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γδ‐T cells are innate‐like T cells with dual antitumor activities. They can directly eradicate tumor cells and function as immunostimulatory cells to promote antitumor immunity. Previous studies have demonstrated that small extracellular vesicles (EVs) derived from γδ‐T cells (γδ‐T‐EVs) inherited the dual antitumor activities from their parental cells. However, it remains unknown whether γδ‐T‐EVs can be designed as tumors vaccine to improve therapeutic efficacy. Here, we found that γδ‐T‐EVs had immune adjuvant effects on antigen‐presenting cells, as revealed by enhanced expression of antigen‐presenting and co‐stimulatory molecules, secretion of pro‐inflammatory cytokines and antigen‐presenting ability of DCs after γδ‐T‐EVs treatment. The γδ‐T‐EVs‐based vaccine was designed by loading tumor‐associated antigens (TAAs) into γδ‐T‐EVs. Compared with γδ‐T‐EVs, the γδ‐T‐EVs‐based vaccine effectively promoted more tumor‐specific T‐cell responses. In addition, the vaccine regimen preserved direct antitumor effects and induced tumor cell apoptosis. Interestingly, the allogeneic γδ‐T‐EVs‐based vaccine showed comparable preventive and therapeutic antitumor effects to their autologous counterparts, indicating a better way of centralization and standardization in clinical practice. Furthermore, the allogeneic γδ‐T‐EVs‐based vaccine displayed advantages over the DC‐EVs‐based vaccine through their dual antitumor activities. This study provides a proof‐of‐concept for using the allogeneic γδ‐T‐EVs‐based vaccine in cancer control.

Cancer is caused by uncontrollable growth of neoplastic cells, leading to invasion of adjacent and distant tissues resulting in death. Cancer cells have specific nutrient(s) auxotrophy and have a much higher nutrient demand compared to normal tissues. Therefore, different metabolic inhibitors or nutrient-depleting enzymes have been tested for their anti-cancer activities. We review recent available laboratory and clinical data on using various specific amino acid metabolic pathways inhibitors in treating cancers. Our focus is on glutamine, asparagine, and arginine starvation. These three amino acids are chosen due to their better scientific evidence compared to other related approaches in cancer treatment. Amino acid-specific depleting enzymes have been adopted in different standard chemotherapy protocols. Glutamine starvation by glutaminase inhibitior, transporter inhibitor, or glutamine depletion has shown to have significant anti-cancer effect in pre-clinical studies. Currently, glutaminase inhibitor is under clinical trial for testing anti-cancer efficacy. Clinical data suggests that asparagine depletion is effective in treating hematologic malignancies even as a single agent. On the other hand, arginine depletion has lower toxicity profile and can effectively reduce the level of pro-cancer biochemicals in patients as shown by ours and others’ data. This supports the clinical use of arginine depletion as anti-cancer therapy but its exact efficacy in various cancers requires further investigation. However, clinical application of these enzymes is usually hindered by common problems including allergy to these foreign proteins, off-target cytotoxicity, short half-life and rapidly emerging chemoresistance. There have been efforts to overcome these problems by modifying the drugs in different ways to circumvent these hindrance such as (1) isolate human native enzymes to reduce allergy, (2) isolate enzyme isoforms with higher specificities and efficiencies, (3) pegylate the enzymes to reduce allergy and prolong the half-lives, and (4) design drug combinations protocols to enhance the efficacy of chemotherapy by drug synergy and minimizing resistance. These improvements can potentially lead to the development of more effective anti-cancer treatment with less adverse effects and higher therapeutic efficacy.

