In Vivo Assessment of the Next Generation Microtubule-Destabilizing Agent AB8939 in Patient-Derived Xenograft Models of Acute Myeloid Leukemia

AB8939 is a novel, synthesized, small-molecule microtubule-destabilizer drug with proven prolific and potent in vitro activity against numerous cancer cell lines. In vitro and ex vivo studies (reported separately) have determined that AB8939 is well-suited for the treatment of hematopoietic tumors, in particular relapsed/refractory or poor-prognosis acute myeloid leukemia (AML), notably being able to circumvent two major resistance mechanisms associated with AML (i.e. P-glycoprotein and myeloperoxidase-mediated resistance). The therapeutic potential of AB8939 was investigated further through a series of in vivo experiments using three patient derived xenograft (PDX) mouse models and a cytarabine (Ara-C) resistant mouse model (MOLM14). MOLM14 cells and selected PDX primary cells were transduced to constitutively express luciferase for bioluminescence monitoring of tumor growth. In an Ara-C-sensitive AML PDX mouse model (ex vivo IC50 response to Ara-C in survival/proliferation assays was 0.82 µM), AB8939 (6 mg/kg in weekly cycles of 5 consecutive days) showed a statistically significant, 10-fold decrease in the amount of blasts detected in blood following 14 days of treatment compared with control, and a superior treatment effect compared with Ara-C (single cycle of 10 mg/kg twice per day for 4 consecutive days) in terms of decreased blasts in blood. In an Ara-C-refractory AML PDX mouse model (ex vivo IC50 response to Ara-C in survival/proliferation assays was 6.4 µM), animals treated with single agent AB8939 (6 mg/kg in weekly cycles of 5 consecutive days) showed reduced disease progression compared with control and Ara-C (single cycle of 10 mg/kg twice per day for 4 consecutive days) as evidenced from at least 10-times fewer blasts in blood, spleen and bone marrow following 28 days of treatment. This effect was even more pronounced for the combination treatment of AB8939 and Ara-C, suggesting a synergistic response. In a PDX mouse model that is highly resistant to Ara-C (ex vivo IC50 response to Ara-C in survival/proliferation assays was 8.3 µM), AB8939 as a single agent or in combination with Ara-C showed a significant (P <0.001) decrease in tumor growth and reduction of blasts in blood with respect to Ara-C and control, following 27 days of treatment (8 animals per group). This improvement translated to survival benefit, with the single agent AB8939 cohort having a median survival of 89 days compared with 69 days and 65.5 days in the control and Ara-C cohorts, respectively. Indeed, all animals treated with single agent AB8939 were still alive at D83 post injection, which was 30 days after treatment was stopped. AB8939 as a single agent was well-tolerated with no toxicity-related deaths or impact on body weight. A greater treatment effect was again observed for the AB8939 plus Ara-C combination; however, clear signs of higher toxicity mean it will be imperative to optimize dosage of both AB8939 and Ara-C if used in combination. For the well-established xenografted MOLM14 mouse model, immune-deficient NSG (NOD scid gamma) mice (5 animals per group) were injected intravenously with MOLM14-luciferase cells and treated over a period of 21 days with single agent AB8939 (subcutaneous injection) at a dosage of 6 mg/kg every day or 12 mg/kg every other day; Ara-C (intraperitoneal injection, single cycle of 10 mg/kg twice per day for 4 consecutive days); or vehicle. AB8939 caused a significant dose-dependent reduction in tumor volume (p=0.001) and increased survival with respect to control or single agent Ara-C (median survival at 6 and 12 mg/kg was 39 and 42 days, respectively, corresponding to a 60% improvement compared with the control and Ara-C groups). A similar dosing schedule study showed single agent AB8939 at 6 mg/kg administered over 6 consecutive days (6 ON/1 OFF) was optimal with this cohort having a median survival of 59 days, corresponding to a 100% improvement over control. Overall, these in vivo data provide compelling proof-of-concept for AB8939 as a treatment of AML. AB8939 administered alone or in combination with Ara-C was demonstrated to significantly increase survival and reduce tumor growth as compared with single agent Ara-C in relevant animal models of AML. A first in human, phase 1 trial evaluating AB8939 in AML patients unfit to receive intensive chemotherapy in second and third-line has been initiated. Disclosures Goubard: AB Science: Employment. Humbert:AB Science: Employment. Mansfield:AB Science: Employment, Patents & Royalties. Hermine:AB Science: Membership on an entity's Board of Directors or advisory committees. Dubreuil:AB Science: Employment, Membership on an entity's Board of Directors or advisory committees, Research Funding. AB8939 Study Group:AB Science: Consultancy, Employment.

