Infusion of Melan-A/Mart-1 specific tumor-infiltrating lymphocytes enhanced relapse-free survival of melanoma patients

Generation of Pure Highly Functional Human Anti-Tumor Specific Cytotoxic T Lymphocytes With Stem Cell-Like Memory Features for Melanoma Immunotherapy

Adoptive immunotherapy based on the transfer of anti-tumor cytotoxic T lymphocytes (CTLs) is a promising strategy to cure cancers. However, rapid expansion of numerous highly functional CTLs with long-lived features remains a challenge. Here, we constructed NIH/3T3 mouse fibroblast-based artificial antigen presenting cells (AAPCs) and precisely evaluated their ability to circumvent this difficulty. These AAPCs stably express the essential molecules involved in CTL activation in the HLA-A*0201 context and an immunogenic HLA-A*0201 restricted analogue peptide derived from MART-1, an auto-antigen overexpressed in melanoma. Using these AAPCs and pentamer-based magnetic bead-sorting, we defined, in a preclinical setting, the optimal conditions to expand pure MART-1-specific CTLs. Numerous highly purified MART-1-specific CTLs were rapidly obtained from healthy donors and melanoma patients. Both TCR repertoire and CDR3 sequence analyses revealed that MART-1-specific CTL responses were similar to those reported in the literature and obtained with autologous or allogeneic presenting cells. These MART-1-specific CTLs were highly cytotoxic against HLA-A*0201⁺ MART-1⁺ tumor cells. Moreover, they harbored a suitable phenotype for immunotherapy, with effector memory, central memory and, most importantly, stem cell-like memory T cell features. Notably, the cells harboring stem cell-like memory phenotype features were capable of self-renewal and of differentiation into potent effector anti-tumor T cells. These "off-the-shelf" AAPCs represent a unique tool to rapidly and easily expand large numbers of long-lived highly functional pure specific CTLs with stem cell-like memory T cell properties, for the development of efficient adoptive immunotherapy strategies against cancers.

Phase I/II clinical trial of adoptive cell transfer of sorted specific T cells for metastatic melanoma patients

Adoptive cell transfer (ACT) of tumor-specific T lymphocytes represents a relevant therapeutic strategy to treat metastatic melanoma patients. Ideal T-cells should combine tumor specificity and reactivity with survival in vivo, while avoiding autoimmune side effects. Here we report results from a Phase I/II clinical trial (NCT02424916, performed between 2015 and 2018) in which 6 metastatic HLA-A2 melanoma patients received autologous antigen-specific T-cells produced from PBMC, after peptide stimulation in vitro, followed by sorting with HLA-peptide multimers and amplification. Each patient received a combination of Melan-A and MELOE-1 polyclonal specific T-cells, whose specificity and anti-tumor reactivity were checked prior to injection, with subcutaneous IL-2. Transferred T-cells were also characterized in terms of functional avidity, diversity and phenotype and their blood persistence was evaluated. An increase in specific T-cells was detected in the blood of all patients at day 1 and progressively disappeared from day 7 onwards. No serious adverse events occurred after this ACT. Clinically, five patients progressed and one patient experienced a partial response following therapy. Melan-A and MELOE-1 specific T-cells infused to this patient were diverse, of high avidity, with a high proportion of T lymphocytes co-expressing PD-1 and TIGIT but few other exhaustion markers. In conclusion, we demonstrated the feasibility and safety of ACT with multimer-sorted Melan-A and MELOE-1 specific T cells to metastatic melanoma patients. The clinical efficacy of such therapeutic strategy could be further enhanced by the selection of highly reactive T-cells, based on PD-1 and TIGIT co-expression, and a combination with ICI, such as anti-PD-1.

Tumor infiltrating lymphocytes as adjuvant treatment in stage III melanoma patients with only one invaded lymph node after complete resection: results from a multicentre, randomized clinical phase III trial

BACKGROUND

Adoptive tumor-infiltrating lymphocytes (TIL) therapy and interleukin-2 (IL-2) have been investigated in melanoma.

AIM

To confirm previously observed preventive effects of TIL + IL2 in a subgroup of patients with relapsing metastatic stage III melanoma.

METHODOLOGY

Open-label, randomized two-group, multicenter five-year trial in adult stage III melanoma patients with only one invaded lymph node after complete resection. Patients received TIL + IL2 or abstention. TIL + IL2 was administered within 8 weeks after lymph node resection and 4 weeks after. Disease-free survival was assessed every 2 months up to month 18, every 3 months up to month 36 and every 4 months up to 5 years. A once-a-year follow-up was scheduled beyond the five-year follow-up. Safety was assessed throughout the trial.

