Prognostic Impact of ALDH1 Expression in Transitional Cell Carcinoma of the Renal Pelvis

AIM

To investigate the clinical significance of aldehyde dehydrogenase 1 (ALDH1) expression in the assessment of the pathological outcomes and prognosis of carcinoma of the renal pelvis through examination of ALDH1 expression in pathological specimens.

MATERIALS AND METHODS

A total of 114 patients with carcinoma of the renal pelvis who underwent radical nephroureterectomy at the First Hospital of Peking University between September 2004 and August 2007 with continuity in data were included in this study. The expression of ALDH1 was examined in pathological specimens via immunohistochemistry, and was statistically analyzed in combination with corresponding clinical and pathological information.

RESULTS

The pathological specimens from 37 patients (32.5%) exhibited positive ALDH1 expression, showing correlation with T stage (p=0.001) and G grade (p=0.010), as well as lymphatic and vascular infiltration (p=0.003), but these specimens did not correlate with tumor multi-focality (p=0.398). The univariate analysis showed that tumor grade (p=0.001) and ALDH1 positive expression (p<0.001), as well as lymphatic and vascular infiltration (p=0.017) correlated with prognosis, and this analysis also showed that tumour, node and metastasis (TNM) stage (p=0.085), as well as occurrence of multiple tumors (p=0.166) had no significant correlation with prognosis. Multivariate analysis indicated advanced G grade (p=0.006) and ALDH1 expression as independent predictive factors for poor prognosis. A significant correlation was observed between positive ALDH1 expression and tumor relapse following radical resection (p<0.001).

CONCLUSION

The cancer stem-like cell marker ALDH1 can be used as a predictive factor for adverse pathological outcomes and prognosis in transitional cell carcinoma. of the renal pelvis. Cancer stem cell theory plays an important role in the clinical study of transitional cell carcinoma of the upper urinary tract.

Immunohistochemical evaluation of stem cell markers and signal transducer and activator of transcription 6 (STAT6) in solitary fibrous tumors

Solitary fibrous tumors (SFT) are fibroblastic, ubiquitous mesenchymal tumors. Although several SFT studies have been conducted, the cell of origin of SFT remains controversial and reliable diagnostic markers are needed for SFT identification for proper prognosis and therapeutics. To analyze the immunophenotype of SFT for the identification of specific diagnostic markers and the cell of origin of this tumor, we performed an immunohistochemical study of stem cell markers [aldehyde dehydrogenase 1 (ALDH1), CD29, CD44, CD133, and nestin] and signal transducer and activator of transcription 6 (STAT6) in 18 cases of SFT. The results demonstrated that ALDH1 was present in 16 cases (16/18), STAT6 in 13 cases (13/18), CD44 in 8 cases (8/18), and CD29 in 1 case (1/18), whereas CD133 and nestin were absent in all cases (0/18). Our results indicate that combination with ALDH1 and STAT6 can improve the diagnostic value of CD34 for SFT. The immunohistochemical findings for stem cell surface markers indicate that SFT may originate from stem cells and that ALDH1 plays an important role in the development of SFT.

Molecular heterogeneity in adjacent cells in triple-negative breast cancer

Purpose

This study interrogates the molecular status of individual cells in patients with triple-negative breast cancers and explores the molecular identification and characterization of these tumors to consider the exploitation of a potential-targeted therapeutic approach.

Patients and methods

Hyperspectral immunologic cell by cell analysis was applied to touch imprint smears obtained from fresh tumors of breast cancer patients.

Results

Cell by cell analysis confirms significant intratumoral molecular heterogeneity in cancer markers with differences from polymerase chain reaction marker reporting. The individual cell heterogeneity was recognized in adjacent cells examined with panels of ten molecular markers in each single cell and included some markers that are considered to express “stem-cell” character. In addition, heterogeneity did not relate either to the size or stage of the primary tumor or to the site from within the cancer.

Conclusion

There is a very significant molecular heterogeneity when “adjacent cells” are examined in triple-negative breast cancer, thereby making a successful targeted approach unlikely. In addition, it is not reasonable to consider that these changes will provide an answer to tumor dormancy.

Bovine CD49 positive-cell subpopulation remarkably increases in mammary epithelial cells that retain a stem-like phenotype

We previously proved that adult stem cells reside in the bovine mammary gland and possess an intrinsic potential to generate a functional mammary outgrowth. The aim of this study was to investigate on the immunophenotyping features retained by mammary stem-like cells detected in long term culture. Flow cytometry analysis showed different subpopulations of mammary epithelial cells emerging according to the timing of cell culture. CD49f(+)-cells significantly increased during the culture (p<0.01) and a similar trend was observed, even if less regular, for CD29(+) and ALDH1 positive cell populations. No difference during the culture was observed for CD24 positive cells but after 35 days of culture a subset of cells, CD49f positive, still retained regenerative capabilities in in vivo xenotransplants. These cells were able to form organized pseudo-alveoli when transplanted in immunodeficient mice. These results prove the presence of a multipotent cell subpopulation that retain a strong epithelial induction, confirmed in in vivo xenotransplants with a presumable in vitro expansion of the primitive population of adult mammary stem cells.

