Cancer Stem Cells In Tumors Research Articles

Stem Cells, Cancer and the Theory of Cancer Stem Cells in Solid Tumours

Solid tumours are an immense cancer burden and a main therapeutic challenge. The theory of cancer stem cells provides an attractive cellular mechanism to account for the therapeutic resistance exhibited by many of these tumours. There is strong evidence that various solid tumours are hierarchically managed and sustained by notable subpopulations of cancer stem cells. Recent evidence of cancer stem cells emerged from a mouse model epithelial tumorigenesis, also some models of heterogeneity may apply. Haematopoietic stem cells (HSCs) have the capability to renew themselves and produce lineages of the blood; yet the signals that control HSc self-renewal remain indistinct. WnT signalling pathway has crucial role in the expression of activated p-catenin which expands the HSCs in a long-term cultures. In addition, Wnt signalling can interrupt the lymphocyte progenitor cells proliferation and affect the cells development. Other similar signalling pathways such as Notch and Hedgehog (Hh) are found in normal stem cells. Therapeutic targeting of cancer stem cells and tumour population could shed light on how to supress tumour growth. In this review, we suggest that by developing a new anti-cancer stem cell therapeutic agent that targets embryonic signalling pathways of cancer stem cells can improve the treatment of the disease

Abstract P1-03-06: GNBP2 suppresses tumor growth and cancer stem cell load of triple negative breast cancer by controlling STAT3 pathway

Abstract Background: Gametogenetin binding protein 2 (GGNBP2) is encoded in human chromosome 17q12-q23, a region known as a breast and ovarian cancer susceptibility locus. GGNBP2 has a single C2H2 zinc finger and a consensus LxxLL nuclear receptor (NR) binding motif. We have reported that GGNBP2 suppresses ERα-positive breast tumorigenesis by acting as a nuclear receptor co-repressor to restrain ERα activity. However, the detailed molecular mechanisms of GGNBP2 and its role in triple negative breast cancer (TNBC) remain largely unclear. Methods: A human breast cancer tissue array containing 138 human breast tumor tissues were utilized to examine GGNBP2 expression in breast cancer samples by IHC. To address the potential anti-breast tumor activity of GGNBP2 in vitro, we expressed exogenous GGNBP2 in TNBC cells, including MDA-MB-231 and Cal51 cell lines. Cell proliferation and cell cycle were assessed by cell growth curve/EdU assays and flow cytometry after propidium Iodide staining. Apoptosis was determined by flow cytometry after annexin V staining, by caspase 3/7 and caspase 9 activity assays. Cancer stem cell properties were determined by expression of CD44/CD24/ALDH1 markers. The levels of phosphorylated STAT3 and total STAT3 were determined by western blot. Quantitative PCR and Western blot were carried out to evaluate the effects of GGNBP2 overexpression on STAT3 target genes, CCND1, Mcl-1, survivin, bax and bim expression. Results: GGNBP2 expression is down-regulated in TNBC cells and patient tumors and it is associated with poor patient survival. Overexpression of GGNBP2 significanly induces cell cycle G0/G1 phase arrest and apoptosis in TNBC cell lines. Expression of cancer stem cell markers also decreased in GGNBP2-overexpressed TNBC cells. GGNBP2 reduces the expression levels of CCND1, Mcl-1 and survivin, promotes the expression levels of bax and bim proteins. Importantly, overexpression of GGNBP2 inhibits STAT3 phosphorylation and STAT3 downstream garget gene expression, including CCND1, Mcl-1 and survivin. Conclusion: GGNBP2 serves as a critical nuclear negative regulator of STAT3-mediated gene expression and tumorigenesis. Citation Format: Zhang J. GNBP2 suppresses tumor growth and cancer stem cell load of triple negative breast cancer by controlling STAT3 pathway [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-03-06.

Clinical significance of high expression of a specific solute carrier transporter in HCC.

