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The in vivo role of leukocyte function-associated antigen-1 in cytotoxic cell activity against tumors induced by Moloney-murine sarcoma/leukemia retroviral complex.
The in vivo role of LFA-1 molecule in the immune reaction to a murine retrovirus-induced tumor was investigated. Local and systemic treatment with high doses of anti-LFA-1 monoclonal antibody led to tumor progression by blocking CTL interaction with tumor cells without interfering with CTL generation and localization in the tumor mass.
[Immunotherapy of tumors of the central nervous system].
Malignant brain tumors are rapidly fatal and adjunction of chemo- and radio-therapy to surgical treatment has little changed their poor prognosis. The development of basic and clinical research in immunology of brain tumors has lead to new therapeutic strategies: 1) Humoral factors: Monoclonal antibodies (MAbs): alone or conjugated (to toxins, radionucleides or chemotherapeutic agents), MAbs can theoretically recognize antigens expressed by tumor cells and reach this target with high specificity. Large amounts of tumoricidal agents could be given to the tumor with low toxic effects to normal tissues. 2) Cellular factors: LAK cells: (lymphokine-activated-killer-cells) and activated TILs (tumor-infiltrating-lymphocytes) are autologous cytotoxic cells which can be produced by ex-vivo culture techniques and infused to the patient. These are very potent tumor-killer cells in vitro, however their in vivo effect is far less dramatic at the moment. 3) Cytokines: interferons, interleukins and other biological modifiers can act either directly on the tumor cells (cytotoxic effect) or indirectly through the modulation of the host-to-tumor response. 4) Combination of humoral and cellular factors: bispecific monoclonal antibodies are hybrid-molecules built from two different MAbs which can recognize two different targets, usually a tumor antigen on one hand and the T-cell-receptor (T 3) on the other hand. This combination of humoral and cellular effectors can theoretically lead to a preferential binding of effector cells to the tumor. All these new techniques are extensively studied in research laboratories and clinical trials without clear therapeutical benefit for the moment.
Genetic modification of a murine fibrosarcoma to produce interleukin 7 stimulates host cell infiltration and tumor immunity.
Retroviral-mediated gene transfer was used to introduce and express the gene for murine interleukin 7 (IL-7) in a fibrosarcoma tumor (FSA). The tumorigenicity of these genetically modified FSA cells was greatly decreased in immunologically intact syngeneic mice but was unaltered in T-cell-deprived mice. IL-7-infected tumors that did grow in intact animals from large size inocula did so slowly and had a high incidence of spontaneous regression. Furthermore, mice that had rejected tumors became specifically immune to challenge with uninfected parental tumor cells. IL-7-infected FSA growing in intact mice were heavily infiltrated with host T-cells that were presumably responsible for slow growth and tumor regression, and tumor cells were in the minority. Fluorescence-activated cell sorter analysis showed that there was a 530% increase in T-cells in IL-7-infected FSA compared with control tumors. CD8+ T-cells were particularly elevated, but CD4+ lymphocytes were also increased in number, as were eosinophils and basophils. The CD4+:CD8+ ratio in IL-7-infected FSA was 1:1.7 in comparison to 1:0.6 in control tumors. Lymphocytes isolated from IL-7-producing tumors had greatly enhanced cytotoxicity towards uninfected, parental FSA cells. Killing of non-cross-reacting fibrosarcoma line was also increased but to a much lesser extent. Injection of recombinant human IL-7 directly into established FSA tumors slowed their growth and, in a significant number of instances, caused complete regression. Mice that had rejected tumor became specifically immune. The dose that was needed for this effect was, however, somewhat large: 20 micrograms twice daily for 10 days. This result contrasts with the efficacy of IL-7 gene infection in stimulating responses to the same tumor. These considerations make IL-7 a good candidate for tumor-directed cytokine gene therapy.
Prospects for human gene therapy.
