CD133-positive Cancer Stem Cells Research Articles

Decorin suppresses stemness and migration potential of malignant peripheral nerve sheath tumor through inhibiting epidermal growth factor receptor signaling

Cancer stem cells (CSCs) play pivotal roles in the growth, invasion, metastasis, chemo-resistance in malignant peripheral nerve sheath tumor (MPNST). The current characterization of CSCs in MPNST is not complete. Decorin is a critical regulator of microenvironment, but its expression and function in CSCs of MPNST has not been studied. In the current study, Decorin levels and its relationship with lung and liver metastasis were determined in clinical specimens. Decorin expression in CD133-positive or CD44-positive CSCs was analyzed by RT-qPCR on cytospun MPNST cells after flow cytometry-based cell sorting. Decorin-positive cells were separated from Decorin-negative cells in transfected MPNST cell lines using a designed plasmid expressing red fluorescent protein (RFP) under a Decorin promoter. Tumor sphere formation, tumor growth, cell invasion, cell migration, and the resistance to chemotherapy-induced apoptosis were determined on Decorin-positive versus Decorin-negative MPNST cells. In vivo tumor growth was analyzed in mice receiving subcutaneous transplantation of Decorin-positive versus Decorin-negative MPNSTs. We found that Decorin levels were significantly downregulated in MPNST specimens, compared to non-tumorous adjacent tissue. Significantly lower Decorin levels were detected in MPNSTs with lung or liver metastasis compared to those without. Poorer patient survival was detected in Decorin-low MPNST, compared to Decorin-high subjects. More Decorin-negative cells were detected in CD133-positive MPNST cells than CD133-negative MPNST cells, and in CD44-positive MPNST cells than in CD44-negative MPNST cells. Compared to Decorin-positive MPNST cells, Decorin-negative MPNST cells generated significantly more tumor spheres in culture, were more invasive and migratory, and were more resistant to chemotherapy-induced apoptosis, likely due to the inhibition of epidermal growth factor receptor signaling by Decorin. Decorin-negative MPNST cells grew significantly larger tumor in vivo. Thus, depletion of Decorin may occur in CSCs in MPNSTs, serving possibly as a new therapeutic target.

CD44 positive cancer stem cells express invasion and metastasis markers: Analysis of three tongue squamous cell carcinoma cell lines

CD44 positive cancer stem cells express invasion and metastasis markers: Analysis of three tongue squamous cell carcinoma cell lines

Targeted delivery of a PD-1-blocking scFv by CD133-specific CAR-T cells using nonviral Sleeping Beauty transposition shows enhanced antitumour efficacy for advanced hepatocellular carcinoma

BackgroundCD133 is considered a marker for cancer stem cells (CSCs) in several types of tumours, including hepatocellular carcinoma (HCC). Chimeric antigen receptor-specific T (CAR-T) cells targeting CD133-positive CSCs have emerged as a tool for the clinical treatment of HCC, but immunogenicity, the high cost of clinical-grade recombinant viral vectors and potential insertional mutagenesis limit their clinical application.MethodsCD133-specific CAR-T cells secreting PD-1 blocking scFv (CD133 CAR-T and PD-1 s cells) were constructed using a sleeping beauty transposon system from minicircle technology, and the antitumour efficacy of CD133 CAR-T and PD-1 s cells was analysed in vitro and in vivo.ResultsA univariate analysis showed that CD133 expression in male patients at the late stage (II and III) was significantly associated with worse progression-free survival (PFS) (P = 0.0057) and overall survival (OS) (P = 0.015), and a multivariate analysis showed a trend toward worse OS (P = 0.041). Male patients with advanced HCC exhibited an approximately 20-fold higher PD-L1 combined positive score (CPS) compared with those with HCC at an early stage. We successfully generated CD133 CAR-T and PD-1 s cells that could secrete PD-1 blocking scFv based on a sleeping beauty system involving minicircle vectors. CD133 CAR-T and PD-1 s cells exhibited significant antitumour activity against HCC in vitro and in xenograft mouse models. Thus, CD133 CAR-T and PD-1 s cells may be a therapeutically tractable strategy for targeting CD133-positive CSCs in male patients with advanced HCC.ConclusionsOur study provides a nonviral strategy for constructing CAR-T cells that could also secrete checkpoint blockade inhibitors based on a Sleeping Beauty system from minicircle vectors and revealed a potential benefit of this strategy for male patients with advanced HCC and high CD133 expression (median immunohistochemistry score > 2.284).

