Tumor-specific Proliferation Research Articles

Allogeneic Vδ1 gamma delta T cells engineered with glypican-3 (GPC3)-specific CAR expressing soluble IL-15 have enhanced antitumor efficacy against hepatocellular carcinoma in preclinical models.

e14511 Background: Autologous αβ chimeric antigen receptor (CAR) T cell therapy has shown promising clinical results in hematologic malignancies but limited success in solid tumors. Allogeneic αβ T cell therapy may overcome several challenges faced by autologous therapy but carries the risk of graft-versus-host disease (GvHD) and does not readily recognize multiple tumor-associated antigens. Gamma delta (γδ) T cells are highly cytolytic effectors that can recognize and kill tumor cells in an MHC-unrestricted manner without causing GvHD. The Vδ1 subset is preferentially localized in peripheral tissue and is critical for tumor immunosurveillance. Engineering Vδ1 T cells with CARs can further enhance antitumor activity and represents an attractive and safe approach to treating solid tumors. However, their clinical use has been hindered by the limited number of circulating Vδ1 T cells. Here, we describe the development of the first allogeneic Vδ1 T cells that have been expanded from healthy donor PBMCs and genetically modified to secrete IL-15 (sIL15) and express a CAR targeting glypican-3 (GPC3), a rational target for hepatocellular carcinoma (HCC). Methods: Vδ1 T cells in healthy donor PBMCs were activated by a Vδ1-specific monoclonal antibody and transduced with 41BBζ or 41BBζ-sIL15 GPC3-CARs prior to cell expansion, αβ T cell depletion and cryopreservation. In vitro characterization included: 1) co-culture assays with GPC3-expressing HCC targets HepG2 and PLC/PRF/5, 2) phenotypic analysis by flow cytometry, and 3) cytokine production by multiplexed immunoassay. For in vivo assessment of tumor control, immunodeficient NSG mice were subcutaneously injected with HepG2 cells and treated with a single dose of 41BBζ or 41BBζ-sIL15 GPC3-CAR Vδ1 T cells. Additionally, tissues were harvested 7 days post transfer and analyzed by flow cytometry for Vδ1 T cell tissue homing and proliferation, or at end of study and analyzed for GvHD by immunohistochemistry. Results: Vδ1 T cells expanded over 10,000-fold and routinely reached >80% purity. Expanded Vδ1 T cells showed a primarily naïve-like phenotype (CD45RA+CD27+) with minimal exhaustion receptor expression and displayed robust proliferation, cytokine production, and cytotoxic activity against HCC cell lines expressing low and high GPC3 levels in vitro. In a HepG2 mouse model, GPC3-CAR Vδ1 T cells primarily accumulated and proliferated in the tumor, and a single dose was able to efficiently control tumor burden without causing GvHD. Importantly, 41BBζ-sIL15 GPC3-CAR Vδ1 cells displayed enhanced tumor-specific proliferation that resulted in better tumor control without any toxicity. Conclusions: Our results show that expanded Vδ1 T cells engineered with GPC3-CAR and sIL-15 represent a promising platform for safe and effective off-the-shelf treatment of HCC.

Combining DNA Vaccine and AIDA-1 in Attenuated Salmonella Activates Tumor-Specific CD4+ and CD8+ T-cell Responses.

Stimulation of tumor-specific responses in both CD4+ and CD8+ T cells has been a challenge for effective tumor vaccines. We designed a vaccine vector containing the AIDA-1 autotransporter and DNA vaccine elements, generating a murine melanoma vaccine that was delivered by the attenuated Salmonella strain SL7207. Growth of murine subcutaneous melanoma was significantly inhibited by intranasal immunization with the Salmonella tumor vaccine. The vaccine activated tumor-specific CD4+ and CD8+ T-cell responses, with increased T-cell proliferation, tumor antigen-specific Th1 cytokine production, increased percentages of tetramer positive cells, and cytotoxicity. CD4+ or CD8+ T-cell depletion resulted in the loss of antitumor activity of the Salmonella tumor vaccine, suggesting that the efficacy of the vaccine was dependent on both CD4+ and CD8+ T cells. Lung metastasis of the tumor was also inhibited by vaccine treatment. Similarly, the percentages of tumor-specific Th1 cytokine production by CD4+ and CD8+ T cells in the spleen, tumor, and bronchoalveolar lavage were increased after vaccine treatment. Tumor-specific proliferation of CD4+ and CD8+ T cells was also promoted by the vaccine. Tetramer staining and cytotoxicity assay showed enhanced tumor-specific CD8+ T-cell response after vaccine treatment. Therefore, the Salmonella tumor vaccine could activate both tumor-specific CD4+ and CD8+ T-cell responses. This vaccine strategy may be widely applicable to the development of oral or nasal vaccines against tumors. Cancer Immunol Res; 5(6); 503-14. ©2017 AACR.

