Differentiation Of Cancer Stem Cells Research Articles

Vitamin D Effects on Cell Differentiation and Stemness in Cancer.

Vitamin D3 is the precursor of 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), a pleiotropic hormone that is a major regulator of the human genome. 1,25(OH)2D3 modulates the phenotype and physiology of many cell types by controlling the expression of hundreds of genes in a tissue- and cell-specific fashion. Vitamin D deficiency is common among cancer patients and numerous studies have reported that 1,25(OH)2D3 promotes the differentiation of a wide panel of cultured carcinoma cells, frequently associated with a reduction in cell proliferation and survival. A major mechanism of this action is inhibition of the epithelial–mesenchymal transition, which in turn is largely based on antagonism of the Wnt/β-catenin, TGF-β and EGF signaling pathways. In addition, 1,25(OH)2D3 controls the gene expression profile and phenotype of cancer-associated fibroblasts (CAFs), which are important players in the tumorigenic process. Moreover, recent data suggest a regulatory role of 1,25(OH)2D3 in the biology of normal and cancer stem cells (CSCs). Here, we revise the current knowledge of the molecular and genetic basis of the regulation by 1,25(OH)2D3 of the differentiation and stemness of human carcinoma cells, CAFs and CSCs. These effects support a homeostatic non-cytotoxic anticancer action of 1,25(OH)2D3 based on reprogramming of the phenotype of several cell types.

Abstract 1746: The BET inhibitor JQ-1 enhances radio-sensitivity in pediatric cancer cell lines by sustained p-gH2AX expression and enhanced differentiation

Abstract Purpose: Pediatric high grade gliomas (HGG), high risk medulloblastomas (MB) and neuroblastomas (NB) are malignant neurological tumors with poor prognosis despite major advancements in current therapeutic interventions. The standard of care therapy for such high risk tumors includes surgical resection, when possible, and radio-therapy with or without chemo-therapy. Therapeutic failure may be due to radio- and/or chemo-resistance and the maintenance of an aggressive stem-like sub-population of cells within the bulk tumors. Epigenetic deregulation is implicated in pediatric neurological cancer malignancies where the bromo- and extra-terminal domain (BET) protein activity may play a role in histone H3K27 acetylation leading to tumorigenesis and radio-resistance. Methods and Results: We used the BET inhibitor JQ-1 to determine the radio-sensitizing effect on a panel of human pediatric neurological cancer cell lines including: NB (IMR-32 and SKNSH), MB (D556 and D283) and HGG (GBM01 and DIPG07). Cells were seeded 24 hours (h) before treatment with 1 µM dose of JQ-1 for an additional 24 h before irradiation (IR) with 6Gy (JL Shepherd Mark 1 137Cs Irradiator). IncuCyte (Essen Biosciences, Ann Arbor, MI) live cell imaging recorded cellular proliferation (confluency) over 6 days post IR, revealing that while single treatment with JQ-1 or 6Gy irradiation alone significantly reduced cell proliferation in all the tested cell lines, the combination of JQ-1 pre-treatment followed by 6Gy IR differentially impaired proliferation capacity in all cell lines except DIPG07 by further reducing cell proliferation. To determine the mechanism of radio-sensitization induced by JQ-1, Western blot and Immunofluorescence analysis revealed increased p-γH2AX foci at 24 h post IR in JQ-1 pre-treated cells. Furthermore, the stem cell maintenance and tumorigenic proteins OCT-4, MYCN, HSP90, L1-CAM, RAB5C and FABP5 were differentially expressed after JQ-1 treatment. Next we assessed the effect of JQ-1 on cellular migration and stem-cell maintenance using the ‘wound-healing' scratch and tumor-sphere self-renewal assays, respectively. Cell migration was significantly (P < 0.05) inhibited with JQ-1 in both human NB (IMR-32 and SKNSH) and MB (D556 and D283) cell lines. Tumor-sphere formation efficiency was significantly (P < 0.05) reduced in IMR-32, SKNSH, D556, D283 and DIPG cells after treatment with JQ-1. Morphological cellular differentiation, evidenced by long neurite extensions, was induced after JQ-1 treatment in the D556, IMR-32 and SKNSH cells. Conclusions: Our data show potent anti-stem cell activity as well as decreased proliferation, migration and enhanced radiosensitivity following JQ-1 treatment. These effects may be due to delayed DNA repair mechanisms, differential expression of stem cell maintenance and tumorigenic proteins and induced differentiation of the malignant cancer stem cells. Citation Format: Tamara Mary Abou-Antoun, Jad Abdallah, Amanda R. Khater, Sarra El-Soussi, Aysegul Balyimez, Shinjini Ganguly, Anthony Sandler, Omar Mian. The BET inhibitor JQ-1 enhances radio-sensitivity in pediatric cancer cell lines by sustained p-gH2AX expression and enhanced differentiation [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1746.

