• Nutrition Research and Practice
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• 제16권2호
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• pp.161-172
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• 2022

BACKGROUND/OBJECTIVES: Colorectal cancer (CRC) is the third most common cancer worldwide and has a high recurrence rate, which is associated with cancer stem cells (CSCs). β-carotene (BC) possesses antioxidant activity and several anticancer mechanisms. However, no investigation has examined its effect on colon cancer stemness. MATERIALS/METHODS: CD133⁺CD44⁺ HCT116 and CD133⁺CD44⁺ HT-29 cells were isolated and analyzed their self-renewal capacity by clonogenic and sphere formation assays. Expressions of several CSCs markers and Wnt/β-catenin signaling were examined. In addition, CD133⁺CD44⁺ HCT116 cells were subcutaneously injected in xenograft mice and analyzed the effect of BC on tumor formation, tumor volume, and CSCs markers in tumors. RESULTS: BC inhibited self-renewal capacity and CSC markers, including CD44, CD133, ALDH1A1, NOTCH1, Sox2, and β-catenin in vitro. The effects of BC on CSC markers were confirmed in primary cells isolated from human CRC tumors. BC supplementation decreased the number and size of tumors and delayed the tumor-onset time in xenograft mice injected with CD133⁺CD44⁺ HCT116 cells. The inhibitory effect of BC on CSC markers and the Wnt/β-catenin signaling pathway in tumors was confirmed in vivo as well. CONCLUSIONS: These results suggest that BC may be a potential therapeutic agent for colon cancer by targeting colon CSCs.

• Biomolecules & Therapeutics
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• 제24권5호
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• pp.482-488
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• 2016

Cancer stem cells (CSCs) are a subset of tumor cells, which are characterized by resistance against chemotherapy and environmental stress, and are known to cause tumor relapse after therapy. A number of molecular mechanisms underlie the chemoresistance of CSCs, including high expression levels of drug efflux transporters. We investigated the role of the antioxidant transcription factor NF-E2-related factor 2 (NRF2) in chemoresistance development, using a CSC-enriched colonosphere system. HCT116 colonospheres were more resistant to doxorubicin-induced cell death and expressed higher levels of drug efflux transporters such as P-glycoprotein (Pgp) and breast cancer resistance protein (BCRP) compared to HCT116 monolayers. Notably, levels of NRF2 and expression of its target genes were substantially elevated in colonospheres, and these increases were linked to doxorubicin resistance. When NRF2 expression was silenced in colonospheres, Pgp and BCRP expression was downregulated, and doxorubicin resistance was diminished. Collectively, these results indicate that NRF2 activation contributes to chemoresistance acquisition in CSC-enriched colonospheres through the upregulation of drug efflux transporters.

• Asian Pacific Journal of Cancer Prevention
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• 제16권9호
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• pp.3629-3633
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• 2015

Cancer stem cells (CSCs) are rare subpopulations within tumors which are recognized as culprits in cancer recurrence, drug resistance and metastasis. However, the molecular mechanisms of how CSCs are regulated remain elusive. Kr$\ddot{u}$ppel-like factors (KLFs) are evolutionarily conserved zinc finger-containing transcription factors with diverse functions in cell differentiation, proliferation, embryogenesis and pluripotency. Recent progress has highlighted the significance of KLFs, especially KLF4, in cancer and CSCs. Therefore, for better therapeutics of cancer disease, it is crucial to develop a deeper understanding of the mechanisms of how KLF4 regulate CSC functions. Herein we summarized the current understanding of the transcriptional regulation of K LF4 in CSCs, and discussed the functional implications of targeting CSCs for potential cancer therapeutics.

• BMB Reports
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• 제55권2호
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• pp.98-103
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• 2022

Increased mRNA levels of cancer upregulated gene (CUG)2 have been detected in many different tumor tissues using Affymetrix microarray. Oncogenic capability of the CUG2 gene has been further reported. However, the mechanism by which CUG2 overexpression promotes cancer stem cell (CSC)-like phenotypes remains unknown. With recent studies showing that pyruvate kinase muscle 2 (PKM2) is overexpressed in clinical tissues from gastric, lung, and cervical cancer patients, we hypothesized that PKM2 might play an important role in CSC-like phenotypes caused by CUG2 overexpression. The present study revealed that PKM2 protein levels and translocation of PKM2 into the nucleus were enhanced in CUG2-overexpressing lung carcinoma A549 and immortalized bronchial BEAS-2B cells than in control cells. Expression levels of c-Myc, CyclinD1, and PKM2 were increased in CUG2-overexpressing cells than in control cells. Furthermore, EGFR and ERK inhibitors as well as suppression of Yap1 and NEK2 expression reduced PKM2 protein levels. Interestingly, knockdown of β-catenin expression failed to reduce PKM2 protein levels. Furthermore, reduction of PKM2 expression with its siRNA hindered CSC-like phenotypes such as faster wound healing, aggressive transwell migration, and increased size/number of sphere formation. The introduction of mutant S37A PKM2-green fluorescence protein (GFP) into cells without ability to move to the nucleus did not confer CSC-like phenotypes, whereas forced expression of wild-type PKM2 promoted such phenotypes. Overall, CUG2-induced increase in the expression of nuclear PKM2 contributes to CSC-like phenotypes by upregulating c-Myc and CyclinD1 as a co-activator.

