The efficiency of caffeic acid on oxidative stress and angiogenesis in Ehrlich ascites tumor

Abstract

Napredovanje razvoja tumorskih stanica uključuje preživljavanje, širenje, invaziju, angiogenezu i metastaziranje. Reaktivne vrste kisika (ROS) su povezane s brojnim staničnim funkcijama, kao što su stanična proliferacija, diferencijacija, apoptoza i angiogeneza. Prema tome, inhibicija ROS, početnog koraka rasta tumora i angiogeneze, je obećavajući pristup za kemoprevenciju raka i terapiju. Kafeinska kiselina (CA) je biološki aktivna sastavnica propolisa koja pokazuje antioksidativna, protuupalna, antiproliferativna, citostatska, antiangiogena i antineoplastična svojstva. U ovom radu istraživali smo učinak kafeinske kiseline na rast tumora, tumorsku angiogenezu, funkcionalnu sposobnost makrofaga i makrofagnu polarizaciju kao oksidacijski stres u miševa. EAT stanice (2,5 x 106) su injicirane intraperitonealno (ip) u Swiss albino miševe. Nakon inokulacije tumora, miševi su injicirani ip CA u dozi od 40 i 80 mg kg tjelesne težine kroz 10 dana ili u fazi eksponencijalnog rasta od 5 dana nakon injekcije stanica tumora (na dan 5, 7, 9). Na dan 11, analizirali smo ukupni broj stanica ascitesa u peritonealnoj šupljini, volumen ascitesa, diferencijalnu analizu stanica prisutnih u peritonealnoj šupljini, funkcionalna aktivnost makrofaga, antiangiogenične i antioksidativne parametre. CA je inhibirala rast stanica EAT i nastanak ascitesa u peritonealnoj šupljini miševa nositelja EAT. Nadalje, rezultati smanjenja peritonealne angiogeneze i mikrožilne gustoće pokazuju anti-angiogeni potencijal CA in vivo. CA smanjuje razinu NO stanicama EAT, dok razina NO je povećana u peritonealnim makrofagima. Sve u svemu, možemo zaključiti da CA može aktivirati makrofage i povećati njihov citotoksični učinak kroz povećamu proizvodnje NO te spriječiti rast tumora i angiogenezu. Nadalje, CA selektivno povećava nastanak ROS-a u stanicama tumora tijekom 10 dana obrade i mi pretpostavljamo da unutarstanična proizvodnja ROS-a može biti kritičan čimbenik u indukciji apoptoze i CA-selektivnog ubijanja stanica tumora, a čini se da inhibicija angiogeneze i rasta stanica EAT tumora u uznapredovalom stadiju, kada stanice ulaze u eksponencijalnu fazu rasta temelji se na antioksidativnom kapacitetu CA.Progression of tumor cell development involves survival, proliferation, invasion, angiogenesis, and metastasis. Reactive oxygen species (ROS) are associated with multiple cellular functions such as cell proliferation, differentiation, apoptosis and angiogenesis. Therefore, inhibition of the ROS, the initial step of tumor growth and angiogenesis, is a promising strategy for cancer chemoprevention and therapy. Caffeic acid (CA), an active component of propolis extract which exhibits antioxidant, antiinflammatory, antiproliferative, cytostatic, anti-angiogenic and most improtantly, antineoplastic properties. In the present study we investigated the effect of of caffeic acid on tumor growth, tumor angiogenesis, functional ability of macrophages and macrophage polarization as well as oxidative stress in mice. EAT cells (2. 5 x 106) were implanted intraperitoneally (ip) in Swiss albino mice. After tumor inoculation, mice were injected ip with CA at dose of 40 and 80 mg/kg bw during 10 days or in exponential growth phase from the 5 days after tumor cell injection (on day 5, 7, 9). On day 11, ascites volume, the total number of cells, differential count of the cells present in the peritoneal cavity, functional activity of macrophages, anti-angiogenic and antioxidant parameters were determined. The growth of EAT cells and formation of ascites in the peritoneum of EAT-bearing mice was inhibited by CA. Further, results on decrease in the peritoneal angiogenesis and microvessel density show the anti-angiogenic potential of CA in vivo. CA decreased NO level in tumor cells whereas NO level was increased in peritoneal macrophages. Taken together, we conclude that CA may increase the cytotoxic actions of macrophages by increasing NO and inhibit tumor growth and angiogenesis. Moreover, CA selectively caused escalation in the ROS formation in EAT cells during 10 days treated and we speculated that intracellular generation of ROS could be a critical factor in the induction of apoptosis and CA-selective killing of tumor cells while it appears that inhibition of angiogenesis and tumor growth EAT cells in advanced stages when the cells entered into exponential growth period based on the antioxidant capacity CA