IL-17RC is critically required to maintain baseline A20 production to repress JNK isoform-dependent tumor-specific proliferation

The IL-17/IL-17R axis has controversial roles in cancer, which may be explained by tumor-specific results. Here, we describe a novel molecular mechanism underlying IL-17RC-controlled tumor-specific proliferation. Triggered by IL-17RC knockdown (KD), B16 melanoma and 4T1 carcinoma cells inversely altered homeostatic tumor proliferation and tumor growth in vitro and in vivo. In contrast to the existing dogma that IL-17RC-dependent signaling activates the JNK pathway, IL-17RC KD in both tumor cell lines caused aberrant expression and activation of different JNK isoforms along with markedly diminished levels of the ubiquitin-editing enzyme A20. We demonstrated that differential up-regulation of JNK1 and JNK2 in the two tumor cell lines was responsible for the reciprocal regulation of c-Jun activity and tumor-specific proliferation. Furthermore, we showed that A20 reconstitution of IL-17RCKD clones with expression of full-length A20, but not a truncation-mutant, reversed aberrant JNK1/JNK2 activities and tumor-specific proliferation. Collectively, our study reveals a critical role of IL-17RC in maintaining baseline A20 production and a novel role of the IL-17RC-A20 axis in controlling JNK isoform-dependent tumor-specific homeostatic proliferation.

Comprehensive Analysis of Surface Antigens on Adult T-Cell Leukemia/Lymphoma (ATL) Cells and Search for ATL-Initiating Cell Markers

