Growth Inhibition and Synergistic Induction of Apoptosis By Synthetic Mir-125b-5p Mimics and Myc-Targeting Agents in Human Myeloma Cell Lines

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3019-3019
Author(s):  
Lavinia Biamonte ◽  
Cinzia Federico ◽  
Eugenio Morelli ◽  
Emanuela Leone ◽  
Maria Eugenia Gallo Cantafio ◽  
...  
Keyword(s):  
Cell Lines ◽  
Conflicts Of Interest ◽  
Therapeutic Potential ◽  
Apoptotic Cell ◽  
Synergistic Effects ◽  
Annexin V ◽  
Transcriptional Level ◽  
Suppressor Activity

Abstract MicroRNAs (miRNAs), short non-coding RNAs which tune gene expression at post-transcriptional level, are recently emerging as key players in pathogenesis, progression and drug-resistance of multiple myeloma (MM). In this disease, they can act either with tumor-promoting or tumor-suppressing functions, depending on the nature of target mRNAs. Nowadays, effective strategies are available both to replace or to inhibit the expression of deregulated miRNAs, thus prompting the design of miRNA-based therapeutic strategies. We have recently demonstrated that miR-125b has tumor suppressor activity in MM and that enforced expression of synthetic miR-125b-5p mimics induces significant anti-MM activity in vitro and in vivo by targeting cell addiction to IRF4/cMyc pro-survival signaling. Moreover, we uncovered a functional feedback loop between cMyc and miR-125b in MM cells, whereas cMyc directly suppresses miR-125b transcription which, in turn, negatively regulates cMyc expression by targeting IRF4 mRNA. In the present study, we investigated the therapeutic potential of synthetic miR-125b-5p mimics combined with cMyc targeting agents, including the 10058-F4 small molecule inhibitor of cMyc-Max heterodimerization and the BET-bromodomain inhibitor JQ1, which is reported to inhibit cMyc transcription. At this aim, 3 MM cell lines (NCI-H929, SK-MM-1 and RPMI-8226) transfected with either miR-125b-5p mimics or scrambled oligonucleotides (miR-NC) were exposed to 10058-F4 (ranging from 10 to 100 μM) or JQ1 (ranging from 0,1 to 2μM) or DMSO. Effects on cell proliferation were then evaluated by CCK-8 assay at 24h, 48h and 72h time points, while the occurrence of apoptotic cell death was assessed by Annexin V flow-cytometry assay. Importantly, we found that enforced expression of miR-125b-5p mimics significantly and synergistically (synergistic index, SI >1) increases growth-inhibitory and pro-apoptotic activities of both 10058-F4 and JQ1. Similar results were observed in SK-MM-1 cells co-transfected with miR-125b-5p and cMyc siRNAs, while cMyc-defective U266 cells were not sensitized to either 10058-F4 nor JQ1 upon transfection with miR-125b-5p mimics. Furthermore, combinatorial treatments with JQ1 and miR-125b-5p mimics resulted in a stronger downregulation of cMyc protein, as compared to single molecules alone. Indeed, these results confirmed that impairment of cMyc activity/expression mediates the anti-MM synergistic effects between 10058-F4 or JQ1 and overexpression of miR-125b-5p by synthetic mimics. In conclusion, our data demonstrate a cMyc-mediated synergistic anti-MM activity of synthetic miR-125b-5p mimics with 10058-F4 or JQ1 cMyc targeting agents, providing the rationale for a more advanced preclinical investigations for the design of early clinical trials. Disclosures No relevant conflicts of interest to declare.

scholarly journals In Vitro Investigation of the Cytotoxic Activity of Emodin 35 Derivative on Multiple Myeloma Cell Lines

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jing Zheng ◽  
Yingyu Chen ◽  
Zhihong Zheng ◽  
Yanxin Chen ◽  
Yujuan Chai ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Signaling Pathway ◽  
Cell Lines ◽  
Synergistic Effects ◽  
Annexin V ◽  
Myeloma Cell ◽  
In Vitro Investigation ◽  
Cellular Apoptosis

