Sanguisorbae Radix Suppresses Colorectal Tumor Growth Through PD-1/PD-L1 Blockade and Synergistic Effect With Pembrolizumab in a Humanized PD-L1-Expressing Colorectal Cancer Mouse Model.

Immune checkpoints such as programmed death-1 (PD-1) have been proven as antitumor targets by enhancing cytotoxic T cell activity. All immune checkpoint blockades are antibody therapeutics that have large size and high affinity, as well as known immune-related side effects and low responses. To overcome the limitation of antibody therapeutics, we have explored PD-1/PD-L1 (programmed death-ligand 1) blockades in traditional oriental medicine, which has a long history but has not yet studied PD-1/PD-L1 blockades. Sanguisorbae Radix extract (SRE) blocked PD-1 and PD-L1 binding in competitive ELISA. SRE effectively inhibited the PD-1/PD-L1 interaction, thereby improving T cell receptor (TCR) signaling and the NFAT-mediated luciferase activity of T cells. SRE treatment reduced tumor growth in the humanized PD-L1 MC38 cell allograft humanized PD-1 mouse model. Additionally, the combination of SRE and pembrolizumab (anti-PD-1 antibody) suppressed tumor growth and increased infiltrated cytotoxic T cells to a greater extent did either agent alone. This study showed that SRE alone has anticancer effects via PD-1/PD-L1 blockade and that the combination therapy of SRE and pembrolizumab has enhanced immuno-oncologic effects.

Tumor microenvironment-adjusted prognostic implications of the KRAS mutation subtype in patients with stage III colorectal cancer treated with adjuvant FOLFOX.

Several studies have reported that the prognostic effect of KRAS mutations on colorectal cancers (CRCs) varies depending on the type of mutation. Considering the effect of KRAS mutations on tumor microenvironment, we analyzed the prognostic significance of KRAS mutation types after adjusting for the tumor-infiltrating lymphocytes (TIL) and tumor-stromal percentage (TSP) statuses. In two independent cohorts, KRAS mutations were analyzed by Sanger sequencing and/or next-generation sequencing. TIL density and the TSP were quantified from whole-slide immunohistochemical images. KRAS-mutant CRCs were divided into three subgroups (G12D/V, other codon 12 mutations and codon 13 mutations) to examine their differential effect on TIL density, the TSP and recurrence-free survival (RFS). Among the KRAS mutations, only the G12D/V subgroups showed significantly less TIL infiltration than the wild-type CRCs. According to survival analysis, G12D/V mutations were associated with short RFS; codon 13 mutations showed discordant trends in the two cohorts, and other codon 12 mutations showed no significant association. Multivariate analysis further supported the prognostic value of G12D/V mutations. This result is not only consistent with a recent study suggesting the immunosuppressive effect of mutant KRAS but also provides insight into the type-specific prognostic effect of KRAS mutations.

Discovery of 4-Arylindolines Containing a Thiazole Moiety as Potential Antitumor Agents Inhibiting the Programmed Cell Death-1/Programmed Cell Death-Ligand 1 Interaction.

Through specific structural modification of a 4-phenylindoline precursor, new 4-arylindolines containing a thiazole moiety were developed and found to be promising modulators of the programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) axis. Compound A30 exhibited outstanding biochemical activity, with an IC50 of 11.2 nM in a homogeneous time-resolved fluorescence assay. In the cell-based assay, A30 significantly promoted IFN-γ secretion and rescued T-cell proliferation, which were inhibited by PD-1 activation. Furthermore, A30 showed favorable in vivo antitumor activity in a mouse 4T1 breast carcinoma model. Moreover, in mouse CT26 colon carcinoma models, A30 potently suppressed the growth of CT26/PD-L1 tumor but did not obviously affect the growth of CT26/vector tumor. The results of flow cytometry analysis indicated that A30 inhibited tumor growth by activating the immune microenvironment. We concluded that A30 is a new starting point for further development of PD-1/PD-L1 interaction inhibitors as antitumor agents.

ICAM-1 orchestrates the abscopal effect of tumor radiotherapy.

