Wu C Y, Guo X Z, Li H Y
Department of Gastroenterology, Shenyang General Hospital of PLA, No. 83 Wenhua Road, Shenyang, 110016, China.
Clin Transl Oncol. 2015 Mar;17(3):201-8. doi: 10.1007/s12094-014-1211-9. Epub 2014 Sep 9.
KAI1 closely correlates with pancreatic cancer metastasis. There might be some factors that protect the cells from a proliferation inhibition by KAI1 in the solid tumors' microenvironment. Hypoxia and ischemia are the main characteristics of the microenvironment within solid tumors. Whether they affect the KAI1 inhibitory effects on cell proliferation is still unclear.
MiaPaCa-2 human pancreatic cancer cells do not express KAI1 protein. However, after being infected with Ad5-KAI1, they expressed KAI1 protein. We cultured them under hypoxic and serum-free conditions to simulate the solid tumor hypoxic-ischemic microenvironment. The cells were divided into the control, hypoxic, serum-free, and hypoxic with serum-free groups. The proliferation and apoptosis were observed by CCK8 and Annexin V-FITC/PI, respectively. The green fluorescent protein-labeled light chain 3 association with autophagosome membranes was detected by confocal microscopy. The ratio of LC3-II-LC3-I expression level was detected by western blot. Pretreatment of 3-MA was used to inhibit the autophagy. We, then observed whether the hypoxic and serum-free conditions could change the effect of KAI1 on cell survival and whether the pretreatment of 3-MA could inhibit the effect of hypoxic and serum-free conditions on KAI1 function.
Hypoxia and serum-free media effectively reduced the apoptosis and proliferation inhibition caused by KAI1 and was beneficial to the cell survival. 3-MA pretreatment effectively blocked the protective effect of hypoxia and serum-free media on the cells by autophagy block.
Serum-free media and hypoxia protected the MiaPaCa-2 cells from a KAI1-induced apoptosis and proliferation inhibition via autophagy induction.
KAI1与胰腺癌转移密切相关。在实体瘤微环境中，可能存在一些因素使细胞免受KAI1对增殖的抑制作用。缺氧和缺血是实体瘤微环境的主要特征。它们是否影响KAI1对细胞增殖的抑制作用仍不清楚。
MiaPaCa-2人胰腺癌细胞不表达KAI1蛋白。然而，用Ad5-KAI1感染后，它们表达了KAI1蛋白。我们在缺氧和无血清条件下培养它们，以模拟实体瘤缺氧缺血微环境。细胞分为对照组、缺氧组、无血清组和缺氧无血清组。分别通过CCK8和Annexin V-FITC/PI观察细胞增殖和凋亡情况。通过共聚焦显微镜检测绿色荧光蛋白标记的轻链3与自噬体膜的结合情况。通过蛋白质印迹法检测LC3-II-LC3-I表达水平的比值。用3-MA预处理来抑制自噬。然后，我们观察缺氧和无血清条件是否会改变KAI1对细胞存活的影响，以及3-MA预处理是否能抑制缺氧和无血清条件对KAI1功能的影响。
缺氧和无血清培养基有效降低了KAI1引起的凋亡和增殖抑制，有利于细胞存活。3-MA预处理通过阻断自噬有效阻断了缺氧和无血清培养基对细胞的保护作用。
无血清培养基和缺氧通过诱导自噬保护MiaPaCa-2细胞免受KAI1诱导的凋亡和增殖抑制。