Background. Bortezomib is used for treating multiple myeloma (MM); however, it has considerable adverse effects. Emodin has been reported to exhibit inhibitory effects on MM cell lines. We investigated the efficacy of emodin 35 (E35), an emodin derivative, using U266 and MM1s cell lines in treating MM and the efficacy of combining bortezomib and E35. Methods. MTT assays were used to observe the effects of E35 on MM cell growth. The effects on cellular apoptosis were then observed using Annexin V/propidium iodide (PI) staining assay. The expression of apoptosis-related genes, including the caspase family, was examined. The efficacy of combining bortezomib and E35 was investigated by examining the expression of the Akt/mTOR/4EBP1 signaling pathway-related proteins. Results. We report that E35 inhibited the growth of U266 and MM1s cells by inducing cellular apoptosis. Moreover, E35 downregulated the expression of apoptosis-related genes and suppressed the phosphorylation of Akt/mTOR/4EBP1 signaling pathway-related genes, thus exhibiting synergistic effects with bortezomib. All observed effects were dose-dependent. Conclusion. The results showed that E35 exhibited cytotoxic effects in MM cell lines in protein levels. Thus, E35, particularly in combination with bortezomib, may be considered as a promising treatment for MM; however, this requires further investigation in vivo.

Chemotherapy-Induced CXCR4 Modulation Predicts the In Vivo Efficacy of Plerixafor As a Chemosensitizer in Acute Leukemia

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1410-1410
Author(s):  
Edward Allan R. Sison ◽  
Daniel Magoon ◽  
Li Li ◽  
Rachel E. Rau ◽  
Colleen E. Annesley ◽  
...  
Keyword(s):  
High Risk ◽  
Cell Lines ◽  
Conflicts Of Interest ◽  
Leukemia Cell ◽  
Xenograft Model ◽  
Annexin V ◽  
Cxcr4 Expression ◽  
Pediatric Leukemia

Abstract Abstract 1410 Background: Activation of CXCR4 by the chemokine SDF-1 (CXCL12) results in the migration of leukemia cells to marrow niches that may contribute to chemoresistance and relapse. We previously showed that in vitro chemotherapy (chemo) treatment modulates CXCR4 expression in leukemia cell lines and primary pediatric AML samples, and that chemo-induced increases in surface CXCR4 (s-CXCR4) results in increased chemotaxis toward an SDF-1 gradient and decreased chemo-induced apoptosis when co-cultured with human marrow stroma feeder layers. We hypothesized that 1) CXCR4 inhibition by plerixafor (P) would sensitize leukemias to chemo through the interruption of leukemia-stromal cell signaling and 2) the degree of chemo-induced s-CXCR4 upregulation would be a predictive biomarker of the efficacy of P as a chemosensitizer. Because B-precursor ALL are known to highly express CXCR4, we tested these hypotheses in vitro using ALL cell lines and in vivo using a xenograft model of a high-risk pediatric leukemia, infant ALL. In Vitro Methods/Results: ALL cell lines were pretreated for 72 hours with araC (A), dauno, vcr, and vehicle control (C). Chemo pretreatment induced upregulation of s-CXCR4 compared to C. Viable cells were then isolated using Ficoll and plated off stroma (O), on stroma (S), or pretreated with P for 30 minutes prior to plating on stroma (P+S). Cells were then treated for an additional 72 hours with full dose ranges of chemo. Apoptosis was measured with Annexin V/7-AAD, and IC50 was calculated. Overall, IC50 values were highest in S, followed by P+S, then O, demonstrating that upregulation of s-CXCR4 leads to stromal protection, and that stromal protection is diminished by treatment with P. Cells with higher levels of s-CXCR4 upregulation had greater differences between S IC50 and O IC50, compared to cells with lower s-CXCR4 upregulation, suggesting that the degree of s-CXCR4 upregulation is predictive of the degree of stromal protection. Cells with higher s-CXCR4 upregulation also had greater differences between S IC50 and P+S IC50, suggesting that P diminishes stromal protection more effectively in leukemias that highly upregulate s-CXCR4 in response to chemo. Xenograft Methods/Results: Infant ALL patient samples were transplanted into sublethally irradiated NOG mice. After 3 weeks, we treated cohorts (n=5) with single doses of P, A, P followed by A 4 hours later (P+A), or C. We dosed A below the maximal tolerated dose (MTD) to facilitate assessment of P+A synergy. Mice were sacrificed 4 weeks post treatment and cells were isolated from bone marrow (BM), spleen, liver, and peripheral blood (PB) and analyzed by FACS. Leukemic blasts were defined as human CD19+ and CD45+. S-CXCR4 MFI was measured in the blast population. Overall, leukemic burden was similar in C, A, and P, consistent with conservative dosing of A and minimal direct anti-leukemic effect of P. A resulted in increased blasts in spleen and liver compared to C, possibly due to higher levels of s-CXCR4, while P resulted in increased blasts in liver, possibly due to mobilization of blasts. The key finding was that P+A resulted in decreased blasts in BM, spleen, liver, and PB, demonstrating a synergistic effect between P and A. Interestingly, P+A led to a higher reduction in blasts in a sample with A-induced s-CXCR4 upregulation, compared to a sample that did not upregulate s-CXCR4 in response to A. In all treatment cohorts, s-CXCR4 expression was highest in PB blasts, followed by liver, and BM/spleen. Conclusions: Chemo-induced s-CXCR4 upregulation confers stromal-mediated chemoprotection in vitro that can be reversed by P. In vivo, P is an effective chemosensitizer. S-CXCR4 expression is increased in blasts located outside the BM, suggesting that blasts migrating from BM into PB upregulate s-CXCR4 as they home to new niches. Extramedullary disease may develop as a result of chemo-induced upregulation of s-CXCR4 or through mobilization of blasts by P alone. Importantly, P+A resulted in decreased leukemic burden in our infant ALL xenografts, suggesting that chemo-induced increases in s-CXCR4 and P-induced blast mobilization can be overcome. Finally, the efficacy of P as a chemosensitizer was predicted by the degree of chemo-induced s-CXCR4 upregulation, identifying a biomarker with the potential to identify optimal patients for CXCR4 inhibition. P in combination with chemo may thus prove useful in the treatment of high-risk pediatric ALL. Disclosures: No relevant conflicts of interest to declare.