Cancer stem cell isolation and characterization from lung cancer cells

Lung cancer is one of the most common cancers in the world and a leading cause of death. Cancer stem cells (CSCs) are the cells responsible for tumor initiation. CSCs features include self-renewal capacity, differentiation, high invasion-migration, and resistance to chemotherapy. CSCs are characterized by specific surface markers. CD133 is widely used as a marker of CSCs in many cancers, including lung cancer. CD133-positive cells are an important marker of lung cancer stem cells because they show characteristics of lung cancer CSCs. CSCs are less sensitive and/or resistant to conventional treatments, remaining viable and regenerating tumors after treatment. Treatments that can target CSCs will be able to destroy CSCs more effectively, leading to the disappearance of tumors. Currently, attempts are being made to develop therapeutics that can effectively target CSCs. These studies concern the isolation and characterization of CSCs. In this study, CD133-positive CSCs and CD133-negative cells were isolated from H460 cells, a large cell lung cancer model, by MACS method. CSCs properties were investigated by tumorSphere formation assay (2% agar plate), hanging drop assay and qPCR method. CD133 positivity of H460 cells was determined as 0.3%. It has been observed that CD133-positive cells show CSCs-specific self-renewal properties. It was determined that the CD133 gene expression difference between CD133-positive CSCs and CD133-negative cells was approximately 25-fold. It has been observed that CD133-positive CSCs express more pluripotency genes (such as OCT-4, SOX-2 and KLF-4) compared to CD133-negative cells.

Anatomical distribution of cancer stem cells between enhancing nodule and FLAIR hyperintensity in supratentorial glioblastoma: time to recalibrate the surgical target?

It is ge nerally accepted that glioblastoma (GBM) arise from cancer stem cells (CSC); however, there is little evidence on their anatomical distribution. We investigated the expression and distribution of SOX-2-positive and CD133-positive CSCs both in the enhancing nodule (EN) of GBM and in the FLAIR hyperintensity zones on a surgical, histopathological series of 33 GBMs. The inclusion criterion was the intraoperative sampling of different tumor regions individualized, thanks to neuronavigation and positivity to intraoperative fluorescence with the use of 5-aminolevulinic acid (5-ALA). Thirty-three patients (20 males and 13 females with a mean age at diagnosis of 56years) met the inclusion criterion. A total of 109 histological samples were evaluated, 52 for ENs and 57 for FLAIR hyperintensity zone. Considering the quantitative distribution of levels of intensity of staining (IS), ES (extent score), and immunoreactivity score (IRS), no difference was found between ENs and FLAIR regions for both the SOX-2 biomarker (respectively, IS p = 0.851, ES p = 0.561, IRS p = 1.000) and the CD133 biomarker (IS p = 0.653, ES p = 0.409, IRS p = 0.881). This evidence suggests to recalibrate the target of surgery for FLAIRECTOMY and 5-ALA could improve the possibility to achieve this goal.

Abstract 907: CD133 stimulates cell proliferationviaupregulation of amphiregulin in melanoma

Abstract Melanoma, a malignant transformation of melanocytes, accounts for 90% of skin cancer deaths due to its ability to efficiently metastasize to other organs. CD133, also known as Prominin1, is a pentaspan glycosylated transmembrane protein that is overexpressed in cancer stem cells from various tumors, including melanoma, and has been associated with tumor recurrence, chemoresistance, and metastasis. To characterize and target CD133-positive cancer stem cells, patient-derived melanoma cell lines BAKP and POT, harboring BRAFWT/NRASQ61K and BRAFWT/NRASQ61R driver mutations, respectively, were co-transduced with a Tet activator (rtTA3) and a Tet-on vector expressing CD133 (TRE3G-CD133) to produce stable doxycycline (Dox)-inducible cell lines. These cell lines were exposed to Dox (1µg/mL) to induce CD133 expression for 24 h; mRNA was extracted and subjected to RNA-seq analysis, followed by bioinformatic analyses, which revealed genes that are significantly up- or down-regulated by Dox-induced CD133 expression. Among the most significantly altered genes was amphiregulin (AREG), which increased 7-fold with Dox induction. These results were validated in both BAKP and POT cell lines by qPCR and immunoblot analysis. AREG binds EGFR and activates RAS/RAF/MEK/ERK and PI3K/AKT signaling pathways, leading to cell proliferation, survival, and migration. Consistently, cell cycle and cell growth analyses revealed that Dox-induced CD133 expression increases the percent of cells in S-phase of the cell cycle, leading to increased cell growth in BAKP cells. The role of CD133 in cell proliferation via AREG upregulation was further studied with immunofluorescent and flow cytometry analysis of proliferation markers PCNA, Ki67, as well as BrdU incorporation into newly synthesized DNA in Dox-induced BAKP cells, with or without siRNA knockdown of AREG. AREG may play an integral role in melanoma progression due to its vital function in cell proliferation, serving as an attractive target for novel therapeutics in melanoma and cancers exhibiting overexpression of both CD133 and AREG. Further studies using specific AREG inhibitors or RNAi knockdown in melanoma cell lines is currently ongoing, and can further elucidate molecular mechanisms highlighting the role(s) of CD133 and AREG in melanoma cancer stem cells. Citation Format: Cynthia M. Simbulan-Rosenthal, Nusrat Islam, Yoga Haribabu, Ryyan Alobaidi, Li-Wei Kuo, Azadeh Shalamzari, Adam Leibowitz, Joanna Moulton, Dean S. Rosenthal. CD133 stimulates cell proliferationviaupregulation of amphiregulin in melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 907.

