AKT inhibition generates potent polyfunctional clinical grade AUTO1 CAR T-cells, enhancing function and survival.

BACKGROUND: AUTO1 is a fast off-rate CD19-targeting chimeric antigen receptor (CAR), which has been successfully tested in adult lymphoblastic leukemia. Tscm/Tcm-enriched CAR-T populations confer the best expansion and persistence, but Tscm/Tcm numbers are poor in heavily pretreated adult patients. To improve this, we evaluate the use of AKT inhibitor (VIII) with the aim of uncoupling T-cell expansion from differentiation, to enrich Tscm/Tcm subsets. METHODS: VIII was incorporated into the AUTO1 manufacturing process based on the semiautomated the CliniMACS Prodigy platform at both small and cGMP scale. RESULTS: AUTO1 manufactured with VIII showed Tscm/Tcm enrichment, improved expansion and cytotoxicity in vitro and superior antitumor activity in vivo. Further, VIII induced AUTO1 Th1/Th17 skewing, increased polyfunctionality, and conferred a unique metabolic profile and a novel signature for autophagy to support enhanced expansion and cytotoxicity. We show that VIII-cultured AUTO1 products from B-ALL patients on the ALLCAR19 study possess superior phenotype, metabolism, and function than parallel control products and that VIII-based manufacture is scalable to cGMP. CONCLUSION: Ultimately, AUTO1 generated with VIII may begin to overcome the product specific factors contributing to CD19+relapse.

A survey of cancer genome signatures identifies genes connected to distinct chromosomal instability phenotypes.

Certain breast and ovarian cancers are characterised by high levels of chromosomal instability. We established a suite of eleven SNP array-based signatures of various forms of chromosomal instability. To understand what biological mechanisms might underpin these signatures, we generated and assembled genetic-feature data including allele-specific expression, fusion genes, gene expression, methylation, somatic coding mutations and protein expression. For each signature, we extracted a compendium of significantly associated genetic features using machine learning. We established an association between subchromosomal allelic imbalance-based measures and DNA repair genes. Numerical chromosomal instability and chromothripsis were found to have distinct genetic associations but shared a relationship to mitotic processes, while whole-genome doubling was characterised by TP53 mutation, and high AURKA and GINS1 expression. Furthermore, we identified two genetically distinct forms of tandem duplicator phenotypes. These findings identify potentially novel genomic targets for validation and drug development for specific subsets of breast and ovarian cancer.

Synthesis of Carboxamide-Containing Tranylcypromine Analogues as LSD1 (KDM1A) Inhibitors Targeting Acute Myeloid Leukemia.

Lysine-specific demethylase 1 (LSD1/KDM1A) oxidatively removes methyl groups from histone proteins, and its aberrant activity has been correlated with cancers including acute myeloid leukemia (AML). We report a novel series of tranylcypromine analogues with a carboxamide at the 4-position of the aryl ring. These compounds, such as 5 a and 5 b with benzyl and phenethylamide substituents, respectively, had potent sub-micromolar IC50 values for the inhibition of LSD1 as well as cell proliferation in a panel of AML cell lines. The dose-dependent increase in cellular expression levels of H3K4me2, CD86, CD11b and CD14 supported a mechanism involving LSD1 inhibition. The tert-butyl and ethyl carbamate derivatives of these tranylcypromines, although inactive in LSD1 inhibition, were of similar potency in cell-based assays with a more rapid onset of action. This suggests that carbamates can act as metabolically labile tranylcypromine prodrugs with superior pharmacokinetics.

Pembrolizumab for the treatment of progressive multifocal leukoencephalopathy following anti-CD19 CAR-T therapy: a case report.

Progressive multifocal leukoencephalopathy (PML) is an opportunistic brain infection with few treatment options and poor survival when reversal of the underlying immune dysfunction is not achievable. JC polyomavirus reactivation resulting in PML can rarely complicate chimeric antigen receptor T-cell (CAR-T) therapy. We describe successful treatment of PML with Programmed death-1 (PD-1) blockade using pembrolizumab, 4 months following axicabtagene ciloleucel. Radiological features of immune reconstitution inflammatory syndrome without clinical deterioration were seen. Evidence of anti-viral immune reconstitution by in vitro detection of JC-specific T-cells and sustained neurological recovery in this patient suggest PD-1 blockade may be an effective treatment approach for PML post-CAR-T.

Cellular Therapeutic Approaches to Cytomegalovirus Infection Following Allogeneic Stem Cell Transplantation.

