Relative contribution of clinicopathological variables, genomic markers, transcriptomic subtyping and microenvironment features for outcome prediction in stage II/III colorectal cancer

BACKGROUND

It remains unknown to what extent consensus molecular subtype (CMS) groups and immune-stromal infiltration patterns improve our ability to predict outcomes over tumor-node-metastasis (TNM) staging and microsatellite instability (MSI) status in early-stage colorectal cancer (CRC).

PATIENTS AND METHODS

We carried out a comprehensive retrospective biomarker analysis of prognostic markers in adjuvant chemotherapy-untreated (N = 1656) and treated (N = 980), stage II (N = 1799) and III (N = 837) CRCs. We defined CMS scores and estimated CD8+ cytotoxic lymphocytes (CytoLym) and cancer-associated fibroblasts (CAF) infiltration scores from bulk tumor tissue transcriptomes (CMSclassifier and MCPcounter R packages); constructed a stratified multivariable Cox model for disease-free survival (DFS); and calculated the relative proportion of explained variation by each marker (clinicopathological [ClinPath], genomics [Gen: MSI, BRAF and KRAS mutations], CMS scores [CMS] and microenvironment cells [MicroCells: CytoLym+CAF]).

RESULTS

In multivariable models, only ClinPath and MicroCells remained significant prognostic factors, with both CytoLym and CAF infiltration scores improving survival prediction beyond other markers. The explained variation for DFS models of ClinPath, MicroCells, Gen markers and CMS4 scores was 77%, 14%, 5.3% and 3.7%, respectively, in stage II; and 55.9%, 35.1%, 4.1% and 0.9%, respectively, in stage III. Patients whose tumors were CytoLym high/CAF low had better DFS than other strata [HR=0.71 (0.6-0.9); P = 0.004]. Microsatellite stable tumors had the strongest signal for improved outcomes with CytoLym high scores (interaction P = 0.04) and the poor prognosis linked to high CAF scores was limited to stage III disease (interaction P = 0.04).

CONCLUSIONS

Our results confirm that tumor microenvironment infiltration patterns represent potent determinants of the risk for distant dissemination in early-stage CRC. Multivariable models suggest that the prognostic value of MSI and CMS groups is largely explained by CytoLym and CAF infiltration patterns.

Predicted vitamin D status and colon cancer recurrence and mortality in CALGB 89803 (Alliance)

Background

Observational studies suggest that higher levels of 25-hydroxyvitamin D3 (25(OH)D) are associated with a reduced risk of colorectal cancer and improved survival of colorectal cancer patients. However, the influence of vitamin D status on cancer recurrence and survival of patients with stage III colon cancer is unknown.

Patients and methods

We prospectively examined the influence of post-diagnosis predicted plasma 25(OH)D on outcome among 1016 patients with stage III colon cancer who were enrolled in a National Cancer Institute-sponsored adjuvant therapy trial (CALGB 89803). Predicted 25(OH)D scores were computed using validated regression models. We examined the influence of predicted 25(OH)D scores on cancer recurrence and mortality (disease-free survival; DFS) using Cox proportional hazards.

Results

Patients in the highest quintile of predicted 25(OH)D score had an adjusted hazard ratio (HR) for colon cancer recurrence or mortality (DFS) of 0.62 (95% confidence interval [CI], 0.44-0.86), compared with those in the lowest quintile (Ptrend = 0.005). Higher predicted 25(OH)D score was also associated with a significant improvement in recurrence-free survival and overall survival (Ptrend = 0.01 and 0.0004, respectively). The benefit associated with higher predicted 25(OH)D score appeared consistent across predictors of cancer outcome and strata of molecular tumor characteristics, including microsatellite instability and KRAS, BRAF, PIK3CA, and TP53 mutation status.

Conclusion

Higher predicted 25(OH)D levels after a diagnosis of stage III colon cancer may be associated with decreased recurrence and improved survival. Clinical trials assessing the benefit of vitamin D supplementation in the adjuvant setting are warranted.

ClinicalTrials.gov Identifier

NCT00003835.

Contrasting decadal-scale changes in elevation and vegetation in two Long Island Sound salt marshes

Northeastern US salt marshes face multiple co-stressors, including accelerating rates of relative sea level rise (RSLR), elevated nutrient inputs, and low sediment supplies. In order to evaluate how marsh surface elevations respond to such factors, we used surface elevation tables (SETs) and surface elevation pins to measure changes in marsh surface elevation in two eastern Long Island Sound salt marshes, Barn Island and Mamacoke Marsh. We compare marsh elevation change at these two systems with recent rates of RSLR and find evidence of differences between the two sites; Barn Island is maintaining its historic rate of elevation gain (2.3± 0.24 mm yr^-1 from 2003 to 2013) and is no longer keeping pace with RSLR, while Mamacoke shows evidence of a recent increase in rates (4.2 ± 0.52 mm yr^-1 from 1994 to 2014) to maintain its elevation relative to sea level. In addition to data on short-term elevation responses at these marshes, both sites have unusually long and detailed data on historic vegetation species composition extending back more than half a century. Over this study period, vegetation patterns track elevation change relative to sea levels, with the Barn Island plant community shifting towards those plants that are found at lower elevations and the Mamacoke vegetation patterns showing little change in plant composition. We hypothesize that the apparent contrasting trend in marsh elevation at the sites is due to differences in sediment availability, salinity, and elevation capital. Together these two systems provide critical insight into the relationships between marsh elevation, high marsh plant community, and changing hydroperiods. Our results highlight that not all marshes in southern New England may be responding to accelerated rates of RSLR in the same manner.

Incomplete inhibition of phosphorylation of 4E-BP1 as a mechanism of primary resistance to ATP-competitive mTOR inhibitors

The mammalian target of rapamycin (mTOR) regulates cell growth by integrating nutrient and growth factor signaling and is strongly implicated in cancer. But mTOR is not an oncogene, and which tumors will be resistant or sensitive to new ATP-competitive mTOR inhibitors now in clinical trials remains unknown. We screened a panel of over 600 human cancer cell lines to identify markers of resistance and sensitivity to the mTOR inhibitor PP242. RAS and PIK3CA mutations were the most significant genetic markers for resistance and sensitivity to PP242, respectively; colon origin was the most significant marker for resistance based on tissue type. Among colon cancer cell lines, those with KRAS mutations were most resistant to PP242, while those without KRAS mutations most sensitive. Surprisingly, cell lines with co-mutation of PIK3CA and KRAS had intermediate sensitivity. Immunoblot analysis of the signaling targets downstream of mTOR revealed that the degree of cellular growth inhibition induced by PP242 was correlated with inhibition of phosphorylation of the translational repressor 4E-BP1, but not ribosomal protein S6. In a tumor growth inhibition trial of PP242 in patient-derived colon cancer xenografts, resistance to PP242 induced inhibition of 4E-BP1 phosphorylation and xenograft growth was again observed in KRAS mutant tumors without PIK3CA co-mutation, compared to KRAS WT controls. We show that, in the absence of PIK3CA co-mutation, KRAS mutations are associated with resistance to PP242 and that this is specifically linked to changes in the level of phosphorylation of 4E-BP1.

