NOD/SCID IL2Rγ-null mouse xenograft model of human p53-mutated chronic lymphocytic leukemia and ATM-mutated mantle cell lymphoma using permanent cell lines

Targeting cancer homing into the lymph node with a novel anti-CCR7 therapeutic antibody: the paradigm of CLL

Lymph node (LN) is a key tissue in the pathophysiology of mature blood cancers, especially for chronic lymphocytic leukemia (CLL). Within the multiple de-regulated pathways affecting CLL homeostasis, the CC-chemokine receptor 7 (CCR7) grants homing of CLL cells into the LN where protective environments foster tumor progression. To cover the lack of specific therapies targeting the CCR7-dependence of CLL to enter into the LN, and aiming to displace the disease from LN, we generated CAP-100, an antibody that specifically binds to hCCR7 and neutralizes its ligand-binding site and signaling. In various in vitro and in vivo preclinical models CAP-100 strongly inhibited CCR7-induced migration, extravasation, homing, and survival in CLL samples. Moreover, it triggered potent tumor cell killing, mediated by host immune mechanisms, and was effective in xenograft models of high-risk disease. Additionally, CAP-100 showed a favorable toxicity profile on relevant hematopoietic subsets. Our results validated CAP-100 as a novel therapeutic tool to prevent the access of CLL cells, and other neoplasia with nodal-dependence, into the LN niches, thus hitting a central hub in the pathogenesis of cancer. The first-in-human clinical trial (NCT04704323), which will evaluate this novel therapeutic approach in CLL patients, is pending.

Anti-Tumour Activity of Glycodendrimer Nanoparticles in a Subcutaneous MEC-1 Xenograft Model of Human Chronic Lymphocytic Leukemia

BACKGROUND

Chronic Lymphocytic Leukaemia (CLL) is an indolent disorder, which mainly affects older adults. Since the advent of chemoimmunotherapy, great progress has been made in its treatment. However, some patients develop a more aggressive form of the disease and are included in the group of high-risk CLL patients with a dismal prognosis and a need for new therapies.

OBJECTIVE

Maltotriose-modified poly(propylene imine) dendrimers were presented as potential agents in targeted therapy for CLL in the murine xenograft model.

METHODS

Tumour, brain and internal organs resected from NOD scid gamma mice were subjected to gross and histopathological evaluation.

RESULTS

The results of ex vivo tissue examination indicated that open-shell glycodendrimers prevented/inhibited the spread of CLL into the brain and internal organs and its transformation into a more aggressive form.

CONCLUSION

The results of the study have a potentially important impact on the design of future personalized therapies as well as clinical trials.

Maltotriose-modified poly(propylene imine) Glycodendrimers as a potential novel platform in the treatment of chronic lymphocytic Leukemia. A proof-of-concept pilot study in the animal model of CLL

Cancer nanotherapeutics have shown promise in resolving some of the limitations of conventional drug delivery systems such as nonspecific biodistribution and targeting, lack of water solubility, and low therapeutic indices, Among the various nanoparticles that are available, dendrimers, highly branched macromolecules with a specific size and shape, are one of the most promising ones. In this preliminary study, we tested the anti-tumor activity of maltotriose-modified fourth-generation poly(propylene imine) glycodendrimers (PPI-G4-M3) in vivo in the subcutaneous MEC-1 xenograft model of human chronic lymphocytic leukemia (CLL) in NOD scid gamma mice. Fludarabine was used for model validation and as a positive treatment control. The anti-tumor response was calculated as tumor volume, tumor control ratio, and tumor growth inhibition. The study showed that PPI-G4-M3 inhibited subcutaneous tumor growth more efficiently than fludarabine. The anti-tumor response was dose-dependent. Cationic PPI-G4-M3 showed the highest anti-tumor activity but also higher toxicity than the neutral dendrimers and fludarabine. These first promising results warrant further studies in the optimization of dendrimers charge, dose, route and schedule of administration to combat CLL.

