Photoinduced decarboxylative germylation of α-fluoroacrylic acids: access to germylated monofluoroalkenes.

Herein, a novel strategy is presented for the photoinduced decarboxylative and dehydrogenative cross-coupling of a wide range of α-fluoroacrylic acids with hydrogermanes. This methodology provides an efficient and robust approach for producing various germylated monofluoroalkenes with excellent stereoselectivity within a brief photoirradiation period. The feasibility of this reaction has been demonstrated through gram-scale reaction, conversion of germylated monofluoroalkenes, and modification of complex organic molecules.

Photoinduced Decarboxylative Difluoroalkylation and Perfluoroalkylation of α-Fluoroacrylic Acids.

Herein, a novel and practical methodology for the photoinduced decarboxylative difluoroalkylation and perfluoroalkylation of α-fluoroacrylic acids is reported. A wide range of α-fluoroacrylic acids can be used as applicable feedstocks, allowing for rapid access to structurally important difluoroalkylated and polyfluoroalkylated monofluoroalkenes with high Z-stereoselectivity under mild conditions. The protocol demonstrates excellent functional group compatibility and provides a platform for modifying complex biologically active molecules.

SCARNA10 regulates p53 acetylation-dependent transcriptional activity.

The tumor suppressor p53 is involved in variety of cell progresses including cell cycle arrest, apoptosis, DNA repair, senescence, cell metabolism and ferroptosis. Here, we identified lncRNA SCARNA10 (Small Cajal Body-Specific RNA 10) as a novel cellular factor that interacts with the DNA binding domain (DBD) of p53. Upon binding the DBD of p53 and CREB-binding protein (CBP), SCARNA10 promotes the acetylation of p53, and activates p53-mediated transcriptional activation. Overexpress or knockdown SCARNA10 leads to up (or down)-regulation of p53-mediated transcriptional activation, whereas not affecting p53 protein levels. Moreover, SCARNA10 directly activates transcription by increasing the acetylation of p53 C-terminal domain (CTD) without affecting p53 phosphorylation at Ser15. These results indicate that SCARNA10 is a novel factor which regulates p53 acetylation-dependent transcriptional activity and tumor suppression.

Dexamethasone inhibits TGF-ß2-induced migration of human lens epithelial cells: implications for posterior capsule opacification prevention.

The elevation of transforming growth factor-ß2 (TGF-ß2) levels in eye tissue is considered as one of the major factors contributing to posterior capsule opacification (PCO) in patients undergoing cataract surgery, since TGF-ß2 is known to stimulate the cell migration of residual human lens epithelial cells (HLECs). The present study aimed to test the potential effect of dexamethasone (DEX) on TGF-ß2-induced cell migration and the possible cellular mechanisms involved in this process. Cultured HLE-B3 cells were treated with TGF-ß2 (0.1 ng/ml) in the presence or absence of DEX (100 nM). HLE-B3 cell migration was determined by the Phagokinetic Track Motility Assay. Activation of mitogen-activated protein kinase (MAPK) signaling pathways was determined by Western blotting using specific phosphorylation antibodies, matrix metalloproteinase (MMP)-2 and MMP-9 mRNA expression, and activities were analyzed by RT-PCR and gelatin zymography assay, respectively. In cultured HLE-B3 cells, DEX largely inhibited TGF-ß2-induced cell migration and MMP activity, probably by inhibiting the ERK/MAPK pathway. We suggest that the use of DEX may be of help in the prevention of PCO formation and development.

CD26/dipeptidyl peptidase IV regulates prostate cancer metastasis by degrading SDF-1/CXCL12.

Stromal derived factor-1 (SDF-1 or CXCL12) expressed by osteoblasts and endothelial cells, and its receptors CXCR4 and CXCR7/RDC1 are key molecular determinants in prostate cancer (PCa) metastasis. What drives PCa cells into the extravascular marrow space(s) once they make contact with the blood vessel endothelium, however remains unclear. Here, we evaluated whether degradation of CXCL12 facilitates PCa cell entry into the marrow cavity by locally lowering CXCL12 levels intravascularly. To explore this possibility, co-cultured conditioned media from PCa cells and endothelial cells were evaluated for their ability to degrade biotinylated CXCL12 (bCXCL12). Co-culture of PCa cells/endothelial cells resulted in greater digestion of CXCL12 than was achieved by either cell type alone, and this activity regulated invasion in vitro. The ability to degrade CXCL12 was not however observed in PCa and osteoblasts co-cultures. Fractionation and inhibitor studies suggested that the activity was CD26/dipeptidyl peptidase IV (DPPIV) and possibly other cysteine/serine proteases. By inhibiting CD26/DPPIV, invasion and metastasis of PCa cell lines were enhanced in in vitro and in vivo metastasis assays. Together, these data suggest that the degradation of CXCL12 by CD26/DPPIV may be involved in the metastatic cascades of PCa, and suggests that inhibition of CD26/DPPIV may be a trigger of PCa metastasis.

