New synergistic combination therapy approaches with HDAC inhibitor quisinostat, cisplatin or PARP inhibitor talazoparib for urothelial carcinoma.

Urothelial carcinoma (UC) urgently requires new therapeutic options. Histone deacetylases (HDAC) are frequently dysregulated in UC and constitute interesting targets for the development of alternative therapy options. Thus, we investigated the effect of the second generation HDAC inhibitor (HDACi) quisinostat in five UC cell lines (UCC) and two normal control cell lines in comparison to romidepsin, a well characterized HDACi which was previously shown to induce cell death and cell cycle arrest. In UCC, quisinostat led to cell cycle alterations, cell death induction and DNA damage, but was well tolerated by normal cells. Combinations of quisinostat with cisplatin or the PARP inhibitor talazoparib led to decrease in cell viability and significant synergistic effect in five UCCs and platinum-resistant sublines allowing dose reduction. Further analyses in UM-UC-3 and J82 at low dose ratio revealed that the mechanisms included cell cycle disturbance, apoptosis induction and DNA damage. These combinations appeared to be well tolerated in normal cells. In conclusion, our results suggest new promising combination regimes for treatment of UC, also in the cisplatin-resistant setting.

Anticancer efficacy triggered by synergistically modulating the homeostasis of anions and iron: Design, synthesis and biological evaluation of dual-functional squaramide-hydroxamic acid conjugates.

Targeting the homeostasis of anions and iron has emerged as a promising therapeutic approach for the treatment of cancers. However, single-targeted agents often fall short of achieving optimal treatment efficacy. Herein we designed and synthesized a series of novel dual-functional squaramide-hydroxamic acid conjugates that are capable of synergistically modulating the homeostasis of anions and iron. Among them, compound 16 exhibited the most potent antiproliferative activity against a panel of selected cancer cell lines, and strong in vivo anti-tumor efficacy. This compound effectively elevated lysosomal pH through anion transport, and reduced the levels of intracellular iron. Compound 16 could disturb autophagy in A549 cells and trigger robust apoptosis. This compound caused cell cycle arrest at the G1/S phase, altered the mitochondrial function and elevated ROS levels. The present findings clearly demonstrated that synergistic modulation of anion and iron homeostasis has high potentials in the development of promising chemotherapeutic agents with dual action against cancers.

HDAC6 inhibitor promotes reactive oxygen species-meditated clearance of Staphylococcus aureus in macrophage.

Staphylococcus aureus (S. aureus) pneumonia has become an increasingly important public health problem. Recent evidence suggests that epigenetic modifications are critical in the host immune defence against pathogen infection. In this study, we found that S. aureus infection induces the expression of histone deacetylase 6 (HDAC6) in a dose-dependent manner. Furthermore, by using a S. aureus pneumonia mouse model, we showed that the HDAC6 inhibitor, tubastatin A, demonstrates a protective effect in S. aureus pneumonia, decreasing the mortality and destruction of lung architecture, reducing the bacterial burden in the lungs and inhibiting inflammatory responses. Mechanistic studies in primary bone marrow-derived macrophages demonstrated that the HDAC6 inhibitors, tubastatin A and tubacin, reduced the intracellular bacterial load by promoting bacterial clearance rather than regulating phagocytosis. Finally, N-acetyl-L- cysteine, a widely used reactive oxygen species (ROS) scavenger, antagonized ROS production and significantly inhibited tubastatin A-induced S. aureus clearance. These findings demonstrate that HDAC6 inhibitors promote the bactericidal activity of macrophages by inducing ROS, an important host factor for S. aureus clearance and production. Our study identified HDAC6 as a suitable epigenetic modification target for preventing S. aureus infection, and tubastatin A as a useful compound in treating S. aureus pneumonia.

Trichostatin A-modified vaccine provides superior protection against ovarian cancer formation and development.

