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Cancer stem‑like cells (CSCs), which possess the ability to self‑renewal and are multipotent, are regarded as the cause of tumor formation, recurrence, metastasis and drug resistance. It is necessary to understand the properties of CSCs in order to treat them effectively. It has been previously reported that S100 family proteins, which carry calcium‑binding EF‑hand motifs and are associated with tumorigenic processes, serve crucial roles in maintaining cancer stem‑like properties. S100A16 is upregulated in various types of cancer, including bladder, lung and pancreatic. However, the roles of S100A16 in cancer cells, particularly CSCs, are not clear. The present study investigated the roles of S100A16 in CSCs using the sphere formation assay of Yumoto cells, which are a human cervical carcinoma cell line. The mRNA expression levels were evaluated by reverse transcription‑polymerase chain reaction and the protein expression levels were detected by western blot analysis. Following the sphere formation of Yumoto cells, the mRNA and protein expression level of Oct4, Nanog and S100A16 were increased compared with the control cells. Following transfection with S100A16 small interfering RNA (siRNA), the mRNA and protein expression of Oct4 and Nanog were decreased and the spheroid size was significantly decreased in the sphere formation of Yumoto cells compared with control siRNA treated cells. There was no change in the p53 mRNA expression level, whereas the p53 protein expression level, which was decreased by the sphere formation, was recovered by S100A16 knockdown. In addition, the protein expression levels of Oct4 and Nanog, which were increased in the sphere formation, were decreased by the proteasome inhibitor lactacystin. No differences were observed in the S100A16 protein expression between the presence or absence of lactacystin. These results suggest that S100A16 serves an important role in the CSCs of human cervical carcinoma and is a positive regulator of Oct4 and Nanog. [ABSTRACT FROM AUTHOR]

pluripotency of embryonic stem cells. However, the effect of ID1 on the stemness and cancer stem cell (CSC)-like properties of gastric adenocarcinoma cells remains to be elucidated. In the present study, effective ID1 knockdown was achieved in gastric cancer (GC) cells using small interfering RNA, and the self-renewal ability and cisplatin (DDP) sensitivity of GC cells was subsequently examined. ID1 knockdown in the MKN-28 and MGC-803 cell lines was demonstrated to significantly suppress colony formation (P=0.005 in MKN-28 and P=0.001 in MGC-803), tumor spheroid formation (P=0.021 in MKN-28 and P=0.037 in MGC-803), cell proliferation (P=0.028 in MKN-28 and P=0.001 in MGC-803) and migration (P=0.002 in MKN-28 and P=0.015 in MGC-803). To the best of our knowledge, the present study revealed for the first time that ID1 knockdown suppresses the expression of the key CSC-associated factors Nanog and octamer-binding protein 4 (Oct-4). It was further demonstrated that ID1 knockdown sensitized GC cells to DDP. In conclusion, knockdown of ID1 attenuates the stem cell like-properties of self-renewal in normal GC cells, potentially through the targeting of Nanog and Oct-4, and subsequently decreases cell proliferation and resistance to DDP. The results of the present study suggest that ID1 functions as an oncogene in GC and regulates the stem cell like-properties of gastric cancer cells by targeting Nanog and Oct-4. [ABSTRACT FROM AUTHOR]

The present study aimed to determine the expression of stem cell markers Nanog compared with PSCA in gastric cancer tissues and adjacent normal tissues, and to investigate the association between tumor stem cells and initiation, progression, metastasis, and prognosis of gastric cancer. One hundred chemotherapy- and radiotherapy-naive patients with pathologically confirmed gastric cancer were enrolled from the General Surgery Department and Surgical Oncology Department of the Affiliated Hospital of Inner Mongolia Medical University (Hohhot, P.R. China), between October 2011 and June 2013. Surgically resected specimens of cancer tissues and adjacent normal tissues (>5 cm from the boundary of cancerous component) were collected. The mRNA expression levels of Nanog and PSCA in those tissues was determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The correlation between the expression of stem cell markers Nanog and PSCA in gastric cancer tissues and clinicopathological factors was analyzed. The qPCR results demonstrated that the relative expression of Nanog was increased in gastric cancer tissues compared with in the adjacent tissues (P<0.05); and relative expression of PSCA was reduced in gastric cancer tissues compared with adjacent tissues (P<0.05). The expression of Nanog and PSCA in gastric cancer tissues was associated with tumor differentiation. The expression of Nanog was increased in poorly-differentiated and undifferentiated tumors compared with moderately- and well-differentiated tumors (P<0.05). The expression of PSCA was reduced in poorly differentiated and undifferentiated tumors compared with moderately- and well-differentiated tumors (P<0.05). However, the expression of Nanog and PSCA was not associated with age, gender, tumor size, TNM stage, depth of invasion, or lymph node metastasis. Therefore, Nanog and PSCA may have potential as molecular markers to reflect the differentiation status of gastric cancer. [ABSTRACT FROM AUTHOR]