Abstract 348: Efficacy of triple combination treatment with trametinib, mebendazole and CD133 RNA aptamer in recalcitrant NRAS-mutant melanoma cells

Abstract Malignant melanoma is the most aggressive form of skin cancer. Although kinase inhibitors have proven to be efficient with promising clinical results, the development of drug resistance is one of the major issues in targeted therapy. CD133, also known asProminin-1, is a membrane glycoprotein studied extensively as a cell surface marker for cancer stem cells. In our previous studies, mebendazole, a repurposed broad spectrum anti-helminthic agent, inhibited the growth of NRAS mutant melanoma cells in combination with trametinib, a MEK inhibitor. However, a CD133-positive cancer stem cell population remain resistant to this targeted therapy. Use of RNA aptamers in diagnostic as well as therapeutics has been studied recently in different types of cancer cells. Drug delivery of aCD133 aptamer coupled with doxorubicin has been found to inhibit the growth of liver cancer cells. In this study, we targeted the cancer stem cells expressing CD133 with RNA aptamers, in combination with trametinib and mebendazole to sensitize the cells to the combination treatment. Patient derived melanoma cell lines, BAKP and POT, harboring BRAFWT/NRASQ61K and BRAFWT/NRASQ61R driver mutations, were co-transduced with aTet-on vector expressing CD133 and a Tet activator. The doxycycline-induced and uninduced cells were subjected to single agent treatment with 100 nM trametinib, 100 nM mebendazole or 100 nM CD133 RNA aptamer, as well as dual and triple agent combinations for 24 or 48 hours. XTT cell viability and apoptotic assays such as AnnexinV-PI flow cytometry analysis revealed that the triple combination with trametinib, mebendazole and the CD133 aptamer was the most effective in inducing apoptotic cell death, even in the doxycycline-induced CD133-overexpressing melanoma cells. Further studies will use preclinical in vivo mouse xenograft models to investigate the effects on tumor growth of CD133 RNA aptamers in combination treatments, potentially making it available for clinical trials aiming to improve patient response to therapeutics against drug-resistant melanoma cells. Citation Format: Yoga Haribabu, Raymond Chien, Ryyan Alobaidi, Li-Wei Kuo, Nusrat Islam, Cynthia M. Simbulan-Rosenthal, Dean S. Rosenthal. Efficacy of triple combination treatment with trametinib, mebendazole and CD133 RNA aptamer in recalcitrant NRAS-mutant melanoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 348.

CD44-positive cancer stem cells from oral squamous cell carcinoma exhibit reduced proliferation and stemness gene expression upon adipogenic induction.

We proposed to assess adipogenic differentiation and its effect on the proliferation and stemness markers in CD44 + OSCC CSCs. D44 + CSCs were sorted by magnetic sorting from the single-cell suspension of the OSCC tumor. Adipogenic differentiation was induced by an adipogenic induction medium. Lipid droplet formation was confirmed by oil red O staining. The expression of the cell surface marker was analyzed by flow cytometry. Real-time qPCR was performed to examine the gene expression activity. CD44 + OSCC CSCs can differentiate into adipocytes and adipogenesis in these cells decrease their proliferation and stemness gene expression. Adipogenic induction can make the cancer stem cells from OSCC tumors lose their stemness potential. Oral cancer, especially OSCC, is a huge burden worldwide. Similar to other stem cells, cancer stem cells can differentiate into other lineage cells. Our study shows that the proliferation and stemness gene expression in the CSCs from OSCC tumors can be thwarted by inducing them to differentiate into adipocytes, which could be advantageous to find out new clinical approaches in the treatment of cancers, like OSCC.

A Study of CD44 Positive Cancer Cells in Epithelial Ovarian Cancer and their Correlation with P53 And Ki67.

