Activity of eftozanermin alfa plus venetoclax in preclinical models and patients with acute myeloid leukemia

Natural pyrethrins induced developmental toxicity of zebrafish swim bladder in vivo and genotoxicity of lung cells in vitro

Natural pyrethrins (NPs) are insecticidal compounds isolated and extracted from pyrethrum flowers and are primarily use to control sanitary pests. The lungs become the main target after exposure, and its use may pose potential hazards to respiratory health. Therefore, in this paper, the toxic effects of NPs on human lung cells A549 were investigated and the risk of respiratory toxicity of NPs was studied using zebrafish swim bladder as a model. The results showed that NPs induced cytotoxicity, caused oxidative DNA damage and triggered mitochondria-mediated apoptosis. In addition, exposure to NPs decreased zebrafish embryo survival, hatchability, and heartbeat, and may inhibit normal swim bladder development by disrupting Wnt and Hedgehog signaling pathways. In conclusion, our results suggest that NPs can induce cytotoxicity in A549 in vitro and developmental toxicity in zebrafish in vivo. This study provides a conceptual basis for understanding the mechanisms of toxicity of NPs and assessing respiratory health risks in humans.

Cytoplasmic TP53INP2 acts as an apoptosis partner in TRAIL treatment: the synergistic effect of TRAIL with venetoclax in TP53INP2-positive acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is a hematopoietic malignancy with poor outcomes, especially in older AML patients. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is considered a promising anticancer drug because it selectively induces the extrinsic apoptosis of tumor cells without affecting normal cells. However, clinical trials have shown that the responses of patients to TRAIL are significantly heterogeneous. It is necessary to explore predictable biomarkers for the preselection of AML patients with better responsiveness to TRAIL. Here, we investigated the critical role of tumor protein p53 inducible nuclear protein 2 (TP53INP2) in the AML cell response to TRAIL treatment.

METHODS

First, the relationship between TP53INP2 and the sensitivity of AML cells to TRAIL was determined by bioinformatics analysis of Cancer Cell Line Encyclopedia datasets, Cell Counting Kit-8 assays, flow cytometry (FCM) and cell line-derived xenograft (CDX) mouse models. Second, the mechanisms by which TP53INP2 participates in the response to TRAIL were analyzed by Western blot, ubiquitination, coimmunoprecipitation and immunofluorescence assays. Finally, the effect of TRAIL alone or in combination with the BCL-2 inhibitor venetoclax (VEN) on cell survival was explored using colony formation and FCM assays, and the effect on leukemogenesis was further investigated in a patient-derived xenograft (PDX) mouse model.

RESULTS

AML cells with high TP53INP2 expression were more sensitive to TRAIL in vitro and in vivo. Gain- and loss-of-function studies demonstrated that TP53INP2 significantly enhanced TRAIL-induced apoptosis, especially in AML cells with nucleophosmin 1 (NPM1) mutations. Mechanistically, cytoplasmic TP53INP2 maintained by mutant NPM1 functions as a scaffold bridging the ubiquitin ligase TRAF6 to caspase-8 (CASP 8), thereby promoting the ubiquitination and activation of the CASP 8 pathway. More importantly, simultaneously stimulating extrinsic and intrinsic apoptosis signaling pathways with TRAIL and VEN showed strong synergistic antileukemic activity in AML cells with high levels of TP53INP2.

CONCLUSION

Our findings revealed that TP53INP2 is a predictor of responsiveness to TRAIL treatment and supported a potentially individualized therapeutic strategy for TP53INP2-positive AML patients.

Monocytic Differentiation in Acute Myeloid Leukemia Cells: Diagnostic Criteria, Biological Heterogeneity, Mitochondrial Metabolism, Resistance to and Induction by Targeted Therapies

We review the importance of monocytic differentiation and differentiation induction in non-APL (acute promyelocytic leukemia) variants of acute myeloid leukemia (AML), a malignancy characterized by proliferation of immature myeloid cells. Even though the cellular differentiation block is a fundamental characteristic, the AML cells can show limited signs of differentiation. According to the French-American-British (FAB-M4/M5 subset) and the World Health Organization (WHO) 2016 classifications, monocytic differentiation is characterized by morphological signs and the expression of specific molecular markers involved in cellular communication and adhesion. Furthermore, monocytic FAB-M4/M5 patients are heterogeneous with regards to cytogenetic and molecular genetic abnormalities, and monocytic differentiation does not have any major prognostic impact for these patients when receiving conventional intensive cytotoxic therapy. In contrast, FAB-M4/M5 patients have decreased susceptibility to the Bcl-2 inhibitor venetoclax, and this seems to be due to common molecular characteristics involving mitochondrial regulation of the cellular metabolism and survival, including decreased dependency on Bcl-2 compared to other AML patients. Thus, the susceptibility to Bcl-2 inhibition does not only depend on general resistance/susceptibility mechanisms known from conventional AML therapy but also specific mechanisms involving the molecular target itself or the molecular context of the target. AML cell differentiation status is also associated with susceptibility to other targeted therapies (e.g., CDK2/4/6 and bromodomain inhibition), and differentiation induction seems to be a part of the antileukemic effect for several targeted anti-AML therapies. Differentiation-associated molecular mechanisms may thus become important in the future implementation of targeted therapies in human AML.

