Genomic CGH-assessed structural DNA alterations in rectal carcinoma as related to local recurrence following primary operation for cure.

Several factors determine overall outcome and possible local recurrence after curative surgery for rectal carcinoma. Surgical performance is usually believed to be the most pertinent factor, followed by adjuvant oncological treatment and tumor histopathology. However, chromosomal instability is common in colorectal cancer and tumor clones are assumed to differ in aggressiveness and potential of causing local recurrence. The aim of this study was, therefore, to evaluate if genetic alterations in primary rectal carcinoma are predictive of local recurrences. A large clinical database with linked bio-bank allowed for careful matching of two patient groups (R0) resected for rectal carcinoma. One group had developed early, isolated local recurrences and the other group seemed cured after 93 months follow-up. DNA from the primary tumors was analysed with array-CGH (comparative genomic hybridization) including 55,000 genomic probes. DNA from all primary tumors in both groups displayed previously reported and well-recognised DNA aberrations in colorectal carcinoma. Significant copy number gains were confirmed in the 4q31.1-31.22 region in DNA from tumors with subsequent local recurrence. Twenty-two affected genes in this region code for products with high relevance in tumor biology (p53 regulation, cell cycle activity, transcription). DNA from rectal carcinoma displayed well-known aberrations as described for colon carcinoma with no obvious prediction of local rectal recurrence. Gains in the 4q31.1-31.22 DNA region are highly potential for local recurrence despite R0 resection to be confirmed in larger patient materials.

The role of combined allelic imbalance and mutations of p53 in tumor progression and survival following surgery for colorectal carcinoma.

The role of p53 mutations in disease progression and survival of colorectal cancer is unclear, since numerous studies have reported different conclusions. However, few reports, if any, have evaluated disease progression and survival in relationship to 'functional' and 'non-functional' p53 status defined by genetic and molecular indications. Malignant colorectal tumors, from 72 unselected patients who underwent primary and potentially curative elective tumor resections, were either classified as p53 functional (p53+/+, p53+/-) or non-functional (p53-/-) based on DNA sequence analysis of all p53 exons, including determination of allelic imbalance of p53 (LOH), according to four DNA markers; 2 within the coding gene and two markers in the immediate flanking regions of p53. Tumor frequency of microsatellite instability was also analyzed according to Dukes' A-D stages. Dukes' staging predicted survival as expected, while the conceptual p53 status, functional p53 vs non-functional p53, did not clear-cut predict disease specific survival. p53 mutations alone or allelic imbalance inside the reading frame of the gene were unpredictive of survival, while allelic imbalance downstream of p53 predicted reduced survival (p < 0.05). The present study demonstrates that base mutations in combination with allelic imbalance within the reading frame of p53 do not predict survival or progression of colorectal cancer, while allelic imbalance upstream coding parts of the gene predicted disease-specific survival in univariate analysis. Thus, structural alterations within the gene seem less important than alterations in regions with potential control elements.

Anorexia and cachexia in prostaglandin EP1 and EP3 subtype receptor knockout mice bearing a tumor with high intrinsic PGE2 production and prostaglandin related cachexia.

Previous studies in our laboratory have suggested that prostaglandin (PG) E2 is involved in anorexia/cachexia development in MCG 101 tumor-bearing mice. However, the role of COX pathways in the pathogenesis of cancer anorexia/cachexia is not fully resolved. In the present study, we investigated the role of PGE receptors subtype EP1 and EP3 on the development of anorexia in MCG 101-bearing mice. Our results show that the absence of host EP1 or EP3 receptors did not alter the magnitude of anorexia in tumor-bearers. However, anorexia in tumor-bearing EP1 and EP3 knockouts was not improved by indomethacin treatment as observed in wild type tumor-bearers. By contrast, indomethacin improved body composition similar in EP1 and EP3 knockouts as well as in wild type tumor-bearing animals and tumor growth was retarded in EP1 and promoted in EP3 knock outs. Our results demonstrate that host EP1 and EP3 receptors are involved in the control of local tumor growth, which translates into anorexia, this being the main cause of metabolic adaptive alterations to explain weight loss in this model. Brain EP1 and EP3 subtype receptors do not seem to directly control anorexia, which leaves EP2 and EP4 as potential candidates.

Mutations and allelic loss of p53 in primary tumor DNA from potentially cured patients with colorectal carcinoma.