Context Epithelial ovarian carcinomas are one of the most common lethal gynecological malignancies. There is no specific symptom or biomarker for detection of this malignancy in early stage. So, the advanced stage, nature of frequent recurrences, and resistance to chemotherapies make it very difficult to deliver proper treatment to patients. Efforts are on to identify the presence of cancer stem cell by using a specific biomarker in epithelial ovarian cancer in the early stage. Objectives This study aims to identify the CD44 positive cancer cells in epithelial ovarian carcinoma of different histopathological types. It also intends to correlate the expression of CD44 with the expression of p53 and Ki67. Materials and Methods Sections from diagnosed specimens of ovarian epithelial neoplasm had been fixed in 10% formalin and embedded in paraffin, and they were used for immunohistochemical (IHC) staining for CD44, p53, and Ki67, using a peroxidase kit with mouse monoclonal antibodies. Then, the slides were evaluated for both tumor cell percentage and intensity of immunoreactivity. Statistical Analysis Chi-square had been used to find the significance of study. Significance level was considered at p value < 0.05 Results In this study, 40 patients were included in a period of one and a half years. The present study suggested that the levels of CD44 expression were increased in epithelial ovarian cancer compared to borderline tumor. CD44 was positively correlated with the ki67 expression and tumor grade. High-grade serous, mucinous, and endometrioid tumors were associated with high CD44 expression. Positivity of CD44 was found significantly higher in case of positive status of p53 (z = 3.65; p < 0.0001). Conclusion We can correlate CD44 positive cancer stem cells with grade of ovarian carcinomas, but for prognostic significance and therapeutic applications, more corroborative and multicentric works in this field are needed. CD44 can be targeted for therapy in recurrent and resistant cases of ovarian cancer.

Phenotype-based single cell sequencing identifies diverse genetic subclones in CD133 positive cancer stem cells

Tumor heterogeneity is one of the ongoing huddles in the field of colon cancer therapy. It is evident that there are countless clones which exhibit different phenotypes and therefore, single cell analysis is inevitable. Cancer stem cells (CSCs) are rare cell population within tumor which is known to function in cancer metastasis and recurrence. Although there have been trials to prove intra-tumoral heterogeneity using single cell sequencing, that of CSCs has not been clearly elucidated. Here, we articulate the presence of heterogeneous subclones within CD133 positive cancer stem cells through single cell sequencing. As a proof of principle, we performed phenotype-based high-throughput laser isolation and single cell sequencing (PHLI-seq) of CD133 positive cells in a frozen tumor tissue obtained from a patient with colorectal cancer. The result proved that CD133 positive cells were shown to be heterogeneous both in copy number and mutational profiles. Single cancer stem cell specific mutations such as RNF144A, PAK2, PARP4, ADAM21, HYDIN, KRT38 and CELSR1 could be also detected in liver metastatic tumor of the same patient. Collectively, these data suggest that single cell analysis used to spot subclones with genetic variation within rare population, will lead to new strategies to tackle colon cancer metastasis.

Enhanced Expression of ABCB1 and Nrf2 in CD133-Positive Cancer Stem Cells Associates with Doxorubicin Resistance.

The precise mechanism about drug resistance of cancer stem cells (CSCs) has not yet been completely understood. Based on the expression of CD44 and CD133, two well-recognized cell surface markers for CSC identification, we tried to separate HCT8 colorectal cancer cells into different subpopulations and then investigated how the expression of CD44 and CD133 associated with doxorubicin (DXR) resistance. Interestingly, DXR resistance was observed in CD44+CD133+ (P < 0.01vs. all other subpopulations), but not in CD44+CD133− cells. CD44+CD133+ cells also showed an enhanced expression of ABCB1 and drug efflux ability (P < 0.001vs. all other subpopulations), but verapamil, an inhibitor of ABCB1, only partially mitigated the DXR resistance. Independent on the accumulation of DXR, lower level of reactive oxygen species and higher expression of Nrf2 were detected in CD44+CD133+ than CD44+CD133− cells (P < 0.05). Unexpectedly, silencing CD133 by siRNA only partially enhanced the cytotoxicity of DXR, but did not obviously change the expression of ABCB1 and the accumulation of DXR in CD44+CD133+ cells. Complex mechanisms, including drug excretion and redox regulation, are likely involved in the DXR resistance of CD133-positive cells, suggesting the difficulty of drug resistance problem in cancer chemotherapy.

