Cancer Stem Cell Markers CD44 Research Articles

Cancer Stem Cell Markers in Rhabdomyosarcoma in Children.

(1) Background: The aim of the present study was to assess the cancer stem cell (CSC) markers CD24, CD44, CD133, and ALDH1A1 in rhabdomyosarcoma (RMS) in children and to define their prognostic role in this group of patients. (2) Methods: The study material was archival tissue specimens collected from 49 patients under 18 years of age and who had been diagnosed with RMS. Immunohistochemistry (IHC) was used to evaluate the expression of the selected CSC markers in the tumor tissue. Expression was evaluated using a semiquantitative IRS scale based on the one developed by Remmele and Stenger and was correlated with the clinical and pathomorphological parameters of prognostic importance in RMS. (3) Results: Expression of the selected CSC markers CD24, CD44, CD133, and ALDH1A1 was demonstrated in 83.7%, 55.1%, 81.6%, and 100% of the RMS patients, respectively. The expression of all of the assessed CSC markers was statistically significantly higher in the study group versus the control group. No significant correlation was found between the expression of the selected CSC markers and clinical and pathological prognostic factors that were analyzed. The expression of the CSC markers did not have a significant influence on RMS survival rates. (4) Conclusions: The results of the conducted study confirm the expression of selected CSC markers in rhabdomyosarcoma tissue in children. The study did not support the prognostic relevance of the expression of any of the assessed CSC markers. However, further studies are needed to fully understand the relevance of the selected CSC markers in RMS carcinogenesis.

PFKFB3 regulates cancer stemness through the hippo pathway in small cell lung carcinoma

PFKFB3 (6-phosphofructo-2-kinase) is the rate-limiting enzyme of glycolysis and is overexpressed in several human cancers that are associated with poor prognosis. High PFKFB3 expression in cancer stem cells promotes glycolysis and survival in the tumor microenvironment. Inhibition of PFKFB3 by the glycolytic inhibitor PFK158 and by shRNA stable knockdown in small cell lung carcinoma (SCLC) cell lines inhibited glycolysis, proliferation, spheroid formation, and the expression of cancer stem cell markers CD133, Aldh1, CD44, Sox2, and ABCG2. These factors are also associated with chemotherapy resistance. We found that PFK158 treatment and PFKFB3 knockdown enhanced the ABCG2-interacting drugs doxorubicin, etoposide, and 5-fluorouracil in reducing cell viability under conditions of enriched cancer stem cells (CSC). Additionally, PFKFB3 inhibition attenuated the invasion/migration of SCLC cells by downregulating YAP/TAZ signaling while increasing pLATS1 via activation of pMST1 and NF2 and by reducing the mesenchymal protein expression. PFKFB3 knockdown and PFK158 treatment in a H1048 SCLC cancer stem cell-enriched mouse xenograft model showed significant reduction in tumor growth and weight with reduced expression of cancer stem cell markers, ABCG2, and YAP/TAZ. Our findings identify that PFKFB3 is a novel target to regulate cancer stem cells and its associated therapeutic resistance markers YAP/TAZ and ABCG2 in SCLC models.

Evodiamine inhibits stemness and metastasis by altering the SOX9-β-catenin axis in non-small-cell lung cancer.

