The C-type lectin DCIR contributes to the immune response and pathogenesis of colorectal cancer.

Development and progression of malignancies are accompanied and influenced by alterations in the surrounding immune microenvironment. Understanding the cellular and molecular interactions between immune cells and cancer cells has not only provided important fundamental insights into the disease, but has also led to the development of new immunotherapies. The C-type lectin Dendritic Cell ImmunoReceptor (DCIR) is primarily expressed by myeloid cells and is an important regulator of immune homeostasis, as demonstrated in various autoimmune, infectious and inflammatory contexts. Yet, the impact of DCIR on cancer development remains largely unknown. Analysis of available transcriptomic data of colorectal cancer (CRC) patients revealed that high DCIR gene expression is associated with improved patients' survival, immunologically "hot" tumors and high immunologic constant of rejection, thus arguing for a protective and immunoregulatory role of DCIR in CRC. In line with these correlative data, we found that deficiency of DCIR1, the murine homologue of human DCIR, leads to the development of significantly larger tumors in an orthotopic murine model of CRC. This phenotype is accompanied by an altered phenotype of tumor-associated macrophages (TAMs) and a reduction in the percentage of activated effector CD4+ and CD8+ T cells in CRC tumors of DCIR1-deficient mice. Overall, our results show that DCIR promotes antitumor immunity in CRC, making it an attractive target for the future development of immunotherapies to fight the second deadliest cancer in the world.

Local and systemic immune profiles of human pancreatic ductal adenocarcinoma revealed by single-cell mass cytometry.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy in need of effective (immuno)therapeutic treatment strategies. For the optimal application and development of cancer immunotherapies, a comprehensive understanding of local and systemic immune profiles in patients with PDAC is required. Here, our goal was to decipher the interplay between local and systemic immune profiles in treatment-naïve patients with PDAC. METHODS: The immune composition of PDAC, matched non-malignant pancreatic tissue, regional lymph nodes, spleen, portal vein blood, and peripheral blood samples (collected before and after surgery) from 11 patients with PDAC was assessed by measuring 41 immune cell markers by single-cell mass cytometry. Furthermore, the activation potential of tumor-infiltrating lymphocytes as determined by their ability to produce cytokines was investigated by flow cytometry. In addition, the spatial localization of tumor-infiltrating innate lymphocytes in the tumor microenvironment was confirmed by multispectral immunofluorescence. RESULTS: We found that CD103+CD8+ T cells with cytotoxic potential are infrequent in the PDAC immune microenvironment and lack the expression of activation markers and checkpoint blockade molecule programmed cell death protein-1 (PD-1). In contrast, PDAC tissues showed a remarkable increased relative frequency of B cells and regulatory T cells as compared with non-malignant pancreatic tissues. Besides, a previously unappreciated innate lymphocyte cell (ILC) population (CD127-CD103+CD39+CD45RO+ ILC1-like) was discovered in PDAC tissues. Strikingly, the increased relative frequency of B cells and regulatory T cells in pancreatic cancer samples was reflected in matched portal vein blood samples but not in peripheral blood, suggesting a regional enrichment of immune cells that infiltrate the PDAC microenvironment. After surgery, decreased frequencies of myeloid dendritic cells were found in peripheral blood. CONCLUSIONS: Our work demonstrates an immunosuppressive landscape in PDAC tissues, generally deprived of cytotoxic T cells and enriched in regulatory T cells and B cells. The antitumor potential of ILC1-like cells in PDAC may be exploited in a therapeutic setting. Importantly, immune profiles detected in blood isolated from the portal vein reflected the immune cell composition of the PDAC microenvironment, suggesting that this anatomical location could be a source of tumor-associated immune cell subsets.

Mesh, flap or combined repair of perineal hernia after abdominoperineal resection - A systematic review and meta-analysis.

