sirolimus and Lymphoma--Large-B-Cell--Diffuse

Satisfactory treatment of relapsed/refractory diffuse large B-cell lymphoma (DLBCL) is not currently available and novel therapies are needed. mTOR is an intracellular kinase that is part of an aberrantly activated pathway in DLBCL. Preclinical studies in DLBCL cell lines demonstrated that everolimus, an oral selective mTOR inhibitor, induces cell cycle arrest and is synergistic with rituximab. Phase I studies indicated 10 mg daily to be the best dosing of everolimus in DLBCL. A large Phase II study in relapsed/refractory DLBCL confirmed the substantial activity (overall response rate: 30%) and good tolerability of everolimus in DLBCL, with thrombocytopenia being the main toxicity. The combination of everolimus and rituximab showed encouraging results (objective response rate: 38%; complete response: 13%), without increasing toxicity. Combination studies of everolimus with novel agents or with immunochemotherapy are underway.

Topics: Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Drug Evaluation, Preclinical; Everolimus; Humans; Lymphoma, Large B-Cell, Diffuse; Protein Kinase Inhibitors; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Murine-Derived; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Bendamustine Hydrochloride; Clinical Trials as Topic; Cyclophosphamide; Doxorubicin; Gene Targeting; Hematopoietic Stem Cell Transplantation; Humans; Indoles; Lymphoma, Follicular; Lymphoma, Large B-Cell, Diffuse; Nitrogen Mustard Compounds; Prednisone; Prognosis; Purine Nucleosides; Pyrimidinones; Risk; Rituximab; Salvage Therapy; Sirolimus; Transplantation, Autologous; Vincristine

The current standard treatment of patients with relapsed or refractory diffuse large cell B-Cell lymphoma (DLBCL) primarily consists of intensified salvage therapy and, if the disease is chemo-sensitive, high dose therapy followed with autologous stem cell transplantation. In the rituximab era however, this treatment approach has shown only limited benefit. In particular, patients relapsing after rituximab-containing primary treatment have an adverse prognosis, especially if this occurs within the first year after therapy or if the disease is primarily refractory. Therefore there is an ultimate need for improved salvage treatment approaches.. The STORM study is a prospective, multicentre phase I/II study to evaluate the safety, feasibility and activity of salvage therapy consisting of the mTOR inhibitor temsirolimus added to the standard therapy rituximab and DHAP for the treatment of patients with relapsed or refractory DLBCL. The primary objective of the phase I of the trial is to establish the maximum tolerated dose (MTD) of temsirolimus in combination with rituximab and DHAP. The secondary objective is to demonstrate that stem cells can be mobilized during this regimen in patients scheduled to proceed to high dose therapy. In phase II, the previously established maximum tolerated dose of temsirolimus will be used. The primary objective is to evaluate the overall response rate (ORR) in patients with relapsed DLBCL. The secondary objective is to evaluate progression free survival (PFS), overall survival (OS) and toxicity. The study will be accompanied by an analysis of lymphoma subtypes determined by gene expression analysis (GEP).. The STORM trial evaluates the safety, feasibility and activity of salvage therapy consisting of the mTOR inhibitor temsirolimus added to standard therapy of rituximab and DHAP for the treatment of patients with relapsed or refractory DLBCL. It also might identify predictive markers for this treatment modality.. ClinicalTrials.gov NCT01653067.

Topics: Adult; Antibodies, Monoclonal, Murine-Derived; Antineoplastic Combined Chemotherapy Protocols; Cisplatin; Cytarabine; Dexamethasone; Disease-Free Survival; Feasibility Studies; Female; Humans; Lymphoma, Large B-Cell, Diffuse; Male; Maximum Tolerated Dose; Neoplasm Recurrence, Local; Research Design; Rituximab; Salvage Therapy; Sirolimus; TOR Serine-Threonine Kinases

Diffuse large B-cell lymphoma is an aggressive non-Hodgkin's lymphoma without a standard therapy for patients who relapse after or are not eligible for salvage autologous stem cell transplantation. In vitro analysis of lymphoma cell lines has shown that everolimus can inhibit cell cycle progression in vitro and inhibitors of the mammalian target of rapamycin have already demonstrated single-agent activity in relapsed non-Hodgkin's lymphomas including diffuse large B-cell lymphoma, validating mammalian target of rapamycin as a viable therapeutic target. We performed an open label phase II study of everolimus, an inhibitor of mammalian target of rapamycin, in combination with rituximab to examine efficacy and tolerability in patients with relapsed/refractory diffuse large B-cell lymphoma. Eligible patients were treated with everolimus 10 mg by mouth once daily on days 1-28 of a 28-day cycle with rituximab administered weekly during cycle one and then on day one of subsequent cycles. Patients were treated for a total of 12 cycles or until disease progression. The primary end-point was objective response rate, with secondary end-points being toxicity, progression-free survival, duration of response, and overall survival. Twenty-six patients (24 evaluable) were enrolled and had an overall response rate of 38% [90% CI (21%-56%)] with three complete responses and six partial responses among these 24 patients. The median duration of response among responders was 8.1 months. At a median follow-up of 12 months, the overall survival rate was 37% [90% CI (20%-54%)]. The most common grade 3 to 4 toxicities were neutropenia, anemia, and thrombocytopenia. In conclusion, everolimus in combination with rituximab is well tolerated and demonstrates activity in relapsed diffuse large B-cell lymphoma. Further studies of this combination are warranted.

