Growth Inhibition Of Human Cells Research Articles

ROS-Scavenger and Radioprotective Efficacy of the New PrC-210 Aminothiol

To identify new aminothiol radioprotectors that are active when applied topically and have fewer side effects when administered systemically, a new family of aminothiol radioprotectors was designed and synthesized. Three key elements in the aminothiol design were, (1) small size for efficient transmembrane diffusion, (2) positive charged amines in alkyl backbone for strong ionic interaction with DNA backbone, and (3) a perpendicular, alkyl side-chain with a terminal thiol that is projected away from the DNA backbone to enable reactive oxygen species scavenging around DNA. Several in vitro assays were used to characterize the prototype aminothiol, PrC-210, for efficacy: protection against reactive oxygen species-induced plasmid DNA nicking, mass spectrometry to detect aminothiol-reactive oxygen species by-products, S. typhimurium mutagenesis, human cell growth inhibition, Western blot for p21 expression, and FACS analysis. Additionally, two in vivo assays were used to assess radioprotective efficacy; a Sprague-Dawley rat dorsal skin radiodermatitis assay was developed to screen for aminothiol efficacy when topically applied, and ICR mouse survival was scored after systemic PrC-210 administration and whole-body radiation. PrC-210 efficiently scavenged reactive oxygen species and completely protected supercoiled plasmid DNA against reactive oxygen species-induced damage. Neither PrC-210 nor its analog PrC-211 were bacterial mutagens. In cell culture, PrC-210 application to diploid human fibroblasts showed: (1) inhibition of cell growth with an IC(70) of 4.1 mM, (2) induced levels of p21 expression, and (3) a G(1)/S-cell cycle block that was reversed after washout of PrC-210-containing medium. In rodents, PrC-210 was an effective radioprotector showing: (1) complete prevention of Grade 2-3 radiodermatitis when applied topically (370 mM in ethanol:propylene glycol:water solution) prior to skin irradiation, (2) complete prevention of Grade 2-3 radiodermatitis when administered by i.p. injection (200 μg/g of body weight) before skin irradiation, (3) 100% survival of mice from an otherwise 100% lethal dose of whole-body radiation (8.75 Gy) when administered by i.p. injection (252 μg/g of body weight = 0.5 × maximum tolerated dose) before irradiation, and (4) a dose reduction factor of 1.6, the same as amifostine. These data suggest that the PrC-210 aminothiol is a plausible candidate for drug development as a human pre-exposure radioprotector.

Dual Dehydrosqualene/Squalene Synthase Inhibitors: Leads for Innate Immune System‐Based Therapeutics

Dual Dehydrosqualene/Squalene Synthase Inhibitors: Leads for Innate Immune System‐Based Therapeutics

The uptake of oligogalacturonide and its effect on growth inhibition, lactate dehydrogenase activity and galactin-3 release of human cancer cells

Anti-tumour activity and membrane permeability of 1kDa oligogalacturonide (PET-pectin), prepared from citrus pectin after 24h hydrolysis, by commercial pectic enzyme produced by Aspergillus niger, on four human cell lines (HepG2, A549, Colo 205, and HEK293) and the uptake of oligogalacturonide by HEK293 cell and BALB/c mouse were investigated. PET-pectin causes a higher value of growth inhibition, lactate dehydrogenase release, and galactin-3 release in human cancer cells, as compared to the human normal HEK293 cell. There was a good correlation between growth inhibition of human cells and the uptake of rhodamine B-PET-pectin content by these cells. Additionally, almost no difference between growth inhibitions of human normal HEK293 cells cultivated with PET-pectin and pectin was found. Total pectin content in the blood of PET-pectin administrated mice increased to a maximum at 2h after oral administration, while it did not increase and change in pectin administrated mice. Our findings suggested that citrus PET-pectin can be developed as a potential dietary supplement in plant origin for cancer prevention.

RNAi of FACE1 protease results in growth inhibition of human cells expressing lamin A: implications for Hutchinson-Gilford progeria syndrome

FACE 1 is the endoprotease responsible for cleavage of prelamin A to lamin A. Transfection of HeLa cells with siRNA for human FACE 1 results in a strong phenotype. Protein and mRNA levels for FACE 1 are knocked down and cell division stops abruptly. Two populations of cells are detected. The first form aberrant mitotic spindles, arrest in mitosis and later enter apoptosis. The second show dramatic changes in nuclear morphology with extensive formation of lobulated nuclei and micronuclei. Using antibodies that specifically recognise prelamin A, but not lamin A, we show that prelamin A accumulates at the nuclear lamina in FACE1 silenced cells, whereas in control cells prelamin A is found in many small nuclear dots, but not at the nuclear lamina. In double knockdown experiments with FACE 1 and lamin A siRNAs, the results depend on which protein is knocked down first. FACE1 knockdown 24 hours prior to lamin A knockdown gives results similar to the single FACE1 knockdown. By contrast, lamin A knockdown 24 hours prior to FACE1 knockdown results in none of the changes described above. Silencing of FACE1 in HL60, a cell line that lacks lamin A, also has no effect. The combined results suggest that prelamin A is a poison in cells subjected to FACE 1 knockdown. Finally, we draw attention to similarities in phenotype between FACE1-silenced HeLa cells and fibroblasts from patients with Hutchinson-Gilford progeria syndrome containing prelamin A mutations that prevent cleavage by the FACE1 endoprotease.