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Cancer testis antigens are ideal for tumor immunotherapy due to their testis-restricted expression. We previously showed that an immunotherapeutic vaccine targeting the germ cell-specific transcription factor BORIS (CTCFL) was highly effective in treating aggressive breast cancer in the 4T1 mouse model. Here, we further tested the therapeutic efficacy of BORIS in a rat 13762 breast cancer model. We generated a recombinant VEE-VRP (Venezuelan Equine Encephalitis-derived replicon particle) vector-expressing modified rat BORIS lacking a DNA-binding domain (VRP-mBORIS). Rats were inoculated with the 13762 cells, immunized with VRP-mBORIS 48 h later, and then, subsequently, boosted at 10-day intervals. The Kaplan-Meier method was used for survival analysis. Cured rats were re-challenged with the same 13762 cells. We demonstrated that BORIS was expressed in a small population of the 13762 cells, called cancer stem cells. Treatment of rats with VRP-BORIS suppressed tumor growth leading to its complete disappearance in up to 50% of the rats and significantly improved their survival. This improvement was associated with the induction of BORIS-specific cellular immune responses measured by T-helper cell proliferation and INFγ secretion. The re-challenging of cured rats with the same 13762 cells indicated that the immune response prevented tumor growth. Thus, a therapeutic vaccine against rat BORIS showed high efficacy in treating the rat 13762 carcinoma. These data suggest that targeting BORIS can lead to the elimination of mammary tumors and cure animals even though BORIS expression is detected only in cancer stem cells.
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Neoplasias Mamarias Animales , Vacunas , Animales , Masculino , Ratones , Ratas , Proteínas de Unión al ADN/metabolismo , Inmunoterapia/métodos , Factores de TranscripciónRESUMEN
CD8+ T cells are an essential part of the immune system and play a vital role in defending against tumors and infections. The phosphoinositide-3-kinase (PI3K), especially class I, is involved in numerous interrelated signaling pathways which control CD8+ T cell development, maturation, migration, activation, and differentiation. While CD8+ T lymphocytes express all class I PI3K isoforms (PI3Kα, PI3Kß, PI3Kδ, and PI3Kγ), isoform-specific functions, especially for PI3Kα and PI3Kß have not been fully elucidated. A few studies suggest the important role of p110δ and p110γ in CD8+ T cell activation, signaling, chemotaxis and function and several clinical trials are currently testing the effect of isoform-specific inhibitors in various types of cancers, including Indolent Non-Hodgkin Lymphoma, Peripheral T cell Lymphoma, Chronic Lymphocytic Leukemia, Small Lymphocytic Lymphoma, non-small cell lung carcinoma (NSCLC), head & neck cancer, and breast cancer. This chapter summarizes current knowledge of the roles of various PI3K isoforms and downstream signaling pathways in regulating CD8+ T cell fate, including cell proliferation, migration, and memory generation. We also discuss certain clinical trials employing PI3K inhibitors for cancer therapy, their limitations, and future perspectives.
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Leucemia Linfocítica Crónica de Células B , Fosfatidilinositol 3-Quinasas , Linfocitos T CD8-positivos , Humanos , Fosfatidilinositol 3-Quinasa , Fosfatidilinositol 3-Quinasas/metabolismo , Fosfatidilinositoles , Isoformas de Proteínas/genéticaRESUMEN
The immunosuppressive tumor microenvironment (TME) does not allow generation and expansion of antitumor effector cells. One of the potent immunosuppressive factors present in the TME is the indoleamine-pyrrole 2,3-dioxygenase (IDO) enzyme, produced mainly by cancer cells and suppressive immune cells of myeloid origin. In fact, IDO+ myeloid-derived suppressor cells (MDSC) and dendritic cells (DC) tend to be more suppressive than their IDO- counterparts. Hence, therapeutic approaches that would target the IDO+ cells in the TME, while sparing the antigen-presenting functions of IDO- myeloid populations, are needed. Using an IDO-specific peptide vaccine (IDO vaccine), we explored the possibility of generating effector cells against IDO and non-IDO tumor-derived antigens. For this, IDO-secreting (B16F10 melanoma) and non-IDO-secreting (TC-1) mouse tumor models were employed. We showed that the IDO vaccine significantly reduced tumor growth and enhanced survival of mice in both the tumor models, which associated with a robust induction of IDO-specific effector cells in the TME. The IDO vaccine significantly enhanced the antitumor efficacy of non-IDO tumor antigen-specific vaccines, leading to an increase in the number of total and antigen-specific activated CD8+ T cells (IFNγ+ and granzyme B+). Treatment with the IDO vaccine significantly reduced the numbers of IDO+ MDSCs and DCs, and immunosuppressive regulatory T cells in both tumor models, resulting in enhanced therapeutic ratios. Together, we showed that vaccination against IDO is a promising therapeutic option for both IDO-producing and non-IDO-producing tumors. The IDO vaccine selectively ablates the IDO+ compartment in the TME, leading to a significant enhancement of the immune responses against other tumor antigen-specific vaccines.
