Chemotherapy sorting can be used to identify cancer stem cell populations

Homeobox Gene Expression Dysregulation as Potential Diagnostic and Prognostic Biomarkers in Bladder Cancer

Homeobox genes serve as master regulatory transcription factors that regulate gene expression during embryogenesis. A homeobox gene may have either tumor-promoting or tumor-suppressive properties depending on the specific organ or cell lineage where it is expressed. The dysregulation of homeobox genes has been reported in various human cancers, including bladder cancer. The dysregulated expression of homeobox genes has been associated with bladder cancer clinical outcomes. Although bladder cancer has high risk of tumor recurrence and progression, it is highly challenging for clinicians to accurately predict the risk of tumor recurrence and progression at the initial point of diagnosis. Cystoscopy is the routine surveillance method used to detect tumor recurrence. However, the procedure causes significant discomfort and pain that results in poor surveillance follow-up amongst patients. Therefore, the development of reliable non-invasive biomarkers for the early detection and monitoring of bladder cancer is crucial. This review provides a comprehensive overview of the diagnostic and prognostic potential of homeobox gene expression dysregulation in bladder cancer.

The Interaction between DNMT1 and High-Mannose CD133 Maintains the Slow-Cycling State and Tumorigenic Potential of Glioma Stem Cell

The quiescent/slow-cycling state preserves the self-renewal capacity of cancer stem cells (CSCs) and leads to the therapy resistance of CSCs. The mechanisms maintaining CSCs quiescence remain largely unknown. Here, it is demonstrated that lower expression of MAN1A1 in glioma stem cell (GSC) resulted in the formation of high-mannose type N-glycan on CD133. Furthermore, the high-mannose type N-glycan of CD133 is necessary for its interaction with DNMT1. Activation of p21 and p27 by the CD133-DNMT1 interaction maintains the slow-cycling state of GSC, and promotes chemotherapy resistance and tumorigenesis of GSCs. Elimination of the CD133-DNMT1 interaction by a cell-penetrating peptide or MAN1A1 overexpression inhibits the tumorigenesis of GSCs and increases the sensitivity of GSCs to temozolomide. Analysis of glioma samples reveals that the levels of high-mannose type N-glycan are correlated with glioma recurrence. Collectively, the high mannose CD133-DNMT1 interaction maintains the slow-cycling state and tumorigenic potential of GSC, providing a potential strategy to eliminate quiescent GSCs.

Time-lapse microscopic observation of non-dividing cells in cultured human osteosarcoma MG-63 cell line

Cancer stem cells resemble normal tissue-specific stem cells in many aspects, such as self-renewal and plasticity. Like their non-malignant counterparts, cancer stem cells are suggested to exhibit a relative quiescence. The established cancer cell lines reportedly harbor slow-proliferating cells that are positive for some cancer stem cells markers. However, the fate of these cells and their progeny remains unknown. We used time-lapse microscopy and the contrast-based segmentation algorithm to identify and monitor actively dividing and non-dividing cells in human osteosarcoma MG-63 cell line. Within the monitored field of view the non-dividing cells were represented by three cells that never divided, and one cell that attempted to divide, but failed cytokinesis, and later, after significantly prolonged division, produced the progeny with enlarged segmented nuclei, thus pointing to a possible mitotic catastrophe. Together, these cells initially constituted about 6.2% of the total number of seeded cells, yet only 0.02% of all cells at the end of the observation period when cells became confluent. Non-dividing cells were characterized by rounded shape, dark nuclei, random cytoplasmic streaming and subtle oscillatory movement, however, they did not migrate and rarely formed cell-cell contacts as compared to actively dividing cells. Our data indicate that the observed non-dividing MG-63 cells do not have a growth advantage over other cells and, therefore, they do not contribute to the cancer stem cells pool.

A modified method by differential adhesion for enrichment of bladder cancer stem cells

Purpose:

In a previous study the vaccine was effective against bladder cancer in a mouse model. However, a small portion of tumors regrew because the vaccine could not eliminate bladder cancer stem cells (CSCs). In this study, we showed a modified method for the isolation of bladder CSCs using a combination of differential adhesion method and serum-free culture medium (SFM) method.

Materials and Methods:

Trypsin-resistant cells and trypsin-sensitive cells were isolated from MB49, EJ and 5637 cells by a combination of differential adhesion method and SFM method. The CSCs characterizations of trypsin-resistant cells were verified by the flow cytometry, the western blotting, the quantitative polymerase chain reaction, the resistance to chemotherapy assay, the transwell assay, and the tumor xenograft formation assay.

Results:

Trypsin-resistant cells were isolated and identified in CSCs characters, with high expression of CSCs markers, higher resistance to chemotherapy, greater migration in vitro, and stronger tumorigenicity in vivo.

Conclusion:

Trypsin-resistant cells displayed specific CSCs properties. Our study showed trypsin-resistant cells were isolated successfully with a modified method using a combination of differential adhesion method and SFM method.

