Induction of E-selectin after partial hepatectomy promotes metastases to liver in mice

One Shoot, Two Birds: Alleviating Inflammation Caused by Ischemia/Reperfusion Injury to Reduce the Recurrence of Hepatocellular Carcinoma

Inflammation is crucial to tumorigenesis and the development of metastasis. Hepatic ischemia/reperfusion injury (IRI) is an unresolved problem in liver resection and transplantation which often establishes and remodels the inflammatory microenvironment in liver. More and more experimental and clinical evidence unmasks the role of hepatic IRI and associated inflammation in promoting the recurrence of hepatocellular carcinoma (HCC). Meanwhile, approaches aimed at alleviating hepatic IRI, such as machine perfusion, regulating the gut-liver axis, and targeting key inflammatory components, have been proved to prevent HCC recurrence. This review article highlights the underlying mechanisms and promising therapeutic strategies to reduce tumor recurrence through alleviating inflammation induced by hepatic IRI.

Meta-analysis of the effect of the pringle maneuver on long-term oncological outcomes following liver resection

Hepatic pedicle clamping reduces intraoperative blood loss and the need for transfusion, but its long-term effect on survival and recurrence remains controversial. The aim of this meta-analysis was to evaluate the effect of the Pringle maneuver (PM) on long-term oncological outcomes in patients with primary or metastatic liver malignancies who underwent liver resection. Literature was searched in the Cochrane Central Register of Controlled Trials (CENTRAL), Medline (via PubMed), and Web of Science databases. Survival was measured as the survival rate or as a continuous endpoint. Pooled estimates were represented as odds ratios (ORs) using the Mantel–Haenszel test with a random-effects model. The literature search retrieved 435 studies. One RCT and 18 NRS, including 7480 patients who underwent liver resection with the PM (4309 cases) or without the PM (3171 cases) were included. The PM did not decrease the 1-year overall survival rate (OR 0.86; 95% CI 0.67–1.09; P = 0.22) or the 3- and 5-year overall survival rates. The PM did not decrease the 1-year recurrence-free survival rate (OR 1.06; 95% CI 0.75–1.50; P = 0.75) or the 3- and 5-year recurrence-free survival rates. There is no evidence that the Pringle maneuver has a negative effect on recurrence-free or overall survival rates.

Shorter Survival after Liver Pedicle Clamping in Patients Undergoing Liver Resection for Hepatocellular Carcinoma Revealed by a Systematic Review and Meta-Analysis

Simple Summary

Hepatocellular carcinoma (HCC) is the most prevalent tumor of the liver and represents the second most common cause of oncological-related deaths worldwide. Despite all progress made in the field, surgical resection or liver transplantation are, at the moment, the only curative therapies available. Liver resection, especially for large, central tumors, are at risk of important bleeding. Significative hemorrhage during HCC resections have been linked to an increased rate of post-operative complications and tumor recurrence. Therefore, hepatic pedicle clamping during surgery has been used in order to reduce the bleeding risks. However, this method induces ischemia/reperfusion injuries, which has also been associated with tumor recurrence. For this reason, we aimed to evaluate if pedicle clamping is indeed associated with tumor recurrence and shorter survival, by performing a systematic review of the literature and meta-analysis.

Abstract

Liver pedicle clamping minimizes surgical bleeding during hepatectomy. However, by inducing ischemia-reperfusion injury to the remnant liver, pedicle clamping may be associated with tumor recurrence in the regenerating liver. Hepatocellular carcinoma (HCC) having a high rate of recurrence, evidences demonstrating an eventual association with pedicle clamping is strongly needed. We did a systematic review of the literature until April 2020, looking at studies reporting the impact of liver pedicle clamping on long-term outcomes in patients undergoing liver resection for HCC. Primary and secondary outcomes were overall survival (OS) and disease-free survival, respectively. Results were obtained by random-effect meta-analysis and expressed as standardized mean difference (SMD). Eleven studies were included, accounting for 8087 patients. Results of seven studies were pooled in a meta-analysis. Findings indicated that, as compared to control patients who did not receive liver pedicle clamping, those who did had a significantly shorter OS (SMD = −0.172, 95%CI: −0.298 to −0.047, p = 0.007, I² = 76.8%) and higher tumor recurrence rates (odds ratio 1.36 1.01 to 1.83. p = 0.044, I² = 50.7%). This meta-analysis suggests that liver pedicle clamping may have a deleterious impact on long-term outcomes. An individual patient-data meta-analysis of randomized trials evaluating liver pedicle clamping is urgently needed.

