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Abstract Background Hypoxia-activated prodrug (HAP) is a promising candidate for highly tumor-specific chemotherapy. However, the oxygenation heterogeneity and dense extracellular matrix (ECM) of tumor, as well as the potential resistance to chemotherapy, have severely impeded the resulting overall efficacy of HAP. Results A HAP potentiating strategy is proposed based on ultrasound responsive nanodroplets (PTP@PLGA), which is composed of protoporphyrin (PpIX), perfluoropropane (PFP) and a typical HAP, tirapazamine (TPZ). The intense vaporization of PFP upon ultrasound irradiation can magnify the sonomechanical effect, which loosens the ECM to promote the penetration of TPZ into the deep hypoxic region. Meanwhile, the PpIX enabled sonodynamic effect can further reduce the oxygen level, thus activating the TPZ in the relatively normoxic region as well. Surprisingly, abovementioned ultrasound effect also results in the downregulation of the stemness of cancer cells, which is highly associated with drug-refractoriness. Conclusions This work manifests an ideal example of ultrasound-based nanotechnology for potentiating HAP and also reveals the potential acoustic effect of intervening cancer stem-like cells. Graphical Abstract

Background: Hypoxia-activated prodrug (HAP) is a promising candidate for highly tumor-specific chemotherapy. However, the oxygenation heterogeneity and dense extracellular matrix (ECM) of tumor, as well as the potential resistance to chemotherapy, have severely impeded the resulting overall efficacy of HAP. Results: A HAP potentiating strategy is proposed based on ultrasound responsive nanodroplets (PTP@PLGA), which is composed of protoporphyrin (PpIX), perfluoropropane (PFP) and a typical HAP, tirapazamine (TPZ). The intense vaporization of PFP upon ultrasound irradiation can magnify the sonomechanical effect, which loosens the ECM to promote the penetration of TPZ into the deep hypoxic region. Meanwhile, the PpIX enabled sonodynamic effect can further reduce the oxygen level, thus activating the TPZ in the relatively normoxic region as well. Surprisingly, abovementioned ultrasound effect also results in the downregulation of the stemness of cancer cells, which is highly associated with drug-refractoriness. Conclusions: This work manifests an ideal example of ultrasound-based nanotechnology for potentiating HAP and also reveals the potential acoustic effect of intervening cancer stem-like cells. [ABSTRACT FROM AUTHOR]

Many patients diagnosed with acute myeloid leukemia (AML) relapse within two years of the initial remission. The biology of AML relapse is incompletely understood, although cancer stem-like (CSL) cells have been hypothesized to be important. To test this hypothesis, we employed SORE6, a reporter designed to detect the transcriptional activity of the embryonic stem cell proteins Oct4 and Sox2, to identify/purify CSL cells in two FLT3-mutated AML cell lines. Both cell lines contained ~10% of SORE6+ cells in the steady state. Compared to SORE6− cells, SORE6+ cells exhibited more characteristics of CSL cells, with significantly higher chemoresistance and rates of spheroid formation. SORE6+ cells had substantially higher expression of Myc and FLT3 proteins, which are drivers of SORE6 activity. Using a mixture of SORE6−/SORE6+ cells that were molecularly barcoded, we generated an in vitro study model for AML relapse. Specifically, after 'in vitro remission' induced by Ara-C, both cell lines regenerated after 13 ± 3 days. Barcode analysis revealed that most of the regenerated cells were derived from the original SORE6+ cells. Regenerated cells exhibited more CSL features than did the original SORE6+ cells, even though a proportion of them lost SORE6 activity. In bone marrow samples from a patient cohort, we found that relapsed blasts expressed significantly higher levels of Myc, a surrogate marker of SORE6 activity, compared to pre-treatment blasts. To conclude, using our in vitro model, we have provided evidence that CSL cells contribute to AML relapse. [ABSTRACT FROM AUTHOR]

Drug resistance presents one of the major causes for the failure of cancer chemotherapy. Cancer stem-like cells (CSCs), a population of self-renewal cells with high tumorigenicity and innate chemoresistance, can survive conventional chemotherapy and generate increased resistance. Here, we develop a lipid-polymer hybrid nanoparticle for co-delivery and cell-distinct release of the differentiation-inducing agent, all-trans retinoic acid and the chemotherapeutic drug, doxorubicin to overcome the CSC-associated chemoresistance. The hybrid nanoparticles achieve differential release of the combined drugs in the CSCs and bulk tumor cells by responding to their specific intracellular signal variation. In the hypoxic CSCs, ATRA is released to induce differentiation of the CSCs, and in the differentiating CSCs with decreased chemoresistance, DOX is released upon elevation of reactive oxygen species to cause subsequent cell death. In the bulk tumor cells, the drugs are released synchronously upon the hypoxic and oxidative conditions to exert potent anticancer effect. This cell-distinct drug release enhances the synergistic therapeutic efficacy of ATRA and DOX with different anticancer mechanism. We show that treatment with the hybrid nanoparticle efficiently inhibit the tumor growth and metastasis of the CSC-enriched triple negative breast cancer in the mouse models.

Abstract Background Maintenance of cancer stem‐like cell (CSC) stemness supported by aberrantly regulated cancer cell metabolism is critical for CSC self‐renewal and tumor progression. As a key glycolytic enzyme, hexokinase 2 (HK2) plays an instrumental role in aerobic glycolysis and tumor progression. However, whether HK2 directly contribute to CSC stemness maintenance in small cell lung cancer (SCLC) is largely unclear. In this study, we aimed to investgate whether HK2 independent of its glycolytic activity is directly involved in stemness maintenance of CSC in SCLC. Methods Immunoblotting analyses were conducted to determine the expression of HK2 in SCLC CSCs and their differentiated counterparts. CSC‐like properties and tumorigenesis of SCLC cells with or without HK2 depletion or overexpression were examined by sphere formation assay and xenograft mouse model. Immunoprecipitation and mass spectrometry analyses were performed to identify the binding proteins of CD133. The expression levels of CD133‐associated and CSC‐relevant proteins were evaluated by immunoblotting, immunoprecipitation, immunofluorescence, and immunohistochemistry assay. RNA expression levels of Nanog, POU5F1, Lin28, HK2, Prominin‐1 were analyzed through quantitative reverse transcription PCR. Polyubiquitination of CD133 was examined by in vitro or in vivo ubiquitination assay. CD133+ cells were sorted by flow cytometry using an anti‐CD133 antibody. Results We demonstrated that HK2 expression was much higher in CSCs of SCLC than in their differentiated counterparts. HK2 depletion inhibited CSC stemness and promoted CSC differentiation. Mechanistically, non‐mitochondrial HK2 directly interacted with CD133 and enhanced CD133 expression without affecting CD133 mRNA levels. The interaction of HK2 and CD133 promoted the binding of the deubiquitinase ubiquitin‐specific protease 11 (USP11) to CD133, thereby inhibiting CD133 polyubiquitylation and degradation. HK2‐mediated upregulation of CD133 expression enhanced the expression of cell renewal regulators, SCLC cell stemness, and tumor growth in mice. In addition, HK2 expression was positively correlated with CD133 expression in human SCLC specimens, and their expression levels were associated with poor prognosis of SCLC patients. Conclusions These results revealed a critical non‐metabolic function of HK2 in promotion of cancer cell stemness. Our findings provided new insights into the multifaceted roles of HK2 in tumor development.

