Pharmacal Research

Evolution of chimeric antigen receptor (CAR) T cell therapy: current status and future perspectives Abstract Engineering T cells with a chimeric antigen receptor (CAR) that reprograms their antigen selectivity and signaling has recently emerged as one of the most promising therapeutic approaches for treating cancers. For example, two CD19-specific CAR T cell (CAR-T) therapies have shown remarkable responses in patients with relapsed/refractory B-cell cancers, and were approved by the US Food and Drug Administration in 2017. This initial clinical success has spurred an explosion of interests in this novel therapy from both academia and industry, and results from basic and clinical research have enabled the rapid evolution of the CAR-T field. In this review, we describe the basic structure of the CAR and discuss how each of its domains affect the efficacy and safety of CAR-T therapies. In addition, we discuss some of the novel concepts and other considerations that are essential for ensuring the future success of CAR-T therapy.

Natural killer cells as a promising therapeutic target for cancer immunotherapy Abstract Natural killer (NK) cells are innate lymphoid cells that provide early protection against cancer development via their selectivity to kill abnormal cells undergoing cellular transformation without the need for prior stimulation. Given the correlation between NK cell dysfunction and cancer prognosis, restoration of endogenous NK cells in the tumor microenvironment or adoptive transfer of NK cells with improved function holds great promise in cancer treatment. Furthermore, MHC-unrestricted tumor lysis by NK cells complements the MHC-restricted killing of tumor cells by cytotoxic T cells, thus positioning NK cells as an alternative or complementary therapeutic target for cancers that are refractory to T cell-based therapy. Although previous therapeutic strategies have focused on the manipulation of NK cell inhibitory receptors, recent advances in our understanding of NK cell activation have provided additional promising strategies to enhance NK cell reactivity against cancer. These approaches include targeting immunosuppressive mechanisms in the tumor microenvironment, such as immune checkpoint receptors, and further enhancing NK cell activation via modulation of intracellular checkpoint molecules or incorporation of tumor-directed chimeric antigen receptors. Thus, an in-depth understanding of NK cell activation will facilitate the optimal design of therapeutic strategies against refractory cancers, possibly in rational and synergistic combination with other therapies.

Phosphatidylserine receptor-targeting therapies for the treatment of cancer Abstract Asymmetric distribution of phospholipids across the plasma membrane is a unique characteristic of eukaryotic cells. Phosphatidylcholine and sphingomyelin are exposed in the outer leaflet, and phosphatidylserine (PS) is predominantly located in the inner leaflet. Redistribution of PS to the cell surface can be observed in several physiological conditions, such as apoptosis and platelet activation, or in pathological conditions, such as the release of microvesicles/exosomes from tumor tissues. PS binding to the phosphatidylserine receptor (PSR) on immune cells initiates immunosuppressive pathways that can lead to immune evasion by cancer cells. Conversely, PSR activation of cancer cells plays an important role in their survival, proliferation and metastasis. Herein, we briefly summarize both recent advances in our understanding of the pathological roles of PS and its receptor in cancer biology, as well as relevant pharmacological approaches.

Natural compound inducers of immunogenic cell death Abstract Accumulating evidence shows that the anti-cancer potential of the immune response that can be activated by modulation of the immunogenicity of dying cancer cells. This regulated cell death process is called immunogenic cell death (ICD) and constitutes a new innovating anti-cancer strategy with immune-modulatory potential thanks to the release of damage-associated molecular patterns (DAMPs). Some conventional clinically-used chemotherapeutic drugs, as well as preclinically-investigated compounds of natural origins such as anthracyclines, microtubule-destabilizing agents, cardiac glycosides or hypericin derivatives, possess such an immune-stimulatory function by triggering ICD. Here, we discuss the effects of ICD inducers on the release of DAMPs and the activation of corresponding signaling pathways triggering immune recognition. We will discuss potential strategies allowing to overcome resistance mechanisms associated with this treatment approach as well as co-treatment strategies to overcome the immunosuppressive microenvironment. We will highlight the potential role of metronomic immune modulation as well as targeted delivery of ICD-inducing compounds with nanoparticles or liposomal formulations to improving the immunogenicity of ICD inducers aiming at long-term clinical benefits.

Roles of NKT cells in cancer immunotherapy Abstract Cancer immunotherapy has emerged as an effective therapeutic strategy to treat cancer. Among diverse immune populations, invariant natural killer T (iNKT) cells have shown potent antitumor activity by linking innate and adaptive immune systems. Upon activation by lipid antigens on CD1d molecules, iNKT cells rapidly produce various cytokines and trigger antitumor immunity directly or indirectly by activating other antitumor immune cells. Administration of a representative iNKT cell ligand alpha-galactosylceramide (α-GalCer) or α-GalCer-pulsed APCs effectively stimulates iNKT cells and thereby induces antitumor effects. In this review, we will introduce the biology and importance of NKT cells in antitumor immunity. Previous studies have demonstrated that iNKT cells not only activate various immune cells but also reinvigorate exhausted immune cells in the tumor microenvironment. Furthermore, we will summarize the major clinical trials utilizing iNKT-based immunotherapies.

