Transcription control by the ENL YEATS domain in acute leukaemia

Recurrent chromosomal translocations producing a chimaeric MLL oncogene give rise to a highly aggressive acute leukaemia associated with poor clinical outcome. The preferential involvement of chromatin-associated factors as MLL fusion partners belies a dependency on transcription control. Despite recent progress made in targeting chromatin regulators in cancer, available therapies for this well-characterized disease remain inadequate, prompting the need to identify new targets for therapeutic intervention. Here, using unbiased CRISPR-Cas9 technology to perform a genome-scale loss-of-function screen in an MLL-AF4-positive acute leukaemia cell line, we identify ENL as an unrecognized gene that is specifically required for proliferation in vitro and in vivo. To explain the mechanistic role of ENL in leukaemia pathogenesis and dynamic transcription control, a chemical genetic strategy was developed to achieve targeted protein degradation. Acute loss of ENL suppressed the initiation and elongation of RNA polymerase II at active genes genome-wide, with pronounced effects at genes featuring a disproportionate ENL load. Notably, an intact YEATS chromatin-reader domain was essential for ENL-dependent leukaemic growth. Overall, these findings identify a dependency factor in acute leukaemia and suggest a mechanistic rationale for disrupting the YEATS domain in disease.K. LubinE. Wood

Discovery of small molecules targeting tumor immune response and tumor cell metastasis

I. Targeted protein degradation of TIP60 to regulate Treg cell activity in lung cancer Regulatory T (Treg) cells are significant contributors to immune system suppression. Foxp3 is the key transcriptional regulator of Treg cells, responsible for their development and function. Foxp3 is a target of acetylation by lysine acetyltransferases (KATs), such as TIP60 and P300. The acetylation of Foxp3 regulates Treg cells activity, leading to a suppression of immune responses. TIP60 is the major protein that has been shown to regulate the Treg cell level by interacting with Foxp3. Therefore, targeting TIP60 in a selective manner is significant for the regulation of immune system activity. We designed a library of TIP60 degraders to recruit the Cereblon (CRBN) E3 ubiquitin ligase and promote ligand-induced dimerization of TIP60 and CRBN in cells to degrade TIP60 by the proteasome. By varying linker composition and length, we were able to assess conditions that allow for effective degradation of TIP60 in vitro and in vivo. II. Synthesis of small molecule inhibitors for Gαi-GIV protein-protein interaction to target cell migration in breast cancer. G-protein coupled receptors (GPCRs) are the largest, most diverse group of membrane receptors in eukaryotes, with a crucial role in cell function and activity. Heterotrimeric G proteins are highly utilized signaling nodes and achieving and controlling their activation have been of interest for decades. GIV, a metastasis-related protein expressed in highly invasive cancer cells, binds, and activates Gα, resulting in the dissociation of Gβγ which leads to cell migration in cancer. Therefore, we designed small molecule modulators to target the Gαi-GIV interaction. NMR binding studies, along with computational modeling enabled us to synthesize a library of fluorene-sulfonamide analogues. In vivo studies after treating the MDA-MB-231 bearing mice with the most potent analogue from the library showed a decrease in tumor cell migration.2023-03-30T00:00:00

A Key Major Guideline for Engineering Bioactive Multicomponent Nanofunctionalization for Biomedicine and Other Applications: Fundamental Models Confirmed by Both Direct and Indirect Evidence

This paper deals with the engineering multicomponent nanofunctionalization process considering fundamental physicochemical features of nanostructures such as surface energy, chemical bonds, and electrostatic interactions. It is pursued by modeling the surface nanopatterning and evaluating the proposed technique and the models. To this end, the effects of surface modifications of nanoclay on surface interactions, orientations, and final features of TiO2/Mt nanocolloidal textiles functionalization have been investigated. Various properties of cross-linkable polysiloxanes (XPs) treated samples as well as untreated samples with XPs have been compared to one another. The complete series of samples have been examined in terms of bioactivity and some physical properties, given to provide indirect evidence on the surface nanopatterning. The results disclosed a key role of the selected factors on the final features of treated surfaces. The effects have been thoroughly explained and modeled according to the fundamental physicochemical features. The developed models and associated hypotheses interestingly demonstrated a full agreement with all measured properties and were appreciably confirmed by FESEM evidence (direct evidence). Accordingly, a guideline has been developed to facilitate engineering and optimizing the pre-, main, and post-multicomponent nanofunctionalization procedures in terms of fundamental features of nanostructures and substrates for biomedical applications and other approaches

