Immunohistochemical analysis of cancer stem cell markers in invasive breast carcinoma and associated ductal carcinoma in situ: relationships with markers of tumor hypoxia and microvascularity

A randomized controlled study of neoadjuvant metformin with chemotherapy in nondiabetic breast cancer women: The METNEO study

AIMS

Clinical data demonstrate that metformin exhibits antiproliferative, proapoptotic and antimetastatic actions. Here, correlative molecular studies were undertaken to determine the roles of transmembrane tumour necrosis factor-related apoptosis-inducing ligand death receptors (DRs) and CD133, a glycoprotein biomarker of breast cancer (BC) stem cells, in the advantageous action of metformin on pathological and clinical outcomes in BC patients on neoadjuvant chemotherapy.

METHODS

We randomly assigned 70 nondiabetic BC patients in a 1:1 ratio to either neoadjuvant AC-T chemotherapy (4 cycles of adriamycin 60 mg/m2 and cyclophosphamide 600 mg/m2, followed by 12 cycles of weekly paclitaxel 80 mg/m2) or AC-T with adjunct metformin (850 mg twice/day). The expressions of DR4, DR5 and CD133 were quantified in excised tissue samples with residual tumour cells.

RESULTS

The overall clinical response (odds ratio: 22.67 [2.77-185.18], P = .004), breast-conserving surgery (odds ratio: 3.67 [1.303-10.321], P = .014) and pathological complete response (β = 2.49 ± 1.13 [0.274-4.712], P = .028) rates were significantly improved in the metformin arm. Tissues obtained from the metformin arm had upregulated mRNA expression of DR4 (Mean delta cycle thresholds ± standard error of the mean: 2.68 ± 0.25 vs. 4.87 ± 0.53, P = .0003) and DR5 (0.21 ± 0.25 vs. 4.29 ± 0.95, P = .0004) compared to control arm. The enhanced DR expression negatively correlated with that of CD133 + BC stem cells, which was significantly reduced by metformin at both cytoplasmic/membranous (43.48 vs. 100.00%, P < .0001) and nuclear sites (4.35 vs. 95.00%, P < .0001).

CONCLUSION

Metformin improves clinical and pathological responses to neoadjuvant AC-T chemotherapy in BC via prompting directionally opposite changes in DRs (increments) and CD133 + (decrements) expressions. This study was registered in ClinicalTrials.gov (registration number: NCT04170465, https://clinicaltrials.gov/ct2/show/NCT04170465).

ALDH1+ tumor stem cells promote the progression of malignant fibrous tissue sarcoma by inhibiting SYNPO2 through hsa-mir-206

This research aims to explore the mechanism by which microRNAs may regulate the biological behavior of tumor cells in ALDH1+ fibrosarcoma. We identified differentially expressed miRNAs in ALDH + NMFH-1 cells, screened genes related to sarcoma metastasis in the TCGA database, and finally obtained key genes regulated by miRNAs that are involved in metastasis. The function and mechanism of these key genes were then validated at the cellular level. Using the ULCAN database, a significant correlation was found between hsa-mir-206 and mortality in sarcoma patients. WGCNA analysis identified 352 genes related to tumor metastasis. Through Venn diagrams, we obtained 15 metastasis-related genes regulated by hsa-mir-206. Survival analysis showed that SYNPO2 expression is significantly correlated with survival rate and is significantly underexpressed in multiple tumors. SYNPO2 showed a negative correlation with macrophages and a positive correlation with CD8+ T cells. After inhibiting the expression of hsa-mir-206 with siRNA plasmids, the mRNA expression of SYNPO2 was significantly upregulated. The results of CCK8 assay, scratch assay, and transwell assay showed that the proliferation and migration ability of NFMH-1 cells were promoted after SYNPO2 was inhibited. ALDH1+ tumor stem cells promote the proliferation and invasion of malignant fibrous histiocytoma cells by inhibiting SYNPO2 through hsa-mir-206.

The relationship between carbonic anhydrase IX (CAIX) and patient survival in breast cancer: systematic review and meta-analysis

PURPOSE

Hypoxia is a characteristic of many solid tumours and an adverse prognostic factor for cancer therapy. Hypoxia results in upregulation of carbonic anhydrase IX (CAIX) expression, a pH-regulating enzyme. Many human tissue studies have examined the prognostic value of CAIX expression in breast cancer but have yielded inconsistent results. Therefore, a systematic review and meta-analysis was undertaken to assess the prognostic value of CAIX expression for breast cancer patients.

METHODS

The electronic databases were systematically searched to identify relevant papers. The clinical outcomes included disease-free survival (DFS), recurrence-free survival (RFS) and overall survival (OS) in breast cancer patients. Review Manager version 5.4 was employed to analysis data from 23 eligible studies (containing 8390 patients).

RESULTS

High CAIX expression was associated with poorer RFS [HR = 1.42, 95% CI (1.32-1.51), p < 0.00001], DFS [HR = 1.64, 95% CI (1.34-2.00), p < 0.00001], and OS [HR = 1.48, 95% CI (1.22-1.80), p < 0.0001]. Heterogeneity was observed across the studies. There was an effect of the CAIX antibody employed, scoring methods, and tumour localisation on CAIX expression.

CONCLUSION

CAIX overexpression was significantly associated with poorer RFS, DFS, and OS in breast cancer patients. However, further work in high quantity tissue cohorts is required to define the optimal methodological approach.

Carbonic anhydrase IX-related tumoral hypoxia predicts worse prognosis in breast cancer: A systematic review and meta-analysis

Background

Tumoral hypoxia is associated with aggressiveness in many cancers including breast cancer. However, measuring hypoxia is complicated. Carbonic anhydrase IX (CAIX) is a reliable endogenous marker of hypoxia under the control of the master regulator hypoxia-inducible factor-1α (HIF-1α). The expression of CAIX is associated with poor prognosis in many solid malignancies; however, its role in breast cancer remains controversial.

Methods

The present study performed a meta-analysis to evaluate the correlation between CAIX expression and disease-free survival (DFS) and overall survival (OS) in breast cancer.

Results

A total of 2,120 publications from EMBASE, PubMed, Cochrane, and Scopus were screened. Of these 2,120 publications, 272 full texts were reviewed, and 27 articles were included in the meta-analysis. High CAIX was significantly associated with poor DFS (HR = 1.70, 95% CI = 1.39–2.07, p &lt; 0.00001) and OS (HR = 2.02, 95% CI 1.40–2.91, p = 0.0002) in patients with breast cancer. When stratified by subtype, the high CAIX group was clearly associated with shorter DFS (HR = 2.09, 95% CI =1.11–3.92, p = 0.02) and OS (HR = 2.50, 95% CI =1.53–4.07, p = 0.0002) in TNBC and shorter DFS in ER+ breast cancer (HR = 1.81 95% CI =1.38–2.36, p &lt; 0.0001).

Conclusion

High CAIX expression is a negative prognostic marker of breast cancer regardless of the subtypes.

CD133 is an independent predictive and prognostic marker in metastatic breast cancer

BACKGROUND

CD133 is a transmembrane glycoprotein and is considered the most common cell surface marker to identify cancer stem cells in hematological and solid tumors, including breast cancer.

OBJECTIVES

To evaluate the impact of immunohistochemical expression of CD133 on response rate and survival in metastatic breast cancer, as well as to correlate it with various demographics and clinicopathological characteristics.

METHODS

One-hundred metastatic breast cancer patients were prospectively recruited at the Medical Oncology Department at South Egypt Cancer Institute during the period from January 2018 to January 2020.

RESULTS

There was a statistically significant correlation between CD133 positive patients with various adverse clinicopathological parameters such as high grade (p= 0.013), higher tumor (p= 0.001), and nodal staging (p= 0.024) during a median follow-up time of 17 months. In addition, Cases with CD133 positive expression had a significantly lower survival time than those with negative expression (3-years OS 37.4% versus 85.5%, p= 0.024). Regarding the response rate, CD133 positive patients had a lower response rate than negative patients (50% versus 54%, p= 0.012).

CONCLUSIONS

Positive CD133 is correlated with poor prognosis in metastatic breast cancer patients.

