ALBERT

Description: Introduction Mutant NRAS and KRAS lead to the activation of the RAS/RAF/MEK/ERK pathway in approximately 50% of multiple myeloma (MM). Blocking this pathway with MEK1/2 inhibitors (MEKi) such as trametinib (Tram) is a therapeutic option but the response rate in MM varies between 30-50% (Heuck et al, Leukemia 2015). In MM it is unknown whether RAS mutation status correlates with sensitivity to Tram. The purpose of this study was to characterize factors which predict response to Tram and to identify mechanism mediating resistance. Methods We established the IC50 of Tram using MTT assays in 32 MM cell lines (HMCL) including 16 RAS mutant positive (RASm+), and 15 wildtype RAS (RASm-), and 1 BRAF mutant (BRAFm+) line which acted as a positive control. HMCLs were classified according to the IC50 value as sensitive (10μM). All lines underwent immunoblotting for pERK at baseline and following treatment with serial concentrations of Tram to identify correlation of activation with sensitivity. BrdU incorporation analyzed by FACS was performed to determine the molecular action of Tram. A lentiviral mediated expression system was used to engineer a MAF overexpressing cell line in a RASm+ HMCL lacking MAF (MMRASm+MAF) and silencing MAF in two lines with co-occurring MAF and RASm+ (MMRASm+shMAF). The clinical characteristics of 84 relapsed RASm+ patients who received Tram either as a single agent or in combination with other anti-MM therapies were also examined. Results 6/16 (37.5%) of RASm+ HMCLs were sensitive to Tram, 5/16 (31.1%) were IMS and 5/16 (31.1%) resistant. There was no difference in sensitivity to Tram between KRASm+ (IC50 = 9.5μM, n = 11) and NRASm+ (IC50 =12.5μM, n=4, p=0.65). In contrast, 13/15 (87%) RASm- HMCLs were resistant to Tram. Mechanistically, Tram blocked cell cycle progression in Tram-sensitive RASm+ cells with an increase in G0/G1 phase (22.25%) and a decrease in S phase (16.76%) compared with untreated controls (p

Description: Key Points Immune responses to FVIII sequence variants encoded by ns-SNPs do not contribute appreciably to inhibitor development in African Americans. African American HA subjects with an intron-22 inversion had a 2- to 3-times-higher inhibitor incidence than whites with the same mutation.

Description: Background: Activating mutations of NRAS and KRAS genes are common in newly diagnosed acute myeloid leukemia (AML), occurring in 11-16% and 4-5% of patients, respectively. RAS mutations are frequently acquired at time of progression from MDS to AML and are associated with poor survival. Next generation sequencing (NGS) at diagnosis and during complete remission has shown that RAS mutations have high clearance rates with induction chemotherapy. In the CALGB 8525 study, RAS-mutant younger patients (age

Description: Juvenile and chronic myelomonocytic leukemias (JMML and CMML) are aggressive myeloid malignancies categorized as myelodysplastic syndromes/myeloproliferative neoplasms (MDS/MPN). Chemotherapy has little benefit for MDS/MPN patients, and new therapies are needed. We have used mouse models investigate the potential of signal transduction inhibitors in MDS/MPN, as JMML and CMML are associated with mutations in NRAS, KRAS, PTPN11, CBL, or NF1 that activate Ras signaling. Conditional Mx1-Cre, KrasLSL-D12 (designated KrasD12) mice develop an aggressive and fully penetrant MDS/MPN characterized by leukocytosis, splenomegaly, anemia, and death by 10-16 weeks of age. Mx1-Cre, Nf1flox/- mice (hereafter Nf1Δ/-) undergo conditional loss of Nf1. These mice also develop MDS/MPN, but the disease is more indolent. We and others have investigated inhibition of effector networks downstream of Ras, such as the Raf/MEK/ERK (MAPK) and phosphotidylinositol-3 kinase (PI3K)/Akt pathways. We previously showed that the MEK inhibitor PD0325901 induced sustained hematologic improvement in both KrasD12 and Nf1Δ/- mice. We also have reported that the class I PI3K inhibitor GDC-0941 improves hematologic function and prolongs survival in KrasD12 mice. However, GDC-0941 and other PI3K inhibitors attenuate both PI3K/Akt and Raf/MEK/ERK pathways due to effects of PI3K upstream of Ras. Therefore, the benefit from GDC-0941 could have been due to its modulation of Raf/MEK/ERK signaling. Here, we specifically test the importance of Akt signaling in MDS/MPN in KrasD12 and Nf1 mouse models using the allosteric inhibitor MK-2206. This compound binds to the interface of the PH and kinase domains of Akt1, Akt2, and Akt3, and does not inhibit any of 250 other kinases at 1 µM. MK-2206 induced substantial improvement in both KrasD12 and Nf1Δ/- mice. Mice treated with MK-2206 had pronounced reduction in leukocytosis, reticulocytosis and splenomegaly, increased hemoglobin concentration, and prolonged survival. MK-2206 had no hematologic effects in control WT mice, indicating some selectivity against aberrant hematopoiesis. Importantly, MK-2206 inhibited Akt but not Raf/MEK/ERK or Jak/STAT signaling. This demonstrates that canonical PI3K/Akt signaling plays an important role in Ras-driven MDS/MPN. Furthermore, combined inhibition of MEK and Akt with PD0325901+MK-2206 yielded a greater improvement in splenomegaly than either agent alone in both KrasD12 and Nf1Δ/- models. Akt has multiple effectors relevant to hematopoiesis and leukemia. Of these, mTOR is of particular interest for targeted cancer therapy. Therefore, we tested the response of KrasD12 mice to rapamycin, a partial inhibitor of mTOR with preferential activity against the mTORC1 complex. KrasD12 mice demonstrated variable responses to rapamycin, with approximately half undergoing a complete and durable hematologic response and the remainder having no response. Together, these studies further implicate PI3K/Akt signaling as a pathogenic effector downstream of Ras in MDS/MPN and support the idea that inhibitors targeting this pathway may have a role in treatment of JMML or CMML. Disclosures No relevant conflicts of interest to declare.

