Exosomes are extracellular vesicles secreted by most eukaryotic cells and participate in intercellular communication. The components of exosomes, including proteins, DNA, mRNA, microRNA, long noncoding RNA, circular RNA, etc., which play a crucial role in regulating tumor growth, metastasis, and angiogenesis in the process of cancer development, and can be used as a prognostic marker and/or grading basis for tumor patients. Hereby, we mainly summarized as followed: the role of exosome contents in cancer, focusing on proteins and noncoding RNA; the interaction between exosomes and tumor microenvironment; the mechanisms that epithelial-mesenchymal transition, invasion and migration of tumor affected by exosomes; and tumor suppression strategies based on exosomes. Finally, the application potential of exosomes in clinical tumor diagnosis and therapy is prospected, which providing theoretical supports for using exosomes to serve precise tumor treatment in the clinic.

Substantial growth inhibition and apoptosis without evidence of differentiation were induced in most malignant lymphocytic cells treated with 1-2 microM As2O3. As2O3 may prove useful in the treatment of malignant lymphoproliferative disorders.

BackgroundChimeric antigen receptor (CAR)-engineered T cells have demonstrated promising clinical efficacy in patients with B cell lymphoma. However, the application of CAR-T cell therapy in the treatment of other solid tumors has been limited. We incorporated 4-1BB into the anti-GD2 CAR-T cells to test their cytotoxicity in melanoma in vitro and in vivo. Moreover, we reported the expression of ganglioside GD2 in non-Caucasian melanoma populations for the first time, thus providing a basis for future clinical research.MethodsThis study included tumor samples from 288 melanoma patients at the Peking University Cancer Hospital & Institute. Clinical data were collected. Immunohistochemical assays using antibodies against ganglioside GD2 were performed on formalin-fixed, paraffin-embedded specimens. The ability of ganglioside GD2 CAR-T cells to kill ganglioside GD2+ melanoma cells was evaluated in vitro and in a patient-derived xenograft (PDX) model.ResultsAmong the 288 samples, 49.3% of cases (142/288) demonstrated positive staining with ganglioside GD2. The median survival time in patients exhibiting ganglioside GD2 expression was significantly shorter than that in patients without ganglioside GD2 expression (31 vs. 47.1 months, P < 0.001). In the present study, CAR was constructed using a GD2-specific scFv (14.G2a), T cell receptor CD3ζ chain, and the CD137 (4-1BB) costimulatory motif. In addition, the GD2.BBζ CAR-T cells demonstrated specific lysis of ganglioside GD2-expressing melanoma cells in vitro. In two PDX models, mice that received intravenous or local intratumor injections of GD2.BBζ CAR-T cells experienced rapid tumor regression.ConclusionsThese data demonstrate that the rate of GD2 expression in Chinese patients is 49.3%. GD2.BBζ CAR-T cells can both efficiently lyse melanoma in a GD2-specific manner and release Th1 cytokines in an antigen-dependent manner in vitro and in vivo. Anti-GD2/4-1BB CAR-T cells represent a clinically appealing treatment strategy for Chinese melanoma patients exhibiting GD2 expression and provide a basis for future studies of the clinical application of immunotherapy for melanoma.Electronic supplementary materialThe online version of this article (10.1186/s13045-017-0548-2) contains supplementary material, which is available to authorized users.

Low concentrations of As2O3 (≤1 μmol/L) induce long-lasting remission in patients with acute promyelocytic leukemia (APL) without significant myelosuppressive side effects. Several groups, including ours, have shown that 0.5 to 1 μmol/L As2O3 induces apoptosis in APL-derived NB4 cells, whereas other leukemic cells are resistant to As2O3 or undergo apoptosis only in response to greater than 2 μmol/L As2O3. In this report, we show that the ability of As2O3 to induce apoptosis in leukemic cells is dependent on the activity of the enzymes that regulate cellular H2O2 content. Thus, NB4 cells have relatively low levels of glutathione peroxidase (GPx) and catalase and have a constitutively higher H2O2content than U937 monocytic leukemia cells. Glutathione-S-transferase π (GSTπ), which is important for cellular efflux of As2O3, is also low in NB4 cells. Moreover, As2O3 further inhibits GPX activity and increases cellular H2O2 content in NB4 but not in U937 cells. Selenite pretreatment of NB4 cells increases the activity of GPX, lowers cellular H2O2 levels, and renders NB4 cells resistant to 1 μmol/L As2O3. In contrast, concentrations of As2O3 that alone are not capable of inducing apoptosis in NB4 cells induce apoptosis in the presence of the GPx inhibitor mercaptosuccinic acid. Similar effects are observed by modulating the activity of catalase with its inhibitor, aminotriazol. More important from a therapeutic point of view, U937 and HL-60 cells, which require high concentrations of As2O3 to undergo apoptosis, become sensitive to low, clinically acceptable concentrations of As2O3 when cotreated with these GPx and catalase inhibitors. The induction of apoptosis by As2O3 involves an early decrease in cellular mitochondrial membrane potential and increase in H2O2 content, followed by cytochrome c release, caspase 3 activation, DNA fragmentation, and the classic morphologic changes of apoptosis.