An in vivo mouse model for human prostate cancer metastasis.

We developed a sensitive real-time polymerase chain reaction (QPCR) assay that allows us to track early lodging/homing events in vivo. We used this technology to develop a metastasis assay of human prostate cancer (PCa) growth in severe combined immunodeficient mice. For this purpose, marked human PCa cell lines were implanted subcutaneously or in the prostate (orthotopically) of severe combined immunodeficient mice as models of primary tumors. Mice were then sacrificed at various time points, and distant tissues were investigated for the presence of metastatic cells. At 3 weeks, a number of tissues were recovered and evaluated by QPCR for the presence of metastatic cells. The data demonstrate that several PCa cell lines are able to spread from the primary lesion and take up residence in distant sites. If the primary tumors were resected at 3 weeks, in several cases, metastatic lesions were identified over the course of 9 months. We propose that this new model may be particularly useful in exploring the molecular events in early metastasis, identifying the metastatic niche, and studying issues pertaining to dormancy.

Annexin II expressed by osteoblasts and endothelial cells regulates stem cell adhesion, homing, and engraftment following transplantation.

Differentiation of hematopoietic stem cells (HSCs) after birth is largely restricted to the bone marrow cavity, where HSCs are associated closely with osteoblasts (OBs). How OBs localize HSCs to the endosteal niche remains unclear. To explore adhesive interactions between HSCs and OBs, a cell blot analysis was used that revealed 2 major bands that corresponded to monomers and multimers of annexin II (Anxa2). Immunohistochemistry revealed that OBs and marrow endothelial cells express Anxa2 at high levels. Function-blocking studies confirmed that Anxa2 mediates HSC adhesion mainly via the N-terminal portion of the Anxa2 peptide. Adhesion of HSCs to OBs derived from Anxa2-deficient animals (Anxa2(-/-)) was significantly impaired compared with OBs obtained from wild-type animals (Anxa2(+/+)). Moreover, fewer HSCs were found in the marrow of Anxa2(-/-) versus Anxa2(+/+) animals. Short-term lodging, engraftment, and survival of irradiated mice with whole marrow cells were substantially inhibited by N-terminal peptide fragments of Anxa2 or anti-Anxa2 antibodies. Similar findings were noted in long-term competitive repopulation studies. Collectively, these findings reveal that Anxa2 regulates HSC homing and binding to the bone marrow microenvironment and suggest that Anxa2 is crucial for determining the bone marrow niche of HSCs.

Expression and activation of alpha v beta 3 integrins by SDF-1/CXC12 increases the aggressiveness of prostate cancer cells.

BACKGROUND: Stromal cell-derived factor-1 (SDF-1 or CXCL12) and CXCR4 are key elements in the metastasis of prostate cancer cells to bone--but the mechanisms as to how it localizes to the marrow remains unclear. METHODS: Prostate cancer cell lines were stimulated with SDF-1 and evaluated for alterations in the expression of adhesion molecules using microarrays, FACs, and Western blotting to identify alpha(v)beta(3) receptors. Cell-cell adhesion and invasion assays were used to verify that activation of the receptor is responsive to SDF-1. RESULTS: We demonstrate that SDF-1 transiently regulates the number and affinity of alpha(v)beta(3) receptors by prostate cancer cells to enhance their metastatic behavior by increasing adhesiveness and invasiveness. SDF-1 transiently increased the expression of beta(3) receptor subunit and increased its phosphorylation in metastatic but not nonmetastatic cells. CONCLUSIONS: The transition from a locally invasive phenotype to a metastatic phenotype may be primed by the elevated expression of alpha(v)beta(3) receptors. Activation and increased expression of alpha(v)beta(3) within SDF-1-rich organs may participate in metastatic localization.