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Vacunas contra el Cáncer , Melanoma , Animales , Antígenos de Neoplasias , Indolamina-Pirrol 2,3,-Dioxigenasa , Melanoma/tratamiento farmacológico , Ratones , Microambiente TumoralRESUMEN
Regenerative stem cell-like memory (TSCM) CD8+ T cells persist longer and produce stronger effector functions. We found that MEK1/2 inhibition (MEKi) induces TSCM that have naive phenotype with self-renewability, enhanced multipotency and proliferative capacity. This is achieved by delaying cell division and enhancing mitochondrial biogenesis and fatty acid oxidation, without affecting T cell receptor-mediated activation. DNA methylation profiling revealed that MEKi-induced TSCM cells exhibited plasticity and loci-specific profiles similar to bona fide TSCM isolated from healthy donors, with intermediate characteristics compared to naive and central memory T cells. Ex vivo, antigenic rechallenge of MEKi-treated CD8+ T cells showed stronger recall responses. This strategy generated T cells with higher efficacy for adoptive cell therapy. Moreover, MEKi treatment of tumor-bearing mice also showed strong immune-mediated antitumor effects. In conclusion, we show that MEKi leads to CD8+ T cell reprogramming into TSCM that acts as a reservoir for effector T cells with potent therapeutic characteristics.
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Antineoplásicos/farmacología , Linfocitos T CD8-positivos/efectos de los fármacos , Memoria Inmunológica/efectos de los fármacos , Inmunoterapia Adoptiva , Quinasas de Proteína Quinasa Activadas por Mitógenos/antagonistas & inhibidores , Neoplasias/terapia , Células Madre/citología , Animales , Linfocitos T CD8-positivos/citología , Linfocitos T CD8-positivos/inmunología , Ciclo Celular/efectos de los fármacos , Humanos , Memoria Inmunológica/inmunología , Ratones , Ratones Endogámicos C57BL , Mitocondrias/efectos de los fármacos , Receptores de Antígenos de Linfocitos T/fisiología , Microambiente TumoralRESUMEN
Cell therapy using T cell receptors (TCRs) and chimeric antigen receptors (CARs) represents a new wave of immunotherapies garnering considerable attention and investment. Further progress in this area of medicine depends in part on improving the functional capabilities of the engineered components, while maintaining the overall size of recombinant constructs to ensure their compatibility with existing gene delivery vehicles. We describe a single-variable-domain TCR (svd TCR) that utilizes only the variable domain of the ß chain (Vß). This Vß module not only works in TCR and CAR formats, but also can be used to create single-chain bispecific CARs and TCRs. Comparison of individual ligand-binding Vß domains in different formats suggests that the lone Vß sequence controls the sensitivity and a major part of the specificity of the CAR or TCR construct, regardless of signaling format, in Jurkat and primary T cells.
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Región Variable de Inmunoglobulina/inmunología , Inmunoterapia Adoptiva/métodos , Neoplasias/terapia , Receptores de Antígenos de Linfocitos T alfa-beta/inmunología , Receptores Quiméricos de Antígenos/inmunología , Linfocitos T/trasplante , Ingeniería Celular , Células HEK293 , Humanos , Región Variable de Inmunoglobulina/genética , Células Jurkat , Ligandos , Neoplasias/inmunología , Cultivo Primario de Células , Receptores de Antígenos de Linfocitos T alfa-beta/genética , Receptores Quiméricos de Antígenos/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Linfocitos T/inmunología , Transfección , Escape del TumorRESUMEN
SANTAVAC is an antigen composition developed via proteomics and cell culture technology that is intended for the development of cancer vaccines against various solid tumors. Its mechanism of action is based on the heterogeneity of endothelial cells, the polypeptides of which are similar to the surface antigens of tumor-vessel cells, allowing targeted destruction by vaccination. While research and development work with SANTAVAC is ongoing, the existing data provide strong evidence that allogeneic SANTAVAC is an ideal candidate for the development of cancer vaccines with significant efficacy and safety. The SANTAVAC compositions described here demonstrated the ability to inhibit the growth of tumor vessel-specific endothelial cells up to 60 fold, with minimal effect on normal vasculature. Innovation, background, description of product development, and summary of nonclinical studies with SANTAVAC to date are presented in this review.
