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Ruan Z, Yang X, Cheng W. Cancer Manag Res. 2019;11:389–399. We, the Editors and Publisher of Cancer Management and Research, have retracted the following article. Following publication of the article, concerns were raised about the duplication of images from Figures 2, 4 and 5 with images from other unrelated articles. Specifically, Images for Figure 2I have been duplicated with images for Figure 3b from Qin S, Zhao Y, Lim G, et al. Circular RNA PVT1 acts as a competing endogenous RNA for miR-497 in promoting non-small cell lung cancer progression. Biomedicine & Pharmacotherapy. 2019;111:244-250. https://doi.org/10.1016/j.biopha.2018.12.007 and Figure 5 from Wang D, Gao Y, Zhang Y, Wang L, Chen G; Glypican-3 promotes cell proliferation and tumorigenesis through up-regulation of β-catenin expression in lung squamous cell carcinoma. Biosci Rep. 2019;39(6):BSR20181147. https://doi.org/10.1042/BSR20181147. Images for Figure 4G have been duplicated with images for Figure 3C from Xu X, Chen Y, Wang X, Mu X. Role of Hippo/YAP signaling in irradiation-induced glioma cell apoptosis. Cancer Manag Res. 2019;11:7577-7585. https://doi.org/10.2147/CMAR.S210825. Images for Figure 4H have been duplicated with images for Figures 2G and 4C from Xu, M, Gu M, Zhou J, Da J, Wang Z. Interaction of YAP1 and mTOR promotes bladder cancer progression. International Journal of Oncology. 2020;56:232-242. RETRACTED https://doi.org/10.3892/ijo.2019.4922 and Gao Y, Zhang G, Liu J, Li H. Tissue-specific transplantation antigen P35B functions as an oncogene and is regulated by microRNA-125a-5p in lung cancer. Oncology Reports. 2021;45:72. https://doi.org/10.3892/or.2021.8023, respectively. Images for Figure 5F have been duplicated with images for Figure 2C from Li Y, Tao C, Dai L, et al. MicroRNA-625 inhibits cell invasion and epithelial–mesenchymal transition by targeting SOX4 in laryngeal squamous cell carcinoma. Biosci Rep. 2019;39(1):BSR20181882. https://doi.org/10.1042/BSR20181882; Figure 2C from Gao Y, Zhang G, Liu J, Li H. Tissue-specific transplantation antigen P35B functions as an oncogene and is regulated by microRNA-125a-5p in lung cancer. Oncology Reports. 2021;45:72. https://doi.org/10.3892/or.2021.8023; Figure 2E from Wang L, Kong W, Liu B, Zhang X. Proliferating cell nuclear antigen promotes cell proliferation and tumorigenesis by up-regulating STAT3 in non-small cell lung cancer. Biomedicine & Pharmacotherapy. 2018;104:595-602. https://doi.org/10.1016/j.biopha.2018.05.071 and Figure 3D and 5D from Yuan L, Tian J. LIN28B promotes the progression of colon cancer by increasing B-cell lymphoma 2 expression. Biomedicine & Pharmacotherapy. 2018;103:355-361. https://doi.org/10.1016/j.biopha.2018.04.002. Images for Figure 5G have been duplicated with images for Figure 3I from Yang J, Yu L, Yan J, et al. Circular RNA DGKB Promotes the Progression of Neuroblastoma by Targeting miR-873/GLI1 Axis. Front. Oncol. 2020;10:1104. https://doi.org/10.3389/fonc.2020.01104 and Figure 5J from Du M, Shen P, Tan R, Wu D, Tu S. Aloe-emodin inhibits the proliferation, migration, and invasion of melanoma cells via inactivation of the Wnt/beta-catenin signaling pathway. Ann Transl Med. 2021;9(23):1722. https://doi.org/10.21037/atm-21-5437. The authors responded to our queries but were unable to provide a satisfactory explanation for the duplicated images or provide satisfactory data for the study. As verifying the validity of published work is core to the integrity of the scholarly record, we are therefore retracting the article and the authors were notified of this. We have been informed in our decision-making by our editorial policies and COPE guidelines. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as “Retracted”.