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Inhibition Of Wee1 Enhances The Anti-Leukemic Effects Of Antimetabolites In Vitro and In Vivo

Blood ◽

10.1182/blood.v122.21.1281.1281 ◽

2013 ◽

Vol 122 (21) ◽

pp. 1281-1281

Author(s):

James B. Ford ◽

Susan Fosmire ◽

Annemie van Linden ◽

Dmitry Baturin ◽

Christopher C. Porter

Keyword(s):

Combination Therapy ◽

Mouse Model ◽

Acute Leukemia ◽

Cell Lines ◽

Conflicts Of Interest ◽

Ex Vivo ◽

Single Agent ◽

Parp Cleavage

Abstract While some patients with acute leukemia are cured, for many subsets of patients current therapeutic strategies are not adequate. Novel therapeutic approaches are needed for patients with higher risk leukemias, including T-ALL and AML. We and others identified Wee1 as a potential target in AML cells using RNAi screening. We have validated chemosensitization to cytarabine by genetic and pharmacologic inhibition of Wee1 in AML cell lines and primary patient samples ex vivo. A Wee1 inhibitor, MK1775, is in clinical development. We sought to further our findings with a wider range of conventional anti-leukemia agents, to determine whether the functionality of p53 influences chemosensitization, and to determine the tolerability and efficacy of MK1775 in combination with cytarabine in a mouse model of leukemia. We have found that MK1775 synergistically inhibits proliferation of the T-ALL Jurkat cell line with several antimetabolite chemotherapeutics including cytarabine, 6-thioguanine, and methotrexate. In contrast, MK1775 does not sensitize Jurkats to doxorubicin or etoposide, suggesting specific sensitization to antimetabolites. The addition of MK1775 enhances the antimetabolite induced apoptosis, as measured by Annexin V/7-AAD staining, and PARP cleavage measured by Western blotting. As expected, the addition of MK1775 enhances DNA damage induced by cytarabine as measured by γH2AX staining and flow cytometry, although preliminary data suggest that this is not the only mechanism of enhanced cell death, as a substantial proportion of cleaved PARP+ cells does not stain for γH2AX. In addition, we have found that AML cell lines with both wild-type and mutated TP53 are sensitive to chemosensitization by Wee1 inhibition. Furthermore, in isogenic models of p53 dysfunction, we have found that the functionality of p53 does not influence chemosensitization. Lastly, in an aggressive mouse model of AML, we observed enhanced disease control and survival in mice treated with MK1775 and ARA-C as compared to ARA-C alone. Hematotoxicity associated with treatment was related to the duration of combination therapy, but was tolerated well with intermittent dosing. Taken together, these data indicate that Wee1 inhibition may enhance the efficacy of several clinically relevant anti-leukemia agents, particularly the antimetabolites, but not topoisomerase inhibitors. Further, they suggest caution about the use of p53 mutation as a biomarker predictive of response to Wee1 inhibition. Moreover, we show that the addition of MK1775 to cytarabine is tolerable and more effective than cytarabine alone in vivo. Ongoing studies are aimed at better understanding the mechanism of combinatorial effect and to determine whether combination therapy is more efficacious than single agent therapy in xenograft models of leukemia. These data provide justification for early phase clinical trials of MK1775 in combination with antimetabolites in patients with high risk acute leukemia. Disclosures: No relevant conflicts of interest to declare.

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The Vk*MYC Mouse Model of Myeloma Identifies Successful Combination Therapies for the Treatment of Bortezomib Refractory Myeloma Patients

Blood ◽

10.1182/blood.v116.21.3015.3015 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3015-3015 ◽

Cited By ~ 1

Author(s):

Marta Chesi ◽

Stephen Palmer ◽

Victoria Garbitt ◽

P. Leif Bergsagel

Keyword(s):