RESULTS

Overall, 49 patients accounted for the modified intent-to-treat and 47 for the PP. Slightly more male than female patients participated; mean age was 57.7 ± 11.4 years in the TIL + IL2 group and 53.5 ± 13.0 years in the abstention group. After 5 years of follow-up, 11/26 patients in the TIL + IL2 group and 13/23 in the abstention group had relapsed. There was no statistical difference between the groups (HR: 0.63 CI 95% [0.28-1.41], p = 0.258), nine patients in the TIL + IL2 and 11 in the abstention group died with no significant difference between the two groups (HR: 0.65 CI95% [0.27 - 1.59], p = 0.34). Safety was good.

CONCLUSION

We did not confirm results of a previous trial. However, ulceration of the primary melanoma may be considered predictive of the efficacy of TIL in melanoma in adjuvant setting, in a manner similar to interferon α.

Targeting Cancer with Genetically Engineered TCR T Cells

The adoptive cell transfer (ACT) of genetically engineered T cell receptor (TCR) T cells is one of the burgeoning fields of immunotherapy, with promising results in current clinical trials. Presently, clinicaltrials.gov has over 200 active trials involving adoptive cell therapy. The ACT of genetically engineered T cells not only allows the ability to select for TCRs with desired properties such as high-affinity receptors and tumor reactivity but to further enhance those receptors allowing for better targeting and killing of cancer cells in patients. Moreover, the addition of genetic material, including cytokines and cytokine receptors, can increase the survival and persistence of the T cell allowing for complete and sustained remission of cancer targets. The potential for improvement in adoptive cell therapy is limitless, with genetic modifications targeting to improve weaknesses of ACT and to thus enhance receptor affinity and functional avidity of the genetically engineered T cells.

Non-genetic engineering of cytotoxic T cells to target IL-4 receptor enhances tumor homing and therapeutic efficacy against melanoma

Adoptive transfer of cytotoxic T lymphocytes (CTLs) has been used as an immunotherapy in melanoma. However, the tumor homing and therapeutic efficacy of transferred CTLs against melanoma remain unsatisfactory. Interleukin-4 receptor (IL-4R) is commonly up-regulated in tumors including melanoma. Here, we studied whether IL-4R-targeted CTLs exhibit enhanced tumor homing and therapeutic efficacy against melanoma. CTLs isolated from mice bearing melanomas were non-genetically engineered with IL4RPep-1, an IL-4R-binding peptide, using a membrane anchor composed of dioleylphosphatidylethanolamine. Compared to control CTLs, IL-4R-targeted CTLs showed higher binding to melanoma cells and in vivo tumor homing. They also exerted a more rapid and robust effector response, including increased cytokine secretion and cytotoxicity against melanoma cells and enhanced reprogramming of M2-type macrophages to M1-type macrophages. Moreover, IL-4R-targeted CTLs efficiently inhibited melanoma growth and reversed the immunosuppressive tumor microenvironment. These results suggest that non-genetically engineered CTLs targeting IL-4R have potential as an adoptive T cell therapy against melanoma.

Long-term intravital imaging of the multicolor-coded tumor microenvironment during combination immunotherapy

The combined-immunotherapy of adoptive cell therapy (ACT) and cyclophosphamide (CTX) is one of the most efficient treatments for melanoma patients. However, no synergistic effects of CTX and ACT on the spatio-temporal dynamics of immunocytes in vivo have been described. Here, we visualized key cell events in immunotherapy-elicited immunoreactions in a multicolor-coded tumor microenvironment, and then established an optimal strategy of metronomic combined-immunotherapy to enhance anti-tumor efficacy. Intravital imaging data indicated that regulatory T cells formed an 'immunosuppressive ring' around a solid tumor. The CTX-ACT combined-treatment elicited synergistic immunoreactions in tumor areas, which included relieving the immune suppression, triggering the transient activation of endogenous tumor-infiltrating immunocytes, increasing the accumulation of adoptive cytotoxic T lymphocytes, and accelerating the infiltration of dendritic cells. These insights into the spatio-temporal dynamics of immunocytes are beneficial for optimizing immunotherapy and provide new approaches for elucidating the mechanisms underlying the involvement of immunocytes in cancer immunotherapy.

DOI:http://dx.doi.org/10.7554/eLife.14756.001

Melanoma is a form of skin cancer that is particularly difficult to treat. A new approach that has shown a lot of promise in treating many different cancers, including melanoma, is called “immunotherapy”. This technique harnesses the immune system – the body’s natural defences that help to protect against infections and disease – to combat cancer.

One powerful type of immunotherapy involves injecting patients with cells called lymphocytes, which form part of the immune system. This is known as adoptive cell therapy and can activate the immune system to fight cancer, helping to shrink tumors. This treatment can be made even more powerful by combining it with a drug called cyclophosphamide and this combination, known as CTX-ACT, is currently one of the most efficient treatments for melanoma. Yet, little information is available to indicate why this treatment is so effective.