More attention has been paid to immunotherapy for ovarian cancer and the development of tumor vaccines. We developed a trichostatin A (TSA)-modified tumor vaccine with potent immunomodulating activities that can inhibit the growth of ovarian cancer in rats and stimulate immune cell response in vivo. TSA-treated Nutu-19 cells inactivated by X-ray radiation were used as a tumor vaccine in rat ovarian cancer models. Prophylactic and therapeutic experiments were performed with TSA-modified tumor vaccine in rats. Flow cytometry and ELISpot assays were conducted to assess immune response. Immune cell expression in the spleen and thymus were detected by immunohistochemical staining. GM-CSF, IL-7, IL-17, LIF, LIX, KC, MCP-1, MIP-2, M-CSF, IP-10/CXCL10, MIG/CXCL9, RANTES, IL-4, IFN-γ, and VEGF expressions were detected with Milliplex Map Magnetic Bead Panel immunoassay. TSA vaccination in therapeutic and prophylactic models could effectively stimulate innate immunity and boost the adaptive humoral and cell-mediated immune responses to inhibit the growth and tumorigenesis of ovarian cancer. This vaccine stimulated the thymus into reactivating status and enhanced infiltrating lymphocytes in tumor-bearing rats. The expression of key immunoregulatory factors were upregulated in the vaccine group. The intensities of infiltrating CD4+ and CD8+ T cells and NK cells were significantly increased in the vaccine group compared to the control group (P<0.05). This protection was mainly dependent on the IFN-γ pathway and, to a much lesser extent, by the IL-4 pathway. The tumor cells only irradiated by X-ray as the control group still showed a slight immune effect, indicating that irradiated cells may also cause certain immune antigen exposure, but the efficacy was not as significant as that of the TSA-modified tumor vaccine. Our study revealed the potential application of the TSA-modified tumor vaccine as a novel tumor vaccine against tumor refractoriness and growth. These findings offer a better understanding of the immunomodulatory effects of the vaccine against latent tumorigenesis and progression. This tumor vaccine therapy may increase antigen exposure, synergistically activate the immune system, and ultimately improve remission rates. A vaccine strategy designed to induce effective tumor immune response is being considered for cancer immunotherapy.

Reverse N-Substituted Hydroxamic Acid Derivatives of Fosmidomycin Target a Previously Unknown Subpocket of 1-Deoxy-d-xylulose 5-Phosphate Reductoisomerase (DXR).

Reverse analogs of the phosphonohydroxamic acid antibiotic fosmidomycin are potent inhibitors of the nonmevalonate isoprenoid biosynthesis enzyme 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR, IspC) of Plasmodium falciparum. Some novel analogs with large phenylalkyl substituents at the hydroxamic acid nitrogen exhibit nanomolar PfDXR inhibition and potent in vitro growth inhibition of P. falciparum parasites coupled with good parasite selectivity. X-ray crystallographic studies demonstrated that the N-phenylpropyl substituent of the newly developed lead compound 13e is accommodated in a subpocket within the DXR catalytic domain but does not reach the NADPH binding pocket of the N-terminal domain. As shown for reverse carba and thia analogs, PfDXR selectively binds the S-enantiomer of the new lead compound. In addition, some representatives of the novel inhibitor subclass are nanomolar Escherichia coli DXR inhibitors, whereas the inhibition of Mycobacterium tuberculosis DXR is considerably weaker.

Neutrophil Elastase Degrades Histone Deacetylases and Sirtuin 1 in Primary Human Monocyte Derived Macrophages.

Neutrophil elastase (NE) is taken up by macrophages, retains intracellular protease activity, and induces a pro-inflammatory phenotype. However, the mechanism of NE-induced pro-inflammatory polarization of macrophages is not well understood. We hypothesized that intracellular NE degrades histone deacetylases (HDAC) and Sirtuins, disrupting the balance of lysine acetylation and deacetylation and resulting in nuclear to cytoplasmic translocation of a major alarmin, High Mobility Group Box 1 (HMGB1), a pro-inflammatory response in macrophages. Human blood monocytes were obtained from healthy donors or from subjects with cystic fibrosis (CF) or chronic obstructive pulmonary disease (COPD). Monocytes were differentiated into blood monocyte derived macrophages (BMDMs) in vitro. Human BMDMs were exposed to NE or control vehicle, and the abundance of HDACs and Sirtuins was determined by Western blotting of total cell lysates or nuclear extracts or determined by ELISA. HDAC, Sirtuin, and Histone acetyltransferase (HAT) activities were measured. NE degraded most HDACs and Sirtuin (Sirt)1, resulting in decreased HDAC and sirtuin activities, with minimal change in HAT activity. We then evaluated whether the NE-induced loss of Sirt activity or loss of HDAC activities would alter the cellular localization of HMGB1. NE treatment or treatment with Trichostatin A (TSA), a global HDAC inhibitor, both increased HMGB1 translocation from the nucleus to the cytoplasm, consistent with HMGB1 activation. NE significantly degraded Class I and II HDAC family members and Sirt 1, which shifted BMDMs to a pro-inflammatory phenotype.

