Fusions Of Cells Research Articles

Human Multi-Chimeric Cell (HMCC) Therapy as a Novel Approach for Tolerance Induction in Transplantation

Cellular therapies are regarded as the most promising approach for inducing transplant tolerance without life-long immunosuppression in solid organ and vascularized composite allotransplantation (VCA). Currently, no therapies are achieving this goal. This study introduces a novel Human Multi-Chimeric Cell (HMCC) line created by fusion of umbilical cord blood (UCB) cells, from three unrelated donors as an alternative therapeutic approach to bone marrow transplantation and tolerance induction in solid organ and VCA transplants. We performed eighteen ex vivo polyethylene glycol mediated fusions of human UCB cells from three unrelated donors to create HMCC. Mononuclear cells labeled with PKH26, PKH67, and eFluor™ 670 fluorescent dyes were fused and sorted creating a new population of triple-labeled (PKH26/PKH67/eFluor™ 670) HMCC. The creation of HMCC from three unrelated human UCB donors was confirmed by flow cytometry and confocal microscopy. Genotyping analyses determined the tri-chimeric state of HMCC by presence of parent alleles and selected loci specific for each of three UCB donors. Phenotype characterization confirmed hematopoietic markers distribution, comparable to UCB donors. HMCC maintained viability and displayed a low apoptosis level. The COMET assay revealed absence of genotoxicity, confirming fusion safety. Colony forming units assay showed clonogenic properties of HMCC. This study confirmed the feasibility of HMCC creation from three unrelated human UCB donors and characterized tri-chimeric state, hematopoietic phenotype, viability, safety, and clonogenic properties of HMCC. The created HMCC line, representing genotype characteristics of three unrelated human UCB donors, introduces a novel therapeutic approach for bone marrow, solid organ, and VCA transplants.Graphical

Sequential monitoring of tumor macrophage fusion cells in the circulation of metastatic breast cancer and their prognostic value.

3054 Background: Tumor Macrophage Fusion Cells (TMFCs) are hybrids fusions of tumor cells and macrophage/immune cells that have recently been documented in advanced solid tumors, such as metastatic Breast Cancer (mBC). Further, TMFCs are found in the blood of patients (pts) as a CD45+/CD14+ binucleated subtype of standard circulating tumor cells (CTCs), which are Cytokeratin+ (CK+) & CD45 negative, but distinct from highly hyperploidy cells known as cancer associated macrophage-like cells. However, no study has explored the clinical meaning of TMFCs in blood. To better elucidate the clinical meaning of TMFCs, we prospectively pooled 137 mBC pt samples prior to induction of new therapy, ie baseline (BL), and after therapy induction (FU). Both TMFCs or standard CTCs were identified and enumerated to analyze their prognostic value for progression-free survival (PFS) and overall survival (OS). Methods: In this prospective study, we collected 7.5 mL blood samples from n=137 mBC pts enrolled in prospective trials from multiple institutions before starting new treatment lines for newly progressive mBC. If possible, an optional FU sample was collected (n=73) after BL (median=4.9 weeks). TMFCs & CTCs were isolated using a CellSieve microfilter and differentiated by staining for CK, CD45, CD14, and DAPI. Cox proportional regression hazard ratios (HRs) with 95% Confidence Intervals (CI) for PFS & OS by univariate & multivariate analyses were based on RECIST v1.1, determined by local institutional pathologist over 24 months (M). Results: TMFCs were detected in 26.3% (n=36/137) at BL and associated with significantly worse PFS (HR=3.3, CI 1.9-5.7, p<0.001) & OS (HR=2.7, CI 1.4-5.1, p=0.005). TMFCs were also detected in 27.4% (n=20/73) at FU (n=73) and prognostic for PFS (HR=5.2, CI 2.3-11.9, p<0.001) & OS (HR=5.1, 1.8-14.2, p=0.004). Further, pts with increases in TMFCs between BL and FU had worse PFS (HR=4.3, CI 1.9-10.1, p=0.001) & OS (HR=4.5, CI 1.6-12.7, p=0.011). In contrast, pts with CTCs were found in 39.4% (n=54/137) at BL, which were prognostic for worse PFS (HR=2.0, CI 1.3-3.2, p=0.005) and not prognostic for OS (HR=1.7, CI 0.9-3.0, p=0.103). At FU, pts with CTCs were found in 38.4% (n=28/73), which were prognostic for worse PFS (HR=3.6, CI 1.8-7.3, p=0.001) & OS (HR=3.2, CI 1.3-8.0, p=0.021). Overall at BL, pts without CTCs or TMFCs had a 5.7 M mPFS & >24M mOS, CTCs alone had a 5.0 M mPFS & 20.3 M mOS, TMFCs had 2.0 M mPFS & 5.8 M mOS. At FU, pts without CTCs or TMFCs had a 5.8 M mPFS & 14.5 M mOS, CTCs alone had a 3.3 M mPFS & 14.6 M mOS, while TMFCs pts had a 1.7 M mPFS & 4.8 M mOS. Conclusions: TMFCs appear to represent a CTC subgroup with additional prognostic value to standard CTCs, that may correlate with significantly faster PFS and OS versus pts with CTCs alone, or without CTCs. Subtyping treatment regimens is ongoing to determine if the TMFC populations are responsive to specific therapy types in these mBC pts.