Description: Background Measurable residual disease (MRD) is associated with inferior outcomes in patients with acute myeloid leukemia (AML). MRD monitoring enhances risk stratification and may guide therapeutic intervention. Post-induction MRD is frequently cleared with further therapy and the clearance may lead to better outcomes. In contrast, persistent MRD is associated with poor outcomes. At present it is not possible to predict which patients are likely to clear MRD with further therapy. Here we report a simple, objective, widely applicable and quantitative MFC approach using the ratio of blast/PDC to predict persistent MRD and poor outcomes in AML. Patients and Methods A cohort of 136 adult patients with a confirmed diagnosis of AML by WHO criteria who underwent standard induction therapy at a single center between 4/2014 and 9/2017 was initially included. 69 patients achieved complete morphologic remission (36 MRD-neg. and 33 MRD-pos.). MRD status was assessed by MFC using a different from normal (DfN) approach. PDC were quantified as the percent of total WBC by flow cytometry based on low side scatter, moderate CD45, CD303, bright CD123 and HLA-DR expression. Results The proportion of PDC was markedly decreased in patients with AML (≥20% blasts) (N=136) with a median of 0.016% (interquartile range IQR: 0.0019%-0.071%, Figure 1A), more than 10-fold lower than observed in normal controls (median 0.23%, IQR 0.17%-0.34%) (N=20). While there was no difference between MRD-neg. and normal control groups (median 0.31%, IQR: 0.17%-0.49%; vs. 0.28%, IQR: 0.17%-0.34%), MRD-pos. group had significantly reduced PDC proportion compared to the control (median 0.074%, IQR: 0.022%-0.33%, Wilcoxon rank sum, p=0.019). In an attempt to achieve better separation and to eliminate possible effects of hemodilution, the ratio of blast/PDC was calculated by using the proportions of blasts and PDCs out of total WBCs as quantitated by flow cytometry. A cut-off threshold of the blast/PDC ratio of 10 was chosen to separate each group (Figure 1B). Importantly, a ratio cut-off of 10 had a corresponding specificity of 97.4% for predicting MRD positivity status. MRD positivity was significantly associated with inferior overall survival (OS) and relapse-free survival (RFS) in our study cohort (OS HR 4.11 (95% CI: 1.30-13.03), p=0.016; RFS HR 4.20 (95% CI: 1.49-11.82), p=0.007, Figure 1C and D). The 2-year cumulative incidence of relapse in the MRD-neg. group compared to MRD-pos. group was 10% (95% CI: 2-24%) vs. 37% (95% CI: 18-56%, p=0.014). Importantly, blast/PDC ratio ≥10 was also strongly associated with inferior OS and RFS (OS HR 3.12 (95% CI: 1.13-8.60), p= 0.028; RFS HR 4.05 (95% CI: 1.63-10.11), p=0.003, Figure 1E and F), which is similar in magnitude to MRD positivity. Furthermore, MRD-pos. patients with blast/PDC ratio

