Chemical synthesis and biochemical properties of cholestane-5α,6ß-diol-3-sulfonate: A non-hydrolysable analogue of cholestane-5α,6ß-diol-3ß-sulfate.

Cholestane-3ß,5α,6ß-triol (CT) is a primary metabolite of 5,6-epoxycholesterols (5,6-EC) that is catalyzed by the cholesterol-5,6-epoxide hydrolase (ChEH). CT is a well-known biomarker for Niemann-Pick disease type C (NP-C), a progressive inherited neurodegenerative disease. On the other hand, CT is known to be metabolized by the 11ß-hydroxysteroid-dehydrogenase of type 2 (11ß-HSD2) into a tumor promoter named oncosterone that stimulates the growth of breast cancer tumors. Sulfation is a major metabolic transformation leading to the production of sulfated oxysterols. The production of cholestane-5α,6ß-diol-3ß-O-sulfate (CDS) has been reported in breast cancer cells. However, no data related to CDS biological properties have been reported so far. These studies have been hampered because sulfate esters of sterols and steroids are rapidly hydrolyzed by steroid sulfatase to give free steroids and sterols. In order to get insight into the biological properties of CDS, we report herein the synthesis and the characterization of cholestane-5α,6ß-diol-3ß-sulfonate (CDSN), a non-hydrolysable analogue of CDS. We show that CDSN is a potent inhibitor of 11ß-HSD2 that blocks oncosterone production on cell lysate. The inhibition of oncosterone biosynthesis of a whole cell assay was observed but results from the blockage by CDSN of the uptake of CT in MCF-7 cells. While CDSN inhibits MCF-7 cell proliferation, we found that it potentiates the cytotoxic activity of post-lanosterol cholesterol biosynthesis inhibitors such as tamoxifen and PBPE. This effect was associated with an increase of free sterols accumulation and the appearance of giant multilamellar bodies, a structural feature reminiscent of Type C Niemann-Pick disease cells and consistent with a possible inhibition by CDSN of NPC1. Altogether, our data showed that CDSN is biologically active and that it is a valuable tool to study the biological properties of CDS and more specifically its impact on immunity and viral infection.

Shelf Life and Efficacy of Diagnostic Eye Drops.

SIGNIFICANCE: Pharmaceutical companies recommend discarding ophthalmic drugs 28 days after opening. This study shows that diagnostic eye drops have a low risk of contamination over a 7-month period in a controlled clinical setup. The diagnostic efficiency seems to be preserved over this period. PURPOSE: The aim of this study was to evaluate the preservation period and the efficacy of ophthalmic preparations, such as 0.5% proparacaine hydrochloride, 1% tropicamide, 2.5% phenylephrine hydrochloride, and 1% cyclopentolate hydrochloride ophthalmic solution in a clinical and controlled setting. METHODS: Thirty-eight primary eye care students were recruited to participate in the study. They used 25 bottles of each diagnostic drop at the Clinique Universitaire de la Vision for a 7-month period. An analysis of the bacterial contamination was repeated 10 times using both an agar plate and a nutrient broth at 0, 2, 4, 6, and 8 weeks and at 3, 4, 5, 6, and 7 months. The anesthetic, mydriatic, and cycloplegic effects were tested after 7 months of use and compared with nonopened ophthalmic bottles. RESULTS: During the 7-month period, 4971 drops of proparacaine, 3219 drops of tropicamide and phenylephrine, and 1896 drops of cyclopentolate were administered to the patients. A total of 226 contacts between bottles and biological tissues were reported. After the 10 inoculation sessions on the agar medium at the predetermined times, no bacterial and fungal contamination was noted. No patient reported eye infections for 2 weeks after the drop instillation. Moreover, there was no difference in the efficacy when compared with new drops. CONCLUSIONS: According to the results of the current study, diagnostic eye drops can be used with a low contamination risk beyond the recommendation date of 28 days up to 7 months, with the same efficacy, in a controlled clinical context.