sirolimus and Lymphoma

Discovery of new treatments for lymphoma that prolong survival and are less toxic than currently available agents represents an urgent unmet need. We now have a better understanding of the molecular pathogenesis of lymphoma, such as aberrant signal transduction pathways, which have led to the discovery and development of targeted therapeutics. The ubiquitin-proteasome and the Akt/mammalian target of rapamycin (mTOR) pathways are examples of pathological mechanisms that are being targeted in drug development efforts. Bortezomib (a small molecule protease inhibitor) and the mTOR inhibitors temsirolimus, everolimus, and ridaforolimus are some of the targeted therapies currently being studied in the treatment of aggressive, relapsed/refractory lymphoma. This review will discuss the rationale for and summarize the reported findings of initial and ongoing investigations of mTOR inhibitors and other small molecule targeted therapies in the treatment of lymphoma.

Topics: Boronic Acids; Bortezomib; Everolimus; Humans; Lymphoma; Molecular Targeted Therapy; Pyrazines; Signal Transduction; Sirolimus; Survival Analysis

This review critically assesses recent research advances in elucidating the role of the mammalian target of rapamycin pathway in the pathogenesis of hematologic malignancies and the potential of targeting this signaling pathway to treat such malignancies.. Mammalian target of rapamycin is a highly conserved serine/threonine protein kinase that controls initiation of mRNA translation, cell cycle progression, and cellular proliferation. Recent dramatic advances in research into cellular signaling by mammalian target of rapamycin and its effectors, and better understanding of aberrant activation of mammalian target of rapamycin pathways in hematologic malignancies have stimulated considerable interest in the clinical development of inhibitors that target this pathway. Numerous clinical trials using mammalian target of rapamycin inhibitors are ongoing in various hematologic malignancies. Such trials are direct extensions of preclinical work establishing that inhibition of this pathway blocks cell proliferation and/or induces apoptotic cell death, both in vitro and in vivo.. The role of the mammalian target of rapamycin pathway in hematologic malignancies is of considerable interest with major clinical/translational relevance. Here, our understanding of the functional roles of the mammalian target of rapamycin pathway and its deregulation in hematologic malignancies are summarized and resulting clinical/translational efforts discussed.

Topics: Clinical Trials as Topic; Humans; Leukemia; Lymphoma; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR) kinase is positioned at the juncture of several pathways regulating cell growth and proliferation. It is the downstream effector of the oncogenic PI3K/Akt pathway and is a key regulator of translational initiation. Accumulating data support mTOR's role in lymphomagenesis, and its inhibition in preclinical models leads to lymphoma regression. The rationale for testing mTOR inhibitors in patients with lymphoma is evident, and early clinical data is promising. Along with the prototype of mTOR inhibitors, rapamycin, there are three mTOR inhibitors furthest along in development: temsirolimus, everolimus, and AP23573. These agents are emerging as well-tolerated drugs with encouraging preliminary activity. Here we review the rationale for testing mTOR inhibitors in lymphoma, the phase 1 trials influencing dose and schedule of mTOR inhibitors, and summarize the clinical results in obtained to date in patients with lymphoma.

Topics: Antineoplastic Agents; Everolimus; Humans; Lymphoma; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

Preclinical studies have shown augmented activity when combining Bruton tyrosine kinase inhibitors (BTKi) with inhibitors of mammalian target of rapamycin (mTOR) and immunomodulatory agents (IMiD). We conducted a phase 1, open-label study at five centers in USA to evaluate the safety of triplet BTKi/mTOR/IMiD therapy. Eligible patients were adults aged 18 years or older with relapsed/refractory CLL, B cell NHL, or Hodgkin lymphoma. Our dose escalation study used an accelerated titration design and moved sequentially from single agent BTKi (DTRMWXHS-12), doublet (DTRMWXHS-12 + everolimus), and then to triplet therapy (DTRMWXHS-12 + everolimus + pomalidomide). All drugs were dosed once daily on days 1-21 of each 28-day cycle. The primary goal was to establish the recommended phase 2 dose of the triplet combination. Between September 27, 2016, and July 24, 2019, a total of 32 patients with a median age of 70 years (range 46 to 94 years) were enrolled. No MTD was identified for monotherapy and the doublet combination. The MTD for the triplet combination was determined to be DTRMWXHS-12 200 mg + everolimus 5 mg + pomalidomide 2 mg. Responses across all studied cohorts were seen in 13 of 32 (41.9%). Combining DTRMWXHS-12 with everolimus and pomalidomide is tolerable and shows clinical activity. Additional trials could confirm benefit of this all-oral combination therapy for relapsed/refractory lymphomas.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Everolimus; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Lymphoma; Middle Aged; Neoplasm Recurrence, Local; Protein Kinase Inhibitors; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome; Tyrosine Kinase Inhibitors

The current standard of care for patients with Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) is high-dose conditioning followed by autologous stem cell transplantation (ASCT). For some patients (ie, those with highest-risk disease, insufficient stem cell numbers after mobilization, or bone marrow involvement) allogeneic hematopoietic cell transplantation (alloHCT) offers the potential for cure. However, the majority of patients undergoing alloHCT receive reduced-intensity conditioning as a preparative regimen, and studies assessing outcomes of patients after alloHCT with myeloablative conditioning are limited. In this retrospective study, we reviewed outcomes of 22 patients with recurrent and refractory NHL who underwent alloHCT with myeloablative BEAM conditioning and received tacrolimus/sirolimus as graft-versus-host disease (GVHD) prophylaxis at City of Hope between 2005 and 2018. With a median follow-up of 2.6 years (range, 1.0 to 11.2 years), the probabilities of 2-year overall survival and event-free survival were 58.3% (95% confidence interval [CI], 35.0% to 75.8%) and 45.5% (95% CI, 24.4% to 64.3%), respectively. The cumulative incidence of grade II to IV acute GVHD was 45.5% (95% CI, 23.8% to 64.9%), with only 1 patient developing grade IV acute GVHD. However, chronic GVHD was seen in 55% of the patients (n = 12). Of the 22 eligible patients, 2 had undergone previous ASCT and 2 had undergone previous alloHCT. Both patients with previous ASCT developed severe regimen-related toxicity. Patients who underwent alloHCT with chemorefractory disease had lower survival rates, with 1-year OS and EFS of 44.4% and 33.0%, respectively. In conclusion, alloHCT with a BEAM preparative regimen and tacrolimus/sirolimus-based GVHD should be considered as an alternative option for patients with highest-risk lymphoma whose outcomes are expectedly poor after ASCT.

Topics: Adolescent; Adult; Allografts; Antineoplastic Combined Chemotherapy Protocols; Carmustine; Cytarabine; Disease-Free Survival; Female; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Incidence; Lymphoma; Male; Melphalan; Middle Aged; Podophyllotoxin; Sirolimus; Survival Rate; Tacrolimus; Transplantation Conditioning

Inhibition of the mechanistic target of rapamycin (mTOR) pathway has clinical activity in lymphoma. The mTOR inhibitor sirolimus has been used in the prevention and treatment of graft-versus-host disease (GVHD) after allogeneic haematopoietic stem cell transplantation (HSCT). A retrospective study suggested that patients with lymphoma undergoing reduced intensity conditioning (RIC) HSCT who received sirolimus as part of their GVHD prophylaxis regimen had a lower rate of relapse. We therefore performed a multicentre randomized trial comparing tacrolimus, sirolimus and methotrexate to standard regimens in adult patients undergoing RIC HSCT for lymphoma in order to assess the possible benefit of sirolimus on HSCT outcome. 139 patients were randomized. There was no difference overall in 2-year overall survival, progression-free survival, relapse, non-relapse mortality or chronic GVHD. However, the sirolimus-containing arm had a significantly lower incidence of grade II-IV acute GVHD (9% vs. 25%, P = 0·015), which was more marked for unrelated donor grafts. In conclusion, the addition of sirolimus for GVHD prophylaxis in RIC HSCT is associated with no increased overall toxicity and a lower risk of acute GVHD, although it does not improve survival; this regimen is an acceptable option for GVHD prevention in RIC HSCT. This trial is registered at clinicaltrials.gov (NCT00928018).