Evodiamine (EVO), a natural dietary alkaloid extracted from the roots of the Evodia rutaecarpa, has shown anticancer activities. Here, we have investigated EVO's role in inhibiting cell proliferation and migration in A549 and NCI-H522 lung cancer cells. EVO decreased the cell viability in A549 and NCI-H522 cells in a dose- and time-dependent manner. It also induced apoptosis by downregulating the expression of antiapoptotic Bcl-2 and upregulating the expression of cleaved caspase-3 and PARP. In addition, the treatment of EVO elevated the level of reactive oxygen species (ROS) generation inside the cells to induce the cell death pathways. In contrast, the pretreatment of ROS scavenger, N-acetyl cysteine, reverses the effect of EVO and attenuates cell death. Moreover, excess ROS generation in response to EVO resulted in the depletion of mitochondrial membrane potential. Furthermore, it induced DNA damage and arrested the cell cycle at the G2/M phase in A549 and NCI-H522 cells. Our study also investigated that EVO significantly suppressed tumorigenicity by inhibiting colony formation and tumorsphere formation. However, the treatment of EVO downregulated the cancer stem cell markers CD44 and CD133 in non-small-cell lung cancer. The inhibitory effect of EVO on cell invasion was mediated by altering the expression of E-cadherin, ZO-1, N-cadherin, and Vimentin. Additionally, we have revealed that EVO treatment showed downregulation of SOX9, an upstream component of β-catenin. Lastly, we have demonstrated that EVO targets the SOX9-β-catenin axis by reducing SOX9 and β-catenin expression. These findings suggested that EVO could be a promising agent for treating human lung cancer.

Possible cytotoxic effect of allantoin on oral squamous cell carcinoma stemness (in vivo and in vitro model

Cancer stem cells (CSCs) and associated tumor microenvironment (TM) have been proposed to mediate cancer progression, and therapeutic resistance rendering them valuable therapeutic targets in head and neck squamous cell carcinomas (HNSCC). Oral CSCs drive their tumorigenic effect via stromal fibroblasts. Phytochemicals like allantoin are extensively used in wound healing modulating fibroblast activity. The present study aimed to evaluate whether allantoin can modulate CSCs and/or TM and subsequently contribute to sensitization of cancer cells to chemotherapeutic agents. Hep2, OECs, DPSC cell lines were used to test the cytotoxicity of allantoin on cancer, oral epithelial cells, and normal dental pulp stem cells, respectively. The effect of allantoin and/or 5‐fluorouracil (5FU) on cell cycle, apoptosis and expression of stem cell and apoptotic markers was tested in vitro. Further validation was performed using in vivo 4‐nitroquinoline 1‐oxide model of tongue squamous cell carcinoma model with assessment of cytotoxic effect of allantoin by flow cytometry, immunohistochemical staining, western‐blot and RT‐PCR. Allantoin was safe on both normal oral epithelial cells and dental pulp stem cells. Allantoin showed a statistically significant and dose dependent increase in 5FU apoptotic effect via reduction of cancer stem cell markers CD133 and CD44. Regarding cell cycle arrest, there was no statistically significant difference with addition of allantoin to 5FU. In vivo, allantoin down‐regulated SOX2, NANOG, ALDH and OCT4 gene expression in tongue squamous cell carcinoma. Additionally, allantoin reduced the expression IL‐6, TGF‐Β, PDGF, α‐ SMA and CD163. Our results proposed that high concentration of allantoin drives its antitumorigenic effect. This was mediated by modulating stromal component of TM via down‐regulation of trans‐differentiation of cancer associated fibroblasts and tumor associated macrophages. These findings shed the light on potential use of allantoin as cytotoxic drug either alone or combined with other chemotherapeutic drugs.

Elevated Expression of the Immune Checkpoint Ligand CD276 (B7-H3) in Urothelial Carcinoma Cell Lines Correlates Negatively with the Cell Proliferation.

The cell surface molecule CD276 (B7-H3) is an immune checkpoint antigen. The elevated expression of CD276 on tumors contributes to the suppression of anti-tumor T-cell responses and correlates with poor prognosis. Methods: The expression of CD276 was explored in vitro on eight urothelial carcinoma cell lines (UM-UC) in comparison to eight normal urothelial cells (NUCs) by RT-qPCR, Western blotting, and flow cytometry. Cell proliferation was enumerated over consecutive passages. The expression of cancer stem cell markers CD24 and CD44, cytokeratins, and vimentin was investigated by immunofluorescence. The expression of CD276 in bladder tumor samples and metastases was explored by immunohistochemistry. Results: Expression of CD276 on cell surfaces was elevated on UM-UCs when compared to NUCs. In UM-UCs, CD276 transcripts correlated moderately positive with CD276 protein expression (ρ = 0.660) and strongly positive with CD276 surface-expression (ρ = 0.810). CD276 mRNA expression (ρ = −0.475) and CD276 protein expression (ρ = −0.417) had a significant negative correlation with proliferation, while a significant correlation between proliferation and cell surface expression was not observed in UM-UCs. Conclusion: The expression of CD276 on UM-UC bladder tumor cell surfaces is elevated. Slow proliferating UM-UC cells express more CD276 mRNA and protein than fast proliferating cells. In patients, slow proliferating CD276high tumor (stem) cells may evade immune surveillance. However, cancer therapy targeting CD276 may be effective in the treatment of slow proliferating tumor cells.