IMT-1 PROS AND CONS OF SURGICAL INTERVENTION FOR DIFFUSE MIDLINE GLIOMA AIMED AT DENDRITIC CELL IMMUNOTHERAPY

Abstract Since a diffuse midline glioma (DMG) has no effective therapy, it is an urgent need to develop new therapeutic strategy. We performed immunotherapy using fusions of autologous dendritic cells (DC) with tumor cells in DMG cases in which tumor tissue was collected by surgery aimed at biopsy, and evaluate the effectiveness and examine the pros and cons of surgical intervention against DMG. Among the patients with basal ganglia or brain stem tumors received surgery at our hospital, 5 adult cases of DMG with H3K27M gene mutation were registered. All patients received radiation therapy and temozolomide chemotherapy. 4 cases received bevacizumab chemotherapy when the patients had recurrence or progression of the disease. The tumor-fused DCs (TFDC) were made by DCs induced from autologous peripheral blood mononuclear cells and tumor cells established from surgical specimens. They were injected subcutaneously into the neck 3 ~ 6 times in a 14 ~ 28 day cycle as the immunotherapy. The adverse events, PFS, and OS were evaluated. A transient complication of facial numbness was observed in one case on right after surgery. Although two patients had CR in those therapies, both of them died of disease (OS at 18 and 32 months, respectively). Since the remaining three cases were registered very recently, adverse event or treatment efficacy judgment have not been determined at the time of submission of the abstract. Serious surgical complications have not been observed in the presented cases. Surgery may be acceptable for DMG as long as the surgery is performed by sufficiently experienced surgeon in an appropriate environment. The TFDC immunotherapy, which can be performed only by collecting a small amount of tumor tissue, expects to be a novel treatment for MDG. In this presentation, the pros and cons of surgical intervention aimed at TFDC immunotherapy for DMG will be examined.

IMT-1 A translational research for practical use of dendritic cell-based immunotherapy against malignant glioma

Background: Although a therapeutic effect of dendritic cell (DC)-based immunotherapy, a kind of regenerative medicine, has been recognized in various types of cancer including malignant glioma, it is still impractical because of several unsolved problems. This study is aimed to solve the problems in regenerative medicine through a clinical trial of immunotherapy using fusions of DCs and glioma cells (GCs) against malignant glioma, and to put it into practical use. Methods: Primary cultured GCs and glioma stem cells (GSCs) were generated from surgical specimens of patient. DCs were generated from PBMC of same patient, and were fused with GCs and GSCs. The entire process of cell production must be performed by pairs of two cell-culture operators in a dedicated cell processing facility. We developed a remote cell-observation system for reducing hands work of operators. As a project to establish a preservation method, cryopreservation of glioma tissues, GCs/GSCs, DCs and fusion cells followed by their viability examination. Results: The remote cell-observation system worked stable in morphological observation and cell-counting for adhesion cells. A growth curve was also automatically and accurately created. Although a morphological observation of floating cells such as GSCs and DCs was possible, there was some error in counting of those cells. A project to establish a preservation method is currently underway, including the development of storage containers and storage liquids. Conclusions: Although the remote cell-observation system required some modifications at the observation site, depth of focus, etc. for floating cells, there was no problem in accuracy for adhesion cells compared with operator’s observation. This system, which can be easily installed at low cost, seemed to be helpful for practical use of regenerative medical products including this therapy. We are working on a project to establish a stable transportation and preservation method for prevalence of this treatment.

