High Glycine Promotes Proliferation and Progression Though Increase of Glutathione Synthesis in Multiple Myeloma

Background: Metabolites in tumor microenvironment have been confirmed to contribute to cancer progression. Our previous untargeted metabolomics study has indicated that glycine was significantly increased in bone marrow and peripheral blood derived from Multiple Myeloma(MM) patients compared with health donors(HD). However, the role of glycine in MM progression and its underling mechanisms remain unclear. Materials and Methods: Liquid chromatography-mass spectrometry (LC-MS) was used to detect the concentration of glycine in peripheral blood derived from (25) MM patients and (21) HD. Metabolic flux experiment was performed to explore the distribution of exogenous glycine in MM cell lines ARP1 and 5TGM1. Soft agar colony formation and cell cycle assay were performed to detect MM cells proliferation. 5TGM1 MM mouse models were prepared to examined the effect of glycine on MM in vivo. The unpaired t test was used to evaluate the difference between two different groups. Two-sided Fisher's exact tests were used to assess the associations between glycine abundance and clinical characteristics in MM patients, with a confidence coefficient (confidence interval, CI) of 95%. Results: Targeted metabolic assay of glycine in peripheral blood confirmed that glycine was significantly higher in MM patients than HD(HD vs. MM patients, 14000 vs. 15200, p=0.047). To explore the role of high glycine in MM progression, the associations between glycine abundance and clinical characteristics were investigated. We found that MM patients with high glycine had significantly higher plasma cells percentage(High glycine vs. Low glycine, 11.00% vs. 27.95, p=0.039) and lower hemoglobin concentration(High glycine vs. Low glycine, 96g/l vs. 77g/l, p=0.016). Moreover, high glycine was found to associate with bone damage(p=0.031). Additionally, colony formation and cell cycle assay results showed Glycine-free RPMI 1640 media inhibited MM cells proliferation. Furthermore, 5TMG1 MM mouse fed with glycine-deficiency fodder had slower progression as compared with 5TMG1 MM mouse fed with normal fodder(p=0.0007). These data suggested that exogenous glycine contributes to MM progression. To characterize how exogenous glycine is metabolized in MM cells, MM cell lines ARP1 and 5TGM1 were cultured in the presence of uniformly labeled 13C-glycine for 2, 4, and 6 hours, then the concentration of glycine metabolism related metabolites in conditional media and MM cells were tested by using LC-MS. As a result, 13C-glycine derived GSH was observed in ARP1 as well as 5TGM1, accounting for 37.2% and 52.7% of total GSH after 6 hours of culture, respectively, alternatively, the levels of 13C-GSH in both cell lines were up-regulated with the extension of culture time, indicating that exogenous glycine was involved in GSH synthesis in MM cells. Furthermore, addition of GSH(10 uM) to glycine-free RPMI 1640 media recover the proliferation ability of ARP1 and 5TGM1. Interestingly, betaine, a competitive similar of glycine, was found to suppress MM cell proliferation, and addition of GSH partially counteracted the effect of betaine on MM cells. Conclusion: These findings thus indicate that glycine promotes MM proliferation in vivo and in vitro, and GSH synthesis is the main metabolic pathway contributing to proliferation. Pharmacological blockage of glycine uptake and utilization shows therapeutic potential in MM treatment. Disclosures No relevant conflicts of interest to declare.

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The Role of PHF19 As a Promoter of Tumorigenicity and Therapeutic Target in Multiple Myeloma

Blood ◽

10.1182/blood-2019-130595 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 508-508

Author(s):

Carolina D. Schinke ◽

Pingping Qu ◽

Shmuel Yaccoby ◽

Valeriy V Lyzogubov ◽

Veronica MacLeod ◽

...

Keyword(s):

