The Combination Of 2-DG and Metformin Inhibits The mTORC1 Pathway and Suppresses Aggressive B Cell Lymphoma Growth and Survival

Abstract mTORC1 (mammalian target of rapamycin complex 1) plays a central role in integrating nutrient and growth factor inputs to control cell growth in all eukaryotes and is commonly deregulated in human cancers. Inhibition of mTORC1 is a promising strategy in lymphoma therapy. However, only a few drugs, such as rapamycin and its analogs (rapalogs), have been approved for treatment in a limited number of cancer types, due to their incomplete and nonspecific inhibition of mTORC1 as well as their limited effects toward the 4EBP1 pathway. 4EBP1 pathway regulates protein translation which is considered to be crucial in cancer cell survival and proliferation. In this study, we used the glycolysis inhibitor 2-deoxyglucose (2-DG) together with the mitochondrial respiratory inhibitor metformin to treat aggressive B cell lymphoma cells in vitro and in vivo. We found that the combined treatment inhibited mTORC1 and its major downstream targets, including 4EBP1. As a result, combined treatment significantly inhibited tumor cell growth and survival by the inhibition of 5’ cap-dependent translation involving lymphoma associated oncogenes such as MCL-1, BCL-XL and Cyclin D1. Moreover, the combination of 2-DG and metformin suppressed tumor growth in B cell lymphoma xenograft mouse models. Although the combined treatment dramatically decreased cellular ATP levels, mTORC1 inhibition was independent of AMPK activity but instead resulted from inhibitory effects on Rag-GTPases, which are upstream activators of mTORC1. Given that both 2-DG and metformin have been used in clinical diagnosis or treatment for decades, the combination of the two drugs hold promise as a new strategy to treat aggressive B cell lymphoma. Disclosures: No relevant conflicts of interest to declare.

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Prediction and Optimization of the Therapeutic Effect of mTOR Inhibitors in Aggressive B-Cell Lymphomas

Blood ◽

10.1182/blood.v126.23.4441.4441 ◽

2015 ◽

Vol 126 (23) ◽

pp. 4441-4441

Author(s):

Chengfeng Bi ◽

Xiaoyan Zhang ◽

Zhang Xuan ◽

Wing C Chan ◽

Timothy McKeithan ◽

...

Keyword(s):

B Cell ◽

Conflicts Of Interest ◽

Cell Lymphoma ◽

Mtor Inhibitors ◽

B Cell Lymphoma ◽

Mechanism Study ◽

B Cell Lymphomas ◽

Lymphoma Cells ◽

Induced Apoptosis ◽

Aggressive B Cell Lymphoma

Abstract Mechanistic target of rapamycin complex 1 (mTORC1) is a central integrator of nutrient and growth factor inputs that controls cell growth in all eukaryotes. Rapamycin and its analogs (rapalogs) have been approved for the treatment of relapsed mantle cell lymphoma. A large proportion of aggressive B-cell lymphoma patients, however, respond poorly to rapalogs. The second generation of mTOR inhibitors function as ATP-competitive inhibitors (TORi), directly targeting the mTOR catalytic site. TORis have been proven to be more effective than rapalogs in cancer treatment. However, the mechanism underlying the cytotoxic effect of TORis in aggressive B-cell lymphomas remains unclear. In this study, we demonstrated that TORi-induced apoptosis is predominantly dependent on loss of mTORC1-mediated 4EBP phosphorylation. Knocking out Rictor, a key component of mTORC2, or inhibiting p70S6K has little effect on TORi-induced apoptosis. In contrast, increasing the EIF4E:4EBP ratio by either overexpressing EIF4E or knocking out 4EBP1/2 protected lymphoma cells from TORi-induced cytotoxicity. Furthermore, down-regulation of MCL1 and BCL-XL expression plays an important role in TORi-induced apoptosis whereas BCL-2, in cells with high expression, confers resistance to TORi treatment. Based on the mechanism study, we demonstrated that BH3 profiling, primarily NOXA and HRK stimulation, can effectively predict the cytotoxicity of the TORi in lymphoma cells. Also, in combination with pro-apoptotic drugs, especially BCL-2 inhibitors, the TORi exerted powerful anti-tumor effects both in vitro and in vivo. Taken together, this study provides mechanistic insight in TORi treatment in aggressive B-cell lymphoma and identified a mean to predict and improve its effectiveness clinically. Disclosures No relevant conflicts of interest to declare.

