Suppression of T cell responses in the tumor microenvironment

Metal-based nanoparticle in cancer treatment: lessons learned and challenges

Cancer, being one of the deadliest diseases, poses significant challenges despite the existence of traditional treatment approaches. This has led to a growing demand for innovative pharmaceutical agents that specifically target cancer cells for effective treatment. In recent years, the use of metal nanoparticles (NPs) as a promising alternative to conventional therapies has gained prominence in cancer research. Metal NPs exhibit unique properties that hold tremendous potential for various applications in cancer treatment. Studies have demonstrated that certain metals possess inherent or acquired anticancer capabilities through their surfaces. These properties make metal NPs an attractive focus for therapeutic development. In this review, we will investigate the applicability of several distinct classes of metal NPs for tumor targeting in cancer treatment. These classes may include gold, silver, iron oxide, and other metals with unique properties that can be exploited for therapeutic purposes. Additionally, we will provide a comprehensive summary of the risk factors associated with the therapeutic application of metal NPs. Understanding and addressing these factors will be crucial for successful clinical translation and to mitigate any potential challenges or failures in the translation of metal NP-based therapies. By exploring the therapeutic potential of metal NPs and identifying the associated risk factors, this review aims to contribute to the advancement of cancer treatment strategies. The anticipated outcome of this review is to provide valuable insights and pave the way for the advancement of effective and targeted therapies utilizing metal NPs specifically for cancer patients.

CD318 is a target of chimeric antigen receptor T cells for the treatment of colorectal cancer

Colorectal cancer (CRC) currently has a poor prognosis with a 6.9-year median survival time; to relieve this malignant cancer, we proposed to establish CRC xenografts that can be used to evaluate the cytotoxicity of adoptive chimeric antigen receptor (CAR)-T cells and accelerate the clinical translation of CAR-T cells for use against CRC. We first verified that CD318 had a higher expression level in primary human CRC tissues than in normal tissues based on hundreds of clinical samples. Then, we redirected CAR-T cells containing anti-CD318 single-chain variable fragment (anti-CD318 scFv), CD3ζ, CD28, and Toll-like receptor 2 (TLR2) domains. Next, we evaluated the function of these CAR-T cells in vitro in terms of surface phenotype changes, cytotoxicity and cytokine secretion when they encountered CD318+ CRC cells. Finally, we established two different xenograft mouse models to assess in vivo antitumor activity. The results showed that CAR318 T cells were significantly activated and exhibited strong cytotoxicity and cytokine-secreting abilities against CRC cells in vitro. Furthermore, CAR318 T cells induced CRC regression in different xenograft mouse models and suppressed tumors compared with CAR19 T cells. In summary, our work demonstrates that CAR318 T cells possess strong antitumor capabilities and represent a promising therapeutic approach for CRC.

Chimeric Peptide Engineered Bioregulator for Metastatic Tumor Immunotherapy through Macrophage Polarization and Phagocytosis Restoration

Tumor-associated macrophages (TAMs) are the most abundant immune cells in solid tumor tissues, which restrict antitumor immunity by releasing tumor-supporting cytokines and attenuating phagocytosis behaviors. In this work, a chimeric peptide engineered bioregulator (ChiP-RS) is constructed for tumor immunotherapy through macrophage polarization and phagocytosis restoration. ChiP-RS is fabricated by utilizing macrophage-targeting chimeric peptide (ChiP) to load Toll-like receptor agonists (R848) and Src homology 2 (SH2) domain-containing protein tyrosine phosphatase 2 (SHP-2) inhibitor (SHP099). Among which, ChiP-RS prefers to be internalized by TAMs, repolarizing M2 macrophages into M1 macrophages to reverse the immunosuppressive microenvironment. In addition, SHP-2 can be downregulated to promote phagocytotic elimination behaviors of M1 macrophages, which will also activate T cell-based antitumor immunity for metastatic tumor therapy. In vitro and in vivo findings demonstrate a superior suppression effect of ChiP-RS against metastatic tumors without systemic side effects. Such a simple but effective nanoplatform provides sophisticated synergism for immunotherapy, which may facilitate the development of translational nanomedicine for metastatic tumor treatment.

Clinical benefit and safety associated with mRNA vaccines for advanced solid tumors: A meta-analysis

Tumor mRNA vaccines have been developed for over 20 years. Whether mRNA vaccines could promote a clinical benefit to advanced cancer patients is highly unknown. PubMed and Embase were retrieved from January 1, 2000 to January 4, 2023. Random effects models were employed. Clinical benefit (objective response rate [ORR], disease control rate [DCR], 1-year/2-year progression-free survival [PFS], and overall survival [OS]) and safety (vaccine-related grade 3-5 adverse events [AEs]) were evaluated. Overall, 984 patients (32 trials) were enrolled. The most typical cancer types were melanoma (13 trials), non-small cell lung cancer (5 trials), renal cell carcinoma (4 trials), and prostate adenocarcinoma (4 trials). The pooled ORR and DCR estimates were 10.0% (95%CI, 4.6-17.0%) and 34.6% (95%CI, 24.1-45.9%). The estimates for 1-year and 2-year PFS were 38.4% (95%CI, 24.8-53.0%) and 20.0% (95%CI, 10.4-31.7%), respectively. The estimates for 1-year and 2-year OS were 75.3% (95%CI, 62.4-86.3%) and 45.5% (95%CI, 34.0-57.2%), respectively. The estimate for vaccine-related grade 3-5 AEs was 1.0% (95%CI, 0.2-2.4%). Conclusively, mRNA vaccines seem to demonstrate modest clinical response rates, with acceptable survival rates and rare grade 3-5 AEs.