Cell Cycle ◽

Multiple Myeloma ◽

Candidate Gene ◽

Cell Lines ◽

Crucial Role ◽

Plasma Cells ◽

Total Therapy

Introduction - Multiple Myeloma (MM) is a hematologic malignancy characterized by clonal growth of differentiated plasma cells (PCs). Despite improvement in MM therapy, the disease remains mostly incurable and is characterized by recurrent relapses with development of resistant clones that eventually lead to patient death. The pathways that lead to resistant and aggressive MM are not fully understood highlighting the need to improve our understanding of MM biology to identify potential new pathways and therapeutical targets. PHD Finger Protein 19 (PHF19) is a regulator of Polycomb Repressive Complex 2 (PRC2), the sole methyltransferase complex capable of catalyzing H3K27me3 to induce and enforce gene repression. PRC2 employs enhancer of zeste homolog 1 and 2 (EZH1/EZH2) as enzymatic subunits to hypermethylate H3K27. While overexpression and gain of function mutations of EZH1/2 have been observed in many cancers the role of this particular pathway in MM remains poorly understood. In the present study, we report on PHF19 as a new candidate gene to play a potential crucial role in MM oncogenesis. Methods- Gene expression profiling (GEP; Affymetrix U133 Plus 2.0) was performed on 739 MM patients (from total therapy trials [TT] 3-5; low risk MM n=636, high risk MM n=103), 42 patients with monoclonal gammopathy of undetermined significance (MGUS), 73 smoldering MM patients, 42 patients with primary plasma cell leukemia and 34 healthy donors. Myeloma risk was determined by the GEP 70 signature as previously defined. To test the implications of functional PHF19 knock down (KD) we used TRIPZ inducible PHF19 shRNA vs. scrambled control (Dharmacon) in two MM cell lines (JJN3 and ARP1). Real time PCR as well as western blotting was used to confirm PHF19 KD as well as to elucidate the effect on H3K27me3 (Cell Signaling). Functional in vitro studies included proliferation (Promega), clonogenic assays (StemCell), cell cycle and apoptosis assays (both Invitrogen). In vivo studies were performed using SCID mice that were subjected to tail vain injection with PHF19 KD JJN3 cells (n=10) or scrambled shRNA control (n=10). Weekly ELISA (Bethyl) and in vivo imaging (Xenogen) were performed and survival was recorded. Results- GEP of the previously mentioned patient populations and healthy controls identified PHF19 (chr9q33.2) as a candidate gene that was consistently dysregulated in MM patients. Mean expression levels at different MM stages correlated with disease aggressiveness (ANOVA, p<0.0001), Figure 1. High expression of PHF19 (log2>10.46) at diagnosis correlated significantly with adverse clinical parameters, including ISS III, anemia and elevated LDH, as well as worse overall survival (5 yr OS = 29% for patients with high PHF19 expression vs 77% for patients with low PHF19 expression [log2<10.46], p< 0.0001). These results led us to test the implications of functional PHF19 KD using TRIPZ inducible PHF19 shRNA vs. scrambled control in the JJN3 and ARP1 MM cell lines. PHF19 KD led to a drastic reduction of H3K27me3 thereby resulting in significantly reduced proliferation via cell cycle arrest, while apoptosis was not substantially altered. Clonogenic assays showed a significant reduction in colony numbers and size of MM cells with PHF19 KD compared to the control (>75% reduction in both cell lines, p<0.05). Xenograft studies showed consistently less tumor burden in the mice injected with PHF19 KD cells compared to scrambled control, evident through ELISA testing for IgG Kappa (Median =180 mg/ml for scrambled control vs 80 mg/ml for PHF19 KD at week 8, p=0.07) and bioimaging (Median bioilumisence 2.1x108 p/s for scrambled control vs. 0.8x108 p/s for PHF19 KD at week 8, non-significant). Median OS in mice injected with PHF19 KD cell was substantially longer (66 days) compared to mice subjected to scrambled control cells (54 days), p=0.052. Conclusion- In summary we show that PHF19 is upregulated in malignant plasma cells of MM patients and that PHF19 expression levels increase with advanced MM stages. High PHF19 expression was a marker of adverse prognosis in our total therapy (TT 3-5) cohort. Most importantly, in-vitro and in-vivo functional studies showed that PHF19 has important biological functions in MM. These results suggest that epigenetic regulation through histone methylation, in particular, H3K27 trimethylation, plays a crucial role in MM and the affected downstream pathways should be further elucidated. Disclosures Boyle: Janssen: Honoraria, Other: Travel; Abbvie: Honoraria; Amgen: Honoraria, Other: travel; Takeda: Honoraria, Other: travel; Celgene Corporation: Honoraria, Other: Travel. van Rhee:Kite Pharma: Consultancy; Adicet Bio: Consultancy; Karyopharm Therapeutics: Consultancy; Takeda: Consultancy; Sanofi Genzyme: Consultancy; Castleman Disease Collaborative Network: Consultancy; EUSA: Consultancy. Walker:Celgene: Research Funding.

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CXCR4 Promotes the Tumorogenicity of Multiple Myeloma, Including Increased Motility, Clonogenicity, up-Regulation of VLA-4, Protection From Chemotherapy and Aggressive Tumor Development In Vivo

Blood ◽

10.1182/blood.v118.21.1801.1801 ◽

2011 ◽

Vol 118 (21) ◽

pp. 1801-1801

Author(s):

Katia Beider ◽

Amnon Peled ◽

Lola Weiss ◽

Merav Leiba ◽

Avichai Shimoni ◽

...

Keyword(s):

