Prognostic impact of the expression of ALDH1 and SOX2 in urothelial cancer of the upper urinary tract

Silencing the Mitochondrial Gatekeeper VDAC1 as a Potential Treatment for Bladder Cancer

The strategy for treating bladder cancer (BC) depends on whether there is muscle invasion or not, with the latter mostly treated with intravesical therapy, such as with bacillus Calmette-Guérin (BCG). However, BCG treatment is unsuccessful in 70% of patients, who are then subjected to radical cystectomy. Although immune-checkpoint inhibitors have been approved as a second-line therapy for a subset of BC patients, these have failed to meet primary endpoints in clinical trials. Thus, it is crucial to find a new treatment. The mitochondrial gatekeeper protein, the voltage-dependent anion channel 1 (VDAC1), mediates metabolic crosstalk between the mitochondria and cytosol and is involved in apoptosis. It is overexpressed in many cancer types, as shown here for BC, pointing to its significance in high-energy-demanding cancer cells. The BC cell lines UM-UC3 and HTB-5 express high VDAC1 levels compared to other cancer cell lines. VDAC1 silencing in these cells using siRNA that recognizes both human and mouse VDAC1 (si-m/hVDAC1-B) reduces cell viability, mitochondria membrane potential, and cellular ATP levels. Here, we used two BC mouse models: subcutaneous UM-UC3 cells and chemically induced BC using the carcinogen N-Butyl-N-(4-hydroxybutyl) nitrosamine (BBN). Subcutaneous UM-UC3-derived tumors treated with si-m/hVDAC1 showed inhibited tumor growth and reprogrammed metabolism, as reflected in the reduced expression of metabolism-related proteins, including Glut1, hexokinase, citrate synthase, complex-IV, and ATP synthase, suggesting reduced metabolic activity. Furthermore, si-m/hVDAC1-B reduced the expression levels of cancer-stem-cell-related proteins (cytokeratin-14, ALDH1a), modifying the tumor microenvironment, including decreased angiogenesis, extracellular matrix, tumor-associated macrophages, and inhibited epithelial-mesenchymal transition. The BBN-induced BC mouse model showed a clear carcinoma, with damaged bladder morphology and muscle-invasive tumors. Treatment with si-m/hVDAC1-B encapsulated in PLGA-PEI nanoparticles that were administered intravesically directly to the bladder showed a decreased tumor area and less bladder morphology destruction and muscle invasion. Overall, the obtained results point to the potential of si-m/hVDAC1-B as a possible therapeutic tool for treating bladder cancer.

SOX2 Promotes Invasion in Human Bladder Cancers through MMP2 Upregulation and FOXO1 Downregulation

SOX2, a member of the SRY-related HMG-box (SOX) family, is abnormally expressed in many tumors and associated with cancer stem cell-like properties. Previous reports have shown that SOX2 is a biomarker for cancer stem cells in human bladder cancer (BC), and our most recent study has indicated that the inhibition of SOX2 by anticancer compound ChlA-F attenuates human BC cell invasion. We now investigated the mechanisms through which SOX2 promotes the invasive ability of BC cells. Our studies revealed that SOX2 promoted SKP2 transcription and increased SKP2-accelerated Sp1 protein degradation. As Sp1 is a transcriptionally regulated gene, HUR transcription was thereby attenuated, and, in the absence of HUR, FOXO1 mRNA was degraded fast, which promoted BC cell invasion. In addition, SOX2 promoted BC invasion through the upregulation of nucleolin transcription, which resulted in increased MMP2 mRNA stability and expression. Collectively, our findings show that SOX2 promotes BC invasion through both SKP2-Sp1-HUR-FOXO1 and nucleolin-MMP2 dual axes.

Wnt/β-Catenin Signaling Contributes to Paclitaxel Resistance in Bladder Cancer Cells with Cancer Stem Cell-Like Properties

The Wnt/β-catenin pathway plays an important role in tumor progression and chemotherapy resistance and seems to be essential for the maintenance of cancer stem cells (CSC) in several tumor types. However, the interplay of these factors has not been fully addressed in bladder cancer. Here, our goal was to analyze the role of the Wnt/β-catenin pathway in paclitaxel resistance and to study the therapeutic efficacy of its inhibition in bladder cancer cells, as well as to determine its influence in the maintenance of the CSC-like phenotype in bladder cancer. Our results show that paclitaxel-resistant HT1197 cells have hyperactivation of the Wnt/β-catenin pathway and increased CSC-like properties compared with paclitaxel-sensitive 5637 cells. Paclitaxel sensitivity diminishes in 5637 cells after β-catenin overexpression or when they are grown as tumorspheres, enriched for the CSC-like phenotype. Additionally, downregulation of β-catenin or inhibition with XAV939 sensitizes HT1197 cells to paclitaxel. Moreover, a subset of muscle-invasive bladder carcinomas shows aberrant expression of β-catenin that associates with positive expression of the CSC marker ALDH1A1. In conclusion, we demonstrate that Wnt/β-catenin signaling contributes to paclitaxel resistance in bladder cancer cells with CSC-like properties.

The Expression of Selected Wnt Pathway Members (FZD6, AXIN2 and β-Catenin) in Canine Oral Squamous Cell Carcinoma and Acanthomatous Ameloblastoma

The Wnt signaling pathway is well known to be involved in many types of human cancer; however, in veterinary medicine, the investigation of individual Wnt members' expression, and their role in or association with oral tumor pathogenesis, is still underevaluated. We aim to determine the expression pattern of Frizzled-6 (FZD6) as one of the Wnt receptors in two of the most common canine oral neoplastic lesions-canine oral squamous cell carcinoma (COSCC) and canine acanthomatous ameloblastoma (CAA). While COSCC is a malignant tumor with aggressive biological behavior and a tendency to metastasize, CAA is a benign tumor with high local invasiveness. In CAA, the expression of FZD6 was mostly located in the center of the epithelial tumorous tissue, and cells exhibiting features of squamous metaplasia were strongly positive. In well-differentiated COSCC, FZD6 was expressed in the tumorous epithelium as well as the tumorous stroma. There was a negative correlation between cytokeratin expression and FZD6 expression in COSCC, where the central parts of the epithelial tumorous tissue were often FZD6-negative. The non-differentiated COSCC with low expression of cytokeratin exhibited a diffuse FZD6 signal. The invasive front with areas of tumor budding exhibited high FZD6 expression with a loss of cytokeratin expression. Moreover, the expression of β-catenin and AXIN2 was increased in comparison to gingiva. In conclusion, our study revealed significant differences in the expression patterns and the levels of FZD6 between COSCC and CAA, indicating the differential engagement of the Wnt pathway in these tumors.