Targeting the ABC transporter ABCB5 sensitizes glioblastoma to temozolomide-induced apoptosis through a cell-cycle checkpoint regulation mechanism

Glioblastoma multiforme (GBM) is a malignant brain tumor with a poor prognosis resulting from tumor resistance to anticancer therapy and a high recurrence rate. Compelling evidence suggests that this is driven by subpopulations of cancer stem cells (CSCs) with tumor-initiating potential. ABC subfamily B member 5 (ABCB5) has been identified as a molecular marker for distinct subsets of chemoresistant tumor-initiating cell populations in diverse human malignancies. In the current study, we examined the potential role of ABCB5 in growth and chemoresistance of GBM. We found that ABCB5 is expressed in primary GBM tumors, in which its expression was significantly correlated with the CSC marker protein CD133 and with overall poor survival. Moreover, ABCB5 was also expressed by CD133-positive CSCs in the established human U-87 MG, LN-18, and LN-229 GBM cell lines. Antibody- or shRNA-mediated functional ABCB5 blockade inhibited proliferation and survival of GBM cells and sensitized them to temozolomide (TMZ)-induced apoptosis in vitro Likewise, in in vivo human GBM xenograft experiments with immunodeficient mice, mAb treatment inhibited growth of mutant TP53, WT PTEN LN-229 tumors, and sensitized LN-229 tumors to TMZ therapy. Mechanistically, we demonstrate that ABCB5 blockade inhibits TMZ-induced G2/M arrest and augments TMZ-mediated cell death. Our results identify ABCB5 as a GBM chemoresistance marker and point to the potential utility of targeting ABCB5 to improve current GBM therapies.

Contribution of GPD2/mGPDH to an alternative respiratory chain of the mitochondrial energy metabolism and the stemness in CD133-positive HuH-7 cells.

HuH-7 cells, derived from human hepatocarcinoma, are known to contain the CD133-positive cancer stem cell populations. HuH-7 cells showed higher ATP synthesis activity through the respiratory chain compared to another human hepatocarcinoma cell line HepG2 and showed an especially higher glycerol-3-phosphate (G3P)-driven ATP synthesis (G3P-ATPase) activity. We found that the CD133-positive HuH-7 cells expressed high levels of GPD2 (glycerol-3-phosphate dehydrogenase or mGPDH) and showed high G3P-ATPase activity. Next, to elucidate the relationship between CD133 and GPD2, we inhibited downstream factors of CD133 and found that a p38 inhibitor decreased the expression of GPD2 and decreased the G3P-ATPase activity. Furthermore, GPD2-knockdown (GPD2-KD) cells exhibited strong reduction of the G3P-ATPase activity and reduction of lactic acid secretion. Finally, we validated the effect of GPD2-KD on tumorigenicity. GPD2-KD cells were found to show decreased anchorage-independent cell proliferation, suggesting the linkage of G3P-ATPase activity to the tumorigenicity of the CD133-positive HuH-7 cells. Inhibition of G3P-ATPase disrupts the homeostasis of energy metabolism and blocks cancer development and progression. Our results suggest inhibitors, targeting GPD2 may be potential new anticancer agents.

Nano Let‑7b sensitization of eliminating esophageal cancer stem‑like cells is dependent on blockade of Wnt activation of symmetric division.

The poor therapy response and poor prognosis of esophageal cancer has made it one of the most malignant carcinoma, and the complicated multidisciplinary treatment failed to achieve a long-term disease-free survival. To diagnose esophageal cancer at an earlier stage, and to improve the effect of anticancer therapy would improve the therapeutic efficacy. After retrospective analysis of the cancer samples of patients who received esophagectomy, we found the relevance between ratio of either ALDH1 or CD133-positive cancer stem cells and 2-year recurrence. Higher ratios of cancer stem cells indicated later clinical stages, and Wnt signaling activation was more frequent in later esophageal carcinoma. Further in bench studies, we explored the suppressive roles and the mechanisms involved in Let-7 on self-renewal in ECA-109 and ECA-9706 esophageal cancer stem cells. Isolated cancer stem cells naturally divide symmetrically and are therapy resistant. Therapy of fluorouracil and docetaxel both enriched the stem cells, proving the resistant characteristics of cancer stem cells. Wnt activation stimulated more symmetric division of stem cells, resulting in self-renewal promotion, which could be blocked by Let-7 overexpression. Furthermore, enforced Let-7 sensitized the stem cells to chemotherapies in a Wnt pathway inhibition-dependent manner, contributing to Let-7 sensitization of chemotherapeutic response. Wnt activation weakened the suppressive Let-7b through the sponge functions of CCAT-1, forming the negative feedback loop of Let-7b/Wnt/CCAT1. These results identified the crucial participation of stem cells in esophageal cancer occurrence and progression as the potent indicator, and also indicate the potential powerful agent of Let-7 nano-particles in treatment of cancer.

