Kaempferol suppresses human gastric cancer SNU-216 cell proliferation, promotes cell autophagy, but has no influence on cell apoptosis

Gastric cancer remains a serious threat to human health worldwide. Kaempferol is a plant-derived flavonoid compound with a wide range of pharmacological activities. This study aimed to investigate the effects of kaempferol on gastric cancer SNU-216 cell proliferation, apoptosis, and autophagy, as well as underlying potential mechanisms. Viability, proliferation, and apoptosis of SNU-216 cells after kaempferol treatment were evaluated using cell counting kit-8 assay, 5-btomo-2′-deoxyuridine incorporation assay, and annexin V-FITC/PI staining, respectively. Quantitative reverse transcription PCR was performed to measure the mRNA expressions of cyclin D1 and microRNA-181a (miR-181a) in SNU-216 cells. Cell transfection was used to down-regulate the expression of miR-181a. The protein expression levels of cyclin D1, bcl-2, bax, caspase 3, caspase 9, autophagy-related gene 7, microtubule-associated protein 1 light chain 3-I (LC3-I), LC3-II, Beclin 1, p62, mitogen-activated protein kinase (MAPK), extracellular regulated protein kinases (ERK), and phosphatidylinositol 3 kinase (PI3K) in SNU-216 cells were detected using western blotting. Results showed that kaempferol significantly suppressed SNU-216 cell viability and proliferation but had no influence on cell apoptosis. Further results suggested that kaempferol significantly induced SNU-216 cell autophagy. The expression of miR-181a in SNU-216 cells after kaempferol treatment was enhanced. Kaempferol significantly inactivated MAPK/ERK and PI3K pathways in SNU-216 cells. Suppression of miR-181a significantly reversed the kaempferol-induced MAPK/ERK and PI3K pathways inactivation in SNU-216 cells. This research demonstrated that kaempferol suppressed proliferation and promoted autophagy of human gastric cancer SNU-216 cells by up-regulating miR-181a and inactivating MAPK/ERK and PI3K pathways.

胃癌仍是全球范围内严重威胁人类健康的重大疾病。山奈酚（Kaempferol）是一种植物来源的黄酮类化合物，具备广泛的药理活性。本研究旨在探讨山奈酚对胃癌SNU-216细胞增殖、凋亡及自噬的影响，并揭示其潜在作用机制。本研究分别采用细胞计数试剂盒-8（cell counting kit-8，CCK-8）实验、5-溴脱氧尿嘧啶核苷（5-bromo-2′-deoxyuridine）掺入实验以及膜联蛋白V-FITC/碘化丙啶（annexin V-FITC/PI）双染色法，检测山奈酚处理后SNU-216细胞的活力、增殖能力与凋亡水平；通过实时定量反转录聚合酶链反应（quantitative reverse transcription PCR，qRT-PCR）测定SNU-216细胞中细胞周期蛋白D1（cyclin D1）与微小RNA-181a（microRNA-181a，miR-181a）的mRNA表达水平；通过细胞转染技术下调miR-181a的表达；采用蛋白质印迹法检测SNU-216细胞中cyclin D1、B细胞淋巴瘤/白血病-2（Bcl-2）、Bcl-2相关X蛋白（Bax）、半胱氨酸天冬氨酸蛋白酶3（caspase 3）、半胱氨酸天冬氨酸蛋白酶9（caspase 9）、自噬相关基因7（autophagy-related gene 7，ATG7）、微管相关蛋白1轻链3-I（LC3-I）、LC3-II、Beclin 1、p62、丝裂原活化蛋白激酶（mitogen-activated protein kinase，MAPK）、细胞外调节蛋白激酶（extracellular regulated protein kinases，ERK）以及磷脂酰肌醇3-激酶（phosphatidylinositol 3 kinase，PI3K）的蛋白表达水平。实验结果显示，山奈酚可显著抑制SNU-216细胞的活力与增殖能力，但对细胞凋亡无显著影响；进一步研究发现，山奈酚可显著诱导SNU-216细胞发生自噬；经山奈酚处理后，SNU-216细胞中miR-181a的表达水平显著上调；山奈酚可显著抑制SNU-216细胞中MAPK/ERK与PI3K信号通路的活化；下调miR-181a的表达可显著逆转山奈酚诱导的SNU-216细胞MAPK/ERK与PI3K信号通路失活。本研究证实，山奈酚可通过上调miR-181a的表达并抑制MAPK/ERK与PI3K信号通路的活化，从而抑制人胃癌SNU-216细胞的增殖并促进其自噬。