An animal model of MGUS/SMM to investigate the role of cellular senescence in progression to MM

8050

Background: Multiple Myeloma (MM) is an incurable cancer of plasma cells that arises from precursor stages, monoclonal gammopathy of undetermined significance (MGUS) and/or smoldering MM (SMM). Mechanisms for the transformation of MGUS/SMM to MM are not fully known. There is no approved therapy for MGUS/SMM and research is limited by a lack of animal models. Here, we describe the use of a novel animal model of disease progression derived from patients with MGUS/SMM to study the impact of cellular senescence (CS) on the development of MM. Methods: CD 138+ plasma cells and CD138- stromal cells were isolated via magnetic beads from bone marrow aspirates of patients with MGUS/SMM and co-cultured CD138+/CD138- with different ratios. For the animal model CD138+/CD138- cells from MGUS/SMM patients were injected into the tibias of NSG mice (1:10). After 4 weeks, CD138+ cells were harvested and again co-transplanted into the tibia of a 2nd NSG mouse with the CD138- cells (1:10). Mice underwent serial imaging and tibias were histologically examined after 4 weeks in the 2nd mouse. CS gene expression was compared by RNAseq between patients with SMM and healthy older adults. The primary CD138- cells were stained for SA-β-gal. Human mesenchymal stem cells (hMSCs) induced by H2O2 for CS vs control were co-cultured with CD138+ cells. Patient derived CD138- cells were treated with anti-senolytic drugs, dasatinib (D) and quercetin (Q) and cell growth in co-culture with CD138+ plasma cells was measured. D+Q treated patient-derived CD138+/CD138- cells were co-transplanted into our NSG mouse model and followed with serial imaging. Results: CD138- stromal cells from patients with MGUS/SMM support the growth of CD138+ plasma cells (10:1). CD138- cells were found to gain CD138+ expression, suggesting another source for the plasma cell growth. Imaging of our mouse model showed the development of lytic lesions in the tibias of 5/5 mice versus no lytic lesions in mice transplanted with CD138+ cells alone. Staining of the lytic lesions revealed CD138+ plasma cells. Our RNA seq showed significantly increased expression of CS genes, CDKN2A, p16 and p19 (3 fold) in CD138- cells of SMM patients and confirmed by qPCR (8 fold) compared to healthy older adults. The primary stromal cell culture from MGUS/SMM patients showed the presence of SCs by SA-β-gal staining. H2O2 induced senescent hMSCs stimulate cell survival and growth of CD138+ cells. CD138- cells cultured with conditioned media from H2O2 induced hMSCs demonstrated more CD138+ cells than vehicle treated CD138- cells. Conversely, D + Q pre-treated CD138- cells lost the ability to promote CD138+ cells in co-culture. Our animal model treated with D+Q showed less bone erosion in tibias compared to untreated mice. Conclusions: Our work demonstrates a novel animal model for studying disease progression in patients with MGUS or SMM and demonstrates a role for CS in MM disease progression.

Effect of auranofin on oxidative and endoplasmic reticulum stress as well as anti-CLL activity with proteasome inhibitor

e13568

Background: The gold-containing compound auranofin (AF) (Ridaura), is a treatment of rheumatoid arthritis. Recently, AF was shown to inhibit thioredoxin reductase (TRR), increase reactive oxygen species (ROS) and induce apoptosis in cancer cells. Methods: We determined the ability of AF (250 to 1000 nM) to induce oxidative, proteotoxic and lethal endoplasmic reticulum (ER) stress in CD19+ primary CLL cells, including those with deletion of chromosome 17p. Results: Treatment with AF induced 20 to 40% increase in ROS levels, decreased TRR activity (mean of 45%), but not its protein expression, in CLL cells. AF-mediated oxidative stress induced NRF2 activity with increase in hemeoxygenase-1 (HO-1) and glutamate cysteine ligase modifier (GCLM) levels. AF induced ER stress, associated with increase in GRP78 and the pro-apoptotic transcription factor CHOP protein levels. AF also induced the pro-apoptotic BH3-only domain protein BIM. Exposure to AF increased the intracellular levels of misfolded polyubiquitylated proteins. This disrupted the binding of heat shock protein (hsp) 90 with histone deacetylase 6 (HDAC6), resulting in hyperacetylation and inhibition of the chaperone function of hsp90. This led to proteasomal degradation of CLL-relevant hsp90 client proteins, including ZAP70, c-Raf and AKT. Nuclear STAT3 levels also declined. Exposure to AF induced significantly more apoptosis (range 40 to 60%) in primary CLL cells, as compared to CD19+ normal B cells and CD34+ human cord blood and bone marrow progenitor cells (< 15% apoptosis) (p < 0.01). AF treatment also induced apoptosis in CD19+ cells from patients with poor prognosis CLL with deletion of 17p or with deletion of 13q. Co-treatment with AF and the proteasome inhibitor carfilzomib or the GCLM antagonist buthionine sulfoximine (BSO) synergistically induced apoptosis in primary CLL cells. A FDA IND-supported phase II clinical trial of AF (6 to 9 mg PO/day) with correlative biomarker analysis (as above) is underway and three patients are enrolled. Conclusions: These findings support the full evaluation of clinical activity and predictive biomarkers of response to the re-purposed AF in patients with CLL.

