A noninvasive photoactivatable split-Cre recombinase system for genome engineering in zebrafish.

The cyclic recombinase (Cre)/ recombination system is a powerful technique for cell labeling and tracking. However, achieving high spatiotemporal precision in cell tracking using this system is challenging due to the requirement for reliable tissue-specific promoters. In contrast, light-inducible systems offer superior regional confinement, tunability, and non-invasiveness compared to conventional lineage-tracing methods.

Definitive hematopoiesis is dispensable to sustain erythrocytes and macrophages during zebrafish ontogeny.

In all organisms studied, from flies to humans, blood cells emerge in several sequential waves and from distinct hematopoietic origins. However, the relative contribution of these ontogenetically distinct hematopoietic waves to embryonic blood lineages and to tissue regeneration during development is yet elusive. Here, using a lineage-specific "switch and trace" strategy in the zebrafish embryo, we report that the definitive hematopoietic progeny barely contributes to erythrocytes and macrophages during early development.

Cancer stem-like cells evade CD8CD103 tumor-resident memory T (T) lymphocytes by initiating an epithelial-to-mesenchymal transition program in a human lung tumor model.

Background: Cancer stem cells (CSC) define a population of rare malignant cells endowed with 'stemness' properties, such as self-renewing, multipotency and tumorigenicity. They are responsible for tumor initiation and progression, and could be associated with resistance to immunotherapies by negatively regulating antitumor immune response and acquiring molecular features enabling escape from CD8 T-cell immunity. However, the immunological hallmarks of human lung CSC and their potential interactions with resident memory T (T) cells within the tumor microenvironment have not been investigated.

Integrin-α-mediated activation of TGF-β regulates anti-tumour CD8 T cell immunity and response to PD-1 blockade.

TGF-β is secreted in the tumour microenvironment in a latent, inactive form bound to latency associated protein and activated by the integrin α subunit. The activation of latent TGF-β by cancer-cell-expressed α re-shapes the tumour microenvironment, and this could affect patient responses to PD-1-targeting therapy. Here we show, using multiplex immunofluorescence staining in cohorts of anti-PD-1 and anti-PD-L1-treated lung cancer patients, that decreased expression of cancer cell α is associated with improved immunotherapy-related, progression-free survival, as well as with an increased density of CD8CD103 tumour-infiltrating lymphocytes.

Selection of tumor‑resistant variants following sustained natural killer cell‑mediated immune stress.

Resistance of tumor cells to cell‑mediated cytotoxicity remains an obstacle to the immunotherapy of cancer and its molecular basis is poorly understood. To investigate the acquisition of tumor resistance to cell‑mediated cytotoxicity, resistant variants were selected following long‑term natural killer (NK) cell selection pressure. It was observed that these variants were resistant to NK cell‑mediated lysis, but were sensitive to autologous cytotoxic T lymphocytes or cytotoxic drugs.

Regulation of antitumour CD8 T-cell immunity and checkpoint blockade immunotherapy by Neuropilin-1.

Neuropilin-1 (Nrp-1) is a marker for murine CD4FoxP3 regulatory T (Treg) cells, a subset of human CD4 Treg cells, and a population of CD8 T cells infiltrating certain solid tumours. However, whether Nrp-1 regulates tumour-specific CD8 T-cell responses is still unclear. Here we show that Nrp-1 defines a subset of CD8 T cells displaying PD-1 status and infiltrating human lung cancer.

Human preprocalcitonin self-antigen generates TAP-dependent and -independent epitopes triggering optimised T-cell responses toward immune-escaped tumours.

Tumours often evade CD8 T-cell immunity by downregulating TAP. T-cell epitopes associated with impaired peptide processing are immunogenic non-mutated neoantigens that emerge during tumour immune evasion. The preprocalcitonin (ppCT) neoepitope belongs to this category of antigens.

Acquisition of tumor cell phenotypic diversity along the EMT spectrum under hypoxic pressure: Consequences on susceptibility to cell-mediated cytotoxicity.

Tumor escape to immunosurveillance and resistance to immune attacks present a major hurdle in cancer therapy, especially in the current era of new cancer immunotherapies. We report here that hypoxia, a hallmark of most solid tumors, orchestrates carcinoma cell heterogeneity through the induction of phenotypic diversity and the acquisition of distinct epithelial-mesenchymal transition (EMT) states. Using lung adenocarcinoma cells derived from a non-metastatic patient, we demonstrated that hypoxic stress induced phenotypic diversity along the EMT spectrum, with induction of EMT transcription factors (EMT-TFs) SNAI1, SNAI2, TWIST1, and ZEB2 in a hypoxia-inducible factor-1α (HIF1A)-dependent or -independent manner.

Regulation of Melanoma Progression through the TCF4/miR-125b/NEDD9 Cascade.

Melanoma progression from a primary lesion to a distant metastasis is a complex process associated with genetic alterations, epigenetic modifications, and phenotypic switches. Elucidation of these phenomena may indicate how to interfere with this fatal disease. The role of microRNAs as key negative regulators of gene expression, controlling all cellular processes including cell migration and invasion, is now being recognized.

TGFβ Signaling Intersects with CD103 Integrin Signaling to Promote T-Lymphocyte Accumulation and Antitumor Activity in the Lung Tumor Microenvironment.

Homing of CD8(+) T lymphocytes to the tumor microenvironment is an important step for mounting a robust antitumor immune response. TGFβ is responsible for CD103 (αEβ7) integrin induction in activated intraepithelial CD8(+) T lymphocytes. However, the interplay between TGFβ and CD103 and their contribution to T-cell infiltration and antitumor activity remain unknown.

A caveolin-dependent and PI3K/AKT-independent role of PTEN in β-catenin transcriptional activity.

Loss of the tumour suppressor PTEN is frequent in human melanoma, results in MAPK activation, suppresses senescence and mediates metastatic behaviour. How PTEN loss mediates these effects is unknown. Here we show that loss of PTEN in epithelial and melanocytic cell lines induces the nuclear localization and transcriptional activation of β-catenin independent of the PI3K-AKT-GSK3β axis.

Granzyme B-activated p53 interacts with Bcl-2 to promote cytotoxic lymphocyte-mediated apoptosis.

Granzyme B (GzmB) plays a major role in CTLs and NK cell-mediated elimination of virus-infected cells and tumors. Human GzmB preferentially induces target cell apoptosis by cleaving the proapoptotic Bcl-2 family member Bid, which, together with Bax, induces mitochondrial outer membrane permeabilization. We previously showed that GzmB also induces a rapid accumulation of the tumor-suppressor protein p53 within target cells, which seems to be involved in GzmB-induced apoptosis.

Cutting edge: Hypoxia-induced Nanog favors the intratumoral infiltration of regulatory T cells and macrophages via direct regulation of TGF-β1.

Emerging evidence suggests a link between tumor hypoxia and immune suppression. In this study, we investigated the role of hypoxia-induced Nanog, a stemness-associated transcription factor, in immune suppression. We observed that hypoxia-induced Nanog correlated with the acquisition of stem cell-like properties in B16-F10 cells.