Description: Introduction Chromosome instability (CIN) is a driver of copy number aberrations (CNAs) in cancer, and is a major factor leading to tumor heterogeneity and resistance to therapy. By definition, CIN is an increased rate or ongoing acquisition and accumulation of CNAs and not simply the existence of structurally and numerically abnormal aneuploid clones. In multiple myeloma (MM), the most common whole-chromosome CNAs involve either hyperdiploid or non-hyperdiploid clones. Secondary segmental CNAs are associated with high-risk (HR) in MM and involve gains of 1q21 and deletions of 17p (del17p). These types of intra-chromosomal segmental CNAs are also found in the CIN phenotypes of the autosomal recessive (AR) chromosome instability syndromes. These syndromes include Fanconi anemia, Bloom's syndrome, and ICF syndrome (Immunodeficiency, Centromeric instability and Facial anomalies). These chromosome instability syndromes display a spectrum of aberrations characterized by higher rates of chromosomal breaks, chromatid exchanges, quadriradials, and pericentromeric aberrations. In particular, patients with ICF syndrome show a marked increase of 1q12 pericentromeric instability including 1q12 decondensation, triradials, multibranched chromosomes 1q, and 1q micronuclei. ICF patients also show transient 1q aberrations including isochromosome 1q (iso1q) and unbalanced translocations of 1q to 9q and 16q. In MM, we have previously reported increasing pericentromeric instability during tumor progression resulting in increasing CNAs of 1q21 by unbalanced jumping translocations of 1q12 (JT1q12). Strikingly, in a subset of MM patients with 1q21 CNAs of ≥ 5 a distinct cytogenetic phenotype emerges which demonstrates transient 1q12 aberrations including 1q12 decondensation, triradials, and multibranched chromosomes 1q morphologically identical to those seen in ICF patients. In MM this chromosome instability leads to a cascade of increasing clonal 1q21 duplications, iso 1qs, and unbalanced 1q translocations with 16q and 17p, resulting in losses in these receptor chromosomes (RC) and massive intra-clonal CNA heterogeneity. Methods To investigate the cytogenetic impact and progression of high CNAs of 1q21, we performed a comprehensive metaphase analysis of 50 patients showing segmental aneuploidies with 4 or more copies of 1q by G-banding. Locus specific FISH and spectral karyotyping were used to identify the key transient unstable and clonal structural aberrations of 1q12 resulting in segmental aneuploidies in the derivative RCs. Probe for 1q12 (Vysis) was used according to the manufacturer's protocol. Locus specific BAC clones for 1q21 (CKS1B) and 17p (TP53) were prepared and analyzed as previously described (Sawyer et al., Blood 123: 2014). IGH translocations were investigated with IGH break apart probes (Vysis). Results Data for 50 patients including CNAs of 1q21 of ≥ 4, IGH translocations, del(17p), derivative RCs, are presented. The t(4;14) was found in 15 patients, del(17p) in 23, and both aberrations were found in 8 patients. All patients showed unbalanced gains of 1q and deletions of RCs, the most frequent being 7 patients with der(1;16) and 6 with iso1q. In four of the 23 patients with del(17p), the deletion was due to a JT1q12 to 17p. Seven patients with 1q21 CNAs of ≥ 5 showed profound instability involving the 1q12 satellite DNA, demonstrating both transient and clonal aberrations driving the 1q21 CNAs. These aberrations included unstable 1q21 triplications, JT1q12s, iso1q formation with intra-arm 1q12 CNAs, and region specific breakage-fusion-bridge cycle amplifications. Conclusions Among patients with ≥ 5 CNAs of 1q21, a subset develop an acquired HR chromosome instability phenotype with an elevated rate of 1q12 pericentromeric instability characterized by concomitant deletions in 16q, iso1q, del(17p), and intra-arm segmental instability. These patients show pronounced instability in the 1q12 satellite DNA, morphologically identical to ICF syndrome, suggesting hypomethylation of this region as a driver of both 1q21 CNAs and deletions in RCs. We hypothesize that region specific hypomethylation of 1q12 provides the genomic background for the onset of an acquired 1q12 chromosome instability phenotype in MM similar to that found in ICF syndrome. For myeloma patients demonstrating this 1q12 chromosome instability phenotype we propose the term "jumping 1q syndrome." Disclosures Epstein: University of Arkansas for Medical Sciences: Employment. Davies:Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; ASH: Honoraria; Abbvie: Consultancy; TRM Oncology: Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; MMRF: Honoraria; Janssen: Consultancy, Honoraria. Morgan:Takeda: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria.

