Colorectal Cancer Progression Is Potently Reduced by a Glucose-Free, High-Protein Diet: Comparison to Anti-EGFR Therapy

Simple Summary

To study the interplay between nutrition and intestinal metabolism in the context of colitis-driven colorectal carcinoma (CRC), we here investigated a nutritional therapy strategy in the presence or absence of EGFR-directed antibody therapy in mice to treat established colitis-driven CRCs in vivo. After CRC development, mice were fed a control diet or an isoenergetic glucose-free high-protein (GFHP) diet in the presence or absence of EGFR-directed antibody therapy. The GFHP diet was accompanied by a metabolic shift of the mice towards lower glycolysis activity. Both, GFHP diet or anti-EGFR antibody treatment, improved tumor differentiation and anti-tumor immune response, resulting in an efficient reduction of colonic tumor burden.

Abstract

To enable rapid proliferation, colorectal tumor cells up-regulate epidermal growth factor receptor (EGFR) signaling and aerobic glycolysis, resulting in substantial lactate release into the tumor microenvironment and impaired anti-tumor immune responses. We hypothesized that a nutritional intervention designed to reduce aerobic glycolysis may boost the EGFR-directed antibody (Ab)-based therapy of pre-existing colitis-driven colorectal carcinoma (CRC). CRC development was induced by azoxymethane (AOM) and dextran sodium sulfate (DSS) administration to C57BL/6 mice. AOM/DSS-treated mice were fed a glucose-free, high-protein diet (GFHPD) or an isoenergetic control diet (CD) in the presence or absence of an i.p. injection of an anti-EGFR mIgG2a or respective controls. AOM/DSS-treated mice on a GFHPD displayed a reduced systemic glucose metabolism associated with reduced oxidative phosphorylation (OXPHOS) complex IV expression and diminished tumor loads. Comparable but not additive to an anti-EGFR-Ab therapy, the GFHPD was accompanied by enhanced tumoral goblet cell differentiation and decreased colonic PD-L1 and splenic CD3ε, as well as PD-1 immune checkpoint expression. In vitro, glucose-free, high-amino acid culture conditions reduced proliferation but improved goblet cell differentiation of murine and human CRC cell lines MC-38 and HT29-MTX in combination with down-regulation of PD-L1 expression. We here found GFHPD to systemically dampen glycolysis activity, thereby reducing CRC progression with a similar efficacy to EGFR-directed antibody therapy.

[Establishment of animal models of epidermal growth factor receptor inhibitor-related rashes]

OBJECTIVE

To establish animal models epidermal growth factor receptor inhibitor-related skin rashes using cetuximab, gefitinib or erlotinib.

OBJECTIVE

Female SCID mice were randomly divided into blank control group and high-, moderate-, and low-dose cetuximab groups. The mice in control group received intraperitoneal injection of saline, and those in the 3 cetuximab groups were injected with 80, 40, and 20 mg/kg cetuximab (3 times a week for 4 weeks), respectively. The general skin appearance and skin pathologies of the mice were observed. Female BN rats were randomly divided into blank group, ovalbumin group, gefitinib group and erlotinib group, and in the latter 3 groups, the rats were given ovalbumin (1 mg), gefitinib (37.5 mg/kg), and erlotinib (23.5 mg/kg) by lavage once daily for 45 days, respectively. Skin pathologies of the rats were observed, and serum levels of TNF-α, IL-6 and other inflammatory factors were detected using ELISA.

OBJECTIVE

Intraperitoneal injection of cetuximab did not induce typical skin rashes, scabs or obvious skin inflammation in the mice. In female BN rats, lavage of gefitinib caused obvious skin rashes, scabs and exudation, and obvious inflammatory cell infiltration, keratinosis, spinous layer release and epidermal thickening were observed in the skin. No obvious skin inflammation were observed in the rats in the control, ovalbumin or erlotinib groups. While IgE (P=0.061) and TNF-α concentrations (P=0.057) did not differ significantly among the groups, serum levels of IL-6 was significantly higher in gefitinib group than in the blank control group (P=0.016) but similar between erlotinib group and the blank group (P=0.910).

OBJECTIVE

Intraperitoneal injection of cetuximab can not induce epidermal growth factor receptor inhibitor-related skin rashes in SCID mice. Lavage of gefitinib, but not erlotinib, can be used to establish models of epidermal growth factor receptor inhibitor-related rashes in BN rats.

Issues to be considered to address the future liver remnant prior to major hepatectomy

An accurate preoperative evaluation of the hepatic function and application of portal vein embolization in selected patients have helped improve the safety of major hepatectomy. In planning major hepatectomy, however, several issues remain to be addressed. The first is which cut-off values for serum total bilirubin level and prothrombin time should be used to define post-hepatectomy liver failure. Other issues include what minimum future liver remnant (FLR) volume is required; whether the total liver volume measured using computed tomography or the standard liver volume calculated based on the body surface area should be used to assess the adequacy of the FLR volume; whether there is a discrepancy between the FLR volume and function during the recovery period after portal vein embolization or hepatectomy; and how best the function of a specific FLR can be assessed. Various studies concerning these issues have been reported with controversial results. We should also be aware that different strategies and management are required for different types of liver damage, such as cirrhosis in hepatocellular carcinoma, cholangitis in biliary tract cancer, and chemotherapy-induced hepatic injury.

Bevacizumab Allows Preservation of Liver Function and its Regenerative Capacity after Major Hepatectomy

BACKGROUND

Parallel to the safety of liver resections, new chemotherapy drugs have emerged for the control of liver metastases. However, there is unclear evidence about the combination of intensive BVZ-therapy and extended resections. The main aim was to analyse the impact of Bevacizumab (BVZ) in terms of liver safety and tolerability in two experimental models: a basal-toxicity situation and after major hepatectomy.

METHODS

Eighty male-Wistar rats were grouped as toxicity analysis (sham-operated rats-OS-) and regeneration after- surgery analysis (hepatectomy rats-H-). Eight further subgroups were created according to sacrifice (6- hours-6h- or 24-hours-24h-) and dose (μg) of BVZ (none, 100, 200, 400). Several measurements were performed, including biochemical serum samples, histopathological analysis, cytokines (IL-6, TNF-α, TGF-β), oxidative-stress (GSH/GSSG, ATP), lipid-peroxidation (TBARS) and epidermal and vascular endothelium growth-factors (EGF and VEGF).

