Targeting BET Bromodomains in Pre-Clinical Models of Burkitt Lymphoma

Abstract Background: Burkitt lymphoma (BL) is the most common NHL type in children. Although treatment for pediatric BL has improved significantly, there is an urgent need for novel therapies that reduce the toxicity of modern treatment regimens and improve on the dismal survival observed in the relapsed/refractory setting where only about 20-30% of patients survive their disease. Recent reports have implicated co-activation of c-Myc and PI3K in Burkitt lymphomagenesis. Genomic analysis of recurrent oncogenic mutations in BL have identified tonic B-cell receptor signaling and the over-expression of Myc induced microRNAs from the MIR17-92 family, e.g. mir17 and mir19, as possible mechanisms of PI3K activation in BL. Mir17 and mir19, have been implicated in Burkitt lymphomagenesis and their overexpression may be associated with a higher risk of relapse. The protein phosphatase and tensin homolog (PTEN) is a major regulator of PI3K pathway activation. MIR17-92 cluster members have been shown to target PTEN leading to increased PI3K activation. We have previously identified increased expression of mir17 and mir19 along with increased activation of AKT in cell line models of chemotherapy resistant BL suggesting a potential mechanism for increased resistance. BET bromodomains interact with chromatin and enhance transcriptional activation of numerous genes including c-Myc. Thus, BET bromodomains represent a promising target in BL. To investigate the effects of inhibition of c-Myc driven activation of the PI3K/AKT/mTOR pathway, we characterized the activity of the highly potent small molecule bromodomain inhibitor JQ1 in chemotherapy sensitive and resistant BL cell lines. Additionally, we analyzed the ability to enhance anti-lymphoma activity of PI3K/Akt/mTOR pathway inhibition in BL by the combination of BET bromodomain inhibition and targeted inhibition of the PI3K/AKT/mTOR pathway. Methods: The in vitro activity of JQ1 was investigated in the BL cell lines Raji, Raji 4RH (chemotherapy-rituximab resistant), Raji 8RH (rituximab resistant), Ramos, and Daudi. Cell Viability following exposure to JQ1 alone and in combination with the PI3K/mTOR inhibitor omipalisib (GSK458)) was analyzed using Cell-Titer Glo or Alamar Blue assays following 24, 48, and 72 hour exposure over a range of inhibitor concentrations. Induction of apoptosis was analyzed using western blotting for cleaved PARP. C-Myc expression following JQ1 exposure was determined by western blot following 48 hour JQ1 exposure. The effect of JQ1 exposure on the expression of c-Myc induced microRNA expression was determined by qRT-PCR in cells exposed to JQ1 for 48hours. Synergy of combination exposures was determined using CalcuSyn to generate combination index (CI) values. Results: In vitro exposure of BL cell lines to JQ1 for 24, 48, and 72 hours resulted in a significant dose and time dependent decrease in viable cells (72 hour IC50 values: Raji 0.12µM, Raji 4RH 1.7µM, Raji 8RH 0.7µM, Ramos 0.22µM and Daudi 4µM). There was an increase in cleaved PARP after 72 hour exposure indicating induction of apoptosis. While single agent effect was seen in the resistant Raji 4RH cell line, activity was noted to primarily occur at the higher end of the dosing. Western blot analysis demonstrated a reduction in c-Myc expression following exposure to JQ1 1µM for 24 hours (relative band intensity normalized to control: Raji=0.12, Raji 4RH=0.18, Raji 8RH=0.11). qPCR showed a reduction in Mir17 relative transcription levels after 48 hours of exposure to JQ1 2.5mM (relative expression compared to control: Raji=0.72, Raji 4RH=0.98, Raji 8RH=0.83, Ramos=0.57, Daudi=0.46). When combined with omipalisib, an increased effect on cell viability was noted. The combination effect was noted to be synergistic (CI<0.9) at multiple dose combinations while other combinations exhibited primarily additive effects. Conclusion: In vitro inhibition of BET bromodomains with JQ1 results in a decrease in c-Myc expression and a decrease in c-Myc dependent miR expression with impaired proliferation and induction of apoptosis in chemotherapy-sensitive and -resistant BL cell lines. Augmented, and in some cases synergistic, activity is also noted with dual inhibition of BET bromodomains and the PI3K/Akt/mTOR pathway in BL cell lines. Disclosures No relevant conflicts of interest to declare.

Download Full-text

PI3K/Akt/mTOR Pathway Inhibition in Chemotherapy-Sensitive and -Resistant Models of Burkitt Lymphoma

Blood ◽

10.1182/blood.v126.23.1558.1558 ◽

2015 ◽

Vol 126 (23) ◽

pp. 1558-1558 ◽

Cited By ~ 1

Author(s):

Maria Bhatti ◽

Thomas Ippolito ◽

Cory Mavis ◽

Matthew J. Barth

Keyword(s):

