The immunosuppressive tumor microenvironment represents not only one of the key factors stimulating tumor progression but also a strong obstacle for efficient tumor immunotherapy. Immunosuppression ...was found to be associated with chronic inflammatory mediators including cytokines, chemokines and growth factors produced by cancer and stroma cells. Long-term intensive production of these factors induces the formation of myeloid-derived suppressor cells (MDSCs) representing one of the most important players mediating immunosuppression. Moreover, MDSCs could not only inhibit anti-tumor immune reactions but also directly stimulate tumor growth and metastasis. Therefore, understanding the mechanisms of their generation, expansion, recruitment and activation is required for the development of novel strategies for tumor immunotherapy.
Pluripotent stem cells have been generated from mouse and human somatic cells by viral expression of the transcription factors Oct4, Sox2, Klf4, and c-Myc. A major limitation of this technology is ...the use of potentially harmful genome-integrating viruses. We generated mouse induced pluripotent stem (iPS) cells from fibroblasts and liver cells by using nonintegrating adenoviruses transiently expressing Oct4, Sox2, Klf4, and c-Myc. These adenoviral iPS (adeno-iPS) cells show DNA demethylation characteristic of reprogrammed cells, express endogenous pluripotency genes, form teratomas, and contribute to multiple tissues, including the germ line, in chimeric mice. Our results provide strong evidence that insertional mutagenesis is not required for in vitro reprogramming. Adenoviral reprogramming may provide an improved method for generating and studying patient-specific stem cells and for comparing embryonic stem cells and iPS cells.
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Accumulation of myeloid-derived suppressor cells (MDSC) in melanoma microenvironment is supported by chemokine receptor/chemokine signaling. Although different chemokines were suggested to be ...involved in this process, the role of CCR5 and its ligands is not established. Using a
transgenic mouse melanoma model, we found an accumulation of CCR5
MDSCs in melanoma lesions associated with both increased concentrations of CCR5 ligands and tumor progression. Tumor-infiltrating CCR5
MDSCs displayed higher immunosuppressive activity than their CCR5
counterparts. Upregulation of CCR5 expression on CD11b
Gr1
myeloid cells was induced
by CCR5 ligands and other inflammatory factors. In melanoma patients, CCR5
MDSCs were enriched at the tumor site and correlated with enhanced production of CCR5 ligands. Moreover, they exhibited a stronger immunosuppressive pattern compared with CCR5
MDSCs. Blocking CCR5/CCR5 ligand interactions increased survival of tumor-bearing mice and was associated with reduced migration and immunosuppressive potential of MDSCs in tumor lesions. Our findings define a critical role for CCR5 in recruitment and activation of MDSCs, suggesting a novel strategy for melanoma treatment.
These findings validate the importance of the CCR5/CCR5 ligand axis not only for MDSC recruitment but also for further activation of their immunosuppressive functions in the tumor microenvironment, with potentially broad therapeutic implications, given existing clinically available inhibitors of this axis.
.
SOX2
is a gene that encodes for a transcription factor belonging to the
SOX
gene family and contains a high-mobility group (HMG) domain, which permits highly specific DNA binding. Consequently, SOX2 ...functions as an activator or suppressor of gene transcription.
SOX2
has been described as an essential embryonic stem cell gene and moreover, a necessary factor for induced cellular reprogramming.
SOX2
research has only recently switched focus from embryogenesis and development to SOX2’s function in disease. Particularly, the role of
SOX2
in cancer pathogenesis has become of interest in the field. To date, studies have shown SOX2 to be amplified in various cancer types and affect cancer cell physiology
via
involvement in complicated cell signaling and protein-protein interactions. Recent reviews in this field have highlighted SOX2 in mammalian physiology, development and pathology. In this review, we comprehensively compile what is known to date about SOX2’s involvement in cancer biology, focusing on the most recent findings in the fields of cellular signaling and cancer stem cells. Lastly, we underscore the role of SOX2 in the clinic and highlight new findings, which may provide novel clinical applications for SOX2 as a prognostic marker, indicator of metastasis, biomarker or potential therapeutic target in some cancer types.
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The diagnosis of most cancers is made by a board-certified pathologist based on a tissue biopsy under the microscope. Recent research reveals a high discordance between individual pathologists. For ...melanoma, the literature reports on 25–26% of discordance for classifying a benign nevus versus malignant melanoma. A recent study indicated the potential of deep learning to lower these discordances. However, the performance of deep learning in classifying histopathologic melanoma images was never compared directly to human experts. The aim of this study is to perform such a first direct comparison.
A total of 695 lesions were classified by an expert histopathologist in accordance with current guidelines (350 nevi/345 melanoma). Only the haematoxylin & eosin (H&E) slides of these lesions were digitalised via a slide scanner and then randomly cropped. A total of 595 of the resulting images were used to train a convolutional neural network (CNN). The additional 100 H&E image sections were used to test the results of the CNN in comparison to 11 histopathologists. Three combined McNemar tests comparing the results of the CNNs test runs in terms of sensitivity, specificity and accuracy were predefined to test for significance (p < 0.05).
The CNN achieved a mean sensitivity/specificity/accuracy of 76%/60%/68% over 11 test runs. In comparison, the 11 pathologists achieved a mean sensitivity/specificity/accuracy of 51.8%/66.5%/59.2%. Thus, the CNN was significantly (p = 0.016) superior in classifying the cropped images.
With limited image information available, a CNN was able to outperform 11 histopathologists in the classification of histopathological melanoma images and thus shows promise to assist human melanoma diagnoses.
