4-1BB-Enhanced Expansion of CD8+ TIL from Triple-Negative Breast Cancer Unveils Mutation-Specific CD8+ T Cells

Ferroptosis heterogeneity within the tumor microenvironment revealed a genetic blueprint of breast cancer

The tumor microenvironment (TME) significantly influences disease progression through immune infiltration, while ferroptosis, a recently discovered cell death mechanism, plays a crucial role in tumor suppression. However, its role in breast cancer is not clear. In this study, we analyzed bulk RNA and single-cell RNA sequencing data from 1217 samples, including 1104 breast cancer patients and 113 controls, to identify ferroptosis-related genes (FRGs) and construct a prognostic model. Using univariate cox regression, LASSO regression, and multivariate cox regression analysis, we discovered 21 FRGs and 3 TME-related immune cell types with prognostic value. Dimensionality reduction clustering and visualization were performed using the UMAP method, while the immune infiltration process was calculated with the TIP online tool. We employed GSEA enrichment analysis, WGCNA clustering analysis, and correlation analysis to examine functional differences, and the mutation analysis of the best and worst prognosis groups was conducted using the maftools package. Our findings revealed that knocking down the expression of the hub gene SLC39A7 significantly impacted cancer cell apoptosis and combining ferroptosis and TME scores yielded high prognostic power. Epithelial cells and B cells exhibited higher ferroptosis scores, which were independently associated with immune checkpoint blockade (ICB) response and ICB gene expression. This study provides a foundation for further exploration of the relationship between ferroptosis and ICB response in breast cancer. In conclusion, we developed a prognostic model based on ferroptosis and infiltrated immune cells that effectively stratified breast cancer patients and demonstrated the role of SLC39A7 in breast cancer pathogenesis through the regulation of apoptosis.

Identification of prognostic biomarkers of breast cancer based on the immune-related gene module

Breast cancer (BC) is highly malignant and its mortality rate remains high. The development of immunotherapy has gradually improved the prognosis and survival rate of patients. Therefore, identifying molecular markers concerned with BC immunity is of great importance for the treatment of this disease. The Cancer Genome Atlas-breast invasive carcinoma (TCGA-BRCA) was utilized as the training set while the BC expression dataset from the gene expression omnibus database was taken as the validation set here. Weighted gene co-expression network analysis combined with Pearson analysis and Tumor immune estimation resource (TIMER) was used to obtain immune cell-related hub gene module. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed on this module. Then, receiver operating characteristic curves combining Kaplan-Meier was used to evaluate the effectiveness of the model. Feature genes were screened and the independence of risk score was evaluated by univariate and multivariate Cox analyses. Differences in immune characteristics were analyzed via single-sample gene set enrichment analysis and CIBERSORT, and differences in gene mutation frequency were assessed via GenVisR analysis. Finally, the expression levels of prognostic feature genes in BC cells were validated by quantitative reverse transcription polymerase chain reaction (qRT-PCR). In this study, cell immune-related gene modules in TCGA-BRCA were successfully excavated, and a five-gene (TNFRSF14, NFKBIA, DLG3, IRF2, and CYP27A1) prognostic model was established. The prognostic model could effectively forecast the prognosis and survival rate of BC patients. The result showed that human leukocyte antigen-related proteins and macrophage M2 scores were remarkably highly expressed in the high-risk group, whereas CD8+ T cells, natural killer cells, M1, and other anti-tumor cells were lowly expressed. The model could be used as an independent prognostic factor to predict the prognosis of BC patients. The results of qRT-PCR validation were consistent with the results in the database, that is, except DLG3, the other four feature genes were lowly expressed in BC. The five-gene model established in this study can predict the prognostic and immune mode of BC patients effectively, which is anticipated to become a feasible molecular target for BC therapy.

Application of platform process development approaches to the manufacturing of Mabcalin™ bispecifics

Bispecific biotherapeutics offer potent and highly specific treatment options in oncology and immuno-oncology. However, many bispecific formats are prone to high levels of aggregation and instability, leading to prolonged development timelines, inefficient manufacturing, and high costs. The novel class of Mabcalin™ molecules consist of Anticalin® proteins fused to an IgG and are currently being evaluated in pre-clinical and clinical studies. Here, we describe a robust high-yield manufacturing platform for these therapeutic fusion proteins providing data up to commercially relevant scales. A platform upstream process was established for one of the Mabcalin bispecifics and then applied to other clinically relevant drug candidates with different IgG target specificities. Process performance was compared in 3 L bioreactors and production was scaled-up to up to 1000 L for confirmation. The Mabcalin proteins' structural and biophysical similarities enabled a downstream platform approach consisting of initial protein A capture, viral inactivation, mixed-mode anion exchange polishing, second polishing by cation exchange or hydrophobic interaction chromatography, viral filtration, buffer exchange and concentration by ultrafiltration/diafiltration. All three processes met their target specifications and achieved comparable clearance of impurities and product yields across scales. The described platform approach provides a fast and economic path to process confirmation and is well comparable to classical monoclonal antibody approaches in terms of costs and time to clinic.

Tumor-Infiltrating Lymphocytes and Adoptive Cell Therapy: State of the Art in Colorectal, Breast and Lung Cancer

Our knowledge of tumor-infiltrating lymphocytes (TILs) is dramatically expanding. These cells have proven prognostic and therapeutic value for many cancer outcomes and potential to treat also disseminated breast, colorectal, or lung cancer. However, the therapeutical outcome of TILs is negatively affected by tumor mutational burden and neoantigens. On the other hand, it can be improved in combination with checkpoint blockade therapy. This knowledge and rapid detection techniques alongside gene editing allow us to classify and modify T cells in many ways. Hence, to tailor them precisely to the patient´s needs as to program T cell receptors to recognize specific tumor-associated neoantigens and to insert them into lymphocytes or to select tumor neoantigen-specific T cells, for the development of vaccines that recognize tumor-specific antigens in tumors or metastases. Further studies and clinical trials in the field are needed for an even better-detailed understanding of TILs interactions and aiming in the fight against multiple cancers.

Identification of an exosome-related signature associated with prognosis and immune infiltration in breast cancer

Exosomes, nanosized vesicles, play a vital role in breast cancer (BC) occurrence, development, and drug resistance. Hence, we proceeded to study the potential prognostic value of exosome-related genes and their relationship to the immune microenvironment in BC. 121 exosome-related genes were provided by the ExoBCD database, and 7 final genes were selected to construct the prognostic signature. Besides, the expression levels of the 7 exosome-related genes were validated by the experiment in BC cell lines. Based on the signature, BC patients from the training and validation cohorts were separated into low- and high-risk groups. Subsequently, the R clusterProfiler package was applied to identify the distinct enrichment pathways between high-risk groups and low-risk groups. The relevance of the tumor immune microenvironment and exosome-related gene risk score were analyzed in BC. Eventually, the different expression levels of immune checkpoint-related genes were compared between the two risk groups. Based on the risk model, the low-risk groups were identified with a higher survival rate both in the training and validation cohorts. A better overall survival was revealed in patients with higher scores evaluated by the estimation of stromal and immune cells in malignant tumor tissues using expression (ESTIMATE) algorithm. Subsequently, BC patients with lower risk scores were indicated by higher expression levels of some immune checkpoint-related genes and immune cell infiltration. Exosomes are closely associated with the prognosis and immune cell infiltration of BC. These findings may contribute to improving immunotherapy and provide a new vision for BC treatment strategies.