Doublecortin-like kinase 1 (DCLK1), a microtubule- associated protein, is known to regulate neuronal differentiation, migration and neurogenesis. Recent evidence suggests that the protein is a putative marker for intestinal and pancreatic stem cells, including their cancer stem cell counterparts. The present study conducted immunohistochemical analyses for DCLK1 and the stemness marker, NANOG, in human intestinal neuroendocrine tumors (NETs), as their expression had not been previously investigated in these tumors. Eighteen patients with endoscopically resected rectal NETs were enrolled in the study. The mean age of the patients was 51 years old. The mean diameter of the resected tumors was 5.2 mm, and a histological diagnosis of NET grade G1 was formed for all tumors. Immunohistochemical analysis was performed not only for DCLK1, but also for the known NET markers, synaptophysin, chromogranin A and cluster of differentiation (CD)56. The intensity and distribution of staining were scored on a scale of 0-3 and 0-2, respectively. The sum of the scores was calculated for each specimen. Co-expression of DCLK1 and NANOG was also examined. The mean scores for DCLK1 and synaptophysin were significantly higher than those for chromogranin A (P<0.0001) and CD56 (P<0.01). There were no significant differences in the scores between DCLK1 and synaptophysin or between chromogranin A and CD56. Notably, NANOG was expressed in high quantities in all the tumor tissues studied, showing clear co-expression with DCLK1. In conclusion, DCLK1 may be a novel marker for rectal NET, potentially indicating the presence of the stemness gene product, NANOG. [ABSTRACT FROM AUTHOR]

Cancer stem cells (CSCs) have been identified in a variety of cancer types, including prostate cancer. The aim of the present study was to evaluate the immunohistochemical expression of NANOG, octamer 4 (OCT4), cluster of differentiation 133 (CD133) and NESTIN, which are all CSC markers, and assess their function in prostate carcinogenesis. A total of 114 patients were referred to the Kanazawa Medical University Hospital (Uchinada, Japan) having presented with elevated serum prostate-specific antigen levels and/or abnormal digital rectal examinations, and underwent transrectal ultrasound sonography guided eight core biopsies. The prostate pathological specimens were re-evaluated for selection in this study. When specimens were diagnosed as prostate cancer, immunohistochemical analysis of the four different stem cell markers (NANOG, OCT4, CD133 and NESTIN) and hypoxia-inducible factor (HIF)-1α was performed. Prostate cancer was found in 38 cases (33.3%), while the other patients had benign prostate hyperplasia with prostatitis. All prostate cancers were histopathologically identified as adenocarcinomas of various grades, and cancer cells and intraepithelial neoplasia (high grade) were immunohistochemically shown to express NANOG and OCT4, but not CD133 and NESTIN. The intensity of NANOG expression was much greater than that of OCT4, and the positivity and intensity of the four stem cell markers, including NANOG, were elevated with high Gleason scores. A significant correlation was observed between the NANOG- and HIF-1α-positive regions. The CSC markers, in particular OCT4 and NANOG, were immunohistochemically expressed in prostate cancers. Furthermore, HIF-1α expression may affect NANOG and/or OCT4 expression. The findings of the current study suggested that NANOG expression may be a biomarker for the diagnosis of prostate cancer, and the coexpression of NANOG and HIF-1α may be involved in prostate carcinogenesis. [ABSTRACT FROM AUTHOR]

NANOG protein, a transcription factor expressed in embryonic stem cells, is overexpressed in tumor development. Although studies investigating the function of NANOG in cancer have shown that it plays several roles, such as in cell proliferation, invasion and metastasis, the overall function of NANOG in cancer cells has remained elusive. In the present study, NANOG expression in oral squamous cell carcinoma (OSCC) was examined to determine its potential clinical significance. The expression of NANOG protein was assessed in 60 patients with OSCC by immunohistochem-istry, and its correlation with clinicopathological factors and metastasis was evaluated. NANOG protein levels in human OSCC cell lines were determined by western blotting and immunofluorescence staining. NANOG protein expression was identified in 52 cases (86.7%) and expression levels were higher in primary foci of poorly differentiated OSCC than in those of well-differentiated OSCC, indicating that NANOG expression is associated with OSCC differentiation. Regardless of the differentiation levels of primary foci, NANOG expression levels in metastatic foci were extremely high. In addition, NANOG expression in metastatic foci was maintained at high levels following preoperative adjuvant therapy. Furthermore, NANOG protein was detected at an identical level in human OSCC cell lines. These data indicate that NANOG-expressing OSCC cells tend to metastasize and that metastatic tumors expressing NANOG may be resistant to preoperative adjuvant therapy, including chemoradiation. Thus, assessment of NANOG expression may assist the strategy for treatment of OSCC metastasis. [ABSTRACT FROM AUTHOR]

