Human papillomavirus (HPV) is the causative agent in cervical cancer. HPV oncogenes are major drivers of the transformed phenotype, and the cancers remain addicted to these oncogenes. A screen of the human kinome has identified inhibition of Aurora kinase A (AURKA) as being synthetically lethal on the background of HPV E7 expression. The investigational AURKA inhibitor MLN8237/Alisertib selectively promoted apoptosis in the HPV cancers. The apoptosis was driven by an extended mitotic delay in the Alisertib-treated HPV E7-expressing cells. This had the effect of reducing Mcl-1 levels, which is destabilized in mitosis, and increasing BIM levels, normally destabilized by Aurora A in mitosis. Overexpression of Mcl-1 reduced sensitivity to the drug.The level of HPV E7 expression influenced the extent of Alisertibinduced mitotic delay and Mcl-1 reduction. Xenograft experiments with three cervical cancer cell lines showed Alisertib inhibited growth of HPV and non-HPV xenografts during treatment. Growth of non-HPV tumors was delayed, but in two separate HPV cancer cell lines, regression with no resumption of growth was detected, even at 50 days after treatment. A transgenic model of premalignant disease driven solely by HPV E7 also demonstrated sensitivity to drug treatment. Here, we show for the first time that targeting of the Aurora A kinase in mice using drugs such as Alisertib results in a curative sterilizing therapy that may be useful in treating HPV-driven cancers.
When normal human cultured skin fibroblasts were treated with the fluorescent dye rhodamine 6G (R6G), there was a drastic reduction in numbers of intact mitochondria and electron transport chain enzyme activities, despite the fact that mitochondrial DNA (mtDNA) was still present in treated cells. We used this observation to develop a novel system for generating cybrids. When cultured skin fibroblast cells from a patient with the mitochondrial encephalopathy and ragged-red fibers (MERRF) syndrome harboring the A8344G mtDNA mutation and which showed a severe reduction in cytochrome c oxidase activity were treated with R6G and fused to enucleated HeLaCOT cells, the resulting cybrid clones showed recovery of cytochrome c oxidase activity, and were shown to have mtDNA derived solely from the HeLaCOT cell line. R6G has significant advantages over ethidium bromide in removing the mitochondrial elements from cultured cells, and the results reported here demonstrate that this strategy can be used to determine the origin of the genetic defect in patients with electron transport chain abnormalities.
Congenital alveolar proteinosis due to surfactant protein B deficiency is an inherited disease which results in severe respiratory failure in term infants soon after birth. The pathophysiologic basis of this disease is now known to be an inability to synthesise adequate quantities of normally functioning surfactant protein B. We report a male infant with fatal respiratory failure of neonatal onset, and histopathological features typical of those seen in congenital alveolar proteinosis. Molecular analysis of genomic DNA revealed two mutations, the 'common' 121ins2 mutation in exon 4, and a novel 2bp frameshift mutation in exon 5. We believe this is the first Australian case of surfactant protein B deficiency confirmed by molecular analysis.
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