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Understanding resistance to antibody to programmed cell death protein 1 (PD-1; anti-PD-1) is crucial for the development of reversal strategies. In anti-PD-1-resistant models, simultaneous anti-PD-1 and vaccine therapy reversed resistance, while PD-1 blockade before antigen priming abolished therapeutic outcomes. This was due to induction of dysfunctional PD-1+CD38hi CD8+ cells by PD-1 blockade in suboptimally primed CD8 cell conditions induced by tumors. This results in erroneous T cell receptor signaling and unresponsiveness to antigenic restimulation. On the other hand, PD-1 blockade of optimally primed CD8 cells prevented the induction of dysfunctional CD8 cells, reversing resistance. Depleting PD-1+CD38hi CD8+ cells enhanced therapeutic outcomes. Furthermore, non-responding patients showed more PD-1+CD38+CD8+ cells in tumor and blood than responders. In conclusion, the status of CD8+ T cell priming is a major contributor to anti-PD-1 therapeutic resistance. PD-1 blockade in unprimed or suboptimally primed CD8 cells induces resistance through the induction of PD-1+CD38hi CD8+ cells that is reversed by optimal priming. PD-1+CD38hi CD8+ cells serve as a predictive and therapeutic biomarker for anti-PD-1 treatment. Sequencing of anti-PD-1 and vaccine is crucial for successful therapy.
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ADP-Ribosil Ciclasa 1/metabolismo , Linfocitos T CD8-positivos/inmunología , Resistencia a Antineoplásicos/inmunología , Glicoproteínas de Membrana/metabolismo , Neoplasias/inmunología , Receptor de Muerte Celular Programada 1/inmunología , ADP-Ribosil Ciclasa 1/genética , Animales , Anticuerpos/inmunología , Linfocitos T CD8-positivos/patología , Vacunas contra el Cáncer/inmunología , Línea Celular Tumoral , Resistencia a Antineoplásicos/genética , Femenino , Humanos , Inmunoterapia/métodos , Glicoproteínas de Membrana/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Microambiente Tumoral/inmunologíaRESUMEN
Although an immune response to tumors may be generated using vaccines, so far, this approach has only shown minimal clinical success. This is attributed to the tendency of cancer to escape immune surveillance via multiple immune suppressive mechanisms. Successful cancer immunotherapy requires targeting these inhibitory mechanisms along with enhancement of antigen-specific immune responses to promote sustained tumor-specific immunity. Here, we evaluated the effect of indoximod, an inhibitor of the immunosuppressive indoleamine-(2,3)-dioxygenase (IDO) pathway, on antitumor efficacy of anti-OX40 agonist in the context of vaccine in the IDO- TC-1 tumor model. We demonstrate that although the addition of anti-OX40 to the vaccine moderately enhances therapeutic efficacy, incorporation of indoximod into this treatment leads to enhanced tumor regression and cure of established tumors in 60% of treated mice. We show that the mechanisms by which the IDO inhibitor leads to this therapeutic potency include (i) an increment of vaccine-induced tumor-infiltrating effector T cells that is facilitated by anti-OX40 and (ii) a decrease of IDO enzyme activity produced by nontumor cells within the tumor microenvironment that results in enhancement of the specificity and the functionality of vaccine-induced effector T cells. Our findings suggest a translatable strategy to enhance the overall efficacy of cancer immunotherapy. Cancer Immunol Res; 6(2); 201-8. ©2018 AACR.
