Dependence of Rydberg-atom-based sensor performance on different Rydberg atom populations in one atomic-vapor cell

The atomic-vapor cell is a vital component for Rydberg atomic microwave sensors,and impacts on overall capability of Rydberg sensors.However,the conventional analysis approach on effect of vapor-cell length contains two implicit assumptions,that is,the same atomic population density and buffer gas pressure,which make it unable to accurately capture actual response about effect of Rydberg-atom-based sensor performance on different Rydberg atom populations.Here,utilizing a stepped cesium atomic-vapor cell with five different dimensions at the same atomic population density and buffer gas pressure,the height and full width at half maximum of electromagnetically induced transparency(EIT)signal,and the sensitivity of the atomic superheterodyne sensor are comprehensively investigated under conditions of the same Rabi frequencies(saturated laser power).It is identified that EIT signal height is proportional to the cell length,full width at half maximum and sensitivity grow with the increment of cell length to a certain extent.Employing the coherent integration signal theory and atomic linear expansion coefficient method,theoretical analysis of the EIT height and sensitivity are further investigated.The results could shed new light on understanding and design of ultrahigh-sensitivity Rydberg atomic microwave sensors and find promising applications in quantum measurement,communication,and imaging.

Persistence of side population cells with high drug efflux capacity in pancreatic cancer

AIM: To investigate the persistence of side population (SP) cells in pancreatic cancer and their role and mechanism in the drug resistance. METHODS: The presentation of side population cells in pancreatic cancer cell line PANC-1 and its proportion change when cultured with Gemcitabine, was detected by Hoechst 33342 staining and FACS analysis. The expression of ABCB1 and ABCG2 was detected by real- time PCR in either SP cells or non-SP cells. RESULTS: SP cells do exist in PANC-1, with a median of 3.3% and a range of 2.1-8.7%. After cultured with Gemcitabine for 3 d, the proportion of SP cells increased significantly (3.8% ± 1.9%, 10.7% ± 3.7%, t = 4.616, P = 0.001 < 0.05). ABCB1 and ABCG2 expressed at higher concentrations in SP as compared with non-SP cells (ABCB1: 1.15 ± 0.72, 5.82 ± 1.16, t = 10.839, P = 0.000 < 0.05; ABCG2: 1.16 ± 0.75, 5.48 ± 0.94, t = 11.305, P = 0.000 < 0.05), which may contribute to the efflux of fluorescent staining and drug resistance. CONCLUSION: SP cells with inherently high resistance to chemotherapeutic agents do exist in pancreatic cancers, which may be candidate cancer stem cells contributing to the relapse of the tumor.

Side Population Cells in Human Gallbladder Cancer Cell Line GBC-SD Regulated by TGF-β-induced Epithelial-mesenchymal Transition

Mounting evidence has shown that side population （SP） cells are enriched for cancer stem cells （CSCs） responsible for cancer malignancy. In this study, SP technology was used to isolate a small subpopulation of SP cells in human gallbladder cancer cell line GBC-SD, and SP cells which had superior potential for proliferation in vitro and tumorigenesis in vivo were identified. Importantly, the abundance of GBC-SD SP cells was increased by a transforming growth factor-β （TGF-β）-induced epithelial-mesenchymal transition （EMT）, and this effect was accompanied with a strong up-regulation of ABCG2 mRNA expression, and a decreased sensitivity to mitoxantrone. SP cells were restored upon the removal of TGF-β and the reversion of the cells to an epithelial phenotype, and smad3-specific siRNA reduced SP abundance in response to TGF-β. In conclusion, TGF-β-induced EMT by smad-dependent signaling pathway promotes cancer development and anti-cancer drug resistant phenotype by augmenting the abundance of GBC-SD SP cells, and a better understanding of mechanisms involved in TGF-β-induced EMT may provide a novel strategy for preventing cancer progression.