Increased expression of ALDH-1 is associated with clinical parameters of salivary glands neoplasms

The enzyme aldehyde dehydrogenase-1 (ALDH-1) is a known putative tumour stem cells (TSC) marker, and these cells are implicated in carcinogenesis and progression of human neoplasms. We aimed to evaluate ALDH-1 expression in benign and malignant salivary gland neoplasms and its clinicopathological and prognostic significance. Expression of ALDH-1 was investigated by immunohistochemistry and confirmed by Western Blot analysis in 154 salivary gland neoplasms (103 malignant and 51 benign neoplasms). The expression was identified in the parenchyma of malignant (n = 88; 85.6%) and benign (100%) neoplasms. Overall, expression in the parenchyma varied considerably and was not associated with clinical parameters in most malignant neoplasms, however, a high expression in mucoepidermoid carcinomas (MEC) was associated with advanced pathological TNM stage (p = 0.047). The presence of ALDH-1 in stromal cells of malignant neoplasms (n = 67; 65.0%) was associated with lymph node metastasis (p = 0.032), tumour recurrence (p = 0.006) and death (p = 0.013). Overall and disease-free survival in 5 and 10 years was lower in patients with diagnosis of adenoid cystic carcinoma, tumour recurrence, advanced staging, and presence of ALDH-1 in the stroma. When adjusted by multivariate analysis, advanced staging and stromal expression were independent prognostic factors affecting disease-free survival. Our findings provide evidence that cells characterized as TSC in the parenchyma and stroma are differentially present among the different types of neoplasms studied and may be related to tumourigenesis, biological behaviour and persistence capacity of malignant tumours of the salivary gland.

Functional characterization of SOX2 as an anticancer target

SOX2 is a well-characterized pluripotent factor that is essential for stem cell self-renewal, reprogramming, and homeostasis. The cellular levels of SOX2 are precisely regulated by a complicated network at the levels of transcription, post-transcription, and post-translation. In many types of human cancer, SOX2 is dysregulated due to gene amplification and protein overexpression. SOX2 overexpression is associated with poor survival of cancer patients. Mechanistically, SOX2 promotes proliferation, survival, invasion/metastasis, cancer stemness, and drug resistance. SOX2 is, therefore, an attractive anticancer target. However, little progress has been made in the efforts to discover SOX2 inhibitors, largely due to undruggable nature of SOX2 as a transcription factor. In this review, we first briefly introduced SOX2 as a transcription factor, its domain structure, normal physiological functions, and its involvement in human cancers. We next discussed its role in embryonic development and stem cell-renewal. We then mainly focused on three aspects of SOX2: (a) the regulatory mechanisms of SOX2, including how SOX2 level is regulated, and how SOX2 cross-talks with multiple signaling pathways to control growth and survival; (b) the role of SOX2 in tumorigenesis and drug resistance; and (c) current drug discovery efforts on targeting SOX2, and the future perspectives to discover specific SOX2 inhibitors for effective cancer therapy.

A SNP of miR-146a is involved in bladder cancer relapse by affecting the function of bladder cancer stem cells via the miR-146a signallings

MiR‐146a‐5p in urine samples was recently reported to be possibly used as a prognostic marker for bladder cancer (BC). Interestingly, YAP1 and COX2 were both demonstrated to function as stem cell regulators in BC. Therefore, in this study, we aimed to establish the molecular mechanism underlying the role of miR‐146a, YAP1 and COX2 in BC relapse. We also studied the possibility of using the C > G genotype of miR‐146a rs2910164 SNP as an indicator of BC relapse. A total of 170 BC patients were assigned into different groups based on their genotypes of rs2910164 SNP. Kaplan‐Meier survival curves were plotted to compare the recurrence‐free rate among these groups. Real‐time PCR, Western Blot, bioinformatic analysis, luciferase assay and IHC assay were conducted to study the role of rs2910164 SNP in the progression of BC. Accordingly, GC/CC‐genotyped patients presented a higher risk of recurrence when compared with GG‐genotyped patients, while the expression of BC regulators was influenced by the presence of rs2910164. COX2 mRNA and YAP1 mRNA were, respectively, validated as direct target genes of miR‐146a, and the expression of YAP1 and COX2 mRNA/protein was both suppressed by miR‐146a precursors. The expression of ALDH1A1 mRNA/protein was inhibited upon the down‐regulation of YAP1, while the expression of let7 and SOX2 mRNA/protein was inhibited upon the down‐regulation of COX2. In conclusion, two signalling pathways, miR‐146a/YAP1/ALDH1A1 and miR‐146a/COX2/PGE2/let7/SOX2, were modulated by miR‐146a. As an SNP regulating the expression of miR‐146a, the rs2910164 G > C SNP could be utilized as a biomarker for BC relapse.

Establishment of 2.5D organoid culture model using 3D bladder cancer organoid culture

Three-dimensional (3D) organoid culture holds great promises in cancer precision medicine. However, Matrigel and stem cell-stimulating supplements are necessary for culturing 3D organoid cells. It costs a lot of money and consumes more time and effort compared with 2D cultured cells. Therefore, the establishment of cheaper and Matrigel-free organoid culture that can maintain the characteristics of a part of 3D organoids is demanded. In the previous study, we established a dog bladder cancer (BC) 3D organoid culture system by using their urine samples. Here, we successfully isolated cells named "2.5D organoid" from multiple strains of dog BC 3D organoids using 2.5 organoid media. The cell proliferation speed of 2.5D organoids was faster than parental 3D organoid cells. The expression pattern of stem cell markers was close to 3D organoids. Injection of 2.5D organoid cells into immunodeficient mice formed tumors and showed the histopathological characteristics of urothelial carcinoma similar to the injection of dog BC 3D organoids. The 2.5D organoids had a similar sensitivity profile for anti-cancer drug treatment to their parental 3D organoids. These data suggest that our established 2.5D organoid culture method might become a reasonable and useful tool instead of 3D organoids in dog BC research and therapy.