Presence of 18q loss of heterozygosity (LOH) and disease-free and overall survival in stage II colon cancer: CALGB Protocol 9581

4012

Background: LOH at 18q is associated with poorer overall survival in patients with colon cancer; however available studies are retrospective and vary in analysis methods. We recently completed an 18qLOH assay method validation study, and after standardizing technique, this prospective study investigated the role of 18qLOH among patients with low-risk stage II colon cancer. Methods: In Cancer and Leukemia Group B (CALGB) protocol 9581, we randomized 1738 stage II patients to post-operative treatment with a 500 mg loading dose of monoclonal antibody 17–1A followed by four infusions of 100 mg every 28 days or observation. The primary endpoint was overall survival (OS); disease free survival (DFS) was a secondary endpoint. Status of 18qLOH was assessed in patients with available tissue and interpretable PCR results. Patients were excluded if their tumors were uninformative for 18qLOH or if their tumors displayed microsatellite instability. Results: We report 18qLOH data on 156 patients. Patient characteristics including treatment, age, gender, performance status, site and grade of tumor, were similar between all patients enrolled and the subset of patients with tumor samples analyzed. The DFS and OS for treated and observed patients were no different (5-yr DFS: 0.81 and 0.80, p= 0.96; 5-yr OS: 0.88 and 0.86, p=0.44 at a median of 6.8 yrs of follow-up) and the data were pooled across the study's arms. Of the tumors examined, 101 (65%) were positive for 18qLOH. A significantly lower proportion of patients with 18qLOH-positive tumors had proximal tumors (46.5% vs 65.5%; p=0.02). Significantly decreased DFS and OS were observed in patients with 18qLOH-positive tumors. Five-year DFS among patients with 18qLOH-positive tumors was 0.78 vs 0.93 among patients with 18qLOH-negative tumors [HR 0.39; 95% CI (0.16, 0.94); logrank p=0.03 based on 33 events]. Five-year OS among patients with 18qLOH-positive tumors was 0.85 vs 0.98 among patients with 18qLOH-negative tumors [HR 0.25; 95% CI (0.07, 0.83); logrank p=0.01 based on 24 events]. Conclusions LOH at 18q was prognostic for DFS and OS among patients with available tissue for analysis after resection of low-risk stage II colon cancer who were not treated with chemotherapy in the adjuvant setting.

[Table: see text]

Microsatellite instability predicts improved response to adjuvant therapy with irinotecan, 5-fluorouracil and leucovorin in stage III colon cancer

10003

Background: Colon cancers exhibiting a high level of microsatellite instability (MSI-H) show distinct clinicopathological features, including both better prognosis and reduced response to 5-fluorouracil (5-FU)-based chemotherapy. We investigated the impact of adjuvant chemotherapy containing irinotecan in patients with MSI-H colon cancers. Methods: CALGB protocol 89803 randomized 1264 patients with resected stage III colon cancer to receive post-operative 5-FU and leucovorin (LV) with or without irinotecan. Paraffin blocks containing primary tumor and normal tissue were collected. Microsatellite instablility was assessed using a panel of mono- and di-nucleotide markers. Disease free survival (DFS) was measured from trial entry until documented disease progression or death from any cause. A statistical significance level of 0.2 was used in screening to generate hypotheses regarding MSI status and outcome. Median follow-up at analysis was 3.8 years. Overall C89803 showed no advantage for addition of irinotecan to 5-FU/LV. Results: Patients with and without tumor samples analyzed did not differ by treatment, age, gender, primary site, T-stage, differentiation, # positive nodes, or mucinous type. Of 482 tumors analyzed, 75 (16%) demonstrated MSI-H. MSI-H cancers were more likely to be located in the proximal colon (p<0.0001), of high histologic grade (p<0.0001) and mucinous histology (p<0.0001), and also had increased numbers of tumor-containing lymph nodes (mean # positive nodes/case = 3.5 for MSI Low/Stable vs. 4.7 for MSI-H; p = 0.04). At the time of analysis 143 of 482 patients (36%) analyzed experienced tumor recurrence and/or death due to any cause. For patients with MSI-H tumors, DFS was better in those treated with irinotecan in addition to 5-FU/LV (logrank p=0.18). Among patients with MSI Low/Stable tumors there was no difference in DFS between those treated with and without irinotecan (logrank p =0.39). Conclusions: Early results from CALGB protocol 89803 indicate that addition of postoperative irinotecan to 5-FU/LV may improve DFS in patients with stage III colon cancers that exhibit MSI-H. Longer follow-up is required to confirm this finding.

[Table: see text]

Expression of the coxsackievirus- and adenovirus receptor in gastrointestinal cancer correlates with tumor differentiation

Modified adenoviruses represent a new approach to treatment of gastrointestinal cancer. However, their uptake by cells in many cases requires the major receptor for adenoviruses, the coxsackievirus and adenovirus receptor (CAR). Thus, lack of CAR expression is a potential cause of intrinsic resistance of tumor cells to this type of treatment. To evaluate this, we studied the localization of CAR protein in normal and malignant gastrointestinal tissues. In normal tissues, CAR was concentrated at sites of cell-cell interaction, in particular at the apico-lateral cellular surface. Expression was particularly strong around bile and pancreatic ducts, which is in agreement with CAR's physiological function as a tight-junction protein. In GI malignancies (esophageal, pancreatic, colorectal and liver cancer), expression of the receptor varied substantially. Loss of CAR expression at cell-cell junction was evident in many samples. A significant correlation between CAR expression and histological grade was found, with moderately to poorly differentiated tumors most frequently demonstrating loss or reduction of CAR expression. These data indicate that CAR expression is frequently altered in gastrointestinal malignancy, potentially reducing the efficacy of adenovirus-based therapies.

Vascular endothelial cell growth factor activates CRE-binding protein by signaling through the KDR receptor tyrosine kinase

Vascular endothelial cell growth factor (VEGF) plays a crucial role in the development of the cardiovascular system and in promoting angiogenesis associated with physiological and pathological processes. Although a great deal is known of the cytoplasmic signaling pathways activated by VEGF, much less is known of the mechanisms through which VEGF communicates with the nucleus and alters the activity of transcription factors. Binding of VEGF to the KDR/Flk1 receptor tyrosine kinase induces phosphorylation of the CRE-binding protein (CREB) transcription factor on serine 133 and increases CREB DNA binding and transactivation. p38 MAPK/MSK-1 and protein kinase C/p90RSK pathways mediate CREB phosphorylation. Confocal microscopy shows that VEGF-induced phosphorylation of nuclear CREB is blocked by pharmacological inhibition of protein kinase C and p38 mitogen-activated protein kinase signaling. Thus, KDR/Flk1 uses multiple pathways to transmit signals into the nucleus where CREB becomes activated. These results suggest that CREB may play a role in alterations of gene expression important to angiogenesis.