Multiple Myeloma ◽

Cell Lines ◽

Molecular Mechanisms ◽

Conflicts Of Interest ◽

Critical Role ◽

Tumor Development ◽

Soft Agar ◽

Induced Apoptosis

Abstract Abstract 1801 Background: Multiple myeloma (MM) is by large incurable neoplasm of plasma cells, characterized by accumulation in the bone marrow (BM), in close contact to cellular and extracellular matrix (ECM) components. Chemokine receptor CXCR4 is expressed by the majority of patients' MM cells. It promotes myeloma cell migration and homing to the BM compartment, supports the tumor cells survival and protects the myeloma cells from chemotherapy-induced apoptosis. Further investigation is required to define the specific molecular mechanisms regulated by the CXCR4/CXCL12 axis in MM. However, surface CXCR4 is commonly down-regulated in the MM cell lines. In order to overcome this limitation, the aim of the current study was to produce a reliable model for studying the functional role of high CXCR4 in MM by generating MM cell lines with stable expression of surface CXCR4. Results: To over-express CXCR4, we transduced CXCL12-expressing MM cell lines ARH77 and RPMI8226 with lentiviral vector and generated cell lines with high and stable levels of surface CXCR4. Enhanced CXCR4 expression significantly increased the in vitro survival and growth of the 2 MM cell lines in serum-deprivation conditions (p<0.01). Furthermore, elevated expression of surface CXCR4 prominently increased MM cells motility and promoted CXCL12-dependent transwell migration of the transduced MM cell lines. Highly CXCR4-expressing RPMI8226 and ARH77 cells demonstrated 40% migration in response to CXCL12 (50 ng/ml), versus only 0–5% migration of MM cells with low expression of surface CXCR4 (p<0.01). Furthermore, adhesion of MM cells to either ECM proteins or BMSCs localize the malignant PCs within the BM microenvironment, promote growth and survival of MM cells and play a critical role in myeloma bone disease and tumor invasion. In accordance, we observed induced adhesion of the transfected RPMI8226-CXCR4 cells to ECM components fibronectin and laminin and to BM fibroblasts. Moreover, we found that enhanced CXCR4 not only functionally activates, but rather significantly elevates the surface levels of VLA-4 integrin on the RPMI8226 cells. In addition, we found that CXCR4-expressing MM cells were less sensitive to melphalan- and bortezomib-induced apoptosis, when they were co-cultured with BM fibroblasts. Testing the molecular signaling pathways regulated by CXCR4, we found that elevated CXCR4 increased the basic level of pERK1/2 and pAKT in the MM cells, and promoted their prolonged activation in response to CXCL12 stimulation. Finally, the ability to produce colonies in the soft agar semi-solid culture reflects the tumorigenic capacity of cancer cells and cancer stem cells. Differentiated MM cells thus rarely produce colonies in soft agar. Here, we demonstrate that up regulation of CXCR4 promoted ARH77 and RPMI8226 colony formation, significantly increasing colonies number and size. Lastly, we determined the role of CXCR4 in MM tumor development in vivo. CXCR4-expressing ARH77 and RPMI8226 cells were subcutaneously injected into NOD/SCID mice. CXCR4-expressing cells, but not parental cell lines, produced detectable tumors already 10 days after the injection. Rapid tumor growth was further observed in both CXCR4-expressing cell lines. These findings indicate that CXCR4 provided aggressive phenotype and supported MM growth in vivo. Conclusions: Taken together, our findings clearly demonstrate the important pathophysiologic role of CXCR4 in MM development and progression. Furthermore, for the first time, we provide the evidence for CXCR4 oncogenic potential in MM, showing that CXCR4 promotes the clonogenic growth of MM cells. Our model may further serve to elucidate CXCR4-regulated molecular events potentially involved in the pathogenesis of MM, and strongly support targeting CXCR4 as therapeutic tool in MM. Disclosures: No relevant conflicts of interest to declare.

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Dual Targeting of -TORC1 and -TORC2 as a New Strategy In the Treatment of Multiple Myeloma

Blood ◽

10.1182/blood.v116.21.133.133 ◽

2010 ◽

Vol 116 (21) ◽

pp. 133-133 ◽

Cited By ~ 2

Author(s):

Patricia Maiso ◽

AbdelKareem Azab ◽

Yang Liu ◽

Yong Zhang ◽

Feda Azab ◽

...

Keyword(s):

