Role of Kupffer cells in arresting circulating tumor cells and controlling metastatic growth in the liver

Metastasis to the liver is a common event in clinical oncology. Blood-borne tumor cells (TCs) arriving to the liver sinusoids run into a special vascular bed. The lining of liver sinusoids is shared by Kupffer cells (KCs) and endothelial cells. KCs, liver-fixed macrophages, are responsible for detection and removal of "non-self" particles. To investigate their role in arresting blood-borne TCs and controlling tumor growth, we injected a syngeneic colon carcinoma cell line into a mesenteric vein of two groups of rats; one group was without Kupffer cells and the other normal controls. We removed the liver of these animals at different time intervals and performed immunohistochemical analysis with monoclonal antibodies (MoAbs) against our tumor cell line, three macrophage subpopulations, natural killer cells, and B and T lymphocytes. Additionally, we showed in vitro spontaneous cytotoxicity of KCs against our tumor cell line. Results suggest that KCs play a relevant role in arresting circulating TCs at the liver sinusoid, although it is limited to a small number of malignant cells. They also seem to play a major role in clearing neoplastic cells from the liver parenchyma, in controlling tumor growth in the very early stages of metastatic development, and in modulating the host immune response to cancer cells. (Hepatology 1996 May;23(5):1224-31)     

Clinicopathological analysis of colorectal cancer liver metastasis and intrahepatic cholangiocarcinoma: Are they just apples and oranges?

BACKGROUNDS/AIMS: Intrahepatic cholangiocarcinoma and colorectal cancer liver metastasis are the most primary and secondary adenocarcinoma of the liver, respectively. A large-scale long-term comparative study of these two cohort patient is lacking. METHODS: A total of 166 colorectal cancer liver metastasis patients and 206 intrahepatic cholangiocarcinoma patients who had undergone curative liver resection were retrospectively analysed. Among 206 intrahepatic cholangiocarcinoma, there were 47 intraductal growth type-intrahepatic cholangiocarcinoma and 159 non-intraductal growth type-intrahepatic cholangiocarcinoma. The demographics, clinicopathological data, immunohistochemical study and survival were analysed. RESULTS: The intrahepatic cholangiocarcinoma patients were more female-predominated, associated with hepatolithiasis, symptomatic, jaundiced, and with larger tumour size compared with those of colorectal cancer liver metastasis. Prognostic factors of intrahepatic cholangiocarcinoma were pathologic staging, histologic pattern and section margin; whereas prognostic factors of colorectal cancer liver metastasis were rectal origin, differentiation, section margin and bilobar distribution. CK7 and CK20 differentiated majority of intrahepatic cholangiocarcinoma from colorectal cancer liver metastasis, while CDX2 and MUC5AC helped to differentiate inconclusive cases. The 1-, 3-, 5- and 10-year survival rates of colorectal cancer liver metastasis were 77%, 31%, 20% and 14%, compared to 53%, 21%, 13% and 7% of intrahepatic cholangiocarcinoma (p=.0001). Furthermore, the survival of colorectal cancer liver metastasis was comparable to staged II intrahepatic cholangiocarcinoma (p=.8866) and intraductal growth type-intrahepatic cholangiocarcinoma (p=.1915). CONCLUSIONS: Demographics, precipitating factor, clinical manifestations, and prognostic factors of colorectal cancer liver metastasis and intrahepatic cholangiocarcinoma differed remarkably. High incidence of CDX2 and MUC2 expression in colorectal cancer liver metastasis and intraductal growth type-intrahepatic cholangiocarcinoma might explain their similar cytoarchitecture and survival.     

