Targeting STAT3 with SH-4-54 suppresses stemness and chemoresistance in cancer stem-like cells derived from colorectal cancer

BACKGROUND Over the years,the numbers of treatment options for colorectal cancer(CRC)have increased,leading to notable improvements in the overall survival of CRC patients.Although therapy may initially yield positive results,the development of drug resistance can result in treatment failure and cancer recurrence.This resistance is often attributed to the presence of cancer stem cells(CSCs).These CSCs not only contribute to therapeutic resistance but also play crucial roles in the initiation and development of tumor metastasis.AIM To investigate the antitumor effects of SH-4-54,which are mediated by targeting CSCs relative to treatment outcomes.METHODS CSCs were enriched by culturing CRC cells in serum-free medium.Hallmarks of stemness and IL-6/JAK2/STAT3 signaling were detected by Western blotting.Indicators of CSC malignancy,including proliferation,invasion,and tumor formation,were measured.RESULTS In this study,we employed SH-4-54,which exhibits anticancer activity in solid tumors through targeting the SH2 domain of both the signal transducer and activator of transcription(STAT)3 and the STAT5,and evaluated its effects on stemness and chemoresistance in colorectal CSCs.As expected,SH-4-54 treatment inhibited the phosphorylation of STAT3(p-STAT3)and decreased the percentage of ALDH1A1-positive CRC cells.The addition of SH-4-54 dissociated colorectal spheroids and decreased the expression of stemness markers,including ALDH1A1,CD44 and Nanog.SH-4-54 treatment decreased IL-6/JAK2/STAT3 signaling by inhibiting p-STAT3 and thus inhibited spheroid formation by SW480 and LoVo cells.Moreover,SH-4-54 treatment inhibited indicators of malignancy,including cell proliferation,invasion,and tumor formation,in CSCs in vitro and in vivo.Notably,SH-4-54 treatment significantly increased chemosensitivity to oxaplatin.CONCLUSION Taken together,these results indicate that SH-4-54 is a promising molecule that exerts antitumor effects on colorectal CSCs by inhibiting STAT3 signaling.

VX-509 attenuates the stemness characteristics of colorectal cancer stem-like cells by regulating the epithelial-mesenchymal transition through Nodal/Smad2/3 signaling

BACKGROUND Colorectal cancer stem cells(CCSCs)are heterogeneous cells that can self-renew and undergo multidirectional differentiation in colorectal cancer(CRC)patients.CCSCs are generally accepted to be important sources of CRC and are responsible for the progression,metastasis,and therapeutic resistance of CRC.Therefore,targeting this specific subpopulation has been recognized as a promising strategy for overcoming CRC.AIM To investigate the effect of VX-509 on CCSCs and elucidate the underlying mechanism.METHODS CCSCs were enriched from CRC cell lines by in conditioned serum-free medium.Western blot,Aldefluor,transwell and tumorigenesis assays were performed to verify the phenotypic characteristics of the CCSCs.The anticancer efficacy of VX-509 was assessed in HCT116 CCSCs and HT29 CCSCs by performing cell viability analysis,colony formation,sphere formation,flow cytometry,and western blotting assessments in vitro and tumor growth,immunohistochemistry and immunofluorescence assessments in vivo.RESULTS Compared with parental cells,sphere cells derived from HCT116 and HT29 cells presented increased expression of stem cell transcription factors and stem cell markers and were more potent at promoting migration and tumori-genesis,demonstrating that the CRC sphere cells displayed CSC features.VX-509 inhibited the tumor malignant biological behavior of CRC-stem-like cells,as indicated by their proliferation,migration and clonality in vitro,and suppressed the tumor of CCSC-derived xenograft tumors in vivo.Besides,VX-509 suppressed the CSC character-istics of CRC-stem-like cells and inhibited the progression of epithelial-mesenchymal transition(EMT)signaling in vitro.Nodal was identified as the regulatory factor of VX-509 on CRC stem-like cells through analyses of differen-tially expressed genes and CSC-related database information.VX-509 markedly downregulated the expression of Nodal and its downstream phosphorylated Smad2/3 to inhibit EMT progression.Moreover,VX-509 reversed the dedifferentiation of CCSCs and inhibited the progression of EMT induced by Nodal overexpression.CONCLUSION VX-509 prevents the EMT process in CCSCs by inhibiting the transcription and protein expression of Nodal,and inhibits the dedifferentiated self-renewal of CCSCs.

