Publications by authors named "Michal Smahel"

Article Synopsis
  • Cancer immunotherapy is facing challenges due to tumors adapting and escaping the immune response, partly due to the genetic instability of tumor cells.
  • A study using a mouse model of HPV-induced tumors explored the variations in immune cell presence, gene expression, and mutations across different tumor areas post-immunotherapy.
  • Results showed an increase in mutations with significant effects on genes related to immune processes and tumor interactions, highlighting intratumoral immune heterogeneity as a factor contributing to the failure of immunotherapy.
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Three series of spiropyran photoswitches with an auxiliary chiral centre at position 3' of the indoline unit were synthesized. Using one example, a novel methodology for synthesis of an optically active spiropyran photoswitch with a defined chirality at position 3' is demonstrated. Furthermore, a new acid-mediated strategy for spiropyran purification affording moderate to excellent yields (up to 96%) is reported herein.

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Background: A proportion of head and neck carcinomas (HNSCCs) are induced by high-risk human papillomaviruses (HPVs) and are associated with better patient outcomes compared to patients with HNSCCs related to tobacco and alcohol abuse. In the microenvironment of solid tumors, including HNSCCs, oxygen levels are often reduced, and a hypoxic state is induced. This can lead to a poor treatment response and a worse patient prognosis.

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: Cancer development involves alterations in key cellular pathways, with aspartate β-hydroxylase (ASPH) emerging as an important player in tumorigenesis. ASPH is upregulated in various cancer types, where it promotes cancer progression mainly by regulating the Notch1 and SRC pathways. : This study explored the responses of various human cervical, pharyngeal, and breast tumor cell lines to second- and third-generation ASPH inhibitors (MO-I-1151 and MO-I-1182) using proliferation, migration, and invasion assays; western blotting; and cell cycle analysis.

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Background: SARS-CoV-2, which causes COVID-19, has killed more than 7 million people worldwide. Understanding the development of postinfectious and postvaccination immune responses is necessary for effective treatment and the introduction of appropriate antipandemic measures.

Objectives: We analysed humoral and cell-mediated anti-SARS-CoV-2 immune responses to spike (S), nucleocapsid (N), membrane (M), and open reading frame (O) proteins in individuals collected up to 1.

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Overexpression of aspartate β-hydroxylase (ASPH) in human tumors contributes to their progression by stimulating cell proliferation, migration, and invasion. Several signaling pathways affected by ASPH have been identified, but the high number of potential targets of ASPH hydroxylation suggests that additional mechanisms may be involved. This study was performed to reveal new targets of ASPH signaling.

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Background: Human papillomaviruses (HPVs) induce a subset of head and neck squamous cell carcinomas (HNSCC) and anogenital cancers, particularly cervical cancer (CC). The major viral proteins that contribute to tumorigenesis are the E6 and E7 oncoproteins, whose expression is usually enhanced after the integration of viral DNA into the host genome. Recently, an alternative tumorigenesis pathway has been suggested in approximately half of HNSCC and CC cases associated with HPV infection.

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Nanoparticles serving as a multifunctional and multiaddressable dopant to modify the properties of liquid crystalline matrices are developed by combining cobalt ferrite nanocrystals with organic ligands featuring a robust photosensitive unit and a source of chirality from the natural pool. These nanoparticles provide a stable nanocomposite when dispersed in achiral liquid crystals, giving rise to chiral supramolecular structures that can respond to UV-light illumination, and, at the same time, the formed nanocomposite possesses strong magnetic response. We report on a nanocomposite that shows three additional functionalities (chirality and responsiveness to UV light and magnetic field) upon the introduction of a single dopant into achiral liquid crystals.

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Tumor-associated macrophages (TAMs) plentifully infiltrate the tumor microenvironment (TME), but their role in anti-tumor immunity is controversial. Depending on the acquired polarization, they can either support tumor growth or participate in the elimination of neoplastic cells. In this study, we analyzed the TME by RNA-seq and flow cytometry and examined TAMs after ex vivo activation.

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Cluster of differentiation (CD) 80 is mainly expressed in immune cells but can also be found in several types of cancer cells. This molecule may either activate or inhibit immune reactions. Here, we determined the immunosuppressive role of CD80 in the tumor microenvironment by CRISPR/Cas9-mediated deactivation of the corresponding gene in the mouse oncogenic TC-1 cell line.

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Head and neck squamous cell carcinomas (HNSCC) can be induced by smoking or alcohol consumption, but a growing part of cases relate to a persistent high-risk papillomavirus (HPV) infection. Viral etiology has a beneficial impact on the prognosis, which may be explained by a specific immune response. Tumor associated macrophages (TAMs) represent the main immune population of the tumor microenvironment with a controversial influence on the prognosis.

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As metastasis is a major cause of death in cancer patients, new anti-metastatic strategies are needed to improve cancer therapy outcomes. Numerous pathways have been shown to contribute to migration and invasion of malignant tumors. Aspartate β-hydroxylase (ASPH) is a key player in the malignant transformation of solid tumors by enhancing cell proliferation, migration, and invasion.

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Programmed cell death protein 1 (PD-1)/PD-1 ligand 1 (PD-L1) blockade is a promising therapy for various cancer types, but most patients are still resistant. Therefore, a larger number of predictive biomarkers is necessary. In this study, we assessed whether a loss-of-function mutation of the interferon (IFN)-γ receptor 1 (IFNGR1) in tumor cells can interfere with anti-PD-L1 therapy.

