Distinct antitumor properties of a type IV collagen domain derived from basement membrane

Vascular basement membrane is an important structural component of blood vessels. During angiogenesis this membrane undergoes many alterations and these changes are speculated to influence the formation of new capillaries. Type IV collagen is a major component of vascular basement membrane, and recently we identified a fragment of type IV collagen alpha2 chain with specific anti-angiogenic properties (Kamphaus, G. D., Colorado, P. C., Panka, D. J., Hopfer, H., Ramchandran, R., Torre, A., Maeshima, Y., Mier, J. W., Sukhatme, V. P., and Kalluri, R. (2000) J. Biol. Chem. 275, 1209-1215). In the present study we characterize two different antitumor activities associated with the noncollagenous 1 (NC1) domain of the alpha3 chain of type IV collagen. This domain was previously discovered to possess a C-terminal peptide sequence (amino acids 185-203) that inhibits melanoma cell proliferation (Han, J., Ohno, N., Pasco, S., Monboisse, J. C., Borel, J. P., and Kefalides, N. A. (1997) J. Biol. Chem. 272, 20395-20401). In the present study, we identify the anti-angiogenic capacity of this domain using several in vitro and in vivo assays. The alpha3(IV)NC1 inhibited in vivo neovascularization in matrigel plug assays and suppressed tumor growth of human renal cell carcinoma (786-O) and prostate carcinoma (PC-3) in mouse xenograft models associated with in vivo endothelial cell-specific apoptosis. The anti-angiogenic activity was localized to amino acids 54-132 using deletion mutagenesis. This anti-angiogenic region is separate from the 185-203 amino acid region responsible for the antitumor cell activity. Additionally, our experiments indicate that the antitumor cell activity is not realized until the peptide region is exposed by truncation of the alpha3(IV)NC1 domain, a requirement not essential for the anti-angiogenic activity of this domain. Collectively, these results effectively highlight the distinct and unique antitumor properties of the alpha3(IV)NC1 domain and the potential use of this molecule for inhibition of tumor growth.

Association of age and reproductive factors with benign breast tissue composition

Reproductive breast cancer risk factors are hypothesized to act by increasing exposure of the breast to endogenous estrogens, but few studies have quantitatively examined the association of these risk factors with breast tissue composition. This study is part of a case-control study of breast histological characteristics and breast cancer risk, nested within the Nurses' Health Study, a prospective study of 121,700 registered nurses. We studied 300 women who had not been diagnosed with breast cancer, but for whom we obtained slides from a prior benign breast biopsy. We used a computer-assisted image analysis technique to assess the proportion of epithelial and fibrous stromal tissue on benign breast biopsy slides, excluding obvious mass lesions. Mean epithelial proportion was 5.3% (0.1-23%), and mean stromal proportion was 58.7% (3-93%). Women with proliferative breast disease without atypia had higher epithelial and stromal proportions than women with nonproliferative breast disease (P < 0.001). Postmenopausal women had a lower epithelial proportion (P = 0.01), and increasing age at biopsy was associated with decreasing stromal proportion among postmenopausal parous women (P = 0.004). Among premenopausal women, increasing years since last birth was associated with lower epithelial proportion (P < 0.001). Other reproductive risk factors were not independently associated with epithelial or stromal proportion. Epithelial and stromal breast tissue were associated with different factors with the exception of proliferative breast disease, which was associated with an increase in both epithelial and stromal proportion. The quantitative measurement of epithelial and stromal proportion may be useful for measuring changes in breast composition.

Transforming growth factor beta1 is a target for the von Hippel-Lindau tumor suppressor and a critical growth factor for clear cell renal carcinoma