Novel CHK1 inhibitor MU380 exhibits significant single-agent activity in TP53-mutated chronic lymphocytic leukemia cells

Introduction of small-molecule inhibitors of B-cell receptor signaling and BCL2 protein significantly improves therapeutic options in chronic lymphocytic leukemia. However, some patients suffer from adverse effects mandating treatment discontinuation, and cases with TP53 defects more frequently experience early progression of the disease. Development of alternative therapeutic approaches is, therefore, of critical importance. Here we report details of the anti-chronic lymphocytic leukemia single-agent activity of MU380, our recently identified potent, selective, and metabolically robust inhibitor of checkpoint kinase 1. We also describe a newly developed enantioselective synthesis of MU380, which allows preparation of gram quantities of the substance. Checkpoint kinase 1 is a master regulator of replication operating primarily in intra-S and G₂/M cell cycle checkpoints. Initially tested in leukemia and lymphoma cell lines, MU380 significantly potentiated efficacy of gemcitabine, a clinically used inducer of replication stress. Moreover, MU380 manifested substantial single-agent activity in both TP53-wild type and TP53-mutated leukemia and lymphoma cell lines. In chronic lymphocytic leukemia-derived cell lines MEC-1, MEC-2 (both TP53-mut), and OSU-CLL (TP53-wt) the inhibitor impaired cell cycle progression and induced apoptosis. In primary clinical samples, MU380 used as a single-agent noticeably reduced the viability of unstimulated chronic lymphocytic leukemia cells as well as those induced to proliferate by anti-CD40/IL-4 stimuli. In both cases, effects were comparable in samples harboring p53 pathway dysfunction (TP53 mutations or ATM mutations) and TP53-wt/ATM-wt cells. Lastly, MU380 also exhibited significant in vivo activity in a xenotransplant mouse model (immunodeficient strain NOD-scid IL2Rγ^null) where it efficiently suppressed growth of subcutaneous tumors generated from MEC-1 cells.

Loss of thyroid hormone receptor interactor 13 inhibits cell proliferation and survival in human chronic lymphocytic leukemia

Background

The genetic regulation of apoptosis and cell proliferation plays a role in the growth of chronic lymphocytic leukemia (CLL), the most common form of leukemia in the Western hemisphere. Although thyroid hormone receptor interactors (TRIPs) are known to play roles in cell cycle, the potential involvement of the novel family member TRIP13 in CLL has not yet been investigated.

Methods

Quantitative PCR (qPCR) was used to detect expression of TRIP13 in 36 CLL patients and 33 healthy donors CD19+ B cells. Loss-of-function (siRNA) assays were used to alter TRIP13 expression levels. The effect of TRIP13 on cell proliferation and apoptosis was measured by MTT, Annexin V-based flow cytometry and Caspase 3/7 activity assay. Affymetrix GeneChip and Ingenuity Pathway Analysis (IPA) were used to describe an overview of TRIP13 potential biological function and downstream pathways. Dual-luciferase reporter assay was performed to assess the promoting effect of c-MYC on TRIP13 transcription.

RESULTS

The qPCR data showed that TRIP13 is significantly over-expressed in CLL patients. Microarray analyses indicated that the biological function of TRIP13 in CLL is majorly cell apoptosis and cell proliferation associated. TRIP13 siRNA expressing cells exhibited a slower cell proliferation rate and underwent apoptosis compared with control cells. TRIP13 knockdown induced CLL cells apoptosis through PUMA independent of p53. TRIP13 up-regulation is induced by c-MYC dependent transcriptional activation.

Conclusion

Overall, our data suggest the bio-function of TRIP13 in CLL cell for the first time, and that this gene might be a therapeutic target for CLL.

Murine Models of Splenic Marginal Zone Lymphoma: A Role for Cav1?

Dozens of murine models of indolent and aggressive B-cell lymphomas have been generated to date. These include those manifesting chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL), as well as xenografts of mantle cell lymphoma (MCL). These models have led to an improved understanding of disease etiology, B-cell biology, immunomodulation, and the importance of the tumor microenvironment. Despite these efforts in CLL, DLBCL, and MCL, considerably little progress toward a model of splenic marginal zone lymphoma (SMZL) has been accomplished. Herein, we describe the similarities and differences between CLL, MCL, and SMZL and highlight effective murine models that mimic disease in the two former, in hopes of informing a potential model of the latter. At the time of writing this review, the precise molecular events of SMZL remain to be determined and a treatment regimen remains to be identified. Therefore, based on the efforts put forth in the B-cell lymphoma field throughout the past three decades, the established role of caveolin-1 in B- and T-cell biology as an oncogene or tumor suppressor, and the recurrent deletion or loss of heterozygosity (LOH) of 7q in many cancers, we make recommendations for a murine model of SMZL.