Spatial Stochastic Model of the Pre-B Cell Receptor

Characterizing the Mechanism of NE and P3 Cross-Presentation in B Cell-Acute Lymphoblastic Leukemia

Lack of CD24 Antigen Expression in B-Lineage Acute Lymphoblastic Leukemia Is Associated With Intrinsic Radiation Resistance of Primary Clonogenic Blasts

Britannin, a Sesquiterpene Lactone isolated from Inula aucheriana, has recently gained attraction in the therapeutic fields due to its anti-tumor properties. This study was designed to evaluate the effect of this agent on Acute Lymphoblastic Leukemia (ALL) cell lines, either as a monotherapy or in combination with Vincristine (VCR). To determine the anti-leukemic effects of Britannin on ALL-derived cell lines and suggest a mechanism of action for the agent, we used MTT assay, Annexin-V/PI staining, ROS assay, and real-time PCR analysis. Moreover, by using a combination index (CI), we evaluated the synergistic effect of Britannin on Vincristine. We found that unlike normal Peripheral Blood Mononuclear Cells (PBMCs) and L929 cells, Britannin reduced the viability of NALM-6, REH, and JURKAT cells. Among tested cells, NALM-6 cells had the highest sensitivity to Britannin, and this agent was able to induce p21/p27-mediated G1 cell cycle arrest and Reactive Oxygen Specious (ROS)-mediated apoptotic cell death in this cell line. When NALM-6 cells were treated with Nacetyl-L-Cysteine (NAC), a scavenger of ROS, Britannin could induce neither apoptosis nor reduce the survival of the cells suggesting that the cytotoxic effect of Britannin is induced through ROS-dependent manner. Moreover, we found that a low dose of Britannin enhanced the effect of Vincristine in NALM-6 cells by inducing apoptotic cell death via altering the expression of apoptotic-related genes. Overall, our results proposed a mechanism for the cytotoxic effect of Britannin, either as a single agent or in combination with Vincristine, in NALM-6 cells.

LincRNA Expression Discriminates Cytogenetic Subtypes In B-Lymphoblastic Leukemia and Plays a Functional Role In Leukemia Cell Survival

In Vitro and In Vivo Activity of Topotecan Against Human B-Lineage Acute Lymphoblastic Leukemia Cells

Distinct MiR-126 Expression Describes a Non-Genetic but Functional Intra-Tumoral Heterogeneity in Primary Human B-ALL and Can be Prospectively Used to Identify Aggressive Subclones in NSG Mice

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.

Next-generation sequencing technology has improved molecular genetic analysis, and many molecular genetic studies have been utilized for diagnostic classification, risk stratification, and prognosis prediction of acute lymphoblastic leukemia (ALL). Inactivation of neurofibromin or Nf1, a protein derived from the NF1 gene, causes Ras pathway regulation failure, which is related to leukemogenesis. Pathogenic variants of the NF1 gene in B-cell lineage ALL are uncommon, and in this study, we reported a pathogenic variant that is not registered in any public database. The patient diagnosed with B-cell lineage ALL had no clinical symptoms of neurofibromatosis. Studies on the biology, diagnosis, and treatment of this uncommon disease, as well as other related hematologic neoplasms, such as acute myeloid leukemia and juvenile myelomonocytic leukemia, were reviewed. Biological studies included epidemiological differences among age intervals and pathways for leukemia, such as the Ras pathway. Diagnostic studies included cytogenetic, FISH, and molecular tests for leukemia-related genes and ALL classification, such as Ph-like ALL or BCR-ABL1-like ALL. Treatment studies included pathway inhibitors and chimeric antigen cell receptor T-cells. Resistance mechanisms related to leukemia drugs were also investigated. We believe that these literature reviews will enhance medical care for the uncommon diagnosis of B-cell lineage ALL.

Acute leukemias are the most common malignant diseases in childhood. The aims of this retrospective cohort study were to investigate the frequency of cytogenetic abnormalities in acute pediatric leukemia; the correlation between cytogenetic abnormalities and 5-year survival; and the correlation between cytogenetic abnormalities and clinical and laboratory features. We included 105 patients; acute lymphoblastic leukemia (ALL) had 80.9% patients, B-cell lineage ALL (B-ALL) 84.7% of them, and T-cell lineage (T-ALL) 15.3%. The overall 5-year survival for B-ALL was 85.9% and for T-ALL was 84.6%. The most common cytogenetic abnormalities in patients with B-ALL were t(12;21)(p13.2;q22.1); ETV6-RUNX1 with 22.2% and hyperdiploidy with 19.4%. Our survival analysis showed that t(12;21)(p13.2;q22.1); ETV6-RUNX1 and t(1;19)(q23;p13.3); TCF3-PBX1 had the best 5-year survival with 100% of patients surviving, whereas t(v;11q23.3); KMT2A rearranged had the worst 5-year survival of just 33.3% of patients surviving after 5 years. We found no difference in 5-year survival in B-ALL when comparing clinical features. Acute myelogenous leukemia had 20 patients with 70.6% 5-year survival. The most common cytogenetic abnormality in acute myelogenous leukemia was t(8;21)(q21;q22.1); RUNX1-RUNX1T1 (20%). In conclusion, this study showed the correlation of different cytogenetic abnormalities with 5-year survival in B-ALL patients. Such correlation was not found when comparing clinical features and 5-year survival of patients with B-ALL. This emphasized the significance of cytogenetic analysis in pediatric leukemia.