Synergism between CAR-T Cells and a Personalized Tumor Vaccine in Hematological Malignances

Synergism between CAR-T Cells and a Personalized Tumor Vaccine in Hematological Malignances

Studying divergence in human–chimp hybrid cells

Fusions of human and chimp iPS cells help study how divergence in gene expression affects phenotypic traits.

IMMU-12. PHASE I/II TRIAL OF IMMUNOTHERAPY WITH FUSIONS OF DENDRITIC CELLS AND TUMOR CELLS FOR RELAPSED OR REFRACTORY BRAIN TUMORS IN CHILDREN AND YOUNG ADULTS

BACKGROUND/OBJECTIVESRelapsed or refractory brain tumors in childhood continue to have a dismal prognosis in spite of intensive multidisciplinary treatment. Cancer immunotherapy is newly developed to be expected as next promising treatment for highly aggressive pediatric cancer. This trial was designed to evaluate the safety and effectiveness of an immunotherapy with fusions of dendritic cells (DCs) and tumor cells in patients with malignant brain tumors.METHODSPatients with histopathologically confirmed malignant and recurrent/refractory brain tumor were eligible for this immunotherapy trial. Autologous cultured tumor cells obtained from surgical specimens were fused with autologous DCs using polyethylene glycol. The fusion cells (FC) were inoculated intradermally in the cervical region and repeated 3–10 times in each 28–84 days cycle. Treatment-related toxicity, progression-free survival (PFS), and overall survival (OS) were evaluated.RESULTSSix patients were enrolled, three with high grade glioma and three with ependymoma. Median age at first course of immunotherapy was 10 years (range 8–25 years) and median follow-up time from the first course of immunotherapy was 13.5 months (range 3–33 months). All patients with immunotherapy were well tolerated to this treatment with no adverse events except local erythema in injected site. Median progression free survival and overall survival were 18 months and 18.5 months, respectively.CONCLUSIONSFC immunotherapy with autologous DCs and tumor cells for brain tumor in children and young adults were extremely well tolerated and showed encouraging responses in this series. Further phase II study of FC immunotherapy is planned to improve survival and reduce treatment related morbidity.

PEDT-03 A clinical trial of dendritic cell-based immunotherapy for refractory brain tumors in children

Background/Objectives: Relapse or refractory brain tumor in childhood continue to have a dismal prognosis in spite of developing multidisciplinary treatment. Cancer immunotherapy is newly expected as next promising treatment for highly aggressive pediatric cancer. This trial was designed to evaluate the safety and clinical responses to an immunotherapy with fusions of dendritic cells (DCs) and tumor cells in patients with malignant brain tumors. Design/Methods: Patients with histopathologically confirmed high-grade or recurrent brain tumor were eligible for our immunotherapy. Autologous cultured tumor cells obtained from surgical specimens were fused with autologous DCs using polyethylene glycol. The fusion cells (FC) were inoculated intradermally in the cervical region and repeated 3–10 times in each 28–84 days cycle. Toxicity, progression-free survival (PFS), and overall survival (OS) of this trial were evaluated. Results: Six patients were enrolled, three with high grade glioma and three with ependymoma. Median age at first course of immunotherapy was 10 years (range 8–25 years) and median time of follow-up from first course of immunotherapy was 13.5 months (range 3–33 months). All patients with immunotherapy were well tolerated and no adverse event without local erythema in injected site. Median progression free survival and overall survival were 18 months and 18.5 months, respectively. Conclusions: FC immunotherapy with autologous DCs and tumor cells for brain tumor in children and young adults were extremely well tolerated and encouraging. Further phase II study of FC immunotherapy is planned to improve prognosis and overcome treatment related neurological sequelae for highly malignant tumors.

