Tumor-Specific Cytotoxic T Cells Are Crucial for Efficacy of Immunomodulatory Antibodies in Patients with Lung Cancer

In vitro and in vivo antitumor effects of 50 to 100-KDa components from B16 melanoma culture supernatant

The development of immunological therapies for melanoma has been of considerable concern in recent years. Whole tumor cell lysates have been used to develop antitumor vaccines, but the effective components of the lysates have not been identified. In the present study, protein elements were purified from the B16 supernatant to analyze the in vitro chemotaxis towards mouse spleen lymphocytes using a Boyden chamber. Prior to establishing a B16 melanoma model, C57BL/6 mice were vaccinated with these proteins, and melanoma growth, tumor appearance time and behavioral changes were observed. Next, the cytotoxicity and subsets of the tumor infiltrating lymphocytes, and the histological characteristics of the melanoma were analyzed. The isolated purified fragments of B16 melanoma culture supernatant had strong antitumor effects. The possible antitumor mechanism was delineated, and was identified to possibly be through the activation of cluster of differentiation 8-positive T cells and the promotion of B16 cell differentiation. These methods will provide a novel insight into understanding antitumor immunological mechanisms and provide a potential avenue for immunotherapy.

The role of the immune system in non-small cell lung carcinoma and potential for therapeutic intervention

Over a hundred years after the first description of this disease, lung cancer represents one of the major challenges in oncology. Radical treatment cannot be introduced in more than 70% of cases and overall survival rate does not exceed 15%. The immunosurveillance of lung cancer may be effective in early oncogenesis but is inhibited in the course of developing a clinically detectable tumor. Very low and heterogonous antigenicity of lung cancer cells leads to passive escape from anti-cancer immune defense. The cytotoxic lymphocytes (CTLs) that play a main role in the anticancer response are actively suppressed in the tumor environment and following regulatory mechanisms inhibit the recognition of tumor antigens by antigen presenting cells. The population of regulatory T cells (Tregs) is augmented and the expression of transcription factor-Foxp3 is markedly increased on tumor cells and tumor infiltrating lymphocytes (TIL). It is accomplished by M2 macrophage polarization, the activity of myeloid derived suppressor cells (MDSCs) and a significantly elevated concentration of cytokines: transforming growth factor beta (TGFβ) and IL-10 in the tumor microenvironment. Very active suppression of immune protection is the predominant role of the programmed death 1 (PD-1)-PD-L1 pathway. The blockage of this pathway was found to be an effective treatment approach; therefore the monoclonal antibodies are being intensively investigated in lung cancer patients. Cytotoxic T lymphocyte antigen-4 (CTLA-4) is the molecule capable of inhibiting the activation signal. The antibody anti-CTLA-4 improves CTLs function in solid tumors and lung cancer patients may benefit from use of this agent. The second way in lung cancer immunotherapy is production of anti-cancer vaccines using recognized cancer antigens: MAGE-A3, membrane associated glycoprotein (MUC-1), and EGF. It was recently shown in ongoing clinical trials that combined therapies: immune- and chemotherapy, radiotherapy or targeted therapy seem to be effective. Immunotherapy in lung cancer has an individual character-there is a need to assess the patient's immune status prior to implementation of immunomodulating therapy.

