Mechanisms of organ selective tumour growth by bloodborne cancer cells

Incomplete bowel obstruction caused by sigmoid colon cancer in an inguinal hernia: a case report

BACKGROUND

Most colon cancers that develop in the intestinal tract within the inguinal hernia sac are identified by incarceration. However, treatment methods for these cases vary depending on the pathology. Cases showing perforation or abscess formation require emergency surgery for infection control, while cases with no infection generally involve oncological resection, with laparoscopic surgery also being an option. We encountered a case of Incomplete bowel obstruction secondary to sigmoid colon cancer within the hernial sac. We report the process leading to the selection of the treatment method and the surgical technique, along with a review of the literature.

CASE PRESENTATION

A 79-year-old man presented to our hospital complaining of a left inguinal bulge (hernia) and pain in the same area. The patient had the hernia for more than 20 years. Using computed tomography, we diagnosed an incomplete bowel obstruction caused by a tumor of the intestinal tract within the hernial sac. Since imaging examination showed no signs of strangulation or perforation, we decided to perform elective surgery after a definitive diagnosis. After colonoscopy, we diagnosed sigmoid colon cancer with extra-serosal invasion; however, we could not insert a colorectal tube. Although we proposed sigmoid resection and temporary ileostomy, we chose the open Hartmann procedure because the patient wanted a single surgery. For the hernia, we simultaneously used the Iliopubic Tract Repair method, which does not require a mesh. Eight months after the surgery, no recurrence of cancer or hernia was observed.

CONCLUSIONS

We report a case of advanced sigmoid colon cancer with a long-standing inguinal hernia that later became incomplete bowel obstruction. Although previous studies have used various approaches among the available surgical methods for cancer within the hernial sac, such as inguinal incision, laparotomy, and laparoscopic surgery, most hernias are repaired during the initial surgery using a non-mesh method. For patients with inguinal hernias that have become difficult to treat, the complications of malignancy should be taken into consideration and the treatment option should be chosen according to the pathophysiology.

Metastasis of renal cell carcinoma around suture anchor implants

We present an unusual case of bone metastases from renal cell carcinoma around orthopedic implants in a 78-year-old female with osteolytic, expansile, highly vascularized, malignant infiltration around suture anchors in the proximal humerus. The patient had undergone arthroscopic rotator cuff repair using suture anchor implants 6 years previously. After diagnosis of bone metastasis, she was successfully treated with metastasectomy and internal fixation using a plate and screws, with cement augmentation. This report is the first to document metastases around a suture anchor in a bone and suggests the vulnerability of suture anchor implants to tumor metastasis.

Patient-derived xenograft (PDX) models in basic and translational breast cancer research

Patient-derived xenograft (PDX) models of a growing spectrum of cancers are rapidly supplanting long-established traditional cell lines as preferred models for conducting basic and translational preclinical research. In breast cancer, to complement the now curated collection of approximately 45 long-established human breast cancer cell lines, a newly formed consortium of academic laboratories, currently from Europe, Australia, and North America, herein summarizes data on over 500 stably transplantable PDX models representing all three clinical subtypes of breast cancer (ER+, HER2+, and "Triple-negative" (TNBC)). Many of these models are well-characterized with respect to genomic, transcriptomic, and proteomic features, metastatic behavior, and treatment response to a variety of standard-of-care and experimental therapeutics. These stably transplantable PDX lines are generally available for dissemination to laboratories conducting translational research, and contact information for each collection is provided. This review summarizes current experiences related to PDX generation across participating groups, efforts to develop data standards for annotation and dissemination of patient clinical information that does not compromise patient privacy, efforts to develop complementary data standards for annotation of PDX characteristics and biology, and progress toward "credentialing" of PDX models as surrogates to represent individual patients for use in preclinical and co-clinical translational research. In addition, this review highlights important unresolved questions, as well as current limitations, that have hampered more efficient generation of PDX lines and more rapid adoption of PDX use in translational breast cancer research.

Cellular and molecular processes in ovarian cancer metastasis. A Review in the Theme: Cell and Molecular Processes in Cancer Metastasis

Ovarian cancer is the most lethal gynecological malignancy. It is usually diagnosed at a late stage, with a 5-yr survival rate of <30%. The majority of ovarian cancer cases are diagnosed after tumors have widely spread within the peritoneal cavity, limiting the effectiveness of debulking surgery and chemotherapy. Owing to a substantially lower survival rate at late stages of disease than at earlier stages, the major cause of ovarian cancer deaths is believed to be therapy-resistant metastasis. Although metastasis plays a crucial role in promoting ovarian tumor progression and decreasing patient survival rates, the underlying mechanisms of ovarian cancer spread have yet to be thoroughly explored. For many years, researchers have believed that ovarian cancer metastasizes via a passive mechanism by which ovarian cancer cells are shed from the primary tumor and carried by the physiological movement of peritoneal fluid to the peritoneum and omentum. However, the recent discovery of hematogenous metastasis of ovarian cancer to the omentum via circulating tumor cells instigated rethinking of the mode of ovarian cancer metastasis and the importance of the "seed-and-soil" hypothesis for ovarian cancer metastasis. In this review we discuss the possible mechanisms by which ovarian cancer cells metastasize from the primary tumor to the omentum, the cross-talk signaling events between ovarian cancer cells and various stromal cells that play crucial roles in ovarian cancer metastasis, and the possible clinical implications of these findings in the management of this deadly, highly metastatic disease.

The role of hepatic ischemia-reperfusion injury and liver parenchymal quality on cancer recurrence

Hepatic ischemia/reperfusion (I/R) injury is a common clinical challenge. Despite accumulating evidence regarding its mechanisms and potential therapeutic approaches, hepatic I/R is still a leading cause of organ dysfunction, morbidity, and resource utilization, especially in those patients with underlying parenchymal abnormalities. In the oncological setting, there are growing concerns regarding the deleterious impact of I/R injury on the risk of post-surgical tumor recurrence. This review aims at giving the last updates regarding the role of hepatic I/R and liver parenchymal quality injury in the setting of oncological liver surgery, using a "bench-to-bedside" approach. Relevant medical literature was identified by searching PubMed and hand scanning of the reference lists of articles considered for inclusion. Numerous preclinical models have depicted the impact of I/R injury and hepatic parenchymal quality (steatosis, age) on increased cancer growth in the injured liver. Putative pathophysiological mechanisms linking I/R injury and liver cancer recurrence include an increased implantation of circulating cancer cells in the ischemic liver and the upregulation of proliferation and angiogenic factors following the ischemic insult. Although limited, there is growing clinical evidence that I/R injury and liver quality are associated with the risk of post-surgical cancer recurrence. In conclusion, on top of its harmful early impact on organ function, I/R injury is linked to increased tumor growth. Therapeutic strategies tackling I/R injury could not only improve post-surgical organ function, but also allow a reduction in the risk of cancer recurrence.

