Targeting Akt by SC66 triggers GSK-3β mediated apoptosis in colon cancer therapy

Abstract

Background Colon cancer is one of the three common malignant tumors, with lower 5 years survival rate. Akt is an important therapeutic target, while SC66 is a novel allosteric AKT inhibitor, which enhances the therapeutic effect in several types of cancer. However, the molecular mechanisms of targeting AKT by SC66 during colon cancer therapy are not well understood. Methods The biological role of GSK-3β in colon cancer growth suppression induced by SC66 was detected in vitro and in vivo. Hoechst 33342 and crystal violet staining were used to determine whether targeting AKT affected apoptosis and cell proliferation. The CCK8 assay was utilized to analyze cell viability. The expression levels of Akt, GSK-3β, Bax, Bcl-xL, p53 and PUMA were measured by immune blotting. Xenograft mouse model was established to study the antitumor effect of SC66 in vivo. Results Our results show that SC66 induced significantly colon cancer cell apoptosis, accompanied with Akt inactivation. After AKT inhibition, activated GSK-3β interacted with Bax directly, leading to Bax oligomerization and activation. Knocking down GSK-3β abrogated SC66-triggered Bax activation and apoptosis, which was enhanced by over-expressed GSK-3β. In addition, the expression level of Bcl-xL was down-regulated while p53 had no function during SC66-induced apoptosis. Furthermore, colon cancer growth was suppressed by SC66 therapy in vivo. Conclusion Taken together, these data indicated that the novel small molecule AKT inhibitor SC66 shows visible antitumor effects via the AKT/GSK-3β/Bax axis in vitro and in vivo. Our results provide a rational basis for the development of targeting-GSK-3β, which may serve as a potential biomarker and yield meaningful benefits for colon cancer patients in the future.

Design and Synthesis of New Benzo[d]oxazole-Based Derivatives and Their Neuroprotective Effects on β-Amyloid-Induced PC12 Cells

“…GSK-3β is one of the primary tau kinases and its activity requires serine dephosphorylation [ 28 ], the presence of mutual regulatory systems between kinases including GSK-3β or Akt and phosphatases such as PP2A [ 29 ]. Akt regulated the phosphorylation of GSK-3β, thereby participating in tau protein hyperphosphorylation and cell apoptosis [ 30 ]. Compound 5c significantly inhibited the expression of p-GSK-3β/GSK-3β ( p < 0.001, Figure 3 E,G), so did the hyperphosphorylation of tau protein at the Thr181-p-tau, Thr205-p-tau and Ser396-p-tau sites ( p < 0.01 or p < 0.001, Figure 3 A–D) and increased the ratio of p-Akt/Akt ( p < 0.001, Figure 3 E,F) together with donepezil.…”

Anticancer property of Hemp Bioactive Peptides in Hep3B liver cancer cells through Akt/GSK3β/β‐catenin signaling pathway

“…It has also been reported that prodigiosin inhibits the phosphorylation of GSK‐3β, restraining β‐catenin‐mediated Wnt activation and subsequent transcriptional activation of prosurvival genes, such as cyclin D1, slowing tumor progression in a breast cancer tumor model mice (Wang et al., 2016). Phosphorylated Akt has the ability to phosphorylate GSK‐3β as a key molecule in this process, which in turn inhibits cell survival via β‐catenin phosphorylation and induction of apoptosis (Liu et al., 2019). The β‐catenin pathway is abnormally activated in liver cancer and has been implicated in tumor formation, progression, metastasis, and drug resistance (Vilchez et al., 2016).…”

AKT Inhibitor SC66 Inhibits Proliferation and Induces Apoptosis in Human Glioblastoma Through Down-Regulating AKT/β-Catenin Pathway

“…Previous study had demonstrated that SC66 could significantly induced apoptosis by accompanied by inactivating AKT. The expression of Bcl-XL was dramatically decreased when colon cancer cells were treated with SC66 ( Liu et al., 2019 ). Consistent with these findings, we found that SC66 treatment induced U87 and U251 cells apoptosis in a dose-dependent manner detected by flow cytometry.…”

“…We further investigated the effect of SC66 on pathway through which SC66 regulated proliferation, EMT and apoptosis of glioma cells. SC66 inhibited colon cancer cell proliferation through AKT/GSK-3β/Bax axis in vivo and in vitro ( Liu et al., 2019 ). Meanwhile, SC66 induced changes in cytoskeletal organization and ROS production, resulting in phosphorylated AKT level was notably decreased, and demonstrated that SC66 remarkably inhibit tumor growth via AKT/mTOR/β-catenin pathway in hepatocellular carcinoma ( Cusimano et al., 2015 ).…”

“…SC66 combined with cisplatin showed a more effective suppression of tumor growth in the xenograft model of ovarian cancer mice ( Wu et al., 2019 ). In addition, SC66 suppressed colon cancer cell proliferation and induced apoptosis ( Liu et al., 2019 ). These studies indicated that SC66 might be a potential antitumor drug.…”