Compelling evidence indicates that radiotherapy (RT) has a systemic inhibitory effect on nonirradiated lesions (abscopal effect) in addition to the ablation of irradiated tumors. However, this effect occurs only in rare circumstances in clinical practice, and mechanisms underlying the abscopal effect of RT are neither fully understood nor therapeutically utilized. Here we identified that intercellular adhesion molecule-1 (ICAM-1), an inducible glycoprotein of the immunoglobulin superfamily, is up-regulated in nonirradiated tumors responsive to RT. ICAM-1 expression in preclinical animal models can be noninvasively detected by optical imaging and positron emission tomography (PET) using near-infrared fluorescence dye- and 64Cu-labeled imaging probes that we synthesized, respectively. Importantly, the expression levels of ICAM-1 determined by quantitative PET imaging showed a strong negative linear correlation with the growth of nonirradiated tumors. Moreover, genetic or pharmacologic up-regulation of ICAM-1 expression by either an intratumoral injection of engineered recombinant adenovirus or systemic administration of a Toll-like receptor 7 agonist-capsulated nanodrug could induce markedly increased abscopal responses to local RT in animal models. Mechanistic investigation revealed that ICAM-1 expression can enhance both the activation and tumor infiltration of CD8+ T cells to improve the responses of the nonirradiated tumors to RT. Together, our findings suggest that noninvasive PET imaging of ICAM-1 expression could be a powerful means to predict the responses of nonirradiated tumors to RT, which could facilitate the exploration of new combination RT strategies for effective ablation of primary and disseminated lesions.

Injectable Hydrogel as a Unique Platform for Antitumor Therapy Targeting Immunosuppressive Tumor Microenvironment.

Cancer immunotherapy can boost the immune response of patients to eliminate tumor cells and suppress tumor metastasis and recurrence. However, immunotherapy resistance and the occurrence of severe immune-related adverse effects are clinical challenges that remain to be addressed. The tumor microenvironment plays a crucial role in the therapeutic efficacy of cancer immunotherapy. Injectable hydrogels have emerged as powerful drug delivery platforms offering good biocompatibility and biodegradability, minimal invasion, convenient synthesis, versatility, high drug-loading capacity, controlled drug release, and low toxicity. In this review, we summarize the application of injectable hydrogels as a unique platform for targeting the immunosuppressive tumor microenvironment.

Anticancer Effect of Salvia plebeia and Its Active Compound by Improving T-Cell Activity via Blockade of PD-1/PD-L1 Interaction in Humanized PD-1 Mouse Model.

Immune checkpoint inhibitors, increasingly used to treat malignant tumors, are revolutionizing cancer treatment by improving the patient survival expectations. Despite the high antitumor efficacy of antibody therapeutics that bind to PD-1/PD-L1, study on small molecule-based PD-1/PD-L1 inhibitors is required to overcome the side effects of antibody therapeutics caused by their size and affinity. Herein, we investigated antitumor potential of Salvia plebeia R. Br. extract (SPE), which has been used as a traditional oriental medicine and food in many countries, and its components by the blockade of PD-1/PD-L1 interaction. SPE and its component cosmosiin effectively blocked the molecular interaction between PD-1 and PD-L1. SPE also inhibited tumor growth by increasing CD8+ T-cells in the tumor through the activation of tumor-specific T-cells in a humanized PD-1 mouse model bearing hPD-L1 knock-in MC38 colon adenocarcinoma tumor. This finding presents a preclinical strategy to develop small molecule-based anticancer drugs targeting the PD-1/PD-L1 immune checkpoint pathway.

Disturbed mitochondrial dynamics in CD8+ TILs reinforce T cell exhaustion.

The metabolic challenges present in tumors attenuate the metabolic fitness and antitumor activity of tumor-infiltrating T lymphocytes (TILs). However, it remains unclear whether persistent metabolic insufficiency can imprint permanent T cell dysfunction. We found that TILs accumulated depolarized mitochondria as a result of decreased mitophagy activity and displayed functional, transcriptomic and epigenetic characteristics of terminally exhausted T cells. Mechanistically, reduced mitochondrial fitness in TILs was induced by the coordination of T cell receptor stimulation, microenvironmental stressors and PD-1 signaling. Enforced accumulation of depolarized mitochondria with pharmacological inhibitors induced epigenetic reprogramming toward terminal exhaustion, indicating that mitochondrial deregulation caused T cell exhaustion. Furthermore, supplementation with nicotinamide riboside enhanced T cell mitochondrial fitness and improved responsiveness to anti-PD-1 treatment. Together, our results reveal insights into how mitochondrial dynamics and quality orchestrate T cell antitumor responses and commitment to the exhaustion program.