Neuroblastoma is one of the few childhood cancers that carries a tumor-specific antigen in the form of a glycolipid antigen known as GD2. It has restricted expression in normal tissue, such as peripheral afferent nerves. Monoclonal antibodies targeting GD2 have been applied clinically to high-risk neuroblastoma with significant success. However, there are different anti-GD2 products and administration regimens. For example, anti-GD2 has been used in combination with chemotherapy during the induction phase or with retinoic acid during the maintenance stage. Regimens also vary in the choice of whether to add cytokines (i.e., IL-2, GMCSF, or both). Furthermore, the addition of an immune enhancer, such as β-glucan, or allogeneic natural killer cells also becomes a confounder in the interpretation. The question concerning which product or method of administration is superior remains to be determined. So far, most studies agree that adding anti-GD2 to the conventional treatment protocol can achieve better short- to intermediate-term event-free and overall survival, but the long-term efficacy remains to be verified. How to improve its efficacy is another challenge. Late relapse and central nervous system metastasis have emerged as new problems. The methods to overcome the mechanisms related to immune evasion or resistance to immunotherapy represent new challenges to be resolved. The newer anti-GD2 strategies, such as bispecific antibody linking of anti-GD2 with activated T cells or chimeric antigen receptor T cells, are currently under clinical trials, and they may become promising alternatives. The use of anti-GD2/GD3 tumor vaccine is a novel and potential approach to minimizing late relapse. How to induce GD2 expression from tumor cells using the epigenetic approach is a hot topic nowadays. We expect that anti-GD2 treatment can serve as a model for the use of monoclonal antibody immunotherapy against cancers in the future.

Immunotherapy with the chimeric anti-GD2 monoclonal antibody dinutuximab, combined with alternating granulocyte-macrophage colony-stimulating factor and intravenous interleukin-2 (IL-2), improves survival in patients with high-risk neuroblastoma. We aimed to assess event-free survival after treatment with ch14.18/CHO (dinutuximab beta) and subcutaneous IL-2, compared with dinutuximab beta alone in children and young people with high-risk neuroblastoma. We did an international, open-label, phase 3, randomised, controlled trial in patients with high-risk neuroblastoma at 104 institutions in 12 countries. Eligible patients were aged 1–20 years and had MYCN-amplified neuroblastoma with stages 2, 3, or 4S, or stage 4 neuroblastoma of any MYCN status, according to the International Neuroblastoma Staging System. Patients were eligible if they had been enrolled at diagnosis in the HR-NBL1/SIOPEN trial, had completed the multidrug induction regimen (cisplatin, carboplatin, cyclophosphamide, vincristine, and etoposide, with or without topotecan, vincristine, and doxorubicin), had achieved a disease response that fulfilled prespecified criteria, had received high-dose therapy (busulfan and melphalan or carboplatin, etoposide, and melphalan) and had received radiotherapy to the primary tumour site. In this component of the trial, patients were randomly assigned (1:1) to receive dinutuximab beta (20 mg/m2 per day as an 8 h infusion for 5 consecutive days) or dinutuximab beta plus subcutaneous IL-2 (6 × 106 IU/m2 per day on days 1–5 and days 8–12 of each cycle) with the minimisation method to balance randomisation for national groups and type of high-dose therapy. All participants received oral isotretinoin (160 mg/m2 per day for 2 weeks) before the first immunotherapy cycle and after each immunotherapy cycle, for six cycles. The primary endpoint was 3-year event-free survival, analysed by intention to treat. This trial was registered with ClinicalTrials.gov, number NCT01704716, and EudraCT, number 2006-001489-17, and recruitment to this randomisation is closed. Between Oct 22, 2009, and Aug 12, 2013, 422 patients were eligible to participate in the immunotherapy randomisation, of whom 406 (96%) were randomly assigned to a treatment group (n=200 to dinutuximab beta and n=206 to dinutuximab beta with subcutaneous IL-2). Median follow-up was 4·7 years (IQR 3·9–5·3). Because of toxicity, 117 (62%) of 188 patients assigned to dinutuximab beta and subcutaneous IL-2 received their allocated treatment, by contrast with 160 (87%) of 183 patients who received dinutuximab beta alone (p<0·0001). 3-year event-free survival was 56% (95% CI 49–63) with dinutuximab beta (83 patients had an event) and 60% (53–66) with dinutuximab beta and subcutaneous IL-2 (80 patients had an event; p=0·76). Four patients died of toxicity (n=2 in each group); one patient in each group while receiving immunotherapy (n=1 congestive heart failure and pulmonary hypertension due to capillary leak syndrome; n=1 infection-related acute respiratory distress syndrome), and one patient in each group after five cycles of immunotherapy (n=1 fungal infection and multi-organ failure; n=1 pulmonary fibrosis). The most common grade 3–4 adverse events were hypersensitivity reactions (19 [10%] of 185 patients in the dinutuximab beta group vs 39 [20%] of 191 patients in the dinutuximab plus subcutaneous IL-2 group), capillary leak (five [4%] of 119 vs 19 [15%] of 125), fever (25 [14%] of 185 vs 76 [40%] of 190), infection (47 [25%] of 185 vs 64 [33%] of 191), immunotherapy-related pain (19 [16%] of 122 vs 32 [26%] of 124), and impaired general condition (30 [16%] of 185 vs 78 [41%] of 192). There is no evidence that addition of subcutaneous IL-2 to immunotherapy with dinutuximab beta, given as an 8 h infusion, improved outcomes in patients with high-risk neuroblastoma who had responded to standard induction and consolidation treatment. Subcutaneous IL-2 with dinutuximab beta was associated with greater toxicity than dinutuximab beta alone. Dinutuximab beta and isotretinoin without subcutaneous IL-2 should thus be considered the standard of care until results of ongoing randomised trials using a modified schedule of dinutuximab beta and subcutaneous IL-2 are available. European Commission 5th Frame Work Grant, St. Anna Kinderkrebsforschung, Fondation ARC pour la recherche sur le Cancer.