Rational design of a Nivolumab-based ANTI-PD-1 single chain variable fragment that blocks the interaction between PD-1 expressed on T-CELLS and PD-L1 ON CHO cells

Antibodies that block the interaction between PD-1 expressing T-cells and cancer cells expressing PD-L1 play a central role in contemporary immunotherapy regimes [1-3]. We previously reported the isolation of a single chain variable fragment (scFv) of the monoclonal anti-PD-1 antibody Nivolumab, that binds to purified PD-1 and blocked its interaction with PD-L1 [4]. This anti-PD-1 scFv did not, however, function in a cell-based assay designed to detect the disruption of the PD-1/PD-L1 interaction, a result likely due to its poor solubility in tissue culture media. Herein we report that following a series of structure-based rational design analyses, including Aggreescan3D, we have isolated a variant of the anti-PD-1 scFv having significantly improved solubility in tissue culture medium. Moreover, this soluble anti-PD-1 scFv variant disrupted the interaction between PD-1 expressed on Jurkat Cells and PD-L1 expressed on CHO cells. These findings are discussed in terms of the related observation that the residues mutated to form the anti-PD-1 variant are conserved in many other scFvs; thus, the properties of a range of scFvs will likely be enhanced by similar mutations of the conserved residues.

CAR-T Cells with Phytohemagglutinin (PHA) Provide Anti-Cancer Capacity with Better Proliferation, Rejuvenated Effector Memory, and Reduced Exhausted T Cell Frequencies

The development of genetic modification techniques has led to a new era in cancer treatments that have been limited to conventional treatments such as chemotherapy. intensive efforts are being performed to develop cancer-targeted therapies to avoid the elimination of non-cancerous cells. One of the most promising approaches is genetically modified CAR-T cell therapy. The high central memory T cell (Tcm) and stem cell-like memory T cell (Tscm) ratios in the CAR-T cell population increase the effectiveness of immunotherapy. Therefore, it is important to increase the populations of CAR-expressing Tcm and Tscm cells to ensure that CAR-T cells remain long-term and have cytotoxic (anti-tumor) efficacy. In this study, we aimed to improve CAR-T cell therapy's time-dependent efficacy and stability, increasing the survival time and reducing the probability of cancer cell growth. To increase the sub-population of Tcm and Tscm in CAR-T cells, we investigated the production of a long-term stable and efficient cytotoxic CAR-T cell by modifications in the cell activation-dependent production using Phytohemagglutinin (PHA). PHA, a lectin that binds to the membranes of T cells and increases metabolic activity and cell division, is studied to increase the Tcm and Tscm population. Although it is known that PHA significantly increases Tcm cells, B-lymphocyte antigen CD19-specific CAR-T cell expansion, its anti-cancer and memory capacity has not yet been tested compared with aCD3/aCD28-amplified CAR-T cells. Two different types of CARs (aCD19 scFv CD8-(CD28 or 4-1BB)-CD3z-EGFRt)-expressing T cells were generated and their immunogenic phenotype, exhausted phenotype, Tcm-Tscm populations, and cytotoxic activities were determined in this study. The proportion of T cell memory phenotype in the CAR-T cell populations generated by PHA was observed to be higher than that of aCD3/aCD28-amplified CAR-T cells with similar and higher proliferation capacity. Here, we show that PHA provides long-term and efficient CAR-T cell production, suggesting a potential alternative to aCD3/aCD28-amplified CAR-T cells.

Allogeneic gene-edited HIV-specific CAR-T cells secreting PD-1 blocking scFv enhance specific cytotoxic activity against HIV Env+ cells invivo

HIV-specific chimeric antigen receptor (CAR) T-cells have been developed to target HIV-1 infected CD4⁺ T-cells that express HIV Env proteins. However, T cell exhaustion and the patient-specific autologous paradigm of CAR-T cell hurdled clinical applications. Here, we created HIV-specific CAR-T cells using human peripheral blood mononuclear cells and a 3BNC117-E27 (3BE) CAR construct that enabled the expression of programmed cell death protein (PD-1) -blocking scFv E27 and the single-chain variable fragment of the HIV-1-specific broadly neutralizing antibody 3BNC117 to target native HIV Env. Compared with T cells expressing 3BNC117-CAR alone, 3BE CAR-T cells showed greater cytotoxic activity against HIV Env⁺ cells with stronger proliferation capability, higher killing efficiency, and enhanced cytokine secretion in the presence of HIV Env-expressing cells. Furthermore, we manufactured TCR-deficient 3BE CAR-T cells through gene editing and demonstrated that these CAR-T cells could effectively kill HIV Env ​⁺ ​cells in vivo without the occurrence of severe graft-versus-host disease (GvHD) in NSG mice. These data suggest that we have provided a feasible approach to the generation of "off-the-shelf" anti-HIV CAR-T cells in combination with PD-1 checkpoint blockade immunotherapy, which can be a powerful therapeutic candidate for the functional cure of HIV.

GM-CSF-mediated inducement of bone marrow MDSCs by TSA and effect on survival of graft in mice

Objective

This study analyzed the effect of HDAC inhibitor, trichostatin A (TSA), in inducing granulocyte–macrophage colony-stimulating factor (GM-CSF)-mediated bone marrow (BM) cell differentiation to myeloid-derived suppressor cells (MDSCs) in vitro and in vivo.

Methods

BM cell differentiation to CD11b + GR-1 + MDSCs was achieved by in vitro culture with TSA and GM-CSF, and the collected cells were analyzed by mixed lymphocyte culture to identify suppressive actions against effector T cells. RT-PCR and ELISA were conducted to analyze the CCL5 mRNA and protein levels in TSA + GM-CSF + BM, GR-1 + MDSCs and GR-1 + MDSC + CCL5 groups. The survival of cardiac grafts was compared between groups.

Results

TSA was beneficial for the GM-CSF-mediated BM differentiation to CD11b + GR-1 + MDSCs. Adoptive transfer of GR-1 + MDSCs was powerful in suppressing CD4 + CD25-T cell proliferation and the effect was mediated by iNOS and HO-1; it also increased CCL5 gradient concentration between grafts and plasma to recruit Treg to grafts and prolong the survival of the grafts. Survival analysis revealed that the survival of grafts after adoptive transfer of GR-1 + MDSCs could be prolonged.

Conclusion

This study helps in further research on the application value of MDSCs in the field of transplant, and may provide a new thought for the cell therapy in inducing immune tolerance in organ transplant.

