Tumor-infiltrating Lymphocytes Cultures Research Articles

Concomitant Expression of CD39, CD69, and CD103 Identifies Antitumor CD8+ T Cells in Breast Cancer Implications for Adoptive Cell Therapy.

In cancer, an effective immune response involves the action of several different cell types, among which CD8 T cells play a major role as they can specifically recognize and kill cancer cells via the release of cytotoxic molecules and cytokines, being of major importance for adoptive cell transfer (ACT) of ex vivo expanded tumor-infiltrating lymphocytes (TILs). The inflammation resulting from the tumor growth attracts both activated and bystander T cells. For an effective antitumor response, the T cell must express a specific group of chemokine receptors and integrins which include CD103, CD39, CD69, and CD25. These markers had already been analyzed in various cancers, not including breast cancer and their subsequent subtypes, until now. To analyze, the key receptors on ex vivo expanded tumor-infiltrating lymphocytes in luminal A and luminal B breast cancer (BC) subtypes. We were successful in expanding TILs ex vivo using a standard TIL culture condition from a cohort study of 15 primary luminal A and luminal B breast cancer patients. Furthermore, we examined the expression of CD103, CD39, CD69, and CD25 biomarkers after the expansion by flow cytometry. We found that the information about the percentage of TILs obtainable after the ex vivo expansion is not associated to nor it is dependent on the heterogeneity of the TIL population before the expansion and does not differ by the molecular subtype (p>0.05). We also found that there is a major population of memory-resident antitumor CD8+CD103+CD39+ and CD8+CD103+ CD69+ TILs present in the stroma after the expansion when compared to CD4 immunosubtypes (p<0.0001). Only the CD8+CD103+CD39+ subpopulation was related to BC subtype (0.0009). Evidence from our study suggests that CD8 TILs present in the stroma of luminal A and luminal B breast cancer patients can be quantified and phenotyped by flow cytometry and be further expanded ex vivo. The immuno-phenotyping of these markers may be targeted to improve the success of immunotherapeutic approaches, such as adoptive cellular therapy (ACT) in patients with BC.

Tumor reactive T cells from the cerebrospinal fluid of patients with leptomeningeal disease from melanoma.

2027 Background: Leptomeningeal disease (LMD) is a devastating complication from cancer, with a median survival of 6-8 weeks. The incidence of LMD is highest in melanoma (5-25%) carrying the worst prognosis. Adoptive cell therapy (ACT) using tumor-infiltrating lymphocytes (TILs) showed complete and durable responses in patients with advanced metastatic melanoma. CSF-derived T cell populations in LMD shift to more exhausted phenotypes compared to extracranial and brain metastases. Ex vivo large T cell expansion can overcome this shortfall, with adoptive T cell transfer representing a novel therapeutic approach to treat melanoma LMD (M-LMD). The goal of this study is to optimize rapid CSF-derived tumor reactive T cell expansion in M-LMD, and evaluate the immune microenvironment in CSF compared to peripheral immunity and anti-tumoral response. Methods: CSF was collected from M-LMD patients (n=6) via lumbar puncture or Ommaya. Cells were plated following established TIL culture protocols to determine optimal expansion conditions i.e.: 1) 6000 IU/mL IL-2, 2) IL-2+OKT3, 3) IL-2+anti-4-1BB agonistic antibody, 4) IL-2+IL-7+IL-15+IL-21, 5) IL-2+anti-CD3/CD28 human dynabeads, &amp; 6) IL-2+anti-CD3/CD28/CD137 human dynabeads. After 4 weeks, T cells were propagated via rapid expansion protocol (REP) and phenotyped for CD4+ and CD8+ T cells with flow cytometry. T cells were co-cultured for 18-24 hours with HLA-matched melanoma cell lines to assess functionality, and IFN-y levels evaluated in supernatant. Ongoing studies are evaluating other biomarkers i.e., chemokines via Luminex. To examine the expanded TCR clonotypes, TCR beta seq was done in CSF-derived T cells at different times point of expansion and peripheral T cells. Results: Collected CSF yielded an average 8.12e4 viable cells for expansion (range 5e2-2.43e6). After initial culture in IL-2, 61.9% of samples showed increased cell yield with an average 101.68-fold expansion (range 2.35-1054). PreREP T cells were predominantly CD4+ (45.7%). REP was completed with a 100% success rate (mean 187.47-fold expansion). Post-REP flow cytometry analysis revealed similar results with further expansion of T cells. Additional culture supplements (Methods #2-6) produced similar expansion with a reduced T cell input requirement and demonstrated the potential to enrich for CD8+ T cells. M-LMD T cells were highly functional, producing substantial levels of IFN-y in response to HLA-matched melanoma cell lines. Anti-CD3/CD28 produced a larger expansion of T cells with higher levels of IFN-y. Preliminary TCR beta sequencing data revealed a distinct clonal distribution between peripheral and CSF-derived T cells. Conclusions: Therapies for LMD patients are desperately needed. Results demonstrate successful expansion of T cells ex vivo from CSF in M-LMD. Results raise potential to use autologous CSF-derived T cells as therapeutic strategy for patients with LMD.