Using mice implanted with melanoma cells, Qi, Li et al. sought to understand how CTX-ACT treatment works, with the goal of optimising it to increase its success. The results showed that a protective barrier of immune cells that suppresses the anti-tumor immune response – called an “immunosuppressive ring” – surrounds untreated tumors. CTX-ACT treatment can breakdown these rings, helping to reactivate the anti-tumor immune reaction in the tumors. This allows both the injected and mouse’s own immune cells to move into the tumor and destroy cancer cells.

Qi, Li et al. used their findings to optimise treatment and succeeded in controlling tumor growth in the mice for several weeks. These new insights could be used to improve current immunotherapies, and offer new approaches for investigating the involvement of immune cells in the treatment of a wide range of different cancers.

DOI:http://dx.doi.org/10.7554/eLife.14756.002

Phase I trial of adoptively transferred tumor-infiltrating lymphocyte immunotherapy following concurrent chemoradiotherapy in patients with locoregionally advanced nasopharyngeal carcinoma

Adoptive cell therapy (ACT) for cancers using autologous tumor-infiltrating lymphocytes (TILs) can induce immune responses and antitumor activity in metastatic melanoma patients. Here, we aimed to assess the safety and antitumor activity of ACT using expanded TILs following concurrent chemoradiotherapy (CCRT) in patients with locoregionally advanced nasopharyngeal carcinoma (NPC). Twenty-three newly diagnosed, locoregionally advanced NPC patients were enrolled, of whom 20 received a single-dose of TIL infusion following CCRT. All treated patients were assessed for toxicity, survival and clinical and immunologic responses. Correlations between immunological responses and treatment effectiveness were further studied. Only mild adverse events (AEs), including Grade 3 neutropenia (1/23, 5%) consistent with immune-related causes, were observed. Nineteen of 20 patients exhibited an objective antitumor response, and 18 patients displayed disease-free survival longer than 12 mo after ACT. A measurable plasma Epstein-Barr virus (EBV) load was detected in 14 patients at diagnosis, but a measurable EBV load was not found in patients after one week of ACT, and the plasma EBV load remained undetectable in 17 patients at 6 mo after ACT. Expansion and persistence of T cells specific for EBV antigens in peripheral blood following TIL therapy were observed in 13 patients. The apparent positive correlation between tumor regression and the expansion of T cells specific for EBV was further investigated in four patients. This study shows that NPC patients can tolerate ACT with TILs following CCRT and that this treatment results in sustained antitumor activity and anti-EBV immune responses. A larger phase II trial is in progress.

Adoptive TIL transfer in the adjuvant setting for melanoma: long-term patient survival

Two first analyses of our clinical trial on TIL as adjuvant therapy for melanoma were published in 2002 and 2007. We present here an update of the clinical results after a 17-year median followup. In this trial, disease-free patients were randomly assigned to receive either TIL/IL-2 or IL-2. The relapse-free survival (RFS) was the primary objective. Eighty-eight patients were enrolled. A new analysis performed in May 2013 did not show significant changes in RFS or OS duration. However, our first finding on the association between the number of invaded lymph nodes and TIL effectiveness was strengthened. The Cox model adjusted on this interaction showed for the first time a significant treatment effect when considering the overall population, both on the RFS and OS. Patients treated with TIL had a longer RFS (P = 0.023) or OS (P = 0.020). This study being with a very long followup (17 years), confirmed the association between TIL effectiveness and the number of invaded lymph nodes, indicating that a low tumor burden could be a crucial factor enhancing the curative effect of TIL in possible microscopic residual disease. Moreover, we confirmed that a prolonged survival was associated with the presence of specific TIL and a decrease in Foxp3 expression.

A full GMP process to select and amplify epitope-specific T lymphocytes for adoptive immunotherapy of metastatic melanoma

A number of trials of adoptive transfer of tumor-specific T lymphocytes have been performed in the last 20 years in metastatic melanoma, with increasingly encouraging results as the relevant melanoma antigens were identified and the purity/specificity of injected T cells improved. We have previously described a sorting method of epitope-specific T lymphocytes that uses magnetic beads coated with HLA/peptide complexes and we suggested that this method could be applied to a clinical setting. In the present work, we provide a detailed description of the whole GMP process of sorting and amplification of clinical grade T cells specific for the melanoma antigens Melan-A and MELOE-1. All the reagents used in this process including the sorting reagent were produced in GMP conditions and we document the optimization of the different steps of the process such as peptide stimulation, sorting, and amplification. The optimized procedure, validated in 3 blank runs in a clinical setting, allowed the production of at least 10⁸ pure (>90%) Melan-A- and MELOE-1-specific T cells within 28 days starting with 100 mL of blood from metastatic melanoma patients. This GMP process is thus ready to be used in an upcoming phase I/II clinical trial on metastatic melanoma patients.

