Reversal of GSTP1 CpG island hypermethylation and reactivation of pi-class glutathione S-transferase (GSTP1) expression in human prostate cancer cells by treatment with procainamide.

Among the many somatic genome alterations present in cancer cells, changes in DNA methylation may represent reversible "epigenetic" lesions, rather than irreversible "genetic" alterations. Cancer cell DNA is typically characterized by increases in the methylation of CpG dinucleotides clustered into CpG islands, near the transcriptional regulatory regions of critical genes, and by an overall reduction in CpG dinucleotide methylation. The transcriptional "silencing" of gene expression associated with such CpG island DNA hypermethylation presents an attractive therapeutic target: restoration of "silenced" gene expression may be possible via therapeutic reversal of CpG island hypermethylation. 5-Aza-cytidine (5-aza-C) and 5-aza-deoxycytidine (5-aza-dC), nucleoside analogue inhibitors of DNA methyltransferases, have been widely used in attempts to reverse abnormal DNA hypermethylation in cancer cells and restore "silenced" gene expression. However, clinical utility of the nucleoside analogue DNA methyltransferase inhibitors has been limited somewhat by myelosuppression and other side effects. Many of these side effects are characteristic of nucleoside analogues that are not DNA methyltransferase inhibitors, offering the possibility that nonnucleoside analogue DNA methyltransferase inhibitors might not possess such side effects. Human prostate cancer (PCA) cells characteristically contain hypermethylated CpG island sequences encompassing the transcriptional regulatory region of GSTP1, the gene encoding the pi-class glutathione S-transferase (GSTP1), and fail to express GSTP1 as a consequence of transcriptional "silencing." Inactivation of GSTP1 by CpG island hypermethylation, the most common somatic genome alteration yet reported for human PCAs, occurs early during human prostatic carcinogenesis and results in a loss of GSTP1 "caretaker" function, leaving prostate cells with inadequate defenses against oxidant and electrophile carcinogens. We report here that the drug procainamide, a nonnucleoside inhibitor of DNA methyltransferases, reversed GSTP1 CpG island hypermethylation and restored GSTP1 expression in LNCaP human PCA cells propagated in vitro or in vivo as xenograft tumors in athymic nude mice.

Cyclooxygenase-2 is up-regulated in proliferative inflammatory atrophy of the prostate, but not in prostate carcinoma.

Cyclooxygenase-2 (COX-2) is the inducible isoform of the rate-limiting enzymes that convert arachidonic acid to proinflammatory prostaglandins as well as a primary target for nonsteroidal anti-inflammatory drugs. Accumulating evidence suggests that up-regulation of COX-2 is associated with carcinogenesis in multiple organ systems including the large bowel, lung, breast, and prostate. In this report, we examine the expression of COX-2 protein and mRNA in prostate tissue containing various lesions and in prostate cancer cell lines. In the cell lines, LNCaP, DU145, PC-3, and TSU, COX-2 protein expression was undetectable under basal conditions but could be induced transiently by phorbol ester treatment in PC-3 and TSU cells, but not in DU145 and LNCaP cells. Immunohistochemical analysis of 144 human prostate cancer cases suggested that, in contrast to several previous reports, there was no consistent overexpression of COX-2 in established prostate cancer or high-grade prostatic intraepithelial neoplasia, as compared with adjacent normal prostate tissue. Positive staining was seen only in scattered cells (<1%) in both tumor and normal tissue regions but was much more consistently observed in areas of proliferative inflammatory atrophy, lesions that have been implicated in prostatic carcinogenesis. Staining was also seen at times in macrophages. Western blotting and quantitative RT-PCR analyses confirmed these patterns of expression. These results suggest that if nonsteroidal anti-inflammatory drugs are indeed chemopreventive and/or chemotherapeutic for prostate cancer, their effects are likely to be mediated by modulating COX-2 activity in non-PCa cells (either inflammatory cells or atrophic epithelial cells) or by affecting a COX-2-independent pathway.

Canine model of infertility after spinal cord injury: time course of acute changes in semen quality and spermatogenesis.

