NK3 and NK4 of HGF enhance filamin production via STAT pathway, but not NK1 and NK2 in human breast cancer cells.
OBJECTIVE
The purpose of this study was to reveal the effects of hepatocyte growth factor (HGF) variants on human breast cancer cells and the differential signaling pathways of the variants in controlling cell proliferation and invasion.


METHODS
Four HGF variants (NK1, NK2, NK3, and NK4) were created by gene engineering, and the variant DNA fragments were cloned into pGEM-T for DNA sequencing and then transferred to a pTrcHis-A plasmid for expression. Recombinant proteins were purified from Escherichia coli, and a series of assays, including cell proliferation and invasion were carried out. Phosphorylated components in the HGF-c-Met and STAT (signal transducers and activators of transcription) pathways were detected by immunoprecipitation-Western blots.


RESULTS
All the HGF variants inhibited the vigorous growth of the cancer cells differently and dose-dependently, but the effect of NK3 or NK4 was 7.5-fold higher than NK1 or NK2. In addition, the assays for the phosphorylation of the components in the HGF-c-Met pathway showed that NK3 and NK4 inhibited invasion via the STAT pathway, whereas NK1 and NK2 were via the HGF-c-Met pathway.


CONCLUSIONS
The engineered HGF variants inhibited the proliferation of human breast cancer cells via different signaling pathways, NK1 and NK2 via the HGF-c-Met pathways, and NK3 and NK4 via the STAT pathway, the latter being a possible key route for the inhibition of cell invasion. All of the HGF variants have the potential to become pharmaceutical drugs in the treatment of human cancer.
Yin
Ya-ling
YL
China Medical University School of Medicine, Taichung 40402, Taiwan, China.
Chen
Hsiu-ling
HL
Kuo
Hsiu-maan
HM
He
Shi-ping
SP
D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D003285:Contractile Proteins / Q000096:biosynthesis*; D004247:DNA / Q000096:biosynthesis / Q000235:genetics; D005260:Female; D064448:Filamins; D017228:Hepatocyte Growth Factor / Q000502:physiology*; D006801:Humans; D008840:Microfilament Proteins / Q000096:biosynthesis*; D009361:Neoplasm Invasiveness / Q000473:pathology; D019859:Proto-Oncogene Proteins c-met / Q000235:genetics / Q000502:physiology; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D050791:STAT Transcription Factors / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*
D003285:Contractile Proteins; D064448:Filamins; D008840:Microfilament Proteins; D011994:Recombinant Proteins; D050791:STAT Transcription Factors; D017228:Hepatocyte Growth Factor; D004247:DNA; D019859:Proto-Oncogene Proteins c-met