Advances in the treatment of metastatic melanoma: adoptive T-cell therapy

Metastatic melanoma is notoriously resistant to chemotherapy and radiotherapy regimens. The prospect for newly diagnosed metastatic melanoma patients is grim, with a median survival of less than 1 year. Currently, the only therapies resulting in long-term disease-free intervals, high-dose interleukin-2 (IL-2) and more recently anti-CTLA-4, work through activation of the immune system. However, with both therapies the response rate is low. Advances in our knowledge of how the immune system interacts with cancer have led to a number of strategies to manipulate anti-tumor immune responses through immunotherapy. This review will focus on one avenue of immunotherapy using the transfer of T cells referred to as "adoptive cell therapy" (ACT), which involves the ex vivo expansion of autologous tumor-specific T cells to large numbers that are ultimately transferred back to the patient to boost anti-tumor immunity. This approach has been shown to be effective in the treatment of virally induced cancers, as well as metastatic melanoma. Recent successes with ACT hold promise and further emphasize the tremendous potential benefit of harnessing the immune system in the fight against cancer.

Adoptive transfer with high-affinity TCR to treat human solid tumors: how to improve the feasibility?

The adoptive transfer of tumor antigen-specific T cells recently achieved clinical efficacy for a fraction of melanoma patients refractory to other therapies. Unfortunately, the application of this strategy to the remaining melanoma and most other cancer patients is hampered by the difficulty to generate high-affinity tumor-reactive T cells. Two strategies are currently developed to extend the feasibility of this therapeutic approach: clinical grade tool production for MHC-peptide multimer-driven sorting of antigen-specific T cells from the endogenous peripheral T cell repertoire and de novo engineering of the missing repertoire by genetic transfer of cloned specific T cell receptor (TCR) into T cells. The expected multiplication of adoptive transfer treatments, by these strategies, and their careful evaluation should enable the cure of a number of otherwise compromised cancer patients and to gain insight into the characteristics of transferred T cells best fitted to eradicate tumor cells, in terms of antigen specificities, phenotype, and functions. In particular, identification of tumor-rejection antigens by this approach would improve the design and efficacy of all immunotherapeutic approaches.

HLA anchor optimization of the melan-A-HLA-A2 epitope within a long peptide is required for efficient cross-priming of human tumor-reactive T cells

The uptake and long-term cross-presentation of tumor Ag long peptides (LP) by dendritic cells (DC) make them attractive cancer vaccine candidates. However, it remains to be established whether LP can prime long-lived tumor-reactive CTL and whether other cell types are able to cross-present them. Using HLA-A2 healthy donor and melanoma patient-derived PBMC, we studied the in vitro cross-priming potential of Melan-A 16-40 LP bearing the HLA-A2-restricted epitope 26-35 or its analog 26-35(A27L) and compared it to the priming capacity of the short analog. We then addressed LP priming capacity in vivo using HLA-A2 mice. We also studied LP cross-presentation by monocyte-derived DC, plasmacytoid DC, monocytes, and B cells. We showed that the modified LP gave rise to high and sustained cross-presentation by monocyte-derived DC. This led to cross priming in vitro and in vivo and to expansion of long-lived tumor-reactive cytotoxic T cells. In contrast, the LP containing the natural 26-35 epitope primed specific T cells poorly, despite its long-lived cross-presentation, and T cells primed against the short analog were short-lived. We further showed that LP cross-presentation is restricted to monocytes and conventional DC. These results document for the first time, to our knowledge, the strong immunogenicity of a human tumor Ag LP. Of note, they underscore that this property is critically dependent on sufficient HLA binding affinity and/or TCR ligand potency of the cross-presented epitope. We conclude that LP fulfilling this requirement should be used as tumor vaccines, together with DC maturating agents, especially the Melan-A 16-40(A27L) LP, for the treatment of HLA-A2(+) melanoma patients.

MART-1- and gp100-expressing and -non-expressing melanoma cells are equally proliferative in tumors and clonogenic in vitro

MART-1 and gp100 are prototypical melanoma antigen (Ag), but their clinical use as vaccines or as targets of cytotoxic lymphocytes achieved modest success. Possible explanations could be that as MART-1 and gp100 are melanocyte differentiation Ag, clonogenic Ag-non-expressing cells would be spared by immune effectors, or that clonogenic cells would be intrinsically resistant to cytotoxic lymphocytes. We therefore analyzed the proliferative status of MART-1/gp100-expressing and -non-expressing cells in biopsies, and the clonogenicity and sensitiveness to cytotoxic lymphocytes of the human cutaneous melanoma cell lines MEL-XY1 and MEL-XY3. Analysis of MART-1/gp100 and Ki-67 expression in 22 melanoma tumors revealed that MART-1/gp100-expressing and -non-expressing cells proliferated competitively. MART-1, gp100, tyrosinase, and CD271 expression were studied in MEL-XY1 and MEL-XY3 colonies. At 7 days, colonies displayed positive, negative, and mixed expression patterns. By 14 days, colonies of different sizes developed, showing cells with different clonogenic potential, and Ag were downregulated, suggesting Ag plasticity. Subcloning of MEL-XY1 colonies showed that Ag expression varied with time without interfering with clonogenicity. Finally, clonogenic, MART-1/gp100-expressing cells were lysed by specific CD8 lymphocytes. Thus, MART-1 and gp100 expression and plasticity would not interfere with proliferation or clonogenicity, and clonogenic cells may be lysed by cytotoxic lymphocytes.