TILs and Anti-PD1 Therapy: An Alternative Combination Therapy for PDL1 Negative Metastatic Cervical Cancer.

BACKGROUND: We investigated the efficacy of TILs and anti-PD1 combination therapy in patients with metastatic cervical cancer with low MSI expression and PDL1-negative. METHODS: A total of 80 patients were put on TILs and anti-PD1 combination therapy, and the progression-free survival time (PFS) and overall survival time (OS) were assessed by Kaplan-Meier analysis. Univariate and multivariate analyses were performed to identify factors that could predict the prognosis of metastatic cervical cancer in the previously described patients. RESULTS: The objective response rate was 25%, whereas the mPFS and mOS were 6.1 and 11.3 months, respectively. The therapeutic efficacy was influenced by the characteristics of TILs, infection with HPV, and development of fever just after the therapy. CONCLUSION: Overall, our results show that the combination therapy of TILs and anti-PD1 significantly improves the prognosis of metastatic cervical cancer.

PGC-1α activator-induced fatty acid oxidation in tumor-infiltrating CTLs enhances effects of PD-1 blockade therapy in lung cancer.

PURPOSE: The present study aims to investigate the efficacy and mechanisms of peroxisome proliferator-activated receptor γ coactivator 1-α agonist, as adjuvant to programmed death-1 (PD-1) blockade in hyporesponsive lung cancer cells-derived in vivo tumor model, using bezafibrate. METHODS: Mouse Lewis lung carcinoma (LLC) xenograft models were established and treated with programmed death-ligand 1 (PD-L1) monoclonal antibodies with or without bezafibrate. Tumors or peripheral blood of mice were harvested to investigate the quality, quantity, and function as well as energetic metabolism of cytotoxic T lymphocytes (CTLs) by flow cytometry or quantitative real-time polymerase chain reaction. RESULTS: The combination of bezafibrate plus anti-PD-L1 reached synergistic tumoricidal effect in LLC xenograft mouse models, even though bezafibrate alone had no effect on tumor growth. Bezafibrate significantly facilitated CD8+ T cells infiltrating into tumor tissues by enhancing the expression of CXCL9 and CXCL10 within tumors as well as the receptor CXCR3 in infiltrating CTLs. Activated CTLs within tumors were also significantly upregulated by bezafibrate. Further data demonstrated that bezafibrate treatment could maintain the survival and functional capacity of tumor-infiltrating CTLs. Moreover, cellular reactive oxygen species in infiltrating CTLs and fatty acid oxidation (FAO)-related genes (PGC-1α, Cpt1a, and LCAD) expression within tumors were significantly increased after treatment with bezafibrate. CONCLUSIONS: Bezafibrate synergized the tumoricidal effect of PD-1 blockade in hyporesponsive lung cancer by expansion of effector CTLs within tumor microenvironment. The potential mechanism may relate to the capacity of bezafibrate in regulating FAO of tumor-infiltrating CTLs.

Effect of dietary omega-3 fatty acids on castrate-resistant prostate cancer and tumor-associated macrophages.

