A high level of prostaglandin E2 (PGE2) in the portal vein suppresses liver-associated immunity and promotes liver metastases

Comparison Between the Effects of Intravenous Morphine, Tramadol, and Ketorolac on Stress and Immune Responses in Patients Undergoing Modified Radical Mastectomy

OBJECTIVES

Analgesics had been suspected of impairing various immune functions either directly or indirectly. Our primary objective was to compare the effects of intravenous (IV) morphine, tramadol, and ketorolac on stress and immune responses in patients who underwent modified radical mastectomy.

PATIENTS

Sixty patients randomly assigned to receive IV morphine 5 mg (group M, n=20), tramadol 100 mg (group T, n=20), or ketorolac 60 mg (group K, n=20) at the end of surgery.

METHODS

Serum cortisol, prolactin were measured immediately, 40 minutes, and 24 hours postoperatively. Expressions of peripheral T lymphocytes (CD3, CD3CD4, CD3CD8) and natural killer cells (CD3, CD56) were measured as percentages of total lymphocytes by flow cytometry immediately, 90 minutes, and 24 hours postoperatively.

RESULTS

After 40 minutes, cortisol level increased but prolactin decreased significantly (P=0.001), then both decreased after 24 hours (P=0.001) compared with baseline within the 3 groups. CD3, CD4, CD8, and CD56 significantly decreased at 90 minutes and 24 hours (P≤0.033) compared with baseline in the 3 groups. CD4, CD8, and CD56 significantly decreased in group M, compared with group T and K (P≤0.016) and CD3, CD8, and CD56 in group T compared with group K at 90 minutes (P≤0.024) postoperatively. After 24 hours, CD4, and CD8 decreased in group M compared with group T (P≤0.048) and CD4 and CD56 in groups M and T compared with group K (P≤0.049).

CONCLUSIONS

IV morphine, tramadol, and ketorolac suppressed stress and immune responses. Ketorolac was the least immunosuppressive among the 3 drugs.

Neutrophil-lymphocyte and platelet-lymphocyte ratio in patients after resection for hepato-pancreatico-biliary malignancies

BACKGROUND AND OBJECTIVES

We sought to determine whether Neutrophil-lymphocyte ratio (NLR) or platelet-lymphocyte ratio (PLR) were associated with outcomes of patients undergoing surgery for a hepatopancreatico-biliary (HPB) malignancy.

METHOD

Between 2000 and 2013, 452 patients who underwent an HPB procedure for a malignant indication were identified. Clinicopathological characteristics, NLR, and PLR, as well as short- and long-term outcomes were analyzed. High NLR and PLR were classified using a cut-off value of 5 and 190, respectively, based on ROC curve analysis.

RESULTS

Patients with low versus high NLR and PLR had similar baseline characteristics with regard to performance status and tumor stage (all P > 0.05). Elevated PLR (HR = 1.40) tends to be association with shorter recurrence-free survival (RFS) (P = 0.05), whereas NLR was not a predictor of shorter RFS. Differently, both elevated NLR (HR = 1.94) and PLR (HR = 1.79) were associated with worse overall survival (OS) (both P < 0.05). Patients with NLR ≥5 and those with PLR ≥190 had a significantly shorter OS compared to patients with NLR <5 and PLR <190, respectively (log-rank test, both P < 0.05). Moreover, patients who had both NLR and PLR elevated had worse OS compared to patients with either one or none inflammatory markers elevated (log-rank P = 0.02).

CONCLUSION

Elevated NLR and PLR were predictors of worse long-term outcome among patients with HPB malignancy undergoing resection.

Intraoperative use of ketorolac or diclofenac is associated with improved disease-free survival and overall survival in conservative breast cancer surgery

BACKGROUND

An association between the use of non-steroidal anti-inflammatory drugs (NSAIDs) and better outcome after mastectomy and lung surgery for cancer has been recently suggested. In a retrospective analysis, we investigated the association between intraoperative NSAIDs use in conservative breast cancer surgery and breast cancer disease-free survival (DFS). Similarly, we also evaluated the association between breast cancer DFS and preoperative neutrophil:lymphocyte ratio (NLR).