Adult T-cell leukemia/lymphoma (ATL) is highly aggressive malignancy caused by human T-cell leukemia virus type 1 (HTLV1). Intensive combination chemotherapy can initially reduce ATL cells, but relapses are common. Today many kinds of tumors are considered to be organized in a hierarchy of heterogeneous cell populations, with only a small proportion of cancer initiating cells (CICs) capable of sustaining tumor formation and growth. Even if most of tumor cells are killed, remaining chemo-resistant CICs can be causes of relapses. However, CICs of ATL have not been identified yet. Our first goal is to identify ATL-initiating cells using in-vitro and in-vivo models.Because co-culture of HTLV1-infected ATL cells and normal lymphocytes results in extraordinarily high HTLV1 integration into normal lymphocytes, which is not seen in the bodies of patients, purification of ATL cells is necessary for evaluation of tumor-specific proliferation. We reported that HTLV1-infected ATL cells could be specifically enriched in the CD4+CADM1+ fraction, while the HTLV-1 basic leucine zipper (HBZ) gene was not detected in CD4+CADM1- cells by PCR analysis. To purify ATL cells, CD4+CADM1+ gating was used.First, we performed comprehensive analysis of surface antigens specifically on ATL cells. Peripheral blood mononuclear cells (PBMCs) were isolated from typical acute-type ATL patients and healthy volunteers. Using flow cytometry and gating, surface expression of 105 antigens, including activated T-cell markers, cell adhesive molecules, and lineage markers, was analyzed. The expression on ATL cells was compared with other CD4-positive non-ATL lymphocytes. Statistical hierarchical clustering analysis of 10 sample groups showed that ATL cells were all grouped into the same cluster, and markers specific for acute-type ATL cells were therefore picked up as candidate markers.Second, CD4+CADM1+ cells were classified by differences in expression of those candidate markers and sorted using 12-color flow cytometry. Although growing primary ATL cells in vitro is very difficult, it was reported that only a small proportion of ATL cells can survive and proliferate on the murine MS-5 stromal cell line, which also allows the proliferation of some ALL and hematopoietic progenitor cells. We repeated these 14-days in-vitro assays and tried to identify the cells capable of surviving and proliferating on MS-5, which we consider to be ATL-initiating cells. Although most of picked-up markers didn’t have any impacts on survival and proliferation of ATL cells, several surface antigens affected the results. After confirmation and prioritization, CD25+ and CD71- fractions were finally picked up. Combining these two fractions, we found that CD71-CD25+CD4+CADM1+ cells could survive and proliferate on MS-5, while other CD4+CADM1+ cells died off in many cases. Even in a case where CD71-CD25+ cells accounted only for 1.1% among the CD4+CADM1+ fraction, CD71-CD25+ cells exclusively survived and proliferated in vitro (figure 1). Moreover, CD71-CD25+ cells could generate CD71+ and CD25- cells on MS-5. In serial culture models, the CD71-CD25+ cells could serially generate other CD4+CADM1+ cells in vitro.Then, we focused on the clinical course of actual ATL patients, and followed up the CD71-CD25+ ATL cells before and after chemotherapy. After chemotherapy, the frequency of CD71-CD25+ cells among CD4+CADM1+ cells became obviously higher, and they therefore seemed to be resistant to chemotherapy. In a case where robust reduction of ATL cells was achieved, more than 90% of remaining ATL cells were in the CD71-CD25+ fraction.Lastly, we compared the in-vivo proliferation of CD71-CD25+ ATL cells and other CD4+CADM1+ cells. Both cells were transplanted intravenously into neonatal NOD/Shi-scid/IL-2Rγnull (NOG) mice within 48 hours from birth. CD71-CD25+CD4+CADM1+ cells could proliferate in vivo while others couldn’t as far as we tried. Moreover, flow cytometric analysis of murine peripheral blood in 70 days after transplantation showed that CD71-CD25+CD4+CADM1+ cells could generate ATL cells with other phenotype seen in primary ATL patients.In summary, we successfully found that CD71-CD25+CD4+CADM1+ cells could generate other ATL cells in vitro and in vivo. This research suggested ATL-initiating cells could be in the CD71-CD25+CD4+CADM1+ fraction. [Display omitted] DisclosuresTojo:Novartis: Research Funding, Speakers Bureau.

Th-17 Lymphocytes, Not Regulatory T Cells, Mediate Immune Regulation of Bone Marrow Infiltrating Lymphocytes and Induce Osteoclast Activation in Multiple Myeloma.

The bone marrow of myeloma patients is a reservoir of marrow infiltrating lymphocytes (MILs) that upon activation with anti-CD3 and anti-CD28 antibodies show significant tumor specificity against both mature myeloma plasma cells and their clonotypic precursors, whereas activated peripheral blood lymphocytes (PBLs) fail to demonstrate any tumor specificity. Here we examine the major differences between MILs and PBLs of both myeloma patients and normal donors. In myeloma, CD4+/CD25+ MILs lack a regulatory T-cell (Treg) phenotype as shown by the absence of FoxP3 expression and the inability to suppress tumor-specific proliferation of effector T cells. In contrast, the CD4+/CD25+ PBLs express FoxP3 and suppress tumor specific proliferation. Analysis of MILs and PBLs from normal individuals reveals the exact opposite (more Tregs in the marrow than blood). Considering the abundance of plasma cell-derived IL-6 in myeloma marrow, we hypothesize that IL-6 skewing of MILs towards the effector Th17 phenotype could explain the reciprocal paucity of Tregs in myeloma and relative abundance in normal bone marrows. Intracellular staining shows increased expression of IL-17 in myeloma CD4 MILs (2.7%) as compared to either myeloma PBLs (0.02%) or normal MILs (0.7%). The Th17 cytokine secretion pattern also appears more pronounced in myeloma-derived MILs as compared to either myeloma PBLs or normal MILs respectively (see table). Th17 T cells have recently been implicated in osteoclastogenesis of rheumatoid arthritis. In fact, bone marrow serum IL-17 levels correlate with the degree of lytic bone disease. In experiments utilizing M-CSF and RANK-L as the osteoclast differentiation medium, we show that the addition of IL-17 to the culture medium increases the number of mature osteoclasts by 2.3 fold whereas γIFN reduces mature osteoclast numbers by 80%. These findings explain the profound differences seen in MILs of normal and myeloma patients and implicate Th17 MILs in the generation of lytic bone disease. Activation of myeloma MILs with anti-CD3/CD28 skews the population from Th17 to a γIFN-producing Th1 phenotype. As such, targeting Th17 T cells or utilizing adoptive T cell therapy with activated, γIFN-producing MILs may represent a novel therapeutic mechanism to target osteoclastogenesis and reduce bone disease in myeloma.Th-17 Cytokine ProfileN=56MM MILsMM PBLsNL MILsIL-6 (pg/ml)303.76.5IL-23 (pg/ml)24619.635.9IL-17 (pg/ml)12.20.45.1