Quantitative mRNA expression analysis from formalin-fixed, paraffin-embedded tissues using 5' nuclease quantitative reverse transcription-polymerase chain reaction

Analysis of gene expression and correlation with clinical parameters has the potential to become an important factor in therapeutic decision making. The ability to analyze gene expression in archived tissues, for which clinical followup is already available, will greatly facilitate research in this area. A major obstacle to this approach, however, has been the uncertainty about whether gene expression analyses from routinely archived tissues accurately reflect expression before fixation. In the present study we have optimized the RNA isolation and reverse transcription steps for quantitative reverse transcription-polymerase chain reaction (RT-PCR) on archival material. Using tissue taken directly from the operating room, mRNAs with half-lives from 10 minutes to >8 hours were isolated and reverse transcribed. Subsequent real-time quantitative PCR methodology (TaqMan) on these cDNAs gives a measurement of gene expression in the fixed tissues comparable to that in the fresh tissue. In addition, we simulated routine pathology handling and demonstrate that this method of mRNA quantitation is insensitive to pre-fixation times (time from excision to fixation) of up to 12 hours. Therefore, it should be feasible to analyze gene expression in archived tissues where tissue collection procedures are largely unknown.

Therapeutic approaches to metastasis confined to the liver

Liver metastases nearly always represent disseminated cancer, and systemic therapies are usually indicated. However, in a minority of patients--some with colorectal cancer, others with selected tumors--management of the hepatic disease may be clinically important and even curative. This review identifies unique patient subgroups and novel treatment approaches that may be indicated in patients with liver metastases.

Current management of colorectal liver metastases

Colorectal cancer metastatic to the liver represents an uncommon situation in surgical oncology in which metastasectomy can effect longevity and may lead to cure. Liver resection can be done safely and has drastically improved 5-year survival rates to upwards of 35%, but only a minority of patients is eligible. Advances in imaging techniques facilitate detection of metastases and improve patient selection. For unresectable patients, and as an adjunct to resection, local disease control may be achieved with cryosurgery, radiofrequency ablation, or regional chemotherapy delivered by way of infusion through the hepatic artery. Areas of ongoing investigation include regional gene therapy and interference with tumor growth by inhibition of angiogenesis.

Homeostatic modulation of cell surface KDR and Flt1 expression and expression of the vascular endothelial cell growth factor (VEGF) receptor mRNAs by VEGF

Vascular endothelial cell growth factor (VEGF) is a potent angiogenic factor expressed during embryonic development, during wound healing, and in pathologies dependent on neovascularization, including cancer. Regulation of the receptor tyrosine kinases, KDR and Flt-1, to which VEGF binds on endothelial cells is incompletely understood. Chronic incubation with tumor-conditioned medium or VEGF diminished (125)I-VEGF binding to human umbilical vein endothelial cells, incorporation of (125)I-VEGF into covalent complexes with KDR and Flt1, and immunoreactive KDR in cell lysates. Receptor down-regulation desensitized VEGF activation of mitogen-activated protein kinase (extracellular signal-regulated kinases 1 and 2) and p38 mitogen-activated protein kinase. Preincubation with VEGF or tumor-conditioned medium down-regulated cell surface receptor expression but up-regulated KDR and Flt-1 mRNAs, an effect abrogated by a neutralizing VEGF antibody. Removal of VEGF from the medium led to recovery of (125)I-VEGF binding and resensitization of human umbilical vein endothelial cells. Recovery of receptor expression was inhibited by cycloheximide, indicating that augmented VEGF receptor mRNAs, and not receptor recycling from a cytoplasmic pool, restored responsiveness. As the VEGF receptors promote endothelial cell survival, proliferation, and other events necessary for angiogenesis, the noncoordinate regulation of VEGF receptor proteins and mRNAs suggests that human umbilical vein endothelial cells are protected against inappropriate or prolonged loss of VEGF receptors by a homeostatic mechanism important to endothelial cell function.

Tumor necrosis factor employs a protein-tyrosine phosphatase to inhibit activation of KDR and vascular endothelial cell growth factor-induced endothelial cell proliferation

Vascular endothelial cell growth factor (VEGF) binds to and promotes the activation of one of its receptors, KDR. Once activated, KDR induces the tyrosine phosphorylation of cytoplasmic signaling proteins that are important to endothelial cell proliferation. In human umbilical vein endothelial cells (HUVECs), tumor necrosis factor (TNF) inhibits the phosphorylation and activation of KDR. The ability of TNF to diminish VEGF-stimulated KDR activity was impaired by sodium orthovanadate, suggesting that the inhibitory activity of TNF was mediated by a protein-tyrosine phosphatase. KDR-initiated responses specifically associated with endothelial cell proliferation, mitogen-activated protein kinase activation and DNA synthesis, were also inhibited by TNF, and this was reversed by sodium orthovanadate. Stimulation of HUVECs with TNF induced association of the SHP-1 protein-tyrosine phosphatase with KDR, identifying this phosphatase as a candidate negative regulator of VEGF signal transduction. Heterologous receptor inactivation mediated by a protein-tyrosine phosphatase provides insight into how TNF may inhibit endothelial cell proliferative responses and modulate angiogenesis in pathological settings.

VRAP is an adaptor protein that binds KDR, a receptor for vascular endothelial cell growth factor

A protein that binds the intracellular domain of KDR (KDR-IC), a receptor for vascular endothelial cell growth factor (VEGF), was identified by two-hybrid screening. Two-hybrid mapping showed that the VEGF receptor-associated protein (VRAP) interacted with tyrosine 951 in the kinase insert domain of KDR. Northern blot analysis identified multiple VRAP transcripts in peripheral leukocytes, spleen, thymus, heart, lung, and human umbilical vein endothelial cells (HUVEC). The predominant VRAP mRNA encodes a 389-amino acid protein that contains an SH2 domain and a C-terminal proline-rich motif. In HUVEC, VEGF promotes association of VRAP with KDR. Phospholipase C gamma and phosphatidylinositol 3-kinase, effector proteins that are downstream of KDR and important to VEGF-induced endothelial cell survival and proliferative responses, associate constitutively with VRAP. These observations identify VRAP as an adaptor that recruits cytoplasmic signaling proteins to KDR, which plays an important role in normal and pathological angiogenesis.

Angiogenesis, proliferation, and apoptosis in anal high-grade squamous intraepithelial lesions

PURPOSE

Management of anal high-grade squamous intraepithelial lesions is controversial. Anal and cervical high-grade squamous intraepithelial lesions are similar in that they occur in transitional squamous epithelium, are associated with human papilloma virus infection, and have increased incidence in the immunocompromised population. Ablation of cervical high-grade squamous intraepithelial lesions is preferred, but similar ablation or excision of anal high-grade squamous intraepithelial lesions may compromise bowel control; thus, there is a need to define the malignant potential of anal high-grade squamous intraepithelial lesions.

METHODS

We analyzed 50 paraffin sections of normal anoderm, anal low-grade squamous intraepithelial lesions, high-grade squamous intraepithelial lesions, and anal squamous-cell carcinoma. Microvessels were detected immunohistochemically with von Willebrand factor and counted manually along the epithelial-stromal junction. Proliferation and apoptosis were determined in the epithelial cells with MIB-1 antibody immunostaining and the terminal deoxynucleotidyl transferase-mediated digoxigenin-11-dUTP nick end labeling, respectively.