Development and validation of a 6-gene signature for the prognosis of loco-regional control in patients with HPV-negative locally advanced HNSCC treated by postoperative radio(chemo)therapy

PurposeThe aim of this study was to develop and validate a novel gene signature from full-transcriptome data using machine-learning approaches to predict loco-regional control (LRC) of patients with human papilloma virus (HPV)-negative locally advanced head and neck squamous cell carcinoma (HNSCC), who received postoperative radio(chemo)therapy (PORT-C). Materials and methodsGene expression analysis was performed using Affymetrix GeneChip Human Transcriptome Array 2.0 on a multicentre retrospective training cohort of 128 patients and an independent validation cohort of 114 patients from the German Cancer Consortium - Radiation Oncology Group (DKTK-ROG). Genes were filtered based on differential gene expression analyses and Cox regression. The identified gene signature was combined with clinical parameters and with previously identified genes related to stem cells and hypoxia. Technical validation was performed using nanoString technology. ResultsWe identified a 6-gene signature consisting of four individual genes CAV1, GPX8, IGLV3-25, TGFBI, and one metagene combining the highly correlated genes INHBA and SERPINE1. This signature was prognostic for LRC on the training data (ci = 0.84) and in validation (ci = 0.63) with a significant patient stratification into two risk groups (p = 0.005). Combining the 6-gene signature with the clinical parameters T stage and tumour localisation as well as the cancer stem cell marker CD44 and the 15-gene hypoxia-associated signature improved the validation performance (ci = 0.69, p = 0.001). ConclusionWe have developed and validated a novel prognostic 6-gene signature for LRC of HNSCC patients with HPV-negative tumours treated by PORT-C. After successful prospective validation the signature can be part of clinical trials on the individualization of radiotherapy.

Expression of Cancer Stem Cell Markers CD133 and Nestin in Skin Tumors in Egyptian Patients

Expression of Cancer Stem Cell Markers CD133 and Nestin in Skin Tumors in Egyptian Patients

Biomarker signatures for primary radiochemotherapy of locally advanced HNSCC – Hypothesis generation on a multicentre cohort of the DKTK-ROG

PurposeTo develop prognostic biomarker signatures for patients with locally advanced head and neck squamous cell carcinoma (HNSCC) treated by primary radiochemotherapy (RCTx) based on previously published molecular analyses of the retrospective biomarker study of the German Cancer Consortium – Radiation Oncology Group (DKTK-ROG). Material and methodsIn previous studies on the retrospective DKTK-ROG HNSCC cohort treated with primary RCTx, the following clinical parameters and biomarkers were evaluated and found to be significantly associated with loco-regional tumour control (LRC) or overall survival (OS): tumour volume, p16 status, expression of cancer stem cell markers CD44 and SLC3A2, expressions of hypoxia-associated gene signatures, tumour mutational burden (TMB), single nucleotide polymorphisms (SNPs) in the ERCC2 gene (rs1799793, rs13181) and ERCC5 gene (rs17655) as well as the expression of CXCR4, SDF-1 and CD8. These biomarkers were combined in multivariable modelling using Cox-regression with backward variable selection. ResultsA baseline signature containing the widely accepted parameters tumour volume, p16 status, cancer stem cell marker expression (CD44), and hypoxia-associated gene expression has been defined, representing the main hypothesis of the study. Furthermore, the baseline signature was extended by additional prognostic biomarkers and a data-driven signature without any pre-hypothesis was generated for both endpoints. In these signatures, the SNPs rs1799793 and rs17655 as well as CXCR4, SDF-1 and SLC3A2 expression were additionally included. The signatures showed significant patient stratifications for LRC and OS. ConclusionThree biomarker signatures were defined for patients with locally advanced HNSCC treated with primary RCTx for the endpoints LRC and OS. These signatures will be validated in the prospective HNprädBio study of the DKTK-ROG that recently completed recruitment, before potential application in an interventional trial.