The von Hippel-Lindau (VHL) tumor suppressor gene is mutated in patients with VHL disease and in the majority of patients with sporadic clear cell renal carcinoma (RCC). Overexpression of transforming growth factor (TGF) beta1 has been observed in patients with several cancers, including RCCs, with serum and urine levels correlating inversely with prognosis. We have demonstrated that the VHL tumor suppressor gene product represses TGF-beta1 mRNA and protein levels (approximately 3-4-fold) in 786-O RCC cells by decreasing the TGF-beta1 mRNA half-life. Exogenously added TGF-beta1 did not suppress the growth of 786-O cells in vitro, nor did the addition of neutralizing antibody (Ab) against TGF-beta have any effect. Indeed, 786-O cells were found to express no TGF-beta type II receptor protein, thus allowing them to escape from the negative growth control of TGF-beta1. In contrast to the in vitro data, neutralizing Ab to TGF-beta inhibited tumorigenesis and, in some cases, regressed established 786-O tumors in athymic mice. Immunohistochemistry for von Willebrand's factor revealed a 3-4-fold lower tumor microvessel count in the mice treated with TGF-beta Ab compared to controls, suggesting that the Ab was inhibiting angiogenesis. Our findings indicate that TGF-beta1 is a novel target for the VHL tumor suppressor and that antagonizing its paracrine action may provide novel avenues for treatment of RCCs as well as other tumors that secrete TGF-beta1.

Adenoviral gene therapy leads to rapid induction of multiple chemokines and acute neutrophil-dependent hepatic injury in vivo

Replication-deficient adenoviruses are known to induce acute injury and inflammation of infected tissues, thus limiting their use for human gene therapy. However, molecular mechanisms triggering this response have not been fully defined. To characterize this response, chemokine expression was evaluated in DBA/2 mice following the intravenous administration of various adenoviral vectors. Administration of adCMVbeta gal, adCMV-GFP, or FG140 intravenously rapidly induced a consistent pattern of C-X-C and C-C chemokine expression in mouse liver in a dose-dependent fashion. One hour following infection with 10(10) PFU of adCMVbeta gal, hepatic levels of MIP-2 mRNA were increased >60-fold over baseline. MCP-1 and IP-10 mRNA levels were also increased immediately following infection with various adenoviral vectors, peaking at 6 hr with >25- and >100-fold expression, respectively. Early induction of RANTES and MIP-1beta mRNA by adenoviral vectors also occurred, but to a lesser degree. The induction of chemokines occurred independently of viral gene expression since psoralen-inactivated adenoviral particles produced an identical pattern of chemokine gene transcription within the first 16 hr of administration. The expression of chemokines correlated as expected with the influx of neutrophils and CD11b+ cells into the livers of infected animals. At high titers, all adenoviral vectors caused significant hepatic necrosis and apoptosis following systemic administration to DBA/2 mice. To investigate the role of neutrophils in this adenovirus-induced hepatic injury, animals were pretreated with neutralizing anti-MIP-2 antibodies or depleted of neutrophils. MIP-2 antagonism and neutrophil depletion both resulted in reduced serum ALT/AST levels and attenuation of the adenovirus-induced hepatic injury histologically, confirming that this early injury is largely due to chemokine production and neutrophil recruitment. Our findings further clarify the early immune response against replication-deficient adenoviral vectors and suggest a strategy to prevent adenovirus-mediated inflammation and tissue injury by interfering with chemokine or neutrophil function.

Endostatin: yeast production, mutants, and antitumor effect in renal cell carcinoma

Endostatin is a Mr 20,000 COOH-terminal fragment of collagen XVIII that inhibits the growth of several primary tumors. We report here the cloning and expression of mouse endostatin in both prokaryotic and eukaryotic expression systems. Soluble recombinant protein expressed in yeast (15-20 mg/L) inhibited the proliferation and migration of endothelial cells in response to stimulation by basic fibroblast growth factor. A rabbit polyclonal antibody was raised that showed positive immunoreactivity to the recombinant protein expressed from both systems. Importantly, the biological activity of the mouse recombinant protein could be neutralized by this antiserum in both endothelial proliferation and chorioallantoic membrane assays. Systemic administration of endostatin at 10 mg/kg suppressed the growth of renal cell cancer in a nude mouse model. The inhibition of tumor growth with soluble yeast-produced protein was comparable to that obtained with non-refolded precipitated protein expressed from bacteria. In addition, two closely related COOH-terminal deletion mutants of endostatin were also tested and showed strikingly differing activity. Collectively, these findings demonstrate the expression of a biologically active form of mouse endostatin in yeast, define a role for the molecule in inhibiting endothelial cell migration, extend its antitumor effects to renal cell carcinoma, and provide a formal proof (via the neutralizing antiserum experiments and the mutant data) that endostatin (and not a possible contaminant) acts as an antiangiogenic agent. Finally, the high level expression of mouse endostatin in yeast serves as an endotoxin free, soluble source of protein for fundamental studies on the mechanisms of tumor growth suppression by angiogenesis inhibitors.

