Distinct prognostic values of ALDH1 isoenzymes in breast cancer

Innate differences in the molecular signature of normal inferior & superior human parathyroid glands: potential implications for parathyroid adenoma

Primary hyperparathyroidism is a common endocrine disorder. Interestingly, the majority (75%) of parathyroid tumors are localized to the inferior parathyroid glands. To date, the reason for this natural bias has not been investigated. We assessed the global gene expression profile of superior and inferior glands obtained from forensic autopsies. The genes with significant differential expression between superior and inferior parathyroids were further assessed by RT-PCR in 19 pairs. As an iterative approach, additional genes with an established role in parathyroid disorders, i.e., CASR, MAFB, PAX9, TBCE, TBX1, VDR, MEN1, CCND1, and CDC73 were also evaluated by RT-PCR in all 19 pairs of superior and inferior parathyroid glands. Seven homeobox genes, namely HOXA4, HOXA5, HOXBAS3, HOXB4, HOXB6, HOXB9, IRX1, and one encoding for ALDH1A2 showed a lower expression in the inferior parathyroid glands than in the superior. Conversely, SLC6A1 showed a higher expression in the inferior glands. Of the nine genes with significant differential mRNA expression among superior and inferior glands HOXB9, HOXB4 and IRX1 could be detected by western blotting/mass spectrometry. The study is the first to show the differential expression of nine genes HOXA4, HOXA5, HOXBAS3, HOXB4, HOXB6, HOXB9, IRX1, ALDH1A2, and SLC6A1 in inferior versus the superior parathyroid glands. This could have potential implications for the preferential localization of parathyroid tumors to the inferior parathyroid glands as observed in patients with primary hyperparathyroidism.

Aldehyde dehydrogenase in solid tumors and other diseases: Potential biomarkers and therapeutic targets

The family of aldehyde dehydrogenases (ALDHs) contains 19 isozymes and is involved in the oxidation of endogenous and exogenous aldehydes to carboxylic acids, which contributes to cellular and tissue homeostasis. ALDHs play essential parts in detoxification, biosynthesis, and antioxidants, which are of important value for cell proliferation, differentiation, and survival in normal body tissues. However, ALDHs are frequently dysregulated and associated with various diseases like Alzheimer's disease, Parkinson's disease, and especially solid tumors. Notably, the involvement of the ALDHs in tumor progression is responsible for the maintenance of the stem-cell-like phenotype, triggering rapid and aggressive clinical progressions. ALDHs have captured increasing attention as biomarkers for disease diagnosis and prognosis. Nevertheless, these require further longitudinal clinical studies in large populations for broad application. This review summarizes our current knowledge regarding ALDHs as potential biomarkers in tumors and several non-tumor diseases, as well as recent advances in our understanding of the functions and underlying molecular mechanisms of ALDHs in disease development. Finally, we discuss the therapeutic potential of ALDHs in diseases, especially in tumor therapy with an emphasis on their clinical implications.

Dissecting Molecular Heterogeneity of Circulating Tumor Cells (CTCs) from Metastatic Breast Cancer Patients through Copy Number Aberration (CNA) and Single Nucleotide Variant (SNV) Single Cell Analysis

Circulating tumor cells' (CTCs) heterogeneity contributes to counteract their introduction in clinical practice. Through single-cell sequencing we aim at exploring CTC heterogeneity in metastatic breast cancer (MBC) patients. Single CTCs were isolated using DEPArray NxT. After whole genome amplification, libraries were prepared for copy number aberration (CNA) and single nucleotide variant (SNV) analysis and sequenced using Ion GeneStudio S5 and Illumina MiSeq, respectively. CTCs demonstrate distinctive mutational signatures but retain molecular traces of their common origin. CNA profiling identifies frequent aberrations involving critical genes in pathogenesis: gains of 1q (CCND1) and 11q (WNT3A), loss of 22q (CHEK2). The longitudinal single-CTC analysis allows tracking of clonal selection and the emergence of resistance-associated aberrations, such as gain of a region in 12q (CDK4). A group composed of CTCs from different patients sharing common traits emerges. Further analyses identify losses of 15q and enrichment of terms associated with pseudopodium formation as frequent and exclusive events. CTCs from MBC patients are heterogeneous, especially concerning their mutational status. The single-cell analysis allows the identification of aberrations associated with resistance, and is a candidate tool to better address treatment strategy. The translational significance of the group populated by similar CTCs should be elucidated.

Inhibitor of Growth 4 (ING4) Plays a Tumor-Repressing Role in Oral Squamous Cell Carcinoma via Nuclear Factor kappa-B (NF-kB)/DNA Methyltransferase 1 (DNMT1) Axis-Mediated Regulation of Aldehyde Dehydrogenase 1A2 (ALDH1A2)

BACKGROUND

Inhibitor of growth 4 (ING4) level was reported to be decreased in head and neck squamous cell carcinoma (HNSC) tissue, however, it is unknown whether and how ING4 participates in regulating the development of oral squamous cell carcinoma (OSCC).

OBJECTIVE

To investigate the role and mechanism of ING4 in OSCC.

METHODS

ING4 was forced up-or down-regulated in two OSCC cell lines, and its effects on the malignant behavior of OSCC cells were investigated in vitro. The ubiquitination level of NF-kB p65 in ING4 upregulated cells was measured by co-immunoprecipitation. Moreover, the effects of ING4 on the methylation level of ALDH1A2 were evaluated by methylation-specific polymerase chain reaction (MSP) assay. The role of ING4 in OSCC growth in vivo was observed in nude mice.

RESULTS

Our results showed that the expression of ING4 in OSCC cell lines was lower than that in normal oral keratinocyte cells. In vitro, ING4 overexpression inhibited the proliferation, migration, and invasion of OSCC cell lines and ING4 silencing exhibited opposite results. We also demonstrated that ING4 overexpression promoted the ubiquitination and degradation of P65 and reduced DNA methyltransferase 1 (DNMT1) expression, and Aldehyde dehydrogenase 1A2 (ALDH1A2) methylation. Moreover, overexpression of p65 rescued the suppression of malignant behavior, induced by ING4 overexpression. In addition, ING4 negatively regulated the growth of OSCC xenograft tumors in vivo.

CONCLUSION

Our data evidenced that ING4 played a tumor-repressing role in OSCC in vivo and in vitro via NF-κB/DNMT1/ALDH1A2 axis.