METHODS

A retrospective analysis of a single-centre cohort was performed in breast cancer patients (n=720) with uni- and multivariate analyses, using a Cox regression model.

RESULTS

In conservative breast cancer surgery, the intraoperative use of NSAIDs (ketorolac or diclofenac) was associated with an improved DFS {hazard ratio (HR)=0.57 [95% confidence interval (CI): 0.37-0.89], P=0.01} and an improved overall survival (OS) [HR=0.35 (95% CI: 0.17-0.70), P=0.03]. In these patients, an NLR >3.3 (identified by a receiver-operating characteristic curve) was associated with a shorter DFS [HR=1.99 (95% CI: 1.16-3.41), P=0.01] and OS [HR=2.35 (95% CI: 1.02-5.43), P=0.046].

CONCLUSIONS

Intraoperative NSAIDs and higher preoperative NLR are associated with improved outcome in conservative breast cancer surgery. Prospective, randomized trials to evaluate if these associations are causal are warranted.

Does regional anaesthesia and analgesia or opioid analgesia influence recurrence after primary cancer surgery? An update of available evidence

Cancer continues to be a key cause of morbidity and mortality worldwide and its overall incidence continues to increase. Anaesthetists are increasingly faced with the challenge of managing cancer patients, for surgical resection to debulk or excise the primary tumour, or for surgical emergencies in patients on chemotherapy or for the analgesic management of disease- or treatment-related chronic pain. Metastatic recurrence is a concern. Surgery and a number of perioperative factors are suspected to accelerate tumour growth and potentially increase the risk of metastatic recurrence. Retrospective analyses have suggested an association between anaesthetic technique and cancer outcomes, and anaesthetists have sought to ameliorate the consequences of surgical trauma and minimise the impact of anaesthetic interventions. Just how anaesthesia and analgesia impact cancer recurrence and consequent survival is very topical, as understanding the potential mechanisms and interactions has an impact on the anaesthetist's ability to contribute to the successful outcome of oncological interventions. The outcome of ongoing, prospective, randomized trials are awaited with interest.

Neutrophil:lymphocyte ratio and intraoperative use of ketorolac or diclofenac are prognostic factors in different cohorts of patients undergoing breast, lung, and kidney cancer surgery

BACKGROUND

Inflammation is associated with a worse outcome in cancer and neutrophil:lymphocyte ratio (NLR) is a strong prognostic value. In cancer, nonsteroidal anti-inflammatory drugs (NSAIDs) could be of interest. We investigated the prognostic significance of NLR and the impact of intraoperative NSAIDs in cancer surgeries.

METHODS

We performed an observational study in early breast, kidney, and lung cancers (357, 227, and 255 patients) with uni- and multivariate analyses (Cox model).

RESULTS

In breast cancer (Centre 1), NLR ≥ 4 is associated with a higher risk of relapse (hazards ratio (HR) = 2.41; 95 % confidence interval (CI) 1.01-5.76; P = 0.048). In breast cancer (Centre 2), NLR ≥ 3 is associated with a higher risk of relapse (HR = 4.6; 95 % CI 1.09-19.1; P = 0.04) and higher mortality (HR = 4.0; 95 % CI 1.12-14.3; P = 0.03). In kidney cancer, NLR ≥ 5 is associated with a higher risk of relapse (HR = 1.63; 95 % CI 1.00-2.66; P = 0.05) and higher mortality (HR = 1.67; 95 % CI 1.0-2.81; P = 0.05). In lung cancer, NLR ≥ 5 is associated with higher mortality (HR = 1.45; 95 % CI 1.02-2.06; P = 0.04). The intraoperative use of NSAIDs in breast cancer patients (Centre 1) is associated with a reduced recurrence rate (HR = 0.17; 95 % CI 0.04-0.43; P = 0.0002) and a lower mortality (HR = 0.25; 95 % CI 1.08-0.75; P = 0.01). NSAIDs use at the beginning of the surgery is independently associated with a lower metastases risk after lung cancer surgery (HR = 0.16; 95 % CI 0.04-0.63; P = 0.009). Ketorolac use is independently associated with longer survival (HR = 0.55; 95 % CI 0.31-0.95; P = 0.03).

