Targeting the Epigenetic Non-Coding RNA MALAT1/Wnt Signaling Axis as a Therapeutic Approach to Suppress Stemness and Metastasis in Hepatocellular Carcinoma
Targeting the Epigenetic Non-Coding RNA MALAT1/Wnt Signaling Axis as a Therapeutic Approach to Suppress Stemness and Metastasis in Hepatocellular Carcinoma
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DOI：
10.3390/cells9041020
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发表时间：
2020-04-01
期刊：
影响因子：
6
通讯作者：
Tsai, Jo-Ting
中科院分区：
文献类型：
--
作者：
Chang, Hang-Lung;Bamodu, Oluwaseun Adebayo;Tsai, Jo-Ting
背景资料：由于目前标准治疗策略的记录表现不佳，突出表现为治疗后（切除或局部消融）复发率高、化疗耐药、总生存率低以及全球发病率增加，肝细胞癌（HCC）构成了医学挑战。越来越多的证据表明，肝细胞癌干细胞（HCC-SC）在肝细胞癌的发生、耐药性、复发和进展中的存在。因此，靶向HCC-SC和非CSC的治疗策略至关重要。方法：最近，有越来越多的建议MALAT 1癌基因活性在肝癌，然而，它的作用在肝癌干性仍然是未知的。在此，我们研究了MALAT 1在HCC的SC样表型中的可能作用，并探索了MALAT 1调节HCC-SC样和转移表型的可能分子机制。结果如下：我们发现，相对于正常的，肝硬化的，或发育不良的肝脏条件，MALAT 1异常表达在HCC中，类似于其过度表达在Huh 7，Mahlavu，和SK-Hep 1 HCC细胞系，相比正常的肝细胞系THLE-2。我们还证明了MALAT 1表达与低分化状态之间的正相关性，在HCC中使用RNAscope。有趣的是，我们证明了shRNA介导的MALAT 1沉默同时下调了β-连环蛋白、Stat 3、c-Myc、CK 19、波形蛋白和Twist 1蛋白的表达水平，抑制了HCC致瘤性，并显著抑制了HCC细胞的HCC-SCs相关染料流出潜力，降低了它们的ALDH-1活性，部分原因是抑制了MALAT 1-β-连环蛋白相互作用。此外，使用TOP/FOP（TCL/LEF-Firefly luciferase）Flash、RT-PCR和western blot检测，我们发现沉默MALAT 1下调β-连环蛋白表达，失调经典Wnt信号通路，从而减弱HCC肿瘤球形成效率，同时减少CD 133+和CD 90 + HCC细胞群，并抑制SK-Hep 1荷瘤小鼠的肿瘤生长。结论：总而言之，我们的数据表明MALAT 1/Wnt是一种可靶向的候选分子，MALAT 1/Wnt的治疗靶向可能构成肝癌治疗的一种新的有前途的抗癌策略。
Background: With recorded under-performance of current standard therapeutic strategies as highlighted by high rates of post-treatment (resection or local ablation) recurrence, resistance to chemotherapy, poor overall survival, and an increasing global incidence, hepatocellular carcinoma (HCC) constitutes a medical challenge. Accumulating evidence implicates the presence of HCC stem cells (HCC-SCs) in HCC development, drug-resistance, recurrence, and progression. Therefore, treatment strategies targeting both HCC-SCs and non-CSCs are essential. Methods: Recently, there has been an increasing suggestion of MALAT1 oncogenic activity in HCC; however, its role in HCC stemness remains unexplored. Herein, we investigated the probable role of MALAT1 in the SCs-like phenotype of HCC and explored likely molecular mechanisms by which MALAT1 modulates HCC-SCs-like and metastatic phenotypes. Results: We showed that relative to normal, cirrhotic, or dysplastic liver conditions, MALAT1 was aberrantly expressed in HCC, similar to its overexpression in Huh7, Mahlavu, and SK-Hep1 HCC cells lines, compared to the normal liver cell line THLE-2. We also demonstrated a positive correlation between MALAT1 expression and poor cell differentiation status in HCC using RNAscope. Interestingly, we demonstrated that shRNA-mediated silencing of MALAT1 concomitantly downregulated the expression levels of beta-catenin, Stat3, c-Myc, CK19, vimentin, and Twist1 proteins, inhibited HCC oncogenicity, and significantly suppressed the HCC-SCs-related dye-effluxing potential of HCC cells and reduced their ALDH-1 activity, partially due to inhibited MALAT1-beta-catenin interaction. Additionally, using TOP/FOP (TCL/LEF-Firefly luciferase) Flash, RT-PCR, and western blot assays, we showed that silencing MALAT1 downregulates beta-catenin expression, dysregulates the canonical Wnt signaling pathway, and consequently attenuates HCC tumorsphere formation efficiency, with concurrent reduction in CD133+ and CD90+ HCC cell population, and inhibits tumor growth in SK-Hep1-bearing mice. Conclusions: Taken together, our data indicate that MALAT1/Wnt is a targetable molecular candidate, and the therapeutic targeting of MALAT1/Wnt may constitute a novel promising anticancer strategy for HCC treatment.