Cytomegalovirus (CMV) infection is common following allogeneic hematopoietic stem cell transplant (HSCT) and is a major cause of morbidity and increased mortality. Whilst pharmacotherapy can be effective in the prevention and treatment of CMV, these agents are often expensive, toxic and in some cases ineffective due to viral resistance mechanisms. Immunotherapeutic approaches are compelling and early clinical trials of adoptively transferred donor-derived virus-specific T (VST) cells against CMV have demonstrated efficacy. However, significant logistical challenges limit their broad application. Strategies to optimize VST manufacture and cell banking alongside scientific developments to enhance efficacy whilst minimizing toxicity are ongoing. This review will discuss the development of CMV-specific T-cell therapies, the challenges of widespread delivery of VSTs for CMV and explore how VST therapy can change outcomes in CMV infection following HSCT.

Acute myeloid leukemia induces protumoral p16INK4a-driven senescence in the bone marrow microenvironment.

Acute myeloid leukemia (AML) is an age-related disease that is highly dependent on the bone marrow (BM) microenvironment. With increasing age, tissues accumulate senescent cells, characterized by an irreversible arrest of cell proliferation and the secretion of a set of proinflammatory cytokines, chemokines, and growth factors, collectively known as the senescence-associated secretory phenotype (SASP). Here, we report that AML blasts induce a senescent phenotype in the stromal cells within the BM microenvironment and that the BM stromal cell senescence is driven by p16INK4a expression. The p16INK4a-expressing senescent stromal cells then feed back to promote AML blast survival and proliferation via the SASP. Importantly, selective elimination of p16INK4a+ senescent BM stromal cells in vivo improved the survival of mice with leukemia. Next, we find that the leukemia-driven senescent tumor microenvironment is caused by AML-induced NOX2-derived superoxide. Finally, using the p16-3MR mouse model, we show that by targeting NOX2 we reduced BM stromal cell senescence and consequently reduced AML proliferation. Together, these data identify leukemia-generated NOX2-derived superoxide as a driver of protumoral p16INK4a-dependent senescence in BM stromal cells. Our findings reveal the importance of a senescent microenvironment for the pathophysiology of leukemia. These data now open the door to investigate drugs that specifically target the "benign" senescent cells that surround and support AML.

Myeloma-derived macrophage inhibitory factor regulates bone marrow stromal cell-derived IL-6 via c-MYC.

Multiple myeloma (MM) remains an incurable malignancy despite the recent advancements in its treatment. The protective effects of the niche in which it develops has been well documented; however, little has been done to investigate the MM cell's ability to 're-program' cells within its environment to benefit disease progression. Here, we show that MM-derived macrophage migratory inhibitory factor (MIF) stimulates bone marrow stromal cells to produce the disease critical cytokines IL-6 and IL-8, prior to any cell-cell contact. Furthermore, we provide evidence that this IL-6/8 production is mediated by the transcription factor cMYC. Pharmacological inhibition of cMYC in vivo using JQ1 led to significantly decreased levels of serum IL-6-a highly positive prognostic marker in MM patients. CONCLUSIONS: Our presented findings show that MM-derived MIF causes BMSC secretion of IL-6 and IL-8 via BMSC cMYC. Furthermore, we show that the cMYC inhibitor JQ1 can reduce BMSC secreted IL-6 in vivo, irrespective of tumor burden. These data provide evidence for the clinical evaluation of both MIF and cMYC inhibitors in the treatment of MM.

HIF1α drives chemokine factor pro-tumoral signaling pathways in acute myeloid leukemia.

Approximately 80% of patients diagnosed with acute myeloid leukemia (AML) die as a consequence of failure to eradicate the tumor from the bone marrow microenvironment. We have recently shown that stroma-derived interleukin-8 (IL-8) promotes AML growth and survival in the bone marrow in response to AML-derived macrophage migration inhibitory factor (MIF). In the present study we show that high constitutive expression of MIF in AML blasts in the bone marrow is hypoxia-driven and, through knockdown of MIF, HIF1α and HIF2α, establish that hypoxia supports AML tumor proliferation through HIF1α signaling. In vivo targeting of leukemic cell HIF1α inhibits AML proliferation in the tumor microenvironment through transcriptional regulation of MIF, but inhibition of HIF2α had no measurable effect on AML blast survival. Functionally, targeted inhibition of MIF in vivo improves survival in models of AML. Here we present a mechanism linking HIF1α to a pro-tumoral chemokine factor signaling pathway and in doing so, we establish a potential strategy to target AML.

NADPH oxidase-2 derived superoxide drives mitochondrial transfer from bone marrow stromal cells to leukemic blasts.