Isolation and Identification of Cancer Stem-like Cells from Side Population of Human Prostate Cancer Cells

It has been widely verified by various sorting methods that cancer stem cells (CSCs) exist in different types of tumor cells or tissues.However,due to lack of specific stem cell surface markers,CSCs are very difficult to be separated from some cancer cells,which becomes the key barrier of functional studies of CSCs.The sorting method by side population cells (SP) lays a solid foundation for in-depth and comprehensive study of CSCs.To identify the existence of SP in prostate cancer cell lines,we applied flow cytometry sorting by SP to cultures of prostate cancer cell lines (TSU,LnCap,and PC-3),and the cancer stem-like characteristics of SP were verified through experiments in vitro and in vivo.The proportion of SP in TSU cells was calculated to be 1.60%±0.40% (±s),and that in PC-3 and LnCap cells was calculated to be 0.80%±0.05% and 0.60%±0.20%,respectively.The colony formation assay demonstrated that the colony formation rate of SP to non-SP sorted from TSU via flow cytometry was 0.495±0.038 to 0.177±0.029 in 500 cells,0.505±0.026 to 0.169±0.024 in 250 cells,and 0.088±0.016 to 0.043±0.012 in 125 cells respectively.In the in vivo experiments,tumors were observed in all the mice on the 10th day after injecting 50 000 cells subcutaneously in SP group,whereas when 5×106 cells were injected in non-SP group,tumors were developed in only 4 out of 8 mice until the 3rd week before the end of the experiment.Our results revealed that prostate cancer cells contain a small subset of cells,called SP,possessing much greater capacity of colony formation and tumorigenic potential than non-SP.These suggest that SP in prostate cancer cells may play a key role in the self-renewal and proliferation,and have the characteristics of cancer stem-like cells.Dissecting these features will provide a new understanding of the function of prostate CSCs in tumorigenicity and transformation.

Isolation of Side Population Cells and Detection of ABCG2 from SW480

Objective：Side population cells （SP cells） are a new type of stem cells. They mainly express ABCG2/BCRP1 and have the ability to eliminate DNA dye Hoechst33342. Many studies showed that side population cells were able of self-renewal, differentiation and carcinogenesis in cancers. Our investigation aimed at isolation of side population cells and ABCG2 positive subpopulation.from colon cancer cell line SW480 and identification of their characteristics of cancer stem cells. Methods： side population cells and non-side population cells of colon cancer cell line SW480 were isolated with DNA dye Hoechst33342 and their cell cycles were measured by flow cytometry. Expression of ABCG2 of SW480 was measured by immunohistochemistry and immunofluorescence, and its proportion was measured by flow cytometry. Results： SW480 contained 2.29% side population ceils. The fraction of side population ceils decreased greatly to 0.40% by treatment with verapamil. The fraction of side population cells in S-G2M cell cycle was 16.14%, which was much lower than the fraction （34.05%） of non-side population cells in S-G2M. In SW480, ABCG2 positive cells, which proportion was 9.66%, were small, circular or oval, lack of psuedopods, similar to poor differentiation. On the contrary, the ABCG2 negative cells were large, polygonal, with many psuedopods, similar to high differentiation. ConclusJon： our assay identified that side population cells did exist in SW480 and had a quiescence characteristic of stem cells. ABCG2 positive subpopulation occupied about 9.66% of SW480 and may have the ability to promote cell self-renewal and inhibit cell differentiation. Therefore, to isolate ABCG2 positive subpopulation from side population cells may be an alternative to study colorectal cancer stem cells.

Side population cells isolated from KATO Ⅲ human gastric cancer cell line have cancer stem cell-like characteristics

AIM: To investigate whether the side population (SP) cells possess cancer stem cell-like characteristics in vitro and the role of SP cells in tumorigenic process in gastric cancer. METHODS: We analyzed the presence of SP cells indifferent human gastric carcinoma cell lines, and then isolated and identified the SP cells from the KATO Ⅲ human gastric cancer cell line by flow cytometry. The clonogenic ability and self-renewal were evaluated by clone and sphere formation assays. The related genes were determined by reverse transcription polymerase chain reaction. To compare tumorigenic ability, SP and non-side population (NSP) cells from the KATO Ⅲ human gastric cancer cell line were subcutaneously injected into nude mice. RESULTS: SP cells from the total population accounted for 0.57% in KATO Ⅲ, 1.04% in Hs-746T, and 0.02% in AGS (CRL-1739). SP cells could grow clonally and have self-renewal capability in conditioned media. The expression of ABCG2, MDRI, Bmi-1 and Oct-4 was different between SP and NSP cells. However, there was no apparent difference between SP and NSP cells when they were injected into nude mice. CONCLUSION: SP cells have some cancer stem celllike characteristics in vitro and can be used for studying the tumorigenic process in gastric cancer.