Cell Cycle ◽

Flow Cytometry ◽

Cell Viability ◽

Cell Line ◽

Cell Lines ◽

Propidium Iodide ◽

Mtor Pathway ◽

Propidium Iodide Staining ◽

Induction Of Apoptosis ◽

Pre Treatment

Abstract Introduction: Burkitt lymphoma (BL) is the most common form of B-cell non-Hodgkin lymphoma (B-NHL) in children. Despite significant improvements in survival with de novo disease, treatment of relapsed or refractory BL remains a significant hurdle with survival in only about 20% of patients. Novel therapeutic approaches are necessary to improve outcomes in this group of childhood B-NHL patients with the worst prognosis. Recent literature has identified a high rate of recurrent mutations that result in activation of the PI3K/Akt pathway in BL and have implicated activation of PI3K/Akt in coordination with Myc in BL lymphomagenesis. Our laboratory has developed rituximab and chemotherapy resistant cell line models and subsequently found that these cell lines exhibit increased activation of Akt. We hypothesized that increased activation of Akt may be contributing to chemoresistance and that targeting the PI3K/Akt/mTOR pathway may increase chemoresponsiveness. To that end, we have investigated the effect of inhibiting the PI3K/Akt/mTOR pathway with either the PI3K-delta inhibitor idelalisib or the pan-PI3K/mTOR inhibitor BEZ-235 in cell line models of BL. Methods: The in vitro effect of idelalisib or BEZ-235 was investigated in BL cell lines including Raji, Raji 2R and Raji 4RH (rituximab-chemotherapy resistant), Raji 7R and Raji 8RH (rituximab resistant), Ramos and Daudi. Cell viability following inhibitor exposure was assessed by Alamar blu and cell-titer glo assays. The effect of inhibitor exposure on cell cycle progression was determined by flow cytometry using propidium iodide staining. Inhibition of Akt activation following inhibitor exposure was determined using phospho-flow cytometry. The activity of cytotoxic chemotherapeutic agents following inhibition by idelalisib or BEZ-235 was assessed using Alamar blu and cell titer glo assays. Results: In vitro exposure of BL cell lines to idelalisib in concentrations from 0.1-100µM for 24, 48 or 72 hours resulted in a dose and time-dependent decrease in viable cells in all cell lines tested with IC50 concentrations of 60-300uM. Pre-treatment with the pan-caspase inhibitor QVD resulted in a small reversal in the decrease in cell viability suggesting only a minimal portion of the activity was caspase dependent. When induction of apoptosis was measured using annexin V-propidium iodide staining, little induction of apoptosis was observed with single agent idelalisib at concentrations up to 100uM. Determination of cell cycle progression following exposure to idelalisib at 1, 10, 50 or 100 uM for 24, 48 or 72 hours indicated a time and dose dependent cell cycle arrest in all cell lines. In chemotherapy-sensitive cell lines the arrest was primarily noted in G1, while the chemotherapy-resistant Raji 2R and Raji 4RH cell lines exhibited arrest primarily in G2/M. A significant reduction in cell viability following chemotherapy exposure for 48 hours was noted in chemotherapy resistant Raji 2R cells following pre-treatment for 48 hours with idelalisib 10uM compared to non-idelalisib exposed cells (doxorubicin 10uM 55% vs 77%, p<0.001; vincristine 0.05uM, 48% vs 61%, P<0.001). At higher idelalisib pre-treatment concentrations (50uM) additional synergistic activity was observed in Raji 2R cells (cisplatin 48% vs 61%, p<0.001; dexamethasone 67% vs 87%, p<0.01). To further assess the effect of dual inhibition of PI3K and mTOR, cell lines were exposed to the dual inhibitor BEZ-235. BEZ-235 exhibited a more potent decrease in cell viability compared to idelalisib with activity at nM concentrations. Unlike idelalisib, exposure to BEZ-235 resulted in significant induction of apoptosis by Annexin V-propidium iodide staining. BEZ-235 also exhibited synergistic activity in combination with chemotherapy in all cell lines. At equivalent dosing, BEZ-235 exposure resulted in a more significant decrease in Akt phosphorylation compared to idelalisib as determined by flow cytometry for p-Akt at Ser and Thr phosphorylation sites. Conclusions: Chemotherapy sensitive and resistant BL cell line models are susceptible to inhibition of the PI3K/Akt/mTOR pathway. Targeted inhibition of this pathway leads to a decrease in AKT activation, decrease in cell viability, cell cycle arrest and an increase in sensitivity to cytotoxic chemotherapeutic agents. Broader inhibition of both PI3K and mTOR is more effective than more targeted inhibition of PI3K-delta alone. Disclosures No relevant conflicts of interest to declare.

Download Full-text

Omipalisib (GSK458), a Dual an-PI3K/mTOR Inhibitor, Exhibits in Vitro and In Vivo activity in Chemotherapy-Sensitive and -Resistant Models of Burkitt Lymphoma

Blood ◽

10.1182/blood-2018-99-119048 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 2951-2951 ◽

Cited By ~ 1

Author(s):

Thomas Ippolito ◽

Cory Mavis ◽

Juan Gu ◽

Francisco J. Hernandez-Ilizaliturri ◽

Matthew J. Barth

Keyword(s):