PURPOSE: To compare p53 alterations in survivors and nonsurvivors after surgery for colorectal cancer. PATIENTS AND METHODS: Twenty-nine potentially cured patients with colorectal carcinoma, without recurrent disease for more than 6 years after their primary surgery, were selected to match a group of 41 colorectal cancer patients with early metastatic spread to the liver. All patients were screened for mutations in the p53 gene, exons 5 to 9, by denaturing gradient gel electrophoresis and subsequent sequencing. RESULTS: The frequency of p53 mutations was significantly different in cured patients (60%) compared with patients with early relapse (41%, P <.05). A significant difference was found in the distribution of mutations, indicating that potentially cured patients had a different proportion of mutations in conserved regions of p53 (P =.02). This difference was explained by a significantly different frequency of mutations in exon 8 (40% v 15%, P =.03), which is part of the conserved region V. All mutations in region V were codon 273 mutations in cured patients, whereas three of four mutations were located in codon 273 in patients with metastatic disease. Allelic loss of p53 (loss of heterozygosity [LOH]) was demonstrated in 26% of the cured patients and in 39% of patients with metastatic disease (P =.36). The combination of mutation and LOH of p53 was the same (17%) in both groups. CONCLUSION: A large number of p53 mutations in colorectal cancer do not promote disease progression. Some mutations, particularly within conserved regions, may even counteract negative functional effects of other p53 structural alterations. A complete loss of p53 function was not related to survival or progression after curative operation of colorectal carcinoma.

Cytokine and cyclooxygenase-2 protein in brain areas of tumor-bearing mice with prostanoid-related anorexia.

Evidence suggests that cytokines in the central nervous system are mediators behind anorexia in tumor-bearing hosts. We have therefore evaluated, by immunohistochemical image analyses, time course changes of interleukin (IL)-1beta, IL-6, tumor necrosis factor (TNF) alpha, IL-6 receptor (gp130), IL-1 receptor I, and cyclooxygenase (Cox)-2 protein in brain cortex, hippocampus and the ventromedial hypothalamic nucleus (VMH) in tumor-bearing mice with prostanoid-related anorexia. Pair-fed non-tumor-bearing mice were used as controls. Prostaglandin E(2) was provided systemically to freely fed, non-tumor-bearing mice to confirm a role for prostanoids in modulation of brain cytokines and food intake. Time course changes of IL-1beta were significantly different between tumor-bearing mice and pair-fed controls in the hippocampus but not in the VMH. TNF-alpha in the hippocampus and VMH did not show any significant difference between tumor-bearing mice and pair-fed controls, whereas TNF-alpha showed a small increase over time in brain VMH. IL-6 content did not show any significant alterations among tumor-bearing and pair-fed mice but increased significantly over time in both the study and control group. Cox-2 in brain hippocampus and VMH showed a statistically significant rise in both tumor-bearing and pair-fed controls, with no difference between animal groups. Systemic provision of exogenous PGE(2) to non-tumor-bearing mice altered brain cytokines significantly in the hippocampus and VMH with associated changes in food intake. Our results demonstrate that some differences (IL-1beta) occurred in brain cytokines comparing tumor-bearing and pair-fed, non-tumor-bearing mice but within unexpected decreased levels in brain tissue from tumor-bearing mice. Surprisingly, many time course changes in brain cytokines were similarly altered in tumor-bearing and pair-fed mice. Our observations do not support that up-regulation of brain cytokines explains or promotes anorexia in cancer disease. Rather, cytokine and Cox-dependent alterations in brain tissue seemed to be secondary to a decline in food intake and related to subsequent stress hormone activities.

Indomethacin and telomerase activity in tumor growth retardation.

It is well-recognized that cycloogygenase inhibitors attenuate tumor growth in tumor models, although underlying mechanisms are unclear. In the present study we report that indomethacin retards MCG-101 tumor growth on mice by induction of apoptosis/necrosis and inhibits telomere elongation. The inhibition of telomerase activity by NSAIDs (indomethacin, mobic, sulindac sulfone, suramin) was, however, not a universal finding, since a mouse melanoma (K1735-M2) did not respond. By contrast, a human cell line of colon carcinoma origin (HT-29), responded by both retarded growth and telomerase activity despite a low intrinsic production of prostaglandins, mainly PGE2. Therefore, it is not likely that indomethacin inhibition of tumor growth and telomere elongation is directly related to Cox-1/Cox-2 activities in tumor cells. Also, NSAIDs at 25 microM (sulindac sulfone) decreased growth and telomerase activity in MCG-101 cells, without any effects on PGE2 production, while ibuprofen reduced PGE2 production but had no effect on growth or telomerase activity. Our results demonstrate that cyclooxygenase inhibitors can retard tumor growth both in murine tumors and in human tumor cells by inhibition of telomerase activity in addition to previously recognized mechanisms as induction of apoptosis, inhibition of cell proliferation, influence on the expression of growth factors around growing tumors and attenuation of neoangiogenesis.

