Arginase-1 inhibition reduces migration ability and metastatic colonization of colon cancer cells.

BACKGROUND: Arginase-1 (ARG1), a urea cycle-related enzyme, catalyzes the hydrolysis of arginine to urea and ornithine, which regulates the proliferation, differentiation, and function of various cells. However, it is unclear whether ARG1 controls the progression and malignant alterations of colon cancer. METHODS: We established metastatic colonization mouse model and ARG1 overexpressing murine colon cancer CT26 cells to investigate whether activation of ARG1 was related to malignancy of colon cancer cells in vivo. Living cell numbers and migration ability of CT26 cells were evaluated in the presence of ARG inhibitor in vitro. RESULTS: Inhibition of arginase activity significantly suppressed the proliferation and migration ability of CT26 murine colon cancer cells in vitro. Overexpression of ARG1 in CT26 cells reduced intracellular L-arginine levels, enhanced cell migration, and promoted epithelial-mesenchymal transition. Metastatic colonization of CT26 cells in lung and liver tissues was significantly augmented by ARG1 overexpression in vivo. ARG1 gene expression was higher in the tumor tissues of liver metastasis than those of primary tumor, and arginase inhibition suppressed the migration ability of HCT116 human colon cancer cells. CONCLUSION: Activation of ARG1 is related to the migration ability and metastatic colonization of colon cancer cells, and blockade of this process may be a novel strategy for controlling cancer malignancy.

IFN-α/ß-mediated NK2R expression is related to the malignancy of colon cancer cells.

Neurokinin 2 receptor (NK2R), a G protein-coupled receptor for neurokinin A (NKA), a tachykinin family member, regulates various physiological functions including pain response, relaxation of smooth muscle, dilation of blood vessels, and vascular permeability. However, the precise role and regulation of NK2R expression in cancer cells have not been fully elucidated. In this study, we found that high NK2R gene expression was correlated with the poor survival of colorectal cancer patients, and Interferon (IFN-α/ß) stimulation significantly enhanced NK2R gene expression level of colon cancer cells in a Janus kinas 1/2 (JAK 1/2)-dependent manner. NKA stimulation augmented viability/proliferation and phosphorylation of Extracellular-signal-regulated kinase 1/2 (ERK1/2) levels of IFN-α/ß-treated colon cancer cells and NK2R blockade by using a selective antagonist reduced the proliferation in vitro. Administration of an NK2R antagonist alone or combined with polyinosinic-polycytidylic acid, a synthetic analog of double-stranded RNA, to CT26-bearing mice significantly suppressed tumorigenesis. NK2R-overexpressing CT26 cells showed enhanced tumorigenesis and metastatic colonization in both lung and liver after the inoculation into mice. These findings indicate that IFN-α/ß-mediated NK2R expression is related to the malignancy of colon cancer cells, suggesting that NK2R blockade may be a promising strategy for colon cancers.

Personalized immunotherapy in cancer precision medicine.

With the significant advances in cancer genomics using next-generation sequencing technologies, genomic and molecular profiling-based precision medicine is used as a part of routine clinical test for guiding and selecting the most appropriate treatments for individual cancer patients. Although many molecular-targeted therapies for a number of actionable genomic alterations have been developed, the clinical application of such information is still limited to a small proportion of cancer patients. In this review, we summarize the current status of personalized drug selection based on genomic and molecular profiling and highlight the challenges how we can further utilize the individual genomic information. Cancer immunotherapies, including immune checkpoint inhibitors, would be one of the potential approaches to apply the results of genomic sequencing most effectively. Highly cancer-specific antigens derived from somatic mutations, the so-called neoantigens, occurring in individual cancers have been in focus recently. Cancer immunotherapies, which target neoantigens, could lead to a precise treatment for cancer patients, despite the challenge in accurately predicting neoantigens that can induce cytotoxic T cells in individual patients. Precise prediction of neoantigens should accelerate the development of personalized immunotherapy including cancer vaccines and T-cell receptor-engineered T-cell therapy for a broader range of cancer patients.

Immunogenomics in personalized cancer treatments.