Mechanisms of immune response regulation in lung cancer

Lung cancer is a leading cause of cancer deaths. As a solid tumor with low antigenicity and heterogenic phenotype lung cancer evades host immune defense. The cytotoxic anticancer effect is suppressed by a complex mechanism in tumor microenvironment. The population of regulatory T cells (Tregs) plays a crucial role in this inhibition of immune response. Tregs are defined by presence of forkhead box P3 (Foxp3) molecule. The high expression of Foxp3 was found in lung cancer cells and in tumor infiltrating lymphocytes (TIL). Cytotoxic T-lymphocyte antigen 4 (CTLA4) is constitutively expressed on Tregs and suppresses T cell activation. The elevated CTLA4 expression in lymphocytes in patients with lung cancer was found. Recently the antibodies blocking CTLA4 showed some clinical efficacy in patients with lung cancer. Cancer cells and immune cells release many cytokines capable to show suppressive immune effect in cancer microenvironment. The most active are transforming growth factorβ (TGFβ) and IL-10. The pleiotropic function of Th17 population is TGFβ related. The myeloid lineage of suppressor cells in lung cancer is represented by tumor associated macrophages (TAM) with phenotype of M2 macrophages and some regulatory properties with releasing amounts of IL-10 and TGFβ. The myeloid derived suppressor cells (MDSCs) control cytotoxic T cell activity in mechanisms which are highly dependent on the context of tumor environment. The mechanisms of anticancer immune response regulation need further investigation as an important target to new way of treatment.

Immunotherapy prospects in the treatment of lung cancer and mesothelioma

A very recent finding is the role of immune activation in cancer. The assumption that stimulating the patient's immune system to attack tumors is a valuable treatment option in malignant diseases has gained more acceptance. However the high immunosuppressive effects caused by the tumor limits this beneficial effect. There is a delicate balance between immunoactivation and immunosuppression in a patient. Especially in non small cell lung cancer (NSCLC), the role of immunosuppressive cells hampering immune activation is high. But also in small cell lung cancer (SCLC) and mesothelioma immunosuppressive activity is high. This is suggested to be related to the type of tumor, advanced stage of the disease, and the tumor load. In this review, we provide an overview of the progress and challenges in the immunotherapeutic approaches in lung cancer. We conclude with the concept that immunotherapy in thoracic malignancies must be tailored made to the balance of the immune system.

Presence of circulating Her2-reactive CD8 + T-cells is associated with lower frequencies of myeloid-derived suppressor cells and regulatory T cells, and better survival in older breast cancer patients

Introduction

Breast cancer is one of the most common cancers among women. Its incidence is increasing in many countries and a higher number of older women are now being diagnosed with the disease. Immune parameters are implicated in disease progression, and the frequencies of both myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs), associated with tumour burden, have been suggested to be indicators of poor prognosis in cases of metastatic breast cancer.

Methods

Here, we have assessed the frequency of peripheral Tregs and MDSCs in relation to in vitro T cell responses to Her2 antigen in 40 untreated breast cancer patients 65 to 87 years of age at diagnosis.

Results

The five-year survival rate of patients who mounted a CD8+ T cell response to Her2 peptides and had a lower frequency of Lin⁻CD14⁺HLA-DR⁻MDSCs was 100% compared to only 38% in patients without Her2-reactive CD8+ T cells and with higher frequencies of MDSCs (P = 0.03). Patients who lacked a CD8 response to Her2 tended to have higher frequencies of MDSCs. Similarly, patients who lacked a CD8 response to Her2 and had higher frequencies of CD4⁺Foxp3⁺CD127^lowCD25⁺ Tregs had only 50% survival compared to the 100% survival of patients who did mount a CD8 response and had lower frequencies of Tregs (P = 0.03). A similar trend was observed for activated (CD4⁺CD45RA⁻Foxp3^hi) but not resting Tregs (CD4⁺CD45RA⁺FoxP3⁺). This survival advantage was observed in both metastatic and non-metastatic patients.

Conclusions

Our data demonstrate a negative role of both MDSCs and Tregs in the prognosis of breast cancer patients, the mechanism of which might be through dampening favourable CD8+ T cell immune responses to tumour-associated antigens.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-015-0541-z) contains supplementary material, which is available to authorized users.