RESULTS

In the toxicity analysis, safe results with BVZ were observed, with no significant differences among the groups. A trend towards a lower oxidative status was observed in the OS 6 h-100, -200 and -400 versus the OS 6 h-none group. Similar results were observed in the hepatectomy model, with stable oxidative-stress-index and IL-6, TNF- α, and TGF- β levels. Despite higher lipid peroxidation status, overall regeneration was preserved. As expected, VEGF was almost undetectable in BVZ-treated groups after resection, but not in the non-resection group.

CONCLUSION

It was concluded that liver status was not impaired by BVZ even at the high-dose. Similarly, liver regeneration after extended hepatectomy in BVZ-treated animals was well-preserved. Extended liver resections may be encouraged in BVZ-treated patients due to its excellent tolerability and good liver regeneration status.

Liver surgery for metastatic colorectal cancer: the surgical oncologist perspective

Neoadjuvant/conversion chemotherapy has emerged as an indispensable tool to achieve resectability of initially unresectable metastatic colorectal cancer and improves oncological outcomes. In parallel, surgical strategy has adopted a more aggressive treatment approach to achieve complete tumor clearance. However, chemotherapy affects liver function and combined with extensive liver resection, morbidity has increased, thereby compromising oncological outcome. There is an imperative need for careful patient selection to optimize patient management. In this review, we discuss available evidence and indications for neoadjuvant treatment in the management of colorectal cancer liver metastases, on preoperative patient selection and identification of high-risk patients, potential treatment strategies to promote postoperative liver regeneration to avoid postoperative morbidity and potentially deleterious side effects of these therapies on tumor growth.

Antagonist antibodies to vascular endothelial growth factor receptor 2 (VEGFR-2) as anti-angiogenic agents

Interaction of numerous signaling pathways in endothelial and mesangial cells results in exquisite control of the process of physiological angiogenesis, with a central role played by vascular endothelial growth factor receptor 2 (VEGFR-2) and its cognate ligands. However, deregulated angiogenesis participates in numerous pathological processes. Excessive activation of VEGFR-2 has been found to mediate tissue-damaging vascular changes as well as the induction of blood vessel expansion to support the growth of solid tumors. Consequently, therapeutic intervention aimed at inhibiting the VEGFR-2 pathway has become a mainstay of treatment in cancer and retinal diseases. In this review, we introduce the concepts of physiological and pathological angiogenesis, the crucial role played by the VEGFR-2 pathway in these processes, and the various inhibitors of its activity that have entered the clinical practice. We primarily focus on the development of ramucirumab, the antagonist monoclonal antibody (mAb) that inhibits VEGFR-2 and has recently been approved for use in patients with gastric, colorectal, and lung cancers. We examine in-depth the pre-clinical studies using DC101, the mAb to mouse VEGFR-2, which provided a conceptual foundation for the role of VEGFR-2 in physiological and pathological angiogenesis. Finally, we discuss further clinical development of ramucirumab and the future of targeting the VEGF pathway for the treatment of cancer.

Impact of Bevacizumab on parenchymal damage and functional recovery of the liver in patients with colorectal liver metastases

Background

Little is known about the safety of the anti-VEGF antibody bevacizumab in patients undergoing resection for colorectal liver metastases (CLM). This meta-analysis evaluates the impact of bevacizumab on parenchymal damage and functional recovery in patients undergoing resection for CLM.

Methods

The Medline, Embase and Cochrane Library were systematically searched for studies on preoperative chemotherapy with and without bevacizumab prior to resection of CLM. Studies that reported histological and/or clinical outcomes were eligible for inclusion. Meta-analyses were performed using a random effects model.

Results

A total of 18 studies with a total sample size of 2430 patients (1050 patients with bevacizumab) were found. Meta-analyses showed a significant reduction in sinusoidal obstruction syndrome (SOS) (Odds ratio 0.50 [95 % confidence interval 0.37, 0.67]; p < 0.001; I² = 0 %) and hepatic fibrosis (0.61 [0.4, 0.86]; p = 0.004; I² = 7 %) after preoperative chemotherapy with bevacizumab. The reduced incidence of posthepatectomy liver failure in patients with bevacizumab treatment just failed to reach statistical significance (0.61 [0.34, 1.07]; p = 0.08 I² = 6 %). While there was no difference in perioperative morbidity and mortality, the incidence of wound complications was significantly increased in patients who received bevacizumab (1.81 [1.12, 2.91]; p = 0.02 I² = 4 %).

Conclusions

The combination of bevacizumab with cytotoxic chemotherapy is safe but increases the incidence of wound complications after resection of CLM. The reduction of SOS and hepatic fibrosis warrant further investigation and may explain the inverse association of bevacizumab administration and posthepatectomy liver failure.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2095-6) contains supplementary material, which is available to authorized users.

EGFR Signaling in Liver Diseases

The epidermal growth factor receptor (EGFR) is a transmembrane receptor tyrosine kinase that is activated by several ligands leading to the activation of diverse signaling pathways controlling mainly proliferation, differentiation, and survival. The EGFR signaling axis has been shown to play a key role during liver regeneration following acute and chronic liver damage, as well as in cirrhosis and hepatocellular carcinoma (HCC) highlighting the importance of the EGFR in the development of liver diseases. Despite the frequent overexpression of EGFR in human HCC, clinical studies with EGFR inhibitors have so far shown only modest results. Interestingly, a recent study has shown that in human HCC and in mouse HCC models the EGFR is upregulated in liver macrophages where it plays a tumor-promoting function. Thus, the role of EGFR in liver diseases appears to be more complex than what anticipated. Further studies are needed to improve the molecular understanding of the cell-specific signaling pathways that control disease development and progression to be able to develop better therapies targeting major components of the EGFR signaling network in selected cell types. In this review, we compiled the current knowledge of EGFR signaling in different models of liver damage and diseases, mainly derived from the analysis of HCC cell lines and genetically engineered mouse models (GEMMs).

Changes in Liver Volume Observed Following Sorafenib and Liver Radiation Therapy

PURPOSE

The purpose of this study was to quantify unexpected liver volume reductions in patients treated with sorafenib prior to and during liver radiation therapy (RT).

METHODS AND MATERIALS

Fifteen patients were treated in a phase 1 study of sorafenib for 1 week, followed by concurrent sorafenib-RT (in 6 fractions). Patients had either focal cancer (treated with stereotactic body RT [SBRT]) or diffuse disease (treated with whole-liver RT). Liver volumes were contoured and recorded at planning (day 0) from the exhale CT. After 1 week of sorafenib (day 8), RT image guidance at each fraction was performed using cone beam CT (CBCT). Planning liver contours were propagated and modified on the reconstructed exhale CBCT. This was repeated in 12 patients treated with SBRT alone without sorafenib. Three subsequent patients (2 sorafenib-RT and 1 non-sorafenib) were also assessed with multiphasic helical breath-hold CTs.