Topics: Adolescent; Adult; Aged; Allografts; Female; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Lymphoma; Male; Methotrexate; Middle Aged; Sirolimus; Tacrolimus; Transplantation Conditioning

Many patients with lymphoma relapse after autologous stem cell transplantation (AutoSCT). These patients are often considered for allogeneic stem cell transplantation (AlloSCT) if remission can be achieved. If a tandem approach was organized, some cases of relapse might be prevented. We conducted a phase II trial of tandem AutoSCT followed by reduced-intensity conditioning (RIC) AlloSCT for patients with high-risk lymphoma. High-dose chemotherapy was given with busulfan, cyclophosphamide, and etoposide. AlloSCT was composed of RIC with busulfan/fludarabine and tacrolimus, sirolimus, and methotrexate as graft-versus-host disease (GVHD) prophylaxis. Donors were fully matched related or unrelated donors. AlloSCT was performed any time between 40 days and 6 months after AutoSCT. Forty-two patients were enrolled, and all patients underwent AutoSCT. RIC AlloSCT was performed in 29 patients. In the 29 patients who underwent tandem transplant, median time from AutoSCT to AlloSCT was 96 days (range, 48 to 169). The 6-month cumulative incidence of grades II to IV acute GVHD was 13.8% (90% confidence interval [CI], 5.3% to 26.3%). Cumulative incidence of chronic GVHD at 1 year was 37.9% (90% CI, 23.1% to 52.7%). Nonrelapse mortality at 2 years after AlloSCT was 11.1% (90% CI, 3.5% to 23.6%). At a median follow-up of 30 months (range, 17.1 to 51.5) for the entire group, the 2-year progression-free survival rate was 64% (90% CI, 50% to 75%) and the 2-year overall survival rate was 69% (90% CI, 43% to 85%). For the 29 patients who underwent tandem SCT, the 2-year progression-free survival rate was 72% (90% CI, 55% to 83%) and the 2-year OS rate was 89% (90% CI, 74% to 96%). Tandem AutoSCT-RIC AlloSCT appears to be safe and effective in patients with high-risk lymphoma. Prospective trials using such an approach in specific lymphoma subtypes are warranted.

Topics: Adult; Aged; Allografts; Antineoplastic Combined Chemotherapy Protocols; Autografts; Busulfan; Disease-Free Survival; Female; Follow-Up Studies; Graft vs Host Disease; Humans; Lymphoma; Male; Methotrexate; Middle Aged; Sirolimus; Stem Cell Transplantation; Survival Rate; Tacrolimus; Vidarabine

The study is a randomized phase II trial investigating graft-versus-host disease prophylaxis after non-myeloablative (90 mg/m(2) fludarabine and 2 Gy total body irradiation) human leukocyte antigen matched unrelated donor transplantation. Patients were randomized as follows: arm 1 - tacrolimus 180 days and mycophenolate mofetil 95 days (n=69); arm 2 - tacrolimus 150 days and mycophenolate mofetil 180 days (n=71); arm 3 - tacrolimus 150 days, mycophenolate mofetil 180 days and sirolimus 80 days (n=68). All patients had sustained engraftment. Grade II-IV acute graft-versus-host disease rates in the 3 arms were 64%, 48% and 47% at Day 150, respectively (arm 3 vs. arm 1 (hazard ratio 0.62; P=0.04). Owing to the decreased incidence of acute graft-versus-host disease, systemic steroid use was lower at Day 150 in arm 3 (32% vs. 55% in arm 1 and 49% in arm 2; overall P=0.009 by hazard ratio analysis). The Day 150 incidence of cytomegalovirus reactivation was lower in arm 3 (arm 1, 54%; arm 2, 47%; arm 3, 22%; overall P=0.002 by hazard ratio analysis). Non-relapse mortality was comparable in the three arms at two years (arm 1, 26%; arm 2, 23%; arm 3, 18%). Toxicity rates and other outcome measures were similar between the three arms. The addition of sirolimus to tacrolimus and mycophenolate mofetil is safe and associated with lower incidence of acute graft-versus-host disease and cytomegalovirus reactivation. (clinicaltrials.gov identifier: 00105001).

Topics: Adolescent; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Female; Follow-Up Studies; Graft Rejection; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Incidence; Leukemia; Lymphoma; Male; Middle Aged; Mycophenolic Acid; Recurrence; Sirolimus; Tacrolimus; Transplantation Chimera; Transplantation Conditioning; Transplantation, Homologous; Treatment Outcome; Unrelated Donors; Young Adult

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Bendamustine Hydrochloride; Boronic Acids; Bortezomib; Brentuximab Vedotin; Diphtheria Toxin; Drug Discovery; Everolimus; Humans; Hydroxamic Acids; Immunoconjugates; Indoles; Inotuzumab Ozogamicin; Interleukin-2; Lenalidomide; Lymphoma; Lymphoma, B-Cell; Nitrogen Mustard Compounds; Purine Nucleosides; Pyrazines; Pyrimidinones; Recombinant Fusion Proteins; Sirolimus; Thalidomide; Vorinostat

Changes in glucose and energy metabolism contribute to the altered phenotype of cancer cells and are the basis for positron emission tomography with. An FDG uptake assay was established and uptake of FDG by lymphoma cells was determined after incubation with inhibitors of the c-MYC and the PI3K signalling pathways that are known to be activated in lymphoma cells and able to regulate glucose metabolism. Inhibitors of MAPK signalling pathways whose role in altered metabolism is still unclear were also investigated. Expression of mRNAs of the glucose transporter 1 (GLUT1), hexokinase 2 (HK2), glucose-6-phosphatase (G6Pase) and lactate dehydrogenase A (LDHA) and of the glucose metabolism-regulating micro RNAs (miRNA) miR21, -23a, -133a, -133b, -138-1 and -143 was determined by RT-PCR. Cell viability was analysed by MTT assay.. Treatment with the c-MYC inhibitor 10058-F4 and inhibitors of the PI3K/mTOR pathway diminished uptake of FDG in all three cell lines, while inhibition of MAPK pathways had no effect on glucose uptake. Expression of glycolysis-related genes and miRNAs were diminished, although to a variable degree in the three cell lines. The c-MYC inhibitor, the PI3K inhibitor LY294002, the mTOR inhibitor Rapamycin and 2-DG all diminished the number of viable cells. Interestingly, in combination with 2-DG, the c-MYC inhibitor, LY294002 and the p38 MAPK inhibitor SB203580 had synergistic effects on cell viability in all three cell lines.. c-MYC- and PI3K/mTOR-inhibitors decreased viability of the lymphoma cells and led to decreased glucose uptake, expression of glycolysis-associated genes, and glucose metabolism-regulating miRNAs. Inhibition of HK by 2-DG reduced cell numbers as a single agent and synergistically with inhibitors of other intracellular pathways. Thus, targeted inhibition of the pathways investigated here could be a strategy to suppress the glycolytic phenotype of lymphoma cells and reduce proliferation.

Topics: Cell Line, Tumor; Cell Survival; Chromones; Fluorodeoxyglucose F18; Glucose; Glycolysis; Humans; Inhibitory Concentration 50; Lymphoma; Morpholines; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-myc; Sirolimus; Time Factors

We have previously found that ex vivo expanded human CD4

Topics: Adult; Aged; B-Lymphocytes; Blood Donors; CD4 Antigens; Cell Proliferation; Cells, Cultured; Female; Humans; Immunologic Factors; Interleukin-2 Receptor alpha Subunit; Lenalidomide; Lymphoma; Male; Middle Aged; Sirolimus; T-Lymphocytes, Regulatory; Thalidomide

During primary Ag encounter, T cells receive numerous positive and negative signals that control their proliferation, function, and differentiation, but how these signals are integrated to modulate T cell memory has not been fully characterized. In these studies, we demonstrate that combining seemingly opposite signals, CTLA-4 blockade and rapamycin-mediated mammalian target of rapamycin inhibition, during in vivo T cell priming leads to both an increase in the frequency of memory CD8(+) T cells and improved memory responses to tumors and bacterial challenges. This enhanced efficacy corresponds to increased early expansion and memory precursor differentiation of CD8(+) T cells and increased mitochondrial biogenesis and spare respiratory capacity in memory CD8(+) T cells in mice treated with anti-CTLA-4 and rapamycin during immunization. Collectively, these results reveal that mammalian target of rapamycin inhibition cooperates with rather than antagonizes blockade of CTLA-4, promoting unrestrained effector function and proliferation, and an optimal metabolic program for CD8(+) T cell memory.