RESULTS

Microvascular density was significantly greater in anal high-grade squamous intraepithelial lesions (mean, 0.50 vessels/cm) vs. normal anoderm (mean, 0.21 vessels/cm; P = 0.0017, Mann-Whitney U test). The proliferative percentages were greater in low-grade squamous intraepithelial lesions, high-grade squamous intraepithelial lesions, and squamous-cell carcinoma (mean, 20.4, 21.8, and 23.6 percent) vs. normal anoderm (mean, 14.4 percent), although not significantly (P = 0.06, Kruskal-Wallis statistic). Although the mean proliferative proportions were similar in low-grade squamous intraepithelial lesions and high-grade squamous intraepithelial lesions, the apoptotic proportion was lower for high-grade squamous intraepithelial lesions than low-grade squamous intraepithelial lesions (10.13 vs. 19.96 percent, respectively; P = NS, Mann-Whitney U test).

CONCLUSIONS

Angiogenesis, increased proliferation, and decreased apoptosis occur in anal high-grade squamous intraepithelial lesions as they do in the cervix before the development of malignancy. These biologic markers support the importance of anal high-grade squamous intraepithelial lesions as a potential premalignant lesion warranting surgical intervention.

Utilization of distinct signaling pathways by receptors for vascular endothelial cell growth factor and other mitogens in the induction of endothelial cell proliferation

This study was initiated to identify signaling proteins used by the receptors for vascular endothelial cell growth factor KDR/Flk1, and Flt1. Two-hybrid cloning and immunoprecipitation from human umbilical vein endothelial cells (HUVEC) showed that KDR binds to and promotes the tyrosine phosphorylation of phospholipase Cgamma (PLCgamma). Neither placental growth factor, which activates Flt1, epidermal growth factor (EGF), or fibroblast growth factor (FGF) induced tyrosine phosphorylation of PLCgamma, indicating that KDR is uniquely important to PLCgamma activation in HUVEC. By signaling through KDR, VEGF promoted the tyrosine phosphorylation of focal adhesion kinase, induced activation of Akt, protein kinase Cepsilon (PKCepsilon), mitogen-activated protein kinase (MAPK), and promoted thymidine incorporation into DNA. VEGF activates PLCgamma, PKCepsilon, and phosphatidylinositol 3-kinase independently of one another. MEK, PLCgamma, and to a lesser extent PKC, are in the pathway through which KDR activates MAPK. PLCgamma or PKC inhibitors did not affect FGF- or EGF-mediated MAPK activation. MAPK/ERK kinase inhibition diminished VEGF-, FGF-, and EGF-promoted thymidine incorporation into DNA. However, blockade of PKC diminished thymidine incorporation into DNA induced by VEGF but not FGF or EGF. Signaling through KDR/Flk1 activates signaling pathways not utilized by other mitogens to induce proliferation of HUVEC.

Characterization of the CoA ligases of human liver mitochondria catalyzing the activation of short- and medium-chain fatty acids and xenobiotic carboxylic acids

Two distinct forms of xenobiotic/medium-chain fatty acid:CoA ligase (XM-ligase) were isolated from human liver mitochondria. They were referred to as HXM-A and HXM-B based on their order of elution from a DEAE-cellulose column. Activity of the two ligases was determined toward 15 different carboxylic acids. HXM-A represented 60-80% of the benzoate activity in the lysate, and kinetic analysis revealed that benzoate was the best substrate (highest V(max)/K(m)). The enzyme also had medium-chain fatty acid:CoA ligase activity. HXM-B had the majority of the hexanoate activity and hexanoate was its best substrate. It was, however, also active toward many xenobiotic carboxylic acids. Comparison of these two human XM-ligases with the previously characterized bovine XM-ligases indicated that they were kinetically distinct. When assayed with benzoic acid as substrate, both HXM-A and HXM-B had an absolute dependence on either Mg(2+) or Mn(2+) for activity. Further, addition of monovalent cation (K(+), Rb(+), or NH(4)(+)) stimulated HXM-A activity by >30-fold and HXM-B activity by 4-fold. For both forms, activity toward straight-chain fatty acids was stimulated less by K(+) than was activity toward benzoate or phenylacetate. A 60 kDa short-chain fatty acid:CoA ligase was also isolated. It had activity toward propionate and butyrate, but not acetate, hexanoate or benzoate. The K(m)(app) values were high but similar for propionate and butyrate (285 microM and 250 microM, respectively) but the V(max)(app) was nearly 6-fold greater with propionate as substrate. While the K(m) values are somewhat high, the enzyme is still more efficient with these substrates than either of the XM-ligases.

Chromosome arm 20q gains and other genomic alterations in colorectal cancer metastatic to liver, as analyzed by comparative genomic hybridization and fluorescence in situ hybridization

Comprehensive information about the molecular cytogenetic changes in metastases of colorectal cancer is not yet available. To define such changes in metastases, we measured relative DNA sequence copy numbers by comparative genomic hybridization (CGH). Samples from 27 liver metastases and 6 synchronous primary tumors were analyzed. An average of 9.9 aberrations per tumor was found in the metastases. Gains of chromosome arms 20q (85%), 13q (48%), 7p (44%), and 8q (44%) and losses of chromosome arms 18q (89%), 8p (59%), 1p (56%), and 18p (48%) were detected most frequently. Chromosomes 14 and 15 were lost in 26% and 30% of the metastases, respectively. No consistent differences were observed between primary tumors and synchronous metastases. Fluorescence in situ hybridization (FISH) was used for further characterization of gains of chromosome arm 20q. Touch preparations of 13 tumors that had demonstrated 20q gain with CGH were examined with FISH by use of a set of probes mapping to different parts of 20q. A probe for 20p was used as a reference. FISH showed relative gain of at least one 20q locus in 12 of the tumors. High-level gains were detected in 38% of the tumors, preferentially for probes mapping to band 20q13. Our CGH data indicate that colorectal metastases show chromosomal changes similar to those that have been reported for primary tumors. Chromosomal losses were seen at higher frequency, particularly for chromosomes 14 and 15. By FISH, we identified subregions on chromosome arm 20q that are frequently involved in DNA amplifications in colorectal cancer and that may harbor candidate proto-oncogenes.

The relationship between hospital volume and outcomes of hepatic resection for hepatocellular carcinoma

BACKGROUND

Volume-outcome relations have been established for several complex therapies. However, few studies have examined volume-outcome relations for high-risk procedures in general surgery, such as hepatectomy for hepatocellular carcinoma (HCC).

OBJECTIVE

To evaluate the relation between hospital volume and outcome for patients undergoing hepatectomy for HCC.

DESIGN

Retrospective cohort study.

SETTING

All acute-care hospitals in California.

PATIENTS

Hospital discharge data were analyzed for each patient in California who underwent major hepatic resection for HCC from January 1, 1990, through December 31, 1994. Hospitals were grouped according to number of hepatectomies performed at each center during the 5-year study.

MAIN OUTCOME MEASURES

Outcome measures included operative mortality and length of hospital stay. Regression analyses were used to adjust for differences in patient mix.

