Intratumoral delivery of tumor antigen-loaded DC and tumor-primed CD4+ T cells combined with agonist α-GITR mAb promotes durable CD8+ T-cell-dependent antitumor immunity

Magnesium-related gene ITGAL: a key immunotherapy predictor and prognostic biomarker in pan-cancer

Background

Integrin subunit alpha L (ITGAL) is crucial for activating CD8+ T cells through magnesium-mediated immune synapse formation and specific cytotoxicity. ITGAL might exert an important function in the growth and transformation of cancer.

Methods

Our study comprehensively analyzed ITGAL expression across various cancers, validated by Immunochemistry (IHC) in the laboratory. ITGAL showed prognostic significance in pan-cancer patients, correlated with clinical features, and associated with specific signaling pathways. We also observed a relationship between ITGAL and immune cell infiltration. In HNSCC, ITGAL demonstrated prognostic value and potential implications for immunotherapy response and novel drug targets.

Results

ITGAL expression linked to tumor prognosis across 27 cancers. Elevated ITGAL correlated with good prognosis in CESC, LUAD, SARC, HNSCC, and SKCM. ITGAL involved in immune regulation pathways and showed positive correlation with immune cell infiltration. ITGAL associated with CD8+ T cell infiltration. And high ITGAL expression in CD8+ T cells and NK cells. In HNSCC, ITGAL linked to favorable prognosis and sensitivity to immunotherapy. Predicted potential drugs for HNSCC.

Conclusion

ITGAL is remarkably associated with CD8+T cells and crucial in the tumor immune microenvironment of pan-cancer. Furthermore, our findings may provide a targeted anti-tumor strategy for ITGAL by influencing the tumor immune microenvironment.

Clinical Research on the Mechanisms Underlying Immune Checkpoints and Tumor Metastasis

This study highlights aspects of the latest clinical research conducted on the relationship between immune checkpoints and tumor metastasis. The overview of each immune checkpoint is divided into the following three sections: 1) structure and expression; 2) immune mechanism related to tumor metastasis; and 3) clinical research related to tumor metastasis. This review expands on the immunological mechanisms of 17 immune checkpoints, including TIM-3, CD47, and OX-40L, that mediate tumor metastasis; evidence shows that most of these immune checkpoints are expressed on the surface of T cells, which mainly exert immunomodulatory effects. Additionally, we have summarized the roles of these immune checkpoints in the diagnosis and treatment of metastatic tumors, as these checkpoints are considered common predictors of metastasis in various cancers such as prostate cancer, non-Hodgkin lymphoma, and melanoma. Moreover, certain immune checkpoints can be used in synergy with PD-1 and CTLA-4, along with the implementation of combination therapies such as LIGHT-VTR and anti-PD-1 antibodies. Presently, most monoclonal antibodies generated against immune checkpoints are under investigation as part of ongoing preclinical or clinical trials conducted to evaluate their efficacy and safety to establish a better combination treatment strategy; however, no significant progress has been made regarding monoclonal antibody targeting of CD28, VISTA, or VTCN1. The application of immune checkpoint inhibitors in early stage tumors to prevent tumor metastasis warrants further evidence; the immune-related adverse events should be considered before combination therapy. This review aims to elucidate the mechanisms of immune checkpoint and the clinical progress on their use in metastatic tumors reported over the last 5 years, which may provide insights into the development of novel therapeutic strategies that will assist with the utilization of various immune checkpoint inhibitors.

Skin immunization for effective treatment of multifocal melanoma refractory to PD1 blockade and Braf inhibitors

BACKGROUND

Despite the remarkable benefits associated with the interventional treatment of melanomas (and other solid cancers) with immune checkpoint and Braf inhibitors (Brafi), most patients ultimately progress on therapy. The presence of multifocal/disseminated disease in patients increases their mortality risk. Hence, the development of novel strategies to effectively treat patients with melanomas that are resistant to anti-PD1 mAb (αPD1) and/or Brafi, particularly those with multifocal/disseminated disease remains a major unmet clinical need.

METHODS

Mice developing induced/spontaneous BrafV600E/Pten-/- melanomas were treated by cutaneous immunization with a DNA vaccine encoding the melanoma-associated antigen TRP2, with Brafi or αPD1 alone, or with a combination of these treatments. Tumor progression, tumor-infiltration by CD4+ and CD8+ T cells, and the development of TRP2-specific CD8+ T cells were then monitored over time.

RESULTS

Vaccination led to durable antitumor immunity against PD1/Brafi-resistant melanomas in both single lesion and multifocal disease models, and it sensitized PD1-resistant melanomas to salvage therapy with αPD1. The therapeutic efficacy of the vaccine was associated with host skin-resident cells, the induction of a systemic, broadly reactive IFNγ+CD8+ T cell repertoire, increased frequencies of CD8+ TIL and reduced levels of PD1hi/intCD8+ T cells. Extended survival was associated with improved TIL functionality, exemplified by the presence of enhanced levels of IFNγ+CD8+ TIL and IL2+CD4+ TIL.