Cancer stem‐like cells (CSLC) are considered a major contributor to the development and progression of hepatocellular carcinoma (HCC). Previous studies indicated that CSLC are characterized by resistance to ferroptosis, a type of lipid peroxidation‐dependent cell death. Here, we identified a set of ferroptosis‐related stemness genes (FRSG) and found that these genes may be involved in immune infiltration in HCC. A four‐FRSG (CDKN2A, GABARAPL1, HRAS, RPL8) risk model with prognostic prediction was constructed by a Cox analysis in HCC. Among these four genes, GABARAPL1 was downregulated in HCC tumor‐repopulating cells (TRC; a type of CSLC). Its downregulation decreased the sensitivity of HCC TRC to erastin‐ or sorafenib‐triggered ferroptosis. Together, we uncovered a molecular mechanism via which CSLC could achieve tolerance to ferroptosis. Further studies may provide potential therapeutic strategies targeting CSLC in HCC.

Drug resistance presents one of the major causes for the failure of cancer chemotherapy. Cancer stem-like cells (CSCs), a population of self-renewal cells with high tumorigenicity and innate chemoresistance, can survive conventional chemotherapy and generate increased resistance. Here, we develop a lipid-polymer hybrid nanoparticle for co-delivery and cell-distinct release of the differentiation-inducing agent, all- trans retinoic acid and the chemotherapeutic drug, doxorubicin to overcome the CSC-associated chemoresistance. The hybrid nanoparticles achieve differential release of the combined drugs in the CSCs and bulk tumor cells by responding to their specific intracellular signal variation. In the hypoxic CSCs, ATRA is released to induce differentiation of the CSCs, and in the differentiating CSCs with decreased chemoresistance, DOX is released upon elevation of reactive oxygen species to cause subsequent cell death. In the bulk tumor cells, the drugs are released synchronously upon the hypoxic and oxidative conditions to exert potent anticancer effect. This cell-distinct drug release enhances the synergistic therapeutic efficacy of ATRA and DOX with different anticancer mechanism. We show that treatment with the hybrid nanoparticle efficiently inhibit the tumor growth and metastasis of the CSC-enriched triple negative breast cancer in the mouse models. This study developed an easy-to-fabricate lipid-polymer hybrid nanoparticle for co-delivery and cell-distinct release of the differentiation-inducing agent ATRA, and the chemotherapeutic drug DOX, to overcome the CSC-associated chemoresistance. [Display omitted] [ABSTRACT FROM AUTHOR]

While previous studies have identified cancer stem‐like cells (CSCs) as a crucial driver for chemoresistance and tumor recurrence, the underlying mechanisms for populating the CSC pool remain unclear. Here, we identify hypermitophagy as a feature of human lung CSCs, promoting metabolic adaption via the Notch1‐AMPK axis to drive CSC expansion. Specifically, mitophagy is highly active in CSCs, resulting in increased mitochondrial DNA (mtDNA) content in the lysosome. Lysosomal mtDNA acts as an endogenous ligand for Toll‐like receptor 9 (TLR9) that promotes Notch1 activity. Notch1 interacts with AMPK to drive lysosomal AMPK activation by inducing metabolic stress and LKB1 phosphorylation. This TLR9‐Notch1‐AMPK axis supports mitochondrial metabolism to fuel CSC expansion. In patient‐derived xenograft chimeras, targeting mitophagy and TLR9‐dependent Notch1‐AMPK pathway restricts tumor growth and CSC expansion. Taken together, mitochondrial hemostasis is interlinked with innate immune sensing and Notch1‐AMPK activity to increase the CSC pool of human lung cancer. Synopsis: Lung cancer stem‐like cells show high levels of mitophagy, resulting in lysosomal mtDNA accumulation that activates TLR9 and Notch1‐AMPK signaling. The TLR9‐Notch1‐AMPK pathway promotes CSC expansion and can be therapeutically targeted. CSCs show mitophagic hyperactivity, resulting in the accumulation of mtDNA in lysosomes.Lysosomal mtDNA activates TLR9 and drives the expansion of lung CSCs.TLR9 interacts with Notch1, triggering Notch1 activation and subsequent AMPK phosphorylation.Blocking the TLR9‐dependent Notch1‐AMPK pathway inhibits tumor outgrowth and reduces lung CSCs. [ABSTRACT FROM AUTHOR]

Chemotherapy remains a major therapeutic approach to cancer treatment. However, its effectiveness can be compromised by the heterogeneity of a solid tumor, in which different cancer cell populations display varied responses to chemotherapy. Such an intratumor heterogeneous structure is maintained by the cancer stem-like cells (CSCs) with inherent capacities for self-renewal and differentiation, giving rise to diverse cell populations. To address this, we proposed a combinational strategy in which tumor lesion-targeted Notch signaling regulation was achieved to disrupt CSC-mediated cancer heterogeneity, thereby sensitizing solid tumors toward paclitaxel (PTX). Specifically, gamma-secretase inhibitor LY-411,575 was co-delivered with PTX using a near-infrared (NIR) light-controlled drug delivery system to realize targeted ablation of both differentiated cancer cells and undifferentiated CSCs. By enabling precise regulation of the Notch pathway at the tumor site through NIR light, we observed significantly elevated efficacy of chemotherapy and notable prevention of postsurgical tumor relapse while minimizing systemic side effects. The devised strategy shows promise in addressing the nonspecific inhibition of stemness across various organs, a challenge that hampers the clinical translation of gamma-secretase inhibitors in cancer therapy.

There is increasing evidence that cytoskeleton remodeling is involved in cancer progression. Wiskott-Aldrich syndrome protein (WASP) family represents a key regulator of actin cytoskeleton remodeling. However, the underlying mechanism of the WASP family in cancer progression remains elusive. Here, we studied the role of WASP and SCAR Homolog (WASH), a recently identified WASP family member, in human esophageal squamous cell carcinoma (ESCC). Using three human ESCC cell lines, we found that WASH expression was significantly elevated in cancer stem-like cells enriched by sphere formation assay. WASH knockdown decreased the sphere-forming capacity of esophageal cancer cells whereas WASH over-expression exhibited the opposite effect. Mechanistically, we identified interleukin-8 (IL-8) as a key downstream target of WASH. IL-8 knockdown completely attenuated tumor sphere formation induced by WASH overexpression. WASH knockdown also delayed the growth of human ESCC xenografts in BALB/c nude mice. Importantly, high WASH levels were associated with poor clinical prognosis in a total of 145 human ESCC tissues. Collectively, our results suggest an essential role of the WASH/IL-8 pathway in human ESCC by maintaining the stemness of cancer cells. Hence, targeting this pathway might represent a promising strategy to control human esophageal carcinoma.

HYD-PEP06, an endostatin-modified polypeptide, has been shown to produce effective anti-colorectal carcinoma effects through inhibiting epithelial–mesenchymal transition (EMT). However, whether HYD-PEP06 has similar suppressive effect on hepatocellular carcinoma (HCC) remained unknown. In this study, HYD-PEP06 inhibited metastasis and EMT but not proliferation in vitro. Cignal finder pathway reporter array and Western blot analysis revealed that HYD-PEP06 suppressed HCCLM3 cell metastasis and EMT by inhibiting the PI3K/AKT pathway. Moreover, HYD-PEP06 exerted anti-metastasis effects in HepG2 cancer stem-like cells (CSCs) via suppressing the WNT/β-catenin signaling pathway. Finally, in HCCLM3 tumor-bearing BALB/c nu/nu nude mice, HYD-PEP06 substantially suppressed tumor growth, lung metastasis and HCC progress. Our results suggest that HYD-PEP06 inhibits the metastasis and EMT of HCC and CSCs as well, and thus has the potential as an agent for HCC treatment.