RESULTS

Five hundred seven patients underwent hepatectomy for HCC during the study. Hepatic resections were performed in 138 hospitals, with an overall in-hospital mortality rate of 14.8%. Three quarters of patients were treated at hospitals that average 3 or fewer hepatic resections for HCC per year. These low-volume providers represent 97.1% of all hospitals treating patients with HCC statewide. Significant reductions in risk-adjusted operative mortality rates (22.7%-9.4%; P = .002, multiple logistic regression) and risk-adjusted length of stay (14.3-11.3 days; P = .03, multiple linear regression) were observed as hospital volume increased.

CONCLUSIONS

Low operative mortality and length of stay were associated with high-volume centers. These data support regionalization of high-risk procedures in general surgery, such as hepatectomy for HCC.

Coordinated induction of VEGF receptors in mesenchymal cell types during rat hepatic wound healing

Homology PCR has been used to identify receptor tyrosine kinases (RTKs) expressed during activation of rat hepatic stellate cells, the key fibrogenic mesenchymal element in the liver. Partial cDNAs encoding several RTKs were cloned from stellate cells activated in vivo, including those of Flt-1, Flk-1, c-met, PDGFR, and Tyro10/DDR2. RNAse protection from cells activated in vivo demonstrated biphasic induction of flt-1 and flk-1 mRNAs, receptors for vascular endothelial growth factor (VEGF). Culture-activation of stellate cells was associated with increased [125I]VEGF binding and Flt-1 and Flk-1 receptor protein. Induction of VEGF binding sites correlated with an 2.5-fold increase in DNA synthesis in response to VEGF, but only if cells were activated by growth on collagen 1, whereas cells maintained in a quiescent state on a basement membrane-like substratum (EHS matrix) were nonproliferative. In both stellate and endothelial cells VEGF-induced mitogenesis was augmented by co-incubation with basic fibroblast growth factor (bFGF), a cytokine with known synergy with VEGF. These findings suggest that the cellular targets of VEGF in liver may not be confined to sinusoidal endothelial cells, and that VEGF responses reflect combined effects on both hepatic stellate cells and sinusoidal endothelium.

Bird Use of Restoration and Reference Marshes Within the Barn Island Wildlife Management Area, Stonington, Connecticut, USA

/ Tidal marshes have been actively restored in Connecticut for nearly 20 years, but evaluations of these projects are typically based solely on observations of vegetation change. A formerly impounded valley marsh at the Barn Island Wildlife Management Area is a notable exception; previous research at this site has also included assessments of primary productivity, macroinvertebrates, and use by fishes. To determine the effects of marsh restoration on higher trophic levels, we monitored bird use at five sites within the Barn Island complex, including both restoration and reference marshes. Use by summer bird populations within fixed plots was monitored over two years at all sites. Our principal focus was Impoundment One, a previously impounded valley marsh reopened to full tidal exchange in 1982. This restoration site supported a greater abundance of wetland birds than our other sites, indicating that it is at least equivalent to reference marshes within the same system for this ecological function. Moreover, the species richness of birds and their frequency of occurrence at Impoundment One was greater than at 11 other estuarine marshes in southeastern Connecticut surveyed in a related investigation. A second marsh, under restoration for approximately ten years, appears to be developing in a similar fashion. These results complement previous studies on vegetation, macroinvertebrates, and fish use in this system to show that, over time, the reintroduction of tidal flooding can effectively restore important ecological functions to previously impounded tidal marshes.KEY WORDS: Estuarine; Tidal marsh; Wetland birds; Restoration

Mutations of the PATCHED gene in several types of sporadic extracutaneous tumors

Patients with basal cell nevus syndrome have a high incidence of multiple basal cell carcinomas, medulloblastomas, and meningiomas. Because somatic PATCHED (PTCH) mutations have been found in sporadic basal cell carcinomas, we have screened for PTCH mutations in several types of sporadic extracutaneous tumors. We found that 2 of 14 sporadic medulloblastomas bear somatic nonsense mutations in one copy of the gene and also deletion of the other copy. In addition, we identified missense mutations in PTCH in two of seven breast carcinomas, one of nine meningiomas, and one colon cancer cell line. No PTCH gene mutations were detected in 10 primary colon carcinomas and eighteen bladder carcinomas.

Molecular cytogenetic analysis of cytokeratin 20-labeled cells in primary tumors and bone marrow aspirates from colorectal carcinoma patients

BACKGROUND

Low frequency epithelial cells in bone marrow from colorectal carcinoma patients are associated with an increased risk of recurrence and decreased survival. Current immunohistochemical approaches to detect epithelial cells in bone marrow aspirates rely on antibodies against cytokeratin 18 (CK18). The predictive value of CK18-based detection strategies is limited by false-positives that occur in approximately 30% of cases. Cross-reactivity of anti-CK18 antibodies with nontumor cells may contribute to the false-positive rate. Cytokeratin 20 (CK20) shows more restricted expression than CK18 and labels cells in colorectal tumors.

METHODS

Immunofluorescence assays were used to quantify CK20-labeled cells in bone marrow aspirates and tumors from 18 Dukes stage C and D colorectal carcinoma patients to determine whether CK20 is useful in detecting micrometastases. Fluorescent in situ hybridization was used to determine whether CK-labeled subpopulations carried genomic aberrations associated with colorectal carcinoma.

RESULTS

CK20-labeled cells occurred at frequencies approximately 5 x 10(-5) in control bone marrow aspirates from patients without colorectal carcinomas. Approximately 10(-4) CK20-labeled cells were present in 4 of 11 bone marrow aspirates (45%) from patients with Dukes stage D colon carcinoma. The mean frequency (5 x 10(-5) of CK20-labeled cells in Dukes stage C and D rectal carcinoma patients was statistically similar to control values. CONCLUSIONS. A subset of CK20-labeled cells in primary tumors and hepatic metastases are aneusomic. CK20-labeled cells in bone marrow aspirates are cytogenetically normal. These data demonstrate that CK20 cells in solid tumors may be cytogenetically aberrant, but suggest caution in the use of CK20 to detect micrometastases in bone marrow aspirates.

Induction of vascular endothelial growth factor by insulin-like growth factor 1 in colorectal carcinoma

Vascular endothelial growth factor (VEGF) is an angiogenic hormone that is produced by and supports the growth of many types of malignancies. The present study shows that insulin-like growth factor 1 (IGF-I), a mitogen that promotes the propagation of cancers through autocrine and paracrine mechanisms, increases the expression of mRNA for VEGF and production of VEGF protein by COLO 205 colon carcinoma cells. IGF-I also induces expression of VEGF mRNA in SW620, LSLiM6, and HCT15 colon carcinoma cells showing that this is a common response to IGF-I. Whereas IGF-I induced VEGF mRNA in each cell line examined (2.3-12-fold), it induced proliferation only in COLO 205 and LSLiM6 cells. Thus, the proliferative response induced by IGF-I and its ability to induce VEGF occur through distinguishable mechanisms. IGF-I increases the cellular content of VEGF mRNA by increasing the rate of transcription (5-fold after 4 h) and also by increasing the half-life of VEGF mRNA (0.6 +/- 0.07 h in control cells to 2.0 +/- 0.37 h in IGF-I-treated cells). Monoclonal antibody (alphaIR3) directed against the type 1 IGF receptor significantly attenuated the ability of IGF-I to promote expression of VEGF mRNA. Interestingly, by itself alphaIR3 acted as a weak agonist and induced a modest increase in the cellular content of VEGF mRNA. alphaIR3 also promoted tyrosine phosphorylation of the beta subunit of the IGF-I receptor, and the magnitude of this response was comparable with that induced by IGF-I. These observations point to a nonlinear relationship between activation of the IGF-I receptor and induction of VEGF mRNA. Thus, in addition to its direct, growth stimulatory effect on transformed cells, IGF-I induces the expression of VEGF which can promote the progression of cancer by regulating the development of new blood vessels.