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Antígenos de Diferenciación/farmacología , Neoplasias Pulmonares/tratamiento farmacológico , Triptófano Oxigenasa/antagonistas & inhibidores , Triptófano/análogos & derivados , Animales , Antígenos de Diferenciación/inmunología , Vacunas contra el Cáncer/inmunología , Vacunas contra el Cáncer/farmacología , Epítopos de Linfocito T , Femenino , Humanos , Inmunoterapia/métodos , Neoplasias Pulmonares/inmunología , Ratones , Ratones Endogámicos C57BL , Triptófano/farmacología , Triptófano Oxigenasa/inmunología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
BACKGROUND: We previously demonstrated that in addition to generating an antigen-specific immune response, Listeria monocytogenes (Lm)-based immunotherapy significantly reduces the ratio of regulatory T cells (Tregs)/CD4+ and myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment. Since Lm-based immunotherapy is able to inhibit the immune suppressive environment, we hypothesized that combining this treatment with agonist antibody to a co-stimulatory receptor that would further boost the effector arm of immunity will result in significant improvement of anti-tumor efficacy of treatment. METHODS: Here we tested the immune and therapeutic efficacy of Listeria-based immunotherapy combination with agonist antibody to glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR) in TC-1 mouse tumor model. We evaluated the potency of combination on tumor growth and survival of treated animals and profiled tumor microenvironment for effector and suppressor cell populations. RESULTS: We demonstrate that combination of Listeria-based immunotherapy with agonist antibody to GITR synergizes to improve immune and therapeutic efficacy of treatment in a mouse tumor model. We show that this combinational treatment leads to significant inhibition of tumor-growth, prolongs survival and leads to complete regression of established tumors in 60% of treated animals. We determined that this therapeutic benefit of combinational treatment is due to a significant increase in tumor infiltrating effector CD4+ and CD8+ T cells along with a decrease of inhibitory cells. CONCLUSION: To our knowledge, this is the first study that exploits Lm-based immunotherapy combined with agonist anti-GITR antibody as a potent treatment strategy that simultaneously targets both the effector and suppressor arms of the immune system, leading to significantly improved anti-tumor efficacy. We believe that our findings depicted in this manuscript provide a promising and translatable strategy that can enhance the overall efficacy of cancer immunotherapy.
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Anticuerpos Monoclonales/administración & dosificación , Proteína Relacionada con TNFR Inducida por Glucocorticoide/agonistas , Inmunoterapia/métodos , Listeria monocytogenes/inmunología , Neoplasias Pulmonares/terapia , Células Supresoras de Origen Mieloide/efectos de los fármacos , Animales , Anticuerpos Monoclonales/farmacología , Linfocitos T CD4-Positivos/efectos de los fármacos , Linfocitos T CD8-positivos/efectos de los fármacos , Línea Celular Tumoral , Terapia Combinada , Humanos , Neoplasias Pulmonares/inmunología , Ratones , Linfocitos T Reguladores/efectos de los fármacos , Resultado del Tratamiento , Microambiente Tumoral/efectos de los fármacos , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Combination therapies that depend on checkpoint inhibitor antibodies (Abs) such as for PD-1 or its ligand (PD-L1) together with immune stimulatory agonist Abs like anti-OX40 are being tested in the clinic to achieve improved antitumor effects. Here, we studied the potential therapeutic and immune effects of one such combination: Ab to PD-1 with agonist Ab to OX40/vaccine. We tested the antitumor effects of different treatment sequencing of this combination. We report that simultaneous addition of anti-PD-1 to anti-OX40 negated the antitumor effects of OX40 Ab. Antigen-specific CD8+ T-cell infiltration into the tumor was diminished, the resultant antitumor response weakened, and survival reduced. Although we observed an increase in IFNγ-producing E7-specifc CD8+ T cells in the spleens of mice treated with the combination of PD-1 blockade with anti-OX40/vaccine, these cells underwent apoptosis both in the periphery and the tumor. These results indicate that anti-PD-1 added at the initiation of therapy exhibits a detrimental effect on the positive outcome of anti-OX40 agonist Ab. These findings have important implications on the design of combination immunotherapy for cancer, demonstrating the need to test treatment combination and sequencing before moving to the clinic. Cancer Immunol Res; 5(9); 755-66. ©2017 AACR.