P53 mutations in primary tumors and subsequent liver metastases are related to survival in patients with colorectal carcinoma who undergo liver resection.

BACKGROUND: The appearance of p53 mutations in colorectal carcinoma was determined, independent of differentiation and tumor stage of the primary tumors, in relation to the survival of patients who were scheduled to undergo liver resection. METHODS: Tumor material was analyzed for p53 mutations in primary colorectal tumors and subsequent liver metastases from 41 consecutive patients who were scheduled to undergo surgical liver resection. DNA sequencing and immunohistochemical staining of p53 protein within tumor nuclei were performed. RESULTS: Primary tumors displayed p53 mutations within exons 5-9 in 41% of patients. No mutations were found in exons 4, 10, or 11. Forty-one percent of metastatic lesions had the same single mutation that was found in the primary tumor, whereas 11% of metastatic lesions had one additional mutation within exons 5-9; 22% had mutations only in their liver metastases, whereas corresponding primary tumors displayed wild-type p53. None of the patients had mutated p53 in their primary tumor and wild type in their metastases. Survival after undergoing liver resection was correlated negatively (P < 0.05-0.01) with Duke Stages A-D classification of the primary tumors, tumor differentiation, and radicality (> 0.7-0.8 mm) of resected liver metastases. CONCLUSIONS: The presence of p53 mutations in patients with metastatic lesions was related significantly (P < 0.003) to better survival after the patients underwent liver resection compared with patients with wild type p53 in their metastatic lesions. This finding was not related to covariates, such as Duke classification, tumor differentiation, type of liver metastasis, or metastatic radicality during resections. Explanations for this unexpected finding remain unclear, although the authors speculate that occult tumor cells with p53 mutations may be less responsive to growth factor(s) exposure during hepatic regeneration after resection.

Effect of cyclooxygenase and nitric oxide synthase inhibitors on tumor growth in mouse tumor models with and without cancer cachexia related to prostanoids.

The potential interaction between cyclooxygenase (Cox) and NO metabolic pathways in the control of local tumor growth was evaluated. Mice bearing either a sarcoma-derived tumor (C57B1; MCG 101) or a malignant melanoma (C3H/HeN; K1735-M2) were used. These models were principally different because they demonstrate, in tumor hosts, conditions with and without cancer cachexia, seemingly related to high and low production of prostanoids, respectively. Cox inhibitors (Cox-1 and Cox-2) decreased tumor growth by 35-40% in MCG 101-bearing mice but had no such effect on melanoma-bearing mice, despite the expression of the Cox-2 protein in melanoma cells. Indomethacin reduced prostanoid production in both tumor (MCG 101) and host tissues and reduced tumor cell proliferation, mainly in vivo. Nitric oxide synthase (NOS) inhibitors (N(omega)-nitro-L-arginine methyl ester and N(omega)-nitro-L-arginine) reduced tumor growth in vivo by approximately 50% in both tumor models. Tumor growth reduction, related to NOS inhibition, was unrelated to prostanoid production and was an in vivo phenomenon in both tumor models. Specific inhibitors of inducible NOS activity, unexpectedly, had no effect in any tumor model, although inducible NOS protein was present in tumor tissues in large amounts. A combination of Cox and NOS inhibitors had no additive effect on tumor growth (MCG 101). Cox inhibition increased tumor tissue (MCG 101) expression of cNOS mRNA but had no significant effect on tumor tissue expression of the transferrin receptor, vascular endothelial growth factor, or basic fibroblast growth factor. NOS inhibition increased tumor tissue content of cNOS mRNA but showed as well a trend to increase mRNA content of the transferrin receptor and vascular endothelial growth factor. Our results suggest that NOS inhibitors can decrease the local growth of tumors that are either responsive or unresponsive to Cox inhibition. This effect may reflect cross-talk between Cox and NOS pathways within or among tumor cells, or it may represent unrelated effects on tumor and host cells. Whether NO inhibition may be used therapeutically in clinical tumors that are unresponsive to eicosanoid intervention remains to be evaluated.