Cell Cycle ◽

Multiple Myeloma ◽

Bone Marrow ◽

Board Of Directors ◽

Cell Lines ◽

Mechanism Of Action ◽

Plasma Cells ◽

Bone Marrow Microenvironment ◽

Advisory Committees

Abstract Abstract 133 Introduction: Mammalian target of rapamycin (mTOR) is a downstream serine/threonine kinase of the PI3K/Akt pathway that integrates signals from the tumor microenvironment such as cytokines and growth factors, nutrients and stresses to regulate multiple cellular processes, including translation, autophagy, metabolism, growth, motility and survival. Mechanistically, mTOR operates in two distinct multi-protein complexes, TORC1 and TORC2. Activation of TORC1 leads to the phosphorylation of p70S6 kinase and 4E-BP1, while activation of TORC2 regulates phosphorylation of Akt and other AGC kinases. In multiple myeloma (MM), PI3K/Akt plays an essential role enhancing cell growth and survival and is activated by the loss of the tumor suppressor gene PTEN and by the bone marrow microenvironment. Rapamycin analogues such as RAD001 and CCI-779 have been tested in clinical trials in MM. Their efficacy as single agents is modest, but when used in combination, they show higher responses. However, total inhibition of Akt and 4E-BP1 signaling requires inactivation of both complexes TORC1 and TORC2. Consequently, there is a need for novel inhibitors that can target mTOR in both signaling complexes. In this study we have evaluated the role of TORC1 and TORC2 in MM and the activity and mechanism of action of INK128, a novel, potent, selective and orally active small molecule TORC1/2 kinase inhibitor. Methods: Nine different MM cell lines and BM samples from MM patients were used in the study. The mechanism of action was investigated by MTT, Annexin V, cell cycle analysis, Western-blotting and siRNA assays. For the in vivo analyses, Luc+/GFP+ MM.1S cells (2 × 106/mouse) were injected into the tail vein of 30 SCID mice and tumor progression was detected by bioluminescence imaging. Nanofluidic proteomic immunoassays were performed in selected tumors. Results: To examine activation of the mTOR pathway in MM, we performed kinase activity assays and protein analyses of mTOR complexes and its downstream targets in nine MM cell lines. We found mTOR, Akt, pS6R and 4E-BP1 are constitutively activated in all cell lines tested independently of the status of Deptor, PTEN, and PI3K. All cell lines expressed either Raptor, Rictor or both; excepting H929 and U266LR7 which were negative for both of them. Moreover, primary plasma cells from several MM patients highly expressed pS6R while normal cells were negative for this protein. We found that INK128 and rapamycin effectively suppressed phosphorylation of p6SR, but only INK128 was able to decrease phosphorylation of 4E-BP1. We observed that INK128 fully suppressed cell viability in a dose and time dependent manner, but rapamycin reached a plateau in efficacy at ± 60%. The IC50 of INK128 was in the range of 7.5–30 nM in the eight cell lines tested. Similar results were observed in freshly isolated plasma cells from MM patients. Besides the induction of apoptosis and cell cycle arrest, INK128 was more potent than rapamycin to induce autophagy, and only INK128 was able to induce PARP and Caspases 3, 8 and 9 cleavage. In the bone marrow microenvironment context, INK128 inhibited the proliferation of MM cells and decreased the p4E-BP1 induction. Importantly, treatment with rapamycin under such conditions did not affect cell proliferation. INK128 also showed a significantly greater effect inhibiting cell adhesion to fibronectin OPM2 MM1S, BMSCs and HUVECs compared to rapamycin. These results were confirmed in vivo. Oral daily treatment of NK128 (1.0 mg/kg) decreased tumor growth and improved survival of mice implanted with MM1S. Conclusion: Dual inhibition of TORC1 and TORC2 represent a new and promising approach in the treatment of MM and its microenvironment. The ability of INK128 to inhibit both TORC1 and TORC2 strongly supports the potential use of this compound in MM patients. Disclosures: Anderson: Millennium Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Ghobrial:Celgene: Membership on an entity's Board of Directors or advisory committees; Millennium: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees.

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Identification of Tight Junction Protein (TJP)-1 As a Modulator of Sensitivity to Doxorubicin and Cisplatin in Models of Multiple Myeloma

Blood ◽

10.1182/blood.v120.21.3962.3962 ◽

2012 ◽

Vol 120 (21) ◽

pp. 3962-3962

Author(s):

Xing-Ding Zhang ◽

Robert Z. Orlowski ◽

Lin Yang

Keyword(s):

Multiple Myeloma ◽

Cell Lines ◽

Hela Cells ◽

Conflicts Of Interest ◽

Myeloma Cell ◽

Cancer Center ◽

In Vivo Models ◽

Junction Protein ◽

Rpmi 8226

Abstract Abstract 3962 Background: Therapeutic advances in multiple myeloma have improved the outcomes of patients with this malignant plasma cell disorder, but the disease course is still strongly influenced by both innate, or primary, as well as acquired, or secondary mechanisms of drug resistance. Identification and validation of genes that may mediate these phenotypes is therefore of importance, since they could be useful prognostic markers, and also potential targets to overcome the emergence of resistance, or possibly preclude its emergence altogether. Methods: To identify non-redundant determinants of chemoresistance, we designed a robust, high-throughput RNA interference (RNAi) screen targeting 9610 human genes. The screen involved retroviral-mediated transduction first of HeLa cervical carcinoma cells with either the RNAi library, or with non-targeting retrovirus particles. After infection, cells were selected with puromycin, and treated with different concentrations of doxorubicin and cisplatin. Doxorubicin (Dox) treatment led to 33 surviving colonies from the cells transduced with the shRNA library, cisplatin (Cis) treatment led produced 22 surviving colonies, while non-targeting retrovirus-infected cells failed to form colonies after treatment. Screening was performed to identify the shRNA target gene(s) in each colony, and genes that were identified in both Dox- and Cis-treated HeLa cells, and that were expressed in myeloma cells, were selected for further study. These studies were supported by the M. D. Anderson Cancer Center SPORE in Multiple Myeloma. Results: TJP1 (zona occludens (ZO)-1) was identified as one gene whose knockdown promoted survival in Dox- and Cis-treated HeLa cells, and which was expressed in myeloma cell lines and in primary plasma cells. To further examine its potential role in myeloma chemosensitivity, we performed mRNA and protein expression profiling in a panel of 11 cell lines and observed that TJP1 expression was silenced in 3 cell lines (ARP-1, INA-6, and MOLP-8), while it was moderately to highly expressed in 7 cell lines (including RPMI 8226, MM1.S, and U266). Comparing TJP1-positive MM1.S cells to TJP1-null MOLP-8 cells, the latter displayed a significantly higher median inhibitory concentration to Dox and Cis. Knockdown of TJP1 in RPMI 8226 and U266 cells, which produced a >75% target suppression, was sufficient to reduce the proportion of apoptotic cells in the sub-G1 fraction after treatment with Dox or Cis compared to control cells. Conversely, MOLP-8 cells transfected with human TJP1 cDNA exhibited an increase in the sub-G1 population in response to Dox and Cis treatment compared to vector controls. Conclusion: Taken together, these studies support the hypothesis that TJP1 expression mediates myeloma cell resistance to the DNA damaging agents doxorubicin and cisplatin. Further studies are underway to determine the mechanism by which TJP1 influences chemosensitivity, and to validate its impact using in vivo models. Disclosures: No relevant conflicts of interest to declare.