Is antigen specificity the key to efficient adoptive T-cell therapy?

Adoptive transfer of T cells remains a promising approach in melanoma. Initial clinical trials performed with polyclonal tumor-infiltrating lymphocyte gave limited clinical results. Nonetheless, encouraging results have been reported in adjuvant setting (stage III melanoma), and when tumor-infiltrating lymphocytes were associated with lymphodepleting regimens. Specificity of adoptive cell therapy has been achieved with the infusion of antigen specific cytotoxic T-lymphocyte clones, associated with some clinical responses. Antigen specificity can also be obtained by the allogeneic transfer of high-avidity T-cell receptors into autologous T cells. We propose an alternative strategy based on the selection of antigen-specific T cells with magnetic beads coated with HLA–peptide multimers. Future improvements of adoptive melanoma immunotherapy may be achieved by its association with other therapeutic strategies such as targeted therapy against signaling pathways.

Frequent occurrence of high affinity T cells against MELOE-1 makes this antigen an attractive target for melanoma immunotherapy

We recently showed that the infusion of tumor infiltrating lymphocytes specific for the MELOE-1 antigen was associated with a prolonged relapse-free survival for HLA-A2(+) melanoma patients who received tumor infiltrating lymphocytes therapy. Here, we characterized the MELOE-1/A2-specific T-cell repertoire in healthy donors and melanoma patients to further support an immunotherapy targeting this epitope. Using tetramer enrichment followed by multicolor staining, we found that MELOE-1-specific T cells were present in the blood of healthy donors and patients at similar frequencies (around 1 in 1x10(5) CD8(+) cells). These cells mainly displayed a naïve phenotype in 4/6 healthy donors and 3/6 patients, whereas high proportions of memory cells were observed in the remaining individuals of both groups. There was a recurrent usage of the Valpha12.1 chain for 17/18 MELOE-1-specific T-cell clones derived from healthy donors or patients, associated with diverse Vbeta chains and V(D)J junctional sequences. All clones derived from melanoma patients (9/9) were reactive against the MELOE-1(36-44) peptide and against HLA-A2(+) melanoma cell lines. This study documents the existence of a large TCR repertoire specific for the MELOE-1/A2 epitope and its capacity to give rise to antitumor CTL that supports the development of immunotherapies targeting this epitope.

Clinical and immunological responses in metastatic melanoma patients vaccinated with a high-dose poly-epitope vaccine

BACKGROUND

Safety and cellular immunogenicity of rising doses and varying regimens of a poly-epitope vaccine were evaluated in advanced metastatic melanoma. The vaccine comprised plasmid DNA and recombinant modified vaccinia virus Ankara (MVA) both expressing a string (Mel3) of seven HLA.A2/A1 epitopes from five melanoma antigens.

METHODS

Forty-one HLA-A2 positive patients with stage III/IV melanoma were enrolled. Patient groups received one or two doses of DNA.Mel3 followed by escalating doses of MVA.Mel3. Immunisations then continued eight weekly in the absence of disease progression. Epitope-specific CD8+ T cell responses were evaluated using ex-vivo tetramer and IFN-gamma ELISPOT assays. Safety and clinical responses were monitored.

RESULTS

Prime-boost DNA/MVA induced Melan-A-specific CD8+ T cell responses in 22/31 (71%) patients detected by tetramer assay. ELISPOT detected a response to at least one epitope in 10/31 (32%) patients. T cell responder rates were <50% with low-dose DNA/MVA, or MVA alone, rising to 91% with high-dose DNA/MVA. Among eight patients showing evidence of clinical benefit-one PR (24 months+), five SD (5 months+) and two mixed responses-seven had associated immune responses. Melan-A-tetramer+ immunity was associated with a median 8-week increase in time-to-progression (P = 0.037) and 71 week increase in survival (P = 0.0002) compared to non-immunity. High-dose vaccine was well tolerated. The only significant toxicities were flu-like symptoms and injection-site reactions.

CONCLUSIONS

DNA.Mel3 and MVA.Mel3 in a prime-boost protocol generated high rates of immune response to melanoma antigen epitopes. The treatment was well tolerated and the correlation of immune responses with patient outcomes encourages further investigation.