CONCLUSIONS

In these cohorts, these analyses show that NLR is a strong perioperative prognosis factor for breast, lung, and kidney cancers. In this context, intraoperative NSAIDs administration could be associated with a better outcome.

PGE2 suppresses NK activity in vivo directly and through adrenal hormones: effects that cannot be reflected by ex vivo assessment of NK cytotoxicity

Surgery can suppress in vivo levels of NK cell cytotoxicity (NKCC) through various mechanisms, including catecholamine-, glucocorticoid (CORT)-, and prostaglandin (PG)-mediated responses. However, PGs are synthesized locally following tissue damage, driving proinflammatory and CORT responses, while their systemic levels are often unaffected. Thus, we herein studied the role of adrenal factors in mediating in vivo effects of PGs on NKCC, using adrenalectomized and sham-operated F344 rats subjected to surgery or PGE(2) administration. In vivo and ex vivo approaches were employed, based on intravenous administration of the NK-sensitive MADB106 tumor line, and based on ex vivo assessment of YAC-1 and MADB106 target-line lysis. Additionally, in vitro studies assessed the kinetics of the impact of epinephrine, CORT, and PGE(2) on NKCC. The results indicated that suppression of NKCC by epinephrine and PGE(2) are short lasting, and cannot be evident when these compounds are removed from the in vitro assay milieu, or in the context of ex vivo assessment of NKCC. In contrast, the effects of CORT are long-lasting and are reflected in both conditions even after its removal. Marginating-pulmonary NKCC was less susceptible to suppression than circulating NKCC, when tested against the xenogeneic YAC-1 target line, but not against the syngeneic MADB106 line, which seems to involve different cytotoxicity mechanisms. Overall, these findings indicate that elevated systemic PG levels can directly suppress NKCC in vivo, but following laparotomy adrenal hormones mediate most of the effects of endogenously-released PGs. Additionally, the ex vivo approach seems limited in reflecting the short-lasting NK-suppressive effects of catecholamines and PGs.

A boswellic acid-containing extract attenuates hepatic granuloma in C57BL/6 mice infected with Schistosoma japonicum

Granuloma formation has been shown to be induced and elicited by schistosome egg antigens, and it finally develops into fibrosis in intestine and the liver. Hepatic fibrosis is the main cause of increased morbidity and mortality in humans infected with schistosomes. Boswellic acid (BA)-containing extracts such as extracts of the oleogum resin from Boswellia serrata (BSE) have anti-inflammatory and immunomodulatory activity. However, little is known about the role of such extracts in schistosome egg-induced granulomatous inflammation. In order to investigate the effect of a watersoluble cyclodextrin complex preparation of BSE (BSE-CD) on Schistosoma japonicum (S. japonicum) egg-induced liver granuloma, mice infected with S. japonicum cercariae were injected with BSE-CD during egg granuloma formation. The data showed that BSE-CD significantly reduced the size of liver granuloma and levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST); however, BSE-CD treatment had no effect on worm load and egg burden. The data also showed that BSE-CD significantly decreased the expression of leukotriene B(4) (LTB(4)) and prostaglandin E(2) (PGE(2)), as well as the expression of matrix metallopeptidase 9 (MMP-9) in liver both on the mRNA and protein level. Thus, BSE-CD can significantly attenuate S. japonicum egg-induced hepatic granuloma, which may be partly dependent on the downregulation of some biochemical mediators.

[Perioperative tumour dissemination. 2. Effects of anaesthesia and analgesia]

There has been growing concern over the last few years on the effect that the anaesthetic drugs used during oncological surgery could have on long-term tumour progression. In laboratory studies, it has been observed how some substances used during the anaesthetic procedure influence tumour immunosurveillance, cell proliferation or tumour angiogenesis processes. The possible clinical relevance of the anaesthetic technique used as regards long-term tumour progression and survival is still to be determined. However, based on retrospective studies, it appears that those anaesthetic techniques combined with the use of regional anaesthesia and analgesia may be beneficial compared to those that are maintained on the use of opioids. Further research should help to clarify the long-term clinical relevance of the anaesthetic process during oncological surgery.