N6-methyladenosine-modified long non-coding RNA KIF9-AS1 promotes stemness and sorafenib resistance in hepatocellular carcinoma by upregulating SHOX2 expression

BACKGROUND Hepatocellular carcinoma(HCC)is a prevalent and aggressive tumor.Sorafenib is the first-line treatment for patients with advanced HCC,but resistance to sorafenib has become a significant challenge in this therapy.Cancer stem cells play a crucial role in sorafenib resistance in HCC.Our previous study revealed that the long non-coding RNA(lncRNA)KIF9-AS1 is an oncogenic gene in HCC.However,the role of KIF9-AS1 in drug resistance and cancer stemness in HCC remains unclear.Herein,we aimed to investigate the function and mechanism of the lncRNA KIF9-AS1 in cancer stemness and drug resistance in HCC.AIM To describe the role of the lncRNA KIF9-AS1 in cancer stemness and drug resistance in HCC and elucidate the underlying mechanism.METHODS Tumor tissue and adjacent non-cancerous tissue samples were collected from HCC patients.Sphere formation was quantified via a tumor sphere assay.Cell viability,proliferation,and apoptosis were evaluated via Cell Counting Kit-8,flow cytometry,and colony formation assays,respectively.The interactions between the lncRNA KIF9-AS1 and its downstream targets were confirmed via RNA immunoprecipitation and coimmunoprecipitation.The tumorigenic role of KIF9-AS1 was validated in a mouse model.RESULTS Compared with that in normal controls,the expression of the lncRNA KIF9-AS1 was upregulated in HCC tissues.Knockdown of KIF9-AS1 inhibited stemness and attenuated sorafenib resistance in HCC cells.Mechanistically,N6-methyladenosine modification mediated by methyltransferase-like 3/insulin-like growth factor 2 mRNA-binding protein 1 stabilized and increased the expression of KIF9-AS1.Additionally,KIF9-AS1 increased the stability and expression of short stature homeobox 2 by promoting ubiquitin-specific peptidase 1-induced deubiquitination.Furthermore,depletion of KIF9-AS1 alleviated sorafenib resistance in a xenograft mouse model of HCC.CONCLUSION The N6-methyladenosine-modified lncRNA KIF9-AS1 promoted stemness and sorafenib resistance in HCC by upregulating short stature homeobox 2 expression.

Ubiquitin-specific protease 21 promotes tumorigenicity and stemness of colorectal cancer by deubiquitinating and stabilizing ZEB1

BACKGROUND Colorectal cancer(CRC)is one very usual tumor together with higher death rate.Ubiquitin-specific protease 21(USP21)has been confirmed to take part into the regulation of CRC progression through serving as a facilitator.Interestingly,the promotive function of USP21 has also discovered in the progression of CRC.ZEB1 has illustrated to be modulated by USP7,USP22 and USP51 in cancers.However,the regulatory functions of USP21 on ZEB1 in CRC progression need more invest-igations.AIM To investigate the relationship between USP21 and ZEB1 in CRC progression.METHODS The mRNA and protein expressions were assessed through RT-qPCR,western blot and IHC assay.The interaction between USP21 and ZEB1 was evaluated through Co-IP and GST pull down assays.The cell proliferation was detected through colony formation assay.The cell migration and invasion abilities were determined through Transwell assay.The stemness was tested through sphere formation assay.The tumor growth was evaluated through in vivo mice assay.RESULTS In this work,USP21 and ZEB1 exhibited higher expression in CRC,and resulted into poor prognosis.Moreover,the interaction between USP21 and ZEB1 was further investigated.It was demonstrated that USP21 contributed to the stability of ZEB1 through modulating ubiquitination level.In addition,USP21 streng-thened cell proliferation,migration and stemness through regulating ZEB1.At last,through in vivo assays,it was illustrated that USP21/ZEB1 axis aggravated tumor growth.CONCLUSION For the first time,these above findings manifested that USP21 promoted tumorigenicity and stemness of CRC by deubiquitinating and stabilizing ZEB1.This discovery suggested that USP21/ZEB1 axis may provide novel sights for the treatment of CRC.