Introduction: Sulfatase 2 (SULF2), an endogenous extracellular sulfatase, can remove 6-O-sulfate groups of glucosamine residues from heparan sulfate (HS) chains to modulate the Wnt/β-catenin signaling pathway, which plays an important role in both liver carcinogenesis and embryogenesis. Side population (SP) cells are widely identified as stem-like cancer cells and are closely related to carcinoma metastasis, recurrence, and poor patient prognosis. However, the roles of SULF2 in SP cells of hepatomas are unclear, and the underlying mechanism is undefined. Objectives: This study aimed to compare the heterogeneity between SP cells and non-side population (NSP) cells derived from three different liver cancer cell lines and to elucidate the involvement of the SULF2-Wnt/β-catenin axis in liver cancer stem cells (CSCs) and its impact on the processes of carcinogenesis and invasiveness. Methods: In this work, three different liver cancer SP cells (HepG2, Huh7, and PRC/PRL/5) were sorted by flow cytometry. We also examined the migration and invasion behaviors of SP and NSP cells. To determine if this high tumorigenic potential of SP cells is correlated to SULF2, qPCR, western blotting, and immunofluorescence analysis were conducted. We also performed nude mouse xenograft experiments for in vivo analysis. Results: The results from the in vitro colony formation assay showed that SP cells exhibited a 2-fold higher colony formation efficiency compared to their NSP counterparts. The SP cells exhibited significantly higher potentials in terms of their migratory capacity and invasive ability compared to NSP cells. We found that higher expression of SULF2 in SP cells was associated with greater capabilities for clonogenicity, migration, and invasion. It was also linked to higher activation of the Wnt/β-catenin signaling pathway via stimulation of key downstream factors, particularly β-catenin, c-Myc, and cyclin D1. Further, a positive correlation between the upregulated SULF2 expression and tumorigenesis in the in vivo nude mouse xenograft models was demonstrated, highlighting that the potential underlying mechanism was Wnt/β-catenin signaling pathway activation. Conclusion: Our findings show that variable SULF2 expression was associated with differential activation of the Wnt/β-catenin signaling pathway, which could lead to behavioral differences between SP and NSP cells and also among the SP cells of the three liver cancer cell lines assessed. It was reasonably concluded that the SULF2-Wnt/β-catenin axis could play an important role in the tumorigenicity of liver cancer stem cells. [ABSTRACT FROM AUTHOR]

The endometrium is the inner mucosal lining of the uterus that undergoes extensive cyclic growth, regeneration, differentiation, and shedding throughout the menstrual cycle in response to steroid hormones. It repeatedly undergoes approximately 450 cycles of degeneration and regeneration in a woman's lifetime. Endometrial abnormalities can be associated with repeated embryo implantation failure, recurrent spontaneous abortion, and other physiological features responsible for female infertility. This significant regenerative capacity may occur as a result of tissue-resident stem cell populations within the endometrium. Indeed, the existence of endometrial stem cells was only observed in humans and rodents through several isolation and characterization methods in the last few years. Although endometrial stem cells share various biological characteristics with other types of mesenchymal stem cells, they also show some differences in phenotype, self-renewal, and multilineage differentiation potential. Extensive studies over many years on endometrial stem cells will provide new insights into the physiology and mechanisms underlying various gynaecological diseases related to endometrial abnormalities such as female infertility, endometriosis, and endometrial cancer. Here we summarized recent studies about cellular origins and biological characteristics of endometrial stem cells. We also reviewed various recent studies to improve our understanding of their physiological roles. Many preclinical studies on their potential therapeutic applications to various endometrial diseases that could lead to reproductive dysfunction were also reviewed.

Abstract Background Multiple myeloma (MM) is a hematopoietic malignancy for which proteasome inhibitors have become available in recent years. However, many patients develop resistance to these drugs during treatment. Therefore, it is important to elucidate the mechanisms underlying resistance acquisition by proteasome inhibitors. Side population (SP) cells, which have a high drug efflux capacity and hypoxic responses in the microenvironment have both provided important insights into drug resistance in MM; however, little is known about the characteristics of SP cells in hypoxic microenvironments. Methods We performed cDNA microarray analysis for SP and non‐SP obtained from RPMI‐8226 and KMS‐11 cell lines cultured for 48 h in normoxic and hypoxic conditions (1% O2). Genes specifically upregulated in hypoxic SP were examined. Results Our comprehensive gene expression analysis identified HMOX1, BACH2, and DUX4 as protein‐coding genes that are specifically highly expressed in SP cells under hypoxic conditions. We have shown that HMOX1/heme oxygenase‐1 (HMOX1/HO‐1) is induced by hypoxia‐inducible reactive oxygen species (ROS) and reduces ROS levels. Furthermore, we found that HMOX1 contributes to hypoxia‐induced resistance to proteasome inhibitors in vitro and in vivo. Excessive ROS levels synergistically enhance bortezomib sensitivity. In clinical datasets, HMOX1 had a strong and significantly positive correlation with MAFB but not MAF. Interestingly, hypoxic stimulation increased MAFB/MafB expression in myeloma cells; in addition, the knockdown of MAFB under hypoxic conditions suppressed HMOX1 expression. Conclusion These results suggest that the hypoxia‐ROS‐HMOX1 axis and hypoxia‐induced MafB may be important mechanisms of proteasome inhibitor resistance in hypoxic microenvironments.

This study delves into the synergy between Chinese female tennis players and the potential of Chansu-Medicated Serum in inhibiting breast cancer cell proliferation through apoptosis and G2 arrest. Chinese female tennis players have garnered international recognition for their achievements on the court and their philanthropic endeavors off it. This research investigates the intersection of their impact and the advancement of breast cancer research. Chansu-Medicated Serum, a traditional Chinese medicine derivative, presents promising mechanisms for inhibiting breast cancer cell proliferation, including apoptosis induction and G2 cell cycle arrest. By exploring this conjunction, we aim to shed light on the possible contributions of these athletes and traditional medicine to the ongoing battle against breast cancer. [ABSTRACT FROM AUTHOR]