IMT-01 THERAPEUTIC EFFECT AGAINST LOWER GRADE GLIOMA INDUCED BY DENDRITIC CELL BASED IMMUNOTHERAPY

BACKGROUNDThis trial was designed to evaluate the safety and clinical responses to an immunotherapy with fusions of dendritic and glioma cells in patients with lower grade glioma (LGG; WHO grade II-III glioma).METHODAutologous cultured glioma cells obtained from surgical specimens were fused with autologous dendritic cells (DC) using polyethylene glycol. The fusion cells (FC) were inoculated intradermally in the cervical region of subjects. Toxicity, progression-free survival (PFS), overall survival (OS), and MRI findings were evaluated. DNA for whole exome and RNA for whole transcriptome extracted from HLA-A*24:02 positive glioma cells were analyzed by next generation sequencer. Variant peptides showing strong binding affinity to HLA-A*24:02 but not the corresponding wild type peptides were selected as candidate of neo-antigens.RESULTSThe number of subjects of this trial were 24 (initially diagnosed cases: 20, recurrence cases: 4). WHO grade III cases were 20, and grade II cases were 4. Male were 15, and female were 9. Mean of follow up periods were 53.0 months (the longest follow up period: 1322 months). The number of events on PFS and OS were 8 and 6, respectively. Mean of candidate of neo-antigen peptides in HLA-A*24:02 positive patients (n=8) was 34. Among these candidates, twelve types of common neo-antigen peptide were identified. Neo-antigen peptides specifically expressed in the glioma cells from the effective group were not identified.CONCLUSIONSThese results indicate that the efficacy of FC-immunotherapy may not always depend on the number of gene mutations or the expression of the specific neo-antigens. FC-immunotherapy, as a means of producing specific immunity against neo-antigens may safely induce anti-tumor effects in patients with LGG. Analysis of prognostic factor in glioma immunotherapy may be the next area of major interest.

Adeylithon bosencei gen. et sp. nov. (Corallinales, Rhodophyta): a new reef-building genus with anatomical affinities with the fossil Aethesolithon.

Adeylithon gen. nov. with one species, A.bosencei sp. nov., belonging to the subfamily Hydrolithoideae is described from Pacific coral reefs based on psbA sequences and morpho-anatomy. In contrast with Hydrolithon, A.bosencei showed layers of large polygonal "cells," which resulted from extensive lateral fusions of perithallial cells, interspersed among layers of vegetative cells. This anatomical feature is shared with the fossil Aethesolithon, but lacking DNA sequences from the fossils and the fragmentary nature of Aethesolithon type material, wecannot ascertain if Adeylithon and Aethesolithon arecongeneric. Morpho-anatomical features of A.bosencei were generally congruent with diagnostic features of the subfamily Hydrolithoideae: (i) outline of cell filaments entirely lost in large portions due to pervasive and extensive cell fusions, (ii) trichocytes not arranged in tightly packed horizontal fields, (iii) basal layer without palisade cells, and (iv) cells lining the canal pore oriented more or less perpendicular to roof surface and not protruding into the canal. However, it showed a predominant monomerous thallus organization and trichocytes were disposed in large pustulate, horizontal fields, although they were not tightly packed and did not become distinctly buried in the thallus. Only mature tetrasporangial conceptacles were observed, therefore the type of conceptacle roof formation remained undetermined. Adeylithon bosencei occurs on shallow coral reefs, in Australia, Papua New Guinea, and South Pacific islands (Fiji, Vanuatu). Fossil Aethesolithon is considered an important component of shallow coral reefs since the Miocene; fossil records showed a broad Indo-Pacific distribution, but a long-term process of range contraction in the last 2.6 million years, resulting in an overlap with the distribution of the extant Adeylithon. While the congeneric nature of extant and fossil taxa remained uncertain, similarities in morpho-anatomy, habitat, and distribution may indicate that both taxa likely shared a common ancestor.

Phase I/II Trial of Combination of Temozolomide Chemotherapy and Immunotherapy With Fusions of Dendritic and Glioma Cells in Patients With Glioblastoma.

Phase I/II Trial of Combination of Temozolomide Chemotherapy and Immunotherapy With Fusions of Dendritic and Glioma Cells in Patients With Glioblastoma.