The Expression and Prognostic Value of Cancer Stem Cell Markers, NRF2, and Its Target Genes in TAE/TACE-Treated Hepatocellular Carcinoma.

Background and Objectives: Activation of NRF2, a key transcription factor of cytoprotectant against oxidative stress, and its target genes are associated with aggressive tumor progression, metastasis and poor survival. In addition, NRF2 signaling mediates cancer stem cell (CSC)-like properties in hepatocellular carcinoma (HCC) cells. Moreover, CSCs have been associated with HCC onset and unfavorable prognosis. Transcatheter arterial embolization (TAE) and/or transcatheter arterial chemoembolization (TACE), which attempt to restrict blood supply to diminish tumor growth, can create a hypoxic environment. However, its effect on NRF2 signaling and CSC marker CD133 in the context of prognosis of HCCs have not been investigated. Therefore, we studied the possible role of the expressions of NRF2, its target genes and CSC markers CD133 and EpCAM on the survival of HCC patients after TAE/TACE. Materials and Methods: RT-qPCR was performed with 120 tumor (T) and adjacent tumor (N) tissue pairs. Expression of a single marker or combination was assessed for associations with survival of HCC patients after TAE/TACE. Results: The result of multivariate Cox regression showed that vascular invasion (HR, 1.821; p = 0.015), metastasis (HR, 2.033; p = 0.049) and CD133 overexpression (HR, 2.013; p = 0.006) were associated with poor survival. In a Kaplan–Meier survival analysis, patients with high expression of CD133 had shorter overall survival (OS) than those with low expression of CD133 in post-TAE/TACE HCC (p < 0.001). In contrast, neither NRF2 nor components of its signaling pathway correlated with survival. Combination marker analysis showed that co-expression of NQO1 and CD133 was associated with poor outcome. Conclusions: This study suggests that analyzing the expression status of CD133 alone and co-expression of NQO1 and CD133 may have additional value in predicting the outcome of TAE/TACE-treated HCC patients.

Knockdown of pancreatic adenocarcinoma upregulated factor (PAUF) suppresses proliferation, migration, invasion, and cancer stem cell properties in lung cancer cells

&#x0D; &#x0D; &#x0D; &#x0D; Purpose: To investigate the role of pancreatic adenocarcinoma up-regulated factor (PAUF) in lung cancer.&#x0D; Method: Proliferation of lung cancer cell lines (A549 and H1299) was determined using MTS and Edu staining assays. Wound healing and transwell assays were performed to evaluate cell migration and invasion abilities. Lung cancer stem cell (CSC) marker expressions, including CD133, CD44, ALDH1, SOX2, and Oct4, were determined by western blot assay.&#x0D; Results: Knockdown of PAUF significantly inhibited A459 and H1299 cell proliferation (p &lt; 0.01). The wound healing and transwell assay results indicated that depletion of PAUF markedly suppressed H1299 and A549 cell migration and invasion, compared with the control cells (p &lt; 0.01). Knockdown of PAUF reduced distinct CSC marker expression, suggesting inhibition of CSC phenotypes, and reduced phosphorylated focal adhesion kinase (FAK), phosphorylated Src, and phosphorylated extracellular signal-regulated kinase (ERK), but not total FAK, Src, and ERK. These results suggested that knockdown of PAUF deactivated the FAK/Src/ERK signal pathway.&#x0D; Conclusion: Knockdown of PAUF inhibits lung cancer cell proliferation, migration, invasion, and CSC properties via deactivation of FAK/Src/ERK signal pathway. These results may provide a novel strategy for the development of lung cancer therapeutics.&#x0D; &#x0D; &#x0D; &#x0D;

Breast Cancer Classification Based on Tumor Budding and Stem Cell-Related Signatures Facilitate Prognosis Evaluation.