Aldehyde dehydrogenase 1 expression correlates with clinicopathologic features of patients with breast cancer: a meta-analysis

A number of studies have investigated the relationship between aldehyde dehydrogenase 1 (ALDH1) expression and the clinical pathological features of the patients with breast cancer. However, conclusions reported by different parties seem to be inconsistent. We have reviewed published studies and carried out this meta-analysis to provide credible results. We searched PubMed for articles published in English until September 12, 2014. Our main analyses were focused on the association between ALDH1 and the clinical pathological features, such as age, tumor size, nodal status, lymphovascular invasion, histological grade, and the expression of ER, PR, and HER2 by meta-analysis methods. If heterogeneity was observed, we used random effects model to calculate the overall odds ratios, otherwise fixed effects model was used. Twenty-one eligible studies were included in the present meta-analysis. From the pooled analyses, there was significant association between ALDH1 expression and histological grade (low vs. intermediate: pooled OR = 1.51, 95% CI: 1.09-2.10, P = 0.01; intermediate vs. high: pooled OR = 1.86, 95% CI: 1.12-3.07, P = 0.02), ER expression (pooled OR = 0.41, 95% CI: 0.29-0.58, P < 0.00001), and PR expression (pooled OR = 0.56, 95% CI: 0.40-0.77, P = 0.0004). No clear correlation was found between ALDH1 expression and age, tumor size, lymph node (LN) metastasis, lynphovascular invasion, and HER2 expression (P > 0.05). Despite the inconsistency in the published reports, this meta-analysis provides credible evidence to support the association between ALDH1 and breast cancer. However, it is necessary to conduct large sample studies using standardized and well-matched controls.

Differential Expression of Cancer Stem Cell Markers ALDH1 and CD133 in Various Lung Cancer Subtypes

Cancer stem cells (CSCs) are hypothesized to be the main culprit of lung cancer progression. Clinicopathological significance of stem cell markers CD133 and ALDH1 in a large group of lung cancer patients was evaluated. ALDH1 and CD133 had higher expression levels in the NSCLC compared to the SCLC. Over-expression of both ALDH1 and CD133 markers was exclusively found in SCC and ADC. Low level of ALDH1 expression was strongly correlated with poor differentiation in ADC cases. Thus, ALDH1(high)/CD133(high) phenotype can be considered as a CSC marker in some lung cancer subtypes.

The clinicopathological and prognostic significance of CD24, CD44, CD133, ALDH1 expressions in invasive ductal carcinoma of the breast: CD44/CD24 expression in breast cancer

BACKGROUND

Recently, there are several studies about cancer stem cells (CSC), indicating that they are the cells that initiate the tumor, provide progression, metastasis and responsible for the aggressive tumor behavior.

MATERIALS AND METHODS

The purpose of this study is to investigate the expressions of CD24, CD44, their different combinations, ALDH1 and CD133 in invasive ductal carcinoma. Their relationships with clinicopathologic parameters, such as tumor grade, lymphovascular invasion, tumor size, axillary lymph node involvement, stage, hormone receptors, HER2 expression, basal like tumors, triple negative status and prognosis were also investigated. Tissue microarray method was used to investigate ımmunohistochemical CD24, CD44, ALDH1 and CD133 expressions in 105 invasive ductal carcinoma cases.

RESULTS

CD133 expression was significantly associated with tumor size (p=0.023) and stage (p=0.009). CD133 expression was decreased in tumors with larger tumor size, higher stage and lymphovascular invasion. CD133 expression was positively correlated with CD44 (r=0.212, p=0.032) and CD44(+)/CD24(+) (r=0.202, p=0.040) expressions. CD44, CD24 and ALDH1 expressions showed no significant relationship and correlation with clinicopathologic features. There was a significant relationship (p=0.048) between CD44(+)/CD24(-/low) phenotype and basal like tumors. EGFR expression was positively correlated with CD44(+)/CD24(-/low) phenotype (r=0.211, p=0.036).

CONCLUSIONS

Basal like tumors are enriched for CSCs with CD44(+)/CD24(-/low) phenotype. CD133 can detect a different population of CSC in breast carcinoma.

ALDH1 might influence the metastatic capability of HeLa cells

Recent data suggest that tumor persistence and recurrence could be caused by the presence of cancer stem cells (CSCs). Aldehyde dehydrogenase 1 (ALDH1) has been implicated in cancer pathogenesis and used as a CSC marker. We previously reported that cervical carcinoma contains a small subpopulation of cells expressing ALDH1 [1]. In this study, we used small interfering RNA to suppress ALDH1 expression and introduced an ALDH1 reporting vector into HeLa cells followed by various in vitro assays. We showed that knockdown of ALDH1 expression reduced the cell migration ability of HeLa cells, whereas augmented expression of ALDH1 increased cell migration. However, there was no difference in the cellular proliferation, apoptosis, cell cycle, and invasion. These results indicate that ALDH1 is directly involved in HeLa migration.

