Latest ArticlesIn recent years, the role of ketone body metabolism in tumor growth, invasion and metastasis has attracted much attention. Succinyl-CoA transferase (SCOT) is a key enzyme in the metabolism of ketone bodies. Its function is to transfer the coenzyme A group of succinyl-CoA to acetoacetate and catalyze the formation of acetoacetyl-CoA, which is the first rate-limiting step in ketone metabolism. Then acetoacetyl-CoA further breaks into two molecules of acetyl-CoA and enters the tricarboxylic acid cycle. Studies have shown that SCOT is highly expressed in a variety of tumors, and is closely related to tumor progression and prognosis of patients, which makes SCOT a potential marker for clinical diagnosis and prognosis evaluation; in addition, inhibition of SCOT activity can hinder the metabolism of ketone bodies in tumor cells, that is, reduce the production of ATP, thereby inhibiting tumor growth, proliferation, invasion and metastasis. This review aims to explore the important role of SCOT in metabolic pathways and its relationship with tumorigenesis and development, and to provide new ideas for exploring tumor metabolism and targeting molecular drugs.
Post-translational modifications (PTMs) of proteins is an important mode of protein function regulation, which is essential for the structure and function of proteins under physiological and pathological conditions, and the types of modifications is wide. Cancer immunotherapy refers to an effective method for cancer treatment by activating or normalizing disabled immune cells. In recent years, researchers have found that many types of PTM are involved in the process of proliferation, activation and metabolic reprogramming of immune cells in cancer microenvironment, and may affect the efficacy of cancer immunotherapy. Therefore, this article reviews the effects of several different PTMs on immune cells in cancer microenvironment, and aims to provide new ideas for cancer immunotherapy.
Distinct from conventional cancer therapies focusing directly on local tumors, cancer immunotherapy aims to restore or enhance immune surveillance to fight against cancer, which bears the advantages of less side effects, lasting efficacy, substantial specificity and suitability for individualized treatment. As the most powerful antigen-presenting cell type, dendritic cells (DCs) can induce potent antigen-specific immune responses in vivo. DCs-based immunotherapy acts by loading DCs with cancer antigens in various ways to elicit specific anti-tumor immune responses. Currently, pulsing DCs with cancer antigen encoding mRNAs is an antigen loading approach under extensive study, registering encouraging results in relevant immunotherapeutic clinical trials. Thus, pulsing DCs with mRNAs is a new and highly promising modality in cancer immunotherapy.
Chemotherapeutic agents, also known as cytotoxic anticancer agents, inhibit the cancer cell proliferation via interrupting DNA replication, transcription and microtubule stability etc. Chemotherapeutic agents have been used in clinical cancer treatment for decades. Recently, with the tremendous advancement in immunooncology, chemotherapeutic agents have aroused renewed interest for their great potential to sensitize tumor cells to immunotherapy. Meanwhile, it is worth noting that the effects of chemotherapeutic agents on the immune system involve multiple aspects with complex mechanisms. Currently, there still lacks guidance for the combined use of chemotherapy and immunotherapy, and the clinical benefits remain obscure, impelling a better under-standing of the impact of chemotherapeutic agents on the antitumor immunity. This article reviews the mechanistic insights into chemotherapy-modulated antitumor immune responses, with major focus on the direct effect on immune cells and the immunogenic remodeling of tumor cells. The review is particularly interested in the chemo-therapy-trigged signaling that contributes to the immunogenic cell death. This review may provide useful insights into the immunomodulatory effects of chemotherapeutic agents and the implications in exploring therapeutic oppor-tunities of chemotherapy in cancer immunotherapy.
N6-methyladenosine (m6A) modification is one of the most common modifications of eukaryotic mRNA, and has become a hotspot in the field of life sciences in recent years. m6A modification is dynamically reversible in mammalian cells and regulated by m6A methyltransferase (writers), demethylase (erasers), and "reader" proteins. m6A can regulate various biological processes of mRNA such as RNA splicing, nuclear export, protein translation and degradation. Recent studies indicated that m6A is important for the initiation and development of cancer. The present review summarized biological functions of m6A on mRNA and discussed its roles in cell proliferation, migration, invasion, cell mentalism, and angiogenesis. Further, the m6A can regulate the development of various cancers including acute myelocytic leukemia (AML), breast, liver and colorectal cancer. Nowadays, the inhibitors of m6A related enzymes including fat-mass and obesity-associated protein and AlkB homolog 5 are being developed. We further discussed the potential values of m6A and its related targets on cancer therapy and treatment.
