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Background: The apoptosis-inducing serine protease granzyme B (GrB) is an important factor contributing to lysis of target cells by cytotoxic lymphocytes. Expression of enzymatically active GrB in recombinant form is a prerequisite for functional analysis and application of GrB for therapeutic purposes. Methods and Findings: We investigated the influence of bacterial maltose-binding protein (MBP) fused to GrB via a synthetic furin recognition motif on the expression of the MBP fusion protein also containing an N-terminal alpha-factor signal peptide in the yeast Pichia pastoris. MBP markedly enhanced the amount of GrB secreted into culture supernatant, which was not the case when GrB was fused to GST. MBP-GrB fusion protein was cleaved during secretion by an endogenous furin-like proteolytic activity in vivo, liberating enzymatically active GrB without the need of subsequent in vitro processing. Similar results were obtained upon expression of a recombinant fragment of the ErbB2/HER2 receptor protein or GST as MBP fusions. Conclusions: Our results demonstrate that combination of MBP as a solubility enhancer with specific in vivo cleavage augments secretion of processed and functionally active proteins from yeast. This strategy may be generally applicable to improve folding and increase yields of recombinant proteins.
The demand to develop convergent technology platforms, such as bio-functionalized medical devices, is rapidly increasing. However, the loss of biological function of the effector molecules during sterilization represents a significant and general problem. Therefore, we have developed and characterized a nano-coating (NC) formulation capable of maintaining the functionality of proteins on biological-device combination products. As a proof of concept, the NC preserved the structural and functional integrity of an otherwise highly fragile antibody immobilized on polyurethane during deleterious sterilizing irradiation (≥ 25 kGy). The NC procedure enables straight-forward terminal sterilization of bio-functionalized materials while preserving optimal conditioning of the bioactive surface.
Macrophages not only represent an integral part of innate immunity but also critically contribute to tissue and organ homeostasis. Moreover, disease progression is accompanied by macrophage accumulation in many cancer types and is often associated with poor prognosis and therapy resistance. Given their critical role in modulating tumor immunity in primary and metastatic brain cancers, macrophages are emerging as promising therapeutic targets. Different types of macrophages infiltrate brain cancers, including (i) CNS resident macrophages that comprise microglia (TAM-MG) as well as border-associated macrophages and (ii) monocyte-derived macrophages (TAM-MDM) that are recruited from the periphery. Controversy remained about their disease-associated functions since classical approaches did not reliably distinguish between macrophage subpopulations. Recent conceptual and technological advances, such as large-scale omic approaches, provided new insight into molecular profiles of TAMs based on their cellular origin. In this review, we summarize insight from recent studies highlighting similarities and differences of TAM-MG and TAM-MDM at the molecular level. We will focus on data obtained from RNA sequencing and mass cytometry approaches. Together, this knowledge significantly contributes to our understanding of transcriptional and translational programs that define disease-associated TAM functions. Cross-species meta-analyses will further help to evaluate the translational significance of preclinical findings as part of the effort to identify candidates for macrophage-targeted therapy against brain metastasis.
Background: On encountering a susceptible target, natural killer (NK) cells mediate cytotoxicity through highly regulated steps of directed degranulation. Cytotoxic granules converge at the microtubule organizing center and are polarized toward the immunological synapse (IS), followed by granule exocytosis. NK cell retargeting by chimeric antigen receptors (CARs) or mAbs represents a promising strategy for overcoming tumor cell resistance. However, little is known about the lytic granule dynamics of such retargeted NK cells toward NK-cell-resistant tumors.
Methods: Here, we used spinning disk confocal microscopy for live-cell imaging to analyze granule-mediated NK cell cytotoxicity in ErbB2-targeted CAR-expressing NK-92 cells (NK-92/5.28.z) and high-affinity FcR transgenic NK-92 cells plus Herceptin toward ErbB2-positive breast cancer cells (MDA-MB-453), which are resistant to parental NK-92.