Lung cancer with gastrointestinal metastasis - review of theories of metastasis with three rare case descriptions

Approximately 1 in 14 men and women during their lifetime will be diagnosed with lung cancer, which is the leading cause of cancer-related mortality in the world. As of January 1, 2008, there were about 373,500 men and women living with lung cancer in the United States. Fewer than 60,000 of these are estimated to be alive by January 2013, reflecting a poor overall 5-year relative survival rate of under 16 %. With metastatic cancer, the overall 5-year survival is meager 4 %. On the other hand, the overall five-year survival is over 50 % when the cancer is still in the localized stage. However, unfortunately, more than half of cases of lung cancer are diagnosed at an advanced stage Howlader et al. (2010). Cancer metastasis, the single most critical prognostic factor, is still poorly understood and a highly complex phenomenon. The most common sites of lung cancer metastasis are the lymph nodes, liver, adrenals, brain and bones. The gastrointestinal (GI) tract is an exceptionally rare site of metastasis; with only a handful of cases reported in the literature Centeno et al. (Lung Cancer, 18: 101-105, 1997); Hirasaki et al. (World J Gastroenterol, 14: 5481-5483, 2008); Carr and Boulos (Br J Surg, 83: 647, 1996); Otera et al. (Eur Respir Rev, 19: 248-252, 2010); Antler et al. (Cancer, 49: 170-172, 1982); Fujiwara et al. (Gen Thorac Cardiovasc Surg, 59: 748-752, 2011); Stinchcombe et al. (J Clin Oncol, 24: 4939-4940, 2006); John et al. (J Postgrad Med, 48: 199-200, 2002); Carroll and Rajesh (Eur J Cardiothorac Surg, 19: 719-720, 2001); Brown et al. (Dis Colon Rectum, 23: 343-345, 1980). We report three cases of non-small cell (squamous cell) lung cancer with GI tract metastasis-two in the colon and one in the jejunum. Then we present a review of literature exploring various theories of metastasis, as an attempt to understand the reason of preferential tumor metastasis.

Insulin-like growth factor-I regulates the liver microenvironment in obese mice and promotes liver metastasis

Among the mechanisms implicated in the tumor-promoting effects of obesity, signaling by insulin-like growth factor-I (IGF-I) and insulin has received considerable attention. However, the emerging realization that obesity is associated with chronic inflammation has prompted other consideration of how the IGF-I axis may participate in cancer progression. In the present study, we used two mouse models of chronic (LID) and inducible (iLID) igf-1 gene deficiency in the liver to investigate the role of IGF-I in regulating the host microenvironment and colorectal carcinoma growth and metastasis in obese mice. Obese mice had a heightened inflammatory response in the liver, which was abolished in mice with chronic IGF-I deficiency (LID). In control animals changes to the hepatic microenvironment associated with obesity sustained the presence of tumor cells in the liver and increased the incidence of hepatic metastases after intrasplenic/portal inoculation of colon carcinoma cells. These changes did not occur in LID mice with chronic IGF-1 deficiency. In contrast, these changes occurred in iLID mice with acute IGF-1 deficiency, in the same manner as the control animals, revealing a fundamental difference in the nature of the requirement for IGF-1 on tumor growth and metastasis. In the setting of obesity, our findings imply that IGF-1 is critical to activate and sustain an inflammatory response in the liver that is needed for hepatic metastasis, not only through direct, paracrine effect on tumor cell growth, but also through indirect effects involving the tumor microenvironment.

A small mammal model of tumour implantation, dissemination and growth factor expression after partial hepatectomy

BACKGROUND

Surgical resection remains the most effective therapy for metastatic colorectal cancer confined to the liver, although the extrahepatic recurrence rate is high.

AIM OF THE STUDY

To develop a mammal model in order to investigate by which mechanisms liver surgery affects distant tumour recurrence.

METHODS

In this animal study the effect of partial hepatectomy (phX) on the development of tumour noduli in the lungs was evaluated. CC531 rat colon carcinoma cells were inoculated i.v. 24h before, during or 24h after surgery. Rat serum was obtained at different time-points after phX and added to in vitro CC531 cell cultures. Finally, phX was compared with an ileum resection (ilX).

RESULTS

phX leads to increased tumour noduli in the lungs, compared to Sham operation (p=0.002), but only when performed directly before the injection of tumour cells and not when performed 24h before or after the inoculation. Comparable results were obtained for ilX. No growth stimulation of tumour cells after incubation with rat serum, obtained at different time-points after phX, could be detected in vitro.

CONCLUSION

Not only phX, but also surgery, in general promotes distant tumour recurrence exerting the effect during the early phase of tumour cell adhesion and not during tumour outgrowth.

Breast metastasis around dental implants: a case report

BACKGROUND

Metastases to the oral cavity and to the jaws are rare; hence, the clinical manifestations of the oral metastasis lesion could frequently be simulating general pathologic entities, making the diagnosis a challenging process to the dental team. Local factors, such as trauma, have been observed to facilitate the growth of blood-borne tumors. To this end, surgical procedures such as fixture placement might cause cancer cells to spread.

PURPOSE

Careful clinical examination is a valuable help in diagnosing oral lesions, which can improve the quality of life of patients and reduce the risks of oral complications.

MATERIALS AND METHODS

A female patient was referred to the clinic with symptoms of irritation, swelling, and pain associated with implants in the mandible and the maxilla.

RESULTS

Clinical examination, x-ray, and histopathology revealed that the patients suffered from a metastatic lesion, primary tumor being an adenocarcinoma of the breast diagnosed at the same time.

CONCLUSION

Optimal clinical examination in conjunction with radiography and histopathology is a necessity in order to discover malignant lesions in time. Routine dental check-ups must comprise more thorough soft-tissue examination.

Comparing and combining light dose fractionation and iron chelation to enhance experimental photodynamic therapy with aminolevulinic acid

BACKGROUND AND OBJECTIVES

Enhancement of photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA) has been demonstrated experimentally using light dose fractionation or CP94 iron chelation. This study extends this research.

STUDY DESIGN/MATERIALS AND METHODS

In normal rat colon, CP94 administration and light dose fractionation were independently and concurrently employed to enhance ALA-PDT. In colonic rat tumors, the most successful enhancement regimes were employed separately.

RESULTS

Independent use of light dose fractionation and iron chelation produced similar results in normal colon (2.4- and 2.9-fold more necrosis than controls, respectively). Using both techniques simultaneously produced fivefold enhancement. In the colonic tumors, light dose fractionation and iron chelation (using different parameters) produced two and five times the volume of necrosis, respectively.

CONCLUSIONS

Both techniques significantly enhanced ALA-PDT in the normal and neoplastic tissues investigated and produced similar levels of enhancement when comparable parameters were employed. Concurrent use of light dose fractionation and iron chelation in normal colon produced considerably more enhancement than either technique could achieve independently.

Photodynamic therapy with WST09 (Tookad): quantitative studies in normal colon and transplanted tumours

Photodynamic therapy (PDT) is attracting increasing interest for the safe destruction of localised tumours in a range of organs. However, most photosensitising drugs require a delay of hours to days between drug administration and light activation with skin photosensitivity that may last for weeks. WST09 (Tookad) is a new faster acting photosensitiser that clears within a few hours. In normal rat colon, after sensitisation with an intravenous bolus of WST09, light was delivered to a single point on the mucosa and the extent of PDT necrosis measured 3 days later. The lesion diameter was greatest with the highest dose of drug and light and the shortest drug light interval (DLI), falling rapidly with a DLI more than 5 min. In tumours transplanted subcutaneously or into the colon, the extent of necrosis only started falling with a DLI greater than 15 min, suggesting a possible window for tumour selectivity. Histological changes 3 days after PDT were essentially the same as those seen with longer acting photosensitisers. The lesion dimensions were comparable to the largest ones seen with other photosensitisers under similar experimental conditions. We conclude that WST09 is a powerful photosensitiser that produces PDT effects similar to those seen with longer acting drugs, but with the major advantages of a short DLI and rapid clearance.

Diethylstilbestrol-induced prolactinoma: dose-related tumor growth and effect of catecholaminergic cells on prolactin tumor cells

BACKGROUND

Prolactinoma is a pituitary adenoma originating from prolactin-secreting epithelial cells of the adenohypophysis. Unfortunately, there appears to be a relatively high recurrence rate despite all pharmacological, radiological, and surgical therapeutic interventions. The aim of the present study was to evaluate the extent of involvement of the dopaminergic dysregulation hypothesis of prolactinomas. We transplanted, in rats, DES-induced prolactinoma cells into the adrenal medulla or under the renal capsule, two tissues rich and poor in catecholaminergic innervation, respectively.

