Cancer Stem Cell Markers CD44 Research Articles

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.

Fraction B From Catfish Epidermal Secretions Kills Pancreatic Cancer Cells, Inhibits CD44 Expression and Stemness, and Alters Cancer Cell Metabolism.

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer related death in western countries. The successful treatment of PDAC remains limited. We investigated the effect of Fraction B, which is a fraction purified from catfish (Arius bilineatus, Val.) skin secretions containing proteins and lipids, on PDAC biology both in-vivo and in-vitro. We report here that Fraction B potently suppressed the proliferation of both human and mouse pancreatic cancer cells in vitro and significantly reduced the growth of their relevant xenograft (Panc02) and orthotopic tumors (human Panc-1 cells) (p < 0.05). The Reverse Phase Protein Array (RPPA) data obtained from the tumor tissues derived from orthotopic tumor bearing mice treated with Fraction B showed that Fraction B altered the cancer stem cells related pathways and regulated glucose and glutamine metabolism. The down-regulation of the cancer stem cell marker CD44 expression was further confirmed in Panc-1 cells. CBC and blood chemistry analyses showed no systemic toxicity in Fraction B treated Panc-1 tumor bearing mice compared to that of control group. Our data support that Fraction B is a potential candidate for PDAC treatment.

Discrimination of Cancer Stem Cell Markers ALDH1A1, BCL11B, BMI-1, and CD44 in Different Tissues of HNSCC Patients.

Cancer stem cells (CSCs) are accountable for the progress of head and neck squamous cell carcinoma (HNSCC). This exploratory study evaluated the expression of molecular CSC markers in different tissues of HNSCC patients. Tissue specimens of primary tumor, lymph node metastases and macroscopically healthy mucosa of 12 consecutive HNSCC patients, that were treated with surgery and adjuvant radio(chemo)therapy upon indication, were collected. Samples were assessed for the expression of p16 as a surrogate for HPV-related disease and different molecular stem cell markers (ALDH1A1, BCL11B, BMI-1, and CD44). In the cohort, seven patients had HPV-related HNSCC; six thereof were oropharyngeal squamous cell carcinoma. While expression of BMI-1 and BCL11B was significantly lower in healthy mucosa than both tumor and lymph node metastasis, there were no differences between tumor and lymph node metastasis. In the HPV-positive sub-cohort, these differences remained significant for BMI-1. However, no significant differences in these three tissues were found for ALDH1A1 and CD44. In conclusion, this exploratory study shows that CSC markers BMI-1 and BCL11B discriminate between healthy and cancerous tissue, whereas ALDH1A1 and CD44 were expressed to a comparable extent in healthy mucosa and cancerous tissues.

High Migration and Invasion Ability of PGCCs and Their Daughter Cells Associated With the Nuclear Localization of S100A10 Modified by SUMOylation

Our previous studies have confirmed that cobalt chloride (CoCl2) or chemoradiotherapy could induce the formation of polyploid tumor giant cells (PGCCs). Polyploid giant cancer cells are a special subpopulation of cancer cells that contribute to solid tumor heterogeneity. The size of PGCC was at least three times larger than regular diploid cancer cells. PGCCs have the properties of cancer stem cells (CSCs) and can express CSC markers CD44 and CD133. Daughter cells derived from PGCCs have strong proliferation, infiltration and migration abilities. However, the detailed molecular mechanism of daughter cells expressing mesenchymal phenotype and displaying strong abilities of proliferation and migration is unclear. As a plasminogen receptor, S100A10 which is closely associated with the invasion and metastasis of malignant tumors, was highly expressed in PGCCs with their daughter cells. In this study, CoCl2 was used to induce the formation of PGCCs in LoVo and HCT116 CRC cells. Cell functional experiments, co-immunoprecipitation, MG132 and ginkgolic acid treatment, western blot, and ChIP-Seq were used to identify the mechanism of S100A10 nuclear location. The proliferation and migration abilities of PGCCs and their daughter cells decreased significantly after S100A10 knockdown. In the control cells, S100A10 was mainly ubiquitinated, while in PGCCs and daughter cells, S100A10 was mainly SUMOylated, which was associated with S100A10 nuclear location. After SUMO1 was inhibited, the nuclear S100A10 in PGCCs and daughter cells decreased, and their proliferation and migration abilities significantly decreased. ChIP-Seq combined with real-time fluorescent quantitative PCR showed that S100A10 regulated the expression of neutrophil defensin 3 (DEFA3), receptor-type tyrosine-protein phosphatase N2 (PTPRN2), and rho guanine nucleotide exchange factor 18 (ARHGEF18), which were associated with actin dynamics and cytoskeleton remodeling. The expression of S100A10 in the nuclei and cytoplasm of rectal cancer after neoadjuvant chemoradiation (nCRT) and liver metastases increased compared with that in rectal cancer without nCRT. Taken together, the expression and nuclear localization of S100A10 modified by SUMOylation were associated with the high proliferation and migration of PGCCs and their daughter cells, and the differentiation, metastases, and relapse of CRCs by regulating the expression of ARHGEF18, PTPRN2, and DEFA3.