303 Background: Hepatocellular carcinoma (HCC) is the third cause of cancer-related death. GNS561 (Genoscience Pharma, France) is a small molecule inducing apoptosis by lysosome inhibition and caspase activation. GNS561 has high hepatotropism and anti-tumorigenic capacity on tumor bulk and cancer stem cells. Its main target is a specific solute carrier transporter (SLCt). We describe here the clinical relevance of the overexpression of SLCt in HCC patients. Methods: The expression of SLCt was investigated by iQRT-PCR in surgically resected HCC tumors (T) and the matched non-tumor (NT) liver tissues (n=180) as well as healthy livers (HL) devoid of chronic or acute disease (n=10). Pearson's chi-squared test was employed for significant correlation tests while univariate and multivariate survival analysis were performed by Cox proportional hazard ratio (HR) method. Results: SLCt was overexpressed in 40.5% of T and 30.3% of NT as compared to HL. High SLCt in T was associated with microvascular emboli (p=0.034) and expression of the cancer stem cell markers Sox2 (p=0.025) and CD133 (p=0.034). High SLCt in NT correlated with cirrhosis (p=0.009) and presence of satellite nodules (p<0.001). Univariate analysis showed association between high SLCt in T and shortened overall survival (OS) (HR=1.08, p=0.020), lower progression-free survival (PFS) (HR=1.76, p=0.006) as well as early recurrence-free survival (ERFS) (within 2 years post-surgery) (HR=1.88, p=0.008). In multivariate analysis, high SLCt tended to be an independent factor for OS, and this was strongly significant for PFS and ERFS. High SLCt in NT, is quite a poor outcome factor on late recurrence-free survival (HR=2.33, p=0.056) together with cirrhosis in univariate analysis, but remained dependent of cirrhosis in multivariate analysis. Late recurrence is linked to the intrinsic tumorigenic status of the liver. Conclusions: Overexpression of the SLCt in HCC tumors is associated to stemness features and appears as a poor outcome factor impacting on early recurrence. Further, SLCt in NT is associated with development of de-novo HCC. Validation cohorts and prospective assessments are needed to define high SLCt as a potential biomarker of HCC stemness and patient outcome.

Stromal CD10 expression in breast cancer correlates with tumor invasion and cancer stem cell phenotype

BackgroundPrevious investigations have indicated that CD10 is associated with biological aggressivity in human cancers, but the use of this marker for diagnosis and prognosis is more complex. The aim of this study was to evaluate the expression of CD10 in breast cancer and its association with the clinicopathological features. In addition, we investigated whether a relationship exists between CD10 expression and cancer stem cells.MethodsCD10 expression was examined by the immunohistochemistry in a series of 133 invasive breast carcinoma cases. Results were correlated to several clinicopathological parameters. Cancer stem cell phenotype was assessed by the immunohistochemical analysis of CD44 and ALDH1.ResultsSignificant CD10 expression was found in the fusiform stromal cells in 19.5% of the cases and in the neoplastic cells in 7% of the cases. The stromal CD10 positivity was more frequently found in tumors with lymph node metastasis (p = 0.01) and a high histological grade (p = 0.01). However, CD10 expression by the neoplastic cells correlates with a high histological grade (p = 0.03) and the absence of estrogen (p = 0.002) as well as progesterone (p = 0.001) receptor expression.We also found that CD10 expression by the stromal cells, but not by the neoplastic cells, correlates significantly with the expression of cancer stem cell markers (CD44+/ALDH1+) (p = 0.002).ConclusionThese findings support the role of the stromal CD10 expression in breast cancer progression and dissemination, and suggest a relationship with cancer stem cells.