Do intraoperative analgesics influence breast cancer recurrence after mastectomy? A retrospective analysis

BACKGROUND

Whether intraoperative analgesics have an impact on postoperative cancer recurrence is unknown. Some investigations suggest that the opioids could favor relapse and that regional analgesia and nonsteroidal antiinflammatory drugs could improve cancer prognosis. We retrospectively reviewed our series of breast cancer surgery patients.

METHODS

This retrospective study included 327 consecutive women who underwent mastectomy with axillary dissection for breast cancer. The main objective was to compare the incidence of cancer recurrence among patients who received different analgesics during surgery.

RESULTS

Perioperative characteristics, cancer prognostic factors, and the length of surgery were comparable regardless of the analgesics administered. Univariate and multivariate analyses showed a lower cancer recurrence rate when ketorolac was given before surgery (P = 0.019). Other analgesics (sufentanil, ketamine, and clonidine) were not associated with a significant reduction in cancer recurrence rates in our series.

CONCLUSION

This retrospective analysis suggests that intraoperative administration of ketorolac decreases the risk of breast cancer relapse compared with other analgesícs.

[Could anaesthesia, analgesia and sympathetic modulation affect neoplasic recurrence after surgery? A systematic review centred over the modulation of natural killer cells activity]

OBJECTIVE

The Natural Killer cells (NK) are an important part of non-specific cellular-mediated and antitumoral immunity. The goal of this review is to recapitulate data published over NK activity during the perioperative period and the influence of anaesthesia, analgesia and modulation of sympathetic system.

DATA SOURCES

Pubmed/Medline database.

STUDY SELECTION AND DATA EXTRACTION

Keywords-based selection, without limit of date: fundamental studies, randomized controlled trials and non-randomized comparative studies.

DATA SYNTHESIS

In human as in animal studies, an important correlation exists between NK activity and prognosis linked to the development of metastasis. The great depression of this cytotoxicity during the perioperative period could be able to compromise host defenses. The influence of anaesthetics and analgesics is important. The effects of the opioids, the agonists and the antagonists of the sympathetic nervous system, the prostaglandins, the NSAIDs, the ketamine, the hypnotics and the locoregional anaesthesia are systematically reviewed. The limits of experimental model presented are covered.

CONCLUSION

The effects of anaesthetic/analgesic drugs and techniques, the consequences of sympathomodulation on NK activity are numerous and sometimes opposite. It is important for the anaesthesiologist to keep in mind that the long term consequences of his techniques on the patients' outcome must be clarified.

Progression of pancreatic adenocarcinoma is significantly impeded with a combination of vaccine and COX-2 inhibition

With a 5-year survival rate of <5%, pancreatic cancer is one of the most rapidly fatal malignancies. Current protocols for the treatment of pancreas cancer are not as effective as we desire. In this study, we show that a novel Mucin-1 (MUC1)-based vaccine in combination with a cyclooxygenase-2 inhibitor (celecoxib), and low-dose chemotherapy (gemcitabine) was effective in preventing the progression of preneoplastic intraepithelial lesions to invasive pancreatic ductal adenocarcinomas. The study was conducted in an appropriate triple transgenic model of spontaneous pancreatic cancer induced by the KRAS(G12D) mutation and that expresses human MUC1 as a self molecule. The combination treatment elicited robust antitumor cellular and humoral immune responses and was associated with increased apoptosis in the tumor. The mechanism for the increased immune response was attributed to the down-regulation of circulating prostaglandin E(2) and indoleamine 2, 3,-dioxygenase enzymatic activity, as well as decreased levels of T regulatory and myeloid suppressor cells within the tumor microenvironment. The preclinical data provide the rationale to design clinical trials with a combination of MUC1-based vaccine, celecoxib, and gemcitabine for the treatment of pancreatic cancer.