Development of Cancer Immunotherapies

Cancer immunotherapy, or the utilization of components of the immune system to target and eliminate cancer, has become a highly active area of research in the past several decades and a common treatment strategy for several cancer types. The concept of harnessing the immune system for this purpose originated over 100 years ago when a physician by the name of William Coley successfully treated several of his cancer patients with a combination of live and attenuated bacteria, later known as "Coley's Toxins", after observing a subset of prior patients enter remission following their diagnosis with the common bacterial infection, erysipelas. However, it was not until late in the twentieth century that cancer immunotherapies were developed for widespread use, thereby transforming the treatment landscape of numerous cancer types. Pivotal studies elucidating molecular and cellular functions of immune cells, such as the discovery of IL-2 and production of monoclonal antibodies, fostered the development of novel techniques for studying the immune system and ultimately the development and approval of several cancer immunotherapies by the United States Food and Drug Association in the 1980s and 1990s, including the tuberculosis vaccine-Bacillus Calmette-Guérin, IL-2, and the CD20-targeting monoclonal antibody. Approval of the first therapeutic cancer vaccine, Sipuleucel-T, for the treatment of metastatic castration-resistant prostate cancer and the groundbreaking success and approval of immune checkpoint inhibitors and chimeric antigen receptor T cell therapy in the last decade, have driven an explosion of interest in and pursuit of novel cancer immunotherapy strategies. A broad range of modalities ranging from antibodies to adoptive T cell therapies is under investigation for the generalized treatment of a broad spectrum of cancers as well as personalized medicine. This chapter will focus on the recent advances, current strategies, and future outlook of immunotherapy development for the treatment of cancer.

CD73 in small extracellular vesicles derived from HNSCC defines tumour-associated immunosuppression mediated by macrophages in the microenvironment

Research on tumour cell‐derived small extracellular vesicles (sEVs) that regulate tumour microenvironment (TME) has provided strategies for targeted therapy of head and neck squamous cell carcinoma (HNSCC). Herein, we demonstrated that sEVs derived from HNSCC cancer cells carried CD73 (sEVs^CD73), which promoted malignant progression and mediated immune evasion. The sEVs^CD73 phagocytosed by tumour‐associated macrophages (TAMs) in the TME induced immunosuppression. Higher CD73^high TAMs infiltration levels in the HNSCC microenvironment were correlated with poorer prognosis, while sEVs^CD73 activated the NF‐κB pathway in TAMs, thereby inhibiting immune function by increasing cytokines secretion such as IL‐6, IL‐10, TNF‐α, and TGF‐β1. The absence of sEVs^CD73 enhanced the sensitivity of anti‐PD‐1 therapy through reversed immunosuppression. Moreover, circulating sEVs^CD73 increased the risk of lymph node metastasis and worse prognosis. Taken together, our study suggests that sEVs^CD73 derived from tumour cells contributes to immunosuppression and is a potential predictor of anti‐PD‐1 responses for immune checkpoint therapy in HNSCC.

mRNA-Based Cancer Vaccines: A Therapeutic Strategy for the Treatment of Melanoma Patients

Malignant melanoma is one of the most aggressive forms of cancer and the leading cause of death from skin tumors. Given the increased incidence of melanoma diagnoses in recent years, it is essential to develop effective treatments to control this disease. In this regard, the use of cancer vaccines to enhance cell-mediated immunity is considered to be one of the most modern immunotherapy options for cancer treatment. The most recent cancer vaccine options are mRNA vaccines, with a focus on their usage as modern treatments. Advantages of mRNA cancer vaccines include their rapid production and low manufacturing costs. mRNA-based vaccines are also able to induce both humoral and cellular immune responses. In addition to the many advantages of mRNA vaccines for the treatment of cancer, their use is associated with a number of challenges. For this reason, before mRNA vaccines can be used for the treatment of cancer, comprehensive information about them is required and a large number of trials need to be conducted. Here, we reviewed the general features of mRNA vaccines, including their basis, stabilization, and delivery methods. We also covered clinical trials involving the use of mRNA vaccines in melanoma cancer and the challenges involved with this type of treatment. This review also emphasized the combination of treatment with mRNA vaccines with the use of immune-checkpoint blockers to enhance cell-mediated immunity.

Long-Term Follow-Up of Gemogenovatucel-T (Vigil) Survival and Molecular Signals of Immune Response in Recurrent Ovarian Cancer

Aim: To determine the relationship between gene expression profile (GEP) and overall survival (OS) by NanoString following treatment with Vigil. Patients and Methods: Recurrent ovarian cancer patients (n = 21) enrolled in prior clinical trials. Results: GEP stratified by TIS^HIGH vs. TIS^LOW demonstrated OS benefit (NR vs. 5.8 months HR 0.23; p = 0.0379), and in particular, MHC-II elevated baseline expression was correlated with OS advantage (p = 0.038). Moreover, 1-year OS was 75% in TIS^HIGH patients vs. 25% in TIS^LOW (p = 0.03795). OS was also correlated with positive γ-IFN ELISPOT response, 36.8 vs. 23.0 months (HR 0.19, p = 0.0098). Conclusion: Vigil demonstrates OS benefit in correlation with TIS^HIGH score, elevated MHC-II expression and positive γ-IFN ELISPOT in recurrent ovarian cancer patients.

Mechanisms that allow vaccination against an oncolytic vesicular stomatitis virus-encoded transgene to enhance safety without abrogating oncolysis

Vaccination can prevent viral infections via virus-specific T cells, among other mechanisms. A goal of oncolytic virotherapy is replication of oncolytic viruses (OVs) in tumors, so pre-existing T cell immunity against an OV-encoded transgene would seem counterproductive. We developed a treatment for melanomas by pre-vaccinating against an oncolytic vesicular stomatitis virus (VSV)-encoded tumor antigen. Surprisingly, when the VSV-vectored booster vaccine was administered at the peak of the primary effector T cell response, oncolysis was not abrogated. We sought to determine how oncolysis was retained during a robust T cell response against the VSV-encoded transgene product. A murine melanoma model was used to identify two mechanisms that enable this phenomenon. First, tumor-infiltrating T cells had reduced cytopathic potential due to immunosuppression. Second, virus-induced lymphopenia acutely removed virus-specific T cells from tumors. These mechanisms provide a window of opportunity for replication of oncolytic VSV and rationale for a paradigm change in oncolytic virotherapy, whereby immune responses could be intentionally induced against a VSV-encoded melanoma-associated antigen to improve safety without abrogating oncolysis.

