Alexey Petukhov

Proapoptotic modification of substituted isoindolinones as MDM2-p53 inhibitors

A series of novel amino acid ester derivatives of 2,3-substituted isoindolinones was synthesized and evaluated for p53-mediated apoptotic activity. The rationale for augmentation of the target activity of 2,3-substituted isoindolinones was based on the introduction of new fragments in the structure of the inhibitor that would provide additional binding sites in the hydrophobic cavity of MDM2. To select for the anticipated modifications we employed molecular docking. Synthesized molecules were evaluated for their ability to induce apoptosis in two cancer cell lines and their derivatives with different status of p53 (colorectal HCT116 and osteosarcoma U2OS cells) by Annexin V staining. The target activity was estimated using high-content imaging system Operetta. Valine and phenylglycine ester derivatives were identified as potentially active MDM2-p53 inhibitors.

One-carbon metabolism and nucleotide biosynthesis as attractive targets for anticancer therapy

Cancer-related metabolism has recently emerged as one of the “hallmarks of cancer”. It has several important features, including altered metabolism of glucose and glutamine. Importantly, altered cancer metabolism connects different biochemical pathways into the one fine-tuned metabolic network, which stimulates high proliferation rates and plasticity to malignant cells. Among the keystones of cancer metabolism are one-carbon metabolism and nucleotide biosynthesis, which provide building blocks to anabolic reactions. Accordingly, the importance of these metabolic pathways for anticancer therapy has well been documented by more than fifty years of clinical use of specific metabolic inhibitors – methotrexate and nucleotides analogs. In this review we discuss one-carbon metabolism and nucleotide biosynthesis as common and specific features of many, if not all, tumors. The key enzymes involved in these pathways also represent promising anti-cancer therapeutic targets. We review different aspects of these metabolic pathways including their biochemistry, compartmentalization and expression of the key enzymes and their regulation at different levels. We also discuss the effects of known inhibitors of these pathways as well as the recent data on other enzymes of the same pathways as perspective pharmacological targets.

Spherical actions on flag varieties

For every finite-dimensional vector space V and every V-flag variety X we list all connected reductive subgroups in GL(V acting spherically on X. Bibliography: 28 titles.

Tumor suppressor p63 regulates Pirh2 ubiquitin ligase expression

Tumor suppressor protein p63 is a transcription factor of the p53 protein family. It is known that the proteins of this family, namely, p53, p63, and p73, perform a number of common tumor suppressor functions related to cell cycle regulation, apoptosis, and malignant transformation of cells, in addition to specific functions in the development of tissues and organs. All the proteins of the p53 family are regulated at post-translational level due to ubiquitination by E3 ligases and subsequent proteasomal degradation. The expression of the majority of E3 ubiquitin ligases, which modify the proteins of the p53 family, is regulated by the same proteins, thus forming negative feedback with them. In the present study, we first showed that the expression of the PIRH2 (RCHY1) gene, the product of which ubiquitinates all three members of the p53 family, is also regulated by p63. Regulation of the PIRH2 expression occurs at the transcription level by only fulllength TAp63 isoform, but not ΔNp63 isoform, which lacks a transactivation domain.

VEGFR2-specific FnCAR effectively redirects the cytotoxic activity of T cells and YT NK cells

T and NK cells armed with chimeric antigen receptors (CAR) are promising tools for the specific elimination of cancer cells. In most CAR designs implemented to date, the recognition of target cells is mediated by single-chain variable fragments (scFvs) derived from murine monoclonal antibodies. This format, however, has a number of limitations, including its relatively large size and potential immunogenicity in humans. In this study, we explored the feasibility of using human fibronectin type III domains (Fn3) as the antigen recognition domain in CARs. Human Fn3 domains have lower predicted immunogenicity compared to mouse-derived sequences, and a reduced molecular weight compared to scFvs. We created a functional CAR using a VEGFR2-specific Fn3 module replacing the conventional scFv. The resulting FnCAR specifically potentiates the cytotoxic activity of human T cells and YT NK cells in the presence of VEGFR2-positive targets. These findings demonstrate that Fn3 domains can be used in CARs for antigen recognition.

Specific Drug Delivery to Cancer Cells with Double-Imprinted Nanoparticles against Epidermal Growth Factor Receptor

Epidermal growth factor receptor (EGFR), a tyrosine kinase receptor, is over-expressed in many tumors, including almost half of triple-negative breast cancers. The latter belong to a very-aggressive and drug-resistant form of malignancy. Although humanized anti-EGFR antibodies can work efficiently against these cancers both as monotherapy and in combination with genotoxic drugs, instability and high production costs are some of their known drawbacks in clinical use. In addition, the development of antibodies to target membrane proteins is a very challenging task. Accordingly, the main focus of the present work is the design of supramolecular agents for the targeting of membrane proteins in cancer cells and, hence, more-specific drug delivery. These were produced using a novel double-imprinting approach based on the solid-phase method for preparation of molecularly imprinted polymer nanoparticles (nanoMIPs), which were loaded with doxorubicin and targeted toward a linear epitope of EGFR. Additionally, upon binding, doxorubicin-loaded anti-EGFR nanoMIPs elicited cytotoxicity and apoptosis only in those cells that over-expressed EGFR. Thus, this approach can provide a plausible alternative to conventional antibodies and sets up a new paradigm for the therapeutic application of this class of materials against clinically relevant targets. Furthermore, nanoMIPs can promote the development of cell imaging tools against difficult targets such as membrane proteins.