CONCLUSIONS

These data support the use of a novel genetic vaccine for the effective treatment of localized or multifocal melanoma refractory to conventional αPD1-based and/or Brafi-based (immune)therapy.

Novel HLA-A2 restricted antigenic peptide derivatives with high affinity for the treatment of breast cancer expressing NY-ESO-1

Tumor immunotherapy based on specific tumor antigen has become the focus for breast cancer, and research into cancer/testes antigens (CTA) is progressing. As an important member in the CTA, NY-ESO-1 plays a crucial role in the treatment and prognosis of breast cancer. In this study, we aimed to improve the binding ability to MHC by designing and synthesizing stable NY-ESO-1-derived peptides, based on NetMHC 4.0 webserver (http://www.cbs.dtu.dk/services/NetMHC/) and HLP webserver (http://crdd.osdd.net/raghava/hlp/pep_both.htm). Moreover, after modification of the lead compound, affinity of the peptides to human leukocyte antigen-A2 (HLA-A2) was determined by a flow cytometry and an inverted fluorescence microscope in T2 cells that show high expression of HLA-A2. The results demonstrated that the affinity of peptides II-4 and II-10 to HLA-A2 was significantly better when compared to others (II-Lead, II-1 ~ II-3, II-5 ~ II-9, II-11 ~ II-15). Further studies indicated that II-4 and II-10, especially II-4, significantly promoted the maturation of HLA-A2-positive human peripheral blood-derived dendritic cells (DCs) from morphology and surface markers, the activation of CD8 + T lymphocytes, and the type-specific killing effect on HLA-A2⁺/NY-ESO-1⁺ MDA-MB-231 cells. Molecular docking studies suggested a strong interaction between peptide II-4 and HLA-A2, thereby indicating that the II-4 is a promising candidate with antigenic potential in the field of immunotherapy that needs more studies.

New directions in chimeric antigen receptor T cell [CAR-T] therapy and related flow cytometry

Chimeric antigen receptor (CAR) T cells provide a promising approach to the treatment of hematologic malignancies and solid tumors. Flow cytometry is a powerful analytical modality, which plays an expanding role in all stages of CAR T therapy, from lymphocyte collection, to CAR T cell manufacturing, to in vivo monitoring of the infused cells and evaluation of their function in the tumor environment. Therefore, a thorough understanding of the new directions is important for designing and implementing CAR T-related flow cytometry assays in the clinical and investigational settings. However, the speed of new discoveries and the multitude of clinical and preclinical trials make it challenging to keep up to date in this complex field. In this review, we summarize the current state of CAR T therapy, highlight the areas of emergent research, discuss applications of flow cytometry in modern cell therapy, and touch upon several considerations particular to CAR detection and assessing the effectiveness of CAR T therapy.

GITR Agonism Triggers Antitumor Immune Responses through IL21-Expressing Follicular Helper T Cells

Although treatment with the glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR) agonistic antibody (DTA-1) has shown antitumor activity in various tumor models, the underlying mechanism is not fully understood. Here, we demonstrate that interleukin (IL)-21-producing follicular helper T (Tfh) cells play a crucial role in DTA-1-induced tumor inhibition. The administration of DTA-1 increased IL21 expression by Tfh cells in an antigen-specific manner, and this activation led to enhanced antitumor cytotoxic T lymphocyte (CTL) activity. Mice treated with an antibody that neutralizes the IL21 receptor exhibited decreased antitumor activity when treated with DTA-1. Tumor growth inhibition by DTA-1 was abrogated in Bcl6 ^fl/fl Cd4 ^Cre mice, which are genetically deficient in Tfh cells. IL4 was required for optimal induction of IL21-expressing Tfh cells by GITR costimulation, and c-Maf mediated this pathway. Thus, our findings identify GITR costimulation as an inducer of IL21-expressing Tfh cells and provide a mechanism for the antitumor activity of GITR agonism.

Peritumoral administration of DRibbles-pulsed antigen-presenting cells enhances the antitumor efficacy of anti-GITR and anti-PD-1 antibodies via an antigen presenting independent mechanism

Background

TNF receptor family agonists and checkpoint blockade combination therapies lead to minimal tumor clearance of poorly immunogenic tumors. Therefore, a need to enhance the efficacy of this combination therapy arises. Antigen-presenting cells (APCs) present antigen to T cells and steer the immune response through chemokine and cytokine secretion. DRibbles (DR) are tumor-derived autophagosomes containing tumor antigens and innate inflammatory adjuvants.

Methods

Using preclinical murine lung and pancreatic cancer models, we assessed the triple combination therapy of GITR agonist and PD-1 blocking antibodies with peritumoral injections of DRibbles-pulsed-bone marrow cells (BMCs), which consisted mainly of APCs, or CD103+ cross-presenting dendritic cells (DCs). Immune responses were assessed by flow cytometry. FTY720 was used to prevent T-cell egress from lymph nodes to assess lymph node involvement, and MHC-mismatched-BMCs were used to assess the necessity of antigen presentation by the peritumorally-injected DR-APCs.