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Antígenos de Diferenciación/inmunología , Antígeno B7-H1/inmunología , Inmunoterapia , Neoplasias Pulmonares/inmunología , Receptor de Muerte Celular Programada 1/inmunología , Animales , Anticuerpos/administración & dosificación , Anticuerpos/inmunología , Apoptosis/inmunología , Linfocitos T CD8-positivos/efectos de los fármacos , Linfocitos T CD8-positivos/inmunología , Vacunas contra el Cáncer/administración & dosificación , Vacunas contra el Cáncer/inmunología , Línea Celular Tumoral , Terapia Combinada , Modelos Animales de Enfermedad , Humanos , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/terapia , Ratones , Receptor de Muerte Celular Programada 1/antagonistas & inhibidoresRESUMEN
Inhibition of specific Akt isoforms in CD8+ T cells promotes favored differentiation into memory versus effector cells, the former of which are superior in mediating antitumor immunity. In this study, we investigated the role of upstream PI3K isoforms in CD8+ T-cell differentiation and assessed the potential use of PI3K isoform-specific inhibitors to favorably condition CD8+ T cells for adoptive cell therapy. The phenotype and proliferative ability of tumor antigen-specific CD8+ T cells was assessed in the presence of PI3K-α, -ß, or -δ inhibitors. Inhibition of PI3K-δ, but not PI3K-α or PI3K-ß, delayed terminal differentiation of CD8+ T cells and maintained the memory phenotype, thus enhancing their proliferative ability and survival while maintaining their cytokine and granzyme B production ability. This effect was preserved in vivo after ex vivo PI3K-δ inhibition in CD8+ T cells destined for adoptive transfer, enhancing their survival and also the antitumor therapeutic activity of a tumor-specific peptide vaccine. Our results outline a mechanism by which inhibitions of a single PI3K isoform can enhance the proliferative potential, function, and survival of CD8+ T cells, with potential clinical implications for adoptive cell transfer and vaccine-based immunotherapies. Cancer Res; 77(15); 4135-45. ©2017 AACR.
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Linfocitos T CD8-positivos/inmunología , Inmunoterapia Adoptiva/métodos , Melanoma Experimental/patología , Inhibidores de las Quinasa Fosfoinosítidos-3 , Animales , Linfocitos T CD8-positivos/enzimología , Diferenciación Celular/efectos de los fármacos , Fosfatidilinositol 3-Quinasa Clase I , Inhibidores Enzimáticos/farmacología , Femenino , Memoria Inmunológica/inmunología , Activación de Linfocitos/inmunología , Melanoma Experimental/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones TransgénicosRESUMEN
To modulate T-cell function for cancer therapy, one challenge is to selectively attenuate regulatory but not conventional CD4+ T-cell subsets [regulatory T cell (Treg) and conventional T cell (Tconv)]. In this study, we show how a functional dichotomy in Class IA PI3K isoforms in these two subsets of CD4+ T cells can be exploited to target Treg while leaving Tconv intact. Studies employing isoform-specific PI3K inhibitors and a PI3Kδ-deficient mouse strain revealed that PI3Kα and PI3Kß were functionally redundant with PI3Kδ in Tconv. Conversely, PI3Kδ was functionally critical in Treg, acting there to control T-cell receptor signaling, cell proliferation, and survival. Notably, in a murine model of lung cancer, coadministration of a PI3Kδ-specific inhibitor with a tumor-specific vaccine decreased numbers of suppressive Treg and increased numbers of vaccine-induced CD8 T cells within the tumor microenvironment, eliciting potent antitumor efficacy. Overall, our results offer a mechanistic rationale to employ PI3Kδ inhibitors to selectively target Treg and improve cancer immunotherapy. Cancer Res; 77(8); 1892-904. ©2017 AACR.