Background: Multiple myeloma (MM) is a hematopoietic malignancy for which proteasome inhibitors have become available in recent years. However, many patients develop resistance to these drugs during treatment. Therefore, it is important to elucidate the mechanisms underlying resistance acquisition by proteasome inhibitors. Side population (SP) cells, which have a high drug efflux capacity and hypoxic responses in the microenvironment have both provided important insights into drug resistance in MM; however, little is known about the characteristics of SP cells in hypoxic microenvironments. Methods: We performed cDNA microarray analysis for SP and non‐SP obtained from RPMI‐8226 and KMS‐11 cell lines cultured for 48 h in normoxic and hypoxic conditions (1% O2). Genes specifically upregulated in hypoxic SP were examined. Results: Our comprehensive gene expression analysis identified HMOX1, BACH2, and DUX4 as protein‐coding genes that are specifically highly expressed in SP cells under hypoxic conditions. We have shown that HMOX1/heme oxygenase‐1 (HMOX1/HO‐1) is induced by hypoxia‐inducible reactive oxygen species (ROS) and reduces ROS levels. Furthermore, we found that HMOX1 contributes to hypoxia‐induced resistance to proteasome inhibitors in vitro and in vivo. Excessive ROS levels synergistically enhance bortezomib sensitivity. In clinical datasets, HMOX1 had a strong and significantly positive correlation with MAFB but not MAF. Interestingly, hypoxic stimulation increased MAFB/MafB expression in myeloma cells; in addition, the knockdown of MAFB under hypoxic conditions suppressed HMOX1 expression. Conclusion: These results suggest that the hypoxia‐ROS‐HMOX1 axis and hypoxia‐induced MafB may be important mechanisms of proteasome inhibitor resistance in hypoxic microenvironments. [ABSTRACT FROM AUTHOR]

The presence of key hypoxia regulators, namely, hypoxia-inducible factor (HIF)-1α or HIF-2α, in tumors is associated with poor patient prognosis. Hypoxia massively activates several genes, including the one encoding the BCRP transporter that proffers multidrug resistance to cancer cells through the xenobiotic efflux and is a determinant of the side population (SP) associated with cancer stem-like phenotypes. As natural medicine comes to the fore, it is instinctive to look for natural agents possessing powerful features against cancer resistance. Hypericin, a pleiotropic agent found in Hypericum plants, is a good example as it is a BCRP substrate and potential inhibitor, and an SP and HIF modulator. Here, we showed that hypericin efficiently accumulated in hypoxic cancer cells, degraded HIF-1/2α, and decreased BCRP efflux together with hypoxia, thus diminishing the SP population. On the contrary, this seemingly favorable result was accompanied by the stimulated migration of this minor population that preserved the SP phenotype. Because hypoxia unexpectedly decreased the BCRP level and SP fraction, we compared the SP and non-SP proteomes and their changes under hypoxia in the A549 cell line. We identified differences among protein groups connected to the epithelial–mesenchymal transition, although major changes were related to hypoxia, as the upregulation of many proteins, including serpin E1, PLOD2 and LOXL2, that ultimately contribute to the initiation of the metastatic cascade was detected. Altogether, this study helps in clarifying the innate and hypoxia-triggered resistance of cancer cells and highlights the ambivalent role of natural agents in the biology of these cells.

Cisplatin is a prevalent chemotherapeutic agent used for non-small cell lung cancer (NSCLC) that is difficult to treat by targeted therapy, but the emergence of resistance severely limits its efficacy. Thus, an effective strategy to combat cisplatin resistance is required. This study demonstrated that, at clinically achievable concentrations, the combination of selenium yeast (Se-Y) and fish oil (FO) could synergistically induce the apoptosis of cancer stem cell (CSC)-like A549 NSCLC sphere cells, accompanied by a reversal of their resistance to cisplatin. Compared to parental A549 cells, sphere cells have higher cisplatin resistance and possess elevated CSC markers (CD133 and ABCG2), epithelial–mesenchymal transition markers (anexelekto (AXL), vimentin, and N-cadherin), and cytoprotective endoplasmic reticulum (ER) stress marker (glucose-regulated protein 78) and increased oncogenic drivers, such as yes-associated protein, transcriptional coactivator with PDZ-binding motif, β-catenin, and cyclooxygenase-2. In contrast, the proapoptotic ER stress marker CCAAT/enhancer-binding protein homologous protein and AMP-activated protein kinase (AMPK) activity were reduced in sphere cells. The Se-Y and FO combination synergistically counteracted the above molecular features of A549 sphere cells and diminished their elevated CSC-like side population. AMPK inhibition by compound C restored the side population proportion diminished by this nutrient combination. The results suggest that the Se-Y and FO combination can potentially improve the outcome of cisplatin-treated NSCLC with phenotypes such as A549 cells. [ABSTRACT FROM AUTHOR]

A small population of cancer cells called cancer-initiating cells or cancer stem cells (CSCs) are involved in drug resistance, metastasis, and cancer relapse. Finding pathways that regulate CSC is very important for clinical therapy. ATP-binding cassette sub-family G member 2 (ABCG2) plays a role in side population (SP) cell formation and contributes to chemotherapy resistance in common forms of cancer. Yes-associated protein 1 (YAP1) is a major transcriptional effector of the Hippo pathway, which plays important roles in organ size control and tumorigenesis. In this study, we found ABCG2 and YAP1 were both overexpressed in lung cancer SP cells. Disruption of YAP1 expression by siRNA attenuated the expression of ABCG2 transcript and significantly reduced the percentage of SP cells and sphere formation in lung cancer cells. Overexpression of YAP1 in lung cancers led to an increase in ABCG2 expression and increased the percentage of SP cells. However, overexpression of YAP1 in purified non-SP cells did not increase ABCG2 expression and the percentage of SP cells, which may be due to the inhibition of YAP activity through phosphorylation. YAP1 directly transcriptionally regulated ABCG2 by binding to the promoter of ABCG2. Moreover, the YAP1 inhibitor verteporfin and YAP1 siRNA downregulated ABCG2 level through inhibition of YAP1 in lung cancer cells and sensitized them to the chemotherapy drug doxorubicin. Our study adds a new function for YAP1 that may be relevant to drug resistance and cancer therapy through regulation of ABCG2 and side population cell formation in lung cancer.