Endogenous miRNA Sponge LincRNA-ROR promotes proliferation, invasion and stem cell-like phenotype of pancreatic cancer cells

The long intergenic non-coding RNA, regulator of reprogramming (linc-ROR) is an oncogene and plays a key role in the embryonic stem cell maintenance and is involved in cancer progression. The objective of this study was to analyze linc-ROR expression in pancreatic ductal adenocarcinoma (PDAC) and determine the regulation effects of linc-ROR on proliferation and invasion of cancer cells, as well as properties of cancer stem-like cells (CSLCs). In this study, we found that linc-ROR was up-regulated in PDAC tissues and related to poor prognosis. Linc-ROR knockdown in pancreatic cancer cells inhibited cell growth and arrested in G1 phrase. Suppressed linc-ROR expression also attenuated cancer cell migration, invasion, and epithelial-mesenchymal transition. We observed that linc-ROR expression was increased in CSLCs. Importantly, linc-ROR knockdown impaired the properties and tumorigenesis of pancreatic CSLCs in vivo. Mechanistically, we found that linc-ROR functioned as a competing endogenous RNA (ceRNA) to several tumor suppressor microRNAs, particularly some members of let-7 family. We conclude that, as a crucial oncogene, linc-ROR promotes cell proliferation, invasiveness and contributes to stem cell properties of CSLCs in PDAC via acting as a ceRNA to regulate function of microRNAs. The linc-ROR is a potential therapeutic target for PDAC.

Development of a therapy against metastatic bladder cancer using an interleukin-2 surface-modified MB49 bladder cancer stem cells vaccine

Introduction

In previous study the streptavidin interleukin-2 (SA-IL-2)-modified MB49 vaccine was effective against bladder cancer in a mouse model. However, a small portion of tumors regrew because the vaccine could not eliminate MB49 bladder cancer stem cells (MCSCs). Accordingly, we developed a SA-IL-2-modified MCSCs vaccine and evaluated its antitumor effects.

Methods

MCSCs were isolated and identified in cancer stem cells (CSCs) characters, with high expression of CSCs markers, higher resistance to chemotherapy, greater migration in vitro, and stronger tumorigenicity in vivo. The SA-IL-2 MCSCs vaccine was prepared and its bioactivity was evaluated. The protective, therapeutic, specific and memory immune response in animal experiments were designed to identify whether the vaccine elicited antitumor immunity and acted against metastatic bladder cancer.

Results

MCSCs had higher level of CD133 and CD44, less susceptibility to chemotherapy, more pronounced migration and greater tumorigenic ability. The successfully prepared SA-IL-2 MCSCs vaccine inhibited the tumor volume and prolonged mice survival in animal experiments. The expression of IgG, the population of dendritic cells, CD8⁺ and CD4⁺ T cells were highest in the experimental group than in the four control groups.

Conclusions

The SA-IL-2 MCSCs vaccine induced an antitumor immune response and was used to eliminate MCSCs to prevent tumor regrowth.

Cancer stem cell detection and isolation

Only 10 % of cancer-related deaths result from primary tumors; most are caused by metastatic tumors. It is believed that the metastatic power of tumor cells is attributed to features of a stem cell-like subpopulation of tumor cells known as cancer stem cells (CSCs). Cancer stem cells are resistant to chemotherapeutic treatments and can induce dormancy in tumor cells for long periods. Detection, isolation, and characterization of CSCs in solid tumors are hallmarks of cancer-targeted therapies in recent years. There are inevitable similarities between normal and cancer stem cells; therefore, finding specific methods or markers to differentiate them is critical to cancer therapies. Considering CSCs involvement in tumor relapse and chemotherapeutic resistance, identification of such cells in tumors is imperative for effective targeted therapy. The present review introduces practical and specific protocols used to isolate CSCs from solid tumors from colon, esophagus, liver, breast, brain, and cervix.

A modified method for isolation of bladder cancer stem cells from a MB49 murine cell line

BACKGROUND

The vaccine was efficiently effective against bladder cancer in earlier studies. However, a part of the mouse bladder tumour regrew due to regression after a period of time as the cancer stem cells could not be eliminated. In this study, we showed a modified method for the isolation of MB49 bladder cancer stem cells (MCSCs).

METHODS

Through a comparison of different serum-free culture mediums (SFM), MCSCs were isolated by a combination of the limited dilution method and the optimal SFM method. The characterizations of MCSCs were verified by the fluorescence activated cell sorting, the quantitative polymerase chain reaction, the western blotting, the cell proliferation assay, the soft agar assay, the transwell assay, the resistance to chemotherapy assay and the tumor xenograft formation assay.

RESULTS

The optimal SFM contained a RPMI1640+ epidermal growth factor (20 ng/ml), a basic fibroblast growth factor (20 ng/ml), a leukemia inhibitory factor (20 ng/ml), a B-27 serum-free supplement (20 μl/ml), and a bovine serum albumin (4 μg/ml). MCSCs possessed the high expression of cancer stem cell markers (CD133, CD44, OCT4, NANOG, and ABCG2) and the ability of differentiation. In functional comparisons, MCSCs had higher proliferative abilities, lower susceptibility to chemotherapy, greater migration in vitro, and stronger tumorigenic abilities in vivo.

CONCLUSION

MCSCs displayed specific cancer stem cells properties. Our study showed MCSCs were isolated successfully with a modified method using a combination of limited dilution and SFM methods.