Relation of stem cell markers ALDH1 and CD44 with clinicopathological factors in urothelial carcinomas of urinary bladder

Molecular studies are ongoing in regards to superficial urothelial carcinoma of the bladder (UCB) either to define targeted therapy or to better select aggressive therapy candidates and also to delineate the outcome of the disease. In this study, we aimed to present the impact of ALDH1 and CD44 as stem cell markers in tumorigenesis and their prognostic value in urothelial carcinoma. We investigated ALDH1 and CD44 immunohistochemically in paraffin-embedded material of 125 non-muscle-invasive (NMI) cases in 163 UCB patients. In the NMI-UCB subgroup, we found ALDH1 to be significantly correlated with all poor prognostic factors, including high stage (≥pT2), high grade, recurrence and progression development and poor survey (P=0.001) in contrast to CD44 expression (P>0.05). Although ALDH1 expression had a good correlation with a poor clinical course of UCB, it could be used as a molecular marker to determine the best treatment strategy and could contribute to the development of targeted therapies.

Evidence for epithelial-mesenchymal transition in cancer stem-like cells derived from carcinoma cell lines of the cervix uteri

The cancer stem cell (CSC) paradigm is one possible way to understand the genesis of cancer, and cervical cancer in particular. We quantified and enriched ALDH1(+) cells within cervical cancer cell lines and subsequently characterized their phenotypical and functional properties like invasion capacity and epithelial-mesenchymal transition (EMT). ALDH1 expression in spheroid-derived cells (SDC) and the parental monolayer-derived cell (MDC) line was compared by flow-cytometry. Invasion capability was evaluated by Matrigel assay and expression of EMT-related genes Twist 1, Twist 2, Snail 1, Snail 2, Vimentin and E-cadherin by real-time PCR. ALDH1 expression was significantly higher in SDC. ALDH1(+) cells showed increased colony-formation. SDC expressed lower levels of E-cadherin and elevated levels of Twist 1, Twist 2, Snail 1, Snail 2 and Vimentin compared to MDC. Cervical cancer cell lines harbor potential CSC, characterized by ALDH1 expression as well as properties like invasiveness, colony-forming ability, and EMT. CSC can be enriched by anchorage-independent culture techniques, which may be important for the investigation of their contribution to therapy resistance, tumor recurrence and metastasis.

The PAX2-null immunophenotype defines multiple lineages with common expression signatures in benign and neoplastic oviductal epithelium

The oviducts contain high-grade serous cancer (HGSC) precursors (serous tubal intraepithelial neoplasia or STINs), which are γ-H2AX(p) - and TP53 mutation-positive. Although they express wild-type p53, secretory cell outgrowths (SCOUTs) are associated with older age and serous cancer; moreover, both STINs and SCOUTs share a loss of PAX2 expression (PAX2(n) ). We evaluated PAX2 expression in proliferating adult and embryonic oviductal cells, normal mucosa, SCOUTs, Walthard cell nests (WCNs), STINs, and HGSCs, and the expression of genes chosen empirically or from SCOUT expression arrays. Clones generated in vitro from embryonic gynaecological tract and adult Fallopian tube were Krt7(p) /PAX2(n) /EZH2(p) and underwent ciliated (PAX2(n) /EZH2(n) /FOXJ1(p) ) and basal (Krt7(n) /EZH2(n) /Krt5(p) ) differentiation. Similarly, non-ciliated cells in normal mucosa were PAX2(p) but became PAX2(n) in multi-layered epithelium undergoing ciliated or basal (WCN) cell differentiation. PAX2(n) SCOUTs fell into two groups: type 1 were secretory or secretory/ciliated with a 'tubal' phenotype and were ALDH1(n) and β-catenin(mem) (membraneous only). Type 2 displayed a columnar to pseudostratified (endometrioid) phenotype, with an EZH2(p) , ALDH1(p) , β-catenin(nc) (nuclear and cytoplasmic), stathmin(p) , LEF1(p) , RCN1(p) , and RUNX2(p) expression signature. STINs and HGSCs shared the type 1 immunophenotype of PAX2(n) , ALDH1(n) , β-catenin(mem) , but highly expressed EZH2(p) , LEF1(p) , RCN1(p) , and stathmin(p) . This study, for the first time, links PAX2(n) with proliferating fetal and adult oviductal cells undergoing basal and ciliated differentiation and shows that this expression state is maintained in SCOUTs, STINs, and HGSCs. All three entities can demonstrate a consistent perturbation of genes involved in potential tumour suppressor gene silencing (EZH2), transcriptional regulation (LEF1), regulation of differentiation (RUNX2), calcium binding (RCN1), and oncogenesis (stathmin). This shared expression signature between benign and neoplastic entities links normal progenitor cell expansion to abnormal and neoplastic outgrowth in the oviduct and exposes a common pathway that could be a target for early prevention.

The prognostic role of the cancer stem cell marker aldehyde dehydrogenase 1 in head and neck squamous cell carcinomas: a meta-analysis

OBJECTIVE

This study aimed to investigate the correlation between aldehyde dehydrogenase 1 (ALDH1)-positive head and neck squamous cell carcinomas (HNSCC) and clinicopathological features and its effect on survival. A meta-analysis based on published studies was conducted to accurately evaluate the association between the presence of cancer stem cells (CSCs) in clinical samples and clinical outcome.