Clinical Trials ◽

Mouse Model ◽

Board Of Directors ◽

Cell Lines ◽

Human Disease ◽

Single Agent ◽

Hdac Inhibitors ◽

Advisory Committees

Abstract Abstract 3015 Several preclinical models are available to assess the efficacy of novel anti-myeloma therapies, each of them with specific utilities. The most commonly utilized are: 1) Human myeloma cell lines (HMCLs) offer the advantage of being easily manipulated and well genetically characterized and therefore are best used to provide in-vitro target validation and to demonstrate specific target inhibition by a drug. On the other hand, they are highly proliferative and do not recapitulate the complexity of the human disease in an endogenous micro-environment. 2) Xenograft studies, in which HMCLs are injected into immunodeficient mice, serve the purpose of demonstrating that in-vivo target inhibition can be achieved under physiological conditions, but again fail to represent the indolence of human MM and its complex interaction with the BM stromal cells. Drug screenings performed on both these models tend inevitably to overestimate the antimyeloma activity of compounds that simply inhibit proliferation, but are ineffective in targeting the bulk of MM tumor. 3) Direct cytotoxic studies on primary patients cells, alone or in co-culture with stroma cell lines, are useful in assessing a pro-apoptotic activity in a way that is completely independent on proliferation. However, once again this in-vitro model does not capture the complete biology of human MM. The immuno-competent Vk*MYC mouse model of myeloma has already demonstrated high biological fidelity to the human disease, making it an ideal model to study the behavior of myeloma cells in the context of a native microenvironment and immune system. Furthermore, this model offers the advantage of studying both indolent, BM localized, untreated MM (primary MM), and, with the use of transplants into syngeneic hosts, advanced, more proliferative and refractory disease (secondary MM). Using the primary MM model, we have assessed the anti-myeloma activity of 30 known and novel compounds, many of which currently in clinical trials, and found that agents effective in the treatment of patients are active in this model, whereas agents ineffective in the treatment of patients are not. From this study, the most promising class of novel agents in clinical trials are the HDAC inhibitors vorinostat and panobinostat. Based on this promising single agent activity, we sought to model the effects of combination therapy in the secondary myeloma models that we specifically generated to be bortezomib refractory or multidrug resistance. Although transplanted mice treated with full dose single agent bortezomib, vorinostat or panobinostat showed no response and died within three weeks post transplant, recipient mice treated with bortezomib in combination with either vorinostat or panobinostat achieved complete response and are still alive 10 weeks post-transplant. We conclude that the bortezomib + HDAC inhibitors is an active combination that overcomes in vivo bortezomib resistance. Furthermore, the Vk*MYC model provides an excellent platform for the development of novel combinations aimed to the treatment of refractory MM disease. Disclosures: Bergsagel: Amgen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees; Millennium: Speakers Bureau; Novartis: Speakers Bureau.

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IMMU-31. QUANTITATIVE EVALUATION OF ROUTES OF ADMINISTRATION OF IMMUNOTHERAPEUTIC T CELLS TO ORTHOTOPIC GLIOMA

Neuro-Oncology ◽

10.1093/neuonc/noaa215.461 ◽

2020 ◽

Vol 22 (Supplement_2) ◽

pp. ii111-ii111

Author(s):

Lan Hoang-Minh ◽

Angelie Rivera-Rodriguez ◽

Fernanda Pohl-Guimarães ◽

Seth Currlin ◽

Christina Von Roemeling ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Tumor Growth ◽

Ex Vivo ◽

Adoptive T Cell Therapy ◽

Whole Body ◽

T Cell Therapy ◽

Clinical Responses

Abstract SIGNIFICANCE Adoptive T cell therapy (ACT) has emerged as the most effective treatment against advanced malignant melanoma, eliciting remarkable objective clinical responses in up to 75% of patients with refractory metastatic disease, including within the central nervous system. Immunologic surrogate endpoints correlating with treatment outcome have been identified in these patients, with clinical responses being dependent on the migration of transferred T cells to sites of tumor growth. OBJECTIVE We investigated the biodistribution of intravenously or intraventricularly administered T cells in a murine model of glioblastoma at whole body, organ, and cellular levels. METHODS gp100-specific T cells were isolated from the spleens of pmel DsRed transgenic C57BL/6 mice and injected intravenously or intraventricularly, after in vitro expansion and activation, in murine KR158B-Luc-gp100 glioma-bearing mice. To determine transferred T cell spatial distribution, the brain, lymph nodes, heart, lungs, spleen, liver, and kidneys of mice were processed for 3D imaging using light-sheet and multiphoton imaging. ACT T cell quantification in various organs was performed ex vivo using flow cytometry, 2D optical imaging (IVIS), and magnetic particle imaging (MPI) after ferucarbotran nanoparticle transfection of T cells. T cell biodistribution was also assessed in vivo using MPI. RESULTS Following T cell intravenous injection, the spleen, liver, and lungs accounted for more than 90% of transferred T cells; the proportion of DsRed T cells in the brains was found to be very low, hovering below 1%. In contrast, most ACT T cells persisted in the tumor-bearing brains following intraventricular injections. ACT T cells mostly concentrated at the periphery of tumor masses and in proximity to blood vessels. CONCLUSIONS The success of ACT immunotherapy for brain tumors requires optimization of delivery route, dosing regimen, and enhancement of tumor-specific lymphocyte trafficking and effector functions to achieve maximal penetration and persistence at sites of invasive tumor growth.