A novel 4-1BB/HER2 bispecific antibody shows potent antitumor activities by increasing and activating tumor-infiltrating T cells

Resistance to HER2-targeted therapy narrows the efficacy of cancer immunotherapy. Although 4-1BB/CD137 is a promising drug target as a costimulatory molecule of immune cells, no therapeutic drug has been approved in the clinic because of systemic toxicity or limited efficacy. Previously, we developed a humanized anti-HER2 monoclonal antibody (mAb) HuA21 and anti-4-1BB mAb HuB6 with distinct antigen epitopes for cancer therapy. Here, we generated an Fc-muted IgG4 HER2/4-1BB bispecific antibody (BsAb) HK006 by the fusion of HuB6 scFv and HuA21 Fab. HK006 exhibited synergistic antitumor activity by blocking HER2 signal transduction and stimulating the 4-1BB signaling pathway simultaneously and strictly dependent on HER2 expression in vitro and in vivo. Strikingly, HK006 treatment enhanced antitumor immunity by increasing and activating tumor-infiltrating T cells. Moreover, HK006 did not induce nonspecific production of proinflammatory cytokines and had no obvious toxicity in mice. Overall, these data demonstrated that HK006 should be a promising candidate for HER2-positive cancer immunotherapy.

An Fc-muted bispecific antibody targeting PD-L1 and 4-1BB induces antitumor immune activity in colorectal cancer without systemic toxicity

BACKGROUND

Resistance to immune checkpoint inhibitor (ICI) therapy narrows the efficacy of cancer immunotherapy. Although 4-1BB is a promising drug target as a costimulatory molecule of immune cells, no 4-1BB agonist has been given clinical approval because of severe liver toxicity or limited efficacy. Therefore, a safe and efficient immunostimulatory molecule is urgently needed for cancer immunotherapy.

METHODS

HK010 was generated by antibody engineering, and the Fab/antigen complex structure was analyzed using crystallography. The affinity and activity of HK010 were detected by multiple in vitro bioassays, including enzyme-linked immunosorbent assay (ELISA), surface plasmon resonance (SPR), flow cytometry, and luciferase-reporter assays. Humanized mice bearing human PD-L1-expressing MC38 (MC38/hPDL1) or CT26 (CT26/hPDL1) tumor transplants were established to assess the in vivo antitumor activity of HK010. The pharmacokinetics (PK) and toxicity of HK010 were evaluated in cynomolgus monkeys.

RESULTS

HK010 was generated as an Fc-muted immunoglobulin (Ig)G4 PD-L1x4-1BB bispecific antibody (BsAb) with a distinguished Fab/antigen complex structure, and maintained a high affinity for human PD-L1 (KD: 2.27 nM) and low affinity for human 4-1BB (KD: 493 nM) to achieve potent PD-1/PD-L1 blockade and appropriate 4-1BB agonism. HK010 exhibited synergistic antitumor activity by blocking the PD-1/PD-L1 signaling pathway and stimulating the 4-1BB signaling pathway simultaneously, and being strictly dependent on the PD-L1 receptor in vitro and in vivo. In particular, when the dose was decreased to 0.3 mg/kg, HK010 still showed a strong antitumor effect in a humanized mouse model bearing MC38/hPDL1 tumors. Strikingly, HK010 treatment enhanced antitumor immunity and induced durable antigen-specific immune memory to prevent rechallenged tumor growth by recruiting CD8+ T cells and other lymphocytes into tumor tissue and activating tumor-infiltrating lymphocytes. Moreover, HK010 not only did not induce nonspecific production of proinflammatory cytokines but was also observed to be well tolerated in cynomolgus monkeys in 5 week repeated-dose (5, 15, or 50 mg/kg) and single-dose (75 or 150 mg/kg) toxicity studies.

CONCLUSION

We generated an Fc-muted anti-PD-L1x4-1BB BsAb, HK010, with a distinguished structural interaction with PD-L1 and 4-1BB that exhibits a synergistic antitumor effect by blocking the PD-1/PD-L1 signaling pathway and stimulating the 4-1BB signaling pathway simultaneously. It is strictly dependent on the PD-L1 receptor with no systemic toxicity, which may offer a new option for cancer immunotherapy.

Galectin functions in cancer-associated inflammation and thrombosis

Galectins are carbohydrate-binding proteins that regulate many cellular functions including proliferation, adhesion, migration, and phagocytosis. Increasing experimental and clinical evidence indicates that galectins influence many steps of cancer development by inducing the recruitment of immune cells to the inflammatory sites and modulating the effector function of neutrophils, monocytes, and lymphocytes. Recent studies described that different isoforms of galectins can induce platelet adhesion, aggregation, and granule release through the interaction with platelet-specific glycoproteins and integrins. Patients with cancer and/or deep-venous thrombosis have increased levels of galectins in the vasculature, suggesting that these proteins could be important contributors to cancer-associated inflammation and thrombosis. In this review, we summarize the pathological role of galectins in inflammatory and thrombotic events, influencing tumor progression and metastasis. We also discuss the potential of anti-cancer therapies targeting galectins in the pathological context of cancer-associated inflammation and thrombosis.

Current Situation and Prospect of Adoptive Cellular Immunotherapy for Malignancies

Adoptive cell immunotherapy (ACT) is an innovative promising treatment for tumors. ACT is characterized by the infusion of active anti-tumor immune cells (specific and non-specific) into patients to kill tumor cells either directly or indirectly by stimulating the body's immune system. The patient's (autologous) or a donor's (allogeneic) immune cells are used to improve immune function. Chimeric antigen receptor (CAR) T cells (CAR-T) is a type of ACT that has gained attention. T cells from the peripheral blood are genetically engineered to express CARs that rapidly proliferate and specifically recognize target antigens to exert its anti-tumor effects. Clinical application of CAR-T therapy for hematological tumors has shown good results, but adverse reactions and recurrence limit its applicability. Tumor infiltrating lymphocyte (TIL) therapy is effective for solid tumors. TIL therapy exhibits T cell receptor (TCR) clonality, superior tumor homing ability, and low targeted toxicity, but its successful application is limited to a number of tumors. Regardless, TIL and CAR-T therapies are effective for treating cancer. Additionally, CAR-natural killer (NK), CAR-macrophages (M), and TCR-T therapies are currently being researched. In this review, we highlight the current developments and limitations of several types of ACT.

