CD95/Fas-triggered apoptosis of activated T lymphocytes is prevented by dendritic cells through a CD58-dependent mechanism

Bridging live-cell imaging and next-generation cancer treatment

By providing spatial, molecular and morphological data over time, live-cell imaging can provide a deeper understanding of the cellular and signalling events that determine cancer response to treatment. Understanding this dynamic response has the potential to enhance clinical outcome by identifying biomarkers or actionable targets to improve therapeutic efficacy. Here, we review recent applications of live-cell imaging for uncovering both tumour heterogeneity in treatment response and the mode of action of cancer-targeting drugs. Given the increasing uses of T cell therapies, we discuss the unique opportunity of time-lapse imaging for capturing the interactivity and motility of immunotherapies. Although traditionally limited in the number of molecular features captured, novel developments in multidimensional imaging and multi-omics data integration offer strategies to connect single-cell dynamics to molecular phenotypes. We review the effect of these recent technological advances on our understanding of the cellular dynamics of tumour targeting and discuss their implication for next-generation precision medicine.

Multidimensional single-cell analysis identifies a role for CD2-CD58 interactions in clinical antitumor T cell responses

The in vivo persistence of adoptively transferred T cells is predictive of antitumor response. Identifying functional properties of infused T cells that lead to in vivo persistence and tumor eradication has remained elusive. We profiled CD19-specific chimeric antigen receptor (CAR) T cells as the infusion products used to treat large B cell lymphomas using high-throughput single-cell technologies based on time-lapse imaging microscopy in nanowell grids (TIMING), which integrates killing, cytokine secretion, and transcriptional profiling. Our results show that the directional migration of CD19-specific CAR T cells is correlated with multifunctionality. We showed that CD2 on T cells is associated with directional migration and that the interaction between CD2 on T cells and CD58 on lymphoma cells accelerates killing and serial killing. Consistent with this, we observed that elevated CD58 expression on pretreatment tumor samples in patients with relapsed or refractory large B cell lymphomas treated with CD19-specific CAR T cell therapy was associated with complete clinical response and survival. These results highlight the importance of studying dynamic T cell–tumor cell interactions in identifying optimal antitumor responses.

CD58 Immunobiology at a Glance

The glycoprotein CD58, also known as lymphocyte-function antigen 3 (LFA-3), is a costimulatory receptor distributed on a broad range of human tissue cells. Its natural ligand CD2 is primarily expressed on the surface of T/NK cells. The CD2-CD58 interaction is an important component of the immunological synapse (IS) that induces activation and proliferation of T/NK cells and triggers a series of intracellular signaling in T/NK cells and target cells, respectively, in addition to promoting cell adhesion and recognition. Furthermore, a soluble form of CD58 (sCD58) is also present in cellular supernatant in vitro and in local tissues in vivo. The sCD58 is involved in T/NK cell-mediated immune responses as an immunosuppressive factor by affecting CD2-CD58 interaction. Altered accumulation of sCD58 may lead to immunosuppression of T/NK cells in the tumor microenvironment, allowing sCD58 as a novel immunotherapeutic target. Recently, the crucial roles of costimulatory molecule CD58 in immunomodulation seem to be reattracting the interests of investigators. In particular, the CD2-CD58 interaction is involved in the regulation of antiviral responses, inflammatory responses in autoimmune diseases, immune rejection of transplantation, and immune evasion of tumor cells. In this review, we provide a comprehensive summary of CD58 immunobiology.

Gene expression differences in normal esophageal mucosa associated with regression and progression of mild and moderate squamous dysplasia in a high-risk Chinese population

A randomized, double-blinded, placebo-controlled 2 x 2 factorial chemoprevention trial was conducted in Linxian, China to assess the effects of selenomethionine and celecoxib on the natural history of esophageal squamous dysplasia. Results from this study indicated that asymptomatic adults with mild dysplasia were more likely to show an improvement when treated with selenomethionine compared with placebo (P = 0.02). Prompted by this finding, we examined the molecular profiles associated with regression and progression of dysplastic lesions in normal mucosa from 29 individuals, a subset of the Linxian cohort, using the Affymetrix U133A chip. Twenty differentially expressed genes were associated with regression and 129 were associated with progression when we compared the change in gene expression over time. Genes associated with immune response (n = 15), cell cycle (n = 15), metabolism (n = 15), calcium transport or calcium ion activity (n = 10), regulation of transcription (n = 9), signal transduction (n = 7), cytoskeleton and microtubules (n = 5), nucleotide processing and biosynthesis (n = 4), G-coupled signaling (n = 4), and apoptosis (n = 3) were present in the list of 149 genes. Using the Expression Analysis Systematic Explorer pathway analysis program, only the immune response pathway was significantly overrepresented among these 149 genes. Individuals whose lesions regressed seemed to have higher expression of genes associated with immune stimulation, such as antigen presentation, survival of T cells, and T-cell activation (HLA-DRA, HLA-DPA1, HLA-DBQ1, CD58, and FCER1A). In contrast, individuals whose lesions progressed had higher expression of genes involved in immune suppression and inflammation (CNR2, NFATC4, NFRKB, MBP, INHBB, CMKLR1, CRP, ORMS, SERPINA7, and SERPINA1). These data suggest that local and systemic immune responses may influence the natural history of esophageal squamous dysplasia.