Targeting carbonic anhydrase IX and XII isoforms with small molecule inhibitors and monoclonal antibodies

Carbonic anhydrases IX and CAXII (CAIX/CAXII) are transmembrane zinc metalloproteins that catalyze a very basic but crucial physiological reaction: the conversion of carbon dioxide into bicarbonate with a release of the proton. CA, especially CAIX and CAXII isoforms gained the attention of many researchers interested in anticancer drug design due to pivotal functions of enzymes in the cancer cell metastasis and response to hypoxia, and their expression restricted to malignant cells. This offers an opportunity to develop new targeted therapies with fewer side effects. Continuous efforts led to the discovery of a series of diverse compounds with the most abundant sulphonamide derivatives. Here we review current knowledge considering small molecule and antibody-based targeting of CAIX/CAXII in cancer.

Understanding metabolic alterations and heterogeneity in cancer progression through validated immunodetection of key molecular components: a case of carbonic anhydrase IX

Cancer metabolic heterogeneity develops in response to both intrinsic factors (mutations leading to activation of oncogenic pathways) and extrinsic factors (physiological and molecular signals from the extracellular milieu). Here we review causes and consequences of metabolic alterations in cancer cells with focus on hypoxia and acidosis, and with particular attention to carbonic anhydrase IX (CA IX). CA IX is a cancer-associated enzyme induced and activated by hypoxia in a broad range of tumor types, where it participates in pH regulation as well as in molecular mechanisms supporting cancer cells’ invasion and metastasis. CA IX catalyzes reversible conversion of carbon dioxide to bicarbonate ion plus proton and cooperates with a spectrum of molecules transporting ions or metabolites across the plasma membrane. Thereby CA IX contributes to extracellular acidosis as well as to buffering intracellular pH, which is essential for cell survival, metabolic performance, and proliferation of cancer cells. Since CA IX expression pattern reflects gradients of oxygen, pH, and other intratumoral factors, we use it as a paradigm to discuss an impact of antibody quality and research material on investigating metabolic reprogramming of tumor tissue. Based on the validation, we propose the most reliable CA IX-specific antibodies and suggest conditions for faithful immunohistochemical analysis of molecules contributing to heterogeneity in cancer progression.

CD133 mRNA-transfected dendritic cells induce coordinated cytotoxic and helper T cell responses against breast cancer stem cells

Breast cancer, a leading cause of death yearly, has been shown to be initiated and propagated by cancer stem cells. CD133, a cell surface antigen, has been shown to be present on cancer stem cells of many solid tumors, including breast cancer. A limitation to targeting CD133 is major histocompatibility complex (MHC)-restricted presentation of epitopes, leading to activation of only one arm of the immune system: either CD4+ helper T cells or CD8+ cytotoxic T cells. Thus, we hypothesized that by creating an MHC-independent vaccination, we would give rise to a sustained immune response against CD133 in triple-negative breast cancer (TNBCs). We transfected CD133 mRNA into dendritic cells and then tested this in animal models of TNBC. We showed in these models the activation of both CD8+ cytotoxic T cells and CD4+ helper T cells by dendritic cell vaccination with modified CD133 mRNA, with subsequent decrease in tumor growth. This study for the first time demonstrates in a syngeneic mouse model of TNBC that targeting CD133, in an MHC-independent manner, is an effective strategy against the cancer stem cell population, leading to tumor abrogation.

A review of the racial heterogeneity of breast cancer stem cells

Breast Cancer Stem Cells has become the toast of many breast cancer investigators in the past two decades owing to their crucial roles in tumourigenesis, progression, differentiation, survival and chemoresistance. Despite the growing list of research data in this field, racial or ethnic comparison studies on these stem cells remain scanty. This study is a comparative racial analysis of putative breast cancer stem cells. Research articles on the clinicopathological significance of breast cancer stem cells within a period of 17 years (2003-2020) were reviewed across 5 major races (African/Black American, Asian, Caucasian/White, Hispanic/Latino, and American). The associations between the stem cells markers (CD44+/CD24^-/low, BMI1, ALDH1, CD133, and GD2) and clinicopathological and clinical outcomes were analysed. A total of 40 studies were included in this study with 50% Asian, 25% Caucasian, 10% African, 5% American and 2.5% Hispanic/Latino, and 7.5% other mixed races. CD44⁺/CD24^-/low has been associated with TNBC/Basal like phenotype across all races. It is generally associated with poor clinicopathological features such as age, tumour size, lymph node metastasis and lymphovascular invasion. In Asians, CD44⁺/CD24^-/low was associated with DFS and OS but not in Caucasians. ALDH1 was the most studied breast CSC marker (40% of all studies on breast cancer stem cell markers) also associated with poor clinicopathological features including size, age, stage, lymph node metastasis and Nottingham Prognostic Index. ALDH1 was also associated with DFS and OS in Asians but not Caucasians. Racial variations exist in breast cancer stem cell pattern and functions but ill-defined due to multiple factors. Further research is required to better understand the role of breast CSC.

The role of ALDH1A1 in contributing to breast tumour aggressiveness: A study conducted in an African population

Aldehyde dehydrogenase 1 member A1 (ALDH1A1) is one of the most well studied breast cancer stem cells. Its expression has been associated with poor clinicopathological features and clinical outcomes in several studies. This paper studies the expression of ALDH1A1 and its combination with CD44+/CD24-/low breast cancer stem cell and their association with clinicopathological parameters and molecular subtypes.

METHOD

Tissue Microarray was constructed from 222 Formalin Fixed Paraffin Embedded (FFPE) breast cancer tissues. The expression of ALDH1A1, CD44 and CD24 were assessed by Immunohistochemistry (IHC). The association of ALDH1A1 and its association with clinicopathological parameters, molecular subtypes, CD44 and CD24 were studied in an African population. The association between CD44+/CD24-/low/ALDH1+ and the clinicopathological phenotypes were also studied.

RESULTS

A high ALDH1A1 expression of 90% was recorded in this study. No association was found between ALDH1A1 and clinicopathological parameters. ALDH1A1 was positively associated with CD24 (r = 0.228, OR-4.599 95% CI- 1.751-12.076, p = 0.001) and CD44 (r = 0.228, OR-5.538 95%CI- 1.841-16.662, p = 0.001) but not associated with CD44+/CD24-/low (r = 0.134, OR- 2.720 95%CI- 0.959-7.710, p = 0.052). CD44+/CD24-/ALDH1+ however had significant associations with Age (p- 0.020, r = 0.161, OR- 2.771, 95%CI 1.147-6.697), Gender (p = 0.004, OR- 15.333 95%CI 1.339-175.54), Tumour grade (p = 0.005, r = 0.197, OR-3.913 95%CI 1.421-10.776) and clinical prognostic staging (p = 0.014, r = 0.182, OR-3.028 95%CI- 1.217-7.536). There was no association between CD44+/CD24-/ALDH1+ and the molecular subtypes.

CONCLUSION

The high expression of ALDH1A1 in breast cancer makes it an important target for targeted therapy. This study further confirms the increased tumourigenicity of CD44+/CD24-/ALDH1+ combination phenotype and its association with increased tumour grade and clinical prognostic stage. Survival studies of ALDH1A1 and other breast cancer stem cells in African populations are strongly recommended to help further understand their effect on tumour aggressiveness.

Expression of CD 133 in Invasive Ductal Carcinoma of Breast

Background:

CD133 is a commonly used cancer stem cell (CSC) marker in breast cancer. However, the association between CD133 expression, with clinicopathological features and prognosis in breast cancer, is poorly understood in the Indian subcontinent. This study was designed to explore the expression of CD 133 in breast carcinoma and to know its association between CD133 and clinicopathological characteristics.

Methods:

A total of fifty seven cases were included in the study. All the clinicopathological parameters were collected from Department of Pathology archives. Slides, blocks, clinical information, tumor size and axillary lymph node status were obtained from medical records and the pathology reports. Immunohistochemistry was done using CD 133 antibodies. Both Cytoplasmic and membranous staining was taken a positive. Scoring was done based on percentage of positive cells and intensity of staining. MS Excel, SPSS version 22 (IBM SPSS Statistics, Somers NY, USA) was used to analyze data.p value < 0.05 was considered as statistically significant.

Results:

Statistically significant association between the CD 133 expression and nodal metastasis, tumor stage and Nottingham prognostic index was analysed. There was no statistical correlation between CD 133 expression age, tumor grade and tumor size. The disease free survival showed the mean disease free survival of CD 133 positivity cases was 16months. And the patients who were negative for CD 133 expression had mean survival of 30 months. By the Kaplan Mayer graph it was evident that the more the CD 133 expression the lesser was the disease free survival of the patients.

