[Show abstract][Hide abstract]ABSTRACT: Treatment options are limited in well differentiated (WD) and dedifferentiated (DD) retroperitoneal liposarcoma. We sought to study the intratumoral adaptive immune response and explore the potential feasibility of immunotherapy in this disease. Tumor-infiltrating lymphocytes (TILs) were isolated from fresh surgical specimens and analyzed by flow cytometry for surface marker expression. Previously reported immune cell aggregates known as tertiary lymphoid structures (TLS) were further characterized by immunohistochemistry. In all fresh tumors, TILs were found. The majority of TILs were CD4 T cells; however cytotoxic CD8 T cells were also seen (average: 20% of CD3 T cells). Among CD8 T cells, 65% expressed the immune checkpoint molecule PD-1. Intratumoral TLS may be sites of antigen presentation as DC-LAMP positive, mature dendritic cells were found juxtaposed next to CD4 T cells. Clinicopathologic correlation, however, demonstrated that presence of TLS was associated with worse recurrence-free survival in WD disease and worse overall survival in DD disease. Our data suggest that an adaptive immune response is present in WD/DD retroperitoneal liposarcoma but may be hindered by TLS, among other possible microenvironmental factors; further investigation is needed. Immunotherapy, including immune checkpoint blockade, should be evaluated as a treatment option in this disease.
[Show abstract][Hide abstract]ABSTRACT: T-cell receptor–α (TCRα) rearrangement in CD4+CD8+ double-positive immature thymocytes is a prerequisite for production of αβ T cells and invariant natural killer T cells.
This developmental event is regulated by the TCRα enhancer (Eα), which induces chromatin modification and recruitment of the
recombination-activating proteins Rag1 and Rag2. However, the molecular mechanism underlying the activation and long-range
action of Eα remains incompletely understood. We show here that the chromatin-modifying factor TRIM28 is highly expressed
in double-positive thymocytes and persistently phosphorylated at serine 473. TRIM28 binds to Eα and induces histone 3 lysine
4 trimethylation in the Eα and distant regions of the TCRα locus, coupled with recruitment of Rag proteins. T-cell–conditional
ablation of TRIM28 impaired TCRα gene rearrangement and compromised the development of αβ T cells and invariant natural killer
T cells. These findings establish TRIM28 as a unique regulator of thymocyte development and highlight an epigenetic mechanism
involving TRIM28-mediated active chromatin modification in the TCRα locus.
Full-text · Article · Dec 2012 · Proceedings of the National Academy of Sciences
[Show abstract][Hide abstract]ABSTRACT: Purpose:
Treatment of melanoma patients with selective BRAF inhibitors results in objective clinical responses in the majority of patients with BRAF-mutant tumors. However, resistance to these inhibitors develops within a few months. In this study, we test the hypothesis that BRAF inhibition in combination with adoptive T-cell transfer (ACT) will be more effective at inducing long-term clinical regressions of BRAF-mutant tumors.
BRAF-mutated human melanoma tumor cell lines transduced to express gp100 and H-2D(b) to allow recognition by gp100-specific pmel-1 T cells were used as xenograft models to assess melanocyte differentiation antigen-independent enhancement of immune responses by BRAF inhibitor PLX4720. Luciferase-expressing pmel-1 T cells were generated to monitor T-cell migration in vivo. The expression of VEGF was determined by ELISA, protein array, and immunohistochemistry. Importantly, VEGF expression after BRAF inhibition was tested in a set of patient samples.
We found that administration of PLX4720 significantly increased tumor infiltration of adoptively transferred T cells in vivo and enhanced the antitumor activity of ACT. This increased T-cell infiltration was primarily mediated by the ability of PLX4720 to inhibit melanoma tumor cell production of VEGF by reducing the binding of c-myc to the VEGF promoter. Furthermore, analysis of human melanoma patient tumor biopsies before and during BRAF inhibitor treatment showed downregulation of VEGF consistent with the preclinical murine model.
These findings provide a strong rationale to evaluate the potential clinical application of combining BRAF inhibition with T-cell-based immunotherapy for the treatment of patients with melanoma.
Full-text · Article · Nov 2012 · Clinical Cancer Research
[Show abstract][Hide abstract]ABSTRACT: Purpose:
Adoptive cell therapy (ACT) using autologous tumor-infiltrating lymphocytes (TIL) is a promising treatment for metastatic melanoma unresponsive to conventional therapies. We report here on the results of an ongoing phase II clinical trial testing the efficacy of ACT using TIL in patients with metastatic melanoma and the association of specific patient clinical characteristics and the phenotypic attributes of the infused TIL with clinical response.
