Resistance mechanisms of tumour-initiating cells / 国际外科学杂志

Tumor initiating cells are the source of the tumor,which have the characteristics of stem cells,such as self-renewal capacity,unlimited proliferation,multi-directional differentiation,DNA repair activity and resistance to apoptosis.The tumor initiating cells involved in chemotherapy drug resistance,traditional chemotherapy drugs is difficult to kill them,studies have shown that the tumor initiating cells involved in chemotherapy drug resistance.Tumor initiating cells are the significant factor of drug resistance and relapse in the tumor.tumor initiating cells resistance mechanism is complex,not only involved in tumor generally resistant characteristics,but kept natural resistance properties of stem cells.Tumor initiating cells resistant mechanism is controversial.This review introduces the resistance mechanisms of tumor-initiating cells both in tumor initiating cells-intrinsic and tumor initiating cells-extrinsic aspects based on the domestic and international relevant literatures.By revealing the drug resistance mechanism,it can be used to predict the effect of clinical chemotherapy,and now the article will review the research progress of the drug resistance mechanism of tumor initiating cells.

Trending Speculations of Tumor-Initiating Cells in Squamous Cell Cancers of Head and Neck

Tumor-initiating cells are a diminutive subpopulation of stem cells that have ability of long term self-renewal and generation of varied traits of tumor cell population. Understanding the concept of tumor-initiating cells may have a great implicative intimation for our comprehension of cancer pathobiology and for the delineation of new therapies directed towards these stem cells. The present review is an endeavor to conceptualize the role of tumor-initiating cells in the Squamous Cell Cancers (SCC) of head and neck, their role in tumorigenesis and the possible supplementary approach in the latest treatment modalities.

Influence of CD133

Objective: To investigate the influence of CD133

Influence of CD133+expression on patients' survival and resistance of CD133+cells to anti-tumor reagents in gastric cancer

Objective: To investigate the influence of CD133+expression on patients' survival and resistance of CD133+cells to anti-tumor agents in gastric cancer (GC). Methods: Influence of CD133 expression on prognosis was analyzed employing sam-ples from patients with GC. GC cell lines were utilized to separate CD133+and CD133?subpopulations by immunomagnetic separation and to analyze the biological features of two subpopulations in vitro and in vivo, especially in resistant to anti-tumor reagents and its apoptotic mechanism. Results: The lower CD133+group showed a significantly better survival compared with the higher CD133+group. The highest content of CD133+subpopulations for KATO-III cells had stronger proliferative ability than CD133?subpopulations. A single CD133+cell was capable of generating new cell colony and the tumorigenicity rate in nude mice was 100% for CD133+ clonal spheres or for CD133+ cells, but 0% for CD133? cells. Furthermore, the higher expression levels of Oct-4, Sox-2, Musashi-1 and ABCG2 in CD133+ clonal spheres were identified compared with CD133+ cells or CD133? cells. Under the treatment of anti-tumor reagents, CD133+ cells had lower suppression rates compared with CD133? cells while lower level of Bcl-2 and higher level of Bax were found in CD133+cells compared with CD133?cells. Conclusions: The patients with lower CD133+expression had a better survival. Enriched CD133+ cells in clonal sphere shared the ability to be self-renewable, proliferative, tumorigenic and resistant to anti-tumor agents as probably regulated by Bcl-2 and Bax.

Presença de marcadores de células-tronco em linhagens celulares humanas de câncer de mama: possível valor em diagnóstico, prognóstico e terapía / Analysis of stem cells markers in human breast cancer cell lines

