Calcium regulates HCC proliferation as well as EGFR recycling/degradation and could be a new therapeutic target in HCC

Calcium is the most abundant element in the human body. Its role is essential in physiological and biochemical processes such as signal transduction from outside to inside the cell between the cells of an organ, as well as the release of neurotransmitters from neurons, muscle contraction, fertilization, bone building, and blood clotting. As a result, intra- and extracellular calcium levels are tightly regulated by the body. The liver is the most specialized organ of the body, as its functions, carried out by hepatocytes, are strongly governed by calcium ions. In this work, we analyze the role of calcium in human hepatoma (HCC) cell lines harboring a wild type form of the Epidermal Growth Factor Receptor (EGFR), particularly its role in proliferation and in EGFR downmodulation. Our results highlight that calcium is involved in the proliferative capability of HCC cells, as its subtraction is responsible for EGFR degradation by proteasome machinery and, as a consequence, for EGFR intracellular signaling downregulation. However, calcium-regulated EGFR signaling is cell line-dependent. In cells responding weakly to the epidermal growth factor (EGF), calcium seems to have an opposite effect on EGFR internalization/degradation mechanisms. These results suggest that besides EGFR, calcium could be a new therapeutic target in HCC

Identification of Placenta Growth Factor Determinants for Binding and Activation of Flt-1 Receptor

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Natural iminosugar (+)-lentiginosine inhibits ATPase and chaperone activity of Hsp90

Heat shock protein 90 (Hsp90) is a significant target in the development of rational cancer therapy due to its role at the crossroads of multiple signaling pathways associated with cell proliferation and cell viability. The relevance of Hsp90 as a therapeutic target for numerous diseases states has prompted the identification and optimization of novel Hsp90 inhibitors as an emerging therapeutic strategy. We performed a screening aimed to identify novel Hsp90 inhibitors among several natural compounds and we focused on the iminosugar (+)-lentiginosine, a natural amyloglucosidases inhibitor, for its peculiar bioactivity profile. Characterization of Hsp90 inhibition was performed using a panel of chemical and biological approaches, including limited proteolysis, biochemical and cellular assays. Our result suggested that the middle domain of Hsp90, as opposed to its ATP-binding pocket, is a promising binding site for new classes of Hsp90 inhibitors with multitarget anti-cancer potentia

the urokinase receptor derived peptide uparant recovers dysfunctional electroretinogram and blood retinal barrier leakage in a rat model of diabetes

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Investigation of the Complexes Formed between PARP1 Inhibitors and PARP1 G-Quadruplex at the Gene Promoter Region

DNA repair inhibitors are one of the latest additions to cancer chemotherapy. In general, chemotherapy produces DNA damage but tumoral cells may become resistant if enzymes involved in DNA repair are overexpressed and are able to reverse DNA damage. One of the most successful drugs based on modulating DNA repair are the poly(ADP-ribose) polymerase 1 (PARP1) inhibitors. Several PARP1 inhibitors have been recently developed and approved for clinical treatments. We envisaged that PARP inhibition could be potentiated by simultaneously modulating the expression of PARP 1 and the enzyme activity, by a two-pronged strategy. A noncanonical G-quadruplex-forming sequence within the PARP1 promoter has been recently identified. In this study, we explored the potential binding of clinically approved PARP1 inhibitors to the G-quadruplex structure found at the gene promoter region. The results obtained by NMR, CD, and fluorescence titration confirmed by molecular modeling demonstrated that two out the four PARP1 inhibitors studied are capable of forming defined complexes with the PARP1 G-quadruplex. These results open the possibility of exploring the development of better G-quadruplex binders that, in turn, may also inhibit the enzyme

Bacterial ligands as flexible and sensitive detectors in rapid tests for antibodies to SARS-CoV-2

Lateral flow immunoassay (LFIA) is widely employed as point-of-care tests (POCT) for the diagnosis of infectious diseases. The accuracy of LFIA largely depends on the quality of the immunoreagents used. Typical LFIAs to reveal the immune response to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) employ anti-human immunoglobulin (hIG) antibodies and recombinant viral antigens, which usually are unstable and poorly soluble. Broad selective bacterial proteins, such as Staphylococcal protein A (SpA) and Streptococcal protein G (SpG) can be considered alternatives to anti-hIG to increase versatility and sensitivity of serological LFIAs because of their high binding capacity, interspecies reactivity, and robustness. We developed two colorimetric LFA devices including SpA and SpG linked to gold nanoparticles (GNP) as detectors and explored the use of a specific, stable, and soluble immunodominant fraction of the nucleocapsid protein from SARS-CoV-2 as the capturing agent. The optimal amount of SpA-GNP and SpG-GNP conjugates and the protein-to-GNP ratios were defined through a full factorial experimental design to maximize the diagnostic sensitivity of the LFIAs. The new LFA devices were applied to analyze 105 human serum samples (69 positive and 36 negatives according to reference molecular diagnostic methods). The results showed higher sensitivity (89.9%, 95% CI 82.7-97.0) and selectivity (91.7%, 82.6-100) for the SpA-based compared to the SpG-based LFA. In addition, 18 serum samples from cats and dogs living with COVID-19 patients were analyzed and 14 showed detectable levels of anti-SARS-CoV-2 antibodies, thus illustrating the flexibility of the SpA- and SpG-based LFAs

Impairment of T cell development and acute inflammatory response in HIV-1 Tat transgenic mice

Immune activation and chronic inflammation are hallmark features of HIV infection causing T-cell depletion and cellular immune dysfunction in AIDS. Here, we addressed the issue whether HIV-1 Tat could affect T cell development and acute inflammatory response by generating a transgenic mouse expressing Tat in lymphoid tissue. Tat-Tg mice showed thymus atrophy and the maturation block from DN4 to DP thymic subpopulations, resulting in CD4(+) and CD8(+) T cells depletion in peripheral blood. In Tat-positive thymus, we observed the increased p65/NF-κB activity and deregulated expression of cytokines/chemokines and microRNA-181a-1, which are involved in T-lymphopoiesis. Upon LPS intraperitoneal injection, Tat-Tg mice developed an abnormal acute inflammatory response, which was characterized by enhanced lethality and production of inflammatory cytokines. Based on these findings, Tat-Tg mouse could represent an animal model for testing adjunctive therapies of HIV-1-associated inflammation and immune deregulation