Ratiometric delivery of two therapeutic candidates with inherently dissimilar physicochemical property through pH-sensitive core–shell nanoparticles targeting the heterogeneous tumor cells of glioma

Currently, combination drug therapy is one of the most effective approaches to glioma treatment. However, due to the inherent dissimilar pharmacokinetics of individual drugs and blood brain barriers, it was difficult for the concomitant drugs to simultaneously be delivered to glioma in an optimal dose ratio manner. Herein, a cationic micellar core (Cur-M) was first prepared from d-α-tocopherol-grafted-ε-polylysine polymer to encapsulate the hydrophobic curcumin, followed by dopamine-modified-poly-γ-glutamic acid polymer further deposited on its surface as a anion shell through pH-sensitive linkage to encapsulate the hydrophilic doxorubicin (DOX) hydrochloride. By controlling the combinational Cur/DOX molar ratio at 3:1, a pH-sensitive core–shell nanoparticle (PDCP-NP) was constructed to simultaneously target the cancer stem cells (CSCs) and the differentiated tumor cells. PDCP-NP exhibited a dynamic diameter of 160.8 nm and a zeta-potential of –30.5 mV, while its core–shell structure was further confirmed by XPS and TEM. The ratiometric delivery capability of PDCP-NP was confirmed by in vitro and in vivo studies, in comparison with the cocktail Cur/DOX solution. Meanwhile, the percentage of CSCs in tumors was significantly decreased from 4.16% to 0.95% after treatment with PDCP-NP. Overall, PDCP-NP may be a promising carrier for the combination therapy with drug candidates having dissimilar physicochemical properties.

Stem Cells, Cancer and the Theory of Cancer Stem Cells in Solid Tumours

Stem Cells, Cancer and the Theory of Cancer Stem Cells in Solid Tumours

Challenging tumour immunological techniques that help to track cancer stem cells in malignant melanomas and other solid tumours.

Aim of the studyThe arsenal of questions and answers about the minor cancer initiating cancer stem cell (CSC) population put responsible for cancer invasiveness and metastases, has left with an unsolved puzzle. Specific aims of a complex project were partly focused on revealing new biomarkers of cancer. We designed and set up novel techniques to facilitate the detection of cancerous cells.Materials and methodsAs a novel approach, we investigated B cells infiltrating breast carcinomas and melanomas (TIL-B) in terms of their tumour antigen binding potential. By developing the TIL-B phage display technology we provide here a new technology for the specific detection of highly tumour-associated antigens. Single chain Fv (scFv) antibody fragment phage ELISA, immunofluorescence (IF) FACS analysis, chamber slide technique with IF confocal laser microscopy and immunohistochemistry (IHC) in paraffin-embedded tissue sections were set up and standardized.ResultsWe showed strong tumour-associated disialylated glycosphingolipid expression levels on various cancer cells using scFv antibody fragments, generated previously by uniquely invasive breast carcinoma TIL-B phage display library technology.ConclusionsWe report herein a novel strategy to obtain antibody fragments of human origin that recognise tumour-associated ganglioside antigens. Our investigations have the power to detect privileged molecules in cancer progression, invasiveness, and metastases. The technical achievements of this study are being harnessed for early diagnostics and effective cancer therapeutics.

CD44ICD promotes breast cancer stemness via PFKFB4-mediated glucose metabolism.

CD44 is a single-pass cell surface glycoprotein that is distinguished as the first molecule used to identify cancer stem cells in solid tumors based on its expression. In this regard, the CD44high cell population demonstrates not only the ability to regenerate a heterogeneous tumor, but also the ability to self-regenerate when transplanted into immune-deficient mice. However, the exact role of CD44 in cancer stem cells remains unclear in part because CD44 exists in various isoforms due to alternative splicing.Methods: Gain- and loss-of-function methods in different models were used to investigate the effects of CD44 on breast cancer stemness. Cancer stemness was analyzed by detecting SOX2, OCT4 and NANOG expression, ALDH activity, side population (SP) and sphere formation. Glucose consumption, lactate secretion and reactive oxygen species (ROS) levels were detected to assess glycolysis. Western blot, immunohistochemical staining, ELISA and TCGA dataset analysis were performed to determine the association of CD44ICD and PFKFB4 with clinical cases. A PFKFB4 inhibitor, 5MPN, was used in a xenograft model to inhibit breast cancer development.Results: In this report, we found that the shortest CD44 isoform (CD44s) inhibits breast cancer stemness, whereas the cleaved product of CD44 (CD44ICD) promotes breast cancer stemness. Furthermore, CD44ICD interacts with CREB and binds to the promoter region of PFKFB4, thereby regulating PFKFB4 transcription and expression. The resultant PFKFB4 expression facilitates the glycolysis pathway (vis-à-vis oxidative phosphorylation) and promotes stemness of breast cancer. In addition, we found that CD44ICD and PFKFB4 expressions are generally up-regulated in the tumor portion of breast cancer patient samples. Most importantly, we found that 5MPN (a selective inhibitor of PFKFB4) suppresses CD44ICD-induced tumor development.Conclusion: CD44ICD promotes breast cancer stemness via PFKFB4-mediated glycolysis, and therapies that target PFKFB4 (e.g., 5MPN therapy) may lead to improved outcomes for cancer patients.