O câncer de mama é a doença maligna que mais acomete as mulheres no mundo. Apesar dos inúmeros tratamentos, o óbito se deve principalmente à doença metastática que pode se desenvolver a partir do tumor primário. Esta progressão tumoral decorre da dificuldade de se estabelecer um prognóstico mais preciso. Atualmente, a teoria de células iniciadoras de tumor vem sendo estudada para tentar explicar a biologia do câncer e descrever novos alvos para prognósticos e terapias. O carcinoma mamário foi o primeiro tumor sólido para o qual foi identificada uma subpopulação celular, definida como CD44+/CD24-, apresentando as características de células iniciadoras tumorais. Embora este fenótipo venha sendo muito utilizado para descrever as células iniciadoras tumorais de mama, muitos trabalhos tem questionado a relevância clínica desses marcadores, enfatizando que outros marcadores devem ser identificados. Assim, o objetivo deste trabalho é analisar e caracterizar marcadores de células-tronco que possam estar relacionados com o grau de malignidade no modelo de câncer de mama. Inicialmente, analisou-se a expressão de 10 marcadores de células-tronco em diferentes linhagens de câncer de mama que apresentam graus crescentes de malignidade. O CD90 foi selecionado devido à alta expressão desse marcador na linhagem mais agressiva Hs578T. Para a caracterização deste marcador, realizou-se ensaios funcionais, através do silenciamento do CD90 na linhagem tumorigênica Hs579T e sua superexpressão na linhagem não-tumorigênica MCF10A. As linhagens celulares geradas foram caracterizadas quanto ao crescimento celular, potencial invasivo e metastático. Foi possível observar que houve uma alteração da morfologia nas linhagens transformadas com o CD90 e, também, um maior tempo de dobramento na linhagem Hs578T-CD90- e um menor na MCF10A-CD90+. Além disso, a linhagem MCF10-CD90+ foi capaz de crescer independentemente de EGF. Através da análise da via EGF, foi possível observar que houve um aumento da expressão da forma fosforilada do receptor e dos fatores Erk, c-Jun, e Jnk na linhagem MCF10A-CD90+ e uma diminuição dos mesmos na linhagem Hs578T-CD90-. A análise da atividade do elemento responsivo do fator de transcrição AP1 comprovou que a via de EGF é funcional na linhagem MCF10-CD90+. Também foram analisados os marcadores de transição epitélio-mesenquimal, verificando-se aumento da expressão dos marcadores mesenquimais na linhagem MCF10A-CD90+ e diminuição na linhagem Hs578T-CD90-. Os ensaios in vitro de invasão mostraram que as células MCF10-CD90+ são capazes de migrar e invadir e as células Hs578T-CD90- apresentam diminuição significativa da habilidade de migração e invasão. Além disso, os ensaios de metástase in vitro e in vivo, mostraram que a superexpressão de CD90 levou à malignização das células MCF10A. Por outro lado, a linhagem Hs578T-CD90- apresentou menor potencial metastático in vitro. Portanto, neste trabalho, pela primeira vez, o CD 90 foi caracterizado funcionalmente como um marcador envolvido na transformação maligna do carcinoma mamário, contribuindo, assim, para melhor entendimento da biologia do câncer de mama e para que se possa desenvolver novas ferramentas de diagnóstico/prognóstico e novos protocolos clínicos e terapêuticos

