ROLE OF HYDROXYMETHYLGLUTHARYL-COENZYME-A REDUCTASE (HMGCR) IN THE GENERATION OF STEM CELL STATES IN BREAST CANCER

MARKS MP; ISAJA L; RODRIGUEZ VARELA MS; MUCCI S; VERA M; MORRIS O; ROMORINI L; VIDELA RICHARDSON G; CHASSEING NA; CALVO JC; VELLON L

Congreso; LXV REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA (SAIC); 2020

Sociedad Argentina de Investigación Clínica

M2, Morris O2, Romorini L2, Videla-Richardson G2, ChasseingNA1, Calvo JC1, Vellón L1.1. Laboratorio de Células Madre, Instituto de Biología y Me- dicina Experimental (IBYME-CONICET).2. Laboratorio de Investigación Aplicada en Neurociencias (LIAN-CONICET), Fundación para la Lucha contra las Enfer- medades Neurológicas de la Infancia (FLENI).Alterations of lipid metabolism are important players in tumor pro- gression, including the generation and maintenance of cancer stem cell (CSC) states. Here, we addressed whether the rate limiting enzyme in cholesterol biosynthesis, HMGCR, was associated with stem cell phenotypes. First, we analyzed HMGCR expression by RT-qPCR in the pluripotent stem cells lines WA-09 and FN2.1, in several CSCs lines derived from glioblastomas and in a breast can- cer (BC) stem-like state with HMGCR overexpression, generated in our lab (MCF-7/CR). With the exception of two of the glioma CSCs, the rest of the cell lines showed increased levels of HMGCR whencompared to MCF-7 BC cell line. To further determine the role ofHMGCR in the generation of stem states in BC, we infected MCF-7 cells with lentiviral vectors expressing the Yamanaka reprogram- ming factors and obtained four clones, termed MCF-7/Rep clones #3, #5, #6 and #9. We analyzed the expression of the pluripotency factors Oct4, Sox2 and Nanog by qRT-PCR, using an iPSCs cell line (FAD) as a positive control. All MCF-7/Rep cells showed increased levels of Sox2, up to 10-fold (MCF-7/Rep clone #3) when compared to MCF-7 parental cells. Oct4 was increased up to 10-fold in MCF-7/Rep #9 cells to levels comparable to those observed in FAD iPS cells. Immunofluorescent detection of Sox2, Oct4 and Nanog in two clones (MCF-7/Rep #3 and #9) corroborated the observations found at the transcriptional level. There was no expression of the pluripotency surface markers SSEA-4, TRA-1-60 and the alkaline phosphatase assay was negative. Interestingly, HMGCR expres- sion in the MCF-7/Rep cells was decreased when compared to their parental counterpart. These results suggest that the MCF-7/ Rep clones may be intermediate states between a cancer cell and a bona fide pluripotent cell, and that, while HMGCR expression is unstable during reprogramming, is associated with well-established stem cells phenotypes in transformed and non-transformed cells.