Localization of sunitinib, its metabolites and its target receptors in tumour-bearing mice: a MALDI-MS imaging study

BACKGROUND AND PURPOSE

The clinical effects of anti-angiogenic agents remain controversial. Therefore, elucidating the pharmacological properties of these compounds is a pivotal issue.

EXPERIMENTAL APPROACH

The effects of treatment with sunitinib on tumour and normal tissues of mice bearing C-26 adenocarcinoma cells were analysed by matrix-assisted laser desorption ionization MS imaging (MALDI-MSI). Expression of the key targets of sunitinib--angiogenic receptors--was studied by immunofluorescent labelling.

KEY RESULTS

MALDI-MS assays showed that sunitinib and its fragment ions were present throughout tumour and normal tissues. Major metabolites were identified in blood and solid tissues, while minor drug metabolites were detectable only in blood. Tumour growth and intratumour VEGF receptor-2 expressions were significantly reduced in sunitinib-treated mice, while the expression of the other targeted receptors, PDGF receptor -α or -β and fibroblast growth factor receptor-1, remained unaffected. Within tumour tissue, the close proximity of sunitinib metabolites to the precursor ion suggested in situ metabolism of the administered drug. There were intratumour areas where the signal intensity of sunitinib correlated with expression of VEGF receptor-2.

CONCLUSIONS AND IMPLICATIONS

This is the first study that demonstrates MALDI-MSI is a versatile platform to study the intratumour localization of an unlabelled anti-angiogenic drug. The combination of MALDI-MSI and immunofluorescence analysis can provide further insights into the molecular interaction of drug compounds and their targets within tumour tissue.

Circulating endothelial progenitor cells and depression: a possible novel link between heart and soul

Although depression is known to be an independent risk factor for cardiovascular disorders, the mechanisms behind this connection are not well understood. However, the reduction in the number of endothelial progenitor cells (EPCs) in patients with cardiovascular risk factors has led us to hypothesize that depression influences the number of EPCs. EPCs labeled with CD34, CD133 and vascular endothelial growth factor receptor-2 (VEGFR2) antibodies were counted by flow cytometry in the peripheral blood (PB) of 33 patients with a current episode of major depression and of 16 control subjects. Mature (CD34+/VEGFR2+) and immature (CD133+/VEGFR2+) EPC counts were decreased in patients (vs controls; P<0.01 for both comparisons), and there was a significant inverse relationship between EPC levels and the severity of depressive symptoms (P<0.01 for both EPC phenotypes). Additionally, we assayed the plasma levels of VEGF, C-reactive protein (CRP) and tumor necrosis factor (TNF)-alpha and observed significantly elevated TNF-alpha concentrations in patients (vs controls; P<0.05) and, moreover, a significant inverse correlation between TNF-alpha and EPC levels (P<0.05). Moreover, by means of a quantitative RT-PCR approach, we measured CD34, CD133 and VEGFR2 mRNA levels of PB samples and found a net trend toward a decrease in all the investigated EPC-specific mRNA levels in patients as compared with controls. However, statistical significance was reached only for VEGFR2 and CD133 levels (P<0.01 for both markers). This is the first paper that demonstrates evidence of decreased numbers of circulating EPCs in patients with a current episode of major depression.

Systematic investigation of different steroid precursors with respect to their effect on superoxide anion production by human neutrophil granulocytes

Free radicals are involved in several pathological processes in living organisms, for example in athero- and oncogenesis. Some steroids are known to be effective antioxidants, while others do not play any such role. The aim of our study was to examine the antioxidant capability of different metabolites in the synthesis of steroid hormones. As a model, we chose human neutrophils producing superoxide anion, which is the source of many other radicals. Neutrophils were separated from healthy volunteers. Isolated cells were incubated with varying concentrations of steroid compounds and stimulated with N-formyl-Met-Leu-Phe. Superoxide anion production was determined by photometry. Neutrophils incubated with corticosterone and 18-hydroxy-deoxycorticosterone showed a significant reduction in superoxide production, whereas we found a significant enhancement in the presence of 11beta-hydroxyprogesterone. Furthermore, we observed a non-significant decreasing trend after incubation with cholesterol 3-sulphate and an increasing tendency using 11-hydroxyandrostenedione. We were also able to produce newer morphological and functional evidence of the role of myeloperoxidase enzyme in the steroidal antioxidant effect by electronic microscopy and use of sodium hypochlorite in our incubation model. Based on these results, we conclude that not only steroid end products but also their intermediate metabolites, most of which are also present in human plasma, partly influence free radical metabolism. Thus, this study provides further argument for the search for the molecular basis responsible for the antioxidant effect of steroid structures. This may lead to new opportunities for finding really efficient antioxidants, which might perhaps be used in a combined manner with other agents in the fight against certain life-threatening diseases.

Expression of a decorin-like moleculein human melanoma

Decorin, a member of the family of small leucin-rich proteoglycans, has originally been described as a secreted proteoglycan component of the connective tissues, and has been implicated in the negative regulation of cell proliferation directly or via interactions with TGF-beta. It was reported to be generally absent from tumor cells. Here we show that human melanoma cell lines express a decorin-like molecule. We detected decorin mRNA by RT-PCR in 7 out 7 human melanoma lines characterized by various metastatic potential. Using polyclonal antiserum against the core protein of decorin, the typical 80-120 kD glycanated form as well as a high molecular weight aberrant version (200-210 kD) of decorin were demonstrated by Western blot technique in the culture supernatants as well as in lysates of human melanoma cells. Finally, decorin epitope was also demonstrated immunohistochemically in human melanoma xenografts, as well as in tumor cells of surgically resected melanomas but not in melanocytes of nevi. The expression of this aberrant decorin did not inhibit the in vitroor in vivogrowth of human melanoma cells, and it was independent of their metastatic potential. Human melanoma cell lines expressing aberrant decorin retained sensitivity to the antiproliferative and gelatinase-stimulatory effects of exogenous TGF-beta.

Organ-specificity of the extravasation process: an ultrastructural study

The process of extravasation of the high metastatic Lewis lung carcinoma line was examined in different organs. Four of the five organs (liver, lungs, brain and adrenals) represent the most frequent metastatic sites in humans. In the case of each organ 150-350 tumor cells were analysed. The interaction of tumor cells with endothelial cells and the basement membrane showed significant differences between the organs. In the liver and lungs, endothelial cells were found to migrate onto the surface of the tumor cells, resulting in the removal of tumor cells from the circulation. The process was initiated by development of cytoplasmic projections on the luminal surface of the endothelial cells. In the liver only half of the tumor cells showed basement membrane degradation even after 24 h, although 6 h after injection 40% of the tumor cells were sequestered from the circulation. In the adrenals and brain, tumor cells were not covered by endothelial cells instead, limited retraction of endothelial cells was followed by penetration of the basement membrane. In the kidney both types of tumor cell-endothelial cell interactions were observed, but the process of extravasation was not completed, stopping as the tumor cells reached the basement membrane or the mesangial matrix. The time course of tumor cell extravasation also showed significant differences between the organs. The process was most rapid in case of the liver and adrenals. By 6 h 40-50% of the tumor cells were in the process of extravasation or were in an extracapillary position. These organs are preferential metastatic sites of this tumor line. The time of extravasation was much longer in the other organs (lungs 16 h, brain 48 h), for which this tumor line shows no preference.