Recent advances in next-generation sequencing technologies have led to significant improvements in cancer genomic research and cancer treatment. Through the use of comprehensive cancer genome data, precision medicine has become more of a reality; albeit, at present, only ~10-15% of patients can benefit from current genomic testing practices. Improvements in cancer genome analyses have contributed to a better understanding of antitumor immunity and have provided solutions for targeting highly cancer-specific neoantigens generated from somatic mutations in individual patients. Since then, numerous studies have demonstrated the importance of neoantigens and neoantigen-reactive T cells in the tumor microenvironment and how their presence influences the beneficial responses associated with various cancer immunotherapies, including immune checkpoint inhibitor therapy. Indeed, cancer immunotherapies that explicitly target neoantigens specific to individual cancer patients would lead to the ultimate form of cancer precision medicine. For this to be realized, several issues would need to be overcome, including the accurate prediction and selection of neoantigens that can induce cytotoxic T cells in individual patients. The precise prediction of target neoantigens will likely accelerate the development of personalized immunotherapy including cancer vaccines and T-cell receptor-engineered T-cell therapy for patients with cancer.

SARS-CoV-2 genomic variations associated with mortality rate of COVID-19.

The coronavirus disease 2019 (COVID-19) outbreak, caused by SARS-CoV-2, has rapidly expanded to a global pandemic. However, numbers of infected cases, deaths, and mortality rates related to COVID-19 vary from country to country. Although many studies were conducted, the reasons of these differences have not been clarified. In this study, we comprehensively investigated 12,343 SARS-CoV-2 genome sequences isolated from patients/individuals in six geographic areas and identified a total of 1234 mutations by comparing with the reference SARS-CoV-2 sequence. Through a hierarchical clustering based on the mutant frequencies, we classified the 28 countries into three clusters showing different fatality rates of COVID-19. In correlation analyses, we identified that ORF1ab 4715L and S protein 614G variants, which are in a strong linkage disequilibrium, showed significant positive correlations with fatality rates (r = 0.41, P = 0.029 and r = 0.43, P = 0.022, respectively). We found that BCG-vaccination status significantly associated with the fatality rates as well as number of infected cases. In BCG-vaccinated countries, the frequency of the S 614G variant had a trend of association with the higher fatality rate. We also found that the frequency of several HLA alleles, including HLA-A*11:01, were significantly associated with the fatality rates, although these factors were associated with number of infected cases and not an independent factor to affect fatality rate in each country. Our findings suggest that SARS-CoV-2 mutations as well as BCG-vaccination status and a host genetic factor, HLA genotypes might affect the susceptibility to SARS-CoV-2 infection or severity of COVID-19.

Bioinformatic prediction of potential T cell epitopes for SARS-Cov-2.

To control and prevent the current COVID-19 pandemic, the development of novel vaccines is an emergent issue. In addition, we need to develop tools that can measure/monitor T-cell and B-cell responses to know how our immune system is responding to this deleterious virus. However, little information is currently available about the immune target epitopes of novel coronavirus (SARS-CoV-2) to induce host immune responses. Through a comprehensive bioinformatic screening of potential epitopes derived from the SARS-CoV-2 sequences for HLAs commonly present in the Japanese population, we identified 2013 and 1399 possible peptide epitopes that are likely to have the high affinity (<0.5%- and 2%-rank, respectively) to HLA class I and II molecules, respectively, that may induce CD8+ and CD4+ T-cell responses. These epitopes distributed across the structural (spike, envelope, membrane, and nucleocapsid proteins) and the nonstructural proteins (proteins corresponding to six open reading frames); however, we found several regions where high-affinity epitopes were significantly enriched. By comparing the sequences of these predicted T cell epitopes to the other coronaviruses, we identified 781 HLA-class I and 418 HLA-class II epitopes that have high homologies to SARS-CoV. To further select commonly-available epitopes that would be applicable to larger populations, we calculated population coverages based on the allele frequencies of HLA molecules, and found 2 HLA-class I epitopes covering 83.8% of the Japanese population. The findings in the current study provide us valuable information to design widely-available vaccine epitopes against SARS-CoV-2 and also provide the useful information for monitoring T-cell responses.