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In the majority of human tumors, downregulation of major histocompatibility complex class I (MHC‑I) expression contributes to the escape from the host immune system and resistance to immunotherapy. Relevant animal models are therefore needed to enhance the efficacy of cancer immunotherapy. As loss of β‑2 microglobulin expression results in irreversible downregulation of surface MHC‑I molecules in various human tumors, the β‑2 microglobulin gene (B2m) was deactivated in a mouse oncogenic TC‑1 cell line and a TC‑1/dB2m cell line that was negative for surface MHC‑I expression was derived.

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Liquid crystals (LCs) are among the most prominent materials of the current information age, mainly due to their well-known application in liquid crystal displays (LCDs). Their unique electro-optical properties stem from their ability to form organised structures (mesophases) on the transition from solid state to isotropic liquid. Molecules of LCs in a mesophase still maintain the anisotropy of solid crystals, while simultaneously exhibiting the fluidity of liquids, which gives the system the ability to react immediately to external stimuli such as electric or magnetic fields, light, mechanical stress, pressure and, of course, temperature.

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Monitoring immune responses to solid cancers may be a better prognostic tool than conventional staging criteria, and it can also serve as an important criterion for the selection of individualized therapy. Multiparametric phenotyping by mass cytometry extended possibilities for immunoprofiling. However, careful optimization of each step of such method is necessary for obtaining reliable results.

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Combined immunotherapy constitutes a novel, advanced strategy in cancer treatment. In this study, we investigated immunotherapy in the mouse TC-1/A9 model of human papillomavirus type 16 (HPV16)-associated tumors characterized by major histocompatibility complex class I (MHC-I) downregulation. We found that the induction of a significant anti-tumor response required a combination of DNA vaccination with the administration of an adjuvant, either the synthetic oligodeoxynucleotide ODN1826, carrying immunostimulatory CpG motifs, or α-galactosylceramide (α-GalCer).

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The therapy of different advanced-stage malignancies with monoclonal antibodies blocking programmed cell death protein 1 (PD-1)/PD-1 ligand 1 (PD-L1) signaling has had an impressive long-lasting effect in a portion of patients, but in most cases, this therapy was not successful, or a secondary resistance developed. To enhance its efficacy in treated patients, predictive biomarkers are searched for and various combination treatments are intensively investigated. As the downregulation of major histocompatibility complex (MHC) class I molecules is one of the most frequent mechanisms of tumor escape from the host's immunity, it should be considered in PD-1/PD-L1 checkpoint inhibition.

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As the extent of centrosome abnormalities in chronic myeloid leukemia (CML) correlates with disease stage and karyotype alterations, abnormal expression of genes encoding centrosomal proteins may be an early prognostic marker of disease progression. In the present study, we showed that in comparison with healthy controls, the expression of four centrosomal genes (AURKA, HMMR, PLK1 and ESPL1) in the peripheral blood of CML patients was significantly enhanced at diagnosis and decreased to the basal level in most patients treated with imatinib mesylate for three months. In the remaining patients (17%), this decrease was delayed and was associated with worse overall survival.

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Article Synopsis
  • - Aurora kinase A (AURKA) is a protein linked to cancer progression, and researchers enhanced its use as a vaccine target by adding a helper epitope and mutating its kinase domain to reduce oncogenicity.
  • - In experiments with mice, a DNA vaccine targeting AURKA did not produce antitumor effects alone, but combining it with anti-CD25 treatment (which depletes regulatory T cells) significantly increased immune response to AURKA when given multiple times.
  • - Observations showed that while one anti-CD25 dose alongside DNA vaccination reduced tumor growth, three doses accelerated it, highlighting the complexity of combining therapies, and indicating that blocking the PD-1 receptor is critical for improving tumor growth inhibition when
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The asparaginyl endopeptidase legumain that is overexpressed in M2-polarized tumor-associated macrophages has been identified as a suitable target for elimination of these cells supporting tumor progression. To enhance the efficacy of DNA immunization against legumain, we performed several modifications in this protein that could improve induction of immune responses. First, we mutated the RGD motif into GGD or RGG sequences.

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As cancer stem cells (CSCs) are resistant to chemotherapy, radiotherapy and targeted molecular therapy, immunotherapy of tumors could be aimed at their elimination. Markers specific for CSCs have not been identified to date, but microarray analyses have shown that CSCs and embryonic stem cells use similar transcriptional programs, thus suggesting the production of shared transcription factors. In this study, we developed an experimental DNA vaccine against the transcription factor Sox2 that is important for self-renewal of stem cells and is overexpressed in numerous human cancers.

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The development of cervical cancer is associated with infection by oncogenic human papillomaviruses (HPVs), of which type 16 (HPV16) is the most prevalent in HPV-induced malignant diseases. The viral oncoproteins E6 and E7 are convenient targets for anti-tumor immunization. To adapt the corresponding genes for DNA vaccination, their oncogenicity needs to be reduced and immunogenicity enhanced.

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Transient expression of foreign genes based on plant viral vectors is a suitable system for the production of relevant immunogens that can be used for the development of a new generation of vaccines against a variety of infectious diseases. In the present study the epitope derived from HPV-16 L2 minor capsid protein (amino acids 108-120) was expressed from Potato virus X (PVX)-based vector pGR106 as N- or C-terminal fusion with the PVX coat protein (PVX CP) in transgenic Nicotiana benthamiana plants. The fusion protein L2 108-120-PVX CP was successfully expressed in plants at a level of 170 mg/kg of fresh leaf tissue.

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Treatment with imatinib mesylate and other tyrosine kinase inhibitors (TKI) revolutionized the therapy of chronic myeloid leukemia (CML). However, it alone does not cure this disease. Moreover, some patients develop resistance or adverse effects to this therapy.

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