Improvements in the understanding of the metabolic cross-talk between cancer and its microenvironment are expected to lead to novel therapeutic approaches. Acute myeloid leukemia (AML) cells have increased mitochondria compared with nonmalignant CD34+ hematopoietic progenitor cells. Furthermore, contrary to the Warburg hypothesis, AML relies on oxidative phosphorylation to generate adenosine triphosphate. Here we report that in human AML, NOX2 generates superoxide, which stimulates bone marrow stromal cells (BMSC) to AML blast transfer of mitochondria through AML-derived tunneling nanotubes. Moreover, inhibition of NOX2 was able to prevent mitochondrial transfer, increase AML apoptosis, and improve NSG AML mouse survival. Although mitochondrial transfer from BMSC to nonmalignant CD34+ cells occurs in response to oxidative stress, NOX2 inhibition had no detectable effect on nonmalignant CD34+ cell survival. Taken together, we identify tumor-specific dependence on NOX2-driven mitochondrial transfer as a novel therapeutic strategy in AML.

Inflammatory Differences in Plaque Erosion and Rupture in Patients With ST-Segment Elevation Myocardial Infarction.

BACKGROUND: Plaque erosion causes 30% of ST-segment elevation myocardial infarctions, but the underlying cause is unknown. Inflammatory infiltrates are less abundant in erosion compared with rupture in autopsy studies. We hypothesized that erosion and rupture are associated with significant differences in intracoronary cytokines in vivo. METHODS AND RESULTS: Forty ST-segment elevation myocardial infarction patients with <6 hours of chest pain were classified as ruptured fibrous cap (RFC) or intact fibrous cap (IFC) using optical coherence tomography. Plasma samples from the infarct-related artery and a peripheral artery were analyzed for expression of 102 cytokines using arrays; results were confirmed with ELISA. Thrombectomy samples were analyzed for differential mRNA expression using quantitative real-time polymerase chain reaction. Twenty-three lesions were classified as RFC (58%), 15 as IFC (38%), and 2 were undefined (4%). In addition, 12% (12 of 102) of cytokines were differentially expressed in both coronary and peripheral plasma. I-TAC was preferentially expressed in RFC (significance analysis of microarrays adjusted P<0.001; ELISA IFC 10.2 versus RFC 10.8 log2 pg/mL; P=0.042). IFC was associated with preferential expression of epidermal growth factor (significance analysis of microarrays adjusted P<0.001; ELISA IFC 7.42 versus RFC 6.63 log2 pg/mL, P=0.036) and thrombospondin 1 (significance analysis of microarrays adjusted P=0.03; ELISA IFC 10.4 versus RFC 8.65 log2 ng/mL, P=0.0041). Thrombectomy mRNA showed elevated I-TAC in RFC (P=0.0007) epidermal growth factor expression in IFC (P=0.0264) but no differences in expression of thrombospondin 1. CONCLUSIONS: These results demonstrate differential intracoronary cytokine expression in RFC and IFC. Elevated thrombospondin 1 and epidermal growth factor may play an etiological role in erosion.

The bone marrow microenvironment - Home of the leukemic blasts.

Acute Myeloid Leukaemia (AML) is a genetically, biologically and clinically heterogeneous set of diseases, which are characterised by an increased growth of abnormal myeloid progenitor cells within the bone marrow (BM). Ex-vivo AML exhibits a high level of spontaneous apoptosis. Furthermore, relapse for patients achieving remission occurs from minimal residual disease harboured within the BM microenvironment. Taken together, these observations illustrate the importance of the BM microenvironment in sustaining AML. While significant progress has been made elaborating the small-scale genetic mutations and larger-scale chromosomal translocations that contribute to the development of AML and its prognosis in response to treatment, less is understood about the complex microenvironment of the BM, which is known to be a key player in the pathogenesis of the disease. As we look towards future therapies, the consideration that the BM microenvironment is uniquely important as a niche for AML - coupled with the idea that leukaemic blasts are more likely to be genetically unstable and therefore evolve resistance to conventional chemotherapies - make the functions of the non-malignant cells of the BM attractive targets for therapy. In this review, we discuss the microanatomy of the BM and provide an overview of the evidence supporting the role of the BM microenvironment in creating conditions conducive to the survival and proliferation of AML blasts. Ultimately, we examine the therapeutic potential of uncoupling AML from the BM microenvironment.

Leukemic blasts program bone marrow adipocytes to generate a protumoral microenvironment.