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Linfocitos T CD4-Positivos/enzimología , Linfocitos T CD4-Positivos/inmunología , Neoplasias Experimentales/terapia , Fosfatidilinositol 3-Quinasas/inmunología , Linfocitos T Reguladores/enzimología , Linfocitos T Reguladores/inmunología , Animales , Linfocitos T CD8-positivos/inmunología , Vacunas contra el Cáncer/inmunología , Vacunas contra el Cáncer/farmacología , Sinergismo Farmacológico , Inhibidores Enzimáticos/farmacología , Femenino , Inmunoterapia/métodos , Isoenzimas , Activación de Linfocitos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Neoplasias Experimentales/enzimología , Neoplasias Experimentales/inmunología , Fosfatidilinositol 3-Quinasas/genética , Inhibidores de las Quinasa Fosfoinosítidos-3 , Purinas/farmacología , Quinazolinonas/farmacología , Transducción de Señal/inmunología , Subgrupos de Linfocitos T/inmunologíaRESUMEN
Cancer immunotherapy has proven to be a potent treatment modality. Although often successful in generating antitumor immune responses, cancer immunotherapy is frequently hindered by tumor immune-escape mechanisms. Among immunosuppressive strategies within the tumor microenvironment, suppressive immune regulatory cells play a key role in promoting tumor progression through inhibiting the effector arm of the immune response. Targeting these suppressive cells can greatly enhance antitumor immune therapies, hence augmenting a highly effective therapeutic antitumor response. Several approaches are being tested to enhance the effector arm of the immune system while simultaneously inhibiting the suppressor arm. Some of these approaches are none other than traditional drugs repurposed as immune modulators. Cyclophosphamide, an old-school chemotherapeutic agent used across a wide range of malignancies, was found to be a potent immune modulator that targets suppressive regulatory immune cells within the tumor microenvironment while enhancing effector cells. Preclinical and clinical findings have confirmed the ability of low doses of cyclophosphamide to selectively deplete regulatory T cells while enhancing effector and memory cytotoxic T cells within the tumor microenvironment. These immune effects translate to suppressed tumor growth and enhanced survival, evidence of antitumor therapeutic efficacy. This article discusses the reincarnation of cyclophosphamide as an immune modulator that augments novel immunotherapeutic approaches. Cancer Immunol Res; 4(5); 377-82. ©2016 AACR.
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Antineoplásicos Alquilantes/uso terapéutico , Ciclofosfamida/uso terapéutico , Factores Inmunológicos/uso terapéutico , Inmunoterapia/métodos , Neoplasias/tratamiento farmacológico , Antineoplásicos Alquilantes/administración & dosificación , Antineoplásicos Alquilantes/farmacología , Ciclofosfamida/administración & dosificación , Ciclofosfamida/farmacología , Relación Dosis-Respuesta a Droga , Reposicionamiento de Medicamentos/métodos , Humanos , Factores Inmunológicos/administración & dosificación , Factores Inmunológicos/farmacología , Neoplasias/inmunología , Subgrupos de Linfocitos T/efectos de los fármacosRESUMEN
Constitutive activation of the KRAS oncogene in human malignancies is associated with aggressive tumor growth and poor prognosis. Similar to other oncogenes, KRAS acts in a cell-intrinsic manner to affect tumor growth or survival. However, we describe here a different, cell-extrinsic mechanism through which mutant KRAS contributes to tumor development. Tumor cells carrying mutated KRAS induced highly suppressive T cells, and silencing KRAS reversed this effect. Overexpression of the mutant KRAS(G12V)gene in wild-type KRAS tumor cells led to regulatory T-cell (Treg) induction. We also demonstrate that mutant KRAS induces the secretion of IL10 and transforming growth factor-ß1 (both required for Treg induction) by tumor cells through the activation of the MEK-ERK-AP1 pathway. Finally, we report that inhibition of KRAS reduces the infiltration of Tregs in KRAS-driven lung tumorigenesis even before tumor formation. This cell-extrinsic mechanism allows tumor cells harboring a mutant KRAS oncogene to escape immune recognition. Thus, an oncogene can promote tumor progression independent of its transforming activity by increasing the number and function of Tregs. This has a significant clinical potential, in which targeting KRAS and its downstream signaling pathways could be used as powerful immune modulators in cancer immunotherapy.
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Mutación , Fenotipo , Subgrupos de Linfocitos T/metabolismo , Linfocitos T Reguladores/metabolismo , Proteínas ras/genética , Animales , Biomarcadores , Línea Celular Tumoral , Transformación Celular Neoplásica/genética , Modelos Animales de Enfermedad , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Humanos , Inmunofenotipificación , Interleucina-10/metabolismo , Neoplasias Pulmonares/inmunología , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Linfocitos Infiltrantes de Tumor/inmunología , Linfocitos Infiltrantes de Tumor/metabolismo , Ratones , Transducción de Señal , Subgrupos de Linfocitos T/inmunología , Linfocitos T Reguladores/inmunología , Factor de Transcripción AP-1/metabolismo , Factor de Crecimiento Transformador beta1/metabolismoRESUMEN
Novel strategies for cancer treatment involving blockade of immune inhibitors have shown significant progress toward understanding the molecular mechanism of tumor immune evasion. The preclinical findings and clinical responses associated with programmed death-1 (PD-1) and PD-ligand pathway blockade seem promising, making these targets highly sought for cancer immunotherapy. In fact, the anti-PD-1 antibodies, pembrolizumab and nivolumab, were recently approved by the US FDA for the treatment of unresectable and metastatic melanoma resistant to anticytotoxic T-lymphocyte antigen-4 antibody (ipilimumab) and BRAF inhibitor. Here, we discuss strategies of combining PD-1/PD-ligand interaction inhibitors with other immune checkpoint modulators and standard-of-care therapy to break immune tolerance and induce a potent antitumor activity, which is currently a research area of key scientific pursuit.
