Lenalidomide improves the therapeutic effect of an interferon-α-dendritic cell-based lymphoma vaccine
The perspective of combining cancer vaccines with immunomodulatory drugs is currently regarded as a highly promising approach for boosting tumor-specific T cell immunity and eradicating residual malignant cells. The efficacy of dendritic cell (DC) vaccination in combination with lenalidomide, an anticancer drug effective in several hematologic malignancies, was investigated in a follicular lymphoma (FL) model. First, we evaluated the in vitro activity of lenalidomide in modulating the immune responses of lymphocytes co-cultured with a new DC subset differentiated with IFN-α (IFN-DC) and loaded with apoptotic lymphoma cells. We next evaluated the efficacy of lenalidomide and IFN-DC-based vaccination, either alone or in combination, in hu-PBL-NOD/SCID mice bearing established human lymphoma. We found that lenalidomide reduced Treg frequency and IL-10 production in vitro, improved the formation of immune synapses of CD8 + lymphocytes with lymphoma cells and enhanced anti-lymphoma cytotoxicity. Treatment of lymphoma-bearing mice with either IFN-DC vaccination or lenalidomide led to a significant decrease in tumor growth and lymphoma cell spread. Lenalidomide treatment was shown to substantially inhibit tumor-induced neo-angiogenesis rather than to exert a direct cytotoxic effect on lymphoma cells. Notably, the combined treatment with the vaccine plus lenalidomide was more effective than either single treatment, resulting in the significant regression of established tumors and delayed tumor regrowth upon treatment discontinuation. In conclusion, our data demonstrate that IFN-DC-based vaccination plus lenalidomide exert an additive therapeutic effect in xenochimeric mice bearing established lymphoma. These results may pave the way to evaluate this combination in the clinical ground.
KeywordsCancer vaccines Immunotherapy Lymphomas Dendritic cells Combination therapy Lenalidomide
Antibody-dependent cell cytotoxicity
Confocal laser scanning microscopy
Forkhead box P3
Granulocyte macrophage colony-stimulating factor
IFN-α-conditioned dendritic cells
Nonobese diabetic/severe combined immunodeficiency
Peripheral blood lymphocytes
Tumor necrosis factor α
The authors thank Mr. Daniele Macchia for extensive help with animal care and technical assistance in studies with xenochimeric mice.
Conception and design: SMS, CL; Development of methodology: SMS, CL, FU, IM; Acquisition of data (provided animals, acquired and managed patients, provided facilities, etc.): SMS, CL, SD, FS, PS, FU, IM, LL, MS; Analysis and interpretation of data (e.g., statistical analysis, biostatistics, computational analysis): SMS, CL, SD, FS, PS, FU; Writing, review, and/or revision of the manuscript: SMS, CL, FB; Administrative, technical, or material support (i.e., reporting or organizing data, constructing databases): SMS, CL; Study supervision: SMS, CL, FB, MCC.
The research was supported by Grants from Celgene Corporation (Stefano M. Santini) (Grant no. ITA-017) and the Italian Association for Research against Cancer (AIRC IG16891) (Filippo Belardelli).
Compliance with ethical standards
Conflict of interest
Stefano M. Santini received research funding from Celgene. All other authors declare that they have no conflict of interest. Celgene had no role in study design, data collection, data interpretation, writing of the manuscript.
All experiments utilizing PBMC from healthy donors were conducted in accordance with the ethical standards of the Ethics Committee of Istituto Superiore di Sanità and the Declaration of Helsinki. Institutional Review Board approval was not required for this kind of study. Buffy coat supply for our studies was approved by Azienda Ospedaliera Policlinico Umberto I on 24/02/2014 (aut.6802). All experiments utilizing blood samples from FL patients were conducted in accordance with the declaration of Helsinki. Study and procedures were approved by the Ethics Committee of Azienda Ospedaliera Sant’Andrea (aut.169/2011). All experiments on mice were executed in compliance with the Istituto Superiore di Sanità Service for Animal Welfare guidelines and after approval from the Italian Ministry of Health (aut. 296/2015-PR). Mice were housed according to Legislative Decree 26/2014 guideline.
PBMC were freshly isolated from peripheral blood samples of anonymous volunteer healthy donors at the Transfusion Center of of Policlinico Umberto I—University “La Sapienza”, Rome. Written informed consent was obtained from all blood donors to the use of their blood for research and scientific purposes. Blood samples from FL patients were anonymously provided by the Hematology Unit at the Azienda Ospedaliera Sant’Andrea Rome, Italy. Written informed consent was obtained from FL patients for the use of blood and lymph node specimens in IFN-DC-based vaccine researches.
NOD/SCID (NOD.CB17-Prkdcscid/NCrHsd) female mice were purchased from Envigo (Italy), used at 3–4 weeks of age.
Cell line authentication
Karpas-422 FL cell line was purchased from the cell bank Interlab Cell Line Collection (ICLC). Human K562 erythroleukemic cell line was purchased from the European Collection of Authenticated Cell Culture (ECACC). Both cell lines were authenticated by the suppliers by short tandem repeat (STR) profiling. The cell lines were initially grown and cryopreserved into multiple aliquots. All the experiments were performed with cells at low passage numbers (≤ 10).
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