Results

Tritherapy increased survival and cures in tumor-bearing mice compared to combined antibody therapy or peritumoral DR-BMCs alone. Peritumorally-injected BMCs remained within the tumor for at least 14 days and tritherapy efficacy was dependent on both CD4+ and CD8+ T cells. Although the overall percent of tumor-infiltrating T cells remained similar, tritherapy increased the ratio of effector CD4+ T cells-to-regulatory T cells, CD4+ T-cell cytokine production and proliferation, and CD8+ T-cell cytolytic activity in the tumor. Despite tritherapy-induced T-cell activation and cytolytic activity in lymph nodes, this T-cell activation was not required for tumor regression and enhanced survival. Replacement of DR-BMCs with DR-pulsed-DCs in the tritherapy led to similar antitumor effects, whereas replacement with DRibbles was less effective but delayed tumor growth. Interestingly, peritumoral administration of DR-pulsed MHC-mismatched-APCs in the tritherapy led to similar antitumor effects as MHC-matched-APCs, indicating that the observed enhanced antitumor effect was mediated independently of antigen presentation by the administered APCs.

Conclusions

Overall, these results demonstrate that peritumoral DR-pulsed-BMC/DC administration synergizes with GITR agonist and PD-1 blockade to locally modulate and sustain tumor effector T-cell responses independently of T cell priming and perhaps through innate inflammatory modulations mediated by the DRibbles adjuvant. We offer a unique approach to modify the tumor microenvironment to benefit T-cell-targeted immunotherapies.

Trial watch: dendritic cell vaccination for cancer immunotherapy

Dendritic- cells (DCs) have received considerable attention as potential targets for the development of anticancer vaccines. DC-based anticancer vaccination relies on patient-derived DCs pulsed with a source of tumor-associated antigens (TAAs) in the context of standardized maturation-cocktails, followed by their reinfusion. Extensive evidence has confirmed that DC-based vaccines can generate TAA-specific, cytotoxic T cells. Nonetheless, clinical efficacy of DC-based vaccines remains suboptimal, reflecting the widespread immunosuppression within tumors. Thus, clinical interest is being refocused on DC-based vaccines as combinatorial partners for T cell-targeting immunotherapies. Here, we summarize the most recent preclinical/clinical development of anticancer DC vaccination and discuss future perspectives for DC-based vaccines in immuno-oncology.

Impact of combination immunochemotherapies on progression of 4NQO-induced murine oral squamous cell carcinoma

Advanced oral squamous cell carcinomas (OSCC) have limited therapeutic options. Although immune therapies are emerging as a potentially effective alternative or adjunct to chemotherapies, the therapeutic efficacy of combination immune chemotherapies has yet to be determined. Using a 4-nitroquinolone-N-oxide (4NQO) orthotopic model of OSCC in immunocompetent mice, we evaluated the therapeutic efficacy of single- and combined-agent treatment with a poly-epitope tumor peptide vaccine, cisplatin and/or an A2AR inhibitor, ZM241385. The monotherapies or their combinations resulted in a partial inhibition of tumor growth and, in some cases, a significant but transient upregulation of systemic anti-tumor CD8+ T cell responses. These responses eroded in the face of expanding immunoregulatory cell populations at later stages of tumor progression. Our findings support the need for the further development of combinatorial therapeutic approaches that could more effectively silence dominant immune inhibitory pathways operating in OSCC and provide novel, more beneficial treatment options for this tumor.

Empowering dendritic cell cancer vaccination: the role of combinatorial strategies

Dendritic cells (DCs) are bone marrow-derived immune cells that play a crucial role in inducing the adaptive immunity and supporting the innate immune response independently from T cells. In the last decade, DCs have become a hopeful instrument for cancer vaccines that aims at re-educating the immune system, leading to a potent anti-cancer immune response able to overcome the immunosuppressive tumor microenvironment (TME). Although several studies have indicated that DC-based vaccines are feasible and safe, the clinical advantages of DC vaccination as monotherapy for most of the neoplasms remain a distant target. Recently, many reports and clinical trials have widely used innovative combinatorial therapeutic strategies to normalize the immune function in the TME and synergistically enhance DC function. This review will describe the most relevant and updated evidence of the anti-cancer combinatorial approaches to boost the clinical potency of DC-based vaccines.

Trial Watch: Immunostimulatory monoclonal antibodies for oncological indications

The goal of cancer immunotherapy is to establish new or boost pre-existing anticancer immune responses that eradicate malignant cells while generating immunological memory to prevent disease relapse. Over the past few years, immunomodulatory monoclonal antibodies (mAbs) that block co-inhibitory receptors on immune effectors cells - such as cytotoxic T lymphocyte-associated protein 4 (CTLA4), programmed cell death 1 (PDCD1, best known as PD-1) - or their ligands - such as CD274 (best known as PD-L1) - have proven very successful in this sense. As a consequence, many of such immune checkpoint blockers (ICBs) have already entered the clinical practice for various oncological indications. Considerable attention is currently being attracted by a second group of immunomodulatory mAbs, which are conceived to activate co-stimulatory receptors on immune effector cells. Here, we discuss the mechanisms of action of these immunostimulatory mAbs and summarize recent progress in their preclinical and clinical development.