Identification and Characterization of Side Population Cells in Human Lung Adenocarcinoma SPC-A1 Cells

Objective：There has been an increasing interest in recent years in the role of stem cells.With an extensive understanding of their biology,a major role for stem cells in the malignant process has been proposed and the existence of cancer stem cells（CSCs） has been confirmed in hematopoietic malignancies and solid organ malignancies including brain cancer,breast,prostate,colon,and pancreatic cancer.Lung cancer is the leading cause of cancer mortality in most large cities of China.It is possible that lung cancer contains cancer stem cells responsible for its malignancy.The aim of this study is to identify,characterize and enrich the CSC population that drives and maintains lung adenocarcinoma growth and metastasis.Methods：Side population（SP） cell analysis and sorting were applied on human lung adenocarcinoma cell line and an attempt to further enrich them by preliminary serum-free culture before fluorescence activated cell sorting（FACS） was done.Stem cell properties of SP cells were evaluated by their proliferative index,colony-forming efficiency,tumorigenic potential,bi-differentiation capacity and the expression of common stem cell surface markers.Results：Lung cancer cells could grow in a serum-free Medium（SFM） as non-adherent spheres similar to neurospheres or mammospheres.The proportion of SP cells in cell spheres was significantly higher than that in cells grown as monolayers.SP cells had a greater proliferative index,a higher colony-forming efficiency and a greater ability to form tumor in vivo.SP cells were both CCA positive and SP-C positive while non-SP cells were only SP-C positive.Flow cytometric analysis of cell phenotype showed that SP cells expressed CD133 and CD44,the common cell surface markers of cancer stem cells,while non-SP cells only expressed CD44.Conclusion：SP cells existed in human lung adenocarcinoma cell lines and they could be further enriched by preliminary serum-free culture before FACS sorting.SP cells possessed the properties of cancer stem cells.

Targeting BCRP/ABCG2 by RNA Interference Enhances the Chemotherapy Sensitivity of Human Colon Cancer Side Population Cells

Relapse and metastasis are frequent in colon cancer and may be linked to stem cell characteristics.This study isolated side population（SP） cells from a colon cancer cell line（Colo-320） and examined their self-renewal and differentiation abilities.Compared to non-SP（NSP） cells,SP colon cancer cells were more tumorigenic in vivo and exhibited more invasive characteristics and a greater ability to form colonies.Additionally,more cells were in G0/G1 phase and more highly expressed the multidrug resistance protein BCRP/ABCG2.We achieved enhanced chemotherapy sensitivity by transfecting SP cells with a hairpin-like,small interfering RNA（si RNA） eukaryotic expression plasmid targeting BCRP/ABCG2.

Isolation of side population cells from gallbladder carcinoma of human being and the expression of ABCG2 gene

Objective: To investigate whether the side population cells (SP cells) exist in human gallbladder carcinoma cell line and the differences of drug resistance gene ABCG2 expression in SP cells, non-SP cells and GBC-SD cell lines. Methods: Fluorescence activated cell sorter (FACS) was used to sort the SP and non-SP cells from GBC-SD cell line of gallbladder carcinoma of human being. Then, the sorting cells were cultured and detected the expression of ABCG2 gene among the SP cells, non-SP cells and GBC-SD cell lines by using reverse transcription polymerase chain reaction (RT-PCR), immunofluo-rescence chemistry, western blot and flow cytometry techniques. Results: A very small fraction cells (0.64 ± 0.08%) were iso-lated through FACS analysis which had the potency of stem cells and highly expressed ABCG2 gene (89.56 ± 3.86%). On the contrary, there were nearly no expression in non-SP cells (1.32 ± 0.49%) and lower expression in GBC-SD cell line (12.37 ± 1.61%). Conclusion: The side population cells that had the potency of stem cells existed in human gallbladder carcinoma cell line and over-expressed the drug resistance gene ABCG2. They may be play an important role in drug resistance of tumor.

Identification and analysis of a minority fraction in a U87 cell line Do side-population cells represent bona fide stem cell-like cancer cells?