METHODS

A search in the PubMed, EMBASE, and Wanfang databases (up to May 1, 2014) was conducted. Publications assessing the clinical or prognostic significance of ALDH1 expression in HNSCC were identified and reviewed until May 1, 2014. A meta-analysis was performed to clarify the association between ALDH1 expression and clinical outcomes.

RESULTS

A total of 9 publications satisfied the criteria and comprised 749 cases. ALDH1 expression was not significantly associated with tumor T stage [I+II vs. III+IV; odds ratio (OR)=1.23, 95% confidence interval (CI)=0.70-2.15, P=0.48]. However, in the identified studies, ALDH1 expression was highly correlated with tumor differentiation (G1+G2 vs. G3; OR=3.30, 95% CI=1.92-5.67, P<0.001), lymph node metastasis (OR=4.07, 95% CI=1.18-14.10, P=0.03), decreased overall survival [relative risk (RR)=1.84, 95% CI=1.43-2.36, P<0.0001], and decreased disease-free survival (RR=2.34, 95% CI=1.37-4.00, P=0.002).

CONCLUSION

ALDH1-positive HNSCC patients had worse prognosis, which was associated with common clinicopathological features and poor prognostic factors.

TRPM7 channels regulate glioma stem cell through STAT3 and Notch signaling pathways

Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor in adults with median survival time of 14.6 months. A small fraction of cancer stem cells (CSC) initiate and maintain tumors thus driving glioma tumorigenesis and being responsible for resistance to classical chemo- and radio-therapies. It is desirable to identify signaling pathways related to CSC to develop novel therapies to selectively target them. Transient receptor potential cation channel, subfamily M, member 7, also known as TRPM7 is a ubiquitous, Ca(2+) and Mg(2+) permeable ion channels that are special in being both an ion channel and a serine/threonine kinase. In studies of glioma cells silenced for TRPM7, we demonstrated that Notch (Notch1, JAG1, Hey2, and Survivin) and STAT3 pathways are down regulated in glioma cells grown in monolayer. Furthermore, phospho-STAT3, Notch target genes and CSC markers (ALDH1 and CD133) were significantly higher in spheroid glioma CSCs when compared with monolayer cultures. The results further show that tyrosine-phosphorylated STAT3 binds and activates the ALDH1 promoters in glioma cells. We found that TRMP7-induced upregulation of ALDH1 expression is associated with increases in ALDH1 activity and is detectable in stem-like cells when expanded as spheroid CSCs. Finally, TRPM7 promotes proliferation, migration and invasion of glioma cells. These demonstrate that TRPM7 activates JAK2/STAT3 and/or Notch signaling pathways and leads to increased cell proliferation and migration. These findings for the first time demonstrates that TRPM7 (1) activates a previously unrecognized STAT3→ALDH1 pathway, and (2) promotes the induction of ALDH1 activity in glioma cells.

Cancer stem cells in Helicobacter pylori infection and aging: Implications for gastric carcinogenesis

AIM: To demonstrated the combined effects of aging and carcinogen treatment on cancer stem/stem-like cells (CSCs) of gastric mucosa in an animal model.

METHODS: In this study we investigated the effects of aging and Helicobacter pylori (H. pylori) inflammation as a model for inflammation induced carcinogenesis in human and rat gastric mucosa samples. In aging studies, we compared 4-mo old (young) with 22 mo (aged) old Fischer-344 rats. For human studies, gastric biopsies and resection specimens representing normal mucosa or different stages of H. pylori gastritis and gastric adenocarcinomas were used for determining the expression of stem cell markers CD166, ALDH1 and LGR5. In addition we performed immunofluorescent double labeling for B-catenin and Lgr5 in both rat and human gastric tissues to examine the status of Wnt signaling in these cells.

RESULTS: CSC markers ALDH1, LGR5, and CD166 were expressed in very low levels in normal human gastric mucosa or young rat gastric mucosa. In contrast, level of expression for all three markers significantly increased in H. pylori gastritis and gastric adenocarcinomas as well as in normal gastric mucosa in aged rats. We also observed cytoplasmic B-catenin staining in both aged rat and human H. pylori inflamed gastric mucosa, which were found to be colocalized with Lgr5 immunoreactive cells. The increased number of ALDH1, CD166 and LGR5 positive cells in H. pylori gastritis indicates that increased number of stem-like cells in gastric mucosa is an early event, and may constitute an important step in the progression to neoplasia.

CONCLUSION: Our observation of the age-related increase in cancer stem/stem-like cells in the gastric mucosa may explain the increased incidence of gastric cancer during aging. Combination of aging and H. pylori infection may have additive effects in progression to neoplasia.

Correlations of ALDH1 expression with molecular subtypes and ABCG2 in breast cancer

OBJECTIVE

To investigate the correlations of aldehyde dehydrogenase 1 (ALDH1) expression with the molecular subtypes and ATP-binding cassette subfamily G member 2 (ABCG2) in breast cancer.