•A convolutional neural network (CNN) was trained with 595 histopathologic images of melanoma and nevi.•In a direct comparison, the CNN and 11 histopathologists classified a test set of 100 additional histopathologic images (1:1 melanoma/nevi).•The CNN systematically outperformed the 11 histopathologists in terms of overall accuracy, sensitivity and specificity (p = 0.016).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Immune checkpoint inhibitors (ICI) used for cancer immunotherapy were shown to boost the existing anti-tumor immune response by preventing the inhibition of T cells by tumor cells. Antibodies ...targeting two negative immune checkpoint pathways, namely cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), and programmed cell death-ligand 1 (PD-L1), have been approved first for patients with melanoma, squamous non-small cell lung cancer (NSCLC), and renal cell carcinoma. Clinical trials are ongoing to verify the efficiency of these antibodies for other cancer types and to evaluate strategies to block other checkpoint molecules. However, a number of patients do not respond to this treatment possibly due to profound immunosuppression, which is mediated partly by myeloid-derived suppressor cells (MDSC). This heterogeneous population of immature myeloid cells can strongly inhibit anti-tumor activities of T and NK cells and stimulate regulatory T cells (Treg), leading to tumor progression. Moreover, MDSC can contribute to patient resistance to immune checkpoint inhibition. Accumulating evidence demonstrates that the frequency and immunosuppressive function of MDSC in cancer patients can be used as a predictive marker for therapy response. This review focuses on the role of MDSC in immune checkpoint inhibition and provides an analysis of combination strategies for MDSC targeting together with ICI to improve their therapeutic efficiency in cancer patients.
•IL-6 is a crucial regulator of myeloid-derived suppressor cells during tumor progression.•IL-6 blockade could be considered as an immunotherapeutic strategy in cancer.•Immunostimulatory effects of ...IL-6 in cancer should not be neglected.
Myeloid-derived suppressor cells (MDSC) are generated during tumor progression and suppress the anti-tumor functions of T and natural killer (NK) cells. Their enrichment is associated with a bad prognosis and a worse outcome of immunotherapy in cancer patients. The cytokine interleukin (IL)-6 was found to be a crucial regulator of MDSC accumulation and activation as well as a factor, stimulating tumor cell proliferation, survival, invasiveness and metastasis. Accordingly, IL-6 can serve as a negative prognostic marker in cancer. On the other hand, this cytokine is also involved in T cell activation. This review discusses the pleiotropic effects of IL-6 on immune cell populations that are critical for tumor development, such as MDSC and T cells, and summarizes the data on targeting IL-6 or IL-6 receptor (IL-6R) for tumor immunotherapy to block MDSC-mediated immunosuppression in cancer patients.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The immune system has many sophisticated mechanisms to balance an extensive immune response. Distinct immunosuppressive cells could protect from excessive tissue damage and autoimmune disorders. ...Tumor cells take an advantage of those immunosuppressive mechanisms and establish a strongly immunosuppressive tumor microenvironment (TME), which inhibits antitumor immune responses, supporting the disease progression. Myeloid-derived suppressor cells (MDSC) play a crucial role in this immunosuppressive TME. Those cells represent a heterogeneous population of immature myeloid cells with a strong immunosuppressive potential. They inhibit an antitumor reactivity of T cells and NK cells. Furthermore, they promote angiogenesis, establish pre-metastatic niches, and recruit other immunosuppressive cells such as regulatory T cells. Accumulating evidences demonstrated that the enrichment and activation of MDSC correlated with tumor progression, recurrence, and negative clinical outcome. In the last few years, various preclinical studies and clinical trials targeting MDSC showed promising results. In this review, we discuss different therapeutic approaches on MDSC targeting to overcome immunosuppressive TME and enhance the efficiency of current tumor immunotherapies.
Malignant melanoma is characterized by the development of chronic inflammation in the tumor microenvironment, leading to the accumulation of myeloid-derived suppressor cells (MDSCs). Using
ret
...transgenic mouse melanoma model, we found a significant migration of MDSCs expressing C-C chemokine receptor (CCR)5 into primary tumors and metastatic lymph nodes, which was correlated with tumor progression. An increased CCR5 expression on MDSCs was associated with elevated concentrations of CCR5 ligands in melanoma microenvironment.
In vitro
experiments showed that the upregulation of CCR5 expression on CD11b
+
Gr1
+
immature myeloid cells was induced by CCR5 ligands, IL-6, GM-CSF, and other inflammatory factors. Furthermore, CCR5
+
MDSCs infiltrating melanoma lesions displayed a stronger immunosuppressive pattern than their CCR5
−
counterparts. Targeting CCR5/CCR5 ligand signaling via a fusion protein mCCR5-Ig, which selectively binds and neutralizes all three CCR5 ligands, increased the survival of tumor-bearing mice. This was associated with a reduced migration and immunosuppressive potential of tumor MDSCs. In melanoma patients, circulating CCR5
+
MDSCs were increased as compared to healthy donors. Like in melanoma-bearing mice, we observed an enrichment of these cells and CCR5 ligands in tumors as compared to the peripheral blood. Our findings define a critical role for CCR5 not only in the recruitment but also in the activation of MDSCs in tumor lesions, suggesting that novel strategies of melanoma treatment could be based on blocking CCR5/CCR5 ligand interactions.
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EMUNI, FZAB, GEOZS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
10.
Melanoma Cellular Plasticity Novak, Daniel; Utikal, Jochen
International journal of molecular sciences,
06/2022, Volume:
23, Issue:
12
Journal Article
Peer reviewed
Open access
Despite the advances of modern medicine and the development of innovative and promising new therapeutic strategies for the treatment of the numerous types of cancer, far too many patients still lose ...the battle against these devastating diseases ...
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