Fusions of Tumor-derived Endothelial Cells with Dendritic Cells Induces Antitumor Immunity

To explore dendritic cells/tumor-derived endothelial cells (DC/EC) fusion cells are potent stimulators of T cells to impact tumor progression. ECs were isolated from mice hepatoma cell line (H22) Xenograft, and dendritic cells were isolated from bone marrow of BALB/c mice, then the isolated ECs were cultured and detected the endothelial surface expression of CD105 by flow cytometry. The endothelial characteristics of ECs were detected by tube formation assay and Dil-Ac-LDL uptake assay. After the fusion with polyethylene glycol (PEG), we used DCs, ECs, DCs mixed ECs as the control groups, DC/EC fusion cells as the experimental group, Secretion of IFN-α and IFN-γ was evaluated, T lymphocyte proliferation and cytotoxic T lymphocytes (CTL) were detected in vitro. In vivo, T lymphocyte induced by five groups was injected to detect the effect of tumor progression. Purified ECs (CD105+) took the function of endothelial cells, then successfully fused with DCs. The DC/EC fusion cells were functional in stimulating the proliferation of T cells, which produced IFN-α and IFN-γ. In vivo, T cells stimulated by DC/EC fusion cells effectively repressed tumor growth. The fusion cells, which was capable of stimulating T cells, is indispensable for antitumor immunity.

Abstract 3317: Radiation induced multinucleated giant cells: A novel therapeutic target to prevent survival and relapse of glioblastoma

Abstract In this study, we address the fundamental issue of radiation resistance in Glioblastoma Multiforme (GBM) a highly malignant form of brain tumor. However, because of the unavailability of multiple biopsies of GBM patients after treatment, we are limited in our understanding of resistance mechanisms. To circumvent this problem we recapitulated clinical scenario of GBM resistance in a cellular model developed from fresh naive primary GBM patient samples and cell lines. Using our model we show that upon lethal dose of radiation, small percentage of GBM cells survive, are non-apoptotic and transiently become non- proliferative. They are arrested in G2/M phase of cell cycle mediated by inhibitory phosphorylation of Cdk1(Y15) and p21. Surprisingly, we find although non -proliferative, these cells are highly motile and undergo homotypic cell-cell fusions at high frequency to form multinucleated and giant cells (MNGCs). Cell fusion leads to the induction of senescence as seen by β-galactosidase staining and accordingly high expression of SASPs (senescence associated secretory proteins like GM-CSF, SCF, IL-6 and IL-8) is also observed. SASPs provide survival and proliferation signals to the cells in an autocrine manner. Accordingly, we find enhanced expression of anti-apoptotic genes BIRC3 and Bcl-xL and unaltered levels of Bax (pro-apoptotic protein) mRNA in the resistant cells. MNGCs also activate AKT, which is a survival signal and a central convergence node of signals downstream to SASPs. AKT activation along with Bcl-xL is reported to regulate apoptosis synergistically. Additionally, resistant cells also undergo active DNA damage repair mediated by sensory kinases ATM and ATR. Interestingly, irrespective of the phase of cell cycle, they adopt Non Homologous End Joining (NHEJ) as their pathway of choice to repair their double strand breaks in DNA. Since we find increased presence of H3K36me2 marks known to modulate NHEJ, a possible link between NHEJ and this modification in GBM is worth exploring. Finally, unlike previous reports we demonstrate that MNGCs do not die of mitotic catastrophe instead escape senescence, undergo normal cell division and proliferation giving rise to mono-nucleated relapse cells with unaltered ploidy compared to parent cells. Importantly, we also show the potential ability to prevent the relapse in Glioma by disrupting the non-proliferative state of radiation resistant cells using mitotic inducer (MK1775) and selectively ablating growth of MNGCs by cytokinesis inhibitor. In summary, our data provides a mechanistic explanation for clinical observations and novel insights into an unexplored multi-step process of radiation survival and relapse in Glioblastoma We identified homotypic cell fusions of resistant Glioma cells as a novel non-genetic mechanism to sustain survival and relapse and generate rationale for novel combinatorial targeted therapies. Citation Format: Ekjot Kaur, Jacinth Rajendra, Sanket Shah, Jyothi Nair, Ankit Khushwaha, Aliasgar Moiyadi, Shilpee Dutt. Radiation induced multinucleated giant cells: A novel therapeutic target to prevent survival and relapse of glioblastoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3317. doi:10.1158/1538-7445.AM2015-3317

Dendritic cell-glioma fusion activates T lymphocytes by elevating cytotoxic efficiency as an antitumor vaccine.