Increased Expression Of SOX2 Predicts A Poor Prognosis And Promotes Malignant Phenotypes In Upper Tract Urothelial Carcinoma

Background

The transcription factor SRY-related HMG-box 2 (SOX2) plays important regulatory roles in diverse biological processes (cell proliferation, migration, invasion and tumorigenicity). However, the relationship between SOX2 and upper tract urothelial carcinoma (UTUC) have not been intensively investigated. This study aims to analyze the expression of SOX2 in UTUC as well as the predictive value for prognosis and the effect on tumor aggressiveness of SOX2.

Methods

Formalin-fixed, paraffin-embedded blocks containing samples from 341 patients with UTUC who underwent radical nephroureterectomy (RNU) at our institute were analyzed for SOX2 expression by immunohistochemistry (IHC). Associations between the SOX2 expression level and clinicopathological characteristics, disease-free survival (DFS) and cancer-specific survival (CSS) were analyzed. SOX2 expression in a normal urothelial cell line, urothelial carcinoma cell lines, 16 UTUC tissues and their pair-matched adjacent normal tissues was evaluated by RT-qPCR. Using RNA interference in vitro, the effects of SOX2 inhibition on cell proliferation, migration, invasion and tumorigenicity were determined.

Results

SOX2 expression was significantly upregulated in UTUC tissue samples compared with paired-adjacent nontumorous tissue samples. SOX2 expression was correlated with important clinicopathological features, including tumor stage, tumor grade, tumor architecture and the presence of glandular or sarcoma differentiation, and was an independent predictor of poor DFS and CSS. Further experiments indicated that SOX2 expression was higher in UTUC cell lines than in a normal urothelial cell line. Knocking down SOX2 expression could inhibit malignant phenotypes (cell proliferation, stemness, migration, invasion and tumorigenicity) in UTUC cells.

Conclusion

SOX2 is an independent prognostic marker of poor DFS and CSS in UTUC patients who have undergone RNU. Moreover, these data suggest that SOX2 may be a promising therapeutic target in UTUC.

High expression level of SOX2 is significantly associated with shorter survival in patients with thymic epithelial tumors

OBJECTIVES

Thymic epithelial tumors (TET) are heterogenous tumors which are composed of thymoma (TM) and thymic carcinoma (TC). We attempted to determine differences in gene expression between TM and TC, and to determine the effect of such genes on the prognosis of patients with TET.

MATERIALS AND METHODS

Gene expression profiles of SOX2, OCT-4, IGF-1, IGF-1R and IR mRNA transcripts in tumor tissues of TM and TC were determined using real-time PCR (RT-PCR). We constructed tissue microarray with 140 paraffin-embedded tumor tissues and performed immunohistochemistry (IHC) for IGF-1R-related signaling molecules, including SOX2, IGF-1, IGF-1R and pAKT.

RESULTS

SOX2 mRNA expression was notably higher (216-fold) in TCs than in TMs. However, there was no significant difference in expression of IGF-1, IGF-1R, OCT-4 or IR between the two tumor types. In IHC results, SOX2 (HR: 7.57, P = 0.001) and IGF-1 (HR: 9.43, P = 0.001) expression levels in TC were significantly higher than those in TM. There was a significant correlation in expression of SOX2 with IGF-1 (P = 0.021) and pAKT (P = 0.026). In univariate analysis, clinical TNM stage, WHO classification, serum LDH, expression of SOX2, IGF-1R, IGF-1 and pAKT, were significantly correlated with overall survival (OS). Multivariate analysis using a forward-selection procedure revealed that clinical N stage (HR: 4.08, P < 0.001), M stage (HR: 3.37, P = 0.001) and SOX2 expression (HR: 4.53, P = 0.010) were significantly associated with OS.

CONCLUSIONS

SOX2 is expressed significantly higher in TC than in TM. SOX2 expression is also closely related to IGF-1 and pAKT expression. The higher expression of SOX2 is significantly associated with shorter survival in patients with TET.

CHI3L1 results in poor outcome of ovarian cancer by promoting properties of stem-like cells

The role of chitinase-3-like protein 1 (CHI3L1) in ovarian cancer and the possible mechanisms were elucidated. CHI3L1 is a secreted glycoprotein and associated with inflammation, fibrosis, asthma, extracellular tissue remodeling and solid tumors. Our previous study showed CHI3L1 could be a potential prognostic biomarker for epithelial ovarian cancer and could protect cancer cells from apoptosis. Therefore, clinical data and quantitation of CHI3L1 of ovarian cancer patients, tumor spheroid formation, side-population assays, Aldefluor and apoptotic assays, ELISA, RT-PCR, immunoblotting and animal experiments were performed in two ovarian cancer cells lines, OVCAR3 and CA5171, and their CHI3L1-overexpressing and -knockdown transfectants. High expression of CHI3L1 was associated with poor outcome and chemoresistance in ovarian cancer patients. The mRNA expression of CHI3L1 in CA5171 ovarian cancer stem-like cells was 3-fold higher than in CA5171 parental cells. CHI3L1 promoted the properties of ovarian cancer stem-like cells including generating more and larger tumor spheroids and a higher percentage of ALDH+ in tumor cells and promoting resistance to cytotoxic drug-induced apoptosis. CHI3L1 could induce both the Akt (essential) and Erk signaling pathways, and then enhance expression of β-catenin followed by SOX2, and finally promote tumor spheroid formation and other properties of ovarian cancer stem-like cells. OVCAR3 CHI3L1-overexpressing transfectants were more tumorigenic in vivo, whereas CA5171 CHI3L1-knockdown transfectants were not tumorigenic in vivo. CHI3L1 critically enhances the properties of ovarian cancer stem-like cells. CHI3L1 or CHI3L1-regulated signaling pathways and molecules could be potential therapeutic targets in ovarian cancer.