Topics: Animals; Antibodies, Monoclonal; CD8-Positive T-Lymphocytes; Cell Differentiation; Cell Proliferation; CTLA-4 Antigen; Gene Expression Regulation; Immunologic Memory; Listeria monocytogenes; Listeriosis; Lymphocyte Activation; Lymphoma; Mice; Mice, Inbred C57BL; Mice, Transgenic; Ovalbumin; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Tumor cells disseminate into compartments that are poorly accessible from circulation, which necessitates high doses of systemic chemotherapy. However, the effectiveness of many drugs, such as the potent topoisomerase I poison SN-38, is hampered by poor pharmacokinetics. To deliver SN-38 to lymphoma tumors in vivo, we took advantage of the fact that healthy lymphocytes can be programmed to phenocopy the biodistribution of the tumor cells. In a murine model of disseminated lymphoma, we expanded autologous polyclonal T cells ex vivo under conditions that retained homing receptors mirroring lymphoma cells, and functionalized these T cells to carry SN-38-loaded nanocapsules on their surfaces. Nanocapsule-functionalized T cells were resistant to SN-38 but mediated efficient killing of lymphoma cells in vitro. Upon adoptive transfer into tumor-bearing mice, these T cells served as active vectors to deliver the chemotherapeutic into tumor-bearing lymphoid organs. Cell-mediated delivery concentrated SN-38 in lymph nodes at levels 90-fold greater than free drug systemically administered at 10-fold higher doses. The live T cell delivery approach reduced tumor burden significantly after 2 weeks of treatment and enhanced survival under conditions where free SN-38 and SN-38-loaded nanocapsules alone were ineffective. These results suggest that tissue-homing lymphocytes can serve as specific targeting agents to deliver nanoparticles into sites difficult to access from the circulation, and thus improve the therapeutic index of chemotherapeutic drugs with unfavorable pharmacokinetics.

Topics: Animals; Antineoplastic Agents; Bystander Effect; Camptothecin; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cytotoxicity, Immunologic; Drug Delivery Systems; Humans; Interleukin-2; Irinotecan; Lymph Nodes; Lymphoma; Mice; Nanocapsules; Nanoparticles; Receptors, Lymphocyte Homing; Sirolimus; T-Lymphocytes; Treatment Outcome

The tumor suppressor gene FBXW7 is deleted and mutated in many different types of human cancers. FBXW7 primarily exerts its tumor suppressor activity by ubiquitinating different oncoproteins including mTOR. Here we used gene transcript profiling to gain a deeper understanding of the role of FBXW7 in tumor development and to determine the influence of mTOR inhibition by rapamycin on tumor transcriptome and biological functions. In comparison to tumors from p53 single heterozygous (p53+/-) mice, we find that radiation-induced thymic lymphomas from Fbxw7/p53 double heterozygous (Fbxw7+/-p53+/-) mice show significant deregulation of cholesterol metabolic processes independent of rapamycin treatment, while cell cycle related genes were upregulated in tumors from placebo treated Fbxw7+/-p53+/- mice, but not in tumors from rapamycin treated Fbxw7+/-p53+/- mice. On the other hand, tumors from rapamycin treated Fbxw7+/-p53+/- mice were enriched for genes involved in the integrated stress response, an adaptive mechanism to survive in stressful environments. Finally, we demonstrated that the Fbxw7 gene signatures identified in mouse tumors significantly overlap with FBXW7 co-expressed genes in human cancers. Importantly these common FBXW7 gene signatures between mouse and human are predictive for disease-free survival in human colon, breast and lung adenocarcinoma cancer patients. These results provide novel insights into the role of FBXW7 in tumor development and have identified a number of potential targets for therapeutic intervention.

Topics: Animals; Antineoplastic Agents; Cell Cycle; Cell Cycle Proteins; Cholesterol; Databases, Genetic; Disease Models, Animal; F-Box Proteins; F-Box-WD Repeat-Containing Protein 7; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Genotype; Heterozygote; Humans; Lymphoma; Mice, Knockout; Neoplasms, Radiation-Induced; Phenotype; Protein Kinase Inhibitors; Sirolimus; Thymus Neoplasms; TOR Serine-Threonine Kinases; Transcription, Genetic; Tumor Suppressor Protein p53; Ubiquitin-Protein Ligases

Autophagy is closely related to tumor cell sensitivity to anticancer drugs. The HDAC (histone deacetylase) inhibitor valproic acid (VPA) interacted synergistically with chemotherapeutic agents to trigger lymphoma cell autophagy, which resulted from activation of AMPK (AMP-activated protein kinase) and inhibition of downstream MTOR (mechanistic target of rapamycin [serine/threonine kinase]) signaling. In an HDAC-independent manner, VPA potentiated the effect of doxorubicin on lymphoma cell autophagy via reduction of cellular inositol 1,4,5 trisphosphate (IP3), blockade of calcium into mitochondria and modulation of PRKAA1/2-MTOR cascade. In murine xenograft models established with subcutaneous injection of lymphoma cells, dual treatment of VPA and doxorubicin initiated IP3-mediated calcium depletion and PRKAA1/2 activation, induced in situ autophagy and efficiently retarded tumor growth. Aberrant genes involving mitochondrial calcium transfer were frequently observed in primary tumors of lymphoma patients. Collectively, these findings suggested an HDAC-independent chemosensitizing activity of VPA and provided an insight into the clinical application of targeting autophagy in the treatment of lymphoma.

Topics: AMP-Activated Protein Kinases; Antineoplastic Agents; Autophagy; Cell Line, Tumor; Drug Synergism; Enzyme Activation; Humans; Inositol 1,4,5-Trisphosphate; Lymphoma; Mitochondria; Signal Transduction; Sirolimus; Valproic Acid

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

Few studies examined the clinicopathologic features of PTLD arising in pediatric SBT patients. Particularly, the association between ATG and PTLD in this population has not been described. Retrospective review of 81 pediatric patient charts with SBT--isolated or in combination with other organs--showed a PTLD incidence of 11%, occurring more frequently in females (median age of four yr) and with clinically advanced disease. Monomorphic PTLD was the most common histological subtype. There was a significant difference in the use of ATG between patients who developed PTLD and those who did not (p < 0.01); a similar difference was seen with the use of sirolimus (p < 0.001). These results suggested a link between the combination of ATG and sirolimus and development of more clinically and histologically advanced PTLD; however, the risk of ATG by itself was not clear. EBV viral loads were higher in patients with PTLD, and median time between detection of EBV to PTLD diagnosis was three months. However, viral loads at the time of PTLD diagnosis were most often lower than at EBV detection, thereby raising questions on the correlation between decreasing viral genomes and risk of PTLD.

Topics: Adolescent; Antilymphocyte Serum; Child; Child, Preschool; Female; Gene Rearrangement; Genome, Viral; Humans; Immunosuppressive Agents; In Situ Hybridization; Infant; Intestinal Diseases; Intestine, Small; Lymphoma; Lymphoproliferative Disorders; Male; Postoperative Complications; Retrospective Studies; Risk; Sirolimus; VDJ Recombinases; Viral Load; Young Adult

MYC deregulation is common in human cancer. IG-MYC translocations that are modeled in Eμ-Myc mice occur in almost all cases of Burkitt lymphoma as well as in other B-cell lymphoproliferative disorders. Deregulated expression of MYC results in increased mTOR complex 1 (mTORC1) signaling. As tumors with mTORC1 activation are sensitive to mTORC1 inhibition, we used everolimus, a potent and specific mTORC1 inhibitor, to test the requirement for mTORC1 in the initiation and maintenance of Eμ-Myc lymphoma. Everolimus selectively cleared premalignant B cells from the bone marrow and spleen, restored a normal pattern of B-cell differentiation, and strongly protected against lymphoma development. Established Eμ-Myc lymphoma also regressed after everolimus therapy. Therapeutic response correlated with a cellular senescence phenotype and induction of p53 activity. Therefore, mTORC1-dependent evasion of senescence is critical for cellular transformation and tumor maintenance by MYC in B lymphocytes.. This work provides novel insights into the requirements for MYC-induced oncogenesis by showing that mTORC1 activity is necessary to bypass senescence during transformation of B lymphocytes. Furthermore, tumor eradication through senescence elicited by targeted inhibition of mTORC1 identifies a previously uncharacterized mechanism responsible for significant anticancer activity of rapamycin analogues and serves as proof-of-concept that senescence can be harnessed for therapeutic benefit