Prostaglandin D2 regulation of autophagy affects stemness of gastric cancer stem cells

Objective:To explore the effect and mechanism of prostaglandins D2(PGD2)on the stemness of gastric cancer stem cells(GCSCs).Methods:7901-GCSCs were enriched by serum-free culture method;then the positivity rate of CD44,a stemness marker,was detected by flow cytometry in serum-free cultured 7901-GCSCs;the sphere-forming ability was detected by the sphere-forming assay after stimulation with different concentrations of PGD2(2.5,5,10)μg/mL,and the expression of stemness-related indicators(OCT4,CD44)and autophagyrelated proteins(LC3,Beclin-1)after PGD2 stimulation was detected by the western blot assay in different concentrations.The expression of stemness-related indexes(OCT4,CD44)and autophagy-related proteins(LC3,Beclin-1)were detected by Western blot assay after stimulation with different concentrations of PGD2.The expression of autophagy-related proteins after stimulation with different concentrations of CQ(2.5,5,10)μM was detected by Western blot experiment.The protein expression of autophagy-related proteins(LC3,Beclin-1)and stemness-related indexes(OCT4,CD44)was detected by Western blot experiment after PGD2 as well as PGD2+CQ treatment.Results:Flow cytometry results showed that the expression of CD44 positivity was increased in serum-free cultured 7901-GCSCs compared with gastric cancer cells SGC-7901(P<0.05),which fulfilled the needs of subsequent experiments.The results of stem cell spheroid formation assay showed that the spheroid formation ability of 7901-GCSCs in the PGD2 group was significantly weakened compared with that of the DMSO group(P<0.05).Western blot results showed that the protein expression of stemness-related indexes(OCT4,CD44)was down-regulated in the 7901-GCSCs in the PGD2 group compared with that of the DMSO group(P<0.05),and the expression of autophagy-related proteins(LC3,Beclin-1)expression increased(P<0.05).Compared with the DMSO group,the expression of autophagy-related proteins(LC3,Beclin-1)was decreased in the CQ group(P<0.05).Western blot results also showed that the expression of cellular autophagy-related proteins and stemness-related indexes in the PGD2+CQ group was not significantly changed compared with that of the DMSO group(ns:the difference was not significant),suggesting that the CQ could block the effect of PGD2 on the expression of stemness markers in 7901-GCSCs.7901-GCSCs stemness inhibition.Conclusion:PGD2 may affect the stemness of 7901-GCSCs by regulating autophagy.

Oleanolic acid inhibits colon cancer cell stemness and reverses chemoresistance by suppressing JAK2/STAT3 signaling pathway

Background:Oleanolic acid(OA),a pentacyclic triterpenoid exhibiting specific anti-cancer properties and highly effective antioxidant activity,was isolated from traditional Chinese medicinal herbs.Conversely,the OA that impacts colon cancer(CC)cells and its underlying mechanisms remain poorly understood.Methods:The cytotoxic effect of OA alone or OA-5-Fluorouracil(5-FU)combination on normal and CC cells was analyzed by methyl thiazolyl diphenyl-tetrazolium bromide(MTT).Then,the impact of OA on CC cell lines(LoVo and HT-29)proliferation and stemness were measured using colon formation and tumorsphere formation assays.Octamer-binding transcription factor 4(Oct4),Prominin-1(CD133),Nanog,and transcription factor SOX-2(SOX2)are cell stemness-related indicators whose expression was assessed usingfluorescence qPCR assay,Western blotting,and immunohistochemistry.The effect of OA on the proliferative potency of CC cells was evaluated using an in vivo model.Results:The stem-like characteristics and clone production of colon cancer cells were markedly reduced by OA alone or in combination with OA-5-FU.Moreover,OA increases the susceptibility of CC cells to 5-FU by blocking the cell stemness-related markers(CD133,Nanog,SOX2,and Oct4)expression levels both in vitro and in vivo,as well as by inactivating the activator of transcription 3(STAT3 signaling)and Janus kinase 2/signal transducer(JAK2).Conclusion:Thesefindings imply that oleanolic acid,both in vitro and in vivo,suppresses the JAK2/STAT3 pathway,which in turn reverses chemoresistance and decreases colon cancer cell stemness.Therefore,by reducing the recommended amount of 5-FU,this strategy may improve chemotherapeutic effectiveness and minimize undesired side effects.