Cancer stem-like cells (CSCs) have a well-established role in mediating tumor relapse and resistance towards chemotherapy and radiation therapy. Photothermal therapy (PTT) is an efficient therapeutic strategy that uses light and photothermal agents to generate hyperthermia in tumors and kill cancer cells. However, due to the heterogeneity and drug resistance of CSCs, some of them may survive from PTT and cause recurrence and metastasis of tumors. In the study, we present a sequential dual-wavelength light-controlled drug delivery strategy, which combines 656 nm light-triggered drug release to inhibit cancer stemness, followed by 808 nm light-activated PTT to eradicate bulk tumors. The first light irradiation induces the release of γ-secretase inhibitor MK-0752 to deactivate Notch pathway, which is a key regulator of CSCs. Subsequently, the second light irradiation triggers hyperthermia to effectively kill tumor cells. Our findings demonstrate that inhibiting cancer stemness increases tumor sensitivity to PTT, resulting in effective growth inhibition of primary tumors with repressed tumorgenicity. This innovative dual-wavelength strategy holds promise for enhancing the efficacy of PTT in addressing the challenges posed by CSCs-rooted heterogeneity and drug resistance. [Display omitted] Notch pathway deactivation sensitizing cancer stem cells to photothermal therapy Newly designed near-infrared light-activatable prodrug A carrier-free self-assembled nanoparticle to co-deliver two therapeutic agents Dual-wavelength light to control separate drug functions Sequential light irradiation for maximized anti-tumor efficacy [ABSTRACT FROM AUTHOR]

While most Sonic Hedgehog-associated medulloblastomas (SHH-MBs) respond to therapeutic intervention, radiation therapy often causes deleterious long-term neurocognitive defects, especially in infants and young children. To limit neurological comorbidities, the development of a reduction-of-therapy treatment or de-escalation approach was investigated. Although retrospective analysis of MBs indicated low-dose therapy was potentially effective, clinical de-escalation trials showed poor outcomes in infant SHH-MBs and was prematurely terminated. Recent studies suggest the existence of cancer-stem-cell (CSC)-like cell populations that are more resistant to therapies and drive tumor recurrence. This review will discuss the mechanism of these CSC-like cells in SHH-MBs in resisting to p53-pathway activation, which may contribute to the disappointing outcomes of the recent de-escalation trials. [ABSTRACT FROM AUTHOR]

Background: Acquired therapeutic resistance and metastasis/recurrence remain significant challenge in advance renal cell carcinoma (RCC), thus the establishment of patient-derived cancer models may provide a clue to assess the problem. We recently characterized that neuritogenesis-related protein neuritin 1 (NRN1) functions as an oncogene in testicular germ cell tumor. This study aims to elucidate the role of NRN1 in RCC. Methods: NRN1 expression in clinical RCC specimens was analyzed based on immunohistochemistry. NRN1 -associated genes in RCC were screened by the RNA-sequencing dataset from The Cancer Genome Atlas (TCGA). RCC patient-derived cancer cell (RCC-PDC) spheroid cultures were established and their viabilities were evaluated under the condition of gene silencing/overexpression. The therapeutic effect of NRN1-specific siRNA was evaluated in RCC-PDC xenograft models. Results: NRN1 immunoreactivity was positively associated with shorter overall survival in RCC patients. In TCGA RCC RNA-sequencing dataset, C-X-C chemokine receptor type 4 (CXCR4), a prognostic and stemness-related factor in RCC, is a gene whose expression is substantially correlated with NRN1 expression. Gain- and loss-of-function studies in RCC-PDC spheroid cultures revealed that NRN1 significantly promotes cell viability along with the upregulation of CXCR4. The NRN1-specific siRNA injection significantly suppressed the proliferation of RCC-PDC-derived xenograft tumors, in which CXCR4 expression is significantly repressed. Conclusion: NRN1 can be a potential diagnostic and therapeutic target in RCC as analyzed by preclinical patient-derived cancer models and clinicopathological studies. [ABSTRACT FROM AUTHOR]

BackgroundAcquired therapeutic resistance and metastasis/recurrence remain significant challenge in advance renal cell carcinoma (RCC), thus the establishment of patient-derived cancer models may provide a clue to assess the problem. We recently characterized that neuritogenesis-related protein neuritin 1 (NRN1) functions as an oncogene in testicular germ cell tumor. This study aims to elucidate the role of NRN1 in RCC.MethodsNRN1 expression in clinical RCC specimens was analyzed based on immunohistochemistry. NRN1-associated genes in RCC were screened by the RNA-sequencing dataset from The Cancer Genome Atlas (TCGA). RCC patient-derived cancer cell (RCC-PDC) spheroid cultures were established and their viabilities were evaluated under the condition of gene silencing/overexpression. The therapeutic effect of NRN1-specific siRNA was evaluated in RCC-PDC xenograft models.ResultsNRN1 immunoreactivity was positively associated with shorter overall survival in RCC patients. In TCGA RCC RNA-sequencing dataset, C-X-C chemokine receptor type 4 (CXCR4), a prognostic and stemness-related factor in RCC, is a gene whose expression is substantially correlated with NRN1 expression. Gain- and loss-of-function studies in RCC-PDC spheroid cultures revealed that NRN1 significantly promotes cell viability along with the upregulation of CXCR4. The NRN1-specific siRNA injection significantly suppressed the proliferation of RCC-PDC-derived xenograft tumors, in which CXCR4 expression is significantly repressed.ConclusionNRN1 can be a potential diagnostic and therapeutic target in RCC as analyzed by preclinical patient-derived cancer models and clinicopathological studies.

HYD-PEP06, an endostatin-modified polypeptide, has been shown to produce effective anti-colorectal carcinoma effects through inhibiting epithelial–mesenchymal transition (EMT). However, whether HYD-PEP06 has similar suppressive effect on hepatocellular carcinoma (HCC) remained unknown. In this study, HYD-PEP06 inhibited metastasis and EMT but not proliferation in vitro. Cignal finder pathway reporter array and Western blot analysis revealed that HYD-PEP06 suppressed HCCLM3 cell metastasis and EMT by inhibiting the PI3K/AKT pathway. Moreover, HYD-PEP06 exerted anti-metastasis effects in HepG2 cancer stem-like cells (CSCs) via suppressing the WNT/ β -catenin signaling pathway. Finally, in HCCLM3 tumor-bearing BALB/c nu / nu nude mice, HYD-PEP06 substantially suppressed tumor growth, lung metastasis and HCC progress. Our results suggest that HYD-PEP06 inhibits the metastasis and EMT of HCC and CSCs as well, and thus has the potential as an agent for HCC treatment. HYD-PEP06 suppresses hepatocellular carcinoma (HCC) metastasis, epithelial–mesenchymal transition (EMT) and cancer stem cell (CSC)-like properties by inhibiting PI3K/AKT and WNT/ β -catenin signaling activation, which significantly inhibited progression of HCC. [Display omitted] [ABSTRACT FROM AUTHOR]

Increased oxidative phosphorylation (OXPHOS) and reactive oxygen species (ROS) levels are inherently linked. ROS are essential signaling molecules, with detrimental effects when produced in excess during chemotherapy, leading to cell death. Cancer stem-like cells (CSCs) are a subpopulation of tumor cells resistant to chemotherapy, highly invasive and metastagenic, driving malignant cancer behavior. In this study, we demonstrated that CSCs exhibit increased OXPHOS but paradoxically low ROS levels. Considering the detrimental effects of large amounts of ROS, CSCs have developed potential mechanisms for quenching excess ROS to maintain redox homeostasis. We aimed to investigate the distinct metabolic features and mechanisms of ROS regulation in gastric CSCs and explore potential therapeutic strategies targeting CSCs. Human gastric cancer cell lines, AGS and MKN1, were subjected to liquid chromatography/mass spectrometry-based metabolomic and microarray analyses. Mitochondrial properties such as mitochondrial mass, membrane potential, and ROS were assessed by flow cytometric analysis. CSCs with increased OXPHOS levels maintained low ROS levels by coupling FoxM1-dependent Prx3 expression and fatty acid oxidation-mediated NADPH regeneration. Thus, interventions targeting ROS homeostasis in CSCs may be a useful strategy for targeting this drug-resistant tumor cell subpopulation.