Natural killer group 2 D (NKG2D) receptor, one of the activation receptors on NK cells, has gained increasing attention in recent years because its ligands are widely expressed in most cancers. Naturally, NKG2D reacts to 8 different stress-induced ligands, MICA/B, and ULBP1-6. Despite being genomically conserved between human and mouse, NKG2D transcripts have splice variants that can differentiate the two. hNKG2D or mNKG2D (both long and short transcripts) interacts with DAP10 only in human but DAP10/12 in mouse, switching on different effector functions such as IFN-γ production and cytotoxicity. Full-length, extracellular or cytoplasmic domains have been used to construct chimeric antigen receptors (CAR) or implement into the antibody structures including bispecific antibodies. Interestingly, most of the NKG2D CARs, either on T cells or NK cells are investigated in preclinical models of solid tumors. In this article, we reviewed the majority of published NKG2D-based CAR and antibody designs, comparing their respective advantages and disadvantages. We also elaborated how these CARs and antibodies were tested in preclinical cancer models and clinical trials in this review article.

Pulmonary fibrosis is a chronic progressive lung disease with few treatments. Human mesenchymal stem cells (MSCs) have been shown to be beneficial in pulmonary fibrosis because they have immunomodulatory capacity. However, there is no reliable model to test the therapeutic effect of human MSCs in vivo. To mimic pulmonary fibrosis in humans, we established a novel bleomycin-induced pulmonary fibrosis model in humanized mice. With this model, the benefit of human MSCs in pulmonary fibrosis and the underlying mechanisms were investigated. In addition, the relevant parameters in patients with pulmonary fibrosis were examined. We demonstrate that human CD8 T cells were critical for the induction of pulmonary fibrosis in humanized mice. Human MSCs could alleviate pulmonary fibrosis and improve lung function by suppressing bleomycin-induced human T-cell infiltration and proinflammatory cytokine production in the lungs of humanized mice. Importantly, alleviation of pulmonary fibrosis by human MSCs was mediated by the PD-1/programmed death-ligand 1 pathway. Moreover, abnormal PD-1 expression was found in circulating T cells and lung tissues of patients with pulmonary fibrosis. Our study supports the potential benefit of targeting the PD-1/programmed death-ligand 1 pathway in the treatment of pulmonary fibrosis.

The gold standard of cancer diagnosis has long been based on histological characteristics. With the rapid advancement of genetic medicine, such standard algorithm of diagnostic approach is facing a challenge. The genetic findings have been changed from being a “supporting character” into the role of a “main character”. More and more disease diagnosis and classification has to be defined by genetic basis. In this article, we focus on the challenges in the field of pediatric oncology. We cited 2 scenarios where genetic information plays a pivotal role in identifying the underlying pathology. The first scenario is that same genetic mutation can lead to variable clinical phenotypes, this includes EWSR1‐PATZ1 fusion related neoplasms; BCOR neoplasms; and GATA‐2 deficiency related immunodeficiency and myelodysplastic syndrome. Another scenario is relatively more common that is the same clinical and histopathological phenotype with different underlying genotypes. The genotypes actually impact on the treatment response and outcome. We used medulloblastoma as an example. In fact, we can also find similar scenario in many pediatric cancers such as Ewing sarcoma, ependymoma, etc. The essence of this article is to remind clinicians of the rapid development in genetic medicine and it has been reshaping the landscape of the modern disease classification and therapeutic approach. In the near future, it may even lead to a paradigm shift in our disease diagnostic algorithm. Possible paradigm shift in the algorithm for childhood cancer management.