Abstract 3083: Role of S100A10 in the metastatic colonization of breast cancer stem cells

Abstract Breast cancer is now the most frequently diagnosed cancer and the leading global cause of cancer death in women. Despite advances in the diagnosis and treatment of human breast cancer, advanced stage, metastatic breast cancers are difficult to cure. Among the common target organs for breast cancer metastasis, post recurrence survival is worst when multiple metastasis was observed in the liver. Cancer stem cells (CSCs) are a sub-population of the cells that retain high tumorigenic capacity and, at the same time, are able to sustain the formation of tumors that recreate the cellular diversity of the parent lesions from which they have been originally isolated. We and others have shown that in epithelial malignancies such as breast and colorectal cancers, self-renewal ability of cancer cells with CSC properties is epigenetically regulated by their expression of microRNAs, such as with miR-200c, miR-142 and miR-221. Because of their highly tumorigenic properties, CSCs with are associated with metastatic progression, especially at the initial steps of metastases. We have previously established the breast cancer patient-derived tumor xenograft (PDX) mouse model in which CSC marker CD44+ cancer cells formed spontaneous microscopic metastases in the liver. Comparison of gene expression profiles between the CD44+ human breast cancer cells metastasized to the liver (‘metastasized CSCs') and those in the primary site (‘primary CSCs') revealed that S100A10 was upregulated in metastasized CSCs than in primary CSCs. Knockdown of S100A10 in breast cancer cells reduced the matrix metalloproteinase activity and suppressed their invasion abilities in transwell cell invasion assays in which upper surface of transwell inserts were precoated with Matrigel. Knockdown of S100A10 suppressed, and overexpression of S100A10 enhanced the 3D organoid formation capacities of breast cancer PDX cells in vitro. Finally, constitutive knockdown of S100A10 significantly reduced their metastatic ability to the liver in vivo. Upregulation of S100 family protein expression is observed in many human cancers, including breast, lung, bladder and gastric cancers. These findings suggest that S100A10 functions as a metastasis promoter of breast CSCs by conferring both invasion ability and CSC properties in breast cancers. Citation Format: Yohei Shimono, Hisano Yanagi, Takashi Watanabe, Tatsunori Nishimura, Takanori Hayashi, Seiji Okada, Motoshi Suzuki, Kenji Kawada, Hironobu Minami, Noriko Gotoh. Role of S100A10 in the metastatic colonization of breast cancer stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 3083.

The Intestinal Stem Cell Marker SMOC2 Is an Independent Prognostic Marker Associated With Better Survival in Gastric Cancer.

SPARC-related modular calcium-binding protein 2 (SMOC2), a secreted matricellular protein, is reported to be involved in cancer progression such as cell cycle, angiogenesis, and invasion. In this study, we aimed to investigate the expression of SMOC2 in various gastric lesions and assessed its prognostic value in a large cohort of gastric cancer (GC) patients. SMOC2 mRNA levels were measured by quantitative real-time PCR using 26 matched fresh-frozen GC samples. SMOC2 protein expression was determined by immunohistochemistry on tissue microarrays including 734 GC specimens and its correlations with clinicopathological features and survival were evaluated. The transcription level of SMOC2 was higher in GC samples compared to normal mucosa (p=0.006). Its expression levels were associated with the intestinal stem cell (ISC) marker, LGR5, but there were no correlations with EPHB2 and OLFM4 or the candidate cancer stem cell markers CD133 and CD44. SMOC2 expression was significantly increased in the intestinal metaplasia and was further increased in gastric adenomas and early gastric cancers (EGC). In total, 34% of GCs were positive for SMOC2, and SMOC2 positivity was higher in old (p=0.001) and male (p<0.001) patients, and in well-differentiated GC (p<0.001). SMOC2 expression had a negative association with perineural invasion (p<0.001) and tumor stage (p<0.001). In survival analysis, SMOC2-positive GC patients had much better clinical outcomes in overall survival rates (p<0.001) compared to SMOC2-negative GC patients. The prognostic impact of SMOC2 remained significant both in intestinal (p<0.001) and diffuse-type GC (p<0.001). Remarkably, a multivariate analysis demonstrated SMOC2 as an independent prognostic marker [hazard ratio (HR)=0.732, p=0.045] along with venous invasion (p=0.012), tumor stage (p<0.001) and CDX2 (p=0.028). Our results suggest that SMOC2 can be a prognostic marker for better clinical outcomes in GC.

