BBoric Acid Inhibits Inflammasome Activation in LPS-Stimulated Glioblastoma Cells

Abstract

Aim: Gliomas, the most common primary brain tumors, exhibit diverse clinical features and a poor prognosis. Inflammasome activation is closely linked to the inflammatory microenvironment in the central nervous system, regulated by inflammasomes like nucleotide-binding domain leucine-rich family pyrin-containing 3 (NLRP3), implicated in glioma development. However, NLRP3's role in human glioma remains unclear. This study explores the effects of boric acid on U87 glioblastoma cells and NLRP3 inflammasome activation. Material and Methods: Employing the enzyme-linked immunosorbent assay (ELISA) method, we assessed cell viability, 5-bromo-2'-deoxyuridine (BrdU), NLRP3, interleukin (IL)-1β, IL-18, caspase 1, apoptosis inducing factor (AIF), and cytochrome c levels in U87 cells exposed to various concentrations of boric acid for 24, 48, and 72 hours. Results: Our findings revealed a time- and concentration-dependent reduction in U87 cell viability following exposure to boric acid concentrations within the 0-6.4 mM range. BrdU analysis indicated decreased cell proliferation after 24 hours of boric acid application. Stimulation of inflammasome activation in U87 cells using lipopolysaccharide (LPS) resulted in elevated levels of NLRP3, IL-1β, IL-18, and caspase-1. However, boric acid application countered this effect, reducing inflammasome activation. Additionally, treatment with boric acid+LPS induced AIF and cytochrome c levels, leading to apoptosis. Conclusion: Our results demonstrated that boric acid inhibited NLRP3 inflammasome activation in U87 cells, consequently suppressing cell viability. This suggests that by impeding the NLRP3 inflammasome, boric acid mitigates the inflammotary microenvironment, offering potential therapeutic advantages in the progression of glioblastoma.

Keywords

• Inflammasome activation
• Glioblastoma
• Boric acid

Borik Asit LPS ile Uyarılan Glioblastoma Hücrelerinde İnflamazom Aktivasyonunu İnhibe Eder

Abstract

Amaç: En sık görülen primer beyin tümörleri olan gliomalar, çeşitli klinik özellikler ve kötü prognoz sergiler. İnflamazom aktivasyonu, glioma gelişiminde rol oynayan, nükleotid bağlama alanı lösin açısından zengin aile pirin içeren 3 (NLRP3) gibi inflamazomlar tarafından düzenlenen, merkezi sinir sistemindeki inflamatuar mikro ortamla yakından bağlantılıdır. Ancak NLRP3'ün insan gliomasındaki rolü belirsizliğini koruyor. Bu çalışma borik asidin U87 glioblastoma hücreleri ve NLRP3 inflamazom aktivasyonu üzerindeki etkilerini araştırmaktadır. Gereç ve Yöntemler: Enzime bağlı immünosorbent analizi (ELISA) yöntemini kullanarak 24, 48 ve 72 saat boyunca çeşitli borik asit konsantrasyonlarına maruz kalan U87 hücrelerindeki hücre canlılığını, 5-bromo-2'-deoksiüridin (BrdU), NLRP3, interlökin (IL)-1β, IL-18, kaspaz 1, apoptoz indükleyici faktörü (AIF) ve sitokrom c seviyelerini değerlendirdik. Bulgular: Sonuçlarımız, 0-6,4 mM aralığında borik asit konsantrasyonlarına maruz kalmanın ardından U87 hücre canlılığında zamana ve konsantrasyona bağlı bir azalma olduğunu ortaya koydu. BrdU analizi, 24 saatlik borik asit uygulamasından sonra hücre çoğalmasının azaldığını gösterdi. Lipopolisakkarit (LPS) kullanılarak U87 hücrelerinde inflamatuar aktivasyonun uyarılması, yüksek NLRP3, IL-1β, IL-18 ve kaspaz-1 seviyeleriyle sonuçlandı. Ancak borik asit uygulaması bu etkiyi ortadan kaldırarak inflamazom aktivasyonu azalttı. Ayrıca borik asit+LPS tedavisi AIF ve sitokrom c düzeylerini indükleyerek apoptoza yol açtı. Sonuç: Bulgularımız borik asidin U87 hücrelerinde NLRP3 inflamatuar aktivasyonunu inhibe ettiğini, dolayısıyla hücre canlılığını baskıladığını gösterdi. Bu, borik asidin NLRP3 inflamatuarını engelleyerek inflamatuar mikro ortamı hafiflettiğini ve glioblastomanın ilerlemesinde potansiyel terapötik avantajlar sunduğunu göstermektedir.

