Acetyl-macrocalin B, anent-kaurane diterpenoid, initiates apoptosis through the ROS-p38-caspase 9-dependent pathway and induces G2/M phase arrest via the Chk1/2-Cdc25C-Cdc2/cyclin B axis in non-small cell lung cancer

Abstract

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide, and novel effective drugs against NSCLC are urgently needed. Isodon species are rich in ent-kaurane diterpenoids that have been reported to have antitumor bioactivity. Acetyl-macrocalin B (A-macB) is a novel ent-kaurane diterpenoid isolated from Isodon silvatica, and its antitumor efficacy against NSCLC and the underlying mechanisms were scrutinized in depth. The viability of cells treated with A-macB was detected by CCK-8 and colony formation assays. Apoptosis and cell cycle distribution were analyzed by flow cytometry. The mechanisms were investigated by detecting ROS and performing western blotting and verification experiments with specific inhibitors. The in vivo effect of A-macB was explored in a nude mouse xenograft model. A-macB effectively inhibited H1299 and A549 cell viability, triggered apoptosis and delayed cells in the G2/M phase. A-macB induced cellular ROS production and then activated the p38 MAPK-mediated, caspase 9-dependent apoptotic pathway. Both the ROS scavenger NAC and the specific p38 inhibitor SB203580 inactivated the function of p38 induced by A-macB, thus preventing cells from apoptosis. A-macB activated the Chk1/2-Cdc25C-Cdc2/cyclin B1 axis to induce G2/M phase arrest. AZD7762 abrogated the function of Chk1/2, abolished the G2/M delay and enhanced the cytotoxicity of A-macB. Moreover, A-macB efficiently suppressed tumor growth in a mouse xenograft model without noticeable toxicity to normal tissues. Having both efficacy and relative safety, A-macB is a potential lead compound that is worthy of further exploration for development as an anticancer agent.

Natural product corynoline suppresses melanoma cell growth through inducing oxidative stress

“…To further confirm the inhibitory effect of corynoline on melanoma cells, colony formation assay, a well‐established method for characterizing capability of cell proliferation in vitro was conducted (Werner‐Klein et al, 2018). Compared with B16F10 cell line, A375 exhibits a weaker colony formation ability as reflected by lesser colonies (Passeron et al, 2009; J. N. Wang et al, 2018). Notably, we observed that the number and size of the cell colonies in corynoline‐treated group were remarkably decreased, when compared with that of control group (Figure 1d).…”

Checkpoint kinase inhibitor AZD7762 enhance cisplatin-induced apoptosis in osteosarcoma cells

“…AZD7762 is a novel ATP-competitive cell cycle detection point kinase inhibitor, which has a strong inhibiting effect on Chk1. AZD7762 could inhibit phosphorylation of Cdc25C peptide by reversible binding to the ATP binding site of Chk1 [25]. Moreover, AZD7762 is 100 times more selective binding to Chk1 than the traditional Chk inhibitor UCN-01.…”

3′‐Desmethylarctigenin induces G2/M cell cycle arrest and apoptosis through reactive oxygen species generation in hepatocarcinoma cells

“…One of the factors that contribute towards checkpoint initiation and cell cycle arrest in G2/M is the activation of chk1 or/and chk2 kinase (Manic, Obrist, Sistigu, & Vitale, ; Reinhardt & Yaffe, ), and it has been shown that these two kinases are involved in G2/M arrests via Chk1/2–Cdc25C–Cdc2–cyclin B1 pathway in human cell lines (Wang et al, ). We therefore investigated the potential role of chk1 and chk2 in 3′‐DMAG‐induced G2/M halt.…”