Side population (SP) is known to include therapy-resistant cells in various cancers. Here, we analyzed SP using multiple myeloma (MM) samples. The SP accounted for 2.96% in MM cells from newly diagnosed MM (NDMM). CD34 was expressed in 47.8% of SP cells, but only in 2.11% of bulk MM cells. CD34+ MM cells expressed more immature cell surface markers and a gene signature than CD34- MM cells. CD34+ but not CD34- MM cells possessed clonogenic activities and showed long-term self-renewal activities in xenotransplantation assays. Similarly, whereas 2.20% of MM cells were CD34+ in NDMM (n = 38), this proportion increased to 42.6% in minimal residual disease (MRD) samples (n = 16) (p < 0.001) and to 17.7% in refractory/relapsed MM (RRMM) (n = 30) (p < 0.01). Cell cycle analysis showed that 24.7% of CD34+ MM cells from NDMM were in G0 phase while this proportion was 54.9% in MRD (p < 0.05) and 14.5% in RRMM, reflecting the expansion of MM. Together, CD34+ MM cells with long-term self-renewal activities persist as MRD in cell cycle quiescence or remain as therapy-resistant cells in RRMM, substantiating the necessity of targeting this population to improve clinical outcomes of MM. [ABSTRACT FROM AUTHOR]

Background: The dermal aging process and the formation of deep wrinkles are a biological involution that also involves the regeneration system of cells immersed in the extracellular matrix and the papillary dermis. The progressive loss of niches of adult stem cells (MSCs) is more evident after the first third of life; it increases the phenotypic expression and the characteristics of the tissue senescence process. The purpose of this study was to clinically demonstrate that in viable micrograft there may be an improvement of deep wrinkles and surrounding tissues. Methods: This study involved 11 female patients who underwent the correction of deep dermal wrinkles through a suspension containing 0.8 mL of viable micrografts in a 5 mL plasma gel scaffold, obtained from the centrifugation of a 20 cc venous sample peripheral blood, gelled by heat in a dry steriliser and the buffy coat coming from the same venous sample, in order verify overtime the improvement of the interested anatomical area. Individual signs of wrinkles and the degree of correction obtained for each treatment and each area were objectively evaluated by using a 10-0 visual analog scale (VAS), Modified Vancouver scale and Berardesca's scale. Results: With this technique excellent results were obtained. In fact, wrinkles were improved, as well as surrounding tissues, even after 60 days, as shown by the Berardesca's, VAS and Modified Vancouver scales. Conclusion: This retrospective clinical evaluation allowed us to consider the excellent clinical results obtained with this method for the treatment of deep wrinkles and surrounding tissues, through a suspension of progenitors with MSCs derived from adipose tissue (ADSCa) in a not inflammatory plasma gel scaffold combined with buffy coat.

The multiple myeloma (MM) landscape has changed in the last few years, but most patients eventually relapse because current treatment modalities do not target clonogenic stem cells, which are drug-resistant and can self-renew. We hypothesized that side population (SP) cells represent myeloma clonogenic stem cells and, searching for new treatment strategies, analyzed the anti-myeloma activity of natural killer (NK) cells against clonogenic cells. Activated and expanded NK cells (NKAE) products were obtained by co-culturing NK cells from MM patients with K562-mb15-41BBL cell line and characterized by flow cytometry. Functional experiments against MM cells were performed by Eu-TDA release assays and methylcellulose clonogenic assays. Side population was detected by Dye Cycle Violet labeling and then characterized by flow cytometry and RNA-Seq. Self-renewal capacity was tested by clonogenic assays. Sorting of both kind of cells was performed for time-lapse microscopy experiments. SP cells exhibited self-renewal potential and overexpressed genes involved in stem cell metabolism. NK cells from MM patients exhibited dysregulation and had lower anti-tumor potential against clonogenic cells than healthy donors' NK cells. Patients' NK cells were activated and expanded. These cells recovered cytotoxic activity and could specifically destroy clonogenic myeloma cells. They also had a highly cytotoxic phenotype expressing NKG2D receptor. Blocking NKG2D receptor decreased NK cell activity against clonogenic myeloma cells, and activated NK cells were able to destroy SP cells, which expressed NKG2D ligands. SP cells could represent the stem cell compartment in MM. This is the first report describing NK cell activity against myeloma clonogenic cells. [ABSTRACT FROM AUTHOR]