Central nervous system (CNS) tumors represent the most deadly cancer in pediatric age group. In China, thousands of children are diagnosed with CNS tumors every year. Despite the improving socioeconomic status and availability of medical expertise within the country, unique challenges remain for the delivery of pediatric neuro‐oncology service. In this review, we discuss the existing hurdles for improving the outcome of children with CNS tumors in China. Need for precise disease burden estimation, lack of intra‐ and inter‐hospital collaborative networks, high probability of treatment abandonment, along with financial toxicities from treatment represent the key challenges that Chinese healthcare providers encounter. The tremendous opportunities for advancing the status of pediatric neuro‐oncology care in and beyond the country are explored.

Glutathione and multidrug resistance protein (MRP) play an important role on the metabolism of a variety of drugs. Bismuth drugs have been used to treat gastrointestinal disorder and Helicobacter pylori infection for decades without exerting acute toxicity. They were found to interact with a wide variety of biomolecules, but the major metabolic pathway remains unknown. For the first time (to our knowledge), we systematically and quantitatively studied the metabolism of bismuth in human cells. Our data demonstrated that over 90% of bismuth was passively absorbed, conjugated to glutathione, and transported into vesicles by MRP transporter. Mathematical modeling of the system reveals an interesting phenomenon. Passively absorbed bismuth consumes intracellular glutathione, which therefore activates de novo biosynthesis of glutathione. Reciprocally, sequestration by glutathione facilitates the passive uptake of bismuth and thus completes a self-sustaining positive feedback circle. This mechanism robustly removes bismuth from both intra- and extracellular space, protecting critical systems of human body from acute toxicity. It elucidates the selectivity of bismuth drugs between human and pathogens that lack of glutathione, such as Helicobacter pylori , opening new horizons for further drug development. Significance Bismuth compounds have long been used in clinic for the treatment of various diseases, in particular, for Helicobacter pylori infection. We reported the mechanism of uptake of bismuth compounds by mammalian cells and bacteria, and demonstrated a passive transport of the metallodrug. We showed that glutathione and multidrug resistance protein transporter mediate a self-propelled disposal of bismuth antiulcer drug. A model was derived to elucidate the uptake of the metallodrug, and which may readily be extended to other drugs or drug candidates. Our work uncovered the secret of low toxicity of bismuth in human and relatively high drug selectivity against “glutathione-poor” pathogens such as H. pylori .

Background Majority of neuroblastoma patients develop metastatic disease at diagnosis and their prognosis is poor with current therapeutic approach. Major challenges are how to tackle the mechanisms responsible for tumorigenesis and metastasis. Human mesenchymal stem cells (hMSCs) may be actively involved in the constitution of cancer microenvironment. Methods An orthotopic neuroblastoma murine model was utilized to mimic the clinical scenario. Human neuroblastoma cell line SK-N-LP was transfected with luciferase gene, which were inoculated with/without hMSCs into the adrenal area of SCID-beige mice. The growth and metastasis of neuroblastoma was observed by using Xenogen IVIS 100 in vivo imaging and evaluating gross tumors ex vivo. The homing of hMSCs towards tumor was analyzed by tracing fluorescence signal tagged on hMSCs using CRI Maestro™ imaging system. Results hMSCs mixed with neuroblastoma cells significantly accelerated tumor growth and apparently enhanced metastasis of neuroblastoma in vivo. hMSCs could be recruited by primary tumor and also become part of the tumor microenvironment in the metastatic lesion. The metastatic potential was consistently reduced in lung and tumor when hMSCs were pre-treated with stromal cell derived factor-1 (SDF-1) blocker, AMD3100, suggesting that the SDF-1/CXCR4 axis was one of the prime movers in the metastatic process. Conclusions hMSCs accelerated and facilitated tumor formation, growth and metastasis. Furthermore, the homing propensity of hMSCs towards both primary tumor and metastatic loci can also provide new therapeutic insights in utilizing bio-engineered hMSCs as vehicles for targeted anti-cancer therapy.