Epigenetic study of early breast cancer (EBC) based on DNA methylation and gene integration analysis

Breast cancer (BC) is one of the leading causes of cancer-related deaths in women. The purpose of this study is to identify key molecular markers related to the diagnosis and prognosis of early breast cancer (EBC). The data of mRNA, lncRNA and DNA methylation were downloaded from The Cancer Genome Atlas (TCGA) dataset for identification of differentially expressed mRNAs (DEmRNAs), differentially expressed lncRNAs (DElncRNAs) and DNA methylation analysis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyzes were used to identify the biological functions of DEmRNAs. The correlation analysis between DNA methylation and DEmRNAs was carried out. Then, diagnostic analysis and prognostic analysis of identified DEmRNAs and DElncRNAs were also performed in the TCGA database. Subsequently, methylation state verification for identified DEmRNAs was performed in the GSE32393 dataset. In addition, real-time polymerase chain reaction (RT-PCR) in vitro verification of genes was performed. Finally, AC093110.1 was overexpressed in human BC cell line MCF-7 to verify cell proliferation and migration. In this study, a total of 1633 DEmRNAs, 750 DElncRNAs and 8042 differentially methylated sites were obtained, respectively. In the Venn analysis, 11 keys DEmRNAs (ALDH1L1, SPTBN1, MRGPRF, CAV2, HSPB6, PITX1, WDR86, PENK, CACNA1H, ALDH1A2 and MME) were we found. ALDH1A2, ALDH1L1, HSPB6, MME, MRGPRF, PENK, PITX1, SPTBN1, WDR86 and CAV2 may be considered as potential diagnostic gene biomarkers in EBC. Strikingly, CAV2, MME, AC093110.1 and AC120498.6 were significantly actively correlated with survival. Methylation state of identified DEmRNAs in GSE32393 dataset was consistent with the result in TCGA. AC093110.1 can affect the proliferation and migration of MCF-7. ALDH1A2, ALDH1L1, HSPB6, MME, MRGPRF, PENK, PITX1, SPTBN1, WDR86 and CAV2 may be potential diagnostic gene biomarkers of EBC. Strikingly, CAV2, MME, AC093110.1 and AC120498.6 were significantly actively correlated with survival. The identification of these genes can help in the early diagnosis and treatment of EBC. In addition, AC093110.1 can regulate SPTBN1 expression and play an important role in cell proliferation and migration, which provides clues to clarify the regulatory mechanism of EBC.

Metabolic Response of Triple-Negative Breast Cancer to Folate Restriction

Background: Triple-negative breast cancers (TNBCs), accounting for approximately 15% of breast cancers, lack targeted therapy. A hallmark of cancer is metabolic reprogramming, with one-carbon metabolism essential to many processes altered in tumor cells, including nucleotide biosynthesis and antioxidant defenses. We reported that folate deficiency via folic acid (FA) withdrawal in several TNBC cell lines results in heterogenous effects on cell growth, metabolic reprogramming, and mitochondrial impairment. To elucidate underlying drivers of TNBC sensitivity to folate stress, we characterized in vivo and in vitro responses to FA restriction in two TNBC models differing in metastatic potential and innate mitochondrial dysfunction. Methods: Metastatic MDA-MB-231 cells (high mitochondrial dysfunction) and nonmetastatic M-Wnt cells (low mitochondrial dysfunction) were orthotopically injected into mice fed diets with either 2 ppm FA (control), 0 ppm FA, or 12 ppm FA (supplementation; in MDA-MB-231 only). Tumor growth, metabolomics, and metabolic gene expression were assessed. MDA-MB-231 and M-Wnt cells were also grown in media with 0 or 2.2 µM FA; metabolic alterations were assessed by extracellular flux analysis, flow cytometry, and qPCR. Results: Relative to control, dietary FA restriction decreased MDA-MB-231 tumor weight and volume, while FA supplementation minimally increased MDA-MB-231 tumor weight. Metabolic studies in vivo and in vitro using MDA-MB-231 cells showed FA restriction remodeled one-carbon metabolism, nucleotide biosynthesis, and glucose metabolism. In contrast to findings in the MDA-MB-231 model, FA restriction in the M-Wnt model, relative to control, led to accelerated tumor growth, minimal metabolic changes, and modest mitochondrial dysfunction. Increased mitochondrial dysfunction in M-Wnt cells, induced via chloramphenicol, significantly enhanced responsiveness to the cytotoxic effects of FA restriction. Conclusions: Given the lack of targeted treatment options for TNBC, uncovering metabolic vulnerabilities that can be exploited as therapeutic targets is an important goal. Our findings suggest that a major driver of TNBC sensitivity to folate restriction is a high innate level of mitochondrial dysfunction, which can increase dependence on one-carbon metabolism. Thus, folate deprivation or antifolate therapy for TNBCs with metabolic inflexibility due to their elevated levels of mitochondrial dysfunction may represent a novel precision-medicine strategy.

Distinct prognostic values and antitumor effects of tumor growth factor β1 and its receptors in gastric cancer

Gastric cancer (GC) is one of the most common malignancies and is the second leading cause of cancer-associated mortality world-wide. In the present study, the prognostic value and antitumor effects of transforming growth factor β1 (TGFβ1) and its receptors in GC were explored. The online Kaplan-Meier plotter database was used to investigate the prognostic values of TGFβ1 and its receptors. The present study demonstrated that low mRNA expression levels of TGFβ1 and its 3 receptors, transforming growth factor β1 (TGFβR1), TGFβR2 and TGFβR3, was associated with improved overall survival time in patients with GC. Cell Counting Kit-8 and Transwell assays were used to confirm the effects of TGFβ1, TGFβR1, TGFβR2 and TGFβR3 on the proliferation, migration and invasiveness of the AGS and MKN45 GC cell lines. It was found that the knockdown of these genes blocked cell proliferation, migration and invasion in GC cells. To the best of our knowledge, the present study is the first to determine the role of TGFβR1 and TGFβR3 in GC cells. The results indicate that in addition to TGFβ1 and TGFβR2, TGFβR1 also plays a specific role in the occurrence and development of tumors. Thus, these markers may be considered as potential prognostic indicators in human GC. The findings of the present study indicate that not only TGFβ1 and TGFβR2, but also TGFβR1 is involved in the progression of GC. The findings of the present study provide new ideas and approaches for the treatment of patients with GC.

Distinct functions and prognostic values of RORs in gastric cancer

Retinoic acid receptor-related orphan receptors (RORs) are frequently abnormally expressed in several human malignancies, including gastric cancer (GC). RORs are involved in the development and progression of GC through Wnt signaling pathway receptors and other common receptors. However, the prognostic roles of individual RORs in patients with GC remain elusive. We accessed the prognostic roles of three RORs (RORα, RORβ, and RORγ) through "The Kaplan-Meier plotter" (KM plotter) database in patients with GC. For all patients with GC who were followed for 20 years, the low mRNA expression of all three RORs showed a significant correlation with better outcomes. We further accessed the prognostic value of individual RORs in different clinical pathological features including Lauren classification, clinical stages, pathological grades, HER2 status, and different treatments methods. The RORs demonstrated critical prognostic roles in GC. Expressions of RORs were higher in GC tissues when compared with normal gastric tissues. Moreover, knockdown of RORs significantly inhibited cell proliferation and migration, suggesting an oncogenic role of RORs in human GC. These findings suggest potential roles of RORs as biomarkers for GC prognosis and as oncogenes in GC.