scholarly journals In Vitro Investigation of The Cytotoxic Activity of E35 on Multiple Myeloma Cell Lines

2020 ◽  
Author(s):  
Jing Zheng ◽  
Yingyu Chen ◽  
Zhihong Zheng ◽  
Yanxin Chen ◽  
Yujuan Chai ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Signaling Pathway ◽  
Cell Lines ◽  
Synergistic Effects ◽  
Annexin V ◽  
Myeloma Cell ◽  
In Vitro Investigation ◽  
Cellular Apoptosis

Abstract Background: Bortezomib is used for the treatment of multiple myeloma (MM); however, it has significant adverse effects. Emodin has been reported to exhibit inhibitory effects on MM cell lines. Here, we investigated the efficacy of E35, an emodin derivative, using U266 and MM1s cell lines in the treatment of MM and the efficacy of the combination of bortezomib and E35. Methods: MTT assays were used to observe the effects of E35 on MM cell growth. The effects on cellular apoptosis were observed using the Annexin V/propidium iodide (PI) staining assay. The expression of apoptosis-related genes, including the caspase family, was also examined. The efficacy of the combination of bortezomib and E35 was investigated by examining the expression of the Akt/mTOR/4EBP1 signaling pathway-related proteins. Results: We found that E35 inhibited the growth of the U266 and MM1s cells by inducing cellular apoptosis. E35 also downregulated the expression of the apoptosis-related genes and suppressed the phosphorylation of the Akt/mTOR/4EBP1 signaling pathway-related genes, exhibiting synergistic effects with bortezomib. All the observed effects were dose-dependent. Conclusion: The results of this study showed that E35 exhibited cytotoxic effects in MM cell lines. Thus, E35, especially in combination with bortezomib, may be considered as a promising treatment for MM. However, this requires further investigation in vivo.

P13.08 Novel Thioridazine derivates: Antiproliferative and apoptosis-inducing activity on glioblastoma cells in vitro

2021 ◽  
Vol 23 (Supplement_2) ◽  
pp. ii34-ii34
Author(s):  
S G Schwab ◽  
K Sarnow ◽  
E Alme ◽  
R Goldbrunner ◽  
H Bjørsvik ◽  
...  
Keyword(s):  
Imaging System ◽  
Therapeutic Potential ◽  
Flow Cytometric Analysis ◽  
Annexin V ◽  
Therapeutic Effects ◽  
Cell Viability Assay ◽  
Selective Cytotoxicity ◽  
Viability Assay