Costimulation by CD137/4-1BB inhibits T cell apoptosis and induces Bcl-xLand c-FLIPshortvia phosphatidylinositol 3-kinase and AKT/protein kinase B

Costimulation is essential for induction of T lymphocyte proliferation and inhibition of activation-induced cell death. While signaling pathways activated following the ligation of the costimulatory molecule CD28 are well defined, less is known about the molecular events induced by alternative costimulators. CD137/4-1BB, a costimulatory member of the tumor necrosis factor receptor family, plays an important role during late primary T cell stimulation. Here, we demonstrate for the first time that inhibition of activation-induced cell death by exposure to the CD137/4-1BB ligand involves up-regulation of the anti-apoptotic protein c-FLIP(short). Inhibition of T cell death by 4-1BB ligation and up-regulation of c-FLIP(short) and Bcl-x(L) were abolished by blocking the phosphatidylinositol 3-kinase or the AKT/protein kinase B, which also mediate CD28-induced inhibition of activation-induced cell death. Our findings, therefore, demonstrate that costimulatory molecules, although belonging to different protein families and participating in distinct upstream signaling pathways, employ common downstream signaling pathways.

Necrotic death but not irradiation abolishes costimulation of T-cell effector functions and survival by CD80-expressing tumor cells

Tumor vaccination by the use of gene-modified cancer cells that provide costimulatory signals has been successfully applied in preclinical animal models and is currently evaluated in a variety of clinical settings. In previous work, we demonstrated the efficacy of B7.1/CD80 to promote tumor immunity in syngeneic murine models and to prevent deletion of activated T cells by activation-induced cell death (AICD). In clinical trials, tumor cell vaccines are generally inactivated to avoid transfer of live tumor cells, i.e., additional tumor burden. Previous data indicated, however, that inactivation of tumor cells by lethal ionizing irradiation abrogates tumor vaccination by CD80-expressing cells. Here, we compare living and irradiated allogeneic tumor cells regarding their capacity to induce T-cell effector functions and their propensity to interfere with T-cell deletion by apoptosis. Both lethally irradiated and nonirradiated tumor cells facilitated T-cell proliferation, tumor cell lysis, and interfered with T-cell AICD to a similar extent. In contrast, necrotic tumor cells failed to costimulate T-cell effector functions. Thus, irradiation does not seem to hamper tumor cell-mediated costimulation of T-cell effector functions. In contrast, necrosis of gene-modified tumor cells abrogates costimulation of T cells by CD80-expressing cells.

What price support? Ventricular assist device induced systemic response

Use of ventricular support systems has been associated with myriad systemic complications. Engendered by the blood-biomaterial interface of a unique host/device relationship, these complications include diverse humoral dyscrasias that frequently culminate in episodes of bleeding, hemolysis and thrombogenicity, heightened susceptibility to inflammation and infection, and transient immunal compromise. Recent endeavor in biocompatibility research has served to illustrate the critical role played by cellular, humoral, and neurohormonal components in regulating cytokine expression and has provided insight into the complexities involved in such biomechanical juxtapositions. The following is intended as a review of current literature attempting to address the many aspects of this host/device interaction and their consequences for the supported patient.

Inhibition of maturation and function of dendritic cells by intravenous immunoglobulin

Normal immunoglobulin G for therapeutic use (intravenous immunoglobulin [IVIg]) is used in an increasing number of immune-mediated conditions, including acute and chronic/relapsing autoimmune diseases, transplantation, and systemic inflammatory disorders. Several mutually nonexclusive mechanisms of action account for the immunoregulatory effects of IVIg. Although IVIg inhibits T-cell proliferation and T-cell cytokine production, it is unclear whether these effects are directly dependent on the effects of IVIg on T cells or they are dependent through the inhibition of antigen-presenting cell activity. Here, we examined the effects of IVIg on differentiation, maturation, and function of dendritic cells (DCs). We show that IVIg inhibits the differentiation and maturation of DCs in vitro and abrogates the capacity of mature DC to secrete interleukin-12 (IL-12) on activation while enhancing IL-10 production. IVIg-induced down-regulation of costimulatory molecules associated with modulation of cytokine secretion resulted in the inhibition of autoreactive and alloreactive T-cell activation and proliferation. Modulation of DC maturation and function by IVIg is of potential relevance to its immunomodulatory effects in controlling specific immune responses in autoimmune diseases, transplantation, and other immune-mediated conditions.