IL6 Modulates the Immune Status of the Tumor Microenvironment to Facilitate Metastatic Colonization of Colorectal Cancer Cells.

It is unknown as to how liver metastases are correlated with host immune status in colorectal cancer. In this study, we found that IL6, a proinflammatory cytokine produced in tumor-bearing states, promoted the metastatic colonization of colon cancer cells in association with dysfunctional antitumor immunity. In IL6-deficient mice, metastatic colonization of CT26 cells in the liver was reduced, and the antitumor effector function of CD8+ T cells, as well as IL12 production by CD11c+ dendritic cells, were augmented in vivo IL6-deficient mice exhibited enhanced IFN-AR1-mediated type I interferon signaling, which upregulated PD-L1 and MHC class I expression on CT26 cells. In vivo injection of anti-PD-L1 effectively suppressed the metastatic colonization of CT26 cells in Il6 -/- but not in Il6 +/+ mice. Finally, we confirmed that colorectal cancer patients with low IL6 expression in their primary tumors showed prolonged disease-free survival. These findings suggest that IL6 may be a promising target for the treatment of metastasis in colorectal cancers by improving host immunity.

[Clinical Features in Surgical Cases of Female Spontaneous Pneumothorax;Comparison with Male Patients].

We assessed the clinical features in surgery cases of female spontaneous pneumothorax by comparing them with male patients. One hundred six patients ( female/male:16/90)who had undergone surgery for spontaneous pneumothorax between January 2003 and August 2013 was retrospectively studied. Patient background, pneumothorax classification and treatment were assessed. No significant difference was found in patient background and treatment. In pneumothorax classification, the frequency of secondary pneumothorax in females was significantly greater than that in males (p<0.001). Additionally, in females, the number of bulla identified during surgery was significantly fewer and the number of recurrences before surgery was more frequent than that in males.

Lack of interleukin-6 in the tumor microenvironment augments type-1 immunity and increases the efficacy of cancer immunotherapy.

Conquering immunosuppression in tumor microenvironments is crucial for effective cancer immunotherapy. It is well known that interleukin (IL)-6, a pleiotropic cytokine, is produced in the tumor-bearing state. In the present study, we investigated the precise effects of IL-6 on antitumor immunity and the subsequent tumorigenesis in tumor-bearing hosts. CT26 cells, a murine colon cancer cell line, were intradermally injected into wild-type and IL-6-deficient mice. As a result, we found that tumor growth was decreased significantly in IL-6-deficient mice compared with wild-type mice and the reduction was abrogated by depletion of CD8+ T cells. We further evaluated the immune status of tumor microenvironments and confirmed that mature dendritic cells, helper T cells and cytotoxic T cells were highly accumulated in tumor sites under the IL-6-deficient condition. In addition, higher numbers of interferon (IFN)-γ-producing T cells were present in the tumor tissues of IL-6-deficient mice compared with wild-type mice. Surface expression levels of programmed death-ligand 1 (PD-L1) and MHC class I on CT26 cells were enhanced under the IL-6-deficient condition in vivo and by IFN-γ stimulation in vitro. Finally, we confirmed that in vivo injection of an anti-PD-L1 antibody or a Toll-like receptor 3 ligand, polyinosinic-polycytidylic acid, effectively inhibited tumorigenesis under the IL-6-deficient condition. Based on these findings, we speculate that a lack of IL-6 produced in tumor-bearing host augments induction of antitumor effector T cells and inhibits tumorigenesis in vivo, suggesting that IL-6 signaling may be a promising target for the development of effective cancer immunotherapies.

Interleukin-6/STAT3 signaling as a promising target to improve the efficacy of cancer immunotherapy.