Abstract 4240: A comprehensive in vitro tumor model: One-stop simultaneous isolation and culture of tumoroids, CAFs and TILs for advancing immuno-oncology research

Abstract The tumor microenvironment (TME), composed of a diverse array of cells, jointly participates in tumor formation and has attracted attention as a direct or indirect therapeutic target. Among the tumor-forming cells, cancer cells, cancer-associated fibroblast (CAF), and tumor-infiltrating lymphocytes (TILs) comprise major proportion and players in tumor biology. Therefore, an in vitro tumor model composed of at least above three major cellular players better mimics a patient’s tumor. Here, we developed a patient-derived tumor model containing tumoroids, CAFs and TILs isolated from the patient’s tumor tissue by using one-stop isolation culture system. Our one-stop culture system utilizes a Transwell-based method that concurrently segregates cancer cells, CAFs, and TILs based on distinct characteristics such as cell size, migration speed, and growth. Lung tumoroids, fibroblasts, and TILs segregated in Matrigel-coated upper Transwell chamber, Transwell pores and in the lower chamber, respectively. Lung tumoroids maintain the patient’s lung cancer tissue characteristics and genetic features during extended in vitro cultivation. Fibroblasts extracted from the Transwell pores exhibit significant similarity to CAFs found in patient tissue. TILs in the lower part of the Transwell chamber closely resemble those found in the original cancer tissue analyzed by FACS. We have also refined the functionality of TILs through a two-week expansion process. Patients’ tumor composed of 0.15 to 95.3 % of EpCAM positive tumor cells, 0.14 to 19.4 % of CD90 positive fibroblasts and 3.98 to 91.2 % of immune cells in FACS analysis. By reassembling three main cellular components of the tumor in a proper proportion, we developed a co-culture platform for a patient-derived tumor model reproducing patient-specific TME conditions. The co-culture platform showed a potential not only for an experimental model but also to use a predictive test of personalized immunotherapy responses for lung cancer patients. Citation Format: YOO RI KO, Sung Min Kim, Hye Seon Park, Se Jin Jang. A comprehensive in vitro tumor model: One-stop simultaneous isolation and culture of tumoroids, CAFs and TILs for advancing immuno-oncology research [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4240.

Core Needle Biopsies as an Alternative Source for Ex Vivo Expanded TIL for Adoptive Cell Therapy in Triple-Negative Breast Cancer.

Adoptive transfer of ex vivo expanded tumor-infiltrating lymphocytes (TILs) have produced long-term response in metastatic cancers. TILs have traditionally been expanded from surgically resected specimens. Ultrasound-guided core needle biopsy (CNB) is an alternative method that avoids the morbidity of surgery and have added benefits which may include patients not amenable to surgery as well as the potential to produce TILs from multiple lesions in the same patient. We assessed the ability to produce and expand TILs from primary triple-negative breast cancer tumors from CNB (n=7) and demonstrate comparable expansion, phenotype and cytokine secretion after phorbol myristate acetate-ionomycin stimulation to TILs expanded from surgery (n=6). T cell Receptor clonality and diversity were also comparable between the two cohorts throughout the TIL culture. CNB is a safe and feasible method to obtain tumor tissue for TIL generation in patients with triple-negative breast cancer.

P06.04.B NEW APPROACHES FOR EXPANDING GLIOBLASTOMA INFILTRATING LYMPHOCYTES

Abstract BACKGROUND Adoptive cell therapy using tumor infiltrating lymphocytes (TILs) has shown promise in melanoma and Non-Small Cell Lung Cancer. TILs culture and expansion from GBM remains challenging due to paucity of infiltrated T-cells that are also exhausted. This hinders creation of potent TILs. We have developed a new efficient method to manufacture potent TILs from GBM samples. METHODS We have developed efficient TILs manufacturing methods using both solid and aspirated liquid samples collected during vacuum assisted excision containing tumor fragments that may stem predominantly from the tumor margins and provide a source for TILs. We followed the traditional two steps: initial expansion (preREP) where T-cells are expanded with tumor cells to selectively expand tumor antigen-reactive TILs, followed by a large-scale expansion (REP) after further activation. For both steps we optimized media and reagents. RESULTS TILs cultures from solid tumors were established from enzymatically digested tissue and by fragment plating. Successful TILs yield from liquid samples required enzymatic digestion, debris removal and RBC lysis prior to culture initiation. PreREP TILs yields ranged from a few million to 2 billion viable cells for solid and liquid samples. REP of TILs from liquid samples expanded similarly from solid samples. REP of TILs reached up to 556-fold expansion (mean: 346, range: 95-556) providing promising numbers of activated TILs. The potency of the TILs was demonstrated with tumor specific Interferon-gamma production when cultured with matched tumor digest or neurospheres. CONCLUSIONS We successfully expanded TILs that are rich in cytotoxic T-cells, demonstrated their tumor reactivity and further expanded the preREP TILs to reach therapeutic doses. We have characterized the TILs by scRNA and TCRseq and analyze paired TCR reads using scRNA sequencing. Overrepresented TCR alpha and beta chains will be linked by a P2A site and will be cloned into a lentiviral vector to establish a TCR library which will be transduced into novel Jurkat Triple Parameter Reporter Cell Lines under the control of different T cell activation programs. TCR Jurkat Libraries will be cocultured with original tumor material and sorted to identify tumor reactive TCRs; enabling us to define the percentage of TCRs that are enriched by TIL isolation that are specifically reactive to tumor vs bystander expanded TCR cells. Ultimately, we aim to bring this therapy to patients in a clinical trial.

