Chemokine receptors in advanced breast cancer: differential expression in metastatic disease sites with diagnostic and therapeutic implications.

BACKGROUND: We investigated the expression of CXCR4, CCR7, estrogen receptor (ER), progesterone receptor (PR) and HER2-neu in human metastatic breast cancers to determine whether these biological biomarkers were preferentially expressed in any organ-specific metastases. MATERIALS AND METHODS: CXCR4, CCR7, ER, PR and HER2-neu expression levels were evaluated by immunohistochemical staining using paraffin-embedded tissue sections of metastatic breast cancers (n = 41) obtained by either diagnostic biopsy or surgical resection. RESULTS: The metastatic sites included the following: bone (n = 15), brain (n = 14), lung (n = 6), liver (n = 2), and omental metastases (n = 2). CXCR4 was expressed in 41% of cases, CCR7 expression was demonstrated in 10%, and HER2-neu overexpression was present in 27%. CXCR4 was more likely to be expressed in bone metastases than visceral metastases (67% versus 26%, P = 0.020). Visceral sites demonstrated a lower rate of CXCR4 positivity (33% and 23%, respectively, for lung and brain metastases). Similarly, CCR7 was more likely to be found in bone metastases than visceral sites (27% versus 0%, P = 0.037). CONCLUSIONS: These results indicate that CXCR4 can contribute to the homing of breast cancer cells to the bone. This finding might have important clinical implications since patients with metastatic bone disease may achieve the highest benefit from a CXCR4-targeted therapy.

Innervation of the hamster Harderian gland.

Harderian glands of male and female hamsters have nerve endings associated with the secretory cells, myoepithelial cells, and the blood vessels. The nerve endings adjacent to the myoepithelial cells also have myoneural junctions.

Correlation of tumor growth inhibitory activity of macrophages exposed to adriamycin and adriamycin sensitivity of the target tumor cells.

Variant cell lines of the murine fibrosarcoma UV-2237, selected for doxorubicin [adriamycin (ADM)] resistance, were used to study the tumoricidal activity of macrophages that had been exposed to ADM. Free ADM (0.01-1 microgram/ml) was cytotoxic to the sensitive UV-2237M parent and to the partially sensitive UV-2237M-revertant cell lines, whereas the ADM-resistant UV-2237M ADMR line was unaffected by these levels of ADM. Macrophages harvested from the peritoneal cavities of mice given ip injections of 10 mg ADM/kg body weight 1 day or 4 days previously inhibited proliferation of the 3 cell lines, an effect that was directly correlated to the degree of ADM sensitivity of each cell line. Macrophages exposed in vitro to ADM (from 0.01 to 1 microgram/ml) inhibited the growth of, and eventually were cytolytic to, the parent and the revertant cell lines; these ADM-exposed macrophages did not affect the UV-2237M-ADMR cell line. The correlation between the antitumor effects of macrophages exposed to ADM and the ADM susceptibility of tumor cells suggests that ADM-exposed macrophages exert their effect by the release or transfer of the stored drug.

Quantitative fluorescent microassay for identification of antiproliferative compounds.

A reproducible and convenient microassay was developed by us to measure the antiproliferative activity of biological materials and anticancer drugs. The assay involved the labeling of target cells after their incubation with anticancer agents with the fluorescent vital dye hydroethidine at a dose of 28 micrograms/ml for 30 minutes. Once internalized into live cells, hydroethidine is dehydrogenated to ethidium, which then intercalates into DNA. Hydroethidine labeled the cells uniformly. The cells were lysed with detergent, and the relative fluorescence of this dye was monitored in a microfluorimeter at the speed of 30 seconds per 96-well plate. Because this assay is accurate and reproducible, does not present problems of disposal of labeling agents, and is extremely rapid, it should prove very useful for the screening of many potential anticancer agents with antiproliferative activity.

Development of a model of chronic lymphocytic leukemia in inbred strain 2 guinea pigs.

A new transplantable leukemia (KSL) of unknown etiology that arose in a female Sewall-Wright strain 2 guinea pig is described. KSL cells morphologically resembled medium to large lymphocytes, displayed surface Ia antigen and receptors for complement and for the Fc portion of immunoglobulin, and synthesized surface immunoglobulin (IgM). These characteristics suggest a leukemia of B-lymphocyte origin. KSL cells were shown to be sensitive in vivo to both cyclophosphamide and 1,3-bis(2-chloroethyl)-1-nitrosourea; however, neither drug effectively prevented eventual recurrence of the disease. KSL leukemia was also shown to be distinct from another guinea pig lymphatic leukemia (L2C) with respect to cell morphology, antigenicity, and in vivo growth rate. In this last respect, KSL appeared more closely related to the chronic lymphocytic leukemias. Thus KSL is the first chronic lymphocytic leukemia in the guinea pig to be characterized; it is also the only guinea pig model of lymphatic leukemia that is distinct from L2C leukemia currently available for study.

Influence of organ environment on extracellular matrix degradative activity and metastasis of human colon carcinoma cells.

Orthotopic implantation of human colon carcinoma cells is useful for studying the behavior of metastatic subpopulations. We observed that the parental line and variants of human colon carcinoma KM12 cells were all tumorigenic following implantation into the subcutis or cecal wall of BALB/c nude mice. Their ability to metastasize to distant organ sites varied, however, with the site of growth. Subcutaneous (SC) tumors did not produce visceral metastases, whereas cecal tumors metastasized to the regional mesenteric lymph nodes and to the liver. To examine the influence of organ environment on the extracellular matrix-degrading activity of the tumors, we inoculated human colon carcinoma cells into the subcutis or cecal wall and after 7 weeks isolated and cultured the tumors in serum-free medium. The conditioned media of SC tumors contained very low levels of type IV collagenase (gelatinase) and heparanase (heparan sulfate-specific endo-beta-D-glucuronidase), whereas the media of the cecal wall tumors contained high levels of both. Zymograms of the media revealed that the intracecal human colon carcinomas secreted more than three times the amount of latent and active forms of 92-kd type IV collagenase than did the SC tumors. Moreover, only the conditioned media of intracecal tumors contained latent and active forms of 64-kd type IV collagenase. Histochemical analysis using rabbit antiserum raised against the synthetic peptides of 72-kd procollagenase type IV showed type IV collagenase in the intracecal tumors; human colon carcinoma growing SC, however, were not stained significantly. These results suggest that factors in the organ environment may affect production and secretion of tumor extracellular matrix-degrading enzymes, and these factors may modify the metastatic behavior of human colon carcinoma cells in nude mice.

Organ-specific modulation of steady-state mdr gene expression and drug resistance in murine colon cancer cells.

BACKGROUND: The major cause of death from cancer is metastases that are resistant to conventional therapies. The resistance of metastatic tumor cells to chemotherapy can be caused by their intrinsic properties, such as increased expression of the mdr genes. PURPOSE: The purpose of our present study was to determine some of the mechanisms by which the organ microenvironment influences the response of tumor cells to chemotherapy. METHODS: Murine CT-26 colon cancer cells growing in continuous culture (parental cells) were harvested and injected subcutaneously into the lateral flank (to produce subcutaneous tumors) or the lateral tail vein (to produce experimental lung metastases) of 10 8-week-old syngeneic male BALB/c mice. Seven days after tumor-cell injection, the mice were given intravenous injections of either doxorubicin (10 mg/kg) or 0.9% NaCl (controls). This in vivo injection was repeated 7 days later. Mice with subcutaneous tumors and lung metastases were killed by cervical dislocation on day 21, and tumor samples from control mice were harvested and adapted to culture. The sensitivity of the cultured cells to doxorubicin and fluorouracil (5-FU) was determined at multiple time points. Levels of mdr-1 DNA were measured by slot-blot and Southern-blot analyses. mdr mRNA expression levels were measured by Northern-blot analysis using mdr-1- and mdr-3-specific hybridization probes, and P-glycoprotein level was determined by fluorescence-activated cell sorting using different monoclonal antibodies. RESULTS: Treatment with doxorubicin produced 80% growth inhibition of CT-26 subcutaneous tumors but had little effect on the number (and size) of experimental lung metastases. Collectively, the results suggest that the multidrug-resistant phenotype developed in CT-26 cells growing in the lung environment. Cultures established from lung metastases were initially resistant to doxorubicin (but not to 5-FU) and showed elevated expression of mdr-1 mRNA transcripts and P-glycoprotein. This resistance could be overcome by verapamil and disappeared after 21 days in culture. No mdr gene amplification was detected. The expression level of mdr-specific mRNA (predominance of mdr-1) and P-glycoprotein was directly associated with resistance to doxorubicin. CONCLUSIONS: Results of this study have demonstrated that the in vivo sensitivity of murine CT-26 colon carcinoma cells to doxorubicin depends on the organ environment. The organ environment can influence the P-glycoprotein-mediated multidrug-resistant phenotype in tumor cells, and the increased expression of P-glycoprotein is transient; once removed from the environment (lung), the cell's resistance reverts to that of the sensitive parent cells.

Expression of angiogenesis-related genes and progression of human ovarian carcinomas in nude mice.

BACKGROUND: By the time patients are diagnosed with ovarian carcinoma, peritoneal dissemination of the tumor often has occurred. The progressive growth and spread of ovarian carcinoma depend, in part, on the formation of an adequate blood supply. We determined whether the expression of genes that regulate distinct steps in angiogenesis (i.e., the formation of new blood vessels) was associated with the pattern and progressive growth of human ovarian carcinomas implanted in the peritoneal cavity of nude mice. METHODS: Five different human ovarian carcinomas were injected individually into the peritoneal cavity of female NCr-nu/nu nude mice. The expression of basic fibroblast growth factor, vascular endothelial growth factor/vascular permeability factor (VEGF/VPF), interleukin 8 (IL-8), and collagenase type IV (MMP-2 [matrix metalloproteinase-2] and MMP-9) was determined by northern blot analysis, in situ hybridization of messenger RNA, and immunohistochemical analysis. Blood vessel distribution and density, macrophage infiltration pattern, and stromal reaction were determined by immunohistochemical analysis with specific antibodies. RESULTS: Three of the carcinomas produced both solid lesions and ascitic tumors, whereas the remaining two produced only solid lesions. Two of the carcinomas produced rapidly progressive disease, two produced slow disease, and one produced intermediate disease. The formation of ascites was directly associated with expression of VEGF/ VPF, and survival was inversely associated with expression of IL-8. In rapidly growing tumors, the number of blood vessels was high throughout the lesion; in contrast, in slow-growing tumors, most vessels (and infiltrating macrophages) were located at the periphery. CONCLUSIONS: The expression of various genes that regulate angiogenesis in human ovarian carcinomas is associated with the pattern of the disease and its progression. Therefore, targeting specific genes that regulate angiogenesis could offer new approaches to the treatment of ovarian cancer.

Platelet-derived endothelial cell growth factor in human colon cancer angiogenesis: role of infiltrating cells.

BACKGROUND: Development of new blood vessels is essential for tumor growth and metastasis and depends on the production of angiogenic factors by tumor and/or infiltrating cells. We previously showed that vascular endothelial growth factor (VEGF) expression and vessel count correlate with metastasis in human colon cancer. Although most tumors with high vessel counts express high levels of VEGF, some do not. Recently, platelet-derived endothelial cell growth factor (PD-ECGF), another potent angiogenic factor, has been reported to be expressed in colon cancer. PURPOSE: In this study, we examined the role of PD-ECGF in colon cancer angiogenesis and whether PD-ECGF is derived from the tumor or infiltrating cells. METHODS: Immunostaining for PD-ECGF was performed on 96 colon cancer specimens, some of which were previously stained for VEGF and factor VIII, a marker that is specific for endothelial cells. Double staining was done by using antibodies to PD-ECGF and to CD68 (macrophage specific) or CD3 (lymphocyte specific) to confirm which infiltrating cells produce PD-ECGF. Northern blot analysis for PD-ECGF messenger RNA (mRNA) was performed on four colon cancer specimens and corresponding normal colon mucosae (same patients) and four human colon cancer cell lines (KM12SM, SW620, HT29, and NCI-H508) to determine whether colon cancer epithelium expresses PD-ECGF. RESULTS: Immunohistochemical analysis demonstrated that PD-ECGF was expressed in infiltrating cells in most of the colon cancer specimens (80 [83%] of 96) but rarely in tumor epithelium (five [5%] of 96). Double staining demonstrated that infiltrating cells staining positive for both PD-ECGF and CD68 were more predominant than those staining positive for both PD-ECGF and CD3. The intensity of staining for PD-ECGF in infiltrating cells correlated with vessel counts (Spearman's rank correlation coefficient (R) = .29; P = .004), but did not correlate with the intensity of VEGF staining (R = .176, P = .086) or metastasis (Mann-Whitney U test, P = .253). PD-ECGF staining intensity was higher in specimens with a high vessel count (> 50 at high magnification) and low VEGF-staining intensity (< or = 2+) than in specimens with a high vessel count (again, > 50) and high VEGF-staining intensity (3+). Northern blot analysis revealed that colon cancer specimens and normal mucosae expressed relatively high levels of PD-ECGF mRNA, whereas PD-ECGF mRNA transcripts were not detectable in colon cancer cell lines. CONCLUSIONS AND IMPLICATIONS: PD-ECGF expression in human colon cancer specimens is associated with vessel count and may be responsible for tumor vascularity in those tumors with low VEGF expression. Infiltrating cells expressing PD-ECGF may contribute to angiogenesis, thus providing an additional mechanism for tumor neovascularization.

Augmentation of antiproliferative activity of interferon alfa against human bladder tumor cell lines by encapsulation of interferon alfa within liposomes.

Present therapy for human bladder cancer includes the intravesical administration of antiproliferative agents, such as recombinant human interferon alfa (IFN-alpha). The administration of cytotoxic molecules encapsulated in liposomes could provide a more efficient method for such therapy. Therefore, we determined whether encapsulation of the recombinant human IFN-alpha hybrid BBDD within liposomes will produce antitumor effects against the human bladder cancer cell line 253J superior to those observed with free IFN-alpha. Adherent cells were cultured in medium alone, in medium containing different concentrations of IFN-alpha, or in medium containing multilamellar liposomes (phosphatidylcholine-phosphatidylserine at a molar ratio of 7:3) that encapsulated saline or IFN-alpha. Cell growth was determined 96-120 hours later. Additional control groups consisted of target cells cultured with free IFN-alpha or with IFN-alpha plus liposomes containing saline. Cytostasis mediated by free IFN-alpha alone or IFN-alpha in the presence of liposome-saline was identical and ranged from 0%-30% (10 IU/mL) to 45%-70% (1,000 IU/mL). Liposomes containing saline produced no effects. Liposome-encapsulated IFN-alpha produced significantly greater growth inhibition than free IFN-alpha: 40%-70% (10 IU/mL) and 80%-90% (1,000 IU/mL), respectively. Moreover, a 253J variant subline selected for resistance to free IFN-alpha was sensitive to IFN-alpha presented in liposomes. These data suggest that the encapsulation of antiproliferative agents such as IFN-alpha in liposomes can improve therapeutic results.

Correlation of growth capacity of human tumor cells in hard agarose with their in vivo proliferative capacity at specific metastatic sites.

The purpose of this study was to determine whether the degree of anchorage-independent growth of human tumor cells in increasing concentrations of agarose correlated with the capacity of the cells to produce experimental metastases in nude mice. Human melanoma, breast carcinoma, and colon carcinoma cells from parental lines and variants selected in vivo for metastasis and in vitro cloned lines were plated into medium containing 0.3%, 0.6%, 0.9%, or 1.2% of agarose. These cells were also injected into nude mice: intravenously for melanoma, into the mammary fat pad for breast carcinoma, and into the spleen for colon carcinoma. Production of tumor cell colonies in dense agarose (greater than 0.6%) correlated with production of experimental metastases in the lung (melanoma, breast carcinoma) or liver (colon carcinoma). We conclude that the degree of anchorage-independent growth of tumor cells can predict their biological behavior and metastatic potential in vivo. Thus, this technique may be useful for the isolation of metastatic cells from heterogeneous human neoplasms.

Carcinogenesis by nonmutagenic chemicals: early response of rat liver cells induced by methapyrilene.

Although methapyrilene (MP) produces hepatocellular carcinomas in rats, it does not elicit many of the cellular responses induced by other hepatocarcinogens. We have investigated the early changes induced in rat liver epithelial cell cultures by MP using morphological, cytochemical, and cytofluorometric techniques. Within 2 h of MP treatment, inclusion bodies which were stainable with lipid stains were observed in the cytoplasm. Ultrastructurally, they resembled lamellar bodies with alternating light and dark lamellae. These bodies were transient in nature, since they disappeared within 24 h of removal of MP. They were, however, retained in the cytoplasm as long as MP was present in the medium. Lamellar bodies appear to be induced in the presence of histamine H1 receptor-blocking agents, since methaphenilene and diphenhydramine produced this reaction, but cimetidine, an H2 antagonist, did not. Morphologically, mitochondria of control cells were long and rod-like, whereas they were short or bizarrely shaped in the MP-treated cells. Moreover, a quantitative increase was observed in the mitochondrial content of the treated cells, when intact liver cells vitally stained with Rhodamine 123 were analyzed with a fluorescence-activated cell sorter. A significant increase in binucleated cells was observed when liver cells were exposed for 10 to 12 days with MP. Collectively, these results suggest that MP might perturb the cytoskeletal elements leading to an alteration in the nuclear and mitochondrial makeup of rat liver cells.

Elevated expression of phosphatidylserine in the outer membrane leaflet of human tumor cells and recognition by activated human blood monocytes.

We determined whether the presence of phosphatidylserine (PS) in the outer membrane leaflet of human tumor cells correlated with their recognition by activated human monocytes. Three tumorigenic cell lines, A375 melanoma and A431 and Colo-16 carcinomas, and a normal human epidermal keratinocyte line (NHEK) were incubated with monocytes activated to the tumoricidal state by gamma-interferon and lipopolysaccharide. Activated human monocytes bound to and lysed all tumorigenic targets, while the nontumorigenic NHEK were neither bound nor killed. Semiquantitative analysis of PS in the outer leaflet of the cells revealed that the tumorigenic cells expressed 3-7-fold more PS than did the nontumorigenic NHEK. To determine whether enhanced PS expression on the tumor cells was responsible for their recognition by activated monocytes, NHEK were supplemented with exogenously supplied analogues of PS and phosphatidylcholine. PS-labeled NHEK but not phosphatidylcholine-labeled nor control NHEK bound to activated human monocytes. These results suggest a role for PS in monocyte recognition of tumor cells.

Expression of vascular endothelial growth factor and its receptor, KDR, correlates with vascularity, metastasis, and proliferation of human colon cancer.

We studied the correlation between expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and their receptors with vascularity, metastasis, and proliferative index of human colon cancers. Immunohistochemical analyses using antibodies against VEGF, bFGF, their receptors (KDR, flt-1, bek, and flg), factor VIII, and proliferating cell nuclear antigen were carried out on archival specimens of 52 human colon carcinomas and 10 adenomas. Vessels were quantitated by light microscopy (x200), and the intensity of staining for VEGF and bFGF was assessed on a scale of 0-3+. The presence or absence of immunostaining for KDR, flt-1, bek, and flg was evaluated in endothelial cells, and proliferation was determined by counting the number of proliferating cell nuclear antigen-positive cells per 500 tumor cells. Expression of VEGF and KDR was higher in metastatic than in nonmetastatic neoplasms and directly correlated with the extent of neovascularization and the degree of proliferation, whereas expression of bFGF, flt-1, bek, and flg did not differ among tumor types. Vessel counts were greater in metastatic tumors than in nonmetastatic tumors. These findings support the hypothesis that VEGF is an important angiogenic factor in primary and metastatic human colon cancer. VEGF expression and vessel counts may aid in predicting patients at risk for metastasis from colon cancer.

Expression of interleukin 8 correlates with the metastatic potential of human melanoma cells in nude mice.

We correlated the steady state transcription and protein secretion of interleukin 8 (IL-8) in 13 different human melanoma cell lines with their ability to grow and produce metastasis in nude mice. Highly metastatic cells expressed higher steady state levels of IL-8 mRNA transcripts than did low metastatic cells. In situ mRNA hybridization analyses confirmed the pattern of mRNA expression on a cellular level. Increased mRNA expression directly correlated with secretion of IL-8 protein as determined by enzyme-linked immunosorbent assay. Recombinant IL-8 stimulated the proliferation of low metastatic A375P cells in a dose-dependent manner, a stimulation that was abrogated by the use of a polyclonal antibody against IL-8. The data suggest that IL-8 can be an autocrine growth factor for human melanoma cells and that IL-8 is involved in melanoma metastasis.

Regulation of interleukin-8 expression in human melanoma cells by the organ environment.

The in vitro expression level of interleukin-8 (IL-8) correlates with the metastatic potential of human melanoma cells. The purpose of this study was to determine whether the expression level of IL-8 in human melanoma cells is influenced by the organ microenvironment. A375P cells, a low metastatic human melanoma, and A375SM cells, a highly metastatic variant, were injected into the subcutis (s.c.), spleen (to produce liver metastases), and lateral tail vein (to produce lung metastases) of athymic nude mice. Northern blot and immunohistochemical analyses determined that s.c. tumors, lung lesions, and liver lesions expressed high, intermediate, and low IL-8, mRNA, and protein, respectively. This differential regulation of IL-8 was not due to the size or density of the lesions or to selection of subpopulations of cells. We based this conclusion on the results of three experiments: (a) melanoma cell lines established in culture from in vivo-growing tumors exhibited similar levels of IL-8 mRNA transcripts; (b) in a crossover experiment, the level of IL-8 mRNA was always high in A375 tumors reestablished in the skin and low in the tumors reestablished in the liver, regardless of whether the melanoma cells had been first harvested from s.c. or liver tumors; and (c) A375 melanoma cells cocultured with human keratinocytes produced high levels of IL-8 protein, whereas A375 cells cocultured with highly differentiated human hepatoma cells produced decreased levels. When A375P cells were then incubated with cytokines associated with keratinocytes (IL-1 and interferon beta) or hepatocytes (transforming growth factor alpha or beta), IL-1 enhanced the production of IL-8 protein, whereas TGF-beta decreased its production. These data show that IL-8 expression in melanoma cells is modulated by local host factors.

Enhancement of murine tumor cell sensitivity to adriamycin by presentation of the drug in phosphatidylcholine-phosphatidylserine liposomes.

In vitro incubation of mouse UV-2237M fibrosarcoma cells with liposomes containing Adriamycin (ADR) produced significant cytotoxicity in drug-sensitive cells and in multidrug-resistant variants of this tumor. ADR was encapsulated in the aqueous space of multilamellar liposomes composed of phosphatidylcholine and phosphatidylserine. The preparation was stable in medium at 37 degrees C for up to 7 days. Free unencapsulated ADR produced cytostasis in parental ADR-sensitive cells but not in variant lines selected for resistance to the drug. In contrast, ADR encapsulated in multilamellar liposomes (MLV) produced high levels of cytostasis in both ADR-sensitive and ADR-resistant cells. The phospholipid composition of the MLV influenced the outcome of ADR-mediated cytostasis. ADR encapsulated in MLV consisting of only phosphatidylcholine did not produce cytostasis. Increasing the proportion of phosphatidylserine in the MLV increased the level of ADR-mediated cytotoxicity in cells resistant to free ADR. This effect was not due to simple modification of tumor cell surface by liposomes since ADR added to resistant cells together with liposomes containing buffer produced less cytostasis. The cytostasis of resistant cells by ADR in liposomes was not due to appreciable changes in the intracellular ADR concentration or localization within the cells because ADR-induced DNA cleavage was not found in ADR-resistant cells treated with cytostatic amounts of liposomal ADR. Whether the enhanced sensitivity of tumor cells to ADR was due to localized damage to the plasma membrane through a phosphatidylserine-mediated release of the drug to the cell surface is now under active investigation.

Blockade of nuclear factor-kappaB signaling inhibits angiogenesis and tumorigenicity of human ovarian cancer cells by suppressing expression of vascular endothelial growth factor and interleukin 8.

We determined whether blockade of nuclear factor (NF)-kappaB/relA activity in human ovarian cancer cells can suppress angiogenesis and growth in an orthotopic nude mouse model. The human ovarian cancer cells SKOV3ip.1 and HEY-A8 were transfected with a mutated IkappaBalpha (IkappaBalphaM), ie., resistant to phosphorylation and degradation, and hence blocks NF-kappaB activity. NF-kappaB signaling blockade significantly inhibited in vitro and in vivo expression of two major proangiogenic molecules, vascular endothelial growth factor and interleukin 8, in cultured cells and in cells implanted into the peritoneal cavity of nude mice. The decreased expression of vascular endothelial growth factor and interleukin 8 directly correlated with decreased tumorigenicity, decreased vascularization of lesions, decreased formation of malignant ascites, and prolonged survival of mice. These findings suggest that inhibition of NF-kappaB/relA activity in ovarian cancer cells can suppress angiogenesis and progressive growth.

A rapid colorimetric in situ messenger RNA hybridization technique for analysis of epidermal growth factor receptor in paraffin-embedded surgical specimens of human colon carcinomas.

We have developed a rapid colorimetric in situ mRNA hybridization procedure to analyze epidermal growth factor receptor (EGF-R) transcripts in paraffin-embedded surgical specimens of human colon carcinomas. This technique is based on the use of 24-base oligonucleotide probes labeled with 6 biotin molecules at the 3' end. mRNA integrity was verified using a hyperbiotinylated 30-residue-long deoxythymidylate oligonucleotide probe, and the specificity of the reaction was confirmed by using labeled EGF-R-specific sense and antisense probes. Avidin alkaline phosphatase detection and the capillary technology used in the Microprobe System allowed for completion of the procedure in under 5 h. The human A431 epidermoid carcinoma cells growing in culture and fixed with formalin as well as paraffin-embedded sections of this tumor growing s.c. in nude mice served as positive controls. In situ hybridization with antisense EGF-R oligonucleotide probes directly correlated with EGF-R mRNA and protein levels observed by Northern blot and immunohistochemistry, respectively. In situ hybridization of paraffin-embedded sections of primary human colon carcinoma and metastases from liver and lymph node revealed cell-specific staining with EGF-R antisense oligonucleotide probes that correlated directly with Northern blot and immunohistochemistry analyses. Since this rapid and sensitive in situ mRNA hybridization technique can be used in properly preserved paraffin-embedded tissue, it allows for retrospective analyses of human tumor specimens using archival material.

Therapy of spontaneous lung metastasis of murine renal adenocarcinoma by systemic administration of liposomes containing the macrophage activator CGP 31362.

Current therapies for renal cell carcinoma have been limited by the unresponsiveness of metastatic disease to conventional treatments. Although the use of biological response modifiers as adjuvant therapy has generally not been successful against disseminated disease, in situ activation of macrophages to a tumoricidal state by liposome-encapsulated immunomodulators has been shown to eradicate metastatic cancer in murine tumor models. We, therefore, designed experiments to evaluate the ability of a new macrophage activator, CGP 31362, a synthetic bacterial cell wall analogue, to cause regression of spontaneous lung metastases in mice whose primary renal adenocarcinoma was removed by nephrectomy. Delivery of the CGP 31362 to the lungs was accomplished by its encapsulation in multilamellar phospholipid liposomes (MLV-CGP 31362). Therapy with repeated i.v. injections of MLV-CGP 31362 significantly reduced the number of lung metastases in nephrectomized mice. Therapeutic efficacy of MLV-CGP 31362 was influenced by the encapsulation ratio of CGP 31362 to total phospholipid, the dose of injected liposomes, and the frequency of administration. Optimal therapy was achieved by combining the use of i.v. MLV-CGP 31362 with the s.c. injection of recombinant murine gamma interferon. Administration of MLV-CGP 31362 prior to removal of the primary tumor and continuing postoperatively was superior to postoperative therapy alone. Several lines of evidence indicate that in situ activation of macrophages was responsible for the therapeutic effects of MLV-CGP 31362: (a) macrophages harvested from the lungs of treated mice had significant tumoricidal activity against cultured renal carcinoma cells, (b) activated macrophages, as defined by the MRP-14 marker, were present in lung tumor nodules of treated mice but not untreated mice, and (c) the in situ activation of alveolar macrophages was consistent with the in vivo deposition of 60% of radiolabeled MLV-CGP 31362 liposomes in the lungs following i.v. injection. The results reported here represent the first in vivo evaluation of MLV-CGP 31362 and offer additional evidence that macrophage combination with therapies that reduce tumor burden.