Despite currently available therapies, most patients diagnosed with acute myeloid leukemia (AML) die of their disease. Tumor-host interactions are critical for the survival and proliferation of cancer cells; accordingly, we hypothesize that specific targeting of the tumor microenvironment may constitute an alternative or additional strategy to conventional tumor-directed chemotherapy. Because adipocytes have been shown to promote breast and prostate cancer proliferation, and because the bone marrow adipose tissue accounts for up to 70% of bone marrow volume in adult humans, we examined the adipocyte-leukemia cell interactions to determine if they are essential for the growth and survival of AML. Using in vivo and in vitro models of AML, we show that bone marrow adipocytes from the tumor microenvironment support the survival and proliferation of malignant cells from patients with AML. We show that AML blasts alter metabolic processes in adipocytes to induce phosphorylation of hormone-sensitive lipase and consequently activate lipolysis, which then enables the transfer of fatty acids from adipocytes to AML blasts. In addition, we report that fatty acid binding protein-4 (FABP4) messenger RNA is upregulated in adipocytes and AML when in coculture. FABP4 inhibition using FABP4 short hairpin RNA knockdown or a small molecule inhibitor prevents AML proliferation on adipocytes. Moreover, knockdown of FABP4 increases survival in Hoxa9/Meis1-driven AML model. Finally, knockdown of carnitine palmitoyltransferase IA in an AML patient-derived xenograft model improves survival. Here, we report the first description of AML programming bone marrow adipocytes to generate a protumoral microenvironment.

MIF-Induced Stromal PKCß/IL8 Is Essential in Human Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) cells exhibit a high level of spontaneous apoptosis when cultured in vitro but have a prolonged survival time in vivo, indicating that tissue microenvironment plays a critical role in promoting AML cell survival. In vitro studies have shown that bone marrow mesenchymal stromal cells (BM-MSC) protect AML blasts from spontaneous and chemotherapy-induced apoptosis. Here, we report a novel interaction between AML blasts and BM-MSCs, which benefits AML proliferation and survival. We initially examined the cytokine profile in cultured human AML compared with AML cultured with BM-MSCs and found that macrophage migration inhibitory factor (MIF) was highly expressed by primary AML, and that IL8 was increased in AML/BM-MSC cocultures. Recombinant MIF increased IL8 expression in BM-MSCs via its receptor CD74. Moreover, the MIF inhibitor ISO-1 inhibited AML-induced IL8 expression by BM-MSCs as well as BM-MSC-induced AML survival. Protein kinase C ß (PKCß) regulated MIF-induced IL8 in BM-MSCs. Finally, targeted IL8 shRNA inhibited BM-MSC-induced AML survival. These results describe a novel, bidirectional, prosurvival mechanism between AML blasts and BM-MSCs. Furthermore, they provide biologic rationale for therapeutic strategies in AML targeting the microenvironment, specifically MIF and IL8. Cancer Res; 77(2); 303-11. ©2016 AACR.

PIM1 kinase regulates cell death, tumor growth and chemotherapy response in triple-negative breast cancer.

Triple-negative breast cancers (TNBCs) have poor prognosis and lack targeted therapies. Here we identified increased copy number and expression of the PIM1 proto-oncogene in genomic data sets of patients with TNBC. TNBC cells, but not nonmalignant mammary epithelial cells, were dependent on PIM1 for proliferation and protection from apoptosis. PIM1 knockdown reduced expression of the anti-apoptotic factor BCL2, and dynamic BH3 profiling of apoptotic priming revealed that PIM1 prevents mitochondrial-mediated apoptosis in TNBC cell lines. In TNBC tumors and their cellular models, PIM1 expression was associated with several transcriptional signatures involving the transcription factor MYC, and PIM1 depletion in TNBC cell lines decreased, in a MYC-dependent manner, cell population growth and expression of the MYC target gene MCL1. Treatment with the pan-PIM kinase inhibitor AZD1208 impaired the growth of both cell line and patient-derived xenografts and sensitized them to standard-of-care chemotherapy. This work identifies PIM1 as a malignant-cell-selective target in TNBC and the potential use of PIM1 inhibitors for sensitizing TNBC to chemotherapy-induced apoptotic cell death.

Targeting PI3Kδ and PI3Kγ signalling disrupts human AML survival and bone marrow stromal cell mediated protection.