MUC1 enhances tumor progression and contributes toward immunosuppression in a mouse model of spontaneous pancreatic adenocarcinoma

MUC1, a membrane tethered mucin glycoprotein, is overexpressed and aberrantly glycosylated in >80% of human ductal pancreatic adenocarcinoma. However, the role of MUC1 in pancreatic cancer has been elusive, partly due to the lack of an appropriate model. We report the characterization of a novel mouse model that expresses human MUC1 as a self molecule (PDA.MUC1 mice). Pancreatic tumors arise in an appropriate MUC1-tolerant background within an immune-competent host. Significant enhancement in the development of pancreatic intraepithelial preneoplastic lesions and progression to adenocarcinoma is observed in PDA.MUC1 mice, possibly due to increased proliferation. Tumors from PDA.MUC1 mice express higher levels of cyclooxygenase-2 and IDO compared with PDA mice lacking MUC1, especially during early stages of tumor development. The increased proinflammatory milieu correlates with an increased percentage of regulatory T cells and myeloid suppressor cells in the pancreatic tumor and tumor draining lymph nodes. Data shows that during pancreatic cancer progression, MUC1-mediated mechanisms enhance the onset and progression of the disease, which in turn regulate the immune responses. Thus, the mouse model is ideally suited for testing novel chemopreventive and therapeutic strategies against pancreatic cancer.

Lipids changes in liver cancer

Liver is one of the most important organs in energy metabolism. Most plasma apolipoproteins and endogenous lipids and lipoproteins are synthesized in the liver. It depends on the integrity of liver cellular function, which ensures homeostasis of lipid and lipoprotein metabolism. When liver cancer occurs, these processes are impaired and the plasma lipid and lipoprotein patterns may be changed. Liver cancer is the fifth common malignant tumor worldwide, and is closely related to the infections of hepatitis B virus (HBV) and hepatitis C virus (HCV). HBV and HCV infections are quite common in China and other Southeast Asian countries. In addition, liver cancer is often followed by a procession of chronic hepatitis or cirrhosis, so that hepatic function is damaged obviously on these bases, which may significantly influence lipid and lipoprotein metabolism in vivo. In this review we summarize the clinical significance of lipid and lipoprotein metabolism under liver cancer.

Cyclooxygenase-2 inhibitor enhances the efficacy of a breast cancer vaccine: role of IDO

We report that administration of celecoxib, a specific cyclooxygenase-2 (COX-2) inhibitor, in combination with a dendritic cell-based cancer vaccine significantly augments vaccine efficacy in reducing primary tumor burden, preventing metastasis, and increasing survival. This combination treatment was tested in MMTV-PyV MT mice that develop spontaneous mammary gland tumors with metastasis to the lungs and bone marrow. Improved vaccine potency was associated with an increase in tumor-specific CTLs. Enhanced CTL activity was attributed to a significant decrease in levels of tumor-associated IDO, a negative regulator of T cell activity. We present data suggesting that inhibiting COX-2 activity in vivo regulates IDO expression within the tumor microenvironment; this is further corroborated in the MDA-MB-231 human breast cancer cell line. Thus, a novel mechanism of COX-2-induced immunosuppression via regulation of IDO has emerged that may have implications in designing future cancer vaccines.

Surgery Today The Japanese Journal of Surgery

This month's selection from the October to December 1995 issues of Surgery Today (The Japanese Journal of Surgery) is written by Professor K. Sugimachi. A digest of the BJS for the same period, written by Mr Colin Johnson, appears in the Japanese journal.

Effect of combined cyclooxygenase-2 and matrix metalloproteinase inhibition on human sarcoma xenografts

PURPOSE

Sarcomas express cyclooxygenase (COX)-2, an inducible enzyme with known tumor-promoting activity. COX-2 inhibition is efficacious against many cancer types but has not been tested for human sarcomas. Matrix metalloproteinase (MMP) inhibitors also possess antiproliferative activity. Because MMP inhibitor therapy induces COX-2 expression, the authors hypothesized that the combination of COX-2 and MMP inhibitors results in a synergistic antitumor effect.

METHODS

Human osteosarcoma or rhabdomyosarcoma cells were injected into athymic mice. Tumor development and growth were measured following treatment with a COX-2 inhibitor (celecoxib), an MMP inhibitor (doxycycline), or both. The tumors were analyzed for necrosis, apoptosis, cyclooxygenase activity (PGE2 production), and MMP-2 levels.

