To develop new therapies for inflammatory breast cancer (IBC) we have compared the effects of two hydroxamic acid-based histone deacetylase (HDAC) inhibitors, CG-1521 and Trichostatin A (TSA) on the biology of two IBC cell lines: SUM149PT and SUM190PT. CG-1521 and TSA induce dose (0−10 µM) and time-dependent (0−96 h) increases in the proportion of cells undergoing cell cycle arrest and apoptosis in the presence or absence of 17β-estradiol. In SUM 149PT cells, both CG-1521 and TSA increase the levels of acetylated α-tubulin; however the morphological effects are different: CG-1521 blocks mitotic spindle formation and prevents abscission during cytokinesis while TSA results in an increase in cell size. In SUM190PT cells CG-1521 does not cause an increase in acetylated-α-tubulin and even though TSA significantly increases the levels of acetylated tubulin, neither inhibitor alters the morphology of the cells. Microarray analysis demonstrates that CG-1521 modulates the expression of 876 mRNAs and 63 miRNAs in SUM149PT cells, and 1227 mRNAs and 35 miRNAs in SUM190PT cells. Only 9% of the genes are commonly modulated in both cell lines, suggesting that CG-1521 and TSA target different biological processes in the two cell lines most likely though the inhibition of different HDACs in these cell lines. Gene ontology (GO) analysis reveals that CG-1521 affects the expression of mRNAs that encode proteins associated with the spindle assembly checkpoint, chromosome segregation, and microtubule-based processes in both cell lines and has cell-type specific effects on lipid biosynthesis, response to DNA damage, and cell death.

Previous studies have suggested that 1,25 dihydroxyvitamin D3 (1,25(OH)2D3) induces cell cycle arrest and/or apoptosis in prostate cancer cells in vitro, suggesting that vitamin D may be a useful adjuvant therapy for prostate cancer and a chemopreventive agent. Most epidemiological data however shows a weak link between serum 25(OH)D3 and risk of prostate cancer. To explore dichotomy we have compared tumor progression in the LPB-Tag model of prostate in VDR knock out (VDRKO) and wild type (VDRWT) mice. On the C57BL/6 background LPB-Tag tumors progress significantly more rapidly in the VDRKO mice. VDRKO tumors show significantly higher levels of cell proliferation than VDRWT tumors. In mice supplemented with testosterone to restore the serum levels to the normal range, these difference in tumor progression, and proliferation are abrogated, suggesting that there is considerable cross-talk between the androgen receptor (AR) and the vitamin D axis which is reflected in significant changes in steady state mRNA levels of the AR, PCNA, cdk2 survivin and IGFR1 and 2 genes. These alterations may explain the differences between the in vitro data and the epidemiological studies.

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Purpose: This is the first report of the development and performance of a platform that interrogates small noncoding RNAs (sncRNA) isolated from urinary exosomes. The SentinelÔ PCa Test classifies patients with prostate cancer from subjects with no evidence of prostate cancer, the miR Sentinel CS Test stratifies patients with prostate cancer between those with low risk prostate cancer (Grade Group 1) from those with intermediate and high risk disease (Grade Group 2-5), and the miR Sentinel HG Test stratifies patients with prostate cancer between those with low and favorable intermediate risk prostate cancer (Grade Group 1 or 2) and those with high risk (Grade Group 3-5) disease.Materials and Methods: sncRNAs were extracted from urinary exosomes of 235 participants and interrogated on miR 4.0 microarrays. Using proprietary selection and classification algorithms, informative sncRNAs were selected to customize an interrogation OpenArrayÔ platform that forms the basis of the tests. The tests were validated using a case-control sample of 1,436 subjects. Results:The performance of the miR Sentinel PCa Test demonstrated a sensitivity of 94% and specificity of 92%. The Sentinel CS Test demonstrated a sensitivity of 93% and specificity of 90% for prediction of the presence of Grade Group 2 or greater cancer, and the Sentinel HG Test demonstrated a sensitivity of 94% and specificity of 96% for the prediction of the presence of Grade Group 3 or greater cancer. Conclusions:The Sentinel PCa, CS and HG Tests demonstrated high levels of sensitivity and specificity, highlighting the utility of interrogation of urinary exosomal sncRNAs for noninvasively diagnosing and classifying prostate cancer with high precision.

Iejimalide B, a marine macrolide, causes growth inhibition in a variety of cancer cell lines at nanomolar concentrations. We have investigated the effects of Iejimalide B on cell cycle kinetics and apoptosis in the p53+/AR+ LNCaP and p53-/AR- PC-3 prostate cancer cell lines. Iejimalide B, has a dose and time dependent effect on cell number (as measured by crystal violet assay) in both cell lines. In LNCaP cells Iejimalide B induces a dose dependent G0/G1 arrest and apoptosis at 48 h (as measured by Apo-BrdU staining). In contrast, Iejimalide B initially induces G0/G1 arrest followed by S phase arrest but does not induce apoptosis in PC-3 cells. qPCR and Western analysis suggests that Iejimalide B modulates the steady state level of many gene products associated with cell cycle (including cyclins D, E, and B and p21(waf1/cip1)) and cell death (including survivin, p21B and BNIP3L) in LNCaP cells. In PC-3 cells Iejimalide B induces the expression of p21(waf1/cip1), down regulates the expression of cyclin A, and does not modulate the expression of the genes associated with cell death. Comparison of the effects of Iejimalide B on the two cell lines suggests that Iejimalide B induces cell cycle arrest by two different mechanisms and that the induction of apoptosis in LNCaP cells is p53-dependent.

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Abstract. Histone deacetylase inhibitors are currently being evaluated for their therapeutic potential and have shown considerable promise as adjuvant therapies for a number of cancers. This study compared the effects of 2 hydroxamic acid based inhibitors, CG-1521 and SAHA, on gene expression, cell cycle and cell death in MCF-7 human breast cancer cells. Both compounds show a dose-and time-dependent effect on cell number (evaluated using crystal violet), however CG-1521 exerts its effects significantly earlier than SAHA, and CG-1521 induces apoptosis (assessed by Apo-BrdU staining and flow cytometry) more rapidly than SAHA. qPCR of cell cycle regulatory and apoptotic genes shows that CG-1521 and SAHA modulate similar cohorts of p53-responsive genes, however, the levels of induction and the timing of the induction differs significantly between the 2 inhibitors. In particular SAHA downregulates cell cycle-associated genes that modulate the G 1 /S transition (including cyclin D1 and cdc25a) and the G 2 /M transition [cyclin B1, Plk1, Stk6 (serine-threonine kinase 6, Aurora kinase A) and Kntc2] more significantly than CG-1521. In contrast, CG-1521 significantly induces the expression of several p53 target genes associated with apoptosis including Bnip3/Bnip3L, p21/p21B and Gdf15. The differential levels of gene induction provide molecular evidence of both cell cycle arrest and apoptosis, and suggest a molecular mechanism that explains the difference in the biological effects of the 2 histone deacetylase inhibitors.

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