Citations

Abstract Alterations in nuclear structure distinguish cancer cells from noncancer cells. These nuclear alterations can be translated into quantifiable features by digital image analysis in a process known as quantitative nuclear morphometry. Recently, quantitative nuclear morphometry has been shown to predict metastasis and biochemical recurrence of prostate cancer. However, little is known about the cellular mechanisms underlying these nuclear morphometric changes. Alterations of nuclear matrix proteins are frequently involved in changes of nuclear structure. A number of co-activators interact with these nuclear structure–related proteins, suggesting that they might be involved in quantitative nuclear morphometry changes. We have shown previously that the transcriptional co-activator p300 is involved in prostate cancer progression. However, the ability of a transcriptional regulator like p300 to modulate nuclear morphology has not been described previously. In the present study, we show that p300 expression in prostate cancer biopsy tissue from 95 patients correlates with quantifiable nuclear alterations. Moreover, we show that transfection of p300 into prostate cancer cells in culture induces quantifiable nuclear alterations, such as diameter, perimeter, and absorbance among others, as assessed by digital image analysis. These alterations correlate individually with aggressive features in prostate cancer, such as expression of the proliferation marker Ki-67 and extraprostatic extension of the tumor. Finally, we found that transfection of p300 into prostate cancer cells specifically increases mRNA and protein levels of nuclear matrix peptides lamins A and C, suggesting that these proteins mediate the p300-induced effects. These findings reveal a new insight into the transcriptional and structural regulation of prostate cancer.

Abstract Prostate cancer is the most prevalent malignancy and the second leading cause of cancer mortality in men. Early growth response gene-1 (EGR-1) plays a crucial role in the development and progression of prostate cancer. The presented data show that EGR-1 differs in cellular localization in benign cells compared with malignant prostate cells and that this localization is critical for the transcriptional activation of EGR-1-dependent genes. Immunohistochemistry of human prostate cancer specimens demonstrated higher levels of EGR-1 in malignant cells located predominantly in the cytoplasm, whereas benign cells contained lower levels of EGR-1 located predominantly in the nucleus. Benign prostate cells responded to mitogens in vitro, with increased levels of EGR-1, rapid nuclear translocation, and enhanced transcriptional activity, whereas malignant prostate cells did not exhibit the same responses, and the protein remained in the cytoplasm. The central aspect of this difference is the association of EGR-1 with microtubules, which is exclusive to the benign cells of the prostate and is requisite for the nuclear translocation and transcriptional activity of EGR-1. Our in vitro data demonstrate that the differences in EGR-1 between benign and malignant prostate cells extend beyond cellular levels, which was confirmed by immunohistochemistry in human tissues. Thus, we add the novel concept that microtubules regulate EGR-1 localization in benign prostate cells but not in malignant prostate cells.

AbstractBackground: Human glandular kallikrein (hK2) is a serine protease that has 79% amino acid identity with prostate-specific antigen (PSA). Both free hK2 and hK2 complexed to α1-antichymotrypsin (ACT) are present in the blood in low concentrations. We wished to measure hK2 in serum with limited contribution from hK2-ACT for the results.Methods: We developed an automated assay for hK2 with use of a select pair of monoclonal antibodies. The prototype assay was implemented on a Beckman Coulter ACCESS® analyzer.Results: The detection limit of the assay was 1.5 ng/L, the “functional sensitivity” (day-to-day CV <15%) was <4 ng/L, cross-reactivity with PSA and PSA-ACT was negligible, and cross-reactivity with hK2-ACT was 2%. After surgical removal of prostate glands, serum hK2 was <7 ng/L and was <15 ng/L in most healthy women. The median serum concentration of hK2 in healthy men without prostate cancer was 26 ng/L. The median concentration of hK2 was 72 ng/L for men having prostate cancer with lower Gleason scores compared with 116 ng/L for men with more advanced cancer. The concentration of hK2 correlated weakly with PSA, with the mean hK2 concentrations generally 30- to 80-fold lower than PSA concentrations.Conclusion: The availability of a robust, high sensitivity automated assay for hK2 should facilitate further investigations of the role of hK2 measurements in the management of patients with prostate disease.

Background: Although 50% to 90% of patients who receive epidermal growth factor receptor (EGFR) inhibitors develop a rash, options for rash prevention or palliation remain limited. This issue is particularly important from a palliative care standpoint because these agents are prescribed only to patients with incurable cancer. Here, we report (1) gene expression profiling of skin biopsies from patients with an EGFR inhibitor–induced rash and (2) a randomized, placebo-controlled feasibility trial with the antiandrogen, spironolactone. Both investigations were undertaken to begin to explore the hypothesis that androgens mediate EGFR inhibitor–induced rash and that antiandrogens palliate it. Methods/Results: First, 4 skin biopsies from patients with EGFR inhibitor–induced rash (3 men and 1 woman) were subject to gene expression microarray profiling. A public data set of normal skin gene expression (Gene Expression Omnibus, GSE22998) served as a reference. Sixty percent of commonly interrogated androgen receptor genes (207 of 308 between the 2 data sets) were differentially expressed ( P < .05) in the rash samples. Second, in a 17-patient double-blinded, placebo-controlled trial with topical spironolactone applied to the face, although the primary feasibility end point was not achieved, patients in the spironolactone arm received more doses of EGFR inhibitor, and anecdotal photographic evidence suggested salutatory effects of spironolactone on rash. Conclusions: Epidermal growth factor receptor inhibitor–induced rash appears to be androgen-mediated; antiandrogen therapy merits further study for rash prevention/palliation.