Topics: Administration, Oral; Adult; Aged; Aged, 80 and over; Anemia; Antibodies, Monoclonal, Murine-Derived; Antineoplastic Combined Chemotherapy Protocols; Disease-Free Survival; Drug Administration Schedule; Everolimus; Fatigue; Female; Humans; Lymphoma, Large B-Cell, Diffuse; Male; Middle Aged; Neutropenia; Remission Induction; Rituximab; Sirolimus; Treatment Outcome

Despite high initial remission rates, most lymphomas relapse and require further therapy. The mammalian target of rapamycin (mTOR) pathway is a validated target in mantle cell lymphoma, but has not been extensively evaluated in other lymphomas.. We performed a phase II trial of single-agent temsirolimus 25-mg weekly in patients with relapsed aggressive and indolent lymphomas. The primary objective was overall and complete response rate. Patients were stratified by histology: group A (diffuse large B-cell lymphoma, transformed follicular lymphoma), group B (follicular lymphoma), and group C (chronic lymphocytic leukemia/small lymphocytic lymphoma, and other indolent lymphomas).. Eighty-nine patients were treated, with outcome strongly dependent on histology. Group A had an overall and complete response rate of 28.1% and 12.5%, respectively, and median progression-free survival (PFS) of 2.6 months and median overall survival (OS) of 7.2 months. Group B had overall and complete response rates of 53.8% and 25.6%, respectively, and median PFS of 12.7 months; median OS has not yet been reached. Group C had a partial response rate of 11% with no complete responders. Toxicity was mainly mild and/or reversible myelosuppression and mucositis; however, four patients developed pneumonitis.. Single-agent temsirolimus has significant activity in both diffuse large B-cell lymphoma and follicular lymphoma, although the durability of responses and PFS are longer for patients with follicular lymphoma. This is the first report of substantial activity of temsirolimus in lymphomas other than mantle cell lymphoma, and supports further evaluation of mTOR as a target in these diseases.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Bone Marrow; Chicago; Disease-Free Survival; Female; Humans; Intracellular Signaling Peptides and Proteins; Kaplan-Meier Estimate; Leukemia, Lymphocytic, Chronic, B-Cell; Lymphoma, Follicular; Lymphoma, Large B-Cell, Diffuse; Lymphoma, Mantle-Cell; Lymphoma, Non-Hodgkin; Male; Middle Aged; Mucositis; Pneumonia; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Remission Induction; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

Topics: Allografts; Female; Fissure in Ano; Humans; Lymphoma, Large B-Cell, Diffuse; Middle Aged; Sirolimus; Stem Cell Transplantation

The PI3K/Akt/mTOR pathway is activated in a variety of human tumors including B-cell non-Hodgkin lymphoma (B-NHL). Targeting this pathway has been validated in solid and hematological tumors. In the present study, we demonstrated that PF-04691502, a novel PI3K/mTOR inhibitor has potent activity in a panel of aggressive B-NHL cell lines including diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL). MTS analysis showed that PF-04691502 effectively inhibited cell proliferation with IC50 values ranging from 0.12 to 0.55 µM. Cells treated with PF-04691502 exhibited decreased phosphorylation of Akt and S6 ribosomal protein confirming the mechanism of action of a PI3K/mTOR inhibitor. Also, treatment of B-NHL cell lines with PF-04691502 induced apoptosis in a dose- and time-dependent manner. Moreover, PF-04691502 significantly induced G1 cell cycle arrest associated with a decrease in cyclin D1 which contributed to suppression of cell proliferation. Finally, rituximab enhanced apoptosis induced by PF-04691502. Taken together, our findings provide for the first time that PF-04691502 inhibits the constitutively activated PI3K/mTOR pathway in aggressive B-cell NHL cell lines associated with inhibition of cell cycle progression, cell proliferation and promotion of apoptosis. These findings suggest that PF-04691502 is a novel therapeutic strategy in aggressive B-cell NHL and warrants early phase clinical trial evaluation with and without rituximab.

Topics: Apoptosis; B-Lymphocytes; Cell Line, Tumor; Cell Proliferation; G1 Phase Cell Cycle Checkpoints; Humans; Lymphoma, Large B-Cell, Diffuse; Lymphoma, Mantle-Cell; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Pyridones; Pyrimidines; Rituximab; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Topics: Antibodies, Monoclonal, Murine-Derived; Antineoplastic Combined Chemotherapy Protocols; Carcinoma, Squamous Cell; Cyclophosphamide; Doxorubicin; Female; Humans; Immunosuppressive Agents; Kidney Transplantation; Lymphoma, Large B-Cell, Diffuse; Middle Aged; Neoplasms, Multiple Primary; Postoperative Complications; Prednisone; Remission Induction; Rituximab; Sirolimus; Skin Diseases; Skin Neoplasms; Vincristine; Warts

Lately, mTOR inhibitors have gained clinical relevance in malignant lymphoma. Still, rapamycin derivatives may activate a pro-survival feedback loop through PI3K-Akt. In this current study, temsirolimus effectively reduced cell growth in GCB and ABC diffuse large cell B-cell lymphoma (GCB=30-66%, ABC=45-57%). Combination treatment with the PI3K-δ inhibitor idelalisib additively effected ABC and GCB lymphoma (GCB=16-38%, ABC=25-50%). Since Bruton's Tyrosine Kinase (BTK) plays a significant role for the survival of ABC lymphoma, this study also combined the BTK inhibitor ibrutinib with temsirolimus, which resulted in additive cell growth reduction (ibrutinib 50%, temsirolimus 44%, combination 25%) in ABC lymphoma. In contrast, bortezomib, which has been shown previously to be efficient in ABC lymphoma, revealed an antagonistic effect with temsirolimus in some GCB lymphoma (temsirolimus 53%, temsirolimus+bortezomib 63%). Western blot analysis identified the increase of phosphorylated pro-survival kinases Akt and PDK as a possible underlying mechanism of this interaction.