Conclusion:

CD 133 expression was seen in 77.08% cases and was associated with tumor stage, lymph node metastasis, poor Nottingham prognostic index and worse disease free survival. An increasing trend of association was seen between CD 133 expression and Age, Tumor Size and Tumor grade.

The Role of Breast Cancer Stem Cell-Related Biomarkers as Prognostic Factors

Breast cancer is one of the leading causes of cancer-related deaths in women worldwide, and its incidence is on the rise. A small fraction of cancer stem cells was identified within the tumour bulk, which are regarded as cancer-initiating cells, possess self-renewal and propagation potential, and a key driver for tumour heterogeneity and disease progression. Cancer heterogeneity reduces the overall efficacy of chemotherapy and contributes to treatment failure and relapse. The cell-surface and subcellular biomarkers related to breast cancer stem cell (BCSC) phenotypes are increasingly being recognised. These biomarkers are useful for the isolation of BCSCs and can serve as potential therapeutic targets and prognostic tools to monitor treatment responses. Recently, the role of noncoding microRNAs (miRNAs) has extensively been explored as novel biomarker molecules for breast cancer diagnosis and prognosis with high specificity and sensitivity. An in-depth understanding of the biological roles of miRNA in breast carcinogenesis provides insights into the pathways of cancer development and its utility for disease prognostication. This review gives an overview of stem cells, highlights the biomarkers expressed in BCSCs and describes their potential role as prognostic indicators.

Development and verification of a personalized immune prognostic feature in breast cancer

IMPACT STATEMENT

Breast cancer is among the highest prevalent malignant tumors worldwide with a low survival ratio. Immune-related genes have great potential as prognostic indicator in many types of tumors. Therefore, we have attempted to develop immune-related gene markers to enhance the prognosis of breast cancer. 17-IRGPs signature was constructed as a newly developed prognostic indicator to predict the survival of BC patients.

CAIX forms a transport metabolon with monocarboxylate transporters in human breast cancer cells

Tumor cells rely on glycolysis to meet their elevated demand for energy. Thereby they produce significant amounts of lactate and protons, which are exported via monocarboxylate transporters (MCTs), supporting the formation of an acidic microenvironment. The present study demonstrates that carbonic anhydrase IX (CAIX), one of the major acid/base regulators in cancer cells, forms a protein complex with MCT1 and MCT4 in tissue samples from human breast cancer patients, but not healthy breast tissue. Formation of this transport metabolon requires binding of CAIX to the Ig1 domain of the MCT1/4 chaperon CD147 and is required for CAIX-mediated facilitation of MCT1/4 activity. Application of an antibody, directed against the CD147-Ig1 domain, displaces CAIX from the transporter and suppresses CAIX-mediated facilitation of proton-coupled lactate transport. In cancer cells, this "metabolon disruption" results in a decrease in lactate transport, reduced glycolysis, and ultimately reduced cell proliferation. Taken together, the study shows that carbonic anhydrases form transport metabolons with acid/base transporters in human tumor tissue and that these interactions can be exploited to interfere with tumor metabolism and proliferation.

CD133 in Breast Cancer Cells: More than a Stem Cell Marker

Initially correlated with hematopoietic precursors, the surface expression of CD133 was also found in epithelial and nonepithelial cells from adult tissues in which it has been associated with a number of biological events. CD133 is expressed in solid tumors as well, including breast cancer, in which most of the studies have been focused on its use as a surface marker for the detection of cells with stem-like properties (i.e., cancer stem cells (CSCs)). Differently with other solid tumors, very limited and in part controversial are the information about the significance of CD133 in breast cancer, the most common malignancy among women in industrialized countries. In this review, we summarize the latest findings about the implication of CD133 in breast tumors, highlighting its role in tumor cells with a triple negative phenotype in which it directly regulates the expression of proteins involved in metastasis and drug resistance. We provide updates about the prognostic role of CD133, underlining its value as an indicator of increased malignancy of both noninvasive and invasive breast tumor cells. The molecular mechanisms at the basis of the regulation of CD133 levels in breast tumors have also been reviewed, highlighting experimental strategies capable to restrain its level that could be taken into account to reduce malignancy and/or to prevent the progression of breast tumors.

Increased Expression of the Matrix-Modifying Enzyme Lysyl Oxidase-Like 2 in Aggressive Hepatocellular Carcinoma with Poor Prognosis

Background/Aims

Lysyl oxidase-like 2 (LOXL2), a collagen-modifying enzyme, has been implicated in cancer invasiveness and metastasis.

Methods

We evaluated the expression of LOXL2 protein, in addition to carbonic anhydrase IX (CAIX), keratin 19, epithelial cell adhesion molecule, and interleukin 6, in 105 resected hepatocellular carcinomas (HCCs) by immunohistochemistry.

Results

LOXL2 positivity was found in 14.3% (15/105) of HCCs, and it was significantly associated with high serum α-fetoprotein levels, poor differentiation, fibrous stroma, portal vein invasion, and advanced TNM stage (p＜0.05 for all). Additionally, LOXL2 positivity was significantly associated with CAIX (p=0.005) and stromal interleukin 6 expression (p=0.001). Survival analysis of 99 HCC patients revealed LOXL2 positivity to be a poor prognostic factor; its prognostic impact appeared in progressed HCCs. Furthermore, LOXL2 positivity was shown to be an independent predictor of overall survival and disease-specific survival (p＜0.05 for all). Interestingly, co-expression of LOXL2 and CAIX was also an independent predictor for overall survival, disease-specific survival, disease-free survival, and extrahepatic recurrence-free survival (p＜0.05 for all).

Conclusions

LOXL2 expression represents a subgroup of HCCs with more aggressive behavior and is suggested to be a poor prognostic marker in HCC patients.

MNK1/NODAL Signaling Promotes Invasive Progression of Breast Ductal Carcinoma In Situ

The mechanisms by which breast cancers progress from relatively indolent ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC) are not well understood. However, this process is critical to the acquisition of metastatic potential. MAPK-interacting serine/threonine-protein kinase 1 (MNK1) signaling can promote cell invasion. NODAL, a morphogen essential for embryogenic patterning, is often reexpressed in breast cancer. Here we describe a MNK1/NODAL signaling axis that promotes DCIS progression to IDC. We generated MNK1 knockout (KO) or constitutively active MNK1 (caMNK1)-expressing human MCF-10A-derived DCIS cell lines, which were orthotopically injected into the mammary glands of mice. Loss of MNK1 repressed NODAL expression, inhibited DCIS to IDC conversion, and decreased tumor relapse and metastasis. Conversely, caMNK1 induced NODAL expression and promoted IDC. The MNK1/NODAL axis promoted cancer stem cell properties and invasion in vitro. The MNK1/2 inhibitor SEL201 blocked DCIS progression to invasive disease in vivo. In clinical samples, IDC and DCIS with microinvasion expressed higher levels of phospho-MNK1 and NODAL versus low-grade (invasion-free) DCIS. Cumulatively, our data support further development of MNK1 inhibitors as therapeutics for preventing invasive disease. SIGNIFICANCE: These findings provide new mechanistic insight into progression of ductal carcinoma and support clinical application of MNK1 inhibitors to delay progression of indolent ductal carcinoma in situ to invasive ductal carcinoma.

Knockdown of USF1 Inhibits the Vasculogenic Mimicry of Glioma Cells via Stimulating SNHG16/miR-212-3p and linc00667/miR-429 Axis

The anti-angiogenic treatment of malignant glioma cells is an effective method to treat high-grade gliomas. However, due to the presence of vasculogenic mimicry (VM), the anti-angiogenic treatment of gliomas is not significantly effective in improving overall patient median survival. Therefore, this study investigated the mechanism of mimic formation of angiogenesis in gliomas. The results of this experiment indicate that the expression of upstream transcription factor 1 (USF1) is upregulated in glioma tissues and cells. USF1 knockdown inhibits the proliferation, migration, invasion, VM, and expression of VM-associated proteins in glioma cells by stimulating SNHG16 and linc00667. These two long non-coding RNAs (lncRNAs) regulate ALHD1A1 through the competing endogenous RNA (ceRNA) mechanism influencing the VM of glioma. This study is the first to demonstrate that the USF1/SNHG16/miR-212-3p/ALDH1A1 (aldehyde dehydrogenase-1) and USF1/linc00667/miR-429/ALDH1A1 axis regulates the VM of glioma cells, and these findings might provide a novel strategy for glioma treatment.