RESULTS

Liver volume reductions on CBCT were observed in the 15 sorafenib-RT patients (median decrease of 68 cc, P=.02) between day 0 and 8; greater in the focal (P=.025) versus diffuse (P=.52) cancer stratum. Seven patients (47%) had reductions larger than the 95% intraobserver contouring error. Liver reductions were also observed from multiphasic CTs in the 2 additional sorafenib-RT patients between days 0 and 8 (decreases of 232.5 cc and 331.7 cc, respectively) and not in the non-sorafenib patient (increase of 92 cc). There were no significant changes in liver volume between planning and first RT in 12 patients with focal cancer treated with SBRT alone (median increase, 4.8 cc, P=.86).

CONCLUSIONS

Liver volume reductions were observed after 7 days of sorafenib, prior to RT, most marked in patients with focal liver tumors, suggesting an effect of sorafenib on normal liver. Careful assessment of potential liver volume changes immediately prior to SBRT may be necessary in patients in sorafenib or other targeted therapies.

Potentially resectable metastatic colorectal cancer: an individualized approach to conversion therapy

Colorectal cancer is one of the most common cancers worldwide. In recent years, the survival of patients with metastatic disease has improved due to the developments in both medical and surgical care. Patients with technically unresectable metastatic disease could benefit from a multidisciplinary approach for their possible shift toward a technically resectable condition; the choice of the most effective systemic treatment is then crucial to allow conversion to resectability. Systemic conversion therapy may include chemotherapy agents' combinations (fluoropyrimidine, irinotecan and oxaliplatin), with or without targeted agents (cetuximab, panitumumab, bevacizumab). The choice of the best treatment option has to be evaluated by taking into account each patient's baseline characteristics, biological and pathological information and surgical strategy. In particular, the role of some biologic characteristics of the disease, namely the mutational status of EGFR-pathway oncogenes, is emerging as an important predictive factor of response to anti-EGFR targeted agents. Patients presenting with colorectal cancer metastases should be evaluated for multimodal management with curative intent as the appropriate chemotherapy regimen may induce tumor shrinkage, conversion to resectability and improved survival.

Volumetric analysis of remnant liver regeneration after major hepatectomy in bevacizumab-treated patients: a case-matched study in 82 patients

BACKGROUND

The objective was to determine the liver regeneration capacity and morbidity and mortality rates after major hepatectomy for colorectal metastases in patients having undergone bevacizumab-based chemotherapy (bev+).

PATIENTS AND METHODS

Between 2006 and 2011, 41 patients underwent major hepatectomy within 3 months of bevacizumab and were matched with 41 patients operated on following systemic chemotherapy without bevacizumab (bev-). The matching criteria were the following: number of courses of chemotherapy, chemotherapy-free interval, age, and type of hepatectomy. After measurements of remnant liver volume (RLV) preoperatively and at 1 month (RLV1M), volumetric gain was calculated as absolute (RLV1M-RLV) or relative regeneration [(RLV1M-RLV/RLV)]. Ninety-day morbidity was rated according to the Clavien-Dindo classification.

RESULTS

There were 21 right, 9 extended right, and 11 left hepatectomies in each group. Groups were comparable in terms of matching criteria, body mass index, American Society of Anesthesiologists score, and RLV. No mortalities were observed. There were no intergroup differences in overall morbidity (56% in bev+ vs 34.1%; P = 0.075) or postoperative liver failure. A severe complication occurred in 5 bev+ (4 eviscerations) and 4 bev- (bile leakages) (P = 0.95). The median hospital stay was similar in both groups as were the degrees of absolute and relative liver regeneration (143% in bev+ vs 114%; P = 0.20). Liver regeneration was not influenced by the type of hepatectomy, the number of courses of chemotherapy, or age more than 65 years.

CONCLUSIONS

In a methodologically robust trial in the largest cohort reported up to date, bevacizumab did not impair liver regeneration after major hepatectomy-even in elderly patients or those with high exposure to chemotherapy.

Hepatic arterial infusion but not systemic application of cetuximab in combination with oxaliplatin significantly reduces growth of CC531 colorectal rat liver metastases

PURPOSE

Systemic chemotherapy still represents the gold standard in the treatment of irresectable colorectal liver metastases. Modern anticancer agents like the monoclonal antibody cetuximab have improved the outcome of patients in clinical studies. As hepatic arterial infusion (HAI) is capable to potentially increase the anticancer effect of cytostatics, we herein studied whether HAI of cetuximab (CE) as a single agent or in combination with oxaliplatin (OX) exerts increased anticancer effects compared to the systemic application (SYS) of the drugs.

METHODS

WAG/Rij rats were randomized to eight groups and underwent 10 days after subcapsular hepatic tumor implantation either HAI or SYS of CE, OX, or the combination of both agents (CE + OX). Saline-treated animals served as controls. Tumor volume was measured at days 10 and 13 using three-dimensional ultrasound. On day 13, liver and tumor tissue was sampled for histological and immunohistochemical analysis.

RESULTS

In controls, the tumor volume significantly increased from day 10 to 13. Application of OX alone via HAI or SYS did not inhibit tumor growth compared to controls. SYS of CE or CE + OX did also not reduce tumor growth. In contrast, HAI of CE and CE + OX significantly inhibited tumor growth. HAI of CE significantly reduced tumor vascularization as measured by the number of platelet endothelial cell adhesion molecule-1-positive cells and significantly increased the number of apoptotic tumor cells as measured by the cellular caspase-3 expression.

CONCLUSION

HAI of CE and CE + OX reduces tumor growth of colorectal rat liver metastases involving the inhibition of angiogenesis and induction of tumor cell apoptosis.

Neoadjuvant bevacizumab persistently inactivates VEGF at the time of surgery despite preoperative cessation

BACKGROUND

When anti-VEGF (vascular endothelial growth factor) antibody bevacizumab is applied in neoadjuvant treatment of colorectal cancer patients with liver metastasis, 5-6 weeks between last bevacizumab dose and liver resection are currently recommended to avoid complications in wound and liver regeneration. In this context, we aimed to determine whether VEGF is inactivated by bevacizumab at the time of surgery.

METHODS

Fifty colorectal cancer patients with liver metastases received neoadjuvant chemotherapy ± bevacizumab supplementation. The last dose of bevacizumab was administered 6 weeks before surgery. Plasma, subcutaneous and intraabdominal wound fluid were analysed for VEGF content before and after liver resection (day 1-3). Immunoprecipitation was applied to determine the amount of bevacizumab-bound VEGF.