Research Progress of Breast Cancer Stem Cell Stemness and Breast Cancer Recurrence

Currently, breast cancer is the most common malignant tumour in Chinese women with a high incidence rate, and recurrence and metastasis are the main reasons affecting survival. Breast Cancer Stem Cells (BCSCs) are stem cells capable of continuous regeneration in vivo with strong self-renewal ability and multidirectional differentiation potential, which are highly tumourigenic and insensitive to radiotherapy and chemotherapy, and are highly susceptible to breast cancer recurrence. Therefore, exploring the stemness of BCSCs and their mechanism associated with recurrence is important for developing new therapeutic strategies, improving therapeutic efficacy, and improving patient prognosis.

Knockdown of circular RNA (CircRNA)_001896 inhibits cervical cancer proliferation and stemness in vivo and in vitro

Objective:Previous studies indicated that aberrant circular RNA(circRNA)expression affects gene expression regulatory networks,leading to the aberrant activation of tumor pathways and promoting tumor cell growth.However,the expression,clinical significance,and effects on cell propagation,invasion,and dissemination of circRNA_001896 in cervical cancer(CC)tissues remain unclear.Methods:The Gene Expression Omnibus(GEO)datasets(GSE113696 and GSE102686)were used to examine differential circRNA expression in CC and adjacent tissues.The expression of circRNA_001896 was detected in 72 CC patients usingfluorescence quantitative PCR.Correlation analysis with clinical pathological features was performed through COX multivariate and univariate analysis.The effect of circRNA_001896 downregulation on CC cell propagation was examined using the cell counting kit-8(CCK-8)test,clonogenic,3D sphere formation,and in vivo tumorigenesis assays.Results:Intersection of the GSE113696 and GSE102686 datasets revealed an increased expression of four circRNAs,including circRNA_001896,in CC tissues.Fluorescence quantitative PCR confirmed circRNA_001896 as a circular RNA.High expression of circRNA_001896 was considerably associated with lymph node metastasis,International Federation of Gynecologists and Obstetricians(FIGO)stage,tumor diameter,and survival period in CC patients.Proportional hazards model(COX)univariate and multivariate analyses revealed that circRNA_001896 expressions are a distinct risk factor affecting CC patients’prognosis.Cellular functional experiments showed that downregulating circRNA_001896 substantially suppressed CC cell growth,colony formation,and 3D sphere-forming ability.In vivo,tumorigenesis analysis in nude mice demonstrated that downregulating circRNA_001896 remarkably reduced the in vivo proliferation capacity of CC cells.Conclusion:CircRNA_001896 is highly expressed in CC tissues and is substantially related to lymph node metastasis,FIGO stage,tumor size,and survival period in patients.Moreover,downregulating circRNA_001896 significantly inhibits both in vivo and in vitro propagation of CC cells.Therefore,circRNA_001896 might be used as a biomarker for targeted therapy in cervical cancer.

UBE2T mediates the stemness properties of breast cancer cells through the mTOR signaling pathway

Objectives:This study aimed to reveal the role and possible mechanism of the ubiquitin-conjugating enzyme 2T(UBE2T)in the biological activities of breast cancer stem cells(BCSCs).Methods:The specific protein and gene expression were quantified by Western blotting and quantitative real-time polymerase chain reaction,the proportion of BCSCs was examined by flow cytometry,and the self-renewal and proliferation of BCSCs were verified by serial sphere formation and soft agar.Results:Increasing expression of UBE2T was drastically found in breast cancer than that in adjacent tissues.Furthermore,UBE2T overexpression significantly increased the proportion of BCSCs in breast cancer cells and promoted their self-renewal and proliferation.Silent UBE2T exhibited the opposite functions.UBE2T increased the levels of the mammalian target of rapamycin and the phosphorylated mammalian target of rapamycin.Mammalian target of rapamycin(mTOR)inhibitor rapamycin inhibited the function of UBE2T in BCSCs.Conclusion:UBE2T plays a role in BCSCs through mTOR pathway and may suggest a novel therapeutic strategy for breast cancer.