Validation of Gene Profiles for Analysis of Regional Lymphatic Metastases in Head and Neck Squamous Cell Carcinoma

The progress of Head and Neck Squamous Cell Carcinoma (HNSCC) is dependent on both cancer stem cells (CSCs) and immune suppression. This study was designed to evaluate the distribution of CSCs and the characteristic immune suppression status in HNSCC primary tumors and lymph nodes. A total of 303 lymph nodes from 25 patients, as well as tumor and adjacent normal tissue samples, were evaluated by a quantitative PCR assay of the markers of CSCs and the characteristic immune suppression. Expressions of selected genes in The Cancer Genome Atlas (TCGA) datasets were also analyzed. In the primary tumors, we found that expressions of CSCs markers (ALDH1L1, PECAM1, PROM1) were down-regulated, while immune suppression markers FOXP3, CD47, EGFR, SOX2, and TGFB1 were up-regulated significantly when compared to that in adjacent normal tissues. In the lymph nodes, expressions of both CSCs, and immune suppression markers were upregulated significantly compared with that in primary tumors. The mRNA expression of selected CSCs and immune suppression markers exhibited the highest expression in the level II of metastasis, then declined in the level III and remained constant at a reduced value in levels IV and V of metastases. These results reveal a comprehensive understanding of the unique genetic characteristics associated with metastatic loci and potential routes of lymphatic dissemination of HNSCC, which helps to explain why the level II has a high incidence of lymph node metastasis, and why skip metastasis straight to the level IV or level V is rarely found in the clinic.

Doxorubicin and α-Mangostin oppositely affect luminal breast cancer cell stemness evaluated by a new retinaldehyde-dependent ALDH assay in MCF-7 tumor spheroids

According to cancer stem cell theory, only a limited number of self-renewing and cloning cells are responsible for tumor relapse after a period of remittance. The aim of the present study was to investigate the effects of Doxorubicin and α-Mangostin, two antiproliferative drugs, on both tumor bulk and stem cells in multicellular tumor spheroids originated from the luminal MCF-7 breast cancer cell line. A new and original fluorimetric assay was used to selectively measure the activity of the retinaldehyde-dependent isoenzymes of aldehyde dehydrogenase (RALDH), which are markers of a subpopulation of breast cancer stem cells. The administration of 5 μg/ml (12.2 μM) α-Mangostin for 48 h provoked: i) a marked disaggregation of the spheroids, leading to a doubling of their volume (p < 0.01), ii) a 40 % decrease in cell viability (p < 0.01), evaluated by the acid phosphatase assay, and iii) a reduction by more than 90 % of RALDH activity. By contrast, Doxorubicin given for 48 h in the range of 0.1-40 μM did not significantly reduce cell viability and caused only a modest modification of the spheroid morphology. Moreover, 40 μM Doxorubicin increased RALDH activity 2.5-fold compared to the untreated sample. When the two drugs were administered together using 5 μg/ml α-Mangostin, the IC₅₀ of Doxorubicin referred to cell viability decreased six-fold and the RALDH activity was further reduced. In conclusion, the combined administration of Doxorubicin and α-Mangostin provoked a significant cytotoxicity and a remarkable inhibition of RALDH activity in MCF-7 tumor spheroids, suggesting that these drugs could be effective in reducing cell stemness in luminal breast cancer.

ALDH1A2 Is a Candidate Tumor Suppressor Gene in Ovarian Cancer

Aldehyde dehydrogenase 1 family member A2 (ALDH1A2) is a rate-limiting enzyme involved in cellular retinoic acid synthesis. However, its functional role in ovarian cancer remains elusive. Here, we found that ALDH1A2 was the most prominently downregulated gene among ALDH family members in ovarian cancer cells, according to complementary DNA microarray data. Low ALDH1A2 expression was associated with unfavorable prognosis and shorter disease-free and overall survival for ovarian cancer patients. Notably, hypermethylation of ALDH1A2 was significantly higher in ovarian cancer cell lines when compared to that in immortalized human ovarian surface epithelial cell lines. ALDH1A2 expression was restored in various ovarian cancer cell lines after treatment with the DNA methylation inhibitor 5-aza-2'-deoxycytidine. Furthermore, silencing DNA methyltransferase 1 (DNMT1) or 3B (DNMT3B) restored ALDH1A2 expression in ovarian cancer cell lines. Functional studies revealed that forced ALDH1A2 expression significantly impaired the proliferation of ovarian cancer cells and their invasive activity. To the best of our knowledge, this is the first study to show that ALDH1A2 expression is regulated by the epigenetic regulation of DNMTs, and subsequently that it might act as a tumor suppressor in ovarian cancer, further suggesting that enhancing ALDH1A2-linked signaling might provide new opportunities for therapeutic intervention in ovarian cancer.

Clinical implications of ALDH1A1 and ALDH1A3 mRNA expression in melanoma subtypes

Aldehyde dehydrogenase (ALDH) activity is not only a valuable marker for cancer cells with stem-like features, but also plays a vital role in drug resistance and disease progression in many tumors including melanoma. However, the precise role of ALDH activity in patient prognosis remains unclear. In this study, using the Cancer Genome Atlas (TCGA) RNA-sequencing expression data, we analyzed gene expression of ALDH isozymes in melanoma tumors to define the expression patterns and the prognostic and predictive values of these enzymes. We found that ALDH1A1 and ALDH1A3 had both higher and broader expression ranges in melanoma patients, and that ALDH1A3 expression correlated with better overall survival in metastatic melanoma. Further, stratification of the TCGA cohorts by the mutational subtypes of melanoma specifically revealed that expression of ALDH1A3 correlated with better prognosis in metastatic BRAF-mutant melanoma while expression of ALDH1A1 correlated with better prognosis in BRAF wild-type melanoma. Gene set enrichment analysis (GSEA) of these cohorts identified upregulation in oxidative phosphorylation, adipogenesis, and fatty acid metabolism signaling in ALDH1A^lo patients, suggesting BRAF/MEK inhibitor resistance in that subset of patients. On the other hand, GSEA of ALDH1A3^hi cohorts revealed upregulation in glycolysis, hypoxia and angiogenesis, suggesting BRAF/MEK inhibitor sensitivity in that subset of patients. Gene expression analysis using pre-treatment tumor samples supports high ALDH1A3 expression before BRAF/MEK inhibitor treatment as predictive of better treatment response in BRAF-mutant melanoma patients. Our study provides evidence that high ALDH1A3 mRNA expression is not only a prognostic marker but also a predictive marker for BRAF/MEK inhibitor treatment response in BRAF-mutant metastatic melanoma patients.

