Direct tumor recognition by a human CD4(+) T-cell subset potently mediates tumor growth inhibition and orchestrates anti-tumor immune responses

Significance of combined preoperative serum Alb and dNLR for diagnosis of pancreatic cancer

AIM

To investigate diagnostic value of preoperative inflammatory biomarkers in pancreatic cancer (PCC).

MATERIALS & METHODS

Preoperative circulating Alb/Fib ratio, neutrophil/lymphocyte ratio (NLR), derived NLR (dNLR), platelet/lymphocyte ratio and lymphocyte/monocyte ratio were detected and calculated in 226 PCC individuals, 232 healthy controls and 142 additional cancer controls. Receiver-operating characteristic curve and area under the curve (AUC) were used to evaluate the diagnostic efficacy of PCC.

RESULTS

Combined circulating dNLR and Alb could effectively improve the diagnosis of PCC (AUC = 0.931), single dNLR could distinguish early-stage PCC and the disease from healthy controls (AUC = 0.895) and additional cancer controls (AUC = 0.794).

CONCLUSION

Circulating dNLR was an effective biomarker for diagnosis and identification of early-stage PCC. Combined dNLR and Alb could improve the diagnostic efficacy of the disease.

Human CD26high T cells elicit tumor immunity against multiple malignancies via enhanced migration and persistence

CD8+ T lymphocytes mediate potent immune responses against tumor, but the role of human CD4+ T cell subsets in cancer immunotherapy remains ill-defined. Herein, we exhibit that CD26 identifies three T helper subsets with distinct immunological properties in both healthy individuals and cancer patients. Although CD26neg T cells possess a regulatory phenotype, CD26int T cells are mainly naive and CD26high T cells appear terminally differentiated and exhausted. Paradoxically, CD26high T cells persist in and regress multiple solid tumors following adoptive cell transfer. Further analysis revealed that CD26high cells have a rich chemokine receptor profile (including CCR2 and CCR5), profound cytotoxicity (Granzyme B and CD107A), resistance to apoptosis (c-KIT and Bcl2), and enhanced stemness (β-catenin and Lef1). These properties license CD26high T cells with a natural capacity to traffic to, regress and survive in solid tumors. Collectively, these findings identify CD4+ T cell subsets with properties critical for improving cancer immunotherapy.

CD74 and intratumoral immune response in breast cancer

CD74 (invariant chain) plays a role in MHC class II antigen presentation. We assessed CD74 and MHCII expression in tumor cells, as well as CD8, CD4, and CD68 tumor infiltrating leucocyte (TIL) density by immunohistochemistry in a cohort of 492 breast cancer patients. CD74 expression was associated with poor prognostic markers including patient age, tumor grade, ER status, non-Luminal A subtypes, and with MHCII expression and higher TIL densities, particularly in the Basal-like subgroup. Univariate analysis showed a favorable prognostic effect of CD74 (Hazard ratio = 0.46, 95% CI = 0.26–0.89, p = 0.022) and for combined CD74/MHCII (Hazard ratio = 0.26, 95% CI = 0.17–0.81, p = 0.014) positive status for overall survival that was only manifested in the Basal-like subgroup. CD74 and MHCII expression is associated with patient survival in Basal-like breast cancer, and the association with TIL may reflect an effective intratumoral immune response.

Vaccines targeting helper T cells for cancer immunotherapy

There are compelling arguments for designing cancer vaccines specifically to induce CD4+ helper T cell responses. Recent studies highlight the crucial role of proliferating, activated effector memory Th1 CD4+ T cells in effective antitumor immunity and reveal that CD4+ T cells induce more durable immune-mediated tumor control than CD8+ T cells. CD4+ T cells promote antitumor immunity by numerous mechanisms including enhancing antigen presentation, co-stimulation, T cell homing, T cell activation, and effector function. These effects are mediated at sites of T cell priming and at the tumor microenvironment. Several cancer vaccine approaches induce durable CD4+ T cell responses and have promising clinical activity. Future work should further optimize vaccine adjuvants and combination therapies incorporating helper peptide vaccines.

Tumor Immunology meets…Immunology: Modified cancer cells as professional APC for priming naïve tumor-specific CD4+ T cells

Although recent therapeutic approaches have revitalized the enthusiasm of the immunological way to combat cancer, still the comprehension of immunity against tumors is largely incomplete. Due to their specific function, CD8+ T cells with cytolytic activity (CTL) have attracted the attention of most investigators because CTL are considered the main effectors against tumor cells. Nevertheless, CTL activity and persistence is largely dependent on the action of CD4+ T helper cells (TH). Thus establishment of tumor-specific TH cell response is key to the optimal response against cancer. Here we describe emerging new strategies to increase the TH cell recognition of tumor antigens. In particular, we review recent data indicating that tumor cells themselves can act as surrogate antigen presenting cells for triggering TH response and how these findings can help in constructing immunotherapeutic protocols for anti-cancer vaccine development.