Site- and structure-specific characterization ofN-glycoprotein markers of MCF-7 cancer stem cells using isotopic-labelling quantitativeN-glycoproteomics

High-throughput proteome-level characterization of stemness markers of MCF-7 cancer stem cells was carried out using our recently developed site- and structure-specific isotopic-labelled quantitativeN-glycoproteomics pipeline.

Protective role of all-trans retinoic acid (ATRA) against hypoxia-induced malignant potential of non-invasive breast tumor derived cells

Background

The presence of hypoxic areas is common in all breast lesions but no data clearly correlate low oxygenation with the acquisition of malignant features by non-invasive cells, particularly by cells from ductal carcinoma in situ (DCIS), the most frequently diagnosed tumor in women.

Methods

By using a DCIS-derived cell line, we evaluated the effects of low oxygen availability on malignant features of non-invasive breast tumor cells and the possible role of all-trans retinoic acid (ATRA), a well-known anti-leukemic drug, in counteracting the effects of hypoxia. The involvement of the β2 isoform of PI-PLC (PLC-β2), an ATRA target in myeloid leukemia cells, was also investigated by specific modulation of the protein expression.

Results

We demonstrated that moderate hypoxia is sufficient to induce, in DCIS-derived cells, motility, epithelial-to-mesenchymal transition (EMT) and expression of the stem cell marker CD133, indicative of their increased malignant potential.

Administration of ATRA supports the epithelial-like phenotype of DCIS-derived cells cultured under hypoxia and keeps down the number of CD133 positive cells, abrogating almost completely the effects of poor oxygenation. We also found that the mechanisms triggered by ATRA in non-invasive breast tumor cells cultured under hypoxia is in part mediated by PLC-β2, responsible to counteract the effects of low oxygen availability on CD133 levels.

Conclusions

Overall, we assigned to hypoxia a role in increasing the malignant potential of DCIS-derived cells and we identified in ATRA, currently used in treatment of acute promyelocytic leukemia (APL), an agonist potentially useful in preventing malignant progression of non-invasive breast lesions showing hypoxic areas.

Potential protective effect of ALDH-1 stromal expression against early recurrence of operable breast cancers

Background

The emerging cancer stem cell (CSC) model proposes that the stem cell niche plays a major role in the risk of cancer recurrence. Enzymatic activity of aldehydes, including aldehyde dehydrogenase 1 (ALDH-1), has been used as a marker of normal and malignant breast stem cells (BSCs). However, the clinical implications of the expression of stem cell markers in the stroma have not yet been investigated.

Methods

To determine the relationships of ALDH-1 expression, the currently reliable BSCs marker, with clinical characteristics and survival, we used immunohistochemical staining of tissue microarrays from 180 stroma and epithelial cancer tissues in patients diagnosed with operable early breast cancer (stage 0-III).

Results

ALDH-1 expression was observed in 93.4% of the stromal cells and in 37.2% of the epithelial cells, and the expression levels between the two cell types were significantly correlated (P=0.001). The stromal expression of ALDH-1 was not correlated with any clinical factors, whereas epithelial expression was significantly correlated with a negative estrogen-receptor status (P<0.001), high proliferation based on Ki-67 expression (P<0.001), and younger age (P=0.04). After 27.8 months of follow up, negative stromal expression of ALDH-1 was significantly correlated with shorter overall survival (positive, 56.9±3.0 months vs. negative, 30.5±3.0 months; P=0.01).

Conclusions

Stromal ALDH-1 expression was not directly correlated with known clinical factors, but its expression may play a protective role against early recurrence. Further observation and large-scale studies are needed to validate the clinical implications of ALDH-1 in breast cancer.

pH regulators to target the tumor immune microenvironment in human hepatocellular carcinoma

Interfering with tumor metabolism is an emerging strategy for treating cancers that are resistant to standard therapies. Featuring a rapid proliferation rate and exacerbated glycolysis, hepatocellular carcinoma (HCC) creates a highly hypoxic microenvironment with excessive production of lactic and carbonic acids. These metabolic conditions promote disease aggressiveness and cancer-related immunosuppression. The pH regulatory molecules work as a bridge between tumor cells and their surrounding milieu. Herein, we show that the pH regulatory molecules CAIX, CAXII and V-ATPase are overexpressed in the HCC microenvironment and that interfering with their pathways exerts antitumor activity. Importantly, the V-ATPase complex was expressed by M2-like tumor-associated macrophages. Blocking ex vivo V-ATPase activity established a less immune-suppressive tumor microenvironment and reversed the mesenchymal features of HCC. Thus, targeting the unique cross-talk between tumor cells and the tumor microenvironment played by pH regulatory molecules holds promise as a strategy to control HCC progression and to reduce the immunosuppressive pressure mediated by the hypoxic/acidic metabolism, particularly considering the potential combination of this strategy with emerging immune checkpoint-based immunotherapies.

Carbonic Anhydrase IX (CAIX), Cancer, and Radiation Responsiveness

Carbonic anhydrase IX has been under intensive investigation as a therapeutic target in cancer. Studies demonstrate that this enzyme has a key role in pH regulation in cancer cells, allowing these cells to adapt to the adverse conditions of the tumour microenviroment. Novel CAIX inhibitors have shown efficacy in both in vitro and in vivo pre-clinical cancer models, adversely affecting cell viability, tumour formation, migration, invasion, and metastatic growth when used alone. In co-treatments, CAIX inhibitors may enhance the effects of anti-angiogenic drugs or chemotherapy agents. Research suggests that these inhibitors may also increase the response of tumours to radiotherapy. Although many of the anti-tumour effects of CAIX inhibition may be dependent on its role in pH regulation, recent work has shown that CAIX interacts with several of the signalling pathways involved in the cellular response to radiation, suggesting that pH-independent mechanisms may also be an important basis of its role in tumour progression. Here, we discuss these pH-independent interactions in the context of the ability of CAIX to modulate the responsiveness of cancer to radiation.

Aldehyde dehydrogenase 1 expression is correlated with poor prognosis in breast cancer

Breast cancer (BC) is one of the most common cancers worldwide, and is a major cause of death in women. Aldehyde dehydrogenase 1 (ALDH1) is a marker of stem cells and cancer stem cells, and its activity correlates with the outcome of various tumors, including BC. This study aimed to analyze the relationship between ALDH1 expression and clinicopathological characters in BC and the prognostic significance of ALDH1.We used quantitative reverse-transcription PCR (qRT-PCR) to detect ALDHA1 mRNA levels in 25 fresh frozen BC samples and matched noncancerous samples. Immunohistochemistry on tissue microarrays was used to analyze protein expression in 137 paraffin-embedded BC tissues and corresponding noncancerous tissues. STATA 16.0 software was used for statistical analysis.The results suggested that levels of both ALDH1 mRNA and protein in BC were significantly higher than in corresponding adjacent breast samples (3.856 ± 0.3442 vs 1.385 ± 0.1534, P < .001; 52.6% vs 25.5%, P < .001, respectively). ALDH1 protein expression was also significantly associated with histological grade (P  =  .017), tumor size (P  =  .017), and tumor-node-metastasis (TNM) stage (P  =  .038). Multivariate analysis using the Cox regression model demonstrated that ALDH1 expression (P  =  .024), molecular typing (P  =  .046), and TNM classification (P  =  .034) were independent predictive factors for the outcome of BC. Kaplan-Meier analysis and the log-rank test indicated that patients with high ALDH1 expression, triple-negative BC, and advanced TNM stage had a reduced overall survival time.These data suggest that ALDH1 could be used as a prognostic factor for BC and may provide a useful therapeutic target in the treatment of BC.

