Agarwal, Nitin Kumar

English

Methotrexate (MTX) was first introduced as
a cytotoxic agent that inhibits nucleotide biosynthesis in various
cancer disorders. Accumulating evidences suggest that MTX inhibits
the proliferation of malignant cells by inhibiting
5-aminoimidazole-4-carbox-amide ribonucleotide transformylase,
isoprenylcysteine carboxyl methyltransferase and NF-kappaB
transcription factor. These observations indicate that MTX could
have additional molecular targets that are therefore unappreciated.
To get insights into the complex molecular mechanisms of MTX
induced apoptosis in acute promyelocytic leukemia cells (HL 60), we
conducted an investigation incorporating cysteine labeled
differential in gel electrophoresis combined with mass
spectrometry. Initial experimental analysis revealed that 24
proteins were differentially expressed (p > 0.05) in HL 60 cell
proteome after addition of 2.5 µM MTX for 72 hours. The majority of
MTX induced proteins were ascribed to the endoplasmic reticulum
(ER) chaperones, glycolytic enzymes and the mitochondrial
transmembrane electron transport system (MTETS). In particular, we
noted that three structural alpha4, alpha5, alpha7; a
non-catalytically beta3 and two 26S regulatory proteasome subunits
were significantly down regulated in MTX treated HL 60 cell. We
further showed in HL 60 cells that MTX induces ER chaperones,
suppresses the NF-kappaB subunit p65, disturbs the mitochondrial
transmembrane potential (Äøm) and generates reactive oxygen species
(ROS) in a time dependent manner. All together, our findings
revealed that MTX alter the level of a variety of proteins involved
in the NF-kappaB associated proteasome complex formation, ER
stress, and the MTETS. Their identification as molecular targets of
MTX may provide new impulse in the understanding of apoptotic
activities in acute promyelocytic leukaemia cell line

Georg-August-University Göttingen

Proteome-wide Identification of New Molecular Targets Affected by Methotrexate in Acute Promyelocytic Leukaemia Cell Line

https://ediss.uni-goettingen.de/bitstream/11858/00-1735-0000-000D-F227-3/1/agarwal.pdf

Proteome-wide Identification of New Molecular Targets Affected by Methotrexate in Acute Promyelocytic Leukaemia Cell Line

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Georg-August-University Göttingen