Topics: Adenine; Antineoplastic Agents; Bortezomib; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Drug Antagonism; Drug Synergism; Humans; Lymphoma, Large B-Cell, Diffuse; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Piperidines; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Purines; Pyrazoles; Pyrimidines; Quinazolinones; Receptors, Antigen, B-Cell; Signal Transduction; Sirolimus

Abstract We evaluated the efficacy of the anti-CD20 monoclonal antibody rituximab in combination with the mammalian target of rapamycin (mTOR) inhibitor everolimus for treating diffuse large B-cell lymphoma (DLBCL). The combination of rituximab and everolimus was more effective for inhibiting cell growth compared with single-agent therapy. An increase in G0/G1 cell cycle arrest and an increased population of cells in apoptosis were observed in the combination treatment group. The addition of rituximab reduced the overexpression of p-AKT caused by the negative feedback loop of everolimus and had an enhanced effect on inhibition of mTOR signaling, thus providing a rationale for this synergistic effect. Furthermore, combination treatment was also more effective than treatment with either agent alone for inhibiting the growth of DLBCL xenografts. Our study provides preclinical evidence and a theoretical basis for combination therapy with rituximab and everolimus in DLBCL.

Topics: Animals; Antibodies, Monoclonal, Murine-Derived; Antineoplastic Agents; Apoptosis; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Drug Synergism; Everolimus; Humans; Lymphoma, Large B-Cell, Diffuse; Mice; Mice, Nude; Rituximab; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tumor Burden; Xenograft Model Antitumor Assays

Neoplastic processes, tumor growth, and tumor cell proliferation and survival are often due to the altered activation of different signaling pathways. The increased activity of PI3K/AKT/mTOR signaling has been shown to be an important regulator of tumor growth in several solid tumors and in mantle cell lymphomas. The active form of mTOR kinase (mammalian target of rapamycin) is a key signaling molecule, and it exists in two different complexes, mTORC1 and mTORC2. In the present work, mTOR activity was investigated in different lymphoma types, in parallel with clinical data. We also examined in Hodgkin lymphomas (HL) the role of mTOR activity in survival mechanisms such as antiapoptotic protein expression and alterations in the microenvironment. We determined which lymphoma types display characteristic high mTOR activity in our TMA (tissue microarray) study. We observed that mTOR activity is increased in mitotic lymphoid cells compared to interphasic cells. The number of diffuse large B cell lymphoma (DLBCL) and HL cases was extended in a further set of TMA. We observed significantly higher mTOR activity in the non-centrum germinativum derived subtype of DLBCL than in the centrum germinativum derived subtype, which was a prognostic marker; 63% of mTOR active cases showed Rictor overexpression, indicating mTORC2 activity. High mTOR activity was also established in 92% of HL cases, which was linked to mTORC1. This finding was not a prognostic marker, however, it can be useful in targeted therapy. We observed the overexpression of the antiapoptotic protein BCL-xL and NFκB-p50 in the majority of mTOR active HLs. HLs showed high numbers of regulatory T cells in the microenvironment and high expression of galectin-1 in tumor cells and in the extracellular matrix, when compared to reactive lymph nodes. We confirmed that mTOR inhibition had significant antiproliferative and antiapoptotic effects in lymphoma cell lines and in lymphoma xenografts (HL, DLBCL, Burkitt lymphoma). We also showed that rapamycin was able to augment the effect of chemotherapeutic agents and TGF-β. Taken together, mTOR activity may be a potential therapeutic target in different lymphoma types. However, patient and inhibitor selection criteria must be carefully considered. The combination of mTOR inhibitors with other agents will probably offer the highest efficiency for achieving the best clinical response, and may also allow dose reduction in order to decrease late treatment toxicity in th. A neopláziás folyamatok kialakulása, a daganat növekedése, a daganatsejtek proliferációja és túlélése hátterében gyakran különbözõ jelutak magváltozott aktivitása áll. A PI3K/AKT/mTOR jelút fokozott aktivitása szolid daganatokban és köpenysejtes lymphomákban a daganatkialakulás és -növekedés fontos szabályozója. Az aktív mTOR (mammalian target of rapamycin) kináz két komplex (mTORC1, mTORC2) meghatározó eleme. Az mTOR-aktivitás szerepét vizsgáltuk különbözõ humán lymphomákban, összefüggéseket keresve a betegek klinikai adataival. Hodgkin-lymphomákban (HL) tanulmányoztuk, hogy a magas mTOR-aktivitás milyen, a daganat túlélésében fontos folyamatokban vesz részt (antiapoptotikus mechanizmusok és mikrokörnyezeti változások). Meghatároztuk azokat a humán lymphomatípusokat, amelyekre magas mTOR-aktivitás jellemzõ. Kimutattuk, hogy a mitotikus lymphoid sejtek mTOR-aktivitása magasabb, mint a nem osztódó sejteké. Nagyobb esetszámot tartalmazó TMA-blokkokon (tissue microarray) tovább vizsgáltuk a diffúz nagy B-sejtes lymphoma (DLBCL) és a HL eseteket. Szignifikáns összefüggést mutattunk ki DLBCL-s betegek altípusmegoszlása (csíraközpont-eredetû és nem csíraközpont-eredetû DLBCL-ek) és az mTOR-aktivitás között. DLBCL-ban a fokozott mTOR-aktivitás negatív prognosztikus markernek bizonyult. A HL-ek 92%-a magas mTOR-aktivitást mutatott (mTORC1-hez köthetõ), ami prognosztikus faktorként nem, viszont terápiás célpontként felhasználható. A HL-ek mikrokörnyezetének vizsgálata szerint a regulátor T-sejtek mennyisége a mikrokörnyezetben, valamint a galektin-1-expresszió a tumorsejtekben és az extracelluláris mátrixban emelkedett. A magas mTOR-aktivitás és a galektin-1-expresszió között kapcsolatot találtunk in vitro kísérleteinkben, ahol az mTOR gátlása transzlációs szinten csökkentette a galektin-1-expressziót. Az mTOR-gátlás jelentõségét – proliferációgátló és apoptotikus hatását – humán lymphoma xenograftokban (HL, DLBCL, Burkitt-lymphoma) bizonyítottuk. In vitro kombinációs kezelésekben a rapamycin apoptotikus hatást fokozó szerepét igazoltuk. Munkánkban meghatároztuk azokat a lymphomatípusokat, amelyekben az mTOR-gátlás célzott terápiaként alkalmazható lehet. Eredményeink alapján annak meghatározása, hogy melyik komplexhez köthetõ az mTOR-aktivitás, nagyon fontos a megfelelõ mTOR-gátló (klasszikus vagy kettõs gátlók) kiválasztásában. A jövõben a magas mTOR-aktivitást mutató lymphomákban várhatóan kombinációs kezelésben az mTOR-gátlók használata hozzájárulhatna a jobb t