BACKGROUND： Overwhelming evidence suggests that tumor bulks are comprised of differentiated tumor cells and cancer stem cells （CSCs）. The stem cell-like side-population （SP） cells account for a minor fraction of the total tumor cells, yet are apparently the cells capable of tumor initiation, growth, maintenance, and recurrence. OBJECTIVE： To identify potential stem cell-like cancer cells in a U87 human brain glioma cell line on the basis of dye efflux, clone formation, and multi-drug resistance capacity. DESIGN, TIME AND SETTING： The cellular and molecular biology experiment was performed at the Laboratory of Shanghai Institute of Hematology and Laboratory of Shanghai Institute of Endocrinology in Ruijin Hospital; in vivo contrast observational animal trial was performed at Experimental Animal Center, School of Medicine, Shanghai Jiao Tong University from June 2007 to May 2008. MATERIALS： The U87 cell line was provided by the Shanghai Institute of Cancer Research, Chinese Academy of Science; DMEM/F12 （1 ： 1） and fetal bovine serum were purchased from Gibco Invitrogen, USA; human recombinant basic fibroblast growth factors were purchased from BD Bioscience, USA; Hoechst 33342, Verapamil, and methyl thiazolyl tetrazolium were purchased from Sigma, USA; phycoerythrin-labeled anti-human-CD133 was purchased from Milteny Biotec, Germany; SYBR PrimeScriptTM RT-PCR kit was purchased from TaKaRa Biotechnology, Dalian, China. METHODS： Monolayer cultured cells were harvested by 0.25% Trypsin-EDTA and suspended at a 1 ×10^6/mL dilution in PBS containing 2% FBS, and were stained with Hoechst 33342 dye, either alone or in combination with Verapamil. Following fluorescence-activated cell sorting, SP and non-SP subsets were cultivated with serum-containing （DMEM plus 10% fetal bovine serum） or serum-free culture medium [DMEM/F12 （1： 1） ＋ 1× B27 supplement ＋ 10 ng/mL basic fibroblast growth factors ＋ 1× L-glutamine] to determine growth characteristics in vitro. Finally, single free U87 cells and subsets （SP or non-SP cells） were subcutaneously injected into the backs of 5-week-old nude mice for in vivo tumorigenicity. MAIN OUTCOME MEASURES： Cell morphology and clonogenicity were observed under inverted microscope; SP phenotype and fluorescent antibody labeling were analyzed by MoFIoTM flow cytometry; ABC transporter mRNA expression was evaluated by semi-quantitative real-time RT-PCR; efflux capacity for anti-neoplastic drugs from the U87 cell line and subsets was measured with the MTT assay, then detected by enzyme-linked immunosorbent assay at a wavelength of 490 nm; in vivo tumorigenicity in immunodeficient nude mice was evaluated by diameter size. RESULTS： During in vitro passages, human U87 cells maintained a stable SP fraction profile and exhibited the ability to form neurosphere-like clones. SP cell proliferation decreased compared with non-treated U87 cells. CD133 expression was reduced in the SP and non-SP cells. Freshly sorted SP fractions expressed higher levels of ABC drug transporter genes, and exhibited increased potential for cytotoxic drug resistance. The in vivo malignancy of U87 cells was largely dependent on non-SP cells in nude mice, and tumors that formed from the non-SP fraction developed faster and larger compared with tumors from the SP fraction. CONCLUSION： The SP cell component was a key factor that influenced mRNA expression and cytotoxic drug resistance. In particular, cancer stem cells or tumor-initiating cells were not exclusively enriched in the SP subset of the U87 cell line, and non-SP cells were even more tumorigenic.

Characterization of Side Cell Populations Obtained from Human Amnion Mesenchymal Cells

Human amnion mesenchymal cells （AMCs） contain muhipotent cells. To enrich such muhipotent stem cells, we applied to AMCs the new method for the isolation of side population （SP） cells used for the enrichment of muhipotent stem cells from many tissues. We succeeded in obtaining SP cells from AMCs （AMC-SP cells）. AMC-SP cells were found in 0.2 % of AMCs, irrespective of the length of pregnant period, ranging from 37 to 40 weeks. Cell cycle analyses suggested that AMC-SP cells belonged to a cell population that proliferated very slowly and/or was in a quiescent state in the amniotic membrane. Upon culturing, they proliferated with 40 to 80 cell doublings. However, they did not form colonies in a soft agarose culture, whereas HepG2 cells, representative human hepatoma cells formed many large colonies. These results suggest that AMC-SP cells that have considerable value for the use of regenerative medicine can be managed safely in vitro.