CONCLUSIONS

(1) Type and duration of tumor cell extravasation differ between the organs. (2) The time needed to reach extraluminal position, but not the type of extravasation correlates with the organ preference. (3) Endothelial cells of the lungs and liver can play a much more active role in the process of extravasation than previously suggested. (4) Tumor cells can complete the metastatic process without reaching a complete extracapillary position; contact with the basement membrane or extracellular matrix seems to be sufficient.

Progression difference between cancers of the larynx and hypopharynx is not due to tumor size and vascularization

A recent survey of head and neck cancer indicated a sharp difference in survival between cancer of the hypopharynx and cancers formed in other head and neck sites. We have analyzed tumor size relative to clinical stage and vascularization as possible causes for such a difference in a series of 21 patients with cancer of the laryngopharynx (11 glottic and 10 hypopharyngeal). We found that the volume of the smallest cancers of the larynx at stage 2 is significantly larger than the volume of the cancers of the hypopharynx at stage 4 (P < 0.05). Next, we have determined by immunohistochemistry and morphometry the microvessel density, microvessel perimeter, and vascular endothelial growth factor (VEGF) expression of laryngo-hypopharyngeal cancers. Analysis of these data indicates that there is no difference in vascularization and VEGF expression between these two tumor types. These data strongly suggest that the invasive but not the angiogenic phenotype of hypopharyngeal cancer cells could be responsible for the more aggressive biologic behavior of this head and neck cancer subtype.

Connexin 43 expression in rat aortic smooth muscle after ovariectomy and hormonal replacement

The purpose of this study was to determine the effects of ovariectomy and long-term combined sexual hormone replacement on the gap junctional protein, connexin 43 (Cx43) of aortic medial smooth muscle cells in rats. Twenty non-pregnant mature Wistar female rats were divided into five groups (four animals in each group). Group A underwent ovariectomy, Group B underwent ovariectomy and received estradiol propionate, Group C underwent ovariectomy and received medroxyprogesterone acetate and Group D underwent ovariectomy and received both hormones. Group E was sham-operated and used as control. After 15 weeks of treatment, thoracic aortas were removed and immunohistochemistry was carried out using a specific fluorescent antibody against Cx43. Tissue sections were examined by confocal laser scanning microscopy and analysed by the Scion Image program. All five different groups had the same distribution and extent of Cx43 in the aorta. Neither the ovariectomy nor the hormone replacement had any effect on the Cx43 expression of aortic smooth muscle cells in rats as compared to control animals. These results indicate that sexual steroids do not influence the gap junctional protein Cx43 of the medial layer of aorta in rats. They may suggest that the beneficial effects of estrogen are not mediated via gap junctions in the human aorta either.

Ectopic alphaIIbbeta3 integrin signaling involves 12-lipoxygenase- and PKC-mediated serine phosphorylation events in melanoma cells

Megakaryocytic genes such as alphaIIbbeta3 can be expressed by malignant cells as part of the disturbances in their gene regulation. However, the function of the gene product greatly depends on the interaction of the ectopic protein with the new environment. The outside-in signaling of the ectopically expressed alphaIIbbeta3 integrin was studied in B16a murine melanoma cells using a monoclonal antibody, specifically directed to the activated conformation of alphaIIbbeta3, PAC-1 and the physiological ligand, fibrinogen. Ligation of alphaIIbbeta3 induced down-regulation of FAK but serine phosphorylation of three protein bands, 20/21, 85 and 140 kDa within 1-15 min. Flow cytometry indicated that the ligation of the receptor in B16a cells induces approximately 50% increase in phosphoserine positive cells within 5-15 min. 12-lipoxygenase is placed downstream in the signaling pathway, since ligation of alphaIIbbeta3 induces 12-HETE production within 5 min and pretreatment of tumor cells with select lipoxygenase inhibitior, Baicalein, prevents the increase in serine phosphorylation. Confocal microscopy of adherent tumor cells demonstrated rearrangement of actin filaments upon alphaIIbbeta3 ligation paralleled by downregulation of p125FAK and phoshotyrosine+ adhesion plaques and translocation of PKCalpha to stress fibers and cortical actin. PKC appears to be the major effector serine kinase of the alphaIIbbeta3-coupled signaling pathway, since pretreatment of tumor cells with a select PKC inhibitor, Calphostin C, prevents the ligation-induced serine phosphorylation. Previous studies have indicated a role for the 12-lipoxygenase-PKC signaling pathway in platelet aggregation as well as tumor invasion, therefore the involvement of this cascade in the signaling of the ectopic alphaIIbbeta3 integrin may partially explain its role in tumor progression.

Role of the basement membrane in tumor cell dormancy and cytotoxic resistance

OBJECTIVES AND METHODS

Tumor dormancy and resistance to cytotoxic agents are key limiting events in the treatment of malignant diseases. To determine whether both are influenced by the extracellular milieu in which tumors reside, HT1080 human fibrosarcoma, MCF-7 breast carcinoma and OSCORT osteosarcoma cell proliferation, viability, apoptosis and cytoreductive-treatment-induced death were investigated in the presence or absence of extracellular matrix (ECM).

RESULTS

ECM-adherent, but not plastic-adherent HT1080 cells formed a multicellular network accompanied by reduced proliferation and lowered DNA synthetic capacity. The number of cells in S-phase was dramatically reduced. Viable cells entered a state of dormancy reminiscent of that observed in the step of metastasis after extravasation, i.e. prior to the initiation of progressive growth. Such ECM-induced dormancy could be reversed by plating cells on plastic, but only after a 48-hour lag period. No difference was indicated in clonogenicity of HT1080 cells originated from plastic or ECM gel. However, the cells released from ECM gel showed significantly reduced migration ability. The resistance of anchored cells against cytotoxic damage was increased by ECM gel. Examination of cytoreductive treatment revealed that ECM adherence at the time of injury is partially protective, a property which was also moderately apparent when injured cells were transferred to the basement membrane.

CONCLUSIONS

Taken together, these results suggest that the ECM plays a key role in tumor dormancy and cytotoxic resistance, both explorable at the molecular level using our in vitro model system.

Origin and structural evolution of the early proliferating oval cells in rat liver

We have analyzed the histological changes in rat liver after 2-acetylaminofluorene (AAF) administration. The data demonstrate that AAF-induced oval cells were preferentially generated by proliferation of the terminal biliary ductules that we suggest constitute the primary hepatic stem cell niche. The oval cells formed ductular structures, representing an extension of the canals of Hering. This histological organization provides continuous bile drainage of the hepatocytes and uninterrupted blood flow in the sinusoids. The oval cell ductules are surrounded by a continuous basement membrane that is intermittently disrupted by processes of stellate cells that form direct cell-cell contact with the oval cells. Although both AAF treatment and bile duct ligation results in proliferation of biliary epithelial cells, the mechanism(s) responsible for the proliferation of the biliary epithelium seems to differ in the two models. In contrast to the biliary proliferation stimulated by bile ligation, AAF-induced oval cell proliferation as well as the capacity of these cells to differentiate into hepatocytes, bile epithelial cells and possibly other cell lineages can be blocked by administration of dexamethasone.