Glioblastoma (GBM) ranks among the most lethal cancers, with current therapies offering only palliation. Inter‐ and intrapatient heterogeneity is a hallmark of GBM, with epigenetically distinct cancer stem‐like cells (CSCs) at the apex. Targeting GSCs remains a challenging task because of their unique biology, resemblance to normal neural stem/progenitor cells, and resistance to standard cytotoxic therapy. Here, we find that the chromatin regulator, JmjC domain histone H3K36me2/me1 demethylase KDM2B, is highly expressed in glioblastoma surgical specimens compared to normal brain. Targeting KDM2B function genetically or pharmacologically impaired the survival of patient‐derived primary glioblastoma cells through the induction of DNA damage and apoptosis, sensitizing them to chemotherapy. KDM2B loss decreased the GSC pool, which was potentiated by coadministration of chemotherapy. Collectively, our results demonstrate KDM2B is crucial for glioblastoma maintenance, with inhibition causing loss of GSC survival, genomic stability, and chemoresistance.

Sunitinib (SUN) is a multi-targeted receptor tyrosine kinase inhibitor (TKI) that may lead to drug resistance and metastasis because of increased cancer stem-like cells (CSCs) due to the induction of hypoxia. Our group has proved that dopamine (DA) can specifically reduce CSC frequency and enhance the response of SUN in drug-resistant breast cancerand non-small cell lung cancer (NSCLC). In this study, DA and SUN combination therapy was investigated in the treatment of pancreatic cancer, a malignant tumor with high mortality rate and very limited therapies. The cytotoxicity assay, clone formation assay and wound healing assay in two pancreatic cancer cell line PANC-1 and SW1990 showed that DA could significantly increase the effect of SUN on cell survival, clone formation ability and migration ability. Besides, SW1990 cell-derived xenograft model and a pancreatic cancer patient-derived xenograft (PDX) model were constructed, further proving that DA could increase the in vivo anti-tumor efficacy of SUN, and could be reversed by SCH23390, a D1 dopamine receptor (D1DR) antagonist. Moreover, the CSC frequency of the combination groups was lower than the control groups or SUN monotherapy groups. In addition, the body weight, H&E staining and blood routine test results showed that the combination therapy was safe. In summary, DA and SUN combination therapy could be a promising strategy for the treatment of pancreatic cancer. [ABSTRACT FROM AUTHOR]

The prognosis of patients with high‐grade or advanced‐stage endometrial cancer remains poor. As cancer stem‐like cells (CSCs) are thought to be associated with endometrial cancers, it is essential to investigate the molecular mechanisms that regulate endometrial CSCs. Dual‐specificity phosphatase 6 (DUSP6) functions as a negative‐feedback regulator of MAPK–ERK1/2 signaling, but its role in endometrial cancer remains unknown. We investigated whether DUSP6 is involved in cancer cell stemness using endometrial cancer cell lines and specimens from endometrial cancer patients. DUSP6 induced the expression of CSC‐related genes including ALDH1, Nanog, SOX2 and Oct4A, increased the population of cells in the G0/G1 phase, and promoted sphere formation ability. DUSP6 knockdown resulted in reduced cell invasion and metastasis, whereas DUSP6 overexpression inhibited apoptosis under serum‐free conditions. Moreover, DUSP6 decreased phosphorylated ERK1/2 and increased phosphorylated Akt levels, which potentially induces CSC features. In patients with endometrial cancers, DUSP6 expression was determined using immunohistochemistry, and based on the results, the patients were dichotomized into high‐ and low‐DUSP6‐expression groups. Progression‐free survival and overall survival were significantly shorter in the high‐DUSP6‐expression group. These results suggest that DUSP6 has potential value as a biomarker of CSCs and as a target of therapies designed to eliminate CSCs in endometrial cancer. What's new? Although cancer stem‐like cells (CSCs) are involved in human endometrial cancers, the underlying molecular mechanisms and biomarkers for CSCs in endometrial cancers remain elusive. Here, the authors found that DUSP6 plays an important role in regulating endometrial CSC phenotypes by increasing self‐renewal ability and starvation resistance. DUSP6 expression was required for inducing invasion and metastasis and resulted in ERK1/2 dephosphorylation and Akt phosphorylation, which potentially contribute to the promotion of CSC phenotypes. As DUSP6 expression was also positively associated with worse progression‐free and overall survival, DUSP6 represents a potential biomarker for endometrial CSCs and a therapeutic target in endometrial cancers. [ABSTRACT FROM AUTHOR]

Low sensitivity of cancer stem cells toward regular cancer therapy strategies is an important issue in the field of cancer remedy. The concept of cancer stem cell elimination has been a topic of interest in the field of molecular medicine for a long time. At the current study, it was aimed to elevate the sensitivity of cancer stem-like cells toward radiotherapy by treating with Oct4–Sox2 complex decoy oligodeoxynucleotides (ODNs). After treating HT29 and HT29-ShE cells with Oct4–Sox2 complex decoy ODNs, and analyzing the cellular uptake and localization of decoys, treated cells and control groups were subjected to irradiation by fractionated 6MV X-ray with a final dose of 2 Gy. Thereafter, the influence of radiotherapy on ODNs treated groups and control group was investigated on cell viability, cell cycle, apoptosis, colonosphere formation and scratch assay. Cellular uptake and localization assays demonstrated that decoy ODNs can efficiently be transfected to the cells and reside in subcellular compartment, where they pose their action on gene regulation. Post radiotherapy analysis indicated statistical significance in decoy ODNs treated cells by means of lower cell viability, cell cycle arrest in G2/M phase, increased cellular apoptosis, and reduced cell motility. Also, formed colonospheres were smaller in size and fewer in numbers. Considering the role of Oct4, and Sox2 transcription factors in signaling pathways of preserving stemness and inducing reverse EMT, application of decoy strategy could increase the sensitivity of cancer cells toward irradiation, which has a potential to eliminate the cancerous cells from tumors and support cancer treatment. [ABSTRACT FROM AUTHOR]

The self-renewal and differentiation of cancer stem-like cells (CSCs) leads to cellular heterogeneity, causing one of the greatest challenges in cancer therapy. Growing evidence suggests that CSC-targeting therapy enhances the effect of concomitant antitumour therapy. To gain an in-depth understanding of this enhanced effect, the kinetic profile of estimated CSC frequency (the fraction of CSCs in tumour) was evaluated for in vivo characterization of cellular heterogeneity using sunitinib and dopamine as a paradigm combination therapy. Female MCF-7/Adr xenografted Balb/c nude mice were treated with sunitinib (p.o., 20 mg/kg) and dopamine (i.p., 50 mg/kg), alone or in combination. Estimated CSC frequency and tumour size were measured over time. Mechanistic PK/PD modelling was performed to quantitatively describe the relationship between drug concentration, estimated CSC frequency and tumour size. Sunitinib reduced tumour size by inducing apoptosis of differentiated tumour cells (DTCs) and enriched CSCs by stimulating its proliferation. Dopamine exhibited anti-CSC effects by suppressing the capacity of CSCs and inducing its differentiation. Simulation and animal studies indicated that concurrent administration was superior to sequential administration under current experimental conditions. Alongside tumour size, the current study provides mechanistic insights into the estimation of CSC frequency as an indicator for cellular heterogeneity. This forms the conceptual basis for in vivo characterization of other combination therapies in preclinical cancer studies. [ABSTRACT FROM AUTHOR]