Anti-AML activity of a novel beta-catenin antagonist BC2059

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Background: The canonical WNT-β-catenin pathway is essential for self-renewal, growth and survivalof AML stem and progenitor cells. Deregulated WNT signaling inhibits degradation of β-catenin, causing increased nuclear translocation and interaction of β-catenin with the TCF/LEF transcription factor, which up regulates cyclin D1, Myc and survivin expression in AML progenitor cells. BC2059 (β-Cat Pharmaceuticals) is a potent, small molecule, anthraquinone oxime-analog, which inhibits WNT-β catenin pathway by promoting the degradation and attenuation of β-catenin levels. Methods: We determined the in vitro anti-AML activity of BC2059 (BC) (250 to 1000 nM) against cultured and primary human AML blast progenitors, as well as evaluated the in vivo anti-AML efficacy of BC in NOD-SCID and NOD-SCID-IL2γ receptor deficient (NSG) mice. Results: BC induced cell cycle G1 phase accumulation and apoptosis (40%) of the cultured OCI-AML3, HL-60 and HEL92.1.7 (HEL) AML cells. BC dose-dependently also induced apoptosis of primary AML versus normal progenitors. Treatment with BC resulted in proteasomal degradation and decline in the nuclear levels of β-catenin, which led to decreased activity of the LEF1/TCF4 transcription factor highlighted by reduced TOP-FLASH luciferase activity in the AML cells. This was associated with reduced protein levels of cyclin D1, MYC and survivin. Co-treatment with BC and the histone deacetylase inhibitor panobinostat (PS) (10 to 20 nM) synergistically induced apoptosis of cultured and primary AML blasts. Following tail vein infusion and establishment of AML by OCI-AML3 or HEL cells in NOD-SCID mice, treatment with BC (5, 10 or 15 mg/kg b.i.w, IV) for three weeks demonstrated improved survival, as compared to the control mice (p <0. 001). Survival was further improved upon co-treatment with BC and PS (5 mg/kg IP, MWF). BC treatment (5 or 10 mg/kg IV) also dramatically improved survival of NSG mice with established human AML following tail-vein injection of primary AML blasts expressing FLT3 ITD. Mice did not experience any toxicity or weight loss. Conclusions: These findings highlight the notable pre-clinical in vitro and in vivo activity and warrant further development and in vivo testing of BC against human AML.

Late-onset intestinal perforation in the setting of posttransplantation microangiopathy: a case report

Intestinal perforation in the setting of posttransplantation microangiopathy (TMA) is a very rare event and might be considered a terminal event of intestinal microangiopathy (i-TMA), a rather rarely recognized posttransplantation complication, as it overlaps with the more common intestinal graft-versus-host disease (GVHD). Cases of i-TMA described in literature occurred within with first 100 days posttransplantation or shortly thereafter. In this report, we describe a case of late-onset intestinal perforation that occurred in the setting of systemic microangiopathy more than a year after allogeneic transplantation. In our case, the patient poorly responded to treatment secondary to refractory mircoangiopathy.

Low-dose cidofovir in the treatment of symptomatic BK virus infection in patients undergoing allogeneic hematopoietic stem cell transplantation: a retrospective analysis of an algorithmic approach

BK virus (BKV) reactivation occurs in 50% of allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. Standardized antiviral management of BKV infection has not been established. In order to develop a uniform guideline, a treatment algorithm for the management of symptomatic BKV replication was implemented for our allo-HSCT population. This is a retrospective analysis of patients treated according to the protocol between January 2008 and January 2009. Eighteen patients developed symptomatic BKV replication a median of 43 days after allo-HSCT. All patients had BK viruria and 12 patients had BK viremia in addition to viruria. Patients with isolated viruria were treated with intravenous (IV) low-dose cidofovir (0.5-1mg/kg IV weekly) until symptom resolution. In patients with BK viremia, therapy was continued until virological clearance was achieved in the blood. Four patients also received intravesical instillation of cidofovir per physician discretion. Thirteen of 18 (72%) patients with viruria and 8 of 12 (75%) patients with viremia responded to treatment. Three patients developed transient renal dysfunction. Low-dose cidofovir is safe and effective in allo-HSCT recipients. In absence of randomized prospective data, an institutional algorithmic protocol removes variance in practice pattern and derives data that may be used for research and improved patient care.

Blastic plasmacytoid dendritic cell neoplasm should be treated with acute leukemia type induction chemotherapy and allogeneic stem cell transplantation in first remission

Blastic plasmacytoid dendritic cell (BPDC) neoplasm is a rare but clinically aggressive tumor known to be derived from the precursors of plasmacytoid dendritic cells (CD123+) with a high frequency of cutaneous and bone marrow involvement. Though majority of the patients initially respond to multi-agent chemotherapy, most would relapse within a year. We hereby report a patient with disseminated cutaneous BPDC with marrow involvement diagnosed by typical histo-pathological and flow-cytometric findings. He was subsequently treated with leukemia type induction regimen followed by allogeneic stem cell transplantation in first complete remission. He is now 18 months posttransplantation with continued remission with full donor chimerism. We recognize that BPDC with marrow involvement behaves like acute myeloid leukemia and aggressive treatment followed by stem cell transplantation may lead to long-term remission in selected cases.

Serologically documented loracarbef (Lorabid)-induced immune thrombocytopenia

We report here the first case of severe immune thrombocytopenia induced by a second-generation cephalosporin antibiotic, Loracarbef. A 56-year old white female developed acute severe thrombocytopenia associated with acute respiratory symptoms following administration of Loracarbef. She responded to Loracarbef withdrawal and systemic corticosteroid administration. Loracarbef-dependent platelet-reactive antibodies were demonstrable in her serum by flow cytometry.