Cell Cycle ◽

Flow Cytometry ◽

Cell Line ◽

Burkitt Lymphoma ◽

Mtor Inhibitor ◽

Mtor Pathway ◽

In Vitro Activity ◽

Induction Of Apoptosis

Abstract Background: Reports of recurrent genomic alterations in Burkitt lymphoma (BL) have identified multiple recurrent alterations that result in activation of PI3K highlighting the importance of the PI3K/AKT/mTOR pathway in Burkitt lymphomagenesis. In a cell line model of resistant BL, we have previously identified an increase of PI3K/AKT/mTOR pathway activation suggesting a role in therapy resistance. While inhibition of PI3K-delta using the isoform specific inhibitor idelalisib has demonstrated clinical activity in indolent lymphomas, limited single agent activity has been observed in more aggressive variants. Pre-clinical investigation of idelalisib in BL indicated similar somewhat limited in vitro activity with synergistic activity in combination with chemotherapy. Broader inhibition of both upstream PI3K and downstream mTOR may exhibit more significant anti-lymphoma activity. Objectives: Investigate the in vitro and in vivo activity of the dual pan-PI3K/mTOR inhibitor omipalisib (GSK458) in chemotherapy-sensitive and -resistant BL cell line models. Methods: Experiments were conducted in Raji, Raji 4RH (chemotherapy-rituximab resistant), Ramos, and Daudi BL cells. Cell viability following exposure to omipalisib +/- chemotherapy was analyzed using Cell-Titer Glo and Alamar blu assays. Induction of apoptosis was assessed by flow cytometry for Annexin V (AV)-propidium iodide (PI) staining. Downstream effects of omipalisib on PI3K/Akt/mTOR signaling were analyzed using western blotting. Cell cycle analysis was performed by flow cytometry using PI staining. Synergy of combination exposures was determined by calculation of the combination index (CI) using CalcuSyn software. In vivo activity was evaluated using disseminated Raji and subcutaneous Ramos SCID mouse xenograft models. The survival end point was hind limb paralysis in the disseminated model and tumor diameter >2cm in the subcutaneous model. Mice were treated with vehicle or omipalisib daily by oral gavage. Median survival was compared by Kaplan-Meier analysis. Results: Exposure of BL cells to omipalisib for 24-72 hours resulted in a dose- and time-dependent decrease in viable cells at nM concentrations (48h IC50 values: Raji=1.2uM, Raji 4RH=0.02uM, Ramos=0.01uM, Daudi=0.01uM) (Figure 1A). Marked induction of apoptosis occurred following 72h exposure to omipalisib primarily in chemosensitive cells with half-maximal effect noted at approximately 200nM, but requiring significantly higher concentrations to induce apoptosis in therapy resistant Raji 4RH cells (%AV positive at 200nM: Raji=40.7%, Raji 4RH=4.4%, Ramos=59.4% and Daudi=46.9%). Downstream of PI3K/Akt/mTOR, S6 and GSK3β showed reduced phosphorylation after 30 minute omipalisib exposure. G1 cell cycle arrest occurred in all cell lines following exposure to omipalisib for 72 hours; however, chemotherapy-resistant Raji 4RH cells arrested in G2/M at higher concentrations. BL cells exposed to omipalisib in combination with either doxorubicin or dexamethasone, exhibited synergistic anti-tumor activity (CI<0.9) with synergistic induction of apoptosis in therapy sensitive cells exposed to omipalisib and chemotherapy. NOD-SCID mice injected via tail vein with Raji-luc (provided by Dr. Mitchell Cairo) and treated with omipalisib demonstrated decreased luciferase signal compared to controls (Figure 1C) while mice with established subcutaneous Ramos xenografted tumors treated with omipalisib exhibited slower tumor progression compared to controls (Figure 1B), though with only modest prolongation of survival (median 28 vs 34 days, n=15/group, p<0.05). Conclusion: Dual PI3K-mTOR inhibitor omipalisib suppresses the PI3K/Akt/mTOR pathway leading to induction of apoptosis, impaired BL cell proliferation in vitro and in vivo and exhibits synergistic in vitro activity when combined with cytotoxic chemotherapy highlighting the relevance of PI3K/Akt/mTOR pathway inhibition as a potential therapeutic option in BL. Disclosures No relevant conflicts of interest to declare.

Download Full-text

Temozolomide sensitivity of malignant glioma cell lines – a systematic review assessing consistencies between in vitro studies

BMC Cancer ◽

10.1186/s12885-021-08972-5 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Michael T. C. Poon ◽

Morgan Bruce ◽

Joanne E. Simpson ◽

Cathal J. Hannan ◽

Paul M. Brennan

Keyword(s):

Cell Viability ◽

Malignant Glioma ◽

Cell Line ◽

Cell Lines ◽

Glioma Cell ◽

Glioma Cell Line ◽

In Vitro Studies ◽

Experimental Conditions ◽

Glioma Cell Lines

Abstract Background Malignant glioma cell line models are integral to pre-clinical testing of novel potential therapies. Accurate prediction of likely efficacy in the clinic requires that these models are reliable and consistent. We assessed this by examining the reporting of experimental conditions and sensitivity to temozolomide in glioma cells lines. Methods We searched Medline and Embase (Jan 1994-Jan 2021) for studies evaluating the effect of temozolomide monotherapy on cell viability of at least one malignant glioma cell line. Key data items included type of cell lines, temozolomide exposure duration in hours (hr), and cell viability measure (IC50). Results We included 212 studies from 2789 non-duplicate records that reported 248 distinct cell lines. The commonest cell line was U87 (60.4%). Only 10.4% studies used a patient-derived cell line. The proportion of studies not reporting each experimental condition ranged from 8.0–27.4%, including base medium (8.0%), serum supplementation (9.9%) and number of replicates (27.4%). In studies reporting IC50, the median value for U87 at 24 h, 48 h and 72 h was 123.9 μM (IQR 75.3–277.7 μM), 223.1 μM (IQR 92.0–590.1 μM) and 230.0 μM (IQR 34.1–650.0 μM), respectively. The median IC50 at 72 h for patient-derived cell lines was 220 μM (IQR 81.1–800.0 μM). Conclusion Temozolomide sensitivity reported in comparable studies was not consistent between or within malignant glioma cell lines. Drug discovery science performed on these models cannot reliably inform clinical translation. A consensus model of reporting can maximise reproducibility and consistency among in vitro studies.