T cell-intrinsic TLR2 stimulation promotes IL-10 expression and suppressive activity by CD45RbHi T cells

While Toll-like receptors (TLRs) represent one of the best characterized innate immune pathways, evidence suggests that TLRs are not restricted to innate leukocytes and some epithelial cells, but are also expressed in T cells. Specifically, published evidence focusing on FoxP3⁺ regulatory T cells demonstrate that they express functional TLR2, which is already known among the TLR family for its association with immune suppression; however, little is known about the relationship between T cell-intrinsic TLR2 binding and cytokine production, T cell differentiation, or T cell receptor (TCR) stimulation. Here, we demonstrate that TCR and TLR2 co-stimulation provides a T cell-intrinsic signal which generates a dramatic, synergistic cytokine response dominated by IL-10. Importantly, the response was not seen in either CD4⁺CD25⁺ or CD4⁺FoxP3⁺ Tregs, yet resulted in the expansion of a suppressive CD4⁺CD25⁺CD62L^-CD44⁺CD45Rb^hi effector/memory T cell subset not typically associated with immune inhibition. This study reveals the striking ability of a prototypical innate immune receptor to trigger a potent and suppressive IL-10 response in effector/memory T cells, supporting the notion that TLR2 is a co-regulatory receptor on T cells.

A Pilot Study of Stereotactic Body Radiation Therapy Combined with Cytoreductive Nephrectomy for Metastatic Renal Cell Carcinoma

Purpose: While stereotactic body radiotherapy (SBRT) can reduce tumor volumes in patients with metastatic renal cell carcinoma (mRCC), little is known regarding the immunomodulatory effects of high-dose radiation in the tumor microenvironment. The main objectives of this pilot study were to assess the safety and feasibility of nephrectomy following SBRT treatment of patients with mRCC and analyze the immunological impact of high-dose radiation.Experimental Design: Human RCC cell lines were irradiated and evaluated for immunomodulation. In a single-arm feasibility study, patients with mRCC were treated with 15 Gray SBRT at the primary lesion in a single fraction followed 4 weeks later by cytoreductive nephrectomy. RCC specimens were analyzed for tumor-associated antigen (TAA) expression and T-cell infiltration. The trial has reached accrual (ClinicalTrials.gov identifier: NCT01892930).Results: RCC cells treated in vitro with radiation had increased TAA expression compared with untreated tumor cells. Fourteen patients received SBRT followed by surgery, and treatment was well-tolerated. SBRT-treated tumors had increased expression of the immunomodulatory molecule calreticulin and TAA (CA9, 5T4, NY-ESO-1, and MUC-1). Ki67⁺ -proliferating CD8⁺ T cells and FOXP3⁺ cells were increased in SBRT-treated patient specimens in tumors and at the tumor-stromal interface compared with archived patient specimens.Conclusions: It is feasible to perform nephrectomy following SBRT with acceptable toxicity. Following SBRT, patient RCC tumors have increased expression of calreticulin, TAA, as well as a higher percentage of proliferating T cells compared with archived RCC tumors. Collectively, these studies provide evidence of immunomodulation following SBRT in mRCC. Clin Cancer Res; 23(17); 5055-65. ©2017 AACR.

Immune Checkpoint Inhibitors in Lung Cancer - An Unheralded Opportunity?

Lung cancer remains the leading cause of cancer-related death worldwide, with non-small cell lung cancer accounting for 85% of the disease. Over 70% of patients present with locally advanced, non-resectable or metastatic disease and despite improvements in chemoradiotherapy regimens and the development of molecularly targeted agents, 5 year survival rates remain poor, with acquired resistance to novel targeted therapies becoming a growing concern. Currently there remains an unmet need in effectively treating and inducing durable responses in advanced disease. Targeting the immune system has, however, recently given hope of improving therapeutic outcomes for these patients. The notion that the immune system is capable of recognising and eliminating cancer cells is now a widely accepted phenomenon and growing evidence suggests lung cancer is an attractive target for such intervention. Recent success targeting the programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) axis of immune checkpoint inhibition suggests a major immunotherapeutic advance in treating lung cancer and unheralded opportunity for such approaches to further improve outcome for patients. Currently there is considerable interest in combining anti-PD-1 or PD-L1 monoclonal antibodies with established standard of care therapies such as radiotherapy. Radiotherapy is known to be immunostimulatory and efforts are underway to combine and augment the efficacy of the immune checkpoint inhibitors further. This review outlines the interaction between lung cancer and the immune system, summarises current evidence supporting the use of monoclonal antibodies targeting the PD-1 axis in lung cancer and explores the potential of combining radiotherapy with immunotherapy to augment anti-tumour immune responses.

Human leucocyte antigen class I-redirected anti-tumour CD4+ T cells require a higher T cell receptor binding affinity for optimal activity than CD8+ T cells

CD4⁺ T helper cells are a valuable component of the immune response towards cancer. Unfortunately, natural tumour‐specific CD4⁺ T cells occur in low frequency, express relatively low‐affinity T cell receptors (TCRs) and show poor reactivity towards cognate antigen. In addition, the lack of human leucocyte antigen (HLA) class II expression on most cancers dictates that these cells are often unable to respond to tumour cells directly. These deficiencies can be overcome by transducing primary CD4⁺ T cells with tumour‐specific HLA class I‐restricted TCRs prior to adoptive transfer. The lack of help from the co‐receptor CD8 glycoprotein in CD4⁺ cells might result in these cells requiring a different optimal TCR binding affinity. Here we compared primary CD4⁺ and CD8⁺ T cells expressing wild‐type and a range of affinity‐enhanced TCRs specific for the HLA A*0201‐restricted NY‐ESO‐1‐ and gp100 tumour antigens. Our major findings are: (i) redirected primary CD4⁺ T cells expressing TCRs of sufficiently high affinity exhibit a wide range of effector functions, including cytotoxicity, in response to cognate peptide; and (ii) optimal TCR binding affinity is higher in CD4⁺ T cells than CD8⁺ T cells. These results indicate that the CD4⁺ T cell component of current adoptive therapies using TCRs optimized for CD8⁺ T cells is below par and that there is room for substantial improvement.