Bcl2L12 with a BH3-like domain in regulating apoptosis and TMZ-induced autophagy: A prospective combination of ABT-737 and TMZ for treating glioma

Abstract

Abstract. Bcl2L12 as a new member of the Bcl2 family, which contains a BH2 domain and shares a lower amino acid similarity with other Bcl2 family proteins. Bcl2L12 is reported to be involved in apoptosis regulation, but this role remains controversial in different cancer type. Temozolomide (TMZ) is currently used to intervene glioma multiforme (GBM), but an acquired chemotherapeutic resistance maybe occurred due to undesired autophagy. Previous studies uncovered that Bcl2L12 may interact with Bcl-xL and may harbor a BH3-like domain. Therefore, we investigated whether this BH3-like domain is responsible for the Bcl2L12 anti-apoptotic property. Moreover, we tested whether ABT-737, a BH3 mimetic agent, can be combined with TMZ to treat GBM. We aligned Bcl2L12 with Bcl2 family members, compared interacting pattern of BH3 domain and their protein 3D structure. We identified that Bcl2L12 interacts with Bcl-xL and Bcl2 in yeast two-hybrid system. Bcl2L12 192-220 was a minimal region for Bcl2L12-Bcl-xL interaction. Five-point mutations with respect to hydrophobic and charge residues were generated to test whether they are the key residue of BH3-like domain. Our data showed that both h1 (L213) and h2 residue (L217) are essential for Bcl2L12 interacting with Bcl2 family proteins. Ectopically expressed h1 or h2 mutant in U87MG cell line resulted in reactivation of cleaved-PARP, caspase-3 and cytochrome c releasing compared to Bcl2L12 wt group. Implementing ABT-737 combined with TMZ provided a superior effect on apoptosis induction in Bcl2L12 wt group, which effectively reactivated apoptotic markers. Altogether, our findings indicated that Bcl2L12 retains a BH3-like domain, which is important for the Bcl2L12 anti-apoptotic property and TMZ-induced autophagy. Our results basically support the idea of using ABT-737 to counteract the anti-apoptotic role of Bcl2L12 and sensitize drug response of the GBM cells to TMZ.

Long Noncoding RNA LOC100129973 Suppresses Apoptosis by Targeting miR-4707-5p and miR-4767 in Vascular Endothelial Cells

“…For further exploring the possible molecular mechanism of miR-4707-5p and miR-4767 in promoting apoptosis, we predicated the target genes of miR-4707-5p and miR-4767 by miRDB, Targetscan and DIANA LAB. Among these potential targets, we concentrated on Apoptosis Inhibitor 5 (API5) and BCL2 like 2 (BCL2L12) , both of which inhibit cell apoptosis 30 31 32 33 . By using RNAhybrid software, we found that 3′UTR of API5 contained the miR-4707-5p -prediction binding sites with the highest score.…”

Targeting autophagy to sensitive glioma to temozolomide treatment

“…As mentioned earlier, antiapoptotic Bcl-2 family members, such as Bcl2L12, suppress both apoptosis and autophagy, and they are of major importance for therapy resistance of malignant gliomas [ 110 ]. The deregulation of Bcl2 family proteins mostly contributes to apoptosis evasion, suggesting that the inhibition of Bcl2 proteins is one of the most promising new approaches to targeted cancer therapy [ 111 ].…”

“…The deregulation of Bcl2 family proteins mostly contributes to apoptosis evasion, suggesting that the inhibition of Bcl2 proteins is one of the most promising new approaches to targeted cancer therapy [ 111 ]. The Bcl2 inhibitor ABT-737 could counteract the anti-apoptotic role of Bcl2L12 and sensitize drug response of GBM cells to TMZ [ 110 ]. In addition, the pan-Bcl2 inhibitor (−)-gossypol efficiently potentiates caspase-independent autophagic cell death in apoptosis-resistant malignant glioma cells, and it further augments the action of TMZ.…”

Targeting intrinsic apoptosis and other forms of cell death by BH3-mimetics in glioblastoma

“…Aside from radiation, the alkylating agent Temozolomide is another key stone for glioblastoma therapy. The combination treatment of ABT-737 and Temozolomide was successfully tested in model systems of glioblastoma [18] as well as in other tumor entities, such as melanoma. In further studies, combination therapies including ABT-737 were extended toward other targeted therapeutics.…”