Cognate interactions between memory T cells and tumor antigen-presenting dendritic cells from bone marrow of breast cancer patients: bidirectional cell stimulation, survival and antitumor activity in vivo

Dendritic cells (DC) and T cells were generated from Ficoll separated bone marrow (BM) mononuclear cells of primary operated breast cancer patients according to new cell culture protocols. BM-DC were capable of functioning as professional antigen-presenting cells (APCs) and of inducing autologous antigen-specific memory T-cell responses to either tetanus toxoid recall antigen or to breast cancer antigens. Treatment with lipopolysaccharide (LPS) resulted in phenotypic and functional maturation of BM-DC. When BM-DC, pulsed with breast cancer-associated tumor antigens, were cocultured with autologous patient-derived BM-T cells to allow for cognate breast cancer antigen recognition and stimulation, apoptosis of T cells-which occurred in noncognate coculture systems-was inhibited. Furthermore, in cocultures allowing for antigen-specific cognate interactions, the expression on BM-DC of CD83, MHC class II, CD40 and CD86 molecules was upregulated and the cytokines IL-12 and IFN-alpha were produced in significantly elevated amounts. Adoptive transfer of breast cancer-reactive memory T cells together with APCs into human breast cancer-bearing NOD/SCID mice caused a regression of the tumor and prolonged survival of the animals. This was not the case when such animals had been treated by transfer of reactivated BM T cells without BM-DCs. Our findings suggest that cognate interactions between cancer patient-derived memory BM-T cells and tumor antigen-presenting BM-DCs are important for reciprocal cell stimulation, survival and therapeutic activity.

Adenoviral transduction of tumor cells induces apoptosis in co-cultured T lymphocytes

Adenoviral gene transfer of immunmodulatory molecules has been employed successfully in tumor vaccination studies to induce rejection of transplanted syngeneic tumors. In contrast, the response observed when treating chemically induced murine tumors is rather limited. The same applies for human malignancies. A number of reasons including poor transduction efficiency or insufficient T cell infiltration have been held accountable for this lack of efficacy. However, little attention has been given to effects of the adenoviral transduction itself on the T cell system. Here, we show that T cells are sensitized for activation-induced cell death after co-culture with adenovirally infected tumor cells. The levels of CD95/Fas ligand or TNF-alpha, both known mediators of activation induced cell death, however were not affected by the presence of adenovirus-infected target cells. Furthermore, supernatant transfer from adenovirally transduced or non-infected tumor cell cultures did not result in increased T cell apoptosis. This suggests that cell contact rather than a soluble factor is responsible for the induction of T cell apoptosis upon co-culture with adenovirally transduced tumor cells. Interestingly, and in line with our previous observations, activation-induced cell death was partially inhibited if T cells were co-cultured with tumor cells adenovirally transduced to express IL-7 and CD80, both molecules having the capacity to prevent T cell apoptosis.

The kiss of death: promises and failures of death receptors and ligands in cancer therapy

Death receptors and their ligands exert important regulatory functions in the maintenance of tissue homeostasis and the physiological regulation of programmed cell death. Currently, six different death receptors are known including tumor necrosis factor (TNF) receptor-1, CD95 (Fas/APO-1), TNF receptor-related apoptosis-mediating protein (TRAMP), TNF-related apoptosis-inducing ligand (TRAIL) receptor-1 and -2, and death receptor-6 (DR6). The signaling pathways by which these receptors induce apoptosis are similar and rely on oligomerization of the receptor by death ligand binding, recruitment of an adapter protein through homophilic interaction of cytoplasmic domains, and subsequent activation of an inducer caspase which initiates execution of the cell death programme. The ability of these receptors and their ligands to kill malignant cells was discovered early and helped to coin the term 'tumor necrosis factor' for the first identified death ligand. This review summarizes the current and rapidly expanding knowledge about the signaling pathways triggered by death receptor/ligand systems, their potency in experimental cancer therapy, and their therapeutic limitations, especially regarding their toxicity for non-malignant cells.

Apoptosis of antigen-specific T cells induced by oral administration of antigen: comparison of intestinal and non-intestinal immune organs

Oral administration of a protein without adjuvant brings about oral tolerance (systemic hyporesponsiveness) to that protein by mechanisms such as antigen-induced apoptosis. We monitored the number and apoptosis induction of CD4+ T cells in antigen-specific T cell receptor transgenic mice fed the antigen ovalbumin to identify where events leading to oral tolerance occurred. The antigen was distributed throughout the body, causing apoptosis and a decrease in cell number of CD4+ T cells in most of the lymphoid system: the spleen, peripheral lymph nodes, and the thymus which was not previously reported to be affected. Although apoptosis was induced in the Peyer's patches, the cell number did not change. Unexpectedly, T cells in the mesenteric lymph nodes did not undergo apoptosis; instead, they were more numerous as compared to that in the case of control animals not administered the antigen. The results suggested that the orally administered antigen activated the intestinal immune system, while it induced immune tolerance in other sites.