RESULTS

Bevacizumab-treated individuals showed no increase in perioperative complications. During the entire monitoring period, plasma VEGF was inactivated by bevacizumab. In wound fluid, VEGF was also completely bound by bevacizumab and was remarkably low compared with the control chemotherapy group.

CONCLUSION

These data document that following a cessation time of 6 weeks, bevacizumab is fully active and blocks circulating and local VEGF at the time of liver resection. However, despite effective VEGF inactivation no increase in perioperative morbidity is recorded suggesting that VEGF activity is not essential in the immediate postoperative recovery period.

Normal tissues toxicities triggered by combined anti-angiogenic and radiation therapies: hurdles might be ahead

BACKGROUND

Combined-modality therapy is a promising approach to improve the therapeutic index of radiotherapy. However, these improvements could come at the cost of increased toxicities. Clinical trials evaluating anti-tumour efficacy of bevacizumab combined with radiotherapy have encountered unexpected side effects. This study is the first systematic evaluation of normal tissue toxicity triggered by anti-angiogenic agents combined with radiation therapy in mice.

METHODS

Effect of a mouse anti-VEGF antibody was monitored on acute toxicity studying radiation-induced intestinal ulceration (12 Gy TBI); on subacute toxicity using a model of oral mucositis (16.5 Gy); on late radiation injuries by monitoring lung fibrosis (bleomycin and 19 Gy).

RESULTS

Combination of irradiation with anti-VEGF antibody enhanced intestinal damages with severe epithelial ulcerations, had no adverse impact on oral mucositis and dramatically worsened the fibrotic picture induced by bleomycin and irradiation to the lung.

INTERPRETATION

These reports bring to light the important questions about safety and underscore the need for appropriate preclinical modelling of the impact on normal tissues of novel drug-radiation regimens. Our findings also highlight the complexity of anti-VEGF action, which could in defined conditions exert tissue-specific protection. The findings indicate that the combination of targeted drugs with radiotherapy should be approached with caution.

Concordance of preclinical and clinical pharmacology and toxicology of therapeutic monoclonal antibodies and fusion proteins: cell surface targets

Monoclonal antibodies (mAbs) and fusion proteins directed towards cell surface targets make an important contribution to the treatment of disease. The purpose of this review was to correlate the clinical and preclinical data on the 15 currently approved mAbs and fusion proteins targeted to the cell surface. The principal sources used to gather data were: the peer reviewed Literature; European Medicines Agency 'Scientific Discussions'; and the US Food and Drug Administration 'Pharmacology/Toxicology Reviews' and package inserts (United States Prescribing Information). Data on the 15 approved biopharmaceuticals were included: abatacept; abciximab; alefacept; alemtuzumab; basiliximab; cetuximab; daclizumab; efalizumab; ipilimumab; muromonab; natalizumab; panitumumab; rituximab; tocilizumab; and trastuzumab. For statistical analysis of concordance, data from these 15 were combined with data on the approved mAbs and fusion proteins directed towards soluble targets. Good concordance with human pharmacodynamics was found for mice receiving surrogates or non-human primates (NHPs) receiving the human pharmaceutical. In contrast, there was poor concordance for human pharmacodynamics in genetically deficient mice and for human adverse effects in all three test systems. No evidence that NHPs have superior predictive value was found.

The effects of sorafenib on liver regeneration in a model of partial hepatectomy

BACKGROUND

Sorafenib is currently approved for advanced hepatocellular carcinoma (HCC) and is presently being studied as an adjuvant treatment for HCC following resection. The effects of sorafenib on liver regeneration have not been clearly defined. Our objective was to identify the effects of sorafenib on liver regeneration in a murine partial hepatectomy (PH) model.

MATERIALS AND METHODS

We performed PH in C57Bl/6 mice treated with a range of sorafenib doses with assessments at several time points. Liver sinusoidal endothelial cells (LSEC) and hepatocyte DNA synthesis and proliferation were assessed with 5-bromo-2'-deoxyuridine (BrdU) and Ki67 by flow cytometry and immunohistochemistry.

RESULTS

Treatment with sorafenib did not result in any deaths following PH. When we measured BrdU uptake to assess DNA synthesis, there was a statistically significant increase at 48 h post-PH for nonfibrotic LSEC following treatment with 60 mg/kg of sorafenib. However, BrdU and Ki67 staining among LSEC and hepatocytes was not significantly affected by sorafenib at any of the other doses or time points. BrdU and Ki67 flow cytometry data correlated with immunohistochemistry findings and postoperative liver weights.

CONCLUSION

In a murine PH model, sorafenib did not alter the repair response of normal or fibrotic livers following PH as measured by changes in liver weight, DNA synthesis, and cellular proliferation. These findings suggest sorafenib administered following hepatic resection does not impair liver regeneration.

Treatment of colorectal liver metastases

Colorectal cancer (CRC) is the third most common cancer in the word. Liver metastasis is the most common site of colorectal metastases. The prognosis of resectable colorectal liver metastases (CRLM) was improved in the recent years with the consideration of chemotherapy and surgical resection as part of the multidisciplinary management of the disease; the current 5-year survival rates after resection of liver metastases are 25% to 40%. Resectable synchronous or metachronous liver metastases should be treated with perioperative chemotherapy based on three months of FOLFOX4 (5-fluorouracil [5FU], folinic acid [LV], and oxaliplatin) chemotherapy before surgery and three months after surgery. In the case of primary surgery, pseudo-adjuvant chemotherapy for 6 months, based on 5FU/LV, FOLFOX4, XELOX (capecitabine and oxaliplatin) or FOLFIRI (5FU/LV and irinotecan), should be indicated. In potentially resectable disease, primary chemotherapy based on more intensive regimens such as FOLFIRINOX (5FU/LV, irinotecan and oxaliplatin) should be considered to enhance the chance of cure. The palliative chemotherapy based on FOLFIRI, or FOLFOX4/XELOX with or without targeted therapies, is the mainstay treatment of unresectable disease. This review would provide additional insight into the problem of optimal integration of chemotherapy and surgery in the management of CRLM.

