Endocrine Abstracts

Introduction: The HECa10 line was derived from the specialized endothelial cells typically occurring in lymphoid tissues and belonging to high endothelial vessels (HEVs). Recent studies have shown that HEVs are also present within the tumor microenvironment, what unlike to other blood vessels, can be associated with favorable prognosis of cancer patients. Estradiol (E2) and its metabolite 2-methoxyestradiol (2ME2) are known as the important modulators of cardiovascular system changing growth processes of different endothelial lines. However, there is no data concerning their effect on HEV lines. Thus, we studied the direct effects of E2 and 2ME2 on the growth of HECa10 line in vitro.

Methods: The growth of HECa10 line was assessed by two methods: the colorimetric Mosmann’s method reflecting total metabolic activity of cultured cells and the fluorescence CyQUANT^® method reflecting number of cultured cells. The effect of various concentrations of E2 (mainly physiological) and 2ME2 was examined in 12, 24, 36 and 72 h cultures.

Results: Estradiol in 72 h culture stimulated the growth of HECa10 line with moderate potency increasing number of cultured cells at four concentrations (10⁻⁷, 3×10⁻⁸, 10⁻⁸, 10⁻⁹ M) and its metabolic activity only at two concentrations (3×10⁻⁸, 4×10⁻⁹ M). However, at another two concentrations (10⁻⁷, 4×10⁻⁹ M) it inhibited metabolic activity of this line. The stimulatory effect of E2 at concentration 10⁻⁸ M was noted since 36 h cultured.

In turn, 2ME2 inhibited the growth of HECa10 line in 72 h culture with great potency at two the highest pharmacological concentrations (10⁻⁴, 10⁻⁶ M) and with moderate strength at one the lowest tested concentration (10⁻¹² M) (physiological concentration) (assessed by two methods). Its inhibitory effect was observed also in 24 and 36 h cultures.

Conclusions: Estradiol and its metabolite 2-methoxyestradiol modulate the growth of HECa10 line acting with different strength and generally in the opposite way.