Polyamine aza-cyclic compounds demonstrate anti-proliferative activity in vitro but fail to control tumour growth in vivo

Open Source Antibiotics: Simple Diarylimidazoles Are Potent against Methicillin-Resistant Staphylococcus aureus

Antimicrobial resistance (AMR) is widely acknowledged as one of the most serious public health threats facing the world, yet the private sector finds it challenging to generate much-needed medicines. As an alternative discovery approach, a small array of diarylimidazoles was screened against the ESKAPE pathogens, and the results were made publicly available through the Open Source Antibiotics (OSA) consortium (https://github.com/opensourceantibiotics). Of the 18 compounds tested (at 32 μg/mL), 15 showed >90% growth inhibition activity against methicillin-resistant Staphylococcus aureus (MRSA) alone. In the subsequent hit-to-lead optimization of this chemotype, 147 new heterocyclic compounds containing the diarylimidazole and other core motifs were synthesized and tested against MRSA, and their structure-activity relationships were identified. While potent, these compounds have moderate to high intrinsic clearance and some associated toxicity. The best overall balance of parameters was found with OSA_975, a compound with good potency, good solubility, and reduced intrinsic clearance in rat hepatocytes. We have progressed toward the knowledge of the molecular target of these phenotypically active compounds, with proteomic techniques suggesting TGFBR1 is potentially involved in the mechanism of action. Further development of these compounds toward antimicrobial medicines is available to anyone under the licensing terms of the project.

Polyamidoamine dendrimer liposome-mediated survivin antisense oligonucleotide inhibits hepatic cancer cell proliferation by inducing apoptosis

Polyamidoamine dendrimer (PAMAM) is a new nanometer material, which can transfer the target genes to cells with high efficiency and lower toxicity. This study aims to evaluate antitumor effects of survivin antisense oligonucleotide (survivin-asODN) (carried by polyamidoamine dendrimer liposome) on hepatic cancer in nude mice. Hepatic cancer model was established by injecting SMMC-7721 cells subcutaneously into flanks of nude mice. Polyamidoamine dendrimer and liposome were mixed with survivin-asODN, respectively. The shape and size of complex were observed by transmission electron microscope, and zeta potential was measured by an analytical tool. Encapsulation efficiency and DNA loading level were determined by an ultraviolet spectrophotometer in centrifuging method. Expression of survivin in transplant tumor was measured by Western blotting. No significant difference appeared for diameter and envelopment ratio between PAMAM liposome-survivin-asODN and PAMAM-survivin-asODN (P > 0.05). Both zeta potential and transfection efficiency in PAMAM liposome-survivin-asODN were higher than that in PAMAM-survivin-asODN complex (P < 0.05). Expression of survivin protein and weight of tumors in transplanted tumors in PAMAM liposome-survivin-asODN group was less than that in PAMAM-survivin-asODN group (P < 0.05). Cell apoptosis rate in PAMAM liposome-survivin-asODN group was higher than that of PAMAM-survivin-asODN group (P < 0.05). In conclusion, polyamidoamine dendrimer liposome can deliver survivin-asODN into hepatic transplanted tumor cells effectively. Ployamidoamine dendrimer liposome-mediated survivin-asODN can inhibit hepatic cell proliferation by inducing apoptosis.

Nanofiber-based delivery of therapeutic peptides to the brain

The delivery of therapeutic peptides and proteins to the central nervous system is the biggest challenge when developing effective neuropharmaceuticals. The central issue is that the blood-brain barrier is impermeable to most molecules. Here we demonstrate the concept of employing an amphiphilic derivative of a peptide to deliver the peptide into the brain. The key to success is that the amphiphilic peptide should by design self-assemble into nanofibers wherein the active peptide epitope is tightly wrapped around the nanofiber core. The nanofiber form appears to protect the amphiphilic peptide from degradation while in the plasma, and the amphiphilic nature of the peptide promotes its transport across the blood-brain barrier. Therapeutic brain levels of the amphiphilic peptide are achieved with this strategy, compared with the absence of detectable peptide in the brain and the consequent lack of a therapeutic response when the underivatized peptide is administered.