Identification of a Cancer Stem-like Population in the Lewis Lung Cancer Cell Line

An-Mei Zhang,Jia Liu,Quan Yao,Zheng-Tang Chen,Xin-Xin Wang,Sheng Lin,Bo Zhu,Ye Fan,Hu Ma,Cong-Hui Zhu,Jian-Guo Sun

doi:10.7314/apjcp.2012.13.3.761

An-Mei Zhang, Jia Liu + Show 9 more

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https://doi.org/10.7314/apjcp.2012.13.3.761

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Abstract

Although various human cancer stem cells (CSCs) have been defined, their applications are restricted to immunocompromised models. Developing a novel CSC model which could be used in immunocompetent or transgenic mice is essential for further understanding of the biomolecular characteristics of tumor stem cells. Therefore, in this study, we analyzed murine lung cancer cells for the presence of CSCs. Side population (SP) cells were isolated by fluorescence activated cell sorting, followed by serum-free medium (SFM) culture, using Lewis lung carcinoma cell (LLC) line. The self-renewal, differentiated progeny, chemosensitivity, and tumorigenic properties in SP and non-SP cells were investigated through in vitro culture and in vivo serial transplantation. Differential expression profiles of stem cell markers were examined by RT-PCR. The SP cell fraction comprised 1.1% of the total LLC population. SP cells were available to grow in SFM, and had significantly enhanced capacity for cell proliferation and colony formation. They were also more resistant to cisplatin in comparison to non-SP cells, and displayed increased tumorigenic ability. Moreover, SP cells showed higher mRNA expression of Oct-4, ABCG2, and CD44. We identified SP cells from a murine lung carcinoma, which possess well-known characteristics of CSCs. Our study established a useful model that should allow investigation of the biological features and pharmacosensitivity of lung CSCs, both in vitro and in syngeneic immunocompetent or transgenic/knockout mice.

Highlights

Despite of the great improvements in reducing mortality rates and improving prognosis over the past decades, lung cancer remains the leading cause of tumorrelated death in the world
Developing a novel cancer stem cells (CSCs) model which could be used in immunocompetent or transgenic mice is essential for further understanding of the biomolecular characteristics of tumor stem cells
Side population (SP) cells were isolated by fluorescence activated cell sorting, followed by serum-free medium (SFM) culture, using Lewis lung carcinoma cell (LLC) line

Summary

Introduction

Despite of the great improvements in reducing mortality rates and improving prognosis over the past decades, lung cancer remains the leading cause of tumorrelated death in the world. Non-small cell lung cancer (NSCLC) is the most common type of lung cancer, which includes adenocarcinoma, squamous cell carcinoma, and large cell carcinoma (Petersen and Petersen, 2001; Collins et al, 2007). The current treatments for NSCLC are largely inadequate, and the survival for those patients is often measured in months (Jemal et al, 2004). There was increasing evidence indicating that the maintenance and spreading of a variety of tumors was sustained by a small subset of cancer cells - cancer stem cells (CSCs). These cells possess ability to selfrenew, unlimited proliferation potential, and capacity to generate differentiated cells which constitute the major tumor population (Reya et al, 2001). Isolation and characterization of CSCs may offer new therapeutic strategies against malignant tumors

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