"One more chance to survive": the experiences of patients with advanced melanoma and their partners with tumor-infiltrating lymphocyte therapy-a qualitative study and recommendations for future care.

Patients with advanced melanoma refractory to first-line treatment have a need for effective second-line treatment options. A recent phase 3 trial showed promising results for adoptive cell therapy with tumor-infiltrating lymphocytes (TILs) as second-line therapy in patients with advanced melanoma. However, it remains unknown how patients and their partners experience TIL therapy, which is key to evaluate and improve the quality of care. Semi-structured interviews about the experience of TIL therapy were conducted with patients with advanced melanoma and their partners 2-4 weeks post-treatment (short term) and >6 months after treatment (long term). In total, 25 interviews were conducted with advanced melanoma patients treated with TIL (n=13) and their partners (n=12), with the majority being short-term interviews (n=17). Overall, patients and partners experienced TIL therapy as intense (uncertainty of successful TIL culture, multiple treatment-related toxicities, and extensive hospitalization). Patients and partners with young children or other caregiving responsibilities encountered the most challenges during TIL therapy. All patients, however, reported a recovery of all treatment-related toxicities within 2-4 weeks (except fatigue). Clinical data justify the role of TIL therapy in the treatment of advanced melanoma. With the distinct nature of TIL therapy compared to the current standard of care, we have provided patient-centered recommendations that will further enhance the quality of TIL therapy. As more patients with advanced melanoma are expected to receive TIL therapy in the future, our findings could be incorporated into survivorship care plans for this novel group of advanced melanoma survivors treated with TIL.

Tumor-infiltrating CD36+CD8+T cells determine exhausted tumor microenvironment and correlate with inferior response to chemotherapy in non-small cell lung cancer

BackgroundThe scavenger receptor CD36 was reported to be highly expressed on tumor-infiltrating CD8+ T cells, but the clinical role remains obscure. This study aims to explore the infiltration and clinical value of CD36+CD8+ T cells in NSCLC.MethodsImmunohistochemistry and immunofluorescence were conducted for survival analyses and immunological evaluation in 232 NSCLC patients in Zhongshan Hospital. Flow cytometry analyses were carried out to assess the immune cells from fresh tumor samples, non-tumor tissues and peripheral blood. In vitro tumor infiltrating lymphocytes cultures were conducted to test the effect of CD36 blockage.ResultsAccumulation of CD36+CD8+ T cells in tumor tissues was correlated with more advanced stage (p < 0.001), larger tumor size (p < 0.01), and lymph node metastasis (p < 0.0001) in NSCLC. Moreover, high infiltration of CD36+CD8+ T cells indicated poor prognosis in terms of both overall survival (OS) and recurrence-free survival (RFS) and inferior chemotherapy response. CD36+CD8+ T cells showed decreased GZMB (p < 0.0001) and IFN-γ (p < 0.001) with elevated PD-1 (p < 0.0001) and TIGIT (p < 0.0001). Analysis of tumor-infiltrating immune cell landscape revealed a positive correlation between CD36+CD8+ T cells and Tregs (p < 0.01) and M2-polarized macrophages (p < 0.01) but a negative correlation with Th1 (p < 0.05). Notably, inhibition of CD36 partially restored the cytotoxic function of CD8+ T cells by producing more GZMB and IFN-γ.ConclusionCD36+CD8+ T cells exhibit impaired immune function and high infiltration of CD36+CD8+ T cells indicated poor prognosis and inferior chemotherapy response in NSCLC patients. CD36 could be a therapeutic target in combination with chemotherapy in NSCLC patients.

Modulating the proliferative and cytotoxic properties of patient-derived TIL by a synthetic immune niche of immobilized CCL21 and ICAM1.

