Effects of thalidomide, cytochrome P-450 and TNF-alpha on angiogenesis in a three-dimensional collagen gel-culture

Lenalidomide and pomalidomide inhibit growth of prostate stromal cells and human prostate smooth muscle contraction

AIMS

Medical treatment for lower urinary tract symptoms secondary to benign prostatic hyperplasia is characterized by an unfavorable balance between limited efficacy and pronounced side effects. We recently reported, that thalidomide reduces prostate smooth muscle contraction and inhibits cell growth. Like thalidomide, its analogs lenalidomide and pomalidomide are also in clinical use. Therefore, we investigated the effects of lenalidomide and pomalidomide on human prostate smooth muscle contraction, cytoskeletal organization, and growth-related functions in stromal cells.

MATERIALS AND METHODS

Proliferation was assessed by EdU assay and colony formation, cytoskeletal organization by phalloidin staining, cell viability by CCK8, and apoptosis and cell death by flow cytometry in cultured prostate stromal cells (WPMY-1). Contractions of human prostate tissues from radical prostatectomy were induced by methoxamine, noradrenaline, phenylephrine, endothelin-1, U46619, or electric field stimulation (EFS) in an organ bath.

KEY FINDINGS

Proliferation of WPMY-1 cells was significantly reduced by lenalidomide (5-200 μM) and pomalidomide (2.5-5 μM). In parallel, organization of actin filaments collapsed after treatment with lenalidomide and pomalidomide. Lenalidomide and pomalidomide inhibited both adrenergic contractions and non-adrenergic contractions as well as neurogenic contractions induced by EFS. Neither reduction in viability, nor increase in cell death or apoptosis was observed in WPMY-1 cells.

SIGNIFICANCE

Thalidomide-derivatives impair growth of human prostate stromal cells, without showing a decrease in cell viability and, in parallel, inhibit adrenergic, neurogenic, and non-adrenergic contractions by breakdown of the actin cytoskeleton. Urodynamic effects in vivo appear possible.

Inhibition of human prostate stromal cell growth and smooth muscle contraction by thalidomide: A novel remedy in LUTS?

BACKGROUND

Medical treatment in benign prostatic hyperplasia targets prostate size to prevent disease progression, complications, and surgery, and prostate smooth muscle tone for rapid relief of lower urinary tract symptoms. Combination therapies are still required to target both at once. However, current medications are insufficient, due to an unfavorable balance between side effects and efficacy. The limited efficacy of α₁ -blockers may be due to nonadrenergic mediators like endothelin-1 and thromboxane A₂ (TXA₂ ), which keep up prostate smooth muscle contraction even in the presence of α₁ -blockers. Consequently, future options with higher efficacy need to target α₁ -adrenergic and nonadrenergic contractions as well as stromal cell growth at once. Thalidomide has been approved as an oral medication for various diseases, including the treatment of prostate cancer. Therefore, we investigated the effect of thalidomide on cellular functions of prostate stromal cells and human prostate smooth muscle contraction.

METHODS

Cytoskeletal organization was visualized by phalloidin staining, cell growth was assessed by 5-ethynyl-2'-deoxyuridine assay, cell viability by cell counting kit-8, and apoptosis and cell death by flow cytometry in cultured prostate stromal cells (WPMY-1). Contractions of human prostate tissues from radical prostatectomy were studied in an organ bath, where they were induced by the α₁ -adrenoceptor agonists methoxamine, noradrenaline, phenylephrine, and the nonadrenergic agonists endothelin-1, TXA₂ analog U46619, or electric field stimulation (EFS).

RESULTS

Thalidomide significantly reduced the proliferation of WPMY-1 cells, which was time- and concentration-dependent (10-300 µM). In parallel, organization of actin filaments collapsed after treatment with thalidomide. Thalidomide (30-100 µM) inhibited noradrenaline-, phenylephrine-, and methoxamine-induced contractions, as well as nonadrenergic contractions induced by endothelin-1 and U46619, and neurogenic contractions induced by EFS. No reduction in viability and no increases in apoptosis or in cell death were observed in WPMY-1 cells.

CONCLUSIONS

Thalidomide impairs the growth of human prostate stromal cells, without showing a decrease in cell viability. In parallel, thalidomide inhibits adrenergic, neurogenic, and nonadrenergic contractions. This may be explained by a breakdown of the actin cytoskeleton. In vivo, urodynamic effects of thalidomide appear possible and may even exceed those of α₁ -blockers or combination therapies.

Detection of the Hematopoietic Stem and Progenitor Cell Marker CD133 during Angiogenesis in Three-Dimensional Collagen Gel Culture

We detected the hematopoietic stem and progenitor cell marker CD133 using immunogold labeling during angiogenesis in a three-dimensional collagen gel culture. CD133-positive cells were present in capillary tubes newly formed from aortic explants in vitro. The CD133-positive cell population had the capacity to form capillary tubes. Lovastatin strongly inhibited cell migration from aortic explants and caused the degradation of the capillary tubes. The present study provides insight into the function of CD133 during angiogenesis as well as an explanation for the antiangiogenic effect of statins.

