Over several decades, a hierarchical cancer stem cell (CSC) model has been established in development of solid cancers, including hepatocellular carcinoma(HCC). In terms of this concept, HCCs originate from liver CSCs. Clinically HCCs show a wide range of manifestations from slow growth to very aggressive metastasis. One of the reasons may be that liver CSCs originate from different cells. This review describes the basic concept of CSCs and the cellular origin of liver CSCs.
Carcinoma, Hepatocellular ; Liver ; Liver Neoplasms* ; Neoplasm Metastasis ; Neoplastic Stem Cells ; Stem Cells*

Hepatocellular carcinoma (HCC) accounts for 85% to 90% of primary liver cancers and generally has a poor prognosis. The hierarchical model, which posits that HCC originates from liver cancer stem cells (CSCs), is now widely accepted, as it is for other cancer types. As CSCs typically reside in the G0 phase of the cell cycle, they are resistant to conventional chemotherapy. Therefore, to effectively treat HCC, developing therapeutic strategies that target liver CSCs is essential. Clinically, HCCs exhibit a broad spectrum of pathological and clinical characteristics, ranging from well-differentiated to poorly differentiated forms, and from slow-growing tumors to aggressive ones with significant metastatic potential. Some patients with HCC also show features of cholangiocarcinoma. This HCC heterogeneity may arise from the diverse cellular origins of liver CSCs. This review explores the normal physiology of liver regeneration and provides a comprehensive overview of hepatocarcinogenesis, including cancer initiation, isolation of liver CSCs, molecular signaling pathways, and microRNAs. Additionally, the cellular origins of liver CSCs are reviewed, emphasizing hematopoietic and mesenchymal stem cells, along with the well-known hepatocytes and hepatic progenitor cells.

Hepatocellular carcinoma (HCC) accounts for 85% to 90% of primary liver cancers and generally has a poor prognosis. The hierarchical model, which posits that HCC originates from liver cancer stem cells (CSCs), is now widely accepted, as it is for other cancer types. As CSCs typically reside in the G0 phase of the cell cycle, they are resistant to conventional chemotherapy. Therefore, to effectively treat HCC, developing therapeutic strategies that target liver CSCs is essential. Clinically, HCCs exhibit a broad spectrum of pathological and clinical characteristics, ranging from well-differentiated to poorly differentiated forms, and from slow-growing tumors to aggressive ones with significant metastatic potential. Some patients with HCC also show features of cholangiocarcinoma. This HCC heterogeneity may arise from the diverse cellular origins of liver CSCs. This review explores the normal physiology of liver regeneration and provides a comprehensive overview of hepatocarcinogenesis, including cancer initiation, isolation of liver CSCs, molecular signaling pathways, and microRNAs. Additionally, the cellular origins of liver CSCs are reviewed, emphasizing hematopoietic and mesenchymal stem cells, along with the well-known hepatocytes and hepatic progenitor cells.

Hepatocellular carcinoma (HCC) accounts for 85% to 90% of primary liver cancers and generally has a poor prognosis. The hierarchical model, which posits that HCC originates from liver cancer stem cells (CSCs), is now widely accepted, as it is for other cancer types. As CSCs typically reside in the G0 phase of the cell cycle, they are resistant to conventional chemotherapy. Therefore, to effectively treat HCC, developing therapeutic strategies that target liver CSCs is essential. Clinically, HCCs exhibit a broad spectrum of pathological and clinical characteristics, ranging from well-differentiated to poorly differentiated forms, and from slow-growing tumors to aggressive ones with significant metastatic potential. Some patients with HCC also show features of cholangiocarcinoma. This HCC heterogeneity may arise from the diverse cellular origins of liver CSCs. This review explores the normal physiology of liver regeneration and provides a comprehensive overview of hepatocarcinogenesis, including cancer initiation, isolation of liver CSCs, molecular signaling pathways, and microRNAs. Additionally, the cellular origins of liver CSCs are reviewed, emphasizing hematopoietic and mesenchymal stem cells, along with the well-known hepatocytes and hepatic progenitor cells.