Download Full-text

In Vitro Cytotoxicity of Oleanolic/Ursolic Acids-Loaded in PLGA Nanoparticles in Different Cell Lines

Pharmaceutics ◽

10.3390/pharmaceutics11080362 ◽

2019 ◽

Vol 11 (8) ◽

pp. 362 ◽

Cited By ~ 20

Author(s):

Amélia M. Silva ◽

Helen L. Alvarado ◽

Guadalupe Abrego ◽

Carlos Martins-Gomes ◽

Maria L. Garduño-Ramirez ◽

...

Keyword(s):

Cell Viability ◽

Cell Line ◽

Cell Lines ◽

Specific Activity ◽

Polymeric Nanoparticles ◽

Hepatoma Cell ◽

Plga Nanoparticles ◽

Hepatoma Cell Line ◽

Human Hepatoma Cell

Oleanolic (OA) and ursolic (UA) acids are recognized triterpenoids with anti-cancer properties, showing cell-specific activity that can be enhanced when loaded into polymeric nanoparticles. The cytotoxic activity of OA and UA was assessed by Alamar Blue assay in three different cell lines, i.e., HepG2 (Human hepatoma cell line), Caco-2 (Human epithelial colorectal adenocarcinoma cell line) and Y-79 (Human retinoblastoma cell line). The natural and synthetic mixtures of these compounds were tested as free and loaded in polymeric nanoparticles in a concentration range from 2 to 32 µmol/L. The highest tested concentrations of the free triterpene mixtures produced statistically significant cell viability reduction in HepG2 and Caco-2 cells, compared to the control (untreated cells). When loaded in the developed PLGA nanoparticles, no differences were recorded for the tested concentrations in the same cell lines. However, in the Y-79 cell line, a decrease on cell viability was observed when testing the lowest concentration of both free triterpene mixtures, and after their loading into PLGA nanoparticles.

Download Full-text

The Sumoylation Inhibitor TAK-981 in Combination with the CD19-Targeting Antibody Tafasitamab Shows Enhanced Anti-Tumor Activity in Preclinical B-Cell Lymphoma Models

Blood ◽

10.1182/blood-2021-150718 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 2268-2268

Author(s):

Maria Patra-Kneuer ◽

Akito Nakamura ◽

Keli Song ◽

Stephen Grossman ◽

Andrea Polzer ◽

...

Keyword(s):