A major challenge in developing an effective adoptive cancer immunotherapy is the ex-vivo generation of tumor-reactive cells in sufficient numbers and with enhanced cytotoxic potential. It was recently demonstrated that culturing of activated murine CD8+ T-cells on a "Synthetic Immune Niche" (SIN), consisting of immobilized CCL21 and ICAM-1, enhances T-cell expansion, increases their cytotoxicity against cultured cancer cells and suppresses tumor growth in vivo. In the study reported here, we have tested the effect of the CCL21+ICAM1 SIN, on the expansion and cytotoxic phenotype of Tumor Infiltrating Lymphocytes (TIL) from melanoma patients, following activation with immobilized anti-CD3/CD28 stimulation, or commercial activation beads. The majority of TIL tested, displayed higher expansion when cultured on the coated SIN compared to cells incubated on uncoated substrate and a lower frequency of TIM-3+CD8+ cells after stimulation with anti-CD3/CD28 beads. Comparable enhancement of TIL proliferation was obtained by the CCL21+ICAM1 SIN, in a clinical setting that included a 14-day rapid expansion procedure (REP). Co-incubation of post-REP TIL with matching target cancerous cells demonstrated increased IFNγ secretion beyond baseline in most of the TIL cultures, as well as a significant increase in granzyme B levels following activation on SIN. The SIN did not significantly alter the relative frequency of CD8/CD4 populations, as well as the expression of CD28, CD25, several exhaustion markers and the differentiation status of the expanded cells. These results demonstrate the potential capacity of the CCL21+ICAM1 SIN to reinforce TIL-based immunotherapy for cancer patients.

MRNAs encoding IL-12 and a decoy-resistant variant of IL-18 synergize to engineer T cells for efficacious intratumoral adoptive immunotherapy

Interleukin-12 (IL-12) gene transfer enhances the therapeutic potency of adoptive Tcell therapies. We previously reported that transient engineering of tumor-specific CD8 Tcells with IL-12 mRNA enhanced their systemic therapeutic efficacy when delivered intratumorally. Here, we mix Tcells engineered with mRNAs to express either single-chain IL-12 (scIL-12) or an IL-18 decoy-resistant variant (DRIL18) that is not functionally hampered by IL-18 binding protein (IL-18BP). These mRNA-engineered Tcell mixtures are repeatedly injected into mouse tumors. Pmel-1 Tcell receptor (TCR)-transgenic Tcells electroporated with scIL-12 or DRIL18 mRNAs exert powerful therapeutic effects in local and distant melanoma lesions. These effects are associated with Tcell metabolic fitness, enhanced miR-155 control on immunosuppressive target genes, enhanced expression of various cytokines, and changes in the glycosylation profile of surface proteins, enabling adhesiveness to E-selectin. Efficacy of this intratumoral immunotherapeutic strategy is recapitulated in cultures of tumor-infiltrating lymphocytes (TILs) and chimeric antigen receptor (CAR) Tcells on IL-12 and DRIL18 mRNA electroporation.

Expansion of KRAS hotspot mutations reactive T cells from human pancreatic tumors using autologous T cells as the antigen-presenting cells.

Adoptive cell therapy (ACT) with expanded tumor-infiltrating lymphocytes (TIL) or TCR gene-modified T cells (TCR-T) that recognize mutant KRAS neo-antigens can mediate tumor regression in patients with advanced pancreatic ductal adenocarcinoma (PDAC) (Tran et al in N Engl J Med, 375:2255-2262, 2016; Leidner et al in N Engl J Med, 386:2112-2119, 2022). The mutant KRAS-targeted ACT holds great potential to achieve durable clinical responses for PDAC, which has had no meaningful improvement over 40years. However, the wide application of mutant KRAS-centric ACT is currently limited by the rarity of TIL that recognize the mutant KRAS. In addition, PDAC is generally recognized as a poorly immunogenic tumor, and TILs in PDAC are less abundant than in immunogenic tumors such as melanoma. To increase the success rate of TIL production, we adopted a well-utilized K562-based artificial APC (aAPC) that expresses 4-1BBL as the costimulatory molecules to enhance the TIL production from PDCA. However, stimulation with K562-based aAPC led to a rapid loss of specificity to mutant KRAS. To selectively expand neo-antigen-specific T cells, particularly mKRAS, from the TILs, we used tandem mini gene-modified autologous T cells (TMG-T) as the novel aAPC. Using this modified IVS protocol, we successfully generated TIL cultures specifically reactive to mKRAS (G12V). We believe that autologous TMG-T cells provide a reliable source of autologous APC to expand a rare population of neoantigen-specific T cells in TILs.

Why do tumor-infiltrating lymphocytes have variable efficacy in the treatment of solid tumors?