RESULTS

When treatment was started prior to tumor cell implantation, doxycycline inhibited osteosarcoma tumor growth alone and in combination with celecoxib (30% and 33% reduction, respectively). An effect on osteosarcoma tumor implantation rates was noted in mice receiving doxycycline alone and in combination with celecoxib (12.5% and 6.25% reduction, respectively). Established osteosarcoma and rhabdomyosarcoma tumors were inhibited only by combination therapy (36% and 55%, respectively). A higher proportion of osteosarcoma tumors in the combination therapy group had more than 50% necrosis (3/7) when compared with control tumors (0/8). Antitumor effects did not correlate with PGE2 levels, suggesting the observed interaction with doxycycline was due to previously described non-enzymatic effects of celecoxib.

CONCLUSIONS

The authors' preclinical data suggest that the combination of inexpensive, nontoxic, oral COX-2 and MMP inhibitors may be useful for the treatment of some types of solid tumors.

Prostaglandin e(2) suppresses NK activity in vivo and promotes postoperative tumor metastasis in rats

BACKGROUND

Prostaglandins (PGs) were shown in vitro to suppress several functions of cellular immunity. It is unclear, however, whether physiological levels of PGs can suppress cellular immunity in vivo and whether such suppression would compromise postoperative host resistance to metastasis.

METHODS

Fischer 344 rats were administered PGE(2) in doses (18 to 300 micro g/kg subcutaneously) that increased the serum levels approximately 2- to 4-fold. We then assessed the number and activity of circulating natural killer (NK) cells, as well as rats' resistance to experimental metastasis of a syngeneic NK-sensitive tumor (MADB106). To study whether endogenously released PGs after surgery compromise these indices, we tested whether laparotomy adversely affects them and whether a cyclooxygenase-synthesis inhibitor, indomethacin (4 mg/kg), attenuates these effects.

RESULTS

PGE(2) dose-dependently suppressed NK activity per NK cell and dose-dependently increased 4- and 24-hour MADB106 lung tumor retention (LTR); 240 micro g/kg of PGE(2) quadrupled the number of lung metastases counted 3 weeks later. Selective depletion of NK cells abrogated the promotion of LTR by PGE(2). Surgery significantly suppressed NK activity and increased MADB106 LTR, and indomethacin halved these effects without affecting nonoperated rats.

CONCLUSIONS

PGE(2) is a potent in vivo suppressor of NK activity, and its postoperative release may promote tumor recurrence.

Cyclooxygenases and lipoxygenases as potential targets for treatment of pancreatic cancer

Pancreatic adenocarcinoma is characterized by poor prognosis, late diagnosis and lack of response to conventional therapies. The incidence of this disease shows no sign of declining in the Western world. Thus, new targets need to be identified for pancreatic cancer treatment. In particular, new chemotherapeutic agents would be extremely beneficial for control of unresectable cancer and metastatic lesions as well as for prevention of this deadly disease. Mounting evidence suggests that both lipoxygenases (LOXs) and cyclooxygenases (COXs), the key enzymes for arachidonic acid metabolism, have a profound influence on the development and progression of several human cancers. Recent evidence suggests that both COX and LOX pathways are important in pancreatic cancer. Results from immunocytochemical, RT-PCR, and Western blotting studies have shown that COX, specifically COX-2, is upregulated in human pancreatic cancer cell lines as well as human pancreatic cancer tissues compared with normal ductal cells and normal pancreas specimens. Agents that block COX enzymes significantly inhibit pancreatic cancer growth both in vitro and in vivo, in parallel with induction of apoptosis. Expression of both 5-LOX and 12-LOX is also seen in pancreatic cancer, although compared to the expression of COX this has not been extensively investigated. Chemical inhibitors or antisense oligonucleotides that block either 5-LOX or 12-LOX cause marked inhibition of pancreatic cancer cell proliferation. On the other hand, LOX metabolites stimulate growth of the tumor cells and reverse LOX-inhibitor-induced growth inhibition, suggesting the specific role of LOX in regulating pancreatic cancer cell proliferation. Although questions still need to be answered, such as the underlying mechanisms for COX and LOX-induced growth inhibition, both COX and LOX pathways are potential targets for pancreatic cancer treatment and chemoprevention. COX and LOX enzyme inhibitors are available and have been shown to be relatively safe in the treatment of other diseases.