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Promising potential of [177Lu]Lu-DOTA-folate to enhance tumor response to immunotherapy—a preclinical study using a syngeneic breast cancer model

European Journal of Nuclear Medicine and Molecular Imaging ◽

10.1007/s00259-020-05054-9 ◽

2020 ◽

Author(s):

Patrycja Guzik ◽

Klaudia Siwowska ◽

Hsin-Yu Fang ◽

Susan Cohrs ◽

Peter Bernhardt ◽

...

Keyword(s):

Tumor Growth ◽

Survival Time ◽

Tumor Cells ◽

Median Survival ◽

Breast Tumor ◽

Median Survival Time ◽

Therapy Outcome ◽

Minor Effect

Abstract Purpose It was previously demonstrated that radiation effects can enhance the therapy outcome of immune checkpoint inhibitors. In this study, a syngeneic breast tumor mouse model was used to investigate the effect of [177Lu]Lu-DOTA-folate as an immune stimulus to enhance anti-CTLA-4 immunotherapy. Methods In vitro and in vivo studies were performed to characterize NF9006 breast tumor cells with regard to folate receptor (FR) expression and the possibility of tumor targeting using [177Lu]Lu-DOTA-folate. A preclinical therapy study was performed over 70 days with NF9006 tumor-bearing mice that received vehicle only (group A); [177Lu]Lu-DOTA-folate (5 MBq; 3.5 Gy absorbed tumor dose; group B); anti-CTLA-4 antibody (3 × 200 μg; group C), or both agents (group D). The mice were monitored regarding tumor growth over time and signs indicating adverse events of the treatment. Results [177Lu]Lu-DOTA-folate bound specifically to NF9006 tumor cells and tissue in vitro and accumulated in NF9006 tumors in vivo. The treatment with [177Lu]Lu-DOTA-folate or an anti-CTLA-4 antibody had only a minor effect on NF9006 tumor growth and did not substantially increase the median survival time of mice (23 day and 19 days, respectively) as compared with untreated controls (12 days). [177Lu]Lu-DOTA-folate sensitized, however, the tumors to anti-CTLA-4 immunotherapy, which became obvious by reduced tumor growth and, hence, a significantly improved median survival time of mice (> 70 days). No obvious signs of adverse effects were observed in treated mice as compared with untreated controls. Conclusion Application of [177Lu]Lu-DOTA-folate had a positive effect on the therapy outcome of anti-CTLA-4 immunotherapy. The results of this study may open new perspectives for future clinical translation of folate radioconjugates.

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Combining Immunocytokine and Ex Vivo Activated NK Cells as a Platform for Enhancing Graft-Versus-Tumor Effects Against GD2+ Murine Neuroblastoma

Frontiers in Immunology ◽

10.3389/fimmu.2021.668307 ◽

2021 ◽

Vol 12 ◽

Author(s):

Paul D. Bates ◽

Alexander L. Rakhmilevich ◽

Monica M. Cho ◽

Myriam N. Bouchlaka ◽

Seema L. Rao ◽

...

Keyword(s):

Tumor Growth ◽

Nk Cells ◽

Nk Cell ◽

Ex Vivo ◽

Cell Transplant ◽

Hematopoietic Stem ◽

Allogeneic Hsct ◽

Tnf Α

Management for high-risk neuroblastoma (NBL) has included autologous hematopoietic stem cell transplant (HSCT) and anti-GD2 immunotherapy, but survival remains around 50%. The aim of this study was to determine if allogeneic HSCT could serve as a platform for inducing a graft-versus-tumor (GVT) effect against NBL with combination immunocytokine and NK cells in a murine model. Lethally irradiated C57BL/6 (B6) x A/J recipients were transplanted with B6 bone marrow on Day +0. On day +10, allogeneic HSCT recipients were challenged with NXS2, a GD2+ NBL. On days +14-16, mice were treated with the anti-GD2 immunocytokine hu14.18-IL2. In select groups, hu14.18-IL2 was combined with infusions of B6 NK cells activated with IL-15/IL-15Rα and CD137L ex vivo. Allogeneic HSCT alone was insufficient to control NXS2 tumor growth, but the addition of hu14.18-IL2 controlled tumor growth and improved survival. Adoptive transfer of ex vivo CD137L/IL-15/IL-15Rα activated NK cells with or without hu14.18-IL2 exacerbated lethality. CD137L/IL-15/IL-15Rα activated NK cells showed enhanced cytotoxicity and produced high levels of TNF-α in vitro, but induced cytokine release syndrome (CRS) in vivo. Infusing Perforin-/- CD137L/IL-15/IL-15Rα activated NK cells had no impact on GVT, whereas TNF-α-/- CD137L/IL-15/IL-15Rα activated NK cells improved GVT by decreasing peripheral effector cell subsets while preserving tumor-infiltrating lymphocytes. Depletion of Ly49H+ NK cells also improved GVT. Using allogeneic HSCT for NBL is a viable platform for immunocytokines and ex vivo activated NK cell infusions, but must be balanced with induction of CRS. Regulation of TNFα or activating NK subsets may be needed to improve GVT effects.