Epigenetic Activation of Cytochrome P450 1A2 Sensitizes Hepatocellular Carcinoma Cells to Sorafenib.

Cytochrome P450 1A2 (CYP1A2) is a known tumor suppressor in hepatocellular carcinoma (HCC), but its expression is repressed in HCC and the underlying mechanism is unclear. In this study, we investigated the epigenetic mechanisms of CYP1A2 repression and potential therapeutic implications. In HCC tumor tissues, the methylation rates of CYP1A2 CpG island (CGI) and DNA methyltransferase (DNMT) 3A protein levels were significantly higher, and there was a clear negative correlation between DNMT3A and CYP1A2 protein expression. Knockdown of DNMT3A by siRNA significantly increased CYP1A2 expression in HCC cells. Additionally, treating HCC cells with decitabine (DAC) resulted in a dose-dependent upregulation of CYP1A2 expression by reducing the methylation level of CYP1A2 CGI. Furthermore, we observed a decreased enrichment of H3K27Ac in the promoter region of CYP1A2 in HCC tissues. Treatment with the trichostatin A (TSA) restored CYP1A2 expression in HCC cells by increasing H3K27Ac levels in the CYP1A2 promoter region. Importantly, combination treatment of sorafenib with DAC or TSA resulted in a leftward shift of the dose-response curve, lower IC50 values, and reduced colony numbers in HCC cells. Our findings suggest that hypermethylation of the CGI at the promoter, mediated by the high expression of DNMT3A, and hypoacetylation of H3K27 in the CYP1A2 promoter region, leads to CYP1A2 repression in HCC. Epigenetic drugs DAC and TSA increase HCC cell sensitivity to sorafenib by restoring CYP1A2 expression. Our study provides new insights into the epigenetic regulation of CYP1A2 in HCC and highlights the potential of epigenetic drugs as a therapeutic approach for HCC. SIGNIFICANCE STATEMENT: This study marks the first exploration of the epigenetic mechanisms underlying cytochrome P450 (CYP) 1A2 suppression in hepatocellular carcinoma (HCC). Our findings reveal that heightened DNA methyltransferase expression induces hypermethylation of the CpG island at the promoter, coupled with diminished H3K27Ac levels, resulting in the repression of CYP1A2 in HCC. The use of epigenetic drugs such as decitabine and trichostatin A emerges as a novel therapeutic avenue, demonstrating their potential to restore CYP1A2 expression and enhance sorafenib sensitivity in HCC cells.

In-vitro and in-silico analysis and antitumor studies of novel Cu(II) and V(V) complexes of N-p-Tolylbenzohydroxamic acid.

Copper(L2Cu) and vanadium(L2VOCl) complexes of N-p-tolylbenzohydroxamic acid (LH) ligand have been investigated for DNA binding efficacy by multiple analytical, spectral, and computational techniques. The results revealed that complexes as groove binders as evidenced by UV absorption. Fluorescence studies including displacement assay using classical intercalator ethidium bromide as fluorescent probe also confirmed as groove binders. The viscometric analysis too supports the inferences as strong groove binders for both the complexes. Molecular docking too exposed DNA as a target to the complexes which precisely binds L2Cu, in the minor groove region while L2VOCl in major groove region. Molecular dynamic simulation performed on L2Cu complex revealing the interaction of complex with DNA within 20 ns time. The complex stacked into the nitrogen bases of oligonucleotides and the bonding features were intrinsically preserved for longer simulation times. In-vitro cytotoxicity study was undertaken employing MTT assay against the breast cancer cell line (MCF-7). Potential cytotoxic activities were observed for L2Cu and L2VOCl complexes with IC50 values of showing 71 % and 74 % of inhibition respectively.