Topics: Animals; Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; bcl-X Protein; Burkitt Lymphoma; Cell Line; Drug Synergism; Galectin 1; Gene Expression Regulation, Neoplastic; Hodgkin Disease; Humans; Immunosuppressive Agents; Interphase; Lymphoma; Lymphoma, Large B-Cell, Diffuse; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Mitosis; Multiprotein Complexes; NF-kappa B p50 Subunit; Signal Transduction; Sirolimus; T-Lymphocytes, Regulatory; Tissue Array Analysis; TOR Serine-Threonine Kinases; Transforming Growth Factor beta; Up-Regulation; Xenograft Model Antitumor Assays

Diffuse large B cell lymphoma (DLBCL) represents the most common subtype of non-Hodgkin lymphoma and accounts for approximately 30% of newly diagnosed lymphoid neoplasms in Western countries, and 40-50% in China. A better understanding of the biology of DLBCL is needed for the development of potential therapeutic agents that target specific intracellular pathways. In this study, expression of the important components of the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway and their clinical significance were investigated in 73 DLBCL cases. The effect of rituximab alone or combined with the PI3K/AKT/mTOR pathway inhibitor rapamycin was further evaluated in the DLBCL cell lines. A total of 73 patients were identified, including 45 men and 28 women aged 18 to 78 years (median age 50 years). Of these patients, p-AKT was positive in 40 cases (54.8%), p-p70S6K in 34 cases (46.6%), and p-4E-BP1 in 33 cases (45.2%). Activation of the PI3K/AKT/mTOR pathway was related to poor disease outcome in DLBCL patients treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) but not in those treated with rituximab-CHOP. Rituximab combined with rapamycin synergically downregulated the PI3K/AKT/mTOR signaling pathway. Western blot analysis revealed a baseline activation status of the PI3K/AKT/mTOR pathway in DLBCL cell lines, with high levels of p-AKT, p-mTOR, in addition to downstream molecules p-p70S6K and p-4E-BP1. The results indicate that the PI3K/AKT/mTOR pathway is a potentially important signaling route and an unfavorable prognostic factor for DLBCL. Patients with PI3K/AKT/mTOR activation experience a more rapidly deteriorating clinical course with poor treatment response and decreased survival time. Addition of rituximab could downregulate PI3K/AKT/mTOR activation, reversing its negative effect on chemotherapy-treated patients. In addition, our results indicate that the combination of rituximab and inhibition of the activated PI3K/AKT/mTOR pathway could be a promising target for DLBCL therapeutic intervention in the future.