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Anti-CD138-IFNα Fusion Proteins Are Effective in Treating Multiple Myeloma

Blood ◽

10.1182/blood.v120.21.939.939 ◽

2012 ◽

Vol 120 (21) ◽

pp. 939-939

Author(s):

Esther Yoo ◽

Alex Vasuthasawat ◽

Danh Tran ◽

Alan Lichtenstein ◽

Sherie Morrison

Keyword(s):

Multiple Myeloma ◽

Fusion Protein ◽

Cell Lines ◽

Dna Content ◽

Fusion Proteins ◽

Conflicts Of Interest ◽

Myeloma Cell ◽

Inhibition Of Proliferation ◽

Discontinue Therapy

Abstract Abstract 939 Although IFNα has shown some efficacy in the treatment of multiple myeloma (MM), this efficacy has been limited in large part because systemic toxicity makes it difficult if not impossible to reach therapeutically effective doses at the site of the tumor. The short half-life of IFN also makes it difficult to sustain high levels during treatment, and because of the side effects, the patients often discontinue therapy. To address these issues, we have genetically fused IFNα2 to a chimeric IgG1 antibody specific for the antigen CD138 expressed on the surface of MM cells, yielding anti-CD138-IFNα. We have also produced a fusion protein (anti-CD138-mutIFNα) using a mutant IFNα that binds the IFN receptor (IFNAR) more tightly. The fusion proteins continued to bind CD138 and retained IFN activity and showed anti-proliferative activity against a broad panel of myeloma cell lines (HMCL) representing MM with different characteristic. To investigate the events responsible for the inhibition of proliferation, 8226/S, ANBL-6, MM1-144, H929, OCI-My5 and U266 cells were incubated with 500 pM anti-CD138-IFNα for 72 h and their DNA content analyzed by FLOW cytometry following permeabilization and staining with PI. The different cell lines exhibited different responses. All of the cell lines except OCI-My5 underwent apoptosis. For 8226/S, OCI-My5 and U266 there was little change in DNA content following treatment. ANBL-6 showed a slight increase in the number of cells in S. However, MM1-144 and H929 showed a marked accumulation in G2 with H929 also showing accumulation of cells with sub-G0content of DNA. Therefore, there is heterogeneity in the response of different HMCL to treatment with targeted IFNα2. For many but not all of the cell lines, anti-CD138-mutIFNα was more effective than anti-CD138-IFNα in inhibiting proliferation and causing DNA fragmentation. Anti-CD138-mutIFNα was more effective than anti-CD138-IFNα in inducing senescence-associated β-galactosidase and STAT1 activation in OCI-My5 cells. Treatment with anti-CD138-IFNα or anti-CD138-mutIFNα resulted in a decrease in the amount of IRF4 present in U266, suggesting that this may be responsible for the efficacy of the fusion proteins in this cell line. Treatment of the other cell lines did not alter the level of IRF4 present, but anti-CD138-IFNα and anti-CD138-mutIFNα treatment caused a decrease in the amount of ppRB present in 8226/S, OCI-My5 and MM1-144, and to a lesser extent in H929. To determine the in vivo efficacy of fusion protein treatment, SCID mice were injected subcutaneously with OCI-My5 cells and treated intravenously on days 14, 16 and 18 with 100 μg of the indicated proteins and monitored for tumor growth (Figure 1). Mice were sacrificed when tumors exceeded 1.5 cm in diameter. Treatment with anti-CD138-IFNα provided some protection (p ≤ 0.0001 compared to PBS). However, treatment with anti-CD138-mutIFNα was even more effective (p = 0.0004 compared to anti-CD138-IFNα). Anti-CD138-mutIFNα was also found to be more effective than anti-CD138-IFNα against primary MM cells. Patients with active myeloma were biopsied while off therapy and the marrow cells isolated by a negative antibody selection to >95% purity. After 72 h incubation with 25 nM of protein, anti-CD138 was found to have little effect. In contrast treatment with anti-CD138-IFNα caused a decrease in viability with anti-CD138-mutIFNα treatment leading to an even greater decrease in cell viability. Following 72 h of treatment, 25 nM of anti-CD138-mutIFNα was found to have more potent cytoreductive effects than 100 nM of anti-CD138-IFNα. Disclosures: No relevant conflicts of interest to declare.