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Arsenic trioxide (As2O3) induces clinical remission in acute promyelocytic leukemia (APL) with minimal toxicity and apoptosis in APL-derived NB4 cells at low (1 to 2 μmol/L) concentration. We examined the basis for NB4 cell sensitivity to As2O3 to identify experimental conditions that would render other malignant cells responsive to low concentrations of As2O3. The intracellular glutathione (GSH) content had a decisive effect on As2O3-induced apoptosis. Highly sensitive NB4 cells had the lowest GSH and the sensitivity of other cell lines was inversely proportional to their GSH content. The t(14;18) B-cell lymphoma cell line had low GSH levels and sensitivity to As2O3 at levels slightly higher than in APL cells. Experimental upmodulation of GSH content decreased the sensitivity to As2O3. Ascorbic acid and buthionine sulfoxide (BSO) decreased GSH to a greater extent, and rendered malignant cells more sensitive to As2O3. As2O3-induced apoptosis was not enhanced by ascorbic acid in normal cells, suggesting that the combination of ascorbic acid and As2O3may be selectively toxic to some malignant cells. Ascorbic acid enhanced the antilymphoma effect of As2O3 in vivo without additional toxicity. Thus, As2O3alone or administered with ascorbic acid may provide a novel therapy for lymphoma.

PURPOSE Metastatic mucosal melanoma responds poorly to anti–programmed cell death-1 (PD-1) monotherapy. Vascular endothelial growth factor (VEGF) has been shown to play an important immunosuppressive role in the tumor microenvironment. The combination of VEGF inhibition and PD-1 blockade provides therapeutic opportunities for patients refractory to either therapy alone. PATIENTS AND METHODS We conducted a single-center, phase IB trial evaluating the safety and preliminary efficacy of toripalimab, a humanized immunoglobulin G4 monoclonal antibody against PD-1 in combination with the VEGF receptor inhibitor axitinib in patients with advanced melanoma, including patients with chemotherapy-naïve mucosal melanomas (88%). Patients received toripalimab at 1 or 3 mg/kg via intravenous infusion every 2 weeks, in combination with axitinib 5 mg orally twice a day, in a dose-escalation and cohort-expansion study until confirmed disease progression, unacceptable toxicity, or voluntary withdrawal. The primary objective was safety. Secondary objectives included efficacy, pharmacokinetics, pharmacodynamics, immunogenicity, and tumor tissue biomarkers. RESULTS Thirty-three patients were enrolled. No dose-limiting toxicities were observed. Ninety-seven percent of patients experienced treatment-related adverse events (TRAEs). The most common TRAEs were mild (grade 1 or 2) and included diarrhea, proteinuria, hand and foot syndrome, fatigue, AST or ALT elevation, hypertension, hypo- or hyperthyroidism, and rash. Grade 3 or greater TRAEs occurred in 39.4% of patients. By the cutoff date, among 29 patients with chemotherapy-naïve mucosal melanoma, 14 patients (48.3%; 95% CI, 29.4% to 67.5%) achieved objective response, and the median progression-free survival time was 7.5 months (95% CI, 3.7 months to not reached) per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. CONCLUSION The combination of toripalimab plus axitinib was tolerable and showed promising antitumor activity in patients with treatment-naïve metastatic mucosal melanoma. Patients enrolled in this study were all Asian, and this combination therapy must be validated in a randomized phase III trial that includes a non-Asian population before it can become a standard of care.

BackgroundJS001, a humanized IgG4 monoclonal antibody against the programmed death-1 (PD-1) receptor, blocks the interaction of PD-1 with its ligands and promotes T cell activation in preclinical studies. This phase I study is designed to evaluate the safety, tolerability, and clinical activity of JS001 in advanced melanoma or urologic cancer patients who are refractory to standard systemic therapy.Patients and methodsIn the dose escalation cohorts, subjects initially received a single-dose, intravenous infusion of JS001, and were followed for 28 days followed by multi-dose infusions every 2 weeks. In the dose expansion cohorts, subjects received multi-dose infusions every 2 weeks. Clinical response was evaluated after each 8-week treatment cycle according to RECIST v1.1 criteria.ResultsThirty-six subjects diagnosed with advanced melanoma (n = 22), urothelial cancer (UC) (n = 8), or renal cell cancer (RCC) (n = 6) were enrolled. Melanoma subjects included 14 acral and 4 mucosal subtypes. JS001 was well tolerated, and no dose-limiting toxicity was observed. By the safety data cutoff date, 100% of subjects had treatment-related adverse events (TRAE) with most adverse events being grade 1 or 2, and ≥ grade 3 TRAEs occurred in 36%. Among all 36 subjects, 1 confirmed complete response (acral melanoma), 7 confirmed partial responses (2 acral melanoma, 1 mucosal melanoma, 2 UC, and 2 RCC), and 10 stable disease were observed, for an objective response rate of 22.2% (95% CI, 10.1 to 39.2), and a disease control rate of 50.0% (95% CI, 32.9 to 67.1). Clinical responses were correlated with PD-L1 expression on tumor cells, the presence of tumor infiltrating lymphocytes (TIL), baseline tumor volume, ECOG performance status, serum LDH levels, high percentage of activated CD8+ T cells and CD3− CD16+ CD54+ NK cells in the peripheral blood as well as tumor mutational burden (TMB).ConclusionJS001 was well tolerated and demonstrated promising anti-tumor activity in UC and RCC as well as in previously underexplored acral and mucosal melanoma subtypes. Subjects with an immune-active profile in the tumor microenvironment or in peripheral blood responded favorably to JS001 treatment. The completion of the current phase I study has led to the initiation of the first prospective anti-PD-1 registration trial in Asia focusing on acral and mucosal melanoma subtypes, representative of the regional disease epidemiology.Trial registrationClinical Trial ID: NCT02836795, registered July 19, 2016, retrospectively registered.Electronic supplementary materialThe online version of this article (10.1186/s13045-018-0693-2) contains supplementary material, which is available to authorized users.