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.

How the interplay among the tumor microenvironment and the gut microbiota influences the stemness of colorectal cancer cells

Colorectal cancer(CRC)remains the third most prevalent cancer disease and involves a multi-step process in which intestinal cells acquire malignant characteristics.It is well established that the appearance of distal metastasis in CRC patients is the cause of a poor prognosis and treatment failure.Nevertheless,in the last decades,CRC aggressiveness and progression have been attributed to a specific cell population called CRC stem cells(CCSC)with features like tumor initiation capacity,self-renewal capacity,and acquired multidrug resistance.Emerging data highlight the concept of this cell subtype as a plastic entity that has a dynamic status and can be originated from different types of cells through genetic and epigenetic changes.These alterations are modulated by complex and dynamic crosstalk with environmental factors by paracrine signaling.It is known that in the tumor niche,different cell types,structures,and biomolecules coexist and interact with cancer cells favoring cancer growth and development.Together,these components constitute the tumor microenvironment(TME).Most recently,researchers have also deepened the influence of the complex variety of microorganisms that inhabit the intestinal mucosa,collectively known as gut microbiota,on CRC.Both TME and microorganisms participate in inflammatory processes that can drive the initiation and evolution of CRC.Since in the last decade,crucial advances have been made concerning to the synergistic interaction among the TME and gut microorganisms that condition the identity of CCSC,the data exposed in this review could provide valuable insights into the biology of CRC and the development of new targeted therapies.

ROS and Lipid Droplet accumulation induced by high glucose exposure in healthy colon and Colorectal Cancer Stem Cells

Lipid Droplets(LDs)are emerging as crucial players in colon cancer development and maintenance.Their expression has been associated with high tumorigenicity in Cancer Stem Cells(CSCs),so that they have been proposed as a new functional marker in Colorectal Cancer Stem Cells(CR-CSCs).They are also indirectly involved in the modulation of the tumor microenvironment through the production of pro-inflammatory molecules.There is growing evidence that a possible connection between metabolic alterations and malignant transformation exists,although the effects of nutrients,primarily glucose,on the CSC behavior are still mostly unexplored.Glucose is an essential fuel for cancer cells,and the connections with LDs in the healthy and CSC populations merit to be more deeply investigated.Here,we showed that a high glucose concentration activated the PI3K/AKT pathway and increased the expression of CD133 and CD44v6 CSC markers.Additionally,glucose was responsible for the increased amount of Reactive Oxygen Species(ROS)and LDs in both healthy and CR-CSC samples.We also investigated the gene modulations following the HG treatment and found out that the healthy cell gene profile was the most affected.Lastly,Atorvastatin,a lipidlowering drug,induced the highest mortality on CR-CSCs without affecting the healthy counterpart.

IL-13/IL-13RA2 signaling promotes colorectal cancer stem cell tumorigenesis by inducing ubiquitinated degradation of p53

Cancer stem cells(CSCs)are considered tumor-initiating cells and the main drivers of disease progression.Targeting these rare cancer cells,however,remains challenging with respect to therapeutic benefit.Here,we report the up-regulation of IL-13RA2 expression in colorectal cancer(CRC)tissues and spheroid cells.The expression of IL-13RA2 was positively correlated with canonical stemness markers in CRC.We further demonstrated that the level of IL-13 was up-regulated in the serum of CRC patients.Biologically,recombinant IL-13(rIL13)stimulation promoted the sphere formation,proliferation,and migration of CRC cells in vitro and enhanced tumorigenesis in vivo.This phenotype could be reversed by knocking down IL-13RA2.Mechanistically,IL-13 activated autophagy by inducing LC3I/LC3II transformation in CRC-CSCs,which was crucial for the biological functions of IL-13.We further demonstrated that IL-13RA2 acted as a modular link of the E3 ligase UBE3C and the substrate p53 protein,enhancing the interaction of UBE3C and p53,thereby inducing the K48-linked ubiquitination of p53.In conclusion,the IL-13/IL-13RA2 signaling cascade promotes CRC-CSC self-renewal and tumorigenesis by inducing p53 ubiquitination,adding an important layer to the connection between IL-13 and p53,which can be translated into novel targeted therapies.

Molecular insights into colorectal cancer stem cell regulation by environmental factors

Colorectal cancer remains a signifi cant cause of cancer-related mortality worldwide,mainly because of tumor relapse and metastases.Cancer stem cells(CSCs)are considered to be the main cause of resistance to chemotherapeutic agents,as well as being responsible for distant metastases.Although CSCs themselves possess innate abilities for self-renewal and differentiation,the environment surrounding CSCs provides oxygen,nutrients and secreted factors,and also supports angiogenesis,thus it's responsible for maintaining their CSC properties.Furthermore,extensive investigations have revealed that obesity,accompanied by excess visceral adipose tissue,induces chronic infl ammation,and is linked to the risk and progression of several gastrointestinal cancers,through modulating the capacities of the CSCs.This review presents the evidence linking colorectal CSCs and their environment and summarizes our current understanding of the molecular mechanisms underlying this relationship.