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ANKHD1 Silencing Reduces In Vitro Clonogenicity and In Vivo Tumorogenicity Of Multiple Myeloma Cells

Blood ◽

10.1182/blood.v122.21.3168.3168 ◽

2013 ◽

Vol 122 (21) ◽

pp. 3168-3168

Author(s):

Anamika Dhyani ◽

João Agostinho Machado-Neto ◽

Patricia Favaro ◽

Sara Teresinha Olalla Saad

Keyword(s):

Cell Cycle ◽

Gene Therapy ◽

Multiple Myeloma ◽

Cell Lines ◽

Tumor Size ◽

Control Group ◽

Mice Model ◽

And Migration

Abstract Introduction ANKHD1 is a multiple ankyrin repeats containing protein, highly expressed in cancers, such as acute leukemia. Earlier studies showed that ANKHD1 is highly expressed and plays important role in proliferation and cell cycle progression of multiple myeloma (MM) cells. It was also observed that ANKHD1 downregulation modulates cell cycle gene expression and upregulates p21 irresepective of TP53 mutational status of MM cell lines. Objective The present study aimed to study the effect ofANKHD1 silencing on MM growth both in vitro (clonogenicity, migration) and in vivo (xenograft tumor mice model). The purpose was to investigate the feasibility of ANKHD1 gene therapy for MM. Methods In the present study, ANKHD1 expression was silenced using short hairpin RNA (shRNA)-lentiviral delivery vector in MM cell lines (U266 and MM1S). For control MM cells were tranduced by lentiviral shRNA against LacZ. Downregulation of ANKHD1 expression was confirmed by qPCR and Western blot. Colony formation capacity and migration of control and ANKHD1 silenced MM cells was determined by methylcellulose and transwell migration assays, respectively. For in vivo MM growth, NOD-SCID mice were divided in two groups injected with control and ANKHD1 silenced cells, separately. Mice were observed daily for tumor growth. Once the tumor size reached 1 mm3, mice in both groups were sacrificed and tumor was excised to measure tumor volume and weight. Results Corroborating the results obtained in our earlier studies, in the present study also inhibition of ANKHD1 expression suppressed growth of MM cells in vitro. MM cell lines tranduced with ANKHD1 shRNA showed significantly low number of colonies ten days after plating in methylcellulose medium as compared to control (p<0.05). Similarly, in transwell migration assay, cell lines transduced with ANKHD1 showed significantly less migration as in response to 10% FBS at lower chamber as compared to control group (p<0.05) in both the cell lines analyzed. Further in xenograft MM mice model, the growth of tumor was visibly suppressed in mice injected with ANKHD1 silenced cells compared to control group. There was significant difference in tumor size (volume) between these 2 groups (P< 0.006). The tumor weight of the inhibition group was 0.71 ±0.2 g, significantly lighter than those of the control group (1.211 ± 0.5 g, P =0.02) Conclusion Our data indicates ANKHD1 downregulation significantly inhibits colony-forming ability and migration of both glucocorticoid resistant (U266) and sensitive (MM1S) MM cells. Further, gene silencing of ANKHD1 also resulted in reduced in vivo tumor growth in NOD/SCID mice. Collectively, the result obtained indicates that ANKHD1 may be a target for gene therapy in MM. Disclosures: No relevant conflicts of interest to declare.

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Constitutive and Immunoproteasome Inhibitors Increase IκB and Decrease NF-κB Expression In Dendritic Cell

Blood ◽

10.1182/blood.v122.21.3493.3493 ◽

2013 ◽

Vol 122 (21) ◽

pp. 3493-3493

Author(s):

Ahmad-Samer Samer Al-Homsi ◽

Zhongbin Lai ◽

Tara Sabrina Roy ◽

Niholas Kouttab

Keyword(s):