AIM: The aim of this systematic review was to analyse recurrence rates after different surgical techniques for perineal hernia repair. METHOD: All original studies (n ≥ 2 patients) reporting recurrence rates after perineal hernia repair after abdominoperineal resection (APR) were included. The electronic database PubMed was last searched in December 2021. The primary outcome was recurrent perineal hernia. A weighted average of the logit proportions was determined by the use of the generic inverse variance method and random effects model. RESULTS: A total of 19 studies involving 172 patients were included. The mean age of patients was 64 ± 5.6 years and the indication for APR was predominantly cancer (99%, 170/172). The pooled percentage of recurrent perineal hernia was 39% (95% CI: 27%-52%) after biological mesh closure, 29% (95% CI: 21%-39%) after synthetic mesh closure, 37% (95% CI: 14%-67%) after tissue flap reconstruction only and 9% (95% CI: 1%-45%) after tissue flap reconstruction combined with mesh. CONCLUSION: Recurrence rates after mesh repair of perineal hernia are high, without a clear difference between biological and synthetic meshes. The addition of a tissue flap to mesh repair seemed to have a favourable outcome, which warrants further investigation.

The identification of the anthracycline aclarubicin as an effective cytotoxic agent for pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of cancer, mainly due to its delayed diagnosis and lack of effective therapeutic options. Therefore, it is imperative to find novel treatment options for PDAC. Here, we tested a series of conventional chemotherapeutics together with anthracycline compounds as single agents or in combination, determining their effectivity against established commercial and patient-derived, low-passage PDAC cell lines. Proliferation and colony formation assays were performed to determine the anticancer activity of anthracyclines; aclarubicin and doxorubicin, on commercial and patient-derived, low-passage PDAC cell lines. In addition, the effect of standard-of-care drugs gemcitabine and individual components of FOLFIRINOX were also investigated. To evaluate which mechanisms of cell death were involved in drug response, cleavage of poly(ADP-ribose)polymerase was evaluated by western blot. Aclarubicin showed superior antitumor activity compared to other anthracyclines and standard of care drugs (gemcitabine and individual components of FOLFIRINOX) in a patient-derived, low-passage PDAC cell line and in commercial cell lines. Importantly, the combination of gemcitabine and aclarubicin showed a synergistic effect at a dose range where the single agents by themselves were ineffective. In parallel, evaluation of the antitumor activity of aclarubicin demonstrated an apoptotic effect in all PDAC cell lines. Aclarubicin is cytotoxic for commercial and patient-derived low-passage PDAC cell lines, at doses lower than peak serum concentrations for patient treatment. Our findings support a (re)consideration of aclarubicin as a backbone of new combination regimens for pancreatic cancer patients.

Immunotherapy for pancreatic cancer: chasing the light at the end of the tunnel.

BACKGROUND: Checkpoint blockade immunotherapy has had a significant impact on the survival of a subset of patients with advanced cancers. It has been particularly effective in immunogenic cancer types that present large numbers of somatic mutations in their genomes. To date, all conventional immunotherapies have failed to produce significant clinical benefits for patients diagnosed with pancreatic cancer, probably due to its poor immunogenic properties, including low numbers of neoantigens and highly immune-suppressive microenvironments. CONCLUSIONS: Herein, we discuss advances that have recently been made in cancer immunotherapy and the potential of this field to deliver effective treatment options for pancreatic cancer patients. Preclinical investigations, combining different types of therapies, highlight possibilities to enhance anti-tumor immunity and to generate meaningful clinical responses in pancreatic cancer patients. Results from completed and ongoing (pre)clinical trials are discussed.

Correction to: Molecular and pharmacological modulators of the tumor immune contexture revealed by deconvolution of RNA-seq data.

It was highlighted that the original article [1] contained a typesetting mistake in the name of Noel Filipe da Cunha Carvalho de Miranda. This was incorrectly captured as Noel Filipe da Cunha Carvahlo de Miranda. It was also highlighted that in Fig. 3C the left panels Y-axis were cropped and in Fig. 5C, CD8 bar was cropped. This Correction article shows the correct Figs. 3 and 5. The original article has been updated.