Cancer stem cells are commonly tolerant toward chemotherapy and radiotherapy. Oct4 and Sox2 transcription factors are shown to be overexpressed in various cancers. At the current research, inhibition of Oct4 and Sox2 transcription factors was performed through application of decoy oligodeoxynucleotides (ODNs) strategy via repressing stemness properties in HT29-ShE cells encompassing enriched cancer stem-like cells. Designed Oct4–Sox2 complex decoy ODNs were transfected into HT29-ShE cells with Lipofectamine reagent. At the next step, ODNs efficiency transfection and subcellular localization were determined via flow cytometry and fluorescence microscopy, respectively. Further investigations such as cell proliferation and apoptosis analysis, colonosphere formation, invasion and migration, and real-time PCR assays were also carried out. Obtained results shed light on the fact that the designed complex decoys were effectively transfected into HT29-ShE cells, and they were found to be localized in subcellular compartments. Oct4–Sox2 decoy ODNs led to decreased cell viability, arresting the cell cycle in G0/G1 phases, increasing apoptosis, inhibition of migration/invasion and colonosphere formation ability of HT29-ShE cells in comparison with control and scramble groups. Furthermore, Oct4–Sox2 complex decoy could modulate the MET process via alteration of mRNA expression of downstream genes. It could be concluded that application of Oct4–Sox2 transcription factor decoy strategy in cells with stemness potential could lead to inhibiting the cell growth and triggering differentiation. Therefore, this technique could be applied along with usual remedies (chemotherapy and radiotherapy) as high potential method for treating cancer. [ABSTRACT FROM AUTHOR]

Background/Aims: Prior studies have shown that bufalin inhibits cellular proliferation and induces apoptosis in various human cancers. MicroRNA-203 (miR-203) has been shown to function as an important regulator of tumor progression at various stages. In this study, we investigated the effect of miR-203 expression and bufalin treatment on glioma cell proliferation and stem cell-like phenotypes. Methods: We used cell viability assay, colony formation assay, cell apoptosis assay and neurosphere formation assay to dectect the treatment effect of bufalin on U251 and U87 cells. Cells were transfected with the miR-203 mimic without bufalin treatment or cells were transfected with anti-miR-203 under bufalin treatment, the above expreiments were repeated. RT-PCR was employed to quantify miR-203 expression. Western blot was performed to detect the stem cell-like (CSC) markers, OCT4 and SOX2. Luciferase activity assay was used to determine whether the SPARC is the target of miR-203. Results: Bufalin treatment inhibited cell proliferation, colony formation, and CSC phenotypes and increased cell apoptosis and expression of miR-203. Furthermore, overexpression of miR-203 led to similar outcomes as bufalin treatment with respect to the cell viability, colony formation, cell apoptosis and the phenotypes of glioma cells. While anti-miR-203 attenuated the inhibitory effects of bufalin as promoting cell proliferation, colony formation and CSC phenotyes and inhibiting cell apoptosis. In addition, we identified SPARC as a novel target gene of miR-203. Conclusions: These findings suggest that miR-203 plays an important role in bufalin’s ability to inhibit the growth of glioma cells and the development of stem cell-like phenotypes.

Mitochondria are major organelles that play various roles in cells, and mitochondrial dysfunction is the main cause of numerous diseases. Mitochondrial dysfunction also occurs in many cancer cells, and these changes are known to affect malignancy. The mitochondria of normal embryonic stem cells (ESCs) exist in an undifferentiated state and do not function properly. We hypothesized that mitochondrial dysfunction in cancer cells caused by the depletion of mitochondrial DNA might be similar to the mitochondrial state of ESCs. We generated mitochondria dysfunctional (ρ0) cells from the Hep3B hepatocellular carcinoma cell line and tested whether these ρ0 cells show cancer stem-like properties, such as self-renewal, chemotherapy resistance, and angiogenesis. Compared with Hep3B cells, the characteristics of each cancer stem-like cell were increased in Hep3B/ρ0 cells. The Hep3B/ρ0 cells formed a continuous and large sphere from a single cell. Additionally, the Hep3B/ρ0 cells showed resistance to the anticancer drug doxorubicin because of the increased expression of ATP-binding cassette Subfamily B Member 1. The Hep3B/ρ0 conditioned medium induced more and thicker blood vessels and increased the mobility and invasiveness of the blood vessel cells. Therefore, our data suggest that mitochondrial dysfunction can transform cancer cells into cancer stem-like cells.

Although the detection of circulating tumor cells (CTCs) should be crucial for future personalized medicine, no efficient and flexible methods have been established. The current study established a polymeric custom-made chip for capturing CTCs with a high efficiency and flexibility. As an example of clinical application, the effects of self-expandable metallic stent (SEMS) placement on the release of cancer cells into the blood of patients with colorectal cancer and bowel obstruction were analyzed. This was assessed as the placement of SEMS may cause mechanical damage and physical force to malignant tissue, increasing the risk of cancer cell release into the bloodstream. The present study examined the number of CTCs using a custom-made chip, before, at 24 h after and at 4 days after SEMS placement in patients with colorectal cancer. The results revealed that, among the 13 patients examined, the number of CTCs was increased in three cases at 24 h after SEMS placement. However, this increase was temporary. The number of CTCs also decreased at 4 days after stent placement in most cases. The CTC chip of the current study detected the number of CD133-positive cancer stem-like cells, which did not change, even in the patient whose total number of CTCs temporarily increased. The results indicated that this custom-made microfluid system can efficiently and flexibly detect CTCs, demonstrating its potential for obtaining information during the management of patients with cancer. [ABSTRACT FROM AUTHOR]

Patients with osteosarcoma (OST) frequently relapse with drug resistant disease, consistent with the hypothesis that tumours contain a cancer stem-like cell (CSCs) population that survives chemotherapy to re-populate the tumour at local or metastatic sites. We describe a dual functional approach to isolate OST-CSCs and identify the ABC transporter proteins driving this population to reveal potential targets for the development of new treatments. OST-CSCs were isolated by selection in doxorubicin (OST-EC50 cells) and based on the ability to produce progeny from a single cell (HOS-EC50.SR cells). Pgp expression was increased in OST-EC50 cells, inducing resistance to doxorubicin, etoposide, vincristine and actinomycin D (p < 0.05). Increased expression of ABCG1 and Pgp protein in the HOS-EC50.SR cells induced resistance to etoposide and doxorubicin (p < 0.01), which was directly correlated with ABCG1 expression (r > 0.88, p < 0.001). Pgp expression is increased in both the HOS-EC50 cells where it mediates MDR and the HOS-EC50.SR populations, whereas ABCG1 was only upregulated in the self-renewing drug resistant HOS-EC50.SR cells. Targeting ABCG1 and Pgp may eradicate the drug resistant self-renewing OST-CSCs, leading to improved outcomes for patients with OST. [ABSTRACT FROM AUTHOR]

Chordoma is a rare, slow-growing tumor thought to arise from remnants of embryonic notochord associated with an aggressive outcome. Cancer stem-like cells (CSCs) are related to tumorigenesis, recurrence, and resistance in cancers. Therefore, chordoma CSCs are possible targets for chordoma treatment. In this study, dysregulated miRNAs were determined in chordoma CSCs and identified their role in chordoma. Dysregulated miRNAs were determined via miRNA microarray and validated through qPCR. miRNAs were transiently transfected to the chordoma cell lines and their roles in proliferation, apoptosis, migration and invasion capacities and stem-like properties were identified. Finally, a relationship between clinicopathological features and dysregulated miRNAs has been evaluated among 21 chordoma patients. CD133+CD15+ cells exhibited CSC phenotype with increased CSC- and Epithelial-Mesenchymal Transition (EMT)-related gene expression, invasion, migration, tumorosphere- and colony-forming abilities. In addition, WNT5A, TGF-α, BTG2 and MYCBP genes involved in CSC-related pathways, were targets of miR-140-3p, miR-148a-3p, miR-210-5p and miR-574-5p, respectively. Transfection of CSC-related miRNAs also increased migration and invasion along with stem cell phenotype. Finally, we determined that miR-140-3p and miR-148a-3p expressions correlated with Ki67 while miR-140-3p and TGF-α expressions were correlated with p53. Moreover, MYCBP expression was positively correlated with tumor volume, and metastasis was associated with the expression of miR-210-5p and TGF-α in our patient cohort. Through these findings, we conclude that chordoma CSCs have distinctive miRNA profile, which can regulate stem-like properties of chordoma CSCs. [ABSTRACT FROM AUTHOR]