Retroviral vectors containing marker genes and the sequence for human proteins have been used to transduce cultured lymphocytes, which have then been reinfused into patients. Circulating hematopoietic progenitor cells from human fetal cord blood obtained at the time of term and premature deliveries as early as 19 weeks of gestation have been shown to express such transduced genes in vitro. Cord blood cells from fetal sheep sampled and transduced ex vivo and transfused back in utero expressed marker genes up to two years after birth. Although the efficiency of gene transfer into cells and their long-term expression need to be improved, the potential exists for treating some genetic diseases after prenatal diagnosis either in utero or shortly after birth.
Postoperative adjuvant immunochemotherapy and infiltration of dendritic cells for patients with advanced gastric cancer.
To determine the group of patients for whom a biological response modifier is useful, the efficacy of postoperative adjuvant immunotherapy was investigated with regard to infiltration of dendritic cells (DC) in patients with advanced gastric cancer who underwent absolute curative resection. The infiltration of DC was classified into marked and slight. The chemotherapy group was prescribed mitomycin C and tegafur, while for the immunochemotherapy group a biological response modifier, PSK, was also prescribed in survival between the chemotherapy and immunochemotherapy groups. In patients with slight infiltration, however, the 5 - year survival rates were 0% in the chemotherapy and 15% in the immunochemotherapy group. Patients given PSK survived longer than those given chemotherapy only (P less than 0.05). Therefore, adjuvant immunotherapy may be considered for patients with advanced gastric cancer with slight infiltration of DC.
Large scale expansion of human tumor infiltrating lymphocytes with surface-modified stimulator cells for adoptive immunotherapy.
Expansion of tumor infiltrating lymphocytes (TIL) in vitro is hampered by several factors, including a limited amount of lymphocytes obtained from different tumors, unknown target antigens and limited supply of antigen-presenting cells (APC) which are generally believed to be essential in the classical way of T cell stimulation and expansion. In approaching these difficulties, we have recently used surface-oxidized allogeneic PBL to stimulate the TIL periodically in the presence of a low dose of rIL-2 (200 IU/ml). TIL derived from 22 (out of 23) tumor specimens could be expanded with 20 -10(7) fold increases over 6-16 weeks to a sufficient amount of 10(9) -10(11) cells for adoptive immunotherapy. In contrast, only 2-100 fold increase were observed in six tumor specimens (out of 23) when 200 IU/ml rIL-2 was used only. The phenotypes, autologous tumor reactivity and cytolytic capability of TIL propagated with surface-oxidized stimulators were similar to those expanded in the presence of IL-2 alone. These data suggest that expanding TIL with surface-modified stimulator cells could be a useful alternative method to obtain a large amount of tumor specific cytolytic T cells for clinical immunotherapeutic use, irrespective of tumor-antigen stimulation and MHC restriction.
Immunology of the bladder.
Immunobiology techniques that once were the domain of research are increasingly being applied in the clinic. Transitional epithelium of the bladder undergoes some recognized immunologic changes as it becomes malignant, and their detection may have prognostic value. Examples of such changes are deletion of the ABO(H) blood group antigens, inappropriate expression of Lewis antigens, loss of beta-2 microglobulin and the MHC class 1 heavy chain, and alterations in the production of cellular adhesion molecules and integrins. Other possibly useful markers are ras oncogene products, Thomsen-Friedenreich antigen, epidermal growth factor receptor, and perhaps antigens unique to transitional-cell carcinoma.
Immunology of hepatocellular carcinoma.
The immune surveillance theory continues to remain a powerful force in cancer research and therapy despite the varying degrees of enthusiasm from both its supporters and critics. The role of both specific and non-specific immune responses in the host's defense against hepatocellular carcinoma is presented as well as the possibilities of immune-system manipulation for the prevention and therapy of this tumour.
Topical BCG for recurrent superficial bladder cancer.
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Prospects for gene therapy of human disease.