Abstract BACKGROUND Although withdrawn from the market due to cardiotoxicity, we have shown that the antipsychotic drug Thioridazine shows chemosensitizing effects in combination with Temozolomide (TMZ) for the treatment of glioblastoma multiforme (GBM). Based on our prior observations, the aim of the presented project was through medicinal chemistry, to design and synthesize new compounds based on Thioridazines tricyclic structure, and to determine their therapeutic potential. MATERIAL AND METHODS Fourteen compounds were synthesized where variations were made within the tricyclic side chains. The newly synthesized compounds were screened for therapeutic efficacy with or without TMZ using a WST-1 cell viability assay as well as a real-time imaging system (IncuCyte). Tests were performed on both monolayer cell cultures, as well as on glioma stem cell spheroids (GSC). The therapeutic effects were also studied on human astrocytes (NHA) as well as on rat brain organoids (BO). Annexin V/propidium iodide (PI) double staining followed by flow cytometric analysis was performed after 48 hours of treatment. RESULTS Following an extensive screening, we identified two novel compounds (EA01 and EA02) that at concentrations of 4 and 9.5 µM showed a strong cytotoxicity on GBM cell lines (U-87 MG p<0,0001, U251 p<0,0001, LN18 p=0,0004) as well as on glioma stem cells (GSC) (P3 p<0,0001) compared to NHA and BOs respectively. Also, when BOs were confronted with GSC spheres in an invasion assay, a selective cytotoxicity was observed in the GSCs. Mechanistically, we show that both compounds induce apoptosis in the GBM cells. Moreover, intravenous delivery of increasing concentrations of EA01 and EA02 revealed no toxicity in animals at concentrations up to 21 mg/kg. CONCLUSION We have developed two new tricyclic therapeutic compounds that show a strong selective cytotoxicity in GBM cells with limited systemic toxicity in animals. Ongoing studies are investigating the therapeutic potential of EA01 and EA02 in orthotopic xenografts in vivo.

CBL mutations drive PI3K/AKT signaling via increased interaction with LYN and PIK3R1

Blood ◽  
2021 ◽  
Author(s):  
Roger Belizaire ◽  
Sebastian Hassan John Koochaki ◽  
Namrata D. Udeshi ◽  
Alexis Vedder ◽  
Lei Sun ◽  
...  
Keyword(s):  
Cell Lines ◽  
Ubiquitin Ligase ◽  
Therapeutic Potential ◽  
Mutant Cell ◽  
E3 Ubiquitin Ligase ◽  
Akt Signaling ◽  
Allelic Series ◽  
Genetic Ablation

CBL encodes an E3 ubiquitin ligase and signaling adaptor that regulates receptor and non-receptor tyrosine kinases. Recurrent CBL mutations occur in myeloid neoplasms, including 10-20% of chronic myelomonocytic leukemia (CMML) cases, and selectively disrupt the protein's E3 ubiquitin ligase activity. CBL mutations have been associated with poor prognosis, but the oncogenic mechanisms and therapeutic implications of CBL mutations remain incompletely understood. We combined functional assays and global mass spectrometry to define the phosphoproteome, CBL interactome, and mechanism of signaling activation in a panel of cell lines expressing an allelic series of CBL mutations. Our analyses revealed that increased LYN activation and interaction with mutant CBL are key drivers of enhanced CBL phosphorylation, PIK3R1 recruitment, and downstream PI3K/AKT signaling in CBL-mutant cells. Signaling adaptor domains of CBL, including the tyrosine-kinase binding domain, proline-rich region, and C-terminal phosphotyrosine sites, were all required for the oncogenic function of CBL mutants. Genetic ablation or dasatinib-mediated inhibition of LYN reduced CBL phosphorylation, CBL-PIK3R1 interaction, and PI3K/AKT signaling. Furthermore, we demonstrated in vitro and in vivo antiproliferative efficacy of dasatinib in CBL-mutant cell lines and primary CMML. Overall, these mechanistic insights into the molecular function of CBL mutations provide rationale to explore the therapeutic potential of LYN inhibition in CBL-mutant myeloid malignancies.

CDK12 inhibition mediates DNA damage and is synergistic with sorafenib treatment in hepatocellular carcinoma

Gut ◽  
2019 ◽  
Vol 69 (4) ◽  
pp. 727-736 ◽  
Author(s):  
Cun Wang ◽  
Hui Wang ◽  
Cor Lieftink ◽  
Aimee du Chatinier ◽  
Dongmei Gao ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Dna Damage ◽  
Cell Lines ◽  
Synergistic Effects ◽  
Loss Of Function ◽  
Bioinformatics Analyses ◽  
Sorafenib Treatment ◽  
Hcc Cells

