RESUMO
Background: Although several roles of 27-hydroxycholesterol (27-HC), the most abundant oxysterol in blood circulation, in cancers have been elucidated, its impact on breast cancer proliferation and its pathway remain unknown. Materials and Methods: The effect of 27-HC on breast cancer cell proliferation and its pathway was evaluated using Michigan Cancer Foundation - 7 (MCF-7) and M.D. Anderson - Metastatic Breast 231 (MDA-MB-231) cell lines. The MTT assay was applied after 24- and 48-hour incubation to distinguish cell proliferation. To determine the cause of different viability results from the MTT assay, the Annexin-FITC/PI test was used at concentrations of 0.1, 1, and 10 µM after 24- and 48-hour incubation. Results: 27-HC in concentrations of 5, 10, and 20 µM induced cell cytotoxicity compared with control. Also, the annexin V conjugated with fluorescein isothiocyanate/propidium iodide (Annexin-FITC/PI) test revealed an increase in total apoptotic cells treated with 0.1, 1, and 10 µM of 27-HC after 48 hours (P value < 0.05). Besides, the cytotoxic effect of 27-HC was observed at 10 µM concentration in both cell lines, MCF-7 and MDA-MB-231 (P value < 0.05). Conclusion: The identification of 27-HC's cytotoxic effects on both estrogen receptor (ER)-negative and ER-positive breast cancer cell lines is a novel discovery that may be linked to LXRß.
RESUMO
Methanol can inhibit cellular aerobic respiration pathway and causes cell hypoxia specially in optic neurons. Despite using many drugs, methanol-induced optic neuropathy (MION) still has a poor prognosis. Here we present a case of MION which is managed by a combination of intravenous and intravitreal erythropoietin in addition to corticosteroids.