METHODS

Prolactinoma was dose-dependently induced in ovariectomized female rats implanted with 10 and 20 mg DES, and tumor cells taken from prolactinoma induced by 20 mg DES were either transplanted under the renal capsule or into the adrenal medulla.

RESULTS

Although the adrenal medulla, with its high dopamine content to inhibit prolactin secretion, was devoid of any tumoral development, a significant tumoral development was evident under the renal capsule, seemingly because of no inhibitory control over prolactin secretion coexisting with the dopamine deficiency of the tissue. Results are discussed for an alternatively possible regression and prevention of any relapse of prolactinoma, most possibly occurring because of tuberoinfundibular dopamine deficiency, by the implantation of another dopamine-rich tissue beside the tumoral mass.

CONCLUSION

Regression and prevention of any relapse of a tumoral outgrowth, most possibly occurring because of tuberoinfundibular dopamine deficiency, can well be alternatively achieved by the implantation of another dopamine-rich tissue beside the tumoral mass prolactinoma.

Glucocorticoid administration in antiemetic therapy: is it safe?

BACKGROUND

Although glucocorticoids are often used in cancer therapy, in particular to enhance the effectiveness of antiemetic therapy, they have been associated with impaired tumor apoptosis and an increased frequency of metastases in some reports. The current study aimed to determine whether glucocorticoid treatment had an adverse effect on outcomes in patients with ovarian carcinoma.

METHODS

Records of patients with ovarian carcinoma who were scheduled to receive at least six courses of systemic chemotherapy were reviewed. Patients were grouped into those who had or had not received corticosteroid medication as a part of general antiemetic prophylaxis before chemotherapy, and details of hematologic parameters during treatment and disease recurrence-free and overall survival were recorded.

RESULTS

Altogether, 245 patients with ovarian carcinoma had received chemotherapy. Of these, 62 had been given concurrent glucocorticoid treatment and 183 had not. The two patient groups were well balanced with respect to disease stage and other prognostic factors. Kaplan-Meier analyses showed no significant differences in survival between the groups. Patients who received glucocorticoid treatment had significantly higher leukocyte values in the days immediately after chemotherapy, higher nadir leukocyte values, and higher counts before subsequent courses of chemotherapy (P < 0.01; Levene test, t test) compared with patients who did not receive glucocorticoid treatment. As a result, the initial treatment targets were achieved significantly more often in the glucocorticoid group (P = 0.007; chi-square test).

CONCLUSIONS

There was no evidence that glucocorticoid treatment had a negative effect on outcomes in these patients. Glucocorticoids may exert protective effects on the bone marrow.

Optical imaging: bacteria, viruses, and mammalian cells encoding light-emitting proteins reveal the locations of primary tumors and metastases in animals

Early detection of tumors and their metastases is crucial for the prognosis of cancer treatment. Traditionally, tumor detection is achieved by various methods, including magnetic resonance imaging and computerized tomography. With the recent cloning, cellular expression, and real-time imaging of light-emitting proteins, such as Renilla luciferase (Ruc), bacterial luciferase (Lux), firefly luciferase (Luc), green fluorescent protein (GFP), or Ruc-GFP fusion protein, significant efforts have been focused on using these marker proteins for tumor detection. It has also been demonstrated that certain bacteria, viruses, and mammalian cells (BVMC), when administered systemically, are able to gain entry and replicate selectively in tumors. In addition, many tissue/tumor specific promoters have been cloned which allow transgene expression specifically in tumor tissues. Therefore, when light-emitting protein encoded BVMC are injected systemically into rodents, tumor-specific marker gene expression is achieved and is detected in real time based on light emission. Consequently, the locations of primary tumors and previously unknown metastases in animals are revealed in vivo. In the future it will likely be feasible to use engineered light-emitting BVMC as probes for tumor detection and as gene-delivery vehicles in vivo for cancer therapy.

Interstitial laser hyperthermia and the biological characteristics of tumor: study in a murine model of colorectal liver metastases

BACKGROUND DATA

Percutaneously applied interstitial laser hyperthermia (ILH) is a minimally invasive therapy that is currently used in the treatment of liver metastases. Despite its documented efficacy, theoretical considerations and evidence based on animal studies suggest the potential for stimulating tumor growth, especially following surgery. This study investigates the influence of ILH on tumor behaviour in an animal model of colorectal liver metastases.

MATERIALS AND METHODS

A model of colorectal cancer liver metastases in male inbred CBA mice was used. Laser hyperthermia was applied to tumor tissue using a bare optical quartz from a Medilas fibertom 4100 Nd:YAG surgical laser generator. Liver injury by ILH was initially produced in three experimental groups of animals at different time points in the development of metastases. ILH was applied (i) to normal liver 10 days prior to tumor induction, (ii) immediately prior to tumor induction, and (iii) 15 days after tumor induction to achieve approximately 8% liver destruction. Animals were killed 21 days after tumor induction, and the effects of ILH on overall tumor development were compared with controls using stereological assessment of tumor volume and by histology. In a separate experimental group, the effects of ILH on fully established tumors were examined. Suitable tumors were selected 21 days after induction and partially destroyed by ILH at a standard energy setting. Animals were then killed 15 days later, and the growth rate of the residual viable tumors was compared to control tumors having undergone sham procedures.

RESULTS

No significant stimulation of tumor growth was evident in any of the experimental groups following ILH, irrespective of the time of application. Incomplete tumor destruction also had no influence on subsequent tumor growth.

CONCLUSION

ILH does not influence the biological characteristics of tumors during any stage of the metastatic process.

A murine model of bone marrow micrometastasis in breast cancer

Bone marrow (BM) is one of the most common sites and often the first clinical indication of metastatic progression of breast cancer. Multivariate analyses have shown that the presence of cytokeratin positive tumor cells in the marrow of women with newly diagnosed stage I, II or III breast cancer is an independent predictor of survival. The objective of this study was to develop an orthotopic model of spontaneous BM metastasis to facilitate studies of this process. A murine mammary adenocarcinoma cell line, Clone 66, was transduced with the neomycin resistance gene (Cl66neo) and injected orthotopically into female Balb/c mice. Polymerase chain reaction (PCR) for the neo gene performed on BM cells harvested from tumor bearing mice demonstrated as few as 10(2) injected tumor cells produced BM micrometastases at 4 weeks postinjection. Small foci of tumor cells were identified in the mammary fatpad (mfp) without gross evidence of primary tumors. Higher doses of tumor cells produced BM micrometastases, detectable by PCR, at one week post-injection. Constructs containing green fluorescent protein (GFP) and the neomycin resistance gene (neo) were also transduced into Clone 66 cells (Cl66-GFPneo) and injected into the mfp. GFP transduced tumor cells were identified in multiple tissues in addition to BM by flow cytometric analysis (FACS) but less 13% of the animals developed gross metastases. This model is a clinically relevant tool for the analysis of organ specificity of metastasis.