Multifaceted p21 in carcinogenesis,stemness of tumor and tumor therapy

Cancer cells possess metabolic properties that are different from those of benign cells.p21,encoded by CDKN1A gene,also named p21Cip1/WAF1,was first identified as a cyclin-dependent kinase regulator that suppresses cell cycle G1/S phase and retinoblastoma protein phosphorylation.CDKN1A(p21)acts as the downstream target gene of TP53(p53),and its expression is induced by wild-type p53 and it is not associated with mutant p53.p21 has been characterized as a vital regulator that involves multiple cell functions,including G1/S cell cycle progression,cell growth,DNA damage,and cell stemness.In 1994,p21 was found as a tumor suppressor in brain,lung and colon cancer by targeting p53 and was associated with tumorigenesis and metastasis.Notably,p21 plays a significant role in tumor development through p53-dependent and p53-independent pathways.In addition,expression of p21 is closely related to the resting state or terminal differentiation of cells.p21 is also associated with cancer stem cells and acts as a biomarker for such cells.In cancer therapy,given the importance of p21 in regulating the G1/S and G2 check points,it is not surprising that p21 is implicated in response to many cancer treatments and p21 promotes the effect of oncolytic virotherapy.

Special AT-rich sequence-binding protein 2 acts as a negative regulator of stemness in colorectal cancer cells

AIM To find the mechanisms by which special AT-rich sequence-binding protein 2(SATB2) influences colorectal cancer(CRC) metastasis.METHODS Cell growth assay, colony-forming assay, cell adhesion assay and cell migration assay were used to evaluate the biological characteristics of CRC cells with gain or loss of SATB2. Sphere formation assay was used to detect the self-renewal ability of CRC cells. The m RNA expression of stem cell markers in CRC cells with upregulated or downregulated SATB2 expression was detected by quantitative real-time polymerase chain reaction. Chromatin immunoprecipitation(Ch IP) was used to verify the binding loci of SATB2 on genomic sequences of stem cell markers. The Cancer Genome Atlas(TCGA) database and our clinical samples wereanalyzed to find the correlation between SATB2 and some key stem cell markers.RESULTS Downregulation of SATB2 led to an aggressive phenotype in SW480 and DLD-1 cells, which was characterized by increased migration and invasion abilities. Overexpression of SATB2 suppressed the migration and invasion abilities in SW480 and SW620 cells. Using sequential sphere formation assay to detect the selfrenewal abilities of CRC cells, we found more secondary sphere formation but not primary sphere formation in SW480 and DLD-1 cells after SATB2 expression was knocked down. Moreover, most markers for stem cells such as CD133, CD44, AXIN2, MEIS2 and NANOG were increased in cells with SATB2 knockdown and decreased in cells with SATB2 overexpression. Ch IP assay showed that SATB2 bound to regulatory elements of CD133, CD44, MEIS2 and AXIN2 genes. Using TCGA database and our clinical samples, we found that SATB2 was correlated with some key stem cell markers including CD44 and CD24 in clinical tissues of CRC patients.CONCLUSION SATB2 can directly bind to the regulatory elements in the genetic loci of several stem cell markers and consequently inhibit the progression of CRC by negatively regulating stemness of CRC cells.

road to stemness in hepatocellular carcinoma

Carcinogenic process has been proposed to relay on the capacity to induce local tissue damage and proliferative repair. Liver has a great regeneration capacity and currently, most studies point towards the dominant role of hepatocytes in regeneration at all levels of liver damage. The most frequent liver cancer is hepatocellular carcinoma(HCC). Historical findings originally led to the idea that the cell of origin of HCC might be a progenitor cell. However, current linage tracing studies put the progenitor hypothesis of HCC origin into question. In agreement with their dominant role in liver regeneration, mature hepatocytes are emerging as the cell of origin of HCC, although, the specific hepatocyte subpopulation of origin is yet to be determined. The relationship between the cancer cell of origin(CCO) and cancer-propagating cells, known as hepatic cancer stem cell(HCSC) is unknown. It has been challenging to identify the definitive phenotypic marker of HCSC, probably due to the existence of different cancer stem cells(CSC) subpopulations with different functions within HCC. There is a dynamic interconversion among different CSCs, and between CSC and non-CSCs. Because of that, CSC-state is currently defined as a description of a highly adaptable and dynamic intrinsic property of tumor cells, instead of a static subpopulation of a tumor. Altered conditions could trigger the gain of stemness, some of them include: EMT-MET, epigenetics, microenvironment and selective stimulus such as chemotherapy. This CSC heterogeneity and dynamism makes them out reach from therapeutic protocols directed to a single target. A further avenue of research in this line will be to uncover mechanisms that trigger this interconversion of cell populations within tumors and target it.