GW501516-Mediated Targeting of Tetraspanin 15 Regulates ADAM10-Dependent N-Cadherin Cleavage in Invasive Bladder Cancer Cells.

Bladder cancer aggressiveness is correlated with abnormal N-cadherin transmembrane glycoprotein expression. This protein is cleaved by the metalloprotease ADAM10 and the γ-secretase complex releasing a pro-angiogenic N-terminal fragment (NTF) and a proliferation-activating soluble C-terminal fragment (CTF2). Tetraspanin 15 (Tspan15) is identified as an ADAM10-interacting protein to induce selective N-cadherin cleavage. We first demonstrated, in invasive T24 bladder cancer cells, that N-cadherin was cleaved by ADAM10 generating NTF in the extracellular environment and leaving a membrane-anchored CTF1 fragment and that Tspan15 is required for ADAM10 to induce the selective N-cadherin cleavage. Targeting N-cadherin function in cancer is relevant to preventing tumor progression and metastases. For antitumor molecules to inhibit N-cadherin function, they should be complete and not cleaved. We first showed that the GW501516, an agonist of the nuclear receptor PPARß/δ, decreased Tspan15 and prevented N-cadherin cleavage thus decreasing NTF. Interestingly, the drug did not modify ADAM10 expression, which was important because it could limit side effects since ADAM10 cleaves numerous substrates. By targeting Tspan15 to block ADAM10 activity on N-cadherin, GW501516 could prevent NTF pro-tumoral effects and be a promising molecule to treat bladder cancer. More interestingly, it could optimize the effects of the N-cadherin antagonists those such as ADH-1 that target the N-cadherin ectodomain.

Tubastatin alleviates epidural fibrosis via negatively targeting TGFß/PI3K/Akt pathway.

Epidural fibrosis (EF) is a chronic, progressive and severe disease. Histone deacetylase 6 (HDAC6) regulates biological signals and cell activities by deacetylating lysine residues and participates in TGF-ß-induced epithelial-mesenchymal transition (EMT). Nevertheless, the effect and mechanism of HDAC6 in EF remain unclear. To investigate the effect and mechanism of HDAC6 inhibition on repressing epidural fibrosis. HDAC6 expression and α-smooth muscle actin (α-SMA) in normal human tissue and human EF tissue were assessed by quantitative real-time PCR (qRT-PCR) and western blotting. Human fibroblasts were treated with TGF-ß ± HDAC6 inhibitors (Tubastatin) and fibrotic markers including collagen I, collagen III, α-SMA and fibronectin were assessed using western blotting. Then TGFß1 receptor (TGFß1-R), PI3K and Akt were analyzed using qRT-PCR and western blotting. Rats were undergone laminectomy± Tubastatin (intraperitoneally injection; daily for 7 days) and epidural scar extracellular matrix (ECM) expression was gauged using immunoblots. Increasing HDAC6 expression was associated with α-SMA enrichment. Tubastatin remarkably restrained TGF-ß-induced level of collagen and ECM deposition in human fibroblasts, and the discovery was accompanied by decreased PI3K and Akt phosphorylation. Moreover, Tubastatin also inhibited TGF-ß-mediated HIF-1α and VEGF expression. In the epidural fibrosis model, we found that Tubastatin weakened scar hyperplasia and collagen deposition, and effectively inhibited the process of epidural fibrosis. These results indicated that Tubastatin inhibited HDAC6 expression and decreased TGF-ß/ PI3K/ Akt pathway that promotes collagen and ECM deposition and VEGF release, leading reduction of myofibroblast activation. Hence, Tubastatin ameliorated epidural fibrosis development.

Batimastat Induces Cytotoxic and Cytostatic Effects in In Vitro Models of Hematological Tumors.

