Inhibiting Bcl-2 via its BH4 domain in DLBCL cancers to provoke pro-apoptotic Ca2+ signaling

  • Martijn Kerkhofs KU Leuven


Some DLBCL cancers are sensitized to programmed cell death at the ER by upregulation of the IP3R2. These cancers express Bcl-2 in abundance to prevent pro-apoptotic IP3R2-mediated Ca2+ signaling. BIRD-2 (Bcl-2/IP3R Disruptor-2) is a newly developed peptide that disrupts the complex of Bcl-2 and the IP3R, thereby provoking toxic Ca2+ signaling. However, the exact working mechanism of this peptide has not been characterized. We report a possible role for the mitochondria as downstream effectors of BIRD-2-induced cell death and validated a calcein-AM/CoCl2 staining to assess mPTP opening in response to BIRD-2.


1. Elmore S. Apoptosis: a review of programmed cell death. Toxicol Pathol. 2007;35(4):495–516.

2. Certo M, Del Gaizo Moore V, Nishino M, Wei G, Korsmeyer S, Armstrong SA, et al., Mitochondria primed by death signals determine cellular addiction to antiapoptotic BCL-2 family members. Cancer Cell. 2006;9(5):351–65.

3. Yip KW, Reed JC. Bcl-2 family proteins and cancer. Oncogene. 2008;27(50):6398–406.

4. Rong Y-P, Bultynck G, Aromolaran AS, Zhong F, Parys JB, De Smedt H, et al. The BH4 domain of Bcl-2 inhibits ER calcium release and apoptosis by binding the regulatory and coupling domain of the IP3 receptor. Proc Natl Acad Sci U S A. 2009;106(34):14397–402.

5. Rizzuto R, De Stefani D, Raffaello A, Mammucari C. Mitochondria as sensors and regulators of calcium signalling. Nat Rev Mol Cell Biol. 2012;13(9):566–78.

6. Mikoshiba K, Furuichi T, Miyawaki A. Structure and function of IP3 receptors. Semin Cell Biol. 1994;5(4):273–81.

7. Patron M, Checchetto V, Raffaello A, Teardo E, Vecellio Reane D, Mantoan M, et al. MICU1 and MICU2 Finely Tune the Mitochondrial Ca2+ Uniporter by Exerting Opposite Effects on MCU Activity. Mol Cell. 2014;53(5):726–37.

8. Akl H, Monaco G, La Rovere R, Welkenhuyzen K, Kiviluoto S, Vervliet T, et al. IP3R2 levels dictate the apoptotic sensitivity of diffuse large B-cell lymphoma cells to an IP3R-derived peptide targeting the BH4 domain of Bcl-2. Cell Death Dis. 2013;4:e632.

9. Zhong F, Harr MW, Bultynck G, Monaco G, Parys JB, De Smedt H, et al. Induction of Ca2+-driven apoptosis in chronic lymphocytic leukemia cells by peptide-mediated disruption of Bcl-2–IP3 receptor interaction. Blood. 2011;117(10):2924–34.

10. Bonora M, Pinton P. The mitochondrial permeability transition pore and cancer: molecular mechanisms involved in cell death. Front Oncol. 2014;4:302.

11. Halestrap AP, Pasdois P. The role of the mitochondrial permeability transition pore in heart disease. Biochim Biophys Acta BBA - Bioenerg. 2009;1787(11):1402–15.

12. Monaco G, Decrock E, Akl H, Ponsaerts R, Vervliet T, Luyten T, et al. Selective regulation of IP3-receptor-mediated Ca2+ signaling and apoptosis by the BH4 domain of Bcl-2 versus Bcl-Xl. Cell Death Differ. 2012;19(2):295–309.

13. Tan W. VDAC blockage by phosphorothioate oligonucleotides and its implication in apoptosis. Biochim Biophys Acta. 2012;1818(6):1555–61.

14. Abu-Hamad S, Arbel N, Calo D, Arzoine L, Israelson A, Keinan N, et al. The VDAC1 N-terminus is essential both for apoptosis and the protective effect of anti-apoptotic proteins. J Cell Sci. 2009;122(Pt 11):1906–16.

15. Mather MW, Rottenberg H. The inhibition of calcium signaling in T lymphocytes from old mice results from enhanced activation of the mitochondrial permeability transition pore. Mech Ageing Dev. 2002;123(6):707–24.

Author Biography

Martijn Kerkhofs, KU Leuven
Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine,
How to Cite
KERKHOFS, Martijn. Inhibiting Bcl-2 via its BH4 domain in DLBCL cancers to provoke pro-apoptotic Ca2+ signaling. Student Undergraduate Research E-journal!, [S.l.], v. 1, nov. 2015. ISSN 2468-0443. Available at: <>. Date accessed: 21 feb. 2019.