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Abstract 23: Microrna302-367 Sphingosine 1 Phosphate Receptor 1 Pathway Prevents Tumor Growth via Restricting Angiogenesis and Enhancing Vascular Stability

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.36.suppl_1.23 ◽

2016 ◽

Vol 36 (suppl_1) ◽

Author(s):

Jinjiang Pi ◽

Ting Tao ◽

Tao Zhuang ◽

Huimin Sun ◽

Xiaoli Chen ◽

...

Keyword(s):

Endothelial Cells ◽

Tumor Growth ◽

Ex Vivo ◽

Downstream Target ◽

Sprouting Angiogenesis ◽

Pathological Angiogenesis ◽

Vascular Stability ◽

Sphingosine 1 Phosphate

Angiogenic hypersprouting and leaky immature vessels of pathological angiogenesis are essential for tumor growth. MicroRNAs have unique therapeutic advantages by targeting multiple pathways of tumor-associated angiogenesis, but the function of individual miRNAs in angiogenesis and tumors has not yet been fully evaluated. Here, we show that miR302-367 elevation in endothelial cells reduces retina sprouting angiogenesis and promotes vascular stability in vivo, ex vivo and in vitro. Erk1/2 are identified as direct targets of miR302-367, and down-regulation of Erk1/2 upon miR302-367 elevation in endothelial cells increases the expression of Klf2 and in turn S1pr1 and its downstream target VE-cadherin, suppressing angiogenesis and improving vascular stability. Conversely, both pharmacological blockade and genetic deletion of S1pr1 in endothelial cells reverse the anti-angiogenic and vascular stabilizing effect of miR302-367 in mice. Pathological angiogenesis in tumors shares features of developmental angiogenesis, and endothelial specific elevation of miR302-367 reduces tumor growth by restricting sprout angiogenesis and decreasing vascular permeability via the same Erk1/2-Klf2-S1pr1 pathways. In conclusion, miR302-367 regulation of an Erk1/2-Klf2-S1pr1 pathway in the endothelium advances our understanding of angiogenesis, meanwhile also provides opportunities for therapeutic intervention of tumor growth.

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HCD122, an Antagonist Human Anti-CD40 Monoclonal Antibody, Enhances Efficacy of CHOP in Tumor Xenograft Model of Human Diffuse Large B-Cell Lymphoma.

Blood ◽

10.1182/blood.v110.11.528.528 ◽

2007 ◽

Vol 110 (11) ◽

pp. 528-528 ◽

Cited By ~ 1

Author(s):

Mohammad Luqman ◽

Ssucheng J. Hsu ◽

Matthew Ericson ◽

Sha Klabunde ◽

Seema Kantak

Keyword(s):