Keywords

• İnflamazom aktivasyonu
• Glioblastoma
• Borik asit

References

1. Stupp R, Taillibert S, Kanner AA, Kesari S, Steinberg DM, Toms SA, et al. Maintenance therapy with tumor-treating fields plus temozolomide vs temozolomide alone for glioblastoma: a randomized clinical trial. JAMA. 2015; 314(23): 2535-43.
2. Tosoni A, Franceschi E, Poggi R, Brandes AA. Relapsed glioblastoma: treatment strategies for ınitial and subsequent recurrences. Curr Treat Options Oncol. 2016; 17(9): 49.
3. Rathinam VA, Fitzgerald KA. Inflammasome complexes: emerging mechanisms and effector functions. Cell. 2016; 165(4): 792-800.
4. Akira S, Uematsu S, Takeuchi O. Pathogen recognition and innate immunity. Cell. 2006; 124(4): 783-801.
5. Koizumi Y, Toma C, Higa N, Nohara T, Nakasone N, Suzuki T. Inflammasome activation via intracellular NLRs triggered by bacterial infection. Cell Microbiol. 2012; 14(2): 149-54.
6. Tarassishin L, Casper D, Lee SC. Aberrant expression of interleukin-1β and inflammasome activation in human malignant gliomas. PLoS One. 2014; 9(7): e103432.
7. Lamkanfi M, Dixit VM. Mechanisms and functions of inflammasomes. Cell. 2014; 157(5): 1013-22.
8. Wang H, Wang Y, Du Q, Lu P, Fan H, Lu J, et al. Inflammasome-independent NLRP3 is required for epithelial-mesenchymal transition in colon cancer cells. Exp Cell Res. 2016; 342(2): 184-92.