Autocrine-controlled formation and function of tissue-like aggregates by primary hepatocytes in micropatterned hydrogel arrays

The liver carries out a variety of essential functions regulated in part by autocrine signaling, including hepatocyte-produced growth factors and extracellular matrix (ECM). The local concentrations of autocrine factors are governed by a balance between receptor-mediated binding at the cell surface and diffusion into the local matrix and are thus expected to be influenced by the dimensionality of the cell culture environment. To investigate the role of growth factor and ECM-modulated autocrine signaling in maintaining appropriate primary hepatocyte survival, metabolic functions, and polarity, we created three-dimensional cultures of defined geometry using micropatterned semisynthetic polyethylene glycol-fibrinogen hydrogels to provide a mechanically compliant, nonadhesive material platform that could be modified by cell-secreted factors. We found that in the absence of exogenous peptide growth factors or ECM, hepatocytes retain the epidermal growth factor (EGF) receptor ligands (EGF and transforming growth factor-α) and the proto-oncogenic mesenchymal epithelial transition factor (c-MET) ligand hepatocyte growth factor (HGF), along with fibronectin. Further, hepatocytes cultured in this three-dimensional microenvironment maintained high levels of liver-specific functions over the 10-day culture period. Function-blocking inhibitors of α5β1 or EGF receptor dramatically reduced cell viability and function, suggesting that signaling by both these receptors is needed for in vitro survival and function of hepatocytes in the absence of other exogenous signals.

Effect of sorafenib on murine liver regeneration

Hepatocellular carcinoma (HCC) is a common cause of cancer-related death. Sorafenib prolongs survival of patients with advanced disease and is approved for the systemic treatment of unresectable HCC. It possesses antiangiogenic and antiproliferative properties by way of inhibition of the receptor tyrosine kinases vascular endothelial growth factor receptor 2 (VEGFR-2) and platelet-derived growth factor receptor-beta 1/2 (PDGFR-β) and the kinase RAF. Sorafenib represents a candidate compound for adjuvant therapy in HCC patients. The aim of our study was to investigate whether sorafenib affects liver regeneration. C57BL6 mice received sorafenib orally at 30 mg/kg/day or its vehicle either for 14 days until the day before hepatectomy or starting the day after surgery or both. Animals were sacrificed 24, 72, and 120 hours after hepatectomy. Liver regeneration was calculated as a percent of initial liver weight. Bromodeoxyuridine (BrdU) incorporation and phospho-extracellular signal-regulated kinase (pERK1/2) were determined by immunohistochemistry on liver sections. VEGF-A, PDGF-BB, and hepatocyte growth factor (HGF) levels were measured in liver tissue homogenates. Histological analysis of scar tissue was performed. Treatment stopped 1 day before surgery had no impact on liver regeneration. Continuous sorafenib treatment and treatment started 1 day after surgery had statistically significant effects on liver regeneration at 120 hours compared to vehicle-treated control animals (72% ± 12 versus control 88% ± 15 and 70% ± 13 versus control 86% ± 5 at 120 hours, both P ≤ 0.02). BrdU incorporation showed decreased numbers of positive nuclei in both groups receiving sorafenib after surgery. Phospho-ERK levels were reduced in sorafenib-treated animals. An increase of VEGF-A levels was observed in mice receiving sorafenib. Wound-healing complications were observed in animals receiving sorafenib after surgery and confirmed on histological sections.

CONCLUSION

This preclinical study shows that sorafenib did not impact on liver regeneration when ceased before surgery; however, administration after hepatectomy affected late liver regeneration.

Biologic modulation of chemotherapy in patients with hepatic colorectal metastases: the role of anti-VEGF and anti-EGFR antibodies

In the treatment of metastatic colorectal cancer, the subset of patients with liver-only metastases shows the greatest promise for prolonged survival and cure. Advances in surgery and medical treatment have encouraged multimodality treatment strategies and therefore require a true multidisciplinary approach. The current standard of care includes peri-operative chemotherapy and surgery. The new era of biologically targeted therapy requires an in-depth look at the possible efficacy and risks of adding these agents to the treatment protocol.

Inductive angiocrine signals from sinusoidal endothelium are required for liver regeneration

During embryogenesis, endothelial cells induce organogenesis before the development of circulation. These findings suggest that endothelial cells not only form passive conduits to deliver nutrients and oxygen, but also establish an instructive vascular niche, which through elaboration of paracrine trophogens stimulates organ regeneration, in a manner similar to endothelial-cell-derived angiocrine factors that support haematopoiesis. However, the precise mechanism by which tissue-specific subsets of endothelial cells promote organogenesis in adults is unknown. Here we demonstrate that liver sinusoidal endothelial cells (LSECs) constitute a unique population of phenotypically and functionally defined VEGFR3(+)CD34(-)VEGFR2(+)VE-cadherin(+)FactorVIII(+)CD45(-) endothelial cells, which through the release of angiocrine trophogens initiate and sustain liver regeneration induced by 70% partial hepatectomy. After partial hepatectomy, residual liver vasculature remains intact without experiencing hypoxia or structural damage, which allows study of physiological liver regeneration. Using this model, we show that inducible genetic ablation of vascular endothelial growth factor (VEGF)-A receptor-2 (VEGFR2) in the LSECs impairs the initial burst of hepatocyte proliferation (days 1-3 after partial hepatectomy) and subsequent reconstitution of the hepatovascular mass (days 4-8 after partial hepatectomy) by inhibiting upregulation of the endothelial-cell-specific transcription factor Id1. Accordingly, Id1-deficient mice also manifest defects throughout liver regeneration, owing to diminished expression of LSEC-derived angiocrine factors, including hepatocyte growth factor (HGF) and Wnt2. Notably, in in vitro co-cultures, VEGFR2-Id1 activation in LSECs stimulates hepatocyte proliferation. Indeed, intrasplenic transplantation of Id1(+/+) or Id1(-/-) LSECs transduced with Wnt2 and HGF (Id1(-/-)Wnt2(+)HGF(+) LSECs) re-establishes an inductive vascular niche in the liver sinusoids of the Id1(-/-) mice, initiating and restoring hepatovascular regeneration. Therefore, in the early phases of physiological liver regeneration, VEGFR2-Id1-mediated inductive angiogenesis in LSECs through release of angiocrine factors Wnt2 and HGF provokes hepatic proliferation. Subsequently, VEGFR2-Id1-dependent proliferative angiogenesis reconstitutes liver mass. Therapeutic co-transplantation of inductive VEGFR2(+)Id1(+)Wnt2(+)HGF(+) LSECs with hepatocytes provides an effective strategy to achieve durable liver regeneration.

Regulation of liver regeneration by growth factors and cytokines

The capability of the liver to fully regenerate after injury is a unique phenomenon essential for the maintenance of its important functions in the control of metabolism and xenobiotic detoxification. The regeneration process is histologically well described, but the genes that orchestrate liver regeneration have been only partially characterized. Of particular interest are cytokines and growth factors, which control different phases of liver regeneration. Historically, their potential functions in this process were addressed by analyzing their expression in the regenerating liver of rodents. Some of the predicted roles were confirmed using functional studies, including systemic delivery of recombinant growth factors, neutralizing antibodies or siRNAs prior to liver injury or during liver regeneration. In particular, the availability of genetically modified mice and their use in liver regeneration studies has unraveled novel and often unexpected functions of growth factors, cytokines and their downstream signalling targets in liver regeneration. This review summarizes the results obtained by functional studies that have addressed the roles and mechanisms of action of growth factors and cytokines in liver regeneration after acute injury to this organ.

