Publications

Neuroblastoma (NB) is among the most common malignancies in children and represents a therapeutic challenge in pediatric oncology. p53 family proteins play a critical role in protecting cells from genomic instability and malignant transformation. However, in NB, their activities are often inhibited by interacting proteins such as MDM2. The interplay between p53 family pathway and N-Myc, a key biomarker of poor prognosis, is also a critical factor in NB pathogenesis. Herein, we disclose 1-(dibromomethyl)-3,4,6-trimethoxy-9H-xanthen-9-one (LEM3) as a new p53 family-activating agent with potent NB anticancer activity. At 0.13-2.1 mu M, LEM3 inhibited the growth of several NB cell lines. Its activity was further evidenced in spheroids, patient-derived NB cells, and in a vasculature stiffness-based model of MYCN-amplified NB cells. This growth-inhibitory effect was associated with cell cycle arrest and apoptosis, in SH-SY5Y and SK-N-BE(2) NB cells, without apparent acquisition of resistance. LEM3 inhibited cell migration and invasion and reduced the expression of NB-related prognostic markers, particularly MYCN mRNA and protein levels. LEM3 released p53, TAp63, and TAp73 from their interaction with MDM2 both in a yeast-based assay and NB cells; for p53, this led to increased protein stabilization, DNA-binding ability, and transcriptional activity. Fluorescence quenching and docking analyses suggested that LEM3 binds to p53, TAp63, and TAp73 at the MDM2-binding site within their transactivation domain. LEM3 also synergies with doxorubicin and cisplatin in NB cells. Given the central role of the p53 family MDM2-MYCN axis in NB pathogenesis, our findings support LEM3 as a promising compound for advancing NB targeted therapy.

JTD Keywords: Amplification, Cell-lines, Expression, High-risk neuroblastoma, Mdm2, Mutant p53, N-myc, N-myc oncogene, Neuroblastoma, P53 family proteins, P53/mdm2/p14(arf) pathway, P73, Sensitizes neuroblastoma, Targeted anticancer therapy, Xanthone derivative

Malaria eradication has for decades been on the global health agenda, but the causative agents of the disease, several species of the protist parasite Plasmodium, have evolved mechanisms to evade vaccine-induced immunity and to rapidly acquire resistance against all drugs entering clinical use. Because classical antimalarial approaches have consistently failed, new strategies must be explored. One of these is nanomedicine, the application of manipulation and fabrication technology in the range of molecular dimensions between 1 and 100 nm, to the development of new medical solutions. Here we review the current state of the art in malaria diagnosis, prevention, and therapy and how nanotechnology is already having an incipient impact in improving them. In the second half of this review, the next generation of antimalarial drugs currently in the clinical pipeline is presented, with a definition of these drugs’ target product profiles and an assessment of the potential role of nanotechnology in their development. Opinions extracted from interviews with experts in the fields of nanomedicine, clinical malaria, and the economic landscape of the disease are included to offer a wider scope of the current requirements to win the fight against malaria and of how nanoscience can contribute to achieve them. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

JTD Keywords: antibody-bearing liposomes, antimalarial drugs, combination therapies, drug-delivery strategies, malaria diagnosis, malaria prophylaxis, malaria therapy, nanocarriers, nanomedicine, nanoparticles, nanotechnology, plasmodium, plasmodium-falciparum, red-blood-cells, targeted delivery, targeted drug delivery, vitro antimalarial activity, Antimalarial drugs, Isothermal amplification lamp, Malaria diagnosis, Malaria prophylaxis, Malaria therapy, Nanocarriers, Nanomedicine, Nanotechnology, Plasmodium, Targeted drug delivery

The nucleoid-associated proteins Hha and YdgT repress the expression of the toxin a-hemolysin. An Escherichia coli mutant lacking these proteins overexpresses the toxin a-hemolysin encoded in the multicopy recombinant plasmid pANN202-312R. Unexpectedly, we could observe that this mutant generated clones that no further produced hemolysin (Hly(-)). Generation of Hly(-) clones was dependent upon the presence in the culture medium of the antibiotic kanamycin (km), a marker of the hha allele (hha::Tn5). Detailed analysis of different Hly(-) clones evidenced that recombination between partial IS91 sequences that flank the hly operon had occurred. A fluctuation test evidenced that the presence of km in the culture medium was underlying the generation of these clones. A decrease of the km concentration from 25 mg/l to 12.5 mg/l abolished the appearance of Hly(-) derivatives. We considered as a working hypothesis that, when producing high levels of the toxin (combination of the hha ydgT mutations with the presence of the multicopy hemolytic plasmid pANN202-312R), the concentration of km of 25 mg/l resulted subinhibitory and stimulated the recombination between adjacent IS91 flanking sequences. To further test this hypothesis, we analyzed the effect of subinhibitory km concentrations in the wild type E. coli strain MG1655 harboring the parental low copy number plasmid pHly152. At a km concentration of 5 mg/l, subinhibitory for strain MG1655 (pHly152), generation of Hly(-) clones could be readily detected. Similar results were also obtained when, instead of km, ampicillin was used. IS91 is flanking several virulence determinants in different enteric bacterial pathogenic strains from E. coli and Shigella. The results presented here evidence that stress generated by exposure to subinhibitory antibiotic concentrations may result in rearrangements of the bacterial genome. Whereas some of these rearrangements may be deleterious, others may generate genotypes with increased virulence, which may resume infection.

JTD Keywords: Promotes horizontal dissemination, Enterica serovar typhimurium, Escherichia-coli strains, Insertion-sequence IS91, H-NS, Adaptive amplification, Pathogenicity islands, Hemolysin