Molecular cloning and expression of a pituitary gland protein modulating intestinal fluid secretion.

Antisecretory factor (AF) is a protein known to inhibit intestinal fluid secretion induced by cholera toxin. cDNA clones, expressing immunoreactivity to AF were isolated from a human pituitary gland library and sequenced. The sequence contained 1309 base pairs plus a poly(A) tail; Northern blot analysis of pituitary RNA confirmed this size. One large open reading frame was found to code for 382 amino acids. The protein was expressed in pGEX-lambda 1T/Escherichia coli and purified. The recombinant AF was extremely potent, 9 ng (2.10(-13) mol), giving a significant antisecretory activity against cholera toxin-induced fluid secretion in rat. Antiserum against recombinant AF was used in immunohistochemical and Western blot analysis. Sections from human pituitary glands manifested specific intracellular staining in cells exclusively located in the anterior part. Both recombinant AF and AF extracted from pituitary gland appeared in SDS-polyacrylamide to have a molecular mass of 60 kDa, although the renal value was 41 kDa. The protein sequence manifested homology (29% identity) with one protein, a putative Saccharomyces cerevisiae 30-kDa protein of unknown function.

Effects related to indomethacin prolonged survival and decreased tumor-growth in a mouse-tumor model with cytokine dependent cancer cachexia.

Tumor-bearing mice with two different locally growing malignant tumors (epithelial like, MCG 101; malignant melanoma, K1735-M2) were used to evaluate the putative role of prostaglandins for survival and local tumor growth in experimental cancer. Daily systemic injections of indomethacin (1 mu g/g bw) were used to block prostaglandin production in normal and T-cell deficient tumor-bearing nude mice. Tumor progression was determined by measurements of tumor weight, DNA-synthesis, cell cycle kinetics in vivo and in vitro (flow cytometry), tumor tissue concentrations of polyamines (putrescine, spermidine, spermine) and tumor tissue gene expression of growth regulating factors (IL-1 alpha, IL-6, TNF alpha, A,B-PDGF, EGF, VEGF, bFGF, TGF beta(3), angiogenin and transferrin receptor). Tumor tissue content of von Willebrandt factor VIII was estimated by immunohistochemistry. Indomethacin had no effect on survival, host nutritional state or local tumor growth in mice bearing the malignant melanoma with low PGE(2) production. In contrast, indomethacin prolonged survival, improved cachexia and decreased tumor growth in mice bearing the MCG 101 tumor with hundredfold higher prostaglandin tumor production, leading to elevated liver and muscle tissue as well as plasma concentrations of PGE(2). Indomethacin inhibited almost completely the high tumor PGE(2) production in MCG tumors, leading to prolonged potential doubling time for tumor growth in vivo, and a trend to decreased tumor tissue concentration of polyamines (spermidine). Indomethacin had no inhibitory effect on tumor cell proliferation in vitro, although PGE(2) production was decreased by 75%. The effect of indomethacin in vivo was independent of T-cells and was observed with similar magnitude irrespective of the number of MCG cells (10(4)-10(6)) implanted or the site of implantation (s.c., i.p., liver, lung, skeletal muscles). Tumor growth inhibition by indomethacin was not intrinsically transferable by tumor cells from indomethacin treated tumor-animals. Tumor expression of mRNA for several growth regulating factors were either increased (IL-6, TNF alpha, GM-CSF, TGF beta(3)) unchanged (EGF, VEGF, PDGF A,B, IL-1 alpha, transferrin receptor) or decreased (b-FGF and angiogenin) (p<0.05) by indomethacin treatment of MCG mice. Decreased tumor content of von Willebrandt factor VIII in combination with an attenuated tumor vasculature were associated with decreased tumor growth (p<0.05). Our results confirm that high tumor production of prostaglandins was related to reduced survival. Tumor prostaglandins probably promote local tumor growth by stimulation of tumor surrounding cells to produce growth factor(s) for tumor angiogenesis including tumor and matrix cell proliferation unrelated to immune cells.

Anti-inflammatory treatment may prolong survival in undernourished patients with metastatic solid tumors.