MiR-124 reversed the doxorubicin resistance of breast cancer stem cells through STAT3/HIF-1 signaling pathways

Various drug treatments including doxorubicin (DOX) have been proved efficient in the suppression of breast cancer. Nonetheless, drug resistance became an obstacle in the therapeutic process. According to recent literatures, breast cancer stem cells (BCSCs) were considered contributing to drug resistance, besides, microRNAs (miRNAs) could regulate proteins associated with drug resistance in human breast cancer. To further understand the inner mechanism of drug resistance in breast cancer and look for remedy methods, we referred to bioinformatic analysis and predicted that signal transducer and activator of transcription 3 (STAT3) and miR-124 was overexpressed in MCF7-R cells (MCF7 cells resistant to DOX) compared with MCF cells. Expression levels of RNA and protein were separately determined by qRT-PCR and western blot. Dual luciferase assay was performed to verify the targeting relationship between STAT3 and miR-124. Optical density (OD) values and apoptotic rates of cells were respectively determined via MTT assays and flow cytometric analysis. Cell invasion was detected to verify drug resistance. Results of above assays indicated that STAT3 was highly expressed in MCF7-R cells than in MCF7 cell lines and affected doxorubicin resistance of BCSCs, and miR-124 reversed the doxorubicin resistance of breast cancer stem cells through targeting STAT3 to control the HIF-1 signaling pathway. To conclude, this research may be valuable for the treatment of breast cancer as the restoration of miR-124 and inhibition of STAT3 could be applied to therapeutic strategy and help overcome drug resistance.

Loss of ALDH1L1 folate enzyme confers a selective metabolic advantage for tumor progression

ALDH1L1 (cytosolic 10-formyltetrahydrofolate dehydrogenase) is the enzyme in folate metabolism commonly downregulated in human cancers. One of the mechanisms of the enzyme downregulation is methylation of the promoter of the ALDH1L1 gene. Recent studies underscored ALDH1L1 as a candidate tumor suppressor and potential marker of aggressive cancers. In agreement with the ALDH1L1 loss in cancer, its re-expression leads to inhibition of proliferation and to apoptosis, but also affects migration and invasion of cancer cells through a specific folate-dependent mechanism involved in invasive phenotype. A growing body of literature evaluated the prognostic value of ALDH1L1 expression for cancer disease, the regulatory role of the enzyme in cellular proliferation, and associated metabolic and signaling cellular responses. Overall, there is a strong indication that the ALDH1L1 silencing provides metabolic advantage for tumor progression at a later stage when unlimited proliferation and enhanced motility become critical processes for the tumor expansion. Whether the ALDH1L1 loss is involved in tumor initiation is still an open question.

Upregulation of stem cell markers ALDH1A1 and OCT4 as potential biomarkers for the early detection of cervical carcinoma

Previous studies have reported the upregulation of stem cell biomarkers that are associated with tumorigenesis, in particular with cancer infiltration, recurrence and metastasis. Infection by human papilloma virus (HPV) is the main etiopathological factor of cervical carcinogenesis, but the expression of stem cell markers in cervical carcinoma and HPV infection have yet to be investigated so far. A total of 94 cases of fresh cervical tissues, 116 cases of paraffin-embedded cervical specimens and 72 cases of peripheral blood samples were collected from Uighur women who were either diagnosed with cervical squamous cell carcinoma (SCC) or cervical intraepithelial neoplasia (CIN) II-III, or from healthy subjects (negative controls, NC). HPV infection was detected in tissue DNA by polymerase chain reaction (PCR) with a HPV genotyping kit. The mRNA expression levels of aldehyde dehydrogenase 1 family member A1 (ALDH1A1), nanog homeobox (NANOG), POU class 5 homeobox 1 (OCT4), SRY-box 2 (SOX2) and twist family BHLH transcription factor 1 (Twist1) were determined using reverse transcription-quantitative PCR (RT-qPCR). Histological analysis was performed in order to examine the protein expression of ALDH1A1 and OCT4 in paraffin-embedded tissue specimens by immunohistochemical staining and the plasma levels of those two proteins was measured by ELISA. RT-qPCR analysis indicated a significant increase in the mRNA expression of ALDH1A1 and OCT4 in CIN II-III and SCC tissue specimens compared with NC (P<0.05). Although the expression levels of NANOG, SOX2 and Twist1 were significantly higher in SCC compared with NC (P<0.05), no significant difference was revealed in CIN II-III tissues compared with SCC or NC (P>0.05). Subsequent analysis by immunohistochemistry staining confirmed that the upregulation of ALDH1A1 and OCT4 was also significantly increased in SCC and CIN II-III compared with controls at the protein level. Notably, ELISA analysis detected significantly higher levels of ALDH1A1 and OCT4 in the peripheral blood (plasma) of patients with SCC compared with healthy subjects. The upregulation of stem cell markers ALDH1A1 and OCT4 in cervical carcinoma and its precursor lesions, in particular in the peripheral blood, indicates that ALDH1A1 and OCT4 may serve as biomarkers for the early detection of cervical carcinoma or for the monitoring of treatment of patients.

Distinct prognostic values of mRNA expression of glutathione peroxidases in non-small cell lung cancer

Introduction

Glutathione peroxidases (GPxs) constitutes an enzyme family which has the ability to reduce free hydrogen peroxide to water and lipid hydroperoxides to their corresponding alcohols, and its main biological roles are to protect organisms from oxidative stress-induced damage. GPxs include eight members in different tissues of the body, and they play essential roles in carcinogenesis. However, the prognostic value of individual GPx in non-small cell lung cancer (NSCLC) remains elusive.

Materials and methods

In the current study, we investigated the prognostic value of GPxs in NSCLC patients through the “Kaplan–Meier plotter” database, wherein updated gene expression data and survival information from a total of 1,926 NSCLC patients are included.

Results

High expression of GPx1 mRNA was correlated with worse overall survival (OS) in adenocarcinoma patients. High expression of GPx2 mRNA was correlated with worse OS for all NSCLC patients. In contrast, high expression of GPx3 mRNA was associated with better OS for all NSCLC patients. High expression of GPx4 mRNA was significantly correlated with worsening adenocarcinoma in these patients. GPx5 mRNA high expression correlated with worsening OS for all NSCLC patients.

Discussion

The current findings of prognostic values of individual mRNA expression of GPxs in NSCLC patients indicate some GPxs may have prognostic value in NSCLC patients, and this needs further study.

Prognostic roles of Notch receptor mRNA expression in human ovarian cancer

Aberrant activation of Notch signaling pathway has been correlated with high grade ovarian carcinoma and carcinogenesis. However, the predictive and prognostic values of Notch signaling pathway in ovarian cancer patients remains unclear. We utilize “The Kaplan-Meier plotter” (KM plotter) background database to access the prognostic values including overall survival (OS), progression-free survival (PFS), as well as post-progression survival (PPS) of four Notch receptor mRNA expression in ovarian cancer patients. Notch1 mRNA high expression was not correlated with OS, PFS and PPS for all ovarian cancer patients, but significantly correlated with poor PFS in TP53 wild type and favorite PFS in TP53 mutation type ovarian cancer patients. Notch2 mRNA high expression was significantly correlated with poor PFS for all ovarian cancer patients, especially in grade II patients. Notch3 mRNA high expression was significantly correlated with favorite PFS for all ovarian cancer patients. Notch4 mRNA high expression was significantly correlated with favorite OS, but not PFS and PPS for all ovarian cancer patients. The results strongly support that there are distinct prognostic values of four Notch receptor mRNA expression in ovarian cancer patients.