Topics: Animals; Antineoplastic Agents; B-Lymphocytes; Cell Differentiation; Cellular Senescence; Everolimus; Lymphoma; Male; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Transgenic; Multiprotein Complexes; Proteins; Proto-Oncogene Proteins c-myc; Sirolimus; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR) plays crucial roles in proliferative and antiapoptotic signaling in lymphoid malignancies. Rapamycin analogs, which are allosteric mTOR complex 1 (mTORC1) inhibitors, are active in mantle cell lymphoma and other lymphoid neoplasms, but responses are usually partial and short-lived. In the present study we compared the effects of rapamycin with the dual mTORC1/mTORC2 inhibitor OSI-027 in cell lines and clinical samples representing divers lymphoid malignancies. In contrast to rapamycin, OSI-027 markedly diminished proliferation and induced apoptosis in a variety of lymphoid cell lines and clinical samples, including specimens of B-cell acute lymphocytic leukemia (ALL), mantle cell lymphoma, marginal zone lymphoma and Sezary syndrome. Additional analysis demonstrated that OSI-027-induced apoptosis depended on transcriptional activation of the PUMA and BIM genes. Overexpression of Bcl-2, which neutralizes Puma and Bim, or loss of procaspase 9 diminished OSI-027-induced apoptosis in vitro. Moreover, OSI-027 inhibited phosphorylation of mTORC1 and mTORC2 substrates, up-regulated Puma, and induced regressions in Jeko xenografts. Collectively, these results not only identify a pathway that is critical for the cytotoxicity of dual mTORC1/mTORC2 inhibitors, but also suggest that simultaneously targeting mTORC1 and mTORC2 might be an effective anti-lymphoma strategy in vivo.

Topics: Apoptosis; Apoptosis Regulatory Proteins; Blotting, Western; Cell Proliferation; Humans; Imidazoles; Immunoprecipitation; Immunosuppressive Agents; Lymphoma; Mechanistic Target of Rapamycin Complex 1; Multiprotein Complexes; Phosphorylation; Proteins; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Real-Time Polymerase Chain Reaction; RNA, Messenger; RNA, Small Interfering; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors; Triazines; Tumor Cells, Cultured

Anorexia-cachexia syndrome (ACS) is a major determinant of cancer-related death that causes progressive body weight loss due to depletion of skeletal muscle mass and body fat. Here, we report the development of a novel preclinical murine model of ACS in which lymphomas harbor elevated Myc and activated mTOR signaling. The ACS phenotype in this model correlated with deregulated expression of a number of cytokines, including elevated levels of interleukin-10 which was under the direct translational control of mTOR. Notably, pharmacologic intervention to impair protein synthesis restored cytokine production to near-normal levels, delayed ACS progression, and extended host survival. Together, our findings suggest a new paradigm to treat ACS by strategies which target protein synthesis to block the production of procachexic factors.

Topics: Animals; Anorexia; Antineoplastic Agents; Body Weight; Cachexia; Cell Line, Tumor; Colonic Neoplasms; Disease Models, Animal; Female; Harringtonines; Homoharringtonine; Humans; Interleukin-10; Kaplan-Meier Estimate; Lymphoma; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Protein Biosynthesis; Proto-Oncogene Proteins c-myc; Signal Transduction; Sirolimus; Syndrome; TOR Serine-Threonine Kinases

mTOR (mammalian target of rapamycin) inhibitors were recently found to be effective in the treatment of various human non-Hodgkin's lymphomas (NHLs). We recently reported that RAD001, an mTOR inhibitor, suppressed the growth of lymphoma cells at concentrations much lower than those required for carcinomas. However, the basis for the enhanced sensitivity to RAD001 is unknown. Seven aggressive NHL cell lines and seven carcinoma cell lines were used in this study. Cell cycle was analysed by flow cytometry. pAKT (phosphorylated AKT) (Ser(473) and Thr(308)), p-p70S6K, p-4E-BP1, p-mTOR, p-eIF4E (phosphorylated eIF4E), cyclin A, cyclin E, cyclin D3, c-Myc and insulin receptor substrate-1 (IRS-1) protein expression were assessed by immunoblotting. The PI3K/AKT/mTOR (phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin) signalling pathway was constitutively expressed in all seven lymphoma cell lines. RAD001 down-regulated p-mTOR, p-p70S6K, p-4E-BP1, cyclin A, cyclin E, cyclin D3, and c-Myc, but did not affect IRS-1. In parallel with RAD001-induced inhibition of cell viability, a dose- and schedule- dependent down-regulation of pAKT and p-eIF4E expressions was demonstrated. In contrast, a compensatory activation of pAKT and p-eIF4E, was observed in seven carcinoma cells. These findings indicate that the basis for enhanced activity of mTOR inhibitors in NHL may be the lack of compensatory activation of AKT and eIF4E phosphorylation in lymphoma cells.

Topics: Apoptosis; Carcinoma; Cell Cycle; Cell Line, Tumor; Eukaryotic Initiation Factor-4E; Everolimus; Gene Expression Regulation, Neoplastic; Humans; Immunosuppressive Agents; Jurkat Cells; Lymphoma; Models, Biological; Phosphorylation; Proto-Oncogene Proteins c-akt; Sirolimus; Tetrazolium Salts; Thiazoles; TOR Serine-Threonine Kinases

New anticancer drugs that target oncogenic signaling molecules have greatly improved the treatment of certain cancers. However, resistance to targeted therapeutics is a major clinical problem and the redundancy of oncogenic signaling pathways provides back-up mechanisms that allow cancer cells to escape. For example, the AKT and PIM kinases produce parallel oncogenic signals and share many molecular targets, including activators of cap-dependent translation. Here, we show that PIM kinase expression can affect the clinical outcome of lymphoma chemotherapy. We observe the same in animal lymphoma models. Whereas chemoresistance caused by AKT is readily reversed with rapamycin, PIM-mediated resistance is refractory to mTORC1 inhibition. However, both PIM- and AKT-expressing lymphomas depend on cap-dependent translation, and genetic or pharmacological blockade of the translation initiation complex is highly effective against these tumors. The therapeutic effect of blocking cap-dependent translation is mediated, at least in part, by decreased production of short-lived oncoproteins including c-MYC, Cyclin D1, MCL1, and the PIM1/2 kinases themselves. Hence, targeting the convergence of oncogenic survival signals on translation initiation is an effective alternative to combinations of kinase inhibitors.

Topics: Animals; Antibiotics, Antineoplastic; Drug Resistance, Neoplasm; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; Lymphoma; Mechanistic Target of Rapamycin Complex 1; Mice; Multiprotein Complexes; Protein Biosynthesis; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Proteins; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-pim-1; RNA Caps; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors; Tumor Cells, Cultured

Lymphangiomatosis is a rare and fatal congenital lymphatic malformation. Because the natural course of the disease affects multiple body systems, the management can be challenging. This article presents a novel approach to the treatment of diffuse lymphangiomatosis using sirolimus. The reported case involves a 4-month-old male with a known lymphatic malformation who presented to the emergency department with respiratory difficulties. Sirolimus was successful at significantly reducing our patient's mass at a relatively low target level of 5 to 10 μg/L. The use of sirolimus for the treatment of lymphangiomatosis should be studied further in the setting of a formal trial.

