Cytoplasmic PTEN protein loss distinguishes intraductal carcinoma of the prostate from high-grade prostatic intraepithelial neoplasia

Intraductal carcinoma of the prostate is a marker of aggressive disease. However, intraductal carcinoma exists on a morphologic continuum with high-grade prostatic intraepithelial neoplasia (PIN) and distinguishing intraductal carcinoma from PIN is a common diagnostic dilemma with significant clinical implications. We evaluated whether immunostains for PTEN and ERG can sensitively identify intraductal carcinoma and accurately distinguish it from high-grade PIN. A combined immunostain for PTEN, ERG, p63 and CK903 was developed and validated. Radical prostatectomy specimens with lesions meeting criteria for intraductal carcinoma (n=45), intraductal cribriform proliferations falling short of intraductal carcinoma (n=15), and PIN lesions (n=39) were retrospectively identified and assessed for PTEN and ERG. Cytoplasmic PTEN loss was identified in 84% (38/45) of the intraductal carcinoma and 100% (15/15) of intraductal cribriform proliferation cases. In contrast, cytoplasmic PTEN loss was never observed in PIN (0/39; P<0.0001). Of the 53 cases of intraductal carcinoma or intraductal cribriform proliferation with cytoplasmic PTEN loss, it was homogeneously lost in 42 cases (79%). Weak, focal nuclear positivity for PTEN was retained in 31 of these 42 cases (74%). ERG expression was identified in 58% (26/45) of intraductal carcinoma and 67% (10/15) of intraductal cribriform proliferations compared with 13% (5/39) of PIN. Concordance between the PTEN/ERG status of the intraductal carcinoma lesions and the concurrent invasive carcinoma was high (>95% and P<0.0001 for each), and substantially less for PIN and the concurrent invasive tumor (83% for PTEN and 67% for ERG; P=NS for each). Cytoplasmic PTEN loss occurs in the majority of intraductal carcinoma and intraductal cribriform proliferation cases. Cytoplasmic PTEN loss was never observed in PIN (100% specificity). Our study identifies PTEN loss as a potentially useful marker to distinguish intraductal carcinoma from PIN and provides a plausible molecular explanation for why intraductal carcinoma is associated with poor prognosis.

Colonization of chicken flocks by Campylobacter jejuni in multiple farms in Japan

Campylobacter jejuni was monitored in 4 chicken farms during the period 2003 to 2006 to elucidate the mechanisms of transmission. Three farms (1 to 3), located at least 14 km from each other, belonged to an integrated poultry company, which also provided the farms with day-old chicks from several hatcheries as well as chicken feed. Another farm (4), which belonged to a different company, was located 270 m from farm 1. A total of 206 C. jejuni isolates obtained from the 4 farms were classified into 10 flaA-based RFLP types. Identical RFLP types were found in isolates obtained from chickens originating from multiple hatcheries and reared in different chicken houses on individual farms. Flocks were colonized by strains with 1 or 2 RFLP types in each production cycle, sometimes differing between cycles. Identical RFLP types were found in isolates obtained from the environment around the chicken houses. Using multilocus sequence typing, strains with different RFLP types could be distinguished from each other. Identical RFLP and multilocus sequence typing profiles were found in isolates obtained from farms 1 and 4, and from farms 1 and 2. These results suggest that C. jejuni in these farms comes from common sources external to the farms, even if the farms belong to different companies and obtain chicks from different suppliers.