METHODS

The specimens from 179 cases of breast cancer were divided into five molecular subtypes according to the immunological markers (ER, PR, HER2 and CK5/6), which were luminal A, luminal B, Her2-enriched, basal-like and breast-like subtype, respectively. The expressions of ALDH1 and ABCG2 of the specimens were detected with immunohistochemical staining, and the relationship between them as well as their relations with the clinicopathological factors of breast cancer was analyzed.

RESULTS

Of the 179 cases of breast cancer, ALDH1 positive expression was present in 43 cases (24.0%). The AIDH1 expression rate showed significant difference among the different molecular subtypes of breast cancer (P=0.003). The positive expression rate of ALDH1 was 16.7% (17/102) in luminal A subtype, 21.4% (3/14) in luminal B subtype, 54.5% (13/22) in Her2-enriched subtype, 33.3% (8/24) in basal-like subtype, and 17.6% (3/17) in breast-like subtype, respectively. The positive expression of ALDH1 had no significant relation with the ABCG2 expression (P=0.052). Both ALDH1 and ABCG2 expressions were related to the administration of preoperative chemotherapy (P=0.027 and P=0.033) and ALDH1 expression was related to the HER2 expression (P=0.006).

CONCLUSIONS

With a high expression level of ALDH1, HER2 overexpression, basal-like and ABCG2-positive types were associated with poor outcomes and treatment resistance in breast cancer. The expression of ALDH1 has no obvious relation with ABCG2.

Expression of ALDH1 and TGFβ2 in benign and malignant breast tumors and their prognostic implications

The specific mechanism underlying the role of putative stem cell marker aldehyde dehydrogenase 1 (ALDH1) playing in development and progression of breast cancer is currently unclear. Transforming growth factor β (TGFβ) signaling pathway is reported to be activated in most cancers. Thus a study was initiated to explore possible differences and correlation of ALDH1 and TGFβ2 expression in the most common malignant and benign tumors of the breast in Chinese women. Samples of 75 breast cancer tissues, 30 paracancerous normal tissues, and 39 fibroadenoma breast tissues were investigated for the expression of ALDH1 and TGFβ2 using immunohistochemistry. The positive rates of ALDH1 and TGFβ2 protein were 62.67% and 66.67%, respectively, in breast cancer tissues, which were significantly higher than that in normal fibroadenoma breast (P<0.05) and paracancerous tissues (P<0.01). ALDH1 and TGFβ2 status were significantly associated with tumor histological grade and receptor status (P<0.05). Expression of ALDH1 was found to be positively correlative to TGFβ2 in breast cancer (r = 0.33, P<0.01). Expression of both proteins remained significantly associated with reduced overall survival (OS) by univariate analysis (P<0.05). Multivariate Cox regression analysis showed that ALDH1 expression, tumor stage, and lymph node status are independent prognostic factors in invasive breast cancer patients. Thus ALDH1 and TGFβ2 play important roles in the development of breast cancer. The ALDH1 phenotype is an independent predictor of poor prognosis, and TGFβ2 signaling pathway activation might be involved in the pathological regulation of ALDH1 in breast cancer.

Aldehyde dehydrogenase1 immunohistochemical staining in primary breast cancer cells independently predicted overall survival but did not correlate with the presence of circulating or disseminated tumors cells

PURPOSE

We hypothesized that aldehyde dehydrogenase 1 (ALDH1) staining in breast cancer tumor cells might be a simple surrogate for the presence of circulating tumor cells (CTCs) or disseminated tumor cells (DTCs).

EXPERIMENTAL DESIGN

Whole tissue primary tumor sections from 121 patients enrolled in a clinical trial assessing CTCs and DTCs at the time of surgery were stained for ALDH1 and scored by a dedicated breast pathologist blinded to outcome. Clinical data was extracted and staining was correlated to clinical variables and outcome by Fisher's exact test, the Log rank test and Cox proportional hazards regression analysis respectively. P < 0.05 was considered significant.

RESULTS

ALDH1 staining in tumor cells was present in 12% of cases (15/121). In univariate analysis, ALDH1 tumor staining predicted worse overall survival (71% vs. 91% at 5 years P = 0.0074) and was an independent predictor on multivariable analysis of worse overall survival, (HR 4.93) after adjusting for stage, ER, grade, LVI, age and neoadjuvant chemotherapy (P = 0.04). ALDH1 was significantly associated with estrogen receptor (ER) negative (P value = 0.029) primary tumors but not the presence of CTCs or DTCs by multivariate logistic regression. Positive ALDH staining in non-tumor cells of any pattern or morphology was common but did not correlate with CTCs or DTCs, other clinical variables, or outcome.

CONCLUSION

ALDH1 tumor staining was associated with ER -negative breast cancer and was an independent predictor of OS. However, it did not correlate to putative cancer stem cell surrogates CTCs and/or DTCs.

Co-expression of stem cell markers ALDH1 and CD44 in non-malignant and neoplastic lesions of the breast

BACKGROUND/AIM

The Cancer Stem Cell (CSC) model proposes that cancer is driven by a cellular component which possesses stem cell (SC) properties, cancer stem cells (CSCs), a distinct cell-type which is tumorigenic and capable of invasion and metastasis. Enzymatic activity of aldehyde dehydrogenase-1 (ALDH1), a de-toxifying enzyme that oxidizes intracellular aldehydes, has been used as a marker of normal and malignant breast stem cells (BSCs). CD44-transmembrane protein has already been shown to possess the ability to identify breast epithelial cells with stem properties.