Differential effects of VEGFR-1 and VEGFR-2 inhibition on tumor metastases based on host organ environment

Tumors induce new blood vessel growth primarily from host organ microvascular endothelial cells (EC), and microvasculature differs significantly between the lung and liver. Vascular endothelial growth factor (VEGF or VEGF-A) promotion of tumor angiogenesis is thought to be mediated primarily by VEGF receptor-2 (VEGFR-2). In this study, VEGFR-2 antibody (DC101) inhibited growth of RenCa renal cell carcinoma lung metastases by 26%, whereas VEGFR-1 antibody (MF-1) had no effect. However, VEGFR-2 neutralization had no effect on RenCa liver metastases, whereas VEGFR-1 neutralization decreased RenCa liver metastases by 31%. For CT26 colon carcinoma liver metastases, inhibition of both VEGFR-1 and VEGFR-2 was required to induce growth delay. VEGFR-1 or VEGFR-2 inhibition decreased tumor burden not by preventing the establishment of micrometastases but rather by preventing vascularization and growth of micrometastases by 55% and 43%, respectively. VEGF induced greater phosphorylation of VEGFR-2 in lung ECs and of VEGFR-1 in liver ECs. EC proliferation, migration, and capillary tube formation in vitro were suppressed more by VEGFR-2 inhibition for lung EC and more by VEGFR-1 inhibition for liver EC. Collectively, our results indicate that liver metastases are more reliant on VEGFR-1 than lung metastases to mediate angiogenesis due to differential activity of VEGFRs on liver EC versus lung EC. Thus, therapies inhibiting specific VEGFRs should consider the targeted sites of metastatic disease.

Advances in therapeutics for liver metastasis from colorectal cancer

The evolution of chemotherapeutic regimens that include targeted molecular agents has resulted in a breakthrough in the management of advanced colorectal liver metastasis (CLM), improving the progression-free survival after liver resection, and rendering initially unresectable liver tumors resectable, with reported resection rates ranging from 13% to 51%. In addition, the criteria used for selecting patients for hepatectomy have been expanding because of advances in surgical techniques and improvements in chemotherapy. However, the increasing use of chemotherapy has raised concern about potential hepatotoxicities such as steatosis, chemotherapy-associated steatohepatitis, and sinusoidal obstruction syndrome, and their deleterious effects on postoperative outcome. The present review focuses on the advantages and disadvantages of chemotherapy, strategies for the prevention and diagnosis of chemotherapy-associated liver injury, and the adoption of more aggressive surgical approaches, which have changed the traditional paradigm for CLM.

Inhibition of VEGF- and NO-dependent angiogenesis does not impair liver regeneration

Angiogenesis occurs through a convergence of diverse signaling mechanisms with prominent pathways that include autocrine effects of endothelial nitric oxide (NO) synthase (eNOS)-derived NO and vascular endothelial growth factor (VEGF). However, the redundant and distinct roles of NO and VEGF in angiogenesis remain incompletely defined. Here, we use the partial hepatectomy model in mice genetically deficient in eNOS to ascertain the influence of eNOS-derived NO on the angiogenesis that accompanies liver regeneration. While sinusoidal endothelial cell (SEC) eNOS promotes angiogenesis in vitro, surprisingly the absence of eNOS did not influence the angiogenesis that occurs after partial hepatectomy in vivo. While this observation could not be attributed to induction of alternate NOS isoforms, it was associated with induction of VEGF signaling as evidenced by enhanced levels of VEGF ligand in regenerating livers from mice genetically deficient in eNOS. However, surprisingly, mice that were genetically heterozygous for deficiency in the VEGF receptor, fetal liver kinase-1, also maintained unimpaired capacity for liver regeneration. In summary, inhibition of VEGF- and NO-dependent angiogenesis does not impair liver regeneration, indicating signaling redundancies that allow liver regeneration to continue in the absence of this canonical vascular pathway.

The vascular endothelial growth factor (VEGF) receptor-2 is a major regulator of VEGF-mediated salvage effect in murine acute hepatic failure

Although administration of the vascular endothelial growth factor (VEGF), a potent angiogenic factor, could improve the overall survival of destroyed sinusoidal endothelial cells (SEC) in chemically induced murine acute hepatic failure (AHF), the mechanistic roles of the VEGF receptors have not been elucidated yet. The respective roles of VEGF receptors; namely, Flt-1 (VEGFR-1: R1) and KDR/Flk-1 (VEGFR-2: R2), in the D-galactosamine (Gal-N) and lipopolysaccharide (LPS)-induced AHF were elucidated with specific neutralizing monoclonal antibody against R1 and R2 (R1-mAb and R2-mAb, respectively). The serum ALT elevation, with a peak at 24 h after Gal-N+LPS intoxication, was markedly augmented by means of the R1-mAb and R2-mAb. The aggregative effect of R2-mAb was more potent than that of R1-mAb, and the survival rate was 70% in the R2-mAb-treated group and 100% in the other groups. The results of SEC destruction were almost parallel to those of the ALT changes. Our in-vitro study showed that R1-mAb and R2-mAb significantly worsened the Gal-N+LPS-induced cytotoxicity and apoptosis of SEC mediated by caspase-3, which were almost of similar magnitude to those in the in-vivo study. In conclusion, these results indicated that R2 is a major regulator of the salvage effect of VEGF on the maintenance of SEC architecture and the anti-apoptotic effects against chemically-induced murine AHF.

Liver resection remains a safe procedure after neoadjuvant chemotherapy including bevacizumab: a case-controlled study

OBJECTIVE

This study was conducted to analyze if the combination of Bevacizumab with standard chemotherapy increases postoperative morbidity and mortality after resection of colorectal liver metastases as compared with resection after chemotherapy alone. Parameters contributing to an increased morbidity were evaluated.

SUMMARY BACKGROUND DATA

Most patients referred for colorectal liver metastases are treated with neoadjuvant chemotherapy before hepatic surgery. Targeted agents like the vascular endothelial growth factor-antagonist Bevacizumab are increasingly added to standard therapy to prolong survival; however, little is known about the consequences of this policy in the perioperative period.