Cell Viability ◽

Tumor Cells ◽

Cell Lines ◽

Burkitt Lymphoma ◽

B Cell Lymphoma ◽

Lymphoma Cells ◽

Effector Cells ◽

Xenograft Models ◽

Development Center

Abstract Introduction TAK-981 is a first-in-class small molecule inhibitor of the SUMO activating enzyme currently in Phase I/II clinical trials. TAK-981 has been shown to increase NK cell activation and M1 macrophage polarization via upregulation of Type I interferon (IFN) signaling, leading to enhanced antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) in combination with rituximab (Nakamura 2019, AACR). Tafasitamab (MOR208) is a CD19-targeting antibody with enhanced Fc effector function mediating ADCC, ADCP and direct cytotoxic activities against B-lymphoma cells. Based on the Phase II clinical study L-MIND (Salles et al., 2020 and Duell et al., 2021), tafasitamab in combination with lenalidomide received accelerated approval by the Food and Drug Administration for the treatment of transplant-ineligible adult patients with relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL). Due to the potential for TAK-981 to enhance the activity of tafasitamab via activation of innate effector cells, we aimed to investigate the effects of this drug combination on ADCC, ADCP and tumor cell viability in vitro. Additionally, combinatorial activity of TAK-981 plus tafasitamab was evaluated in lymphoma xenograft models. Methods A panel of 9 aggressive lymphoma cell lines was analyzed (7 DLBCL and 2 Burkitt lymphoma). For ADCC, PBMC effector cells from healthy human donors were pre-treated with 0.1 or 1 µM TAK-981 or dimethyl sulfoxide (DMSO) control for 24 hours. Tumor cells were incubated with/without 1 nM tafasitamab in the presence of TAK-981 pretreated PBMCs at effector-to-target (E:T) ratios of 5:1 to 10:1 for 2 hours. Degranulation of NK cells was determined via CD107a surface expression after co-incubation of TAK-981 pre-treated PBMCs with tumor cells and 0.1 or 10 nM tafasitamab for 3 hours. Cytokine levels in the supernatant were investigated upon incubation of PBMCs with lymphoma cells, 1 µM TAK-981 and/or 10 nM tafasitamab for 24 hours. For the ADCP assays, in vitro differentiated macrophages were treated with 1 µM TAK-981 for 24 hours. Next, macrophages were incubated with lymphoma cells and 1 or 10 nM tafasitamab at an E:T ratio of 2:1 for 3 hours. For cell viability assays, tumor cells were treated with 1-1000 nM TAK-981 and/or 5 nM tafasitamab for 24 hours in the absence of effector cells. Cytotoxicity, phagocytosis, degranulation and cytokine release were analyzed by flow cytometry. Cell viability was assessed by determination of ATP levels. For in vivo analysis, effects of TAK-981 (7.5 mg/kg IV twice weekly) in combination with tafasitamab (3, 10 or 20 mg/kg IP twice weekly) on tumor growth were evaluated in Daudi and WSU-DLCL2 xenograft models of Burkitt lymphoma and DLBCL grown in SCID mice. Results In ADCC experiments, increased cytotoxicity was observed upon combination treatment with TAK-981 and tafasitamab compared to the respective mono treatments in 5/8 tested lymphoma cell lines (Daudi, SU-DHL-2, SU-DHL-6, TMD8, OCI-LY10). Moreover, TAK-981 plus tafasitamab enhanced degranulation of NK cells and cytokine release compared to mono treatments. In ADCP assays, combination of TAK-981 and tafasitamab resulted in increased phagocytosis rates in comparison to mono treatments in 2/2 tested cell lines (Daudi, Ramos). Cell viability analysis revealed a combination benefit by increased direct cytotoxic effects against SU-DHL-6 cells. Finally, TAK-981 and tafasitamab were investigated in Daudi and WSU-DLCL2 xenograft models with 3 weeks of dosing. In the Daudi model, the combination treatments of TAK-981 with 10 or 20 mg/kg tafasitamab performed better than either treatment alone, and in the WSU-DLCL2 model, the combination treatments of TAK-981 with 3, 10 or 20 mg/kg tafasitamab performed better than the single agent treatments. Conclusions The combination of TAK-981 with tafasitamab significantly enhanced anti-tumor effects compared to the respective monotherapies in vitro and in vivo. These preclinical data support a clinical evaluation of this drug combination in patients with lymphoma including aggressive subtypes such as Burkitt lymphoma and DLBCL. The study was funded by MorphoSys AG and Takeda Development Center Americas, Inc. Disclosures Patra-Kneuer: MorphoSys AG: Current Employment. Nakamura: Takeda Development Center Americas, Inc.: Current Employment. Song: Takeda Pharmaceuticals International Co.: Current Employment. Grossman: Takeda Development Center, Cambridge MA: Current Employment. Polzer: MorphoSys: Current Employment. Ginzel: MorphoSys: Current Employment. Steidl: MorphoSys AG: Current Employment. Berger: Takeda Development Center Americas, Inc.: Current Employment. Proscurshim: Takeda Pharmaceuticals: Current Employment, Current holder of individual stocks in a privately-held company. Heitmüller: MorphoSys AG: Current Employment.

Download Full-text

MiR-624-5p enhances cell resistance against cisplatin via PDGFRA/Stat3/PI3K axis in ovarian cancer

Tropical Journal of Pharmaceutical Research ◽

10.4314/tjpr.v19i4.3 ◽

2020 ◽

Vol 19 (4) ◽

pp. 691-698

Author(s):

Lin I-Ju ◽

Tian YongJie

Keyword(s):

Ovarian Cancer ◽

Cell Viability ◽

Cell Line ◽

Cell Lines ◽

Clinical Stage ◽

Luciferase Reporter Assay ◽

Luciferase Reporter ◽

Reporter Assay

Purpose: The purpose of this study was to evaluate the role of miR-624-5p in ovarian cancer.Methods: MiR-624-5p expression in ovarian cancer {OC) cell lines and normal cells (NCs) was evaluated and compared the differential miR-624-5p in OC A2780 cells and cisplatin-resistant OC cell line (A2780/DDP). CCK-8 was used to evaluate changes in cell viability of the A2780 and A2780/DDP cell lines as well as silenced miR-624-5p. Western Blot examined the Stat3 and phosphorylated Pi3k. The binding between PDGFRA and miR-624-5p was predicted on Targetscan and verified through Luciferase Reporter Assay. The role of PDGFRA in A2780/DDP by overexpressing PDGFRA was evaluated by RT-qPCR and CCK-8 assays. RT-qPCR assay also measured miR-624-5p expression responsive to different dosages of cisplatin and CCK8 examined viability levels correspondingly. In addition, the interplay of PDGFRA and miR-624-5p by combined downregulation of both miR-624-5pand PDGFRA were evaluated.Results: OC cells had higher miR-624-5p expression than NCs but lower compared to cisplatinresistant A2780/DDP cells. A2780/DDP cells had higher viability than OC cell line A2780. Stat3 and phosphorylated PI3K were activated in A2780/DDP cells. Silencing miR-624-5p led to lower viability inA2780/DDP cells. miR-624-5p expression dropped as the cisplatin concentration increased, resulting in decreasing viability respectively. Luciferase Reporter assay validated the binding of miR-624-5p and PDGFRA in A2780/DDP cells. Overexpressed PDGFRA induced lower cell viability in A2780/DDP cells. Downregulation of PDGFRA partially restored the lowered viability and inhibited Stat3 as well as phosphorylated Pi3k induced by miR-624-5p inhibitor.Conclusion: MiR-624-5p could add to the cellular resistance to cisplatin in OC in-vitro model, which indicated that it might help unveil the mystery of drug-resistance in clinical stage of ovarian cancer. Keywords: MiR-624-5p, resistance, cisplatin, PDGFRA/Stat3/PI3K, ovarian cancer

Download Full-text

Influence of Zika Virus in mechanisms related of cytotoxicity, cell adhesion, apoptosis and inflammatory markers on glioblastoma cells

10.21203/rs.3.rs-1161905/v1 ◽

2021 ◽

Author(s):

Daniel Marinowic ◽

Fabiana Spillari Viola ◽

Fernanda Majolo ◽

Gabriele Goulart Zanirati ◽

Pamella Nunes Azevedo ◽

...