The aim of this clinical study was to demonstrate that through a micrograft of viable adipose tissue cells microfiltered at 50 microns to exclude fibrous shoots and cell debris in a suspension of cross-linked hyaluronic acid, we were able to improve visible imperfections of the dermis and to improve clinically observable wrinkles, with a beneficial effect also in the extracellular matrix (ECM). Background and Objectives: With the passage of time, the aging process begins, resulting in a progressive impairment of tissue homeostasis. The main reason for the formation of wrinkles is the involution of the papillary dermis, as well as the loss of stem cell niches with compromise of the extra-cytoplasmic matrix (ECM), and the loss of hyaluronic acid, which helps to maintain the shape and resistance and that is contained in the connective tissue. Materials and Methods: This study involved 14 female patients who underwent dermal wrinkle correction and bio-regeneration over the entire facial area through a suspension containing 1.0 mL of viable micrografts from adipose tissue in a 1.0 mL cross-linked hyaluronic acid. To verify the improvement of the anatomical area concerned over time, the various degrees of correction obtained for wrinkles, and in general for texture, were objectively evaluated by using a Numeric Rating scale (NRS) 10–0, a modified Vancouver scale and a Berardesca scale. Results: The Berardesca, NRS and Modified Vancouver scales showed that with this technique it was possible to obtain excellent results both when the suspension was injected into wrinkles with the linear retrograde technique, and when it was injected with the micropomphs technique to correct furrows, with the intent to revitalize the tissue through progenitors with adult stemness markers. Conclusions: The combination of microfragmented and microfiltered adipose tissue and cross-linked hyaluronic acid at 50 microns is safe new method to treat soft tissue defects such as deep wrinkles.

DyeCycle Violet efflux, caused by ATP-binding cassette transporters activity, was analyzed in human colorectal adenocarcinoma cell lines SW480, HT-29, Caco-2 by means of a FACSAria III flow cytometer and an ImageStreamX Mk II imaging flow cytometer. Besides similarity of cytometry data obtained by two instruments, the use of imaging flow cytometry made it possible to characterize the morphology of side population cells, as well as morphology of other cell populations differing in the degree of dye accumulation. The population of cells, which are smaller than the side population cells and practically do not take the dye, is of the special interest. Probably, this population may contribute to the tumor resistance to chemotherapy. [ABSTRACT FROM AUTHOR]

Cancer stem cells (CSC) and genes have been linked to cancer development and therapeutic resistance, but the signaling mechanisms regulating CSC genes and phenotype are incompletely understood. CK2 has emerged as a key signal serine/threonine kinase that modulates diverse signal cascades regulating cell fate and growth. We previously showed that CK2 is often aberrantly expressed and activated in head and neck squamous cell carcinomas (HNSCC), concomitantly with mutant (mt) tumor suppressor TP53, and inactivation of its family member, TAp73. Unexpectedly, we observed that classical stem cell genes Nanog, Sox2, and Oct4, are overexpressed in HNSCC with inactivated TAp73 and mtTP53. However, the potential relationship between CK2, TAp73 inactivation, and CSC phenotype is unknown. We reveal that inhibition of CK2 by pharmacologic inhibitors or siRNA inhibits the expression of CSC genes and side population (SP), while enhancing TAp73 mRNA and protein expression. Conversely, CK2 inhibitor attenuation of CSC protein expression and the SP by was abrogated by TAp73 siRNA. Bioinformatic analysis uncovered a single predicted CK2 threonine phosphorylation site (T27) within the N-terminal transactivation domain of TAp73. Nuclear CK2 and TAp73 interaction, confirmed by co-immunoprecipitation, was attenuated by CK2 inhibitor, or a T27A point-mutation of this predicted CK2 threonine phospho-acceptor site of TAp73. Further, T27A mutation attenuated phosphorylation, while enhancing TAp73 function in repressing CSC gene expression and SP cells. A new CK2 inhibitor, CX-4945, inhibited CSC related SP cells, clonogenic survival, and spheroid formation. Our study unveils a novel regulatory mechanism whereby aberrant CK2 signaling inhibits TAp73 to promote the expression of CSC genes and phenotype.

Abstract Background During sprouting angiogenesis, stalk cells, localized behind tip cells, generate endothelial cells (ECs) for the elongation of new vessels. We hypothesized that stalk cells may have endothelial progenitor cell properties because of their highly proliferative ability. We conducted Hoechst dye DNA staining in ECs of preexisting blood vessels from hind limb muscle and found that endothelial-side population (E-SP) cells, which efflux Hoechst rapidly with abundant ABC transporters, show highly producing ability of ECs. We previously showed the existence of E-SP cells in hind limb muscle, retina, and liver, but not in other tissues such as adipose tissue, skin, and placenta. Methods We investigated the existence of E-SP cells and analyzed their proliferative ability among CD31+CD45− ECs from adipose tissue, skin, and placenta of adult mice. We also analyzed the neovascular formation of E-SP cells from adipose tissue in vivo. Results We detected E-SP cells in all tissues examined. However, by in vitro colony formation analysis on OP9 cells, we found that E-SP cells from adipose tissue and skin, but not from placenta, have highly proliferative ability. Moreover, E-SP cells from adipose tissue could contribute to the neovascular formation in hind limb ischemia model. Conclusion The adipose tissue and skin are available sources to obtain endothelial stem cells for conducting therapeutic angiogenesis in regenerative medicine.

