Dataset Information

Biphasic Rapamycin Effects in Lymphoma and Carcinoma Treatment.

ABSTRACT: mTOR drives tumor growth but also supports T-cell function, rendering the applications of mTOR inhibitors complex especially in T-cell malignancies. Here, we studied the effects of the mTOR inhibitor rapamycin in mouse EL4 T-cell lymphoma. Typical pharmacologic rapamycin (1-8 mg/kg) significantly reduced tumor burden via direct suppression of tumor cell proliferation and improved survival in EL4 challenge independent of antitumor immunity. Denileukin diftitox (DD)-mediated depletion of regulatory T cells significantly slowed EL4 growth in vivo in a T-cell-dependent fashion. However, typical rapamycin inhibited T-cell activation and tumor infiltration in vivo and failed to boost DD treatment effects. Low-dose (LD) rapamycin (75 ?g/kg) increased potentially beneficial CD44hiCD62L+ CD8+ central memory T cells in EL4 challenge, but without clinical benefit. LD rapamycin significantly enhanced DD treatment efficacy, but DD plus LD rapamycin treatment effects were independent of antitumor immunity. Instead, rapamycin upregulated EL4 IL2 receptor in vitro and in vivo, facilitating direct DD tumor cell killing. LD rapamycin augmented DD efficacy against B16 melanoma and a human B-cell lymphoma, but not against human Jurkat T-cell lymphoma or ID8agg ovarian cancer cells. Treatment effects correlated with IL2R expression, but mechanisms in some tumors were not fully defined. Overall, our data define a distinct, biphasic mechanisms of action of mTOR inhibition at doses that are clinically exploitable, including in T-cell lymphomas. Cancer Res; 77(2); 520-31. ©2016 AACR.

SUBMITTER: Liu Y

PROVIDER: S-EPMC5286917 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Biphasic Rapamycin Effects in Lymphoma and Carcinoma Treatment.

Liu Yang Y Pandeswara Srilakshmi S Dao Vinh V Padrón Álvaro Á Drerup Justin M JM Lao Shunhua S Liu Aijie A Hurez Vincent V Curiel Tyler J TJ

Cancer research 20161013 2

mTOR drives tumor growth but also supports T-cell function, rendering the applications of mTOR inhibitors complex especially in T-cell malignancies. Here, we studied the effects of the mTOR inhibitor rapamycin in mouse EL4 T-cell lymphoma. Typical pharmacologic rapamycin (1-8 mg/kg) significantly reduced tumor burden via direct suppression of tumor cell proliferation and improved survival in EL4 challenge independent of antitumor immunity. Denileukin diftitox (DD)-mediated depletion of regulator ...[more]

PMID: 27737881

Similar Datasets

Project description:INTRODUCTION:Rapamycin, an inhibitor of the serine/threonine kinase target of rapamycin, induces G1 arrest and/or apoptosis. Although rapamycin and its analogues are attractive candidates for cancer therapy, their sensitivities with respect to growth inhibition differ markedly among various cancer cells. Using human breast carcinoma cell line MCF-7 as an experimental model system, we examined the growth-inhibitory effects of combinations of various agents and rapamycin to find the agent that most potently enhances the growth-inhibitory effect of rapamycin. METHOD:We evaluated the growth-inhibitory effect of rapamycin plus various agents, including cotylenin A (a novel inducer of differentiation of myeloid leukaemia cells) to MCF-7 cells, using either MTT assay or trypan blue dye exclusion test. The cell cycle was analyzed using propidium iodide-stained nuclei. Expressions of several genes in MCF-7 cells with rapamycin plus cotylenin A were studied using cDNA microarray analysis and RT-PCR. The in vitro results of MCF-7 cells treated with rapamycin plus cotylenin A were further confirmed in vivo in a mouse xenograft model. RESULTS:We found that the sensitivity of rapamycin to MCF-7 cells was markedly affected by cotylenin A. This treatment induced growth arrest of the cells at the G1 phase, rather than apoptosis, and induced senescence-associated beta-galactosidase activity. We examined the gene expression profiles associated with exposure to rapamycin and cotylenin A using cDNA microarrays. We found that expressions of cyclin G2, transforming growth factor-beta-induced 68 kDa protein, BCL2-interacting killer, and growth factor receptor-bound 7 were markedly induced in MCF-7 cells treated with rapamycin plus cotylenin A. Furthermore, combined treatment with rapamycin and cotylenin A significantly inhibited the growth of MCF-7 cells as xenografts, without apparent adverse effects. CONCLUSION:Rapamycin and cotylenin A cooperatively induced growth arrest in breast carcinoma MCF-7 cells in vitro, and treatment with rapamycin and cotylenin A combined more strongly inhibited the growth of MCF-7 cells as xenografts in vivo than treatment with rapamycin or cotylenin A alone, suggesting that this combination may have therapeutic value in treating breast cancer. We also identified several genes that were markedly modulated in MCF-7 cells treated with rapamycin plus cotylenin A.