Abstract Cancer stem-like cells (CSCs) treatment is a plausible strategy for enhanced cancer therapy. Here we report a glucose-installed sub-50-nm nanocarrier for the targeted delivery of small interfering RNA (siRNA) to CSCs through selective recognition of the glucose ligand to the glucose transporter 1 (GLUT1) overexpressed on the CSC surface. The siRNA nanocarrier was constructed via a two-step assembling process. First, a glucose-installed poly(ethylene glycol)- block -poly(l -lysine) modified with lipoic acid (LA) at the ω-end (Glu-PEG-PLL-LA) was associated with a single siRNA to form a unimer polyion complex (uPIC). Second, a 20 nm gold nanoparticle (AuNP) was decorated with ~65 uPICs through Au S bonding. The glucose-installed targeted nanoparticles (Glu-NPs) exhibited higher cellular uptake of siRNA payloads in a spheroid breast cancer (MBA-MB-231) cell culture compared with glucose-unconjugated control nanoparticles (MeO-NPs). Notably, the Glu-NPs became more efficiently internalized into the CSC fraction, which was defined by aldehyde dehydrogenase (ALDH) activity assay, than the other fractions, probably due to the higher GLUT1 expression level on the CSCs. The Glu-NPs elicited significantly enhanced gene silencing in a CSC-rich orthotopic MDA-MB-231 tumor tissue following systemic administration to tumor-bearing mice. Ultimately, the repeated administrations of polo-like kinase 1 (PLK1) siRNA-loaded Glu-NPs significantly suppressed the growth of orthotopic MDA-MB-231 tumors. These results demonstrate that Glu-NP is a promising nanocarrier design for CSC-targeted cancer treatment. Graphical abstract Unlabelled Image Highlights • Glucose-installed nanoparticle (Glu-NP) was made for cancer stem cell-targeted siRNA delivery. • Glu-NP was made by conjugating unimer polyion complexes on Au nanoparticle. • Enhanced cellular uptake of Glu-NP was observed in cancer stem cells in spheroid culture. • Glu-NP loaded with PLK1 siRNA suppressed growth of orthotopic breast tumor model. [ABSTRACT FROM AUTHOR]

Many patients diagnosed with acute myeloid leukemia (AML) relapse within two years of the initial remission. The biology of AML relapse is incompletely understood, although cancer stem-like (CSL) cells have been hypothesized to be important. To test this hypothesis, we employed SORE6, a reporter designed to detect the transcriptional activity of the embryonic stem cell proteins Oct4 and Sox2, to identify/purify CSL cells in two FLT3-mutated AML cell lines. Both cell lines contained ~10% of SORE6 + cells in the steady state. Compared to SORE6 - cells, SORE6 + cells exhibited more characteristics of CSL cells, with significantly higher chemoresistance and rates of spheroid formation. SORE6 + cells had substantially higher expression of Myc and FLT3 proteins, which are drivers of SORE6 activity. Using a mixture of SORE6 - /SORE6 + cells that were molecularly barcoded, we generated an in vitro study model for AML relapse. Specifically, after 'in vitro remission' induced by Ara-C, both cell lines regenerated after 13 ± 3 days. Barcode analysis revealed that most of the regenerated cells were derived from the original SORE6 + cells. Regenerated cells exhibited more CSL features than did the original SORE6 + cells, even though a proportion of them lost SORE6 activity. In bone marrow samples from a patient cohort, we found that relapsed blasts expressed significantly higher levels of Myc, a surrogate marker of SORE6 activity, compared to pre-treatment blasts. To conclude, using our in vitro model, we have provided evidence that CSL cells contribute to AML relapse.

Purpose: High-linear energy transfer (high LET) irradiation has significant cytotoxic effects on different cancerous stem-like cells (CSLCs) such as colorectal CSLCs. A review of the literature has indicated that the presence of gold nanoparticles (GNPs) enables low-LET irradiation to produce highly non-homogeneous dose distributions like high-LET irradiation. The purpose of this study was to evaluate the radioresponsiveness of HT29 colorectal CSLCs under low-LET irradiation (X-ray) and in the presence of GNPs.Methods: Radioresponsiveness was evaluated using the ϒ-H2AX foci formation assay, the clonogenic assay, the cell cycle progression assay and analyses of radiobiological parameters.Results: In the presence of GNPs, the survival fraction of HT29 CSLCs was significantly reduced and caused significant changes in the radiobiological parameters after irradiation. In addition, ϒ-H2AX assay showed that in the presence of GNPs, the persistent DNA double-strand breaks were significantly increased in irradiated HT29 CSLCs. The relative biological effectiveness value of GNPs with X-rays was about 1.6 for HT-29 CSLCs at the 10% of cell survival fraction (D10 level) when compared to X-rays alone.Conclusion: Therefore, the combination of GNPs with X-ray irradiation has the potential to kill HT29 CSLCs greater than the X-ray alone, and may be considered as an alternative for high-LET irradiation. [ABSTRACT FROM AUTHOR]

Background: Breast cancer is the leading cause of mortality from cancer in women worldwide, and cancer stem-like cell (CSC) is responsible for failure treatment of breast cancer. It plays an important role in resistant disease and metastasis. CD44/CD24 and ALDH are well-accepted protein markers of breast CSC, and it was reported that distinct subtypes of breast CSC were identified by the 2 markers. It is possible that there are various kinds of breast CSC which could be identified by different markers, and CSC markers utilized at present are not enough to fully understand breast CSC. Finding out more novel CSC markers is necessary. CXCR2 is involved in breast cancer metastasis, treatment resistance, and recurrence and has positive cross-talk with known breast CSC protein markers. It can be concluded that CXCR2 is related to breast CSC, and further study is in need.Results: In this study, we assessed expression of CXCR2 with immunohistochemistry in breast cancer tissues from 37 patients and discovered that level of CXCR2 was significantly lower in triple-negative breast cancer (TNBC) compared with non-TNBC. CXCR2 expression decreased in estrogen receptor-negative or HER2-negative breast cancer, but not progesterone receptor-negative counterparts. By immunofluorescence, we observed high coexpression rate of CXCR2 and CSC-related proteins, including NANOG and SOX2. To prove our speculation that CXCR2 was a novel CSC marker for TNBC, we used 4T1 cell, which is a TNBC cell line, to analyze CXCR2-positive subpopulations and observed that CXCR2-positive 4T1 cells showed characteristics of CSC, including resistance to cisplatinum, radiation, and hypoxia, low proportion (around 1%), much more tumor xenografts, tumor spherule formation, and higher levels of CSC-related mRNA compared with CXCR2-negative cells.Conclusion: CXCR2 is an acceptable and newly discovered CSC marker for only TNBC. [ABSTRACT FROM AUTHOR]