Characterization of human gastric adenocarcinoma cell lines established from peritoneal ascites

The three cell lines, designated as gastric cancer (GC)1401, GC1415 and GC1436 were derived from peritoneal effusions from patients with gastric adenocarcinoma. Cell lines were established in tissue culture and in immunodeficient, non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice. All cell lines were cultured in Dulbecco's modified Eagle's medium supplemented with 5% fetal bovine serum. These cell lines were grown as an adherent monolayer with doubling time ranging between 25 h (GC1436 cell line) and 30–34 h (GC1401 and GC1415, respectively). All cells showed morphological features of epithelial-like cells, forming sheets of polygonal cells. Chromosomal analysis showed that the modal numbers ranged from 52 (GC1401), 51–56 (GC1415) and 106 (GC1436). High heterogeneity, resulting from several structural and numerical chromosomal abnormalities were evident in all cell lines. The surface marker expression suggested a tumor origin of the cells, and indicated the intestinal phenotype of a GC (CD10⁺, MUC1). All three cell lines were tumorigenic but not metastatic, in vivo, in NOD/SCID mice. The lack of metastatic potential was suggested by the lack of aldehyde dehydrogenase 1A1 activity. In conclusion, these newly established GC cell lines widen the feasibility of the functional studies on biology of GC as well as drug testing for potential therapeutic purposes.

Prognostic values of excision repair cross-complementing genes mRNA expression in ovarian cancer patients

Excision repair cross-complementing (ERCC) genes, key components of the nucleotide excision repair pathway, are regarded as crucial factors for DNA repair capacity. Previous studies have investigated prognostic values of ERCC genes in a number of malignancies. However, the relationship between ERCC genes and prognosis of ovarian cancer patients remains controversial. Therefore, in the current study, we systematically analyze the prognostic values of ERCC genes in ovarian cancer by the Kaplan-Meier plotter, which includes updated gene expression data and survival information of 1656 ovarian cancer patients. Our results showed that high expression of ERCC1 and ERCC8 mRNA was related to a worse overall survival among ovarian cancer patients, especially in late stage and poor differentiation serous ovarian patients. Increased ERCC4 mRNA expression indicated a better overall survival among serous ovarian cancer patients. The other ERCC genes were uncorrelated with prognosis in ovarian cancer. These results indicate that some ERCC genes have critical prognostic values in ovarian cancer.

ALDH1L1 and ALDH1L2 Folate Regulatory Enzymes in Cancer

Epidemiological studies implicate excess ethanol ingestion as a risk factor for several cancers and support the concept of a synergistic effect of chronic alcohol consumption and folate deficiency on carcinogenesis. Alcohol consumption affects folate-related genes and enzymes including two major folate-metabolizing enzymes, ALDH1L1 and ALDH1L2. ALDH1L1 (cytosolic 10-formyltetrahydrofolate dehydrogenase) is a regulatory enzyme in folate metabolism that controls the overall flux of one-carbon groups in folate-dependent biosynthetic pathways. It is strongly and ubiquitously down-regulated in malignant tumors via promoter methylation, and recent studies underscored this enzyme as a candidate tumor suppressor and potential marker of aggressive cancers. A related enzyme, ALDH1L2, is the mitochondrial homolog of ALDH1L1 encoded by a separate gene. In contrast to its cytosolic counterpart, ALDH1L2 is expressed in malignant tumors and cancer cell lines and was implicated in metastasis regulation. This review discusses the link between folate and cancer, modifying effects of alcohol consumption on folate-associated carcinogenesis, and putative roles of ALDH1L1 and ALDH1L2 in this process.

Upregulation of ALDH1B1 promotes tumor progression in osteosarcoma

Osteosarcoma (OS) is the most common primary malignant bone tumor in childhood and adolescence with poor prognosis. The mechanism underlying tumorigenesis and development of OS is largely unknown. ALDH1B1 has been reported to involve in many kinds of human cancers and functions as an oncogene, but the role of ALDH1B1 in OS has not been investigated comprehensively. In the present study, we aimed to examine clinical value and biological function of ALDH1B1 in OS. Firstly, we investigated the roles of ALDH1B1 on an OS tissue microarray (TMA) as well as two OS cohorts from GEO database. We found that ALDH1B1 was significantly up-regulated in OS tissues and was independently associated with poor prognosis. Moreover, ALDH1B1 silencing could suppress the proliferation, migration, invasion in vitro and inhibit the growth of xenograft tumor and of OS cells in vivo. Additional, ALDH1B1 knockdown increased the apoptosis rate and lead to cell cycle arrest in G1 stage of OS cell in vitro. More importantly, the inhibition of ALDH1B1 expression could increase the sensitivity of OS cells to chemotherapy, which suggested that ALDH1B1 might be served as a therapeutic target to reverse drug resistance in chemotherapy in OS patients. Taken together, our founding suggested that ALDH1B1 contributes to OS tumor progression and drug resistance, which may represent a novel prognostic marker and potential therapeutic target for OS patients.

Prognostic roles of mRNA expression of notch receptors in non-small cell lung cancer

Notch signalling is aberrantly activated in human non-small cell lung cancer (NSCLC). Nevertheless, the prognostic roles of mRNA expression of four Notch receptors in NSCLC patients remain elusive. In this report, we reported the prognostic roles of Notch receptors in a total of 1,926 NSCLC patients through “The Kaplan-Meier plotter” (KM plotter) database which is capable to assess the effect of 22,277 genes on survival of NSCLC patients. We found that mRNA high expression level of Notch1 was associated with better overall survival (OS) for all NSCLC patients, hazard ratio (HR) 0.78 (0.69-0.89), p=0.00019, better OS in adenocarcinoma (Ade) patients, HR 0.59 (0.46-0.75), p=1.5e-05, as well as in squamous cell carcinoma (SCC) patients, HR 0.78 (0.62-0.99), p=0.044. mRNA high expression levels of Notch2 and Notch3 were associated with worsen OS for all NSCLC patients, as well as in Ade, but not in SCC patients. mRNA high expression level of Notch4 was not found to be associated with to OS for all NSCLC patients. In addition, mRNA high expression levels of Notch2, Notch3, but Notch4 are significantly associated with the NSCLC patients who have different smoking status. Our results indicate that mRNA expression of Notch receptors may have distinct prognostic values in NSCLC patients. These results will benefit for developing tools to accurately predict the prognosis of NSCLC patients.