BackgroundTumor budding (TB) is emerging as a prognostic factor in multiple cancers. Likewise, the stemness of cancer cells also plays a vital role in cancer progression. However, nearly no research has focused on the interaction of TB and tumor stemness in cancer.MethodsTissue microarrays including 229 cases of invasive breast cancer (BC) were established and subjected to pan-cytokeratin immunohistochemical staining to evaluate molecular expression. Univariate and multivariate analyses were applied to identify prognostic factors of BC, and the Chi-square test was used for comparison of categorical variables.ResultsHigh-grade TB was significantly associated with T stage, lymph node metastasis, tumor node metastasis (TNM) stage, epithelial-mesenchymal transition, and poor disease-free survival (DFS) of BC patients. We also found that the prognostic value of TB varied widely among different subtypes and subgroups. Cox regression analysis then showed that TB grade was an independent prognostic factor. Moreover, cancer stem cell (CSC) markers CD44 and ALDH1A1 were significantly higher in high-grade TB tumors. Consequently, patients were classified into high CSC score subgroup and low CSC score subgroups. Further research found that CSC scores correlated with clinicopathological features and DFS of BC patients. Based on TB grade and CSC scores, we classified BC patients into TBlow-CSCslow (type I), TBlow-CSCshigh (type II), TBhigh-CSCslow (type III), and TBhigh-CSCshigh (type IV) subgroups. Survival analysis showed that patients in the type I subgroup had the best DFS, whereas those in the type IV subgroup had the worst DFS. Finally, a TB-CSC-based nomogram for use in BC was established. The nomogram was well calibrated to predict the probability of 5-year DFS, and the C-index was 0.837. Finally, the area under the curve value for the nomogram (0.892) was higher than that of the TNM staging system (0.713).ConclusionThe combination of TB grade with CSC score improves the prognostic evaluation of BC patients. A novel nomogram containing TB grade and CSC score provides doctors with a candidate tool to guide the individualized treatment of cancer patients.

Functional assessment of miR‑1291 in colon cancer cells.

miR-1291 exerts an anti-tumor effect in a subset of human carcinomas, including pancreatic cancer. However, its role in colorectal cancer (CRC) is largely unknown. In the present study, the expression and effect of miR-1291 in CRC cells was investigated. It was identified that miR-1291 significantly suppressed the proliferation, invasion, cell mobility and colony formation of CRC cells. Additionally, miR-1291 induced cell apoptosis. A luciferase reporter assay revealed that miR-1291 directly bound the 3′-untranslated region sequence of doublecortin-like kinase 1 (DCLK1). miR-1291 also suppressed DCLK1 mRNA and protein expression in HCT116 cells that expressed DCLK1. Furthermore, miR-1291 suppressed cancer stem cell markers BMI1 and CD133, and inhibited sphere formation. The inhibitory effects on sphere formation, invasion and mobility in HCT116 cells were also explored and verified using DCLK1 siRNAs. Furthermore, miR-1291 induced CDK inhibitors p21WAF1/CIP1 and p27KIP1 in three CRC cell lines, and the overexpression of DCLK1 in HCT116 cells led to a decrease of p21WAF1/CIP1 and p27KIP1. Intravenous administration of miR-1291 loaded on the super carbonate apatite delivery system significantly inhibited tumor growth in the DLD-1 xenograft mouse model. Additionally, the resultant tumors exhibited significant upregulation of the p21WAF1/CIP1 and p27KIP1 protein with treatment of miR-1291. Taken together, the results indicated that miR-1291 served an anti-tumor effect by modulating multiple functions, including cancer stemness and cell cycle regulation. The current data suggested that miR-1291 may be a promising nucleic acid medicine against CRC.