The role of metalloproteinases (MMPs) in hematological malignancies, like acute myeloid leukemia (AML), myelodysplastic neoplasms (MDS), and multiple myeloma (MM), is well-documented, and these pathologies remain with poor outcomes despite treatment advancements. In this study, we investigated the effects of batimastat (BB-94), an MMP inhibitor (MMPi), in single-administration and daily administration schemes in AML, MDS, and MM cell lines. We used four hematologic neoplasia cell lines: the HL-60 and NB-4 cells as AML models, the F36-P cells as an MDS model, and the H929 cells as a model of MM. We also tested batimastat toxicity in a normal human lymphocyte cell line (IMC cells). BB-94 decreases cell viability and density in a dose-, time-, administration-scheme-, and cell-line-dependent manner, with the AML cells displaying higher responses. The efficacy in inducing apoptosis and cell cycle arrests is dependent on the cell line (higher effects in AML cells), especially with lower daily doses, which may mitigate treatment toxicity. Furthermore, BB-94 activated apoptosis via caspases and ERK1/2 pathways. These findings highlight batimastat's therapeutic potential in hematological malignancies, with daily dosing emerging as a strategy to minimize adverse effects.

Potentiating Activity of GmhA Inhibitors on Gram-Negative Bacteria.

Inhibition of the biosynthesis of bacterial heptoses opens novel perspectives for antimicrobial therapies. The enzyme GmhA responsible for the first committed biosynthetic step catalyzes the conversion of sedoheptulose 7-phosphate into d-glycero-d-manno-heptose 7-phosphate and harbors a Zn2+ ion in the active site. A series of phosphoryl- and phosphonyl-substituted derivatives featuring a hydroxamate moiety were designed and prepared from suitably protected ribose or hexose derivatives. High-resolution crystal structures of GmhA complexed to two N-formyl hydroxamate inhibitors confirmed the binding interactions to a central Zn2+ ion coordination site. Some of these compounds were found to be nanomolar inhibitors of GmhA. While devoid of HepG2 cytotoxicity and antibacterial activity of their own, they demonstrated in vitro lipopolysaccharide heptosylation inhibition in Enterobacteriaceae as well as the potentiation of erythromycin and rifampicin in a wild-type Escherichia coli strain. These inhibitors pave the way for a novel treatment of Gram-negative infections.

Evaluation of 1,10-phenanthroline-based hydroxamate derivative as dual histone deacetylases/ribonucleotide reductase inhibitor with antitumor activities.

BACKGROUND: Aberrant expression of histone deacetylases (HDACs) and ribonucleotide reductase (RR) enzymes are commonly observed in various cancers. Researchers are focusing on these enzymes in cancer studies with the aim of developing effective chemotherapeutic drugs for cancer treatment. Targeting both HDAC and RR simultaneously with a dual HDAC/RR inhibitor has exhibited enhanced effectiveness compared to monotherapy in cancer treatment, making it a promising strategy. OBJECTIVES: The objective of the study is to synthesize and assess the anti-cancer properties of a 1,10-phenanthroline-based hydroxamate derivative, characterizing it as a novel dual HDAC/RR inhibitor. METHODS: The N1-hydroxy-N8-(1,10-phenanthrolin-5-yl)octanediamide (PA), a 1,10-phenanthroline-based hydroxamate derivative, was synthesized and structurally characterized. The compound was subjected to in vitro assessments of its anti-cancer, HDAC, and RR inhibitory activities. In silico docking and molecular dynamics simulations were further studied to explore its interactions with HDACs and RRM2. RESULTS: The structurally confirmed PA exhibited antiproliferative activity in SiHa cells with an IC50 of 16.43 µM. It displayed potent inhibitory activity against HDAC and RR with IC50 values of 10.80 µM and 9.34 µM, respectively. Co-inhibition of HDAC and RR resulted in apoptosis-induced cell death in SiHa cells, mediated by the accumulation of reactive oxygen species (ROS). In silico docking studies demonstrated that PA can effectively bind to the active sites of HDAC isoforms and RRM2. Furthermore, PA demonstrated a more favorable interaction with HDAC7, displaying a docking score of -9.633 kcal/mol, as compared to the standard HDAC inhibitor suberoylanilide hydroxamic acid (SAHA), which exhibited a docking score of -8.244 kcal/mol against HDAC7. CONCLUSION: The present study emphasizes the prospect of designing a potential 1,10-phenanthroline hydroxamic acid derivative as a novel dual HDAC and RR-inhibiting anti-cancer molecule.

CAMSAP3-mediated regulation of HMGB1 acetylation and subcellular localization in lung cancer cells: Implications for cell death modulation.

