Overexpression of PIP5KL1 suppresses the growth of human cervical cancer cells in vitro and in vivo

Regeneration Enhances Metastasis: A Novel Role for Neurovascular Signaling in Promoting Melanoma Brain Metastasis

Neural repair after stroke involves initiation of a cellular proliferative program in the form of angiogenesis, neurogenesis, and molecular growth signals in the surrounding tissue elements. This cellular environment constitutes a niche in which regeneration of new blood vessels and new neurons leads to partial tissue repair after stroke. Cancer metastasis has similar proliferative cellular events in the brain and other organs. Do cancer and CNS tissue repair share similar cellular processes? In this study, we identify a novel role of the regenerative neurovascular niche induced by stroke in promoting brain melanoma metastasis through enhancing cellular interactions with surrounding niche components. Repair-mediated neurovascular signaling induces metastatic cells to express genes crucial to metastasis. Mimicking stroke-like conditions in vitro displays an enhancement of metastatic migration potential and allows for the determination of cell-specific signals produced by the regenerative neurovascular niche. Comparative analysis of both in vitro and in vivo expression profiles reveals a major contribution of endothelial cells in mediating melanoma metastasis. These results point to a previously undiscovered role of the regenerative neurovascular niche in shaping the tumor microenvironment and brain metastatic landscape.

Postnatal developmental dynamics of cell type specification genes in Brn3a/Pou4f1 Retinal Ganglion Cells

BACKGROUND

About 20-30 distinct Retinal Ganglion Cell (RGC) types transmit visual information from the retina to the brain. The developmental mechanisms by which RGCs are specified are still largely unknown. Brn3a is a member of the Brn3/Pou4f transcription factor family, which contains key regulators of RGC postmitotic specification. In particular, Brn3a ablation results in the loss of RGCs with small, thick and dense dendritic arbors ('midget-like' RGCs), and morphological changes in other RGC subpopulations. To identify downstream molecular mechanisms underlying Brn3a effects on RGC numbers and morphology, our group recently performed a RNA deep sequencing screen for Brn3a transcriptional targets in mouse RGCs and identified 180 candidate transcripts.

METHODS

We now focus on a subset of 28 candidate genes encoding potential cell type determinant proteins. We validate and further define their retinal expression profile at five postnatal developmental time points between birth and adult stage, using in situ hybridization (ISH), RT-PCR and fluorescent immunodetection (IIF).

RESULTS

We find that a majority of candidate genes are enriched in the ganglion cell layer during early stages of postnatal development, but dynamically change their expression profile. We also document transcript-specific expression differences for two example candidates, using RT-PCR and ISH. Brn3a dependency could be confirmed by ISH and IIF only for a fraction of our candidates.

CONCLUSIONS

Amongst our candidate Brn3a target genes, a majority demonstrated ganglion cell layer specificity, however only around two thirds showed Brn3a dependency. Some were previously implicated in RGC type specification, while others have known physiological functions in RGCs. Only three genes were found to be consistently regulated by Brn3a throughout postnatal retina development - Mapk10, Tusc5 and Cdh4.

Serum- and glucocorticoid-regulated protein kinase 3 overexpression promotes tumor development and aggression in breast cancer cells

Serum- and glucocorticoid-regulated protein kinase 3 (SGK3) is critical for tumor survival, proliferation and invasion. In the present study we evaluated SGK3 expression in breast tissues and investigated alterations in SGK3 levels in tumor multiplication, progression and apoptosis. Tissue microarray analyses were performed to examine SGK3 expression in breast cancer samples, as well as in adjacent noncancerous and normal tissues. The pEGFP-N1-SGK3 plasmid was transfected into MDA-MB-231 cells to generate SGK3-overexpressing cells. Cell growth assays, colony formation assays, cell cycle analyses, horizontal and vertical migration tests, reverse transcription-polymerase chain reaction and western blot assays were employed to investigate the biological behavior of SGK3-overexpressing cells. SGK3 levels were significantly higher in breast cancer samples compared with adjacent noncancerous and normal tissues. Cell growth curves revealed increased proliferation and decreased apoptosis in SGK3-overexpressing cells. SGK3-overexpressing cells also demonstrated enhanced invasion and migration abilities. SGK3-overexpressing cells had high levels of an apoptosis-related gene (bcl-xl) and invasion-related genes (mmp2 and mmp9), and decreased levels of an anti-apoptosis gene (bad). Phosphorylation of GSK-3β, which is downstream in the phosphoinositide 3-kinase signaling pathway, was activated by SGK3 overexpression. β-catenin phosphorylation did not differ between the SGK3-overexpressing and non-SGK3-overexpressing cells. SGK3 overexpression induces GSK-3β phosphorylation, enhancing apoptosis- and invasion-related genes and proteins and thereby leading to tumor development and aggression in breast cancer cells.