Immune Cells in the Tumor Microenvironment and Cancer Stem Cells: Interplay for Tumor Progression

Immune Cells in the Tumor Microenvironment and Cancer Stem Cells: Interplay for Tumor Progression

Downregulation of Cancer Stemness by Novel Diterpenoid Ovatodiolide Inhibits Hepatic Cancer Stem Cell-Like Traits by Repressing Wnt/[Formula: see text]-Catenin Signaling.

The hierarchical tumor propagation or cancer stem cells (CSCs) model of carcinogenesis postulates that like physiologic adult stem cell (ASC), the CSCs positioned at the apex of any tumor population form the crux of tumor evolution with a constitutive regenerative capacity and differentiation potential. The propagation and recurrence of the characteristically heterogeneous and therapy-resistant hepatocellular carcinoma (HCC), adds to accumulating evidence to support this CSCs model. Based on the multi-etiologic basis of HCC formation which among others, focuses on the disruption of the canonical Wnt signaling pathway, this study evaluated the role of cembrane-type phytochemical, Ovatodiolide, in the modulation of the Wnt/[Formula: see text]-catenin pathway, and its subsequent effect on liver CSCs' activities. Our fluorescence-activated cell sorting (FACS) and quantitative RT-PCR analyses of side population (SP) indicated that CD133+ cells were [Formula: see text]-catenin-overexpressing, more aggressive, and resistant to the conventional anticancer agents, Cisplatin and Doxorubicin, when compared to [Formula: see text]-catenin-downregulated group. We demonstrated that marked upregulation of [Formula: see text]-catenin and its downstream targets effectively enhanced hepatosphere formation, with an associated induction of CD133, OCT4 and Sox2 expression and also caused an significant enhancement of HCC proliferation. However, treatment with Ovatodiolide induced downregulation of [Formula: see text]-catenin and its downstream effector genes, abolished hepatosphere formation and reversed the [Formula: see text]-catenin-associated enhancement of HCC growth. In summary, we demonstrated for the first time that Ovatodiolide suppressed the canonical Wnt signaling pathway, and inhibited the generation of liver CSCs; Thus, projecting Ovatodiolide as a putatively effective therapeutic agent for anti-HCC target therapy.

Intermittent calorie restriction enhances epithelial-mesenchymal transition through the alteration of energy metabolism in a mouse tumor model.

The effect of intermittent calorie restriction (ICR) on cancer is controversial. In this study, we examined the effects of ICR and food content in syngeneic BALB/c mice injected with CT26 mouse colon cancer cells. Mice were subjected to 24-h fasting once a week for 4 weeks, and then provided with a control, high-calorie, or trans fatty acid-rich diet. While ICR resulted in increases in tumor weights, metastasis and in the number of cancer stem cells (CSCs) in the tumors or blood of mice fed the control and high-fat diets, it had no effect on body weight after 4 weeks. In particular, we detected increases in the numbers of CSCs in the tumor or blood on the day after starvation, when food overconsumption was detected. Conversely, continuous calorie restriction had no effect on tumor weight, metastasis, or the number of CSCs in tumors or blood. In the post-starvation period, energy metabolism in the tumor was altered from oxidative phosphorylation to glycolysis/lactate fermentation, with the acquisition of the epithelial-mesenchymal transition (EMT) phenotype. Hyperglycemia at the post-starvation period induced the expression of insulin-like growth factor-1, hypoxia-induced factor-1α and Nanog, as well as the phosphorylation of Stat3. Taken together, these findings suggest that ICR induces an increase in the number of CSCs and enhances EMT by promoting the Warburg/Crabtree effect following post-fasting food overconsumption.