Autocrine motility factor (neuroleukin, phosphohexose isomerase) induces cell movement through 12-lipoxygenase-dependent tyrosine phosphorylation and serine dephosphorylation events

Autocrine motility factor (AMF) is one of the motility cytokines regulating tumor cell migration, therefore identification of the signaling pathway coupled with it has critical importance. Previous studies revealed several elements of this pathway predominated by lipoxygenase-PKC activations but the role for tyrosine kinases remained questionable. Motility cytokines frequently have mitogenic effect as well, producing activation of overlapping signaling pathways therefore we have used B16a melanoma cells as models where AMF has exclusive motility effect. Our studies revealed that in B16a cells AMF initiated rapid (1-5 min) activation of the protein tyrosine kinase (PTK) cascade inducing phosphorylation of 179, 125, 95 and 40/37 kD proteins which was mediated by upstream cyclo- and lipoxygenases. The phosphorylated proteins were localized to the cortical actin-stress fiber attachment zones in situ by confocal microscopy. On the other hand, AMF receptor activation induced significant decrease in overall serine-phosphorylation level of cellular proteins accompanied by serine phosphorylation of 200, 90, 78 and 65 kd proteins. The decrease in serine phosphorylation was independent of PTKs, PKC as well as cyclo- and lipoxygenases. However, AMF induced robust translocation of PKCalpha to the stress fibers and cortical actin suggesting a critical role for this kinase in the generation of the motility signal. Based on the significant decrease in serine phosphorylation after AMF stimulus in B16a cells we postulated the involvement of putative serine/threonine phosphatase(s) upstream lipoxygenase and activation of the protein tyrosine kinase cascade downstream cyclo- and lipoxygenase(s) in the previously identified autocrine motility signal.

Reconstitution of liver mass via cellular hypertrophy in the rat

The liver has an extremely effective regenerative capacity. When 70% of a rat liver is removed by surgery, the liver mass regrows in 7 to 10 days by the compensatory hyperplasia of the remnant part. In case of damage to the surviving hepatocytes, the facultative stem-cell compartment is activated and the liver regenerates by means of oval-cell proliferation/differentiation. In the present study, we demonstrate that when both hepatocyte proliferation and stem-cell activation were prevented by dexamethasone (Dex) administration, the liver mass was restored in the absence of DNA synthesis. The restoration of the liver was accomplished by the preferential enlargement/hypertrophy of the periportal hepatocytes. A similar response was observed when cell proliferation was arrested by 5-fluorouracil (FU) following partial hepatectomy. Therefore, the hepatocytic hypertrophy appears to provide an alternative mechanism of liver-mass restoration. This hypertrophic condition of the liver is not stable, because following the withdrawal of Dex, the enlarged hepatocytes entered in the cell cycle and the normal liver structure and DNA content was re-established.

Beta-arrestin- and dynamin-dependent endocytosis of the AT1 angiotensin receptor

The major mechanism of agonist-induced internalization of G protein-coupled receptors (GPCRs) is beta-arrestin- and dynamin-dependent endocytosis via clathrin-coated vesicles. However, recent reports have suggested that some GPCRs, exemplified by the AT1 angiotensin receptor expressed in human embryonic kidney (HEK) 293 cells, are internalized by a beta-arrestin- and dynamin-independent mechanism, and possibly via a clathrin-independent pathway. In this study, agonist-induced endocytosis of the rat AT1A receptor expressed in Chinese hamster ovary (CHO) cells was abolished by clathrin depletion during treatment with hyperosmotic sucrose and was unaffected by inhibition of endocytosis via caveolae with filipin. In addition, internalized fluorescein-conjugated angiotensin II appeared in endosomes, as demonstrated by colocalization with transferrin. Overexpression of beta-arrestin1(V53D) and beta-arrestin1(1-349) exerted dominant negative inhibitory effects on the endocytosis of radioiodinated angiotensin II in CHO cells. GTPase-deficient (K44A) mutant forms of dynamin-1 and dynamin-2, and a pleckstrin homology domain-mutant (K535A) dynamin-2 with impaired phosphoinositide binding, also inhibited the endocytosis of AT(1) receptors in CHO cells. Similar results were obtained in COS-7 and HEK 293 cells. Confocal microscopy using fluorescein-conjugated angiotensin II showed that overexpression of dynamin-1(K44A) and dynamin-2(K44A) isoforms likewise inhibited agonist-induced AT1 receptor endocytosis in CHO cells. Studies on the angiotensin II concentration-dependence of AT1 receptor endocytosis showed that at higher agonist concentrations its rate constant was reduced and the inhibitory effects of dominant negative dynamin constructs were abolished. These data demonstrate the importance of beta-arrestin- and dynamin-dependent endocytosis of the AT1 receptor via clathrin-coated vesicles at physiological angiotensin II concentrations.

Angiogenesis-dependent diseases and angiogenesis therapy

The discovery of the molecular mechanisms of physiological vasculogenesis and pathological angiogenesis helped to recognize two classes of diseases: one where the therapeutic angiogenesis can repair the tissue damages (arteriosclerosis, myocardial infarction, limb ischemia) and the other one where inhibition of pathological angiogenesis can cure the disease or delay its progression (retinopathies, benign and malignant angiogenic tumors, progression of malignant tumors). Although there are an exponentially growing number of new synthetic molecules characterized mainly by antiangiogenic properties, the discovery of a large battery of natural pro- and anti-angiogenic factors suggests that this may provide a more physiological approach to treat both class of angiogenesis-dependent diseases in the near future.

Antiproliferative efficacy of the somatostatin analogue TT-232 in human melanoma cells and tumours

BACKGROUND

TT-232, a somatostatin analogue, induces apoptosis in various tumours. The aim of our study was to characterise its effect on human melanoma cells and tumours.

MATERIALS AND METHODS

Proliferation of seven melanoma cell lines was tested in vitro with the methylene blue test. D10 and 205 cells were also implanted into CB17-scid mice which received 30-150-750 micrograms/kg/day of TT-232 or saline. Animals with 205 cells received twice-daily subcutaneous injections whereas animals with D10 cells were treated with osmotic mini-pumps. In addition, TT-232 metabolites were generated with tissue homogenates and tested in vitro.

RESULTS

TT-232 strongly inhibited proliferation of all cell lines in vitro and tumour growth in vivo. Two out of 8 animals (30-150 micrograms/kg) in the 205 model and one out of 8(150 micrograms/kg) in the D10 model became completely tumour-free at the 11th and 9th day of treatment, respectively. TT-232 was degraded only by liver homogenate whilst its metabolite had no antiproliferative effect in vitro.

CONCLUSIONS

TT-232 is a promising drug candidate for melanoma.

Syndecan-1-dependent homotypic cell adhesion in HT58 lymphoma cells

OBJECTIVES

Many cellular functions are controlled by cell-cell and cell-matrix interactions. It has recently been found that syndecans, transmembrane heparan sulphate (HS) proteoglycans, can act as receptors or co-receptors and modulate cell adhesion. Our aim was to study the role of syndecan-1 in the aggregation of human lymphoma cells, and to investigate its effect on cell survival.

METHODS

Immunocytochemistry, confocal laser scanning microscopy, flow cytometry and aggregation/reaggregation bio-assays were used on HT58, BL41/95 and Raji lymphoma cell lines.

RESULTS

Bio-assays showed that the aggregation of HT58 cells was inhibited by heparin, HS, removal of the HS chain and binding of the anti-syndecan-1 monoclonal antibody. In the search for a counter-receptor of syndecan-1, several adhesion molecules were tested, but none of them proved to be the adhesion partner. In the case of heparitinase/trypsin digestion with long-term inhibition of HS synthesis (sodium chlorate treatment), the inhibited aggregation was accompanied by cell cycle arrest and the induction of apoptosis.