Abstract 3116: Designing a model system for the study of CD44-Ezrin interactions in breast cancer progression and drug resistance

Abstract Triple-negative breast cancer (TNBC) has the highest risk of relapse and is thought to be the most aggressive subtype of BC. This subtype is known to express high levels of the cancer stem cell (CSC) marker CD44. The tumor-initiating properties of CSC's, as well as their resistance to chemotherapy, contribute to the difficulty in successfully treating TNBCs.CD44 is a transmembrane glycoprotein that mediates communication between cells and the extracellular matrix. In doing so, it acts as a central node in several cancer-related signaling pathways through interactions with binding partners such as Ezrin to promote tumor growth, invasion and survival. Furthermore, expression of CD44 is associated clinically with positive lymph node status, recurrence and poor overall survival in BC. We aimed to validate CD44's role in these cancer promoting properties and develop a genetically tractable and engraftable TNBC cell model to study CD44 in the context of interactions with the Ezrin adaptor protein. We first hypothesize that disrupting CD44 expression will attenuate the metastatic and drug resistant potential of TNBC cells. To address this, we utilized CRISPR-Cas9 gene editing to knockout (KO) CD44 expression in the MDA-MB-231 human TNBC cell line and then subjected CD44 KO cells, KO cells rescued with wild type CD44, or the parental MDA-MB-231 cells to a variety of in vitro assays to assess proliferative, migratory and drug resistant potential, as well as mouse lung metastatic seeding in vivo. We show that the transmembrane glycoprotein CD44 plays an important role in cancer cell proliferation, migration, and chemotherapeutic resistance in vitro as well as having an essential role in metastatic seeding in vivo in the MDA-MB-231 cell model of TNBC. Our results validate the utility of this CRISPR-Cas9 KO and rescue TNBC cell model for the study of CD44 involvement in drug resistance and metastasis. More importantly we have set the stage for further investigating CD44's role in the context of interactions with the Ezrin adaptor protein. Citation Format: Rayanna Jane Birtch, Peter Greer, Yan Gao, Victoria Hoskin. Designing a model system for the study of CD44-Ezrin interactions in breast cancer progression and drug resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 3116.

Honokiol Affects Stem Cell Viability by Suppressing Oncogenic YAP1 Function to Inhibit Colon Tumorigenesis.

Honokiol (HNK) is a biphenolic compound that has been used in traditional medicine for treating various ailments, including cancers. In this study, we determined the effect of HNK on colon cancer cells in culture and in a colitis-associated cancer model. HNK treatment inhibited proliferation and colony formation while inducing apoptosis. In addition, HNK suppressed colonosphere formation. Molecular docking suggests that HNK interacts with reserve stem cell marker protein DCLK1, with a binding energy of −7.0 Kcal/mol. In vitro kinase assays demonstrated that HNK suppressed the DCLK1 kinase activity. HNK also suppressed the expression of additional cancer stem cell marker proteins LGR5 and CD44. The Hippo signaling pathway is active in intestinal stem cells. In the canonical pathway, YAP1 is phosphorylated at Ser127 by upstream Mst1/2 and Lats1/2. This results in the sequestration of YAP1 in the cytoplasm, thereby not allowing YAP1 to translocate to the nucleus and interact with TEAD1-4 transcription factors to induce gene expression. However, HNK suppressed Ser127 phosphorylation in YAP1, but the protein remains sequestered in the cytoplasm. We further determined that this occurs by YAP1 interacting with PUMA. To determine if this also occurs in vivo, we performed studies in an AOM/DSS induced colitis-associated cancer model. HNK administered by oral gavage at a dose of 5mg/kg bw for 24 weeks demonstrated a significant reduction in the expression of YAP1 and TEAD1 and in the stem marker proteins. Together, these data suggest that HNK prevents colon tumorigenesis in part by inducing PUMA-YAP1 interaction and cytoplasmic sequestration, thereby suppressing the oncogenic YAP1 activity.

Co-Expression of LGR5 and CD133 Cancer Stem Cell Predicts a Poor Prognosis in Patients With Gastric Cancer.

