and association with patient survival in glioma. Brain Sci. 2024; 14(3): 275. doi: 10.3390/brainsci14030275.

16. Absalom N.L., Liao V.W.Y., Johannesen K.M.H., Gardella E., Jacobs J., Lesca G., Gokce-Samar Z., Arzimanoglou A., Zeidler S., Striano P., Meyer P., Benkel-Herrenbrueck I., Mero I.L., Rummel J., Chebib M., Møller R.S., Ahring P.K. Gain-of-function and loss-of-function GABRB3 variants lead to distinct clinical phenotypes in patients with developmental and epileptic encephalopathies. Nat Commun. 2022; 13: 1822. doi: 10.1038/s41467-022-29280-x.

17. Naffaa M.M., Hibbs D.E., Chebib M., Hanrahan J.R. Pharmacological effect of GABA analogues on GABA-ϱ2 receptors and their subtype selectivity. Life. 2022; 12(1): 127. doi: 10.3390/life12010127.

18. Yang Y., Ren L., Li W., Zhang Y., Zhang S., Ge B., Yang H., Du G., Tang B., Wang H., Wang J. GABAergic signaling as a potential therapeutic target in cancers. Biomed Pharmacother. 2023; 161: 114410. doi: 10.1016/j.biopha.2023.114410.

19. Zhang X., Zhang R., Zheng Y., Shen J., Xiao D., Li J., Shi X., Huang L., Tang H., Liu J., He J., Zhang H. Expression of gammaaminobutyric acid receptors on neoplastic growth and prediction of prognosis in non-small cell lung cancer. J Transl Med. 2013; 11: 102. doi: 10.1186/1479-5876-11-102.

20. Xie M., Qin H., Liu L., Wu J., Zhao Z., Zhao Y., Fang Y., Yu X., Su C. GABA regulates metabolic reprogramming to mediate the development of brain metastasis in non-small cell lung cancer. J Exp Clin Cancer Res. 2025; 44(1): 61. doi: 10.1186/s13046-025-03315-9.

21. Monti J.M., Pandi-Perumal S.R. Eszopiclone: its use in the treatment of insomnia. Neuropsychiatr Dis Treat. 2007; 3(4): 441–53.

22. Hanson S.M., Morlock E.V., Satyshur K.A., Czajkowski C. Structural requirements for eszopiclone and zolpidem binding to the gammaaminobutyric acid type-A (GABAA) receptor are different. J Med Chem. 2008; 51(22): 7243–52. doi: 10.1021/jm800889m.

23. Zhu S., Sridhar A., Teng J., Howard R.J., Lindahl E., Hibbs R.E. Structural and dynamic mechanisms of GABAA receptor modulators with opposing activities. Nat Commun. 2022; 13: 4582. doi: 10.1038/s41467-022-32212-4.

24. Barron T., Yalçın B., Su M., Byun Y.G., Gavish A., Shamardani K., Xu H., Ni L., Soni N., Mehta V., Maleki Jahan S., Kim Y.S., Taylor K.R., Keough M.B., Quezada M.A., Geraghty A.C., Mancusi R., Vo L.T., Castañeda E.H., Woo P.J., Petritsch C.K., Vogel H., Kaila K., Monje M. GABAergic neuron-to-glioma synapses in diffuse midline gliomas. Nature. 2025; 639(8056): 1060–68. doi: 10.1038/s41586-024-08579-3.

25. Nawafleh S., Qaswal A.B., Suleiman A., Alali O., Zayed F.M., AlAdwan M.A.O., Bani Ali M. GABA receptors can depolarize the neuronal membrane potential via quantum tunneling of chloride ions: a quantum mathematical study. Cells. 2022; 11(7): 1145. doi: 10.3390/cells11071145.

26. Virtanen M.A., Uvarov P., Hübner C.A., Kaila K. NKCC1, an elusive molecular target in brain development: making sense of the existing data. Cells. 2020; 9(12): 2607. doi: 10.3390/cells9122607.

27. McMoneagle E., Zhou J., Zhang S., Liu Y., Wu G., Wang Y., Tang J., Zhang J., Zhang X., Wang X., Zhang X., Zhang H., Zhang J., Xu Z., Tang Y. Neuronal K+-Clcotransporter KCC2 as a promising drug target for epilepsy treatment. Acta Pharmacol Sin. 2024; 45(1): 1–22. doi: 10.1038/s41401-023-01149-9.

28. Altieri R., Barbagallo D., Certo F., Broggi G., Ragusa M., Di Pietro C., Caltabiano R., Magro G., Peschillo S., Purrello M., Barbagallo G. Peritumoral microenvironment in high-grade gliomas: from FLAIRectomy to microglia-glioma cross-talk. Brain Sci. 2021; 11(2): 200. doi: 10.3390/brainsci11020200.

29. Badalotti R., Dalmolin M., Malafaia O., Ribas Filho J.M., Roesler R., Fernandes M.A.C., Isolan G.R. Gene expression of GABAA receptor subunits and association with patient survival in glioma. Brain Sci. 2024; 14(3): 275. doi: 10.3390/brainsci14030275.

30. Connaughton V.P., Nelson R., Bender A.M. Electrophysiological evidence of GABAA and GABAC receptors on zebrafish retinal bipolar cells. Vis Neurosci. 2008; 25(2): 139–53. doi: 10.1017/s0952523808080322.

31. Anilkumar S., Wright-Jin E. NF-κB as an inducible regulator of inflammation in the central nervous system. Cells. 2024; 13(6): 485. doi: 10.3390/cells13060485.

32. Tian J., Kaufman D.L. The GABA and GABA-receptor system in inflammation, anti-tumor immune responses, and COVID-19. Biomedicines. 2023; 11(2): 254. doi: 10.3390/biomedicines11020254.