Hepatocellular carcinoma (HCC) accounts for 85% to 90% of primary liver cancers and generally has a poor prognosis. The hierarchical model, which posits that HCC originates from liver cancer stem cells (CSCs), is now widely accepted, as it is for other cancer types. As CSCs typically reside in the G0 phase of the cell cycle, they are resistant to conventional chemotherapy. Therefore, to effectively treat HCC, developing therapeutic strategies that target liver CSCs is essential. Clinically, HCCs exhibit a broad spectrum of pathological and clinical characteristics, ranging from well-differentiated to poorly differentiated forms, and from slow-growing tumors to aggressive ones with significant metastatic potential. Some patients with HCC also show features of cholangiocarcinoma. This HCC heterogeneity may arise from the diverse cellular origins of liver CSCs. This review explores the normal physiology of liver regeneration and provides a comprehensive overview of hepatocarcinogenesis, including cancer initiation, isolation of liver CSCs, molecular signaling pathways, and microRNAs. Additionally, the cellular origins of liver CSCs are reviewed, emphasizing hematopoietic and mesenchymal stem cells, along with the well-known hepatocytes and hepatic progenitor cells.

Alcoholic hepatitis is a leading cause of liver failure in which the increased production of tumor necrosis factor alpha (TNFalpha) plays a critical role in progression of alcoholic liver disease. In the present study, we investigated the effects of cilostazol, a selective inhibitor of type III phosphodiesterase on ethanol-mediated TNFalpha production in vitro and in vivo, and the effect of cilostazol was compared with that of pentoxifylline, which is currently used in clinical trial. RAW264.7 murine macrophages were pretreated with ethanol in the presence or absence of cilostazol then, stimulated with lipopolysacchride (LPS). Cilostazol significantly suppressed the level of LPS-stimulated TNFalpha mRNA and protein with a similar degree to that by pentoxifylline. Cilostazol increased the basal AMP-activated protein kinase (AMPK) activity as well as normalized the decreased AMPK by LPS. AICAR, an AMPK activator and db-cAMP also significantly decreased TNFalpha production in RAW264.7 cells, but cilostazol did not affect the levels of intracellular cAMP and reactive oxygen species (ROS) production. The in vivo effect of cilostazol was examined using ethanol binge drinking (6 g/kg) mice model. TNFalpha mRNA and protein decreased in liver from ethanol gavaged mice compared to that from control mice. Pretreatment of mice with cilostazol or pentoxifylline further reduced the TNFalpha production in liver. These results demonstrated that cilostazol effectively decrease the ethanol-mediated TNFalpha production both in murine macrophage and in liver from binge drinking mice and AMPK may be responsible for the inhibition of TNFalpha production by cilostazol.
Aminoimidazole Carboxamide ; AMP-Activated Protein Kinases ; Animals ; Binge Drinking ; Ethanol ; Hepatitis, Alcoholic ; Liver ; Liver Diseases, Alcoholic ; Liver Failure ; Macrophages ; Mice ; Pentoxifylline ; Reactive Oxygen Species ; Ribonucleotides ; RNA, Messenger ; Tetrazoles ; Tumor Necrosis Factor-alpha

The paradigm of chronic liver diseases has been shifting. Although hepatitis B and C viral infections are still the main causes of liver cirrhosis and hepatocellular carcinoma (HCC), the introduction of effective antiviral drugs may control or cure them in the near future. In contrast, the burden of nonalcoholic fatty liver disease (NAFLD) has been increasing for decades, and 25 to 30% of the general population in Korea is estimated to have NAFLD. Over 10% of NAFLD patients may have nonalcoholic steatohepatitis (NASH), a severe form of NAFLD. NASH can progress to cirrhosis and HCC. NASH is currently the second leading cause to be placed on the liver transplantation list in the United States. NAFLD is associated with obesity, type 2 diabetes, dyslipidemia, and metabolic syndrome. The pathophysiology is complex and associated with lipotoxicity, inflammatory cytokines, apoptosis, and insulin resistance. The only proven effective treatment is weight reduction by diet and exercise. However, this may not be effective for advanced fibrosis or cirrhosis. Therefore, effective drugs are urgently needed for treating these conditions. Unfortunately, no drugs have been approved for the treatment of NASH. Many pharmaceutical companies are trying to develop new drugs for the treatment of NASH. Some of them are in phase 2 or 3 clinical trials. Here, pharmacologic therapies in clinical trials, as well as the basic principles of drug therapy, will be reviewed, focusing on pathophysiology.
Antiviral Agents ; Apoptosis ; Carcinoma, Hepatocellular ; Cytokines ; Diet ; Drug Therapy ; Dyslipidemias ; Fibrosis ; Hepatitis B ; Humans ; Insulin Resistance ; Korea ; Liver Cirrhosis ; Liver Diseases ; Liver Transplantation ; Non-alcoholic Fatty Liver Disease ; Obesity ; United States ; Weight Loss

