Immunosuppressive Traits of the Hybrid Epithelial/Mesenchymal Phenotype

Recent preclinical and clinical data suggests enhanced metastatic fitness of hybrid epithelial/mesenchymal (E/M) phenotypes, but mechanistic details regarding their survival strategies during metastasis remain unclear. Here, we investigate immune-evasive strategies of hybrid E/M states. We construct and simulate the dynamics of a minimalistic regulatory network encompassing the known associations among regulators of EMT (epithelial-mesenchymal transition) and PD-L1, an established immune-suppressor. Our simulations for the network consisting of SLUG, ZEB1, miR-200, CDH1 and PD-L1, integrated with single-cell and bulk RNA-seq data analysis, elucidate that hybrid E/M cells can have high levels of PD-L1, similar to those seen in cells with a full EMT phenotype, thus obviating the need for cancer cells to undergo a full EMT to be immune-evasive. Specifically, in breast cancer, we show the co-existence of hybrid E/M phenotypes, enhanced resistance to anti-estrogen therapy and increased PD-L1 levels. Our results underscore how the emergent dynamics of interconnected regulatory networks can coordinate different axes of cellular fitness during metastasis.

Chemogenetic modulation of sensory neurons reveals their regulating role in melanoma progression

Sensory neurons have recently emerged as components of the tumor microenvironment. Nevertheless, whether sensory neuronal activity is important for tumor progression remains unknown. Here we used Designer Receptors Exclusively Activated by a Designer Drug (DREADD) technology to inhibit or activate sensory neurons’ firing within the melanoma tumor. Melanoma growth and angiogenesis were accelerated following inhibition of sensory neurons’ activity and were reduced following overstimulation of these neurons. Sensory neuron-specific overactivation also induced a boost in the immune surveillance by increasing tumor-infiltrating anti-tumor lymphocytes, while reducing immune-suppressor cells. In humans, a retrospective in silico analysis of melanoma biopsies revealed that increased expression of sensory neurons-related genes within melanoma was associated with improved survival. These findings suggest that sensory innervations regulate melanoma progression, indicating that manipulation of sensory neurons’ activity may provide a valuable tool to improve melanoma patients’ outcomes.

Myeloid-derived suppressor cells and the pathogenesis of human immunodeficiency virus infection

There are several mechanisms by which human immunodeficiency virus (HIV) can mediate immune dysfunction and exhaustion during the course of infection. Chronic immune activation, after HIV infection, seems to be a key driving force of such unwanted consequences, which in turn worsens the pathological status. In such cases, the immune system is programmed to initiate responses that counteract unwanted immune activation, for example through the expansion of myeloid-derived suppressor cells (MDSCs). Although the expansion of immune suppressor cells in the setting of systemic chronic immune activation, in theory, is expected to contain immune activation, HIV infection is still associated with a remarkably high level of biomarkers of immune activation. Paradoxically, the expansion of immune suppressor cells during HIV infection can suppress potent anti-viral immune responses, which in turn contribute to viral persistence and disease progression. This indicates that HIV hijacks not only immune activation but also the immune regulatory responses to its advantage. In this work, we aim to pave the way to comprehend how such unwanted expansion of MDSCs could participate in the pathology of acute/primary and chronic HIV infection in humans, as well as simian immunodeficiency virus infection in rhesus macaques, according to the available literature.

Lower Survival and Increased Circulating Suppressor Cells in Patients with Relapsed/Refractory Diffuse Large B-Cell Lymphoma with Deficit of Vitamin D Levels Using R-GDP Plus Lenalidomide (R2-GDP): Results from the R2-GDP-GOTEL Trial

The search of prognostic factors is a priority in diffuse large B-cell lymphoma (DLBCL) due to its aggressiveness. We have recently found that the level of circulating MDSCs is a good marker of survival in a translational study based on a trial (EudraCT Number: 2014-001620-29), using lenalidomide combined with R-GDP (rituximab plus gemcitabine, cisplatin, and dexamethasone). Since Vitamin D is a known immunomodulator, we have studied blood levels of these cell populations comparing patients with deficit of vitamin D levels (<15 ng/mL with those with normal levels >15 ng/mL. Mann–Whitney U test was used to compare cells distributions between groups, Wilcoxon test to compare cells distribution at different times and Spearman test to measure the association between cell populations. Patients with vitamin D deficit maintained the increased level of immune suppressor cells, whereas we observed a depletion of all immune suppressor cells in patients with normal vitamin D levels. In conclusion, we have confirmed the importance of vitamin D in the response to treatment in R/R DLBCL, suggesting that vitamin D deficit may be involved in the immune deficit of these patients, and thus, vitamin D supplementation in these patients may help to obtain a better response, warranting further investigation.