Anti-glomerular basement membrane disease and dual positivity for antineutrophil cytoplasmic antibody in a patient with membranous nephropathy

We present the case of a 50-year-old man who underwent kidney biopsy for nephrotic syndrome. In addition to a membranous pattern, anti-glomerular basement membrane (anti-GBM) staining was noted before manifestations of anti-GBM disease. Hematuria and renal failure ensued 2 weeks later. In addition, he had simultaneous circulating levels of anti-GBM antibody and both perinuclear (P-) and cytoplasmic (C-) antineutrophil cytoplasmic antibody (ANCA).

Medullary injury in the ageing rat kidney: functional-morphometric correlations

Urinary concentrating ability decreases with age in both humans and animals. This phenomenon is not yet clearly explained or corroborated by morphological findings, often focused on glomerular changes. In rats aged 5-22 months, semi-quantitative and quantitative morphometric analysis was performed to score cortical and medullary changes. Morphological-data were related to renal functional parameters. Three stages of tubulo-interstitial injury were observed: minimal findings (stage I); mild fibrosis with atrophy and casts in medullary thick ascending limbs (stage II): extensive fibrosis and atrophy with large cast formation (stage III). Maximal urinary osmolality decreased in correlation with the stage of tubulointerstitial injury (r = -0.8, P < 0.001), from 3735 mosmol L-1 at stage I to 2807 at stage II and 1567 at stage III. A dissociation was observed in the rate of progression with age between tubulointerstitial injury and glomerular sclerosis. Whereas sclerosis was observed in only 2-3% of glomeruli at both stages I and II of tubulointerstitial injury, damage to thick ascending limbs significantly increased from 2% of tubules at stage 1 to 11% at stage II (P < 0.002). At stage III, both extensive glomerular sclerosis (53%) and tubular injury (32%) were present. Uninephrectomy accelerated both morphological injury and functional compromise. We conclude that, in the early stages of renal ageing, injury to medullary tubules may be more prevalent than injury to glomeruli and could be responsible for the reduction in concentrating ability.

Prednisone alters the histopathology of chronic cyclosporine nephropathy

The effects of prednisone (Pred) and azathioprine (Aza) on a rat model of chronic cyclosporine (CsA) nephropathy were studied. Twenty-four salt-depleted Sprague-Dawley rats were randomized to four groups: (1) control; (2) CsA 15 mg/kg; (3) CsA/Aza 5 mg/kg, and (4) CsA/Pred 1 mg/kg. After 4 weeks, functional measurements, including urinary N-acetyl-beta-D-glucosaminidase (NAG) levels, were determined. Semiquantitative grading of cortical and medullary damage was done. Cross-sectional areas of medullary thick ascending limbs (mTAL) and collecting ducts (CD) were determined. Tubulointerstitial injury was equivalent in all CsA groups, but tended to be lowest in the CsA/Pred group. Mean mTAL size in the CsA/Pred group was significantly greater than controls (p = 0.035). In contrast, mean CD size was not different among all groups. All CsA-treated animals had significantly larger hypertrophic mTAL than controls. The degree of hypertrophy was even greater in the CsA/Pred group (p = 0.006 vs. the other CsA-treated groups). Mean mTAL size was found to correlate with creatinine clearance, free water reabsorption, and urinary NAG. The percent of hypertrophic mTAL was found to correlate with creatinine clearance, free water reabsorption, and urinary NAG. This report shows that Pred alters the nephrotoxic effect of CsA, permitting a predominantly hypertrophic, rather than atrophic, medullary response. The extent of hypertrophy, in all CsA-treated groups, correlated with improved functional parameters, suggesting that at least in one phase of CsA nephropathy compensatory responses preserve renal function.

Loss of tumor marker-immunostaining intensity on stored paraffin slides of breast cancer

BACKGROUND

We previously observed decreased p53 immunostaining over time in paraffin-embedded sections of ductal carcinoma in situ of the breast of women; these sections had been stored on slides at room temperature. This observation suggests that slide storage adversely affects p53-immuno-staining intensity and could result in spurious negative staining for p53 in patient samples.