• Asian Pacific Journal of Cancer Prevention
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• 제15권20호
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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.

• BMB Reports
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• 제51권11호
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• pp.596-601
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• 2018

Colon cancer is one of the most lethal and common malignancies worldwide. STK899704, a novel synthetic agent, has been reported to exhibit anticancer effects towards numerous cancer cells. However, the effect of STK899704 on the biological properties of colon cancer, including cancer cell migration and cancer stem cells (CSCs), remains unknown. Here, we examined the inhibitory effect of STK899704 on cell migration and CSC stemness. In the wound healing assay, STK899704 significantly inhibited the motility of colon cancer cells. Furthermore, STK899704 downregulated the mRNA expression levels of the cell migration mediator focal adhesion kinase (FAK). STK899704 also suppressed mitogen-activated protein kinase kinase and extracellular signal-regulated kinase, which are downstream signaling molecules of FAK. Additionally, STK899704 inhibited stemness gene expression and sphere formation in colon cancer stem cells. These results suggest that STK899704 can be used to treat human colon cancer.

• The Korean Journal of Physiology and Pharmacology
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• 제16권1호
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• pp.11-16
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• 2012

Cancer stem cells (CSCs) are often characterized by the elevated expression of drug-resistance related stem-cell surface markers, such as CD133 and ABCG2. Recently, we reported that CSCs have a high level of expression of the IL-6 receptor (IL-6R). The purpose of this study was to investigate the effect of anticancer drugs on the expression of the drug resistance-related cancer stem cell markers, ABCG2, IL-6R, and CD133 in non-small cell lung cancer (NSCLC) cell lines. A549, H460, and H23 NSCLC cell lines were treated with the anticancer drugs 5-fluorouracil (5-FU; $25{\mu}g/ml$) and methotrexate (MTX; $50{\mu}g/ml$), and the expression of putative CSC markers was analyzed by fluorescent activated cell sorter (FACS) and the gene expression level of abcg2, il-6r and cd133 by reverse transcriptase-polymerase chain reaction (RT-PCR). We found that the fraction of ABCG2-positive(+) cells was significantly increased by treatment with both 5-FU and MTX in NSCLC cells, and the elevation of abcg2, il-6r and cd133 expressions in response to these drugs was also confirmed using RT-PCR. Also, the number of IL-6R(+) cells was increased by MTX in the 3 cell lines mentioned and increased by 5-FU in the H460 cell line. The number of CD133(+) cells was also significantly increased by both 5-FU and MTX treatment in all of the cell lines tested. These results indicate that 5-FU and MTX considerably enhance the expression of drug-resistance related CSC markers in NSCLC cell lines. Thus, we suggest that antimetabolite cancer drugs, such as 5-FU and MTX, can lead to the propagation of CSCs through altering the expression of CSC markers.

• Asian Pacific Journal of Cancer Prevention
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• 제13권3호
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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.

• 대한수의학회지
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• 제58권4호
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• pp.201-209
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• 2018

Canine mammary tumors are among the most frequently observed cutaneous tumors in female dogs. Cancer stem cells (CSCs), referred to as tumor-initiating cells, are thought to have properties similar to normal stem cells such as the ability to self-renewal and to differentiate into various cell types. Biological understanding of CSCs and the critical pathways involved in their maintenance are important in research and therapy for mammary tumors. We conducted the present study on sphere formation from REM134 cells by using methylcellulose to produce tumorspheres on a large scale and compared the specific markers of the spheres-formed and plating-cultured REM134 cells. The results revealed that the tumorspheres cultured in methylcellulose had higher seeding density and improved morphology compared to those produced in normal sphere formation medium. Expression levels of stemness markers and CSC-related markers were higher in tumorsphere-forming cells than in plating-cultured cells. Subsequently, we transplanted the tumorsphere-forming and plating-cultured cells into female nude mice to examine their tumorigenic potential. Tumor volume increased rapidly in mice transplanted with tumorsphere-derived cells compared to plating-cultured cells. We observed a novel sphere-forming condition for REM134 cells and showed that REM134 cell tumorspheres can exhibit improved CSC properties.

• Molecules and Cells
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• 제40권11호
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• pp.847-854
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• 2017

Recent studies on molecular carcinogenesis suggest that the chemo-resistance of some cancers is largely due to presence of cancer stem cells (CSCs), which affect the chemotherapy outcome for hepatocellular carcinoma (HCC). However, currently no consensus on a CSC phenotype in HCC has been obtained. Here, we examined Sox12 as a novel CSC marker in HCC. Sox12+ versus Sox12- cells were purified from HCC cell lines. The Sox12+ cells were compared with Sox12- HCC cells for tumor sphere formation, chemo-resistance, tumor formation after serial adoptive transplantations in nude mice, and the frequency of developing distal metastasis. We found that compared to Sox12- HCC cells, Sox12+ HCC cells generated significantly more tumor spheres in culture, were more chemo-resistant to cisplatin, were detected in circulation more frequently, and formed distal tumor more frequently. Moreover, Sox12 appeared to functionally contribute to the stemness of HCC cells. Thus, we conclude that Sox12 may be a novel marker for enriching CSCs in HCC.