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Tumor metastasis is a complex process. A better understanding of the mechanistic underpinnings of the metastatic cascade could uncover approaches to better prevent and target metastases. Here, we integrated transcriptomic profiling in primary esophageal squamous cell carcinoma (ESCC) and matched lymph node metastatic tissues and genome-wide CRISPR/Cas9 functional screening to identify the key drivers of cancer metastasis. Anoctamin 1 (ANO1) expression was found to be elevated in primary tumors and further increased in metastatic tissues. High expression of ANO1 was associated with poor patient survival, and ANO1 overexpression promoted cancer invasion and metastasis. Mechanistically, ANO1 inactivated the LXR pathway and increased intracellular cholesterol accumulation by interacting with JUN to repress the transcription of cholesterol hydroxylase, CYP27A1. In a paracrine manner, IL1β secreted from ANO1-expressing ESCC cancer cells activated NF-κB signaling in fibroblasts to stimulate production of the chemokine CCL1, which in turn enhanced invasion of ESCC cancer cells. Furthermore, molecular docking and in silico screening of 1,500,000 small molecules identified K786–4469 as a lead compound that targeted ANO1 and suppressed cancer metastasis in vitro and in vivo. Overall, these findings uncover a noncanonical function of ANO1 in regulating cholesterol metabolism and fibroblast function, revealing ANO1 as a potential prognostic biomarker and therapeutic target for metastatic ESCC. Significance: Metastatic cancer cells upregulate ANO1 to activate cell-intrinsic and -extrinsic mechanisms that alter cholesterol metabolism and stimulate fibroblasts, which can be targeted with ANO1 inhibitors to inhibit metastatic growth. See related commentary by Singh and Mehla, p. 1759

Hepatocellular carcinoma (HCC) remains one of the leading causes of cancer-related death and has a poor prognosis worldwide, thus, more effective drugs are urgently needed. In this article, a small molecule drug library composed of 1,056 approved medicines from the FDA was used to screen for anticancer drugs. The tetracyclic compound maprotiline, a highly selective noradrenergic reuptake blocker, has strong antidepressant efficacy. However, the anticancer effect of maprotiline remains unclear. Here, we investigated the anticancer potential of maprotiline in the HCC cell lines Huh7 and HepG2. We found that maprotiline not only significantly restrained cell proliferation, colony formation and metastasis in vitro but also exerted antitumor effects in vivo. In addition to the antitumor effect alone, maprotiline could also enhance the sensitivity of HCC cells to sorafenib. The depth studies revealed that maprotiline substantially decreased the phosphorylation of sterol regulatory element-binding protein 2 (SREBP2) through the ERK signaling pathway, which resulted in decreased cholesterol biosynthesis and eventually impeded HCC cell growth. Furthermore, we identified cellular retinoic acid binding protein 1 (CRABP1) as a direct target of maprotiline. In conclusion, our study provided the first evidence showing that maprotiline could attenuate cholesterol biosynthesis to inhibit the proliferation and metastasis of HCC cells through the ERK-SREBP2 signaling pathway by directly binding to CRABP1, which supports the strategy of repurposing maprotiline in the treatment of HCC.

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignant tumors with poor survival. It is urgent to search for new efficient drugs with good stability and safety for clinical therapy. This study aims to identify potential anticancer drugs from a compound library consisting of 429 natural products. Echinatin, a compound isolated from the Chinese herb Glycyrrhiza uralensis Fisch, was found to markedly induce apoptosis and inhibit proliferation and colony-formation ability in ESCC. Confocal fluorescence microscopy data showed that echinatin significantly induced autophagy in ESCC cells, and autophagy inhibitor bafilomycinA1 attenuated the suppressive effects of echinatin on cell viability and apoptosis. Mechanistically, RNA sequencing coupled with bioinformatics analysis and a series of functional assays revealed that echinatin induced apoptosis and autophagy through inactivation of AKT/mTOR signaling pathway, whereas constitutive activation of AKT significantly abrogated these effects. Furthermore, we demonstrated that echinatin had a significant antitumor effect in the tumor xenograft model and markedly suppressed cell migration and invasion abilities of ESCC cells in a dose-dependent manner. Our findings provide the first evidence that echinatin could be a novel therapeutic strategy for treating ESCC.