Notch Activation Modulates Bevacizumab Activity by CD44 Positive Cancer Stem Cells in Advanced Colon Cancer

Background: Notch pathway is involved in regulating colon cancer stem cells (CSCs), which play an important role in angiogenesis and resistance to conventional therapies. CD44 and CD133 are transmembrane glycoproteins reported as putative markers for isolating CSCs. High expression of Notch Intracellular Cleaved Domain (NICD) has been associated with resistance to anti-vascular endothelial growth factor therapy. Based on these reports, we evaluated NICD, CD44 and CD133 expression in a series of consecutive metastatic colon cancer patients treated with bevacizumab-based chemotherapy within first-line clinical trials. Methods: Histological samples obtained from 45 primary adenocarcinomas were tested by immunohistochemistry for NICD, CD44 and CD133. A scoring system based on staining intensity and percentage of stained cells was used. Vessels density was measured in hot-spot areas by CD31 antibody. Results: CD44 levels were higher in high NICD cases than in low NICD cases (63% vs. 16%, respectively, p=0.014). High NICD and CD44 levels predicted shorter progression-free (p<0.001) and overall survival (p=0.012). No significant association was found between CD133 or CD31 and NICD or CD44 expression. Conclusion: Our data suggest that colon cancer patient with high NICD and CD44 levels have a reduced likelihood of response to bevacizumab-based therapy.

Abstract B29: The elucidation for functional roles of Metadherin in metastatic cascade of pancreatic cancer

Abstract Introduction: Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers. At present, surgical resection is the only curative treatment for PDAC, but the majority of PDAC patients show early recurrence even after curative resection. There is a possibility of having been distant micrometastasis at early stage of carcinogenesis in PDAC. The control of PDAC metastatic progression leads to improve the prognosis of PDAC patients. Recently, it is reported that a verified mediator of distant metastasis, Metadherin (MTDH), promotes metastasis in experimental models of breast cancer, and its high expression is associated with poor prognosis in a large spectrum of cancer types. Recent evidences imply that the epithelial-mesenchymal transition (EMT) and putative cancer stem cell (CSC) functions orchestrates to play crucial roles in cancer progression. In this study, we aim to investigate the function of MTDH in PDAC progression concomitant with undergoing EMT/MET plasticity or involving putative CSC functions. Experimental methods: We investigated MTDH expression in 7 human and 6 mouse PDAC cell lines and elucidated the roles of MTDH in PDAC progression by in vitro experiments for the loss of function using siMTDH and shMTDH. In immunohistochemical (IHC) staining of MTDH in resected PDAC tissues, we analyzed the correlation between MTDH expression and the clinico-pathological parameters as well as clinical outcome of the 82 PDAC patients. Results: Western blot analyses showed higher MTDH protein expression in metastatic PDAC compared to primary PDAC cell lines. In metastatic cell lines, MTDH expression has a positive correlation with E-cadherin expression. These data suggest that MTDH might be related to mesenchymal-epithelial transition (MET) and play a crucial role in metastatic cascade of PDAC. Conversely, MTDH has a negative correlation with E-cadherin in primary PDAC cell lines. It is implicated that MTDH might play inverse functions in primary site and metastatic site. Next, to examine what is the role of MTDH in the EMT/MET process, we evaluated the expression pattern of EMT markers and MTDH in response to transient TGF-β1 treatment. We found that E-cadherin expression decreases at 8 to 24 hours after treatment (EMT initiation), and then comes back to increase of the expression at 4 days after treatment (MET induction). While MTDH and E-cadherin expression shows an inverse relation during EMT initiation, these two expressions have a positive correlation during MET period (from 7 days after treatment). Additionally, we found EMT induction by TGF-β1 is attenuated by knockdown of MTDH, These results suggest MTDH might contribute to the phenotypic switch of PDAC cells via the EMT/MET process. MTDH knockdown significantly impaired the ability of pancreatosphere formation in PDAC cells and sensitized PDAC cells to gemcitabine. In FACS analyses, we also found that the percentage of CD133-positive cancer stem cell subpopulation was significantly reduced in MTDH knockdown metastatic PDAC cells. In anoikis assay, (this assay evaluate the resistance for apoptosis after losing contact from extracelluar matrix), MTDH knockdown reduced anoikis resistance in PDAC cells. These data indicate that MTDH might foster putative CSC functions in PDAC cells. In IHC staining, high MTDH expression indicated significantly higher incidence of hematogenous metastasis (p=0.02). Furthermore, High expression group showed poorer prognosis of PDAC patients compared to Low expression group in Kaplan Meier analysis (p=0.029). Conclusions: MTDH might promote PDAC metastasis to undergo EMT in primary PDAC and MET in metastatic PDAC along with.putative CSC functions. The regulation of MTDH might develop the new strategy for PDAC treatment, and lead to improve the outcome of patients. Citation Format: Kensuke Suzuki, Shigetsugu Takano, Hideyuki Yoshitomi, Shingo Kagawa, Hiroaki Shimizu, Masayuki Otsuka, Katunori Furukawa, Tukasa Takayashiki, Satoshi Kuboki, Daisuke Suzuki, Nozomu Sakai, Hiroyuki Nojima, Masaru Miyazaki.{Authors}. The elucidation for functional roles of Metadherin in metastatic cascade of pancreatic cancer. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr B29.