Zhengyi Ruan, Xingyu Yang, Weiwei Cheng Department of Obstetrics and Gynaecology, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China Background: Although surgery, chemotherapy, and radiotherapy eliminate clinically apparent ovarian tumor, the 5-year survival rate is no more than 45%. Cancer stem cells (CSCs) have been identified for precaution of tumor metastasis and recurrence in many kinds of cancers including ovarian cancer. Aim: This study aims to explore the function of OCT4, a CSC marker, in ovarian cancer progression and to investigate its underlying mechanism. Materials and methods: By Hoechst side population (SP) technique, CSC-like SP cells from human ovarian cancer SKOV3 and A2780 cells were isolated and used for this study. shRNA and lentivirus targeting human OCT4 gene were used to knock down OCT4 in SP cells and upregulate OCT4 in non-SP (NSP) cells stably. Peficitinib was used to inhibit JAK/STAT signaling. Cell counting kit-8, flow cytometry, and in vivo xenograft model were used to evaluate the effects of OCT4/JAK/STAT on the viability, drug resistance, apoptosis, cycle, and tumorigenesis of the SP cells. Immunofluorescence staining was used to detect the location of STAT6. Results: Results showed that OCT4 was upregulated in the SP of SKOV3 and A2780 cells when compared with the NSP cells. Downregulation of OCT4 inhibited SP cell viability, tumorigenesis, and reduced cell drug resistance and induced a G2/M phase arrest, while upregulation of OCT4 conferred NSP cell malignant features. Besides, OCT4 upregulation in NSP cells increased the phosphorylated levels of proteins in JAK and STAT families, especially in JAK1 and STAT6. Furthermore, the roles of apoptosis inhibition and viability, invasion, and tumorigenesis promotions induced by OCT4 in NSP cells were all abolished when adding peficitinib. Conclusion: Our study demonstrated that OCT4 accelerated ovarian cancer progression through activating JAK/STAT signaling pathway. Keywords: OCT4, JAK/STAT signaling, ovarian cancer, side population

Numerous studies have proven the high resistance of cancer stem cells (CSCs) to a single-dose low-LET ionizing radiation exposure in vitro. These data are the basis for the assumption about the important role of CSCs in cancer recurrence after conventional radiation therapy. However, the patterns and mechanisms of fractionated radiation effects on this population of cells have not been studied enough, and there are only a few publications regarding cervical cancer. Therefore, the purpose of this work is to elucidate the quantitative changes in the CSC population after low-LET radiation exposure using the conventional fractionation regimen in vitro (in cervical cancer cell lines HeLa and SiHa) and in vivo (in cervical scrapings from patients with squamous cell cervical cancer during radiation therapy). Using flow cytometry, the proportion of CSCs was measured in these cell lines after each dose fraction until a cumulative dose of 10 Gy was reached, and in clinical samples of 26 patients before treatment and after irradiation at a cumulative dose of 10 Gy to point A. CSCs were identified in cell cultures by the ability of these cells to pump out the fluorescent dye Hoechst 33 342 and form a side population (SP) and in cervical scrapings by the CD44+CD24low immunophenotype. A statistically significant increase in the proportion of CSCs was found after fractionated irradiation of cervical cell cultures in the range of 2–10 Gy, as compared with the nonirradiated control. High individual variability in the proportion of CD44+CD24low CSCs was detected in cervical scrapings before treatment and after radiation exposure. An irradiation-induced increase in this indicator was observed in 38% of patients; in other patients, a decrease in this indicator was found after irradiation at a cumulative dose of 10 Gy or its preservation at the initial level. A high inverse correlation was observed between the CSC proportion before treatment with its change after irradiation (R = –0.71; p < 0.0001). The results indicate significant individual differences in the response of cervical CSCs to radiation treatment and substantiate the fundamental possibility of further investigation of the prognostic significance of CSC quantitative changes after the first sessions of radiotherapy with regard to the short- and long-term results of treatment. [ABSTRACT FROM AUTHOR]

Purpose: Risk stratification in patients with multiple myeloma (MM) remains a challenge. As clinicopathological characteristics have been demonstrated insufficient for exactly defining MM risk, and molecular biomarkers have become the focuses of interests. Prognostic predictions based on gene expression profiles (GEPs) have been the most accurate to this day. The purpose of our study was to construct a risk score based on stemness genes to evaluate the prognosis in MM. Materials and Methods: Bioinformatics studies by ingenuity pathway analyses in side population (SP) and non-SP (MP) cells of MM patients were performed. Firstly, co-expression network was built to confirm hub genes associated with the top five Kyoto Encyclopedia of Genes and Genomes pathways. Functional analyses of hub genes were used to confirm the biologic functions. Next, these selective genes were utilized for construction of prognostic model, and this model was validated in independent testing sets. Finally, five stemness genes (ROCK1, GSK3B, BRAF, MAPK1 and MAPK14) were used to build a MM side population 5 (MMSP5) gene model, which was demonstrated to be forcefully prognostic compared to usual clinical prognostic parameters by multivariate cox analysis. MM patients in MMSP5 low-risk group were significantly related to better prognosis than those in high-risk group in independent testing sets. Conclusion: Our study provided proof-of-concept that MMSP5 model can be adopted to evaluate recurrence risk and clinical outcome for MM. The MMSP5 model evaluated in different databases clearly indicated novel risk stratification for personalized anti-MM treatments. [ABSTRACT FROM AUTHOR]