IL-33/ST2 as a potential target for tumor immunotherapy

IL-33, a member of the IL-1 family, was initially reported to be expressed constitutively in the nucleus of tissue-lining and structural cells. However, upon tissue damage or injury, IL-33 can be released quickly to bind with its cognate receptor ST2 in response to wound healing and inflammation and act as a DAMP. As a key regulator of Th2 responses, IL-33/ST2 signal is primarily associated with immunity and immune-related disorders. In recent years, IL-33/ST2 signaling pathway has been reported to promote the development of cancer and remodel the tumor microenvironment by expanding immune suppressive cells such as myeloid-derived suppressor cells or regulatory T cells. However, its role remains controversial in some tumor settings. IL-33 could also promote effective infiltration of immune cells such as CD8⁺ T and NK cells, which act as antitumor. These dual effects may limit the clinical application to target this cytokine axis. Therefore, more comprehensive exploration and deeper understanding of IL-33 are required. In this review, we summarized the IL-33/ST2 axis versatile roles in the tumor microenvironment with a focus on the IL-33-target immune cells and downstream signaling pathways. We also discuss how the IL-33/ST2 axis could be used as a potential therapeutic target for cancer immunotherapy.

Clinical and immunological effects of mRNA vaccines in malignant diseases

In vitro-transcribed messenger RNA-based therapeutics represent a relatively novel and highly efficient class of drugs. Several recently published studies emphasize the potential efficacy of mRNA vaccines in treating different types of malignant and infectious diseases where conventional vaccine strategies and platforms fail to elicit protective immune responses. mRNA vaccines have lately raised high interest as potent vaccines against SARS-CoV2. Direct application of mRNA or its electroporation into dendritic cells was shown to induce polyclonal CD4+ and CD8+ mediated antigen-specific T cell responses as well as the production of protective antibodies with the ability to eliminate transformed or infected cells. More importantly, the vaccine composition may include two or more mRNAs coding for different proteins or long peptides. This enables the induction of polyclonal immune responses against a broad variety of epitopes within the encoded antigens that are presented on various MHC complexes, thus avoiding the restriction to a certain HLA molecule or possible immune escape due to antigen-loss. The development and design of mRNA therapies was recently boosted by several critical innovations including the development of technologies for the production and delivery of high quality and stable mRNA. Several technical obstacles such as stability, delivery and immunogenicity were addressed in the past and gradually solved in the recent years.This review will summarize the most recent technological developments and application of mRNA vaccines in clinical trials and discusses the results, challenges and future directions with a special focus on the induced innate and adaptive immune responses.

Harnessing immunity for therapy in human papillomavirus driven cancers

In persistent high-risk HPV infection, viral gene expression can trigger some important early changes to immune capabilities which act to protect the lesion from immune attack and subsequently promote its growth and ability for sustained immune escape. This includes immune checkpoint-inhibitor ligand expression (e.g. PD-L1) by tumour or associated immune cells that can block any anti-tumour T-cell effectors. While there are encouraging signs of efficacy for cancer immunotherapies including with immune checkpoint inhibitors, therapeutic vaccines and adoptive cell therapies, overall response and survival rates remain relatively low. HPV oncogene vaccination has shown some useful efficacy in treatment of patients with high-grade lesions but was unable to control later stage cancers. To maximally exploit anti-tumour immune responses, the suppressive factors associated with HPV carcinogenesis must be countered. Importantly, a combination of chemotherapy, reducing immunosuppressive myeloid cells, with therapeutic HPV vaccination significantly improves impact on cancer treatment. Many clinical trials are investigating checkpoint inhibitor treatments in HPV associated cancers but response rates are limited; combination with vaccination is being tested. Further investigation of how chemo- and/or radio-therapy can influence the recovery of effective anti-tumour immunity is warranted. Understanding how to optimally deploy and sequence conventional and immunotherapies is the challenge.

Inorganic Nanomaterial-Mediated Gene Therapy in Combination with Other Antitumor Treatment Modalities

Cancer is a genetic disease originating from the accumulation of gene mutations in a cellular subpopulation. Although many therapeutic approaches have been developed to treat cancer, recent studies have revealed an irrefutable challenge that tumors evolve defenses against some therapies. Gene therapy may prove to be the ultimate panacea for cancer by correcting the fundamental genetic errors in tumors. The engineering of nanoscale inorganic carriers of cancer therapeutics has shown promising results in the efficacious and safe delivery of nucleic acids to treat oncological diseases in small-animal models. When these nanocarriers are used for co-delivery of gene therapeutics along with auxiliary treatments, the synergistic combination of therapies often leads to an amplified health benefit. In this review, an overview of the inorganic nanomaterials developed for combinatorial therapies of gene and other treatment modalities is presented. First, the main principles of using nucleic acids as therapeutics, inorganic nanocarriers for medical applications and delivery of gene/drug payloads are introduced. Next, the utility of recently developed inorganic nanomaterials in different combinations of gene therapy with each of chemo, immune, hyperthermal, and radio therapy is examined. Finally, current challenges in the clinical translation of inorganic nanomaterial-mediated therapies are presented and outlooks for the field are provided.

Characterization of a single chain variable fragment of nivolumab that targets PD-1 and blocks PD-L1 binding

Activated T-cells express Programmed cell Death protein 1 (PD-1), a key immune checkpoint receptor. PD-1 functions primarily in peripheral tissues, where T cells may encounter tumor-derived immunosuppressive ligands. Monoclonal antibodies that disrupt the interaction between T-cell derived PD-1 and immunosuppressive ligands, such as PD-L1, have revolutionized approaches to cancer therapy. For instance, Nivolumab is a monoclonal Ab that targets human PD-1 and has played an important role in immune checkpoint therapy. Herein we report the purification and initial characterization of a ~27 kDa single chain variable fragment (scFv) of Nivolumab that targets human PD-1 and blocks binding by PD-L1. The possibility that the anti-PD-1 scFv can serve as both an anti-tumor agent and as an anti-viral agent is discussed. IMPORTANCE: The clinical significance of anti-PD-1 antibodies for treatment of a range of solid tumors is well documented (reviewed in [1-4]). In this report, we describe the results of studies that establish that an anti-PD-1 scFv purified from E. coli binds tightly to human PD-1. Furthermore, we demonstrate that upon binding, the anti-PD-1 scFv disrupts the interaction between PD-1 and PD-L1. Thus, the properties of this scFv, including its small size, stability and affinity for human PD-1, suggest that it has the potential to be a useful reagent in subsequent immunotherapeutic, diagnostic and anti-viral applications.