Targeting Co-Stimulatory Receptors of the TNF Superfamily for Cancer Immunotherapy

The clinical approval of immune checkpoint inhibitors is an important advancement in the field of cancer immunotherapy. However, the percentage of beneficiaries is still limited and it is becoming clear that combination therapies are required to further enhance the treatment efficacy. The potential of strategies targeting the immunoregulatory network by "hitting the gas pedal" as opposed to "blocking the brakes" is being recognized and intensively investigated. Hence, next to immune checkpoint inhibitors, agonists of co-stimulatory receptors of the tumor necrosis factor superfamily (TNF-SF) are emerging as promising options to expand the immunomodulatory toolbox. In this review the development of different categories of recombinant antibody and ligand-based agonists of 4-1BB, OX40, and GITR is summarized and discussed in the context of the challenges presented by the structural and mechanistical features of the TNFR-SF. An overview of current formats, trends, and clinical studies is provided.

The PD-L1/4-1BB Bispecific Antibody-Anticalin Fusion Protein PRS-344/S095012 Elicits Strong T-Cell Stimulation in a Tumor-Localized Manner

PURPOSE

While patients responding to checkpoint blockade often achieve remarkable clinical responses, there is still significant unmet need due to resistant or refractory tumors. A combination of checkpoint blockade with further T-cell stimulation mediated by 4-1BB agonism may increase response rates and durability of response. A bispecific molecule that blocks the programmed cell death 1 (PD-1)/programmed cell death 1 ligand 1 (PD-L1) axis and localizes 4-1BB costimulation to a PD-L1-positive (PD-L1+) tumor microenvironment (TME) or tumor draining lymph nodes could maximize antitumor immunity and increase the therapeutic window beyond what has been reported for anti-4-1BB mAbs.

EXPERIMENTAL DESIGN

We generated and characterized the PD-L1/4-1BB bispecific molecule PRS-344/S095012 for target binding and functional activity in multiple relevant in vitro assays. Transgenic mice expressing human 4-1BB were transplanted with human PD-L1-expressing murine MC38 cells to assess in vivo antitumoral activity.

RESULTS

PRS-344/S095012 bound to its targets with high affinity and efficiently blocked the PD-1/PD-L1 pathway, and PRS-344/S095012-mediated 4-1BB costimulation was strictly PD-L1 dependent. We demonstrated a synergistic effect of both pathways on T-cell stimulation with the bispecific PRS-344/S095012 being more potent than the combination of mAbs. PRS-344/S095012 augmented CD4-positive (CD4+) and CD8-positive (CD8+) T-cell effector functions and enhanced antigen-specific T-cell stimulation. Finally, PRS-344/S095012 demonstrated strong antitumoral efficacy in an anti-PD-L1-resistant mouse model in which soluble 4-1BB was detected as an early marker for 4-1BB agonist activity.

CONCLUSIONS

The PD-L1/4-1BB bispecific PRS-344/S095012 efficiently combines checkpoint blockade with a tumor-localized 4-1BB-mediated stimulation burst to antigen-specific T cells, more potent than the combination of mAbs, supporting the advancement of PRS-344/S095012 toward clinical development. See related commentary by Shu et al., p. 3182.

Highly efficient PD-1-targeted CRISPR-Cas9 for tumor-infiltrating lymphocyte-based adoptive T cell therapy

Adoptive T cell therapy (ACT) with expanded tumor-infiltrating lymphocytes (TIL) can induce durable responses in cancer patients from multiple histologies, with response rates of up to 50%. Antibodies blocking the engagement of the inhibitory receptor programmed cell death protein 1 (PD-1) have been successful across a variety of cancer diagnoses. We hypothesized that these approaches could be combined by using CRISPR-Cas9 gene editing to knock out PD-1 in TILs from metastatic melanoma and head-and-neck, thyroid, and colorectal cancer. Non-viral, non-plasmid-based PD-1 knockout was carried out immediately prior to the traditional 14-day TIL-based ACT rapid-expansion protocol. A median 87.53% reduction in cell surface PD-1 expression was observed post-expansion and confirmed at the genomic level. No off-target editing was detected, and PD-1 knockout had no effect on final fold expansion. Edited cells exhibited few phenotypic differences and matched control functionality. Pre-clinical-scale results were confirmed at a clinical scale by generating a PD-1-deficient TIL product using the good manufacturing practice facilities, equipment, procedures, and starting material used for standard patient treatment. Our results demonstrate that simple, non-viral, non-plasmid-based CRISPR-Cas9 methods can be feasibly adopted into a TIL-based ACT protocol to produce treatment products deficient in molecules such as PD-1, without any evident negative effects.

Soluble CD137 as a dynamic biomarker to monitor agonist CD137 immunotherapies

Background

On the basis of efficacy in mouse tumor models, multiple CD137 (4-1BB) agonist agents are being preclinically and clinically developed. The costimulatory molecule CD137 is inducibly expressed as a transmembrane or as a soluble protein (sCD137). Moreover, the CD137 cytoplasmic signaling domain is a key part in approved chimeric antigen receptors (CARs). Reliable pharmacodynamic biomarkers for CD137 ligation and costimulation of T cells will facilitate clinical development of CD137 agonists in the clinic.

Methods

We used human and mouse CD8 T cells undergoing activation to measure CD137 transcription and protein expression levels determining both the membrane-bound and soluble forms. In tumor-bearing mice plasma sCD137 concentrations were monitored on treatment with agonist anti-CD137 monoclonal antibodies (mAbs). Human CD137 knock-in mice were treated with clinical-grade agonist anti-human CD137 mAb (Urelumab). Sequential plasma samples were collected from the first patients intratumorally treated with Urelumab in the INTRUST clinical trial. Anti-mesothelin CD137-encompassing CAR-transduced T cells were stimulated with mesothelin coated microbeads. sCD137 was measured by sandwich ELISA and Luminex. Flow cytometry was used to monitor CD137 surface expression.

Results

CD137 costimulation upregulates transcription and protein expression of CD137 itself including sCD137 in human and mouse CD8 T cells. Immunotherapy with anti-CD137 agonist mAb resulted in increased plasma sCD137 in mice bearing syngeneic tumors. sCD137 induction is also observed in human CD137 knock-in mice treated with Urelumab and in mice transiently humanized with T cells undergoing CD137 costimulation inside subcutaneously implanted Matrigel plugs. The CD137 signaling domain-containing CAR T cells readily released sCD137 and acquired CD137 surface expression on antigen recognition. Patients treated intratumorally with low dose Urelumab showed increased plasma concentrations of sCD137.

Conclusion

sCD137 in plasma and CD137 surface expression can be used as quantitative parameters dynamically reflecting therapeutic costimulatory activity elicited by agonist CD137-targeted agents.