N^(6)-methyladenosine modification of CENPK mRNA by ZC3H13 promotes cervical cancer stemness and chemoresistance

Background:Stemness and chemoresistance contribute to cervical cancer recurrence and metastasis.In the current study,we determined the relevant players and role of N^(6)-methyladenine(m^(6)A)RNA methylation in cervical cancer progression.Methods:The roles of m^(6)A RNA methylation and centromere protein K(CENPK)in cervical cancer were analyzed using bioinformatics analysis.Methylated RNA immunoprecipitation was adopted to detect m^(6)A modification of CENPK mRNA.Human cervical cancer clinical samples,cell lines,and xenografts were used for analyzing gene expression and function.Immunofluorescence staining and the tumorsphere formation,clonogenic,MTT,and EdU assays were performed to determine cell stemness,chemoresistance,migration,invasion,and proliferation in HeLa and SiHa cells,respectively.Western blot analysis,co-immunoprecipitation,chromatin immunoprecipitation,and luciferase reporter,cycloheximide chase,and cell fractionation assays were performed to elucidate the underlying mechanism.Results:Bioinformatics analysis of public cancer datasets revealed firm links between m^(6)A modification patterns and cervical cancer prognosis,especially through ZC3H13-mediated m^(6)A modification of CENPK mRNA.CENPK expression was elevated in cervical cancer,associated with cancer recurrence,and independently predicts poor patient prognosis[hazard ratio=1.413,95%confidence interval=1.078−1.853,P=0.012].Silencing of CENPK prolonged the overall survival time of cervical cancer-bearing mice and improved the response of cervical cancer tumors to chemotherapy in vivo(P<0.001).We also showed that CENPK was directly bound to SOX6 and disrupted the interactions of CENPK withβ-catenin,which promotedβ-catenin expression and nuclear translocation,facilitated p53 ubiquitination,and led to activation of Wnt/β-catenin signaling,but suppression of the p53 pathway.This dysregulation ultimately enhanced the tumorigenic pathways required for cell stemness,DNA damage repair pathways necessary for cisplatin/carboplatin resistance,epithelial-mesenchymal transition involved in metastasis,and DNA replication that drove tumor cell proliferation.Conclusions:CENPK was shown to have an oncogenic role in cervical cancer and can thus serve as a prognostic indicator and novel target for cervical cancer treatment.

Linking stemness with colorectal cancer initiation, progression, and therapy

The discovery of cancer stem cells caused a paradigm shift in the concepts of origin and development of colorectal cancer. Several unresolved questions remain in this field though. Are colorectal cancer stem cells the cause or an effect of the disease? How do cancer stem cells assist in colorectal tumor dissemination to distant organs? What are the molecular or environmental factors affecting the roles of these cells in colorectal cancer? Through this review, we investigate the key findings until now and attempt to elucidate the origins, physical properties, microenvironmental niches, as well as the molecular signaling network that support the existence, self-renewal, plasticity, quiescence, and the overall maintenance of cancer stem cells in colorectal cancer. Increasing data show that the cancer stem cells play a crucial role not only in the establishment of the primary colorectal tumor but also in the distant spread of the disease. Hence, we will also look at the mechanisms adopted by cancer stem cells to influence the development of metastasis and evade therapeutic targeting and its role in the overall disease prognosis. Finally, we will illustrate the importance of understanding the biology of these cells to develop improved clinical strategies to tackle colorectal cancer.

SOX transcription factors and glioma stem cells:Choosing between stemness and differentiation

Glioblastoma(GBM)is the most common,most aggressive and deadliest brain tumor.Recently,remarkable progress has been made towards understanding the cellular and molecular biology of gliomas.GBM tumor initiation,progression and relapse as well as resistance to treatments are associated with glioma stem cells(GSCs).GSCs exhibit a high proliferation rate and self-renewal capacity and the ability to differentiate into diverse cell types,generating a range of distinct cell types within the tumor,leading to cellular heterogeneity.GBM tumors may contain different subsets of GSCs,and some of them may adopt a quiescent state that protects them against chemotherapy and radiotherapy.GSCs enriched in recurrent gliomas acquire more aggressive and therapy-resistant properties,making them more malignant,able to rapidly spread.The impact of SOX transcription factors(TFs)on brain tumors has been extensively studied in the last decade.Almost all SOX genes are expressed in GBM,and their expression levels are associated with patient prognosis and survival.Numerous SOX TFs are involved in the maintenance of the stemness of GSCs or play a role in the initiation of GSC differentiation.The fine-tuning of SOX gene expression levels controls the balance between cell stemness and differentiation.Therefore,innovative therapies targeting SOX TFs are emerging as promising tools for combatting GBM.Combatting GBM has been a demanding and challenging goal for decades.The current therapeutic strategies have not yet provided a cure for GBM and have only resulted in a slight improvement in patient survival.Novel approaches will require the fine adjustment of multimodal therapeutic strategies that simultaneously target numerous hallmarks of cancer cells to win the battle against GBM.

