Differential expression of WISP-1 and WISP-2 genes in normal and transformed human breast cell lines

The transcriptional alterations of specific gene(s) are actively associated with the development of different cancers including breast. The preceding studies of different laboratories documented at least 40 genes that may contribute directly to the genesis of cancer. Using differential display, RT-PCR and DNA sequencing analyses in normal human mammary epithelial cells (HMEC) and various breast tumor cell lines including MCF-7, ZR-75, T-47D and SKBR2, we demonstrated that WISP-1 and WISP-2 genes are differentially transcribed in these cells. WISP-2 mRNA transcription was identified in all 4 tumor derived cell lines, but the mRNA expression was undetected or minimally detected in normal breast epithelial cells. WISP-1 mRNA expression was identified in normal and transformed cell lines. However, the level of expression was higher in different breast tumor cell lines as compared to HMEC. The mRNA expression profiles of WISP genes in normal breast epithelial cells and breast tumor derived cell lines indicated a strong possibility of the involvement of WISP-signaling in the development of human breast tumors, and can be utilized as genetic markers of this disease.

WISP-2: a serum-inducible gene differentially expressed in human normal breast epithelial cells and in MCF-7 breast tumor cells

WISP-2 is a Wnt-1-induced signaling protein identified as a member of CCN growth factor family. A role for this molecule during tumorigenesis is suspected but remains unproven. Here we show that WISP-2 expression was undetectable, or minimally detectable, in nontransformed human mammary epithelial cells, but was overexpressed in MCF-7 cells. Expression of WISP-2 in MCF-7 cells was modulated by serum and correlated with the serum-induced MCF-7 tumor cell proliferation, suggesting that WISP-2 is serum responsive and may be a positive regulator of tumor cell proliferation.

Identification of genomic imbalances in gastric MALT lymphoma using arbitrarily primed PCR DNA fingerprinting

Arbitrarily primed PCR (AP-PCR) is a unique method to identify the cancer cell specific losses and gains of chromosomal regions by targeting specific genes or chromosomal segments. In the present study, introducing the AP-PCR technique with a single primer, we have ascertained the gains and losses of DNA fingerprints in 15 MALT lymphoma samples. Out of 15 prominent DNA fingerprints, the signal intensity of two fingerprints, labeled bands G and I, were significantly lower in 40 and 50% of tumors as compared to adjacent normal DNA fingerprints, respectively. Similarly, gains of signal intensity of DNA fingerprints (bands A and C) were detected in 13% of tumor samples studied. Variations in signal intensities were also found in other bands within a few samples. Although, the functional importance of these bands is unknown, this study indicates that the AP-PCR generated under or over amplified DNA fingerprints may participate during the progression of MALT lymphoma in human stomach. Moreover, these studies also suggest that the AP-PCR technique, with different primers, can be utilized for the determination of new chromosomal segments in MALT lymphoma samples that can be used for the identification of these diseases.

Selective developmental regulation of gene expression for insulin-like growth factor-binding proteins in mouse spinal cord

STUDY DESIGN

Prospective, randomized experimental study in mice.

STUDY OBJECTIVE

To determine whether insulin-like growth factor binding proteins (IGFBPs) are present in mouse spinal cord and, if so, what role they play in its development.

SUMMARY OF BACKGROUND DATA

Insulin-like growth factors are well recognized hormonal effectors of growth hormone and are expressed in the mammalian spinal cord. The IGFBPs are a group of six genetically distinct proteins that bind IGFs and modulate their bioactivity. They appear in the brain during development, localize to the neuromuscular junction, and promote motor neuron survival. The benefit of IGF-I in amyotrophic lateral sclerosis ALS and its potential use in preventing motor neuron apoptosis in spinal cord injury dictates that studies of the presence and response of IGFBPs in that tissue be performed.