Stem-Like Signature Predicting Disease Progression in Early Stage Bladder Cancer. The Role of E2F3 and SOX4

The rapid development of the cancer stem cells (CSC) field, together with powerful genome-wide screening techniques, have provided the basis for the development of future alternative and reliable therapies aimed at targeting tumor-initiating cell populations. Urothelial bladder cancer stem cells (BCSCs) that were identified for the first time in 2009 are heterogenous and originate from multiple cell types; including urothelial stem cells and differentiated cell types—basal, intermediate stratum and umbrella cells Some studies hypothesize that BCSCs do not necessarily arise from normal stem cells but might derive from differentiated progenies following mutational insults and acquisition of tumorigenic properties. Conversely, there is data that normal bladder tissues can generate CSCs through mutations. Prognostic risk stratification by identification of predictive markers is of major importance in the management of urothelial cell carcinoma (UCC) patients. Several stem cell markers have been linked to recurrence or progression. The CD44v8-10 to standard CD44-ratio (total ratio of all CD44 alternative splicing isoforms) in urothelial cancer has been shown to be closely associated with tumor progression and aggressiveness. ALDH1, has also been reported to be associated with BCSCs and a worse prognosis in a large number of studies. UCC include low-grade and high-grade non-muscle invasive bladder cancer (NMIBC) and high-grade muscle invasive bladder cancer (MIBC). Important genetic defects characterize the distinct pathways in each one of the stages and probably grades. As an example, amplification of chromosome 6p22 is one of the most frequent changes seen in MIBC and might act as an early event in tumor progression. Interestingly, among NMIBC there is a much higher rate of amplification in high-grade NMIBC compared to low grade NMIBC. CDKAL1, E2F3 and SOX4 are highly expressed in patients with the chromosomal 6p22 amplification aside from other six well known genes (ID4, MBOAT1, LINC00340, PRL, and HDGFL1). Based on that, SOX4, E2F3 or 6q22.3 amplifications might represent potential targets in this tumor type. Focusing more in SOX4, it seems to exert its critical regulatory functions upstream of the Snail, Zeb, and Twist family of transcriptional inducers of EMT (epithelial–mesenchymal transition), but without directly affecting their expression as seen in several cell lines of the Cancer Cell Line Encyclopedia (CCLE) project. SOX4 gene expression correlates with advanced cancer stages and poor survival rate in bladder cancer, supporting a potential role as a regulator of the bladder CSC properties. SOX4 might serve as a biomarker of the aggressive phenotype, also underlying progression from NMIBC to MIBC. The amplicon in chromosome 6 contains SOX4 and E2F3 and is frequently found amplified in bladder cancer. These genes/amplicons might be a potential target for therapy. As an existing hypothesis is that chromatin deregulation through enhancers or super-enhancers might be the underlying mechanism responsible of this deregulation, a potential way to target these transcription factors could be through epigenetic modifiers.

CD44 and ALDH1 immunoexpression as prognostic indicators of invasion and metastasis in oral squamous cell carcinoma

BACKGROUND

Tumour metastasis has been associated with cancer stem cells, a small population with stem-like cells properties, higher rate of migration and metastatic potential compared to cells from the tumour bulk. Our aim was to evaluate the immunoexpression of the putative cancer stem cell biomarkers ALDH1 and CD44 in primary tumour and corresponding metastatic lymph nodes.

METHODS

Tumour tissue specimens (n = 50) and corresponding metastatic lymph nodes (n = 25) were surgically obtained from 50 patients with oral squamous cell carcinoma and submitted to immunohistochemistry. CD44 and ALDH1 were semi-quantitatively scored according to the proportion and intensity of positive cells within the invasive front and metastatic lymph nodes as a whole. A combined score was obtained by multiplying both parameters and later dichotomized into a final score classified as low (≤2) or high (>2) immunoexpression.

RESULTS

ALDH1 immunoexpression and CD44 immunoexpression were detected in both tumour sites, although the means of ALDH1 (P = .0985) and CD44 (P = .4220) cells were higher in metastasis compared to primary tumours. ALDH1^high was positively associated (P = .0184) with angiolymphatic invasion, while CD44^high was positively associated (P = .0181) with metastasis (N+). At multivariate analysis, CD44 significantly increased the odds of lymph node metastasis, regardless of T stage (OR = 8.24; 1.64-65.64, P = .0088).

CONCLUSIONS

CD44 immunoexpression was a significant predictor of lymph node metastasis, while ALDH1^high immunostaining was associated with angiolymphatic invasion. Altogether, it suggests that immunoexpression of CD44 and ALDH1 links the cancer stem cell phenotype with oral squamous cell carcinoma invasion and metastasis.

SOX2 Is a Marker for Stem-like Tumor Cells in Bladder Cancer

It has been reported that functionally distinct cancer stem cells (CSCs) exist in human bladder cancer (BCa). Here, we found that Sox2, a transcription factor that is well characterized as a marker for stem cells, is upregulated in both mouse and human BCa. Sox2 expression is absent in normal urothelial cells, but it begins to be expressed in pre-neoplastic bladder tumors and continues to be expressed in invasive mouse BCa. Using s as a reporter of Sox2 transcriptional expression, we demonstrated that Sox2-expressing cells mark a subpopulation of tumor cells that fuel the growth of established BCa. SOX2-positive cells also expressed other previously reported BCa CSC markers, including Keratin14 (KRT14) and CD44v6. Ablation of Sox2-expressing cells within primary invasive BCa led to enhanced tumor regression, supporting the essential role of SOX2-positive cells in regulating BCa maintenance and progression. Our data show that Sox2 is a marker of bladder CSCs and indicate it as a potential clinical target for BCa therapy.

•

Sox2 expression marks bladder cancer stem cells in vivo

•

SOX2-positive cells are a subpopulation of KRT14-expressing cancer stem cells

•

SOX2-positive cells are a subpopulation of CD44v6-expressing cancer stem cells

•

Elimination of Sox2-expressing cells led to reduction of bladder cancer progression

Alterations in cancer stem-cell marker CD44 expression predict oncologic outcome in soft-tissue sarcomas

BACKGROUND

Cancer stem cells (CSCs) have been shown to resist chemotherapy and promote metastasis after cytotoxic therapies. We sought to determine if the expression of CSC markers (aldehyde dehydrogenase [ALDH], CD44, and epidermal growth factor receptor [EGFR]) predicted outcomes in soft-tissue sarcoma (STS) patients.