CONCLUSIONS

The results obtained showed that surface syndecan-1 expression contributes to homotypic adhesion. In addition, HS chains, including those on syndecan-1, take part in the regulation of cell proliferation and active cell death in HT58 lymphoma cells.

Tenascin expression in primary and recurrent breast carcinomas and the effect of tenascin on breast tumor cell cultures

Tenascin is generally classified as an anti-adhesive protein. Many cells do not adhere to tenascin or if they adhere they do not spread. In this study we analysed the stromal expression of tenascin-C in primary, second primary and recurrent breast carcinomas and the ability of tenascin-C to stimulate the focal adhesion plaques in MDA-MB-435 breast carcinoma cell line. To assess the tenascin-C expression formalin-fixed, paraffin-embedded specimens of 20 specially selected breast carcinomas and their recurrences (14) or a second primary breast cancer of the same patient (6) were examined with immunohistochemical methods. We also studied the effect of tenascin-C on focal adhesion plaques added to MDA-MB-435 breast carcinoma cell line. During a median 2,9-year patient follow up 14 local recurrences and 6-second primary breast carcinomas developed in the 20 patients. In 3 cases a second recurrence occurred. The presence of tenascin in tumor cells, in the proliferating and some normal ducts, near to the tumor cell nests, in the stroma and in ductal carcinoma in situ component of the invasive carcinoma may suggest the role of tenascin played in tumor cell migration. Soluble tenascin added to the cell culture had minimal or no effect on focal adhesion plaques. Tenascin only seems not to be of prognostic value in predicting the local recurrence of breast cancer.

[The effect of trace elements--especially zinc--on metastasizing of Lewis lung tumor]

The effect of a widely used trace element preparation (Béres-Drop Plus, BDP) on the liver metastasis forming potential of 3LL-HH tumor was studied. The daily, oral administration of BDP caused a decrease in the number of liver metastases, irrespective of the presence or absence of the primary spleen tumor. It is suggested, that the zinc component of BDP is responsible, at least partly--for the inhibitory action.

MSC, a new benzoquinone-containing natural product with antimetastatic effect

An orally applicable fermentation product of wheat germ containing 0.04% substituted benzoquinone (MSC) has been invented by Hungarian chemists under the trade name of AVEMAR. Oral administration (3 g/kg body weight) of MSC enhances blastic transformation of splenic lymphocytes in mice. The same treatment shortens the survival time of skin grafts in a co-isogenic mouse skin transplantation model, pointing to the immune-reconstructive effect of MSC. A highly significant antimetastatic effect of MSC has been observed in three metastasis models (3LL-HH, B16, HCR-25). The antimetastatic effect of MSC--besides the immune-reconstitution--may also be due to its cell adhesion inhibitory, cell proliferation inhibitory, apoptosis enhancing, and antioxidant characteristics, also observed in our in vitro experiments. It is even more noteworthy that combined treatment with MSC and one of the following antineoplastic agents (5-FU and DTIC)--both in wide use in every day clinical practice--exhibited a significantly enhanced antimetastatic effect in appropriate metastasis models (established from C38 mouse colon carcinoma and B16 mouse melanoma respectively) as compared to the effect elicited by any component of these therapeutic compositions (MSC + 5-FU and MSC + DTIC) administered alone. The results show that the fermented wheat germ extract (MSC) has more than an additive effect and synergistically enhanced the metastasis inhibitory effect of both antineoplastic agents studied till now. It is also worthy of mention that the synchronous treatment with MSC profoundly decreased the toxic side effects of the applied antineoplastic agents (decreased weight loss etc). Based on the biological effects of MSC--shown to be non-toxic by subacute toxicology studies--this product may be used as an adjuvant in the therapy of malignant neoplasia and other diseases caused by or following immune-deficiency.

Syndecan-1 (CD138) expression in human non-Hodgkin lymphomas

Syndecan-1, an important transmembrane heparan sulphate proteoglycan is expressed in distinct stages of differentiation of normal lymphoid cells: in pre-B cells and Ig-producing plasma cells; however, its normal function, or presence in lymphoid malignancies, is still largely unknown. The expression of syndecan-1 (CD138) was studied in 57 human non-Hodgkin lymphomas using immunocytochemistry and immunohistochemistry. Positive expression of syndecan-1 was found in the plasma cells in chronic lymphoblastic leukaemia (B-CLL) cases, in different plasmocytoid lymphomas as well as in myeloma. All normal and malignant Tcells, or CD5+ cells other than B-CLL proved to be negative. These results strongly suggest that syndecan-1 expression is a characteristic phenotypic marker for B-CLL and lymphoplasmocytoid lymphomas and could be used for diagnostic purposes.

[A new benzoquinone-containing antimetastatic product]

An orally applicable fermentation product of wheat germ containing 0.04% substituted benzoquinone (MSC) was invented by Hungarian chemists under the trade--name of AVEMAR. The following biological effects of this product were observed. Oral administration (3 g/kg body weight) of MSC enhances blastic transformation of splenic lymphocytes of mice. The same treatment shortens the survival time of skin grafts in co-isogenic mouse skin transplantation model, which points to immune-reconstructive effect of MSC. Highly significant anti-metastatic effect of MSC was observed in three metastasis models (3LL-HH, B16, HCR-25). The antimetastatic activity of MSC--besides the immune reconstitution--may also due to the cell-adhesion inhibitory, cell proliferation inhibitory, apoptosis-enhancing and antioxidant effects, which were also observed in our in vitro experiments. Based on the biological effects of MSC--which is non-toxic, according to subacute toxicology studies--this product may be used as an adjuvant in the therapy of malignant neoplasia and other diseases caused by or following immunedeprivation.

Methamphetamine-induced neurotoxicity in BALB/c, DBA/2N and C57BL/6N mice

Repeated administration of methamphetamine (METH; 2 and 4 mg/kg, s.c. four times every 2 h) caused hyperthermia and a dose-dependent depletion of striatal dopamine levels 3 days after the METH-treatment in both BALB/cAnNCrj (BALB) and DBA/2NCrj (DBA) mice, but these responses were lower in C57BL/6NCrj (C57BL) mice. An acute decrease of striatal dopamine levels 30 min after the last injection of METH (4 mg/kg) was observed in both BALB and DBA mice, while an increase in dopamine was observed in C57BL mice. Striatal 3-methoxytyramine levels were drastically increased in both DBA and C57BL mice after this same treatment. Moreover, pretreatment with the superoxide dismutase inhibitor, diethyldithiocarbamate (200 mg/kg, i.p.) exacerbated the METH (4 mg/kg)-induced striatal dopamine-depletion in BALB mice. In addition, pretreatment with an inhibitor of poly(ADP-ribose) polymerase, benzamide (160 mg/kg, s.c.), significantly attenuated the METH (4 mg/kg)-induced striatal dopamine depletion in both BALB and DBA mice. These results suggest that both BALB and DBA mice possess a higher sensitivity to the METH-induced striatal dopaminergic neurotoxicity compared to C57BL mice. In addition, the striatal dopaminergic neurons of BALB mice may be more vulnerable to METH-induced oxidative stress as compared to that in C57BL mice.