Keyword(s):

Cell Migration ◽

Cell Adhesion ◽

Cell Viability ◽

Cell Line ◽

Cell Lines ◽

Zika Virus ◽

Adhesion Behavior ◽

Induction Of Apoptosis ◽

Cd73 Expression ◽

Potential Use

Abstract Glioblastoma (GBM) is one of the most common brain tumors in adults. Despite the presence of available treatments, it remains one of the most lethal and difficult tumors to treat such that most patients die within two years. Studies reported that infection with Zika virus (ZIKV) causes inhibition of cell proliferation as well as induction of apoptosis; moreover, these manifestations show a predilection for developing neuronal cells. In the present study, two GBM cell lines U-138 and U-251 were infected with ZIKV at multiplicities of infection (MOI) 0.1, 0,01 and 0.001 and tested for cell viability, cell migration, cell adhesion, induction of apoptosis, interleukin levels, and cell surface markers (CD14 and CD73). Our study demonstrated that the ZIKV infection promotes loss of cell viability and increased apoptosis potential. It was not evidenced changes in cell migration, however, the two glioblastoma cell lines displayed increased the cell adhesion behavior. There was small increase in the IL-4 level in the U-251 cell line after exposure to ZIKV, with no change in relation to INF-γ levels. Furthermore, we observed an increase in the percentage of cells expressing the CD14 surface marker in both cell lines and increased CD73 expression in the U-251 cell line. Our results suggest that ZIKV may be associated with decrease of cell viability and increased CD73 expression, enhanced adherence, as well as increased apoptosis rates. Further investigations are required to explore the potential use of ZIKV in the treatment of GBM.

Download Full-text

Targeting XIAP Via Degradation of MDM-2 By MX69 in Aggressive Lymphomas

Blood ◽

10.1182/blood-2018-99-118480 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 5379-5379

Author(s):

Sumera Khan ◽

Kyle Runckel ◽

Cory Mavis ◽

Matthew J. Barth ◽

Francisco J. Hernandez-Ilizaliturri

Keyword(s):

B Cell ◽

Cell Lines ◽

Cell Lymphoma ◽

Single Agent ◽

B Cell Lymphoma ◽

Parp Cleavage ◽

Synergistic Activity ◽

In Vitro Exposure ◽

Induction Of Apoptosis

Abstract Background: The addition of Rituximab to front-line therapy has improved clinical outcomes in diffuse large B-cell lymphoma (DLBCL), but it has also altered the biology of relapsed/refractory disease. To better understand the mechanisms responsible for Rituximab associated chemotherapy cross-resistance our group developed and characterized several Rituximab resistance cell lines (RRCL). We previously demonstrated using SiRNA interference, that X-linked inhibitor of apoptosis (XIAP) is critical for chemotherapy sensitivity and survival in RRCL. MX69, a dual inhibitor of Mdm2 and XIAP that indirectly downregulates XIAP, is undergoing pre-clinical testing. MX69 affects XIAP levels by its effects on the ubiquitination and degradation of endogenous MDM-2, resulting in decrease XIAP translation and activation of caspase 3, 7 and 9 as well as PARP cleavage leading to apoptosis of cancer cells. In our current work, we pharmacologically inhibited XIAP in lymphoma pre-clinical models using MX69. Materials and Methods: A panel of Burkitt's Lymphoma (BL, including RRCL), germinal center B-cell (GCB)-DLBCL (including RRCL), activated B-cell (ABC)-DLBCL, Mantle cell Lymphoma (MCL) and Pre-B cell Leukemia cell lines were exposed to MX69 as a single agent (0-80uM) over 24, 48, 72 hrs and IC50 concentrations were calculated for each cell line. Changes in Mdm2, p53, XIAP and PARP expressions were determined following MX69 exposure (at IC50 doses) for 24 hrs. Induction of apoptosis was evaluated by Annexin V/propidium iodine staining. Subsequently, cell lines were exposed to MX69 (0-80 uM), in combination with Doxorubicin (0-1uM), Cytarabine(0-50uM), Vincristine (0-10nM), Etoposide(0-50uM), Carboplatin (0-20uM), Ixazomib (0-1.5uM), Ibrutinib (0-20uM) and Venetoclax (0-10uM) for 48 hours. Cell viability was determined by Cell Titerglo. Coefficient of synergy was calculated using CalcuSyn. Results: In vitro, MX69 single agent exposure induced cell death in a dose and time-dependent manner in all cell lines tested. Western blotting studies confirmed downregulation of Mdm2, XIAP and changes in P53 and PARP, following in vitro exposure to MX69. Induction of apoptosis was observed by flow cytometry in all cell lines tested. The combination of MX69 with Doxorubicin, Cytarabine, Vincristine, Ixazomib, Carboplatin, Etoposide, Ibrutinib, and Venetoclax resulted in significant synergistic activity. The strongest CI of synergy was observed when cell lines were exposed to MX69 and Venetoclax, Ixazomib, Etoposide or Ibrutinib. Conclusion: Our data suggests that in vitro exposure of a wide variety of B-cell lymphoma cell lines (including BL, DLBCL, MCL or RRCL) to MX69 resulted in anti-tumor activity. Perhaps related to its anti-tumor effects, MX69 inhibited XIAP levels. These findings are similar to prior SiRNA XIAP knockdown experiments. Strong synergistic activity was observed when XIAP was combined with various chemotherapy agents and small molecules inhibitors (such as Venetoclax, ixazomib or ibrutinib). Ex vivo experiments using primary tumor cells isolated from lymphoma patients and lymphoma mouse models are been planned. Targeting Mdm2 and XIAP can be an attractive therapeutic strategy in patients with Rituximab-sensitive or -resistant B-cell lymphoma. Disclosures No relevant conflicts of interest to declare.