Prognostic value of putative cancer stem cell markers (CD24, CD44, CD133, and ALDH1) in human papillary thyroid carcinoma

We hypothesized that cancer stem cells (CSCs) are responsible for the poor outcome and aggressive clinicopathological factors. We surveyed the expression of selected CSC markers that are specifically expressed in thyroid papillary carcinoma (PTC). A total of 80 patients with PTC from 2011 to 2012 were enrolled. We selected CD24, CD44, CD133, and dehydrogenase 1 (ALDH1), as they have been suggested to be candidate CSC markers. Expression of these markers was investigated by immunohistochemical (IHC) staining. IHC staining for CD24, CD44, CD133 and ALDH1 was evaluated according to staining intensity and proportion. The intensity and proportion scores were multiplied together for a total score, which was either 0-2 (negative) or 3-7 (positive). IHC for CD133 in PTC was positive in 49 (61.3%) patients, and CD24 was positive in 28 (35.0%). Seventy-eight (97.5%) patients were CD44 positive and 79 (98.8%) were ALDH1 positive. When we assessed the relationship between CSC markers and clinicopathological factors in PTC, CD24 expression was inversely correlated with multifocality (p=0.045; odds ratio [OR], 0.370; 95% confidence interval [CI], 0.138-0.991) and CD44 expression was significantly correlated with a BRAF mutation (p=0.001; OR, 7.091; 95% CI, 4.101-12.262). However, CD133 and ALDH1 were not associated with any of the clinicopathological parameters. CD24 expression was inversely correlated with multifocality, and CD44 expression was significantly correlated with a BRAF mutation. Therefore, CD24 and CD44 are related to clinicopathological aggressive features and important for determining surgical extent in patients with PTC.

Clinicopathological characteristics and prognostic value of cancer stem cell marker CD133 in breast cancer: a meta-analysis

Background

The association of CD133 overexpression with clinicopathological significance and prognosis in patients with breast cancer remains controversial. We thus performed a meta-analysis to evaluate the role of CD133 expression in the development and prognosis of breast cancer.

Methods

The databases PubMed, Embase, and Cochrane Library (updated to August 1, 2016) were searched. Pooled odds ratios (ORs) or hazard ratios (HRs) with 95% confidence intervals (95% CI) were used to evaluate the impact of CD133 expression on clinicopathological features, overall survival, and disease-free survival.

Results

A total of 1,734 patients from 13 studies were subject to final analysis. The results showed a significant association between overexpression of CD133 and estrogen receptor status (OR 0.35, 95% CI 0.18–0.70), progesterone receptor status (OR 0.56, 95% CI 0.43–0.74), human epidermal growth factor-2 status (OR 1.81, 95% CI 1.33–2.45), lymph node metastasis (OR 1.98, 95% CI 1.34–2.92), and tumor histological grade (OR 1.79, 95% CI 1.26–2.54) in breast cancer. However, no significant correlation was found between upregulation of CD133 expression and onset age (OR 1.03, 95% CI 0.70–1.53) or tumor size (OR 1.29, 95% CI 0.80–2.09). Moreover, CD133-positive breast cancer patients had a higher risk of mortality (HR 1.91, 95% CI 1.21–3.03) and disease progression (HR 2.70, 95% CI 1.05–6.95).

Conclusion

This meta-analysis suggested that CD133 might be a predictor of clinical outcomes as well as prognosis and could be a potentially new gene therapy target for breast cancer patients.

Evaluation of Breast Cancer Stem Cells and Intratumor Stemness Heterogeneity in Triple-negative Breast Cancer as Prognostic Factors

Triple-negative breast cancer (TNBC) is a tumor subtype with aggressive behavior and poor clinical outcome for lacking effective therapies. Breast cancer stem cells (BCSCs) have been suggested to have tumor-initiating properties, but it remains unclear whether their presence contributes to the increased aggressiveness and poor prognosis of TNBC. Also, the breast cancers display frequent inter- and intra-tumor heterogeneity, which adds the complexity in diagnosis and predicting prognosis. Here we investigated the clinical relevance and prognostic value of the BCSC markers, CD44⁺/CD24^-, aldehyde dehydrogenase family 1 member A1 (ALDH1A1) and CD133 in 88 TNBC cases. We found that a few patients displayed spatial heterogeneity of the BCSC markers in expression, which was defined as intratumor stemness heterogeneity (ITSH) below. There was no significant correlation between any BCSC marker alone or ITSH and progression-free survival (PFS). Interestingly, the combined BCSC phenotype by CD44⁺/CD24^- and ALDH1A1 was significantly associated with worse PFS (P = 0.009). Further stratification analysis revealed that this combined BCSC phenotype was an independent prognostic factor for PFS in some subgroups. In conclusion, we demonstrated the existence of ITSH in TNBC and found that the ITSH as well as a single BCSC marker was not significantly associated with survival, whereas combing the analysis of BCSC markers could improve prognostic value. Our findings may lead to an improvement of prognostic indicators in TNBC.

Biomarker discovery to improve prediction of breast cancer survival: using gene expression profiling, meta-analysis, and tissue validation

Purpose

Breast cancer is the leading cause of cancer death worldwide in women. The molecular mechanism for human breast cancer is unknown. Gene microarray has been widely used in breast cancer research to identify clinically relevant molecular subtypes as well as to predict prognosis survival. So far, the valuable multigene signatures in clinical practice are unclear, and the biological importance of individual genes is difficult to detect, as the described signatures virtually do not overlap. Early prognosis of this disease, breast invasive ductal carcinoma (IDC) and breast ductal carcinoma in situ (DCIS), is vital in breast surgery.

Methods

Thus, this study reports gene expression profiling in large breast cancer cohorts from Gene Expression Omnibus, including GSE29044 (N=138) and GSE10780 (N=185) test series and four independent validation series GSE21653 (N=266), GSE20685 (N=327), GSE26971 (N=276), and GSE12776 (N=204). Significantly differentially expressed genes in human breast IDC and breast DCIS were detected by transcriptome microarray analysis.

Results

We created a set of three genes (MAMDC2, TSHZ2, and CLDN11) that were significantly correlated with disease-free survival of breast cancer patients using a univariate Cox regression model (significance level P<0.01) in a meta-analysis. Based on the risk score of the three genes, the test series patients could be separated into low-risk and high-risk groups with significantly different survival times. This signature was validated in the other three cohorts. The prognostic value of this three-gene signature was confirmed in the internal validation series and another four independent breast cancer data sets. The prognostic impact of one of the three genes, CLDN11, was confirmed by immunohistochemistry. CLDN11 was significantly overexpressed in human breast IDC as compared with normal breast tissues and breast DCIS.

Conclusion

Using novel gene expression profiling together with a meta-analysis validation approach, we have identified a three-gene signature with independent prognostic impact. Furthermore, CLDN11 may offer a biomarker to predict prognosis as well as a new target for prognostic and therapeutic intervention for human breast IDC.

Different Biological Action of Oleic Acid in ALDHhigh and ALDHlow Subpopulations Separated from Ductal Carcinoma In Situ of Breast Cancer

The mechanisms underlying breast cancer progression of ductal carcinoma in situ (DCIS) associated with fatty acids are largely unknown. In the present study, we compared the action of oleic acid (OA) on two human DCIS cell lines, MCF10DCIS.COM (ER/PR/HER2-negative) and SUM225 (HER2 overexpressed). OA led to a significant increase in proliferation, migration, lipid accumulation and the expression of lipogenic proteins, such as SREBP-1, FAS and ACC-1, in MCF10DCIS.COM cells but not SUM225 cells. The ALDH^high subpopulation analyzed by the ALDEFLUOR assay was approximately 39.2±5.3% of MCF10DCIS.COM cells but was small (3.11±0.9%) in SUM225 cells. We further investigated the different biological action of OA in the distinct ALDH^low and ALDH^high subpopulations of MCF10DCIS.COM cells. OA led to an increase in the expression of ALDH1A1, ALDH1A2 and ALDH1A3 in MCF10DCIS.COM cells. SREBP-1 and ACC-1 were highly expressed in ALDH^high cells relative to ALDH^low cells, whereas FAS was higher in ALDH^low cells. In the presence of OA, ALDH^high cells were more likely to proliferate and migrate and displayed significantly high levels of SREBP-1 and FAS and strong phosphorylation of FAK and AKT relative to ALDH^low cells. This study suggests that OA could be a critical risk factor to promote the proliferation and migration of ALDH^high cells in DCIS, leading to breast cancer progression.