ObjectivesHepatocellular carcinoma (HCC) is one of the most frequent malignancies and a major leading cause of cancer-related deaths worldwide. Several therapeutic options like sorafenib and regorafenib provide only modest survival benefit to patients with HCC. This study aims to identify novel druggable candidate genes for patients with HCC.DesignA non-biased CRISPR (clustered regularly interspaced short palindromic repeats) loss-of-function genetic screen targeting all known human kinases was performed to identify vulnerabilities of HCC cells. Whole-transcriptome sequencing (RNA-Seq) and bioinformatics analyses were performed to explore the mechanisms of the action of a cyclin-dependent kinase 12 (CDK12) inhibitor in HCC cells. Multiple in vitro and in vivo assays were used to study the synergistic effects of the combination of CDK12 inhibition and sorafenib.ResultsWe identify CDK12 as critically required for most HCC cell lines. Suppression of CDK12 using short hairpin RNAs (shRNAs) or its inhibition by the covalent small molecule inhibitor THZ531 leads to robust proliferation inhibition. THZ531 preferentially suppresses the expression of DNA repair-related genes and induces strong DNA damage response in HCC cell lines. The combination of THZ531 and sorafenib shows striking synergy by inducing apoptosis or senescence in HCC cells. The synergy between THZ531 and sorafenib may derive from the notion that THZ531 impairs the adaptive responses of HCC cells induced by sorafenib treatment.ConclusionOur data highlight the potential of CDK12 as a drug target for patients with HCC. The striking synergy of THZ531 and sorafenib suggests a potential combination therapy for this difficult to treat cancer.

A Phase II Study of PXD101 in Advanced Multiple Myeloma.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3583-3583 ◽  
Author(s):  
Daniel Sullivan ◽  
Seema Singhal ◽  
Michael Schuster ◽  
James Berenson ◽  
Peter Gimsing ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Lines ◽  
Stable Disease ◽  
Progressive Disease ◽  
Synergistic Effects ◽  
Objective Response ◽  
Study Drug ◽  
Primary Objective

Abstract Background: PXD101 is a small molecule HDAC inhibitor of the hydroxamate class, which demonstrates broad anti-neoplastic activity in vitro and in vivo. PXD101 has antiproliferative activity on multiple myeloma cell lines, and shows additive/synergistic effects with standard agents used in myeloma, against these cell lines. PXD101 is being tested as monotherapy and in combination with standard agents for treatment of multiple myeloma. Methods: The primary objective of this study was to assess the activity of PXD101 alone or with dexamethasone, in multiple myeloma patients (pts) who have failed at least 2 prior therapies. Response was measured using the Blade criteria. PXD101 was administered as a 30-min IV infusion on Days 1–5 of a 3-wk cycle, at a dose of 1000 mg/m2/d (900 mg/m2/d in earlier patients). Patients are initially treated with PXD101 alone for two cycles. At the end of cycle two and every cycle thereafter, pts are evaluated for tumor response and continue on the study as follows: pts with objective response or stable disease continue on PXD101 monotherapy, while pts who have progressive disease (PD) are treated with a combination of PXD101 + dexamethasone (Dex). Dex was given orally 40 mg daily on Days 2–5 and 10–13 of the treatment cycle. Results: To date, 24 pts have been enrolled, 19 for which data are currently available. These pts have received a median of 5 (range 2–10) prior therapies. Seventeen pts are evaluable, 12 of whom are evaluable for ≥ 2 cycles, and 5 evaluable for 1 cycle only; 2 pts are unevaluable due to inconsistent baseline that prevented response assessment. Of the 5 pts evaluable for 1 cycle only, 4 discontinued due to PD and one withdrew from study. The 12 pts evaluable for ≥ 2 cycles received a median of 4 treatment cycles (range 2–12); 6 of these patients went on to receive PXD101+Dex. In these 12 pts, duration of PXD101 monotherapy was for 2–4 cycles, with almost all pts (10) receiving only 2 cycles. PXD101+Dex treatment in 6 pts was for 1–10 cycles (10, 6, 4, 4, 3, and 1). In 12 pts on monotherapy for ≥ 2 cycles, there were 6 SD (duration 6–12 wks) and 6 PD. The short duration of SD in PXD101 monotherapy was attributed to patient withdrawal or moving to Dex addition in spite of disease stabilization. All 6 pts receiving PXD101+Dex had previously received at least 2 Dex-containing regimens. One pt had MR (duration 6 wks), and 5 pts had SD. One pt has had SD for 35 wks, with 90% decrease in serum M-component sustained in the last 12 wks; another pt has had SD for 15 wks. In 69 cycles of treatment there were 7 Grade 3/4 adverse events assessed by the investigator as potentially related to study drug. These include anemia (2), infection, respiratory distress, hyperglycemia, thrombocytopenia, and fatigue. Conclusions: PXD101 treatment has resulted in stabilization of advanced and progressive disease, providing clinical benefit to patients. PXD101 combination with dexamethasone led to an MR as well as long duration of stable disease in patients who have previously received multiple Dex regimens. These observations support the continued exploration of PXD101 in combination with other agents for treatment of multiple myeloma.