Regulating Stem Cell-Related Genes Induces the Plastic Differentiation of Cancer Stem Cells to Treat Breast Cancer

Relapse of cancer is associated with multidirectional differentiation and unrestricted proliferative replication potential of cancer stem cells. Herein, we propose the plastic differentiation strategy for irreversible differentiation of cancer stem cells; further, salinomycin and its newly constructed functional liposomes are used to implement this strategy. Whole gene, cancer stem cell-related RNA, and protein expression analyses reveal that salinomycin induces the cancer stem cells into normal cells, dormant cells, and mature cancer cells. Besides, the results indicate that the gatekeeper is related to the inhibition of the protein kinase C (PKC) α signaling pathway. The differentiated normal or dormant cells are incorporated into normal tissue, whereas the rest are killed by chemotherapy. The findings would offer the evidence for plastic differentiation of cancer stem cells and propose a novel strategy for cancer therapy.

Phytol Down-Regulates Expression of Some Cancer Stem Cell Markers and Decreases Side Population Proportion in Human Embryonic Carcinoma NCCIT Cells

Cancer stem cells (CSCs), a subgroup of cancer cells, have self-renewal capacity and differentiation potential and drive tumor growth. CSCs are highly-resistant to conventional chemo-radio therapy. Phytochemicals were shown to be able to eliminate CSCs. Phytol is a diterpene alcohol with demonstrated anticancer effects. The current study compared the effect of phytol with retinoic acid (RA) as a well-known inducers of CSC differentiation and cisplatin, a common chemotherapy drug, on CSC markers in human embryonic carcinoma NCCIT cells. NCCIT cells were exposed to 10 mM RA for 14 day to induce differentiation. Moreover, NCCIT cells were treated with IC50 dose of cisplatin (12 µM) and phytol (40 µM) for 7 day. Real-time PCR showed that phytol was more effective that RA and cisplatin in down-regulating the CSC markers OCT4, NANOG, SOX2, ALDH1, ABCB1, CD44 and CD133. Percentage of SP (13%) and ABCB1+ (0.34%) in NCCIT cells decreased to 7% and 0.1% respectively after treatment with phytol. A very small proportion of NCCIT cells were positive for CD44 (0.2%) and CD133 (0.48%) and this fraction did not change significantly after treatment with three agents. In conclusion, phytol has the greatest inhibitory effect on CSC population and markers than RA and cisplatin.

Differentiation of Cancer Stem Cells Halts Protein and rRNA Synthesis

Colorectal cancer cells lost biosynthetic capabilities in an irreversible differentiation process.

Blood and Cancer: Cancer Stem Cells as Origin of Hematopoietic Cells in Solid Tumor Microenvironments.

The concepts of hematopoiesis and the generation of blood and immune cells from hematopoietic stem cells are some steady concepts in the field of hematology. However, the knowledge of hematopoietic cells arising from solid tumor cancer stem cells is novel. In the solid tumor microenvironment, hematopoietic cells play pivotal roles in tumor growth and progression. Recent studies have reported that solid tumor cancer cells or cancer stem cells could differentiate into hematopoietic cells. Here, we discuss efforts and research that focused on the presence of hematopoietic cells in tumor microenvironments. We also discuss hematopoiesis from solid tumor cancer stem cells and clarify the notion of differentiation of solid tumor cancer stem cells into non-cancer hematopoietic stem cells.