BACKGROUND: Deregulation of cell death is a common characteristic of cancer, and resistance to this process often occurs in lung cancer. Understanding the molecular mechanisms underlying an aberrant cell death is important. Recent studies have emphasized the involvement of calmodulin-regulated spectrin-associated protein 3 (CAMSAP3) in lung cancer aggressiveness, its influence on cell death regulation remains largely unexplored. METHODS: CAMSAP3 was knockout in lung cancer cells using CRISPR-Cas9 system. Cell death and autophagy were evaluated using MTT and autophagic detection assays. Protein interactions were performed by proteomic analysis and immunoprecipitation. Protein expressions and their cytoplasmic localization were analyzed through immunoblotting and immunofluorescence techniques. RESULTS: This study reveals a significant correlation between low CAMSAP3 expression and poor overall survival rates in lung cancer patients. Proteomic analysis identified high mobility group box 1 (HMGB1) as a candidate interacting protein involved in the regulation of cell death. Treatment with trichostatin A (TSA), an inhibitor of histone deacetylases (HDACs) resulted in increased HMGB1 acetylation and its translocation to the cytoplasm and secretion, thereby inducing autophagic cell death. However, this process was diminished in CAMSAP3 knockout lung cancer cells. Mechanistically, immunoprecipitation indicated an interaction between CAMSAP3 and HMGB1, particularly with its acetylated form, in which this complex was elevated in the presence of TSA. CONCLUSIONS: CAMSAP3 is prerequisite for TSA-mediated autophagic cell death by interacting with cytoplasmic acetylated HMGB1 and enhancing its release. SIGNIFICANT: This finding provides molecular insights into the role of CAMSAP3 in regulating cell death, highlighting its potential as a therapeutic target for lung cancer treatment.

The Discovery of New Inhibitors of Insulin-Regulated Aminopeptidase by a High-Throughput Screening of 400,000 Drug-like Compounds.

With the ambition to identify novel chemical starting points that can be further optimized into small drug-like inhibitors of insulin-regulated aminopeptidase (IRAP) and serve as potential future cognitive enhancers in the clinic, we conducted an ultra-high-throughput screening campaign of a chemically diverse compound library of approximately 400,000 drug-like small molecules. Three biochemical and one biophysical assays were developed to enable large-scale screening and hit triaging. The screening funnel, designed to be compatible with high-density microplates, was established with two enzyme inhibition assays employing either fluorescent or absorbance readouts. As IRAP is a zinc-dependent enzyme, the remaining active compounds were further evaluated in the primary assay, albeit with the addition of zinc ions. Rescreening with zinc confirmed the inhibitory activity for most compounds, emphasizing a zinc-independent mechanism of action. Additionally, target engagement was confirmed using a complementary biophysical thermal shift assay where compounds causing positive/negative thermal shifts were considered genuine binders. Triaging based on biochemical activity, target engagement, and drug-likeness resulted in the selection of 50 qualified hits, of which the IC50 of 32 compounds was below 3.5 µM. Despite hydroxamic acid dominance, diverse chemotypes with biochemical activity and target engagement were discovered, including non-hydroxamic acid compounds. The most potent compound (QHL1) was resynthesized with a confirmed inhibitory IC50 of 320 nM. Amongst these compounds, 20 new compound structure classes were identified, providing many new starting points for the development of unique IRAP inhibitors. Detailed characterization and optimization of lead compounds, considering both hydroxamic acids and other diverse structures, are in progress for further exploration.

Synergizing structure and function: Cinnamoyl hydroxamic acids as potent urease inhibitors.

The current investigation encompasses the structural planning, synthesis, and evaluation of the urease inhibitory activity of a series of molecular hybrids of hydroxamic acids and Michael acceptors, delineated from the structure of cinnamic acids. The synthesized compounds exhibited potent urease inhibitory effects, with IC50 values ranging from 3.8 to 12.8 µM. Kinetic experiments unveiled that the majority of the synthesized hybrids display characteristics of mixed inhibitors. Generally, derivatives containing electron-withdrawing groups on the aromatic ring demonstrate heightened activity, indicating that the increased electrophilicity of the beta carbon in the Michael Acceptor moiety positively influences the antiureolytic properties of this compounds class. Biophysical and theoretical investigations further corroborated the findings obtained from kinetic assays. These studies suggest that the hydroxamic acid core interacts with the urease active site, while the Michael acceptor moiety binds to one or more allosteric sites adjacent to the active site.