Environment, rather than Hematodinium parasitization, determines collateral disease contraction in a crustacean host

Host, pathogen, and environment are determinants of the disease triangle, the latter being a key driver of disease outcomes and persistence within a community. The dinoflagellate genus Hematodinium is detrimental to crustaceans globally – considered to suppress the innate defences of hosts, making them more susceptible to co-infections. Evidence supporting immune-suppression is largely anecdotal and sourced from diffuse accounts of compromised decapods. We used a population of shore crabs (Carcinus maenas), where Hematodinium sp. is endemic, to determine the extent of collateral infections across two distinct environments (open water, semi-closed dock). Using a multi-resource approach (PCR, histology, haematology, population genetics, eDNA), we identified 162 Hematodinium- positive crabs and size/sex-matched these to 162 Hematodinium-free crabs out of 1,191 analysed. Crabs were interrogated for additional disease-causing agents; haplosporidians, microsporidians, mikrocytids, Vibrio spp., fungi, Sacculina, trematodes, and haemolymph bacterial loads. We found no significant differences in occurrence, severity or composition of collateral infections between Hematodinium-positive and Hematodinium-free crabs at either site, but crucially, we recorded site-restricted blends of pathogens. We found no gross signs of host cell immune reactivity toward Hematodinium in the presence or absence of other pathogens. We contend Hematodinium sp. is an immune-evader rather than immune-suppressor, which suggests an evolutionary drive toward latency in this environmentally plastic host.

Impact of Overexpression of Immune Suppressor Siglec-15 on The Prognosis of Clear Renal Cell Carcinoma and Fibrosis Level

Background The expression of Siglec-15, as a critical immune suppressor, in renal clear cell carcinoma (ccRCC) was few evaluated and remains unclear, especially in protein level. As previous studies reported, tumor fibrosis plays an essential role in assessing the prognosis of ccRCC, but the exact mechanism is not precise. This study evaluated the expression of Siglec-15, its role in prognosis, and the association with tumor fibrosis in ccRCC.Methods: Immunohistochemistry was used to analyze the Siglec-15 expression in one tissue microarray (cohort A, tumor: n=134, adjacent normal tissues: n=29). Subsequently, the mRNA expression of Siglec-15 and its clinical significance in ccRCC were analyzed using The Cancer Genome Atlas database (TCGA, cohort B, n = 534) and samples. Spearman correlation coefficients were calculated for correlation analysis of correlated expression genes of Siglec-15, and then functional annotation analysis was obtained with correlated expression genes. We detected the tumor fibrosis grade in cohort C (n=32) via second harmonic generation/two-photon excitation fluorescence. Results: Siglec-15 was overexpressed in tumor tissues compared with adjacent normal tissues in both cohort A (n=29, p<0.001) and cohort C (n=25, p<0.001). However, there was no significant difference in mRNA expression of Siglec-15 between tumor and adjacent normal tissues in cohort B (p>0.05). Moreover, over-expression of Siglec-15 is associated with higher Fuhrman grade in cohort A＆C (n=166, p=0.001, OR=3.132, 1.563-6.275), cohort B (n=534, p=0.008, OR=1.606, 1.138-2.267). Univariate Kaplan-Meir survival analysis showed that patients with high Siglec-15 mRNA expression had shorter survival periods without significance in cohort B (p=0.073). Multivariate analysis employing the Siglec-15 regression model revealed that AJCC and Fuhrman grade was the only significant independent prognostic indicators. Besides, an inverse correlation was found between Siglec-15 protein expression and the tumor's fibrosis level (p = 0.02).Conclusions: Siglec-15 expression increases in ccRCC compared with adjacent normal tissues. Siglec-15 was frequently expressed and positively associated with pathology grade in ccRCC. This study indicated a significant role of Siglec-15 in the prognosis and immunotherapy target of ccRCC. This study also found an inverse correlation between Siglec-15 protein expression and the fibrosis level of the tumor.