Description: Sickle cell disease (SCD) results in chronic hypoxia and secondarily increased erythropoietin concentrations. Leukocytosis and activated monocytes are also observed in SCD in absence of infection or vaso-occlusion (steady state), the reasons for which are unknown. We found that erythroid cells produced placenta growth factor (PlGF), an angiogenic growth factor belonging to the vascular endothelial growth factor (VEGF) family, and its expression was induced in bone marrow CD34+ progenitor cells in the presence of erythropoietin. Furthermore, the steady state circulating PlGF levels in subjects with severe SCD (at least 3 vaso-occlusive crises [VOCs] per year) were 18.5 ± 1.2 pg/mL (n = 9) compared with 15.5 ± 1.2 pg/mL (n = 13) in those with mild SCD (fewer than 3 VOCs per year) and 11.3 ± 0.7 pg/mL (n = 9) in healthy controls (P 〈 .05), suggesting a correlation between PlGF levels and SCD severity. In addition, PlGF significantly increased mRNA levels of the proinflammatory cytochemokines interleukin-1β, interleukin-8, monocyte chemoattractant protein-1, and VEGF in peripheral blood mononuclear cells (MNCs) of healthy subjects (n = 4; P 〈 .05). Expression of these same cytochemokines was significantly increased in MNCs from subjects with SCD at steady state (n = 14), compared with healthy controls. Of the leukocyte subfractions, PlGF stimulated monocyte chemotaxis (P 〈 .05, n = 3). Taken together, these data show for the first time that erythroid cells intrinsically release a factor that can directly activate monocytes to increase inflammation. The baseline inflammation seen in SCD has always been attributed to sequelae secondary to the sickling phenomenon. We show that PlGF contributes to the inflammation observed in SCD and increases the incidence of vaso-occlusive events.

Description: Syndecan-1 (CD138) is a transmembrane heparan sulfate–bearing proteoglycan expressed by most myeloma plasma cells that regulates adhesion, migration, and growth factor activity. In patients with myeloma, shed syndecan-1 accumulates in the bone marrow, and high levels of syndecan-1 in the serum are an indicator of poor prognosis. To test the effect of soluble syndecan-1 on tumor cell growth and dissemination, ARH-77 B-lymphoid cells were engineered to produce a soluble form of syndecan-1. Controls included vector only (neo)–transfected cells and cells transfected with full-length syndecan-1 complementary DNA that codes for the cell surface form of syndecan-1. Assays reveal that all 3 transfectants have similar growth rates in vitro, but cells expressing soluble syndecan-1 are hyperinvasive in collagen gels relative to controls. When injected into the marrow of human bones that were implanted in severe combined immunodeficient mice, tumors formed by cells expressing soluble syndecan-1 grow faster than tumors formed by neo-transfected cells or by cells expressing cell surface syndecan-1. In addition, cells bearing cell surface syndecan-1 exhibit a diminished capacity to establish tumors within the mice as compared with both neo- and soluble syndecan-1–transfected cells. Tumor cell dissemination to a contralateral human bone is detected significantly more often in the tumors producing soluble syndecan-1 than in controls. Thus, high levels of soluble syndecan-1 present in patients with myeloma may contribute directly to the growth and dissemination of the malignant cells and thus to poor prognosis.