The effect of CTB on P53 protein acetylation and consequence apoptosis on MCF-7 and MRC-5 cell lines

Background: P300 is a member of the mammalian histone acetyl transferase (HAT) family, an enzyme that acetylates histones and several non-histone proteins including P53 (the most important tumor suppressor gene) during stress, which plays an important role in the apoptosis of tumor cells. Hereby, this study describes the potency of CTB (Cholera Toxin B subunit) as a P300 activator to induce apoptosis in a breast cancer cell line (MCF-7) and a lung fibroblast cell line (MRC-5) as a non-tumorigenic control sample. Materials and Methods: MCF-7 and MRC-5 were cultured in RPMI-1640 and treated with or without CTB at a concentration of 85.43 μmol/L, based on half-maximal inhibitory concentration (IC50) index at different times (24, 48 and 72 h). The percentage of apoptotic cells were measured by flow cytometry. Real-time quantitative RT-PCR was performed to estimate the mRNA expression of P300 in MCF-7 and MRC-5 with CTB at different times. ELISA and Bradford protein techniques were used to detect levels of total and acetylated P53 protein generated in MCF-7 and MRC-5. Results: Our findings indicated that CTB could effectively induce apoptosis in MCF-7 significantly higher than MRC-5. We showed that expression of P300 was up-regulated by increasing time of CTB treatment in MCF-7 but not in MRC-5 and the acetylated and total P53 protein levels were increased more in MCF-7 cells than MRC-5. Conclusion: CTB could induce acetylation of P53 protein through increasing expression of P300 and consequently induce the significant cell death in MCF-7 but it could be well tolerated in MRC-5. Therefore, CTB could be used as an anti-cancer agent

Thrombotic thrombocytopenic purpura following ChAdOx1 nCov-19 vaccination: A case report

Vaccine-associated thrombotic thrombocytopenic purpura (TTP) is a rare type of acquired TTP recently reported after COVID-19 vaccination. Merely four cases are ascribed to the ChAdOx1 nCoV-19 vaccine in the medical literature till the preparation of this study. In this case report, we describe a 43-year-old man who developed symptoms of TTP four days after receiving the second dose of the ChAdOx1 nCoV-19 vaccine. Peripheral blood smear demonstrated multiple schistocytes. Given a high plasmic score, he received plasma exchange, corticosteroids, and rituximab, and later, low ADAMTS 13 activity and high-titer ADAMTS inhibition antibody confirmed the diagnosis of COVID-19 vaccine-associated TTP. COVID-19 vaccine-associated TTP is an infrequent consequence of SARS-CoV-2 vaccination but with a substantial mortality rate which must be considered as one of the crucial differential diagnoses of post-COVID-19 vaccine thrombocytopenia besides vaccine-induced immune thrombotic thrombocytopenia and Immune thrombocytopenic purpura

Transcription control by the ENL YEATS domain in acute leukemia

Recurrent chromosomal translocations involving the mixed lineage leukemia gene (MLL) give rise to a highly aggressive acute leukemia associated with poor clinical outcome1. The preferential involvement of chromatin-associated factors in MLL rearrangement belies a dependency on transcription control2. Despite recent progress made in targeting chromatin regulators in cancer3, available therapies for this well-characterized disease remain inadequate, prompting the present effort to qualify new targets for therapeutic intervention. Using unbiased, emerging CRISPR-Cas9 technology to perform a genome-scale loss-of-function screen in MLL-AF4-positive acute leukemia, we identified ENL (eleven-nineteen leukemia) as an unrecognized dependency particularly indispensable for proliferation in vitro and in vivo. To explain the mechanistic role for ENL in leukemia pathogenesis and dynamic transcription control, we pursued a chemical genetic strategy utilizing targeted protein degradation. Acute ENL loss suppresses transcription initiation and elongation genome-wide, with pronounced effects at genes featuring disproportionate ENL load. Importantly, ENL-dependent leukemic growth was contingent upon an intact YEATS chromatin reader domain. These findings reveal a novel dependency in acute leukemia and a first mechanistic rational for disrupting the YEATS domain in disease