Relation between Immune cell response and stemness genes expression in breast cancer; A new approach in NANOG gene and Let7-a expression in breast cancer cell lines

Introduction: Failure and recurrence in breast cancer treatment cause a great obstacle in cancer therapy and identification of cell population named cancer stem cells (CSCs) in the tumor can be led us to define it as target in novel therapeutic strategy. Objectives: The aim of this study is the finding of correlation between stemness and metastatic characteristic, also knowing CSCs as a potential target of therapy because of its developmental behavior and similarities with normal stem cells. Materials and Methods: Here, we focus on the expression of NANOG in breast CSCs, a key molecule in the physiological process of stem cells and the Let-7a that is involved in the differentiation of the cells. Results: In this work, we found that NANOG was highly expressed in SKBR3 and down-regulation of let-7a, as a differentiation miRNA, was found in MDA-MB-468 cells. Conclusion: It will be critical for the developing of effective anti-tumor drugs, utilizing mentioned concepts. Inhibition of NANOG in combination with Let-7a up-regulation can help to decrease the stemness and increase the differentiation of CSCs. The decrease of stemness and increase of differentiation initiate the apoptotic process. So, modification in the mechanism of apoptosis beside anti-cancer drugs provide a good preclinical study goal. However, in order to these drugs become clinical, the problems of their side effects and toxicity must be solved. Differentiation of CSCs provides an optimal condition to activity of immune cells which never let them escape from immune cells by alteration of immunogenicity.

Hsa_circ_0068307 mediates bladder cancer stem cell-like properties via miR-147/c-Myc axis regulation

BackgroundCircular RNAs (circRNAs) play an essential role in the regulation of gene expression. However, the underlying mechanisms remain unknown. This study aimed to evaluate the role of hsa_circ_0068307 in bladder cancer (BCa).MethodsRt-qPCR was used to detect hsa_circ_0068307 expression in BCa cell lines. The CCK8, colony formation, and Transwell assays were used to evaluate the effect of hsa_circ_0068307 on BCa cell migration and proliferation. Bioinformatics and luciferase reporter experiments were used to study the regulatory mechanism. Nude mouse xenografts were generated to examine the effect of hsa_circ_0068307 on tumor growth.ResultsThe results showed that hsa_circ_0068307 was upregulated in BCa cell lines. Downregulation of hsa_circ_0068307 suppressed cell migration and proliferation in T24 and UMUC3 cells. Hsa_circ_0068307 silencing suppressed cancer stem cell differentiation by upregulating miR-147 expression. Upregulation of miR-147 suppressed c-Myc expression, which is involved in cancer stem cell differentiation. Luciferase reporter assays confirmed that hsa_circ_0068307 upregulated c-Myc expression by targeting miR-147. In vivo studies showed that hsa_circ_0068307 knockdown suppressed T24 tumor growth.ConclusionsThese data indicate that downregulation of hsa_circ_0068307 reversed the stem cell-like properties of human bladder cancer through the regulation of the miR-147/c-Myc axis.

The effects of microgravity on differentiation and cell growth in stem cells and cancer stem cells.

A spaceflight has enormous influence on the health of space voyagers due to the combined effects of microgravity and cosmic radiation. Known effects of microgravity (μg) on cells are changes in differentiation and growth. Considering the commercialization of spaceflight, future space exploration, and long‐term manned flights, research focusing on differentiation and growth of stem cells and cancer cells exposed to real (r‐) and simulated (s‐) μg is of high interest for regenerative medicine and cancer research. In this review, we focus on platforms to study r‐ and s‐μg as well as the impact of μg on cancer stem cells in the field of gastrointestinal cancer, lung cancer, and osteosarcoma. Moreover, we review the current knowledge of different types of stem cells exposed to μg conditions with regard to differentiation and engineering of cartilage, bone, vasculature, heart, skin, and liver constructs.

CCND1 silencing suppresses liver cancer stem cell differentiation and overcomes 5-Fluorouracil resistance in hepatocellular carcinoma

ObjectiveChemoresistance is one of the major barriers in chemotherapy-based hepatocellular carcinoma (HCC) intervention. 5-Fluorouracil (5-Fu) is a widely used as an anticancer drug. Liver cancer stem cells (LCSCs) are considered the origin of tumor recurrence and resistance. CCND1 (Cyclin D1) plays an important role in tumorigenesis and metastasis in multiple cancers including HCC. Herein, this study was designed to explore the role of CCND1 in regulating LCSCs differentiation and 5-Fu resistance in HCC cells. MethodsThe CCND1 mRNA level was examined by qRT-PCR. The protein levels of γ-H2AX (a DNA damage marker) and RAD51 (a DNA repair protein) were examined by Western blot. CD133 was used as a LCSC marker and CD133+ cell percentage in HCC cells was detected by flow cytometry. ResultsCCND1 silencing decreased CD133+ cell percentage in HepG2 and SMMC-7721 cells. Furthermore, CCND1 silencing significantly increased protein level of γ-H2AX and decreased that of RAD51 under 5-Fu exposure. Moreover, CCND1 silencing enhanced the sensitivity of HepG2 and SMMC-7721 cells to 5-Fu, which was effectively abrogated by RAD51 upregulation. ConclusionCollectively, CCND1 silencing suppresses LCSCs differentiation and overcomes 5-Fu resistance in HCC.