Cryptotanshinone induces inhibition of breast tumor growth by cytotoxic CD4+ T cells through the JAK2/STAT4/ perforin pathway

Cryptotanshinone (CPT), is a quinoid diterpene isolated from the root of the Asian medicinal plant, Salvia miotiorrhiza bunge. Numerous researchers have found that it could work as a potent antitumor agent to inhibit tumor growth in vitro, buith there has been much less emphasis on its in vivo role against breast tumors. Using a mouse tumor model of MCF7 cells, we showed that CPT strongly inhibited MCF7 cell growth in vivo with polarization of immune reactions toward Th1-type responses, stimulation of naive CD4+ T cell proliferation, and also increased IFN-γ and perforin production of CD4+ T cells in response to tumor-activated splenocytes. Furthermore, data revealed that the cytotoxic activity of CD4+ T cells induced by CPT was markedly abrogated by concanamycin A(CMA), a perforin inhibitor, but not IFN-γ Ab. On the other hand, after depletion of CD4+ T cells or blocked perforin with CMA in a tumor-bearing model, CPT could not effectively suppress tumor growth, but this phenomenon could be reversed by injecting naive CD4+ T cells. Thus, our results suggested that CPT mainly inhibited breast tumor growth through inducing cytotoxic CD4+ T cells to secrete perforin. We further found that CPT enhanced perforin production of CD4+ T cells by up-regulating JAK2 and STAT4 phosphorylation. These findings suggest a novel potential therapeutic role for CPT in tumor therapy, and demonstrate that CPT performs its antitumor functions through cytotoxic CD4+ T cells.

Emerging drugs for squamous cell lung cancer

INTRODUCTION

The management of advanced NSCLC has been shifted by histology-driven treatment and molecularly targeted therapy, especially in lung adenocarcinoma. However, as the second most common histology in NSCLC, the treatment options for squamous cell lung cancer (SQCLC) remain very limited.

AREAS COVERED

The review first discusses the role of histology in management of NSCLC and new cytotoxic agents in SQCLC, and then addresses genomic characterization and potential molecular targets in SQCLC. The article then provides an overview for several major categories of novel molecularly targeted therapies and immune-based strategies with particular attention to ongoing SQCLC trials.

EXPERT OPINION

The key challenges in drug development are to uncover novel actionable targets and to identify predictive biomarkers. Progress in genomic analysis has identified some promising targetable genes and oncogenic pathways in SQCLC with a wave of targeted agents being tested in clinical trials. Immunotherapy has also raised great interest in management of SQCLC, especially agents targeting immune check points, cytotoxic T-lymphocyte antigen-4, programmed death-1 receptor and its ligands. Better understanding of tumor biology and development of novel targeted therapies will help to facilitate more effective personalized therapy for patients with this devastating illness.

Cellular and molecular immunology of lung cancer: therapeutic implications

Although the incidence of lung cancer is declining, the prognosis remains poor. This is likely due to lack of early detection and only recent developments in selective cancer therapies. Key immune cells involved in the pathogenesis of lung cancer include CD4(+) T lymphocytes, macrophages, dendritic cells and NK cells. The growing understanding of these cells indicates a highly complex and intertwined network of their involvement in each stage of lung cancer. Immune cell types and numbers affect prognosis and could offer an opportunity for clinical therapeutic applications. However, an incomplete understanding of immune cell involvement and the underlying processes in lung cancer still remain. Deeper investigation focusing on the role of the immune cells will further the understanding of lung carcinogenesis and develop novel therapeutic approaches for the treatment and management of patients with more specialized and selective lung cancer.