Altogether, 31 transiently lymphodepleted patients were treated with their expanded TIL, followed by two cycles of high-dose interleukin (IL)-2 therapy. The effects of patient clinical features and the phenotypes of the T cells infused on the clinical response were determined.
Overall, 15 of 31 (48.4%) patients had an objective clinical response using immune-related response criteria (irRC) with 2 patients (6.5%) having a complete response. Progression-free survival of more than 12 months was observed for 9 of 15 (60%) of the responding patients. Factors significantly associated with the objective tumor regression included a higher number of TIL infused, a higher proportion of CD8(+) T cells in the infusion product, a more differentiated effector phenotype of the CD8(+) population, and a higher frequency of CD8(+) T cells coexpressing the negative costimulation molecule "B- and T-lymphocyte attenuator" (BTLA). No significant difference in the telomere lengths of TIL between responders and nonresponders was identified.
These results indicate that the immunotherapy with expanded autologous TIL is capable of achieving durable clinical responses in patients with metastatic melanoma and that CD8(+) T cells in the infused TIL, particularly differentiated effectors cells and cells expressing BTLA, are associated with tumor regression.
Full-text · Article · Oct 2012 · Clinical Cancer Research
[Show abstract][Hide abstract]ABSTRACT: T-cell receptor (TCR) variable Vα and Vβ gene diversity is a surrogate biomarker for the therapeutic potential of adoptive immunotherapy and cellular immunity. Therefore, creating a straightforward, rapid, sensitive, and reliable method to view the global changes of both TCRVα and Vβ transcripts in heterogeneous populations of T cells is appealing.
We designed a "direct TCR expression assay" (DTEA) using a panel of customized bar-coded probes that simultaneously detects and quantifies 45 Vα and 46 Vβ transcripts in a nonenzymatic digital multiplexed assay from a small number of cells (10(4) cells) or as little as 100 ng of total RNA.
We evaluated DTEA on total RNA samples of tumor-infiltrating lymphocytes and peripheral blood obtained from patients with melanoma after adoptive T-cell therapy. DTEA detected a similar spectrum of the dominant patterns of TCRVβ gene usage as sequencing cloned TCRVβ CDR3 regions. However, DTEA was rapid, achieved a level of sensitivity to identify rare T-cell populations, and simultaneously tracked the full array of Vα and Vβ transcripts.
DTEA can rapidly and sensitively track changes in TCRVα and Vβ gene usages in T-cell pools following immune interventions, such as adoptive T-cell transfer, and may also be used to assess impact of vaccination or reconstitution of T-cell compartment after hematopoietic stem cell transplantation.
Full-text · Article · Jul 2012 · Clinical Cancer Research
[Show abstract][Hide abstract]ABSTRACT: An antiviral innate immune response involves induction of type I interferons (IFNs) and their subsequent autocrine and paracrine actions, but the underlying regulatory mechanisms are incompletely understood. Here we report that CYLD, a deubiquitinase that specifically digests lysine 63-linked ubiquitin chains, is required for antiviral host defense. Loss of CYLD renders mice considerably more susceptible to infection by vesicular stomatitis virus (VSV). Consistently, CYLD-deficient dendritic cells are more sensitive to VSV infection. This functional defect was not due to lack of type I IFN production but rather because of attenuated IFN receptor signaling. In the absence of CYLD, IFN-β is ineffective in the induction of antiviral genes and protection of cells from viral infection. These findings establish CYLD as a novel regulator of antiviral innate immunity and suggest a role for CYLD in regulating IFN receptor signaling.
[Show abstract][Hide abstract]ABSTRACT: (A) Top, Lentiviral gene transfer vectors used to transduce human KG-1 cells and primary DCs. The human phosphoglycerate kinase (hPGK) promoter was used to drive the expression of WT and Δ7 isoforms of HLA-A*0201. Bottom, Predicted amino acid sequences of the cytoplasmic domains of WT and Δ7 HLA-A*0201. Exon 7-encoding amino acids are depicted as red, and bold font indicates reported phosphorylation sites. (B) Human DC-like KG-1 cells and primary CD34+-derived DCs were transduced to express comparable levels of surface HLA-A*0201, as determined by HLA-A2-specific mAb staining and flow cytometry. WT-A2, grey and blue histograms; Δ7-A2, black and green histograms. (C) FluM1-specific CD8+ T cells were expanded in vitro using WT-A2 or Δ7-A2-expressing DCs. Expanded T cells were then tested for effector function by co-incubating for 4 h with T2 cells pulsed with titrated amounts of FluM1 peptide, then stained for intracellular IFN-γ and surface CD107a. (D) Expansion of low frequency, MART-1-specific T cells from peripheral donor blood using peptide-pulsed WT-A2 or Δ7-A2-expressing KG-1 cells as stimulator cells. (E) Quantitation of the mean number of APC/T-cell clusters per culture well, as counted in a blinded fashion.
