The Anticancer Activity of the Substituted Pyridone-Annelated Isoindigo (5'-Cl) Involves G0/G1 Cell Cycle Arrest and Inactivation of CDKs in the Promyelocytic Leukemia Cell Line HL-60

Abstract

Background/Aims:The antileukemic potential of isoindigos make them desired candidates for understanding their mechanism of action. We have recently synthesized a novel group of pyridone-annelated isoindigos and identified the derivative 5'-Cl that is cytotoxic to various cancer cell lines. In the present study, we analyzed the effect of this compound on cell cycle of the promyelocytic leukemia cell line HL-60. Methods:HL-60 cells were treated with 5'-Cl and its effect on cell cycle stages were determined by flow cytometry. Expression of cyclins, cyclin dependent kinases (CDKs) and cyclin kinase inhibitors (CKIs) were determined by Western blotting, and activation of CDKs was studied using kinase assays. Results:5'-Cl remarkably arrested cell cycle in HL-60 cells at the G0/G1 phase in a dose and time-dependent manner. Furthermore, 5'-Cl treatment significantly inhibited expression of D-cyclins, CDK2 and CDK4 and suppressed phosphorylation of the retinoblastoma protein Rb, whereas it increased the level of CKI p21. Molecular modelling experiments show that 5'-Cl may compete with ATP for binding to the catalytic subunit of CDK2 and CDK4 that could lead to inhibition of these enzymes. Indeed, 5'-Cl inhibited the kinase activity of CDK2 and CDK4 both in cell free systems and in treated cells. 5'-Cl also inhibited cell cycle progression in several other tumor cell lines. Conclusion:We demonstrate the potent inhibitory effects of 5'-Cl on HL-60 cells could be mediated by arresting cells in the G0/G1 phase.

Furanodienone induces G0/G1 arrest and causes apoptosis via the ROS/MAPKs-mediated caspase-dependent pathway in human colorectal cancer cells: a study in vitro and in vivo

“…CDK 4 and CDK 6 are essential in the progression of G1 phase by forming the CDK 4/6-cyclin D1 complexes, while cyclin E and CDK 2 were necessary in the late of G0/G1 cell phase. 32, 33 CDK inhibitor, p21 Cip1 , has been reported to be related with the G0/G1 phase arrest by inactivation of CDK-cyclin complex (CDK 4/cyclin D and CDK 2/cyclin E). 32 Consistent with results from the previous study, 16 our study reflected that furanodienone increased the proportion of G0/G1 phase, and reduced the cell population in G2/M phase in RKO and HT-29 cells, according to the flow cytometric analysis.…”

A Systems Biology-Based Approach to Uncovering Molecular Mechanisms Underlying Effects of Traditional Chinese Medicine Qingdai in Chronic Myelogenous Leukemia, Involving Integration of Network Pharmacology and Molecular Docking Technology

“…Data in the literature show that Meisoindigo (isoindigo isomer) induced apoptotic cell death and disrupted the progression of K562 cells from the G(1) to G(2) phase [32]. The anticancer activity of the substituted pyridone-annelated isoindigo (5′-Cl) involves G0/G1 cell cycle arrest and inactivation of CDKs in the promyelocytic leukemia cell line HL-60 [33], and Isatin and its derivatives have a very good inhibitory effect in leukemia cells and many kinds of tumor cells [34–37]. However, thus far there have been no published reports showing that N-phenyl-2-naphthylamine is an effective treatment for leukemia and tumors.…”

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“…CDK1, 2, 4 and 6 have been proven to drive cell cycle events. CDK4 and CDK6 are the two interphase cyclin dependent kinases that control cell cycle entry and progression through the G1 phase by forming CDK4/6-cyclin D1 complexes [29,30]. These active complexes have the capacity to phosphorylate and partially inactivate the members of the retinoblastoma (RB) protein family including pRB and p107 [31].…”