Over-expression of tumor necrosis factor-alpha in bone marrow biopsies from patients with myelodysplastic syndromes: relationship to anemia and prognosis

OBJECTIVES

An excessive intramedullar progenitor cell apoptosis, to which elevated expression of tumor necrosis factor-alpha (TNF-alpha) might contribute, is considered the main cause of inefficient hematopoiesis in myelodysplastic syndromes (MDS). Enhanced bone marrow (BM) angiogenesis is regarded as an essential cofactor in the progression of MDS to acute myelogenous leukemia (AML) and microvessel formation may be induced by TNF-alpha as well. To investigate TNF-alpha signaling and neoangiogenesis as potential molecular pathways for therapeutic intervention in MDS with respect to the various MDS subtypes, we performed a morphological and clinico-pathological study on a large series of paraffin-embedded trephine BM biopsies.

METHODS

TNF-alpha expression and BM vessels were immunohistochemically analyzed on 89 paraffin-embedded BM biopsies from patients with MDS and secondary AML, including 12 control samples. Data were correlated with clinico-pathological and laboratory parameters and analyzed for their prognostic significance considering overall survival.

RESULTS

TNF-alpha was over-expressed in MDS patients, especially in those with refractory anemia and its expression correlated with BM cellularity and with magnitude of anemia as well as with microvessel density (MVD). TNF-alpha over-expression was associated with premature deaths. MVD was increased in MDS and secondary AML and correlated with marrow cellularity and expression of TNF-alpha, but was not of prognostic significance.

CONCLUSIONS

TNF-alpha expression and MVD are elevated in MDS and secondary AML. TNF-alpha expression in BM progenitor cells appears to negatively impact erythropoiesis and overall survival in MDS, and may serve as a potential therapeutic target in patients with hypercellular MDS with marked anemia.

An in vitro model for studying vascular injury after laser microdissection

We have developed an in vitro model for studying vascular injury. After 7-10 days in a three-dimensional collagen gel culture, capillary-like tubes were formed in the collagen gels. We injured these capillary-like tubes with a laser microdissection system or a scrape method with razors and then examined the collagen gel culture by phase contrast and electron microscopy. After laser injury, profuse necrotic cells were observed around the injured capillary-like tubes and within the tubular lumen compared to the razor injury. We then isolated total RNA from these cultures and prepared cDNA for investigations by quantitative real-time reverse transcription polymerase chain reaction (RT-PCR). Quantitative real time RT-PCR revealed the up-regulation of transcription factor early growth response-1 (Egr-1) after both laser and razor injury, accompanied by the up-regulation of fibroblast growth factor-2 (FGF-2), a proangiogenic factor downstream of Egr-1. The effective laser energy is concentrated on the minute focal spot only. These methods provide a useful in vitro model for studying vascular injury.

Anti-angiogenic effects of thalidomide: expression of apoptosis-inducible active-caspase-3 in a three-dimensional collagen gel culture of aorta

The anti-angiogenic properties of thalidomide have led to the use of the agent as a remedy for multiple myeloma. Nevertheless, the anti-angiogenic moiety of thalidomide remains unidentified. In this study we examined the anti-angiogenic effects of thalidomide in an in vitro model using a three-dimensional collagen gel culture. Angiogenesis was significantly inhibited when the culture was treated with thalidomide plus cytochrome P-450 (CYP2B4), and the migrating cells and tubules were positive for active-caspase-3 in an accompanying immunohistochemical investigation. Transmission electron microscopic observation also confirmed that active-caspase-3-positive cells demonstrated apoptotic characteristics. This study is the first to morphologically demonstrate the effect of thalidomide in directly inducing the apoptosis of new tubules and migrating cells on a three-dimensional collagen gel culture of aorta. Taken together with earlier findings, our new results indicate that the thalidomide-induced inhibition of angiogenesis involves apoptosis in addition to the suppression of TNF-alpha and inhibition of cell migration from aorta explants, i.e., the factors important for capillarogenesis.

Angiogenesis and fibroblast growth factors (FGFs) in a three-dimensional collagen gel culture

Small pieces of mouse aorta were cultured in collagen gels, and the formation of capillary-like tubes from the aortic explant was observed under phase-contrast and transmission electron microscopes. Migration of fibroblastic cells from the aortic explant occurred in 2 days. After about 10 days of culture, capillary-like tubes from the aortic explant were formed in the collagen gels. An immunohistochemical study on the collagen gel culture revealed the expression of fibroblast growth factor 2 (FGF-2) near the aortic explant at the active initial stage, with random migration of fibroblastic cells expressing FGF-9. mRNA was isolated from these cultures, and reverse transcription-polymerase chain reaction (RT-PCR) of the cultures revealed the expressions of both FGF-2 and FGF-9. Based on our results, we propose that FGF-9 is also related to angiogenic events.