Topics: Adult; Aged; Antibodies, Monoclonal, Murine-Derived; Blotting, Western; Drug Synergism; Female; Humans; Immunohistochemistry; Lymphoma, Large B-Cell, Diffuse; Male; Middle Aged; Phosphatidylinositol 3-Kinase; Proto-Oncogene Proteins c-akt; Rituximab; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Young Adult

The aim of this study was to illustrate the mechanism of inhibiting the cell growth in diffuse large B-cell lymphoma by histone deacetylase inhibitor valproic acid (VPA) combined with mTOR inhibitor temsirolimus (TEM). MTT assay and Wright's stain were used to assess cell growth inhibition and to detect the cell morphological changes respectively. The cell apoptosis, cell cycle and cell autophagy were determined by flow cytometry. Ultrastructure changes were confirmed by electron microscopy. Protein changes were detected by Western blot. The results showed that both VPA and TEM alone inhibited cell proliferation and the effect was more obvious in the combination group. VPA combined with TEM induced cell arrest in G0/G1 phase and upregulated the expression of autophagy-related protein LC3, without cell apoptosis. Moreover, typical autophagosomes were observed, further confirming the presence of autophagy. Western blot showed the changes of proteins involved in autophagy signaling pathway. VPA decreased HDAC1 and HDAC3 expression and increased histone acetylation, suggesting that VPA also affected lymphoma cell proliferation through epigenetic modification. It is concluded that the combined treatment of VPA and TEM induces cell cycle arrest and cell autophagy, which provides a new clue for their clinical application in diffuse large B-cell lymphoma.

Topics: Autophagy; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Epigenesis, Genetic; Histone Deacetylase 1; Histone Deacetylases; Humans; Lymphoma, Large B-Cell, Diffuse; Microtubule-Associated Proteins; Sirolimus; Valproic Acid

Phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling is frequently dysregulated in diffuse large B cell lymphoma (DLBCL) including the favorable germinal centre B-cell (GCB) and the unfavorable activated B-cell (ABC) subtypes. mTOR promotes cap-dependent translation of proteins, like Mcl-1, through inhibitory phosphorylation of the eukaryotic translation initiation factor 4E binding protein 1 (4EBP1). Inhibition of mTOR by RAD001 reduces proliferation but fails to dephosphorylate 4EBP1 and to induce cell death in either DLBCL subtype. In contrast, concurrent inhibition of PI3K and mTOR with NVP-BEZ235 inhibits proliferation, dephosphorylates 4EBP1, and induces cells death, notably more pronounced in CGB cells. Small RNA interference identifies Mcl-1 as a crucial cell death mediator of both DLBCL subtypes. Inhibition of the PI3K/mTOR/4EBP1 by NVP-BEZ235 results in suppression of the cap-dependent translation initiation complex and concomitant downregulation of Mcl-1 in GCB cell lines. In ABC cell lines, this suppression is possibly compensated by NF-κB- or Pim kinase-mediated signaling.

Topics: Adaptor Proteins, Signal Transducing; Cell Cycle Checkpoints; Cell Cycle Proteins; Cell Death; Cell Line, Tumor; Everolimus; Gene Expression Regulation, Neoplastic; Humans; Imidazoles; Lymphoma, Large B-Cell, Diffuse; Myeloid Cell Leukemia Sequence 1 Protein; NF-kappa B; Phosphatidylinositol 3-Kinase; Phosphoinositide-3 Kinase Inhibitors; Phosphoproteins; Phosphorylation; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; Proto-Oncogene Proteins c-pim-1; Quinolines; Ribosomal Protein S6 Kinases, 70-kDa; RNA Interference; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The mTOR pathway is constitutively activated in diffuse large B-cell lymphoma (DLBCL). mTOR inhibitors have activity in DLBCL, although response rates remain low. We evaluated DLBCL cell lines with differential resistance to the mTOR inhibitor rapamycin: (i) to identify gene expression profile(s) (GEP) associated with resistance to rapamycin, (ii) to understand mechanisms of rapamycin resistance, and (iii) to identify compounds likely to synergize with mTOR inhibitor.. We sought to identify a GEP of mTOR inhibitor resistance by stratification of eight DLBCL cell lines with respect to response to rapamycin. Then, using pathway analysis and connectivity mapping, we sought targets likely accounting for this resistance and compounds likely to overcome it. We then evaluated two compounds thus identified for their potential to synergize with rapamycin in DLBCL and confirmed mechanisms of activity with standard immunoassays.. We identified a GEP capable of reliably distinguishing rapamycin-resistant from rapamycin-sensitive DLBCL cell lines. Pathway analysis identified Akt as central to the differentially expressed gene network. Connectivity mapping identified compounds targeting Akt as having a high likelihood of reversing the GEP associated with mTOR inhibitor resistance. Nelfinavir and MK-2206, chosen for their Akt-inhibitory properties, yielded synergistic inhibition of cell viability in combination with rapamycin in DLBCL cell lines, and potently inhibited phosphorylation of Akt and downstream targets of activated mTOR.. GEP identifies DLBCL subsets resistant to mTOR inhibitor therapy. Combined targeting of mTOR and Akt suppresses activation of key components of the Akt/mTOR pathway and results in synergistic cytotoxicity. These findings are readily adaptable to clinical trials.