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An Effective Salvage Treatment Using Rituximab, Ifosfamide, Etoposide, Cytarabine, and Dexamethasone (R-IVAD) for Patients with Relapsed or Refractory Aggressive B-Cell Lymphoma

Blood ◽

10.1182/blood.v116.21.1759.1759 ◽

2010 ◽

Vol 116 (21) ◽

pp. 1759-1759

Author(s):

Katsuhiro Miura ◽

Kazuhiro Takei ◽

Sumiko Kobayashi ◽

Yujin Kobayashi ◽

Toshitake Tanaka ◽

...

Keyword(s):

Stem Cell ◽

B Cell ◽

Conflicts Of Interest ◽

Cell Lymphoma ◽

Performance Status ◽

B Cell Lymphoma ◽

Complete Response ◽

High Dose ◽

Salvage Regimen ◽

Aggressive B Cell Lymphoma

Abstract Abstract 1759 Background The prognosis of patients with relapsed or refractory aggressive B-cell lymphoma after the conventional first line chemotherapy is still disappointing. Although several rituximab combined salvage regimens were reported, the optimal treatment has not yet been established. We therefore evaluated the efficacy and toxicity of a non-anthracycline based salvage regimen, consisting of rituximab, ifosfamide, etoposide, cytarabine and dexamethasone (R-IVAD) in patients with relapsed or refractory aggressive B-cell lymphoma. Patients and methods Patients with relapsed or refractory CD20-positive diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma grade 3 (FL G3) were consecutively enrolled in this treatment. R-IVAD consisted of rituximab (375 mg/m2 on day -2), ifosfamide (1500 mg/m2 on day 1–5), etoposide (150 mg/m2 on day 1–3), cytarabine (100 mg/m2 on day 1–3) and dexamethasone (40 mg/body on day 1–3). Treatment was given every 3 weeks up to a total of 3 courses with support of granulocyte colony stimulating factor. For responders under 65 years old with good performance status (PS), we planed peripheral stem cell collection after the third cycle of R-IVAD and consolidating high-dose chemotherapy (HDC) with cycrophosphamide (60 mg/kg on day -7,-6), etoposide (500 mg/m2 on day -6, -5, -4) and ranimustine (250 mg/m2 on day -3, -2) followed by autologous stem cell transplantation (ASCT). Results Thirty-two patients (25 DLBCL and 7 FL G3) with a median age of 64 years old (range 38–79) participated in this study and received an average of 2.6 cycles of R-IVAD. There were 21 relapsed and 11 primary refractory patients. The overall response (OR) and the complete response (CR) rate were 72% and 56% respectively. The OR rate of relapsed patients was significantly higher than that of primary refractory patients (86% vs. 45%, p=0.035). With a median 16 months (range 2–99) of follow up, the 2-year overall survival (OS) and the event-free survival (EFS) for all patients were 55% and 36% respectively. Of the 11 eligible patients, 10 successfully proceeded to HDC/ASCT with an average of 5.5 × 106/kg of harvested CD34-positive cells, resulting in the 2-year OS of 90%. No treatment related death was observed during the investigation. Multivariate analysis revealed that the age > 60 years, PS ≥ 2, extranodal sites ≥ 2, and primary refractory disease were independently associated with worse survival. Conclusion R-IVAD regimen, which efficiently mobilizes peripheral stem cells, is a safe and efficacious alternative for patients with relapsed or refractory aggressive B-cell lymphoma. Disclosures: No relevant conflicts of interest to declare.