Monoclonal Antibody ◽

Clinical Trials ◽

Tumor Growth ◽

Cell Lymphoma ◽

Single Agent ◽

B Cell Lymphoma ◽

Large B Cell Lymphoma ◽

Large B Cell

Abstract HCD122 (formerly known as CHIR-12.12), is a fully human anti-CD40 monoclonal antibody (mAb) currently in Phase I clinical trials for treatment of chronic lymphocytic leukemia (CLL) and multiple myeloma (MM). An IgG1 antibody selected for its potency as an antagonist of the CD40 signaling pathway, HCD122 both inhibits CD40/CD40L-stimulated growth of lymphoma cells ex vivo, and mediates highly effective Antibody Dependent Cell-mediated Cytotoxicity (ADCC) in vitro. As a single agent, HCD122 exhibits potent anti-tumor activity in vivo, in preclinical models of MM, Hodgkin’s lymphoma, Burkitt’s lymphoma, mantle cell lymphoma and diffused large B-cell lymphoma (DLBCL). Although several therapeutic antibodies approved for treatment of Non-Hodgkin’s Lymphoma have clinical activity as single agents, combining these antibodies with standard-of-care chemotherapeutic regimens such as CHOP (cytoxan, vincristine, doxorubicin and prednisone) is proving optimal for both increasing response rates and extending survival, and antibodies currently in clinical development are likely to be used in combination therapies in the future. Therefore the studies reported here examine the effects of combining HCD122 with CHOP, the standard for treatment of high grade NHL, in in vitro and in vivo models of DLBCL. In the xenograft RL model of DLBCL, HCD122 administered intraperitoneally weekly at 1 mg/kg as a single agent, or in combination with CHOP (H-CHOP), and CHOP alone all significantly reduced tumor growth at day 25 when compared to treatment with huIgG1 control antibody (P<0.001). However, tumor growth delay (time to reach tumor size of 500 mm3) was significantly longer for H-CHOP (17.5 days), than for CHOP (8 days) or HCD122 (6 days) (p < 0.001). No toxicity was observed with the H-CHOP combination. Interestingly, at the end of the study (day 35), reduction in tumor growth was significantly greater in the treatment group that received H-CHOP than the groups that received either 10 mg/kg Rituxan plus CHOP (R-CHOP) (p < 0.05) or CHOP alone (p < 0.001). These data show that in this model, treatment with the combination H-CHOP results in greater anti-tumor efficacy than with either modality alone or R-CHOP. We have observed that in vitro, exposure to CD40 Ligand (CD40L) results in aggregation of DLBCL cells, and postulate that interfering with the ability of cancer cells to adhere and interact with each other and their microenvironment may potentiate the effect of chemotherapeutics. To elucidate the mechanism by which the combination of HCD122 and CHOP enhanced efficacy in vivo, we developed an in vitro system to examine the effects of HCD122 on the expression of adhesion molecules in the RL and SU-DHL-4 cell lines. In these studies, HCD122 inhibited CD40L-induced expression of CD54, CD86 and CD95 in both cell lines, as well as aggregation of SU-DHL-4 cells. The combined effect of each of the components of CHOP with HCD122 in three-dimensional spheroid cultures is currently under investigation. These data provide a therapeutic rationale for combination of HCD122 with CHOP in DLBCL clinical trials.

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Evaluation of IGHV Ultra-Deep Sequences for Activation-Induced Deaminase Characteristics in CLL Cells after T Cell Stimulation

Blood ◽

10.1182/blood.v122.21.2583.2583 ◽

2013 ◽

Vol 122 (21) ◽

pp. 2583-2583

Author(s):

Charles C. Chu ◽

Piers E.M. Patten ◽

Thomas MacCarthy ◽

Xiao-Jie Yan ◽

Jacqueline C. Barrientos ◽

...

Keyword(s):

T Cell ◽

Board Of Directors ◽

Deep Sequencing ◽

Ex Vivo ◽

Advisory Committees ◽

Polymerase Eta ◽

Activation Induced Deaminase ◽

T Cell Help