BackgroundHybrid cells produced by fusions of tumor and dendritic cells (DC) have demonstrated remarkable efficacy for priming the anti-tumor immune response. In the current study, we examined the antitumor activity of cytotoxic T lymphocytes (CTLs) primed in response to a tumor vaccine comprising a glioma-DC fusion as part of a therapeutic against glioma.Material and methodsPrimary cultured glioma cells were fused with peripheral blood DC under conditions of polyethylene glycol (PEG) incubation. Glioma cell suspensions were designated as three groups to include (1) CTL-effective cell group activated by fused cells; (2) CTL-effective cell group stimulated by co-cultured glioma cells and DC cells; and (3) lymphocyte-only group as a control, which was not stimulated by the DC. Cytotoxicity of CTLs on glioma cells was accessed by MTT assay in vitro.ResultsGlioma cells with peripheral blood DC were cultured and fused. The killing effect of CTLs pre-activated by fused cells was significantly higher than that of the co-culture CTL group with unsensitized lymphocytes (p < 0.01). The killing activity, as measured by an enhanced efficiency ratio, was increased significantly in the co-cultures of fused cells with CTL groups (p < 0.01).ConclusionsThe glioma-dendritic cell fusion vaccine possessed a more effective anticancer activity by stimulating the effector activity of CTLs.

Immunotherapy of Radioresistant Mammary Tumors with Early Metastasis Using Molecular Chaperone Vaccines Combined with Ionizing Radiation

In the current study, exposure of mammary tumor cells derived from mice transgenic for the polyomavirus middle T oncogene to ionizing radiation resulted in the generation of a tumor cell population that preferentially expressed cancer stem cell markers. In addition, these cells were more resistant to subsequent radiation treatments and appeared to acquire an enhanced capacity for dissemination to the lungs of mice. Therefore, we tested an immunotherapy approach to the treatment of local and disseminated mammary tumor cells in a murine model using a recently developed molecular chaperone-based vaccine that specifically targets the radioresistant subpopulation of tumor cells. Heat shock protein 70-peptide complexes (Hsp70.PC-F) were extracted from fusions of dendritic cells and radiation-enriched tumor cells, and the resulting chaperone vaccines were used to treat mice with pre-existing lung metastases. Immunization of mice with the Hsp70.PC-F vaccine resulted in a T cell-mediated immune response, including a significant increase in CD4 and CD8 T cell proliferation and the induction of effector T cells capable of targeting radioresistant tumor cells. Importantly, the growth of primary tumors was inhibited, and the number of tumor cells metastasizing to lung was reduced significantly by combining chaperone vaccine with radiotherapy. These results indicate that Hsp70.PC-F vaccine can induce specific immunity to radioresistant populations of mammary tumor cells and, thus, can complement radiotherapy, leading to synergistic killing.

Augmentation of Antitumor Immunity by Fusions of Ethanol-Treated Tumor Cells and Dendritic Cells Stimulated via Dual TLRs through TGF-β1 Blockade and IL-12p70 Production