Preclinical Assessment of Efficacy and Safety Analysis of CAR-T Cells (ISIKOK-19) Targeting CD19-Expressing B-Cells for the First Turkish Academic Clinical Trial with Relapsed/Refractory ALL and NHL Patients

Objective

Relapsed and refractory CD19-positive B-cell acute lymphoblastic leukemia (ALL) and non-Hodgkin lymphoma (NHL) are the focus of studies on hematological cancers. Treatment of these malignancies has undergone recent transformation with the development of new gene therapy and molecular biology techniques, which are safer and well-tolerated therapeutic approaches. The CD19 antigen is the most studied therapeutic target in these hematological cancers. This study reports the results of clinical-grade production, quality control, and in vivo efficacy processes of ISIKOK-19 cells as the first academic clinical trial of CAR-T cells targeting CD19-expressing B cells in relapsed/refractory ALL and NHL patients in Turkey.

Materials and Methods

We used a lentiviral vector encoding the CD19 antigen-specific antibody head (FMC63) conjugated with the CD8-CD28-CD3ζ sequence as a chimeric antigen receptor (CAR) along with a truncated form of EGFR (EGFRt) on human T-lymphocytes (CAR-T). We preclinically assessed the efficacy and safety of the manufactured CAR-T cells, namely ISIKOK-19, from both healthy donors’ and ALL/NHL patients’ peripheral blood mononuclear cells.

Results

We showed significant enhancement of CAR lentivirus transduction efficacy in T-cells using BX-795, an inhibitor of the signaling molecule TBK1/IKKƐ, in order to cut the cost of CAR-T cell production. In addition, ISIKOK-19 cells demonstrated a significantly high level of cytotoxicity specifically against a CD19+ B-lymphocyte cancer model, RAJI cells, in NOD/SCID mice.

Conclusion

This is the first report of preclinical assessment of efficacy and safety analysis of CAR-T cells (ISIKOK-19) targeting CD19-expressing B cells in relapsed/refractory ALL and NHL patients in Turkey.

Hyperthermia Targeting the Tumor Microenvironment Facilitates Immune Checkpoint Inhibitors

Immune checkpoint inhibitors (ICIs) have ushered in a new era of cancer therapy; however, ICIs are only effective in selective patients. The efficacy of ICIs is closely related to the tumor microenvironment. Fever for a long time was thought to directly regulate the immune response, and artificial “fever” from hyperthermia modulates the tumor immune microenvironment by providing danger signals with heat shock proteins (HSPs) as well as subsequent activation of immune systems. Encouraging results have been achieved in preclinical studies focused on potential synergetic effects by combining hyperthermia with ICIs. In this review, we summarized a cluster of immune-related factors that not only make hyperthermia a treatment capable of defending against cancer but also make hyperthermia a reliable treatment that creates a type I-like tumor microenvironment (overexpression of PD-L1 and enrichment of tumor infiltrating lymphocytes) in complementary for the enhancement of the ICIs. Then we reviewed recent preclinical data of the combination regimens involving hyperthermia and ICIs that demonstrated the combined efficacy and illustrated possible approaches to further boost the effectiveness of this combination.

Principles of Immunotherapy in Melanoma

Advanced/metastatic melanoma is an aggressive cancer with a low survival rate. Traditional cytotoxic chemotherapies do not appreciably extend life and systemic cytokine/chemokine administration produces toxic side effects. By harnessing the surveillance and cytotoxic features of the immune system, immunotherapies can provide a durable response and are proved to improve disease outcomes in patients with advanced/metastatic melanoma and other cancers. Close monitoring is necessary, however, to identify and treat immune system-related adverse events before they become life-threatening. Because metastatic lesions can respond differently to immunotherapies, modified response criteria have been developed to assist physicians in tracking patient response to treatment.

Multifaceted Role of the Placental Growth Factor (PlGF) in the Antitumor Immune Response and Cancer Progression

The sharing of molecules function that affects both tumor growth and neoangiogenesis with cells of the immune system creates a mutual interplay that impairs the host’s immune response against tumor progression. Increasing evidence shows that tumors are able to create an immunosuppressive microenvironment by recruiting specific immune cells. Moreover, molecules produced by tumor and inflammatory cells in the tumor microenvironment create an immunosuppressive milieu able to inhibit the development of an efficient immune response against cancer cells and thus fostering tumor growth and progression. In addition, the immunoediting could select cancer cells that are less immunogenic or more resistant to lysis. In this review, we summarize recent findings regarding the immunomodulatory effects and cancer progression of the angiogenic growth factor namely placental growth factor (PlGF) and address the biological complex effects of this cytokine. Different pathways of the innate and adaptive immune response in which, directly or indirectly, PlGF is involved in promoting tumor immune escape and metastasis will be described. PlGF is important for building up vascular structures and functions. Although PlGF effects on vascular and tumor growth have been widely summarized, its functions in modulating the immune intra-tumoral microenvironment have been less highlighted. In agreement with PlGF functions, different antitumor strategies can be envisioned.

