• Asian Pacific Journal of Cancer Prevention
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• v.16 no.12
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• pp.4849-4852
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• 2015

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been investigated as an effective agent to treat various cancers. Cancer stem cells are resistant to TRAIL treatment, but the mechanism of TRAIL resistance remains unknown. In this study, brain cancer stem cells were isolated by CD133 magnetic sorting, and the number of CD133 positive cells detected by flow cytometry. The self-renewing capacity of brain cancer stem cells was examined by a neurosphere formation assay, and the percentage of cell death after TRAIL treatment was examined by an MTS assay. Expression of DR5, FADD, caspase 8 and BCL2 proteins was detected by western blot. The amount of CD133 positive cells was enriched to 71% after CD133 magnetic sorting. Brain cancer stem cell neurosphere formation was significantly increased after TRAIL treatment. TRAIL treatment also reduced the amount of viable cells and this decrease was inhibited by a caspase 8 inhibitor or by the pan-caspase inhibitor z-VAD (P<0.05). Brain cancer stem cells expressed lower levels caspase 8 protein and higher levels of BCL2 protein when compared with CD133 negative cells (P<0.05). Our data suggest that TRAIL resistance is related to overexpression of BCL2 and low expression of caspase 8 which limit activation of caspase 8 in brain cancer stem cells.

• Molecules and Cells
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• v.40 no.5
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• pp.322-330
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• 2017

This study investigated the role of cancer/testis antigen DDX53 in regulating cancer stem cell-like properties. DDX53 shows co-expression with CD133, a marker for cancer stem cells. DDX53 directly regulates the SOX-2 expression in anti-cancer drug-resistant $Malme3M^R$ cells. DDX53 and miR-200b were found to be involved in the regulation of tumor spheroid forming potential of Malme3M and $Malme3M^R$ cells. Furthermore, the self-renewal activity and the tumorigenic potential of $Malme3M^R$-CD133 (+) cells were also regulated by DDX53. A miR-200b inhibitor induced the direct regulation of SOX-2 by DDX53 We therefore, conclude that DDX53 may serve as an immunotherapeutic target for regulating cancer stem-like properties of melanomas.

• Reproductive and Developmental Biology
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• v.32 no.2
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• pp.105-110
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• 2008

The endogenous retrovirus-like elements (HERVs) found on several human chromosomes are somehow involved in gene regulation, especially during the transcription level. HERV-H, located on chromosome Xp22, may regulate gastrin-releasing peptide receptor (GRPR) in connection with diverse diseases. By suppression subtractive hybridization screen on SV40-immortalized lung fibroblast (WI-38 VA-13), we discovered that expression of HERV-HX2, a clustered HERV-H sequence on chromosome X, was upregulated in immortalized lung cells, compared to that of normal cells. Expression of HERV-HX2 was then analyzed in various cell lines, including normal somatic cells, cancer cells, SV40-immortalized cells, and undifferentiated and differentiated human embryonic stem cells. Expression of HERV-HX2 was specifically upregulated in continuously-dividing cells, such as cancer cells and SV40-immortalized cells. Especially, HERV-HX2 in HeLa cells was highly upregulated during the S phase of the cell cycle. Similar results were obtained in hES cells, in which undifferentiated cells expressed more HERV-HX2 mRNA than differentiated hES cells, including neural precursor and endothelial progenitor cells. Taken together, our results suggest that HERV-HX2 is upregulated in cancer cells and undifferentiated hES cells, whereas downregulated as differentiation progress. Therefore, we assume that HERV-HX2 may playa role on proliferation of cancer cells as well as differentiation of hES cells in the transcriptional level.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.7
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• pp.3079-3081
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• 2015

Cancer-testis antigens (CTAs) are a group of tumor associated antigens with a restricted expression pattern in normal gametogenic tissues but expression in a broad range of malignancies. Their expression pattern has made them potential targets for immunotherapy. However, expression of some of these antigens has been demonstrated in normal stem cells as well as cancer stem cells (CSCs). As CSCs have been shown to be sources of metastasis and tumor recurrence, novel therapies are being focused on their eradication. On the other hand, CTA expression in normal stem cells raises the possibility that CTA based immunotherapies cause side effects in normal tissues.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.3
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• pp.761-766
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• 2012

Objective: Although various human cancer stem cells (CSCs) have been defined, their applications are restricted to immunocompromised models. Developing a novel CSC model which could be used in immunocompetent or transgenic mice is essential for further understanding of the biomolecular characteristics of tumor stem cells. Therefore, in this study, we analyzed murine lung cancer cells for the presence of CSCs. Methods: Side population (SP) cells were isolated by fluorescence activated cell sorting, followed by serum-free medium (SFM) culture, using Lewis lung carcinoma cell (LLC) line. The self-renewal, differentiated progeny, chemosensitivity, and tumorigenic properties in SP and non-SP cells were investigated through in vitro culture and in vivo serial transplantation. Differential expression profiles of stem cell markers were examined by RT-PCR. Results: The SP cell fraction comprised 1.1% of the total LLC population. SP cells were available to grow in SFM, and had significantly enhanced capacity for cell proliferation and colony formation. They were also more resistant to cisplatin in comparison to non-SP cells, and displayed increased tumorigenic ability. Moreover, SP cells showed higher mRNA expression of Oct-4, ABCG2, and CD44. Conclusion: We identified SP cells from a murine lung carcinoma, which possess well-known characteristics of CSCs. Our study established a useful model that should allow investigation of the biological features and pharmacosensitivity of lung CSCs, both in vitro and in syngeneic immunocompetent or transgenic/knockout mice.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.12
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• pp.5947-5954
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• 2012