9. Argust P. Distribution of boron in the environment. Biol Trace Element Res. 1998; 66: 131-43.
10. Scorei RI, Popa R Jr. Boron-containing compounds as preventive and chemotherapeutic agents for cancer. Anticancer Agents Med Chem. 2010; 10(4): 346-51.
11. Ayhanci A, Tanriverdi DT, Sahinturk V, Cengiz M, Appak-Baskoy S, Sahin IK. Protective effects of boron on cyclophosphamide-ınduced bladder damage and oxidative stress in rats. Biol Trace Elem Res. 2020; 197(1): 184-91.
12. Kulkarni S, Bhandary D, Singh Y, Monga V, Thareja S. Boron in cancer therapeutics: An overview. Pharmacol Ther. 2023; 251: 108548.
13. Hacioglu C, Kar F, Kacar S, Sahinturk V, Kanbak G. High concentrations of boric acid trigger concentration-dependent oxidative stress, apoptotic pathways and morphological alterations in du-145 human prostate cancer cell line. Biol Trace Elem Res. 2020; 193(2): 400-9.
14. Hacioglu C, Kar F, Davran F, Tuncer C. Borax regulates iron chaperone- and autophagy-mediated ferroptosis pathway in glioblastoma cells. Environ Toxicol. 2023; 38(7): 1690-701.
15. Roosen K, Scheld M, Mandzhalova M, Clarner T, Beyer C, Zendedel A. CXCL12 inhibits inflammasome activation in LPS-stimulated BV2 cells. Brain Res. 2021; 1763: 147446.
16. Zhu H, Cao X. NLR members in inflammation-associated carcinogenesis. Cell Mol Immunol. 2017; 14(5): 403-5.
17. Huang J, Liu F, Liu Z, Tang H, Wu H, Gong Q, et al. Immune checkpoint in glioblastoma: promising and challenging. Front Pharmacol. 2017; 8: 242.
18. Deretic V. Autophagy in inflammation, infection, and immunometabolism. Immunity. 2021; 54(3): 437-53.
19. Lin TY, Tsai MC, Tu W, Yeh HC, Wang SC, Huang SP, et al. Role of the NLRP3 ınflammasome: ınsights ınto cancer hallmarks. Front Immunol. 2021; 11: 610492.
20. Vafaei S, Taheri H, Hajimomeni Y, Fakhre Yaseri A, Abolhasani Zadeh F. The role of NLRP3 inflammasome in colorectal cancer: potential therapeutic target. Clin Transl Oncol. 2022; 24(10): 1881-9.
21. Munoz L, Yeung YT, Grewal T. Oncogenic Ras modulates p38 MAPK-mediated inflammatory cytokine production in glioblastoma cells. Cancer Biol Ther. 2016; 17(4): 355-63.
22. Tarassishin L, Casper D, Lee SC. Aberrant expression of interleukin-1β and inflammasome activation in human malignant gliomas. PLoS One. 2014; 9(7): e103432.
23. Fathima Hurmath K, Ramaswamy P, Nandakumar DN. IL-1β microenvironment promotes proliferation, migration, and invasion of human glioma cells. Cell Biol Int. 2014; 38(12): 1415-22.
24. Shang S, Wang L, Zhang Y, Lu H, Lu X. The beta-hydroxybutyrate suppresses the migration of glioma cells by ınhibition of NLRP3 inflammasome. Cell Mol Neurobiol. 2018; 38(8): 1479-89.
25. Allen IC, TeKippe EM, Woodford RM, Uronis JM, Holl EK, Rogers AB, et al. The NLRP3 inflammasome functions as a negative regulator of tumorigenesis during colitis-associated cancer. J Exp Med. 2010; 207(5): 1045-56.
26. Wei Q, Mu K, Li T, Zhang Y, Yang Z, Jia X, et al. Deregulation of the NLRP3 inflammasome in hepatic parenchymal cells during liver cancer progression. Lab Invest. 2014; 94(1): 52-62.
27. Wang H, Wang Y, Du Q, Lu P, Fan H, Lu J, et al Inflammasome-independent NLRP3 is required for epithelial-mesenchymal transition in colon cancer cells. Exp Cell Res. 2016; 342(2): 184-92.
28. Wang Y, Kong H, Zeng X, Liu W, Wang Z, Yan X, et al. Activation of NLRP3 inflammasome enhances the proliferation and migration of A549 lung cancer cells. Oncol Rep. 2016; 35(4): 2053-64.
29. Barranco WT, Eckhert CD. Boric acid inhibits human prostate cancer cell proliferation. Cancer Lett. 2004; 216(1): 21-9.
30. Gallardo-Williams MT, Chapin RE, King PE, Moser GJ, Goldsworthy TL, Morrison JP, et al. Boron supplementation inhibits the growth and local expression of IGF-1 in human prostate adenocarcinoma (LNCaP) tumors in nude mice. Toxicol Pathol. 2004; 32(1): 73-8.
31. Sevimli M, Bayram D, Özgöçmen M, Armağan I, Semerci Sevimli T. Boric acid suppresses cell proliferation by TNF signaling pathway mediated apoptosis in SW-480 human colon cancer line. J Trace Elem Med Biol. 2022; 71: 126958.
32. Cabus U, Secme M, Kabukcu C, Cil N, Dodurga Y, Mete G, Fenkci IV. Boric acid as a promising agent in the treatment of ovarian cancer: Molecular mechanisms. Gene. 2021; 796-7: 145799. https://doi.org/10.1016/j.gene.2021.145799