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Rituximab Is Associated with Prolonged Immunoglobulin Deficiency In Newly Diagnosed Patients with Aggressive B-Cell Lymphoma Receiving Immunochemotherapy

Blood ◽

10.1182/blood.v116.21.2881.2881 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2881-2881 ◽

Cited By ~ 1

Author(s):

Kieron Dunleavy ◽

Benjamin L.W. Reiter ◽

Cliona M. Grant ◽

Margaret Shovlin ◽

George W. Wright ◽

...

Keyword(s):

B Cell ◽

Conflicts Of Interest ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

P Values ◽

Delayed Effects ◽

Time Points ◽

Immunoglobulin Deficiency ◽

Immunoglobulin Levels ◽

Aggressive B Cell Lymphoma

Abstract Abstract 2881 While the delayed effects of rituximab on immune reconstitution are poorly understood, hypogammaglobulinemia has been reported in relapsed patients treated with rituximab. With the widespread use of rituximab, the risk of hypogammaglobulinemia and increased susceptibility to serious infections needs to be formally evaluated. Furthermore, the long-term benefit of rituximab, such as during maintenance schedules, needs to be weighed against potential immunodeficiency. We set out to investigate if rituximab was associated with prolonged hypogammaglobulinemia in previously untreated patients with aggressive B-cell lymphoma (diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma (BL)) receiving immunochemotherapy compared to chemotherapy alone. All patients received DA-EPOCH [dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin] with or without rituximab 375 mg/m2 per cycle for 6–8 cycles. We measured sequential IgA, IgG and IgM immunoglobulin levels pre-treatment, at the end of treatment and at 6 and 12 months after treatment. We included samples from 99 patients: 81 received DA-EPOCH-R and 18 received DA-EPOCH alone. Characteristics were similar among patients who received DA-EPOCH-R or chemotherapy alone: male sex 49% v 44%; median age 39 years (18 – 85) v 46 years (20-64); histology DLBCL in 85% v 78% and BL in 15% v 22%, respectively. All patients were HIV negative and in remission at the time of the analysis. We first looked at the effect of chemotherapy alone (DA-EPOCH) on immunoglobulin levels and demonstrated that it induced significant reductions in immunoglobulins by the end of therapy: signed rank p-values were 1.5×10-5 for IgA, 1.5×10-5 for IgG and 1×10-4 for IgM. However, by 12 months after treatment, these changes from baseline had resolved and were no longer significant. Patients who received immunochemotherapy had very significant decrements in all immunoglobulins at the end of therapy – p=5.23×10-13 for IgA, 1.34×10-13 for IgG and 1.36×10-13 for IgM – and these remained significantly lower than baseline at 12 months following therapy – p=9.8×10-12 for IgA, 2.4×10-11 for IgG and 4.1×10-9 for IgM. Next, using Wilcox rank p-values, we compared the median immunoglobulin change (+or-) between the 2 groups at different time points. These were not significant at the end of therapy (p=0.17 for IgA, 0.059 for IgG and 0.97 for IgM) but highly significant for IgA (0.024) and IgG (0.0002) at 12 months following treatment, reflecting persistent immunoglobulin decrements in patients who received rituximab. Next, in patients who had normal immunoglobulin levels at baseline, we compared the proportion in both groups who maintained normal levels at several time points following therapy and this is represented in the chart below. This study, for the first time, demonstrates that in previously untreated patients with aggressive B-cell lymphoma, chemotherapy alone is associated with significant immunoglobulin decrements but these are short-lived and all patients recover normal immunoglobulins by 12 months after therapy. In contrast, immunochemotherapy with rituximab is associated with more severe decrements and prolonged immunoglobulin deficiency that lead to clinically significant reductions, even at 12 months following completion of therapy. Disclosures: No relevant conflicts of interest to declare.

