Abstract: Folylpolyglutamate synthetase (FPGS) is the key enzyme that converts chemotherapy drug Methotrexate (MTX) into MTXPG. The expression level of FPGS directly influences MTX-sensitivity of tumor cells. Compared with B-cell acute lymphocytic leukemia (B-ALL), T-cell acute lymphocytic leukemia (T-ALL) cells express a lower level of FPGS, which results in insensitivity of the cells to MTX. Our previous work has demonstrated that 279 bp mbr element located within the 3′-UTR of the BCL2 gene possesses enhancer function. In this study, FPGS expression plasmid containing mbr element at the 5′ upstream of the gene was constructed and transfected into Jurkat cells to sensitize the cells to MTX. Western blotting and MTT assay were applied to detect the FPGS expression level and suppression rate of the cells treated by MTX, respectively. We found that the mbr enhanced the expression of FPGS significantly and increased sensitivity of Jurkat cells to MTX efficiently, while FPGS expression plasmid without mbr element had less effect. Our data provides a new clue for the clinical application of mbr regulatory element and may contribute to improvement of MTX treatment in T-ALL.

Key words: FPGS, mbr element, overexpression, MTX-sensitivity