Breast cancer is the malignant disease which affects the highest number of women in the world. In spite of the numerous treatments available, death is primarily due to the metastatic disease that may develop from the primary tumor. This tumor progression occurs because of the difficulty in establishing an accurate diagnosis/prognosis. Currently, the tumor initiating cells theory is being applied in an attempt to explain cancer biology and to unveil new diagnostic and therapeutic targets. Mammary carcinoma was the first solid tumor in which a cellular subpopulation, defined as CD44+/CD24-, was associated with tumor initiating cells. Although this phenotype has been widely used to describe breast tumor initiating cells, several studies have questioned the clinical relevance of these markers, emphasizing that additional markers should be identified. The objective of the present study is to analyze and characterize stem cell markers that may be related to malignancy stages in the breast cancer model. Initially, the expression of 10 stem cell markers was analyzed in different breast cancer cell lines displaying different malignancy grades. CD90 was selected due to its high expression levels in the most aggressive cell line, namely: Hs578T. In order to further characterize this marker, a functional study was performed in which CD90 was silenced in the Hs578T tumorigenic cell line and overexpressed in the non-tumorigenic MCF10A cell line. The resulting cell lines were characterized relative to growth rate and invasive and metastatic potential. A change in morphology readily was observed in the cell lines overexpressing CD90. In addition, the Hs578T-CD90-cell line presented an increased doubling time (DT), while the MCF10A-CD90+ cell line displayed a lower DT.. Furthermore, MC10-CD90+ cells were able to grow in the absence of EGF. Analysis of components of the EGF pathwayrevealed increased expression levels of the phosphorylated form of Erk, c-Jun and Jnk receptors in the MCF10-CD90+ cell line, while Hs578T-CD90- cells presented decreased expression of the same factors and receptors. Analysis of the activity of the AP1 responsive element allowed confirmation that the EGF pathway is functional in the MCF10-CD90+. . Epithelial-mesenquimal transition markers presented increased expression levels in the MCF10A-CD90+ cell line, accompanied by decreased expression levels in Hs578T-CD90- cells. In vitro invasion assays showed that MCF10A-CD90+ cells are capable of migrating and invading, while Hs578T-CD90- cells presented a significant decrease in their ability to migrate and invade. Additionally, in vitro and in vivo metastasis assays showed that malignization ensued upon overexpression of CD90 in MCF10A cells and a lower tendency to form metastasis in vitro was observed for the Hs578T-CD90- cell line. Therefore, the present study presents, for the first time in the literature, the functional characterization of CD90 as a genetic marker involved in the malignant transformation of mammary carcinoma, leading to a better understanding of the breast cancer biology, which may, in turn, lead to the development of new clinical and therapeutic protocols

Resistance of CD133 + subset to chemotherapy drugs and its expressions of apoptosis genes in gastric cancer / 国际外科学杂志

Objective To study the resistances of CDl33 + subset purified from gastric cancer cell line to chemotherapy drugs and the mechanism of this resistance regarding to the mRNA expressions of both Bcl-2 and BAX in relation to the relative apoptotic genes.Methods CD133 + subset and CD133-subset were purified from KATOⅢ cell linc by magnetic activated cell sorting.The proliferating ability of these two subsets resistantnt to 5-FU,Cisplatin(DDP,PDD) and Etoposide was checked and compared by CCK-8 test.The apoptotic changes of these two subsets regarding to the expression of mRNA of both Bcl-2 and BAX were also analized by RT-PCR.Results In CD133 + subset,the contant percentage of CD133 + expression rate was 90％ via analysis of flow cytometye.Twelve hours after treatment of5-FU,DDP and VP-16,the cells in both CD133 + subgroup and CD133-subgroup would gradually start to change in apoptotic morphology.The growth inhibiting rate by CCK-8 measurement for 5-FU,DDP and VP-16 groups in CD133 + subgroup was significantly lower than that in CD133-subgroup.The data under different treatment respectively was,5-FU:(30.56 ± 1.99) ％-(88.60 ± 1.95) ％ vs (32.81 ± 2.67) ％-(95.73±2.12)％,P=0.045,cisplatin:(45.89 ±3.64)％-(81.20 ± 1.18)％ vs (50.21 ±3.22)％-(90.46±1.89)％,P=0.043,VP-16:(37.21 ±3.80)％-(78.49 ±3.22)％ vs (35.55 ±3.23)％-(89.32 ±-3.54) ％,P =0.048).After treatment of these three kind of anti-tumour drugs,the expression level of Bcl-2 mR-NA decreased significantly and the expression level of BAX mRNA increased significantly in both CD133 + subgroup and CD133-subgroup.However,these changing ranges of Bcl-2 mRNA and BAX mRNA were more obvious in CD133 + subgroup in comparison with those in CD133-subgroup.Conclusions In some degree,resistent potentiality of CD133 + cells to 5-FU,DDP and VP-16 has been identified,which may probably be due to the up-regulation of the expression of BAX and down-regulation of the expression of Bcl-2.

