Treating adults with acute lymphocytic leukemia: new pharmacotherapy options

Novel bioactive hybrid Celecoxib-HDAC Inhibitor, induces apoptosis in human acute lymphoblastic leukemia cells

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children. Here, we exploited the synergy between histone deacetylase inhibitors (HDACi) and cyclooxygenase 2 (COX-2) inhibitors by generating and testing a series of hybrid Celecoxib-HDAC inhibitors (selenium-containing analogues of Celecoxib) on ALL cells, of which compound 11 exhibited significant inducement to kill NALM6 cells with an average IC50 of 9.95 ± 0.44 μM compared with control Celecoxib at 28.58 ± 1.44 μM and inhibited NALM6 cells growth via the inhibition of the cell cycle in G2 phase. Furthermore, compound 11 induced apoptosis by activating PARP cleavage. Taken together, compound 11 possessed the potential to be developed further as a chemotherapeutic agent for ALL.

Targeting the lncRNA DUXAP8/miR-29a/PIK3CA Network Restores Doxorubicin Chemosensitivity via PI3K-AKT-mTOR Signaling and Synergizes With Inotuzumab Ozogamicin in Chemotherapy-Resistant B-Cell Acute Lymphoblastic Leukemia

Purpose

This study aimed to determine the expression profiles of long non-coding RNA (lncRNA), microRNA (miRNA), and mRNA in chemotherapy-resistant B-cell acute lymphoblastic leukemia (B-ALL).

Methods

LncRNA, miRNA, and mRNA profiles were assessed by RNA-seq in diagnostic bone marrow samples from 6 chemotherapy-resistant and 6 chemotherapy-sensitive B-ALL patients. The lncRNA DUXAP8/miR-29a/PIK3CA signaling network was identified as the most dysregulated in chemoresistant patient samples, and its effect on cellular phenotypes, PI3K-AKT-mTOR signaling, and chemosensitivity of doxorubicin (Dox)-resistant Nalm-6 (N6/ADR), and Dox-resistant 697 (697/ADR) cells were assessed. Furthermore, its synergy with inotuzumab ozogamicin treatment was investigated.

Results

1,338 lncRNAs, 75 miRNAs, and 1620 mRNAs were found to be dysregulated in chemotherapy-resistant B-ALL in comparison to chemotherapy-sensitive B-ALL patient samples. Through bioinformatics analyses and RT-qPCR validation, the lncRNA DUXAP8/miR-29a/PIK3CA network and PI3K-AKT-mTOR signaling were identified as significantly associated with B-ALL chemotherapy resistance. In N6/ADR and 697/ADR cells, LncRNA DUXAP8 overexpression and PIK3CA overexpression induced proliferation and inhibited apoptosis, and their respective knockdowns inhibited proliferation, facilitated apoptosis, and restored Dox chemosensitivity. MiR-29a was shown to affect the lncRNA DUXAP8/PIK3CA network, and luciferase reporter gene assay showed direct binding between lncRNA DUXAP8 and miR-29a, as well as between miR-29a and PIK3CA. Targeting lncRNA DUXAP8/miR-29a/PIK3CA network synergized with inotuzumab ozogamicin's effect on N6/ADR and 697/ADR cells.

Conclusion

Targeting the lncRNA DUXAP8/miR-29a/PIK3CA network not only induced an apoptotic effect on Dox-resistant B-ALL and restored Dox chemosensitivity via PI3K-AKT-mTOR signaling but also showed synergism with inotuzumab ozogamicin treatment.

Why Do Children with Acute Lymphoblastic Leukemia Fare Better Than Adults?

It is a new and exciting time for acute lymphoblastic leukemia (ALL). While nearly 50 years ago, only one in nine children with ALL survived with chemotherapy, nowadays nearly 90% of children have a chance of long-term survival. Adults with ALL, as well as the special category of adolescents and young adult (AYA) patients, are catching up with the new developments seen in children, but still their prognosis is much worse. A plethora of factors are regarded as responsible for the differences in treatment response, such as age, ethnicity, disease biology, treatment regimens and toxicities, drug tolerance and resistance, minimal residual disease evaluation, hematopoietic stem cell transplantation timing and socio-economic factors. Taking these factors into account, bringing pediatric-like protocols to adult patient management and incorporating new agents into frontline treatment could be the key to improve the survival rates in adults and AYA.