Actions of immunosuppressor drugs on the development of an experimental ovarian tumor

Immunosuppression has been related to the incidence of tumor apparition, including endocrine tumors. The intrasplenic ovarian tumor (luteoma) is a typical benign endocrine tumor that develops under high gonadotropin stimulation and, from the immunological perspective, is located in a critical organ involved in immune response. To establish if immunosuppression could alter the development of this experimental tumor, the effects of cyclosporin A (CsA) and dexamethasone (Dex) were evaluated. After surgery, tumor-bearing and sham animals were kept without treatment for 4 weeks; thereafter, they were distributed into CsA (25 mg/kg), Dex (0.1 mg/kg), or vehicle (75:25 castor oil:ethanol) groups and were injected on alternate days for 50 days. Body weight was evaluated weekly. Animals were sacrificed after a jugular vein blood sample was obtained. Thymi were weighed. Tumors were measured and placed in formaline for histological studies. Serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin (PRL), and estradiol were measured by radioimmunoassay. Hematological parameters were determined. CsA induced a significant decrease in survival rates both in tumor-bearing and sham animals (P < 0.01). Dex significantly impaired weight increase in both groups of animals. CsA induced a significant weight loss in sham animals, not observed in tumor-bearing animals. Dex induced thymus weight loss in both groups, whereas CsA induced thymus weight loss only in sham animals. Only Dex induced a decrease in lymphocyte number in both groups. CsA induced an increase in monocyte number only in sham animals. Treatments did not alter LH, FSH, or estradiol, whereas PRL was increased by CsA only in sham rats. Neither Dex nor CsA induced any significant variations in tumor volume, nor did they alter tumor histology. In addition, no visible metastases or alterations in other organs were observed. We conclude that, though immunological parameters were altered by the treatments, immunosuppressor drugs did not condition tumor development. In addition, tumors secrete one or more factor/s that counteract CsA effect.

Imaging of cancer invasion and metastasis using green fluorescent protein

The use of green fluorescent protein to fluorescently tag tumour cells has allowed investigators to open the "black box" of metastasis in order to visualise the behaviour of tumour cells in living tissues. Analysis of cells leaving the primary tumour indicates that highly metastatic cells are able to polarise more effectively towards blood vessels while poorly metastatic cells fragment more often when interacting with blood. In addition, there appear to be greater numbers of host immune system cells interacting with metastatic tumours. After arresting in target organs such as the lungs or liver, most tumour cells become dormant or apoptose. A small fraction of the arrested cells form metastases. In some target organs, migration of tumour cells may enhance the ability to form metastases.

Interstitial laser coagulation: evaluation of the effect of normal liver blood perfusion and the application mode on lesion size

BACKGROUND AND OBJECTIVE

The effect of temporarily interrupted hepatic blood flow and multiple-fiber application on necrosis volume in interstitial laser coagulation (ILC) was investigated.

STUDY DESIGN/MATERIALS AND METHODS

Single- and multiple-fiber ILC were performed in porcine livers with normal as well as interrupted perfusion. Temperatures were determined. Lesions were measured and studied by light microscopy 4 hours post-treatment.

RESULTS

ILC with multiple-fiber application led to significantly greater individual lesion volumes (3.7 +/- 0.5 cm3) than single-fiber application (2.5 +/- 0.5 cm3) (P < .01). The interruption of hepatic perfusion led to a significant increase in lesion volume with single- (7.5 +/- 1.0 cm3) as well as multiple-fiber application (12.6 +/- 2.2 cm3) (P < .01). Superposition of the lesions in the multiple-fiber application mode was only determined with interrupted perfusion (total volume: 50.3 +/- 6.6 cm3).

CONCLUSION

Interruption of hepatic perfusion increases lesion volumes significantly. ILC for treating liver tumors should preferably be performed by application routes that permit temporary interruption of hepatic perfusion.

Nonhomologous bioinjectable materials in urology: 'size matters'?

OBJECTIVE

To assess the factors that influence how particles might become fixed in tissues or migrate from them, by measuring the size of the injectable particles, their susceptibility to phagocytosis and their affinity for fibroblast attachment in culture.

MATERIALS AND METHODS

The particle size of three types of particulate unphysiological bioinjectable material, i.e. Urocol (Genesis Medical, Ltd., London), Macroplastiquetrade mark (Uroplasty Ltd., Reading, UK) and Urethrin (Mentor Medical Systems, Wantage, UK) was analysed using phase-contrast light microscopy and confocal microscopy. Human monocytes from peripheral blood were incubated with the three materials in phagocytic studies, where ingestion was determined by confocal microscopy. A fibroblast cell line was used to ascertain the ability of the particles to act as a substrate for cell attachment in culture.

RESULTS

The mean (SEM) maximum particle diameters of Macroplastique, Urethrin and Urocol were 209 (5.10) microm, 49 (1.52) microm and 14 (0.39) microm, respectively. Rat peritoneal macrophages and human peripheral blood monocytes commonly ingested Urocol particles; the phagocytosis of Urethrin was rare and that of Macroplastique was not detected. Fibroblasts adhered to Urocol paste and Urethrin particles, but not to Macroplastique.

CONCLUSION

Published reports of particle size and phagocytosis are confusing, but a relationship clearly exists. Macroplastique is the largest particle and is least likely to be phagocytosed by human mononuclear phagocytes. Urocol paste is the slowest to dissipate in culture conditions; the flat surfaces of Urethrin, but not Macroplastique, can serve as a substrate for fibroblast anchorage.

The role of peritoneal immunity and the tumour-bearing state on the development of wound and peritoneal metastases after laparoscopy

BACKGROUND

The effect of the tumour-bearing state and alterations in peritoneal immune function on the incidence of port-site and peritoneal metastases was investigated after laparoscopy with and without CO2 pneumoperitoneum.

METHODS

A suspension of viable adenocarcinoma cells was introduced into the left upper quadrant of the peritoneal cavity of syngeneic tumour-bearing rats at laparotomy, laparoscopy with CO2, and gasless laparoscopy. Control rats did not have pre-existing tumours. A group of non-tumour-bearing rats were also injected intraperitoneally with endotoxin 4 h before intraperitoneal tumour cell injection. Six days later the peritoneal cavity and surgical wounds were examined for macroscopic evidence of implanted tumour. Peritoneal macrophages were obtained from tumour-bearing rats subjected to different laparoscopic procedures and the activation state measured following exposure to lipopolysaccharide in vitro.

RESULTS

In the control rats, tumour implantation in the surgical wounds and peritoneum was significantly greater in the rats that had undergone laparoscopy with CO2. The presence of a pre-existing tumour was associated with increased tumour spread in all treatment groups and at most sites. Injection of endotoxin also resulted in increased tumour spread. Peritoneal macrophages from control and tumour-bearing rats who underwent laparoscopy with CO2 produced significantly less TNF-alpha in vitro, compared to gasless laparoscopy or laparotomy.

CONCLUSIONS

Carbon dioxide insufflation enhances tumour spread and implantation. The underlying immune or metabolic status of the host, as influenced by the tumour-bearing state or modification of the peritoneal environment, also has a marked independent effect on tumour spread and implantation. The immune and metabolic status of the peritoneum including the extent of macrophage activation is implicated in this effect.