Detection of Immune Responses in Sentinel Nodes Draining Human Urinary Bladder Cancer

Being the first lymph node to receive drainage from the tumour area, the sentinel node offers a unique possibility to obtain tumour‐reactive lymphocytes. We investigated antitumour immune responses in sentinel nodes from patients with bladder cancer, by assaying tumour‐specific proliferation and TCR Vβ repertoires. During tumour surgery, sentinel lymph nodes were identified by peri‐tumoural injection of blue dye. Fresh specimens of tumour, sentinel and nonsentinel lymph nodes were obtained, and single‐cell suspensions were prepared. Cells were assayed for reactivity against autologous tumour extract in [3H]‐thymidine incorporation assays and characterized by flow cytometry. Parallel analyses of the expression of Vβ gene families were performed with padlock probes, linear oligonucleotides which upon target recognition can be converted to circular molecules by a ligase. Probes were reacted with cDNA prepared from magnetically separated CD4+ cells, and the TCR repertoire was determined by hybridizing the products to oligonucleotide microarrays. Dose‐dependent proliferation in response to tumour extract could be detected in sentinel lymph nodes. Common clonal expansions were detected among tumour‐infiltrating lymphocytes and in sentinel lymph nodes. Nonsentinel lymph nodes displayed a divergent TCR Vβ repertoire. These results indicate an ongoing immune response against tumour antigens in sentinel nodes, draining urinary bladder cancer. Identification of sentinel lymph nodes makes it possible to obtain tumour‐reactive lymphocytes for use in adoptive immunotherapy.

Autologous and MHC class I–negative allogeneic tumor cells secreting IL-12 together cure disseminated A20 lymphoma

Cytokine gene-modified tumor cells have increased immunogenicity and retain the antigenic repertoire of a particular neoplasia. However, practical concerns have led to an increased interest in allogeneic gene-transduced bystander cells as a broader source of cytokines for autologous tumor cell-based vaccines. Here, we show that allogeneic B78H1 major histocompatibility complex (MHC) class I-negative and -positive (H-2K(b)- and D(b)-transfected) cells induced cytotoxic T lymphocytes (CTLs) and protection in BALB/c mice at comparable levels in response to a challenge with C26 (H-2(d)) colon carcinoma cells sharing the tumor-associated antigen envelope glycoprotein 70 (env-gp70) with both cell lines. Class I-negative B78H1 cells transduced to express interleukin-12 (IL-12) and mixed with autologous A20 tumor cells led to eradication of preestablished A20 lymphoma in 50% or 100% of treated mice after 3 or 4 vaccinations, respectively, whereas A20 cells alone or mixed with nontransduced B78H1 cured none or 50% of mice after 3 or 4 vaccinations, respectively. Immunization with the IL-12-producing bystander cell line increased tumor-specific proliferation and type 1 cytokine production by CD4(+) T cells. By contrast, CD4 T-cell function appeared impaired after immunization with A20 cells alone or mixed with B78H1 cells. Indeed, only CD4(+) T cells from IL-12-treated mice could be restimulated with anti-OX40 monoclonal antibody (mAb) in place of a fourth cellular boost. Moreover, the IL-12-based tumor vaccine induced expansion of tumor-specific interferon-gamma (IFN-gamma)-producing CD8(+) T cells. These results are clinically relevant for the development of feasible IL-12 cancer vaccines based on engineered class I-negative bystander cells.

