BACKGROUND Hepatocellular carcinoma (HCC) is one of the most common malignancies, with an increasing incidence. Despite the fact that systematic chemotherapy with a doxorubicin provides only marginal improvements in survival of the HCC patients, the doxorubicin is being used in transarterial therapies or combined with the target drug - sorafenib. The aim of the study was to evaluate the effect of natural flavonoids on the cytotoxicity of the doxorubicin against human hepatocellular carcinoma cell line HepG2. METHODS The effect of apigenin and its glycosides - cosmosiin, rhoifolin; baicalein and its glycosides - baicalin as well as hesperetin and its glycosides - hesperidin on glycolytic genes expression of HepG2 cell line, morphology and cells' viability at the presence of doxorubicin have been tested. In an attempt to elucidate the mechanism of observed results, the fluorogenic probe for reactive oxygen species (ROS), the DNA oxidative damage, the lipid peroxidation and the double strand breaks were evaluated. To assess impact on the glycolysis pathway, the mRNA expression for a hexokinase 2 (HK2) and a lactate dehydrogenase A (LDHA) enzymes were measured. The results were analysed statistically with the one-way analysis of variance (ANOVA) and post hoc multiple comparisons. RESULTS The apigenin and the hesperidin revealed the strongest effect on the toxicity of doxorubicin. Both flavonoids simultaneously changed the expression of the glycolytic pathway genes - HK2 and LDHA, which play a key role in the Warburg effect. Although separate treatment with doxorubicin, apigenin and hesperidin led to a significant oxidative DNA damage and double strand breaks, simultaneous administration of doxorubicin and apigenin or hesperidin abolished these damage with the simultaneous increase in the doxorubicin toxicity. CONCLUSION The obtained results indicate the existence of a very effective cytotoxic mechanism in the HepG2 cells of the combined effect of doxorubicin and apigenin (or hesperidin), not related to the oxidative stress. To explain this synergy mechanism, further research is needed, The observed intensification of the cytotoxic effect of doxorubicin by this flavonoids may be a promising direction of the research on the therapy of hepatocellular carcinoma, especially in a chemoembolization.

中文翻译：

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芹菜素和橙皮苷增强阿霉素对 HepG2 细胞的毒性作用。

背景技术肝细胞癌（HCC）是最常见的恶性肿瘤之一，其发病率不断增加。尽管阿霉素系统化疗只能略微改善 HCC 患者的生存率，但阿霉素仍用于经动脉治疗或与目标药物索拉非尼联合使用。本研究的目的是评估天然黄酮类化合物对阿霉素对人肝癌细胞系 HepG2 细胞毒性的影响。方法 芹菜素及其苷类——大波斯菊苷、大黄果苷的作用；测试了黄芩素及其苷-黄芩苷以及橙皮素及其苷-橙皮苷对HepG2细胞系糖酵解基因表达、形态和细胞在阿霉素存在下的活力的影响。为了阐明观察到的结果的机制，对活性氧 (ROS) 的荧光探针、DNA 氧化损伤、脂质过氧化和双链断裂进行了评估。为了评估对糖酵解途径的影响，测量了己糖激酶 2 (HK2) 和乳酸脱氢酶 A (LDHA) 的 mRNA 表达。通过单因素方差分析（ANOVA）和事后多重比较对结果进行统计分析。结果芹菜素和橙皮苷对阿霉素的毒性作用最强。两种黄酮类化合物同时改变了糖酵解途径基因 HK2 和 LDHA 的表达，这些基因在 Warburg 效应中发挥着关键作用。尽管单独使用阿霉素、芹菜素和橙皮苷治疗会导致显着的氧化DNA损伤和双链断裂，但同时给予阿霉素和芹菜素或橙皮苷消除了这些损伤，同时阿霉素毒性增加。结论所获得的结果表明阿霉素和芹菜素（或橙皮苷）的联合作用在HepG2细胞中存在非常有效的细胞毒机制，与氧化应激无关。为了解释这种协同机制，还需要进一步的研究。观察到的这种黄酮类化合物增强阿霉素的细胞毒作用可能是肝细胞癌治疗，特别是化疗栓塞治疗研究的一个有前途的方向。