Download Full-text

Activity of Rituximab and Ofatumumab Against Mantle Cell Lymphoma (MCL) in Vitro in MCL Cell Lines and Ex Vivo in Tumor Cells Derived From Patient Tumor Samples

Blood ◽

10.1182/blood.v118.21.4972.4972 ◽

2011 ◽

Vol 118 (21) ◽

pp. 4972-4972

Author(s):

Matthew J. Barth ◽

Gopichand Pendurty ◽

Cory Mavis ◽

Natalie M Czuczman ◽

John Gibbs ◽

...

Keyword(s):

Cell Viability ◽

Cell Line ◽

Tumor Cells ◽

Cell Lines ◽

Research Funding ◽

Cell Lymphoma ◽

Clinical Investigations ◽

Mantle Cell ◽

Anti Cd20

Abstract Abstract 4972 Mantle cell lymphoma (MCL) is an aggressive form of non-Hodgkin lymphoma (NHL) that frequently presents with advanced stage disease. The addition of rituximab, a monoclonal anti-CD20 antibody, to high dose chemotherapy regimens often followed by stem cell transplant has improved outcomes, but survival still remains low at 3–5 years. Novel agents are needed to improve outcomes in MCL. Ofatumumab is a fully human anti-CD20 monoclonal antibody directed against a novel epitope on the CD20 antigen. Ofatumumab has been shown to be more potent than rituximab against B-NHL cells in pre-clinical investigations. Ofatumumab is FDA approved for the treatment of CLL that is fludarabine and alemtuzumab refractory or with bulky disease resistant to fludarabine and is being investigated in clinical trials in NHL. In order to characterize the activity of ofatumumab against MCL, we performed pre-clinical investigations into the activity of ofatumumab against MCL cell lines and primary MCL tumor cells derived from patient tumor samples (n=2). Antibody-dependant cellular cytotoxicity (ADCC) and complement dependent cytotoxicity (CDC) assays were performed in the MCL cell lines Mino, Jeko, Rec-1 and Z-138 to demonstrate sensitivity to rituximab and ofatumumab. Lymphoma cells were labeled with 51Cr prior to incubation with rituximab or ofatumumab at 10ug/mL plus human serum or effector cells (efector:target ratio of 20:1). 51Cr-release was measured and the percentage of lysis was calculated. Patient tumor cells were isolated from tumor biopsy samples by MACS sorting (negative selection). Patient tumor cells were incubated with ofatumumab or rituximab at 10ug/mL in the presence of human serum as a complement source. Cell viability was determined at 48 hours by CellTiterGlo assay. Means were compared using a t-test. Expression of CD20 and the complement inhibitory proteins (CIPs) CD55 and CD59 in MCL cell lines were determined by flow cytometry and compared to the rituximab-sensitive cell line Raji and the rituximab-resistant cell line Raji 4RH. Surface density of CD20, CD55 and CD59 were determined by Imagestream analysis. Western blot was performed to measure total CD20 protein expression. Ofatumumab induced significantly higher levels of cell lysis compared to rituximab in CDC assays of all MCL cell lines tested (Mino: 65.9% vs 0.5%; JeKo 43.9% vs 13.3%; REC-1 25.4% vs 4.7%; Z-138: 56.4% vs 0.65%; all p-values <0.05). The ADCC assays showed a similar degree of lysis with ofatumumab when compared to rituximab in all cell lines tested. In primary tumor cells, ofatumumab and rituximab demonstrated similar levels of decreased cell viability following 48 hours of antibody exposure. MCL cell lines demonstrated similar expression of surface and total CD20 when compared to the rituximab-sensitive B-NHL Raji cell line. CIP expression was increased in all MCL cell lines compared to Raji cells and was similar to the rituximab-resistant Raji 4RH cell line. Our data suggest ofatumumab is more potent than rituximab against MCL cells in vitro and retains CDC activity despite high expression levels of CIPs. This increased activity was not seen in patient tumor samples; however we were limited by the number of available patient samples. In vivo experiments investigating the activity of ofatumumab in a SCID mouse MCL xenograft model and investigations into the activity of ofatumumab in MCL cells in combination with cytotoxic agents and novel small molecule inhibitors are ongoing. Disclosures: Czuczman: Genmab: Consultancy, Honoraria, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Research Funding. Hernandez-Ilizaliturri:Genmab: Research Funding.