Identification and validation of a twelve immune infiltration-related lncRNA prognostic signature for bladder cancer

The prognosis of bladder cancer patients is strongly related to both the immune-infiltrating cells and the expression of lncRNAs. In this study, we analyzed the infiltration of immune cells in 403 bladder cancer samples obtained from TCGA by applying the ssGSEA to these samples, then dividing them into high/low immune cell infiltration groups. Based on these groupings, we found 404 differentially expressed immune infiltration-related lncRNAs, which were successively analyzed by univariate Cox regression, then Least Absolute Shrinkage and Selection Operator (LASSO), and finally stepwise multiple Cox regression. Then 12 differentially expressed immune infiltration-related lncRNAs were identified and used to construct a prognostic signature for bladder cancer. Subsequently, Kaplan-Meier analysis, univariate Cox regression, multivariate Cox regression, and multivariate time-dependent ROC analyses (for 1, 3, 5 years) all revealed that this signature performed well in predicting overall survival and served as an independent prognostic factor for patients with bladder cancer. Finally, both TIMER and CIBESORT showed that this 12-lncRNA prognostic signature for bladder cancer was associated with the infiltration of immune cell subtypes. Besides, nomogram considered risk score and clinical characteristics was assembled and showed great performance. More importantly, we found our signature could well distinguish the drug response of patients with bladder cancer. High risk patients showed a better response to cisplatin, doxorubicin, and anti- CTLA4 immunotherapy, low risk patients showed a better response to methotrexate and anti-PD1 immunotherapy compared with each other.

Isolation and Maintenance of Tumor-Infiltrating Lymphocytes for Translational and Clinical Applications: Established Methods and New Developments

Adoptive cell transfer (ACT) of in vitro expanded tumor-infiltrating lymphocytes (TIL) for the treatment of patients with advanced stages of metastatic melanoma remains one of the most beneficial therapies eliciting long-lasting responses. Methods and protocols used to expand TIL have evolved over time, utilizing different culture devices and other tools, to streamline and maximize the end product in both numbers and quality. Summarized in this chapter are the latest protocols used in the TIL program at MDACC.

EZH2 Inhibition Compromises α4-1BB-Mediated Antitumor Efficacy by Reducing the Survival and Effector Programming of CD8+ T Cells

Enhancer of Zeste Homolog 2 (EZH2) inhibitors (EZH2i) are approved to treat certain cancer types. Previous studies have suggested the potential to combine EZH2i with immune checkpoint blockade targeting coinhibitory receptors like PD-(L)1 and CTLA-4, but whether it can also enhance the activity of agents targeting costimulatory receptors is not known. Here, we explore the combination between EZH2i and an agonist antibody targeting the T cell costimulatory receptor 4-1BB (α4-1BB). Our data show that EZH2i compromise the efficacy of α4-1BB in both CT26 colon carcinoma and in an in vivo protein immunization model. We link this to reduced effector survival and increased BIM expression in CD8+ T cells upon EZH2i treatment. These data support the requirement of EZH2 function in 4-1BB-mediated CD8+ T cell expansion and effector programming and emphasize the consideration that must be given when combining such antitumoral therapies.

m6A-Mediated Tumor Invasion and Methylation Modification in Breast Cancer Microenvironment

Background

We analyzed the n6-methyladenosine (m6A) modification patterns of immune cells infiltrating the tumor microenvironment of breast cancer (BC) to provide a new perspective for the early diagnosis and treatment of BC.

Methods

Based on 23 m6A regulatory factors, we identified m6A-related gene characteristics and m6A modification patterns in BC through unsupervised cluster analysis. To examine the differences in biological processes among various m6A modification modes, we performed genomic variation analysis. We then quantified the relative infiltration levels of different immune cell subpopulations in the tumor microenvironment of BC using the CIBERSORT algorithm and single-sample gene set enrichment analysis. Univariate Cox analysis was used to screen for m6A characteristic genes related to prognosis. Finally, we evaluated the m6A modification pattern of patients with a single BC by constructing the m6Ascore based on principal component analysis.

Results

We identified three different m6A modification patterns in 2128 BC samples. A higher abundance of the immune infiltration of the m6Acluster C was indicated by the results of CIBERSORT and the single-sample gene set enrichment analysis. Based on the m6A characteristic genes obtained through screening, the m6Ascore was determined. The BC patients were segregated into m6Ascore groups of low and high categories, which revealed significant survival benefits among patients with low m6Ascores. Additionally, the high-m6Ascore group had a higher mutation frequency and was associated with low PD-L1 expression, and the m6Ascore and tumor mutation burden showed a positive correlation. In addition, treatment effects were better in patients in the high-m6Ascore group.

Conclusions

In case of a single patient with BC, the immune cell infiltration characteristics of the tumor microenvironment and the m6A methylation modification pattern could be evaluated using the m6Ascore. Our results provide a foundation for improving personalized immunotherapy of BC.

Adoptive cell therapy with tumor-infiltrating lymphocytes supported by checkpoint inhibition across multiple solid cancer types

Background

Adoptive cell therapy (ACT) with tumor-infiltrating lymphocytes (TILs) has shown remarkable results in malignant melanoma (MM), while studies on the potential in other cancer diagnoses are sparse. Further, the prospect of using checkpoint inhibitors (CPIs) to support TIL production and therapy remains to be explored.

Study design

TIL-based ACT with CPIs was evaluated in a clinical phase I/II trial. Ipilimumab (3 mg/kg) was administered prior to tumor resection and nivolumab (3 mg/kg, every 2 weeks ×4) in relation to TIL infusion. Preconditioning chemotherapy was given before TIL infusion and followed by low-dose (2 10e6 international units (UI) ×1 subcutaneous for 14 days) interleukin-2 stimulation.

Results

Twenty-five patients covering 10 different cancer diagnoses were treated with in vitro expanded TILs. Expansion of TILs was successful in 97% of recruited patients. Five patients had sizeable tumor regressions of 30%–63%, including two confirmed partial responses in patients with head-and-neck cancer and cholangiocarcinoma. Safety and feasibility were comparable to MM trials of ACT with the addition of expected CPI toxicity. In an exploratory analysis, tumor mutational burden and expression of the alpha-integrin CD103 (p=0.025) were associated with increased disease control. In vitro tumor reactivity was seen in both patients with an objective response and was associated with regressions in tumor size (p=0.028).

Conclusion

High success rates of TIL expansion were demonstrated across multiple solid cancers. TIL ACTs were found feasible, independent of previous therapy. Tumor regressions after ACT combined with CPIs were demonstrated in several cancer types supported by in vitro antitumor reactivity of the TILs.

Trial registration numbers

NCT03296137, and EudraCT No. 2017-002323-25.

