A phase 1 dose-escalation study of intraperitoneal cisplatin, intravenous/intraperitoneal paclitaxel, bevacizumab, and olaparib for newly diagnosed ovarian cancer

Anti-neoplastic effect of heterophyllin B on ovarian cancer via the regulation of NRF2/HO-1 in vitro and in vivo

BACKGROUND

Heterophyllin B (HB) is a cyclic peptide with anti-neoplastic effect on many cancers. However, its effect and mechanism of action in ovarian cancer cells are still unknown.

PURPOSE

The primary objective of this study was to assess the impact of HB on the proliferation of ovarian cancer (OC) cells and delve into the underlying mechanisms involved.

METHODS

We performed CCK-8 assays, HE staining, KI67 staining, clonogenic formation assays, Annexin V-FITC/PI staining, tumor invasion assays, and migration assays to detect the effects of HB on cell viability, proliferation, apoptosis, migration, and invasion in ovarian cancer cells. Additionally, real-time fluorescent quantitative PCR (qPCR) and Western blotting were utilized for verification. The expression of NF-E2-related factor 2 (NRF2) and heme oxygenase 1 (HMOX1/HO-1) signaling molecules was detected using qPCR and Western blotting. A specific inducer, Hemin, was used to activate HO-1 and Nrf2 overexpression, in order to verify the pharmacological mechanism of HB on ovarian cancer cells. The binding relationship between HB and NRF2 was investigated through molecular docking.

RESULTS

HB treatment inhibited the viability of OC cells, meanwhile it showed suppressive effect on the proliferation, migration, and invasion of OC cells, Meanwhile, HB could promote the apoptosis of tumor cells. For the mechanisms, we found that HB treatment could significantly down-regulate the levels of NRF2/HO-1. Consistent with the results of in vitro experiments, administration of HB significantly delayed tumor growth in OVCAR8 xenografted nude mice, and inhibited the expression of Ki67, Nrf2 and HO-1.

CONCLUSION

This study demonstrated that HB had anti-neoplastic effect on OC by inhibiting Nrf2/HO-1 signaling pathway and may be a potential drug for the treatment of OC.

Dihydrotanshinone I inhibits ovarian tumor growth by activating oxidative stress through Keap1-mediated Nrf2 ubiquitination degradation

Dihydrotanshinone I (DHT), a bioactive compound in Salvia miltiorrhiza, was reported to exhibit cytotoxicity against various malignancies. However, the underlying mechanism on ovarian cancer remains unclear. Here, DHT inhibited cell viability of ovarian cancer HO8910PM, SKOV3, A2780 and ES2 cells. It showed moderate inhibitory effect on ovarian epithelial IOSE80 cells and lower toxicity than chemotherapy drugs. DHT induced apoptosis and G2 cell cycle arrest accompanied by reduced expression of Bcl-2, Caspase-3, and increased Bax. Meanwhile, DHT increased ROS accumulation, decreased mitochondrial membrane potential and activated oxidative stress in HO8910PM and ES2 cells. Mechanistically, DHT inhibited Nrf2 and p62 expression, Nrf2 target genes and enzymes, and Nrf2 nuclear translocation, while increased the expression of Nrf2 inhibitor Keap1. NAC, a ROS scavenger, rescued DHT-induced proliferation inhibition, ROS generation and Nrf2 inhibition. DHT alleviated tBHQ-induced Nrf2 expression and increased its mRNA level. However, the proteasome inhibitor MG132 blocked DHT-induced Nrf2 inhibition, suggesting a post-translational regulation manner. DHT enhanced Nrf2 binding with Keap1, leading to potentiated Nrf2 ubiquitination degradation. Furthermore, Nrf2 and p62 overexpression blocked DHT-induced Nrf2 and p62 inhibition. Consistent with the in vitro results, DHT significantly delayed tumor growth in HO8910PM and ES2 xenograft nude mice, decreased tumor marker HE4 and CA125 levels, reversed the abnormally expressed proteins including Ki67, Nrf2, p62, Keap1, Bcl-2, CyclinB1, Cdc-2, and antioxidant enzymes SOD, CAT in vivo. Serum from DHT-treated mice also inhibited cell growth in vitro. Taken together, DHT exhibits anti-ovarian tumor effect by activating oxidative stress through ubiquitination-mediated Nrf2 degradation. Our findings implicate a potential application of DHT for ovarian cancer therapy.