The LGR5 and CD133 have been identified as cancer stem cells (CSCs) marker and prognostic marker in several cancers including gastric cancer. The purpose of the present study was to determine the association between co-expression of CSCs marker LGR5 and CD133 in patients with gastric cancer and their clinicopathological outcomes; to analyze the efficacy of co-expression of both markers in evaluating the prognosis of gastric cancer. LGR5 and CD133 expression were investigated in a total of 400 patients by using immunohistochemistry. Results were analyzed in association with patient characteristics outcomes. Overall survival was performed using Kaplan-Meier Curve analysis. LGR5 and CD133 were found positive in 219/400 (54.75%) and 251/400 (62.75%) respectively in gastric cancer tissues. Co-expression of LGR5 and CD 133 were significantly associated with poor clinicopathological outcomes, including lymphatic invasion, vascular invasion, higher pathological T stage, and higher TNM staging (stage IV) (P < .05). The overall survival of patients who were positive for LGR5 and CD133 had shorter than that of LGR5 and CD133-negative gastric cancer, especially in patients who were positive for both markers. Our finding indicates that co-expression of LGR5 and CD133 could be used as a marker indicating poor prognosis, which can provide information for selected effective treatment and carried out of intensive follow-up in gastric cancer patients.

Isolation and Characterization of Chemo-Resistant Stem Cells from a Mouse Model of Hereditary Non-Polyposis Colon Cancer.

RationaleLoss of function mutations in DNA mismatch repair genes is the primary genetic defects in high-risk hereditary non-polyposis colon cancer (HNPCC). Cytotoxic chemotherapy and anti-inflammatory drugs are potential treatment options. These treatment options lead to systemic toxicity, acquired tumor resistance and the emergence of drug-resistant stem cells. A colonic epithelial cell culture model expressing the relevant genetic defects in chemo-resistant stem cells provides a relevant experimental system for HNPCC.ObjectiveTo develop a colonic epithelial cell culture system from a mouse model for HNPCC and to isolate and characterize drug-resistant stem cells.Experimental Models and BiomarkersThe Mlh1 [-/-]/Apc [-/-] Mlh1/1638N COL-Cl1 cells is a mouse model for HNPCC, and the 5-fluoro-uracil resistant (5-FU-R) phenotype represents a model for the drug-resistant stem cells. Tumor spheroid formation, and the expression of CD44, CD133 and c-Myc represent stem cell markers.ResultsThe HNPCC model exhibits aneuploidy, hyper-proliferation, accelerated cell cycle progression and downregulated cellular apoptosis. Long-term exposure to 5-FU selects for the drug-resistant phenotype. These resistant cells exhibit increased formation of tumor spheroids and upregulated expression of cancer stem cell markers CD44, CD133 and c-Myc.ConclusionIn the present study, a stem cell model for HNPCC was validated and offered a novel experimental approach to test stem cell-targeted alternatives to drug-resistant therapy.

Cancer Stem Cell Marker CD44 Plays Multiple Key Roles in Human Cancers: Immune Suppression/Evasion, Drug Resistance, Epithelial-Mesenchymal Transition, and Metastasis.

One of the most frequently utilized cancer stem cell markers in human cancers, including colorectal cancer and breast cancer, is CD44. A glycoprotein, CD44, traverses the cell membrane and binds to many ligands, including hyaluronan, resulting in activation of signaling cascades. There are conflicting data, however, on expression of CD44 in relationship to subtypes of cancers. Moreover, the associations of CD44 expression with drug resistance, immune infiltration, epithelial-mesenchymal transition (EMT), metastasis, and clinical prognosis in several cancer types are not clear and call for further studies. We report here an original study on CD44 expression in several human cancers and its relationship with tumorigenesis. We harnessed data from the publicly available databases, including The Cancer Genome Atlas, Gene Expression Profiling Interactive Analysis, Oncomine, Genomics of Drug Sensitivity in Cancer, and the Tumor Immune Estimation Resource. Our analysis reveals that CD44 expression varies across cancer types and is significantly associated with cancer patients' survival, in gastric and pancreatic cancers (p < 0.05). In addition, CD44 expression is closely linked with immune infiltration and immune suppressive features in pancreatic, colon adenocarcinoma, and stomach cancer. High CD44 expression was significantly correlated with the expression of drug resistance, EMT, and metastasis associated genes. Tumors expressing high CD44 have higher mutation burden and afflict older patients compared to tumors expressing low CD44. Cell lines expressing high CD44 are more resistant to anticancer drugs compared to those expressing low CD44. Protein-protein interaction investigations and functional enrichment analysis showed that CD44 interacts with gene products related to cell-substrate adhesion, migration, platelet activation, and cellular response to stress. Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that these genes play key roles in biological adhesion, cell component organization, locomotion, G-α-signaling, and the response to stimulus. In summary, these findings lend evidence for the multiple key roles played by CD44 in tumorigenesis and suggest that CD44 is considered further in future studies of cancer pathogenesis and the search for novel molecular targets and personalized medicine biomarkers in clinical oncology.