T helper 17 (Th17) cells and interleukin-17 (IL-17) in cancer Abstract Th17 cells are a specialized subset of CD4+ T cells that are essential in driving inflammation during autoimmune disease and infection through a signature cytokine IL-17. Th17 cells have been found in various human cancers. The function of these cells in cancers is highly context-dependent; both tumor-promoting and tumor-suppressing activity have been reported. IL-17 and IL-22, Th17-derived cytokines, influence the tumor microenvironment by directly promoting transformed cell properties and neighboring stromal cell activity. These cytokines are also involved in regulation of the immune system by modulating the activities of myeloid cells and T cells. These findings suggest that Th17 cells and their cytokines are a key mediator of cancer development, representing a potential target for cancer therapy. Herein, I review recent preclinical studies on the function of Th17 cells and IL-17 in cancer and discuss possible therapeutic approaches to harness Th17 cells for cancer immunotherapy.

Role of myeloid-derived suppressor cells in immune checkpoint inhibitor therapy in cancer Abstract Over the past decade, immune checkpoint inhibitor (ICI) therapy has demonstrated improved therapeutic efficacy in a wide range of cancers. However, the benefits are restricted to a small population of patients. Therefore, studies on understanding the mechanisms resistant to ICI therapy and for finding predictive biomarkers for ICI therapy are being actively conducted. Recent studies have demonstrated that myeloid-derived suppressor cells (MDSC) inhibit ICI therapy by various mechanisms, and that the response to ICI therapy can be improved by blocking MDSC activity. Moreover, low level of MDSC in patients with cancer has been shown to be correlated with their good prognosis after ICI treatment, thereby suggesting MDSC as a predictive biomarker in this regard. This review focuses on the roles of MDSC in ICI therapy and their relevant applications.

Immunological and clinical implications of immune checkpoint blockade in human cancer Abstract Immune checkpoint inhibitors (ICIs) such as anti-PD-1 and anti-CTLA-4 therapy are now FDA-approved treatment options for different cancer types. However, the therapeutic efficacy of ICIs varies substantially among cancer types and patients, and only a limited proportion of cancer patients benefit clinically from ICIs. To improve the therapeutic efficacy of cancer treatments involving ICI, the mechanisms of response to ICIs and the heterogeneous pattern of immune checkpoint receptor expression need to be better understood. Here, we review recent studies on ICIs in human cancer, providing the necessary basis for the rational design of immunotherapy and for appropriate patient selection.

Transendothelial migration (TEM) of in vitro generated dendritic cell vaccine in cancer immunotherapy Abstract Many efforts have been made to improve the efficacy of dendritic cell (DC) vaccines in DC-based cancer immunotherapy. One of these efforts is to deliver a DC vaccine more efficiently to the regional lymph nodes (rLNs) to induce stronger anti-tumor immunity. Together with chemotaxis, transendothelial migration (TEM) is believed to be a critical and indispensable step for DC vaccine migration to the rLNs after administration. However, the mechanism underlying the in vitro-generated DC TEM in DC-based cancer immunotherapy has been largely unknown. Currently, junctional adhesion molecules (JAMs) were found to play an important role in the TEM of in vitro generated DC vaccines. This paper reviews the TEM of DC vaccines and TEM-associated JAM molecules.

Realgar transforming solution-induced differentiation of NB4 cell by the degradation of PML/RARα partially through the ubiquitin–proteasome pathway Abstract PML/retinoic acid receptor alpha (RARα), as a hallmark of acute promyeloid leukemia (APL), is directly related to the outcome of clinical APL remedy. It is reported that arsenicals can effectively degrade PML/RARα, such as arsenic trioxide and realgar. However, the high toxicity or insolubility have hampered their clinical applications. Realgar transforming solution (RTS) was produced from realgar by bioleaching process in our lab. Previous studies demonstrated that RTS had a significant anti-cancer ability on chronic myeloid leukemia through oncoprotein degradation. The capacity of RTS on treating APL is what is focused on in this study. The results showed that RTS had a noticeable sensitivity in NB4 cell, and RTS remarkably down-regulated PML/RARα expression and induced cell differentiation. Further, RTS could accumulate PML/RARα into the nuclear bodies and then execute degradation, which could be reversed by proteasome inhibitor MG132. The results also exhibited that the reduction of RTS-induced PML/RARα expression accompanied by the elevation of ubiquitin and SUMO-1 protein expression. Finally, PML and SUMO-1 had been demonstrated to be co-localized after RTS treatment by immunofluorescence co-localization assay and immunoprecipitation assay. In conclusion, these results suggested that RTS-induced cell differentiation may attribute to the PML/RARα degradation partially through the ubiquitin–proteasome pathway.

Alexandros Sfakianakis
Anapafseos 5 . Agios Nikolaos
Crete.Greece.72100
2841026182

6948891480

alsfakia@gmail.com