Topics: Apoptosis; Biomarkers, Tumor; Blotting, Western; Cell Line, Tumor; Cell Proliferation; Drug Resistance, Neoplasm; Flow Cytometry; Fluorescent Antibody Technique; Gene Expression Profiling; Heterocyclic Compounds, 3-Ring; HIV Protease Inhibitors; Humans; Immunoenzyme Techniques; Lymphoma, Large B-Cell, Diffuse; Nelfinavir; Oligonucleotide Array Sequence Analysis; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Topics: Adult; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Cyclophosphamide; Doxorubicin; Drug Resistance, Neoplasm; Etoposide; Female; Humans; Lymphoma, Large B-Cell, Diffuse; Lymphoma, Non-Hodgkin; Prednisolone; Remission Induction; Sirolimus; Tongue Neoplasms; Treatment Failure; Treatment Outcome; Vincristine

The molecular mechanism(s) linking tumorigenesis and morphological alterations in the nucleolus are presently coming into focus. The nucleolus is the cellular organelle in which the formation of ribosomal subunits occurs. Ribosomal biogenesis occurs through the transcription of ribosomal RNA (rRNA), rRNA processing and production of ribosomal proteins. An error in any of these processes may lead to deregulated cellular translation, evident in multiple cancers and 'ribosomopathies'. Deregulated protein synthesis may be achieved through the overexpression of ribosomal proteins as seen in primary leukemic blasts with elevated levels of ribosomal proteins S11 and S14. In this study, we demonstrate that ribosomal protein S6 (RPS6) is highly expressed in primary diffuse large B-cell lymphoma (DLBCL) samples. Genetic modulation of RPS6 protein levels with specifically targeted short hairpin RNA (shRNA) lentiviruses led to a decrease in the actively proliferating population of cells compared with control shRNA. Low-dose rapamycin treatments have been shown to affect the translation of 5' terminal oligopyrimidine (5' TOP) tract mRNA, which encodes the translational machinery, implicating RPS6 in 5' TOP translation. Recently, it was shown that disruption of 40S ribosomal biogenesis through specific small inhibitory RNA knockdown of RPS6 defined RPS6 as a critical regulator of 5' TOP translation. For the first time, we show that RPS6 associates with multiple mRNAs containing a 5' TOP tract. These findings expand our understanding of the mechanism(s) involved in ribosomal biogenesis and deregulated protein synthesis in DLBCL.

Topics: Cell Line, Tumor; Cell Nucleolus; Endoribonucleases; Humans; Lymphoma, Large B-Cell, Diffuse; Phenotype; Poly(A)-Binding Proteins; Protein Biosynthesis; Ribosomal Protein S6; Ribosomes; RNA 5' Terminal Oligopyrimidine Sequence; RNA, Messenger; Sirolimus; T-Cell Intracellular Antigen-1

Topics: Aged; Aged, 80 and over; Carcinoma, Renal Cell; Enteritis; Everolimus; Female; Humans; Kidney Neoplasms; Lymphoma, Large B-Cell, Diffuse; Male; Middle Aged; Sirolimus; TOR Serine-Threonine Kinases

Topics: Azathioprine; Female; Humans; Immunosuppression Therapy; Liver Transplantation; Lymphoma, Large B-Cell, Diffuse; Sirolimus; Steroids; Tacrolimus; Young Adult

This study aimed to identify and evaluate molecular targets for the development of a novel combination chemotherapy to treat refractory and recurrent diffuse large B-cell lymphoma (DLBCL).. Lymphoma samples from 38 cases of primary and recurrent DLBCL were analyzed using real-time quantitative PCR of the RPS6KB1 and CDC2 genes, and immunohistochemistry for their gene products p70S6K/p85S6K and cdc2/cdk1. The Farage, Karpas422, Pfeiffer, and Toledo DLBCL cell lines were subsequently treated with rapamycin and UCN-01 alone or in combination. Cell proliferation, apoptosis, and cell cycle progression were analyzed after the drug treatment. In addition, the levels of several key protein kinases involved in the phosphoinositide 3'-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway, apoptosis, and cell cycle progression were analyzed in the presence and absence of the drugs.. Amplification of the RPS6KB1 and CDC2 genes was found in both primary and recurrent DLBCL. Moreover, the vast majority of these lymphomas (approximately 94%) were strongly positive for phospho-p70S6K and cdc2/cdk1 proteins. The combination of rapamycin and UCN-01 synergistically inhibited the DLBCL cell proliferation by inducing G1 arrest as well as apoptosis by suppressing the phosphorylation of p70S6K/p85S6K and CDC2 expression.. RPS6KB1 and CDC2 overexpression is common in DLBCL. Simultaneously targeting the RPS6KB1 and CDC2 products phospho-p70S6K/p85S6K and cdc2/cdk1 is very effective in inhibiting DLBCL proliferation and overcoming drug resistance. This work suggests that multilevel inhibition of the PI3K/Akt/mTOR pathway and double-block of cell cycle progression are effective strategies for DLBCL therapy.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Blotting, Western; CDC2 Protein Kinase; Cell Proliferation; Cyclin B; Cyclin-Dependent Kinases; Drug Synergism; Female; Flow Cytometry; G1 Phase; Gene Expression Profiling; Humans; Immunoenzyme Techniques; Lymphoma, Large B-Cell, Diffuse; Male; Middle Aged; Neoplasm Recurrence, Local; Oligonucleotide Array Sequence Analysis; Phosphatidylinositol 3-Kinases; Phosphorylation; Protein Kinases; Proto-Oncogene Proteins c-akt; Reverse Transcriptase Polymerase Chain Reaction; Ribosomal Protein S6 Kinases, 70-kDa; RNA, Messenger; Sirolimus; Staurosporine; TOR Serine-Threonine Kinases; Tumor Cells, Cultured