Lymphocytes in tumor tissue are called tumor-infiltrating lymphocytes (TILs), and they play a key role in the control and treatment of tumor diseases. Since the discovery in 1987 that cultured TILs can kill tumor cells more than 100 times more effectively than T-cells cultured from peripheral blood in melanoma, it has been confirmed that cultured TILs can successfully cure clinical patients with melanoma. Since 1989, after we investigated TIL isolation performance from solid tumors, we modified some procedures to increase efficacy, and thus successfully established new TIL isolation and culture methods in 1994. Moreover, our laboratory and clinicians using our cultured TILs have published more than 30 papers. To improve the efficacy of TILs, we have been carrying out studies of TIL efficacy to treat solid tumor diseases for approximately 30 years. The three main questions of TIL study have been "How do TILs remain silent in solid tumor tissue?", "How do TILs attack homologous and heterologous antigens from tumor cells of solid tumors?", and "How do TILs infiltrate solid tumor tissue from a distance into tumor sites to kill tumor cells?". Research on these three issues has increasingly answered these questions. In this review I summarize the main issues surrounding TILs in treating solid tumors. This review aims to study the killing function of TILs from solid tumor tissues, thereby ultimately introducing the optimal strategy for patients suffering from solid tumors through personalized immunotherapy in the near future.

Abstract 5609: Investigating the undifferentiated pleomorphic sarcoma microenvironment through cytokine profiles of primary tumor and immune infiltrates

Abstract Sarcoma is a heterogeneous group of connective tissue cancers with over 60 subtypes. Curative treatment relies on surgical resection combined with radiation. In the event of metastasis, chemotherapy is used but generally only with palliative intent. Given the heterogeneity of sarcomas, targeted therapies are limited, which has contributed to the relatively stagnant survival rates seen in the past decades. Objective: Personalized treatments, such as adoptive cell therapy (ACT), may be promising for select sarcoma patients, specifically those with Undifferentiated Pleomorphic Sarcoma (UPS). To better understand ACT’s feasibility for UPS, we aim to investigate the intersection of tumor-infiltrating lymphocytes (TILs) and tumor cells by examining their cytokine output, whose role remains largely unstudied. Methods: Tissue samples from untreated sarcoma patients have been collected and viably preserved by our group. The samples were processed for in vitro expansion of tumor or TIL cell lines. Tumor cultures were validated with Whole Exome Sequencing (WES) to ensure tumor-specific variations were retained. TILs were isolated with tumor fragment (TF) processing and magnetic bead coated anti-CD3/CD28 Rapid Expansion Protocol (REP). After validating tumor cultures, both tumor and TIL-secreted cytokines were evaluated using Luminex assays. Results: Of the 11 primary UPS samples cultured, 10 generated viable cell cultures as defined by the presentation of stable growth beyond passage 5. A total of 3 cell lines were selected for further validation, and through WES, retained tumor specific variations beyond passage 5. On the other hand, the sarcoma-optimized TF and REP protocols expanded TILs from 7 of 8 UPS cases and yielded up to 6 x 10^7 cells. Although IL-2 is commonly used to facilitate TIL growth, it can also cause activation-induced cell death which is problematic for therapy. We demonstrated that an alternative γ-chain interleukin, IL-15, can support UPS TIL growth comparable to IL-2. Unbiased cytokine screening detected anti-tumoral CXCL9/IFN-γ and pro-tumoral IL-10/TGF-Beta as highly secreted by TIL cultures while some tumor cultures secreted relatively high concentrations of IL-6 and CCL2. Conclusion: We developed a robust in vitro pipeline to expand sarcoma tumor cultures and TILs for downstream characterization. Functional assays aimed at dissecting the consequences of tumor-mediated IL-6 secretion are underway. These include siRNA-induced knock downs of genes hypothesized to augment the cytokine profile of tumor cells. Future evaluation of TILs will identify their clinical efficacy via flow cytometry and intracellular cytokine staining. Understanding cytokine secretion from both the tumor and immune components of sarcoma will aid in elucidating interactions within the microenvironment that may be therapeutically relevant. Citation Format: Victoria Coward, Jacky Chen, Nalan Gokgoz, Kim Tsoi, Jay S. Wunder, Irene L. Andrulis. Investigating the undifferentiated pleomorphic sarcoma microenvironment through cytokine profiles of primary tumor and immune infiltrates [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5609.

Tumor-Infiltrating T Cells Can Be ExpandedSuccessfully from Primary Uveal Melanoma after Separation from Their TumorEnvironment.