Abstract Ultra-deep sequencing has revolutionized our ability to acquire large amounts of genetic data. We have applied this technology towards understanding the mutational process in B-cell chronic lymphocytic leukemia (CLL), which may be a key to understanding CLL pathogenesis. Acquisition of new cytogenetic aberrations and gene mutations in the CLL clone is associated with worse patient outcome. CLL is not unique in this aspect, as new somatic mutations and DNA rearrangements are also found during the evolution of other solid and liquid tumors. In many of these, activation-induced deaminase (AID), an enzyme normally expressed in germinal center B lymphocytes to induce IGHV-D-J mutations and isotype class switch recombination, is abnormally expressed. Its mutational activity, acting outside of the Ig loci, is implicated in the evolution to more aggressive disease. In CLL, the detection of leukemic cells expressing AID ex vivo correlates with significantly shorter patient survival. To test if AID mutational activity is functional in CLL cells and therefore could contribute to CLL evolution, we analyzed mutations in IGHV-D-J, the preferred substrate for AID. Because the rate of AID-induced mutation is low and only a small percentage of CLL cells express AID ex vivo, we used ultra-deep sequencing to analyze CLL cells that were activated under conditions that simulate the CLL microenvironment. Specifically, CLL cells were activated (1) in vitro by simulating the provision of T-cell help or (2) in vivo after adoptive transfer into alymphoid recipient mice, which requires the presence of T-cells for CLL cell growth. Each of these conditions induce AID in a large fraction of CLL cells. To analyze IGHV-D-J mutations, the specific CLL clone IGHV was amplified from cDNA obtained on day 0 or from the activated CLL samples using IGHV family-specific and IGHM primers to enable subsequent comparison of IGHV-D-J with IGHM mutation frequencies. Three unmutated IGHV CLL (U-CLL) and 3 mutated IGHV (>2% compared to germline) CLL (M-CLL) samples were sequenced with the Roche 454 FLX system, resulting in a total of 1,367,522 sequence reads. After using the Roche 454 algorithm to trim sequence reads, they were prepared using custom R scripts that separated 5’ IGHV and 5’ IGHM primer sequences, aligned sequences to the CLL clone IGHV-D-J rearrangement, and removed poor quality (<20) sequences, insertions, and deletions. Beginning at the 5’ end, the script also extracted blocks of sequences of the same length for day 0 and activated samples, which are required for subsequent analyses. After these preparations, the resulting 724,855 sequence blocks were subjected to clonal analyses with custom R scripts. The dominant CLL clone accounted for 94.5% (684,691) of the sequences. Subclone sequences occurring more than once were extracted. After comparison to day 0, new subclones could be identified in all samples after activation (3.22 – 28.70 new subclones / read bp *106). To evaluate AID mutational characteristics in new subclones, SHMTool (http://scb.aecom.yu.edu/shmtool) was employed to calculate mutation frequencies in IGHV-D-J relative to the IGHM constant region, at AID mutation hotspot sites (GYW or WRC), at AID mutation coldspot sites (SYC or GRS), at C/G base pairs, and at error-prone DNA polymerase eta repair hotspot sites (WA or TW). To calculate statistical significance, we utilized a custom R script that used a bootstrap method to account for the large sample sizes provided by ultra-deep sequencing as well as to correct for differences in sequencing sample size. All samples showed an increase in IGHV-D-J versus IGHM mutations after T cell activation. Five of 6 cases showed an increase in AID hostpot mutation frequency. AID coldspot mutation frequency decreased in 3/6 CLL cases. Percent transition mutation at C/G sites was higher than random in 2/6 CLL cases, which correlated with low frequencies of DNA polymerase eta hotspot mutation. In the other 4/6 CLL cases, the lower percent transitions at C/G sites may reflect the contribution of error-prone DNA repair. In summary, we developed a method to analyze ultra-deep IGHV-D-J sequences that revealed AID mutational characteristics in both U-CLL and M-CLL cells after activation with T-cell help in vitro or in vivo. These data are consistent with the hypothesis that AID, perhaps along with error-prone DNA repair, creates new mutations leading to the evolution of aggressive CLL. Disclosures: Rai: Sanofi: Membership on an entity’s Board of Directors or advisory committees; GSK: Membership on an entity’s Board of Directors or advisory committees; Teva: Membership on an entity’s Board of Directors or advisory committees; Genentech: Membership on an entity’s Board of Directors or advisory committees; Celgene: Membership on an entity’s Board of Directors or advisory committees.