Adhesion of colorectal carcinoma cells to the endothelium is mediated by cytokines from CEA stimulated Kupffer cells

We hypothesize that a major factor regulating hepatic metastasis is the ability of CEA (carcinoembryonic antigen) producing colorectal carcinomas to activate Kupffer cells. CEA and NCA (nonspecific cross-reacting antigen) bind to an 80 kDa Kupffer cell receptor by the peptide sequence PELPK and stimulate cytokine production. Cytokines induce sinusoidal endothelial cells to express intercellular adhesion molecules and increase adhesion of the tumor cells and retention in the liver. In this study human Kupffer cells were activated in vitro with CEA, NCA, and the peptide PELPK. This resulted in release of IL-1beta, TNF-alpha and IL-6. CEA non-producing MIP-101 colon carcinoma cells labeled with 51Cr were incubated on monolayers of ECV-304 human umbilical vein endothelial cells treated with these Kupffer cell derived cytokines or with comparable recombinant human (rH) cytokines. Specific antibodies to the adhesion molecules ICAM-1, VCAM-1, E-selectin and beta2integrin were used to block their functions. A significant enhancement in the adhesion of colorectal carcinoma cells occurred when endothelial cells were stimulated with a very low concentration of Kupffer-cell derived cytokines. Activated endothelium demonstrated significant up-regulation primarily of ICAM-1. The adhesion was blocked by an antibody to ICAM-1. A combination of Kupffer-cell derived cytokines was more effective than IL-1beta or TNF-alpha alone. IL-6 alone did not influence adhesion under our conditions. Our results suggest a mechanism for CEA in the modulation of colorectal carcinoma adhesion to the hepatic endothelium and its enhancement of metastatic potential.

Chemokines and their role in tumor growth and metastasis

Chemokines are a superfamily of pro-inflammatory polypeptide cytokines that selectively attract and activate different cell types. Many patho-physiological conditions require the participation of chemokines, including inflammation, infection, tissue injury, allergy, cardiovascular diseases, as well as malignant tumors. Chemokines activate cells through their binding to shared or unique cell surface receptors which belong to the seven-transmembrane, G-protein-coupled Rhodopsin superfamily. The role of chemokines in malignant tumors is complex: while some chemokines may enhance innate or specific host immunity against tumor implantation, others may favor tumor growth and metastasis by promoting tumor cell proliferation, migration or neovascularization in tumor tissue. In this review, the authors summarize some of the recent advances in chemokine research and emphasis is made on the effect of chemokines in tumor growth and metastasis.

Port-site metastasis in the abdominal wall: fact or fiction?

Port-site metastasis (PSM) following minimally invasive surgery (MIS) is discussed and four points are addressed: 1) the occurrence of PSM; 2) the occurrence of PSM as part of distant metastasis, and the need for more studies to confirm that it can occur purely as implantation metastasis; 3) the preliminary experimental evidence suggesting that carbon dioxide might have a role in PSM and that viable cells can be dispersed by pneumoperitoneum (with more experimental work and clinical studies needed to confirm these observations); and 4) some studies showing an increased incidence of PSM after MIS compared with open surgery. Prospective randomized studies with adequate follow-up are needed to establish the validity of such reports.

Purification and identification of chemokines potentially involved in kidney-specific metastasis by a murine lymphoma variant: induction of migration and NFkappaB activation

The ESb-MP cell line is the subclone of a highly malignant variant of murine methylcholanthrene-induced T lymphoma, ESb. When injected in vivo, ESb-MP cells metastasize to the kidney with high frequency, whereas a non-adherent variant, ESb cells, rarely form metastatic foci in the kidney. Our previous results showed that ESb-MP, but not ESb, cells were able to migrate in response to murine kidney-conditioned media (KCM). In an effort to characterize the tumor cell chemoattractant(s) produced by kidney cells, we found that the murine kidney mesangial cell line MES-13 released more chemotactic activity for ESb-MP cells than present in KCM. A major heparin-binding chemotactic activity was purified to homogeneity by sequential fast-performance liquid chromatography and reversed phase high-performance liquid chromatography. Amino acid sequencing of the formic acid-digested active fractions revealed that the purified protein was identical to murine MCP-1(JE) and its activity was neutralized by an anti-MCP-1(JE) antibody. Another chemokine, RANTES, was also purified from MES-13 cell supernatant. The chemotactic activity contained in the MES-13 cell supernatant and in murine KCM was neutralized in part by a combination of anti-MCP-1(JE) and anti-RANTES antibodies. We further examined the differences in the ESb-MP and ESb cells. Binding studies using a variety of radio-iodinated chemokines showed that although both ESb-MP and ESb cells expressed substantial levels of high-affinity binding sites for CC chemokines, only ESb-MP cells migrated in response to CC chemokines and these cells constitutively expressed higher levels of beta2 integrin adhesion protein CD11b than their parental ESb cells. CC chemokines also activated NFkappaB in ESb-MP but not in ESb cells. Our results indicate that CC chemokines selectively chemoattract and activate ESb-MP cells. Thus, locally produced chemokines, MCP-1(JE) and RANTES in particular, may contribute to the preferential metastasis of ESb-MP cells to the kidneys.

Impact of gas(less) laparoscopy and laparotomy on peritoneal tumor growth and abdominal wall metastases

OBJECTIVE

A tumor model in the rat was used to study peritoneal tumor growth and abdominal wall metastases after carbon dioxide (CO2) pneumoperitoneum, gasless laparoscopy, and laparotomy.

SUMMARY BACKGROUND DATA

The role of laparoscopic resection of cancer is under debate. Insufflation of the peritoneal cavity with CO2 is believed to be a causative factor in the development of abdominal wall metastases after laparoscopic resection of malignant tumors.

METHODS

In the solid tumor model, a lump of 350-mg CC-531 tumor cells was placed intraperitoneally in rats having CO2 pneumoperitoneum (n = 8), gasless laparoscopy (n = 8), or conventional laparotomy (n = 8). After 20 minutes, the solid tumor was removed through a laparoscopic port or through the laparotomy. In the cell seeding model, 5 x 10(5) CC-531 cells were injected intraperitoneally before CO2 pneumoperitoneum (n = 12), gasless laparoscopy (n = 12), or laparotomy (n = 12). All operative procedures lasted 20 minutes. After 6 weeks, in the solid tumor model and after 4 weeks in the cell seeding model, tumor growth was scored semiquantitatively. All results were analyzed using the analysis of variance.

RESULTS

In the solid tumor model, peritoneal tumor growth in the laparotomy group was greater than in the CO2 pneumoperitoneum group (p < 0.01). Peritoneal tumor growth in the CO2 group was greater than in the gasless group (p < 0.01). The size of abdominal wall metastases was greater at the port site of extraction of the tumor than at the other port sites (p < 0.001). In the cell seeding model, peritoneal tumor growth was greater after laparotomy in comparison to CO2 pneumoperitoneum (p < 0.02). Peritoneal tumor growth in the CO2 group was greater than in the gasless group (p < 0.01). The port site metastases in the CO2 group were greater than in the gasless group (p < 0.01).

CONCLUSIONS

The following conclusions can be made: 1) that direct contact between solid tumor and the port site enhances local tumor growth, 2) that laparoscopy is associated with less intraperitoneal tumor growth than laparotomy, and 3) that insufflation of CO2 promotes tumor growth at the peritoneum and is associated with greater abdominal wall metastases than gasless laparoscopy.

Interferon-beta prevents the upregulation of interleukin-8 expression in human melanoma cells

The constitutive expression of interleukin-8 (IL-8) by human melanoma cells correlates with their metastatic potential. The exposure of human melanoma cells to the inflammatory cytokines IL-1 beta or tumor necrosis factor-alpha (TNF-alpha) upregulated IL-8 expression in a time-dependent and concentration-dependent manner. This enhanced expression of IL-8 was inhibited by cycloheximide or actinomycin-D. Treatment of melanoma cells with interferon (IFN) alpha, beta, or gamma did not affect the constitutive expression of IL-8, but IFN-alpha and IFN-beta blocked the upregulation of IL-8 expression in cells treated with IL-1 beta or TNF-alpha subsequent to or simultaneously with the IFN. These data suggest that the expression of IL-8 in human melanoma cells can be upregulated by inflammatory cytokines and that IFN-alpha and IFN-beta can counterregulate this stimulation.