DNA-binding protein inhibitor ID-1 (ID1) serves an essential role in tumor progression, and the self-renewal and pluripotency of embryonic stem cells. However, the effect of ID1 on the stemness and cancer stem cell (CSC)-like properties of gastric adenocarcinoma cells remains to be elucidated. In the present study, effective ID1 knockdown was achieved in gastric cancer (GC) cells using small interfering RNA, and the self-renewal ability and cisplatin (DDP) sensitivity of GC cells was subsequently examined. ID1 knockdown in the MKN-28 and MGC-803 cell lines was demonstrated to significantly suppress colony formation (P=0.005 in MKN-28 and P=0.001 in MGC-803), tumor spheroid formation (P=0.021 in MKN-28 and P=0.037 in MGC-803), cell proliferation (P=0.028 in MKN-28 and P=0.001 in MGC-803) and migration (P=0.002 in MKN-28 and P=0.015 in MGC-803). To the best of our knowledge, the present study revealed for the first time that ID1 knockdown suppresses the expression of the key CSC-associated factors Nanog and octamer-binding protein 4 (Oct-4). It was further demonstrated that ID1 knockdown sensitized GC cells to DDP. In conclusion, knockdown of ID1 attenuates the stem cell like-properties of self-renewal in normal GC cells, potentially through the targeting of Nanog and Oct-4, and subsequently decreases cell proliferation and resistance to DDP. The results of the present study suggest that ID1 functions as an oncogene in GC and regulates the stem cell like-properties of gastric cancer cells by targeting Nanog and Oct-4.

The present study aimed to determine the expression of stem cell markers Nanog compared with PSCA in gastric cancer tissues and adjacent normal tissues, and to investigate the association between tumor stem cells and initiation, progression, metastasis, and prognosis of gastric cancer. One hundred chemotherapy- and radiotherapy-naive patients with pathologically confirmed gastric cancer were enrolled from the General Surgery Department and Surgical Oncology Department of the Affiliated Hospital of Inner Mongolia Medical University (Hohhot, P.R. China), between October 2011 and June 2013. Surgically resected specimens of cancer tissues and adjacent normal tissues (>5 cm from the boundary of cancerous component) were collected. The mRNA expression levels of Nanog and PSCA in those tissues was determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The correlation between the expression of stem cell markers Nanog and PSCA in gastric cancer tissues and clinicopathological factors was analyzed. The qPCR results demonstrated that the relative expression of Nanog was increased in gastric cancer tissues compared with in the adjacent tissues (P<0.05); and relative expression of PSCA was reduced in gastric cancer tissues compared with adjacent tissues (P<0.05). The expression of Nanog and PSCA in gastric cancer tissues was associated with tumor differentiation. The expression of Nanog was increased in poorly-differentiated and undifferentiated tumors compared with moderately- and well-differentiated tumors (P<0.05). The expression of PSCA was reduced in poorly differentiated and undifferentiated tumors compared with moderately- and well-differentiated tumors (P<0.05). However, the expression of Nanog and PSCA was not associated with age, gender, tumor size, TNM stage, depth of invasion, or lymph node metastasis. Therefore, Nanog and PSCA may have potential as molecular markers to reflect the differentiation status of gastric cancer.

Doublecortin-like kinase 1 (DCLK1), a microtubule-associated protein, is known to regulate neuronal differentiation, migration and neurogenesis. Recent evidence suggests that the protein is a putative marker for intestinal and pancreatic stem cells, including their cancer stem cell counterparts. The present study conducted immunohistochemical analyses for DCLK1 and the stemness marker, NANOG, in human intestinal neuroendocrine tumors (NETs), as their expression had not been previously investigated in these tumors. Eighteen patients with endoscopically resected rectal NETs were enrolled in the study. The mean age of the patients was 51 years old. The mean diameter of the resected tumors was 5.2 mm, and a histological diagnosis of NET grade G1 was formed for all tumors. Immunohistochemical analysis was performed not only for DCLK1, but also for the known NET markers, synaptophysin, chromogranin A and cluster of differentiation (CD)56. The intensity and distribution of staining were scored on a scale of 0-3 and 0-2, respectively. The sum of the scores was calculated for each specimen. Co-expression of DCLK1 and NANOG was also examined. The mean scores for DCLK1 and synaptophysin were significantly higher than those for chromogranin A (P<0.0001) and CD56 (P<0.01). There were no significant differences in the scores between DCLK1 and synaptophysin or between chromogranin A and CD56. Notably, NANOG was expressed in high quantities in all the tumor tissues studied, showing clear co-expression with DCLK1. In conclusion, DCLK1 may be a novel marker for rectal NET, potentially indicating the presence of the stemness gene product, NANOG.