ITF2357 regulates NF-κB signaling pathway to protect barrier integrity in retinal pigment epithelial cells.

The robust integrity of the retinal pigment epithelium (RPE), which contributes to the outer brain retina barrier (oBRB), is compromised in several retinal degenerative and vascular disorders, including diabetic macular edema (DME). This study evaluates the role of a new generation of histone deacetylase inhibitor (HDACi), ITF2357, in regulating outer blood-retinal barrier function and investigates the underlying mechanism of action in inhibiting TNFα-induced damage to RPE integrity. Using the immortalized RPE cell line (ARPE-19), ITF2357 was found to be non-toxic between 50 nM and 5 µM concentrations. When applied as a pre-treatment in conjunction with an inflammatory cytokine, TNFα, the HDACi was safe and effective in preventing epithelial permeability by fortifying tight junction (ZO-1, -2, -3, occludin, claudin-1, -2, -3, -5, -19) and adherens junction (E-cadherin, Nectin-1) protein expression post-TNFα stress. Mechanistically, ITF2357 depicted a late action at 24 h via attenuating IKK, IκBα, and p65 phosphorylation and ameliorated the expression of IL-1ß, IL-6, and MCP-1. Also, ITF2357 delayed IκBα synthesis and turnover. The use of Bay 11-7082 and MG132 further uncovered a possible role for ITF2357 in non-canonical NF-κB activation. Overall, this study revealed the protection effects of ITF2357 by regulating the turnover of tight and adherens junction proteins and modulating NF-κB signaling pathway in the presence of an inflammatory stressor, making it a potential therapeutic application for retinal vascular diseases such as DME with compromised outer blood-retinal barrier.

Hippocampal HDAC6 promotes POCD by regulating NLRP3-induced microglia pyroptosis via HSP90/HSP70 in aged mice.

BACKGROUND: Postoperative Cognitive Dysfunction (POCD) has attracted increased attention, but its precise mechanism remains to be explored. This study aimed to figure out whether HDAC6 could regulate NLRP3-induced pyroptosis by modulating the functions of HSP70 and HSP90 in microglia to participate in postoperative cognitive dysfunction in aged mice. METHODS: Animal models of postoperative cognitive dysfunction in aged mice were established by splenectomy under sevoflurane anesthesia. Morris water maze was used to examine the cognitive function and motor ability. Sixteen-months-old C57BL/6 male mice were randomly divided into six groups: control group (C group), sham surgery group (SA group), splenectomy group (S group), splenectomy + HDAC6 inhibitor ACY-1215 group (ACY group), splenectomy + HDAC6 inhibitor ACY-1215 + HSP70 inhibitor Apoptozole group (AP group), splenectomy + solvent control group (SC group). The serum and hippocampus of mice were taken after mice were executed. The protein levels of HDAC6, HSP90, HSP70, NLRP3, GSDMD-N, cleaved-Caspase-1 (P20), IL-1ß were detected by western blotting. Serum IL-1ß, IL-6 and S100ß were measured using ELISA assay, and cell localization of HDAC6 was detected by immunofluorescence. In vitro experiments, BV2 cells were used to validate whether this mechanism worked in microglia. The protein levels of HDAC6, HSP90, HSP70, NLRP3, GSDMD-N, P20, IL-1ß were detected by western blotting and the content of IL-1ß in the supernatant was measured using ELISA assay. The degree of acetylation of HSP90, the interaction of HSP70, HSP90 and NLRP3 were analyzed by coimmunoprecipitation assay. RESULTS: Splenectomy under sevoflurane anesthesia in aged mice could prolong the escape latency, reduce the number of crossing platforms, increase the expression of HDAC6 and activate the NLRP3 inflammasome to induce pyroptosis in hippocampus microglia. Using ACY-1215 could reduce the activation of NLRP3 inflammasome, the pyroptosis of microglia and the degree of spatial memory impairment. Apoptozole could inhibit the binding of HSP70 to NLRP3, reduce the degradation of NLRP3 and reverse the protective effect of HDAC6 inhibitors. The results acquired in vitro experiments closely resembled those in vivo, LPS stimulation led to the pyroptosis of BV2 microglia cells and the release of IL-1ß due to the activation of the NLRP3 inflammasome, ACY-1215 showed the anti-inflammatory effect and Apoptozole exerted the opposite effect. CONCLUSIONS: Our findings suggest that hippocampal HDAC6 promotes POCD by regulating NLRP3-induced microglia pyroptosis via HSP90/HSP70 in aged mice.