Landscape of Immune Microenvironment Under Immune Cell Infiltration Pattern in Breast Cancer

Background

Increasing evdence supports the suggestion that the immune cell infiltration (ICI) patterns play a pivotal role in tumor progression in breast cancer (BRCA). Nonetheless, there has been no comprehensive analysis of the ICI patterns effects on the clinical outcomes and immunotherapy.

Methods

Multiomic data for BRCA samples were downloaded from TCGA. ESTIMATE algorithm, ssGSEA method, and CIBERSORT analysis were used to uncover the landscape of the tumor immune microenvironment (TIME). BRCA subtypes based on the ICI pattern were identified by consensus clustering and principal-component analysis was performed to obtain the ICI scores to quantify the ICI patterns in individual tumors. Their prognostic value was validated by the Kaplan-Meier survival curves. Gene set enrichment analysis (GSEA) was applied for functional annotation. Immunophenoscore (IPS) was employed to explore the immunotherapeutic role of the ICI scores. Finally, the mutation data was analyzed by using the “maftools” R package.

Results

Three different immune infiltration patterns with a distinct prognosis and biological signature were recognized among 1,198 BRCA samples. The characteristics of TIME under these three patterns were highly consistent with three known immune profiles: immune- excluded, immune-desert, and immune-inflamed phenotypes, respectively. The identification of the ICI patterns within individual tumors based on the ICI score, developed under the ICI-related signature genes, contributed into dissecting biological processes, clinical outcome, immune cells infiltration, immunotherapeutic effect, and genetic variation. High ICI score subtype, characterized with a suppression of immunity, suggested an immune-exhausted phenotype. Abundant effective immune cells were discovered in the low ICI score patients, which corresponded to an immune-activated phenotype and might present an immunotherapeutic advantage. Immunophenoscore was implemented as a surrogate of immunotherapeutic outcome, low-ICI scores samples obtained a significantly higher immunophenoscore. Enrichment of the JAK/STAT and VEGF signal pathways were activated in the ICI low-score subgroup. Finally, the synergistic effect between the ICI score and the tumor mutation burden (TMB) was confirmed.

Conclusion

This work comprehensively elucidated that the ICI patterns served as an indispensable player in complexity and diversity of TIME. Quantitative identification of the ICI patterns in individual tumor will contribute into mapping the landscape of TIME further optimizing precision immunotherapy.

ACT Up TIL Now: The Evolution of Tumor-Infiltrating Lymphocytes in Adoptive Cell Therapy for the Treatment of Solid Tumors

The past decades of cancer immunotherapy research have provided profound evidence that the immune system is capable of inducing durable tumor regression. Although many commercialized anti-cancer immunotherapies are available to patients, these treatment options only scrape the surface of the potential immune-related treatment possibilities for cancer. Additionally, many individuals are ineligible for established immunotherapies due to their cancer type. The adoptive cell transfer of autologous tumor-infiltrating lymphocytes has been used in humans for over 30 years to treat metastatic melanoma, and continued modifications are making it increasingly more effective against other types of cancer. This comprehensive review outlines this therapy from its infancy through to the present day, bringing to light modifications and optimizations to the traditional workflow, as well as highlighting the influence of new methods and technologies.

Formosanin C promotes the curative efficacy of ultrasound-guided radiofrequency ablation in a mouse model of breast cancer

Breast cancer is the leading cause of tumor-associated death among women worldwide, and new therapeutic strategies are required to improve the post-surgery prognosis and quality of life of patients. Radiofrequency ablation (RFA) is a less invasive approach compared with traditional surgical resection to treat malignancies, and the combination of RFA and chemotherapeutic agents, including formosanin C (FC), can synergistically improve the curative effects against breast carcinoma. However, the detailed mechanisms remain unclear. In the present study, nude mice were used to identify the influence of FC on the therapeutic efficacy of RFA for breast cancer. Flow cytometry was performed to demonstrate the proportional alteration of CD8⁺ and CD45⁺ T cells with different biomarkers, including CD107a, IFNγ and TNFα. It was demonstrated that FC enhanced the therapeutic efficacy of RFA in breast cancer, while RFA combined with FC improved the proportion of IFNγ⁺ and TNFα⁺ CD8⁺ T cells and CD107a⁺ CD8⁺ T cells in tumor-infiltrating lymphocytes, thus increasing the immune responses caused by surgery and chemotherapy. The present study indicated that FC may promote the curative efficacy of ultrasound-guided RFA against breast tumor by regulating adaptive immune responses.

Tackling Immune Targets for Breast Cancer: Beyond PD-1/PD-L1 Axis

The burden of breast cancer is imposing a huge global problem. Drug discovery research and novel approaches to treat breast cancer have been carried out extensively over the last decades. Although immune checkpoint inhibitors are showing promising preclinical and clinical results in treating breast cancer, they are facing multiple limitations. From an immunological perspective, a recent report highlighted breast cancer as an "inflamed tumor" with an immunosuppressive microenvironment. Consequently, researchers have been focusing on identifying novel immunological targets that can tune up the tumor immune microenvironment. In this context, several novel non-classical immune targets have been targeted to determine their ability to uncouple immunoregulatory pathways at play in the tumor microenvironment. This article will highlight strategies designed to increase the immunogenicity of the breast tumor microenvironment. It also addresses the latest studies on targets which can enhance immune responses to breast cancer and discusses examples of preclinical and clinical trial landscapes that utilize these targets.

Synthetic TILs: Engineered Tumor-Infiltrating Lymphocytes With Improved Therapeutic Potential

Immunotherapy has emerged as an effective and life-changing approach for several types of cancers, both liquid and solid tumors. In combination with traditional treatments such as radiotherapy and/or chemotherapy, immune checkpoints inhibitors have improved prognosis and overall survival of patients with advanced melanoma and many other cancers. Among adoptive cell therapies (ACT), while chimeric antigen receptor T cell therapies have demonstrated remarkable efficacy in some hematologic malignancies, such as B cell leukemias, their success in solid tumors remains scarce due to the characteristics of the tumor microenvironment. On the other hand, ACT using tumor-infiltrating lymphocytes (TILs) is arguably the most effective treatment for metastatic melanoma patients, but even if their isolation has been achieved in epithelial tumors, their success beyond melanoma remains limited. Here, we review several aspects impacting TIL- and gene-modified “synthetic” TIL-based therapies and discuss future challenges that must be addressed with these approaches.