The Impact of Liver Graft Injury on Cancer Recurrence Posttransplantation

Liver transplantation is the most effective treatment for selected patients with hepatocellular carcinoma. However, cancer recurrence, posttransplantation, remains to be the critical issue that affects the long-term outcome of hepatocellular carcinoma recipients. In addition to tumor biology itself, increasing evidence demonstrates that acute-phase liver graft injury is a result of hepatic ischemia reperfusion injury (which is an inevitable consequence during liver transplantation) and may promote cancer recurrence at late phase posttransplantation. The liver grafts from living donors, donors after cardiac death, and steatotic donors have been considered as promising sources of organs for liver transplantation and are associated with high incidence of liver graft injury. The acute-phase liver graft injury will trigger a series of inflammatory cascades, which may not only activate the cell signaling pathways regulating the tumor cell invasion and migration but also mobilize the circulating progenitor and immune cells to facilitate tumor recurrence and metastasis. The injured liver graft may also provide the favorable microenvironment for tumor cell growth, migration, and invasion through the disturbance of microcirculatory barrier function, induction of hypoxia and angiogenesis. This review aims to summarize the latest findings about the role and mechanisms of liver graft injury resulted from hepatic ischemia reperfusion injury on tumor recurrence posttransplantation, both in clinical and animal cohorts.

PPARγ activation reduces ischemia/reperfusion-induced metastasis in a murine model of hepatocellular carcinoma

Ischemia/reperfusion (I/R) injury during liver resection or transplantation for the treatment of hepatocellular carcinoma (HCC) may increase the risk of metastasis. Peroxisome proliferator-activated receptor-γ (PPARγ) activation has been observed to exert a protective effect against hepatic I/R injury. However, whether PPARγ activation exerts a protective effect against I/R-associated liver metastasis remains unknown. Therefore, the present study aimed to investigate the effects of the PPAR agonist rosiglitazone and the specific PPARγ antagonist GW9662 on tumor metastasis following hepatic I/R. An experimental mouse model of hepatic I/R-induced HCC metastasis was designed in order to determine the effects of I/R on tumor metastasis in the liver. Four groups were established: Sham, control (I/R), rosiglitazone (Ro) and rosiglitazone with GW9662 (Ro + GW) groups. In the latter two groups, the treatments were administered intravenously 1 h prior to the induction of ischemia. Tumor load was measured 12 days after the procedure. Furthermore, tissue analyses were conducted to determine the expression levels of alanine aminotransferase, myeloperoxidase (MPO), matrix metalloproteinase (MMP)-9, vascular cell adhesion molecule (VCAM)-1, nuclear factor (NF)-κB and PPARγ. Rosiglitazone pretreatment appeared to significantly mitigate hepatic I/R injury, as indicated by serological and histological analysis. The levels of VCAM-1, MPO and MMP-9 expression in the Ro group were significantly reduced at 8 h following ischemia compared with those in the control and Ro + GW groups. In addition, rosiglitazone inhibited the I/R-induced activation of NF-κB, and GW9662 attenuated the inhibitory effect. To the best of our knowledge, the present study is the first to report on the expression and the functional roles of PPARγ in I/R-associated metastasis. Short-term treatment of mice with rosiglitazone, a potent PPARγ agonist, confers protective effects against hepatic I/R-associated metastasis. Thus, PPARγ may be a potential therapeutic target for the protection of the liver against I/R-associated metastasis.

Process of hepatic metastasis from pancreatic cancer: biology with clinical significance

PURPOSE

Pancreatic cancer shows a remarkable preference for the liver to establish secondary tumors. Selective metastasis to the liver is attributed to the development of potential microenvironment for the survival of pancreatic cancer cells. This review aims to provide a full understanding of the hepatic metastatic process from circulating pancreatic cancer cells to their settlement in the liver, serving as a basic theory for efficient prediction and treatment of metastatic diseases.

