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.
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.
Objective To review the role of mTOR signal pathway in chemo-resistance of gastric cancer. Methods Domestic and international publications related mTOR signal pathway in chemo-resistance of gastric cancer in recent years were collected and reviewed. Results mTOR was a central signaling molecule of mTOR signal pathway， which regulated key cellular processes such as cell growth， cell proliferation， cell metabolism， and angiogenesis. Signaling molecules of mTOR signal pathway were overexpressed in gastric cancer. Moreover， mTOR signal pathway might play an important role in chemo-resistance of gastric cancer， and tumor stem cells were involved in it too. Conclusion As mTOR signal pathway plays an important role in chemo-resistance of gastric cancer， the combination of mTOR inhibitors and chemotherapy drugs may overcome the chemo-resistance of gastric cancer.
Objective To summarize the advancement of breast cancer stem cells and genotyping and analyze the correlation between the two. Methods Relevant literatures about breast cancer stem cells and genotyping, which were published recently were collected and reviewed. Results Cancer stem cell origin theory was supported by researches of correlation between breast cancer stem cells and genotyping, which also explained the complexity of intrinsic subtypes and heterogeneity of breast cancer. Conclusions A new way can be detected to study the formation mechanism and biological characteristics of breast cancer at the cellular and molecular level by researches of correlation between breast cancer stem cells and genotyping, which are expected to provide new strategies and tools for diagnosis and treatment of breast cancer.
Objective To isolate and purify the melanoma stem cells (MSC) in choroidal melanoma OCM-1 cells. Methods OCM-1 cells were resuscitated, and after cultured in standard Dubecco's modifided Eagle's medium (DMEM)/F12, they were cultured in serum-free medium (SFM). The cultured MSC were isolated and purified, and the positive rate of CD133, the specific markers of neurostem cells, was observed by flow cytometry (FCM). The 6th generation of the cells were stained by musashi-1 immunocytochemistry, and the rate of the positive cells was observed under the microscope. Results After the Adherent OCM-1 cells cultured in SFM, the number of the adherent number decreased obviously. The cells at the 6th generation grew as the suspended gobbets, which represented the typical grow manner of the stem cells. Positive CD133 could be found in the cells of different generations, which was 2.5％, 21.7％, and 57.8％ in the non-isolated OCM-1 cells, the 1st generation of isolated cells, and the 2nd generation cells, respectively. The positive rate of CD133 in the cells at the sixth generation was 79.8% with b positive expression of musashi-1. Conclusion MSC is in the human choroidal melanoma OCM-1 cells. The suspended stem cells may be purified by limited differentiation and serial passage in SFM. (Chin J Ocul Fundus Dis, 2007, 23: 87-90)