Contribution of matrilysin (MMP-7) to the metastatic pathway of human colorectal cancers

BACKGROUND/AIM: Matrilysin is one of the matrix metalloproteinases that has a critical role in tumour invasion, and is often expressed in gastrointestinal cancers. The aim of this study was to examine the role of matrilysin in metastasis of human colorectal cancers. PATIENTS (SUBJECTS)/METHODS: The relation between matrilysin expression and Dukes's type was investigated immunohistochemically in 83 surgically resected colorectal cancers, including five with liver metastasis. Moreover, the effects of matrilysin on the in vivo invasive and metastatic potential of colon cancer cells transfected with matrilysin cDNA were examined after subcutaneous injection into SCID mice. RESULTS: In 46% of primary and all of metastatic liver tumours, over 10% of cancer cells were stained positively for matrilysin. The expression of matrilysin correlated significantly with the presence of nodal or distant metastases (p<0.05). In addition, matrilysin transfectants formed invasive tumours and multiple liver metastases in SCID mice, without producing any significant difference in the subcutaneous tumour growth from mock transfectants. Casein zymography showed that the invading and metastasised tumours showed conspicuous matrilysin activity, which correlated with the number of metastatic lesions (p<0.001). CONCLUSIONS: Matrilysin showed a correlation with metastasis in a cohort of 83 colorectal cancer patients and marked metastatic potentiation in human colorectal cancer xenografts, indicating that it may play a critical role in the metastatic pathway of colorectal cancers.     

Influence of Kupffer cells and platelets on ischemia-reperfusion injury in mild steatotic liver

AIM: To investigate the effect of mild steatotic liver on ischemia-reperfusion injury by focusing on Kupffer cells (KCs) and platelets. METHODS: Wistar rats were divided into a normal liver group (N group) and a mild steatotic liver group (S group) induced by feeding a choline-deficient diet for 2 wk. Both groups were subjected to 20 min of warm ischemia followed by 120 min of reperfusion. The number of labeled KCs and platelets in sinusoids and the blood perfusion in sinusoids were observed by intravital microscopy (IVM), which was performed at 30, 60 and 120 min after reperfusion. To evaluate serum alanine aminotransferase as a marker of liver deterioration, blood samples were taken at the same time as IVM.RESULTS: In the S group, the number of platelets adhering to KCs decreased significantly compared with the N group (120 after reperfusion; 2.9±1.1 cells/acinus vs 4.8±1.2 cells/acinus, P<0.01). The number of KCs in sinusoids was significantly less in the S group than in the N group throughout the observation periods (before ischemia, 19.6±3.3 cells/acinus vs 28.2±4.1 cells/acinus, P<0.01 and 120 min after reperfusion, 29.0±4.3 cells/acinus vs 40.2±3.3 cells/acinus, P<0.01). The blood perfusion of sinusoids 120 min after reperfusion was maintained in the S group more than in the N group. Furthermore, elevation of serum alanine aminotransferase was lower in the S group than in the N group 120 min after reperfusion (99.7±19.8 IU/L vs 166.3±61.1 IU/L, P=0.041), and histological impairment of hepatocyte structure was prevented in the S group. CONCLUSION: Ischemia-reperfusion injury in mild steatotic liver was attenuated compared with normal liver due to the decreased number of KCs and the reduction of the KC-platelet interaction.     

Liver innate immune cells and insulin resistance: the multiple facets of Kupffer cells

Obesity, which affects 600 million adults worldwide, is a major risk factor for type 2 diabetes (T2D) and insulin resistance. Current therapies for these metabolic disorders include weight management by lifestyle intervention or bariatric surgery and pharmacological treatment with the aim of regulating blood glucose. Probably because of their short‐term effectiveness, these therapies have not been able to stop the rapidly rising prevalence of T2D over the past decades, highlighting an urgent need to develop new therapeutic strategies. The role of immune cells, such as macrophages, in insulin resistance has been extensively studied. Major advances have been made to elucidate the role of adipose tissue macrophages in these pathogeneses. Recently, anti‐inflammatory drugs have been suggested as an alternative treatment for T2D, and clinical trials of these agents are currently ongoing. In addition, results of previous clinical trials using antibodies against inflammatory cytokines, which showed modest effects, are now being rigorously re‐evaluated. However, it is still unclear how liver macrophages [termed Kupffer cells (KCs)], which constitute the major source of macrophages in the body, contribute to the development of insulin resistance. In this review, we will discuss the present understanding of the role of liver immune cells in the development of insulin resistance. We will particularly focus on KCs, which could represent an attractive target for the treatment of metabolic diseases.     