Function of Human Tumor-Infiltrating Lymphocytes in Early-Stage Non-Small Cell Lung Cancer

Cancer progression is marked by dysfunctional tumor-infiltrating lymphocytes (TIL) with high inhibitory receptor (IR) expression. Because IR blockade has led to clinical responses in some patients with non-small cell lung cancer (NSCLC), we investigated how IRs influenced CD8+ TIL function from freshly digested early-stage NSCLC tissues using a killing assay and intracellular cytokine staining after in vitro T-cell restimulation. Early-stage lung cancer TIL function was heterogeneous with only about one third of patients showing decrements in cytokine production and lytic function. TIL hypofunction did not correlate with clinical factors, coexisting immune cells (macrophages, neutrophils, or CD4+ T regulatory cells), nor with PD-1, TIGIT, TIM-3, CD39, or CTLA-4 expression. Instead, we found that the presence of the integrin αeβ7 (CD103), characteristic of tissue-resident memory cells (TRM), was positively associated with cytokine production, whereas expression of the transcription factor Eomesodermin (Eomes) was negatively associated with TIL function. These data suggest that the functionality of CD8+ TILs from early-stage NSCLCs may be influenced by competition between an antitumor CD103+ TRM program and an exhaustion program marked by Eomes expression. Understanding the mechanisms of T-cell function in the progression of lung cancer may have clinical implications for immunotherapy.

Technologies for the Directed Evolution of Cell Therapies

The next generation of therapies is moving beyond the use of small molecules and proteins to using whole cells. Compared with the interactions of small-molecule drugs with biomolecules, which can largely be understood through chemistry, cell therapies act in a chemical and physical world and can actively adapt to that world, amplifying complexity but also the potential for truly breakthrough impact. Although there has been success in introducing targeting proteins into cells to achieve a therapeutic effect, for example, chimeric antigen receptor (CAR) T cells, our ability to engineer cells is generally limited to introducing proteins, but not modulating large-scale traits or structures of cellular "machines," which play critical roles in disease. Example traits include the ability to secrete compounds, deform through tissue, adhere to surrounding cells, apply force to phagocytose targets, or move through extracellular matrix. There is an opportunity to increase the efficacy of cell therapies through the use of quantitative automation tools, to analyze, sort, and select rare cells with beneficial traits. Combined with methods of genetic or epigenetic mutagenesis to create diversity, such approaches can enable the directed cellular evolution of new therapeutically optimal populations of cells and uncover genetic underpinnings of these optimal traits.

Targeting the tumor microenvironment to overcome immune checkpoint blockade therapy resistance

The ability of immune checkpoint inhibitors (ICIs) to reactivate the killing function of the immune system to tumor cells has led to long lasting immune response presenting highly promising clinical advances. Recently, immune checkpoint inhibitors related resistance due to the specialized tumor microenvironment has also drawn a widely attention. To overcome resistance to immune checkpoint blockade therapy, understanding the relationship of this type of therapy and tumor microenvironment is necessary and critical. This review will focus on how the tumor environment influences the effectiveness of the immunotherapeutic check inhibitors. Finally, we provide a briefly succinct glimpse into the most exciting pre-clinical discoveries and ongoing clinical trials to overcome the resistance of ICIs.

Therapeutic Cancer Vaccines-T Cell Responses and Epigenetic Modulation

There is great interest in developing efficient therapeutic cancer vaccines, as this type of therapy allows targeted killing of tumor cells as well as long-lasting immune protection. High levels of tumor-infiltrating CD8⁺ T cells are associated with better prognosis in many cancers, and it is expected that new generation vaccines will induce effective production of these cells. Epigenetic mechanisms can promote changes in host immune responses, as well as mediate immune evasion by cancer cells. Here, we focus on epigenetic modifications involved in both vaccine-adjuvant-generated T cell immunity and cancer immune escape mechanisms. We propose that vaccine-adjuvant systems may be utilized to induce beneficial epigenetic modifications and discuss how epigenetic interventions could improve vaccine-based therapies. Additionally, we speculate on how, given the unique nature of individual epigenetic landscapes, epigenetic mapping of cancer progression and specific subsequent immune responses, could be harnessed to tailor therapeutic vaccines to each patient.

CD8 T Cell Exhaustion During Chronic Viral Infection and Cancer

Exhausted CD8 T (Tex) cells are a distinct cell lineage that arise during chronic infections and cancers in animal models and humans. Tex cells are characterized by progressive loss of effector functions, high and sustained inhibitory receptor expression, metabolic dysregulation, poor memory recall and homeostatic self-renewal, and distinct transcriptional and epigenetic programs. The ability to reinvigorate Tex cells through inhibitory receptor blockade, such as αPD-1, highlights the therapeutic potential of targeting this population. Emerging insights into the mechanisms of exhaustion are informing immunotherapies for cancer and chronic infections. However, like other immune cells, Tex cells are heterogeneous and include progenitor and terminal subsets with unique characteristics and responses to checkpoint blockade. Here, we review our current understanding of Tex cell biology, including the developmental paths, transcriptional and epigenetic features, and cell intrinsic and extrinsic factors contributing to exhaustion and how this knowledge may inform therapeutic targeting of Tex cells in chronic infections, autoimmunity, and cancer.

Targeted delivery of a PD-1-blocking scFv by CAR-T cells enhances anti-tumor efficacy in vivo

The efficacy of chimeric antigen receptor (CAR) T cell therapy against poorly responding tumors can be enhanced by administering the cells in combination with immune checkpoint blockade inhibitors. Alternatively, the CAR construct has been engineered to coexpress factors that boost CAR-T cell function in the tumor microenvironment. We modified CAR-T cells to secrete PD-1-blocking single-chain variable fragments (scFv). These scFv-secreting CAR-T cells acted in both a paracrine and autocrine manner to improve the anti-tumor activity of CAR-T cells and bystander tumor-specific T cells in clinically relevant syngeneic and xenogeneic mouse models of PD-L1+ hematologic and solid tumors. The efficacy was similar to or better than that achieved by combination therapy with CAR-T cells and a checkpoint inhibitor. This approach may improve safety, as the secreted scFvs remained localized to the tumor, protecting CAR-T cells from PD-1 inhibition, which could potentially avoid toxicities associated with systemic checkpoint inhibition.

Ultrasound-mediated microbubble destruction: a new method in cancer immunotherapy

Immunotherapy provides a new treatment option for cancer. However, it may be therapeutically insufficient if only using the self-immune system alone to attack the tumor without any aiding methods. To overcome this drawback and improve the efficiency of therapy, new treatment methods are emerging. In recent years, ultrasound-mediated microbubble destruction (UMMD) has shown great potential in cancer immunotherapy. Using the combination of ultrasound and targeted microbubbles, molecules such as antigens or genes encoding antigens can be efficiently and specifically delivered into the tumor tissue. This review focuses on the recent progress in the application of UMMD in cancer immunotherapy.