Atomic magnetometer with microfabricated vapor cells based on coherent population trapping

An atomic magnetometer based on coherent population trapping(CPT) resonances in microfabricated vapor cells is demonstrated. Fabricated by the micro-electro-mechanical-system(MEMS) technology, the cells are filled with Rb and Ne at a controlled pressure. An experimental apparatus is built for characterizing properties of microfabricated vapor cells via the CPT effects. The typical CPT linewidth is measured to be about 3 k Hz(1.46 k Hz with approximately zero laser intensity) for the rubidium D1 line at about 90℃. The effects of pressure, temperature and laser intensity on CPT linewidth are studied experimentally. A closed-loop atomic magnetometer is finally finished with a sensitivity of 210.5 p T/Hz1/2 at 1 Hz bandwidth. This work paves the way for developing an integrated chip-scale atomic magnetometer in the future.

Distinct Side Population Cell Subtypes Have Different Stemness Levels in Human Ovarian Cancer Cells

The stemness of different side population(SP)cell subtypes in ovarian cancer cells was studied,and the heterogeneity of ovarian cancer stem cells was analyzed.The cisplatin-resistant human serous ovarian cancer cell line C13 was stained with the bisbenzimide Hoechst 33342.A flow cytometry-based fluorescence-activated sorting method was used to obtain lower-SP(LSP)cells,upper-SP(USP)cells,and non-SP cells(NSP)based on their sensitivity to the staining time and Hoechst dye concentration.The sphere-forming capability,expression levels of stem cell markers,resistance to high concentrations of cisplatin,and subcutaneous tumorigenicity in NOD/SCID mice of the different cell subtypes were evaluated.The C13 cells contained SP cells with stemness characteristics,and the LSP cell subtype expressed higher levels of stem cell markers,had higher in vitro sphere-forming capability,higher cisplatin resistance and higher in vivo subcutaneous tumorigenesis than USP cells(P<0.05).NSP cells had no stemness.In conclusion,different subtypes of ovarian cancer SP cells have different stemness levels,and ovarian cancer stem cells may be heterogeneous.

Human papillomavirus in squamous cell carcinoma of esophagus in a high-risk population

AIM: To investigate the relation of human papillomavirus (HPV) and esophageal squamous cell carcinoma (ESCC) in Iranian patients as compared to normal controls. METHODS: Using MY09/MY11 consensus primers, we compared the prevalence of a HPV L1 gene in tumor tissues from 38 ESCC cases and biopsied tissues from 38 endoscopically normal Iranian individuals. We also compared the presence of HPV16 and HPVA18 in the same samples using type-specific E6/E7 primers. RESULTS: Fourteen (36.8%) of the 38 ESCC samples but only 5 (13.2%) of the 38 control samples were positive for the HPV L1 gene (P= 0.02). Five (13.2%) of the ESCC samples but none of the control samples were positive for the HPV16 E6/E7 gene (P= 0.05). Three (7.9%) of the ESCC samples and 5 (13.2%) of the control samples were positive for the HPV18 E6/E7 gene (P= 0.71). CONCLUSION: Our data are consistent with HPV DNA studies conducted in other high-risk areas for ESCC. HPV should be considered as a potential factor contributing to the high incidence of ESCC in Iran and other high-incidence areas of the world.

Characterizing passive coherent population trapping resonance in a cesium vapor cell filled with neon buffer gas

We present a pair of phase-locked lasers with a 9.2-GHz frequency difference through the injection locking of a master laser to the RF-modulation sideband of a slave diode laser. Using this laser system, a coherent population trapping （CPT） signal with a typical linewidth of ～ 182 Hz is obtained in a cesium vapor cell filled with 30 Torr （4kPa） of neon as the buffer gas. We investigate the influence of the partial pressure of the neon buffer gas on the CPT linewidth, amplitude, and frequency shift. The results may offer some references for CPT atomic clocks and CPT atomic magnetometers.