MiR-5100 increases the cisplatin resistance of the lung cancer stem cells by inhibiting the Rab6.

Cisplatin-based chemotherapy is the most commonly used treatment regimen for lung cancer. Cancer stem cells (CSCs) are postulated to be important promoters of drug resistance. We previously found that miR-5100 is overexpressed in lung cancer, but it is unknown whether and how miR-5100 regulates cisplatin resistance. Here, we demonstrated that miR-5100 was significantly up-regulated in CD44+ CD133+ lung cancer stem cells (LCSCs) compared with non-CSCs. Additionally, over-expression of miR-5100 increased CSC properties, cell growth, and tumor sphere formation in lung cancer cell line A549 or H1299, and that miR-5100 inhibitor significantly increased sensitivity of LCSCs to cisplatin in vitro. Surprisingly, the combination with miR-5100 inhibitor significantly decreased the IC50 of LCSCs to cisplatin. Furthermore, miR-5100 increased CSC properties and cisplatin resistance by inhibiting Rab6, a direct target gene of miR-5100. We demonstrated that miR-5100 overexpression increases the cisplatin resistance of the LCSCs through the mitochondrial apoptosis pathway. In conclusion, our results suggest that miR-5100 increases the cisplatin resistance of the LCSCs by inhibiting the Rab6. This study provides novel insight into the regulation of LCSCs by miRNA.

Linc-ROR promotes esophageal squamous cell carcinoma progression through the derepression of SOX9

BackgroundNovel therapies tailored to the molecular composition of esophageal squamous cell carcinoma (ESCC) are needed to improve patient survival. We investigated the regulatory network of long intergenic non-protein coding RNA, regulator of reprogramming (linc-ROR) and sex-determining region Y-box 9 (SOX9), and their therapeutic relevance in ESCC.MethodsLinc-ROR and SOX9 expression were examined in ESCC specimens, cell lines, and cultured tumorspheres. We investigated the effects of linc-ROR on SOX9 expression and malignant phenotypes by CCK8, colony formation, Transwell, and sphere-forming assay. The linc-ROR/SOX9 interaction mediated by multiple microRNAs (miRNAs) was confirmed by bioinformatic analysis, luciferase assay, and RNA-binding protein immunoprecipitation, transient overexpression or antagonizing endogenous candidate miRNAs. The effect of linc-ROR depletion on tumor growth was assessed by xenograft assay.ResultsA positive correlation between linc-ROR and SOX9 expression was found in clinical ESCC specimens (r = 0.562, P = 0.036), cell lines, and tumorspheres. Silencing of linc-ROR significantly inhibited cell proliferation, motility, chemoresistance, and self-renewal capacity. Mechanistically, linc-ROR modulating the derepression of SOX9 by directly sponging multiple miRNAs including miR-15b, miR-33a, miR-129, miR-145, and miR-206. Antagonizing these miRNAs counteracted with linc-ROR silencing, whereas the repression of SOX9 abrogated malignant phenotypes induced by the cocktail of miRNA inhibitors. Moreover, linc-ROR disruption was sufficient to attenuate tumor growth and cancer stem cell marker expression in vivo.ConclusionsOur results demonstrate that the linc-ROR–miRNA–SOX9 regulatory network may represent a novel therapeutic target for ESCC.