Molecular and pharmacological modulators of the tumor immune contexture revealed by deconvolution of RNA-seq data.

We introduce quanTIseq, a method to quantify the fractions of ten immune cell types from bulk RNA-sequencing data. quanTIseq was extensively validated in blood and tumor samples using simulated, flow cytometry, and immunohistochemistry data.quanTIseq analysis of 8000 tumor samples revealed that cytotoxic T cell infiltration is more strongly associated with the activation of the CXCR3/CXCL9 axis than with mutational load and that deconvolution-based cell scores have prognostic value in several solid cancers. Finally, we used quanTIseq to show how kinase inhibitors modulate the immune contexture and to reveal immune-cell types that underlie differential patients' responses to checkpoint blockers.Availability: quanTIseq is available at http://icbi.at/quantiseq .

Cancer immunophenotyping by seven-colour multispectral imaging without tyramide signal amplification.

Checkpoint blockade immunotherapies have revolutionised cancer treatment in the last decade. Nevertheless, these are only beneficial for a small proportion of cancer patients. Important prognosticators for response to immunotherapy are the mutation burden of tumours as well as the quality and quantity of tumour-infiltrating immune cells. High-throughput multiplex immunophenotyping technologies have a central role in deciphering the complexity of anti-tumour immune responses. Current techniques for the immunophenotyping of solid tumours are held back by the lack of spatial context, limitations in the number of targets that can be visualised simultaneously, and/or cumbersome protocols. We developed a tyramide signal amplification-free method for the simultaneous detection of seven cellular targets by immunofluorescence. This method overcomes limitations posed by most widespread techniques and provides a unique tool for extensive phenotyping by multispectral fluorescence microscopy. Furthermore, it can be easily implemented as a high-throughput technology for validation of discovery sets generated by RNA sequencing or mass cytometry and may serve in the future as a complementary diagnostic tool.

Autologous iPSC-Based Vaccines Elicit Anti-tumor Responses In Vivo.

Cancer cells and embryonic tissues share a number of cellular and molecular properties, suggesting that induced pluripotent stem cells (iPSCs) may be harnessed to elicit anti-tumor responses in cancer vaccines. RNA sequencing revealed that human and murine iPSCs express tumor-associated antigens, and we show here a proof of principle for using irradiated iPSCs in autologous anti-tumor vaccines. In a prophylactic setting, iPSC vaccines prevent tumor growth in syngeneic murine breast cancer, mesothelioma, and melanoma models. As an adjuvant, the iPSC vaccine inhibited melanoma recurrence at the resection site and reduced metastatic tumor load, which was associated with fewer Th17 cells and increased CD11b+GR1hi myeloid cells. Adoptive transfer of T cells isolated from vaccine-treated tumor-bearing mice inhibited tumor growth in unvaccinated recipients, indicating that the iPSC vaccine promotes an antigen-specific anti-tumor T cell response. Our data suggest an easy, generalizable strategy for multiple types of cancer that could prove highly valuable in clinical immunotherapy.

Transplanted terminally differentiated induced pluripotent stem cells are accepted by immune mechanisms similar to self-tolerance.

The exact nature of the immune response elicited by autologous-induced pluripotent stem cell (iPSC) progeny is still not well understood. Here we show in murine models that autologous iPSC-derived endothelial cells (iECs) elicit an immune response that resembles the one against a comparable somatic cell, the aortic endothelial cell (AEC). These cells exhibit long-term survival in vivo and prompt a tolerogenic immune response characterized by elevated IL-10 expression. In contrast, undifferentiated iPSCs elicit a very different immune response with high lymphocytic infiltration and elevated IFN-γ, granzyme-B and perforin intragraft. Furthermore, the clonal structure of infiltrating T cells from iEC grafts is statistically indistinguishable from that of AECs, but is different from that of undifferentiated iPSC grafts. Taken together, our results indicate that the differentiation of iPSCs results in a loss of immunogenicity and leads to the induction of tolerance, despite expected antigen expression differences between iPSC-derived versus original somatic cells.