ABCG2 is required for self-renewal and chemoresistance of CD133-positive human colorectal cancer cells.

There is increasing evidence supporting the cancer stem cell (CSC) hypothesis, which suggests thata population of tumor cells with stem cell characteristics is responsible for tumor growth, resistance, and recurrence as well as drug resistance. In colorectal cancer, the CD133 antigen definesdistinct cell subpopulations that are rich in tumor-initiating cells; however, the drug resistance properties of these CD133-positive cells have not been well defined. The breast cancer resistance protein (BCRP)/ATP-binding cassette subfamily G member 2 (ABCG2) ispresent on the plasma membrane of many types of human cancer cells and contributes to multidrug resistance during chemotherapy. Theresults of the present study showed that ABCG2 is expressed in CD133-positive CSCs from human colorectal tumors. Furthermore, the downregulation of ABCG2 expression inhibited the self-renewal capacity of these cells, and significantly enhanced the efficacy of chemotherapy-induced apoptosis in LS174T colon adenocarcinoma cells and CD133-positive colorectal carcinoma cells. Together, these data show that ABCG2 expression correlates with the presence of CD133-positive cancer cells, and thus is a possible therapeutic target for colorectal cancer.

Abstract 3347: Establishment of four novel HPV-16 positive cell lines of invasive cervical carcinoma of Indian origin and characterization of CD133 positive cancer stem cells

Abstract Background and Aim: Cancer of the cervix is the 2nd most common cancer in Indian women. Cell lines are essential in vitro models in cancer research. Till date, available cell lines in cervical cancer were highly passaged, developed from Caucasian, Black or Asian origin; hence, establishment of a low-passage cervical cancer derived cell line was the first aim of this study. Cancer stem cells (CSCs) are proposed to be responsible for metastasis and therapy resistance. Previously, we reported CD133 to be a putative marker for CSC, and they were further characterized. Materials and Methods: 25 women were recruited after informed consent and approval from the Institute Ethics committee. A small portion of the biopsy was collected in DMEM/F12 media and subjected to primary culture. Successful propagation was possible in 4 cases. Their morphology, epithelial nature and HPV status were evaluated. Variable Number Tandem Repeat (VNTR) assay, cell cycle and kinetic studies were performed. Tissue expression of CD133 and CD49f stem cell markers was evaluated by direct immunofluorescence on frozen tumor samples. Adherent cells were sorted into CD133+ vs CD133- tumor bulk from all 4 cell lines by FACS. These two populations were evaluated for differences in tumorosphere formation, chemosensitivity to cisplatinum, expression of stemness (SOX2, OCT4, NANOG) and EMT (SNAIL, SLUG, TWIST, VIMENTIN and E-CADHERIN) markers at the transcript level. Observations: Four cell lines designated RSBS-9, RSBS-14, RSBS-23 derived from non-keratinizing squamous cell carcinoma and RSBS-43 derived from adenocarcinoma cervix were established and passaged up to 50 times. The epithelial nature of cell lines was confirmed by cytokeratin and epithelial membrane antigen positivity. VNTR assay confirmed derivation of cell lines from respective parental tissue sample. All 4 cell lines were HPV-16positive. The cell doubling time was approximately 48 hours. Immunofluorescence on tissue samples revealed diffuse positivity for CD49f indicating that it may not represent a CSC marker as previously reported whereas CD133 staining showed scattered positive cells. No particular location of CD133+ CSC was observed. Comparison of CD133+ with CD133- bulk population cells revealed increased tumorosphere formation; however, no significant difference in the chemosensitivity to cisplatinum was seen. Real time quantitation of transcripts of stemness and EMT markers revealed CD133+ cells showing upregulation of EMT markers VIMENTIN, SNAIL, SLUG in the RSBS-23 cell line and of VIMENTIN and TWIST in RSBS-9 cell line whereas there was no significant difference in the RSBS-14 and RSBS-43 cell lines for any of the markers studied. Conclusion: Low passage cell lines are useful model systems for understanding the biology of cervical cancer. CD133+ Cancer Stem cells exhibit some EMT markers in 2 of the 4 cell lines established. Citation Format: Shifa Javed, Bal Krishan Sharma, Sanjeev Kumar Sharma, Swati Sood, Rashmi Bagga, Shalmoli Bhattacharyya, Radhika Srinivasan. Establishment of four novel HPV-16 positive cell lines of invasive cervical carcinoma of Indian origin and characterization of CD133 positive cancer stem cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3347.