Multiple Myeloma ◽

T Cell ◽

Cell Lines ◽

Mechanism Of Action ◽

Peripheral Blood ◽

Research Funding ◽

Myeloma Cell ◽

Multiple Myeloma Cell

Abstract Introduction Constitutive and immunoproteasome inhibitors (C&IPI) were thought to suppress nuclear factor-κB (NF-κB) pathway by preventing IκB degradation, which prevents NF-κB translocation into the nucleus. This mechanism of action has since been questioned by a number of studies. First, bortezomib promoted constitutive NF-κB activity in endothelial cell carcinoma. Second, NF-κB constitutive activity was resistant to bortezomib in multiple myeloma cell lines. Third, bortezomib increased IκB mRNA but post-transcriptionally downregulated IκB in normal cells and in multiple myeloma cell lines resulting in induced canonical NF-κB activation. Lastly, bortezomib increased nuclear levels of IκB as opposed to lowering cytoplasmic levels in cutaneous T cell lymphoma cell line suggesting that nuclear translocation of IκB was possibly responsible for NF-κB inhibition. The inhibitory activity of C&IPI on dendritic cells (DC) is of interest in the prevention of graft versus host disease (GvHD). It has been shown that different C&IPI impede DC maturation and T cell priming both in vitro and in vivo. Herein we sought to understand the mechanism of action of proteasome and immunoproteasome inhibitors on DC and to test their effect on IκB and NF-IκB expression. Materials and Methods We first performed RT PCR on lysates of DC obtained from the peripheral blood of 7 patients who received post-transplant cyclophosphamide and bortezomib as prevention of GvHD on a phase I clinical trial. Patients received allogeneic transplantation from matched-related or unrelated donors. Patients received no other immunosuppressive therapy except for rabbit anti-thymocyte globulin for those receiving graft from unrelated donor. Steroids were not allowed on the study. Samples were obtained on days +1, +4, and +7. The results were analyzed in comparison to samples obtained on day 0 before stem cell infusion. We then performed the same experiment on lysates of DC obtained from the peripheral blood of healthy volunteer donors. DC were untreated or incubated with bortezomib (10 nM for 4 h), carfilzomib (30 nM for 1 h), oprozomib (100 nM and 300 nM for 4 h), ONX 0914 (200 nM for 1 h), PR-825 (125 nM for 1 h), or PR-924 (1000 nM for 1 h). The drug concentration and duration of exposure were chosen based on the IC50 on proteasome activity and to reproduce in vivo conditions. We also performed IκB western blot on DC isolated from peripheral blood of healthy volunteers, untreated or incubated with bortezomib (10 nM for 4 h) or oprozomib (300 nM for 4 h). Each experiment was performed at least in triplicate. Results We found that the combination of cyclophosphamide and bortezomib significantly and progressively increased IκB mRNA while decreasing NF-κB mRNA in DC studied ex vivo. We also found that all studied C&IPI increased IκB mRNA to a variable degree while only oprozomib (300 nM) decreased NF-κB mRNA in DC in vitro. Finally, both bortezomib and oprozomib increased IκB protein level in DC in vitro (figure). Conclusion Our data suggest that C&IPI increase IκB expression in DC. As opposed to the previously reported data in other cell types, the effect is not associated with post-transcriptional downregulation. Cyclophosphamide and bortezomib also decrease NF-κB expression in DC in vivo while only oprozomib had the same effect in vitro. The effect of C&IPI on IκB and NF-κB expression may represent a new mechanism of action and suggests their effect may be cell-type dependent. Disclosures: Al-Homsi: Millennium Pharmaceuticals: Research Funding. Off Label Use: The use of cyclophosphamide and bortezomib for GvHD prevention. Lai:Millennium Pharmaceuticals: Research Funding.

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The BTK Inhibitor Ibrutinib Blocks SDF1/CXCR4 Mediated Migration of Acute Myeloid Leukemia Cells

Blood ◽

10.1182/blood.v124.21.915.915 ◽

2014 ◽

Vol 124 (21) ◽

pp. 915-915

Author(s):

Stuart A Rushworth ◽

Lyubov Zaitseva ◽

Megan Y Murray ◽

Matthew J Lawes ◽

David J MacEwan ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Cell Lines ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Lymphocytic Leukemia ◽

Cell Trafficking ◽

Acute Myeloid

Abstract Introduction Despite recent significant progress in the understanding of the biology of acute myeloid leukemia (AML) the clinical outcomes for the majority of patients diagnosed with AML presently remain poor. Consequently, there is an urgent need to identify pharmacological strategies in AML, which are not only effective but can be tolerated by the older, less well patient. Recently our group and others have shown that there is high Bruton’s Tyrosine Kinase (BTK) phosphorylation and RNA expression in AML. Moreover, our recent study described for the first time that ibrutinib and BTK-targeted RNA interference reduced factor-induced proliferation of both AML cell lines and primary AML blasts, as well as reducing AML blast adhesion to bone marrow stromal cells. Inhibition of BTK has been shown to regulate chronic lymphocytic leukemia, mantle cell lymphoma and multiple myeloma cell migration by inhibiting SDF1 (stromal derived factor 1) induced CXCR4 regulated cell trafficking. Here we report that in human AML ibrutinib in addition functions in a similar way to inhibit SDF1/CXCR4-mediated AML migration at concentrations achievable in vivo. Methods To investigate the role of BTK in regulating AML migration we used both pharmacological inhibitor ibrutinib and genetic knockdown using a lentivirus mediated BTK targeted miRNA in primary AML blasts and AML cell lines. We examined migration of AML blasts and AML cells to SDF-1 using Transwell permeable plates with 8.0µM pores. Western blotting was used to examine the role of SDF-1 in regulating BTK, AKT and MAPK activation in primary AML blasts. Results We initially examined the expression of CXCR4 in human AML cell lines and found that 4/4 cell lines were positive for CXCR4 expression. Next we examined the effects of ibrutinib on the migration of the AML cell lines U937, MV4-11, HL60 and THP-1 in response to SDF1. We found that ibrutinib can inhibit the migration of all AML cell lines tested. We tested the in-vitro activity of ibrutinib on SDF-1 induced migration in a spectrum of primary AML blasts from a wide age spectrum of adult patients and across a range of WHO AML subclasses and found that ibrutinib significantly inhibits primary AML blast migration (n=12). Next we found that ibrutinib can inhibit SDF-1 induced BTK phosphorylation and downstream MAPK and AKT signalling in primary AML blast. Finally to eliminate the problems associated with off target ibrutinib activity we evaluated migration of AML cells lines using genetic inhibition of BTK. The introduction of BTK-specific miRNA dramatically inhibited the expression of BTK in THP-1 and HL60 and reduced SDF1 mediated migration confirming that BTK is involved in regulating AML migration in response to SDF1. Conclusions 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. Disclosures No relevant conflicts of interest to declare.

