Matrix-Dependent Regulation of AKT in Hepsin-Overexpressing PC3 Prostate Cancer Cells

Abstract

The serine-protease hepsin is one of the most prominently overexpressed genes in human prostate carcinoma. Forced expression of the enzyme in mice prostates is associated with matrix degradation, invasive growth, and prostate cancer progression. Conversely, hepsin overexpression in metastatic prostate cancer cell lines was reported to induce cell cycle arrest and reduction of invasive growth in vitro. We used a system for doxycycline (dox)-inducible target gene expression in metastasis-derived PC3 cells to analyze the effects of hepsin in a quantitative manner. Loss of viability and adhesion correlated with hepsin expression levels during anchorage-dependent but not anchorage-independent growth. Full expression of hepsin led to cell death and detachment and was specifically associated with reduced phosphorylation of AKT at Ser(473), which was restored by growth on matrix derived from RWPE1 normal prostatic epithelial cells. In the chorioallantoic membrane xenograft model, hepsin overexpression in PC3 cells reduced the viability of tumors but did not suppress invasive growth. The data presented here provide evidence that elevated levels of hepsin interfere with cell adhesion and viability in the background of prostate cancer as well as other tissue types, the details of which depend on the microenvironment provided. Our findings suggest that overexpression of the enzyme in prostate carcinogenesis must be spatially and temporally restricted for the efficient development of tumors and metastases.

Active Targeting of Mesoporous Silica Drug Carriers Enhances γ-Secretase Inhibitor Efficacy in An In Vivo Model for Breast Cancer

“…For folic acid (FA) conjugation, 25 mg PEI-functionalized particles were suspended in 4-morpholineethanesulfonic acid buffer (pH 4.8). n Chicken CAM assay The CAM assay was performed as described previously [34]. The suspension was agitated for 4 h, separated by centrifugation, washed with deionized water and ethanol, dried in a vacuum and stored at 277 K. The amount of conjugated FA was determined by dissolving a known amount of particles (1 mg/ml) in 1 M NaOH overnight and measuring the amount of FA by a UV spectrophoto meter (NanoDrop 2000c ® , Thermo Scientific, DE, USA) reading at l = 280 nm, from which a similarly dissolved FITC sample was subtracted in order to remove the background contribution of FITC.…”

“…The CAM model has been employed to evaluate drug-delivery systems [28], the efficiency of anticancer drugs [30][31][32], as well as the consequences of genetic modulation on growth and apoptotic rate of tumor xenografts [33,34]. It does not raise ethical/legal questions, nor does it violate animal protection laws.…”

ERG Induces Epigenetic Activation of Tudor Domain-Containing Protein 1 (TDRD1) in ERG Rearrangement-Positive Prostate Cancer

“…Stably transfected LNCaP clones were generated as previously described [32]. Transgene expression was induced with 50 ng/ml doxycycline (Sigma).…”

Doxycycline directly targets PAR1 to suppress tumor progression

“…In a previous study, doxycycline was found to inhibit angiogenesis in chick chorioallantoic membrane (CAM) samples by repressing the activity of matrix metalloproteinases (MMPs) [26, 27]. Until now, doxycycline was still considered an anti-angiogenesis drug that functions through the inhibition of MMPs.…”