PURPOSE: We established a canine model of subfertility after spinal cord injury and examined the time course of acute changes in semen quality and spermatogenesis after spinal cord injury. MATERIALS AND METHODS: Seven dogs underwent surgical T7 spinal cord injury. Six dogs were used as controls. Electroejaculation and testicular fine needle aspiration were performed at baseline and twice weekly for 3 weeks after spinal cord injury. Semen quality change was examined by standard semen analysis. Spermatogenesis was assessed by flow cytometry of testicular fine needle aspiration in all dogs as well as by testicular histology at study conclusion in 4 controls and 4 spinal cord injured dogs. RESULTS: No significant changes in spinal cord injured dogs were noted before 3 weeks after injury. From baseline to 3 weeks after injury certain changes were evident in spinal cord injured dogs. Mean antegrade sperm motility decreased from 62.9% to 20.1% (p = 0.008), mean total sperm (antegrade plus retrograde total sperm) decreased from 423 to 294 x 106 which was not statistically significant, and the incidence of testicular haploid cells decreased from 75.6% to 48.3% (p = 0.028). No significant change in any parameter was present in control dogs. The mean number of mature spermatids per cross-sectional tubule on final testicular histology was significantly decreased in spinal cord injured dogs compared with controls (13.6 versus 43.9, p = 0.02). CONCLUSIONS: In the canine model tested the dogs readily survived spinal cord injury, electroejaculation was effective for obtaining ejaculate and fine needle aspiration allowed serial examination of spermatogenesis. Three weeks after spinal cord injury but not before 3 weeks sperm motility and spermatogenesis were significantly decreased. However, at the same point this decrease in spermatogenesis was not yet reflected in the total ejaculated sperm count.

Prostate pathology: histologic and molecular perspectives.

The field of prostate cancer research is poised for dramatic improvements in our ability to better diagnose men at risk of prostate cancer and to better predict prognosis and response to treatment. Histopathologic and molecular analyses lie at the heart of these issues. Improvements in our understanding of the mechanisms of prostate carcinogenesis and in determining why the prostate seems to be so highly targeted for cancer development will lead to rational strategies of disease prevention.

New concepts in the pathology of prostatic epithelial carcinogenesis.

The development of drugs to prevent prostate cancer is underway, yet monitoring the potential efficacy of these agents during clinical trials relies on measuring intermediate endpoints. In this review, various candidate markers are presented that are under different stages of evaluation as intermediate endpoint biomarkers. In addition, the near future will bring an unprecedented wave of new potential biomarkers. For instance, through genomics-based methods many new genes are being discovered whose altered expression may be involved in different phases of prostate cancer development and progression. In the development of rational approaches for selecting which of these untested biomarkers may be useful to measure systematically, there must be an improved understanding of the mechanisms of prostatic carcinogenesis. We submit that this improved understanding will come through new knowledge of the biology of normal prostate epithelial cells, the determination of the precise target cells of transformation, and how their growth regulation is genetically and epigenetically perturbed during the phases of initiation and progression. In this review, therefore, we also present our recent immune-mediated oxidant injury and regeneration hypothesis of why and how the prostate is targeted for carcinogenesis.

Preneoplastic prostate lesions: an opportunity for prostate cancer prevention.

Environmental factors, especially the diet, play a prominent role in the epidemic of prostate cancer (PCA), in the United States. Many candidate dietary components have been proposed to influence human prostatic carcinogenesis, including fat, calories, fruits and vegetables, anti-oxidants, and various micronutrients, but the specific roles dietary agents play in promoting or preventing PCA remain controversial. We have collected evidence to suggest that GSTP1, the gene encoding the pi-class glutathione S-transferase (GST), may serve a "caretaker" function for prostatic cells. Although GSTP1 can be detected in normal prostatic epithelium, in almost all PCA cases, PCA cells fail to express GSTP1 polypeptides, and lack of GSTP1 expression most often appears to be the result of somatic "CpG island" DNA methylation changes. Loss of GSTP1 function also appears to be characteristic of prostatic epithelial neoplasia (PIN) lesions, thought to represent PCA precursors. We have recently learned that a new candidate early PCA precursor lesion, proliferative inflammatory atrophy (PIA), characterized by proliferating prostatic cells juxtaposed to inflammatory cells, contains epithelial cells that express high levels of GSTP1. These findings have formed the basis for a new model of prostatic carcinogenesis, in which prostatic cells in PIA lesions, subjected to a barrage of inflammatory oxidants, induce GSTP1 expression as a defense against oxidative genome damage. When cells with defective GSTP1 genes appear amongst the PIA cells, such cells become vulnerable to oxidants and electrophiles that inflict genome damage that tends to promote neoplastic transformation to PIN and PCA cells. Subsequently, PIN and PCA cells with defective GSTPI genes remain vulnerable to similar stresses tending to promote malignant progression. This new model for prostatic carcinogenesis has implications for the design of new prostate cancer prevention strategies. Rational prevention approaches might include: (i) restoration of GSTPI expression via treatment with inhibitors of CpG methylation, (ii) compensation for inadequate GSTPI activity via treatment with inducers of general GST activity, and (iii) abrogation of genome-damaging stresses via avoidance of exogenous carcinogens and/or reduction of endogenous carcinogenic (particularly oxidant) stresses.

Morphologic transitions between proliferative inflammatory atrophy and high-grade prostatic intraepithelial neoplasia.

OBJECTIVES: To validate with an independent study that simple atrophy/postatrophic hyperplastic lesions (proliferative inflammatory atrophy [PIA]) often merge directly with high-grade prostatic intraepithelial neoplasia (PIN). METHODS: Using radical prostatectomies (n =14), all high-grade PIN and adenocarcinoma lesions were identified. We examined the two-dimensional topographic relationship between individual high-grade PIN lesions and PIA, between carcinoma lesions and PIA, and between carcinoma lesions and high-grade PIN. To reduce the possibility that high-grade PIN lesions represented intraprostatic dissemination of carcinoma, all specimens contained total carcinoma volumes of less than 0.5 cc. RESULTS: High-grade PIN merged with PIA in 267 (42.5% of high-grade PIN lesions) of 629 lesions, was adjacent in 57 lesions (9%), was near in 233 lesions (37%), and was distant from PIA in 72 lesions (11.5%). Carcinoma did not merge with PIA; it was adjacent in 24 (30. 4%) of 79 lesions, was near in 46 lesions (58.2%), and was distant from PIA in 9 lesions (11.4%). Of 79 carcinoma lesions, 18 (23%) merged with high-grade PIN, 11 (14%) were adjacent, 26 (33%) were near, and 24 (30%) were distant from high-grade PIN. Areas of presumed low-grade PIN were often found in association with high-grade PIN and PIA. CONCLUSIONS: Morphologic transitions between high-grade PIN and PIA occur frequently. Although the mere topographic relation of the lesions is not definitive proof of a continuum, these results are consistent with a model in which the proliferative epithelium in PIA may progress to PIN and/or adenocarcinoma.

Renal malacoplakia.

We present a well-documented case of biopsy-proven renal malacoplakia with an excellent response to oral fluoroquinolone therapy.

Papillary squamous cell carcinoma versus verrucous squamous cell carcinoma of the head and neck.

Papillary squamous cell carcinoma and verrucous squamous cell carcinoma of the head and neck may be confused. The clinicopathological profile of the two neoplasms is presented and the differential diagnosis is discussed. A correct diagnosis is imperative in order to institute the most appropriate treatment.

Head and neck Langerhans cell histiocytosis.

Among the potential sites of involvement by Langerhans cell histiocytosis (LCH), the head and neck region is the most commonly cited. Though principally a pediatric disease, LCH can affect any age group. It can be unifocal (skeletal) or multifocal (skeletal and/or visceral); it appears as though the presence of visceral lesions is more common in the youngest patients, and may be associated in some with a rapidly progressive course resulting in death. Head and neck manifestations may mimic such varied entities as eczema, otitis media, osteomyelitis, and cholesteatoma. Current approaches to therapy are less aggressive than they were in the past, and are particularly intended to monitor for and treat any complicating secondary infections (which may develop in the youngest patients with multifocal disease including visceral involvement). The prognosis is very good for unifocal skeletal system disease, and poor for multifocal disease with involvement of tissues other than bone.

XY sex reversal and gonadal dysgenesis due to 9p24 monosomy.

We describe a case of XY sex reversal, gonadal dysgenesis, and gonadoblastoma in a patient with a deletion of 9p24 due to a familial translocation. The rearranged chromosome 9 was inherited from the father; the patient's karyotype was 46,XY,der(9)t(8;9) (p21;p24)pat. A review shows that 6 additional patients with 46,XY sex reversal associated with monosomy of the distal short arm of chromosome 9 have been observed. The observation that all 7 patients with sex reversal share a deletion of the distal short arm of chromosome 9 is consistent with the hypothesis that the region 9p24 contains a gene or genes necessary for male sex determination. This present case narrows the chromosome interval containing a critical sex determination gene to the relatively small region 9p24. A molecular analysis of this region will provide a means to identify a gene involved in male sex determination.