Results: Unmodified NK-92 cells cocultured with resistant cancer cells showed stable conjugate formation and granule clustering, but failed to polarize granules to the IS. In contrast, retargeting by CAR or FcR+Herceptin toward the MDA-MB-453 cells enabled granule polarization to the IS, resulting in highly effective cytotoxicity. We found that in NK-92 the phosphoinositide 3-kinase pathway was activated after contact with resistant MDA-MB-453, while phospholipase C-γ (PLCγ) and mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) were not activated. In contrast, retargeting by CAR or antibody-dependent cell-mediated cytotoxicity (ADCC) provided the missing PLCγ and MEK/ERK signals.
Conclusions: These observations suggest that NK cells can create conjugates with resistant cancer cells and respond by granule clustering, but the activation signals are insufficient to induce granule polarization and consequent release of lytic enzymes. Retargeting by CAR and/or the FcR/mAb (ADCC) axis provide the necessary signals, leading to granule polarization and thereby overcoming tumor cell resistance.
Reactive oxygen species (ROS) are derivatives of molecular oxygen (O2) involved in various physiological and pathological processes. In immune cells, ROS are mediators of pivotal functions such as phagocytosis, antigen presentation and recognition, cytolysis as well as phenotypical differentiation. Furthermore, ROS exert immunosuppressive effects on T and natural killer (NK) cells which is of particular importance in the so-called “tumor microenvironment” (TME) of solid tumors. This term describes the heterogenous group of non-malignant cells including tumor-associated fibroblasts and immune cells, vascular cells, bacteria etc. by which cancer cells are surrounded and with whom they engage in functional crosstalk. Importantly, pharmacological targeting of the TME and, specifically, tumor-associated immune cells utilizing immune checkpoint inhibitors - monoclonal antibodies that mitigate immunosuppression - turned out to be a major breakthrough in the treatment of malignant tumors. In this review, we aim to give an overview of the role that ROS produced in tumor-associated immune cells play during initiation, progression and metastatic outgrowth of solid cancers. Finally, we summarize findings on how ROS in the TME could be targeted therapeutically to increase the efficacy of cancer immunotherapy and discuss factors determining therapeutic success of redox modulation in tumors.
Purpose: Recent advances in the treatment algorithm of locally advanced rectal cancer (LARC) have significantly improved complete response (CR) rates and disease-free survival (DFS), but therapy resistance, with its substantial impact on outcomes and survival, remains a major challenge. Our group has recently unraveled a critical role of interleukin-1α (IL-1α) signaling in activating inflammatory cancer-associated fibroblasts (iCAFs) and mediating radiation-induced senescence, extracellular matrix (ECM) accumulation, and ultimately therapy resistance. We here summarize the recently initiated ACO/ARO/AIO-21 phase I trial, testing the IL-1 receptor antagonist (IL-1 RA) anakinra in combination with fluoropyrimidine-based chemoradiotherapy (CRT) for advanced rectal cancer.
Methods/Design: The ACO/ARO/AIO-21 is an investigator-driven, prospective, open-labeled phase I drug-repurposing trial assessing the maximum tolerated dose (MTD) of capecitabine administered concurrently to standard preoperative radiotherapy (45 Gy in 25 fractions followed by 9 Gy boost in 5 fractions) in combination with fixed doses of the IL-1RA anakinra (100 mg, days −10 to 40). Capecitabine will be administered using a 3 + 3 dose-escalation design (500 mg/m2 bid; 650 mg/m2 bid; 825 mg/m2 bid, respectively) from day 1 to day 40. Response assessment including digital rectal examination (DRE), endoscopy and pelvic magnetic resonance imaging (MRI) is scheduled 10 weeks after completion of CRT. For patients achieving clinical complete response (cCR), primary non-operative management is provided. In case of non-cCR immediate total mesorectal excision (TME) will be performed. Primary endpoint of this phase I trial is the MTD of capecitabine.
Discussion: Based on extensive preclinical research, the ACO/ARO/AIO-21 phase I trial will assess whether the IL-1RA anakinra can be safely combined with fluoropyrimidine-based CRT in rectal cancer. It will further explore the potential of IL-1 inhibition to overcome therapy resistance and improve response rates. A comprehensive translational research program will expand our understanding from a clinical perspective and may help translate the results into a randomized phase II trial.