METHODS

One hundred-two patients treated between 2005 and 2009, who received neoadjuvant chemotherapy combined with Bevacizumab (CHT + B) were identified. A cohort of 112 patients treated without chemotherapy alone before resection served as the control group (CHT). Complications were graded within an established staging system and the therapeutic consequences were laid down. Uni- and multivariate analysis of factors contributing to postoperative complications in the CHT + B group was performed using a logistic regression model.

RESULTS

Postoperative complications occurred in 45 (44%, CHT + B) and 38 (34%, CHT) patients, respectively (P = 0.216). The incidence of severe complications requiring surgical or radiologic intervention or leading to organ failure was 10.8% in the CHT + B group and 7.1% in the CHT group (P = 0.350). Increased age, low serum albumin, resection of more than 3 liver segments and synchronous bowel procedures requiring an anastomosis were associated with an increased morbidity rate in the multivariate regression analysis. No patient died in either group.

CONCLUSIONS

The addition of Bevacizumab to standard chemotherapy before resection of colorectal liver metastases does not seem to increase postoperative morbidity. Caution should be given to extended resections >3 liver segments and synchronous bowel anastomoses.

[Hepatotoxicity of metastatic colorectal cancer chemotherapy: systematic review]

AIM

Hepatic toxicity of chemotherapy for colorectal cancer and its complications after hepatic metastasis surgery are unclear. Studies reporting hepatic lesions after chemotherapy for colorectal cancer and published before July 2009 have been identified by searching the Medline database. Data concerning these hepatic lesions and outcome after surgery are resumed in this review.

RESULTS

Studies concerning the link between hepatic steatosis and chemotherapy have contradictory results but steatosis is clearly associated to an increase of postoperative morbidity. Steatohepatitis, especially due to irinotecan, is associated with increased postoperative mortality. Sinusoidal obstruction syndrome, a severe form of vascular hepatic lesion, associated to oxaliplatin, seems to be linked with an increase of postoperative morbidity, but not mortality. Bevacizumab would not increase, when used in combination with oxaliplatin, the rate of postoperative complications. Some studies suggest a decrease of vascular hepatic lesions when bevacizumab is administered with chemotherapy. The literature concerning hepatic toxicity of anti-EGF-R antibody is freak.

CONCLUSION

The fact that irinotecan may be linked to an increased risk of hepatic failure and postoperative death, which is not the case of oxaliplatine, must be taken in consideration in the choice of the preoperative chemotherapy before resection of hepatic metastasis of colorectal cancer.

[The safety of perioperative bevacizumab use]

AIM

Patients with colorectal cancer and liver metastases can benefit from preoperative chemotherapy and liver disease resection. Adjunction of bevacizumab (BV) to chemotherapy improves survival in these patients, but its impact on surgical complications remains to be fully determined.

METHODS

We reviewed all studies addressing mortality and morbidity following hepatectomy in patients preoperatively treated with a combination of BV and chemotherapy.

RESULTS

All available data are retrospective. For all patients, the interval between BV and surgery was at least one month. As compared to chemotherapy alone, they demonstrate no significant increase of the incidence of surgical complications, including wound healing delays, hepatocellular insufficiency, infections, and bleeding.

CONCLUSION

We still recommend managing an interval of at least 6 weeks from discontinuation of bevacizumab to hepatic resection, and at least 4 weeks from surgery to retreatment with bevacizumab. This recommendation is based on retrospective data and small numbers of patients, all indicating that BV use has no deleterious impact on postoperative morbidity and mortality.

RNA interference against hepatic epidermal growth factor receptor has suppressive effects on liver regeneration in rats

Liver regeneration after a two-thirds partial hepatectomy (PHx) is a complex process requiring interaction and cooperation of many growth factors and cytokines and cross talk between multiple pathways. Along with hepatocyte growth factor and its receptor MET (HGF-MET), the epidermal growth factor receptor (EGFR) signaling pathway is activated within 60 minutes after PHx. To investigate the role of EGFR in liver regeneration, we used two EGFR-specific short hairpin silencing RNAs to inhibit EGFR expression in regenerating normal rat liver. Suppression of EGFR mRNA and protein was evident in treated rats. There was also a demonstrable decrease but not complete elimination of bromo-deoxyuridine incorporation and mitoses at 24 hours after PHx. In addition, we observed up-regulation of MET and Src as well as activation of the ErbB-3-ErbB-2-PI3K-Akt pathway and down-regulation of STAT 3, cyclin D1, cyclin E1, p21, and C/EBP beta. The decrease in the ratio of C/EBP alpha to C/EBP beta known to occur after PHx was offset in shEGFR-treated rats. Despite suppression of hepatocyte proliferation lasting into day 3 after PHx, liver weight restoration occurred. Interestingly, hepatocytes in shEGFR-treated rats were considerably larger when compared with ScrRNA-treated controls. The data indicate that although the MET and EGFR pathways are similar, the contributions made by MET and EGFR are unique and are not compensated by each other or other cytokines.

Vascular endothelial growth factor targeted therapy in the perioperative setting: implications for patient care

Vascular endothelial growth factor (VEGF) targeted therapy, either alone or in combination with chemotherapy, has become the standard of care in several solid tumours, including colorectal cancer, renal-cell carcinoma, breast cancer, non-small-cell lung cancer, and glioblastoma. VEGF is crucial in the process of angiogenesis and wound healing and, thus, its inhibition has the potential to affect wound healing in patients undergoing surgery. In this review, we summarise the data available on the use of VEGF-targeted therapies, and their effect on perioperative wound complications. Surgery in patients receiving VEGF-targeted therapies seems to be safe when an appropriate interval of time is allowed between surgical procedures and treatment. Recommendations regarding this interval are provided in a disease and agent site-specific manner. We also discuss complications arising from the use of VEGF-directed therapies that might require surgical intervention and the considerations important in their management. At this juncture, safety data on the use of VEGF-targeted therapies in the perioperative period are sparse, and investigators are urged to continue to study this issue prospectively in current and future clinical trials to establish firm guidelines.

The anti-proliferative side effects of AEE788, a tyrosine kinase inhibitor blocking both EGF- and VEGF-receptor, are liver-size-dependent after partial hepatectomy in rats

BACKGROUND

Blocking of EGFR signaling by the tyrosine kinase inhibitor AEE788 was well tolerated and did not inhibit liver regeneration after standard 70% partial hepatectomy (PH) in a rat model, as demonstrated previously. However, serum levels of AEE788 at POW1 were 3-fold higher than in the non-resected control group. Therefore, we expanded theses studies to a model of extended 90%PH to investigate the role of liver size for the metabolism of AEE788 and its potential influence on side effects, liver regeneration and liver remodeling.