The adult mammalian heart has a limited regenerative capacity. Therefore, identification of endogenous cells and mechanisms that contribute to cardiac regeneration is essential for the development of targeted therapies. The side population (SP) phenotype has been used to enrich for stem cells throughout the body; however, SP cells isolated from the heart have been studied exclusively in cell culture or after transplantation, limiting our understanding of their function in vivo. We generated a new Abcg2‐driven lineage‐tracing mouse model with efficient labeling of SP cells. Labeled SP cells give rise to terminally differentiated cells in bone marrow and intestines. In the heart, labeled SP cells give rise to lineage‐traced cardiomyocytes under homeostatic conditions with an increase in this contribution following cardiac injury. Instead of differentiating into cardiomyocytes like proposed cardiac progenitor cells, cardiac SP cells fuse with preexisting cardiomyocytes to stimulate cardiomyocyte cell cycle reentry. Our study is the first to show that fusion between cardiomyocytes and non‐cardiomyocytes, identified by the SP phenotype, contribute to endogenous cardiac regeneration by triggering cardiomyocyte cell cycle reentry in the adult mammalian heart. [ABSTRACT FROM AUTHOR]

• Co-activation of both Akt/mTOR and Wnt/ β-catenin signaling pathways was found in 14.4% of patients with HCC. • Co-activation of these pathways confers worse survival compared to Akt/mTOR or Wnt/β-catenin activation alone. • Akt/β-catenin tumors contained a subpopulation of cells with stem/progenitor-like characteristics. • MDR1 was the main driver of SP phenotype in the Akt/β-catenin-driven HCC. • Activated Stat3 regulates the self-renewing and tumorigenic population of SP/CD44+ cells in Akt/β-catenin tumors. Hepatic resection and liver transplantation with adjuvant chemo- and radiotherapy are the mainstay of hepatocellular carcinoma (HCC) treatment, but the 5-year survival rate remains poor because of frequent recurrence and intrahepatic metastasis. Only sorafenib and lenvatinib are currently approved for the first-line treatment of advanced, unresected HCC, but they yield modest survival benefits. Thus, there is a need to identify new therapeutic targets to improve current HCC treatment modalities. The HCC tumor model was generated by hydrodynamic transfection of AKT1 and β-catenin (CTNNB1) oncogenes. Cancer cells with stemness properties were characterized following isolation using side population (SP) and CD44 surface markers by flow cytometry. The effect of Jak/Stat inhibitors was analyzed in vitro by using tumorsphere culture and in vivo using an allograft mouse model. Co-activation of both Wnt/β-catenin and Akt/mTOR pathways was found in 14.4% of our HCC patient cohort. More importantly, these patients showed poorer survival than those with either Wnt/β-catenin or Akt/mTOR pathway activation alone, demonstrating the clinical relevance of our study. In addition, we observed that Akt/β-catenin tumors contained a subpopulation of cells with stem/progenitor-like characteristics identified through SP analysis and expression of the cancer stem cell-like marker CD44, which may contribute to tumor self-renewal and drug resistance. Consequently, we identified small molecule inhibitors of the Jak/Stat pathway that demonstrated efficacy in mitigating tumor proliferation and formation in Akt/β-catenin-driven HCC. In conclusion, we have shown that Akt/β-catenin tumors contain a subpopulation of tumor-initiating cells with stem/progenitor-like characteristics which can be effectively targeted with inhibitors of the Jak/Stat pathway, demonstrating that inhibition of the Jak/Stat pathway could be an alternative method to overcome drug resistance and effectively treat Akt/β-catenin-driven HCC tumors. The prognosis for patients with hepatocellular carcinoma is poor, partly because of the lack of effective treatment options for those with more advanced disease. In this study, we identified a subpopulation of cancer cells with stem cell-like properties that were critical for tumor maintenance and growth in a mouse model of hepatocellular carcinoma. Through further experiments, we demonstrated that the Jak/Stat pathway is a promising therapeutic target in hepatocellular carcinoma. [ABSTRACT FROM AUTHOR]