METHODS

A systematic search of relevant original articles and reviews was performed on PubMed, EMBASE and Cochrane Library for the purpose of this review.

RESULTS

Three interrelated phases are delineated as the contributions of the interaction between pancreatic cancer cells and the liver to hepatic metastasis process. Chemotaxis of disseminated pancreatic cancer cells and simultaneous defensive formation of platelets or neutrophils facilitate specific metastasis toward the liver. Remodeling of extracellular matrix and stromal cells in hepatic lobules and angiogenesis induced by proangiogenic factors support the survival and growth of clinical micrometastasis colonizing the liver. The bimodal role of the immune system or prevalence of cancer cells over the immune system makes metastatic progression successfully proceed from micrometastasis to macrometastasis.

CONCLUSIONS

Pancreatic cancer is an appropriate research object of cancer metastasis representing more than a straight cascade. If any of the successive or simultaneous phases, especially tumor-induced immunosuppression, is totally disrupted, hepatic metastasis will be temporarily under control or even cancelled forever. To shrink cancers on multiple fronts and prolong survival for patients, novel oral or intravenous anti-cancer agents covering one or different phases of metastatic pancreatic cancer are expected to be integrated into innovative strategies on the premise of safety and efficacious biostability.

Preserving hepatic artery flow during portal triad blood inflow occlusion reduces the outgrowth of hepatocarcinoma in mice after ischemia-reperfusion

AIM

To investigate the effect of different hepatic vascular occlusion maneuvers on the growth of hepatocarcinoma after liver ischemia-reperfusion (I/R) injury.

METHODS

A mice hepatocarcinoma model was established by portal vein injection of H22 hepatoma cells. After 3 days, the mice underwent sham operation, occlusion of portal triad (OPT), portal vein (OPV), or intermittent clamping (INT) operation. The hepatic I/R injury, pathological changes, hepatic replacement area, proliferative cell nuclear antigen expression, and extracellular signal-regulated kinase (ERK) 1/2 activation were assessed 5 days after reperfusion.

RESULTS

Alanine aminotransferase and aspartate aminotransferase levels in the OPV group were significantly lower than those in the OPT and INT groups at 24 h after reperfusion. The hepatic injury of clamped liver lobes in the OPV group, represented by histopathological alterations and myeloperoxidase activity, was much slighter than that in the OPT and INT groups. The values of hepatic replacement area in the sham operation, OPT, OPV, and INT groups were 7.661 2.55%, 35.61 1 4.23%, 9.02 1 3.01%, and 19.95 1 4.10%, respectively. Proliferative cell nuclear antigen expression and ERK1/2 activation of tumor cells were the highest in the OPT group, and the lowest in the OPV and INT groups.

CONCLUSION

Preserving hepatic artery flow during portal triad blood inflow occlusion substantially inhibits the outgrowth of hepatocarcinoma via attenuating hepatic I/R injury in a murine liver tumor model. These results suggest a better prevention of hepatic tumor outgrowth after hepatectomy by using the selective portal vein clamping method in liver cancer patients.

Stimuli-induced organ-specific injury enhancement of organotropic metastasis in a spatiotemporal regulation

The relationship between inflammation and tumorigenesis has been established. Recently, inflammation is also reported to be a drive force for cancer metastasis. Further evidences show that various stimuli directly induced-injury in a specific organ can also promote metastasis in this organ, which include epidemiological reports, clinical series and experimental studies. Each type of cancer has preferential sites for metastasis, which is also due to inflammatory factors that are released by primary cancer to act on these sites and indirectly induce injuries on them. Host factors such as stress,fever can also influence distant metastasis in a specific site through stimulation of immune and inflammatory effects. The five aspects support an idea that specific-organ injury directly induced by various stimuli or indirectly induced by primary tumor or host factors activation of proinflammatory modulators can promote metastasis in this organ through a spatiotemporal regulation, which has important implications for personalized prediction, prevention and management of cancer metastasis.

