Inhibition of ERKs/Akt-Mediated c-Fos Expression Is Required for Piperlongumine-Induced Cyclin D1 Downregulation and Tumor Suppression in Colorectal Cancer Cells

Feng Gao; Li Zhou; Ming Li; Wenbin Liu; Shuting Yang; Wei Li

doi:10.2147/OTT.S251295

Inhibition of ERKs/Akt-Mediated c-Fos Expression Is Required for Piperlongumine-Induced Cyclin D1 Downregulation and Tumor Suppression in Colorectal Cancer Cells

Onco Targets Ther. 2020 Jun 15:13:5591-5603. doi: 10.2147/OTT.S251295. eCollection 2020.

Authors

Feng Gao^#^{1

2}, Li Zhou^#³, Ming Li^#^{1

4

5}, Wenbin Liu⁶, Shuting Yang², Wei Li^{1

7}

Affiliations

¹ Cell Transplantation and Gene Therapy Institute, The Third Xiangya Hospital, Central South University, Changsha, Hunan 410013, People's Republic of China.
² Department of Ultrasonography, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, People's Republic of China.
³ Department of Pathology, Xiangya Hospital of Central South University, Changsha, Hunan 410013, People's Republic of China.
⁴ Changsha Stomatological Hospital, Changsha, Hunan 410004, People's Republic of China.
⁵ School of Stomatology, Hunan University of Chinese Medicine, Changsha, Hunan 410208, People's Republic of China.
⁶ Department of Pathology, Hunan Cancer Hospital, Changsha, Hunan 410013, People's Republic of China.
⁷ Department of Radiology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, People's Republic of China.

^# Contributed equally.

Abstract

Background: Deregulation of Cyclin D1 and cell cycle progression plays a critical role in tumorigenesis. The natural compound piperlongumine (PL) exhibits potential anticancer effects in various cancer models, but the underlying mechanism needs further elucidation.

Methods: The inhibitory effect of PL on colorectal cancer (CRC) cells was determined by anchorage-dependent and -independent assays. The protein level of Cyclin D1 was examined by immunoblot (IB) and immunohistochemical staining (IHC). The mRNA level was determined by qRT-PCR. Phosphorylation of histone H3 was analyzed by immunofluorescence (IF). The cell cycle was examined by flow cytometry. The in vivo antitumor effect was validated by the xenograft mouse model.

Results: Cyclin D1 was overexpressed in CRC tissues and cells, and was required for maintaining cell growth, colony formation, and in vivo tumorigenesis. PL decreased the protein level of c-Fos, which eventually reduced the transcriptional activity of AP-1 and the mRNA level of Cyclin D1. Mechanism study showed that PL impaired EGF-induced activation of ERK1/2 and Akt signalings, which resulted in a reduction of c-Fos transcription. Furthermore, PL reduced the half-life of c-Fos and caused the ubiquitination-dependent degradation of c-Fos. Finally, the in vivo antitumor effect of PL on CRC cells was examined using a xenograft mouse model.

Conclusion: Our data indicate that PL is a promising antitumor agent that deserves further study for CRC treatment.

Keywords: Cyclin D1; c-Fos; colorectal cancer; piperlongumine.

Grants and funding

This work was supported by the National Natural Science Foundation of China (No.81904262, No.81401548, and No.81972837) and the Natural Science Foundation of Hunan Province (2018JJ3787, 2018JJ2604, 2019JJ50682).