A novel nine gene signature integrates stemness characteristics associated with prognosis in hepatocellular carcinoma

Cancer stem cells(CSCs)are heterogeneous with self-renewal and differentiation ability.The mRNA expression-based stemness index(mRNAsi)described the similarity between tumor cells and CSCs,which is positively associated with the poor prognosis of cancer patients.However,the key prognostic genes related to mRNAsi in hepatocellular carcinoma(HCC)remains unclear.A 9-gene signature related to mRNAsi and HCC prognosis including PSMG3,SNRPD1,DTYMK,PIGU,NME1,TXNL4A,IPO4,PES1,and REXO4 was obtained.High expression of this signature indicates poor prognosis of HCC.PIGU was an independent prognostic factor of HCC,which was significantly associated with progression of HCC.Among them,DTYMK and NME1 enriched in pyrimidine metabolism,SNRPD1 and TXNL4A enriched in spliceosome and PIGU enriched in glycosyl phosphatidylinositol(GPI)-anchor biosynthesis pathways.High levels of IPO4,NME1,PES1,PIGU and SNRPD1 were closely associated with metastasis of HCC,and low levels of IPO4,PIGU and REOX4 were significantly associated with sorafenib resistance of HCC.High expression of the 9-gene signature was negatively correlated with the stromal cell infiltration,and positively correlated with specific immune subtypes-related to angiogenesis,M1/M2 macrophage polarization,and M2 response.The 9-gene signature was negatively correlated with the stroma,and SNRPD1 and TXNL4 were positively correlated with immune infiltrate.NME1 was negatively correlated with tumor purity.Therefore,a 9-gene signature related to mRNAsi and poor prognosis in HCC were identified,which can be used as biomarkers for the diagnosis of HCC and functional mechanism exploration of CSCs in HCC.These genes such as IPO4 and PIGU might drive the transition of tumor cells into CSCs which possibly controls the balance between metastasis and drug resistance in HCC.The challenge on balance between metastasis and drug resistance for tumor therapy was firstly reported by the present study.

Lipid droplets as metabolic determinants for stemness and chemoresistance in cancer

Previously regarded as simple fat storage particles,new evidence suggests thatlipid droplets(LDs)are dynamic and functional organelles involved in keycellular processes such as membrane biosynthesis,lipid metabolism,cellsignalling and inflammation.Indeed,an increased LD content is one of the mostapparent features resulting from lipid metabolism reprogramming necessary tosupport the basic functions of cancer cells.LDs have been associated to differentcellular processes involved in cancer progression and aggressiveness,such astumorigenicity,invasion and metastasis,as well as chemoresistance.Interestingly,all of these processes are controlled by a subpopulation of highly aggressivetumoral cells named cancer stem cells(CSCs),suggesting that LDs may befundamental elements for stemness in cancer.Considering the key role of CSCs onchemoresistance and disease relapse,main factors of therapy failure,the design ofnovel therapeutic approaches targeting these cells may be the only chance forlong-term survival in cancer patients.In this sense,their biology and functionalproperties render LDs excellent candidates for target discovery and design ofcombined therapeutic strategies.In this review,we summarise the currentknowledge identifying LDs and CSCs as main contributors to cancer aggressiveness,metastasis and chemoresistance.

