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

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 anticolon 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 apoptosisrelated 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.

Growth Factors, PI3K/AKT/mTOR and MAPK Signaling Pathways in Colorectal Cancer Pathogenesis: Where Are We Now?

“…Future preclinical and clinical studies must be carried out [ 162 ]. The study conducted by Li S et al evaluated the effect of the extract Selaginella doederleinii Hieron ethyl acetate (SDEA) in vitro and in vivo [ 178 ]. Using HT29 and HCT116 cell lines, the anti-tumoral effect of SDEA was manifested by cell morphological changes, cell cycle arrest, autophagy, and apoptosis [ 178 ].…”

“…The study conducted by Li S et al evaluated the effect of the extract Selaginella doederleinii Hieron ethyl acetate (SDEA) in vitro and in vivo [ 178 ]. Using HT29 and HCT116 cell lines, the anti-tumoral effect of SDEA was manifested by cell morphological changes, cell cycle arrest, autophagy, and apoptosis [ 178 ]. Moreover, the SDEA extract may induce the loss of the mitochondrial membrane potential, increases the autophagic flux, and will inhibit the PI3K/AKT/mTOR signaling pathways [ 178 ].…”

“…Using HT29 and HCT116 cell lines, the anti-tumoral effect of SDEA was manifested by cell morphological changes, cell cycle arrest, autophagy, and apoptosis [ 178 ]. Moreover, the SDEA extract may induce the loss of the mitochondrial membrane potential, increases the autophagic flux, and will inhibit the PI3K/AKT/mTOR signaling pathways [ 178 ]. Therefore, in xenograft tumors, SDEA inhibits the growth in a dose-dependent manner [ 178 ].…”

“…Moreover, the SDEA extract may induce the loss of the mitochondrial membrane potential, increases the autophagic flux, and will inhibit the PI3K/AKT/mTOR signaling pathways [ 178 ]. Therefore, in xenograft tumors, SDEA inhibits the growth in a dose-dependent manner [ 178 ]. The experimental studies conducted by Han YH and co-workers, performed on cell lines, explored the inhibitory effect of betulin in mCRC [ 179 ].…”

Pharmacokinetics, Tissue Distribution, and Human Serum Albumin Binding Properties of Delicaflavone, a Novel Anti-Tumor Candidate

“…Delicaflavone (DF), a rarely occurring biflavonoid, is an active ingredient isolated from Selaginella doederleinii Hieron, a traditional Chinese medicine used for health promotion and treatment of various cancers ( Liu et al, 2011 ; Li et al, 2020 ). Modern pharmacological studies have demonstrated that DF induces reactive oxygen species (ROS)-mediated apoptosis and cell cycle arrest via the PI3K/AKT/mTOR and Ras/MEK/Erk signaling pathways, which results in autophagic cell death via the Akt/mTOR/p70S6K signaling pathway ( Sui et al, 2017 ; Yao et al, 2020 ).…”