The mammalian target of rapamycin (mTOR) has emerged as an important therapeutic target for diffuse large B-cell lymphoma (DLBCL), as recent studies have demonstrated that 30% of relapsed patients respond to mTOR inhibitors. Why some lymphomas are resistant is incompletely understood. In the present study, we demonstrated that rapamycin inhibits mTORC1 in DLBCL lines and primary tumors but is minimally cytotoxic. Subsequent investigations revealed that rapamycin also activated eIF4E and the mTORC2 target Akt, suggesting a potential mechanism of rapamycin resistance. Furthermore, knockdown of the mTORC2 component rictor, but not the mTORC1 component raptor, inhibited rapamycin-induced Akt phosphorylation in lymphoma cells. Addition of the histone deacetylase inhibitor (HDI) LBH589 (LBH) overcame rapamycin resistance by blocking mTOR, thus preventing Akt activation. Further studies support the involvement of the protein phosphatase PP1 in LBH-mediated Akt dephosphorylation, which could be mimicked by knockdown of HDAC3. This is the first demonstration that a HDI such as LBH can overcome rapamycin resistance through a phosphatase that antagonizes mTORC2 activation. These results provide a mechanistic rationale for a clinical trial of a combination of HDI and mTOR inhibitors for DLBCL.

Topics: Antibiotics, Antineoplastic; Apoptosis; Blotting, Western; Cell Proliferation; Drug Resistance, Neoplasm; Drug Therapy, Combination; Enzyme-Linked Immunosorbent Assay; Eukaryotic Initiation Factor-4E; Flow Cytometry; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Hydroxamic Acids; Immunoenzyme Techniques; Immunoprecipitation; Indoles; Lymphoma, Large B-Cell, Diffuse; Mechanistic Target of Rapamycin Complex 1; Multiprotein Complexes; Panobinostat; Proteins; Proto-Oncogene Proteins c-akt; RNA, Small Interfering; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors; Tumor Cells, Cultured

ABT-263 is a potent, orally bioavailable inhibitor of the antiapoptotic Bcl-2 family members Bcl-2, Bcl-x(L), and Bcl-w, which is currently in phase I clinical trials. Previous work has shown that this compound has low nanomolar cell-killing activity in a variety of lymphoma and leukemia cell lines, many of which overexpress Bcl-2 through a variety of mechanisms. Rapamycin is a macrolide antibiotic that inhibits the mammalian target of rapamycin complex, leading to cell cycle arrest and inhibition of protein translation. Rapamycin (and its analogues) has shown activity in a variety of tumor cell lines primarily through induction of cell cycle arrest. Activity has also been shown clinically in mantle cell lymphoma and advanced renal cell carcinoma. Here, we show that treatment of the follicular lymphoma lines DoHH-2 and SuDHL-4 with 100 nmol/L rapamycin induces substantial G(0)-G(1) arrest. Addition of as little as 39 nmol/L ABT-263 to the rapamycin regimen induced a 3-fold increase in sub-G(0) cells. Combination of these agents also led to a significant increase in Annexin V staining over ABT-263 alone. In xenograft models of these tumors, rapamycin induced a largely cytostatic response in the DoHH-2 and SuDHL-4 models. Coadministration with ABT-263 induced significant tumor regression, with DoHH-2 and SuDHL-4 tumors showing 100% overall response rates. Apoptosis in these tumors was significantly enhanced by combination therapy as measured by staining with an antibody specific for cleaved caspase-3. These data suggest that combination of ABT-263 and rapamycin or its analogues represents a promising therapeutic strategy for the treatment of lymphoma.

Topics: Aniline Compounds; Animals; Antineoplastic Agents; Cell Cycle; Cell Death; Cell Line, Tumor; Drug Synergism; Humans; Immunohistochemistry; Lymphoma, Large B-Cell, Diffuse; Mice; Mice, SCID; Remission Induction; Sirolimus; Sulfonamides; Xenograft Model Antitumor Assays

Topics: Adult; Epstein-Barr Virus Infections; Humans; Immunosuppressive Agents; Kidney Transplantation; Lymphoma, Large B-Cell, Diffuse; Lymphoma, T-Cell; Lymphoproliferative Disorders; Male; Middle Aged; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) frequently carries the t(2;5)(p23;q35) resulting in aberrant expression of chimeric nucleophosmin-ALK. Previously, nucleophosmin-ALK has been shown to activate phosphatidylinositol 3-kinase (PI3K) and its downstream effector, the serine/threonine kinase AKT. In this study, we hypothesized that the mammalian target of rapamycin (mTOR) pathway, which functions downstream of AKT, mediates the oncogenic effects of activated PI3K/AKT in ALK+ ALCL. Here, we provide evidence that mTOR signaling phosphoproteins, including mTOR, eukaryotic initiation factor 4E-binding protein-1, p70S6K, and ribosomal protein S6, are highly phosphorylated in ALK+ ALCL cell lines and tumors. We also show that AKT activation contributes to mTOR phosphorylation, at least in part, as forced expression of constitutively active AKT by myristoylated AKT adenovirus results in increased phosphorylation of mTOR and its downstream effectors. Conversely, inhibition of AKT expression or activity results in decreased mTOR phosphorylation. In addition, pharmacologic inhibition of PI3K/AKT down-regulates the activation of the mTOR signaling pathway. We also show that inhibition of mTOR with rapamycin, as well as silencing mTOR gene product expression using mTOR-specific small interfering RNA, decreased phosphorylation of mTOR signaling proteins and induced cell cycle arrest and apoptosis in ALK+ ALCL cells. Cell cycle arrest was associated with modulation of G(1)-S-phase regulators, including the cyclin-dependent kinase inhibitors p21(waf1) and p27(kip1). Apoptosis following inhibition of mTOR expression or function was associated with down-regulation of antiapoptotic proteins, including c-FLIP, MCL-1, and BCL-2. These findings suggest that the mTOR pathway contributes to nucleophosmin-ALK/PI3K/AKT-mediated tumorigenesis and that inhibition of mTOR represents a potential therapeutic strategy in ALK+ ALCL.