Regulation of T cell immunity by cellular metabolism

T cells are an important adaptive immune response arm that mediates cell-mediated immunity. T cell metabolism plays a central role in T cell activation, proliferation, differentiation, and effector function. Specific metabolic programs are tightly controlled to mediate T cell immune responses, and alterations in T cell metabolism may result in many immunological disorders. In this review, we will summarize the main T cell metabolic pathways and the important factors participating in T cell metabolic programming during T cell homeostasis, differentiation, and function.

Immunochemotherapy mediated by thermosponge nanoparticles for synergistic anti-tumor effects

The efficacy of immunotherapy was demonstrated to be compromised by reduced immunogenicity of tumor cells and enhanced suppressive properties of the tumor microenvironment in cancer treatment. There is growing evidence that low-dose chemotherapy can modulate the immune system to improve the anti-tumor effects of immunotherapy through multiple mechanisms, including the enhancement of tumor immunogenicity and reversal of the immunosuppressive tumor microenvironment. Here, we fabricated thermosponge nanoparticles (TSNs) for the co-delivery of chemotherapeutic drug paclitaxel (PTX) and immunostimulant interleukin-2 (IL-2) to explore the synergistic anti-tumor effects of chemotherapy and immunotherapy. The distinct temperature-responsive swelling/deswelling character facilitated the effective post-entrapment of cytokine IL-2 in nanoparticles by a facile non-solvent mild incubation method with unaffected bioactivity and favorable pharmacokinetics. PTX and IL-2 co-loaded TSNs exhibited significant inhibition on tumor growth and metastasis, and prolonged overall survival for tumor-bearing mice compared with the corresponding monotherapies. The synergistic effect was evidenced from the remodeled tumor microenvironment in which low-dose chemotherapeutics disrupted the immunosuppressive tumor microenvironment and enhanced tumor immunogenicity, and immunostimulant cytokine promoted the anti-tumor immune response of immune effector cells. The immunochemotherapy mediated by this thermosponge nanoplatform may provide a promising treatment strategy against cancer.

Immune Modulatory microRNAs Involved in Tumor Attack and Tumor Immune Escape

Current therapies against cancer utilize the patient's immune system for tumor eradication. However, tumor cells can evade immune surveillance of CD8+ T and/or natural killer (NK) cells by various strategies. These include the aberrant expression of human leukocyte antigen (HLA) class I antigens, co-inhibitory or costimulatory molecules, and components of the interferon (IFN) signal transduction pathway. In addition, alterations of the tumor microenvironment could interfere with efficient antitumor immune responses by downregulating or inhibiting the frequency and/or functional activity of immune effector cells and professional antigen-presenting cells. Recently, microRNAs (miRNAs) have been identified as major players in the post-transcriptional regulation of gene expression, thereby controlling many physiological and also pathophysiological processes including neoplastic transformation. Indeed, the cellular miRNA expression pattern is frequently altered in many tumors of distinct origin, demonstrating the tumor suppressive or oncogenic potential of miRNAs. Furthermore, there is increasing evidence that miRNAs could also influence antitumor immune responses by affecting the expression of immune modulatory molecules in tumor and immune cells. Apart from their important role in tumor immune escape and altered tumor-host interaction, immune modulatory miRNAs often exert neoplastic properties, thus representing promising targets for future combined immunotherapy approaches. This review focuses on the characterization of miRNAs involved in the regulation of immune surveillance or immune escape of tumors and their potential use as diagnostic and prognostic biomarkers or as therapeutic targets.

The Inhibitory Signaling Receptor Protocadherin-18 Regulates Tumor-Infiltrating CD8+ T-cell Function

Cancers are infiltrated with antitumor CD8⁺ T cells that arise during tumor growth, but are defective in effector phase functions because of the suppressive microenvironment. The reactivation of TILs can result in tumor destruction, showing that lytic dysfunction in CD8⁺ tumor-infiltrating lymphocytes (TIL) permits tumor growth. Like all memory T cells, TILs express inhibitory signaling receptors (aka checkpoint inhibitor molecules) that downregulate TCR-mediated signal transduction upon TIL interaction with cells expressing cognate ligands, thereby restricting cell activation and preventing the effector phase. Previously, we identified a novel murine CD8⁺ TIL inhibitory signaling receptor, protocadherin-18, and showed that it interacts with p56^lck kinase to abrogate proximal TCR signaling. Here, we show that TILs from mice deleted in protocadherin-18 had enhanced antitumor activity and that coblockade of PD-1 and protocadherin-18 in wild-type mice significantly enhanced TIL effector phase function. These results define an important role for protocadherin-18 in antitumor T-cell activity. Cancer Immunol Res; 5(10); 920-8. ©2017 AACR.

Tumor-derived factors affecting immune cells

Tumor progression is accompanied by the production of a wide array of immunosuppressive factors by tumor and non-tumor cells forming the tumor microenvironment. These factors belonging to cytokines, growth factors, metabolites, glycan-binding proteins and glycoproteins are responsible for the establishment of immunosuppressive networks leading towards tumor promotion, invasion and metastasis. In pre-clinical tumor models, the inactivation of some of these suppressive networks reprograms the phenotypic and functional features of tumor-infiltrating immune cells, ultimately favoring effective anti-tumor immune responses. We will discuss factors and mechanisms identified in both mouse and human tumors, and the possibility to associate drugs inhibiting these mechanisms with new immunotherapy strategies already entered in the clinical practice.

Impact of Metabolism on T-Cell Differentiation and Function and Cross Talk with Tumor Microenvironment

The immune system and metabolism are highly integrated and multilevel interactions between metabolic system and T lymphocyte signaling and fate exist. Accumulating evidence indicates that the regulation of nutrient uptake and utilization in T cells is critically important for the control of their differentiation and manipulating metabolic pathways in these cells can shape their function and survival. This review will discuss some potential cell metabolism pathways involved in shaping T lymphocyte function and differentiation. It will also describe show subsets of T cells have specific metabolic requirements and signaling pathways that contribute to their respective function. Examples showing the apparent similarity between cancer cell metabolism and T cells during activation are illustrated and finally some mechanisms being used by tumor microenvironment to orchestrate T-cell metabolic dysregulation and the subsequent emergence of immune suppression are discussed. We believe that targeting T-cell metabolism may provide an additional opportunity to manipulate T-cell function in the development of novel therapeutics.

