Ueshima Eisuke, Nishiofuku Hideyuki, Takaki Haruyuki, Hirata Yutaka, Kodama Hiroshi, Tanaka Toshihiro, Kichikawa Kimihiko, Yamakado Koichiro, Okada Takuya, Sofue Keitaro, Yamaguchi Masato, Sugimoto Koji, Murakami Takamichi
aDepartment of Diagnostic and Interventional Radiology, Kobe University, Kobe, Japan.
bDepartment of Radiology, Nara Medical University, Kashihara, Japan.
Liver Cancer. 2020 Jan;9(1):63-72. doi: 10.1159/000502774. Epub 2019 Oct 16.
The underlying mechanism involved in the recurrence of hepatoma after hepatic arterial embolization (HAE) is not adequately examined. An immunosuppressive cytokine, transforming growth factor β1 (TGF-β1), can lead to tumor progression and is affected by hypoxia in various cancers. The study aimed to assess the effect of HAE on the expression of TGF-β1 in a rat hepatoma model.
Sprague-Dawley rats bearing N1S1 hepatoma cells underwent HAE (HAE group, = 5) or sham treatment (sham group, = 4). The animals were euthanized at 48 h, and liver tissues were harvested. Immunohistochemistry (IHC) and quantitative polymerase chain reaction (qPCR) were performed to compare the expression of TGF-β1 and hypoxia-inducible factor 1α (HIF-1α) between the HAE and sham groups. In vitro experiments with the N1S1 cell line were also performed under normoxic (21% O) or hypoxic (1% O) conditions for 48 h, and the expression of TGF-β1 and HIF-1α was assessed with western blotting and enzyme-linked immunosorbent assay. Statistical data comparisons were performed by Student test.
IHC showed that both the TGF-β1-positive and HIF-1α-positive tumor peripheral areas were larger in the HAE group (6.59 ± 2.49 and 10.26 ± 4.14%; < 0.001, respectively) than in the sham group (0.34 ± 0.41 and 0.40 ± 0.84% respectively). Similarly, qPCR showed that the mRNA expression levels of TGF-β1 and HIF-1α were higher (1.95 ± 0.38-fold and 1.62 ± 0.37-fold; < 0.001 and = 0.002, respectively) in the HAE group than those in the sham group. TGF-β1 expression was suppressed when HIF-1α inhibitors were added ( = 0.001), and HIF-1α expression was upregulated when exogenous TGF-β1 was added ( = 0.033) in N1S1 cells.
HAE enhanced local TGF-β1 expression in a rat hepatoma model. In vitro experiments suggest that HAE-induced hypoxic stress may trigger the interdependent expression of TGF-β1 and HIF-1α.
肝动脉栓塞术（HAE）后肝癌复发所涉及的潜在机制尚未得到充分研究。一种免疫抑制细胞因子，转化生长因子β1（TGF-β1），可导致肿瘤进展，并在各种癌症中受缺氧影响。本研究旨在评估HAE对大鼠肝癌模型中TGF-β1表达的影响。
携带N1S1肝癌细胞的Sprague-Dawley大鼠接受HAE（HAE组，n = 5）或假手术治疗（假手术组，n = 4）。在48小时时对动物实施安乐死，并采集肝脏组织。进行免疫组织化学（IHC）和定量聚合酶链反应（qPCR）以比较HAE组和假手术组之间TGF-β1和缺氧诱导因子1α（HIF-1α）的表达。对N1S1细胞系也在常氧（21% O₂）或缺氧（1% O₂）条件下进行48小时的体外实验，并用蛋白质印迹法和酶联免疫吸附测定法评估TGF-β1和HIF-1α的表达。通过Student t检验进行统计数据比较。
IHC显示，HAE组中TGF-β1阳性和HIF-1α阳性的肿瘤周边区域（分别为6.59±2.49%和10.26±4.14%；P均<0.001）比假手术组（分别为0.34±0.41%和0.40±0.84%）更大。同样，qPCR显示，HAE组中TGF-β1和HIF-1α的mRNA表达水平高于假手术组（分别为1.95±0.38倍和1.62±0.37倍；P<0.001和P = 0.002）。在N1S1细胞中添加HIF-1α抑制剂时TGF-β1表达受到抑制（P = 0.001），添加外源性TGF-β1时HIF-1α表达上调（P = 0.033）。
在大鼠肝癌模型中，HAE增强了局部TGF-β1表达。体外实验表明，HAE诱导的缺氧应激可能触发TGF-β1和HIF-1α的相互依赖表达。