Requirement of integrin β3 for iron transportation during enamel formation

Rodent incisors exhibit pigmentation on their labial surfaces. Although previous studies have shown that this pigment is composed of iron, the existence of other elements has not been investigated. This study found that the lower incisors of CD61, also known as integrin β3, null mice (CD61(-/-)) lacked pigmentation. Although ameloblasts differentiated and formed enamel normally, no ferric ion accumulation was observed in maturation-stage ameloblasts in CD61(-/-) mice. Surface elements of control and CD61-/- lower incisors were compared by x-ray photoelectron spectroscopy (XPS). XPS analysis detected C, Ca, N, O, and P on the labial surfaces of lower incisors of both mice, whereas Fe was detected only in control samples. No peak of non-ferrous metal or other element was detected in either group. Quantitative RT-PCR analysis of 18 iron-transportation-related genes with mRNA from maturation-stage ameloblasts and ALC, a pre-ameloblastic cell line, was performed. The results suggested that CD61 regulates the expressions of Slc11a2 and Slc40a1, both of which are involved in iron transportation in epithelial tissues. These results suggested that the pigment on the labial surface of mouse incisors is composed of Fe and that both anemia and reduction of iron-transporting proteins may cause the loss of pigmentation in CD61(-/-) mice.

The value of T1-weighted coronal MRI scans in diagnosing occult fracture of the hip

A delay in establishing the diagnosis of an occult fracture of the hip that remains unrecognised after plain radiography can result in more complex treatment such as an arthroplasty being required. This might be avoided by earlier diagnosis using MRI. The aim of this study was to investigate the best MR imaging sequence for diagnosing such fractures. From a consecutive cohort of 771 patients admitted between 2003 and 2011 with a clinically suspected fracture of the hip, we retrospectively reviewed the MRI scans of the 35 patients who had no evidence of a fracture on their plain radiographs. In eight of these patients MR scanning excluded a fracture but the remaining 27 patients had an abnormal scan: one with a fracture of the pubic ramus, and in the other 26 a T1-weighted coronal MRI showed a hip fracture with 100% sensitivity. T2-weighted imaging was undertaken in 25 patients, in whom the diagnosis could not be established with this scanning sequence alone, giving a sensitivity of 84.0% for T2-weighted imaging.

If there is a clinical suspicion of a hip fracture with normal radiographs, T1-weighted coronal MRI is the best sequence of images for identifying a fracture.

Global levels of H3K27me3 track with differentiation in vivo and are deregulated by MYC in prostate cancer

Cancer cells and stem cells share a number of biological characteristics including abundant amounts of decondensed chromatin. However, the molecular correlates and the factors involved in altering chromatin structure in cancer cells are not well known. Here, we report that less differentiated stem-like cells in the basal compartment of human and mouse prostate contain lower levels of the polycomb heterochromatin marker H3K27me3 than more differentiated luminal cells. This link to differentiated normal cells is also found in a number of other human and rodent tissues characterized by hierarchical differentiation. In addition to MYC's traditional role as a gene-specific transcription factor, recent studies indicate that MYC also affects global chromatin structure where it is required to maintain "open" or active chromatin. We now demonstrate that in both MYC-driven prostate cancers in mice and human prostate cancers, global levels of H3K27me3 are reduced in prostatic intraepithelial neoplasia and invasive adenocarcinoma lesions. Moreover, decreased levels of H3K27me3 correlate with increased markers of disease aggressiveness (eg, Gleason score and pathological stage). In vitro, experimentally forced reductions in MYC levels result in increased global levels of H3K27me3. These findings suggest that increased levels of decondensed chromatin in both normal progenitor cells and cancer cells are associated with global loss of H3K27me3, which is linked to MYC overexpression.

First measurement of chiral dynamics in π- γ → π- π- π+

The COMPASS Collaboration at CERN has investigated the π- γ → π- π- π+ reaction at center-of-momentum energy below five pion masses, sqrt[s]<5m(π), embedded in the Primakoff reaction of 190 GeV pions impinging on a lead target. Exchange of quasireal photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, t'<0.001  GeV2/c2. Using partial-wave analysis techniques, the scattering intensity of Coulomb production described in terms of chiral dynamics and its dependence on the 3π-invariant mass m(3π)=sqrt[s] were extracted. The absolute cross section was determined in seven bins of sqrt[s] with an overall precision of 20%. At leading order, the result is found to be in good agreement with the prediction of chiral perturbation theory over the whole energy range investigated.

Post-thymectomy myasthenia gravis with an episode of Osserman stage III

Here, we present the first case of post-thymectomy Myasthenia Gravis with onset at Osserman stage III. An 81-year-old woman was admitted for an abnormal shadow seen in a chest radiograph. She had no symptoms of Myasthenia Gravis. Acetylcholine receptor antibody was within the normal range. Chest computed tomography (CT) showed a bulky anterior mediastinal tumor. She was diagnosed as having thymoma by tissue biopsy under CT guidance. The tumor was completely resected by performing thymothymectomy, left upper lobectomy, pericardial resection, and phrenicectomy. Pathological examination of the tumor identified it as a thymoma (type B2, Masaoka stage II). Two months after the surgery, she experienced the onset of post-thymectomy myasthenia gravis with Osserman stage III. The acetylcholine receptor antibody level was remarkably elevated (220 nmol/L); however, there was no evidence of tumor recurrence.

Myc enforces overexpression of EZH2 in early prostatic neoplasia via transcriptional and post-transcriptional mechanisms

EZH2 is part of the PRC2 polycomb repressive complex that is overexpressed in multiple cancer types and has been implicated in prostate cancer initiation and progression. Here, we identify EZH2 as a target of the MYC oncogene in prostate cancer and show that MYC coordinately regulates EZH2 through transcriptional and post-transcriptional means. Although prior studies in prostate cancer have revealed a number of possible mechanisms of EZH2 upregulation, these changes cannot account for the overexpression EZH2 in many primary prostate cancers, nor in most cases of high grade PIN. We report that upregulation of Myc in the mouse prostate results in overexpression of EZH2 mRNA and protein which coincides with reductions in miR-26a and miR-26b, known regulators of EZH2 in some non-prostate cell types, albeit not in others. Further, in human prostate cancer cells, Myc negatively regulates miR-26a and miR-26b via direct binding to their parental Pol II gene promoters, and forced overexpression of miR-26a and miR-26b in prostate cancer cells results in decreased EZH2 levels and suppressed proliferation. In human clinical samples, miR-26a and miR-26b are downregulated in most primary prostate cancers. As a separate mechanism of EZH2 mRNA upregulation, we find that Myc binds directly to and activates the transcription of the EZH2 promoter. These results link two major pathways in prostate cancer by providing two additional and complementary Myc-regulated mechanisms by which EZH2 upregulation occurs and is enforced during prostatic carcinogenesis. Further, the results implicate EZH2-driven mechanisms by which Myc may stimulate prostate tumor initiation and disease progression.

Abstract 73: The transfection of high mobility group protein AT-hook 1 (HMGA1) is associated with the development of androgen independency in prostate cancer cells

The level of HMGA1 is low in androgen-dependent prostate cancer cell line (LNCaP), but is high in androgen-independent prostate cancer cell lines (DU145, PC-3). We have reported that the level of HMGA1 expression in prostate cancer cells is correlated with the extent of chromosomal aberrations (Can Res, 2002) and that transfection of HMGA1 into prostate cancer cell lines induces unbalanced chromosomal rearrangement and expression of matrix metalloproteinase 2 (Prostate, 2004). This suggests that HMGA1 is a strong candidate gene playing a potential role in the progression of prostate cancer. These findings have prompted us to evaluate the effect of HMGA1 on androgen independency, which is associated with the progression of prostate cancer. The androgen-dependent LNCaP cell line was induced to an androgen-independent subline (LN95) by being maintained for long term in the absence of androgen. The absence of androgen induced a 2.5-fold increase in the level of HMGA1 in the LN95 cell line. Androgen deprivation in vitro for 4 days as well as that for 8 days in vivo induced significant increase in the level of HMGA1 in parental LNCaP. On the other hand, the level of HMGA1 in normal prostate of mice 4 days and 11 days after castration as well as sham operation was almost undetectable. The cell proliferation rates of LNCaP cell transfected with HMGA1a vector (LN-H1) and LNCaP cell transfected with control empty vector (LN-EV) were determined with various concentrations (0-1nM) of dihydrotestosterone (DHT) by WST-8 assay in order to examine the effect of HMGA1 on androgen sensitivity. The expression of HMGA1 protein in LNH1 was confirmed to be 3.2-fold as high as that in LNEV. In low concentration (0-0.01 nM) of DHT, LNEV cell could not keep proliferation over day 6, while LNH1 could maintain proliferation over day 6. The cell proliferation rate at day 8 of LN-H1 grown in low concentration (0-0.01 nM) of DHT was about 2-fold higher than that of LN-EV. In contrast, both LN-H1 and LN-EV cells grew equally well in higher concentrations (0.1-1 nM) of DHT and could also keep proliferation over day6. Suppression of HMGA1 in DU145 and PC-3 by siRNA decreased cell proliferation rate and colony formation ability by 40% and 10-fold, respectively, in androgen-deprived medium. These data suggest that HMGA1 is associated with the transition of prostate cancer cells from androgen-sensitive to androgen-independent growth and plays a role in the cell growth of androgen-independent prostate cancer cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 73. doi:1538-7445.AM2012-73

Abstract 2210: Global levels of H3K27me3 track with differentiation in vivo and are deregulated by MYC in prostate cancer

Both embryonic stem cells and various cancer cell types contain abundant amounts of decondensed chromatin. However, the molecular mechanisms responsible for altering chromatin states in stem cells and cancer cells are not well understood. One factor may be the oncogenic transcription factor, MYC. MYC is overexpressed in many tumor types and affects a wide array of essential cellular processes including ribosome and mitochondrial biogenesis, metabolism, and cell cycle progression. MYC is also a key factor in reprogramming of somatic adult cells into induced pluripotent stem cells. Less well known is that MYC also affects global chromatin structure where it is required to maintain open or active chromatin. We hypothesize that in prostate cancer, MYC affects global chromatin structure keeping it in a more open conformation thus maintaining the cells in a less differentiated state resembling that of stem cells. We show by immunohistochemistry that compared to the more differentiated luminal cells, less differentiated stem-like cells in the basal compartment of the human and mouse prostate contain lower levels of the polycomb heterochromatin mark, H3K27me3. This link to the differentiated state of normal cells is also found in a number of other human and rodent tissues characterized by hierarchical differentiation and rapid turnover of stem cell compartments. Further, in MYC-driven prostate cancers in mice, global levels of H3K27me3 are reduced in both prostatic intraepithelial neoplasia (PIN) and invasive adenocarcinoma lesions. This pattern of global H3K27me3 reduction in PIN and invasive prostate cancers is also observed in humans, correlates with global chromatin decondensation, and correlates with increased markers of disease aggressiveness (e.g. Gleason score and pathological stage). In prostate and breast cancer cells, experimentally forced reductions in MYC levels result in increased global levels of H3K27me3. These findings suggest that increased levels of decondensed chromatin in normal stem/progenitor cells and in cancer cells are associated with global loss of the H3K27me3 polycomb mark, and furthermore, MYC overexpression could be one mechanism for this H3K27me3 deregulation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2210. doi:1538-7445.AM2012-2210

Skeletal events unrelated to bone metastasis in men with castration-refractory prostate cancer

85

Background: The purpose of this study was to analyze skeletal events unrelated to bone metastasis in men with castration-refractory prostate cancer (CRPC).

Methods: A total of 68 patients with CRPC treated by secondary hormonal therapy (dexamethasone) and/or chemotherapy including docetaxel were analyzed. Primary endpoint was skeletal related events (SREs) after PSA relapse. PSA relapse was defined as 3 consecutive PSA increase and serum PSA more than 4 ng/ml. Zoledronic acid was given for 31 patients with radiographic bone progression from the initiation of docetaxel-based treatment. For 37 patients without radiographic bone progression, no bone targeted agents or radioisotopes were administered during the observation period.

Results: During median observation period of 17.5 months (range 1 to 76 months), SREs were observed in 17 of 68 patients (25%). In patients with bone progression, SREs was observed in 8 of 37 (22%) patients, whereas 9 of 31 (29%) patients without radiographic bone progression experienced SREs unrelated to bone metastasis. All patients without radiographic progression had been treated by oral steroids (dexamethasone), which might be related to osteoporotic change in these cases.

Conclusions: For CRPC patients without radiographic bone progression, caution needs to be paid for SRE unrelated to bone metastasis. The administration of steroids may cause osteoporotic change, thus preventive administration of anti-osteoporotic agents would be mandatory.

Use of radiographic progression to predict overall survival in men with castration-refractory prostate cancer

254

Background: The purpose of this study was to analyze prognostic factors to predict overall survival in patients with castration-refractory prostate cancer (CRPC).

Methods: A total of 68 patients with CRPC treated by secondary hormonal therapy (dexamethasone) and/or chemotherapy including docetaxel were analyzed. Primary endpoint was survival after PSA relapse. PSA relapse was defined as 3 consecutive PSA increase and serum PSA more than 4 ng/ml. Factors analyzed to predict survival were initial PSA value, initial clinical stage, pathological tumor grade (WHO grade), time to PSA relapse, nadir PSA value, time to nadir PSA, age at PSA relapse, PSA value at relapse, radiographic progression revealed by bone scan or CT scan, and bone pain. Univariate and multivariate analysis were performed using Cox regression hazard model.

Results: Univariate analysis revealed nadir PSA value, time to nadir PSA, PSA value at relapse, radiographic progression revealed by bone scan or CT scan, and bone pain were significant predictors (p<0.05). Multivariate analysis revealed only radiographic progression was the independent predictor for survival after PSA relapse (p=0.039). Median survival time was 63.5 and 23.5 months in patients with (n=39) and without (n=29) radiographic progression, respectively (log-rank p=0.0002). Median survival time in 39 patients with radiographic progression in bone (n=31), lymph nodes (n=6), visceral lesion (n=3), and local lesion (n=4) were 23.5, 5, 2, and 12.5 months, respectively.

Conclusions: For patients with PSA relapse after hormonal therapy, the finding of radiographic progression was the only independent factor to predict overall survival.

Differential epithelium DNA damage response to ATM and DNA-PK pathway inhibition in human prostate tissue culture

The ability of cells to respond and repair DNA damage is fundamental for the maintenance of genomic integrity. Ex vivo culturing of surgery-derived human tissues has provided a significant advancement to assess DNA damage response (DDR) in the context of normal cytoarchitecture in a non-proliferating tissue. Here, we assess the dependency of prostate epithelium DDR on ATM and DNA-PKcs, the major kinases responsible for damage detection and repair by nonhomologous end-joining (NHEJ), respectively. DNA damage was caused by ionizing radiation (IR) and cytotoxic drugs, cultured tissues were treated with ATM and DNA-PK inhibitors, and DDR was assessed by phosphorylation of ATM and its targets H2AX and KAP1, a heterochromatin binding protein. Phosphorylation of H2AX and KAP1 was fast, transient and fully dependent on ATM, but these responses were moderate in luminal cells. In contrast, DNA-PKcs was phosphorylated in both luminal and basal cells, suggesting that DNA-PK-dependent repair was also activated in the luminal cells despite the diminished H2AX and KAP1 responses. These results indicate that prostate epithelial cell types have constitutively dissimilar responses to DNA damage. We correlate the altered damage response to the differential chromatin state of the cells. These findings are relevant in understanding how the epithelium senses and responds to DNA damage.