奥曲肽联合汉防己甲素对人胃癌细胞增殖的影响

Inhibitory effects of tetrandrine combined with octreotide on proliferation of gastric cancer cell lines cultured in vitro

目的:观察奥曲肽、汉防己甲素单独及联合应用对体外培养人胃癌细胞株增殖的影响,并初步探讨其可能的作用机制．方法:以MTT比色法观察奥曲肽(善宁)、汉防己甲素 (Tet)单独及联合应用对体外培养人胃癌细胞株SGC 7901和MKN 45增殖的影响,并用Fura-2／AM荧光标记法测定了其对胃癌细胞内游Ca2+浓度的影响．结果:2．4×10-5 mol／L、2．4×10-6 mol／L高浓度奥曲肽、10-160 μmol／L浓度范围的Tet对体外培养人胃癌细胞株SGC 7901和MKN 45均有显著的抑制作用,其增殖抑制率(IR)分别为,对SGC 7901:40．76％、 23．2％和30．5-70．0％;对MKN 45:24．9％、21．7％和 20．4-79．01％(P<0．05或P<0．01);奥曲肽2．4×10-6、2．4 ×10-9、2．4×10-12 mol／L分别与Tet 10 μmol／L联合应用,可将其对SGC7901和MKN 45的IR分别由32．8％和 27．0％提高至50．5％和60．3％、55．0％和47．7％、67．8％和63．0％(vs Tet组P<0．05或P<0．01)．10 μmol／L Tet作用于SGC 7901和MKN 45,其细胞内游离Ca2+浓度较对照组显著降低(394．2±18．4 nmol／L vs 505．0±15．8 nmol／L, 412．1±20．8 nmol／L vs 512．0±16．0 nmol／L,P<0．01);2．4 ×10-6 mol／L奥曲肽亦可显著降低胃癌细胞内的钙离子浓度(SGC 7901 450．8±20．1 nmol／L,P<0．01;MKN45 413．1±10．4 nmol／L,P<0．01)．但奥曲肽联合Tet并不能进一步降低胃癌细胞内钙离子浓度．结论:Tet对体外培养人胃癌细胞有剂量依赖性的抑制作用,其机制可能是通过降低细胞内游离Ca2+浓度发挥其抗增殖作用．高浓度奥曲肽的抗增殖作用亦可能与其抗钙作用有关;各浓度奥曲肽可显著提高小剂量 Tet对胃癌细胞的抑制作用,但与其抗钙作用无关．

AIM： To observe the inhibitory effects of tetrandrine （Tet）, octreotide alone and in combination on the gastric cancer cell lines cultured in vitro, and to explore their possible mechanisms. METHODS： The human gastric cell lines SGC7901 and MKN45 were cultured in vitro. The influences of Tet, octreotide alone and in combination on both kinds of the cells were observed by MTT spectrophotometry, and their effects on the concentration of cytosolic free Ca^2＋ were measured by Fura-2/AM. RESULTS： Octreotide at high concentrations such as 2.4 ×10^-5, 2.4 ×10^-6mol/L, and Tet at concentrations of 10-160 μmol/L significantly inhibited the proliferation of SGC7901 and MKN45 cells, and the inhibitory rates （IR） were 40.76%, 23.2% and 30.5-70.0% for the former, respectively, and 24.9%, 21.7% and 20.4-79.01% for the latter, respectively （P 〈0.05 or P 〈0.01）. Different concentrations of octreotide （2.4 ×10^-6, 2.4 ×10^-9, 2.4 ×10^-12 mol/L） increased the IR of Tet （10 μmol/L） for SGC7901 and MKN45 cells from 32.8% and 27.0% to 50.5% and 60.3%, 55.0% and 47.7%, 67.8% and 63.0%, respectively （P 〈0.05 or P 〈0.01）. The concentrations of free Ca^2＋ in SGC 7901 and MKN 45 cells were significantly reduced as compared with those in the normal controls （394.2±18.4 nmol/L vs 505.0±15.8 nmol/L, 412.1±20.8 nmol/L vs 512.0±16.0 nmol/L, both P 〈0.01）, and similar results were found in octreotide （2.4 ×10^-6 mol/L） group （SGC7901：450.8±20.1 nmol/L, P 〈0.01; MKN45：413.1±10.4 nmol/L, P 〈0.01）. However, octreotide combined with Tet could not reduce the concentration of free Ca^2＋ to a lower degree. CONCLUSION： Tet inhibits the proliferation of gastric cancer cell lines cultured in vitro in a dose-dependent manner, and the reduction of the cytosolic free Ca^2＋ concentration may be involved in its anti-proliferation mechanism. The antiproliferation of octreotide at high concentrations may relate to its anti-calcium effect. Different concentrations of octreotide can enhance the anti- proliferation of Tet at low doses, which may not relate to the reduction of the cytosolic calcium concentration.