METHODS

We queried an institutional database of 23 STS patients and evaluated immunohistochemical expression of CSC markers ALDH, CD44, and EGFR. The Cancer Genome Atlas (TCGA) was also queried for STS clinical and genomic data. Disease-specific (DSS) and overall survival (OS) were assessed by univariate and Kaplan-Meier analysis.

RESULTS

Of the 23 institutional patients, the majority was female, had high-grade tumors and had extremity tumors. With a median follow-up of 27 months, nine patients (39%) experienced distant recurrence, and four (17%) died of disease. Mean H-scores at diagnosis (±standard error of the mean) for CD44, ALDH1, and EGFR were 169 ± 27, 77 ± 15, and 144 ± 23, respectively. On univariate analysis, there was a trend for increased CD44 score to predict both worse DSS and OS (hazard ratio = 1.01, 95% confidence interval 1-1.02, P = 0.056), whereas ALDH and EGFR scores did not. Analysis of 74 TCGA STS cases with complete clinical and genomic data revealed that CD44 copy number alterations predicted worse DSS (9.89 months versus 72.5 months, P = 0.007) and a trend for worse OS (14.03 months versus 38.6 months, P = 0.12), whereas ALDH1 and EGFR copy number alteration did not. Multivariate analysis of the combined data sets was consistent with worse DSS among patients with higher CD44 expression.

CONCLUSIONS

Institutional and national TCGA data show the association of elevated baseline CD44 expression with worse STS outcomes. Further study of CD44 as a possible novel STS biomarker appears indicated.

High ALDH1A1 expression indicates a poor prognosis in gastric neuroendocrine carcinoma

OBJECTIVE

To evaluate the expression and prognostic significance of ALDH1A1 in gastric neuroendocrine carcinoma.

MATERIALS AND METHODS

Immunohistochemical stains of ALDH1A1 were evaluated in 67 cases of gastric neuroendocrine carcinoma. The findings were correlated with clinicopathologic variables and overall survival.

RESULTS

Immunohistochemistry revealed positive cytoplasmic immunoreactivity in 35 of 67 (52.2%) tumors and strongly positive immunoreactivity in 14 of 67 (20.9%). Strongly positive ALDH1A1 expression, but not positive staining, was significantly associated with lymph node status, lymphovascular invasion, and ki-67 index (P=0.039, 0.045, and 0.045, respectively). Kaplan-Meier survival curves and log-rank tests showed significantly poorer prognoses in cases of high ALDH1A1 expression compared to cases of low ALDH1A1 expression or the negative control group (MST, 17 vs. 52 months; P=0.026). Multivariate analysis showed that high ALDH1A1 expression, lymph node metastasis, and lymphovascular invasion had significant associations with decreased overall survival (P=0.029, 0.008, and 0.005, respectively).

CONCLUSIONS

High ALDH1A1 expression may be a prognostic indicator of survival in patients with gastric neuroendocrine carcinoma.

Cancer stem cells and epithelial-mesenchymal transition in urothelial carcinoma: Possible pathways and potential therapeutic approaches

There is growing evidence of the presence of cancer stem cells in urothelial carcinoma. Cancer stem cells have the ability to self-renew and to differentiate into all cell types of the original heterogeneous tumor. A panel of diverse cancer stem cell markers might be suitable for simulation studies of urothelial cancer stem cells and for the development of optimized treatment protocols. The present review focuses on the advances in recognizing the markers of urothelial cancer stem cells and possible therapeutic targets. The commonly reported markers and pathways that were evaluated include CD44, CD133, ALDH1, SOX2 & SOX4, BMI1, EZH1, PD-L1, MAGE-A3, COX2/PGE2/STAT3, AR, and autophagy. Studies on the epithelial-mesenchymal transition-related pathways (Shh, Wnt/β-catenin, Notch, PI3K/Akt, TGF-β, miRNA) are also reviewed. Most of these markers were recognized through the expression patterns of cancer stem cell-rich side populations. Their regulative role in the development and differentiation of urothelial cancer stem cells was confirmed in vitro by functional analyses (e.g. cell migration, colony formation, sphere formation), and in vivo in xenograft experiments. Although a small number of these pathways are targeted by currently available drugs or drugs that are the currently being tested in clinical trials, a clear treatment approach has not been developed for most pathways. A greater understanding of the mechanisms that control the proliferation and differentiation of cancer stem cells is expected to lead to improvements in targeted therapy.

GRIK2 has a role in the maintenance of urothelial carcinoma stem-like cells, and its expression is associated with poorer prognosis

Cancer stem-like cells (CSCs)/cancer-initiating cells (CICs) are small sub-population of cancer cells that are endowed with higher tumor-initiating ability, self-renewal ability and differentiation ability. CSCs/CICs could be isolated as high aldehyde dehydrogenase 1 activity cells (ALDH1high) from various cancer samples. In this study, we isolated urothelial carcinoma CSCs/CICs as ALDHhigh cells and investigated the molecular aspects. ALDH1high cells showed greater sphere-forming ability and higher tumor-initiating ability in immune-deficient mice than those of ALDH1low cells, indicating that CSCs/CICs were enriched in ALDH1high cells. cDNA microarray analysis revealed that an ionotropic glutamate receptor glutamate receptor, ionotropic, kainate 2 (GRIK2) was expressed in ALDH1high cells at a higher level than that in ALDH1low cells. GRIK2 gene knockdown by siRNAs decreased the sphere-forming ability and invasion ability, whereas GRIK2 overexpression increased the sphere-forming ability, invasion ability and tumorigenicity, indicating that GRIK2 has a role in the maintenance of CSCs/CICs. Immunohistochemical staining revealed that higher levels of GRIK2 and ALDH1 expression were related to poorer prognosis in urinary tract carcinoma cases. The findings indicate that GRIK2 has a role in the maintenance of urothelial CSCs/CICs and that GRIK2 and ALDH1 can be prognosis prediction markers for urinary tract carcinomas.