MATERIALS AND METHODS

In order to compare two of the currently most reliable BSCs markers, ALDH1 and CD44, and to correlate their expression within different breast lesions, 190 samples from breast cancer specimens were analyzed by tissue microarrays.

RESULTS

ALDH1 expression was observed in 85.43% and CD44 in 90.3% of all samples. No overexpression was observed for ALDH1 between invasive tumors, ductal carcinomas in situ and non-malignant lesions of breast, although ALDH1 had a significant negative correlation with estrogen-receptor (ER) and progesterone-receptor (PR) status (p=0.002 and p=0.001, respectively) and a positive correlation with CD44 (p<0.001). Moreover, combined overexpression of ALDH1 and CD44 was observed in ductal in situ tumors (p<0.001).

CONCLUSION

The combined overexpression of these markers in ductal carcinomas in situ is in agreement with the CSC model in breast cancer.

Aldehyde dehydrogenase-1 predicts favorable prognosis in patients with vulvar squamous cell carcinoma

BACKGROUNDS

Aldehyde dehydrogenase-1 (ALDH1) has been considered as a potential cancer stem cell marker in different types of cancer. In the present study, we investigated the expression of ALDH1 in vulvar squamous cell carcinoma, and evaluated its correlation with clinicopathological factors in patients suffering from this disease.

MATERIALS AND METHODS

One hundred and fifty-four patients with vulvar squamous cell carcinoma, together with their verified histopathological and complete clinical data in Norway were included in the study. All paraffin-embedded samples of the primary vulvar carcinoma were recruited. The presence of ALDH1 was detected by immunohistochemistry and compared against commonly recognized prognostic factors.

RESULTS

By immunohistochemical staining, the expression of ALDH1 was observed in 10/154 (6.5%) vulvar squamous cell carcinomas, while being extensively expressed in the suprabasal cells in normal vulvar epithelia from patients with benign gynecological disease and non-malignant epithelia adjacent to the tumor cells. In addition, ALDH1 was highly expressed in stromal fibroblasts, blood vessels and keratinized pearl of the carcinoma in all the samples. Patients with ALDH1-positive tumors had a significantly longer disease-specific survival (p=0.042).

CONCLUSION

Contrary to the characteristics of cancer stem cells shown in other types of cancer with positive expression of ALDH1, the positive expression of ALDH1 in patients with vulvar squamous cell carcinoma indicates a significantly better prognosis. Furthermore, there is a trend that the expression of ALDH1 is associated with better histological differentiation.

Studies on the expression of linalool synthase using a promoter-β-glucuronidase fusion in transgenic Artemisia annua

Artemisinin, an antimalarial endoperoxide sesquiterpene, is synthesized in glandular trichomes of Artemisia annua L. A number of other enzymes of terpene metabolism utilize intermediates of artemisinin biosynthesis, such as isopentenyl and farnesyl diphosphate, and may thereby influence the yield of artemisinin. In order to study the expression of such enzymes, we have cloned the promoter regions of some enzymes and fused them to β-glucuronidase (GUS). In this study, we have investigated the expression of the monoterpene synthase linalool synthase (LIS) using transgenic A. annua carrying the GUS gene under the control of the LIS promoter. The 652bp promoter region was cloned by the genome walker method. A number of putative cis-acting elements were predicted indicating that the LIS is driven by a complex regulation mechanism. Transgenic plants carrying the promoter-GUS fusion showed specific expression of GUS in T-shaped trichomes (TSTs) but not in glandular secretory trichomes, which is the site for artemisinin biosynthesis. GUS expression was observed at late stage of flower development in styles of florets and in TSTs and guard cells of basal bracts. GUS expression after wounding showed that LIS is involved in plant responsiveness to wounding. Furthermore, the LIS promoter responded to methyl jasmonate (MeJA). These results indicate that the promoter carries a number of cis-acting regulatory elements involved in the tissue-specific expression of LIS and in the response of the plant to wounding and MeJA treatment. Southern blot analysis indicated that the GUS gene was integrated in the A. annua genome as single or multi copies in different transgenic lines. Promoter activity analysis by qPCR showed that both the wild-type and the recombinant promoter are active in the aerial parts of the plant while only the recombinant promoter was active in roots. Due to the expression in TSTs but not in glandular trichomes, it may be concluded that LIS expression will most likely have little or no effect on artemisinin production.

Elevated intrinsic cancer stem cell population in human papillomavirus-associated head and neck squamous cell carcinoma

BACKGROUND

Human papillomavirus 16 (HPV16) is a major risk factor for the development of head and neck squamous cell carcinoma (HNSCC), particularly the development of oropharyngeal squamous cell carcinoma (OPSCC). Cancer stem cells (CSCs) are resistant to conventional therapies, and it is postulated that they are responsible for disease recurrence and/or progression. Because the prognoses of patients with HPV16-positive and HPV-negative HNSCC are distinct, the authors sought to determine whether differences in the number of CSCs could account for this clinical observation.