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Anticuerpos Monoclonales Humanizados/uso terapéutico , Anticuerpos Monoclonales/uso terapéutico , Antígeno B7-H1/antagonistas & inhibidores , Inmunoterapia/métodos , Melanoma/tratamiento farmacológico , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Animales , Antígeno B7-H1/inmunología , Humanos , Ipilimumab , Melanoma/inmunología , Metástasis de la Neoplasia , Nivolumab , Receptor de Muerte Celular Programada 1/inmunología , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Proteínas Proto-Oncogénicas B-raf/inmunologíaRESUMEN
The CD8 + T-cell response comprises terminally differentiated effector cells and antigen-experienced memory T cells. The latter encompass central (TCM) and effector (TEM) memory cells. TCM cells are superior in their protection against viral and bacterial challenges and mediation of antitumor immunity due to their higher proliferative ability upon antigen re-encounter. Defining a mechanism to enhance TCM cells and delay terminal differentiation of CD8 + T cells is crucial for cancer immune therapy, as it can promote a better tumor immune response. The differentiation of CD8 + memory T cells is thought to be coordinated by the phosphoinositide 3-kinase (PI3K)/Akt pathway. We, therefore, investigated the role of Akt isoforms in the differentiation and proliferation of memory CD8 + T cells. We found that Akt1 and Akt2, but not Akt3, drive the terminal differentiation of CD8 + T cells, and their inhibition enhances the therapeutically superior TCM phenotype. Furthermore, the inhibition of Akt1 and Akt2, but not Akt 3, delays CD8 + T-cell exhaustion and preserves naïve and TCM CD8 + T cells, thus enhancing their proliferative ability and survival and prolonging their cytokine and Granzyme B production ability. Here, we define a mechanism in which proliferative potential, function, and survival of CD8 + T cells are enhanced by maintaining a reservoir of TCM and naïve cells using only Akt1 and Akt2 inhibition. Therefore, our findings strongly suggest the utility of using Akt1 and Akt2 inhibitors to modulate CD8 + T cells, both for adoptive cell transfer and vaccine-based cancer immune therapies.
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BACKGROUND: The protein products of the early genes E6 and E7 in high-risk HPV types 16 and 18 have been implicated in the oncogenic capability of these viruses. Therefore, these peptides represent attractive vaccine therapy targets. METHODS: Thirty-two patients with advanced cervical cancer (HPV16 or 18 positive) were treated with HPV16 E6 (18-26) (Arm A) or HPV16 E7 (12-20) peptide (Arm B) pulsed on PBMCs in order to illicit immune response against the relevant peptide on both arms. These PBMCs were cultured for a short time (48 hours only) and in the presence of GM- CSF, accordingly, they were identified as "Pre-Immature Dentritic Cells". RESULTS: 51Cr release assay and ELISPOT demonstrated evidence of specific immune response against the relevant peptide in 10/16 (63%) evaluable patients in arm A and 7/12 (58%) in arm B. HPV16 E6 was found to be homologous to HPV18 E6 in both vivo and vitro. The median overall survival (OS) and progression free survival (PFS) for the full cohort was 10.0 and 3.5 months, respectively. There were no RECIST responses in any patient. The majority of toxicities were grade I and II. CONCLUSIONS: We demonstrated the feasibility and ability of Pre-Immature Dentritic Cells pulsed with HPV16 E6 (18-26) or HPV16 E7 (12-20) to induce a specific immune response against the relevant peptide despite the advanced disease of the cervical cancer patients treated on this trial. We believe that this observation deserves further investigations.