BACKGROUND: M2-like macrophages are associated with the pathogenesis of castrate-resistant prostate cancer (CRPC). We sought to determine if dietary omega-3 fatty acids (ω-3 FAs) delay the development and progression of CRPC and inhibit tumor-associated M2-like macrophages. METHODS: MycCap cells were grown subcutaneously in immunocompetent FVB mice. Mice were castrated when tumors reached 300 mm2. To study effects of dietary ω-3 FAs on development of CRPC, ω-3 or ω-6 diets were started 2 days after castration and mice sacrificed after early regrowth of tumors. To study ω-3 FA effects on progression of CRPC, tumors were allowed to regrow after castration before starting the diets. M2 (CD206+) macrophages were isolated from allografts to examine ω-3 FA effects on macrophage function. Omega-3 fatty acid effects on androgen-deprived RAW264.7 M2 macrophages were studied by RT-qPCR and a migration/ invasion assay. RESULTS: The ω-3 diet combined with castration lead to greater MycCap tumor regression (tumor volume reduction: 182.2 ± 33.6 mm3) than the ω-6 diet (tumor volume reduction: 148.3 ± 35.2; p = 0.003) and significantly delayed the time to CRPC (p = 0.006). Likewise, the ω-3 diet significantly delayed progression of established castrate-resistant MycCaP tumors (p = 0.003). The ω-3 diet (as compared to the ω-6 diet) significantly reduced tumor-associated M2-like macrophage expression of CSF-1R in the CRPC development model, and matrix metallopeptidase-9 (MMP-9) and vascular endothelial growth factor (VEGF) in the CRPC progression model. Migration of androgen-depleted RAW264.7 M2 macrophages towards MycCaP cells was reversed by addition of docosahexaenoic acid (ω-3). CONCLUSIONS: Dietary omega-3 FAs (as compared to omega-6 FAs) decreased the development and progression of CRPC in an immunocompetent mouse model, and had inhibitory effects on M2-like macrophage function. Clinical trials are warranted evaluating if a fish oil-based diet can delay the time to castration resistance in men on androgen deprivation therapy, whereas further preclinical studies are warranted evaluating fish oil for more advanced CRPC.

Synthesized natural peptides from amphibian skin secretions increase the efficacy of a therapeutic vaccine by recruiting more T cells to the tumour site.

BACKGROUND: Therapeutic vaccines against cervical cancer remain ineffective. Previously, we demonstrated that blocking the signalling of a cytokine, interleukin 10, at the time of immunisation elicited significantly higher numbers of antigen specific T cells and inhibited tumour growth in mice. RESULTS: In the current paper, we demonstrate, in a HPV16 E6/E7 transformed TC-1 tumour mouse model, that despite increased antigen specific T cell numbers, blocking IL-10 signalling at the time of immunisation does not increase the survival time of the TC-1 tumour bearing mice compared to mice receiving the same immunisation with no IL-10 signalling blockade. Moreover, the function of tumour infiltrating T cells isolated 3 weeks post TC-1 transplantation is more suppressed than those isolated 2 weeks after tumour inoculation. We demonstrate that synthesized caerin peptides, derived from amphibian skin secretions, 1) were able to inhibit TC-1 tumour growth both in vitro and in vivo; 2) are environmentally stable; and 3) promote the secretion of pro-inflammatory interlukine-6 by TC-1 cells. Notably caerin peptides were able to increase the survival time of TC-1 tumour bearing mice after therapeutic vaccination with a HPV16E7 peptide-based vaccine containing IL-10 inhibitor, via recruiting increased levels of T cells to the tumour site. CONCLUSION: Caerin peptides increase the efficacy of a therapeutic vaccine by recruiting more T cells to the tumour site.

Chromium 10× Single-Cell 3' mRNA Sequencing of Tumor-Infiltrating Lymphocytes.

Chromium 10× 3' V2 protocol is a 3' end counting single-cell mRNA sequencing protocol that allows to process and sequence RNA from thousands of cells in parallel. Chromium10× by 10× Genomics is an emulsion-based device that enables to compartmentalize single cells along with sets of uniquely barcoded primers and reverse transcription reagents into nanoscale droplets that are used as reaction chambers to generate barcoded full-length cDNA from single cells. After RT reaction single-stranded barcoded cDNAs are pooled together and processed to generate sequencing libraries compatible with the standard Illumina platforms. Here we show in detail the main steps of the protocol applied to the analysis of tumor-infiltrating T lymphocytes (TILs). The main steps are cell preparation, cDNA synthesis, library construction, and sequencing.This protocol refers specifically to the CG00052_SingleCell3_ReagentKitv2UserGuide_RevD downloadable from 10× Genomics website ( https://www.10xgenomics.com ) and does not substitute it. Always refer to this guide, paying attention to updates and revisions.