METHOD

Rats treated with 50 mg/kg AEE788 or solvent every other day orally were subjected to 90%PH. Animals were sacrificed at 1, 2, 7 and 28 days after PH. We measured plasma and liver levels of AEE788 and assessed anti-proliferative side effects, liver regeneration, and liver architecture.

RESULT

Liver regeneration and liver architecture were not impaired by AEE788 treatment after 90%PH. 90%PH caused a clinically relevant drug accumulation within 1 week of treatment (AEE788 serum and tissue levels: 90%PH*>70%PH*>normal control, *p < 0.05), suggesting a liver-size-dependent metabolism of the drug. Drug accumulation after 90%PH was associated with severe side effects (delayed body weight recovery, diarrhea, impaired hair growth) within 1 week of treatment.

CONCLUSION

Treatment with AEE788 could be a potential strategy for adjuvant treatment after oncological liver resection, as liver regeneration was not impaired. Our results suggest a liver-size-dependent metabolism of AEE788 leading to drug accumulation and subsequently to severe side effects. It calls for therapeutic drug monitoring in the early postoperative phase after extended resection.

Tumor necrosis factor-alpha and interleukin-1 antagonists alleviate inflammatory skin changes associated with epidermal growth factor receptor antibody therapy in mice

Cancer patients receiving epidermal growth factor receptor (EGFR) antibody therapy often experience an acneiform rash of uncertain etiology in skin regions rich in pilosebaceous units. Currently, this condition is treated symptomatically with very limited, often anecdotal success. Here, we show that a monoclonal antibody targeting murine EGFR, ME1, caused a neutrophil-rich hair follicle inflammation in mice, similar to that reported in patients. This effect was preceded by the appearance of lipid-filled hair follicle distensions adjacent to enlarged sebaceous glands. The cytokine tumor necrosis factor-alpha (TNFalpha), localized immunohistochemically to this affected region of the pilosebaceous unit, was specifically up-regulated by ME1 in skin but not in other tissues examined. Moreover, skin inflammation was reduced by cotreatment with the TNFalpha signaling inhibitor, etanercept, indicating the involvement of TNFalpha in this inflammatory process. Interleukin-1, a cytokine that frequently acts in concert with TNFalpha, is also involved in this process given the efficacy of the interleukin-1 antagonist Kineret. Our results provide a mechanistic framework to develop evidence-based trials for EGFR antibody-induced skin rash in patients with cancer.

Preoperative liver hypertrophy induced by portal flow occlusion before major hepatic resection for colorectal metastases can be impaired by bevacizumab

BACKGROUND

This prospective study evaluated the effect of bevacizumab on the hypertrophy of the future liver remnant (FLR) after portal vein occlusion (PVO) before major hepatectomy for colorectal liver metastases.

METHODS

Twenty-seven patients with colorectal liver metastases treated with preoperative FOLFOX/FOLFIRI chemotherapy regimen since 2002 were evaluated for the degree of hypertrophy of the FLR after right PVO. The results were compared with a similar group of 13 patients treated since 2006 with a chemotherapeutic regimen including bevacizumab and PVO. The FLR was measured by volumetric computed tomography 4 weeks before and after PVO.

RESULTS

Before PVO, the FLR volumes were similar in the 13 patients who received bevacizumab (bev+) (mean +/- standard deviation, 497 +/- 136 cm(3)) and the 27 patients who did not receive bevacizumab (bev-) (511 +/- 222 cm(3), P = NS). After PVO, the increase in the FLR volume was significantly lower in the bev+ group (561 +/- 171 cm(3)) compared with the bev- group (667 +/- 213 cm(3), P < .031). In the bev+ group, patients who had received six or more cycles and were > or =60 years old experienced far lower hypertrophy. A right hepatectomy was performed in 29 patients (72%) without mortality and no clinically important differences in morbidity.

CONCLUSIONS

Bevacizumab may impair hypertrophy of the FLR after PVO in preparation for major hepatectomy particularly, in patients aged > or =60 years and those who receive six or more cycles of bevacizumab, suggesting that major liver resection should be considered with caution in patients who have received bevacizumab.

Dose-dependent increases in circulating TGF-alpha and other EGFR ligands act as pharmacodynamic markers for optimal biological dosing of cetuximab and are tumor independent

PURPOSE

The objective of this study was to characterize treatment-induced circulating ligand changes during therapy with epidermal growth factor receptor (EGFR) inhibitors and evaluate their potential as surrogate indicators of the optimal biological dose.

EXPERIMENTAL DESIGN

Conditioned medium from human tumor cell lines, ascites fluid from tumor xenografts, and plasma samples from normal mice, as well as colorectal cancer patients, were assessed for ligand elevations using ELISA, following treatment with cetuximab (Erbitux), an anti-mouse EGFR neutralizing antibody, or a small-molecule EGFR tyrosine kinase inhibitor.

RESULTS

A rapid elevation in human transforming growth factor alpha (TGF-alpha) was observed in all cell lines after treatment with cetuximab, but not with small-molecule inhibitors. The elevation showed a dose-response effect and plateau that corresponded to the maximal decrease in A431 proliferation in vitro and HT29 tumor growth in vivo. The TGF-alpha increase was exacerbated by ongoing ligand production and cleavage from the plasma membrane but did not involve transcriptional up-regulation of TGF-alpha or the matrix metalloproteinase tumor necrosis factor-alpha-converting enzyme/ADAM17. Elevations in plasma TGF-alpha, amphiregulin, and epiregulin were also detected in normal mice treated with an anti-mouse EGFR monoclonal antibody, illustrating a host tissue-dependent component of this effect in vivo. Finally, circulating TGF-alpha increased in the plasma of six patients with EGFR-negative colorectal tumors during cetuximab treatment.

CONCLUSIONS

Treatment-induced increases in circulating ligands, particularly TGF-alpha, should be serially assessed in clinical trials of anti-EGFR therapeutic antibodies as potential biomarkers to aid in determination of the optimal biological dose.

Management of chemotherapy-associated hepatotoxicity in colorectal liver metastases

Effective systemic drugs are increasingly used to treat patients with colorectal liver metastases. Recent trials have shown that chemotherapy can reduce the size of metastases that are unresectable rendering them resectable, and decrease postoperative recurrence rates in patients with initially resectable tumours. The increasing use of chemotherapy for colorectal liver metastases has raised awareness of the potential hepatotoxicities induced by systemic drugs and the effects of these drugs on outcome after hepatic resection. In this Review, we outline the rationale for the use of perioperative chemotherapy for colorectal liver metastases, associations between specific agents and patterns of liver injury, and strategies to treat patients with suspected or known chemotherapy-associated hepatotoxicity.