Transforming growth factor-β1 induces epithelial-to-mesenchymal transition and promotes abtaining of stemness characteristics in gastric cancer / 国际外科学杂志

Objective To investigate if TGF-β1 induces epithelial-mesenchymal transition (EMT) and promotes the obtaining of stemness characteristics in gastric cancer cell lines.Methods After KATO-Ⅲ cells were cultured with or without 5 ng/mL TGF-β1,the morphological change was observed and compared under phase-contrast microscopy.At the same time,the effect of TGF-β1 on the proliferation of KATO-Ⅲ cells was detected by CCK-8.On the other hand,the mRNA and protein' s expressions of EMT-related factors,ESC markers and TICs markers were analyzed by RT-PCR and Western blotting methods too.Results TGF-β1 induced morphological alterations from epithelial to mesenchymal cells.The proliferation of KATO-Ⅲ cells was inhibited after treated with TGF-β1 (P ＜ 0.05).After treated with TGF-β1,the relative mRNA expression levels of Snail (0.5219 ±0.0147) and N-cadherin(0.6640 ±0.0124) were higher than that in control group(0.2049 ±0.0214,P =0.004,0.2722 ± 0.0098,P =0.001),the relative protein expression levels of Snail (0.4769 ± 0.0234) and N-cadherin (0.5014 ± 0.0216) were higher than that in control group (0.2534 ± 0.0345,P =0.02,0.2026 ± 0.0268,P =0.009),while the relative E-cadherin mRNA and protein levels in TGF-β1 treated group (0.4701 ± 0.0215,0.1349 ± 0.0258) were lower than that in control group (0.6792 ± 0.0157,P =0.01 ; 0.6055 ± 0.0227,P =0.004),while the relative mRNA expressions of ESC markers such as Sox2,OCT4,Nanog in TGF-β1 treated group (0.594 ± 0.039、0.438 ± 0.033、0.489 ± 0.037) were higher than that in control group (0.143 ± 0.013,P =0.001,0.156 ± 0.025,P =0.001,0.325 ± 0.046,P =0.03),the relative mRNA expression levels of CD44 (0.437 ±0.037) and CD133(0.543 ±0.028) were higher than that in control group (0.247 ±0.024,P =0.000,0.139 ± 0.016,P =0.000),the relative protein expression levels of CD44 (0.429 ± 0.034) and CD133 (0.316 ±0.027) in TGF-β1 treated group were higher than that in control group (0.152 ± 0.014,P =0.000,0.110 ±0.010,P =0.000),cloning sphere-forming capacity was greatly enhanced after treated with TGF-β1 (P ＜ 0.01).Conclusion TGF-β1 can induce EMT in KATO-Ⅲ cells and promote the obtaining of stemness characteristics in gastric cancer cell lines.

Cancer stem cell markers as potential targets for epithelial cancers.

In recent years, the role of tumor-initiating cells (popularly known as cancer stem cells) in tumor development and availability of novel cancer stem cell/tumor initiating cell markers promises a new arena in understanding their role in developing novel targeted molecules. It is important to identify and understand the relevance of cancer stem cells (CSC)/tumor initiating cells (TIC) in tumor development and to design appropriate strategies for CSCs and TICs elimination, which is crucial to future cancer prevention and treatment. In this review, we attempt to define various potential markers of cancer stem cells and potential exploration as therapeutic targets for epithelial cancer prevention and treatment.

Origins and clinical implications of the tumor stem cell hypothesis / 肿瘤研究与临床

With the advent of the cancer stem cell hypothesis,the field of cancer research has experienced a revolution in how we think of and approach cancer. The discovery of "tumor-initiating cell" has offered an explanation for several long-standing conundrums on why tumors behave the way they do to treatment. Despite the great amount of research that has been done in order to understand the molecular aspects of tumors,the prognosis of tumors remains dismal. The slow progress in extending the survival of patients with malignant tumors is very likely due to poor understanding of the cell of origin in these tumors.This review article discusses the progress in our understanding of tumor-initiating cell as the cell of origin in cancers. We review the different proposed mechanisms of how tumor-initiating cell may originate,the molecular mechanisms of cancer initiation and progression, and finally the clinical implications of this research.