The immunophenotype of 177 adults with acute myeloid leukemia: proposal of a prognostic score

Inhibition of JAK/STAT3 Expression by Acute Myeloid Leukemia-Targeted Nanoliposome for Chemotherapy Enhancement

Acute myeloid leukemia (AML) is a relatively common malignant hematological disease whose development is mostly associated with abnormal activation of the JAK/STAT3 signaling pathway. Our previous study revealed that SAR317461, a novel JAK2/STAT3 inhibitor, can effectively inhibit the activation of the JAK2/STAT3 signaling pathway and has significant damaging and pro-apoptotic effects on AML cell lines. This project aims to build upon our prior research to enhance the application of SAR317461 in AML. The surface modification of liposomes with the CD34 antibody, along with the inclusion of the SAR317461 and cytarabine (a common AML chemotherapeutic agent), is observed. Due to the high expression of CD34 on the surface of AML cells, the nanoliposome could target AML cells specifically, further achieving an effective treatment for AML through the synergistic effect of JAK2/STAT3 inhibitors and chemotherapeutic agents. The implementation of this project will provide more theoretical support and ideas for the clinical application of JAK/STAT3 inhibitors in malignant tumors and for overcoming chemotherapy resistance.

Lanthanide-doped nanoparticles conjugated with an anti-CD33 antibody and a p53-activating peptide for acute myeloid leukemia therapy

Roughly one third of all human cancers are attributable to the functional inhibition of the tumor suppressor protein p53 by its two negative regulators MDM2 and MDMX, making dual-specificity peptide antagonists of MDM2 and MDMX highly attractive drug candidates for anticancer therapy. Two pharmacological barriers, however, remain a major obstacle to the development of peptide therapeutics: susceptibility to proteolytic degradation in vivo and inability to traverse the cell membrane. Here we report the design of a fluorescent lanthanide oxyfluoride nanoparticle (LONp)-based multifunctional peptide drug delivery system for potential treatment of acute myeloid leukemia (AML) that commonly harbors wild type p53, high levels of MDM2 and/or MDMX, and an overexpressed cell surface receptor, CD33. We conjugated to LONp via metal-thiolate bonds a dodecameric peptide antagonist of both MDM2 and MDMX, termed PMI, and a CD33-targeted, humanized monoclonal antibody to allow for AML-specific intracellular delivery of a stabilized PMI. The resultant nanoparticle antiCD33-LONp-PMI, while nontoxic to normal cells, induced apoptosis of AML cell lines and primary leukemic cells isolated from AML patients by antagonizing MDM2 and/or MDMX to activate the p53 pathway. Fluorescent antiCD33-LONp-PMI also enabled real-time visualization of a series of apoptotic events in AML cells, proving a useful tool for possible disease tracking and treatment response monitoring. Our studies shed light on the development of antiCD33-LONp-PMI as a novel class of antitumor agents, which, if further validated, may help targeted molecular therapy of AML.

SGN-CD33A: a novel CD33-targeting antibody-drug conjugate using a pyrrolobenzodiazepine dimer is active in models of drug-resistant AML

Outcomes in acute myeloid leukemia (AML) remain unsatisfactory, and novel treatments are urgently needed. One strategy explores antibodies and their drug conjugates, particularly those targeting CD33. Emerging data with gemtuzumab ozogamicin (GO) demonstrate target validity and activity in some patients with AML, but efficacy is limited by heterogeneous drug conjugation, linker instability, and a high incidence of multidrug resistance. We describe here the development of SGN-CD33A, a humanized anti-CD33 antibody with engineered cysteines conjugated to a highly potent, synthetic DNA cross-linking pyrrolobenzodiazepine dimer via a protease-cleavable linker. The use of engineered cysteine residues at the sites of drug linker attachment results in a drug loading of approximately 2 pyrrolobenzodiazepine dimers per antibody. In preclinical testing, SGN-CD33A is more potent than GO against a panel of AML cell lines and primary AML cells in vitro and in xenotransplantation studies in mice. Unlike GO, antileukemic activity is observed with SGN-CD33A in AML models with the multidrug-resistant phenotype. Mechanistic studies indicate that the cytotoxic effects of SGN-CD33A involve DNA damage with ensuing cell cycle arrest and apoptotic cell death. Together, these data suggest that SGN-CD33A has CD33-directed antitumor activity and support clinical testing of this novel therapeutic in patients with AML.

Cytoplasmic expression of nucleophosmin accurately predicts mutation in the nucleophosmin gene in patients with acute myeloid leukemia and normal karyotype

Mutations in the nucleophosmin (NPM1) exon 12 resulting in delocalization of NPM1 into the cytoplasm occur in 50% to 60% of acute myeloid leukemia cases with a normal karyotype (AML-NK). As recent studies suggest such patients have a favorable prognosis and there are discordant reports of the immunohistochemical detection of cytoplasmic NPM1 (NPMc+) for predicting NPM1 gene mutations, we correlated the immunohistochemical detection of NPMc+, NPM1 gene mutations, and prognosis in 57 cases of AML-NK. All 31 NPMc+ cases (54% of total) had NPM1 mutations, but none of the 26 nucleus-restricted (NPMc-) cases (46% of total) had NPM1 mutations (P < .0001). NPM1 mutations were correlated with FLT3-internal tandem duplication (ITD) (P = .0062), absence of CD34 (P = .0001), and absence of CD7 (P = .041). There was a favorable survival outcome in AML-NK cases that were NPM1 mutated and FLT3-ITD nonmutated. Our data confirm that cytoplasmic NPM1 immunoreactivity predicts NPM1 mutations and warrants inclusion in the routine diagnostic and prognostic workup of AML.