Eicosanoids may be important factors for tumor cell proliferation, metastatic formation, and development of cancer cachexia. The present study has evaluated the effect of anti-inflammatory treatment on tumor progression in clinical cancer. Patients (n = 135) with insidious or overt malnutrition due to generalized malignancy (various kinds of solid tumors) and an expected survival of more than 6 months were randomized by a computer-based algorithm to receive placebo, prednisolone (10 mg twice daily), or indomethacin (50 mg twice daily) p.o. until death. Patient groups were stratified in the randomization procedure for sex, tumor type, stage, nutritional state, and previous tumor treatment, and biochemical, physiological, and some functional variables (Karnowsky index, fatigue and pain score). A majority of these variables was then registered during the follow-up. Indomethacin and prednisolone treatment maintained Karnowsky index, while placebo-treated patients experienced a decreased index. Indomethacin-treated patients suffered less pain and consumed less additional analgetics compared to the other patient groups. Indomethacin prolonged mean survival compared to placebo-treated patients from 250 +/- 28 days to 510 +/- 28 days (P < 0.05). Survival analysis on observations from all patients treated with either indomethacin or prednisolone demonstrated a significantly prolonged survival by anti-inflammatory treatment compared to placebo treatment (log rank, P < 0.03). The results suggest that not only may prostaglandin synthesis inhibition offer palliative support to patients with solid advanced cancer, but it may also impact on pathways that ultimately determine outcome.

Expression of interleukin-6 in tumor-bearing mice with cytokine dependent cachexia.

Increased production of IL-6 in tumor-bearing mice occured in a variety of host-tissues including tumor tissue. Elevated IL-6 transcription in tumor-bearing mice occured in the tumor, liver, kidney and the small intestine, and was associated with increased concentration in the circulation of bioactive IL-6 of normal size (almost-equal-to 20 000 kDa) in addition with two larger but biologically inactive serum fractions containing immune-reactive IL-6. These inactive complexes were not explained by circulating inhibitor(s). The occurrence of differently sized tumor and host-tissue IL-6 mRNAs were dependent on the subcellular location (nuclear, ribosomal, cytoplasm). the tissue type and the kind of cellular stimulation. In tumor-tissue, IL-6 was produced to the highest concentration in tumor cells, followed by inflammatory and endothelial cells respectively, but IL-6 did not seem to represent an autocrine growth factor loop as earlier reported by us for both IL-1alpha and TNFalpha in the present tumor model. In contrast, evidence supported that IL-6 acted as a paracrinic factor in this model stimulated by some other host-derived factor(s).

Role of endogenous tumor necrosis factor alpha and interleukin 1 for experimental tumor growth and the development of cancer cachexia.

The aim of this study was to evaluate to what extent tumor necrosis factor alpha (TNF-alpha) and interleukin 1 may explain the development of experimental cancer cachexia. For this purpose, C57BL/6J mice bearing a transplantable low differentiated rapidly growing tumor were passively immunized every other day with rabbit or rat neutralizing immunoglobulins against either TNF-alpha (anti-TNF) or against an interleukin 1 receptor (anti-IL-1r). Anti-IL-1r in itself had no agonistic effect to the type I, T-cell/fibroblast IL-receptor. Tumor-bearing mice receiving either preimmune antiserum or nonimmune rat hybridoma IgG served as controls. Anti-TNF and anti-IL-1r inhibited tumor growth significantly, as measured by a lower wet and dry tumor weight at the end of 11 days of antiserum treatment (P less than 0.05). The acute phase response in tumor-bearing animals, measured as an increase in liver weight, hepatic RNA content, and increases in plasma concentrations of circulating IL-6, serum amyloid P, transferrin, complement (C3), and a decrease in plasma albumin, were unaffected by the specific antiserum treatments. Food intake, which declined significantly in pre/nonimmune injected tumor-bearing controls, was significantly improved in tumor-bearing animals immunized against TNF-alpha or the IL-1r. Whole body lipid content showed a trend to improvement in specifically immunized animals (P less than 0.07). The effects on whole body fat-free dry weight were insignificant, although numerically higher in specifically immunized tumor-bearing animals. The combination of anti-TNF and anti-IL-1r antiserum had no additive effects compared to single antiserum treatment suggesting that the two antibody treatments acted through a common mechanism. Cultured tumor cells, established from growing tumors, were sensitive to anti-TNF and anti-IL-1r, which both reduced tumor growth in vitro. This inhibitory effect by the antiserum could in part be reversed by the addition of recombinant IL-1 alpha and TNF alpha. We conclude that both TNF and IL-1 are involved in tumor growth and thus the progression of cancer cachexia. It seems as if the role of TNF and IL-1 was to promote tumor growth rather than restrict tumor growth in the present model. In this sense both TNF and IL-1 may act as tumor growth factors.