PURPOSE

The goals of this study were to determine the time course and factors influencing loss of p53 immunoreactivity and to investigate whether a similar loss of reactivity occurs with other antigens commonly used to study breast cancer.

METHODS

Serial sections cut from 12 formalin-fixed, paraffin-embedded, p53-positive invasive ductal carcinomas of the breast were stored on slides at room temperature or at 4 degrees C, with or without an additional paraffin coating, for 2, 4, 8, or 12 weeks. For each case, freshly cut slides from the same block (day 0) and stored slides were simultaneously stained for p53 by use of an automated immunostainer. Slides cut from formalin-fixed, paraffin-embedded breast carcinomas and stored for 12 weeks were also stained for factor VIII-related antigen (n = 12), estrogen receptor (ER) (n = 9), and Bcl-2 protein (n = 9). The staining intensity of all slides was assessed by visual microscopic examination and was also quantified by image analysis. Quantitative results were expressed as a percentage (mean +/- standard error) of the staining intensity on day 0. Data were analyzed by the Friedman Repeated Measures Analysis of Variance on Ranks, with statistical significance set at two-sided P < .05.

RESULTS

The intensity of p53 staining decreased over time in nine (75%) of the 12 cases studied. In three (or 25% of all cases studied) of the nine cases that showed decreased p53 staining, slides stored for 12 weeks were scored as p53 negative. Antigen loss on slides stored at 4 degrees C was significantly less than that on slides stored at room temperature at all time points (all P < .05). At 12 weeks, the average staining intensity of slides stored at 4 degrees C was 33.2% +/- 9% of that on day 0 compared with 8.4% +/- 3% of that on day 0 for slides stored at room temperature (P < .001). Paraffin coating of the sections did not significantly diminish antigen loss at either room temperature or 4 degrees C, except for slides stored at room temperature for 12 weeks. The intensity of factor VIII staining decreased in nine of 12 cases (average staining intensity, 37.3% +/- 6% of that on day 0 at 12 weeks; P = .0001). The intensity of ER and Bcl-2 staining decreased in all nine cases studied at 12 weeks (average staining intensity, 14.0% +/- 6% and 21.0% +/- 4% of that on day 0, respectively; P = .0001 for each).

CONCLUSIONS AND IMPLICATIONS

Slide storage, particularly at room temperature, results in substantial loss of p53 reactivity, with some p53-positive cases becoming p53 negative after 12 weeks of storage. Substantial loss of immunoreactivity for factor VIII, ER, and Bcl-2 occurs on slides stored at room temperature for 12 weeks. Storage of unstained slides for up to 12 weeks may lead to false-negative immunostaining for p53 and other antigens.

FK506 nephrotoxicity: morphologic and physiologic characterization of a rat model

BACKGROUND

FK506 is a useful agent in the prevention of allograft rejection but has recently been shown to be nephrotoxic.

EXPERIMENTAL DESIGN

Sprague-Dawley rats (n = 40) were divided into four groups: control (C); low-salt (LS); FK506, 3 mg/kg daily by gavage (FK); and FK506-low-salt (FK-LS). After 6 weeks, the animals underwent physiologic studies and were sacrificed with perfusion fixation of the kidneys. Semiquantitative analysis of morphologic injury was performed as well as grading of juxtaglomerular apparatus (JGA) granularity (1-micron plastic sections). Computer-assisted morphometry was used to measure medullary thick ascending limb (mTAL) size within the inner stripe.

RESULTS

Serum creatinine and plasma renin activity were significantly elevated only in the FK-LS group, but both FK groups had significantly increased fractional excretion of Mg. Tubular atrophy and fibrosis involving medullary rays and inner stripe (areas of low oxygen availability) was minimally present in FK, but prominent in FK-LS (P < 0.001). Injury correlated with decreased function (P < 0.001). Variance of mTAL size, an expression of co-existent tubular atrophy and hypertrophy was significantly greater in FK-LS and correlated with decreased renal function and urine osmolality (P < 0.001). JGA granularity was increased by FK506 (P < 0.006) with the highest values in FK-LS (P < 0.001), and strongly correlated with injury (P < 0.001). JGA granularity did not correlate with circulating renin activity levels, suggesting local activation of a renin-angiotensin system.