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Engraftment of human peripheral blood leukocytes into severe combined immunodeficient mice results in the long term and dynamic production of human xenoreactive antibodies.
Severe combined immunodeficient (SCID) mice engrafted with human peripheral blood leukocytes (hu-PBL-SCID) represent a potentially important small animal model for the study of human immune function. Attempts to generate human primary immune responses to exogenous Ag in the hu-PBL-SCID have had limited success which raises questions about the functional capacity of human lymphocytes in the SCID environment. Here, we demonstrate that the spontaneously secreted human Ig in hu-PBL-SCID includes antibodies with specificity for several different mouse RBC (mRBC) proteins. These antibodies apparently reflect the transfer of peripheral B cells which are responsible for the production of naturally occurring xenoreactive antibodies in the donor. Western blot analysis showed that engraftment of anti-mRBC specificities was random among mice receiving PBL from the same donor sample. In at least one mouse, this engraftment was polyclonal and included human IgM and IgG which recognized at least 12 different mRBC proteins ranging in size from 35 to > 200 kDa. Anti-mRBC specificities were found to vary with time demonstrating a dynamic expression of the human xenoreactive repertoire in hu-PBL-SCID. In contrast to mice engrafted with human PBL, mice engrafted with another source of human B cells, i.e., tumor-infiltrating leukocytes, produced very little or no human anti-mRBC antibody. Ag-driven proliferation of xenoreactive clones may result in a skewing of the engrafted human B cells in hu-PBL-SCID which could account in part for the limited ability of hu-PBL-SCID to respond to exogenous Ag. The long term production of anti-mRBC antibodies and the modulation of the expressed xenoreactive repertoire observed in hu-PBL-SCID represents an opportunity to study the molecular genetics and cell biology of the human humoral immune response to a defined complex Ag.
Special subtypes of pulmonary adenocarcinomas indicated by different tumor cell HLA-expression and stromal infiltrates. A light, electron microscopic and immunohistologic study.
A total of 31 human peripheral adenocarcinomas (AC) of the lung were subclassified by light and electron microscopy according to their phenotypic characteristics. The expression of HLA-A,B,C and HLA-DR on tumor cells, and the degree of subclassified mononuclear cell infiltration were determined using immunohistologic and morphometric methods. The study shows that pulmonary AC can be subdivided in two main types with different properties. The first type is characterized by mucin production comparable to that of bronchial goblet cells. These mucinous AC of type I show nearly no expression of HLA-DR; the tumor volume fraction with HLA-A,B,C expression is greatest in highly differentiated AC I, and decreases significantly with lower grades of differentiation. The AC of type II, possibly originating from the bronchioloalveolar transitional zone, show properties of Clara cells and of type II-pneumocytes by light and electron microscopy. These features include apically located electron-dense granules and lamellar bodies occurring often simultaneously. Both groups of HLA-antigens, HLA-A,B,C and HLA-DR, are homogeneously distributed in a similar phenotypic fashion to Clara cells and pneumocytes II of the normal lung. The significant differences in mononuclear cell infiltration between the two tumor types are possibly induced by the different HLA-DR expression, which have not been seen in AC from other sites. In AC II with homogeneous HLA-DR expression in the tumor epithelium, the numbers of tumor-infiltrating Langerhans cells, and T- and B-lymphocytes are significantly higher than in AC I, possibly indicating better host immunologic defense mechanisms against these tumors.
Functional activity of human tumor-infiltrating macrophages.
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MIF-CD74 axis facilitates MDSC infiltration in the tumor microenvironment of pancreatic ductal adenocarcinoma.