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Overexpression of PFKFB3 Promotes Cell Glycolysis and Proliferation in Renal Cell Carcinoma

10.21203/rs.3.rs-255023/v1 ◽

2021 ◽

Author(s):

Jun Li ◽

Shiqiang Zhang ◽

Dingzhun Liao ◽

Qian Zhang ◽

Chujie Chen ◽

...

Keyword(s):

Cell Cycle ◽

Renal Cell Carcinoma ◽

Tumor Growth ◽

Cell Carcinoma ◽

Cell Lines ◽

Renal Cell ◽

Aerobic Glycolysis ◽

Xenograft Model

Abstract Background: Cancer cells prefer aerobic glycolysis to increase their biomass and sustain uncontrolled proliferation. As a key glycolytic activator, phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) has been implicated in the progression of multiple types of tumors. However, the specific function and clinical significance of PFKFB3 in renal cell carcinoma (RCC) remain unclear. In the present study, we explored the role of PFKFB3 in RCC.Methods: We analyzed the expression of PFKFB3 in clear cell renal cell carcinoma (ccRCC) tissues and its relationship with clinical characteristics of ccRCC. Real-time PCR and Western blot analysis were used to detect PFKFB3 expression levels in different RCC cell lines. Furthermore, we determined the glycolytic activity by glucose uptake, lactate secretion assay and ECAR analysis. CCK-8 assay, clone formation assay, flow cytometry and EdU assay were performed to monitor cancer cell proliferation and cell cycle distribution. In addition, nude mice xenograft model was used to investigate the role of PFKFB3 in tumor growth in vivo.Results: In this study, we found that PFKFB3 was significantly up-regulated in RCC tissues and cell lines compared with normal control. Overexpression of PFKFB3 was positively associated with advanced TNM stage and could predict poor prognosis of ccRCC patients. Furthermore, knockdown of PFKFB3 suppresses cell glycolysis, proliferation and cell cycle G1/S transition in RCC cells. Importantly, in vivo experiments confirmed that PFKFB3 knockdown delayed tumor growth derived from the ACHN cell line.Conclusion: Our results suggest that PFKFB3 plays an important role in the progression of RCC via mediating glycolysis and proliferation, and provides a potential therapeutic target for RCC.

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Xenograft Models of Multiple Myeloma Reveal That PU.1 Serves As a Tumor Suppressor for Multiple Myeloma

Blood ◽

10.1182/blood.v124.21.2047.2047 ◽

2014 ◽

Vol 124 (21) ◽

pp. 2047-2047

Author(s):

Nao Nishimura ◽

Shinya Endo ◽

Niina Ueno ◽

Shikiko Ueno ◽

Hiromichi Yuki ◽

...

Keyword(s):

Multiple Myeloma ◽

Cell Growth ◽

Tumor Suppressor ◽

Cell Lines ◽

Conflicts Of Interest ◽

Myeloma Cell ◽

Suppressor Activity ◽

Enhancer Region ◽

Tumor Suppressor Activity

Abstract PU.1 is an essential transcription factor for hematopoiesis and important for differentiation of both myeloid and lymphoid lineages. In mice conditionally knocked-out of 3.4 kb length of the enhancer region located in14 kb 5’ upstream of the PU.1 gene (URE), PU.1 is down-regulated in myeloid cells and B cells by 20% of that of wild type, and such mice develop acute myeloid leukemia and CLL-like diseases. These data strongly suggest that PU.1 has tumor suppressor activity in hematopoietic cells. We previously reported that human PU.1 is down-regulated in the majority of myeloma cell lines through the methylation of the promoter and the 17 kb upstream enhancer region (URE) of the PU.1 gene that is homologous to that in 14 kb 5’ upstream of the murine PU.1 gene. Conditionally expressed PU.1 with tet-off system induced cell growth arrest and apoptosis in two myeloma cell lines, KMS12PE and U266, suggesting that the down-regulation of PU.1 is necessary for myeloma cell growth. We have also reported that PU.1 is expressed in normal plasma cells and in contrast, PU.1 is down-regulated in primary myeloma cells from a subset of myeloma patients, who appear to have poor prognosis. In the present study, to test whether PU.1 has tumor suppressor activity in vivo, we generated xenograft mouse models. 0.6 - 1 x 107 KMS12PE cells were subcutaneously injected in 16 immunodeficient mice (Rag2-/- Jak3-/- bulb/c). The mice were then administered doxycycline through drinking water. Half of the mice (N=8) stopped taking doxycycline when the tumor sizes reached 1 cm in diameter, whereas the other half (N=8) kept taking doxycycline. Although the tumors in the mice taking doxycycline continued to grow, the tumor growth in the mice not taking doxycycline significantly slowed down. Flow cytometry analysis of the tumors in the mice that stopped taking doxycycline revealed that the cells from the tumor had completely lost PU.1 expression. Moreover, when U266 cells conditionally expressing PU.1 were subcutaneously injected to another 10 mice and the same experiment was conducted, although the tumors in the mice taking doxycycline (N=5) kept growing, the tumors in the mice not taking doxycycline (N=5), did not grow any further. The present data suggest that PU.1 serves as a tumor a suppressor in the multiple myeloma cell lines as examined in vivo. Disclosures No relevant conflicts of interest to declare.

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