Decreased expression of SVEP1 is closely related to a cancer stem cell-like phenotype and poor prognosis in hepatocellular carcinoma.

The objective of this study was to investigate the expression of SVEP1 in hepatocellular carcinoma (HCC) and to evaluate the association among SVEP1, cancer stem cell-like phenotype, and the prognosis of patients to provide new possibilities for the accurate diagnosis and stratification of HCC. Two hundred HCC and paired adjacent tissues were analyzed by immunohistochemistry and scored, and their relationships with clinicopathological parameters and survival rates were analyzed. We found that compared with adjacent tissues, the expression of SVEP1 in HCC was relatively low and was closely related to tumor size, satellite nodule formation, and histological grade (p<0.05). Statistical analysis showed that the survival rate of patients with low expression of SVEP1 decreased significantly (p<0.05). Our results showed that the expression of SVEP1 was negatively correlated with the expression of the cancer stem cell markers CD44 and CD133 (p<0.05). Moreover, multivariate Cox regression analysis showed that SVEP1 was an independent prognostic factor for the survival of HCC patients. In conclusion, our results suggest that decreased SVEP1 expression may promote HCC acquisition of a cancer stem cell-like phenotype, ultimately leading to heterogeneity and poor prognosis of HCC. This work may provide new insight into the development of HCC and suggests a potential marker for predicting the prognosis of patients.

Immunohistochemical expression of putative cancer stem cell markers aldehyde dehydrogenase 1, SOX2, CD44 and OCT4 in different grades of oral epithelial dysplasia.

The hypothesized existence of cancer stem cells (CSC) and its markers aldehyde dehydrogenase 1 (ALDH1), CD44, SOX2 and OCT4 in oral dysplastic tissues provides the potential for a more reliable assessment of malignant transformation of oral epithelial dysplasia (OED). Thus, the present study is intended to evaluate the immunohistochemical expression of four different CSC markers ALDH1, CD44, SOX2 and OCT4 in different grades of OED and to investigate the co-expression of these putative stem cell markers in OED. A total of 35 samples of varying grades of OED which included 7 mild, 11 moderate and 17 severe dysplasia samples and 10 samples of normal oral mucosa without dysplasia were used. Four sections each from all 45 samples were stained with ALDH1, CD44, SOX2 and OCT4, respectively, by immunohistochemistry. The acquired data were analyzed and evaluated using the Chi-square test and unpaired t-test and the P < 0.05 was taken significant. ALDH1 and SOX2 expression percentages showed statistically significant differences among study groups (P < 0.05). Statistical comparison of percentage expression of CD44 and OCT4 between OED and normal was nonsignificant (P > 0.05). Co-expression of all four markers was found in 15 cases of OED with none of the normal cases showing co-expression. The expression of CSC markers in OED and normal mucosa differs significantly with co-expression of all four markers located only in dysplastic tissues. Until now, no single protein marker has been able to unequivocally identify the CSCs. Thus, a panel of putative CSC markers will help in identifying the patients with high risk for malignant transformation in OED.

Cancer stem cell markers in intraoral minor salivary gland tumors.

Emerging evidence suggests the existence of a tumorigenic population of cancer cells that demonstrate stem cell-like properties. Cancer stem cells have been associated with tumor initiation and progression. The purpose of this study is to evaluate whether cancer stem cells play a functional role in the tumorigenesis of salivary gland tumors. 24 malignant, 24 benign salivary gland tumors, and seven normal salivary gland tissues were immunohistochemically stained for cancer stem cell markers ALDH1, CD44, CD24, and CD166. We scored the expressions of these proteins based on staining intensity and the ratio of positive cells. ALDH1 expression was down-regulated in malignant tumors (p = 0.034), while CD166 expression was upregulated (p = 0.002). CD44 and CD24 showed decreased expression in malignant tumors. Downregulation of ALDH expression by age also showed statistical significance (p = 0.007). ALDH1, CD166, CD44, and CD24 are potential stem cell markers for salivary gland tumors. Particularly CD166 and ALDH1 have a role in the pathogenesis and prognosis of these tumors. Loss of ALDH1 by aging may play an essential biological role in malignancy. The potential diagnostic role of ALDH1 and CD44 should be investigated.

