Ethyl Acetate Extract of Selaginella doederleinii Hieron Induces Cell Autophagic Death and Apoptosis in Colorectal Cancer via PI3K-Akt-mTOR and AMPKα-Signaling Pathways

Shaoguang Li; Xuewen Wang; Gang Wang; Peiying Shi; Shilan Lin; Dafen Xu; Bing Chen; Ailin Liu; Liying Huang; Xinhua Lin; Hong Yao

doi:10.3389/fphar.2020.565090

Ethyl Acetate Extract of Selaginella doederleinii Hieron Induces Cell Autophagic Death and Apoptosis in Colorectal Cancer via PI3K-Akt-mTOR and AMPKα-Signaling Pathways

Front Pharmacol. 2020 Oct 19:11:565090. doi: 10.3389/fphar.2020.565090. eCollection 2020.

Authors

Shaoguang Li^{1

2

3}, Xuewen Wang^{1

2

3}, Gang Wang^{1

2

3}, Peiying Shi⁴, Shilan Lin^{1

2

3}, Dafen Xu^{1

2

3}, Bing Chen^{1

2

3}, Ailin Liu^{1

2

3}, Liying Huang¹, Xinhua Lin^{1

2

3}, Hong Yao^{1

2

3

5}

Affiliations

¹ Department of Pharmaceutical Analysis, School of Pharmacy, Fujian Medical University, Fuzhou, China.
² Higher Educational Key Laboratory for Nano Biomedical Technology of Fujian Province, Fujian Medical University, Fuzhou, China.
³ Nano Medical Technology Research Institute, Fujian Medical University, Fuzhou, China.
⁴ Department of Traditional Chinese Medicine Resource and Bee Products, Bee Science College, Fujian Agriculture and Forestry University, Fuzhou, China.
⁵ Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, Fujian Medical University, Fuzhou, China.

Abstract

Colorectal cancer is one type of cancer with high incidence rate and high mortality worldwide. Thus, developing new chemotherapeutic drugs is important. The Selaginella doederleinii Hieron ethyl acetate (SDEA) extract showed good anti-colon cancer effect in vitro and in vivo, but its mechanism is unclear. This study aimed to further reveal the anti-colon cancer effect of SDEA and its possible mechanism. The effects on cell viability, apoptosis, autophagy, and cell cycle in colorectal cells (HT29 and HCT116) were studied using MTT assay, fluorescence microscopy, transmission electron microscopy, and flow cytometry. The mechanisms were further studied using cell transfection, Western blot, and real-time quantitative polymerase chain reaction assay. The effect of xenotransplantation in vivo was observed using immunohistochemistry. Results showed that SDEA inhibited cell proliferation and induced cell morphological changes, cell cycle arrest, autophagy, and apoptosis. It also induced loss of mitochondrial membrane potential, increased the autophagic flux, raised the ratio of Bax/Bcl-2, activated caspases, and inhibited PI3K-Akt-mTOR signaling pathways. Furthermore, SDEA inhibited the growth of xenograft tumors in a dose-dependent manner. Immunohistochemistry analysis confirmed the alteration of autophagy- and apoptosis-related proteins and immunohistochemical microvascular density in xenografts, which were consistent with the results in vitro. Therefore, SDEA is important for developing candidate drugs against colorectal cancers.

Keywords: Selaginella doederleinii Hieron ethyl acetate; antitumor mechanism; apoptosis; autophagy; colorectal carcinoma.