CD26/DPP4 - a potential biomarker and target for cancer therapy.

CD26/dipeptidyl peptidase (DPP)4 is a membrane-bound protein found in many cell types of the body, and a soluble form is present in body fluids. There is longstanding evidence that various primary tumors and also metastases express CD26/DPP4 to a variable extent. By cleaving dipeptides from peptides with a proline or alanine in the penultimate position at the N-terminus, it regulates the activity of incretin hormones, chemokines and many other peptides. Due to these effects and interactions with other molecules, a tumor promoting or suppressing role can be attributed to CD26/DPP4. In this review, we discuss the existing evidence on the expression of soluble or membrane-bound CD26/DPP4 in malignant diseases, along with the most recent findings on CD26/DPP4 as a therapeutic target in specific malignancies. The expression and possible involvement of the related DPP8 and DPP9 in cancer are also reviewed. A higher expression of CD26/DPP4 is found in a wide variety of tumor entities, however more research on CD26/DPP4 in the tumor microenvironment is needed to fully explore its use as a tumor biomarker. Circulating soluble CD26/DPP4 has also been studied as a cancer biomarker, however, the observed decrease in most cancer patients does not seem to be cancer specific. Encouraging results from experimental work and a recently reported first phase clinical trial targeting CD26/DPP4 in mesothelioma, renal and urological tumors pave the way for follow-up clinical studies, also in other tumor entities, possibly leading to the development of more effective complementary therapies against cancer.

A potential role for peripheral natural killer cell activity induced by preoperative chemotherapy in breast cancer patients.

Tumor-infiltrating lymphocytes are an important prognostic factor after neoadjuvant chemotherapy (NAC) in patients with breast cancer. Natural killer (NK) cells play critical roles in antitumor immune surveillance. Here, we assessed the relationship between peripheral natural killer (pNK) cell activity, tumor microenvironmental factors (TMEFs), and the therapeutic efficacy of preoperative chemotherapy in patients with breast cancer. In a cohort of 39 patients diagnosed with stage II-IV breast cancer who received NAC, we measured pNK cell activity by chromium release assay and assessed TMEF levels by next-generation sequencing. Following NAC, pNK cell activity was increased in 24/39 patients but decreased in 15/39 patients. Increased pNK cell activity following preoperative chemotherapy was associated significantly with the disappearance of axillary lymph node metastasis (Ax+; p = 0.0235). Increased pNK cell activity remained significantly associated with the disappearance of Ax+ in multivariate logistic regression analysis (OR 5.41, 95% CI 1.19-24.52, p = 0.0283). A Grade 2 or higher effect of NAC was associated with high pre-NAC cytotoxic T lymphocyte-associated protein 4 (CTLA-4) levels (p = 0.0281) and elevated post-NAC NK (p = 0.0005) cells and transforming growth factor-beta (TGF-ß; p = 0.0350) levels. The disappearance of Ax+ was associated with high pre-NAC CTLA-4 levels (p = 0.0278) and elevated CD4 levels after NAC (p = 0.0250). The systemic activation of pNK cells after NAC may improve metastatic tumor elimination in patients with breast cancer owing to a release from local immunosuppression, and immune activation in the tumor microenvironment.

Integrative analysis reveals distinct subtypes with therapeutic implications in KRAS-mutant lung adenocarcinoma.