PurposeTo evaluate whether expanded tumor-infiltrating lymphocytes (TILs) can be obtained from primary uveal melanoma (UM) for potential use as adjuvant treatment in patients at risk of developing metastatic disease.DesignExperimental research study.ParticipantsFreshly obtained primary UM from 30 patients.MethodsThree different methods were used to expand TILs: (1) direct culture from small fragments of fresh tumor tissue, (2) single-cell tissue preparation by enzymatic digestion and subsequent enrichment of mononuclear cells, and (3) selection of CD3+ T cells using magnetic beads. Surface expression of costimulatory and inhibitory T-cell markers and T-cell reactivity against autologous tumor cells was assessed. Clinical, histopathologic, genetic, and immunologic characteristics of the tumors were compared with the capacity to expand TILs and with their reactivity against autologous tumor cells.Main Outcome MeasuresThe feasibility of expanding TILs from primary UM, testing their reactivity to autologous UM cells, and evaluating the impact of an immunomodulatory environment.ResultsDirect culture of tumor parts led to successful TIL culture in 4 of 22 tumors (18%), enrichment of mononuclear cells gave rise to TILs in 5 of 12 tumors (42%), while preselection of CD3+ T cells with magnetic beads resulted in TIL expansion in 17 of 25 tumors (68%). In 8 of 17 tumors (47%), the TIL cultures comprised UM-reactive T cells. The presence of UM-reactive T cells among TILs was not related to clinical, histologic, genetic, or immunological tumor characteristics. Interestingly, RNA-Seq analysis showed that approximately half of the UM tumors displayed an increased expression of immunomodulatory molecules related to T-cell suppression, such as galectin 3, programmed death-ligand 1, cytotoxic T-lymphocyte-associated protein 4, indoleamine 2,3-dioxygenase 1, and lymphocyte activating 3, potentially explaining why T cells require optimal removal of tumor components for expansion.ConclusionsThe need to separate TILs from their tumor microenvironment for their successful expansion and the presence of UM-reactive T cells among TILs suggests that these UM-reactive T cells are strongly suppressed in vivo and that UM is immunogenic. These findings indicate that adoptive TIL therapy could be an option as an adjuvant treatment in primary UM patients at high risk of developing metastatic disease.

Impact of HPV status on immune responses in head and neck squamous cell carcinoma

The main objective of our study was to understand the impact of immune cell composition and the tumor-reactivity of tumor infiltrating lymphocytes (TIL) in HPV-positive (HPV+) and HPV-negative (HPV-) head and neck squamous cell carcinoma (HNSCC). TIL cultures were established from primary HNSCC tumors, the T cell subsets were phenotypically characterized using flow cytometry, and Interferon (IFN)-γ ELISA assay was used to determine TIL function. NanoString Immune Profiler was used to determine an immune signature by HPV-status, and multiplex immunohistochemistry (MIHC) was used to quantify immune cell distributions and their spatial relationships. Results showed that HPV+ and HPV- HNSCC had similar capacity to expand IFN-γ reactive TIL populations, and these TIL populations had similar characteristics. NanoString analysis revealed increased differential expression of genes related to B cell functions in HPV+ HNSCC, which were significant at a Benjamini-Yekutieli adjusted p-value of < 0.001. MIHC also displayed increased CD8+ T cell and CD19/CD20+ B cell densities in the tumor region of HPV+ HNSCC as opposed to HPV- HNSCC (p < 0.01). Increases in a combined metric of tumor B cell content and stromal plasma cell content was associated with increased progression-free survival in HPV- HNSCC patients treated with immune checkpoint inhibitor therapy (p = 0.03). In summary, TIL populations expanded from HPV+ and HPV- HNSCC displayed similar IFN-γ reactivity. However, we identified a strong B-cell signature present within HPV+ HNSCC, and higher B and plasma cell content associated with improved PFS in HPV- HNSCC patients treated with immune checkpoint inhibitors.

Investigating the Potential of Isolating and Expanding Tumour-Infiltrating Lymphocytes from Adult Sarcoma.

Simple SummarySarcomas are rare cancers that arise from connective tissue. There are more than 50 subtypes, many of which are associated with a high risk of metastasis and poor prognosis. Subtype-specific treatment is limited and conventional treatment for advanced disease has varying effects across individuals and tumour subtypes. Adoptive cell therapy shows potential to provide more personalized treatment; this study aims to explore the potential of using tumour-infiltrating lymphocytes (TIL) to treat sarcoma. We optimized a sarcoma-specific expansion protocol and successfully expanded TILs from 54 of 92 sarcoma specimens. We characterized primarily CD4+ and CD8+ T-cells in the expanded TIL cultures and demonstrated their reactivity to general stimuli. Although sarcomas in general do not have abundant lymphocytic infiltration, our expansion protocol allowed for successful expansions of viable and reactive lymphocytes, thus showing the prospects of adopting TIL therapy in sarcoma.Sarcomas are a heterogeneous group of mesenchymal neoplasms, many of which are associated with a high risk of metastasis and poor prognosis. Conventional chemotherapy and targeted therapies have varying effects across individuals and tumour subtypes. The current therapies frequently provide limited clinical benefit; hence, more effective treatments are urgently needed. Recent advances in immunotherapy, such as checkpoint inhibition or adoptive cell therapy (ACT), show potential in increasing efficacy by providing a more personalized treatment. Therapy with tumour-infiltrating lymphocytes (TILs) is an emerging field in immunotherapy. Here, we collected 190 sarcoma tumour specimens from patients without pre-operative adjuvant treatment in order to isolate TILs. We compared different methods of TIL expansion and optimized a protocol specifically for efficacy in culturing TILs from sarcoma. The expanded TIL populations were characterized by flow cytometry analysis using CD3, CD4, CD8, CD14, CD19 and CD56 markers. The TIL populations were non-specifically stimulated to establish TIL reactivity. Through an optimized expansion protocol, TILs were isolated and cultured from 54 of 92 primary sarcoma specimens. The isolated TILs varied in CD4+ and CD8+ T-cell compositions and retained their ability to release IFNγ upon stimulation. Our results suggest that certain sarcoma subtypes have the potential to yield a sufficient number of TILs for TIL therapy.

