Effect of retinoids on the proliferation, morphology and expression of glial fibrillary acidic protein of an anaplastic astrocytoma cell line

Abstract

We studied the effect of retinoids on the growth and differentiation of a cell line (U 343 MG-A) derived from a human malignant astrocytoma. Cultures treated with all-trans or 13-cis retinoic acid showed a dose-dependent inhibition of proliferation and a marked reduction in the mean cell number at the plateau phase of growth (3.5 x 10(6) vs. 1 x 10(7) cells/25 cm2) compared with untreated cultures. At confluence, cells treated with all-trans or 13-cis retinoic acid were contact-inhibited, whereas control cultures showed crowding, piling, and overgrowth. All-trans retinol or retinyl acetate did not inhibit growth. Astrocytoma cultures treated with all-trans retinoic acid (10(-6) M) for 5 days were modestly growth-inhibited but by day 16 had the same numbers of cells as controls; cultures that received all-trans retinoic acid for 9 days were markedly growth-inhibited for 7 days after the drug was removed. All-trans and 13-cis retinoic acid (10(-6) M) prevented the EDTA-induced cell detachment seen in control cultures. Strongly adherent all-trans retinoic-acid-treated astrocytoma cells grew at a slower rate than did readily detached all-trans retinoic-acid-treated or control cells. Cell spreading, an increased cytoplasmic:nuclear ratio, and greater numbers of broadly bipolar cells, some bearing thin cytoplasmic processes, were seen in cultures treated with 10(-6) M all-trans or 13-cis retinoic acid. Small tightly packed cuboidal cells and large broadly bipolar cells were seen in astrocytoma cultures from which all-trans retinoic acid was removed on days 5 and 9. Indirect immunofluorescence revealed more intense staining with antiserum to glial fibrillary acidic protein in cultures treated with 10(-6) M all-trans retinoic acid than in control cultures; electron-microscope examination of similarly treated cultures revealed more abundant 8-10 nm intermediate filaments than in control cultures. An enzyme-linked immunosorbent assay showed that all-trans or 13-cis retinoic acid caused a dose-dependent increase in the quantity of glial fibrillary acidic protein in the astrocytoma cells.

N-CoR Pathway Targeting Induces Glioblastoma Derived Cancer Stem Cell Differentiation

“…This would explain the previous observation of increased GFAP expression and moderate growth inhibition in a glioma cell line (U343 MG-A) treated with RA. 20 and represents a novel mechanism of action of RA in glioma therapy. In addition, since the cytoplasmic translocation of N-CoR is triggered by phosphatidyl-inositol-3-OH kinase/Akt1 kinase-dependent phosphorylation, we examined the effect of okadaic acid, a protein phosphatase-1 inhibitor.…”

Retinoic acid and the cyclin dependent kinase inhibitors synergistically alter proliferation and morphology of U343 astrocytoma cells

“…The p16-de®cient, human astrocytoma cell line U343 responds to all-trans RA treatment (Rutka et al, 1988). Figure 1 shows that RA inhibits U343 proliferation ( Figure 1a) and induces morphological changes (Figure 1b ± c).…”

“…Retinoic acid (RA) treatment of these cells inhibits proliferation, alters morphology, and increases the expression and organization of a marker of glial di erentiation, glial ®brillary acidic protein (GFAP) (Rutka et al, 1988). In the present study, we sought to determine the relationship between RA-induced di erentiation and the expression of several key cell cycle regulators.…”

Role of glial filaments in cells and tumors of glial origin: a review

“…In an earlier study, all-trans and 13-cis retinoic acid (10 -6 M) were effective in decreasing the proliferation of GFAP-positive U-343MG-A astrocytoma cells and in increasing the amount of GFAP produced, as measured by enzyme-linked immunosorbent assay. [97] In another study, it was shown that ECM proteins derived from normal human leptomeningeal cells effectively stopped the proliferation of U-343MG-A astrocytoma cells and induced differentiation of these cells as calculated by a quantitative increase in cellular GFAP. [96,98] The results from these studies suggest that the upregulation of GFAP in GFAP-positive astrocytoma cells is associated with alterations in astrocytoma growth and morphology.…”