Efficacy and safety of BVAC-C in HPV type 16- or 18-positive cervical carcinoma who failed 1st platinum-based chemotherapy: a phase I/IIa study.

Background: BVAC-C, a B cell- and monocyte-based immunotherapeutic vaccine transfected with recombinant HPV E6/E7, was well tolerated in HPV-positive recurrent cervical carcinoma patients in a phase I study. This phase IIa study investigates the antitumor activity of BVAC-C in patients with HPV 16- or 18-positive cervical cancer who had experienced recurrence after a platinum-based combination chemotherapy. Patients and methods: Patients were allocated to 3 arms; Arm 1, BVAC-C injection at 0, 4, 8 weeks; Arm 2, BVAC-C injection at 0, 4, 8, 12 weeks; Arm 3, BVAC-C injection at 0, 4, 8, 12 weeks with topotecan at 2, 6, 10, 14 weeks. Primary endpoints were safety and objective response rate (ORR) as assessed by an independent radiologist according to Response Evaluation Criteria in Solid Tumors version 1.1. Secondary endpoints included the disease control rate (DCR), duration of response (DOR), progression-free survival (PFS), and overall survival (OS). Results: Of the 30 patients available for analysis, the ORR was 19.2% (Arm 1: 20.0% (3/15), Arm 2: 33.3% (2/6), Arm3: 0%) and the DCR was 53.8% (Arm 1: 57.1%, Arm 2: 28.6%, Arm3: 14.3%). The median DOR was 7.5 months (95% CI 7.1-not reported), the median PFS was 5.8 months (95% CI 4.2-10.3), and the median OS was 17.7 months (95% CI 12.0-not reported). All evaluated patients showed not only inflammatory cytokine responses (IFN-γ or TNF-α) but also potent E6/E7-specific T cell responses upon vaccinations. Immune responses of patients after vaccination were correlated with their clinical responses. Conclusion: BVAC-C represents a promising treatment option and a manageable safety profile in the second-line setting for this patient population. Further studies are needed to identify potential biomarkers of response. Clinical trial registration: ClinicalTrials.gov, identifier NCT02866006.

Inhibition of topoisomerase I shapes antitumor immunity through the induction of monocyte-derived dendritic cells.

Understanding the rationale of combining immunotherapy and other anticancer treatment modalities is of great interest because of interpatient variability in single-agent immunotherapy. Here, we demonstrated that topoisomerase I inhibitors, a class of chemotherapeutic drugs, can alter the tumor immune landscape, corroborating their antitumor effects combined with immunotherapy. We observed that topotecan-conditioned TC-1 tumors were occupied by a vast number of monocytic cells that highly express CD11c, CD64, and costimulatory molecules responsible for the favorable changes in the tumor microenvironment. Ly6C+MHC-II+CD11chiCD64hi cells, referred to as topotecan-induced monocyte-derived dendritic cells (moDCs), proliferate and activate antigen-specific CD8+ T cells to levels equivalent to those of conventional DCs. Phenotypic changes in Ly6C+ cells towards moDCs were similarly induced by exposure to topotecan in vitro, which was more profoundly facilitated in the presence of tumor cells. Notably, anti-M-CSFR reversed the acquisition of DC-like properties of topotecan-induced moDCs, leading to the abolition of the antitumor effect of topotecan combined with a cancer vaccine. In short, topoisomerase I inhibitors generate monocyte-derived antigen-presenting cells in tumors, which could be mediated by M-CSF-M-CSFR signaling.

Enhanced Immunogenicity of Engineered HER2 Antigens Potentiates Antitumor Immune Responses.

For cancer vaccines, the selection of optimal tumor-associated antigens (TAAs) that can maximize the immunogenicity of the vaccine without causing unwanted adverse effects is challenging. In this study, we developed two engineered Human epidermal growth factor receptor 2 (HER2) antigens, K965 and K1117, and compared their immunogenicity to a previously reported truncated HER2 antigen, K684, within a B cell and monocyte-based vaccine (BVAC). We found that BVAC-K965 and BVAC-K1117 induced comparable antigen-specific antibody responses and antigen-specific T cell responses to BVAC-K684. Interestingly, BVAC-K1117 induced more potent antitumor activity than the other vaccines in murine CT26-HER2 tumor models. In addition, BVAC-K1117 showed enhanced antitumor effects against truncated p95HER2-expressing CT26 tumors compared to BVAC-K965 and BVAC-K684 based on the survival analysis by inducing T cell responses against intracellular domain (ICD) epitopes. The increased ICD epitope-specific T cell responses induced by BVAC-K1117 compared to BVAC-K965 and BVAC-K684 were recapitulated in human leukocyte antigen (HLA)-untyped human PBMCs and HLA-A*0201 PBMCs. Furthermore, we also observed synergistic antitumor effects between BVAC-K1117 and anti-PD-L1 antibody treatment against CT26-HER2 tumors. Collectively, our findings demonstrate that inclusion of a sufficient number of ICD epitopes of HER2 in cellular vaccines can improve the antitumor activity of the vaccine and provide a way to optimize the efficacy of anticancer cellular vaccines targeting HER2.