Poor outcome of hepatocellular carcinoma with stemness marker under hypoxia: resistance to transarterial chemoembolization

Hypoxia is known to be important in the generation and maintenance of stemness; however, its clinical significance is yet to be determined in human hepatocellular carcinoma. The expression of stemness (K19, EpCAM) and hypoxia (carbonic anhydrase-IX (CAIX))-related markers were investigated by immunohistochemistry in three hepatocellular carcinoma cohorts. The clinicopathologic features, response to transarterial chemoembolization, and outcomes were compared. In cohort 1 (n=14, biopsy-transarterial chemoembolization-resection-matched hepatocellular carcinoma), all K19-, EpCAM-, or CAIX-positive hepatocellular carcinomas on initial biopsy (6/6, 100%) showed residual tumors after transarterial chemoembolization, whereas 75% (6/8) of all-negative hepatocellular carcinomas on biopsy showed complete necrosis in the post-transarterial chemoembolization-resected specimens. In cohort 2 (n=85, explanted hepatocellular carcinomas with/without transarterial chemoembolization; totally necrotic hepatocellular carcinoma after transarterial chemoembolization was not included), the expression of K19, EpCAM, and CAIX, and their coexpression, was more frequently observed with a greater number of transarterial chemoembolization sessions, and the expression of these markers was also correlated to each other. CAIX expression was shown to be an independent factor for recurrence and survival, and combination of CAIX with Milan criteria significantly increased the time-dependent integrative area under the curve values for recurrence and survival. In cohort 3 (n=339, resected hepatocellular carcinomas without transarterial chemoembolization), CAIX(+) hepatocellular carcinomas exhibited higher K19 and EpCAM expression, and more invasive pathological features. CAIX expression and TNM stage were independent predictors of extrahepatic recurrence, and the addition of CAIX to the TNM stage significantly increased time-dependent integrative area under the curve values. In conclusion, the expression of stemness (K19, EpCAM) and hypoxia (CAIX)-related markers were correlated each other, and hepatocellular carcinoma expressing these markers showed resistance to transarterial chemoembolization and poorer outcome. Evaluation for both markers of stemness and hypoxia may have an additional value in predicting hepatocellular carcinoma outcome, especially for transarterial chemoembolization-treated hepatocellular carcinomas.

The Ribonucleic Complex HuR-MALAT1 Represses CD133 Expression and Suppresses Epithelial-Mesenchymal Transition in Breast Cancer

Epithelial-to-mesenchymal transition (EMT) is a core process underlying cell movement during embryonic development and morphogenesis. Cancer cells hijack this developmental program to execute a multi-step cascade, leading to tumorigenesis and metastasis. CD133 (PROM1), a marker of cancer stem cells, has been shown to facilitate EMT in various cancers, but the regulatory networks controlling CD133 gene expression and function in cancer remain incompletely delineated. In this study, we show that a ribonucleoprotein complex including the long noncoding RNA MALAT1 and the RNA-binding protein HuR (ELAVL1) binds the CD133 promoter region to regulate its expression. In luminal nonmetastatic MCF-7 breast cancer cells, HuR silencing was sufficient to upregulate N-cadherin (CDH2) and CD133 along with a migratory and mesenchymal-like phenotype. Furthermore, we found that in the basal-like metastatic cell line MDA-MB-231 and primary triple-negative breast cancer tumor cells, the repressor complex was absent from the CD133-regulatory region, but was present in the MCF-7 and primary ER+ tumor cells. The absence of the complex from basal-like cells was attributed to diminished expression of MALAT1, which, when overexpressed, dampened CD133 levels. In conclusion, our findings suggest that the failure of a repressive complex to form or stabilize in breast cancer promotes CD133 upregulation and an EMT-like program, providing new mechanistic insights underlying the control of prometastatic processes. Cancer Res; 76(9); 2626-36. ©2016 AACR.

CD44 positive/CD24 negative (stem cell like property) breast carcinoma cells as marker of tumor aggression

BACKGROUND

Cells with stem cell like properties in solid organ malignancies like breast and pancreas have been studied over the last decade and have been found to be associated with poor prognosis. Presence of CD44 positive and CD24 negative tumor cells in breast carcinoma (cells with 'stem cell' like property) as marker of aggressiveness and poor prognosis was checked for association with various markers of disease aggression like age at presentation, size of tumor, histological grade of tumor, triple negative status, level of micro-vessel density, and nodal status.

METHODS

Single and double staining immunohistochemistry protocol was used for CD24 and CD44 staining. The staining protocol was repeated with more contemporary techniques using fluorescent chromogen also.

RESULTS

52 cases, all females who underwent modified radical mastectomy at a tertiary care hospital over a period of 3 years, were evaluated. No association was found between presence of stem cells and size of lesion, histological grade, triple negative status or micro-vessel density. However, significant association was found with respect to younger age of presentation (p value = 0.044). 20 out of 25 cases with nodal metastasis were positive for presence of stem cells (p value is 0.0003). Further, 18 of these 20 cases also had stem cells in the metastatic nodule. Fluorescent chromogens (FITC and Cyanine Red) revealed similar results.

CONCLUSION

Cases positive for stem cells showed earlier onset of disease and proneness to nodal metastasis.

Breast cancer stem-like cells: clinical implications and therapeutic strategies

Breast cancer is the most frequently diagnosed cancer in women, being also the leading cause of cancer death among female population, including in Romania. Resistance to therapy represents a major problem for cancer treatment. Current cancer treatments are both expensive and induce serious side effects; therefore ineffective therapies are both traumatic and pricy. Characterizing predictive markers that can identify high-risk patients could contribute to dedicated/personalized therapy to improve the life quality and expectancy of cancer patients. Moreover, there are some markers that govern specific tumor molecular features that can be targeted with specific therapies for those patients who are most likely to benefit. The identification of stem cells in both normal and malignant breast tissue have lead to the hypothesis that breast tumors arise from breast cancer stem-like cells (CSCs), and that these cells influence tumor’s response to therapy. CSCs have similar self-renewal properties to normal stem cells, however the balance between the signaling pathways is altered towards tumor formation In this review, we discuss the molecular aspects of breast CSCs and the controversies regarding their use in the diagnosis and treatment decision of breast cancer patients.

Overcoming Hypoxia-Mediated Tumor Progression: Combinatorial Approaches Targeting pH Regulation, Angiogenesis and Immune Dysfunction

Hypoxia is an important contributor to the heterogeneity of the microenvironment of solid tumors and is a significant environmental stressor that drives adaptations which are essential for the survival and metastatic capabilities of tumor cells. Critical adaptive mechanisms include altered metabolism, pH regulation, epithelial-mesenchymal transition, angiogenesis, migration/invasion, diminished response to immune cells and resistance to chemotherapy and radiation therapy. In particular, pH regulation by hypoxic tumor cells, through the modulation of cell surface molecules such as extracellular carbonic anhydrases (CAIX and CAXII) and monocarboxylate transporters (MCT-1 and MCT-4) functions to increase cancer cell survival and enhance cell invasion while also contributing to immune evasion. Indeed, CAIX is a vital regulator of hypoxia mediated tumor progression, and targeted inhibition of its function results in reduced tumor growth, metastasis, and cancer stem cell function. However, the integrated contributions of the repertoire of hypoxia-induced effectors of pH regulation for tumor survival and invasion remain to be fully explored and exploited as therapeutic avenues. For example, the clinical use of anti-angiogenic agents has identified a conundrum whereby this treatment increases hypoxia and cancer stem cell components of tumors, and accelerates metastasis. Furthermore, hypoxia results in the infiltration of myeloid-derived suppressor cells (MDSCs), regulatory T cells (Treg) and Tumor Associated Macrophages (TAMs), and also stimulates the expression of PD-L1 on tumor cells, which collectively suppress T-cell mediated tumor cell killing. Therefore, combinatorial targeting of angiogenesis, the immune system and pH regulation in the context of hypoxia may lead to more effective strategies for curbing tumor progression and therapeutic resistance, thereby increasing therapeutic efficacy and leading to more effective strategies for the treatment of patients with aggressive cancer.