NPI-2358, a Novel Vascular Disrupting Agent Blocks Growth and Angiogenesis in Multiple Myeloma Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3842-3842
Author(s):  
Dharminder Chauhan ◽  
Ajita V. Singh ◽  
Madhavi Bandi ◽  
Noopur Raje ◽  
Robert L Schlossman ◽  
...  
Keyword(s):  
Cell Lines ◽  
Annexin V ◽  
Vascular Endothelial ◽  
Caspase 9 ◽  
Migration Assays ◽  
Induced Apoptosis ◽  
Rpmi 8226 ◽  
Anti Tumor Activity

Abstract Abstract 3842 Poster Board III-778 Background and Rationale Vascular disrupting agents (VDAs) act via selectively disrupting established tumor vasculature and have shown remarkable clinical success as anti-cancer therapies. NPI-2358 is a novel VDA with a distinct structure and mechanism of action from other available VDAs. NPI-2358 binds to the colchicine-binding site of beta-tubulin preventing polymerization and disrupting the cytoplasmic microtubule network, thereby causing loss of vascular endothelial cytoskeletal function, and inducing cytotoxicity in cancer cells. Here, we examined the anti-angiogenic and anti-tumor activity of NPI-2358 in multiple myeloma (MM) cells using both in vitro and in vivo model systems. Material and Methods We utilized MM.1S, MM.1R, RPMI-8226, U266, and INA-6 human MM cell lines, as well as purified tumor cells from MM patients relapsing after prior anti-MM therapies. Cell viability/apoptosis assays were performed using MTT, trypan blue exclusion, and Annexin V/PI staining. Angiogenesis was measured in vitro using Matrigel capillary-like tube structure formation assays: Since human vascular endothelial cells (HUVECs) plated onto Matrigel differentiate and form capillary-like tube structures similar to in vivo neovascularization, this assay measures anti-angiogenic effects of drugs/agents. Migration assays were performed using transwell insert assays. Immunoblot analysis was performed using antibodies to caspase-8, caspase-9, caspase-3, PARP, Bcl-2, Bax, pJNK and GAPDH. Statistical significance was determined using a Student t test. Results Treatment of MM.1S, RPMI-8226, MM.1R, INA-6, and KMS-12BM with NPI-2358 for 24h induces a dose-dependent significant (P < 0.005) decrease in viability of all cell lines (IC50 range: 5-8 nM; n=3). To determine whether NPI-2358-induced decrease in viability is due to apoptosis, MM cell lines were treated with NPI-2358 for 24h; harvested, and analyzed for apoptosis using Annexin V/PI staining. A significant increase in NPI-2358-induced apoptosis was observed in all MM cell lines (% Annexin V+/PI- apoptotic cells: MM.1S, 48 ± 2.3%; MM.1R, 46.6 ± 3.1%; RPMI-8226, 61.7 ± 4.5%; and INA-6, 59.9 ± 3.2%; P < 0.05; n=3). Importantly, NPI-2358 decreased viability of freshly isolated MM cells from patients (IC50 range: 3-7 nM; P < 0.005), without affecting the viability of normal peripheral blood mononuclear cells, suggesting specific anti-MM activity and a favorable therapeutic index for NPI-2358. Examination of in vitro angiogenesis using capillary-like tube structure formation assay showed that even low doses of NPI-2358 (7 nM treatment for 12h; IC50: 20 nM at 24h) significantly decreased tubule formation in HUVECs (70-80% decrease; P < 0.05). Transwell insert assays showed a marked reduction in serum-dependent migration of NPI-2358-treated MM cells (42 ± 2.1% inhibition in NPI-2358-treated vs. control; P < 0.05). NPI-2358 at the concentrations tested (5 nM for 12h) in the migration assays did not affect survival of MM cells (> 95% viable cells). A similar anti-migration activity of NPI-2358 was noted against HUVEC cells (48 ± 1.7% decrease in migration; P < 0.05). Mechanistic studies showed that NPI-2358-induced apoptosis was associated with activation of caspase-8, caspase-9, caspase-3 and PARP. Importantly, treatment of MM.1S cells with NPI-2358 (5 nM) triggered phosphorylation of c-Jun amino-terminal kinase (JNK), a classical stress response protein, without affecting Bcl-2 family members Bax and Bcl-2. Blockade of JNK using dominant negative strategy markedly abrogated NPI-2358-induced apoptosis. Conclusion Our preclinical data provide evidence for remarkable anti-angiogenic and anti-tumor activity of NPI-2358 against MM cells, without significant toxicity in normal cells. Ongoing studies are examining in vivo anti-MM activity of NPI-2358 in animal models. Importantly, a Phase-1 study of NPI-2358 as a single agent in patients with advanced malignancies (lung, prostrate and colon cancer) has already established a favorable pharmacokinetic, pharmacodynamic and safety profile; and, a Phase-2 study of the combination of NPI-2358 and docetaxel in non-small cell lung cancer showed encouraging safety, pharmacokinetic and activity data. These findings, coupled with our preclinical studies, provide the framework for the development of NPI-2358-based novel therapies to improve patient outcome in MM. Disclosures: Chauhan: Nereus Pharmaceuticals, Inc: Consultancy. Lloyd:Nereus Pharmaceuticals, In: Employment. Palladino:Nereus Pharmaceuticals, Inc: Employment. Anderson:Nereus Pharmaceuticals, Inc: Consultancy.