The tumor immune microenvironment in octogenarians with stage I non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related mortality and has increasingly become a disease of elderly patients. Elderly patients are underrepresented in clinical trials that evaluate treatments for NSCLC. It has been suggested that patients >65 years of age have less robust immune responses to infections, immunizations, and tumors compared with younger patients. With increasing focus and number of immunotherapy clinical trials for NSCLC, we investigated the relationship between patient age and the tumor immune microenvironment in NSCLC. Using tissue microarrays from 1,278 patients with surgically resected Stage I NSCLC (≤65 years [33%], 66-79 years [55%], and ≥80 years [12%]), we determined whether quantitative and qualitative immune cell infiltration in the tumor differed between younger and older patients. Furthermore, we investigated the prognostic value of immune cell infiltration with respect to recurrence in octogenarians. We found that there were no statistically significant differences between older and younger patients in tumoral immune infiltration or effector regulatory immune response ratios (FoxP3/CD3, FoxP3/CD4, and FoxP3/CD8 ratios). In octogenarians, presence of low tumoral CD68+ immune cells was an independent predictor of recurrence. In the uniform cohort of surgically selected and resected Stage I NSCLC patients, tumor immune cell infiltration among the older age group resembled other age groups. Our study provides information that supports inclusion of older age patients selected for surgical resection in neoadjuvant or adjuvant immunotherapy clinical trials for lung cancer.

Effectiveness and safety of chemotherapy combined with dendritic cells co-cultured with cytokine-induced killer cells in the treatment of advanced non-small-cell lung cancer: a systematic review and meta-analysis

Background

Lung cancer, particularly non-small-cell lung cancer (NSCLC) is the leading cause of cancer mortality. Chemotherapy combined dendritic cells co-cultured with cytokine-induced killer cells (DC-CIK) immunotherapy has been applied in advanced NSCLC patients' treatment, but couldn't provide consistent beneficial results. Therefore, it is necessary to evaluate the efficiency and safety of combination therapy to promote the application.

Methods

A literature search for randomized controlled trials of NSCLC was conducted in PubMed database. Before meta-analysis was performed, studies were evaluated heterogeneity. Pooled risk ratios (RRs) were estimated and 95% confidence intervals (CIs) were calculated using a fixed-effect model. Sensitivity analysis was also performed.

Results

Six eligible trials were enrolled. Efficiency and safety of chemotherapy followed by DC-CIK immunotherapy (experimental group) and chemotherapy alone (control group) were compared. 1-year overall survival (OS) (P = 0.02) and progression free survival (PFS) (P = 0.005) in the experimental group were significantly increased compared with the control. Disease control rate (DCR) (P = 0.006) rose significantly in experimental group. However, no significant differences between the two groups were observed in 2-year OS (P = 0.21), 2-year PFS (P = 0.10), overall response rate (ORR) (P = 0.76) and partial response (PR) (P = 0.22). Temporary fever, anemia, leukopenia and nausea were the four major adverse events (AEs) treated by chemotherapy. The incidence of anemia, leukopenia and nausea in the experimental group was obviously lower than the control group. Temporary fever rate was higher in experimental group than that in the control, but could be alleviated by taking sufficient rest.

Conclusions

Chemotherapy combined with DC-CIK immunotherapy showed superiority in DCR, 1-year OS and PFS, and no more AEs appeared, however, there was no significant improvement in ORR, PR, 2-year OS and PFS. As a whole, the combination therapy is safer but modest in efficacy for advanced NSCLC patients.

Targeting programmed cell death ligand 1 in osteosarcoma: an auto-commentary on therapeutic potential

Programmed cell death ligand 1 (PDL1) expression was recently shown to correlate with tumor-infiltrating lymphocytes (TILs) in a subset of osteosarcoma patients. Among clinical factors evaluated across human osteosarcoma samples, a pulmonary origin of metastases correlated with high PDL1 expression and prominent TILs. Considering that multiple agents targeting PD-1/PDL1 are under development, targeting this immune checkpoint may be a novel immunotherapeutic route for osteosarcoma in future clinical trials.