[Show abstract][Hide abstract]ABSTRACT: Dendritic cell (DC)-mediated presentation of MHC class I (MHC-I)/peptide complexes is a crucial first step in the priming of CTL responses, and the cytoplasmic tail of MHC-I plays an important role in modulating this process. Several species express a splice variant of the MHC-I tail that deletes exon 7-encoding amino acids (Δ7), including a conserved serine phosphorylation site. Previously, it has been shown that Δ7 MHC-I molecules demonstrate extended DC surface half-lives, and that mice expressing Δ7-K(b) generate significantly augmented CTL responses to viral challenge. Herein, we show that Δ7-D(b)-expressing DCs stimulated significantly more proliferation and much higher cytokine secretion by melanoma antigen-specific (Pmel-1) T cells. Moreover, in combination with adoptive Pmel-1 T-cell transfer, Δ7-D(b) DCs were superior to WT-D(b) DCs at stimulating anti-tumor responses against established B16 melanoma tumors, significantly extending mouse survival. Human DCs engineered to express Δ7-HLA-A*0201 showed similarly enhanced CTL stimulatory capacity. Further studies demonstrated impaired lateral membrane movement and clustering of human Δ7-MHC-I/peptide complexes, resulting in significantly increased bioavailability of MHC-I/peptide complexes for specific CD8+ T cells. Collectively, these data suggest that targeting exon 7-encoded MHC-I cytoplasmic determinants in DC vaccines has the potential to increase CD8+ T-cell stimulatory capacity and substantially improve their clinical efficacy.
[Show abstract][Hide abstract]ABSTRACT: (A) Top, Lentiviral gene transfer vectors used to transduce murine DCs. The mouse stem cell virus (MSCV) promoter was used to drive the expression of WT and Δ7 isoforms of H-2Db. A downstream internal ribosome entry site (IRES) allowed for the concurrent expression of green fluorescent protein (GFP). Bottom, Predicted amino acid sequences of the cytoplasmic domains of WT and Δ7 H-2Db. Exon 7-encoding amino acids are depicted as red, and bold font indicates reported phosphorylation sites. (B) WT-Db/GFP-, Δ7-Db/GFP-, or GFP-tranduced DCs were pulsed with titrated concentrations of hgp100(25–33) peptide, washed, and used to stimulate naïve Pmel-1 CD8+ T cells. Graph indicates the total number of Pmel-1 T cells present at d4 of co-culture, as quantitated by trypan blue staining. (C) Transduced DCs were pulsed with hgp100 peptide (300 nM), and co-injected along with Pmel-1 CD8+ T cells into C57BL/6 recipients. DC-mediated T-cell expansion in vivo was compared by measuring the percentage of Thy1.1+ Pmel-1 T cells in peripheral blood at different time points following adoptive transfer.
[Show abstract][Hide abstract]ABSTRACT: Oncoprotein Tax, encoded by the human T-cell leukemia virus type 1 (HTLV1), persistently induces NF-κB activation, which contributes to HTLV1-mediated T-cell transformation. Recent studies suggest that the signaling function of Tax requires its ubiquitination, although how the Tax ubiquitination is regulated remains unclear.
We show here that the deubiquitinase CYLD physically interacts with Tax and negatively regulates the ubiquitination of this viral protein. This function of CYLD is associated with inhibition of Tax-mediated activation of IKK although not that of Tak1. Interestingly, CYLD undergoes constitutive phosphorylation in HTLV1-transformed T cells, a mechanism known to inactivate the catalytic activity of CYLD. Consistently, a phospho-mimetic CYLD mutant fails to inhibit Tax ubiquitination.
These findings suggest that CYLD negatively regulates the signaling function of Tax through inhibition of Tax ubiquitination. Conversely, induction of CYLD phosphorylation may serve as a mechanism by which HTLV1 overrides the inhibitory function of CYLD, leading to the persistent activation of NF-κB.
Preview · Article · Aug 2011 · Cell and Bioscience
[Show abstract][Hide abstract]ABSTRACT: One of the most important rate-limiting steps in adoptive cell transfer (ACT) is the inefficient migration of T cells to tumors. Because melanomas specifically express the chemokines CXCL1 and CXCL8 that are known to facilitate the CXCR2-dependent migration by monocytes, our aim is to evaluate whether introduction of the CXCR2 gene into tumor-specific T cells could further improve the effectiveness of ACT by enhancing T-cell migration to tumor.