Graphene-Induced Transdifferentiation of Cancer Stem Cells as a Therapeutic Strategy against Glioblastoma.

Glioblastoma (GBM) is an extremely malignant tumor of the central nervous system, characterized by low response to treatments and reoccurrence. This therapeutic resistance is believed to arise mostly from the presence of a subpopulation of tumorigenic stem cells, known as cancer stem cells (CSCs). In addition, the surrounding microenvironment is known to maintain CSCs, thus supporting tumor development and aggressiveness. This review focuses on a therapeutic strategy involving the stem cell trans-differentiating ability of graphene and its derivatives. Graphene distinguishes itself from other carbon-based nanomaterials due to an array of properties that makes it suitable for many purposes, from bioengineering to biomedical applications. Studies have shown that graphene is able to promote and direct the differentiation of CSCs. In addition, potential usage of graphene in GBM treatment represents a challenge in respect to its administration method. The present review also provides a general outlook of the potential side effects (e.g., cell toxicity) that graphene could have. Overall, this report discusses certain graphene-based therapeutic strategies targeting CSCs, which can be considered as prospective effective GBM treatments.

Revisiting Cancer Stem Cells as the Origin of Cancer-Associated Cells in the Tumor Microenvironment: A Hypothetical View from the Potential of iPSCs.

The tumor microenvironment (TME) has an essential role in tumor initiation and development. Tumor cells are considered to actively create their microenvironment during tumorigenesis and tumor development. The TME contains multiple types of stromal cells, cancer-associated fibroblasts (CAFs), Tumor endothelial cells (TECs), tumor-associated adipocytes (TAAs), tumor-associated macrophages (TAMs) and others. These cells work together and with the extracellular matrix (ECM) and many other factors to coordinately contribute to tumor growth and maintenance. Although the types and functions of TME cells are well understood, the origin of these cells is still obscure. Many scientists have tried to demonstrate the origin of these cells. Some researchers postulated that TME cells originated from surrounding normal tissues, and others demonstrated that the origin is cancer cells. Recent evidence demonstrates that cancer stem cells (CSCs) have differentiation abilities to generate the original lineage cells for promoting tumor growth and metastasis. The differentiation of CSCs into tumor stromal cells provides a new dimension that explains tumor heterogeneity. Using induced pluripotent stem cells (iPSCs), our group postulates that CSCs could be one of the key sources of CAFs, TECs, TAAs, and TAMs as well as the descendants, which support the self-renewal potential of the cells and exhibit heterogeneity. In this review, we summarize TME components, their interactions within the TME and their insight into cancer therapy. Especially, we focus on the TME cells and their possible origin and also discuss the multi-lineage differentiation potentials of CSCs exploiting iPSCs to create a society of cells in cancer tissues including TME.

Inhibition of scutellarin on differentiation of colonic cancer stem cells via hedgehog signaling pathway