Intra-abdominal desmoplastic small round-cell tumor: expansion of the pathologic profile

This report describes an intra-abdominal desmoplastic small round-cell tumor in a 29-year-old man that significantly differed from the classically described appearances of this unique tumor. It showed extensive papillary areas, no necrosis, and very little desmoplasia. The latter was limited, paucicellular, and present in areas separate from the papillary structures. Also, areas of back-to-back, single-cell infiltration, which mimicked lobular breast carcinoma, were present. These epithelial features suggested the diagnosis of adenocarcinoma or peculiar mesothelioma. But, the immunohistochemical features (tumor cells positive for keratin, desmin, and vimentin) were more consistent with an intra-abdominal desmoplastic small round-cell tumor. The diagnosis became clear after application of reverse transcriptase-polymerase chain reaction techniques to formalin-fixed, paraffin-embedded tissue, which showed the presence of a 100-base pair product containing the fusion junction of Ewing's sarcoma-1 exon 7 to Wilms' tumor-1 exon 8. This feature is considered unique to intra-abdominal desmoplastic small round-cell tumors. This case illustrates the less common histologic findings that can be found in intra-abdominal desmoplastic small round-cell tumor. This deviation from the classic histologic findings may be an expression of an uncommon morphologic variant and/or partially produced by the effects of prior chemotherapy. In either event, only by illustrating the various histologic appearances of intra-abdominal desmoplastic small round-cell tumor are the chances increased for the accurate diagnosis of this aggressive neoplasm with a poor prognosis.

Regional chemotherapy approaches for primary and metastatic liver tumors

There are pharmacologic principles that make regional chemotherapy to the liver a logical treatment strategy. Patients with colorectal liver metastases and hepatocellular carcinoma would appear to be the best candidates for such an approach. Although there are many objective responses to such treatment, survival benefit has not been demonstrated, but new regimens and refined techniques appear to be improving results. Ultimately, regional delivery may be best suited for innovative treatments such as biologicals and gene therapies.

Regulation by vascular endothelial growth factor of human colon cancer tumorigenesis in a mouse model of experimental liver metastasis

To investigate the relationship between angiogenesis and hepatic tumorigenesis, we examined the expression of vascular endothelial growth factor (VEGF) in 8 human colon carcinoma cell lines and in 30 human colorectal cancer liver metastases. Abundant message for VEGF was found in all tumors, localized to the malignant cells within each neoplasm. Two receptors for VEGF, KDR and flt1, were also demonstrated in most of the tumors examined. KDR and flt1 mRNA were limited to tumor endothelial cells and were more strongly expressed in the hepatic metastases than in the sinusoidal endothelium of the surrounding liver parenchyma. VEGF monoclonal antibody administration in tumor-bearing athymic mice led to a dose- and time-dependent inhibition of growth of subcutaneous xenografts and to a marked reduction in the number and size of experimental liver metastases. In hepatic metastases of VEGF antibody-treated mice, neither blood vessels nor expression of the mouse KDR homologue flk-1 could be demonstrated. These data indicate that VEGF is a commonly expressed angiogenic factor in human colorectal cancer metastases, that VEGF receptors are up-regulated as a concomitant of hepatic tumorigenesis, and that modulation of VEGF gene expression or activity may represent a potentially effective antineoplastic therapy in colorectal cancer.

Vascular endothelial cell growth factor promotes tyrosine phosphorylation of mediators of signal transduction that contain SH2 domains. Association with endothelial cell proliferation

Vascular endothelial cell growth factor (VEGF), an endothelial cell-specific mitogen that plays an important role in angiogenesis, promotes the tyrosine phosphorylation of at least 11 proteins in bovine aortic endothelial cells (BAEC). Proteins immunoprecipitated from lysates of control- and VEGF-stimulated BAEC with antisera to phospholipase C-gamma (PLC-gamma) were fractionated by SDS-polyacrylamide gel electrophoresis and transferred to Immobilon-P. Evaluation of the Western blots with antisera to phosphotyrosine demonstrated that PLC-gamma and two proteins (100 and 85 kDa) that associate with PLC-gamma were phosphorylated in response to VEGF. By using antisera specific to other mediators of signal transduction that contain SH2 domains for immunoprecipitation, it was demonstrated that VEGF promotes phosphorylation of phosphatidylinositol 3-kinase, Ras GTPase activating protein (GAP), and the oncogenic adaptor protein NcK. Proteins of M(r) consistent with the VEGF receptors Flt-1 and Flk-1/KDR were also tyrosine phosphorylated in stimulated cells. Tyrosine-phosphorylated Nck, PLC-gamma, and two GAP-associated proteins, p190 and p62, were in GAP immunoprecipitates of VEGF-stimulated BAEC, and tyrosine-phosphorylated NcK was in phosphatidylinositol 3-kinase immunoprecipitates. These observations suggest that VEGF promotes formation of multimeric aggregates of VEGF receptors with proteins that contain SH2 domains and activate various signaling pathways. VEGF-promoted proliferation of endothelial cells and tyrosine phosphorylation of SH2 domain containing signaling molecules were inhibited by the tyrosine kinase inhibitor genistein.

Anatomy of the portal vein bifurcation: intra- versus extrahepatic location--implications for transjugular intrahepatic portosystemic shunts

PURPOSE

To delineate the relationship of the main portal vein bifurcation to the liver capsule, an anatomic study of the portal vein bifurcation was undertaken in 31 cadavers.

MATERIALS AND METHODS

The portal bifurcation was characterized as intrahepatic, extrahepatic, or at the liver capsule (junctional). When the bifurcation was extrahepatic, the exposed portions of the right and left portal veins were measured.

RESULTS

The portal bifurcation was intrahepatic in eight cadavers (25.8%), at the liver capsule in eight cadavers (25.8%), and extrahepatic in 15 cadavers (48.4%). The maximum lengths of exposed extrahepatic right and left portal veins were 3.0 cm and 2.5 cm, respectively.

CONCLUSION

These findings suggest that for transjugular intrahepatic portosystemic shunt placement, a portal vein puncture site 3 cm from the portal bifurcation will be intrahepatic in most cases.