Although numbers of naked antibodies showing clinical efficacy as single agents, their therapeutic effect is limited. Chemotherapy is very effective but with relatively large side effects, so conjugation of small chemotherapeutic drugs to antibodies is one of the important methods to enhance therapeutic potential of antibodies. Antibody-drug conjugates (ADCs) represent a promising therapeutic approach for cancer patients by combining the antigen-targeting specificity of monoclonal antibodies (mAbs) with the cytotoxic potency of chemotherapeutic drugs. These modified antibodies are expected to selectively deliver chemotherapeutic drugs to tumor cells and provide sustained clinical benefit to cancer patients, at the same time, minimizing systemic toxicity. ADCs are expected to bring together the benefits of highly potent drugs on the one hand and selective binders of specific tumor antigens on the other hand. However, designing an ADC is very complex, requiring thoughtful combination of antibody, linker, and payload drugs in the context of a target and a defined cancer indication. Although many challenges remain, recent clinical success has generated intense interest in this therapeutic class.
Programmed cell death protein 1 (PD-1) is an important immunosuppressive molecule, which combines with programmed cell death 1 ligand 1 (PD-L1) to initiate programmed T-cell death, leading to immune escape of tumor cells. Immune checkpoint inhibitors kill tumor cells by blocking the binding of PD-1 to PD-L1 and reactivating the patient's own immune system. With the approval of anti-PD-1 monoclonal antibodies nivolumab, pembrolizumab and anti-PD-L1 monoclonal antibody atezolizumab by FDA for the treatment of melanoma, advanced non-small cell lung cancer and other cancers, cancer treatment has ushered in a new dawn. However, only 20% of patients achieved long-term efficacy after treatment, and most patients relapsed later. Therefore, it is significant to identify effective biomarkers and develop new targets to improve the response of patients to immuno-therapy. This article reviews on the mechanism of action of anti-PD-1/PD-L1 drugs in tumors, potential biomarkers and the mechanism of acquired drug resistance, as well as combination therapy under research.
Carnitine palmitoyltransferase 1 (CPT1) is a fatty acid β-oxidative rate-limiting enzyme of fatty acid β-oxidation (FAO) present in the outer membrane of mitochondria, which is closely related to metabolic diseases and tumors. Numerous studies have shown that various subtypes of CPT1 are abnormally expressed in cancer cells and play an important role in resistance to metabolic stress. With the development of tumor immunotherapy, its role in immune cells and organs has also attracted attention. This article aims to review the biological functions of CPT1 and the role of different subtypes in tumor metabolism and immune regulation, and the research progress of its inhibitors, providing new ideas for cancer treatment.
The occurrence and development of tumors are closely related to the tumor microenvironment. Among them, tumor immune microenvironment and tumor metabolic microenvironment play important roles in tumor. Tumor immunotherapy is a way to kill tumor cells by activating the body's immune system. Tumor immuno-therapy has shown good therapeutic effects in a variety of solid tumors. In recent years, significant progress has been made in tumor immunotherapy. The Warburg effect indicates that tumor cells use aerobic glycolysis to acquire energy. In the tumor, the energy metabolism pathway is abnormal, and the tumor microenvironment can induce the reprogramming of tumor cell metabolism. Therefore, targeting tumor metabolism is also of great signifi-cance for tumor treatment. In this paper, we reviewed the research progress of drug targets related to tumor immu-nology and tumor metabolism in recent years, as well as the progress of drug development.
Immunotherapy has emerged as one of the major modalities for clinical cancer therapy, along with surgery, chemotherapy, radiotherapy and targeted therapy. However, tumor-targeted delivery of immune therapeutics is challenged by a series of barriers including non-specific release, poor tumor penetration capacity, and insufficient cellular uptake of the therapeutic regimens, which seriously restricted the efficiency and efficacy of immunotherapy. To address above challenges, nanosized drug delivery systems (NDDS) have been extensively exploited to achieve tumor-targeted delivery of immunotherapy drugs. It has been well investigated that solid tumors are of unique characteristics including acidic, hypoxic and enzymatic extracellular microenvironment. Meanwhile, the tumor cells are of acidic, reductant and reactive oxygen species intracellular microenvironment. In recent years, a large variety of tumor microenvironment-activatable NDDS have been exploited to respond specifically to the stimulus of extracellular or intracellular tumor microenvironment for enhancing the accumulation, retention and penetration in the tumor tissue. These NDDS were also employed to promote intracellular uptake and tunable drug release inside the tumor cells. In this review article, we summarized the recent progress of our laboratory using the tumor microenvironment-activatable NDDS for immune efficient therapeutics delivery, and improved cancer immunotherapy. We also briefly discussed the challenges and provided perspective of NDDS-based cancer immunotherapy.