Aldehyde dehydrogenase 1 (ALDH1) isoform expression and potential clinical implications in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent and life-threatening malignancies worldwide. There are few diagnostic and prognostic biomarkers and druggable targets for HCC. Aldehyde dehydrogenase 1 (ALDH1) is a marker of stem cells in a variety of cancers, but the mRNA levels and prognostic value of ALDH1 isoforms in HCC patients remain unknown. In the present study, gene ontology annotation of the ALDH1 family was performed using the Database for Annotation, Visualization and Integrated Discovery (DAVID), and the gene pathway analsis was performed using GeneMANIA software. The initial prognostic value of ALDH1 expression in 360 HCC patients was assessed using the OncoLnc database. The expression levels of ALDH1 isoforms in normal liver tissues and clinical specimens of cancer vs. normal control datasets were determined using the GTEx and Oncomine databases, respectively. We then analyzed the prognostic value of ALDH1 expression in 212 hepatitis B virus (HBV)-related HCC patients using the GEO database. We found that the ALDH1 isoform showed high aldehyde dehydrogenase activity. The ALDH1A1, ALDH1B1, and ALDH1L1 genes encoded for the ALDH1 enzyme. High ALDH1B1 expression had protective qualities in HCC patients. Moreover, HBV-related HCC patients who showed high ALDH1L1 gene expression had a better clinical outcomes. In addition, high ALDH1A1 expression was associated with a 57-month recurrence-free survival in HBV-related HCC patients. High ALDH1B1 expression was protective for HCCs with multiple nodules and high serum alpha-fetoprotein (AFP) level. Furthermore, high serum AFP levels contributed to lower ALDH1L1. ALDH1A1, ALDH1B1, and ALDH1L1, all of which were considered promising diagnostic and prognostic markers as well as potential drug targets.

ALDH1L1 variant rs2276724 and mRNA expression predict post-operative clinical outcomes and are associated with TP53 expression in HBV-related hepatocellular carcinoma

Aldehyde dehydrogenase 1 family member L1 (ALDH1L1) is downregulated in hepatocellular carcinoma (HCC) tumors, and its decreased expression is associated with the poor prognosis of HCC patients. We, therefore, evaluated the effect of single nucleotide polymorphisms (SNPs) of ALDH1L1, and its mRNA expression on the survival of hepatitis B virus (HBV)-related HCC patients and the association with tumor protein p53 (TP53) expression. ALDH1L1 SNPs in 415 HBV-related HCC patients were genotyped via direct sequencing. Expression profile chip datasets and survival information were obtained from GSE14520. The C allele (CT/CC) carriers of rs2276724 were significantly associated with a favorable prognosis [adjusted P=0.040; adjusted hazard ratio (HR)=0.725; 95% confidence interval (CI)=0.533–0.986]. Joint-effect analyses suggested that the CT/CC genotype of rs2276724 in TP53-negative patients was significantly associated with a decreased risk of death, compared to the TT genotype of rs2276724 in TP53-positive patients (adjusted P=0.037; adjusted HR=0.621; 95% CI=0.396–0.973). Furthermore, low expression of ALDH1L1 predicted a poor prognosis for the HBV-related HCC patients (adjusted P=0.04 for disease-free survival; adjusted P=0.001 for overall survival). Patients with high ALDH1L1 expression and low TP53 expression were significantly associated with a decreased risk of recurrence and death, and patients with a high TP53 expression were also significantly associated with a decreased risk of death in HBV-related HCC, compared with low ALDH1L1 and low TP53 expression. Our results suggest that ALDH1L1 may be a biomarker for predicting postoperative clinical outcomes. Moreover, ALDH1L1-rs2276724 and mRNA expression were associated with TP53 expression in HBV-related HCC patients.

Expression and associations of TRAF1, BMI-1, ALDH1, and Lin28B in oral squamous cell carcinoma

Tumor necrosis factor receptor-associated factor 1, an adaptor protein of tumor necrosis factor 2, is involved in classical nuclear factor (NF)-κB activation and lymphocyte recruitment. However, less is known about the expression and association of tumor necrosis factor receptor-associated factor 1 with cancer stem cell markers in oral squamous cell carcinoma. This study aimed to investigate the expression of tumor necrosis factor receptor-associated factor 1 and stem cell characteristic markers (lin28 homolog B, B cell-specific Moloney murine leukemia virus integration site 1, and aldehyde dehydrogenase 1) in oral squamous cell carcinoma and analyze their relations. Paraffin-embedded tissues of 78 oral squamous cell carcinomas, 39 normal oral mucosa, and 12 oral dysplasia tissues were employed in tissue microarrays, and the expression of tumor necrosis factor receptor-associated factor 1, B cell-specific Moloney murine leukemia virus integration site 1, aldehyde dehydrogenase 1, and lin28 homolog B was measured by immunohistostaining and digital pathological analysis. The expression of tumor necrosis factor receptor-associated factor 1 was higher in the oral squamous cell carcinoma group as compared with the expression in the oral mucosa (p < 0.01) and oral dysplasia (p < 0.001) groups. In addition, the expression of tumor necrosis factor receptor-associated factor 1 was associated with those of B cell-specific Moloney murine leukemia virus integration site 1, aldehyde dehydrogenase 1, and lin28 homolog B (p = 0.032, r² = 0.109; p < 0.0001, r² = 0.64; and p < 0.001, r² = 0.16) in oral squamous cell carcinoma. The patient survival rate was lower in the highly expressed tumor necrosis factor receptor-associated factor 1 group, although the difference was not significant. The clustering analysis showed that tumor necrosis factor receptor-associated factor 1 was most related to aldehyde dehydrogenase 1. These findings suggest that tumor necrosis factor receptor-associated factor 1 has potential direct/indirect regulations with the cancer stem cell markers in oral squamous cell carcinoma, which may help in further analysis of the cancer stem cell characteristics.

Combinatorial Ranking of Gene Sets to Predict Disease Relapse: The Retinoic Acid Pathway in Early Prostate Cancer

Background

Quantitative high-throughput data deposited in consortia such as International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA) present opportunities and challenges for computational analyses.

Methods

We present a computational strategy to systematically rank and investigate a large number (2¹⁰–2²⁰) of clinically testable gene sets, using combinatorial gene subset generation and disease-free survival (DFS) analyses. This approach integrates protein–protein interaction networks, gene expression, DNA methylation, and copy number data, in association with DFS profiles from patient clinical records.

Results

As a case study, we applied this pipeline to systematically analyze the role of ALDH1A2 in prostate cancer (PCa). We have previously found this gene to have multiple roles in disease and homeostasis, and here we investigate the role of the associated ALDH1A2 gene/protein networks in PCa, using our methodology in combination with PCa patient clinical profiles from ICGC and TCGA databases. Relationships between gene signatures and relapse were analyzed using Kaplan–Meier (KM) log-rank analysis and multivariable Cox regression. Relative expression versus pooled mean from diploid population was used for z-statistics calculation. Gene/protein interaction network analyses generated 11 core genes associated with ALDH1A2; combinatorial ranking of the power set of these core genes identified two gene sets (out of 2¹¹ − 1 = 2,047 combinations) with significant correlation with disease relapse (KM log rank p < 0.05). For the more significant of these two sets, referred to as the optimal gene set (OGS), patients have median survival 62.7 months with OGS alterations compared to >150 months without OGS alterations (p = 0.0248, hazard ratio = 2.213, 95% confidence interval = 1.1–4.098). Two genes comprising OGS (CYP26A1 and RDH10) are strongly associated with ALDH1A2 in the retinoic acid (RA) pathways, suggesting a major role of RA signaling in early PCa progression. Our pipeline complements human expertise in the search for prognostic biomarkers in large-scale datasets.