As a major common malignant tumor in women, the malignant behavior of breast cancer, which includes tumorigenesis and metastasis, is associated with estrogen, particularly 17β-estradiol (E2). With accumulating evidence demonstrating that cancer stem-like cells (CSCs) serve a function in the malignant behavior of breast cancer, including metastasis, recurrence and chemoresistance, the effects of E2 on the physiological processes of CSCs have been attracting more attention. In the present study, in order to investigate the effects of E2 on CSCs, CSCs from the MCF7 breast cancer cell line were isolated and treated with 1, 10 and 50 nM E2. Detection of cell proliferation following E2 treatment revealed that 10 nM E2 treatment inhibited cell proliferation, whereas 50 nM E2 treatment resulted in the induction of apoptosis on CSCs. In order to further investigate the effects of E2 treatment on migration, colony formation and the self-renewal capacity of CSCs in vitro, cells were treated with 1 and 10 nM E2. As expected, compared with mock group, the self-renewal capacity of the CSCs was slightly increased by 10 nM E2 treatment, while 1 nM exhibited no observable effect. E2 treatment demonstrated different effects on the proliferation, migration, colony formation and self-renewal capacity of CSCs in a dose-dependent manner. [ABSTRACT FROM AUTHOR]

Glioblastoma (GBM) ranks among the most lethal cancers, with current therapies offering only palliation. Inter‐ and intrapatient heterogeneity is a hallmark of GBM, with epigenetically distinct cancer stem‐like cells (CSCs) at the apex. Targeting GSCs remains a challenging task because of their unique biology, resemblance to normal neural stem/progenitor cells, and resistance to standard cytotoxic therapy. Here, we find that the chromatin regulator, JmjC domain histone H3K36me2/me1 demethylase KDM2B, is highly expressed in glioblastoma surgical specimens compared to normal brain. Targeting KDM2B function genetically or pharmacologically impaired the survival of patient‐derived primary glioblastoma cells through the induction of DNA damage and apoptosis, sensitizing them to chemotherapy. KDM2B loss decreased the GSC pool, which was potentiated by coadministration of chemotherapy. Collectively, our results demonstrate KDM2B is crucial for glioblastoma maintenance, with inhibition causing loss of GSC survival, genomic stability, and chemoresistance. [ABSTRACT FROM AUTHOR]

In a previous study, we found that DNAJB8, a heat shock protein (HSP) 40 family member is expressed in kidney cancer stem‐like cells (CSC)/cancer‐initiating cells (CIC) and that it has a role in the maintenance of kidney CSC/CIC. Heat shock factor (HSF) 1 is a key transcription factor for responses to stress including heat shock, and it induces HSP family expression through activation by phosphorylation. In the present study, we therefore examined whether heat shock (HS) induces CSC/CIC. We treated the human kidney cancer cell line ACHN with HS, and found that HS increased side population (SP) cells. Western blot analysis and qRT‐PCR showed that HS increased the expression of DNAJB8 and SOX2. Gene knockdown experiments using siRNAs showed that the increase in SOX2 expression and SP cell ratio depends on DNAJB8 and that the increase in DNAJB8 and SOX2 depend on HSF1. Furthermore, treatment with a mammalian target of rapamycin (mTOR) inhibitor, temsirolimus, decreased the expression of DNAJB8 and SOX2 and the ratio of SP cells. Taken together, the results indicate that heat shock induces DNAJB8 by activation of HSF1 and induces cancer stem‐like cells. [ABSTRACT FROM AUTHOR]

Background/Aims: Prior studies have shown that bufalin inhibits cellular proliferation and induces apoptosis in various human cancers. MicroRNA-203 (miR-203) has been shown to function as an important regulator of tumor progression at various stages. In this study, we investigated the effect of miR-203 expression and bufalin treatment on glioma cell proliferation and stem cell-like phenotypes. Methods: We used cell viability assay, colony formation assay, cell apoptosis assay and neurosphere formation assay to dectect the treatment effect of bufalin on U251 and U87 cells. Cells were transfected with the miR-203 mimic without bufalin treatment or cells were transfected with anti-miR-203 under bufalin treatment, the above expreiments were repeated. RT-PCR was employed to quantify miR-203 expression. Western blot was performed to detect the stem cell-like (CSC) markers, OCT4 and SOX2. Luciferase activity assay was used to determine whether the SPARC is the target of miR-203. Results: Bufalin treatment inhibited cell proliferation, colony formation, and CSC phenotypes and increased cell apoptosis and expression of miR-203. Furthermore, overexpression of miR- 203 led to similar outcomes as bufalin treatment with respect to the cell viability, colony formation, cell apoptosis and the phenotypes of glioma cells. While anti-miR-203 attenuated the inhibitory effects of bufalin as promoting cell proliferation, colony formation and CSC phenotyes and inhibiting cell apoptosis. In addition, we identified SPARC as a novel target gene of miR-203. Conclusions: These findings suggest that miR-203 plays an important role in bufalin's ability to inhibit the growth of glioma cells and the development of stem cell-like phenotypes. [ABSTRACT FROM AUTHOR]

Background High-grade serous ovarian cancer (HGSOC) causes 80% of all ovarian cancer (OC) deaths. In this setting, the role of cancer stem-like cells (CSCs) is still unclear. In particular, the evolution of CSC biomarkers from primary (pOC) to recurrent (rOC) HGSOCs is unknown. Aim of this study was to investigate changes in CD133 and aldehyde dehydrogenase-1 (ALDH1) CSC biomarker expression in pOC and rOC HGSOCs. Methods Two-hundred and twenty-four pOC and rOC intrapatient paired tissue samples derived from 112 HGSOC patients were evaluated for CD133 and ALDH1 expression using immunohistochemistry (IHC); pOCs and rOCs were compared for CD133 and/or ALDH1 levels. Expression profiles were also correlated with patients' clinicopathological and survival data. Results Some 49.1% of the patient population (55/112) and 37.5% (42/112) pOCs were CD133+ and ALDH1+ respectively. CD133+ and ALDH1+ samples were detected in 33.9% (38/112) and 36.6% (41/112) rOCs. CD133/ALDH1 coexpression was observed in 23.2% (26/112) and 15.2% (17/112) of pOCs and rOCs respectively. Pairwise analysis showed a significant shift of CD133 staining from higher (pOCs) to lower expression levels (rOCs) (p < 0.0001). Furthermore, all CD133 + pOC patients were International Federation of Gynaecology and Obstetrics (FIGO)-stage III/IV (p < 0.0001) and had significantly worse progression-free interval (PFI) (p = 0.04) and overall survival (OS) (p = 0.02). On multivariate analysis, CD133/ALDH1 coexpression in pOCs was identified as independent prognostic factor for PFI (HR: 1.64; 95% CI: 1.03–2.60; p = 0.036) and OS (HR: 1.71; 95% CI: 1.01–2.88; p = 0.045). Analysis on 52 pts patients with known somatic BRCA status revealed that BRCA mutations did not influence CSC biomarker expression. Conclusions The study showed that CD133/ALDH1 expression impacts HGSOC patients' survival and first suggests that CSCs might undergo phenotypic change during the disease course similarly to non stem-like cancer cells, providing also a first evidence that there is no correlation between CSCs and BRCA status. [ABSTRACT FROM AUTHOR]

Our previous studies have identified that CD166 works as a cancer stem-like cell (CSC) marker in epithelial cancers with a large repertoire of cellular functions. However, the post-translational regulatory mechanisms underlying CD166 turnover remain elusive. Several independent studies have reported that E3 ubiquitin ligase CHIP revealed significant biological effects through ubiquitin proteasome pathway on some kinds of malignant tumors. With analyzing the effects of CHIP expressions on stem-like cell populations, we found that CHIP represses CSC characteristics mainly targeting the CSC related protein CD166 in head and neck cancer (HNC). To investigate the role and relationship between CD166 and CHIP, HNC tissues and cell lines were used in this study. A significant negative correlation was observed between the expression levels of CHIP and CD166 in HNC patient samples. We also found that CHIP directly regulates the stability of CD166 protein through the ubiquitin proteasome system, which was also identified participating in the regulation of CSC behaviors in HNCs. Our findings demonstrate that CHIP-CD166-proteasome axis participates in regulating CSC properties in HNCs, suggesting that the regulation of CD166 by CHIP could provide new options for diagnosing and treating in the patients with HNCs. [ABSTRACT FROM AUTHOR]