METHODS

CSC populations in HPV16-positive and HPV-negative HNSCC were assessed using a proprietary assay based on expression of the enzyme aldehyde dehydrogenase (ALDH), an in vitro tumorsphere formation assay, and an in vivo limiting cell dilution in nonobese diabetic/severe combined immunodeficiency mice. A high-density tissue microarray was stained with ALDH1, a CSC marker, to determine the association between CSCs and HPV16-positive/HPV-negative OPSCC.

RESULTS

HPV16-positive HNSCC had a greater intrinsic CSC pool than HPV-negative HNSCC. Inactivation of p53 has been identified as a major mechanism for the elevated CSC population in HPV16-positive HNSCC. In vivo limiting cell dilution experiments using tumors from patients with HPV16-positive and HPV-negative OPSCC indicated that the CSC frequency was 62.5-fold greater in an HPV16-positive OPSCC tumor than in an HPV-negative OPSCC tumor. Primary tumors from patients with HPV16-positive OPSCC were associated with elevated tumor ALDH1 staining, further extending the association between HPV16 and CSCs.

CONCLUSIONS

The current data and the clinical observation that patients with HPV16-positive HNSCC respond more favorably to current treatment paradigms than patients with HPV-negative HNSCC support the suggestion that CSC phenotype is not homogeneous. Therefore, the reliance on the CSC number may be insufficient to accurately assess the potential of a particular tumor for disease recurrence and/or progression.

Ovarian cancer stem cells: are they real and why are they important?

The cancer stem cell hypothesis has been put forward as a paradigm to describe varying levels of aggressiveness in heterogeneous tumors. Specifically, many subpopulations have been clearly demonstrated to possess increased tumorigenicity in mice, broad differentiating capacity, and resistance to therapy. However, the extent to which these experimental findings are potentially clinically significant is still not clear. This review will describe the principles of this emerging hypothesis, ways in which it may be appropriate in ovarian cancer based on the clinical course of the disease, and how we might exploit it to improve outcomes in ovarian cancer patients.

Expression and prognostic value of tumor stem cell markers ALDH1 and CD133 in colorectal carcinoma

The identification of cancer stem cells (CSCs) has improved the understanding of tumor occurrence and development. According to CSC theory, colorectal carcinoma (CRC) may be derived from these few cells. Thus, markers for CSCs may lead to the identification of CSCs and investigation of the correlation with various clinicopathological features and survival time in human CRC patients. Aldehyde dehydrogenase 1 (ALDH1) and CD133 (also known as Prominin-1 or AC133) were involved in the current study. The aim of the present study was to identify CSCs through markers of CSCs and to explore the value of the CSC markers, ALDH1 and CD133, in human CRC. The correlation between ALDH1 and CD133 protein expression and the various clinicopathological parameters were investigated through immunohistochemistry (IHC). In addition, the Kaplan-Meier method was used to estimate patients’ overall survival. Correlation of the survival differences between ALDH1- or CD133-positive expression and negative controls was analyzed by the log-rank test. Furthermore, the correlation between the expression of ALDH1 and CD133 was assessed by Spearman’s rank correlation. A marked correlation between the differentiation degree and expression of ALDH1 in tumor cells was demonstrated, but not with CD133 expression. In addition, it was demonstrated that low-stage tumors exhibit a higher expression of ALDH1 or CD133 staining compared with high-stage tumors. Meanwhile, CD133 expression was associated with lymph node metastasis-positive cases, but ALDH1 expression was not. Furthermore, compared with negative cases, ALDH1-positive patients exhibited a poor prognosis. However, no significant difference was identified between CD133-positive and -negative cases in terms of survival time. Overall, the results of the present study indicated that ALDH1 and CD133 may serve as useful markers of CSC to predict disease prognosis and clinicopathological characteristics of human CRC.

Inhibitory effect of Nodal on the expression of aldehyde dehydrogenase 1 in endometrioid adenocarcinoma of uterus

Cancers consist of heterogeneous populations. Recently, it has been demonstrated that cells with tumorigenic potential are limited to a small population, called cancer-initiating cells (CICs). Aldehyde dehydrogenase 1 (ALDH1) is one of the markers of CICs. We previously reported that ALDH1-high cases of uterine endometrioid adenocarcinoma showed poor prognosis, and ALDH1-high population of endometrioid adenocarcinoma cell line was more tumorigenic, resistant to anti-cancer drugs, and invasive than ALDH1-low population. Here, the regulatory signaling for ALDH1 was examined. The inhibition of TGF-β signaling increased ALDH1-high population. Among TGF-β family members, Nodal expression and ALDH1 expression levels were mutually exclusive. Immunohistochemical analysis on clinical samples revealed Nodal-high tumor cells to be ALDH-low and vise versa, suggesting that Nodal may inhibit ALDH1 expression via stimulating TGF-β signaling in uterine endometrioid adenocarcinoma. In fact, the addition of Nodal to endometrioid adenocarcinoma cell line reduced ALDH1-high population. Although ALDH1 mRNA level was not affected, the amount of ALDH1 protein appeared to be reduce by Nodal through ubiquitine-proteasome pathway. The regulation of TGF-β signaling might be a novel therapeutic target of CICs in endometrioid adenocarcinoma.

