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Hepatocellular carcinoma (HCC), one of the most common malignant cancers worldwide, is associated with substantial mortality. Because HCCs have strong resistance to conventional chemotherapeutic agents, novel therapeutic strategies are needed to improve survival in patients with HCC. The multicellular tumor spheroid (MCTS) model is a powerful method for anticancer research because of its ability to mimic the complexity and heterogeneity of tumor tissue, the three-dimensional cellular context of tumor tissue, and the pathophysiological gradients of in vivo tumors. However, it is difficult to obtain meaningful results from the MCTS model without considering the conditions of clinical tumors. We, therefore, provided a proof of concept to determine whether spheroid models simulate in vivo tumor microenvironments. Through a high-throughput screening for HCC therapy using the MCTS model, we selected inhibitors of Na+/K+-ATPase (ouabain and digoxin) that could suppress cell growth and migration via inhibition of the epithelial-mesenchymal transition of HCC in vivo and in vitro. The results showed that this model provides a new paradigm for high-throughput drug screening and will significantly improve the efficiency of identifying new drugs for HCC treatment. Through utilization of MCTS models, here we found that inhibitors of Na+/K+-ATPase may be feasible as a novel target to sensitize HCC cells. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is among the most common malignant cancers worldwide, with an increasing incidence associated with an increase in deaths due to liver cancer. HCC is typically detected at an advanced stage in patients with underlying liver dysfunction, resulting in high mortality. The identification of HCC-specific targets represents a desired but unmet need for liver cancer treatment. To identify potentially novel HCC therapeutic targets, we performed a secretome analysis using HCC spheroids. Sorbitol dehydrogenase (SORD) was identified as uniquely enriched in the secretomes and lysates derived from HCC spheroids, and high SORD expression in HCC tissues was associated with favorable effects on overall survival among patients with liver cancer. We found that the introduction of excess SORD in HCC cells inhibited tumor growth and stemness by enhancing necroptosis signal and bypassing energy-yielding pathways through regulation of lactate dehydrogenase A (LDHA) expression and mitochondrial dynamics. Treatment with human recombinant SORD (hrSORD) controlled HCC cell growth and regulated macrophage polarization in the tumor microenvironment. These results demonstrate that SORD plays critical functional roles in HCC suppression through polyol pathway-independent mechanisms, suggesting that targeting SORD expression might represent a promising therapeutic strategy for liver cancer therapy. [ABSTRACT FROM AUTHOR]

Background: Hepatocellular carcinoma (HCC) is one of the most common malignant cancers worldwide, and liver cancer has increased in mortality due to liver cancer because it was detected at an advanced stages in patients with liver dysfunction, making HCC a lethal cancer. Accordingly, we aim to new targets for HCC drug discovery using HCC tumor spheroids. Methods: Our comparative proteomic analysis of HCC cells grown in culture as monolayers (2D) and spheroids (3D) revealed that argininosuccinate synthase 1 (ASS1) expression was higher in 3D cells than in 2D cells due to upregulated endoplasmic reticulum (ER) stress responses. We investigated the clinical value of ASS1 in Korean patients with HCC. The mechanism underlying ASS1-mediated tumor suppression was investigated in HCC spheroids. ASS1-mediated improvement of chemotherapy efficiency was observed using high content screening in an HCC xenograft mouse model. Results: Studies of tumor tissue from Korean HCC patients showed that, although ASS1 expression was low in most samples, high levels of ASS1 were associated with favorable overall survival of patients. Here, we found that bidirectional interactions between ASS1 ER stress responses in HCC-derived multicellular tumor spheroids can limit HCC progression. ASS1 overexpression effectively inhibited tumor growth and enhanced the efficacy of in vitro and in vivo anti-HCC combination chemotherapy via activation of the PERK/eIF2α/ATF4/CHOP axis, but was not dependent on the status of p53 and arginine metabolism. Conclusions: These results demonstrate the critical functional roles for the arginine metabolism–independent tumor suppressor activity of ASS1 in HCC and suggest that upregulating ASS1 in these tumors is a potential strategy in HCC cells with low ASS1 expression. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is one of the most malignant human cancers, with a high mortality rate worldwide. Within an HCC tumor, cancer stem cells (CSCs) are responsible for tumor maintenance and progression and may contribute to resistance to standard HCC treatments. Previously, we characterized CD133+ cells as CSCs in primary HCC and identified chromenopyrimidinone (CPO) as a novel therapeutic for the effective treatment of CD133+ HCC. However, the biological function and molecular mechanism of CD133 remain unclear. Epigenetic alterations of CSCs have impacts on tumor initiation, progression, and therapeutic response. Here, we found that pharmacological and genetic depletion of CD133 in HCC attenuated the activity of DNA methyltransferases via control of DNMT3B stabilization. Genes were ranked by degree of promoter hypo/hyper methylation and significantly differential expression to create an "epigenetically activated by CPO" ranked genes list. Through this epigenetic analysis, we found that CPO treatment altered DNA methylation-mediated oncogenic signaling in HCCs. Specifically, CPO treatment inhibited Adenylyl cyclase-associated protein 1 (CAP1) expression, thereby reducing FAK/ERK activity and EMT-related proteins in HCC. Moreover, CPO improved the efficacy of sorafenib by inhibiting CAP1 expression and FAK/ERK activation in sorafenib-resistant HCC. These novel mechanistic insights may ultimately open up avenues for strategies targeting DNA methylation in liver cancer stem cells and provides novel therapeutic function of CPO for the effective treatment of sorafenib-resistant HCC. • CD133 controlled the activity of DNMTs in HCC. • Chromenopyrimidinone(CPO) attenuated DNMT activity via inhibition of DNMT3B in HCC. • CPO induced inhibition CAP1 expression and FAK/ERK activity in HCC. • CPO improved the efficacy of sorafenib in sorafenib-resistant HCC. [ABSTRACT FROM AUTHOR]