Alternative models of cancer stem cells: The stemness phenotype model, 10 years later

The classical cancer stem cell(CSCs)theory proposed the existence of a rare but constant subpopulation of CSCs.In this model cancer cells are organized hierarchically and are responsible for tumor resistance and tumor relapse.Thus,eliminating CSCs will eventually lead to cure of cancer.This simplistic model has been challenged by experimental data.In 2010 we proposed a novel and controversial alternative model of CSC biology(the Stemness Phenotype Model,SPM).The SPM proposed a non-hierarchical model of cancer biology in which there is no specific subpopulation of CSCs in tumors.Instead,cancer cells are highly plastic in term of stemness and CSCs and non-CSCs can interconvert into each other depending on the microenvironment.This model predicts the existence of cancer cells ranging from a pure CSC phenotype to pure non-CSC phenotype and that survival of a single cell can originate a new tumor.During the past 10 years,a plethora of experimental evidence in a variety of cancer types has shown that cancer cells are indeed extremely plastic and able to interconvert into cells with different stemness phenotype.In this review we will(1)briefly describe the cumulative evidence from our laboratory and others supporting the SPM;(2)the implications of the SPM in translational oncology;and(3)discuss potential strategies to develop more effective therapeutic regimens for cancer treatment.

CK2αcauses stemness and chemotherapy resistance in liver cancer through the Hedgehog signaling pathway

Background:Liver cancer is one of the major causes of cancer-related deaths globally.Cancer cell stem-ness and chemotherapy resistance contribute to the high mortality.Although evidence indicates that the alpha subunit of protein kinase 2(CK2α)is involved in several human cancers,its function in liver cancer remains unknown.In the present study,we aimed to elucidate the role of CK2αin liver cancer.Methods:We examined the role of CK2αregulation in stemness and chemotherapy resistance capacity of liver cancer cells.MTT assays,tumor sphere formation assays,RT-PCR,flow cytometry,Western blotting assay,clonogenicity assay,matrigel invasion assay and bioinformatics were conducted in this study.Results:CK2αexpression in the liver cancer tissues was notably upregulated compared with that in the corresponding non-tumorous tissues.The overexpression of CK2αpromoted tumor sphere formation,increased the percentage of CD133(+)and side population cells,caused the resistance of liver cancer cells to 5-FU treatment,increased the expression levels of NANOG,OCT4,SOX2,Gli1 and Ptch1,and enhanced the ability of CD133(+)cell clone formation and invasion.Consistently,the downregulation of CK2αhad the opposite effects.CK2αsilencing inhibited the Hedgehog pathway by reducing the expression of Gli1 and Ptch1.Mechanistically,CK2αregulation on liver cancer cell stemness and chemotherapy resistance was found to be involved in the Hedgehog signaling pathway.Conclusions:Our study may bring some new insights into the occurrence of liver cancer.Furthermore,these findings suggest that targeting CK2αmay be a novel therapeutic strategy for patients with liver cancer.

Cryopreserved ovine spermatogonial stem cells maintain stemness and colony forming ability in vitro

Objective:To assess the effect of cryopreservation on stemness and proliferation potential of sheep spermatogonial stem cells(SSCs)in vitro.Methods:Sheep testicular cells were isolated and putative SSCs were enriched by the laminin-based differential plating method.Putative SSCs were co-cultured with the Sertoli cell feeder prepared by the Datura Stramonium Agglutinin(DSA-lectin)-based method.The cultured putative SSCs were cryopreserved in Dulbecco's Modified Eagle Medium-10%fetal bovine serum mixture(DMEM-10%FBS)media containing 10%dimethyl sulfoxide(DMSO)alone or 10%DMSO plus 200 mM trehalose.Cryopreserved putative SSCs were evaluated for their proliferation potential using in vitro culture and stemness by immunocytochemistry.Finally,the transfection ability of cryopreserved putative SSCs was analyzed.Results:We isolated 91%viable testicular cells from sheep testes.The majority of the laminin enriched cells expressed the SSC related marker,ITGA6.Co-culture of sheep putative SSCs with Sertoli cell feeder resulted in the generation of stable colonies,and the expression of SSC marker was maintained after several passages.A significantly higher number of viable putative SSCs was recovered from SSCs cryopreserved in media containing 10%DMSO and 200 mM trehalose compared to 10%DMSO alone(P<0.01).Cryopreserved putative SSCs formed colonies and showed SSC marker expression similar to the non-cryopreserved putative SSCs.The appearance of green fluorescent colonies over the Sertoli cell feeder indicated that cryopreserved sheep SSCs were successfully transfected.Conclusions:Cryopreserved putative SSCs can retain their stemness,colony forming ability,and transfection efficiency in vitro.Our research may help in the effective preservation of germplasm and the generation of transgenic ovine species.