The Role of Immune Cells in Breast Tissue and Immunotherapy for the Treatment of Breast Cancer

Immune cells are present in normal breast tissue and in breast carcinoma. The nature and distribution of the immune cell subtypes in these tissues are reviewed to promote a better understanding of their important role in breast cancer prevention and treatment. We conducted a review of the literature to define the type, location, distribution, and role of immune cells in normal breast tissue and in in situ and invasive breast cancer. Immune cells in normal breast tissue are located predominantly within the epithelial component in breast ductal lobules. Immune cell subtypes representing innate immunity (NK, CD68+, and CD11c+ cells) and adaptive immunity (most commonly CD8+, but CD4+ and CD20+ as well) are present; CD8+ cells are the most common subtype and are primarily effector memory cells. Immune cells may recognize neoantigens and endogenous and exogenous ligands and may serve in chronic inflammation and immunosurveillance. Progression to breast cancer is characterized by increased immune cell infiltrates in tumor parenchyma and stroma, including CD4+ and CD8+ granzyme B+ cytotoxic T cells, B cells, macrophages and dendritic cells. Tumor-infiltrating lymphocytes in breast cancer may serve as prognostic indicators for response to chemotherapy and for survival. Experimental strategies of adoptive transfer of breast tumor-infiltrating lymphocyte may allow regression of metastatic breast cancer and encourage development of innovative T-cell strategies for the immunotherapy of breast cancer. In conclusion, immune cells in breast tissues play an important role throughout breast carcinogenesis. An understanding of these roles has important implications for the prevention and the treatment of breast cancer.

Identification and verification of an immune-related lncRNA signature for predicting the prognosis of patients with bladder cancer

BACKGROUND

Recent studies have revealed the significant roles of immune-related long noncoding RNAs (lncRNAs) in cancer development and progression. The identification of biomarkers that contribute to early detection and risk stratification provides significant benefits for bladder cancer (BC) patients. The current study aimed to determine an immune-related lncRNA signature for predicting the prognosis of BC patients.

METHODS

Based on The Cancer Genome Atlas (TCGA) database, we identified seven immune-related lncRNAs with prognostic value. The predictive value of the prognostic signature developed from immune-related lncRNAs was assessed by survival and nomogram analyses. Principal component analysis (PCA) was performed to visualize gene expression patterns in the groups defined by the risk score, and the immune composition and purity of the tumor were evaluated by the ESTIMATE algorithm.

RESULTS

Based on the Pearson correlation analysis results, 765 immune-related lncRNAs were filtered (|R| > 0.4, P < 0.001), and seven immune-related lncRNAs (Z84484.1, AC009120.2, AL450384.2, AC024060.1, TNFRSF14-AS1, AL354919.2, OCIAD1-AS1) with prognostic value were finally identified. Patients in the low-risk group had a better prognosis than those in the high-risk group. Multivariate Cox regression analysis showed that the signature was an independent prognostic factor. A prognostic nomogram with clinical features and the signature of seven immune-related lncRNAs was also constructed. According to the PCA and ESTIMATE algorithm results, we found different immune statuses in the low-and high-risk groups.

CONCLUSIONS

Our study shows that the signature of seven immune-related lncRNAs can be used as a prognostic marker for BC.

Immunotherapy for advanced thyroid cancers - rationale, current advances and future strategies

In the past decade, the field of cancer immunotherapy has been revolutionized by immune checkpoint blockade (ICB) technologies. Success across a broad spectrum of cancers has led to a paradigm shift in therapy for patients with advanced cancer. Early data are now accumulating in progressive thyroid cancers treated with single-agent ICB therapies and combination approaches that incorporate ICB technologies. This Review discusses our current knowledge of the immune response in thyroid cancers, the latest and ongoing immune-based approaches, and the future of immunotherapies in thyroid cancer. Physiologically relevant preclinical mouse models and human correlative research studies will inform development of the next stage of immune-based therapies for patients with advanced thyroid cancer.

CAR T-cell therapy for triple-negative breast cancer: Where we are

Triple-negative breast cancer (TNBC) is the most complex and challenging breast cancer subtype to treat, and chemotherapy remains the standard of care. Clinically, TNBC has a relatively high rate of recurrence and poor prognosis, which leads to a significant effort to discover novel strategies to treat patients with these tumors. Currently, chimeric antigen receptor (CAR) T cell-based immunotherapy redirects the patient's immune system directly to recognize and eradicate tumor-associated antigens (TAAs) expressing tumor cells being explored as a treatment for TNBC. A steadily increasing research in CAR T-cell therapy targeting different TAAs in TNBC has reported. In this review, we introduce the CAR technology and summarize the potential TAAs, available CARs, the antitumor activity, and the related toxicity of CARs currently under investigation for TNBC. We also highlight the potential strategies to prevent/reduce potential "on target, off tumor" toxicity induced by CAR T-cell therapy. This review will help to explore proper targets to expand further the CAR T-cell therapy for TNBCs in the clinic.

In vitro 4-1BB stimulation promotes expansion of CD8+ tumor-infiltrating lymphocytes from various sarcoma subtypes

Tumor-specific tumor-infiltrating lymphocytes (TILs) can be in vitro expanded and have the ability to induce complete and durable tumor regression in some patients with melanoma following adoptive cell therapy (ACT). In this preclinical study, we investigated the feasibility of expanding TIL from sarcomas, as well as performing functional in vitro analyses on these. TILs were expanded in vitro by the use of IL2 stimulation with or without the addition of 4-1BB and CD3 antibodies. Phenotypical and functional analyses were mainly performed by flow cytometry. TILs were expanded from 25 of 28 (89%) tumor samples from patients with 9 different sarcoma subtypes. TILs were predominantly αβ T-cells of effector memory subtype with CD4⁺  dominance. In particular, CD8⁺ TIL highly expressed LAG3 and to a lesser degree PD-1 and BTLA. In total, 10 of 20 TIL cultures demonstrated in vitro recognition of autologous tumor. In some cases, the fraction of tumor-reactive T cells was more than 20%. 4-1BB stimulation augmented expansion kinetics and favored CD8⁺ occurrence. In conclusion, TIL expansion from sarcoma is feasible and expanded TILs highly express LAG3 and comprise multifunctional tumor-reactive T-cells.

Identification and validation of immune-related lncRNA prognostic signature for breast cancer

The prognosis of patients with breast cancer is closely related to both the infiltration of immune cells and the expression of lncRNAs. In this study, we evaluated the infiltration of immune cells in 1109 breast cancer samples obtained from TCGA by applying the ssGSEA to the transcriptome of these samples, thereby generating high immune cell infiltration group and low immune cell infiltration group. On the basis of these groupings, we found 696 differentially expressed lncRNAs which were sequentially subjected to univariate Cox regression and stepwise multiple Cox regression analysis. 11 lncRNAs were identified as prognostic signature for breast cancer. Kaplan-Meier analysis, univariate Cox regression, multivariate Cox regression, and ROC analyses further revealed that this 11-lncRNA signature was a novel and important prognostic factor independent of multiple clinicopathological parameters. The TIMER database showed that this 11-lncRNA prognostic signature for breast cancer was associated with the infiltration of immune cell subtypes.

Potential clinical application of tumor-infiltrating lymphocyte therapy for ovarian epithelial cancer prior or post-resistance to chemotherapy

BACKGROUND

Immunotherapy has become a powerful treatment option for several solid tumor types. The presence of tumor-infiltrating lymphocytes (TIL) is correlated with better prognosis in ovarian cancer, pointing at the possibility to benefit from harnessing their anti-tumor activity. This preclinical study explores the feasibility of adoptive cell therapy (ACT) with TIL using an improved culture method.