Adaptation of a Xenograft AML Model to Evaluate Chemotherapeutic Efficacy In Vivo

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3304-3304 ◽  
Author(s):  
Mark Wunderlich ◽  
Fu-Sheng Chou ◽  
Mahesh Shrestha ◽  
Benjamin Mizukawa ◽  
James C. Mulloy
Keyword(s):  
Blood Cell ◽  
Treatment Period ◽  
Conflicts Of Interest ◽  
Residual Disease ◽  
Synergistic Effects ◽  
Day Treatment ◽  
Chemotherapeutic Agents ◽  
Mouse Strains

Abstract Abstract 3304 Although significant progress has been made in the treatment of leukemia, relapse continues to be a major problem, particularly in acute myeloid leukemia (AML). The prognosis for relapsed leukemia is poor, indicating an area for potential improvements. However, animal models to study the response of human AML to chemotherapeutics and subsequent relapse are lacking. Recently we developed an improved NOD/SCID mouse with IL2RG knockout and transgenic expression of myelo-supportive cytokines SCF, GM-CSF, and IL-3 (the NSGS mouse). This mouse is remarkable in its ability to accept human AML grafts more efficiently than all other available strains. When coupled with in vitro derived AML cells, the NSGS mouse allows for a more predictable AML model with shorter latency and smaller range of death than in other mouse strains, including NSG mice. Importantly, very low numbers of cells reliably generate fatal AML in roughly 40 days, even in non-irradiated NSGS mice, allowing for rapid experimental conclusions and reduced toxicity. With the benefits of these unique tools, we sought to develop a model system to evaluate the efficacy of chemotherapeutic agents on human AML cells in vivo. Engrafted mice received a chemotherapy regimen over a 5-day treatment period consisting of a daily dose of cytarabine with simultaneous injection of doxorubicin during the first three days. Treated mice experienced striking weight loss during the treatment period with a nadir at days 8–10 post-treatment. Mice recovered body weight within 3 weeks. Serial complete blood counts indicated a rapid transient drop in total white blood cell and neutrophil counts and a delayed transient drop in red blood cell and platelet numbers, reminiscent of the effects observed in patients undergoing chemotherapy. The drugs successfully targeted the cells of the bone marrow, as evidenced by a profound loss of cellularity in treated mice relative to controls. When mice harboring N-Ras(G12D) positive AML cells were treated at early time points post-transplant, a significant reduction of tumor burden was observed in the BM and PB, with the grafts of treated mice essentially undetectable for weeks after treatment cessation. Nevertheless, treated mice inevitably succumbed to disease, although with a significantly prolonged latency compared to mock treated mice. However, when AML cells containing the FLT3-ITD mutation were used, a shift in disease latency was not reproducibly seen. This data correlates well with patient data showing that FLT3-ITD mutant AML has a worse prognosis than AML samples with N-Ras mutations. Importantly, the reappearance of AML within weeks of treatment affords the opportunity to model drug resistance and relapse, as well as the potential synergistic effects of experimental compounds used in combination with traditional chemotherapy. Additionally, the period following treatment may allow for studies of minimal residual disease as well as the testing of potential maintenance therapies. Finally, this approach permits a detailed analysis of the critical few cancer stem cells that remain after induction therapy with the goal of identifying novel compounds capable of targeting these cells. Disclosures: No relevant conflicts of interest to declare.

