[The mechanisms of angiogenesis. Medical and therapeutic applications]

The Angiogenic Balance and Its Implications in Cancer and Cardiovascular Diseases: An Overview

Angiogenesis is the process of developing new blood vessels from pre-existing ones. This review summarizes the main features of physiological and pathological angiogenesis and those of angiogenesis activation and inhibition. In healthy adults, angiogenesis is absent apart from its involvement in female reproductive functions and tissue regeneration. Angiogenesis is a complex process regulated by the action of specific activators and inhibitors. In certain diseases, modulating the angiogenic balance can be a therapeutic route, either by inhibiting angiogenesis (for example in the case of tumor angiogenesis), or by trying to activate the process of new blood vessels formation, which is the goal in case of cardiac or peripheral ischemia.

To Determine Pivotal Genes Driven by Methylated DNA in Obstructive Sleep Apnea Hypopnea Syndrome

Obstructive sleep apnea syndrome (OSAHS) is a widespread respiratory dysfunction that has attracted more and more attention in recent years. Recently, a large number of studies have shown that abnormal DNA methylation epigenetically silences genes necessary for the pathogenesis of human diseases. However, the exact mechanism of abnormal DNA methylation in OSAHS is still elusive. In this study, we downloaded the OSAHS data from the GEO database. Our data for the first time revealed 520 hypermethylated genes and 889 hypomethylated genes in OSAHS. Bioinformatics analysis revealed that these abnormal methylated genes exhibited an association with the regulation of angiogenesis, apoptosis, Wnt, and ERBB2 signaling pathways. PPI network analysis displayed the interactions among these genes and validated several hub genes, such as GPSM2, CCR8, TAS2R20, TAS2R4, and TAS2R5, which were related to regulating liganded Gi-activating GPCR and the transition of mitotic metaphase/anaphase. In conclusion, our study offers a new hint of understanding the molecular mechanisms in OSAHS progression and will provide OSAHS with newly generated innovative biomarkers.

The Role of YAP and TAZ in Angiogenesis and Vascular Mimicry

Angiogenesis, the formation of new blood vessels from pre-existing vasculature, is a physiological process that begins in utero and continues throughout life in both good health and disease. Understanding the underlying mechanism in angiogenesis could uncover a new therapeutic approach in pathological angiogenesis. Since its discovery, the Hippo signaling pathway has emerged as a key player in controlling organ size and tissue homeostasis. Recently, new studies have discovered that Hippo and two of its main effectors, Yes-associated protein (YAP) and its paralog transcription activator with PDZ binding motif (TAZ), play critical roles during angiogenesis. In this review, we summarize the mechanisms by which YAP/TAZ regulate endothelial cell shape, behavior, and function in angiogenesis. We further discuss how YAP/TAZ function as part of developmental and pathological angiogenesis. Finally, we review the role of YAP/TAZ in tumor vascular mimicry and propose directions for future work.

Silymarin inhibits melanoma cell growth both in vitro and in vivo by targeting cell cycle regulators, angiogenic biomarkers and induction of apoptosis

Cutaneous malignant melanoma is the leading cause of death from skin diseases and is often associated with activating mutations of the proto-oncogene BRAF. To develop more effective strategies for the prevention or treatment of melanoma, we have examined the inhibitory effects of silymarin, a flavanoid from Silybum marianum, on melanoma cells. Using A375 (BRAF-mutated) and Hs294t (non BRAF-mutated but highly metastatic) human melanoma cell lines, we found that in vitro treatment with silymarin resulted in a dose-dependent: (i) reduction in cell viability; (ii) enhancement of either Go/G1 (A375) or G2-M (Hs294t) phase cell cycle arrest with corresponding alterations in cyclins and cyclin-dependent kinases; and (iii) induction of apoptosis. The silymarin-induced apoptosis of human melanoma cells was associated with a reduction in the levels of anti-apoptotic proteins (Bcl-2 and Bcl-xl), an increase in the levels of pro-apoptotic protein (Bax), and activation of caspases. Further, oral administration of silymarin (500 mg/kg body weight/2× a week) significantly inhibited (60%, P < 0.01) the growth of BRAF-mutated A375 melanoma tumor xenografts, and this was associated with: (i) inhibition of cell proliferation; (ii) induction of apoptosis of tumor cells; (iii) alterations in cell cycle regulatory proteins; and (iv) reduced expression of tumor angiogenic biomarkers in tumor xenograft tissues. These results indicate that silymarin may have a chemotherapeutic effect on human melanoma cell growth and warrant its further evaluation.

Efeitos da prostaglandina E1 (PGE1) na gênese de capilares sanguíneos em músculo esquelético isquêmico de ratos: estudo histológico

CONTEXTO: A angiogênese terapêutica é uma modalidade de tratamento para pacientes com insuficiência arterial crônica que não têm indicação para revascularização direta ou angioplastia e que não tiveram uma resposta satisfatória ao tratamento clínico. Entre as drogas utilizadas para essa finalidade está a prostaglandina E1 (PGE1). OBJETIVO: Estudar os aspectos morfológicos na gênese de capilares sanguíneos em músculo esquelético do membro caudal de ratos submetidos à isquemia sob a ação da PGE1, administrada por via intramuscular (IM) ou endovenosa (EV). MÉTODOS: Foram utilizados 48 ratos, linhagem Wistar-UEM, distribuídos aleatoriamente em três grupos de 16, redistribuídos igualmente em dois subgrupos, observados no 7º e 14º dias, sendo um grupo controle onde apenas foi provocada a isquemia no membro, outro com a isquemia e a injeção da PGE1 via IM e outro com a isquemia e a injeção da PGE1 EV. Para análise dos resultados, foram realizadas a coloração com hematoxilina e eosina (HE) e coloração imuno-histoquímica. RESULTADOS: Constatou-se um aumento estatisticamente significativo no número de capilares nos subgrupos com o uso da PGE1 IM e EV, através da contagem nos cortes corados com HE. A imunomarcação não foi eficiente para a quantificação dos capilares. CONCLUSÕES: A PGE1, administrada por via IM ou EV, promoveu, após 14 dias de observação, um aumento no número de capilares no músculo esquelético de ratos submetido à isquemia, identificáveis histologicamente com a coloração em HE. A imunocoloração não permitiu estabelecer uma correlação com o aumento de vasos encontrados na coloração com HE.