Xeroderma pigmentosum complementation group F: A rare cause of cerebellar ataxia with chorea

The complementation group F of Xeroderma pigmentosum (XP-F) is rare in the Caucasian population, and usually devoid of neurological symptoms. We report two cases, both Caucasian, who exhibited progressive cerebellar ataxia, chorea, a mild subcortical frontal cognitive impairment, and in one case severe polyneuropathy. Brain MRI demonstrated cerebellar (2/2) and cortical (1/2) atrophy. Both patients had only mild sunburn sensitivity and no skin cancer. Mini-exome sequencing approach revealed in ERCC4, two heterozygous mutations, one of which was never described (c.580-584+1delCCAAGG, exon 3), in the first case, and an already reported homozygous mutation, in the second case. These cases emphasize that XP-F is a rare cause of recessive cerebellar ataxia and can in some cases clinically mimic Huntington's disease due to chorea and executive impairment. The association of ataxia, chorea, and sun hypersensitivity are major guidance for the diagnosis, which should not be missed, in order to prevent skin neoplastic complications.

The cytoprotective drug amifostine modifies both expression and activity of the pro-angiogenic factor VEGF-A

BACKGROUND

Amifostine (WR-2721, delivered as Ethyol) is a phosphorylated aminothiol compound clinically used in addition to cis-platinum to reduce the toxic side effects of therapeutic treatment on normal cells without reducing their efficacy on tumour cells. Its mechanism of action is attributed to the free radical scavenging properties of its active dephosphorylated metabolite WR-1065. However, amifostine has also been described as a potent hypoxia-mimetic compound and as a strong p53 inducer; both effects are known to potently modulate vascular endothelial growth factor (VEGF-A) expression. The angiogenic properties of this drug have not been clearly defined.

METHODS

Cancer cell lines and endothelial cells were used in culture and treated with Amifostine in order to study (i) the expression of angiogenesis related genes and proteins and (ii) the effects of the drug on VEGF-A induced in vitro angiogenesis.

RESULTS

We demonstrated that the treatment of several human cancer cell lines with therapeutical doses of WR-1065 led to a strong induction of different VEGF-A mRNA isoforms independently of HIF-1alpha. VEGF-A induction by WR-1065 depends on the activation of the eIF2alpha/ATF4 pathway. This up-regulation of VEGF-A mRNA was accompanied by an increased secretion of VEGF-A proteins fully active in stimulating vascular endothelial cells (EC). Nevertheless, direct treatment of EC with amifostine impaired their ability to respond to exogenous VEGF-A, an effect that correlated to the down-regulation of VEGFR-2 expression, to the reduction in cell surface binding of VEGF-A and to the decreased phosphorylation of the downstream p42/44 kinases.

CONCLUSIONS

Taken together, our results indicate that amifostine treatment modulates tumour angiogenesis by two apparently opposite mechanisms - the increased VEGF-A expression by tumour cells and the inhibition of EC capacity to respond to VEGF-A stimulation.

The effect of imatinib (Glivec) on scleroderma and normal dermal fibroblasts: a preclinical study

BACKGROUND

Scleroderma skin overexpresses the platelet-derived growth factor receptor beta-subunit (PDGFR-beta) in dermal vessels and PDGFR-beta messenger RNA in cultured fibroblasts. Moreover, increased levels of PDGF and stimulatory autoantibodies to PDGFR have been identified in the serum of scleroderma patients.

OBJECTIVE

Imatinib being an inhibitor of tyrosine kinase receptors such as PDGFR, its effect on scleroderma fibroblasts was evaluated in vitro as a preclinical therapeutic step.

METHODS

The effect of imatinib on fibroblasts grown from normal or involved/uninvolved scleroderma skin was studied by Western blot and the methyltetrazolium test. The pattern of distribution of PDGFR-beta in scleroderma versus normal skin was studied by immunohistochemistry.

RESULTS

In vitro, imatinib inhibited the proliferation of normal dermal and scleroderma fibroblasts at least partly via the inhibition of the phosphorylation of PDGFR. PDGFR-beta was expressed in the epidermis and adnexae in 5 lesional scleroderma biopsies and not in controls.

CONCLUSION

This study suggests that imatinib can serve as therapy to limit dermal fibroblast proliferation in scleroderma.

Protection of normal human reconstructed epidermis from UV by catalase overexpression

Reactive oxygen species (ROS) generated by ultraviolet (UV) irradiation are counterbalanced by endogenous antioxidant systems. To test the hypothesis of a novel photoprotective approach, we irradiated epidermis reconstructed with normal human keratinocytes overexpressing sustainably lentivirus-mediated catalase (CAT), copper/zinc superoxide dismutase (CuZnSOD) or manganese superoxide dismutase (MnSOD) enzymes. We found that following UVB irradiation there was a marked decrease in sunburn cell formation, caspase-3 activation and p53 accumulation in human reconstructed epidermis overexpressing CAT. Moreover, UVA-induced hypertrophy and DNA oxidation (8-oxodeoxyguanosine) were decreased by CAT overexpression. These effects were not achieved by overexpression of CuZnSOD or MnSOD. In conclusion, vector-mediated CAT overexpression could be a promising photoprotective tool against deleterious effects of UV irradiation such skin cancer especially in monogenic/polygenic photosensitive disorders characterized by ROS accumulation.