Preclinical Activity of Brentuximab Vedotin (SGN-35) in Primary Effusion Lymphoma (PEL),

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3728-3728 ◽  
Author(s):  
Shruti Bhatt ◽  
Brittany Ashlock ◽  
Yaso Natkunam ◽  
Juan Carlos Ramos ◽  
Enrique Mesri ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Cell Lines ◽  
Conflicts Of Interest ◽  
Primary Effusion Lymphoma ◽  
Large Cell ◽  
Brentuximab Vedotin ◽  
Antibody Drug Conjugate ◽  
Human Herpes Virus 8

Abstract Abstract 3728 Primary effusion lymphoma (PEL) is a distinct and aggressive subtype of non-Hodgkin lymphoma (NHL) commonly presenting with pleural, peritoneal, or pericardial malignant effusions usually without a contiguous tumor mass. PEL is most commonly diagnosed in HIV-positive patients, accounting for 4% of all NHLs in this population, yet may also develop in immunosuppressed HIV-negative individuals. While Human Herpes Virus 8 (HHV8 or Kaposi's sarcoma-associated herpesvirus) is directly implicated in the oncogenesis of this lymphoma, most PEL cases are also associated with Epstein-Barr virus and the combination of the two may facilitate transformation. The tumor cells exhibit plasmablastic features and express CD45, CD38, CD138, HHV8 and CD30. PEL is an aggressive tumor characterized by a short median survival of only 6 months with current therapeutic approaches underscoring the urgent need for development of new therapeutics. Brentuximab vedotin (SGN-35) is an antibody-drug conjugate (ADC) comprised of an anti-CD30 monoclonal antibody cAC10 conjugated by a protease-cleavable dipeptide linker to a potent cell killing agent monomethyl auristatin E (MMAE). Following binding to CD30, brentuximab vedotin is rapidly internalized and is transported to lysosomes, where the peptide linker is selectively cleaved allowing binding of the released MMAE to tubulin and leading to cell cycle arrest and apoptosis. Brentuximab vedotin was recently reported to have promising antitumor activity in CD30 expressing tumors, such as Hodgkin and Anaplastic large cell lymphomas. Since PEL tumors are reported to express CD30, we have hypothesized that brentuximab vedotin might be effective in the treatment of this NHL subtype. Initially, we have confirmed by flow cytometry the expression of CD30 on PEL cell lines (UM-PEL 1, UM-PEL 3, BC-1 and BC-3), and by review of immunohistochemistry and flow cytometry results in patients with previous diagnosis of PEL at our institution. To examine in vitro potency of brentuximab vedotin, UM-PEL 1, UM-PEL 3, BC-1 and BC-3 PEL cell lines were treated with brentuximab vedotin at concentration ranging from 0–100 micrograms/ml. Staining with YO-PRO and Propidium Iodide (PI) demonstrated dose dependent cell apoptosis and death in all the cell lines at 72 hours post treatment. In contrast, control IgG conjugated with MMAE failed to induce apoptosis and cell death of PEL cell lines confirming specific brentuximab vedotin cytotoxicity. Furthermore, brentuximab vedotin decreased proliferation of PEL cells at 48 hours leading to a complete proliferation arrest at 72 hours, as measured by MTS assay. These effects were absent after equivalent doses of control IgG conjugated drug treatment. Supportive to this, labeling of cells with PI to detect active DNA content by flow cytometry showed that bretuximab vedotin induced growth arrest in G2/M phase. To further establish the anti-tumor potential of brentuximab vedotin in vivo, we used the direct xenograft UM-PEL 1 model, established in our laboratory (Sarosiek, PNAS 2010), which mimics human PEL tumors. UM-PEL 1 bearing mice were injected intraperitoneally 3 times a week with brentuximab vedotin or control IgG conjugated MMAE for 4 weeks. Brentuximab vedotin treatment markedly prolonged overall survival of UM-PEL-1 bearing mice compared to controls (p Disclosures: No relevant conflicts of interest to declare.

Sign in / Sign up

Export Citation Format

Share Document