Phase II trial of domatinostat (4SC-202) in combination with avelumab in patients with previously treated advanced mismatch repair proficient oesophagogastric and colorectal adenocarcinoma: EMERGE.

BACKGROUND: Most oesophagogastric adenocarcinomas (OGAs) and colorectal cancers (CRCs) are mismatch repair proficient (MMRp), responding poorly to immune checkpoint inhibition. We evaluated the safety and efficacy of domatinostat (histone deacetylase inhibitor) plus avelumab (anti-PD-L1 antibody) in patients with previously treated inoperable, advanced/metastatic MMRp OGA and CRC. PATIENTS AND METHODS: Eligible patients were evaluated in a multicentre, open-label dose escalation/dose expansion phase II trial. In the escalation phase, patients received escalating doses of domatinostat [100 mg once daily (OD), 200 mg OD, 200 mg twice daily (BD)] orally for 14 days followed by continuous dosing plus avelumab 10 mg/kg administered intravenously 2-weekly (2qw) to determine the recommended phase II dose (RP2D). The trial expansion phase evaluated the best objective response rate (ORR) during 6 months by RECIST version 1.1 using a Simon two-stage optimal design with 2/9 and 1/10 responses required to proceed to stage 2 in the OGA and CRC cohorts, respectively. RESULTS: Patients (n = 40) were registered between February 2019 and October 2021. Patients in the dose escalation phase (n = 12) were evaluated to confirm the RP2D of domatinostat 200 mg BD plus avelumab 10 mg/kg. No dose-limiting toxicities were observed. Twenty-one patients were treated at the RP2D, 19 (9 OGA and 10 CRC) were assessable for the best ORR; 2 patients with CRC did not receive combination treatment and were not assessable for the primary endpoint analysis. Six patients were evaluated in the dose escalation and expansion phases. In the OGA cohort, the best ORR was 22.2% (95% one-sided confidence interval lower bound 4.1) and the median duration of disease control was 11.3 months (range 9.9-12.7 months). No responses were observed in the CRC cohort. No treatment-related grade 3-4 adverse events were reported at the RP2D. CONCLUSIONS: Responses in the OGA cohort met the criteria to expand to stage 2 of recruitment with an acceptable safety profile. There was insufficient signal in the CRC cohort to progress to stage 2. TRIAL REGISTRATION: NCT03812796 (registered 23rd January 2019).

The Utility of Spectroscopic MRI in Stereotactic Biopsy and Radiotherapy Guidance in Newly Diagnosed Glioblastoma.

Current diagnostic and therapeutic approaches for gliomas have limitations hindering survival outcomes. We propose spectroscopic magnetic resonance imaging as an adjunct to standard MRI to bridge these gaps. Spectroscopic MRI is a volumetric MRI technique capable of identifying tumor infiltration based on its elevated choline (Cho) and decreased N-acetylaspartate (NAA). We present the clinical translatability of spectroscopic imaging with a Cho/NAA ≥ 5x threshold for delineating a biopsy target in a patient diagnosed with non-enhancing glioma. Then, we describe the relationship between the undertreated tumor detected with metabolite imaging and overall survival (OS) from a pilot study of newly diagnosed GBM patients treated with belinostat and chemoradiation. Each cohort (control and belinostat) were split into subgroups using the median difference between pre-radiotherapy Cho/NAA ≥ 2x and the treated T1-weighted contrast-enhanced (T1w-CE) volume. We used the Kaplan-Meier estimator to calculate median OS for each subgroup. The median OS was 14.4 months when the difference between Cho/NAA ≥ 2x and T1w-CE volumes was higher than the median compared with 34.3 months when this difference was lower than the median. The T1w-CE volumes were similar in both subgroups. We find that patients who had lower volumes of undertreated tumors detected via spectroscopy had better survival outcomes.