Alternating hepatic intra-arterial floxuridine and fluorouracil: a less toxic regimen for treatment of liver metastases from colorectal cancer

Hepatic intra-arterial (HIA) infusion of floxuridine (FUDR) via an implanted pump has shown promise in the treatment of colorectal cancer metastasized to the liver. However, the potential benefit of this therapy may be offset by the high incidence of treatment-limiting biliary toxicity. Although weekly HIA bolus of fluorouracil (5-FU) is effective against metastatic colorectal cancer to the liver with no biliary toxicity, it is limited by systemic side effects. In December 1986, we began a phase II trial of alternating HIA FUDR and 5-FU via the implanted pump in an attempt to extend the duration of treatment by obviating the limiting biliary (FUDR) and systemic (5-FU) drug toxic effects. Patients received continuous HIA FUDR at 0.1 mg/kg of body weight per day on days 1 through 8 followed by an HIA bolus of 5-FU at 15 mg/kg given via the pump sideport on days 15, 22, and 29, with the cycle repeated every 35 days. Sixty-eight patients were enrolled in this trial, and 64 were fully evaluable. Of the 64 patients, 30 (47%) previously had received chemotherapy. Major response (complete response plus partial response) was observed in 32 (50%) of 64 patients, and the median survival from pump implantation in all patients was 22.4 months. In contrast to the experience with the single-agent HIA FUDR regimen, no patient had treatment terminated because of drug toxicity. Alternating HIA FUDR and 5-FU has efficacy similar to that of HIA FUDR given alone, but when closely monitored and adjusted appropriately, is not associated with toxic effects requiring treatment termination.

A model of reversible obstructive jaundice in the rat

A model of reversible, extrahepatic biliary obstruction is described. Vessel loop blockade of the biliary tree results in obstructive jaundice while removal of the exteriorized vessel loop provides internal biliary drainage without subsequent laparotomy. This technique combined with a system for chronic venous infusion and arterial blood sampling in the unrestrained rat is ideal for long-term metabolic studies of obstructive jaundice. Male Fisher 344 rats (275-350 g) underwent either the combined procedure of total biliary tract blockade and vascular access or sham operation. Mean serum bilirubin was significantly elevated (12.7 +/- 8.9 mg/dl) in the experimental group and following relief of biliary obstruction significantly dropped below 1 mg/dl in all animals except one. Concomitant changes in alkaline phosphatase, glutamate oxaloacetate transaminase, and glutamate pyruvate transaminase were seen. Experimental and control rats initially lost weight following laparotomy; however, mean body weight stabilized by the 5th postoperative day and was similar in both groups on the 10th postoperative day. This combined procedure is a simple, effective and reproducible method of obstructive jaundice.

Tumor necrosis factor and the acute metabolic response to tissue injury in man

Tumor necrosis factor (cachectin), a protein produced by monocytes and macrophages, has been implicated as an important mediator of the lethal effects of endotoxic shock and the cachexia of chronic infection. Recombinant human tumor necrosis factor alpha (rTNF) was given intravenously to patients as part of an antineoplastic trial. Fever, tachycardia, and at higher doses, hypotension occurred after a single injection of rTNF. Metabolic effects after rTNF administration were dose related and included enhanced energy expenditure with elevated CO2 production, increased whole body protein metabolism and peripheral amino acid efflux from the forearm, and decreased total arterial amino acid levels associated with a significant increase in plasma cortisol. Elevated serum triglycerides, as well as increased glycerol and free fatty acid turnover were seen, suggesting increased whole body lipolysis and fat utilization after rTNF. These findings indicate that administration of TNF in man reproduces many of the acute physiologic and metabolic responses to tissue injury, including energy substrate mobilization.

Hormonal and metabolic response to recombinant human tumor necrosis factor in rat: in vitro and in vivo

Tumor necrosis factor (TNF; cachectin) has been implicated as a mediator of the toxic manifestations of overwhelming bacterial infection as well as the chronic catabolic state of cancer cachexia. We have examined the acute metabolic and hormonal response after administration of recombinant human TNF in the rat. TNF given by intraperitoneal injection produced dose- and time-related increases in hepatic amino acid uptake, decreases in serum trace metal concentrations, and a pattern of endocrine hormone alterations characteristic of the acute phase response to tissue injury. In vitro zinc transport studies by rat hepatocytes cultured in the presence of TNF alone, or in combination with recombinant human interleukin 1, another mediator of the acute phase response, demonstrated that neither monokine was capable of directly stimulating zinc transport into cells. These findings suggest that TNF may function as an endogenous mediator of the early metabolic response to sepsis and that the trace metal changes induced by TNF in vivo may occur through a secondary mechanism.

Clinical pharmacology of recombinant human tumor necrosis factor in patients with advanced cancer

Twenty-six patients with advanced cancer refractory to standard therapy were treated with recombinant human tumor necrosis factor (rTNF) in a study aimed at determining the toxicity and tolerance of rTNF and at seeking evidence of antitumor activity. The study design involved two treatments per week for 4 weeks with alternating subcutaneous and intravenous (IV) administration, and weekly dose escalation through four levels in each patient. The dose range was 1 to 200 micrograms/m2 for IV bolus injection, and 5 to 250 micrograms/m2 for subcutaneous injection. Thirteen patients completed the full course. Early discontinuation of treatment was related to rTNF toxicity in seven cases. The major side effects were rigors, fever, headache, fatigue, and hypotension. Acute changes in granulocyte, lymphocyte, and monocyte counts, changes in serum zinc levels and plasma cortisol levels consistent with an acute phase response, and inflammation at the site of subcutaneous injection were also seen. At doses of 125 to 250 micrograms/m2, inflammation at the subcutaneous injection site was unacceptably severe. Minor changes were seen in hemostatic parameters. Hypotension was corrected by fluid administration and did not require treatment with vasopressors. Initial serum concentrations of rTNF were measured at five minutes after IV administration and were found to range from 2.5 ng/mL after a dose of 35 micrograms/m2 to 80 ng/mL after a dose of 200 micrograms/m2. The half-life of rTNF in the blood was 20 minutes. A decrease in lymph node size was observed in a patient with B cell lymphoma.

The acute metabolic effects of tumor necrosis factor administration in humans

It has been suggested that the monokine tumor necrosis factor (TNF) (cachectin) is responsible for metabolic abnormalities frequently accompanying malignant neoplasms. The acute metabolic effects of TNF in patients with cancer were studied. Subcutaneous administration of recombinant human TNF led to a rise in the C-reactive protein level (4.4 +/- 1.2 mg/dL vs 11.6 +/- 1.8 mg/dL) and a reduction in the serum zinc level (12.9 +/- 0.8 mumol/L vs 7.3 +/- 0.8 mumol/L [79 +/- 5 mg/dL vs 48 +/- 5 mg/dL]) (values are the mean +/- SEM). Forearm efflux of total amino acids more than doubled after intravenous TNF injection, principally because of increases in release of the gluconeogenic amino acids alanine and glutamine. Concomitantly, the arterial levels of alanine, glutamine, and total amino acids fell, indicating that TNF also stimulated the uptake of amino acids by other tissues. The observed amino acid pattern cannot be explained solely on the basis of measured changes in cortisol, glucagon, or insulin levels. These findings are discussed in relation to known alterations of amino acid metabolism in cancer-associated cachexia.