Floxuridine coupling with lactosaminated human albumin to increase drug efficacy on liver micrometastases

BACKGROUND: Conjugates of nucleoside analogues with galactosyl terminating peptides selectively enter hepatocytes through the asialoglycoprotein receptor. After intracellular release from the carrier, the drugs partly exit from hepatic cells into hepatic blood. AIMS: To establish whether administration of a conjugate of floxuridine with lactosaminated human albumin selectively enhances drug concentrations in hepatic blood. Floxuridine is a fluoropyrimidine active on human colorectal cancer, a tumour which metastasises first to the liver. METHODS: In rats injected with free or conjugated floxuridine, plasma levels of the drug were determined in hepatic veins and in inferior vena cava, in order to measure drug concentrations in hepatic blood and in the systemic circulation, respectively. RESULTS: Ratios between floxuridine levels in hepatic veins and those in systemic circulation were found to be seven times higher in rats injected with the conjugate (p=0.000). CONCLUSIONS: The present results suggest that coupling to lactosaminated albumin might improve the effect of floxuridine in adjuvant chemotherapy of colorectal cancer by exposing the cells of liver micrometastases (nourished by hepatic sinusoids) to enhanced drug concentrations.     

Viro-immune therapy:A new strategy for treatment of pancreatic cancer

Pancreatic ductal adenocarcinoma(PDAC) is an almost uniformly lethal disease with less than 5% survival at five years. This is largely due to metastatic disease, which is already present in the majority of patients when diagnosed. Even when the primary cancer can be removed by radical surgery, local recurrence occurs within one year in 50%-80% of cases. Therefore, it is imperative to develop new approaches for the treatment of advanced cancer and the prevention of recurrence after surgery. Tumour-targeted oncolytic viruses(TOVs) have become an attractive therapeutic agent as TOVs can kill cancer cells through multiple mechanisms of action, especially via virus-induced engagement of the immune response specifically against tumour cells. To attack tumour cells effectively, tumour-specific T cells need to overcome negative regulatory signals that suppress their activation or that induce tolerance programmes such as anergy or exhaustion in the tumour microenvironment. In this regard, the recent breakthrough in immunotherapy achieved with immune checkpoint blockade agents, such as anti-cytotoxic T-lymphocyte-associate protein 4, programmed death 1(PD-1) or PD-L1 antibodies, has demonstrated the possibility of relieving immune suppression in PDAC. Therefore, the combination of oncolytic virotherapy and immune checkpoint blockade agents may synergistically function to enhance the antitumour response, lending the opportunity to be the future for treatment of pancreatic cancer.     

Liver regeneration and tumour stimulation: implications of the renin–angiotensin system

Liver resection is the most effective treatment for primary liver tumours and metastasis to the liver, and remains the only potentially long‐term curative therapy for patients with colorectal cancer (CRC) liver metastases. Nevertheless, there is a significant incidence of tumour recurrence following liver resection. Cellular and molecular changes resulting from resection and the subsequent liver regeneration process may influence the kinetics of tumour growth, contributing to recurrence. Although commonly associated with the systemic homeostasis of blood pressure, fluid and electrolyte, the renin–angiotensin system (RAS) has recently been shown to play a role in regulating cell proliferation, apoptosis and angiogenesis in local organs as well as in malignancies. An electronic search of the English literature on the role of the RAS in liver regeneration and tumourigenesis was performed using PubMed, with additional relevant articles sourced from reference lists. Studies have shown that the blockade of the RAS pathway stimulates liver regeneration and inhibits tumour progression. An understanding of the role of RAS in liver regeneration and tumourigenesis may enable alternative strategies to improve patient outcome and survival after liver resection. This review will discuss the role of the RAS in liver regeneration and in tumour recurrence post‐liver resection. The potential of the RAS as a novel therapeutic target for CRC liver metastases patients undergoing liver resection will be outlined.     