Prognostic Significance of Carbonic Anhydrase IX Expression in Cancer Patients: A Meta-Analysis

Hypoxia is a characteristic of many solid tumors and an adverse prognostic factor for treatment outcome. Hypoxia increases the expression of carbonic anhydrase IX (CAIX), an enzyme that is predominantly found on tumor cells and is involved in maintaining the cellular pH balance. Many clinical studies investigated the prognostic value of CAIX expression, but most have been inconclusive, partly due to small numbers of patients included. The present meta-analysis was therefore performed utilizing the results of all clinical studies to determine the prognostic value of CAIX expression in solid tumors. Renal cell carcinoma was excluded from this meta-analysis due to an alternative mechanism of upregulation. 958 papers were identified from a literature search performed in PubMed and Embase. These papers were independently evaluated by two reviewers and 147 studies were included in the analysis. The meta-analysis revealed strong significant associations between CAIX expression and all endpoints: overall survival [hazard ratio (HR) = 1.76, 95% confidence interval (95%CI) 1.58–1.98], disease-free survival (HR = 1.87, 95%CI 1.62–2.16), locoregional control (HR = 1.54, 95%CI 1.22–1.93), disease-specific survival (HR = 1.78, 95%CI 1.41–2.25), metastasis-free survival (HR = 1.82, 95%CI 1.33–2.50), and progression-free survival (HR = 1.58, 95%CI 1.27–1.96). Subgroup analyses revealed similar associations in the majority of tumor sites and types. In conclusion, these results show that patients having tumors with high CAIX expression have higher risk of locoregional failure, disease progression, and higher risk to develop metastases, independent of tumor type or site. The results of this meta-analysis further support the development of a clinical test to determine patient prognosis based on CAIX expression and may have important implications for the development of new treatment strategies.

[Cancer stem cell markers and their prognostic value]

Based on an analysis of a large number of sources of literature, the paper gives general information on the markers for cancer stem cells (CSCs), which allow the detection of this rare cell subpopulation, on the possibilities of estimating their immunohistochemical or immunofluorescent expression in tumors, and on the prognostic and predictive values of these molecules. For their detection, investigators generally use definite molecules, the so-called markers of CSCs, among which there are CD44, CD133, CD24, aldehyde dehydrogenase, and others. The expression of these molecules in the tumor tissue obtained from patients affects survival rates and permits the prediction of a response to therapy. A better insight into the immunophenotype of CSCs, the role of CSC markers in retaining the special properties of this call population, and the clinical significance of the expression of CSC markers will be able to elaborate new approaches to therapy for malignancies.

Association between ALDH1+/CD133+ stem-like cells and tumor angiogenesis in invasive ductal breast carcinoma

The growth and metastasis of tumors is dependent on angiogenesis; however, the association between tumor stem cells (TSCs) and tumor angiogenesis remains to be elucidated. The present study aimed to investigate the expression of the TSC markers aldehyde dehydrogenase 1 (ALDH1) and cluster of differentiation 133 (CD133) in invasive ductal breast carcinoma, and identify their correlation with tumor angiogenesis. Stem-like cells from the breast tissue of 120 patients, who were diagnosed with invasive ductal breast carcinoma at The First Affiliated Hospital of Zhengzhou University (Zhengzhou, Henan, China) between January 2009 and December 2010, were collected by surgical resection and analyzed using immunohistochemical double staining. The expression of the vascular markers CD34, CD105 and vascular endothelial growth factor (VEGF) were determined using single staining. Overall, 25.83% (31/120) of the specimens contained a large number of ALDH1+/CD133+ stem-like cells (ALDH1+/CD133+ tumor). ALDH1+/CD133+ expression is associated with microvessel density, VEGF-positive rate and estrogen receptor expression (P<0.05); however, ALDH1+/CD133+ expression was not associated with age, tumor diameter, lymph node metastasis, histological classification, progesterone receptor expression or human epidermal growth factor receptor 2 expression (P>0.05). The ALDH1+/CD133+ tumor phenotype and expression of VEGF were identified to be correlated in the present study (P=0.020). The present study revealed a close association between breast cancer TSC markers, including ALDH1 and CD133, and tumor angiogenesis. The results of the present study may provide a novel target and treatment strategy for future studies investigating tumor growth and metastasis.

The Proportion of ALDEFLUOR-Positive Cancer Stem Cells Changes with Cell Culture Density Due to the Expression of Different ALDH Isoforms

A significant number of discrepancies exist within the literature regarding ALDEFLUOR-positive stem cell populations in cell lines. We hypothesized that these inconsistencies resulted from differences in culture conditions, particularly cell density. We cultured several colon cancer cell lines (N=8) at high and low densities and found a significant decrease in ALDEFLUOR-positive cell populations at high density. However, we found no changes in the CD166-positive stem cell population, self-renewal, or cell cycle distribution of cells cultured at different densities. Interestingly, when we sorted both ALDEFLUOR positive and negative populations from the different density cultures, we identified a significant number of Aldehyde dehydrogenase (ALDH) isoforms whose expression was decreased in ALDEFLUOR-positive stem cells cultured at high density. This novel finding suggests that multiple ALDH isoforms contribute to ALDEFLUOR activity in colon cancer stem cells and decreases in ALDEFLUOR-positive stem cells at high cell density are due to decreased expression of multiple ALDH isoforms. Thus, designing therapeutics to target ALDEFLUOR-positive cancer stem cells may require inhibition of multiple ALDH isoforms.

Immunohistochemical analysis of aldehyde dehydrogenase isoforms and their association with estrogen-receptor status and disease progression in breast cancer

In many types of tumors, especially breast tumors, aldehyde dehydrogenase (ALDH) activity has been used to identify cancer stem-like cells within the tumor. The presence and quantity of these cells are believed to predict the response of tumors to chemotherapy. Therefore, identification and eradication of these cells would be necessary to cure the patient. However, there are 19 different ALDH isoforms that could contribute to the enzyme activity. ALDH1A1 and ALDH1A3 are among the isoforms mostly responsible for the increased ALDH activity observed in these stem-like cells, although the main isoforms vary in different tissues and tumor types. In the study reported here, we attempted to determine if ALDH1A1 or ALDH1A3, specifically, correlate with tumor stage, grade, and hormone-receptor status in breast-cancer patients. While there was no significant correlation between ALDH1A1 and any of the parameters tested, we were able to identify a positive correlation between ALDH1A3 and tumor stage in triple-negative cancers. In addition, ALDH1A3 was negatively correlated with estrogen-receptor status. Our data suggest that ALDH1A3 could be utilized as a marker to identify stem-like cells within triple-negative tumors.

Predictive gene signature of response to the anti-TweakR mAb PDL192 in patient-derived breast cancer xenografts

Purpose

(1) To determine TweakR expression in human breast cancers (BC), (2) evaluate the antitumor effect of the anti-TweakR antibody PDL192, used alone or after chemotherapy-induced complete remission (CR), on patient-derived BC xenografts (PDX) and (3) define predictive markers of response.

Experimental Design

TweakR expression was analyzed by IHC on patients and PDXs BC samples. In vivo antitumor effect of PDL192 was evaluated on eight TweakR-positive BC PDXs alone or after complete remission induced by a combination of doxorubicin and cyclophosphamide. Using both responding and resistant PDX tumors after PDL192 administration, RT-QPCR were performed on a wide list of selected candidate genes to identify predictive markers of response.

Results

TweakR protein was expressed in about half of human BC samples. In vivo PDL192 treatment had significantly anti-tumor activity in 4 of 8 TweakR-positive BC PDXs, but no correlation between the expression level of the Tweak receptor and response to therapy was observed. PDL192 also significantly delayed tumor relapse after CR. Finally, an 8 gene signature was defined from sensitive and resistant PDXs.

Conclusions

PDL192 was highly efficient in some BC PDXs. We found 8 genes that were differentially expressed in responding and resistant tumors and could constitute a gene expression signature which would need to be extended to other xenograft models for confirmation. These data confirm the therapeutic potential of TweakR targeting in BC and the possibility of prospectively selecting patients who might benefit from therapy.