Modulation of endogenous hormone action by recombinant human tumor necrosis factor

Tumor necrosis factor (TNF) has been implicated in the toxic manifestations of overwhelming bacterial infection and in the tissue wasting that often accompanies prolonged infections and malignancy. We have examined a possible role of TNF in the early metabolic alterations following acute tissue injury or sepsis. Recombinant human TNF stimulated rat liver amino acid uptake up to 5-fold in vivo and there was a concomitant increase in plasma glucagon. In vitro TNF had no direct effect on hepatocyte amino acid uptake, but it markedly enhanced the stimulation of amino acid transport by glucagon, without an alteration in binding of glucagon to hepatocytes. This permissive effect of TNF on glucagon action represents an interrelationship between the immune and endocrine systems, and it may help to explain the mechanism of hormonal regulation of both the anabolic and catabolic responses to acute injury.

Protein synthesis in hepatocytes isolated from patients with gastrointestinal malignancy

To investigate the effect of remote and proximate cancer on hepatic protein metabolism, we determined rates of total protein synthesis by hepatocytes (HPS) isolated from 31 patients undergoing liver wedge biopsy: 7 patients with benign disease, 14 with gastric cancer, and 10 with colorectal cancer (5 of whom had liver metastases). Patients with malignant disease without weight loss had a threefold higher rate of total HPS (4,980 +/- 814 pmol/h per 10(5) viable cells) than patients with benign disease without weight loss (1,278 +/- 318 pmol/h per 10(5) viable cells, P less than 0.001). Among the patients with gastric cancer, eight with preoperative weight loss had lower rates of HPS (380 +/- 90 pmol/h per 10(5) viable cells) than those without weight loss (4,061 +/- 401 pmol/h per 10(5) viable cells, P less than 0.002). The highest rates of HPS were seen in patients with colorectal cancer with liver metastases (8,005 +/- 1,975 pmol/h per 10(5) viable cells) vs. colorectal cancer patients without liver metastases (3,060 +/- 575 pmol/h per 10(5) viable cells, P less than 0.03). These data indicate that modulation of hepatic protein synthesis occurs in malignancy in man. However, the stimulatory influence of the tumor-bearing state may be overridden by the inhibitory effects of cachexia.

Altered peripheral amino acid uptake in obstructive jaundice

To characterize amino acid metabolism in obstructive jaundice, the amino acid uptake in tissues of bile duct-ligated (BDL) rats was determined. Fischer 344 rats underwent either bile duct ligation or sham laparotomy and were pair fed for 72 hr. Amino acid uptake was determined in peripheral skeletal muscle (quadriceps femoris, soleus, and rectus abdominis), liver, blood, and other tissues by accumulation of alpha-[14C]-aminoisobutyric acid following intracardiac injection. Although total hepatic amino acid uptake was unaltered in the BDL animals compared with the sham-operated controls, amino acid uptake in peripheral skeletal muscle was significantly decreased in all muscle groups studied in the BDL rats. The relative concentration (percentage dose per gram normalized to the animal mass) for quadriceps femoris was 0.16 +/- 0.02 for BDL and 0.32 +/- 0.04 for sham-operated rats, P less than 0.005. Muscle protein was lower in BDL animals when compared with sham-operated rats (P less than 0.05). Total trunk blood amino acid levels were not significantly different in the two groups; however, there was a decreased serum level of branched-chain amino acids in the BDL group, P less than 0.05. No differences in plasma glucose or serum insulin were found in the two groups; lactate levels were lower in the BDL group, and plasma triglyceride levels were three times higher in the BDL animals. These data suggest that obstructive jaundice in the rat is associated with organ-specific metabolic abnormalities consistent with impaired peripheral amino acid uptake.

Comparison of hepatic protein synthesis in vivo versus in vitro in the tumor-bearing rat

We have used the model of the freshly isolated hepatocyte to study liver metabolism in a rat tumor model and have reported elevations in the rates of protein synthesis, gluconeogenesis, alanine transport, and oxygen utilization by the tumor-influenced hepatocyte. While the metabolic activity of the isolated hepatocyte has been taken to reflect metabolism in the in vivo state, this assumption has not been validated. In the present study, we measure hepatic protein synthesis in vivo using a flooding dose of tracer amino acid, and in vitro in hepatocytes freshly isolated from tumor-bearing (TB) and pair-fed control rats. Increased protein synthesis was observed for the TB rats using both methods of analysis. However, the degree of stimulation seen in the TB animals was much greater in the in vitro assay than in the in vivo approach, suggesting that absolute protein synthetic rates in vitro must be interpreted with caution when extrapolating to the in vivo state.

Impaired metabolic response to endotoxin in obstructive jaundice

Surgical management of extrahepatic cholestasis is frequently complicated by sepsis, which can be explained in part by diminished function of the reticuloendothelial system. We have explored the possibility that the metabolic response to infection may also be abnormal. Fischer 344 rats underwent either bile duct ligation (BDL) or sham operation and were studied 3 days after operation. Hepatic amino acid uptake measured in vivo by the accumulation of 14C-alpha-aminoisobutyric acid or in vitro by the rate of transport of 14C-alanine by isolated hepatocytes was unaltered in the BDL animals, while gluconeogenesis from alanine by viable hepatocytes from BDL rats was actually enhanced. However, the expected increase in hepatic amino acid uptake in response to endotoxin was diminished in the BDL animals. In addition, we observed impaired responses of the jaundiced animals to glucagon and interleukin-1, two mediators of the hepatic acute phase response to endotoxin. These data suggest that while hepatic amino acid transport is normal in the basal state, the rat with extrahepatic biliary obstruction does not respond appropriately to stress and that this defect cannot be explained solely on the basis of altered handling of endotoxin by the reticuloendothelial system.

Protein synthesis in the tumor-influenced hepatocyte

Total body protein turnover is elevated in the Fischer 344 rat bearing a subcutaneous transplantable methylcholanthrene-induced sarcoma. To assess the contribution of the liver, we have measured protein synthesis by hepatocytes freshly isolated from tumor-bearing animals over a range of tumor burdens and from sham-inoculated nontumor bearers. Synthetic rates of total hepatocyte protein were more than twofold greater in hepatocytes from tumor-bearing animals (P less than 0.005) and the increase was proportional to the tumor burden in individual animals (n = 19; r = 0.68; p less than 0.005). When compared with pair-fed nontumor bearers, the differences in rates of total hepatocyte protein synthesis reached statistical significance only when the tumor burden exceeded 5% of total body weight. The stimulation in synthetic rates applied equally to secretory and nonsecretory hepatocyte protein. Furthermore, a lack of net protein accrual in the livers of tumor-bearing animals suggests a concomitant increase in the rate of hepatic protein degradation.

Salt tolerance in cultured cells of Spartina pectinata

Suspension cultures with cell doubling times of ca. 2 days were developed from the halophytic grass Spartina pectinata. Maximum rates of exponential growth measured by direct cell counts and by total culture packed-cell-volume were not significantly reduced by NaCl up to 200 mM but dropped beyond this point. In contrast, total cell production over a one week culture cycle, by both measures, was reduced in a roughly linear fashion between 0 and 500 mM NaCl. The pattern of growth in relation to NaCl is very similar to that of previously described cell suspensions derived from another halophyte, Distichlis spicata. In the field the latter is much more salt tolerant. The basis for the whole plant differences is not clear. They do not appear to reflect effectiveness of cell based salt tolerance or the presence of salt glands, which are reported here for the first time in S. pectinata and are found on the leaves of both species.