GITR Agonism Triggers Antitumor Immune Responses through IL21-Expressing Follicular Helper T Cells.

Although treatment with the glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR) agonistic antibody (DTA-1) has shown antitumor activity in various tumor models, the underlying mechanism is not fully understood. Here, we demonstrate that interleukin (IL)-21-producing follicular helper T (Tfh) cells play a crucial role in DTA-1-induced tumor inhibition. The administration of DTA-1 increased IL21 expression by Tfh cells in an antigen-specific manner, and this activation led to enhanced antitumor cytotoxic T lymphocyte (CTL) activity. Mice treated with an antibody that neutralizes the IL21 receptor exhibited decreased antitumor activity when treated with DTA-1. Tumor growth inhibition by DTA-1 was abrogated in Bcl6 fl/fl Cd4 Cre mice, which are genetically deficient in Tfh cells. IL4 was required for optimal induction of IL21-expressing Tfh cells by GITR costimulation, and c-Maf mediated this pathway. Thus, our findings identify GITR costimulation as an inducer of IL21-expressing Tfh cells and provide a mechanism for the antitumor activity of GITR agonism.

Differentiation of c-Kit+ CD24+ natural killer cells into myeloid cells in a GATA-2-dependent manner.

Myeloid progenitor cells have generally been considered the predominant source of myeloid cells under steady-state conditions. Here we show that NK cells contributed to a myeloid cell lineage pool in naïve and tumor-bearing mice. Using fate tracing of NKp46+ cells, we found that myeloid cells could be derived from NK cells. Notably, among mature CD11b+ CD27+ NK cells, c-Kit+ CD24+ NK cells were capable of differentiating into a range of myeloid lineages in vitro and produced neutrophils and monocytes in vivo. The differentiation was completely inhibited by NK-stimulating cytokines. In addition to the potential for differentiation into myeloid cells, c-Kit+ CD24+ NK cells retained NK cell phenotypes and effector functions. Mechanistically, GATA-2 was necessary for the differentiation of c-Kit+ CD24+ NK cells. Therefore, we discovered that GATA-2-dependent differentiation of c-Kit+ CD24+ NK cells contributes to myeloid cell development and identified a novel pathway for myeloid lineage commitment under physiological conditions.

Roles of NKT cells in cancer immunotherapy.

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.

GM-CSF Promotes Antitumor Immunity by Inducing Th9 Cell Responses.

GM-CSF as an adjuvant has been shown to promote antitumor immunity in mice and humans; however, the underlying mechanism of GM-CSF-induced antitumor immunity remains incompletely understood. In this study, we demonstrate that GM-CSF potentiates the efficacy of cancer vaccines through IL9-producing Th (Th9) cells. GM-CSF selectively enhanced Th9 cell differentiation by regulating the COX2-PGE2 pathway while inhibiting the differentiation of induced regulatory T (iTreg) cells in vitro and in vivo GM-CSF-activated monocyte-derived dendritic cells converted tumor-specific naïve Th cells into Th9 cells, and delayed tumor growth by inducing antitumor CTLs in an IL9-dependent manner. Our findings reveal a mechanism for the adjuvanticity of GM-CSF and provide a rationale for the use of GM-CSF in cancer vaccines.

Hydrogel bowls for cleaning oil spills on water.

We demonstrate a hydrogel bowl capable of selectively and rapidly collecting spilled oil while floating on water. The bowl has macroscopic openings in its sidewall, and its surface is first coated with octadecyltrichlorosilane (OTS) and then with diffusion pump oil, which imparts exceptional hydrophobic, oleophilic, and high oil wettability properties. The use of a hydrogel makes it possible to obtain surface hydrophobicity and oleophilicity, while also being inexpensive, eco-friendly, and easy to fabricate. Using a prototype of the bowl and a small pump system, we demonstrate that oils with a broad range of viscosities (2.7-2000.0 cSt at 20-40 °C) are more rapidly and efficiently collected from the surface of both pure water and seawater than with any other reported technique. The hydrogel bowl can collect oil for more than one month without losing its efficiency and can be stored in oil for reuse. Therefore, such hydrogel bowls represent a new alternative to conventional oil spill remediation techniques.

Activation of NKT Cells in an Anti-PD-1-Resistant Tumor Model Enhances Antitumor Immunity by Reinvigorating Exhausted CD8 T Cells.

PD-1-based cancer immunotherapy is a successful example of immune checkpoint blockade that provides long-term durable therapeutic effects in patients with cancer across a wide spectrum of cancer types. Accumulating evidence suggests that anti-PD-1 therapy enhances antitumor immunity by reversing the function of exhausted T cells in the tumor environment. However, the responsiveness rate of patients with cancer to anti-PD-1 therapy remains low, providing an urgent need for optimization and improvement. In this study, we designed an anti-PD-1-resistant mouse tumor model and showed that unresponsiveness to anti-PD-1 is associated with a gradual increase in CD8 T-cell exhaustion. We also found that invariant natural killer T cell stimulation by the synthetic ligand α-galactosylceramide (αGC) can enhance the antitumor effect in anti-PD-1-resistant tumors by restoring the effector function of tumor antigen-specific exhausted CD8 T cells. IL2 and IL12 were among the cytokines produced by αGC stimulation critical for reinvigorating exhausted CD8 T cells in tumor-bearing mice and patients with cancer. Furthermore, we observed a synergistic increase in the antitumor effect between αGC-loaded antigen-presenting cells and PD-1 blockade in a therapeutic murine tumor model. Our study suggests NKT cell stimulation as a promising therapeutic strategy for the treatment of patients with anti-PD-1-resistant cancer.Significance: These findings provide mechanistic insights into the application of NKT cell stimulation as a potent adjuvant for immunotherapy against advanced cancer. Cancer Res; 78(18); 5315-26. ©2018 AACR.