Genetics and Therapeutic Responses to Tumor-Infiltrating Lymphocyte Therapy of Pancreatic Cancer Patient-Derived Xenograft Models.

Pancreatic cancer is the seventh leading cause of cancer-related deaths worldwide. Checkpoint immunotherapy has not yet shown encouraging results in pancreatic cancer possibly because of a poor immunogenicity and/or an immune suppressive microenvironment. The aim of this study was to develop patient-derived xenograft (PDX) models, compare their genetics to the original biopsies, and assess if autologous tumor-infiltrating lymphocytes (TILs) would have antitumoral activity in pancreatic cancer. We subcutaneously transplanted tumors from 29 patients into NOG mice to generate PDX models. We established TIL cultures and injected them into PDX mice. We analyzed histology and genetics of biopsies and PDX tumors. Tumor growths were confirmed in 11 of 29 transplantations. The PDX tumors histologically resembled their original biopsies, but because stromal cells in the PDX model tumors were from mouse, their gene expression differed from the original biopsies. Immune checkpoint ligands other than programmed death ligand-1 (PD-L1) were expressed in pancreatic cancers, but PD-L1 was rarely expressed. When it was expressed, it correlated with tumor take in PDX models. One of the 3 tumors that expressed PD-L1 was an adenosquamous cancer, and another had a mismatch repair deficiency. TILs were expanded from 6 tumors and were injected into NOG or human interleukin-2 transgenic-NOG mice carrying PDX tumors. Regression of tumors could be verified in human interleukin-2 transgenic-NOG mice in 3 of the 6 PDX models treated with autologous TILs, including the adenosquamous PDX model. PDX models of pancreatic cancer can be used to learn more about tumor characteristics and biomarkers and to evaluate responses to adoptive cell therapy and combination therapies. The major benefit of the model is that modifications of T cells can be tested in an autologous humanized mouse model to gain preclinical data to support the initiation of a clinical trial.

64 A cloning and expression system of the neoantigen-specific TCRs from tumor-infiltrating lymphocytes by single-cell sequencing of paired TCRα and TCRβ chains

BackgroundT-cells that target tumor neoantigens arising from cancer mutations are the primary mediators of cancer immunotherapies. Identifying neoantigens and T-cells that recognize them is essential for T-cell-based immunotherapy. However, neoantigen-reactive Tumor-infiltrating lymphocytes (TILs) are highly differentiated or exhausted with a limited proliferative capacity; it is challenging to expand them for a sufficient number to probe their specificity. Therefore, we developed a novel cloning and expression system to examine TCRs discovered by single-cell sequencing of TILs for their neoantigen-specificity.MethodsTILs of lung cancer and sarcoma were analyzed. Surgically removed tumors were divided into several pieces. They were enzymatically digested to prepare fresh tumor digest (FTD) and cryopreserved. They were used to generate TIL cultures and perform WES and RNA-Seq to identify tumor-specific mutations. MHCflurry was used to predict the binding affinity of potential epitopes arising from these mutations to HLA class I. Peptides that were predicted to bind to patients‘ own MHC class I molecules strongly were then synthesized. Single TILs isolated with the ICELL8® cx system (Takara Bio) were dispensed into a nanowell TCR chip containing preprinted barcodes. Barcoded cDNAs were PCR-amplified in-chip, pooled off-chip, and used as a template in the TCR-specific PCR or for the whole transcriptome library generation of 5’ ends of all transcripts. Based on single-cell transcriptome data and TCR profiles of TILs, we predict and prioritize neoantigen-specific TCRs and cloned them into siTCR® retrovirus vectors. These TCRs were transduced into SUP-T1-based reporter cells in which ZsGreen fluorescent protein expression is controlled by AP-1 and NFAT binding sites. TCR-expressing reporter cells were cocultured with patient autologous APCs pulsed with a pool of candidate neoantigen peptides. ZsGreen expression indicates that TCRs match their cognate neoantigens.ResultsIn a lung cancer patient, we set up 18 TIL cultures and obtained 12 TILs. TILs were cocultured with FTD; IFN-γ production was measured by ELISA to evaluate their reactivity to the autologous tumor. NGS identified 197 somatic mutations, 4 fusion genes, and 8 highly expressed cancer-testis antigens. Among them, 339 candidate peptides were synthesized and screened. In addition, we cloned 3 pairs of TCRαβ chains from most expanded TIL cultures and 4 TCRs from ex vivo TILs with exhausted phenotype. Two reporter cells that express TCRs from exhausted TILs responded to the same neoantigen peptide.ConclusionsGenerating TCR expressing cell lines facilitated the identifying neoantigens and their cognate TCR sequences from patients.Ethics ApprovalG3545