Topics: Antibiotics, Antineoplastic; Diagnosis, Differential; Head and Neck Neoplasms; Humans; Infant; Lymphangioma; Lymphoma; Magnetic Resonance Imaging; Male; Sirolimus; Ultrasonography

Abnormal thymocyte development with thymic lymphomagenesis inevitably occurs in Atm-/- mice, indicating that ATM plays a pivotal role in regulating postnatal thymocyte development and preventing thymic lymphomagenesis. The mechanism for ATM controls these processes is unclear. We have shown previously that c-Myc, an oncoprotein regulated by the mammalian target of rapamycin (mTOR), is overexpressed in Atm-/- thymocytes. Here, we show that inhibition of mTOR signaling with its specific inhibitor, rapamycin, suppresses normal thymocyte DNA synthesis by downregulating 4EBP1, but not S6K, and that 4EBP1 phosphorylation and cyclin D1 expression are coordinately increased in Atm-/- thymocytes. Administration of rapamycin to Atm-/- mice attenuates elevated phospho-4EBP1, c-Myc and cyclin D1 in their thymocytes, and delays thymic lymphoma development. These results indicate that mTOR downstream effector 4EBP1 is essential for normal thymocyte proliferation, but deregulation of 4EBP1 in Atm deficiency is a major factor driving thymic lymphomagenesis in the animals.

Topics: Adaptor Proteins, Signal Transducing; Animals; Antibiotics, Antineoplastic; Ataxia Telangiectasia Mutated Proteins; Carrier Proteins; Cell Cycle Proteins; Cyclin D1; DNA Replication; DNA-Binding Proteins; Eukaryotic Initiation Factors; Lymphoma; Mice; Mice, Knockout; Phosphoproteins; Phosphotransferases (Alcohol Group Acceptor); Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-myc; Signal Transduction; Sirolimus; Thymus Neoplasms; TOR Serine-Threonine Kinases; Tumor Suppressor Proteins

To be a reliable predictor of response, tracer uptake should reflect changes in the amount of active tumor cells. However, uptake of (18)F-FDG, the most commonly used PET tracer, is disturbed by the inflammatory cells that appear early after cytotoxic therapy. The first aim of this study was to investigate whether 3'-(18)F-fluoro-3'-deoxy-l-thymidine ((18)F-FLT), a marker of cellular proliferation, is a better tracer for response assessment early after cytotoxic therapy. A second objective of this study was to investigate whether (18)F-FDG and (18)F-FLT responses were comparable early after mammalian target of rapamycin (mTOR) inhibition, as an example of proliferation-targeting therapies.. Severe combined immunodeficient mice were subcutaneously inoculated with Granta-519 cells, a human cell line derived from a leukemic mantle cell lymphoma. Half the mice were treated with cyclophosphamide and the other half with mTOR inhibition. (18)F-FDG and (18)F-FLT uptake was evaluated by small-animal PET on day 0 (D0; before treatment), D+1, D+2, D+4, D+7, D+9, D+11, and D+14. At each time point, 2 mice of each treatment condition were sacrificed, and tumors were excised for histopathology.. After cyclophosphamide, (18)F-FDG and (18)F-FLT uptake decreased, with a maximum reduction of -29% for (18)F-FDG and -25% for (18)F-FLT uptake at D+2, compared with baseline. Although (18)F-FDG uptake increased from D+4 on, with a maximum on D+7, (18)F-FLT uptake remained virtually stable. Histology showed an increase in apoptotic or necrotic tumor fraction, followed by an influx of inflammatory cells. In mTOR-inhibited mice, (18)F-FDG uptake dropped until D+2 after therapy (-43%) but increased at D+4 (-27%) to form a plateau on D+7 and D+9 (-14% and -16%, respectively). Concurrently, (18)F-FLT uptake decreased to -31% on D+2, followed by an increase with a peak value of +12% on D+7, after which (18)F-FLT uptake decreased again. Cyclin D1 expression dropped from D+1 until D+4 and returned to baseline at D+7.. Because (18)F-FLT uptake is not significantly influenced by the temporary rise in inflammatory cells early after cyclophosphamide, it more accurately reflects tumor response. However, a formerly unknown temporary rise in (18)F-FLT uptake a few days after the administration of mTOR inhibition was defined, which makes it clear that drug-specific responses have to be considered when using PET for early treatment monitoring.

Topics: Animals; Antineoplastic Agents, Alkylating; Cell Line, Tumor; Cyclophosphamide; Dideoxynucleosides; Fluorodeoxyglucose F18; Humans; Lymphoma; Metabolic Clearance Rate; Mice; Mice, SCID; Protein Kinase Inhibitors; Protein Kinases; Radionuclide Imaging; Radiopharmaceuticals; Sirolimus; Tissue Distribution; TOR Serine-Threonine Kinases; Treatment Outcome

Topics: Calcineurin Inhibitors; Disease-Free Survival; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Kaplan-Meier Estimate; Lymphoma; Methotrexate; Sirolimus; Transplantation Conditioning; Transplantation, Homologous; Treatment Outcome

Disablement of cell death programs in cancer cells contributes to drug resistance and in some cases has been associated with altered translational control. As eukaryotic translation initiation factor 4E (eIF4E) cooperates with c-Myc during lymphomagenesis, induces drug resistance, and is a genetic modifier of the rapamycin response, we have investigated the effect of dysregulation of the ribosome recruitment phase of translation initiation on tumor progression and chemosensitivity. eIF4E is a subunit of eIF4F, a complex that stimulates ribosome recruitment during translation initiation by delivering the DEAD-box RNA helicase eIF4A to the 5' end of mRNAs. eIF4A is thought to prepare a ribosome landing pad on mRNA templates for incoming 40S ribosomes (and associated factors). Using small molecule screening, we found that cyclopenta[b]benzofuran flavaglines, a class of natural products, modulate eIF4A activity and inhibit translation initiation. One member of this class of compounds, silvestrol, was able to enhance chemosensitivity in a mouse lymphoma model in which carcinogenesis is driven by phosphatase and tensin homolog (PTEN) inactivation or elevated eIF4E levels. These results establish that targeting translation initiation can restore drug sensitivity in vivo and provide an approach to modulating chemosensitivity.

Topics: Animals; Apoptosis; Benzofurans; Cell Line; Cell Line, Tumor; Disease Models, Animal; Doxorubicin; Drug Resistance, Neoplasm; Drug Synergism; Eukaryotic Initiation Factor-4A; Eukaryotic Initiation Factor-4E; Female; HeLa Cells; Humans; Lymphoma; Mice; Mice, Inbred C57BL; Peptide Chain Initiation, Translational; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerases; Polyribosomes; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Sirolimus; Thapsigargin; Triterpenes

Activation of the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway is a frequent occurrence in human cancers and a major promoter of chemotherapeutic resistance. Inhibition of one downstream target in this pathway, mTORC1, has shown potential to improve chemosensitivity. However, the mechanisms and genetic modifications that confer sensitivity to mTORC1 inhibitors remain unclear. Here, we demonstrate that loss of TSC2 in the E mu-myc murine lymphoma model leads to mTORC1 activation and accelerated oncogenesis caused by a defective apoptotic program despite compromised AKT phosphorylation. Tumors from Tsc2(+/-)E mu-Myc mice underwent rapid apoptosis upon blockade of mTORC1 by rapamycin. We identified myeloid cell leukemia sequence 1 (Mcl-1), a bcl-2 like family member, as a translationally regulated genetic determinant of mTORC1-dependent survival. Our results indicate that the extent by which rapamycin can modulate expression of Mcl-1 is an important feature of the rapamycin response.

Topics: Animals; Gene Expression Regulation, Neoplastic; Immunoblotting; Immunoprecipitation; Lymphoma; Mechanistic Target of Rapamycin Complex 1; Mice; Multiprotein Complexes; Myeloid Cell Leukemia Sequence 1 Protein; Proteins; Proto-Oncogene Proteins c-bcl-2; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors; Tuberous Sclerosis Complex 2 Protein; Tumor Suppressor Proteins

Topics: Adult; Aged; Antibiotics, Antineoplastic; Disease-Free Survival; Graft vs Tumor Effect; Haplotypes; Hematopoietic Stem Cell Transplantation; Humans; Lymphoma; Medical Oncology; Middle Aged; Risk; Sirolimus; Stem Cells; Treatment Outcome

The AKT-mTOR pathway harbors several known and putative oncogenes and tumor suppressors. In a phenotypic screen for lymphomagenesis, we tested candidate genes acting upstream of and downstream from mTOR in vivo. We find that Rheb, a proximal activator of mTORC1, can produce rapid development of aggressive and drug-resistant lymphomas. Rheb causes mTORC1-dependent effects on apoptosis, senescence, and treatment responses that resemble those of Akt. Moreover, Rheb activity toward mTORC1 requires farnesylation and is readily blocked by a pharmacological inhibitor of farnesyltransferase (FTI). In Pten-deficient tumor cells, inhibition of Rheb by FTI is responsible for the drug's anti-tumor effects, such that a farnesylation-independent mutant of Rheb renders these tumors resistant to FTI therapy. Notably, RHEB is highly expressed in some human lymphomas, resulting in mTORC1 activation and increased sensitivity to rapamycin and FTI. Downstream from mTOR, we examined translation initiation factors that have been implicated in transformation in vitro. Of these, only eIF4E was able to enhance lymphomagenesis in vivo. In summary, the Rheb GTPase is an oncogenic activity upstream of mTORC1 and eIF4E and a direct therapeutic target of farnesyltransferase inhibitors in cancer.