Indomethacin attenuates the immunosuppressive and tumor-promoting effects of surgery

We have previously shown in rats that both intrathecal and systemic analgesia regimens attenuate surgery-induced increases in tumor susceptibility. The current study used indomethacin to assess the role of prostaglandins and inflammation-associated pain in mediating the deleterious effects of surgery on immunity and tumor susceptibility. Male and female Fischer 344 rats were anesthetized with halothane and were either subjected or not to experimental laparotomy, followed by the administration of indomethacin or vehicle. Tumor susceptibility was assessed by the lung retention assay using the syngeneic MADB106 mammary adenocarcinoma cell line, a natural killer (NK)-sensitive tumor that colonizes only in the lungs. Surgery resulted in a 2- to 3.5-fold increase in lung tumor retention, and indomethacin administration significantly reduced this effect in both sexes without affecting unoperated animals. Indomethacin also attenuated the reductions in rearing behavior evident after surgery, suggesting that it relieved abdominal discomfort. Surgery increased interleukin-6 levels and suppressed NK activity per milliliter blood. Indomethacin restored NK activity in both male and female rats but attenuated surgery-induced interleukin-6 increases only in the male rats. These findings further support our previous work implicating pain in mediating the tumor-enhancing effects of surgery and implicate prostaglandins in mediating this effect. If similar relationships occur in humans, controlling postoperative pain and inflammation must become a priority in the management of cancer patients undergoing surgery.

Opposing effects of prostaglandin E(2)and F(2 alpha) on rat liver-associated natural killer cell activity in vitro

Strain differences in cancer incidence are proposed to be due partly to differences in immune function. As potential cancer-associated immunological regulators, the concentrations of hepatic prostaglandins E(2)(PGE(2 alpha)and F(2 alpha)(PGF(2 alpha)) were compared in 9-week-old male and female F344/N and Sprague-Dawley (SD) rats. There were no strain or gender differences in the concentrations of hepatic PGE(2). No strain difference was found in the concentration of hepatic PGF(2 alpha), but the hepatic PGF(2 alpha)concentration in female rats was two-fold that of the male rat (130 vs 60 ng/g). PGE(2)significantly inhibited hepatic natural-killer cell (NK) activity in vitro compared with untreated cells from both genders and strains (P<0.05), 25 ng PGE(2)/ml inhibited NK activity significantly more than did 10 ng PGE(2)/ml (P<0.05). In contrast, 50 ng PGF(2 alpha)/ml and 100 ng PGF(2 alpha)/ml significantly stimulated hepatic NK activity compared with untreated hepatic cells from both F344/N and SD rats. This study suggests that prostaglandins may have a negligible net effect on NK activity associated with rat liver, and may be unlikely to mediate cancer-related immune function.

Dietary linoleic acid, immune inhibition and disease

Review of the evidence available in published literature supports a radical change in viewpoint with respect to disease in countries where maize is the predominant dietary component. In these countries, the pattern of disease is largely determined by a change in immune profile caused by metabolites of dietary linoleic acid. High intake of linoleic acid in a diet deficient in other polyunsaturated fatty acids and in riboflavin results in high tissue production of prostaglandin E2, which in turn causes inhibition of the proliferation and cytokine production of Th1 cells, mediators of cellular immunity. Tuberculosis, measles, hepatoma, secondary infection in HIV and kwashiorkor are all favoured by this reduction in cellular immunity. Diet-associated inhibition of the Th1 subset is a major contributor to the high prevalence of these diseases found in areas of sub-Saharan Africa where maize is the staple.