33. Wang J., Li S., Lan Y., Chen Y., Gao Y., Zhang X., Li X., Liu X., Wang J. Glioma-associated macrophages: unraveling their dual role in the microenvironment and therapeutic implications. Curr Med. 2024; 3: 4. doi: 10.1007/s44194-024-00031-y.

34. Lin H., Liu C., Hu A., Zhang D., Yang H., Mao Y. Understanding the immunosuppressive microenvironment of glioma: mechanistic insights and clinical perspectives. J Hematol Oncol. 2024; 17(1): 31. doi: 10.1186/s13045-024-01544-7.

35. Hong S., You J.Y., Paek K., Park J., Kang S.J., Han E.H., Choi N., Chung S., Rhee W.J., Kim J.A. Inhibition of tumor progression and M2 microglial polarization by extracellular vesicle-mediated microRNA-124 in a 3D microfluidic glioblastoma microenvironment. Theranostics. 2021; 11(19): 9687–704. doi: 10.7150/thno.60851.

36. Zhang B., Vogelzang A., Miyajima M., Sugiura Y., Wu Y., Chamoto K., Nakano R., Hatae R., Menzies R.J., Sonomura K., Hojo N., Ogawa T., Kobayashi W., Tsutsui Y., Yamamoto S., Maruya M., Narushima S., Suzuki K., Sugiya H., Murakami K., Hashimoto M., Ueno H., Kobayashi T., Ito K., Hirano T., Shiroguchi K., Matsuda F., Suematsu M., Honjo T., Fagarasan S. B cell-derived GABA elicits IL-10+ macrophages to limit anti-tumour immunity. Nature. 2021; 599(7885): 471–76. doi: 10.1038/s41586-021-04082-1.

37. Fujimura T., Kambayashi Y., Aiba S. Crosstalk between regulatory T cells (Tregs) and myeloid derived suppressor cells (MDSCs) during melanoma growth. Oncoimmunology. 2012; 1(8): 1433–34. doi: 10.4161/ onci.21176.

38. McCrae C.S., Ross A., Stripling A., Dautovich N.D. Eszopiclone for late-life insomnia. Clin Interv Aging. 2007; 2(3): 313–26. doi: 10.2147/cia.s1441.

39. Xiao L., Li X., Fang C., Yu J., Chen T. Neurotransmitters: promising immune modulators in the tumor microenvironment. Front Immunol. 2023; 14: 1118637. doi: 10.3389/fimmu.2023.1118637.

40. Ortiz R., Perazzoli G., Cabeza L., Jiménez-Luna C., Luque R., Prados J., Melguizo C. Temozolomide: an updated overview of resistance mechanisms, nanotechnology advances and clinical applications. Curr Neuropharmacol. 2021; 19(4): 513–37. doi: 10.2174/1570159X18 666200626204005.

41. Ren J., Xu B., Ren J., Liu Z., Cai L., Zhang X., Wang W., Li S., Jin L., Ding L. The Importance of M1-and M2-Polarized Macrophages in Glioma and as Potential Treatment Targets. Brain Sci. 2023; 13(9): 1269. doi: 10.3390/brainsci13091269.

42. Ning J., Wang Y., Tao Z. The complex role of immune cells in antigen presentation and regulation of T-cell responses in hepatocellular carcinoma: progress, challenges, and future directions. Frontiers in immunology. 2024; 15: 1483834. doi: 10.3389/fimmu.2024.1483834.

43. Squarize C.H., Castilho R.M., Sriuranpong V., Pinto D.S.Jr, Gutkind J.S. Molecular cross-talk between the NFkappaB and STAT3 signaling pathways in head and neck squamous cell carcinoma. Neoplasia. 2006; 8(9): 733–46. doi: 10.1593/neo.06274.

44. Cheng C.C., Chang J., Ho A.S., Sie Z.L., Peng C.L., Wang C.L., Dev K., Chang C.C. Tumor-intrinsic IFNα and CXCL10 are critical for immunotherapeutic efficacy by recruiting and activating T lymphocytes in tumor microenvironment. Cancer Immunol Immunother. 2024; 73(9): 175. doi: 10.1007/s00262-024-03761-y.

45. Mathan S.V., Singh R.P. Cancer Stem Cells Connecting to Immunotherapy: Key Insights, Challenges, and Potential Treatment Opportunities. Cancers (Basel). 2025; 17(13): 2100. doi: 10.3390/cancers17132100.

46. Zhao Y., Xu J., Yang K., Bao L. Targeting GABA signaling in the tumor microenvironment: implications for immune cell regulation and immunotherapy resistance. Front Immunol. 2025; 16: 1645718. doi: 10.3389/fimmu.2025.1645718.

47. Hou B., Chen T., Zhang H., Li J., Wang P., Shang G. The E3 ubiquitin ligases regulate PD-1/PD-L1 protein levels in tumor microenvironment to improve immunotherapy. Front Immunol. 2023; 14: 1123244. doi: 10.3389/fimmu.2023.1123244.

48. Hu X., Wang J., Chu M., Liu Y., Wang Z.W., Zhu X. Emerging Role of Ubiquitination in the Regulation of PD-1/PD-L1 in Cancer Immunotherapy. Mol Ther. 2021; 29(3): 908–19. doi: 10.1016/j.ymthe.2020.12.03.

49. Gao P., Li X., Duan Z., Wang Y., Li Y., Wang J., Luo K., Chen J. Improvement of the Anticancer Efficacy of PD-1/PD-L1 Blockade: Advances in Molecular Mechanisms and Therapeutic Strategies. MedComm. 2025; 6(8): 70274. doi: 10.1002/mco2.70274.