Celastrol and Triptolide Suppress Stemness in Triple Negative Breast Cancer: Notch as a Therapeutic Target for Stem Cells.

Triple negative breast cancer (TNBC) is observed in ~15% of breast cancers and results in poor survival and increased distant metastases. Within the tumor are present a small portion of cancer stem cells that drive tumorigenesis and metastasis. In this study, we aimed to elucidate whether the two natural compounds, celastrol and triptolide, inhibit stemness in TNBC. MDA-MB-231, BT20, and a patient-derived primary cells (PD-TNBC) were used in the study. Mammosphere assay was performed to assess the stemness. Both celastrol and triptolide treatment suppressed mammosphere formation. Furthermore, the compound suppressed expression of cancer stem cell marker proteins DCLK1, ALDH1, and CD133. Notch signaling plays a critical role in stem cells renewal. Both celastrol or triptolide reduced Notch -1 activation and expression of its downstream target proteins HES-1 and HEY-1. However, when NICD 1 was ectopically overexpressed in the cells, it partially rescued proliferation and mammosphere formation of the cells, supporting the role of notch signaling. Together, these data demonstrate that targeting stem cells and the notch signaling pathway may be an effective strategy for curtailing TNBC progression.

Laminin-411 and -511 Modulate the Proliferation, Adhesion, and Morphology of Gastric Cancer Cells.

Laminins (Ln), a type of extracellular matrix glycoprotein, are key regulators of cellular behavior. Recent work revealed that in various tumor cell lines, laminin isoforms influence specific responses, such as cell anchorage, survival, proliferation, migration, organization, and specialization. The contribution of laminin isoforms to the function of gastric cancer cells, however, remain unclear. Here, we revealed that in gastric cancer, laminin isoforms Ln411, Ln421, Ln511, and Ln521 promote cellular proliferation; Ln511 and Ln521 increase cell cytoplasmic volume; Ln511 hampers invadopodia formation in some cells, Ln511 enables prompt adhesion of cells to plates, and Ln411 and Ln511 do not alter the gastric cancer stem cell markers CD44 and Lgr5. These results indicate that Ln411 and Ln511 dynamically modulate the proliferation, adhesion, and morphology of gastric cancer cells in different ways that are independent of stem cell properties. In particular, Ln511 showed a high affinity for gastric cancer cells. Our observations broaden the possible options for controlling cancer cell progression and metastasis by modulating laminin-integrin interactions.

ATF3 inhibits the growth and stem cells-like features of SW620 colorectal cancer cells in vitro

Background and objective: Activating transcription factor 3 (ATF3) plays a crucial role in regulating tumor development depending on the cellular context or cancer cell type. However, the effect of ATF3 on stem cells-like features in colorectal cancer (CRC) has yet to be elaborated. Methods: In this study, we overexpressed ATF3 in SW620 CRC cells to investigate its effects on stem cells-like features. Results: Our results indicated that overexpressing ATF3 inhibited the proliferation, invasion, migration, and sphere formation capacity of SW620 CRC cells. ATF3 overexpression also decreased the size of tumorspheres and reduced expression of the cancer stem cell markers CD44 and CD133 in SW620 cells. Conclusion: In summary, our study revealed that ATF3 suppresses CRC growth and stem cells-like features. ATF3 is considered a potential target in CRC therapy.

The expression of CD44, CD90 and CD133 in response to cisplatin in hepatocellular cancer cells

Introduction. Cancer is a leading cause of mortality. Hepatocellular cancer is one of the malignancies associated with poor outcome and resistance to pharmacotherapy. Cancer stem cells (CSCs) contribute to resistance to therapy and hence lead to the treatment failure of tumors. Aim. This study aims to explore the expression of CSCs in response to cisplatin treatment in HepG2 hepatocellular cancer cell line. Material and methods. Cell proliferation test, CCK-8, was used to evaluate the cell proliferation following cisplatin treatment for 72 hours. The expressions of CSC markers CD44, CD90, and CD133 were assessed by flow cytometric analysis. Results. The results showed a dose-dependent decrease in cell proliferation and increased expression of CSC markers CD44 and CD90 in response to cisplatin. Conclusion. Understanding the roles of CSC markers may point to new targets and therapeutic strategies to predict and overcome cisplatin resistance.