ObjectiveTo explore and hypothesize the potential mechanisms of cancer stem cell(CSC) in peritoneal metastasis of gastric cancer. MethodsThe databases of PubMed and CNKI were searched, and relevant literatures were reviewed to draw out systematic hypotheses. ResultsMetastatic cancer stem cell(MCSC) was the subpopulation of CSC with the capacity of metastasis, had still not been well investigated. MCSC transfer was the tendency of migration and planting to specific target tissue by multi-steps of "homing" process. Peritoneal metastasis of gastric cancer was a simplified "homing" process, and we thinked that the key steps were adhesion, migration, and niche establishment of MCSC in peritoneum. That capturing human MCSC of peritoneal metastases in gastric cancer and identifying its stemness feature to determine high tumorigenicity and high invasive ability of it were the important research fields. ConclusionMCSC might play certain role in multiple processes in peritoneal metastasis of gastric cancer, but currently it's lack of relevant researches.
ObjectiveTo investigate the most appropriate culture time with the action of EGF in colon cancer stem cells enrichment by suspension culture.MethodsDLD-1 cells were cultured in serum-free medium containing 20 ng/mL EGF to generate spheroid cells. The time gradient was set to 10 d, 20 d, 30 d and 40 d, the cell proportion of CD133+, CD44+ and CD133+CD44+ were confirmed by flow cytometery. The ability of self-renewal was detected by the sphere forming assay and the limited dilution assay, and the in vitro tumorigenicity of the cells was detected by the colony formation assay.ResultsIn the 30 d group, the proportion of CD133+ and CD133+ CD44+ cells were significantly higher than those in the other groups (allP<0.05), the CD44+ cell was higher than that in the 20 d group (P<0.05), but there was no significant difference with the other two groups (P>0.05). The results of the limited dilution assay and the colony formation assay, the number of spheres in the 30 d or 40 d group was the highest among the 4 groups, and there was no statistical difference between the 30 d group and 40 d group (P>0.05), with statistically significant difference between the 30 d, 10 d and 20 d groups (all P<0.05). The results of the sphere forming assay and the self-renewal ability of 30 d group was significantly higher compared with other groups (all P< 0.05).ConclusionThe cancer stem cells could be enriched more efficiently by suspension culture using 20 ng/mL EGF for 30 days.
ObjectiveTo determine the expressions of Lgr5 protein and Ki-67 protein in gastric cancer tissues, and to analyze the possible function in the carcinogenesis and development of gastric cancer.MethodsThe SABC immunohistochemical method was adopted to examine the expressions of Lgr5 protein and Ki-67 protein in the 69 paraffin slices of gastric cancer from the patients, with the adjacent normal gastric tissue as the control group. The statistical relationship between the expressions of these two kinds of proteins and clinicopathologic features of gastric cancer was examined respectively.ResultsIn the gastric cancer tissue group, the expressions of Lgr5 protein and Ki-67 protein upregulated in comparison to the adjacent normal gastric tissue group [Lgr5 protein: 87.0% (60/69) versus 16.7% (5/30), χ2=45.81, P<0.001; Ki-67 protein: 79.7% (55/69) versus 36.7% (11/30), χ2=17.43, P<0.001]. The expressions of Lgr5 protein and Ki-67 protein all upregulated in the N1–N3 stage groups, lowly differentiated+undifferentiated groups and positive Helicobacter pylori (HP) groups. The expression of Lgr5 protein upregulated in the T3+T4 stage groups in comparison to T1+T2 stage groups, while, no significant relationship was found in the expression of Ki-67 protein and tumor T staging. No significant relationship was found between the gender or metastasis and the expression of these two proteins. There was a positive correlation between the Lgr5 protein expression and the Ki-67 protein expression in the gastric cancer (rs=0.340, P=0.004).ConclusionsIn the development progress of gastric cancer, the Lgr5 protein might get involved in the mechanism of tumor invasion, lymph nodal metastasis, and low differentiation. Ki-67 protein might get involved in the mechanism of lymph nodal metastasis and low differentiation. The two proteins, together with the HP infection, might play a synergistic role in tumorigenesis and development.
ObjectiveTo isolate cancer stem cells (CST) from human breast cancer cell line (MCF-7) and study their sensitivity toward oxidative stress.MethodsMCF-7 cells were cultured in serum-free suspension culture medium to identify cells forming the sphere phenotype. The morphological changes of MCF-7 cells were observed by inverted phase contrast microscope (compared with MCF-7 cells cultured in serum-free suspension culture medium). The expression of CST marker CD133 was detected by immunocytochemical staining in CST cell spheres (experimental group) with a diameter of 100 μm and MCF-7 cells (control group) with a fusion degree of 70%. The positive rate of CD133 was detected by flow cytometry in the third generation of tumor cells with diameter of 150 μm. The second generation of tumor globular cells (experimental group) with diameter of 150 μm and corresponding MCF-7 cells (control group) were taken to be damaged by 50 mol/L H2O2 for 120 minutes. The expression of DNA damage marker histone H2AX phosphorylation (γH2AX) was detected by immunocytochemical staining.ResultsInverted phase contrast microscopy showed that MCF-7 cells grew initially in a single-cell adherent state, then aggregated and grew in serum-free suspension culture medium, and finally formed CST cell spheres, while the control MCF-7 cells cultured in MCF-7 cell culture medium grew extensively and could not grow in suspension. Fluorescence microscopy showed that the expression of CD133 in MCF-7 cells of control group was negative, while that in experimental group was positive. Flow cytometry showed that CD133 was positive in CST cells, and the positive rate was 92%. Inverted fluorescence microscopy showed that the expression of γH2AX in CST tumor spheres of experimental group was significantly lower than that in MCF-7 cells of control group after 120 minutes of H2O2 injury.ConclusionSerum-free suspension culture medium can produce globular CST cells from MCF-7 tumor cell line, which have strong antioxidant damage.