Targeting the epidermal growth factor receptor for therapy of carcinomas

As a group, the carcinomas represent a substantial proportion of all human malignancies, but, with relatively few exceptions, current treatments are ineffective. Modification of existing chemotherapeutic agents has not led to significant improvements in the survival of carcinoma patients, and development of new therapeutic strategies is imperative. It is now becoming apparent that activation of the epidermal growth factor receptor (EGF-R) has much wider implications than a straightforward stimulation of cell division. The pleiotropic effects of EGF-R signalling may influence tumour behaviour and the response of carcinomas to treatment; these are important considerations for the development of new therapies that aim to exploit the expression or modulate the function of the EGF-R in these tumours.

Liver metastases from colorectal cancer: lessons from past and present clinical studies

In patients with primary colorectal cancer the development of liver metastases has traditionally been equated with imminent demise. This metastatic event is remarkably common; indeed, liver metastases are present in some 25 per cent of patients at the time of initial colorectal resection and over 50 per cent of patients will eventually develop them. Some 90 per cent of patients who die from colorectal cancer have liver metastases. There are few cancers in which the metastatic pattern has such a high degree of predictability. Information from past and present clinical studies should, therefore, provide a basis for logical approaches to prevention and treatment.

Role of cytokines and growth factors in promoting the local recurrence of breast cancer

The pathogenesis of local recurrence in breast cancer is not well understood. Breast-conserving surgery is particularly prone to local recurrence as it leaves behind breast tissue that may harbour occult cancer, and lends itself to enhanced intraoperative shedding of cancer cells due to narrower resection margins and transection of lymphatic channels. A review of clinical breast cancer studies as well as experimental research strongly suggests that these persisting cancerous cells are unlikely to develop into clinically evident disease if their environment remains unstimulated. However, an inordinately high local recurrence rate occurs at the surgical scar, and such recurrence must be triggered by the release of growth factors and cytokines into the healing wound. These factors can stimulate any available cancer cells which express the proper growth factor receptors. Perioperative strategies to neutralize this tumour cell-growth factor interaction should maximize local control.

The effect of partial hepatectomy on tumor growth in rats: in vivo and in vitro studies

Residual tumor in the remnant liver after partial hepatectomy (PH) for colorectal liver metastases is a serious clinical problem. This fact is reflected by the high number of recurrences after potentially curative liver resections. Liver regeneration, it appears, might influence the growth of remaining micrometastases in the liver. Using rats, we demonstrated enhancement of growth of a syngeneic colon carcinoma (CC 531) in the remnant liver after 70% PH. Fourteen days after PH, tumor weights in the liver were twice as high as those of sham-operated rats. This difference in tumor weight was not found in extrahepatic tumors. In vitro experiments did not show stimulation of cultured CC 531 cells by portal or systemic serum withdrawn 24 hours or 14 days after hepatectomy as compared with sera obtained after sham operation. Co-cultures of CC 531 cells and hepatocytes (in ratios of 1:10 or 1:1) demonstrated a higher 3H-thymidine incorporation than was the case in separately cultured cells. In co-cultures, bromodeoxyuridine (BrdU) incorporation in DNA was found primarily in CC 531 cells and rarely in hepatocytes. Cell density appeared to be of influence on 3H-thymidine incorporation in co-cultures. Hepatocytes were found to have a stimulating effect on CC 531 cells in low-density cultures, whereas high-density cultures exhibited an inhibiting effect after a culture time of 120 hours. These results show that, depending on cell density in co-cultures, a paracrine stimulating influence of hepatocytes on this type of colon carcinoma cells (CC 531) might be responsible for the increased tumor growth in vivo.

Dexamethasone enhances colonization of soft agar by tumorigenic mouse lung-derived cell lines

When cultured on plastic, tumorigenic mouse lung-derived cell lines exhibit different proliferative responses to glucocorticoids; some lines are inhibited while others are stimulated or unaffected. In contrast to the variable dexamethasone responses when cells are cultured on plastic, soft agar colonization by each of these cell lines is enhanced by dexamethasone. Enhanced soft agar growth is unlikely to result from expression of a mutant glucocorticoid receptor, since dexamethasone also enhanced colony formation in two cell lines that stably express a transfected normal glucocorticoid receptor gene. Thus, cell attachment influences the effect of glucocorticoids on cell cycle progression.

Contribution of host-derived growth factors to in vivo growth of a transplantable murine mammary carcinoma

The contribution of host-derived growth factors to tumour growth in vivo was studied using the transplantable murine mammary carcinoma, MT1, grown in syngeneic mice. Promotion of growth of the mammary carcinoma by a factor(s) from the host was evident in experiments in which the carcinoma cells were inoculated intraperitoneally. In this environment, tumours develop as multiple solid nodules, each probably arising from an individual cell or a small cluster of cells. Tumour growth was found to occur in the peritoneal cavity following inoculation of 10(3) cells, but an inoculum of as few as ten cells grew if a leucocyte-rich exudate had first been induced. To determine which host-derived growth factors might contribute to growth of MT1, extracts of the tumour were first examined for growth factor activity. Fractionation of tumour extracts by either ion-exchange chromatography or gel filtration revealed several peaks of mitogenic activity, but none of this could be attributed to epidermal growth factor (EGF). Accordingly, an anti-EGF antibody was tested as a putative inhibitor of tumour growth as any effect of this antibody could be ascribed to removal of EGF derived from the host. The antibody was found to have potent anti-tumour activity when tested against MT1 tumours that had been inoculated into the peritoneal cavity. In contrast, the antibody had little effect on growth of the discrete tumour mass which formed when MT1 was transplanted subcutaneously. The results suggest that host-derived EGF contributes to establishment of microcolonies of MT1 carcinoma within the peritoneal cavity. This may be directly, by providing growth factors to supplement those produced by the tumour until it reaches a certain critical mass to sustain autocrine growth, or indirectly, by affecting the production of other growth-stimulatory factors or cytokines.

Effect of trauma on implantation of metastatic tumor in bone in mice

We studied the influence of surgical trauma to the iliac bone on the implantation of I.V. injected tumor cells, which formed tumor in the surgical wounds of 27/84 mice (32%). None of these mice or nonsurgical mice developed tumor in the opposite or uninjured pelvic bone (P < 0.0001). When different numbers (10(5), 5 x 10(5), and 10 x 10(5)) of TA3Ha cells were injected I.V. immediately after surgery, the frequency of tumor formation showed an increase (respectively, 32%, 63%, 71%). As the interval between induction of trauma and tumor cell injection was increased from 0 to 15 days, the frequency of tumor formation declined from 32% to 0%. These results suggest that the healing wound is a privileged site for experimental metastasis, particularly in the early stages. It is likely that the proteins in the blood clotting cascade are involved in local tumor implantation.

Abdominal wall metastases following laparoscopy

Only 18 cases of recurrence at the sites of cannula insertion after laparoscopy have been reported in the literature, ten of them in the past year. The period between laparoscopic surgery and presentation of wound metastasis varies widely, from 7 days to 10 months; the lesions are typically hard, craggy and painful. The most likely mechanism is direct implantation of viable exfoliated tumour cells but three aspects specific to laparoscopy may also be important. First, there may be increased exfoliation of tumour cells following manipulation by laparoscopic instruments of an unsuspected malignancy. Second, there may be repeated close contact between tumour-laden instruments and the port. Third, the passage of resected tissue through a small incision may coat the wound with potentially malignant cells.

