1. Introduction
Angiogenesis is the process
through which new capillaries are sprouted from pre-existing ones
(Eilken et al., 2010). And the components of the vascular wall are
basement membrane, pericytes, vascular smooth muscle cells and
endothelial cells (Carmeliet et al., 2011). The concept of
antiangiogenic therapy, inhibition of angiogenesis could inhibit tumor
growth, started after an observation by Folkman discovering new vessel
production during tumors growth (Folkman, 1971). It is now relatively
cleared that angiogenesis plays an important role in tumor metastasis
and growth (Vasudev et al., 2014; Bielenberg et al., 2015).
The angiogenic system is required
for tumor tissue to grow and develop, and angiogenesis is a complex
process involving an interaction between soluble factors, extracellular
matrix (ECM) components and endothelial cells(ECs) (Patan, 2000). The
early stage of angiogenesis occurs
dynamic functions of ECs including
proliferation, migration and maturation (Griffioen et al., 2000). The
significant event in tumor angiogenesis is
endothelial cell migration, which
relys on the assembly of protease-protein complexes in front of
migrating cells to degrade the basement membrane and invade the matrix
of adjacent tissues (Ausprunk et al., 1977; Liekens et al., 2001).
Notably, the chronic imbalance of proangiogenic and antiangiogenic
factors leads to abnormal angiogenesis in tumor
tissues (Goel
et al., 2011;
Carmeliet et al., 2011).
Aspirin (acetylsalicylic acid, ASA) is an old medicine that was
originally extracted from willow bark and is widely used in the
prevention and treatment of cardiovascular and cerebrovascular diseases
(Desborough et al., 2017). It is absorbed in the gastrointestinal tract
after oral administration of aspirin in man, and then converted into
salicylic acid (SA) which is further metabolized to salicyhxic acid,
gentisic acid, gentisuric acid
(2,5-DHBA), salicyl acyl
glucuronide, and salicyl phenolic
glucuronide
(Rumble et al., 1981). During the
circulation process, the biological activity of salicylic acid is
impaired due to the large amount of salicylic acid (50-80%) bound to
albumin, which is because the free salicylic acid has biological
activity (Hua et al., 2019).
Increasing evidence have shown that long-term regular aspirin use can
significantly reduce the risk of overall cancer
(Cao et al., 2016). These effects
may be related to the antiangiogenic ability of aspirin (Pearce et al.,
2003; Yoshida et al., 2003; Tsujii et al., 1998). Here, we update recent
researches on the antiangiogenic effects of aspirin in cancer prevention
and treatment, and analyze the
several molecular mechanisms of the antiangiogenesis effects for cancer
by aspirin.