关于肝癌治疗的策略

近年肝癌各种疗法的5年生存率已接近高限,瓶颈主要是转移复发。20世纪肝癌治疗均以消灭肿瘤为目标,近年已转变为消灭和改造并举。在消灭肿瘤的基础上,出现了多种调变残癌和调变机体的办法,如合并应用细胞因子、抗炎剂、分子靶向治疗剂、全身性干预以及中医中药等。还出现了一些潜在的治疗途径,如小RNA等,一些＂无关药物＂（如治疗结核病的利福平）也可望用于肝癌治疗。实验研究表明,常规疗法常通过上皮-间质转化而促进转移,研究其干预是提高现有疗法疗效的一条捷径,但同时需要提防＂过度治疗＂。总之,消灭肿瘤仍然是基本的,而调变肿瘤和机体则是重要的补充。     

基于权重基因共表达分析的结肠癌肝转移相关基因挖掘与验证

目的挖掘结肠癌肝转移过程中的核心基因模块和分子靶点,并验证其对临床预后及结肠癌转移能力的影响。 方法基于GEO数据库结肠癌肝转移测序样本,利用权重基因共表达网络分析（WGCNA）技术筛选转移相关基因模块。利用MCODE软件进一步挖掘结肠癌肝转移相关核心子模块并分析其功能。基于TCGA数据库,进行子模块基因对结肠癌预后影响的大临床样本验证。分子生物学方法验证子模块基因对结肠癌细胞系HCT116迁移和侵袭能力的影响。 结果WGCNA分析筛选出5个基因模块,其中模块1与结肠癌肝转移关系密切。模块1共包含4个核心子模块,主要参与G蛋白偶联受体信号调节、表观遗传学调控、mRNA的剪接调节等功能。大临床样本验证发现子模块4中的FOXC1基因与结肠癌患者生存率密切相关。敲减FOXC1在HCT116细胞中的表达后,HCT116的迁移能力（t=3.123,P=0.035）和侵袭能力（t=2.936,P=0.043）受到显著抑制。 结论本研究筛选出的结肠癌肝转移相关子模块可能具有重要的促转移作用,子模块基因FOXC1与结肠癌患者较差的生存率相关并具有促结肠癌转移能力。     

Selective or targeted gene/drug delivery for liver tumors: advantages and current status of local delivery

There are various disorders involving the liver. They include metabolic diseases, hepatitis, liver cirrhosis and cancer, the latter of which may be the most serious. Delivery of therapeutic genes or drugs should be targeted to either one of the following cells in the liver: hepatocytes, Kupffer cells and tumor endothelial cells, or to the tumor cells themselves. To maximize the therapeutic effect and minimize systemic toxicity or nontarget injuries, the sufficient amount or dose of genes or drugs should be specifically delivered to a target, with minimal exposure in their active forms to nontarget cells. There are diverse strategies to improve selective delivery or targeting efficiency. In this article, we present potential new therapeutic strategies and clinical developments for liver cancer, with a focus on the progress in the localized delivery of therapeutic agents using image-guided procedures.     

Local interaction of apoptotic hepatocytes and Kupffer cells in a rat model of systemic endotoxemia

Aim: There is strong evidence that hepatocellular apoptosis is not only initiated by circulating blood cells which become adherent within the endotoxemic liver, but also contributes to further sustain the inflammatory cell-cell response. Methods: Because previous studies assumed the importance of the role of cellular cross-talk in mediating inflammatory liver injury, we herein examined the activation of Kupffer cells (KCs) and their spatial coincidence with intrahepatic leukocyte adherence and hepatocellular apoptosis at 6 h after intraperitoneal exposure of rats with lipopolysaccharide (10 mg/kg). Results: In vivo multifluorescence microscopy revealed liver injury including nutritive perfusion failure, tissue hypoxia, leukocyte accumulation, as well as KC activation and parenchymal apoptotic cell death. Detailed spatial analysis revealed frequent colocalization of activated KCs with apoptotic hepatocytes. Colocalization was absent in saline-treated controls.Colocalization was confirmed by histochemistry, which showed ED1-positive KCs neighboring and engulfing TUNEL-positive hepatocytes. Colocalization of KCs with leukocytes ranged between 4% and 5% and did not increase in endotoxemic animals. Taken together, the present results indicate that apoptotic cell death of hepatocytes may stimulate phagocytosis by neighboring KCs. Direct KC-leukocyte contact seems not to be mandatory for cellular communication in the process of hepatocellular apoptosis. Conclusion: With respect to the fundamental importance of cell apoptosis, improved knowledge of these cell-cell interactions might allow the development of new therapeutic strategies through the regulation of apoptotic cell death.     