Polarization imaging and classification of Jurkat T and Ramos B cells using a flow cytometer

Label-free and rapid classification of cells can have awide range of applications in biology. We report a robust method of polarization diffraction imaging flow cytometry (p-DIFC) for achieving this goal. Coherently scattered light signals are acquired from single cells excited by a polarized laser beam in the form of two cross-polarized diffraction images. Image texture and intensity parameters are extracted with a gray level co-occurrence matrix (GLCM) algorithm to obtain an optimized set of feature parameters as the morphological "fingerprints" for automated cell classification. We selected the Jurkat T cells and Ramos B cells to test the p-DIFC method's capacity for cell classification. After detailed statistical analysis, we found that the optimized feature vectors yield accuracies of classification between the Jurkat and Ramos ranging from 97.8% to 100% among different cell data sets. Confocal imaging and three-dimensional reconstruction were applied to gain insights on the ability of p-DIFC method for classifying the two cell lines of highly similar morphology. Based on these results we conclude that the p-DIFC method has the capacity to discriminate cells of high similarity in their morphology with "fingerprints" features extracted from the diffraction images, which may be attributed to subtle but statistically significant differences in the nucleus-to-cell volume ratio in the case of Jurkat and Ramos cells.

Molecular pathways and therapeutic targets in lung cancer

Lung cancer is still the leading cause of cancer death worldwide. Both histologically and molecularly lung cancer is heterogeneous. This review summarizes the current knowledge of the pathways involved in the various types of lung cancer with an emphasis on the clinical implications of the increasing number of actionable molecular targets. It describes the major pathways and molecular alterations implicated in the development and progression of non-small cell lung cancer (adenocarcinoma and squamous cancer), and of small cell carcinoma, emphasizing the molecular alterations comprising the specific blueprints in each group. The approved and investigational targeted therapies as well as the immune therapies, and clinical trials exploring the variety of targeted approaches to treatment of lung cancer are the main focus of this review.

Toll-like receptor 9 agonist enhances anti-tumor immunity and inhibits tumor-associated immunosuppressive cells numbers in a mouse cervical cancer model following recombinant lipoprotein therapy

Background

Although cytotoxic T lymphocytes (CTLs) play a major role in eradicating cancer cells during immunotherapy, the cancer-associated immunosuppressive microenvironment often limits the success of such therapies. Therefore, the simultaneous induction of cancer-specific CTLs and reversal of the immunosuppressive tumor microenvironment may be more effectively achieved through a single therapeutic vaccine. A recombinant lipoprotein with intrinsic Toll-like receptor 2 (TLR2) agonist activity containing a mutant form of E7 (E7m) and a bacterial lipid moiety (rlipo-E7m) has been demonstrated to induce robust CTL responses against small tumors. This treatment in combination with other TLR agonists is able to eliminate large tumors.

Methods

Mouse bone marrow-derived dendritic cells (DCs) were employed to determine the synergistic production of pro-inflammatory cytokines upon combination of rlipo-E7m and other TLR agonists. Antigen-specific CTL responses were investigated using immunospots or in vivo cytolytic assays after immunization in mice. Mice bearing various tumor sizes were used to evaluate the anti-tumor effects of the formulation. Specific subpopulations of immunosuppressive cells in the tumor infiltrate were quantitatively determined by flow cytometry.

Results

We demonstrate that a TLR9 agonist (unmethylated CpG oligodeoxynucleotide, CpG ODN) enhances CTL responses and eradicates large tumors when combined with rlipo-E7m. Moreover, combined treatment with rlipo-E7m and CpG ODN effectively increases tumor infiltration by CTLs and reduces the numbers of myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs) and regulatory T cells (Tregs) in the tumor microenvironment.

Conclusion

These findings suggest that the dramatic anti-tumor effects of the recombinant lipoprotein together with CpG ODN may reflect the amplification of CTL responses and the repression of the immunosuppressive environment. This promising approach could be applied for the development of additional therapeutic cancer vaccines.