Immune checkpoint inhibitors show insufficient efficacy against pancreatic ductal adenocarcinoma (PDAC). The tumor microenvironment (TME) has a remarkable influence on responsiveness to cancer immunotherapy. The aim of this study was to investigate immunosuppressive characteristics of TME in PDAC tissues. The flow cytometry (FCM) of PDAC surgical specimens revealed that the profile of tumor-infiltrating leukocytes was classified into myeloid cell- and T-cell-dominant subtypes; the myeloid subtype was associated with poorer patient outcomes. Myeloid-derived suppressor cells (MDSCs) showed the highest hazard ratio among various myeloid cell types. Single-cell RNA sequencing and FCM revealed that most MDSCs, but not lymphocytes, in PDAC tissues characteristically express CD74. Macrophage migration inhibitory factor (MIF), a CD74 ligand, was highly expressed in cancer-associated fibroblasts (CAFs) and cancer cells. Spatial transcriptomics demonstrated that the MIF-CD74+ myeloid cell interaction was recognized in CAF-dominant areas in PDAC tissue. CAFs expressing immune suppressor molecules such as MFAP5 and LRRC15 were consistent with MIF+ CAFs. Furthermore, MIF+ CAFs enhanced the migratory activity of MDSCs and promoted MDSC induction and activation. In the murine model, MDSCs were significantly increased in MIF-expressing PDAC tumors, as were CD74+ M-MDSCs per M-MDSC, confirming in vivo interaction between CD74 and MIF. MDSCs play a crucial role in creating an immunosuppressive TME in PDAC; the MIF-CD74 axis drives interactions between MDSCs and CAFs.
In vivo genome-wide CRISPR screens identify FOXR1 as a suppressor of CD8+ T cell antitumor immunity.
T cell dysfunction critically limits the efficacy of T cell-based immunotherapies in solid tumors, yet the intrinsic regulators of T cell dysfunction remain incompletely understood. Through an in vivo genome-wide CRISPR screen in tumor-infiltrating CD8+ T cells, we identified Forkhead Box R1 (FOXR1) as a potent transcriptional suppressor of CD8+ T cell effector functions. Genetic ablation of FOXR1 significantly enhanced cytokine production and cytotoxic capacity in both murine and human CD8+ T cells, whereas its overexpression impaired T cell activation and effector molecule expression. Mechanistically, multiomics integration of RNA-seq, CUT&Tag-seq, and ATAC-seq revealed that FOXR1 binds directly to promoter regions of key effector genes, including IL2, GZMB, and PRF1, and represses their expression. Importantly, FOXR1 deletion in human anti-CD19 CAR T cells improved their efficacy against solid tumors, demonstrating that FOXR1 is a checkpoint of T cell effector function and targeting FOXR1 is a promising strategy to enhance CAR T cell efficacy against solid tumors.
A Phase II Feasibility Study Combining Pembrolizumab and Metformin in Patients with Metastatic Head and Neck Cancer.
PURPOSE: Survival for recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC) remains low with <20% immunotherapy response. Metformin increases tumor-infiltrating CD8+ T and natural killer (NK) cells, which harbor PD-1. In this phase II clinical trial (NCT04414540), we combined metformin and pembrolizumab to evaluate the overall response rate (ORR) in R/M HNSCC and assess NK-cell activity. PATIENTS AND METHODS: Eligible patients were randomized 1:1 into two arms: (i) metformin extended-release (ER) dose escalation to 2,000 mg over 14 days followed by combination with pembrolizumab 200 mg every 3 weeks or (ii) pembrolizumab 200 mg every 3 weeks followed by combination with metformin ER 2,000 mg daily. The primary endpoint was ORR per RECIST 1.1. Nineteen evaluable patients were planned to estimate the proportion of approximately 32% ORR. Safety was evaluated according to Common Terminology Criteria for Adverse Events v5.0. The distribution, activation, and cytotoxic function of NK cells were analyzed via flow cytometry. RESULTS: Twenty-one patients were enrolled; 76% were male, 52% were smokers, and the median age was 64 years. Ten patients had oropharyngeal tumors, of which nine were p16+. Eighteen patients were evaluable for response, including four complete and five partial responses for an ORR of 50% [95% confidence interval (29-71)]. Combination therapy was well tolerated with no unexpected adverse events (AE). Five grade 3 AEs occurred: nausea, diarrhea, fatigue, and weight loss. Metformin led to increased peripheral NK-cell maturation and cytotoxic ability. CONCLUSIONS: The combination of metformin and pembrolizumab was well tolerated with mild gastrointestinal AEs and promising activity, warranting further investigation in a randomized trial.
