ABSTRACT
As a top leading cause of cancer death in many countries, colorectal cancer (CRC) has drawn increasing attention to the study of the pathological mechanism. According to the "cancer stem cell hypothesis", malignancies originate from a small fraction of cancer cells that show self-renewal properties to initiate and sustain tumor growth and tumor metastasis. Therefore, these cancer stem cells (CSC) probably play important roles in tumor recurrence, metastasis, and drug resistance. Previous research reported that lysine-specific histone demethylase 1 (LSD1) maintains cancer stemness through up-regulating stemness markers SOX2 and OCT4. CD133 is believed to be the most robust surface marker for CRC stem cells, however the regulatory effect of LSD1 on stemness of CD133+ CRC has never been reported. In this study, our objectives included: 1) to isolate pure CD133+ and CD133− cells from SW620 cell line; 2) to investigate the effect of LSD1 on the characteristics of CD133+ stem cancer cells by knocking down the target gene. Results suggested that the SW620 cell line had both CD133+ and CD133− subsets. The CD133+ subset exhibited more CSC-like characteristics compared with the CD133− subset with higher viability, colony formation rate, migration and invasion rate, resistance to anti-cancer drugs, and apoptosis in vitro. The CD133+ also induced faster tumor formation and larger tumors in vivo. In the LSD1-knockdown CD133+ cells, the CSC-like characteristics had been all weakened. We conclude that LSD1 was important for CSCs to maintain their "stemness" features, which could be a potential therapeutic target of CRC.
Subject(s)
Humans , Animals , Rats , Neoplastic Stem Cells/drug effects , Colorectal Neoplasms/pathology , Cell Movement/drug effects , Apoptosis/drug effects , Cell Proliferation/drug effects , Histone Demethylases/pharmacology , Neoplastic Stem Cells/metabolism , Gene Expression Regulation, Neoplastic , Blotting, Western , Colony-Forming Units Assay , Cell Line, TumorABSTRACT
Objective To construct rat lysine-specific histone demethylase 1 (LSD1) overexpression plasmids and LSD 1 demethylation fragment disfunction plasmids,and to evaluate their expression levels in HEK293T cells.Methods LSD1 fragments were amplified by PCR,and LSD1 demethylation disfunction fragments were amplified by overlap PCR.Rat-specific LSD1 overexpression plasmids and LSD1 demethylation disfunction plasmids were constructed and verified by agarose gel electrophoresis and sequencing.HEK293T cells were infected using the validated recombinant plasmids and blank vectors,and the stably expressed cells were selected by puromycin.The expression of LSD1 in the stably expressed HEK293T was detected by Western Blot and real-time quantitative PCR.Results The results of agarose gel electrophoresis and sequencing showed that LSD1 overexpression plasmids and LSD1 demethylation disfunction plasmids were successfully constructed.The Western Blot and real-time quantitative PCR results showed that compared with the blank group,the relative expression of LSD1 and mRNA in the LSD1 overexpression group and the LSD1 demethylation disfunction group were up-regulated,and the differences were statistically significant(all P＜0.01).Conclusions The constructed LSD1 overexpression plasmids and LSD1 demethylationi disfunction plasmids can achieve overexpression of LSD1 gene in HEK293T cells.This paper lays a foundation for further study of the relationship between LSD 1 gene and related diseases and demethylation of LSD 1.