Electron microscopic analysis of different cell types in human pancreatic cancer spheres
Electron microscopic analysis of different cell types in human pancreatic cancer spheres
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DOI：
10.3892/ol.2017.7554
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发表时间：
2018-02-01
期刊：
影响因子：
2.9
通讯作者：
Aida, Junko
中科院分区：
文献类型：
--
作者：
Ishiwata, Toshiyuki;Hasegawa, Fumio;Aida, Junko
癌症干细胞（CSC）具有多能性和自我更新能力，有助于癌症的发生和转移，并负责对化疗和放疗的抵抗。胰腺导管腺癌（PDAC）是一种侵袭性癌症，与远处转移和复发的高发生率相关。球体形成揭示了非贴壁条件下的细胞增殖，通常用于识别 CSC；球体的数量、面积和体积的测量用于估计 PDAC 细胞的干度。然而，尚未对此类球体进行详细的形态分析。本研究的目的是通过扫描电子显微镜 (SEM) 和透射电子显微镜 (TEM) 检查从 PANC-1 人胰腺癌细胞中分离的球体的形态。 PANC-1 细胞在接种于超低附着平板后 1 周内形成圆形至不规则椭圆形球体。与贴壁细胞相比，这些球体表现出更高水平的 CSC 标记表达，包括巢蛋白、性别决定区 Y-box 2 和含有变异外显子 9 的 CD44。扫描电镜分析显示，这些球体呈现出葡萄状的外观，其中含有表面光滑或粗糙的癌细胞。同样，TEM 分析检测到球体内具有不同表面类型的癌细胞：那些表面光滑、不规则的大突起、突出物和少量微绒毛的癌细胞，以及遍布整个细胞表面的许多微绒毛的癌细胞。癌细胞之间的这些形态差异可能表明球体内从 CSC 到非 CSC 的分化过程的不同阶段。
Cancer stem cells (CSCs), which are pluripotent and self-renewable, contribute to the initiation and metastasis of cancer, and are responsible for resistance to chemotherapy and radiation. Pancreatic ductal adenocarcinoma (PDAC) is an aggressive type of cancer that is associated with a high incidence of distant metastasis and recurrence. Sphere formation reveals cell proliferation under nonadherent conditions and is commonly used to identify CSCs; measurements of the number, area and volume of the spheres are used to estimate sternness of PDAC cells. However, detailed morphological analysis of such spheres has not been performed. The aim of the present study was to examine the morphology of spheres isolated from PANC-1 human pancreatic cancer cells via scanning electron microscopy (SEM) and transmission electron microscopy (TEM). PANC-1 cells formed round to irregular oblong spheres within 1 week following seeding in ultra-low-attachment plates. These spheres exhibited higher levels of expression of CSC markers, including nestin, sex determining region Y-box 2, and CD44 containing variant exon 9, compared with adherent cells. SEM analysis revealed that the spheres exhibited a grape-like appearance, harboring cancer cells with smooth or rough surfaces. Similarly, TEM analysis detected cancer cells with varying surface types within the spheres: Those with smooth surfaces, irregular large protrusions, protrusions and a small number of microvilli, and those with many microvilli throughout the entire cell surface. These morphological differences among cancer cells may be indicative of different stages in the differentiation process, from CSCs to non-CSCs, within the spheres.