METHODS

The IGFBPs in mouse spinal cord were analyzed by Western ligand blot, Western immunoblot, and reverse transcription-polymerase chain reaction at various time points from embryonic day 14 to postnatal day 30.

RESULTS

Three IGFBPs with molecular masses of 24, 28, and 32 kDa were found, the latter two being the most prominent. The data indicate that these are IGFBP-4, -5, and -2.

CONCLUSION

Both IGFBP-2 and BP-5 are developmentally regulated in mouse spinal cord, with higher levels of those at early embryonic stages indicating their potential role in development of the mouse spinal cord.

2-Methoxyestradiol blocks estrogen-induced rat pituitary tumor growth and tumor angiogenesis: possible role of vascular endothelial growth factor

Natural and synthetic estrogens have been associated with several types of human and animal cancers including prolactin-secreting pituitary tumors in Fischer 344 rats. These prolactin-secreting tumors are highly angiogenic and their growth is angiogenic dependent. In the present study we have utilized this model to evaluate the effect of 2-methoxyestradiol (2-ME), an endogenous estrogen metabolite that is a potent inhibitor of endothelial cell proliferation in vitro, on estrogen-induced pituitary tumor growth and angiogenesis. Adult female rats were implanted (subcutaneously) with a silastic capsule containing estradiol-17beta (E2). After seven days of constant E2 exposure animals were injected (sc) daily with 25 mg/kg of 2-ME and killed either three or 8 days later. Changes in pituitary weight and proliferating cell nuclear antigen (PCNA) labeling index indicated growth while degree of angiogenesis was determined immunohistochemically using factor VIII related antigen. The results indicate that 2-ME inhibited estrogen-induced lactotroph growth by 32% and tumor angiogenesis by 89%. Furthermore, vascular endothelial growth factor (VEGF) expression, evaluated by immunohistochemical analysis, was down-regulated concomitant with tumor angiogenic suppression. These studies suggest that 2-ME may have therapeutic potential for hormone-induced cancer and that its angiostatic activity may be modulated through down-regulation of VEGF expression.

Tumor angiogenesis in chronic pancreatitis and pancreatic adenocarcinoma: impact of K-ras mutations

Chronic pancreatitis (CP) is one condition in which epidemiologic studies have demonstrated a definite association with pancreatic adenocarcinoma (PAC). The pathophysiologic and molecular events that either predispose to the development of, or potentiate the growth of, PAC are unknown. Mutation of the codon 12 K-ras gene is one genetic aberration commonly associated with development of PAC. Tumor angiogenesis, or microvascular proliferation of new capillaries, is another pathophysiologic alteration associated with PAC. Although activated ras oncogenes modulate tumor angiogenesis/neovascularization in some tumors, the importance of tumor angiogenesis and the role of K-ras mutation in regulating angiogenesis in CP and PAC are unknown. The aim of this study was to elucidate the relationship between angiogenesis and K-ras mutations in CP and PAC. Tumor angiogenesis and K-ras mutations were evaluated in resected specimens from 25 CP (23 CP plus two CP with PAC) and 16 PAC patients. Tumor angiogenesis was determined using immunohistochemistry of factor VIII-related antigen (FVIIIRAg) and ras mutations were identified by enriched-nested polymerase chain reaction. The mean number of FVIIIRAg-positive blood vessels was significantly (p < 0.005) higher in PAC (23.0 +/- 7.5), CP with a mutant K-ras genome (17.7 +/- 2.8) and CP with a normal K-ras genome (6.5 +/- 3.8), compared to unaffected areas. Codon 12 K-ras mutations were detected in three of 25 CP specimens (12%) and in 15 of 16 PAC specimens (94%). In CP patients with mutant K-ras in their genome, microvessel density was significantly (p < 0.01) elevated, compared to patients with a normal K-ras genome. Statistical analyses (Spearman rank-difference correlation coefficient, Student t test, and chi2 analysis) indicated a significant association between codon 12 K-ras mutations and tumor angiogenesis in both CP and PAC. This study demonstrates a significant association between angiogenesis and K-ras mutation in both PAC and CP. At a minimum, K-ras mutation is associated with the events that increase angiogenesis and it may potentiate or promote tumor angiogenesis.

Overexpression of vascular endothelial growth factor164 and its co-receptor neuropilin-1 in estrogen-induced rat pituitary tumors and GH3 rat pituitary tumor cells

We have shown previously that the VEGF system plays a crucial role in regulation of tumor angiogenesis during the development of estrogen-induced prolactin-secreting pituitary tumors in Fisher 344 rats. Studies also suggested that both endothelial and non-endothelial cells expressed VEGF. However, several questions concerning the VEGF signals in regulation of estrogen-induced angiogenesis in rat pituitary remained unanswered. VEGF exists in a number of isoforms in human and rodent tissue (i.e., VEGF206h/205r, VEGF189h/188r, VEGF165h/164r, VEGF145h/144r and VEGF121) that differ in their molecular masses and biological activities. The VEGF isoforms bind with two tyrosine-kinase receptors, KDR/flk-1 and flt-1. In addition, VEGF165 binds with a newly identified co-receptor, neuropilin-1, which is expressed in human endothelial cells and several types of non-endothelial cells including tumor cells. The present study was undertaken to elucidate which isoforms of VEGF are predominantly expressed in normal Fisher 344 rat pituitaries, estrogen-induced prolactin secreting rat pituitary tumors and in prolactin secreting rat pituitary tumor cell line (GH3 cell line). To identify the isoform, RT-PCR with primer pairs derived from exon 1 and exon 8 of the VEGF gene, cloning, sequencing and Western blot analysis were performed. The status of neuropilin-1 in the rat pituitaries (normal and transformed) and GH3 pituitary tumor cell line has also been investigated using RT-PCR and Western blot analysis. These studies demonstrate that normal rat pituitaries, estrogen-induced rat pituitary tumors and GH3 pituitary tumor cells expressed VEGF164 and co-receptor, neuropilin-1. The VEGF164 was the predominant form in all of these cells. The VEGF164 and neuropilin-1 mRNA and protein levels were significantly higher in the estrogen-induced pituitary tumors and GH3 tumor cell line, as compared to normal pituitary. The data suggest that both VEGF164 and neuropilin-1 may actively participate in modulation of tumor angiogenesis and the development of pituitary tumors in Fisher 344 rats.

Prospective long-term endoscopic and histologic follow-up of gastric lymphoproliferative disease of early stage IE low-grade B-cell mucosa-associated lymphoid tissue type following Helicobacter pylori eradication treatment

Long-term endoscopic and histologic follow-up of Stage IE gastric lymphoproliferative disease of the low-grade B-cell mucosa-associated lymphoid tissue (MALT) type following cure of H. pylori was undertaken. Clinical and endoscopic features (age, race, endoscopic appearance, cure of H. pylori and duration of follow-up) were also evaluated as potential prognostic indicators for complete or near-complete regression of low-grade MALT lymphoma. Sixty-eight MALT lymphoma patients prospectively underwent H. pylori eradication. follow-up at periodic intervals with endoscopy and extensive mucosal biopsy protocol on 65 patients ranging from 12 weeks up to 73 months (mean +/- SD of 22.5+/-15.8 months) has been completed. H. pylori was eradicated in 89.2% of MALT lymphoma patients with complete histologic regression noted in 58.5%, near-complete regression in 18.5%, partial in 4.6%, and no change in 18.5%. Univariate analysis revealed two factors predictive of complete and/or near complete MALT lymphoma regression, H. pylori cure (p=0. 001) and duration of follow-up (p=0.001). Stepwise logistic regression also demonstrated that both H. pylori cure (p<0.0001) and duration of follow-up (p<0.02) were independently associated with complete and near complete MALT lymphoma regression. Age, race, and endoscopic appearance were not predictive of regression. We conclude that this lymphoproliferative disease predictably undergoes complete to near-complete histologic regression at variable rates following cure of H. pylori in a majority of patients.

2-methoxyestradiol-induced growth suppression and lethality in estrogen-responsive MCF-7 cells may be mediated by down regulation of p34cdc2 and cyclin B1 expression

MCF-7 breast cancer cells increase their rate of proliferation, as indicated by incorporation of tritiated thymidine into DNA, when exposed to estrogen. In confirmation of other studies, 10 nM 17beta-estradiol (E2) increased proliferation by 2.8-fold after 6 days of exposure. As indicated by trypan blue exclusion and TUNEL assays, cell survival was increased and apoptosis decreased by the presence of E2. The estradiol metabolite 2-methoxyestradiol (2-ME) when present in the culture medium in concentrations greater than 1 microM for three days, dose-dependently reduced the effectiveness of E2 on cell proliferation by increasing the rate of apoptosis. To examine a mechanism for the increase in apoptosis, expression of p34cdc2 and cyclin B1 protein levels were monitored by examination of immunoblots of their proteins. E2 increased p34cdc2 and cyclin B1 protein levels significantly after 6 days of exposure. This effect was inhibited significantly by the presence of 2-ME. The results indicate that up-regulation of p34cdc2 and cyclin B1 is closely associated with increased survivability and lack of apoptosis in estrogen-induced proliferation of MCF-7 cells. Further, anti-estrogenic effects of 2-ME in these cells can be accounted for by its activation of apoptotic functions, which are correlated with reductions in expression of p34cdc2 and cyclin B1 genes.

Apoptosis in cellular compartments of rat spinal cord after severe contusion injury

Following a controlled, severe contusion lesion to the lower thoracic spinal cord in adult rats, we found that apoptosis occurred in cells located in both gray and white matter. This suggested that both nonneuronal cells, including astrocytes, oligodendroglia and microglia, as well as neurons, might participate in programmed cell death (PCD) following spinal cord injury (SCI). Determination of which cell populations participate, and the kinetics and extent of their involvement might reveal new paradigms for approaches to therapy. Consequently, we assessed the functional deficit, comparing a comprehensive locomotor rating scale (LRS) with the inclined plane test at various times after injury. Using standard histology, along with cell-specific markers, we assessed PCD in different spinal cord segments using several parameters of apoptosis. Our results indicate that hind limb motor function was lost at day 1, and then only gradually and ineffectively (about 10-15%) recovered over the next month. Evidence for increased cell number was present for astrocytes and microglia beginning at day 1 after injury. Over the postinjury time period, apoptotic cells appeared (from day 1 to 14), and peaked (in terms of apoptotic index) on day 3. About one-third were microglia, whereas neurons, both large and small, also underwent apoptosis, again peaking at day 3. However, neurons continued to die and were not replaced by proliferation, so that at day 7, three times as many neurons (as a percentage) underwent PCD compared with the glial compartment. Oligodendrocytes also underwent apoptosis, with a biphasic curve, both at days 3 and 14 following injury. Thus, in addition to immediate, passive necrosis, delayed and apoptotic PCD also occurred in all cell populations in severely injured spinal cord.

Specificity of polymerase chain reaction monoclonality for diagnosis of gastric mucosa-associated lymphoid tissue (MALT) lymphoma: direct comparison to Southern blot gene rearrangement

The specificity of polymerase chain reaction monoclonality in the diagnosis of gastric lymphoma was prospectively evaluated. Gastric mucosal tissue from normal gastric mucosa (N = 13), benign gastric ulcers (N = 3), chronic Helicobacter pylori gastritis (N = 3), gastric mucosa-associated lymphoid tissue (N = 16), and gastric lymphoma (N = 15) was obtained. Polymerase chain reaction amplification of the heavy-chain framework 2A gene was performed. The sensitivity and specificity of heavy-chain clonality, in the detection of gastric lymphoma, were 73.3% and 45.7%, respectively. Determination of monoclonality by polymerase chain reaction methodology is not an acceptable technique for confirming the diagnosis of gastric lymphoma as it is too sensitive, detecting minute populations of clonal lymphocytes that occur in benign diseases as well as larger populations of clonal lymphocytes associated with malignant gastric lymphoproliferative diseases. Southern blot gene rearrangement testing should be utilized to determine clonality in the evaluation of gastric lymphocytic infiltrates.

Quantitative PCR analysis reveals novel expression of prothrombin mRNA and regulation of its levels in developing mouse muscle

Precise determination of mRNA levels is an essential element in any investigation of complex regulatory systems. Classical methodologies such as Northern hybridization suffer from requirements for significant samples of material and also a degree of nonspecificity. Recently, quantitative techniques involving PCR amplification have been devised. We have developed and applied such procedures to the determination of prothrombin messages in skeletal muscle cells during development. In addition to its role in the blood coagulation cascade, the serine protease thrombin has been shown to participate in several signaling events in the neuromuscular system. The inactive precursor, prothrombin, primarily produced in the liver, has also been shown to be synthesized and developmentally-regulated in the brain. In skeletal muscle, thrombin is a mediator of activity-dependent polyneuronal synapse elimination (ADPSE) which occurs in early postnatal development. Recent experiments showing that thrombin is released from myotubes in culture under the influence of acetylcholine suggest that locally-synthesized prothrombin may be the source of this Hebbian synaptic interaction. We have determined that prothrombin is expressed in skeletal muscle, as the likely source of thrombin involved in ADPSE, and the current results show the quantitative expression of muscle prothrombin during this time of intense synapse remodeling.

A molecular mechanism for synapse elimination: novel inhibition of locally generated thrombin delays synapse loss in neonatal mouse muscle

Activity-dependent, polyneuronal synapse elimination (ADPSE) is a programmed, regressive event in the development of the nervous system and readily studied at the neuromuscular junction, where it is complete 15-20 days after birth. Local excess, or imbalanced, protease activity is one of several possible underlying mechanisms. In this regard, thrombin mediates activity-dependent synapse loss in an in vitro model of ADPSE. To test the involvement of thrombin in vivo, we locally applied the leech thrombin-specific inhibitor, hirudin. We monitored neuromuscular behavior, correlated with acetylcholinesterase and silver nitrate histochemistry at endplates, for changes in the timecourse of in vivo synapse elimination and assayed both thrombin activity and prothrombin expression in developing muscle. Hirudin retarded elimination, without altering motor performance, uniquely at Postnatal Day 5 (P5) and maximally at P9. Reverse transcription-polymerase chain reaction (PCR) showed that neonatal muscle was a source of local prothrombin, with peak expression during the first week after birth. A specific chromogenic assay revealed that local thrombin, activated from muscle-derived prothrombin, peaked during maximal synapse remodeling.

Cross-linking of beta-amyloid protein precursor catalyzed by tissue transglutaminase

Alzheimer's disease is characterized by progressive dementia, cortical atrophy with synaptic loss, and the accumulation of neurofibrillary tangles and senile plaques containing beta-amyloid. The beta-amyloid protein precursor (beta-APP), may normally be involved in cell adhesion related to synaptic maintenance. Loss of synapses correlates with dementia, suggesting that synaptic deficits may underlie the disease. Synapse stability may depend on the action of tissue transglutaminase (tTG), an enzyme capable of crosslinking large, multi-domain extracellular glycoproteins, that is active and present at synapses. We now show that beta-APP is a substrate for tTG in vitro that results in dimers and multimers by silver staining and immunoblotting. This novel post-translational modification suggests further roles for beta-APP in synaptic function as well as in Alzheimer's disease.