Cancer stem cells (CSCs) have emerged as an attractive research interest due to their prominent role in development of the tumors. CSCs are rare dormant cells that can self-renew and maintain tumor development and heterogeneity. A better understanding of CSCs can improve tumor classification and contribute toward the development of novel therapeutic approaches to fight cancer. Hence, it is of immense importance to comprehend the basic function of CSCs in tumor formation, which can only be possible by devising perfected methodologies to isolate, detect, and characterize them. In this chapter, we outline the key protocols to culture, identify, and isolate CSCs from solid tumors to further advance basic and clinical investigation related to CSCs and their role in tumor biology., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Over the past 20 years, there has been a lot of interest in the study and investigation of cancer stem cells (CSCs) or tumor-initiating cells (TICs). CSCs are rare, dormant cells and able to self-renew and maintain tumor development and heterogeneity. A new age of basic and clinical cancer research, reclassification of human tumors, and the development of novel therapeutic approaches will undoubtedly result from a better knowledge of CSCs. In order to develop effective and therapeutic strategies to treat cancer, it is crucial to understand the basic characteristics of CSCs, their importance to cancer therapy, and methodologies to isolate, detect, and characterize them. Here, we outline the main methods and protocols to identify, isolate, and culture CSCs from primary tumors., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Melanoma is the most aggressive form of skin cancer. Melanoma stem cells (MSCs) are one of the driving forces of melanoma invasion and metastasis. Therefore, it is of great significance to explore the mechanisms that maintain the stemness of MSCs. In this study, CD147-positive (CD147+) MSCs derived from A375 cell line were characterized., Methods: Side population (SP) and non-SP cells were sorted from A375 cells. Quantitative real-time polymerase chain reaction and Western blot analysis were conducted to determine the expression of CD147 in SP and non-SP cells. Subsequently, CD147+ and CD147-negative (CD147-) cells were isolated from SP cells. Stem cell characteristics and metastatic potential of CD147+/- antigen-presenting cells were identified by sphere-forming, wound-healing, and transwell assays. Western blot analysis was performed to evaluate the protein levels of transforming growth factor-beta1 (TGFβ1) and neurogenic locus notch homolog protein 1 (Notch1) signaling pathway. Xenograft tumor experiments were conducted to investigate the tumorigenic capacity of CD147+ cells in vivo ., Results: CD147 was highly expressed in SP cells of A375 cell line. CD147+ cells have stronger abilities for sphere forming, migration, and invasion in vitro . The protein levels of TGFβ1, notch1, jagged1, and Hes1 were higher in CD147+ cells than in CD147- cells. Moreover, the CD147+ cells showed stronger tumorigenic and metastatic potential in vivo ., Conclusion: SP cells of A375 cell line expressed high levels of CD147, and CD147+ SP cells possessed much stronger stem-like characteristics and motility, which is linked to the activation of TGFβ and notch pathways., Competing Interests: The authors state that there was no conflict of interest to declare.

Cancer stem cells (CSCs) are tumor cells with initiating ability, self‐renewal potential, and intrinsic resistance to conventional therapeutics. Efficient isolation and characterization of CSCs pave the way for more comprehensive knowledge about tumorigenesis, heterogeneity, and chemoresistance. Also a better understanding of CSCs will lead to novel era of both basic and clinical cancer research, reclassification of human tumors, and development of innovative therapeutic strategies. Finding novel diagnostic and effective therapeutic strategies also enhance the success of treatment in cancer patients. There are various methods based on the characteristics of the CSCs to detect and isolate these cells, some of which have recently developed. This review summarized current techniques for effective isolation and characterization of CSCs with a focus on advantages and limitations of each method with clinical applications. [ABSTRACT FROM AUTHOR]

Abstract Comparison of studies of cells derived from normal and pathological tissues of the same organ can be fraught with difficulties, particular with cancer where a number of different diseases are considered cancer within the same tissue. In the thyroid, there are 4 main types of cancer, three of which arise from follicular epithelial cells; papillary and follicular which are classified as differentiated, and anaplastic which is classified as undifferentiated. One assay that can be utilised for isolation of cancer stem cells is the side population (SP) assay. However, SP studies have been limited in part due to lack of optimal isolation strategies and in the case of anaplastic thyroid cancer (ATC) are further compounded by lack of access to ATC tumors. We have used thyroid cell lines to determine the optimal conditions to isolate viable SP cells. We then compared SP cells and NSP cells (bulk tumour cells without the SP) of a normal thyroid cell line N-thy ori-3-1 and an anaplastic thyroid cancer cell line SW1736 and showed that both SP cell populations displayed higher levels of stem cell characteristics than the NSP. When we compared SP cells of the N-thy ori-3-1 and the SW1736, the SW1736 SP had a higher colony forming potential, expressed higher levels of stem cell markers and CXCR4 and where more migratory and invasive, invasiveness increasing in response to CXCL12. This is the first report showing functional differences between ATC SP and normal thyroid SP and could lead to the identification of new therapeutic targets to treat ATC. [ABSTRACT FROM AUTHOR]

Endometrial regeneration has long been proposed to be mediated by stem cells, but the isolation of endometrial stem cells has been hampered by a lack of validated markers. Specific markers would enable isolation of these stem cells, thereby promoting advancements in regenerative medicine for the treatment of endometrial diseases and dysfunctions. We sought to investigate the regenerative ability of human endometrial positive for sushi domain containing 2/intercellular adhesion molecule 1 (SUSD2+/ICAM1+) cells and Side Population cell lines in a xenograft mice model. The injection of total endometrial cell suspensions and Side Population cell lines under kidney capsules induced neoformation of human endometrium verified by the presence of typical endometrial markers (vimentin, cytokeratin 18, and progesterone receptor) by immunofluorescence. Total endometrial cell types promoted a better reconstitution in comparison to injecting ICAM1+ and SUSD2+ cells alone. The endometrial fraction is probably acting as a niche, resulting in increased reconstruction efficiency of pure fractions. Human engrafted cells were localized near blood vessels and induced the proliferation of surrounding cells. Our results suggest that human endometrial Side Population, a heterogeneous population possibly harboring endometrial stem cells, has the optimum capacity to regenerate endometrial-like tissue. In contrast, cells positive for single stem cell markers SUSD2 and ICAM1 have minimally functional regenerative capacities in the absence of niche-like cells. [ABSTRACT FROM AUTHOR]