Pharmacokinetics and immunogenicity of eftozanermin alfa in subjects with previously-treated solid tumors or hematologic malignancies: results from a phase 1 first-in-human study

PURPOSE

Eftozanermin alfa is a second-generation tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor agonist that enhances death receptor 4/5 clustering on tumor cells to induce apoptosis. We report the pharmacokinetics and immunogenicity of eftozanermin alfa administered intravenously to 153 adults with previously-treated solid tumors or hematologic malignancies from the first-in-human, open-label, dose-escalation and dose-optimization study.

METHODS

Dose escalation evaluated eftozanermin alfa monotherapy 2.5-15 mg/kg on Day 1 or Days 1/8 of a 21-day cycle. Dose optimization evaluated eftozanermin alfa monotherapy or combination therapy with either oral venetoclax 400-800 mg daily (eftozanermin alfa 1.25-7.5 mg/kg Days 1/8/15 of a 21-day cycle) or chemotherapy (eftozanermin alfa 3.75 or 7.5 mg/kg Days 1/8/15/22 of a 28-day cycle and FOLFIRI regimen [leucovorin, 5-fluorouracil, and irinotecan] with/without bevacizumab on Days 1/15 of a 28-day cycle).

RESULTS

Systemic exposures (maximum observed concentration [Cmax] and area under the concentration-time curve [AUC]) of eftozanermin alfa were approximately dose-proportional across the entire dose escalation range with minimal to no accumulation in Cycle 3 versus Cycle 1 exposures. Comparable exposures and harmonic mean half-lives (35.1 h [solid tumors], 31.3 h [hematologic malignancies]) were observed between malignancy types. Exposures (dose-normalized Cmax and AUC) in Japanese subjects were similar to non-Japanese subjects. Furthermore, eftozanermin alfa/venetoclax combination therapy did not have an impact on the exposures of either agent. Treatment-emergent anti-drug antibodies were observed in 9.4% (13/138) of subjects.

CONCLUSIONS

The study results, including a pharmacokinetic profile consistent with weekly dosing and low incidence of immunogenicity, support further investigation of eftozanermin alfa.

TRIAL REGISTRATION ID

NCT03082209.

PIEZO1 is essential for the survival and proliferation of acute myeloid leukemia cells

INTRODUCTION

Leukemogenesis is a complex process that interconnects tumoral cells with their microenvironment, but the effect of mechanosensing in acute myeloid leukemia (AML) blasts is poorly known. PIEZO1 perceives and transmits the constraints of the environment to human cells by acting as a non-selective calcium channel, but very little is known about its role in leukemogenesis.

RESULTS

For the first time, we show that PIEZO1 is preferentially expressed in healthy hematopoietic stem and progenitor cells in human hematopoiesis, and globally overexpressed in AML cells. In AML subtypes, PIEZO1 expression associates with favorable outcomes as better overall (OS) and disease-free survival (DFS). If PIEZO1 is expressed and functional in THP1 leukemic myeloid cell line, its chemical activation doesn't impact the proliferation, differentiation, nor survival of cells. However, the downregulation of PIEZO1 expression dramatically reduces the proliferation and the survival of THP1 cells. We show that PIEZO1 knock-down blocks the cell cycle in G0/G1 phases of AML cells, impairs the DNA damage response pathways, and critically increases cell death by triggering extrinsic apoptosis pathways.

CONCLUSIONS

Altogether, our results reveal a new role for PIEZO1 mechanosensing in the survival and proliferation of leukemic blasts, which could pave the way for new therapeutic strategies to target AML cells.

Expression of DR4, DR5, FAS, Caspase-8 and, DDIAS Genes in AML Patients

Background

Acute myeloid leukemia (AML) is the most common acute leukemia in adults and accompanies a worse survival. In this study, gene expression levels of 5 key players of apoptosis, including DR4, DR5, FAS, caspase 8, and DNA damage-induced apoptosis suppressor (DDIAS), have been evaluated in AML patients compared with controls, aiming to evaluate their possible role and prognostic impact.

Methods

This cross-sectional study was performed in the Cancer Molecular Pathology Research Center, Mashhad University of Medical Sciences. A total of 30 newly diagnosed AML cases as well as 30 healthy controls enrolled in the study. Real-time polymerase chain reaction was used to evaluate the expressions of DR4, DR5, FAS, DDIAS, and caspase 8 genes in cases and controls. Other necessary data, including cytogenetic findings, mutations, French-American-British (FAB) classification, and survival, were retrieved from hospital records and by direct contact with patients. Statistical analysis was done by SPSS software. When appropriate, the Mann-Whitney U, Pearson's correlation, and the t tests were utilized. Overall survival (OS) was estimated using the Kaplan-Meier method.

Results

The expression of all evaluated genes, including DDIAS (0.89 ± 0.20), DR4 (0.67 ± 0.24), DR5 (0.72 ± 0.24), FAS (0.70 ± 0.25), and Caspase 8 (0.77 ± 0.20) were significantly decreased in AML patients compared with the controls (P < 0.001). Patients with the t (16;16) or inv (16) expressed significantly higher amounts of the FAS gene and those with FLT3 mutation exhibited lower expression of caspase 8. Expression of the evaluated genes showed no significant effect on survival.

Conclusion

The expression of DR4, DR5, FAS, and caspase 8 seems to be decreased in AML. Lower expression of these molecules may aid AML cells in avoiding apoptosis because they are involved in the initiation of apoptosis, making them potential targets for treatment.