Increased E-selectin in hepatic ischemia-reperfusion injury mediates liver metastasis of pancreatic cancer

Several recent studies have reported that selectins are produced during ischemia-reperfusion injury, and that selectin ligands play an important role in cell binding to the endothelium and in liver metastasis. Portal clamping during pancreaticoduodenectomy with vessel resection for pancreatic head cancer causes hepatic ischemia-reperfusion injury, which might promote liver metastasis. We investigated the liver colonization of pancreatic cancer cells under hepatic ischemia-reperfusion and examined the involvement of E-selectin and its ligands. A human pancreatic cancer cell line (Capan-1) was injected into the spleen of mice after hepatic ischemia-reperfusion (I/R group). In addition, to investigate the effect of an anti-E-selectin antibody on liver colonization in the IR group, mice received an intraperitoneal injection of the anti-E-selectin antibody following hepatic ischemia-reperfusion and tumor inoculation (IR+Ab group). Four weeks later, mice were sacrificed and the number of tumor nodules on the liver was compared to mice without hepatic ischemia-reperfusion (control group). The incidence of liver metastasis in the I/R group was significantly higher (16 of 20, 80%) than that in the control group (6 of 20, 30%) (P<0.01). Moreover, mice in the I/R group had significantly more tumor nodules compared to those in the control group (median, 9.9 vs. 2.7 nodules) (P<0.01). In the I/R+Ab group, only 2 of 5 (40%) mice developed liver metastases. RT-PCR and southern blotting of the liver extracts showed that the expression of IL-1 and E-selectin mRNA after hepatic ischemia-reperfusion was significantly higher than the basal levels. Hepatic ischemia-reperfusion increases liver metastases and E-selectin expression in pancreatic cancer. These results suggest that E-selectin produced due to hepatic ischemia-reperfusion is involved in liver metastasis.

Inhibitory CpG sequences reduced ischemia/reperfusion-induced hepatic metastases of liver tumor in a murine model

BACKGROUND

It is reported that hepatic ischemia/reperfusion (I/R) during hepatectomy accelerates liver tumor growth. Hepatic I/R induces inflammation cytokines, which can accelerate the outgrowth of liver tumor. Inhibitory CpG sequence (iCpG) is an inhibitor of TLR9, which plays an important role in hepatic I/R. The aim of this study was to examine whether iCpG could prevent hepatic I/R-induced metastases of the liver tumor.

MATERIALS AND METHODS

A murine tumor model that underwent partial hepatic I/R or sham operation was treated with iCpG or control DNA sequence (Ctrl ODN). Tumor growth and metastases were observed on day 14 after surgery; Endothelial leukocyte adhesion molecules such as E-selectin and intracellular adhesion molecule-1 (ICAM-1) protein expression were measured 24 h after reperfusion by Western blotting; E-selectin and ICAM-1 mRNA expression in hepatic tissue was measured 2 h after reperfusion by RT-PCR; NF-κB activity in hepatic tissue was measured 2 h after reperfusion by electrophoretic gel mobility shift assay.

RESULTS

The tumor growth in the mice subjected to hepatic I/R was remarkably stimulated when compared with the mice subjected to laparotomy alone. The iCpG had no significant inhibitory effect on tumor growth in sham-operated mice subjected to tumor. However, iCpG could reduce the tumor growth and inhibit the activation of NF-κB and downregulate the E-selectin and ICAM-1 mRNA and protein in the mice with tumor subjected to I/R.

CONCLUSIONS

ICpG might reduce I/R-induced hepatic metastases of liver tumor cells by inhibiting NF-κB expression and downregulating the adhesive molecules, such as E-selectin and ICAM-1.

Small-for-size liver graft injury--impact on tumor behavior

The success of liver transplantation has led to an ever-increasing demand for liver grafts. Since the first successful living donor liver transplantation, this surgical innovation has been well established in children and has significantly relieved the crisis of donor organ shortage for children. However, the extension of living donor liver transplantation to adult recipients is limited by the graft volume. The major concern of adult-to-adult living donor liver transplantation is the adequate graft that can be harvested from a living donor. Small-for-size graft injury is frequently observed. To develop novel effective treatments attenuating small-for-size liver graft injury during living donor liver transplantation, it is important to explore the precise mechanism of acute phase small-for-size graft damage. Recently, a number of clinical studies and animal experiments have been conducted to investigate the possible key issues on acute phase small-for-size liver graft injury, such as mechanical injury from shear stress, subsequent inflammatory responses, and imbalance of vasoregulatory factors. This review focuses on the mechanism of small-for-size liver graft injury based on the number of clinical and experimental studies. The latest research findings of the significance of acute phase liver graft injury on late phase tumor recurrence and metastasis are also addressed.