Targeting MDSC for Immune-Checkpoint Blockade in Cancer Immunotherapy: Current Progress and New Prospects

Immune-checkpoint blockade (ICB) demonstrated inspiring effect and great promise in anti-cancer therapy. However, many obstacles, such as drug resistance and difficulty in patient selection, limited the efficacy of ICB therapy and awaited to be overcome. By timely identification and intervention of the key immune-suppressive promotors in the tumor microenvironment (TME), we may better understand the mechanisms of cancer immune-escape and use novel strategies to enhance the therapeutic effect of ICB. Myeloid-derived suppressor cell (MDSC) is recognized as a major immune suppressor in the TME. In this review, we summarized the roles MDSC played in the cancer context, focusing on its negative biologic functions in ICB therapy, discussed the strategies targeted on MDSC to optimize the diagnosis and therapy process of ICB and improve the efficacy of ICB therapy against malignancies.

Preliminary Study to Explore the Immune-Enhancement Mechanism of Platycodon grandiflorus Extract through Comparative Transcriptome Analysis

Platycodon grandiflorus has huge potential medicinal applications in different diseases and immune enhancement (IE). In the past, limited studies have been conducted to decipher the molecular mechanism behind IE of Platycodon grandiflorus extract (PGE) despite the fact that IE can be one of the important factors for application of PGE in different diseases including cancer. In this study, whole transcriptome expression and subsequent analysis in PGE treated/untreated organisms were carried out to explore the molecular mechanism behind IE, and subsequently anticancer effect. Current study has the possibility of interaction of PGE treatment with diet, so further study is required to validate the results. The immunity-related genes were found to be up-regulated in the differential expression analysis, which is in line with the IE potential of PGE and the literature. Similarly, Siglec-15, the immune-suppressor gene that has recently been suggested as the normalization target in cancer, was one of the most down-regulated genes. In a set analysis with immune-suppressor genes, the high number of immune-suppressor genes were found to be down-regulated, which indicated that down-regulation of immune-suppressor genes can be the major mechanism behind the IE in PGE treatment. Identified genes, important in immunity and cancer, are highly recommended for anticancer and IE targets in future studies.

Gastroenterological complications in kidney transplant patients

Kidney transplantation is the surgical operation by which one of the two original kidneys is replaced with another healthy one donated by a compatible individual. In most cases, donors are recently deceased. There is the possibility of withdrawing a kidney from a consenting living subject. Usually, living donors are direct family members, but they could be volunteers completely unrelated to the recipient. A much-feared complication in case of kidney transplantation is the appearance of infections. These tend to arise due to immune-suppressor drugs administered as anti-rejection therapy. In this review, we describe the gastrointestinal complications that can occur in subjects undergoing renal transplantation associated with secondary pathogenic microorganisms or due to mechanical injury during surgery or to metabolic or organic toxicity correlated to anti-rejection therapy. Some of these complications may compromise the quality of life or pose a significant risk of mortality; fortunately, many of them can be prevented and treated without the stopping the immunosuppression, thus avoiding the patient being exposed to the risk of rejection episodes.

Cathelicidin-Related Antimicrobial Peptide Regulates CD73 Expression in Mouse Th17 Cells via p38

The effector function of tumor-infiltrated CD4+ T cells is readily suppressed by many types of immune regulators in the tumor microenvironment, which is one of the major mechanisms of immune tolerance against cancer. Cathelicidin-related antimicrobial peptide (CRAMP), the mouse analog of LL-37 peptide in humans, is a cationic antimicrobial peptide belonging to the cathelicidin family; however, its secretion by cancer cells and role in the tumor microenvironment (TME) remain unclear. In this study, we explored the possibility of an interaction between effector CD4+ T cells and CRAMP using in vitro-generated mouse Th17 cells. We found that CRAMP stimulates Th17 cells to express the ectonucleotidase CD73, while simultaneously inducing cell death. This finding suggested that CD73-expressing Th17 cells may function as immune suppressor cells instead of effector cells. In addition, treatment of pharmacological inhibitors of the transforming growth factor-beta (TGF-β) signaling pathway showed that induction of CD73 expression is mediated by the p38 signaling pathway. Overall, our findings suggest that tumor-derived LL-37 likely functions as an immune suppressor that induces immune tolerance against tumors through shaping effector Th17 cells into suppressor Th17 cells, suggesting a new intervention target to improve cancer immunotherapy.