Topics: Animals; Antibiotics, Antineoplastic; Blotting, Western; Cell Transformation, Neoplastic; Cells, Cultured; Cellular Senescence; Doxorubicin; Eukaryotic Initiation Factor-4E; Farnesyltranstransferase; Female; Fibroblasts; Gene Dosage; Humans; Immunophenotyping; Immunosuppressive Agents; Lymphoma; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Inbred C57BL; Mice, Knockout; Monomeric GTP-Binding Proteins; Multiprotein Complexes; Neuropeptides; Phosphorylation; Piperidines; Proteins; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-myc; PTEN Phosphohydrolase; Pyridines; Ras Homolog Enriched in Brain Protein; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors; Tumor Suppressor Protein p53

Sirolimus is an effective agent used in graft-versus-host disease (GVHD) prophylaxis after allogeneic transplantation. It also has antiproliferative effects on vascular endothelium when used to coat coronary artery stents. We noted an excess of veno-occlusive disease (VOD) in a clinical trial, and retrospectively reviewed the records of 488 patients to determine the association between sirolimus and VOD. When used with cyclophosphamide/total body irradiation (Cy/TBI) conditioning, sirolimus is associated with an increased incidence of VOD (OR 2.35, P = .005). The concomitant use of methotrexate further increased this rate (OR 3.23, P < .001), while sirolimus without methotrexate was not associated with an increased risk of VOD (OR 1.55, P = .33). Mortality after VOD diagnosis was unaffected, and overall treatment-related mortality was lowest when sirolimus was used without methotrexate. Similar findings were noted in matched, related, and unrelated as well as mismatched donor subgroups. When used with busulfan-based conditioning, sirolimus use was associated with an even higher rate of VOD (OR 8.8, P = .008). Our findings suggest that sirolimus use is associated with VOD after TBI-based transplantation when used with methotrexate after transplantation. Sirolimus-based GVHD prophylaxis without methotrexate is associated with the greatest overall survival. Myeloablative doses of busulfan should not be used with sirolimus-based immunosuppression.

Topics: Adolescent; Adult; Drug Combinations; Female; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Hepatic Veno-Occlusive Disease; Humans; Immunosuppressive Agents; Incidence; Leukemia; Lymphoma; Male; Middle Aged; Retrospective Studies; Sirolimus; Transplantation Conditioning; Transplantation, Homologous; Young Adult

Inhibitors of the mammalian target of rapamycin (mTOR) kinase have shown clinical activity in several lymphoma subtypes. Sirolimus, an mTOR inhibitor, also has activity in the treatment and prophylaxis of graft-versus-host disease (GVHD) after allogeneic hematopoietic stem-cell transplantation (HSCT). We hypothesized that the use of sirolimus for GVHD prophylaxis in patients with lymphoma might lead to improved survival after transplantation through a decreased incidence of disease progression.. We retrospectively analyzed 190 patients who underwent transplantation for lymphoma. We compared the outcomes of patients who received sirolimus for GVHD prophylaxis with those of patients who received transplantation with a combination of a calcineurin inhibitor and methotrexate without sirolimus.. Overall survival (OS) after transplantation was significantly superior in the sirolimus group, which was confirmed in multivariable analysis. The benefit was restricted to patients undergoing reduced-intensity conditioning (RIC) HSCT (3-year OS, 66% for sirolimus group v 38% for no-sirolimus group; P = .007; hazard ratio [HR] for mortality in multivariable analysis = 0.5, P = .042). Patients who received sirolimus had a similar incidence of nonrelapse mortality but a decreased incidence of disease progression compared with patients who did not receive sirolimus (3-year cumulative incidence of progression, 42% v 74%, respectively; P < .001; HR for progression in multivariable analysis = 0.4, P = .01). The effect of sirolimus persisted after adjusting for the occurrence of GVHD. No such survival advantage was apparent in a similar comparison of patients who underwent transplantation for diseases other than lymphoma.. This study suggests that sirolimus can independently decrease the risk of lymphoma progression after RIC HSCT, paving the way for prospective clinical trials.

Topics: Adult; Aged; Boston; Calcineurin; Calcineurin Inhibitors; Disease-Free Survival; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Kaplan-Meier Estimate; Lymphoma; Methotrexate; Middle Aged; Retrospective Studies; Sirolimus; Time Factors; Transplantation Conditioning; Transplantation, Homologous; Treatment Outcome; Young Adult

To investigate the relationship between mTOR signaling pathway and ALK-positive lymphoid cell lines.. The expression of the downstream effector proteins of mTOR were analyzed by Western blot before and after Karpas299, BaF3/NPM-ALK and BaF3 cell lines treated with rapamycin. Effect of rapamycin on cell proliferation was detected by MTT assay. FACS was used to analyze apoptosis and cell cycles.. mTOR signaling phosphoproteins, p-p70S6K and p-4E-BP1 were highly expressed in ALK(+) Karpas299, BaF3/NPM-ALK and parental BaF3 cell lines, and they were dephosphorylated after 1 h withdrawal of IL-3 in BaF3 cells. After 48 h exposure to 10 nmol/L rapamycin, p-p70S6K and p-4E-BP1 proteins expression were decreased, and mainly for the former. The relative inhibitory rate to its control cells was 24.4% in Karpas299, 37.8% in BaF3/NPM-ALK and 61.6% in BaF3. The apoptotic ratio was increased from (11.97 +/- 0.11)% to (15.87 +/- 0.62)% in Karpas299 (P < 0.05), from (3.23 +/- 0.11)% to (7.67 +/- 0.49)% in BaF3 (P < 0.05) and from (1.90 +/- 0.47)% to (2.80 +/- 0.27)% in BaF3/NPM-ALK (P > 0.05). The fraction of G(1) phase cells increased from (37.63 +/- 1.91)% to (69.77 +/- 5.44)% in BaF3/NPM-ALK, from (31.13 +/- 2.51)% to (40.70 +/- 1.47)% in Karpas299 and (53.57 +/- 2.22)% to (63.70 +/- 1.20)% in BaF3 (P < 0.05).. NPM-ALK kinase can activate mTOR signaling pathway. Rapamycin can inhibit the proliferation of ALK(+) lymphoid cells by blocking mTOR signaling pathway and inducing cell cycling arrest at G(1) phase.

Topics: Anaplastic Lymphoma Kinase; Animals; Apoptosis; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Humans; Intracellular Signaling Peptides and Proteins; Lymphoma; Mice; Protein Serine-Threonine Kinases; Protein-Tyrosine Kinases; Receptor Protein-Tyrosine Kinases; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

IPEX syndrome (immune deficiency, polyendocrinopathy, enteropathy, X-linked) is a disorder or regulatory T cell (Treg) function which can result in early death due to infection or complications related to autoimmunity. Therapeutic options for these patients can include allogeneic stem cell transplantation (SCT) or the use of immunosuppressive regimens to control the manifestations of autoimmunity. We report a patient with IPEX syndrome who was managed with rapamycin and subsequently developed EBV induced lymphoma.

Topics: Child; Epstein-Barr Virus Infections; Genetic Diseases, X-Linked; Herpesvirus 4, Human; Humans; Immunologic Deficiency Syndromes; Immunosuppressive Agents; Infant; Lymphoma; Male; Polyendocrinopathies, Autoimmune; Protein-Losing Enteropathies; Sirolimus; Syndrome

The antitumor potency of the mTOR inhibitor rapamycin (sirolimus) is the subject of intense investigations. Primary effusion lymphoma (PEL) appears as an AIDS-defining lymphoma and like Kaposi sarcoma has been linked to Kaposi sarcoma-associated herpesvirus (KSHV). We find that (1) rapamycin is efficacious against PEL in culture and in a murine xenograft model; (2) mTOR, its activator Akt, and its target p70S6 kinase are phosphorylated in PEL; (3) rapamycin inhibits mTOR signaling as determined by S6 phosphorylation; (4) KSHV transcription is unaffected; (5) inhibition of IL-10 signaling correlates with drug sensitivity; and (6) addition of exogenous IL-10 or IL-6 can reverse the rapamycin growth arrest. This validates sirolimus as a new treatment option for PEL.