Prognostic values of four Notch receptor mRNA expression in gastric cancer

Notch ligands and receptors are frequently deregulated in several human malignancies including gastric cancer. The activation of Notch signaling has been reported to contribute to gastric carcinogenesis and progression. However, the prognostic roles of individual Notch receptors in gastric cancer patients remain elusive. In the current study, we accessed the prognostic roles of four Notch receptors, Notch 1-4, in gastric cancer patients through "The Kaplan-Meier plotter" (KM plotter) database, in which updated gene expression data and survival information include a total of 876 gastric cancer patients. All four Notch receptors' high mRNA expression was found to be correlated to worsen overall survival (OS) for all gastric cancer patients followed for 20 years. We further accessed the prognostic roles of individual Notch receptors in different clinicopathological features using Lauren classification, pathological grades, clinical grades, HER2 status and different choices of treatments of gastric cancer patients. These results indicate that there are critical prognostic values of the four Notch receptors in gastric cancer. This information will be useful for better understanding of the heterogeneity and complexity in the molecular biology of gastric cancer and to develop tools to more accurately predict their prognosis.

The prognostic roles of ALDH1 isoenzymes in gastric cancer

Increased aldehyde dehydrogenase 1 (ALDH1) activity has been determined to be present in the stem cells of several kinds of cancers including gastric cancer (GC). Nevertheless, which ones of ALDH1's isoenzymes are leading to ALDH1 activity remains elusive. In this study, we examined the prognostic value and hazard ratio (HR) of individual ALDH1 isoenzymes in patients with GC using "The Kaplan-Meier plotter" database. mRNA high expression level of ALDH1A1 was not found to be significantly correlated with the overall survival (OS) of all patients with GC followed for 20 years, HR =0.86 (95% confidence interval [CI]: 0.7-1.05), P=0.13. mRNA high expression level of ALDH1A2 was also not significantly correlated with OS for all patients with GC, HR =1.13 (95% CI: 0.91-1.41), P=0.25. mRNA high expression level of ALDH1A3 was found to be significantly correlated with worsened OS in either intestinal-type patients, HR =2.24 (95% CI: 1.44-3.49), P=0.00026, or diffuse-type patients, HR =1.91 (95% CI: 1.02-3.59), P=0.04. Interestingly, mRNA high expression level of ALDH1B1 was found to be significantly correlated with better OS for all patients with GC, HR =0.66 (95% CI: 0.53-0.81), P=7.8e-05, and mRNA high expression level of ALDH1L1 was found to be significantly correlated with worsened OS for all patients with GC, HR =1.23 (95% CI: 1-1.51), P=0.048. Furthermore, our results also indicate that ALDH1A3 and ALDH1L1 are potential major contributors to the ALDH1 activity in GC, since mRNA high expression levels of ALDH1A3 and ALDH1L1 were found to be significantly correlated with worsened OS for all patients with GC. Based on our study, ALDH1A3 and ALDH1L1 are potential prognostic markers and therapeutic targets for patients with GC.

Mining distinct aldehyde dehydrogenase 1 (ALDH1) isoenzymes in gastric cancer

Aldehyde dehydrogenase 1 (ALDH1) consists of a family of intracellular enzymes, highly expressed in stem cells populations of leukemia and some solid tumors. Up to now, 6 isoforms of ALDH1 have been reported. However, the expression patterns and the identity of ALDH1 isoenzymes contributing to ALDH1 activity, as well as the prognostic values of ALDH1 isoenzymes in cancers all remain to be elucidated. Here, we studied the expressions of ALDH1 transcripts in gastric cancer (GC) compared with the normal controls using the ONCOMINE database. Through the Kaplan-Meier plotter database, which contains updated gene expression data and survival information of 876 GC patients, we also investigated the prognostic values of ALDH1 isoenzymes in GC patients. It was found that when compared with normal tissues, ALDH1A1 mRNA expression was downregulated, whereas ALDH1A3 and ALDH1B1 were upregulated in GC patients. In survival analyses, high ALDH1A1 and ALDH1B1 expressions were associated with better overall survival (OS) in all GC patients. In addition, high transcription activity of ALDH1A1 predicted better OS in gastric intestinal type adenocarcinoma, but not in diffuse gastric adenocarcinoma. GC patients with high mRNA level of ALDH1B1 showed better OS in gastric intestinal type, and worse OS in diffuse type. Oppositely, high transcription activities of ALDH1A2, ALDH1A3 and ALDH1L1 predicted worsen overall survival in GC patients, suggesting that these isoenzymes might be responsible mainly for the ALDH1 activities in GC. These data provides ALDH1A2, ALDH1A3 and ALDH1L1 as excellent potential targets for individualized treatment of GC patients.

Prognostic values of aldehyde dehydrogenase 1 isoenzymes in ovarian cancer

Aldehyde dehydrogenase 1 (ALDH1) activity has been used as a functional stem cell marker to isolate cancer stem cells in different cancer types, including ovarian cancer. However, which ALDH1’s isoenzymes are contributing to ALDH1 activity in ovarian cancer remains elusive. In addition, the prognostic value of an individual ALDH1 isoenzyme in ovarian cancer is not clear. Thus, we accessed the prognostic value of ALDH1 isoenzymes in ovarian cancer patients through the “Kaplan–Meier plotter” online database, which can be used to determine the effect of the genes on ovarian cancer prognosis. We found that high mRNA expression of five ALDH1 isoenzymes, such as ALDH1A1, ALDH1A2, ALDH1A3, ALDH1B1, and ALDH1L1, was not correlated with overall survival (OS) for all 1,306 ovarian cancer patients. In addition, all five of the ALDH1 isoenzymes’ high mRNA expression was found to be uncorrelated with OS in serous cancer or endometrioid cancer patients. However, ALDH1A3’s high mRNA expression is associated with worse OS in grade II ovarian cancer patients, hazard ratio (HR) 1.53 (1.14–2.07), P=0.005. ALDH1A2’s high mRNA expression is significantly associated with worse OS in TP53 wild-type ovarian cancer patients, HR 2.86 (1.56–5.08), P=0.00036. In addition, ALDH1A3’s high mRNA expression is significantly associated with better OS in TP53 wild-type ovarian cancer patients, HR 0.56 (0.32–1.00), P=0.04. Our results indicate that although ALDH1 isoenzyme mRNA might not be a prognostic marker for overall ovarian cancer patients, some isoenzymes, such as ALDH1A2 and ALDH1A3, might be a good prognostic marker for some types of ovarian cancer patients.