Oral administration of a trace element preparation and zinc inhibit liver metastasis of 3LL-HH murine tumor cells

A trace element preparation (TEP-Beres Drops Plus) was given to liver metastasizing 3LL-HH tumor bearing mice in the presence and after the removal of the primary spleen tumor. In both models when TEP was provided daily and orally in a dose range of 100-5,000 microgram/kg, the number of liver metastasis decreased at an end-point of day 14 and TEP also had inhibitory effect on the primary tumor. The antitumor action proved to be dependent on tumor burden. There was no change in body weight, size distribution of metastases and in the life span of mice. Zn++ could be one of the antimetastatic components among the trace elements. This is the first report on the antimetastatic effect of trace elements in an experimental tumor model.

Effect of Avemar and Avemar + vitamin C on tumor growth and metastasis in experimental animals

Because of the observed immunostimulatory actions of a new fermented wheat germ extract--with standardized benzoquinone composition--we have investigated the eventual tumor growth- and metastasis-inhibiting effects of this preparation (Avemar) applied alone or in combination with vitamin C. Tumor models of different origin [a highly metastatic variant of the Lewis lung carcinoma (3LL-HH), B16 melanoma, a rat nephroblastoma (RWT-M) and a human colon carcinoma xenograft (HCR25)]--kept in artificially immunosuppressed mice were applied. The metastasis-inhibiting effects of the treatments have been studied both in the presence and in the absence (following surgical removal) of the transplanted primary tumors. Combined treatments with Avemar and vitamin C--administered synchronously--profoundly inhibited the metastasis formation in all the applied tumor models while, treatments with vitamin C alone did not exert such an inhibiting effect on the metastasizing process. The degree of the observed metastasis inhibition in certain models was significant, while in others--although it was meaningful--did not prove to be significant. It is noteworthy that treatment with Avemar alone in certain models exerted a more pronounced inhibiting effect on metastasis formation than the synchronous combined treatment with Avemar and vitamin C. Furthermore, if the time schedule of the combined treatment was changed (vitamin C--instead of being administered synchronously--was given one hour after the treatments with Avemar), the vitamin C rather decreased the metastasis inhibiting effect of Avemar. It should be mentioned however, that in the case of rat nephroblastoma, a different response was observed: while, in the case of synchronous combination significant inhibition of metastasis formation was observed, treatment with Avemar alone did not produce metastasis-inhibition. It is noteworthy that in this model the metastasis-inhibiting effect of the synchronous combination treatment proved to be even more pronounced if Avemar was administered in a 100 times smaller dose than its regularly applied dosage. Treatment with Avemar and vitamin C--administered in combination or separately--in the majority of experimental models (with the exception of rat nephroblastoma) did not inhibit the growth of the primary tumors. It is reasonable, therefore, to suppose that in the observed metastasis-inhibiting effect the eventual proliferation inhibiting effect of these remedies does not play an important role. According to the results of other experiments--carried out in our laboratory in parallel with those described here--Avemar proved to have a meaningful immunostimulatory effect. It might therefore be suggested that the observed metastasis-inhibiting effect of this preparation may be mainly due to its immunostimulatory properties. The possible therapeutic benefits of Avemar and Avemar plus vitamin C are also discussed.

Expression and secretion of neuroleukin/phosphohexose isomerase/maturation factor as autocrine motility factor by tumor cells

The results obtained from fragmented protein microsequencing have suggested that autocrine motility factor (AMF), a tumor-secreted Mr 55,000 cytokine that regulates cell motility in vitro as well as invasion and metastasis in vivo, is the neuroleukin (NLK)/phosphohexose isomerase (PHI)/maturation factor (MF) polypeptide. Here, we cloned, sequenced, and studied the expression, secretion, and distribution of AMF/NLK/PHI/MF in neoplastic and their normal counterpart cells. Although both normal and neoplastic cells express the gene product, overexpression associated with selective secretion of the protein was observed only in tumor cells. The cDNA sequences of AMF/NLK/PHI/MF found in both human cancer and normal cells were found to be identical, suggesting that its secretion by neoplastic cells is independent of mutation or alternative splicing. Immunohistochemical visualization has depicted AMF/NLK/PHI/MF to be localized into tubular-like vesicles, diffusely distributed throughout the cytoplasm and not colocalized with any particular cytoskeletal network. Confocal microscopic imaging had shown a partial colocalization between AMF and its receptor (Mr 78,000 glycoprotein), especially on the malignant cell surface periphery. The results suggest that extracellular AMF activity may be a result of the product of intracellular cleavage of a precursor polypeptide, which is overexpressed and selectively secreted through a nonclassical secretory mechanism by neoplastic cells.

Role of alphaII(b)beta3 integrin in prostate cancer metastasis

BACKGROUND

Integrins participate in cell-cell and cell-matrix interactions. In this study we determined whether alphaII(b)beta3 integrin is involved in metastasis of human prostate adenocarcinoma cells.

METHODS

Prostate adenocarcinoma PC-3 and DU-145 cell lines express alphaII(b)beta3. Northern blotting, 5'-RACE, and immunofluorescent localization confirmed expression of alphaIIb integrin in prostate adenocarcinoma cells. We used orthotopic/ectopic site of implantation and lung colonization assays in SCID mice to determine whether alphaII(b)beta3 participates in metastatasis of tumor cells.

RESULTS

Immunofluorescent localization of alphaIIb integrin in fibronectin-adherent DU-145 and PC-3 cells is remarkably different. In DU-145 cells the integrin localizes to focal contact sites, whereas it is predominantly intracellular in PC-3 cells. Both tumor cell lines are tumorigenic when implanted subcutaneously or intraprostatically in SCID mice, but only DU-145 cells injected intraprostatically metastasize. Flow cytometry with a mAb directed to alphaII(b)beta3 revealed higher expression of alphaII(b)beta3 in DU-145 tumor cell suspensions isolated from the prostate when compared to DU-145 tumor cells from the subcutis. Function-blocking mAbs to alphaII(b)beta3 inhibit lung colonization of tail vein-injected DU-145 cells.

CONCLUSIONS

Altogether, the data suggest that alphaII(b)beta3 integrin participates in the metastatic progression of prostatic adenocarcinoma.

Autocrine motility factor and the extracellular matrix. I. Coordinate regulation of melanoma cell adhesion, spreading and migration involves focal contact reorganization

Cellular interactions with the extracellular matrix are complex and are involved in numerous biological processes. These interactions may be modulated by cytokines such as tumor cell autocrine motility factor, a secreted molecule that regulates cellular growth and migration by a receptor-mediated pathway. In this report we provide evidence suggesting that high- and low-metastatic K1735 melanoma cells coordinate their attachment, spreading and migratory responses to autocrine motility factor and the extracellular substratum through alterations in focal adhesion plaque architecture that are dependent on both inherent cellular metastatic phenotype and the composition of the supporting matrix. Thus, since activation of the autocrine motility factor receptor has previously been shown to enhance the experimental metastasis of the high- but not the low-metastatic K1735 cells, differences in melanoma cell malignancy in this system may be due in part to a coordinated interplay between cytokine-mediated responses and extracellular matrix-directed regulation of cellular adhesion, spreading and motility.