Phosphoinositide-3-kinase (PI3K) is an enzyme group, known to regulate key survival pathways in acute myeloid leukaemia (AML). It generates phosphatidylinositol-3,4,5-triphosphate, which provides a membrane docking site for protein kinaseB activation. PI3K catalytic p110 subunits are divided into 4 isoforms; α,ß,δ and γ. The PI3Kδ isoform is always expressed in AML cells, whereas the frequency of PI3Kγ expression is highly variable. The functions of these individual catalytic enzymes have not been fully resolved in AML, therefore using the PI3K p110δ and p110γ-targeted inhibitor IPI-145 (duvelisib) and specific p110δ and p110γ shRNA, we analysed the role of these two p110 subunits in human AML blast survival. The results show that PI3Kδ and PI3Kγ inhibition with IPI-145 has anti-proliferative activity in primary AML cells by inhibiting the activity of AKT and MAPK. Pre-treatment of AML cells with IPI-145 inhibits both adhesion and migration of AML blasts to bone marrow stromal cells. Using shRNA targeted to the individual isoforms we demonstrated that p110δ-knockdown had a more significant anti-proliferative effect on AML cells, whereas targeting p110γ-knockdown significantly inhibited AML migration. The results demonstrate that targeting both PI3Kδ and PI3Kγ to inhibit AML-BMSC interactions provides a biologic rationale for the pre-clinical evaluation of IPI-145 in AML.

Activity of Bruton's tyrosine-kinase inhibitor ibrutinib in patients with CD117-positive acute myeloid leukaemia: a mechanistic study using patient-derived blast cells.

BACKGROUND: Roughly 80% of patients with acute myeloid leukaemia have high activity of Bruton's tyrosine-kinase (BTK) in their blast cells compared with normal haemopoietic cells, rendering the cells sensitive to the oral BTK inhibitor ibrutinib in vitro. We aimed to develop the biological understanding of the BTK pathway in acute myeloid leukaemia to identify clinically relevant diagnostic information that might define a subset of patients that should respond to ibrutinib treatment. METHODS: We obtained acute myeloid leukaemia blast cells from unselected patients attending our UK hospital between Feb 19, 2010, and Jan 20, 2014. We isolated primary acute myeloid leukaemia blast cells from heparinised blood and human peripheral blood mononuclear cells to establish the activity of BTK in response to CD117 activation. Furthermore, we investigated the effects of ibrutinib on CD117-induced BTK activation, downstream signalling, adhesion to primary bone-marrow mesenchymal stromal cells, and proliferation of primary acute myeloid leukaemia blast cells. We used the Mann-Whitney U test to compare results between groups. FINDINGS: We obtained acute myeloid leukaemia blast cells from 29 patients. Ibrutinib significantly inhibited CD117-mediated proliferation of primary acute myeloid leukaemia blast cells (p=0·028). CD117 activation increased BTK activity by inducing phosphorylated BTK in patients with CD117-positive acute myeloid leukaemia. Furthermore, ibrutinib inhibited CD117-induced activity of BTK and downstream kinases at a concentration of 100 nM or more. CD117-mediated adhesion of CD117-expressing blast cells to bone-marrow stromal cells was significantly inhibited by Ibrutinib at 500 nM (p=0·028) INTERPRETATION: As first-in-man clinical trials of ibrutinib in patients with acute myeloid leukaemia commence, the data suggest not all patients will respond. Our findings show that BTK has specific pro-tumoural biological actions downstream of surface CD117 activation, which are inhibited by ibrutinib. Accordingly, we propose that patients with acute myeloid leukaemia whose blast cells express CD117 should be considered for forthcoming clinical trials of ibrutinib. FUNDING: Worldwide Cancer Research, The Big C, UK National Institutes for Health Research, the Humane Research Trust, the Department of Higher Education and Research of the Libyan Government, and Norwich Research Park.

Ibrutinib inhibits SDF1/CXCR4 mediated migration in AML.

Pharmacological targeting of BTK using ibrutinib has recently shown encouraging clinical activity in a range of lymphoid malignancies. Recently we reported that ibrutinib inhibits human acute myeloid leukemia (AML) blast proliferation and leukemic cell adhesion to the surrounding bone marrow stroma cells. Here we report that in human AML ibrutinib, in addition, functions to inhibit SDF1/CXCR4-mediated AML migration at concentrations achievable in vivo. It has previously been shown that SDF1/CXCR4-induced migration is dependent on activation of downstream BTK in chronic lymphocytic leukaemia (CLL) and multiple myeloma. Here we show that SDF-1 induces BTK phosphorylation and downstream MAPK signalling in primary AML blast. Furthermore, we show that ibrutinib can inhibit SDF1-induced AKT and MAPK activation. These results reported here provide a molecular mechanistic rationale for clinically evaluating BTK inhibition in AML patients and suggests that in some AML patients the blasts count may initially rise in response to ibrutinib therapy, analgous to similar clinical observations in CLL.