Hypoxia-induced carbonic anhydrase IX as a target for cancer therapy: from biology to clinical use

The tumor microenvironment includes a complicated network of physiological gradients contributing to plasticity of tumor cells and heterogeneity of tumor tissue. Hypoxia is a key component generating intratumoral oxygen gradients, which affect the cellular expression program and lead to therapy resistance and increased metastatic propensity of weakly oxygenated cell subpopulations. One of the adaptive responses of tumor cells to hypoxia involves the increased expression and functional activation of carbonic anhydrase IX (CA IX), a cancer-related cell surface enzyme catalyzing the reversible conversion of carbon dioxide to bicarbonate ion and proton. Via its catalytic activity, CA IX participates in regulation of intracellular and extracellular pH perturbations that result from hypoxia-induced changes in cellular metabolism producing excess of acid. Through the ability to regulate pH, CA IX also facilitates cell migration and invasion. In addition, CA IX has non-catalytic function in cell adhesion and spreading. Thus, CA IX endows tumor cells with survival advantages in hypoxia/acidosis and confers an increased ability to migrate, invade and metastasize. Accordingly, CA IX is expressed in a broad range of tumors, where it is associated with prognosis and therapy outcome. Its expression pattern and functional implications in tumor biology make CA IX a promising therapeutic target, which can be hit either by immunotherapy with monoclonal antibodies or with compounds inhibiting its enzyme activity. The first strategy has already reached the clinical trials, whereas the second one is still in preclinical testing. Both strategies indicate that CA IX can become a clinically useful anticancer target, but urge further efforts toward better selection of patients for immunotherapy and deeper understanding of tumor types, clinical situations and synthetic lethality interactions with other treatment approaches.

Clinicopathologic characteristics of breast cancer stem cells identified on the basis of aldehyde dehydrogenase 1 expression

Purpose

Breast cancer displays varying molecular and clinical features. The ability to form breast tumors has been shown by several studies with aldehyde dehydrogenase 1 (ALDH1) positive cells. The aim of this study is to investigate the association between ALDH1 expression and clinicopathologic characteristics of invasive ductal carcinoma.

Methods

We investigated breast cancer tissues for the prevalence of ALDH1⁺ tumor cells and their prognostic value. The present study included paraffin-embedded tissues of 70 patients with or without recurrences. We applied immunohistochemical staining for the detection of ALDH1⁺ cells. Analysis of the association of clinical outcomes and molecular subtype with marker status was conducted.

Results

ALDH1⁺ and ALDH1^- tumors were more frequent in triple-negative breast cancers and in luminal A breast cancers, respectively (p<0.01). ALDH1 expression was found to exert significant impact on disease free survival (DFS) (ALDH1⁺ vs. ALDH1^-, 53.1±6.7 months vs. 79.2±4.7 months; p=0.03) and overall survival (OS) (ALDH1⁺ vs. ALDH1^-, 68.5±4.7 months vs. 95.3±1.1 months; p<0.01). In triple-negative breast cancer (TNBC) patients, DFS and OS showed no statistical differences according to ALDH1 expression (ALDH1⁺ vs. ALDH1^-, 45.3±9.4 months vs. 81.3±7.4 months, p=0.52; 69.0±7.5 months vs. 91.3±6.3 months, p=0.67). However, non-TNBC patients showed significant OS difference between ALDH1⁺ and ALDH1^- tumors (ALDH1⁺ vs. ALDH1^-, 77.6±3.6 months vs. 98.0±1.0 months; p=0.04) with no statistical difference of DFS (ALDH1⁺ vs. ALDH1^-, 60.5±8.0 months vs. 81.8±4.6 months; p=0.27).

Conclusion

Our findings suggest that the expression of ALDH1 in breast cancer may be associated with TNBC and poor clinical outcomes. On the basis of our findings, we propose that ALDH1 expression in breast cancer could be correlated with poor prognosis, and may contribute to a more aggressive cancer phenotype.

The expression of aldehyde dehydrogenase family in breast cancer

Purpose

It is widely accepted that aldehyde dehydrogenase (ALDH) activity is a signature of breast cancer stem cells, and high activity has been reported to be associated with poor clinical outcome. The aim of this study was to assess the expression of members of the ALDH family of isozymes in breast cancer tissues and to evaluate the implications of the results.

Methods

We analyzed paraffin-embedded tumor tissue from 160 patients with breast cancer. Immunohistochemistry (IHC) staining was performed on the slides using antibodies against different ALDH family members. We collated the IHC results with patient clinical characteristics and determined their prognostic value. In addition, we analyzed normal, hyperplastic, and carcinomatous tissues in situ to check their ALDH distributions.

Results

All the tested ALDH members were detected in the various tissue types, but at different levels. Only ALDH 1A3 was found to be significantly associated with distant metastasis (p=0.001), disease-free survival (p<0.001), and overall survival (p<0.001).

Conclusion

The level of ALDH 1A3 in breast cancer tissue is a predictive marker of a poor clinical outcome.

The quinoxaline di-N-oxide DCQ blocks breast cancer metastasis in vitro and in vivo by targeting the hypoxia inducible factor-1 pathway

Background

Although tumor hypoxia poses challenges against conventional cancer treatments, it provides a therapeutic target for hypoxia-activated drugs. Here, we studied the effect of the hypoxia-activated synthetic quinoxaline di-N-oxide DCQ against breast cancer metastasis and identified the underlying mechanisms.

Methods

The human breast cancer cell lines MCF-7 (p53 wildtype) and MDA-MB-231 (p53 mutant) were treated with DCQ under normoxia or hypoxia. Drug toxicity on non-cancerous MCF-10A breast cells was also determined. In vitro cellular responses were investigated by flow cytometry, transfection, western blotting, ELISA and migration assays. The anti-metastatic effect of DCQ was validated in the MDA-MB-231 xenograft mouse model.

Results

DCQ selectively induced apoptosis in both human breast cancer cells preferentially under hypoxia without affecting the viability of non-cancerous MCF-10A. Cancer cell death was associated with an increase in reactive oxygen species (ROS) independently of p53 and was inhibited by antioxidants. DCQ-induced ROS was associated with DNA damage, the downregulation of hypoxia inducible factor-1 alpha (HIF-1α), and inhibition of vascular endothelial growth factor (VEGF) secretion. In MCF-7, HIF-1α inhibition was partially via p53-activation and was accompanied by a decrease in p-mTOR protein, suggesting interference with HIF-1α translation. In MDA-MB-231, DCQ reduced HIF-1α through proteasomal-dependent degradation mechanisms. HIF-1α inhibition by DCQ blocked VEGF secretion and invasion in MCF-7 and led to the inhibition of TWIST in MDA-MB-231. Consistently, DCQ exhibited robust antitumor activity in MDA-MB-231 breast cancer mouse xenografts, enhanced animal survival, and reduced metastatic dissemination to lungs and liver.

Conclusion

DCQ is the first hypoxia-activated drug showing anti-metastatic effects against breast cancer, suggesting its potential use for breast cancer therapy.

The quinoxaline di-N-oxide DCQ blocks breast cancer metastasis in vitro and in vivo by targeting the hypoxia inducible factor-1 pathway

BACKGROUND

Although tumor hypoxia poses challenges against conventional cancer treatments, it provides a therapeutic target for hypoxia-activated drugs. Here, we studied the effect of the hypoxia-activated synthetic quinoxaline di-N-oxide DCQ against breast cancer metastasis and identified the underlying mechanisms.

METHODS

The human breast cancer cell lines MCF-7 (p53 wildtype) and MDA-MB-231 (p53 mutant) were treated with DCQ under normoxia or hypoxia. Drug toxicity on non-cancerous MCF-10A breast cells was also determined. In vitro cellular responses were investigated by flow cytometry, transfection, western blotting, ELISA and migration assays. The anti-metastatic effect of DCQ was validated in the MDA-MB-231 xenograft mouse model.

RESULTS

DCQ selectively induced apoptosis in both human breast cancer cells preferentially under hypoxia without affecting the viability of non-cancerous MCF-10A. Cancer cell death was associated with an increase in reactive oxygen species (ROS) independently of p53 and was inhibited by antioxidants. DCQ-induced ROS was associated with DNA damage, the downregulation of hypoxia inducible factor-1 alpha (HIF-1α), and inhibition of vascular endothelial growth factor (VEGF) secretion. In MCF-7, HIF-1α inhibition was partially via p53-activation and was accompanied by a decrease in p-mTOR protein, suggesting interference with HIF-1α translation. In MDA-MB-231, DCQ reduced HIF-1α through proteasomal-dependent degradation mechanisms. HIF-1α inhibition by DCQ blocked VEGF secretion and invasion in MCF-7 and led to the inhibition of TWIST in MDA-MB-231. Consistently, DCQ exhibited robust antitumor activity in MDA-MB-231 breast cancer mouse xenografts, enhanced animal survival, and reduced metastatic dissemination to lungs and liver.

CONCLUSION

DCQ is the first hypoxia-activated drug showing anti-metastatic effects against breast cancer, suggesting its potential use for breast cancer therapy.