The cancer stem cell (CSC) model states that cancers are organized in cellular hierarchies, which explains the functional heterogeneity often seen in tumors. Like normal tissue stem cells, CSCs are capable of self-renewal, either by symmetric or asymmetric cell division, and have the exclusive ability to reproduce malignant tumors indefinitely. Current systemic cancer therapies frequently fail to eliminate advanced tumors, which may be due to their inability to effectively target CSC populations. It has been shown that embryonic pathways such as Wnt, Hedgehog, and Notch control self-renewal and cell fate decisions of stem cells and progenitor cells. These are evolutionary conserved pathways, involved in CSC maintenance. Targeting these pathways may be effective in eradicating CSCs and preventing chemotherapy or radiotherapy resistance.

• Journal of Ginseng Research
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• v.43 no.3
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• pp.421-430
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• 2019

Background: The ginsenoside Rg3, one of active components of red ginseng, has chemopreventive and anticancer potential. Cancer stem cells retain self-renewal properties which account for cancer recurrence and resistance to anticancer therapy. In our present study, we investigated whether the standardized Korean Red Ginseng extract (RGE) and Rg3 could modulate the manifestation of breast cancer stem cell-like features through regulation of self-renewal activity. Methods: The effects of RGE and Rg3 on the proportion of $CD44^{high}/CD24^{low}$ cells, as representative characteristics of stem-like breast cancer cells, were determined by flow cytometry. The mammosphere formation assay was performed to assess self-renewal capacities of breast cancer cells. Aldehyde dehydrogenase activity of MCF-7 mammospheres was measured by the ALDEFLUOR assay. The expression levels of Sox-2, Bmi-1, and P-Akt and the nuclear localization of hypoxia inducible $factor-1{\alpha}$ in MCF-7 mammospheres were verified by immunoblot analysis. Results: Both RGE and Rg3 decreased the viability of breast cancer cells and significantly reduced the populations of $CD44^{high}/CD24^{low}$ in MDA-MB-231 cells. RGE and Rg3 treatment attenuated the expression of Sox-2 and Bmi-1 by inhibiting the nuclear localization of hypoxia inducible $factor-1{\alpha}$ in MCF-7 mammospheres. Suppression of the manifestation of breast cancer stem cell-like properties by Rg3 was mediated through the blockade of Akt-mediated self-renewal signaling. Conclusion: This study suggests that Rg3 has a therapeutic potential targeting breast cancer stem cells.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.6
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• pp.2973-2978
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• 2012

Background: Cancer stem cells (CSC) have been described in a variety of malignancies, including breast carcinomas. Among several markers, aldehyde dehydrogenase 1 (ALDH1) has been identified as reliable for breast cancer stem cells. Knockdown of BRCA1 in primary breast epithelial cells leads to an increase in cells expressing ALDH1. Methods: We examined 127 breast carcinomas for expression of ALDH1, using immunohistochemistry and correlated with clinicopathological parameters as well as the BRAC1 status. Results: Comparing the results for both ALDH1 and BRCA1 expression showed a significant inverse association between the two, indicating that reduced BRCA1 was more often seen in breast cancer cells expressing ALDH1 (p-value = 0.044). A total of 24/110 (22%) of tumours displayed the ALDH1 + / BRCA1 -/low phenotype, which showed a trend for a relation with a high grade (p-value= 0.056). Cytoplasmic expression of ALDH1 was not correlated with tumour characteristics. Conclusion: Taken together, our findings suggest that increased ALDH1 is inversely correlated with decreased BRCA1 in a series of unselected breast carcinomas. Therefore, ALDH1 positive (cancer stem) cells with reduced BRCA1 phenotype may indicate a subset of patients for whom specific targeting of the CSC marker ALDH1 and more aggressive adjuvant treatment is appropriate.

• Journal of Yeungnam Medical Science
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• v.32 no.1
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• pp.1-7
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• 2015

Over several decades, a hierarchical cancer stem cell (CSC) model has been established in development of solid cancers, including hepatocellular carcinoma(HCC). In terms of this concept, HCCs originate from liver CSCs. Clinically HCCs show a wide range of manifestations from slow growth to very aggressive metastasis. One of the reasons may be that liver CSCs originate from different cells. This review describes the basic concept of CSCs and the cellular origin of liver CSCs.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.8549-8556
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• 2014

Head and neck squamous cell carcinoma (HNSCC) is one of the world top ten most common cancers with its highest occurrence in the Indian subcontinent and different aggressive and etiological behavioural patterns. The scenario is only getting worst with the 5 year survival rates dropping to 50%, persistent treatment failures and frequent cases of relapse/recurrence. One of the major reasons for these failures is the presence of cancer stem cells (CSCs), a small population of cancer cells that are highly tumourigenic, capable of self-renewal and have the ability to differentiate into cells that constitute the bulk of tumours. Notably, recent evidence suggests that cancer stem cells are especially resistant to conventional therapy and are the "drivers" of local recurrence and metastatic spread. Specific markers for this population have been investigated in HNSCC in the hope of developing a deeper understanding of their role in oral cancer pathogenesis, elucidating novel biomarkers for early diagnosis and newer therapeutic strategies. This review covers the fundamental relevance of almost all the CSC biomarkers established to date with a special emphasis on their impact in the process of oral tumourigenesis and their potential role in improving the diagnosis, prognosis and treatment of OSCC patients.