FK228 augmented temozolomide sensitivity in human glioma cells by blocking PI3K/AKT/mTOR signal pathways.
Temozolomide is a novel cytotoxic agent currently used as first-line chemotherapy for glioblastoma multiforme (GBM). Romidepsin (FK228), a histone deacetylase inhibitor, is a promising new class of antineoplastic agent with the capacity to induce growth arrest and/or apoptosis of cancer cells. However, combination of the two drugs in glioma remains largely unknown. In the present study, we evaluated the combinatory effects of FK228 with TMZ in glioma, and its molecular mechanisms responsible for these effects. Glioma cell lines were treated with TMZ, FK228 or the combination of drugs. The resistance effect including cytotoxicity and apoptosis was determined in glioma cells, respectively. We further evaluated the effects of FK228 in the PI3K/Akt-signaling pathway in vitro. Mice engrafted with 5×106LN382 cells were treated with TMZ, FK228 or the combination of two drugs, and tumor weights and volumes were measured, respectively. FK228 enhanced the cytotoxic effects of TMZ in glioma cells compared to vehicle-treated controls or each drug alone. The combination of FK228 and TMZ-induced apoptosis was demonstrated by increased expression of cleaved-Caspase 3, Bax, cleaved-PARP, and decreased Bcl-2 expression. Furthermore, the expression of key components of the PI3K/Akt-signaling pathway showed that combination of FK228 and TMZ block PI3K/Akt pathways in vitro. This block effect was also confirmed in vivo in mice models. Mice treated with both FK228 and TMZ drugs showed significantly reduced tumor weights and volumes, compared to each drug alone. Our results suggested that FK228 augmented temozolomide sensitivity in human glioma cells partially by blocking PI3K/AKT/mTOR signal pathways. It thus may provide a promising target for improving the therapeutic outcome of TMZ-resistant gliomas, although further studies will be needed.
Departmant of Neurology, The Inner Mongolia People's Hospital, Huhhot, Inner Mongolia 010017, China. Electronic address: wu_yhan@126.com.
YiHan
Y
Wu
Department of Oncology, The Inner Mongolia People's Hospital, Huhhot, Inner Mongolia 010017, China.
Li
L
Dong
Departmant of Neurology, The Inner Mongolia People's Hospital, Huhhot, Inner Mongolia 010017, China.
SaRuLa
S
Bao
Departmant of Neurology, The Inner Mongolia People's Hospital, Huhhot, Inner Mongolia 010017, China.
MeiLing
M
Wang
Departmant of Neurology, The Inner Mongolia People's Hospital, Huhhot, Inner Mongolia 010017, China.
YongLi
Y
Yun
Departmant of Neurology, The Inner Mongolia People's Hospital, Huhhot, Inner Mongolia 010017, China.
RunXiu
R
Zhu
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D003606:Dacarbazine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D047630:Depsipeptides / Q000494:pharmacology / Q000627:therapeutic use*; D004357:Drug Synergism; D005910:Glioma / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D006801:Humans; D051379:Mice; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*; D000077204:Temozolomide; D023041:Xenograft Model Antitumor Assays
D003606:Dacarbazine; D047630:Depsipeptides; D019869:Phosphatidylinositol 3-Kinases; D047428:Protein Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D000077204:Temozolomide; C087123:romidepsin; C546842:MTOR protein, human
Anti-glioma; Drug combination; FK228; K/AKT/mTOR; PI3; Temozolomide