Asunto(s)
Vacunas contra el Cáncer/uso terapéutico , Células Dendríticas/inmunología , Proteínas Oncogénicas Virales/administración & dosificación , Proteínas E7 de Papillomavirus/administración & dosificación , Proteínas Represoras/administración & dosificación , Neoplasias del Cuello Uterino/terapia , Adulto , Vacunas contra el Cáncer/inmunología , Femenino , Humanos , Persona de Mediana Edad , Proteínas Oncogénicas Virales/inmunología , Proteínas E7 de Papillomavirus/inmunología , Proteínas Represoras/inmunología , Neoplasias del Cuello Uterino/inmunologíaRESUMEN
Despite the strides that immunotherapy has made in mediating tumor regression, the clinical effects are often transient, and therefore more durable responses are still needed. The temporary nature of the therapy-induced immune response can be attributed to tumor immune evasion mechanisms, mainly the effect of suppressive immune cells and, in particular, regulatory T cells (Treg). Although the depletion of Tregs has been shown to be effective in enhancing immune responses, selective depletion of these suppressive cells without affecting other immune cells has not been very successful, and new agents are sought. We found that PI3K-Akt pathway inhibitors selectively inhibit Tregs with minimal effect on conventional T cells (Tconv). Our results clearly show selective in vitro inhibition of activation (as represented by a decrease in downstream signaling) and proliferation of Tregs in comparison with Tconvs when treated with different Akt and PI3K inhibitors. This effect has been observed in both human and murine CD4 T cells. In vivo treatment with these inhibitors resulted in a significant and selective reduction in Tregs in both naïve and tumor-bearing mice. Furthermore, these PI3K-Akt inhibitors led to a significant therapeutic antitumor effect, which was shown to be Treg dependent. Here, we report the use of PI3K-Akt pathway inhibitors as potent agents for the selective depletion of suppressive Tregs. We show that these inhibitors are able to enhance the antitumor immune response and are therefore promising clinical reagents for Treg depletion.
Asunto(s)
Activación de Linfocitos/inmunología , Fosfatidilinositol 3-Quinasas/inmunología , Proteínas Proto-Oncogénicas c-akt/inmunología , Transducción de Señal/inmunología , Linfocitos T Reguladores/inmunología , Animales , Femenino , Citometría de Flujo , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BLRESUMEN
BACKGROUND: One of the significant tumor immune escape mechanisms and substantial barrier for successful immunotherapy is tumor-mediated inhibition of immune response through cell-to-cell or receptor/ligand interactions. Programmed death receptor-1 (PD-1) interaction with its ligands, PD-L1 and PD-L2, is one of the important strategies that many tumors employ to escape immune surveillance. Upon PD-Ls binding to PD-1, T cell receptor (TCR) signaling is dampened, causing inhibition of proliferation, decreased cytokine production, anergy and/or apoptosis. Thus PD-Ls expression by tumor cells serves as a protective mechanism, leading to suppression of tumor-infiltrating lymphocytes in the tumor microenvironment. Lm-LLO immunotherapies have been shown to be therapeutically effective due to their ability to induce potent antigen-specific immune responses. However, it has been demonstrated that infection with Lm leads to up-regulation of PD-L1 on mouse immune cells that can inhibit effector T cells through PD-1/PD-L1 pathway. METHODS: Therapeutic and immune efficacy of Listeria-based vaccine (Lm-LLO-E7) in combination with anti-PD-1 antibody was tested in E7 antigen expressing TC-1 mouse tumor model. Tumor growth, survival, as well as peripheral and tumor-infiltrating immune cell profiles after immunotherapy were assessed. RESULTS: Here we demonstrate that the combination of an Lm-LLO immunotherapy with anti-PD-1 antibody that blocks PD-1/PD-L1 interaction, significantly improves immune and therapeutic efficacy of treatment in TC-1 mouse tumor model. Importantly, we show that in addition to significant reduction of regulatory T cells (Treg) and myeloid-derived suppressor cells (MDSC) in both spleen and tumor microenvironment that are mediated solely by the Lm-LLO immunotherapy, the addition of anti-PD-1 antibody to the treatment results in significant increase of antigen-specific immune responses in periphery and CD8 T cell infiltration into the tumor. As a result, this combinational treatment leads to significant inhibition of tumor growth and prolonged survival/complete regression of tumors in treated animals. We also demonstrate that in vitro infection with Lm results in significant upregulation of surface PD-L1 expression on human monocyte-derived dendritic cells suggesting the translational capacity of this finding. CONCLUSIONS: Our findings demonstrate that combination of Lm-LLO-based vaccine with blocking of PD-1/PD-L1 interaction is a feasible approach with clinical translation potential that can lead to overall enhancement of the efficacy of anti-tumor immunotherapy.