Autocrine motility factor and the extracellular matrix. II. Degradation or remodeling of substratum components directs the motile response of tumor cells

Autocrine motility factor is a tumor-secreted cytokine which regulates cellular growth and motility by a receptor-mediated pathway. In the accompanying report (Part I of II), it was demonstrated that high (K1735-M1) and low (K1735-C1.11) metastatic murine melanoma cells display distinct adhesion and spreading characteristics which correlate with their differential spontaneous and stimulated migrations on the extracellular matrix components fibronectin, laminin and collagen IV. These parameters were further related to discrete profiles of focal adhesion plaque integrity and reorganization. Here we describe unique migration patterns observed in these murine melanoma cells which reflect differences in degradation and/or remodeling of the cellular substratum. These profiles of matrix interaction were influenced distinctly by autocrine motility factor and dictated by both substrate composition and cellular phenotype. Since activation of the autocrine motility factor receptor stimulates invasion of a reconstituted basement membrane and enhances experimental metastasis by high- but not low-metastatic K1735 cells, differences in the invasive phenotypes of these cells may be due in part to their differential responses to external stimuli coupled with internal propensities toward either matrix degradation and migration (high-metastatic cells) or matrix remodeling and stasis (low-metastatic cells).

Current concepts of tumor-induced angiogenesis

Tumor induced angiogenesis is responsible for the nutrition of the growing tumor and can also increase the probability of hematogenous tumor dissemination. Data obtained from morphological analysis of tumor angiogenesis can contribute to the development of new anti-angiogenic therapies. Based on in vitro and in vivo observations several models of angiogenesis were introduced, explaining the mechanism of lumen formation and the timing of basement membrane depositon. (1) Lumen is formed either by cell body curving or by fusion of intracellular vacuoles of nonpolarized endothelial cells. New basement membrane is deposited after lumen formation. (2) Slit-like lumen is immediately formed by migrating polarized endothelial cells. Basement membrane is continuously deposited during endothelial cell migration, only cellular processes of the endothelial cell migrating on the tip of the growing capillary are free of deposited basement membrane material. (3) Development of transluminal bridges in larger vessels a process called intussusceptive growth leads to the division of the vessels. These models, however, describe angiogenesis in tissues rich in connective tissue. Different processes of angiogenesis take place in organs such as liver, lungs, adrenals, which are the most frequent sites of metastasis having high vessel density without sufficient space for capillary sprouting. In the case of liver metastases of Lewis lung carcinoma the proliferation of endothelial cells was elicited only by direct contact between tumor and endothelial cells, leading to the development of large convoluted vessels inside the metastases. These vessels were continuous with the sinusoidal system, suggesting that these metastases have dual blood supply. This observation, among others, is in contrast to the generally accepted view that liver tumors have arterial blood supply. The increasing number of data demonstrating the dual or venous blood supply of liver metastases should be taken into consideration in the therapy of liver metastasis.

Tumor cell motility and metastasis : Autocrine motility factor as an example of ecto/exoenzyme cytokines

Cellular locomotion plays a critical role in such normal processes as embryonic development, tissue segregation, as well as the infiltration of fibroblasts and vascular cells during wound repair and the inflammatory responses of the adult immune system. During tumor invasion and metastasis the processes of cell migration achieve dire significance. Disruption of normal homeostatic mechanisms to benefit the survival of the individual tumor cell is a common theme discovered during the characterization of factors once thought to be tumor-specific. One such molecule, tumor cell autocrine motility factor, was so described and has only recently been identified as a normal protein involved in intracellular glycolysis as well as implicated as an extracellular effector of normal cell functions including survival of certain populations of neurons. This molecule represents a member of the newly emerging family of intracellular enzymes whose disparate functions as extracellular mediators of cellular responses defines a new class of ecto/exoenzymes which play a role in normal cellular processes and are inappropriately utilized by tumor cells to elicit new survival strategies.

Role of sinusoidal heparan sulfate proteoglycan in liver metastasis formation

Previous studies have indicated that the predominant sites of tumor cell extravasation in the liver are the sinusoidal vessels, where tumor cells contact the sinusoidal endothelium and the subendothelial extracellular matrix containing the basic components of the basement membrane. We studied the role of sinusoidal extracellular matrix in metastatsis formation by 3LL-HH murine tumor cells selected for their preferential liver colonization. 3LL-HH tumor cells did not efficiently adhere to cryosections of the liver, but they recognized the sinusoids and vessel walls. Pre-treatment of the mice with polyclonal anti-basement membrane antibodies [anti-laminin, anti-fibronectin and anti-heparan sulfate proteoglycan (HSPG)] significantly modulated the organ distribution of tumor cell colonies following intracardial injection: all 3 antibodies inhibited kidney colonization; anti-laminin and anti-fibronectin antibodies inhibited lung colonization; and only anti-HSPG antibody inhibited liver colonization. In several organs such as the heart, stomach, pancreas and bladder, anti-basement membrane antibody treatment did not alter the process of colonization. Immunofluorescence studies showed that anti-HSPG antibody recognized the basement membranes of sinusoids and blood vessels. Our data suggest a specific involvement of sinusoidal HSPG in the liver colonization of 3LL-HH cells.

Tumor autocrine motility factor responses are mediated through cell contact and focal adhesion rearrangement in the absence of new tyrosine phosphorylation in metastatic cells

Autocrine motility factor (AMF) is a tumor-secreted cytokine that acts as a motogen as well as a mitogen via a receptor-mediated signaling pathway(s). Expression of the AMF receptor (AMF-R) in normal cells is regulated by cell contact whereas in transformed cells AMF-R is constitutively expressed irrespective of cell density. Here we have analyzed the regulation of AMF-R expression in a BALB/c angiosarcoma tumor system that allows investigation of cellular characteristics associated with tumor progression. The metastatic cell variant (A31-M) displayed a higher rate of unstimulated motility and responded to tumor-derived AMF locomotory stimulus as compared with the nonmetastatic cell variants (A31-TR and A31-TU) and, although a similar level of receptor expression was detected in cellular extracts from subconfluent cultures of these sublines, surface localization differed and cell contact down-regulated AMF-R expression in the normal but not the transformed cell counterparts. AMF promoted marked rearrangement of focal adhesion plaque proteins in the AMF migration-responsive cells exclusively. Reorganization of vinculin after AMF stimulation was paralleled by morphological redistribution of tyrosine-phosphorylated proteins and the tyrosine kinase pp125FAK in the migration-responsive cells; however, we did not observe a concomitant change in the pp125FAK phosphorylation state or the general level of cellular tyrosine phosphorylation in response to treatment, suggesting that the induction of cellular migration by AMF is independent of tyrosine phosphorylation events at the focal contacts and may therefore represent a novel pathway of cytokine-induced migration regulation.

The antimetabolite Tiazofurin (TR) inhibits glycoconjugate biosynthesis and invasiveness of tumour cells

We investigated the effect of Tiazofurin (TR-2-beta-D-furanosylthiazole-4-carbamide) on tumour cell invasion using metastatic 3LL-HH murine lung carcinoma and HT168-M1 human melanoma as experimental models. TR pretreatment of 3LL-HH cells, in a dose range of 15-60 microM, caused inhibition of cell proliferation, adhesion to plastic and extracellular matrix proteins. The TR-induced altered matrix interactions of 3LL-HH cells were reflected in decreased migration through matrix-covered filters. Analysis of the expression of certain invasion markers indicated that TR suppressed the expression of alpha v beta 3 integrin and MMP2 metalloproteinase. Biochemical studies indicated that 24 h 60 microM TR treatment of 3LL-HH cells inhibited glycosylation of a wide range of glycoproteins with the most pronounced effect on proteoglycans. TR pretreatment of 3LL-HH tumour cells resulted in the loss of lung colonisation potential in vivo. Furthermore, in vivo TR treatment inhibited the formation of liver metastases of 3LL-HH murine carcinoma. TR treatment also induced inhibition of integrin and MMP2 expression, migration and liver colonisation of the human melanoma HT168-M1 cell line. Since the TR concentration which inhibited various cellular functions was much lower for cell adhesion and lung colonisation than for cell proliferation, we suggest that the predominant effect of TR is the inhibition of metastasis in these model systems. We also suggest that both the effect of TR on tumour cell proliferation and on extracellular matrix interaction contribute to its remarkable antimetastatic potential in vivo.