Radiobiology research in rectal cancer has been limited to cell lines, patient-derived organoids (PDOs), or xenografts. Here, we describe a protocol which recapitulates more efficiently the complex contributions of the tumor microenvironment. This approach establishes a preclinical mouse model of rectal cancer by intrarectal transplantation of genetically modified organoids into immunocompetent mice followed by precise image-guided radiotherapy (IGRT) of organoid-induced tumors. This model represents a useful platform to study the cellular and molecular determinants of therapy resistance in rectal cancer.
Background: The inclusion of immune checkpoint inhibitors (ICIs) in therapeutic algorithms has led to significant survival benefits in patients with various metastatic cancers. Concurrently, an increasing number of neurological immune related adverse events (IRAE) has been observed. In this retrospective analysis, we examine the ICI-induced incidence of cerebral pseudoprogression and propose a classification system.
Methods: We screened our hospital information system to identify patients with any in-house ICI treatment for any tumor disease during the years 2007-2019. All patients with cerebral MR imaging (cMRI) of sufficient diagnostic quality were included. cMRIs were retrospectively analyzed according to immunotherapy response assessment for neuro-oncology (iRANO) criteria.
Results: We identified 12 cases of cerebral pseudoprogression in 123 patients treated with ICIs and sufficient MRI. These patients were receiving ICI therapy for lung cancer (n=5), malignant melanoma (n=4), glioblastoma (n=1), hepatocellular carcinoma (n=1) or lymphoma (n=1) when cerebral pseudoprogression was detected. Median time from the start of ICI treatment to pseudoprogression was 5 months. All but one patient developed neurological symptoms. Three different patterns of cerebral pseudoprogression could be distinguished: new or increasing contrast-enhancing lesions, new or increasing T2 predominant lesions and cerebral vasculitis type pattern.
Conclusion: Cerebral pseudoprogression followed three distinct patterns and was detectable in 3.2% of all patients during ICI treatment and in 9.75% of the patients with sufficient brain imaging follow up. The fact that all but one of the affected patients developed neurological symptoms, which would be classified as progressive disease according to iRANO criteria, mandates vigilance in the diagnosis and treatment of ICI-induced cerebral lesions.
After myocardial infarction in the adult heart the remaining, non-infarcted tissue adapts to compensate the loss of functional tissue. This adaptation requires changes in gene expression networks, which are mostly controlled by transcription regulating proteins. Long non-coding transcripts (lncRNAs) are taking part in fine-tuning such gene programs. We describe and characterize the cardiomyocyte specific lncRNA Sweetheart RNA (Swhtr), an approximately 10 kb long transcript divergently expressed from the cardiac core transcription factor coding gene Nkx2-5. We show that Swhtr is dispensable for normal heart development and function but becomes essential for the tissue adaptation process after myocardial infarction in murine males. Re-expressing Swhtr from an exogenous locus rescues the Swhtr null phenotype. Genes that depend on Swhtr after cardiac stress are significantly occupied and therefore most likely regulated by NKX2-5. The Swhtr transcript interacts with NKX2-5 and disperses upon hypoxic stress in cardiomyocytes, indicating an auxiliary role of Swhtr for NKX2-5 function in tissue adaptation after myocardial injury.
Long non-coding RNAs are a very versatile class of molecules that can have important roles in regulating a cells function, including regulating other genes on the transcriptional level. One of these mechanisms is that RNA can directly interact with DNA thereby recruiting additional components such as proteins to these sites via an RNA:dsDNA triplex formation. We genetically deleted the triplex forming sequence (FendrrBox) from the lncRNA Fendrr in mice and found that this FendrrBox is partially required for Fendrr function in vivo. We found that the loss of the triplex forming site in developing lungs causes a dysregulation of gene programs associated with lung fibrosis. A set of these genes contain a triplex site directly at their promoter and are expressed in lung fibroblasts. We biophysically confirmed the formation of an RNA:dsDNA triplex with target promoters in vitro. We found that Fendrr with the Wnt signalling pathway regulates these genes, implicating that Fendrr synergizes with Wnt signalling in lung fibrosis.