Abstract A65: Nodal contributes to cisplatin resistance in ovarian cancer cells.

Abstract The capacity of ovarian tumors to grow and propagate is dependent on a small subset of tumor cells, termed cancer stem-like cells, which contribute to drug resistance, and metastasis. Nodal, an embryonic morphogen has been found to sustain stem cell pluripotency and cellular plasticity, but in cancer cells its expression promotes cancer stem cell renewal, tumor growth, invasion, angiogenesis and metastasis. The role of Nodal in the development of recurrent chemoresistant ovarian cancer (OC) has not been previously investigated. The aim of this study was to investigate whether Nodal can modulate resistance of OC cell line A2780s to cisplatin. Methods. Human OC cell line A2780s was cultured in DMEM/F12 medium supplemented with 10% FBS and treated with cisplatin. Cytotoxity of cisplatin was determined by MTT assay (Roche) and clonogenic assay. Nodal expression after cisplatin treatment was determined by digital PCR and immunofluorescence staining. To increase Nodal signaling, we used a Nodal expression vector (versus an empty pcDNA3.3 vector; pcDNATM3.3-TOPO cloning kit; Invitrogen). We also employed recombinant human Nodal (rhNodal; R&amp;D). Transfection was performed with Lipofectamine (Invitrogen) as per manufacture instructions. Cell cycle analysis after cisplatin treatment and expression of cancer stem cell marker CD133 were determined using flow cytometry analysis (FACS). In vitro sphere limiting diluting assay was applied to measure ovarian cancer stem cell (OCSC) self-renewal. Results. The expression of Nodal increased significantly in A2780s cells after 24h cisplatin treatment (20,000 copies/1ug RNA versus 800 copies/1ug RNA in untreated cells) and retained for 96h after cisplatin withdrawal (120,000 copies/1ug RNA). Overexpression of Nodal rendered A2780s cells more resistant to cisplatin (IC50 2.9ug/ml) compared to control cells (IC50 1.3ug/ml). Treatment of A2780s cells with rhNodal (100ng for 24h) during cisplatin treatment increased the ability of ovarian cancer cells to form spheres. FACS analysis revealed that cisplatin along with rhNodal treatment increased the population of CD133 positive cancer stem cells in A2780s cell line (5.85% versus 0,65% in untreated cells and 1.75% after cisplatin treatment alone). Treatment of A2780s cells with rhNodal prevented cell arrest in S phase after cisplatin treatment (19.4% of cells in S phase after rhNodal+cisplatin versus 63.6% - after cisplatin alone). Conclusison. Our findings demonstrate that Nodal may contribute to cisplatin resistance in OC cells and tumor initiation capacity after drug therapy, and may hold promise as a therapeutic target to prevent chemoresistant recurrence. Citation Format: Olena Bilyk, Lynne-Marie Postovit. Nodal contributes to cisplatin resistance in ovarian cancer cells. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr A65.

Prognostic role of the cancer stem cell marker CD44 in ovarian cancer: a meta-analysis.

This meta-analysis study aimed to investigate the correlation between CD44-positive cancer stem cells (CSCs) and clinicopathological features and its effect on the survival of ovarian cancer patients. A comprehensive literature search in the electronic databases, including PubMed, EMBASE, and Wanfang (up to December 1, 2015), was conducted. Publications assessing the clinical or prognostic significance of CD44 expression in ovarian cancer were identified and reviewed until December 1, 2015. A meta-analysis was then performed to examine the association between CD44 expression and clinical outcomes of ovarian cancer. A total of 8 publications comprising 957 cases satisfied the criteria and were included for this meta-analysis. Our results show that CD44 expression was not significantly associated with the tumor grade (OR = 2.31, 95%CI = 0.61-8.73, P = 0.22), age of the patients (OR = 0.89, 95%CI = 0.32- 2.53, P = 0.83), residual tumor size (OR = 1.01, 95%CI = 0.30-3.40, P = 0.99), or response to chemotherapy (OR = 3.49, 95%CI = 0.51-23.65, P = 0.20). However, our meta-analyses of the data from the identified studies demonstrate that CD44 expression was significantly correlated with tumor lymphatic metastasis (OR = 2.66, 95%CI = 1.36-5.22, P = 0.004), tumor TNM stage (OR = 2.34, 95%CI = 1.76-3.12, P < 0.00001), and decreased overall survival for ovarian cancer patients (RR = 1.47, 95%CI = 1.23- 1.74, P < 0.0001). In conclusion, our findings show that CD44-positive ovarian cancer patients exhibit worse prognosis, which was associated with common clinicopathological features and poor prognostic factors.