Evaluation of Immunosuppressive Surface Molecules, Essential for Resistance to CAR T-Cells

S300 lymphocytosis. Immunomagnetic selection of lymphocytes in this group (n 33) showed that the clonal T-cells were CD8+ and CD57+, except two patients with rheumatoid arthritis who had clonal expansion of CD4+ lymphocytes. No clonal Vb-Jb-TCRB rearrangements were revealed in control group, only Db-Jb-TCRB and TCRG. Given the high detectability of monoclonal rearrangements of V b -J b -TCRB(96.7%) in patients with ab -T-LGL, this marker had the greatest (100%) specificity and accuracy (99.2%) for T-cell clonality detection. Also, good specificity and accuracy was achieved when monoclonality was detected in TCRG and TCRB loci simultaneously (100%; 91.2%). Conclusions: The presence of clonal products is common for CD8+CD57+ cells in HI and patients with reactive conditions may not associate with any malignancy. Patients with T-LGL leukemia may have similar T-cell clonality profiles with HI, RD and reactive LGL proliferation. Therefore, interpretation of T-cell clonality should be conducted with caution.

The biological basis and clinical symptoms of CAR-T therapy-associated toxicites

Currently, immunotherapy is attracting a lot of attention and may potentially become a leading approach in the treatment of cancer. One emerging therapeutic, the chimeric-antigen receptor T-cell adoptive immunotherapy (CAR-T) is showing remarkable efficacy in the treatment of several B-cell malignancies. The popularity of CAR-T has been founded on two CAR T-cell products recently approved by FDA (during 2017) in the treatment of relapsed/refractory B-cell acute lymphoblastic leukemia and B-cell lymphoma. However, their toxicities observed in clinical trials were extremely significant and in some cases even fatal with no approved algorithms for toxicity prediction being available to date. A deeper understanding of the biological basis of such complications is the key to prompt and comprehensive clinical management. Here we review the wide spectrum of effects associated with CAR T cell therapy with a major focus on the pathogenesis of cytokine release syndrome and neurotoxicity as the most common, potentially life-threatening effects of this treatment. We discuss the basis of clinical management and the existing models that predict the severity of toxicity, as well as the key factors that modulate this event. Finally, we will summarize the literature detailing universal allogenic CAR T-cells and their toxicity profile.

Novel isatin-derived molecules activate p53 via interference with Mdm2 to promote apoptosis

ABSTRACT The p53 protein is a key tumor suppressor in mammals. In response to various forms of genotoxic stress p53 stimulates expression of genes whose products induce cell cycle arrest and/or apoptosis. An E3-ubiquitin ligase, Mdm2 (mouse-double-minute 2) and its human ortholog Hdm2, physically interact with the amino-terminus of p53 to mediate its ubiquitin-mediated degradation via the proteasome. Thus, pharmacological inhibition of the p53-Mdm2 interaction leads to overall stabilization of p53 and stimulation of its anti-tumorigenic activity. In this study we characterize the biological effects of a novel class of non-genotoxic isatin Schiff and Mannich base derivatives (ISMBDs) that stabilize p53 on the protein level. The likely mechanism behind their positive effect on p53 is mediated via the competitive interaction with Mdm2. Importantly, unlike Nutlin, these compounds selectively promoted p53-mediated cell death. These novel pharmacological activators of p53 can serve as valuable molecular tools for probing p53-positive tumors and set up the stage for development of new anti-cancer drugs.

Non-Covalent Conjugation of Antibodies and Lentiviruses to Nanoparticles as a Potential Tool for Gene Therapy

S394 treatment received, information on the diagnosis/treatment received abroad. Diagnosis delay was defined as the time between the patient’s first symptom recognition to a diagnosis of cancer. Patients: We reviewed and analyzed the charts of the patients’ 18 years old with hematologic malignancies diagnosed and treated at the Clinic of Chemotherapy of Muratsan Hospital Complex of Yerevan State Medical University between 2008 and 2012. Results: During mentioned period of time 33 children with hematologic malignancies were diagnosed and treated at our clinic, from which 20 (61%) were patients with acute lymphoblastic leukemia, 4 (12%) patients with Hodgkin lymphoma and 9 (27%) with Non-Hodgkin lymphoma. From 33 patients information on immunophenotyping was available for 30 (91%), from which only 13 (43%) had the immuopheotyping performed at diagnosis. 14 (42%) patients received part of diagnosis and/or treatment abroad. The most frequent diagnostic/treatment procedure was bone marrow transplantation, otherwise none available in Armenia. 27 (81%) patients had information on diagnosis delay. The median time of diagnosis delay for the group was 42 days (range [1346 days]). The longest delay was reported in Hodgkin lymphoma cases. Conclusions: This single-institution report shows significant therapeutic and diagnostic limitations, as well as diagnosis delay for pediatric hematologic malignancies in Armenia. Larger studies are needed to further explore the contributing factors.