IL-21-mediated reversal of NK cell exhaustion facilitates anti-tumour immunity in MHC class I-deficient tumours.

During cancer immunoediting, loss of major histocompatibility complex class I (MHC-I) in neoplasm contributes to the evasion of tumours from host immune system. Recent studies have demonstrated that most natural killer (NK) cells that are found in advanced cancers are defective, releasing the malignant MHC-I-deficient tumours from NK-cell-dependent immune control. Here, we show that a natural killer T (NKT)-cell-ligand-loaded tumour-antigen expressing antigen-presenting cell (APC)-based vaccine effectively eradicates these advanced tumours. During this process, we find that the co-expression of Tim-3 and PD-1 marks functionally exhausted NK cells in advanced tumours and that MHC-I downregulation in tumours is closely associated with the induction of NK-cell exhaustion in both tumour-bearing mice and cancer patients. Furthermore, the recovery of NK-cell function by IL-21 is critical for the anti-tumour effects of the vaccine against advanced tumours. These results reveal the process involved in the induction of NK-cell dysfunction in advanced cancers and provide a guidance for the development of strategies for cancer immunotherapy.

Tumor-derived osteopontin suppresses antitumor immunity by promoting extramedullary myelopoiesis.

Extramedullary myelopoiesis occurs commonly in tumor-bearing animals and is known to lead to accumulation of peripheral myeloid-derived suppressor cells (MDSC), which play an important role in immune escape. However, the cellular and molecular mechanisms by which tumors induce extramedullary myelopoiesis are poorly understood. In this study, we found that osteopontin expressed by tumor cells enhances extramedullary myelopoiesis in a CD44-dependent manner through the Erk1/2-MAPK pathway. Osteopontin-mediated extramedullary myelopoiesis was directly associated with increased MDSCs in tumor-bearing hosts. More importantly, osteopontin silencing in tumor cells delayed both tumor growth and extramedullary myelopoiesis, while the same treatment did not affect tumor growth in vitro. Finally, treatment with an antibody against osteopontin inhibited tumor growth and synergized with cell-based immunotherapeutic vaccines in mediating antitumor immunity. Our findings unveil a novel immunosuppressive role for tumor-derived osteopontin and offer a rationale for its therapeutic targeting in cancer treatment.

A mirror for lab-based quasi-monochromatic parallel x-rays.

A multilayered parabolic mirror with six W/Al bilayers was designed and fabricated to generate monochromatic parallel x-rays using a lab-based x-ray source. Using this mirror, curved bright bands were obtained in x-ray images as reflected x-rays. The parallelism of the reflected x-rays was investigated using the shape of the bands. The intensity and monochromatic characteristics of the reflected x-rays were evaluated through measurements of the x-ray spectra in the band. High intensity, nearly monochromatic, and parallel x-rays, which can be used for high resolution x-ray microscopes and local radiation therapy systems, were obtained.

Serum amyloid A3 exacerbates cancer by enhancing the suppressive capacity of myeloid-derived suppressor cells via TLR2-dependent STAT3 activation.

Myeloid-derived suppressor cells (MDSCs), which suppress diverse innate and adaptive immune responses and thereby provide an evasion mechanism for tumors, are emerging as a key population linking inflammation to cancer. Although many inflammatory factors that induce MDSCs in the tumor microenvironment are known, the crucial components and the underlying mechanisms remain elusive. In this study, we proposed a novel mechanism by which serum amyloid A3 (SAA3), a well-known inflammatory factor, connects MDSCs with cancer progression. We found that SAA3 expression in BALB/c mice increased in monocytic MDSCs (Mo MDSCs) with tumor growth. The induction of SAA3 by apo-SAA treatment in Mo MDSCs enhanced their survival and suppressive activity, while it inhibited GM-CSF-induced differentiation. Endogenous SAA3 itself contributed to the increase in the survival and suppressive activity of Mo MDSCs. We demonstrated that SAA3 induced TLR2 signaling, in turn increasing the autocrine secretion of TNF-α, that led to STAT3 activation. In addition, activated STAT3 enhanced the suppressive activity of Mo MDSCs. Furthermore, SAA3 induction in Mo MDSCs contributed to accelerating tumor progression in vivo. Collectively, these data suggest a novel mechanism by which Mo MDSCs mediate inflammation through SAA3-TLR2 signaling and thus exacerbate cancer progression by a STAT3-dependent mechanism.