Small bowel obstruction caused by a medication bezoar: report of a case

We report herein the rare case of a 26-year-old woman who developed a small-bowel obstruction caused by a medication "bezoar" or enterolith, following the long-term ingestion of magnesium oxide cathartics for constipation. Medication bezoars resulting from laxatives or cathartics have rarely been reported and we were only able to find two other such cases in the literature.

Modulation of heparan-sulphate/chondroitin-sulphate ratio by glycosaminoglycan biosynthesis inhibitors affects liver metastatic potential of tumor cells

Previous data have indicated that the proteoglycan (PG) pattern is different on tumor cells with different liver metastatic potential. We selected "conventional" glycosaminoglycan (GAG) biosynthesis inhibitors, beta-D-xyloside (BX), 2-deoxy-D-glucose (2-DG), ethane-l-hydroxy-l,l-diphosphonate (ETDP) and the newly discovered 5-hexyl-2-deoxyuridine (HUdR), to modulate PGs on highly metastatic/liver-specific 3LL-HH murine carcinoma and HT168 human melanoma cells and to influence their liver colonization potential. These compounds all induced remarkable changes in GAG biosynthesis, but to varying degrees: glucosamine labelling was affected mainly by 2-DG, and HUdR and sulphation by BX and HUdR. Furthermore, the ratio of heparan sulphate/chondroitin sulphate (HS/CS) of PGs was increased by ETDP and decreased after treatment by HUdR. In addition to changes in PG metabolism, tumor-cell proliferation and adhesion to fibronectin were affected; BX and 2-DG stimulated cell proliferation and adhesion, while HUdR inhibited both proliferation and adhesion. Most interestingly, HUdR, the most effective inhibitor of HS/HSPG, depressed the formation of liver colonies, while ETDP, the most effective inhibitor of CS/CSPG, stimulated the appearance of liver colonies. These observations indicated that, at least in these experimental systems, tumor cells with a high HS/CS ratio are more likely to form liver metastases; consequently, anti-HS agents could also be anti-metastatic.

Metastasizing rat nephroblastoma. A rodent Wilms' tumour model

In newborn F344 rats, immunosuppressed with antithymocyte sera and xenografted with various human tumours (lymphomas and melanomas), regular development of nephroblastomas was observed. Transplantation experiments and chromosome analysis proved the rat origin of the tumours. The histological appearance of these rat nephroblastomas closely resemble that of the human Wilms' tumour, in which three basic components: blastema, stroma and immature epithelium can be distinguished. With serial subcutaneous-, lung-subcutaneous transplantations in immunocompetent newborn animals a spontaneously metastatic line to the lung was selected. In adult hosts, lung metastasis occurred only following orthotopic (subrenal capsule) implantation. The histogenesis and the morphological features of this rat nephroblastoma and its metastases are described.

Morphological aspects of angiogenesis in experimental liver metastases

In this work we describe the process of angiogenesis in liver metastases of high- and low-metastatic 3LL mouse carcinoma lines. Fourteen days after intrasplenic inoculation of the tumor lines, two types of metastases were observed; a sinusoidal type, containing large convoluted vessels and devoid of immunohistochemically detectable basement membrane, and a portal type, located in the vicinity of portal tracts, characterized by numerous small vessels, and staining positively for basement membrane components. After intrasplenic inoculation of the high-metastatic tumor cells (portal route) only 18.2% of the metastases were portal type, whereas when the tumor cells were injected into the left ventricle (arterial route), a significantly higher percentage of the metastases (33.2%) proved to be portal type. Detailed analysis of the process of angiogenesis were performed only concerning the main, sinusoidal type metastases. After intrasplenic inoculation of tumor cells, vascularization of tumor colonies started on day 6 by the appearance of intratumoral sinusoids lined by endothelial cells. These sinusoids were directly connected with liver sinusoids. Afterward (11 to 14 days), large convoluted vessels developed within the metastases, in which tumor globules protruded. These globules were covered by factor VIII-related antigen-positive endothelial cells. The functioning vascular nature of these vessels were proven by supravital staining with Hoechst 33342 dye and by bromodeoxyuridine labeling. The first event of the angiogenesis in sinusoids and veins seemed to be the separation of the endothelial cells from their basement membrane, demonstrated by electron microscopic immunohistochemistry (laminin, fibronectin). This process elicited vigorous proliferation of the matrix-deprived endothelial cells, shown by the increased bromodeoxyuridine labeling index and by the increased number of endothelial cell nuclei per mm vessel length. Morphometric analysis of the sinusoids in the perimetastatic zone (up to 100 mu) and in the normal liver parenchyma showed neither dilatation of the vessels nor sprouting of new vessels in the former region. There was no difference in the neovascularization of the liver metastases of the high- and low-metastatic carcinoma lines. The dominant type of angiogenesis in liver metastases can be determined by the unique basement membrane architecture of the liver and by the high affinity of 3LL tumor cells to the endothelial side of basement membrane during invasion.

First steps of tumor-related angiogenesis

We present morphological data of the early steps of tumor-induced angiogenesis and show the distribution of the three main components of the basal lamina (BL), laminin, collagen IV, and fibronectin during these early processes. Tumor cells of a line of BSp73 AS a nonmetastasizing tumor isolated from a pancreatic adenocarcinoma were injected subcutaneously into the back of BDX rats. Two days after tumor inoculation, the BL of the dilated mother vessels around the whole circumference of the vessel has either disappeared, become fragmented, or developed several successive layers. By immunoelectron microscopy, we demonstrate that the fragmented and multilayered BL is strongly stained for laminin and collagen IV but less strongly for fibronectin. Around the surface of the dilated mother vessels which are free of any detectable BL material (by electron microscopy standards), we can see accumulation of all three components in the connective tissue. Simultaneously with the alteration of the BL, the proliferation of the endothelial cells (EC) and the pericytes and the migration of the EC from the wall of the mother vessel have started. EC migration begins in two different ways. Either one EC migrates from the wall of the mother vessel into the surrounding connective tissue, or two or more EC form nearly parallel processes toward the connective tissue. The tips of these processes are connected by intracellular junctions. Around the cellular protrusions of these cells material of the BL deposited into the nearby connective tissue can be observed neither by conventional nor by immunoelectron microscopy. During the outgrowth and migration, the EC remain in contact via junctions with the EC of the original vessel. When migration during which the EC retain their polarization continues, a slit-like lumen forms immediately between the migrating EC. This lumen always remains in direct connection with the lumen of the mother vessel. It is sealed at its border by intercellular junctions. Such junctional complexes can develop a length (in sections) of several hundred micrometers. A BL detectable in the electron microscope can neither be found around the tip of the migrating EC nor around young capillaries not yet surrounded by pericytes. By immunoelectron microscopy, however, only the cellular protrusions at the tip of migrating EC are free of deposited material of the BL. The basal surface of longer (new) capillaries is covered by a continuous layer of amorphous material.(ABSTRACT TRUNCATED AT 400 WORDS)

Selection and characterization of human melanoma lines with different liver-colonizing capacity

Two human melanoma lines with low (HT168) and high (HT168-MI) liver metastatic capacity in immunosuppressed mice were selected in vivo from the A2058 cell line. After i.v. injection of the 2 tumor lines there was no significant difference either in the number of lung colonies or in the frequency and tissue distribution of extrapulmonary tumor deposits. These findings suggest that the selection in the spleen-liver system did not result in an overall increase in the metastatic potential of the melanoma cells, but rather that it represented an organ-preferential selection. The HT168-MI cells did not acquire an increased growth rate in vitro or in vivo, suggesting that other phenotypic alterations are responsible for the enhanced metastatic capacity. The 2 tumor lines were characterized by similar expression of HLA-A,B,C, transferrin receptor and melanoma-associated proteoglycan antigen. HT168 contained more NGF receptor, while HLA-DR appeared only on HT168-MI cells. This human metastasis model could be useful in studying the mechanisms of liver metastasis formation, as well as in revealing possible new targets of antimetastatic therapy.