Myeloid Cell COX-2 deletion reduces mammary tumor growth through enhanced cytotoxic T-lymphocyte function

Cyclooxygenase-2 (COX-2) expression is associated with poor prognosis across a range of human cancers, including breast cancer. The contribution of tumor cell-derived COX-2 to tumorigenesis has been examined in numerous studies; however, the role of stromal-derived COX-2 is ill-defined. Here, we examined how COX-2 in myeloid cells, an immune cell subset that includes macrophages, influences mammary tumor progression. In mice engineered to selectively lack myeloid cell COX-2 [myeloid-COX-2 knockout (KO) mice], spontaneous neu oncogene-induced tumor onset was delayed, tumor burden reduced, and tumor growth slowed compared with wild-type (WT). Similarly, growth of neu-transformed mammary tumor cells as orthotopic tumors in immune competent syngeneic myeloid-COX-2 KO host mice was reduced compared with WT. By flow cytometric analysis, orthotopic myeloid-COX-2 KO tumors had lower tumor-associated macrophage (TAM) infiltration consistent with impaired colony stimulating factor-1-dependent chemotaxis by COX-2 deficient macrophages in vitro. Further, in both spontaneous and orthotopic tumors, COX-2-deficient TAM displayed lower immunosuppressive M2 markers and this was coincident with less suppression of CD8(+) cytotoxic T lymphocytes (CTLs) in myeloid-COX-2 KO tumors. These studies suggest that reduced tumor growth in myeloid-COX-2 KO mice resulted from disruption of M2-like TAM function, thereby enhancing T-cell survival and immune surveillance. Antibody-mediated depletion of CD8(+), but not CD4(+) cells, restored tumor growth in myeloid-COX-2 KO to WT levels, indicating that CD8(+) CTLs are dominant antitumor effectors in myeloid-COX-2 KO mice. Our studies suggest that inhibition of myeloid cell COX-2 can potentiate CTL-mediated tumor cytotoxicity and may provide a novel therapeutic approach in breast cancer therapy.

Immunotherapy and lung cancer: current developments and novel targeted therapies

Non-small-cell lung cancer (NSCLC) is a highly prevalent and aggressive disease. In the metastatic setting, major advances include the incorporation of immunotherapy and targeted therapies into the clinician's therapeutic armamentarium. Standard chemotherapeutic regimens have long been reported to interfere with the immune response to the tumor; conversely, antitumor immunity may add to the effects of those therapies. The aim of immunotherapy is to specifically enhance the immune response directed to the tumor. Recently, many trials addressed the role of such therapies for metastatic NSCLC treatment: ipilimumab, tremelimumab, nivolumab and lambrolizumab are immunotherapeutic agents of main interest in this field. In addition, anti-tumor vaccines, such as MAGE-A3, Tecetomide, TG4010, CIMAvax, ganglioside vaccines, tumor cell vaccines and dendritic cell vaccines, emerged as potent inducers of immune response against the tumor. The current work aims to address the most recent developments regarding these innovative immunotherapies and their implementation in the treatment of metastatic NSCLC.

Optimizing the immune system to achieve control of the metastatic malignant lesion

In a recent issue of Nature, an article appeared discussing the issue of "Sizing up a slow assault on Cancer" (Nature 2013;496:14-15). This article attempted to clarify various approaches that the clinician might employ in bringing cancer under control. It also discussed the role of the immune system with regard to its capability for controlling tumor growth. In addition, it covered possible directions that might be taken to improve present responses to immunotherapy based on utilizing T-cell activity directed against the tumor. While there is some validity to the concept that cell mediated immunity is utilized by the host in its attempt to control evolving malignancy, this process actually represents only a minor role taken by the hosts immune system to accomplish what is needed for tumor control. Clinical studies at Precision Biologics have demonstrated that for tumor growth to be effected properly by the hosts immune system, expression of a specific humoral IgG1 response directed against immunogenic tumor glycoproteins on the cell surface membrane, constitutes the primary method needed for tumor control. Failure to obtain significant levels of the needed IgG response almost invariably results in recurrence and progression of disease.

Immunological profiling as a means to invigorate personalized cancer therapy

Immunotherapy has taken off but has not yet reached its cruising altitude and is certainly far from its final destination. Identifying the unique immunological profile of individual cancer patients will provide critical clues for the design of optimal strategies that rectify tumor-induced immune imbalances.