Use of bioluminescence imaging to detect enhanced hepatic and systemic tumor growth following partial hepatectomy in mice

BACKGROUND

The impact of partial hepatectomy on intra-hepatic and distant tumor growth is a matter of controversy. Utilizing a highly sensitive tumor imaging strategy, we sought to demonstrate whether this growth-acceleration occurs, and to develop an animal model with which to investigate potential therapeutic strategies.

METHODS

Mice bearing constitutively-active luciferase-expressing tumor cells were subjected to either 70% partial hepatectomy (PH; n=10) or a sham operation (n=11). Mice were sacrificed 14 days later and remnant livers (or anatomic equivalents in the control group) and lungs harvested for bioluminescence detection.

RESULTS

Remnant liver weights were significantly increased in PH compared to equivalent lobes in sham-operated animals (t-test; p=0.005). Tumor burden as measured by bioluminescence was significantly higher in both liver and lung specimens in the PH group (Wilcoxon's Rank Sum test; p=0.01 and 0.004, respectively).

CONCLUSIONS

Following PH, enhanced metastatic growth was depicted regionally and systemically with bioluminescence imaging providing an objective measure of tumor burden. This preclinical model can help to identify adjuvant therapies that can influence both tumor growth and liver regeneration.

Experimental study on transarterial administration of GRGDSP combined with transarterial chemoembolization in rats with hepatic carcinoma

PURPOSE

To evaluate the effects of transarterial administration of an integrin antagonist, GRGDSP (Gly-Arg-Gly-Asp-Ser-Pro), combined with transarterial chemoembolization (TACE) to treat hepatic carcinoma in rats.

METHODS

Walker-256 tumor was implanted beneath the liver capsule in 26 Wistar rats. Animal subjects were assigned to groups based on which treatment was injected into the hepatic artery: group A, GRGDSP + TACE; group B, TACE alone; and group C, normal saline. Magnetic resonance imaging (MRI), tumor pathology, and immunohistochemistry were performed to assess each treatment.

RESULTS

The ratios of the post-treatment to pretreatment tumor volumes (V2/V1) in groups A, B, and C were 4.42 +/- 0.48, 6.98 +/- 1.09, and 13.00 +/- 1.68, respectively. The metastatic potential of the tumors was assessed by tumor cell nest counts, which were 5.00 +/- 1.25, 6.63 +/- 1.60, and 7.22 +/- 1.92 in groups A, B, and C, respectively. Microvessel density (MVD) was quantified by measuring von Willebrand factor density values, which were 0.18 +/- 0.02, 0.22 +/- 0.02, and 0.23 +/- 0.02 in groups A, B, and C, respectively.

CONCLUSIONS

Transarterial infusion of GRGDSP combined with TACE noticeably inhibited the growth of hepatic carcinoma and intrahepatic metastases in rats.

Warm hepatic ischemia-reperfusion promotes growth of colorectal carcinoma micrometastases in mouse liver via matrix metalloproteinase-9 induction

Surgical resection remains the best treatment for colorectal metastases isolated to the liver; however, 5-year survival rates following liver resection are only 40% to 50%, with liver recurrence being a significant reason for treatment failure. The ischemia-reperfusion (I/R) injury incurred during liver surgery can lead to cellular dysfunction and elevations in proinflammatory cytokines and matrix metalloproteinases (MMP). In rodents, I/R injury to the liver has been shown to accelerate the outgrowth of implanted tumors. The mechanism for increased tumor growth in the setting of liver I/R injury is unknown. To investigate the effect of I/R on tumor growth, an experimental model was used whereby small hepatic metastases form after 28 days. Mice subjected to 30 min of 70% liver ischemia at the time of tumor inoculation had significantly larger tumor number and volume, and had elevated MMP9 serum and liver tissue MMP9 as evidenced by zymography and quantitative real-time PCR. Mice treated with doxycycline, a broad-spectrum MMP inhibitor, had reduced MMP9 levels and significantly smaller tumor number and volume in the liver. MMP9-null mice were used to determine if the effects of doxycycline were due to the absence of stromal-derived MMP9. The MMP9-null mice, with or without doxycycline treatment, had reduced tumor number and volume that was equivalent to wild-type mice treated with doxycycline. These findings indicate that hepatic I/R-induced elevations in MMP9 contribute to the growth of metastatic colorectal carcinoma in the liver and that postresection MMP9 inhibition may be clinically beneficial in preventing recurrence following hepatic surgery.