Natural history of hepatic metastases from colorectal cancer-pathobiological pathways with clinical significance

Colorectal cancer hepatic metastases represent the final stage of a multi-step biological process.This process starts with a series of mutations in colonic epithelial cells,continues with their detachment from the large intestine,dissemination through the blood and/or lymphatic circulation,attachment to the hepatic sinusoids and interactions with the sinusoidal cells,such as sinusoidal endothelial cells,Kupffer cells,stellate cells and pit cells.The metastatic sequence terminates with colorectal cancer cell invasion,adaptation and colonisation of the hepatic parenchyma.All these events,termed the colorectal cancer invasion-metastasis cascade,include multiple molecular pathways,intercellular interactions and expression of a plethora of chemokines and growth factors,and adhesion molecules,such as the selectins,the integrins or the cadherins,as well as enzymes including matrix metalloproteinases.This review aims to present recent advances that provide insights into these cell-biological events and emphasizes those that may be amenable to therapeutic targeting.     

Benefit of FOLFOX to unresectable liver metastases secondary from colorectal carcinoma in an oncologic emergency

Liver metastasis is an important prognostic factor in colorectal cancer. The efficacy of resection of metastatic lesions in liver metastasis of colorectal cancer is also widely recognized. However, studies on treatment methods of unresectable cases have not been sufficient and obtaining complete remission (CR) for liver metastasis is rare with chemotherapy. Selection of reliable chemotherapy for unresectable liver metastasis is an urgent necessity. The usefulness of oxaliplatin, 5-flurouracil and leucovorin combination therapy (FOLFOX) has recently been reported, but CR of liver metastasis is rare. The current status and new therapeutic significance of FOLFOX therapy are discussed based on the literature of colorectal cancer chemotherapy to date, and the clinical experience in which we obtained CR for liver metastasis is reported. The patient had stage IV rectal cancer, perforative peritonitis, pelvic abscess and simultaneous multiple liver metastasis. The patient underwent an emergency operation using the Hartmann's procedure. Liver metastasis is considered to be a prognostic factor and FOLFOX was selected as the postoperative chemotherapy, CR of the liver metastasis was obtained. FOLFOX was suggested to have new clinical significance in oncologic emergencies against unresectable liver metastasis in colorectal cancer and should serve as adjuvant chemotherapy that will contribute to improvement of treatment results.     

Lipopolysaccharide is a cofactor for malondialdehyde-acetaldehyde adduct-mediated cytokine/chemokine release by rat sinusoidal liver endothelial and Kupffer cells

BACKGROUND: The nonparenchymal cells of the liver have been suggested to play a significant role in the inflammatory processes observed in the development and/or progression of alcoholic liver disease. Our laboratories have shown that malondialdehyde-acetaldehyde (MAA)-modified proteins can induce immune responses, cytokine/chemokine secretion, and antigen processing and presentation by liver sinusoidal endothelial cells (SECs). Another molecule that has been shown to induce similar types of responses in Kupffer cells (KCs) is lipopolysaccharide (LPS). Because these materials induce similar responses, it was the purpose of this study to investigate the relationship between LPS and MAA-modified proteins in the development of proinflammatory responses by SECs and KCs. METHODS: For these studies, SECs and KCs were isolated from chow-fed, pair-fed, and ethanol-fed rats. Cells were stimulated with media alone, bovine serum albumin (Alb), or MAA-modified Alb (MAA-Alb) in the presence or absence of LPS 1 ng/ml, and the supernatants were assayed by enzyme-linked immunosorbent assay for tumor necrosis factor alpha, macrophage chemotactic protein 1, and macrophage inhibitory protein. RESULTS: All three cytokines/chemokines were 3 to 5 times higher when SECs or KCs were stimulated by MAA-Alb in the presence of LPS, in contrast to cells stimulated with Alb or media in the presence of LPS. Chronic ethanol consumption (6 weeks) had variable effects on the secretion of these cytokines/chemokines but in general did not alter the increased secretion in response to MAA-Alb in the presence of LPS. CONCLUSIONS: These studies strongly suggest that the sensitization of SECs and KCs by LPS plays a significant role in the development and/or progression of alcoholic liver disease, and the subsequent activation by MAA-modified proteins may be a mechanism by which proinflammatory processes are initiated.     