Tumor Cell Lysate-Pulsed Dendritic Cells Are More Effective Than TCR Id Protein Vaccines for Active Immunotherapy of T Cell Lymphoma

TCR Id protein conjugated to keyhole limpet hemocyanin (KLH) (TCR Id:KLH) and injected with a chemical adjuvant (QS-21) induces a protective, Id-specific immune response against the murine T cell lymphoma, C6VL. However, Id-based immunotherapy of C6VL has not demonstrated therapeutic efficacy in tumor-bearing mice. We report here that C6VL lysate-pulsed dendritic cells (C6VL-DC) vaccines display enhanced efficacy in both the prevention and the therapy of T cell lymphoma compared with TCR Id:KLH with QS-21 vaccines. C6VL-DC vaccines stimulated potent tumor-specific immunity that protected mice against lethal challenge with C6VL and significantly enhanced the survival of tumor-bearing mice. Tumor-specific proliferation and secretion of IFN-gamma indicative of a Th1-type immune response were observed upon ex vivo stimulation of vaccine-primed lymph node cells. Adoptive transfer of immune T cell-enriched lymphocytes was sufficient to protect naive recipients from lethal tumor challenge. Furthermore, CD8(+) T cells were absolutely required for tumor protection. Although C6VL-DC and control vaccines stimulated low levels of tumor-specific Ab production in mice, Ab levels did not correlate with the protective ability of the vaccine. Thus, tumor cell lysate-pulsed DC vaccines appear to be an effective approach to generate potent T cell-mediated immune responses against T cell malignancies without requiring identification of tumor-specific Ags or patient-specific Id protein expression.

Irradiated tumor cell vaccine for treatment of an established glioma. II. Expansion of myeloid suppressor cells that promote tumor progression.

These studies report the identification of a population of myeloid suppressor cells (MSC) that are preferentially enriched in the spleens and tumor-infiltrating mononuclear cells (TIMC) from T9.F-vaccinated animals. In this model designed to mimic immunotherapy for an established intracranial (i.c.) glioma, animals were given an i.c. inoculum with 5 x 10(4) T9 glioma cells at day 0, followed by a subcutaneous (s.c.) injection of 5 x 10(6) irradiated T9.F glioma cells 5 days later. Unexpectedly, we found that the survival of these T9.F-vaccinated animals was dramatically shorter than their age-matched counterparts who received only saline injections. Since MSC have previously been demonstrated to be associated with tumor progression, the question arose of whether MSC might play a role in the rapid tumor progression observed in this model. Analysis of the spleen cells and TIMC revealed an increase in the population of myeloid cells expressing granulocytic and monocytic markers. Both the polyclonal and tumor-specific proliferation of splenic T cells and tumor-infiltrating T lymphocytes (T-TIL) from T9.F-vaccinated animals were significantly inhibited in the presence of these myeloid cells. Furthermore, the adoptive transfer of MSC into animals bearing a 5-day T9 glioma caused rapid tumor progression. Reduced survival of the glioma-bearing vaccinated rats was associated with enhanced tumor growth, as well as with an increased density of T-TIL. However, purified T-TIL did not show any discernable signs of inherent defects in terms of their effector functions and T cell receptor (TCR) signal transduction protein levels. Therefore, we believe that an MSC population is responsible for inhibiting the anti-tumor T cell response, resulting in the enhanced growth of the i.c. glioma, and may represent a significant obstacle to immune-based therapies.

Role of IL‐2, IL‐4 and IL‐6 in the growth and differentiation of tumor‐specific CD4+ T helper and CD8+ T cytotoxic cells