Topics: Animals; Autocrine Communication; Cell Line, Tumor; Cell Proliferation; Cytokines; Disease Progression; Herpesvirus 8, Human; Humans; Lymphoma; Mice; RNA, Messenger; Sirolimus; Transcription, Genetic; Xenograft Model Antitumor Assays

Alpha4 phosphoprotein in the mTOR pathway is a prolactin (PRL)-downregulated gene product that interacts with the catalytic subunit of serine/threonine protein phosphatase 2A (PP2Ac) in rat Nb2 lymphoma cells. Transient overexpression of alpha4 in COS-1 cells inhibited PRL-inducible interferon-regulatory-1 (IRF-1) promoter activity, but the mechanism underlying this inhibition was not known. The present study showed a stable alpha4-PP2Ac complex that was not dissociated by rapamycin in COS-1 cells. Transient overexpression of alpha4 in COS-1 cells had no effect on endogenous PP2Ac protein levels but significantly increased PP2Ac carboxymethylation and PP2A activity as compared to controls. The increased PP2A activity was accompanied by decreased phosphorylation of eukaryotic initiation factor 4E-binding protein (4E-BP1) but had no effect on Stat phosphorylation. However, overexpressed alpha4 decreased arginine methylation of Stat1alpha and increased Stat1alpha binding to the Stat1alpha-specific inhibitor, PIAS1. In summary, ectopic alpha4 increased PP2A activity in COS-1 cells and this was accompanied by Stat1alpha hypomethylation and increased Stat1alpha-PIAS1 association. These events would inhibit Stat action and ultimately inhibit PRL-inducible IRF-1 promoter activity.

Topics: Animals; Carrier Proteins; Cell Line, Tumor; Chloramphenicol O-Acetyltransferase; Chlorocebus aethiops; COS Cells; Immunoprecipitation; Interferon Regulatory Factor-1; Intracellular Signaling Peptides and Proteins; Lymphoma; Methylation; Phosphoprotein Phosphatases; Phosphoproteins; Phosphorylation; Prolactin; Promoter Regions, Genetic; Protein Inhibitors of Activated STAT; Protein Kinases; Protein Phosphatase 2; Rats; Signal Transduction; Sirolimus; STAT1 Transcription Factor; TOR Serine-Threonine Kinases

Topics: Animals; Antineoplastic Agents; Graft vs Host Disease; Hematology; Humans; Immunosuppressive Agents; Interleukin-2 Receptor alpha Subunit; Leukemia; Leukemia, Myeloid; Lymphoma; Porifera; Sirolimus; Stem Cell Transplantation; Stem Cells; Tacrolimus

Topics: Anemia, Sickle Cell; Antibiotics, Antineoplastic; Antigens, CD20; Benzamides; Benzenesulfonates; CD40 Antigens; Diphenylamine; Hematologic Neoplasms; Hematology; Humans; Ki-1 Antigen; Leukemia, Myeloid; Lymphoma; MAP Kinase Kinase Kinases; Niacinamide; Phenylurea Compounds; Pyridines; Sirolimus; Sorafenib

Myelosuppression is the most common unwanted side effect associated with the administration of anticancer drugs, and infections remain a common cause of death in chemotherapy-treated patients. Several mechanisms of the cytotoxicity of these drugs have been proposed and may synergistically operate in a given cell. Survivin expression has been associated with cancer, but recent reports suggest that this molecule is also expressed in several immature and mature hematopoietic cells. Here, we provide evidence that treatment of immature neutrophils with anticancer drugs reduced endogenous survivin levels causing apoptosis. The anticancer drugs did not directly target survivin, instead they blocked the activity of phosphatidylinositol-3-OH kinase, which regulated survivin expression and apoptosis in these cells. Strikingly, and in contrast to other cells, this pathway did not involve the serine/threonine kinase c-akt/PKB. Moreover, in combination with anticancer drug therapy, rapamycin did not induce increased myelosuppression in an experimental lymphoma mouse model. These data suggest that drugs that block either c-akt/PKB or signaling molecules located distal to c-akt/PKB may preferentially induce apoptosis of cancer cells as they exhibit no cytotoxicity for immature neutrophils.

Topics: 3-Phosphoinositide-Dependent Protein Kinases; Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Bone Marrow; Cells, Cultured; Doxorubicin; Female; Flow Cytometry; Humans; Immunoblotting; Inhibitor of Apoptosis Proteins; Lymphoma; Mice; Mice, Inbred C57BL; Microtubule-Associated Proteins; Neoplasm Proteins; Neoplasms, Experimental; Neutrophils; Phosphatidylinositol 3-Kinases; Polymerase Chain Reaction; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-akt; Sirolimus; Stem Cells; Survivin

The phosphatidylinositol-3-OH kinase [PI(3)K] pathway is frequently activated in human cancers and represents a rational target for therapeutic intervention. We have previously shown that enforced expression of Akt, which is a downstream effector of PI(3)K, could promote tumorigenesis and drug resistance in the Emu-myc mouse lymphoma model, and that these tumors were particularly sensitive to inhibition of mammalian target of rapamycin (mTOR) with rapamycin when combined with conventional chemotherapy. We now show that reduced dosage of PTEN, a negative regulator of PI(3)K signaling, is sufficient to activate Akt, but has only a modest effect on lymphomagenesis in the same model. Nonetheless, loss of even one PTEN allele resulted in lymphomas that were resistant to conventional chemotherapy yet sensitive to rapamycin/chemotherapy combinations. These effects could be recapitulated by using RNA interference to suppress PTEN expression in lymphomas, which were previously established in the absence of PI(3)K lesions. Finally, the introduction of lesions that act downstream of mTOR (eIF4E) or disable apoptosis (Bcl-2 and loss of p53) into PTEN+/- lymphomas promoted resistance to rapamycin/chemotherapy combinations. Thus, whether activation of the PI(3)K pathway confers sensitivity or resistance to therapy depends on the therapy used as well as secondary genetic events. Understanding these genotype-response relationships in human tumors will be important for the effective use of rapamycin or other compounds targeting the PI(3)K pathway in the clinic.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Drug Resistance, Neoplasm; Enzyme Activation; Female; Genes, myc; Heterozygote; Lymphoma; Male; Mice; Mice, Inbred C57BL; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Sirolimus

Mitogens activate the mammalian target-of-rapamycin (mTOR) pathway through phosphatidylinositol 3-kinase (PI3K). The activated mTOR kinase phosphorylates/ activates ribosomal protein S6 kinase (p70S6K) and phosphorylates/inactivates eukaryotic initiation factor 4E-binding protein-1 (4E-BP1), resulting in the initiation of translation and cell-cycle progression. The prolactin receptor signaling cascade has been implicated in crosstalk with the mTOR pathway, but whether prolactin (PRL) directly activates mTOR is not known. This study showed that PRL stimulated the phosphorylation of mTOR, p70S6K, Akt, and Jak2 kinases in a dose- and time-dependent manner in PRL-dependent rat Nb2 lymphoma cells. PRL-stimulated phosphorylation of mTOR was detected as early as 10 min, closely following the phosphorylation of Akt (upstream of mTOR), but preceding that of the downstream p70S6K. PRL activation of mTOR was inhibited by rapamycin (mTOR inhibitor), LY249002, and wortmannin (P13K inhibitors), but not by AG490 (Jak2 inhibitor), indicating that it was mediated by the P13K/Akt, but not Jak2, pathway. PRL also stimulated phosphorylation of 4E-BP1 in Nb2 cells. PRL-induced phosphorylation of p70S6K and 4E-BP1 was inhibited by rapamycin, but not by okadaic acid (inhibitor of protein phosphatase, PP2A). PRL induced a transient interaction between p70S6K and the catalytic subunit of PP2A (PP2Ac) in 1 and 2 h, whereas a PP2Ac-4E-BP1 complex was constitutively present in quiescent and PRL-treated Nb2 cells. These results suggested that p70S6K and 4E-BP1 were substrates of PP2A and the inhibition of mTOR promoted their dephosphorylation by PP2A. In summary, PRL-stimulated phosphorylation of mTOR is mediated by PI3K. PRL-activated mTOR may phosphorylate p70S6K and 4E-BP1 by restraining PP2A.