Evaluation of the Role of ALDH1 as Cancer Stem Cell Marker in Colorectal Carcinoma: An Immunohistochemical Study

INTRODUCTION

Colorectal Carcinoma (CRC) is the third most commonly diagnosed cancer in males. Stem Cells (SC) may be involved in tumour growth, including colon cancer. Aldehyde Dehydrogenase 1 (ALDH1) is a detoxifying enzyme that might modulate SC proliferation.

AIMS

To evaluate the immunohistochemical expression of ALDH1 as stem cell marker in the pathogenesis of colorectal carcinoma.

MATERIALS AND METHODS

This retrospective study included 71 colorectal specimens (49 colorectal carcinoma, 13 adenoma and 9 normal cases) that were collected from Pathology Department, Faculty of Medicine, Menoufia University during the period from 2011 to 2015. All cases were stained by ALDH 1 antibody. Survival data were available for 31cases.

RESULTS

There was a statistical significant association between epithelial positivity of ALDH1 and younger age (p=0.003), right sided tumour (p=0.038), presence of lymph node invasion (p= 0.04), ulcerating gross picture (p=0.01) and presence of vascular invasion (p=0.05). Moreover, there was statistical significant association between stromal positivity of ALDH1 and smaller tumour size (p=0.03) and inverse association between stromal expression of ALDH1 and grade of tumour (p=0.000) and perineural invasion (p= 0.05). Furthermore, there was an inverse significant relation between CD44 and ALDH1 expression (p=0.001). Univariate recurrence free survival analysis revealed the bad prognostic impact of high grade (p=0.03) and female sex (p=0.02) on patient outcome.

CONCLUSION

Epithelial expression of ALDH1 might be associated with poor prognosis while its stromal expression might be associated with good prognosis.

Immune targeting of cancer stem cells in gastrointestinal oncology

The cancer stem cell (CSC) hypothesis postulates that a sub-population of quiescent cells exist within tumors which are resistant to conventional cytotoxic/anti-proliferative therapies. It is these CSCs which then seed tumor relapse, even in cases of apparent complete response to systemic therapy. Therefore, therapies, such as immunotherapy, which add a specific anti-CSC strategy to standard cytoreductive treatments may provide a promising new direction for future cancer therapies. CSCs are an attractive target for immune therapies since, unlike chemotherapy or radiotherapy, immune effector cells do not specifically require target cells to be proliferating in order to effectively kill them. Although recent advances have been made in the development of novel systemic and targeted therapies for advanced gastro-intestinal (GI) malignancies, there remains an unmet need for durable new therapies for these refractory malignancies. Novel immunotherapeutic strategies targeting CSCs are in pre-clinical and clinical development across the spectrum of the immune system, including strategies utilizing adaptive immune cell-based effectors, innate immune effectors, as well as vaccine approaches. Lastly, since important CSC functions are affected by the tumor microenvironment, targeting of both cellular (myeloid derived suppressor cells and tumor-associated macrophages) and sub-cellular (cytokines, chemokines, and PD1/PDL1) components of the tumor microenvironment is under investigation in the immune targeting of CSCs. These efforts are adding to the significant optimism about the potential utility of immunotherapy to overcome cancer resistance mechanisms and cure greater numbers of patients with advanced malignancy.

Olfactory Receptor Family 7 Subfamily C Member 1 Is a Novel Marker of Colon Cancer-Initiating Cells and Is a Potent Target of Immunotherapy

PURPOSE

Cancer-initiating cells (CICs) are thought to be essential for tumor maintenance, recurrence, and distant metastasis, and they are therefore reasonable targets for cancer therapy. Cancer immunotherapy is a novel approach to target cancer. In this study, we aimed to establish novel CIC-targeting immunotherapy.

EXPERIMENTAL DESIGN

Colorectal cancer (CRC) CICs were isolated as side population (SP) cells. The gene expression profile of CRC CICs was analyzed by cDNA microarray and RT-PCR. Protein expression of olfactory receptor family 7 subfamily C member 1 (OR7C1) were analyzed by Western blot and immunohistochemical staining. The functions of OR7C1 were analyzed by gene overexpression and gene knockdown using siRNAs. OR7C1-positive cells were isolated by a flow cytometer and analyzed. CTLs specific for OR7C1 peptide were generated, and the antitumor effect was addressed by mice adoptive transfer model.

RESULTS

OR7C1 has essential roles in the maintenance of colon CICs, and the OR7C1-positive population showed higher tumorigenicity than that of the OR7C1-negative population, indicating that OR7C1 is a novel functional marker for colon CIC. Immunohistochemical staining revealed that OR7C1 high expression was correlated with poorer prognosis in CRC patients. OR7C1-derived antigenic peptide-specific CTLs showed specific cytotoxicity for CICs, and an OR7C1-specific CTL clone showed a greater antitumor effect than did a CTL clone targeting all cancer cells in a CTL adoptive transfer mouse model.

CONCLUSIONS

OR7C1 is a novel marker for colon CICs and can be a target of potent CIC-targeting immunotherapy. Clin Cancer Res; 22(13); 3298-309. ©2016 AACR.

Expression of SOX2 in oral squamous cell carcinoma and the association with lymph node metastasis

Oral squamous cell carcinomas (OSCCs) are a growing problem in the world. The various existing treatments have not markedly improved the survival rate of patients with OSCC during the past three decades. Novel treatment strategies are required. Sex determining region Y-box 2 (SOX2) is a transcription factor that is involved in the maintenance of embryonic stem cell pluripotency and in multiple developmental processes. SOX2 expression was indicated to act as a prognostic factor in various types of tumors, including breast, colorectal, gastric and lung cancer and glioblastoma, and as a link between malignancy and stemness. Cancer stem cells (CSCs) may be responsible for the genesis, growth and metastatic spread of tumors. The poor survival outcomes for OSCC patients may be attributable to a poor selection of target cells for treatment, as current oral cancer therapies are generally aimed at the global mass of tumor. Therefore, the consideration that novel approaches to oral cancer may be targeted using SOX2 and CSCs appears reasonable. In order to better understand the oncogenic roles and the corresponding signal transduction pathways of the SOX2 protein, the present study emphasizes the role of SOX2 in OSCC, including the proteins associated with OSCC, and reviews the literature regarding the role of SOX2 in lymph node metastasis. The aim of the present study is to provide a reference for future studies that engage in research on the aforementioned subject.

