Figure 3.

FOXD3-AS1 contributed to TMZ resistance in U87 cells.

(A) Parental U87 cells and TMZ resistant U87-R cells (5000/well) were seeded into the 96-well plates, followed by six days of 0, 10, 25, 50, 100, 200, 400, and 800 μM TMZ treatment. MTT assay was then conducted to assess cell survival (N = 3). (B) Clone forming assay: U87 and U87-R cell lines were seeded into the 6-cm dishes (800 cells per dish), followed by TMZ treatment at 0 and 50 μM. Representative plates are shown. N = 3. (C) qRT-PCR results showed that FOXD3-AS1 expression was increased in U87-R cells compared to parental U87 cells (N = 3, *p < 0.05). (D) Over-expression of FOXD3-AS1 increased IC₅₀ of TMZ treatment in U87 cells. N = 3. (E) The colony formation assay indicated that U87 cells overexpressing FOXD3-AS1 were more tolerant to TMZ treatment. Representative plates are shown. N = 3. (F) Depletion of FOXD3-AS1 decreased IC₅₀ of TMZ treatment in U87-R cells (N = 3). (G) The colony formation assay also showed that FOXD3-AS1-depleted U87-R cells were more sensitive to TMZ treatment. Representative plates are shown. N = 3.