Overcoming the immunosuppressive state in tumor microenvironments is a critical issue for improving the efficacy of cancer immunotherapy. Interleukin (IL)-6, a pleiotropic cytokine, is highly produced in the tumor-bearing host. Previous studies have indicated that IL-6 suppresses the antigen presentation ability of dendritic cells (DC) through activation of signal transducer and activator of transcription 3 (STAT3). Thus, we focused on the precise effect of the IL-6/STAT3 signaling cascade on human DC and the subsequent induction of antitumor T cell immune responses. Tumor-infiltrating CD11b+ CD11c+ cells isolated from colorectal cancer tissues showed strong induction of the IL-6 gene, downregulated surface expression of human leukocyte antigen (HLA)-DR, and an attenuated T cell-stimulating ability compared with those from peripheral blood mononuclear cells, suggesting that the tumor microenvironment suppresses antitumor effector cells. In vitro experiments revealed that IL-6-mediated STAT3 activation reduced surface expression of HLA-DR on CD14+ monocyte-derived DC. Moreover, we confirmed that cyclooxygenase 2, lysosome protease and arginase activities were involved in the IL-6-mediated downregulation of the surface expression levels of HLA class II on human DC. These findings suggest that IL-6-mediated STAT3 activation in the tumor microenvironment inhibits functional maturation of DC to activate effector T cells, blocking introduction of antitumor immunity in cancers. Therefore, we propose in this review that blockade of the IL-6/STAT3 signaling pathway and target molecules in DC may be a promising strategy to improve the efficacy of immunotherapies for cancer patients.

Natural killer T cells in adipose tissue are activated in lean mice.

Adipose tissues are closely connected with the immune system. It has been suggested that metabolic syndromes such as type 2 diabetes, arteriosclerosis and liver steatosis can be attributed to adipose tissue inflammation characterized by macrophage infiltration. To understand a physiological and pathological role of natural killer T (NKT) cells on inflammation in adipose tissue, we characterized a subset of NKT cells in abdominal and subcutaneous adipose tissues in C57BL/6J mice fed normal or high-fat diets. NKT cells comprised a larger portion of lymphocytes in adipose tissues compared with the spleen and peripheral blood, with epididymal adipose tissue having the highest number of NKT cells. Furthermore, some NKT cells in adipose tissues expressed higher levels of CD69 and intracellular interferon-γ, whereas the Vß repertoires of NKT cells in adipose tissues were similar to other cells. In obese mice fed a high-fat diet, adipose tissue inflammation had little effect on the Vß repertoire of NKT cells in epididymal adipose tissues. We speculate that the NKT cells in adipose tissues may form an equivalent subset in other tissues and that these subsets are likely to participate in adipose tissue inflammation. Additionally, the high expression level of CD69 and intracellular IFN-γ raises the possibility that NKT cells in adipose tissue may be stimulated by some physiological mechanism.

Differentiation of neural cells in the fetal cerebral cortex of cynomolgus monkeys (Macaca fascicularis).

Proliferation and programmed cell death are important in the formation of morphologic structures and functional activity during CNS development. We used immunohistochemical and TUNEL methods to examine the proliferation and differentiation of neural cells in, distribution of apoptotic cells in, and microglial cell involvement in the removal of apoptotic cells from the fetal cerebral cortex of cynomolgus monkeys. At embryonic day (E) 50 and E80, the neuroepithelium contained many mitotic cells. Cells staining for PCNA (a nuclear marker of proliferating cells) were prominent in the proliferative zone, whereas cells positive for NeuN (a neuron-specific marker) were absent. GFAP staining for glial cells was positive in the neuroepithelium and radial glial fibers. Iba1-positive cells (that is, macrophages and microglia) were distributed throughout all regions at all time points but accumulated especially in the ventricular zone at E80. Apoptotic morphology (at E80) and TUNEL-positive cells (that is, containing DNA fragmentation; at E50 and E80) were observed also. At E120 and E150, most PCNA-positive cells were in the ventricular zone, and NeuN-positive cells were prominent in all layers except layer I-II at E120. GFAP immunoreactivity was detected mainly in cells with fine processes in the white matter. Neither apoptosis nor TUNEL-positive cells were detected at either E120 or E150. These results suggest that proliferation, migration, and neural cell death occur during midgestation (that is, E50 to E80) in fetal brain of cynomolgus macaques, whereas differentiation and maturation of neural cells occur after midgestation (E80).