Cancer stem cells (CSCs) have been identified in a variety of cancer types, including prostate cancer. The aim of the present study was to evaluate the immunohistochemical expression of NANOG, octamer 4 (OCT4), cluster of differentiation 133 (CD133) and NESTIN, which are all CSC markers, and assess their function in prostate carcinogenesis. A total of 114 patients were referred to the Kanazawa Medical University Hospital (Uchinada, Japan) having presented with elevated serum prostate-specific antigen levels and/or abnormal digital rectal examinations, and underwent transrectal ultrasound sonography guided eight core biopsies. The prostate pathological specimens were re-evaluated for selection in this study. When specimens were diagnosed as prostate cancer, immunohistochemical analysis of the four different stem cell markers (NANOG, OCT4, CD133 and NESTIN) and hypoxia-inducible factor (HIF)-1α was performed. Prostate cancer was found in 38 cases (33.3%), while the other patients had benign prostate hyperplasia with prostatitis. All prostate cancers were histopathologically identified as adenocarcinomas of various grades, and cancer cells and intraepithelial neoplasia (high grade) were immunohistochemically shown to express NANOG and OCT4, but not CD133 and NESTIN. The intensity of NANOG expression was much greater than that of OCT4, and the positivity and intensity of the four stem cell markers, including NANOG, were elevated with high Gleason scores. A significant correlation was observed between the NANOG- and HIF-1α-positive regions. The CSC markers, in particular OCT4 and NANOG, were immunohistochemically expressed in prostate cancers. Furthermore, HIF-1α expression may affect NANOG and/or OCT4 expression. The findings of the current study suggested that NANOG expression may be a biomarker for the diagnosis of prostate cancer, and the coexpression of NANOG and HIF-1α may be involved in prostate carcinogenesis.

NANOG protein, a transcription factor expressed in embryonic stem cells, is overexpressed in tumor development. Although studies investigating the function of NANOG in cancer have shown that it plays several roles, such as in cell proliferation, invasion and metastasis, the overall function of NANOG in cancer cells has remained elusive. In the present study, NANOG expression in oral squamous cell carcinoma (OSCC) was examined to determine its potential clinical significance. The expression of NANOG protein was assessed in 60 patients with OSCC by immunohistochemistry, and its correlation with clinicopathological factors and metastasis was evaluated. NANOG protein levels in human OSCC cell lines were determined by western blotting and immunofluorescence staining. NANOG protein expression was identified in 52 cases (86.7%) and expression levels were higher in primary foci of poorly differentiated OSCC than in those of well-differentiated OSCC, indicating that NANOG expression is associated with OSCC differentiation. Regardless of the differentiation levels of primary foci, NANOG expression levels in metastatic foci were extremely high. In addition, NANOG expression in metastatic foci was maintained at high levels following preoperative adjuvant therapy. Furthermore, NANOG protein was detected at an identical level in human OSCC cell lines. These data indicate that NANOG-expressing OSCC cells tend to metastasize and that metastatic tumors expressing NANOG may be resistant to preoperative adjuvant therapy, including chemoradiation. Thus, assessment of NANOG expression may assist the strategy for treatment of OSCC metastasis.

The aim of the present study was to employ RNA interference (RNAi) technology to construct and select shRNA-Nanog recombinant plasmids for the inhibition of Nanog gene expression and transfer these plasmids into the human gastric cancer cell line, SGC-7901, as well as to detect the expression of Nanog and the effects on the proliferation, migration, invasion, cell cycle and apoptosis of SGC-7901 cells. The pshRNA-Nanog interference plasmids were constructed and used to transfect SGC-7901 cells using lipofectamine. The expression of the Nanog gene was detected by fluorescence microscopy, RT-PCR and western blotting, and the most markedly inhibited group was identified. The SGC-7901 cells were transfected with recombinant shRNA-Nanog plasmids from the most markedly inhibited group using lipofectamine and the effect on proliferation was determined by CCK-8 assay. The migration and invasion of the SGC-7901 cells was determined by Transwell assays, while the cell cycle and apoptosis were analyzed by flow cytometry. The group with the highest inhibition rate was successfully constructed and identified. It was observed that the proliferation, invasion and migration capacity of the cells was reduced, that the cell cycle was arrested at the S phase and that apoptosis was significantly increased. The Nanog gene in gastric cancer cells is closely associated with cell proliferation, the cell cycle, apoptosis and migration and invasion abilities. The present study establishes the foundations for a novel approach for the genetic treatment of gastric cancer.