The objective of this study was to investigate the inhibitory effect of scutellarin on the differentiation of colonic cancer stem cells in vitro and in vivo and to explore its underlying hedgehog signaling-based mechanism. The effect of scutellarin on the growth in vitro of HT-29 cells-derived cancer stem-like cells(HT-29 CSC) was observed with 3 D cell culture. The effect of scutellarin on the transformation of HT-29 CSC cells was assessed by soft agar colony formation assay. Fetal calf serum was used to induce differentiation of stem cells and observe the effect of scutellarin on HT-29 CSC cells differentiation in vitro. The effects of scutellarin on mRNA expressions of Lgr5, c-Myc, CK20 and Nanog in HT-29 CSC cells were determined by quantitative Real-time polymerase chain reaction(qRT-PCR). The effects of scutellarin on protein expressions of c-Myc, Gli1 and Lgr5 in HT-29 CSC cells were examined by Western blot. After subcutaneous implantation of HT-29 CSC cells in nude mice, the effect of scutellarin on the mouse body weight and the growth of HT-29 CSC-derived tumor were explored. qRT-PCR was used for evaluating the effect of scutellarin on mRNA levels of CD133, Lgr5, Gli1, Ptch1, c-Myc, Ki-67, CK20 and Nanog in tumor. Western blot and immunohistochemistry analysis were used to detect the effect of scutellarin on protein expressions of c-Myc, Gli1, Lgr5, CD133 and Ki-67 in tumor. The in vitro experiments showed that scutellarin inhibited the growth, transformation and differentiation of HT-29 CSC cells, significantly down-regulated the mRNA levels of Lgr5, c-Myc, CK20 and Nanog in HT-29 CSC cells as well as the protein expression levels of c-Myc, Gli1 and Lgr5 in HT-29 CSC cells. Additionally, animal experiments showed that scutellarin significantly inhibited the growth of subcutaneous xenografts in nude mice, and down-regulated the mRNA expressions of CD133, Lgr5, Gli1, Ptch1, c-Myc, Ki-67, CK20 and Nanog as well as the protein levels of c-Myc, Gli1, Lgr5, CD133 and Ki-67 of xenografts in nude mice. Taken together, scutellarin could inhibit the differentiation of colo-nic cancer stem cells in vitro and in vivo, potentially by down regulation of hedgehog signaling pathway activity.

Ubiquitination in cancer stem cell: roles and targeted cancer therapy

Cancer stem cells (CSCs) are a small subset of stem-like cells inside tumors, which possess abilities of unlimited self-renewal, differentiation and proliferation. Extensive studies have suggested that CSCs are one of the major drivers of tumor initiation, metastasis, relapse and therapeutic resistance. Several regulatory networks including transcriptional programs and various signaling pathways tightly control the stemness, proliferation and differentiation of CSCs. Emerging evidence has indicated that post-translational modifications, especially ubiquitination, play a critical role in maintenance of CSC properties. In this review, we summarize current understandings on E3 ubiquitin ligase-mediated regulation of transcription factors and key signaling pathways involved in the regulation of CSCs, and discuss the strategy to target CSCs and E3 ubiquitin ligases for combating cancers.

CD147 Promotes Cell Small Extracellular Vesicles Release during Colon Cancer Stem Cells Differentiation and Triggers Cellular Changes in Recipient Cells.

Cancer cells secrete small extracellular vesicles (sEVs) that are involved in the remodeling of tumor microenvironment (TME) and can promote tumor progression. The role of sEVs and their molecular key players in colon cancer stem cells differentiation are poorly understood. This study aimed to analyze the role and content of sEVs released during the differentiation of colorectal cancer stem cells. Here we show that sEVs secretion during colon cancer stem cells differentiation is partially controlled by CD147, a well-known player involved in colon cancer tumorigenesis. CD147 + sEVs activate a signaling cascade in recipient cells inducing molecular invasive features in colon cancer cells. CD147 knockdown as well as anti-CD147 antibodies impaired sEVs release and downstream effects on recipient cells and blocking multivesicular body maturation prevented sEVs release during the differentiation. Our findings reveal a functional role of CD147 in promoting sEVs release during the differentiation of colon cancer stem cells and in triggering cellular changes in recipient cells.

Targeting LA7 breast cancer stem cells of rat through repressing the genes of stemness-related transcription factors using three different biological fluids

