Novel smac mimetic APG-1387 elicits ovarian cancer cell killing through TNF-alpha, Ripoptosome and autophagy mediated cell death pathway

Abstract

BackgroundOvarian cancer is a deadly disease. Inhibitors of apoptosis proteins (IAPs) are key regulators of apoptosis and are frequently dysregulated in ovarian cancer. Overexpression of IAPs proteins has been correlated with tumorigenesis, treatment resistance and poor prognosis. Reinstalling functional cell death machinery by pharmacological inhibition of IAPs proteins may represent an attractive therapeutic strategy for treatment of ovarian cancer.MethodsCCK-8 and colony formation assay was performed to examine cytotoxic activity. Apoptosis was analyzed by fluorescence microscopy, flow cytometry and TUNEL assay. Elisa assay was used to determine TNFα protein. Caspase activity assay was used for caspase activation evaluation. Immunoprecipitation and siRNA interference were carried out for functional analysis. Western blotting analysis were carried out to test protein expression. Ovarian cancer cell xenograft nude mice model was used for in vivo efficacy evaluation.ResultsAPG-1387 demonstrated potent inhibitory effect on ovarian cancer cell growth and clonogenic cell survival. APG-1387 induced RIP1- and TNFα-dependent apoptotic cell death in ovarian cancer through downregulation of IAPs proteins and induction of caspase-8/FADD/RIP1 complex, which drives caspase-8 activation. NF-κB signaling pathway was activated upon APG-1387 treatment and RIP1 contributed to NF-κB activation. APG-1387 induced cytoprotective autophagy while triggering apoptosis in ovarian cancer cells and inhibition of autophagy enhanced APG-1387-induced apoptotic cell death. APG-1387 exhibited potent antitumor activity against established human ovarian cancer xenografts.ConclusionsOur results demonstrate that APG-1387 targets IAPs proteins to potently elicit apoptotic cell death in vitro and in vivo, and provide mechanistic and applicable rationale for future clinical evaluation of APG-1387 in ovarian cancer.

The SMAC Mimetic APG-1387 Sensitizes Immune-Mediated Cell Apoptosis in Hepatocellular Carcinoma

“…In the present study, the bivalent SMAC mimetic APG-1387 was able to induce almost complete reduction of cIAP1 and cIAP2, and suppressed XIAP to some extent in HCC cell line HepG2 and HCCLM3. However, unlike the significant anti-tumor effects of APG-1387 on ovarian cancer ( Li et al, 2018 ), nasopharyngeal carcinoma ( Li et al, 2016 ) and PLC/PRF/5 cells ( Pan et al, 2018 ), APG-1387 treatment alone, only showed limited inhibitory effects on HCC cell lines HepG2, HCCLM3 and Huh7, suggesting that HCC is more resistant to the SMAC mimetic than ovarian cancer or nasopharyngeal carcinoma.…”

“…Currently, several SMAC mimetics have been designed and are undergoing evaluation in early clinical trials as potential cancer therapeutic agents ( Fulda and Vucic, 2012 ; Fulda, 2015a ). APG-1387 is a novel bivalent SMAC mimetic that has been shown to have significant antitumor activities in ovarian cancer ( Li et al, 2018 ), nasopharyngeal carcinoma ( Li et al, 2016 ) and HBV-positive HCC cell line PLC/PRF/5 ( Pan et al, 2018 ), but has yet to be evaluated in other HCC cell types that resistant to its monotherapy. In this study, we examined the expression of IAPs in human liver tumor tissues and investigated the combinational anti-tumor potential of APG-1387 with cytokines or immune cells in HCC cell lines that resistant to APG-1387 monotherapy, and in a mouse xenograft model of HCC.…”

Potency and Selectivity of SMAC/DIABLO Mimetics in Solid Tumor Therapy

“…Earlier studies showed that, in apoptosis-resistant leukemia cells, SMs can potentiate TNF-induced necroptosis by enhancing the formation of the necrosome complex [84,115]. Subsequently, SM treatment induced massive cell death and led to regression of tumors in solid tumors [116,117]. These findings indicated that SMs can combine with death receptors to trigger apoptotic cell death.…”

Future Therapeutic Directions for Smac-Mimetics

“…APG-1387 (Ascentage Pharma) has shown anti-cancer effects as a single agent in vitro and in vivo in nasopharyngeal carcinoma cells and in ovarian cancer cells [100][101][102]. APG-1387 is currently in dose-escalation Phase I/II clinical trials to determine safety, tolerability, pharmacokinetics and anti-cancer activity in patients with advanced solid tumors or hematological malignancies (Table 2) (NCT03386526, ACTRN12614000268640 and CTR20150161) [103,104].…”