Semi-synthetic salinomycin analogs exert cytotoxic activity against human colorectal cancer stem cells

Salinomycin, a polyether antibiotic, is a well-known inhibitor of human cancer stem cells. Chemical modification of the allylic C20 hydroxyl of salinomycin has enabled access to synthetic analogs that display increased cytotoxic activity compared to the native structure. The aim of this study was to investigate the activity of a cohort of C20-O-acyl analogs of salinomycin on human colorectal cancer cell lines in vitro. Two human colorectal cancer cell lines (SW480 and SW620) were exposed to three C20-O-acylated analogs and salinomycin. The impact of salinomycin and its analogs on tumor cell number, migration, cell death, and cancer stem cell specifity was analyzed. Exposure of human colorectal cancer cells to the C20-O-acylated analogs of salinomycin resulted in reduced tumor cell number and impaired tumor cell migration at lower concentrations than salinomycin. When used at higher (micromolar) concentrations, these effects were accompanied by induction of apoptotic cell death. Salinomycin analogs further expose improved activity against cancer stem cells compared to salinomycin.

Amphiphilic Modulation of Glycosylated Antitumor Ether Lipids Results in a Potent Triamino Scaffold against Epithelial Cancer Cell Lines and BT474 Cancer Stem Cells.

The problems of resistance to apoptosis-inducing drugs, recurrence, and metastases that have bedeviled cancer treatment have been attributed to the presence of cancer stem cells (CSCs) in tumors, and there is currently no clinically indicated drug for their eradication. We previously reported that glycosylated antitumor ether lipids (GAELs) display potent activity against CSCs. Here, we show that by carefully modulating the amphiphilic nature of a monoamine-based GAEL, we can generate a potent triamino scaffold that is active against a panel of hard-to-kill epithelial cancer cell lines (including triple-negative breast) and BT474 CSCs. The most active compound of this set, which acts via a nonmembranolytic, nonapoptotic caspase-independent mechanism, is more effective than cisplatin and doxorubicin against these cell lines and more potent than salinomycin against BT474 CSCs. Understanding the combination of factors crucial for the enhanced cytotoxicity of GAELs opens new avenues to develop potent compounds against drug-resistant cancer cells and CSCs.

4PD - GGNBP2 suppresses tumor growth and cancer stem cell load of triple negative breast cancer by controlling STAT3 pathway

4PD - GGNBP2 suppresses tumor growth and cancer stem cell load of triple negative breast cancer by controlling STAT3 pathway

Les rebiopsies : pourquoi ? Comment ?

The wide number of oncogenic addictions becomes a therapeutic target in the management of non-small cell lung cancer (NSCLC). Their knowledge but also their modifications across time explain that new histological procedures are mandatory for clinicians. For EGFR mutations and ALK rearrangements, rebiopsy is needed for progressive disease to know the resistance type or histological transformation. For EFGR mutations, a new procedure is currently used: liquid biopsy.Several studies have assessed faisability and limitation of rebiopsy in NSCLC patients. Several technics could be used, EBUS, EBUS-TBNA, transthoracic biopsy, metastatic site biopsy. In case of contraindication, liquid biopsy allows to get DNA circulating tumor and blood cancer stem cells (CSC). These technics have a good specificity but the sensitivity is lower.To perform a rebiopsy at progression in some subtypes of non-small cell lung cancer is mandatory to improve the management of these patients.

Targeting the Wnt Pathway and Cancer Stem Cells with Anti-progastrin Humanized Antibodies as a Potential Treatment for K-RAS-Mutated Colorectal Cancer.

Purpose: Patients with metastatic colorectal cancer suffer from disease relapse mainly due to cancer stem cells (CSC). Interestingly, they have an increased level of blood progastrin, a tumor-promoting peptide essential for the self-renewal of colon CSCs, which is also a direct β-catenin/TCF4 target gene. In this study, we aimed to develop a novel targeted therapy to neutralize secreted progastrin to inhibit Wnt signaling, CSCs, and reduce relapses.Experimental Design: Antibodies (monoclonal and humanized) directed against progastrin were produced and selected for target specificity and affinity. After validation of their effectiveness on survival of colorectal cancer cell lines harboring B-RAF or K-RAS mutations, their efficacy was assessed in vitro and in vivo, alone or concomitantly with chemotherapy, on CSC self-renewal capacity, tumor recurrence, and Wnt signaling.Results: We show that anti-progastrin antibodies decrease self-renewal of CSCs both in vitro and in vivo, either alone or in combination with chemotherapy. Furthermore, migration and invasion of colorectal cancer cells are diminished; chemosensitivity is prolonged in SW620 and HT29 cells and posttreatment relapse is significantly delayed in T84 cells, xenografted nude mice. Finally, we show that the Wnt signaling activity in vitro is decreased, and, in transgenic mice developing Wnt-driven intestinal neoplasia, the tumor burden is alleviated, with an amplification of cell differentiation in the remaining tumors.Conclusions: Altogether, these data show that humanized anti-progastrin antibodies might represent a potential new treatment for K-RAS-mutated colorectal patients, for which there is a crucial unmet medical need. Clin Cancer Res; 23(17); 5267-80. ©2017 AACR.