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Nanoparticle Design For Bone-Specific Chemotherapy and Microenvironmental Targeting In Multiple Myeloma

Blood ◽

10.1182/blood.v122.21.881.881 ◽

2013 ◽

Vol 122 (21) ◽

pp. 881-881 ◽

Cited By ~ 1

Author(s):

Michaela R Reagan ◽

Archana Swami ◽

Pamela A Basto ◽

Yuji Mishima ◽

Jinhe Liu ◽

...

Keyword(s):

Bone Formation ◽

Tumor Growth ◽

Board Of Directors ◽

Bone Cells ◽

Release Kinetics ◽

In Vivo Model ◽

Advisory Committees ◽

Pre Treatment

Abstract Introduction The bone marrow (BM) niche is known to exert a protective effect on lymphoid tumors, such as multiple myeloma (MM), where mesenchymal stem cell interactions with clonal plasma cells increase tumor proliferation and survival. However, certain cells within the BM milieu, such as mature osteoblasts and osteocytes, have demonstrated the potential to inhibit tumor growth; utilizing these cells presents a promising new anti-cancer approach. Hence, designing better methods of bone-specific delivery for both direct cancer cell treatment and indirect treatment through the modulation of bone cells may result in a potent, two-pronged anti-cancer strategy. Our work aimed to develop a novel system to target both MM and bone cells to induce greater osteogenesis and hamper tumor growth. Methods PEG–PLGA nanoparticles (NPs) coupled to alendronate (“bone-targeted”) or alone (“non-targeted”) were formulated and loaded with bortezomib (“BTZ-NPs”) or left empty (“BTZ-free”). NPs were characterized for their physiochemical properties, including size (using dynamic light scattering; surface charges (Zeta potential); and bone affinity (using hydroxyapatite binding). NPs were engineered with different formulation methods and those with the optimal physiochemical characteristics and drug encapsulation efficiency were used for further studies. BTZ release kinetics were analyzed using HPLC. Anti-MM effects were assessed in vitro using MTT, bioluminescence (BLI) and Annexin V/PI apoptosis flow cytometry analysis on MM1S cells. In vivo, efficacy was measured by mouse weight, BLI and survival after i.v. cancer cell injections in mice. Cellular uptake was assessed in vitro by flow cytometry and in vivo biodistribution was assessed using fluorescent whole body and fixed section imaging. Bone specificity was assessed in vitro by co-culture of bone-targeted and non-targeted NPs with bone chips or hydroxyapatite using fluorescence and TEM imaging. In an in vivo model of myeloma treatment, female Nod/SCID beige mice were injected i.v. with 4 × 106 Luc+/GFP+ MM1S cells and, at day 21, treated with a) BTZ, b) BTZ-bone-targeted NPs, c) BTZ-non-targeted NPs or d) BTZ-free bone-targeted NPs. Using an in vivo model of pre-treatment for cancer prevention, mice were pre-treated with i.p. injections of BTZ-bone-targeted NPs and appropriate controls thrice weekly for 3 weeks. They were then injected i.v. with Luc+/GFP+ 5TGM1 or MM1S cells and monitored for BLI and survival. Static and dynamic bone histomorphometry and μCT were used to assess effects of pre-treatment on bone formation and osteolysis prevention. Results Our biodegradable, NPs had uniform size distribution within the range of 100 to 200 nm based on the type of formulation, with a zeta potential of ±5mV. Bone- targeted NPs showed high affinity towards bone mineral in vitro and better skeletal accumulation in vivo compared to non-targeted NPs. NPs were easily up-taken by cells in vitro, and BTZ release kinetics showed a burst followed by a sustained-release pattern over 60 hrs. BTZ-NPs induced apoptosis in MM cells in vitro. Importantly, BTZ-bone-targeted-NP pre-treated mice showed significantly less tumor burden (BLI) and longer survival than free drug or drug-free bone-targeted NPs, thus demonstrating a tumor-inhibiting effect unique to the BTZ-bone-targeted-NPs. Pre-treatment with BTZ increased bone formation in tibias and femurs, as measured by μCT of bone volume/total volume, and trabecular thickness and number, suggesting that increased bone volume may inhibit MM. In a second mouse model, both BTZ-bone-targeted NPs and BTZ-free NPs were equally able to reduce tumor growth in vivo when given after tumor formation. Conclusion Bone-targeted nanoparticles hold great potential for clinical applications in delivering chemotherapies to bone marrow niches, reducing off-target effects, increasing local drug concentrations, and lengthening the therapeutic window. BTZ-bone-targeted NPs are able to slow tumor growth and increase survival in mice when used as a pre-treatment. This may result, at least in part, from BTZ-induced increased bone formation. These findings indicate that BTZ-bone-targeted NPs exert a chemopreventive effect in MM in vivo, thus suggesting their potential use in the clinical setting. Disclosures: Basto: BIND Therapeutics: Patent licensed by BIND, Patent licensed by BIND Patents & Royalties. Farokhzad:BIND Therapeutics: Employment, Equity Ownership; Selecta Biosciences: Employment, Equity Ownership. Ghobrial:Onyx: Membership on an entity’s Board of Directors or advisory committees; BMS: Membership on an entity’s Board of Directors or advisory committees; BMS: Research Funding; Sanofi: Research Funding; Novartis: Membership on an entity’s Board of Directors or advisory committees.

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Development of A Novel Highly Selective TLR8 Agonist for Cancer Immunotherapy

10.1101/2020.03.14.991760 ◽

2020 ◽

Author(s):

Yuxun Wang ◽

Heping Yang ◽

Huanping Li ◽

Shuda Zhao ◽

Yikun Zeng ◽

...

Keyword(s):

Immune Responses ◽

Drug Targets ◽

Ex Vivo ◽

Single Agent ◽

Cancer Drug ◽

Phase I Clinical Trials ◽

Tlr Agonists ◽

Favorable Safety

ABSTRACTToll-like receptors (TLRs) are a family of proteins that recognize pathogen associated molecular patterns (PAMPs). Their primary function is to activate innate immune responses while also involved in facilitating adaptive immune responses. Different TLRs exert distinct functions by activating varied immune cascades. Several TLRs are being pursued as cancer drug targets. We discovered a novel, highly potent and selective small molecule TLR8 agonist DN052. DN052 exhibited strong in vitro cellular activity with EC50 at 6.7 nM and was highly selective for TLR8 over other TLRs including TLR4, 7 and 9. The selectivity profile distinguished DN052 from all other TLR agonists currently in clinical development. DN052 displayed excellent in vitro ADMET and in vivo PK profiles. DN052 potently inhibited tumor growth as a single agent. Moreover, combination of DN052 with the immune checkpoint inhibitor, selected targeted therapeutics or chemotherapeutic drugs further enhanced efficacy of single agents. Mechanistically, treatment with DN052 resulted in strong induction of pro-inflammatory cytokines in ex vivo human PBMC assay and in vivo monkey study. GLP toxicity studies in rats and monkeys demonstrated favorable safety profile. This led to the advancement of DN052 into phase I clinical trials.

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