The importance of blood cell-vessel wall interactions in tumour metastasis

Tumour cell dissemination is a complex process, depending on the ability of malignant cells to escape from the primary tumour and penetrate and flow through the bloodstream. Circulating tumour cells can adhere to the vessel wall, dissolve the basal lamina and extravasate, giving origin to metastases. Interactions between tumour cells, blood platelets and leukocytes favour tumour cell adhesion to the vessel wall, migration in extravascular spaces and growth in secondary sites. The biochemical and molecular mechanisms regulating tumour cell adhesion to the vessel wall and intercellular contacts have been studied extensively in recent years. Moreover, it has been shown that either tumour cells or blood cells release growth factors and inflammatory proteins, such as cytokines and chemokines, that may be involved in tumour cell migration and proliferation. Finally, tumour cells and cells of the surrounding tissue possess procoagulant and fibrinolytic properties that may be important in modulating the extracellular matrix around the tumour, to allow tumour cell invasion and progression. We have described the cell types (i.e. blood platelets, leukocytes, endothelial cells), the matrix components (i.e. fibronectin, thrombospondin and laminin) and the growth factors/cytokines (i.e. platelet-derived growth factor, transforming growth factor beta, tumour necrosis factor) involved in these processes. In particular, we have described cell-cell and cell-matrix interactions, cell migration and release of growth factors, cytokines, chemotactic peptides and proteolytic enzymes. This survey has also considered a few innovative approaches for the prevention and cure of cancer and metastasis that are based on these new concepts.

Effect of fibrin sealant on perianastomotic tumor growth in an experimental model of colorectal cancer surgery

Viable intraluminal tumor cells can penetrate a clinically intact rodent colonic anastomosis and give rise to perianastomotic tumor growth. The aim of this study was to determine whether transanastomotic cell migration can be prevented by fibrin-based tissue sealant. Following distal colonic transection and reanastomosis with 5/0 silk sutures, Fischer F344 rats were randomly allocated to three experimental groups. In Group A, a circumferential ring of tissue sealant was placed around the serosal surface of the anastomosis; in Group B, sealant was limited to 50 percent of the anastomotic circumference; and, in Group C, no sealant was applied. All rats then had 10(5) Mtln3 carcinoma cells injected into the proximal colonic lumen via a rectal catheter. The incidence of perianastomotic tumor at 21 days was significantly lower in Group A (3 of 14 animals) than in Group B (11 of 16 rats) (P = 0.012; Fisher's exact test) or Group C (10 of 14 rats; P = 0.011). A further experiment demonstrated that sealant did not protect the anastomosis when tumor cells were instilled directly into the peritoneal cavity. A topical carcinocidal action therefore appears unlikely, but our results suggest that a circumferential anastomotic ring of fibrin sealant forms an effective mechanical barrier preventing intraluminal tumor cells from reaching the peritoneal cavity.

Importance of E-selectin (ELAM-1) and sialyl Lewis(a) in the adhesion of pancreatic carcinoma cells to activated endothelium

Adhesion molecules involved in attachment between human pancreatic carcinoma and activated endothelial cells in vitro were investigated. Basal adhesion occurred between 6 pancreatic carcinoma cell lines and unstimulated human umbilical vein endothelial cells (HUVEC), and augmented basal adhesion to activated HUVEC was only seen when pancreatic cancer cells expressed sialyl Lewisa (SLea) and sialyl Lewisx (SLex). Activation of HUVEC with interleukin 1-beta (IL-1 beta) or tumor necrosis factor-alpha (TNF-alpha), but not with interferon-gamma (IFN-gamma), generated the augmentative basal adhesion. Dose dependence and additive effect were observed in augmentation of the basal adhesion induced by IL-1 beta and/or TNF-alpha. Increase in adhesion correlated with up-regulation of the surface E-selectin (or ELAM-1) on HUVEC, and was evident at both 25 degrees C and 4 degrees C. Anti-E-selectin and anti-SLea blocked the augmented attachment, whereas anti-SLex, an antibody against another known ligand for E-selectin, did not. The collective evidence indicates that attachment between pancreas carcinoma cells and activated endothelial cells is regulated by cytokines such as IL-1 beta and TNF-alpha, and is mediated by SLea on pancreas carcinoma and E-selectin on endothelial cells. These molecules may be of significant importance in blood-borne metastasis of pancreatic carcinoma cells to inflamed sites.

Effect of suture material on tumour cell adherence at sites of colonic injury

In an experimental animal model, radiolabelled viable intraperitoneal adenocarcinoma cells adhered in similar numbers to normal rat colon and that injured by a 1-cm colotomy, with median cell counts of 7002 and 8602 respectively (P not significant). Repair of the colotomy with interrupted silk resulted in a significant increase in the median number of cells adhering to the injury site (21,888; P = 0.0001 versus normal colon). Repair with Prolene had no effect on tumour cell adherence (a median of 7449 cells adhered; P not significant versus normal colon). Tumour cell adherence at sites of colonic injury is dependent on the suture material used and not on the injury itself in this model. This may be important when choosing suture type for anastomosis in patients undergoing surgery for colorectal cancer.

Patterning of B16 melanoma metastasis and colonization generally relates to tumor cell growth-stimulating or growth-inhibiting effects of organs and tissues

The mouse B16 melanoma metastasizes first to the lungs and secondarily to systemic sites, involving mainly the adrenals, ovaries and pancreas. Systemic colonization effected by intracardiac injection of tumor cells establishes similar patterning, but in addition frequently colonizes the bones. To assess possible systemic site influences on metastasis and colony formation, the capacity of B16 melanoma cells to proliferate in these sites in vivo and in ex vivo explants following intracardiac injection was examined. Effects of cells isolated from these sites, and of organ- or tissue-conditioned medium, on growth of B16 cells in monolayer culture were also studied. Injected fluorochrome-labeled tumor cells initially distributed without site preference, but within 48 h had begun proliferating in the adrenals, ovaries and lungs, while remaining static in the pancreas and bones, and disappearing from the spleen, liver, kidneys, brain, and skeletal muscles. Mitogenic activity releasable in soluble form was associated with all favorable organs and tissues and was the predominant influence of those tissues on cultured tumor cells. In contrast, the overall effects of liver, spleen, kidney, and brain tissues were to inhibit tumor cell growth. Soluble growth-promoting activity enhanced clonogenic growth of isolated tumor cells stimulated by mouse serum, suggesting that metastasis or colony formation might be stimulated in favorable sites by those factors together with blood-borne growth factors. The observed effects of organ- and tissue-derived cells and soluble factors on tumor cells generally reflected the in vivo consequences of tumor cell entrapment in the corresponding sites. However, the failure of metastases to develop in the bones, which are favorable sites for colonization by the same cells, remains puzzling.

Blocking of lung endothelial cell adhesion molecule-1 (Lu-ECAM-1) inhibits murine melanoma lung metastasis

The 90-kD lung endothelial cell adhesion molecule-1 (Lu-ECAM-1) selectively promotes Ca(2+)-dependent adhesion of lung-metastatic B16 melanoma cells. Corresponding with their metastatic performance, high lung-metastatic B16-F10 melanoma cells bind in significantly higher numbers to Lu-ECAM-1 than their intermediate and low lung-metastatic counterparts B16-L8-F10 and B16-F0, respectively. Maximum attachment is observed at a density of approximately 2.4 x 10(2) Lu-ECAM-1 sites/microns2 of plastic surface. B16 melanoma cell binding to Lu-ECAM-1 is blocked by mAb 6D3 and is competitively inhibited by soluble Lu-ECAM-1. C57B1/6 mice passively immunized with anti-Lu-ECAM-1 mAb 6D3 or actively immunized with purified Lu-ECAM-1 exhibit an anti-Lu-ECAM-1 antibody titer-dependent reduction in the number of B16 experimental metastases. Lu-ECAM-1 promotes neither binding nor metastasis of other lung-metastatic tumor cells (e.g., KLN205). Our data indicate that an "antiadhesion" therapy directed at interfering with the adherence of blood-borne tumor cells to organ-specific vascular endothelium is efficient in the control of metastasis formation in selective organ sites.

