Metformin exerts a synergistic effect with venetoclax by downregulating Mcl-1 protein in acute myeloid leukemia

Abstract

Background: Recently, one of the specific BH3-mimetics, Venetoclax has been approved by FDA providing new options for newly diagnosed AML patient especially who are unfitted to receive conventional chemotherapy. Though the clinical success of venetoclax has been achieved in clinical outcomes such as complete remission (CR) and overall survival. Acquired resistance to ABT-199 which is induced by the regulation of apoptosis pathway is still an important clinical problem. To this end, the attempt to combine drugs which can reverse the compensatory regulation is urgent. Methods: In three AML cell lines (KG-1, Kasumi-1 and THP-1), the anti-AML effects of the combination of and metformin or the two drugs used alone were compared. CCK8 was used to evaluate the cell viability, and flow cytometry was used to estimate the rate of apoptosis, Western blot method was performed to detect apoptosis-related protein levels. In mice experiments, female BALB/c-nu nude mice were subcutaneously injected with THP-1 cells for subcutaneous tumor formation, and the combined effect of ABT-199 and metformin was tested. The evaluation indicators were tumor size, tumor weight, and Ki67 staining. Mouse body weight and HE staining were detected to evaluate liver damage and adverse drug reactions. Results: Both in vitro and in vivo experiments showed that compared with metformin or ABT-199 alone, the combined use of the two drugs exerts a synergistic effect on promoting apoptosis, thereby producing a strong anti-leukemia effect. Furthermore, after a short incubation time, ABT-199 swiftly increased the expression level of the anti-apoptotic protein Mcl-1, while the combined use of metformin and ABT-199 significantly reduced the level of Mcl-1. Notably, Metformin significantly downregulates the level of Mcl-1 protein by inhibiting its protein production. To less extent, metformin can also downregulate the expression of another anti-apoptotic protein, BCL-xl. Conclusion:Metformin downregulates the expression of anti-apoptotic proteins Mcl-1 and Bcl-xl by inhibiting protein production, and shows a synergistic anti-tumor effect with ABT-199 in acute myeloid leukemia.

Metformin sensitizes AML cells to venetoclax through endoplasmic reticulum stress—CHOP pathway

“…It has been reported that the upregulation of the expression of the anti‐apoptotic protein MCL‐1 caused by venetoclax is one of the main reasons for its drug resistance 44,45 . A previous study reported that metformin sensitizes AML cells to venetoclax by downregulating MCL‐1 46 . However, we observed apoptosis of both Molm13 and THP‐1 AML cells, while metformin alone did not change the expression level of MCL‐1.…”

“…A previous study reported that metformin sensitizes AML cells to venetoclax by downregulating MCL-1. 46 However, we observed apoptosis of both Molm13 and THP-1 AML cells, while metformin alone not change the expression level of MCL-1. This finding suggests that there might be other unreported mechanisms triggering apoptosis in AML cells treated with the combination of metformin and venetoclax.…”

Metformin and Thymoquinone Synergistically Inhibit Proliferation of Imatinib-Resistant Human Leukemic Cells

“…In LAMA cells resistant to imatinib therapy, 25 mM metformin monotherapy or a ten times decreased concentration (2.5 mM) of metformin in combination with 5 µM TQ reduced levels of Mcl-1 to 0.53 and 0.60 compared to control, respectively ( Figure 4B ). Inhibition of Mcl-1 by metformin was previously shown in AML cells ( Zhou et al, 2021 ) and other tumors ( Park et al, 2018 ; Ye et al, 2020 ; Chen et al, 2021 ).…”

Ceramide nanoliposomes augment the efficacy of venetoclax and cytarabine in models of acute myeloid leukemia

“…Venetoclax-dependent upregulation of anti-apoptotic proteins such as Mcl-1, as well as Ara-Cupregulation of drug-resistant kinases that induce DNA repair and promote survival, such as Chk-1 and cdc25C, has been described. 23 Moreover, targeting Chk1 24,25 and Mcl-1 26,27 have been shown to improve responses to Ara-C and venetoclax, respectively. In this regard, it is worth noting that CNL treatment of venetoclax-resistant MV4-11 cells induced a more profound decrease in Mcl-1 and phospho-Chk1 levels than in drug-naïve MV4-11 (Figure 4C).…”