Cell-to-cell contact is critical for the survival of hematopoietic progenitor cells on osteoblasts.

Osteoblasts constitute part of the stromal cell support system in marrow for hematopoiesis, however little is known as to how they interact with hematopoietic stem cells (HSCs). In vitro studies have demonstrated that the survival of HSCs in co-culture with osteoblasts requires intimate cell-to-cell contact. This suggests that the osteoblast-derived factor(s) that supports stem cell activities are produced in very small quantities, are rapidly turned over, may be membrane-anchored and/or require the engagement of cell-cell adhesion molecules that are yet to be determined. In the present report we found that the survival of hematopoietic progenitor cells on osteoblasts is dependent upon the engagement of VLA-4 (alpha4beta1) and VLA-5 (alpha5beta1) receptors using function blocking antibodies. Cell-to-cell contact is required to support progenitor activity, but can be replaced if receptor-ligand engagement of the VLA-4 and LFA-1 complexes is provided through the use of recombinant ligands (fibronectin, ICAM-1, VCAM-1). Moreover, once these receptors were engaged, conditioned medium derived from HSCs grown on osteoblast ligands supported significantly greater hematopoietic progenitors in vitro than did osteoblast-conditioned or HSC-conditioned medium alone. While the molecules present in the co-cultured medium remain to be identified, the data suggest that hematopoietic cells cooperate with osteoblasts to assemble the various marrow microenvironments by directing the synthesis of osteoblast-derived cytokines to improve HSC survival.

Diverse signaling pathways through the SDF-1/CXCR4 chemokine axis in prostate cancer cell lines leads to altered patterns of cytokine secretion and angiogenesis.

The establishment of metastatic bone lesions in prostate cancer (CaP) is a process partially dependent on angiogenesis. Previously we demonstrated that the stromal-derived factor-1 (SDF-1 or CXCL12)/CXCR4 chemokine axis is critical for CaP cell metastasis. In this investigation, cell lines were established in which CXCR4 expression was knocked down using siRNA technology. When CaP cells were co-transplanted with human vascular endothelial cells into SCID mice, significantly fewer human blood vessels were observed paralleling the reductions in CXCR4 levels. Likewise, the invasive behaviors of the CaP cells were inhibited in vitro. From these functional observations we explored angiogenic and signaling mechanisms generated following SDF-1 binding to CXCR4. Differential activation of the MEK/ERK and PI3K/AKT pathways that result in differential secretion IL-6, IL-8, TIMP-2 and VEGF were seen contingent on the cell type examined; VEGF and TIMP-2 expression in PC3 cells are dependent on AKT activation and ERK activation in LNCaP and LNCaP C4-2B cells leads to IL-6 or IL-8 secretion. At the same time, expression of angiostatin levels were inversely related to CXCR4 levels, and inhibited by SDF-1 stimulation. These data link the SDF-1/CXCR4 pathway to changes in angiogenic cytokines by different signaling mechanisms and, suggest that the delicate equilibrium between proangiogenic and antiangiogenic factors may be achieved by different signal transduction pathways to regulate the angiogenic phenotype of prostate cancers. Taken together, our results provide new information regarding expression of functional CXCR4 receptor-an essential role and potential mechanism of angiogenesis upon SDF-1 stimulation.

Unilateral spinal nerve ligation leads to an asymmetrical distribution of mast cells in the thalamus of female but not male mice.

Mast cells are restricted to the leptomeninges and thalamus of healthy mice. These populations are increased by stress and highly sensitive to reproductive hormones. To examine the influence of nociception, a form of stress, on thalamic mast cells, we ligated the left fifth lumbar spinal nerve of male and female mice to induce hyperalgesia. Two, 7 and 14 days later, mice were killed and thalami examined histologically using toluidine blue stain. The total number of thalamic mast cells was not influenced by ligation of the spinal nerve compared to sham-operation in either female or male mice. However, in females, the percent of thalamic mast cells located on the side of the thalamus contralateral to the ligation was greater on days 2 and 7, coincident with mechanical hyperalgesia. At these times, areas in which mast cells were most dense contralateral to nerve-injury included the posterior (Po) and lateral geniculate (LG) nuclei compared to their symmetrical distribution in sham-operated mice. These data suggest that local nociceptive signals to each side of the thalamus rather than stress hormones influence the location of mast cells during the development of allodynia and hyperalgesia. In addition, both hyperalgesia and mast cell distribution induced by nerve-ligation differ in females compared to males, reflecting a novel neuroimmune response to pain within the CNS.