Antithrombin reduces reperfusion-induced hepatic metastasis of colon cancer cells

AIM: To examine whether antithrombin (AT) could prevent hepatic ischemia/reperfusion (I/R)-induced hepatic metastasis by inhibiting tumor necrosis factor (TNF)-α-induced expression of E-selectin in rats.

METHODS: Hepatic I/R was induced in rats and mice by clamping the left branches of the portal vein and the hepatic artery. Cancer cells were injected intrasplenically. The number of metastatic nodules was counted on day 7 after I/R. TNF-α and E-selectin mRNA in hepatic tissue, serum fibrinogen degradation products and hepatic tissue levels of 6-keto-PGF_1α, a stable metabolite of PGI₂, were measured.

RESULTS: AT inhibited increases in hepatic metastasis of tumor cells and hepatic tissue mRNA levels of TNF-α and E-selectin in animals subjected to hepatic I/R. Argatroban, a thrombin inhibitor, did not suppress any of these changes. Both AT and argatroban inhibited I/R-induced coagulation abnormalities. I/R-induced increases of hepatic tissue levels of 6-keto-PGF_1α were significantly enhanced by AT. Pretreatment with indomethacin completely reversed the effects of AT. Administration of OP-2507, a stable PGI₂ analog, showed effects similar to those of AT in this model. Hepatic metastasis in congenital AT-deficient mice subjected to hepatic I/R was significantly increased compared to that observed in wild-type mice. Administration of AT significantly reduced the number of hepatic metastases in congenital AT-deficient mice.

CONCLUSION: AT might reduce I/R-induced hepatic metastasis of colon cancer cells by inhibiting TNF-α-induced expression of E-selectin through an increase in the endothelial production of PGI₂. These findings also raise the possibility that AT might prevent hepatic metastasis of tumor cells if administered during the resection of liver tumors.

Hepatic tumor growth: target for angiogenesis inhibition?

Pathologic angiogenesis induced by a tumor is essential for its survival. The promise of tumor inhibition by targeting angiogenesis over the past several years has translated into numerous ongoing clinical trials. Recently, in a phase III trial involving patients with metastatic colorectal cancer, Bevacizumab (Genentech, Inc, San Francisco, CA), a recombinant humanized monoclonal antibody against vascular endothelial growth factor used in conjunction with standard chemotherapy was shown to increase survival, progression-free survival, response rate, and duration of response compared to chemotherapy alone. Thus far, duration of the increased response remains less than 6 months. The majority of deaths in patients with colorectal cancer are related to hepatic metastases. It is hoped that novel approaches directed at the complex interactions between tumor and microenvironment in the angiogenic process will strengthen the therapeutic armamentarium against hepatic malignancies.

Liver metastasis and ICAM-1 mRNA expression in the liver after carbon dioxide pneumoperitoneum in a murine model

BACKGROUND

Liver metastasis of colorectal malignancies is an important prognostic factor. Several studies have demonstrated that carbon dioxide (CO2) pneumoperitoneum enhances liver metastasis in animal models. Little is known about intercellular adhesion molecule-1 (ICAM-1) and tumor necrosis factor-alpha (TNF-(alpha) mRNA expression in the liver after CO2 pneumoperitoneum.

METHODS

Forty-five male BALB/c mice were randomly divided into three groups after intra-splenic tumor cell (colon 26) inoculation and the following procedures were performed: CO2 pneumoperitoneum (n = 15), open laparotomy (n = 15), and anesthesia alone (n = 15). On day 7 after each procedure, the livers were excised and the number and diameter of the tumor nodules and the cancer index score were determined. Another 90 male BALB/c mice were randomly divided into three groups as described above, and they underwent each procedure (n = 30 each). After each procedure, the livers were excised on days 0, 1, 3, and ICAM-1 and TNF-alpha mRNA expression were examined by real-time RT-PCR using SYBR Green I.

