Cytotoxicity, Oxidative Stress, Cell Cycle Arrest, and Mitochondrial Apoptosis after Combined Treatment of Hepatocarcinoma Cells with Maleic Anhydride Derivatives and Quercetin

Abstract

The inflammatory condition of malignant tumors continually exposes cancer cells to reactive oxygen species, an oxidizing condition that leads to the activation of the antioxidant defense system. A similar activation occurs with glutathione production. This oxidant condition enables tumor cells to maintain the energy required for growth, proliferation, and evasion of cell death. The objective of the present study was to determine the effect on hepatocellular carcinoma cells of a combination treatment with maleic anhydride derivatives (prooxidants) and quercetin (an antioxidant). The results show that the combination of a prooxidant/antioxidant had a cytotoxic effect on HuH7 and HepG2 liver cancer cells, but not on either of two normal human epithelial cell lines or on primary hepatocytes. The combination treatment triggered apoptosis in hepatocellular carcinoma cells by activating the intrinsic pathway and causing S phase arrest during cell cycle progression. There is also clear evidence of a modification in cytoskeletal actin and nucleus morphology at 24 and 48 h posttreatment. Thus, the current data suggest that the combination of two anticarcinogenic drugs, a prooxidant followed by an antioxidant, can be further explored for antitumor potential as a new treatment strategy.

Antitumor Effects of Quercetin in Hepatocarcinoma In Vitro and In Vivo Models: A Systematic Review

“…Jeon et al reported an increase in p53 levels and a decrease in cyclin A and checkpoint kinase 1 (CHK1) expression in HepG2 cells after quercetin treatment [25], while this drug downregulated p53 and enhanced G0/G1 and G2/M populations in HepG2 and HuH7 HCC lines [51]. Augmented levels of p21 and p27, cell cycle inhibitors, and cyclin D1 reduction were observed in another study with HepG2 cells [33] and it has been also shown that quercetin promoted G0/G1-phase arrest [49,52,53] through upregulating p16, p21 and p53 [53]. Conversely, a cell cycle arrest at G2/M phase has been described as a quercetin effect against HCC cell proliferation in HepG2 [30] and LM3 liver cancer lines [22].…”

“…Quercetin antitumor effects have been described in different cancer types, including HCC [1]. In 25 of the articles included in the present review, quercetin efficacy as single treatment was evaluated employing different HCC study models [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]46,48,49,[51][52][53][54]57]. Antiproliferative effect of this flavonoid alone has been demonstrated in several researches with in vitro models [22][23][24][25][26][27][30][31][32][33]35,38,46,48,49,[51][52][53][54], highlighting the HepG2 cell line as the most used in 21 of the 25 articles [24,25,<...>…”

“…Otherwise, though cell cycle regulation is a common mechanism found to be altered in HCC cells, only eight publications have evaluated the effects of quercetin in this process, showing contradictory results [22,25,30,33,49,[51][52][53]. Jeon et al reported an increase in p53 levels and a decrease in cyclin A and checkpoint kinase 1 (CHK1) expression in HepG2 cells after quercetin treatment [25], while this drug downregulated p53 and enhanced G0/G1 and G2/M populations in HepG2 and HuH7 HCC lines [51].…”

“…Although a great number of antitumor properties of quercetin have been established in HCC treatment-mainly in cell line but also in animal models-some researchers have focused on searching for synergistic combinations with this flavonoid with the aim of improving its effectiveness against liver cancer [45][46][47][48][49][50][51][52][53][54]. Enhanced properties with the well-stablished first-line drug sorafenib was demonstrated in several HCC cell lines (HepG2, HuH7 and Hep3B2.1-7) by reducing its half-maximal inhibitory concentration (IC50) [51] and improving its tumor suppression activity [46].…”

“…Enhanced properties with the well-stablished first-line drug sorafenib was demonstrated in several HCC cell lines (HepG2, HuH7 and Hep3B2.1-7) by reducing its half-maximal inhibitory concentration (IC50) [51] and improving its tumor suppression activity [46]. Similarly, quercetin was able to raise antiproliferative action of several molecules, such as interferon-α (IFN-α) [48]; an oncolytic adenovirus expressing tumor necrosis factor-related apoptosis inducing ligand (ZD55-TRAIL) [47]; two derivatives of the organic compound maleic anhydride (3 5 -dimaleamylbenzoic acid and 3 5 -dimaleimylbenzoic acid) [49]; the chemotherapeutic drugs celecoxib [50], 5-fluorouracil (5-FU) [52] and cisplatin [53]; and the CDK inhibitor roscovitine [54]. Alterations in cell morphology of Hep3B and HepG2 HCC lines were described as results of quercetin combination with the aforementioned roscovitine [54].…”