Pirarubicin inhibits multidrug-resistant osteosarcoma cell proliferation through induction of G2/M phase cell cycle arrest

Abstract

Aim: Pirarubicin (THP) is recently found to be effective in treating patients with advanced, relapsed or recurrent high-grade osteosarcoma. In this study, the effects of THP on the multidrug-resistant (MDR) osteosarcoma cells were assessed, and the underlying mechanisms for the disruption of cell cycle kinetics by THP were explored. Methods: Human osteosarcoma cell line MG63 and human MDR osteosarcoma cell line MG63/DOX were tested. The cytotoxicity of drugs was examined using a cell proliferation assay with the Cell Counting Kit-8 (CCK-8). The distribution of cells across the cell cycle was determined with flow cytometry. The expression of cell cycle-regulated genes cyclin B1 and Cdc2 (CDK1), and the phosphorylated Cdc2 and Cdc25C was examined using Western blot analyses. Results: MG63/DOX cells were highly resistant to doxorubicin (ADM) and gemcitabine (GEM), but were sensitive or lowly resistant to THP, methotrexate (MTX) and cisplatin (DDP). Treatment of MG63/DOX cells with THP (200-1000 ng/mL) inhibited the cell proliferation in time-and concentration-dependent manners. THP (50-500 ng/mL) induced MG63/DOX cell cycle arrest at the G 2 /M phase in time-and concentration-dependent manners. Furthermore, the treatment of MG63/DOX cells with THP (200-1000 ng/mL) downregulated cyclin B1 expression, and decreased the phosphorylated Cdc2 at Thr 161 . Conversely, the treatment increased the phosphorylated Cdc2 at Thr 14 /Tyr 15 and Cdc25C at Ser 216 , which led to a decrease in Cdc2-cyclin B1 activity. Conclusion: The cytotoxicity of THP to MG63/DOX cells may be in part due to its ability to arrest cell cycle progression at the G 2 /M phase, which supports the use of THP for managing patients with MDR osteosarcoma.

BF12, a Novel Benzofuran, Exhibits Antitumor Activity by Inhibiting Microtubules and the PI3K/Akt/mTOR Signaling Pathway in Human Cervical Cancer Cells

“…The cdc25 can eliminate the phosphate of cdc2 at Thrl4/Tyrl5, induce the activation of cdc2/cyclin Bl complex, and promote the transition from G2 phase to M phase . Loss of the cdc2/cyclin Bl complex can block cells at G2/M phase, thereby blocking mitosis . In our study, the expressions of cdc2, p‐cdc2 (Tyr15), and cyclin B1 after BF12 exposure were significantly increased, as shown in Figure a – 3d .…”

Lentinan mitigates therarubicin-induced myelosuppression by activating bone marrow-derived macrophages in an MAPK/NF-κB-dependent manner

“…This agent inserts into the DNA and interacts with topoisomerase II, thereby blocking DNA replication and arresting tumour cells in the G2 phase. As a consequence, the tumour cells cannot enter the cell division phase, which leads to cell death (20). THP inhibits tumour cells with abnormal proliferation and neutrophils with rapid cell division.…”

“…LNT is a β-D-glucan extracted from shiitake mushrooms (Lentinus edodes). A role for LNT in regulating the immune system has been implicated both in vivo and in vitro by several studies (13)(14)(15)(16)(17)(18)(19)(20)(21)(22). Moreover, LNT has antitumour (23), antioxidation (24) and DNA damage repair activities (12).…”

Telekin suppresses human hepatocellular carcinoma cells in vitro by inducing G2/M phase arrest via the p38 MAPK signaling pathway

“…Cell cycle progression is regulated by a group of proteins that are expressed at cyclical levels during the cell cycle. These proteins, known as cyclin-dependent kinase complexes, are composed of cyclin-dependent kinases (CDKs) and cofactors such as cyclins [1] . Cdc2, also called maturation-promoting factor, is one of these factors [2] .…”

“…These findings suggest that Cdc2 is an important player in cell cycle regulation. Cdc2 can also in turn be inactivated by phosphorylation at Tyr15 and Thr14 by Wee1/Myt, leading to cell cycle arrest [1] . However, this phosphorylation status can be regulated by Cdc25, which has been demonstrated to play an essential role in cell proliferation, apoptosis and tumorigenesis [5,6] .…”