BACKGROUND: KRAS-mutant lung adenocarcinomas (LUADs) are heterogeneous and frequently occur in smokers. The heterogeneity of KRAS-mutant LUAD has been an obstacle for the drug discovery. METHODS: We integrated multiplatform datatypes and identified two corresponding subtypes in the patients and cell lines. We further characterized the features of these two subtypes and performed drug screening to identify subtype-specific drugs. Finally, we used the defining features of the KRAS subtypes for drug sensitivity prediction. FINDINGS: Patient-Subtype 1 (PS1) was characterized by increased smoking-related mutational signature activity, a low tumor-infiltrating lymphocyte (TIL)-associating score and STK11/KEAP1 co-mutations. Patient-Subtype 2 (PS2) was characterized by an increased smoking-related methylation signature activity, a high TIL-associating score and increased KRAS dependency. The cell line subtypes faithfully recapitulated all the patients' features. Drug screening of the two cell line subtypes yielded several potential candidates, such as cytarabine and enzastaurin for Cell-line-Subtype 1 (CS1) and a BTK inhibitor QL-XII-61 for Cell-line-Subtype 2 (CS2). The defining features, such as smoking-related methylation signature, were significantly associated with the sensitivity to several drugs. INTERPRETATION: The heterogeneity of KRAS-mutant LUAD is associated with smoking-related genomic and epigenomic aberration along with other features such as immunogenicity, KRAS dependency and STK11/KEAP1 co-mutations. These features might be used as biomarkers for drug sensitivity prediction. FUND: This research was funded by the Young Scientists Fund of the National Natural Science Foundation of China, the Natural Science Foundation of Fujian Province, China and the Education and Research Foundation for Young Scholars of Education Department of Fujian Province, China.

Radiation and Local Anti-CD40 Generate an Effective in situ Vaccine in Preclinical Models of Pancreatic Cancer.

Radiation therapy induces immunogenic cell death, which can theoretically stimulate T cell priming and induction of tumor-specific memory T cell responses, serving as an in situ vaccine. In practice, this abscopal effect is rarely observed. We use two mouse models of pancreatic cancer to show that a single dose of stereotactic body radiation therapy (SBRT) synergizes with intratumoral injection of agonistic anti-CD40, resulting in regression of non-treated contralateral tumors and formation of long-term immunologic memory. Long-term survival was not observed when mice received multiple fractions of SBRT, or when TGFß blockade was combined with SBRT. SBRT and anti-CD40 was so effective at augmenting T cell priming, that memory CD8 T cell responses to both tumor and self-antigens were induced, resulting in vitiligo in long-term survivors.

Local Phototherapy Synergizes with Immunoadjuvant for Treatment of Pancreatic Cancer through Induced Immunogenic Tumor Vaccine.

Purpose: To develop a synergistic combination therapy for advanced pancreatic cancer, using local phototherapy and immunotherapy, and to determine the efficacy and mechanism of the novel combination therapy using a highly metastatic pancreatic tumor model in mice.Experimental Design: Mice bearing Panc02-H7 pancreatic tumors (both subcutaneous and orthotopic) were treated with noninvasive or interventional photothermal therapy, followed by local application of an immunoadjuvant. Tumor growth and animal survival were assessed. Immune cell populations within spleen and tumors were evaluated by FACS and IHC, and cytokine levels were determined by ELISA.Results: Up to 75% of mice bearing subcutaneous tumors treated with combination therapy had complete tumor regression. Local photothermal therapy exposed/released damage-associated molecular patterns, which initiated an immunogenic tumor cell death, resulting in infiltration of antigen-presenting cells and Th1 immunity. Concomitant application of immunoadjuvant amplified Th1 immunity, especially the tumor-specific cytotoxic T lymphocyte response, with increased quantity and quality of T cells. Combination therapy also induced tumor-specific immune memory, as demonstrated by resistance to tumor rechallenge and production of memory T cells. For the treatment of orthotopic tumor, the combination therapy significantly reduced the primary tumors and metastases, and prolonged the animal survival time.Conclusions: This study indicated that combination of local phototherapy and immunotherapy induced a systemic immunity against established tumors and metastases in an aggressive, preclinical pancreatic tumor model, leading to a potential clinical method for patients with advanced pancreatic cancer. Clin Cancer Res; 24(21); 5335-46. ©2018 AACR.

CD8+ T-Cell Density Imaging with 64Cu-Labeled Cys-Diabody Informs Immunotherapy Protocols.