The angiogenic factor, VEGFA, is a therapeutic target in ovarian cancer ( OVCA). VEGFA can also stimulate stem-like cells in certain cancers, but mechanisms thereof are poorly understood. Here, we show that VEGFA mediates stem cell actions in primary human OVCA culture and OVCA lines via VEGFR2-dependent Src activation to upregulate Bmi1, tumor spheres, and ALDH1 activity. The VEGFA-mediated increase in spheres was abrogated by Src inhibition or SRC knockdown. VEGFA stimulated sphere formation only in the ALDH1+ subpopulation and increased OVCA-initiating cells and tumor formation in vivo through Bmi1. In contrast to its action in hemopoietic malignancies, DNA methyl transferase 3A ( DNMT3A) appears to play a pro-oncogenic role in ovarian cancer. VEGFA-driven Src increased DNMT3A leading to miR-128-2 methylation and upregulation of Bmi1 to increase stem-like cells. SRC knockdown was rescued by antagomir to miR-128. DNMT3A knockdown prevented VEGFA-driven miR-128-2 loss, and the increase in Bmi1 and tumor spheres. Analysis of over 1,300 primary human OVCAs revealed an aggressive subset in which high VEGFA is associated with miR-128-2 loss. Thus, VEGFA stimulates OVCA stem-like cells through Src- DNMT3A-driven miR-128-2 methylation and Bmi1 upregulation. [ABSTRACT FROM AUTHOR]

Abstract Brain metastasis of breast cancer profoundly affects the cognitive and sensory functions as well as morbidity of patients, and the 1 year survival rate among these patients remains less than 20%. However, the pathological mechanism of brain metastasis is as yet poorly understood. In this report, we found that metastatic breast tumour cells in the brain highly expressed IL‐1β which then ‘activated’ surrounding astrocytes. This activation significantly augmented the expression of JAG1 in the astrocytes, and the direct interaction of the reactivated astrocytes and cancer stem‐like cells (CSCs) significantly stimulated Notch signalling in CSCs. We also found that the activated Notch signalling in CSCs up‐regulated HES5 followed by promoting self‐renewal of CSCs. Furthermore, we have shown that the blood‐brain barrier permeable Notch inhibitor, Compound E, can significantly suppress the brain metastasis in vivo. These results represent a novel paradigm for the understanding of how metastatic breast CSCs re‐establish their niche for their self‐renewal in a totally different microenvironment, which opens a new avenue to identify a novel and specific target for the brain metastatic disease.

Background Increasing evidence indicates that cancer stem cells (CSCs) and cancer stem-like cells form a special subpopulation of cells that are ubiquitous in tumors. These cells exhibit similar characteristics to those of normal stem cells in tissues; moreover, they are capable of self-renewal and differentiation, as well as high tumorigenicity and drug resistance. In prostate cancer (PCa), it is difficult to kill these cells using androgen signaling inhibitors and chemotherapy drugs. Consequently, the residual prostate cancer stem cells (PCSCs) mediate tumor recurrence and progression.Objective This review aims to provide a comprehensive and up-to-date overview of PCSCs, with a particular emphasis on potential therapeutic strategies targeting these cells.Methods After searching in PubMed and Embase databases using ‘prostate cancer’ and ‘cancer stem cells’ as keywords, studies related were compiled and examined.Results In this review, we detail the origin and characteristics of PCSCs, introduce the regulatory pathways closely related to CSC survival and stemness maintenance, and discuss the link between epithelial–mesenchymal transition, tumor microenvironment and tumor stemness. Furthermore, we introduce the currently available therapeutic strategies targeting CSCs, including signaling pathway inhibitors, anti-apoptotic protein inhibitors, microRNAs, nanomedicine, and immunotherapy. Lastly, we summarize the limitations of current CSC research and mention future research directions.Conclusion A deeper understanding of the regulatory network and molecular markers of PCSCs could facilitate the development of novel therapeutic strategies targeting these cells. Previous preclinical studies have demonstrated the potential of this treatment approach. In the future, this may offer alternative treatment options for PCa patients.

The theory of cancer stem-like cell (or cancer stem cell, CSC) has been established to explain how tumor heterogeneity arises and contributes to tumor progression in diverse cancer types. CSCs are believed to drive tumor growth and elicit resistance to conventional therapeutics. Therefore, CSCs are becoming novel target in both medical researches and clinical studies. Emerging evidences showed that nanoparticles effectively inhibit many types of CSCs by targeting various specific markers (aldehyde dehydrogenases, CD44, CD90, and CD133) and signaling pathways (Notch, Hedgehog, and TGF-β), which are critically involved in CSC function and maintenance. In this review, we briefly summarize the current status of CSC research and review a number of state-of-the-art nanomedicine approaches targeting CSC. In addition, we discuss emerging therapeutic strategies using epigenetic drugs to eliminate CSCs and inhibit cancer cell reprogramming.

Cancer stem-like cells (CSCs) exist in tumor tissues composed of heterogeneous cell population and are characterized by their self-renewal capacity and tumorigenicity. Many studies demonstrate that eradication of CSCs prevents development and recurrences of tumor; yet, molecules critical for the maintenance of CSCs have not been completely understood. We previously reported that Semaphorin3A (Sema3a) knockdown suppressed the tumorigenicity and proliferative capacity of Lewis lung carcinoma (LLC) cells. Therefore, we identified Sema3a as an essential factor for the establishment or maintenance of CSCs derived from LLC (LLC-stem cell). shRNA against Sema3a was introduced into LLC cells to establish a LLC-stem cell line and its effects on tumorigenesis, sphere formation, and mTORC1 activity were tested. Sema3a knockdown completely abolished tumorigenicity and the sphere-formation and self-renewal ability of LLC-stem cells. The Sema3a knockdown was also associated with decreased expression of mRNA for stem cell markers. The self-renewal ability abolished by Sema3a knockdown could not be recovered by exogenous addition of recombinant SEMA3A. In addition, the activity of mammalian target of rapamycin complex 1 (mTORC1) and the expression of its substrate p70S6K1 were also decreased. These results demonstrate that Sema3a is a potential therapeutic target in eradication of CSCs. [ABSTRACT FROM AUTHOR]

Cancer stem-like cells ( CSCs)/cancer-initiating cells ( CICs) are a small subpopulation of cancer cells that are responsible for the initiation, recurrence and metastasis of cancer. We previously demonstrated that, using the Hoechst 33342 dye-based side population technique, CSCs/ CICs in canine lung adenocarcinoma cell line exist. In this study, as CSCs/ CICs are known to form spheres in anchorage-independent environment in vitro, we evaluated the stemness of spheroid cells derived from canine lung adenocarcinoma and osteosarcoma cells by expression of stemness markers, and investigated radioresistance. Spheroid cells showed greater expression of stemness markers Oct-4 and CD133 gene than those of adherent-cultured cells. In nude mouse xenograft models, spheroid cells showed higher tumourigenic ability than adherent-cultured cells. In addition, spheroid cells showed significantly resistant against radioactivity as compared with adherent-cultured cells. These results suggest that spheroid cells could possess stemness and provide a CSCs/ CICs research tool to investigate CSCs/ CICs of canine tumour cells. [ABSTRACT FROM AUTHOR]