Searching for the link; mechanisms underlying liver regeneration and recurrence of colorectal liver metastasis post partial hepatectomy

Despite excellent treatment of primary colorectal cancer, the majority of deaths occur as a result of metastasis to the liver. Recent population studies have estimated that one quarter of patients with colorectal cancer will incur synchronous or metachronous colorectal liver metastasis. However, only one quarter of these patients will be eligible for potentially curative resection. Tumor recurrence occurs in reportedly 60% of patients undergoing hepatic resection, and the majority of intrahepatic recurrence occurs within the first 6 months of surgery. The livers innate ability to restore its homeostatic size, and volume facilitates major hepatic resection that currently offers the only chance of cure to patients with extensive hepatic metastases. Experimental and clinical evidence supports the notion that following partial hepatectomy, liver regeneration (LR) paradoxically drives tumor progression and increases the risk of recurrence. It is becoming increasingly clear that the processes that drive liver organogenesis, regeneration, and tumor progression are inextricably linked. This presents a major hurdle in the management of colorectal liver metastasis and other hepatic malignancies because therapies that reduce the risk of recurrence without hampering LR are sought. The processes and pathways underlying these phenomena are multiple, complex, and cross‐communicate. In this review, we will summarize the common mechanisms contributing to both LR and tumor recurrence.     

Roles of hepatic stellate cells in acute liver failure: From the perspective of inflammation and fibrosis

Acute liver failure(ALF) usually results in hepatocellular dysfunction and coagulopathy and carries a high mortality rate. Hepatic stellate cells(HSCs) are famous for their role in liver fibrosis. Although some recent studies revealed that HSCs might participate in the pathogenesis of ALF, the accurate mechanism is still not fully understood. This review focuses on the recent advances in understanding the functions of HSCs in ALF and revealed both protective and promotive roles during the pathogenesis of ALF: HSC activation participates in the maintenance of cell attachment and the architecture of liver tissue via extracellular matrix production and assists liver regeneration by producing growth factors; and HSC inflammation plays a role in relaying inflammation signaling from sinusoids to parenchyma via secretion of inflammatory cytokines.A better understanding of roles of HSCs in the pathogenesis of ALF may lead to improvements and novel strategies for treating ALF patients.     

Asymptomatic isolated coccygeal metastasis in low rectal carcinoma

As well as being relatively rare, osseous metastases from colorectal cancer are frequently asymptomatic and represent a late manifestation of disease. We report a case of an unidentified, asymptomatic coccygeal metastasis discovered on histological processing of the resection specimen from a patient with locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy followed by radical abdomino-perineal resection with coccygectomy. The anatomical explanation for this finding may involve passage of tumour cells via the vertebral venous plexus.     

Advances in understanding of colorectal liver metastasis and implications for the clinic

Colorectal cancer is one of the most common cancers in both the USA and Europe. Over the course of diagnosis, treatment and surveillance, up to 50% of these patients will develop metastases to their liver. In the past 20 years alone, there have been multiple advances in the management of these colorectal metastases to the liver. These advances have been made in characterization of these tumors, diagnosis and in treatment, both locally and systemically. Because of this progress, there are subsets of patients with this stage IV disease who are cured of their disease. While significant progress has been made, there still exist limitations in the management of metastatic colorectal cancer to the liver. This review outlines current strategies and highlights recent advances in the management of colorectal liver metastases.