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Chemo-Resistance in Diffuse Large Cell Lymphoma: Novel Drug Combinations Targeting NFAT/NF-Kb Growth/Survival/Chemo-Resistance Signaling Pathways in Validated Novel Experimental Systems

Blood ◽

10.1182/blood.v118.21.1428.1428 ◽

2011 ◽

Vol 118 (21) ◽

pp. 1428-1428

Author(s):

Lan V Pham ◽

Archito T. Tamayo ◽

Changping Li ◽

John Lee ◽

Luis Fayad ◽

...

Keyword(s):

Transcription Factor ◽

Cell Growth ◽

B Cell ◽

Cell Lines ◽

Conflicts Of Interest ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

Drug Combinations ◽

Synergistic Activity ◽

Novel Drug

Abstract Abstract 1428 Acquired chemo-resistance (ACR) is currently the most important cause of treatment failure and early mortality in DLBCL, arguably the most important unmet need in lymphoma therapy today. Diffuse Large B cell Lymphoma (DLBCL), the most common human lymphoma, comprises a genetically and clinically diverse group of aggressive B cell non-Hodgkin lymphomas (NHL-B), among a small group of important human cancers increasing in incidence in the US over the last four decades. NHL-B are the fifth most common cancers in the USA (>62,000 new cases/20,000 deaths) expected in 2011. The molecular biologic and genetic basis of the patho-physiology of these important lymphoid tumors is still mostly unresolved. This is due primarily to the lack of valid patho-biologic experimental models allowing for identification of the key patho-physiologic molecular/genetic mechanisms involved in chemo-resistance, resulting in mostly unsuccessful empiric new drug salvage trials, rather than efficient drug-targeting key growth/survival/chemo-resistance (GSC) pathways essential for effective salvage therapies. We have been developing such novel translational experimental DLBCL systems (>25 DLBCL cell lines derived from relapsed DLBCL patients) and novel agents as the conceptual basis of this model. We have distinguished a set of cell lines that are more resistant to chemo-therapy and identified that the transcription factor p52 component of the alternative NF-kB pathway is highly expressed in DLBCL cell lines that show the highest chemo-resistance characteristics. Down-regulation of p52 sensitizes resistant cells to chemotherapy. This is of particular interest since previous studies have not as yet established definitive role(s) for the alternative NF-kB pathway, particularly p52, in chemo-resistance development. We have discovered that the second generation proteasome inhibitor, Carfilzomib can target the alternative NF-kB-p52 pathway by down-regulating the TNF-receptor family BAFF-R, resulting in lymphoma cell growth inhibition and apoptosis induction. NFATc1, another important multifunctional regulatory molecule (transcription factor (TF), chromatin remodeler, etc), that we have shown to be intrinsically involved with NF-kBs in most DLBCL, and whose involvement in DLBCL is becoming increasingly important on multiple levels, that was recently confirmed genetically, identifying NFATc1 expression as a candidate oncogene in ABC DLBCLs. We have also discovered that GSK3b, a key upstream natural inhibitor of NFATc1, is constitutively phosphorylated in DLBCL cells and can negatively regulate NFATc1 activation. The PKC beta II inhibitor Enzastaurin, affectively inhibits pGSK3b, leading to NFATc1 inactivation and inhibiting cell growth/survival in a broad range of DLBCL cell lines, both GCB and ABC subtypes, with IC: 50 values in the low uM ranges. Enzastaurin strongly synergizes with Carfilzomib to inhibit DLBCL cell growth and induce apoptosis, particularly in chemo-resistant DLBCL cells. Carfilzomib alone enhances pGSK3b and NFATc1 activation, while Enzastaurin abolishes CFZ-induced pGSK3b and NFATc1, suggesting a mechanism for the synergistic activity of the drugs. Novel drug combinations with agents that target multiple growth, survival, and chemo-resistance pathways, such as Carfilzomib and Enzastaurin, represent promising, emerging therapeutic options for reversing chemo-resistance in relapsed/refractory DLBCL patients. Disclosures: No relevant conflicts of interest to declare.

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