Cancer-Associated Fibroblasts Regulate the Plasticity of Breast Cancer Stemness through the Production of Leukemia Inhibitory Factor

Simple SummaryCancer-associated fibroblasts (CAFs; as components of cancer stroma) use different signaling pathways to promote tumor progression and growth, invasion, and metastasis in diverse cancers. They have crosstalk with cancer cells during tumor progression. To investigate this crosstalk, in this study, a coculture system of CAF cells isolated from breast cancer patients with breast cancer cells was used to investigate leukemia inhibitory factor (LIF) production from CAFs. LIF is a signaling molecule that activates distinct signaling pathways through which cell cycle progression, cell death, adhesion, migration, and tumorigenesis are regulated.Leukemia inhibitory factor (LIF), as a member of the interleukin-6 cytokine family, plays a complex role in solid tumors. However, the effect of LIF as a tumor microenvironment factor on plasticity control in breast cancer remains largely unknown. In this study, an in vitro investigation is conducted to determine the crosstalk between breast cancer cells and fibroblasts. Based on the results, cancer-associated fibroblasts are producers of LIF in the cocultivation system with breast cancer cells. Treatment with the CAF-CM and human LIF protein significantly promoted stemness through the dedifferentiation process and regaining of stem-cell-like properties. In addition, the results indicate that activation of LIFR signaling in breast cancer cells in the existence of CAF-secreted LIF can induce Nanog and Oct4 expression and increase breast cancer stem cell markers CD24−/CD44+. In contrast, suppression of the LIF receptor by human LIF receptor inhibition antibody decreased the cancer stem cell markers. We found that LIF was frequently overexpressed by CAFs and that LIF expression is necessary for dedifferentiation of breast cancer cell phenotype and regaining of cancer stem cell properties. Our results suggest that targeting LIF/LIFR signaling might be a potent therapeutic strategy for breast cancer and the prevention of tumor recurrence.

MEK1/2 is a bottleneck that induces cancer stem cells to activate the PI3K/AKT pathway

Cancer stem cells (CSCs) are responsible for cancer initiation, drug resistance, and aggressive tumor phenotypes. Our lab has established a novel method to induce CSCs from induced pluripotent stem (iPS) cells in a microenvironment mimicking chronic inflammation. The converted cells acquired CSC characteristics and developed malignant tumors. Recently, we demonstrated that nonmutagenic chemical inhibitors accelerated the conversion of mouse iPS (miPS) cells into CSCs. Here, we investigated the effects of AZD-6244, a MEK1/2-specific inhibitor, on the conversion of iPS cells into CSCs. The miPS cells were cultured for one week in the presence of the conditioned medium (CM) of Lewis lung carcinoma (LLC) cells and AZD-6244, PD0325901, a pan-MEK inhibitor, or GDC-0879, a B-Raf inhibitor. As a result, AZD-6244 enhanced the conversion of iPS cells into CSCs and upregulated AKT phosphorylation as same as GDC-0879 and PD0325901. The converted cells maintained their self-renewal ability and stemness gene expression. The expression of the CSC markers CD24, CD44 and CD133 was higher in the cells cultured with MAPK inhibitors than in those cultured without MAPK inhibitors. Moreover, converted cells gained migration and invasion abilities assessed by in vitro assays. Therefore, the inhibition of MEK1/2 was found to be critical for the conversion of normal stem cells into CSCs in the tumor-inducing microenvironment.

Cell Populations Expressing Stemness-Associated Markers in Lung Adenocarcinoma.