Interleukin-2-activated natural killer cells can induce both apoptosis and necrosis in rat hepatocytes

Natural killer (NK) cells play a crucial role in the elimination of virus-infected or transformed cells in the liver. In this article, we describe the mechanism by which liver cells are killed by NK cells. Interleukin-2-activated natural killer (A-NK) cells from the rat induced apoptotic cell death in 30% of freshly isolated rat hepatocytes within 60 minutes. Recognition by the A-NK cells of the hepatocytes as nonself was established by masking the major histocompatibility complex (MHC) class I molecules on the hepatocytes with the OX18 antibody. During the killing process, a decrease of the mitochondrial membrane potential (MMP), formation of blebs, phosphatidyl serine (PS) externalization, chromatin condensation, and nuclear fragmentation were observed. The hepatocytes became apoptotic before permeabilization of the plasma membrane occurred, suggesting that the observed cytolysis was caused by secondary necrosis. The apoptotic process was completely abolished by the caspase inhibitors, Z-Val-Ala-DL-Asp fluormethylketone (zVAD-fmk) and Ac-Asp-Glu-Val-aldehyde (DEVD-cho). However, under these conditions, A-NK cells killed a smaller fraction of the hepatocytes by (primary) necrosis. These results indicate that apoptosis is the major cytotoxic process induced by A-NK cells in hepatocytes. If apoptosis is prevented, a more limited necrotic effect is induced. Therefore, this study shows that NK cells are fully equipped to induce both apoptosis and necrosis in hepatocytes, but appear to prefer the apoptotic route.

Hepatic immunopotentiation by galactose-entrapped liposomal IL-2 compound in the treatment of liver metastases

To activate hepatic sinusoidal lymphocytes (HSL) and increase the local antitumor activity in the liver, we developed a liver-targeted interleukin-2 (IL-2) compound using a galactose residue-entrapped liposome. We prepared various kinds of IL-2-containing liposomes made by the hydration of powdered dimyristoyl-phosphatidylcholine with aqueous recombinant IL-2 followed by the combination with galactose residues to facilitate the selective uptake by liver parenchymal cells bearing galactose receptors. The IL-2 liposomes were given to C3H/He mice followed by the determination of: (1) organ distribution by 125I-labeled IL-2, (2) antitumor activity of hepatic sinusoidal lymphocytes by 51Cr-release assay, and (3) in vivo antitumor efficacy by the measurement of hepatic metastases. When galactose-entrapped IL-2 liposomes (Gallip-IL-2) were administered, a significantly greater hepatic accumulation of IL-2 was seen for up to 2 weeks compared to IL-2 liposomes or free IL-2. According to these results, the antitumor activity of HSL was significantly augmented. Moreover, when mice with hepatic micrometastases were treated with Gal-lip-IL-2, the area of hepatic metastases was significantly reduced. These findings thus indicate that Gal-lip-IL-2 may enhance the therapeutic efficacy of IL-2 against hepatic metastases and thereby facilitate a more practical daily dosing regimen.

In vitro effects of prostaglandin E2 or indomethacin on the proliferation of lymphokine-activated killer cells and their cytotoxicity against bladder tumor cells in patients with bladder cancer

PURPOSE

To investigate the combined effects of interleukin-2 (IL-2) with either prostaglandin E2 (PGE2) or indomethacin (IM) on the proliferation and cytolysis of bladder tumor cells by lymphokine-activated killer (LAK) cells in patients with bladder cancer.

METHODS

LAK cell proliferation was assayed in the presence of various concentrations of either PGE2 or IM by cell counting. Bladder cancer cell lines BIU-87, EJ and bladder tumor cells (BTC) from the patients were cultured as target cells, and the cytotoxicity of LAK cells was determined by 3-(4.5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. In addition, PGE2 in samples of conditioned medium from bladder cancer cells or peripheral blood mononuclear cells (PBMC) as well as plasma from 21 patients with bladder cancer and 20 healthy donors were determined by radioimmunoassay (RIA).

RESULTS

The proliferation of LAK cells induced by IL-2 was inhibited by PGE2 (0.05 to 5 ng/mL) in concentration-dependent manner. The enhanced growth of LAK cells was observed at certain concentrations of IM (100-400 ng/mL) from 48 to 96 h. Pretreatment of LAK cells with IM (200 ng/mL) significantly enhanced cytotoxicity against BIU-87, EJ cells, or BTC. More PGE2 was present in conditioned medium from BIU-87 cells than in the conditioned medium from PBMC.

CONCLUSIONS

These studies indicate that LAK cell proliferation induced by IL-2 in patients with bladder cancer is inhibited by PGE2 produced by PBMC and bladder cancer cells. This inhibition can be overcome by IM, which may be of use in immunotherapy of bladder cancer.