D,L-Methadone causes leukemic cell apoptosis via an OPRM1-triggered increase in IP3R-mediated ER Ca2+ release and decrease in Ca2+ efflux, elevating [Ca2+]i

The search continues for improved therapy for acute lymphoblastic leukemia (aLL), the most common malignancy in children. Recently, d,l-methadone was put forth as sensitizer for aLL chemotherapy. However, the specific target of d,l-methadone in leukemic cells and the mechanism by which it induces leukemic cell apoptosis remain to be defined. Here, we demonstrate that d,l-methadone induces leukemic cell apoptosis through activation of the mu1 subtype of opioid receptors (OPRM1). d,l-Methadone evokes IP3R-mediated ER Ca²⁺ release that is inhibited by OPRM1 loss. In addition, the rate of Ca²⁺ extrusion following d,l-methadone treatment is reduced, but is accelerated by loss of OPRM1. These d,l-methadone effects cause a lethal rise in [Ca²⁺]_i that is again inhibited by OPRM1 loss, which then prevents d,l-methadone-induced apoptosis that is associated with activation of calpain-1, truncation of Bid, cytochrome C release, and proteolysis of caspase-3/12. Chelating intracellular Ca²⁺ with BAPTA-AM reverses d,l-methadone-induced apoptosis, establishing a link between the rise in [Ca²⁺]_i and d,l-methadone-induced apoptosis. Altogether, our findings point to OPRM1 as a specific target of d,l-methadone in leukemic cells, and that OPRM1 activation by d,l-methadone disrupts IP3R-mediated ER Ca²⁺ release and rate of Ca²⁺ efflux, causing a rise in [Ca²⁺]_i that upregulates the calpain-1-Bid-cytochrome C-caspase-3/12 apoptotic pathway.

LukS-PV induces apoptosis in acute myeloid leukemia cells mediated by C5a receptor

LukS‐PV is one of the two components of Panton‐Valentine leucocidin (PVL). Our previous study showed that LukS‐PV can induce apoptosis in human acute myeloid leukemia (AML) THP‐1 and HL‐60 cells. C5aR (C5a receptor) is the receptor for PVL, but whether C5aR plays a key role in LukS‐PV induced apoptosis is unclear. The aim of this study was to establish whether C5aR plays a physiological role in apoptosis of leukemia cells induced by LukS‐PV. We investigated the role of C5aR in leukemia cell apoptosis induced by LukS‐PV by pretreatment of THP‐1 and HL‐60 cells with C5aR antagonist and transfection to knockdown C5aR in THP‐1 cells or overexpress C5aR in Jurkat cells before treatment with LukS‐PV. Cell apoptosis was analyzed by staining with Annexin V/propidium iodide or Annexin V‐PE/7‐AAD. Mitochondrial membrane potential (MMP) was determined using JC‐1 dye. The expression of apoptosis‐associated genes and proteins was identified by qRT‐polymerase chain reaction and Western blotting analysis, respectively. As the C5aR antagonist concentration increased, the rate of apoptosis induced by LukS‐PV decreased, the MMP increased, and expression of pro‐apoptotic Bax and Bak genes and proteins was downregulated while that of anti‐apoptotic Bcl‐2 and Bcl‐x genes and proteins was upregulated. Knockdown of C5aR also decreased LukS‐PV–induced THP‐1 cell apoptosis. LukS‐PV did not induce apoptosis of Jurkat cells, which have no endogenous C5aR expression; however, LukS‐PV did induce apoptosis in Jurkat cells after overexpression of C5aR. Correspondingly, the MMP decreased and Bax and Bak were upregulated while Bcl‐2 and Bcl‐x were downregulated. LukS‐PV can induce apoptosis in AML cells by targeting C5aR. C5aR may be a potential therapeutic target for AML and LukS‐PV is a candidate targeted drug for the treatment of AML.

Efficacy and safety of bispecific T-cell engager blinatumomab and the potential to improve leukemia-free survival in B-cell acute lymphoblastic leukemia

INTRODUCTION

Immunotherapy is a promising modality of treatment of neoplastic diseases, including acute lymphoblastic leukemia (ALL). The CD19/CD3-bispecific T cell-engaging (BiTE®) monoclonal antibody blinatumomab can transiently bind cytotoxic T cells to CD19⁺ target B cells of ALL inducing their serial lysis. Areas covered: This review focuses on the efficacy and safety of blinatumomab used for the treatment of relapsed/refractory (R/R) ALL and minimal residual disease (MRD)-positive B-cell precursor (BCP) ALL in adults and children, as well as the future prospects of this drug in the treatment of ALL. Expert commentary: Blinatumomab has demonstrated encouraging response rates in MRD-positive and R/R in adults with Philadelphia chromosome-positive and -negative ALL, as well as in children with R/R ALL. Blinatumomab has a favorable safety profile, although reversible CNS events and cytokine release syndrome can occur. Ongoing trials in ALL incorporate blinatumomab in the first line therapy of BCP ALL in combination with chemotherapy, targeted therapies or other immunotherapies with the aim of increasing the depth of the remission and decreasing the probability of relapse.