Description: cAMP-mediated signaling potentiates glucocorticoid-mediated apoptosis in lymphoid cells, but an effective means by which to take advantage of this observation in the treatment of lymphoid malignancies has not been identified. The PDE4 enzyme family regulates the catabolism of cAMP to AMP in a wide range of tissues. PDE4 inhibitors have recently been submitted for approval for use in asthma and COPD. In leukemic samples from 11 B-CLL patients, rolipram and RO20-1724, two structurally unrelated PDE4 inhibitors, synergized with either hydrocortisone or dexamethasone in inducing B-CLL but not T cell apoptosis. Dose titration studies demonstrated that addition of a PDE4 inhibitor augmented B-CLL apoptosis even when maximally effective doses of either glucocorticoid were utilized. In five patients so analyzed, 10 uM rolipram augmented the induction of apoptosis by 100 uM hydrocortisone by 40 +/− 18%. Using transient transfection of a GRE-luciferase construct with an Amaxa nucleofector technique, we determined that treatment with PDE4 inhibitors augmented glucocorticoid receptor (GR)-mediated GRE transactivation in primary B-CLL cells. Strikingly, inhibition of PKA with the cAMP antagonist Rp-8Br-cAMPS inhibited glucocorticoid-induced apoptosis by 86 +/− 14% in 6 patients so tested and GRE transactivation by 83% in 8 patients so tested. Similarly, treatment with Ht31 peptide, a 23 residue peptide derived from an AKAP that binds with 4.0 nM dissociation constant to PKA RII subunits, also reduced hydrocortisone-induced transactivation. These studies suggest that PKA activity is required for both the ability of glucocorticoids to induce apoptosis and GRE transactivation in B-CLL cells. CCRF-CEM cells, a well-studied model of glucocorticoid and cAMP-induced apoptosis, differed from B-CLL cells in that stimulation of adenylyl cyclase with the diterpene forskolin was required to increase both glucocorticoid-mediated apoptosis and GRE activation, while PDE4 inhibition had no effect. We isolated both dexamethasone-sensitive and dexamethasone-resistant CCRF-CEM clones for these studies and demonstrated that forskolin induced glucocorticoid sensitivity even in the initially dexamethasone resistant clone. 1,9 dideoxyforskolin, a forskolin analogue that does not activate adenylyl cyclase, failed to augment glucocorticoid sensitivity in CCRF-CEM cells. Given the marked discrepancy in the sensitivity of B-CLL cells and CCRF-CEM cells to PDE4 inhibitor-induced augmentation of glucocorticoid apoptosis and GRE transactivation, we next examined the cAMP response and PDE4 isoforms in these two cell types. Inhibition of PDE4 induced cAMP elevation in B-CLL but not CCRF-CEM cells, while forskolin augmented cAMP levels in CCRF-CEM but not B-CLL cells. While rolipram but not forskolin treatment up-regulated 63 and 68 kDa forms of PDE4B (most likely PDE4B2) in B-CLL, forskolin but not rolipram treatment up-regulated 67 and 72 kDa forms of PDE4D (most likely PDE4D1/D2) in CCRF-CEM cells. These studies suggest that PKA is required for and enhances glucocorticoid-induced apoptosis in B-CLL by modulating GR signal transduction and that inhibition of PDE4 in the absence of exogenous adenylyl cyclase activation is a clinically tenable means by which to achieve such PKA activation. Clinical trials that examine whether PDE4 inhibitors enhance the efficacy of glucocorticoid-containing chemotherapy regimens in B-CLL and other lymphoid malignancies are indicated.

Description: We have performed 2,000+ Fluorodeoxyglucose PET (PET) scans for multiple myeloma (MM) staging and restaging at our facility since October 2001. While the usefulness of the PET scan for MM is reported by us and others elsewhere, we have reviewed our list of “incidental” but important findings, some of which are unique or occur more commonly with MM patients and some of which are common to many patients, the more common of which we present below: Occult infection occurs very commonly in patients with MM due to direct tumor effect on the immune system and to medication (especially high dose dexamethasone). Of the 2000+ PET scans for MM done at our facility, 300+ infections (about one half occult) have been detected by PET. These most commonly involve central lines (septic thrombophlebitis), diskitis, lung (either bacterial or fungal), and periodontal abscesses (a source of bacteremia in these patients), though non-catheter related spontaneous septic thrombophlebitis also occurs. While related to MM, extramedullary disease from MM (EMD) is seen more commonly with PET than MRI since PET has a wider field of view. In our series of 172 patients with both baseline PET and MRI, PET detected EMD in 11/11 patients versus MRI detection rate of 7/11. On follow-up, PET detected three times more EMD (29/31 sites) than MRI (9/31sites). Detection of EMD by PET at baseline is a profoundly negative prognostic factor in our series (12 month EFS 20% for EMD+ vs. 47% for EMD−, p = 0.002, and OS 42% for EMD+ vs. 70% for EMD−, p=0.005, n=48). Following tumor response in hypo- or non-secretory disease is difficult by standard prognostic factors (SPFs). FDG PET results were actively used for clinical management in 10 of 11 non-secretory patients at our facility. A major pitfall of PET scanning for MM comes from the use of steroids. Treatment with chemotherapy in general and steroids (i.e. prednisone or dexamethasone) in particular can result in a false negative PET scan by producing a profound but transient suppression of tumor metabolism. In addition, the hyperglycemic effect of the steroids produces competitive inhibition of FDG (a glucose analog) uptake, also causing suppression of FDG tumor uptake that can lead to an underestimation of disease. Second primary malignancies are frequently seen the MM age group. In our population, we have found unsuspected breast cancer, breast lymphoma, thyroid cancer, melanoma, colon cancer and lung cancer. In addition, we have found several functioning thyroid adenomas and premalignant colon polyps. Being a whole body imaging device for metabolism, FDG PET is a powerful though nonspecific tool for imaging that can not only help stage and restage the malignancy under question but which can yield a plethora of additional clinically useful information if used properly and with its limitations understood.