The therapeutic efficacy of fusion cell (FC)-based cancer vaccine generated with whole tumor cells and dendritic cells (DCs) requires the improved immunogenicity of both cells. Treatment of whole tumor cells with ethanol resulted in blockade of immune-suppressive soluble factors such as transforming growth factor (TGF)-β1, vascular endothelial growth factor, and IL-10 without decreased expression of major histocompatibility complex (MHC) class I and the MUC1 tumor-associated antigen. Moreover, the ethanol-treated tumor cells expressed “eat-me” signals such as calreticulin (CRT) on the cell surface and released immunostimulatory factors such as heat shock protein (HSP)90α and high-mobility group box 1 (HMGB1). A dual stimulation of protein-bound polysaccharides isolated from Coriolus versicolor (TLR2 agonist) and penicillin-inactivated Streptococcus pyogenes (TLR4 agonist) led human monocyte-derived DCs to produce HSP90α and multiple cytokines such as IL-12p70 and IL-10. Interestingly, incorporating ethanol-treated tumor cells and TLRs-stimulated DCs during the fusion process promoted fusion efficiency and up-regulated MHC class II molecules on a per fusion basis. Moreover, fusions of ethanol-treated tumor cells and dual TLRs-stimulated DCs (E-tumor/FCs) inhibited the production of multiple immune-suppressive soluble factors including TGF-β1 and up-regulated the production of IL-12p70 and HSP90α. Most importantly, E-tumor/FCs activated T cells capable of producing high levels of IFN-γ, resulting in augmented MUC1-specific CTL induction. Collectively, our results illustrate the synergy between ethanol-treated whole tumor cells and dual TLRs-stimulated DCs in inducing augmented CTL responses in vitro by FC preparations. The alternative system is simple and may provide a platform for adoptive immunotherapy.

In vitro evaluation of human hybrid cell lines generated by fusion of B-lymphoblastoid cells and ex vivo tumour cells as candidate vaccines for haematological malignancies

Fusions of dendritic cells (DCs) and tumour cells have been shown to induce protective immunity to tumour challenge in animal models, and to represent a promising approach to cancer immunotherapy. The broader clinical application of this approach, however, is potentially constrained by the lack of replicative capacity and limited standardisation of fusion cell preparations. We show here that fusion of ex vivo tumour cells isolated from patients with a range of haematological malignancies with the human B-lymphoblastoid cell line (LCL), HMy2, followed by chemical selection of the hybridomas, generated stable, self-replicating human hybrid cell lines that grew continuously in tissue culture, and survived freeze/thawing cycles. The hybrid cell lines expressed HLA class I and class II molecules, and the major T-cell costimulatory molecules, CD80 and CD86. All but two of 14 hybrid cell lines generated expressed tumour-associated antigens that were not expressed by HMy2 cells, and were therefore derived from the parent tumour cells. The hybrid cell lines stimulated allogeneic T-cell proliferative responses and interferon-gamma release in vitro to a considerably greater degree than their respective parent tumour cells. The enhanced T-cell stimulation was inhibited by CTLA4-Ig fusion protein, and by blocking antibodies to MHC class I and class II molecules. Finally, all of five LCL/tumour hybrid cell lines tested induced tumour antigen-specific cytotoxic T-cell responses in vitro in PBL from healthy, HLA-A2+ individuals, as detected by HLA-A2-peptide pentamer staining and cellular cytotoxicity. These data show that stable hybrid cell lines, with enhanced immunostimulatory properties and potential for therapeutic vaccination, can be generated by in vitro fusion and chemical selection of B-LCL and ex vivo haematological tumour cells.

Long-lived fusions of human haematological tumour cells and B-lymphoblastoid cells induce tumour antigen-specific cytotoxic T-cell responses in vitro

Tumour-specific cytotoxic T-cells (CTL) are important anti-cancer immune effectors. Most tumour cells, however, do not stimulate effective anti-tumour immune responses, in vivo or in vitro. To enhance tumour cell immunogenicity, we fused human tumour cells from haematological malignancies with the B-lymphoblastoid cell line (LCL), HMy2, to generate a panel of long-lived, self replicating LCL/tumour hybrid cell lines. The LCL/tumour hybrid cell lines expressed HLA class I and class II molecules, CD80 and CD86, and a range of known tumour associated antigens (TAAs). In vitro stimulation of PBLs from healthy, HLA-A2+ individuals by hybrid cell lines induced tumour antigen-specific CTLs to TAAs, including survivin, MAGE-A1, NY-ESO-1 and WT-1. Individual hybrid cell lines simultaneously induced CTL to multiple TAAs. In vitro stimulation of PBL from 2 patients with acute myeloid leukaemia by autologous LCL/tumour hybrid cell lines induced CTL capable of killing the patient's own tumour cells. Our data show, for the first time, that hybrid cell lines formed by fusion of HMy2 cells and haematological tumour cells induce tumour- and tumour antigen-specific cytotoxic T-cell responses in vitro. Hybrid cell lines such as those described may represent novel reagents for use in the immunotherapy of haematological malignancies.

