Sirtuin-1 regulates acinar-to-ductal metaplasia and supports cancer cell viability in pancreatic cancer.

The exocrine pancreas can undergo acinar-to-ductal metaplasia (ADM), as in the case of pancreatitis where precursor lesions of pancreatic ductal adenocarcinoma (PDAC) can arise. The NAD(+)-dependent protein deacetylase Sirtuin-1 (Sirt1) has been implicated in carcinogenesis with dual roles depending on its subcellular localization. In this study, we examined the expression and the role of Sirt1 in different stages of pancreatic carcinogenesis, i.e. ADM models and established PDAC. In addition, we analyzed the expression of KIAA1967, a key mediator of Sirt1 function, along with potential Sirt1 downstream targets. Sirt1 was co-expressed with KIAA1967 in the nuclei of normal pancreatic acinar cells. In ADM, Sirt1 underwent a transient nuclear-to-cytoplasmic shuttling. Experiments where during ADM, we enforced repression of Sirt1 shuttling, inhibition of Sirt1 activity or modulation of its expression, all underscore that the temporary decrease of nuclear and increase of cytoplasmic Sirt1 stimulate ADM. Our results further underscore that important transcriptional regulators of acinar differentiation, that is, Pancreatic transcription factor-1a and ß-catenin can be deacetylated by Sirt1. Inhibition of Sirt1 is effective in suppression of ADM and in reducing cell viability in established PDAC tumors. KIAA1967 expression is differentially downregulated in PDAC and impacts on the sensitivity of PDAC cells to the Sirt1/2 inhibitor Tenovin-6. In PDAC, acetylation of ß-catenin is not affected, unlike p53, a well-characterized Sirt1-regulated protein in tumor cells. Our results reveal that Sirt1 is an important regulator and potential therapeutic target in pancreatic carcinogenesis.

Location and pathological characteristics of cancers in radical prostatectomy specimens identified by transperineal biopsy compared to transrectal biopsy.

PURPOSE: Anterior tumors are estimated to constitute 20% of prostate cancers. Current data indicate that transperineal biopsy is more reliable than transrectal biopsy in identifying these tumors. If correct, this superior reliability should result in an increased proportion of anterior tumors identified by transperineal biopsy. We investigated this hypothesis with reference to prostatectomy specimens. MATERIALS AND METHODS: Radical prostatectomy histopathology records were retrospectively examined. Patients were grouped based on primary transperineal or transrectal biopsy as the modality used to identify the initial cancer. After grouping, tumor location and size were recorded and, thus, the proportion of anterior tumors was determined. RESULTS: A total of 1,132 (414 transperineal and 718 transrectal) prostatectomy specimens were examined. Overall mean tumor size (1.8 and 2.0 cm(3)), stage (pT2 63.3% and 61%) and significance (5.1% and 5.1%) for the transperineal and transrectal methods were similar. However, the transperineal method was associated with proportionally more anterior tumors (16.2% vs 12%, p = 0.046), and identified them at a smaller size (1.4 vs 2.1 cm(3), p = 0.03) and lower stage (extracapsular extension 13% vs 28%, p = 0.03) compared to the transrectal method. The pT3 positive surgical margin rate for anterior vs other tumors was 69% vs 34.9%, respectively. CONCLUSIONS: Overall transrectal and transperineal biopsy identify cancers that are similar in size, stage and significance. However, transperineal biopsy detected proportionally more anterior tumors (16.2% vs 12%), and identified them at a smaller size (1.4 vs 2.1 cm(3)) and stage (extracapsular extension 13% vs 28%) compared to transrectal biopsy. Identifying anterior tumors early is important because the positive surgical margin rate for anterior pT3 lesions is significantly higher.

The hippocampus makes a significant contribution to experience-dependent neocortical plasticity.

Rats received unilateral hippocampal lesions before being placed in complex environments or standard lab housing. Three months later the brains were prepared for Golgi-Cox staining. Pyramidal cells in layer III of parietal cortex were analyzed bilaterally. The basilar dendrites of the parietal pyramidal cells in the intact hemisphere showed the expected changes in experience-dependent changes, including an increase in dendritic branching and length as well as spine density. In contrast, the basilar dendrites of the parietal neurons in the lesion hemisphere showed no significant effect of experience on dendritic branching or length and showed a decrease in spine density in the same neurons. The apical fields failed to show an effect of experience in either hemisphere. The hippocampus plays a crucial role in neocortical experience-dependent plasticity.

Chronic lymphocytic leukemia in the course of chronic myelocytic leukemia: evidence of independent clonal origin as shown by interphase fluorescence in situ hybridization and fluorescence-activated cell sorting.

We report the case of a 57-year-old man who developed chronic lymphocytic leukemia (CLL) several months after the initial diagnosis of Philadelphia (Ph) chromosome-positive (Ph(+)) chronic myelocytic leukemia. CLL cells were purified by using fluorescence-activated cell sorting and further analyzed using interphase fluorescence in situ hybridization with probes to detect the BCR/ABL fusion gene. We provide evidence that the CLL cells arose in a Ph(-) clone.