Down-regulation of stemness genes expression is important in differentiation therapy against cancer stem cells (CSCs). The aim of this study was to evaluate the Oct4 , Sox2, Nanog, and C-myc expression in rat breast cancer stem cells (LA7) which treated with human ovarian follicular fluid (FF), replicative senescent fibroblast culture supernatant (P14), and 16 h serum starved fibroblast supernatant (16 h-SFS). The cells were exposed to these biological fluids for 24 h, 72 h, and 7 days. Stem-loop RT-qPCR assay was used to quantify the expression of above mentioned genes. Results showed that FF had the least cytotoxic effect on the LA7 cells. Except for Nanog gene, exposure of LA7 cell line to 16 h-SFS and P14 decreased significantly expression of the three other genes after 24 h (P < 0.05). Nanog and Sox2 genes expression was also decreased in LA7 cells which have been already treated with FF for 24 h. Moreover, compared to the control solution, the expression of Oct4 increased significantly after 7 days exposure to FF (P < 0.05). Annexin V-PE /7-AAD-, acridine orange/ethidium bromide staining and doubling time assays revealed apoptosis and necrosis induction by these biological fluids in LA7 cells. Moreover, in an in vitro model of metastasis assay, i.e., scratch test, these fluids exhibited anti-LA7 migration activity which culminated in 16 h-SFS treated cells. Generally, this study showed that FF, 16 h-SFS, and P14 have positive effects on down-regulation of Nanog, Oct4, Sox2 and C-myc expression, and consequently can increase the differentiation of breast cancer stem cells. For the first time, this study provided some evidence indicating that some biological fluids have potential to differentiate the CSCs, show anti- survival, growth-, and cell migration activity.

Suppressing the metastatic properties of the breast cancer cells using STAT3 decoy oligodeoxynucleotides: A promising approach for eradication of cancer cells by differentiation therapy.

Due to the presence of cancer stem cells (CSCs), breast cancer often relapsed after conventional therapies. Strategies that induce differentiation of CSCs will be helpful in eradication of tumor cells, so we designed an oligodeoxynucleotide (ODNs) for targeting of signal transducer and activator of transcription 3 (STAT3) transcription factor which is involved in stemness, and constitutively activated in triple-negative breast cancer. Molecular docking and electrophoretic mobility shift assay analysis showed that decoy ODN bound specifically to the DNA binding site of STAT3 protein. The prevalent uptake of Cy3-labeled ODNs is in the cytoplasm and the nucleus of MDA-MB-231 treated cells. STAT3 decoy ODNs treatment showed cell growth inhibition by decreasing cell viability (17%), increasing the percentage of arrested cells in G0/G1 phases (18%), and triggering apoptosis (29%). Migration and invasion potential decreased from 10.77 to 6.76 µm/hr, by wound closure rate, and migrated/invaded percentage by 26.4% and 15.4% in the transwell assays, respectively. CD44 protein expression level on the cell surface also decreased, while CD24 increased. Mammosphere formation efficiency reduced in terms of tumorsphere size by 47%, while the required time increased. Cells morphology was changed, and lipid droplets were accumulated in the cytoplasm compared to the control and scrambled groups, in all assays (repeated triplicate). Furthermore, the gene expression of all downstream targets significantly decreased owing to suppressing the STAT3 transcription factor. Overall, the results confirmed the antitumor effects of STAT3 decoy in MDA-MB-231 cells. Thus, it seems that STAT3 decoy ODNs might be considered as an auxiliary tool for breast cancer eradicating by the differentiation therapy approach.

Combination Therapy with Vitamin C Could Eradicate Cancer Stem Cells.

Cancer remains one of the most feared and dreaded diseases in this era of modern medicine, claiming the lives of many, and affecting the quality of life of several others around the globe despite major advances in the diagnosis, treatment, palliative care and the immense resources invested into cancer research. While research in cancer has largely focused on the neoplasm/tumor and the cancerous cells that make up the tumor, more recently, the existence, proliferation, differentiation, migration and invasion of cancer stem cells (CSCs) and the role that CSCs play in tumor initiation, progression, metastasis, drug resistance and relapse/recurrence of the disease has gained widespread interest in cancer research. Although the conventional therapeutic approaches such as surgery, chemotherapy and radiation therapy are effective cancer treatments, very often these treatment modalities fail to target the CSCs, which then later become the source of disease recurrence. A majority of the anti-cancer agents target rapidly dividing cancer cells and normal cells and hence, have side effects that are not expected. Targeting CSCs remains a challenge due to their deviant nature with a low proliferation rate and increased drug resistance mechanism. Ascorbic acid/Vitamin C (Vit.C), a potent antioxidant, is a cofactor for several biosynthetic and gene regulatory enzymes and a vital contributor to immune defense of the body, and was found to be deficient in patients with advanced stages of cancer. Vit.C has gained importance in the treatment of cancer due to its ability to modulate the redox status of the cell and influence epigenetic modifications and significant roles in HIF1α signaling. Studies have reported that intravenous administration of Vit.C at pharmacological doses selectively kills tumor cells and targets CSCs when administered along with chemotherapeutic drugs. In the current article, we provide an in-depth review of how Vit.C plays an important role in targeting CSCs and its possible use as an adjuvant, neoadjuvant or co-treatment in the treatment of cancers.