Senescent fibroblasts drive CD8+ T cell dysfunction in colorectal cancer via CD36-mediated lipid transfer and peroxidation.
BACKGROUND: Functional exhaustion of tumor-infiltrating CD8+ T cells represents a hallmark of colorectal cancer (CRC) immunosuppression, though its mechanistic drivers remain elusive. Given the established correlation between CRC progression and stromal senescence characterized by pathological lipid accumulation and impaired immunity, we investigated whether and how senescent fibroblasts actively regulate CD8+ T cell dysfunction. METHODS: Single-cell RNA sequencing (scRNA-seq) analysis was conducted to unveil the diverse fibroblast populations and the significant lipid metabolism changes between senescent fibroblasts and non-senescent fibroblasts in human CRC specimens and adjacent normal mucosa. Machine-learning identified senescent fibroblasts with a distinct gene signature. Cell-cell communication analysis was used to evaluate the interactions between senescent fibroblasts and CD8+ T cells in colorectal cancer. Co-culture experiments were conducted among senescent fibroblasts, CD8+ T cells and patient-derived organoids of CRC (CRC-PDOs), with the results evaluated with high-content imaging and propidium iodide/Hoechst 33,342 staining. Flow cytometry, ELISA and lipid pulse-chase with BODIPY FL C16 were performed to detect the alterations of CD8+ T cell cytotoxic function and metabolic status. AOM/DSS-induced CRC mouse model was used to conduct in vivo validation to evaluate whether senolytics could suppress CRC progression. Patients from the Cancer Genome Atlas colorectal cancer cohort were stratified into CD36-high and CD36-low groups by median expression, and drug sensitivity for GDSC2 compounds was predicted computationally using the oncoPredict R package. RESULTS: ScRNA-seq demonstrated the specific cell population presence and divergence of senescent fibroblasts between neoplastic and histologically normal adjacent cell clusters in CRC. Random Forest was employed for cell senescence classification. Feature importance analysis identified five genes as key contributors to the model’s decision process. Cell-cell communication analysis revealed enhanced interactions between senescent fibroblasts and CD8+ T cells in CRC. Co-culture of senescent fibroblasts significantly impaired the cytotoxic functions of CD8+ T cells on CRC-PDOs, which was reflected by the declined proportions of granzyme B (GZMB) + and interferon gamma (IFNγ) + CD8+ T cells and enhanced viability of CRC-PDOs. Mechanistically, the co-culture with senescent fibroblasts promoted the lipid shuttling into CD8+ T cells to induce lipid peroxidation and downstream impairment of cytotoxicity. Furthermore, the inhibition of CD36, the specific scavenger receptor for lipid uptake of CD8+ T cells, effectively suppressed lipid transfer and peroxidation thereby preserving the effector functions of CD8+ T cells and ultimately promoting tumor apoptosis. Complementarily, in vivo senolytic treatment significantly suppressed CRC progression in AOM-DSS CRC mouse models. Top 12 therapeutic agents were identified significantly enhanced predicted efficacy in CD36-high tumors. CONCLUSIONS: Our study identified a substantial population of senescent fibroblasts in human CRC through single cell transcriptomics, machine-learning and clinical biopsies. These senescent fibroblasts impair CD8+ T cell-mediated killing of CRC-PDOs via CD36-dependent lipid transfer, suggesting senolytic targeting of stromal cells as a promising immunotherapeutic strategy for CRC.