Serine/threonine-protein kinase BRAF, a downstream effector of the RAS oncogene along the MEK/ERK signaling pathway, has emerged as an important biological marker for diagnosis, prognosis and ...therapeutic guidance for human cancers. The high prevalence of BRAF
V600E
activating mutation in papillary thyroid carcinoma, cutaneous malignant melanoma and hairy cell leukemia implies that the mutation is an important 'driver' or 'codriver' in the development of a subset of these cancers. Diagnostically, the BRAF
V600E
mutation is a powerful molecular marker for papillary thyroid carcinoma and, quite possibly, hairy cell leukemia as well. Cancers with a BRAF mutation are generally more aggressive than their counterparts without the mutation. Importantly, mutant BRAF has been a highly attractive target for precision cancer therapy. Indeed, recent studies in the clinical trials of BRAF inhibitors in patients with malignant melanoma are changing the treatment paradigm of this highly lethal disease. BRAF mutation testing using highly sensitive and specific methodology in a molecular diagnostic laboratory is essential in the current clinical practice of oncology.
Most eukaryotic cell types use a common program to regulate the process of cell division. During mitosis, successful partitioning of the genetic material depends on spatially coordinated chromosome ...movement and cell cleavage. Here we characterize a zebrafish mutant, retsina (ret), that exhibits an erythroid-specific defect in cell division with marked dyserythropoiesis similar to human congenital dyserythropoietic anemia. Erythroblasts from ret fish show binuclearity and undergo apoptosis due to a failure in the completion of chromosome segregation and cytokinesis. Through positional cloning, we show that the ret mutation is in a gene (slc4a1) encoding the anion exchanger 1 (also called band 3 and AE1), an erythroid-specific cytoskeletal protein. We further show an association between deficiency in Slc4a1 and mitotic defects in the mouse. Rescue experiments in ret zebrafish embryos expressing transgenic slc4a1 with a variety of mutations show that the requirement for band 3 in normal erythroid mitosis is mediated through its protein 4.1R-binding domains. Our report establishes an evolutionarily conserved role for band 3 in erythroid-specific cell division and illustrates the concept of cell-specific adaptation for mitosis.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Therapeutic antibodies that block the programmed death-1 (PD-1)-programmed death-ligand 1 (PD-L1) pathway can induce robust and durable responses in patients with various cancers, including ...metastatic urothelial cancer. However, these responses only occur in a subset of patients. Elucidating the determinants of response and resistance is key to improving outcomes and developing new treatment strategies. Here we examined tumours from a large cohort of patients with metastatic urothelial cancer who were treated with an anti-PD-L1 agent (atezolizumab) and identified major determinants of clinical outcome. Response to treatment was associated with CD8
T-effector cell phenotype and, to an even greater extent, high neoantigen or tumour mutation burden. Lack of response was associated with a signature of transforming growth factor β (TGFβ) signalling in fibroblasts. This occurred particularly in patients with tumours, which showed exclusion of CD8
T cells from the tumour parenchyma that were instead found in the fibroblast- and collagen-rich peritumoural stroma; a common phenotype among patients with metastatic urothelial cancer. Using a mouse model that recapitulates this immune-excluded phenotype, we found that therapeutic co-administration of TGFβ-blocking and anti-PD-L1 antibodies reduced TGFβ signalling in stromal cells, facilitated T-cell penetration into the centre of tumours, and provoked vigorous anti-tumour immunity and tumour regression. Integration of these three independent biological features provides the best basis for understanding patient outcome in this setting and suggests that TGFβ shapes the tumour microenvironment to restrain anti-tumour immunity by restricting T-cell infiltration.
Recent single-cell studies of cancer in both mice and humans have identified the emergence of a myofibroblast population specifically marked by the highly restricted leucine-rich-repeat-containing ...protein 15 (LRRC15)
. However, the molecular signals that underlie the development of LRRC15
cancer-associated fibroblasts (CAFs) and their direct impact on anti-tumour immunity are uncharacterized. Here in mouse models of pancreatic cancer, we provide in vivo genetic evidence that TGFβ receptor type 2 signalling in healthy dermatopontin
universal fibroblasts is essential for the development of cancer-associated LRRC15
myofibroblasts. This axis also predominantly drives fibroblast lineage diversity in human cancers. Using newly developed Lrrc15-diphtheria toxin receptor knock-in mice to selectively deplete LRRC15
CAFs, we show that depletion of this population markedly reduces the total tumour fibroblast content. Moreover, the CAF composition is recalibrated towards universal fibroblasts. This relieves direct suppression of tumour-infiltrating CD8
T cells to enhance their effector function and augments tumour regression in response to anti-PDL1 immune checkpoint blockade. Collectively, these findings demonstrate that TGFβ-dependent LRRC15
CAFs dictate the tumour-fibroblast setpoint to promote tumour growth. These cells also directly suppress CD8
T cell function and limit responsiveness to checkpoint blockade. Development of treatments that restore the homeostatic fibroblast setpoint by reducing the population of pro-disease LRRC15
myofibroblasts may improve patient survival and response to immunotherapy.
The response to cancer immune therapy is dependent on endogenous tumor-reactive T cells. To bypass this requirement, CD3-bispecific antibodies have been developed to induce a polyclonal T-cell ...response against the tumor. Anti-HER2/CD3 T-cell-dependent bispecific (TDB) antibody is highly efficacious in the treatment of HER2-overexpressing tumors in mice. Efficacy and immunologic effects of anti-HER2/CD3 TDB were investigated in mammary tumor model with very few T cells prior treatment. We further describe the mechanism for TDB-induced T-cell recruitment to tumors.