Ultrastructure of invasion in different tissue types by Lewis lung tumour variants

Ultrastructural studies on the interactions of low and highly metastatic 3LL tumour lines with the basement membranes (BMs) of capillaries, veins, muscles, nerves and adipose tissue were performed by injecting tumour cells into the foot pad of mice. Haematogenous dissemination is the principle route of metastasis formation. Cells from the highly metastatic line were able to penetrate the blood vessels more efficiently than those from the low metastatic line. This difference was mainly due to a more pronounced diapedesis-like activity of the 3LL-HH cells, and partly to the altered intratumour vessel architecture in the highly metastatic tumour line. There was no difference between the two lines in the ultrastructure and frequency of invasion of nerves and adipose tissue BMs. However, in the highly metastatic line an extremely efficient penetration of muscle cell BM was observed. These results provide further evidence that the interaction of tumour cells with the BMs of different tissue types is one of the main determinants in local and distant dissemination.

[Effect of AS-4370 on gastric emptying--double-blind clinical pharmacological study]

The effect of AS-4370 given in single doses of 2.5, 5 and 10 mg on gastric emptying was investigated using 99mTc-DTPA in healthy volunteers in the placebocontrolled double-blind crossover design. There was no difference in percent activity throughout the period of measurement between AS-4370 2.5 mg and placebo. The percent activity decreased after administration of 5 and 10 mg of AS-4370 in comparison with placebo: the decrease was found during the period from 10 to 18 minutes after start of recording at 5 mg and from 8 to 18 minutes after start of recording at 10 mg. These results demonstrated that AS-4370 at these dose levels apparently accelerated gastric emptying. The analysis of the half emptying time by the crossover method showed that only the time effect was found at 2.5 mg, whereas the half emptying time was obviously shortened at 5 and 10 mg. There was no difference between 5 mg and 10 mg. There was no finding that might warrant a caution in terms of safety. In conclusion, AS-4370 did not affect gastric emptying at 2.5 mg but apparently accelerated gastric emptying at 5 and 10 mg in healthy volunteers.

Glycosaminoglycans as novel target in antitumor therapy

Considering the importance of intercellular contacts in the metastasis of malignant tumours drug action on glycosaminoglycan production as one of the underlying mechanisms in metastasis was investigated. 5-hexyl-2-deoxyuridine/HUdR/was shown to inhibit the conversion of glucosamine to UDP-sugars. Consequently various glycoconjugates were affected, especially the synthesis of heparan sulfate was reduced. It is noteworthy that HUdR inhibited the synthesis of glycosaminoglycans in tumour cells with high metastatic capacity. The biological consequence of the alterations in glycosaminoglycan production was studied on measuring HUdR action on cell surface markers, microinvasion and tumour metastasis in experimental systems. It was concluded that HUdR has remarkable antimetastatic activity which by all probability is due to the inhibition of heparane sulfate synthesis.

[Effects of cisapride on gastric emptying]

To evaluate the effects of cisapride on gastric emptying, gastric emptying was measured in six healthy volunteers using radioisotopic techniques which were established three areas of interest, i.e. the whole stomach, the proximal stomach and the antrum. Following results were obtained. 1. At the half emptying times, cisapride induced a more rapid gastric emptying than did placebo in 5 of 6 volunteers. 2. By analyzing gastric emptying curves obtained from three areas of interest, it was suggested that cisapride enhanced the transfer of gastric contents from the proximal stomach to the antrum together with the antral emptying, so that gastric emptying was accelerated.

Effectiveness of tiazofurin (NSC 286193) in treating disseminated tumor cells and micrometastases in mice

The authors studied the metastasis-inhibiting effect of various dosages of tiazofurin in mice inoculated with a low (LLT) and a highly (LLT-HH) metastatic variant of the Lewis lung carcinoma. The tumor cells were inoculated intravenously (lung colony assay), intramuscularly (muscle-lung metastasis model), and intrasplenically (spleen-liver metastasis model), respectively. In the lung colony assay the tiazofurin proved to be curative. In the muscle-lung and the spleen-liver model the tiazofurin treatment, started after the removal of the parent tumor, drastically decreased the number of metastases in both model systems and brought about a significant prolongation of the survival time in the spleen-liver model. Authors suggest that tiazofurin as one of the most promising candidates for metastasis prevention and inhibition in human beings, too.

Demonstration of the organ preference of liver selected 'high metastatic' Lewis lung tumor cell line

The experimental metastasis patterns of 'low metastatic' Lewis lung tumor (LLT) and liver selected 'high metastatic' LLT-HH were studied following their arterial dissemination. In previous reports it was shown that both tumor lines develop metastases only in the first encountered organ. Here the liver preference of the liver selected cell line is demonstrated. The model of two LLT cell lines can provide experimental evidence for both the 'mechanical' and 'seed and soil' theories of metastasis formation, depending on the site of tumor cell injection.

Two human melanoma xenografts with different metastatic capacity and glycosaminoglycan pattern

Two human melanoma xenografts were compared with respect to their in vivo growth and metastatic potentials as well as glycosaminoglycan patterns. The less differentiated HT 168 tumor showed faster growth at primary sites and a more pronounced capacity for metastasis into the liver. Although chondroitin sulfate was the dominant glycosaminoglycan subtype in both tumors, the more invasive xenograft had a higher heparan sulfate/chondroitin sulfate (HS/CS) ratio. We suggest that tumor progression is influenced by this ratio in this human melanoma system.

Endothelialization of embolized tumor cells during metastasis formation

The reaction of the endothelial barrier to tumor cell extravasation has been studied using electron microscopy. The model system was pulmonary metastases produced by intravenous injection of B16-F10 melanoma cells. A striking difference was observed in the behavior of the endothelial lining of arterioles versus that of capillaries. In capillaries, partial retraction of endothelial cells took place following the attachment of tumor cells. The tumor cells then immediately attached to the basement membrane and the basolateral surface of the retracted endothelial cells. The endothelial cells extended to cover the tumor cells prior to complete extravasation. In the arterioles, on the other hand, endothelial retraction did not occur following tumor cell attachment. Instead the attached tumor cell emboli became encompassed by endothelial cells, outgrowing from the intact endothelial lining of the arteriole. Owing to the proliferation of the tumor cells, tumor colonies encompassed by endothelial cells expanded within the lumen. When these intravascular growths completely filled the lumen, the tumor cells extravasated from the vessel only after the original endothelial layer became mechanically disrupted and the tumor cells thereby came into contact with the basement membrane.