An additional ORF on meloe cDNA encodes a new melanoma antigen, MELOE-2, recognized by melanoma-specific T cells in the HLA-A2 context

We characterized a new melanoma antigen derived from one of the multiple open reading frames (ORFs) of the meloe transcript. The meloe gene is overexpressed in melanomas as compared to other cancer cell lines and normal tissues. The corresponding transcript is rather unusual, in that it does not contain a long unique ORF but multiple short ORFs. We recently characterized a tumor epitope derived from a polypeptide (MELOE-1) encoded by the ORF(1230-1370) and involved in relapse prevention of melanoma patients treated with autologous tumor infiltrating lymphocytes (TIL). Here we show that the ORF(285-404) encodes a polypeptide called MELOE-2 that also generated a HLA-A2 epitope recognized by a melanoma-specific T cell clone derived from the same TIL population from which we derived the MELOE-1-specific T cell clone. We also showed that HLA-A2 melanoma cells were spontaneously recognized by the MELOE-2-specific T cell clone, and we detected the presence of MELOE-2 reactive T cells in another TIL population infused to a patient who remained relapse-free after TIL treatment. These results demonstrate that translation of meloe transcript in melanoma cells can produce at least two immunogenic polypeptides, MELOE-1 and MELOE-2, from two distinct ORFs that could be relevant target for melanoma immunotherapy.

Melanoma cells treated with GGTI and IFN-gamma allow murine vaccination and enhance cytotoxic response against human melanoma cells

Background

Suboptimal activation of T lymphocytes by melanoma cells is often due to the defective expression of class I major histocompatibility antigens (MHC-I) and costimulatory molecules. We have previously shown that geranylgeranyl transferase inhibition (done with GGTI-298) stimulates anti-melanoma immune response through MHC-I and costimulatory molecule expression in the B16F10 murine model [1].

Methodology/Principal Findings

In this study, it is shown that vaccination with mIFN-gand GGTI-298 pretreated B16F10 cells induces a protection against untreated tumor growth and pulmonary metastases implantation. Furthermore, using a human melanoma model (LB1319-MEL), we demonstrated that in vitro treatment with hIFN-γ and GGTI-298 led to the up regulation of MHC-I and a costimulatory molecule CD86 and down regulation of an inhibitory molecule PD-1L. Co-culture experiments with peripheral blood mononuclear cells (PBMC) revealed that modifications induced by hIFN-γ and GGTI-298 on the selected melanoma cells, enables the stimulation of lymphocytes from HLA compatible healthy donors. Indeed, as compared with untreated melanoma cells, pretreatment with hIFN-γ and GGTI-298 together rendered the melanoma cells more efficient at inducing the: i) activation of CD8 T lymphocytes (CD8+/CD69+); ii) proliferation of tumor-specific CD8 T cells (MelanA-MART1/TCR+); iii) secretion of hIFN-γ; and iv) anti-melanoma specific cytotoxic cells.

Conclusions/Significance

These data indicate that pharmacological treatment of melanoma cell lines with IFN-γ and GGTI-298 stimulates their immunogenicity and could be a novel approach to produce tumor cells suitable for vaccination and for stimulation of anti-melanoma effector cells.

MART-1-specific melanoma tumor-infiltrating lymphocytes maintaining CD28 expression have improved survival and expansion capability following antigenic restimulation in vitro

We determined how CD8(+) melanoma tumor-infiltrating lymphocytes (TILs) isolated from two distinct phases of expansion in preparation for adoptive T cell therapy respond to melanoma Ag restimulation. We found that TILs isolated after the rapid expansion protocol (REP) phase, used to generate the final patient TIL infusion product, were hyporesponsive to restimulation with MART-1 peptide-pulsed dendritic cells, with many CD8(+) T cells undergoing apoptosis. Telomere length was shorter post-REP, but of sufficient length to support further cell division. Phenotypic analysis revealed that cell-surface CD28 expression was significantly reduced in post-REP TILs, whereas CD27 levels remained unchanged. Tracking post-REP TIL proliferation by CFSE dilution, as well as sorting for CD8(+)CD28(+) and CD8(+)CD28(-) post-REP subsets, revealed that the few CD28(+) TILs remaining post-REP had superior survival capacity and proliferated after restimulation with MART-1 peptide. An analysis of different supportive cytokine mixtures during the REP found that a combination of IL-15 and IL-21 facilitated comparable expansion of CD8(+) TILs as IL-2, but prevented the loss of CD28 expression with improved responsiveness to antigenic restimulation post-REP. These results suggest that current expansion protocols using IL-2 for melanoma adoptive T cell therapy yields largely CD8(+) T cells unable to persist and divide in vivo following Ag contact. The few CD8(+)CD28(+) T cells that remain may be the only CD8(+) TILs that ultimately survive to repopulate the host and mediate long-term tumor control. A REP protocol using IL-15 and IL-21 may greatly increase the number of CD28(+) TILs capable of long-term persistence.