Expression levels of SOX2, KLF4 and brachyury transcription factors are associated with metastasis and poor prognosis in oral squamous cell carcinoma

The prognosis of oral squamous cell carcinoma (OSCC) patients is affected by tumor recurrence and metastasis, and cancer stem cells are hypothesized to be involved in these processes. Thus, the aim of the present study was to determine whether the expression levels of five stem cell-related transcription factors, sex determining region Y-box 2 (SOX2), octamer-binding transcription factor 4 (Oct4), avian myelocytomatosis viral oncogene homolog (c-Myc), Krüppel-like factor 4 (KLF4) and brachyury, are associated with metastasis and survival in OSCC. Immunohistochemistry was performed to analyze the expression of these proteins in biopsy specimens obtained from 108 OSCC patients. The results revealed that the expression of SOX2, Oct4, KLF4 and brachyury were significantly associated with lymph node metastasis (P=0.002, P=0.031, P=0.003 and P=0.007, respectively). In addition, the expression of KLF4 and brachyury were significantly associated with distant metastasis (P=0.014 and P=0.012, respectively). Furthermore, multivariate analysis revealed that SOX2 and KLF4 are predictive factors for lymph node metastasis [odds ratios (ORs), 4.526 and 4.851, respectively], and KLF4 is also a predictive factor for distant metastasis (OR, 9.607). In addition, OSCC patients with low co-expression of SOX2, KLF4 and brachyury exhibited a significantly lower disease-specific survival rate (78.6 vs. 100%; P=0.025; χ²=5.033) and disease-free survival rate (60.7 vs. 90.9%; P=0.015; χ²=5.897) when compared with OSCC patients with high co-expression of these factors. The results indicate that SOX2, KLF4 and brachyury serve important roles in tumor progression, and these transcription factors may thus represent clinically useful prognostic markers for OSCC.

Custom 4-Plex DiLeu Isobaric Labels Enable Relative Quantification of Urinary Proteins in Men with Lower Urinary Tract Symptoms (LUTS)

The relative quantification of proteins using liquid chromatography mass spectrometry (LC-MS) has allowed researchers to compile lists of potential disease markers. These complex quantitative workflows often include isobaric labeling of enzymatically-produced peptides to analyze their relative abundances across multiple samples in a single LC-MS run. Recent efforts by our lab have provided scientists with cost-effective alternatives to expensive commercial labels. Although the quantitative performance of these dimethyl leucine (DiLeu) labels has been reported using known ratios of complex protein and peptide standards, their potential in large-scale proteomics studies using a clinically relevant system has never been investigated. Our work rectifies this oversight by implementing 4-plex DiLeu to quantify proteins in the urine of aging human males who suffer from lower urinary tract symptoms (LUTS). Protein abundances in 25 LUTS and 15 control patients were compared, revealing that of the 836 proteins quantified, 50 were found to be differentially expressed (>20% change) and statistically significant (p-value <0.05). Gene ontology (GO) analysis of the differentiated proteins showed that many were involved in inflammatory responses and implicated in fibrosis. While confirmation of individual protein abundance changes would be required to verify protein expression, this study represents the first report using the custom isobaric label, 4-plex DiLeu, to quantify protein abundances in a clinically relevant system.

Role of the embryonic protein SOX2 in cholangiocarcinoma

SOX2 overexpression correlates with aggressive behavior and poor overall survival in cholangiocarcinoma (CCA). However, the cellular functions and precise role of SOX2 in CCA have not been elucidated. Here, we inserted SOX2 coding sequence to establish a CAA cell line which stably overexpressed SOX2. In vitro experiments showed that overexpression of SOX2 in cells was associated with increased cell proliferation, suppressed cell apoptosis, as well as enhanced cell migration and invasion. Our findings may lead to a better understanding of the biological effect of SOX2 and provide mechanistic insights for developing potential therapeutic strategies for CCA treatment.

Anti-proliferative but not anti-angiogenic tyrosine kinase inhibitors enrich for cancer stem cells in soft tissue sarcoma

BACKGROUND

Increasing studies implicate cancer stem cells (CSCs) as the source of resistance and relapse following conventional cytotoxic therapies. Few studies have examined the response of CSCs to targeted therapies, such as tyrosine kinase inhibitors (TKIs). We hypothesized that TKIs would have differential effects on CSC populations depending on their mechanism of action (anti-proliferative vs. anti-angiogenic).

METHODS

We exposed human sarcoma cell lines to sorafenib, regorafenib, and pazopanib and assessed cell viability and expression of CSC markers (ALDH, CD24, CD44, and CD133). We evaluated survival and CSC phenotype in mice harboring sarcoma metastases after TKI therapy. We exposed dissociated primary sarcoma tumors to sorafenib, regorafenib, and pazopanib, and we used tissue microarray (TMA) and primary sarcoma samples to evaluate the frequency and intensity of CSC markers after neoadjuvant therapy with sorafenib and pazopanib. Parametric and non-parametric statistical analyses were performed as appropriate.

RESULTS

After functionally validating the CSC phenotype of ALDHbright sarcoma cells, we observed that sorafenib and regorafenib were cytotoxic to sarcoma cell lines (P < 0.05), with a corresponding 1.4 - 2.8 fold increase in ALDHbright cells from baseline (P < 0.05). In contrast, we observed negligible effects on viability and CSC sub-populations with pazopanib. At low doses, there was progressive CSC enrichment in vitro after longer term exposure to sorafenib although the anti-proliferative effects were attenuated. In vivo, sorafenib improved median survival by 11 days (P < 0.05), but enriched ALDHbright cells 2.5 - 2.8 fold (P < 0.05). Analysis of primary human sarcoma samples revealed direct cytotoxicity following exposure to sorafenib and regorafenib with a corresponding increase in ALDHbright cells (P < 0.05). Again, negligible effects from pazopanib were observed. TMA analysis of archived specimens from sarcoma patients treated with sorafenib demonstrated significant enrichment for ALDHbright cells in the post-treatment resection specimen (P < 0.05), whereas clinical specimens obtained longitudinally from a patient treated with pazopanib showed no enrichment for ALDHbright cells (P > 0.05).