Download Full-text

Omipalisib (GSK458), a Novel Pan-PI3K/mTOR Inhibitor, Exhibits In Vitro Anti-Lymphoma Activity in Chemotherapy-Sensitive and -Resistant Models of Burkitt Lymphoma

Blood ◽

10.1182/blood.v128.22.5376.5376 ◽

2016 ◽

Vol 128 (22) ◽

pp. 5376-5376 ◽

Cited By ~ 2

Author(s):

Thomas Ippolito ◽

Greg Tang ◽

Cory Mavis ◽

Juan J Gu ◽

Francisco J. Hernandez-Ilizaliturri ◽

...

Keyword(s):

Cell Cycle ◽

Flow Cytometry ◽

Cell Line ◽

Cell Lines ◽

Western Blotting ◽

Propidium Iodide ◽

Annexin V ◽

Mtor Pathway ◽

Pathway Inhibition

Abstract Background: Despite significant gains achieved in the treatment of Burkitt lymphoma (BL), current multi-agent immunochemotherapeutic regimens lead to high rates of acute toxicity, and relapsed/refractory disease still represents a significant hurdle with survival expected in only about 20-30% of such patients. Novel targeted therapeutic approaches are necessary to reduce treatment related toxicity in the up-front setting and improve survival in the relapsed/refractory setting. Analyses of genomic abnormalities in BL have identified increased activation of the PI3K/Akt/mTOR pathway in BL, induced by tonic B-cell receptor signaling and increased expression of Myc induced microRNAs (miRs), as having a significant role in Burkitt lymphomagensis. Additionally, recent reports have implicated higher expression of PI3K activating, Myc induced miRs in pediatric patients with a higher risk of relapse. While focused targeting of PI3K with the PI3K-delta isoform specific inhibitor idelalisib has led to significant activity in indolent B-cell lymphomas, limited activity has been noted in the setting of more aggressive forms. A broader inhibition of both upstream and downstream components of the pathway may exhibit more significant anti-lymphoma activity. To this end, we investigated the in vitro effects of PI3K/Akt/mTOR pathway inhibition with the dual pan-PI3K/mTOR inhibitor Omipalisib (GSK458) in chemotherapy-sensitive and -resistant BL cell line models. Methods: The in vitro effect of omipalisib was investigated in the BL cell lines Raji, Raji 4RH (chemotherapy-rituximab resistant), Raji 8RH (rituximab resistant), Ramos, and Daudi. Cell viability following exposure to omipalisib alone and in combination with cytotoxic chemotherapeutic agents was analyzed using Cell-Titer Glo and Alamar Blue assays. Apoptosis was analyzed using western blotting for PARP and by flow cytometry with Annexin V-propidium iodide staining. Downstream targets in the PI3K/Akt/mTOR pathway were analyzed using western blotting. Cell cycle analysis was performed by flow cytometry using propidium iodide staining. Synergistic activity of combination exposures was determined by calculation of a combination index using CalcuSyn software. Results: In vitro exposure of BL cell lines to omipalisib in concentrations ranging from 0.05μM to 50μM for 24, 48 or 72 hours resulted in a dose and time dependent decrease in viable cells with significant activity noted at even low nM concentrations (48 hour IC50 values: Raji=1.2μM, Raji 4RH=0.02μM, Raji 8RH=1.9μM, Ramos=0.01μM, Daudi=0.01μM). Flow cytometry for Annexin V and propidium iodide, after 72 hours of single agent exposure to omipalisib, showed a marked induction of apoptosis in all cell lines. For example, at an omipalisib concentration of 200nM, the percentage of Annexin V positive cells were Raji=40.7%, Raji 4RH=4.4%, Raji 8RH=41.5%, Ramos=59.4% and Daudi=46.9%. Approximately ten-fold higher omipalisib concentrations were required to induce similar degrees of apoptosis in the chemotherapy resistant Raji 4RH cell line compared to chemotherapy sensitive cell lines. Western blotting for downstream targets of the PI3K/Akt/mTOR pathway, including S6 and GSK3Β, showed a reduction in phosphorylation after 30 minutes of exposure to omipalisib in all cell lines. Determination of cell cycle progression following exposure to omipalisib for 72 hours at concentrations ranging from 0.006μM to 25μM showed dose-dependent cell cycle arrest in G1 phase in all cell lines; however the chemotherapy resistant Raji 4RH cells arrested in G2/M at higher concentrations. When BL cells were exposed to omipalisib in combination with either doxorubicin or dexamethasone, synergistic anti-tumor activity was observed in all cell lines tested. Conclusion: Inhibition of PI3K and mTOR by the dual inhibitor omipalisib suppresses activation of the PI3K/Akt/mTOR pathway leading to impaired BL cell proliferation with G1 cell cycle arrest and induction of apoptosis in chemotherapy-sensitive and -resistant cell line models of BL. Inhibition of the PI3K/Akt/mTOR pathway with omipalisib also increases the in vitro response to cytotoxic chemotherapeutic agents. Our findings note the pre-clinical activity of PI3K/Akt/mTOR pathway inhibition in BL and highlight the relevance of pursuing PI3K/Akt/mTOR pathway inhibition as a potential therapeutic option in BL. Disclosures No relevant conflicts of interest to declare.

Download Full-text