The stemness-associated markers OCT4, NANOG, SOX2, KLF4 and c-MYC are expressed in numerous cancer types suggesting the presence of cancer stem cells (CSCs). Immunohistochemical (IHC) staining performed on 12 lung adenocarcinoma (LA) tissue samples showed protein expression of OCT4, NANOG, SOX2, KLF4 and c-MYC, and the CSC marker CD44. In situ hybridization (ISH) performed on six of the LA tissue samples showed mRNA expression of OCT4, NANOG, SOX2, KLF4 and c-MYC. Immunofluorescence staining performed on three of the tissue samples showed co-expression of OCT4 and c-MYC with NANOG, SOX2 and KLF4 by tumor gland cells, and expression of OCT4 and c-MYC exclusively by cells within the stroma. RT-qPCR performed on five LA-derived primary cell lines showed mRNA expression of all the markers except SOX2. Western blotting performed on four LA-derived primary cell lines demonstrated protein expression of all the markers except SOX2 and NANOG. Initial tumorsphere assays performed on four LA-derived primary cell lines demonstrated 0–80% of tumorspheres surpassing the 50 µm threshold. The expression of the stemness-associated markers OCT4, SOX2, NANOG, KFL4 and c-MYC by LA at the mRNA and protein level, and the unique expression patterns suggest a putative presence of CSC subpopulations within LA, which may be a novel therapeutic target for this cancer. Further functional studies are required to investigate the possession of stemness traits.

Anticancer Effect of Benzimidazole Derivatives, Especially Mebendazole, on Triple-Negative Breast Cancer (TNBC) and Radiotherapy-Resistant TNBC In Vivo and In Vitro.

In this study, we aimed to evaluate the anticancer effect of benzimidazole derivatives on triple-negative breast cancer (TNBC) and investigate its underlying mechanism of action. Several types of cancer and normal breast cells including MDA-MB-231, radiotherapy-resistant (RT-R) MDA-MB-231, and allograft mice were treated with six benzimidazole derivatives including mebendazole (MBZ). Cells were analyzed for viability, colony formation, scratch wound healing, Matrigel invasion, cell cycle, tubulin polymerization, and protein expression by using Western blotting. In mice, liver and kidney toxicity, changes in body weight and tumor volume, and incidence of lung metastasis were analyzed. Our study showed that MBZ significantly induced DNA damage, cell cycle arrest, and downregulation of cancer stem cell markers CD44 and OCT3/4, and cancer progression-related ESM-1 protein expression in TNBC and RT-R-TNBC cells. In conclusion, MBZ has the potential to be an effective anticancer agent that can overcome treatment resistance in TNBC.

Expression of cancer stem cell markers in tall cell variant papillary thyroid cancer identifies a molecular profile predictive of recurrence in classic papillary thyroid cancer

BackgroundTall cell variant of papillary thyroid carcinoma is an aggressive subtype of papillary thyroid carcinoma. We examined expression of cancer stem cell markers in tall cell variant compared with other well-differentiated thyroid cancers. MethodsExpression of cancer stem cell markers was examined in 572 thyroid tumors from The Cancer Genome Atlas Thyroid Cancer database and tall cell variant and papillary thyroid carcinoma tumors by immunohistochemistry. ResultsExpression of the PROM1 gene, encoding the cancer stem cell marker CD133, was elevated in tall cell variant compared to classic papillary thyroid carcinoma in a large cohort of unmatched samples from The Cancer Genome Atlas Thyroid Cancer database (P < .001). By immunohistochemistry in age and stage matched samples, CD133 protein was confirmed to be significantly increased in tall cell variant versus classic papillary thyroid carcinoma (P = .006). Analyzing all thyroid cancers, high PROM1 expression was associated with worse disease-specific survival. Optimal cutoffs were determined to define a tall cell variant-like cancer stem cell signature characterized by high PROM1, high ALDH1A3, and low CD24 expression. Classic papillary thyroid carcinoma with a tall cell variant-like gene signature had worse recurrence disease-free survival compared to classic papillary thyroid carcinoma with a non-tall cell variant signature (P = .02). ConclusionTall cell variant of papillary thyroid carcinoma has increased expression of cancer stem cell markers compared to classic papillary thyroid carcinoma. The tall cell variant-like cancer stem cell gene signature identified a molecular subtype of classic papillary thyroid carcinoma that has a worse recurrence-free survival.