Epidermal growth factor enhances invasive activity of BeWo choriocarcinoma cells by inducing alpha2 integrin expression

Computational model of wound healing: EGF secreted by fibroblasts promotes delayed re-epithelialization of epithelial keratinocytes

It is widely agreed that keratinocyte migration plays a crucial role in wound re-epithelialization. Defects in this function contribute to wound reoccurrence causing significant clinical problems. Several in vitro studies have shown that the speed of migrating keratinocytes can be regulated by epidermal growth factor (EGF) which affects keratinocyte's integrin expression. The relationship between integrin expression (through cell-matrix adhesion) stimulated by EGF and keratinocyte migration speed is not linear since increased adhesion, due to increased integrin expression, has been experimentally shown to slow down cell migration due to the biphasic dependence of cell speed on adhesion. In our previous work we showed that keratinocytes that were co-cultured with EGF-enhanced fibroblasts formed an asymmetric migration pattern, where, the cumulative distances of keratinocytes migrating toward fibroblasts were smaller than those migrating away from fibroblasts. This asymmetric pattern is thought to be provoked by high EGF concentration secreted by fibroblasts. The EGF stimulates the expression of integrin receptors on the surface of keratinocytes migrating toward fibroblasts via paracrine signaling. In this paper, we present a computational model of keratinocyte migration that is controlled by EGF secreted by fibroblasts using the Cellular Potts Model (CPM). Our computational simulation results confirm the asymmetric pattern observed in experiments. These results provide a deeper insight into our understanding of the complexity of keratinocyte migration in the presence of growth factor gradients and may explain re-epithelialization failure in impaired wound healing.

Placental basement membrane proteins are required for effective cytotrophoblast invasion in a three-dimensional bioprinted placenta model

Fetal cytotrophoblast invasion of maternal decidual vasculature is necessary to normal pregnancy. In preeclampsia, there is shallow invasion and abnormal remodeling of the uterine vasculature that lead to significant maternal and perinatal morbidity and mortality. The placental basement membrane (BM) proteins (e.g., laminin and collagen) has been implicated in the development of placenta while the level of laminin is significantly lower in preeclampsia. However, there are very limited studies, if any, on the effect of extracellular matrix (ECM) microenvironment on the invasion of cytotrophoblast. In this study, we hypothesized that placental BM proteins are required for effective cytotrophoblast invasion. Using proteomics, we found that more than 80% of ECM proteins in placental basal plate (pECM) were BM proteins. In addition to upregulating expressions of MMP2 (1.5-fold) and MMP9 (6.3-fold), pECM significantly increased the motility rates of cytotrophoblasts by 13-fold (from 5.60 ± 0.95 to 75.5 ± 21.8 µm/day) to achieve an effective invasion rate that was comparable to in vivo results. Treatments with PI3K inhibitors completely removed the pECM-enhanced invasive phenotypes and genotypes of cytotrophoblasts, suggesting its dominant role in cytotrophoblast-ECM interactions. Our results described, for the first time, the substantial effects of the ECM microenvironment on regulating cytotrophoblast invasion, an area that is less investigated but appear to be critical in the pathogenesis of preeclampsia. Moreover, the approach presented in this work that fabricates organ models with organ-specific ECM can be an attractive option to screen and develop novel therapeutics and biomarkers not only in preeclampsia but also other diseases such as cancer metastasis. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1476-1487, 2018.

Sulforaphane inhibits proliferation and invasive activity of everolimus-resistant kidney cancer cells in vitro

Although the mechanistic target of rapamycin (mTOR) inhibitor, everolimus, has improved the outcome of patients with renal cell carcinoma (RCC), improvement is temporary due to the development of drug resistance. Since many patients encountering resistance turn to alternative/complementary treatment options, an investigation was initiated to evaluate whether the natural compound, sulforaphane (SFN), influences growth and invasive activity of everolimus-resistant (RCCres) compared to everolimus-sensitive (RCCpar) RCC cell lines in vitro. RCC cells were exposed to different concentrations of SFN and cell growth, cell proliferation, apoptosis, cell cycle, cell cycle regulating proteins, the mTOR-akt signaling axis, adhesion to human vascular endothelium and immobilized collagen, chemotactic activity, and influence on surface integrin receptor expression were investigated. SFN caused a significant reduction in both RCCres and RCCpar cell growth and proliferation, which correlated with an elevation in G2/M- and S-phase cells. SFN induced a marked decrease in the cell cycle activating proteins cdk1 and cyclin B and siRNA knock-down of cdk1 and cyclin B resulted in significantly diminished RCC cell growth. SFN also modulated adhesion and chemotaxis, which was associated with reduced expression of the integrin subtypes α5, α6, and β4. Distinct differences were seen in RCCres adhesion and chemotaxis (diminished by SFN) and RCCpar adhesion (enhanced by SFN) and chemotaxis (not influenced by SFN). Functional blocking of integrin subtypes demonstrated divergent action on RCC binding and invasion, depending on RCC cell sensitivity to everolimus. Therefore, SFN administration could hold potential for treating RCC patients with established resistance towards everolimus.

Quantifying the biomechanics of conception: L-selectin-mediated blastocyst implantation mechanics with engineered "trophospheres"

An estimated 12% of women in the United States suffer from some form of infertility. In vitro fertilization (IVF) is the most common treatment for infertility encompassing over 99% of all assisted reproductive technologies. However, IVF has a low success rate. Live birth rates using IVF can range from 40% in women younger than 35 years to 4% in women older than 42 years. Costs for a successful IVF outcome can be upward of $61,000. The low success rate of IVF has been attributed to the inability of the blastocyst to implant to the uterus. Blastocyst implantation is initiated by L-selectin expressing cells, trophoblasts, binding to L-selectin ligands, primarily sialyl Lewis X (sLeX), on the uterine surface endometrium. Legal and ethical considerations have limited the research on human subjects and tissues, whereas animal models are costly or do not properly mimic human implantation biochemistry. In this work, we describe a cellular model system for quantifying L-selectin adhesion mechanics. L-selectin expression was confirmed in Jeg-3, JAR, and BeWo cell lines, with only Jeg-3 cells exhibiting surface expression. Jeg-3 cells were cultured into three-dimensional spheres, termed "trophospheres," as a mimic to human blastocysts. Detachment assays using a custom-built parallel plate flow chamber show that trophospheres detach from sLeX functionalized slides with 2.75 × 10(-3) dyn of force and 7.5 × 10(-5) dyn-cm of torque. This work marks the first time a three-dimensional cell model has been utilized for quantifying L-selectin binding mechanics related to blastocyst implantation.

Human trophoblast function during the implantation process

The implantation process involves complex and synchronized molecular and cellular events between the uterus and the implanting embryo. These events are regulated by paracrine and autocrine factors. Trophoblast invasion and migration through the uterine wall is mediated by molecular and cellular interactions, controlled by the trophoblast and the maternal microenvironment. This review is focused on the molecular constituents of the human trophoblast, their actions and interactions, including interrelations with the uterine endometrium.