Randomized phase II trial of lymphodepletion plus adoptive cell transfer of tumor-infiltrating lymphocytes, with or without dendritic cell vaccination, in patients with metastatic melanoma

BackgroundThe adoptive transfer of tumor-infiltrating lymphocytes (TIL) has demonstrated robust efficacy in metastatic melanoma patients. Tumor antigen–loaded dendritic cells (DCs) are believed to optimally activate antigen-specific T lymphocytes. We hypothesized...

Expanded Tumor-infiltrating Lymphocytes From Soft Tissue Sarcoma Have Tumor-specific Function.

Adoptive cell transfer (ACT) with tumor-infiltrating lymphocytes (TILs) can generate durable clinical responses in patients with metastatic melanoma and ongoing trials are evaluating efficacy in other advanced solid tumors. The aim of this study was to develop methods for the expansion of tumor-reactive TIL from resected soft tissue sarcoma to a degree required for the ACT. From 2015 to 2018, 70 patients were consented to an institutional review board-approved protocol, and fresh surgical specimens were taken directly from the operating room to the laboratory. Fragments of the tumor (1 mm3) or fresh tumor digest were placed in culture for a period of 4 weeks. Successfully propagated TIL from these cultures were collected and analyzed by flow cytometry. TIL were cocultured with autologous tumor and function was assessed by measurement of interferon-γ in the supernatant by enzyme-linked immunosorbent assay. Initial TIL cultures were further expanded using a rapid expansion protocol. Nearly all specimens generated an initial TIL culture (91% fragment method, 100% digest method). The phenotype of the TIL indicated a predominant CD3+ population after culture (43% fragment, 52% digest) and TIL were responsive to the autologous tumor (56% fragment, 40% digest). The cultured TIL expanded to a degree required for clinical use following rapid expansion protocol (median: 490-fold fragment, 403-fold digest). The data demonstrate the feasibility of TIL culture from fresh soft tissue sarcoma. The derived TIL have tumor-specific reactivity and can be expanded to clinically relevant numbers. An active ACT clinical trial using the methods described in this report is now approved for patients with metastatic soft tissue sarcoma.

Generation of neoantigen-specific T cells for adoptive cell transfer for treating head and neck squamous cell carcinoma

ABSTRACT Adoptive cell therapy using TCR-engineered T cells (TCR-T cells) represents a promising strategy for treating relapsed and metastatic cancers. We previously established methods to identify neoantigen-specific TCRs based on patients’ PBMCs. However, in clinical practice isolation of PBMCs from advanced-stage cancer patients proves to be difficult. In this study, we substituted blood-derived T cells for tumor-infiltrating lymphocytes (TILs) and used an HLA-matched cell line of antigen-presenting cells (APCs) to replace autologous dendritic cells. Somatic mutations were determined in head and neck squamous cell carcinoma resected from two patients. HLA-A*02:01-restricted neoantigen libraries were constructed and transferred into HLA-matched APCs for stimulation of patient TILs. TCRs were isolated from reactive TIL cultures and functionality was tested using TCR- T cells in vitro and in vivo. To exemplify the screening approach, we identified the targeted neoantigen leading to recognition of the minigene construct that stimulated the strongest TIL response. Neoantigen peptides were used to load MHC-tetramers for T cell isolation and a TCR was identified targeting the KIAA1429D1358E mutation. TCR-T cells were activated, exhibited cytotoxicity, and secreted cytokines in a dose-dependent manner, and only when stimulated with the mutant peptide. Furthermore, comparable to a neoantigen-specific TCR that was isolated from the patient’s PBMCs, KIAA1429D1358E-specific TCR T cells destroyed human tumors in mice. The established protocol provides the required flexibility to methods striving to identify neoantigen-specific TCRs. By using an MHC-matched APC cell line and neoantigen-encoding minigene libraries, autologous TILs can be stimulated and screened when patient PBMCs and/or tumor material are not available anymore. Abbreviations: Head and neck squamous cell carcinoma (HNSCC); adoptive T cell therapy (ACT); T cell receptor (TCR); tumor-infiltrating lymphocytes (TIL); cytotoxic T lymphocyte (CTL); peripheral blood mononuclear cell (PBMC); dendritic cell (DC); antigen-presenting cells (APC)