Ex vivo expansion of tumor specific lymphocytes with IL-15 and IL-21 for adoptive immunotherapy in melanoma

Although T central memory cells have been described as the most effective T-cell subtype against tumor growth, little is known about the requirements needed for their optimal ex vivo generation. Hence, our goal is to establish a protocol that will lead to consistent ex vivo generation of lymphocytes skewed toward a central memory phenotype. Antigen-specific T-cell lines were generated by ex vivo stimulation with Class-I and Class-II melanoma peptide pulsed dendritic cells in the presence of either IL-2 or IL-15 plus IL-21. Tumor specific lymphocytes of both central memory and effector characteristics were consistently generated from healthy donors and melanoma patients. IL15/IL21 cultures result in a cell population with a lower proportion of CD4(+)CD25(high)FoxP3(+) regulatory cells and higher number of CD8(+) and CD56(+) cells, and consequently render a higher yield of cells with a greater cytolytic activity and IFN-gamma production against melanoma cell lines.

A new tyrosinase epitope recognized in the HLA-B*4002 context by CTL from melanoma patients

Melanoma reactive CTL were obtained by stimulating PBL from a melanoma patient in remission since 1994 following adjuvant TIL immunotherapy, with the autologous melanoma cell line. They were cloned by limiting dilution. One CTL clone recognized melanoma cell lines expressing tyrosinase and the B*4002 molecule, either spontaneously or upon transfection. We demonstrated that this clone recognizes the tyrosinase-derived nonapeptide 316-324 (ADVEFCLSL) and the overlapping decapeptide 315-324 (SADVEFCLSL). We derived two distinct additional specific CTL clones from this same patient that were also reactive against B*4002 melanoma cell lines, suggesting a relative diversity of this specific repertoire in this patient. Stimulating PBMC derived from four additional B*4002 melanoma patients with the tyrosinase 316-324 nonapeptide induced the growth of specific cells for two of the patients, demonstrating the immunogenicity of this new epitope. Our data show that this nonapeptide is a new tool that could be used to generate melanoma-specific T cells for adoptive immunotherapy or serve as a peptide vaccine for HLA-B*4002 melanoma patients.

Skin layer-specific Melan-A expression during progression of human cutaneous melanoma: implications for diagnostic applications of the marker

Melan-A is widely used in the diagnostics of human melanoma. The immunogenicity of this glycoprotein makes it a potential target in immunotherapy and several authors have suggested its potential as a prognostic factor. Up to now there has been no clear direct evidence of changes of Melan-A expression during the progression of melanoma. We have performed objective immunohistochemical assessment of the expression of Melan-A in benign naevi and melanomas at different stages of progression. Our results show a complex pattern of changes in the expression of Melan-A in melanomas depending on the location of melanoma cells within individual skin layers. The expression of the antigen during tumour progression significantly decreases for melanoma cells located in the granular/spinous layer (r=-0.94, P=0.02) and increases for the papillary layer (r=0.99, P=0.002) and reticular layer (r=0.89, P=0.04). It should also be emphasized that from the Clark II level of progression the melanomas can be detected with high sensitivity and specificity using a simple cut-off test based on the determination of Melan-A expression in tumour cells located within the papillary layer.

MELOE-1 is a new antigen overexpressed in melanomas and involved in adoptive T cell transfer efficiency

A cytotoxic T lymphocyte (CTL) clone was derived from a tumor-infiltrating lymphocyte (TIL) population infused to a melanoma patient who remained relapse free for 10 yr after this adoptive transfer. This clone recognized all melanoma cell lines tested and, to a lower extent, melanocytes, in the context of human histocompatibility leukocyte antigen A2 (HLA-A2), but it did not recognize other tumor cell types. The gene coding for the antigen recognized by this clone was identified by the screening of a melanoma complementary DNA expression library. This antigen is overexpressed in melanomas, compared with other cancer cell lines and healthy tissues, and was thus called melanoma-overexpressed antigen (meloe). Remarkably, the structure of meloe was unusual, with multiple short open reading frames (ORFs). The peptide recognized by the CTL clone was encoded by one of these ORFs, called MELOE-1. Using a specific HLA-A2/peptide tetramer, we showed a correlation between the infusion of TILs containing MELOE-1–specific T cells and relapse prevention in HLA-A2 patients. Indeed, 5 out of 9 patients who did not relapse were infused with TILs that contained MELOE-1–specific T cells, whereas 0 out of the 21 patients who relapsed was infused with such TIL-containing lymphocytes. Overall, our results suggest that this new antigen is involved in immunosurveillance and, thus, represents an attractive target for immunotherapy protocols of melanoma.

A HLA-Cw*0701 restricted Melan-A/MART1 epitope presented by melanoma tumor cells to CD8+ tumor infiltrating lymphocytes

Melan-A/MART1 is a melanocytic differentiation antigen recognized on melanoma tumor cells by CD8+ and CD4+ T cells. In this study, we describe a new epitope of this protein recognized in the context of HLA-Cw*0701 molecules by a CD8+ tumor infiltrating lymphocyte (TIL) clone. This CD8+ TIL clone specifically recognized and killed a fraction of melanoma cells lines expressing Melan-A/MART1 and HLA-Cw*0701. We further show that the Melan-A/MART1(51-61) peptide is the optimal peptide recognized by this clone. Together, these data significantly enlarge the fraction of melanoma patients susceptible to benefit from a Melan-A/MART1 vaccine approach.