Tissue procoagulant activity may be important in sustaining metastatic tumour growth

There is strong evidence for an association between the haemostatic system and malignancy. Thus, cancer may adversely affect the host coagulation system while the haemostatic system may play a role in the development of both primary and metastatic tumours. Metastatic growth is not dependent simply on haemodynamic factors, and properties of both the tumour cell and host organ are important determinants of the site of metastatic growth. Previous studies have demonstrated that some organs are preferred sites for metastasis while others are less preferred or resistant. We have measured the procoagulant activity (PCA) of normal rat and human tissues and correlated the results with the previously reported ability of these organs to support metastatic tumour growth. In addition, we determined changes in PCA in rat tissues during oral anticoagulant therapy, and following colonic anastomosis and partial hepatectomy, procedures which are known to affect experimental metastasis. In both rat and human studies, organs which are preferred sites for metastasis had significantly higher PCA than non-preferred organs (P less than 0.001). The PCA of adrenal, lung and colon was significantly reduced by administration of warfarin (P less than 0.001). PCA was significantly (P less than 0.001) increased in both colonic anastomoses and regenerating liver and followed a time course similar to that of the enhanced tumour growth usually seen in these situations. Although the exact source of the procoagulant activity remains to be determined, the results suggest that there is a broad correlation between tissue PCA and the ability of a tissue to support metastatic tumour growth.

Tumour necrosis factor-alpha stimulates invasiveness of T-cell hybridomas and cytotoxic T-cell clones by a pertussis toxin-insensitive mechanism

Tumour necrosis factor-alpha (TNF-alpha) stimulated invasion by mouse T-cell hybridomas and cytotoxic T-lymphocyte clones into rat embryo fibroblast monolayers. The effect on these highly invasive cells was limited: invasion was stimulated maximally to 130% of controls. However, when cells were pretreated with pertussis toxin (PT), which inhibits invasion to +/- 20% of controls, a clearcut effect was observed: 400 U TNF-alpha per ml stimulated invasion usually two- to threefold, and sometimes even up to 10-fold. Therefore, experiments were done with PT-pretreated cells. Stimulation was dose dependent and maximal at 200-400 U TNF-alpha per ml. An anti-TNF-alpha monoclonal antibody completely abolished TNF-alpha-induced invasion. The effect was maximal 30 min after addition of cells and TNF-alpha to the monolayer and then declined. TNF-alpha preincubation of T-cell hybridoma cells, but not of fibroblasts, had a similar stimulatory effect, which was also maximal after 30 min. This shows that TNF-alpha acts directly on the T-cell hybridoma cells. Invasive T-cell hybridomas colonize many tissues from the blood similarly as normal T cells. Our data thus suggest that TNF-alpha can stimulate migration of normal T lymphocytes into inflamed tissues and can promote metastasis of malignant T lymphomas. The signals involved are transmitted via a pertussis toxin-insensitive pathway.

Expression and secretion of leukocyte chemotactic cytokines by normal human melanocytes and melanoma cells

The capacity of human melanocytes and melanoma cells to produce IL-8 and monocyte chemotactic and activating factor (MCAF) was investigated. Melanocytes expressed mRNA for IL-8 and MCAF, when stimulated with either IL-1 alpha or TNF alpha, but not when stimulated with IL-6, IFN gamma, or LPS alone. IL-8 and MCAF could be induced in a dose-dependent fashion with doses as low as 0.1 ng/ml TNF alpha and 0.5 ng/ml IL-1 alpha. IL-8 and MCAF mRNA were rapidly expressed and peaked between 2 and 4 h for IL-8 and between 4 and 8 h for MCAF. This correlated well with the accumulation of IL-8 antigen as measured by a radioimmunoassay. Supernatants from melanocyte cultures stimulated with either IL-1 alpha or TNF alpha and separated on a heparin-Sepharose column became positive for neutrophil and monocyte chemotactic activity in a dose- and time-dependent fashion. When IFN gamma was added to melanocyte cultures stimulated with suboptimal doses of TNF alpha there was a synergistic increase in secreted IL-8 protein and monocyte chemotactic activity. These data provide further evidence for the possible role of melanocytes in the initiation of an inflammatory reaction. Three different malignant melanoma cell lines stimulated with either TNF alpha or IL-1 alpha expressed IL-8 mRNA, but not mRNA for MCAF. The IL-8 mRNA signal corresponded well with the amount of secreted IL-8 protein. These data suggest that IL-8 and MCAF may play a role in growth regulation and spreading of melanomas.

Facilitation by partial hepatectomy of tumor growth within the rat liver following intraportal injection of syngeneic tumor cells

The effects of both mechanical trauma and regeneration on the growth of intraportally injected tumor in the rat liver were investigated using two-thirds partial hepatectomy (PH). Tumor grew at the excision scar when PH was performed less than 2 days before tumor injection (34/34 animals). However, when the PH was performed 4-7 days before injection, tumor developed within the regenerating lobe, but not at the scar (50/51). Injecting the same cell dose into rats with intact livers caused few tumors to develop in 12/30 animals. Intraportally injected 51Cr-labelled tumor cells distributed uniformly in the liver irrespective of the time after PH. Patterns of tumor take seen at different times after PH were not due to selective trapping of the injected cells. Liver extracts showed that epidermal growth factor-like activity was unaltered by PH, while heparin-binding growth factor activity peaked at 2 days post-PH, before the incidence of tumor growth in the parenchyma increased. We observed two peaks of DNA synthesis at days 1 and 4 post-PH by pulse labeling with [125I]deoxyuridine and bromodeoxyuridine. Bromodeoxyuridine immunohistochemistry showed the first peak to be confined to hepatocytes. The second peak involved non-hepatocytes and coincided with the beginning of enhanced tumor take in the regenerating lobe.

Differential influence of organ site on three subpopulations of a single mouse mammary tumor at two distinct steps in metastasis

Tumor subpopulations 66c14, 168FARN, and 4T07 are drug-resistant variants selected from sister subpopulations derived from a single mouse mammary tumor. These subpopulations are heterogeneous in their capacities to form experimental metastatic growth in the lungs and liver. Initial survival kinetics of arrested cells, determined by the clearance of 125IUdR-labelled cells, and subsequent growth rates, determined by sequential recovery of clonogenic tumor cells from occult metastases, both correlated with organ-colonizing potential as determined by necropsy. The growth rates of these 3 subpopulations were determined in vitro in monolayer and in situ in the subcutis, in the liver following intrasplenic injection, and in the lung following intravenous injection. Clonogenic potential of all 3 lines was similar in vitro (54-59%). Growth rates in vitro (population doubling times 16.5-21 hr) and in the subcutis (tumor volume doubling times 5.2-7.4 days) were similar for the 3 subpopulations, but differed significantly in the liver and lungs. For line 4T07, the most metastatic line to both lung and liver, population doubling times in vitro and in the lung and liver were similar, ranging from 17 to 26 hr. For lines 66c14 and 168FARN, the growth rates in lungs and livers were much slower than in vitro. Line 66c14, which is relatively more metastatic to the lungs, grew much faster in the lung (39 hours) than in the liver (91 hr), but line 168FARN, which is relatively more metastatic to the liver, grew at a faster rate in the liver (37 hr) than in the lung (63 hr). Thus, 3 tumor subpopulations (seeds) derived from a single tumor were differentially affected by host organ factors (soil) at 2 distinct stages in the metastatic process.