YB-1 interplays with ERα to regulate the stemness and differentiation of ER-positive breast cancer stem cells.

Background: Some stemness-associated transcription factors consistently play essential roles in the maintenance of pluripotency or induce the differentiation of cancer stem cells (CSCs). However, the regulatory mechanism of CSC stemness mediated by transcription factors has not been extensively explored. Here, we show that two transcription factors (YB-1 and ERα), which are simultaneously highly expressed in estrogen receptor (ER)-positive CSCs, interact with each other to regulate the stemness and differentiation of ER-positive CSCs.Methods: The expression of YB-1 was examined in ER-positive CSCs and patient specimens. Western blot, real-time PCR, cell viability analysis, tumorsphere formation assay and subcutaneous tumorigenesis assays were used to study the stemness functions of YB-1 and ERα in CSCs. The relationship between YB-1 and ERα in cells was studied by promoter activity analysis, the electrophoretic mobility shift assay (EMSA) and the Co-IP assay. The mechanisms and functional significance of YB-1 in the sensitivity of CSCs to tamoxifen were further investigated with both in vitro and in vivo models.Results: YB-1 was aberrantly upregulated in the cancerous tissue of ER-positive breast cancer patients and in CSCs. Knockdown of YB-1 in ER-positive CSCs significantly inhibited cell stemness and induced differentiation, and the expression of YB-1 could be regulated by estrogen signaling and ERα in ER-positive breast CSCs. The Co-IP results showed that YB-1 interacted directly with ERα specifically in ER-positive non-CSCs and that YB-1 induced ERα degradation by ubiquitination via direct interaction in differentiated cells. Cell differentiation induced by FBS could inhibit YB-1 phosphorylation and promote YB-1 protein transfer from the nucleus to the cytoplasm. Moreover, cell differentiation induced by targeting inhibited the expression of YB-1 in ER-positive CSCs, which increased the sensitivity of cells to tamoxifen in vitro and in vivo.Conclusion: The ERα/YB-1 axis has an important role in the regulation of ER-positive breast cancer stemness. The dephosphorylation of YB-1 and the interaction between YB-1 and ERα may be the switch that initiates the differentiation of ER-positive CSCs. Targeting YB-1 to sensitize ER-positive CSCs to antiestrogen therapy might represent a new therapeutic strategy that warrants further exploration.

Multiple Defects of Natural Killer Cells in Cancer Patients: Anarchy, Dysregulated Systemic Immunity, and Immunosuppression in Metastatic Cancer.

We have previously demonstrated that natural killer (NK) cells are the main immune effectors that can mediate selection and differentiation of different cancer stem cells and undifferentiated tumors via lysis and secreted or membrane-bound interferon-γ and tumor necrosis factor-α, respectively. This leads to growth inhibition and tumor metastasis curtailment. In this review, we present an overview of our findings on NK cell biology and its significance in selection and differentiation of stem-like tumors using in vitro and in vivo studies conducted in nonobese diabetic/severe combined immunodeficiency (scid)/interleukin-Rγ--, humanized-bone-marrow/liver/thymus (hu-BLT) mice, and those of human cancer patients. Moreover, we present recent advances in NK cell expansion and therapeutic delivery and discuss the superiority of allogeneic supercharged NK cells over their autologous counterparts for cancer treatment. We review potential loss of NK cell numbers and function at neoplastic and preneoplastic stages of tumorigenesis as a potential mechanism for pancreatic cancer induction and progression. We believe that NK cells should be placed highly in the armamentarium of tumor immunotherapy due to their indispensable role in targeting cancer stem-like/poorly differentiated tumors and a variety of other key NK cell functions that are discussed in this report, including their role in CD8+ T-cell expansion and targeting gene knockout or dedifferentiated tumors. The combination of allogeneic supercharged NK cells and other immunotherapeutic strategies such as oncolytic viruses, antibody-dependent cellular cytotoxicity-inducing antibodies, checkpoint inhibitors, chimeric antigen receptor (CAR)-T cells and CAR-NK cells, chemotherapeutics, and radiotherapeutic strategies can be used for optimal eradication of tumors.