No abstract

Recently, there have been reports of postnatal vasculogenesis in cases of ischaemia models. The aim of the present study is to provide evidence of postnatal vasculogenesis in breast-cancer -bearing mice. Based on cell surface antigen expression, we isolated endothelial precursor cells from bone marrow, peripheral blood and tumour-infiltrating cells from mice that had received six human breast cancer xenografts. In all three areas (bone marrow, peripheral blood and tumour-infiltrating cells), endothelial precursor cell population was elevated in all transplanted mice. Differentiation and migration activities of endothelial precursor cells were measured by comparing levels of the endothelial precursor cell maturation markers Flk-1, Flt-1, Tie2, VE-cadherin and CD31 among these three areas. The endothelial precursor cell population was 14% or greater in the gated lymphocyte-size fraction of the inflammatory breast cancer xenograft named WIBC-9, which exhibits a hypervascular structure and de novo formation of vascular channels, namely vasculogenic mimicry (Shirakawa et al, 2001). In vitro, bone marrow-derived endothelial precursor cells from four human breast cancer xenografts proliferated and formed multiple clusters of spindle-shaped attaching cells on a vitronectin-coated dish. The attaching cells, which incorporated DiI-labelled acetylated low-density lipoprotein (DiI-acLDL) and were negative for Mac-1. The putative bone marrow derived endothelial precursor cell subset, which was double positive of CD34 and Flk-1, and comparative bone marrow derived CD34 positive with Flk-1 negative subset were cultured. The former subset incorporated DiI-acLDL and were integrated with HUVECs. Furthermore, they demonstrated significantly higher levels of murine vascular endothelial growth factor and interleukin-8 in culture supernatant on time course by enzyme-linked immunosorbent assay. These findings constitute direct evidence that breast cancer induces postnatal vasculogenesis in vivo.

Among the many tissue stem or progenitor cells recently being unveiled, endothelial progenitor cells (EPCs) have attracted particular attention, not only because of their cardinal role in vascular biology and embryology but also because of their potential use in the therapeutic development of a variety of postnatal diseases, including cardiovascular and peripheral vascular disorders and cancer. The aim of this study is to provide some basic and comprehensive information on gene expression of EPCs to characterize the cells in molecular terms. Here, we focus on EPCs derived from CD34-positive mononuclear cells of human umbilical cord blood. The EPCs were purified and expanded in culture and analyzed by a high-density oligonucleotide microarray and real-time RT-PCR analysis. We identified 169 up-regulated and 107 down-regulated genes in the EPCs compared with three differentiated endothelial cells of human umbilical vein endothelial cells (HUVEC), human lung microvascular endothelial cells (LMEC) and human aortic endothelial cells (AoEC). It is expected that the obtained list include key genes which are critical for EPC function and survival and thus potential targets of EPC recognition in vivo and therapeutic modulation of vasculogenesis in cancer as well as other diseases, in which de novo vasculogenesis plays a crucial role. For instance, the list includes Syk and galectin-3, which encode protein tyrosine kinase and beta-galactoside-binding protein, respectively, and are expressed higher in EPCs than the three control endothelial cells. In situ hybridization showed that the genes were expressed in isolated cells in the fetal liver at E11.5 and E14.5 of mouse development.

BackgroundStudies of prostate‐specific antigen (PSA)‐based population screening have been conducted in western countries, but there is little data in Asian populations. The objective of this study was to determine the efficacy of PSA screening in Asian men using real‐world data over a period of 15 years after introducing population screening in Yokosuka City, Japan.MethodsWe investigated patients with pathologically diagnosed prostate cancer at four hospitals and two clinics across the Yokosuka area (Miura peninsula) between April 2001 and March 2015. Patients were divided into two groups; the S group consisted of those diagnosed by PSA‐based population screening in Yokosuka City and the NS group consisted of those diagnosed by methods other than screening. Cancer‐specific survival (CSS) and overall survival (OS) rates were calculated using the Kaplan‐Meier method with the log‐rank test to compare survival between the two groups. Clinical and pathological factors for cancer‐specific mortality were assessed with Cox regression analyses to calculate the hazard ratio (HR) and 95% confidence interval (CI).ResultsA total of 3094 patients had been diagnosed with prostate cancer over the 15‐year period. The median follow‐up period was 77 months. The S group and the NS group consisted of 977 and 2117 patients, respectively. Patients in the S group were younger (age: 71 years vs 73 years, P < .001) and had a lower Charlson comorbidity index (CCI) with favorable oncological factors, such as lower initial PSA, Gleason score (GS), and risk category. Kaplan‐Meier curves for OS and CSS revealed significant differences between the two groups (OS: P < .001, CSS: P < .001). Analysis with Cox proportional hazards model indicated the NS group (HR: 1.584, 95% CI, 1.065‐2.356, P = .023), a CCI > 4 (HR: 1.552, 95% CI, 1.136‐2.120, P = .006), a GS ≥ 8 (HR: 4.869, 95% CI, 2.631‐9.001, P < .001), and nonlocalized cancer (locally advanced; HR: 2.632, 95% CI, 1.676‐4.133, P < .001, advanced; HR: 9.468, 95% CI, 6.279‐14.278, P < .001) as independent risk factors for cancer‐specific mortality.ConclusionsPSA‐based population screening of prostate cancer might be useful in the Japanese population.

Androgen ablation has been the standard treatment for metastasized prostate cancer. In most cases, however, prostate cancer cells eventually lose androgen dependency and become refractory to the conventional endocrine therapy. Androgen-independent prostate cancer is characterized by a heterogeneous loss of androgen receptor (AR) expression among tumor cells. Prostate-specific promoters such as prostate-specific antigen and rat probasin (rPB) promoters have been examined in the development of gene therapy targeted to prostate cancer. However, those promoters require binding of the androgen-AR complex to the androgen-response element and are active only in the androgen-dependent prostate cancer cell lines and not in the androgen-independent cell lines. To target transgene expression in androgen-independent prostate cancer, we designed a prostate-specific promoter that is activated by the retinoids-retinoid receptor complex instead of the androgen-AR complex. The modified rPB promoters expressed transgenes in response to retinoid in both androgen-dependent and androgen-independent prostate cancer cells and not in other cancer cell lines or in human normal cells, in vitro and in vivo. Furthermore, the combination of retinoid treatment and adenovirus-mediated gene transfer of the modified rPB-driven HSV-tk gene resulted in a significant growth suppression of the androgen-independent prostate cancer cells in the presence of the prodrug ganciclovir. This study suggests that tailoring of the hormone-responsive elements may offer a new therapeutic opportunity against the hormone-refractory stage of prostate cancer.