Skeletal localization and neutralization of the SDF-1(CXCL12)/CXCR4 axis blocks prostate cancer metastasis and growth in osseous sites in vivo.

UNLABELLED: To delineate the role of SDF-1 and CXCR4 in metastatic prostate cancer (CaP), positive correlations were established between SDF-1 levels and tumor metastasis. Neutralization of CXCR4 limited the number and the growth of intraosseous metastasis in vivo. Together, these in vivo metastasis data provide critical support that SDF-1/CXCR4 plays a role in skeletal metastasis. INTRODUCTION: Previously we determined that the stromal-derived factor-1 (SDF-1)/CXCR4 chemokine axis is activated in prostate cancer (CaP) metastasis to bone. To delineate the role of SDF-1/CXCR4 in CaP, we evaluated SDF-1 levels in a variety of tissues and whether neutralization of SDF-1 prevented metastasis and/or intraosseous growth of CaPs. MATERIALS AND METHODS: SDF-1 levels were established in various mouse tissues by ELISA, immunohistochemistry, and in situ hybridization. To assess the role of SDF-1/CXCR4 in metastasis, bone metastases were established by administering CaP cells into the left cardiac ventricle of nude animals in the presence or absence of neutralizing CXCR4 antibody. The effect of SDF-1 on intraosseous growth of CaP cells was determined using intratibial injections and anti-CXCR4 antibodies and peptides. RESULTS: There was a positive correlation between the levels of SDF-1 and tissues in which metastatic CaP lesions were observed. SDF-1 levels were highest in the pelvis, tibia, femur, liver, and adrenal/kidneys compared with the lungs, tongue, and eye, suggesting a selective effect. SDF-1 staining was generally low or undetectable in the center of the marrow and in the diaphysis. SDF-1 mRNA was localized to the metaphysis of the long bones nearest to the growth plate where intense expression was observed near the endosteal surfaces covered by osteoblastic and lining cells. Antibody to CXCR4 significantly reduced the total metastatic load compared with IgG control-treated animals. Direct intratibial injection of tumor cells followed by neutralizing CXCR4 antibody or a specific peptide that blocks CXCR4 also decreased the size of the tumors compared with controls. CONCLUSIONS: These data provide critical support for a role of SDF-1/CXCR4 in skeletal metastasis. Importantly, these data show that SDF-1/CXCR4 participate in localizing tumors to the bone marrow for prostate cancer.

Expression of CXCR4 and CXCL12 (SDF-1) in human prostate cancers (PCa) in vivo.

Human prostate cancers (PCa) express great variability in their ability to metastasize to bone. The identification of molecules associated with aggressive phenotypes will help to define PCa subsets and will ultimately lead to better treatment strategies. The chemokine stromal-derived factor-1 (SDF-1 or CXCL12) and its receptor CXCR4 are now known to modulate the migration and survival of an increasing array of normal and malignant cell types including breast, pancreatic cancers, glioblastomas, and others. The present investigation extends our previous investigations by determining the expression of CXCR4 and CXCL12 in humans using high-density tissue microarrays constructed from clinical samples obtained from a cohort of over 600 patients. These data demonstrate that CXCR4 protein expression is significantly elevated in localized and metastastic cancers. At the RNA level, human PCa tumors also express CXCR4 and message, but overall, they were not significantly different suggesting post-transcriptional regulation of the receptor plays a major role in regulating protein expression. Similar observations were made for CXCL12 message, but in this case more CXCL12 message was expressed by metastastic lesions as compared to normal tissues. PCa cell lines also express CXCL12 mRNA, and regulate mRNA expression in response to CXCL12 and secrete biologically active protein. Furthermore, neutralizing antibody to CXCL12 decreased the proliferation of bone homing LNCaP C4-2B and PC3 metastastic tumor cells. These investigations provide important new information pertaining to the molecular basis of how tumors may 'home' to bone, and the mechanisms that may account for their growth in selected end organs.