METHODS

TIL from high-grade serous ovarian cancer were cultured using a combination of IL-2 with agonistic antibodies targeting 4-1BB and CD3. The cells were phenotyped using flow cytometry in the fresh tissue and after expansion. Tumor reactivity was assessed against HLA-matched ovarian cancer cell lines via IFN-γ ELISPOT.

RESULTS

Ovarian cancer is highly infiltrated with CD8⁺ TIL that are preferentially and robustly expanded with the addition of the agonistic antibodies. With a 95% success rate, the TIL are grown to ≥ 100 × 10⁶ cells in 2-3 weeks without over differentiation. In addition, the CD8⁺ TIL grown with this method showed HLA-restricted tumor recognition.

CONCLUSIONS

These results indicate the viability of TIL ACT for refractory ovarian cancer by allowing for the large expansion of anti-tumor TIL in a short time and consistent manner.

Utilizing T-cell Activation Signals 1, 2, and 3 for Tumor-infiltrating Lymphocytes (TIL) Expansion: The Advantage Over the Sole Use of Interleukin-2 in Cutaneous and Uveal Melanoma

In this study, we address one of the major critiques for tumor-infiltrating lymphocyte (TIL) therapy-the time needed for proper expansion of a suitable product. We postulated that T-cell receptor activation in the first phase of expansion combined with an agonistic stimulation of CD137/4-1BB and interleukin-2 would favor preferential expansion of CD8 TIL. Indeed, this novel 3-signal approach for optimal T-cell activation resulted in faster and more consistent expansion of CD8CD3 TIL. This new method allowed for successful expansion of TIL from cutaneous and uveal melanoma tumors in 100% of the cultures in <3 weeks. Finally, providing the 3 signals attributed to optimal T-cell activation led to expansion of TIL capable of recognizing their tumor counterpart in cutaneous and uveal melanoma. This new methodology for the initial phase of TIL expansion brings a new opportunity for translation of TIL therapy in challenging malignancies such as uveal melanoma.

Chimeric antigen receptor modified T cell (CAR-T) co-expressed with ICOSL-41BB promote CAR-T proliferation and tumor rejection

T cells edited by chimeric antigen receptors (CAR) have shown great potential in the treatment of tumors, especially malignant blood tumors. However, there remain many obstacles in the CAR-T therapy against solid tumors, such as the expansion of CAR-T cells ex vivo and the exhaustion of CAR-T cells in vivo. In order to solve these problems, we described a novel CAR which is targeting GPC3 by expressing CD28 co-stimulation domain and CD3z ITAM (G328z), meanwhile co-expressing ICOSL extracellular and transmembrane region fused with 41BB cytoplasmic domain (G328z-ICOSL-41BB). Compared with G328z, G328z-ICOSL-41BB fusion protein significantly reinforced the expansion ability of CAR-T cells ex vivo, and prolonged the survival time of mice with hepatocellular carcinoma. We now demonstrate that the enhancement of CAR-T cell activity is dependent on the enhanced PI3K signaling pathway and up-regulated expression of Bcl2 to inhibit apoptosis and promote proliferation of CAR-T cells. Besides, the CAR with ICOSL-41BB fusion protein have been strengthened significantly in comparison with fusing ICOSL protein only, which might be caused by the fact that ICOSL-41BB not only supplies ICOS signal for other cells, but also provides 41BB signal for itself. Consequently, CARs with ICOSL-41BB fusion protein could increase the therapeutic efficacy against solid tumors in vivo compared with the G328z CAR, which might further assist the development of potent and durable T cell therapeutics.

Tumor infiltrating lymphocytes expanded from pediatric neuroblastoma display heterogeneity of phenotype and function

Adoptive transfer of ex vivo expanded tumor infiltrating lymphocytes (TILs) has led to clinical benefit in some patients with melanoma but has not demonstrated convincing efficacy in other solid cancers. Whilst the presence of TILs in many types of cancer is often associated with better clinical prognosis, their function has not been systematically evaluated across cancer types. Responses to immunological checkpoint inhibitors in a wide range of cancers, including those for which adoptive transfer of expanded TILs has not shown clinical benefit, has clearly delineated a number of tumor type associated with tumor-reactive lymphocytes capable of effecting tumor remissions. Neuroblastoma is an aggressive childhood solid cancer in which immunotherapy with GD2-directed antibodies confers a proven survival advantage through incompletely understood mechanisms. We therefore evaluated the feasibility of ex vivo expansion of TILs from freshly resected neuroblastoma tumors and the potential therapeutic utility of TIL expansions. TILs were successfully expanded from both tumor biopsies or resections. Significant numbers of NKT and γδT cells were identified alongside the mixed population of cytotoxic (CD8⁺) and helper (CD4⁺) T cells of both effector and central memory phenotypes. Isolated TILs were broadly non-reactive against autologous tumor and neuroblastoma cell lines, so enhancement of neuroblastoma killing was attained by transducing TILs with a second-generation chimeric antigen receptor (CAR) targeting GD2. CAR-TILs demonstrated antigen-specific cytotoxicity against tumor cell lines. This study is the first to show reproducible expansion of TILs from pediatric neuroblastoma, the high proportion of innate-like lymphocytes, and the feasibility to use CAR-TILs therapeutically.

Serum amyloid A predisposes inflammatory tumor microenvironment in triple negative breast cancer

Acute-phase proteins (APPs) are associated with a variety of disorders such as infection, inflammatory diseases, and cancers. The signature profile of APPs in breast cancer (BC) is poorly understood. Here, we identified serum amyloid A (SAA) for proinflammatory predisposition in BC through the signature profiles of APPs, interleukin (IL) and tumor necrosis factor (TNF) superfamily using publicly available datasets of tumor samples and cell lines. Triple-negative breast cancer (TNBC) subtype highly expressed SAA1/2 compared to HER2, luminal A (LA) and luminal B (LB) subtypes. IL1A, IL1B, IL8/CXCL8, IL32 and IL27RA in IL superfamily and CD70, TNFSF9 and TNFRSF21 in TNF superfamily were highly expressed in TNBC compared to other subtypes. SAA is restrictedly regulated by nuclear factor (NF)-κB and IL-1β, an NF-κB activator highly expressed in TNBC, increased the promoter activity of SAA1 in human TNBC MDA-MB231 cells. Interestingly, two κB-sites contained in SAA1 promoter were involved, and the proximal region (-96/-87) was more critical than the distal site (-288/-279) in regulating IL-1β-induced SAA1. Among the SAA receptors, TLR1 and TLR2 were highly expressed in TNBC. Cu-CPT22, TLR1/2 antagonist, abrogated IL-1β-induced SAA1 promoter activity. In addition, SAA1 induced IL8/CXCL8 promoter activity, which was partially reduced by Cu-CPT22. Notably, SAA1/2, TLR2 and IL8/CXCL8 were associated with a poor overall survival in mesenchymal-like TNBC. Taken together, IL-1-induced SAA via NF-κB-mediated signaling could potentiate an inflammatory burden, leading to cancer progression and high mortality in TNBC patients.