Topics: Anaplastic Lymphoma Kinase; Apoptosis; Cell Cycle; Cell Line, Tumor; Cell Survival; Chromones; Down-Regulation; Enzyme Activation; Humans; Lymphoma, Large B-Cell, Diffuse; Morpholines; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Kinases; Protein-Tyrosine Kinases; Proto-Oncogene Proteins c-akt; Receptor Protein-Tyrosine Kinases; RNA, Small Interfering; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transfection

Diffuse large B-cell lymphoma (DLBCL) is a common lymphoma entity. Although a significant amount of DLBCL patients can be cured with modern chemotherapeutic regimens, a substantial proportion of patients die because of progressive disease. Therefore, new therapeutic strategies are clearly needed. Inhibitors of mTOR [mammalian target of rapamycin (Rap)] represent a new class of antiproliferative drugs with applications as immunosuppressive and anticancer agents. Extensive safety data exist on the mTOR inhibitor RAD001, which is already approved as an immunosuppressant in organ transplant recipients. Rap and RAD001 inhibited cell cycle progression in DLBCL cells by inducing a G1 arrest without inducing apoptosis. Phosphorylation of the main targets of mTOR, p70 s6 kinase and 4-EBP-1 was reduced in cells cultured in the presence of RAD001. Cell cycle arrest was accompanied by reduced phosphorylation of the retinoblastoma protein (RB) as well as reduced expression of cyclin D3 and A in all cell lines. Although the effect of the chemotherapeutic agent vincristine (vin) was not enhanced by RAD001, rituximab-induced cytotoxicity was augmented in the rituximab-sensitive cell lines. mTOR inhibition is a promising therapeutic strategy in DLBCL by inducing a G1 arrest and augments rituximab-induced cytotoxicity. Therefore, combination of these drugs might be an interesting new therapeutic approach in DLBCL patients.

Topics: Adaptor Proteins, Signal Transducing; Annexin A5; Antibodies, Monoclonal; Antibodies, Monoclonal, Murine-Derived; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Electrophoretic Mobility Shift Assay; Everolimus; Flow Cytometry; G1 Phase; Humans; Immunosuppressive Agents; In Situ Nick-End Labeling; Lymphoma, B-Cell; Lymphoma, Large B-Cell, Diffuse; Lymphoma, Non-Hodgkin; Oncogene Protein v-akt; Phosphoproteins; Phosphorylation; Protein Kinase Inhibitors; Protein Kinases; PTEN Phosphohydrolase; Retinoblastoma Protein; Ribosomal Protein S6 Kinases, 70-kDa; Rituximab; Sirolimus; TOR Serine-Threonine Kinases

Posttransplant lymphoproliferative disorders are a group of lymphoid proliferations and lymphomas that develop as a consequence of immunosuppression in recipients of solid organ or bone marrow allografts. We describe an unusual oral presentation of posttransplant Epstein-Barr virus-associated diffuse large B-cell lymphoma in a 45-year-old woman after pancreatic transplant.

Topics: Diagnosis, Differential; Epstein-Barr Virus Infections; Female; Herpesvirus 4, Human; Humans; Immunosuppressive Agents; Lymphoma, B-Cell; Lymphoma, Large B-Cell, Diffuse; Middle Aged; Mouth Neoplasms; Oral Ulcer; Pancreas Transplantation; RNA, Viral; Sirolimus; Tongue Diseases

The immunosuppressive macrolide rapamycin and its derivative everolimus (SDZ RAD, RAD) inhibit the mammalian target of rapamycin (mTOR) signaling pathway. In this study, we provide evidence that RAD has profound antiproliferative activity in vitro and in NOD/SCID mice in vivo against Hodgkin lymphoma (HL) and anaplastic large cell lymphoma (ALCL) cells. Moreover, we identified 2 molecular mechanisms that showed how RAD exerts antiproliferative effects in HL and ALCL cells. RAD down-regulated the truncated isoform of the transcription factor CCAAT enhancer binding protein beta (C/EBPbeta), which is known to disrupt terminal differentiation and induce a transformed phenotype. Furthermore, RAD inhibited constitutive nuclear factor kappaB (NF-kappaB) activity, which is a critical survival factor of HL cells. Pharmacologic inhibition of the mTOR pathway by RAD therefore interferes with essential proliferation and survival pathways in HL and ALCL cells and might serve as a novel treatment option.

Topics: Animals; CCAAT-Enhancer-Binding Protein-beta; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Down-Regulation; Everolimus; Hodgkin Disease; Humans; Lymphoma, Large B-Cell, Diffuse; Mice; Mice, Inbred NOD; Mice, SCID; NF-kappa B; Sirolimus; Transplantation, Heterologous