RESULTS

The number of tumor nodules and the cancer index score were larger in the CO2 pneumoperitoneum group than in the control group (p < 0.05). The mean diameter of the tumor nodules was not different among the three groups. The expression of ICAM-1 in the CO2 pneumoperitoneum group was higher than that in the other groups on day 1 (p < 0.05), and the TNF-alpha mRNA was higher than that in the control group on day 1 (p < 0.05).

CONCLUSIONS

CO2 pneumoperitoneum enhances liver metastasis compared with anesthesia alone, and ICAM-1 expression in the liver after the pneumoperitoneum plays an important role in establishing liver metastasis in a murine model.

Intermittent hepatic ischemia-reperfusion minimizes liver metastasis in rats

BACKGROUND

Surgical stresses, including hepatic ischemia-reperfusion (I/R), promote cancer growth and metastasis. We have reported that continuous hepatic I/R increases liver damage and promoted liver metastasis from colon cancer, whereas intermittent I/R causes less liver damage. We therefore examined whether intermittent I/R could reduce liver metastasis in a rat model.

MATERIALS AND METHODS

Adult male Fischer rats was divided between three groups: group A (control), which received laparotomy for 120 min with no liver ischemia; group B (continuous I/R), which received 60 min of 70% partial liver ischemia followed by 60 min of reperfusion; and group C (intermittent I/R), which received 15 min of 70% ischemia and 15 min of reperfusion, repeated four times. Just before closing the abdomen, all animals were inoculated intrasplenically with rat colon adenocarcinoma cells (RCN-H4). Tumor nodules on the liver surface were counted 3 weeks later. In addition, expression of E-selectin mRNA in liver was examined at 1, 3, and 6 h after completing I/R by a reverse transcription-polymerase chain reaction.

RESULTS

Continuous I/R (B) greatly promoted liver metastasis in both ischemic and nonischemic liver lobes, whereas intermittent I/R (C) showed significantly fewer metastasis than group B in both lobes. Significantly less E-selectin mRNA was expressed in group C than in group B.

CONCLUSIONS

Intermittent I/R limits expression of E-selectin mRNA and liver metastasis. Intermittent hepatic I/R is less stressful than continuous I/R, minimizing liver metastasis by colon cancer cells through avoidance of E-selectin up-regulation.

Hepatic ischemia-reperfusion promotes liver metastasis of colon cancer

BACKGROUND

The effects of hepatic ischemia/reperfusion (I/R) on liver metastasis have not been fully examined. We examined hepatic I/R and liver metastasis of colorectal cancer in a rat model; we also quantitated expression of E-selectin (ELAM-1) mRNA after I/R.

MATERIALS AND METHODS

Rats underwent 30 or 60 min of 70% partial hepatic ischemia. After 60 min of reperfusion, rat colon adenocarcinoma cells (RCN-H4) were inoculated intrasplenically. The number of tumor nodules on the liver surface was determined 3 weeks later. Expression of E-selectin mRNA was determined at 1, 3, and 6 h after ischemia by quantitative RT-PCR.

RESULTS

Hepatic I/R promoted liver metastasis of RCN-H4 and induced the expression of E-selectin mRNA in both clamped and unclamped liver lobes. The number of tumor nodules and the expression of E-selectin mRNA after 60 min of ischemia was greater than that after 30 min.

CONCLUSIONS

Hepatic I/R, especially with a long duration of ischemia, induces expression of E-selectin and promotes liver metastasis of colon cancer in rats.

Carbohydrate-binding proteins in cancer, and their ligands as therapeutic agents

Experimental evidence directly implicates complex carbohydrates in recognition processes, including adhesion between cells, adhesion of cells to the extracellular matrix, and specific recognition of cells by one another. In addition, carbohydrates are recognized as differentiation markers and as antigenic determinants. Lectins are nonenzymatic proteins present in plants and animals, which preferentially bind to specific carbohydrate structures and play an important role in cell recognition. Modified carbohydrates and oligosaccharides have the ability to interfere with carbohydrate-protein interactions and therefore, inhibit the cell-cell recognition and adhesion processes, which play an important role in cancer growth and progression. Carbohydrate ligands therefore, are candidates to play important roles in cancer therapeutics.