Semiallogenic fusions of MSI+tumor cells and activated B cells induce MSI-specific T cell responses

BackgroundVarious strategies have been developed to transfer tumor-specific antigens into antigen presenting cells in order to induce cytotoxic T cell responses against tumor cells. One approach uses cellular vaccines based on fusions of autologous antigen presenting cells and allogeneic tumor cells. The fusion cells combine antigenicity of the tumor cell with optimal immunostimulatory capacity of the antigen presenting cells.Microsatellite instability caused by mutational inactivation of DNA mismatch repair genes results in translational frameshifts when affecting coding regions. It has been shown by us and others that these mutant proteins lead to the presentation of immunogenic frameshift peptides that are - in principle - recognized by a multiplicity of effector T cells.MethodsWe chose microsatellite instability-induced frameshift antigens as ideal to test for induction of tumor specific T cell responses by semiallogenic fusions of microsatellite instable carcinoma cells with CD40-activated B cells. Two fusion clones of HCT116 with activated B cells were selected for stimulation of T cells autologous to the B cell fusion partner. Outgrowing T cells were phenotyped and tested in functional assays.ResultsThe fusion clones expressed frameshift antigens as well as high amounts of MHC and costimulatory molecules. Autologous T cells stimulated with these fusions were predominantly CD4+, activated, and reacted specifically against the fusion clones and also against the tumor cell fusion partner. Interestingly, a response toward 6 frameshift-derived peptides (of 14 tested) could be observed.ConclusionCellular fusions of MSI+ carcinoma cells and activated B cells combine the antigen-presenting capacity of the B cell with the antigenic repertoire of the carcinoma cell. They present frameshift-derived peptides and can induce specific and fully functional T cells recognizing not only fusion cells but also the carcinoma cells. These hybrid cells may have great potential for cellular immunotherapy and this approach should be further analyzed in preclinical as well as clinical trials. Moreover, this is the first report on the induction of frameshift-specific T cell responses without the use of synthetic peptides.

The Efficiency of Cell Fusion-Based Reprogramming Is Affected by the Somatic Cell Type and theIn VitroAge of Somatic Cells

Cell fusion is one approach that has been used to demonstrate nuclear reprogramming of somatic cells to a pluripotent-like state and is a useful tool for screening factors involved in reprogramming. Recent cell fusion studies reported that the overexpression of Nanog and SalI could improve the efficiency of reprogramming, whereas AID was shown to be essential for DNA demethylation and initiation of reprogramming. The aim of this study was to investigate factors affecting the reprogramming efficiency following cell fusion. We conducted fusions of mouse embryonic stem cells (ESCs) with somatic cells carrying a GFP transgene under control of the Oct4 promoter (Oct4-GFP), which is normally repressed in nonpluripotent cells. The effect of somatic cell type on the reprogramming efficiency was investigated using Oct4-GFP expression as an indicator. Different somatic cell types were tested including mesenchymal stem cells (MSCs), adipose tissue-derived cells (ADCs), neural stem cells (NSCs), and these were compared with the mouse embryonic fibroblast (mEF) standard. The reprogramming efficiencies differed greatly, with mEFs (0.477 ± 0.003%) and MSCs (0.313 ± 0.003%) showing highest efficiencies while NSCs (0.023 ± 0.014%), and ADCs (0.006 ± 0.006%) had significantly lower reprogramming efficiencies (p < 0.05). The differences in the reprogramming efficiencies observed could be in part explained by the in vitro age of the somatic cells used. We demonstrated that the reprogramming efficiency of early passage mEFs was significantly higher compared with late passage mEFs (0.330 ± 0.166% vs. 0.021 ± 0.011%, p < 0.05), suggesting that senescence can affect reprogramming potential. In summary, this study shows that different somatic cell types do not have equivalent potential to be reprogrammed following fusion with ESCs. Furthermore, the in vitro age of somatic cells can also affect the reprogrammability of somatic cells. These findings constitute an important consideration for reprogramming studies.