Tumor necrosis factor-alpha and interleukin-1 alpha production in cachectic, tumor-bearing mice.

Weight-stable mice bearing a syngeneic, methylcholanthrene-induced, rapidly growing tumor lost approximately 22% of their lean tissue, became significantly hypoalbuminemic and had a marked increase in serum amyloid P concentrations during progressive tumor growth. Tumors from cachectic mice were producing both TNF-alpha and IL-1 alpha in vivo as documented by the presence of TNF-alpha and IL-1 alpha mRNA and immune-reactive protein for IL-1 alpha. Only spleens from tumor-bearing mice had statistically significantly elevated quantities of IL-1 mRNA. In general, alterations in tissue concentrations of IL-1 mRNA in tumor-bearing animals agreed qualitatively with those found in endotoxin-stimulated, non-tumor-bearing control mice. However, endotoxin-stimulated mice had significantly elevated tissue concentrations of TNF mRNA in spleen and livers, while TNF mRNA levels were not significantly increased in any host tissues. Cytokine mRNA levels in tumor tissue were not higher than those found constitutively in various tissues from non-tumor-bearing control animals. Plasma from tumor-bearing mice and endotoxin-stimulated controls contained high levels of IL-6 but low (endotoxin-stim.) or no measurable levels (tumor-bearing) of either IL-1 or TNF. When tumor cells from cachectic mice were placed into long-term cell culture, immune reactive TNF-alpha and IL-1 alpha were produced, but IL-6 bioactivity ws not produced in measurable amounts.

Increased degradation of albumin in cancer is not due to conformational or chemical modifications in the albumin molecule.

This study has evaluated whether increased albumin degradation in a tumor-bearing host is dependent on previously recognized chemical and environmental modifications in the albumin molecule as observed by others and ourselves. For the purpose, adult sarcoma-bearing mice with increased albumin degradation and electrophoretic heterogeneity were used and compared to freely fed (FF) or food restricted control animals. Food restricted control animals such as pair-fed (PF) and pair-weighed (PW) served to match the anorexia and malnutrition observed in tumor-bearing animals. The serum albumin concentration was decreased (P less than 0.05) in tumor-bearing animals (33 +/- 5 g/liter) compared to pair-fed (40 +/- 3), pair-weighed (41 +/- 4), and freely fed control mice (43 +/- 3). Isoelectric focusing of plasma between pH 3 and 10 and pH 4 and 6.5 confirmed a different isoelectric point for albumin in tumor-bearing animals compared to control animals. Albumin degradation was 33% higher in tumor-bearing mice compared to freely fed controls (P less than 0.01). Tumor-bearing animals had also significantly increased turnover of albumin compared to all control animals (0.13 +/- 0.022 mg/hr/g animal vs 0.05 +/- 0.008 mg/hr/g in PW; 0.08 +/- 0.009 in PF, and 0.09 +/- 0.007 in FF). The acidic fraction of albumin had a more rapid fractional turnover than the more basic components in both tumor-bearing and control animals. However, both the anodal and the cathodal albumin in tumor-bearing mice had a higher turnover compared with corresponding fractions of albumin from control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Protein synthesis, myosin ATPase activity and myofibrillar protein composition in hearts from tumour-bearing rats and mice.

Growing rats and adult weight-stable mice bearing a transplantable methylcholanthrene-induced sarcoma were compared with animals with various states of malnutrition. Heart protein synthesis was measured in vivo. Myocardial RNA, myofibrillar protein composition and the Ca2+-activated ATPase activity in heavy chains of native myosin were measured. 'Fingerprints' were made from myosin by trypsin treatment to evaluate possible structural changes in the protein. Cardiac protein-synthesis rate was decreased by 20% in growing tumour-bearing rats, by 35% in protein-malnourished (rats) and by 47% in starved rats, compared with freely fed controls (P less than 0.05). Adult tumour-bearing mice showed no significant decrease in myocardial protein synthesis. Pair-weighed control mice had significantly depressed heart protein synthesis. Protein translational efficiency was maintained in both tumour-bearing rats and mice, but was decreased in several groups of malnourished control animals. The Ca2+-activated myosin ATPase activity was decreased in all groups of malnourished animals, including tumour-bearing mice and rats, without any evidence of a change in cardiac isomyosin composition. We conclude that loss of cardiac muscle mass in tumour disease is communicated by both depressed synthesis and increased degradation largely owing to anorexia and host malnutrition. Increased adrenergic sensitivity in hearts from tumour-bearing and malnourished animals is not communicated by increased Ca2+-activated ATPase activity. This may be down-regulated in all groups with malnutrition, without any observable alterations in the isomyosin profile.