CONCLUSIONS

FK506 compromises renal parenchymal zones which are known to have limited oxygen availability (medullary ray and inner stripe), a pattern that has been observed with other nephrotoxins. The injury is potentiated by salt depletion and may be mediated by the renin-angiotensin system. Furthermore, these findings illustrate the close correlation between the medullary injury that was observed and the impaired function that was documented.

Effects of salt depletion on the kidney: changes in medullary oxygenation and thick ascending limb size

Previous studies have shown that salt depletion enhances the susceptibility of the kidney to nephrotoxins (amphotericin, cyclosporine, and contrast). To study the renal response to salt depletion, Sprague-Dawley rats were fed a sodium-deficient diet (N = 12) with pair-fed controls (N = 13) for 4 wk. In addition, rats from each group underwent 24-h water deprivation studies (N = 9; four salt deprived, five normal). Plastic 1-micron horizontal sections of mid-inner stripe were examined, and cross-sectional areas of the medullary thick ascending limb (mTAL) were analyzed. The mTAL of the salt-deprived rats were smaller (P = 0.04) and showed greater variance in size (P = 0.02) than control (618 +/- 106 versus 693 +/- 50 microns2). However, mean glomerular and collecting duct cross-sectional areas were unaffected by salt intake. Cross-sectional areas of long- and short-loop mTAL were significantly different, regardless of group (518 +/- 78 versus 732 +/- 92 microns2). Maximal urinary concentrating ability was found to correlate with mTAL cross-sectional area (r = 0.85; P = 0.004) and with long-loop mTAL size (r = 0.77; P = 0.016). However, it did not significantly correlate with short loop mTAL size (r = 0.53; P = 0.14).(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic amphotericin nephropathy: morphometric, electron microscopic, and functional studies

The two major hypotheses for the pathogenesis of amphotericin nephrotoxicity are direct interaction with epithelial cell membranes and vasoconstriction. Studies indicating the special vulnerability of the medullary ray and medulla to hypoxia led to a reexamination of amphotericin nephrotoxicity. Twenty-four rats were divided into four groups: amphotericin injection (5 mg/kg daily for 3 wk), amphotericin plus salt depletion, vehicle, and salt depletion and vehicle. The amphotericin group had polyuria (P < 0.01) but normal serum creatinine. In contrast, amphotericin plus salt depletion rats exhibited renal failure (creatinine of 1.49 +/- 0.05 versus amphotericin alone 0.98 +/- 0.01; P < 0.01). Semiquantitative histologic analysis of cortical and medullary injury correlated with functional impairment. Cortical changes in the amphotericin group were largely restricted to the medullary ray, where focal rupture and calcification of thick ascending limbs were noted. The S2/S3 tubules in the medullary rays showed focally diminished cell complexity with histiocytic/lymphocytic infiltration. However, calcification was also seen in the area of the macula densa. Morphometry revealed that the thick ascending limbs in the medulla were hypertrophied (1,420 +/- 63 versus 1,195 +/- 48 microns 2 for vehicle; P < 0.05). In contrast, in the amphotericin and salt depletion group, the changes in the medullary ray extended to the labyrinth and the thick ascending limbs in the inner stripe showed atrophic changes (772 +/- 23 microns 2; P < 0.01 versus vehicle). Thus, changes as a result of amphotericin toxicity take place both in areas known to be most vulnerable to hypoxia (medullary ray and medulla), and in areas rich in oxygen (adjacent to glomerulus). Salt depletion potentiates the cortical changes and converts medullary hypertrophy to atrophy. These findings support a dual pathogenesis for amphotericin nephropathy (direct toxicity and vasoconstriction).

Atherectomy of the subclavian artery for patients with symptomatic coronary-subclavian steal syndrome

OBJECTIVES

This study addresses the efficacy of directional atherectomy in the subclavian artery for the relief of angina in patients with the coronary-subclavian steal syndrome. In addition, we review the histologic findings from the atherectomy specimens.

BACKGROUND

The coronary-subclavian steal syndrome may occur after internal mammary-coronary artery bypass grafting. It is due to a stenosis in the subclavian artery proximal to the origin of the internal mammary artery and causes frank ischemia to the area supplied by the graft. Currently, surgery is the corrective procedure of choice.

METHODS

In three patients with severe subclavian artery stenoses and unstable angina, directional atherectomy was performed using a peripheral atherectomy catheter through a percutaneous femoral approach. The patients ranged from 43 to 71 years of age and had undergone internal mammary-coronary artery bypass grafting 3 to 10 years previously. Each patient had severe peripheral vascular and cerebrovascular disease.

RESULTS

All three patients had immediate symptomatic relief after the atherectomy, and postprocedure exercise testing demonstrated improved cardiac function. Two patients remain asymptomatic at 7 and 8 months, respectively; the third patient developed unstable angina 9 months later because of severe restenosis that was again successfully treated with atherectomy. Histologic examination of the specimens revealed atherosclerotic plaque, occasionally with adventitia. The specimen from the repeat atherectomy showed severe intimal hyperplasia.

CONCLUSIONS

Directional atherectomy appears to be a safe and effective treatment for coronary-subclavian steal syndrome. This procedure may be the treatment of choice for patients in whom a vascular bypass operation is not feasible.

Myocardial fibrin deposition in experimental viral myocarditis that progresses to dilated cardiomyopathy

Myocardial fibrosis is a characteristic late feature in cases of viral myocarditis that progress to dilated cardiomyopathy. However, the pathogenesis of the myocardial fibrosis in such cases is unknown. Prior studies have shown that in healing wounds and tumor stroma generation, interstitial fibrin deposition precedes the development of fibrosis. Therefore, interstitial fibrin deposition in the myocardium was investigated in a murine model of myocarditis in which dilated cardiomyopathy develops. Inbred male C3H/He mice inoculated with coxsackievirus B3 were killed 0, 3, 7, 14, 21, 30, and 60 days after infection. Paraffin sections of hearts were stained with hematoxylin-eosin, Masson's trichrome stain, and antibodies to fibrinogen/fibrin by use of an immunoperoxidase technique. Pretreatment of all mice with anticoagulants and antifibrinolytics 5 minutes before death was used to prevent artifactual fibrin deposition and fibrinolysis during tissue manipulation. Tissue fixation in formalin supplemented with acetic acid served to extract non-cross-linked fibrin, fibrinogen, and fibrinogen and fibrin degradation products, thus ensuring that clotted and cross-linked fibrin was the major immunoreactant. Myocardial fibrin deposition and fibrosis were each quantitated by computer-assisted image analysis. Myocardial fibrin deposition first appeared on day 3, was maximal on day 14, and disappeared by day 30. Conversely, myocardial fibrosis was not detectable until day 14 and was maximal at day 60. Thus, as in healing wounds and developing tumor stroma, fibrin deposition preceded fibrosis in this murine model of myocarditis that progresses to dilated cardiomyopathy.

Cyclosporine nephropathy: morphometric analysis of the medullary thick ascending limb

The effects of cyclosporine A (CsA) (12.5 mg/kg/d) on the medullary thick ascending limb (mTAL) were studied in five experimental groups: vehicle-treated control (C), salt depletion (SD), cyclosporine (CsA), and the combination of both salt depletion and cyclosporine for 3 (CsA-SD:S) and 8 (CsA-SD:L) weeks. Evaluation was performed on 1-micron plastic horizontal sections. mTALs were classified as either atrophic or nonatrophic by assessing mitochondrial density. The mean cross-sectional area of atrophic mTALs was found to be significantly smaller than the mean of nonatrophic mTALs in all treatment groups. The percentage of atrophic tubules was found to be significantly increased in both CsA-SD groups as compared with the other three treatment groups (P less than 0.01). Regression analysis indicated a rectangular hyperbolic relationship between the percentage of atrophic tubules and mean nonatrophic tubule cross-sectional area (P less than 0.0001). Thus, low levels of injury are associated with a rapid increase in cross-sectional tubular area (hypertrophy), and this response plateaued with increasing degrees of injury. Terminal plasma creatinine correlated with nonatrophic tubular cross-section area (r = 0.52, P less than 0.003). These studies indicate that CsA induces mTAL atrophy, which is more extensive with salt depletion. With limited injury, hypertrophy develops. However, the hypertrophic response cannot be sustained with increasing degrees of injury. The phenomenon of mTAL atrophy and hypertrophy is particularly important, since hypertrophy itself is a known risk factor for mTAL injury.