Central Upwind Scheme for Solving Multivariate Cell Population Balance Models

Microbial cultures are comprised of heterogeneous cells that differ according to their size and intracellular concentrations of DNA, proteins and other constituents. Because of the included level of details, multi-variable cell population balance models (PBMs) offer the most general way to describe the complicated phenomena associated with cell growth, substrate consumption and product formation. For that reason, solving and understanding of such models are essential to predict and control cell growth in the processes of biotechnological interest. Such models typically consist of a partial integro-differential equation for describing cell growth and an ordinary integro-differential equation for representing substrate consumption. However, the involved mathematical complexities make their numerical solutions challenging for the given numerical scheme. In this article, the central upwind scheme is applied to solve the single-variate and bivariate cell population balance models considering equal and unequal partitioning of cellular materials. The validity of the developed algorithms is verified through several case studies. It was found that the suggested scheme is more reliable and effective.

FSPAM:A Feature Construction Method to Identifying Cell Populations in ScRNA-seq Data

The emergence of single-cell RNA-sequencing(scRNA-seq)technology has introduced new information about the structure of cells,diseases,and their associated biological factors.One of the main uses of scRNA-seq is identifying cell populations,which sometimes leads to the detection of rare cell populations.However,the new method is still in its infancy and with its advantages comes computational challenges that are just beginning to address.An important tool in the analysis is dimensionality reduction,which transforms high dimensional data into a meaningful reduced subspace.The technique allows noise removal,visualization and compression of high-dimensional data.This paper presents a new dimensionality reduction approach where,during an unsupervised multistage process,a feature set including high valuable markers is created which can facilitate the isolation of cell populations.Our proposed method,called fusion of the Spearman and Pearson affinity matrices(FSPAM),is based on a graph-based Gaussian kernel.Use of the graph theory can be effective to overcome the challenge of the nonlinear relations between cellular markers in scRNA-seq data.Furthermore,with a proper fusion of the Pearson and Spearman correlation coefficient criteria,it extracts a set of the most important features in a new space.In fact,the FSPAM aggregates the various aspects of cell-to-cell similarity derived from the Pearson and Spearman metrics,and reveals new aspects of cell-to-cell similarity,which can be used to extract new features.The results of the identification of cell populations via k-means++clustering method based on the features extracted from the FSPAM and different datasets of scRNA-seq suggested that the proposed method,regardless of the characteristics that govern each dataset,enjoys greater accuracy and better quality compared to previous methods.

Tayloring cell populations for neurodegenerative diseases

Neurological disorders are increasing in prevalence world- wide, and interest in stem cell therapies for these amictions has increased over the past two decades. While many neu- rological injuries are too devastating for the repair capabil- ities of endogenous neural stem cells （NSCs） an alternative is to harvest stem cells from a donor and grow them in vitro, to be used later as a donor source for transplantation. Many research groups have already done this, first using animal models and now using clinical trial participants. Despite the regular flow of publications about cell replace- ment therapies for central nervous system （CNS） disorders, there is still a scarcity of clinically-relevant reports of effi- cacy. The capability of donor cells to undergo ample site-di- rected differentiation and functional integration seems to be lacking （Andressen, 2013）. So, while stem cells do have properties that are suited for repair of the injured CNS, a primary remaining question is how these cells can best be grafted to produce long-term functional benefit to the host environment. Moreover, among the challenges in neural cell transplantation is controlling the ultimate characteris- tics of grafted cells, pertaining to their survival, phenotypes and performance.

Sox2 enhances the tumorigenicity and chemoresistance of cancer stem-like cells derived from gastric cancer

Gastric cancer stem-like cells（GCSCs） have been identified to possess the ability of self-renewal and tumor initi-ation.However,the mechanisms involved remain largely unknown.Here,we isolated and characterized the GCSCs by side population（SP） sorting procedure and cultured sphere cells（SC） from human gastric cancer cell lines SGC-7901,BGC-823,MGC-803,HGC-27 and MKN-28.The sorting and culture assay revealed that SP cells proliferated in an asymmetric division manner.In addition,SP cells exhibited a higher potential of spheroid colony formation and greater drug resistance than non-SP cells（NSP）.Moreover,the SC were found with enhanced capabilities of drug resistance in vitro and tumorigenicity in vivo.Sox2 mRNA and protein was highly and significantly overex-pressed in the SP cells and SC.Importantly,downregulation of Sox2 with siRNA obviously reduced spheroid colony formation and doxorubicin efflux,as well as increased apoptosis rate in sphere cells in vitro and suppressed tumori-genicity in vivo.These results suggest that both SP cells and cultured SC enrich with GCSCs and that Sox2 plays a pivotal role in sustaining stem cell properties and might be a potential target for gastric cancer therapy.