Appearance of hybridoma growth factor/interleukin-6 in the serum of mice bearing a methylcholanthrene-induced sarcoma.

Serum concentrations of hybridoma growth factor/interleukin-6 progressively increased in mice bearing a transplantable methylcholanthrene-induced sarcoma with tumor growth. Elevated HGF/interleukin-6 concentrations were also positively correlated with increased serum concentrations of the hepatic acute phase reactant protein, amyloid P. Daily Indomethacin treatment of sarcoma-bearing mice prolonged survival and reduced the magnitude of the serum amyloid P response, but failed to attenuate either tumor growth or serum HGF/interleukin-6 responses. Since previous studies have demonstrated that neither interleukin-1 nor tumor necrosis factor-alpha can be detected in the serum of these sarcoma-bearing mice, and that HGF/interleukin-6 is a principal mediator of the hepatic acute phase response, we conclude that circulating HGF/interleukin-6 may contribute significantly to the host responses which accompany experimentally-introduced cancer. Furthermore, prostanoid inhibition does not appear to regulate the synthesis and release of HGF/interleukin-6 during tumor growth.

Plasma protein synthesis in experimental cancer compared to paraneoplastic conditions, including monokine administration.

During tumor growth, there are characteristic alterations in the concentration and synthesis of various plasma proteins. The purpose of this study was to evaluate whether these changes are unique to a tumor-bearing state, or rather, they represent a generalized response to a paraneoplastic state mediated by the release of monokines or protein-calorie malnutrition. Plasma protein synthesis and concentrations in mice bearing a transplantable fibrosarcoma were compared to animals receiving either a terpentine abscess, Corynebacterium parvum administration, calorie-protein depletion, or administration of the recombinant-derived monokines, murine interleukin 1 alpha or human tumor necrosis factor-alpha. Tumor-bearing animals showed a significant increase in total plasma protein synthesis that was similar in magnitude to the increase seen following a terpentine abscess or after administration of interleukin 1 or tumor necrosis factor-alpha. Similarly, the pattern of protein synthesis and concentration, as determined by isoelectric focusing or sodium dodecyl sulphate-polyacrylamide gel electrophoresis, were similar, albeit not identical, among tumor-bearing animals and those receiving either a terpentine abscess, C. parvum and monokine administration. Serum amyloid P concentrations were markedly elevated in tumor-bearing animals, as they were in animals after a sterile abscess and following interleukin 1 administration, as well as to a lesser extent tumor necrosis factor-alpha administration. We can therefore conclude that the majority of changes in plasma protein concentration and synthesis seen in this tumor-bearing model are similar to those seen during an acute inflammation and can be reproduced to a large extent by the administration of the monokines, interleukin 1 alpha or tumor necrosis factor-alpha.

Down-regulation of interleukin 1 production by macrophages of sarcoma-bearing mice.

Peritoneal macrophages from mice bearing a transplantable methylcholanthrene-induced sarcoma produced progressively less IL 1 as tumor burden increased. The loss of activity was not explained by the production of any inhibitor of the mouse thymocyte comitogen bioassay. Immune precipitation with a polyclonal antibody confirmed the decline in IL 1 appearance. Although tumor-bearing animals lost approximately 17% of their carcass mass, the reduced production of IL 1 was not satisfactorily explained by coexistent malnutrition, since similarly depleted non-tumor-bearing mice were capable of producing IL 1. In addition to an altered IL 1 production by macrophages of tumor-bearing mice, SDS-polyacrylamide gel electrophoresis and autoradiography revealed that the pattern of secretory protein synthesis from LPS-stimulated and unstimulated peritoneal macrophages differed between tumor-bearing and control animals. Administration of LPS to tumor-bearing mice early after tumor transplantation resulted in reduced tumor growth and prevented the down-regulation of in vitro IL 1 production by peritoneal macrophages. These findings demonstrate a specific defect in IL 1 production associated with increasing tumor burden. Further studies are required to determine whether this defect in IL 1 synthesis contributes to the increased tumor growth.