Novel prognostic markers for patients with triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a subtype of breast cancer characterized by poor prognosis. Currently, no reliable markers have been identified as having a predictive role for the prognosis of TNBC patients. In this study, 119 breast cancer samples, including 31 TNBC and 89 non-TNBC subtypes, were collected. The protein levels of cleaved caspase-3 (CC3), aldehyde dehydrogenase 1 (ALDH1), cyclooxygenase-2, Ki-67, H2A histone family member X, and phosphorylated protein kinase B protein were measured by immunohistochemical staining. The percentage of positive CC3 (P = .017), ALDH1 (P = .015), Ki-67 (P = .001), and H2A histone family member X (P = .016) staining was significantly higher in TNBC than in non-TNBC cases. Positive CC3 and ALDH1 staining significantly correlated with poor prognosis of breast cancer, the TNBC subtype and non-TNBC subtype. Positive cyclooxygenase-2 expression significantly correlated with the survival of patients with TNBC. Multivariate analysis demonstrated that CC3 and ALDH1 are independent prognostic factors for BC and non-TNBC. ALDH1 is a prognostic marker for TNBC patients.

Unraveling the complexity of hepatitis B virus: from molecular understanding to therapeutic strategy in 50 years

Hepatitis B virus (HBV) is a well-known hepadnavirus with a double-stranded circular DNA genome. Although HBV was first described approximately 50 years ago, the precise mechanisms of HBV infection and effective therapeutic strategies remain unclear. Here, we focus on summarizing the complicated mechanisms of HBV replication and infection, as well as genomic factors and epigenetic regulation. Additionally, we discuss in vivo models of HBV, as well as diagnosis, prevention and therapeutic drugs for HBV. Together, the data in this 50-year review may provide new clues to elucidate molecular mechanisms of HBV pathogenesis and shed new light on the future HBV therapies.

The expression of aldehyde dehydrogenase 1 in invasive primary breast tumors and axillary lymph node metastases is associated with poor clinical prognosis

The enzyme aldehyde dehydrogenase 1 (ALDH1) has been reported as a biomarker for identifying cancer stem cells. Previous studies have shown that ALDH1 expression in primary breast cancers was associated with poor clinical prognosis. In this study, we aimed to determine whether ALDH1 expression in axillary lymph node metastases (ALNM) of breast cancer patients was also associated with poor prognosis. Expression of ALDH1, ER, PgR, HER2 and KI-67 was examined in primary tumors and ALNM of 161 patients with invasive breast cancer. Survival analysis and multivariate analysis were used to determine the relationship between ALDH1 expression and clinical prognosis. Patients with positive ALDH1 expression in primary tumors and in ALNM had significantly shorter relapse-free survival (RFS) times and overall survival (OS) times compared to those whose tissues were ALDH1 negative. ALDH1-positivity in primary tumors was significant both in univariate and multivariate analyses of RFS and OS. ALDH1 expression in ALNM was significant in a univariate analysis of RFS and OS but not in a multivariate analysis of RFS and OS. We conclude that the expression of ALDH1 in primary breast tumors or ALNM may be one potential risk factor for poor, long-term outcomes.

EZH2 and ALDH1 expression in ductal carcinoma in situ: complex association with recurrence and progression to invasive breast cancer

The diagnosis of ductal carcinoma in situ (DCIS) is an increasingly common event due to widespread use of screening mammography. However, appropriate clinical management of DCIS is a major challenge in the absence of prognostic markers. Tumor-initiating cells may be particularly relevant for disease pathogenesis; therefore, two markers associated with such cells, EZH2 and ALDH1, were evaluated. A cohort of 248 DCIS patients was used to determine the association of EZH2 and ALDH1 with ipsilateral breast event, DCIS recurrence and progression to invasive breast cancer (IBC). In this cohort, high EZH2 expression was associated with the risk of an ipsilateral breast event and DCIS recurrence but not invasive progression. ALDH1 expression was observed in both the tumor and stromal compartment; however, in neither compartment were ALDH1 levels independently associated with evaluated study endpoints. Interestingly, the combination of high EZH2 with high epithelial ALDH1 was associated with disease progression. Therefore, ALDH1 within the DCIS lesion can add to the prognostic significance of EZH2, particularly in the context of risk of development of invasive disease.

Tissue-based identification of stem cells and epithelial-to-mesenchymal transition in breast cancer

Pathologists have recognized breast cancer heterogeneity for decades, but its causes were unknown. In recent years, basic science and translational studies have demonstrated that cancer stem cells contribute to the heterogeneous histologic and functional characteristics of breast cancer. Even more recently, the ability of breast epithelial cells to undergo an epithelial-to-mesenchymal transition has been linked to the acquisition of stem cells properties and enhanced tumor invasion, metastasis, and resistance to available treatments. The stem cells and cells undergoing epithelial-to-mesenchymal transition are attractive targets for therapy and breast cancer prevention. Despite current challenges, their identification in breast tissue samples would enable pathologists to discover and validate prognostic and predictive markers as well as identify markers of increased risk for breast cancer.