Knockdown on aPKC-ι inhibits epithelial-mesenchymal transition, migration and invasion of colorectal cancer cells through Rac1-JNK pathway.

Abstract

BACKGROUND:

Atypical protein kinase C-ι (aPKC-ι) is an oncogenic factor, and required for the epithelial-mesenchymal transition (EMT) of different types of cancer. Our study aimed to investigate the role of aPKC-ι in the EMT, migration and invasion of colorectal cancer (CRC) cells.

METHODS:

Expression of aPKC-ι was evaluated in CRC cell lines treated with TGF-β1 using qPCR and western blot. After aPKC-ι was knocked down using shRNA, migration and invasion abilities of CRC cell lines were evaluated by wound healing assay and transwell assay, respectively. Activation status of downstream signaling factors of aPKC-ι, including Rac1, JNK, STAT3 and β-catenin, was measured using western blot. Furthermore, auranofin, an aPKC-ι inhibitor, was used to treat CRC cell lines to investigate its possible inhibition on the EMT of CRC cell lines, as well as on the expression of aPKC-ι and its downstream signaling factors.

RESULTS:

TGF-β1 induced the expression of aPKC-ι in CRC cells, and knockdown on aPKC-ι inhibited the TGF-β1-induced EMT, migration and invasion of CRC cells. Interestingly, Rac1 GTPase level was decreased when aPKC-ι was knocked down, and overexpression of Rac1G12V rescued the cell EMT, migration and invasion in CRC cells as inhibited by sh-aPKC-ι. Moreover, knockdown on aPKC-ι suppressed the phosphorylation of JNK and STAT3, and nuclear translocation of β-catenin. The aPKC- ι inhibitor, Auranofin, showed similar inhibitory effects as aPKC-ι knockdown.

CONCLUSION:

Knockdown on aPKC-ι inhibited the EMT, migration and invasion of CRC cells through suppressing of Rac1-JNK pathway. Those findings indicate that aPKC-ι may serve as a novel therapeutic target for CRC.

• Authors: Guang-Sheng Du, Yuan Qiu, Wen-Sheng Wang, Ke Peng, Zhi-Cao Zhang, Xiang-Sheng Li, Wei-Dong Xiao, Hua Yang
• Journal: Experimental and molecular pathology (Exp Mol Pathol) Vol. 107 Pg. 57-67 (04 2019) ISSN: 1096-0945 [Electronic] Netherlands
• PMID: 30465755 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2018 Elsevier Inc. All rights reserved.

Chemical References

• Isoenzymes
• RAC1 protein, human
• Protein Kinase C
• protein kinase C lambda
• rac1 GTP-Binding Protein

Topics

• Cell Line, Tumor
• Cell Movement (physiology)
• Colorectal Neoplasms (pathology)
• Epithelial-Mesenchymal Transition (physiology)
• Humans
• Isoenzymes (metabolism)
• MAP Kinase Signaling System (physiology)
• Neoplasm Invasiveness (physiopathology)
• Protein Kinase C (metabolism)
• rac1 GTP-Binding Protein (metabolism)