Topics: Androstadienes; Animals; Blotting, Western; Carrier Proteins; Cell Line, Tumor; Chromones; Enzyme Inhibitors; Immunoprecipitation; Intracellular Signaling Peptides and Proteins; Lymphoma; Morpholines; Okadaic Acid; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphoproteins; Prolactin; Protein Kinases; Rats; Ribosomal Protein S6 Kinases, 70-kDa; Sirolimus; Stimulation, Chemical; TOR Serine-Threonine Kinases; Wortmannin

The mammalian target of rapamycin (mTOR) pathway plays important roles in regulating nutrient metabolism and promoting the growth and survival of cancer cells, which exhibit increased glycolysis for ATP generation. In this study, we tested the hypothesis that inhibition of the mTOR pathway and glycolysis would synergistically impact the energy metabolism in cancer cells and may serve as an effective therapeutic strategy to kill malignant cells. Using human lymphoma cells and leukemia cells, we demonstrated that the combination of rapamycin, an mTOR inhibitor, with a glycolytic inhibitor produced synergistic cytotoxic effect, as evidenced by apoptosis and cell growth inhibition assays. Mechanistic studies showed that inhibition of the mTOR pathway by rapamycin alone sufficiently suppressed the phosphorylation of the downstream molecules p70S6K and 4E-BP-1, but only caused a moderate cytostatic effect. Combination of mTOR inhibition and blockage of glycolysis synergistically suppressed glucose uptake and severely depleted cellular ATP pools, leading to significant enhancement of cell killing. In contrast, combination of rapamycin and ara-C did not increase cytotoxicity in vitro. Our findings suggest that targeting mTOR pathway in combination with inhibition of glycolysis may be an effective therapeutic strategy for hematological malignancies. This mechanism-based drug combination warrants further investigation in preclinical and clinical settings.

Topics: Adenosine Triphosphate; Apoptosis; Cell Proliferation; Cytarabine; Drug Synergism; Energy Metabolism; Glycolysis; Humans; Leukemia; Lymphoma; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases; Tumor Cells, Cultured

The eukaryotic initiation factor 4E (eIF4E) is a key regulator of protein translation whose function is activated by the Akt and Ras proto-oncogenic signal transduction pathways. eIF4E enhances the translation of mRNAs encoding several genes involved in tumorigenesis and acts as a proto-oncogene, in vitro, when overexpressed in immortalized cells. Importantly, eIF4E is frequently found overexpressed in human cancers of multiple histological origins. However, in vivo evidence of the eIF4E neoplastic potential was lacking until now. Here we discuss recent findings that demonstrate eIF4E's oncogenic role in vivo through direct genetic approaches in the mouse, and identify novel oncogenic functions for this initiation factor in cooperative tumorigenesis and response to therapy.

Topics: Animals; Antibiotics, Antineoplastic; Cell Transformation, Neoplastic; Drug Resistance, Neoplasm; Eukaryotic Initiation Factor-4E; Gene Expression Regulation, Neoplastic; Humans; Lymphoma; Mice; Mice, Transgenic; Models, Genetic; Protein Biosynthesis; Protein Kinase Inhibitors; Proto-Oncogene Mas; Proto-Oncogenes; Sirolimus

We have investigated the effect of inducing apoptosis in BJAB and Jurkat cells on the cellular content of several polypeptide chain initiation factors. Serum deprivation results in inhibition of protein synthesis and induction of apoptosis in BJAB cells; at early times, there is selective degradation of polypeptide initiation factor eIF4G but no major losses of other key initiation factors. The disappearance of full length eIF4G is accompanied by the appearance of smaller forms of the protein, including a major product of approximately 76 kDa. Apoptosis induced by cycloheximide results in similar effects. Both total cytoplasmic eIF4G and eIF4G associated with eIF4E are degraded with a half-life of 2-4 h under these conditions. Treatment of serum-starved or cycloheximide-treated cells with Z-VAD.FMK or Z-DEVD.FMK, which inhibit caspases required for apoptosis, protects eIF4G from degradation and blocks the appearance of the ca. 76 kDa product. Exposure of BJAB cells to rapamycin rapidly inhibits protein synthesis but does not lead to acute degradation of eIF4G. In both BJAB and Jurkat cells induction of apoptosis with anti-Fas antibody or etoposide also results in the selective loss of eIF4G, which is inhibitable by Z-VAD.FMK. These data suggest that eIF4G is selectively targeted for cleavage as cells undergo apoptosis and is a substrate for proteases activated during this process.

Topics: Amino Acid Chloromethyl Ketones; Antibodies; Apoptosis; Caspase Inhibitors; Caspases; Culture Media, Serum-Free; Cycloheximide; Etoposide; Eukaryotic Initiation Factor-4E; fas Receptor; Half-Life; Humans; Jurkat Cells; Lymphoma; Molecular Weight; Neoplasm Proteins; Oligopeptides; Peptide Initiation Factors; Poly(A)-Binding Proteins; Poly(ADP-ribose) Polymerases; Protein Synthesis Inhibitors; RNA-Binding Proteins; Sirolimus; Tumor Cells, Cultured

Topics: Animals; Cyclophosphamide; Cyclosporine; Graft Rejection; Graft Survival; Haplorhini; Immunosuppressive Agents; Kidney Transplantation; Liver Transplantation; Lymphoma; Mycophenolic Acid; Papio; Polyenes; Sirolimus; Transplantation, Heterologous

Lactogens [prolactin (Prl) and growth hormone] stimulate phosphorylation of the 40S ribosomal protein, S6, in Nb2 cells by mechanisms that do not involve participation of cAMP or protein kinase A, protein kinase C, or cGMP-dependent protein kinase. However, inhibition of tyrosine kinase (TK) abrogates Prl-mediated macromolecular biosynthesis. Inasmuch as lactogen signaling may involve sequential activation of protein kinases, the effect of Prl on the well-characterized mitogen-activated protein kinase (MAPK) and S6 kinase (S6K), the enzyme responsible for S6 phosphorylation in vivo, and their relationship to Nb2 macromolecular biosynthesis and mitogenesis were investigated. The results show that MAPK stimulation is transient (peak activity, 30 min) and precedes that of S6K, which reaches a maximum at 1.5-2 h, and slowly returns towards control levels at 6 h. Both staurosporine which inhibits GH receptor-associated kinase (JAK2) and genistein (GEN), an inhibitor of membrane-associated and cytoplasmic TKs, abrogate Prl-stimulated TK, MAPK, and S6K. Rapamycin (RAP), a specific inhibitor of p70S6K, completely blocks S6K but does not affect TK and MAPK. TK and MAPK activity correlates with Prl-stimulated anabolism, i.e., protein and DNA synthesis and mitogenesis. Thus, concentrations of STR and GEN which abrogate TK and MAPK inhibit anabolism virtually 100%. However, RAP, which inhibits S6K (ca. 100%) but not TK or MAPK, only delays Prl-mediated anabolism. These results indicate that Prl signaling in Nb2 cells involves a protein kinase cascade and that regulation of receptor-associated kinase, TK, and MAPK correlates with anabolism. The role of S6K (and S6 phosphorylation) appears to be ancillary.

Topics: Alkaloids; Amino Acid Sequence; Animals; Calcium-Calmodulin-Dependent Protein Kinases; DNA; Genistein; Isoflavones; Janus Kinase 2; Lymphocyte Activation; Lymphoma; Molecular Sequence Data; Polyenes; Prolactin; Protein Biosynthesis; Protein Kinase Inhibitors; Protein Kinases; Protein Serine-Threonine Kinases; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Rats; Ribosomal Protein S6; Ribosomal Protein S6 Kinases; Ribosomal Proteins; Signal Transduction; Sirolimus; Staurosporine; T-Lymphocytes; Tumor Cells, Cultured