Immunotherapy: Beyond Anti-PD-1 and Anti-PD-L1 Therapies

Advanced-stage non-small cell lung cancer (NSCLC) and small cell lung cancer are cancers in which chemotherapy produces a survival benefit, although it is small. We now know that anti-PD-1/PD-L1 has substantial clinical activity in both of these diseases, with an overall response rate (ORR) of 15%-20%. These responses are frequently rapid and durable, increase median overall survival (OS) compared with chemotherapy, and produce long-term survivors. Despite these very significant results, many patients do not benefit from anti-PD-1/PD-L1. This is because of the potential for malignancies to co-opt myriad immunosuppressive mechanisms other than aberrant expression of PD-L1. Conceptually, these can be divided into three categories. First, for some patients there is likely a failure to generate sufficient functional tumor antigen-specific T cells. Second, for others, tumor antigen-specific T cells may be generated but fail to enter into the tumor parenchyma. Finally, there are a large number of immunosuppressive mechanisms that have the potential to be operational within the tumor microenvironment: surface membrane immune checkpoint proteins PD-1, CTLA-4, LAG3, TIM3, BTLA, and adenosine A2AR; soluble factors and metabolic alterations interleukin (IL)-10, transforming growth factor (TGF)-β, adenosine, IDO, and arginase; and inhibitory cells, cancer-associated fibroblasts (CAFs), regulatory T cells, myeloid-derived suppressor cells (MDSCs), and tumor-associated macrophages. In this article, we discuss three strategies to generate more tumor-reactive T cells for patients: anti-CTLA-4, therapeutic tumor vaccination, and adoptive cellular therapy, with T cells redirected to tumor antigens using T-cell receptor (TCR) or chimeric antigen receptor (CAR) gene modification. We also review some of the various strategies in development to thwart tumor microenvironment immunosuppressive mechanisms. Strategies to drive more T cells into tumors remain a significant challenge.

Analysis of Important Gene Ontology Terms and Biological Pathways Related to Pancreatic Cancer

Pancreatic cancer is a serious disease that results in more than thirty thousand deaths around the world per year. To design effective treatments, many investigators have devoted themselves to the study of biological processes and mechanisms underlying this disease. However, it is far from complete. In this study, we tried to extract important gene ontology (GO) terms and KEGG pathways for pancreatic cancer by adopting some existing computational methods. Genes that have been validated to be related to pancreatic cancer and have not been validated were represented by features derived from GO terms and KEGG pathways using the enrichment theory. A popular feature selection method, minimum redundancy maximum relevance, was employed to analyze these features and extract important GO terms and KEGG pathways. An extensive analysis of the obtained GO terms and KEGG pathways was provided to confirm the correlations between them and pancreatic cancer.

Mesenchymal Stromal Cells Can Regulate the Immune Response in the Tumor Microenvironment

The tumor microenvironment is a good target for therapy in solid tumors and hematological malignancies. Indeed, solid tumor cells' growth and expansion can influence neighboring cells' behavior, leading to a modulation of mesenchymal stromal cell (MSC) activities and remodeling of extracellular matrix components. This leads to an altered microenvironment, where reparative mechanisms, in the presence of sub-acute inflammation, are not able to reconstitute healthy tissue. Carcinoma cells can undergo epithelial mesenchymal transition (EMT), a key step to generate metastasis; these mesenchymal-like cells display the functional behavior of MSC. Furthermore, MSC can support the survival and growth of leukemic cells within bone marrow participating in the leukemic cell niche. Notably, MSC can inhibit the anti-tumor immune response through either carcinoma-associated fibroblasts or bone marrow stromal cells. Experimental data have indicated their relevance in regulating cytolytic effector lymphocytes of the innate and adaptive arms of the immune system. Herein, we will discuss some of the evidence in hematological malignancies and solid tumors. In particular, we will focus our attention on the means by which it is conceivable to inhibit MSC-mediated immune suppression and trigger anti-tumor innate immunity.

Molecular mechanisms of HLA class I-mediated immune evasion of human tumors and their role in resistance to immunotherapies

Although the human immune system can recognize and eradicate tumor cells, tumors have also been shown to develop different strategies to escape immune surveillance, which has been described for the first time in different mouse models. The evasion of immune recognition was often associated with a poor prognosis and reduced survival of patients. During the last years the molecular mechanisms, which protect tumor cells from this immune attack, have been identified and appear to be more complex than initially expected. However, next to the composition of cellular, soluble and physical components of the tumor microenvironment, the tumor cells changes to limit immune responses. Of particular importance are classical and non-classical human leukocyte antigen (HLA) class I antigens, which often showed a deregulated expression in cancers of distinct origin. Furthermore, HLA class I abnormalities were linked to defects in the interferon signaling, which have both been shown to be essential for mounting immune responses and are involved in resistances to T cell-based immunotherapies. Therefore this review summarizes the expression, regulation, function and clinical relevance of HLA class I antigens in association with the interferon signal transduction pathway and its role in adaptive resistances to immunotherapies.

Drug Development for Metastasis Prevention

Metastatic disease is responsible for 90% of death from solid tumors. However, only a minority of metastasis-specific targets has been exploited therapeutically, and effective prevention and suppression of metastatic disease is still an elusive goal. In this review, we will first summarize the current state of knowledge about the molecular features of the disease, with particular focus on steps and targets potentially amenable to therapeutic intervention. We will then discuss the reasons underlying the paucity of metastatic drugs in the current oncological arsenal and potential ways to overcome this therapeutic gap. We reason that the discovery of novel promising targets, an increased understanding of the molecular features of the disease, the effect of disruptive technologies, and a shift in the current preclinical and clinical settings have the potential to create more successful drug development endeavors.