Anti-growth Effects of Imatinib and GNF5 via Regulation of Skp2 in Human Hepatocellular Carcinoma Cells

Abstract

BackgroundHuman hepatocellular carcinoma (HCC) is a common liver tumor and the main cause of cancer-related death. Tyrosine kinase inhibitors, such as imatinib and GNF5 which were developed to treat chronic myelogenous leukemia, regulate the progression of various cancers. The aim of this study was to confirm the anti-tumor activity of tyrosine kinase inhibitors through regulation of S-phase kinase-associated protein 2 (Skp2), an important oncogenic factor in various cancer cells, in human hepatocarcinoma SK-HEP1 cells.MethodsCell viability and colony formation assays were conducted to evaluate the effects of imatinib, GNF5 and GNF2 on the growth of SK-HEP1 cells. Using immunoblot analysis, we assessed change of the activation of caspases, PARP, Akt, mitogen-activated protein kinases, and Skp2/p27/p21 pathway by imatinib and GNF5 in SK-HEP1 cells. Using sh-Skp2 HCC cells, the role of Skp2 in the effects of imatinib and GNF5 was evaluated.ResultsImatinib and GNF5 significantly inhibited the growth of SK-HEP1 cells. Treatment of imatinib and GNF5 decreased Skp2 expression and Akt phosphorylation, and increased the expression of p27, p21, and active-caspases in SK-HEP1 cells. In sh-Skp2 HCC cells, cell growth and the expression of Skp2 were inhibited by more than in the mock group treated with imatinib and GNF5.ConclusionsThese results suggest that the anti-growth activity of tyrosine kinase inhibitors may be associated with the regulation of p27/p21 and caspases through Skp2 blockage in HCC cells.

The Effect of BCR-ABL Specific Tyrosine Kinase Inhibitors on the Thioredoxin System in Chronic Myeloid Leukemia

“…It was found using caspase-3 activity assays that the cell death elicited by the TKIs was mediated by apoptosis in all cases, which has been observed by other researchers in CML and other cancer cell lines [53][54][55][56]. Apoptosis can be induced by many cellular processes; however, one of the most common initiators of this process is oxidative stress [57][58][59].…”

Imatinib and GNF-5 Exhibit an Inhibitory Effect on Growth of Hepatocellar Carcinoma Cells by Downregulating S-phase Kinase-associated Protein 2

“…Imatinib has been reported to exhibit potent therapeutic effects in various cancers [ 20 - 22 ]. Our previous study has revealed that imatinib and GNF-5 induce HCC cells apoptosis by inhibiting the expression of Skp2 and p-AKT [ 15 ]. In the present study, we evaluated the effect of imatinib and GNF-5 on HCC cell growth and cell cycle regulation.…”

“…Imatinib (Gleevec, Glivec) is a synthetic tyrosine kinase inhibitor of the breakpoint cluster region-Abelson murine leukemia (Bcr-Abl) fusion gene and is used in the treatment of chronic myeloid leukemia (CML) [ 12 ]. Imatinib has also been used to treat gastrointestinal stromal tumors and various other malignancies [ 13 - 15 ]. GNF-5 is a selective, non-ATP-competitive inhibitor of Bcr-Abl and is used in combination with an ATP-competitive inhibitor, such as imatinib or nilotinib, to enhance antitumor effects in vitro [ 16 ].…”

Allosteric Inhibition of ABL Kinases: Therapeutic Potential in Cancer

“…Preclinically, GNF-2, GNF-5, and ABL-001 have all been effective against solid tumors and/or on tumor cell lines expressing high levels of ABL1/ABL2 (30)(31)(32)(33). In 2009, GNF-2 was shown to inhibit the enzymatic and cellular kinase activities of ABL1, ABL2, and recombinant ABL and to inhibit the proliferation of BCR-ABL1-expressing Ba/F3 fibroblast cells at a potency comparable to that of imatinib (IC 50 ¼ 0.24 mmol/L; ref.…”

“…In 2018, Kim and colleagues found that the more pharmacokinetically active derivative of GNF-2, GNF-5, can inhibit the growth of human hepatocellular carcinoma (SK-HEP1) cells-increasing the expression of tumor suppressors (p27 and p21) alongside markers of apoptosis such as caspases and PARP (33). Further, Malki and colleagues designed several alloxazine derivatives of imatinib that also bind to ABL kinases' allosteric sites (34).…”