Mitochondrial Morphological and Functional Reprogramming Following CD137 (4-1BB) Costimulation

T and NK lymphocytes express CD137 (4-1BB), a costimulatory receptor of the TNFR family whose function is exploitable for cancer immunotherapy. Mitochondria regulate the function and survival of T lymphocytes. Herein, we show that CD137 costimulation provided by agonist mAb and CD137L (4-1BBL) induced mitochondria enlargement that resulted in enhanced mitochondrial mass and transmembrane potential in human and mouse CD8⁺ T cells. Such mitochondrial changes increased T-cell respiratory capacities and were critically dependent on mitochondrial fusion protein OPA-1 expression. Mass and function of mitochondria in tumor-reactive CD8⁺ T cells from cancer-bearing mice were invigorated by agonist mAb to CD137, whereas mitochondrial baseline mass and function were depressed in CD137-deficient tumor reactive T cells. Tumor rejection induced by the synergistic combination of adoptive T-cell therapy and agonistic anti-CD137 was critically dependent on OPA-1 expression in transferred CD8⁺ T cells. Moreover, stimulation of CD137 with CD137 mAb in short-term cultures of human tumor-infiltrating lymphocytes led to mitochondria enlargement and increased transmembrane potential. Collectively, these data point to a critical link between mitochondrial morphology and function and enhanced antitumor effector activity upon CD137 costimulation of T cells. Cancer Immunol Res; 6(7); 798-811. ©2018 AACR.

The tumor microenvironment: Thousand obstacles for effector T cells

The immune system is endowed with the capability to recognize and destroy transformed cells, but even in the presence of an immune infiltrate many tumors do progress. In the last decades new discoveries have shed light into (some of) the underlying mechanisms. Immune effector cells are not only under the influence of immune suppressive cell subsets, but also intrinsically regulated by immune check point molecules that under physiological condition avoid attach of healthy tissue. Moreover, tumor cells are modifying the surrounding microenvironment through secretion of immune modulators as well as via their own metabolism, thus further impairing the development of immune effector functions. Different approaches are currently being evaluated in the clinic to overcome those regulatory mechanisms and to unleash effector T cells.

Expansion of tumor-infiltrating lymphocytes and their potential for application as adoptive cell transfer therapy in human breast cancer

Adoptive cell transfer (ACT) of ex vivo expanded tumor-infiltrating lymphocytes (TILs) has been successful in treating a considerable proportion of patients with metastatic melanoma. In addition, some patients with several other solid tumors were recently reported to have benefited clinically from such ACT. However, it remains unclear whether ACT using TILs is broadly applicable in breast cancer, the most common cancer in women. In this study, the utility of TILs as an ACT source in breast cancers was explored by deriving TILs from a large number of breast cancer samples and assessing their biological potentials. We successfully expanded TILs ex vivo under a standard TIL culture condition from over 100 breast cancer samples, including all breast cancer subtypes. We also found that the information about the percentage of TIL and presence of tertiary lymphoid structure in the tumor tissues could be useful for estimating the number of obtainable TILs after ex vivo culture. The ex vivo expanded TILs contained a considerable level of central memory phenotype T cells (about 20%), and a large proportion of TIL samples were reactive to autologous tumor cells in vitro. Furthermore, the in vitro tumor-reactive autologous TILs could also function in vivo in a xenograft mouse model implanted with the primary tumor tissue. Collectively, these results strongly indicate that ACT using ex vivo expanded autologous TILs is a feasible option in treating patients with breast cancer.

4-1BB Agonist Focuses CD8+ Tumor-Infiltrating T-Cell Growth into a Distinct Repertoire Capable of Tumor Recognition in Pancreatic Cancer

Purpose: Survival for pancreatic ductal adenocarcinoma (PDAC) patients is extremely poor and improved therapies are urgently needed. Tumor-infiltrating lymphocyte (TIL) adoptive cell therapy (ACT) has shown great promise in other tumor types, such as metastatic melanoma where overall response rates of 50% have been seen. Given this success and the evidence showing that T-cell presence positively correlates with overall survival in PDAC, we sought to enrich for CD8+ TILs capable of autologous tumor recognition. In addition, we explored the phenotype and T-cell receptor repertoire of the CD8+ TILs in the tumor microenvironment.Experimental Design: We used an agonistic 4-1BB mAb during the initial tumor fragment culture to provide 4-1BB costimulation and assessed changes in TIL growth, phenotype, repertoire, and antitumor function.Results: Increased CD8+ TIL growth from PDAC tumors was achieved with the aid of an agonistic 4-1BB mAb. Expanded TILs were characterized by an activated but not terminally differentiated phenotype. Moreover, 4-1BB stimulation expanded a more clonal and distinct CD8+ TIL repertoire than IL2 alone. TILs from both culture conditions displayed MHC class I-restricted recognition of autologous tumor targets.Conclusions: Costimulation with an anti-4-1BB mAb increases the feasibility of TIL therapy by producing greater numbers of these tumor-reactive T cells. These results suggest that TIL ACT for PDAC is a potential treatment avenue worth further investigation for a patient population in dire need of improved therapy. Clin Cancer Res; 23(23); 7263-75. ©2017 AACR.

Identification and Characterization of Neoantigens As Well As Respective Immune Responses in Cancer Patients

Cancer immunotherapy has recently emerged as a powerful tool for the treatment of diverse advanced malignancies. In particular, therapeutic application of immune checkpoint modulators, such as anti-CTLA4 or anti-PD-1/PD-L1 antibodies, have shown efficacy in a broad range of malignant diseases. Although pharmacodynamics of these immune modulators are complex, recent studies strongly support the notion that altered peptide ligands presented on tumor cells representing neoantigens may play an essential role in tumor rejection by T cells activated by anti-CTLA4 and anti-PD-1 antibodies. Neoantigens may have diverse sources as viral and mutated proteins. Moreover, posttranslational modifications and altered antigen processing may also contribute to the neoantigenic peptide ligand landscape. Different approaches of target identification are currently applied in combination with subsequent characterization of autologous and non-self T-cell responses against such neoantigens. Additional efforts are required to elucidate key characteristics and interdependences of neoantigens, immunodominance, respective T-cell responses, and the tumor microenvironment in order to define decisive determinants involved in effective T-cell-mediated tumor rejection. This review focuses on our current knowledge of identification and characterization of such neoantigens as well as respective T-cell responses. It closes with challenges to be addressed in future relevant for further improvement of immunotherapeutic strategies in malignant diseases.