The immunologic effects and the mechanism of CD3-bispecific antibody-induced T-cell recruitment into spontaneous HER2-overexpressing mammary tumors was studied using human HER2 transgenic, immunocompetent mouse models.
Anti-HER2/CD3 TDB treatment induced an inflammatory response in tumors converting them from poorly infiltrated to an inflamed, T-cell abundant, phenotype. Multiple mechanisms accounted for the TDB-induced increase in T cells within tumors. TDB treatment induced CD8
T-cell proliferation. T cells were also actively recruited post-TDB treatment by IFNγ-dependent T-cell chemokines mediated via CXCR3. This active T-cell recruitment by TDB-induced chemokine signaling was the dominant mechanism and necessary for the therapeutic activity of anti-HER2/CD3 TDB.
In summary, we demonstrate that the activity of anti-HER2/CD3 TDB was not dependent on high-level baseline T-cell infiltration. Our results suggest that anti-HER2/CD3 TDB may be efficacious in patients and indications that respond poorly to checkpoint inhibitors. An active T-cell recruitment mediated by TDB-induced chemokine signaling was the major mechanism for T-cell recruitment.
Tumor-associated macrophages are composed of distinct populations arising from monocytes or tissue macrophages, with a poorly understood link to disease pathogenesis. Here, we demonstrate that mouse ...monocyte migration was supported by glutaminyl-peptide cyclotransferase-like (QPCTL), an intracellular enzyme that mediates N-terminal modification of several substrates, including the monocyte chemoattractants CCL2 and CCL7, protecting them from proteolytic inactivation. Knockout of Qpctl disrupted monocyte homeostasis, attenuated tumor growth and reshaped myeloid cell infiltration, with loss of monocyte-derived populations with immunosuppressive and pro-angiogenic profiles. Antibody targeting of the receptor CSF1R, which more broadly eliminates tumor-associated macrophages, reversed tumor growth inhibition in Qpctl
mice and prevented lymphocyte infiltration. Modulation of QPCTL synergized with anti-PD-L1 to expand CD8
T cells and limit tumor growth. QPCTL inhibition constitutes an effective approach for myeloid cell-targeted cancer immunotherapy.
Small bowel strictures remain a debilitating consequence of Crohn's disease and contribute to poor outcomes for patients. Recently, TGFβ has been identified as an important driver of intestinal ...fibrosis. We studied the localization of TGFβ isoforms in ileal strictures of patients with Crohn's disease using in situ hybridization to understand TGFβ's role in stricture formation. The mucosa of strictures was characterized by higher TGFβ1 while the stricture submucosa showed higher TGFβ3 compared to normal ileum from patients without Crohn's disease (p = 0.02 and p = 0.044, respectively). We correlated these findings with single-cell transcriptomics which demonstrated that TGFβ3 transcripts overall are very rare, which may partially explain why its role in intestinal fibrosis has remained unclear to date. There were no significant differences in fibroblast or B cell TGFβ1 and/or TGFβ3 expression in inflamed vs. noninflamed ileum. We discuss the implications of these findings for therapeutic development strategies to treat patients with fibrostenotic Crohn's disease.
2515 Background: Immunotherapeutic agents are now being investigated for treating earlier-stage cancers. Radiographic assessment by RECIST, widely used to assess treatment response in clinical trials ...for advanced cancers, has limitations in the neoadjuvant setting; and pathologic response assessment is increasingly being used as a primary and/or secondary endpoint. To that end, a pan-tumor scoring system for assessing pathologic response was developed (1,2). This scoring system allows for the quantitative assessment of residual viable tumor (RVT) in multiple locations: i.e. primary and lymph node (LN) or distant metastases, akin to RECIST. %RVT scored using this system been associated with patient outcomes after treatment with anti-PD-1-based therapies. Additionally, %RVT in LN has been shown to have additive value to %RVT in the primary tumor when predicting patient survival (3). As a result, pathologists are now being asked to score pathologic response in the primary tumor and LN as a part of ongoing clinical trials and routine clinical care. Here, we evaluated the reproducibility of %RVT scoring using pan-tumor immune-related pathologic response criteria (irPRC). Methods: A multi-institutional, international study led by the Society for Immunotherapy of Cancer was initiated to assess the concordance of pathologic response assessment in resection specimens from patients treated with anti-PD-1-based therapies. Online lecture-based modules for irPRC scoring were developed, and 14 pathologists from multiple institutions, including academic and industry partners, were trained to score H&E-stained slides. The pathologists have scored n=37 pathology cases from resection specimens and on-treatment biopsies from >10 different tumor types, in part derived from phase II/III clinical trials. %RVT in the primary tumor and LN from patient specimens were scored separately (total of n=374 slides scored by each pathologist). Results: At the first interim analysis, scoring of pathologic response using irPRC was shown to be highly reproducible, irrespective of disease location (i.e. primary tumor vs lymph node metastasis). The second half of the study is nearing completion, and these reproducibility numbers will be finalized and presented in the final abstract. Extended analyses will also be presented that include subset analyses by tumor type. Conclusions: The results will be interpreted and presented in the context of the larger field for pathologic response assessment. A post-study survey completed by the participating pathologists will be used to refine irPRC training materials prior to dissemination to the wider immuno-oncology community. 1. Cottrell et al. Ann Oncol2018. 2. Stein et al. Clin Can Res 2020. 3. Deutsch, et al. Nat Med 2023.
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