The paradigm of chronic liver diseases has been shifting. Although hepatitis B and C viral infections are still the main causes of liver cirrhosis and hepatocellular carcinoma (HCC), the introduction of effective antiviral drugs may control or cure them in the near future. In contrast, the burden of nonalcoholic fatty liver disease (NAFLD) has been increasing for decades, and 25 to 30% of the general population in Korea is estimated to have NAFLD. Over 10% of NAFLD patients may have nonalcoholic steatohepatitis (NASH), a severe form of NAFLD. NASH can progress to cirrhosis and HCC. NASH is currently the second leading cause to be placed on the liver transplantation list in the United States. NAFLD is associated with obesity, type 2 diabetes, dyslipidemia, and metabolic syndrome. The pathophysiology is complex and associated with lipotoxicity, inflammatory cytokines, apoptosis, and insulin resistance. The only proven effective treatment is weight reduction by diet and exercise. However, this may not be effective for advanced fibrosis or cirrhosis. Therefore, effective drugs are urgently needed for treating these conditions. Unfortunately, no drugs have been approved for the treatment of NASH. Many pharmaceutical companies are trying to develop new drugs for the treatment of NASH. Some of them are in phase 2 or 3 clinical trials. Here, pharmacologic therapies in clinical trials, as well as the basic principles of drug therapy, will be reviewed, focusing on pathophysiology.

Alcohol-related liver disease (ALD) is a serious global health concern, characterized by liver inflammation and progressive fibrosis. There are no Food and Drug Administration-approved drugs, thus effective treatments are needed. Severe alcoholic hepatitis (AH) is the most severe manifestation of ALD, with a 28-day mortality rate ranging from 20% to 50%. For decades, pentoxifylline, an antiplatelet agent, has been used off-label for the treatment of severe AH owingto its tumor necrosis factor-α inhibition properties. However, the STOPAH trial did not revealthe survival benefit of pentoxifylline. Consequently, pentoxifylline is no longer recommended as the first-line therapy for severe AH. In contrast, cilostazol is widely used as an antiplatelet agent in cardiovascular medicine and demonstrates promising results. Cilostazol is a selective phosphodiesterase type 3 inhibitor, whereas pentoxifylline is non-selective. Recent studies using experimental models of alcohol-induced liver injury and other liver diseases have yielded promising results. Although cilostazol shows promise for hepatoprotective effects, it has not yet been evaluated in human clinical trials. In this review, we will explore the mechanism underlying the hepatoprotective effects of cilostazol, along with the pathophysiology of alcohol-induced liver injury, addressing the pressing need for effective therapeutic options for patients with ALD.

Alcohol-related liver disease (ALD) is a serious global health concern, characterized by liver inflammation and progressive fibrosis. There are no Food and Drug Administration-approved drugs, thus effective treatments are needed. Severe alcoholic hepatitis (AH) is the most severe manifestation of ALD, with a 28-day mortality rate ranging from 20% to 50%. For decades, pentoxifylline, an antiplatelet agent, has been used off-label for the treatment of severe AH owingto its tumor necrosis factor-α inhibition properties. However, the STOPAH trial did not revealthe survival benefit of pentoxifylline. Consequently, pentoxifylline is no longer recommended as the first-line therapy for severe AH. In contrast, cilostazol is widely used as an antiplatelet agent in cardiovascular medicine and demonstrates promising results. Cilostazol is a selective phosphodiesterase type 3 inhibitor, whereas pentoxifylline is non-selective. Recent studies using experimental models of alcohol-induced liver injury and other liver diseases have yielded promising results. Although cilostazol shows promise for hepatoprotective effects, it has not yet been evaluated in human clinical trials. In this review, we will explore the mechanism underlying the hepatoprotective effects of cilostazol, along with the pathophysiology of alcohol-induced liver injury, addressing the pressing need for effective therapeutic options for patients with ALD.