Yakisich Juan Sebastian, Azad Neelam, Venkatadri Rajkumar, Kulkarni Yogesh, Wright Clayton, Kaushik Vivek, Iyer Anand Krishnan V
Department of Pharmaceutical Sciences, School of Pharmacy, Hampton University, Hampton, VA 23668, USA.
Stem Cells Int. 2016;2016:5603135. doi: 10.1155/2016/5603135. Epub 2016 Jan 6.
Like with most solid tumors, the presence of a subpopulation of cancer stem cells (CSCs) or cancer stem-like cells (CS-LCs) has been associated with chemoresistance and tumor relapse in lung cancer cells. In the absence of serum, CSCs/CS-LCs have the ability to grow as lung tumorspheres (LTSs), and this system is routinely used for isolation and characterization of putative CSCs/CS-LCs. Methods to isolate LTSs are usually performed in serum-free media supplemented with specific additives such as epidermal growth factor and basic fibroblast growth factor. In this study, we report the generation of LTSs without the addition of any external mitogenic stimulation. LTSs generated in this manner demonstrated several traits usually associated with increased stemness such as elevated expression of the stemness-associated marker Sox2 and increased chemoresistance to conventional anticancer drugs. In addition, we report that the FDA-approved drug Digitoxin, at concentration close to its therapeutic level, decreased the viability of LTSs and downregulated Sox2 independent of the PI3K/AKT pathway. The potential use of LTSs generated without the addition of any external mitogenic stimulation to study the role of specific factor(s) associated with stemness properties is also discussed.
与大多数实体瘤一样，癌症干细胞（CSCs）或癌症干细胞样细胞（CS-LCs）亚群的存在与肺癌细胞的化疗耐药性和肿瘤复发有关。在无血清条件下，CSCs/CS-LCs能够生长形成肺肿瘤球（LTSs），该系统通常用于分离和鉴定假定的CSCs/CS-LCs。分离LTSs的方法通常在添加了特定添加剂（如表皮生长因子和碱性成纤维细胞生长因子）的无血清培养基中进行。在本研究中，我们报告了在不添加任何外部促有丝分裂刺激的情况下生成LTSs。以这种方式生成的LTSs表现出几种通常与干性增加相关的特征，如干性相关标志物Sox2的表达升高以及对传统抗癌药物的化疗耐药性增加。此外，我们报告称，美国食品药品监督管理局（FDA）批准的药物洋地黄毒苷在接近其治疗水平的浓度下，可降低LTSs的活力并下调Sox2，且与PI3K/AKT途径无关。我们还讨论了在不添加任何外部促有丝分裂刺激的情况下生成的LTSs在研究与干性特性相关的特定因子作用方面的潜在用途。