ALDH1A3, a metabolic target for cancer diagnosis and therapy

Metabolism reprogramming has been linked with the initiation, metastasis, and recurrence of cancer. The aldehyde dehydrogenase (ALDH) family is the most important enzyme system for aldehyde metabolism. The human ALDH family is composed of 19 members. ALDH1A3 participates in various physiological processes in human cells by oxidizing all-trans-retinal to retinoic acid. ALDH1A3 expression is regulated by many factors, and it is associated with the development, progression, and prognosis of cancers. In addition, ALDH1A3 influences a diverse range of biological characteristics within cancer stem cells and can act as a marker for these cells. Thus, growing evidence indicates that ALDH1A3 has the potential to be used as a target for cancer diagnosis and therapy.

Breast Cancer Stem Cell Isolation

Cells within the tumor are highly heterogeneous. Only a small portion of the cells within the tumor is capable to generate a new tumor. These cells are called cancer stem cells. Theoretically, cancer stem cells are originally from normal stem cells or early progenitor cells which accumulate the random mutations and undergo an altered version of the normal differentiation process. The cancer stem cell drives tumor progression and its recurrence. Thus, the technique to identify and purify the cancer stem cell is the key in any cancer stem cell research. In this protocol, we provide the basic technology of identification and purification of breast cancer stem cells as well as further functional assays to help the researchers achieve their research goals.

Distinct prognostic values of four-Notch-receptor mRNA expression in ovarian cancer

Notch signaling pathway includes ligands and Notch receptors, which are frequently deregulated in several human malignancies including ovarian cancer. Aberrant activation of Notch signaling has been linked to ovarian carcinogenesis and progression. In the current study, we used the "Kaplan-Meier plotter" (KM plotter) database, in which updated gene expression data and survival information from a total of 1306 ovarian cancer patients were used to access the prognostic value of four Notch receptors in ovarian cancer patients. Hazard ratio (HR), 95 % confidence intervals, and log-rank P were calculated. Notch1 messenger RNA (mRNA) high expression was not found to be correlated to overall survival (OS) for all ovarian cancer, as well as in serous and endometrioid cancer patients followed for 20 years. However, Notch1 mRNA high expression is significantly associated with worsen OS in TP53 wild-type ovarian cancer patients, while it is significantly associated with better OS in TP53 mutation-type ovarian cancer patients. Notch2 mRNA high expression was found to be significantly correlated to worsen OS for all ovarian cancer patients, as well as in grade II ovarian cancer patients. Notch3 mRNA high expression was found to be significantly correlated to better OS for all ovarian cancer patients, but not in serous cancer patients and endometrioid cancer patients. Notch4 mRNA high expression was not found to be significantly correlated to OS for all ovarian cancer patients, serous cancer patients, and endometrioid cancer patients. These results indicate that there are distinct prognostic values of four Notch receptors in ovarian cancer. This information will be useful for better understanding of the heterogeneity and complexity in the molecular biology of ovarian cancer and for developing tools to more accurately predict their prognosis. Based on our results, Notch1 could be a potential drug target of TP53 wild-type ovarian cancer and Notch2 could be a potential drug target of ovarian cancer.

Impaired aldehyde dehydrogenase 1 subfamily member 2A-dependent retinoic acid signaling is related with a mesenchymal-like phenotype and an unfavorable prognosis of head and neck squamous cell carcinoma

Background

An inverse correlation between expression of the aldehyde dehydrogenase 1 subfamily A2 (ALDH1A2) and gene promoter methylation has been identified as a common feature of oropharyngeal squamous cell carcinoma (OPSCC). Moreover, low ALDH1A2 expression was associated with an unfavorable prognosis of OPSCC patients, however the causal link between reduced ALDH1A2 function and treatment failure has not been addressed so far.

Methods

Serial sections from tissue microarrays of patients with primary OPSCC (n = 101) were stained by immunohistochemistry for key regulators of retinoic acid (RA) signaling, including ALDH1A2. Survival with respect to these regulators was investigated by univariate Kaplan-Meier analysis and multivariate Cox regression proportional hazard models. The impact of ALDH1A2-RAR signaling on tumor-relevant processes was addressed in established tumor cell lines and in an orthotopic mouse xenograft model.

Results

Immunohistochemical analysis showed an improved prognosis of ALDH1A2^high OPSCC only in the presence of CRABP2, an intracellular RA transporter. Moreover, an ALDH1A2^highCRABP2^high staining pattern served as an independent predictor for progression-free (HR: 0.395, p = 0.007) and overall survival (HR: 0.303, p = 0.002), suggesting a critical impact of RA metabolism and signaling on clinical outcome. Functionally, ALDH1A2 expression and activity in tumor cell lines were related to RA levels. While administration of retinoids inhibited clonogenic growth and proliferation, the pharmacological inhibition of ALDH1A2-RAR signaling resulted in loss of cell-cell adhesion and a mesenchymal-like phenotype. Xenograft tumors derived from FaDu cells with stable silencing of ALDH1A2 and primary tumors from OPSCC patients with low ALDH1A2 expression exhibited a mesenchymal-like phenotype characterized by vimentin expression.

Conclusions

This study has unraveled a critical role of ALDH1A2-RAR signaling in the pathogenesis of head and neck cancer and our data implicate that patients with ALDH1A2^low tumors might benefit from adjuvant treatment with retinoids.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0476-0) contains supplementary material, which is available to authorized users.

Distinct prognostic values and potential drug targets of ALDH1 isoenzymes in non-small-cell lung cancer

Increased aldehyde dehydrogenase 1 (ALDH1) activity has been found in the stem cell populations of leukemia and some solid tumors including non-small-cell lung cancer (NSCLC). However, which ALDH1’s isoenzymes are contributing to ALDH1 activity remains elusive. In addition, the prognostic value of individual ALDH1 isoenzyme is not clear. In the current study, we investigated the prognostic value of ALDH1 isoenzymes in NSCLC patients through the Kaplan–Meier plotter database, which contains updated gene expression data and survival information from a total of 1,926 NSCLC patients. High expression of ALDH1A1 mRNA was found to be correlated to a better overall survival (OS) in all NSCLC patients followed for 20 years (hazard ratio [HR] 0.88 [0.77–0.99], P=0.039). In addition, high expression of ALDH1A1 mRNA was also found to be correlated to better OS in adenocarcinoma (Ade) patients (HR 0.71 [0.57–0.9], P=0.0044) but not in squamous cell carcinoma (SCC) patients (HR 0.92 [0.72–1.16], P=0.48). High expression of ALDH1A2 and ALDH1B1 mRNA was found to be correlated to worser OS in all NSCLC patients, as well as in Ade, but not in SCC patients. High expression of both ALDH1A3 and ALDH1L1 mRNA was not found to be correlated to OS in all NSCLC patients. These results strongly support that ALDH1A1 mRNA in NSCLC is associated with better prognosis. In addition, our current study also supports that ALDH1A2 and ALDH1B1 might be major contributors to the ALDH1 activity in NSCLC, since high expression of ALDH1A2 and ALDH1B1 mRNA was found to be significantly correlated to worser OS in all NSCLC patients. Based on our study, ALDH1A2 and ALDH1B1 might be excellent potential drug targets for NSCLC patients.