Pim kinase inhibitors possess anticancer properties through
downregulation of EGFR family in HER2-positive cancer cells
王于菲1 ,王文玲1, 黃偉謙1,2,3,4
Yu-Fei Wang1, Wen-Ling Wang1, Wei-Chien Huang1,2,3,4
1 Graduate Institute of Cancer Biology, China Medical University, Taichung 404, Taiwan
2 Center for Molecular Medicine, China Medical University and Hospital, Taichung 404, Taiwan
3 The Ph.D. Program for Cancer Biology and Drug Discovery, China Medical University, Taichung 404, Taiwan
4 Department of Biotechnology, Asia University, Taichung 413, Taiwan.
The proviral insertion site in moloney murine leukemia virus (PIM) proteins family, including PIM1, PIM2, PIM3, are serine/threonine kinases and promote cell growth, proliferation and drug resistance. PIM1 is overexpressed in many cancer cells and plays critical role in tumorigenesis. Overexpression of Pim-1 has been found to be associated with the increases in protein levels of RTKs, HER3, EPHA2, HER2, and EGFR in prostate cancer cells. Silence of Pim-1 is also accompanied with downergulation of EGFR family. However, it remains unclear whether the kinase activity of Pim-1 is involved in the gene regulation of EGFR family. In this study, treatments with Pim inhibitors significantly reduced the viability of various breast cancer cell lines. Among these cell lines, HER2-positve breast cancer cells were more sensitive to these inhibitors. Inhibition of Pim kinase activity also reduced their migration and invasion activities. Moreover, Pim inhibitors suppressed the viability of acquired lapatinib-resistant HER2-breast cancer cells. Mechanistically, Pim inhibitors reduced the EGFR, HER2, and HER3 both at protein and mRNA levels, and induced apoptosis. These results suggest that Pim-1, relying on its kinase activity, may regulate EGFR family expression at transcriptional level. Our findings also suggests that downregulation of EGFR family by targeting Pim-1 may be a potential therapeutic strategy for HER2-positive breast cancer patients and for circumventing lapatinib resistance. However, identification of the more detail molecular mechanisms awaits further studies.
cells IC50 HER2 SkBr3 3.0733 1.5109 sl/LR6 9.1317 1.1766 sk/LR9 11.0193 1.0393 MCF7 10.6003 0.1269 HER18 7.4117 1.3122 T47D 7.8585 0.0632 T47D Vector 8.6675 0.0032 T47D WT 12.1029 0.1869 BT474 5.7120 1.0470 MDA-MB 231 3.4861 0.0159 HBL-100 6.6468 0.0002 SGI-1776
cells IC50 HER3 SkBr3 3.07 1.23 sl/LR6 9.13 0.24 sk/LR9 11.02 0.31 MCF7 10.60 0.23 HER18 7.41 0.19 T47D 7.86 0.91 T47D Vector 8.67 0.69 T47D WT 12.10 0.27 BT474 5.71 0.67 MDA-MB 231 3.49 0.13 HBL-100 6.65 0.18 SGI-1776
cells IC50 HER3 SkBr3 14.53 1.23 sl/LR6 32.25 0.24 sk/LR9 13.49 0.31 MCF7 78.01 0.23 HER18 18.81 0.19 T47D 238.21 0.91 T47D Vector 145.75 0.69 T47D WT 19.19 0.27 BT474 36.04 0.67 MDA-MB 231 618.59 0.13 HBL-100 100.01 0.18 SMI-4a cells IC50 HER2
SkBr3 14.5346 1.5109 sl/LR6 32.2469 1.1766 sk/LR9 13.4922 1.0393 MCF7 78.0103 0.1269 HER18 18.8149 1.3122 T47D 238.2131 0.0632 T47D Vector 145.7469 0.0032 T47D WT 19.1915 0.1869 BT474 36.0413 1.0470 MDA-MB 231 618.5906 0.0159 HBL-100 100.0110 0.0002 SMI-4a
Conclusions
Abstract
Results
a.
b.
Fig.1 Viability inhibition of breast cancer cell lines by PIM inhibitors (a) Protein levels of EGFR family in
breast cancer cells (b) Cell viability assay of Pim inhibitor in breast cancer cells (c) The correlation between EGFR family and cell viability of Pim inhibitors.
Fig.2 The Pim inhibitors reduce migration and invasion of skBr3 cell (a) Transwell migration and invasion
assays of skBr3 cells treated with SMI-4a (b) and analyzed by cell count.
Fig.4 The Pim inhibitor reduce EGFR family mRNA expression in HER2 high breast cancer cells.(a) The mRNA levels of EGFR ,HER2 and HER3 were analyzed by
real-time RT-PCR in skBr3 cells. Cell treated Pim inhibitor 48hr.
Fig.5 HER family were up-regulated through overexpression of Pim (a) MCF7 cells were
transfected with a Pim-1, an empty vector, or a Pim-1– expressing plasmid for 24 hours.
a.
b.
a.
a.
Fig.3 The Pim inhibitor reduce EGFR family expression in BT474 cell (a) Dose-dependent of
Pim inhibitor in BT474 and skBr3 cells , cells were treated with SMI-4a 48hr. (b) that were treated for varying periods of time with cycloheximide (CHX).