Acute lymphoblastic leukemia (ALL) is the most common blood cancer of children and the most frequent cause of cancer related death before 20 years of age. Although the survival rate of pediatric patients with ALL is approximately 90% due to innovative chemotherapy regimens, finding treatment options for patients with relapsed/refractory ALL continues to be challenging. The PI3K/AKT/mTOR axis is often constitutively activated in relapse/refractory ALL. For example, loss of the tumor suppressor PTEN leads to hyperactivation of AKT signaling. Despite the importance of PI3K-AKT signaling in ALL, clinically effective treatment strategies to target PI3K-AKT signaling have had limited success. Inhibiting AKT signaling with capivasertib, a first in class pan AKT-inhibitor recently approved for the treatment of ER+ breast cancer, exhibits monotherapy anti-proliferative activity in pediatric T-ALL and B-ALL cell lines. However, only partial anti-proliferative activity was observed from monotherapy capivasertib treatment. To address if the activity of capivasertib in ALL could be improved by combining with other agents, we explored whether addition of the glucocorticoid, dexamethasone, and the Bcl-2 inhibitor, venetoclax could provide better therapeutic benefit in preclinical models of ALL. We conducted a capivasertib centric in vitro combination screen across a panel ALL cell lines. In contrast to monotherapy activities, the combination of capivasertib with dexamethasone and venetoclax showed greater cell killing in 4/5 B-ALL and 3/3 T-ALL cell lines. Interestingly, the combination enhanced antitumoral activity in most ALL cell lines regardless of the presence or absence known PI3K/AKT mutational pathway drivers. Importantly, capivasertib enhanced response to dexamethasone in a subset glucocorticoid refractory ALL cell line models that were insensitive to monotherapy glucocorticoid treatment. To further investigate whether the combination in vitro activity can translate in vivo, combinations of capivasertib, venetoclax and dexamethasone were evaluated in ALL CDX models and a disseminated pediatric PDX of T-ALL harboring known drivers of AKT hyperactivation. Using a clinically relevant dose and schedule of capivasertib, treatment combination groups led to 60% and 70% TGI in the MOLT4 and Karpas-231 xenograft models respectively. Whereas a 20% increase in survival relative to the vehicle group was observed in a disseminated T-ALL PDX model. Taken together, our results provide preclinical evidence for the rational combination of capivasertib, venetoclax and dexamethasone in the treatment of pediatric patients with relapsed/refractory ALL. Citation Format: Brandon Willis, Nadezda Bryan, Justine Roderick-Richardson, Alan Rosen, Lori Chan, Simon T. Barry. AKT inhibitor capivasertib combines with dexamethasone and venetoclax to enhance anti-tumor responses in the preclinical models of childhood acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3951.

Our previous study demonstrated that the dominant-negative Ikaros isoform 6 (Ik6) is overexpressed in Chinese children with newly diagnosed B-acute lymphoblastic leukemia (B-ALL) and is strongly associated with a poor outcome. The purpose of the present study was to further explore the function of Ik6 in B-ALL. The association between Ik6 expression as detected by real-time PCR and efficacy of chemotherapy was evaluated. The effect of the alteration in Ik6 on leukemic cell lines was assessed by in vitro gain-of-function and loss-of-function techniques. PCR analysis showed that Ik6 expression was decreased when patients completed induction chemotherapy and reached complete remission. Ik6 expression was significantly increased when patients suffered relapse. Stable transfection of Ik6 into the Nalm-6 cell line revealed that Ik6 enhanced proliferation of Nalm-6 cells through the promotion of G0/G1-to-S-phase transition and enhanced chemoresistance to chemotherapeutics through anti-apoptotic effects. However, Ik6 expression did not affect the invasion of Nalm-6 cells. In contrast, silencing of Ik6 in Sup-B15 cells significantly inhibited proliferation and increased chemosensitivity. The present study suggests that Ik6 may be a biological marker of chemosensitivity and relapse and Ik6 may provide a potential therapeutic strategy for ALL.

<div>Abstract<p>BH3 mimetic drugs may be useful to treat acute lymphoblastic leukemia (ALL) but the sensitivity of primary tumor cells has not been fully evaluated. Here, B-lineage ALL cell cultures derived from a set of primary tumors were studied with respect to sensitivity to the BH3 mimetics ABT-263 and ABT-199 and to Bcl-2 dependence and function. These ALL cells each expressed high levels of Bcl-2 and exhibited great sensitivity to ABT-263 and ABT-199, which induced rapid apoptotic cell death. BH3 profiling indicated that the ALL cultures were Bcl-2 dependent. Coimmunoprecipitation studies revealed a multifaceted role for Bcl-2 in binding proapoptotic partners including Bax, Bak, Bik, and Bim. ABT-263 disrupted Bcl-2:Bim interaction in cells. Mcl-1 overexpression rendered ALL cells resistant to ABT-263 and ABT-199, with Mcl-1 assuming the role of Bcl-2 in binding Bim. Freshly isolated pediatric ALL blasts also expressed high levels of Bcl-2 and exhibited high sensitivity to Bcl-2 inhibition by the BH3 mimetic compounds. Overall, our results showed that primary ALL cultures were both more sensitive to BH3 mimetics and more uniform in their response than established ALL cell lines that have been evaluated previously. Furthermore, the primary cell model characterized here offers a powerful system for preclinical testing of novel drugs and drug combinations to treat ALL. <i>Cancer Res; 75(7); 1366–75. ©2015 AACR</i>.</p></div>

Targeting the DNA Damage Response Pathway in MLL- rearranged B-Acute Lymphoblastic Leukemias

CD9, a key actor in the dissemination of lymphoblastic leukemia, modulating CXCR4-mediated migration via RAC1 signaling

Next-Generation NAMPT Inhibitors For ALL Identified By Sequential High-Throughput Phenotypic Chemical and Functional Genomic Screens