Oncolytic virotherapy for malignant melanoma with herpes simplex virus type 1 mutant HF10

BACKGROUND

Many viruses have been engineered and evaluated for their potential as therapeutic agents in the treatment of malignant neoplasm, including malignant melanoma.

OBJECTIVE

In this study, we investigated the efficacy of HF10, an attenuated, replication-competent HSV, in immunocompetent animal models with malignant melanoma.

METHODS

For in vitro study, viral cytotoxicity assays and replication assays were performed both in human and mouse melanoma cells. For the study in vivo, intraperitoneally disseminated or subcutaneous melanoma models were prepared in DBA/2 mice using clone M3 cells, then HF10 was inoculated intraperitoneally or intratumorally. Therapeutic efficacy of HF10 was assessed by survival, tumor growth, and histopathological analysis.

RESULTS

HF10 infection produced cytolytic effects in melanoma cells at various multiplicities of infection (MOI). In the intraperitoneal melanoma model, all mice survived when given intraperitoneal injections of HF10 compared with 100% fatality in the control mice. In the subcutaneous tumor model, intratumoral inoculation of HF10 significantly reduced tumor growth. Histology and immunohistochemistry showed tumor lysis and inflammatory cell infiltration after intratumoral HF10 inoculation. Viral antigen was retained at the inoculation site until 7 days post-infection. HF10-treated intraperitoneal tumor mice were also protected against tumor rechallenge. HF10 also affected the non-inoculated contralateral tumor when injected into the ipsilateral tumor of mice, suggesting that HF10 can induce systemic antitumor immune responses in mice.

CONCLUSION

Oncolytic viral therapy using HF10 was effective in melanoma mouse models, and intratumoral injection of HF10 induced systemic antitumor responses. These results suggest that HF10 is a promising agent for the treatment of advanced melanoma.

Long-term follow-up of patients treated by adoptive transfer of melanoma tumor-infiltrating lymphocytes as adjuvant therapy for stage III melanoma

The first analysis of our clinical trial on interest of using tumor-infiltrating lymphocytes (TIL) as adjuvant therapy for stage III (regional lymph nodes) melanoma was published in 2002 [5]. The aim of this paper is to update clinical results of 7 years of follow-up after the last treated patient. In the trial conducted between December 1993 and January 1999, patients without any detectable metastases after lymph node excision were randomly assigned to receive either TIL plus interleukin-2 (IL-2) for 2 months, or IL-2 only. The duration of the relapse-free interval was the primary objective. Eighty-eight patients were enrolled in the study. Currently, the last analysis performed in June 2006, after a median follow-up of 114.8 months, did not show change of non-significant extension of the relapse-free interval or overall survival. However, this second analysis strengthens our first hypothesis about the relationship between number of invaded lymph nodes and TIL treatment effectiveness. In the group with only one invaded lymph node, the estimated relapse rate was significantly lower (P (adjusted) = 0.0219) and the overall survival was increased (P (adjusted) = 0.0125) in the TIL+IL-2 arm compared with the IL-2 only arm. No differences between the two arms, either with regard to the duration of disease-free survival (P (adjusted) = 0.38) or overall survival (P (adjusted) = 0.43), were noted in the group with more than one invaded lymph node, whatever the number of invaded lymph nodes. Treatment was compatible with normal daily activity. This study, with a very long follow up (median of almost 10 years), postulates for the first time relationship between TIL efficiency in stage III melanoma (AJCC) and number of invaded lymph nodes, indicating that tumor burden might be a crucial factor in the production of an effective in vitro expansion of T cells specific for autologous tumor antigen, a finding which could be of value in future vaccine development for the treatment of melanoma.

In vivo imaging of T cell delivery to tumors after adoptive transfer therapy

Adoptive transfer therapy of in vitro-expanded tumor-specific cytolytic T lymphocytes (CTLs) can mediate objective cancer regression in patients. Yet, technical limitations hamper precise monitoring of posttherapy T cell responses. Here we show in a mouse model that fused single photon emission computed tomography and x-ray computed tomography allows quantitative whole-body imaging of (111)In-oxine-labeled CTLs at tumor sites. Assessment of CTL localization is rapid, noninvasive, three-dimensional, and can be repeated for longitudinal analyses. We compared the effects of lymphodepletion before adoptive transfer on CTL recruitment and report that combined treatment increased intratumoral delivery of CTLs and improved antitumor efficacy. Because (111)In-oxine is a Food and Drug Administration-approved clinical agent, and human SPECT-CT systems are available, this approach should be clinically translatable, insofar as it may assess the efficacy of immunization procedures in individual patients and lead to development of more effective therapies.