Interest of integrins targeting in glioblastoma according to tumor heterogeneity and cancer stem cell paradigm: an update.

Glioblastomas are malignant brain tumors with dismal prognosis despite standard treatment with surgery and radio/chemotherapy. These tumors are defined by an important cellular heterogeneity and notably contain a particular subpopulation of Glioblastoma-initiating cells, which recapitulate the heterogeneity of the original Glioblastoma. In order to classify these heterogeneous tumors, genomic profiling has also been undertaken to classify these heterogeneous tumors into several subtypes. Current research focuses on developing therapies, which could take into account this cellular and genomic heterogeneity. Among these targets, integrins are the subject of numerous studies since these extracellular matrix transmembrane receptors notably controls tumor invasion and progression. Moreover, some of these integrins are considered as membrane markers for the Glioblastoma-initiating cells subpopulation. We reviewed here integrin expression according to glioblastoma molecular subtypes and cell heterogeneity. We discussed their roles in glioblastoma invasion, angiogenesis, therapeutic resistance, stemness and microenvironment modulations, and provide an overview of clinical trials investigating integrins in glioblastomas. This review highlights that specific integrins could be identified as selective glioblastoma cells markers and that their targeting represents new diagnostic and/or therapeutic strategies.

Abstract 2155: Small molecule NSC59984 suppresses cancer cell growth under hypoxia

Abstract Hypoxia is one of the main features of solid tumors, contributes to drug resistance and is associated with poor prognosis. We have reported that a small-molecule NSC59984 restores p53 signaling and degrades mutant p53 protein in cancer cells. We find that NSC59984-mediated p53 signaling restoration and mutant p53 degradation is significantly blocked by NAC, an inhibitor of reactive oxygen species (ROS), while, further enhanced by BSO, a chemical compound increasing ROS in cells. These results suggest that ROS is a factor required for the effect of NSC59984 on cancer cells. Cellular ROS is produced by hypoxia in solid tumors. We investigated the effect of NSC59984 on p53 pathway and cell death in p53 mutant colorectal cancer (CRC) cells cultured under hypoxia. NSC59984 increases p53 signaling in p53 mutant cancer cells under hypoxia, as it does under normoxia. The effect of NSC59984 under hypoxia is blocked by NAC. Moreover, NSC59984 decreases cancer cell viability in a dose-dependent manner under hypoxia similar to normoxia. Our results suggest that NSC59984 inhibits cancer cell growth under hypoxia. Hypoxia has been known to increase cancer stem cells in tumors, which is one of the reasons causing drug resistance. We then evaluate the effect of NSC59984 on the stem cell growth. NSC59984 significantly reduces colonosphere formation of SW480, DLD-1 and HT29 cells. CRC stem cell markers such as CD44 and ALDH are decreased in colonospheres upon NSC59984 treatment, suggesting that NSC59984 inhibits stem cell self-renewal or/and growth. Our results provide the rationale for administration of NSC59984 in solid tumors with or without hypoxia and in combination treatment with ROS activators. Citation Format: Shengliang Zhang, Lanlan Zhou, Wafik S. El-Deiry. Small molecule NSC59984 suppresses cancer cell growth under hypoxia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2155. doi:10.1158/1538-7445.AM2017-2155