Project description:BackgroundDespite recent advances in the treatment of hepatocellular carcinoma (HCC), the chemotherapy efficacy against HCC is still unsatisfactory. The mammalian target of rapamycin (mTOR) has been emerged as an important cancer therapeutic target. However, HCC cells often resistant to rapamycin because of the paradoxical activation of Akt by rapamycin. In this study, we investigated whether bortezomib could enhance the antitumor effects of rapamycin.MethodsThe effects of rapamycin and bortezomib on HCC proliferation, apoptosis, migration, and invasiveness in vitro were assessed by CCK-8 analysis, flow cytometry, Hoechst 33342 staining and transwell assays, respectively. Total and phosphorylated protein levels of Akt were detected by Western blotting. The effects of rapamycin and/or bortezomib on the mRNA expression levels of p53, p27, p21 and Bcl-2 family in HCCLM3 cells were evaluated by RT-PCR. The roles of rapamycin and bortezomib on HCC growth and metastasis in xenograft models were evaluated by tumor volumes and fluorescent signals. The effects of rapamycin and bortezomib on cell proliferation and apoptosis in vivo were test by PCNA and TUNEL staining.ResultsBortezomib synergized with rapamycin to reduce cell growth, induce apoptosis, and inhibit cell mobility in vitro. Further mechanistic studies showed that bortezomib inhibited rapamycin-induced phosphorylated Akt, which in turn enhanced apoptosis of HCC cell lines. The alteration of the mRNA expression of cell cycle inhibitors p53, p27, p21 and apoptosis associated genes Bcl-2, Bax were also involved in the synergistic antitumor effects of rapamycin and bortezomib. P53 inhibitor PFT-? significantly attenuate the effect of rapamycin and bortezomib on cell apoptosis, which indicated that the pro-apoptotic effect of rapamycin and bortezomib may be p53-dependent. Treatment of HCCLM3-R bearing nude mice with rapamycin and bortezomib significantly enhanced tumor growth inhibition (72.4%), comparing with either rapamycin- (54.7%) or bortezomib-treated mice (22.4%). In addition, the lung metastasis was significantly suppressed in mice received the combination treatment (16.6%). The combination treatment of rapamycin and bortezomib significantly inhibited tumor cell proliferation and tumor angiogenesis in vivo.ConclusionThe combination of rapamycin with bortezomib could be a novel and promising therapeutic approach to the treatment of HCC.

Project description:Primary effusion lymphoma (PEL) is caused by Kaposi's sarcoma-associated herpesvirus (KSHV). PEL has a highly active mTOR pathway, which makes mTOR a potential therapeutic target. MLN0128 is an ATP-competitive inhibitor of mTOR that has entered clinical trials for solid tumors. Our results demonstrated that MLN0128 has a greater effect on inhibiting proliferation than the allosteric mTOR inhibitor rapamycin. MLN0128 has ∼30 nM 50% inhibitory concentration (IC50) across several PEL cell lines, including PEL that is resistant to conventional chemotherapy. MLN0128 induced apoptosis in PEL, whereas rapamycin induced G1 arrest, consistent with a different mechanism of action. MLN0128 inhibited phosphorylation of mTOR complex 1 and 2 targets, while rapamycin only partially inhibited mTOR complex 1 targets. PEL xenograft mouse models treated with MLN0128 showed reduced effusion volumes in comparison to the vehicle-treated group. Rapamycin-resistant (RR) clones with an IC50 for rapamycin 10 times higher than the parental IC50 emerged consistently after rapamycin exposure as a result of transcriptional adaptation. MLN0128 was nevertheless capable of inducing apoptosis in these RR clones. Our results suggest that MLN0128 might offer a new approach to the treatment of chemotherapy-resistant PEL.IMPORTANCE Primary effusion lymphoma (PEL) is an aggressive and incurable malignancy, which is usually characterized by lymphomatous effusions in body cavities without tumor masses. PEL has no established treatment and a poor prognosis, with a median survival time shorter than 6 months. PEL usually develops in the context of immunosuppression, such as HIV infection or post-organ transplantation. The optimal treatment for PEL has not been established, as PEL is generally resistant to traditional chemotherapy. The molecular drivers for PEL are still unknown; however, PEL displays a constitutively active mammalian target of rapamycin (mTOR) pathway, which is critical for metabolic and cell survival mechanisms. Therefore, the evaluation of novel agents targeting the mTOR pathway could be clinically relevant for the treatment of PEL.

Dataset Information

Biphasic Rapamycin Effects in Lymphoma and Carcinoma Treatment.

Publications

Biphasic Rapamycin Effects in Lymphoma and Carcinoma Treatment.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets