A novel, nuclear pore-associated, widely distributed molecule overexpressed in oncogenesis and development.

Nuclear pore complexes are large, elaborate macromolecular structures that mediate the bidirectional nucleocytoplasmic traffic. In vertebrates, nuclear pore complexes comprise 50 to 100 proteins termed nucleoporins (Nup). An 88-kd nucleoporin (Nup88) has been recently cloned and characterized, and found to be associated in a dynamic subcomplex with the oncogenic nucleoporin CAN/Nup 214. We have produced a polyclonal antiserum to Nup88, and found that it immunoreacts convincingly in conventional tissue sections of 214 samples of malignant tumors of many types. All carcinomas were stained irrespective of site or line of differentiation; the majority of cases reacted strongly and extensively. In situ carcinomas and highly dysplastic epithelia were similarly reactive. Samples of malignant mesotheliomas, gliomas, sarcomas, and lymphoreticular tumors were also stained. Substantial reactions were also found in certain fetal tissues. Focal reactions were noted in some reactive-proliferative processes. Most benign epithelial and mesenchymal tumors and hyperplasias, and normal adult tissues reacted weakly and sporadically or not at all. Immunoblot analysis of selected samples strongly corroborated those findings. If further substantiated, our findings indicate that Nup88 could be regarded as a selective yet broadly based proliferation marker of potential significance in the histological evaluation and diagnosis of malignant transformation. Its ready applicability on conventional paraffin sections and on cytological preparations may broaden its clinical and investigative significance.

Fine-needle aspiration of extranodal and extramedullary hematopoietic malignancies.

There is relatively little information concerning the use of fine-needle aspiration (FNA) to diagnose extranodal and extramedullary hematopoietic malignancies. Seventy-one such cases diagnosed by FNA form the basis of this study. Seventy-one cases of FNAs performed between 1988 and 1998 on extranodal and extramedullary hematopoietic malignancies were reviewed in order to evaluate the usefulness of this technique in diagnosing these entities as well as to assess patterns of relapse. There were 45 male and 26 female patients ranging in age from 29-86 years (mean, 68 years). Sixty-six patients had a previous history of a hematopoietic malignancy. Aspirates from 65 of these patients were consistent with the patient's known primary. One aspirate of a paravertebral mass from a multiple myeloma patient showed extramedullary hematopoiesis. The remaining five aspirates were cases of multiple myeloma that first presented as soft tissue masses. The most common malignancies were lymphoma: 52 cases (73%), 48 large cell lymphomas, four mixed small and large cell lymphoma; followed by multiple myeloma: 12 cases (17%); leukemia: four cases (5.4%); Hodgkin disease: two cases (2.8%); and one case of extramedullary hematopoiesis. The aspirate sites were soft tissue: 23 cases (32%); bone: 17 cases (24%); kidney: 14 cases (20%); liver: 11 cases (15%); lung: three cases (4%); adrenal: two cases (3%); and eye: one case. The interval between primary diagnosis and FNA was 1-36 months (mean, 13 months). In conclusion, 98% of the aspirates were neoplastic in patients with a known history of hematopoietic malignancies. The most common site of involvement was soft tissue in 23 (32%) cases. In five patients with multiple myeloma, the FNA diagnosis prompted a work-up to find the primary site of involvement. FNA is a useful technique in assessing extranodal and extramedullary hematopoietic malignancies.

Nitric oxide (NO), methylation and TIMP-1 expression in BL6 melanoma cells transfected with MHC class I genes.

We have previously found that transfection of BL6-8 melanoma cells with the H-2K, but not H-2D/L genes resulted in loss of their metastatic ability that was associated with decrease in their invasiveness and up-regulation of TIMP-1 expression. In the present study using the methylation-specific PCR (MSP) we found that lack of TIMP-1 expression in BL6-8 is associated with methylation in the TIMP-1 5' regulatory area. In the H-2Kb transfected CL8-1 melanoma cells up-regulation of TIMP-1 was in parallel with loss of TIMP-1 gene methylation. Treatment of BL6-8 with 5-azacytidine or with an inhibitor of histone deacetylase trichostatin A resulted in up-regulation of TIMP-1 expression. These results indicate that methylation and histone deacetylation play an important role in transcription repression of TIMP-1 in BL6 melanoma cells. Some data showed that nitric oxide (NO) could affect methylation and expression of various gene. Therefore we analyzed NO production in B16 melanoma cell lines with different expression of TIMP-1. We have found that B16F10 and BL6-8 melanoma cells do not express TIMP-1 and do not produce nitric oxide (NO) even after stimulation with IFN-gamma and LPS. However, BL6-8 cells transfected with H-2Kb or H-2Kd, but not H-2Dd or H-2Ld gene expressed TIMP-1 and produced NO constitutevely. NO production in these cells was further stimulated by IFN-gamma and LPS. Northern blot analysis showed that expression of iNOS was paralleled with TIMP-1 expression in the tested melanoma cells. However, NO produced by SNAP or inhibition of NO production by NMA did not affect TIMP-1 expression in the tested melanoma cells. Thus, TIMP-1 expression and NO production in BL6 melanoma cells transfected with MHC class I gene coincides but it remains unclear whether NO is responsible for the change in TIMP-1 methylation and expression.

Nitric-oxide production by murine mammary adenocarcinoma cells promotes tumor-cell invasiveness.

The role of nitric oxide (NO) in tumor biology remains controversial and poorly understood. While a few reports indicate that the presence of NO in tumor cells or their micro-environment is detrimental for tumor-cell survival, and consequently their metastatic ability, a large body of data suggests that NO promotes tumor progression. The purpose of this study was to identify the source of NO in the spontaneously metastasizing C3-L5 murine mammary-adenocarcinoma model, the role of tumor-derived NO in tumor-cell invasiveness, and the mechanisms underlying the invasion-stimulating effects of tumor-derived NO. The source of NO was established by immunocytochemical localization of NO synthase (NOS) enzymes in C3-L5 cells in vitro and transplanted tumors in vivo. An in vitro transwell Matrigel invasion assay was used to test the invasiveness of C3-L5 cells in the presence or the absence of NO blocking agents or iNOS inducers (IFN-gamma and LPS). The mechanisms underlying the invasion-stimulating effects of tumor-derived NO were examined by measuring mRNA expression of matrix metalloproteinases (MMP)-2 and -9, and tissue inhibitors of metalloproteinases (TIMP) 1, 2 and 3 in C3-L5 cells in various experimental conditions. Results showed that C3-L5 cells expressed high level of eNOS protein in vitro, and in vivo, both in primary and in metastatic tumors. C3-L5 cells also expressed iNOS mRNA and protein when cultured in the presence of IFN-gamma and LPS. Constitutively produced NO promoted tumor-cell invasiveness in vitro by down-regulating TIMP 2 and TIMP 3. In addition, there was up-regulation of MMP-2, when extra NO was induced by IFN-gamma and LPS. In conclusion, NO produced by C3-L5 cells promoted tumor-cell invasiveness by altering the balance between MMP-2 and its inhibitors TIMP-2 and 3. Thus, our earlier observations of anti-tumor and anti-metastatic effects of NO inhibitors in vivo in this tumor model can be explained, at least in part, by reduced tumor-cell invasiveness.

Role of nitric oxide in tumor progression: lessons from experimental tumors.

Nitric oxide (NO), a potent biological mediator, plays a key role in physiological as well as pathological processes, including inflammation and cancer. The role of NO in tumor biology remains incompletely understood. While a few reports indicate that the presence of NO in tumor cells or their microenvironment is detrimental to tumor cell survival and consequently their metastatic ability, a large body of clinical and experimental data suggest a promoting role of NO in tumor progression and metastasis. We suggest that tumor cells capable of very high levels of NO production die in vivo, and those producing or exposed to lower levels of NO, or capable of resisting NO-mediated injury undergo a clonal selection because of their survival advantage; they also utilize certain NO-mediated mechanisms for promotion of growth, invasion and metastasis. The possible mechanism(s) are: (a) a stimulatory effect on tumor cell invasiveness, (b) a promotion of tumor angiogenesis and blood flow in the tumor neovasculature, and (c) a suppression of host anti-tumor defense. In this review, we discuss these mechanisms on the basis of data derived from experimental models, in particular, a mouse mammary tumor model in which the expression of eNOS by tumor cells is positively correlated with invasive and metastatic abilities. Tumor-derived NO was shown to promote tumor cell invasiveness and angiogenesis. The invasion-stimulating effects of NO were due to an upregulation of matrix metalloproteases and a downregulation of their natural inhibitors. Treatment of tumor-bearing mice with NO-blocking agents reduced the growth and vascularity of primary tumors and their spontaneous metastases. We propose that selected NO-blocking drugs may be useful in treating certain human cancers either as single agents or as a part of combination therapies.

Role of nitric oxide in IL-2 therapy-induced capillary leak syndrome.

Nitric oxide (NO) is a potent short-lived and short range bioactive molecule, which plays a key role in physiological and pathological processes including inflammation and cancer. Detrimental effects of excessive NO production during septic shock have been well recognized. We tested the hypothesis that 'capillary leak syndrome' following systemic interleukin-2 (IL-2) therapy resulted from a cascade of events leading to the induction of NO which, directly or indirectly, injured capillaries and caused fluid leakage. Our results provided the first direct evidence that the induction of active NO synthase (NOS) leading to the overproduction of NO is instrumental in IL-2-induced capillary leakage in mice and that successful blocking of this overproduction with chronic oral administration of NOS inhibitors can mitigate this leakage without interfering with the beneficial antitumor effects of IL-2 therapy. NO blocking agents can, in fact, improve IL-2-induced antitumor effector cell activation, as well as tumor regression. In our studies, NO blocking agents alone reduced the growth and metastasis of a murine mammary carcinoma, at least in part, by mitigating the invasion and angiogenesis-stimulating role of tumor-derived NO. Thus, NOS inhibitors may be useful in treating certain tumors and serve as valuable adjuncts to systemic IL-2 based immunotherapy of cancer and infectious diseases.

Effects of chronic indomethacin therapy on the development and progression of spontaneous mammary tumors in C3H/HEJ mice.

The present study was designed to test the hypothesis that endogenous prostaglandin E (PGE) promotes the development, growth and metastasis of spontaneous mammary tumors in C3H/HeJ female retired breeder mice. The effect of chronic oral indomethacin (indo) therapy starting at 6 months of age was tested on these parameters as well as on animal survival, in comparison with control mice placed on 0.2% ethanol in drinking water for up to 25 months of age. Indo treatment delayed the initial (up to 27 weeks) development of primary tumors by 11-12 weeks; however, the subsequent rate of tumor appearance was unaffected (totaling 82% in indo-treated vs. 90% in controls by 25 months of age). Spontaneous regression of primary tumors (26% in controls) increased 2-fold (53%) with indo therapy. While the apparent reduction in the growth rate of primary tumors and the overall prolongation of animal survival were not significant, the lifespan of mice bearing multiple tumors was significantly prolonged by therapy. There was also a 2-fold reduction in the incidence of lung metastases in mice bearing detectable primary tumors, and this was more pronounced during the earlier phase of tumor development. Positive immunostaining for cyclooxygenase-2 enzyme (indicative of the cellular source of PGE) was exhibited by tumor cells, stromal cells and macrophages within the primary tumors. Tumors in indo-treated mice exhibited histological evidence of increased differentiation (acinar architecture), significant tumor cell death, mononuclear cell infiltration and reduction in vascularity, indicating that the beneficial effects of indo were due to multiple mechanisms, including improved immune response and reduced angiogenesis.

The role of active inducible nitric oxide synthase expression in the pathogenesis of capillary leak syndrome resulting from interleukin-2 therapy in mice.

Previously, we showed that nitric oxide (NO) plays a major role in the pathogenesis of IL-2-induced capillary leak syndrome in healthy or mammary adenocarcinoma-bearing C3H/HeJ mice. NO synthase (NOS) inhibitors, such as NG-nitro-L-arginine methyl ester (L-NAME) reduced all the manifestations of IL-2-induced capillary leakage, without compromising the antitumor effects of IL-2. The present study was carried out on healthy C3H/HeJ mice subjected to one or two 4-day rounds of systemic IL-2 therapy with or without oral L-NAME therapy to: (a) identify the tissue source of NOS activity and NOS protein induced by IL-2 therapy; (b) identify histologically the nature of the structural damage to the lungs associated with IL-2 therapy-induced pulmonary edema; and (c) evaluate the effects of additional L-NAME therapy on the above-mentioned parameters. Results revealed that IL-2 therapy in healthy mice resulted in the expression of inducible NOS in numerous tissues including the endothelium and muscles of the anterior thoracic wall as well as splenic macrophages. One round of IL-2 therapy resulted in high levels of inducible NOS (iNOS) activity in the anterior thoracic wall accompanied by pleural effusion. After two rounds of IL-2 therapy, there was neither pleural effusion nor high iNOS activity in the thoracic wall. IL-2-induced pulmonary edema after one round of therapy correlated to both a significant rise in NO production measured in the serum and structural damage to the lungs and its capillaries. Addition of the NOS inhibitor L-NAME totally eradicated NOS activity but not necessarily iNOS expression. It also reduced IL-2-induced pulmonary edema and pleural effusion, restrained the rise in the levels of NO metabolites (nitrites and nitrates) in the serum and pleural effusion, and significantly restored the structural integrity of the lungs after one round of therapy. Thus, NOS inhibitors may be beneficial adjuncts to IL-2 therapy for cancer and infectious diseases.

Effects of N(G)-Nitro-L-arginine methyl ester, an inhibitor of nitric oxide synthesis, on IL-2-induced LAK cell generation in vivo and in vitro in healthy and tumor-bearing mice.

We had earlier shown that therapy with N(G)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide (NO) synthesis, had antitumor and antimetastatic effects in C3-L5 mammary adenocarcinoma-bearing mice. When combined with interleukin-2 (IL-2) therapy, L-NAME augmented antitumor effects of IL-2. In the present study, we tested whether the L-NAME effects were due, at least in part, to a potentiation of antitumor cytotoxicity of host effector cells. We examined the effects of L-NAME on IL-2-induced generation of antitumor cytotoxicity in vivo and in vitro in splenocytes of healthy and C3-L5 tumor-bearing C3H/HeJ mice, using 51Cr release assay. IL-2 treatment, in vivo or in vitro, markedly stimulated splenocyte tumoricidal activity against NK-sensitive (YAC-1) and -resistant (C3-L5) targets, accompanied with an increase in NO production measured in the serum or culture medium. Addition of L-NAME to IL-2 therapy blocked IL-2-induced NO production in vivo and improved IL-2-induced splenocyte cytotoxicity as well as tumor regression. Addition of L-NAME in vitro also reduced IL-2-induced NO production in the medium and enhanced IL-2 induced cytotoxicity of splenocytes of healthy but not tumor-bearing mice. These results reveal that IL-2-induced increase in NO production in vivo causes a suppression of LAK cell activation, which can be overcome by NO inhibition with L-NAME therapy. These findings, combined with our observation that L-NAME can mitigate IL-2 -induced capillary leakage in healthy and tumor-bearing mice, suggest that L-NAME could be a valuable adjunct to IL-2 therapy of cancer and infectious diseases.

NG-nitro-L-arginine methyl ester, an inhibitor of nitric oxide synthesis, ameliorates interleukin 2-induced capillary leakage and reduces tumour growth in adenocarcinoma-bearing mice.

We tested whether NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide (NO) synthesis, can prevent interleukin 2 (IL-2)-induced capillary leakage in tumour-bearing mice without compromising the therapeutic benefits of IL-2. C3H/HeJ female mice transplanted s.c. with 2.5 x 10(5) C3-L5 mammary carcinoma cells were treated with: nothing, IL-2 (ten injections of 15,000 Cetus units i.p. every 8 h), L-NAME (0.1, 0.5, or 1 mg ml-1 drinking water), IL-2 + L-NAME (0.1 or 0.5 or 1 mg ml-1 drinking water). Therapies were given in one round (IL-2, days 10-13; L-NAME, days 9-13) or in two rounds (IL-2, days 10-13 and 20-23; L-NAME, days 9-13 and days 19-23) after tumour transplantation. Capillary leakage was measured from the water contents of the pleural cavities, lungs, spleen and kidneys. Effects of the therapies on the primary tumour size and the number of spontaneous lung metastases were also recorded. NO production was measured as the nitrite + nitrate levels in the serum and in the pleural effusion. After the first round of therapies, addition of L-NAME significantly reduced IL-2-induced pulmonary oedema and water retention in the spleen in a dose-dependent manner. It also significantly reduced the IL-2-induced rise in NO levels in the serum and pleural fluid, but did not affect IL-2-induced pleural effusion or water retention in the kidney. At later stages of tumour growth (day 23), tumours themselves induced significant fluid retention in the lungs and the kidney, which was not aggravated further with the second round of IL-2 therapy. At this time, L-NAME therapy alone ameliorated tumour-induced pulmonary oedema. During both rounds of therapy different doses of L-NAME alone caused a reduction of primary tumour growth as well as spontaneous lung metastases, which improved further with the addition of IL-2. The combination therapy was at least as effective as IL-2 therapy. In summary, L-NAME had anti-tumour effects in vivo, reduced the severity of IL-2-induced capillary leakage in some organs and did not compromise anti-tumour efficacy of IL-2 therapy. Thus, L-NAME could be a valuable adjunct to IL-2-based cancer therapy.

Effects of N(g)-methyl-L-arginine, an inhibitor of nitric oxide synthesis, on interleukin-2-induced capillary leakage and antitumor responses in healthy and tumor-bearing mice.

We tested whether treatment with an inhibitor of nitric oxide synthesis (Ng-methyl-L-arginine, MeArg) can ameliorate interleukin-2(IL-2)-therapy-induced capillary leak syndrome in healthy or tumor-bearing mice without compromising the antitumor effects of IL-2 therapy. Healthy or C3-L5-mammary-adenocarcinoma-bearing C3H/HeJ mice were treated with one or two rounds of various doses of IL-2 (ten injections, i. p., every 8 h) or MeArg (ten injections s. c., every 8 h) or their combination. In an additional experiment, MeArg was given chronically in the drinking water, rather than s. c. to healthy mice subjected to one round of therapy as above. Mice were killed 1 h after their last IL-2 injection to measure the water content of the lungs and pleural cavities (markers of capillary leakage), NO production (given by NO2- and NO3- levels in the serum and pleural effusion), as well as the effect of therapies on the primary tumor size and number of spontaneous lung metastatic nodules. Results revealed that all doses of IL-2 (7500-35000 Cetus U/injection), as well as both rounds of IL-2 therapy, caused capillary leakage. However, no pleural effusion was seen after the second round in any of the IL-2-treated groups. MeArg therapy, given subcutaneously (5-20 mgkg(-1) injection(-1) in healthy and 20 mgkg(-1) injection(-1) in tumor-bearing mice), did not ameliorate IL-2-induced capillary leakage in either group of mice, and did not compromise antitumor effects of IL-2. However, subcutaneous MeArg therapy alone reduced the growth of the primary tumors, the occurrence of lung metastases and the amount of tumor-induced pulmonary edema. When MeArg therapy was given orally (1 mg/ml drinking water), a substantial drop in NO production, as well as reduction in capillary leakage was noted in IL-2-treated healthy mice. These findings suggest that NO inhibitors could be a valuable adjunct to IL-2 therapy of cancer and infectious diseases.

NG-nitro-L-arginine methyl ester, an inhibitor of nitric oxide synthesis, ameliorates interleukin-2-induced capillary leak syndrome in healthy mice.

We tested whether NG-nitro-L-arginine methyl ester (L-NAME), a potent inhibitor of NO synthesis, can prevent interleukin-2 (IL-2)-induced capillary leakage. Healthy C3H/HeJ female mice were treated with: nothing; IL-2 (10 injections; 35,000, 15,000, or 7,500 Cetus U i.p. every 8 h); IL-2 + L-NAME (0.01, 0.1, 0.5, and 1 mg/ml of drinking water starting 1 day before IL-2 therapy and ending with IL-2 therapy); or L-NAME alone. In the first series of experiments, mice were killed 1 h after last IL-2 injection to measure pleural effusion, and water content of the lungs, spleen, and kidney (markers of capillary leakage), as well as NO2- + NO3- levels in the serum and pleural effusion. In the two additional series, the survival of treated mice was followed. All doses of IL-2-induced capillary leak syndrome as indicated by pleural effusion, pulmonary edema, and fluid retention in the spleen and kidney. NO production was positively correlated with manifestation and severity of this syndrome. NO2- + NO3- levels in the pleural effusion were directly related to IL-2 dose, and L-NAME treatment reduced both the NO production and severity of capillary leakage, excepting fluid retention in the kidney. However, L-NAME therapy prevented IL-2-induced mortality only when combined with a middle range IL-2 dose (15,000 U/injection). In summary, oral L-NAME therapy effectively prevented IL-2-induced capillary leakage in healthy mice, suggesting its potential value as a supplement in IL-2-based immunotherapy of cancer and infectious diseases.