CONCLUSIONS

Anti-proliferative TKIs appear to enrich for sarcoma CSCs while anti-angiogenic TKIs do not. The rational selection of targeted therapies for sarcoma patients may benefit from an awareness of the differential impact of TKIs on CSC populations.

Novel tumor antigen-specific monoclonal antibody-based immunotherapy to eradicate both differentiated cancer cells and cancer-initiating cells in solid tumors

A growing body of experimental and clinical evidence strongly suggests that the resistance of cancer-initiating cells (CICs) to conventional therapies represents a major obstacle to the successful treatment of a malignant disease. To overcome this limitation a novel combinatorial tumor antigen (TA)-specific monoclonal antibody (mAb) strategy has been developed. In this strategy TA-specific mAbs are combined with chemotherapeutic agents and/or small molecules that inhibit aberrantly activated signaling pathways in cancer cells and especially in CICs. The in vitro results we have obtained indicate that this strategy is very effective in eradicating both differentiated cancer cells and CICs in several types of malignant disease. If the in vitro results have in vivo relevance, the strategy we have designed may have an impact on the treatment of malignant diseases.

The impact of Aldehyde dehydrogenase 1 expression on prognosis for metastatic colon cancer

BACKGROUND

Cancer stem cells may be associated with tumor progression and prognosis for colon cancer. We hypothesized that expression of Aldehyde dehydrogenase 1 (ALDH1) would increase with tumor progression and be associated with survival.

METHODS

Tissue was obtained from resection specimens for isolation of cancer stem cells. In addition, paraffin blocks from resected colon cancers with normal colon, primary tumor, and lymph node and liver metastasis from 2000 to 2010 were identified and stained with ALDH1.

RESULTS

In in vitro models (adherent and tumor spheres) ALHD1+ cells grew more efficiently than ALDH1- cells. ALDH1 expression was highest in peritumoral crypt cells (0.137 μm(2), 95% confidence interval [CI] 0.125-0.356) and normal crypts (median 0.091 μm(2), 95% CI 0.064-0.299) followed by lymph node metastasis (median 0.025 μm(2), 95% CI 0-0.131) and the primary cancers (median 0.014 μm(2), 95% CI 0.0123-0.154). Samples were divided into high and low ALDH1 expression. Survival was associated with expression in the primary tumor (9 versus 23 mo, P = 0.0016) expression but not peritumoral tissue (21 versus 20.5 mo, P = 0.32), normal colon (19 versus 27 mo, P = 0.289), or lymph node metastasis (23 versus 21 mo, P = 0.69). On univariate analysis, ALDH1 expression and grade were associated with survival but ages, number of lymph node metastasis, race, or grade were not associated. On multivariate analysis, only ALDH1 status continued to be associated with survival, odds ratio 4.4, and P = 0.011.

CONCLUSIONS

ALDH1 is indicative of stemness and is a biomarker marker in colon cancer. Expression did not increase with progression from normal colon to primary tumors and metastasis.

Clinicopathologic significance of Sox2, CD44 and CD44v6 expression in intrahepatic cholangiocarcinoma

Embryonic stem cells (ESC) and cancer stem cells (CSC) have a capacity for self-renewal and differentiation into multiple cell lineages. Sox2 plays a critical role in ESC and has been shown to participate in carcinogenesis and tumor progression in many human cancers. CD44 and CD44v6 are putative CSC markers and their association with tumor progression, metastasis, and tumor relapse after treatment has been demonstrated. We evaluated the immunoexpression of Sox2, CD44, and CD44v6 in 85 cases of Intrahepatic cholangiocarcinomas (IHCC) and assessed their prognostic significance. Sox2 expression showed a significant association with lymph node metastasis (p = 0.025), T4 stage (p = 0.046), and worse overall survival (p = 0.047). Greater expression of Sox2 was observed in IHCC with poor differentiation, vascular invasion, and stage IV, without statistical significance (p > 0.05). CD44 expression showed an association with periductal infiltrative type (p = 0.034), poor differentiation (p = 0.012), and vascular invasion (p = 0.009). CD44v6 expression was evident in patients with stage IV (p = 0.019). These results demonstrated that Sox2 expression is associated with aggressive behavior and poor overall survival in IHCC.

ALDH1-high ovarian cancer stem-like cells can be isolated from serous and clear cell adenocarcinoma cells, and ALDH1 high expression is associated with poor prognosis

Cancer stem-like cells (CSCs)/cancer-initiating cells (CICs) are defined as a small population of cancer cells that have high tumorigenicity. Furthermore, CSCs/CICs are resistant to several cancer therapies, and CSCs/CICs are therefore thought to be responsible for cancer recurrence after treatment and distant metastasis. In epithelial ovarian cancer (EOC) cases, disease recurrence after chemotherapy is frequently observed, suggesting ovarian CSCs/CICs are involved. There are four major histological subtypes in EOC, and serous adenocarcinoma and clear cell adenocarcinoma are high-grade malignancies. We therefore analyzed ovarian CSCs/CICs from ovarian carcinoma cell lines (serous adenocarcinoma and clear cell adenocarcinoma) and primary ovarian cancer cells in this study. We isolated ovarian CSCs/CICs as an aldehyde dehydrogenase 1 high (ALDH1(high)) population from 6 EOC cell lines (3 serous adenocarcinomas and 3 clear cell adenocarcinomas) by the ALDEFLUOR assay. ALDH1(high) cells showed greater sphere-forming ability, higher tumorigenicity and greater invasive capability, indicating that ovarian CSCs/CICs are enriched in ALDH1(high) cells. ALDH1(high) cells could also be isolated from 8 of 11 primary ovarian carcinoma samples. Immunohistochemical staining revealed that higher ALDH1 expression levels in ovary cancer cases are related to poorer prognosis in both serous adenocarcinoma cases and clear cell adenocarcinoma cases. Taken together, the results indicate that ALDH1 is a marker for ovarian CSCs/CICs and that the expression level of ALDH1 might be a novel biomarker for prediction of poor prognosis.