We have earlier observed that 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU), a chemotherapeutic drug, cured 90-100% of mice bearing a syngeneic Ia- T-cell lymphoma (LSA) and furthermore, 100% of the BCNU-cured mice could reject homologous tumor rechallenge. In the present study, purified CD4+ and CD8+ T cells isolated from BCNU-cured mice were used to investigate the mechanism by which such T cells recognized and responded to the tumor-specific antigens. The responsiveness of CD4+ T cells to LSA was dependent on processing and presentation of tumor-specific antigens by syngenic Ia+ splenic antigen-presenting cells (APC). Such activated CD4+ T cells endogenously produced IL-2 but not IL-4 and only IL-2 acted as an autocrine growth factor inasmuch as anti-IL-2 receptor antibodies but not anti-IL-4 antibodies inhibited the CD4+ T cell proliferation. In contrast, the CD8+ T cells failed to produce endogenous growth factors when stimulated with LSA alone or with LSA plus APC, and therefore failed to proliferate. However, in the presence of exogenous recombinant IL-2 (rIL-2), CD8+ T cells could proliferate directly in response to LSA-stimulation, even in the absence of APC. Addition of exogenous rIL-4 alone to cultures induced CD4+ but not CD8+ T cells to proliferate. However, rIL-4 in the presence of rIL-2, could synergize and induce tumor-specific proliferation of CD8+ cells. These data suggested that for IL-4 to act as a T-cell growth factor, the presence of IL-2 was essential, either in the form of endogenously secreted IL-2 (CD4+ T cells) or exogenous IL-2 (for CD8+ T cells). In contrast to rIL-2 and rIL-4, rIL-6 failed to induce growth when used alone or in combination with rIL-2 or rIL-4. Furthermore, when tested individually, only rIL-2 but not rIL-4 or rIL-6 could support the cytotoxic differentiation of CD8+ T cells. The present study suggests that the early events in responsiveness to LSA tumor may involve activation of the IL-2-producing Th1 subpopulation of CD4+ helper cells which in turn activate IL-2 dependent CD8+ cytotoxic T cells. IL-4 if produced subsequently, may act synergistically with IL-2 to promote the growth of CD4+ and CD8+ T cells.

Tumour-associated proliferative responses in vitro of regional lymph nodes draining solid cancers in man.

The proliferative responses in vitro of tumour-draining lymph node lymphocytes were evaluated against autologous colon and lung carcinoma cells. The reactivity of lymphocytes appeared to be directed against tumour-associated rather than tumour-specific antigens. The lymphocyte reactivity detected was not due to an autologous mixed lymphocyte reaction. Recombinant interleukin-2 augmented the responses detected but not their tumour specificity. Phenotypic characterisation indicated the presence of T suppressor/cytotoxic (TS/C) cells as well as natural killer (NK) cells. Only the later, however, were active in functional cytotoxicity assays. The inability to generate both tumour-specific proliferation of tumour-draining lymph node lymphocytes and tumour-specific cytotoxic killer cells may be due to the presence of suppressor cells in the regional lymph nodes; preliminary data suggest the presence of such cells.

Helper and suppressor functions of panned populations of immune peritoneal T cells with reactivity to the rat mammary adenocarcinoma 13762A

The phenotype of glass-adherence-depleted tumor-immune peritoneal exudate lymphocytes (PEL) which generated anti-tumor reactivity against the rat mammary adenocarcinoma 13762A in vitro was examined by indirect panning. Monoclonal antibodies W3/25 and OX8, directed against the CD4 and CD8 differentiation antigens, respectively, were used to separate immune PEL into subsets of functionally different T cells. The panned populations of immune PEL were examined for anti-tumor reactivity in three different in vitro assays. Tumor-specific proliferation, tumor-specific induction of the helper lymphokine interleukin 2 (IL-2), and tumor-specific induction of an antiproliferative tumor-induced suppressor lymphokine (TISL) were determined. Panning experiments together with indirect immunofluorescence analysis of unpanned immune PEL indirectly indicated that a proportion of cells (15–20%) coexpressed CD4 and CD8 antigens. Strong tumor-specific proliferation and IL-2 and TISL production were generated from these double-positive cells, as determined by double-panning experiments. Significant tumor-specific proliferation and IL-2 production were produced also from CD4 +CD8 − cells, but TISL production was minimal, and could be accounted for by contaminating CD4 +CD8 + cells. CD4 −CD8 + cells produced negligible responses against the tumors as measured by these three assays, and no synergistic responses were demonstrated when CD4 −CD8 + cells were incubated together with CD4 +CD8 − cells. These data demonstrated that CD4 +CD8 + T cells exist in primed populations of rat peripheral lymphocytes, and that both helper and suppressor functions were generated from these double-positive cells.