Purpose: Noninvasive and quantitative tracking of CD8+ T cells by PET has emerged as a potential technique to gauge response to immunotherapy. We apply an anti-CD8 cys-diabody, labeled with 64Cu, to assess the sensitivity of PET imaging of normal and diseased tissue.Experimental Design: Radiolabeling of an anti-CD8 cys-diabody (169cDb) with 64Cu was developed. The accumulation of 64Cu-169cDb was evaluated with PET/CT imaging (0, 5, and 24 hours) and biodistribution (24 hours) in wild-type mouse strains (n = 8/group studied with imaging and IHC or flow cytometry) after intravenous administration. Tumor-infiltrating CD8+ T cells in tumor-bearing mice treated with CpG and αPD-1 were quantified and mapped (n = 6-8/group studied with imaging and IHC or flow cytometry).Results: We demonstrate the ability of immunoPET to detect small differences in CD8+ T-cell distribution between mouse strains and across lymphoid tissues, including the intestinal tract of normal mice. In FVB mice bearing a syngeneic HER2-driven model of mammary adenocarcinoma (NDL), 64Cu-169cDb PET imaging accurately visualized and quantified changes in tumor-infiltrating CD8+ T cells in response to immunotherapy. A reduction in the circulation time of the imaging probe followed the development of treatment-related liver and splenic hypertrophy and provided an indication of off-target effects associated with immunotherapy protocols.Conclusions: 64Cu-169cDb imaging can spatially map the distribution of CD8+ T cells in normal organs and tumors. ImmunoPET imaging of tumor-infiltrating cytotoxic CD8+ T cells detected changes in T-cell density resulting from adjuvant and checkpoint immunotherapy protocols in our preclinical evaluation. Clin Cancer Res; 24(20); 4976-87. ©2018 AACR.

Polysaccharides from Chinese Herbal Lycium barbarum Induced Systemic and Local Immune Responses in H22 Tumor-Bearing Mice.

Lycium barbarum polysaccharide (LBP) is isolated from the fruit of Chinese herbal Lycium barbarum. Previous studies had demonstrated that LBP could inhibit tumor growth and enhance the immunity in mice. However, the effect of LBP on systemic and local immune responses in vivo, especially on phenotypic and functional changes of T cells, is still largely unknown. In the present study, we investigated the effects of LBP on systemic and local T cell-dependent antitumor immune responses in H22 tumor-bearing mice. The results showed that LBP could inhibit the solid tumor growth in mice, but showed little effect on the body weight or spleen index. Furthermore, LBP could maintain high levels of T cells in peripheral blood (PB), tumor draining lymph node (TDLN), and tumor tissue, prevent the increase of Tregs while promote infiltration of CD8+ T cells in tumor tissue, inhibit the production of TGF-ß1 and IL-10 in serum, decrease the exhaustion phenotype of T cells, and maintain cytotoxicity of lymphocytes. Taken together, our results demonstrated that LBP simultaneously induced systemic and local immune responses in H22 tumor-bearing mice by alleviating immunosuppression and maintaining antitumor immune responses in mice.

Exosomes from heat-stressed tumour cells inhibit tumour growth by converting regulatory T cells to Th17 cells via IL-6.

Exosomes derived from heat-stressed tumour cells (HS-TEXs), which contain abundant heat shock protein (HSP) 70, strongly induce antitumour immune responses. HSP70-induced interleukin (IL)-6 promotes IL-17 expression and causes rejection of established prostate tumours. However, it remains unclear whether HS-TEXs exhibit antitumour effects by converting regulatory T cells (Tregs ) into T helper type 17 (Th17) cells. In this study, we found that compared with TEXs, HS-TEXs were more potent in stimulating secretion of IL-6 from dendritic cells. In vitro, IL-6 blocked tumour cell-derived transforming growth factor beta 1-induced Treg differentiation and promoted Th17 cell differentiation. HS-TEXs exerted strong antitumour effects, converting Tregs into Th17 cells with high efficiency, a process that was entirely dependent upon IL-6. Neutralization of IL-17 completely abolished the antitumour effect of TEXs, but only partially inhibited that of HS-TEXs. In addition, we found higher levels of IL-6 and IL-17 in serum from tumour patients treated with hyperthermia, and an increase in Th17 cells and a decrease in Tregs was detected in peripheral blood mononuclear cells isolated from these patients after hyperthermia. Therefore, our results demonstrate that HS-TEXs possess a powerful capacity to convert immunosuppressive Tregs into Th17 cells via IL-6, which contributes to their potent antitumour effect.