Effective tumor cell abrogation via Venetoclax-mediated BCL-2 inhibition in KMT2A-rearranged acute B-lymphoblastic leukemia

Trilobatin attenuates cerebral ischaemia/reperfusion-induced blood-brain barrier dysfunction by targeting matrix metalloproteinase 9: The legend of a food additive

BACKGROUND AND PURPOSE

Blood-brain barrier (BBB) breakdown is one of the crucial pathological changes of cerebral ischaemia-reperfusion (I/R) injury. Trilobatin (TLB), a naturally occurring food additive, exerts neuroprotective effects against cerebral I/R injury as demonstrated in our previous study. This study was designed to investigate the effect of TLB on BBB disruption after cerebral I/R injury.

EXPERIMENTAL APPROACH

Rats with focal cerebral ischaemia caused by transient middle cerebral artery occlusion were studied along with brain microvascular endothelial cells and human astrocytes to mimic BBB injury caused by oxygen and glucose deprivation/reoxygenation (OGD/R).

KEY RESULTS

The results showed that TLB effectively maintained BBB integrity and inhibited neuronal loss following cerebral I/R challenge. Furthermore, TLB increased tight junction proteins including ZO-1, Occludin and Claudin 5, and decreased the levels of apolipoprotein E (APOE) 4, cyclophilin A (CypA) and phosphorylated nuclear factor kappa B (NF-κB), thereby reducing proinflammatory cytokines. TLB also decreased the Bax/Bcl-2 ratio and cleaved-caspase 3 levels along with a reduced number of apoptotic neurons. Molecular docking and transcriptomics predicted MMP9 as a prominent gene evoked by TLB treatment. The protective effects of TLB on cerebral I/R-induced BBB breakdown was largely abolished by overexpression of MMP9, and the beneficial effects of TLB on OGD/R-induced loss of BBB integrity in human brain microvascular endothelial cells and astrocyte co-cultures was markedly reinforced by knockdown of MMP9.

CONCLUSIONS AND IMPLICATIONS

Our findings reveal a novel property of TLB: preventing BBB disruption following cerebral I/R via targeting MMP9 and inhibiting APOE4/CypA/NF-κB axis.

Acute lymphoblastic leukemia in young adults: which treatment?

Despite improvements in survival among pediatric patients with acute lymphoblastic leukemia (ALL), survival outcomes for adolescents and young adults (AYAs) with ALL have lagged. The reasons for the inferior outcomes among AYAs are multifactorial, each presenting unique challenges and requiring novel solutions. First, adverse disease biology is more common among AYAs with ALL. Ongoing trials are investigating novel approaches to treatment, such as incorporating JAK inhibitors for Philadelphia chromosome-like ALL, menin inhibitors for KMT2A-rearranged ALL, and BCL2/BCLXL inhibition for T-cell ALL. Poorer adherence to therapy also impedes improvements in survival outcomes for AYAs with ALL, but early data suggest that technology, both for monitoring and interventions, may be useful in increasing adherence among this population. Finally, better access to clinical trials and collaboration between pediatric and adult centers is critical in advancing the care of AYAs with ALL. Significant improvements have been made over the past decade, but recognizing, understanding, and addressing each of these unique challenges provides hope that the outcomes for AYAs will continue to improve even further.

Knockdown of MEF2D inhibits the development and progression of B-cell acute lymphoblastic leukemia

Background

Myocyte enhancer factor 2D (MEF2D) is involved in the progression of various malignant tumors. However, its impact on B-cell acute lymphoblastic leukemia (B-ALL) has not been elucidated.

Methods

In this study, the expression level of MEF2D in B-ALL patients was validated through the Gene Expression Omnibus (GEO) database and clinical specimens. MEF2D-knockdown B-ALL cell lines were constructed by lentivirus transfection, and the effects of MEF2D on the viability, apoptosis, cycle progression, and drug sensitivity of B-ALL cells were verified by Cell Counting Kit-8 (CCK-8) and flow cytometry (FCM). The effect of MEF2D on the proliferation of B-ALL cells in vivo was verified via the construction of a xenograft mouse model. The mechanism of MEF2D regulating B-ALL cells was explored by RNA sequencing analysis, quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blotting, and immunohistochemical (IHC).

Results

In this study, overexpression of MEF2D was observed in B-ALL patients and was remarkably correlated to disease progression in ALL patients. The knockdown of MEF2D expression suppressed cell viability, induced cell apoptosis, blockaded cell cycle progression, enhanced drug sensitivity of B-ALL cells in vitro, and reduced the tumor load in vivo. Furthermore, mechanistic studies revealed that MEF2D knockdown downregulated the expression of the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)-protein kinase B (AKT) signaling pathway.

Conclusions

Our research demonstrated that MEF2D was markedly expressed in B-ALL. MEF2D knockdown inhibited cancer progression of B-ALL both in vitro and in vivo, which may be related to the downregulation of the PI3K-AKT signaling pathway. The data suggest that MEF2D plays a vital role in the process of tumorigenesis and may be a potential novel target for B-ALL therapy.

Combined BCL-2 and PI3K/AKT Pathway Inhibition in KMT2A-Rearranged Acute B-Lymphoblastic Leukemia Cells

Numerous hematologic neoplasms, including acute B-lymphoblastic leukemia (B-ALL), are characterized by overexpression of anti-apoptotic BCL-2 family proteins. Despite the high clinical efficacy of the specific BCL-2 inhibitor venetoclax in acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL), dose limitation and resistance argue for the early exploration of rational combination strategies. Recent data indicated that BCL-2 inhibition in B-ALL with KMT2A rearrangements is a promising intervention option; however, combinatorial approaches have not been in focus so far. The PI3K/AKT pathway has emerged as a possible target structure due to multiple interactions with the apoptosis cascade as well as relevant dysregulation in B-ALL. Herein, we demonstrate for the first time that combined BCL-2 and PI3K/AKT inhibition has synergistic anti-proliferative effects on B-ALL cell lines. Of note, all tested combinations (venetoclax + PI3K inhibitors idelalisib or BKM-120, as well as AKT inhibitors MK-2206 or perifosine) achieved comparable anti-leukemic effects. In a detailed analysis of apoptotic processes, among the PI3K/AKT inhibitors only perifosine resulted in an increased rate of apoptotic cells. Furthermore, the combination of venetoclax and perifosine synergistically enhanced the activity of the intrinsic apoptosis pathway. Subsequent gene expression studies identified the pro-apoptotic gene BBC3 as a possible player in synergistic action. All combinatorial approaches additionally modulated extrinsic apoptosis pathway genes. The present study provides rational combination strategies involving selective BCL-2 and PI3K/AKT inhibition in B-ALL cell lines. Furthermore, we identified a potential mechanistic background of the synergistic activity of combined venetoclax and perifosine application.