In this study, we used transgenic pmel-1 T cells, which recognize gp100 in the context of H-2Db, that were transduced with luciferase gene to monitor the migration of transferred T cells in vivo. To visualize luciferase-expressing T cells within a tumor, a nonpigmented tumor is required. Therefore, we used the MC38 tumor model, which naturally expresses CXCL1.
Mice bearing MC38/gp100 tumor cells treated with CXCR2/luciferase-transduced pmel-1 T cells showed enhanced tumor regression and survival compared with mice receiving control luciferase-transduced pmel-1 T cells. We also observed preferential accumulation of CXCR2-expressing pmel-1 T cells in the tumor sites of these mice using bioluminescence imaging. A similar enhancement in tumor regression and survival was observed when CXCR2-transduced pmel-1 T cells were transferred into mice bearing CXCL1-transduced B16 tumors compared with mice treated with control pmel-1 T cells.
These results implicate that the introduction of the CXCR2 gene into tumor-specific T cells can enhance their localization to tumors and improve antitumor immune responses. This strategy may ultimately enable personalization of cancer therapies based on chemokine expression by tumors.
Full-text · Article · Oct 2010 · Clinical Cancer Research
[Show abstract][Hide abstract]ABSTRACT: Mucosal dendritic cells have been implicated in the capture, storage, and transmission of HIV to CD4(+) T cells as well as in the promotion of HIV replication in activated CD4(+) T cells during the cognate T-cell and DC interaction. We report that HIV induces human genital mucosal epithelial cells to produce thymic stromal lymphopoietin (TSLP) via activation of the NFkappaB signaling pathway. The TSLP secreted by HIV exposed epithelial cells activated DC, which promoted proliferation and HIV-1 replication of co-cultured autologous CD4(+) T cells. In rhesus macaques, we observed dramatic increases in TSLP expression concurrent with an increase in viral replication in the vaginal tissues within the first 2 weeks after vaginal SIV exposure. These data suggest that HIV-mediated TSLP production by mucosal epithelial cells is a critical trigger for DC-mediated amplification of HIV-infection in activated CD4(+) T cells. The cross talk between mucosal epithelial cells and DC, mediated by HIV-induced TSLP, may be an important mechanism for the high rate of HIV infection in women through the vaginal mucosa.
Full-text · Article · Sep 2009 · Proceedings of the National Academy of Sciences
[Show abstract][Hide abstract]ABSTRACT: Lithium is an anti-depressant drug that also possesses immunomodulatory functions. The anti-inflammatory effect of lithium is thought to involve activation of the transcription factor CREB, although the underlying mechanism is incompletely understood. We show here that in macrophages lithium stimulates Tpl2, a MAP kinase kinase kinase (MAP3K) known to mediate activation of extracellular signal regulated kinase (ERK) and the downstream target CREB. Lithium activates Tpl2 by inducing degradation of p105, an NF-kappaB precursor protein that functions as a physiological inhibitor of Tpl2. This novel function of lithium does not involve inhibition of a well-characterized lithium target, GSK3beta, since other known GSK3beta inhibitors do not induce p105 degradation or Tpl2 activation. Lithium also promotes the activation of Tpl2 and ERK by the TLR4 ligand LPS. On the other hand, prolonged incubation of macrophages with lithium results in dramatic loss of p105 and inhibition of LPS-stimulated NF-kappaB activation. Consequently, lithium both attenuates LPS-mediated pro-inflammatory gene induction and induces apoptosis in macrophages. These results provide novel insight into the anti-inflammatory function of lithium.
[Show abstract][Hide abstract]ABSTRACT: Transcription factor NF-kappaB is regulated by a family of inhibitors, IkappaBs, as well as the NF-kappaB1 and NF-kappaB2 precursor proteins, p105 and p100. Although the different NF-kappaB inhibitors can all inhibit NF-kappaB in vitro, their physiological functions are incompletely understood. In this study, we demonstrate that p105 plays an important role in the regulation of T cell homeostasis and prevention of chronic inflammation. Mice lacking p105, but expressing the mature NF-kappaB1 p50, spontaneously develop intestinal inflammation with features of human inflammatory bowel disease. This inflammatory disorder occurs under specific pathogen-free conditions and critically involves T cells. Consistently, the p105-deficient mice have reduced frequency of naive T cells and increased frequency of memory/effector T cells in the peripheral lymphoid organs. Although p105 is dispensable for the production of immunosuppressive regulatory T cells, p105 deficiency renders CD4 T cells more resistant to Treg-mediated inhibition. We further show that the loss of p105 results in hyperproduction of Th17 subset of inflammatory T cells. Together, these findings suggest a critical role for NF-kappaB1 p105 in the regulation of T cell homeostasis and differentiation and the control of chronic inflammation.
Preview · Article · Apr 2009 · The Journal of Immunology