Objective To analyze the advances of cancer stem cell (CSC) in recent years, and to propose a prospect for CSC research and cancer therapy. Methods Articles about important advances of CSC theory and cancer therapy were reviewed, and then selected and summarized. Results In 2001, CSC was first put forward as a concept, till now, which has been confirmed in many tissues. In recent years, efforts were dedicated to such topics including: identification of CSC in sol id tumors, the origin of CSC, its niche and growth mechanism, cancer therapy, etc. According to the CSC theory, traditional therapeutic methods have deficiencies, and new treatment targeting CSC may thoroughly el iminate tumors. Conclusion At present, CSC theory is still controversial, while it proposed revolutionary methods and directions for the therapy of cancer.
ObjectiveTo explore the expression of genes related to hepatocellular carcinoma (HCC) stem cells and their prognostic correlation by using weighted gene co-expression network analysis (WGCNA).MethodsFirstly, the transcriptome sequencing (RNA-seq) and clinical data of HCC were downloaded from the public database the Cancer Genome Atlas (TCGA), and the mRNA expression-based stiffness index (mRNAsi) table of cancer stem cells was downloaded and sorted out to analyze the relationship between mRNAsi and pathological grade and prognosis of HCC. The mRNAsi of HCC was downloaded and the prognostic value of mRNAsi was discussed. Then we used WGCNA to screen the key modules related to liver cancer stem cells (LSCS). Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes were used for the functional and pathway enrichment analysis. The online database STRING was used to construct hub genes coding proteins interaction (PPI) network and screen key genes. Finally, the key genes were analyzed for expression differences and expression correlations. The online database Kaplan-Meier plotter was used for survival analysis and verified.ResultsmRNAsi was significantly upregulated in cancer tissues (P<0.001), and increased with the increase of pathological grade of HCC (P=0.001). The mortality rate of the higher mRNAsi group was higher than that of the lower mRNAsi group (P=0.006). GO analysis found that hub genes were mainly involved in biological processes, such as mitosis and DNA replication, and KEGG showed that hub genes were enriched in cell cycle, DNA mismatch repair, oocyte meiosis, and other signaling pathways. We screened 10 key genes (included CCNB1, CDC20, CDCA8, NDC80, KIF20A, TTK, CDC45, KIF15, MCM2, and NCAPG) related to mRNAsi of HCC based on WGCNA. The key genes were highly expressed in the tumor samples compared to the normal samples. In addition, there was a strong interaction between proteins of these key genes (P<0.05), a strong co-expression relationship at the transcriptional level, and all related to prognosis of HCC.ConclusionsmRNAsi plays an important role in the occurrence and development of HCC. Ten key genes related to LSCS were screened, which may act as therapeutic targets for inhibiting the stem cell characteristics of HCC.
ObjectiveTo detect expressions of Lgr5 and E-cadherin (E-cad) proteins in gastric cancer tissues and analyze their relationships with the clinicopathologic characteristics and prognosis of patients with gastric cancer.MethodsThe expressions of Lgr5 and E-cad proteins in the 69 patients with gastric cancer and adjacent normal gastric mucosa tissues were measured by the immunohistochemical SABC method, and the relationships between the Lgr5 or E-cad protein expression in the gastric cancer tissues and the clinicopathologic characteristics and the survival of patients with gastric cancer were analyzed.ResultsThe expressions of Lgr5 and E-cad proteins were positive in 60 cases (87.0%) and 30 cases (43.5%) of gastric cancer tissues, respectively, and in 5 cases (16.7%) and 30 cases (100%) of adjacent normal gastric mucosa tissues. There was a significant difference in the positive rate of Lgr5 or E-cad protein expression in the different tissues, respectively (Lgr5 protein: χ2=45.814, P<0.001; E-cad protein: χ2=11.249, P=0.001). The positive rates of Lgr5 and E-cad protein expressions in the gastric cancer were related to the degree of differentiation and the depth of invasion. Meanwhile the positive rate of Lgr5 protein expression in the gastric cancer tissue was also related to the lymph node metastasis and Helicobacter pylori infection, while the positive rate of E-cad protein expression was not related to these (P>0.05). The 5-year total survival time had no significant difference in the patients between with positive and with negative expressions of Lgr5 protein (χ2=1.819, P=0.117), which had a significant difference in the patients between with positive and with negative expressions of E-cad protein (χ2=5.814, P=0.016). The positive expression of Lgr5 was negatively correlated with that of E-cad (rs=−0.355, P=0.003).ConclusionsLgr5 protein may get involved in the mechanism of tumor invasion, lymph nodal metastasis, and low differentiation, while no relationship between the Lgr5 protein and prognosis has been confirmed. E-cad protein may get involved in the mechanism of tumor invasion and affect the prognosis of patients.
Increasing evidence suggests that many types of cancers contain a population of cells that display stem cell properties. These cells are called cancer stem cells （CSCs），which are closely related to tumor initiation，growth，metastasis and chemoresistance. CSCs are also found in esophageal squamous cell carcinoma （ESCC）. These cells are characterized by potential of self-renewal and differentiation，tumor formation in nude mice and chemotherapy resistance，and thus may play an important role in targeted cancer therapies. Current methods for culturing and sorting CSCs in ESCC mainly include fluorescence activated cell sorting （FACS），magnetic activated cell sorting （MACS），suspension culture，and side population （SP） cell sorting. In this review，we focus on current research methods for CSCs in ESCC，their biological characteristics and areas for improvement. We believe that a combination of multiple cell-surface makers is needed for research of CSCs in ESCC.