Hepatocellular carcinoma (HCC) remains a major global health problem with high incidence and mortality. Diagnosis of HCC at late stages and tumour heterogeneity in patients with different genetic profiles are known factors that complicate the disease treatment. HCC therapy becomes even more challenging in patients with drug resistance such as resistance to sorafenib, which is a common drug used in HCC patients. Sorafenib resistance can further aggravate HCC by regulating various oncogenic pathways such as autophagy and nuclear factor-kappa Beta (NF-ĸβ) signalling. Sirtuin 1 (SIRT1), is a nicotinamide adenosine dinucleotide (NAD)-dependent histone deacetylases that regulates various metabolic and oncogenic events such as cell survival, apoptosis, autophagy, tumourigenesis, metastasis and drug resistance in various cancers, but its role in HCC, particularly in sorafenib resistance is underexplored. In this study, we generated sorafenib-resistant HepG2 and Huh-7 liver cancer cell models to investigate the role of SIRT1 and its effect on autophagy and nuclear factor-kappa Beta (NF-ĸβ) signalling pathways. Western blot analysis showed increased SIRT1, altered autophagy pathway and activated NF-ĸβ signalling in sorafenib-resistant cells. SIRT1-silenced HCC cells demonstrated down-regulated autophagy in both parental and chemoresistant cells. This may occur through the deacetylation of key autophagy molecules such as FOXO3, beclin 1, ATGs and LC3 by SIRT1, highlighting the role of SIRT1 in autophagy induction. Silencing of SIRT1 also resulted in activated NF-ĸβ signalling. This is because SIRT1 failed to deacetylate p65 subunit of NF-κB, translocate the NF-κB from nucleus to cytoplasm, and suppress NF-κB activity due to the silencing. Hence, the NF-κB transcriptional activity was restored. These findings summarize the role of SIRT1 in autophagy/NF-ĸβ regulatory axis, with a similar trend observed in both parental and sorafenib-resistant cells. The present work promotes a better understanding of the role of SIRT1 in autophagy and NF-ĸβ signalling in HCC and sorafenib-resistant HCC. As some key proteins in these pathways are potential therapeutic targets, a better understanding of SIRT1/autophagy/NF-ĸβ axis could further improve the therapeutic strategies against HCC.

肝细胞癌（HCC）仍然是全球主要的健康问题，发病率和死亡率很高。晚期 HCC 的诊断和具有不同基因谱的患者的肿瘤异质性是使疾病治疗复杂化的已知因素。对于具有耐药性（例如对索拉非尼（HCC 患者常用药物）耐药）的患者，HCC 治疗变得更具挑战性。索拉非尼耐药可通过调节自噬和核因子-κβ (NF-β) 信号等多种致癌途径进一步加重 HCC。Sirtuin 1 (SIRT1) 是一种烟酰胺腺苷二核苷酸 (NAD) 依赖性组蛋白脱乙酰酶，可调节各种代谢和致癌事件，如各种癌症中的细胞存活、凋亡、自噬、肿瘤发生、转移和耐药性，但其在 HCC 中的作用，特别是索拉非尼的耐药性尚未得到充分研究。在本研究中，我们构建了索拉非尼耐药的 HepG2 和 Huh-7 肝癌细胞模型，以研究 SIRT1 的作用及其对自噬和核因子-κ Beta (NF-β) 信号通路的影响。蛋白质印迹分析显示索拉非尼耐药细胞中 SIRT1 增加、自噬途径改变并激活 NF-κβ 信号传导。SIRT1 沉默的 HCC 细胞在亲代细胞和化疗耐药细胞中均表现出下调的自噬。这可能是通过 SIRT1 对 FOXO3、beclin 1、ATGs 和 LC3 等关键自噬分子进行脱乙酰化来实现的，这凸显了 SIRT1 在自噬诱导中的作用。SIRT1 沉默也会导致 NF-κβ 信号传导激活。这是因为SIRT1未能使NF-κB的p65亚基脱乙酰化，将NF-κB从细胞核易位至细胞质，并因沉默而抑制NF-κB活性。因此，NF-κB转录活性得以恢复。这些发现总结了 SIRT1 在自噬/NF-κβ 调节轴中的作用，在亲代细胞和索拉非尼耐药细胞中观察到类似的趋势。目前的工作有助于更好地了解 SIRT1 在 HCC 和索拉非尼耐药 HCC 中自噬和 NF-κβ 信号传导中的作用。由于这些通路中的一些关键蛋白是潜在的治疗靶点，更好地了解 SIRT1/自噬/NF-κβ 轴可以进一步改善 HCC 的治疗策略。