ALPK2 is crucial for luminal apoptosis and DNA repair-related gene expression in a three-dimensional colonic-crypt model.
BACKGROUND
Oncogenic KRAS signaling is dysregulated in a three-dimensional (3D)-specific manner in human colorectal cancer (CRC) HCT116 cells. However, the identity of the crucial genes which are down-regulated through oncogenic KRAS in 3D cultures remains unclear.


METHODS
We established a specific anti-alpha-kinase 2 (ALPK2) antibody and addressed the ALPK2 function in HKe3 cells, which are HCT116 cells with a disruption in oncogenic KRAS, in a 3D colonic-crypt model.


RESULTS
In HKe3 cells grown in 3D culture, ALPK2 siRNA inhibited luminal apoptosis and reduced the expression of cleaved caspase-3. Furthermore, ALPK2 siRNA reduced the expression of DNA repair genes. Reduced expression of ALPK2 mRNA was found to be correlated with clinical colorectal adenomas in a public dataset of gene expression analyses.


CONCLUSIONS
ALPK2, down-regulated by oncogenic KRAS, is crucial for luminal apoptosis and expression of DNA repair-related genes, possibly in the transition of normal colonic crypt to adenoma.
Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan.
Yasuhiro
Y
Yoshida
Toshiyuki
T
Tsunoda
Keiko
K
Doi
Takahiro
T
Fujimoto
Yoko
Y
Tanaka
Takeharu
T
Ota
Masahiro
M
Ogawa
Hiroshi
H
Matsuzaki
Masahide
M
Kuroki
Akinori
A
Iwasaki
Senji
S
Shirasawa
D017209:Apoptosis / Q000235:genetics*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000473:pathology; D015179:Colorectal Neoplasms / Q000201:enzymology* / Q000235:genetics; D004260:DNA Repair / Q000235:genetics*; D005455:Fluorescent Antibody Technique; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D045325:HCT116 Cells; D006801:Humans; D047468:Immunoprecipitation; D018613:Microscopy, Confocal; D020411:Oligonucleotide Array Sequence Analysis; D010770:Phosphotransferases / Q000235:genetics / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D034741:RNA, Small Interfering; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D018631:ras Proteins / Q000235:genetics
C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D034741:RNA, Small Interfering; C574100:ALPK2 protein, human; D010770:Phosphotransferases; D011494:Protein Kinases; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins