Project description:Background: Prostate cancer (PCa) cells preferentially metastasize to bone at least in part by acquiring osteomimetic properties. Runx2, an osteoblast master transcription factor, is aberrantly expressed in PCa cells, and promotes their metastatic phenotype. The transcriptional programs regulated by Runx2 have been extensively studied during osteoblastogenesis, where it activates or represses target genes in a context-dependent manner. However, little is known about the gene regulatory networks influenced by Runx2 in PCa cells. We therefore investigated genome-wide mRNA expression changes in PCa cells in response to Runx2. Results: We engineered a C4-2B PCa sub-line called C4-2B/Rx2dox, in which doxycycline (Dox) treatment stimulates Runx2 expression from very low levels to levels observed in other PCa cells. Transcriptome profiling using whole genome expression array followed by in silico analysis indicated that Runx2 upregulated a multitude of genes with prominent cancer-associated functions. They included secreted factors (CSF2, SDF-1), proteolytic enzymes (MMP9, CST7), cytoskeleton modulators (SDC2, Twinfilin, SH3PXD2A), intracellular signaling molecules (DUSP1, SPHK1, RASD1) and transcription factors (Sox9, SNAI2, SMAD3) functioning in epithelium to mesenchyme transition (EMT), tissue invasion, as well as homing and attachment to bone. Consistent with the gene expression data, induction of Runx2 in C4-2B cells enhanced their invasiveness. It also promoted cellular quiescence by blocking the G1/S phase transition during cell cycle progression. Furthermore, the cell cycle block was reversed as Runx2 levels declined after Dox withdrawal. Conclusions: The effects of Runx2 in C4-2B/Rx2dox cells, as well as similar observations made by employing LNCaP, 22RV1 and PC3 cells, highlight multiple mechanisms by which Runx2 promotes the metastatic phenotype of PCa cells, including tissue invasion, homing to bone and induction of high bone turnover. Runx2 is therefore an attractive target for the development of novel diagnostic, prognostic and therapeutic approaches to PCa management. Targeting Runx2 may prove more effective than focusing on its individual downstream genes and pathways. C4-2B/Rx2dox cells were subjected to microarray gene expression analysis after one and two days of treatment with either Dox or vehicle in biological quadruplicates (a total of 16 samples).

Project description:The estrogen receptor (ER)M-NM-21 is successively lost during cancer progression, whereas its splice variant, ERM-NM-22, is expressed in advanced prostate cancer. The latter form of cancer often metastasizes to bone, and we wanted to investigate whether the loss of ERM-NM-21 and/or the expression of ERM-NM-22 affect such signaling pathways in prostate cancer. Using PC3 and 22Rv1 prostate cancer cell lines that stably express ERM-NM-21 or ERM-NM-22, we found that the ERM-NM-2 variants differentially regulate genes known to affect tumor behavior. We found that ERM-NM-21 repressed the expression of the bone metastasis regulator Runx2 in PC3 cells. By contrast, RUNX2 expression was up-regulated at the mRNA level by ERM-NM-22 in PC3 cells, whereas Slug was up-regulated by ERM-NM-22 in both PC3 and 22Rv1 cells. In addition, the expression of Twist1, a factor whose expression strongly correlates with high Gleason grade prostate carcinoma, was increased by ERM-NM-22. In agreement with the increased Twist1 expression, we found increased expression of Dickkopf homolog 1; Dickkopf homolog 1 is a factor that has been shown to increase the RANK ligand/osteoprotegerin ratio and enhance osteoclastogenesis, indicating that the expression of ERM-NM-22 can cause osteolytic cancer. Furthermore, we found that only ERM-NM-21 inhibited proliferation, whereas ERM-NM-22 increased proliferation. The expression of the proliferation markers Cyclin E, c-Myc, and p45(Skp2) was differentially affected by ERM-NM-21 and ERM-NM-22 expression. In addition, nuclear M-NM-2-catenin protein and its mRNA levels were reduced by ERM-NM-21 expression. In conclusion, we found that ERM-NM-21 inhibited proliferation and factors known to be involved in bone metastasis, whereas ERM-NM-22 increased proliferation and up-regulated factors involved in bone metastasis. Thus, in prostate cancer cells, ERM-NM-22 has oncogenic abilities that are in strong contrast to the tumor-suppressing effects of ERM-NM-21. The GFP vs. ERbeta1 comparison was carried out with three replicate dye-swaps, six arrays total. The GFP vs. ERbeta2 comparison was carried out with two replicate dye-swaps, four arrays total.

Project description:Background: Prostate cancer (PCa) cells preferentially metastasize to bone at least in part by acquiring osteomimetic properties. Runx2, an osteoblast master transcription factor, is aberrantly expressed in PCa cells, and promotes their metastatic phenotype. The transcriptional programs regulated by Runx2 have been extensively studied during osteoblastogenesis, where it activates or represses target genes in a context-dependent manner. However, little is known about the gene regulatory networks influenced by Runx2 in PCa cells. We therefore investigated genome-wide mRNA expression changes in PCa cells in response to Runx2. Results: We engineered a C4-2B PCa sub-line called C4-2B/Rx2dox, in which doxycycline (Dox) treatment stimulates Runx2 expression from very low levels to levels observed in other PCa cells. Transcriptome profiling using whole genome expression array followed by in silico analysis indicated that Runx2 upregulated a multitude of genes with prominent cancer-associated functions. They included secreted factors (CSF2, SDF-1), proteolytic enzymes (MMP9, CST7), cytoskeleton modulators (SDC2, Twinfilin, SH3PXD2A), intracellular signaling molecules (DUSP1, SPHK1, RASD1) and transcription factors (Sox9, SNAI2, SMAD3) functioning in epithelium to mesenchyme transition (EMT), tissue invasion, as well as homing and attachment to bone. Consistent with the gene expression data, induction of Runx2 in C4-2B cells enhanced their invasiveness. It also promoted cellular quiescence by blocking the G1/S phase transition during cell cycle progression. Furthermore, the cell cycle block was reversed as Runx2 levels declined after Dox withdrawal. Conclusions: The effects of Runx2 in C4-2B/Rx2dox cells, as well as similar observations made by employing LNCaP, 22RV1 and PC3 cells, highlight multiple mechanisms by which Runx2 promotes the metastatic phenotype of PCa cells, including tissue invasion, homing to bone and induction of high bone turnover. Runx2 is therefore an attractive target for the development of novel diagnostic, prognostic and therapeutic approaches to PCa management. Targeting Runx2 may prove more effective than focusing on its individual downstream genes and pathways.

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Homo sapiens

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